JP2010157532A - Method of manufacturing semiconductor device, and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily form an organic TFT (Thin Film Transistor), in which the position shift of an electrode is extremely small, at short times. <P>SOLUTION: A method of manufacturing a semiconductor device includes: a first step of forming a first conductive layer on an insulating substrate; a second step of forming a gate insulating film; a third step of forming a monomolecular film composed of a photosensitive silane coupling agent on the gate insulating film; a fourth step of exposing only a predetermined region in the monomolecular film; a fifth step of forming a second conductive layer on the region which has been exposed in the fourth process, in the monomolecular film; and a sixth step of forming a semiconductor layer composed of an organic semiconductor, meanwhile the sixth step is carried out either after the fifth process or between the first step and second step. In the fifth step, the second conductive layer is formed by using a conductive material in a solution state, and in the third step, the monomolecular film is formed by using a solution prepared by dissolving the photosensitive silane coupling agent and organic acid into an organic solvent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a semiconductor device manufacturing method and a semiconductor device, and more particularly to a technique effective when applied to a semiconductor device manufacturing method in which a semiconductor layer is formed of an organic semiconductor.

  Some conventional semiconductor devices include, for example, semiconductor elements such as MISFETs and wirings formed on the surface of an insulating substrate such as a glass substrate. As described above, the MISFET formed on the surface of the insulating substrate has electrodes and semiconductor layers formed of thin films, and is generally called TFT (Thin Film Transistor).

  TFT has advantages such as low power consumption and space saving. In recent years, it has been used as an active element (sometimes called a switching element) for liquid crystal displays used in portable electronic devices such as mobile phones, notebook computers, and PDAs. Has been.

  In recent years, for example, it has been studied to replace a semiconductor device which has been conventionally manufactured using a silicon wafer with a semiconductor device in which a TFT, wiring, or the like is formed on the surface of an insulating substrate. As such an example, for example, there is a drive circuit (driver circuit) for driving a liquid crystal display device. In recent years, it has been studied to incorporate a driver circuit having a TFT in a liquid crystal display panel.

  Incidentally, the semiconductor layer of the TFT in the above semiconductor device is usually formed of an inorganic semiconductor material typified by crystalline silicon or amorphous silicon. This is because a conventional semiconductor device manufacturing process or manufacturing technique can be used. However, when a semiconductor manufacturing process is used, a processing temperature when forming a semiconductor film is 350 ° C. or higher, so that there are restrictions on an insulating substrate that can be used. In particular, a flexible substrate typified by plastic often has a heat-resistant temperature of 350 ° C. or less, and it is difficult to form a TFT having an inorganic semiconductor layer using a normal semiconductor manufacturing process.

  In order to solve such problems, research and development of TFTs using organic semiconductor materials (hereinafter referred to as organic TFTs) have been promoted in recent years. The organic semiconductor film used for the organic TFT can be formed at a lower temperature (for example, about 120 ° C.) than an inorganic semiconductor film such as a silicon film. Therefore, it is possible to form an insulating substrate with low heat resistance such as plastic, which increases the possibility of realizing a flexible semiconductor device that is not available in the past, or a completely new type of electronic device using them.

  The method of forming an organic semiconductor film of an organic TFT varies depending on the type of organic semiconductor material, and includes printing methods such as an inkjet method, spin coating methods, spray methods, transfer methods, vapor deposition methods, dipping methods, and cast methods. The optimal method is used. For example, a low molecular compound such as a pentacene derivative is generally formed by a vapor deposition method or the like, and a high molecular compound such as a polythiophene derivative is generally formed from a solution.

  In addition, as a method for manufacturing a semiconductor device having an organic TFT, for example, a method of forming an organic semiconductor film by utilizing a capillary phenomenon and reducing the amount of organic semiconductor material used has been proposed (for example, see Patent Document 1). reference.).

  In addition, in the method of manufacturing a semiconductor device having an organic TFT, other than that, by using a printing technique typified by, for example, an inkjet method, a microdispensing method, a transfer method, etc., a small amount of organic semiconductor material can be used without waste. Research and development is underway to form semiconductor layers and further reduce costs. Furthermore, in the manufacturing method of a semiconductor device having an organic TFT, research and development for forming not only an organic semiconductor layer but also electrodes and wiring by a printing method has been started.

  However, with the current normal printing technology, the alignment accuracy is about 20 μm, and even with the latest technology, it is about several μm. Therefore, at present, it is difficult to form fine TFTs using a printing technique. In the case of a fine TFT, in particular, if the positional deviation between the gate electrode and the source / drain electrode occurs, for example, the parasitic capacitance increases or the performance of individual TFTs varies when a plurality of TFTs are formed simultaneously. The problem of doing becomes remarkable. For example, in the case of the ink jet method, such a positional shift is said to occur when the material ejected from the nozzle flies to the substrate. In addition, for example, in the case of a transfer method, such a positional shift is said to occur when a material is transferred from a transfer roll to a substrate.

  Therefore, at present, the printing technology is used for the formation of the organic semiconductor film and the wiring, the conventional semiconductor device manufacturing technology for the formation of the insulating film and the contact hole, and the formation of the electrode is the printing or the conventional semiconductor device. The manufacturing technology is used. In this case, since both types are combined, a wide range of manufacturing equipment such as photolithography-related equipment, printing equipment, film-forming equipment, etching equipment, etc., and a photomask is required for contact hole formation process, electrode formation process, etc. Therefore, the manufacturing cost increases.

As a countermeasure, a method without misalignment that does not require a photomask has begun to be studied. For example, a gate without misalignment is formed by photolithography from the back surface using a photosensitive composition and a source / drain electrode as a mask. A method of forming an electrode has been proposed (see, for example, Patent Document 2).
JP 2004-80026 JP JP 2003-158134 A

  It can be said that the TFT formation method described in Patent Document 2 is suitable for a fine organic TFT formation method because there is no positional deviation between the gate electrode and the source / drain electrodes.

  However, since this forming method includes a photolithography process for the photosensitive composition, it includes steps such as application, heating, exposure, and development of the photosensitive composition, and it takes time and is used in each process. Since an apparatus etc. are also required, there exists a problem that manufacturing cost increases.

  Further, when a photolithography process of a photosensitive composition used in a normal semiconductor process is used, for example, a special insulating substrate such as a flexible substrate may not be used. Further, when an organic substrate such as plastic is used as the insulating substrate, there is a problem that the insulating substrate is dissolved in the solvent of the photosensitive composition, for example.

  In recent years, a method using a photosensitive self-assembled film (hereinafter referred to as photosensitive SAM) as a photosensitive composition has been studied to solve such problems. The photosensitive SAM is characterized in that an unexposed unexposed portion is water repellent and the exposed portion becomes hydrophilic. Therefore, using this feature, if the conductive material can be selectively printed on the hydrophilic portion to form electrodes and wiring, the development process can be omitted, and the formation time and production cost can be reduced accordingly. It becomes possible.

  As photosensitive SAMs, for example, silane coupling agents having a perfluoroalkyl group and silane coupling agents having a photosensitive group of a photosensitive composition typified by a resist have been reported.

  The photosensitive SAM having a perfluoroalkyl group uses, for example, a reaction that cleaves the main chain using light having a short wavelength of about 200 nm in order to develop hydrophilicity. However, since a normal flexible substrate does not transmit light of 300 nm or less, it does not react in backside exposure using the flexible substrate. On the other hand, some photosensitive SAMs having a resist photosensitive group can react with light transmitted through a flexible substrate because the exposure wavelength can be adjusted by changing the photosensitive group.

  However, conventional photosensitive SAM film formation is performed, for example, by immersing a desired insulating substrate in a solution in which photosensitive SAM is dissolved in an organic solvent such as toluene and heating it at a temperature of 100 ° C. or higher for about 1 hour. It was. Therefore, when a plastic substrate or the like is used as the insulating substrate, there is a concern that the substrate may be deformed. Furthermore, since it takes about 1 hour to form the photosensitive SAM alone, there is a problem that the time required for forming the TFT element becomes enormous.

  An object of the present invention is to provide a method of manufacturing a semiconductor device capable of easily forming an organic TFT with extremely small displacement of electrodes in a short time.

  Another object of the present invention is to provide a semiconductor device capable of reducing deterioration in characteristics of organic TFTs and variations in characteristics among a plurality of organic TFTs.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  The outline of typical inventions among the inventions disclosed in the present application will be described as follows.

(1) A method of manufacturing a semiconductor device including a step of forming a MISFET on an insulating substrate, wherein the step of forming the MISFET includes a first step of forming a first conductive layer on the insulating substrate. And a second step of forming a gate insulating film that covers or intersects the first conductive layer, and a photosensitive silane coupling agent is formed on the gate insulating film. A third step of forming a monomolecular film; a fourth step of exposing only a predetermined region of the monomolecular film that does not overlap the first conductive layer; and A fifth step of forming a second conductive layer on the region of the film exposed to light in the fourth step, after the fifth step, or after the first step and the second step. A semiconductor layer made of an organic semiconductor is performed at any time between And the fifth step forms the second conductive layer using a solution-like conductive material, and the third step is represented by the following structural formula 1. And the terminal on the side opposite to the side bonded to the methylene group (—CH ₂ —) of the end of A in the following structural formula 1 changes from a hydrophobic group to a hydrophilic group when exposed to light. A method for manufacturing a semiconductor device, wherein the monomolecular film is formed using a solution obtained by dissolving a silane coupling agent and an organic acid in an organic solvent.

  (2) In the method of manufacturing a semiconductor device according to (1), the sixth step is performed after the fifth step, and the first step forms a gate electrode of the MISFET, and Step 5 is a method of manufacturing a semiconductor device in which the source electrode and the drain electrode of the MISFET are formed.

  (3) In the method of manufacturing a semiconductor device of (1), the sixth step is performed between the first step and the second step, and the first step is a source of the MISFET. An electrode and a drain electrode are formed, and the fifth step is a method of manufacturing a semiconductor device in which a gate electrode of the MISFET is formed.

  (4) In the method of manufacturing a semiconductor device according to (1), the monomolecular film formed in the third step has a water contact angle of 90 degrees or more on a surface on which the second conductive layer is formed. And a method of manufacturing a semiconductor device in which the contact angle of water on the surface changes to 40 degrees or less when exposed to light.

  (5) In the method of manufacturing a semiconductor device according to (1), the second conductive layer of the monomolecular film is formed between the fourth step and the fifth step using an organic alkaline aqueous solution. A method for manufacturing a semiconductor device, comprising a seventh step of performing a surface treatment on the surface to be processed.

  (6) In the method of manufacturing a semiconductor device according to (1), the insulating substrate is a light-transmitting substrate, the first conductive layer is formed of a light-shielding conductor, and the insulating layer is The fourth step is performed on the opposite side of the insulating substrate from the surface on which the first conductive layer, the insulating layer, and the monomolecular film are formed. A method for manufacturing a semiconductor device, wherein the monomolecular film is irradiated with light from the surface.

  (7) In the method of manufacturing a semiconductor device according to (1), the fifth step is a semiconductor performed using any one of an inkjet method, a micro-dispensing method, a casting method, a dipping method, and a transfer method. Device manufacturing method.

  (8) In the method of manufacturing a semiconductor device according to (1), the first step, the second step, the third step, and the fifth step are each performed using a printing method. Manufacturing method.

  (9) The method for manufacturing a semiconductor device according to (1), wherein the insulating substrate is a resin substrate.

  (10) The method for manufacturing a semiconductor device according to (1), wherein the insulating substrate is a substrate made of a silicon compound.

  (11) The method for manufacturing a semiconductor device according to (1), wherein the insulating substrate is a substrate made of an organic compound.

  (12) A semiconductor device manufactured by the method for manufacturing a semiconductor device according to any one of (1) to (11).

(13) A semiconductor device having a plurality of MISFETs provided on an insulating substrate, wherein the MISFET covers a gate electrode provided on the insulating substrate and the whole of the gate electrode, or A gate insulating film intersecting with the gate electrode, a monomolecular film provided on the gate insulating film, and a source electrode, a drain electrode, and an organic semiconductor layer provided on the monomolecular film, The molecules constituting the monomolecular film each have a silicon atom bonded to a methylene group (—CH ₂ —) at an end portion on the interface side with the insulating layer, and the monomolecular film includes A first molecule in which a monovalent atom or group is bonded to the silicon atom, and a second molecule in which the monovalent atom or group is not bonded to the silicon atom, The number of molecules of the first molecule Semiconductor device more than.

  (14) In the semiconductor device of (13), the monomolecular film includes a first region that overlaps the source electrode or the drain electrode and a second region that does not overlap, and constitutes the monomolecular film. Among the molecules to be operated, a molecule in the first region and a molecule in the second region are different semiconductor devices in which the terminal group on the opposite side to the side closer to the insulating layer is different.

(15) A semiconductor device having a plurality of MISFETs provided on an insulating substrate, wherein the MISFET includes a source electrode and a drain electrode provided on the insulating substrate, and the source electrode and the drain electrode. An organic semiconductor layer covering the whole or intersecting the source electrode and the drain electrode; a gate insulating film provided on the organic semiconductor layer; and a monomolecular film provided on the gate insulating film; And a gate electrode provided on the monomolecular film, and the molecules constituting the monomolecular film are each a methylene group (—CH ₂ —) at an end of the interface with the insulating layer. And the monomolecular film includes a first molecule in which a monovalent atom or group is bonded to the silicon atom, and the monovalent atom or the silicon atom. There bound and a second molecule that is not the number of the second molecule, the semiconductor device is greater than the number of the first molecule.

  (16) In the semiconductor device of (15), the monomolecular film includes a first region that overlaps with the gate electrode and a second region that does not overlap, and is a molecule that constitutes the monomolecular film. The molecule in the first region and the molecule in the second region are different semiconductor devices in which the terminal group on the opposite side to the side closer to the insulating layer is different.

  (17) The semiconductor device according to (13) or (15), wherein the monomolecular film has a ratio of the first molecule to the second molecule of about 2: 8.

  (18) In the semiconductor device according to (13) or (15), the monomolecular film includes molecules having a total number of the monovalent atoms or groups bonded to the silicon atoms included in the monomolecular film. There are fewer semiconductor devices.

(19) In the semiconductor device of (13) or (15), the first molecule is a semiconductor device in which a methoxy group (—OCH ₃ ) is bonded to the silicon atom.

  (20) In the semiconductor device of (13) or (15), when the surface of the insulating substrate on which the gate electrode is formed is viewed, a gap or an overlap amount between the gate electrode and the source electrode, and A semiconductor device in which a gap or an overlap amount between a gate electrode and the source electrode is 1 μm or less, respectively.

  According to the method for manufacturing a semiconductor device of the present invention, it is possible to easily form an organic TFT with a very small displacement of electrodes in a short time.

  In addition, according to the semiconductor device of the present invention, it is possible to reduce the deterioration of characteristics of fine organic TFTs and the dispersion of characteristics among a plurality of organic TFTs.

Hereinafter, the present invention will be described in detail together with embodiments (examples) with reference to the drawings.
Note that, in the plurality of drawings referred to in the description below, the same reference numerals are given to components having the same function, and repeated description thereof is omitted.

FIG. 1 is a schematic plan view and a schematic cross-sectional view showing an example of a schematic configuration of an organic TFT formed by the method for manufacturing a semiconductor device of Example 1 according to the present invention.
1 is a schematic plan view showing an example of the planar configuration of the organic TFT, and (S) shown on the lower side is L1-L1 ′ in the upper figure (P). It is a schematic cross section which shows an example of the cross-sectional structure in a line.

  The manufacturing method of the semiconductor device of Example 1 includes a step of forming an organic TFT on an insulating substrate. At this time, the organic TFT formed on the insulating substrate includes, for example, a gate electrode 2, a gate insulating film 3, a self-assembled film 4, and a source electrode formed on the insulating substrate 1 as shown in FIG. 1. 5, a drain electrode 6, and an organic semiconductor film 7.

  The insulating substrate 1 is a substrate having high translucency, and is made of, for example, a silicon compound or an organic compound.

  The gate electrode 2 is a conductive film having a high light shielding property, and is made of, for example, a metal, a conductive metal oxide, or a conductive polymer. The gate electrode 2 is connected to the wiring 801.

  The gate insulating film 3 is an insulating film with high translucency, and is made of, for example, an insulating organic polymer or an insulating inorganic compound.

  The self-assembled film 4 has an affinity for water on the surface (the surface on which the source electrode 5 and the like are formed) of the first region 4a that overlaps the gate electrode 2 and the second region 4b that is outside thereof. Are different insulating films, for example, made of a photosensitive silane coupling agent. At this time, in the self-assembled film 4, the surface of the first region 4a exhibits water repellency (hydrophobicity), and the surface of the second region 4b exhibits hydrophilicity.

  The source electrode 5 and the drain electrode 6 are conductive films, and are made of, for example, a metal, a conductive metal oxide, or a conductive polymer. The source electrode 5 is connected to the wiring 802 and the drain electrode 6 is connected to the wiring 803.

  The organic semiconductor film 7 is made of an organic compound having semiconducting electrical properties, such as a polyacene derivative or a polythiophene derivative.

  The wirings 801, 802, and 803 are conductive films, and are made of, for example, a metal, a conductive metal oxide, or a conductive polymer.

  Although omitted in FIG. 1, a protective film covering the organic TFT, the wirings 801, 802, 803, and the like is formed on the insulating substrate 1.

  In the semiconductor device manufacturing method according to the first embodiment, an electronic circuit (integrated circuit) including a large number of elements including the organic TFT and a large number of wirings is formed on the insulating substrate 1. At this time, the configuration of the electronic circuit formed on the insulating substrate 1 is arbitrary, and can be appropriately changed according to the application of the semiconductor device. For this reason, in the first embodiment, a detailed description of specific applications and circuit configurations of the semiconductor device to be manufactured is omitted.

  In addition, the manufacturing method of the semiconductor device of Example 1 is a method for forming an organic TFT among a large number of elements and a large number of wirings formed on the insulating substrate 1, in particular, the formation of the self-organized film 4 of the organic TFT. Regarding the method. Therefore, in Example 1, only the part related to the method of forming the organic TFT in the method of manufacturing the semiconductor device will be described.

  In addition, the following description of the organic TFT forming method will be made by first explaining the outline of the organic TFT forming method (semiconductor device manufacturing method) of Example 1, and then the features of the organic TFT forming method of Example 1 and An example of the effect will be described.

2A to 2G are schematic views for explaining a method for forming an organic TFT in the method for manufacturing a semiconductor device according to the first embodiment.
FIG. 2A is a schematic plan view and a schematic cross-sectional view for explaining a step of forming a gate electrode. FIG. 2B is a schematic plan view and a schematic cross-sectional view for explaining a step of forming a gate insulating film. FIG. 2C is a schematic plan view and a schematic cross-sectional view for explaining a step of forming a monomolecular film of the photosensitive silane coupling agent. FIG. 2D is a schematic diagram illustrating an example of a bonding state between the gate insulating film and the photosensitive silane coupling agent. FIG. 2E is a schematic plan view and a schematic cross-sectional view for explaining an example of a method for exposing a part of the monomolecular film. FIG. 2F is a schematic plan view and a schematic cross-sectional view for explaining a process of forming the source electrode and the drain electrode. FIG. 2G is a schematic plan view and a schematic cross-sectional view for explaining a process of forming a wiring.

  2 (a) to 2 (c) and FIGS. 2 (e) to 2 (g) are examples of a planar configuration immediately after the respective steps in FIG. 2 (P) are completed. Is a schematic plan view showing an example of a cross-sectional configuration taken along line L1-L1 'of the upper figure (P).

  In the method for forming an organic TFT in the method for manufacturing a semiconductor device of Example 1, first, a gate electrode 2 is formed on the surface of an insulating substrate 1 as shown in FIG. At this time, as the insulating substrate 1, for example, a translucent insulating substrate made of polycarbonate is used. Further, the gate electrode 2 is formed by, for example, ink-jet printing, printing an ink in which gold (Au) nanoparticles are dispersed in a toluene solution, and then heating at 200 ° C. for 5 minutes. As the gold nanoparticle, for example, a surface of a metal core having a particle size of about 3.5 nm is covered with butanethiolate.

  The insulating substrate 1 is not limited to a polycarbonate substrate, and may be another plastic substrate, a glass substrate, or a quartz substrate. The material of the plastic substrate that can be used as the insulating substrate 1 includes, for example, polyethylene terephthalate, polyethylene naphthalate, polyetherimide, polyetherethersulfone, polyetheretherketone, polyphenylene sulfide, polyacrylate, polyimide in addition to polycarbonate. , Cellulose triacetate, and cellulose acetate propionate.

  Further, the gate electrode 2 shown in FIG. 2A has a T-shaped planar shape. Therefore, when printing ink, for example, it is divided into a first portion 2a and a second portion 2b, the first portion 2a is printed while moving the nozzle in the vertical direction, and the second portion 2b is a nozzle. It is desirable to print while moving in the horizontal direction. However, when ink is printed by the ink jet printing method, it is needless to say that printing may be performed without dividing the two portions 2a and 2b. Further, ink printing is not limited to the ink jet printing method, and may be performed by other printing methods.

  The gate electrode 2 is not limited to the formation method using the inkjet printing method, and is formed by other formation methods such as a formation method using any one of a micro-dispensing method, a dip method, a spin coating method, and a transfer method. May be.

  The gate electrode 2 is not limited to gold and may be formed of another metal, a conductive metal oxide, a conductive polymer, or the like, as long as it is a conductive film with high light shielding properties. Moreover, when forming the gate electrode 2 using a liquid conductive material, the solvent to be used is not limited to toluene. For example, methyl amyl ketone, ethyl lactate, cyclohexanone, propylene glycol monomethyl ether, propylene glycol-1-monomethyl It may be a general solvent for photosensitive compositions such as ether-2-acetate, ethers such as diethyl ether, acetone and tetrahydrofuran, alcohols such as toluene, chloroform and ethanol, or water. The solvent used may be a mixed solvent of two or more types.

  Further, the planar shape of the gate electrode 2 is not limited to the T-shape, and may be another shape.

Next, for example, as shown in FIG. 2B, a gate insulating film 3 intersecting with the first portion 2a of the gate electrode 2 is formed. The gate insulating film 3 is formed by, for example, printing an ink made of a 10 w% methyl isobutyl ketone solution of Poly (methyl silsesquioxane) by an ink jet printing method and heating at 150 ° C. for 20 minutes. At this time, the gate insulating film 3 is made of silicon oxide (SiO ₂ ).

  The gate insulating film 3 is not limited to the formation method using the ink jet printing method, and is formed by other formation methods such as a formation method using a micro-dispensing method, a dip method, a spin coating method, a transfer method, or the like. Also good.

  In addition, when forming the gate insulating film 3 made of silicon oxide, the gate insulating film 3 is not limited to the method using the ink made of the above solution but may be made of ink made of another solution.

  Further, since the gate insulating film 3 may be an insulating film having a light transmitting property, it is not limited to silicon oxide, and may be formed of other insulating inorganic compounds, insulating organic polymers, and the like. Insulating inorganic compounds that can be used as the gate insulating film 3 include, for example, silicon nitride, insulating metal oxide, and metal nitride in addition to the silicon oxide film. Insulating organic polymers that can be used as the gate insulating film 3 include, for example, polyimide derivatives, benzocyclobutene derivatives, photoacryl derivatives, polystyrene derivatives, polyvinyl phenol derivatives, polyester derivatives, polycarbonate derivatives, polyester derivatives. , Polyvinyl acetate derivatives, polyurethane derivatives, polysulfone derivatives, acrylate resins, acrylic resins, epoxy resins, and the like.

  The gate insulating film 3 is not limited to a single layer film, and may be a multilayer film. When the gate insulating film 3 is a multilayer film, for example, the surface (the surface on which the self-assembled film 4 is formed) may be covered with an insulating metal oxide.

  The gate insulating film 3 may be formed so as to cover the entire gate electrode 2, for example. At this time, the gate insulating film 3 may be formed on the entire surface of the insulating substrate 1, for example.

  Next, the self-assembled film 4 is formed on the surface (exposed surface) of the gate insulating film 3. The self-assembled film 4 is an insulating film for increasing the alignment accuracy between the source electrode 5 and the drain electrode 6 to be formed in the subsequent process and the gate electrode 2 that has already been formed. And in the manufacturing method of the semiconductor device of Example 1, the self-assembled film 4 is formed using a photosensitive silane coupling agent.

  The photosensitive silane coupling agent used in the semiconductor device of Example 1 is an organosilicon compound that reacts represented by the following reaction formula 1 when irradiated with light of a predetermined wavelength.

In Reaction Scheme 1, A ¹ is a group exhibiting hydrophobicity, and A ³ is a group exhibiting hydrophilicity. In Reaction Formula 1, A ² is a chain group composed of a methylene group (—CH ₂ —) or the like. Also, the group A ² in the left side of the group A ² and the right side in Scheme 1, may be a structure or a part of the atoms or atomic groups are different.

That is, the self-assembled film 4 in the semiconductor device of Example 1 is exposed to light and exposed to light, so that the end of the group A opposite to the side bonded to the methylene group is hydrophobic. It is formed with a photosensitive silane coupling agent that changes from group A ¹ to group A ³ that exhibits hydrophilicity.

  When the self-assembled film 4 is formed using the photosensitive silane coupling agent, first, as shown in FIG. 2C, for example, the entire surface of the gate insulating film 3 is not exposed to light. A self-assembled film 4 ′ made of a silane coupling agent is formed. Hereinafter, the self-assembled film 4 ′ that is not entirely exposed is referred to as an unexposed film 4 ′. In the method for forming the organic TFT of Example 1, the unexposed film 4 ′ is an insulating substrate in which up to the gate insulating film 3 is formed in a solution obtained by dissolving a photosensitive silane coupling agent and an organic acid in an organic solvent such as toluene. 1 is formed.

  Specific examples of the photosensitive silane coupling agent, organic acid, and organic solvent that can be used for forming the unexposed film 4 'in the method for forming the organic TFT of Example 1, conditions at the time of formation, and the like will be described later.

The unexposed film 4 ′ formed using the above solution is a monomolecular film, and each molecule (photosensitive silane coupling agent) is, for example, in the first state J1 shown in FIG. The silicon atom is bonded to any one of the three states of the second state J2 and the third state J3. At this time, each molecule is in a state of standing with respect to the interface between the gate insulating film 3 and the unexposed film 4 ′, and in the vicinity of the surface of the unexposed film 4 ′ (surface on which the source electrode 5 and the like are formed). Are lined with hydrophobic groups A ^{1 at} the end of each molecule. Therefore, in the unexposed film 4 ′ formed using the above solution, both the surface of the first region 4a and the surface of the second region 4b exhibit water repellency (hydrophobicity).

  Therefore, next, the unexposed film 4 ′ is exposed to change the surface of the second region 4 b from hydrophobic to hydrophilic. For example, as shown in FIG. 2E, the unexposed film 4 ′ is exposed to light 9 from the back surface of the insulating substrate 1, in other words, from the surface opposite to the surface on which the gate electrode 2 and the like are formed. And do it.

  At this time, since the gate electrode 2 is a light-shielding conductive film, light does not strike the first region 4 a of the unexposed film 4 ′ that overlaps the gate electrode 2. For this reason, the molecules in the first region 4a of the unexposed film 4 'are not exposed to light. Accordingly, the surface of the first region 4a in the unexposed film 4 'is maintained to be water repellent (hydrophobic) even after being irradiated with light.

On the other hand, since the second region 4b of the unexposed film 4 ′ is exposed to light, the molecules in the second region 4a are exposed to light and react as shown in the reaction formula 1. In this case, the molecules in the second region 4b, the hydrophobic group A ¹ in the vicinity of the surface changes based on A ³ hydrophilic. Therefore, the surface of the second region 4b in the unexposed film 4 ′ is changed from water repellency (hydrophobic) to hydrophilic when irradiated with light.

  When the self-assembled film 4 in which the surface of the first region 4a exhibits water repellency and the surface of the second region 4b exhibits hydrophilicity is formed by the above procedure, then, for example, in FIG. As shown, a source electrode 5 and a drain electrode 6 are formed on the surface of the self-assembled film 4. The electrode 6 is formed on the source electrode 5 and the drain by, for example, printing an ink made of a gold nanoparticle solution by an inkjet printing method, and then heating at 200 ° C. for 5 minutes. At this time, for example, when water, a solvent for a photosensitive composition such as methyl amyl ketone, or toluene was used as a solvent for dissolving the gold nano-particles, printing (coating) was performed on the self-assembled film 4. The solution aggregates on the second region 4b showing hydrophilicity. That is, by forming the source electrode 5 and the drain electrode 6 on the self-assembled film 4 using a liquid conductive material, the gate electrode 2, the source electrode 5, and the drain electrode 6 are self-aligned. Can be aligned.

  At this time, the boundary between the first region 4 a and the second region 4 b of the self-assembled film 4 substantially coincides with the end portion of the gate electrode 2. Therefore, the positional deviation ΔSG between the source electrode 5 and the gate electrode 2 and the positional deviation ΔDG between the drain electrode 6 and the gate electrode 2 can be set to 1 μm or less, for example.

  The source electrode 5 and the drain electrode 6 are not limited to the formation method using the ink jet printing method, but may be other formation methods such as a formation method using a micro-dispensing method, a dip method, a spin coating method, a transfer method, or the like. It may be formed.

  Further, since the source electrode 5 and the drain electrode 6 may be conductive films, they are not limited to gold and may be formed of other metals, conductive metal oxides, conductive polymers, and the like.

  Next, as shown in FIG. 2G, for example, wirings 801, 802, and 803 are formed. The wirings 801, 802, 803 and the like are formed by, for example, ink-jet printing using ink made of a gold nanoparticle solution and then heating at 200 ° C. for 5 minutes.

  Note that the wirings 801, 802, 803 and the like are not limited to the formation method using the ink jet printing method, and other formation methods such as a formation method using a micro-dispensing method, a dip method, a spin coating method, and a transfer method. It may be formed.

  The wirings 801, 802, 803 and the like are not limited to gold, and may be formed using another metal, a conductive metal oxide, a conductive polymer, or the like as long as it is a conductive film.

  Next, for example, as shown in FIG. 1, an organic semiconductor film 7 connected to the source electrode 5 and the drain electrode 6 is formed on the first region 4 a of the self-assembled film 4. The organic semiconductor film 7 is, for example, printed with an ink made of 5% chloroform solution of Poly (3-hexylthiophene-2,5-diyl) Regioregular, which is one of the organic semiconductors, by ink jet printing method at 180 ° C. for 2 minutes. Form by heating.

  The organic semiconductor film 7 may be an organic compound film exhibiting semiconducting electrical characteristics, and is not limited to the above-described compounds. For example, polyacene derivatives such as pentacene and rubrene, polythiophene derivatives, and polyethylene vinylene derivatives. , Polypyrrole derivatives, polyisothianaphthene derivatives, polyaniline derivatives, polyacetylene derivatives, polydiacetylene derivatives, polyazulene derivatives, polypyrene derivatives, polycarbazole derivatives, polyselenophene derivatives, polybenzofuran derivatives, polyphenylene derivatives, polyindole derivatives, polypyridazine derivatives, It is formed of an organic semiconductor material such as a metal phthalocyanine derivative, a fullerene derivative, or a polymer or oligomer containing two or more of these repeating units. In addition, the organic semiconductor film 7 may be a film formed by using the above-described organic semiconductor material, for example, if necessary. The organic semiconductor film 7 may be a single layer film or a multilayer film.

  The outline of the method for forming the organic TFT of Example 1 is as described above. Next, a method for forming the self-assembled film 4 which is a main feature in the method for forming the organic TFT of Example 1 will be described.

  Forming the self-assembled film 4 made of a photosensitive silane coupling agent on the gate insulating film 3 is a method for increasing the alignment accuracy between the gate electrode 2 and the source and drain electrodes 5 and 6. As a matter of fact, studies have already begun.

  In the conventional method of forming the self-assembled film 4 using the photosensitive silane coupling agent, first, for example, the gate insulating film 3 is formed in a solution obtained by dissolving the photosensitive silane coupling agent in an organic solvent such as toluene. The exposed insulating substrate 1 is soaked to form an unexposed film 4 ′ made of a photosensitive silane coupling agent that is not exposed to light.

  However, in the conventional method of forming the unexposed film 4 ′, it is necessary to immerse the insulating substrate 1 on which the gate insulating film 3 is formed in a solution heated to, for example, about 100 ° C. for several hours to half a day. It was. Therefore, during or after the formation of the monomolecular film, for example, deformation of the insulating substrate 1 and peeling of the gate insulating film 3 and the gate electrode 2 are likely to occur. Further, since the formation time of the unexposed film 4 ′ is long, the time required for manufacturing the semiconductor device becomes long.

  As described above, in the conventional method of forming the self-assembled film 4 using the photosensitive silane coupling agent, the insulating substrate 1 is easily deformed, the gate electrode 2 and the gate insulating film 3 are easily peeled off, and the time required for the production. This is a problem that prevents the mass production of semiconductor devices having organic TFTs.

  And as a result of examining the method of shortening the formation time of the self-assembled film 4 made of a photosensitive silane coupling agent, the present inventors have dissolved the photosensitive silane coupling agent in an organic solvent as described above. It has been found that an organic acid may be added to the solution.

When an organic acid is added to a solution obtained by dissolving a photosensitive silane coupling agent in toluene, a methoxy group (—OCH ₃ ) bonded to a silicon atom is replaced with a hydroxyl group (—OH). At this time, for example, three kinds of photosensitive silane coupling agents represented by the following structural formulas 2 to 4 exist in the solution to which the organic acid is added.

  In addition, the abundance ratio of the three types of photosensitive silane coupling agents in the solution to which the organic acid is added varies depending on, for example, the type and amount of the organic acid. However, the inventors of the present application have examined the type and amount of the organic acid, and in any case, the abundance ratio of the photosensitive silane coupling agent represented by the structural formula 2 is the structural formula 3 or the structure. It was confirmed that it was smaller than the abundance ratio of the photosensitive silane coupling agent represented by Formula 4.

  Furthermore, depending on the type and amount of the organic acid, a photosensitive silane coupling agent having a structure such as the left side of Reaction Formula 1 may remain in the solution to which the organic acid has been added. However, when the inventors of the present application examined the type and addition amount of the organic acid, the abundance ratio of the photosensitive silane coupling agent having the structure as shown on the left side of the reaction formula 1 is very small. It was confirmed.

  When the unexposed film 4 ′ is formed using a solution in which the photosensitive silane coupling agent is dissolved, the molecules (photosensitive silane coupling agent) constituting the unexposed film 4 ′ are, for example, as shown in FIG. Bonding with the silicon atom of the gate insulating film 3 in any one of the three states shown in d).

  At this time, the photosensitive silane coupling agent represented by Structural Formula 2 to Structural Formula 4 cuts the O—H bond of the hydroxyl group bonded to the silicon molecule and the O—C bond of the methoxy group, thereby insulating the gate. Bonds to silicon atoms of the film 3.

  In contrast, the photosensitive silane coupling agent represented by the left side of Reaction Formula 1 breaks the O—C bond of the methoxy group and bonds to the silicon atom of the gate insulating film 3.

  The bond energy of the O—H bond is lower than the bond energy of the O—C bond. Therefore, if the insulating substrate 1 on which the gate insulating film 3 is formed is immersed in a solution in which the photosensitive silane coupling agent represented by the structural formulas 2 to 3 is dissolved, the unexposed film 4 ′ can be obtained in a short time. Can be formed.

  Accordingly, the inventors of the present application prepared an organic acid as an organic acid in a solution obtained by dissolving a photosensitive silane coupling agent (5-methoxy-2-nitro-benzyl 4- (trimethoxysilyl) butanesulfonate) represented by the following structural formula 5 in toluene. Acetic acid was added, and an unexposed film 4 ′ was formed using the solution.

Incidentally, ^{A 1} and ^{A 2} in the structural formula 5 are each ^{A 1} and ^{A 2} in the left side of the structural formula of Scheme 1.

  After dissolving 0.2 w% of acetic acid as an organic acid in a solution in which 0.1 wt% of the photosensitive silane coupling agent represented by the structural formula 5 is dissolved in toluene, the gate insulating film 3 is formed in the solution. When the exposed insulating substrate 1 is immersed to form the unexposed film 4 ′, the unexposed film 4 ′ is formed on the entire surface of the gate insulating film 3 even if the insulating substrate 1 is immersed for about 5 minutes. It was confirmed that At this time, it was confirmed that the surface of the formed unexposed film 4 ′ (surface on which the source electrode 5 and the like are formed) has a water contact angle of 95 degrees and exhibits water repellency (hydrophobicity).

  The photosensitive silane coupling agent represented by Structural Formula 5 reacts as shown in the following Reaction Formula 2 when irradiated with light having a wavelength of 350 nm, for example. Therefore, for example, when the monomolecular film is irradiated with light by a method as shown in FIG. 2E and only the molecules in the second region 4b are exposed, the second region after the light irradiation is obtained. The surface of 4b has a contact angle of water of about 40 degrees, and it was confirmed that the surface was changed to a hydrophilic state.

  Therefore, a monomolecular film formed using a photosensitive silane coupling agent represented by Structural Formula 5 and a solution obtained by dissolving an organic acid in an organic solvent can be used as the self-assembled film 4.

  The organic acid added to the solution in which the photosensitive silane coupling agent is dissolved is not limited to acetic acid, but may be other hydrocarbon acids such as formic acid and tetrazole.

In addition, the photosensitive silane coupling agent used for forming the self-assembled film 4 is not limited to the structure represented by the structural formula 5, but may be any structure that reacts as shown in the reaction formula 1 when irradiated with light. Other structures may be used. Regarding the structure of the photosensitive silane coupling agent in which the hydrophobic group A ¹ changes to the hydrophilic group A ³ when irradiated with light, and a method of exposing the photosensitive silane coupling agent, see, for example, JP-A-2003-321479. It is described in detail.

  Further, the photosensitive silane coupling agent used for forming the self-assembled film 4 does not have to be a methoxy group bonded to a silicon atom, and may be another alkoxy group.

  As described above, the method for forming the organic TFT of Example 1 significantly reduces the time required for forming the self-assembled film 4 made of the photosensitive silane coupling agent as compared with the time required for the conventional forming method. be able to.

  In addition, the method for forming the self-assembled film 4 described in Example 1 is performed in a short time even when the temperature of the solution in which the photosensitive silane coupling agent and the organic acid are dissolved is room temperature (for example, about 20 ° C.). A self-assembled film 4 can be formed. Therefore, for example, deformation of the insulating substrate 1 and peeling of the gate electrode 2 and the gate insulating film 3 are less likely to occur.

  In addition, the inventors of the present application did not add an organic acid to the toluene solution of the photosensitive coupling agent represented by Structural Formula 5 for comparison with the method of forming the unexposed film 4 ′ of Example 1. An unexposed film 4 ′ was formed on the surface. At this time, when the temperature of the solution was set to room temperature and the insulating substrate 1 was immersed for 2 hours, a film made of a photosensitive coupling agent was formed on the surface of the gate insulating film 3. However, the obtained film had a water contact angle of about 30 degrees and could not be used as the self-assembled film 4.

  Furthermore, for comparison with the method of forming the unexposed film 4 ′ of Example 1, the inventors of the present application replaced the organic acid in place with the toluene solution of the photosensitive coupling agent represented by Structural Formula 5. I tried adding hydrochloric acid. However, the added hydrochloric acid did not dissolve in the toluene solution and was separated, and a monomolecular film equivalent to the unexposed film 4 ′ could not be formed under the same conditions as the forming method of Example 1.

  When the self-assembled film 4 made of a photosensitive silane coupling agent is formed, the surface of the second region 4b is made water repellent by irradiating only the second region 4b with light as described above. It can be changed to hydrophilic. However, after the exposure, for example, when a surface treatment is performed using a rinse liquid such as a tetramethylammonium hydroxide solution, the contact angle of water on the surface of the second region 4b can be further reduced. The affinity of can be increased.

After forming the self-assembled film 4 by the above procedure using the photosensitive silane coupling agent represented by the structural formula 5, for example, when immersed in a tetramethylammonium hydroxide solution, the molecules in the second region 4b Reacts as shown in Reaction Formula 3 below, and the group A ³ on the surface side changes to the group A ⁴ .

  After forming the self-assembled film 4 by the above procedure using the photosensitive silane coupling agent represented by the structural formula 5, for example, after immersing in a tetramethylammonium hydroxide solution for 1 minute, washing with water, The contact angle of water on the surface of the second region 4b was about 20 degrees. Thus, the self-assembled film 4 formed by the method of Example 1 can enhance the hydrophilicity of the surface of the second region 4b by performing the surface treatment using the rinse liquid.

  Of course, the surface treatment using the rinse liquid as described above is also effective when a photosensitive coupling agent having a structure other than the structure represented by the structural formula 6 is used.

  The rinsing liquid used for the surface treatment is not limited to the above tetramethylammonium hydroxide solution, but other solutions, for example, 2 w% to 25 w% aqueous solution of an ammonium hydroxide compound such as tetrabutylammonium hydroxide, preferably 2 w % To 5w% aqueous solution.

  Next, an example of the relationship between the material and characteristics used when forming the organic TFT by the above procedure will be briefly described.

  The inventors of the present application, for example, have a gate width of about 20 μm, a thickness of the gate insulating film 3 of about 100 nm, a thickness of the source electrode 5 and the drain electrode 6 of about 5 μm, and an organic semiconductor. An organic TFT having a film thickness of about 5 μm (hereinafter referred to as a prototype organic TFT) was formed.

  In forming the prototype organic TFT, polycarbonate, which is an organic compound, was used for the insulating substrate 1. The gate electrode 2, the source electrode 5, and the drain electrode 6 were each formed by printing a solution in which gold nanoparticles were dispersed in a toluene solution by an inkjet printing method and heating at 200 ° C. for 5 minutes. The gate insulating film 3 was formed by printing a poly (methyl silsesquioxane) 10 w% methyl isobutyl ketone solution by inkjet printing and heating at 150 ° C. for 20 minutes.

  In addition, the unexposed film 4 ′ is formed by adding 0.2 w to a 0.1 w% toluene solution of a photosensitive silane coupling agent (5-methoxy-2-nitro-benzyl 4- (trimethoxysilyl) butanesulfonate) represented by the structural formula 5. % Acetic acid was added, the insulating substrate 1 was soaked for 5 minutes, rinsed with toluene, dried, and then heated (fired) at 110 ° C. for 2 minutes. The unexposed film 4 ′ was exposed by irradiating light from the back surface of the insulating substrate 1 using a high pressure mercury lamp for 20 minutes. Further, after the unexposed film 4 ′ was exposed to form the self-assembled film 4, it was immersed in a 2.38 w% aqueous solution of tetramethylammonium hydroxide for 1 minute and then washed with deionized running water for 2 minutes.

  The organic semiconductor film 7 was formed by printing ink made of 5% solution of Poly (3-hexylthiophene-2,5-diyl) Regioregular in chloroform by an ink jet printing method and heating at 180 ° C. for 2 minutes.

At this time, the positional deviation ΔSG between the source electrode 5 and the gate electrode 2 and the positional deviation ΔDG between the drain electrode 6 and the gate electrode 2 in the formed prototype organic TFT were about 0.5 μm, respectively. Further, when the mobility of the prototype organic TFT was examined, it was 0.085 cm ² / Vs. This value is a characteristic of the organic TFT that is considered not to be misaligned between the gate electrode 2 and the source electrode 5 and the drain electrode 6.

The inventors of the present application changed the insulating substrate 1 from a polycarbonate substrate to a glass substrate to form the prototype organic TFT. As a result, the mobility of the prototype organic TFT was 0.11 cm ² / Vs.

In addition, when the conductive organic material used for forming the conductive film such as the gate electrode 2 is changed from the gold nanoparticle to the silver nanoparticle, the above-mentioned prototype organic TFT is formed. The degree was 0.077 cm ² / Vs. In addition, the mobility of the prototype organic TFT when using platinum nanoparticles as the conductive material is 0.1 cm ² / Vs, and the mobility of the prototype organic TFT when using copper nanoparticles is 0.08 cm. ² / Vs. Furthermore, the mobility of the prototype organic TFT when using PEDOT doped with a conductive polymer was 0.08 cm ² / Vs. In this way, although there are differences due to the difference in work function of conductive materials, in any case, the characteristics are equivalent to those formed using gold nanoparticles, and the deviation from the characteristics specified in the design data Is very small.

  However, in view of performance, ease of synthesis, storage stability, and the like, the conductive material used when forming the conductive film such as the gate electrode 2 is preferably gold nanoparticle.

  Further, in the self-assembled film 4 in the prototype organic TFT, the contact angle of water on the surface of the first region 4a is 95 degrees, and the contact angle of water on the surface of the second region 4b is 20 degrees. It was.

  Further, 0.2 w% of an organic acid added to a 0.1 w% toluene solution of a photosensitive silane coupling agent (5-methoxy-2-nitro-benzyl 4- (trimethoxysilyl) butanesulfonate) represented by Structural Formula 5 is used. When the unexposed film 4 ′ was formed in place of formic acid, the contact angle of water on the surface of the unexposed film 4 ′ was 95.5 degrees. Further, when the unexposed film 4 ′ was formed by changing the organic acid to 0.2 w% tetrazole, the contact angle of water on the surface of the unexposed film 4 ′ was 95.2 degrees. Thus, even if the kind of the organic acid added to the solution of the photosensitive silane coupling agent is changed, the surface of the unexposed film 4 ′ exhibits water repellency (hydrophobicity).

  Further, when the photosensitive silane coupling agent and the solvent for dissolving the organic acid were changed to xylene to form an unexposed film 4 ', the contact angle of the surface of the unexposed film 4' was 95 degrees. Further, when the solvent for dissolving the photosensitive silane coupling agent and the organic acid was changed to tetrahydrofuran to form the unexposed film 4 ', the contact angle of the surface of the unexposed film 4' was 94.9 degrees. Thus, even if the type of the photosensitive silane coupling agent and the organic solvent dissolving the organic acid is changed, the surface of the unexposed film 4 ′ exhibits water repellency (hydrophobicity).

In addition, when an organic semiconductor material used for forming the organic semiconductor film 7 is replaced with, for example, a polyaniline solution doped with an emeraldine salt, a prototype organic TFT is formed. The mobility of the prototype organic TFT is 0.05 cm ² / Vs. Met. Thus, the prototype organic TFT formed by the method of Example 1 can obtain sufficient characteristics even when the organic semiconductor material used for forming the organic semiconductor film 7 is changed.

The organic semiconductor material used for forming the organic semiconductor film 7 is a 1.3 wt% aqueous solution of, for example, Poly (styrenesulfonate) / poly (s, 3-digydrothieno- [3,4-b] -1,4, dioxin). When a prototype organic TFT was formed using, the mobility of the prototype organic TFT was 0.078 cm ² / Vs. Also in this case, the organic TFT can obtain sufficient characteristics. Further, when the organic semiconductor film 7 is formed using the above aqueous solution, it is slightly advantageous in terms of cost compared to the case where it is formed with other materials.

Moreover, when the organic semiconductor film 7 was formed using pentacene using a vapor deposition method, the mobility of the prototype organic TFT was 0.09 cm ² / Vs. In this case, although it is not a printing method, there was no great difference in cost because of partial replacement.

In addition, when the material used for forming the gate insulating film 3 is changed to, for example, a 0.5% xylene solution of epoxidized polybutadiene, a prototype organic TFT is formed. The mobility of the prototype organic TFT is 0.09 cm ² / Vs. Met. As described above, the prototype organic TFT formed by the method of Example 1 can obtain sufficient characteristics even if the material used for forming the gate insulating film 3 is changed.

Further, when the material used for forming the gate insulating film 3 is changed to, for example, a 2% methyl amyl ketone solution of polyhydroxystyrene to form a prototype organic TFT, the mobility of the prototype organic TFT is 0.07 cm ² / Vs. Met. In addition, polyhydroxystyrene is inexpensive and has an advantage that methyl amyl ketone as a safety solvent can be used.

In addition, when a prototype organic TFT was formed by replacing the material used for forming the gate insulating film 3 with, for example, a 3% methyl amyl ketone solution of polyimide, the mobility of the prototype organic TFT was 0.07 cm ² / Vs. It was. Note that when the gate insulating film 3 is formed using the above-described solution, the transmittance is slightly lower than when the gate insulating film 3 is formed using other materials, and thus the exposure time of the unexposed film 4 ′ increases.

  When the gate insulating film 3 is formed using the insulating organic polymer compound as described above, for example, a siloxane compound film is formed on the surface of the gate insulating film 3 in order to form the self-assembled film 4. It is necessary to form a silazane compound film. For this reason, the number of steps for forming the organic TFT increases, and the manufacturing cost of the semiconductor device slightly increases.

  As described above, according to the method for manufacturing a semiconductor device of Example 1, an organic TFT with extremely small positional deviation of electrodes can be easily formed in a short time. Therefore, it is possible to reduce deterioration of the characteristics of the organic TFT and variation in characteristics among the plurality of organic TFTs in the semiconductor device having the organic TFT.

  In addition, according to the method for manufacturing the semiconductor device of Example 1, the formation time of the self-assembled film 4 of the organic TFT can be significantly shortened, and the temperature at the time of formation can be lowered. Therefore, deformation of the insulating substrate 1 and peeling of the gate electrode 2 and the gate insulating film 3 can be prevented, and the manufacturing yield of a semiconductor device having an organic TFT is improved.

  In addition, the organic TFT formation method of Example 1 is that the gate electrode 2, the gate insulating film 3, the source electrode 5 and the drain electrode 6, the wirings 801, 802, 803, and the organic semiconductor film 7 are formed by a printing method, respectively. ing. Therefore, there is no process for forming an etching resist using a photolithography technique, a process for forming a through hole, and the like, and the manufacturing cost of the semiconductor device can be greatly reduced.

  Furthermore, in the method for forming the organic TFT of Example 1, all the steps can be performed at a low temperature (for example, 200 ° C. or lower). Therefore, the insulating substrate 1 can be a flexible substrate such as plastic and made of a thermoplastic material that can be deformed by heat. Therefore, the manufacturing method of the semiconductor device of Example 1 is suitable for a manufacturing method of a flexible display such as electronic paper using a sheet-like plastic substrate.

  Further, in the method of manufacturing the semiconductor device of Example 1, when the unexposed film 4 ′ is formed, a solution in which molecules (photosensitive silane coupling agents) having structures such as structural formulas 2 to 3 are dissolved. It forms using. With respect to the unexposed film 4 ′ formed using such a solution, the inventors of the present application are bonded in the first state J1 shown in FIG. 2D by, for example, infrared spectroscopy. When the number of molecules, the number of molecules bound in the second state J2 and the number of molecules bound in the third state J3 were estimated, the number of molecules bound in the first state J1 or the second state J2 The ratio of the number of molecules bound to the number of molecules bound in the third state J3 was approximately 2 to 8.

  On the other hand, regarding the self-assembled film formed by a conventional method in which no organic acid is added, the inventors of the present application use the infrared spectroscopic analysis or the like to determine the number of molecules bonded in the first state J1, the second When the number of molecules bonded in the state J2 and the number of molecules bonded in the third state J3 were estimated, the number of molecules bonded in the first state J1 and the second state The ratio to the number of molecules bound in J2 or the third state J3 was approximately 9: 1.

  In the molecule bonded in the first state J1, only one oxygen atom of the three oxygen atoms bonded to the silicon atom is bonded to the silicon atom of the gate insulating film 3. Therefore, the molecule bonded in the first state J1 has a weaker binding force with the gate insulating film 3 than the molecule bonded in the second state J2 or the third state J3, and the gate insulating film Easy to leave from 3. Therefore, as in the prior art, when most of the molecules constituting the self-assembled film 4 are molecules bonded in the first state J1, the self-assembled film 4 is easily peeled off from the gate insulating film 3.

  That is, by applying the method for forming the unexposed film 4 ′ of Example 1, the semiconductor device of Example 1 has high adhesion between the self-assembled film 4 and the gate insulating film 3. 4 becomes difficult to peel off.

  FIG. 3 is a schematic circuit diagram for explaining an example of a circuit configuration of a semiconductor device manufactured by the method of manufacturing a semiconductor device according to the second embodiment of the present invention.

  In Example 2, an example of a method for manufacturing a semiconductor device to which the organic TFT forming method described in Example 1 is applied will be described. In the second embodiment, in order to simplify the description, a method for manufacturing a semiconductor device having nine organic TFTs arranged in a matrix as shown in FIG. 3 will be described as an example.

  The semiconductor device described in Example 2 includes nine organic TFTs arranged in a matrix of three in the horizontal direction and three in the vertical direction, three first signal lines 10, and three second signals. And a signal line 11. At this time, the three organic TFTs arranged in the horizontal direction have gates connected to the common first signal line 10. In addition, the drains of the three organic TFTs arranged in the vertical direction are connected to the second signal line 11 having a common drain. The source of each organic TFT is connected to, for example, another organic TFT or another element formed in the semiconductor device. In Example 2, the source electrode of the organic TFT element is used as a terminal. deal with.

  When the circuit shown in FIG. 3 is formed on the surface of the insulating substrate 1 by the method described in the first embodiment, it can be formed by, for example, an organic TFT having a configuration as shown in FIG. However, when manufacturing a semiconductor device having a plurality of organic TFTs, as described in Example 1, it is inefficient to form the gate electrode 2 and the gate insulating film 3 of each organic TFT individually. This can cause productivity to decrease.

  Therefore, in Example 2, in order to efficiently manufacture a semiconductor device having a plurality of organic TFTs, a circuit is formed on the surface of the insulating substrate 1 by the following method.

4A to 4G are schematic views for explaining a method for forming an organic TFT in the method for manufacturing a semiconductor device according to the second embodiment.
FIG. 4A is a schematic plan view for explaining the step of forming the gate electrode. FIG. 4B is a schematic plan view for explaining a process of forming the gate insulating film and the self-assembled film. FIG. 4C is a schematic plan view for explaining a process of forming the source electrode and the drain electrode. FIG. 4D is a schematic cross-sectional view for explaining an example of a cross-sectional configuration taken along line L2-L2 ′ in FIG. FIG. 4E is a schematic plan view for explaining the step of forming the organic semiconductor film. FIG. 4F is a schematic plan view for explaining the process of forming the protective film. FIG. 4G is a schematic cross-sectional view showing an example of a cross-sectional configuration taken along line L3-L3 ′ in FIG.

  In the method for forming an organic TFT in the method of manufacturing a semiconductor device of Example 2, first, as shown in FIG. 4A, the first signal line 10 made of a light-shielding conductive film is formed on the surface of the insulating substrate 1 and The light shielding member 12 is formed.

  At this time, the gate electrode 2 of the organic TFT is integrally formed with the first signal line 10, and the region surrounded by the two-dot difference line in FIG. 4A corresponds to the gate electrode 2 of each organic TFT. .

  The first signal line 10 has a notch 10a and a first opening 10b in a region intersecting with the second signal line 11 formed in a later step, and the first signal line 10 is formed in a region where the source electrode 5 is formed. The shape has two openings 10c.

  Further, the light shielding member 12 has a shape in which a region for forming the terminal portion of the second signal line 11 is greatly opened.

  At this time, the gap W1 between the adjacent first signal lines 10 and the distance W2 between the notch 10a and the first opening 10b should be smaller than the width W3 of the notch 10a and the first opening 10b. Is desirable.

  Next, as shown in FIG. 4B, the gate insulating film 3 covering the entire first signal line 10 and the light shielding member 12 is formed, and the self-assembled film 4 is formed on the surface of the gate insulating film 3. To do. The gate insulating film 3 is an insulating film having high translucency, and is formed of, for example, an insulating organic polymer or an insulating inorganic compound. The self-assembled film 4 is formed by the method described in the first embodiment. At this time, in the self-assembled film 4, the surface of the region where the parallel oblique lines in FIG. 4B are drawn shows hydrophilicity, and the surface of the other region shows water repellency (hydrophobicity).

  Next, as shown in FIG. 4C, the source electrode 5 and the second signal line 11 are formed. The source electrode 5 and the second signal line 11 are formed by, for example, ink-jet printing, printing ink made of a solution in which gold nanoparticles are dissolved, and then heating at 200 ° C. for 5 minutes.

  At this time, the drain electrode 6 of the organic TFT is integrally formed with the second signal line 11, and a portion of the second signal line 11 facing the source electrode 5 functions as the drain electrode 6.

  By the way, a portion where the second signal line 11 and the first signal line 10 intersect has a cross-sectional configuration as shown in FIG. At this time, in the self-assembled film 4, the surface of the first region 4a that overlaps the first signal line 10 is water-repellent, and the surface of the second region 4b that overlaps the notch 10a and the first opening 10b. Is hydrophilic. Therefore, if the distance W2 between the notch 10a and the first opening 10b is large, the ink printed on the first region 4a flows to the second region 4b when the ink is printed, and the second region 4b. The signal line 11 may be disconnected. Conversely, if the distance W2 between the notch 10a and the first opening 10b is small, for example, the ink can be left on the first region 4a due to the surface tension of the printed ink. Therefore, when forming the first signal line 10, it is desirable to make the distance W2 between the notch 10a and the first opening 10b as small as possible.

  In addition, if the gap W1 between two adjacent first signal lines 10 is large, for example, when the amount of printed ink is too large, a part of the ink is above the gap between the first signal lines 10. And the two adjacent second signal lines 11 may be short-circuited. For this reason, when forming the first signal line 10, it is desirable to make the gap W1 between the two adjacent first signal lines 10 as small as possible.

  In the method of forming the organic TFT of Example 2, the dimension of the terminal portion 11t of the second signal line 11 is set to the width W3 of the notch 10a of the first signal line 10, that is, the width of the second signal line 11. It is desirable to make it larger. In this way, when the amount of printed ink is large, an excessive amount of the portion forming the second signal line 11 flows into the terminal portion 11t having a large size, and when it is small, the portion of the terminal portion 11t having a large size is formed. Ink flows out to a portion where the second signal line 11 is formed. Therefore, even if the amount of ink to be printed varies, it is possible to reduce the film thickness deviation of the second signal line 11.

  Next, as shown in FIG. 4E, an organic semiconductor film 7 is formed.

  Thereafter, as shown in FIGS. 4F and 4G, contact holes 14 are formed on the first signal line 10, the second signal line 11, and the source electrode 5, respectively. A protective film 13 is formed. Various methods for forming the protective film 13 having the contact hole 14 are conventionally known, and any one of them may be used in the method for manufacturing the semiconductor device of the second embodiment.

  Although a description of a specific example is omitted, a circuit that performs a predetermined operation can be formed by forming a wiring or an insulating film on the protective film 13 thereafter.

  As described above, when the first signal line 10 and the gate electrode 2 are integrally formed, and the second signal line 11 and the drain electrode 6 are integrally formed, the organic TFT having the configuration described in the first embodiment is formed in a matrix. A semiconductor device can be manufactured more efficiently than in the case of forming an arranged circuit.

  The inventors of the present invention manufactured a semiconductor device in which organic TFTs are arranged in a matrix by the above procedure, and measured the characteristics (for example, mobility) of each organic TFT. It was confirmed.

  As described above, according to the method for manufacturing the semiconductor device of the second embodiment, it is possible to reduce the deterioration of the characteristics of the organic TFT and the dispersion of characteristics among the plurality of organic TFTs.

  In addition, according to the method for manufacturing a semiconductor device of Example 2, a circuit in which a plurality of organic TFTs are arranged in a matrix can be efficiently formed.

  The present invention has been specifically described above based on the above-described embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. is there.

  For example, in Example 1, a bottom gate type organic TFT in which a gate electrode 2, a gate insulating film 3, and an organic semiconductor film 7 are laminated in this order on an insulating substrate 1 is taken as an example. explained. However, the method for forming the self-assembled film 4 in the method for forming the organic TFT described in Example 1 is not limited to this, and the organic semiconductor film 7, the gate insulating film 3, and the gate electrode 2 are formed on the insulating substrate 1. Can also be applied to a method of forming a top gate type organic TFT which is laminated in this order.

  When forming the top gate type organic TFT, for example, first, the source electrode 5 and the drain electrode 6 are formed on the surface of the insulating substrate 1. Next, the organic semiconductor film 7 is formed. Next, the gate insulating film 3 is formed. Next, the self-assembled film 4 is formed. Next, the gate electrode 2, wirings 801, 802, 803, and the like are formed. At this time, if the self-assembled film 4 is formed by the method described in the first embodiment, the positional deviation between the source electrode 5 and the drain electrode 6 and the gate electrode 2 can be set to 1 μm or less, for example. it can.

  In Example 1 and Example 2, when the self-assembled film 4 is formed, light is irradiated from the back surface of the insulating substrate 1, that is, the surface opposite to the surface on which the gate electrode 2 or the like is formed. The unexposed film 4 ′ is exposed. However, when the unexposed film 4 'is exposed, for example, light can be irradiated from the surface of the insulating substrate 1 on which the gate electrode and the like are formed.

  When the self-assembled film 4 is formed, when exposure is performed by irradiating light from the surface of the insulating substrate 1 on which the gate electrode or the like is formed, for example, a pattern drawing function such as a direct drawing exposure machine is provided. An exposure machine may be used.

  Further, when the unexposed film 4 ′ is exposed by an exposure machine having a pattern drawing function, the degree of freedom in the shape of the hydrophilic region (second region 4 b) in the self-assembled film 4 is increased. For this reason, the self-assembled film 4 is not used for alignment with a conductive film already formed like an electrode of an organic TFT, but when, for example, a wiring connected to a lower conductive film through a through hole is formed. It can also be used to increase the accuracy of alignment and the accuracy of fine wiring dimensions.

FIG. 5A to FIG. 5C are schematic views for explaining one application example of the organic TFT forming method according to the present invention.
FIG. 5A is a schematic plan view and a schematic cross-sectional view for explaining an example of a wiring formed by applying the present invention. FIG. 5B is a schematic perspective view for explaining an example of an exposure method for the self-assembled film. FIG. 5C is a schematic plan view and a schematic cross-sectional view showing an example of a wiring formed by applying the present invention.

  5A and 5C are schematic plan views in which the upper diagram (P) shows an example of the respective planar configurations, and the lower diagram (S) is the upper diagram (P). It is a schematic cross section which shows an example of the cross-sectional structure in line L4-L4 '.

  In this specification, as an example of a wiring forming method to which the organic TFT forming method of the present invention is applied, for example, a forming method of a second wiring connected to a first wiring in a lower layer through a through hole is given.

  At this time, on the surface of the insulating substrate 1, first, as shown in FIG. 5A, for example, the insulating layer 3 having wirings 804 and 805, the through hole 14, and an unexposed film made of a photosensitive silane coupling agent 4 ′ is formed. Note that the dotted line in the upper diagram (P) of FIG. 5A shows the outer shape of the wiring 806 formed on the self-assembled film 4 obtained by exposing the unexposed film 4 ′.

  As described in Example 1, the unexposed film 4 ′ is formed by immersing the insulating substrate 1 on which the insulating layer 3 is formed in a solvent in which a photosensitive silane coupling agent and an organic acid are dissolved. At this time, the photosensitive silane coupling agent is selectively bonded to the surface of the insulating layer 3, for example. Therefore, the wirings 804 and 805 are exposed on the bottom surface of the through hole 14.

  Next, the unexposed film 4 ′ is exposed to form a self-assembled film 4. For example, as shown in FIG. 5B, the exposure of the unexposed film 4 ′ is a region where the wiring 806 is formed using an exposure machine having an optical system 16 that can be moved in the x direction and the y direction. Only 15 is irradiated with light. Then, surface treatment is performed using a rinse solution. In the self-assembled film 4 thus obtained, only the surface of the region 15 where the wiring 806 is formed exhibits hydrophilicity.

  Next, for example, ink formed of a solution in which copper nanoparticles are dissolved is printed on the region 15 where the wiring 806 is formed by an inkjet printing method. At this time, for example, the area where ink is printed may shift. However, if the self-assembled film 4 as described above is formed, even if the printing position of the ink is slightly shifted, the ink is self-aligned in the area 15 (area where the wiring 806 is formed) showing hydrophilicity. Aggregate. Therefore, for example, as shown in FIG. 5C, the wiring 805 and the wiring 806 can be reliably connected.

  Depending on the type of the photosensitive silane coupling agent used to form the unexposed film 4 ′ and the size of the through hole 14, for example, the unexposed film 4 ′ covering the wirings 804 and 805 on the bottom surface of the through hole 14 may be used. Sometimes formed. However, the unexposed film 4 'has a very thin film thickness of about 1.0 nm. Therefore, even when the self-assembled film 4 is interposed between the wiring 805 and the wiring 806, sufficient conductivity can be ensured.

It is the model top view and schematic cross section which show an example of schematic structure of the organic TFT formed by the manufacturing method of the semiconductor device of Example 1 by this invention. It is the model top view and schematic cross section for demonstrating the process of forming a gate electrode. It is the model top view and model cross-sectional view for demonstrating the process of forming a gate insulating film. It is the model top view and schematic cross section for demonstrating the process of forming the monomolecular film of a photosensitive silane coupling agent. It is a schematic diagram which shows an example of the coupling | bonding state of a gate insulating film and a photosensitive silane coupling agent. It is the model top view and schematic cross section for demonstrating an example of the method of exposing a part of monomolecular film. It is the model top view and model sectional drawing for demonstrating the process of forming a source electrode and a drain electrode. It is the model top view and model cross-sectional view for demonstrating the process of forming wiring. It is a schematic circuit diagram for demonstrating an example of the circuit structure of the semiconductor device manufactured by the manufacturing method of the semiconductor device of Example 2 by this invention. It is a schematic plan view for demonstrating the process of forming a gate electrode. It is a schematic plan view for demonstrating the process of forming a gate insulating film and a self-organization film. It is a schematic plan view for demonstrating the process of forming a source electrode and a drain electrode. FIG. 5C is a schematic cross-sectional view for explaining an example of a cross-sectional configuration along line L2-L2 ′ in FIG. It is a schematic plan view for demonstrating the process of forming an organic-semiconductor film. It is a schematic plan view for demonstrating the process of forming a protective film. FIG. 5 is a schematic cross-sectional view illustrating an example of a cross-sectional configuration taken along line L3-L3 ′ in FIG. It is a schematic plan view and a schematic cross-sectional view for explaining an example of wiring formed by applying the present invention. It is a model perspective view for demonstrating an example of the exposure method of a self-organization film | membrane. It is a schematic plan view and a schematic cross-sectional view showing an example of wiring formed by applying the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Insulating substrate 2 ... Gate electrode 3 ... Gate insulating film (insulating layer)
4 ... Self-assembled film 4 '... Unexposed film 5 ... Source electrode 6 ... Drain electrode 7 ... Organic semiconductor film 801, 802, 803, 804, 805, 806 ... Wiring 9 ... Light 10 ... First signal line 11 ... Second signal line 12 ... light shielding member 13 ... protective film 14 ... contact hole (through hole)
15 ... Region for forming wiring 806 16 ... Optical system

Claims (20)

A method of manufacturing a semiconductor device including a step of forming a MISFET on an insulating substrate,
The step of forming the MISFET includes a first step of forming a first conductive layer on the insulating substrate,
A second step of forming a gate insulating film that covers the first conductive layer or intersects the first conductive layer;
A third step of forming a monomolecular film made of a photosensitive silane coupling agent on the gate insulating film;
A fourth step of exposing only a predetermined region of the monomolecular film that does not overlap with the first conductive layer;
A fifth step of forming a second conductive layer on the region of the monomolecular film exposed in the fourth step;
A sixth step of forming a semiconductor layer made of an organic semiconductor, which is performed either after the fifth step or between the first step and the second step,
In the fifth step, the second conductive layer is formed using a solution-like conductive material,
The third step is represented by the following structural formula 1 and is opposite to the one bonded to the methylene group (—CH ₂ —) at the end of A in the following structural formula 1 by exposing it to light. A method of manufacturing a semiconductor device, comprising forming the monomolecular film using a solution in which an organic acid is dissolved in an organic solvent and the silane coupling agent whose end on the side changes from a hydrophobic group to a hydrophilic group .

The sixth step is performed after the fifth step,
In the first step, a gate electrode of the MISFET is formed,
The method of manufacturing a semiconductor device according to claim 1, wherein in the fifth step, a source electrode and a drain electrode of the MISFET are formed. The sixth step is performed between the first step and the second step,
The first step forms a source electrode and a drain electrode of the MISFET,
The method of manufacturing a semiconductor device according to claim 1, wherein the fifth step forms a gate electrode of the MISFET.   In the monomolecular film formed in the third step, the contact angle of water on the surface on which the second conductive layer is formed is 90 degrees or more, and the contact angle of water on the surface when exposed is exposed to light. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the angle changes to 40 degrees or less.   Between the fourth step and the fifth step, there is a seventh step of performing a surface treatment on the surface of the monomolecular film on which the second conductive layer is formed using an organic alkaline aqueous solution. The method of manufacturing a semiconductor device according to claim 1, wherein: The insulating substrate uses a substrate having translucency,
The first conductive layer is formed of a light-shielding conductor,
The insulating layer is formed of a light-transmitting insulator,
In the fourth step, the monomolecular film is irradiated with light from the surface of the insulating substrate opposite to the surface on which the first conductive layer, the insulating layer, and the monomolecular film are formed. The method of manufacturing a semiconductor device according to claim 1, wherein:   2. The method of manufacturing a semiconductor device according to claim 1, wherein the fifth step is performed using any one of an inkjet method, a micro-dispensing method, a casting method, a dipping method, and a transfer method. .   2. The method of manufacturing a semiconductor device according to claim 1, wherein the first step, the second step, the third step, and the fifth step are each performed using a printing method.   The method of manufacturing a semiconductor device according to claim 1, wherein the insulating substrate is a substrate made of a resin.   The method of manufacturing a semiconductor device according to claim 1, wherein the insulating substrate is a substrate made of a silicon compound.   The method for manufacturing a semiconductor device according to claim 1, wherein the insulating substrate is a substrate made of an organic compound.   A semiconductor device manufactured by the method for manufacturing a semiconductor device according to claim 1. A semiconductor device having a plurality of MISFETs provided on an insulating substrate,
The MISFET includes a gate electrode provided on the insulating substrate;
A gate insulating film covering the entire gate electrode or intersecting the gate electrode;
A monomolecular film provided on the gate insulating film;
A source electrode, a drain electrode, and an organic semiconductor layer provided on the monomolecular film;
Each of the molecules constituting the monomolecular film has a silicon atom bonded to a methylene group (—CH ₂ —) at an end on the interface side with the insulating layer, and
The monomolecular film has a first molecule in which a monovalent atom or group is bonded to the silicon atom, and a second molecule in which the monovalent atom or group is not bonded to the silicon atom. And
The semiconductor device, wherein the number of the second molecules is larger than the number of the first molecules. The monomolecular film has a first region that overlaps the source electrode or the drain electrode, and a second region that does not overlap,
Of the molecules constituting the monomolecular film, the molecule in the first region and the molecule in the second region have different terminal groups on the opposite side from the one close to the insulating layer. The semiconductor device according to claim 13. A semiconductor device having a plurality of MISFETs provided on an insulating substrate,
The MISFET includes a source electrode and a drain electrode provided on the insulating substrate,
An organic semiconductor layer covering the source electrode and the drain electrode or intersecting the source electrode and the drain electrode;
A gate insulating film provided on the organic semiconductor layer;
A monomolecular film provided on the gate insulating film;
A gate electrode provided on the monomolecular film,
Each of the molecules constituting the monomolecular film has a silicon atom bonded to a methylene group (—CH ₂ —) at an end on the interface side with the insulating layer, and
The monomolecular film has a first molecule in which a monovalent atom or group is bonded to the silicon atom, and a second molecule in which the monovalent atom or group is not bonded to the silicon atom. And
The semiconductor device, wherein the number of the second molecules is larger than the number of the first molecules. The monomolecular film has a first region that overlaps with the gate electrode and a second region that does not overlap,
Of the molecules constituting the monomolecular film, the molecule in the first region and the molecule in the second region have different terminal groups on the opposite side from the one close to the insulating layer. The semiconductor device according to claim 15.   16. The semiconductor device according to claim 13, wherein the monomolecular film has a ratio of the first molecule to the second molecule of about 2: 8.   16. The monomolecular film according to claim 13, wherein the total number of the monovalent atoms or groups bonded to the silicon atom is smaller than the number of molecules contained in the monomolecular film. A semiconductor device according to 1. The semiconductor device according to claim 13, wherein the first molecule has a methoxy group (—OCH ₃ ) bonded to the silicon atom.   When the surface of the insulating substrate on which the gate electrode is formed is viewed, the gap or overlap amount between the gate electrode and the source electrode, and the gap or overlap amount between the gate electrode and the source electrode, respectively, 16. The semiconductor device according to claim 13, wherein the semiconductor device is 1 μm or less.

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