KR20030093925A - Display device with active-matrix transistor and method for manufacturing the same - Google Patents

Abstract

The amorphous silicon film 104 of the pixel portion of the active matrix substrate 101 constituting the display device is selectively irradiated with a laser beam 208 to be modified into a polysilicon film 105. Then, pixel circuits such as thin film transistors are formed in the modified polysilicon film 105. In this manner, a display device having an active matrix substrate having a high performance thin film transistor circuit can be realized very economically.

Description

Active matrix display device and manufacturing method therefor {DISPLAY DEVICE WITH ACTIVE-MATRIX TRANSISTOR AND METHOD FOR MANUFACTURING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to an active matrix display device in which a film quality of a semiconductor film formed on an insulating substrate is modified by laser light, and an active element is formed of the modified semiconductor film, and a manufacturing method thereof. In addition, below, a display apparatus may be called a display apparatus or simply a display.

As a driving element of a matrix array of pixels, an active matrix display device (or an active matrix display device or display device) using an active element such as a thin film transistor is widely used. As is well known to those skilled in the art, most of this kind of active matrix display devices are of good quality by arranging a plurality of pixel circuits composed of active elements such as thin film transistors formed using a silicon film as a semiconductor film on a substrate. Can be displayed. Here, as the active element, a thin film transistor which is a typical example thereof will be described as an example.

However, in a thin film transistor using an amorphous silicon semiconductor film (hereinafter, referred to simply as a silicon film) that has been generally used as a semiconductor film, the performance of the thin film transistor represented by its mobility is limited, and therefore, It was difficult to construct a circuit requiring high functionality. In order to realize a high mobility thin film transistor necessary to provide better image quality, it is effective to form (crystallize) an amorphous silicon film into a polysilicon film in advance and form a thin film transistor using the crystallized polysilicon film.

In order to improve this modification (crystallization) and this crystallinity, a method of modifying an amorphous silicon film into a polysilicon film by irradiating excimer laser light (or laser beam or simply laser light) is used. Such a method is explained in full detail, for example in Nonpatent Documents 1-3.

A modification method by crystallization of an amorphous silicon film using excimer laser light irradiation will be described with reference to FIG. 26. FIG. 26 is an explanatory view of a crystallization method by scanning the most common excimer pulsed laser light irradiation. FIG. 26A illustrates a structure of a glass substrate on which a semiconductor layer to be irradiated is formed, and FIG. The state modified by irradiation of a laser beam is shown. Although glass and ceramics are used for this board | substrate, it demonstrates here as using a glass board | substrate. Irradiation of the linear excimer laser beam 303 having a width of several mm to several 100 mm on the amorphous silicon film 302 deposited on the glass substrate 301 with the base film (SiN, etc. not shown) interposed therebetween. Then, as indicated by the arrow, scanning is performed to move the irradiation position every one to several pulses along one direction (x direction), thereby converting the amorphous silicon film 302 of the entire substrate 301 into the polysilicon film 304. Reform. The polysilicon film modified by this method is subjected to various processes such as etching, wiring formation, ion implantation, and the like to prepare an active matrix substrate in which a driving thin film transistor circuit is disposed in each pixel portion. This substrate is used to manufacture an active matrix display such as a liquid crystal display or an organic EL.

FIG. 27 is a partial plan view of a laser light irradiation section and a principal part plan view illustrating a configuration example of the thin film transistor section in FIG. 26. As shown in Fig. 27A, many of the crystallized silicon particles having a diameter of about 0.05 µm to 0.5 µm grow uniformly in the plane in the laser light irradiation section. The grain boundary of each silicon particle (namely, silicon crystal) is closed. A portion enclosed by □ in FIG. 27A becomes a transistor portion TRA serving as a semiconductor film of each thin film transistor. Since the modification of the conventional silicon film means such crystallization, it should be emphasized that the contents are different from those of the present invention.

In order to form the pixel circuit using the modified silicon film 304 described above, the transistor of FIG. 27A is used to use a portion of the crystallized silicon as the transistor portion as shown in FIG. 27B. Unnecessary portions other than the portion to be the sub TRA are removed by etching to form portions of the island-shaped silicon film, and a gate insulating film (not shown), a gate electrode (not shown), a source electrode SD1, and a drain are formed on the island PSI. The electrode SD2 is arranged to manufacture a MIS transistor. Techniques for forming such transistors are well known to those skilled in the art. In the prior art, since the modification operation for crystallization is performed on the entire pixel portion, the efficiency of the modification is deteriorated.

[Non-Patent Document 1]

T. C. Angelis et al; Effect of Excimer Laser Annealing on the Structural and Electrical Properties of Polycrystalline Silicon Thin-Film Transistor, J. Appl. Phy., Vol. 86, pp 4600-4606, 1999.

[Non-Patent Document 2]

H. Kuriyama et al; Lateral Grain Growth of Poly-Si Films with a Specific Orientation by an Excimer Laser Annealing Method, Jpn. J. Appl. Phy., Vol. 32, pp 6190-6195, 1993.

[Non-Patent Document 3]

K. Suzuki et al; Correlation between Power Density Fluctuation and Grain Size Distribution of Laser annealed Poly-Crystalline Silicon, SPIE Conference, Vol. 3618, pp 310-319, 1999.

In the above-described prior art, there is an advantage in that an active matrix substrate having a high performance thin film transistor formed by forming a modified silicon film on a substrate can be manufactured. However, the economic cost for modifying the silicon film is high, and the above advantage is fully utilized. I could not have problems. Such a problem arises from the need for using a high-cost excimer laser device, and the time required for modifying the silicon film on the entire surface of the substrate due to the lack of the intensity and the pulse interval of the excimer laser pulse.

This problem becomes remarkable when the display device is to be provided at a low cost by forming multiple substrates for constituting a large display device. In the case of modifying the silicon film by increasing the substrate size, it is not only a very expensive facility. Inadequate throughput can only be achieved, and this problem is hardly acceptable. Therefore, there is a strong demand for the provision of a new technology that can realize modification of the silicon film at a high speed and at high efficiency with inexpensive equipment even for a large sized substrate.

SUMMARY OF THE INVENTION A first object of the present invention made in view of the above problem is to economically provide a display device having an active matrix substrate having a high performance thin film transistor circuit in a pixel portion arranged in a matrix shape. A second object is to provide a specific manufacturing technique for solving these problems. In addition, the present invention is not limited to the modification of the semiconductor film formed on a glass substrate or the like for a display device, and can be similarly applied to the modification of the semiconductor film formed on another substrate, for example, a silicon wafer.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the structure sequence of the active matrix board | substrate in 1st Example of a display apparatus.

FIG. 2 is a plan view schematically illustrating a laser light irradiation pattern for modifying a silicon film of an active matrix substrate in a first embodiment of a display device; FIG.

3 is a schematic structural diagram of a laser light irradiation apparatus for modifying a silicon film of an active matrix substrate in a first embodiment of a display device;

4 is a flowchart for explaining the procedure of a laser beam irradiation operation for modifying a silicon film of an active matrix substrate in the first embodiment of the display device;

Fig. 5 is a three-dimensional explanatory diagram of laser light irradiation for modifying a silicon film of an active matrix substrate in the first embodiment of the display device.

6 is a diagram schematically illustrating the configuration of a laser light irradiation unit and a thin film transistor.

7 is a plan view illustrating a relationship between a pixel portion and a laser light irradiation area of an active matrix substrate.

Fig. 8 is a plan view for explaining a relationship between a pixel portion and a laser light irradiation area of an active matrix substrate in the first embodiment.

Fig. 9 is a sectional view schematically showing the construction procedure of an active matrix substrate in a third embodiment of the display device.

10 is a plan view of an example of a pattern of a laser beam irradiation unit for explaining the fifth embodiment;

11 is a plan view of another pattern example of the laser light irradiation unit for explaining the fifth embodiment;

12 is a plan view of an example of a pattern of a laser beam irradiation unit for explaining the fifth embodiment;

13 is a plan view of another pattern example of the laser light irradiation unit for explaining the fifth embodiment;

14 is a plan view of still another pattern example of the laser light irradiation section for explaining the fifth embodiment;

15 is a plan view of still another pattern example of the laser light irradiation section for explaining the fifth embodiment;

16 is a plan view for explaining the layout of a pixel portion of a conventional TN liquid crystal, as compared with the fifth embodiment;

17 is a plan view illustrating a layout of a pixel portion of a TN liquid crystal of the present invention, showing an example of the fifth embodiment.

18 is a plan view for explaining a layout of the pixel portion of the TN liquid crystal of the present invention, showing another example of the fifth embodiment.

Fig. 19 is a plan view for explaining a layout of a pixel portion of a conventional IPS liquid crystal compared with the fifth embodiment.

20 is a plan view for explaining the layout of the pixel portion of the IPS liquid crystal of the present invention, showing an example of the fifth embodiment.

21 is a plan view of a pattern example of a laser light irradiation section including a pixel section and a peripheral circuit section for explaining the fifth embodiment;

22 is a plan view of an active matrix substrate, illustrating a sixth embodiment.

Fig. 23 is a sectional view schematically illustrating the structure of a thin film transistor included in an active matrix substrate of a seventh embodiment.

24 is an explanatory diagram of a further improved structural example of a laser light irradiation apparatus for realizing the manufacturing method of the present invention.

25 is an external view showing an example of an electronic apparatus using the display device according to the present invention;

Fig. 26 is an explanatory diagram of a crystallization method according to scanning of a typical excimer pulse laser light irradiation;

FIG. 27 is a partial plan view of a laser light irradiation section and a principal part plan view illustrating a configuration example of the thin film transistor section in FIG. 26; FIG.

<Explanation of symbols for main parts of drawing>

101: substrate

102 SiN film

103: SiO film

104: amorphous silicon film

105: silicon film

106: gate electrode (or gate wiring)

107: interlayer insulating film

108: source / drain wiring

109: passivation film

110: transparent electrode

As a means for solving the above problems, the present invention selectively irradiates a laser beam (hereinafter also referred to as laser light) to the silicon film of the pixel portion to form a pixel circuit in the modified silicon film of the pixel portion. This pixel circuit is mainly a thin film transistor. In the manufacture of the active matrix display device according to the present invention, preferably, a laser beam is selectively irradiated to the silicon film of the pixel portion by using a reciprocating operation to form a pixel circuit on the modified silicon film of the pixel portion. More preferably, the pixel circuit portion is arranged intensively, and the laser beam is selectively irradiated to the silicon film of the pixel portion by using a reciprocating operation on the integrated portion to form a pixel circuit on the modified silicon film of the pixel portion.

The modification of the silicon film according to the present invention and the modification of the silicon film in the prior art have different contents, and the difference will be described as follows. In other words, in the modification of the silicon film of the present invention, the silicon film crystallized by the modification is an aggregate of single crystals having a width of 0.1 µm to 10 µm and a length of about 1 µm to 100 µm, thereby ensuring good carrier mobility. The value may be approximately 300 cm 2 / V · s or more, and preferably 500 cm 2 / V · s or more as the electron mobility.

On the other hand, in the modification of the silicon film using the conventional excimer laser, many of the crystallized silicon particles having a diameter of about 0.05 μm to 0.5 μm grow uniformly in the laser light irradiation part. As the electron mobility, a silicon film of about 100 cm 2 / V · s or less and on average about 50 cm 2 / V · s is obtained. Although the performance of such a conventional silicon film is improved compared to 1 cm 2 / V · s or less, which is the electron mobility of an amorphous silicon film, the present invention is characterized by using a modification superior to such a conventional modification. It should be emphasized that the contents of the and the prior art are different.

The silicon film of the pixel portion of the active matrix substrate constituting the display device according to the present invention is an amorphous silicon film (amorphous silicon film) formed by the CVD method, and the modified silicon film of the pixel portion is preferably a polysilicon film (polycrystalline silicon film). . However, the present invention is not limited to this, and it is also possible that the silicon film of the pixel portion is a polysilicon film modified from an amorphous silicon film, and the modified silicon film of the pixel portion is a more modified polysilicon film. The term "modified polysilicon film" as used herein means that the silicon film is crystallized from amorphous silicon, and the grain boundaries of the respective crystals are basically closed. In addition, the "more modified polysilicon film" means the state which changed into what has the crystal structure in which the grain boundary is continuous in a predetermined direction.

Further, the present invention may be a polysilicon film in which the silicon film of the pixel portion is formed by the sputtering method, and the modified silicon film of the pixel portion may be a more modified polysilicon film. Further, the silicon film of the pixel portion is a polysilicon film formed by CVD, and a combination such that the modified silicon film of the pixel portion is a more modified polysilicon film is also possible.

In the present invention, since the laser beam is selectively irradiated to the silicon film of the pixel portion on the substrate, a region to be selectively irradiated, that is, a region of modified silicon is formed in a stripe shape along the substrate surface. By actively adopting such a shape, there is no need to irradiate a laser beam to a region other than the pixel portion removed by etching in the process of forming a thin film transistor, and unnecessary work can be greatly reduced.

The laser used in the present invention is preferably a continuous oscillation solid laser having an oscillation wavelength of 400 nm to 2000 nm. The continuous oscillation laser beam preferably has a visible wavelength from an absorption wavelength, that is, an ultraviolet wavelength, to an amorphous or polycrystalline silicon thin film to be annealed, and more specifically, an Ar laser or Kr laser and its second harmonic, Nd: YAG laser, and Nd. The second harmonic and the third harmonic of the: YVO ₄ laser and the Nd: YLF laser can be applied. However, considering the magnitude and stability of the output, the second harmonic (wavelength 532 nm) of LD (laser diode) excited Nd: YAG laser or the second harmonic (wavelength 532 nm) of Nd: YVO ₄ laser is most preferred. The upper limit and the lower limit of the laser wavelength are determined from the balance between the range in which the light absorption of the silicon film occurs efficiently and a stable laser light source that can be obtained economically.

The solid-state laser of the present invention is not only capable of stably supplying laser light absorbed in the silicon film, but also has a low economic burden such as gas exchange work and deterioration of the transmitting part peculiar to the gas laser, and means for economically modifying the silicon film. It is preferable as. However, the present invention does not actively exclude that the laser is an excimer laser having a wavelength of 150 nm to 400 nm.

In the present invention, it is preferable to optically adjust the laser beam, uniformize the spatial distribution of the intensity, and then focus and irradiate using a lens system, and in order to adjust the crystallinity of the modified silicon film, the continuous oscillation laser beam is optically molded. It is preferable to irradiate after making it pulse. In this case, the pulse width of the laser is preferably selected in the range of 100 mW or more and 1 mW or less.

In this invention, it is preferable that the irradiation width at the time of irradiating a laser beam in stripe shape to a board | substrate is 20 micrometers-100 micrometers. This width is determined in consideration of economical efficiency from both the width of the region required for the pixel portion circuit and the ratio of the width to the pixel pitch. The length of the irradiation section is determined in consideration of the size of the substrate and the size of the pixel region. In the present invention, laser beam irradiation may be intermittently carried out in synchronization with the scanning of the stage, and in this case, the effect of the present invention is not lost.

In this invention, the said laser beam irradiation is characterized by scanning at a speed | rate of 1 mm / s-100 mm / s. This lower limit of scanning speed is determined from the balance of time and economic burden required to scan a predetermined area within the substrate, and the upper limit is limited from the ability of the machine equipment required for scanning.

In the present invention, the laser irradiation is performed by scanning a beam converging a laser beam into an optical system. In this case, an optical system converging a single laser beam into a single beam may be used. However, by dividing and irradiating a single laser beam into a plurality, it is possible to irradiate the columns of the plurality of pixel portions by simultaneous scanning, so that the efficiency of irradiation of the laser beam is remarkably improved. It is a preferable aspect of the present invention to irradiate a plurality of laser beams. Such a laser beam scanning mode is particularly preferable when a large size substrate is processed in a short time.

Moreover, in this invention, when the said laser beam irradiation was irradiated by operating a some laser oscillator in parallel, the efficiency of laser irradiation improves remarkably. This aspect is also particularly preferable when processing a large size substrate in a short time.

Further, in the present invention, the laser beam irradiation region selectively scanned is not limited to the pixel circuit portion, so that the peripheral circuit portion may be formed. The selection for irradiating the laser light to the formation region of the peripheral circuit is recommended when the performance of the thin film transistor formed in the pixel circuit portion satisfies the performance required for the peripheral circuit. In such a case, the number of driving circuit chips (LSI driver, driver IC) required for driving the display can be greatly reduced, so the economic effect is also great.

In the present invention, the circuit formed of the modified silicon film is not limited to a general top gate thin film transistor circuit, but may be a bottom gate thin film transistor circuit. In the case where a short-channel circuit only of the N-channel MIS or the P-channel MIS is required, the bottom gate type may be rather preferable from the simplification of the manufacturing process. In this case, since the silicon film through the insulating film is modified on the gate wiring by laser irradiation, it is preferable to employ a high melting point metal as the gate wiring material, and use a gate wiring material mainly composed of tungsten (W) or molybdenum (Mo). This is one of the characteristics of the present invention.

By manufacturing using the means of the present invention described above, the efficiency of laser light irradiation is greatly improved, and as a result, an active matrix substrate having an arrangement pitch of the pixel circuit equal to the pixel pitch is obtained.

In consideration of the arrangement of the pixel circuits, however, as a surprising effect, the efficiency of laser light irradiation can be greatly improved. In the arrangement of such an improved pixel circuit, the circuit portions of two rows of pixels arranged at equal intervals are collectively arranged in the center portion of the column, and the laser film is irradiated by selectively irradiating laser light only to such concentrated pixel regions. Can increase the efficiency of about twice. In the present invention, the arrangement pitch of the pixel circuit is equivalent to twice the pixel pitch.

By using the active matrix substrate having the semiconductor structure of the pixel circuit or the peripheral circuit of the present invention, it is possible to provide a liquid crystal display device of excellent image quality at low cost. In addition, by using the active matrix substrate of the present invention, an organic EL display device having excellent image quality can be provided at low cost. In addition, the present invention can be applied not only to a liquid crystal display device and an organic EL display device but also to an active matrix display device of another method having the same semiconductor structure in a pixel circuit or a peripheral circuit.

<Example>

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described in detail using drawing.

First, the outline | summary of this invention is demonstrated with reference to FIGS. In addition, description of these drawings may overlap with description of the Example in embodiment mentioned later. First, a SiN film 102 and a SiO film 103 functioning as a barrier film on a substrate (hereinafter, referred to as a glass substrate) 101 in which glass is preferred are thinly deposited by means of CVD or the like, and thereon. The amorphous silicon film 104 is deposited by the CVD method to a thickness of about 50 nm (Fig. 1 (a)). The above-described layer structure of the barrier film, the film thickness, the film thickness of the silicon film and the like are examples, and it should be emphasized that this technique does not limit the present invention. Thereafter, only the pixel portion is irradiated with the laser irradiation method of the present invention to modify the silicon film in the portion where the pixel circuit is to be formed (Fig. 1 (b)).

The plane of the irradiation part in the said board | substrate is shown typically in FIG. The present invention shows that the modified silicon film 105 can be formed in a stripe shape parallel to a predetermined direction. An example of the apparatus for performing such laser beam irradiation is shown in FIG. The amorphous silicon film 104 of the present invention is provided on the drive stage 201 that moves the deposited glass substrate 101 in the XY direction, and the position alignment is performed using the reference position measuring camera 202. The reference position measurement signal 203 from the reference position measurement camera 202 is input to the control device 204.

The drive facility 205 finely adjusts the irradiation position based on the control signal 206 input from the control device 204, moves the drive stage 201 at a predetermined speed, and scans the glass substrate in one direction. do. In synchronism with this scanning, the laser light 208 from the irradiation facility 207 is irradiated to the amorphous silicon film 104, and the silicon film 104 is modified into the polysilicon film 105.

In the irradiation facility 207, a desired irradiation beam can be formed by disposing an optical system 210 such as a laser light source 209, a homogenizer, a reflection mirror 211, and a condenser lens system 212. The irradiation time, irradiation intensity, and the like of the laser light are adjusted by the on-off (hereinafter, ON-OFF) signal 213 and control signal 214 from the control device 204. 4 shows a flowchart of this irradiation sequence. In the present invention, it may be emphasized that the speed of irradiation can be greatly improved by operating a plurality of irradiation facilities 207 that perform the scanning in parallel.

In the present invention, after irradiating the substrate onto the substrate in one direction (x direction) by the above-described operation, the relative position of the irradiation apparatus 207 and the glass substrate is moved slightly in another direction (y direction) intersecting in the one direction. It is preferable to use the irradiation method of the reciprocating operation which irradiates while scanning in the reverse direction. Since this reciprocating operation can effectively use the scanning time of a stage for irradiation, there exists an effect which significantly reduces the time required for irradiating all the pixel parts on a glass substrate.

The laser beam irradiation of the present invention will be described in more detail as shown in FIG. 5. In the present invention, condensing is performed on the amorphous silicon film 104 formed on the glass substrate 101 shown in FIG. 5A with the base film (not shown) interposed therebetween as shown in FIG. 5B. The irradiation part is scanned in the x direction while irradiating one laser light 208. As a result, the modified silicon film 105 can be formed in a narrow band shape (stripe shape). FIG. 6 is a diagram schematically illustrating the configuration of the laser light irradiation unit and the thin film transistor of the present invention. FIG. 6A is a plan view of the laser light irradiation unit, and FIG. 6B is a view illustrating the structure of the thin film transistor. One floor plan.

As shown in FIG. 6A, laser light is irradiated onto the amorphous silicon film 104 on the glass substrate 101 to irradiate the laser light, so that crystallized silicon is scanned in the laser light irradiation part (x in FIG. 6). Along the direction of growth). The transistor portion TRA shown in dotted lines is formed in the growth region of the crystallized silicon, that is, in the region of the polysilicon film.

The modification of the silicon film of the present invention refers to such crystallization, and the crystallized portion is an aggregate of single crystals having a band width of 0.1 µm to 10 µm and a length of about 1 µm to 100 µm. By forming the pixel circuit using the modified silicon film 105, the efficiency of modification is greatly improved. Specifically, in order to use a portion of the crystallized silicon film as the transistor portion TRA shown in Fig. 6A, unnecessary portions are removed by etching to remove the island PSI of the silicon film as shown in Fig. 6B. The gate insulating film (not shown), the gate electrode GT, the source electrode SD1, and the drain electrode SD2 are disposed on the island PSI to form a MIS transistor. The technique for forming such a transistor is well known to those skilled in the art. In addition, the spot shape of laser beam irradiation on a glass substrate can also be shape | molded in shapes, such as ellipse, spherical shape, and rectangle, in addition to shape | molding circularly. This shape is the range which can be adjusted with an optical system.

In the present invention, the modified silicon film 105 formed as described above is etched so as to be a predetermined circuit as shown in Fig. 1C, and the gate insulating film (not shown) and the gate electrode (or gate wiring) are 106, the interlayer insulating film 107, the source / drain wiring 108, the passivation film 109, and the transparent electrode 110 serving as the pixel electrode are sequentially formed. As a result, an active matrix substrate can be formed in which a transistor circuit using the modified silicon film 105 is disposed in a pixel. The details of the transistor circuit and the processing technology related to the formation of the electrode are well known to those skilled in the art. It is also well known that additional processes such as ion implantation and activation annealing are required during the process.

7 is a plan view illustrating a relationship between a pixel portion and a laser light irradiation area of an active matrix substrate of the present invention. 7 does not necessarily correspond to the actual size, but schematically illustrates the relationship between the pixel 401, the pixel circuit portion 402, and the laser light irradiation portion 403. In the present invention, it can be seen that the area of the laser irradiation part 403 can be made about 1/2 to 1/5 of the area of the whole pixel part.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail with reference to drawings of an Example.

[First Embodiment]

A first embodiment of the present invention will be described with reference to FIGS. 1 to 5 and 8. 1 is a cross-sectional view schematically showing a configuration procedure of an active matrix substrate in a first embodiment of a display device according to the present invention, and FIG. 2 is an active matrix substrate in a first embodiment of a display device according to the present invention. 3 is a plan view schematically illustrating a laser light irradiation pattern for modifying a silicon film, and FIG. 3 is a schematic structure of a laser light irradiation apparatus for modifying a silicon film of an active matrix substrate in a first embodiment of a display device according to the present invention. 4 is a flowchart for explaining a procedure of laser light irradiation operation for modifying a silicon film of an active matrix substrate in a first embodiment of the display device according to the present invention, and FIG. 5 is a first view of the display device according to the present invention. It is a three-dimensional explanatory drawing of laser light irradiation for modifying the silicon film of the active matrix substrate in the embodiment. 8 is a plan view for explaining the relationship between the pixel portion and the laser light irradiation area of the active matrix substrate in the first embodiment of the present invention.

First, as shown to Fig.1 (a), the thickness is about 0.3 mm-about 1.0 mm, Preferably the heat resistant glass substrate 101 with little deformation | transformation and shrinkage is prepared by the heat processing of 400 degreeC-600 degreeC. . On this glass substrate 101, a SiN film 102 having a thickness of about 50 nm and a SiO film 103 having a thickness of about 50 nm that function as thermal and chemical barrier films are continuously and uniformly deposited by CVD. An amorphous silicon film 104 is deposited on the barrier film to a thickness of about 50 nm by the CVD method. The deposition method of a barrier film and an amorphous silicon film using such a CVD method is well known to those skilled in the art. Thereafter, only the pixel portion is irradiated with the laser light irradiation method of the present invention, and the silicon film of the portion where the pixel circuit is to be formed is modified from the amorphous silicon film to the polysilicon film 105 by laser light irradiation.

FIG. 1B is a cross-sectional view showing a state in which an amorphous silicon film of a required portion is modified into a polysilicon film by irradiation of laser light. The apparatus shown in FIG. 3 can be used as an apparatus for irradiating the laser beam shown to FIG. 1 (b). The outline of the laser light irradiation using this irradiation apparatus overlaps with the description in the above-described solution section, but in the present embodiment, the glass substrate 101 on which the amorphous silicon film 104 is deposited has a driving stage (in the xy direction). 201), and position alignment is performed using the camera 202 for reference position measurement. The reference position measurement signal 203 is input to the control device 204, and fine adjustment of the irradiation position is performed on the basis of the control signal 206 input to the drive device 205, thereby operating the stage 201 at a predetermined speed. It moves and scans in one direction (x direction of FIG. 1). In synchronization with such scanning, the laser light 208 from the irradiation facility 207 is irradiated to the amorphous silicon film 104 to modify the silicon film.

As described above, in the irradiation facility 207, for example, an optical system such as a 1 W laser light source 209, a homogenizer, etc., which is composed of the second harmonic (wavelength 532 nm) of the Nd: YVO ₄ laser of LD (laser diode) excitation. The desired irradiation beam can be formed by disposing the 210, the reflection mirror 211, and the condenser lens system 212. The irradiation time, irradiation intensity, and the like of the laser light are adjusted by the ON-OFF signal 213 and the control signal 214 from the control device 204.

FIG. 4 is a flowchart for explaining an irradiation sequence of laser light using the irradiation apparatus of FIG. 3. In the present embodiment, it is preferable to optically adjust the laser light, uniformize the spatial distribution of the intensity, and then focus and irradiate the light using a lens system. In addition, in order to adjust the crystallinity of the modified silicon film, it is preferable to irradiate after the continuous oscillation laser light is optically molded and pulsed. In this case, the pulse width of the laser is preferably selected in the range of 100 mW or more and 1 mW or less. For example, in order to obtain a particle diameter of 5 m, the pulse width is selected to 10 mW as an optimal laser condition.

In FIG. 2, the irradiation part in a board | substrate is shown typically in plan view, and shows that the modified silicon film 105 can be formed in stripe form in this Example. Since the irradiation beam diameter of the laser light is required to be larger than the width of the circuit area of the pixel portion, 30 mu m is selected as an example.

In this embodiment, as shown in Fig. 8, the substrate is irradiated in the x direction (A direction = the above-described direction) by the above operation, and then shifted slightly in the y direction to scan in the reverse direction (B direction) along the x direction. It is preferable to use the method of irradiating a board | substrate surface to the reciprocation operation | movement irradiated in two dimensions. 300 Pa is selected as an example of the scanning speed. By repeating this reciprocating operation, the silicon films of all the pixel portions can be modified into polysilicon films of good quality. The modified polysilicon film has a characteristic crystal form in which a single crystal region grows in one direction asymmetrically as shown in Fig. 6 along the irradiation direction of the laser light.

The modified silicon film 105 formed as described above is etched to form a predetermined circuit as shown in Fig. 1C, and a gate insulating film (not shown) and a gate electrode (Fig. 6B). The modified silicon film 105 by sequentially forming the gate electrode GT 106, the interlayer insulating film 107, the source / drain wiring 108, the passivation film 109, and the transparent electrode 110 serving as the pixel electrode. ), An active matrix substrate having a transistor circuit arranged on the pixel circuit is formed.

In the formation of such a transistor circuit, it is preferable that the arrangement of electrons or holes in the gate portion coincide in parallel with the crystal growth direction. The coincidence in parallel means that the angle with respect to the crystal growth direction of the polysilicon film is 0 degrees or 180 degrees. The allowable error for this angle is within about 30 degrees. The reason is shown in Table 1.

Direction (deg) Electron Mobility (㎠ / Vs) 0 520 30 500 60 260 90 150 120 220 150 510 180 580

Table 1 shows the results of verifying the relationship between the direction of electron movement, the scanning direction (angle: deg) and the electron mobility (cm 2 / Vs) of laser light irradiation. As shown in Table 1, the relationship between the angle (absolute value) formed by the direction of crystal growth defined by the scanning direction of laser light irradiation and the electron mobility is about 300 degrees when it is shifted to about 30 degrees or less with respect to 0 degrees or 180 degrees. 2 cm 2 / V · s or more can be sufficiently secured. On the other hand, when the error with the said direction of crystal growth exceeds 30 degree | times, it turned out that electron mobility falls and the electron mobility falls extremely in the perpendicular direction (90 degree | times). This embodiment is based on this knowledge. This also applies to other embodiments described later.

The feature of this arrangement is that the present embodiment (the whole of the present invention including the other embodiments described later) allows the reciprocating operation of laser light irradiation. If the layout of the pixel circuits is the same, the pixel circuit portion (scanning portion in the A direction in Fig. 8) formed in the laser light irradiation portion 403 formed from the road and the laser irradiation portion 403 formed from the return path In the pixel circuit portion (scanning portion in the B direction in FIG. 8) formed in the gap, a difference of 0 degrees or 180 degrees occurs between the carrier movement direction and the crystal growth direction. In the present invention including the present embodiment, it has been found that such a difference hardly affects the transistor characteristics, thereby allowing two kinds of arrangements of 0 degrees and 180 degrees. It should be emphasized that round trip investigations are possible based on these nonobvious results.

As described above, the possibility of carriers crossing the grain boundaries can be reduced by the arrangement of the positive crystal directions, so that deterioration of characteristics due to grain boundary scattering can be minimized, thereby obtaining the best transistor circuit. . Details of this kind of transistor circuits and processing techniques related to electrode formation are well known to those skilled in the art. It is also well known that additional processes such as ion implantation and activation annealing are required during the process.

In this manner, a thin film transistor circuit using a polysilicon semiconductor film can be arranged in the pixel portion. The performance of the thin film transistor obtained in this embodiment is, for example, when an N-channel MIS transistor is produced, the field effect mobility is about 300 cm 2 / V · s or more, and the variation in the threshold voltage is ± 0.2 V or less. It can be suppressed, and it can operate with high performance and high reliability, and can manufacture the display apparatus using the active-matrix board | substrate excellent in the uniformity between devices.

In this embodiment, a P-channel MIS transistor can be manufactured by boron implantation, which gives a hole carrier, instead of the ion implantation of phosphorus, which imparts an electron carrier, and the N-type and P-type are exchanged on the same substrate by changing the arrangement of the photomask. It is also possible to form a so-called CMOS circuit. In the CMOS circuit, the frequency characteristic can be improved, which is suitable for high speed operation. However, as the number of masks increases, an increase in the manufacturing process becomes a betrayal factor. The details of such semiconductor manufacturing technology and semiconductor circuit technology are well known to those skilled in the art, and it is required to optimize the semiconductor device in consideration of the characteristics required for the display device and the cost for manufacturing.

The technical method for manufacturing a liquid crystal display device using the active matrix substrate of this embodiment is well known to those skilled in the art. Specifically, after forming a liquid crystal aligning film layer on an active-matrix board | substrate, giving an orientation control force to it by methods, such as a rubbing, and forming a sealing compound in the periphery of a pixel part, the color filter substrate which similarly formed the alignment film layer hereafter It arrange | positions in a predetermined gap and opposes a liquid crystal in this gap, and closes the sealing opening of a sealing compound with a sealing material, and forms a liquid crystal cell.

Thereafter, the gate driver LSI and the source driver LSI are mounted on the periphery of the liquid crystal cell to form a liquid crystal display module. A liquid crystal display device can be manufactured by mounting a polarizing plate, a light guide plate, a backlight, etc. in this liquid crystal display module.

The liquid crystal display device using the active matrix substrate of the present embodiment is suitable for high-speed operation since the excellent polysilicon thin film transistor circuit is disposed in the pixel circuit, so that the current driving capability is excellent. In addition, since the variation of the threshold voltage is small, the uniformity of image quality is excellent and the liquid crystal display device can be provided at low cost.

Incidentally, an organic EL technology method of manufacturing an organic EL display device using the active matrix substrate of this embodiment is well known to those skilled in the art. Specifically, a bank pattern for separating organic EL elements is formed on an active matrix substrate, and a hole transport layer, a light emitting layer, an electron transport layer, a cathode metal layer, and the like are sequentially deposited from the transparent electrode surface to form a laminate. The sealing material is arrange | positioned around the pixel part of the board | substrate which formed such a laminated layer, and it seals with a sealing can. This sealing technique protects the organic EL of the pixel portion from moisture and the like. It is necessary to protect organic EL from moisture and the like in order to suppress deterioration of image quality, and it is recommended to provide a desiccant in a sealed can.

In the active matrix drive for organic EL display devices, since the organic EL element is a current driven light emission system, the adoption of a high performance pixel circuit is essential for providing a good quality image, and it is particularly preferable to use a CMOS pixel circuit. It is emphasized that the active matrix substrate of this embodiment is suitable as a high performance active matrix substrate in response to such a requirement, and that the organic EL display device using the active matrix substrate of this embodiment is one of the display devices that exhibits the features of this embodiment to the maximum. Should be.

Second Embodiment

In this embodiment, the silicon film to be modified by irradiating laser light is not limited to the amorphous silicon film, but may be a polysilicon film modified from the amorphous silicon film, and the modified silicon film of the pixel portion may be a more modified polysilicon film. Do. In this embodiment, the silicon film of the pixel portion may be a polysilicon film formed by sputtering, and the modified silicon film of the pixel portion may be a more modified polysilicon film. Further, the silicon film of the pixel portion is a polysilicon film formed by CVD, and a combination such that the modified silicon film of the pixel portion is a more modified polysilicon film is also possible. An embodiment of the invention in which a silicon film different from the first embodiment described above is modified will be described with reference to the above drawings.

Similarly to the first embodiment, the heat resistant glass substrate 101 having a thickness of about 0.3 mm to 1.0 mm and preferably less deformation and shrinkage is prepared by heat treatment at 400 ° C to 600 ° C. On this glass substrate, a SiN film 102 having a thickness of about 50 nm and a SiO film 103 having a thickness of about 50 nm, which functions as a thermal and chemical barrier film, are continuously and uniformly deposited by CVD. The amorphous silicon film 104 is deposited on the film by a CVD method to a thickness of about 50 nm (see Fig. 1A).

The crystallization method of scanning the excimer pulse laser light irradiation with respect to this amorphous silicon film will be described with reference to FIG. 26 described above. A linear excimer laser beam having a width of several mm to several 100 mm in an amorphous silicon film 302 deposited on a glass substrate 301 with a base film (not shown) interposed therebetween as shown in FIG. 26A. By irradiating 303 and moving the irradiation position to one to several pulses, a large area of the amorphous silicon film 302 becomes a modified silicon film 304. By performing such wide area irradiation on the entire substrate, the amorphous silicon film can be modified into a polysilicon film.

The crystallinity of the polysilicon can be further improved by modifying the silicon film modified by the excimer pulsed laser light by the laser light irradiation of the present embodiment as in the first embodiment. In the embodiment of the present embodiment, after the modification by the laser light irradiation of the present embodiment, the liquid crystal display device using the active matrix substrate and the active matrix substrate of the present invention can be produced in the exact same procedure as in the first embodiment.

Particularly noteworthy feature of this embodiment is that the polysilicon film produced by the laser light irradiation is produced from the amorphous silicon film even though the silicon film in which the microcrystals are generated in advance by excimer pulsed laser light irradiation is used. There is nothing different from the act. That is, even when the excimer pulse laser light irradiation is performed, in the thin film transistor using the polysilicon film obtained in the present embodiment, for example, when an N-channel MIS transistor is produced, the field effect mobility is about 300 cm 2 / V · s As described above, the variation of the threshold voltage can be suppressed to ± 0.2 V or less, so that an active matrix substrate can be manufactured with high performance and high reliability, and excellent in uniformity between devices. A display device can be obtained.

As known in the art, it is possible to crystallize an amorphous silicon film using excimer pulsed laser light irradiation. In such crystallization, a polysilicon film made of fine crystals of about 1 μm or less is obtained. In the thin film transistor formed of this polysilicon film, for example, when an N-channel MIS transistor is produced, the field effect mobility is about 100 cm 2. It is about / V * s or less, and the variation of a threshold voltage is also large. Even when compared with such well-known knowledge, one end of the outstanding effect of a present Example can be seen.

Third Embodiment

In this embodiment, the silicon film to be modified by irradiating laser light is not limited to the amorphous silicon film. As also described in the embodiment described in the above-described second embodiment, the silicon film of this embodiment may be a polysilicon film modified from an amorphous silicon film, or a polysilicon film further modified with a modified silicon film in the pixel portion. In this embodiment, the silicon film of the pixel portion may be a polysilicon film formed by sputtering, and the modified silicon film of the pixel portion may be a more modified polysilicon film. Further, the silicon film of the pixel portion is a polysilicon film formed by CVD, and a combination such that the modified silicon film of the pixel portion is a more modified polysilicon film is also possible. Another embodiment of the present invention modified for a silicon film different from the above embodiment will be described below with reference to FIG.

9 is a cross-sectional view schematically showing the configuration procedure of an active matrix substrate in a third embodiment of the display device according to the present invention. Similarly to the first embodiment, the heat resistant glass substrate 501 having a thickness of about 0.3 mm to 1.0 mm, preferably less deformation and shrinkage by heat treatment at 400 ° C to 600 ° C is prepared. On this glass substrate 501, a SiN film 502 having a thickness of about 50 nm and a SiO film 503 having a thickness of about 50 nm that function as thermal and chemical barrier films are continuously and uniformly deposited by CVD. A silicon film 504 is deposited on the barrier film by a CVD method with a thickness of about 50 nm by sputtering (see FIG. 9A).

Thereafter, only the pixel portion is irradiated to the pixel portion by the laser light irradiation method using the same device as described in the first embodiment, and the silicon film of the portion where the pixel circuit is to be formed is irradiated with polysilicon from the amorphous silicon film 504 by laser light irradiation. The film 505 is modified (see FIG. 9B). The silicon film 505 modified in this manner is etched to form a predetermined circuit as shown in Fig. 9C, so as to form a gate insulating film (not shown), a gate wiring (which becomes a gate electrode) 506, The interlayer insulating film 507, the source / drain wiring 508, the passivation film 509, and the transparent electrode 510 serving as the pixel electrode are sequentially formed. As a result, an active matrix substrate in which a transistor circuit using the modified silicon film 505 is arranged in a pixel is formed.

In the formation of such a transistor circuit, it is also the same as in the first embodiment that it is preferable that the movement direction of electrons or holes in the gate portion coincide in parallel with the growth direction of the crystal of the silicon film.

Also in this embodiment, the difference in the crystal growth direction based on the reciprocating operation of the laser light irradiation causes a difference of 0 degrees or 180 degrees between the carrier movement direction and the crystal growth direction of the thin film transistor in the pixel portion. It should be noted that even in this case, this difference hardly affects transistor characteristics. The relationship between the angle (absolute value) formed by the direction of electron movement and the direction of crystal growth defined by the laser scanning direction of the present invention and the electron mobility is as described using Table 1 in the first embodiment.

The performance of the thin film transistor included in the active matrix substrate obtained in the present embodiment is superior to that of the first and second embodiments. For example, in the case of producing an N-channel MIS transistor, the field effect mobility is about 300 cm 2 / V · s or more, and the variation in the threshold voltage can be suppressed to ± 0.2 V or less.

The method for manufacturing a liquid crystal display device using the active matrix substrate according to the present embodiment is well known as described in the first and second embodiments, and the high speed display operation is obtained by using the liquid crystal display device. A display device excellent in uniformity of image quality can be provided at low cost.

[Example 4]

In this embodiment, the silicon film to be modified by irradiating laser light is not limited to the amorphous silicon film. As described in the above embodiment, the polysilicon film modified from the amorphous silicon film and the modified silicon film of the pixel portion are It is also possible to be a more modified polysilicon film. Further, the present embodiment may be such that the silicon film of the pixel portion is formed by the sputtering method, and the modified silicon film of the pixel portion is a more modified polysilicon film. In addition, a combination is also possible in which the silicon film of the pixel portion is a polysilicon film formed by CVD, and the modified silicon film of the pixel portion is a more modified polysilicon film.

Similarly to the first embodiment, the thickness is about 0.3 mm to 1.0 mm, and a heat resistant glass substrate having less deformation and shrinkage is preferably prepared by heat treatment at 400 ° C to 600 ° C. About 50 nm thick SiN film 502 and about 50 nm thick SiO film 503 functioning as a thermal and chemical barrier film are continuously and uniformly deposited on this glass substrate. A polysilicon film is deposited to a thickness of about 50 nm on the barrier film by CVD.

The technique for depositing a polysilicon film by the CVD method is also well known to those skilled in the art, and by adopting the method of this embodiment, the crystallinity of the polysilicon film obtained by the CVD method can be greatly improved. The effect of this embodiment shows that a stable polysilicon film is obtained after irradiation without depending on the film quality of the silicon film to be irradiated with laser light, which is also a feature of this embodiment.

The method of manufacturing the liquid crystal display device using the active matrix substrate according to the present embodiment is well known as described in the first to third embodiments, and the high speed display operation is obtained by using the liquid crystal display device. The display device excellent in the uniformity of image quality can be provided at low cost.

[Example 5]

This embodiment will be described with reference to FIGS. 10, 11, 12, 13, 14, and 15. This embodiment considers the arrangement of the pixel circuit on the active matrix substrate as one of the embodiments of the present invention, and makes it possible to greatly improve the efficiency of laser irradiation of the present invention.

10 is a plan view of an example of a pattern of a laser light irradiation unit for explaining a fifth embodiment of the present invention, FIG. 11 is a plan view of another pattern example of a laser light irradiation unit for explaining a fifth embodiment of the present invention, and FIG. 12 is an embodiment of the present invention. 13 is a plan view of another pattern example of the laser light irradiation section explaining the fifth embodiment, FIG. 13 is a plan view of another pattern example of the laser light irradiation section explaining the fifth embodiment of the present invention, and FIG. 14 is a description of the fifth embodiment of the present invention. Fig. 15 is a plan view of yet another example of the pattern of the laser light irradiation section, and Fig. 15 is a plan view of another pattern example of the laser light irradiation section for explaining the fifth embodiment of the present invention.

In the patterns of the laser beam irradiator shown in FIGS. 10, 11, 12, 13, 14, and 15, a circuit of two columns of pixels 601 arranged at equal intervals in the x direction in any of the arrangements of the pixel circuits. Columns of the pixel region consisting of the portions 602 are intensively arranged in adjacent central portions in the y direction.

By only using the collectively arranged pixel areas as the selective laser irradiation area 603, the efficiency of laser irradiation is increased by about twice. The pattern of these laser light irradiation sections is characterized in that the arrangement pitch of the pixel circuit is equal to twice the pixel pitch.

In the pixel arrangement method, in addition to the examples shown in FIGS. 10, 11, 12, 13, 14, and 15 described above, the arrangement pitch of the pixel circuit is equal to twice the pixel pitch. Inclusion in the examples should be emphasized. In addition, the selection of any of these arrangements should be optimized in consideration of the wiring design on the gate side and the source side of the thin film transistor to be formed, the layout (pixel arrangement) of the pixel circuit, and the driving method of the pixel circuit.

In addition, the manufacturing method of the specific active matrix substrate may be the same as the method described in the first embodiment, and the irradiation efficiency of the first embodiment is selected by selecting, for example, about 70 μm in accordance with the laser beam irradiation width in accordance with the pixel-intensive arrangement. That's about twice as high. It is also emphasized that laser irradiation can apply reciprocal scanning even in such an arrangement.

Next, the arrangement (layout) of the pixel portion in the case where the present embodiment is specifically applied to the liquid crystal display device will be described with reference to FIGS. 16, 17, 18, 19, 20, and 21. 16 is a plan view of a pixel arrangement of a pixel portion of a conventional TN type liquid crystal display device for comparing and explaining a fifth embodiment of the present invention, and FIG. 17 is a TN type liquid crystal display device showing an example of a fifth embodiment of the present invention. 18 is a plan view of a pixel arrangement of a pixel portion, FIG. 18 is a plan view of a pixel arrangement of a pixel portion of a TN type liquid crystal display device for explaining another example of the fifth embodiment of the present invention, and FIG. 19 is a comparative description of a fifth embodiment of the present invention. 20 is a plan view of a pixel arrangement of a pixel portion of a conventional IPS type liquid crystal display device, FIG. 20 is a plan view of a pixel arrangement of a pixel portion of an IPS type liquid crystal display device showing an example of a fifth embodiment of the present invention, and FIG. It is a top view of the pattern example of the laser beam irradiation part containing the pixel part and the peripheral circuit part of the display apparatus explaining 5th Example.

The pixel arrangement of the conventional TN (twist nematic) type liquid crystal display device is typically as shown in FIG. 16 and is equivalent to the above-described FIG. In the pixel arrangement shown in FIG. 16, a driving transistor having a gate 1004 having a polysilicon 1002 is arranged at an intersection of the gate wiring 1006 and the data wiring 1008 arranged in a lattice shape to form a contact hole ( The connection is made through 1111 to control the voltage of the transparent electrode 1010 that is the pixel electrode. The storage (capacitance) portion 1110 for holding the display voltage is generally configured at an overlapping portion between the transparent electrode 1010 and the gate wiring 1006 at the front end.

The pixel arrangement of the TN type liquid crystal display of the present invention is typically as shown in FIG. 17 and is equivalent to FIG. 16. That is, by intensively arranging the gate wirings 1006 for two pixels with respect to the data wirings 1008 at equal intervals, the arrangement of the integrated thin film transistors can be realized. However, as in the conventional pixel arrangement shown in Fig. 16, it is not possible to construct the storage unit by using a part of the gate wiring at the front end. Therefore, it is necessary to form the storage wiring 1113 separately and to configure the storage portion in the overlapping portion with the transparent electrode 1010. When such a pixel arrangement is used, only by changing the layout of the exposure mask, the aperture ratio does not decrease, and a TN type liquid crystal display device can be manufactured by the same number of steps as in the conventional manufacturing process.

18 shows a representative pixel arrangement of another TN type liquid crystal display of the present invention. This pixel arrangement is an arrangement equivalent to that shown in FIG. Even in such a pixel arrangement, only by changing the layout of the exposure mask, the aperture ratio does not decrease, and the TN type liquid crystal display device can be manufactured by the same number of steps as in the conventional manufacturing process.

In addition, the pixel arrangement of the conventional in-plane switching (IPS) type liquid crystal display device is typically as shown in FIG. This is a pixel arrangement equivalent to FIG. In the pixel arrangement shown in Fig. 19, a thin film transistor having a gate 1004 having polysilicon 1002 is arranged at an intersection of the gate wiring 1006 and the data wiring 1008 arranged in a lattice shape, and the pixel electrode is arranged. 1114 is connected to the source electrode of the thin film transistor through the contact hole 1111 to control the voltage between the common electrode (counter electrode) 1115 and the pixel electrode 1114. The storage (capacitance) for holding this voltage is generally formed by forming the storage electrode 1115 in the storage wiring 1113 arranged in parallel with the gate wiring 1006.

The pixel arrangement of the IPS type liquid crystal display device of the present invention is typically as shown in FIG. 20 and is equivalent to the arrangement of FIG. 10. By intensively arranging the gate wirings 1006 for two pixels with respect to the data wirings 1008 at equal intervals, the arrangement of the integrated thin film transistors can be realized. Also in this case, it is necessary to form the storage wiring 1113 in parallel with the gate wiring 1006 to configure the storage portion. Even when such pixel arrangement is used, the IPS type liquid crystal display device can be manufactured by the same number of steps as the conventional manufacturing process without changing the aperture ratio only by changing the layout of the exposure mask.

As described in the above embodiments, the liquid crystal display device can be easily manufactured using the present invention. Similarly, an organic EL display device can also be manufactured.

In the above embodiment, all of the examples using the single-gate thin film transistor have been described, but the present invention is not limited thereto. In other words, even when a so-called double gate thin film transistor is used, the display device can be manufactured with the exact same pixel arrangement. In this case, while the area of the thin film transistor portion is slightly increased, the production yield can be improved since the advantages such as the suppression of off-leakage current and the improvement of breakdown voltage are large, and therefore, it is more preferable to employ in actual products.

Further, in the pixel arrangement according to the present invention, the arrangement of the gate driving circuit of the peripheral circuit portion (drive circuit portion) formed around the pixel region is equal to the arrangement pitch of the thin film transistor of the pixel portion, so that the pixel portion and the peripheral circuit portion are the method of the present invention. Can be formed simultaneously. That is, as shown in FIG. 21, the laser irradiation region 603 of the pixel portion forming the pixel 601 extends to the gate driving circuit portion 1200, which is the peripheral circuit portion, and forms a peripheral circuit in the extended region to form an active matrix substrate. Can greatly improve the productivity. In the case where the gate driving circuit 1200 is disposed in the extended region of the laser irradiation area 603, voltage conversion, impedance conversion, shift registers, various switches, protection using a thin film transistor formed of the modified silicon film of the present invention. The gate driving circuit 1200 including the circuit and the like can be realized. In the case of such an arrangement, it is a great feature of the present invention that the arrangement pitch of the pixel circuit portion is equal to the arrangement pitch of the peripheral circuit portion.

[Example 6]

In the laser irradiation of this embodiment, the pixel portion is irradiated with a laser beam on a pixel portion on the active matrix substrate, and the silicon portion of the portion where the pixel circuit should be formed is modified into a polysilicon film of good quality by laser light irradiation. The silicon film of the peripheral circuit portion disposed at the periphery is also modified, so that the peripheral circuit is formed of the same thin film transistor as the pixel portion.

22 is a plan view of an active matrix substrate for explaining a sixth embodiment of the present invention. In this embodiment, as in the first embodiment, a region modified by the polysilicon film 702 is formed by irradiating a laser beam in a stripe shape along the x direction only to the pixel portion of the amorphous silicon film 701 deposited on the glass substrate. do. The peripheral circuit portions 703 and 704 arranged around the pixel portion are also formed with a region irradiated with laser light by the method described in the first embodiment. In Fig. 22, the peripheral circuit portion 703 is the peripheral circuit portion on the source side, and the peripheral circuit portion 704 is the peripheral circuit portion on the gate side.

After that, a thin film transistor is formed in the peripheral circuit simultaneously with the pixel circuit in the same manner as in the first embodiment. According to the present embodiment, the driving integrated circuit (driver IC: LSI) required for driving the display device can be greatly reduced. Using a typical SXGA panel (1280 x 1024) as a large display device (large panel) as an example, the number of driver ICs in a commercial panel is about 14, but the number of ICs is at least 2 or less, preferably 0 when using the present invention. It can also be reduced by opening. In addition, if the liquid crystal display device is manufactured according to the present embodiment, the burden of the manufacturing process accompanying mounting of the IC can be reduced in addition to the reduction of the driver IC, so that a liquid crystal display with good quality and inexpensiveness can be provided. . This embodiment becomes possible result of the performance of the active matrix substrate obtained in this embodiment satisfying the high performance required for driving the peripheral circuit.

[Example 7]

In this embodiment, the circuit formed of the modified silicon film is not limited to the general top gate thin film transistor circuit, but it is also possible to use a bottom gate thin film transistor circuit. In the case where a short-channel circuit only of the N-channel MIS or the P-channel MIS is required, the bottom gate type may be rather preferable from the simplification of the manufacturing process. This embodiment is described below with reference to FIG. 23 in the case where the present invention is applied to a bottom gate type thin film transistor circuit.

Fig. 23 is a sectional view schematically illustrating the structure of a thin film transistor included in an active matrix substrate of a seventh embodiment of the present invention. In Fig. 23, the SiN film 802 and the SiO film 803 functioning as barrier films are deposited thinly on the glass substrate 801 by means of CVD or the like. The gate electrode 804 is formed on it in a predetermined shape. The gate insulating film 805 is formed to cover the gate electrode 804. Subsequently, an amorphous silicon film is deposited by CVD to a thickness of about 100 nm. In forming the amorphous silicon film, an N-type amorphous silicon film may be deposited by coexisting a predetermined amount of phosphine with silane gas in order to form an N-type MIS transistor.

Thereafter, the laser beam is irradiated only on the gate electrode 806 by the above-described laser beam irradiation method, and the portion where the pixel circuit is to be formed is modified with a polysilicon film. Subsequently, an N ⁺ layer is deposited to a thickness of about 20 nm by the CVD method in which the amount of phosphine is increased on the silicon film to form a laminated film. The laminated film thus formed is dry etched to have a predetermined shape at a predetermined position to form an island 806. A source / drain wiring 807 is formed in the formed island 806, and the exposed N ⁺ layers other than the source and drain wiring portions are removed by dry etching.

Next, by forming the passivation film 808 and the transparent electrode 809 sequentially, an active matrix substrate in which a transistor circuit using a silicon film modified from amorphous silicon to polysilicon is arranged in a pixel is produced. The outline of the processing technology related to such circuit formation and electrode formation is well known to those skilled in the art. It is also well known that addition of processes such as activation annealing is necessary during the manufacturing process.

In the above manufacturing process, the impurity carrier can be doped at the time of film formation by CVD, so that expensive and troublesome ion implantation can be omitted, which is very economical. Further, the P-type MIS may be produced by doping with borane gas so as to be a P-type carrier. Therefore, the adoption of the bottom gate type is an excellent method for economically providing a short channel type semiconductor device.

In the case of manufacturing the bottom gate thin film transistor according to the present invention as in the present embodiment, since the laser beam is irradiated to the silicon film on the gate wiring with the insulating film interposed therebetween, it is preferable to employ a high melting point metal as the gate wiring material. Do. Therefore, one of the features of this embodiment is that a wiring material mainly composed of tungsten (W) or molybdenum (Mo) is used as the gate wiring material.

[Example 8]

It is explanatory drawing of the further improved structural example of the laser beam irradiation apparatus for implementing the manufacturing method of this invention. In the present invention, since the laser beam is selectively irradiated to the silicon film of the pixel portion and the pixel circuit is formed on the modified silicon film of the pixel portion, plural laser beams are irradiated in parallel operation to increase productivity. It is effective to arrange a plurality of laser irradiation apparatuses in parallel as shown in FIG. 3 for parallelizing such laser light irradiation. However, as described below, it is also a very effective method to divide the beam oscillated from one laser light source into a plurality and parallelize it. In addition, in parallel installation of a laser beam irradiation apparatus, when the number is set to m, irradiation time can be shortened to about 1 / m compared with 1-to-1.

In the plural division of the laser light, as shown in Fig. 24, the laser beam 902 oscillated from the laser light source 901 is divided into an optical system 903 such as a homogenizer. It is effective to introduce the divided laser beam into the plurality of condensing lens systems 905 through a plurality of light guide paths such as the optical fiber 904 to form the plurality of irradiation beams 906. Although the beam splitting and light guide path creation technology itself is within the scope of optical technology, it should be emphasized that the time required for the modification of the silicon film can be surprisingly shortened using the technology according to the present invention. When the number of divisions of the laser light is n, the irradiation time can be shortened to about 1 / n as compared to when one to one. In addition, when the laser beam splitting and parallel installation are used in combination, the irradiation time can be shortened to about 1 / nm, which can dramatically improve the productivity of this type of active matrix substrate, and is not limited to such an active matrix substrate. When applied to the manufacture of various semiconductor devices, the productivity can be significantly improved.

25 is an external view showing an example of an electronic apparatus using the display device according to the present invention. This electronic device is a television receiver, and a panel PNL having the configuration of any of the above embodiments is mounted on the display unit, and the stand is placed upright. The panel PNL is also a liquid crystal display device, an organic EL display device, or another active matrix display device. Moreover, a stand part can also be made removable.

In addition, this invention is not limited to the structure described in the claim and the structure described in the Example, Of course, a various deformation | transformation is possible without deviating from the technical idea of this invention.

While the embodiments of the present invention have been described above, those skilled in the art will readily understand that additional advantages and modifications are possible in addition to the above-described features and advantages. Accordingly, the invention is not limited to the specific embodiments and representative embodiments described above, and various changes may be made without departing from the spirit or scope of the group of inventive concepts as defined by the appended claims and their equivalents. .

As described above, the present invention selectively irradiates a silicon film on the silicon film of the pixel portion to modify the silicon film, forms a pixel circuit on the modified silicon film, obtains an active matrix substrate, and forms a display device using the same. As a result, a remarkably high performance display device can be provided at a low cost, and the technical and economic effects thereof can be significantly increased.

Claims (21)

An active matrix display device comprising: an active matrix substrate having a modified region modified by selectively irradiating laser light onto a silicon film formed on an insulating substrate, and having an active circuit in the modified region. The method of claim 1, And the active circuit is a pixel circuit in the display region of the active matrix substrate. The method of claim 1, An active matrix display device, wherein said active circuit is a drive circuit provided in a peripheral region of said active matrix substrate. The method of claim 1, And the active circuit is formed of a bottom gate type thin film transistor. The method of claim 1, And the active circuit is a thin film transistor, and the gate of the thin film transistor is formed of a wiring material mainly composed of tungsten or molybdenum. The method of claim 2, And an arrangement pitch of the pixel circuit is equal to a pixel pitch. The method of claim 2, And an arrangement pitch of the pixel circuit is equal to twice the pixel pitch. The method of claim 7, wherein And an arrangement pitch of the pixel circuit and an arrangement pitch of the peripheral circuit are the same. A method of manufacturing an active matrix display device comprising an active matrix substrate having a modified region selectively modified by irradiating laser light onto a silicon film formed on an insulating substrate and having a pixel circuit portion in the modified region, The pixel circuit portion is intensively disposed on the active matrix substrate, and the laser circuit is selectively irradiated and modified to the silicon film of the pixel circuit portion by reciprocating scanning on the intensively arranged portion, and the pixel circuit is applied to the modified silicon film. Forming an active matrix display device. The method of claim 9, And the silicon film of the pixel circuit portion is an amorphous silicon film formed by a CVD method, and the modified silicon film is a polysilicon film. The method of claim 9, And the silicon film of the pixel circuit portion is a polysilicon film modified from an amorphous silicon film, and the modified silicon film is a more modified polysilicon film. The method of claim 9, And the silicon film of the pixel circuit portion is a polysilicon film formed by a sputtering method, and the modified silicon film is a more modified polysilicon film. The method of claim 9, And wherein the silicon film of the pixel circuit portion is a polysilicon film formed by CVD, and the modified silicon film is a more modified polysilicon film. The method of claim 9, And selectively forming a region in which the laser light is irradiated on the active matrix substrate in a stripe shape. The method of claim 9, The silicon film deposited on the active matrix substrate is selectively irradiated with laser light to the silicon film of the pixel circuit portion using a reciprocating operation, and the pixel circuit is formed on the modified silicon film. Method of manufacturing a matrix display device. The method of claim 9, A wavelength of the laser beam is a solid state laser of 400 nm to 2000 nm. The method of claim 9, And a laser for generating the laser light is an excimer laser. The method of claim 9, A method of manufacturing an active matrix display device, wherein the laser beam scanning the active matrix substrate has an irradiation width of 20 µm to 1000 µm. The method of claim 18, The scanning speed of the said laser beam is 1 mm / s-1000 mm / s, The manufacturing method of the active matrix display device characterized by the above-mentioned. The method of claim 18, The laser beam scanning the active matrix substrate is a plurality of laser beams obtained by dividing a single laser beam, and is scanned in parallel using the plurality of laser beams. The method of claim 18, The laser beam scanning the active matrix substrate is a plurality of laser beams in which a plurality of laser oscillators are operated in parallel, and scans in parallel using the plurality of laser beams.