JP2008306043A - Formation method for wiring film, transistor, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a wiring film excellent in adhesiveness and barrier properties, which prevents hillock from being generated. <P>SOLUTION: An added gas containing oxygen or nitrogen is introduced into a vacuum tub 13 in which a film deposition object 21 is arranged, a copper target 11 containing additive elements such as Zr and the like is sputtered, and a barrier film 24 is formed on a surface of an aluminum film 23. Since the barrier film 24 is composed primarily of copper, it can be etched using the same etchant as the aluminum film 23, and since it contains an additive element and oxygen, hillock is not generated on the aluminum film 23. Further, if ITO is brought in close contact with the surface of the wiring film 25, contact resistivity does not become high since the aluminum film 23 does not directly contact the ITO. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to the field of wiring films, and more particularly to a wiring film for transistors and a film forming method for forming the wiring film.

  Conventionally, low resistance materials such as Al and Cu, Mo, Cr, and the like are used for metal wiring films for electronic components. For example, in TFT (Thin Film Transistor) liquid crystal displays, the demand for lower resistance of wiring electrodes is increasing along with the enlargement of the panel, and the need to use Al or Cu as the low resistance wiring is increasing.

  Al wiring used in TFTs has problems such as generation of hillocks in the subsequent process, diffusion problems with the underlying Si layer when used as source / drain electrodes, and deterioration of contact resistance with transparent electrodes made of ITO. In order to avoid them, a barrier layer in which Mo, Cr, Ti and an alloy film containing them as a main component are laminated on the front and rear sides is necessary.

As for Mo, the market demand has been increasing in recent years and the price has been rising. Therefore, there is a demand for a low-cost material that can replace Mo. Regarding Cr, a highly harmful substance is generated by chlorination or sulfuration (such as a hexavalent chromium compound), so a Cr-free material is required for electronic parts.
Regarding Ti, there is a problem that wet etching with a weak acid is difficult. A barrier layer such as TiN or TaN is used for the underlying Cu seed layer of the Cu plating of the semiconductor, but dry etching is mainly used.

In the gate electrode of the TFT, SiNx, a-Si, and the like are stacked in a later process, so that the metal wiring film needs to have a shape with a taper angle. Since the taper angle cannot be controlled by dry etching, wet etching is required. Therefore, a material that can be wet etched with a low cost, harmless substance, and weak acid is required for the barrier layer.
JP-A-6-151432 Japanese Patent Laid-Open No. 2005-33198

  The present invention has been made to solve the above-mentioned problems. The purpose of the present invention is to use Al wiring such as generation of hillocks, diffusion problems with the underlying Si layer, deterioration of contact resistance with the transparent electrode, etc. The present invention provides a technique capable of avoiding the above problem at a low cost without affecting the environment and capable of performing wet etching on an Al wiring.

In the present invention, an aluminum film mainly composed of aluminum in a vacuum atmosphere is formed on the surface of a film formation target, and then oxygen or nitrogen is contained in the chemical structure in the vacuum atmosphere where the film formation target is placed. An additive gas containing any one or both of them is introduced, and in the vacuum atmosphere containing the additive gas, copper or copper as a main component, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co, Ni, Bi, Ag, Zn, Sn, B, C, and Al Sputtering a sputtering target containing at least one additive element selected from the group of additive elements consisting of Si, La, Ce, Pr, Nd, and Mg, and the surface of the aluminum film After forming a barrier film on the aluminum The beam layer and the barrier film is a method of forming a wiring film is etched to form the wiring layer.
The present invention introduces an additive gas containing one or both of oxygen and nitrogen into a chemical structure into a vacuum atmosphere in which a film formation target is placed, and in the vacuum atmosphere containing the additive gas, copper, Alternatively, the main component is copper, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co, Selected from an additive element group consisting of Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd, and Mg Sputtering a sputtering target containing any one or more additive elements, forming an adhesion film on the surface of the film formation target from which silicon or silicon dioxide is exposed, and in the vacuum atmosphere, the adhesion film On the surface of aluminum After forming the film, a method of forming a wiring film forming the wiring film by etching the adhesion film and the aluminum film.
The present invention is a method for forming a wiring film, wherein oxygen gas is used as the additive gas, and the ratio of the oxygen gas partial pressure to the total pressure in the vacuum atmosphere is 0.1% or more and 20.0% or less. The wiring film is formed by sputtering the sputtering target in which the oxygen gas is introduced and Zr is contained in an amount of 0.1 atomic% or more and 20.0 atomic% or more.
The present invention includes a gate electrode and a drain semiconductor layer and a source semiconductor layer each made of a semiconductor, and the drain semiconductor layer and the source semiconductor layer are blocked or conducted by a voltage applied to the gate electrode. An aluminum film mainly composed of aluminum is connected to one or both of the drain semiconductor layer and the source semiconductor layer, and copper or copper is formed on the surface of the aluminum film. Is the main component, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co, Ni, Any one selected from the group of additive elements consisting of Bi, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd, and Mg Various additive elements and oxygen or Either or barrier layer both are contained in the nitrogen is arranged transistors.
The present invention includes a gate electrode and a drain semiconductor layer and a source semiconductor layer each made of a semiconductor, and the drain semiconductor layer and the source semiconductor layer are blocked or conducted by a voltage applied to the gate electrode. The surface of one or both of the drain semiconductor layer and the source semiconductor layer is composed of copper or copper as a main component, Ti, Zr, Hf, V, and Nb. , Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co, Ni, Bi, Ag, Zn, Sn, B, C, and Al , Si, La, Ce, Pr, Nd, and any one kind of additive element selected from the additive element group consisting of Mg and either or both of oxygen and nitrogen were contained An adhesion film is disposed on the surface of the adhesion film Aluminum film mainly is arranged transistor aluminum.
The present invention has a gate electrode, a drain semiconductor layer made of a semiconductor, and a source semiconductor layer made of a semiconductor, and the voltage applied to the gate electrode interrupts the drain semiconductor layer and the source semiconductor layer. Or a transistor configured to be conductive, wherein the gate electrode is disposed on a surface of the aluminum film containing aluminum as a main component and the aluminum film, copper or copper as a main component, and Ti , Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co, Ni, Bi, Ag, Zn And any one element selected from the group of additive elements consisting of Sn, B, C, Al, Si, La, Ce, Pr, Nd, and Mg, and oxygen Or one or both of nitrogen There is a transistor having a barrier film that is contained.
The present invention has a gate electrode in contact with a glass substrate, a drain semiconductor layer made of a semiconductor, and a source semiconductor layer made of a semiconductor, and the drain semiconductor layer and the source semiconductor layer are applied with a voltage applied to the gate electrode. The gate electrode is composed of an adhesion film that is in contact with the glass substrate, and aluminum that is mainly composed of aluminum and disposed on the surface of the adhesion film. The adhesion film is made of copper or copper as a main component, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, and the like. Fe, Ru, Os, Co, Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd And selected from the group of additive elements consisting of Mg And one kind of additive elements, either or both of the oxygen or nitrogen is the transistors contained.
The present invention is an electronic device having the transistor.
The present invention provides a glass substrate, a transparent pixel electrode disposed on the glass substrate, a liquid crystal disposed on the pixel electrode, a transparent common electrode disposed on the liquid crystal, and the glass substrate. A storage capacitor having a storage electrode in close contact with each other and connected to a liquid crystal capacitor formed between the pixel electrode and the storage electrode, the storage electrode having the storage electrode on one side is connected. An electronic device in which the orientation of liquid crystal is controlled, wherein the storage electrode includes an aluminum film disposed on the glass substrate and a barrier film disposed on a surface of the aluminum film, Aluminum as a main component, and the barrier film is copper or copper as a main component, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn Fe, Ru, Os, From the additive element group consisting of o, Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd, and Mg This is an electronic device containing any one selected additive element and either or both of oxygen and nitrogen.
The present invention provides a glass substrate, a transparent pixel electrode disposed on the glass substrate, a liquid crystal disposed on the pixel electrode, a transparent common electrode disposed on the liquid crystal, and the glass substrate. A storage capacitor having a storage electrode in close contact with each other and connected to a liquid crystal capacitor formed between the pixel electrode and the storage electrode, the storage electrode having the storage electrode on one side is connected. An electronic device in which the orientation of liquid crystal is controlled, wherein the storage electrode has an adhesion film that is in close contact with the glass substrate, and an aluminum film that is disposed on a surface of the adhesion film, and the aluminum film is made of aluminum. The adhesive film is mainly composed of copper or copper, and Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe Ru, Os, Co, Ni, Any one selected from an additive element group consisting of i, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd, and Mg It is an electronic device containing various kinds of additive elements and either or both of oxygen and nitrogen.

In the present invention, a pure copper target made of copper or a copper target containing copper as a main component and added with the above additive elements is used as a sputtering target. In this invention, a main component is containing 50 mass% or more of copper.
Elements other than copper may be mixed in the pure copper target as impurity elements. In addition, an element other than the additive element may be mixed as an impurity element in the copper target.
In both cases of the pure copper target and the copper target, the content of the impurity element is less than 0.1 atomic%, usually less than 10 ⁻⁴ atomic%.

Therefore, the wiring film formed by sputtering a pure copper target has a content of impurity elements other than Cu and oxygen or / and nitrogen of less than 0.1 atomic%, usually less than 10 ⁻⁴ atomic%, In the wiring film formed by sputtering the target, the content of Cu, oxygen or / and nitrogen, and impurity elements other than additive elements is less than 0.1 atomic%, usually less than 10 ⁻⁴ atomic%. .

  The wiring film formed according to the present invention has high adhesion to silicon and glass, does not cause copper diffusion to silicon, and has low resistance. Since the barrier film, the aluminum film, and the adhesion film can be patterned at the same time using the same etchant, the manufacturing process is simple. Since wet etching is possible with a weak acid, it is possible to give the wiring film a taper angle shape. Since the barrier film and the adhesion film are mainly composed of copper, the cost is low.

  The sputtering apparatus for forming the adhesion film and the barrier film of the present invention is an apparatus having the same structure, and the same members will be described with the same reference numerals.

Referring to FIG. 1, a sputtering apparatus 1 for an adhesion film and a sputtering apparatus 2 for a barrier film have a vacuum chamber 13.
Here, in the vacuum chamber 13, the copper target 11 containing copper as a main component and containing an additive element is disposed. However, either or both of the copper target 11 and the pure copper target are disposed. Also good.
The additive elements are Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co, Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, One or more additive elements in the additive element group of La, Ce, Pr, Nd, and Mg.

An evacuation system 9 and a gas introduction system 8 are connected to the vacuum chamber 13. The vacuum chamber 13 is evacuated by the vacuum evacuation system 9, and the film formation target 21 is carried in a vacuum atmosphere. The substrate holder 7 disposed in the vacuum chamber 13 is held.
A sputtering gas source and an oxygen gas source are connected to the gas introduction system 8 so that the sputtering gas and the oxygen gas can be introduced into the vacuum chamber 13 while controlling the flow rate.

A sputtering power source 5 is connected to the copper target 11. After the vacuum chamber 13 is evacuated, sputtering gas or sputtering gas and oxygen gas are introduced from the gas introduction system 8. When a voltage is applied, plasma of the gas introduced near the surface of the copper target 11 is formed.
When the copper target 11 is sputtered by the plasma, the particles of the material constituting the copper target 11 are emitted toward the film formation target 21 and reach the surface of the film formation target 21. A thin film is formed.

A process of manufacturing the liquid crystal display device of the present invention in which an adhesion film, an Al film, and a barrier film are laminated using the sputtering apparatuses 1 and 2 will be described.
First, when the inside of the vacuum chamber 13 of the sputtering apparatus 1 for adhesion film is made into a vacuum atmosphere, the film formation target 21 is carried in, and the copper target 11 is sputtered while introducing the sputtering gas and the oxygen gas, the film formation target 21 An adhesion film 22 made of a metal film containing copper as a main component and containing oxygen and additive elements is formed on the surface (FIG. 2A).

  When the adhesion film 22 is formed to a predetermined film thickness, it is unloaded from the adhesion film sputtering apparatus 1 and an Al target made of pure Al or an Al target containing Al as a main component and other elements such as Si added. When a sputtering gas is introduced and a sputtering target is sputtered, an Al target is sputtered on the surface of the adhesion film 22 as shown in FIG. Thus, an aluminum film 23 made of an Al alloy to which other elements such as Si are added is formed.

After the aluminum film 23 is formed to a predetermined thickness, the film formation target 21 is unloaded from the Al film sputtering apparatus and is loaded into the barrier film sputtering apparatus 2.
When sputtering gas and oxygen gas are introduced into the vacuum chamber 13 of the sputtering apparatus 2 for the barrier film and the copper target 11 is sputtered, copper is a main component on the surface of the aluminum film 23 as shown in FIG. Then, a barrier film 24 made of a metal film containing oxygen and an additive element is formed.

When the barrier film 24 is formed to a predetermined thickness, the film formation target 21 is unloaded from the barrier film sputtering apparatus 2.
The sputtering apparatus 2 for the barrier film and the sputtering apparatus 1 for the adhesion film may be used in common, and the barrier film 24 may be formed in the same sputtering apparatus 1 in which the adhesion film 22 is formed. The film 24 may be formed by another sputtering apparatus 1 or 2.

Next, as shown in FIG. 2D, a patterned resist film 26 is disposed on the surface of the barrier film 24, and the barrier film 24 exposed on the bottom surface of the resist film 26 is exposed to an etching solution or an etching gas.
Since the adhesion film 22 and the barrier film 24 are mainly composed of copper, the adhesion film 22 and the barrier film 24 can be etched with a weak acid, and the same etching solution (or etching gas) as that used to etch the aluminum film 23 is used. The metal film in which the aluminum film 23 and the barrier film 24 are stacked can be etched.

Accordingly, as shown in FIG. 2E, the adhesion film 22, the aluminum film 23, and the barrier film 24 are patterned by the same resist film 26 by one etching, and the wiring film 25 is obtained. The wiring film 25 has a three-layer structure including an adhesion film 22, an aluminum film 23, and a barrier film 24.
The cross-sectional shape of the wiring film 25 is a trapezoid whose width on the bottom side is longer than the width of the upper part, and has a taper.

  When the film formation target 21 is a panel of a liquid crystal display device, the surface of the glass substrate or the surface of a semiconductor layer such as silicon is exposed on part or all of the surface of the film formation target 21. When the film target 21 is a semiconductor device such as an integrated circuit, the surface of a semiconductor substrate or semiconductor layer such as silicon is exposed on a part or all of the surface of the film target 21.

The adhesion between the adhesion film 22 and the glass substrate or silicon layer is higher than the adhesion between the aluminum film 23 and the glass substrate or silicon layer.
Since the adhesion film 22 and the aluminum film 23 are metal films and the adhesion between them is high, the aluminum film 23 is firmly connected to the glass substrate surface or the silicon layer surface by the adhesion film 22 and is difficult to peel off.

Further, a barrier film 24 containing an additive element and oxygen is disposed on the surface of the aluminum film 23, thereby preventing hillocks in the aluminum film 23. (Conventionally, the aluminum film 23 is prone to hillocks, and a refractory metal film is disposed on the surface of the aluminum film 23 in order to prevent hillocks. (It is necessary to perform etching in a process different from that of 23.)
In the present invention, the wiring film used for the electrode of the TFT is in contact with an oxide transparent conductive film such as ITO and is electrically connected to the oxide transparent conductive film. Since oxygen is contained in the barrier film, oxygen in the oxide transparent conductive film does not diffuse into the barrier film, and connection failure does not occur. (If a current is passed in a state where the oxide transparent conductive film such as ITO and the metal film are in contact with each other, oxygen in the oxide transparent conductive film may diffuse into the metal film, resulting in poor connection).

Next, the electronic device of the present invention will be described. Reference numeral 3 in FIG. 3 is a liquid crystal display device which is an example of the electronic device of the present invention, and includes a TFT substrate 30 and a color filter substrate 50.
The liquid crystal display device 3 is an active type, and the TFT substrate 30 has a glass substrate 31, and the TFT 40, the display pixel 35, and the storage capacitor 39 are disposed on the glass substrate 31.

The TFT 40 has a gate electrode 41, a source electrode 42, and a drain electrode 43, the storage capacitor 39 has a storage electrode 38, and the display pixel 35 has a pixel electrode 36.
Any one or all of the gate electrode 41, the source electrode 42, the drain electrode 43, and the storage electrode 38 are constituted by the wiring film 25.

The TFT 40 includes a gate insulating film 44, a channel semiconductor layer 46, a source semiconductor layer 47, and a drain semiconductor layer 48.
A source semiconductor layer 47 and a drain semiconductor layer 48 are arranged in contact with each other on one side of the channel semiconductor layer 46, and the gate electrode 41 is a source semiconductor layer on the opposite side of the channel semiconductor layer 46. The gate insulating film 44 is disposed between the gate electrode 41 and the channel semiconductor layer 46.

  The drain electrode 43 and the source electrode 42 are disposed in contact with the surfaces of the drain semiconductor layer 48 and the source semiconductor layer 47, respectively. The gate electrode 41, the source electrode 42, and the drain electrode 43 are led out of the TFT 40, and a voltage from an external power source can be applied.

  Here, the channel semiconductor layer 46 has the same conductivity type as the source and drain semiconductor layers 47 and 48, but has a lower impurity concentration than the source and drain semiconductor layers 47 and 48, and the drain electrode 43 and the source electrode 42. When a voltage is applied to the gate electrode 41 in a state where an operating voltage is applied to the gate electrode 41, a low-resistance storage layer is formed in a portion of the channel semiconductor layer 46 that contacts the gate electrode 41 through the gate insulating film 44. The drain semiconductor layer 48 and the source semiconductor layer 47 are electrically connected through the layer, and the TFT 40 becomes conductive.

  The channel semiconductor layer 46 may have a conductivity type opposite to that of the source and drain semiconductor layers 47 and 48. In this case, when an operating voltage is applied to the drain electrode 43 and the source electrode 42, when a voltage is applied to the gate electrode 41, the source of the channel semiconductor layer 46 in contact with the gate electrode 41 through the gate insulating film 44 is And the inversion layer of the same conductivity type as the drain semiconductor layers 47 and 48 is formed, the drain semiconductor layer 48 and the source semiconductor layer 47 are electrically connected by the inversion layer, and the TFT 40 becomes conductive.

A part of the surface of the drain electrode 43 or the source electrode 42 is exposed, and a pixel electrode 36 extending from the display pixel 35 is in contact therewith. Here, the source electrode 42 is connected to the pixel electrode 36.
The pixel electrode 36 extends to a portion where the storage capacitor 39 is located, and is disposed to face the storage electrode 38 disposed on the glass substrate 31 via an insulating film (gate insulating film) 44. A storage capacitor is formed by the portion.

The TFT substrate 30 and the color filter substrate 50 are spaced apart from each other by a predetermined distance, and the liquid crystal 4 is sealed therebetween.
On the color filter substrate 50, a black matrix 52 is disposed at a position facing the TFT 40, and a color filter 53 is disposed at a position facing the display pixel 35.
A common electrode 55 is disposed on at least a portion of the color filter substrate 50 facing the display pixel 35.

The pixel electrode 36 and the common electrode 55 are made of a transparent conductive film such as ITO.
The TFT substrate 30 and the color filter substrate 50 have polarizing plates 49 and 59, respectively. When a voltage is applied between the pixel electrode 36 and the common electrode 55 due to the conduction and interruption of the TFT 40, the orientation of the liquid crystal 4 on the display pixel 35 changes, the deflection direction of the light passing through the liquid crystal 4 is changed, and the display Transmission and blocking of the light irradiated to the pixels 35 to the outside of the liquid crystal display device 3 are controlled.

  The storage capacitor is connected in parallel to the liquid crystal capacitor formed between the pixel electrode 36 and the common electrode 55, the TFT 40 becomes conductive, and the capacitor between the pixel electrode 36 and the common electrode 55 passes through the TFT 40. When the battery is charged with the power supply voltage, the storage capacitor is also charged with the power supply voltage.

  Even if the TFT 40 is turned off due to the charge accumulated in the storage capacitor and the pixel electrode 36 is cut off from the power supply voltage, the same voltage as that when the TFT 40 is turned on is applied to the pixel electrode 36, and the liquid crystal 4 on the display pixel 35 The deflection state is maintained. When this liquid crystal capacitance is discharged, the deflection state of the liquid crystal 4 changes.

The storage electrode 38 and the gate electrode 41 are in contact with the glass substrate 31, and the source electrode 42 and the drain electrode 43 are in contact with the semiconductor layers (source semiconductor layer 47 and drain semiconductor layer 48).
The source electrode 42 and the drain electrode 43 are formed by patterning the same thin film. The gate electrode 41 and the storage electrode 38 are also formed by patterning the same thin film.

The storage electrode 38, the gate electrode 41, the source electrode 42, and the drain electrode 43 are composed of the wiring film 25 formed according to the present invention, and the adhesion film 22 is in contact with the glass substrate 31 or the semiconductor layers 47 and 48. ing.
Therefore, the adhesiveness between the storage electrode 38 and the gate electrode 41 and the glass substrate 31 and the adhesiveness between the source electrode 42 and the drain electrode 43 and the semiconductor layers 47 and 48 are high, and is disposed on the adhesive film 22. Since the aluminum film 23 does not contain oxygen and has low resistance, the spreading direction of each electrode film (direction perpendicular to the film thickness direction) has low resistance.

When a metal oxide film (pixel electrode 36) such as ITO or ZnO is in close contact with the surface like the source electrode 42 of the liquid crystal display device 3, the source electrode 42 is formed by the wiring film forming method of the present invention. If the pixel electrode 36 is brought into close contact with the surface of the barrier film 24, oxygen migration from the pixel electrode 36 to the source electrode 42 does not occur, and the aluminum film 23 is not oxidized, so that the electrical resistance (contact resistance) of the source electrode 42 increases. do not do.
The electronic device of the present invention is not limited to a liquid crystal display device.
Reference numeral 6 in FIG. 4 is a part of a semiconductor device which is another example of the electronic device of the present invention. FIG. 4 shows a transistor 60 of the semiconductor device 6.
The transistor 60 has the same member as the TFT 40 shown in FIG. 3 except that it is not disposed on a glass substrate and has a semiconductor substrate (silicon substrate) 61, and the same members are denoted by the same reference numerals. The description is omitted.

  Also in this transistor 60, the partial surfaces of the source semiconductor layer 47 and the drain semiconductor layer 48 are exposed. The source electrode 42 and the drain electrode 43 are formed in the steps shown in FIGS. 2A to 2E, and the exposed film 22 of the source electrode 42 is formed on the exposed portions of the source semiconductor layer 47 and the drain semiconductor layer 48. The adhesion films 22 of the drain electrode 43 are in close contact with each other. Therefore, the adhesion of the drain electrode 43 and the source electrode 42 to the silicon substrate 61 is high, and the adhesion film 22 prevents Al diffusion into the silicon substrate 61.

  4 is an insulating film for insulating the drain electrode 43 and the source electrode 42 from the gate electrode 41, and reference numeral 74 in FIG. 4 indicates that the drain electrode 43 and the source electrode 42 are the source of the silicon substrate 61. This is an insulating film for insulating from a place other than the semiconductor layer 47 and the drain semiconductor layer 48.

The above describes the case where the source electrode 42, the drain electrode 43, the gate electrode 41, and the storage electrode 38 are formed by sputtering the copper target 11 containing the additive element, but the present invention is limited to this. Instead, at least one of the source electrode 42, the drain electrode 43, the gate electrode 41, and the storage electrode 38 may be formed by sputtering only a pure copper target.
Furthermore, both the pure copper target and the copper target 11 may be simultaneously sputtered inside the same vacuum chamber to form electrodes.

  Further, the source electrode 42, the drain electrode 43, the gate electrode 41, and the storage electrode 38 are formed by the wiring film forming method of the present invention, but either or both of the source electrode 42 and the drain electrode 43 are formed of the wiring film of the present invention. The gate electrode 41 and the storage electrode 38 may be formed by a method different from that of the present invention, and either or both of the gate electrode 41 and the storage electrode 38 may be formed by the method of forming the wiring film of the present invention. The source electrode and the drain electrode may be formed by a method different from the present invention.

Moreover, although the above has arrange | positioned the contact | adherence film | membrane 22 between the glass substrate 31 or the semiconductor layers 47 and 48, and the aluminum film 23, when intensity | strength is enough even if it forms the aluminum film 23 directly on the glass substrate 31 surface etc. As shown in FIG. 5, a wiring film 27 having a two-layer structure of an aluminum film 23 and a barrier film 24 can be used without providing the adhesion film 22. Also when the wiring film 27 having a two-layer structure is formed, the aluminum film 23 and the barrier film 24 can be etched once with the same etching solution and patterned with the same resist layer.
Further, after the aluminum film 23 is formed on the surface of the adhesion film 22, the insulating film (for example, the gate insulating film 44) or the pixel electrode 36 may be in direct contact with the surface of the aluminum film 23 without providing the barrier film 24. Good.

The above has described the case where oxygen gas (O ₂ ) is introduced into the vacuum chamber 13 when forming the adhesion film 22 and the barrier film 24, but the present invention is not limited to this, and NO, NO ₂ , one or more additive gases selected from the additive gas group consisting of O ₂ , N ₂ , and H ₂ O are introduced into the vacuum chamber 13 to perform sputtering, and either or both of oxygen and nitrogen are used. Either or both of the adhesion film 22 and the barrier film 24 may be constituted by the metal film to be contained.

The drain semiconductor layer 48, the source semiconductor layer 47, and the channel semiconductor layer 46 are formed by diffusing impurities in the silicon substrate 61 when the electronic device is the semiconductor device 6, and when the electronic device is a liquid crystal display device. Is formed by depositing a semiconductor such as silicon on the surface of the glass substrate 31 by a CVD method or the like.
The insulating film such as the gate insulating film 44 is formed of a nitride film such as silicon nitride or an oxide film such as silicon oxide.
The TFT 40 of the present invention can be used for other electronic devices such as an organic EL display in addition to the liquid crystal display device 3.

<Adhesion test>
After the aluminum film 23 is formed on the surface of the glass substrate, the content of the additive element (Zr) in the copper target 11, the ratio of the oxygen gas partial pressure during sputtering to the total pressure, and the temperature of the annealing treatment after film formation are formed. The film conditions were combined, and a barrier film 24 (target film thickness of 300 nm) was formed on the surface of the aluminum film 23 in each combination.

  The adjustment of the oxygen gas partial pressure is such that when the amount of oxygen gas introduced is zero and only the sputtering gas (Ar) is introduced, the amount of sputtering gas introduced is such that the total pressure inside the vacuum chamber 13 is 0.4 Pa. Was set, and the introduction amount of the oxygen gas was changed without changing the introduction amount of the sputtering gas. That is, the partial pressure of the sputtering gas (Ar) in each combination was 0.4 Pa.

  Each barrier film 24 is cut into a 1 mm square cell with 10 rows × 10 columns and a total of 100 notches using a cutter knife with a sharp tip, and an adhesive tape (model No. 610 Scotch tape) is attached, and then the adhesive tape is attached. When peeled, the number of barrier films 24 remaining on the surface of the aluminum film 23 on the glass substrate was counted. The results are shown in Table 1 below together with combinations of the Zr content, the ratio of the oxygen gas partial pressure, and the film forming conditions of the annealing temperature.

When the barrier film 24 is completely peeled off, it becomes 0/100, and when no barrier film 24 is peeled off, it becomes 100/100. The larger the number of molecules, the higher the adhesion of the barrier film 24.
From Table 1 above, even when the Zr content is the same, the higher the oxygen gas ratio, the higher the adhesion, and even when the oxygen gas ratio is the same, the higher the Zr content, the higher the adhesion. Is high.

If the Zr content of the copper target 11 is 0.1 atomic% or more and the oxygen ratio is 3.0% or more, peeling of the metal film does not occur. Therefore, the Zr content of the copper target 11 is from 0.1 atomic%. At least, if the amount of oxygen gas introduced exceeds 3.0% during sputtering, it is presumed that no metal film occurs.
Further, when the content of Zr in the copper target 11 is zero (pure copper target), if the oxygen ratio is less than 10%, the adhesion is impure, but if the oxygen ratio exceeds 10%, it is practically sufficient. Adhesiveness was obtained.

<Barrier properties>
The silicon substrate was washed with a cleaning solution (BHF: buffered hydrofluoric acid solution), rinsed with pure water, and dried (cleaning treatment).
A copper target 11 containing Zr is sputtered in a vacuum atmosphere containing oxygen to form an adhesion film 22 having a thickness of 50 nm on the surface of the silicon substrate after the cleaning treatment, and then the surface of the adhesion film 22 An aluminum film 23 was formed thereon to form a metal film having a two-layer structure.

Separately, the aluminum film 23 was formed in close contact with the surface of another silicon substrate after the cleaning treatment without providing the contact film 22.
The silicon substrate with the aluminum film 23 formed on the surface and the silicon substrate with the adhesion film 22 and the aluminum film 23 laminated on the surface were heated in a vacuum atmosphere at 300 ° C. for 1 hour, and then each metal film was etched. The removed and exposed silicon substrate surface was observed with an electron microscope.
FIG. 6 shows an electron micrograph of the surface of the silicon substrate after removing the closely formed aluminum film 23, and the electrons on the surface of the silicon substrate after removing the metal film (Al film, Cu, Zr film) having a two-layer structure. A photomicrograph is shown in FIG.

  6 and 7, H pits (dents) are seen in FIG. 6, but no H pits are seen in FIG. Accordingly, it can be seen that diffusion is prevented by providing the adhesion film 22 between the aluminum film 23 and the silicon substrate without causing the aluminum film 23 to adhere to the silicon substrate.

<Hillock prevention>
A substrate having an aluminum film 23 formed on the surface is used as a film formation target, and the copper target 11 containing Zr is sputtered in a vacuum atmosphere containing oxygen to form a barrier film 24 on the surface of the aluminum film 23. Was deposited.
The substrate with the aluminum film 23 exposed on the surface without forming the barrier film 24 and the substrate with the barrier film 24 formed on the surface of the aluminum film 23 were heated at 350 ° C. for 1 hour, and then the surface state was changed. Observed with an electron microscope.

  FIG. 8 is an electron micrograph of the surface of the aluminum film 23 after heat treatment of the substrate with the aluminum film 23 exposed on the surface, and FIG. 9 shows a state in which the barrier film 24 is formed on the surface of the aluminum film 22. 2 is an electron micrograph of the metal film surface (barrier film 24 surface) after heat treatment of the substrate.

As apparent from FIG. 8, the hillock (crystal growth) was observed in the aluminum film 23 having no barrier film formed on the surface, but the aluminum film 23 was covered with the barrier film 24. No hillocks were seen.
From the above, it can be seen that hillocks can be prevented if the surface of the aluminum film 23 is covered with a barrier film 24 containing copper as a main component, an additive element, and oxygen (or / and nitrogen).

<Etching rate measurement>
Etching rate for metal film (CuZr film) formed by sputtering a copper target containing Zr in a vacuum atmosphere containing oxygen and other metal films (Al film, Mo film, Ti film, Ta film) It was measured.
The etchant used was an etching solution in which FeCl ₃ : H ₂ O was mixed at a ratio of 1:10 (weight ratio) and heated to 40 ° C. This is a weak acid etchant widely used in wet etching.

  The measured etching rate is shown in FIG. 10 as a bar graph for each type of metal film. As shown in FIG. 10, although Ti and Ta were not etched and Mo was etched, the difference between the etching rate and the etching rate of the Al film is the difference between the etching rate of the Al film and the etching rate of the CuZr film. It can be seen that the Al film and the Mo film cannot be etched together with a weak acid etchant.

<ITO contact resistance>
The copper target 11 is sputtered while introducing oxygen gas, the adhesion film 22 is formed on the surface of the glass substrate, the ITO film is formed in close contact with the surface of the adhesion film 22, and the ITO film and adhesion film are formed before and after the annealing treatment. A resistance value between 22 was measured. The annealing temperature was 250 ° C. and the ITO film thickness was 150 nm.
The relationship between the additive element (Zr) content in the copper target 11 and the resistance value is shown in Table 2 below.

  As a comparative example, an aluminum target was formed by sputtering an aluminum target instead of a copper target, and an ITO film was formed on the surface of the aluminum film as in the case of the adhesion film 22, before and after the annealing treatment. Then, the resistance value between the ITO film and the aluminum film was measured, and the measurement results are shown in Table 2 above.

As apparent from Table 2 above, the adhesion film 22 formed by sputtering the copper target had a lower resistance value with the ITO film than the aluminum film.
In particular, when the copper target contains 0.1 atomic% or more and 10.0 atomic% or less of Zr, the resistance value after annealing was smaller.

Sectional drawing for demonstrating an example of the sputtering device used for this invention (A)-(e): Sectional drawing for demonstrating an example of the formation process of the wiring film of this invention Sectional drawing for demonstrating an example of the electronic device of this invention Sectional drawing for demonstrating the other example of the electronic device of this invention Sectional drawing for demonstrating the other example of the wiring film formed into a film by this invention Electron micrograph of silicon substrate surface with Al film An electron micrograph of the surface of a silicon substrate to which a CuZr film is adhered Electron micrograph of Al film surface without barrier film Electron micrograph of Al film surface with barrier film Etch rate graph

Explanation of symbols

  3 ... Liquid crystal display device 6 ... Semiconductor device 11 ... Copper target 22 ... Adhesion film 23 ... Aluminum film 24 ... Barrier film 25, 27 ... Wiring film 36 ... Pixel electrode 38 ... Storage electrode 40 ... ... Transistor (TFT) 41 ... Gate electrode 42 ... Source electrode 43 ... Drain electrode 46 ... Channel semiconductor layer 47 ... Source semiconductor layer 48 ... Drain semiconductor layer 55 ... Common electrode

Claims (10)

After forming an aluminum film mainly composed of aluminum in a vacuum atmosphere on the surface of the object to be deposited,
Introducing an additive gas containing one or both of oxygen and nitrogen into the chemical structure in a vacuum atmosphere where the film formation target is placed,
In the vacuum atmosphere containing the additive gas, copper or copper as a main component, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn and Fe, Ru, Os, Co, Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd And sputtering a sputtering target containing any one or more additive elements selected from the additive element group consisting of Mg, and after forming a barrier film on the surface of the aluminum film,
A wiring film forming method of forming a wiring film by etching the aluminum film and the barrier film. An additive gas containing one or both of oxygen and nitrogen in the chemical structure is introduced into the vacuum atmosphere where the film formation target is placed,
In the vacuum atmosphere containing the additive gas, copper or copper as a main component, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn and Fe, Ru, Os, Co, Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd And sputtering a sputtering target containing one or more additional elements selected from the additive element group consisting of Mg, and an adhesion film is formed on the surface of the film formation target where silicon or silicon dioxide is exposed. Closely formed,
After forming an aluminum film mainly composed of aluminum on the surface of the adhesion film in the vacuum atmosphere,
A wiring film forming method of forming a wiring film by etching the aluminum film and the adhesion film. Using oxygen gas as the additive gas,
Introducing the oxygen gas so that the ratio of the partial pressure of oxygen gas to the total pressure of the vacuum atmosphere is 0.1% or more and 20.0% or less;
The method for forming a wiring film according to claim 1, wherein the sputtering target containing Zr of 0.1 atomic% or more and 20.0 atomic% or more is sputtered. A gate electrode;
Each has a drain semiconductor layer and a source semiconductor layer made of a semiconductor,
The voltage applied to the gate electrode is configured to block or conduct between the drain semiconductor layer and the source semiconductor layer,
An aluminum film containing aluminum as a main component is connected to one or both of the drain semiconductor layer and the source semiconductor layer,
On the surface of the aluminum film, copper or copper as a main component, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe Ru, Os, Co, Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd, A transistor in which a barrier film containing any one kind of additive element selected from the additive element group consisting of Mg and one or both of oxygen and nitrogen is disposed. A gate electrode;
Each has a drain semiconductor layer and a source semiconductor layer made of a semiconductor,
The voltage applied to the gate electrode is configured to block or conduct between the drain semiconductor layer and the source semiconductor layer,
On the surface of one or both of the drain semiconductor layer and the source semiconductor layer, copper, or copper as a main component, Ti, Zr, Hf, V, Nb, Ta, and Cr , Mo, W, Mn, Fe, Ru, Os, Co, Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, and La And an adhesion film containing any one kind of additive element selected from the additive element group consisting of Ce, Pr, Nd, and Mg, and one or both of oxygen and nitrogen,
A transistor in which an aluminum film mainly composed of aluminum is disposed on a surface of the adhesion film. A gate electrode;
A drain semiconductor layer made of a semiconductor;
A source semiconductor layer made of a semiconductor,
A transistor configured to cut off or conduct between the drain semiconductor layer and the source semiconductor layer with a voltage applied to the gate electrode;
The gate electrode includes an aluminum film mainly composed of aluminum;
Arranged on the surface of the aluminum film,
Copper or copper as the main component, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co , Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd, and Mg. And a barrier film containing either one or both of oxygen and nitrogen. A gate electrode in contact with the glass substrate;
A drain semiconductor layer made of a semiconductor;
A source semiconductor layer made of a semiconductor,
A transistor configured to cut off or conduct between the drain semiconductor layer and the source semiconductor layer with a voltage applied to the gate electrode;
The gate electrode has an adhesion film that contacts the glass substrate;
It has aluminum as a main component and an aluminum film disposed on the surface of the adhesion film,
The adhesion film is mainly composed of copper or copper, and includes Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, and Ru. , Os, Co, Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd, and Mg A transistor containing any one type of additive element selected from the group of additive elements and one or both of oxygen and nitrogen.   An electronic device comprising the transistor according to claim 4. A glass substrate, a transparent pixel electrode disposed on the glass substrate, a liquid crystal disposed on the pixel electrode, a transparent common electrode disposed on the liquid crystal, and an accumulation closely attached to the glass substrate Having electrodes,
A storage capacitor having the storage electrode on one side is connected to a liquid crystal capacitor formed between the pixel electrode and the storage electrode,
An electronic device in which the alignment of the liquid crystal is controlled by charging and discharging the liquid crystal capacity,
The storage electrode has an aluminum film disposed on the glass substrate, and a barrier film disposed on the surface of the aluminum film,
The aluminum film is mainly composed of aluminum,
The barrier film is mainly composed of copper or copper, and includes Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, and Ru. , Os, Co, Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd, and Mg An electronic device containing any one type of additive element selected from the group of additive elements and one or both of oxygen and nitrogen. A glass substrate, a transparent pixel electrode disposed on the glass substrate, a liquid crystal disposed on the pixel electrode, a transparent common electrode disposed on the liquid crystal, and an accumulation closely attached to the glass substrate Having electrodes,
A storage capacitor having the storage electrode on one side is connected to a liquid crystal capacitor formed between the pixel electrode and the storage electrode,
An electronic device in which the alignment of the liquid crystal is controlled by charging and discharging the liquid crystal capacity,
The storage electrode has an adhesion film in close contact with the glass substrate, and an aluminum film disposed on the surface of the adhesion film,
The aluminum film is mainly composed of aluminum,
The adhesion film is mainly composed of copper or copper, and includes Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, and Ru. , Os, Co, Ni, Bi, Ag, Zn, Sn, B, C, Al, Si, La, Ce, Pr, Nd, and Mg An electronic device containing any one type of additive element selected from the group of additive elements and one or both of oxygen and nitrogen.