JPH0594960A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide a densely integrated circuit where connection failure caused by particles is prevented from occurring between an element and a metal wiring layer or between metal wiring layers, and wirings are enhanced in processing accuracy. CONSTITUTION:A contact window 8 is provided to an interlayer insulating film on a semiconductor substrate facing towards the signal connection section of an element, the exposed silicon surface is treated with oxidizing solution for the formation of a thin protective oxide film 1, then a reducing metal film 110 of titanium is deposited thereon, a wiring multilayered metal film composed of a high-melting metal film 111 of titanium or tungsten and an aluminum alloy film 112 is deposited overlapping, an electrode is formed through a photo- etching method, and then the wiring multilayered metal film is turned into allay through a heat treatment, and a thin film protective oxide film is reduced and eliminated. By this setup, particles are prevented from attaching, whereby a contact resistance is kept well. The forming method where the same protective film as above is formed can be applied to the viahole of a semiconductor device provided with a multilayered metal wiring layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device having a high-density integrated circuit, and more particularly to a measure for preventing connection failure in a contact hole or a via hole.

[0002]

2. Description of the Related Art In recent years, high density and high integration of MOS integrated circuit devices have been advanced, and for example, a dynamic RAM has been reported to have a minimum size of 0.5 micron and a large capacity of 16 megabits or more. However, as one of the challenges for miniaturization, there is an improvement in fine processing technology for electrodes and metal wiring. In particular, metal wiring represented by an aluminum alloy is difficult to miniaturize, and there are many technical problems in forming electrodes and metal wiring in a submicron pattern. This is mainly due to the instability of connection in the contact holes of the aluminum alloy film and the generation of defects due to particle adhesion during vapor deposition of the aluminum alloy film and barrier metal.

Here, a conventional electrode forming method for a semiconductor integrated circuit device will be described with reference to FIGS. 3 and 4.

FIGS. 3A and 3B show an electrode forming method of a semiconductor device in which one layer of aluminum wiring is used for extracting electrodes, and a portion for extracting electrodes from a diffusion layer formed on a semiconductor substrate, respectively. 3 is a partial process cross-sectional view of the CMOS integrated circuit device showing FIG. In FIG. 3A, 10
1 is a P-type silicon substrate, and 102a is a silicon substrate 101.
, A P-type well region formed on the main surface of the same, 102b is an N-type well region, 103 is an element isolation region made of a silicon dioxide film, 104a and 104b are gate oxide films, and 105
a and 105b are gate electrodes made of polysilicon, 10
6a is an N-type impurity diffusion layer formed in the P-type well region 102a, 106b is a P-type impurity diffusion layer formed in the N-type well region 102b, and 107 is an interlayer insulating film. Further, in FIG. 3B, 8 is the interlayer insulating film 107.
The contact hole is formed on the silicon substrate and is an extraction port from the impurity diffusion layers 106a and 106b formed on the silicon substrate. Then, a titanium-tungsten film 111 which is a refractory metal film and an aluminum alloy film 112 are sequentially deposited on the substrate after the contact holes 8 are opened by a well-known sputter deposition method, and then the electrodes are formed by a well-known photo-etching method. Pattern is formed, and further, each metal film 111, 11 is formed.
Perform the sintering process of 2. After that, a passivation film 113 is deposited to manufacture a CMOS integrated circuit device.

On the other hand, FIG. 4 shows a conventional example of a semiconductor device in which two layers of aluminum wiring are used for extracting electrodes. In the figure, an element is formed on the main surface of the silicon substrate 101 as in the case of FIG. 3, but it is omitted for simplification of the figure. Then, the interlayer insulating film 1 is formed on the main surface of the silicon substrate 101.
07 is laminated, a first aluminum alloy film 112 which is a wiring metal film is formed thereon, and the second interlayer insulating film 1 is further formed.
14 is deposited, a via hole 9 is opened in this, and a titanium tungsten film 115 and a second aluminum alloy film 116 are sequentially deposited thereon by a known sputter deposition method.

[0006]

However, the above-mentioned conventional method of manufacturing a semiconductor device has the following problems.

First, in the case of using one layer of aluminum wiring, after the contact hole 8 is opened, the surfaces of the diffusion layers 106a and 106b and the polysilicon gate electrodes 105a and 105b formed on the silicon substrate are exposed. However, since these surfaces are water-repellent, if particles or the like adhere to the exposed surfaces in the steps of removing the photoresist and cleaning the surfaces, it is difficult to remove them and the particles tend to remain as they are until the final step. Furthermore, even during the sputtering process, particles and the like are likely to adhere. If the refractory metal or aluminum alloy film is vapor-deposited in the state where particles remain in the contact hole to form the electrode pattern, the long-term reliability of the semiconductor device and the processing yield are lowered.

Also in the semiconductor device using the two-layer aluminum wiring, the aluminum alloy film of the via hole 9 is easily oxidized in the intermediate step, and since these oxide films are generally thick, static electricity tends to accumulate and the oxide film-based Particles tend to adhere. Then, since dust in the liquid in the cleaning process is easily adsorbed in the via hole 9, when the surface of the first aluminum alloy film 112 is exposed in the via hole 9, eventually the particles in the via hole adhere to this surface. Will occur. Furthermore, in order to remove the thick alumina film formed on the surface of the first aluminum alloy film during the deposition of the second aluminum alloy film, rf etching using so-called reverse sputtering is performed as a pretreatment in the vacuum chamber. However, since the oxide film is etched by this rf etching, the metal oxide-based particles generated in this step are particularly liable to be charged with static electricity and easily serve as an adhesion source.

Therefore, the adhesion of particles resulting from these steps has been a major problem for improving the processing yield and long-term reliability of semiconductor devices.

The present invention has been made in view of the above circumstances, and an object thereof is to suppress the generation and adhesion of particles and the like accompanying the exposure of the surface of a silicon substrate, the surface of an aluminum alloy film or the like in the manufacturing process of a semiconductor device. By taking measures to prevent the connection failure in the contact hole or the via hole, it is possible to improve the processing yield and reliability of the metal wiring.

[0011]

In order to achieve the above object, the solution means of the present invention is to forcibly form an extremely thin oxide film on the exposed silicon or aluminum alloy surface in a contact hole or a via hole, and then A semiconductor device is manufactured by a method of diffusing and eliminating the oxide film by heat treatment.

Specifically, the means taken by the invention of claim 1 is, as shown in FIGS. 1 (a) to 1 (d), an element provided on a main surface of a semiconductor substrate as a method of manufacturing a semiconductor device. A step of forming a contact hole in the interlayer insulating film covering the element toward the signal connection part of the element, and dipping the surface exposed in the contact hole of the signal connection part of the element into an oxidizing solution for thin protection. Forming a protective oxide film, depositing a reducing metal film such as titanium on the protective oxide film, and depositing a wiring metal film such as an aluminum alloy on the reducing metal film And a step of forming an electrode pattern by etching a multi-layer metal film formed of each of the above metal films by a photo-etching method, and a step of heat-treating the multi-layer metal film to alloy it.

According to a second aspect of the present invention, the oxidizing solution according to the first aspect of the present invention is prepared by mixing the oxidizing solution with a mixed aqueous solution of hydrogen peroxide and ammonia water, a mixed aqueous solution of hydrogen peroxide and hydrochloric acid, sulfuric acid and hydrogen peroxide. Is a mixed aqueous solution or fuming nitric acid.

As shown in FIGS. 2A to 2C, the means taken by the invention of claim 3 is a method for manufacturing a semiconductor device, which is an element for covering an element provided on a main surface of a semiconductor substrate. It is premised on a semiconductor device including a coating interlayer insulating film, two or more metal wiring layers connected to the element, and a wiring coating interlayer insulating film coating the metal wiring layers.

Then, as a method of manufacturing a semiconductor device, a step of opening a via hole toward the metal wiring layer in a wiring coating interlayer insulating film which covers the metal wiring layer directly connected to the signal connection portion of the element. And a step of forming a thin protective oxide film by immersing the surface exposed in the via hole of the metal wiring layer in an oxidizing solution, and a reducing metal film such as titanium on the protective oxide film. The step of depositing,
A step of depositing a next metal film for wiring on the reducing metal film; a step of etching a multi-layer metal film composed of each metal film by a photo-etching method to form an electrode pattern; And a step of alloying the film by heat treatment.

According to a fourth aspect of the invention, the oxidizing solution in the third aspect of the invention is fuming nitric acid.

According to a fifth aspect of the invention, the wiring metal film according to the first or third invention is a multilayer film including a titanium tungsten film or a titanium nitride film and an aluminum alloy film. It is a thing.

[0018]

According to the first aspect of the invention, after the contact hole is opened, the surface of silicon or polysilicon forming the signal connection portion in the contact hole is covered with a thin protective oxide film. Therefore, since the intermediate step is advanced with these surfaces being hydrophilic, even if dust in the liquid adheres in the photo-etching step, it can be easily removed by washing, and various metal films can be removed by a treatment such as sputtering. Particles are unlikely to adhere to the openings even in the step of depositing, and as a result, the occurrence of defective connections in the contact holes is reduced. On the other hand, the thin protective oxide film is reduced by the reducing metal and disappears in the step of alloying the multilayer metal film by heat treatment, so that the contact resistance is kept good.

According to a second aspect of the present invention, in the above-mentioned first aspect, the oxidizing aqueous solution is a mixed aqueous solution of hydrogen peroxide and ammonia water, a mixed aqueous solution of hydrogen peroxide and hydrochloric acid, and a mixed aqueous solution of sulfuric acid and hydrogen peroxide. Alternatively, since fuming nitric acid is used, an extremely thin oxide film of about 1 nanometer is formed on the silicon or polysilicon surface of the signal connection portion of the device, and a particle adhesion suppressing action and a reducing action by reduction are obtained.

According to the third aspect of the present invention, the subsequent processing is performed with the surface of the metal wiring layer in the via hole being covered with a thin protective oxide film. Therefore, the thicker natural metal oxide film formed in the intermediate process is less likely to be electrostatically charged, and the need for rf etching suppresses the generation of oxide film-based particles that tend to adhere. Adhesion of particles and the like is reduced, the occurrence of defective connections is reduced, and the contact resistance is maintained excellently by the same action as that of the invention of claim 1.

In the invention of claim 4, in the invention of claim 3 above, fuming nitric acid is used as the oxidizing aqueous solution, and therefore, a pole of about 1 nanometer is formed on the surface of the aluminum alloy film constituting the surface layer of the metal wiring layer. A thin protective oxide film is formed, and an effect of suppressing particle adhesion and an effect of disappearing due to reduction are obtained.

According to a fifth aspect of the invention, the first or third aspect of the invention is provided.
In the invention, since the wiring metal film is a multilayer film including a titanium tungsten film or a titanium nitride film and an aluminum alloy film, the refractory metal film is interposed between the reducing metal film and the aluminum alloy film. Therefore, the contact resistance is reduced.

[0023]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

First, a first embodiment of a semiconductor device having a single layer of aluminum wiring will be described with reference to a partial structural sectional view of the CMOS integrated circuit device of FIG. FIG. 1A shows a state immediately after the contact hole is opened, and is a view corresponding to FIG. 3A in the above-mentioned conventional technique. That is, on the main surface of the P-type silicon substrate 101, the P-type well region 102a and the N-type well region 102 are formed.
b, an element isolation region 103 made of a silicon dioxide film is formed across the P-type well region 102a and the N-type well region 102b, and an N-type impurity is formed on the P-type well region 102a. A diffusion layer 106a is formed, and a P-type impurity diffusion layer 106b is formed on the N-type well region 102b.

Then, an interlayer insulating film 107 made of a silicon dioxide film for covering the surface of each of the above parts is provided, and the interlayer insulating film 107 has an impurity diffusion layer which is a signal connecting part formed on the silicon substrate. Contact holes 8 and 8 are opened toward 106a and 106b, respectively.

Reference numerals 104a and 104b denote gate oxide films for the N-channel portion and the P-channel portion, and 105, respectively.
Although a and 105b are gate electrodes made of polysilicon, respectively, and since these gate electrodes 105a and 105b are also signal connecting portions, contact holes are opened, but they are not shown in this figure.

Next, as shown in FIG. 1B, the impurity diffusion layers 106a, 106a exposed in the contact hole 8
A thin protective oxide film 1 is grown on the surface of 106b.
The protective oxide film 1 is formed by the photolithography method on the interlayer insulating film 1.
After opening a part of 07, it is immersed in an oxidizing solution such as a mixed aqueous solution of hydrogen peroxide and ammonia water, a mixed aqueous solution of hydrogen peroxide and hydrochloric acid, a mixed aqueous solution of sulfuric acid and hydrogen peroxide, or fuming nitric acid. Thus, the surface portion of silicon is oxidized to form a thin silicon dioxide film. then,
For example, in a mixed aqueous solution of hydrogen peroxide and ammonia water, the mixing ratio of hydrogen peroxide, ammonia water and water is 1: 1: 10.
In the case of (volume ratio), the protective oxide film 1 having a thickness of about 1 nanometer is formed on silicon at 70 ° C. for 20 minutes. The protective oxide film 1 may be formed by using another acidic aqueous solution, but in consideration of disappearing it later, the thickness is preferably about 2 nanometers.

Further, as shown in FIG. 1C, titanium, titanium-tungsten, and aluminum alloy are sequentially deposited by the sputter deposition method, and the titanium film 1 is sequentially deposited from the bottom.
After depositing 10, the titanium-tungsten film 111 and the aluminum alloy film 112, an electrode pattern is formed by a photolithography method.

Finally, as shown in FIG. 1D, after heating each metal atom to 450 ° C. in a hydrogen atmosphere to interdiffuse each metal atom and alloy each metal film 110, 111, 112. , A passivation film 1 made of a silicon nitride film
Deposit 13. At that time, the thin protective oxide film 1 in FIG. 1B is reduced by titanium and disappears when heat treatment is performed in hydrogen at 450 ° C. That is,
By interposing the titanium film 110 between the protective oxide film 1 and the titanium-tungsten film 111, the thin protective oxide film 1 on the silicon surface is reduced to silicon and disappears. That is, up to this heat treatment step, an intermediate step can be performed with the silicon surface in the contact hole 8 being covered with the protective oxide film 1. If the thickness of the titanium film 110 is 30 nanometers or more, it is sufficient to reduce and eliminate the protective oxide film 1.

As described above, in the first embodiment, after the contact hole 8 was opened, the thin protective oxide film 1 was grown on the silicon surface exposed in the contact hole 8 for the purpose of cleaning the surface, and thereafter, Since the titanium film 110 is piled up and the titanium film 110 is interposed between the protective oxide film 1 and the titanium tungsten film 111, the silicon surface in the contact hole 8 is covered with the protective oxide film 1. It is possible to proceed with the steps in the hydrophilic state. Therefore, in the photo-etching process, even if dust in the liquid adheres, it can be easily removed by washing, and the reducing metal film such as the titanium film 110, the titanium-tungsten film 111, and the aluminum alloy film can be processed by a process such as sputtering. Even in the step of depositing 112 and the like, particles are unlikely to adhere to the openings, and finally the number of particles remaining in the contact holes 8 is reduced. As a result, the occurrence of defective connections in the contact hole 8 is reduced.

On the other hand, the protective oxide film 1 is a titanium film 11
0, in the alloying process of the titanium-tungsten film 111 and the aluminum alloy film 112, the resistance of titanium that has been reduced by titanium and disappeared and absorbed oxygen has a small change in the measurement of the electrical resistance value, and the contact resistance value is small. Is no different from the conventional structure. The contact resistance value with polycrystalline silicon is also the same. Further, it is unknown whether a part of oxidized titanium evaporates or remains in a state of absorbing oxygen, but there is no problem at all from the resistance value and the long-term reliability evaluation of the device.

In the first embodiment, the titanium-tungsten film is used, but the same effect can be obtained by using the titanium-nitride film.

Next, a second embodiment of the present invention will be described. FIG. 2 shows a CMOS having two layers of aluminum wiring.
The manufacturing process of the integrated circuit device is shown, and like FIG. 4 in the above-mentioned conventional example, the element portion is omitted and only the two-layer aluminum wiring portion is shown for simplification.

First, as shown in FIG. 2A, the P-type silicon substrate 101 is covered with the first interlayer insulating film 107 as in FIG. 4 in the above-mentioned conventional example, and the first interlayer insulating film 107 is formed. The first aluminum alloy film 1 is formed on the insulating film 107.
12 and a second interlayer insulating film 114 are formed, and the via hole 9 is formed in the second interlayer insulating film 114.
Is opened, and the connection port with the first aluminum alloy film 112 is exposed.

Next, as shown in FIG. 2B, the surface of the first aluminum alloy film 112 is dipped in fuming nitric acid to oxidize the surface, and at the same time, the organic components adhering to the surface are removed. .. By this treatment, a thin protective oxide film 2 is formed on the surface of the first aluminum alloy film 112. Then, the titanium film 11 is formed by the sputter deposition method.
5. After continuously depositing the titanium-tungsten film 116 and the aluminum alloy film 117, the electrode wiring pattern is formed by a well-known photo-etching method. When this is alloyed at 450 ° C. as in Example 1, the thin protective oxide film 2 on the first aluminum alloy film 112 is reduced and disappears.

Therefore, in the second embodiment, the first aluminum alloy film 1 which is the electric wiring layer in the via hole 9 is formed.
The intermediate process is performed with the surface of 12 covered with the thin protective oxide film 2. This protective oxide film 2 is less likely to generate static electricity and is less likely to cause adhesion of particles during processing, as compared with a natural thick alumina oxide film which is generated in the intermediate step when there is no oxide film. Further, since rf etching for removing the natural alumina oxide film is not necessary, there is almost no generation of alumina which is easily charged with static electricity. Therefore, the amount of particles attached can be reduced, and the occurrence of defective connection can be suppressed. Further, in the step of alloying at 450 ° C., the protective oxide film 2 on the first aluminum alloy layer 112 is reduced and disappears, and the contact resistance value is maintained good as in the first embodiment.

Similar to the first embodiment, even if titanium nitride is used as the refractory metal film, the same effect as the titanium tungsten film can be obtained.

Further, the surface can be oxidized by various oxidizing solutions. Particularly, in the step where no metal is used in the holes, a mixed aqueous solution of hydrogen peroxide and ammonia water, a mixed aqueous solution of hydrogen peroxide and hydrochloric acid. A mixed aqueous solution of sulfuric acid and hydrogen peroxide is preferable, and in a process using a metal film such as an aluminum alloy, it is possible to oxidize with fuming nitric acid.

Further, in each of the above-described embodiments, as the wiring metal film, the titanium-tungsten film 111 (or 116) which is a refractory metal film is deposited on the titanium film 110 (or 115), and the aluminum film is stacked thereon. Although the alloy film 112 (or 117) is deposited, the aluminum alloy film 112 (or 117) may be directly deposited on the titanium film 110 (or 115) without the refractory metal film. However, by interposing the refractory metal film 111 (or 116) in the middle, it is possible to reduce the contact resistance as described above, and thus it is possible to exert a remarkable effect.

Further, in each of the above embodiments, a metal having a reducing power other than titanium can be applied to the material forming the reducing metal film.

[0041]

According to the invention of claim 1, as a method of manufacturing a semiconductor device, a contact hole is formed in an interlayer insulating film toward a connecting portion of an element, and the surface of the connecting portion of the element exposed in the contact hole. Is immersed in an oxidizing solution to form a thin protective oxide film to make the surface hydrophilic, and then a reducing metal film such as titanium and a metal film for wiring are continuously deposited. As a result, the thin protective oxide film is eliminated so that the adhesion of particles in the contact holes can be suppressed and the contact resistance characteristics can be maintained well. It is possible to increase the density of the integrated circuit while preventing the increase of

According to the invention of claim 2, in the invention of claim 1, the oxidizing solution is a mixed aqueous solution of hydrogen peroxide and ammonia water, a mixed aqueous solution of hydrogen peroxide and hydrochloric acid,
Since a mixed aqueous solution of sulfuric acid and hydrogen peroxide or fuming nitric acid is used, a very thin protective oxide film can be formed on the surface of the connection part of the element, improving the effect of suppressing particle adhesion and reducing or eliminating the protective oxide film. It is possible to improve the contact resistance.

According to the third aspect of the invention, as a method of manufacturing a semiconductor device, an interlayer insulating film for element covering, two or more metal wiring layers, and an interlayer insulating film for wiring covering each metal wiring layer are provided. As a method of manufacturing a semiconductor device comprising: a wiring coating interlayer insulating film that covers a metal wiring layer directly connected to a signal connection portion of an element, a via hole is opened toward the metal wiring layer, and The surface of the exposed metal wiring layer is immersed in an oxidizing solution to form a thin protective oxide film, and then a reducing metal film such as titanium and the next wiring metal film are successively deposited to form an electrode. Since the alloy is formed by heat treatment after pattern formation, it is possible to proceed with the process in the state of being protected by a thin protective oxide film instead of the thick natural oxide film generated in the intermediate process, and thus, having a multi-layer metal wiring layer. About semiconductor devices It is possible to obtain the same effect as the invention of the claim 1.

According to the invention of claim 4, in the invention of claim 3, since the fuming nitric acid is used as the oxidizing solution, it is possible to form a very thin protective oxide film on the surface of the metal wiring layer and to attach particles. It is possible to improve the suppressing effect and improve the contact resistance due to reduction and disappearance of the protective oxide film.

According to the invention of claim 5, in the invention of claim 1 or 3, the wiring metal film is a multilayer film of a titanium tungsten film or a titanium nitride film and an aluminum alloy film. Can be favorably maintained, and therefore, the remarkable effects of the above-mentioned inventions can be exhibited.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram illustrating a method of manufacturing a semiconductor device according to a first embodiment.

FIG. 2 is a manufacturing process diagram illustrating a method of manufacturing a semiconductor device according to a second embodiment.

FIG. 3 is a manufacturing process diagram showing a conventional method for manufacturing a semiconductor device having a single-layer aluminum wiring.

FIG. 4 is a manufacturing process diagram of a conventional method for manufacturing a semiconductor device having a two-layer aluminum wiring.

[Explanation of symbols]

1, 2 Oxide film for protection 8 Contact hole 9 Via hole 101 Silicon substrate 105a, 105b Gate electrode (signal connection part) 106a N-type impurity diffusion layer (signal connection part) 106b P-type impurity diffusion layer (signal connection part) 107 Interlayer Insulating film 110,115 Titanium film (reducing metal film) 111,116 Titanium tungsten film (refractory metal film) 112,117 Aluminum alloy film 114 Second interlayer insulating film (interlayer insulating film for wiring coating)

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location H01L 21/90 B 7353-4M // H01L 21/283 L 7738-4M

Claims (5)

[Claims] 1. A step of forming a contact hole in an interlayer insulating film, which covers an element provided on a main surface of a semiconductor substrate, toward a signal connection portion of the element, and inside the contact hole of the signal connection portion of the element. Forming a thin protective oxide film by immersing the exposed surface in an oxidizing solution, depositing a reducing metal film such as titanium on the protective oxide film, and the reducing metal film. A step of depositing a metal film for electrical wiring such as an aluminum alloy, and a step of etching a multi-layer metal film composed of each of the metal films by a photo-etching method to form an electrode pattern, and the multi-layer metal film. A method of manufacturing a semiconductor device, comprising: 2. The method of manufacturing a semiconductor device according to claim 1, wherein the oxidizing solution is a mixed aqueous solution of hydrogen peroxide and ammonia water, a mixed aqueous solution of hydrogen peroxide and hydrochloric acid, a mixed aqueous solution of sulfuric acid and hydrogen peroxide, or A method for manufacturing a semiconductor device, which is fuming nitric acid. 3. An element-covering interlayer insulating film for covering an element, which is provided on a main surface of a semiconductor substrate, two or more metal wiring layers connected to the element, and wiring for covering each of the metal wiring layers. A method for manufacturing a semiconductor device comprising a coating interlayer insulating film, comprising: a wiring coating interlayer insulating film for coating a metal wiring layer directly connected to a signal connection portion of the element, facing the metal wiring layer. A step of forming a via hole; a step of forming a thin protective oxide film by immersing the surface of the metal wiring layer exposed in the via hole in an oxidizing solution; and titanium or the like on the protective oxide film. The step of depositing the reducing metal film, and the step of depositing the next wiring metal film on the reducing metal film, and the multi-layer metal film consisting of the above metal films is etched by a photo-etching method. Forming an electrode pattern by using The method of manufacturing a semiconductor device characterized by comprising a step of alloying by heat-treating. 4. The method of manufacturing a semiconductor device according to claim 3, wherein the oxidizing solution is fuming nitric acid. 5. The semiconductor manufacturing method according to claim 1, wherein the wiring metal film is a multilayer film including a titanium tungsten film or a titanium nitride film and an aluminum alloy film. Device manufacturing method.