JPH1187262A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To process a titanium-tungsten film having a selectivity to an aluminum film by a low-cost wet method defining a chemical by a method, wherein a semiconductor device is provided with the titanium-tungsten film formed on a semiconductor substrate and an insulating film and the aluminum film laminated on this titanium-tungsten film. SOLUTION: A P-N junction 2 and an oxide film 3 are formed in an Si substrate 1 and on the Si substrate 1, and thereafter the film 3 is made to be opened by a photolithographic method to form a contact hole. Moreover, after a photoresist has been peeled off, a choline base treatment and a dilute hydrofluoric acid treatment are performed, then a TiW film 4 of a prescribed film thickness and an Al film 5 are formed through sputtering. These films are films subjected to metal work. Thereafter, subsequently, the Al film 5 is etched with the mixed solution consisting of ammonia, hydrogen peroxide, water and the like using a photoresist 6, which is used as a mask pattern, as a mask. Moreover, after the film 4 under the Al film 5 has been etched, the photoresist is peeled off and an electrode is formed on the rear of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device produced by using a tungsten mixed film containing 5 to 15% of titanium, which is used as an electrode, for example, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, when tungsten or titanium tungsten is processed by wet etching, a hydrogen peroxide solution or a mixed solution of a hydrogen peroxide solution and an ammonia solution has been used. In such wet etching, there is an advantage that, unlike dry etching, there is no adhesion of titanium in an etching chamber or the like and generation of particles is suppressed. In view of such a point, it is widely used in a transistor forming process and the like.

[0003] For example, in Japanese Patent Application Laid-Open No. 8-53881, ED is used as an etchant for a titanium tungsten alloy thin film.
30% of 40-60 ° C with addition of TA and potassium sulfate
A technique of chemically etching using a hydrogen peroxide solution is disclosed.

Further, in Japanese Patent Application Laid-Open No. 8-250462, when patterning a titanium tungsten film in a contact hole, wet etching with a hydrogen peroxide solution or a mixed solution is performed, followed by dry etching with a hydrofluoric acid-based gas.
There has been disclosed a technique for removing a conductive residue at the time of etching and reducing leakage between wirings.

Japanese Patent Application Laid-Open No. Hei 2-100376 discloses a technique in which titanium tungsten is used as a contact metal and is etched and removed by a resist mask and an aqueous hydrogen peroxide solution to perform patterning.

On the other hand, on a silicon substrate, titanium
500-5000 tungsten mixture film containing 15%
[Angstrom] and a metal process of a semiconductor device having a two-layered electrode in which aluminum is laminated in a thickness of 1 to 5 μm, the processing method is to process thick aluminum by a wet method and then further process titanium tungsten. Performing step etching has been performed.

[0007]

However, in the above-described method of processing titanium tungsten, a wet method is used, and the cost for performing single-wafer processing using reactive ion etching (RIE) in a dry method is increased. However, in the wet method capable of batch processing, there has been a conventional problem that the selection of a chemical solution has not been determined.

The present invention has been made in view of the above-mentioned problems, and has as its object to provide a semiconductor device capable of processing titanium tungsten having selectivity with Al by an inexpensive wet method in which a chemical solution is determined. The manufacturing method can be provided.

[0009]

To achieve the above object, a semiconductor device according to a first aspect of the present invention comprises a semiconductor substrate, a PN junction formed on the semiconductor substrate, and a semiconductor device having a PN junction formed on the surface of the semiconductor substrate. An insulating film stacked and partially removed, titanium tungsten formed on the semiconductor substrate and the insulating film, and aluminum stacked on the titanium tungsten; It is characterized in that a two-layer metal of tungsten and aluminum is selectively formed, the aluminum is etched, and processing is performed using a heated hydrogen peroxide solution as a processing liquid for the titanium tungsten.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device having a PN junction on a semiconductor substrate, wherein an insulating film is formed on a surface of the semiconductor substrate and the insulating film is partially removed. A second step of forming a film of titanium tungsten on the entire semiconductor substrate, a third step of stacking aluminum on the titanium tungsten by 1 to 5 μm, and a two-layer metal of titanium tungsten and aluminum. And a fifth step of etching the aluminum, wherein the processing is performed by using a heated hydrogen peroxide solution as a processing solution for titanium tungsten. I do.

That is, in the semiconductor device according to the first aspect of the present invention, a PN junction is formed on the semiconductor substrate, an insulating film is formed on the surface of the semiconductor substrate, and a part thereof is partially removed. Titanium tungsten is formed on a semiconductor substrate and an insulating film, aluminum is stacked on the titanium tungsten, and a two-layer metal formed by the titanium tungsten and aluminum is selectively patterned, and the aluminum is etched. Titanium tungsten is processed using a heated hydrogen peroxide solution as a processing chemical.

In a method of manufacturing a semiconductor device according to a second aspect, in a semiconductor device having a PN junction on a semiconductor substrate, an insulating film is formed on a surface of the semiconductor substrate in a first step, and the insulating film is partially formed. In a second step, a film of titanium tungsten is formed on the entirety of the semiconductor substrate, in a third step, aluminum is stacked on the titanium tungsten in a thickness of 1 to 5 μm, and in a fourth step, the titanium tungsten and aluminum are deposited. In the fifth step, the aluminum is etched, and processing is performed using a heated hydrogen peroxide solution as a processing liquid for titanium tungsten in particular.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. The present invention provides a mixture film of tungsten (hereinafter, referred to as W) containing 5 to 15% of titanium (hereinafter, referred to as Ti) used as an electrode.
It has a feature in the processing step of TiW), and as a chemical solution for etching the TiW, for example, a 30 to 35 wt% aqueous hydrogen peroxide solution heated to 35 to 80 ° C is used.

FIG. 1 shows a manufacturing process of a semiconductor device according to an embodiment of the present invention in which electrodes are formed by a characteristic processing method. In the semiconductor device of the present invention, first, after a PN junction 2 and an oxide film 3 are formed on a silicon (hereinafter referred to as Si) substrate 1 (see FIG. 1A), the oxide film 3 is opened by photolithography. Form a contact hole. Then, after the photoresist is removed, a choline-based treatment and a treatment with diluted hydrofluoric acid (HF) for the purpose of removing contamination and a natural oxide film are performed (see FIG. 1B).

Next, a 2000 [Angstrom] TiW film 4 is sputtered, and then 3.8 μm Al5 is sputtered. At this time, the target composition of the TiW film 4 is as follows.
A material containing 10% of Ti and 90% of W is used. Subsequently, since these are metal processing, Al5 is changed to ammonia, using photoresist 6 as a mask pattern as a mask.
Etching is performed with a mixed solution of hydrogen peroxide, a chelating agent and water.

Further, the underlying TiW film 4 is etched using this method. That is, a 35 wt% aqueous hydrogen peroxide solution is controlled at 40, 60, 75 +/− 5 ° C. with a chemical solution of 10%.
Then, the TiW film 4 is etched by soaking for a minute to separate the gate and the emitter. The size of the blank on the mask at this time is 5 μm.
Of width. After that, the photoresist is removed, and an electrode is formed on the back surface (see FIGS. 1C and 1D). The configuration of the semiconductor device according to the present embodiment manufactured as described above is as shown in FIG.

Here, FIG. 2 shows and illustrates a processed shape of an end portion by a dry method or a wet method. When the electrical characteristics and breakdown voltage characteristics of the sample shown in FIG.
The characteristics of the wet processing using the hydrogen peroxide solution shown in FIG. 2B are lower than those of the RIE processed sample by the dry method shown in FIG. No -E short (caused by the residue on the contact portion between Si and metal) is not observed. The yield was 67 to 78, 70 for both dry and wet methods.
There is no difference in%. That is, it is clear that there is no reduction in yield due to the processing method.

Next, FIG. 3 is a view showing the relationship between the etching temperature of the chemical solution, the etching rate, and the amount of side etching. Note that, in the drawing, the white dots indicate the characteristics related to the relationship between the etching temperature and the etching rate,
The characteristics indicated by the crosses indicate the relationship between the etching temperature and the side etching amount.

It can be seen that when the temperature is low, the etching rate becomes very low, and it is necessary to use at a temperature of 35 ° C. or higher.
Such an etching rate is 500 angstroms /
Min (40 ° C.), but an etching time of about 10 minutes is necessary for removing the residual with, for example, a 2000-Å-thick TiW film.

On the other hand, the progress of side etching due to excessive etching time generates dust due to curling and peeling of the Al bottom, which causes a short circuit. In order to suppress this, the etching temperature needs to be 80 ° C. or lower. The processing results at this time are as follows: line width 4 μm in mask dimensions
That is all.

As described above, in the present invention, by using aqueous hydrogen peroxide in the electrode processing step, the base resin, photosensitive agent, solvent (E) used for patterning are used.
There is no problem of deterioration of the resist containing CA) as a main component and significant retreat of Al. Then, processing by an inexpensive wet method is realized.

[0022]

As described in detail above, according to the present invention,
It is possible to provide a semiconductor device capable of processing titanium tungsten having selectivity with Al by an inexpensive wet method in which a chemical solution is determined, and a method of manufacturing the same.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure process of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a structure of a semiconductor device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a structure of a processed end portion of a dry method and a wet method according to an embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between an etching temperature, an etching rate, and a side etching amount according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 silicon substrate 2 PN junction 3 oxide film 4 titanium tungsten 5 aluminum 6 resist

Claims (10)

[Claims] A semiconductor substrate; a PN junction formed on the semiconductor substrate; an insulating film laminated on a surface of the semiconductor substrate, a part of which is partially removed; and the semiconductor substrate and the insulating film. A titanium tungsten film formed thereon, and aluminum laminated on the titanium tungsten, selectively patterning two layers of the titanium tungsten and the aluminum, etching the aluminum, and etching the titanium tungsten A semiconductor device characterized by processing using a heated hydrogen peroxide solution as a processing chemical liquid. 2. The semiconductor device according to claim 1, wherein the titanium-tungsten film composition contains 5 to 15% of titanium, and the film thickness is 500 to 5,000 angstroms. 3. The semiconductor device according to claim 1, wherein the processing is performed using a hydrogen peroxide solution of the chemical at an operating temperature of 35 to 80 ° C. and a chemical concentration of 30 to 35 wt%. 4. The processed shape is characterized in that aluminum has a trapezoidal shape and a hypotenuse is rounded, and titanium tungsten thereunder satisfies a range of a side etching amount of 2 μm from under the trapezoidal bottom. The semiconductor device according to claim 1. 5. The semiconductor device according to claim 1, wherein the width of the titanium tungsten blank pattern is 4 μm or more. 6. A semiconductor device having a PN junction on a semiconductor substrate, comprising: a first step of forming an insulating film on a surface of the semiconductor substrate and partially removing the insulating film; A second step of forming a titanium tungsten film, and aluminum of 1 to 5 μm on the titanium tungsten.
A third step of laminating; a fourth step of selectively patterning a two-layer metal of titanium tungsten and aluminum; and a fifth step of etching the aluminum. A method for manufacturing a semiconductor device, wherein processing is performed using a heated hydrogen peroxide solution as a chemical solution. 7. The method of manufacturing a semiconductor device according to claim 6, wherein said titanium tungsten film composition contains 5 to 15% of titanium and has a thickness of 500 to 5000 Å. 8. The method for manufacturing a semiconductor device according to claim 6, wherein the hydrogen peroxide solution of the chemical solution is processed using an operating temperature of 35 to 80 ° C. and a chemical concentration of 30 to 35 wt%. . 9. The shape after the processing is such that aluminum has a trapezoidal shape and a hypotenuse is rounded, and titanium tungsten thereunder has a side etching amount of 2 from the bottom of the trapezoidal shape.
The method according to claim 6, wherein a range of μm is satisfied. 10. The method of manufacturing a semiconductor device according to claim 6, wherein the width of the titanium tungsten punched pattern is 4 μm or more.