JPH09283490A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor device, wherein wet etching velocity to a metallic layer in which silicon is mixed to aluminum is extremely rapid and an element can be prepared in a short period of time. SOLUTION: A semiconductor device is manufactured by a method including a process for forming a metallic layer on at least one main surface of a semiconductor board, a process for forming a mask layer exposing a selected region on a metallic layer, a process for removing a selected region of a metallic layer by a mask layer by wet etching (at least etchant containing phosphoric acid) method and a process for removing a mask layer. In the method, a metallic layer is a metallic layer [Al-Si (0.5 to 1.5%)] wherein silicon is mixed to aluminum which is formed by sputtering deposition, and the method includes a process for carrying out at least one heat treatment at a temperature exceeding 200 deg.C while a metallic layer is formed or after it is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device which has a high wet etching rate of a metal layer formed on a semiconductor substrate and can reduce the time required for manufacturing an element. .

[0002]

In the conventional method for manufacturing a semiconductor device, for example, when a metal layer in which aluminum is mixed with silicon is formed on a semiconductor substrate, the silicon concentration is the mechanical characteristics of the metal layer. And the electrical properties are adjusted to obtain the desired values. The concentration of this silicon is preferably in the range of 0 to 2% by weight,
In the usual case, the range of 0.5% to 1.5% is the most preferable. The metal layer in which silicon is mixed with aluminum is formed by, for example, the sputter vapor deposition method, but the formation temperature of the metal layer by the sputter vapor deposition method is usually
It is in the range of 0 ° C to 200 ° C. Then, a mask layer made of photoresist is formed in a predetermined pattern on the metal layer, and at least a portion to be etched is selectively removed by a wet etching method using phosphoric acid. In this case, an etching solution is preferable. The temperature is selected from the range of 40 ° C. to 60 ° C., which has the highest etching rate under the condition that the mask layer made of photoresist is not removed by etching, and the range of 45 ° C. to 55 ° C. is particularly preferable. Next, the mask layer is removed using oxygen plasma or the like, and a pattern of a metal layer in which aluminum is mixed with silicon is formed on the semiconductor substrate. In the method of manufacturing a semiconductor device according to the above-mentioned conventional technique, there is a problem that the wet etching rate by phosphoric acid of a metal layer in which silicon is mixed with aluminum formed by a Svatta vapor deposition method is low, and it takes a lot of time to manufacture the semiconductor device. It was

An object of the present invention is to solve the above-mentioned problems of the prior art, that is, a semiconductor device capable of producing an element in a short time because the wet etching rate for a metal layer in which aluminum is mixed with silicon is extremely high. It is to provide a manufacturing method of.

[0004]

In order to achieve the above-mentioned object of the present invention, the present invention has a constitution as set forth in the claims. That is, according to the present invention, as described in claim 1, a step of forming a metal layer on at least one main surface of a semiconductor substrate, and a step of forming a mask layer exposing a selected region on the metal layer. A method for manufacturing a semiconductor device, comprising: a step of removing the metal layer by wet etching in a region selected by the mask layer; and a step of removing the mask layer, wherein the metal layer is formed by sputtering vapor deposition. Which is a metal layer formed by mixing silicon into aluminum formed by the method, and during or after film formation of the metal layer, heat treatment is performed at a temperature of more than 200 ° C. at least once, and the wet etching is performed at least. A method of manufacturing a semiconductor device using an etching solution containing phosphoric acid. Further, according to the present invention, as described in claim 2, in the metal layer formed by the sputtering deposition method according to claim 1, in which the aluminum is mixed with silicon, the content of silicon is 0.5% to 1% by weight. The manufacturing method of the semiconductor device is within the range of 0.5%. In the method for manufacturing a semiconductor device of the present invention, by performing a heat treatment at a temperature of more than 200 ° C. at least once during or after vapor deposition, a metal layer formed by mixing silicon with aluminum formed by a sputtering vapor deposition method, The present invention has been made to find that the metal layer has a wet etching rate of at least 4 to 5 times faster than that of the conventional case using phosphoric acid, and thus the manufacturing time of a semiconductor element can be significantly shortened. effective.

[0005]

According to the present invention, as described in claim 1, a metal layer in which silicon is mixed with aluminum formed by the sputtering vapor deposition method is used during or after the formation of the metal layer. By using the step of performing heat treatment at a temperature higher than ° C, the metal layer has an etching rate which is 4 to 5 times higher than that of the conventional method in wet etching using phosphoric acid, and the manufacturing time of a semiconductor element can be significantly shortened. effective. Further, according to the present invention, as described in claim 2, the silicon concentration (% by weight) in the metal layer obtained by mixing silicon with aluminum formed by the sputtering deposition method is in the range of 0.5% to 1.5%. By doing so, it is possible to obtain a metal layer having good mechanical properties and electrical properties, and it is possible to perform patterning at an etching rate 4 to 5 times higher than that of the conventional technique, and to obtain a semiconductor element having excellent performance in a short time. There is an effect that can be produced in.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> The present embodiment will be described with reference to FIGS. 1 and 2. 1 is a process diagram showing the manufacturing process of the semiconductor device of the present invention, and FIG. 2 shows the relationship between the wet etching rate and the sputter deposition temperature. In FIG. 1, a metal layer 2 in which aluminum is mixed with silicon is formed on a semiconductor substrate 1. The concentration of silicon (% by weight) in the metal layer 2 is selected so that the mechanical and electrical characteristics of the metal layer 2 in which aluminum is mixed with silicon have desired values. This preferred concentration is, for example, that the concentration of silicon relative to aluminum is in the range of 0% to 2%, usually 0.5% to 1.5%.
The range of% is the most preferable. Then, the metal layer 2 in which this aluminum is mixed with silicon is formed by a sputtering evaporation method. The temperature of the metal layer 2 at the time of film formation by this sputtering deposition was set to a temperature exceeding 200 ° C. Next, the mask layer 3 made of photoresist is formed into a predetermined pattern [FIG. 1 (a)]. Next, the etched portion 4 is selectively removed by a wet etching method using at least phosphoric acid [FIG. 1 (b)]. FIG. 2 shows that by the scutter vapor deposition method, during vapor deposition, 50 ° C., 100 ° C., and 150 ° C., respectively.
0.5% silicon on aluminum deposited at a deposition temperature (° C) of 200 ° C, 200 ° C, 250 ° C or 300 ° C.
% -1.5% mixed metal layer, phosphoric acid (temperature 50
Shows the wet etching rate [nm (nanometer) / min] when etching is performed using (° C.). The vapor deposition temperature in the prior art is a temperature of 50 ° C., 100 ° C., 150 ° C. or 200 ° C. or less, and 5 for a metal layer in which silicon is mixed with aluminum formed at this vapor deposition temperature.
The etching rate with phosphoric acid at 0 ° C. is about 200 nm per minute as shown in FIG. On the other hand, phosphoric acid (temperature: 50 ° C.) for a metal layer formed by a sputtering vapor deposition method at a vapor deposition temperature exceeding 200 ° C., that is, 250 ° C. or 300 ° C.
As shown in FIG. 2, the wet etching rate by
The metal layer of the present invention, which has an etching rate of about 900 nm per minute and is deposited at a deposition temperature of more than 200 ° C., has a wet etching rate of about 4 to 5 times higher than that of the prior art. It is possible to significantly reduce the manufacturing time. Next, the mask layer 3 is removed using oxygen plasma or the like. By the manufacturing process as described above, the pattern 5 of the metal layer in which silicon is mixed with aluminum can be formed on the semiconductor substrate 1 at an etching rate about 4 to 5 times higher than that of the conventional technique [FIG.
(C)], the manufacturing time of the semiconductor element can be significantly shortened.

<Second Embodiment> The present embodiment will be described with reference to FIGS. 3 and 4. Note that FIG.
FIG. 4 is a process diagram showing the manufacturing process of the semiconductor device of the present invention, and FIG. 4 shows the relationship between the wet etching rate and the heating temperature after sputtering deposition. A metal layer 7 in which aluminum is mixed with silicon is formed on the semiconductor substrate 6. The silicon concentration (wt%) of the metal layer 7 is selected so that the mechanical and electrical characteristics of the metal layer 7 in which aluminum is mixed with silicon have desired values. This silicon concentration is 0%
To 2%, usually 0.5% to 1.
The range of 5% is the most preferable. A metal layer 7 in which silicon is mixed with aluminum is formed by a scatter vapor deposition method. In addition, the film formation temperature of this sutter vapor deposition is from 0 ° C to 20 ° C.
It is in the range of 0 ° C [Fig. 3 (a)]. Next, the metal layer 7 in which aluminum is mixed with silicon is heated to a temperature exceeding 200 ° C. The heating time at a temperature above 200 ° C. is preferably 10 minutes or longer. FIG. 3B shows the metal layer 8 in which aluminum is mixed with silicon after being heated to a temperature exceeding 200 ° C. Then, a predetermined pattern is formed on the mask layer 9 made of photoresist. [Fig.
(B)]. Next, the etched portion 10 is selectively removed by a wet etching method using phosphoric acid [FIG. 3 (c)]. FIG. 4 shows a metal layer obtained by mixing 0.5 to 1.5% by weight of aluminum with aluminum by a scutter vapor deposition method, for example, by scutter vapor deposition in a temperature range of 90 ° C. to 110 ° C. which is a conventional technique. , 50 ℃,
100 ° C, 150 ° C, 200 ° C, 250 ° C or 300
The wet etching rate by phosphoric acid (temperature 50 ° C.) for the metal layer heat-treated for about 10 minutes at a temperature of ° C. is shown. 50 layers of metal mixed with silicon in aluminum
The metal layer heat-treated at each temperature of 100 ° C., 100 ° C., 150 ° C. or 200 ° C. for about 10 minutes has a wet etching rate of about 200 nm per minute as shown in FIG. The metal layer heated to 250 ° C. or 300 ° C. which is higher than 200 ° C. for about 10 minutes has a wet etching rate of about 900 nm per minute, which is about 4 to 5 times higher than that of the prior art. . Therefore, the manufacturing time of the semiconductor element can be significantly shortened. here,
FIG. 5 shows the etchant (phosphoric acid) temperature dependence of the Al-Si (1.0%) sputtered film etching rate (nm / min). The etching pressure is 40 (mBa
r), and ○ in the figure indicates the case of after-annealing at 300 ° C. for 20 minutes, and □ indicates the case of no after-annealing. As is clear from the figure, the higher the phosphoric acid temperature, the faster the etching rate, and the one after-annealed shows an etching rate about 4 to 5 times higher than that without post-annealing. Next, the mask layer 9 is removed by oxygen plasma or the like. By the above manufacturing method, the pattern 11 of the metal layer in which silicon is mixed with aluminum can be formed on the semiconductor substrate 6 at an etching rate which is 4 to 5 times faster than that of the conventional technique [FIG. )].

<Third Embodiment> In the second embodiment, the metal layer 8 shown in FIG. 4 (b), which is a mixture of aluminum and silicon after being heated to a temperature exceeding 200 ° C. When forming, a direct heating device such as a hot plate is used to heat to a temperature exceeding 200 ° C.

<Fourth Embodiment> In the second embodiment, the metal layer 8 shown in FIG. 4B, which is a mixture of aluminum and silicon after being heated to a temperature exceeding 200 ° C. In the case of forming, the material is heated to a temperature exceeding 200 ° C. by an indirect heating device such as an oven.

<Fifth Embodiment> In the second embodiment, a metal layer 8 shown in FIG. 4 (b), which is a mixture of aluminum and silicon after being heated to a temperature exceeding 200 ° C. 200 ° C by applying high frequency when forming
Heat to a temperature above.

[Brief description of drawings]

FIG. 1 is a process diagram showing a manufacturing process of a semiconductor device of the present invention, which is exemplified in the first embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the sputter deposition temperature and the wet etching rate exemplified in the first embodiment of the present invention.

FIG. 3 is a process drawing showing a manufacturing process of the semiconductor device of the present invention exemplified in the second embodiment of the present invention.

FIG. 4 is a graph showing the relationship between the heating temperature after the sputter deposition and the wet etching rate as exemplified in the second embodiment of the present invention.

FIG. 5 is an Al-S exemplified in the second embodiment of the invention.
The graph which shows the temperature dependence of i (1.0%) sputtered film etching rate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor substrate 2 ... Metal layer in which aluminum is mixed with silicon 3 ... Mask layer 4 ... Etched portion 5 ... Pattern of metal layer in which aluminum is mixed with silicon 6 ... Semiconductor substrate 7 ... Metal layer in which aluminum is mixed with silicon 8 ... Metal layer in which silicon is mixed with aluminum after being heated to a temperature exceeding 200 ° C. 9 ... Mask layer 10 ... Etched portion 11 ... Pattern of metal layer in which silicon is mixed with aluminum

Claims (2)

[Claims] 1. A step of forming a metal layer on at least one main surface of a semiconductor substrate, a step of forming a mask layer exposing a selected region on the metal layer, the metal layer being the mask layer. A method of manufacturing a semiconductor device, which comprises at least a step of removing a region selected by wet etching by wet etching, and a step of removing the mask layer, wherein the metal layer includes silicon formed on aluminum formed by a spat evaporation method. A mixed metal layer, which is subjected to heat treatment at a temperature of more than 200 ° C. at least once during or after the formation of the metal layer, and the wet etching uses an etching solution containing at least phosphoric acid. A method for manufacturing a semiconductor device, comprising: 2. The metal layer in which silicon is mixed with aluminum formed by the sputtering vapor deposition method according to claim 1,
A method of manufacturing a semiconductor device, wherein the content of silicon is in the range of 0.5% to 1.5% by weight.