JPH07297198A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain an aluminum wiring layer in a correct size by a method wherein a resist pattern containing a light absorbent is used as a mask, an oxide film under it is etched and removed, the resist film pattern and the oxide film which has been patterned are used as a mask and an aluminum layer under it is etched and removed. CONSTITUTION:An oxide film 12 is formed on an aluminum layer 11, a resist film 13 containing a light absorbent is formed on the oxide film 12, a desired region in the resist film 13 containing the light absorbent is exposed and developed, and a resist pattern 13A is formed. Then, by making use of the resist pattern 13A as a mask, the oxide film 12 is etched and removed so as to be patterned. In addition, by making use of the resist pattern 13A and the patterned oxide film 12 as a mask, the aluminum layer 11 is etched and removed so as to be patterned, and a wiring layer 11A is formed. Thereby, the transfer of a pattern defect due to halation is hardly generated in the oxide film 12 as a substratum film for the pattern 13A.

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, and more particularly to an improvement of a method of forming a wiring used in a semiconductor device which has been highly miniaturized.

[0002]

2. Description of the Related Art A conventional method of manufacturing a semiconductor device will be described below with reference to FIGS. First, as shown in FIG. 8, LOCOS is formed on the Si substrate (1).
After forming a selective oxide film (2) for element isolation by (Local Oxidation of Silicon) method, a polysilicon layer is selectively formed on the selective oxide film (2) to form a polysilicon gate (3). BPSG to be an interlayer insulating film on
After forming the [Boro-Phoso Silicate Glass] film (4), an aluminum layer (5) is formed on the entire surface.

Next, a resist is applied to the entire surface to form a resist film (6), and the resist film (6) is exposed using the photomask (7) as a mask. Next, the resist film (6) is developed to remove the exposed area, and a resist pattern (6A) is formed as shown in FIG. After that, the aluminum layer (5) was etched and removed by using the resist pattern (6A) as a mask and patterned to form a wiring layer made of aluminum.

[0004]

However, the above-mentioned conventional method has the following problems. That is, when the resist film (6) is exposed, a step is formed in the aluminum layer (5) due to the selective oxide film (2) and the polysilicon gate (3) being formed. This step difference becomes relatively large with miniaturization.

Therefore, due to this step, in the exposure step for forming the resist pattern (6A), the diffused reflection of the exposure light on the surface of the aluminum layer (5) as shown in FIG. Since the exposure state in the resist film (6) becomes non-uniform, as shown in FIG. 9, the resist pattern (6A)
The shape becomes uneven so that a desired shape as an etching mask cannot be obtained.

Therefore, by etching the aluminum layer (5) using the resist pattern (6A) having such a non-uniform shape as a mask, the non-uniform pattern is transferred onto the aluminum layer (5). , The problem that the correct size aluminum wiring layer cannot be obtained,
Alternatively, depending on the case, there is a great problem in reliability of the aluminum wiring that the wire is broken or a state close to it.

Therefore, countermeasures such as exposure using a resist containing a light absorber have been taken against halation, but this is still insufficient depending on the size of the step difference in the base, and the adverse effects of halation are completely eliminated. Could not be deterred. In addition, measures were taken to suppress the effect of halation by forming a reflection prevention film such as a TiN film or amorphous silicon film on the aluminum layer.
In order to carry out this, special equipment such as a sputtering apparatus for film deposition is required, and thus there is a situation that it is not easy to carry out.

[0008]

The present invention has been made in view of the above-mentioned conventional drawbacks, and as shown in FIGS. 1 to 5, a selective oxide film (10B), a wiring layer ( 10
C) is sequentially formed, and then an interlayer insulating film (10
D), a step of sequentially forming an aluminum layer (11),
Forming an oxide film (12) on the aluminum layer (11) and then forming a light absorber containing resist film (13) on the oxide film (12); and the light absorber containing resist film (13). After exposing a desired region of (1) to form a resist pattern (13A) by development, and patterning by etching / removing the oxide film (12) using the resist pattern (13A) as a mask; A step of forming a wiring layer (11A) by etching and removing the aluminum layer (11) using the resist pattern (13A) and the patterned oxide film (12A) as a mask. It is possible to easily form a wiring layer of a desired shape by using existing equipment while suppressing the adverse effect of halation due to the step difference of a highly reflective film such as a film. There is provided a method of manufacturing a semiconductor device comprising a capacity.

[0009]

[Operation] According to the method for manufacturing a semiconductor device of the present invention, as shown in FIGS.
After forming the oxide film (12) on the
2) A resist film containing a light absorber (13) is formed thereon, and a desired region of the resist film containing a light absorber (13) is exposed. After development to form a resist pattern (13A), the resist pattern (13A) is used as a mask to form an oxide film (12)
Is patterned by etching and removing the resist pattern (13A) and the patterned oxide film (12).
A) is used as a mask to etch and remove the aluminum layer (11) for patterning to form the wiring layer (11).
A) is formed.

Therefore, the light-absorbing agent-containing resist film (13)
Even if the shape of the resist pattern becomes non-uniform due to halation during the exposure step, the bottom layer of the light-absorbing agent-containing resist film (13) is hardly affected by the halation during the exposure. Oxide film (1
During etching when patterning 2), pattern defects due to halation are hardly transferred to the oxide film (12) of the base film of the resist pattern (13A).

As a result, even if the resist pattern (1
Even if 3A) has a non-uniform shape due to the effect of halation, the pattern having the non-uniform shape is not transferred to at least the patterned oxide film (12A), and a pattern having a correct size is transferred. Become. Therefore, the resist pattern (13A) and the patterned oxide film (1
By using the two-layer film of 2A) as a mask when etching the aluminum layer (11), a defective pattern due to the effect of halation is not transferred to at least the aluminum layer (11), and a good shape is obtained. Moreover, it becomes possible to form the wiring layer (11A) with high processing dimension accuracy.

[0012] Further, like the measures for forming the antireflection film such as the TiN film and the amorphous silicon film on the aluminum layer, the above effect can be obtained without requiring special equipment such as a sputtering device for film deposition. Therefore, there is also an advantage that it can be easily implemented with existing equipment. Further, in the method for manufacturing a semiconductor device according to the present invention, after forming an oxide film (12) having a film thickness which reduces the reflectance on the surface on the aluminum layer (11), the oxide film (12) is formed. ). Since the resist film containing a light absorber (13) is formed on
The reflectance of the base film of the resist film containing a light absorber (13) is reduced, and the resist film containing a light absorber (1) by halation is reduced.
Since the adverse effect on exposure of 3) can be reduced to some extent, it becomes even more reliable to form a wiring layer having a good shape and high processing dimensional accuracy.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a semiconductor device according to an embodiment of the present invention will be described below with reference to the drawings. First,
As shown in FIG. 1, after a selective oxide film (10B) for element isolation is formed on a Si substrate (10A) by a LOCOS method, a polysilicon layer is formed thereon and patterned to form a polysilicon gate ( 10C), and a BPSG film (10D) to be an interlayer insulating film is formed thereon, and then an aluminum layer (1
1) is formed by the sputtering method.

Next, the temperature is 400 ° C., the pressure is 2.2 Torr,
HF (High Frequency) power 1kW, LF (Low Freq
uency) Flow rate 200cc / mi under the condition of power 0kW
n SiH4, flow rate 3150 cc / min N2, flow rate 600
A film thickness of 2000 to 3000 is formed on the aluminum layer (11) by using 0 cc / min of N 2 O gas as a reaction gas.
Å, preferably an oxide film (12) with a film thickness of 2900Å is formed by the plasma CVD method, and a photoresist containing a light absorbing agent is applied to the entire surface to form a light absorbing agent containing resist film (13) with a thickness of about 1 μm.

Then, as shown in FIG. 2, the photomask (14) is used as a mask to expose a desired region of the light-absorbing agent-containing resist film (13) using i-line having a wavelength λ = 356 nm. Next, the light-absorbing agent-containing resist film (13) is developed, and the exposed region is removed to form a resist pattern (13A) as shown in FIG.

Then, as shown in FIG. 4, CHF with a flow rate of 75 SCCM is used by using the resist pattern (13A) as a mask.
The oxide film (12) is patterned by etching and removing the oxide film (12) under the conditions of RF power of 800 W and pressure of 70 mTorr using O 2 gas with 3 gas and a flow rate of 25 SCCM. In the above exposure step, the resist pattern (13) is formed by halation during the exposure step of the light absorber containing resist film (13).
Even if the shape of A) becomes defective, the lowermost layer of the light-absorbing agent-containing resist film (13) is hardly affected by halation during exposure at that time.
During etching for patterning 2), a defective pattern is not transferred to the oxide film (12) of the base film due to halation.

Next, the oxide film (12A) and the resist pattern (13) which have been patterned through the above-mentioned exposure process.
With A) as a mask, flow rate 180SCCM of SiCl4 gas,
Wiring as shown in FIG. 5 is obtained by etching and removing the aluminum layer (11) under the conditions of RF power of 1.3 kW and pressure of 15 Pa using Cl 2 gas with a flow rate of 23 SCCM and He gas with a flow rate of 20 SCCM. Layer (11A)
To form.

In the above etching process, as described above, the defective pattern is hardly transferred to the oxide film (12) of the base film by the halation, and the oxide film: resist etching rate ratio at the time of aluminum etching. Is about 1: 3 to 4 and the oxide film is less likely to be scraped than the resist. Therefore, at the time of etching the aluminum layer (11) using the two-layer film as a mask, at least the defective pattern is present in the aluminum layer (11). It is possible to form the wiring layer (11A) having a pattern that is not transferred and has high processing dimension accuracy.

Further, in the method of the present embodiment, a special anti-reflection film such as a sputtering apparatus for film formation is used as a measure for forming an antireflection film such as a TiN film or an amorphous silicon film on an aluminum layer to suppress halation. Since the above effects can be contained without requiring equipment, there is also an advantage that it can be easily implemented with existing equipment. Furthermore, in the method for manufacturing a semiconductor device according to the present embodiment, since the oxide film (12) having a film thickness of 2900Å is formed on the aluminum layer (11), the reflectance of i-line on this surface is The thickness is reduced from 92% in the case of thickness = 0Å to about 84%.

6 and 7, the oxide film (1) which is the base film of the light absorbing agent-containing resist film (13), which is the basis of this fact, is shown in FIG.
2) An example of the computer simulation result showing the relationship between the reflectance on the surface and the film thickness of the oxide film (12) is shown. Here, the exposure light uses the i-line (λ = 356 nm) and the g-line (λ = 435 nm), respectively. As shown in FIG. 6, in the exposure using the g-line, when the oxide film (12) was not present (film thickness = 0), the reflectance was considerably high, about 92%. Film thickness is, for example, 2200Å
It has been shown that it can be reduced to about 84% by setting it to about 3600Å.

In the exposure using i-line, the oxide film (1
When there is no 2) (film thickness = 0), the reflectance was similarly about 92%, but by adjusting the thickness of the oxide film (12) to about 1700Å or 2900Å, it reaches about 84%. It has been shown that it can be reduced. From the above simulation results, the light-absorbing agent-containing resist film (1
The film thickness of the oxide film (12) of the underlayer of 3) is, for example, 2200Å or 3600Å when the exposure light is the i-line and 1700Å or 290 when the exposure light is the g-line.
It was shown that by performing exposure at 0Å, the reflectance on the surface can be reduced from 92% when the film thickness is 0Å to 84%.

As described above, by adjusting the film thickness of the oxide film (12), the reflectance on the surface is reduced and the adverse effect of halation on the light-absorbing agent-containing resist film (13) on exposure is reduced. Therefore, it becomes even more reliable to form a wiring layer having a good shape and high processing dimensional accuracy. The above computer simulation method will be briefly described. In this method, the refractive index, the absorption coefficient and the film thickness of the oxide film (12), the aluminum layer (11) and the like are taken into consideration, and it is based on the simulation model described in detail in the following documents.

By PH Berning: “Theory and calculati
on of Optical Thin Films ”, Physics of Thin Films,
Vol-1, George Hass ed., New York; Academic Press (196
3) pp.69-121: Further, in this embodiment, the i-line is used as the exposure light of the light-absorbing agent-containing resist film (13), but the present invention is not limited to this, and the film thickness of the oxide film (12) can be changed. Eg 2
The same effect can be obtained when the exposure is performed using g-line with a thickness of about 200 Å or 3600 Å, or even when the exposure is performed using an excimer laser or the like, the same effect can be obtained by selecting an appropriate film thickness.

[0024]

As described above, according to the method of manufacturing a semiconductor device of the present invention, after the oxide film (12) is formed on the aluminum layer (11), the oxide film (1) is formed.
2) A resist film containing a light absorber (13) is formed on the resist film, and a desired region of the resist film containing a light absorber (13) is exposed and developed to form a resist pattern (13A), and then a resist pattern (13A). Oxide film (12)
Is patterned by etching and removing the resist pattern (13A) and the patterned oxide film (12).
The aluminum layer (11) is etched and removed using A) as a mask to pattern the aluminum layer (11).
Since 1A) is formed, the pattern having the non-uniform shape is not transferred to at least the patterned oxide film (12A), and the pattern having the correct size is transferred.

As a result, the resist pattern (13A)
A defective pattern due to the effect of halation is not transferred to the aluminum layer (11), which is the base film of the two-layer film including the patterned oxide film (12A) and the wiring layer (11A) with high processing dimension accuracy is formed. It becomes possible to do. Also, as a measure to form an antireflection film such as TiN film or amorphous silicon film on the aluminum layer,
Since the above effects can be contained without requiring special equipment such as a sputtering apparatus for film deposition, there is also an advantage that it can be easily carried out with existing equipment.

[Brief description of drawings]

FIG. 1 is a first cross-sectional view illustrating a method of manufacturing a semiconductor device according to an embodiment of the invention.

FIG. 2 is a second cross-sectional view illustrating the method for manufacturing the semiconductor device according to the embodiment of the invention.

FIG. 3 is a third cross-sectional view illustrating the method for manufacturing the semiconductor device according to the embodiment of the invention.

FIG. 4 is a fourth sectional view illustrating the method for manufacturing the semiconductor device according to the embodiment of the invention.

FIG. 5 is a fifth cross-sectional view illustrating the method for manufacturing the semiconductor device according to the embodiment of the invention.

FIG. 6 is a first graph showing the results of a computer simulation for explaining the function and effect of the present invention.

FIG. 7 is a second graph showing the result of a computer simulation for explaining the effect of the present invention.

FIG. 8 is a first cross-sectional view illustrating the method for manufacturing the semiconductor device according to the conventional example.

FIG. 9 is a second cross-sectional view illustrating the method for manufacturing the semiconductor device according to the conventional example.

Claims (2)

[Claims] 1. A selective oxide film (10) on a substrate (10A).
B), a wiring layer (10C) are sequentially formed, and then an interlayer insulating film (10D) and an aluminum layer (11) are sequentially formed thereon, and an oxide film (12) is formed on the aluminum layer (11). ) Is formed, and then a resist film containing a light-absorbing agent (13) is formed on the oxide film (12), and a desired region of the resist film containing a light-absorbing agent (13) is exposed and then developed. Forming a resist pattern (13A) using the resist pattern (13A) as a mask and etching and removing the oxide film (12) to perform patterning; and the resist pattern (13A) and the patterned oxide film. The aluminum layer (11) is etched and removed using (12A) as a mask to form a wiring layer (11
A) is formed, and the manufacturing method of the semiconductor device characterized by the above-mentioned. 2. A selective oxide film (10) on a substrate (10A).
B), a wiring layer (10C) is sequentially formed, and then an interlayer insulating film (10D) and an aluminum layer (11) are sequentially formed thereon, and reflection on the surface of the aluminum layer (11) is performed. After forming the oxide film (12) having a film thickness that reduces the
A step of forming a light absorbing agent-containing resist film (13) on the oxide film (12); and after exposing a desired region of the light absorbing agent-containing resist film (13), development is performed to form a resist pattern (13A). Forming and patterning by etching / removing the oxide film (12) using the resist pattern (13A) as a mask; and using the resist pattern (13A) and the patterned oxide film (12A) as a mask The aluminum layer (11) is etched and removed to form a wiring layer (11
A) is formed, and the manufacturing method of the semiconductor device characterized by the above-mentioned.