JP2003273004A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a resist film to be easily improved in adhesion to an etching object film. <P>SOLUTION: A metal film 11, as an object film of etching, is formed on the etched surface of a wafer 10 in a film forming process, a negative resist film 12a of cyclized rubber of high chemical resistance and serving as a resist adhesion booster is formed on the surface of the metal film 11, a part of the negative resist film 12a except its part below a resist film 13 is removed by irradiation with O<SB>2</SB>plasma in a pretreatment carried out prior to etching process, and the metal film 11 and the positive resist film 13 are subjected to etching as they are kept in close contact with each other through the intermediary of the negative resist film 12a. <P>COPYRIGHT: (C)2003,JPO

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 enhances the adhesion of a resist film to a film to be etched during wet etching.

[0002]

2. Description of the Related Art In wet etching with a chemical solution after development in manufacturing a semiconductor device, an exposed region of a film to be etched which is not covered with a resist film is removed.
That is, when the exposed film to be etched that is not covered with the resist film is removed, as shown in the etching cross section in FIG. 3, the oxidation corresponding to the portion covered with the resist film 3 on the wafer 1 such as SiO ₂ is performed. The metal film 2 which is a film to be etched such as silicon or Al (aluminum) is left.

Here, it is necessary to control the angle of the taper to be formed on the metal film 2 so that the film made of a wiring material, an insulating material, or the like can adhere well, but usually the etching time is variable. I am trying to control it by making it. That is, by changing the etching time, for example, as shown in FIG.
The amount of chemicals soaked into the lower part of the sheet (hereinafter referred to as the undercut amount) (B) is adjusted.

By the way, the undercut amount (B)
Depends not only on the etching time but also on the adhesion of the resist film 3 to the metal film 2. That is, even if the etching time of wet etching is the same, if the adhesiveness of the resist film 3 to the metal film 2 is weak, the undercut amount (B) becomes large. Incidentally, if the undercut amount (B) becomes larger than necessary, a desired pattern cannot be formed. Further, since the contact area between the metal film 2 and the resist film 3 is reduced, the resist film 3 may be peeled off, which adversely affects the processing in the subsequent steps.

Therefore, in order to improve the adhesion of the resist film 3, as a pretreatment for resist application, for example, HMDS.
This is dealt with by treatment with an adhesion enhancer such as (hexamethyldisilane).

[0006] This is because BP is used in the film forming process.
SG (Boro-Phospho-Silicate-Glass) and SOG (Spin-on-
The same can be said when a glass film such as (Glass) is formed. That is, as shown in FIG. 5, contact holes 6 are formed in the glass film 5 between the resist films 3 on the wafer 1 by wet etching in the etching process.
Is formed, a taper is formed for the same reason as above so that the film 2 made of the above-mentioned wiring material, insulating material, or the like is favorably attached to the portion 2a surrounded by the dotted circle. It has become.

[0007]

By the way, when the resist film 3 described above is a positive resist represented by a novolac type resin suitable for mass production, it is compatible with the metal film 2 and the glass film 5 which are films to be etched. Depending on the metal film 2
Although the adhesiveness with the glass film 5 and the glass film 5 is reduced, the decrease in the adhesiveness due to the compatibility is avoided by selecting an adhesion enhancer suitable for the metal film 2 and the glass film 5.

However, the chemical change due to the fluorine-based chemicals used for etching the oxide film may cause swelling or the like in the resist film 3 at the contact interface with the metal film 2 or the glass film 5, and the metal film 2 or Despite the selection of the adhesion enhancer suitable for the glass film 5, there is a problem that the adhesion with the metal film 2 and the glass film 5 is deteriorated.
By the way, when such swelling occurs, the above-mentioned undercut amount (B) becomes too large even if the etching time and the amount of chemicals are set appropriately, which causes peeling and floating of the resist film 3. Therefore, the quality of the semiconductor device is deteriorated.

The present invention has been made in view of such circumstances, and it is possible to provide a method of manufacturing a semiconductor device capable of easily improving the adhesion of a resist film to a film to be etched. To do.

[0010]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, the method comprising the steps of forming a film to be etched, applying a cyclized rubber resin, and resist. And a step of forming a resist in a predetermined pattern, a step of removing the exposed region of the cyclized rubber resin, and a step of wet etching the film to be etched.

Further, the step of removing the exposed region of the cyclized rubber resin can be carried out by irradiation with O ₂ plasma.

A method of manufacturing a semiconductor device according to a third aspect is the method of manufacturing a semiconductor device, wherein the step of forming a film to be etched, the step of applying a negative resist, the step of applying a positive resist, and the positive resist. Is formed into a predetermined pattern, a step of removing the exposed region of the negative resist, and a step of wet-etching the film to be etched are featured.

Further, the step of removing the exposed region of the negative resist can be performed by irradiation with O ₂ plasma.

In the method of manufacturing a semiconductor device according to the present invention, the resist film is brought into close contact with the film to be etched through the cyclized rubber resin, and the resist at the contact interface with the film to be etched is affected by chemicals during etching. The cyclized rubber resin suppresses the deterioration of the adhesiveness due to the chemical change of the film.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

(First Embodiment) FIG. 1 is a diagram for explaining a first embodiment of a method for manufacturing a semiconductor device according to the present invention.

In the first embodiment, the film to be etched formed on the wafer in the film forming step is a metal film made of a metal material such as silicon oxide or Al (aluminum), and a resist is adhered to the surface of the metal film. After applying a thin film of the sex enhancing agent, a positive resist typified by a novolac type resin suitable for mass productivity is applied, and then exposure, development, O ₂ plasma irradiation, and wet etching are performed.

First, an example of semiconductor device manufacturing up to the etching step will be described. After the wafer 10 made of SiO ₂ or the like is cleaned in the cleaning step shown in FIG. Wafer 1 in the film forming process shown in
A metal film 11 as a film to be etched made of a metal material such as silicon oxide or Al (aluminum) is formed on the surface on which the circuit of 0 is arranged.

When the metal film 11 is formed, the metal film 11 is applied in the resist adhesion enhancer coating step shown in FIG. 1 (c).
A cyclized rubber resin 12 is thinly applied to the surface of the. When applying the cyclized rubber resin 12, it is desirable to make the thickness thinner than the positive resist formed later. In the present embodiment, the thin coating is performed by using a spin coater or the like. The cyclized rubber resin 12 is a negative resist, and the negative resist film 12a is formed on the surface of the metal film 11 by applying the negative resist. The negative resist film 12a has chemical resistance during etching, and can reduce the amount of undercut generated in the wet etching process. The film thickness can be set to, for example, about 500Å.

After formation of the negative resist film 12a, FIG.
In the resist coating step shown in (d), a positive resist typified by a novolac type resin suitable for mass productivity is applied, and the positive resist film 13 is formed on the surface of the negative resist film 12a.
Is formed. A spin coater or the like can be used for applying the positive resist. Incidentally, it is also possible to carry out baking after applying the positive resist to promote evaporation of the solvent. Further, it is also possible to accelerate the evaporation of the solvent by baking after applying the negative resist.

After the positive resist film 13 is formed, FIG.
When the circuit pattern is printed from the surface of the positive resist film 13 by the stepper using a mask (not shown) in the exposure step shown in FIG. 1, it is baked in the exposure step by the development in the developing step shown in FIG. A positive resist film 13 which is a resist mask corresponding to the circuit pattern is formed.

When the positive resist film 13 is formed, FIG.
O in the resist adhesion enhancing film removing step shown in (g)
By the O ₂ plasma irradiation in the ₂ plasma irradiation step, the negative resist film 12 other than below the positive resist film 13 is exposed.
a is removed. Although the positive resist is also removed by the O ₂ plasma irradiation, by making the coating film thickness of the negative resist thinner than the coating film thickness of the positive resist,
At the stage when the removal of the exposed negative resist in the O ₂ plasma irradiation step is completed, the positive resist remains. That is, as described above, the negative resist film 12a has chemical resistance at the time of etching and cannot be removed by the chemical used at the time of etching, so it is necessary to remove it in advance.

When the negative resist film 12a other than under the positive resist film 13 is removed, only the portions corresponding to the negative resist film 12a and the positive resist film 13 are wet-etched in the etching process shown in FIG. 1 (h). The metal film 11 is left. Here, during wet etching, corrosion is performed by a fluorine-based chemical that is usually used for oxide film etching. At this time, since the negative resist film 12a having chemical resistance is present at the adhesion interface between the positive resist film 13 and the metal film 11,
Negative resist film 12a at the adhesion interface with the metal film 11
No changes such as swelling occur.

As a result, the adhesiveness of the positive resist film 13 to the metal film 11 is maintained satisfactorily without lowering, so that the chemical undercut amount (B) below the positive resist film 13 is properly adjusted. Therefore, a desired pattern can be formed. Moreover, etching is performed without peeling or rising of the positive resist film 13. Due to such etching, the positive resist film 13 is not peeled off or lifted up, so that a high quality semiconductor device is manufactured.

As described above, in the first embodiment, the surface of the metal film 11, which is the film to be etched formed on the surface to be etched of the wafer 10 formed in the film forming step, has chemical resistance. A cyclized rubber-based negative resist film 12a which is a resist adhesion enhancer has been formed, and the negative resist film 12a other than below the resist film 13 was removed by O ₂ plasma irradiation as a pretreatment of the etching process.

As a result, at the time of etching, the metal film 1 is formed via the negative resist film 12a having chemical resistance.
Since the positive resist film 13 is adhered to the negative resist film 1, the negative resist film 12a at the adhesion interface with the metal film 11 due to the chemical is used even when a fluorine-based chemical that is commonly used for oxide film etching is used. Since no change such as swelling occurs in the positive resist film 1 for the metal film 11.
The adhesiveness of 3 can be easily improved.

Further, by improving the adhesion of the positive resist film 13 to the metal film 11, the undercut amount (B) of the chemical below the positive resist film 13 can be adjusted appropriately, and the positive resist film can be adjusted. Wet etching can be performed without peeling or rising of 13.

Further, since the negative resist film 12a other than under the resist film 13 is removed by O ₂ plasma irradiation as a pretreatment of the etching process, wet etching of the metal film 11 can be performed without any trouble.

(Second Embodiment) FIG. 2 is a view for explaining a second embodiment of the method of manufacturing a semiconductor device in the case where the film to be etched is a glass film in the film forming process of FIG. FIG. In the figures described below,
The same parts as those in FIG. 1 are designated by the same reference numerals, and overlapping description will be omitted.

In the second embodiment, the film to be etched formed on the wafer in the film forming step is a glass film. That is, FIG. 2B after the cleaning step of FIG.
In the film forming process shown in FIG.
A glass film 14 which is an interlayer insulating film of PSG, NSG, BSG, SOG, or the like is formed.

When the glass film 14 is formed, FIG.
In the resist adhesion enhancing agent applying step shown in (1), the negative resist film 12a is formed by thinly applying the cyclized rubber resin 12 to the surface of the glass film 14. Here, the film thickness of the negative resist film 12a can be set to, for example, about 500 Å as in the above. Incidentally, it is also possible to carry out baking after applying the positive resist to promote evaporation of the solvent. In addition, baking is performed after applying the negative resist,
It is also possible to accelerate the evaporation of the solvent.

The negative resist film 12 is formed on the surface of the glass film 14.
After the formation of a, the positive resist film 13 is formed in the same manner as described above in the resist coating step shown in FIG. 2D, and after the circuit pattern is baked in the exposure step shown in FIG. By the development in the developing process shown in FIG. 2F, the positive resist film 13 corresponding to the circuit pattern is formed.

When the positive resist film 13 is formed, FIG.
O in the resist adhesion enhancing film removing step shown in (g)
By the O ₂ plasma irradiation in the ₂ plasma irradiation step, the negative resist film 12 other than below the positive resist film 13 is exposed.
a is removed. Although the positive resist is also removed by the O ₂ plasma irradiation, by making the coating film thickness of the negative resist thinner than the coating film thickness of the positive resist,
At the stage when the removal of the exposed negative resist in the O ₂ plasma irradiation step is completed, the positive resist remains.

When the negative resist film 12a other than under the positive resist film 13 is removed, a contact hole 15 is formed in the glass film 14 by wet etching in the etching process shown in FIG. 2 (h).
Here, in wet etching, as described above,
Corrosion is performed by the fluorine-based chemical used for oxide film etching. For example, HF, H ₂ O, CH ₃ C
An etchant containing OOH and NH ₃ can be used. At this time, since the negative resist film 12a having chemical resistance is interposed at the close contact interface between the positive resist film 13 and the glass film 14, the negative resist film 12a at the close contact interface with the glass film 14 is interposed. No changes such as swelling occur.

As a result, the adhesiveness of the positive resist film 13 to the glass film 14 is maintained satisfactorily without lowering, so that the undercut amount (B) of the chemical below the positive resist film 13 is properly adjusted. Therefore, the etching is performed without peeling or rising of the positive resist film 13. Due to such etching, the positive resist film 13 is not peeled off or lifted up, so that a high quality semiconductor device is manufactured.

As described above, in the second embodiment, since the positive resist film 13 is adhered to the glass film 14 through the negative resist film 12a having chemical resistance, the fluorine-based chemicals are used in the second embodiment. Since no change such as swelling occurs in the negative resist film 12a at the contact interface with the glass film 14, the positive resist film 1 for the glass film 14
The adhesiveness of 3 can be easily improved.

Further, by improving the adhesion of the positive resist film 13 to the glass film 14, the undercut amount (B) of the chemical below the positive resist film 13 can be adjusted appropriately in the same manner as above. A desired pattern can be formed. In addition, wet etching can be performed without peeling or rising of the positive resist film 13.

Since the negative resist film 12a other than under the resist film 13 is removed by the O ₂ plasma irradiation as a pretreatment of the etching process, the wet etching of the glass film 14 can be performed without any trouble as described above. You can

Further, since the negative resist film 12a made of the cyclized rubber resin 12 used in each of the above embodiments has an antireflection effect in the ultraviolet region, an antihalation effect due to a step can be obtained. Therefore, it is possible to accurately align and focus in the exposure process. Further, the semiconductor device of the present invention is not limited to one formed on a semiconductor substrate, and wiring on the substrate,
It includes those forming transistors and diodes and includes, for example, liquid crystal displays.

[0040]

As described above, according to the method of manufacturing a semiconductor device of the present invention, the resist film is brought into close contact with the film to be etched through the cyclized rubber resin, and the film to be etched by chemicals during etching is used. Since the cyclized rubber-based resin suppresses the deterioration of the adhesiveness due to the chemical change of the resist film at the adhesive interface with, the adhesiveness of the resist film to the etching target film can be easily improved.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a first embodiment according to a method for manufacturing a semiconductor device of the present invention.

FIG. 2 shows a second method of manufacturing a semiconductor device in which a film to be etched is a glass film in the film forming process of FIG.
It is a figure for explaining the embodiment of.

FIG. 3 is a diagram for explaining an etching process in a conventional method for manufacturing a semiconductor device.

FIG. 4 is a diagram for explaining a profile of an etching cross section by wet etching in a conventional method for manufacturing a semiconductor device.

FIG. 5 is a diagram for explaining a profile of an etching cross section by wet etching in a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

10 wafers 11 Metal film 12 Cyclized rubber resin 12a Negative resist film 13 Positive resist film 14 glass film 15 contact holes

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/302 104H 21/30 572A F term (reference) 2H025 AA14 AB16 AD03 DA13 DA35 FA28 FA40 2H096 AA25 BA01 BA09 HA17 HA30 KA04 KA06 KA15 5F004 AA04 DA26 DB00 DB26 EA02 EA10 5F046 HA01 LA18 MA12 NA02

Claims (4)

[Claims] 1. A method of manufacturing a semiconductor device, which comprises a step of forming a film to be etched, a step of applying a cyclized rubber resin, a step of applying a resist, and a step of forming the resist in a predetermined pattern. A method of manufacturing a semiconductor device, comprising: a step of removing an exposed region of the cyclized rubber resin; and a step of wet etching the film to be etched. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the step of removing the exposed region of the cyclized rubber resin is performed by O ₂ plasma irradiation. 3. A method of manufacturing a semiconductor device, comprising: forming a film to be etched; applying a negative resist; applying a positive resist; and forming the positive resist in a predetermined pattern, A method of manufacturing a semiconductor device, comprising: a step of removing an exposed region of the negative resist; and a step of wet etching the film to be etched. 4. The method of manufacturing a semiconductor device according to claim 1, wherein the step of removing the exposed region of the negative resist is performed by O ₂ plasma irradiation.