JPH0274948A - Method for applying resist film - Google Patents

Abstract

PURPOSE:To suppress the generation of resist voids by dropping an aq. org. alkaline soln. onto the surface of a semiconductor substrate on which a lower layer resist film and intermediate SOG film are applied and formed while rotating the substrate to clean the surface, then applying and forming an upper resist film thereon. CONSTITUTION:The lower layer resist film 2 and the intermediate SOG (Spin on glass) film 3 are successively applied on the semiconductor substrate 1 and are subjected to a baking treatment. While this substrate 1 is kept rotated thereafter, the aq. org. alkaline soln. 7 is dropped (or sprayed) to the surface thereof, i.e. the surface of the intermediate SOG film 3 inclusive of the exposed part 2a of the lower layer resist film 2 to clean the surface. The final upper layer resist film 4 is then applied and formed on the intermediate SOG film 3 inclusive of the exposed part 2a cleaned by the aq. org. alkaline soln. 7. The adhesive property of the upper layer resist film 4 is well improved in this way and the generation of the resist voids on the intermediate SOG film 3 is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resist film coating method, and more specifically, the present invention relates to a method for applying a resist film, and more specifically, a method for applying a resist film using a three-layer resist film, which is commonly used in the manufacturing process of LSI (high-density semiconductor integrated circuit device). The present invention relates to an improvement in a method for coating a resist film comprising:

[Conventional technology]

A conventional method for applying this type of resist film.

In this 1, the appearance of the entire resist layer obtained by the method of coating a resist film consisting of three layers, a lower layer, an intermediate layer, and an upper layer is shown in FIGS. 5(a) and 5(b), and in this case,
5(a) is a longitudinal sectional view of the entire resist layer, and FIG. 5(b) is a plan view thereof.

That is, in the conventional three-layer resist film shown in FIGS. 5(a) and 5(b), reference numeral 1 represents a semiconductor substrate, and 2, 3. and 4 are a lower resist film and an intermediate SOG (spin on glass) which are sequentially coated and formed on this semiconductor substrate 1.
5 indicates a relatively huge foreign substance existing on the semiconductor substrate l and protruding upward through each of the layers 2, 3.4, and 6 indicates the lower resist film 2.
From the inside to the middle SOG film 3, and also the middle SOG@
These are relatively fine foreign substances that exist independently on each of the three surfaces.

As seen in these Figures 5(a) and (b),
In the case of the conventional method of coating a three-layer resist film on a semiconductor substrate 1, a lower resist film 2.
and when a relatively large foreign object 5 is present to the extent that it can penetrate the intermediate SOG film 3.

and/or when relatively fine foreign matter 6 exists independently on the intermediate SOG film 3, these lower resist films 2. When the upper resist film 4 is subsequently applied on the intermediate SOG film 3, foreign particles 5. and/or over a relatively large area centering on the foreign object 6, so-called
It is known that resist voids (relatively large pinholes) 8 are generated.

[Problem to be solved by the invention]

As described above, each of the three resist films 2, 3 . In the coating method of 2. and 4, a relatively large foreign material 5 is present on the semiconductor substrate l, and this foreign material 5 is deposited on the lower resist film 2. Intermediate layer SOG film 3
and/or intermediate layer SOG
If relatively fine foreign matter 6 is present on the film 3, when the upper resist film 4 is coated on each of these films 2 and 3, these foreign matter 5. And/or resist voids 8 of a relatively large area may be generated around the foreign matter 6, and the resist voids 8 may cause defects in the device itself manufactured through subsequent steps.

This invention was made to solve these conventional problems, and its purpose is to prevent the occurrence of resist voids after the coating is formed in a method for coating a resist film consisting of three layers. This made it possible to effectively suppress it. This type of resist coating method, this S, aims to provide a method for coating a resist film consisting of three layers that is applied to an LSI manufacturing process.

[Means to solve the problem]

In order to achieve the above object, a method for coating a resist film consisting of three layers according to the present invention includes coating and forming a lower resist film and an intermediate SOG film on a semiconductor substrate, and then rotating the semiconductor substrate. While cleaning, an organic alkaline aqueous solution is dropped onto the surface for cleaning treatment, and then an upper resist film is applied and formed again.

That is, the present invention provides a method for coating a resist film consisting of three layers applied to an LSI manufacturing process, in which a lower resist film and an intermediate SOG film are first sequentially coated on a semiconductor substrate, and then baked. After the treatment, while rotating the semiconductor substrate, the surface is coated with, for example, tetramethylammonium hydroxide (T
A cleaning treatment is performed by dropping an organic alkaline aqueous solution containing aqueous organic alkaline solution, etc., and then an upper resist film is applied and formed on the intermediate SOG film that has been cleaned with the organic alkaline aqueous solution. This is a method of applying a resist film.

[Function] Therefore, in the present invention, after coating and forming a lower resist film and an intermediate SOG film on a semiconductor substrate, the surfaces thereof are cleaned with an organic alkaline aqueous solution, and then an upper layer is again applied on top of these. Since the resist film is formed by coating, the adhesion of the upper resist film is favorably improved, and the generation of resist voids on the intermediate SOG film can be effectively suppressed.

〔Example〕

Hereinafter, one embodiment of the resist film coating method according to the present invention will be described in detail with reference to FIGS. 1 to 4.

1 and 2 are vertical cross-sectional explanatory diagrams each schematically showing the main steps in a method for coating a resist film consisting of three layers, a lower layer, an intermediate layer, and an upper layer, to which this embodiment is applied. 3 and 4 are schematic explanatory diagrams respectively showing different means for cleaning the surface of the intermediate layer. In the example method shown in FIGS. 1 and 2, the above-mentioned FIG. 5(a), (
The same reference numerals as in the conventional method shown in b) represent the same or corresponding parts.

That is, in the method of this embodiment, as in the case of the conventional method, when a semiconductor substrate l as a coating target on which a relatively large foreign material 5 is used is used, as shown in FIG. First, for this semiconductor substrate I,
Lower resist film 2. and intermediate SOG film 3 are sequentially applied, but at this time, the foreign matter 5 is removed from these lower resist films 2 . The SOGOsO4 of the intermediate layer will be protruded onto the surface so as to penetrate through them, and around these protrusions, a part of the lower resist film 2 will be exposed while the SOGOsO4 of the intermediate layer is separated. This portion is exposed to form an exposed portion 2a.

According to the method of this embodiment, the lower resist film 2. and intermediate SOG film 3
After sequentially applying and beta-treating the coatings 9, for example, by using the means shown in FIGS. 3 and 4 (details will be described later), while rotating the semiconductor substrate 1,
For the surface thereof, that is, the surface of the intermediate SOG film 3 including the exposed portion 2a of the lower resist film 2, an organic alkaline aqueous solution having a concentration of 2% or less, in this case, for example, 2% or less tetramethylammonium. Hydroxide (TM)
A cleaning treatment is performed by dropping (or spraying) an organic alkali aqueous solution 7 containing AH), etc.
As shown in the figure, an intermediate SOG film 3 including an exposed portion 2a that has been cleaned with this organic alkaline aqueous solution 7.
On top of this, the final upper layer resist @4 is applied and formed.

Further, the means for cleaning the surface of the intermediate SOG film 3 by dropping (or spraying) an organic alkali aqueous solution*7 may be as follows.

That is, the means shown in FIG. 3 first places the lower resist film 2. and intermediate SOG film 3
The semiconductor substrate 1 that has been sequentially coated with and baked is placed on it, and the stage 12 and thus the semiconductor substrate 1 are rotated at an appropriate speed while the inside of the cup 11 is evacuated, and then, By supplying nitrogen gas through a bubbler 14 into a tank 13 containing an organic alkaline aqueous solution 7 with a concentration of 2% or less, a gas is applied onto the intermediate SOG film 3 from the tip of a vibrator 15 connected to the tank 13. The cleaning treatment is carried out by dropping and spraying an organic alkali aqueous solution 7, and the means shown in FIG.
6 is provided, and the organic alkaline aqueous solution 7 supplied through the vibrator 15 is atomized by an ultrasonic nozzle 16 and similarly dropped and sprayed onto the intermediate SOG film 3 for cleaning treatment.

Therefore, in the resist film consisting of three layers formed by the method of this embodiment, the lower resist film 2. and intermediate SO
After sequentially applying and baking the G film 3, an organic alkali aqueous solution 7 is dropped onto the surface of the intermediate SOa@3 including the exposed portion 2a of the lower resist film 2 while rotating the semiconductor substrate l. Since the washing process is carried out by doing this, the subsequent coating formation of the upper resist film 4 is performed well, and unlike the case of the conventional method described above, the occurrence of resist voids 8 centered on foreign matter 5 is prevented. As a result, the upper resist film 4 can be coated and formed in good contact with the entire surface of the intermediate SOG film 3, including the exposed portions 2a of the lower resist 2. , and this also occurs in the case where the foreign matter 6 exists from within the lower resist film 2 onto the intermediate SOG film 3 and/or when the foreign matter 6 exists independently on the intermediate SOG film 3, as described above. It works exactly the same way.

In addition, in the above-mentioned example method, the case where a three-layer resist is applied and formed on a semiconductor substrate has been described, but the same effects and effects can be obtained even if it is applied to other cases where there is a risk of generating resist voids. Of course, it is effective.

〔Effect of the invention〕

As detailed above, according to the method of the present invention, in the resist film coating method applied to the LSI manufacturing process, first, a lower resist film and an intermediate SOG film are sequentially coated on a semiconductor substrate. After beta processing,
While rotating this semiconductor substrate, an organic alkaline aqueous solution containing, for example, tetramethylammonium hydroxide (TMAH) was dropped onto the surface of the intermediate SOG film for cleaning treatment, and then the organic alkaline aqueous solution was cleaned. Since the upper resist film is coated and formed on the intermediate SOG film, resist voids that conventionally occur on the intermediate SOG film due to the presence of foreign matter can be effectively suppressed or prevented, and as a result, There is no risk of causing fatal damage to the manufactured device,
Furthermore, since a cleaning step using an organic alkaline aqueous solution is simply added to the manufacturing process, the method has the advantage of being extremely simple and easy to implement.

[Brief explanation of the drawing]

1 and 2 schematically show in sequence the main steps in a method for coating a resist film consisting of three layers, a lower layer, an intermediate layer, and an upper layer, to which an embodiment of the present invention is applied, and a vertical cross-sectional explanation is given for each. Figures 3 and 4 are schematic explanatory diagrams respectively showing different means for cleaning the surface of the intermediate layer in the same method as above, and Figures 5(a) and 4(b)
1A and 1B are a vertical cross-sectional view and a plan view showing aspects of the entire resist film consisting of three layers, a lower layer, an intermediate layer, and an upper layer, obtained by a conventional method. ■...Semiconductor substrate, 2...Lower resist film, 2
a...Exposed part of lower resist film, 3...Middle S
OG film, 4... Upper resist film, 5.6... Foreign matter, 7... Organic alkaline aqueous solution, 8... Resist void. Agent Masuo Oiwa

Claims (1)

[Claims] In a method for coating a resist film consisting of three layers applied to an LSI manufacturing process, first, on a semiconductor substrate,
A lower resist film and an intermediate SOG film are sequentially applied,
After baking, the semiconductor substrate is rotated and an organic alkaline aqueous solution containing, for example, tetramethylammonium hydroxide is dropped onto the surface for cleaning treatment. A resist film coating method characterized in that an upper resist film is formed by coating on the intermediate SOG film which has thus been cleaned.