JPH03250619A - Pattern formation - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for forming a pattern in a large-scale integrated circuit.

[Prior Art] FIG. 2 is a side sectional view showing this type of conventional pattern forming method, and in the figure (1) is a stepped substrate. (2
) is a lower resist layer coated and baked on the stepped substrate (1) so that the top surface is flat;
Contains a pigment that absorbs the exposure light to prevent reflection from the surface. (4) is an intermediate layer obtained by applying and baking SOC (spin-on glass) on the lower resist layer (2);
(5) is an upper resist layer that is thinly coated and betated on the intermediate layer (4).

A method of processing a resist having such an arrangement is given as follows.

After forming the stepped substrate (1) to the upper resist layer (5) as shown in FIG. 2(a), the upper resist layer (5) is exposed and developed to form a pattern as shown in FIG. 2(b). . Next, as shown in (C), using the upper resist layer (5) as a mask, a gas containing CF4 as a main component is applied to the intermediate layer (4).
anisotropic plasma etching.

Furthermore, as shown in (d), the intermediate layer (4) is used as a mask and 0. The lower resist layer (2) is anisotropically etched in a gas atmosphere containing gas as a main component. Finally, as shown in (e), the step substrate (1,) is etched using the lower resist layer (2) as a mask.

[Problems to be Solved by the Invention] In the conventional pattern forming method as described above, in order to increase the etching selectivity with respect to the stepped substrate (1), the lower resist layer (2) is mainly composed of a novolac resin. Only materials were used. Therefore, O shown in (d),
In the anisotropic etching step using gas, the etching rate becomes small, and therefore, this step (d) becomes the main cause of lowering the overall through-foot, making it difficult to put the device into practical use.

The present invention was made to solve this problem, and it is possible to increase the etching rate for the lower resist layer and improve the through-foot without impairing the etching selectivity when etching with the stepped substrate. The purpose of this invention is to obtain a method for forming a pattern.

[Means for Solving the Problems 1] The pattern forming method according to the present invention includes etching a PMMA film with a high etching rate using anisotropic plasma on a substrate to be processed.
A process of applying and baking a first lucist layer mainly composed of Lungst layer, and applying a second resist layer mainly composed of a novolac resin that has resistance to anisotropic plasma etching and has high absorption at the exposure wavelength on the second Lundst layer. a step of baking, a step of applying SOG (spin-on glass) on the second resist layer and baking it, and a step of baking the second resist layer;
A step of applying and baking a third resist layer mainly composed of novolak resin and having a high resolution on the second layer of G.
A process of patterning the resist layer by exposure and development, and S using the patterned third resist layer as a mask.
a step of processing OG by anisotropic plasma etching, a step of processing a second resist layer and a second resist layer by anisotropic plasma etching using the processed SOG as a mask, and a step of processing the processed second resist layer and second resist layer. This process consists of processing a substrate to be processed using the layer as a mask.

[Function] In this invention, the lower resist is divided into two layers, the first layer is coated with PMMA and then baked, and the second layer is coated with a novolac resin containing a conventional dye that absorbs the exposure wavelength as a main component. Apply a resist and bake. At this time, by using PMMA in the lower first layer, planarization and etching rate are increased.

[Example] FIG. 1 is a side sectional view showing an example of the pattern forming method according to the present invention, and (1) is the same as described above. (2') is a first etching layer mainly composed of PMMA which has a high etching rate in anisotropic plasma etching and is coated and baked on the stepped substrate (1). (3') is a second resist layer coated on the second resist layer (2'), which has a small etching effect during anisotropic plasma etching and is baked, and contains a dye that absorbs the exposure wavelength. . (4') is the second resist layer (
3') is a 5oG (spin-on glass) coated and baked, and (5') is a high-resolution resist that is thinly coated and baked as SOG (4').

The method for coating these resists is as follows.

First, a resist layer (2') mainly composed of PMMA having a high etching rate in anisotropic plasma etching is coated on the step substrate (1) until the upper surface of the resist becomes flat, and then baking is performed. Next, the first Lujist layer 2')
The thickness of the step substrate (1) is the sum of the thickness of the second resist layer (3') containing a dye that absorbs the exposure wavelength and having a small etching rate of anisotropic plasma etching on the 11278th layer (2'). The engineering.

After the coating is applied until it has masking properties against scratching, baking is performed. Furthermore, after applying SOC (4'), baking is performed, and a high-resolution resist (
Apply a thin layer of 5') and bake.

The resist (5') thus applied as shown in FIG. 1(a) is first exposed and developed to form a pattern as shown in FIG. 1(b). Next, using the patterned resist (5') as a mask, as shown in (C),
SOG (4'
) is subjected to plasma etching.

Furthermore, using the etched SOG (4') as a mask, the first and second resist layers (2') are formed as shown in (d).
, (3') 0. Anisotropic etching is performed using a gas whose main component is gas. Finally, using each etched resist layer (2') and (3') as a mask,
Etching is performed on the stepped substrate (1) as shown in (e).

[Effects of the Invention] As explained above, the present invention includes a step of applying and etching a 11278th layer mainly composed of PMMA having a high etching rate using anisotropic plasma on a substrate to be processed;
On the second resist layer, a step of applying a second resist layer mainly composed of a noholac phase resin that has anisotropic plasma etching resistance and has high absorption at the exposure wavelength is provided, so that the 11278th layer flattens the etching. Furthermore, the etching rate can be increased, and the masking properties for substrate etching can be obtained by the presence of the second resist, so that patterns can be formed at high throughput.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention, and FIG. 2 is a side sectional view showing a conventional pattern forming method. In the figure, (1) is a stepped substrate (substrate to be processed), (2'
) is the 11278th layer, (3') is the second resist layer, (4
') is SOG, and (5') is resist. Note that the same reference numerals in each figure indicate the same or corresponding parts. Kō1 Figure 51 List

Claims (1)

[Claims] A step of applying and baking a first resist layer mainly composed of PMMA having a high etching rate using anisotropic plasma on the substrate to be processed; A step of applying and baking a second resist layer mainly composed of a novolac resin that has a high absorption of A step of applying and baking a third resist layer containing resin as a main component and having a high resolution, a step of patterning the third resist layer by exposure and development, and a step of changing the SOG using the patterned third resist layer as a mask. Processing by directional plasma etching and the processed SOG
a step of processing the second resist layer and the first resist layer by anisotropic plasma etching using as a mask; and a step of processing the substrate to be processed using the processed first resist layer and the second resist layer as a mask. A pattern forming method characterized by: