JPH05102004A - Formation method of resist pattern - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to obtain a resist pattern forming method capable of obtaining a resist pattern having a short reduction exposure time and high resolution. [Structure] An i-line resist layer 15 is applied thinner than the g-line resist layer 10 on the g-line resist layer 10 formed on a substrate 4. When the i-ray resist layer 15 is reduced and exposed to a predetermined pattern through the lens 2, the i-ray resist layer 15 is bleached into the predetermined pattern. This i-ray resist layer 15
The g-line resist layer 10 is patterned by exposing the entire surface of the g-line using the mask as a mask and then developing. [Effect] Since the predetermined pattern is reduced and exposed on the thin i-line resist layer 15, the time for the reduction exposure is reduced, the throughput is improved, and the i-line resist layer 15 that is in close contact is reduced.
Since the resist pattern of is used as a mask, a resist pattern with high resolution can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist pattern forming method in photolithography used in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art FIG. 4 is a diagram for explaining a conventional resist pattern forming method. When the reticle 1 is irradiated with the exposure light, the pattern formed on the reticle 1 is reduced through the lens 2 and is irradiated on the resist layer 3 formed on the substrate 4 (FIG. 4A). Then, upon development, a resist pattern 3a is formed (FIG. 4B).

[0003]

Since the conventional resist pattern forming method is performed through the above steps, when the resist 3 is subjected to reduction exposure of the pattern formed on the reticle 1, the film thickness of the resist 3 is reduced. Since it is thick, it takes time to expose the pattern, and the throughput decreases.
Further, if the depth of focus is increased in order to completely expose the resist 3, the resolution is lowered. On the other hand, in order to increase the resolution, it is necessary to make the depth of focus shallow, which causes a problem that the resist 3 cannot be completely exposed.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a resist pattern forming method capable of reducing the reduction exposure time and forming a resist pattern having a high resolution. And

[0005]

A resist pattern forming method according to the present invention comprises a step of forming a first resist layer on an underlayer, and a second step having a photobleaching property on the first resist layer. Forming a resist layer thinner than the first resist layer; exposing the second resist layer to a predetermined pattern by reduction exposure, and bleaching the second resist layer to the predetermined pattern; and the predetermined pattern. Using the second resist layer bleached as a mask,
And a step of transferring the predetermined pattern to the first resist layer by exposing the entire surface.

[0006]

In the present invention, since the second resist layer having photobleaching property is formed on the first resist layer to be thinner than the first resist layer, the second resist layer is subjected to reduction exposure of a predetermined pattern, When the second resist layer is bleached into a predetermined pattern, the second resist layer is exposed faster. Further, since the step of transferring the predetermined pattern to the first resist layer by bleaching to the predetermined pattern and using the second resist layer formed on the first resist layer as a mask is provided, the predetermined pattern is formed. It is accurately transferred to the first resist layer.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining a first embodiment of a resist pattern forming method according to the present invention. A negative type g-line resist layer 10 is formed on the substrate 4. An i-line resist layer 15 that is sensitive to the i-line containing a dye, i.e., an i-line resist layer 15 having photobleaching property, is applied to it thinner than the g-line resist layer 10. Then, as shown in FIG. 1 (a), the i-line is exposed by an i-line reduction exposure device (not shown).
The pattern formed on the reticle 1 is reduced by the lens 2 and the i-line resist 15 is reduced and exposed. The dye in the portion of the i-ray resist layer 15 irradiated with the i-ray is bleached, and a reduced pattern of the pattern formed on the reticle 1 is formed in the i-ray resist layer 15.

Thereafter, as shown in FIG. 1 (b), the g-line 6 is exposed to the i-line resist layer 15 by a g-line entire surface exposure device (not shown).
Irradiate the entire surface of. At this time, the g-line 6 is transmitted only to the bleached part of the i-line resist layer 15.
Since the i-line resist layer 15 is in close contact with the g-line resist layer 10, the pattern transferred to the i-line resist layer 15 is transferred to the g-line resist layer 15 with high resolution accuracy.

Next, the unbleached i-line resist layer 15 and the unexposed g-line resist layer 10 are developed with an etching solution for etching to form a resist pattern as shown in FIG. 1 (c). To do. Since the film thickness of the i-line resist layer 15 subjected to reduction exposure is thin, the reduction exposure time is shortened and the throughput is improved. There is an advantage that the i-line resist layer 15 is completely exposed even if the depth of focus is made shallow in order to increase the resolution of the resist pattern of the i-line resist layer 15 during the reduction exposure. Since the g-line resist layer 10 is entirely exposed by using the resist pattern of the i-line resist layer 15 which has been completely exposed as a mask, the resolution of the g-line resist layer 10 becomes high.

FIG. 2 is a diagram showing a second embodiment of the present invention. Similar to the first embodiment, a negative type g-line resist layer 10 is formed on the substrate 4, and the i-line resist layer 15 is applied thereon to be thinner than the g-line resist layer 10. Then, as shown in FIG. 2A, the reduced pattern of the pattern formed on the reticle 1 is transferred to the i-line resist layer 15 by irradiating the i-line by the i-line reduction exposure device, and the i-line resist layer 15 is exposed. Bleach in a predetermined pattern. Then, as shown in FIG. 2B, the entire surface of the i-line resist layer 15 is irradiated with DUV rays 7. Thereafter, as shown in FIGS. 2C and 2D, a resist pattern is formed by the same steps as in the first embodiment.

In this embodiment, the i-ray resist layer 15 is bleached into a predetermined pattern and then the entire surface of the i-ray resist layer 15 is irradiated with the DUV rays 7, so that the i-ray resist layer 15 is hardened and hard. A resist pattern of the i-line resist layer 15 can be formed. Therefore, when the entire surface of the g-ray resist layer 10 is exposed by using the resist pattern as a mask, it is possible to transfer the pattern with higher accuracy than that in the above-described embodiment.

FIG. 3 is a diagram showing a third embodiment. Board 4
A positive type g-ray resist layer 10 is formed on top of which i
The line resist layer 15 is applied thinner than the g-line resist layer 10. Then, as shown in FIG. 3A, the i-line reduction exposure device irradiates the i-line to transfer the reduced pattern of the pattern formed on the reticle 1 to the i-line resist layer 15, and the i-line resist layer 15 is predetermined. Bleach the pattern. After that, development is performed to pattern the i-line resist layer 15 into a predetermined pattern as shown in FIG.

Next, the DUV rays 7 are patterned i
The entire surface of the linear resist layer 15 is irradiated (FIG. 3 (c)). Then, the g-line 6 is irradiated onto the g-line resist layer 10 using the patterned i-line resist layer 15 as a mask (FIG. 3 (d)).
), And then develop to form a resist pattern. Also in this embodiment, the same effect as in the first and second embodiments can be obtained.

[0014]

As described above, according to the present invention, since the second resist layer having photobleaching property is formed thinner than the first resist layer on the first resist layer, the second resist layer is formed. When the predetermined pattern is subjected to reduction exposure and the second resist layer is bleached into the predetermined pattern, the second resist layer is exposed faster. Further, since the step of transferring the predetermined pattern to the first resist layer by bleaching to the predetermined pattern and using the second resist layer formed on the first resist layer as a mask is provided, the predetermined pattern is formed. It is accurately transferred to the first resist layer. As a result, the reduction exposure time is shortened, throughput is improved, and a resist pattern with high resolution can be formed.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a first embodiment of a resist pattern forming method according to the present invention.

FIG. 2 is a diagram for explaining a second embodiment of the resist pattern forming method according to the present invention.

FIG. 3 is a drawing for explaining a third embodiment of the resist pattern forming method according to the present invention.

FIG. 4 is a diagram for explaining a conventional resist pattern forming method.

[Explanation of symbols]

 1 reticle 2 lens 4 substrate 6 g line 10 g line resist layer 15 i line resist layer

[Procedure amendment]

[Submission date] April 2, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

[0003]

Since the conventional resist pattern forming method is performed through the above steps, when the resist 3 is subjected to reduction exposure of the pattern formed on the reticle 1, the film thickness of the resist 3 is reduced. Since it is thick, it takes time to expose the pattern, and the throughput decreases.
Further, if the lens NA is lowered to deepen the depth of focus in order to completely expose the resist 3, the resolution is lowered. On the other hand, if the lens NA is increased to increase the resolution, the depth of focus becomes shallow . This causes a problem that the resist 3 cannot be completely exposed.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 7352-4M H01L 21/30 361 S

Claims (1)

[Claims] 1. A step of forming a first resist layer on an underlayer, and a step of forming a second resist layer having a photobleaching property thinner than the first resist layer on the first resist layer. And a step of subjecting the second resist layer to a reduction exposure of a predetermined pattern and bleaching the second resist layer to the predetermined pattern; and using the second resist layer bleached to the predetermined pattern as a mask. And a step of transferring the predetermined pattern to the first resist layer by whole surface exposure.