JP3348332B2 - Lithography method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lithography method, and more particularly, to a lithography method performed in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, for example, FIG.
The lithography is performed according to the following procedure as shown in the process flow chart of FIG. First, in a first step S51, pattern exposure using an electron beam as exposure light is performed on a resist film formed on a wafer. Next, in a second step S52,
The antistatic upper layer film that has covered the resist film is stripped and removed by a stripping solution. In the next third step S53, post-exposure baking (hereinafter, referred to as PEB) of the resist film is performed using a baking apparatus. Thereafter, in a fourth step S54, heat removal (hereinafter, referred to as cooling) of the wafer and the resist film heated by the PEB is performed. Thereafter, in a fifth step S5, the resist film is developed using a developer, and then a drying step by heating (not shown) and a cooling step subsequent thereto are performed, and the lithography step is completed. Through the lithography process as described above, a resist pattern composed of a resist film is formed on the wafer.

[0003]

However, in the lithography method described above, the PEB process using a baking device is performed between the peeling-off of the upper layer film and the developing process of the resist film. And the TAT of semiconductor device manufacture. The same applies to the case where a multi-developer system is constructed by combining a plurality of exposure apparatuses with one developer in the future.

[0004]

Therefore, in the lithography method of the present invention, after performing pattern exposure, an upper layer film on the resist film is peeled off with a heated peeling solution and post-exposure bake of the resist film is performed. Performing or performing PEB of the resist film with a heated solution is a means for solving the above problem. In the lithography process, the PEB of the resist film is performed with a heated stripping solution or solution, thereby omitting ordinary PEB, removing the upper layer film, and removing the PEB.
To the developing process are continuously performed.

[0005]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a process flow chart showing a lithography method according to claims 1 and 2 of the present invention. First, a first embodiment will be described with reference to FIG. 1, FIG. 2 and FIG.

First, in a first step S11 shown in FIG. 1, pattern exposure is performed on a resist film formed on a wafer. The resist film is made of a chemically amplified resist material containing, for example, a polymethyl methacrylate-based resin as shown in FIG. 2 (1) and a photoacid generator as shown in FIG. 2 (2). Formed on the wafer by the spin coating method. The resist material is not limited to the above, as long as it has good reactivity like the above-mentioned resist material. For example, a poly-hydroxystyrene (PHS) -based material can be used.

On this resist film, an upper layer film corresponding to the exposure light used for pattern exposure is formed.
For example, when a resist material comprising the photosensitive composition is used, if the exposure light is an electron beam, an upper layer film made of an antistatic agent is formed on the resist film, and the exposure light is ArF (argon). In the case of (fluorine) excimer laser light, an upper layer film made of an antireflection film is formed on the resist film. Here, for example, the upper layer film is formed of a water-soluble material. Then, the pattern exposure is performed on the resist film from above the upper layer film by using an electron beam or ArF (argon fluorine) excimer laser light as exposure light. Note that, as the exposure light, light other than the above-described exposure light may be used depending on the resist material constituting the resist film.

Next, in a second step S12 shown in FIG. 1, the removal of the upper layer film and the post-exposure baking (hereinafter referred to as P
EB) at the same time. Here, for example, the second step S12 is performed as follows using the spin developer 3 shown in FIG. First, as shown in FIG. 3A, the wafer 1 is placed on the rotating sample stage 31 of the spin devarper 3 with the surface on which the resist film subjected to the pattern exposure is formed facing upward. Then, the wafer 10 is fixed to the rotating sample table 31 by suction. Next, as shown in FIG.
The heated stripper 20 is supplied into the cup 32 of the spin developer 3. At this time, pure water is used as the stripping liquid 20 because the upper layer film is water-soluble. When the resist material shown in FIG. 2 is used, the resist film and the upper layer film are immersed in a stripping solution 20 (pure water) heated to about 70 ° C. to 90 ° C. To

Then, as shown in FIG. 3 (3), the wafer 10 is stripped until the upper layer film is stripped and removed by the heated stripping solution 20 and the resist film is sufficiently PEBed by the stripping solution. 20 and peeling and removing the upper layer film and PEB of the resist film are performed in the same step.

Thereafter, as shown in FIG. 3D, the stripper 20 is drained from the cup 32, and pure water is supplied into the cup 32 to clean the surface of the wafer 10 and remove heat. Here, pure water having the same temperature as the developing temperature in the next development processing step, for example, pure water at room temperature of about 20 ° C. to 30 ° C. is used. Next, as shown in FIG.
Is rotated to rotate and dry the wafer 10. As described above, the peeling and removal of the upper layer film and the PEB of the resist film shown in the second step S12 in FIG. 1 are performed in the same step.

Next, in a third step S13 of FIG. 1, subsequent to the second step S12, the resist film is developed using the spin developer 3 shown in FIG. 3 to form a resist pattern on the surface of the wafer. Form. As described above, after the peeling and removal of the upper layer film, the PEB of the resist film, and the development process of the resist film are continuously performed using the same spin developer, the wafer is heated and dried using a hot plate. . Next, the wafer is stored in a carrier station, and the lithography process is completed.

FIG. 4 is a process flow chart showing a lithography method according to claims 3 and 4 of the present invention. The second embodiment will be described below with reference to FIG. First, in a first step S41 in FIG. 4, pattern exposure is performed on a resist film formed on a wafer. The resist film is made of, for example, a resist material having good reactivity and has an upper surface covered with an upper layer film, as described in the first embodiment. The pattern exposure of the resist film is performed in the same manner as in the first embodiment.

Next, in a second step S42 in FIG. 4, the upper layer film is peeled and removed using pure water as a peeling solution. In this step, the upper layer film is stripped by continuously supplying the stripper 20 at room temperature to the surface of the wafer 10 using, for example, the spin developer 3 shown in FIG.

Next, in a third step S43 of FIG. 4, PEB of the resist film is performed using the heated solution. This step is performed using the spin developer 3 shown in FIG. 3, for example, following the second step (S42). Then, for example, pure water is used for the solution 50, and the wafer 10 is immersed in the solution 50 in the same manner as in the second step (S12) of the first embodiment. Thus, for example, PEB of the resist film is performed in a state where the influence of the acid or fluorine in the upper layer film on the resist film is prevented and the stability of the process is ensured. Thereafter, for example, normal temperature pure water 40 is supplied to the wafer 10 to remove heat, and then the wafer 10 is spin-dried.

The solution 50 is not limited to pure water, but may be a liquid that can be heated to a temperature sufficient for PEB of the resist film. If the solution 50 does not dissolve the upper film, the second step S42 and the third step S43 in FIG.
May be performed in the reverse order.

Next, in a fourth step S44, similarly to the third step (S13) of the first embodiment, the resist film is developed using a spin developer to form a resist pattern on the surface of the wafer. . Thereafter, heat drying using a hot plate is performed, and then the wafer is stored in the carrier station, and the lithography process is completed.

[0017]

As described above, according to the lithography method of the present invention, the removal of the upper layer film on the resist film and the PEB of the resist film are carried out in the same step by using a heated remover or by heating. Performing PEB using the prepared solution removes the upper layer film and removes the PEB of the resist film.
The process from to the development process of the resist film is a normal P
The EB step can be omitted and the steps can be performed continuously within the same developer. Therefore, the number of lithography steps can be reduced, and the throughput can be increased and the TAT can be improved.

[Brief description of the drawings]

FIG. 1 is a process flowchart of a lithography method according to a first embodiment.

FIG. 2 is a diagram showing components of a resist film used in a lithography method.

FIG. 3 is a diagram illustrating a process using a stripping solution.

FIG. 4 is a process flowchart of a lithography method according to a second embodiment.

FIG. 5 is a process flowchart of a conventional lithography method.

[Explanation of symbols]

 20 stripper 50 solution

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁷ Identification code FI H01L 21/30 569F 571

Claims (2)

(57) [Claims] 1. A first step of performing pattern exposure on a resist film having a surface covered with an upper layer film, and removing and removing the upper layer film from above the resist film with a heated stripper. A lithography method, comprising: performing a second step of performing post-exposure baking of a film; and a third step of performing a development process of the resist film. 2. The lithography method according to claim 1, wherein the resist film is a polymethyl methacrylate-based chemically amplified resist.