JPH0562945A - Method of forming resist pattern - Google Patents

Abstract

PURPOSE:To make it possible to use again a film to be processed in the case the film to be processed does not pass a developing inspection in a resist silytating process. CONSTITUTION:In a method of forming by patterning a resist on a film 1 to be processed by a resist silytating process, 10 to 80% of the silytated resist 2 on the film 1 to be processed is removed by dry etching and at the point of time, a developing inspection of the resist is made and in the case the resist passes the inspection, a residual resist is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a resist pattern, and more particularly to a method for processing a resist film using dry etching.

[0002]

2. Description of the Related Art When patterning a film to be processed using a resist, a resist silylation process is used for complicated patterning due to the problem of the etching selectivity between the resist and the film to be processed. The outline of this conventional method is as follows. First, as shown in FIG. 7, a silylation resist 12 is applied onto the film 11 to be processed formed on the device wafer 11 'and irradiated with ultraviolet rays 12' having a predetermined pattern. Next, a silylating agent 14 such as HMDS (hexamethyldisilazane) is diffused into the film to be processed, and the portion irradiated with ultraviolet rays is silylated to form a resist silylated layer 13 (FIG. 8). Next, by dry etching, the portions other than the silylated portion are etched (FIG. 9). Development inspection is performed here. Then, the film 11 that has passed the inspection is etched, and finally the resist film is removed.

[0003]

According to the above method, when a pattern defect is found in the development inspection,
It is also preferable from the viewpoint of cost reduction that the resist having the defective pattern is removed, and the resist silylation is performed again using the same film to be processed such as a wafer. However, when the silylated resist is removed by etching, it is difficult to remove it without damaging the film to be processed. That is, even if the etching selection ratio between the silylated resist and the film to be processed is large, some damage is caused.

[0004]

The present invention has been made under such circumstances, and is characterized in that when a resist pattern is formed on a film to be processed by a resist silylation process, first of all, The silylation resist is applied on the film to be processed, and the irradiated area is silylated after irradiating with ultraviolet light in a predetermined pattern, and then 10% of the resist film thickness
After clarifying the silylated resist layer by performing preliminary dry etching with a thickness of 80% or less, shape inspection of the silylated resist layer is performed, and after the silylated resist layer is not tested, the silylated resist layer is not etched. The point is that the reaction resist is removed by ashing, the above steps are repeated, and the unreacted resist is removed for those that have passed the inspection.

Here, the film to be processed is a film to be processed by etching using a resist, for example, a polysilicon film on a device wafer, an Al metal film, a W-based metal film, a SiO ₂ film, A SiN film or the like. The silylating resist is a resist which is activated by ultraviolet rays and is silylated by diffusion of a silylating agent.

The thickness of the unreacted (non-silylated) resist removed by preliminary dry etching is 10% or more and 80
% Or less, preferably 30% or more and 60% or less. The reason why it is set to 10% or more is that the accuracy of the development inspection is not lower than this, and the reason that it is 80% or less is that the film to be processed may be damaged if it is higher than this.

The etching of the unreacted resist in the present invention may be ordinary dry etching, and no special one is necessary. Silylated part (resist silylated layer)
Any method may be used as long as it is not etched.

The development inspection is an ordinary inspection of line width, alignment accuracy, etc., and does not need to be special. For example, alignment inspection using an optical microscope, SEM
It is a method of line width inspection and the like using. Then, if this development inspection is passed, the dry etching is performed again by the same etching as the above or another method to remove the residual unreacted resist. This dry etching is performed by a method such as O ₂ plasma etching.

When the development inspection is defective, the silylated portion is removed by etching by reactive ion etching. In this case, the film to be processed is usually etched to some extent, but in the method of the present invention, since the unreacted resist remains with a thickness in the range of 20 to 90% of the initial amount to protect the film to be processed, The membrane is not damaged. In other words, the remaining thickness is determined so as to exert the protective effect. Then, if the silylated portion can be removed, the remaining resist is removed from the film by a method that does not damage the film to be processed. This method is preferably ashing using oxygen gas.

As a result, the film to be processed has returned to the state before the resist was applied, and the resist can be applied and patterned again, and the waste of the silicon wafer and the like can be reduced.

[0011]

According to the above manufacturing method, the substrate can be regenerated even if it is defective by the development inspection, and the resist silylation process can be repeatedly used.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail based on the embodiments shown in the drawings. FIG. 1 is a partial cross-sectional view in a process for explaining one embodiment of the manufacturing method of the present invention. First, Al.S is formed as a film to be processed on the device wafer 1 '.
An i film (thickness of 9000Å) 1 was formed by the sputtering method. On top of this, as the silylated resist 2, [PLASM
ASK200G-C (manufactured by Japan Synthetic Rubber Co., Ltd.)] was applied using a spin coater to give a film thickness of 15000 to 25000.
Form at Å (center 20000Å). This resist film was irradiated with ultraviolet rays using a stepper using a Cr mask (FIG. 1). This step may be the same as for a normal negative resist. Next, this substrate was kept in a hexamethyldisilazane atmosphere on a hot plate at about 160 ° C. for 3 to 4 minutes to sililate the above-mentioned exposed region (FIG. 2).

Using the resist silylated layer 3 thus obtained as a mask, the resist film was subjected to dry etching under the following conditions to etch the resist film by 4000 Å (residual film thickness was about 17,000 Å (FIG. 3). : O ₂ plasma generation output: 200 W Pressure: 20 mTorr Time: 30 seconds At this stage, alignment inspection using an optical microscope, S
Line width inspection was performed using EM.

As a result of the development inspection, if the result is acceptable, the remaining unreacted resist 2 is removed by dry etching under the same conditions as above (FIG. 6). This completes the masking of the resist. Following this, ordinary etching of the film to be processed may be performed.

When the development inspection fails, the resist silylated layer 3 is removed by reactive ion etching under the following conditions (FIG. 4). Etching gas: Cl ₂ plasma generation output: 70 W Pressure: 8 mTorr Time: 2 minutes 30 seconds Next, all the unreacted resist 2 was removed with a normal barrel type asher (O ₂ gas) (FIG. 5). In this state, the film to be processed 1 was not damaged and the resist silylation process could be performed again as shown in FIG.

[0016]

As described above, according to the present invention, the development inspection is conducted in the state where the unreacted resist is partially left, and the patterning of the resist is completed after confirming the acceptance. In this case, the film to be processed is protected when the resist silylated layer is removed by reactive etching. As a result, the processed film can be reused.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing one step of the method of the present invention.

FIG. 2 is a partial cross-sectional view showing one step of the method of the present invention.

FIG. 3 is a partial cross-sectional view showing one step of the method of the present invention.

FIG. 4 is a partial cross-sectional view showing a reproducing step.

FIG. 5 is a partial cross-sectional view showing a reproducing step.

FIG. 6 is a partial cross-sectional view showing one step of the method of the present invention.

FIG. 7 is a partial cross-sectional view showing one step of a conventional method.

FIG. 8 is a partial cross-sectional view showing one step of a conventional method.

FIG. 9 is a partial cross-sectional view showing one step of a conventional method.

[Explanation of symbols]

 1 Processed Film 2 Silylation Resist 3 Resist Silylation Layer 4 Silylating Agent

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H01L 21/027

Claims (1)

[Claims] 1. When forming a resist pattern on a film to be processed by a resist silylation process, first, a silylation resist is applied on the film to be processed, and ultraviolet rays are irradiated in a predetermined pattern, and then the irradiation region is silylated, Next, after clarifying the silylated resist layer by performing preliminary dry etching to a thickness of 10% or more and 80% or less of the resist film thickness, a shape inspection of the silylated resist layer is performed, and the silylated resist layer is silylated for those that fail the inspection. After etching the resist layer, the unreacted resist is removed by ashing and the above steps are repeated, and those that have passed the inspection are characterized by removing the unreacted resist by main dry etching. Pattern formation method.