JPS611018A - Forming method of fine pattern - Google Patents

Abstract

PURPOSE:To accurately form a fine pattern by measuring the size of an image by an electron beam scanning of low energy of the pattern formed by charged particle beam of a film to be treated on a substrate, and controlling the beam emitting amount in response to the result. CONSTITUTION:An electron beam 2 is emitted to a resist film 60 to form a fine pattern, the emitted part 60a is scanned by an electron beam 12 of low energy and low current, reflected electrons 14 are detected by a detector 15, and an enlarged image of the part 6a is indicated on an indicator 16. The size of the pattern is measured from the enlarged image, and the exposure amount of the beam 2 is controlled in response to the result. Accordingly, the pattern can be accurately formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for forming a fine pattern on a film to be processed provided on the main surface of a substrate such as a semiconductor wafer by irradiation with a charged particle beam.

[Prior art]

Hereinafter, a method for forming a finely patterned resist film on the main surface of a semiconductor wafer will be described as an example.

Figure 1 (4) is a cross-sectional view showing the main components of an example of a fine pattern forming apparatus used in the conventional method of forming a resist film with a fine pattern on the main surface of a semiconductor wafer, and Figure 1 (B) is FIG. 2 is a cross-sectional view showing a resist film formed on the main surface of a semiconductor wafer by this conventional apparatus.

In the figure, (1) exposes a negative resist film (60) for electron beam exposure formed on the main surface of a lead semiconductor wafer in a vacuum chamber (not shown) of a fine pattern forming apparatus. an electron gun that emits an electron beam (2) with the required energy for

(3) is an electromagnetic lens that focuses and deflects the electron beam (2).

In a conventional method using such a fine pattern forming apparatus, first, as shown in FIG. 1(A), the main surface of a semiconductor wafer (A) is The resist film (6
The electron beam (2) emitted from the electron gun (1) and having the required energy is focused and deflected by the action of the electromagnetic lens (3) and irradiated only on the part (60a) where the fine pattern (0) is to be formed. Expose.

Next, as shown in FIG. 1B, the exposed resist film (6o) is formed on the main surface and the semiconductor wafer ω is taken out from the vacuum chamber, and the exposed resist film (6o) is removed from the vacuum chamber. (60) was developed and the resist film (
When the unexposed portion of 60) is removed, a semiconductor wafer is obtained in which a portion (60a) of a finely patterned resist film (60) is formed on the main surface.

By the way, in this conventional method, the pattern dimensions of the portion (60a) of the resist film (60) change depending on the amount of exposure of the electron beam (2) to the portion (60a) of the resist film (60). (60) part (60
In order to accurately form the pattern dimensions of a), measure the entire pattern dimensions of the part (60a) of the resist film (60), and use the measurement results to determine the part (6o) of the resist film (6o) of the electron beam (2). It was necessary to control the amount of exposure to 60a). But Regis)! (60)
When measuring the pattern dimensions of the portion (60a).

Electron beam (2) is applied to the portion (60a) of the resist film (60)
) is taken out of the vacuum chamber of the micropattern forming device and developed, and then the portion (60a) of the resist film (60) is measured using another micropattern size measuring device. Since the pattern dimensions must be measured, the portion (60a) of the resist film (60) of the electron beam (2) is determined based on the measurement results.
It is difficult to control the amount of exposure to the resist film (60), and it is not easy to accurately form the pattern dimensions of the portion (60a) of the resist film (60). [Summary of the Invention] This invention solves these drawbacks. This is a low-energy, low-current method that does not cause any change in the fine pattern formed by irradiating the film to be processed with a charged particle beam on the main surface of the substrate. By measuring the dimensions of the fine pattern using an image of the fine pattern created by reflected electrons generated by irradiating the electron beam, and controlling the amount of charged particle beam irradiation to the film to be processed based on the measurement results, the fine pattern on the film to be processed is created. The purpose of this invention is to provide a method that can form a structure with high precision.

[Embodiments of the invention]

FIG. 2 is a sectional view showing the main components of a fine pattern forming apparatus used in an embodiment of the method of the present invention for forming a resist film with a fine pattern on the main surface of a semiconductor wafer.

In the figure, the same symbols as those shown in FIG. 1 indicate equivalent parts.The electron beam (2) is the charged particle beam 1 in this embodiment, and the resist film (60) is the covered It is a treated membrane.

θη is the electron beam (2) that irradiates the portion (60a) of the resist film (60) exposed by the electron beam (2);
This electron beam @ emits resist film (
The energy and current are set to be low so as not to change the part 60) (60a). α 葎 is an electromagnetic lens that focuses and deflects the electron beam @, α→ is a reflected electron generated by irradiating the resist film (60) part (60a) with the electron beam (2), and <lie is an electromagnetic lens that focuses and deflects the electron beam @. The detector to detect, a6, is the electromagnetic lens α and the detector (
141 and resist film (6) of the electron beam (2).
This is a display device that displays an enlarged image of the portion (60a) obtained by detecting reflected electrons 04) generated by irradiating the portion (60a) of 0) with a detector Q5.

In the method of this embodiment using the fine pattern forming apparatus configured as described above, the electron beam (c) is applied to the resist film (6) in the vacuum chamber of the fine pattern forming apparatus.
0) exposed by the electron beam (2) (60a
) can be scanned without changing the part (60) of the resist film (60) of the electron beam (6).
A reflected electron a41 generated when scanning 0a) is detected by a detector αQK. I can do it. Therefore, the part (60a) of the resist film (6o) displayed on the 1 display device OQ
) shows the portion (60a) of the resist film (60).
), and based on the measurement results, the portion (60a) of the resist film (60) of the electron beam (2) is measured.
Since the amount of exposure to the resist film (60) can be controlled, the pattern dimensions of the portion (60a) of the resist film (60) can be formed with high precision.

In this embodiment, a method of exposing a resist film (60) provided on the main surface of a semiconductor wafer (toward) with an electron beam (2) is described as an example, but the present invention is not limited to this. Methods of exposing resist films for ion beam exposure provided on the main surfaces of other substrates such as wafers and glass substrates with ion beams, and methods of exposing insulating or conductive films provided on the main surfaces of these substrates. It can also be applied to a method of etching using an ion beam.

〔Effect of the invention〕

As explained above, in the method for forming a fine pattern according to the present invention, a fine pattern formed by irradiating a film to be processed on the main surface of a substrate with a charged particle beam uses a low energy that does not change the film to be processed. , the dimensions of the fine pattern are measured using the image of the fine pattern created by reflected electrons generated by irradiation with a low-current electron beam, and the amount of irradiation of the charged particle beam to the film to be processed is controlled based on the measurement results. It is possible to form fine patterns with high precision.

[Brief explanation of the drawing]

FIG. 1(A) is a cross-sectional view showing the main components of an example of a fine pattern forming apparatus used in the conventional method of forming a resist film with a fine pattern on the main surface of a semiconductor wafer, and FIG. 1(B) is A cross-sectional view showing a resist film formed on the main surface of a semiconductor wafer by this conventional apparatus, and FIG. 2 is a method according to an embodiment of the present invention for forming a resist film with a fine pattern on the main surface of a semiconductor wafer. 1 is a cross-sectional view showing the main components of a fine pattern forming apparatus used for. In the figure, (2) is an electron beam (charged particle beam). (a) is the electron beam, α→ is the reflected electron of the electron beam (6). OQ is a display device that displays images of fine patterns by reflected electrons (2), (to) is a semiconductor wafer, and (60) is a resist film (film to be processed). Note that the same reference numerals in Figure 5 indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A step of irradiating a charged particle beam only to a portion of a film to be processed on the main surface of a substrate where a fine pattern is to be formed; A step of measuring the dimensions of the fine pattern using an image of the fine pattern using reflected electrons generated by irradiating the fine pattern with a low-energy, low-current electron beam that does not cause any change in the film to be processed; A method for forming a fine pattern, comprising the step of controlling the amount of irradiation of the charged particle beam to the film to be processed based on the dimension value of the fine pattern. (2) The method for forming a fine pattern according to claim 1, wherein the film to be processed is a resist film that is sensitive to irradiation with a charged particle beam.