JPH0574676A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a resist pattern which can be realized through a simple process and has an excellent resisting property at the time of working a base layer by forming an electron-beam resist layer on a photoresist layer and exposing and developing the photoresist layer after the electron beam resist layer is exposed to and developed by an electron beam after plotting the pattern. CONSTITUTION:After a photoresist layer 5 which reacts to light is formed on a base layer 1 to be worked, an electron-beam resist layer 6 which is sensitive to an electron beam and blocks light to which the layer 5 is sensitive is formed on the layer 5. Then a pattern corresponding to an electronic beam is plotted on the layer 6 and the layer is exposed to and developed by the electron beam. After developing the layer 6, the photoresist layer 5 is exposed and developed by using the developed resist layer 6A as a mask. In the succeeding process, for example, after the base layer 1 is etched by an RIE method by using the resist patterns 6A and 5A as masks, the patterns are transferred to the layer 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to lithography for forming a pattern in a semiconductor device.

[0002]

2. Description of the Related Art Electron beam resists used in electron beam lithography have not yet been obtained with sufficient sensitivity. Therefore, when a simple one-layer resist similar to that used in normal photolithography is used, there is a problem that the pattern drawing time becomes long. The thinner the resist, the shorter the drawing time, but the resist layer must have a certain thickness to withstand the subsequent etching. In particular, the resist layer used for manufacturing a semiconductor device having an uneven lower layer is required to have a thickness of 1 to 2 μm.

As one method for solving the above problems,
A three layer resist may be used. FIG. 2 is a manufacturing process diagram of a conventional semiconductor device using a three-layer resist.

First, in step (a), a lower resist layer 2 which is not sensitive to ordinary light is formed on a base layer 1 made of a metal layer, an insulating film layer, a silicon substrate or the like to be processed. In the next step (b), the intermediate layer 3 made of a semiconductor oxide film is formed, and in the subsequent step (c), the electron beam resist layer 4 is formed. Then, in step (d), after electron beam drawing and development on the electron beam resist layer, in steps (e) and (f), the lower layer is sequentially etched by changing the etching conditions using the upper layer as a mask. A resist pattern is formed as shown in f). After the step (f), the underlying layer 1 is etched or ions are implanted using the lower resist layer 2 as a mask.

[0005]

However, according to the above manufacturing process, the drawing time can be shortened by making the electron beam resist layer thin, but there is a problem that the process is considerably complicated as compared with the one-layer resist. is there.

An object of the present invention is to provide a method of manufacturing a semiconductor device in which a resist pattern which can be realized by a simple process and which has good resistance when processing an underlayer is formed.

[0007]

In order to solve the above-mentioned problems, the present invention comprises a step of forming a photoresist layer which reacts with light on an underlayer to be processed, and a step of exposing the photoresist to an electron beam. A step of forming an electron beam resist layer on the photoresist layer, the layer blocking light that is sensitive to light;
A step of drawing a pattern corresponding to an electron beam on the electron beam resist layer to expose / develop the electron beam resist layer with an electron beam; and a step of exposing / developing the photoresist layer with the developed electron beam resist layer as a mask The method for manufacturing a semiconductor device includes the steps of:

[0008]

According to the present invention, a photoresist layer which reacts with light is formed on the underlayer to be processed, and the photoresist layer which is exposed to an electron beam and blocks the photoresist layer to be exposed to light is blocked. An electron beam resist layer is formed. When an electron beam resist layer is drawn and exposed by an electron beam, the electron beam resist layer is exposed to the resist pattern by the drawing.
The photoresist layer has been developed, leaving the photoresist layer intact. Next, when the photoresist layer is exposed to light and developed from above, the photoresist layer is masked by the electron beam resist layer which has been previously drawn and developed to form a resist pattern by the drawing.

[0009]

FIG. 1 is a manufacturing process diagram of a semiconductor device showing an embodiment of the present invention.

In the figure, reference numeral 1 designates an underlayer to be processed as in FIG. 2, and in this case, it is made of, for example, an aluminum film.

Numeral 5 is a so-called photoresist layer which is exposed to a specific light (g-line which will be described later).
For example, apply TSMR8700 manufactured by Tokyo Ohka Kogyo Co., Ltd.
It is baked at 0 ° C. for 40 seconds to have a thickness of about 1.4 μm.

Reference numeral 6 is an electron beam resist layer, which is g of a mercury lamp.
A dye such as Tinubin manufactured by Ciba-Geigy Co. is mixed so as to be opaque to the line (wavelength 436 nm). The electron beam resist layer is applied on the photoresist layer 5 in step (b) and baked at 90 ° C. for 5 minutes to have a thickness of about 0.6 μm.

Then, in the step (c), the electron beam resist layer 6 is exposed by an electron beam of 30 KV and 4 μC / cm ² by drawing an image corresponding to the electron beam, and then exposed to 100 with an alkaline developer.
It is developed for 2 seconds. As a result, a resist pattern 6A is formed by the drawing as shown in step (c). At this time, the photoresist layer 5 is not exposed to light.

In the subsequent steps (d) and (e), exposure is carried out for 0.2 seconds from above using the g-line of a mercury lamp and development is carried out with an alkali developing solution for photoresist. As a result, a resist pattern 5A is formed using the resist pattern 6A as a mask.

In the subsequent steps, the resist pattern
The underlying layer 1 is, for example, RIE
Then, the pattern is transferred to the underlayer 1.

In this embodiment, since the pattern is formed by the two-layer resist, the process is simplified as compared with the conventional three-layer resist.

Further, the etching of the intermediate layer and the etching of the lower layer resist, which are required for the conventional three-layer resist, are unnecessary, and light irradiation and development can be performed under the conventional manufacturing conditions using the conventional photolithography apparatus. No additional equipment or steps required.

Further, since the formed photoresist layer 5 is a resist for ordinary photolithography, the subsequent etching conditions can be the same as in the case of the conventional one-layer resist, and in the case of the three-layer resist. As described above, it is not necessary to change the etching conditions due to the fact that the resist material used as the etching mask is different from that of the conventional photoresist.

In step (e) of FIG. 1, the electron beam resist layer 6 remains after the development of the photoresist 5. However, the electron beam resist layer 6 may be wholly or partially exposed depending on the material of both resists and the developing method. Is removed, but it does not in any way go against the spirit of the present invention.

[0020]

As described above, according to the present invention, a photoresist layer and an electron beam resist layer for preventing exposure to the photoresist layer are sequentially formed on the underlying layer to be processed, Since the pattern is drawn on the electron beam resist layer, exposed and developed by the electron beam, and the photoresist layer is exposed and developed using this as a mask, the double drawing by the electron beam resist layer and the photoresist layer is performed by common drawing. Resist pattern is formed, and these functions as a tough mask for subsequent etching of the underlying layer.
Since the resist pattern is formed by the two-layer resist, it can be realized by a simple process as compared with the conventional three-layer resist.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a semiconductor device showing an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of a semiconductor device showing a conventional example.

[Explanation of symbols]

1 ... Underlayer, 5 ... Photoresist layer, 6 ... Electron beam resist layer, 5A, 6A ... Resist pattern.

Front page continued (72) Inventor Akihiro Yokoyama 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Zero Tsukus Co., Ltd.Ebina Business Office (72) Inventor Yasushi Sakata 2274 Hongo, Ebina City, Kanagawa Prefecture Ebina Business Office Fuji Zero Tsuxu Co., Ltd.

Claims (1)

[Claims] 1. A step of forming a photoresist layer which is sensitive to light on an underlayer to be processed, and an electron beam resist layer which is exposed to an electron beam and blocks light which can be exposed to the photoresist layer. Forming on the electron beam resist layer, drawing on the electron beam resist layer corresponding to an electron beam, exposing and developing the electron beam resist layer with the electron beam, and masking the electron beam resist layer after development. And a step of exposing and developing the photoresist layer as described above.