JPS6010624A - Forming method for pattern - Google Patents

Abstract

PURPOSE:To accurately obtain an ultrafine pattern in a short time by locally strengthening the exposure strength in the exposure of a resist of a substrate, thereby inverting a negative or a positive. CONSTITUTION:A thin primary film 2 such as an oxidized film is formed on a substrate 1, and a resist film 3 is coated thereon. Then, an electron beam is emitted as an arrow P, only a desired pattern is then strengthened in the exposure strength, and the electron beam is emitted as an arrow Q. The portion that the strength is locally enhanced by the beam in the film 3 and exposed is used as a portion of an ROM of a mask ROM or a portion of the ultrafine pattern, master slice or a mark for direct exposure. With a resist pattern 6 obtained in this manner as a mask the film 2 is etched. Thereafter, the pattern 6 is exfoliated, removed, and a desired pattern 7 can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming fine patterns on a resist film subjected to VC on a thin film surface of a substrate for manufacturing semiconductor devices and the like.

When manufacturing semiconductor devices and the like, it is necessary to form extremely fine patterns at predetermined positions with high precision, and these patterns are generally formed by photolithography technology.

A conventional pattern forming method will be explained with reference to FIGS. 1(A) to 1(D).

In this figure, reference numeral 1 denotes a substrate made of a semiconductor wafer or the like, on which a base thin film 2 such as an oxide film is applied. 3 is a resist film applied to the two surfaces of the base thin film. From the top of the substrate 1 formed in this way, FIG.
As shown, an electron beam is irradiated from above in the direction of arrow P. Next, it is developed with a predetermined developer to obtain a resist pattern 4 as shown in FIG. 1(B). Using this resist pattern 41 as a mask, the underlying thin film 2 is etched, as shown in FIG.
Pattern 5 is formed as shown in C). Then, by peeling off and removing the resist pattern 4, the pattern shown in FIG. 1CD)
A desired pattern 5 such as the following can be obtained on the substrate 1.

In the conventional pattern forming method described above, the pattern l is locally
If you wanted to reverse the negative and positive, you had to create the drafting data yourself each time. Furthermore, when it is desired to obtain a pattern such as a mask ROM or a master slice, it is necessary to create drawing data each time. Alternatively, when forming ultraviolet mask dandruff, it is necessary to create a mask each time as described above. For this reason, it is necessary to create the drafting data itself and to create the ultraviolet mask 1, resulting in a long construction period and high costs. Furthermore, in the case of fine patterns, it is extremely difficult to create them using a photomask, and there are disadvantages in that a sharp pattern cannot be obtained.

This invention was made in order to eliminate the drawbacks of the conventional pattern forming method described above, and by increasing the exposure intensity locally during exposure of the resist on the substrate, the negative and positive are reversed and a fine pattern is formed in a short period of time. It is an object of the present invention to provide a method for forming a pattern that can be obtained with high accuracy.One embodiment of the present invention will be described below with reference to FIGS. 2(A) to 2(E)K.

First, as shown in FIG. 2(A)K, two base thin films such as an oxide film are applied to the upper surface of the substrate 1 made of a semiconductor wafer.
On top of that, a resist film 3, for example, a conductive organic charge transfer complex TCNQ (Latracy 7 no P-ginodimethane) is applied at a rate of about 50%
Apply to the thickness of Fl OA. Thereafter, an electron beam is irradiated from above the substrate 1 in the direction of arrow P. The irradiation amount at this time is 6 x 1O-6C/cm2. Next, the second
As shown in Figure (B) K1. Only the desired pattern is exposed with high exposure intensity (1) and the electron beam is irradiated as shown by arrow Q.The irradiation amount at this time is 6 x 10' C/cm2.After the exposure is completed, develop with a predetermined 0 developer and 1 developer.・!l/7.L drying plate 6・After development, the “゛j pattern” is shown in Figure 2 (C)K.

With normal exposure, this resist is (10'C7cm"
) Cutting occurs and the polymer becomes a monomer, exhibiting the characteristics of a positive resist, but when the exposure intensity becomes strong (10' C/
/cm2 or more), local heat increases due to the high energy of the electron beam, crosslinks occur, and the resist is reversed to a negative resist. After development, only the exposed areas can be obtained as a negative film, and the normally exposed areas can be dissolved and removed.

The portions of the resist film 3 to which the electron beam is locally exposed by increasing the intensity are a ROM portion of a mask ROM, a fine pattern, a master slice, or a mark for direct exposure. Using the six resist pattern masks thus obtained, the underlying thin film 2 is etched as shown in FIG. 2(D)K. Thereafter, the resist pattern 6 is peeled off to obtain a desired pattern 7 as shown in FIG. 2(E). Pattern 7, which could not be obtained using 5KL, had very sharp pattern breaks.

In the conventional pattern forming method using only the uniform wr source described above, it was necessary to create drawing data for all types and all processes, and it was also necessary to create a half-odd mask, but the method of the present invention According to the method, a pattern can be formed in a specific part by changing the intensity of electron beam exposure, so complicated and troublesome drawing data is unnecessary, and if applied to direct exposure of a wafer, the number of photomasks can be reduced. This shortens the construction period and improves productivity. Moreover, the pattern that cannot be obtained is sharp and accurate.

In the above embodiment, the case of an electron beam has been described, but the same effect can be obtained by using ultraviolet rays, deep ultraviolet rays, X-rays, etc., which take advantage of the characteristic that negative and positive are reversed by changes in intensity. In addition, as for the resist, although we have described the case of TCNQ, there is a novolac resist (AZ-1350) whose negative/positive state is reversed depending on the change in irradiation dose, or EBR=
9' (manufactured by Toton Co., Ltd.) may also be used, and the same effect can be achieved.

Further, in the above embodiment, the oxide film is used as the base thin film 2 of the substrate 1, but other thin films may be used, and the substrate 1 may be made of quartz, glass, etc. (similar effects can be obtained. In the above embodiment, the exposure to increase the exposure intensity was performed later, but it may be performed earlier and the same effect will be obtained.

The method of locally increasing the exposure intensity may be in a part of the chip, or only in a predetermined chip in the mask, or
σ in the mask] Only a predetermined portion σJ may be used.

In the method of forming a pattern by exposing a wafer substrate to an electron beam (11), a positive resist (Y) is often used, making it difficult to detect marks, but with the method of this invention, it is possible to As a result, a negative pattern cannot be obtained, making mark detection easier.

As explained above, in this invention, a negative-positive reversal pattern can be obtained by partially increasing the exposure intensity of the resist on the substrate, so the construction period is short, the cost is low, and fine patterns can be obtained with high precision. It has the advantage of being

[Brief explanation of drawings]

FIGS. 1(A) to (D) are cross-sectional views showing the steps of a conventional pattern forming method, and FIGS. 2(A) to (E) are cross-sectional views showing the steps of a pattern forming method according to an embodiment of the present invention. It is. In the figure, 1 is a substrate, 2 is a base thin film, 3 is a resist film, 6 is a resist pattern, and 7 is a pattern. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Masuo Oiwa (2 others) Figure 1 Figure 2 Procedural amendment (voluntary) 1. Display of the case: Japanese Patent Application No. 13-119F (No. 13 No. 2, title of the invention: Pattern forming method 3, representative person making the amendment: Hitoshi Katayama, section 5, detailed description of the invention in the specification to be amended, column 6, amendment Contents (1) "Drawing data" in lines 8 to 9 on page 3 of the specification and '14h are corrected to "drafting data". (2) Similarly, "(latrasiano" on page 4, line 10) is corrected as "drafting data".
[Correct it to (tetracyano-). (3) Similarly, on page 6, lines 16-17, "(manufactured by Toshisha Co., Ltd.) may be used," is corrected to "(manufactured by Toshisha Co., Ltd.) etc. may be used." Please call

Claims (7)

[Claims] (1) A pattern forming method in which a pattern is formed by irradiating a resist applied on a substrate with radiation, which is characterized in that exposure is performed by locally changing the intensity of the radiation. (2) The pattern forming method according to claim (1), wherein the radiation is ultraviolet rays. (3) The pattern forming method according to claim (1), wherein the radiation is far ultraviolet rays. (4) The pattern forming method according to claim (1), wherein the radiation is an electron beam. (5) The pattern forming method according to claim (1), wherein the radiation is Xm. (6) The pattern forming method according to claim (1), wherein the resist is a resist that has a property of reversing negative and positive depending on the intensity of radiation. (7) The pattern forming method according to claim σ), item (1), characterized in that the change in radiation intensity is carried out at least within the chip and within the mask.