JPS60154526A - Pattern forming process - Google Patents

Abstract

PURPOSE:To produce organic high molecular film patterns efficiently by a method wherein an organic high molecular film, an oxide film, a halogenated silver emulsion film are exposed for development on an Si substrate to be successively etched utilizing silver patterns as masks. CONSTITUTION:When a halogenated silver emulsion film 4 is selectively exposed to be processed in developing and fixing solution and distilled water utilizing a contracted projection type aligner, silver patterns 4' are separated in gelatin at the exposed parts while the other silver patterns 4'' at the unexposed parts are resolved leaving gelatin only. After heating an Si substrate 1 in H2 at 150 deg.C, RIE is performed by using Ar+N2 and only silver paterns 4' are left. Next an SiO film 3 is etched utilizing CF4+He and masks 4'' and finally RIE is performed using O2 to open holes in an organic high molecular film 2 simultaneously etching the silver patterns 4'. In such a constitution, the halogenated silver emulsion film 4 may be exposed from around 0.1X10<-7>sec while it is being shifted improving the exposing function of a wafer by 5-10 times magnitude utilizing the contracted projection type aligner.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pattern forming method in a method of manufacturing semiconductor devices such as ICs and LSIs.

In a monolithic integrated circuit that incorporates a large number of semiconductor elements on a single semiconductor substrate, all the semiconductor elements therein have a planar structure.

This type of semiconductor device requires selective diffusion of impurities, opening of contact windows in the backside oxide film, formation of an insulating film to preserve the semiconductor surface, and exposing only the wiring layer at the bonding butt portion for taking out the final lead wire. It is formed through the following steps.

In recent years, the number of elements in semiconductor devices such as LSIs has increased dramatically - and accordingly, element patterns to be realized on semiconductor substrates have been forced to become finer.

However, negative photoresists made by adding cross-linking agents to imprene rubber, such as KMER manufactured by Eastman Kodak Company,
2001P made by Kasbar Co., Ltd.
Selective exposure is performed on the KMER using a contact exposure type aligner such as I, and then a resist pattern is formed by development processing. 3-4μ in conventional pattern formation method
Because it is difficult to realize the following fine patterns, in recent years the industry has adopted positive photoresists made by adding photosensitizers such as naphthoquinone diazide to phenolic novolac resins such as AZ1470, and as aligners manufactured by GCA Co., Ltd. Reduced projection type exposure apparatuses such as DSW4800 are increasingly being used. Here, the projection type aligner has a stage on which the semiconductor wafer is placed, and an illumination system and an optical system for reducing the element pattern of the semiconductor device and printing it on the wafer. The stage is moved intermittently while exposing one chip at a time. By employing the above-mentioned positive photoresist and reduced size exposure equipment, it is possible to realize patterns down to approximately 1.0 μm on a semiconductor substrate, significantly promoting the miniaturization of semiconductor elements.

Contributed to improving the functionality of semiconductor devices.

However, although the above-mentioned positive photoresists and reduced projection aligners have brought about revolutionary progress in the miniaturization of devices, the number of semiconductor wafers that can be exposed per unit time, that is, the processing capacity of the equipment It has the disadvantage that it is about 1/2 to 1/3 inferior to the conventional contact direct lighting method. For this reason.

This is because the stage on which the semiconductor wafer is placed is moved intermittently while exposing patterns that are one to several chips apart, rather than exposing all the patterns on the semiconductor wafer at once as in the conventional method. be. That is, after exposing a pattern of one chip to several chips, the stage is moved, and after moving a predetermined distance, the stage is stopped and the exposure is repeated. Since the exposure time and the moving time of the stage are long, the number of semiconductor wafers to be processed is significantly reduced.

In addition, because the reduced projection aligner has a complex mechanism, optical system, illumination system, and control electronic circuit, it requires a much larger area than conventional aligners, and the device itself The price has also become much more expensive, several times as expensive. Therefore, it is obvious that the above-mentioned drawback I has a negative impact on the cost of semiconductor devices processed by the reduction projection aligner.

The present invention has been made to solve the above problems, and is a novel method that improves the throughput of a reduction projection aligner by several times υ compared to the conventional system using positive photoresist. A pattern forming method is provided.

The pattern forming method according to the present invention makes it possible to perform exposure without stopping the stage during semiconductor wafer processing in a reduced projection aligner, so it is possible to significantly improve the processing capacity of the aligner. Become.

The present invention is characterized by a step of sequentially depositing an organic polymer layer, a silicon oxide film, and a silver halide emulsion film on the whole surface of a semiconductor substrate, and a step of mounting the substrate in a reduction projection type path light device. A process of performing exposure processing without stopping the stage;
The substrate is subjected to predetermined photographic development, fixing and stop treatments to selectively precipitate silver in the silver halide emulsion film, and oxidation is performed using the silver pattern as a mask in gas plasma of predetermined components. A pattern forming method in which a silicon film is selectively removed, and then an organic polymer film is selectively removed in a predetermined gas plasma using the silicon oxide pattern as a mask to form a predetermined core polymer film pattern. It is in.

Embodiments of the present invention will be described in detail below with reference to the drawings.

An organic polymer film 2 such as phenol borac resin is deposited on the whole surface of the silicon substrate 1 to a thickness of 1.5 to 2.0 μm by the spin cord method 9 (Fig. 1). A thin layer 3 of silicon oxide is deposited on the polymer layer 2 by vacuum evaporation to a thickness of 0.2 to 0.3 .mu.m.

(Figure 2) Silver halide was then mixed with gelatin on the thin layer. The silver halide emulsion film 4 was formed by the spin coding method.
Apply to a thickness of ~1.0μ. (FIG. 3) Next, the substrate 1 is selectively exposed to light using a reduction projection type aligner. In this case, the light source has an output of 2KW.

A xenon flash lamp with a lamp voltage of 26V is used. After that, a development process using a development method using handroquinone as the main component, followed by a fixing process using a fixer containing thio-intoxicating soda as a main component, and finally washing with pure water.
In the selectively exposed areas of the emulsion film 4, silver precipitates into the gelatin and becomes 4'); In the unexposed areas, the silver dissolves and remains only in the gelatin (Figure 4). . Subsequently, the silicon substrate 1 is heated in a hydrogen atmosphere at a temperature of 150° C. for about 20 minutes, and then processed using a gas plasma containing a mixture of argon and nitrogen in a parallel plate type reactive ion etching apparatus. In this case, the processing conditions include an electrode spacing of 10 to 1
5 cwL, gas pressure from 6 x 10-” to 10
X 10 Torr, the mixing ratio of argon and nitrogen is 1:
3 High frequency output is 100-120W.

After processing for 10 to 15 minutes under the above conditions, the gelatin film portion 4'' is removed, leaving only the silver pattern 4' (Fig. 5).Next, under the etching conditions of the reactive ion etching apparatus described above, the gas is and helium (mixing ratio 1:1)
) Gas pressure, 5X10″1~9.0×10-”fo
Then, the high frequency output was changed to 150 to 180 W, and the etching process was continued for about 10 to 12 minutes to remove the silicon oxide 3 at the bottom of the silver pattern 4'. (6th
Figure) Finally, during the etching conditions, the gas was oxygen and the gas pressure was 0.5.
When the etching process is performed by changing the pressure to 0.6 Torr, the organic polymer film 2 and the screen pattern 4' are removed except for the portion under the silver pattern 4'.

This allows only the selectively exposed portions of the organic polymer film 2 to be exposed.
Then, the silicon oxide film 3 remains, and an element pattern is formed (FIG. 7).

According to the present invention, during two-selective exposure, a strong xenon flash lamp photosensitive layer is used as a light source, and a silver halide emulsion having a sensitivity IO' to 10' times that of current photoresists is used. Change time from current 0.5 seconds to 0
．． It is possible to shorten the time to 1 to 0.2 x 1'0-' seconds. Therefore, when exposing with a reduction projection type aligner, there is no need to stop the stage each time as in the conventional case, and it is possible to perform one flash without moving it. This is because the moving speed of the stage of the aligner being towed is about the maximum speed per second. Exposure time 0.2 x 10. 'Distance traveled by the semiconductor substrate in seconds' is 50 cm/sec x 0.2 x 10
This is because when second=o, oiμ, the value becomes negligible, which is about 1/ of the minimum dimension of 1 to 2μ of the current element pattern.

For the above reasons, the pattern forming method according to the present invention
The ability to process the edge of a semiconductor wafer using the x1 reduction projection type aligner is significantly improved compared to the conventional method, reaching approximately 5 to 10 times.

For example, as the aligner, manufactured by GCA, USA, 8.
W4800 f, f, pf chair5. Oy, X
In the current situation, if a 5.0 sweetfish chip can be baked into a 4" sea urchin... Since the exposure time is 120 seconds and the stage movement time is about 30 seconds, a minimum of 150 seconds is required to process one wafer.

Therefore, in the current method, the exposure processing capacity of 4" wafers using the aligner is at most about 20 to 30 blanks per hour. On the other hand, according to the pattern forming method according to the present invention,
Since there is no need to stop the stage of the aligner, the processing time for one 4" wafer under the above conditions is at most 30 seconds. Therefore, the wafer processing capacity of this apparatus is 1 hour. fi, 120 sheets, which is about 5 to 6 times the current processing rate.

As described above, the pattern forming method according to the present invention makes it possible to increase the wafer processing capacity of a reduced projection aligner several times that of the conventional one.

This is a major contribution to reducing the cost of semiconductor devices.

[Brief explanation of drawings]

1 to 7 are cross-sectional views showing steps of an embodiment of the present invention. In Figure 1, 1... silicon substrate, 2...
...Organic polymer film%3...Silicon oxide thin film, 4.
...Silver halide emulsion film, 4'...pan,
4 "...Gelatin.

Claims (1)

[Claims] On one main surface of the semiconductor substrate, an organic polymer film, a silicon oxide film,
and a step of sequentially depositing a silver halide emulsion film, a step of performing an exposure process without stopping the stage on which the substrate is placed in a reduction projection type exposure device, and a step of developing the substrate in a predetermined photographic device. A step of selectively precipitating the silver in the silver halide emulsion film by performing fixing and stopping treatment, and selectively removing the silicon oxide film using the silver pattern as a mask in gas plasma of predetermined components. . Next, using the silicon oxide pattern as a mask, the organic polymer film is selectively removed in a predetermined gas plasma to form the predetermined polymer film pattern.