JPH0430739B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to an improved method for manufacturing a semiconductor device that enables formation of a resist pattern more precise than conventional methods. It is.

[Technical Background of the Invention] In order to increase the degree of integration and yield of semiconductor devices, it is necessary to advance and mature semiconductor device manufacturing technology centered on lithography technology. In order to improve, it is necessary to mature lithography technology.

2. Description of the Related Art Hitherto, the lithography process of mass-produced semiconductor devices, particularly the resist pattern forming process, has been carried out by the following method, as is already well known. That is, after forming a resist film made of, for example, a negative resist on the main surface of a semiconductor substrate or on an oxide film of the substrate, selective exposure is performed using a mask with a predetermined pattern, and then the semiconductor is further exposed using a spinner or the like. While rotating the substrate, a xylene-based developer is dropped onto the semiconductor substrate to develop the exposed portion of the resist film, and subsequently, while rotating the semiconductor substrate, a rinsing solution containing acetate is dropped. A predetermined resist pattern is formed on the semiconductor substrate by cleaning the non-exposed portions of the resist film.

In such conventional resist pattern forming processes, it is common to perform the development process and the rinsing process consecutively using the same spinner at the same rotational speed. There is no change in the result of resist pattern formation even if the resist patterns are slightly overlapped, so in order to improve production efficiency, a method is also used in which the final stage of the developing process and the initial stage of the rinsing process are slightly overlapped. However, keeping the spinner rotation speed constant even in the latter method (i.e., a method in which the developing process and the rinsing process are slightly overlapped) is different from the former method (i.e., in which the developing process and the rinsing process are not overlapped). It's the same.

[Problems with Background Art] The conventional method described above (that is, the resist pattern forming method in which the spinner rotational speed is kept constant throughout the developing process and the rinsing process) has the following problems.

In the development process, a volatile developer that is dropped onto the semiconductor substrate dissolves the unexposed resist film portion, evaporates into vapor, and is discharged outside the development chamber by a vacuum evacuation device, etc. Of the developer that has been shaken off from the substrate, the developer that has adhered to the walls of the development chamber, or the developer that has been dripped just before the rinsing process is discharged outside the development chamber is delayed, and these residual developer vapors are removed from the rinsing process. A phenomenon occurs in which the material is cooled and liquefied at the beginning of the process, and then re-attached to the semiconductor substrate. For this reason, the photoresist that had been dissolved in the developer re-deposit, and as shown in FIG.
may remain, resulting in poor pattern formation. In FIG. 1, 1 is a semiconductor substrate, 2 is a SiO ₂ film, and 3 is a resist pattern.

Therefore, in order to solve these problems, attempts have been made to prevent the developer vapor from re-liquefying, to rapidly exhaust the vapor, to change the spinner rotation speed, etc., but a complete solution has not been achieved. Among these various attempts, it became clear that when the spinner speed in the development and rinsing steps was increased, the unexposed resist could not be completely removed unless the development and rinsing times were increased. Conversely, it has been found that when the rotational speed of the spinner is lowered, a phenomenon occurs in which unexposed resist is redeposited around the semiconductor substrate.

[Object of the Invention] An object of the present invention is to solve the above-mentioned problems and provide an improved method for manufacturing a semiconductor device that does not cause defects in resist pattern formation.

[Summary of the Invention] As a result of repeated experiments in which the formation state of a resist pattern was observed while varying the spinner rotation speed, the present inventor found that the method of the present invention completely suppresses the resist re-deposition phenomenon described above. I discovered that it can be suppressed. As described in the claims, the method of the present invention includes a development-rinse overlap step in which a developer and a rinse are supplied simultaneously between the development and rinsing steps.
The present invention is characterized in that the spinner rotational speed in the development-rinse overlap step is increased to a speed four times or more higher than the spinner rotational speed in the development and rinsing steps. According to the method of the present invention, no reduction in resist redeposition occurs at all, and as a result, the incidence of defective products due to defective resist patterns is significantly reduced.

[Example of the Invention] A large number of semiconductor substrates were prepared as test pieces, and a negative resist was coated on the semiconductor substrates to a predetermined thickness, and then baked to form a resist film.
Furthermore, a latent image of the predetermined pattern was formed on the resist film by selectively exposing the resist film to a predetermined pattern using an exposure device.

Next, the semiconductor substrate was attached to a spinner of a developing device, and development was performed by spraying a xylene-based developer onto the resist film on the semiconductor substrate while rotating the spinner at 1000 rpm.

After 10 seconds had elapsed, an acetate ester rinse solution was sprayed for 5 seconds in addition to the developer spray. In this development-rinse overlap process, the spinner rotation speed is adjusted for each group of specimens.
It was varied in the range of 1000rpm to 5000rpm.

Next, the spraying of the developer is stopped and only the rinsing solution is sprayed, and the spinner rotation speed is increased.
The speed was reduced to 1000 rpm, and rinsing was performed at this rotational speed.

After 10 seconds had elapsed, spraying of the rinse liquid was stopped and the spinner rotation speed was increased to perform drying.

When examining the relationship between the incidence of defective products due to defective resist pattern formation and the spinner rotation speed in the development-rinse overlap process for each test piece that underwent the above steps, we found that:
A graph as shown in FIG. 2 was obtained.

In Figure 2, the vertical axis is the value of the good product rate ε (%) with no defects in the resist pattern, and the horizontal axis is the spinner rotation speed N in the development-rinse overlap process.
(rpm), and the curve shows the relationship between ε and N.

From FIG. 2, it can be seen that when the spinner rotation speed in the development-rinse overlap step is 4000 rpm or more, the non-defective product rate becomes approximately 100% and becomes saturated. Therefore, a development-rinse overlap process is provided, and the spinner rotation speed in this process is
If the rotation speed is set to 4000 rpm or more, the rate of defective products due to poor formation of resist patterns can be reduced to almost zero. Incidentally, in the conventional manufacturing method, the above-mentioned good product rate is at most 95%, and it is inevitable that a 5% defective product rate occurs.

[Effects of the Invention] As explained in the above embodiments, according to the method of the present invention, the incidence of defective products due to resist pattern formation defects, which could not be eradicated in the past, can be reduced to almost zero. As a result, the yield in manufacturing semiconductor devices can be improved, and more precise patterning and higher integration have become possible.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a semiconductor device having a resist pattern formed by a conventional method, and FIG. 2 is a graph for explaining the effects of the method of the present invention. DESCRIPTION OF SYMBOLS 1... Semiconductor substrate, 2... SiO ₂ film, 3... Resist pattern, 3a... Opening (of resist pattern 3), 4... Redeposited resist.

Claims (1)

[Scope of Claims] 1. After performing selective exposure on a photoresist film deposited either on the main surface of a semiconductor substrate or on a film formed on the main surface of a semiconductor substrate, using a spinner, In a method for manufacturing a semiconductor device in which a resist pattern is formed by developing and rinsing the semiconductor substrate while rotating the semiconductor substrate, the developing method includes simultaneously supplying a developing solution and a rinsing solution between the developing step and the rinsing step. - A semiconductor device characterized in that a rinse overlap step is provided, and the spinner rotation speed in the development-rinse overlap step is increased to a speed four times or more of the spinner rotation speed in the development step and the rinse step. manufacturing method.