JPH03209715A - Resist developing method - Google Patents

Abstract

PURPOSE:To decrease the charged quantity in the surface of resist in a cleaning step after development and to remove minute dust more completely by sequentially performing the development with chemicals, cleaning with pure water, cleaning with the mixed liquid of alcohol and water and drying. CONSTITUTION:Developing liquid 5 is dropped on the center of a semiconductor substrate 1 which is fixed on a rotatable vacuum chuck 3 after exposure. The substrate is rotated at a low speed for a short time, and the developing liquid 5 is applied on the entire surface. The liquid swells up with surface tension. Then the rotation is stopped, and development is performed for a specified time. Thereafter, the substrate is rotated at an intermediate speed, and the developing liquid 5 is splashed away. Then pure water 8 is injected on the center of the substrate 1, and the developing liquid 5 is washed out. After the water cleaning step like the conventional step is finished in this way, aqueous solution of isopropyl alcohol 10 of about 10% in volume ratio is injected on the central part of the substrate 1. The substrate is rotated at the intermediate speed, and cleaning is performed. Then the substrate is rotated at a high speed as a conventional way, and spin drying is performed. As the alcohol used, a similar effect can be obtained with methyl alcohol or ethyl alcohol. The concentration of alcohol within a 10-50% range in volume ratio can be used.

Description

[Detailed Description of the Invention] (Summary) Regarding a resist development method, particularly a method for cleaning a substrate to be processed after resist development, the present invention relates to a resist development method, in particular a method for cleaning a substrate to be processed after resist development, by reducing the amount of charge on the resist surface in the cleaning step after development to improve the removal of fine dust. With the aim of perfecting the image, it consists of the following steps: development with a chemical solution, cleaning with pure water, cleaning with a mixture of alcohol and water, and drying.

[Industrial Application Field] The present invention relates to a resist developing method, and particularly to a method for cleaning a substrate to be processed after resist development.

As patterns become finer for higher integration of semiconductor devices, the presence of dust during pattern formation has become a cause of a significant decrease in manufacturing yield and reliability. Garbage removal has become an important issue.

[Conventional technology]

Conventionally, a resist film has been developed by a method described below with reference to schematic diagrams shown in FIGS. 2(a) to 2(d) for an example of the paddle method.

Referring to FIG. 2(a), the semiconductor substrate 1 that has been coated with the resist film 2 and exposed to light is fixed on a rotatable vacuum chuck 3, and first developed from the developing nozzle 4 guided above the center of the semiconductor substrate 1. liquid 5
is dropped, and the chuck 3 is rotated at low speed for a short period of time to spread the developer 5 over the entire surface of the substrate and to build it up by surface tension.

Refer to FIG. 2(B) Next, the rotation of the chuck 3 is stopped, and the resist film 2 is developed for a predetermined period of time using the developer 5 deposited on the substrate.

6 indicates an opening from which the resist has been removed.

Refer to FIG. 2(C) Next, the chuck 3 is rotated at medium speed to shake off the developer 5, and then pure water 8 is poured from the water washing nozzle 7 guided over the center of the substrate l to wash away the developer 5. .

Refer to FIG. 2(d) Next, after washing with water for a predetermined period of time, pouring of the pure water 8 is stopped, and the chuck 3 is rotated at high speed to spin dry the substrate.

[Problem to be solved by the invention]

However, according to the above-mentioned conventional method, it is easy to remove relatively large dust such as resist fragments generated during resist development and dust floating in the air, but
Fine dust of the following size is electrostatically attached to the surface of the resist film 2, which is charged due to mutual friction between the highly insulating resist film 2 and the pure water 8 in the water washing process, and cannot be removed by this water washing process alone. There is a problem in that the patterning process is not carried out and is sent to the accelerated etching process, reducing the accuracy and yield of patterning.

Therefore, an object of the present invention is to reduce the amount of charge on the resist surface in a cleaning step after development to more completely remove fine dust.

[Means to solve the problem]

The above-mentioned problem is solved by the resist developing method according to the present invention, which includes steps of sequentially performing development with a chemical solution, cleaning with pure water, cleaning with a mixture of alcohol and water, and drying.

[For production]

That is, in the method of the present invention, the final cleaning after development is performed using a mixed solution of alcohol and pure water.

When alcohol is mixed into pure water, the coefficient of friction against the resist decreases due to the surfactant effect, and the amount of charge on the resist surface due to friction between the resist and the cleaning liquid decreases. Furthermore, since the electrical conductivity of pure water increases due to the dissociation of alcohol, the electric charge on the resist surface is discharged through the cleaning liquid, thereby reducing the amount of electric charge on the resist surface. For the above reasons, the minute dust electrostatically attached before this cleaning process is easily removed, and the amount of electrostatically attached dust during this cleaning is also reduced, so that the developing process according to the present invention can be completed. However, the amount of fine dust adhering to the substrate sent to the next process is significantly reduced compared to the conventional method.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the schematic diagrams shown in FIGS. 1(a) to 1(e).

Refer to FIG. 1(a) In the paddle-type resist developing method to which the present invention is applied, first, as in the conventional method, a semiconductor substrate 1 having, for example, a positive resist film 2 that has been exposed is placed on a rotatable vacuum chuck 3. While dropping the specified developer 5 from the developing nozzle 4, the vacuum chuck 3 is fixed at 50 Or, p, m.
After rotating for about 2 to 3 seconds at the following speed to spread the developer 5 over the entire surface of the resist film 2 covering the substrate 1, the chuck 3 is stopped, and the developer 5 is continued to drip. 5 is raised on the entire surface of the resist film 2 by surface tension, and the dropping of the developer 5 is stopped. Then, the nozzle 4 is retracted.

Refer to FIG. 1(6) Next, with the rotation of the chuck 3 stopped, the resist film 2 is developed for about 40 to 90 seconds using the developer 5 placed on the top. Reference numeral 6 indicates an opening from which the resist has been removed by development.

Refer to FIG. 1(C) Next, the chuck 3 is rotated at a speed of about 50 Or, p, m to scatter and remove the developer 5, and then the chuck 3 is continuously rotated at a speed of about 500 r, p, m. Then, pure water 8 is poured from a water washing nozzle 7 guided onto the center of the substrate 1 to perform pure water washing for about 30 to 60 seconds. After that, the supply of pure water 8 is stopped and the nozzle 7 is retracted. Note that a dedicated rinsing liquid may be used for the pure water cleaning.

Refer to FIG. 1(d) After the water washing process similar to the conventional method described above is completed, in the method of the present invention, about 10% by volume of isopropyl alcohol (IPA) is applied from the alcohol washing nozzle 9 guided onto the center of the substrate l. Pure water containing 10% IPA aqueous solution 1
0, and cleaning is performed for about 20 to 30 seconds while rotating the chi'ray at a speed of about 50 Or, p, m. After the cleaning is completed, the nozzle 9 is retracted.

Referring to FIG. 1(e), the resist development according to the present invention is then completed by spin drying for about 40 to 60 seconds while rotating the chuck at a high speed of about 300 Or, p, m as before.

According to the above examples, development, water washing, alcohol aqueous solution washing,
As a result of inspection using a wafer surface inspection device, the number of particles of 0.3 μm or larger on a 6-inch substrate with a spin-dried resist film 2 was reduced to 1/2 to 2/3 of that obtained using the conventional resist development method. It has been confirmed that

The alcohol used in the aqueous alcohol solution is not limited to the isopropyl alcohol shown in the above examples, but methyl alcohol and ethyl alcohol can also be used to obtain the following effects.

Further, the concentration of alcohol can be in the range of 10 to 50% by volume.

Furthermore, the method of the present invention is not limited to paddle development, but can also be applied to spray development, dip development, and, of course, to development of negative resists.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to significantly reduce the amount of fine dust that adheres to the substrate to be processed after resist development is completed and sent to the next process, thereby reducing yield and reliability in the semiconductor device manufacturing process. It greatly contributes to improving sexual performance.

[Brief explanation of drawings]

FIGS. 1(a) to (e) are schematic process diagrams of an embodiment of the method of the present invention, and FIGS. 2(a) to (d) are schematic process diagrams of a conventional method. In the figure, ■ is a semiconductor substrate, 2 is a positive resist film, 3 is a vacuum chuck, 4 is a developing nozzle, 5 is a developer, 6 is an opening in the resist film, 7 is a water washing nozzle, 8 is pure water, 9 is alcohol Cleaning nozzle, 10 indicates 10% IPA aqueous solution. <Mido・+mu A (辂日月 n 方 j 大 一 1 C 用 Ita Shin) 2 degrees loss J (Figure misfiring ro month direction 3 major dar implementation 癙 1 2nd game of Katsuji Mendo Zuaki 2) Process moat diagram of conventional method

Claims (1)

[Claims] 1. A resist developing method comprising the steps of sequentially developing with a chemical solution, cleaning with pure water, cleaning with a mixed solution of alcohol and water, and drying.