KR100511928B1 - How to remove the cleaning liquid - Google Patents

Abstract

The present invention relates to a method of removing a cleaning liquid, and the method removes unnecessary materials remaining on a semiconductor substrate including a resist pattern after a development process using a rinse liquid. In the dry process of removing the cleaning solution remaining between the resist patterns, the surface of the resist pattern is shaken by shaking the cleaning solution between the resist patterns by vibrating means and various methods installed in the same chamber to remove the surface tension. After the rotary drying process, there is an effect of preventing the resist pattern from being collapsed by the surface extension of the cleaning liquid remaining therebetween.

In particular, there is an effect that can ensure the stability of the process when forming a fine pattern having a line width of 0.2μm or less.

Description

How to remove the cleaning liquid

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a resist pattern in a semiconductor manufacturing process. Particularly, before or during a rotation drying process, a cleaning solution remaining between resist patterns is shaken by various methods to make it suitable for forming a fine pattern having a line width of 0.2 μm or less. It relates to a cleaning liquid removal method.

Conventionally, the photolithography method which is generally used in forming a resist pattern on a semiconductor substrate is briefly described as follows.

Applying a liquid resist on a semiconductor substrate, aligning and exposing the resist, patterning by spraying a developer solution on the resist, and cleaning the unnecessary material remaining between the resist pattern, including on the semiconductor substrate with a cleaning solution After this, finally, the cleaning liquid remaining between the resist patterns is removed by a spin dry process.

In the photolithography method as described above, the resist pattern often collapses after the spin dry process. Such pattern collapse occurred frequently as the height of the pattern was larger and the width of the pattern was narrow, especially in the case of fine patterns of 0.2 μm or less.

The reason for the pattern collapse phenomenon will be described with reference to the accompanying drawings.

As shown in FIG. 1, the cleaning solution 3 remains between the resist patterns 2 on the semiconductor substrate 1 after the cleaning process. At this time, the surface of the cleaning liquid 3 is concave downward due to the hydrophilicity of the resist pattern 2 (see solid line) or convex upward (see dashed line). The hydrophilicity of the resist pattern 2 is obtained after the developing step using the developer.

The cleaning liquid 3 has different surface tensions according to its surface, and the force P received per unit area of the resist pattern 2 by this surface tension is expressed as follows.

P = σ / R --- ①

It is expressed as

In the above equation,? Represents the surface tension of the cleaning liquid, and R represents the radius of curvature of the surface of the cleaning liquid 30, respectively.

The radius of curvature R is

R = d / (2cosθ) --- ②

It is expressed as

In the above formula, d denotes the distance between the resist patterns 2, and θ denotes the contact angle of the cleaning liquid 3 on the resist surface, respectively.

Substituting the above ② expression into the ① expression,

P = 2σcosθ / d

to be.

Referring to the above Equation 1, the surface tension σ and P are proportional to each other. The larger the surface tension of the cleaning liquid 3 remaining between the resist patterns 2 is, the larger the spin-drying process is for removing the cleaning liquid 3. Shows that the resist pattern 2 easily collapses.

This is because, in the case of a fine resist pattern of 0.2 µm or less, the surface tension of the remaining cleaning liquid 3 is greater than that of the semiconductor substrate 1 and the resist pattern 2.

The collapse of the resist pattern 2 proceeds in different directions depending on the surface shape of the cleaning liquid, as shown in FIGS. 2 and 3.

FIG. 2 shows a case where the surface of the cleaning liquid remaining between the resist patterns is concave down, and FIG. 3 shows a case where the surface of the cleaning liquid remaining between the resist patterns is convex upward.

Brief description of the conventional methods and their problems presented in order to prevent the collapse of the resist pattern 2 as described above is as follows.

First, the temperature of the cleaning solution is increased or a surface active agent such as an organic solvent or perfluorohexane (PHF) is added to the cleaning solution to reduce the surface tension of the cleaning solution itself. In this method, it is technically very difficult to control the surface tension by changing the composition of the cleaning solution itself, and compatibility with the actual process has been a problem.

Second, the photoresist is used to increase the Young's modulus of the resist itself, or to resist the negative pressure of the cleaning liquid by forming the resist into a multi-layer. This method has a problem that the development of the photoresist that can overcome the negative pressure of the cleaning solution is not practical because it takes a lot of time and cost, and there is a problem that the production cost is increased to form a resist in multiple layers.

Third, since pure water is usually used as the cleaning liquid, the resist is selected as a material having a low hydrophilicity. This method is not practical because the development of a new hydrophilic resist is time-consuming and expensive.

An object of the present invention is to reduce or remove the surface tension of the cleaning solution in order to avoid collapse of the resist pattern after the rotary drying process for removing the cleaning solution remaining between the resist pattern to solve the above problems. There is this.

In order to solve the above problems, the cleaning solution removing method according to the present invention comprises the steps of applying a resist on a semiconductor substrate; Patterning the resist to form a resist pattern; Cleaning the resist pattern; Applying a vibration to the resist pattern; It characterized in that it comprises a step of drying by rotating the resist pattern.

Hereinafter, a method for removing the cleaning liquid remaining between the resist patterns according to the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 4, in the developing apparatus, a resist of the semiconductor substrate 21 placed on the vacuum chuck 14 from the vibrating means 12 provided above the inside of the chamber 10 before or during the rotary drying process. Vibration waves are supplied to shake the cleaning liquid (solid or dashed line) 25 remaining between the patterns 23.

The semiconductor substrate 21 is rotated at a constant speed by driving the rotary motor 18 connected to the vacuum chuck 14 and the rotary shaft 16.

The vibration means 12 includes an electromagnetic wave generator and an ultrasonic wave generator, and the vibration wave supplied therefrom is directly transmitted to the remaining cleaning liquid 25 between the resist patterns 23 so that the surface of the cleaning liquid 25 is shaken. do.

In addition, the vibrating means 12 may be additionally installed in the chamber 10 or may be installed as a separate device, and may adjust the surface tension of the cleaning liquid 25 by changing the frequency and wavelength.

In addition to the vibration means 12, vibration generated during rotation of the semiconductor substrate 21 by the rotary motor 18 in the drying process may be used to shake the cleaning liquid 25. Such a method may realize an optimal condition for reducing or removing the surface tension of the cleaning liquid 25 by simultaneously adjusting the rotation rate of the semiconductor substrate 21 and the frequency, amplitude, and ambient temperature of the vibration means 12. .

In addition, the cleaning liquid 25 may be shaken by shaking the semiconductor substrate 21.

When the cleaning solution 25 remaining between the resist patterns 23 is shaken during the drying process in the above-described manner, the surface of the cleaning solution 25 becomes unstable in an unbalanced state, thereby reducing or eliminating the surface tension.

Thus, the surface of the cleaning liquid, as shown in Fig. 5, has a flat surface of an unstable non-equilibrium state.

The surface tension? Of the cleaning liquid 25 having such a flat surface is calculated as follows.

P = σ / R --- ①

R = d / (2cosθ) --- ②

Substituting ② into ①

P = (2cosθ) σ / d --- ③

Cosθ = 0 at ③ (because θ = 90 °)

Therefore, P = 0, and therefore σ = 0.

This is because the resist pattern 23 on the semiconductor substrate 21 undergoes a rotary drying process for removing the cleaning liquid 25 from the substrate 21, as shown in FIG. It does not collapse by

The cleaning liquid removal method in the photolithography process according to the present invention as described above is to shake the surface of the cleaning liquid remaining between the resist patterns before or during the rotation drying process to make the surface flat, that is, the surface tension By reducing or eliminating the effect, the resist pattern is prevented from collapsing due to the surface tension of the cleaning liquid during the rotary drying.

In addition, there is an effect that can be easily added to the vibration means additionally to the current developing apparatus.

In addition, the pattern development technique can be applied to the stable formation of the line width less than 0.2μm, thereby increasing the margin of the process.

It also has the effect of reducing the time and expense required to supplement other existing technologies and develop new materials.

In particular, it is expected to help a lot in the lithography process using X-rays and electron beams, which are considered to be applied in the next generation.

1 is a longitudinal sectional view showing a cleaning liquid remaining between resist patterns on a semiconductor substrate after a cleaning process using a conventional cleaning liquid.

FIG. 2 is a longitudinal cross-sectional view of FIG. 1 in which the resist pattern is bent by the surface tension of the cleaning liquid when the surface of the cleaning liquid is a solid line during the drying step;

FIG. 3 is a longitudinal sectional view of FIG. 1 in which the resist pattern is bent by the surface tension of the cleaning liquid when the surface of the cleaning liquid is dotted in the drying step; FIG.

4 to 6 are longitudinal cross-sectional views showing a method for removing a cleaning liquid remaining between resist patterns on a semiconductor substrate according to the present invention without collapse of the resist pattern;

Fig. 4 is a longitudinal sectional view showing that the cleaning liquid between the resist patterns is shaken by vibrating means installed in the chamber before or during the rotary drying process.

5 is an enlarged view of 'A' in FIG. 4.

Fig. 6 is a longitudinal sectional view showing the shape of a resist pattern on a semiconductor substrate after the rotary drying step;

** Description of the main parts of the drawing **

10 chamber 12 vibration means

14: vacuum chuck 16: rotation axis

18: rotating motor

21 substrate 23 resist pattern

25: cleaning liquid

Claims (5)

Applying a resist onto the semiconductor substrate 21; Patterning the resist to form a resist pattern (23); Cleaning the resist pattern (23); Applying vibration to the resist pattern (23); And a step of rotating and drying the resist pattern (23). The method of claim 1, wherein the step of cleaning the resist pattern (23) and applying vibration to the resist pattern (23) is performed in the same chamber (10). 2. The vibration of claim 1, wherein the vibration causes the surface of the cleaning liquid 25 remaining between the resist patterns 23 to shake using the vibration means 12 provided above the chamber 10 of the conventional developing apparatus. Washing liquid removal method, characterized in that. The method of claim 3, wherein the vibrating means (12) is one of an ultrasonic wave generator and an electromagnetic wave generator. The method of claim 1, wherein the cleaning liquid (25) is shaken using vibration of the semiconductor substrate (21) which rotates during the rotation drying step.