JPS5990850A - Solution for stripping resist pattern - Google Patents

Abstract

PURPOSE:To obtain the titled soln. capable of removing a resist pattern applied to a substrate without damaging a wiring layer under it by adding an org. solvent or surfactant to an aq. soln. of alkali. CONSTITUTION:(i) An about >=1% org. solvent, such as methanol or methyl ethyl ketone, or (ii) an about 1ppm-10% surfactant, such as polyethylene glycol nonylphenol ether is added to an aq. soln. of sodium phosphate or tetraethylammonium hydroxide. The soln. thus obtained is superior in stripping ability and it can be used in an automated device without attacking the wiring layer under the resist pattern and without danger.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for removing a resist pattern on a substrate, which is used in lithography for manufacturing semiconductor devices such as ICs and LSIs on a semiconductor substrate. Regarding.

[Technical background of the invention and its problems]

Conventionally, the common method for removing resist patterns is as follows:
(1) Stripping with a sulfuric acid-based stripping solution, (2) Stripping with a stripping solution containing a chlorine-based organic solvent as the main component, (3) Removal by ashing with oxygen plasma. Examples include methods. Hereinafter, the conventional techniques (1) to (3) above and their problems will be explained.

(1) In the case of a sulfuric acid-based stripping solution: First, it is difficult to use in an automated device because it evaporates the metal and the solution temperature is as high as about 180°C. Secondly, because of the above reasons, the delag method is used, which is dangerous because workers have to directly handle large amounts of sulfuric acid, and the peeling is not sufficient, and residual liquid that has been peeled off re-adheres. There is a fear that the country will leave Lesost. Thirdly, to save the metal,
For example, it cannot be used when removing a resist (e-turn) on an At wiring.

(2) In the case of a stripping solution containing a chromium-based organic solvent as a main component: This stripping solution is mainly used when stripping 9 turns of resist on an At wiring, for example, which is removed with a sulfuric acid-based stripping solution. However, first, it is used at a high temperature of about 100° C. or higher, so it is difficult to use it in automated equipment, as in the case of sulfuric acid systems. Second, the main ingredients, naltetrachlorethylene, dichlorobenzene, and the phenol added to these are all harmful and volatile organic solvents, so for the reasons mentioned above, when using the Dizzo method, workers is at risk. Third, since the stripping solution is harmful, rinsing with an organic solvent such as methanol or trifletone is required after stripping.
One more process.

(3) In the case of a sky fire using oxygen plasma: In this method, for example, a certain amount of oxygen is introduced into a cylindrical quartz reaction tube while reducing the pressure with a rotary pump, and high-frequency power is applied to an electrode placed outside the reaction tube. In this method, the resist layer is incinerated and removed by generating glazma and chemically reacting it with the renost/mother turn. Although this method has various advantages such as no waste liquid treatment unlike the wet method, it has the following drawbacks. First, since there is a difference in the degree of peeling of the resist pattern between the substrate and the surface, it is difficult to set the peeling time, and there is a possibility that a residue of the resist pattern may be generated. Second, the processing time for the aforementioned sulfuric acid-based or chromium-based stripper is approximately 25 minutes per 25 4-inch wafers, whereas ashing using oxygen plasma requires approximately 40 minutes. However, the processing capacity of the peeling device is low.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and has excellent stripping ability and does not damage the wiring layer under the resist/cuten, is non-hazardous, and can be used in automated equipment. The purpose of the present invention is to provide a stripping solution.

[Summary of the invention]

The resist/mother turn stripping solution of the present invention has a composition consisting of an alkaline aqueous solution and at least one kind selected from an organic solvent or a surfactant, so that it has excellent stripping ability and has a kt below the resist/mother turn. This design is intended to eliminate the need to dispose of any wiring layers, such as wires, etc., and to be non-hazardous and usable in automated equipment.

As the alkaline aqueous solution used in the present invention, an aqueous solution containing sulfur/lium phosphate or sodium silicate as a main component (
(inorganic alkali aqueous solution) or amine-based organic alkali aqueous solution such as tetramethylammonium hydroxide and trimethyl-2-hydroxyethylammonium hydroxide.

Organic solvents used in the present invention include glycol-based,
Alcohol-based, cellosol-based, ester-based, ketone-based,
Various types such as aromatic ones can be mentioned.

The surfactants used in the present invention include all types of ionic and nonionic surfactants.

In the stripping solution of the present invention, if the amount of organic solvent or surfactant added is too small, the compatibility between the resist and the stripping solution will be insufficient and no effect will be seen. Specifically, when adding only an organic solvent, the amount is less than 1 liter per alkaline aqueous solution, and when only a surfactant is added, the amount is less than 1 liter per alkaline aqueous solution.
If it is less than ppm, sufficient effects cannot be obtained. In addition, in the case of surface active MIJ, even if it is increased to 10% or more, the effect does not improve much and foaming occurs, so it is of no practical use. In the case of an organic solvent, for example, trimethyl-2-hydroxyethylammonium hydroxide is soluble in methanol, so it is also possible to use a 100% organic solvent instead of water.

The stripping solution of the present invention is used for stripping most of the positive type resists or some types of negative type resists and turns. In addition, the alkaline aqueous solution, which is the main component of the stripping solution 1) W of the present invention, originally has the ability to peel off most positive-type Rennosts or certain negative-type Rennosts to some extent, but this alone is insufficient. By further adding at least one of an organic solvent or a surfactant, it is possible to improve the conformability of the resist pattern at the interface and to greatly improve its peeling ability.

[Embodiments of the invention]

The resist pattern stripping solution of the present invention will be explained below.

For example, various positive photorenost films are applied on an St substrate in advance and subjected to glue baking treatment, and then exposed and developed using photophosphorography technology to form resist holes and turns, and then subjected to post-baking treatment. Thereafter, a wafer is prepared in which the underlying layer is etched or ion-implanted using the resist pattern as a mask. The resist edges and turns of such wafers were stripped using various stripping solutions of the present invention as shown in the table below.

When the surface of the wafer from which the resist pattern was peeled off was observed under a microscope as shown in the table above, it was found that in each of the examples, the resist pattern and turns were completely removed, and there was no residual resist pattern 9 at all. Hereinafter, the effects of the present invention will be explained in detail.

(1) When the stripping speeds of the conventional method and the stripping solution of the present invention were compared, the results were as shown in FIG.

(a) in the figure shows the stripping characteristic line using the stripping solution of the present invention (
b) shows the stripping characteristic line using sulfuric acid-based stripping solution, and (c
) shows a stripping characteristic line using a chromium-based stripping solution, and (d) shows a stripping characteristic line using an oxygen plasma ashing method. From the same figure, it can be seen that the peeling ratio of the present invention: t
It can be confirmed that the person has i ability.

(2) The peeling solution of the present invention; since it is an aqueous solution and has sufficient peeling ability at around room temperature as shown in FIG. 2, it can be used in an automated device such as a developing device. Therefore, the resist edges and turns can be removed cleanly without insufficient removal or resist residue. As a result, when we investigated the number of defective locations due to renost residue between the conventional stripping solution and the stripping solution of the present invention, we found that the number of defective locations was as shown in FIG. 3. In addition, in the figure (
, ) is the peeling characteristic line using the peeling solution of the present invention, and (b
) shows a stripping characteristic line using a sulfuric acid-based stripper, and (c) shows a stripping characteristic line using a chlorine-based stripping solution. As shown in the figure, the number of defective tubes can be reduced to zero by applying this stripping solution for approximately 14 seconds or more, confirming that the stripping ability is superior to that of the conventional method.

(3) 4-inch wafer 25 treated with conventional and inventive stripping solutions
When the strips were treated, the treatment time was 25 minutes with sulfuric acid-based stripper, 25 minutes with chlorine-based stripper 1411, and 40 minutes with oxygen f-zizma ashing, whereas when the stripper of the present invention was used, the treatment time was 15 minutes. It was confirmed that the processing time could be significantly reduced.

(4) Although the stripper of the present invention is generally strongly alkaline and requires caution such as wearing protective goggles when working, it is safer than sulfuric acid-based strippers and is similar to chlorine-based strippers. Since it is not harmful to the human body, there is little danger in handling. Further, it is possible to prevent the At wiring under the resist pattern from being damaged, for example, as in the case of the sulfuric acid-based stripper 141L liquid.

(5) In the case of a chlorine-based stripper, it is harmful and requires rinsing and then washing with water, whereas in the case of the liquid stripper 1-1 of the present invention, it is not harmful and only requires washing with water. ,
Therefore, the number of work steps can be reduced by one.

〔Effect of the invention〕

As described in detail above, according to the present invention, the resist pattern can be stripped with excellent stripping ability without damaging the wiring layer under the resist pattern, without any danger, and which can be used with automated equipment. It can provide ILG liquid.

[Brief explanation of drawings]

B4'f, Figure 1 is a characteristic diagram showing the relationship between the stripping time and the peeling thickness of the resist pattern, and Figure 2 is a characteristic diagram showing the relationship between the temperature of the stripping solution and the dissolution rate of Renost Gutan. , Figure 3 shows the relationship between peeling time and the number of defective locations in a 4-inch wafer? FIG. Applicant's agent Patent attorney Takehiko Suzue 1v! i Figure 2 Figure 3, j To Co # M Open)

Claims (1)

[Claims] A resist pattern stripping solution for removing a resist pattern formed on a semiconductor substrate, which is characterized by comprising an alkaline aqueous solution and at least one kind selected from an organic solvent or a surfactant.