JPH04346352A - Developing solution for photoresist - Google Patents

Abstract

PURPOSE:To increase resolution and form an excellent pattern by mixing a specified compound of a specified amount with alkaline water solution. CONSTITUTION:A compound indicated by the equation I is mixed by an amount of 50 to 5000ppm with alkaline solution. In the equation, R is an aliphatic hydrocarbon radical with the number of carbons of 4 to 18, X is a group indicated by -CH2-CH2-O-, Y is a group indicated by -CH(CH3)-CH2-O-, k and 1 are integers of 3 to 40 same with or different from each other, m and n are integers of 1 to 30 same with or different from each other, and (m+n):(k+1)=2:8 to 7:3. As the alkaline solution, water solutions of alkaline metal hydroxide such as sodium hydroxide, potassium hydroxide, etc., those of amines, etc., such as propyl amine, butyl amine, di-n-butyl amine, triethylamine, etc.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer for photoresists.

0002

[Prior art and problems to be solved by the invention] In recent years,
In the field of microelectronics, the degree of integration of integrated circuits is rapidly increasing. Therefore, the photoresist used for pattern formation is required to have high resolution, and generally a positive resist is used, which is a combination of a resin soluble in an alkaline aqueous solution and a naphthoquinonediazide compound as a photodegrading agent. Also,
Negative resists that are soluble in alkaline aqueous solutions have also been developed with improved resolution.

[0003]Alkaline aqueous solutions are used as developing solutions for such photoresists, but when the pattern is minute, the alkaline aqueous solution cannot sufficiently soak the base of the pattern, leading to problems such as cutting of the base and poor dimensional accuracy. It has the disadvantage that it decreases. Therefore, it has been proposed to add various surfactants to the alkaline aqueous solution to improve the wettability of the photoresist. However, in that case, the added surfactant lowers the development speed of the photoresist and impairs productivity. Furthermore, the ratio of dissolution rates between exposed areas and non-exposed areas, that is, the dissolution selectivity may be lowered in some cases. This becomes a big problem as patterns become finer. Furthermore, foaming tends to occur, and the resulting foam may cause poor development.

[0004]Therefore, there has been a strong desire to develop a photoresist developer that exhibits good wettability and less foaming without reducing the photoresist development rate and solubility selectivity.

[0005]

[Means for Solving the Problems] The present inventors have continued intensive research to solve the above problems. As a result, they discovered that the problem could be solved by blending a specific compound into an alkaline aqueous solution, and came to propose the present invention.

That is, the present invention provides an alkaline aqueous solution with the general formula

[0007]

[Case 2]

(In the formula, R is an aliphatic hydrocarbon group having 4 to 18 carbon atoms, X is a group represented by -CH2 -CH2 -O-, and Y is -CH(CH3)-CH2 -O-.
is a group represented by -, and k and l are the same or different 3-
is an integer of 40, and m and n are the same or different from 1 to 30
is an integer of (m+n):(k+l)=2:8~7:
It is 3. ) 50 to 5000 ppm
This is a photoresist developer containing the following ingredients:

[0009] As the alkaline aqueous solution in the present invention, those conventionally known as photoresist developers can be used without any limitations. Specifically, aqueous solutions of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; aqueous solutions of amines such as propylamine, butylamine, dibutylamine, and triethylamine; or trimethyl(2-hydroxyethyl)ammonium hydroxide; These include aqueous solutions of quaternary ammonium compounds such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. Of these, especially trimethyl (2
Preference is given to using an aqueous solution of a quaternary ammonium compound such as -hydroxyethyl) ammonium hydroxide or tetramethylammonium hydroxide. Also,
An aqueous solution containing a combination of two or more of the above various alkaline compounds may be used. The concentration of the alkaline compound in the alkaline aqueous solution is preferably 0.1 to 10% by weight, preferably 1 to 5% by weight.

The greatest feature of the present invention is that the above alkaline aqueous solution contains the general formula

[0011]

[Chemical formula 3]

(In the formula, R is an aliphatic hydrocarbon group having 4 to 18 carbon atoms, X is a group represented by -CH2 -CH2 -O-, and Y is -CH(CH3)-CH2 -O-.
is a group represented by -, and k and l are the same or different 3-
is an integer of 40, and m and n are the same or different from 1 to 30
is an integer of (m+n):(k+l)=2:8~7:
It is 3. ) is included. In the above general formula, the aliphatic hydrocarbon group of R has 4 to 4 carbon atoms.
18, preferably 8 to 14, and linear or branched saturated or unsaturated ones can be used without restriction. However, if the number of carbon atoms in the aliphatic hydrocarbon group is less than 4, the wettability of the developer to the photoresist will be insufficient, while if the number of carbon atoms is more than 18, it will be difficult to dissolve in an alkaline aqueous solution, which is undesirable. .

In the above general formula, X, that is, k and l representing the number of repeating ethylene oxide units are the same or different integers of 3 to 40. When the values of k and l are each smaller than 3, the compound represented by the above general formula becomes difficult to dissolve in an alkaline aqueous solution, and when it is larger than 40, leakage to photoresist becomes insufficient. Further, Y, that is, m and n representing the repeating number of propylene oxide units are the same or different integers of 1 to 30.

When the values of m and n are larger than 30, the compound represented by the above general formula becomes difficult to dissolve in an alkaline aqueous solution.

Further, in the compound represented by the above general formula, (m+n):(k+l), which represents the repeating ratio of propylene oxide units and ethylene oxide units, is 2:8 to 7:3. When the proportion of propylene oxide units is less than 2, the compound represented by the above general formula tends to foam, and when it exceeds 7, it becomes difficult to dissolve in an aqueous alkaline solution.

Among the compounds represented by the above general formula, those preferably used are as follows.

[0017]

[C4]

[0018]

[C5]

[0019]

[C6]

[0020]

[C7]

[0021]

[Chemical formula 8]

[0022]

[Chemical formula 9]

[0023]

[Chemical formula 10]

[0024]

[Chemical formula 11]

[0025]

[Chemical formula 12]

[0026]

[Chemical formula 13]

[0027]

[Chemical formula 14]

[0028]

[Chemical formula 15]

[0029] etc.

In the present invention, the compounding amount of the compound of the general formula is 50 to 5000 ppm, based on the alkaline aqueous solution.
Preferably it is 100 to 3000 ppm. If this blending amount is less than 50 ppm, the wettability of the above-mentioned developer to the photoresist becomes insufficient;
If it is larger than 0 ppm, the development speed of the photoresist will decrease and foaming will increase.

The developer of the present invention can be applied to both positive and negative types without any limitation as long as it is an alkaline aqueous solution soluble photoresist. It is preferably applied to a positive resist in which a naphthoquinone diazide compound is combined with an alkaline aqueous solution-soluble resin. Examples of the alkaline aqueous solution-soluble resin include novolak resin, polyhydroxystyrene, and derivatives thereof. Further, examples of the above-mentioned negative resist include those in which a resin soluble in an alkaline aqueous solution is combined with a bisazide compound such as 4,4'-diazidodiphenyl sulfide or 4,4'-diazidophenylmethane.

The developing method using the developer of the present invention is not particularly limited, and known methods such as the immersion method and the paddle method can be applied.

The developing solution of the present invention may contain additives commonly used in conventional developing solutions, if desired. Examples of such additives include wetting agents, stabilizers, solubilizing agents, and the like, and these can be added alone or in combination of two or more.

[0034]

[Effects] The photoresist developer of the present invention has good wettability to photoresist and good photoresist development speed. Further, no decrease in solubility selectivity was observed. Therefore, when this developer is used for photoresist, for example, a good pattern with high resolution can be produced without the pattern base being trailed or developing not being completed within the development time and leaving undeveloped parts. can be formed. In addition, since the developing solution has little foaming, it is easy to operate when pouring into a container or transferring the solution, and it is extremely useful because there are no development defects caused by the generation of bubbles during development.

[0035]

EXAMPLES In order to explain the present invention more specifically, Examples and Comparative Examples will be given below, but the present invention is not limited to these Examples in any way. Example 1~
12 and Comparative Examples 1 to 5

A compound represented by the general formula shown in Table 1 was added to a 2.4% by weight aqueous solution of tetramethylammonium hydroxide.
A developer was prepared containing the amounts shown in . The prepared developer solution was shaken and the degree of foaming was observed.

Next, a positive photoresist containing a combination of novolac resin and naphthoquinone diazide compound was applied onto the silicon wafer to a thickness of 1.3 μm, and then prebaked at 90° C. for 30 minutes in a clean oven. A stepper (manufactured by Nikon Corporation) is placed on this silicon wafer.
After baking the pattern with SR1505G), development was carried out using the developer prepared above using the immersion method at a solution temperature of 22° C. for 1 minute. The photoresist pattern thus obtained was observed using a scanning electron microscope to evaluate the pattern shape, the presence or absence of development residue, and the state of edge breakage at the base of the pattern.

[0038] Separately, a silicon wafer that had been subjected to only the prebaking was prepared, and the developer was dropped onto the prebaked photoresist of the wafer. Next, in order to check the degree of wetting of the dropped developer onto the photoresist, the contact angle of the developer was measured using a contact angle meter.

In this case, the smaller the contact, the better the wettability.

The above results are shown in Table 1. In addition, in Table 1, the shape of the pattern is defined as ○ if the pattern base was well cut and the shape was good when observing the pattern, and on the other hand, if the pattern base was hemmed or the shape was poor. Those that were present are indicated as ×.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

Claims (1)

[Claims] Claim 1: In an alkaline aqueous solution, a compound of the general formula [Formula 1] (wherein R is an aliphatic hydrocarbon group having 4 to 18 carbon atoms, and , Y is a group represented by -CH(CH3)-CH2-O-, k and l are the same or different integers of 3 to 40, m and n are the same or different integers of 1 to 30, (m+n):(k+l)=2:8 to 7:3.)
A photoresist developer containing 50 to 5000 ppm of the compound represented by: