JPH0667439A - Treating liquid for semiconductor surface - Google Patents

Abstract

PURPOSE:To decrease surface tension to improve wettability and to prevent foaming due to an additive by incorporating N-alkyl-2-pyrrolidone as a surfactant into a specified quaternary ammonium hydroxide soln. CONSTITUTION:The treating liquid essentially consists of quaternary ammonium hydroxide soln. expressed by formula [R1R2R3R4N]<+>.OH which is an org. alkali soln., and contains N-alkyl-2-pyrrolidone (N-alkyl group is an alkyl group of 6-20 carbon number) as a surfactant. In formula, R1-R4 may be same or defferent and are alkyl groups or hydroxyalkyl groups of 1-3 cxarbon number. Thereby, the treating liquid used as a developer suppresses the reduction rate of the film in an unexposed area and causes no foaming even wettability is improved by addition of the surfactant. Thus, a fine pattern can be formed without defect and the dimenasional variation of the pattern is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor surface treatment liquid, and more particularly to a semiconductor surface treatment liquid obtained by adding N-alkyl-2-pyrrolidone as a surfactant to an aqueous quaternary ammonium hydroxide solution. The above-mentioned treatment liquid of the present invention is a semiconductor surface treatment liquid that does not foam at all and can be efficiently treated in the treatment process, and is used as a positive photoresist developer for developing LSI and LCD, or a semiconductor surface cleaning liquid, a rinse. It is a semiconductor surface treatment liquid that can be used in a wide range of applications as a liquid or a stripping liquid.

[0002]

2. Description of the Related Art The recent development of the electronic industry has been remarkable, and the recent semiconductor integrated circuits are highly integrated as represented by ULSI and the minimum line width when drawing a circuit accompanying it is gradually miniaturized, and 16 megabits are required. 0.5 μm line profile for integrated circuits, 0.3 for next generation 64 Mbits
It is strongly required that a line profile of 5 μm be formed with high accuracy. An organic alkaline aqueous solution is used as a developer for the positive resist, for example, tetramethylammonium hydroxide (IBM “Technical Disclosu”).
re Bulettin ", Vol. 13, No. 7, 2009,
1970) and Choline (US Pat. No. 4,239,661)
Aqueous solution) is generally used.

However, when a pattern having a fine line width is drawn using a developing solution such as tetramethylammonium hydroxide or choline, the resist profile and dimensional accuracy are extremely reduced. Therefore, in order to increase the resist sensitivity, the alkali concentration of the developing solution is raised, the developing temperature is raised, or the developing time is lengthened, but the sufficient effect on the so-called throughput cannot be obtained.
In addition to this, various surfactants are added to the quaternary ammonium hydroxide aqueous solution as an improved technique for improving the resolution.
A compound added with an organic compound is proposed. A surfactant added is, for example, JP-A-58-91.
43, JP-A-61-70551, JP-A-61-15
1537, JP-A-61-167948, JP-A-61
No. 232453, JP-A No. 61-232454, JP-A No. 62-32452, JP-A No. 62-32454, and JP-A No. 62-47125. Surfactants and alcohols, hydrocarbons, etc. Other organic compounds added are, for example, JP-A-62-232453.
And JP-A-58-57128, and there are those in which various organic compounds are added. For example, JP-A-60-24105, JP-A-62-38755, and JP-A-62- Various proposals such as 57162 and JP-A-62-67535 have been proposed.

The developer containing the above-mentioned various surfactants and organic compounds improves the wettability to the resist surface, that is, lowers the surface tension, and causes a difference in dissolution rate between the UV-exposed area and the unexposed area. The purpose is to strengthen, that is, improve the sensitivity. However, in the submicron line profile technology required for the next generation, there is a problem that a surfactant or the like added for improving resolution and dimensional accuracy causes foaming to cause a profile defect. In addition to this, in recent years, the diameter of wafers has been increased to 6 to 8 inches, and it is required that the developing solution can be uniformly processed on the wafer in a short time.

On the other hand, in the semiconductor manufacturing process, it is widely practiced to use an alkaline solution for cleaning in order to remove surface stains. Since an alkaline solution is used as a treatment liquid, it is known that a surfactant, an organic compound or the like is added to improve its treatment ability. However, since surfactants generally have a foaming property, it is often the case that troubles in the cleaning step, rinsing step, and peeling step due to a large amount of generated foams and changes in processing conditions are unavoidable. Therefore, there are various cases in which a complicated process such as adding an antifoaming agent for the purpose of defoaming is required, and further, the antifoaming agent is expensive and the defoaming agent itself cannot obtain a sufficient effect. Have a problem. Further, as in the case of the developing solution, it is strongly desired to uniformly wash the wafer when the diameter of the wafer is increased.

[0006]

Therefore, the present invention is useful as a positive photoresist developing solution, an alkali cleaning solution, a stripping solution, etc., which has a low surface tension, improves wettability, and does not cause foaming due to additives. Another object is to provide a semiconductor surface treatment liquid. The surface treatment liquid of the present invention is used as a positive photoresist developer, an alkaline cleaning liquid, a stripping liquid, etc., and when used as a positive photoresist developer, it has low surface tension and improves wettability, and it is caused by an additive. Since no bubbles are generated, the film thickness reduction rate of the unexposed area is sufficiently suppressed, an excellent profile can be obtained, and the variation in pattern dimensions is small, so that the next-generation submicron pattern profile is sufficiently formed. Is. Also, when used as an alkaline cleaning solution, a stripping solution, etc., it has no foaming property compared to conventional alkaline cleaning solutions, there is no trouble in the processing step due to foaming, and there is no need to change the processing conditions. Moreover, it is a semiconductor surface treatment liquid which does not require addition of an antifoaming agent.

[0007]

[Means for Solving the Problems] As a result of intensive research from various viewpoints in view of the above circumstances, N-alkyl-2- as a surfactant is added to a quaternary ammonium hydroxide aqueous solution which is an organic alkaline aqueous solution. It has been found that a non-foaming semiconductor surface treatment liquid can be obtained by containing pyrrolidone, and the present invention has been completed.

[0008] The present invention has the general formula _{(1) [R 1 R 2} R 3 R 4 N] + · OH - ......... (1) ( _{where, R 1, R 2, R} 3 and R ₄ are the same Or an alkyl group having 1 to 3 carbon atoms or a hydroxyalkyl group), and N-alkyl-2-pyrrolidone as a surfactant in an aqueous quaternary ammonium hydroxide solution represented by It is the semiconductor surface treatment liquid contained.

The quaternary ammonium hydroxide aqueous solution represented by the above general formula (1) is specifically, tetramethylammonium hydroxide hydroxide, tetraethylammonium hydroxide hydroxide, tetrapropylammonium hydroxide hydroxide, water. Trimethylethylammonium oxide oxide, trimethylpropylammonium hydroxide hydroxide, dimethyldipropylammonium hydroxide hydroxide, monomethyltriethylammonium hydroxide hydroxide, monomethyltripropylammonium hydroxide hydroxide, trimethylhydroxyethylammonium hydroxide hydroxide Examples thereof include oxide and dimethylhydroxyethylammonium hydroxide. Of these, tetramethylammonium hydroxide (TMAH) and trimethylhydroxyethylammonium hydroxide hydroxide (choline) are preferable. The aqueous solution concentration of the above quaternary ammonium hydroxide used in the present invention is 0.05 to 15 wt%, preferably 0.1 to 6 wt%.

As the surfactant used in the present invention, N-alkyl-2-pyrrolidone represented by the following general formula (2) is used.

[0011]

[Chemical 1] (In the formula, R ₅ is an alkyl group having 6 to 20 carbon atoms) Specifically, N-hexyl-2-pyrrolidone, N-heptyl-2-pyrrolidone, N-octyl-2-pyrrolidone, N-nonyl-2 -Pyrrolidone, N-decyl-2-pyrrolidone, N-undecyl-2-pyrrolidone, N-dodecyl-2-pyrrolidone, N-tridecyl-2-pyrrolidone, N-tetradecyl-2-pyrrolidone, N-pentadecyl-2-pyrrolidone , N-hexadecyl-2-pyrrolidone, N-heptadecyl-2-pyrrolidone, N-octadecyl-2-pyrrolidone and the like.

These surfactants generally have a content of 0.1
Although it is used in the concentration range of ppm to 5000 ppm, the effect is usually sufficiently obtained in the concentration range of 0.5 ppm to 1000 ppm. In the present invention, when the amount of the surfactant added is less than the above 0.1 ppm, the wettability is poor,
In addition, the rate of reduction of the film thickness in the unexposed portion increases, which is not preferable.
On the other hand, when the amount is more than 5000 ppm, a phenomenon in which the surfactant remains on the wafer after development occurs, and the rinse amount in the subsequent process increases, which is not preferable.

When the semiconductor surface treating solution according to the present invention is used as a developing solution, it has good wettability, no bubble formation, no profile defects in submicron profile formation, and a film thickness of an unexposed portion. The rate of decrease can be significantly suppressed. Further, the treatment liquid of the present invention quickly degreases the semiconductor surface, removes contaminants from inorganic substances, organic substances such as photoresist, and cleans in a relatively short time, and further polishes and wraps it after lapping. It is also effective as a cleaning liquid and is excellent in that it has no foaming property, and its ripple effect is enormous and industrially useful.

The positive photoresist which is the object of the developing solution of the present invention is not particularly limited, but may be, for example, one containing a phenol copolymer novolac resin and a naphthoquinone diazide compound as constituent components. Objects of the treatment agent of the present invention include, for example, photoresist residue, copper plating chemicals, gold plating chemicals, nickel plating chemicals, solder plating chemicals, flux, oil, adhesives,
Markers, laminate resins and the like can be mentioned.

Examples and comparative examples of the present invention will be described below.

【Example】

Test Example 1 (foaming test) The foaming test was carried out by using a sample 5 in a 100 ml Nessler tube with a stopper.
After adding 0 ml and shaking vigorously for 30 seconds, the change with time of the height (mm) of bubbles from the liquid surface was measured and evaluated.
The results are shown in Table-1.

Test Example 2 As a developer, a 2.38% by weight aqueous solution of tetramethylammonium hydroxide (hereinafter abbreviated as TMAH) was used as shown in Table 1.
As shown in the figure, N- with different alkyl chains is used as a surfactant.
A developing solution containing alkyl-2-pyrrolidone was prepared.
In addition, as a comparison, a polyoxyethylene allyl ether type nonionic surfactant, Neugen EP-130A (first) is also used without adding the surfactant in the present invention and as a commonly used surfactant. Industrial Pharmaceutical Co., Ltd.
The surface tension test was carried out on the product prepared by adding TMAH 2.38%. At the same time, the surface tension was measured to confirm that the wettability was improved. The results are shown in Table-2.

[0017]

[Table 1] Table-1 Test No Alkyl addition amount (ppm) 0 min 1 min 3 min 5 min Evaluation chain 1-C ₈ H ₁₇ : 10 ppm 5 mm 0 mm 0 mm 0 mm ◎ 2-C ₈ H ₁₇ : 100 ppm 10 mm 0 mm 0 mm 0 mm ◎ to ○ 3 -C ₁₂ H ₂₅ : 100ppm 10 mm 9 mm 8 mm 7 mm ○ 4-CH ₃ : 100ppm 0 mm 0 mm 0 mm 0 mm ◎ * Ratio 1-0 mm 0 mm 0 mm 0 mm ◎ * Ratio 2-120 mm 75 mm 62 mm 62 mm XX * Comparative example 1 ... TMAH 2.38% * Comparative example 2 ... TMAH 2.38% to Neugen EP-130
Add 100ppm of A

[0018]

[Table 2] Table-2 Test No. Alkyl chain, concentration (ppm) Surface tension (dyne / cm) ─────────────────────────── ── 5 -C ₈ H ₁₇ : 10ppm 62.0 6 -C ₈ H ₁₇ : 100ppm 51.7 7 -C ₈ H ₂₅ : 100ppm 26.6 * Ratio 3 -CH ₃ : 100ppm 73.2 * Ratio 4 − 73.2 * Comparative 5-30.9 * Comparative Example 3 ... TMAH 2.38% with N-methylpyrrolidone
Addition of 100 ppm * Comparative example 4 ... TMAH 2.38% * Comparative example 5 ... TMAH 2.38% to Neugen EP-130
Add 100ppm of A

Example 2 (Evaluation Test as Developer) The developer used in the foaming test of Example 1 was subjected to lithographic evaluation. A 3-inch silicon wafer was coated with OFPR-800 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) containing an alkali-soluble novolac resin and a naphthoquinonediazide compound as constituent components by a spinner so as to have a film thickness of 1.2 μm, and the coating was performed in a clean oven at 80 ° C. for 30 minutes. After prebaking for a minute, an exposure process was performed using a contact exposure apparatus through a test chart reticle. Next, the developing solutions shown in Table 3 are automatically developed by NE-7000 (Takizawa Sangyo Co., Ltd.)
Developed) and a rinsing process was performed. Development and rinsing were maintained at 23 ° C. in a constant temperature bath. Then, the film thickness reduction rate of the unexposed portion was measured. The taper angle of the cross-sectional shape of the resist pattern after development and the state of the line profile were observed and measured with a scanning electron microscope. As is clear from Table 3, the developer of the present invention is very excellent in terms of the film thickness reduction rate of the unexposed portion and the resist taper angle.

[0020]

[Table 3] Table-3 Test No. TMAH Concentration Alkyl chain, concentration (ppm) (wt%) Thickness reduction of unexposed area resist scum Theta state Speed angle (A / min) (degree) 8 2.38 -C ₈ H ₁₇ : 10ppm 420 74 ○ 9 2.38 -C ₈ H ₁₇ : 100ppm 270 75 ◎ 10 2.38 -C ₁₂ H ₂₅ : 1ppm 400 77 ◎ * Ratio 6 2.38 − 600 70 × * Ratio 7 2 .38-680 74 ○ * Comparative Example 6 ... TMAH 2.38% * Comparative Example 7 ... TMAH 2.38% to Neugen EP-130
Add 100ppm of A.

Example 3 (Evaluation test as a developing solution) The same procedure as in Example 2 was carried out except that 5% by weight of an aqueous choline solution was used as a developing solution. The test results are shown in Table-4.

[0022]

[Table 4] Table-4 Test No. Choline concentration Alkyl chain, concentration (ppm) Unexposed area resist scum (wt%) Film thickness reduction Tape state Velocity angle (A / min) (degree) 11 5.00 -C ₈ H ₁₇ : 10ppm 420 74 ○ 12 5.00 -C ₈ H ₁₇ ： 100ppm 270 75 ◎ 13 5.00 -C ₁₂ H ₂₅ : 1ppm 390 76 ◎ ※ Comparison 8 5.00 − 580 68 × ※ Comparison 95 0.00-650 70 × * Comparative Example 8 ... Choline 5.00% * Comparative Example 9 ... Choline 5.00% to Neugen EP-130A
Is added at 100 ppm.

Example 4 (Wax Dissolution Test) Wax "Sky Wax 415" (trade name) manufactured by Nika Seiko Co., Ltd., which is widely used for lapping and polishing silicon wafers, was used in an aqueous TMAH solution to prepare N-alkylpyrrolidone. A dissolution test was carried out using a cleaning liquid containing. The test method is Sky Wax 415,
200 mg was dissolved in a mixed solution of 5 m shown in Table 5 below at a treatment temperature of 70 ° C. for 50 minutes to measure the amount of dissolution.

[0024]

[Table 5] Table-5 Test No. TMAH concentration Alkyl chain, concentration (ppm) Wax dissolution amount (wt%) (mg / 100m) 14 0.68 -C ₈ H ₁₇ : 800 ppm 387 15 0.68 -C ₈ H ₁₇ : 100ppm 386 16 1.40 -C ₈ H ₁₇ : 100ppm 771 17 0.68 -C ₁₂ H ₂₅ : 10ppm 402 18 0.68 -C ₁₂ H ₂₅ : 1ppm 400 19 1.40 -C ₁₂ H ₂₅ : 1ppm 797 * Comparative 10 0.68-375 * Comparative example 10 ... TMAH 0.68%.

Example 5 (Wax Dissolution Test) The same procedure as in Example 4 was carried out except that the mixed solution of Example 4 was replaced with an aqueous solution of choline. The results are shown in Table-6.

[0026]

[Table 6] Table-6 Test No. Choline concentration Alkyl chain, concentration (ppm) Wax dissolution amount (wt%) (mg / 100m) 20 0.68 -C ₈ H ₁₇ : 800 ppm 338 21 0.68 -C ₈ H ₁₇ : 100ppm 337 22 1.40 -C ₈ H ₁₇ : 100ppm 673 23 0.68 -C ₁₂ H ₂₅ : 10ppm 372 24 0.68 -C ₁₂ H ₂₅ : 1ppm 370 25 1.40 -C ₁₂ H ₂₅ : 1ppm 741 * Comparison 11 0.68-326 * Comparative example 11 ... Choline 0.68%. From the results shown in Tables 5 and 6, the cleaning liquid of the present invention can remove wax satisfactorily with a clearly small amount of surfactant.

[0027]

As a developer, the semiconductor surface treatment solution of the present invention sufficiently suppresses the film thickness reduction rate in the unexposed area and improves the wettability by the addition of a surfactant, but does not cause foaming at all and is fine. Form a pattern without causing defects,
In addition, the variation of the pattern size is small, and it has an effect of giving an excellent profile. further,
When used as a cleaning liquid, the cleaning power of wax is high,
Since there is no foaming, the surface condition after washing is very good.

Claims (3)

[Claims] 1. A compound represented by the general formula: [R ₁ R ₂ R ₃ R ₄ N] ⁺ · OH ⁻ (where R _{1 to} R ₄ may be the same or different,
A quaternary ammonium hydroxide aqueous solution represented by C1 to C3 alkyl group or hydroxyalkyl group) is used as a main agent, and N-alkyl-2 is used as a surfactant.
-Pyrrolidone (however, the N-alkyl group has 6 to 20 carbon atoms)
A non-foaming semiconductor surface treatment liquid containing the same. 2. N-alkyl-2-pyrrolidone is 0.1.
The semiconductor surface treatment liquid according to claim 1, which has a concentration range of ppm to 5000 ppm. 3. A compound represented by the general formula: [R ₁ R ₂ R ₃ R ₄ N] ⁺ .OH ⁻ (wherein R _{1 to} R ₄ may be the same or different,
A quaternary ammonium hydroxide aqueous solution represented by C1 to C3 alkyl group or hydroxyalkyl group) is used as a main agent, and N-alkyl-2 is used as a surfactant.
-Pyrrolidone (however, the N-alkyl group has 6 to 20 carbon atoms)
Positive type photoresist developing solution.