JPH07302744A - Chemical solution treating method and device of semiconductor wafer - Google Patents

Abstract

PURPOSE:To improve the efficiency of releasing the resist adhering to semiconductor wafers as well as an organic matter treating efficiency while avoiding the inverse pollution by the organic impurities by taking a purging step of a mixed chemical polution for removing the organic matter covering the semiconductor wafer. CONSTITUTION:A treating 11 containing a mixed chemical solution is provided for treating a semiconductor wafer. Both sulfuric acid and hydrogen peroxide for treatment with the mixed chemical solution 10 are contained in a quartz- made treating vessel 12. Next, a carrier 20 containing a lot of semiconductor wafers W mounted on a supporting part 21 is immersed in the quartz-made treating vessel 12. Next, a heating part 19 is actuated to lead-in a purging material e.g. helium gas from a purging material feeding mechanism 23. Through these procedures, the carrier 20 containing a lot of semiconductor wafers W is immersed in the quartz-made treating vessel 12 so that any coated organic matter, etc., may be volatilized and released simultaneously leading-in fine and foamy purging material for purging the semiconductor wafer mixing chemical solution 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a chemical for treating a semiconductor wafer and a treatment apparatus therefor, and is particularly suitable for improving the chemical treatment of a semiconductor wafer used in a resist stripping step and an organic impurity removing step. .

[0002]

2. Description of the Related Art A method of manufacturing a semiconductor device is roughly divided into a pre-process for introducing and diffusing a predetermined impurity into a semiconductor wafer to form an active device, a passive device or both, and a post-process for assembling such a semiconductor device. To be done. In order to meet many demands related to fine processing with the increase in the degree of integration of semiconductor elements,
The photolithography process, which is consistent with the previous process, is still an essential technology. Regarding the resist stripping applied to this process, so-called oxygen plasma ashing (Ashin
In addition to g), a wet stripping process using a solvent is also used.

As a chemical solution for removing the organic impurities and the resist adhering to the semiconductor wafer by the photolithography process or the like, sulfuric acid (H ₂ SO ₄ ) and hydrogen peroxide (H ₂ O) are used.
A mixture containing ₂ ) is used. The structure of the chemical processing apparatus 50 for semiconductor wafer processing using this method will be described with reference to FIG.

The quartz treatment tank 51 is provided with weighing tanks 52 and 53 for sulfuric acid and hydrogen peroxide as chemicals together with a flow meter (not shown), and the drain 5 is provided at the bottom of the quartz treatment tank 51.
4, and a support part 57 for supporting the carrier 56 containing the semiconductor wafer W is provided on the side wall 58 of the quartz treatment tank 51 in addition to the heating portion 55 provided near the bottom of the quartz treatment tank 51.

Further, the quartz processing tank 51 has a weighing tank 5
After a predetermined amount of sulfuric acid and hydrogen peroxide from 2 and 53 is put into a mixed liquid 59 having a volume ratio of 9: 1, a carrier 56 containing one lot of semiconductor wafer W is put and placed on a supporting portion 57, It is heated to 140 ° C. to 145 ° C. by the heating unit 55 and processed for about 10 minutes.

The semiconductor wafer W is made 10 to 40 by the chemical solution.
If the removal rate decreases due to the decomposition of hydrogen peroxide after lot processing, it is recovered by adding new hydrogen peroxide, and when the removal rate decreases due to an increase in the concentration of organic substances dissolved in the chemical solution. Has adopted a method of exchanging with a new drug solution. It should be noted that N gas is introduced as an inert gas (not shown) into the chemical liquid to help prevent oxidation.

[0007]

However, such a processing method has the following drawbacks. a. The service life of the chemical solution is short with respect to the number of processed lots and the cost is high. B. When the chemical solution is near the end of its life, the organic substances attached to the semiconductor wafer W cannot be completely peeled off, and the stability of the peeling process is poor. c. Reverse contamination of the semiconductor wafer W to be processed is caused by the organic substances remaining in the chemical treatment, which adversely affects the electrical characteristics of the semiconductor element.

The present invention has been made under such circumstances, and in particular, it improves the efficiency of removing a resist adhering to a semiconductor wafer by a chemical solution and the processing of a wafer W for treating organic substances and preventing reverse contamination by organic impurities. .

[0009]

The method of treating a semiconductor wafer with a chemical solution according to the present invention is characterized in that the step of purging the mixed chemical solution for removing the organic substance coating the semiconductor wafer is performed.

Further, a processing tank for containing an organic substance removing chemical solution, a chemical solution supply mechanism connected to the processing tank, a purging material supply mechanism for inserting into the processing tank, and the purging material for inserting into the processing tank. The chemical liquid treatment apparatus for a semiconductor wafer according to the present invention is characterized by an opening formed in the supply mechanism, a heating unit arranged near the bottom of the processing tank, and an outlet formed in the bottom of the processing tank.

Furthermore, the present invention also provides a purging material circulation mechanism including an adsorption mechanism provided with an adsorbent for absorbing the purging material and a pipe for supplying the purging material purified by the adsorption mechanism to the chemical solution. There is a feature of the chemical liquid processing apparatus for such a semiconductor wafer.

[0012]

The present invention has been completed based on the finding that volatile organic substances can be efficiently volatilized by purging a mixed chemical liquid containing hydrogen peroxide etc. using, for example, helium (He) gas having a low solubility in water as a purging material. As a result, the chemical treatment yield of the semiconductor wafer is improved by about 5%.

[0013]

Embodiments of the present invention will be described with reference to FIGS. A mixed solution of hydrogen peroxide added to sulfuric acid is also used in the present invention as a chemical solution for removing organic impurities and resist adhered to a semiconductor wafer by a photolithography process or the like.

The structure of a processing apparatus 11 for containing a mixed chemical solution 10 for treating a semiconductor wafer with a chemical solution will be described with reference to FIG. The quartz processing tank 12 contains 13.5 liters of sulfuric acid and 1.5 parts of hydrogen peroxide as the mixed chemical liquid 10 for chemical liquid treatment.
Holds liters. A flow meter (not shown) is attached to the weighing tanks 13 and 14 for both liquids, and a drain 16 is formed in the bottom portion 15 of the quartz processing tank 12. Weighing tank 13, 14
Supply pipes 17 and 18 are installed between the quartz treatment tank 12 and the quartz treatment tank 12 to form a chemical solution supply mechanism.

Further, in the quartz processing tank 12, in addition to disposing the heating portion 19 on the bottom portion 15, a supporting portion 21 is installed on the side wall 20 to support the carrier 22 containing the semiconductor wafer W.
Further, a supply mechanism 23 for supplying, for example, helium gas, that is, a purging material, is installed in the quartz processing tank 12, and this also includes a quartz connecting portion 24 in which a flow meter (not shown) is installed. The quartz connecting portion 24 is composed of a portion 25 along the bottom portion 15 of the quartz processing tank 22 and an upright portion 26.
A plurality of openings 27 are installed in the portion 25 along the line 5, and a purging material such as helium gas in the form of bubbles is introduced into the quartz processing tank 12.

Further, an adsorbent for adsorbing the purging material, for example, activated carbon 29, is filled in the purging material circulating mechanism 28 connected to the purging material supply mechanism 23 by a quartz connecting portion 24, and adsorbed for purifying and passing. The trap 30 and the helium gas refining unit 30 'are attached. Furthermore, between the space formed on the liquid surface of the mixed chemical liquid 10 housed in the quartz processing tank 12 and the purging material circulation mechanism 28, the helium gas purification unit 3
0 ′ and the adsorption trap 30 are connected by pipes 31 and 32 to form a purging material supply mechanism 23.

The operation of the processing apparatus 11 for containing the mixed chemical solution 10 will be described. In the quartz processing tank 12, the mixed chemical solution 10 consisting of a predetermined amount of 13.5 liters of sulfuric acid and 1.5 liters of hydrogen peroxide and having a ratio of 1 is put from the weighing tanks 13 and 14. Next, the carrier 20 containing one lot of the semiconductor wafer W is placed on the support portion 21 and completely immersed. Next, the heating unit 19 is operated to mix the mixed chemical liquid 10 at 140 to 145 ° C.
Then, for example, helium gas is introduced as the purging material from the purging material supply mechanism 23. This is supplied from the purging material supply mechanism 23 at a temperature of 25 ° C. ± 2 ° C. and a flow rate of 0.1 liter / min.
It is introduced as fine bubbles through the portion 25 along the bottom 15 and the plurality of openings 27. 140-145 ° C
Carrier 20 containing one lot of semiconductor wafer W in the mixed chemical solution 10 for semiconductor wafer processing of about 10 minutes.
Is immersed to volatilize and peel off the coated organic substance, and at the same time, a fine bubble-like purging material is introduced to purge the semiconductor wafer processing mixed chemical solution 10.

The organic substances and helium gas vaporized from the mixed chemical liquid 10 for semiconductor wafer processing by such a purging process are recovered in the adsorption trap 30 'through the pipe 31 installed above the quartz processing tank 12, and, for example, by activated carbon 29. It is fed again to the purging material supply mechanism 23 via the purging material circulation mechanism 28 constituted by the post-purification pipe 32.

The mixed chemical liquid 10 for semiconductor wafer processing is discharged from the drain 16 after processing 100 lots of semiconductor wafer W and is replaced with a new mixed chemical liquid 10 for semiconductor wafer processing. Fine bubble-like purity is 99.9999%, 1.5Kg
Quartz glass was used for the portion 25 along the bottom portion 15 supplying the f / cm ² helium gas and the upright portion 26.

Such helium gas has a solubility in water at 30 ° C. of helium: 0.0084 and nitrogen: 0.0
Since it is lower than 1345 and nitrogen, the ratio of preventing the oxidation is large as compared with the inert gas used for preventing reoxidation, so that an extremely large purging effect can be exhibited. Further, as the adsorbent to be filled in the adsorption trap 30, in addition to activated carbon, there are Molecular Sieve and TANAX (trade name).
) Etc. can be used. In addition to sulfuric acid, the same method can be used for treatment with an alkali mixed solution of choline and hydrogen peroxide.

FIG. 2 shows the comparison between the present invention and nitrogen gas for preventing reoxidation, in which the removal rate is plotted on the vertical axis and the number of treatments is plotted on the horizontal axis. In addition, for example, helium gas, which not only prevents reoxidation but also exerts a purging effect, is improved by 5% from the yield when nitrogen is used for preventing reoxidation.

[0022]

EFFECTS OF THE INVENTION When a mixed chemical liquid for semiconductor wafer processing is subjected to a purging step using, for example, helium gas, the reaction is promoted by improving the circulation of the mixed chemical liquid that comes into contact with the semiconductor wafer, and the removal effect is further improved. Volatile organic substances are removed from the mixed chemical liquid to be cleaned. In addition, the life of the mixed chemical solution with respect to the number of processed lots can be extended from the conventional 40 lots to 100 lots, and a significant cost reduction can be achieved.

In addition, since the bubble-shaped purging material is evenly distributed in the mixed chemical liquid for semiconductor wafer processing, it is constantly purified, so that the removal effect can be kept constant until near its life (up to near replacement). it can. As described above, according to the present invention, volatile organic substances are removed from the mixed chemical liquid for semiconductor wafer processing, and at the same time, reverse contamination of the semiconductor wafer can be prevented, so that deterioration of the electrical characteristics of the semiconductor element can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a mixed chemical liquid processing apparatus for semiconductor wafer processing of the present invention.

FIG. 2 is a curve diagram showing a comparison between the method of the present invention and the case where nitrogen gas for preventing reoxidation is used, in which the removal rate is plotted on the vertical axis and the number of treatments is plotted on the horizontal axis.

FIG. 3 is a diagram showing an outline of a conventional chemical liquid processing apparatus.

[Explanation of symbols]

 10: Chemical liquid for semiconductor processing, 11, 50: Processing device, 12, 51: Processing tank, 13, 14, 52, 53: Weighing tank, 15: Bottom part, 16, 54: Drain, 17, 18: Supply pipe, 19 , 55: heating part, 22, 56: carrier, 21, 57: support part, 20, 58: side wall, 23: purging material supply mechanism, 24: quartz connection part, 25: part along bottom part, 26: Upright portion, 27: Opening, 28: Purging material circulation mechanism, 29: Activated carbon, 30: Adsorption trap, 30 ': Helium gas refining section, 31, 32: Piping.

Claims (3)

[Claims] 1. A method for treating a semiconductor wafer with a chemical liquid, comprising the step of purging a mixed chemical liquid for removing an organic substance coating the semiconductor wafer. 2. A treatment tank containing a chemical for removing organic substances,
A chemical solution supply mechanism connected to this, a purging material supply mechanism to be inserted into the processing tank, an opening formed in the purging material supply mechanism to be inserted into the processing tank, and a portion disposed near the bottom of the processing tank. And a discharge port formed at the bottom of the processing tank. 3. A purging material circulation mechanism comprising an adsorption mechanism provided with an adsorbent for absorbing the purging material and a pipe for supplying the purging material purified by the adsorption mechanism to the chemical liquid. The chemical treatment apparatus for semiconductor wafer according to claim 2, wherein