JPH03121186A - Agent for polishing surface of hard and brittle material - Google Patents

Abstract

PURPOSE:To obtain the title polishing agent which can minimize an adverse effect on the working environment, can reduce the corrosion of a polishing device, and is improved in the polishing action on a surface of a hard and brittle material, handleability, etc., by dissolving a specified halogenated organic nitrogen compound in an organic solvent. CONSTITUTION:An organonitrogen halide compound of the formula (wherein R<1> to R<4> are each an organic group; X is Cl or Br) (e.g. polybrominated stearylbenzyldimethylammonium) is dissolved in an organic solvent (e.g. methanol) and, if necessary, the obtained solution is mixed with 0.5-7% fine hard particles insoluble therein (e.g. precipitated silica) having a mean particle diameter of 0.01-10mum to give the title polishing agent. A hard and brittle material comprising a semiconductor crystal of a compound such as GaAs, GaP or InP is polished in a polishing device by using the polishing agent.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a polishing agent for solid surfaces, particularly compound semiconductor crystals such as GaAs (gallium arsenide), GaP (gallium phosphide) and InP (indium phosphide). The present invention relates to a chemical polishing agent or a mechanochemical polishing agent for polishing hard and brittle materials such as those with high efficiency to a non-irregular mirror surface.

(Prior Art) Conventionally, in the polishing of chemical semiconductor crystal substrates such as GaAs, GaP, and InP, the surface is usually polished using a polishing device such as a ring polisher while dropping an abrasive to an appropriate polishing pressure. In order to ensure high polishing efficiency and a precise mirror finish on the processed surface, oxidation and dissolution using an aqueous solution of inorganic oxidizing substances such as chlorine ((:JZz) and bromine (Brz)), which have an etching effect, are performed. It is known that a mixed solution of bromine and methanol is used as an abrasive.

With these methods, excellent polishing performance has been obtained through selection of composition, concentration, and processing technology.

(Problems to be Solved by the Invention) However, in the conventional polishing technology, there are problems such as the instability of the chemicals and the problem of corrosion depending on the material of the equipment used for processing. In addition, there was a problem in that it was a burden to take measures to improve the working environment, as there was a risk that the processing atmosphere would have an adverse effect on the human body.

For example, when a mixed solution of bromine and methanol is used as the above-mentioned polishing agent, the prepared mixed solution of the polishing agent decomposes shortly after preparation, so it is necessary to prepare the solution each time polishing work is performed, which is a problem in work efficiency. There is a problem.

In addition, this abrasive solution inevitably generates bromine gas, albeit in a small amount, so in actual industrial equipment, we take into account the working environment where bromine gas, which is toxic and irritating to the human body, is used. It is necessary to install equipment that takes gas sealing measures and exhaust into consideration. Moreover, since bromine gas has a strong effect of corroding metals, the materials that can be used to construct polishing equipment are limited. It is not easy to satisfy the requirements for material selection at the same time, and there have been problems such as increased equipment costs, decreased equipment durability, and shortened lifespan.

(Means for Solving the Problems) The present invention solves the problems of conventional abrasives as described above,
It has an excellent effect as a surface abrasive for hard and brittle materials, is easy to handle, has little negative impact on the working environment, and is free by reducing corrosivity to the materials that make up the equipment as much as possible. The purpose of this invention is to provide a novel surface abrasive for hard and brittle materials that allows for a wide selection of materials for equipment used and allows the construction of highly durable equipment.

Another object of the present invention is to provide an abrasive that is stable as an abrasive and does not require preparation immediately before use unlike conventional abrasives, and therefore enables efficient design of polishing work procedures. It's there.

The characteristics of the surface abrasive for hard and brittle materials according to the present invention, which has been made to achieve the above object, are as follows, for example: Formula (I)
Quaternary ammonium polyhalides represented by R'R'' R3 R'N''
is chlorine or bromine) or halogenated carboxylic acid imide (R-CO) iNX represented by the following formula (II)... (II) (
However, R is an alkylene group and X is chlorine or bromine).

The active ingredient is Also, in this abrasive,
An example of a particularly effective abrasive having a mechanochemical action is an abrasive containing hard fine particles that do not dissolve in the organic solution. In this case, these hard particles are 0
．． In many cases, it is appropriate to include particles having an average particle diameter of about 0.01 to 10 μm in an amount of about 0.5 to 7% in the polishing liquid.

Examples of organic solvents that dissolve these organic nitrogen halides include methanol, ethanol, ethylene glycol, acetone, methylene chloride, carbon tetrachloride, and benzene.

In the above, for example, in order to produce polybrominated products of quaternary ammonium, a chlorine salt or a bromine salt of quaternary ammonium (RI R2R3R4N") M, where R',
It can be obtained by reacting R2, R3, R' XLt (same as above) with sodium bromite (NaBr02). That is, a chlorine salt (or bromine salt) of quaternary ammonium is dissolved in alkaline water, an aqueous solution of sodium bromite is added thereto, and an inorganic or organic acid is added to make the polybrominated quaternary ammonium acidic. The ammonium salt is produced as a precipitate, and this precipitate is separated.
A pure polybrominated quaternary ammonium salt can be obtained by washing or the like. The polybrominated quaternary ammonium salt can also be obtained by reacting the chlorine or bromine salt of the quaternary ammonium with bromine or a compound that generates free bromine in an acidic solution in a liquid phase. Specifically, quaternary ammonium chlorine or bromine salts used in the method include those that are generally commercially available as reagents or surfactants, such as stearylbenzyldimethylammonium halide salt, benzyltrimethylammonium halide salt, and tetrabutylammonium halide. Examples include salt and the like.

On the other hand, specific examples of the halogenated carboxylic acid imides include N-bromosuccinimide, etc., and depending on the type of workpiece, degree of processing, etc.
- Numerically, it is often appropriate to prepare a polishing liquid by dissolving this in the above-mentioned organic solvent in a range of about 0.2 to 5% by weight.

Hard and brittle materials to which the abrasive of the present invention is applied typically include the above-mentioned GaAs and GaP.

An example is InP, but the material is not particularly limited thereto.

(Effects of the Invention) By having the above structure, the abrasive of the present invention exhibits an excellent effect as an abrasive for hard and brittle materials like conventional abrasives, is harmless to the human body, and is stable. It has the advantage of being able to perform polishing work with high quality and high efficiency, and is particularly effective in polishing the surface of hard and brittle materials such as compound semiconductor crystals such as GaAs, GaP, and InP.

(Example) Examples of the preparation method of the abrasive and the polishing method using the abrasive of the present invention will be described below, but the above and other problems and novel features of the present invention will become clearer from the following explanation. Will.

Example 1 Stearylbenzyldimethylammonium chloride C
Cl8H37C7Ht(CHs)2N"Cl1-, trade name Sanisol B-50. Manufactured by Kao Corporation] purity 0.5 m
ail (212g) was dissolved in water 300a + JZ, and 1.5 mail (I20g> industrial bromine (manufactured by Tosoh Corporation) was dissolved in 700nl of strength soda with a concentration of 10%, and the total amount of both solutions was brought to room temperature. The mixed solution had no precipitates, was homogeneous, and had an alkaline pH of 13.8.

While stirring this solution, a 20% acetic acid aqueous solution was gradually added to lower the pH, and a yellowish brown precipitate was formed at pH 11-9. Further, an acetic acid solution was added to lower the pH to 4, and the precipitate was then filtered, washed with water, kept at 50° C., and dried in a drier to obtain a polybrominated quaternary ammonium salt. 310 g of polybrominated stearylbenzyldimethylammonium (hereinafter abbreviated as "r5BDA-nBr") was obtained.

It is an odorless tan solid with 38% reactively bound bromine.
It melts at about 50°C, is insoluble in water, but soluble in alkaline water with a pH of 10.5 or higher, such as caustic soda, and soluble in organic solvents such as methanol, ethanol, and methylene chloride. It can also be stored for long periods at room temperature.
No alteration 1 decomposition was observed.

Preparation of polishing liquid The SBD-nBr obtained above was dissolved in methanol to a concentration of 2.7% (Test No. 1) as shown in Table 1 below.

A 1.4% (Test No. 2) polishing liquid was prepared. In addition, SBD with a concentration of 0.7% was used instead of ethanol as the organic solvent.
A ^-nBr polishing liquid (Test No. 3) was prepared.

Furthermore, the polishing liquid of (Test No. 2) had an average particle size of 1.3.
A slurry-like polishing slurry liquid (Test No. 4) was prepared by containing 3.5% of μm precipitated silica "Nip Seal E-743J (manufactured by Nippon Silikani Gyo Co., Ltd.).

Polishing thickness 0.7+nmLf)G a As single crystal substrate 1
Cut into 5 mm squares and use adhesive plates with a diameter of 100 mm (7
50g), three sheets were glued at equal intervals. Also, the surface plate (
A polyurethane-impregnated polyester nonwoven fabric volisher (diameter: 300 mm) was applied to the volister, and the adhesive plate was placed on the volisher.

Next, while dropping each polishing liquid, the polishing was performed using a modified wheel type polisher at a surface plate rotation speed of 60 rpm and a polishing pressure of 107 g/clQ.
2. The above GaAs substrate was polished for 30 minutes under the condition that the polishing liquid supply amount was in/hr.

The concentration and composition of the polishing liquid, the polishing conditions, and the condition of the polished surface obtained as a result of polishing are summarized in Table 1 below.

In addition, in the same manner as above, a polishing liquid (test No. 5) was prepared using polybrominated tetrabutylammonium (hereinafter abbreviated as rTBA-nBrj) produced as follows, and a polishing test was conducted in the same manner as above. The results are shown in Table 1 below.

r Production of TBA-nor ``Tetrabutylammonium bromide [C4H9)4
N” Br-; reagent manufactured by Kishida Chemical Co., Ltd.] 64 g (0.2 m
of ), 35 g of sodium bromide (NaBr; reagent manufactured by Kanto Kagaku Co., Ltd.), and 10 g of sodium bromate (NaBros; reagent manufactured by Kanto Kagaku Co., Ltd.) were dissolved in 200 ml of a caustic soda aqueous solution adjusted to pH 13, and 1 ml of acetic acid was added with stirring at room temperature.
A 0% aqueous solution was gradually added dropwise. A brown precipitate was formed when the pH decreased to 10 to 9, and an acetic acid aqueous solution was further added to lower the pH to 3 to complete the reaction. 100 mft of methylene chloride was added to this suspension, the suspension was dissolved in methylene chloride, and the aqueous layer was separated. After washing the methylene chloride solution with water, the methylene chloride was distilled off by heating to 50° C. to obtain 92 g of “rTBA-nBr” as a product.

As a result of analysis, this substance contained 47% of bound bromine, was insoluble in water, but soluble in alkaline aqueous solutions and organic solvents with a pH of 10.5 or more, and did not change in quality as long as it was stored at room temperature.

Table 1 As is clear from the results shown in Table 1, in each of the examples of the present invention, no irritating gas was generated during the polishing process, there was no fear of corrosion of the metal materials of the equipment, and the results were extremely
I was able to perform gentle machining work. Regarding polishing performance, the polishing speed was faster and the polished surface after polishing was of high quality compared to conventional aqueous solution type polishing agents. Furthermore, it was confirmed that the quality of the abrasive was improved by the combined use of particulate matter, and a polishing state superior to that of commonly used abrasives was obtained.

Example 2 N-bromosuccinimide (
Commercial reagent; Kanto Kagaku Co., Ltd.) (hereinafter abbreviated as rNBsJ), N-chlorosuccinimide (commercial reagent; Kanto Kagaku Co., Ltd.) (hereinafter abbreviated as rNcsJ), N-bromomethylphthalimide (commercial reagent; Kanto Kagaku Co., Ltd.) (manufactured by rNB) (hereinafter referred to as rNB
(abbreviated as MPJ) is used for each of the methods shown in Table 2.
A polishing liquid was prepared by dissolving it in a solvent.

Polishing The GaAs single crystal substrate was polished under the same conditions as in Example 1, and the results are shown in Table 2 below.

Table 2 As is clear from the results in Table 2, N-bromosuccinimide (NBS) has a major feature of high polishing efficiency (polishing speed), so it can achieve a predetermined polishing amount in a short time. There is an effect that a sufficient amount of polishing can be secured with a dilute concentration, and a good polished surface can be obtained.

In addition, N-chlorosuccinimide (NCS) is the above-mentioned (N
Although the polishing efficiency is lower than that of (BS), the condition of the polished surface is superior to that of (NBS).

Furthermore, when hard Jit fine particles insoluble in the solvent are contained, the quality of the polished surface can be significantly improved depending on the selection of the fine particles.

Example 3 Polishing was carried out in the same manner as in Example 1 except that a GaP single crystal substrate and an InP single crystal substrate were used instead of the GaAs polishing agent used in Example 1.

As a result, it was confirmed that a polishing rate similar to that of GaAs and a high-quality polished surface could be obtained.

Example 4 Instead of precipitated silica in test No. 4 of Example 1,
When polishing was carried out in the same manner as in Example 1 by adding fine particles of calcium carbonate, chromium oxide, alumina, and silicon carbide to the polishing liquid, it was confirmed that similar polishing speeds and high-quality polished surfaces could be obtained. . It was confirmed that the more uniform the diameter of the hard particles contained in the polishing liquid, the higher the quality of the polished surface.

Procedural amendment dated 1995/1995/3E (1. Table of cases/I- 1999 ↑ Sea ↑ Petition No. 2 &!; ΔZ No. 4, Agent address: 2-6-2 Marunouchi, Chiyoda-ku, Tokyo Shigesu Building 330 and 4 others to Marunouchi 7.Amendment t.t.$ Amendment The following matters will be amended in the specification of the application.

Record 1. On the second page, second line. It says "methyl chloride," "Methylene chloride," I corrected.

2. On page 12, lines 9-10, '[C4He) 4N'Br-J and Aruwo' [(C
4H9) Correct as J”Br-”.

3, page 17, line 8 It says "those of uniform diameter" Correct it to "a homogeneous thing."

Claims (1)

[Scope of Claims] 1. A surface abrasive for hard and brittle materials R^1R^2R^3R^4N, characterized by comprising an organic solvent solution in which an organic nitrogen halogen compound represented by the following general formula (I) is dissolved. ＾＋X＾−＿n・・・・・・
(I) (However, R^1, R^2, R^3, and R^4 are organic groups and may be the same or different.
is chlorine or bromine). 2. Surface abrasive for hard and brittle materials (R-CO)_2NX (II), characterized by being composed of an organic solvent solution in which a halogenated carboxylic acid imide represented by the following general formula (II) is dissolved (However, R is an alkylene group and X is chlorine or bromine)
. 3. In claim 1 or 2, the organic solvent is methanol,
A surface abrasive for hard and brittle materials characterized by being one of ethanol, ethylene glycol, acetone, methyl chloride, carbon tetrachloride, and benzene. 4. A surface abrasive for hard and brittle materials according to any one of claims 1 to 3, characterized in that it contains hard fine particles that do not dissolve in the organic solution. 5. In any one of claims 1 to 4, the hard brittle material is G.
A surface abrasive for hard and brittle materials, characterized in that it is aAs, GaP, or InP.