WO2014162945A1 - Water soluble cutting fluid for fixed abrasive grain wire saw, ingot cutting method using same, and substrate for electronic material obtained by means of same - Google Patents

Abstract

Provided are a water soluble cutting fluid for a fixed abrasive grain wire saw that has little foaming and high cutting performance, an ingot cutting method using the same, and a substrate for electronic material obtained by means of the same. The water soluble cutting fluid for a fixed abrasive grain wire saw is characterized by containing (a) an alkylene adduct of 2,4,7,9-tetramethyl-5-decyne-4,7-diol as shown in chemical formula (1). Also provided are an ingot cutting method characterized by cutting an ingot by means of the fixed abrasive grain wire saw using the water soluble cutting fluid for a fixed abrasive grain wire saw and obtaining wafers that are electronic material substrates as well as a substrate for electronic material obtained by this cutting method.

Description

Water-soluble cutting liquid for fixed abrasive wire saw, ingot cutting method using the same, and substrate for electronic material obtained thereby

The present invention relates to a water-soluble cutting solution for a fixed abrasive wire saw used for cutting a silicon ingot, an ingot cutting method using the same, and an electronic material substrate obtained thereby.

Conventionally, wafers for substrates for electronic materials have been obtained by cutting with a band saw or wire saw using loose abrasive grains. However, when cutting with loose abrasive grains, slurry adheres to the cut wafer, and the cleaning load in the subsequent process is high. Also, it is difficult to separate loose abrasive grains, sludge, and cutting liquid from the working liquid, and recycling There is a problem that the nature is bad.

In response to these problems, a fixed-abrasive wire saw in which abrasive particles are fixed to the wire using electrodeposition or resin bond has been developed, and the recyclability is improved by simplifying the cleaning process and separating the cutting fluid and sludge. Has the advantage of As cutting fluid used when cutting the wafer which is a substrate for electronic materials using this fixed abrasive wire saw, water and water-soluble cutting fluid are proposed in patent documents 1 and 2, for example.

JP 2003-82334 A JP 2009-57423 A

However, in recent years, the wire speed has been increased in order to improve quality and cutting speed, and an ingot that becomes a substrate for electronic materials is cut using a water-soluble cutting liquid as disclosed in Patent Documents 1 and 2. Then, there is a problem that the water-soluble cutting liquid used is foamed and a wafer with good quality cannot be obtained.

Therefore, the present invention provides a water-soluble cutting solution for a fixed abrasive wire saw with less foaming and high cutting performance, an ingot cutting method using the same, and a substrate for electronic materials obtained thereby.

In order to achieve the above object, the present inventors have conducted extensive research and, as a result, (a) an alkylene adduct of 2,4,7,9-tetramethyl-5-decyne-4,7-diol has been obtained. By using the water-soluble cutting liquid contained, it was found that even when used for a fixed abrasive wire saw, it is possible to cut with less foaming and high cutting performance, and the present invention has been achieved. That is, the present invention contains an alkylene adduct of (a) 2,4,7,9-tetramethyl-5-decyne-4,7-diol represented by the following chemical formula (1): The present invention relates to a water-soluble cutting liquid for abrasive wire saws.

（ただし、Ｒはそれぞれ同一または異なる炭素数１～４のアルキレン基を示し、ｍ１＋ｍ２＋ｎ１＋ｎ２はアルキレン付加物の総付加モル数を示し、１以上の整数である。）

(However, R represents the same or different alkylene group having 1 to 4 carbon atoms, and m1 + m2 + n1 + n2 represents the total number of added moles of the alkylene adduct and is an integer of 1 or more.)

Further, the present invention provides an ingot cutting method characterized in that a wafer which is a substrate for electronic materials is obtained by cutting an ingot with a fixed abrasive wire saw using the water-soluble cutting liquid for fixed abrasive wire saw, and The present invention relates to an electronic material substrate obtained by the cutting method.

As described above, according to the present invention, there are provided a water-soluble cutting solution for a fixed abrasive wire saw with low foaming and high cutting performance, a method for cutting an ingot using the same, and a substrate for electronic materials obtained thereby. I can do it.

The alkylene adduct of 2,4,7,9-tetramethyl-5-decyne-4,7-diol as component (a) used in the water-soluble cutting solution for fixed abrasive wire saws according to the present invention has the following chemical formula: It has the structure shown by (1).

（ただし、Ｒはそれぞれ同一または異なる炭素数１～４のアルキレン基を示し、ｍ１＋ｍ２＋ｎ１＋ｎ２はアルキレン付加物の総付加モル数を示し、１以上の整数である。）

(However, R represents the same or different alkylene group having 1 to 4 carbon atoms, and m1 + m2 + n1 + n2 represents the total number of added moles of the alkylene adduct and is an integer of 1 or more.)

In the above chemical formula (1), the alkylene oxide added to 2,4,7,9-tetramethyl-5-decyne-4,7-diol may be any alkylene oxide having 1 to 4 carbon atoms. Specifically, ethylene oxide alone or both ethylene oxide and propylene oxide are particularly preferable.
In addition, since the alkylene oxide to be added is added by random polymerization, the four alkylene groups (—OR—) in the chemical formula (1) are the same as long as each is an alkylene group having 1 to 4 carbon atoms. Although it may be present or different, it is preferred that the four alkylene groups are either ethylene alone or both ethylene and propylene, and it is particularly preferred that all four alkylene groups are ethylene.
In the chemical formula (1), the total number of added moles of the alkylene adduct is 1 mole or more, preferably 1 to 20 moles, and more preferably 4 to 12 moles. In particular, when the added alkylene adduct is an ethylene oxide simple substance, 4 to 12 mol of ethylene oxide is preferable, 4 to 8 mol is more preferable, and 4 to 6 mol is particularly preferable. Further, when the added alkylene adduct is ethylene oxide or propylene oxide, 4 to 8 mol of ethylene oxide and 2 to 4 mol of propylene oxide are preferable.

As the component (a), one type may be used alone, or two or more types may be used in combination. The amount of the component (a) to be added is 0.01 to 5.0% by weight with respect to the water-soluble cutting solution. % Is preferable, and 0.05 to 2.0% by weight is more preferable. When the added amount of (a) is less than 0.01% by weight, the defoaming effect is small, and the dynamic surface tension of the water-soluble cutting liquid is high, so that the water-soluble cutting liquid is difficult to enter the processing point and tends to deteriorate the cutting quality. When the amount exceeds 5.0% by weight, it may be difficult to achieve a blending balance in which the water-soluble cutting liquid exhibits a defoaming effect.

The water-soluble cutting liquid for fixed abrasive wire saws according to the present invention preferably contains the following components (b), (c) and (d) in addition to the component (a). By including the components (b), (c) and (d), the lubricity between the fixed abrasive wire and the workpiece can be controlled, and the tool life of the fixed abrasive wire is improved.

In the present invention, the component (b) is preferably at least one of carboxylic acid, mercaptobenzothiazole, benzothiazolylthioacetic acid and benzothiazolylthiopropionic acid. The carboxylic acid only needs to have one or more COOH groups. For example, caprylic acid, caproic acid, lauric acid, oleic acid, citric acid, maleic acid, fumaric acid, adipic acid, isophthalic acid, malic acid, Examples include tartaric acid, dodecanedioic acid, and sebacic acid. (B) A component can be used individually by 1 type and can also use 2 or more types together.

The component (c) is preferably at least one of amine, sodium hydroxide and potassium hydroxide, more preferably an amine. Examples of amines include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, dicyclohexylamine, trimethylolpropane poly (oxypropylene) triamine, N, N-bis (2hydroxyethyl)- Examples include alkylene adducts of N-cyclohexylamine and metaxylenediamine. As the component (c), one type may be used alone, or two or more types may be used in combination.

The component (b) and the component (c) can be contained in any ratio as long as they are soluble in water. Preferably, the component (c) is neutralized or more than the component (b). The total sum of the component (b) and the component (c) is desirably 5% by weight or less.

In addition, the component (d) is preferably at least one of glycol, polyalkylene glycol, glycol ether, polyalkylene glycol ether, glycerin and an alkylene adduct of glycerin. The glycol only needs to have two OH groups, and examples include monoethylene glycol, diethylene glycol, triethylene glycol, monopropylene glycol, dipropylene glycol, tripropylene glycol, and hexylene glycol. Examples thereof include polyethylene glycol, polypropylene glycol, polyoxyethylene polyoxypropylene copolymer, and polyoxyethylene polyoxybutylene copolymer. Examples of the glycol ether include diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, and diethylene glycol monohexyl ether. Examples of the polyoxyalkylene glycol ether include polyoxyethylene monomethyl ether, polyoxypropylene monomethyl ether, and monobutyl ether of a polyoxyethylene polyoxypropylene copolymer. Examples of the alkylene adduct of glycerin include ethylene adduct, propylene adduct and ethylene propylene copolymer adduct of glycerin. As the component (d), one type may be used alone, or two or more types may be used in combination. Although content of (d) component should just be soluble in water, Preferably it is 70 weight% or less.

Moreover, the water-soluble cutting liquid for fixed abrasive wire saws according to the present invention may contain a rust preventive, preservative, fragrance, dye or the like, if necessary.

The substrate for electronic materials with good quality can be obtained by cutting the ingot with a fixed abrasive wire saw using the water-soluble cutting solution for fixed abrasive wire saw according to the present invention.

In the fixed abrasive wire saw used in the present invention, the wire serving as the bus bar may be made of iron or stainless steel, copper-plated or platinum-plated. As the abrasive grains fixed to the wire, commercially available abrasive grains can be used, but diamond and boron nitride are preferred. In order to fix the abrasive grains to the wire, electrodeposition using a metal such as nickel or resin bonding using a resin is preferable.

Further, the cutting machine used in the present invention is not particularly limited as long as it is a commercially available multi-wire saw machine, and a multi-wire saw machine dedicated to a fixed abrasive wire saw is preferable.

The ingot used in the present invention is not particularly limited as long as it is an ingot manufactured for an electronic material substrate. For example, silicon, sapphire, crystal, quartz, silicon carbide, lithium tantalate, gallium nitride, and gallium arsenide An ingot having a high purity obtained by crystal growth or the like is preferably used.

As described above, when cutting a wafer which is a substrate for electronic materials from an ingot with a fixed abrasive wire saw, by using the water-soluble cutting liquid for fixed abrasive wire saw according to the present invention, there is less foaming and cutting The performance can be improved.

Next, examples of the water-soluble cutting solution for fixed abrasive wire saw according to the present invention will be described, but the present invention is not limited thereto. First, according to the compounding quantity of each component shown in Table 1 and Table 2, these are mixed by a conventional method, The water-soluble cutting liquid for fixed abrasive wire saws which concern on Example 1 thru | or Example 9, and Comparative Example 1 thru | or A water-soluble cutting liquid for a fixed abrasive wire saw according to Comparative Example 4 was obtained.

(Bubbling test)
Next, assuming foaming during cutting, the water-soluble cutting liquid for fixed abrasive wire saws according to Examples 1 to 9 and the water-soluble cutting liquid for fixed abrasive wire saws according to Comparative Examples 1 to 4 Was put into a stoppered 100 ml graduated cylinder, sealed, and shaken vigorously, and the initial foaming amount immediately after that and the defoaming time until foaming disappeared were confirmed. The results are shown in Table 3. In addition, the stability is left at 25 ° C. for 1 week, ○: no separation / precipitation for 1 week, Δ: separation / precipitation occurs in 4 days or more, less than 1 week, ×: separation / precipitation occurs in less than 4 days did.

From Table 3, it can be seen that the cutting liquid of Comparative Example 2 has poor stability, and the cutting liquids of Comparative Examples 3 and 4 have much foaming and the defoaming time has exceeded 60 seconds. On the other hand, it turns out that the water-soluble cutting liquid for fixed-abrasive wire saws according to the present invention is good with less foaming. In Comparative Example 2 with poor stability, the separated component (a) adheres to the apparatus and piping, causing contamination, and the cutting quality deteriorates due to removal of the component (a) from the cutting fluid. It is difficult to use as a liquid.

(Cutting test)
Next, using the water-soluble cutting solution for fixed abrasive wire saws according to Examples 1 to 9 and the water-soluble cutting solution for fixed abrasive wire saws according to Comparative Examples 1 to 4, cutting was performed under the conditions shown in Table 4. A test was performed and the maximum valley height (PV) of the cross-sectional curve of the cut wafer was measured. The results are shown in Table 5.

From Table 5, it can be seen that the ingots cannot be cut with the cutting fluids of Comparative Examples 1 and 2, and the cutting fluids of Comparative Examples 3 and 4 have a large PV value and cannot form a good cross section. On the other hand, it can be seen that the water-soluble cutting liquid for fixed abrasive wire saws according to this example has a small PV value and good cutting performance.

Claims (7)

Water-soluble for fixed-abrasive wire saw characterized by containing an alkylene adduct of (a) 2,4,7,9-tetramethyl-5-decyne-4,7-diol represented by the following chemical formula (1) Cutting fluid.

(However, R represents the same or different alkylene group having 1 to 4 carbon atoms, and m1 + m2 + n1 + n2 represents the total number of added moles of the alkylene adduct and is an integer of 1 or more.) The water-soluble cutting solution for a fixed abrasive wire saw according to claim 1, wherein the total number of added moles of the alkylene adduct (a) is 4 to 12 moles. The water-soluble cutting solution for a fixed abrasive wire saw according to claim 1 or 2, wherein the content of (a) is 0.01 to 5.0% by weight. And (b) at least one or more of carboxylic acid, mercaptobenzothiazole, benzothiazolylthioacetic acid and benzothiazolylthiopropionic acid, and (c) at least one or more of amine, sodium hydroxide and potassium hydroxide. The water-soluble cutting liquid for fixed abrasive wire saws according to any one of claims 1 to 3, which is contained. The fixed abrasive according to any one of claims 1 to 4, further comprising (d) at least one of glycol, polyalkylene glycol, glycol ether, polyalkylene glycol ether, glycerin and an alkylene adduct of glycerin. Water-soluble cutting solution for grain wire saws. A method for cutting an ingot, characterized in that the substrate for electronic materials is obtained by cutting the ingot with a fixed abrasive wire saw using the water-soluble cutting solution for fixed abrasive wire saw according to any one of claims 1 to 5. An electronic material substrate obtained by the ingot cutting method according to claim 6.