WO2012016976A1 - Carrier fluids for abrasives - Google Patents

Abstract

The invention relates to improved novel carrier fluids for abrasives, especially cutting fluids, for wafer production. The invention also relates to the use of said fluids and to a method for cutting wafers.

Description

 Carrier fluids for abrasives

The invention relates to the use of modified polyglycols for the production of carrier liquids for abrasives, new carrier liquids for abrasives, in particular cutting fluids, the use of the carrier liquid in the removal of material, in particular when cutting wafers, and wafers produced with the aid of the cutting fluid.

Abrasives, also called abrasives or abrasives, are substances, preferably hard-material grains, which are used for the removal of a material. It is known to use abrasives as a dispersion in liquids, for example grinding or cutting fluids. Abrasives can be used in this way for polishing wafers, for example made of silicon, but also for polishing plastics, for example for lenses. It is also known to use abrasives in cutting fluids for cutting wafers. Wafers are thin slices of semiconductors that are used, for example, in photovoltaic. From wafers electronic components, especially integrated circuits can be produced. The wafers are usually made of brittle material, such as silicon, but also of gallium arsenide or cadmium telluride, etc. Basis for the wafer production are usually cylindrical or cubic single or polycrystals, which are sawed into the individual slices, the wafer. Sawing (also referred to as cutting or lapping) is done in practice by wire sawing. This is a separation process using a thin wire as a cutting edge and using unbound cutting grains in a carrier liquid. The wire usually has a diameter of 80 to 180 μηι. He immersed in a slurry of carrier liquid and cutting grain and pulls the hanging on the wire surface cutting grains in the kerf. The cutting grains are used to cut the object to be sawn / lapped / silicon ingots into wafers, with particles being removed from the solid to be cut. The carrier liquid for the cutting grains is applied as a slurry via a dipping bath, through which the wire runs, as well as generally via nozzles together with the cutting grain. Among other things, the carrier liquid has the task of ensuring that the cutting grains adhere to the wire and removing removed particles from the solid to be broken up. Furthermore, the carrier liquid has the task to provide for cooling and the transport of the abrasion through the Sägeschlitz.

From EP 1 757 419 A1 a method for separating a workpiece, for example a wafer, by means of wire saws is already known, one on the wire applied slurry is used and the water content of at least a portion of the slurry surrounded gaseous medium is regulated or controlled. It is further known from EP 1 757 419 A1 to use glycols as the carrier substance. DE 199 83 092 B4 and US Pat. No. 6,383,991 B1 disclose a cutting oil comprising a) a polyether compound and b) silica particles, and the use of this cutting oil composition for cutting a billet using a wire saw, in particular for cutting silicon ingots. EP 0 131 657 A1 and US Pat. No. 4,828,735 disclose water-based lubricants based on polyethers. From the Chinese patent application CN 101205498 A cutting fluids are also known, while a reduction in water absorption is not specified. The compounds specifically mentioned are polyalkyleneoxy compounds etherified with alcohols having 1 to 4 carbon atoms.

From EP 686 684 A1, a sawing suspension consisting of an abrasive in an aqueous phase is known which contains one or more water-soluble polymers as thickener. US 2007/0010406 A1 discloses hydroxypolyethers as additives for aqueous cutting fluids which can be used inter alia for the production of silicon wafers.

The known cutting fluids are generally based on an aqueous or a water-soluble basis. However, the presence of water is disadvantageous because it both causes corrosion and, for example, when cutting silicon wafers by reaction of water and silicon hydrogen evolution can take place. In this case, there is the additional problem that there is a silicate or polysilicate formation on the wafer and in the slurry. The known water-soluble systems can also contain water and, because of their microscopic properties, attract water, so that the same disadvantages can occur as with aqueous systems.

The object of the invention was to provide improved carrier fluids for abrasives, in particular cutting fluids, which in particular lead to a reduction in water absorption and a reduction in the energy required for sawing.

The invention relates to the use of compounds of the formula I. R ¹ [O (EO) _x (AO) _y H] _z in which R is a z-valent alkyl radical having 1 to 20 C atoms

 (EO) ethyleneoxy radical

 (AO) Alkyleneoxy radical having 3 to 10 C atoms

 x is a number from 3 to 12, in particular 5 to 10

 y is a number from 0 to 10, in particular 4 to 8

 z is a number from 1 to 6, in particular 1 to 3 for the production of carrier liquids for abrasives, in particular cutting fluids with reduced water absorption for removing material, in particular for sawing wafers with a wire saw.

The invention further relates to carrier liquids for abrasives, in particular cutting fluids, containing at least one compound of the formula I.

R ¹ [O (EO) _x (AO) _y H] _z in which

R is a z-valent alkyl radical having 5 to 10 carbon atoms

 (EO) ethyleneoxy radical

 (AO) Alkyleneoxy radical having 3 to 10 C atoms

 x is a number from 3 to 12, in particular 5 to 10

 y is a number from 0.5 to 10, in particular 4 to 8

 z is a number from 1 to 6, in particular 1 to 3. The invention further relates to novel compounds II of the formula

R ¹ O (EO) _x (AO) _y H where

R ^{1 is} 2-methylbutyl or 3-methylbutyl

 (EO) ethyleneoxy radical

 (AO) Alkyleneoxy radical having 3 to 10 C atoms

 x is a number from 3 to 12, in particular 5 to 10

 y is a number from 0 to 10, in particular 4 to 8

z is a number from 1 to 6, in particular 1 to 3 In preferred compounds of the formula II, at least as many EO units as PO units are present. Very particularly preferred compounds of the formula II are given in the following table:

 In a preferred embodiment, the ratio x to y in the compound of the formula I and II is equal to or less than 1. In the context of the present invention, compounds of the formula II are particularly preferred embodiments of compounds of the formula I.

In a preferred embodiment, in formula I: R ^{1 is} pentyl, preferably

 H3C-CHCH3-CH2-CH2- (3-methylbutyl) and

H ₃ C-CH ₂ -CHCH ₃ -CH ₂ - (2-methylbutyl), in particular at least 10% 3-methylbutyl- in formulas I and II: AO propyleneoxy, butyleneoxy and pentyleneoxy or mixtures thereof.

In the case of the compounds of the formulas I and II, the recurring units (EO) and (AO) can be present as a block or randomly distributed (random). In a preferred embodiment, they are statistically distributed. Surprisingly, it has been found that in the case of statistical distribution of the recurring units (AO) and (EO), the viscosity of the compounds is largely independent of temperature. Particularly in the case of statistical distribution of the recurring units (EO) and (AO), the compounds of the formula I to be used according to the invention are distinguished by a viscosity index in a slurry with 40% by weight of Carborex F 800 PV silicon carbide from Washington Mills AS, NO -7300 Orkanger, Norway, of not more than 45%, preferably less than 30%, in particular less than 20%, the viscosity index being defined as follows: The viscosity index in the context of the present invention denotes the percentage decrease in the viscosity of the compounds of the formula I. at 50 ° C compared to the viscosity at 30 ° C. The viscosity here is the dynamic viscosity (Brookfield, spindle V-73) determined according to DIN EN 12092. The carrier liquids according to the invention may contain not only a compound of the formula I but also mixtures of compounds of the formula I.

The preparation of compounds of formula I per se is known, see, for. Nonionic Surfactants, edited by Martin J. Schick, Volume 2, Chapter 4 (Marcel Dekker, Inc., New York 1967). The preparation of the novel compounds of formula II can be carried out in an analogous manner.

In a preferred embodiment, the carrier liquids for abrasives, in particular cutting fluids, consist of the compound of the formula I. The molecular weight of the compound of the formula I is preferably from 200 to 1200 g / mol. In a further preferred embodiment, in addition to the compounds of the formula I, alkylene alcohols based on ethylene oxides, propylene oxides or copolymers of ethylene and propylene oxides are present, preferably having a molecular weight of from 200 to 800 g / mol. In addition to the compound according to formula I, the cutting fluid in use for sawing contains abrasives, in particular cutting grains.

In a further preferred embodiment, the carrier liquids for abrasives, in particular cutting fluids, are combined with at least one further additive, in particular with at least one

Mono-, oligo- or polyalkylene glycol

 Wetting agents,

Thickeners,

 dispersants,

 Corrosion inhibitor,

 Complexing agent and / or

other additives such as scaling inhibitors

to form a carrier fluid (carrier fluid).

Preferably, at least one of the following additives is added to the following parts by weight per 100 parts by weight of the compound I: alkylene glycols: 10 to 90, in particular 20 to 60 parts by weight

Wetting agent: 1 to 100, especially 10 to 40 parts by weight

Thickener: 0.5 to 20, in particular 1 to 10 parts by weight

Dispersant: 0.1 to 20, especially 0.5 to 10 parts by weight

Corrosion inhibitor: 0.1 to 10, in particular 0.1 to 3 parts by weight

Complexing agent: 0.1 to 10, in particular 1 to 5 parts by weight Other additives: 0.05 to 10, in particular 0.1 to 5 parts by weight

The water content of the composition according to the invention is, based on the total composition, not more than 10, preferably not more than 5, in particular less than 1 wt .-%.

Particularly preferred additives are given below:

wetting agent

In addition to the compounds of the formula I to be used according to the invention, further wetting agents can be used, in particular

(1) poly (oxyalkylene) derivatives of

a) sorbitan esters, e.g. Poly (oxyethylene) sorbitan monolaurate, poly (oxyethylene) sorbitan monooleate, (poly (oxyethylene) sorbitan trioleate)

b) fatty amines, e.g. Tallow aminooxyethylates, soya aminooxyethylates,

c) castor oil, e.g. Rizinusöloxyethylate,

d) alkanolamides, e.g. Coconut oil alkanolamidooxyethylates

e) fatty acids, e.g. For example, oleic acid oxyethylates, lauric acid oxyethylates, oxyethylated oxyethylates

f) fatty alcohols

g) linear alcoholoxyethylates, nonylphenoloxyethylates, octylphenoloxyethylates (2) hydrophilic polydimethylsiloxanes

a) poly (dimethyl) siloxane, poly (dimethylsiloxane) copolymers substituted with at least one carbonyl end group

c) poly (dimethylsiloxane) -b-poly (propylene oxide) -b-poly (ethylene oxide) copolymers d) polyquaternary (dimethylsiloxane) copolymers

(3) fatty imidazolines

(4) fatty acid esters of

a) phosphates

b) sorbitans

c) glycerol compounds, e.g. B.

 Glyceryl monooleate, glyceryl dioleate, glyceryl trioleate, dilaurate

e) Sulphosuccinic acid (5) Quaternary compounds, e.g. B. quaternary ammonium ethosulfate.

Other suitable nonionic, cationic, anionic or amphoteric wetting agents are in particular alkoxylated C ₄ - to C ₂ 2 alcohols such as fatty alcohol alkoxylates or oxoalcohol alkoxylates. These may be alkoxylated with ethylene oxide, propylene oxide and / or butylene oxide. Suitable wetting agents here are all alkoxylated alcohols which contain at least two molecules of one of the abovementioned alkylene oxides added. Here are block polymers of ethylene oxide,

Propylene oxide and / or butylene oxide into consideration or addition products which contain said alkylene oxides in random or blockwise distribution. The nonionic wetting agents generally contain from 2 to 50, preferably from 3 to 20, moles of at least one alkylene oxide per mole of alcohol. The alcohols preferably have 10 to 18 carbon atoms. Depending on the nature of the alkoxylation catalyst used in the preparation, the preparation process and the work-up, the alkoxylates have a broad or narrow alkylene oxide homolog distribution;

Alkylphenolalkoxylate such as Alkylphenolethoxylate with C ₆ - to C ₄ alkyl chains and 5 to 30 alkylene oxide units;

 Alkylpolyglucosides having 8 to 22, preferably 10 to 18 carbon atoms in the alkyl chain and generally 1 to 20, preferably 1, 1 to 5, glucoside units Sorbitanalkanoate, also alkoxylated;

 N-alkylglucamides, fatty acid alkoxylates, Fettsäureaminalkoxylate, Fettsäureamidalkoxylate, Fettsäurealkanolamidalkoxylate, alkoxylated, block copolymers of ethylene oxide, propylene oxide and / or butylene oxide, polyisobutene ethoxylates, polyisobutene-maleic anhydride derivatives, optionally alkoxylated monoglycerides, glycerol monostearates, sorbitan esters and bisglycerides.

Particularly suitable nonionic wetting agents are alkyl alkoxylates or mixtures of alkyl alkoxylates, as described, for example, in DE-A 102 43 363, DE-A 102 43 361, DE-A 102 43 360, DE-A 102 43 365, DE-A 102 43 366, DE-A 102 43 362 or in DE-A 43 25 237 are described. These are alkoxylation products obtained by reacting alkanols with alkylene oxides in the presence of alkoxylation catalysts or mixtures of alkoxylation products. Particularly suitable starter alcohols are the so-called Guerbet alcohols, in particular ethylhexanol, propylheptanol and butyloctanol. Particularly preferred is propylheptanol. Preferred alkylene oxides are propylene oxide and ethylene oxide, with alkyl alkoxylates with direct attachment of a preferably short Poylypropylenoxidblocks to the starter alcohol, as described for example in DE-A 102 43 365, are particularly preferred because of their low residual alcohol content and their good biodegradability. A preferred class of suitable nonionic wetting agents are the alcohol alkoxylates of the general formula (Nl)

R ¹ -O- (CH ₂ -CHR ⁵ -O-) _r (CH ₂ -CH ₂ -O-) n (CH ₂ -CHR ⁶ -O-) s (CH ₂ -CHR ² -O-) _m H (Nl) meaning

R at least single branched C ₄ . ₂₂ -alkyl or -alkylphenol,

R ² C ₃ . _4- alkyl

R ^{5 is} C 1-4 -alkyl

R ^{6 is} methyl or ethyl

n mean value from 1 to 50

m mean value from 0 to 20, preferably 0.5 to 20

r mean value from 0 to 50

s mean value from 0 to 50,

where m is at least 0.5 when R ^{5 is} methyl or ethyl or r is 0.

It may also be a mixture of 20 to 95 wt .-%, preferably 30 to 95 wt .-% of at least one above alcohol alkoxylate and 5 to 80 wt .-%, preferably 5 to 70 wt .-%, of a corresponding alcohol alkoxylate, in which R ^1, however, is an unbranched alkyl radical having the same carbon number act.

It may also be alcohol alkoxylates of the general formula (NN)

R ³ -O- (CH ₂ -CH ₂ -O) _p (CH ₂ -CHR ⁴ -O-) _q H (NN) meaning

R ³ branched or unbranched C ₄ . ₂₂ -alkyl or -alkylphenol,

R ⁴ C ₃ . _4- alkyl

p average value of 1 to 50, preferably 4 to 15

q average value of 0.5 to 20, preferably 0.5 to 4, more preferably 0.5 to 2 act. Further, it may be a mixture of 5 to 95 wt .-% of at least one branched alcohol alkoxylate (NN), as described immediately above, and 5 to 95 wt .-% of a corresponding alcohol alkoxylate, in which instead of a branched alkyl but a unbranched alkyl is present.

In the alcohol alkoxylates of the general formula (NI) R ^{2 is} preferably propyl, in particular n-propyl.

Preferably, in the alcohol alkoxylates of the general formula (NN) n has an average value of 4 to 15, particularly preferably 6 to 12, in particular 7 to 10.

Preferably, m has an average value of 0.5 to 4, particularly preferably 0.5 to 2, in particular 1 to 2. The radical R ¹ is preferably C ₈ -15, particularly preferably C ₈ -13, in particular C ₈ .i ₂ -alkyl radical which is branched at least once. There may also be multiple branches.

R ⁵ is preferably methyl or ethyl, especially methyl.

R ⁶ is preferably ethyl.

In the mixtures there are compounds with unbranched and branched alcohol radicals R ¹ . This is the case, for example, with oxo alcohols which have a proportion of linear and a proportion of branched alcohol chains. For example, a Ci _{3 /} i ₅ -Oxoalkohol often about 60 wt .-% of completely linear alcohol chains, but also about 40 wt .-% α-methyl branched and C> ₂ -branched alcohol chains.

In the alcohol alkoxylates of the general formula (NN), ^R3 is preferably a branched or unbranched C ₈ -15 alkyl group, more preferably a branched or unbranched C ₈ .i ₃ alkyl radical and especially a branched or unbranched C. _{8 12-} alkyl radical. R ⁴ is preferably propyl, especially n-propyl. p preferably has an average value of 4 to 15, particularly preferably an average value of 6 to 12 and in particular a mean value of 7 to 10. q preferably has an average value of 0.5 to 4, particularly preferably 0.5 to 2, in particular 1 to 2.

According to the alcohol alkoxylates of the general formula (Nl), the alcohol alkoxylates of the general formula (NN) may also be present as mixtures with unbranched and branched alcohol radicals. Alcohol components on which the alcohol alkoxylates are based are not only pure alkanols, but also homologous mixtures having a range of carbon atoms. Examples are C ₈ / i o-alkanols, Ci o / 12-alkanols, Ci ₃ / i ₅ alkanols, Ci 2 / i 5-alkanols. It is also possible to mix several alkanols.

The above alkanol alkoxylates or mixtures according to the invention are preferably prepared by reacting alcohols of the general formula R ¹ -OH or R ³ -OH or mixtures of corresponding branched and unbranched alcohols, optionally first with C ₃ . ₆ -alkylene oxide, then with ethylene oxide and subsequently optionally with C ₃ . ₄ -alkylene oxide and then with a corresponding C ₅ . ₆ - Alkylene oxide. The alkoxylations are preferably carried out in the presence of alkoxylation catalysts. In particular, basic catalysts such as potassium hydroxide are used. By special alkoxylation catalysts such as modified bentonites or hydrotalcites, as described, for example, in WO 95/04024, the statistical distribution of the amounts of the incorporated alkylene oxides can be greatly reduced, so that one obtains "narrow-range" alkoxylates.

In a particular embodiment of the present invention, alkoxylate mixtures containing alkoxylates of the general formula (NIM)

C ₅ H ₁₁ CH (C ₃ H ₇ ) CH ₂ O (B) _p (A) _n (B) _m (A) _q H (NIM) meaning A ethyleneoxy

Each independently C ₃ _i ₀ alkyleneoxy, preferably propyleneoxy, butyleneoxy, pentyleneoxy or mixtures thereof, wherein groups A and B are in the form of blocks in the order given, p number from 0 to 10 n number greater than 0 to 20, m number greater than 0 to 20 q number greater than 0 to 10 p + n + m + q at least 1 wherein 70 to 99 wt .-% alkoxylates A1, in which C ₅ Hn has the meaning nC ₅ Hn, and

1 to 30 wt .-% alkoxylates A2, in which C ₅ Hn has the meaning CaHsCl-KCl-yCHz and / or CH ₃ CH (CH ₃ ) CH ₂ CH ₂ , present in a mixture.

In the general formula (NIM), p is a number from 0 to 10, preferably 0 to 5, in particular 0 to 3. If blocks (B) _p are present, p is preferably a number from 0.1 to 10, particularly preferably 0, 5 to 5, in particular 1 to 3.

In the general formula (NIM), n is preferably a number in the range of 0.25 to 10, especially 0.5 to 7, m is preferably a number in the range of 2 to 10, especially 3 to 6. B is preferably propyleneoxy and / or butyleneoxy, especially propyleneoxy at both positions. q is preferably a number in the range of 1 to 5, more preferably in the range of 2 to 3.

The sum p + n + m + q is at least 1, preferably 3 to 25, more preferably 5 to 15, in particular 7 to 13.

The alkoxylates preferably contain 3 or 4 alkylene oxide blocks. According to one embodiment, the alcohol residue is then initially followed by ethyleneoxy units, followed by propylene oxide units and subsequently ethyleneoxy units. According to a further embodiment, the alcohol radical is then initially followed by propyleneoxy units, then ethyleneoxy units, then propyleneoxy units and finally ethyleneoxy units. Instead of the propyleneoxy units, the other indicated alkyleneoxy units may also be present. p, n, m and q denote an average value, which results as an average for the alkoxylates. Therefore, p, n, m, q can also differ from integer values. In the alkoxylation of alkanols, a distribution of the degree of alkoxylation is generally obtained, which can be adjusted to some extent by using different alkoxylation catalysts. By selecting suitable ter amounts of groups A and B, the property spectrum of the alkoxylate mixtures according to the invention can be adjusted depending on the practical requirements.

The alkoxylate mixtures are obtained by alkoxylation of the parent alcohols C5H ₁₁ CH (C ₃ H7) CH ₂ OH. The starting alcohols can be mixed from the individual components, resulting in the ratio according to the invention. They can be prepared by aldol condensation of valeraldehyde and subsequent hydrogenation. The preparation of valeraldehyde and the corresponding isomers is carried out by hydroformylation of butene, as described for example in US 4,287,370; Beilstein E IV 1, 32 68, Ullmann's Encyclopedia of Industrial Chemistry, 5th Edition, Volume A1, pages 323 and 328 f. The subsequent aldol condensation is described, for example, in US Pat. No. 5,434,313 and Römpp, Chemie Lexikon, 9th edition, keyword "Aldol addition" on page 91. The hydrogenation of the aldol condensation product follows general hydrogenation conditions.

Further, 2-propylheptanol can be prepared by condensation of 1-pentanol (as a mixture of the corresponding methylbutanols-1) in the presence of KOH at elevated temperatures, see e.g. Marcel Guerbet, CR. Acad Be Paris 128, 511, 1002 (1899). Furthermore, Römpp, Chemie Lexikon, 9th edition, Georg Thieme Verlag Stuttgart, and the quotations mentioned therein and Tetrahedron, Vol. 23, pages 1723-1733, should be noted.

In the general formula (NIM), the radical C, the meaning nC ₅ H n, C ₂ H ₅ CH (CH ₃₎ CH 2 or CH ₃ CH ₅ Hn (CH ₃₎ CH ₂ CH 2 have. The alkoxylates are mixtures in which

70 to 99 wt .-%, preferably 85 to 96 wt .-% alkoxylates A1 are present, in which C ₅ Hn has the meaning nC ₅ Hn, and - 1 to 30 wt .-%, preferably 4 to 15 wt .-% Alkoxylates A2 in which C ₅ Hn has the meaning C ₂ H ₅ CH (CH ₃ ) CH ₂ and / or CH ₃ CH (CH ₃ ) CH ₂ CH ₂ .

The radical C ₃ H ₇ preferably has the meaning nC ₃ H ₇ . It may also be block-shaped iso Tridecanolalkoxylate the general formula (NV)

R-O- (C _m H _2m O) _x - (C _n H _2n O) _y H (NV)

in the

R denotes an iso-tridecyl radical, m is the number 2 and at the same time n is the number 3 or 4 or m is the number 3 or 4 and at the same time n is the number 2 and

x and y independently of one another represent numbers from 1 to 20,

where, in the case m = 2 / n = 3 or 4, the variable x is greater than or equal to y.

These block-shaped iso-Tridecanolalkoxylate are described for example in DE 196 21 843 A1.

Another suitable nonionic surfactant class is end-capped alcohol alkoxylates, especially of the aforementioned alcohol alkoxylates. In a particular embodiment, these are the corresponding end-capped alcohol alkoxylates of the alcohol alkoxylates of the general formulas (III), (NN), (NIM) and (NV). The end group closure can be carried out, for example, using dialkyl sulfate, C 1-10 -alkyl halides, C 1-10 -halohalides, preferably -chlorides, -bromides, particularly preferably cyclohexyl chloride, cyclohexyl bromide, phenyl chloride or phenyl bromide.

Examples of end-capped alkoxylates are also described in DE-OS 37 26 121, the entire disclosure of which is included in the present invention by reference. In a preferred embodiment, these alcohol alkoxylates have the general structure (NVI),

R ^l -0- (CH2-CHR ^ll -0) _m. (CH ₂ -CHR ^III O) nR ^lv (NVI), in the

R 'is hydrogen or CC ₂ o-alkyl,

R "and R ^{m are the} same or different and are each independently of one another hydrogen, methyl or ethyl,

R ^{IV is} C 1 -C ₄ -alkyl, preferably C ₄ -alkyl, or cyclohexyl or phenyl, m 'and n' are the same or different and are greater than or equal to 0,

with the proviso that the sum of m 'and n' is 3 to 300.

Another class of nonionic surfactants are alkyl polyglucosides having preferably 6 to 22, more preferably 10 to 18, carbon atoms in the alkyl chain. These compounds generally contain 1 to 20, preferably 1, 1 to 5 glucoside units.

Further suitable nonionic wetting agents are the end-capped fatty acid amide alkoxides of the general formula ## STR4 ## known from WO-A 95/1 1225 R'-CO-NH- (CH ₂ ) _y -O- (A ¹ O) _x -R ² in the

R ¹ denotes a C ₅ - to C ₂ -alkyl or alkenyl radical,

R ^{2 is} a C 1 to C ₄ alkyl group,

A 'is C ₂ - to C ₄ -alkylene,

y denotes the number 2 or 3 and

x has a value of 1 to 6.

Examples of such compounds are the reaction products of n-butyltriglycolamine of the formula H ₂ N- (CH ₂ -CH ₂ -O) 3-C ₄ H ₉ with dodecanoic acid methyl ester or the reaction products of ethyltetraglycolamine of the formula H ₂ N- (CH ₂ -CH ₂ -O) ₄ - C ₂ H ₅ with a commercially available mixture of saturated C ₈ - to C ₈ fatty acid methyl esters.

Also suitable as nonionic wetting agents are polyhydroxy or polyalkoxy fatty acid derivatives such as polyhydroxy fatty acid amides, N-alkoxy or N-aryloxy polyhydroxy fatty acid amides, fatty acid amide ethoxylates, in particular end-capped, and fatty acid alkanolamide alkoxylates.

Still further, the block copolymers suitable for use as nonionic surfactants of ethylene oxide, propylene oxide and / or butylene oxide (Pluronic ^® - and Tetronic ^® BASF SE BASF Corp. or grades). In a preferred embodiment, triblock copolymers having polyethylene / polypropylene / polyethylene blocks and a molecular weight of 4,000 to 16,000, wherein the weight fraction of the polyethylene blocks is 55 to 90%, based on the triblock copolymer. Particular preference is given to triblock copolymers having a molecular weight of more than 8,000 and a polyethylene content of from 60 to 85% by weight, based on the triblock copolymer. These preferred triblock copolymers are particularly commercially available under the names Pluronic F127, Pluronic F108 and Pluronic F98, each from BASF Corp., and described in WO 01/47472 A2, the entire disclosure of which is incorporated by reference into the present invention.

In addition, block copolymers of ethylene oxide, propylene oxide and / or butylene oxide, which are closed on one or two sides, can preferably also be used. A one-sided closure can be achieved, for example, by using as starting compound for the reaction with an alkylene oxide an alcohol, in particular a Ci- ₂₂ alkyl alcohol, for example methanol used. In addition, one can-for example, the two-sided Endgruppenverschluss - by reaction of the free block copolymer with dialkyl sulfate, Ci_io-alkyl halides, Ci_io-phenyl halides, preferably chlorides, bromides, particularly preferably cyclohexyl chloride, cyclohexyl bromide, phenyl chloride or phenyl bromide effect.

It is additionally possible to use individual nonionic wetting agents or a combination of different nonionic surfactants. It is possible to use nonionic wetting agents of only one class, in particular only alkoxylated C ₄ - to C ₂₂ -alcohols. Alternatively, one can also use wetting agent mixtures from different classes.

The concentration of nonionic wetting agent in the composition of the invention may vary depending on the conditions of leaching, in particular depending on the material to be leached.

Suitable anionic wetting agents are alkanesulfonates such as C ₈ to C ₂₄ , preferably cio to cis alkanesulfonates and soaps such as the Na and K salts of saturated and / or unsaturated C ₈ . to C ₂₄ carboxylic acids.

Further suitable anionic wetting agents are linear C ₈ - to C ₂ o-alkylbenzenesulfonates ("LAS"), preferably linear C ₉ - to C -alkylbenzenesulfonates and -alkyltoluenesulfonates

Thickeners are compounds that increase the viscosity of the chemical composition. Non-limiting examples are for. As specified in WO 2009/090169 A1: polyacrylates and hydrophobically modified polyacrylates. The advantage of using thickeners is that higher viscosity fluids on inclined or vertical surfaces have a longer residence time than lower viscosity fluids. This increases the interaction time between composition and surface. Further particularly suitable thickeners are, for example, bentonite, xanthan and cellulose and also cellulose derivatives, in particular cellulose ethers and cellulose esters, in particular methylcellulose, hydroxyethylcellulose and carboxymethylcellulose. Further examples of thickeners are polyacrylamides, polyethers or associative polyurethane thickeners, polyvinyl alcohols and polyvinylpyrrolidones. Dispersants / scale inhibitors

In addition, according to the invention, at least one dispersing agent, for example selected from the group consisting of salts of naphthalenesulfonic acids, condensation products of naphthalenesulfonic acids and formaldehyde and also polycarboxylates, can additionally be used. Appropriate dispersing agents are commercially available for example under the trade name Tamol ^®, Sokalan ^® and Nekal ^® from BASF SE as well as under the trade name Solsperse ^® from Lubrizol. If appropriate, these dispersants can also act as scale inhibitors (coating inhibitors), since they disperse the calcium carbonate CaCO ₃ forming in the alkaline medium and thus prevent, for example, clogging of nozzles or deposit formation in pipelines. Independently of this, the composition according to the invention may additionally contain at least one further scaling inhibitor. Suitable scale inhibitors are described, for example, in WO 04/099092 which describes (meth) acrylic acid copolymers which

(a) from 50 to 80% by weight, preferably from 50 to 75% by weight, particularly preferably from 55 to 70% by weight, of a poly (meth) acrylic acid skeleton,

 (b) from 1 to 40% by weight, preferably from 5 to 20% by weight, more preferably from 7 to 15% by weight, of at least one unit bonded to the backbone and / or incorporated into the backbone from the

Group consisting of isobutene units, terelactone units and isopropanol units and

 (c) 5 to 50% by weight, preferably 5 to 40% by weight, particularly preferably 10 to 30% by weight, of amide units based on aminoalkylsulfonic acids, the total weight of the units in the (meth) acrylic acid copolymer being 100% by weight .-% and all weights are based on the (meth) acrylic acid copolymer. The (meth) acrylic acid copolymers provided according to WO 04/099092 preferably have a weight-average molecular weight of the sulfone-containing polymer of from 1,000 to 20,000 g / mol and can preferably be prepared by the following process steps:

 (1) radical polymerization of (meth) acrylic acid in the presence of

Isopropanol and optionally water, resulting in a polymer I, and (2) amidation of the polymer I from process step (1) by reaction with at least one aminoalkanesulfonic acid.

Further suitable scaling inhibitors are, for example:

 Polycarbonsäurehalbamide, which are obtainable by reaction of anhydride-containing polymers and amino-containing compounds (according to DE 195 48 318),

 Vinyl lactic acid and / or isopropenyl lactic acid (according to DE 197 195 16), homopolymers of acrylic acid (according to US Pat. No. 3,756,257),

 Copolymers of acrylic acid and / or (meth) acrylic acid and vinyl lactic acid and / or isopropenyl lactic acid,

 Copolymers of styrene and vinyl lactic acid,

 Copolymers of maleic acid and acrylic acid,

 Water-soluble or water-dispersible graft polymers obtainable by free-radically initiated graft polymerization of

 (I) at least one monoethylenically unsaturated monomer

 (II) polymers having a molecular weight of from 200 to 5000 g / mol of monoethylenically unsaturated dicarboxylic acids or their anhydrides,

(III) using from 5 to 2000 parts by weight (I) per 100 parts by weight of the graft base (II) (DE 195 03 546),

 optionally hydrolyzed polymaleic anhydrides and their salts (according to US-A-3 810 834, GB-A-1 454 657 and EP-A-0 261 589),

 Iminodisuccinate (according to DE 101 02 209),

 Formulations containing complexing agents such as ethylenediaminetetraacetic acid (EDTA) and / or diethylenetriaminepentaacetic acid (DTPA) (according to US Pat

5,366,016)

 phosphonates,

 polyacrylates,

 Polyaspartic acids or according to DE-A-44 34 463 modified polyaspartic acids,

 polyaspartimides,

 Hydroxamic acid, hydroxamic acid and / or hydrazide group-containing polymers (according to DE 44 27 630),

 optionally hydrolyzed polymers of maleimide (according to DE 43 42 930),

 Naphthylamine polycarboxylates (according to EP 0 538 969),

 Oxaalkane polyphosphonic acids (according to EP 330 075),

 Polyhydroxyalkane-amino-bis-methylenephosphonic (according to DE 40 16 753) and

- Oxidized polyglucosans (according to DE 43 30 339). Particularly preferred dispersants are polyacrylic acid, such as Sokalan from BASF SE ^® types and polyaspartic acids, in particular .beta.-polyaspartic acids with a molecular weight of 2,000 to 10,000 g / mol. Preferred as polymeric compounds containing carboxylic acid groups are the acrylic acid homopolymers specified in EP 2 083 067 A1. These preferably have a number-average molecular weight in the range from 1000 to 50,000, more preferably from 1,500 to 20,000. Homopolymers of acrylic acid which are particularly suitable as polymeric compounds containing carboxylic acid groups are the Sokalan® PA grades from BASF SE.

Suitable polymeric compounds containing carboxylic acid groups are also oligomaleic acids, as described, for example, in EP-A 451 508 and EP-A 396 303.

Further preferred as polymeric compounds containing carboxylic acid groups are copolymers which comprise in copolymerized form as monomer A) at least one unsaturated mono- or dicarboxylic acid or a dicarboxylic acid anhydride or a salt thereof and at least one comonomer B). Preferably, the monomer A) is chosen from C ₃ -C ₀ monocarboxylic acids, salts of C ₃ -C ₀ monocarboxylic acids, C ₄ -C ₈ - dicarboxylic acids, anhydrides of C ₄ -C ₈ dicarboxylic acids, salts of C ₄ -C ₈ - dicarboxylic acids and mixtures thereof. Monomers A) in salt form are preferably used in the form of their water-soluble salts, in particular the alkali metal salts, such as potassium and especially sodium salts or ammonium salts. The monomers A) can each be completely or partially in anhydride form. Of course, it is also possible to use mixtures of the monomers A).

The monomers (A) are preferably selected from acrylic, methacrylic, crotonic, vinylacetic, maleic, maleic, fumaric, citraconic, citraconic, itaconic and mixtures thereof. Particularly preferred monomers (A) are acrylic acid, methacrylic acid, maleic acid, maleic anhydride and mixtures thereof. These copolymers preferably comprise at least one monomer A) in an amount of from 5 to 95% by weight, particularly preferably from 20 to 80% by weight, in particular from 30 to 70% by weight, based on the total weight of the monomers used for the polymerization, in copolymerized form.

corrosion inhibitors

As corrosion inhibitors z. B. in WO 2008/071582 A1 specified means, for. B. carboxylic acids. These can be straight-chain or branched. mixtures various carboxylic acids may be particularly preferred. Caprylic acid, ethylhexanoic acid, isononanoic acid and isodecanoic acid are particularly preferred carboxylic acids. Since anticorrosive emulsions are often neutral to slightly alkaline, it may be advantageous to use the carboxylic acids at least partially in neutralized form, ie as a salt. Particularly suitable for neutralization are sodium and / or potassium hydroxide, as well as alkanolamines. Particularly preferred is the use of mono- and / or trialkanolamines. The use of dialkanolamines is less preferred because of the danger of formation of nitrosamines. However, dialkanolamines can also be used alone or together with mono- and / or trialkanolamines for neutralization.

Suitable corrosion inhibitors are in particular: aliphatic carboxylic acid amides having 14 to 36 carbon atoms, for example myristic acid amide, palmitic acid amide and oleic acid amide; Alkenylsuccinamides having 6 to 36 carbon atoms, for example octenylsuccinamide, dodecenylsuccinamide; Mercatobenzothiazole. Particularly preferred corrosion inhibitors are alkylene oxide adducts with aliphatic amines, particularly triethanolamine and ethylenediamine adducts with 2 to 8 mol% of propylene oxide.

complexing

Complexing agents are compounds that bind cations. Typical examples are: EDTA (Ν, Ν, Ν ', Ν'-ethylenediaminetetraacetic acid), NTA (Ν, Ν, Ν-nitrilotriacetic acid), MGDA (2-methyl-glycine-N, N-diacetic acid), GLDA (glutamic acid diacetate), AS DA (aspartic acid diacetate), IDS (iminodisuccinate), HEIDA (hydroxyethylimine diacetate), EDDS (ethylenediamine disuccinate), citric acid, oxodisuccinic acid and butanetetracarboxylic acid or their fully or partially neutralized alkali metal or ammonium salts.

Other additives

Further suitable additives are, for example, adhesion promoters. Suitable adhesion promoters are, for example, the amphiphilic water-soluble alkoxylated polyalkyleneimines of the general formula AI given in WO 2006/108856 A2 B

E ₂ N - R - N - R - N - R - z NE,

 J y AI in which the variables have the following meaning:

R is the same or different, linear or branched C 2 -C 6 -alkylene radicals;

 B a branch;

E is an alkyleneoxy unit of the formula

R1 is 1, 2-propylene, 1, 2-butylene and / or 1, 2-isobutylene;

 R2 ethylene;

 R3 1, 2-propylene;

R4 is the same or different radicals: hydrogen; C1-C4 alkyl;

x, y, z are each a number from 2 to 150, where the sum x + y + z is a number from

Alkylenimineinheiten means the average molecular weight Mw of

Polyalkylenimins before the alkoxylation of 300 to 10,000 corresponds;

m is a rational number from 0 to 2;

n is a rational number from 6 to 18;

p is a rational number from 3 to 12, where 0.8 <n / p <1, 0 (x + y + z) is 1/2.

The invention further relates to a slurry of the carrier liquid, in particular cutting fluid, abrasives, in particular grinding and / or cutting grains, and optionally additives.

The usual abrasives, in particular grinding and / or cutting grains, can be used, for example metal, metal or semimetal, carbide, nitride, oxide, boride or diamond grains. Particularly preferred cutting grains are carbide and boride, in particular silicon carbide (SiC) grains. The cutting grains preferably have an adapted geometry depending on the materials and the wafers to be cut; a preferred particle size is between 0.5 and 50 μm. The cutting grains may be in heterodisperse or homodisperse form. The cutting grains are preferably contained in the cutting fluid composition in a concentration of 25 to 60% by weight, especially 40 to 50% by weight. In a particularly preferred embodiment, the carrier liquid, in particular cutting fluid, a contact angle against V2A steel from 5 to 40 °, in particular from 10 to 30 °. The contact angle is determined here at 25 ° C on a steel plate made of V2A steel, the surface was rinsed with water and acetone.

In a further preferred embodiment, the carrier fluids according to the invention, in particular cutting fluids, lead on average to a balance of the designation MDD2, Hermann Reichert Maschinenbau, Heidenhof Backnang, at a loading of 300 N and a running distance of 110 m and two repeated tests Weight loss of a maximum of 20 to 60 mg in one minute on a stainless steel cylinder of the designation M1 M6 / 05R, Torrington with a diameter of 12 mm. In a further preferred embodiment, the carrier liquids according to the invention, in particular cutting fluids, after storage in a Heraeus BBD 6220 CO 2 incubator at 38 ° C. and 78% relative humidity take a maximum of 30, preferably a maximum of 15% water after a time of 10 hours on. For storage, in each case 1 g of carrier liquid, in particular cutting fluid, are used in petri dishes of an inner diameter of 60 mm. In each case, the mean value of a double determination is determined. In a very particularly preferred embodiment, this water absorption no longer increases even with further exposure. A slurry of a carrier liquid according to the invention, in particular cutting fluid, and of 40 wt .-% of Abrasiva specified below, in particular grinding and / or cutting grains, preferably has a viscosity, measured at 30 ° C with a Brookfield LVDV-III Ultravorrichtung (Spindle V-73), from 140 to 200 mPas, in particular from 150 to 190 mPas, being used as Carborex BWF 800 PV silicon carbide grains from Washington Mills.

The invention further relates to a method for cutting wafers from in particular inorganic semiconductors, such as silicon ingots or silicon ingots, with a wire saw using a slurry based on the cutting fluid according to the invention and of cutting grains.

The invention further relates to a method for grinding or polishing materials from, for example, silicon ingots or ingots by, for example, chemical mechanical polishing (CMP) or for grinding plastics, in particular for lenses, using abrasives which are dispersed in a carrier liquid to be used according to the invention.

advantages

The carrier liquid according to the invention, in particular cutting fluid and the method according to the invention for cutting is particularly suitable for sawing ingots, ingots or cylinders (ingots) of monocrystalline or polycrystalline silicon single crystals or polycrystals, GaAs, CdTe and other semiconductors and ceramics.

The carrier liquid according to the invention, in particular cutting fluid, is characterized in that it has little or no foaming, requires no additives, is pH-neutral and is not toxic. In addition, it contains no volatile organic components. Furthermore, the carrier liquid according to the invention, in particular cutting fluid, is outstandingly suitable for reprocessing by chemical-technical wet processing, for example in accordance with WO 02/40407 A1 and EP 1 390 184 A1.

Examples:

General preparation for polyethers

In an anhydrous, dry 11 pressure reactor each 1-2 mol of the starter alcohol were initially charged and mixed with 0.2Gew% (based on the final product) of KOH and purged with nitrogen. The closed reactor was then heated to 130 ° C. for 30 minutes and an excess pressure of 1 bar was set with nitrogen. Subsequently, the molar amounts of propylene oxide (hereinafter PO) and ethylene oxide (hereinafter EO) indicated in Table 1 were added in parallel (random mode) or in succession (block mode) with stirring. In the block mode, after PO addition and reaching the constant pressure before the EO addition, at least Vz hour was stirred at 130 ° C. and the pressure was adjusted to 1 bar. During the reaction, the container was thermostated at 130 ° C. After reaching the constant pressure was stirred for about ¹ / hour. After the reaction had ended, the mixture was cooled to 80 ° C., the reactor was decompressed and flushed with nitrogen, and the amount of glacial acetic acid calculated to neutralize the KOH was added and stirring was continued for 1 hour.

The OH number was determined according to DIN 51562, the residual alcohol by gas chromatography and the color number APHA according to EN 1557 (at 23 ° C.). Table 1: Examples and analytical characterization

Bei den in den Beispielen C6 und C7 zugesetzten Netzmitteln bzw. Alkylenglykolen Pluronic® PE 6200 bzw. Plurafac® LF 401 handelt es sich um Handelsprodukte der BASF SE, Ludwigshafen. Die angegebenen analytischen Daten beziehen sich auf die erfindungsgemäße Komponente Pentanol+1 ,5 PO + 6EO, Block Fahrweise. Eigenschaften/ Bestimmung der kennzeichnenden Werte

The wetting agents or alkylene glycols Pluronic® PE 6200 or Plurafac® LF 401 added in Examples C6 and C7 are commercial products of BASF SE, Ludwigshafen. The indicated analytical data refer to the component of the invention pentanol + 1, 5 PO + 6EO, block mode. Properties / Determination of the characteristic values

The properties of the cutting fluids according to the invention are summarized in Table 2. The following properties were determined:

• Water absorption

 The water uptake of the cutting fluids was determined after storage in a Heraeus BBD 6220 C02 incubator at 38 ° C. and 78% relative humidity after 10 hours and 24 hours, respectively. For storage, 1 g of cutting fluid was used in Petri dishes of an inner diameter of 60 mm. In each case, the mean value of a duplicate determination was determined. The water absorption is given in percent by weight increase based on weight.

· Slurry viscosity

 To determine the slurry viscosity, a mixture of 60% by weight of the sawing liquid and 40% by weight of Carborex BW F 800 PV SiC manufactured by Washington Mills and the viscosity at 30 ° C and optionally 50 ° C with a viscometer from Brookfield, Model LVDV-III Ultra (Spindle V-73). The slurry viscosity is given in mPas.

• contact angle

The contact angle of the cutting fluids was determined at 25 ° C. one second after drop application on a steel plate made of V2A steel, the surface of which was rinsed with water and acetone and then dried in air for 1 h. For the determination, a video-assisted high-speed contact angle measuring device from Dataphysics Instruments GmbH, Raiffeisenstrasse 34, Filderstadt was used. The unit of the contact angle is given in °.

• abrasion

The abrasion behavior was on a Rebverschleißwaage the designation MDD2, company Hermann Reichert mechanical engineering, Heidenhof Backnang, at a load of 300 N and a running distance of 100 m in 54.5 seconds on a stainless steel cylinder of the designation M1 M6 / 05R, Torrington with a diameter determined by 12 mm. A double determination was carried out in each case and the mean value of the weight decrease of the cylinder was determined. The weight loss is given in mg. Table 2

Bei Pluriol® E 200 handelt es sich um ein Polyethylenglykol der mittleren Molmasse 200 der Firma BASF SE, Ludwigshafen. Das Beispiel repräsentiert den Stand der Technik und ist nicht erfindungsgemäß. Mit den Verbindungen 11.1 und II.2 wurden vergleichbare Ergebnisse wie bei den Verbindungen C2 und C3 erhalten. Praxisversuch

Pluriol® E 200 is a medium molecular weight polyethylene glycol 200 from BASF SE, Ludwigshafen. The example represents the prior art and is not according to the invention. Compounds 11.1 and II.2 gave comparable results to compounds C2 and C3. field trial

On a wire saw DS 265 from Meyer Burger AG, Allmendstrasse 86, CH 3600 Thun sawing tests were carried out on polycrystalline silicon blocks using the sawing liquids C1 and C3. The experimental conditions were:

Dimensions of the wafers: 5 "x 5", 150 μηι

 SiC quality: F 88, ds50 = 6.5 μηι

 Feed rate: 0.6 mm / s

 Wire speed: 14 m / s

 Wire diameter: 120 μηι

 Wire tension: 20 N

 Slurry temperature: 22 ° C

 Composition of the slurry: 60% by weight of sawing fluid, 40% by weight of SiC

In comparison with the PEG 200 (Pluriol® E 200) commonly used in practice, the following improvements were found for the cutting fluids according to the invention: Pluriol® E 200 C1 C3

 Water absorption, [% by weight] 3 <0.5 <0.5

 Force per wire in feed direction, [N] 0.62 0.57 0.58

 Force per wire in the wire direction, [N] 1, 62 1, 51 1, 55

 Power consumption per wire, [W] 29.5 24.0 26.5

 (without machine part)

 TTV, 5 point edition, [%] 12.5 1 1, 8 10.5

 (total thickness variation of wafers)

 Critical stress at break, [N / mm2] 158 163 178

Similar improvements have also been found using the other products of the invention indicated in Table 1.

Claims

claims Use of compounds of the formula I R [O (EO) _x (AO) _y H] _z in which R is a z-valent alkyl radical having 1 to 20 C atoms  (EO) ethyleneoxy radical  (AO) Alkyleneoxy radical having 3 to 10 C atoms  x is a number from 3 to 12, in particular 5 to 10  y is a number from 0 to 10, in particular 4 to 8  z is a number from 1 to 6, in particular 1 to 3 for the production of carrier liquids for Abrasiva, in particular cutting fluids, with reduced water absorption for removing material, in particular for sawing wafers with a wire saw. Use according to claim 1, characterized in that in the formula I mean R ^{1 is} a z-valent alkyl radical having 5 to 10 C atoms, in particular pentyl. Use according to at least one of the preceding claims, characterized in that the contact angle of the cutting fluid on V2A steel at 25 ° C is 25 to 50 °. Use according to at least one of the preceding claims, characterized in that the wafer is a semiconductor, in particular silicon. Use according to at least one of the preceding claims, characterized in that the carrier liquid, in particular cutting fluid, is used in a slurry together with cutting grains, wherein metal, carbide, nitride, metal oxide, boride or diamond grains are used as cutting grains. 6. Use according to at least one of the preceding claims, characterized in that the carrier liquid, in particular cutting fluid, is worked up during or after removal of the material, in particular after cutting for the separation of the obtained abrasion. 7. Carrier liquid, in particular cutting fluid, containing at least one compound of the formula I. R ¹ [O (EO) _x (AO) _y H] _z in which R is a z-valent alkyl radical having 5 to 10 carbon atoms  (EO) ethyleneoxy radical  (AO) Alkyleneoxy radical having 3 to 10 C atoms  x is a number from 3 to 12, in particular 5 to 10  y is a number from 0.5 to 10, in particular 4 to 8  z is a number from 1 to 6, in particular 1 to 3. 8. carrier liquid, in particular cutting fluid, according to claim 7, characterized in that R ^{1 is} pentyl. 9. carrier liquid, in particular cutting fluid, according to claim 7, characterized in that the contact angle of the carrier liquid, in particular cutting fluid on V2A steel at 25 ° C is 25 to 50 °. 10. Use of a carrier liquid, in particular cutting fluid, according to at least one of the preceding claims for removing material, in particular when sawing wafers from an object to be cut in particular semiconductor, in particular silicon, with a saw using cutting grains, in particular of Siliziumcarbidkörnern. 1 1. Use of a carrier liquid according to at least one of the preceding claims for polishing materials, in particular for polishing wafers of silicon or of materials made of plastics, in particular for lens production. 12. A method for cutting wafers from an object with a saw using a slurries of a cutting fluid and cutting grains, in particular with cutting grains of metal, a carbide, nitride, oxide, boride, corundum or diamond, characterized in that the cutting fluid a cutting fluid according to at least one of the preceding is claims, which is optionally worked up during or after removal of the material, in particular after cutting, for the separation of the obtained abrasion. Method for polishing materials, in particular of silicon or plastics, using a slurry of a carrier liquid and abrasives, characterized in that a carrier liquid according to at least one of the preceding claims is used as the carrier liquid. Wafers, in particular silicon wafers, obtained according to at least one of the preceding claims. Compounds of the formula II R ¹ O (EO) _x (AO) _y H where R ^{1 is} 2-methylbutyl or 3-methylbutyl and wherein  (EO), (AO), x and y have the meaning given in claim 1.