阅读说明：本技术 一种应用于大尺寸硅片研磨的悬浮助剂、其制备方法及用途 (Suspension auxiliary agent applied to large-size silicon wafer grinding, preparation method and application thereof ) 是由 侯军 李传强 于 2021-07-29 设计创作，主要内容包括：本发明提供一种应用于大尺寸硅片研磨的悬浮助剂、其制备方法及用途,所述悬浮助剂包括重量配比如下的各组分：氢键触变剂0.5-5份；悬浮增效剂0.5-5份；电荷中和剂0.1-1份；分散剂0.5-10份；润滑剂10-20份；防锈剂0.1-0.5份；水50-85份。本发明还公开了上述悬浮助剂的制备方法,包括以下步骤：向去离子水中依次加入分散剂、润滑剂、电荷中和剂和防锈剂；加热至40℃后,向溶液中加入氢键触变剂,乳液静置溶胀稳定；向溶液中加入悬浮增效剂,制备得到应用于大尺寸硅片研磨的悬浮助剂。本发明制备的悬浮助剂可以有效增加复合磨料的悬浮性能,同时对不同磨料具有良好的分散性,避免循环研磨中形成磨料团聚和磨料硬沉淀。(The invention provides a suspension auxiliary agent applied to large-size silicon wafer grinding, a preparation method and application thereof, wherein the suspension auxiliary agent comprises the following components in parts by weight: 0.5-5 parts of hydrogen bond thixotropic agent; 0.5-5 parts of suspension synergist; 0.1-1 part of charge neutralizer; 0.5-10 parts of a dispersing agent; 10-20 parts of a lubricant; 0.1-0.5 part of antirust agent; 50-85 parts of water. The invention also discloses a preparation method of the suspension auxiliary agent, which comprises the following steps: sequentially adding a dispersing agent, a lubricating agent, a charge neutralizing agent and an antirust agent into deionized water; after heating to 40 ℃, adding a hydrogen bond thixotropic agent into the solution, and standing the emulsion for stable swelling; and adding a suspension synergist into the solution to prepare the suspension assistant applied to grinding the large-size silicon wafer. The suspension auxiliary agent prepared by the invention can effectively improve the suspension performance of the composite abrasive, has good dispersibility for different abrasives, and avoids abrasive agglomeration and abrasive hard precipitation in circular grinding.)

1. The suspension aid for grinding large-size silicon wafers is characterized by comprising the following components in parts by weight:

2. the suspension aid for grinding large-size silicon wafers as claimed in claim 1, wherein the hydrogen bond thixotropic agent is a thixotropic agent capable of forming a spatial grid structure by hydrogen bond interaction in a short time in an aqueous solution.

3. The suspension aid for grinding large-size silicon wafers according to claim 1 or 2, wherein the hydrogen bond thixotropic agent is one or more of carboxyl modified bentonite, hydroxyl modified bentonite, amino modified hydrotalcite and carboxyl modified hydrotalcite.

4. The suspension aid for grinding large-size silicon wafers according to claim 1, wherein the suspension synergist is one or more of polyether polyol, polymeric polyether, polymeric polyester, polyvinylamine, polypropyleneimine and polyvinyl alcohol.

5. The suspension aid for grinding large-size silicon wafers as set forth in claim 1, wherein the charge neutralizer is a mixture of one or more of cocamidopropyl betaine, cocoyl dimethylamine oxide, tetradecylamine, hexadecylamine, cocoyl fatty amine, and octadecyl dimethyl benzyl ammonium chloride.

6. The suspension aid for grinding large-size silicon wafers according to claim 1, wherein the dispersant is one or more of polyacrylate, polyurethane, alkoxy polymer and polypropylene-polyphosphate block copolymer.

7. The suspension aid for grinding large-size silicon wafers as claimed in claim 1, wherein the lubricant is one or more of ethylene glycol, polyethylene glycol, glycerol, isohexyl glycol and propylene glycol.

8. The suspension aid for grinding large-size silicon wafers as claimed in claim 1, wherein the rust inhibitor is a mixture of one or more of lauric acid, isododecanoic acid, polyaspartic acid, amino acid, sebacic acid, octanoic acid and polycarboxylic acid.

9. A method for preparing the suspension aid for grinding large-size silicon wafers as claimed in any one of claims 1 to 8, comprising the steps of:

sequentially adding a dispersing agent, a lubricating agent, a charge neutralizing agent and an antirust agent into deionized water under the stirring condition, and stirring for 30-60min until the materials are uniformly mixed;

step (2) heating the solution obtained in the step (1) to 40-50 ℃, adding a hydrogen bond thixotropic agent under continuous stirring at 1500-2500rpm, stirring for 10-30min until a uniform emulsion is formed, stopping high-speed stirring, and standing the emulsion for swelling and stabilizing for more than 1 hour;

and (3) under the condition of low-speed stirring at 50-100r/min, adding the suspension synergist into the solution obtained in the step (2) twice, and stirring for 30-60min until the suspension synergist is uniformly mixed to prepare the suspension aid applied to grinding of large-size silicon wafers.

10. Use of the suspension aid according to any one of claims 1 to 8 in the field of grinding liquids for large-size silicon wafer grinding.

Technical Field

The invention relates to a grinding suspension auxiliary agent technology, in particular to a suspension auxiliary agent applied to large-size silicon wafer grinding, a preparation method and application thereof.

Background

With the development of semiconductor material technology, higher requirements are put forward on the specification and quality of silicon wafers, and the demand proportion of large-diameter silicon wafers suitable for micro-machining in the market is increased day by day. In the manufacturing process of large-size monocrystalline silicon wafers for semiconductors, the grinding technical index of the silicon wafers is more rigorous, the silicon wafers need to have lower roughness, smaller thickness difference, lower damage layer depth and the like, the grinding process is a key step for maintaining the quality of the silicon wafers, and a suspension auxiliary agent used in the step is one of core technologies influencing the grinding index, so that new technical challenges are provided for the suspension property, the lubricating property, the dispersion property and the like of grinding liquid.

At present, silicon wafer grinding fluid mainly comprises grinding materials, deionized water and a suspension auxiliary agent, wherein the grinding materials generally comprise alumina, silica, zirconia and other composite grinding materials, and the types, the appearances, the surface charge conditions and the like of different grinding materials have higher requirements on the suspension auxiliary agent. In the grinding process, grinding materials with various shapes and sizes need to be kept to be uniformly suspended in a system and participate in grinding of the silicon wafer together, so that the grinding efficiency and the surface quality of the ground silicon wafer are ensured. At present, in the process of grinding silicon wafers, because different grinding materials have different hardness and broken particles have different sizes, the stress on the surfaces of the silicon wafers is not uniform, the specific surface area of the grinding materials is increased in the grinding process, and the grinding material fine powder is easy to form agglomeration and coagulation in grinding liquid, so that the grinding speed is reduced and the surfaces of the silicon wafers are scratched, and the processing efficiency and the product yield of the silicon wafers are seriously influenced. And in the process of recycling the grinding fluid, the composite abrasive slurry is easy to form hard precipitate in the pipeline to cause blockage of the infusion pipeline, so that the production is influenced.

Therefore, the development of the suspension auxiliary agent applied to the grinding of the large-size silicon wafer is of great significance.

Disclosure of Invention

The invention aims to provide a suspension auxiliary agent applied to large-size silicon wafer grinding, aiming at the problems that the grinding rate of the existing silicon wafer grinding liquid is low and the surface of the silicon wafer grinding liquid is easy to scratch, wherein the suspension auxiliary agent can effectively increase the suspension performance of a composite grinding material, has good dispersibility for different grinding materials, and avoids the formation of grinding material agglomeration and grinding material hard precipitation in circular grinding.

In order to achieve the purpose, the invention adopts the technical scheme that: a suspension aid for grinding large-size silicon wafers comprises the following components in parts by weight:

furthermore, the hydrogen bond thixotropic agent is a thixotropic agent which can form a space grid structure through hydrogen bond action in a short time in an aqueous solution, and specifically is a mixture of one or more of carboxyl modified bentonite, hydroxyl modified bentonite, amino modified hydrotalcite and carboxyl modified hydrotalcite; the carboxyl group-modified bentonite is preferred. The preferred weight ratio of the hydrogen bond thixotropic agent is 1-3 parts.

Further, the preparation method of the carboxyl modified bentonite comprises the following steps:

firstly, 100g of polyacrylic acid dispersant is added into 1kg of deionized water, and the mixture is stirred for 10min until the mixture is uniformly mixed;

heating the solution to 60 ℃, gradually adding 200g of sodium bentonite within 10min at the rotating speed of 100r/min, then starting high-speed homogeneous stirring for 4000r/min, and carrying out homogeneous stirring for 60min to prepare carboxyl modified bentonite gel;

adding 200g of the modified bentonite gel into 1kg of absolute ethyl alcohol, uniformly stirring, performing suction filtration by using filter paper, and drying a filter cake at 60 ℃ to prepare the carboxyl modified bentonite.

Further, the preparation method of the hydroxyl modified bentonite comprises the following steps:

firstly, 100g of polyethylene glycol PEG400 is added into 1kg of deionized water, and the mixture is stirred for 10min until the mixture is uniformly mixed;

heating the solution to 60 ℃, gradually adding 200g of sodium bentonite within 10min at the rotating speed of 100r/min, then starting high-speed homogeneous stirring for 4000r/min, and carrying out homogeneous stirring for 60min to prepare carboxyl modified bentonite gel;

adding 200g of the modified bentonite gel into 1kg of absolute ethyl alcohol, uniformly stirring, performing suction filtration by using filter paper, and drying a filter cake at 60 ℃ to prepare the carboxyl modified bentonite.

Further, amino-modified bentonite:

firstly, 100g of isopropanolamine is added into 1kg of deionized water, and the mixture is stirred for 10min until the mixture is uniformly mixed.

Heating the solution to 60 ℃, gradually adding 200g of sodium bentonite within 10min at the rotating speed of 100r/min, then starting high-speed homogeneous stirring for 4000r/min, and carrying out homogeneous stirring for 60min to prepare carboxyl modified bentonite gel;

adding 200g of the modified bentonite gel into 1kg of absolute ethyl alcohol, uniformly stirring, performing suction filtration by using filter paper, and drying a filter cake at 60 ℃ to prepare the carboxyl modified bentonite.

Further, the preparation method of the amino modified hydrotalcite comprises the following steps:

200g of deionized water solution A (0.06M Mg (NO)₃)₂6H₂O and 0.03MAL (NO)₃)₃·9H₂O) and 300g of deionized water solution B (0.18M NaOH) are simultaneously added into a colloid mill to be rapidly sheared for 1min at 4000r/min, then the mixture is placed into a reaction kettle to be hermetically reacted for 24 hours at 110 ℃ to prepare a stable hydrotalcite nano colloid solution with uniform particle size, the hydrotalcite nano colloid solution is washed by deionized water and centrifuged for several times to remove unreacted ionic impurities, and the hydrotalcite nano sheets are prepared by drying at 100 ℃ after suction filtration;

adding 20g of the hydrotalcite nano-sheets into 100g of deionized water, stirring for 10min, and uniformly mixing;

adding 10g triethanolamine continuously, stirring for 1h at 80 ℃ to prepare amino modified hydrotalcite, washing with deionized water, centrifuging for several times to remove unreacted triethanolamine, filtering, and drying at 100 ℃ to obtain amino modified hydrotalcite.

Further, the preparation method of the carboxyl modified hydrotalcite comprises the following steps:

200g of deionized water solution A (0.06M Mg (NO)₃)₂6H₂O and 0.03MAL (NO)₃)₃·9H₂O) and 300g of deionized water solution B (0.18M NaOH) are simultaneously added into a colloid mill to be rapidly sheared for 1min at 4000r/min, then the mixture is placed into a reaction kettle to be hermetically reacted for 24 hours at 110 ℃ to prepare a stable hydrotalcite nano colloid solution with uniform particle size, the hydrotalcite nano colloid solution is washed by deionized water and centrifuged for several times to remove unreacted ionic impurities, and the hydrotalcite nano sheets are prepared by drying at 100 ℃ after suction filtration;

adding 20g of the hydrotalcite nano-sheets into 100g of deionized water, stirring for 10min, and uniformly mixing;

continuously adding 10g of polyacrylic acid, stirring for 1h at 80 ℃ to prepare amino modified hydrotalcite, washing with deionized water, centrifuging for several times to remove unreacted polyacrylic acid, filtering, and drying at 100 ℃ to prepare amino modified hydrotalcite.

Further, the suspension synergist is one or more of polyether polyol, polymeric polyether, polymeric polyester, polyvinylamine, polypropylene imine and polyvinyl alcohol, preferably polyether polyol. The preferred weight ratio of the suspending synergist is 3-5 parts.

Further, the charge neutralizer is a mixture of one or more of cocamidopropyl betaine, cocoyl dimethylamine oxide, tetradecylamine, hexadecylamine, cocoyl fatty amine, and octadecyl dimethyl benzyl ammonium chloride. The charge neutralizer is preferably present in an amount of 0.1 to 0.5 parts by weight.

Further, the dispersing agent is one or more of polyacrylate, polyurethane, alkoxy polymer and polypropylene-polyphosphate block copolymer, and preferably polyacrylate ammonium salt. The preferable weight ratio of the dispersant is 5-10 parts.

Further, the lubricant is one or more of ethylene glycol, polyethylene glycol, glycerol, isohexane glycol and propylene glycol, preferably isohexane glycol. The preferred weight ratio of the lubricant is 15-20 parts.

Further, the antirust agent is one or more of lauric acid, isomeric dodecanoic acid, polyaspartic acid, amino acid, sebacic acid, caprylic acid and polycarboxylic acid. The weight ratio of the antirust agent is preferably 0.1-0.3 part.

Further, the weight ratio of the water is 63.4-83.5 parts.

The invention also discloses a preparation method of the suspension auxiliary agent applied to large-size silicon wafer grinding, which comprises the following steps:

sequentially adding a dispersing agent, a lubricating agent, a charge neutralizing agent and an antirust agent into deionized water under the stirring condition, and stirring for 30-60min, preferably 30-40min until the materials are uniformly mixed;

step (2) heating the solution obtained in the step (1) to 40-50 ℃, preferably 40-45 ℃, continuously stirring at the high speed of 1500-;

and (3) under the condition of low-speed stirring at 50-100r/min, preferably 80-100r/min, adding the suspension synergist into the solution obtained in the step (2) twice, and stirring for 30-60min, preferably 30-40min until the suspension synergist is uniformly mixed to prepare the suspension assistant applied to grinding of large-size silicon wafers.

The invention also discloses the application of the suspension auxiliary agent applied to the grinding of the large-size silicon wafer in the field of grinding liquid, wherein the addition proportion of the suspension auxiliary agent accounts for 2-5 wt% of the grinding liquid.

Compared with the prior art, the suspension auxiliary agent applied to large-size silicon wafer grinding and the preparation method thereof have the following advantages:

1) this application silicon chip grinds suspension auxiliary agent, through hydrogen bond thixotropic agent and suspension synergist combined action, form compact hydrogen bond grid structure in grinding liquid system, have higher resistant shearing effect, it is more stable to form the hydrogen bond effect, the abrasive material to unidimensional and appearance has better suspension nature, effectively avoid grinding in-process grinding and the coagulation of broken fine abrasive material, a grinding for jumbo size monocrystalline silicon piece, have higher grinding rate, reduce the loss layer of silicon chip simultaneously, promote grinding quality.

2) The charge neutralizer that this application adopted contains the material that amino structure area positive charge, can effectively eliminate the unnecessary negative charge on broken nanometer level abrasive dust surface, can form fibrous conductive network inside the solution, can derive the static charge of nanometer level abrasive dust surface accumulation, the electric charge on the various surfaces of continuous elimination, avoid electrostatic adsorption reunion, polymerization dispersant high efficiency adsorbs and twines on abrasive dust and miropowder surface simultaneously, form stable steric hindrance, and can keep compound abrasive material to have soft structure for a long time, avoid forming hard sediment in the pipeline transportation, promote grinding efficiency and production efficiency.

In conclusion, the suspension auxiliary agent can effectively improve the suspension performance of the composite abrasive, has good dispersibility for different abrasives, avoids abrasive agglomeration and abrasive hard precipitation formed in circular grinding, can enable the abrasives to be uniformly distributed on a grinding disc, enables all parts of a silicon wafer to be stressed more uniformly in grinding, improves the precision of silicon wafer grinding dust, is suitable for grinding large-size silicon wafers, and is particularly suitable for grinding 8-inch and 12-inch monocrystalline silicon wafers.

Drawings

FIG. 1 shows the silicon wafer surface condition under the dark field of a microscope after the silicon wafer is ground by using the suspending aid of example 1.

FIG. 2 shows the surface condition of the silicon wafer in dark field of a microscope after the silicon wafer is ground by using the suspending aid of comparative example 1.

FIG. 3 shows the surface condition of the silicon wafer in dark field of the microscope after the silicon wafer is ground by using the suspending aid of comparative example 2.

Detailed Description

The invention is further illustrated by the following examples:

example 1:

the suspension aid applied to grinding of large-size silicon wafers in the embodiment is composed of the following components (by weight):

carboxyl modified bentonite: 1 part;

polyether polyol: 5 parts of a mixture;

cocamidopropyl betaine: 0.1 part;

polyacrylic acid ammonium salt: 5 parts of a mixture;

isohexide: 15 parts of (1);

sebacic acid: 0.3 part;

deionized water: 73.6 parts;

the preparation method of the carboxyl modified bentonite comprises the following steps: firstly, 100g of polyacrylic acid dispersant is added into 1kg of deionized water, and the mixture is stirred for 10min until the mixture is uniformly mixed; heating the solution to 60 ℃, gradually adding 200g of sodium bentonite within 10min at the rotating speed of 100r/min, then starting high-speed homogeneous stirring for 4000r/min, and carrying out homogeneous stirring for 60min to prepare carboxyl modified bentonite gel; adding 200g of the modified bentonite gel into 1kg of absolute ethyl alcohol, uniformly stirring, performing suction filtration by using filter paper, and drying a filter cake at 60 ℃ to prepare the carboxyl modified bentonite.

The preparation method of the suspension aid applied to large-size silicon wafer grinding comprises the following steps:

sequentially adding a dispersing agent, a lubricating agent, a charge neutralizing agent and an antirust agent into deionized water under the stirring condition, and stirring for 30min until the materials are uniformly mixed;

step (2) heating the solution obtained in the step (1) to 40 ℃, adding a hydrogen bonding thixotropic agent under continuous stirring at 1500rpm, stirring for 20min until a uniform emulsion is formed, stopping high-speed stirring, and standing the emulsion for swelling and stabilizing for more than 1 hour;

and (3) adding the suspension synergist into the solution obtained in the step (2) under the low-speed stirring condition of 100r/min, and stirring for 40min until the suspension synergist is uniformly mixed to prepare the suspension aid applied to grinding of large-size silicon wafers.

Examples 2 to 10, comparative examples 1 to 3

The compositions and weight ratios of examples 2 to 10 and comparative examples 1 to 3 are shown in Table 1, and the preparation method thereof is the same as example 1.

Table 1 shows the components and weight ratios of the suspension aid applied to grinding of large-size silicon wafers in examples 2 to 10 to the suspension aid applied in comparative examples 1 to 3.

The analytical test methods of the examples are as follows:

grinding tests were performed on the suspension aids prepared in examples 1 to 10 and comparative examples 1 to 3 using 12-inch single-crystal silicon wafers, and the removal rate, TTV, depth of damaged layer, surface roughness, and surface fouling rate were compared; meanwhile, the suspension auxiliary agent and the composite grinding sand are subjected to a suspension settlement experiment, and the settlement hardness of the composite grinding sand after the different suspension auxiliary agents are used for preparing the liquid for 24 hours is compared.

Performance test I surface fouling evaluation: when the silicon wafer is cleaned after grinding, whether the surface has abrasive dust or other residues is observed under a microscope, if no residues exist, the mark is good, and if the residues exist, the mark is poor.

Performance test II evaluation of sedimentation hardness: and (3) standing 100mL of prepared grinding fluid in a measuring cylinder, standing for 24h, and inserting the same glass rod into the grinding sand, wherein the soft sedimentation is realized if the glass rod can be easily inserted, and the hard sedimentation is realized if the glass rod cannot be inserted.

Grinding equipment: the creek well 32B mill,

silicon wafer size: 12 inches;

number of test pieces: 2400 pieces;

rotating speed: 30 r/min;

pressure: 150g/cm²；

Temperature of the dish surface: 40-50 ℃;

flow rate: 1.5L/min;

grinding time: and (3) 30 min.

The proportion of the grinding fluid is that water, a suspension auxiliary agent and composite grinding sand Fujimi1200 is 50:1.8:20 (mass ratio).

TABLE 2 grinding results of grinding liquids formulated with suspension aids according to examples 1 to 10 and comparative examples 1 to 3

Through the comparison of the grinding technical data of the 12-inch monocrystalline silicon wafer, the removal rate, the silicon wafer surface roughness, the TTV, the depth of a damaged layer and other technical parameters of examples 1-10 of the invention are proved to be superior to those of comparative examples 1, 2 and 3, the sedimentation hardness of the grinding sand is very soft after 24h of standing time, no hard precipitate is formed, the production is more convenient, and the cleaning capability is obviously superior to that of comparative examples 1, 2 and 3.

FIG. 1 shows the surface uniformity and no scratch of the silicon wafer surface under the dark field of the microscope after the silicon wafer is ground by using the suspending aid of example 1. FIG. 2 shows the condition of a scratch on the surface of a silicon wafer under a dark field of a microscope after the silicon wafer is ground by using the suspending aid of the comparative example 1. FIG. 3 shows the surface condition of a deep scratch on the silicon wafer in a dark field of a microscope after the silicon wafer is ground by using the suspending aid of the comparative example 2. Therefore, the suspension auxiliary agent applied to large-size silicon wafer grinding can effectively improve the suspension performance of the composite grinding material, avoid the formation of grinding material agglomeration and grinding material hard precipitation in the circulating grinding process, ensure that the grinding material is uniformly distributed on a grinding disc, ensure that all parts of a silicon wafer are stressed more uniformly in the grinding process, and improve the precision of silicon wafer grinding dust.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.