CN-122011326-A - Preparation method of solvent-free polyurethane grinding pad with color change monitoring function

CN122011326ACN 122011326 ACN122011326 ACN 122011326ACN-122011326-A

Abstract

The invention provides a preparation method of a solvent-free polyurethane grinding pad with a color change monitoring function, which comprises the following steps of dissolving a PH indicator, an emulsifier and a chain extender in deionized water to prepare a water phase, dissolving wall material monomers in an organic solvent to prepare an oil phase, adding an amino silicone oil coupling agent, adding the water phase into the oil phase to carry out emulsification and interfacial polymerization reaction to obtain a PH indicator microcapsule, taking a component A polyol, a filler, a catalyst and the PH indicator microcapsule, firstly adding the filler into the component A polyol to mix, then adding the catalyst to mix, finally adding the PH indicator microcapsule to obtain a material A, taking a component B isocyanate as a material B, stirring and mixing the material A and the material B in the presence of supercritical CO 2 fluid to obtain a mixture, heating, curing, cooling, separating release paper and cutting to obtain the solvent-free polyurethane grinding pad. The invention reduces the breakage rate of the microcapsule, and the microcapsule is uniformly dispersed without agglomeration.

Inventors

CHEN QIAN
YAN XUEFENG
FU PENGFEI
HU LIZHEN
WU HAO
ZHOU SHAOFENG
HONG BIN

Assignees

浙江禾欣新材料有限公司

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (9)

1. The preparation method of the solvent-free polyurethane polishing pad with the color change monitoring function is characterized by comprising the following steps of: S1, dissolving a PH indicator, an emulsifier and a chain extender in deionized water to prepare a water phase, dissolving wall material monomers in an organic solvent to prepare an oil phase, adding an amino silicone oil coupling agent into the oil phase or the water phase, adding the water phase into the oil phase under a shearing condition to carry out emulsification and interfacial polymerization reaction, and solidifying, washing and drying to obtain the PH indicator microcapsule; s2, taking 100 parts of the A-component polyol, 0-30 parts of filler, 0.01-1 part of catalyst and 1-20 parts of the PH indicator microcapsule prepared in the step S1 by weight, adding the filler into the A-component polyol, mixing, adding the catalyst, mixing, finally adding the PH indicator microcapsule, and uniformly dispersing under mechanical stirring to obtain a material A; S3, taking 50-120 parts of isocyanate of the component B as a material B, respectively conveying the material A and the material B to a mixing machine head, simultaneously conveying supercritical CO 2 fluid into the mixing machine head according to a given proportion, and stirring and mixing the material A and the material B under the condition that the supercritical CO 2 fluid exists to obtain a mixture; and S4, coating the mixture obtained in the step S3 on release paper, heating, curing, cooling, separating the release paper and cutting to obtain the solvent-free polyurethane polishing pad.
2. The preparation method of the solvent-free polyurethane polishing pad with the color change monitoring function according to claim 1 is characterized in that in the step S1, the water phase is 100 parts by weight of deionized water, 0.5-5 parts by weight of a PH indicator and 0.1-5 parts by weight of an emulsifier, the PH indicator is one or more of phenolphthalein, methyl red and bromothymol blue, the chain extender is at least one of hexamethylenediamine and diethylenetriamine, and the molar ratio of the chain extender to wall material monomers is 1:1-1:1.5.
3. The preparation method of the solvent-free polyurethane polishing pad with the color change monitoring function according to claim 1 is characterized in that in the step S1, the oil phase is prepared from 100 parts by weight of an organic solvent and 5-20 parts by weight of wall material monomers, wherein the wall material monomers are selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate.
4. The method for preparing a color-change monitoring solvent-free polyurethane polishing pad according to claim 1, wherein in the step S1, the amino silicone oil coupling agent is added in an amount of 0.1-2 parts by weight.
5. The method for preparing a solvent-free polyurethane polishing pad with color change monitoring function according to claim 1, wherein in the step S1, the technological conditions of the emulsification and interfacial polymerization reaction are that shearing emulsification is carried out at a rotation speed of 2000-6000rpm to form water-in-oil emulsion, then the speed is reduced to 200-500rpm, and the polymerization reaction is carried out at a temperature of 65-70 ℃ for 2-3 hours.
6. The method for preparing the solvent-free polyurethane polishing pad with the color change monitoring function according to claim 1, wherein in the step S2, the A-component polyol is selected from polyether polyol or polyester polyol, and the filler is selected from one or more of matting powder, aluminum hydroxide, aluminum oxide, magnesium hydroxide, zinc borate, aluminum silicate, magnesium carbonate, glass beads, white carbon black, silicone resin micropowder, silicon dioxide, calcium carbonate, magnesium oxide, cerium oxide and zirconium oxide.
7. The method for preparing a solvent-free polyurethane polishing pad with color change monitoring function according to claim 1, wherein in the step S2, the mechanical stirring process conditions after the PH indicator microcapsules are added are that the rotating speed is 300-600rpm, and the stirring time is 10-20 minutes.
8. The method for preparing a solvent-free polyurethane polishing pad with color change monitoring function according to claim 1, wherein in the step S3, the B-component isocyanate is diphenylmethane diisocyanate.
9. The method for preparing a color-change monitoring solvent-free polyurethane polishing pad as claimed in claim 1, wherein in the step S4, the coating amount is controlled to be 100-300g/m 2 , and the viscosity of the mixture is 2000-10000cps at 25 ℃.

Description

Preparation method of solvent-free polyurethane grinding pad with color change monitoring function Technical Field The invention relates to a preparation method of a polyurethane grinding pad, in particular to a preparation method of a solvent-free polyurethane grinding pad with a color change monitoring function, and belongs to the technical field of polyurethane materials. Background Chemical Mechanical Polishing (CMP) is a key process for planarizing the surface of a semiconductor wafer, and the performance of a polishing pad, which is a core consumable material for CMP, directly determines the polishing effect. With the increase of the service time, the surface of the polishing pad is worn, so that the depth of the groove becomes shallow, the polishing liquid conveying capability is reduced, and the wafer yield is further affected. Therefore, it is important to accurately judge the abrasion degree of the polishing pad in time and replace the polishing pad. The existing polishing pad life detection mainly depends on off-line measurement or experience estimation, and no visual real-time monitoring means is available. Although the prior art has a dye or indicator added to the polishing pad, the directly mixed dye does not show the depth information of abrasion. To address this problem, microcapsule technology has been introduced in an attempt to indicate wear by encapsulating a PH indicator, where the microcapsules rupture during milling and are discolored by alkaline/acidic polishing solutions. In the preparation of the solvent-free polyurethane polishing pad by applying the microcapsule technology, the problems of difficult combination of microcapsule dispersibility and low breakage and poor interfacial bonding force between the microcapsule wall material and the solvent-free polyurethane matrix are generally faced. The viscosity of the solvent-free polyurethane component, particularly the polyol a component, is relatively high, typically above 2000cps, and high shear mechanical agitation is typically required to uniformly disperse the microcapsules in the matrix. However, the microcapsule wall material of micron order is thin and brittle, and the high shearing force is very easy to cause the microcapsule to break and lose efficacy in the mixing stage, so that the finished product of the grinding pad is discolored or loses monitoring function before being used. If the stirring speed is reduced, the microcapsules are liable to agglomerate, resulting in uneven polishing pad performance. Interface defects often exist between microcapsule wall materials and solvent-free polyurethane matrixes, and in the high-strength shearing and grinding process of CMP, the microcapsules are integrally fallen off due to weak interface binding force, larger pits are formed, the indication function is lost, and fallen particles can scratch the surface of a wafer. Disclosure of Invention Based on the background, the invention aims to provide a preparation method of a solvent-free polyurethane grinding pad with a color change monitoring function, which is characterized in that amino silicone oil interface modification is introduced and a plasticizing viscosity reduction effect of a supercritical fluid is utilized, so that the uniform dispersion of the polyurethane grinding pad in a solvent-free system is realized on the premise of ensuring the structural integrity of a microcapsule, and the problems that the microcapsule is easy to damage and has poor bonding force with a matrix in the preparation process in the prior art are solved. In order to achieve the above object, the present invention provides the following technical solutions: A preparation method of a solvent-free polyurethane grinding pad with a color change monitoring function comprises the following steps: S1, dissolving a PH indicator, an emulsifier and a chain extender in deionized water to prepare a water phase, dissolving wall material monomers in an organic solvent to prepare an oil phase, adding an amino silicone oil coupling agent into the oil phase or the water phase, adding the water phase into the oil phase under a shearing condition to carry out emulsification and interfacial polymerization reaction, and solidifying, washing and drying to obtain the PH indicator microcapsule; s2, taking 100 parts of the A-component polyol, 0-30 parts of filler, 0.01-1 part of catalyst and 1-20 parts of the PH indicator microcapsule prepared in the step S1 by weight, adding the filler into the A-component polyol, mixing, adding the catalyst, mixing, finally adding the PH indicator microcapsule, and uniformly dispersing under mechanical stirring to obtain a material A; S3, taking 50-120 parts of isocyanate of the component B as a material B, respectively conveying the material A and the material B to a mixing machine head, simultaneously conveying supercritical CO 2 fluid into the mixing machine head according to a given proportion, and stirring and mixing the material A a