UV-curable resins used for chemical mechanical polishing pads
The invention provides a UV-curable resin for forming a chemical-mechanical polishing pad comprising: (a) one or more acrylate blocked isocyanates; (b) one or more acrylate monomers; and (c) a photoinitiator. The invention also provides a method of forming a chemical-mechanical polishing pad using the UV-curable resin.
1. A UV-curable resin for forming a chemical-mechanical polishing pad comprising:
(a) an acrylate blocked isocyanate component, wherein the acrylate blocked isocyanate component comprises an acrylate blocking agent and an isocyanate terminated urethane prepolymer, wherein the acrylate blocking agents are selected from 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), 2-(tert-butylamino) ethyl methacrylate (TBEMA), and 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHPMA), wherein the acrylate blocking agent and the isocyanate terminated urethane prepolymer form a capped prepolymer, and wherein there is a ratio of particular capped prepolymers in the acrylate blocked isocyanate component;
(b) one or more acrylate monomers; and
(c) a photoinitiator.
2. The UV-curable resin of claim 1 , wherein the acrylate blocked isocyanate component comprises polyisocyanates.
3. The UV-curable resin of claim 1 , wherein the isocyanate-terminated urethane prepolymers comprise aromatic prepolymers, aliphatic prepolymers, or combinations thereof.
4. The UV-curable resin of claim 1 , wherein the acrylate blocking agents forming the capped prepolymers are 2-(tert-butylamino) ethyl methacrylate and 2-hydroxyethyl acrylate.
5. The UV-curable resin of claim 4 , wherein the ratio of 2-(tert-butylamino) ethyl methacrylate capped prepolymers: 2-hydroxyethyl acrylate capped prepolymers is greater than 50:50.
6. The UV-curable resin of claim 5 , wherein the ratio of 2-(tert-butylamino) ethyl methacrylate capped prepolymers: 2-hydroxyethyl acrylate capped prepolymers is 75:25.
7. The UV-curable resin of claim 1 , wherein the one or more acrylate monomers are selected from isobornyl methacrylate (IBMA), 2-carboxyethyl acrylate (CEA), 2-hydroxyethyl acrylate (HEA), ethylene glycol dimethacrylate (EGDMA), neopentyl glycol dimethacrylate (NGDMA), 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHPMA) and trimethylolpropane triacrylate (TMPTA).
8. The UV-curable resin of claim 1 , wherein the photoinitiator is diphenylphosphine oxide (TPO).
9. The UV-curable resin of claim 1 further comprising an additive selected from stabilizers, plasticizers, porogen fillers, pigments and combinations thereof.
10. A chemical-mechanical polishing pad comprising polymerized material formed from polymerization of the UV-curable resin of claim 1 .
11. A method of forming a polishing pad comprising:
(a) preparing a UV-curable resin comprising:
(i) an acrylate blocked isocyanate component, wherein the acrylate blocked isocyanate component comprises an acrylate blocking agent and an isocyanate terminated urethane prepolymer, wherein the acrylate blocking agents are selected from 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), 2-(tert-butylamino) ethyl methacrylate (TBEMA), and 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHPMA), wherein the acrylate blocking agent and the isocyanate terminated urethane prepolymer form a capped prepolymer, and wherein there is a ratio of particular capped prepolymers in the acrylate blocked isocyanate component;
(ii) one or more acrylate monomers, and
(iii) a photoinitiator;
(b) exposing a thin layer of the UV-curable resin to UV light, initiating a polymerization reaction, and thus forming a thin layer of solidified pad material;
wherein the method does not include a thermal curing step.
12. The method of claim 11 , wherein the isocyanate-terminated urethane prepolymers comprise aromatic prepolymers, aliphatic prepolymers, or combinations thereof.
13. The method of claim 11 , wherein the acrylate blocking agents forming the capped prepolymers are 2-(tert-butylamino) ethyl methacrylate and 2-hydroxyethyl acrylate.
14. The method of claim 13 , wherein the ratio of 2-(tert-butylamino) ethyl methacrylate capped prepolymers: 2-hydroxyethyl acrylate capped prepolymers is greater than 50:50.
15. The method of claim 14 , wherein the ratio of 2-(tert-butylamino) ethyl methacrylate capped prepolymers: 2-hydroxyethyl acrylate capped prepolymers is 75:25.
16. The method of claim 11 , wherein the one or more acrylate monomers are selected from isobornyl methacrylate (IBMA), 2-carboxyethyl acrylate (CEA), 2-hydroxyethyl acrylate (HEA), ethylene glycol dimethacrylate (EGDMA), neopentyl glycol dimethacrylate (NGDMA), 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHPMA) and trimethylolpropane triacrylate (TMPTA).
17. The method of claim 11 , wherein he photoinitiator is diphenylphosphine oxide (TPO).
18. The method of claim 11 , further comprising an additive selected from stabilizers, plasticizers, porogen fillers, pigments and combinations thereof.