Controlled-viscosity CMP casting method

Patent metadata

Field	Value
Publication number	US-9452507-B2
Application number	US-201414576896-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Dec 19, 2014
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

The invention provides a method of manufacturing a polishing pad suitable for planarizing at least one of semiconductor, optical and magnetic substrates. The method obtains a liquid polyurethane material formed from an isocyanate-terminated molecule and a curative agent. The liquid polyurethane material contains 4.2 to 7.5 weight percent fluid-filled polymeric microspheres in the isocyanate-terminated molecule. The fluid-filled polymeric microspheres are a blend of preexpanded and unexpanded fluid-filled polymeric microspheres. The liquid polyurethane material contains a blend of preexpanded and unexpanded fluid-filled polymeric microspheres having a relative viscosity
μ μ 0
of 1.1 to 7. Then the liquid polyurethane material solidifies into a polyurethane matrix that contains preexpanded and expanded fluid-filled polymeric microsphere for forming the polishing pad.

First claim

The invention claimed is:

1. A method of manufacturing a polishing pad suitable for planarizing at least one of semiconductor, optical and magnetic substrates, the method comprising the following:
obtaining a liquid polyurethane material formed from an isocyanate-terminated molecule and a curative agent, the liquid polyurethane material having a
T gel temperature and containing 4.2 to 7.5 weight percent fluid-filled polymeric microspheres in the isocyanate-terminated molecule, the fluid-filled polymeric microspheres are a blend of preexpanded and unexpanded fluid-filled polymeric microspheres, the preexpanded and unexpanded fluid-filled polymeric microspheres each having a T start temperature where diameter of the preexpanded and unexpanded fluid-filled polymeric microspheres increases at temperatures equal to or above the T start temperature, with the T start temperature of the unexpanded fluid-filled polymeric microspheres being at least 5° C. less than the T gel temperature of the liquid polyurethane material;

casting the liquid polyurethane material containing the blend of preexpanded and unexpanded fluid-filled polymeric microspheres, the liquid polyurethane material containing the blend of preexpanded and unexpanded fluid-filled polymeric microspheres having a relative viscosity

μ

μ
0

of 1.1 to 7, wherein

μ

μ
0

=

1
+

2.5
⁢
ϕ

+

10.05
⁢

ϕ
2

+

0.00273
⁢

ⅇ

16.6
⁢
ϕ

where μ is the viscosity of the filled system, μ 0 the viscosity of the unfilled material,

μ

μ
0

the relative viscosity, and Φ the volume fraction of the filler;
heating and curing the liquid polyurethane material and the blend of prexpanded and unexpanded fluid-filled polymeric microspheres to a temperature of at least T start of the unexpanded fluid-filled polymeric microspheres to increase the diameter of the unexpanded fluid-filled polymeric microspheres and to form a blend of preexpanded and expanded fluid-filled polymeric microspheres in the liquid polyurethane material and then solidify the liquid polyurethane material into a polyurethane matrix containing the preexpanded and expanded fluid-filled polymeric microspheres; and
forming the polishing pad from the polyurethane matrix containing the preexpanded and expanded fluid-filled polymeric microspheres.

2. The method of claim 1 including the additional step of mixing the blend of preexpanded and unexpanded fluid-filled polymeric microspheres in the liquid polyurethane material before casting.

3. The method of claim 1 wherein the casting is into a cake mold to form a polyurethane cake structure; and including the additional steps of removing the polyurethane cake structure from the mold and skiving the cake structure into multiple polyurethane sheets; and the forming the polishing pads is from the polyurethane sheets.

4. The method of claim 1 wherein the casting includes pouring the liquid polyurethane material and the blend of preexpanded and expanded fluid-filled polymeric microspheres around a transparent block and the forming the polishing pad includes a transparent window in the polishing pad.

5. A method of manufacturing a polishing pad suitable for planarizing at least one of semiconductor, optical and magnetic substrates, the method comprising the following:
obtaining a liquid polyurethane material formed from an isocyanate-terminated molecule and a curative agent, the liquid polyurethane material having a
T gel temperature and containing 4.2 to 7.5 weight percent fluid-filled polymeric microspheres in the isocyanate-terminated molecule, the fluid-filled polymeric microspheres are a blend of preexpanded and unexpanded fluid-filled polymeric microspheres filled with isobutane, isopentane or a mixture of isobutane and isopentane, the preexpanded and unexpanded fluid-filled polymeric microspheres each having a T start temperature where diameter of the preexpanded and unexpanded fluid-filled polymeric microspheres increases at temperatures equal to or above the T start temperature, with the T start temperature of the unexpanded fluid-filled polymeric microspheres being at least 5° C. less than the T gel temperature of the liquid polyurethane material;

casting the liquid polyurethane material containing the blend of preexpanded and unexpanded fluid-filled polymeric microspheres, the liquid polyurethane material containing the blend of preexpanded and unexpanded fluid-filled polymeric microspheres having a relative viscosity

μ

μ
0

of 1.1 to 7, wherein

μ

μ
0

=

1
+

2.5
⁢
ϕ

+

10.05
⁢

ϕ
2

+

0.00273
⁢

ⅇ

16.6
⁢
ϕ

where μ is the viscosity of the filled system, μ 0 the viscosity of the unfilled material,

μ

μ
0

the relative viscosity, and Φ the volume fraction of the filler;
heating and curing the liquid polyurethane material and the blend of prexpanded and unexpanded fluid-filled polymeric microspheres to a temperature of at least T start of the unexpanded fluid-filled polymeric microspheres to increase the diameter of the unexpanded fluid-filled polymeric microspheres and to form a blend of preexpanded and expanded fluid-filled polymeric microspheres in the liquid polyurethane material and then solidify the liquid polyurethane material into a polyurethane matrix containing the preexpanded and expanded fluid-filled polymeric microspheres; and
forming the polishing pad from the polyurethane matrix containing the preexpanded and expanded fluid-filled polymeric microspheres.

Assignees

• Rohm & Haas Elect Materials Cmp Holdings Inc
• Dow Global Technologies Llc

Inventors

• Qian Bainian
• Jacob George C

Classifications

• C08G18/7621

  being toluene diisocyanate including isomer mixtures · CPC title

• C08G18/3243

  containing two or more aromatic rings · CPC title

• B29C39/006 Primary

  Monomers or prepolymers (by reaction injection moulding B29C67/246) · CPC title

• B29K2075/00

  Use of {PU, i.e.} polyureas or polyurethanes {or derivatives thereof}, as moulding material · CPC title

• C08G18/4854

  Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group · CPC title