Methods of manufacturing printed wire boards

Patent metadata

Field	Value
Publication number	US-11337309-B2
Application number	US-202016814222-A
Country	US
Kind code	B2
Filing date	Mar 10, 2020
Priority date	Mar 11, 2019
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

Disclosed herein is a method of forming vias in electrical laminates comprising laminating a sheet having a layer comprising a crosslinkable polymer composition to a substrate wherein the crosslinkable polymer composition has a viscosity at lamination temperatures in the range of 200 Pa-s to 100,000 Pa-s, forming at least one via in the crosslinkable polymer layer by laser ablation; and after the forming of the at least one via, thermally curing the crosslinkable polymer layer. According to certain embodiments the cross linkable polymer composition has a viscosity at lamination temperature of at least 5000 Pa-s. This method yields good lamination results, good via profiles, and good desmear results when such compositions are used and the via is laser ablated before cure.

First claim

What is claimed is:

1. A method comprising:
laminating a sheet having a layer comprising a crosslinkable polymer composition to a substrate wherein the crosslinkable polymer composition has a viscosity at lamination temperatures in a range of 200 Pa-s to 100,000 Pa-s and wherein the crosslinkable polymer composition comprises a crosslinkable polymer having a weight average molecular weight in a range of 30,000 to 150,000 g/mol,
forming at least one via in the crosslinkable polymer composition layer by laser ablation; and
after the forming of the at least one via, curing the crosslinkable polymer composition layer.

2. The method of claim 1 , wherein the laminating occurs at a temperature of 90 to 135° C. and the curing occurs at a temperature of 140 to 200° C.

3. The method of claim 1 , wherein the cross-linkable polymer composition has a minimum viscosity of at least 1000 Pa-s in the temperature range of 100 to 160° C.

4. The method of claim 1 , wherein the viscosity at lamination temperatures is in the range of 5000 Pa-s to 60,000 Pa-s.

5. The method of claim 1 , wherein the crosslinkable polymer composition comprises a crosslinkable polymer which is a reaction product of a reaction mixture comprising at least one addition polymerizable arylcyclobutene monomer.

6. The method of claim 5 wherein the at least one addition polymerizable arylcyclobutene monomer has a structure (1) or (2) or a combination of monomers of structure (1) and/or (2) is used

wherein K is a covalent bond or a divalent group chosen from a C1 to C6 alkyl substituted or unsubstituted divalent aryl group, a C1 to C6 alkyl substituted or unsubstituted divalent heteroaryl group, such as an aryloxy group; a C1 to C30 divalent alkyl group; a C1 to C36 heteroatom containing alkyl group; a divalent C1 to C30 alkylene group, a carbonyl group, an ether group, a thioether group, an ester group, or a cyano group; M is an aromatic group chosen from a C1 to C6 alkyl substituted or unsubstituted divalent aryl group, a C1 to C6 alkyl substituted or unsubstituted divalent heteroaryl group; and L 1 is selected from a covalent bond or is a hydrocarbon linking group having a valence of x+1, preferably, when x is 1, L 1 is divalent hydrocarbon group, such as an alkylene group or an alkyl substituted alkylene group, a C1 to C30 heteroatom containing hydrocarbon group, or a C1 to C30 substituted heterohydrocarbyl group; and R 1 through R 7 are each independently selected from a monovalent group chosen from hydrogen, deuterium, halogen, a C1 to C6 alkyl group, a C1 to C6 alkoxy group, a C1 to C6 alkyl substituted hydrocarbon group, a heteroatom containing hydrocarbon group, a C1 to C6 alkyl substituted heterohydrocarbon group, a cyano group, a C6 to C12 aryl group, a C1 to C6 alkyl substituted aryl group, a heteroaryl group, or a C1 to C6 alkyl substituted heteroaryl group, wherein at least one of R 1 , R 2 , R 3 , and R 4 is chosen from a C1 to C6 alkyl group, a C1 to C6 alkoxy group, a C1 to C6 alkyl substituted hydrocarbon group, a heteroatom containing hydrocarbon group, a C1 to C6 alkyl substituted heterohydrocarbon group, a cyano group, a C6 to C12 aryl group, C1 to C6 alkyl substituted aryl group, a heteroaryl group, or a C1 to C6 alkyl substituted heteroaryl group; and, x and y are each independently an integer from 1 to 5 wherein y is 1 when L 1 is a covalent bond.

7. The method of claim 6 , wherein the reaction mixture further comprises a monomer selected from the group consisting of benzocyclobutene (BCB) containing crosslinkers; allyl methacrylate; divinyl benzene; dienes; allyloxystyrene; vinyl, allyl, or maleimide terminated polyols; polysiloxanes; or maleimide terminated polyimides.

8. The method of claim 5 , wherein the reaction mixture further comprises a second aromatic addition polymerizable monomer selected from the group consisting of styrene, α-methyl styrene, allyloxystyrene, allyl terminated polyarylene ethers or maleimide terminated polyarylene ethers.

9. The method of claim 5 , wherein the reaction mixture further comprises an addition polymerizable third monomer selected from the group consisting of acrylates or methacrylates; maleimides and bis-maleimides; cyclic anhydrides; allyl group containing monomers; linear and branched alkenes.

10. The method of claim 1 , wherein the crosslinkable polymer composition further comprises one or more of a crosslinker, an antioxidant, an inorganic filler, a flow modifier, an adhesion promoter, and a flame retardant.

11. The method of claim 1 , wherein the layer comprising the crosslinkable polymer composition is on a carrier layer.

12. The method of claim 11 , wherein the carrier layer is not removed prior to the laser ablation.

13. The method of claim 11 , wherein the layer comprising the crosslinkable polymer composition is coated on the carrier layer from a solvent and heated to remove at least some of the solvent.

14. The method of claim 11 , wherein the via has a dimension defining an open space at a bottom of the via which is at least 70% of a dimension at the top of the via defining an open space.

15. The method of claim 11 , wherein the laminating and forming vias are repeated before the curing is conducted.

Assignees

• Rohm & Haas Elect Mat

Inventors

• Aoude Tina
• Fleming David
• Riener Michelle Bowerman
• Hayes Colin O'Mara
• Lei Herong
• Barr Robert K
• Danza David Louis

Classifications

• H05K1/0373

  containing additives, e.g. fillers (H05K1/036 takes precedence) · CPC title

• H05K1/0346

  containing N · CPC title

• C08F212/08

  Styrene · CPC title

• C08F212/32

  containing two or more rings · CPC title

• H05K3/4069 Primary

  for via connections in organic insulating substrates · CPC title