REDUCING JOINT EMBRITTLEMENT IN LEAD-FREE SOLDERING PROCESSES
First Claim
Patent Images
1. A method of forming a solder joint, comprising:
- (a) providing a lead-free, tin-containing solder alloy;
(b) providing a printed wiring board substrate or a ball grid array substrate, said substrate being formed from a material comprising copper, optionally also zinc, and one or more of Ni, Co, Cr, Mn, Zr, Fe and Si and/or alloys thereof;
(c) heating the solder alloy; and
(d) either before, during or after step (c) contacting the solder alloy with the substrate.
7 Assignments
0 Petitions
Accused Products
Abstract
In the manufacture of products such as printed wiring boards or chip scale packaging and ball grid arrays, incorporating one or more elements selected from among Ni, Co, Cr, Mn, Zr, Fe and Si into a lead-free soldering process to reduce joint embrittlement. In varied embodiments this is accomplished by spraying onto a solder sphere or preform surface, by spraying onto a device substrate surface, or by incorporating into the device substrate alloy.
34 Citations
20 Claims
-
1. A method of forming a solder joint, comprising:
-
(a) providing a lead-free, tin-containing solder alloy; (b) providing a printed wiring board substrate or a ball grid array substrate, said substrate being formed from a material comprising copper, optionally also zinc, and one or more of Ni, Co, Cr, Mn, Zr, Fe and Si and/or alloys thereof; (c) heating the solder alloy; and (d) either before, during or after step (c) contacting the solder alloy with the substrate. - View Dependent Claims (2)
-
-
3. A method of forming a solder joint, comprising:
-
(a) providing a lead-free, tin-containing solder alloy; (b) providing a printed wiring board substrate or a ball grid array substrate, said substrate being formed from a material comprising copper and optionally also zinc; (c) depositing one or more of Ni, Co, Cr, Mn, Zr, Fe and Si and/or alloys thereof on a surface of the substrate; (d) heating the solder alloy; and (e) either before, during or after step (d) contacting the solder alloy with said surface of the substrate. - View Dependent Claims (4, 5, 6)
-
-
7. A method of forming a solder joint, comprising:
-
(a) providing a lead-free, tin-containing solder alloy; (b) forming the solder alloy into spheres or other preforms; (c) depositing on the surface of the spheres or other preforms one or more of Ni, Co, Cr, Mn, Zr, Fe and Si and/or an alloy thereof; (d) providing a printed wiring board substrate or a ball grid array substrate, said substrate being formed from a material comprising copper and optionally also zinc; (e) heating the solder alloy spheres or other preforms; and (f) either before, during or after step (e) contacting the solder alloy with said surface of the substrate. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
- 18. A lead-free, tin-containing solder alloy in the form of spheres or preforms, wherein an outer surface of the spheres or performs has deposited thereon one or more of Ni, Co, Cr, Mn, Zr, Fe and Si and/or an alloy of any one or more thereof.
Specification