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, and one or more of Ni, Co, Cr, Mn, Zr, Fe and Si and/or alloys thereof, and optionally also zinc;
(c) heating the solder alloy; and
(d) either before, during or after step (c) contacting the solder alloy with the substrate;
wherein said material of the substrate comprises 95 wt % or more Cu and at least one selected from among 0.04 to 5 wt % Zr, 0.04 to 5 wt % Fe, and 0.04 to 5 wt % Si; and
wherein the substrate is formed from one of the following alloy compositions (wt. %);
Cu-1Zr, Cu-2.35Fe-0.03P-0.12Zn, Cu-1.5Fe-0.18P-0.8Co-0.6Sn, Cu-0.6Fe-0.2P-0.05Mg, Cu-2.8Al-1.8Si-0.4Co, Cu-3.0Ni-0.65Si-0.15Mg, Cu-3.0Si-1.5Sn-0.1Cr.
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.
-
Citations
21 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, and one or more of Ni, Co, Cr, Mn, Zr, Fe and Si and/or alloys thereof, and optionally also zinc; (c) heating the solder alloy; and (d) either before, during or after step (c) contacting the solder alloy with the substrate; wherein said material of the substrate comprises 95 wt % or more Cu and at least one selected from among 0.04 to 5 wt % Zr, 0.04 to 5 wt % Fe, and 0.04 to 5 wt % Si; and wherein the substrate is formed from one of the following alloy compositions (wt. %);
Cu-1Zr, Cu-2.35Fe-0.03P-0.12Zn, Cu-1.5Fe-0.18P-0.8Co-0.6Sn, Cu-0.6Fe-0.2P-0.05Mg, Cu-2.8Al-1.8Si-0.4Co, Cu-3.0Ni-0.65Si-0.15Mg, Cu-3.0Si-1.5Sn-0.1Cr. - View Dependent Claims (4, 5, 7)
-
-
2. A method of forming a solder joint, comprising:
-
(a) providing a lead-free, tin-containing solder alloy , wherein the lead-free, tin-containing solder is essentially free of Ni, Co, Cr, Mn, Zr, Fe and Si; (b) providing a printed wiring board substrate or a ball grid array substrate, said substrate being formed from a material comprising copper, and one or more of Ni, Co, Cr, Mn, Zr, Fe and Si and/or alloys thereof , and optionally also zinc; (c) heating the solder alloy; and (d) either before, during or after step (c) contacting the solder alloy with the substrate; wherein the lead-free, tin-containing solder is based on a Sn-Cu alloy including Ag. - View Dependent Claims (18, 20)
-
-
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 one or more of Ni, Co, Cr, Mn, Zr, Fe and Si and/or alloys thereof, and optionally also zinc; (c) heating the solder alloy; and (d) either before, during or after step (c) contacting the solder alloy with the substrate; wherein said material of the substrate comprises 95 wt % or more Cu and at least one selected from among 0.04 to 5 wt % Zr, 0.04 to 5 wt % Fe, and 0.04 to 5 wt % Si; and wherein the lead-free, tin-containing solder is based on a Sn-Cu alloy including Ag. - View Dependent Claims (6, 8, 19, 21)
-
-
9. A method of forming a solder joint, comprising:
-
(a) providing a lead-free, tin-containing solder alloy based on a Sn-Cu alloy including Ag; (b) providing a printed wiring board substrate or a ball grid array substrate, said substrate being formed from a material comprising copper, and one or more of Ni, Co, Cr, Mn, Zr, Fe and Si and/or alloys thereof, and optionally also zinc; (c) heating the solder alloy; and (d) either before, during or after step (c) contacting the solder alloy with the substrate. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
-
Specification