Claims
- 1. A method of electrically connecting an electrical component having a plurality of spaced apart electrical component electrical terminations to a substrate having a plurality of spaced apart substrate electrical terminations corresponding to the terminations of said electrical component to form a plurality of spaced apart electrical connections and then interfilling said electrical and substrate components with an encapsulant composition sandwiched therebetween to encase said spaced apart electrical connections comprising:a) forming spaced apart electrical connections of said spaced apart component electrical terminations to said corresponding spaced apart substrate electrical terminations with solder at reflow soldering temperature utilizing a cycloaliphatic epoxy-based fluxing agent that leaves a cycloaliphatic epoxy-based fluxing agent residue that is partially cured on said spaced apart electrical connections and leaves open space between the spaced apart electrical connections with cycloaliphatic epoxy-based fluxing agent residue thereon; b) filling said open space between said spaced apart electrical connections with partially cured cycloalinhatic epoxy-based fluxing agent residue thereon with an epoxy underfill encapsulant that co-cures with the cycloaliphatic epoxy-based fluxing agent residue; and then c) co-curing said epoxy underfill encapsulant and cycloaliphatic epoxy-based fluxing agent residue to form a bond at the interface of said epoxy based underfill encapsulant and cycloaliphatic epoxy-based fluxing agent residue.
- 2. The method of claim 1, wherein the cross-linking agent is an esterified anhydride.
- 3. The method of claim 1, wherein the epoxy underfill encapsulant is an anhydride cured epoxy underfill.
- 4. The method of claim 1, wherein the cycloaliphatic epoxy-based fluxing agent further comprises a solvent.
- 5. The method of claim 4, wherein the epoxy-based fluxing agent further comprises an adhesion promoter.
- 6. The method of claim 1, wherein the cycloaliphatic epoxy-based fluxing agent is applied in the form of a thin film of a thickness less than {fraction (10/1000)} inch.
- 7. The method of claim 1, wherein the cycloaliphatic epoxy-based fluxing agent comprises a cycloaliphatic epoxy resin and a cross-linking agent which, when used in combination, provide a level of flux activity to clean the surface metal oxides of the solder used to form said electrical connections and to provide latency during a preselected solder reflow profile.
- 8. The method of claim 7, wherein the cycloaliphatic epoxy-based fluxing agent further comprises a catalyst for catalyzing cross-linking of said cycloaliphatic epoxy resin with said cross-linking agent, the peak exotherm of said mixture of catalyst, thermosetting resin, and cross-linking agent as measured using differential scanning calorimetry at a ramp rate of 10° C. per minute being at or above the solder melting point whereby the gel point of said cycloaliphatic epoxy-based fluxing agent is reached after solder melt.
- 9. The method of claim 1 wherein the cycloaliphatic epoxy-based fluxing agent residue liquifies at dispense and underfill temperature used to fill the open space between spaced apart electrical connections having cycloaliphatic epoxy-based fluxing agent residue thereon with epoxy-based underfill encapsulant.
Parent Case Info
This application is a continuation of U.S. Ser. No. 09/148,506 filed Sep. 4, 1998 now U.S. Pat. No. 6,367,150, issued on Apr. 9, 2002, which claims the benefit of Provisional application Ser. No. 60/057,587, filed Sep. 5, 1997, which U.S. application is hereby incorporated herein by reference.
US Referenced Citations (5)
Number |
Name |
Date |
Kind |
5371404 |
Juskey et al. |
Dec 1994 |
A |
5543585 |
Booth et al. |
Aug 1996 |
A |
5641996 |
Omoya et al. |
Jun 1997 |
A |
5729440 |
Jimarez et al. |
Mar 1998 |
A |
5985043 |
Zhou et al. |
Nov 1999 |
A |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/057587 |
Sep 1997 |
US |
Continuations (1)
|
Number |
Date |
Country |
Parent |
09/148506 |
Sep 1998 |
US |
Child |
10/051661 |
|
US |