Claims
- 1. A method of making an electronic package assembly, said method comprising:
- providing an organic substrate including a surface thereon having a plurality of electrical conductors positioned on said surface;
- positioning an electronic package having an elongated, electrically insulative housing having a lower surface and an upper surface and further including first and second opposing sides and first and second pluralities of electrically conductive leads projecting from said first and second opposing sides, respectively, such that said lower surface of said housing is located within 0.003 inch above said surface of said substrate and said conductive leads are electrically connected to respective ones of said electrical conductors on said surface of said substrate;
- substantially covering each of said conductive leads and at least a portion of a respective electrical conductor with a quantity of solder, said solder providing an electrical connection between said lead and respective conductor; and
- substantially covering said solder with encapsulant material and further positioning said encapsulant material against said first and second opposing sides of said housing in an abutting manner, said encapsulant material substantially preventing electrical disconnection between said projecting conductive leads and said solder during operation of said electronic package assembly, said disconnection caused by stresses occurring due to differences in the coefficients of thermal expansion of said organic substrate, solder and conductive leads during said operation, said encapsulant material not being located on said upper surface of said insulative housing.
- 2. The method according to claim 1 wherein said
- solder is applied using a screening operation.
- 3. The method according to claim 2 wherein said solder is applied in paste form and thereafter heated such that said solder will reflow to thereby substantially cover respective pairs of one of said conductive leads and a respective one of said electrical conductors.
- 4. The method according to claim 1 wherein said organic substrate is heated to a predetermined temperature prior to said substantially covering of said solder with said encapsulant material.
- 5. The method according to claim 4 wherein said heating is accomplished by placing said organic substrate in a hot air oven for a pre-established time period.
- 6. The method according to claim 1 wherein said encapsulant material is applied in substantially liquid form and thereafter heated to a pre-established temperature for a predetermined time period sufficient to cure said encapsulant material.
- 7. The method according to claim 6 wherein said encapsulant material is heated to approximately the glass transition temperature of said organic substrate for said predetermined time period.
- 8. The method according to claim 7 wherein said pre-established temperature is within the range of from about 110 degrees Celsius to about 140 degrees Celsius.
- 9. The method according to claim 8 wherein said predetermined time period is from about three to about four hours.
Parent Case Info
This is a divisional of application Ser. No. 07/805,435, filed Dec. 11, 1991, now abandoned.
US Referenced Citations (7)
Foreign Referenced Citations (6)
Number |
Date |
Country |
60-46095 |
Mar 1985 |
JPX |
62-45138 |
Feb 1987 |
JPX |
63-143851 |
Jun 1988 |
JPX |
1-72590 |
Mar 1989 |
JPX |
0139465 |
Oct 1990 |
JPX |
0382095 |
Apr 1991 |
JPX |
Non-Patent Literature Citations (3)
Entry |
IBM Tech. Discl. Bulletin, "Encapsulated Solder Joint for Chip Mounting" vol. 32, No. 10B, p. 480 Mar. 1990. |
IBM Technical Disclosure Bulletin vol. 33, No. 10B, Mar. 1991, pp. 205-207, "Encapsulation Schemes For C4-Bonded Tab Packages", by Ameen et al. |
"The Effects Of Thermal Cycle Stress On Potted SMT Circuit Card Assemblies", by R. M. Berg (date and journal unknown). |
Divisions (1)
|
Number |
Date |
Country |
Parent |
805435 |
Dec 1991 |
|