Method for making semiconductor package
View Patent ↗A method for assembling a semiconductor package includes a rapid cooling step after post mold curing of an encapsulation material. The rapid cooling step includes blowing chilled, compressed air over the package for about two minutes. The rapid cooling step does not require any clamping pressure be simultaneously applied to the package. The rapid cooling step reduces a temperature of the encapsulation material from a curing temperature to the cooled temperature within a maximum period of less than five minutes. By using rapid cooling, as opposed to cooling the package under a clamping pressure with ambient air, package warpage due to CTE mismatches is prevented.
1. A method for assembling a Flat No-lead semiconductor package, comprising:
mounting a base surface of a semiconductor die to a support substrate;
electrically connecting die electrical connection pads on an upper surface of the die to respective external connection pads that are mounted to the support substrate;
encapsulating the semiconductor die and external connection pads with an encapsulation material to form the semiconductor package, wherein the encapsulation material and support substrate sandwich the external connection pads therebetween;
curing the encapsulation material at a curing temperature; and
rapidly cooling the encapsulation material from the curing temperature to a cooled temperature of no more than fifty degrees centigrade, the rapid cooling being at least partially assisted by a fluid flow directed over the encapsulation material to thereby reduce a temperature of the encapsulation material from a curing temperature to the cooled temperature within a maximum cooling period of less than five minutes.
2. The method of claim 1 , wherein the fluid flow is an air flow.
3. The method of claim 2 , wherein the air flow has a rate of flow of at least 1 meter per second.
4. The method of claim 2 , wherein the air flow is provided by at least one fan.
5. The method of claim 2 , wherein a temperature of the air directed over the encapsulation material is at ambient temperature.
6. The method of claim 2 , wherein a temperature of the air directed over the encapsulation material is twenty-five degrees centigrade or less.
7. The method of claim 1 , wherein the maximum cooling period is less than three minutes.
8. The method of claim 1 , wherein the curing temperature is one hundred and seventy five degrees centigrade plus or minus ten percent.
9. The method of claim 8 , wherein the curing is performed for five hours plus or minus ten percent.
10. A method for assembling a semiconductor package, comprising:
mounting a semiconductor die to a support substrate;
electrically connecting the die to the support substrate;
encapsulating the semiconductor die and at least a portion of the top surface of the support substrate with an encapsulation material to form the semiconductor package;
curing the encapsulation material at a curing temperature; and
rapidly cooling the encapsulation material from the curing temperature to a cooled temperature of no more than fifty degrees centigrade, the rapid cooling being at least partially assisted by a fluid flow directed over the encapsulation material to thereby reduce a temperature of the encapsulation material from a curing temperature to the cooled temperature within a maximum cooling period of less than five minutes.
11. The method of claim 10 , wherein the fluid flow is an air flow having a flow rate of at least 1 meter per second.
12. The method of claim 11 , wherein a temperature of the air directed over the encapsulation material is twenty-five degrees centigrade or less.
13. The method of claim 10 , wherein the maximum cooling period is less than three minutes.
14. The method of claim 10 , wherein the curing temperature is one hundred and seventy five degrees centigrade plus or minus ten percent.
15. The method of claim 14 , wherein the curing is performed for five hours plus or minus ten percent.