Method for controlling thermal interface gap distance

A method for assembling an electronic chip assembly, comprising the steps of:

• (a) providing a substrate having a surface with an electronic circuit chip affixed to the surface and at least one connection location on the surface;
• (b) providing a lid covering the chip and including an upper sealing member for coupling to the substrate;
• (c) applying a sealant to at least one of the upper sealing member and the at least one connection location on the surface of the substrate disposed for coupling the upper sealing member to the at least one connection location;
• (d) applying a thermal interface material over a top surface of the chip, the thermal interface material having an original thickness greater than a final gap spacing;
• (e) applying a first force thereby joining the substrate to the lid, the upper sealing member being coupled to the substrate, the lid covering the chip and contacting the thermal interface material, the thermal interface material being compressed to a final thickness, wherein the first force is within the range of 15 to 100 pounds along a joining direction;
• and
• (f) curing the sealant by heating and applying a second force being at most equal to the first force,
• wherein the final gap spacing comprises a distance between a lower surface of the lid and the top surface of the chip in the electronic chip assembly.

A method for manufacturing an electronic flip chip assembly comprising a substrate, a chip, a lid connected to said chip through a thermal interface layer having a predetermined desired thickness, said lid comprising a greater horizontal extent than the chip and having a lid portion which overhangs the chip, wherein the method comprises:

• (a) forming on said lid and said substrate complementary male and female parts of a sealing structure;
• (b) depositing on an upper surface of said chip a pliant, heat-conductive material to a first thickness greater than said predetermined desired thickness;
• (c) applying a pliant curable adhesive to one or both of said complementary male and female parts of said sealing structure;
• (d) placing said lid over said chip in contact with said pliant, heat-conducting material with said complementary male and female parts of said sealing structure aligned with each other;
• (e) applying a first force to said lid and said chip along a joining direction sufficient to compress said pliant, heat-conducting material to said predetermined desired thickness and to compress said pliant adhesive engaging said complementary male and female parts of said sealing structure wherein said first force is within the range 15 to 100 pounds;
• (f) replacing said first force with a second force also applied to said lid and said chip along a joining direction sufficient to maintain said predetermined desired thickness;
• (g) curing said curable adhesive while applying said second force;
• and
• (h) removing said second force after said adhesive has cured at least sufficiently to retain said lid on said chip with said pliant, heat-conductive material in substantially said predetermined desired thickness when said second force is removed.