Cavity-type semiconductor package and method of packaging same
View Patent ↗A method ( 30 ) of forming a semiconductor package ( 20 ) entails applying ( 56 ) an adhesive ( 64 ) to a portion ( 66 ) of a bonding perimeter ( 50 ) of a base ( 22 ), with a section ( 68 ) of the perimeter ( 50 ) being without the adhesive ( 64 ). A lid ( 24 ) is placed on the base ( 22 ) so that a bonding perimeter ( 62 ) of the lid ( 24 ) abuts the bonding perimeter ( 50 ) of the base ( 22 ). The lid ( 24 ) includes a cavity ( 25 ) in which dies ( 38 ) mounted to the base ( 22 ) are located. A gap ( 70 ) is formed without the adhesive ( 64 ) at the section ( 68 ) between the base ( 22 ) and the lid ( 24 ). The structure vents from the gap ( 70 ) as air inside the cavity ( 25 ) expands during heat curing ( 72 ). Following heat curing ( 72 ), another adhesive ( 80 ) is dispensed in the section ( 68 ) to close the gap ( 70 ) and seal the cavity ( 25 ).
1. A method of attaching a lid to a base to form a cavity-type semiconductor package, said lid being shaped to include a cavity, a semiconductor die being coupled to a surface of said base within an area delineated by a first bonding perimeter of said base, said lid having a second bonding perimeter, and said method comprising:
applying an electrically conductive epoxy adhesive material to a portion of at least one of said first and second bonding perimeters such that a remaining section of both of said first and second bonding perimeters is without said electrically conductive epoxy adhesive material;
placing said lid on said base so that said second bonding perimeter abuts said first bonding perimeter and a gap is produced between said base and said lid at a location where said remaining section is without said electrically conductive epoxy adhesive material;
heat curing said electrically conductive epoxy adhesive material, said heat curing occurring at a first temperature of at least one hundred seventy degrees Celsius, wherein during said heat curing operation, air inside said cavity expands in response to said first temperature and said gap allows venting of said air from said cavity; and
following said heat curing, applying a second adhesive material to said remaining section to close said gap.
2. A method as claimed in claim 1 wherein said method further comprises curing said second adhesive material applied to said remaining section at a second temperature that is less than said first temperature.
3. A method as claimed in claim 2 wherein said second temperature is room temperature.
4. A method as claimed in claim 1 further comprising curing said second adhesive material applied to said remaining section by exposing said second adhesive material to ultraviolet radiation.
5. A method as claimed in claim 1 further comprising curing said second adhesive material applied to said remaining section to hermetically seal said cavity.
6. A method as claimed in claim 1 wherein said applying said second adhesive material occurs following said placing operation.
7. A method as claimed in claim 1 further comprising applying said second adhesive material around an entire outer perimeter of said lid at a junction between said base and said lid.
8. A method as claimed in claim 1 wherein:
said applying said first adhesive material includes producing multiple remaining sections of both of said first and second bonding perimeters that are without said first adhesive material so that multiple gaps are produced following said placing operation; and
said applying said second adhesive material dispenses said second adhesive material to close each of said multiple gaps.
9. A method of attaching a lid to a base to form a cavity-type semiconductor package, said lid being shaped to include a cavity, a semiconductor die being coupled to a surface of said base within an area delineated by a first bonding perimeter of said base, said lid having a second bonding perimeter, and said method comprising:
applying a first adhesive material to a portion of at least one of said first and second bonding perimeters such that a remaining section of both of said first and second bonding perimeters is without said first adhesive material;
placing said lid on said base so that said second bonding perimeter abuts said first bonding perimeter and a gap is produced between said base and said lid at a location where said remaining section is without said first adhesive material;
heat curing said first adhesive material, said heat curing occurring at a first temperature of at least one hundred seventy degrees Celsius, wherein during said heat curing operation, air inside said cavity expands in response to said first temperature and said gap allows venting of said air from said cavity; and
following said placing and heat curing operations, applying a second adhesive material to said remaining section to close said gap.
10. A method as claimed in claim 9 further comprising curing said second adhesive material applied to said remaining section to hermetically seal said cavity, said curing said second adhesive occurring at room temperature.
11. A method as claimed in claim 10 wherein said curing said second adhesive material includes exposing said second adhesive material to ultraviolet radiation.