An embodiment of a die assembly includes a flange, lip walls, and leads for electrical contact with one or more die mounted on the flange. The flange has first and second opposed flange surfaces and flange sidewalls extending between the surfaces. The lip walls have first and second opposed lip surfaces and lip sidewalls extending between the first and second lip surfaces. The lip sidewalls are positioned adjacent to the flange sidewalls. The leads, which have inboard end portions and outboard end portions, are configured to preserve a seating plane. The seating plane is spaced apart from a plane of the second flange surface. The inboard end portions of the leads are embedded in the lip walls, and extend from the seating plane upward through the lip walls toward the first lip surfaces. The outboard end portions are aligned substantially within the seating plane.
1. A die assembly comprising:
a flange having a first flange surface, a second flange surface opposed to the first flange surface, and flange sidewalls extending between the first flange surface and the second flange surface;
lip walls having first lip surfaces, second lip surfaces opposed to the first lip surfaces, and lip sidewalls extending between the first lip surfaces and the second lip surfaces, wherein the lip sidewalls are positioned adjacent to the flange sidewalls;
at least one die mounted over the first flange surface; and
leads for electrical contact with the at least one die, wherein the leads have inboard end portions and outboard end portions, and the leads are configured to preserve a seating plane, the seating plane spaced apart from a plane of the second flange surface, wherein the inboard end portions of the leads are embedded in the lip walls, and the inboard end portions extend from the seating plane upward through the lip walls toward the first lip surfaces, and the outboard end portions are aligned substantially within the seating plane.
2. The die assembly of claim 1 , wherein the first lip surfaces are raised with respect to the first flange surface.
3. The die assembly of claim 2 , wherein the lip walls are formed from a material selected from a group consisting of a ceramic material and a polymeric material.
4. The die assembly of claim 1 , wherein the lip walls are formed from a nonconductive material.
5. The die assembly of claim 1 , wherein the leads are isolated electrically from the lip walls by a coating or intermediate layer of a nonconductive material.
6. The die assembly of claim 1 , wherein the flange includes a platform on a perimeter of the flange and having a first platform surface, and the second lip surfaces are positioned adjacent to the first platform surface.
7. The die assembly of claim 1 , further including one or more pedestals on the first flange surface, wherein the at least one die are mounted on the one or more pedestals.
8. The die assembly of claim 1 , wherein the inboard end portions are exposed on the first lip surface for attachment of connecting leads to the at least one die.
9. The die assembly of claim 1 , wherein the lip walls are configured to impart stiffness to the flange, the stiffness sufficient to at least partially counteract thermally-induced stresses generated from coefficient of thermal expansion differentials between the flange and the at least one die during an elevated temperature die attachment process.
10. The die assembly of claim 1 , wherein a thickness of the flange between the first and second flange surfaces is about 65 mils or greater.
11. The die assembly of claim 10 , wherein the thickness of the flange is in a range of about 65 to 100 mils.
12. A die assembly comprising:
a flange having a first flange surface, a second flange surface opposed to the first flange surface, and flange sidewalls extending between the first flange surface and the second flange surface, wherein the first flange surface is adapted to receive at least one die;
a lip extending from the first flange surface, the lip configured to impart stiffness to the flange, the stiffness sufficient to at least partially counteract thermally-induced stresses generated from coefficient of thermal expansion differentials between the flange and the at least one die to be mounted thereon in an elevated temperature die attachment process;
the at least one die mounted over the first flange surface; and
leads for electrical contact with the at least one die, the leads configured to preserve a seating plane, the seating plane spaced from a plane of the second flange surface, wherein the leads are embedded in an organic composition and the leads extend from raised inboard end portions nearest the at least one die to lower outboard end portions aligned substantially within the seating plane.
13. The die assembly of claim 12 , wherein the lip has a first lip surface, a second lip surface opposed to the first lip surface, and a lip sidewall extending between the first and second lip surfaces, and wherein the lip is formed from the organic composition, the lip sidewall is positioned adjacent to a flange sidewall, and the leads are embedded in the organic composition of the lip.
14. The die assembly of claim 13 , wherein the flange includes a platform on a perimeter of the flange and having a first platform surface, and the second lip surface is positioned adjacent to the first platform surface.
15. The die assembly of claim 13 , wherein the inboard end portions are exposed on the first lip surface for attachment of connecting leads to the at least one die.
16. The die assembly of claim 12 , further including one or more pedestals on the first flange surface, wherein the at least one die are mounted on the one or more pedestals.
17. A die assembly comprising:
a flange having a first flange surface, a second flange surface opposed to the first flange surface, and flange sidewalls extending between the first flange surface and the second flange surface, wherein the first flange surface is adapted to receive at least one die;
a lip extending from the first flange surface and having an upper surface and a lip wall, the lip configured to impart stiffness to the flange, the stiffness sufficient to at least partially counteract thermally-induced stresses generated from coefficient of thermal expansion differentials between the flange and the at least one die to be mounted thereon in an elevated temperature die attachment process; and
leads having inboard end portions embedded along a length of the lip wall and extending to the upper surface of the lip to permit attachment of connections to die on the flange.
18. The die assembly of claim 17 , wherein the flange has thickness between the first and second flange surfaces in a range from about 65 to about 100 mils.
19. The die assembly of claim 17 , wherein the lip extends along a flange sidewall and the lip extends upward above the first flange surface.
20. The die assembly of claim 17 , wherein the flange comprises a platform, and the lip extends along a flange sidewall and rests on the platform.