US 5,293,511 AGranted

Package for a semiconductor device

AssigneeTexas Instruments Incorporated

InventorsFrank Poradish, John T. McKinley

Life of this patent

Estimating the term…

Loading patent…

Abstract

A package (44) for a semiconductor device (10) includes a ceramic base (46, 146) with a mounting surface (50, 150) for supporting the device (10) and a light-transmissive cover (42, 142). A refractory seal ring (70) is fused to the base (46, 146) and to conductive paths (22) thereon. The upper surface (72) of the seal ring (70) is rendered optically flat with a selected angular relationship to the mounting surface (50). The upper and lower faces (76 & 78) of the cover (42, 142) are rendered optically flat with a selected angular relationship to each other, so that with an outer portion of the lower face (78) resting on the upper surface (72) of the seal ring (70), the faces (76, 78) have a selected angular relationship with the mounting surface (50, 150). The package (44) is expedient where the device (10) includes DMD's (30) having deflectable, light-reflective beams (32). The lower face (78) of the cover (42) includes an annular light-reflective coating (60, 160) surrounding a window (80) overlying the device (10). In some embodiments, the reflective coating (60) is deposited on the walls (56, 58) of a groove (54) formed in the lower face (78) of the cover (42). Facilities (90, 72/78 or 100) seal the cover (42, 142) to the seal ring (70). The reflective coating (60, 160) prevents any unmodulated light which is incident on the beams (32) from entering an optical system associated with the DMD-containing device (10). The sealing facilities (90, 72/78 or 100) include adhesives (90), which may contain microspheres, soft metals (90), glass frits (90), fusion bonding of the cover (42) to the seal ring (70), and solder preforms (100).

Claims79

Dependent claims

A package for a semiconductor device, the device being of the type which includes a light-reflecting beam movable between one position, in which light incident on the beam is and one or more other positions, in which the incident light is modulated, the package comprising:

a ceramic base having a mounting surface for supporting the device;
a first metallic pattern on the base, the first pattern including first metallic paths extending from the periphery of the base to the periphery of the mounting surface for electrical connection to the mounted device;
a generally torroidal and planar seal ring constituted of an electrically insulative, refractory material, the seal ring overlying the base and the first metallic paths between the peripheries of the base and the mounting surface, having its lower surface fused to the underlying base and first metallic paths and having an opposed upper surface ground and polished so as to be optically flat with a selected angular relationship relative to the mounting surface;
a light-transmissive glass cover overlying the device, which cover is generally congruent with the outer periphery of the seal ring, upper and lower faces of the cover being ground and polished to optical flatness and having a selected angular relationship to each other so that, with the outer portion of the lower face of the cover resting on the seal ring, the upper and lower faces have a selected angular relationship relative to the mounting surface, the lower face of the cover having formed therein an annular groove which generally overlies the inner periphery of the seal ring and the periphery of the mounting surface cavity, the groove being generally triangular in cross-section and having an outer wall which is generally perpendicular to the faces of the cover and an inner wall which slopes away from the outer wall toward the lower face of the cover;
a light-reflective coating on the walls of the groove;
and
means for sealing the outer portion of the lower face of the cover to the seal ring.

4 more elements

A package for a semiconductor device, the device being of the type which includes a light-reflecting beam movable between one position, in which light incident on the beam is modulated, and one or more other positions, in which the incident light is not modulated, the package comprising:

a ceramic base having a mounting surface for supporting the device;
a first metallic pattern on the base, the first pattern including first metallic paths extending from near the periphery of the base to near the periphery of the mounting surface for electrical connection to the mounted device;
a generally torroidal and planar seal ring constituted of an electrically insulative, refractory material, the seal ring overlying the base and the first metallic paths between the peripheries of the base and the mounting surface, having its lower surface fused to the underlying base and first metallic paths and having an opposed upper surface ground and polished so as to be optically flat with a selected angular relationship relative to the mounting surface;
a light-transmissive glass cover overlying the device, which cover is generally congruent with the outer periphery of the seal ring, upper and lower faces of the cover being ground and polished to optical flatness and having a selected angular relationship to each other so that, with the outer portion of the lower face of the cover resting on the seal ring, the upper and lower faces have a selected angular relationship relative to the mounting surface;
a generally annular light-reflective coating on the lower face of the cover, the coating defining a central uncoated window aligned with the device;
and
means for sealing the outer portion of the lower face of the cover to the seal ring.

4 more elements

Dependencies are inferred from the claim text.