Diode housing

• US 20010022390A1
• Filed: 12/29/2000
• Published: 09/20/2001
• Est. Priority Date: 06/30/1998
• Status: Active Grant

• Current Assignee: OSRAM GmbH (Ams-Osram AG)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Brunner, Herbert, Waitl, Gunther
• Granted Patent: US 6,624,491 B2
• Time in Patent Office: Days
• US Class Current: 257/666
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01058 Cerium [Ce]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 31/0203 Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

A housing accommodating a semiconductor chip is set out. The housing and chip may be used for sending and/or receiving radiation. Popular applications of the housing may be in light emitting diodes. The housing includes a conductor strip that is punched into two electrically isolated portions. The housing further includes a cavity extending inwards from the top of the housing. The conductor portions include respective areas that are exposed at the bottom of the cavity. The semiconductor chip is bonded to one of the exposed areas and a wire bonds the chip to the second exposed area. The conductor portions also terminate in exposed electrodes, which allow for electrical connection of the chip with external devices. A window is formed in the cavity and the walls of the housing that form the cavity may be made of a reflective material. The electrodes remain unexposed to the window but for any residual areas about the chip and bonding wire within the first and second exposed areas. By minimizing the area of the conductor exposed to the window, delamination brought about by the different thermal expansions of the window and conductor are minimized and/or eliminated. Likewise, with a reflective housing covering the base of the cavity that accommodates the window, internal radiation reflection is increased over that which was achieved with an exposed conductor.

Claims

1. An apparatus for sending or receiving radiation, comprising:

a housing having a top portion and a base, said top portion including walls defining an opening with an open top and a closed bottom;

a conductor accommodated within said housing, said conductor having two electrically isolated portions, a first portion having a first end terminating in an electrode external to said housing and a second end having a first open area exposed along said closed bottom such that said first portion is substantially surrounded by said housing but for said open area, and a second portion having a third end terminating in an electrode external to said housing and a fourth end having a second open area exposed along said closed bottom such that said second portion is substantially surrounded by said housing but for said second open area;

a semiconductor chip bonded to said first open area such that said semiconductor chip is positioned within said opening and said first open area is limited in area by said housing to substantially only accommodating said semiconductor chip;

a wire having a first end bonded to said semiconductor chip and a second end bonded to said second open area such that said wire is positioned within said opening and said second open area is limited by said housing to substantially only accommodate said wire bond; and

a window formed within said opening such that a top of said window is coplanar with a top of said housing.

2. The apparatus according to

claim 1

, wherein said first and second open area is the only part of said first and second conductor portions that is exposed within said cavity.

3. The apparatus according to

claim 1

, wherein said first and second conductor portions are coplanar.

4. The apparatus according to

claim 1

, wherein said first and second conductor portions are in a first plane and said first and second open area are in a second plane.

5. The apparatus according to

claim 1

, wherein said housing is made of a reflective material wherein at least said closed bottom is reflective of said radiation.

6. The apparatus according to

claim 5

, wherein said reflective material includes a diffuse reflective degree of at least 80%.

7. The apparatus according to

claim 1

, wherein said electrodes wrap around a portion of said base.

8. An apparatus for sending and receiving radiation, comprising:

a housing having a top portion and a base, said top portion including walls defining an opening with an open top and a closed bottom;

a conductor accommodated within said housing, said conductor having two electrically isolated portions, a first portion having a first end terminating in an electrode external to said housing and a second end having a first open area exposed along said closed bottom such that said first portion is substantially surrounded by said housing but for said open area, and a second portion having a third end terminating in an electrode external to said housing and a fourth end having a second open area exposed along said closed bottom such that said second portion is substantially surrounded by said housing but for said second open area;

a semiconductor chip bonded to said first open area such that said semiconductor chip is positioned within said opening and said first open area is limited in area by said housing to substantially only accommodating said semiconductor chip;

a wire having a first end bonded to said semiconductor chip and a second end bonded to said second open area such that said wire is positioned within said opening and said second open area is limited by said housing to substantially only accommodate said wire bond; and

a window formed within said opening such that a top of said window is coplanar with a top of said housing.

9. The apparatus according to

claim 8

, wherein said first and second open area is the only part of said first and second conductor portions that is exposed within said cavity.

10. The apparatus according to

claim 8

, wherein said first and second conductor portions are coplanar.

11. The apparatus according to

claim 8

, wherein said first and second conductor portions are in a first plane and said first and second open area are in a second plane.

12. The apparatus according to

claim 8

, wherein said housing is made of a reflective material wherein at least said closed bottom is reflective of said radiation.

13. The apparatus according to

claim 12

, wherein said reflective material includes a diffuse reflective degree of at least 80%.

14. The apparatus according to

claim 8

, wherein said electrodes wrap around a portion of said base.

15. A method of forming a housing for a semiconductor chip, said method comprising the steps of:

preparing a lead frame having multiple portions, a first portion having a first open area and said second portion having a second open area;

bonding a semiconductor to said first open area;

bonding a first end of a wire to said semiconductor and a second end of said wire to said second open area;

injection molding a housing about said first and second portions such that said first and second open areas are exposed in an opening and the rest of the first and second portions are covered by said housing; and

forming a transparent window in said opening.

16. The method according to

claim 15

, wherein said first and second open area is the only part of said first and second portions that is exposed within said opening;

and a bottom of said opening is reflective.

17. The method according to

claim 16

, wherein the step of spraying a housing further comprises the step of maintaining said first portion and first opening and second portion and second opening coplanar within said housing.

18. The method according to

claim 16

, wherein the step of injection molding a housing further comprises the step of maintaining said first portion and second portion in a first planar within said housing and forming said first open area and second open area in a second plane.

19. The method according to

claim 15

, further including the step of coating said opening with a reflective material.

20. The method according to

claim 19

, further including the step of wrapping ends of said lead frame about a base of said housing such that said ends form external conductors;

and wherein said reflective material has a diffuse reflective degree of at least 80%.