Electrostatic discharge protection device

• US 5,583,733 A
• Filed: 12/21/1994
• Issued: 12/10/1996
• Est. Priority Date: 12/21/1994
• Status: Expired due to Fees

• Current Assignee: Senshin Capital LLC (Intellectual Ventures LLC)
• Original Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Inventors: Cronin, David V.
• Primary Examiner(s): Gaffin, Jeffrey A.
• Assistant Examiner(s): Jackson, Stephen W.
• Application Number:
  US08/361,426
• Time in Patent Office: 720 Days
• Field of Search: 361/56, 361/91, 361/118, 361/220, 361/115, 361/119, 361/111, 439/188, 439/507
• US Class Current: 361/111
• CPC Class Codes: H01L 23/60 Protection against electrostatic charges or discharges, e.g. Faraday shields
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 13/0084 Containers and magazines for components, e.g. tube-like magazines

Abstract

An electrostatic discharge protection device is disclosed which automatically connects selected connector pins of a semiconductor chip package ("SCP") or connectors on printed circuit boards such that the connector pins are held at a common voltage until insertion of the SCP into a receptor or until insertion of a cable into the connector which overcomes an internal resilient bias of the electrostatic discharge protection device causing the common connection to be removed. Removal of the SCP from the receptor or the cable from its connector removes the force which overcomes the bias, thereby reestablishing the common electrical connection thus automatically moving the electrostatic discharge protection device between inoperative and operative positions.

Claims

1. An electrostatic discharge protection device for use with a semiconductor chip package of a type having a plurality of connector pins extending therefrom disposed in a spaced apart relationship with respect to each other for insertion into a mating receptacle, said electrostatic discharge protection device comprising

a non-conductive base having a plurality of legs extending outward therefrom where each of said plurality of legs has an aperture at a distal end passing therethrough for receiving one of the plurality of connector pins, said non-conductive base having an operative position in which an inherent bias of the non-conductive base urges an outer edge of each aperture into mechanical contact with the plurality of connector pins held within and having an inoperative position where the mechanical contact between the outer edge of each aperture and the one of the plurality of connector pins is disconnected, where insertion of said semiconductor chip package into said mating receptacle moves the non-conductive base into the inoperative position by overcoming the inherent bias and removal of the semiconductor chip package from the mating receptacle automatically returns the non-conductive base to said operative position;

conductive means disposed on said non-conductive base for electrically connecting selected ones of said plurality of connector pins when the non-conductive base is in the operative position by establishing an electrical path between each of the outer edges of the apertures contacting the selected ones of said plurality of connector pins, and for disconnecting said electrical path when the non-conductive base is in the inoperative position to provide electrical isolation between the plurality of connector pins.

2. The electrostatic discharge protection device according to claim 1 wherein said inherent bias draws the outer portion of the plurality of apertures into contact with the connector pins with sufficient force to automatically secure the base on the semiconductor chip package.

3. The electrostatic discharge protection device according to claim 1 wherein each of said plurality of apertures has an inner edge proximal to the central axis and when the non-conductive base is held flat, a first distance between opposed sets of the inner edges is approximately equal to a second distance between opposed sets of the plurality of connector pins which provides automatic centering of the electrostatic discharge protection device upon movement of the electrostatic discharge protection device into said inoperative position.

4. The electrostatic discharge protection device according to claim 1 wherein said non-conductive base has holes for receiving the plurality of connector pins with an interference fit to secure the electrostatic discharge protection device on the semiconductor chip package.

5. The electrostatic discharge protection device according to claim 1 wherein said shape of said base mimics an orientation of the plurality of connector pins.

6. The electrostatic discharge protection device according to claim 1 wherein said conductive means is fabricated from a conductive coating which is applied onto the non-conductive base.

7. The electrostatic discharge protection device according to claim 6 wherein said conductive coating is applied so as to run over said outer edge of each of said plurality of apertures to ensure electrical contact with each of said plurality of connector pins.

8. The electrostatic discharge protection device according to claim 1 wherein said conductive means is fabricated from a flex-circuit material laminated to the non-conductive base.

9. The electrostatic discharge protection device according to claim 8 wherein said flex-circuit is photo-etched to leave a prominent edge overlapping the outer edge of each of said plurality of apertures to ensure electrical contact with each of said plurality of connector pins.

10. The electrostatic discharge protection device according to claim 1 wherein said non-conductive base has an arcuate shape which draws the plurality of apertures together and said arcuate shape is formed such that a horizontal distance between opposed sets of the plurality of apertures is less than a distance between opposed sets of the plurality of connector pins thereby increasing said inherent bias.

11. The electrostatic discharge protection device according to claim 10 wherein said arcuate shape is parabolic.

12. An electrostatic discharge protection device for use with a connector of a type having a top with a sequence of connector pins extending therefrom disposed in a spaced apart relationship with respect to each other for insertion into a mating receptacle, said electrostatic discharge protection device comprising

a base adapted to be secured to said connector, said base having a plurality of apertures with cuts along either side of the plurality of apertures, the plurality of apertures corresponding to the sequence of connector pins such that the sequence of connector pins pass through the plurality of apertures and the cuts providing independent motion to each of the plurality of apertures where said independent motion allows each of the plurality of apertures to adapt to a position of the sequence of connector pins, said base having a resilient inward bias to urge an outer portion of the plurality of apertures into contact with the connector pins;

and

grounding means disposed on said base for providing electrical communication between selected of the outer portions of the plurality of apertures

where said electrostatic discharge protection device has an operative position for connecting a shunt across selected pins of the sequence of connector pins and has an inoperative position for disconnecting said shunt to provide electrical isolation between the sequence of connector pins where insertion of said connector into said mating receptacle moves the grounding means into the inoperative position by overcoming the inward bias and removal of the semiconductor chip package from the mating receptacle automatically moves the grounding means into said operative position.

13. The electrostatic discharge protection device according to claim 12 wherein said cuts comprise

at least one side cut extending from a lateral edge of each of the plurality of apertures in toward a central axis of the base;

and

a center cut extending from a periphery of said base substantially bisecting each of the plurality of apertures.

14. The electrostatic discharge protection device according to claim 12 wherein said cuts form bifurcated tabs between the aperture and the periphery of the base, said tabs having electrical contacts from said grounding means disposed thereon for contacting said plurality of connector pins and said electrical contacts are redundant for each conductor pin.

15. The electrostatic discharge protection device according to claim 12 wherein said cuts comprise at least one full cut extending from a periphery of said base in toward a central axis of the base.

16. The electrostatic discharge protection device according to claim 12 wherein said base has holes for receiving the at least one row of connector pins with an interference fit to secure the electrostatic discharge protection device on the semiconductor chip package.

17. An electrostatic discharge protection device for use with a semiconductor chip package of a type having a top surface and an opposite bottom surface and a plurality of lateral surfaces integral with said top and bottom surfaces where one or more of said lateral surfaces have extending therefrom a plurality of connector pins disposed in a spaced apart relationship with respect to each other for insertion into a mating receptacle, said electrostatic discharge protection device comprising

a base adapted to be secured below the bottom surface of said semiconductor chip package having a plurality of apertures corresponding to the plurality of connector pins such that the plurality of connector pins pass through the plurality of apertures, said base having a resilient inward bias to urge an outer portion of the plurality of apertures into contact with the connector pins;

and

grounding means disposed on said base to ground selected pins of the plurality of connector pins, said grounding means having an operative position for connecting a shunt across selected pins of the plurality of connector pins, and having an inoperative position for disconnecting said shunt allowing electrical isolation between the plurality of connector pins where insertion of said grounding means into said inoperative position by overcoming the inward bias and removal of the semiconductor chip package from the mating receptacle automatically moves the grounding means into said operative position.

18. The electrostatic discharge protection device according to claim 17 wherein said plurality of apertures each have an inner edge proximal to the central axis and when the base is held flat a distance between said inner edges of opposed sets of the plurality of apertures is approximately equal to a distance between opposed sets of the plurality of connector pins causing the electrostatic discharge protection device to automatically center itself upon movement into said inoperative position.

19. The electrostatic discharge protection device according to claim 17 wherein said resilient bias draws the outer portion of the plurality of apertures into contact with the connector pins with sufficient force to automatically secure the base on the semiconductor chip package.

20. The electrostatic discharge protection device according to claim 19 wherein said base has an arcuate shape which draws the plurality of apertures together such that a distance between opposed sets of the plurality of apertures is less than a distance between opposed sets of the plurality of connector pins thereby increasing said resilient bias.

21. The electrostatic discharge protection device according to claim 20 wherein said arcuate shape is parabolic.

22. The electrostatic discharge protection device according to claim 17 wherein said base has cuts along either side of the plurality of apertures to provide independent motion of each of the plurality of apertures where said independent motion allows each of the plurality of apertures to adapt to a position of the plurality of connector pins.

23. The electrostatic discharge protection device according to claim 22 wherein said cuts comprise at least one full cut extending from a periphery of said base in toward a central axis of the base.

24. The electrostatic discharge protection device according to claim 22 wherein said base is fabricated from a nonconductive material to alleviate unintended electrical short circuits.

25. The electrostatic discharge protection device according to claim 22 wherein said base has holes for receiving the plurality of connector pins with an interference fit to secure the electrostatic discharge protection device on the semiconductor chip package.

26. The electrostatic discharge protection device according to claim 22 wherein said cuts comprise

at least one side cut extending from a lateral edge of each of the plurality of apertures in toward a central axis of the base;

and

a center cut extending from a periphery of said base substantially bisecting each of the plurality of apertures.

27. The electrostatic discharge protection device according to claim 26 wherein said cuts form bifurcated tabs between the aperture and the periphery of the base, said tabs having electrical contacts from said grounding means disposed thereon for contacting said plurality of connector pins and said electrical contacts are redundant for each conductor pin.

28. The electrostatic discharge protection device according to claim 22 wherein said grounding means is a conductive coating.

29. The electrostatic discharge protection device according to claim 28 wherein said conductive coating is applied so as to run over an outer edge of each of said plurality of apertures to ensure electrical contact with each of said plurality of connector pins.

30. The electrostatic discharge protection device according to claim 22 wherein said grounding means is a flex-circuit laminated to the base.

31. The electrostatic discharge protection device according to claim 30 wherein said flex-circuit is photo-etched to leave a prominent edge overlapping into an inner edge of each of said plurality of apertures to ensure electrical contact with each of said plurality of connector pins.

32. An electrostatic discharge protection device for use with a semiconductor chip package of a type having a top surface and an opposite bottom surface and a plurality of lateral surfaces integral with said top and bottom surfaces where one or more of said lateral surfaces have planar electrical contacts disposed thereon and said bottom surface is for mating with a substantially planar surface, said electrostatic discharge protection device comprising

a body having a base adapted to be secured around said plurality of lateral surfaces of said semiconductor chip package where an aperture is cut therethrough over each of the planar electrical contacts, and having a tab extending out from the from the base below said bottom surface corresponding to each of the planar electrical contacts where said tab folds back into said base such that a portion of the tabs extends into the aperture, said tab having a resilient inward bias to urge the tab through the apertures into contact with the planar electrical contact;

and

grounding means disposed on said body having an operative position to shunt selected planar electrical contacts, said grounding having a ground contact on the tab which establishes an electrical path with selected ones of each of the said planar electrical contacts and having a central conductor to provide electrical communication between the ground contacts, said grounding means having an inoperative position for disconnecting the shunt allowing electrical isolation between the planar electrical contacts where attachment of the bottom surface of the semiconductor chip package to said substantially planar surface moves said grounding means into an inoperative position by overcoming the inward bias of the tab and pushing the ground contact away from the planar electrical contact, and removal of the semiconductor chip package from the substantially planar surface automatically moves the grounding means back into said operative position.