Radiation shielding of integrated circuits and multi-chip modules in ceramic and metal packages

• US 5,635,754 A
• Filed: 01/13/1995
• Issued: 06/03/1997
• Est. Priority Date: 04/01/1994
• Status: Expired due to Term

• Current Assignee: Maxwell Technologies Incorporated (Tesla Inc.)
• Original Assignee: Space Electronics, Inc. (Tesla Inc.)
• Inventors: Czajkowski, David R., Strobel, David J.
• Primary Examiner(s): Crane, Sara W.
• Assistant Examiner(s): OSTROWSKI, DAVID M
• Application Number:
  US08/372,289
• Time in Patent Office: 872 Days
• Field of Search: 257/659, 257/660, 257/698, 257/699, 257/704, 257/708, 257/710, 361/816, 361/818, 361/820
• US Class Current: 257/659
• CPC Class Codes: H01L 2224/05553 being rectangular
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/4823 connecting the wire to a pin of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 23/055 the leads having a passage through the base H01L23/057 takes precedence
• CPC Class Codes: H01L 23/057 the leads being parallel to the base
• CPC Class Codes: H01L 23/18 Fillings characterised by the material, its physical or chemical properties, or its arrangement within the complete device
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 25/0655 the devices being arranged next to each other
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01039 Yttrium [Y]
• CPC Class Codes: H01L 2924/01057 : Lanthanum [La]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/10161 : with a rectangular active surface
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15153 : the die mounting substrate comprising a recess for hosting the device
• CPC Class Codes: H01L 2924/15165 : Monolayer substrate
• CPC Class Codes: H01L 2924/15312 : being a pin array, e.g. PGA
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/1616 : Cavity shape
• CPC Class Codes: H01L 2924/1617 : Cavity coating
• CPC Class Codes: H01L 2924/16195 : Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding

Abstract

The radiation shielded and packaged integrated circuit semiconductor device includes a lid secured to a base to enclose the integrated circuit die within, wherein the lid and the base are each constructed from a high-Z material to prevent radiation from penetrating therethrough. Another embodiment includes a die attach slug constructed from a high-Z material disposed between the integrated circuit die and a base, in combination with a high-Z material lid to substantially block incident radiation.

Claims

1. A radiation shielded integrated circuit device to protect an integrated circuit die having an associated total dose tolerance from damage caused by naturally occurring ionizing radiation in outer space, comprising:

a generally flat shielding base member constructed from a high Z material to reduce substantially the amount of ionizing radiation including electron radiation passing therethrough, wherein the integrated circuit die is secured directly to an inner top surface of said flat base member;

upstanding shielding sidewalls extending from the peripheral edges of said flat base member and being constructed from a high Z material to reduce substantially the amount of ionizing radiation including electron radiation passing therethrough;

means for defining feedthrough openings in said shielding sidewalls;

a plurality of leads extending through said openings in said shielding sidewalls to facilitate an electrical connection with the die;

wherein the die is received on said top surface in a centrally disposed position thereon and substantially spaced apart from said sidewalls;

a plurality of wire bonds connected directly between said leads and the die for facilitating the electrical connection therebetween; and

a shielding lid member constructed from said high Z material to reduce substantially the amount of ionizing radiation including electron radiation passing therethrough, said lid member being secured to said sidewalls to enclose substantially the integrated circuit die for reducing the ionizing radiation received at the integrated circuit die to a level less than the total dose tolerance.

2. A radiation shielded integrated circuit device according to claim 1, wherein said base member is circular and has an associated circumference, said lid member includes a circular top portion having another circumference and a wall extending down from the perimeter of said top portion, and said base member circumference being slightly smaller than said top portion for enabling said base member to be received within a circular opening formed by said wall to form a can type metal package.

3. A radiation shielded integrated circuit device according to claim 1, further including a pair of upstanding interior shielding sidewall members secured to said inner top surface of said base member, each one of said interior sidewall members being disposed between a respective one of said sidewalls and the die and extending upwardly toward said lid member to form a barrier to help surround the integrated circuit die, said interior sidewall members being constructed from said Z number material.

4. A radiation shielded integrated circuit device according to claim 3, wherein said wire bonds electrically connecting said plurality of leads to the integrated circuit die are insulated.

5. A radiation shielded integrated circuit device according to claim 1, wherein said base member includes a rectangular bottom portion and four wall portions extending upwardly from the perimeter of said bottom portion at about right angles thereto, said base member having at least two insulated feed-through portions, each one of said insulated feed-through portions being disposed on opposite sides of said base member to receive a package lead therethrough, and said lid member being substantially similar in size and shape to said bottom portion for enabling said lid member to engage said wall portions to form a dual-in-line metal package.

6. A radiation shielded integrated circuit device according to claim 1, wherein said high Z material is a copper-tungsten alloy.

7. A radiation shielded integrated circuit device according to claim 1, wherein said high Z material is tantalum.

25. A radiation shielded integrated circuit device according to claim 1, wherein said shielding base member, sidewalls and lid member are also constructed with a low Z material in combination with said high Z material to form a shielding material, said shielding material consisting essentially of:

a high Z substance for ionizing radiation shielding selected from the group consisting of tungsten, tantalum and lead;

a low Z substance for ionizing radiation shielding to act as an extender to decrease the overall density of the shielding material and selected from the group consisting of copper, aluminum and silicon.

26. A formulation for a shield material according to claim 25, wherein the shield material includes about 85% high Z substance and about 15% low Z substance.

27. A formulation for a shield material according to claim 25, wherein the shield material includes about 80% high Z substance and about 20% low Z substance.

28. A formulation for a shield material according to claim 25, wherein the shield material includes about 90% high Z substance and about 10% low Z substance.

8. A method of making a radiation shielded integrated circuit device to protect an integrated circuit die having an associated total dose tolerance from damage caused by naturally occurring ionizing radiation in outer space, comprising:

forming a generally flat shielding base member with a high Z material to reduce substantially the amount of ionizing radiation including electron radiation passing therethrough;

securing the integrated circuit die directly to an inner top surface of said flat base member;

forming upstanding shielding sidewalls extending from the peripheral edges of said flat base member and being constructed from a high Z material to reduce substantially the amount of ionizing radiation including electron radiation passing therethrough;

defining feedthrough openings in said shielding sidewalls;

extending a plurality of leads through said openings in said shielding sidewalls to facilitate an electrical connection with the die;

wherein the die is received on said top surface in a centrally disposed position thereon and substantially spaced apart from said side walls;

connecting directly a plurality of wire bonds between said leads and the die for facilitating the electrical connection therebetween;

forming a shielding lid member with said high Z material to reduce substantially the amount of ionizing radiation including electron radiation passing therethrough; and

securing said shielding lid member to said shielding sidewalls to enclose substantially said integrated circuit die for reducing the total dose radiation of ionizing radiation received at the integrated circuit die to a level less than said total dose tolerance.

9. A method of making a radiation shielded integrated circuit device according to claim 8, wherein said securing said shielding lid member to said shielding sidewalls includes using a solder seal technique.

10. A method of making a radiation shielded integrated circuit device according to claim 8, wherein said securing said shielding lid member to said shielding sidewalls includes using an epoxy technique.

11. A method of making a radiation shielded integrated circuit device according to claim 8, wherein said securing said shielding lid member to said shielding sidewalls includes using a resistance welding technique.

12. A radiation shielded integrated circuit device to protect an integrated circuit die having an associated total dose tolerance from damage caused by naturally occurring ionization radiation in outer space, comprising:

a generally flat non-shielding base member;

a shielding die attach slug member secured to an inner flat top surface of said base member for protecting the integrated circuit die attached to said die attach slug member, wherein said shielding die attach slug member is larger than the integrated circuit die and is constructed from a high Z material to substantially reduce the amount of ionizing radiation including electron radiation passing therethrough to reach the integrated circuit die;

upstanding non-shielding sidewalls extending from the peripheral edges of said flat non-shielding base member;

means for defining feedthrough openings in said non-shielding sidewalls;

a plurality of leads extending through said openings in said non-shielding sidewalls to facilitate an electrical connection with the die;

wherein the shielding die attach slug member is received on said top surface in a centrally disposed position thereon and substantially spaced apart from said sidewalls;

a plurality of wire bonds connected directly between said leads and the die for facilitating the electrical connection therebetween; and

a shielding lid member constructed from said high Z material to reduce substantially the amount of ionizing radiation including electron radiation passing therethrough, said shielding lid member being secured to said sidewalls to enclose partially the integrated circuit die between said shielding lid member and said shielding die attach slug member for reducing the ionizing radiation received at the integrated circuit die to a level less than the total dose tolerance.

13. A radiation shielded integrated circuit device according to claim 12, wherein said base member is constructed from a ceramic material.

14. A radiation shielded integrated circuit device according to claim 12, wherein said base member is constructed from a metallic material.

15. A radiation shielded integrated circuit device according to claim 12, wherein said shielding die attach slug member includes a plurality of shielding sidewall members extending upwardly toward said shielding lid member to partially surround the integrated circuit die, said shielding sidewall members being constructed from said high Z material.

16. A radiation shielded integrated circuit device according to claim 14, wherein said wire bonds electrically connecting said plurality of package leads to the integrated circuit die are insulated.

17. A radiation shielded integrated circuit device according to claim 15, further including a plurality of integrated circuit dies, each one of said integrated circuit dies being secured to a corresponding die attach slug member.

18. A method of making a radiation shielded integrated circuit device to protect an integrated circuit die having an associated total dose tolerance from damage caused by naturally occurring ionizing radiation in outer space, comprising:

forming a non-shielding base member

securing a shielding die attach slug member to an inner flat top surface of said base member;

securing the integrated circuit die to said die attach slug member, wherein said die attach slug member is larger than said integrated circuit die and is constructed from a high Z material to reduce substantially the amount of ionizing radiation including electron radiation passing therethrough to reach said integrated circuit die;

forming upstanding non-shielding sidewalls extending upwardly from the peripheral edges of said flat non-shielding base member;

defining feedthrough openings in said non-shielding sidewalls;

extending a plurality of leads through said openings in said non-shielding sidewalls to facilitate an electrical connection with the die;

wherein the shielding die attach slug member is received on said top surface in a centrally disposed position thereon and substantially spaced apart from said sidewalls;

connecting a plurality of wire bonds directly between said leads and the die for facilitating the electrical connection therebetween; and

forming a shielding lid member from said high Z material to reduce substantially the amount of ionizing radiation including electron radiation passing therethrough; and

securing said shielding lid member to said non-shielding sidewalls to enclose partially said integrated circuit die between said shielding lid member and said shielding die attach slug member for reducing the ionizing radiation received at said integrated circuit die to a level less than said total dose tolerance.

19. A method of forming a radiation shielded integrated circuit according to claim 18, further including forming a plurality of sidewall members from said Z number material on said die attach slug member which extend upwardly toward the lid member to partially surround said integrated circuit die.

20. A radiation shielded integrated circuit device to protect an integrated circuit die having an associated total dose tolerance from damage caused by naturally occurring ionizing radiation in outer space, comprising:

a flat non-shielding base member, wherein the integrated circuit die is secured directly to an inner top surface of said flat base member;

a bottom shield member secured to an outer surface of said base member to protect the integrated circuit die, wherein said bottom shield member is larger than the integrated circuit die and is constructed from a high Z material to reduce substantially the amount of ionizing radiation including electron radiation passing therethrough to reach the integrated circuit die;

upstanding non-shielding sidewalls extending from the peripheral edges of said flat non-shielding base member;

means for defining feedthrough openings in said non-shielding sidewalls;

a plurality of leads extending through said openings in said non-shielding sidewalls to facilitate an electrical connection with the die;

wherein the die is secured on said top surface in a centrally disposed position thereon and substantially spaced apart from said sidewalls;

a plurality of wire bonds connected directly between said leads and the die for facilitating the electrical connection therebetween; and

a shielding lid member constructed from said high Z material to substantially reduce the amount of ionizing radiation including electron radiation passing therethrough, said shielding lid member being secured to said non-shielding sidewalls to enclose partially the integrated circuit die between said shielding lid member and said bottom shield member for reducing the ionizing radiation received at the integrated circuit die to a level less than the total dose tolerance.

21. A radiation shielded integrated circuit device according to claim 20, wherein said non-shielding base member is constructed from a ceramic material.

22. A radiation shielded integrated circuit device according to claim 20, further including a plurality of sidewall members constructed from said high Z material and secured to said flat inner top surface of said base member to partially enclose the integrated circuit die.

23. A radiation shielded integrated circuit device according to claim 22, wherein said wire bonds electrically connecting said plurality of package leads to the integrated circuit die are insulated.

24. A method of making a radiation shielded integrated circuit device to protect an integrated circuit die having an associated total dose tolerance from damage caused by naturally occurring ionizing radiation in outer space, comprising:

forming a flat non-shielding base member;

securing a bottom shield member to an outer surface of said base member;

securing the integrated circuit die to an inner surface of said base member, wherein said bottom shield member is larger than said integrated circuit die and is constructed from a high Z material to reduce substantially the amount of ionizing radiation including electron radiation which can pass therethrough to reach said integrated circuit die;

forming upstanding non-shielding sidewalls extending from the peripheral edges of said flat non-shielding base member;

defining feedthrough openings in said non-shielding sidewalls;

extending a plurality of leads through said openings in said non-shielding sidewalls to facilitate an electrical connection with the die;

wherein the die is secured on said top surface in a centrally disposed position thereon and substantially spaced apart from said sidewalls;

connecting a plurality of wire bonds directly between said leads and the die for facilitating the electrical connection therebetween; and

forming a shielding lid member from said high Z material to reduce substantially the amount of ionizing radiation including electron radiation passing therethrough; and

securing said shielding lid member to said non-shielding sidewalls to enclose partially said integrated circuit die between said shielding lid member and said bottom shield member for reducing the ionizing radiation received at the integrated circuit die to a level less than said total dose tolerance.