SHIELDED WIREBOND

• US 20100025864A1
• Filed: 07/31/2008
• Published: 02/04/2010
• Est. Priority Date: 07/31/2008
• Status: Abandoned Application

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bailey, Mark J., Maki, Andrew B., Bartley, Gerald K., Germann, Philip R., Maxson, Mark O., Becker, Darryl J., Dahlen, Paul E.
• Application Number:
  US12/183,483
• Publication Number:
  US 20100025864A1
• Time in Patent Office: Days
• US Class Current: 257/784
• CPC Class Codes: H01L 2223/6611 Wire connections
• CPC Class Codes: H01L 2223/6622 Coaxial feed-throughs in active or passive substrates
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 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 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/78 Apparatus for connecting with wire connectors
• CPC Class Codes: H01L 2224/83951 Forming additional members, e.g. for reinforcing, fillet sealant
• CPC Class Codes: H01L 2224/85801 Soldering or alloying
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 23/3121 a substrate forming part of the encapsulation
• CPC Class Codes: H01L 23/3135 Double encapsulation or coating and encapsulation
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• 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 24/73 : Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 24/85 : using a wire connector wire bonding in general B23K20/004
• 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 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/06 : Polymers polymers per se C08; polymer adhesives C09J
• CPC Class Codes: H01L 2924/30107 : Inductance
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding

Abstract

A wirebond interconnect structure, having ground pads and signal pads, to which wirebonds are electrically coupled, disposed on a component, is provided and includes a first coating to insulate at least the wirebonds and the signal pads with at least the ground pads exposed, and a second coating, surrounding the first coating, in electrical communication with the ground pads. The first coating is sufficiently thick to achieve a consistent characteristic impedance when the second coating is applied.

Claims

1. A wirebond interconnect structure, having ground pads and signal pads, to which wirebonds are electrically coupled, disposed on a component, the structure comprising:

a first coating to insulate at least the wirebonds and the signal pads with at least the ground pads exposed; and

a second coating, surrounding the first coating, in electrical communication with the ground pads, wherein the first coating is sufficiently thick to achieve a consistent characteristic impedance when the second coating is applied.

2. The structure according to claim 1, wherein the first coating comprises insulating material.

3. The structure according to claim 1, wherein the first coating comprises an insulative conformal coating.

4. The structure according to claim 1, wherein the first coating comprises a silicone-based conformal coating.

5. The structure according to claim 1, wherein the second coating comprises an electrically conductive coating.

6. The structure according to claim 5, wherein the electrically conductive coating comprises a coating with particulate fillings.

7. The structure according to claim 1, wherein the second coating comprises an electrically conductive conformal coating.

8. The structure according to claim 1, wherein the second coating comprises an electrically conductive non-conformal coating.

9. A wirebond interconnect structure comprising:

a component, on which ground pads and signal pads are disposed;

wirebonds, which are electrically coupled to the signal pads;

a first coating to insulate at least the wirebonds and the signal pads with at least the ground pads exposed; and

a second coating, surrounding the first coating, in electrical communication with the ground pads, wherein the first coating is sufficiently thick to achieve a consistent characteristic impedance when the second coating is applied.

10. A method of forming a wirebond interconnect structure, having ground pads and signal pads, to which wirebonds are electrically coupled, disposed on a component, the method comprising:

masking the ground pads;

applying a first coating to insulate at least the wirebonds and the signal pads and to have a pre-selected thickness;

unmasking the ground pads; and

applying a second coating to surround the first coating and to be in electrical communication with the ground pads, wherein the pre-selected thickness is sufficient to achieve a consistent characteristic impedance when the second coating is applied.

11. The method according to claim 10, wherein the masking of the ground pads comprises forming a mask that is reflective of positions, shapes and sizes of the ground pads with respect to the component.

12. The method according to claim 10, wherein the masking of the ground pads comprises a partial masking of the ground pads.

13. The method according to claim 10, wherein the applying of the first coating comprises regulating an output of a material of the first coating through a flow valve therefore.

14. The method according to claim 10, wherein the applying of the first coating comprises spray coating the first coating onto the wirebonds and the signal pads.

15. The method according to claim 10, wherein the applying of the first coating comprises dip coating the first coating onto the wirebonds and the signal pads.

16. The method according to claim 10, wherein the applying of the first coating comprises:

applying a first layer of the first coating to insulate the wirebonds and the signal pads; and

applying additional layers of the first coating to achieve the characteristic impedance matching.

17. The method according to claim 10, wherein the applying of the second coating comprises applying the second coating to conformally surround the first coating.

18. The method according to claim 10, wherein the applying of the second coating comprises applying the second coating to non-conformally surround the first coating.