Electronic devices and a sheet strip for packaging bonding wire connections of electronic devices and method for producing them

• US 20020041017A1
• Filed: 10/04/2001
• Published: 04/11/2002
• Est. Priority Date: 10/04/2000
• Status: Active Grant

• Current Assignee: Polaris Innovations Limited (Wi-LAN Inc.)
• Original Assignee: Infineon Technologies AG
• Inventors: Reiss, Martin, Hauser, Christian, Winderl, Johann
• Granted Patent: US 6,525,416 B2
• Time in Patent Office: Days
• US Class Current: 257/678
• CPC Class Codes: B29C 33/06 using radiation , e.g. electro-magnetic waves, induction heating
• 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 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/4824 Connecting between the body and an opposite side of the item with respect to the body
• CPC Class Codes: H01L 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• CPC Class Codes: H01L 2224/73215 Layer and wire connectors
• CPC Class Codes: H01L 2224/85399 Material
• CPC Class Codes: H01L 23/057 the leads being parallel to the base
• CPC Class Codes: H01L 23/08 the material being an electrical insulator, e.g. glass
• CPC Class Codes: H01L 23/3121 a substrate forming part of the encapsulation
• CPC Class Codes: H01L 24/48 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 2924/01068 Erbium [Er]
• CPC Class Codes: H01L 2924/01077 Iridium [Ir]
• CPC Class Codes: H01L 2924/12042 LASER
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/207 : Diameter ranges
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding

Abstract

An electronic device is described that has a sheet strip for packaging bonding wire connections of the electronic device and a method for producing it. To that end, the sheet strip, has at least two preformed, opposite edge regions which cover the edge regions of the bonding channel in an overlapping manner. Furthermore, the sheet strip has a preformed central region situated between the edge regions, which central region has a bulge and thickened portion and has two convexly curved contour lines in cross section.

Claims

1. A sheet strip for covering bonding wire connections in a bonding channel of an electronic device, comprising:

at least two preformed, mutually opposite edge regions covering edge regions of the bonding channel in an overlapping manner; and

a preformed central region extending between said opposite edge regions and having a bulge and a thickened portion, said central region further having two convexly curved contour lines in cross section.

2. An electronic device, comprising:

a chip having an active surface and contact areas;

a laminate disposed on said active area of said chip and having a bonding channel with edge regions formed therein, said laminate further having contact connection areas, conductor tracks and soldering contact areas and surrounds said bonding channel, said contact areas of said chip disposed along said bonding channel;

bonding wires connecting said contact areas of said chip to said contact connection areas of said laminate; and

a flowable sheet formed of a potting compound surrounding said bonding wires in said bonding channel, said flowable sheet overlapping said edge regions of said bonding channel, said flowable sheet selected from the group consisting of a flowable sheet strip and flowable sheet patches.

3. The device according to claim 2, wherein said flowable sheet strip is a composite strip including:

a base sheet strip having at least two preformed, mutually opposite edge regions covering said edge regions of said bonding channel in an overlapping manner, and a preformed central region extending between said opposite edge regions and having a bulge and a thickened portion, said central region further having two convexly curved contour lines in cross-section; and

a covering strip of uniform thickness disposed on said base sheet strip.

4. The device according to claim 3, wherein said covering strip is formed of a shrink material and has edge regions adhesively fixed on said edge regions of said bonding channel.

5. The device according to claim 3, wherein said thickened portion in said central region of said base sheet strip is matched to a volume of said bonding channel.

6. The device according to claim 3, wherein said opposite edge regions of said base sheet strip overlapping said edge regions of said bonding channel are connected gas-tightly to said edge regions of said bonding channel.

7. The device according to claim 2, wherein a flowability of said flowable sheet strip commences at a threshold temperature.

8. The device according to claim 3, wherein a ratio between a maximum thickness of said central region of said base sheet strip to a thickness of said opposite edge regions of said base sheet strip is 3:

1.

9. The device according to claim 3, wherein a ratio between a maximum thickness of said a central region of said base sheet strip to a thickness of said opposite edge regions of said base sheet strip is 5:

1.

10. The device according to claim 3, wherein an upper one of said two convexly curved contour lines of said base sheet strip has a convex curvature in said central region, the convex curvature is higher than an elevation of said bonding wires connected to said contact connection areas extending beyond said bonding channel.

11. The device according to claim 2, wherein said laminate contains a porous plastic.

12. The device according to claim 2, wherein said laminate is constructed from a gas-tight plastic.

13. The device according to claim 2, wherein said bonding channel has a channel bottom and said contact areas of said chip are disposed at said channel bottom.

14. The device according to claim 2, wherein said laminate has a surface facing said flowable sheet strip and said contact connection areas, said conductor tracks and said soldering contact areas are disposed on said surface facing said flowable sheet strip.

15. The device according to claim 14, including a soldering mask layer disposed on said surface of said laminate facing said flowable sheet strip, said soldering mask layer partly covering said conductor tracks and leaving uncovered both said contact connection areas for bonding and said soldering contact areas for application of one of soldering bumps and soldering balls.

16. The device according to claim 2, including bonding pads having edge regions disposed in said bonding channel and said flowable sheet strip overlaps said edge regions of said bonding pads, said contact areas of said chip disposed one of along said bonding pads and in said bonding pads.

18. The method according to claim 17, which comprises forming the laminate as a porous laminate through which air cushions in the bonding channel escape during a softening of the sheet strip in the central region.

19. The method according to claim 17, which comprises carrying out the laminating of the sheet strip under a vacuum.

20. The method according to claim 17, which comprises using a heating iron to heat the central region of the sheet strip.

21. The method according to claim 17, which comprises using an infrared radiator to heat the central region of the sheet strip.

22. The method according to claim 17, which comprises using a scanned laser beam to laminate the edge regions of the sheet strip onto the edge regions of the bonding channel.

23. The method according to claim 17, which comprises using a composite sheet as the sheet strip formed of a shrink sheet strip as a covering sheet and a base sheet strip, after the lamination of the edge regions of the shrink sheet strip onto the edge regions of the bonding channel, using a scanned laser beam for heating the composite sheet resulting in the shrink sheet strip pressing a softened flowable central region of the sheet strip into the bonding channel with the bonding wires being embedded.

24. The method according to claim 17, which comprises disposing bonding pads in the bonding channels and the sheet strip overlapping edges of the bonding pads.

25. The method according to claim 24, which comprises laminating the edges of the sheet strip onto the edges of the bonding pads.

26. The method according to claim 25, which comprises using a scanned laser beam to laminate the edge regions of the sheet strip onto the edges of the bonding pads.

17. A method for producing an electronic device, which comprises the steps of:

providing a semiconductor chip having contact areas;

disposing a laminate on the semiconductor chip, the laminate having contact connection areas, conductor tracks and soldering contact areas, the laminate further having bonding channels formed therein for exposing a surface of the semiconductor chip on which the contact areas are disposed at a bottom of the bonding channel;

connecting the contact areas to the contact connection areas on the laminate using a bonding wire resulting in bonding wire connections;

positioning a sheet strip above the bonding channel with edge regions of the bonding channel being overlapped by edge regions of the sheet strip;

laminating the edge regions of the sheet strip onto the edge regions of the bonding channel, with the result that a convexly curved central region of the sheet strip arches over the bonding channel with the bonding wires;

heating the sheet strip to a flow temperature of the sheet strip causing a melting of the sheet strip in a central region resulting in a potting of the bonding wires; and

cooling the sheet strip in the bonding channel.

27. A sheet strip for covering bonding wire connections on bonding pads of an electronic device, comprising:

at least two preformed, mutually opposite edge regions covering edge regions of the bonding pads in an overlapping manner; and

a preformed central region extending between said opposite edge regions and having a bulge and a thickened portion, said central region further having two convexly curved contour lines in cross section.