Transfer molding of integrated circuit packages

• US 20050275091A1
• Filed: 08/22/2005
• Published: 12/15/2005
• Est. Priority Date: 06/15/2001
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Paquet, Marie-Claude, Boyaud, Marie-France, Dufort, Catherine, Tetreault, Real
• Granted Patent: US 6,988,882 B2
• Time in Patent Office: Days
• US Class Current: 257/731
• CPC Class Codes: H01L 21/563 Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• CPC Class Codes: H01L 21/565 Moulds
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/83104 by applying pressure, e.g. by injection
• CPC Class Codes: H01L 23/3128 the substrate having spherical bumps for external connection
• 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 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/1815 Shape

Abstract

A method, mold and apparatus for encapsulating and underfilling an integrated circuit chip assembly. The mold has a first portion and a second portion with the first portion having first and second cavities and at least one channel interconnecting said first and second cavities. The first cavity is adapted to enclose said integrated circuit chip on said substrate. A clamping force is applied to the first and second portions of the mold to clamp the substrate between them with the integrated circuit chip located in the first cavity. Vents exhaust air from the first cavity. Encapsulant is injected into the first cavity of the first portion at a location in the first portion remote from the point of connection of the channel such that encapsulant flows around and underneath the integrated circuit chip and through the channel into the second cavity to thereby underfill and encapsulate the integrated circuit assembly.

Claims

1. A mold for encapsulating and underfilling an integrated circuit chip assembly including an integrated circuit chip mounted on a substrate in a standoff relationship, said mold comprising:

a first mold portion having first and second cavities and a channel interconnecting said first and second cavities, said first cavity being adapted for enclosing said integrated circuit chip on said substrate;

a second mold portion;

said first and second mold portions being adapted to clamp the substrate between the first and second portions with the integrated circuit chip located within said first cavity;

a vent for exhausting air from said first cavity; and

injecting structure for injecting encapsulant into said first cavity of said first mold portion at two spaced locations in said first portion remote from the point of connection of said channel to said first cavity generally in the direction toward said channel, such that encapsulant flows around and underneath said integrated circuit chip and through said channel into said second cavity to thereby underfill and encapsulate said integrated circuit assembly.

2. A mold for encapsulating and underfilling an integrated circuit chip assembly according to claim 1 wherein said injecting structure includes first and second inlet gates such that said first inlet gate is located over said integrated circuit chip and said second inlet gate is located beside said integrated circuit chip.

3. A mold for encapsulating and underfilling an integrated circuit chip assembly according to claim 1 wherein said first and second mold portions are upper and lower mold portions respectively.

4. A mold for encapsulating and underfilling an integrated circuit chip assembly according to claim 1 wherein said injecting structure also causes encapsulant to flow over said integrated circuit chip.

5. A mold for encapsulating and underfilling an integrated circuit chip assembly according to claim 1 wherein said vent also is adapted for exhausting air from said second cavity.

10. The invention as defined in claim 1, wherein one of said locations for injecting encapsulant being in the vicinity of the top of the integrated circuit chip, and the other location being in the vicinity of the space between the integrated circuit chip and the substrate, such that encapsulant flows around and underneath the integrated circuit chip and through the channel into said second cavity to thereby underfill and encapsulate said integrated circuit assembly.

11. The invention according to claim 1 wherein said integrated circuit chip is a flip chip having contacts on one side thereof interconnected with contacts on one side of said substrate by solder balls.

13. The invention according to claim 1 including a vacuum device positioned to draw air from within said first and second cavities.

6. Apparatus for encapsulating and underfilling an integrated circuit chip assembly including an integrated circuit chip mounted on a substrate in a standoff relationship, said apparatus comprising:

a mold having a first portion and a second portion;

said first portion having first and second cavities and at least one channel interconnecting said first and second cavities;

said first cavity being adapted to enclose said integrated circuit chip on said substrate;

a vent for exhausting air from said first cavity; and

injecting structure for injecting encapsulant into said first cavity of said first portion at two spaced locations in said first portion remote from the point of connection of said at least one channel to said first cavity generally in the direction toward said at least one channel, such that encapsulant flows around and underneath the integrated circuit chip and through at least one channel into said second cavity to thereby underfill and encapsulate said integrated circuit assembly.

7. Apparatus according to claim 6 in which said first and second portions of the mold are upper and lower portions, respectively, of said mold.

8. Apparatus according to claim 6 wherein said vent is also adapted for exhausting air from said second cavity.

9. Apparatus according to claim 6 wherein said injecting structure for injecting encapsulant into said first cavity includes first and second inlet gates wherein said first inlet gate is located over said integrated circuit chip and said second inlet gate is located beside said integrated circuit chip.

12. The invention according to claim 6 wherein said integrated circuit chip is a flip chip having contacts on one side thereof interconnected with contacts on one side of said substrate by solder balls.

14. The invention according to claim 6 including a vacuum device positioned to draw air from within said first and second cavities

15. A mold for encapsulating and underfilling an integrated circuit chip assembly according to claim 6 wherein said injecting structure also causes encapsulant to flow over said integrated circuit chip.

16. The invention as defined in claim 6, wherein one of said locations for injecting encapsulant being in the vicinity of the top of the integrated circuit chip, and the other location being in the vicinity of the space between the integrated circuit chip and the substrate, such that encapsulant flows around and underneath the integrated circuit chip and through the channel into said second cavity to thereby underfill and encapsulate said integrated circuit assembly.