Packaging structure and method

• US 20060255474A1
• Filed: 06/01/2006
• Published: 11/16/2006
• Est. Priority Date: 03/10/2000
• Status: Abandoned Application

• Current Assignee: Chippac Company Limited
• Original Assignee: Chippac Company Limited
• Inventors: Tam, Samuel, Kweon, Young-Do, Pendse, Rajendra D., Kim, Kyung-Moon, Ahmad, Nazir
• Application Number:
  US11/444,894
• Publication Number:
  US 20060255474A1
• Time in Patent Office: Days
• US Class Current: 257/778
• 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 2224/10135 Alignment aids
• CPC Class Codes: H01L 2224/1134 Stud bumping, i.e. using a wire-bonding apparatus
• CPC Class Codes: H01L 2224/13144 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/13147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/16145 the bodies being stacked
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/29111 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/29144 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/2919 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/73203 Bump and layer connectors
• CPC Class Codes: H01L 2224/81139 Guiding structures on the body
• CPC Class Codes: H01L 2224/81203 Thermocompression bonding, e.g. diffusion bonding, pressure joining, thermocompression welding or solid-state welding
• CPC Class Codes: H01L 2224/81801 Soldering or alloying
• CPC Class Codes: H01L 2224/83102 using surface energy, e.g. capillary forces
• CPC Class Codes: H01L 2224/83191 wherein the layer connectors are disposed only on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83194 Lateral distribution of the layer connectors
• CPC Class Codes: H01L 2224/92125 the second connecting process involving a layer connector
• CPC Class Codes: H01L 24/29 of an individual layer connector
• CPC Class Codes: H01L 24/81 using a bump 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 2924/00012 : 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 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01058 : Cerium [Ce]
• CPC Class Codes: H01L 2924/01076 : Osmium [Os]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/0132 : Binary Alloys
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/07802 : not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/181 : Encapsulation

Abstract

A method for forming metallurgical interconnections and polymer adhesion of a flip chip to a substrate includes providing a chip having a set of bumps formed on a bump side thereof and a substrate having a set of interconnect points on a metallization thereon, providing a measured quantity of a polymer adhesive in a middle region of the chip on the bump side, aligning the chip with the substrate so that the set of bumps aligns with the set of interconnect points, pressing the chip and the substrate toward one another so that a portion of the polymer adhesive contacts the substrate and the bumps contact the interconnect points, and heating the bumps to a temperature sufficiently high to form a metallurgical connection between the bumps and the interconnect points. Also, a flip chip package is made by the method. In some embodiments the metallurgical connection includes an alloy of gold and tin at the interface between the bumps and the interconnect points.

Claims

1. A method for providing metallurgic connection between a flip chip and a substrate comprises

providing a chip having a set of bumps formed on a bump side thereof;

providing a substrate having a set of interconnect points on a metallization thereon;

providing a measured quantity of a polymer adhesive in a middle region of the chip on the bump side;

aligning the chip with the substrate so that the set of bumps aligns with the set of interconnect points;

pressing the chip and the substrate toward one another so that a portion of the polymer adhesive contacts the substrate and the bumps contact the interconnect points; and

heating the bumps to a temperature sufficiently high to form a metallurgical connection between the bumps and the interconnect points.

2. The method of claim 1 wherein the bumps are stud bumps.

3. The method of claim 1 wherein the bumps comprise gold.

4. The method of claim 1 wherein the bumps are plated with a metal comprising gold.

5. The method of claim 1 wherein the interconnect points comprise tin.

6. The method of claim 5 wherein the interconnect points comprise pure tin.

7. The method of claim 1 wherein the interconnect points comprise a metal plated with a metal comprising gold.

8. The method of claim 1 wherein the bumps are stud bumps comprising Au and the interconnect points comprise Sn, and the heating step raises the temperature of the bumps sufficiently to create an alloy between the Au and the Sn in a bonding phase at the interface.

9. The method of claim 8 wherein the heating step raises the temperature of the bumps sufficiently to create an alloy comprising a 80:

20 Au;

Sn between in a bonding phase at the interface.

10. The method of claim 1 wherein the heating step raises the die to a temperature greater than about 200°

C.

11. The method of claim 1 wherein the heating step raises the die to a temperature about 232°

C.

12. The method of claim 1, further comprising underfilling with a polymer.

13. A chip package structure made according to the method of claim 12.

14. A chip package structure comprising

a chip having a bumps formed thereon and a substrate having interconnect points on a metallization thereon, the bumps forming contacts with the interconnect points, wherein an alloy is formed at an interface between the material of each bump and the material of the interconnect in contact with the bump.

15. The chip package structure of claim 14 wherein a cured adhesive polymer is situated in a middle region between the bump surface of the chip and the surface of the substrate.

16. The chip package structure of claim 14 wherein the bump material comprises gold and the interconnect points comprise Sn, and the alloy at the interface comprises a Au/Sn alloy.

17. The chip package structure of claim 16 wherein the alloy at the interface is a 20:

80 Sn;

Au alloy.