Flip-chip system and method of making same

• US 6,724,091 B1
• Filed: 10/24/2002
• Issued: 04/20/2004
• Est. Priority Date: 10/24/2002
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Jayaraman, Saikumar, Wakharkar, Vijay S.
• Primary Examiner(s): POTTER, ROY KARL
• Application Number:
  US10/279,477
• Time in Patent Office: 544 Days
• Field of Search: 257/778, 257/737, 257/738, 428/131, 438/108
• US Class Current: 257/778
• CPC Class Codes: C08G 59/3254 containing atoms other than carbon, hydrogen, oxygen or nitrogen
• 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 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/13111 Tin [Sn] as principal constituent
• 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 2224/2919 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/73203 Bump and layer connectors
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/83102 using surface energy, e.g. capillary forces
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/92125 the second connecting process involving a layer connector
• CPC Class Codes: H01L 23/293 Organic, e.g. plastic
• CPC Class Codes: H01L 24/29 of an individual layer connector
• CPC Class Codes: H01L 24/743 Apparatus for manufacturing layer connectors
• 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 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01032 : Germanium [Ge]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01039 : Yttrium [Y]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01057 : Lanthanum [La]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/0132 : Binary Alloys
• CPC Class Codes: H01L 2924/0133 : Ternary Alloys
• CPC Class Codes: H01L 2924/0665 : Epoxy resin
• CPC Class Codes: H01L 2924/10329 : Gallium arsenide [GaAs]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/3512 : Cracking

Abstract

A system for underfilling in a chip package includes an underfill mixture that ameliorates the CTE mismatch that typically exists between a packaged die and a resin-impregnated fiberglass mounting substrate. In one embodiment, the system includes an underfill mixture that alone exhibits a CTE that is characteristic of an inorganic-filled underfill composite previously known. An embodiment is also directed to the assembly of a flip-chip package that uses an underfill mixture.

Claims

1. A packaging system comprising:

a flip-chip on a mounting substrate;

an underfill mixture between the flip-chip and the mounting substrate, wherein the underfill mixture includes a principal underfill composition selected from silesquioxanes, thermosetting liquid crystal monomers, and combinations thereof.

2. The packaging system according to claim 1, wherein the underfill mixture further includes:

at least one additive material selected from an elastomer, a hardener/crosslinker, a catalyst, a reactive diluent, an adhesion promoter, a surfactant, a deforming agent, a fluxing agent, and a toughening agent.

3. The packaging system according to claim 1, wherein the underfill mixture further includes:

at least one additive material selected from an elastomer, a hardener/crosslinker, a catalyst, a reactive diluent, an adhesion promoter, a surfactant, a deforming agent, a fluxing agent, and a toughening agent; and

wherein the underfill mixture is a single phase material.

4. The packaging system according to claim 1, wherein the underfill mixture further includes:

at least one additive material selected from an elastomer, a hardener/crosslinker, a catalyst, a reactive diluent, an adhesion promoter, a surfactant, a deforming agent, a fluxing agent, a toughening agent, and an inorganic particulate.

5. The packaging system according to claim 1, wherein the principal underfill composition is a functionalized silesquioxane, including a functional group selected from an epoxy, an alcohol, a phenol, an amine, an epoxide, an ester an isocyanate, a methacrylate, an acrylate, a norbornenyl, an olefin, a styrene, and a hydroxide.

6. The packaging system according to claim 1, wherein the principal underfill composition is an epoxy-functionalized silesquioxane that is functionalized in a range from about 1 to about 10.

7. The packaging system according to claim 1, wherein the principal underfill composition is an epoxy-functionalized silesquioxane that is functionalized in a range from about 3 to about 7.

8. The packaging system according to claim 1, wherein the principal underfill composition is an epoxy-functionalized silesquioxane that is functionalized to about 5.

9. The packaging system according to claim 1, wherein the principal underfill composition is an epoxy-functionalized silesquioxane that is functionalized in a range from about 1 to about 10, and further including:

a second epoxy selected from bi-phenyl epoxy, bis-phenol A epoxy, bis-phenol F epoxy, and a cycloaliphatic epoxy; and

at least one additive material selected from an elastomer, a hardener/crosslinker, a catalyst, a reactive diluent, an adhesion promoter, a surfactant, a deforming agent, a fluxing agent, a toughening agent, and an inorganic particulate.

10. The packaging system according to claim 1, wherein the principal underfill composition is a thermoset liquid crystalline compound, that is functionalized by a functional group selected from an epoxy, an alcohol, a phenol, an amine, an epoxide, an ester, an isocyanate, a methacrylate, an acrylate, a norbornenyl, an olefin, a styrene, and a hydroxide.

11. The packaging system according to claim 1, wherein the principal underfill composition is a thermoset liquid crystalline compound that is a diglycidyl ether of dihydroxy alpha methylstilene (DHAMS).

12. The packaging system according to claim 1, wherein the flip-chip is coupled to the mounting substrate through a conductive bump, and wherein the conductive bump includes a Pb-free solder.

20. The packaging system of claim 1, wherein the principal underfill composition includes a silesquioxane mixed with a Bis F epoxy monomer, an anhydride hardener, carboxy-terminated polybutadiene-acrylonitrile elastomer, and a catalyst.

21. The packaging system of claim 1, wherein the principal underfill composition includes a silesquioxane mixed with a Bis F epoxy monomer, an amine hardener, carboxy-terminated polybutadiene-acrylonitrile elastomer, and a catalyst.

22. The packaging system of claim 10, wherein the principal underfill composition is functionalized in a range from about 1 to about 10.

23. The packaging system of claim 10, wherein the principal underfill composition is functionalized in a range from about 3 to about 7.

24. The packaging system of claim 10, wherein the principal underfill composition is functionalized to about 5.

13. A chip package comprising:

a chip including an active surface;

a mounting substrate including an upper surface that faces the active surface;

electrical coupling between the active surface and upper surface; and

an underfill mixture between the upper surface and the active surface, wherein the underfill mixture includes a principal underfill composition selected from silesquioxanes, thermosetting liquid crystal monomers, and combinations thereof; and

wherein the underfill mixture includes at least one property selected from about 12.5 KSI tensile strength, a coefficient of thermal expansion less than about 60 ppm/°

C., and a glass transition temperature greater than about 300°

C.

14. The chip package according to claim 13, further including:

an inorganic filler in the underfill mixture that forms an inorganic-filled underfill composite.

15. The chip package according to claim 13, wherein the underfill mixture is a single-phase mixture.

16. The chip package according to claim 13, wherein the underfill mixture includes a functionalized silesquioxane, and further including:

at least one additive selected from an elastomer, a hardener/crosslinker, a catalyst, a reactive diluent, an adhesion promoter, a surfactant, a deforming agent, a fluxing agent, and a toughening agent; and

at least one of a non-silesquioxane oligomer and a non-silesquioxane polymer.

17. The chip package according to claim 13, wherein the underfill mixture includes a functionalized silesquioxane, and further including:

at least one of a non-silesquioxane oligomer and a non-silesquioxane polymer.

18. The chip package according to claim 13, wherein the underfill mixture includes a thermoset liquid crystal oligomer or polymer, and further including:

at least one additive selected from an elastomer, a hardener/crosslinker, a catalyst, a reactive diluent, an adhesion promoter, a surfactant, a deforming agent, a fluxing agent, and a toughening agent.

19. The chip package according to claim 13, wherein the electrical coupling includes a Pb-free solder.