Sintered Metal Flip Chip Joints

• US 20170309549A1
• Filed: 04/21/2016
• Published: 10/26/2017
• Est. Priority Date: 04/21/2016
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Wachtler, Kurt Peter, Chae, Seunghyun, Cook, Benjamin Stassen
• Application Number:
  US15/135,318
• Publication Number:
  US 20170309549A1
• Time in Patent Office: Days
• CPC Class Codes: H01L 2021/60022 using bump connectors, e.g. for flip chip mounting
• CPC Class Codes: H01L 2224/0345 Physical vapour deposition [PVD], e.g. evaporation, or sputtering
• CPC Class Codes: H01L 2224/03462 Electroplating
• CPC Class Codes: H01L 2224/05647 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/11318 by dispensing droplets
• CPC Class Codes: H01L 2224/11332 using a powder
• CPC Class Codes: H01L 2224/11462 Electroplating
• CPC Class Codes: H01L 2224/1147 using a lift-off mask
• CPC Class Codes: H01L 2224/13017 being non uniform along the bump connector
• CPC Class Codes: H01L 2224/13076 being mutually engaged together, e.g. through inserts
• CPC Class Codes: H01L 2224/13082 Two-layer arrangements
• CPC Class Codes: H01L 2224/13124 Aluminium [Al] as principal constituent
• 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 2224/13155 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/13199 Material of the matrix
• CPC Class Codes: H01L 2224/13339 Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/13347 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/13386 with a principal constituent of the material being a non metallic, non metalloid inorganic material
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/81097 : Heating
• CPC Class Codes: H01L 2224/81191 : wherein the bump connectors are disposed only on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/81192 : wherein the bump connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/81193 : wherein the bump connectors are disposed on both the semiconductor or solid-state body and another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/8122 : with energy being in the form of electromagnetic radiation
• CPC Class Codes: H01L 2224/8184 : Sintering
• CPC Class Codes: H01L 2224/97 : the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 23/49503 : characterised by the die pad
• CPC Class Codes: H01L 23/49541 : Geometry of the lead-frame
• CPC Class Codes: H01L 23/49572 : consisting of thin flexible metallic tape with or without a film carrier H01L23/49503 - H01L23/49568 and H01L23/49575 - H01L23/49579 take precedence
• CPC Class Codes: H01L 23/5383 : Multilayer substrates H01L23/5385 takes precedence; multilayer metallisation on monolayer substrates H01L23/538
• CPC Class Codes: H01L 24/11 : Manufacturing methods for bumps on insulating substrates H01L21/4853
• CPC Class Codes: H01L 24/13 : of an individual bump connector
• CPC Class Codes: H01L 24/16 : of an individual bump connector
• CPC Class Codes: H01L 24/81 : using a bump connector
• 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 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/013 : Alloys
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/0541 : 11th Group
• CPC Class Codes: H01L 2924/05442 : SiO2
• CPC Class Codes: H01L 2924/181 : Encapsulation

Abstract

An integrated circuit die may be fabricating to have a plurality of contacts. A metal post may be formed on each of the plurality of contacts. A plurality of bumps may be formed on a plurality of contact regions of a leadframe or on the posts, in which the plurality of bumps are formed with a material that includes metal nanoparticles. The IC die may be attached to the leadframe by aligning the metal posts to the leadframe and sintering the metal nanoparticles in the plurality of bumps to form a sintered metal bond between each metal post and corresponding contact region of the leadframe.

Claims

1. A method for fabricating an integrated circuit, the method comprising:

fabricating an integrated circuit (IC) die having a plurality of contacts;

forming a metal post on each of the plurality of contacts;

forming a plurality of bumps on a plurality of contact regions of a leadframe or on the posts, in which the plurality of bumps are formed with a material that includes metal nanoparticles; and

attaching the IC die to the leadframe by aligning the metal posts to the leadframe and sintering the metal nanoparticles in the plurality of bumps to form a sintered metal bond between each metal post and corresponding contact region of the leadframe.

2. The method of claim 1, in which the sintering the metal nanoparticles forms a sintered metal bond that is porous.

3. The method of claim 2, in which the sintered metal bond has a porosity ranging from 0%-50%.

4. The method of claim 1, in which a portion of the plurality of bumps is formed on a portion of the posts and another portion of the plurality of bumps is formed on a portion of the contact regions of the leadframe.

5. The method of claim 1, in which forming the plurality of bumps is done by printing with an inkjet printer.

6. The method of claim 1, in which forming a metal post is done by printing with an inkjet printer.

7. The method of claim 1, in which sintering the metal nanoparticles is done by heating, by use of a Xenon flash tube, or by use of Formic acid.

8. The method of claim 1, in which the metal nanoparticles include copper nanoparticles and silver nanoparticles.

9. The method of claim 1, in which the metal nanoparticles include copper oxide nanoparticles.

10. The method of claim 1, in which the metal nanoparticles include copper nanoparticles and graphite nanoparticles.

11. An integrated circuit comprising:

an integrated circuit (IC) die with a plurality of contacts, in which a metal post is formed on each of the plurality of contacts; and

a leadframe, in which a plurality of contact regions on the lead frame are aligned with the plurality of contacts and metal posts and coupled thereto by sintered metal bonds.

12. The IC of claim 11, in which the sintered metal bonds are porous.

13. The IC of claim 12, in which the sintered metal bond has a porosity ranging from 0%-50%.

14. The IC of claim 11, in which the sintered metal bonds include copper nanoparticles and silver nanoparticles.

15. The IC of claim 11, in which the sintered metal bonds include copper oxide nanoparticles.

16. The IC of claim 11, in which the sintered metal bonds include copper nanoparticles and graphite nanoparticles.

17. An integrated circuit leadframe comprising:

a plurality of leads configured to couple to a plurality of contacts on an integrated circuit die; and

a plurality of bumps formed on the plurality of leads configured to align with the plurality of contacts on the integrated circuit die, in which the bumps are formed with a material that includes metal nanoparticles.

18. The leadframe of claim 17, in which the leadframe is a multi-layer substrate.

19. The leadframe of claim 17, in which the bumps have been sintered to form sintered metal bonds that are porous.

20. The leadframe of claim 17, in which the metal nanoparticles include copper nanoparticles and silver nanoparticles;

copper oxide nanoparticles;

or copper nanoparticles and graphite nanoparticles.