Micromachine stacked flip chip package fabrication method

• US 6,530,515 B1
• Filed: 09/26/2000
• Issued: 03/11/2003
• Est. Priority Date: 09/26/2000
• Status: Active Grant

• Current Assignee: Amkor Technology Singapore Holding Pte., Ltd. (Amkor Technology Incorporated)
• Original Assignee: Amkor Technology Incorporated
• Inventors: Webster, Steven, Glenn, Thomas P., Hollaway, Roy Dale
• Primary Examiner(s): Elve, M. Alexandra
• Assistant Examiner(s): Tran, Len
• Application Number:
  US09/670,501
• Time in Patent Office: 896 Days
• Field of Search: 228/180.21, 228/180.22, 228/234.1, 228/215, 228/135, 228/214, 257/737, 257/738, 438/613, 438/614, 438/615, 438/616
• US Class Current: 228/214
• CPC Class Codes: B81B 7/0077 Other packages not provided for in groups B81B7/0035 - B81B7/0074
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• 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 2924/16235 Connecting to a semiconductor or solid-state bodies, i.e. cap-to-chip
• CPC Class Codes: H01L 2924/181 Encapsulation

Abstract

To form a micromachine package, bond pads on a front surface of a controller chip are aligned with corresponding traces on a front surface of a micromachine chip. The bond pads are physically connected to the traces thus mounting the controller chip as a flip chip to the micromachine chip. A bead is formed around a periphery of the controller chip. The bead and the controller chip form an enclosure around a micromachine area in the front surface of the micromachine chip. This enclosure protects the micromachine area from the ambient environment.

Claims

1. A method of protecting a first active area in a first surface of a first chip comprising:

aligning a first bond pad on a first surface of a second chip with a first trace on said first surface of said first chip;

physically connecting said first bond pad to said first trace, wherein said first active area is a micromachine area comprising a miniature moveable structure; and

forming a bead around a periphery of said second chip, wherein said first chip, said second chip, and said bead form an enclosure which defines a cavity, said first active area being located within said cavity.

2. The method of claim 1 wherein said physically connecting comprises:

forming a flip chip bump on said first bond pad; and

reflowing said flip chip bump.

3. The method of claim 1 wherein said physically connecting comprises:

forming a flip chip bump on said first trace; and

reflowing said flip chip bump.

4. The method of claim 1 wherein said first bond pad is physically connected to said first trace by a flip chip bump.

5. The method of claim 4 wherein said flip chip bump is formed of a material selected from the group consisting of solder, gold, electrically conductive epoxy paste and electrically conductive epoxy film.

6. The method of claim 1 wherein said physically connecting comprises directly connecting said first bond pad to said first trace.

7. The method of claim 6 wherein said directly connecting comprises thermo-compression bonding said first bond pad to said first trace.

8. The method of claim 1 wherein said forming a bead comprises:

dispensing a limited flow material around said second chip, wherein said limited flow material is drawn slightly between said first chip and said second chip; and

curing said limited flow material.

9. The method of claim 8 wherein said limited flow material comprises a liquid encapsulant.

10. The method of claim 1 wherein said second chip comprises a second active area in said first surface of said second chip, said second active area being located within said cavity.

11. The method of claim 1 wherein said first chip is a micromachine chip.

12. The method of claim 11 wherein said second chip is a controller chip.

13. The method of claim 1 further comprising electrically connecting said first trace to a first lead.

14. The method of claim 1 further comprising forming a bond wire between said first trace and a first lead.

15. The method of claim 12 wherein said controller chip is a controller for said micromachine chip.

16. The method of claim 1 wherein said first trace extends from said first active area to a periphery of said first surface of said first chip adjacent bond pads of said first chip.

17. A method of forming a package comprising a first chip and a second chip, said method comprising:

aligning a first bond pad on a first surface of said second chip with a first trace on a first surface of said first chip, a first active area being in said first surface of said second chip, wherein said first active area is a micromachine area comprising a miniature moveable structure;

physically connecting said first bond pad to said first trace; and

forming a bead around a periphery of said second chip, wherein said first chip, said second chip, and said bead form an enclosure which defines a cavity, said first active area being located within said cavity.

18. A method of forming a package comprising a first micromachine chip and a second micromachine chip comprising:

aligning a first bond pad on a first surface of said second micromachine chip with a first trace on a first surface of said first micromachine chip, said first trace extending from a first micromachine area of said first micromachine chip to a periphery of said first surface of said first micromachine chip adjacent bond pads of said first micromachine chip;

physically connecting said first bond pad to said first trace; and

forming a bead around a periphery of said second micromachine chip to form an enclosure which defines a cavity, said first micromachine area of said first micromachine chip and a second micromachine area of said second micromachine chip being located within said cavity.