Method and apparatus for removing known good die

• US 6,360,940 B1
• Filed: 11/08/2000
• Issued: 03/26/2002
• Est. Priority Date: 11/08/2000
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Olson, David, Johnson, Gregory M., Hennekens, James, Bolde, Lannie R.
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): JOHNSON, JONATHAN J
• Application Number:
  US09/709,092
• Time in Patent Office: 503 Days
• Field of Search: 228/119, 228/234.1, 228/264, 228/180.22, 228/201, 228/53, 228/19
• US Class Current: 228/264
• CPC Class Codes: B23K 1/018 Unsoldering; Removal of melted solder or other residues
• CPC Class Codes: H01L 21/67144 Apparatus for mounting on conductive members, e.g. leadframes or conductors on insulating substrates
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring

Abstract

Preferred embodiments for methods of removing an integrated circuit (“IC”) from a substrate, where the IC is attached to the substrate by multiple solder connections are disclosed. One preferred embodiment of the inventive methods provides the steps of heating the IC and substrate to the reflow temperature for the solder connections and pulling the IC from the substrate by means of a vacuum force. Another preferred embodiment of the inventive method provides the step of shearing the IC from the substrate after the substrate and IC are heated, but before solder reflow temperature has been reached, and where the shearing force may be programmed through a computer controlled servomotor. Preferred embodiments of certain apparatus applying the inventive methods for removing an integrated circuit from a substrate are also disclosed. One preferred embodiment of the inventive apparatus includes a vented pallet to hold the substrate and IC and through which the vacuum force is applied to pull the IC from the substrate without the use of physical clamping or contact forces applied to the substrate or IC. In a further preferred embodiment of the inventive apparatus, shear elements are provided and used with a programmable servomotor for precisely controlling the forces applied to the substrate and IC as a function of time, temperature and translational distance.

Claims

1. An apparatus for removing an integrated circuit from a substrate where said integrated circuit is attached to said substrate by a plurality of solder connection points, comprising:

a pallet having a cavity into which the substrate and integrated circuit fit, said pallet having a plurality of air channels formed in said pallet;

a heating plate, onto which the pallet, substrate and integrated circuit are placed to increase the temperature of the plurality of solder connection points to a reflow temperature; and

fluidic pulling means applied to the integrated circuit through the pallet plurality of air channels to remove the integrated circuit from the substrate after the plurality of solder connection points achieve a reflow temperature, said fluidic pulling means also maintaining the integrated circuit in the pallet cavity.

2. The apparatus for removing an integrated circuit from a substrate as provided in claim 1, wherein the pulling means is a vacuum applied to the integrated circuit through the pallet plurality of air channels.

3. The apparatus for removing an integrated circuit from a substrate as provided in claim 1, wherein the pulling means is a vacuum applied to both the substrate and the integrated circuit.

4. The apparatus for removing an integrated circuit from a substrate as provided in claim 1, further comprising a vacuum switch to shut off the vacuum upon release of the integrated circuit from the substrate.

5. The apparatus for removing an integrated circuit from a substrate as provided in claim 1, further comprising at least one sensor to shut off the vacuum upon release of the integrated circuit from the substrate.

6. The apparatus for removing an integrated circuit from a substrate as provided in claim 5, wherein the at least one sensor is a pressure sensor monitoring increases in vacuum pressure.

7. The apparatus for removing an integrated circuit from a substrate as provided in claim 1, further comprising a switch to shut off the heating plate upon release of the integrated circuit from the substrate.

8. The apparatus for removing an integrated circuit from a substrate as provided in claim 1, further comprising automatic operation of the pulling means as a plurality of pallets, substrates and integrated circuits are indexed through the apparatus.

9. The apparatus for removing an integrated circuit from a substrate as provided in claim 8, further comprising automatic operation of the indexing of the plurality of pallets, substrates and integrated circuits through the apparatus.

10. The apparatus for removing an integrated circuit from a substrate as provided in claim 1, wherein the pallet has a plurality of cavities into which the substrate and a plurality of integrated circuits fit.

11. The apparatus for removing an integrated circuit from a substrate as provided in claim 10 further comprising a plurality of pulling means each individually directed to the plurality of pallet cavities.

12. The apparatus for removing an integrated circuit from a substrate as provided in claim 10, further comprising a plurality of switches to individually control the plurality of pulling means.

13. The apparatus for removing an integrated circuit from a substrate as provided in claim 1, further comprising a cover to maintain the heating plate and pulling means in an oxygen reduced environment.

14. The apparatus for removing an integrated circuit from a substrate as provided in claim 1, further comprising a cover to maintain the heating plate and pulling means in a nitrogen enriched environment.