Method and apparatus for wafer-level burn-in

• US 6,627,917 B1
• Filed: 04/25/2000
• Issued: 09/30/2003
• Est. Priority Date: 04/25/2000
• Status: Expired due to Fees

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Gerrish, Paul F., Bell, James W., Fulton, Daniel E., Larson, Lary R., Fenner, Andreas A., May, James Thomas
• Primary Examiner(s): Pham, Long
• Assistant Examiner(s): NGUYEN, DILINH P
• Application Number:
  US09/557,508
• Time in Patent Office: 1,253 Days
• Field of Search: 257/48, 257/529, 257/665, 257/735-736, 257/619-620, 257/688, 438/17, 438/18, 438/132, 438/601, 438/68-72, 438/113-114, 438/450, 438/458, 438/461-465
• US Class Current: 257/48
• CPC Class Codes: G01R 31/2831 Testing of materials or semi-finished products, e.g. semiconductor wafers or substrates G01R31/318511 takes precedence; testing during manufacture H01L22/00
• CPC Class Codes: G01R 31/316 Testing of analog circuits G01R31/2851 takes precedence

Abstract

Methods and apparatus for burn-in of integrated circuit (IC) dies at the wafer level. In one embodiment, a wafer is fabricated having an array of dies formed thereon wherein the dies are separated by scribe areas. Surrounding each die is one or more ring conductors which are electrically coupled to various circuits on the die via die bond pads. The wafer further includes a series of conductive pads located in an inactive region of the wafer. Electrically connecting the conductive pads to the ring conductors is a series of redundant scribe conductors. During burn-in, a burn-in indicating apparatus located on each die monitors burn-in parameters such as elapsed burn-in time. The indicating apparatus further records the elapsed burn-in time (or other parameter). The indicating apparatus may be subsequently interrogated to verify the burn-in time.

Claims

1. A semiconductor wafer comprising:

one or more conductive pads located in an inactive region of the wafer wherein the conductive pads are adapted to electrically couple to an external power supply;

a plurality of dies in an active region of the wafer wherein each die includes a burn-in indicating apparatus, the burn-in indicating apparatus adapted to indicate a burn-in parameter;

an array of scribe lines separating the plurality of dies, wherein the scribe lines include one or more scribe conductors electrically coupling the one or more conductive pads to circuits of the plurality of dies;

one or more conductive rings surrounding each die, wherein the one or more scribe conductors connects to the one or more conductive rings and the conductive rings, in turn, connect via die bond pads to the circuits of the plurality of dies.

2. A semiconductor wafer which permits simultaneous burn-in of all the dies on the wafer, the wafer comprising:

one or more conductive pads located in an inactive region of the wafer wherein the conductive pads are adapted to electrically couple to an external power supply;

a plurality of dies located in an active region of the wafer;

a burn-in indicating apparatus associated with each die of the plurality of dies, the burn-in indicating apparatus adapted to monitor one or more burn-in parameters;

scribe areas separating the plurality of dies;

one or more conductive rings surrounding each die, wherein the conductive rings are electrically coupled to die bond pads on each die; and

scribe conductors within the scribe areas, wherein the scribe conductors electrically couple the one or more conductive pads to the one or more conductive rings.

3. The wafer of claim 2, wherein the scribe conductors comprise bridges which extend across the scribe areas between the conductive rings of adjacent dies.

4. The wafer of claim 2, wherein the scribe conductors redundantly interconnect the conductive pads to the conductive rings.

5. The wafer of claim 2, wherein the scribe conductors comprise polysilicon.

6. The wafer of claim 2, wherein the scribe conductors are formed at or near a first surface of the wafer.

7. The wafer of claim 2, wherein the one or more burn-in parameters is a period of time for which power is provided to the die by the external power supply.

8. The wafer of claim 2, wherein the one or more burn-in parameters is a period of time for which one or more circuits on the die is operating.

9. The wafer of claim 2, wherein the burn-in indicating apparatus comprises a one-bit counter adapted to switch when a pre-determined period of burn-in time has elapsed.

10. The wafer of claim 2, wherein the burn-in indicating apparatus comprises a memory device adapted to record the one or more burn-in parameters.

11. The wafer of claim 10, wherein the memory device comprises one or more fuses.

12. The wafer of claim 10, wherein the memory device is a programmable memory device.

13. A semiconductor wafer which permits simultaneous burn-in of all the dies on the wafer, the wafer comprising:

one or more conductive pads located on the wafer, wherein the conductive pads are adapted to couple to an external power supply; and

a plurality of dies, wherein the plurality of dies includes one or more circuits, and wherein substantially each die of the plurality of dies comprises;

a burn-in indicating apparatus, the burn-in indicating apparatus adapted to monitor one or more burn-in parameters; and

die bond pads on a face of the die, the die bond pads electrically coupled to the one or more circuits and the burn-in indicating apparatus and further electrically coupled to the one or more conductive pads;

and further comprising;

one or more conductive rings surrounding each die, wherein the conductive rings are electrically coupled to selected die bond pads; and

one or more scribe conductors electrically coupled to both the one or more conductive rings and the one or more conductive pads.

14. A semiconductor wafer which permits simultaneous burn-in of all the dies on the wafer, the wafer comprising:

one or more conductive pads located on the wafer, wherein the conductive pads are adapted to couple to an external power supply; and

a plurality of dies, wherein the plurality of dies includes one or more circuits, and wherein substantially each die of the plurality of dies comprises;

a burn-in indicating apparatus, the burn-in indicating apparatus adapted to monitor one or more burn-in parameters; and

further comprising die bond pads on a face of the die, the die bond pads electrically coupled to the one or more circuits and the burn-in indicating apparatus and further electrically coupled to the one or more conductive pads; and

further comprising;

one or more conductive rings surrounding each die, wherein the conductive rings are electrically coupled to selected die bond pads; and

one or more scribe conductors electrically coupled to both the one or more conductive rings and the one or more conductive pads; and

wherein the conductive rings are electrically coupled to the die bond pads with a resistor.

15. A semiconductor wafer which permits simultaneous burn-in of all the dies on the wafer, the wafer comprising:

one or more conductive pads located on the wafer, wherein the conductive pads are adapted to couple to an external power supply; and

a plurality of dies, wherein the plurality of dies includes one or more circuits, and wherein substantially each die of the plurality of dies comprises;

a burn-in indicating apparatus, the burn-in indicating apparatus adapted to monitor one or more burn-in parameters; and

further comprising die bond pads on a face of the die, the die bond pads electrically coupled to the one or more circuits and the burn-in indicating apparatus and further electrically coupled to the one or more conductive pads; and

further comprising;

one or more conductive rings surrounding each die, wherein the conductive rings are electrically coupled to selected die bond pads; and

one or more scribe conductors electrically coupled to both the one or more conductive rings and the one or more conductive pads and;

wherein the conductive rings are electrically coupled to the die bond pads with a diode.