Wafer back side coating to balance stress from passivation layer on front of wafer and be used as die attach adhesive

• US 7,727,785 B2
• Filed: 11/07/2005
• Issued: 06/01/2010
• Est. Priority Date: 02/25/2002
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Connell, Michael E., Jiang, Tongbi
• Primary Examiner(s): Garber; Charles D
• Assistant Examiner(s): Stevenson; Andre' C
• Application Number:
  US11/269,069
• Publication Number:
  US 20060051938A1
• Time in Patent Office: 1,667 Days
• Field of Search: 438 14- 16, 438/21, 438/113, 438/200, 438/243, 438/613, 438/622, 438/597, 438/584, 438459-460, 438/462, 257/48, 257/632, 257620-621, 257/787, 257/737, 257/734, 257/669, 257/678, 356/600, 356/237.2
• US Class Current: 438/24
• CPC Class Codes: H01L 21/78 with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304
• CPC Class Codes: H01L 2224/03 Manufacturing methods
• CPC Class Codes: H01L 2224/94 at wafer-level, i.e. with connecting carried out on a wafer comprising a plurality of undiced individual devices
• CPC Class Codes: H01L 23/562 Protection against mechanical damage H01L23/02, H01L23/28 take precedence

Abstract

A method for balancing layer-caused compressive or tensile stress in a semiconductor die, die wafer or similar substrate uses a stress-balancing layer (SBL) attached to an opposite side from a stress-causing layer before the semiconductor die or wafer is significantly warped are provided. The SBL may also serve as, or support, an adhesive layer for die attach and be of a markable material for an enhanced marking method.

Claims

1. A manufacturing method for a wafer comprising:

grinding a front side of the wafer formed of semiconductor material comprising one of silicon, germanium, and gallium arsenide;

forming a plurality of circuits forming individual semiconductor devices on one side of the wafer;

applying a passivation layer over the plurality of circuits formed on the one side of the wafer;

reducing a cross-section of the wafer by thinning material from a another side of the wafer;

applying a stress-balancing layer to the another side of the wafer balancing the stress caused by the plurality of circuits on the one side of the wafer; and

singulating the wafer into at least one semiconductor die.

2. The method of claim 1, wherein the stress-balancing layer comprises a layer applied in fabrication of the at least one semiconductor die.

3. The method of claim 1, wherein the stress-balancing layer comprises a layer of passivation material.

4. The method of claim 1, wherein the reducing comprises grinding.

5. The method of claim 1, wherein the reducing comprises a chemical-mechanical method.

6. The method of claim 1, wherein the at least one semiconductor die comprises an integrated circuit semiconductor die.

7. The method of claim 1, wherein the stress-balancing layer comprises a strip covering a selected portion of a row of semiconductor dice on the wafer.

8. The method of claim 1, wherein the stress-balancing layer comprises a plurality of portions, each portion of the plurality of portions covering a selected portion of semiconductor dice on the wafer.

9. The method of claim 1, wherein a selected portion comprises a majority of the semiconductor dice.

10. The method of claim 1, wherein the stress-balancing layer comprises a heterogeneous composite structure comprising reinforcing particles in a solid matrix material.

11. The method of claim 10, wherein the reinforcing particles comprise inorganic particles.

12. The method of claim 10, wherein the reinforcing particles comprise one of a metal, an alloy, glass, and a combination thereof.

13. The method of with claim 10, wherein the reinforcing particles comprise particles for providing reinforcement in the X-Y plane of the stress-balancing layer.

14. The method of claim 10, wherein the reinforcing particles comprise particles for providing reinforcement in the X, Y, and Z directions.

15. The method of claim 10, wherein the solid matrix material comprises at least one material of silicon dioxide, silicon nitride, and an organic polymeric material.

16. The method of claim 1, wherein the at least one semiconductor die comprises one of a DIP, SIP, ZIP, PLCC, SOJ, SIMM, DJMM, LOC, QFP, SOP, TSOP, and a flip-chip.

17. The method of claim 1, wherein the stress-balancing layer comprises a material markable with indicia.

18. The method of claim 1, wherein the stress-balancing layer comprises a material markable by optical radiation energy.

19. The method of claim 1, wherein the stress-balancing layer comprises a polytetrafluoroethylene tape.

20. The method of claim 18, further comprising exposing at least a portion of the material markable with optical radiation energy to one of a Nd:

YAG (yttrium aluminum garnet), Nd;

YLP (pulsed yttrium fiber laser) or carbon dioxide laser for forming an indicia on the backside of the wafer.

21. A stress compensation method comprising:

grinding a front side of a wafer formed of semiconductor material comprising one of silicon, germanium, and gallium arsenide;

forming a plurality of circuits forming individual semiconductor devices on the front side of the wafer;

applying a passivation layer over the plurality of circuits formed on the front side of the wafer;

reducing a cross-section of a wafer by thinning a back side thereof;

applying a rigid stress-balancing layer to a portion of the thinned back side comprising a material for marking with indicia and for balancing stress caused by the passivation layer over the plurality of circuits;

exposing a portion of the semiconductor material to optical energy using one of a Nd;

YAG (yttrium aluminum garnet), Nd;

YLP (pulsed yttrium fiber laser) and carbon dioxide laser marking portions of a semiconductor die of the wafer on the back side thereof; and

singulating the wafer into at least one semiconductor die.

22. A force balancing method comprising:

placing a wafer of semiconductor material on a grinding apparatus;

grinding a front side of the wafer;

forming a plurality of circuits forming individual semiconductor devices on the front side of the wafer;

reducing a cross-section of a wafer by thinning a back side thereof;

applying a rigid stress-balancing layer comprising a material for marking with indicia to a portion of the thinned back side;

exposing a portion of the material to optical energy using one of a Nd;

YAG (yttrium aluminum garnet), Nd;

YLP (pulsed yttrium fiber laser) or carbon dioxide laser to mark portions of at least one semiconductor die of the wafer on the back side thereof with an indicia thereon by a portion of the material changing one of color or texture; and

singulating the wafer into at least one semiconductor die.

23. A planarization method for a semiconductor die comprising:

slicing a semiconductor ingot to form a semiconductor wafer;

grinding a front side of the wafer;

forming a plurality of circuits forming individual semiconductor devices on the front side of the wafer;

reducing a cross-section of a wafer by thinning material from a back side of the wafer;

applying a stress-balancing layer to the back side of the wafer for substantially balancing the stress caused by the plurality of circuits on the front side of the wafer and for creating a marking indicia on the other side of the wafer from one of a color change or texture change of the stress-balancing layer;

and

singulating the wafer into at least one semiconductor die.