Method of forming a permanent carrier and spacer wafer for wafer level optics and associated structure

• US 7,888,758 B2
• Filed: 03/12/2008
• Issued: 02/15/2011
• Est. Priority Date: 03/12/2008
• Status: Active Grant

• Current Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Original Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Inventors: Lake, Rickie C.
• Primary Examiner(s): POTTER, ROY KARL
• Application Number:
  US12/073,998
• Publication Number:
  US 20090231826A1
• Time in Patent Office: 1,070 Days
• Field of Search: 361/820, 438/65, 257/E31.122, 257/431, 257/433, 257/443, 257/432, 257/292, 257/444, 257/460
• US Class Current: 257/433
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14683 Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof not peculiar thereto H01L21/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A carrier wafer for wafer level fabrication of imager structures comprising a substrate with trenches corresponding to locations of imager arrays on an imager wafer. A method of fabricating such a carrier wafer and a method of fabricating an imager module employing such a carrier wafer are also provided.

Claims

1. A method of forming an imager structure, the method comprising:

etching trenches in a carrier substrate;

filling the trenches at least partially with a dissolvable material;

bonding an imager wafer to the carrier substrate, the imager wafer comprising imager arrays, each imager array being associated with and aligned within a respective trench and being spaced from the carrier substrate; and

removing the dissolvable material.

2. The method of claim 1, further comprising:

removing portions of the carrier substrate within the trenches; and

affixing a lens element above the imager array to the remaining carrier substrate.

3. The method of claim 2, wherein the carrier substrate is thinned to a thickness corresponding to a desired distance between the lens element and the imager array.

4. The method of claim 1, wherein the carrier substrate has a thickness within the range of approximately 650 to approximately 850 microns.

5. The method of claim 1, wherein the trenches have, a width within the range of approximately 50 to approximately 100 microns and have a depth within the range of approximately 400 to approximately 600 microns.

6. The method of claim 1, wherein the step of filling the trenches at least partially with a dissolvable material further comprises removing air pockets within the dissolvable material.

7. The method of claim 1, wherein the dissolvable material is a soluble adhesive.

8. The method of claim 7, wherein the dissolvable material is a solvent-soluble adhesive.

9. The method of claim 7, wherein the dissolvable material is a water-soluble adhesive.

10. A method of forming an imager structure, the method comprising:

etching trenches in a first wafer, the trenches forming perimeters around inner areas corresponding to imager arrays on an imager wafer;

placing a dissolvable material in the trenches;

applying a bonding material to outer areas of at least one of the first wafer and the imager wafer;

aligning the first wafer and the imager wafer, such that the imager arrays are aligned within the perimeters of the trenches;

bonding the first wafer and the imager wafer;

processing a backside of the imager wafer; and

removing the dissolvable material and portions of the first wafer within a periphery of the trenches.

11. The method of claim 10, wherein the dissolvable material is a solvent-soluble adhesive.

12. The method of claim 10, wherein the dissolvable material is a water-soluble adhesive.

13. The method of claim 10, wherein the trenches are rectangular-shaped.

14. The method of claim 10, wherein the trenches are circular-shaped.

15. The method of claim 10, wherein the trenches have a depth less than a first thickness of the first wafer, and the method further comprises:

thinning the first wafer to a second thickness, the second thickness being less than or equal to the depth of the trenches; and

attaching respective lens structures to remaining portions of the first wafer at locations corresponding to the imager arrays.

16. A carrier wafer comprising:

a substrate having a thickness;

a plurality of trenches etched to form perimeters around a plurality of areas on the, substrate, the trenches corresponding to respective perimeters of imager arrays on an imager wafer, the trenches having a depth less than the thickness of the substrate; and

a dissolvable material within the trenches.

17. The carrier wafer of claim 16, wherein the trenches have a width within the range of approximately 50 microns to approximately 100 microns.

18. The carrier wafer of claim 16, wherein the trenches have a depth within the range of approximately 400 microns to approximately 600 microns.

19. The carrier wafer of claim 16, wherein the trenches are at least partially filled with a solvent-soluble adhesive.

20. An intermediate structure for use in fabrication, the intermediate structure comprising:

a substrate having a thickness; and

at least one trench etched in the substrate corresponding to a location of a component on a separate structure, the at least one trench encircling a volume of the substrate.

21. The intermediate structure of claim 20, the at least one trench having:

sidewalls that are substantially vertical; and

a depth less than the thickness of the substrate.

22. The intermediate structure of claim 20, wherein the at least one trench corresponds to a location of an imager array on an imager wafer.

23. The intermediate structure of claim 22, wherein the volume has a surface area corresponding to a surface area of the imager array.

24. The intermediate structure of claim 20, wherein the at least one trench is rectangular-shaped.

25. An intermediate structure for use in imager module fabrication, the intermediate structure comprising:

a substrate having a thickness; and

at least one trench etched in the substrate, the at least one trench encircling a volume of the substrate, wherein the at least one trench is circular-shaped.