METHOD AND APPARATUS PROVIDING COMBINED SPACER AND OPTICAL LENS ELEMENT

• US 20100244165A1
• Filed: 03/26/2009
• Published: 09/30/2010
• Est. Priority Date: 03/26/2009
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Duparre, Jacques, Lake, Rick
• Granted Patent: US 8,450,821 B2
• Time in Patent Office: Days
• US Class Current: 257/432
• CPC Class Codes: G02B 13/0085 employing wafer level optics
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 3/0075 characterized by non-optical structures, e.g. having integrated holding or alignment means
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements

Abstract

A method and apparatus used for forming a lens and spacer combination, and imager module employing the spacer and lens combination. The apparatus includes a mold having a base, spacer section, and mold feature. The method includes using the mold with a blank to create a spacer that includes an integral lens. The spacer and lens combination and imager modules can be formed on a wafer level.

Claims

1. A mold for forming a combination spacer lens wafer, the mold comprising:

a base;

a mold feature; and

a spacer section connecting the base to the mold feature.

2. The mold of claim 1, wherein the mold feature has a concave portion.

3. The mold of claim 1, wherein the mold feature has a convex portion.

4. The mold of claim 1, wherein the interface between the spacer section and the base is a first shape, and the interface between the spacer section and the mold feature is a second shape.

5. The mold of claim 4, wherein the first shape and the second shape are the same shape.

6. The mold of claim 1, wherein the interface between the spacer section and the mold feature is circular.

7. The mold of claim 1, wherein the spacer section is tapered.

8. The mold of claim 7, wherein the cross-sectional area of the spacer section to base interface is greater than the cross-sectional area of the spacer section to mold feature interface.

9. The mold of claim 1, wherein the base further comprises an alignment element.

10. An imager module comprising:

an imager die;

an imager pixel array mounted on the imager die; and

a first combination spacer lens affixed to the imager die such that a combination lens portion is optically aligned with the imager pixel array, and a combination spacer lens cavity is provided between the imager die and the lens portion of the first combination spacer lens.

11. The imager module of claim 10, wherein the sidewalls enclosing the first combination spacer lens cavity are covered with a black coating.

12. The imager module of claim 10, wherein the sidewalls and lens portion enclosing the first combination spacer lens cavity are covered with an anti-reflective coating.

13. The imager module of claim 10 wherein the top-most portion of the combination spacer lens is covered by an opaque material having an aperture corresponding to the lens portion.

14. The imager module of claim 10, wherein the lens portion of the first combination spacer lens wafer is a convex lens.

15. The imager module of claim 10, wherein the lens portion of the first combination spacer lens wafer is a concave lens.

16. The imager module of claim 10 further comprising a polymer lens mounted on the top-surface of the first combination spacer lens in optical alignment with the lens portion of the first combination spacer lens.

17. The imager module of claim 10 further comprising a second combination spacer lens affixed to the top-surface of the first combination spacer lens.

18. The imager module of claim 17, wherein at least one of the first and second combination spacer lenses has a top-surface mounted polymer lens in optical alignment with the lens portion of the first and second combination spacer lenses.

19. The imager module of claim 16, wherein the first combination spacer lens is formed from glass having a high dispersion and the top-surface mounted polymer lens is formed from a polymer having a low dispersion such that chromatic aberrations are minimized.

20. A method of forming a combination spacer lens wafer, the method comprising:

joining a wafer blank with a form mold, the form mold comprising a base, a mold feature, and a spacer section connecting the base and the mold feature, such that the base, mold feature, and spacer section are received by the wafer blank;

curing the wafer blank sufficiently such that the wafer blank maintains the form of the base, mold feature, and spacer section upon removal of the form mold; and

removing the form mold from the wafer blank.

21. The method of claim 20 further comprising removing a portion of the top-surface material of the combination spacer lens wafer.

22. The method of claim 20 further comprising heating the wafer blank to facilitate the joining.

23. The method of claim 22, wherein heating the wafer blank occurs before the blank is joined with the form mold.

24. The method of claim 22, wherein the wafer blank is cooled after the joining.

25. The method of claim 20, wherein the form mold is formed to comprise at least one alignment element and the wafer blank receives the at least one alignment element during the joining.

26. The method of claim 20, wherein the mold feature is formed to be convex.

27. The method of claim 20, wherein the mold feature is formed to be concave.

28. The method of claim 20 further comprising applying a black coating to the sidewalls enclosing a combination spacer lens cavity left by removal of the form mold.

29. The method of claim 20 further comprising applying an anti-reflective coating to the side-walls and lens enclosing a combination spacer lens cavity left by removal of the form mold.

30. The method of claim 20, wherein the wafer blank is an ultraviolet-curable polymer and the curing is conducted by an ultraviolet-radiation source.

31. The method of claim 20, wherein the wafer blank is made of glass.

32. The method of claim 20 further comprising forming a top-surface mounted polymer lens on the combination spacer lens wafer.

33. The method of claim 32, wherein the wafer blank is made of glass having a high dispersion and the top-surface mounted polymer lens is formed from a polymer having a low dispersion such that chromatic aberrations are minimized.

34. A method of forming an imager module, the method comprising:

affixing an imager wafer comprising a die containing a pixel array to a first combination spacer lens wafer, the first combination spacer lens wafer comprising;

a combination lens portion, and

a combination spacer portion sized to place the combination lens portion an appropriate distance from the pixel array, the combination spacer portion being affixed to the die.

35. The method of claim 34 wherein the imager wafer comprises a plurality of pixel arrays and the first combination spacer wafer comprises a plurality of combination spacer lenses such that the method comprises forming a plurality of imager modules as part of a wafer assembly.

36. The method of claim 34 further comprising covering the sidewalls of the first combination spacer portion that are closest to the imager array with a black coating.

37. The method of claim 34 further comprising covering the sidewalls of the first combination spacer portion that are closest to the imager array with an anti-reflective coating, and covering the first combination lens portion closest to the imager array with an anti-reflective coating.

38. The method of claim 34 further comprising forming the combination lens portion to be convex.

39. The method of claim 34 further comprising forming the combination lens portion to be concave.

40. The method of claim 34 further comprising forming a polymer lens mounted on the top-surface of the first combination spacer lens wafer.

41. The method of claim 40 wherein the polymer lens is convex.

42. The method of claim 40 wherein the polymer lens is concave.

43. The method of claim 34 further comprising affixing a second combination spacer lens wafer to the top-surface of the first combination spacer lens wafer.

44. The method of claim 43 further comprising forming a polymer lens mounted on the top-surface of the first or second combination spacer lens wafer.