Bi-convex solid immersion lens

• US 6,594,086 B1
• Filed: 01/16/2002
• Issued: 07/15/2003
• Est. Priority Date: 01/16/2002
• Status: Expired due to Term

• Current Assignee: DCG Systems Incorporated (Thermo Fisher Scientific Incorporated)
• Original Assignee: Optonics, Inc. (COHU Incorporated)
• Inventors: Pakdaman, Nader, Vickers, James S.
• Primary Examiner(s): Sugarman, Scott J.
• Assistant Examiner(s): RAIZEN, DEBORAH A
• Application Number:
  US10/052,011
• Time in Patent Office: 545 Days
• Field of Search: 359/368, 359/656-661
• US Class Current: 359/656
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G02B 3/00 Simple or compound lenses
• CPC Class Codes: G02B 3/02 with non-spherical faces G02B3/10 takes precedence
• CPC Class Codes: G11B 2007/13727 Compound lenses, i.e. two or more lenses co-operating to perform a function, e.g. compound objective lens including a solid immersion lens, positive and negative lenses either bonded together or with adjustable spacing
• CPC Class Codes: G11B 7/122 Flying-type heads, e.g. analogous to Winchester type in magnetic recording
• CPC Class Codes: G11B 7/1374 Objective lenses optical objectives per se G02B9/00
• CPC Class Codes: G11B 7/1378 Separate aberration correction lenses; Cylindrical lenses to generate astigmatism; Beam expanders
• CPC Class Codes: G11B 7/1387 using the near-field effect
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device

Abstract

A bi-convex solid immersion lens is disclosed. Unlike conventional plano-convex solid immersion lenses having a flat bottom surface, the disclosed lens has a convex bottom surface. The radius of curvature of the bottom surface is smaller than that of the object to be inspected. This construction allows for a more accurate determination of the location of the inspected feature, and enhances coupling of light between the immersion lens and the inspected object. The disclosed lens is particularly useful for use in microscope for inspection of semiconductor devices and, especially flip-chip (or chip scale) packaged devices. The immersion lens can also be incorporated in a read or read/write head of optical memory media.

Claims

1. A bi-convex immersion lens, comprising:

an upper convex surface having a first radius of curvature; and

a bottom convex surface having a second radius of curvature;

wherein the second radius of curvature is larger than the first radius of curvature.

2. The bi-convex immersion lens of claim 1, wherein the second radius of curvature is a least one order of magnitude larger than that of the first radius of curvature.

3. The bi-convex immersion lens of claim 2, wherein the bottom surface passes through the radial geometrical center of the upper surface.

4. The bi-convex immersion lens of claim 2, wherein the bottom surface passes above the radial geometrical center of the upper surface.

5. The bi-convex immersion lens of claim 2, wherein the bottom surface passes below the radial geometrical center of the upper surface.

6. The bi-convex immersion lens of claim 1, wherein the bottom surface passes below the radial geometrical center of the upper surface.

7. The bi-convex immersion lens of claim 1, wherein the bottom surface passes below the radial geometrical center of the upper surface.

8. The bi-convex immersion lens of claim 1, wherein the bottom surface passes below the radial geometrical center of the upper surface.

9. The bi-convex immersion lens of claim 1, wherein said upper convex surface further comprises an anti-reflective coating.

10. The bi-convex immersion lens of claim 1, further comprising a receding surface surrounding said bottom surface.

11. The bi-convex immersion lens of claim 1, wherein said lens comprises silicon.

12. A microscope for inspecting an object, comprising:

an objective lens; and

a bi-convex immersion lens comprising an upper convex surface having a first radius of curvature and a bottom convex surface having a second radius of curvature;

wherein the second radius of curvature is large than the first radius of curvature.

13. The microscope of claim 12, wherein said immersion lens is coupled to the object.

14. The microscope of claim 12, wherein the bottom surface of said immersion lens passes through the radial geometrical center of the upper surface.

15. The microscope of claim 12, wherein the bottom surface of said immersion lens passes above the radial geometrical center of the upper surface.

16. The microscope of claim 12, wherein the bottom surface of said immersion lens passes below the radial geometrical center of the upper surface.

17. An immersion lens comprising:

an upper convex surface having a first radius of curvature;

a bottom surface a second radius of curvature and having a substantially small and defined point of contact;

wherein the second radius of curvature is larger than the first radius of curvature.

18. The immersion lens of claim 17, wherein the bottom surface further comprises a receding surface around said point of contact.

19. The immersion lens of claim 17, wherein said point of contact has a radius of curvature of at last one order of magnitude larger than that of the upper surface.