Apparatus and methods for packaging electronic devices for optical testing

• US 20060208753A1
• Filed: 03/21/2005
• Published: 09/21/2006
• Est. Priority Date: 03/21/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Stellari, Franco, Song, Peilin, Tosi, Alberto
• Granted Patent: US 7,635,904 B2
• Time in Patent Office: Days
• US Class Current: 324/756.20
• CPC Class Codes: G01R 1/0408 Test fixtures or contact fields; Connectors or connecting adaptors; Test clips; Test sockets G01R1/067 takes precedence; mass production testing systems G01R31/59; testing of connections G01R31/66; for testing printed circuit boards G01R31/2808
• CPC Class Codes: G01R 31/311 of integrated circuits G01R31/31728 takes precedence
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 25/16 the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits
• CPC Class Codes: H01L 2924/00011 Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/3011 Impedance

Abstract

Apparatus and methods are provided for packaging IC (integrated circuit) chips to enable both optical access to the back side of an IC chip and electrical access to the front side of the IC chip.

Claims

1. An apparatus for packaging electronic devices, comprising:

a mounting plate having a first surface and a second surface; and

an IC (integrated circuit) chip having a front surface and a back surface, wherein the back surface of the chip is mounted to the first surface of the mounting plate;

wherein at least a portion of the mounting plate adjacent the back surface of the IC chip is transparent to one or more wavelengths of light to allow photons to pass through the mounting plate between the first and second surfaces.

2. The apparatus of claim 1, wherein said portion of the mounting plate is transparent to photons emitted from the IC chip.

3. The apparatus of claim 1, wherein said portion of the mounting plate is transparent to photons emitted by a laser that is used to irradiate the IC chip.

4. The apparatus of claim 1, further comprising a package body, wherein the mounting plate is attached to the package body, and wherein the package body comprises wires and connectors to provide an electrical interface to the IC chip.

5. The apparatus of claim 4, wherein the package body comprises a first surface, a second surface and an aperture region formed between the first and second surfaces of the package body, and wherein the mounting plate is attached to the first surface of the package body such that the IC chip is aligned and inserted into the aperture.

6. The apparatus of claim 5, further comprising wire bonds connected to bond pads on the front surface of the IC chip and to wires or bond pads formed on the second surface of the package body.

7. The apparatus of claim 5, further comprising one or more off-chip electrical components mounted on the first surface, second surface or first and second surfaces of the package body.

8. The apparatus of claim 1, wherein the package body is formed using a printed circuit board.

9. The apparatus of claim 1, further comprising an index matching material disposed between the mounting plate and the back surface of the IC chip.

10. The apparatus of claim 9, wherein the index matching material comprises bond material that is used to bond the back surface of the IC chip to the mounting plate.

11. The apparatus of claim 1, wherein the mounting plate comprises a material that is doped with another material to match an index of refraction of the mounting plate to an index of refraction of substrate material of the IC chip.

12. The apparatus of claim 1, wherein the mounting plate is formed of silicon.

13. The apparatus of claim 1, wherein the mounting plate is formed of glass.

14. The apparatus of claim 1, wherein the mounting plate is formed of quartz.

15. The apparatus of claim 1, wherein the mounting plate is formed of diamond.

16. A method for constructing an apparatus for packaging an IC (integrated circuit) chip for optical testing, the method comprising the steps of:

forming a package body comprising electrical connectors and wiring;

forming a mounting plate having a first surface and a second surface, wherein the mounting plate is adapted to have an IC chip mounted thereto, and wherein the mounting plate is transparent to one or more wavelengths of light to allow photons to pass through the mounting plate between the first and second surfaces;

attaching the mounting plate to the package body in a structural orientation that allows a front surface of an IC chip mounted to the mounting plate to be electrically accessible and a back surface of the IC chip to be optically accessible.

17. The method of claim 16, further comprising mounting a back surface of an IC chip to the first surface of the mounting plate.

18. The method of claim 17, wherein mounting the IC chip to the mounting plate is performed prior to attaching the mounting plate to the package body.

19. The method of claim 17, wherein mounting the IC chip to the mounting plate is performed after attaching the mounting plate to the package body.

20. The method of claim 17, wherein mounting comprises using a bonding material to bond the IC chip to the mounting plate such that substantially no bonding material exists between the back surface of the IC chip and the first surface of the mounting plate.

21. The method of claim 17, further comprising disposing an index matching material between the back surface of the IC chip and the first surface of the mounting plate, wherein the index matching material comprises an index of refraction which has a value between an index of refraction of material of mounting plate and an index of refraction of substrate material of the IC chip.

22. The method of claim 21, wherein the index matching material is bonding material that is used to bond mount the IC chip to the mounting plate.

23. The method of claim 16, wherein forming the mounting plate comprises doping mounting plate material with another material to match an index of refraction of the mounting plate to an index of refraction of substrate material of said IC chip to be mounted to the mounting plate.

24. The method of claim 17, further comprising forming wire bond connections between bond pads on a front surface of the IC chip and bond pads or wires on the package body.

25. The method of claim 16, further comprising attaching off-chip electronic components to the package body.

26. The method of claim 16, wherein forming a package body comprises forming an aperture region between a first and second surface of the package body, and wherein attaching the mounting plate to the package body comprises aligning the mounting plate to the aperture region and bonding a peripheral region of the first surface of the mounting plate to a peripheral region of the first surface of the package body surrounding the aperture region.

27. The method of claim 17, further comprising thinning a substrate of the IC chip before mounting the IC chip to the mounting plate.

28. A method for optically testing an IC (integrated circuit) chip, comprising the steps of:

mounting an IC chip to a first surface of a mounting plate of a chip packaging apparatus, wherein the mounting plate is transparent to one or more wavelengths of light to provide optical access to a back side of the IC chip; and

forming electrical connections between the IC chip and the packaging apparatus to provide electrical access to a front side of the IC chip; and

performing optical testing of the IC chip through optical access from the back side of the IC chip.

29. The method of claim 28, wherein performing optical testing of the IC chip comprises:

placing a photon collecting device adjacent a second surface of the mounting plate, opposite the first surface of the mounting plate, to collect photons emitted from the back side of the IC chip and passing through the mounting plate from the first surface to the second surface.

30. The method of claim 28, wherein performing optical testing of the IC chip comprises:

placing a photon emitting device adjacent a second surface of the mounting plate, opposite the first surface of the mounting plate;

emitting photons toward the back side of the IC chip through the second surface and first surface of the mounting plate; and

analyzing an electrical response of the IC chip based on electrical signals measured on one or more of the electrical connections to the front side of the IC chip.

31. An apparatus for packaging an IC (integrated circuit) chip, the apparatus comprising means for mounting a wire bond type IC chip on the apparatus to enable both optical access to a back side of the wire bond type IC chip and electrical access to a front side of the wire bond type IC chip.