Method and apparatus for removing a reversibly mounted device wafer from a carrier substrate

• US 8,852,391 B2
• Filed: 06/21/2010
• Issued: 10/07/2014
• Est. Priority Date: 06/21/2010
• Status: Active Grant

• Current Assignee: Brewer Science Inc.
• Original Assignee: Brewer Science Inc.
• Inventors: McCutcheon, Jeremy W., Brown, Robert D.
• Primary Examiner(s): Osele, Mark A
• Application Number:
  US12/819,680
• Publication Number:
  US 20110308739A1
• Time in Patent Office: 1,569 Days
• Field of Search: 156/714, 156/764, 156/930, 156/941, 438/455, 438/458, 292/39
• US Class Current: 156/714
• CPC Class Codes: H01L 21/187 by direct bonding
• CPC Class Codes: H01L 21/67092 Apparatus for mechanical treatment or grinding or cutting, see the relevant groups in subclasses B24B or B28D
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 21/68721 characterised by edge clamping, e.g. clamping ring
• CPC Class Codes: H01L 2221/68318 Auxiliary support including means facilitating the separation of a device or wafer from the auxiliary support
• CPC Class Codes: H01L 2221/6834 used to protect an active side of a device or wafer
• CPC Class Codes: H01L 2221/68381 Details of chemical or physical process used for separating the auxiliary support from a device or wafer
• CPC Class Codes: H01L 2221/68386 Separation by peeling
• CPC Class Codes: Y10S 156/93 Semiconductive product delaminating, e.g. delaminating emiconductive wafer from underlayer
• CPC Class Codes: Y10S 156/941 Means for delaminating semiconductive product
• CPC Class Codes: Y10T 156/1168 Gripping and pulling work apart during delaminating
• CPC Class Codes: Y10T 156/1978 Delaminating bending means
• CPC Class Codes: Y10T 156/1989 Corner edge bending delaminating means

Abstract

New demounting methods and apparatuses for separating temporarily, permanently, or semi-permanently bonded substrates and articles formed from those methods and apparatuses are provided. The methods comprise demounting a device wafer from a carrier wafer or substrate that have only been strongly bonded at their outer perimeters. The edge bonds are chemically, mechanically, acoustically, or thermally softened, dissolved, or disrupted to allow the wafers to be easily separated with very low forces and at or near room temperature at the appropriate stage in the fabrication process. A clamp for facilitating separation of the bonded substrates is also provided.

Claims

1. A temporary bonding method comprising:

providing a stack comprising;

a first substrate having a back surface and a device surface, said device surface having a peripheral region and a central region;

a second substrate bonded to said first substrate, said second substrate having a carrier surface, a backside surface, and an outermost edge defining the periphery of the second substrate, said carrier surface having a peripheral region and a central region and comprising a surface modification, said carrier surface comprising surface-modified portions and non-modified portions, wherein said surface-modified portions have a low bonding surface; and

a uniform bonding layer between said first substrate and said second substrate, said bonding layer being formed from a polymeric adhesive; and

separating said first and second substrate using a peeling motion by applying a force to a portion of the periphery of said second substrate causing said second substrate to bend at an angle away from the stack, thereby separating said first substrate and second substrate.

2. The method of claim 1, said bonding layer being bonded to said device surface and to said peripheral region of said carrier surface, wherein said bonding layer and said central region of said carrier surface comprise a low bonding interface therebetween.

3. The method of claim 2, wherein said low bonding interface comprises surface modification of said central region of said carrier surface.

4. The method of claim 1, further comprising mechanically or chemically disrupting said bonding layer adjacent said peripheral regions to remove at least a portion of said bonding layer prior to said separating.

5. The method of claim 1, said bonding layer being bonded to said device surface and to non-modified portions of said carrier surface, wherein said bonding layer and said surface-modified portions of said carrier surface comprise a low bonding interface therebetween.

6. The method of claim 1, wherein said device surface comprises an array of devices selected from the group consisting of integrated circuits;

MEMS;

microsensors;

power semiconductors;

light-emitting diodes;

photonic circuits;

interposers;

embedded passive devices; and

microdevices fabricated on or from silicon, silicon-germanium, gallium arsenide, and gallium nitride.

7. The method of claim 1, said device surface comprising at least one structure selected from the group consisting of:

solder bumps;

metal posts;

metal pillars; and

structures formed from a material selected from the group consisting of silicon, polysilicon, silicon dioxide, silicon (oxy)nitride, metal, low k dielectrics, polymer dielectrics, metal nitrides, and metal silicides.

8. The method of claim 1, wherein said second substrate comprises a material selected from the group consisting of silicon, sapphire, quartz, metal, glass, and ceramics.

9. The method of claim 1, further comprising subjecting said stack to processing selected from the group consisting of back-grinding, chemical-mechanical polishing, etching, metal and dielectric deposition, patterning, passivation, annealing, and combinations thereof, prior to separating said first and second substrates.

10. The method of claim 1, wherein said separating is carried out using a ring clamp having a planar body with a substantially circular shape defining the periphery of said ring clamp and a central opening, said ring clamp being secured about the periphery of the second substrate, and wherein said force is applied to only a portion of the periphery of said ring clamp thereby lifting the corresponding portion of the periphery of the second substrate away from the stack in said peeling motion.

11. The method of claim 10, said body comprising:

an annular interior sidewall;

an annular exterior sidewall;

a top surface extending between the interior sidewall and the exterior sidewall;

a wafer-engaging surface extending outwardly from the interior sidewall, said wafer-engaging surface terminating at a point in the body, that is spaced from the exterior sidewall; and

an inwardly extending annular ridge, which slopes inward from said point, and away from the wafer-engaging surface,

wherein said wafer-engaging surface and annular ridge cooperatively form an annular wafer-receiving groove, at least a portion of the periphery of said second substrate being received in said groove.

12. The method of claim 11, wherein said body is in the form of a split ring clamp having two free ends.

13. The method of claim 12, wherein said ring clamp is secured about the periphery of said second substrate by:

moving said free ends away from one another, thereby enlarging the central opening of said body;

placing said ring clamp about the periphery of the second substrate; and

drawing said free ends toward one another to compressively engage the second substrate, prior to said separating,

wherein the annular ridge of said ring clamp terminates in a free edge and has a sloped shoulder surface extending between the free edge of the ridge and the point where the wafer-engaging surface terminates in the body, the backside surface of said second substrate being engaged by the wafer-engaging surface of the body and the outermost edge and peripheral region of the second substrate being engaged by the shoulder and free edge of the ridge.

14. The method of claim 13, wherein said ring clamp engages at least about 1°

of the periphery of said second substrate.

15. The method of claim 1, wherein the first substrate of said stack is secured to a chuck prior to separating said substrates.

16. The method of claim 15, said first substrate being secured to said chuck via an electrostatic force, a vacuum force, magnetic force, mechanical force, physical restraint, or a layer of adhesive film between said chuck and said first substrate.

17. The method of claim 15, wherein said chuck is moved away from the second substrate during said separating.

18. The method of claim 1, wherein said separating is carried out using a flexible chuck having a periphery, said second substrate being secured to said flexible chuck, said force being applied to only a portion of the periphery of said flexible chuck thereby lifting the corresponding portion of the periphery of said second substrate away from the stack in said peeling motion.

19. The method of claim 1, wherein said separating is carried out using an adhesive film having a periphery, said second substrate being secured to said adhesive film, said force being applied to only a portion of the periphery of said adhesive film thereby lifting the corresponding portion of the periphery of the second substrate away from the stack in said peeling motion.

20. The method of claim 1, said surface-modified portions comprising a pattern.

21. The method of claim 20, wherein said pattern is selected from the group consisting of grids, lines, and shapes.

22. The method of claim 1, wherein the bonding interface between said bonding layer and said carrier surface has high adhesive strength regions and low adhesive strength regions.

23. The method of claim 1, wherein said polymeric adhesive has an adhesion strength of from about 80 psig to about 250 psig.

24. The method of claim 11, wherein said ring clamp does not contact said first substrate.

25. A temporary bonding method comprising:

providing a stack comprising;

a first substrate having a back surface and a device surface, said device surface having a peripheral region and a central region;

a second substrate bonded to said first substrate, said second substrate having a carrier surface, a backside surface, and an outermost edge defining the periphery of the second substrate, said carrier surface having a peripheral region and a central region; and

an intermediate layer comprising a uniform bonding layer between said first substrate and said second substrate, said bonding layer being formed from resins or polymers that exhibit a high adhesion strength to semiconductor materials, glass, and metals, said intermediate layer being bonded to said device surface and to said peripheral region of said carrier surface, wherein said intermediate layer and said central region of said carrier surface comprise a low bonding interface therebetween, wherein said low bonding interface comprises surface modification of said central region of said carrier surface; and

separating said first and second substrate using a peeling motion by applying a force to a portion of the periphery of said second substrate causing said second substrate to bend at an angle away from the stack, thereby separating said first substrate and second substrate.

26. The method of claim 25, wherein said resins or polymers have an adhesion strength of from about 80 psig to about 250 psig.

27. A temporary bonding method comprising:

providing a stack comprising;

a first substrate having a back surface and a device surface, said device surface having a peripheral region and a central region;

a second substrate bonded to said first substrate, said second substrate having a carrier surface, a backside surface, and an outermost edge defining the periphery of the second substrate, said carrier surface having a peripheral region and a central region and comprising a surface modification, said carrier surface comprising surface-modified portions and non-modified portions, wherein said surface-modified portions have a low bonding surface; and

separating said first and second substrate using a peeling motion by applying a force to a portion of the periphery of said second substrate causing said second substrate to bend at an angle away from the stack, thereby separating said first substrate and second substrate

wherein said separating is carried out using a ring clamp having a planar body with a substantially circular shape defining the periphery of said ring clamp and a central opening, said ring clamp being secured about the periphery of the second substrate, and wherein said force is applied to only a portion of the periphery of said ring clamp thereby lifting the corresponding portion of the periphery of the second substrate away from the stack in said peeling motion.

28. The method of claim 27, said body comprising:

an annular interior sidewall;

an annular exterior sidewall;

a top surface extending between the interior sidewall and the exterior sidewall;

a wafer-engaging surface extending outwardly from the interior sidewall, said wafer-engaging surface terminating at a point in the body that is spaced from the exterior sidewall; and

an inwardly extending annular ridge, which slopes inward from said point, and away from the wafer-engaging surface,

wherein said wafer-engaging surface and annular ridge cooperatively form an annular wafer-receiving groove, at least a portion of the periphery of said second substrate being received in said groove.

29. The method of claim 28, wherein said body is in the form of a split ring clamp having two free ends.

30. The method of claim 29, wherein said ring clamp is secured about the periphery of said second substrate by:

moving said free ends away from one another, thereby enlarging the central opening of said body;

placing said ring clamp about the periphery of the second substrate; and

drawing said free ends toward one another to compressively engage the second substrate, prior to said separating,

wherein the annular ridge of said ring clamp terminates in a free edge and has a sloped shoulder surface extending between the free edge of the ridge and the point where the wafer-engaging surface terminates in the body, the backside surface of said second substrate being engaged by the wafer-engaging surface of the body and the outermost edge and peripheral region of the second substrate being engaged by the shoulder and free edge of the ridge.

31. The method of claim 30, wherein said ring clamp engages at least about 1°

of the periphery of said second substrate.

32. The method of claim 27, wherein said ring clamp does not contact said first substrate.