HIGH-TEMPERATURE, SPIN-ON, BONDING COMPOSITIONS FOR TEMPORARY WAFER BONDING USING SLIDING APPROACH

• US 20100206479A1
• Filed: 04/29/2010
• Published: 08/19/2010
• Est. Priority Date: 10/06/2006
• Status: Active Grant

• Current Assignee: Brewer Science Inc.
• Original Assignee: Brewer Science Inc.
• Inventors: Li, Chenghong, Pillalamarri, Sunil K.
• Granted Patent: US 9,728,439 B2
• Time in Patent Office: Days
• US Class Current: 156/344
• CPC Class Codes: B29B 17/02 Separating plastics from other materials
• CPC Class Codes: B32B 38/10 Removing layers, or parts of layers, mechanically or chemically
• CPC Class Codes: B32B 43/006 Delaminating
• CPC Class Codes: C09J 2301/502 process for debonding adherents
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 2221/68327 used during dicing or grinding
• CPC Class Codes: H01L 2221/6834 used to protect an active side of a device or wafer
• CPC Class Codes: H01L 2924/30105 Capacitance
• CPC Class Codes: Y10T 156/11 Methods of delaminating, per se; i.e. , separating at bonding face
• CPC Class Codes: Y10T 156/1153 Temperature change for delamination [e.g., heating during delaminating, etc.]
• CPC Class Codes: Y10T 156/1168 Gripping and pulling work apart during delaminating
• CPC Class Codes: Y10T 156/1189 with shearing during delaminating
• CPC Class Codes: Y10T 156/19 Delaminating means
• CPC Class Codes: Y10T 156/1972 Shearing delaminating means
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

New compositions and methods of using those compositions as bonding compositions are provided. The compositions comprise a polymer dispersed or dissolved in a solvent system, and can be used to bond an active wafer to a carrier wafer or substrate to assist in protecting the active wafer and its active sites during subsequent processing and handling. The compositions form bonding layers that are chemically and thermally resistant, but that can also be softened to allow the wafers to slide apart at the appropriate stage in the fabrication process.

Claims

1. A wafer bonding method comprising:

providing a stack comprising first and second substrates bonded together via a bonding layer formed from a bonding composition comprising a polymer dissolved or dispersed in a solvent system;

subjecting said stack to heat so as to soften said bonding layer; and

applying a force to at least one of said first and second substrates while causing the other of said first and second substrates to resist said force, said force being applied in a sufficient amount so as to separate said first and second substrates.

2. The method of claim 1, said stack having an axis that passes through both the first and second substrates, said force being applied in a generally transverse direction relative to said axis.

3. The method of claim 1, said applying a force comprising lifting the at least one first and second substrate in a direction generally away from the other of said first and second substrates.

4. The method of claim 1, further comprising subjecting said stack to a temperature of at least about 190°

C.

5. The method of claim 1, further comprising thinning one of said substrates prior to subjecting said stack to heat.

6. The method of claim 1, further comprising subjecting said stack to a process selected from the group consisting of backgrinding, metallizing, patterning, and combinations thereof prior to subjecting said stack to heat.

7. The method of claim 1, wherein said polymer is at least about 95% soluble in nonpolar solvents.

8. The method of claim 1, wherein said composition further comprises an ingredient selected from the group consisting of tackifiers, adhesion promoting agents, antioxidants, surfactants, and mixtures of the foregoing.

9. The method of claim 1, wherein said first substrate has a first surface and a second surface remote from said first surface and comprising at least one active site and plurality of topographical features, and said bonding layer is bonded to said second surface.

10. The method of claim 9, wherein said second substrate comprises a bonding surface that is bonded to said bonding layer.

11. The method of claim 10, wherein:

said topographical features present respective end surfaces remote from the first surface of said first substrate, and at least one of the end surfaces is further from the first surface of the first substrate than the other of said end surfaces, said further end surface defining a plane that is substantially parallel to said first surface; and

the distance from said plane to the bonding surface on said second substrate varying by less than about 10% across said plane and second substrate bonding surface.

12. The method of claim 1, wherein said first substrate:

has a first surface and a second surface remote from said first surface;

comprises at least one active site and plurality of topographical features on said second surface; and

is selected from the group consisting of microelectromechanical system devices, display devices, flexible substrates, compound semiconductors, low k dielectric layers, dielectric layers, ion implant layers, and substrates comprising silicon, aluminum, tungsten, tungsten silicide, gallium arsenide, germanium, tantalum, tantalum nitrite, SiGe, and mixtures of the foregoing.

13. The method of claim 1, wherein said second substrate comprises a carrier wafer comprising a material selected from the group consisting of sapphire, ceramic, glass, quartz, aluminum, silver, and silicon.

14. The method of claim 1, wherein said providing a stack comprises:

applying the bonding composition to one of the first and second substrates to form a bonding composition-coated substrate and a bonding composition-free substrate; and

contacting the bonding composition-free substrate with the bonding composition-coated substrate so as to bond the substrates together.

15. The method of claim 14, wherein said applying comprises spincoating the bonding composition onto one of the first and second substrates.

16. An article comprising:

a first substrate having a back surface and an active surface, said active surface comprising at least one active site and a plurality of topographical features;

a second substrate having a bonding surface; and

a thermoplastic bonding layer bonded to said active surface and to said bonding surface, wherein;

said topographical features present respective end surfaces remote from the back surface of said first substrate, and at least one of the end surfaces is further from the back surface of the first substrate than the other of said end surfaces, said further end surface defining a plane that is substantially parallel to said first surface; and

the distance from said plane to the bonding surface on said second substrate varying by less than about 5% along said plane and second substrate bonding surface.

17. The article of claim 16, said bonding layer:

having a thickness defined as the distance from the active surface to the bonding surface; and

comprising the same composition across said thickness.

18. The article of claim 16, wherein said first substrate is selected from the group consisting of microelectromechanical system devices, display devices, flexible substrates, compound semiconductors, low k dielectric layers, dielectric layers, ion implant layers, and substrates comprising silicon, aluminum, tungsten, tungsten silicide, gallium arsenide, germanium, tantalum, tantalum nitrite, SiGe, and mixtures of the foregoing.

19. The article of claim 16, wherein said second substrate comprises a material selected from the group consisting of sapphire, ceramic, glass, quartz, aluminum, silver, and silicon.

20. The article of claim 16, wherein said bonding layer has a softening temperature of at least about 190°

C.