Method of manufacturing transferable elements incorporating radiation enabled lift off for allowing transfer from host substrate

• US 8,334,152 B2
• Filed: 12/14/2010
• Issued: 12/18/2012
• Est. Priority Date: 12/18/2009
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Cooledge Lighting Inc.
• Inventors: Speier, Ingo
• Primary Examiner(s): Lee, Hsien Ming
• Assistant Examiner(s): Swanson, Walter H
• Application Number:
  US12/968,275
• Publication Number:
  US 20110151602A1
• Time in Patent Office: 735 Days
• Field of Search: 257/E21.06, 257/E21.061, 257/E21.499, 257/E21.502, 257/E33.023, 257/E33.026, 257/E33.028, 257/E33.031, 257/E33.035, 257/E33.055, 257/E33.059, 257/E33.067, 438/22, 438/25, 438/26, 438/27, 438/28, 438/31, 438/36, 438/107, 438/126, 438/127, 438/458, 438/462, 438/463, 438/708, 216/65, 264/2.7, 264/104
• US Class Current: 438/26
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 21/6836 Wafer tapes, e.g. grinding or dicing support tapes adhesive tapes in general C09J7/20
• CPC Class Codes: H01L 2221/68322 Auxiliary support including means facilitating the selective separation of some of a plurality of devices from the auxiliary support
• CPC Class Codes: H01L 2221/68354 used to support diced chips prior to mounting
• 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 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination

Abstract

Semiconductor material is formed on a host substrate of a material exhibiting optical transparency with an intervening radiation lift off layer. A transfer device, intermediate substrate or target substrate is brought into adhesive contact with the semiconductor material and the radiation lift off layer is irradiated to weaken it, allowing the semiconductor material to be transferred off the host substrate. Electronic devices may be formed in the semiconductor layer while it is attached to the host substrate or the intermediate substrate.

Claims

1. A method of manufacturing a transferable element, comprising the steps of:

providing a host substrate of a material exhibiting optical transparency;

forming an epitaxial layer on said host substrate including a layer allowing for radiation lift off;

defining one or more semiconductor dies in said epitaxial layer;

adhering a target substrate to one or more of said semiconductor dies, the adhering step comprising (i) bringing the target substrate into close proximity with the one or more semiconductor dies, (ii) creating contact between the target substrate and selected ones of the semiconductor dies, and (iii) bonding the selected semiconductor dies to the target substrate;

irradiating said radiation lift off layer to weaken the layer; and

moving said host substrate and said target substrate apart, thereby transferring said one or more semiconductor dies from said host substrate to said target substrate,

wherein bonding the selected semiconductor dies occurs concurrently with the irradiating of the radiation lift off layer.

2. The method of claim 1 wherein said bonding is by one of melting and solidifying solder or curing adhesive between the selected semiconductor dies and the target substrate.

3. The method of claim 1 wherein mesas are provided on the target substrate that receive the selected semiconductor dies.

4. A method of manufacturing a transferable element, comprising the steps of:

providing a host substrate of a material exhibiting optical transparency;

forming an epitaxial layer on said host substrate including a layer allowing for radiation lift off;

adhering an intermediate substrate to said epitaxial layer using selectively polymerized and unpolymerized adhesive;

irradiating said radiation lift off layer to weaken the layer;

removing the host substrate;

defining one or more semiconductor dies in said epitaxial layer;

removing unpolymerized adhesive;

adhering a transfer device to one or more of said semiconductor dies; and

moving said transfer device and said intermediate substrate apart, thereby transferring said one or more semiconductor dies from said intermediate substrate to said transfer device.

5. The method of claim 4 wherein said forming step includes growing a buffer layer on a host substrate followed by growing the epitaxial layer on the buffer layer.

6. The method of claim 5 wherein said forming step also includes roughening an exposed surface of the epitaxial layer.

7. The method of claim 5 wherein said adhering step includes applying a layer of polymerizable adhesive to the intermediate substrate followed by selectively polymerizing the adhesive to bond the epitaxial layer to the intermediate substrate.

8. The method of claim 7 wherein said irradiating step includes decomposing the buffer layer.

9. The method of claim 8 wherein said defining step includes applying a polymerizable photoresist layer to the epitaxial layer.

10. The method of claim 9 wherein said defining step also includes etching the photoresist layer to form the semiconductor dies.