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AssigneeEmcore Corporation
InventorsMichael G. Brown, Ivan Eliashevich, Robert F. Karlicek Jr., James E. Nering, Mark Gottfried
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Abstract of Disclosure A method for separating a semiconductor wafer into several thousand devices or die by laser ablation. Semiconductor wafers are initially pre-processed to create multiple devices, such as blue LEDs, on the wafers. The wafers are then mounted with tape coated with a generally high level adhesive. The mounted wafer is then placed on a vacuum chuck (which is itself positioned on a computer controlled positioning table) to hold it in place during the cutting process. The cutting surface is then covered with a protective layer to prevent contamination from the effluent resulting from the actual cutting process. A laser beam is generated and passed through optical elements and masks to create a pattern, such as a line or multiple lines. The patterned laser projection is directed at the wafer at a substantially normal angle and applied to the wafer until at least a partial cut is achieved through it. A mechanical separation process completes the separation when only a partial cut is achieved by the patterned laser projection. The die are then transferred to a grip ring for further processing.
Please cancel claims 1-34.
35.A method for scribing a semiconductor wafer, said method comprising the steps of:
37.The method of claim 35, wherein said sapphire substrate has a bandgap value greater than an energy value for the laser projection.
38.The method of claim 35, wherein said sapphire substrate has a C-plane orientation.
39.The method of claim 35, wherein said patterned laser projection is one selected from the group consisting of long lines, multiple lines, multiple parallel lines and grids.
40.The method of claim 35, wherein said surface is a back/substrate surface of said semiconductor wafer.
41.The method of claim 35, wherein said surface is a front/epitaxial surface of said semiconductor wafer.
42.The method of claim 35, wherein a kerf width is less than 10 micrometers for minimizing wastage of said semiconductor wafer.
43.The method of claim 35, wherein a kerf width is less than 20 micrometers for minimizing wastage of said semiconductor wafer.
44.The method of claim 35, wherein a kerf width is less than 100 micrometers for minimizing wastage of said semiconductor wafer.
45.The method of claim 35, wherein a kerf width is less than 20 micrometers and no more than 28 micrometers for minimizing wastage of the semiconductor wafer.
46.The method of claim 35, wherein said at least one partial cut is less than 3.5 mils in depth.
47.The method of claim 35, wherein said step of directing includes the step of generating laser light emissions capable of cutting the sapphire substrate via laser ablation.
48.The method of claim 35, wherein said device layer comprises gallium nitride.
49.The method of claim 35, wherein said device layer comprises gallium arsenide.
50.The method of claim 35, wherein said device layer comprises aluminum nitride.
51.The method of claim 35, wherein said device layer comprises indium nitride.
52.The method of claim 35, wherein said device layer comprises silicon.
53.The method of claim 35, wherein said device layer comprises III-V material.
54.A method for preparing a semiconductor wafer comprising the steps of:
55.The method of claim 54, wherein said device layer comprises gallium nitride.
56.The method of claim 54, wherein said device layer comprises gallium arsenide.
57.The method of claim 54, wherein said device layer comprises aluminum nitride.
58.The method of claim 54, wherein said device layer comprises indium nitride.
59.The method of claim 54, wherein said device layer comprises silicon.
60.The method of claim 54, wherein said device layer comprises III-V material.
Dependencies are inferred from the claim text.