Singulation method and resulting device of thick gallium and nitrogen containing substrates
View Patent ↗A method for singulation of thick GaN wafers (e.g., 300-400 um) through the use of a double-side laser-scribe process. In a preferred embodiment, the patterned GaN substrate is processed using a laser-scribe on each side of the substrate to form scribe lines. The scribe lines are aligned to each other. In a preferred embodiment, the substrate has not been subjected to a thinning or polishing process for reducing its thickness.
1. A method for separating individual die from a gallium and nitrogen containing substrate having a plurality of optical devices arranged in an array, the substrate member having a front side and a back side, the method comprising:
aligning a scribe device to scribe at least a street region on a portion of the front side between a first optical device and a second optical device;
forming a first scribe line on the street region between the first optical device and the second optical device;
forming a second scribe line on a backside portion of the substrate member and overlying the first scribe line while maintaining a thickness of the substrate member between the first scribe line and the second scribe line; and
applying energy to a portion of the substrate member to separate the first optical device from the second optical device.
2. The method of claim 1 wherein the energy comprises a mechanical force.
3. The method of claim 1 wherein the substrate member has an initial thickness, the first scribe line has a first depth of about 20 to 25% of the initial thickness; and the second scribe line has a second depth of about 20 to 25% of the initial thickness.
4. The method of claim 1 wherein the first optical device has a first length, a first width, and an initial thickness greater than one of the first width or the first length.
5. The method of claim 4 wherein the initial thickness is greater than each of the first width or the first length.
6. The method of claim 1 wherein the initial thickness is from about 100 microns to about 500 microns.
7. The method of claim 1 wherein each of the optical devices includes a roughened edge surface.
8. The method of claim 1 wherein the scribe device is selected from a diamond scribe, a laser scribe, saw, chemical scribe, or dry etch scribe.
9. The method of claim 1 wherein the first scribe region is patterned.
10. The method of claim 1 wherein the first scribe region is continuous.
11. The method of claim 1 wherein the second scribe region is patterned.
12. The method of claim 1 wherein the second scribe region is continuous.
13. The method of claim 1 wherein the first scribe region and the second scribe region are offset.
14. The method of claim 1 wherein the first scribe is provided in a region overlying the second scribe.
15. A method as in claim 1 wherein the optical devices comprise light emitting diodes and the individual die comprises a single light emitting diode.