Method of stress induced cleaving of semiconductor devices
View Patent ↗A method of dicing semiconductor devices includes depositing a continuous first layer over the substrate, such that the first layer imparts a compressive stress to the substrate, and etching grooves in the first layer to increase local stress at the grooves compared to stress at the remainder of the first layer located over the substrate. The method also includes generating a pattern of defects in the substrate with a laser beam, such that a location of the defects in the pattern of defects substantially corresponds to a location of at least some of the grooves in the in the first layer, and applying pressure to the substrate to dice the substrate along the grooves.
1. A method of dicing semiconductor devices, comprising:
depositing a continuous first layer over a substrate, wherein the first layer imparts a compressive stress to the substrate;
etching grooves in the first layer to increase local stress at the grooves compared to stress at the remainder of the first layer located over the substrate;
generating a pattern of defects in the substrate with a laser beam, wherein a location of the defects in the pattern of defects substantially corresponds to a location of at least some of the grooves in the in the first layer;
applying pressure to the substrate to dice the substrate along the grooves; and
further comprising forming light emitting diodes (LEDs) over the first layer prior to the step of etching grooves;
wherein:
the substrate comprises sapphire and the first layer comprises a III-nitride semiconductor layer;
the first layer comprises a GaN buffer layer; and
the step of etching grooves comprises etching street grooves in inactive regions through the LEDs and through the first layer to expose the substrate and to define a pattern of individual LED dies on a first side of the substrate.
2. The method of claim 1 , wherein the laser beam is provided onto a second side of the substrate opposite the first side of the substrate.
3. The method of claim 1 , wherein the laser beam is provided onto the first side of the substrate through the grooves in the first layer.
4. The method of claim 1 , wherein dicing the substrate along the grooves comprises dicing the substrate to generate a plurality of LED dies, and wherein the street grooves and the pattern of defects mimic a pattern of individual LED dies.
5. The method of claim 1 , wherein the pattern of defects comprises a region of defects located less than 10 microns below a surface of the substrate.
6. The method of claim 1 , wherein each of the LED dies has more than four sides.
7. The method of claim 1 , wherein the step of applying pressure to the substrate to dice the substrate along the grooves comprises passing one or more rollers over the substrate.
8. The method of claim 7 , further comprising mounting the substrate on a tape prior to passing one or more rollers over the substrate.
9. The method of claim 7 , wherein the substrate is cleaved along a non-preferred crystalline cleaving orientation during the step of applying pressure to the substrate to dice the substrate along the grooves.