Method of separating light emitting devices formed on a substrate wafer
View Patent ↗A method according to embodiments of the invention includes providing a light emitting semiconductor structure grown on a substrate. The substrate has a front side and a back side opposite the front side. Notches are formed in the substrate. The notches extend from the front side of the substrate into the substrate. After forming notches in the substrate, the back side of the substrate is thinned to expose the notches.
1. A method comprising:
at least partially forming a light emitting semiconductor structure on a growth substrate, the light emitting semiconductor structure comprising a light emitting layer disposed between an n-type region and a p-type region, the growth substrate comprising a front side and a back side opposite the front side, the light emitting semiconductor structure being grown on the front side;
after at least partially forming the semiconductor structure on the growth substrate, forming a plurality of openings in the light emitting semiconductor structure that expose portions of the front side of the substrate, and forming notches in portions of the front side of the growth substrate that are exposed in the openings, each of the notches extending from the front side of the growth substrate into the growth substrate, each of the notches having respective sides that are inclined towards one another and meet at a bottom of the notch;
after forming the notches in the growth substrate, completing a plurality of LEDs on the growth substrates by processing the light emitting semiconductor structure on the growth substrate; and
after completing the LEDs on the growth substrate, thinning the back side of the growth substrate to expose the notches and separate the completed LEDs.
2. The method of claim 1 , wherein the notches are formed using at least one of dry etching and wet etching.
3. The method of claim 1 , wherein forming notches in the growth substrate comprises sawing or laser scribing the notches in the growth substrate.
4. The method of claim 1 , wherein the growth substrate is sapphire.
5. The method of claim 1 , wherein, after thinning the back side of the growth substrate, a portion of the growth substrate remains attached to each of the completed LEDs.
6. A method comprising:
at least partially forming a light emitting semiconductor structure on a growth substrate, the light emitting semiconductor structure comprising a light emitting layer disposed between an n-type region and a p-type region, the growth substrate comprising a front side and a back side opposite the front side, the light emitting semiconductor structure being grown on the front side;
after at least partially forming the semiconductor structure on the growth substrate, forming a plurality of openings in the light emitting semiconductor structure that expose portions of the front side of the substrate, and forming notches in portions of the front side of the growth substrate that are exposed in the openings, each of the notches extending from the front side of the growth substrate into the growth substrate, each of the notches having a U-shape;
after forming the notches in the growth substrate, completing a plurality of LEDs on the growth substrates by processing the light emitting semiconductor structure on the growth substrate; and
after completing the LEDs on the growth substrate, thinning the back side of the growth substrate to expose the notches and separate the completed LEDs.
7. The method of claim 6 , wherein the notches are formed using at least one of dry etching and wet etching.
8. The method of claim 6 , wherein forming notches in the growth substrate comprises sawing or laser scribing the notches in the growth substrate.
9. The method of claim 6 , wherein the growth substrate is sapphire.
10. The method of claim 6 , wherein, after thinning the back side of the growth substrate, a portion of the growth substrate remains attached to each of the completed LEDs.