Lumileds LLC

Koninklijke Philips Corporation N.v.

Philips Lumileds Lighting Company LLC

Frank Lili Wei

Frederic Stephane Diana

Daniel Alexander Steigerwald

Qingwei Mo

Serge Laurent Rudaz

Kwong-Hin Henry Choy

Rao S Peddada

Henry Kwong-Hin Choy

Satyanarayana Rao Peddada

Serge I Rudaz

In embodiments of the invention, a passivation layer is disposed over a side of a semiconductor structure including a light emitting layer disposed between an n-type region and a p-type region. A material configured to adhere to an underfill is disposed over an etched surface of the semiconductor structure.

Passivation for a semiconductor light emitting device

A method of separating a wafer including rows of light emitting devices is described. Dicing streets are provided on the wafer such that a respective one of the dicing streets is provided between each of the rows of light emitting devices on the wafer. The wafer is broken along a first one of the dicing streets to separate a first portion of the wafer from a remaining portion of the wafer. The first portion of the wafer includes more than one of the rows of light emitting devices. The first portion of the wafer is broken along a second one of the dicing streets to separate a second portion of the wafer from the first portion of the wafer.

Separating a wafer of light emitting devices

A two-stage singulation process is used in the fabrication of phosphor coated light emitting elements. Prior to the application of the phosphor coating, the individual light emitting elements are singulated using a laser dicing process; after application of the phosphor coating, the phosphor coated light emitting elements are singulated using a mechanical dicing process. Before laser dicing of the light emitting elements, the wafer is positioned on a piece of dicing- or die-attach-tape held by a frame; after laser dicing, the tape is stretched to provide space between the individual light emitting elements that allows for the wider kerf width of the subsequent mechanical dicing after application of the phosphor coating.

Singulation of light emitting devices before and after application of phosphor

Some embodiments include a III-nitride light emitting device with a light emitting layer disposed between an n-type region and a p-type region. A glass layer is connected to the III-nitride light emitting device. A wavelength converting layer is disposed between the III-nitride light emitting device and the glass layer. The glass layer is narrower than the III-nitride light emitting device.

Dicing a wafer of light emitting devices

A two-stage singulation process is used in the fabrication of phosphor coated light emitting elements. Prior to the application of the phosphor coating, the individual light emitting elements are singulated using a laser dicing process (); after application of the phosphor coating (), the phosphor coated light emitting elements are singulated using a mechanical dicing process (). Before laser dicing of the light emitting elements, the wafer is positioned on a piece of dicing- or die-attach-tape held by a frame; after laser dicing, the tape is stretched () to provide space between the individual light emitting elements that allows for the wider kerf width of the subsequent mechanical dicing () after application of the phosphor coating ().

Singulaton of light emitting devices before and after application of phosphor

LED dies are partially singulated while on an unthinned depth growth substrate. Slots are made through the streets separating the LED dies, but not through the growth substrate, leaving the now separated LED dies on the growth substrate. A secondary support is attached to the LED dies on the opposite surface from the growth substrate, and the growth substrate is thinned or removed, leaving the LED dies on the secondary support. Because the LED dies are separated while on the unthinned growth substrate, the likelihood of distortion before slicing is virtually eliminated, and the width of the streets between the LED dies may be correspondingly reduced.

LED thin-film device partial singulation prior to substrate thinning or removal

Embodiments of the invention are directed to a method of separating a wafer of light emitting devices. The light emitting devices are disposed in rows. The method includes dividing the wafer into a plurality of regions. Each region comprises a plurality of rows of light emitting devices and a first region is wider than a second region. For each region, the method includes determining a position of first and second dicing streets. The dicing streets are located between the rows of light emitting devices. The method includes determining, using the position of the first and second dicing streets, positions of a plurality of dicing streets disposed between the first and second dicing streets. The method includes cutting the wafer along streets.

Embodiments of the invention are directed to a method of separating a wafer of light emitting devices. The method includes scribing a first groove on a dicing street on the wafer and checking the alignment of the wafer using a location of the first groove relative to a feature on the wafer. After checking the alignment, a second groove is scribed on the dicing street.

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San Francisco, CA, United States of America

Frank Lili Wei