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Verfahren und Vorrichtung zur Herstellung eines Halbleiterbauelements

Manufacturing a gallium nitride-based LED, comprises depositing a semiconductor layer structure comprising a gallium nitride-based semiconductor layer on a substrate, and partially removing the layer in local areas by laser machining
 
: Moser, Rüdiger; Kunzer, Michael; Goßler, Christian; Schwarz, Ulrich

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Frontpage ()

DE 102013201298 A1: 20130128
German
Patent, Electronic Publication
Fraunhofer IAF ()

Abstract
The method comprises depositing a semiconductor layer structure on a substrate, where the structure comprises a gallium nitride (GaN)-based semiconductor layer, and partially removing the semiconductor layer in local areas by laser machining. The laser treatment is carried out by: exposing the semiconductor layer to a projection mask (4), which is illuminated with laser radiation of an ablation laser (1) such that exposure areas of the semiconductor layer is exposed through recesses in the projection mask; and occulting the GaN-based semiconductor layer shaded by the projection mask.

The method comprises depositing a semiconductor layer structure on a substrate, where the semiconductor layer structure comprises a gallium nitride (GaN)-based semiconductor layer, and partially removing the GaN-based semiconductor layer in local areas by laser machining. The laser treatment is carried out by: exposing the GaN-based semiconductor layer to a projection mask (4), which is illuminated with laser radiation of an ablation laser (1) such that exposure areas of the GaN-based semiconductor layer is exposed through recesses in the projection mask; and occulting the GaN-based semiconductor layer shaded by the projection mask. A laser fluence of the ablation laser is above an ablation threshold of the GaN-based semiconductor layer. An excimer laser is used as the ablation laser, and has a wavelength of = 351 nm and a pulse length of = 40 nanoseconds. The semiconductor layer structure comprises an active region in the exposure areas. A luminous area of a semiconductor device is effected by removing the active region in the exposure areas by mechanical separation and electrical isolation. The exposure areas of the semiconductor layer structure are completely removed. A set of semiconductor devices is formed on a wafer that is perpendicular to the laser radiation. The removing step is repeated for five times. The method further comprises displacing the wafer such that the displacement of the wafer is perpendicular to the laser radiation, and etching step. The displacing step is carried out simultaneously with the removing step. An independent claim is included for an apparatus for processing a semiconductor device.

USE: The method is useful for manufacturing a semiconductor device such as GaN-based LED (all claimed).

ADVANTAGE: The method is capable of accurately controlling the laser ablation depth thus economically and time-effectively manufacturing the semiconductor device with good quality and without damaging the semiconductor material during the laser processing.

The diagram shows a schematic view of an apparatus for processing a semiconductor device. 1 : Ablation laser 3 : Beam homogenizer 4 : Projection mask 5 : Focusing lens 7 : Holder

: http://publica.fraunhofer.de/documents/N-311172.html