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Method for Mesa separation of Spalled LEDs

IP.com Disclosure Number: IPCOM000234114D
Publication Date: 2014-Jan-13
Document File: 3 page(s) / 132K

Publishing Venue

The IP.com Prior Art Database

Abstract

A method is disclosed for mesa separation of spalled Light Emitting Diodes (LEDs). The method isolates deep mesas within large thin films using a double layer mesa mask.

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Method for Mesa separation of Spalled LEDs

Currently, there are no thin-film large area Light Emitting Diodes (LEDs). A deep

Reactive Ion Etching (RIE) is essential where conventional masks and processes fail due to extended chamber etching time. Such long RIE etching heats up the wafer and results in failure of photo resist.

A method is disclosed for mesa separation of spalled LEDs . The method isolates deep mesas within large thin films using a double layer mesa mask . The top most layer is Nickel or a similar non-etchable metal and the bottom layer is an easily etchable material relative to Nickel, such as ZnO and the like. In this configuration, Nickel can be removed later through undercutting the easily etchable layer thereby resulting in singulated mesas.

Initially, the epitaxial layer is as shown in fig. 1. The structure shown in fig. 1 also has a stressor layer, which is preferably a Nickel stressor layer.

Figure 1

In accordance with the method, a current spreading contact such as N- indium tin oxide (ITO) or N- transparent conducting oxide (TCO) is deposited on the epitaxial layer, as shown in fig. 2.

Figure 2

Subsequently, a selectively etchable layer such as, SiO2, is deposited for protection, as shown in fig. 3.

1


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Figure 3

Thereafter, a hard mask material is deposited using photolithography for RIE (for instance nickel), as shown in fig. 4.

Figure 4

Once the hard mask material is deposited, RIE is performed which results in the structure...