Self-alignment process for micro light emitting diode using back-side exposure

US10741717B1 · kind B1 · utility

Assignee

• Facebook Technologies, LLC · US

Inventors

• Celine Claire Oyer · Cork, IE
• David Massoubre · Cork, IE
• Tilman Zehender · Cork, IE

Key dates

• Filing date: Mar 18, 2019
• Grant date: Aug 11, 2020
• Expiry date: Mar 18, 2039

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10H20/825

Abstract

Embodiments relate to a micro light-emitting-diode (μLED) fabricated using a self-aligned process. To fabricate the μLED, a metal layer is deposited on a p-type semiconductor. The p-type semiconductor is on an n-type semiconductor and the n-type semiconductor is on a top side of a substrate. The metal layer is patterned to define a p-metal. The p-type semiconductor is etched using the p-metal as an etch mask. Similarly, the n-type semiconductor is etched using the p-metal and the p-type semiconductor as an etch mask. A negative photoresist layer is deposited over the patterned p-metal and the p-type semiconductor. The negative photoresist is then exposed from the back side of the substrate, thus exposing the regions of the negative photoresist that are not masked by the p-metal. The negative photoresist is then developed to expose the p-metal.