Dry Etching of Deep Backside Vias in InP

Maria Huffman 1 , Timothy Engel 1 , Nicholas Pfister 1 , Gabriel Arevalo 1 , Tom Brown 1 ,

Maya Farhoud 1 , Ron Miller 1 , Ben Keppeler 1 , John Staroba 1 , Richard Jefferies 2 .

1 Agilent Technologies Inc., Microwave Technology Center, 1400 Fountaingrove Parkway, Santa Rosa, CA

95403. Email: maria_huffman@agilent.com; Phone:707-577-4895 2 Trikon Technologies Ltd., Ringland Way, Newport, NP18 2TA, UK


Keywords: Dry Etching, Inductively Coupled Plasma, InP, Backside Vias



For the last several years, there has been great interest in InP HBTs due to the attractive properties of InP and its lattice matched materials used for high-speed digital circuit fabrication. Based on the successful introduction of high performance circuits on GaAs with backside vias, the same approach has been used for InP. The purpose of this work is to present results from dry etching of deep backside vias in InP in a high density, inductively coupled plasma reactor. All etching has been carried out on 3-inch wafers mounted on sapphire carriers. Our results show ~100 m deep vias with good profiles, average InP etch rates of 1.5 m/min and selectivities of InP to mask (photoresist) =10:1. This process is acceptable to introduce to our manufacturing environment.



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