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Impurity and Defect Free Silicon Substrates for LSI Devices

IP.com Disclosure Number: IPCOM000082932D
Original Publication Date: 1975-Mar-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Sharma, V: AUTHOR

Abstract

The starting substrates for large-scale integration (LSI) devices have exhibited surface impurities and damaged silicon surfaces, which are caused during the wafer fabrication processes.

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Impurity and Defect Free Silicon Substrates for LSI Devices

The starting substrates for large-scale integration (LSI) devices have exhibited surface impurities and damaged silicon surfaces, which are caused during the wafer fabrication processes.

With high-density devices having closer or tighter dimensions and thin epitaxial (2.0 to 3.5 Mu) layers, these defects propagate through and cause high leakage and low-device yields and unreliable performance. This process removes the silicon surface (approx. 1.0 Mu or more) without causing any surface damage to the substrates. The process sequence steps, are as follows:
1. Brush clean to remove the foreign materials. 2. Remove any residual organics from previously used processes during wafer fabrication, using isopropyl alcohol or methyl or trichloro alcohol (5 minutes). 3. Follow by a thorough DI water rinse. Clean with solutions of H(2)SO(4) (at 85 degrees C) for 5 minutes to remove the inorganic or organic contaminates from the surface. This is followed by a DI water rinse. 4. Etch with 25O:1 (HNO(3):HF) for 10 to 30 minutes at room temperature with or without any agitation. This is followed by a DI water rinse.

The substrate surfaces, when inspected under bright light (40,000 Lux) do not show any artifact, e.g., stains, scratches, etc.

The processing of these substrates for devices produces very high device yields by reducing or eliminating defects, which cause leakage.

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