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Browse Prior Art Database

A Simple Defect Free Frontside Substrate Contact

IP.com Disclosure Number: IPCOM000108421D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 31K

Publishing Venue

IBM

Related People

Pak, MS: AUTHOR

Abstract

A simple method of contacting the semiconductor substrate from the circuit side, through a deep trench, is described.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

A Simple Defect Free Frontside Substrate Contact

      A simple method of contacting the semiconductor substrate from
the circuit side, through a deep trench, is described.

      During the standard trenching operation, the substrate contact
trench is also formed.  The width of the substrate contact trench
must be such that the selected thickness of the high conductivity
material, such as P+ or N+ polysilicon, will seal off the narrow
substrate contact trench without sealing off the normal trenches from
which the conductive material would be removed, subsequently.
Thereafter, the normal trench operations would occur.

      As an example, 0.7 mm-wide standard trenches are dug.
Conformally deposited over the substrate is 4,500 +- 300A CVD
Ppolysilicon, completely filling the narrow substrate contact
trenches but not the standard, wide trenches.  An isotropic etch is
applied which removes the P+ polysilicon everywhere except the
substrate contact trench.  An optional wet etch may be applied to
remove any contaminants or crystal defects.  Standard trench fill
operations may now begin.

      Disclosed anonymously.