Browse Prior Art Database

Integrated P/N Diode for Stress Measurement

IP.com Disclosure Number: IPCOM000107924D
Original Publication Date: 1992-Mar-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 39K

Publishing Venue

IBM

Related People

Beyer, KD: AUTHOR [+3]

Abstract

The I/V characteristic of a p/n junction depends on the magnitude of the mechanical stress. For a given fixed current, the higher the mechanical stress is on the diode the lower the forward voltage will be measured. Thus, a p/n junction can be utilized for on-chip stress monitoring.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 98% of the total text.

Integrated P/N Diode for Stress Measurement

      The I/V characteristic of a p/n junction depends on the
magnitude of the mechanical stress.  For a given fixed current, the
higher the mechanical stress is on the diode the lower the forward
voltage will be measured.  Thus, a p/n junction can be utilized for
on-chip stress monitoring.

      Normally, Raman spectroscopy is used to measure the stress on
the wafer surface.  With this approach, sometimes a surface
dielectric film, such as thermal oxide or nitride, must be stripped.
Therefore, Raman spectroscopy is a destructive method.  A
nondestructive measurement of the stress on the silicon surface or in
silicon bulk can only be obtained by placing a p/n junction and
measuring the I/V characteristics of the diode.  Such diodes can be
either fabricated at the surface or at the bottom of the trench. In
addition, by varying the trench depth, the p/n diodes can sense the
stress at different depths in the bulk silicon by measuring the
respective I/V characteristics.

      The advantages of this method are:
      1.   a nondestructive measurement
      2.   test sites can be easily integrated into device
fabrication.
      3.   direct measurement is not affected by any environmental
factor such as stripping a dielectric film
      4.   a three-dimensional stress mapping can be obtained, and
      5.   in-situ stress variation during a thermal cycle can be
monitored.

      D...