Browse Prior Art Database

Improved Guard Plate

IP.com Disclosure Number: IPCOM000108161D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 58K

Publishing Venue

IBM

Related People

Pistor, RL: AUTHOR [+2]

Abstract

This disclosure describes a technique and fabrication process to provide a high immunity to electrical noise on systems where wafer level devices are tested at elevated temperatures. The disclosed design provides high DC isolation while maintaining stable mechanical and thermal properties.

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

Improved Guard Plate

      This disclosure describes a technique and fabrication process
to provide a high immunity to electrical noise on systems where wafer
level devices are tested at elevated temperatures.  The disclosed
design provides high DC isolation while maintaining stable mechanical
and thermal properties.

      The physical layout of this invention is shown in FIG. 1.  The
top surface of the multi-layer configuration is typically referred to
as the "wafer chuck".  This top surface is where the wafer is applied
and often is used as part of the electrical measurement circuit
during wafer tests.  This application is typically very sensitive to
electrically induced noise generated by the thermal unit.

      This disclosure provides the wafer chuck with a backside
insulator.  this enables one to ground a guard plate which lies
between the wafer chuck and the thermal heaters, which effectively
eliminates the transmitted noise from the thermal unit.

      The key feature of the wafer chuck, in combination with the
heater guard, is the surrounding integral dielectric layer on the
wafer chuck.  The dielectric is a hot deionized water-sealed,
non-porous hard anodized layer which provides for the electrical
isolation of the chuck from the remaining electrical circuits while
maintaining a uniform transfer of temperature through the chuck and
across the entire top surface of the wafer chuck which is plated with
a thin layer of gold.

      Disclo...