Browse Prior Art Database

Automated Spectrophotometer Tool

IP.com Disclosure Number: IPCOM000099615D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 5 page(s) / 168K

Publishing Venue

IBM

Related People

Jurgens, JJ, JR: AUTHOR [+7]

Abstract

This article describes a machine tool which automatically handles five sizes of wafers from a cassette to a measurement and inspection station and automatically measures the thickness of thin semitransparent films on substrates by analysis of interference spectra produced when white light is reflected off the surface of the film.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 51% of the total text.

Automated Spectrophotometer Tool

       This article describes a machine tool which automatically
handles five sizes of wafers from a cassette to a measurement and
inspection station and automatically measures the thickness of thin
semitransparent films on substrates by analysis of interference
spectra produced when white light is reflected off the surface of the
film.

      The tool is composed of the following major components, as
shown in front view in Fig. 1.
      1.   Wafer handler
      2.   Measurement and inspection station
      3.   Leitz automatic film thickness measurement system
      4.   Operator console
      5.   Industrial computer
      6.   Tool controller
      7.   Film thickness measurement system controller

      The tool is completely automated with manual override
capability.  The industrial computer 5 is the host controller.  It
talks to the tool controller and the film thickness measurement
system controller through serial ports RS-232C (not shown) where the
program is written in C language.  The tool controller is an Intel
8088 microprocessor- based system.

      The tool is designed and programmed to handle five sizes of wa-
fers, namely 200, 150, 125, 100 and 82.5 millimeters.

      There are four cycles in the auto mode of operation. They are
as follows:
      A.   Prepare wafer
      B.   Load wafer
      C.   Measurement
      D.   Return wafer

      Fig. 2 is a top view of the tool, and Fig. 3 is a
side view of the measurement system.  In operation, a transport 8 is
retracted and in down position.  The transport 8 moves to an elevator
10.  After the movement is complete, the transport 8 extends and a
tongue vacuum 9 is turned on.  The transport 8 goes up, and the wafer
is picked up.  The transport 8 retracts after the tongue vacuum
switch is made.

      The transport 8 moves to an orientor 12.  After moving is
complete, the transport 8 extends.  After the extend switch is made,
the transport 8 goes down and the tongue vacuum 9 is turned off to
release the wafer on to the orientor 12.  A stage vacuum 13 is turned
on to hold the wafer in place.

      The orientor 12 finds the notch of the wafer and places it in
the 12 o'clock position.

      The transport 8 extends, and the tongue vacuum 9 is turned on.
Stage vacuum 13 is turned off, and the transport 8 goes up.  The
tongue vacuum 9 removes the wafer from the stage vacuum 13.  The
transport 8 retracts after the tongue vacuum 9 switch is made.

      The transport 8 moves to the measurement and inspection
station. After moving is complete, a microscope 22 is driven to the
upper limit.  The X stage 14 and the Y stage 15 move to a hands-off
position.  Theta stage 16, which holds a chuck vacuum 17, moves to
home position.  Microscope table 20 is in locking position.  The
transport 8 goes up and extends. The tongue vacuum...