Browse Prior Art Database

Contamination Monitor for Ion Implant Tools

IP.com Disclosure Number: IPCOM000049334D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Montillo, FJ: AUTHOR [+2]

Abstract

This article describes a method for determining the degree of contamination introduced into an ion-implantation process by the implanting apparatus. The method features building a MOS capacitor test structure by implantation using the apparatus to be characterized, measurement of the test structure's charge retention time, and correlation of the charge retention time measurement to impurity (contamination) level.

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Contamination Monitor for Ion Implant Tools

This article describes a method for determining the degree of contamination introduced into an ion-implantation process by the implanting apparatus. The method features building a MOS capacitor test structure by implantation using the apparatus to be characterized, measurement of the test structure's charge retention time, and correlation of the charge retention time measurement to impurity (contamination) level.

In practicing the test method, the test structure is formed by:

1) providing a 10 omega -cm p-type silicon substrate;

2) cleaning and forming oxide over the substrate;

3) removing the oxide at the back side of the substrate;

4) blanket ion implanting an impurity layer in the substrate

backside,

for example, arsenic at 2 x 10/16/ cm/-3/ at 50 KeV;

5) nitrogen annealing the substrate at 1000 degrees C for 120

120 minutes;

6) providing a MOS dot, metallization pattern at the

substrate's front side; and

7) sintering the substrate in forming gas at 400 degrees C.

Following formation of the test structure, charge retention time measurements are made. For the charge retention time measurements, a voltage step is applied to the MOS capacitor test structures individually to drive the structures from the accumulation state into deep depletion. During this interval, the change in high frequency capacitance of the structure with time is measured.

Following the measurement, the results can be analyzed to determine the impur...