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Automatic Dielectric Quality Evaluating System

IP.com Disclosure Number: IPCOM000082977D
Original Publication Date: 1975-Mar-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Anolick, ES: AUTHOR

Abstract

An automatic dielectric quality evaluating system is shown in the figure. Kerf devices, such as simple capacitors for thick oxides or gate chains for Field-effect transistor (FET) products, are incorporated into product wafers. The wafers are then brought singly to a probe station and heated to 200 to 250 degrees C. The probe station could handle 50 capacitors simultaneously to save time per wafer.

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Automatic Dielectric Quality Evaluating System

An automatic dielectric quality evaluating system is shown in the figure. Kerf devices, such as simple capacitors for thick oxides or gate chains for Field-effect transistor (FET) products, are incorporated into product wafers. The wafers are then brought singly to a probe station and heated to 200 to 250 degrees C. The probe station could handle 50 capacitors simultaneously to save time per wafer.

A ramp voltage is applied at a uniform rate of 0.5v/sec up to 20v for 700 Angstroms FET devices, or 2.86v/sec up to 114 volts for 4000 Angstrom FET devices. This will involve 50 capacitors simultaneously with a total time of testing each wafer of 40 seconds.

If one capacitor fails (2%), then the wafer is marginal, and if two capacitors fail, the wafer is rejected. The criteria for fail-reject is set by product requirements and can vary from the above example.

The suggested technique is based upon an established relationship between breakdown voltage and lifetime of a particular defect. Thus, it is possible to predict the reliability of a product relative to time-dependent breakdown from knowledge of the time-zero breakdown. This approach can also be applied to a rapid evaluation of process or product changes on developed products right on the manufacturing line. The possibility exists of using time-zero characteristics to evaluate the reliability associated with other modes of failure with the same type of flow.

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