Development of an Advanced Diagnostic System for Sub-PPT Metal Contamination in Silicon Wafer Manufacturing and Processing


DIASYSCON - 7327

Keywords contamination control, metal contamination, injection scanning lifetime imaging


Start Date: 27-MAY-92 / Duration: 36 months

[ contact / participants ]


Objectives

Future IC manufacturing processes will demand significant improvements in the purity of the starting material and better control of individual process steps. Typical metal concentrations in starting bulk Si material are currently of the order of 10{11} to 10{12} cm{-3}. Improvements of one to two orders of magnitude are required for advanced IC devices. In order to meet this technological goal, new analytical strategies need to be developed. The overall objective of DIASYSCON is to develop an easy-to-use advanced diagnostic system for ultra low metal contamination control, based on injection scanning life-time imaging combined with a new generation of monitor wafers. This system will be applied in case studies from wafer-manufacturing, IC production and process development, and is expected to lead to significant improvements in IC yields.

A four-step approach has been adopted:

Progress and Results

Rapid advances have been made in the application of injection scanning techniques to problems of contamination in a wide variety of technologically relevant situations. Working with a prototype system, methods for the detection, discrimination and imaging of FeB, Fe[1] and oxygen precipitates in concentrations below 10{10} cm{-3} have been worked out. Highly sensitive CZ silicon wafers have been produced with minority carrier diffusion lengths of greater than 2 mm. In addition to this, an effective increase in system sensitivity of 35 times has been demonstrated. Special monitor wafers for the detection of low levels of Cu and Ni have been developed. "Precipitation hard" CZ silicon wafers were demonstrated to be highly effective in the investigation of contamination in nearly arbitrary process conditions, including extremely long, high-temperature processes. An important spin-off has led to processes for the production of a "precision-controlled precipitation" wafer.


CONTACT POINT

Dr Robert Falster
MEMC Electronic Materials SpA
Viale Gherzi 31
I - 28100 Novara
tel: + 39 / 321-442-394
fax: + 39 / 321-490-041
telex: 200486

Participants

MEMC ELECTRONIC MATERIALS - I - C
GESELLSCHAFT FÜR MESSTECHNIK
UND TECHNOLOGIE MBH - D - P
SGS-THOMSON MICROELECTRONICS SRL - I - P
CEA - F - P


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DIASYSCON - 7327, December 1993


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html version of synopsis by Nick Cook