Varian Associates, Inc.

Susan Benjamin Felch

Ronald A Powell

David L Chapek

Michael William Kissick

Terry T Sheng

Charles B Cooper, Iii

Charles E Van Wagoner

Tienyu Terry Sheng

Shamim Muhammad Malik

An apparatus for improving dose uniformity in the PLAsma Doping (PLAD) ion implantation of a target material is described. By providing means for simultaneously biasing both the electrode, upon which the target is disposed, and a separately biasable concentric structure introduced about the electrode and sufficiently close to the target, together with means for adjustable bias variation between the electrode and the structure one can sufficiently adjust the shape of the implantation plasma, e.g. induced electric field and plasma sheath thickness, in order to effectively provide a uniform dose distribution during PLAD ion implantation processes.

Apparatus for obtaining dose uniformity in plasma doping (PLAD) ion

A charge measuring system for determining implantation dose in a PI.sup.3 system with means to compensate for current in the charge sensor which does not arise from positive ions arriving on the wafer.

Charge monitor for high potential pulse current dose measurement

A method of mapping implanted ion dose uniformity is disclosed in which wafers of polysilicon-on-silicon or polysilicon-on-oxidized-silicon are implanted with the ion dose to be mapped and then scanned in a spectrophotmeter using monochromatic radiation. An interference spectral technique is used to achieve improved sensitivity while preserving thermal and electrical properties close to those of actual devices.

Method of mapping ion implant dose uniformity

A probe having four spring-loaded tips contacts the backside of a semiconductor wafer in a processing machine. A current is induced across the outer tips and a voltage proportional to the sheet resistance of the wafer is measured across the inner tips. Wafer thickness is used to convert sheet resistance to bulk resistivity. Data on resistivity as a function of temperature is used to determine wafer temperature.

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Los Altos, CA, United States of America

Susan Benjamin Felch