Sensitive method of evaluating process induced damage in MOSFETs using a differential amplifier operational principle
AssigneeAdvanced Micro Devices, Inc.
InventorsNguyen D. Bui, Scott Zheng
Life of this patent
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Abstract
Techniques for measuring process induced damage, such as damage experienced during plasma etching or ion implementation, utilize a differential amplifier having multi-layer antennas (capacitors) of different sizes formed on respective inputs. Measurement of .DELTA.Ids (the difference between Ids.sub.1 and Ids.sub.2 off a MOSFET of the differential pair) or .DELTA.Idlin provides a sensitive and accurate measure of process induced damage. The techniques can be applied to monitor process induced damage while the manufacturing process is ongoing or as a measure of quality of the finished product.
Claims4
A method evaluating process induced damage during fabrication of a semiconductor product, comprising the steps of:
- a. forming a differential amplifier on said semiconductor product, said differential amplifier having first and second inputs with said first input connected to a gate of a first MOSFET and said second input connected to a gate of a second MOSFET, said first input connected also to a first size antenna and said second input connected also to a second, different size antenna, with said differential amplifier and each antenna being formed on the semiconductor product during fabrication;
- b. inducing test signals to said semiconductor product;
- and
- c. measuring a difference between the drain source current of the first MOSFET and the drain source current of the second MOSFET (.DELTA.lds) or a difference between the drain current of the first MOSFET and the drain current of the second MOSFET when the first and second MOSFETs are operating in a linear region (.DELTA.Idlin), as an indication of the amount of process induced damage the product suffered during fabrication.
A method of evaluating process induced damage during fabrication of a semiconductor product, comprising the steps of:
- a. forming a differential amplifier on said semiconductor product, said differential amplifier having first and second inputs with said first input connected to a gate of a first MOSFET and said second input connected to a gate of a second MOSFET, said first input connected also to a first size antenna and said second input connected also to a second, different size antenna, with said differential amplifier and each antenna being formed on the semiconductor product prior to fabrication;
- b. inducing test signals to said semiconductor product;
- and
- c. measuring a difference between the drain source current of the first MOSFET and the drain source current of the second MOSFET (.DELTA.lds) or a difference between the drain current of the first MOSFET and the drain current of the second MOSFET when the first and second MOSFETs are operating in a linear region (.DELTA.Idlin), as an indication of the amount of process induced damage the product suffered during fabrication.
Dependencies are inferred from the claim text.