Quantitative secondary electron detection
AssigneeScience Tomorrow LLC
InventorsJyoti Agrawal, David C. Joy, Subuhadarshi Nayak
Life of this patent
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Abstract
Quantitative Secondary Electron Detection (QSED) using the array of solid state devices (SSD) based electron-counters enable critical dimension metrology measurements in materials such as semiconductors, nanomaterials, and biological samples (FIG. 3). Methods and devices effect a quantitative detection of secondary electrons with the array of solid state detectors comprising a number of solid state detectors. An array senses the number of secondary electrons with a plurality of solid state detectors, counting the number of secondary electrons with a time to digital converter circuit in counter mode.
Claims18
A quantitative secondary electron detection device comprising:
- a circuit to aggregate a count of a number of secondary electrons;
- a circuit to store a count of a number of secondary electrons;
- a circuit comprising a time to digital converter;
- an electrical device or a magnetic device, configured to attract secondary electrons in a disperse pattern over an array of PIN diodes;
- wherein the PIN diodes are configured to detect and count a number of secondary electrons over a dwell time.
A method for a quantitative detection of secondary electrons with an array of PIN diodes comprising the steps:
- scanning a beam of charged particles over a target;
- attracting a number of secondary electrons with a faraday cage;
- distributing a number of secondary electrons over the array;
- detecting the number of secondary electrons with the array, creating a current change and a voltage change;
- aggregating data consisting of either the current change, the voltage change, or both the current change and the voltage change over the array of solid state detectors;
- counting the number of secondary electrons with a time to digital converter circuit in counter mode;
- assigning the count to a pixel;
- and
- resetting the array.
A quantitative detection device for the detection of photons and/or particles comprising:
- a circuit to aggregate a count of photons and/or particles;
- a circuit to store the count of photons and/or particles;
- a circuit comprising a time to digital converter;
- a device configured to disperse photons and/or particles from a single spot on an object over an array of PIN diodes;
- wherein the array comprises:
- at least a number of PIN diodes and further wherein the number of detectors is greater than a rate of photons or particles impinging upon the array divided by a switching frequency of the solid state detectors.
Dependencies are inferred from the claim text.