Back to results
US 2022/0066410 A1Published application
Sequenced Approach For Determining Wafer Path Quality
AssigneePDF Solutions, Inc.
InventorsTomonori Honda, Richard Burch, Jeffrey Drue David
Life of this patent
Estimating the term…
Abstract
Wafer quality is determined by modeling equipment history as a sequence of events, then evaluating anomalous results for individual events. Identifying an event that generates bad wafers narrows the list of possible root causes.
Claims15
A method, comprising:
- analyzing an equipment history for a lot of semiconductor wafers produced in a plurality of processing steps as a sequence of events including a corresponding transition between each event;
- for each transition between events, computing a first statistical indicator for good wafers and a second statistical indicator for bad wafers;
- detecting a data excursion for at least a first transition wherein the first statistical indicator exceeds a first threshold or the second statistical indicator exceeds a second threshold;
- and
- identifying a plurality of possible root causes for the data excursion based on a comparison of the first and second indicators for the first transition.
2 more elements
A method, comprising:
- obtaining an equipment history for a lot of semiconductor wafers produced in a plurality of processing steps;
- and
- generating a first model of the equipment history for the lot as a sequence of a plurality of events including a transition between each event, each event corresponding to one of the plurality of processing steps, the model configured for:
- detecting a data excursion having an indicator exceeding a threshold for at least one of the transitions between a sequential pair of the plurality of events;
- and
- identifying a plurality of possible root causes for the data excursion based on the at least one transition and a pair of the processing steps that correspond to the sequential pair of the plurality of events.
3 more elements
A non-transitory computer-readable medium having instructions which, when executed by a processor cause the processor to:
- analyze an equipment history for a lot of semiconductor wafers produced in a plurality of processing steps as a sequence of events including a corresponding transition between each event;
- for each transition between events, compute a first statistical indicator for good wafers and a second statistical indicator for bad wafers;
- detect a data excursion for at least a first transition wherein the first statistical indicator exceeds a first threshold or the second statistical indicator exceeds a second threshold;
- and
- identify a plurality of possible root causes for the data excursion based on a comparison of the first and second statistical indicators for the first transition.
2 more elements
Dependencies are inferred from the claim text.