Method and apparatus for adaptive sampling based on process covariance
US6985825B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 2003 |
| Grant date | Jan 10, 2006 |
| Priority date | — |
| Expiry date | Apr 12, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P90/02
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A method includes processing a plurality of workpieces to form at least one feature on each workpiece. A plurality of characteristics of the feature is measured. A covariance matrix including diagonal and non-diagonal terms for the plurality of characteristics measured is constructed. At least the non-diagonal terms of the covariance matrix are monitored. A sampling plan for measuring the workpieces is determined based on the monitoring. A system includes a plurality of tools, at least one metrology tool, and a sampling controller. The tools are configured to process a plurality of workpieces to form at least one feature on each workpiece. The metrology tool is configured to measure a plurality of characteristics of the feature. The sampling controller is configured to construct a covariance matrix including diagonal and non-diagonal terms for the plurality of characteristics measured, monitor at least the non-diagonal terms of the covariance matrix, and determine a sampling plan for measuring the workpieces based on the monitoring.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.