Utilizing electrical performance data to predict CD variations across stepper field
US6562639B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 2001 |
| Grant date | May 13, 2003 |
| Priority date | — |
| Expiry date | Nov 6, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/34
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In order to determine an amount of critical dimension variation to expect across a surface of a final production wafer, a plurality of test structures are formed on a test wafer. The test structures are preferably of a type commonly found on the final production wafer and may for example, include transistors, ring oscillators, resistors and/or diodes. Electrical parameter testing of the test structures is next conducted in order to obtain one or more electrical performance values for each test structure. For example, the electrical performance values may correspond to processing speed, drive current, and/or off-state current of the test structures. A correlation between the electrical performance values and expected critical dimension variations is then performed and a report is generated providing the expected critical dimension variations across the surface of the wafer. Expected critical dimension variations may be accounted for by varying characteristics of devices used during a photolithographic transfer process to the final production wafers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.