Alignment measuring system and method of determining alignment in a photolithography process
US7242476B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 12, 2004 |
| Grant date | Jul 10, 2007 |
| Priority date | — |
| Expiry date | Aug 25, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7088
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An alignment measuring system includes a focusing diode, a light source, an image sensor, first and second splitters, and a controller. The first splitter directs a portion of light from the light source toward a wafer, and directs light returned by the wafer to the second splitter. The second splitter directs a first portion of the light toward the image sensor, and a second portion of the light toward the focusing diode, and control the ratio of the first and second portions in response to a control signal from the controller. The image sensor receives the first portion of light and produces a detection signal. The controller receives the detection signal, determines an alignment state of the wafer, and controls a stage to align and position the wafer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.