Claims
- 1. An alignment mark formed within a device, for indexing said device, said alignment mark comprising:a substrate; at least one isolation trench oxide formed upon said substrate with a first thickness; at least one additional oxide region, having a second thickness, formed adjacent said at least one isolation trench oxide, said second thickness being less than said first thickness; and a planarized opaque layer formed upon said isolation trench oxide, a wavelength of an energy source used to detect a boundary between said substrate and said isolation trench oxide being selected in accordance with an absorption coefficient and thickness of said planarized opaque layer, wherein said at least one additional oxide region is a gate oxide of a transistor.
- 2. An alignment mark according to claim 1, wherein said planarized, opaque layer includes:multiple planarized, opaque layers.
- 3. An alignment mark according to claim 2, further comprising:at least one resist layer formed upon said planarized, opaque layer.
- 4. An alignment mark according to claim 1, wherein said planarized, opaque layer is a polysilicon layer.
- 5. An alignment mark according to claim 1, wherein said energy source used for said boundary detection is a laser source.
- 6. An alignment mark according to claim 5, wherein said laser source is an infrared source.
Parent Case Info
This application is a divisional of application Ser. No. 08/919,200 , filed Aug. 28, 1997, now U.S. Pat. No. 5,852,497.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
5925937 |
Jost et al. |
Jul 1999 |
|
6242816 |
Stanton et al. |
Jun 2001 |
|