SECURE PHOTOMASK WITH BLOCKING APERTURE

• US 20080261126A1
• Filed: 04/18/2008
• Published: 10/23/2008
• Est. Priority Date: 04/20/2007
• Status: Active Grant

• Current Assignee: Phototronics Incorporated
• Original Assignee: Phototronics Incorporated
• Inventors: Progler, Christopher J.
• Granted Patent: US 7,851,110 B2
• Time in Patent Office: Days
• US Class Current: 430/5
• CPC Class Codes: G03F 1/38 Masks having auxiliary features, e.g. special coatings or marks for alignment or testing; Preparation thereof
• CPC Class Codes: G03F 1/40 Electrostatic discharge [ESD] related features, e.g. antistatic coatings or a conductive metal layer around the periphery of the mask substrate

Abstract

A secure photomask including a substrate having one or more pattern layers formed thereon and a blocking aperture disposed below the one or more pattern layers that prevents at least one of unauthorized use and copying of the photomask.

Claims

1. A secure photomask comprising:

a substrate comprising one or more pattern layers formed thereon; and

a blocking aperture disposed below the one or more pattern layers that prevents at least one of unauthorized use and copying of the photomask.

2. The secure photomask of claim 1, wherein the blocking aperture is an electrochromic film.

3. The secure photomask of claim 2, wherein the electrochromic film comprises tungsten oxide.

4. The secure photomask of claim 2, further comprising an electric charge delivery element that delivers electric signals to the electrochromic film to switch the electrochromic film from being substantially opaque to substantially transparent and from being substantially transparent to substantially opaque.

5. The secure photomask of claim 1, wherein the one or more pattern layers comprise at least one antireflective layer.

6. The secure photomask of claim 1, wherein the one or more layers comprise at least one opaque layer.

7. The secure photomask of claim 1, wherein the one or more layers comprise at least one partially transparent layer.

8. The secure photomask of claim 1, wherein the blocking aperture is disposed between the substrate and the pattern layers.

9. The secure photomask of claim 1, wherein the blocking aperture is disposed below the substrate.

10. A secure photomask blank comprising:

a substrate comprising one or more layers formed thereon; and

a blocking aperture disposed below the one or more layers that prevents at least one of unauthorized use and copying of a photomask formed from the photomask blank.

11. The secure photomask blank of claim 10, wherein the blocking aperture is an electrochromic film.

12. The secure photomask blank of claim 11, wherein the electrochromic film comprises tungsten oxide.

13. The secure photomask blank of claim 11, further comprising an electric charge delivery element that delivers electric signals to the electrochromic film to switch the electrochromic film from being substantially opaque to substantially transparent and from being substantially transparent to substantially opaque.

14. The secure photomask blank of claim 10, wherein the one or more layers comprise at least one antireflective layer.

15. The secure photomask blank of claim 10, wherein the one or more layers comprise at least one opaque layer.

16. The secure photomask blank of claim 10, wherein the one or more layers comprise at least one partially transparent layer.

17. The secure photomask blank of claim 10, wherein the blocking aperture is disposed between the substrate and the one or more layers.

18. The secure photomask blank of claim 10, wherein the blocking aperture is disposed below the substrate.