Method and apparatus for photomask plasma etching

• US 20060000802A1
• Filed: 06/30/2004
• Published: 01/05/2006
• Est. Priority Date: 06/30/2004
• Status: Abandoned Application

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Kumar, Ajay, Anderson, Scott Alan, Satitpunwaycha, Peter, Chandrachood, Madhavi, Yau, Wai Fan
• Application Number:
  US10/882,084
• Publication Number:
  US 20060000802A1
• Time in Patent Office: Days
• US Class Current: 216/67
• CPC Class Codes: G03F 1/80 Etching
• CPC Class Codes: H01J 2237/0225 Detecting or monitoring foreign particles
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01J 37/32422 Arrangement for selecting ions or species in the plasma
• CPC Class Codes: H01J 37/32623 Mechanical discharge control means
• CPC Class Codes: H01J 37/32651 Shields, e.g. dark space shields, Faraday shields
• CPC Class Codes: H01J 37/32871 Means for trapping or directing unwanted particles

Abstract

A method and apparatus for etching photomasks is provided herein. In one embodiment, a method of etching a photomask includes providing a process chamber having a substrate support pedestal adapted to receive a photomask substrate thereon. An ion-radical shield is disposed above the pedestal. A substrate is placed upon the pedestal beneath the ion-radical shield. A process gas is introduced into the process chamber and a plasma is formed from the process gas. The substrate is etched predominantly with radicals that pass through the shield.

Claims

1. An apparatus for plasma etching, comprising:

a process chamber;

a substrate support pedestal disposed in the process chamber and adapted to receive a photomask reticle thereon;

an RF power source for forming a plasma within the chamber; and

an ion-radical shield disposed in the chamber above the pedestal and adapted to control the spatial distribution of charged and neutral species of the plasma.

2. The apparatus of claim 1, wherein the RF power source is inductively coupled to the process chamber.

3. The apparatus of claim 1, wherein the apertures are about 1.25 cm in diameter.

4. The apparatus of claim 1, wherein the shield is disposed about 5 cm above the substrate.

5. The apparatus of claim 1, wherein the shield further comprises:

a substantially flat member electrically isolated from the chamber; and

a plurality of apertures.

6. The apparatus of claim 5, wherein the member further comprises:

a plate having the plurality of apertures formed therethrough.

7. The apparatus of claim 6, wherein the apertures have a hole size, shape, position, and distribution over the surface of the plate to define an ion to radical density ratio proximate the substrate.

8. The apparatus of claim 6, further comprising:

a plurality of support legs supporting the plate above the pedestal.

9. The apparatus of claim 8, wherein the legs support the plate in a substantially parallel, spaced apart relation with respect to the pedestal.

10. The apparatus of claim 8, further comprising:

an edge ring disposed about a perimeter of an upper surface of the support pedestal and having the plurality of support legs extending therefrom.

11. The apparatus of claim 6, wherein the plate is fabricated from at least one of ceramic, quartz, or anodized aluminum.

12. The apparatus of claim 5, wherein the member is fabricated from at least one of ceramic, quartz, or anodized aluminum.

13. A method of etching a photomask, comprising:

providing a process chamber having a substrate support pedestal adapted to receive a photomask reticle thereon and an ion-radical shield disposed above the pedestal;

placing a reticle upon the pedestal;

introducing a process gas into the process chamber;

forming a plasma from the process gas; and

etching the reticle predominantly with radicals that pass through the shield.

14. The method of claim 13, wherein the step of etching further comprises:

forming a potential upon a surface of the shield.

15. The method of claim 13, wherein the step of introducing a process gas further comprises:

introducing a chlorine containing gas into the chamber.

16. The method of claim 13, wherein the step of forming a plasma further comprises:

inductively coupling RF power to an antenna disposed proximate the process chamber.

17. The method of claim 13, wherein the step of etching the substrate predominantly with radicals further comprises:

defining a hole size, shape, position, and distribution over the surface of the shield to control the ion to radical density ratio proximate the reticle.

18. A method of etching a photomask, comprising:

providing a process chamber having a substrate support pedestal adapted to receive a photomask reticle thereon and an ion-radical shield disposed above the pedestal;

placing a reticle having an exposed chromium layer to be etched upon the pedestal;

applying a reticle bias power between about 5 and about 500 Watts;

introducing a halogen containing process gas into the process chamber;

forming a plasma from the process gas by applying an RF power between about 200 and about 2000 Watts; and

etching the reticle predominantly with radicals that pass through the shield.

19. The method of claim 18, wherein the step of introducing a halogen containing process gas further comprises:

introducing a chlorine containing gas into the process chamber.

20. The method of claim 18, further comprising:

introducing an oxygen containing gas into the process chamber.

21. An apparatus for plasma etching, comprising:

a process chamber;

a substrate support pedestal disposed in the process chamber and adapted to receive a photomask reticle thereon;

an RF power source for forming a plasma within the chamber; and

means for controlling the spatial distribution of charged and neutral species of the plasma.

22. A method of etching a photomask, comprising:

forming a plasma comprising ions and radicals in a first region of a chamber;

filtering radicals from the plasma; and

etching a photomask substrate predominantly with radicals that are filtered from the plasma.