CPL mask and a method and program product for generating the same

• US 20080067143A1
• Filed: 07/06/2007
• Published: 03/20/2008
• Est. Priority Date: 07/06/2006
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Masktools B.V. (ASML Holding NV)
• Inventors: Wampler, Kurt, Broeke, Douglas, Chen, Jang
• Granted Patent: US 7,998,355 B2
• Time in Patent Office: Days
• US Class Current: 216/12
• CPC Class Codes: G03F 1/32 Attenuating PSM [att-PSM], e.g. halftone PSM or PSM having semi-transparent phase shift portion,; Preparation thereof
• CPC Class Codes: G03F 1/34 Phase-edge PSM, e.g. chromeless PSM; Preparation thereof

Abstract

A method of generating a mask for printing a pattern including a plurality of features. The method includes the steps of depositing a layer of transmissive material having a predefined percentage transmission on a substrate; depositing a layer of opaque material on the transmissive material; etching a portion of the substrate, the substrate being etched to a depth based on an etching selectivity between the transmissive layer and the substrate; exposing a portion of the transmissive layer by etching the opaque material; etching the exposed portion of the transmissive layer so as to expose an upper surface of the substrate; where the exposed portions of the substrate and the etched portions of the substrate exhibit a predefined phase shift relative to one another with respect to an illumination signal.

Claims

1. A method of a forming a mask for printing a pattern comprising a plurality of features, said method comprising the steps of:

depositing a layer of transmissive material having a predefined percentage transmission on a substrate;

depositing a layer of opaque material on said transmissive material;

etching a portion of said substrate, said substrate being etched to a depth based on an etching selectivity between said transmissive layer and said substrate;

exposing a portion of said transmissive layer by etching said opaque material;

etching said exposed portion of said transmissive layer so as to expose said upper surface of said substrate;

wherein said exposed portions of said substrate and said etched portions of said substrate exhibit a predefined phase shift relative to one another with respect to an illumination signal.

2. The method of a forming a mask according to claim 1, wherein said etching depth of said substrate is equal to a target depth minus a predefined delta, said predefined delta corresponding to a thickness of said transmissive layer times the etching selectivity between said transmissive layer and said substrate.

3. The method of a forming a mask according to claim 1, wherein said layer of opaque material comprises chrome.

4. The method of a forming a mask according to claim 1, wherein said transmissive layer comprises MoSiON.

5. The method of a forming a mask according to claim 1, wherein said transmissive layer has a percentage transmission in the range of 5 to 12 percent.

6. The method of a forming a mask according to claim 1, wherein said opaque material operates as a hard mask during the etching of said substrate.

7. The method of a forming a mask according to claim 1, wherein said etched portion of said substrate forms a background portion of said mask, said background portion being a clear field.

8. A computer readable medium for controlling a device for generating a mask for imaging a target pattern having a plurality of features, the process of generating said mask comprising the steps of:

depositing a layer of transmissive material having a predefined percentage transmission on a substrate;

depositing a layer of opaque material on said transmissive material;

etching a portion of said substrate, said substrate being etched to a depth based on an etching selectivity between said transmissive layer and said substrate;

exposing a portion of said transmissive layer by etching said opaque material;

etching said exposed portion of said transmissive layer so as to expose said upper surface of said substrate;

wherein said exposed portions of said substrate and said etched portions of said substrate exhibit a predefined phase shift relative to one another with respect to an illumination signal.

9. The computer readable medium according to claim 8, wherein said etching depth of said substrate is equal to a target depth minus a predefined delta, said predefined delta corresponding to a thickness of said transmissive layer times the etching selectivity between said transmissive layer and said substrate.

10. The computer readable medium according to claim 8, wherein said layer of opaque material comprises chrome.

11. The computer readable medium according to claim 8, wherein said transmissive layer comprises MoSiON.

12. The computer readable medium according to claim 8, wherein said transmissive layer has a percentage transmission in the range of 5 to 12 percent.

13. The computer readable medium according to claim 8, wherein said opaque material operates as a hard mask during the etching of said substrate.

14. The computer readable medium according to claim 8, wherein said etched portion of said substrate forms a background portion of said mask, said background portion being a clear field.

15. A device manufacturing method comprising the steps of:

(a) providing a substrate that is at least partially covered by a layer of radiation-sensitive material;

(b) providing a projection beam of radiation using an imaging system;

(c) generating a mask utilized to endow the projection beam with a pattern in its cross-section;

(d) projecting the patterned beam of radiation onto a target portion of the layer of radiation-sensitive material,

wherein, in step (c), said mask is formed by a method comprising the steps of;

depositing a layer of transmissive material having a predefined percentage transmission on a substrate;

depositing a layer of opaque material on said transmissive material;

etching a portion of said substrate, said substrate being etched to a depth based on an etching selectivity between said transmissive layer and said substrate;

exposing a portion of said transmissive layer by etching said opaque material;

etching said exposed portion of said transmissive layer so as to expose said upper surface of said substrate;

wherein said exposed portions of said substrate and said etched portions of said substrate exhibit a predefined phase shift relative to one another with respect to an illumination signal.