Variable Resist Protecting Groups

• US 20100075238A1
• Filed: 09/16/2009
• Published: 03/25/2010
• Est. Priority Date: 09/19/2008
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Somervell, Mark, Fonseca, Carlos A., Scheer, Steven
• Granted Patent: US 8,129,080 B2
• Time in Patent Office: Days
• US Class Current: 430/30
• CPC Class Codes: G03B 27/54 Lamp housings; Illuminating means
• CPC Class Codes: G03F 7/095 having more than one photosensitive layer G03F7/075 takes precedence
• CPC Class Codes: G03F 7/322 Aqueous alkaline compositions
• CPC Class Codes: G03F 7/325 Non-aqueous compositions

Abstract

A method and system for patterning a substrate using a dual-tone development process is described. The method and system comprise using a resist material having a polymer backbone with a plurality of protecting groups attached thereto to improve process latitude and critical dimension uniformity for the dual-tone development process.

Claims

1. A method of patterning a substrate using a dual-tone development procedure, comprising:

forming a layer of radiation-sensitive material on the substrate, wherein the layer of radiation-sensitive material comprises a resist material having a polymer backbone and a plurality of protecting groups;

creating a first patterned layer of exposed radiation-sensitive material by exposing the layer of radiation-sensitive material using a first EM radiation and a reticle having a plurality of masking features, and heating the first patterned layer of exposed radiation-sensitive material thereby creating a plurality of high exposure regions having a first number of de-protected groups, a plurality of medium exposure regions having a second number of de-protected groups, and a plurality of low exposure regions having a third number of de-protected groups in the low exposure regions;

determining a first threshold profile for a first positive tone development procedure for the first patterned layer of exposed radiation-sensitive material using at least one of the first number of de-protected groups in the high exposure regions, the second number of de-protected groups in the medium exposure regions, and the third number of de-protected groups in the low exposure regions;

determining a first set of limits for a first dual-tone development procedure;

modifying the first threshold profile if the first threshold profile exceeds one or more of the first set of limits; and

developing the first patterned layer of exposed radiation-sensitive material if the first threshold profile does not exceed at least one of the first set of limits.

2. The method of claim 1, wherein the reticle comprises at least one of a phase-shift mask, a tri-tone mask, and a half-tone mask.

3. The method of claim 2, wherein the half-tone mask comprises at least one of a sub-resolution pitch, a sub-resolution size, and a mask edge spacing.

4. The method of claim 1, wherein the resist material comprises at least one of a dual-tone resist, a photo-sensitive acid, a photo-sensitive base, a photo-sensitive protecting group, a photo-sensitive blocking group, a photo-sensitive leaving group, a negative tone polymer, and a positive tone polymer.

5. The method of claim 1, wherein the modifying the first threshold profile further comprises:

determining a first difference between the first threshold profile and a first limit; and

applying first thermal energy to the first patterned layer to de-protect at least one additional protecting group, thereby creating a first modified patterned layer having a first modified number of de-protected groups in the high exposure regions, a second modified number of de-protected groups in the medium exposure regions, and a third modified number of de-protected groups in the low exposure regions, wherein the first thermal energy is determined using at least one of the first difference, the polymer backbone, the first modified number of de-protected groups in the high exposure regions, the second modified number of de-protected groups in the medium exposure regions, and the third modified number of de-protected groups in the low exposure regions.

6. The method of claim 1, wherein the modifying the first threshold profile further comprises:

determining a first difference between the first threshold profile and a first limit; and

applying first optical signal power to the first patterned layer to de-protect at least one additional protecting group, thereby creating a first modified patterned layer having a first modified number of de-protected groups in the high exposure regions, a second modified number of de-protected groups in the medium exposure regions, and a third modified number of de-protected groups in the low exposure regions, wherein the first optical signal power is determined using at least one of the first difference, the polymer backbone, the first modified number of de-protected groups in the high exposure regions, the second modified number of de-protected groups in the medium exposure regions, and the third modified number of de-protected groups in the low exposure regions.

7. The method of claim 6, wherein the first optical signal power is provided by at least one of a single frequency source, multiple frequency source, a coherent source, a non-coherent source, a broadband source, a UV source, a EUV source, an IR source, a flood exposure source, and a visible light source.

8. The method of claim 1, wherein the modifying the first threshold profile further comprises:

determining a first difference between the first threshold profile and a first limit; and

applying a first chemical species to the first patterned layer to de-protect at least one additional protecting group, thereby creating a first modified patterned layer having a first modified number of de-protected groups in the high exposure regions, a second modified number of de-protected groups in the medium exposure regions, and a third modified number of de-protected groups in the low exposure regions, wherein the first chemical species is determined using at least one of the first difference, the polymer backbone, the first modified number of de-protected groups in the high exposure regions, the second modified number of de-protected groups in the medium exposure regions, and the third modified number of de-protected groups in the low exposure regions.

9. The method of claim 8, wherein the first chemical species includes at least one of a developing solution (TMAH), a modified developing solution (TMAH and water), a de-blocking group, a de-protection group, a de-coupling group, and a cleaving group.

10. The method of claim 1, wherein the modifying the first threshold profile further comprises:

determining a first difference between the first threshold profile and a first limit; and

applying second EM radiation to the first patterned layer to de-protect at least one additional protecting group, thereby creating a first modified patterned layer having a first modified number of de-protected groups in the high exposure regions, a second modified number of de-protected groups in the medium exposure regions, and a third modified number of de-protected groups in the low exposure regions, wherein the second EM radiation is determined using at least one of the first difference, the polymer backbone, the first modified number of de-protected groups in the high exposure regions, the second modified number of de-protected groups in the medium exposure regions, and the third modified number of de-protected groups in the low exposure regions.

11. The method of claim 10, wherein the second EM radiation includes at least one of low frequency radiation, HF radiation, VHF radiation, UHF radiation, and microwave radiation.

12. The method of claim 10, wherein a second EM radiation energy is higher than a first EM radiation energy.

13. The method of claim 10, wherein the second EM radiation is applied using at least one of a single frequency source, multiple frequency source, a coherent source, a non-coherent source, a broadband source, a UV source, a EUV source, an IR source, a flood exposure source, and a visible light source.

14. The method of claim 1, wherein the developing the first patterned layer further comprises:

performing a positive development procedure to remove one or more of the high exposure regions from the substrate using a first chemistry; and

performing a negative development procedure to remove one or more of the low exposure regions from the substrate using a second chemistry.

15. The method of claim 1, wherein the developing the first patterned layer further comprises:

performing a positive development procedure to remove one or more of the high exposure regions from the substrate using a first chemistry;

performing at least one additional exposure procedure, thereby creating a new first number of de-protected groups in the high exposure regions, creating a new second number of de-protected groups in the medium exposure regions, and creating a new third number of de-protected groups in the low exposure regions;

determining a second threshold profile for a first negative tone development procedure for the first patterned layer of exposed radiation-sensitive material using at least one of the new first number of de-protected groups in the high exposure regions, the new second number of de-protected groups in the medium exposure regions, and the new third number of de-protected groups in the low exposure regions;

determining a second set of limits for the first negative tone development procedure;

modifying the second threshold profile if the second threshold profile exceeds at least one of the second set of limits; and

performing a negative development procedure to remove one or more of the low exposure regions from the substrate using a second chemistry, if the second threshold profile does not exceed at least one of the second set of limits.

16. A semiconductor processing system for patterning a substrate, comprising:

a lithography system configured to form a layer of radiation-sensitive material on the substrate, wherein the layer of radiation-sensitive material comprises a resist material having a polymer backbone and a plurality of protecting groups;

an exposure system configured to create a first patterned layer of exposed radiation-sensitive material by exposing the layer of radiation-sensitive material using first EM radiation and a reticle having a plurality of masking features, wherein the exposure system is coupled to the lithography system;

wherein the lithography system is configured to heat the first patterned layer of exposed radiation-sensitive material thereby creating a plurality of high exposure regions having a first number of de-protected groups, a plurality of medium exposure regions having a second number of de-protected groups, and a plurality of low exposure regions having a third number of de-protected groups; and

a computer system configured to determine a first threshold profile for a first positive tone development procedure for the first patterned layer of exposed radiation-sensitive material using at least one of the first number of de-protected groups in the high exposure regions, the second number of de-protected groups in the medium exposure regions, and the third number of de-protected groups in the low exposure regions, and configured to determine a first set of limits for a first dual-tone development procedure, the computer system being coupled to the exposure system and the lithography system,

wherein the lithography system is configured to modify the first threshold profile if the first threshold profile exceeds a first limit of the first set of limits, and is further configured to develop the first patterned layer of exposed radiation-sensitive material if the first threshold profile does not exceed the first limit of the first set of limits.

17. A computer readable medium containing program instructions for execution on a computer system coupled to a semiconductor processing system, which when executed by the computer system, cause the semiconductor processing system to perform a process, comprising:

forming a layer of radiation-sensitive material on a substrate, wherein the layer of radiation-sensitive material comprises a resist material having a polymer backbone and a plurality of protecting groups;

creating a first patterned layer of exposed radiation-sensitive material by exposing the layer of radiation-sensitive material using a first EM radiation and a reticle having a plurality of masking features, and heating the first patterned layer of exposed radiation-sensitive material thereby creating a plurality of high exposure regions having a first number of de-protected groups, a plurality of medium exposure regions having a second number of de-protected groups, and a plurality of low exposure regions having a third number of de-protected groups in the low exposure regions;

determining a first threshold profile for a first positive tone development procedure for the first patterned layer of exposed radiation-sensitive material using at least one of the first number of de-protected groups in the high exposure regions, the second number of de-protected groups in the medium exposure regions, and the third number of de-protected groups in the low exposure regions;

determining a first set of limits for a first dual-tone development procedure;

modifying the first threshold profile if the first threshold profile exceeds a first limit of the first set of limits; and

developing the first patterned layer of exposed radiation-sensitive material if the first threshold profile does not exceed the first limit of the first set of limits.

18. A method of patterning a substrate, comprising:

forming a layer of radiation-sensitive material on the substrate, wherein the layer of radiation-sensitive material comprises a resist material having a polymer backbone and a plurality of protecting groups;

creating a first patterned layer of exposed radiation-sensitive material by exposing the layer of radiation-sensitive material using a first EM radiation and a reticle having a plurality of masking features, and heating the first patterned layer of exposed radiation-sensitive material thereby creating a plurality of high exposure regions having a first number of de-protected groups, a plurality of medium exposure regions having a second number of de-protected groups, and a plurality of low exposure regions having a third number of de-protected groups in the low exposure regions;

creating a second patterned layer by developing the first patterned layer of exposed radiation-sensitive material using a first positive tone developing procedure;

determining a negative threshold profile and a negative threshold limit for a negative tone development procedure for the second patterned layer;

establishing a second energy level using the negative threshold profile and the negative threshold limit;

creating a third patterned layer by exposing the second patterned layer to a second EM radiation at the second energy level; and

creating a fourth patterned layer by developing the third patterned layer of using a first negative tone developing procedure.

19. A method of patterning a substrate, comprising:

forming a layer of radiation-sensitive material on the substrate, wherein the layer of radiation-sensitive material comprises a resist material having a polymer backbone and a plurality of protecting groups;

creating a first patterned layer of exposed radiation-sensitive material by exposing the layer of radiation-sensitive material using a first EM radiation and a reticle having a plurality of masking features, and heating the first patterned layer of exposed radiation-sensitive material thereby creating a plurality of high concentration regions having a first number of de-protected groups, a plurality of medium concentration regions having a second number of de-protected groups, and a plurality of low concentration regions having a third number of de-protected groups in the low exposure regions;

determining a first threshold profile for a first positive tone development procedure for the first patterned layer of exposed radiation-sensitive material using at least one of the first number of de-protected groups in the high concentration regions, the second number of de-protected groups in the medium concentration regions, and the third number of de-protected groups in the low concentration regions;

determining a first set of limits for a first dual-tone development procedure;

modifying the first threshold profile if the first threshold profile exceeds a first limit of the first set of limits; and

developing the first patterned layer of exposed radiation-sensitive material if the first threshold profile does not exceed the first limit of the first set of limits.

20. The method of claim 19, wherein the developing the first patterned layer further comprises:

performing a positive development procedure to remove one or more of the high concentration regions from the substrate using a first chemistry;

performing at least one additional exposure procedure, thereby creating a new first number of de-protected groups in the high concentration regions, creating a new second number of de-protected groups in the medium concentration regions, and creating a new third number of de-protected groups in the low concentration regions;

determining a second threshold profile for a first negative tone development procedure for the first patterned layer using at least one of the new first number of de-protected groups in the high concentration regions, the new second number of de-protected groups in the medium concentration regions, and the new third number of de-protected groups in the low concentration regions;

determining a second set of limits for the first negative tone development procedure;

modifying the second threshold profile if the second threshold profile exceeds at least one of the second set of limits; and

performing a negative development procedure to remove one or more of the low concentration regions from the substrate using a second chemistry, if the second threshold profile does not exceed at least one of the second set of limits.