Lithographic Resist With Floating Protectant

Patent metadata

Field	Value
Publication number	US-2016254142-A1
Application number	US-201514632793-A
Country	US
Kind code	A1
Filing date	Feb 26, 2015
Priority date	Feb 26, 2015
Publication date	Sep 1, 2016
Grant date	—

Abstract

An improved resist material and a technique for patterning a workpiece such as an integrated circuit workpiece that offers improved resistance to environmental contaminants is provided. In an exemplary embodiment, the method includes receiving a workpiece and applying to the workpiece a resist material containing a protectant disbursed throughout. A thermal process is performed on the workpiece that causes the protectant to become concentrated in an upper region of the resist material. The resist material is exposed in a lithographic process and the exposed resist material is developed to define a pattern within the resist material. In some such examples, the protectant is selected to reduce an effect of an environmental contaminant without affecting an acid/base ratio of the resist material. In some such embodiments, the protectant includes a hydrophobic functional group.

First claim

What is claimed is:

1 . A fabrication method comprising:
receiving a workpiece; applying, to the workpiece, a resist material containing a protectant disbursed throughout; performing a thermal process on the workpiece, the thermal process configured to cause the protectant to become concentrated in an upper region of the resist material; exposing the resist material in a lithographic process; developing the exposed resist material to define a pattern within the resist material; and selectively processing a portion of the workpiece based on the pattern of the resist material.

2 . The fabrication method of claim 1 further comprising:
performing a settling process on the workpiece, wherein the settling process is configured to cause the protectant to become concentrated in the upper region of the resist material.

3 . The fabrication method of claim 1 , wherein the protectant is selected to reduce an effect of an environmental contaminant without affecting an acid/base ratio of the resist material.

4 . The fabrication method of claim 1 , wherein the protectant includes a hydrophobic functional group.

5 . The fabrication method of claim 1 , wherein the protectant includes least one of:
an aromatic carbon ring, an alkene functional group, or an alkyne functional group.

6 . The fabrication method of claim 1 , wherein the protectant includes a polymer chain of the form:

where each of R 1 and R 2 includes one of: an aromatic carbon ring, an alkene group, an alkyne group, an alkyl group, an alkoxyl group, a fluoroalkyl group, a fluoroalkoxyl group, an epoxyl group, an amine group, a halide, —H, —OH, —Cl, —Br, —I, —NO 2 , —SO 3 , —CN, —NCO, —OCN, —CO 2 , —COOH, or —OH.

7 . The fabrication method of claim 1 , wherein the protectant includes a polymer chain of the form:

where each of R 1 and R 2 includes at least one group of the form: —OR*, —OC(O)CR*, —SR*, —SO 2 N(R*) 2 , —SO 2 R*, —SOR*, —OC(O)R*, —C(O)OR*, —C(O)R*, —Si(OR*) 3 , or —Si(R*) 3 and where R* is one of: H, an alkyl group, an alkenyl group, or an alkynyl group.

8 . The fabrication method of claim 1 , wherein the protectant is selected such that at least one of: a molecular weight difference, a polarity difference, a water affinity difference, a difference in solubility in a solvent of the resist material, or a difference in solubility in a polymer of the resist material causes the protectant to become concentrated in the upper region of the resist material.

9 . The fabrication method of claim 1 , wherein the protectant has a molecular weight between about 1000 and about 3000.

10 . A lithographic method comprising:
receiving a substrate; applying a resist containing a protectant to the substrate, wherein a top region of the resist opposite the substrate has a first concentration of the protectant after applying the resist; thereafter, performing a process operable to increase a concentration of the protectant in the top region from the first concentration to a second concentration; performing a lithographic exposure of the resist to define a pattern therein; and processing a portion of the substrate using the pattern defined in the exposed resist.

11 . The lithographic method of claim 10 , wherein the process operable to increase the concentration of the protectant includes:
performing a prebake of the substrate having the resist applied thereupon.

12 . The lithographic method of claim 11 , wherein the process operable to increase the concentration of the protectant further includes:
maintaining the substrate having the resist applied thereupon at a temperature lower than a temperature of the prebake for a predetermined period of time.

13 . The lithographic method of claim 12 , wherein the predetermined period of time is at least one hour.

14 . The lithographic method of claim 10 , wherein the protectant includes a hydrophobic functional group.

15 . The lithographic method of claim 10 , wherein the protectant includes least one of: an aromatic carbon ring, an alkene functional group, or an alkyne functional group.

16 . The lithographic method of claim 10 , wherein the protectant is selected such that at least one of: a molecular weight difference, a polarity difference, a water affinity difference, a difference in solubility in a solvent of the resist, or a difference in solubility in a polymer of the resist causes the protectant to become concentrated in the top region of the resist.

17 . The lithographic method of claim 10 , wherein the protectant includes a polymer chain of the form:

where each of R 1 and R 2 includes one of: an aromatic carbon ring, an alkene group, an alkyne group, an alkyl group, an alkoxyl group, a fluoroalkyl group, a fluoroalkoxyl group, an epoxyl group, an amine group, a halide, —H, —OH, —Cl, —Br, —I, —NO 2 , —SO 3 , —CN, —NCO, —OCN, —CO 2 , —COOH, or —OH.

18 . A lithographic resist material comprising:
a photosensitive material; a polymer; and a protectant configured to increase in concentration at a topmost region of the lithographic resist material after application.

19 . The lithographic resist material of claim 18 , wherein the protectant includes a polymer chain of the form:

where each of R 1 and R 2 includes one of: an aromatic carbon ring, an alkene group, an alkyne group, an alkyl group, an alkoxyl group, a fluoroalkyl group, a fluoroalkoxyl group, an epoxyl group, an amine group, a halide, —H, —OH, —Cl, —Br, —I, —NO 2 , —SO 3 , —CN, —NCO, —OCN, —CO 2 , —COOH, or —OH.

20 . The lithographic resist material of claim 18 , wherein the protectant includes a polymer chain of the form:

where each of R 1 and R 2 includes at least one group of the form: —OR*, —OC(O)CR*, —SR*, —SO 2 N(R*) 2 , —SO 2 R*, —SOR*, —OC(O)R*, —C(O)OR*, —C(O)R*, —Si(OR*) 3 , or —Si(R*) 3 and where R* is one of: H, an alkyl group, an alkenyl group, or an alkynyl group.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Chang Ching-Yu
• Wang Chien-Wei
• Chen Hsueh-An

Classifications

• H10P76/2041

  Photolithographic processes · CPC title

• H10P50/692

  characterised by their composition, e.g. multilayer masks or materials · CPC title

• G03F7/11 Primary

  having cover layers or intermediate layers, e.g. subbing layers {(G03F7/091 - G03F7/093, B41N3/03 take precedence)} · CPC title

• G03F7/20

  Exposure; Apparatus therefor (photographic printing apparatus for making copies G03B27/00) · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title