Patterning process with silicon mask layer

Patent metadata

Field	Value
Publication number	US-10115592-B2
Application number	US-201715595525-A
Country	US
Kind code	B2
Filing date	May 15, 2017
Priority date	Dec 15, 2016
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

A lithography method is provided in accordance with some embodiments. The lithography method includes forming an under layer on a substrate; forming a silicon-containing middle layer on the under layer, wherein the silicon-containing middle layer has a thermal base generator (TBG) composite; forming a photosensitive layer on the silicon-containing middle layer; performing an exposing process to the photosensitive layer; and developing the photosensitive layer, thereby forming a patterned photosensitive layer.

First claim

What is claimed is:

1. A lithography method, comprising:
forming an under layer on a substrate;
forming a silicon-containing middle layer on the under layer, wherein the silicon-containing layer includes a type of monomers that each has four cross-linkable sides, and wherein the silicon-containing middle layer has a thermal base generator (TBG) composite that is capable of releasing a base;
forming a photosensitive layer on the silicon-containing middle layer;
performing an exposing process to the photosensitive layer; and
developing the photosensitive layer, thereby forming a patterned photosensitive layer.

2. The method of claim 1 , further comprising:
performing a thermal treatment to the silicon-containing middle layer, wherein during the thermal treatment the TB G composite evaporates from the silicon-containing middle layer after releasing the base from the TBG composite.

3. The method of claim 2 , wherein the thermal treatment is a baking process comprising a first baking step that heats the silicon-containing middle layer at a first temperature and a second baking step that heats the silicon-containing middle layer at a second temperature higher than the first temperature, and wherein the first temperature is higher than a triggering temperature for the TBG composite to release the base and the second temperature is higher than a boiling temperature of the TBG composite.

4. The method of claim 2 , wherein a molecular weight of polymers in the silicon-containing middle layer is smaller than 5,000 g/mol before the thermal treatment and greater than 10,000 g/mol after the thermal treatment.

5. The method of claim 2 , wherein the performing of the thermal treatment is in-situ with the forming of the silicon-containing middle layer.

6. The method of claim 1 , wherein the TBG composite has a molecular weight of less than 300 g/mol.

7. The method of claim 6 , wherein the TBG composite includes a chemical structure selected from a group of

8. The method of claim 1 , wherein the TBG composite has a molecular weight of less than 200 g/mol.

9. The method of claim 8 , wherein the TBG composite includes a chemical structure as

10. The method of claim 1 , wherein a percentage of the type of monomers over a total number of monomers in the silicon-containing middle layer is greater than 40%.

11. The method of claim 1 , wherein the silicon-containing middle layer includes siloxane polymer with a chemical structure as

wherein O and Si represent oxygen and silicon, respectively;
a, b, and c represent weight percentages of X, R, and D groups, respectively;
X represents a first organic group that provides cross-linking sites;
R represents a second organic group that enhances etching resistance, adhesion of the photosensitive layer; and
D represents an aromatic group designed to tune extinction coefficient and index of refraction.

12. The method of claim 1 , further comprising:
performing a first etching process to transfer a pattern of the patterned photosensitive layer to the silicon-containing middle layer;
performing a second etching process to transfer the pattern to the under layer; and
performing a wet cleaning process to remove the silicon-containing middle layer and the under layer, wherein the wet cleaning process includes applying a solution formed by mixing tetramethyl ammonium hydroxide (TMAH) with propylene glycol ethyl ether (PGEE), wherein the solution has a pH value greater than a pH value of the silicon-containing middle layer.

13. A method for lithography patterning, comprising:
forming an under layer on a substrate, wherein the under layer contains carbon;
forming a middle material on the under layer, wherein the middle material has a substantially uniform composition, and wherein the middle material includes silicon-containing monomers and a thermal base generator (TBG) additive;
performing a heating process to the middle material, wherein the heating process drives the TBG additive out of the middle material, thereby forming a middle layer containing siloxane polymers;
forming a photosensitive layer on the middle layer; and
developing the photosensitive layer, thereby forming a patterned photosensitive layer.

14. The method of claim 13 , wherein during the performing of the heating process, the TBG additive decomposes into a TBG residual and a base, wherein the TBG residual evaporate thereafter.

15. The method of claim 14 , wherein after the performing of the heating process the middle material shrinks about 20% in volume.

16. The method of claim 14 , wherein the TBG additive has a molecular weight of less than 300 g/mol.

17. The method of claim 14 , wherein the performing of the heating process is in-situ with the forming of the middle material.

18. A method for lithography patterning, comprising:
coating a bottom layer on a substrate, wherein the bottom layer contains carbon;
coating a resin solution on the bottom layer, wherein the resin solution includes a thermal base generator (TBG) composite and monomers that contain silicon;
baking the resin solution to increase both silicon concentration and material density of the resin solution, thereby forming a middle layer, wherein during the baking of the resin solution the TBG composite evaporates from the resin solution after releasing a base, wherein the baking of the resin solution includes baking the resin solution to a first temperature to decompose the TBG composite and then baking the resin solution to a second temperature to evaporate the TBG composite, wherein the second temperature is higher than the first temperature;
forming a patterned photosensitive layer on the middle layer;
performing a first etching process to transfer a pattern of the patterned photosensitive layer to the middle layer;
performing a second etching process to transfer the pattern to the bottom layer; and
performing a wet cleaning process to remove the middle layer and the bottom layer.

19. The method of claim 18 , wherein the TBG composite has a chemical structure selected from a group of

20. The method of claim 18 , wherein the TBG composite has a molecular weight of less than 300 g/mol.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Liu Chen-Yu
• Chang Ching-Yu
• Lin Chin-Hsiang

Classifications

• H10P14/6922

  the material containing Si, O and at least one of H, N, C, F or other non-metal elements, e.g. SiOC, SiOC:H or SiONC · CPC title

• H10P14/6686

  the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane · CPC title

• H10P14/6342

  Liquid deposition, e.g. spin-coating, sol-gel techniques or spray coating · CPC title

• H10P76/405

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

• H10P76/202

  for lift-off processes · CPC title