Method and apparatus for dynamic lithographic exposure

Patent metadata

Field	Value
Publication number	US-11003089-B2
Application number	US-202016850285-A
Country	US
Kind code	B2
Filing date	Apr 16, 2020
Priority date	Jan 27, 2016
Publication date	May 11, 2021
Grant date	May 11, 2021

Abstract

The present disclosure, in some embodiments, relates to a method of performing a photolithography process. The method includes forming a photosensitive material over a substantially flat upper surface of a substrate. The substantially flat upper surface of the substrate extends between opposing sides of the substrate. The photosensitive material is exposed to electromagnetic radiation at a plurality of depths of focus that are centered at different heights over the substrate. The photosensitive material is developed to remove a part of the photosensitive material.

First claim

What is claimed is:

1. A method of performing a photolithography process, comprising:
forming a photosensitive material over a substantially flat upper surface of a substrate, wherein the substantially flat upper surface of the substrate extends between opposing sides of the substrate;
exposing the photosensitive material to electromagnetic radiation at a plurality of depths of focus that are centered at different heights over the substrate; and
developing the photosensitive material to remove a part of the photosensitive material.

2. The method of claim 1 , wherein the photosensitive material is continuously exposed to the electromagnetic radiation while a distance between a source of the electromagnetic radiation and the substrate changes.

3. The method of claim 1 , wherein at least two of the plurality of depths of focus vertically overlap.

4. The method of claim 1 , wherein the plurality of depths of focus comprise a first depth of focus centered at a first point over the substrate and a second depth of focus centered at a second point directly over the first point.

5. The method of claim 1 , wherein the electromagnetic radiation exposes the photosensitive material to a same pattern at each of the plurality of depths of focus.

6. The method of claim 1 , wherein the plurality of depths of focus collectively expose the photosensitive material over a cumulative depth of focus that is larger than any one of the plurality of depths of focus.

7. The method of claim 1 , wherein the plurality of depths of focus continuously extend between an upper surface of the photosensitive material and a lower surface of the photosensitive material.

8. A method of performing a photolithography process, comprising:
focusing electromagnetic radiation over a first depth of focus at a first time, wherein the first depth of focus is centered at a first depth below an upper surface of a photosensitive material over a substrate;
focusing the electromagnetic radiation over a second depth of focus at a second time, wherein the second depth of focus is centered at a second depth below the upper surface of the photosensitive material; and
wherein the second depth of focus vertically overlaps the first depth of focus.

9. The method of claim 8 , wherein the photosensitive material is exposed to separate bursts of electromagnetic radiation at the first time and at the second time.

10. The method of claim 8 , wherein the first depth of focus and the second depth of focus collectively span a larger vertical distance than the first depth of focus or the second depth of focus.

11. The method of claim 8 , wherein the first depth of focus and the second depth of focus collectively define a cumulative depth of focus that has a first process window that is larger than a second process window provided by either the first depth of focus or the second depth of focus.

12. The method of claim 8 , wherein the first depth of focus and the second depth of focus collectively define a cumulative depth of focus that has a first process window that is over 30% larger than a second process window provided by either the first depth of focus or the second depth of focus.

13. The method of claim 8 , wherein a point within the photosensitive material receives a first dose of the electromagnetic radiation over both the first time and the second time that is greater than a second dose of the electromagnetic radiation that the point receives at either the first time or the second time.

14. The method of claim 8 ,
wherein the first depth of focus has a largest dose at a first height over the substrate and the second depth of focus has a largest dose at a second height over the substrate; and
wherein the first depth of focus and the second depth of focus provide for a collective depth of focus having a largest dose at a point that is vertically between the first height and the second height.

15. The method of claim 8 ,
wherein the electromagnetic radiation is focused at the first time along a first path that converges at a first point; and
wherein the electromagnetic radiation is focused at the second time along a second path that converges at a second point that is directly above the first point.

16. A method of performing a photolithography process, comprising:
forming a photosensitive material over a substrate; and
exposing the photosensitive material to electromagnetic radiation, wherein the photosensitive material is continuously exposed to the electromagnetic radiation while a focus of the electromagnetic radiation moves along a vertical direction that is perpendicular to an upper surface of the photosensitive material.

17. The method of claim 16 , wherein the electromagnetic radiation exposes the photosensitive material to a same pattern while the focus of the electromagnetic radiation moves along the vertical direction.

18. The method of claim 16 , wherein the focus of the electromagnetic radiation moves so as to monotonically increase a depth of an image plane of the electromagnetic radiation within the photosensitive material.

19. The method of claim 16 , further comprising:
changing a location of a stage configured to hold the substrate while continuously exposing the photosensitive material to the electromagnetic radiation.

20. The method of claim 16 ,
wherein the electromagnetic radiation is focused at a first time along a first path that converges at a first point over the substrate; and
wherein the electromagnetic radiation is focused at a second time along a second path that converges at a second point that is directly above the first point.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Yu Jun-Yih
• Huang De-Fang
• Tseng De-Chen
• Chang jia-feng
• Hsu Li-Fang

Classifications

• G03F7/70333 Primary

  Focus drilling, i.e. increase in depth of focus for exposure by modulating focus during exposure [FLEX] · CPC title

• G03F7/70641

  Focus · CPC title

• G03F7/203 Primary

  comprising an imagewise exposure to electromagnetic radiation or corpuscular radiation · CPC title

• G03F7/063

  Additives or means to improve the lithographic properties; Processing solutions characterised by such additives; Treatment after development or transfer, e.g. finishing, washing; Correction or deletion fluids · CPC title

• G03F7/26

  Processing photosensitive materials; Apparatus therefor (G03F7/12 - G03F7/24 take precedence) · CPC title