Extreme ultraviolet (EUV) lithography using an intervening layer or a multi-layer stack with varying mean free paths for secondary electron generation

Patent metadata

Field	Value
Publication number	US-12372872-B2
Application number	US-202017595062-A
Country	US
Kind code	B2
Filing date	May 15, 2020
Priority date	May 16, 2019
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

A method for patterning a substrate includes providing a substrate, and depositing a multi-layer stack including N layers on the substrate. N is an integer greater than one. The N layers include N mean free paths for secondary electrons, respectively. The method includes depositing a photoresist layer on the multi-layer stack, wherein the N mean free paths converge in the photoresist layer. Another method for patterning a substrate includes providing a substrate and depositing a layer on the substrate. The layer includes varying mean free paths for secondary electrons. The method includes depositing a photoresist layer on the layer. The varying mean free paths for secondary electrons converge in the photoresist layer.

First claim

What is claimed is:

1. A method for patterning a substrate, comprising:
depositing a first layer on a substrate, the first layer comprising Si or SiON and having a first thickness of 3 nm or 6 nm, wherein the first layer includes a first mean free path for secondary electrons;
depositing a second layer on the first layer, the second layer comprising Sn or SnO2 and having a second thickness, wherein the second thickness is 2 nm or 4 nm when the first thickness is 3 nm or 6 nm, respectively, and wherein the second layer includes a second mean free path for secondary electrons that is lower than the first mean free path; and
depositing a photoresist layer on the second layer, the photoresist layer comprising chemically amplified organic photoresist material, wherein the first and second mean free paths converge in the photoresist layer.

2. The method of claim 1 , wherein the first and second mean free paths of the first and second layers are different.

3. The method of claim 1 , wherein the first and second layers are located at first and second distances from the photoresist layer, respectively; and wherein the first and second mean free paths of the first and second N-layers increase proportionally with the first and second distances.

4. The method of claim 1 , wherein the first and second layers are located at first and second distances from the photoresist layer, respectively; and wherein the first and second mean free paths of the first and second layers monotonically increase according to the first and second distances.

5. The method of claim 1 , wherein the first and second layers are located at first and second distances from the photoresist layer, respectively; and wherein the first and second mean free paths of the first and second layers linearly increase according to the first and second distances.

6. The method of claim 1 , wherein the first and second layers are located at first and second distances from the photoresist layer, respectively, and have first and second absorption rates, respectively; and wherein the first and second absorption rates of the first and second layers, respectively, increase as according to the first and second distances.

7. The method of claim 1 , wherein each layer of the first and second layers has the same thickness.

8. The method of claim 1 , wherein each layer of the first and second layers has a different thickness.

9. The method of claim 8 further comprising arranging the first and second layers in an increasing order of thickness, with a thinner layer of the first and second layers arranged adjacent to the photoresist layer and with a thicker layer of the first and second layers arranged adjacent to the substrate.

10. The method of claim 1 further comprising exposing the photoresist layer to extreme ultraviolet radiation.

11. The method of claim 1 further comprising:
exposing the photoresist layer to extreme ultraviolet radiation;
removing exposed portions of the photoresist layer; and
removing portions of the multi-layer stack located in areas where the photoresist layer is removed.

12. The method of claim 1 further comprising:
exposing the photoresist layer to extreme ultraviolet radiation;
removing exposed portions of the photoresist layer to form a patterned photoresist layer;
performing a deposition process using the patterned photoresist layer; and
removing the photoresist layer and the multi-layer stack after performing the deposition process.

13. The method of claim 1 further comprising:
exposing the photoresist layer to extreme ultraviolet radiation;
removing exposed portions of the photoresist layer to form a patterned photoresist layer;
performing an etching process using the patterned photoresist layer; and
removing the photoresist layer and the multi-layer stack after performing the etching process.

Assignees

• Lam Res Corp

Inventors

• Liang Andrew
• Shamma Nader
• Wise Rich
• Singhal Akhil
• Mahorowala Arpan Pravin
• Blachut Gregory
• Austin Dustin Zachary

Classifications

• H10P76/2045

  Electron beam lithography processes · CPC title

• G03F7/70033 Primary

  by plasma extreme ultraviolet [EUV] sources · CPC title

• G03F7/115

  having supports or layers with means for obtaining a screen effect or for obtaining better contact in vacuum printing · CPC title

• G03F7/09

  characterised by structural details, e.g. supports, auxiliary layers (supports for printing plates in general B41N) · CPC title

• G03F7/2004 Primary

  characterised by the use of a particular light source, e.g. fluorescent lamps or deep UV light · CPC title