Pellicle aging estimation and particle removal from pellicle via acoustic waves

Patent metadata

Field	Value
Publication number	US-2016274471-A1
Application number	US-201514658399-A
Country	US
Kind code	A1
Filing date	Mar 16, 2015
Priority date	Mar 16, 2015
Publication date	Sep 22, 2016
Grant date	—

Abstract

A pellicle is disposed over a lithography mask. An acoustic wave generator is placed over the pellicle. The acoustic wave generator is configured to generate acoustic waves to cause the pellicle to vibrate at a target resonance frequency. A resonance detection tool is configured to detect an actual resonance frequency of the pellicle in response to the acoustic waves. One or more electronic processors are configured to estimate an age condition of the pellicle as a function of a shift of the actual resonance frequency from the target resonance frequency.

First claim

What is claimed is:

1 . A system, comprising:
a pellicle disposed over a lithography mask; an acoustic wave generator placed over the pellicle, wherein the acoustic wave generator is configured to generate acoustic waves to cause the pellicle to vibrate at a target resonance frequency; a resonance detection tool configured to detect an actual resonance frequency of the pellicle in response to the acoustic waves; and one or more electronic processors configured to estimate an age condition of the pellicle as a function of a shift of the actual resonance frequency from the target resonance frequency.

2 . The system of claim 1 , wherein the acoustic wave generator includes a microphone or an array acoustic transducer that includes a plurality of acoustic transducers.

3 . The system of claim 1 , wherein the acoustic wave generator is configured to generate the acoustic waves to force the pellicle to vibrate at a predetermined mode of oscillation.

4 . The system of claim 1 , wherein the resonance detection tool includes:
a source located on a first side of the pellicle, the source being configured to generate a signal that travels across the pellicle; and a sensor located on a second side of the pellicle opposite the first side, the sensor being configured to receive the signal.

5 . The system of claim 4 , wherein the source includes a laser, and wherein the sensor includes a photo receiver.

6 . The system of claim 4 , wherein the source includes a light, and wherein the sensor includes a charge-coupled device (CCD).

7 . The system of claim 1 , wherein the resonance detection tool includes a Laser Doppler Interferometer.

8 . The system of claim 1 , wherein the acoustic waves are first acoustic waves, and wherein the acoustic wave generator is further configured to generate second acoustic waves for removing contaminant particles located on the pellicle.

9 . A method, comprising:
applying acoustic waves toward a pellicle that is disposed over a lithography mask to cause the pellicle to vibrate at a target resonance frequency; detecting an actual resonance frequency of the pellicle in response to the acoustic waves; and estimating an age condition of the pellicle as a function of a shift of the actual resonance frequency from the target resonance frequency.

10 . The method of claim 9 , wherein the applying comprises generating the acoustic waves via an array acoustic transducer or a microphone.

11 . The method of claim 9 , wherein the applying comprises forcing the pellicle to vibrate at a predetermined mode of oscillation.

12 . The method of claim 9 , wherein the detecting comprises:
generating, via a source located on a first side of the pellicle, a signal that travels across the pellicle; receiving the signal via a sensor located on a second side of the pellicle opposite the first side; and detecting the actual resonance frequency based on the received signal.

13 . The method of claim 12 , wherein the source includes a laser, and wherein the sensor includes a photo receiver.

14 . The method of claim 12 , wherein the source includes a light, and wherein the sensor includes a charge-coupled device (CCD).

15 . The method of claim 9 , wherein the detecting comprises detecting the actual resonance frequency via a Laser Doppler Interferometer.

16 . The method of claim 9 , wherein the acoustic waves are first acoustic waves, and further comprising applying second acoustic waves toward the pellicle to remove contaminant particles located on the pellicle.

17 . A system, comprising:
a pellicle disposed over a lithography mask; an acoustic transducer disposed over a first end portion of the pellicle; an acoustic receiver disposed over a second end portion of the pellicle opposite the first end portion; and one or more electronic processors; wherein: the acoustic transducer is configured to generate an acoustic signal that propagates as a traveling wave from the first end portion toward the second end portion; the acoustic receiver is configured to receive the acoustic signal; and the one or more electronic processors are configured to estimate an age condition of the pellicle by calculating a Young's modulus based on the received acoustic signal.

18 . The system of claim 17 , wherein the one or more electronic processors are configured to estimate the age condition of the pellicle by ascertaining whether a logarithmic value of the Young's modulus falls within a glassy region, a glass transition region, a rubbery plateau region, or a rubbery flow region.

19 . The system of claim 17 , further comprising a frequency sweep generator coupled to the acoustic transducer, wherein the frequency sweep generator is configured to cause the pellicle to vibrate at a plurality of oscillation modes.

20 . The system of claim 19 , wherein the plurality of oscillation modes are configured to remove contaminant particles located on the pellicle.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Lee Yu-Ching
• Yu Ching-Fang
• Lin Chun-Hung
• Chin Sheng-Chi
• Hsu Ting-Hao
• Chang Mark

Classifications

• G03F7/70591 Primary

  Testing optical components · CPC title

• G03F1/62 Primary

  Pellicles, e.g. pellicle assemblies, e.g. having membrane on support frame; Preparation thereof · CPC title

• H04R9/08

  Microphones · CPC title

• H04R9/06

  Loudspeakers · CPC title

• G03F7/70983

  Optical system protection, e.g. pellicles or removable covers for protection of mask · CPC title