Acoustic Measurement of Fabrication Equipment Clearance

Patent metadata

Field	Value
Publication number	US-2021072196-A1
Application number	US-202017102255-A
Country	US
Kind code	A1
Filing date	Nov 23, 2020
Priority date	Nov 16, 2015
Publication date	Mar 11, 2021
Grant date	—

Abstract

Methods and systems disclosed herein use acoustic energy to determine a gap between a wafer and an integrated circuit (IC) processing system and/or determine a thickness of a material layer of the wafer during IC processing implemented by the IC processing system. An exemplary method includes emitting acoustic energy through a substrate and a material layer disposed thereover. The substrate is positioned within an IC processing system. The method further includes receiving reflected acoustic energy from a surface of the substrate and a surface of the material layer disposed thereover and converting the reflected acoustic energy into electrical signals. The electrical signals indicate a thickness of the material layer.

First claim

What is claimed is:

1 . A method comprising:
delivering, by a nozzle, a fluid to a substrate; when a tip of the nozzle from which the fluid is delivered to the substrate is aligned with an acoustic transducer at a first time during the delivering of the fluid to the substrate, measuring a first width of a first gap between the substrate and the tip of the nozzle, wherein the measuring is based on first reflected acoustic energy received by the acoustic transducer from the substrate and the tip of the nozzle and the acoustic transducer is physically separate from the nozzle; when the tip of the nozzle from which the fluid is delivered to the substrate is aligned with the acoustic transducer at a second time during the delivering of the fluid to the substrate, measuring a second width of a second gap between the substrate and the tip of the nozzle, wherein the measuring is based on second reflected acoustic energy received by the acoustic transducer from the substrate and the tip of the nozzle; and determining whether to adjust an alignment between the substrate and the tip of the nozzle based on the first width of the first gap at the first time and the second width of the second gap at the second time, wherein the alignment prevents physical contact between the nozzle and the substrate.

2 . The method of claim 1 , wherein the first time corresponds with the tip of the nozzle delivering the fluid to a first location of the substrate and the second time corresponds with the tip of the nozzle delivering the fluid to a second location of the substrate.

3 . The method of claim 1 , wherein the first time corresponds with a first rotation of the substrate, the second time corresponds with a second rotation of the substrate, and the first time and the second time correspond with the tip of the nozzle delivering the fluid to the same location.

4 . The method of claim 1 , further comprising moving the acoustic transducer to align the tip of the nozzle and the acoustic transducer.

5 . The method of claim 1 , wherein the substrate is positioned between the nozzle and the acoustic transducer, such that the nozzle is positioned along and delivers the fluid to a first surface of the substrate and the acoustic transducer is positioned along a second surface of the substrate, wherein the second surface of the substrate is opposite the first surface of the substrate.

6 . The method of claim 1 , wherein:
the substrate is retained and rotated within a process chamber by a rotating chuck; the acoustic transducer includes a transducer layer, a damping backing material layer, and an acoustic impedance matching layer, wherein the damping backing material layer is disposed between the transducer layer and the acoustic impedance matching layer; and the rotating chuck is not disposed between the acoustic impedance matching layer of the acoustic transducer and the substrate.

7 . The method of claim 6 , wherein the fluid is gas and the first gap and the second gap are filled with the gas at the first time and the second time, respectively.

8 . The method of claim 1 , wherein the substrate is a reflective mask and the fluid is a cleaning solution for cleaning a surface of the reflective mask.

9 . A method comprising:
receiving a substrate in an integrated circuit (IC) processing system, wherein the IC processing system includes a nozzle for delivering a fluid to the substrate during an IC process; during the IC process:
aligning an acoustic transducer with a first gap between the substrate and the nozzle at a first location and using the acoustic transducer to measure a first width of the first gap at the first location;
aligning the acoustic transducer with a second gap between the substrate and the nozzle at a second location and using the acoustic transducer to measure a second width of the second gap at the second location; and
controlling a clearance between the substrate and the nozzle based on the first width of the first gap at the first location and the second width of the second gap at the second location, such that the nozzle does not physically contact the substrate.

10 . The method of claim 9 , wherein the controlling the clearance between the substrate and the nozzle based on the first width of the first gap and the second width of the second gap includes determining whether a substrate surface and a nozzle surface are parallel.

11 . The method of claim 9 , wherein the controlling the clearance between the substrate and the nozzle based on the first width of the first gap and the second width of the second gap includes detecting substrate tilt and adjusting the substrate, the nozzle, or both to prevent physical contact between the nozzle and the substrate.

12 . The method of claim 9 , wherein the controlling the clearance between the substrate and the nozzle based on the first width of the first gap and the second width of the second gap includes detecting substrate surface irregularities and adjusting the substrate, the nozzle, or both to prevent physical contact between the nozzle and the substrate to prevent physical contact between the nozzle and the substrate.

13 . The method of claim 9 , wherein the controlling the clearance between the substrate and the nozzle based on the first width of the first gap and the second width of the second gap includes detecting substrate misalignment and adjusting the substrate, the nozzle, or both to prevent physical contact between the nozzle and the substrate.

14 . The method of claim 9 , wherein the aligning the acoustic transducer includes aligning the acoustic transducer directly underneath the first gap and the second gap, respectively.

15 . The method of claim 9 , wherein the aligning the acoustic transducer includes moving the acoustic transducer along an armature of the IC processing system.

16 . The method of claim 9 , wherein the nozzle delivers the fluid to a topside surface of the substrate, the acoustic transducer is disposed along a backside surface of the substrate, and a chuck of the IC processing system is not disposed between the acoustic transducer and the backside surface of the substrate.

17 . A system comprising:
a chuck operable to retain a wafer in the system, wherein a gap is defined between the wafer and the system; a transducer operable to:
emit acoustic energy through the wafer,
receive reflected acoustic energy from the wafer and the system, and
convert the reflected acoustic energy into electrical signals; and
a signal processor coupled to the transducer, wherein the signal processor is operable to receive the electrical signals and determine a width of the gap.

18 . The system of claim 17 , further comprising an impedance matching layer disposed between the transducer and the wafer, wherein the impedance matching layer has impedance between that of the transducer and that of the wafer.

19 . The system of claim 17 , wherein the electrical signals identify a first order echo response from the wafer and a first order echo response from the system, and the signal processor is operable to determine the width based on a time at which the first order echo response from the wafer is received and a time at which the first order echo response from the system is received.

20 . The system of claim 17 , further comprising an armature coupled to the transducer, wherein the armature is operable to align the transducer with the gap.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Deng jun-hao
• Lin Kuan-Wen
• Chin Sheng-Chi
• Lee Yu-Ching

Classifications

• H10P74/20

  characterised by the properties tested or measured, e.g. structural or electrical properties · CPC title

• H10P72/0604

  Process monitoring, e.g. flow or thickness monitoring · CPC title

• H10P70/00

  Cleaning of wafers, substrates or parts of devices · CPC title

• H10P14/6342

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

• H10P14/46

  using a liquid · CPC title