© 2013 TriQuint Semiconductor, Inc. Automation of RGAs and Sensors for FDC of PVD Metal Thin Film Processing Arif Choudhury 1, Eric McCormick 1, Guy Takayesu.

© 2013 TriQuint Semiconductor, Inc. 

Automation of RGAs and Sensors for FDC of PVD Metal Thin Film Processing

Arif Choudhury1, Eric McCormick1, Guy Takayesu1, Keith Han3, Alex Lee3, Young Hwan Lee3, Justin Wong2, and John Yoo2

1TriQuint Semiconductor Corporation, 500 W Renner Rd, Richardson, Texas, USA 750802BISTel America, 4633 Old Ironsides Dr, Suite 300, Santa Clara, CA 950543BISTel Inc. 2F, Jeongpung Bldg, 1341-3 Seocho-dong, Seocho-gu, Seoul, Korea 137-070

Content

• Introduction– RGA Usage In PVD Process

• Applications of RGA in Manufacturing• Architecture of FDC and Sensors• RGA Filament Control Schemes• Examples of FDC with RGA• Future Work• Conclusion

© 2013 TriQuint Semiconductor, Inc. 

Introduction of RGA and RGA Usage in PVD

• The RGA is commonly used to identify atomic and molecular species in a high vacuum environment.

• In the PVD process the RGA is commonly used to monitor contamination before and during the process.– Screens the incoming substrate for resist residue– Monitoring process gases

• The RGA is very sensitive, it can detect low pressure contaminants in 10-14 Torr

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Pressure Range of PVD Process

• Various Vacuum Mediums*

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*http://www.eng.tau.ac.il/~yosish/courses/vlsi.html

RGA Advantage

• The RGA is an ideal tool for monitoring of PVD process because it can detect subtle changes in the chamber condition, i.e. contamination

• The mean free path increases at high vacuum so the probability of detecting a contaminant goes up.

• Can report the probable species of molecule present in the PVD chamber.

• Possible real time detection of contaminants or chamber leaks.

• Not reliant on metrology feedback.

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Applications of RGA in Manufacturing

• Baseline Spectrum– Spectrum scan of a known good chamber or condition

• Spectrum Analysis (Troubleshooting)– Analyzing the species that exist inside a chamber that is

having some unknown issue• He Leak Checking

– Standard practice after a PVD target change• Stand Alone Process Analysis

– The RGA manufacturers offer stand alone packages for near real time analysis of spectrum as the tool is running.

– Typically not integrated into the house FDC system.– High cost for the software.

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Benefits of Integrating RGA with FDC

Having one system that can connect to multiple components and interdict in the event of an incident saves the expense of having multiple FDC systems for each component Adding RGAs from different manufacturers that are not supported by the tool OEMs.

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Architecture of FDC and Sensors

Y-TAP

PVD Controller

FDC

RGAApplication

RF Application

PumpApplication

RGA Control Libraries

RF Data Collection

Library

Pump Data Collection

Library

PumpPump PM1

PM2

PM3 PM4

PM5

PM6

RF

RGA

RGA

RG

A RG

A

RGA

RGA

Chamber Processing Status

• Wafer Processing Status of Each Chamber•Trace Data

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Component Connections

• Tool SVIDs HSMS Ethernet

• RF Monitor A to D device to receive the analog signals and pass them to the Ethernet

• Pump data RS-232 hub to Ethernet convertor

• Others?

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What is Gained?

• Context for sensors that are not available on processing chambers.

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RGA Filament Control Schemes

• RGA operation constraint– Open Ion Source mode of RGA operation– RGA operating pressure region is limited– Filament tripped off when P > 9.0 x 10-3Torr

• Customized RGA filament control schemes– P < 9.0 x 10-3Torr, filament is always on– P > 9.0 x 10-3Torr, filament on only for a short

time (10sec.) at end of wafer process, otherwise filament is off

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Real time control with integrated sensors like the RGA

Filament Status (On)

Chamber Pressure

AMU 28 (N2)

•Example of RGA control to sample at the end of a process run.

Process is complete. FDC sends the command to ignite the RGA filament.

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RGA contaminated bottle controlled test

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• A small Ar bottle that was purposely contaminated with 1600ppm of N2 was connected to a PVD chamber as a controlled test.

N2 Contamination

Rs

Sample

Time

Pre

ssur

e

* The Ar36 isotope was chosen for the graph instead of Ar40 because of the signal magnitude relative to the magnitude of N2.

Example 1: Real Time RGA Alarm

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•Ar should be present.•O2 and H2 are baseline signals.•N2 peak (pulse) detected.

Example 2: Chamber Lid Leak RGA Trace

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AMU28 (N2)- Red Chamber lid leak Blue Normal

Future Work

• Implementing RGA at house Ar gas supply– Detect problem at time close to t0– Minimize recovery

• Adding Real-time leak test recipes for maintenance and operators– Post chamber recovery– Weekly chamber integrity check

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Conclusion

• There is great value in integrating RGAs and other sensors into an in-house FDC system.– Sensor Control– Real time context with existing tool parameters– Real time detection

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Acknowledgement

• The authors want to express their appreciations for the valuable inputs on this project from Romek Bobkowski and Richard Groom, both of TriQuint Semiconductor Corporation on PVD processing and RGA operation respectively.

© 2013 TriQuint Semiconductor, Inc. 

© 2013 TriQuint Semiconductor, Inc.