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Q-pod

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Quartz Crystal Monitor
IPN 074-547-P1B

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Q-pod

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Quartz Crystal Monitor
IPN 074-547-P1B®

www.inficon.com©2012 INFICON

re achus@inficon.com

A

LTrademarks
The trademarks of the products mentioned in this manual are held by the companies that
produce them.
Q-pod™ is a trademark of INFICON GmbH.
Teflon® is a registered trademark of E. I. du Pont de Nemours and Company or its affiliates.
Windows®, is a registered trademark of Microsoft Corporation.
All other brand and product names are trademarks or registered trademarks of their respective companies.

Disclaimer
The information contained in this manual is believed to be accurate and reliable. However, INFICON assumes
no responsibility for its use and shall not be liable for any special, incidental, or consequential damages related
to the use of this product.
Due to our continuing program of product improvements, specifications are subject to change without notice.

Copyright©2012 All rights reserved.
Reproduction or adaptation of any part of this document without permission is unlawful.

DECLARATIONOFCONFORMITYThis is to certify that this equipment, designed and manufactured by:
INFICON Inc.
Two Technology Place
East Syracuse, NY 13057
USA
meets the essential safety requirements of the European Union and is placed on themarket accordingly. It has been constructed in accordance with good engineering
practice in safety matters in force in the Community and does not endanger the safetyof persons, domestic animals or property when properly installed and maintained andused in applications for which it was made.
Equipment Description:
Applicable Directives:

Q-Pod Quartz Monitor
2006/95/EC (LVD)
2004/108/EC (General EMC)
2002/95/EC (RoHS)

Applicable Standards:
Safety:EN 61010-1:2001

Emissions:

EN 61326-1:1997/A1: 1998/A2: 2001 (Radiated & Conducted Emissions)Class A: Emissions per Table 3(EMC – Measurement, Control & Laboratory Equipment)

Immunity:

EN 61326-1:1997/A1: 1998/A2: 2001 (General EMC)Class A: Immunity per Table A1(EMC – Measurement, Control & Laboratory Equipment)

RoHS:

Fully compliant

CE Implementation Date:
Authorized Representative:

April 2007 (Updated February 2011)
Steve Schill_________________________
Thin Film Business Line Manager
INFICON Inc.
ANY QUESTIONS RELATIVE TO THIS DECLARATION OR TO THE SAFETY OF INFICON'S PRODUCTS SHOULD BE
DIRECTED, IN WRITING, TO THE AUTHORIZED REPRESENTATIVE AT THE ABOVE ADDRESS.

Warranty
WARRANTY AND LIABILITY - LIMITATION: Seller warrants the products
manufactured by it, or by an affiliated company and sold by it, and described on
the reverse hereof, to be, for the period of warranty coverage specified below, freefrom defects of materials or workmanship under normal proper use and service.
The period of warranty coverage is specified for the respective products in therespective Seller instruction manuals for those products but shall not be less thantwo (2) years from the date of shipment thereof by Seller. Seller's liability under
this warranty is limited to such of the above products or parts thereof as are
returned, transportation prepaid, to Seller's plant, not later than thirty (30) days
after the expiration of the period of warranty coverage in respect thereof and arefound by Seller's examination to have failed to function properly because of
defective workmanship or materials and not because of improper installation or
misuse and is limited to, at Seller's election, either (a) repairing and returning the
product or part thereof, or (b) furnishing a replacement product or part thereof,transportation prepaid by Seller in either case. In the event Buyer discovers or
learns that a product does not conform to warranty, Buyer shall immediately notify
Seller in writing of such non-conformity, specifying in reasonable detail the natureof such non-conformity. If Seller is not provided with such written notification,
Seller shall not be liable for any further damages which could have been avoided if
Seller had been provided with immediate written notification.
THIS WARRANTY IS MADE AND ACCEPTED IN LIEU OF ALL OTHERWARRANTIES, EXPRESS OR IMPLIED, WHETHER OF MERCHANTABILITY OR
OF FITNESS FOR A PARTICULAR PURPOSE OR OTHERWISE, AS BUYER'S
EXCLUSIVE REMEDY FOR ANY DEFECTS IN THE PRODUCTS TO BE SOLDHEREUNDER. All other obligations and liabilities of Seller, whether in contract or
tort (including negligence) or otherwise, are expressly EXCLUDED. In no event
shall Seller be liable for any costs, expenses or damages, whether direct orindirect, special, incidental, consequential, or other, on any claim of any defective
product, in excess of the price paid by Buyer for the product plus returntransportation charges prepaid.
No warranty is made by Seller of any Seller product which has been installed,
used or operated contrary to Seller's written instruction manual or which has been
subjected to misuse, negligence or accident or has been repaired or altered byanyone other than Seller or which has been used in a manner or for a purpose forwhich the Seller product was not designed nor against any defects due to plans or
instructions supplied to Seller by or for Buyer.
This manual is intended for private use by INFICON® Inc. and its customers.
Contact INFICON before reproducing its contents.
NOTE: These instructions do not provide for every contingency that may arise inconnection with the installation, operation or maintenance of this equipment.
Should you require further assistance, please contact INFICON.

www. inficon.com

re achus@inficon.com

Q-pod Operating Manual

Table Of Contents
Trademarks
Disclaimer
Copyright
Chapter 1
Introduction
1.1
1.1.1
1.2
1.2.1
1.2.2
1.3
1.3.1
1.4
1.5
1.6
1.6.1
1.6.2

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Related Manuals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Instrument Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Definition of Notes, Cautions and Warnings. . . . . . . . . . . . . . . . . . . . . . . . . 1-2
General Cautions and Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
How to Contact INFICON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Returning Your Q-pod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Parts and Options Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Base Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Chapter 2

IPN 074-547-P1B

Quick Start
2.1
2.2
2.3
2.3.1
2.3.1.1

Install Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Connect the Q-pod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Using the Q-pod Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Main Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Reading Grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

2.3.1.2

Materials Grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

2.3.2
2.3.2.1

Setup Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
DataLog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

2.3.2.2

Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

2.3.2.3

Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

2.3.2.4

Q-pods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

2.3.3

Graph Display. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

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Q-pod Operating Manual

Chapter 3
Communications
3.1
3.2
3.3
3.3.1
3.3.2
3.3.3
3.4
3.5

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
ASCII Command Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
QPOD.DLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Registering QPOD.DLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Calculating Rate and Thickness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Sample Programs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Chapter 4
4.1
4.1.1
4.1.1.1

Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Status LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
LED illuminated steady. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.1.1.2

LED flashes slowly (about 2 Hz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.1.1.3

LED flashes rapidly (about 10 Hz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.1.2
4.1.3
4.1.4
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.3
4.3.1
4.3.1.1

Troubleshooting the Q-pod. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Troubleshooting Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Troubleshooting Computer Communications . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Replacing the Crystal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Front Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Cool Drawer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Bakeable Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
Sputtering Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
Crystal Snatcher. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
Crystal Sensor Emulator IPN 760-601-G2 . . . . . . . . . . . . . . . . . . . . . . . . . 4-15
Diagnostic Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Measurement System Diagnostic Procedure . . . . . . . . . . . . . . . . . . . . . . . 4-16

4.3.1.2

Feed-Through Or In-Vacuum Cable Diagnostic Procedure . . . . . . . . . . . . 4-17

4.3.1.3

Sensor Head Or Monitor Crystal Diagnostic Procedure. . . . . . . . . . . . . . . 4-18

4.3.1.4

System Diagnostics Pass But Crystal Fail Message Remains. . . . . . . . . . 4-19

4.3.2
4.3.2.1

Sensor Cover Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20
Compatible Sensor Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20

4.3.2.2

Incompatible Sensor Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20

4.3.3

Emulator Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-21

TOC - 2

IPN 074-547-P1B

Troubleshooting and MaintenanceQ-pod Operating Manual

Chapter 5
Calibration Procedures
5.1
5.2
5.3
5.4

Importance of Density, Tooling and Z-Ratio . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Determining Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Determining Tooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Laboratory Determination of Z-Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Chapter 6
Measurement and Theory
6.1
6.1.1
6.1.2
6.1.3
6.1.4

Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Monitor Crystals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Period Measurement Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4Z-match Technique. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Active Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

Appendix A
Material Table
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1

IPN 074-547-P1B

A.1

TOC - 3

Q-pod Operating Manual

IPN 074-547-P1B

This page is intentionally blank.

TOC - 4

Q-pod Operating Manual

Chapter 1
Introduction
1.1 Introduction
The INFICON Q-pod™ Transducer is a small, inexpensive and accurate way tomeasure thin film depositon rate and thickness. No external oscillator or powersource is required.
The included Q-pod software displays rate, thickness, frequency, crystal life and agraph of rate versus time, for up to 8 Q-pods simultaneously. Q-pod readings canbe logged to disk in spreadsheet friendly comma-delimited format.
There are also sample files included, written in Labview, Java and Visual Basic tohelp aid in the integration of the Q-pod into a system that is managed via software.
See section section 3.5, Sample Programs, on page 3-4 for more details.

IPN 074-547-P1B

Figure 1-1 Q-pod

When reading this Q-pod manual, please pay particular attention to the NOTES,CAUTIONS, and WARNINGS found throughout the text. The Notes, Cautions, andWarnings are defined in section 1.2.1 on page 1-2. Also, note the general warnings
in section 1.2.2, General Cautions and Warnings, on page 1-3.

1-1

Q-pod Operating Manual

1.1.1 Related Manuals
Sensors are covered in separate manuals. PDF files of these manuals arecontained in the 074-5000-G1 CD, part of the Ship Kit.
074-154 - Bakeable Sensor

074-156 - Front Load Sensor, Single/Dual074-157 - Sputtering Sensor

147-800 - Cool Drawer Sensor, Single/Dual

1.2 Instrument Safety
1.2.1 Definition of Notes, Cautions and Warnings
When using this manual, please pay attention to the NOTES, CAUTIONS andWARNINGS found throughout. For the purposes of this manual they are defined asfollows:
NOTE: Pertinent information that is useful in achieving maximum instrument
efficiency when followed.

CAUTION
Failure to heed these messages could result in damage
to the instrument.

Failure to heed these messages could result in personal
injury.

WARNING - Risk Of Electric Shock
Dangerous voltages are present which could result inpersonal injury.

1-2

IPN 074-547-P1B

WARNINGQ-pod Operating Manual

1.2.2 General Cautions and Warnings
CAUTION
Do not open the instrument case! There are nouser-serviceable components within the instrument
case.
Refer all maintenance to technically qualified personnel.

WARNING
Failure to operate the Q-pod in the manner intended by
INFICON can circumvent the safety protection provided
by the instrument and may result in personal injury.

CAUTION

IPN 074-547-P1B

Q-pod may not be suitable for use with RF sputteringsystems or other electrically noisy environments.

1-3

Q-pod Operating Manual

1.3 How to Contact INFICONWorldwide customer support information is available under Support at
www.inficon.com where you can contact:
A Technical Support Engineer with questions regarding applications for andprogramming the Q-pod.



A Service Engineer with questions regarding troubleshooting, diagnosing or
repairing a defective Q-pod.

Sales and Customer Service, to find the INFICON Sales office nearest to you.



Repair Service, to find the INFICON Service Center nearest to you.

If you are experiencing a problem with your Q-pod, please have the following
information readily available:


The serial number and firmware version for your Q-pod.

A description of your problem.

An explanation of any corrective action that you may have already attempted.

The exact wording of any error messages that you may have received.

1.3.1 Returning Your Q-pod
Do not return any component of your Q-pod to INFICON without first speaking witha Customer Support Representative. You must obtain a Return Material
Authorization (RMA) number from the Customer Support Representative.
If you deliver a package to INFICON without an RMA number, your package will beheld and you will be contacted. This will result in delays in servicing your Q-pod.

Frequency Range. . . . . . . . . . . . . . . 1 to 6 MHz
Frequency Resolution . . . . . . . . . . . 0.05 Hz at 6 MHz @ 2 measurements per
second)Frequency Accuracy . . . . . . . . . . . . 0.002%
Frequency Stability . . . . . . . . . . . . . . ±2 ppm total, over 0º to 50ºC
Thickness & Rate Resolution . . . . . . 0.0613 Å (new crystal); 0.1091 Å (crystal @4.5 MHz); over 500 ms sample for material
density = 1.0, Z-ratio = 1.0
Input . . . . . . . . . . . . . . . . . . . . . . . . . BNC
Interface & Power. . . . . . . . . . . . . . . USB, v2.0 or later, 15 ft. (457 cm) maximum
allowable length
Size . . . . . . . . . . . . . . . . . . . . . . . . . 1 in. x 2 in. x 2.5 in. (25 mmx 50 mm x 64 mm)

1-4

IPN 074-547-P1B

1.4 Specifications

Q-pod Operating Manual

Weight . . . . . . . . . . . . . . . . . . . . . . . 2 oz. (32 gm)
Computer Requirements . . . . . . . . . Any PC running Windows® XP / 2000 /Windows 7 32-bit with one available USB
port for each Q-pod

1.5 Unpacking and Inspection
1 If the Q-pod has not been removed from its packaging, do so now.
2 Carefully examine the card for damage that may have occurred during
shipping. This is especially important if you notice obvious rough handling on
the outside of the container. Immediately report any damage to the carrier and
to INFICON.

3 Do not discard the packing materials until you have taken inventory and haveat least performed successful installation.

4 Take an inventory of your order by referring to your order invoice and theinformation contained in section 1.6.1.

5 To install the Q-pod, see Chapter 2, Quick Start.
6 For additional information or technical assistance, contact INFICON, refer tosection 1.3 on page 1-4.

1.6 Parts and Options Overview
1.6.1 Base Configuration
Q-pod Transducer w/Software . . . . . . . . .Q-POD
10 ft. USB Cable. . . . . . . . . . . . . . . . . . . .068-0472
IPN 074-547-P1B

6 in. BNC Cable . . . . . . . . . . . . . . . . . . . .755-257-G6
Technical Manual . . . . . . . . . . . . . . . . . . .074-547 on 074-5000-G1 CD
5.5 MHz Test Crystal . . . . . . . . . . . . . . . .782-902-023

1.6.2 Sensors
Front Load Single Sensor. . . . . . . . . . . . . . . . . . . . . SL-XXXXX
Cool Drawer Single Sensor . . . . . . . . . . . . . . . . . . . CDS-XXFXX
Sputtering Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . 750-618-G1
Front Load UHV Bakeable Sensor . . . . . . . . . . . . . . BK-AXF
NOTE: Multi-crystal (rotary) sensors & dual sensors should not be used with the
Q-pod.

1-5

Q-pod Operating Manual

IPN 074-547-P1B

This page is intentionally blank.

1-6Q-pod Operating Manual

Chapter 2
Quick Start
2.1 Install Software
NOTE: If this is the initial Q-pod installation on this computer, you should install the
Q-pod Software before connecting a Q-pod to the USB port.

1 Place the INFICON Program Disk in the computer’s CD-ROM.
2 Ignore the prompt and double-click the My Computer icon.
3 Right-click the CD-ROM icon, then click Open.
4 Double-click the Q-pod Transducer file.
5 Double click QPOD_V#_SETUP.EXE.
6 Follow the on screen directions and select the default installation options.
7 When software installation is complete, exit the installation program.

2.2 Connect the Q-pod
1 Connect the USB cable to a computer USB port, then to the Q-pod. See Figure
2-1.

1a If you are prompted to install the Q-pod drivers, select Install the Software
Automatically.

1b If you are prompted concerning Windows Logo Testing, select Continue
Anyway.

IPN 074-547-P1B

Figure 2-1 Q-pod Connections

2-1

Q-pod Operating Manual

2 Use the 6 in. BNC cable provided to connect the Q-pod to the QCM sensor
feedthrough.

3 The status light on the Q-pod illuminates when a quartz crystal is detected.

2.3 Using the Q-pod Software
Click the Q-pod desktop icon, or click Start >> Programs >> Sigma Instruments>> Q-pod. If you are prompted to assign Q-pod(s) to a channel, click Yes. Click
Help to get more detailed information on materials and operation. Select Setup orGraph on the Main Screen menu to change the main screen display mode. See
Figure 2-2.

2.3.1 Main Display
The top of the main screen is the main display. Here the Start button is used to startand record a run. Run time and run number are shown, along with the current timeand date. The option to datalog during any given run is also given.
2.3.1.1 Reading Grid
The left grid displays the measured values of each connected Q-pod. Click Start todisplay Rate and Thickness readings. Frequency and Life readings are always
displayed. Click a channel’s Zero button to zero the channel thickness reading.
Shift-Click any channel Zero button to zero all thicknesses.

2-2

IPN 074-547-P1B

Figure 2-2 Main Screen

Q-pod Operating Manual

2.3.1.2 Materials Grid
In the right grid, edit the Density, Z-Factor and Tooling values for the materials
being deposited. Move your mouse over each setting to see a brief description.

2.3.2 Setup Display
The lower section of the main screen is where run parameters can be changed and
Q-pod communication information is presented.
2.3.2.1 DataLog
Sets the file name, location and operation of disk data logging. Data log files canbe set to overwrite the file name each time it is saved. It can append the data, byadding the newly recorded data to the end of the same file. It can also save eachrun in a new file designated by run number. Data is saved in comma delimited
format for easy import into a spreadsheet.
2.3.2.2 Measurement
Sets the basic measurement parameters for all Q-pods. The values shown above
are correct for most applications.
2.3.2.3 Display

IPN 074-547-P1B

Sets the display parameters.Thickness can be displayed in kÅ or Å. Mass can bedisplayed in ug/cm2. Rate will be changed to ng/cm2/sec if mass is the chosen
option. Resolution of displayed readings may also be changed here (0.0 or 0.00).
The rate reading filter can be set in this section. The Filter number represents how
many measurements are averaged together to produce the displayed rate. The
number of Q-pods being used is defined in this section as well.
2.3.2.4 Q-pods
Sets the name and displays the serial number of the Q-pod assigned to eachmeasurement channel. A strike-through serial number indicates the Q-pod is notconnected. The software can monitor a maximum of 8 Q-pods simultaneously.

2-3

Q-pod Operating Manual

2.3.3 Graph Display
Figure 2-3 Graph Display

IPN 074-547-P1B

Graphs the deposition rate, thickness, or frequency of active measurement
channels when Start is clicked. The graph viewed can be changed from the view
option on the toolbar on the main screen. Settings to the right of the graph control
basic graph functions. See the Help menu for advanced graph setup.

2-4Q-pod Operating Manual

Chapter 3
Communications
3.1 Introduction
The Q-pod communicates via a USB (or USB2) port and a simple ASCII commandset. An ActiveX DLL (Qpod.DLL) provides functions to set parameters, takereadings, and handle USB communications.

3.2 ASCII Command Set
The commands below assume you can open the proper USB port forcommunications. The section on Qpod.DLL provides the tools needed tocommunicate with the Q-pod without knowledge of USB functions.
A Q-pod command consists of an exclamation character (&H21), then thecommand as detailed below, and terminated with a Carriage Return (&H13) andLine Feed (&H10). The response has the same format, that is !<response>CrLf.
@ Get version
Returns: Qpod VX.XX
A# Get Frequency and Set Status LED
Returns frequency counts. The B & C commands (see below) must be used to
set the measurement period before using this command. The response is gate
counts, which are converted crystal frequency using:
Freq = 200 MHz * GatePeriod / Response
IPN 074-547-P1B

A response of –1 indicates that a new reading is not available.
The value sent with this command activates the Status LED. Send A1 to turnon the LED (crystal good), or A0 to cause the LED to flash at the measurement
rate (crystal fail).
B# Set Gate Period
Sets the longest measurement period, determined by the lowest valid crystal
frequency. If the desired measurement period is 0.25 seconds, and theminimum crystal frequency is 5.0MHz, then the command is: B1250000 (0.25
x 5MHz).
C# Set Measurement Period
The value sent is the period in seconds times the reference oscillator frequency,
50MHz. If the desired measurement period is 0.25 seconds, then the command
is: C12500000 (0.25 x 50MHz)

3-1

Q-pod Operating Manual

3.3 QPOD.DLL
QPOD.DLL is an Active-X DLL that provides the functions necessary to get rate
and thickness readings from up to 32 Q-pods.
In the function listings that follow, parameter and return value types are indicatedby the first letter of the variable name:i: Integer (16 bits)

f: Float (single)

c: Char (8 bits)

l: Long (32 bits)

d: Double

b: Byte (8 bits)

s: String

Functions parameters are passed By Value unless specifically designated as
ByReference (pointer).
Unless noted otherwise, the return values of functions are:
QPOD_SUCCESS = &H0 . . . . . . . . . Command successful
QPOD_BUSY = &H1. . . . . . . . . . . . . Communications already in progress
QPOD_TIMEOUT = &H2 . . . . . . . . . Did not respond
QPOD_NOREADING = &H3 . . . . . . No new reading ready
QPOD_OVERFLOW = &H4 . . . . . . Internal overflow error
QPOD_BADPARAM = &H5. . . . . . . Bad parameter value
QPOD_BADCMD = &H6 . . . . . . . . . Bad command
QPOD_BADSERNUM = &H7 . . . . . Serial number not connected
QPOD_XTALFAIL = &H8 . . . . . . . . . Crystal fail
QPOD_COMMERR = &H9 . . . . . . . . Unknown communications error

3.3.1 Registering QPOD.DLL
QPOD.DLL and ccrpTmr.DLL (used for timing functions) must be registered byWindows. The QpodDLL setup program installs and registers both files. To installand register them manually, copy both files to the Windows\System32 folder.
Click Start, Run, and typeregsvr32\windows\system32\qpod.dll
click OK, then typeregsvr32\windows\system32\ccrpTmr.dll
and click OK.

3-2

IPN 074-547-P1B

QPOD_UNKERR = &H99 . . . . . . . . . Unknown program error

Q-pod Operating Manual

3.3.2 Functions
FindQpods (By Ref sSNArray(0 to 32)) [=lRtnVal]
Searches for Q-pods connected to the computer. Populates sSNArray() withthe serial numbers of up to 32 Q-pods. Return value is total number of Q-pods
found.
Most QPOD.DLL functions require the serial number of a Q-pod as their firstparameter. FindQpods should the first function called. Additional calls to
FindQpods can be made, but be sure to resend the parameters (period,
density, etc.) for each Q-pod serial number you will use.
InitFreq (dFmax, dFmin, dFinit) [=lRtnVal]
Initializes the maximum, minimum, and initial crystal frequency values for all
attached Q-pods. The default values are Fmax=6.1 MHz, Fmin=5.0 MHz,
Finit=6.0 MHz,. Crystal readings >Fmax or <Fmin will generate a crystal failresponse to the GetReadings call. Call InitFreq immediately after FindQpods.
GetReading (sSerNum, By Ref dRdgArray(0 to 3)) [=lRtnVal]
Populates dRdgArray with the Rate, Thickness, Frequency, and %Life for the
Q- pod serial number. Thickness is returned in kA.
You can call get readings and test the return value to see if a new readings was
ready (&H0) or not (&H3). Alternatively, you can set the Reading Timer and
QPOD.DLL will raise a QpodReading event when a reading is ready. See
SetReading Timer() and QpodReading() below.
Material (sSerNum, dDensity, dZFactor, dTooling) [=lRtnVal]

IPN 074-547-P1B

Sets the Density, Z Factor, and Tooling used to convert frequency change into
rate and thickness.
Period (sSerNum, dPeriod) [=lRtnVal]
Sets the measurement period in seconds. Valid values are 0.1 to 2.
SetReadingsTimer (dInterval) [=lRtnVal]
Sets the interval for polling Qpods for readings in milliseconds. A value of zerodisables the QpodReadings event (see below).
Zero (sSerNum) [=lRtnVal]
Sets the Q-pod thickness reading to zero.
ZeroAll () [=lRtnVal]
Sets all attached Q-pod thickness readings to zero.
Revision (sSerNum, ByRef sRev) [=lRtnVal]
Returns the firmware revision in sRev. A sRev value is: Qpod V1.00.

3-3

Q-pod Operating Manual

3.3.3 Events
QpodReading (sSerNum, ByRef dRdgArray(0 to 3), Time)
If SetReadingsTimer (see above) is passed a non-zero interval, the QPOD.DLL
will poll every attached Q-pod for readings at the set interval.
For each Q-pod that has a new reading, a QpodReading event is raised. The
sSerNum parameter is the serial number of the Q-pod with a new reading. The
array dRdgArray holds Rate, Thickness, Frequency, and %Life for that Q-pod
serial number. Thickness is returned in kA.

3.4 Calculating Rate and Thickness
In the Q-pod software, thickness and rate are calculated using the Z-match
equation. The calculation can be divided into four parts:

1 Calculate Thickness:
Thickness = (AT_CONST * DENS_QUARTZ) / (PI * Density * Freq * ZRatio)
where AT_CONST = 16.68 x 1012, DENS_QUARTZ= 2.648, PI=3.1416,
Freq is the frequency calculated from the A command.

2 Correct for Z-Ratio:
Thicknessz = Thickness * ArcTan(ZRatio * Tan(PI * (FreqInit - Freq) / FreqInit))
where Thickness was calculated in step 1 and FreqInit is the initial (new)crystal frequency – typically 6MHz.

3 Correct for Tooling:
ThicknessT = Thicknessz * Tooling * 0.01

Rate = (ThicknessT – ThicknessT-1) / Period
where ThicknessT was calculated in step 3, ThicknessT-1 was from the lastmeasurement, and Period is the elapsed time between measurements.

3.5 Sample Programs
On the INFICON CDROM in D:\Qpod Transducer_V100_SAMPLES.exe, run thisexecutable to set up the sample files for the Q-pod. When complete, they will belocated here: C:\Program Files\Sigma Instruments\Q-pod\Sample Programs.
These are sample interface files for use in Visual Basic and LabVIEW. These files
are meant to act as means to aid the user in creating their own software and toallow the user to interface to the Q-pod with other devices in your operation.
NOTE: For the sample programs to work correctly, you should also install Sigma's
Q-pod application.

3-4

IPN 074-547-P1B

4 Calculate Rate:Q-pod Operating Manual

Before using the LabVIEW demo, it may be best to familiarize oneself with
operation of the Q-pod software. To run the LabVIEW demo(qpod.vi), click "LoadDLL", "Use Card" and then set the Sensor parameters as desired. Click "Start" todisplay readings. Be sure to click "Unload DLL" before stopping the LabVIEW
program. Otherwise, a Windows error may occur, and LabVIEW may shut down.
LabVIEW 6 or higher is required.
NOTE: The sample LabView VI may require that you select the proper DLL for thetwo Automation RefNum controls. Right click each control, then click
Select ActiveX Class. Check Show Creatable Objects Only, then selectSigma Instruments Qpod ActiveX DLL.

IPN 074-547-P1B

Figure 3-1 Labview Sample Program

3-5

Q-pod Operating Manual

IPN 074-547-P1B

This page is intentionally blank.

3-6Q-pod Operating Manual

Chapter 4
Troubleshooting and Maintenance
4.1 Troubleshooting Guide
If the Q-pod fails to function, or appears to have diminished performance, thefollowing Symptom/Cause/Remedy charts may be helpful.

CAUTION
There are no user serviceable components within the
Q-pod case.
Refer all maintenance to qualified personnel.

4.1.1 Status LED
If there is a problem with the Q-pod, the status LED will indicate as to the likely
cause.
4.1.1.1 LED illuminated steadyGood crystal detected

IPN 074-547-P1B

4.1.1.2 LED flashes slowly (about 2 Hz)No crystal connected

Crystal frequency range not set correctly in software

Crystal failure

4.1.1.3 LED flashes rapidly (about 10 Hz)
Software not installedDriver not installed

Q-pod not detected by softwareQ-pod not assigned to a sensor channel (click Find to locate Q-Pod and thenfollow instructions to assign Q-Pod to a sensor channel)

Q-pod hardware failure

4-1

Q-pod Operating Manual

4.1.2 Troubleshooting the Q-pod
Table 4-1 General Troubleshooting

SYMPTOM
1. Crystal fail message isalways on.

CAUSE

REMEDYa. Q-pod and/or sensor notconnected.

a. Verify proper
Q-pod/sensor connections.

b. Q-pod malfunctioning.

b. If available, insert a known
working Q-pod, or othermonitor, in place of suspect
one; if Q-Pod is confirmed
bad, contact INFICON
service department.

c. Defective cable fromfeedthrough to Q-pod.

c. Use an Ohm meter or
DMM to check electricalcontinuity or isolation as
appropriate.

d. Poor electrical contact in d. Use an Ohm meter orthe sensor, feedthroughs, or DMM to check electricalcontinuity or isolation as
in-vacuum cable.
appropriate.
e. Failed crystal/no crystal.

e. Replace crystal with new
INFICON crystal.

g. Frequency of crystal out of g. Verify that the crystal
range,
frequency is within therequired range, use
INFICON crystals. Set thedesired range on the main
screen on the software.

4-2

IPN 074-547-P1B

f. Two crystals placed into the f. Remove one of thecrystal holder.
crystals.

Q-pod Operating Manual
Table 4-1 General Troubleshooting

SYMPTOM
2. Noisy signal

CAUSE
a. Distance from sensor to
Q-pod is longer than 40 in.
(101.6 cm).

REMEDYa. Replace cables topreserve the maximum
allowable length.

b. Mechanical/electric noise b. Look for potential noise
sources located near thesources. Reposition the
Q-pod/cable .
Q-pod/cables accordingly.
3. Frequency reading isunstable or driftinga. Control the temperature ofa. Temperature (of thethe chamber. Check watering
crystal) is changing. An
AT-cut crystal frequency may cooling for flow andtemperature. Check source
drift as much as 10 Hz/°C.
to crystal distance (12 in. isideal).
b. Control the humidity of theb. Humidity (level on the
crystal) is changing. Moisture chamber.
being absorbed or exuded
from the crystal surface,

IPN 074-547-P1B

4.1.3 Troubleshooting Sensors
NOTE: Many sensor head problems may be diagnosed with a DMM (Digital
Multi-Meter). Disconnect the short oscillator cable from the feedthroughand measure the resistance from the center pin to ground. If the reading isless than 10 megohms, the source of the leakage should be found andcorrected. Likewise, with the vacuum system open check for center
conductor continuity, a reading of more than 1 ohm from the feedthroughto the Q-pod indicates a problem. Cleaning contacts or replacing thein-vacuum cable may be required.
A somewhat more thorough diagnosis may be performed with the optional
Crystal Sensor Emulator, 760-601-G1. See section 4.3 on page 4-15 for a
discussion of its use and diagnostic capabilities.A more detailed
troubleshooting guide is shipped with the sensor. Refer to that manual for
more detailed information in some cases.

4-3Q-pod Operating Manual

Table 4-2 Troubleshooting Sensors

SYMPTOM
1. Large jumps of thickness
reading during deposition.

CAUSE
a. Mode hopping.

REMEDYa. Mode hopping is a
byproduct of active
oscillation with a heavily
damped crystal. Temperaturestabilization is key indiminishing this. Replace thecrystal.

b. Stress causes film to peel b. Replace crystal or use
from crystal surface.
high performance
RunSaver™ crystal; consult
factory.
c. Particulate or "spatter"from molten source striking
crystal.

c. Thermally condition thesource thoroughly before
deposition, use a shutter toprotect the crystal during
source conditioning.

4-4

e. Small pieces of material
fell on crystal (for crystal
facing up sputteringsituation.)e. Check the crystal surface
and blow it off with clean air.

f. Small pieces of magnetic
material being attracted by
the sensor magnet andcontacting the crystal(sputtering sensor head.)f. Check the sensor cover's
aperture and remove any
foreign material that may be
restricting full crystal
coverage.

IPN 074-547-P1B

d. Clean and polish thed. Material build up,
scratches or foreign particles crystal seating surface on theon the crystal holder seating crystal holder.
surface (improper crystal
seating.)Q-pod Operating Manual
Table 4-2 Troubleshooting Sensors

SYMPTOM

CAUSE

2. Crystal ceases to oscillate a. Crystal struck byparticulate or spatter fromduring deposition before it
reaches the end of its normal molten source.
life.

REMEDYa. Thermally condition thesource thoroughly before
deposition, use a shutter toprotect the crystal during
source conditioning.

b. Material on crystal holder b. Clean crystal holder.
partially masking crystal
cover aperture.
c. Existence of electricalshort or open condition.

c.Using an ohm meter orDMM, check for electricalcontinuity in the sensor
cable, connector, contact
springs, connecting wire
inside sensor, andfeedthroughs.

d. Thermally induced
electrical short or open
condition.

d. See 2c above.

NOTE: Crystal life is highly dependent on process conditions of rate, power radiated fromsource, location, material, and residual gas composition.

IPN 074-547-P1B

3. Crystal does not oscillate a. Intermittent or pooror oscillates intermittently
electrical contact (contacts(both in vacuum and in air.) oxidized.)a. Use an Ohm meter or
DMM to check electricalcontinuity, clean contacts.

b. Leaf springs have lostb. Carefully bend leaves toretentivity (ceramic retainer, approx. 45° on ceramic
center insulator.)retainer and 60° inside thesensor head.
c. RF interference fromsputtering power supply.

c. Verify earth ground, useground strap adequate for
RF ground, change locationof Q-pod and cabling awayfrom RF power lines.

d. Cables not connected, or d. Verify proper connections,connected to wrong sensor and inputs relative toprogrammed sensor
input.
parameter.

4-5Q-pod Operating Manual
Table 4-2 Troubleshooting Sensors

SYMPTOM

CAUSE

a. Crystal was near the end
4. Crystal oscillates invacuum but stops oscillation of its life; opening to air
causes film oxidation which
after open to air.
increases film stress.
b. Excessive moistureaccumulates on the crystal.

REMEDYa. Replace crystal.

b. Turn off cooling water tosensor prior to venting, flow
warm water through sensor
while chamber is open.

a. Check cooling water flow
5. Thermal instability: large a. Inadequate coolingrate, be certain that coolingchanges in thickness reading water/cooling watertemperature too high.
water temperature is lessduring source warm-up
than 30°C; refer to(usually causes thickness
appropriate sensor manual.
reading to decrease) andafter the termination of
b. Excessive heat input to the b. If heat is due to radiation
deposition (usually causes
crystal.
from the evaporation source,
thickness reading tomove sensor further away
increase.)from source and use silver
crystals for better thermal
stability; install radiation
shield.

d. Crystal heating caused by d. Use a sputtering sensor
head.
high energy electron flux
(often found in RF
sputtering.)
e. Poor thermal transfer(Bakeable.)

4-6

f. Use Al or Au foil washer
between crystal holder andsensor body.

IPN 074-547-P1B

c. Crystal not seated properly c. Clean or polish the crystal
in holder.
seating surface on the crystal
holder.

Q-pod Operating Manual
Table 4-2 Troubleshooting Sensors

SYMPTOM
6. Poor thickness
reproducibility.

IPN 074-547-P1B

7. Large drift in thickness(greater than 200 Å for adensity of 5.00 g/cc) aftertermination of sputtering.

CAUSE

REMEDYa. Variable source flux
distribution.

a. Move sensor to a more
central location to reliably
sample evaporant, ensure
constant relative pool heightof melt, avoid tunneling into
the melt.

b. Sweep, dither, or position
where the electron beam
strikes the melt has beenchanged since the lastdeposition.

b. Maintain consistent source
distribution by maintaining
consistent sweep
frequencies, sweep
amplitude and electron beam
position settings.

c. Material does not adhere
to the crystal.

c. Make certain the crystal
surface is clean; avoid
touching crystal with fingers,
make use of an intermediate
adhesion layer.

d. Cyclic change in rate.

d. Make certain source's
sweep frequency is not"beating" with the Q-pod’smeasurement frequency.

a. Crystal heating due to poor a. Clean or polish the crystal
thermal contact.
seating surface on the crystal
holder.
b. External magnetic fieldinterfering with the sensor's
magnetic field (sputtering
sensor.)b. Rotate sensor magnet toproper orientation withexternal magnetic field, referto the sputtering sensor
manual IPN 074-157.

c. Sensor magnet cracked or c. Check sensor magnetic
demagnetized (sputtering
field strength, the maximum
sensor.)field at the center of theaperture should be 700
gauss or greater.

4-7

Q-pod Operating Manual

4.1.4 Troubleshooting Computer Communications
Table 4-3 Troubleshooting Computer Communications

SYMPTOM

CAUSE

1. Communications cannot a. Improper cablebe established between the connection.
host computer and the
Q-pod.
b. Driver not installed
properly.

REMEDYa. Verify for cableconnections are seatedproperly.
b. Reinstall drivers. Confirm
the operating sytem is anaccepted OS. If autorun
driver install feature does
not work, the driver can beinstalled from the device
manager manually.

4.2 Replacing the Crystal
CAUTION
Always use clean nylon lab gloves and plastic tweezers
for handling the crystal (to avoid contamination which
may lead to poor adhesion of the film to the electrode).

Do not use excessive force when handling the ceramic
retainer assembly since breakage may occur.
NOTE: Certain materials, especially dielectrics, may not adhere strongly to the
crystal surface and may cause erratic readings.
NOTE: Thick deposits of some materials, such as SiO, Si, and Ni will normally peel
off the crystal when it is exposed to air, as a result of changes in film stresscaused by gas absorption. When you observe peeling, replace thecrystals.

4-8

IPN 074-547-P1B

Do not rotate the ceramic retainer assembly after it isseated (as this will scratch the crystal electrode andcause poor contact).

Q-pod Operating Manual

4.2.1 Front Load
Follow the procedure below to replace the crystal in the Front Load sensor: (seeFigure 4-1)

1 Gripping the crystal holder with your fingers, pull it straight out of the sensor
body.

2 Gently pry the crystal retainer from the holder (or use the Crystal Snatcher; see
Figure 4-6 on page 4-14).

3 Turn the retainer over and the crystal will drop out.
4 Install a new crystal, with the patterned electrode face up.
5 Push the retainer back into the holder and replace the holder in the sensor
body.
Figure 4-1 Front Load Crystal Sensor (Exploded)

Front Load Crystal Holder(IPN 750-172-G1)

IPN 074-547-P1B

Crystal (IPN 008-010-G10)
Fully Coated Face (Gold)

Crystal Retainer(IPN 007-023)

Finger Spring Contact(IPN 750-171-P1)

Front Load Standard
Crystal Sensor Body
(IPN 750-207-G1)

In-Vacuum Cable
To XIU

Water Tubes

4-9

Q-pod Operating Manual

4.2.2 Cool Drawer
Follow the procedure below to replace the crystal in a Next Generation Cool
Drawer™ sensor:

1 Using your thumb and index fingers, gently squeeze the sides of the retainer at
the mid section then lift it up, away from the drawer, as shown in Figure 4-2.

2 Hold the drawer by the handle and turn it upside down to remove the spent
crystal.

3 Install a new crystal in the drawer. Observe its orientation. The patternelectrode should face upward as shown in Figure 4-3.

4 Hold the retainer by its sides. Align its orientation notch with the drawer thengently and evenly push the retainer down until it snaps firmly into the drawer.
see Figure 4-3. Never push down (or pull up) on the contact spring, doing so
may permanently damage it.

5 Inspect the whole assembly. The retainer should be even and engage thedrawer at all four corners.
Figure 4-2 Cool Drawer - Removing The Crystal

IPN 074-547-P1B

Contact Spring

4 - 10Q-pod Operating Manual
Figure 4-3 Cool Drawer - Replacing The Crystal

Retainer

CrystalOrientation
Notch

Handle

IPN 074-547-P1B

Drawer

4 - 11

Q-pod Operating Manual

4.2.3 Bakeable Sensor
For the Bakeable sensor, the procedure is the same as the Front Load sensor
except that you must first unlock the cam assembly by flipping it up. Once thecrystal has been replaced, place a flat edge of the holder flush with the cammechanism and lock it in place with the cam. See Figure 4-4.
Figure 4-4 Bakeable Crystal Sensor

Crystal Holder andRetainer Spring
IPN 750-218-G1

Crystal IPN 008-010-G10
Fully Coated Face (Gold)
Crystal Retainer IPN 007-064
Clamping Spring IPN 007-094

Contact IPN 007-099
Spreader Bar
IPN 007-267-P2

Insulator IPN 007-103

Shoulder Washer
IPN 007-269-P1
Cam Mechanism
IPN 007-095
Cover IPN 007-101

4 - 12

IPN 074-547-P1B

Shoulder Washer
IPN 007-268-P1
Two RequiredQ-pod Operating Manual

4.2.4 Sputtering Sensor
Observe the general precautions for replacing crystals and follow the instructions
below to replace the crystal in a sputtering sensor.

1 Grip the body assembly with your fingers and pull it straight out to separate itfrom the water-cooled front cover. (You may have to disconnect the sensor
cable in order to separate the parts.) See Figure 4-5.

2 Pull the crystal holder straight out from the front of the body assembly.
3 Remove the ceramic retainer from the crystal holder by pulling it straight out
with the crystal snatcher (see section 4.2.5 on page 4-14).

4 Turn the crystal holder over so that the crystal drops out.
5 Install a new crystal into the crystal holder with the patterned electrode facing
the back and contacting the leaf springs on the ceramic retainer.

6 Put the ceramic retainer back into the crystal holder and put the holder into thebody assembly of the sensor.

7 Align the position of the body assembly so that the connector matches with thenotch on the front cover of the sensor. Snap the two parts together. Reconnect
the sensor cable if it has been disconnected.
Figure 4-5 Sputtering Crystal Sensor
Body Assembly
IPN 750-619-G1
In-Vacuum Cable Assembly(29 in.) IPN 007-044

IPN 074-547-P1B

Ceramic Retainer
IPN 007-023
Crystal
IPN 008-009-G10(Silver)
Crystal Holder
IPN 007-049

Sensor
Front Cover
IPN 007-047

4 - 13

Q-pod Operating Manual

4.2.5 Crystal Snatcher
Use the crystal snatcher, supplied with the sensor, as follows:

1 Insert crystal snatcher into ceramic retainer (1) and apply a small amount ofpressure. This locks the retainer to the snatcher and allows the retainer to bepulled straight out (2). See Figure 4-6.

2 Reinsert the retainer into the holder after the crystal has been replaced.
3 Release the crystal snatcher with a slight side-to-side motion.

IPN 074-547-P1B

Figure 4-6 Use of the Crystal Snatcher

4 - 14

Q-pod Operating Manual

4.3 Crystal Sensor Emulator
IPN 760-601-G2
NOTE: 760-601-G2 is fully compatible with all Thin Film Deposition Controllers.
The Crystal Sensor Emulator option is used in conjunction with the Thin Film
Deposition Controller to rapidly diagnose problems with the Deposition Controller's
measurement system. See Figure 4-7.
Figure 4-7 Crystal Sensor Emulator

Female
BNC
Connector

SensorCoverConnector

FemaleMicrodot
Connector

The Crystal Sensor Emulator may be attached at various points in themeasurement system, from the oscillator to the sensor head. It provides a known
good monitor crystal with known good electrical connections. Using the emulator
and the controller in a systematic manner provides a fast means of isolating
measurement system, cable, or sensor problems. See Figure 4-8.
Figure 4-8 Crystal Sensor Emulator Attachment Points

Sensor Head

IPN 074-547-P1B

B

Thin Film
Controller

A

C

Crystal Interface
Unit (Oscillator)

CAUTION
This product is designed as a diagnostic tool, and is notintended for use in vacuum. Do not leave the Crystal
Sensor Emulator installed in the vacuum system during
processing.

4 - 15

Q-pod Operating Manual

4.3.1 Diagnostic Procedures
The following diagnostic procedures employ the Crystal Sensor Emulator to
analyze a constant Crystal Fail message. The symptom is a Crystal Fail message
that is displayed by the Q-pod software even after the monitor crystal has been
replaced with a new good monitor crystal.
4.3.1.1 Measurement System Diagnostic Procedure

1 Refer to Figure 4-8 on page 4-15. Remove the six-inch BNC cable from theFeed-Through at point A.

2 Connect the Crystal Sensor Emulator to the 6 inch BNC cable at Point A.


If the Crystal Fail message disappears after approximately five seconds,
the measurement system is working properly. Re-install the six-inch BNC
cable to the Feed-Through. Go to section 4.3.1.2.



If the Crystal Fail message remains, continue at step 3.

3 Disconnect the six-inch BNC cable from the Oscillator and from the Emulator.
4 Visually inspect the six-inch BNC cable to verify that the center pins are seatedproperly.

5 Use an Ohm meter to verify the electrical connections on the six-inch BNC
There must be continuity (<0.2 ohms, after accounting for resistance ofohmeter leads) between the center pins.



There must be isolation (>10 megohms) between the center pins and theconnector shield.

There must be continuity between the connector shields.

Replace the six-inch BNC cable if it is found to be defective and repeat Step 2of this procedure.

6 If the six-inch BNC cable is not defective, re-connect the six-inch cable to theoscillator and to the Crystal Sensor Emulator. If the Crystal Fail message
remains, contact INFICON.

4 - 16

IPN 074-547-P1B

cable.

Q-pod Operating Manual

4.3.1.2 Feed-Through Or In-Vacuum Cable
Diagnostic Procedure

1 Refer to Figure 4-8 on page 4-15. Remove the In-Vacuum cable from theSensor Head at point B.

2 Connect the Crystal Sensor Emulator to the In-Vacuum cable.


If the Crystal Fail message disappears after approximately five seconds,
the Feed-Through and In-Vacuum Cable are working properly. Re-install
the In-Vacuum cable to the Sensor Head. Go to section section 4.3.1.3 on
page 4-18.



If the Crystal Fail message remains, continue at step 3.

3 Disconnect the In-Vacuum cable from the Feed-Through and the Emulator.
Disconnect the six-inch BNC cable from the Feed-Through.

4 Using an Ohm Meter, verify electrical continuity from the BNC center pin on the
Feed-Through to the Microdot center pin on the Feed-Through. A typical value
would be less than 0.2 ohms.

5 Verify electrical isolation of the center pin on the Feed-Through from theelectrical ground (Feed-Through body). A typical value would be in excess of
10 megohms.
If the Feed-Through is found to be defective, replace the Feed-Through, re-attach
the BNC and In-Vacuum cables, and repeat this procedure starting at Step 2,otherwise continue at step 6.

6 Verify electrical continuity from center pin to center pin on the In-Vacuum cable.
7 Verify that the center pin of the In-Vacuum cable is electrically isolated from the

IPN 074-547-P1B

In-Vacuum cable shield.
If the In-Vacuum cable is found to be defective, replace the In-Vacuum cable.
Re-attach the BNC and In-Vacuum cables, and repeat this procedure starting at
Step 2, otherwise continue at step 8.

8 Connect the In-Vacuum Cable to the Feed-Through.
9 Verify electrical continuity from the center pin on the BNC connector of the
Feed-Through to the center pin on the un-terminated end of the In-Vacuum
cable.

10 Verify electrical isolation from the center pin to electrical ground (Feed-Throughbody).
If the Feed-Through/In-Vacuum cable system is found to be defective, look for
defective electrical contacts at the Feed-Through to In-Vacuum cable connection.
Repair or replace the Feed-Through as necessary. Re-attach the BNC and
In-Vacuum cables and repeat this procedure starting at step 2. Otherwise, continue
at step 11.

4 - 17

Q-pod Operating Manual

11 Connect the six-inch BNC cable to the Feed-Through and disconnect it from the
Q-pod.

12 Verify electrical continuity from the center pin of the Microdot connector on the
Feed-Through to the un-terminated end of the six-inch BNC cable.

13 Verify electrical isolation from the center pin to electrical ground (Feed-Throughbody).
If the Feed-Through/six-inch BNC cable system is found to be defective, look for
defective contacts at the Feed-Through to BNC cable connection. Repair or
replace the Feed-Through as necessary, re-attach the BNC cable to the XIU and
In-Vacuum cable to the Crystal head and repeat this procedure starting at step 2.
4.3.1.3 Sensor Head Or Monitor Crystal
Diagnostic Procedure
NOTE: The procedure is for use with front load style sensor heads.

1 Remove the Crystal Cover from the Sensor Head.
2 Refer to Figure 4-7 on page 4-15. Connect the Crystal Sensor Emulator to the
Sensor Head at Point C.


If the Crystal Fail message disappears after approximately 5 seconds the
Sensor Head is operating properly. Remove the Crystal Sensor Emulator
and re-insert the Crystal Cover into the Sensor Head.



If the Crystal Fail message remains, continue at step 3.

3 Disconnect the In-Vacuum cable from the Sensor Head and the Feed-Through.
Remove the Crystal Sensor Emulator from the Sensor Head.



Verify there is electrical continuity from the center pin contact on theMicrodot connector on the Sensor Head to the leaf spring contact in the
Sensor Head. Take care not to apply to much pressure on the center pin of
the microdot connector as it may become damaged.



There must be electrical isolation between the center pin of the Microdot
connector and the Sensor Head body.

If the Sensor Head is found to be defective, contact INFICON to have theSensor Head repaired.

4 - 18IPN 074-547-P1B

4 Using an Ohm meter, verify the electrical connections on the Sensor Head.

Q-pod Operating Manual

5 Connect the In-Vacuum Cable to the Sensor Head.


Verify there is continuity (<0.2 ohm) from the leaf spring contact in the
Sensor Head to the center pin on the un-terminated end of the In-Vacuum
cable.



Verify there is isolation (>10 megohm) between the leaf spring contact andthe In-Vacuum cable shield.

If the Sensor Head or the In-Vacuum cable system is found to be defective, look for
defective contacts at the In-Vacuum cable to Sensor Head connection, repair or
replace the Sensor Head as necessary. Re-attach the In-Vacuum cable to theFeed-Through and repeat this procedure starting at step 2.

6 Ensure that the leaf springs in the Sensor Head and those in the Ceramic
Retainer are bent to an angle of approximately 60º and 45º from flat,
respectively.
4.3.1.4 System Diagnostics Pass But
Crystal Fail Message Remains
If the system is operating properly yet the Crystal Fail message is still displayed,
perform the following tasks.

1 On the Ceramic Retainer verify that the center rivet is secure. Repair or replace
the Ceramic Retainer as necessary.

2 Inspect the inside of the Crystal Holder for build-up of material. Clean or replace

IPN 074-547-P1B

the Crystal Holder as necessary.
After verifying the Sensor Head contacts, the Sensor Head/In-Vacuum cableconnection and the ceramic retainer contacts, re-assemble the system. If the
Crystal Fail message remains, replace the monitor crystal with a new monitor
crystal. Verify that the monitor crystal works properly by inserting it into a known
good measurement system. If you continue to experience problems, contact
INFICON.

4 - 19Q-pod Operating Manual

4.3.2 Sensor Cover Connection
The Crystal Sensor Emulator can be used to verify the measurement system for
INFICON Thin Film Deposition Controllers and Monitors.
However, the Crystal Sensor Emulator's Sensor Cover Connector is compatible
with some sensor heads, and is incompatible with others. This is discussed in thefollowing sections.
4.3.2.1 Compatible Sensor Heads
The Sensor Cover Connection will fit the sensor heads shown in Table 4-4.
Table 4-4 Compatible Sensor Heads

Sensor HeadPart Number

Front Load Single Sensor Head

SL-XXXXX

Front Load Dual Sensor HeadDL-AEXX

4.3.2.2 Incompatible Sensor Heads
The Sensor Heads for which the Crystal Sensor Emulator's Sensor CoverConnector will not fit are shown in Table 4-5.
Sensor HeadPart Number

Front Load UHV Bakeable Sensor Head

BK-AXX

Cool Drawer Single Sensor Head

CDS-XXXXX

Sputtering Sensor Head

750-618-G1

CrystalSix Sensor Head

750-446-G1

Cool Drawer Dual Sensor Head

CDD-XXXX

Crystal12 Sensor Head

XL12-XXXXXX

RSH-600 Sensor Head

15320X-XX

NOTE: The Crystal Sensor Emulator’s Sensor Cover will not fit the crystal holder
opening of the older style INFICON transducers that have the solderedfinger springs.

4 - 20

IPN 074-547-P1B

Table 4-5 Incompatible Sensor Heads

Q-pod Operating Manual

4.3.3 Emulator Specifications
Dimensions
1.58 in. diameter x 1.79 in.
(40.13 mm diameter x 45.47 mm)
Temperature Range
0 to 50oC
Frequency
760-601-G2: 5.5 MHz ± 1 ppm at room temperature
Materials

IPN 074-547-P1B

304 Stainless Steel, Nylon, Teflon®, brass. Some internal components containzinc, tin, and lead.

4 - 21

Q-pod Operating Manual

IPN 074-547-P1B

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4 - 22

Q-pod Operating Manual

Chapter 5
Calibration Procedures
5.1 Importance of Density, Tooling and Z-Ratio
The quartz crystal microbalance is capable of precisely measuring the mass added
to the face of the oscillating quartz crystal sensor. The Q-pod's knowledge of thedensity of this added material (specified in the density parameter in material grid)
allows conversion of the mass information into thickness. In some instances, where
highest accuracy is required, it is necessary to make a density calibration as
outlined in section 5.2.
Because the flow of material from a deposition is not uniform, it is necessary to
account for the different amount of material flow onto the sensor compared to thesubstrates. This factor is accounted for in the tooling parameter in material grid.
The tooling factor can be experimentally established by following the guidelines in
section 5.3 on page 5-2.
If the Z-Ratio is not known, it could be estimated from the procedures outlined in
section 5.4 on page 5-2.

5.2 Determining Density
NOTE: The bulk density values retrieved from Table A-1 are sufficiently accurate
for most applications.
Follow the steps below to determine density value.

IPN 074-547-P1B

1 Place a substrate (with proper masking for film thickness measurement)
adjacent to the sensor, so that the same thickness will be accumulated on the
crystal and substrate.

2 Set density to the bulk value of the film material or to an approximate value.
3 Set Z-Ratio to 1.000 and tooling to 100%.
4 Place a new crystal in the sensor and make a short deposition(1000-5000 Å).

5 After deposition, remove the test substrate and measure the film thickness witheither a multiple beam interferometer or a stylus-type profilometer.

6 Determine the new density value with equation [1]:

 Tx 
3
Density  g  cm  = D 1  ------- T m

[1]5-1

Q-pod Operating Manual

where:
D1 = Initial density setting
Tx = Thickness reading on Q-pod
Tm = Measured thickness

7 A quick check of the calculated density may be made by programming the
Q-pod with the new density value and observing that the displayed thickness isequal to the measured thickness, provided that the Q-pod's thickness has notbeen zeroed between the test deposition and entering the calculated density.
NOTE: Slight adjustment of density may be necessary in order toachieve Tx = Tm.

5.3 Determining Tooling
1 Place a test substrate in the system's substrate holder.
2 Make a short deposition and determine actual thickness.
3 Calculate tooling from the relationship shown in equation [2]:

 T m
Tooling (%) = TF i  ------- Tx 

[2]

whereTm = Actual thickness at substrate holder
Tx = Thickness reading in the Q-pod

4 Round off percent tooling to the nearest 0.1%.
5 When entering this new value for tooling into the program, Tm will equal Tx if
calculations are done properly.

NOTE: It is recommended that a minimum of three separate evaporations be
made when calibrating tooling. Variations in source distribution and othersystem factors will contribute to slight thickness variations. An averagevalue tooling factor should be used for final calibrations.

5.4 Laboratory Determination of Z-Ratio
A list of Z-values for materials commonly used are available in Table A-1. For othermaterials, Z can be calculated from the following formula:5-2

IPN 074-547-P1B

TFi = Initial tooling factor

Q-pod Operating Manual

1-- d q  q 2

Z =  ------------ df f [3]

5

Z = 9.378  10  d f  f 

1
- --2

[4]

where:
df = density (g/cm3) of deposited film
µf = shear modulus (dynes/cm2) of deposited film
dq = density of quartz (crystal) (2.649 gm/cm3)µq = shear modulus of quartz (crystal) (3.32 x 1011 dynes/cm2)
The densities and shear moduli of many materials can be found in a number ofhandbooks.
Laboratory results indicate that Z-values of materials in thin-film form are very close
to the bulk values. However, for high stress producing materials, Z-values of thinfilms are slightly smaller than those of the bulk materials. For applications that
require more precise calibration, the following direct method is suggested:

1 Establish the correct density value as described in section 5.2 on page 5-1.
2 Install a new crystal and record its starting frequency, Fco. The starting
frequency will be displayed on the main screen.

IPN 074-547-P1B

3 Make a deposition on a test substrate such that the percent crystal life display
will read approximately 50%, or near the end of crystal life for the particularmaterial, whichever is smaller.

4 Stop the deposition and record the ending crystal frequency Fc.
5 Remove the test substrate and measure the film thickness with either a multiple
beam interferometer or a stylus-type profilometer.

6 Using the density value from step 1 and the recorded values for Fco and Fc,

adjust the Z-ratio value in thickness equation [5] to bring the calculated
thickness value into agreement with the actual thickness. If the calculated valueof thickness is greater than the actual thickness, increase the Z-Ratio value. If
the calculated value of thickness is less than the actual thickness, decrease the
Z-Ratio value.
4

Z q  10  1
F co
F c 
1
T f = --------------------   -------- ATan  zTan  -----------  –  ----- ATan  zTan  ---------   F q    F c
 Fq  
2zp   F co


[5]

5-3

Q-pod Operating Manual

where:
Tf = thickness of deposited film (kÅ)
Fco = starting frequency of the sensor crystal (Hz)Fc = Final frequency of the sensor crystal (Hz)Fq = Nominal blank frequency = 6045000 (Hz)z = Z-ratio of deposited film material
Zq = Specific acoustic impedance of quartz = 8765000 (MKS units)p = density of deposited film (g/cc)
For multiple layer deposition (for example, two layers), the Z-value used for thesecond layer is determined by the relative thickness of the two layers. For mostapplications the following three rules will provide reasonable accuracies:
If the thickness of layer 1 is large compared to layer 2, use material 1 Z-value
for both layers.



If the thickness of layer 1 is thin compared to layer 2, use material 2 Z-value forboth layers.



If the thickness of both layers is similar, use a value for Z-Ratio which is theweighted average of the two Z values for deposition of layer 2 and subsequent
layers.

IPN 074-547-P1B



5-4

Q-pod Operating Manual

Chapter 6
Measurement and Theory
6.1 Basics
The Quartz Crystal deposition Monitor, or QCM, utilizes the piezoelectric sensitivityof a quartz monitor crystal to added mass. The QCM uses this mass sensitivity tocontrol the deposition rate and final thickness of a vacuum deposition. When avoltage is applied across the faces of a properly shaped piezoelectric crystal, thecrystal is distorted and changes shape in proportion to the applied voltage. At
certain discrete frequencies of applied voltage, a condition of very sharp
electro-mechanical resonance is encountered. When mass is added to the face ofa resonating quartz crystal, the frequency of these resonances are reduced. Thischange in frequency is very repeatable and is precisely understood for specificoscillating modes of quartz. This heuristically easy to understand phenomenon isthe basis of an indispensable measurement and process control tool that can easily
detect the addition of less than an atomic layer of an adhered foreign material.
In the late 1950’s it was noted by Sauerbrey1,2 and Lostis3 that the change infrequency, DF = Fq-Fc, of a quartz crystal with coated (or composite) and uncoatedfrequencies, Fc and Fq respectively, is related to the change in mass from theadded material, Mf , as follows:MF -------f = ----------Mq
Fq[1]

IPN 074-547-P1B

where Mq is the mass of the uncoated quartz crystal. Simple substitutions lead tothe equation that was used with the first “frequency measurement” instruments: F -
Tf = K--------------df[2]

where the film thickness, Tf, is proportional (through K) to the frequency change,
DF, and inversely proportional to the density of the film, df. The constant, K =Natdq/Fq2; where dq (= 2.649 gm/cm3) is the density of single crystal quartz and Nat(=166100 Hz cm) is the frequency constant of AT cut quartz. A crystal with astarting frequency of 6.0 MHz will display a reduction of its frequency by 2.27 Hz
when 1 angstrom of Aluminum (density of 2.77 gm/cm3) is added to its surface. In
this manner the thickness of a rigid adlayer is inferred from the precise
measurement of the crystal’s frequency shift. The quantitative knowledge of this1.G. Z. Sauerbrey, Phys. Verhand .8, 193 (1957)
2.G. Z. Sauerbrey, Z. Phys. 155,206 (1959)
3.P. Lostis, Rev. Opt. 38,1 (1959)

6-1

Q-pod Operating Manual

effect provides a means of determining how much material is being deposited on asubstrate in a vacuum system, a measurement that was not convenient or practicalprior to this understanding.

6.1.1 Monitor Crystals
No matter how sophisticated the electronics surrounding it, the essential device ofthe deposition monitor is the quartz crystal. The quartz crystal shown in Figure 6-1
has a frequency response spectrum that is schematically shown in Figure 6-2. The
ordinate represents the magnitude of response, or current flow of the crystal, at the
specified frequency.

The lowest frequency response is primarily a “thickness shear” mode that is called
the fundamental. The characteristic movement of the thickness shear mode is fordisplacement to take place parallel to the major monitor crystal faces. In otherwords, the faces are displacement antinodes as shown in Figure 6-3. The
responses located slightly higher in frequency are called anharmonics; they are a
combination of the thickness shear and thickness twist modes. The response atabout three times the frequency of the fundamental is called the third
quasiharmonic. There are also a series of anharmonics slightly higher in frequency
associated with the quasiharmonic.
The monitor crystal design depicted in Figure 6-1 is the result of several significant
improvements from the square crystals with fully electroded plane parallel facesthat were first used. The first improvement was to use circular crystals. This
increased symmetry greatly reduced the number of allowed vibrational modes. The
second set of improvements was to contour one face of the crystal and to reduce
the size of the exciting electrode. These improvements have the effect of trapping
the acoustic energy. Reducing the electrode diameter limits the excitation to thecentral area. Contouring dissipates the energy of the traveling acoustic wave
before it reaches the edge of the crystal. Energy is not reflected back to the center
where it can interfere with other newly launched waves, essentially making a small
crystal appear to behave as though it is infinite in extent. With the crystal’s
vibrations restricted to the center, it is practical to clamp the outer edges of thecrystal to a holder and not produce any undesirable effects. Contouring also

6-2

IPN 074-547-P1B

Figure 6-1 Quartz ResonatorQ-pod Operating Manual

reduces the intensity of response of the generally unwanted anharmonic modes;
hence, the potential for an oscillator to sustain an unwanted oscillation issubstantially reduced.

1
10

6

7

17

18.133 MHz 350 ohm

17.957 MHz 311 ohm

17.792 MHz 278 ohm

6.419 MHz 350 ohm

6.333 MHz 142 ohm
6.337 MHz 105 ohm
6.348 MHz 322 ohm

11000

6.153 MHz 50 ohm
6.194 MHz 40 ohm

1100
5.981 MHz 15 ohm

Log of relative intensity (Admittance)

Figure 6-2 Frequency Response Spectrum

18

Frequency (in MHz)IPN 074-547-P1B

The use of an adhesion layer has improved the electrode-to-quartz bonding,
reducing “rate spikes” caused by micro-tears between the electrode and the quartz
as film stress rises. These micro-tears leave portions of the deposited film
unattached and therefore unable to participate in the oscillation. These free
portions are no longer detected and the wrong thickness consequently inferred.
The “AT” resonator is usually chosen for deposition monitoring because at room
temperature it can be made to exhibit a very small frequency change due totemperature changes. Since there is presently no way to separate the frequencychange caused by added mass (which is negative) or even the frequency changes
caused by temperature gradients across the crystal or film induced stresses, it isessential to minimize these temperature-induced changes. It is only in this way that
small changes in mass can be measured accurately.

6-3

Q-pod Operating Manual
Figure 6-3 Thickness Shear Displacement

E

X2

displacement node

X
1
X
3

6.1.2 Period Measurement Technique
Although instruments using equation [2] were very useful, it was soon noted they
had a very limited range of accuracy, typically holding accuracy for DF less than
0.02 Fq. In 1961 it was recognized by Behrndt4 that:[3]

where Tc and Tq are the periods of oscillation of the crystal with film (composite)
and the bare crystal respectively. The period measurement technique was theoutgrowth of two factors; first, the digital implementation of time measurement, andsecond, the recognition of the mathematically rigorous formulation of the
proportionality between the crystal’s thickness, Iq, and the period of oscillation, Tq= 1/Fq. Electronically the period measurement technique uses a second crystal
oscillator, or reference oscillator, not affected by the deposition and usually muchhigher in frequency than the monitor crystal. This reference oscillator is used togenerate small precision time intervals which are used to determine the oscillation
period of the monitor crystal. This is done by using two pulse accumulators. The
first is used to accumulate a fixed number of cycles, m, of the monitor crystal. The
second is turned on at the same time and accumulates cycles from the reference
oscillator until m counts are accumulated in the first. Since the frequency of thereference is stable and known, the time to accumulate the m counts is known to an
accuracy equal to ± 2/Fr where Fr is the reference oscillator’s frequency. The

4.K. H. Behrndt, J. Vac. Sci. Technol. 8, 622 (1961)

6-4

IPN 074-547-P1B

M Tc – Tq  F 
-------f = ---------------------= ----------Tq
Mq
Fc

Q-pod Operating Manual

monitor crystal’s period is (n/Fr)/m where n is the number of counts in the second
accumulator. The precision of the measurement is determined by the speed of thereference clock and the length of the gate time (which is set by the size of m).
Increasing one or both of these leads to improved measurement precision.
Having a high frequency reference oscillator is important for rapid measurements(which require short gating times), low deposition rates and low density materials.
All of these require high time precision to resolve the small, mass induced
frequency shifts between measurements. When the change of a monitor crystal’sfrequency between measurements is small, that is, on the same order of size as
the measurement precision, it is not possible to establish quality rate control. The
uncertainty of the measurement injects more noise into the control loop, which canbe counteracted only by longer time constants. Long time constants cause thecorrection of rate errors to be very slow, resulting in relatively long term deviations
from the desired rate. These deviations may not be important for some simple films,
but can cause unacceptable errors in the production of critical films such as opticalfilters or very thin layered superlattices grown at low rates. In many cases thedesired properties of these films can be lost if the layer to layer reproducibility
exceeds one, or two, percent. Ultimately, the practical stability and frequency of thereference oscillator limits the precision of measurement for conventional
instrumentation.

IPN 074-547-P1B

6.1.3 Z-match Technique
After learning of fundamental work by Miller and Bolef 5, which rigorously treatedthe resonating quartz and deposited film system as a one-dimensional continuous
acoustic resonator, Lu and Lewis6 developed the simplifying Z-match™ equationin 1972. Advances in electronics taking place at the same time, namely the
micro-processor, made it practical to solve the Z-match equation in “real-time”.
Most deposition process controllers/monitors sold today use this sophisticatedequation that takes into account the acoustic properties of the resonating quartz
and film system as shown in equation [4].

N at d q  Fq – Fc 
T f =  ------------------ arctan  Z tan ------------------------- d f F c Z
Fq[4]

where Z=(dquq/dfuf)1/2 is the acoustic impedance ratio and uq and uf are the shear
moduli of the quartz and film, respectively. Finally, there was a fundamental
understanding of the frequency-to-thickness conversion that could yieldtheoretically correct results in a time frame that was practical for process control.
To achieve this new level of accuracy requires only that the user enter an additional
material parameter, Z, for the film being deposited. This equation has been tested

5.J. G. Miller and D. I. Bolef, J. Appl. Phys. 39, 5815, 4589 (1968)
6.C. Lu and O. Lewis, J Appl. Phys. 43, 4385 (1972)

6-5

Q-pod Operating Manual

for a number of materials, and has been found to be valid for frequency shifts
equivalent to Ff = 0.4Fq. Keep in mind that equation [2] was valid to only 0.02Fq
and equation [3] was valid only to ~0.05Fq.

6.1.4 Active Oscillator
The Q-pod relies on the use of an active oscillator circuit, Specifically the typeschematically shown in Figure 6-4. This circuit actively keeps the crystal inresonance, so that any type of period or frequency measurement may be made. In
this type of circuit, oscillation is sustained as long as the gain provided by the
amplifiers is sufficient to offset losses in the crystal and circuit and the crystal can
provide the required phase shift. The basic crystal oscillator’s stability is derived
from the rapid change of phase for a small change in the crystal’s frequency near
the series resonance point, as shown in Figure 6-6 on page 6-7.

The active oscillator circuit is designed so the crystal is required to produce a phaseshift of 0 degrees, which allows it to operate at the series resonance point. Longand short-term frequency stabilities are a property of crystal oscillators becausevery small frequency changes are needed to sustain the phase shift required foroscillation. Frequency stability is provided by the quartz crystal even though there
are long term changes in electrical component values caused by temperature or
aging or short-term noise-induced phase jitter.
As mass is added to a crystal, its electrical characteristics change. Figure 6-5 onpage 6-7 is the same plot as Figure 6-6 overlaid with the response of a heavily
loaded crystal.

6-6

IPN 074-547-P1B

Figure 6-4 Active Oscillator CircuitQ-pod Operating Manual
Figure 6-5 Heavily Loaded Crystal

The crystal has lost the steep slope displayed in Figure 6-6. Because the phaseslope is less steep, any noise in the oscillator circuit translates into a greater
frequency shift than that which would be produced with a new crystal. In theextreme, the basic phase/frequency shape is not preserved and the crystal is notable to provide a full 90 degrees of phase shift.

IPN 074-547-P1B

Figure 6-6 Crystal Frequency Near Series Resonance Point

The impedance, |Z|, is also noted to rise to an extremely high value. When thishappens it is often more favorable for the oscillator to resonate at one of theanharmonic frequencies. This condition is sometimes short lived, with the oscillator
switching between the fundamental and anharmonic modes, or it may continue tooscillate at the anharmonic. This condition is known as mode hopping and in
addition to annoying rate noise can also lead to false termination of the film
because of the apparent frequency change. It is important to note that the Q-pod
will frequently continue to operate under these conditions; in fact there is no way totell this has happened except that the film’s thickness is suddenly apparently
thinner by an amount equivalent to the frequency difference between thefundamental and the anharmonic that is sustaining the oscillation.

6-7

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6-8Q-pod Operating Manual

Appendix A
Material Table
A.1 Introduction
The following Table A-1 represents the density and Z-Ratio for various materials.
The list is alphabetical by chemical formula.

CAUTION
Some of these materials are toxic. Please consult thematerial safety data sheet and safety instructions beforeuse.
An * is used to indicate that a Z-ratio has not been established for a certain
material. A value of 1.000 is defaulted in these situations.

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Table A-1 Material Table

FormulaDensity

Z-Ratio

Material Name

Ag

10.5000.529

silver

AgBr

6.470

1.180

silver bromide

AgCl

5.560

1.320

silver chloride

Al

2.700

1.080

aluminum

Al2O3

3.970

0.336

aluminum oxide

Al4C3

2.360

*1.000aluminum carbide

AIF3

3.070

*1.000aluminum fluoride

AIN

3.260

*1.000aluminum nitride

AlSb

4.360

0.743

aluminum antimonide

As

5.730

0.966

arsenic

As2Se34.750*1.000arsenic selenideAu

19.300

0.381

gold

B

2.370

0.389

boron

B 20 31.820*1.000boron oxide

B 4C

2.370

*1.000boron carbide

BN

1.860

*1.000boron nitride

Ba

3.500

2.100

barium

BaF2

4.886

0.793

barium fluoride

PRELIMINARY 5/4/12

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Q-pod Operating Manual

A-2

FormulaDensity

Z-Ratio

Material NameBaN2O6

3.244

1.261

barium nitrate

BaO

5.720

*1.000barium oxide

BaTiO3

5.999

0.464

barium titanate (tetr)

BaTiO3

6.035

0.412

barium titanate (cubic)

Be

1.850

0.543

beryllium

BeF2

1.990

*1.000beryllium fluoride

BeO

3.010

*1.000beryllium oxide

Bi

9.800

0.790

bismuth

Bi2O3

8.900

*1.000

bismuth oxide

Bi2S3

7.390

*1.000

bismuth trisulphide

Bi2Se36.820*1.000

bismuth selenide

Bi2Te37.700*1.000

bismuth telluride

BiF3

5.320

*1.000

bismuth fluoride

C

2.250

3.260

carbon (graphite)

C

3.520

0.220

carbon (diamond)C 8H 81.100*1.000parlyene (union carbide)

Ca

1.550

2.620

calcium

CaF2

3.180

0.775

calcium fluoride

CaO

3.350

*1.000calcium oxide

CaO-SiO2

2.900*1.000calcium silicate (3)

CaSO4

2.962

0.955

calcium sulfate

CaTiO34.100*1.000calcium titanate

CaWO4

6.060

*1.000calcium tungstate

Cd

8.640

0.682

cadmium

CdF2

6.640

*1.000

cadmium fluoride

CdO

8.150

*1.000

cadmium oxide

CdS

4.830

1.020

cadmium sulfide

CdSe

5.810

*1.000

cadmium selenide

CdTe

6.200

0.980

cadmium telluride

Ce

6.780

*1.000cerium

CeF3

6.160

*1.000cerium (III) fluoride

CeO2

7.130

*1.000cerium (IV) dioxide

Co

8.900

0.343

cobalt

IPN 074-547-P1B

Table A-1 Material Table (continued)

PRELIMINARY 5/4/12

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IPN 074-547-P1B

Table A-1 Material Table (continued)

FormulaDensity

Z-Ratio

Material Name

CoO

6.440

0.412

cobalt oxide

Cr

7.200

0.305

chromium

Cr2O3

5.210

*1.000chromium (III) oxide

Cr3C2

6.680

*1.000chromium carbide

CrB

6.170

*1.000chromium boride

Cs

1.870

*1.000cesium

Cs2SO4

4.243

1.212

cesium sulfate

CsBr

4.456

1.410

cesium bromide

CsCI

3.988

1.399

cesium chloride

CsI

4.516

1.542

cesium iodide

Cu

8.930

0.437

copper

Cu2O

6.000

*1.000copper oxide

Cu2S

5.600

0.690

copper (I) sulfide (alpha)

Cu2S

5.800

0.670

copper (I) sulfide (beta)

CuS

4.600

0.820

copper (II) sulfide

Dy

8.550

0.600

dysprosium

DY2O3

7.810

*1.000dysprosium oxide

Er

9.050

0.740

erbium

Er2O3

8.640

*1.000erbium oxide

Eu

5.260

*1.000europium

EuF2

6.500

*1.000europium fluoride

Fe

7.860

0.349

iron

Fe2O3

5.240

*1.000iron oxide

FeO

5.700

*1.000iron oxide

FeS

4.840

*1.000iron sulphide

Ga

5.930

0.593

gallium

Ga2O3

5.880

*1.000gallium oxide (b)

GaAs

5.310

1.590

gallium arsenide

GaN

6.100

*1.000gallium nitride

GaP

4.100

*1.000gallium phosphide

GaSb

5.600

*1.000gallium antimonide

Gd

7.890

0.670

gadolinium

Gd2O3

7.410

*1.000gadolinium oxide

PRELIMINARY 5/4/12

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Q-pod Operating Manual

A-4

FormulaDensity

Z-Ratio

Material Name

Ge

5.350

0.516

germanium

Ge3N2

5.200

*1.000germanium nitride

GeO2

6.240

*1.000germanium oxide

GeTe

6.200

*1.000germanium tellurideHf

13.0900.360

hafnium

HfB2

10.500*1.000hafnium boride

HfC

12.200*1.000hafnium carbide

HfN

13.800*1.000hafnium nitride

HfO2

9.680

*1.000hafnium oxide

HfSi2

7.200

*1.000hafnium silicideHg

13.4600.740

mercury

Ho

8.800

0.580

holminum

Ho2O3

8.410

*1.000holminum oxide

In

7.300

0.841

indium

In2O3

7.180

*1.000

indiurn sesquioxide

In2Se35.700*1.000

indium selenide

In2Te35.800*1.000

indium telluride

InAs

5.700

*1.000

indium arsenide

InP

4.800

*1.000

indium phosphide

InSb

5.760

0.769

indium antimonide

Ir

22.4000.129

iridiumK

0.860

10.189potassium

KBr

2.750

1.893

potassium bromide

KCI

1.980

2.050

potassium chloride

KF

2.480

*1.000potassium fluoride

KI

3.128

2.077

potassium iodide

La

6.170

0.920

lanthanum

La2O3

6.510

*1.000lanthanum oxide

LaB6

2.610

*1.000lanthanurn boride

LaF3

5.940

*1.000lanthanum fluoride

Li

0.530

5.900

lithium

LiBr

3.470

1.230

lithium bromide

LiF

2.638

0.778

lithium fluoride

IPN 074-547-P1B

Table A-1 Material Table (continued)

PRELIMINARY 5/4/12

Q-pod Operating Manual

IPN 074-547-P1B

Table A-1 Material Table (continued)

FormulaDensity

Z-Ratio

Material Name

LiNbO3

4.700

0.463

lithium niobate

Lu

9.840

*1.000lutetium

Mg

1.740

1.610

magnesium

MgAl2O4

3.600*1.000magnesium aluminate

MgAl2O6

8.000*1.000spinel

MgF2

3.180

0.637

magnesium fluoride

MgO

3.580

0.411

magnesium oxide

Mn

7.200

0.377

manganese

MnO

5.390

0.467

manganese oxide

MnS

3.990

0.940

manganese (II) sulfide

Mo

10.2000.257

molybdenum

Mo2C

9.180

*1.000molybdenum carbide

MoB2

7.120

*1.000molybdenum boride

MoO3

4.700

*1.000molybdenum trioxdide

MoS2

4.800

*1.000molybdenum disulfide

Na

0.970

4.800

sodiumNa3AIF6

2.900*1.000cryolite

Na5Al3F14

2.900*1.000chiolite

NaBr

3.200

*1.000sodium bromide

NaCl

2.170

1.570

sodium chloride

NaCIO3

2.164

1.565

sodium chlorate

NaF

2.558

1.645

sodium fluoride

NaNO3

2.270

1.194

sodium nitrate

Nb

8.578

0.492

niobium (columbium)

Nb2O3

7.500

*1.000niobium trioxide

Nb2O5

4.470

*1.000niobium (V) oxide

NbB2

6.970

*1.000niobium boride

NbC

7.820

*1.000niobium carbide

NbN

8.400

*1.000niobium nitride

Nd

7.000

*1.000neodynium

Nd2O3

7.240

*1.000neodynium oxide

NdF3

6.506

*1.000neodynium fluoride

Ni

8.910

0.331

nickelPRELIMINARY 5/4/12

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Q-pod Operating Manual

A-6

FormulaDensity

Z-Ratio

Material Name

NiCr

8.500

*1.000nichrome

NiCrFe8.500*1.000inconel

NiFe

8.700

*1.000permalloy

NiFeMo8.900*1.000supermalloy

NiO

7.450

*1.000nickel oxide

P 3N 52.510*1.000phosphorus nitridePb

11.300

1.130

lead

PbCl2

5.850

*1.000lead chloride

PbF2

8.240

0.661

lead fluoride

PbO

9.530

*1.000lead oxide

PbS

7.500

0.566

lead sulfide

PbSe

8.100

*1.000lead selenide

PbSnO38.100*1.000lead stannate

PbTe

8.160

0.651

lead telluridePd

12.0380.357

palladium

PdO

8.310

*1.000palladium oxide

Po

9.400

*1.000polonium

Pr

6.780

*1.000praseodymium

Pr2O3

6.880

*1.000praseodymium oxidePt21.4000.245

platinum

PtO2

10.200*1.000

platinum oxide

Ra

5.000

*1.000radium

Rb

1.530

2.540

rubidium

RbI

3.550

*1.000rubidiurn iodide

Re

21.0400.150

rheniumRh

12.4100.210

rhodiumRu

12.362

0.182

ruthenium

S8

2.070

2.290

sulphur

Sb

6.620

0.768

antimony

Sb2O3

5.200

*1.000antimony trioxide

Sb2S3

4.640

*1.000antimony trisulfide

Sc

3.000

0.910

scandium

Sc2O3

3.860

*1.000scandium oxide

IPN 074-547-P1B

Table A-1 Material Table (continued)

PRELIMINARY 5/4/12

Q-pod Operating Manual

IPN 074-547-P1B

Table A-1 Material Table (continued)

FormulaDensity

Z-Ratio

Material Name

Se

4.810

0.864

selenium

Si

2.320

0.712

silicon

Si3N4

3.440

*1.000silicon nitride

SiC

3.220

*1.000silicon carbide

SiO

2.130

0.870

silicon (ii) oxide

SiO2

2.648

1.000

silicon dioxide

Sm

7.540

0.890

samarium

Sm2O3

7.430

*1.000samarium oxide

Sn

7.300

0.724

tin

SnO2

6.950

*1.000tin oxide

SnS

5.080

*1.000tin sulfide

SnSe

6.180

*1.000tin selenide

SnTe

6.440

*1.000tin telluride

Sr

2.600

*1.000strontium

SrF2

4.277

0.727

strontium fluroide

SrO

4.990

0.517

strontium oxide

Ta16.6000.262

tantalum

Ta2O5

8.200

0.300

tantalum (v) oxide

TaB2

11.150*1.000tantalum boride

TaC

13.900*1.000tantalum carbide

TaN

16.300*1.000tantalum nitride

Tb

8.270

0.660

terbiumTc

11.500*1.000technetium

Te

6.250

0.900

tellurium

TeO2

5.990

0.862

tellurium oxideTh

11.694

0.484

thorium

ThF4

6.320

*1.000thorium.(IV) fluoride

ThO2

9.860

0.284

thorium dioxide

ThOF2

9.100

*1.000thorium oxyfluoride

Ti

4.500

0.628

titanium

Ti203

4.600

*1.000titanium sesquioxide

TiB2

4.500

*1.000titanium boride

TiC

4.930

*1.000titanium carbide

PRELIMINARY 5/4/12

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Q-pod Operating Manual

A-8

FormulaDensity

Z-Ratio

Material Name

TiN

5.430

*1.000titanium nitride

TiO

4.900

*1.000titanium oxide

TiO2

4.260

0.400

titanium (iv) oxide

TI

11.8501.550

thallium

TIBr

7.560

*1.000thallium bromide

TICI

7.000

*1.000thallium chloride

TII

7.090

*1.000thalliurn iodide (b)U

19.0500.238

uranium

U 3O 88.300*1.000

tri uranium octoxide

U 4O 910.9690.348

uranium oxide

UO2

10.970

0.286

uranium dioxide

V

5.960

0.530

vanadium

V 2O 53.360*1.000

vanadium pentoxide

VB2

5.100

*1.000

vanadium boride

VC

5.770

*1.000

vanadium carbide

VN

6.130

*1.000

vanadium nitride

VO2

4.340

*1.000

vanadium dioxide

W19.3000.163

tungsten

WB2

10.770*1.000tungsten borideWC

15.6000.151

tungsten carbide

WO3

7.160

*1.000tungsten trioxide

WS2

7.500

*1.000tungsten disulphide

WSi2

9.400

*1.000tungsten silicide

Y

4.340

0.835

yttrium

Y 20 35.010*1.000yttrium oxide

Yb

6.980

1.130

ytterbium

Yb2O3

9.170

*1.000ytterbium oxide

Zn

7.040

0.514

zinc

Zn3Sb26.300*1.000zinc antimonide

ZnF2

4.950

*1.000zinc fluoride

ZnO

5.610

0.556

zinc oxide

ZnS

4.090

0.775

zinc sulfide

ZnSe

5.260

0.722

zinc selenide

IPN 074-547-P1B

Table A-1 Material Table (continued)

PRELIMINARY 5/4/12

Q-pod Operating Manual
Table A-1 Material Table (continued)

Density

Z-Ratio

Material Name

ZnTe

6.340

0.770

zinc telluride

Zr

6.490

0.600

zirconium

ZrB2

6.080

*1.000zirconium boride

ZrC

6.730

0.264

zirconium carbide

ZrN

7.090

*1.000zirconium nitride

ZrO2

5.600

*1.000zirconium oxide

IPN 074-547-P1B

FormulaPRELIMINARY 5/4/12

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IPN 074-547-P1B

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A - 10PRELIMINARY 5/4/12