APPLICATION NOTETRANSFER CHAMBER MONITORING
200mm and 300mm PVD Cluster Tools
Integrated Process Metrology (IPM) utilizes in situ sensors toprovide process data in real time. This data can be used tofingerprint process conditions, identify process faults, pinpoint
problems, and tune recipes for greater yield.

Signal bins are normalized so that they remain consistent overtime. By implementing a partial pressure contribution to thechamber, signal bins are shown as a percentage of the total
and therefore are independent of sensor variance over time.

Transfer chamber monitoring is one of the easiest and least
expensive ways to implement IPM, using a Residual Gas
Analyzer (RGA) for monitoring process chemistries and contamination. This IPM employs an open-source RGA mounted
on the transfer chamber which is connected to the FabGuard®
Analysis System. Sensor operation is integrated with production tool operation (communicating with FabGuard via SECSor HSMS), allowing a single RGA to monitor the transfer
chamber for hydrocarbon contamination and air leaks, andeach individual process chamber for any pump down.

To create chamber specific signal bins, tool data for slit valve
position and logical expressions are combined to build a signalthat only exists when all other process chambers are isolated
and one is open. This way there is no question as to wherethe signals originated.

SYSTEM CONFIGURATIONThe RGA Recipe is set up to acquire the appropriate tool IDs
so that FabGuard can determine which chambers are openingand closing. Some of these IDs include:• Process chamber slit valves• Transfer chamber pressure gauges• Cryopump stage temperatures• Slit valves to chamber A and cool B

APPLICATION EXAMPLES
Leak and Cross Contamination Detection
The most common contamination source in PVD cluster tools
is an air leak. An air leak in the transfer chamber will cause
the freshly exposed surface of wafers arriving from the sputter
clean to be introduced to water residuals that can affect film
properties. This same air leak can then contaminate the process chambers, which are not only sensitive to water, but may
also be susceptible to oxidation of metal depositions. The
high sensitivity of the RGA detects air leaks originating in theprocess chamber when slit valves are open. Figure 1 shows
an example of an RGA on a transfer chamber detecting an air
leak in a PVD process chamber with FabGuard.

The recipe is then set up with signal bins much like the ones
used on a process chamber. These signal bins include
selections such as:• Normalized partial pressures of common gases andcontaminants for the transfer as well as each processchamber and chambers A/B• Transfer chamber cryopump health and pumping
efficiency• RGA diagnostics such as signal-to-noise levels andsensitivity

Typical Species Monitored:
✓✓
✓

Argon
Oxygen/AirWater✓✓✓

MethaneAmmonia
Total Hydrocarbons

Figure 1 - Leak discovered in process chamber

A process chamber can contaminate a transfer chamber, since
all chambers are interconnected. In a cluster tool, process
gasses themselves can be considered contamination if they
are transported to other process chambers. One such case, on
a cluster tool with TiN CVD and PVD chambers, is shown in
Figure 2. A single RGA with FabGuard discovered and helped
to resolve multiple problems. The first problem was CVD
process gasses back-streaming into the transfer chamber andthen on to other process chambers. The second problem wascreated when large amounts of hydrogen saturated the transfer chamber cryopump causing it to prematurely lose pumping
efficiency. Both problems were resolved by increasing thepump down time in the CVD chamber before wafer transport.

Preventive Maintenance Recovery
Preventive maintenance is a necessary part of manufacturing that leads to nonproductive tool time during component
replacement and cleaning, as well as chamber pump down
and recovery. With a specific preventive maintenance recovery
recipe, an IPM for the transfer chamber can monitor partialpressures and ratios of gas components, providing instantindication of potential problems before the tool takes the timeto try and reach baseline pressure goals. This saves valuable
operation time. During a normal pump down, the IPM can beused to indicate and optimize when the chamber is ready foroperation.

IPM for Transfer Chamber Monitoring
Capabilities At A Glance
Fully automated operation
Air leak detection
Cross contamination detection
Cryopump performance
Faster PM recovery
Flex-logic signal conditioning
Multi-functional data analysis• Real time analysis• SPC analysis✓ SQL searchable database✓ Hardware: H100M and IPM Controllerwith FabGuard✓✓✓✓✓✓✓

Applicable Tool Configurations
Figure 2 - H2 and Hydrocarbon Contamination✓ AMAT 200mm Endura

Cryopump Performance✓ AMAT 300mm Endura

A cryopump is an essential component of a transfer chamber.
An IPM for the transfer chamber can be used to monitor thepartial pressures of hydrogen and helium. By combining thisdata with tool data of the cryopump’s first and second stage
temperatures, the software can track the pump degradation tohelp operators choose optimum times for regenerations. Thishelps to streamline preventive maintenance schedules andavoid unplanned downtime due to component failure.

✓ Novellus 200mm INOVA✓ Novellus 300mm INOVA✓ ULVAC 200mm Ceraus Zx-1000✓ ULVAC 300mm Entron✓ Unaxis 300mm Clusterline✓Other possible tools utilizing low
pressure Transfer Chambers

GLOBAL HEADQUARTERS:
Two Technology Place, East Syracuse, NY 13057 USA
Tel: +1.315.434.1100 Fax: +1.315.437.3803 E-mail: reachus@inficon.com
UNITED STATESFRANCEGERMANY

LIECHTENSTEINSWITZERLAND

Visit our website for sales of fices wor ldwide. www.inficon.com
oiac65a1©2005 INFICON

UNITED KINGDOMCHINAJAPANKOREASINGAPORE

TAIWAN