Lake Shore CRX-EM-HF User manual

Lake Shore Cryotronics, Inc. 575 McCorkle Blvd Westerville, Ohio 43082
Tel: [phone] Fax: [phone] e-mail: [email protected] www.lakeshore.com
1
CRX-EM-HF Probe Station Instructions
Introduction
The Lake Shore Model CRX-EM-HF probe station combines the magnetic field capability of the Model EMPX-HF
probe station with the cryogen free capability of the model CRX-4K. The CRX-EM-HF is for non-destructive testing
of devices on full and partial wafers up to 25mm (1 in) in diameter. Based on a two-stage Gifford McMahon closed
cycle refrigerator (CCR), the CRX-EM-HF provides up to a ±0.6 T magnetic field over a temperature range of <8 K to
400 K standard or <20 K to 500 K with optional PS-HTA-EM high temperature stage.
Figure 1: CRX-EM-HF probe station
Rev 1.1 P/N 119-510 March 24, 2014

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Outline
The user’s manual for the new Lake Shore Model CRX-EM-HF probe station is not yet complete; however, the
standard CRX-4K and EMPX-HF user manuals have been included with your CRX-EM-HF probe station. This
document summarizes operation of the CRX-EM-HF and will be the guide for how to reference the CRX-4K and
EMPX-HF manuals. In the cases where the specifications, restrictions, or performance limitations are different
between the CRX-EM-HF and the CRX-4K/EMPX-HF, those listed in this document supersede the other manuals.
Lake Shore contact information for technical assistance can be found at the end of this document.
The sections in this document are as follows:
Specifications
System Overview
Installation and Setup
Vacuum, Probing, and Sample Operation
Temperature Operation
Magnetic Field Operation
Advanced Operation
Maintenance and Troubleshooting

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Specifications
Sample cooling assembly:
Type: 2-stage (sample + radiation shield)
Radiation shielding: Radiation shield with top viewport surrounds sample
Cooling source: 2-stage closed cycle refrigerator (CCR) with 1 W cooling power at
4.2 K
Temperature:
Standard range: 8 K to 400 K
Optional range 20 K to 500 K (PS-HTA-EM)
Vacuum: 10-5 Torr at base temperature
Cycle time: 4.5 h
Vacuum pump down: 0.5 h
Station cooldown: 2.25 h
Station warmup: 1.75 h
Vibration at sample: <1 µm
Sample:
Maximum sample size: 25.4 mm (1 in) diameter
Sample backside optical access: Not an option
Sample rotation: Optional 360 degree rotation stage (PS-360-CRX-EM)
Adds 2 K gradient from sample stage to top of rotation stage at
base temperature
Probing:
Maximum number of probes: 4 (see orientation diagram)
Cooled probe mounts: <20 K with sample at base temperature
DC/RF probes: Electrical isolation >100 Gfor low leakage measurements
Microwave probes: Frequency range DC up to 67 GHz
Fiber optic probes: Available for electro-optical measurements
Magnetic field:
Field capability: ±0.6 T
Field orientation: Horizontal (parallel to the sample plane)
Load lock: Not an option
High Vacuum: Not an option

Lake Shore Cryotronics, Inc. 575 McCorkle Blvd Westerville, Ohio 43082
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System Overview
Refer to Chapters 1 and 2 of the CRX-4K manual for general information about the CCR-based cryogenic probe
station and the available optional equipment that may be used with the CCR probe station. Refer to Chapters 1
and 2 of the EMPX-HF manual for general information about the electromagnet and for additional sample holders
or probe options: the components used in the CRX-EM-HF sample space must be non-magnetic.
Figure 2 shows the control elements of the CRX-EM-HF probe station.
Figure 2: CRX-EM-HF probe station overview (electronics console and CCR compressor not shown)
Optics package
and vision system
Purge Valve for
Venting Chamber
Vacuum Isolation
Valve
Probe Arm
Control (4x)
Vibration Isolation
Feet
Rotation Control
(Optional)

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Installation and Setup
This section describes the process of preparing a site, unpacking the probe station components and assembling
them into the standard CRX-EM-HF configuration. Finally, it explains system checkout procedures. The installation
and setup requirements of the CRX-EM-HF are a combination of the CCR requirements of the CRX-4K and the
electromagnet requirements of the EMPX-HF.
Site Requirements
Refer to section 3.2 of the CRX-4K manual for site requirements pertaining to the instrument console, CCR, and
CCR compressor. Refer to section 3.2.3 and section 3.2.4 of the EMPX-HF manual for site requirements for the
electromagnet, Model 475 gauss meter, and the Model 643 electromagnetic power supply. Requirements for the
Model 643 electromagnetic power supply are identical to the Model 642.
Unpacking the Probe Station
Refer to Chapter 3.3 of the CRX-4K manual as a guide to uncrating and unpacking the probe station. The CRX-EM-
HF weighs approximately 815 kg (1800 lbs); refer to section 3.3.4 of the CRX-4K manual for important safety
information when moving the probe station.
Utility Connections
Refer to section 3.4 of the CRX-4K manual for utility connections pertaining to the instrument console, CCR, and
CCR compressor. Refer to section 3.4.2 and section 3.4.3 of the EMPX-HF manual for utility connections for the
electromagnet and the Model 643 electromagnetic power supply.
Assembling a Basic Probe System Configuration
Complete all of the sections in section 3.5 of the CRX-4K manual for assembly of the probe station. You will also
need to complete steps 3-5 of section 3.5.1 of the EMPX-HF manual.
Installing and Removing Probes
Refer to section 3.6 of the EMPX-HF manual for instructions on installing and removing probes
Re-configuring the Sample Stage: Optional 360° Rotation Stage (PS-360-EMPX)
The CRX-EM-HF comes standard with the sample stage fixed adapter, or it can be configured with the sample stage
rotation option. The configuration is determined by the type of sample stage adapter that is attached to the
sample stage. If ordered, the rotation option will be installed in the CRX-EM-HF and includes the removable
rotation adapter and the rotation control drive that is integrated into the CRX-EM-HF probe station. The drive and
control remain in place even when the rotation adapter is removed.

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Removing the Sample Stage Rotation Option
1. Remove the vacuum chamber lid, radiation shield lid, and any installed probes. Fully retract any probe
arms (Figure 3).
Figure 3: CRX-EM-HF with rotation stage (vacuum chamber lid and radiation shield lid removed)
2. Using a 3 mm hex driver, loosen the four M4 rotation adapter captive screws.
3. Carefully lift the rotation adapter out of the probe station. Take care not to damage to the cryogenic
coaxial wire (Figure 4).
Figure 4: Removing the sample holder tower
Installing the Sample Stage Rotation Option
1. Remove the vacuum chamber lid, radiation shield lid, and any installed probes. Fully retract any probe
arms.
2. Lower the rotation adapter into the chamber. Take care not to damage to the cryogenic coaxial wire.
3. Align the rotation adapter to the drive shaft. The rotation option control knob may be turned to align the
square drive of the drive shaft to the rotation stage (Figure 6).
4. Using a 3 mm hex driver, fasten the rotation adapter to the sample stage by starting all four M4 screws in
a few threads before tightening any screws to prevent cross-threading.

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5. Tighten the four screws securely; this is the source of thermal contact between the rotation stage and the
sample stage. It is best to tighten all four screws a little at a time until snug.
6. Turn the rotation control knob on the probe station to verify that the rotation stage is functioning
smoothly.
Removing the Sample Stage Fixed Adapter
To remove the sample stage fixed adapter, follow the same procedure as outlined for removal of the rotation stage
option.
Figure 5: CRX-EM-HF with fixed stage (vacuum chamber lid and radiation shield lid removed)
Installing the Sample Stage Fixed Adapter
To install the sample stage fixed adapter, follow the same procedure as outlined for installation of the rotation
stage option, skipping step 3.
System Verification and Testing
Complete all sections of section 3.7 of the CRX-4K manual to verify that the probe station has been assembled
correctly and is in good working order. Refer to section 3.7.2 of the CRX-4K manual for temperature sensor and
heater verification testing instructions for the CRX-EM-HF; however, use the information in Table 4 and Table 5 of
this document instead of the controller settings listed in the CRX-4K manual. Refer to section 3.8.3 of the EMPX-HF
manual for electromagnet verification testing instructions for the CRX-EM-HF. The settings for the Model 475 gauss
meter and the Model 643 electromagnetic power supply are identical to those of the EMPX-HF. The settings are
found in Table 4-7 and Table 4-8 of the EMPX-HF manual, respectively.

Lake Shore Cryotronics, Inc. 575 McCorkle Blvd Westerville, Ohio 43082
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Basic Operation
Temperature Limits
The maximum temperature limits for the multiple stages and components of the probe station are listed below.
Adhere to these limits at all times during probe station operation.
Sample stage:
400 K
Radiation shield stage:
350 K
Cryocooler first stage:
300 K
Cryocooler second stage:
300 K
Probe arms:
350 K
Vacuum, Probing and Sample Operation
Follow the procedures in Chapter 4 of the EMPX-HF manual for information about vacuum operation, manipulating
the probe arm stages, sample exchange and imaging/probing the sample.
Temperature Operation
The cooling engine in the CRX-EM-HF is a two stage closed cycle refrigerator (CCR). The sample stage and probe
holders are thermally connected to the CCR 2nd stage through vibration isolation: the radiation shield stage and
probe arms are thermally connected to the CCR 1st stage through similar vibration isolation. The CRX-EM-HF is
capable of operating the sample stage to 400 K; however, to operate above 350 K, the probe holder thermal
anchors must be removed from the sample stage in order to avoid raising the probe temperatures to above their
350 K maximum temperature.
The recommended operation for variable temperature measurements is to allow the entire CRX-EM-HF station to
cool to base temperature and then to warm the sample stage to the desired measurement setpoint.
Controls for Temperature Operation
The CCR compressor and cold head in the CRX-EM-HF are identical to those used in the CRX-4K probe station.
Refer to section 4.5.1 of the CRX-4K manual for information about CCR and electronic controls in the CRX-EM-HF.
Cooling the Probe Station to Base Temperature
For station cooldown, follow the procedure in section 4.5.2 of the CRX-4K manual to cool the probe station.
Operating the Sample Stage from Base Temperature to 350 K
To operate the CRX-EM-HF from base temperature to 350 K, follow the procedure in section 4.5.3 of the CRX-4K
manual; however, use the sample stage controller settings given in Table 7 of this document to set P, I, and D and
the proper heater range settings for the temperature setpoint.
Operating the Sample Stage from 350 K to 400 K
To operate the CRX-EM-HF from 350 K to 400 K, use Chapter 4 of the EMPX-HF manual as a guide to remove the
probe holder thermal anchors from the sample stage. The thermal anchors can be left loose in the probe station or
tied to the probe arm using simple string or unwaxed dental floss. Follow the procedure in section 4.5.3 of the
CRX-4K manual; however, use the sample stage controller settings given in Table 7 of this document to set P, I, and

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D and the proper heater range settings for the temperature setpoint. It is necessary to operate the CCR second
stage heater output to a setpoint of 240 K to overcome the cooling power of the CCR.
CAUTION: The sample stage cannot be operated at temperatures >350 K indefinitely with the probe
mount thermal anchors connected to the sample stage because the probes may exceed their
maximum temperature of 350 K. For extended operation at maximum temperatures, the
probe mount thermal anchors should be removed from the sample stage.
NOTE: As a safety precaution, the Model 336 temperature controller included with the CRX-EM-HF
has been configured at Lake Shore with temperature limits set for each sensor input to
disable the sample stage heater if any of the limits are exceeded.
Returning to Room Temperature
To return the probe station to room temperature, follow the procedure in section 4.5.4 of the CRX-4K manual.
Temperature Control Summary
The temperature controller configuration tables (Table 4 and Table 5) and the CCR and electronic control settings
tables (Table 6 and Table 7) summarize the typical settings needed to maintain CRX-EM-HF temperature control.
Temperature
controller
Input
Sensor type*
Filter
Temperature
limit**
Input
units
Sensor curve
Sample stage
Top
Model 336
Input A
Cernox™ HT
On
(8 pts 10%
window)
420 K
Kelvin
User curve 21
Radiation shield
Input B
Silicon diode
360 K
DT-670
Probe arm
Input C
Silicon diode
360 K
DT-670
CCR second stage
Bottom
Model 336
Input A
Silicon diode
305 K
DT-670
CCR first stage
Input B
Silicon diode
305 K
DT-670
*Range for Si diodes is 2.5 V with diode current 10 µA. For platinum sensors, autorange and current reversal are on.
**Controller maximum temperature limit set above operational maximum to avoid nuisance system shutdown during operation.
Table 4: Model 336 input settings for the CRX-EM-HF
Temperature
controller
Output
Control input
Output
mode
Heater
resistance
Max
current
Power up
enable
Heater out
display
Setpoint
ramping
Heater
range
Top
Model 336
1
Input A
(sample stage)
Closed
loop PID
25 Ω
2 A
(for 100 W)
Off
Power
Off
Low-High
2
Input B (radiation
shield stage)
1.414 A
(for 50 W)
High
Bottom
Model 336
1
Input A
(CCR second stage)
2 A
(for 100 W)
2
Input B
(CCR first stage)
1.414 A
(for 50 W)
Table 5: Model 336 output settings for the CRX-EM-HF

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Probe
station
cooldown
Maintaining
sample stage at
base temp
Operating
sample stage
base to 350 K
Operating
sample stage
350K to 400 K
Returning probe
station to room
temperature
CCR control
settings
Main power
On
On
On
On
Off
Drive switch
On
On
On
On
Off
Cold head drive switch
Off
Off
Off
Off
Off
Remote drive switch
Off
Off
Off
Off
Off
Electronic
control
settings
Sample stage
Heater range
Off
Off
See Table 7
See Table 7
HIGH (100 W)
Nominal power
—
—
See Table 7
See Table 7
100%
Radiation shield stage
Heater range
Off
Off
Off
Off
HIGH (50 W)
Nominal power
—
—
—
—
100%
CCR second stage
Heater range
Off
Off
Off
See Table 7
HIGH (100 W)
Nominal power
—
—
—
See Table 7
100%
CCR first stage
Heater range
Off
Off
Off
Off
HIGH (50 W)
Nominal power
—
—
—
—
100%
Table 6: General CCR and electronic control settings
Sample Stage
Base to 20 K
20 K to 100 K
100 K to 250 K
250 K to 350 K
350 K to 400 K
Nominal Power
20% at 10 K
25% at 50 K
40% at 200 K
60% at 350 K
90% at 400 K
Heater Range
Medium
High
High
High
High
Proportional (P)
50
50
50
50
50
Integral (I)
20
20
20
20
20
Derivative (D)
0
0
0
0
0
CCR Second Stage
Nominal Power
Off
Off
Off
Off
90% at 400 K
Heater Range
-
-
-
-
High
Proportional (P)
-
-
-
-
50
Integral (I)
-
-
-
-
20
Derivative (D)
-
-
-
-
0
Table 7: Electronic control settings for the sample stage temperature operation