ULVAC Crystal Oscillation Deposition Controllers and Sensors

Overview

ULVAC CRTM series deposition controllers use the quartz crystal microbalance (QCM) method to provide real-time measurement of thin-film deposition rate and accumulated thickness. The CRTM-6000G and CRTM-9200 controllers accept sensor heads from the CRTS series, connected via OSC-12 oscillator and cable sets. Replacement crystals are available in gold and silver coated variants at 5 MHz and 4 MHz.

QCM Operating Principle

A quartz crystal oscillates at a fundamental resonant frequency determined by its cut, dimensions, and mass. During deposition, material accumulates on the crystal surface, increasing its mass and reducing the resonant frequency according to the Sauerbrey equation. The deposition controller measures the frequency shift and converts it to a thickness reading using the material density and acoustic impedance (Z-ratio). The rate is calculated from the rate of frequency change over time.

Crystal Resonance and Mass Sensitivity

Standard ULVAC crystals operate at 5 MHz (or 4 MHz for selected applications). The mass sensitivity of a 5 MHz AT-cut quartz crystal is approximately 17.7 ng cm⁻² Hz⁻¹. As deposited mass accumulates, the resonant frequency decreases. The crystal must be replaced when frequency shift becomes too large — typically when accumulated thickness exceeds a few thousand angstroms (material dependent), or when the frequency falls outside the oscillator lock range, or when the crystal fails to oscillate cleanly.

Tooling Factor

The tooling factor (TF) corrects for the geometric difference between the flux received at the sensor crystal and the flux received at the substrate. It is determined experimentally by depositing a known thickness on a test substrate while measuring the crystal reading, then adjusting TF until the controller reading matches the measured film thickness. TF values are chamber-specific and depend on source geometry, source-to-substrate distance, and sensor position. Record tooling factors for each source position after initial calibration.

Crystal Lifetime and Replacement

Crystal lifetime depends on the material deposited and its acoustic properties. Materials with high density or acoustic impedance mismatch reduce effective lifetime. In typical PVD applications a crystal may serve for several hundred angstroms of deposition before requiring replacement. Replace the crystal when: the oscillator loses lock; the rate display becomes unstable; or the accumulated thickness reading approaches the crystal limit shown in the controller. Always warm up the new crystal for several minutes before starting a deposition run.

Crystal Replacement Procedure

1. Vent the chamber or isolate the sensor if a gate valve is fitted
2. Allow the sensor head to cool if water cooling has been active
3. Remove the sensor head from the flange and place on a clean surface
4. Remove the retaining cap and lift out the exhausted crystal
5. Handle new crystal by its edges only — avoid touching the coated faces
6. Insert the new crystal, replace the retaining cap, and refit the sensor head
7. Allow the crystal to equilibrate to vacuum temperature for at least 5 minutes before use
8. Zero the controller and verify stable oscillation before beginning deposition

Cooling Water Requirements

CRTS-4 and CRTS-6 sensor heads require cooling water to protect the crystal from radiant heat from the source. Ensure cooling water flow is established before opening the source shutter. Recommended water temperature inlet: 15–25 °C. Do not allow cooling water to fall below dew point of ambient air to avoid condensation on the sensor body. Use clean, deionised water where possible to prevent scale in the cooling passage.

Oscillator Cable Length Limits

The OSC-12BG and OSC-12DG oscillator and cable sets are available in lengths from 4 m to 20 m. Longer cables introduce additional capacitance that can affect oscillation stability. These cable sets are not compatible with bakeable sensor configurations — verify cable type before installation. The outer cable length must match the oscillator cable length in each set.

Material Density and Z-Ratio

The controller requires density and acoustic Z-ratio (impedance ratio) values for each material to convert frequency shift to thickness accurately. The following are approximate reference values for common materials — verify against your specific process calibration:

• Aluminium (Al): density ~2.7 g cm⁻³, Z-ratio ~1.08
• Copper (Cu): density ~8.9 g cm⁻³, Z-ratio ~0.44
• Gold (Au): density ~19.3 g cm⁻³, Z-ratio ~0.38
• Silicon dioxide (SiO₂): density ~2.2 g cm⁻³, Z-ratio ~1.07
• Titanium (Ti): density ~4.5 g cm⁻³, Z-ratio ~0.62

These values are approximate guides only. Always verify using calibrated film thickness measurements for your specific deposition conditions.

CRTM Deposition Controllers

Part Number	Model	Specification	Weight (kg)	Origin
210006468100	CRTM-6000G	Without sensor, without outer cable	4.10	Japan
210006468200	CRTM-6000G 220V	Without sensor, without outer cable — 220 V	4.10	Japan
210006880900	CRTM-9200	Without outer cable — without additional option board	8.50	Japan
210006881000	CRTM-9200	Without outer cable — 1 option board inserted	8.50	Japan
210006881100	CRTM-9200	Without outer cable — 2 option boards inserted	8.50	Japan
210006881200	CRTM-9200	Without outer cable — 3 option boards inserted	8.50	Japan
210006881300	CRTM-9200	Without outer cable — 4 option boards inserted	8.50	Japan
210006881400	CRTM-9200	Without outer cable — 5 option boards inserted	8.50	Japan

CRTS-0 Sensor Heads (No Water Cooling)

Part Number	Model	Inner Cable Length	Connector	Frequency
210006888700	CRTS-0	0.2 m	OSM, UCR-5MAU-01 ×1	4 MHz / 5 MHz
210006888800	CRTS-0	0.5 m	OSM, UCR-5MAU-01 ×1	4 MHz / 5 MHz
210006888900	CRTS-0	0.9 m	OSM, UCR-5MAU-01 ×1	4 MHz / 5 MHz

CRTS-4 Sensor Heads (4 mm Cooling Water)

Part Number	Model	Flange / Terminal	Sensor Length	Inner Cable	Weight (kg)
210006889000	CRTS-4	Without flange	≤120 mm	0.2 m	0.30
210006889100	CRTS-4	Without flange	120–400 mm	0.5 m	0.30
210006889200	CRTS-4	Without flange	401–800 mm	0.9 m	0.40
210006889300	CRTS-4	Feedthrough terminal dia. 30 mm	≤120 mm	0.2 m	0.30
210006889400	CRTS-4	Feedthrough terminal dia. 30 mm	120–400 mm	0.5 m	0.40
210006889500	CRTS-4	Feedthrough terminal dia. 30 mm	401–800 mm	0.9 m	0.40
210006889600	CRTS-4	CF70 flange, feedthrough terminal dia. 30 mm	≤120 mm	0.2 m	0.40
210006889700	CRTS-4	CF70 flange	120–400 mm	0.5 m	0.40
210006889800	CRTS-4	CF70 flange	401–800 mm	0.9 m	0.50
210006890800	CRTS-4U	CF70 flange	100–800 mm	OSM connector	0.70

CRTS-6 Sensor Heads (6 mm Cooling Water)

Part Number	Model	Flange / Terminal	Sensor Length	Inner Cable	Weight (kg)
210006889900	CRTS-6	Without flange	≤120 mm	0.2 m	0.30
210006890000	CRTS-6	Without flange	120–400 mm	0.5 m	0.30
210006890100	CRTS-6	Without flange	401–800 mm	0.9 m	0.40
210006890200	CRTS-6	Feedthrough terminal dia. 30 mm	≤120 mm	0.2 m	0.30
210006890300	CRTS-6	Feedthrough terminal dia. 30 mm	120–400 mm	0.5 m	0.40
210006890400	CRTS-6	Feedthrough terminal dia. 30 mm	401–800 mm	0.9 m	0.40
210006890500	CRTS-6	CF70 flange, feedthrough terminal dia. 30 mm	≤120 mm	0.2 m	0.40
210006890600	CRTS-6	CF70 flange	120–400 mm	0.5 m	0.40
210006890700	CRTS-6	CF70 flange	401–800 mm	0.9 m	0.50
210006890900	CRTS-6U	CF70 flange	100–800 mm	OSM connector	0.80

Multi-Sensor Heads

Part Number	Model	Pins	Crystals Included	Inner Cable	Weight (kg)
210006898200	CRTS-M6 12P	12 pins	UCR-5MAU-01 ×6	0.9 m, OSM connector	0.90
210006898300	CRTS-12NS 12P	12 pins	UCR-5MAU-01 ×12	0.9 m, OSM connector	2.10
210006892000	CRTS-M6	—	UCR-5MAU-01 ×6	0.9 m, OSM connector	0.90
210006892100	CRTS-12NS	—	UCR-5MAU-01 ×12	0.9 m, OSM connector	2.10

Oscillator and Cable Sets

OSC-12BG sets include oscillator, auxiliary cable, and outer cable. OSC-12DG sets additionally include OSC control cable. Not compatible with bakeable sensor configurations.

Part Number	Model	Cable Length	Weight (kg)
210006891000	OSC-12BG 4 m	4 m	0.43
210006891100	OSC-12BG 8 m	8 m	0.63
210006891200	OSC-12BG 12 m	12 m	0.83
210006891300	OSC-12BG 16 m	16 m	0.93
210006891400	OSC-12BG 20 m	20 m	1.13
210006891500	OSC-12DG 4 m	4 m	0.43
210006891600	OSC-12DG 8 m	8 m	0.63
210006891700	OSC-12DG 12 m	12 m	0.83
210006891800	OSC-12DG 16 m	16 m	0.93
210006891900	OSC-12DG 20 m	20 m	1.13

Oscillators for CRTM

Part Number	Model	Specification	Weight (kg)
210006262100	OSC-12BG	RoHS compliance	0.20
210006262200	OSC-12DG	RoHS compliance	0.20

Replacement Crystals

Part Number	Model	Coating	Frequency	Pack Quantity	Weight (kg)
200009345400	UCR-5MAU-01	Gold	5 MHz	10 pcs/set	0.02
200009345500	UCR-5MAG-01	Silver	5 MHz	10 pcs/set	0.02
200009345300	UCR-4MAG-01	Silver	4 MHz	10 pcs/set	0.02
200000799200	CR5G1	Gold	5 MHz	5 pcs/set	0.01
200000799100	CR5S1	Silver	5 MHz	5 pcs/set	0.01