Process Analyzer

Compact and Teflon Body Refractometer – PR23MS


A compact, teflon body refractometer for semiconductor liquid chemical processes. Connected to the process by a flare fitting, G1/2 inch female or a 1/2 inch NPT process connection. Mounted directly in-line without filtering.

  • Prevent wrong chemicals from entering the fabrication process.
  • Optimize etch process and increase the bath life of the etch solution (e.g. heated KOH).
  • Increase wafer throughput typically by +25%, and reduce cleaning chemical
    consumption (e.g. SC-1 or EKC-265) in FEOL and BEOL cleaning.
  • Achieve tight control of CMP slurries and better uniformity of the planarization process.
  • Bulk Chemical Supplies
    Changes in chemical quality can occur during in-house handling and storage. PR-23-MS activates 
    an alarm if the chemical is not within preset specifications and prevents wrong chemicals or wrong concentrations from entering the process.
  • Photoresist Development
    The photoresist developer concentration has a significant influence on the photoresist development step. An appropriate concentration of the developer should be maintained to comprise both the fabricating throughput and the pattern resolution. PR-23-MS can be used for real-time developer concentration monitoring instead of the traditional wafer-to-wafer or run-to-run methods.
  • Photoresist Stripping
    As stripping of most photoresists is an acid/base neutralization process, the speed and quality of photoresist stripping can be optimized by PR-23-MS when the strength of overall alkalinity is known.
  • Wet Etching
    As temperature and concentration of the etching solution have major impact on the wet etch rates, various etching processes can be optimized and etch end points determined when the chemical concentration is known. For instance, the KOH etch process can be optimized when the composition of heated KOH/H2O solution is continuously monitored with PR-23-MS.
  • Post Etch Wafer Cleaning
    PR-23-MS measures the concentration of expensive cleaning chemicals and polymer removals, such as EKC-265 in the post etch wafer cleaning. This provides a real-time indication of the bath and assists in increasing the bath lifetime and wafer pass in, and in reducing the chemical consumption.
  • Chemical Mechanical Planarization
    PR-23-MS provides a method for concentration monitoring of acids and chemicals, such as HF or HCl in the CMP abrasive slurries. This information can be used to determine the end point and to achieve a better uniformity of the planarization process.

Technical Details

Refractive Index Range (Standard)Full range, nD=1.3200…1.5300 (corresponds to 0…100% b.w.), spinel prism
Refractive Index Range
nD=1.2600…1.5000, sapphire prism (for Hydrofluoric acid, HF)
AccuracyR.I. ± 0.0002 (corresponds typically to ± 0.1% b.w.)
Repeatability and stabilitycorrespond to accuracy
Speed of Response1s undamped, damping time selectable up to 5 min
Patented CORE-opticsNo mechanical adjustments and
digital measurement with 3648 pixel CCD element,
589 wavelength sodium D-line light emitting diode (LED),
built-in Pt-1000 temperaturesensor
(linearization according to IEC 751)
Temperature CompensationAutomatic, digital compensation
Instrument VerificationWith standard R.I. liquids and
K-Patents documented procedure (ISO 9000)
Sensor PR-23-MSProcess connection with 1/2″ (F) Thread G; 1/2″
(F) NPT; 1/4″…1″ Pillar and Flare fitting
Sensor Wetted PartsTeflon® PTFE or Teflon® PFA or Kynar® PVDF or
AISI 316 L stainless steel as option,
prism gasket Teflon®, prism spinel (standard),
O-ring Kalrez, adaptor sapphire
Minimum Fluid Density (Float)=0.55 kg/l (SS/PTFE) , =0.85 kg/l (PVC)
Sensor Weight5.5 kg (12 lbs)
Process Temperature-20°C (-4°F)…150°C (300°F)
Ambient TemperatureSensor: min. -20°C (-4°F), max. 45°C (113°F)
Indicating Transmittermin. 0°C (32°F), max. 50°C (122 °F)
Sensor HousingAISI 316 L stainless steel, epoxy coated sensor cover
Sensor Protection ClassIP67, Nema 4
Approvals for Hazardous LocationsATEX approved for Zone II, area classification
EX II 3 G EEx nA II T4 / FM
approved for Class I, Div. 2,
Groups A, B, C & D / CSA certifi ed for Class I,
Div. 2, Groups A, B, C and D, T4
Approval for Electrical SafetycCSAus certified for Sensor: Class I, Poll. Deg. 3; Transmitter: Class I, Poll.
Deg. 2; Install. Cat. II.
PatentsUS Patents US6067151 and US6760098B2,
German Patent DE19855218
Indicating Transmitter DTR
Display320×240 pixel graphical LCD with LED backlight,
keypad with 8 membrane keys
Current OutputTwo independent current outputs, 4-20 mA, max. load 1000 Ohm,
galvanic isolation 1500 VDC or AC (peak),
hold function during prism wash
Ethernet Connection10/100 Mbit/s, data acquisition over UDP/IP Protocol with data acquisition software
PowerAC input 100-240 VAC/50-60 Hz, optional 24 VDC, 30 VA
Alarms / Wash RelaysTwo built-in signal relays, max. 250 V/3 A
Sensor ConnectivityOne or two sensors can be connected to one DTR.
Sensors independent with own
parameter sets and usable in different applications.
Two current outputs configurable
independently to indicate process concentration or
temperature of either sensor.
Remote FunctionsRemote display and access to real-time
measurement values, diagnostic messages,
altering configuration and parameter settings, and upgrading program versions ia Ethernet connection.
Indicating Transmitter Weight4.5 kg (10 lbs)
Transmitter Protection ClassEnclosure IP66, Nema 4X
Interconnecting CableIEC61158-2 compliant two-wire cable
Interconnecting Cable LengthStandard 10 m (33 ft), max. 200 m (660 ft)
OptionsCable fittings to Indicating transmitter: European cable glands M20x1.5

Note: Specification are subject to change without notice.