Description

Application Scenarios

In a typical semiconductor CVD (Chemical Vapor Deposition) chamber, process pressure must be held within ±0.1 Torr across a 1–10 Torr setpoint to ensure uniform film thickness and repeatable wafer yield. Traditional Pirani or thermocouple gauges fail here because their readings vary with the type and mixture of process gas. The 626A01TBE solves this critical pain point—its capacitance manometer principle measures true absolute pressure via diaphragm deflection, completely independent of gas type, molecular weight, or thermal conductivity. When integrated with a chamber pressure controller and an MKS PDR-series power supply, the 626A01TBE becomes the trusted pressure reference that enables closed-loop throttle valve control, ensuring process repeatability shift after shift even as gas chemistry changes between recipes.

Parameter

Main Parameters	Value/Description
Product Model	626A01TBE
Manufacturer	MKS Instruments (USA)
Product Category	Capacitance Manometer / Absolute Pressure Transducer (Baratron® Series 626A)
Pressure Range	0–10 Torr (≈ 0–1333 Pa) Absolute — “01” code = 10 Torr full scale, suitable for rough-to-medium vacuum
Accuracy	±0.12 % of Reading (typical, includes linearity, hysteresis & repeatability at 23±5°C)
Output Signal	0–10 VDC linear with pressure; optional RS-485/Modbus on digital-configured variants
Power Supply	±15 VDC (analog version) or +24 VDC (digital/powered variant); requires MKS PDR or compatible supply
Diaphragm / Wetted Parts	Hastelloy C-276 diaphragm; 316L stainless steel sensor body & process port — resistant to common clean process gases
Process Connection	1/4″ VCR® female or ConFlat (CF) mini-flange (typically CF-1.33″ / DN16) — metal-seal ready for UHV
Sensor Heat / Temp Control	Internally heated & temperature-controlled (~45 °C) to prevent condensation & minimize ambient thermal drift
Response Time	< 20 ms (to 90 % of final value) — fast enough for real-time chamber pressure loop control
Operating Environment	Electronics: 0–50 °C; Process side up to 100 °C; Storage: –40 to +70 °C; 5–95 % RH non-condensing
Repeatability	±0.02 % of Reading — ensures day-to-day measurement consistency across recipe runs
Long-Term Zero Stability	Drift < 0.2 % FS / year under normal operating conditions with periodic zero calibration

Technical Principles and Innovative Values

Gas-independent capacitance manometry: The 626A01TBE uses a tensioned metal diaphragm (Hastelloy C-276) that forms one plate of a capacitor. Applied pressure causes nanometer-scale deflection, changing the capacitance against fixed electrodes. This physical measurement is fundamentally independent of gas type—unlike thermal conductivity gauges, the 626A01TBE gives identical readings for N₂, Ar, O₂, or mixed process gases with no correction factors required.
Active heated-diaphragm stabilization: An internal temperature-control circuit maintains the sensing cavity at ~45 °C, well above most process gas dew points. This prevents condensable vapor from depositing on the diaphragm (a leading cause of drift in unheated sensors) and eliminates errors from ambient temperature fluctuation, giving the 626A01TBE superior zero stability in 24/7 process environments.
High-linearity analog & optional digital output: The onboard signal-conditioning ASIC linearizes the capacitance-to-voltage conversion and outputs a low-noise 0–10 VDC signal proportional to absolute pressure. The “TBE” configuration supports industry-standard D-sub or circular connector pinouts for straightforward interfacing to PLC analog input modules, chart recorders, or MKS display/controllers.
Corrosion-resistant all-metal wetted path: With Hastelloy C-276 diaphragm and electropolished 316L SS process ports, the 626A01TBE withstands exposure to clean corrosive gases (Cl₂, SF₆, NF₃ in dry state) and is fully bakeable with the process side, extending service life in aggressive etch and CVD applications versus polymer-sealed sensors.
Fast response for closed-loop control: A < 20 ms rise time enables the 626A01TBE to be used inside pressure-control loops with motorized butterfly or pendulum throttle valves, allowing chamber pressure to be tightly regulated during pump-down, process steady-state, and pump-back phases.

Application Cases and Industry Value

In a 300 mm wafer fab plasma etch bay, six parallel etcher chambers were experiencing ±8 % variation in oxide etch rate traced to inconsistent chamber pressure readings from aging thermocouple gauges. After retrofitting each chamber with a 626A01TBE connected to the existing MKS PDR-4 power/display unit and re-tuning the throttle-valve PID loop, the measured pressure scatter dropped to ±0.3 %, and post-etch CD (critical dimension) uniformity improved by 12 %. Operators reported that zero-drift checks during weekly preventive maintenance showed < 0.5 % shift after six months of continuous operation—far better than the previously used hot-cathode or Pirani alternatives. The 626A01TBE directly contributed to reduced scrap rate and extended mean time between chamber cleans.In a university thin-film sputtering lab, the 626A01TBE was installed on a custom load-lock and main chamber to replace a mixed-gauge setup (Pirani + ion gauge). Researchers valued the single-gauge coverage from atmosphere down to ~1 mTorr with a linear, gas-independent readout—eliminating the confusing gauge crossover region and allowing one pressure setpoint to be used for both argon and reactive oxygen/nitrogen sputtering recipes. The lab reported faster pump-down qualification and simpler recipe documentation after adopting the 626A01TBE.