Baratron Etch Manometer For Deposit-Prone Etch Applications

MKS Instruments, Inc. has introduced the new Baratron Etch Manometer for deposit-forming plasma etch applications, such as advanced metal etch. The Baratron Etch Manometer contributes to productivity improvement by: eliminating measurement uncertainties due to process-induced zero drift caused by particulate contamination and deposits on the measuring diaphragm; by minimizing production time lost while the manometer is re-zeroed after process drift; and by dramatically extending instrument lifetime. In addition, units are temperature-controlled at 45° or 100°C to minimize deposition of condensable gases.

Plasma etch processes can produce by-products that deposit a film on all exposed surfaces in the vacuum chamber, including the diaphragm of the manometer. Film deposits on the diaphragm can cause the manometer pressure reading to drift, requiring re-zeroing. Although temperature control of the sensor helps reduce deposits, new gas chemistries and tighter process parameters can still lead to deposits on the diaphragm.

The new Baratron Etch Manometer minimizes process drift by significantly reducing deposits on the diaphragm. A unique deposition baffle (patent pending) is structured into the sensor housing. This structure creates a flow channel between the baffle and the sensor housing, causing gas flow to be redirected through the flow channel before it reaches the diaphragm. This protects the diaphragm from deposits while allowing the gas molecules to reach the diaphragm for accurate pressure measurement.

Another cause of process-related drift is particulate contamination. As the demands on deposition and etch processes increase, reaction rates are accelerated, causing an increase in generated by-products in the form of particles that deposit on instrument surfaces. This can cause the manometer zero reading to drift. In the Baratron Etch Manometer, a patented Contaminant Exclusion System (CES) has two-stages that prevent particles from contaminating the diaphragm without affecting the pressure measurement

The Etch Manometer is accurate to ±0.25% of Reading and is available in Full Scale ranges down to 50 mTorr.

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