Semiconductor

Common gas & pressure challenges in semiconductor vacuum tools

1. Ultra low flow accuracy under vacuum

ALD precursors and carrier gases often run sub sccm to low sccm. Maintaining setpoint with minimal drift—despite changing back pressure during pump/purge—is critical for cycle to cycle repeatability.

2. Fast pulsing and short settling times

ALD/PEALD steps demand rapid, repeatable valve actions and stable flow/pressure within milliseconds to avoid overshoot, parasitic reactions and non uniform monolayers.

3. Stable chamber and line pressure

Load locks, throttle valves and pump downs create transients. Without active control, back pressure swings cause flow errors and film thickness variation.

4. UHP cleanliness & compatibility

Processes require 316L stainless steel, metal diaphragm designs, VCR®/face seal fittings, low outgassing and particle generation, plus options for corrosive gases.

5. Recipe agility & multi gas flexibility

R&D and pilot lines switch often between N₂, Ar, O₂, H₂, NH₃ and reactive/specialty gases. Minimising recalibration downtime keeps tools productive.

6. Data capture & tool integration

Cleanrooms need high rate digital data, totalization and easy PLC/DAQ integration for traceability, process optimisation and recipe verification.

How Alicat devices solve vacuum gas flow and pressure control

Alicat mass flow controllers (MFC/MFM)

Alicat’s laminar differential pressure architecture with integrated P&T sensing delivers fast control response, broad turndown, and stable low flow control that suit vacuum semiconductor processes.

• Vacuum friendly, low pressure drop options: Alicat’s low ΔP variants help maintain accuracy where upstream pressure is limited, improving control in pumped chambers and load locks.
• Fast, repeatable pulsing: Suitable for ALD/PEALD timing with minimal overshoot, improving within wafer and wafer to wafer uniformity.
• Multi gas, multi range flexibility: On instrument gas libraries and adjustable ranges support rapid recipe changes without lengthy off site recalibration.
• High purity build options: 316L SS, metal seal configurations and VCR® connections support UHP requirements.
• Integration & data: Analog (0–5 V, 4–20 mA) and digital serial options (e.g., Modbus) plus onboard totalizers enable straightforward DAQ/PLC connectivity and audit trails.

Alicat pressure controllers (PC/PCS)

For direct chamber or line pressure control from deep vacuum through positive pressure, Alicat PCs stabilise setpoints during pump/purge transitions and coordinate with MFCs to decouple flow pressure interactions across recipes.

Why Drastar pressure regulators are ideal for semiconductor gas systems

Drastar high purity pressure regulators are engineered for UHP gas cabinets, tool hook ups and process lines:

• UHP materials & construction: 316L stainless steel bodies, metal diaphragms, electropolished internals, and VCR®/face seal compatibility to maintain cleanliness and minimise outgassing.
• Excellent stability & low droop: Tight outlet stability across changing flows helps keep MFC inlets and process lines steady—vital for ALD, CVD and etch steps.
• Single and two stage options: Use as source regulators (gas cabinets/cylinders) or line regulators near the tool to mitigate supply side fluctuations.
• Wide range coverage: From very low outlet pressures for sensitive vacuum applications to higher pressure needs on abatement or utility lines.

Alicat + Drastar system approach

Feed Drastar as the source/line regulator to deliver a clean, stable supply into Alicat MFCs/PCs. This reduces inlet variability, improves MFC accuracy, shortens settling time during pulses, and stabilises chamber back pressure—driving better uniformity and yield.

Typical semiconductor use cases we support in the UK

• ALD/PEALD: Sub sccm precursor pulsing with stable back pressure for conformal, uniform films in high aspect ratio features.
• CVD/PECVD/Graphene: Multi gas blending with controlled ramp/soak while holding chamber pressure constant.
• RIE/ICP Etch: Accurate reactive gas delivery, minimal overshoot and steady line pressure for tight CD control.
• UHP gas cabinets & hook ups: Drastar single/two stage pressure regulation feeding Alicat MFCs for consistent tool supply.
• Load locks & transfer modules: Active pressure control through pump downs to minimise particle risk and pressure shocks.

Why partner with Premier Control Technologies (UK)

• UK supply & support for Alicat mass flow and pressure control optimised for the vacuum industry.
• Drastar high purity regulators sized and configured for your UHP gas panels and tool hook ups.
• Cleanroom aware application engineering—materials compatibility, leak integrity and installation guidance.
• Hethel based coverage for fabs, OEMs and universities across the UK.

Tell us your process (ALD, CVD, etch) and target flow/pressure ranges. We’ll size an Alicat MFC/PC and Drastar regulator package that stabilises your vacuum process and scales from lab to pilot to fab. Contact us by email on sales@pctflow.com or call us on 01953 609930.