MFC metal shim etching is a photo-chemical subtractive process used to manufacture the precision metal plates, laminar flow elements, and critical orifice shims inside a Mass Flow Controller (MFC). These thin stainless steel or alloy parts define the laminar flow path and calibrated orifice that govern gas delivery accuracy in semiconductor, vacuum, and process gas systems. Unlike laser drilling, which creates recast, burrs, and heat-affected zones, chemical etching produces clean, burr-free holes with controlled geometry across large shim arrays. The process supports stainless steel, nickel, and Hastelloy across thicknesses from 0.02 mm to 0.30 mm, with hole tolerance in the single-digit micrometer range.

Parameter Window

• Available Materials: 304/316 stainless steel, nickel, Hastelloy

• Material Thickness Range: 0.02–0.30 mm

• Hole Tolerance: ±1–5 µm

• Minimum Hole Diameter: ≈ 1.0–1.2 × material thickness

• Edge Quality: Burr-free, controlled side etch, clean aperture

• Compliance: SEMI / high-purity gas compatible

Manufacturing Process / Workflow (8 Steps)

1. DFM & Artwork Review — Translate flow channel and orifice layout into compensation artwork, accounting for side etch and flow calibration.

2. Material Pre-treatment — Degrease, acid-clean, and dry the metal sheet for uniform resist adhesion.

3. Dry Film Lamination — Laminate photosensitive dry film on both sides under controlled conditions.

4. UV Exposure & Development — Expose through phototool or LDI, then develop to reveal the hole and channel pattern.

5. Controlled Chemical Etching (Core Step) — Spray etchant on both sides until through-etch completes, forming precision holes and channels.

6. Resist Stripping & Cleaning — Strip dry film, multi-stage rinse, and clean to remove all etchant residue.

7. Post-treatment — Electropolishing, passivation, or cleaning per high-purity gas requirements.

8. Inspection & Calibration Readiness — Micro-hole, dimensional, and cleanliness inspection; packaged for clean assembly.

Core Advantages

1. Burr-Free, Clean Micro Holes — Chemical etching avoids laser recast, dross, and heat-affected zones, keeping flow passages clean.

2. Tight, Repeatable Hole Geometry — Aperture diameter and spacing hold at micron scale for consistent laminar flow.

3. No Mechanical or Thermal Damage — No burr, no work-hardening, no micro-cracks from drilling or punching.

4. Complex Channel Arrays — Etching can form dense, custom flow channels and multi-hole patterns in one thin shim.

5. High-Purity Material Compatibility — Stainless and Hastelloy shims clean easily and resist process gas corrosion.

6. Fast Iteration — Artwork-based tooling lets engineers tune flow calibration quickly without hard tooling.

Typical Applications

• Mass Flow Controllers (MFC) — Laminar flow elements and calibrated orifice shims.

• Gas Delivery Systems — Restrictor plates in semiconductor gas panels.

• Vacuum and Leak Detection — Precision capillary and restrictor elements.

• Analytical Instruments — Flow splitter and restrictor shims for gas analyzers.

• Semiconductor Process Tools — High-purity gas distribution plates.

• Medical and Laboratory Gas — Precision flow control shims.

Design Notes & Process Considerations

1. Compensate artwork for side etch so final hole diameter matches the flow calibration target.

2. Balance shim thickness against hole diameter—too thin risks deformation, too thick increases side etch.

3. Specify electropolishing or passivation for high-purity, corrosive gas service.

4. Control etchant concentration, temperature, and spray pressure for consistent hole-to-hole geometry.

5. Validate cleanliness and particle content per gas panel assembly standards.

6. Group related flow geometries into one artwork for fast tuning iterations.