Etching manufacturing process, commonly referred to as photochemical etching or chemical metal etching, is a non-mechanical subtractive precision metal fabrication method. It uses photoresist masking and controlled chemical dissolution to create custom patterns on thin metal sheets and foils. Unlike stamping, CNC machining or laser cutting, this process does not apply mechanical force or introduce thermal damage, making it ideal for thin, delicate, high-precision metal parts.

Process Workflow

1. Raw material preparation: Select metal sheet or foil (stainless steel, copper, brass, phosphor bronze, Kovar, nitinol, molybdenum etc). Ultrasonic degreasing removes oil, grease and surface contaminants to ensure photoresist adhesion.
2. Photoresist lamination: Dry film photoresist is hot-laminated on both sides of the cleaned metal substrate inside a clean environment.
3. UV exposure and development: Using a phototool mask, UV light transfers the required part geometry onto the photoresist. The unexposed photoresist is washed away during development, exposing the bare metal areas ready for etching.
4. Chemical etching: The patterned workpiece is conveyed through a spray etching machine. Ferric chloride etchant is sprayed onto exposed metal surfaces to selectively dissolve unprotected metal. Parameters including temperature, concentration, spray pressure and conveyor speed are tightly controlled for uniform etching. Partial half-etching is available for recessed features.
5. Stripping and cleaning: Remaining cured photoresist is stripped off. Workpieces go through neutralization and multi-stage DI water rinsing to eliminate residual etchant.
6. Post-treatment, inspection & metrology: Surface finishing, plating (Ni, Au, Ag) or passivation can be applied. Dimensional inspection, critical dimension measurement and visual defect check are performed before packaging and shipment.

Core Advantages

• Burr-free & stress-free parts: No mechanical cutting force, eliminating burrs and residual stress that may alter material properties. Original material characteristics such as elasticity, thermal expansion and conductivity are fully preserved.
• Complex patterns at low cost: Easily produce intricate outlines, dense hole arrays, narrow slots and half-etched structures. No expensive hard stamping molds. Design changes only require a new phototool.
• Wide material & thickness range: Works on most etchable metals, from ultra-thin foils starting at 0.01mm up to several millimeters thick sheets.
• High repeatability for mass production: Consistent dimensional accuracy across large batch runs, stable edge quality and uniform feature size.
• Fast turnaround for prototyping: Short lead time for samples, well suited for R&D verification, pre-production trials and low-to-high volume manufacturing.

Application Fields

• Semiconductor & electronic packaging: Lead frames, shielding cans, shadow masks, SMT stencils, Kovar hermetic components.
• Electronics & connectors: EMI/RFI shielding parts, phosphor bronze spring contacts, battery terminals, speaker grilles.
• New energy: Fuel cell bipolar plates, vapor chamber microchannels, precision filter meshes.
• Medical devices: Nitinol medical components, micro sieves, thin surgical parts.
• Aerospace & industrial instrumentation: Precision shims, spacers, encoder discs, metal nameplates.

Design & Process Considerations

• Feature size follows the standard rule: minimum opening width ≥ 1.2 × material thickness for reliable etching.
• Material selection affects etch rate; each metal alloy requires customized etchant formulation and process parameters.
• Half-etch depth must be clearly specified in CAD drawings, depth tolerance needs to be agreed at the design stage.
• Thin foils require careful handling and fixture design to avoid distortion during processing.
• Post surface treatments like plating, passivation or polishing should be considered early, as they may impact final dimensional tolerance.