Photochemical etching is a precision subtractive manufacturing process that uses photoresist masking and controlled chemical dissolution to pattern thin metal sheets. Compared with stamping, laser cutting, CNC machining and water jet cutting, photochemical etching offers unique advantages that make it the preferred process for thin, complex metal components. The advantages of photochemical etching become most apparent when parts require burr-free edges, ultra-fine features, low prototyping cost and consistent batch quality. Across semiconductor packaging, medical devices, electronics, new energy and aerospace industries, photochemical etching has become the go-to process for precision thin metal parts that conventional methods struggle to produce economically.

Process Overview

• Core principle: Chemical dissolution at room temperature, no mechanical force, no heat
• Material range: Stainless steel, copper, phosphor bronze, Kovar, nickel, titanium, nitinol, molybdenum
• Thickness range: 0.01 mm ~ 1.5 mm
• Minimum feature: 0.02 mm micro holes and slots
• Tolerance: ±0.005 mm ~ ±0.05 mm depending on thickness
• Production format: Single sheet, panelized batch, reel-to-reel continuous roll

Manufacturing Process

1. DFM & artwork review: Side undercut compensation, material and tolerance evaluation
2. Surface pre-treatment: Degreasing, pickling, cleaning for photoresist adhesion
3. Dry film lamination: Photoresist applied to both sides under cleanroom conditions
4. UV exposure & development: CAD pattern transferred via UV, unexposed resist removed
5. Controlled chemical etching: Spray etchant dissolves exposed metal; through-etch or half-etch available
6. Resist stripping & cleaning: Resist removed, parts rinsed and dried
7. Quality inspection: Dimensional, edge and flatness measurement
8. Optional post-processing: Plating, passivation, electropolishing, forming as required

Core Advantages of Photochemical Etching

1. Burr-free, stress-free edges: Unlike stamping or laser cutting, photochemical etching uses chemical dissolution at room temperature. There are no burrs, no residual stress, no work hardening and no heat-affected zone. Parts come out smooth and ready for immediate use without secondary deburring.
2. Ultra-fine micro feature capability: Photochemical etching reliably produces 0.02 mm micro holes, fine pitch arrays and intricate contours. Stamping is limited by die clearance; laser cutting by beam spot size. Etching can achieve features that no other conventional process can economically produce on thin metal foil.
3. Low tooling cost and fast prototyping: Design changes only require updated digital phototool, no expensive hard stamping dies. Prototype parts are delivered in 1–3 days, cutting R&D cycle time dramatically. This makes photochemical etching ideal for product development and frequent design iteration.
4. Consistent batch quality: Automated production lines with in-line process control ensure uniform dimensions from the first prototype to mass production. Every part on the panel has identical feature size, edge quality and thickness, meeting strict industry quality requirements.
5. Wide material compatibility: Photochemical etching works with most thin engineering metals — stainless steel, copper, phosphor bronze, Kovar, nickel, titanium, nitinol, molybdenum. It preserves each material's original properties including conductivity, spring temper, shape memory and corrosion resistance.
6. Design flexibility and panel nesting: Multiple parts of varying shapes and sizes can be nested on one panel. Half-etch fold lines, partial thinning and custom contours are all achievable in a single process step, reducing assembly complexity and material waste.

Typical Applications

• Semiconductor packaging: Lead frames, BGA/CSP stencils, shadow masks, packaging carrier plates
• Medical devices: Surgical meshes, implant components, sensor diaphragms, precision filters
• Electronics: EMI shielding cans, contact springs, connector terminals, battery contacts
• New energy: Fuel cell bipolar plates, current collectors, heat spreaders
• Optical instruments: Aperture plates, precision slits, encoder discs, grating sheets
• Aerospace & industrial: Precision shims, spacers, encoder components, lightweight structural details

Design Notes & Process Considerations

1. Minimum feature width should be at least 1.2–1.5× material thickness for stable etching results.
2. Side undercut must be compensated in artwork design to guarantee final dimensional accuracy.
3. Thinner foil supports finer features and tighter tolerance; thicker sheets have wider tolerance limits.
4. Half-etch depth should not exceed 50% of total thickness to avoid warpage.
5. Post-processing such as plating or passivation will slightly alter dimensions; reserve tolerance margin in design.
6. For ultra-thin foils, careful handling and fixture support are required throughout processing to prevent distortion.