Wafer Metal Etched Template: Precision Packaging Mask

The wafer metal etched template is a precision metal mask used across wafer-level packaging and advanced packaging-and-testing processes. It is formed by photochemical etching: a thin metal foil is coated with photosensitive film, patterned by exposure and development, then dissolved selectively by etchant to create micron-level openings, shaped windows and dense arrays. Because chemical etching applies no mechanical force and no processing stress, thin templates resist deformation and support repeated use on wafer-level lines. The template governs solder-paste volume, flux distribution, plating coverage and coating accuracy, directly driving micro-joint consistency and packaging yield. Its aperture dimension, hole position, flatness and edge quality are the key control points for every wafer-level application.

Parameter Window

• Available Materials: stainless steel, nickel-based alloy, copper alloy

• Material Thickness Range: 0.03–0.3 mm

• Aperture Tolerance: ±3–5 µm

• Minimum Feature: 1.2–1.5 × material thickness

• Surface / Edge Quality: burr-free, smooth edges

• Compliance: semiconductor-grade cleanliness

Manufacturing Process / Workflow (8 Steps)

• Material Selection & Pre-treatment — Choose low-stress foil; degrease, pickle and activate the surface.

• Dry Film Lamination — Laminate photosensitive film on both faces under controlled temperature and pressure.

• UV Exposure / LDI — Transfer wafer pad arrays and openings to the photosensitive layer.

• Development — Wash away unexposed film to expose regions for etching.

• Controlled Chemical Etching (Core Step) — Double-sided spray etching; tune concentration, temperature and pressure to stabilize undercut.

• Resist Stripping & Cleaning — Remove the mask, multi-stage rinse and dry.

• Post-treatment — Passivation, polishing and precision cleaning per wafer-level cleanliness.

• Full Inspection — Verify aperture, position, flatness and edge burrs hole-by-hole.

Core Advantages

• Stress-free forming: No mechanical impact, thin templates stay flat.

• Micron-level patterns: Small apertures, shaped windows and dense arrays.

• Design flexibility: Pattern changes only require artwork revisions.

• Cost-effective: Mature process, low unit cost, short lead time.

• Wide material range: Stainless, nickel-based and copper alloys.

• Clean, burr-free edges: Reduces contamination in clean wafer processes.

Typical Applications

1. Wafer ball placement and solder-paste printing

2. WLP solder-paste stencils

3. RDL (redistribution layer) masks

4. UBM electroplating masks

5. Coating and developing masks

6. Selective plating and etching masks

Design Notes & Process Considerations

1. Apply hole-position compensation to offset undercut and printing deformation.

2. Keep minimum feature at 1.2–1.5 × foil thickness for reliable etching.

3. Match template thickness to solder-paste volume and pad geometry.

4. Optimize hole-wall verticality for ultra-fine-pitch ball placement.

5. Verify flatness to ensure uniform printing pressure across the wafer.

6. Enforce semiconductor-grade cleanliness to avoid particle defects.