Overview

Medical grade filter screen for semiconductor packaging photo chemical etching is a precision etching process that produces fine-aperture stainless steel filter meshes, grading screens and carrier filters from 316L and 304 sheet in one chemical step rather than by weaving, punching or laser drilling. Dry-film resist is laminated to both faces, the aperture array is exposed and developed through high-resolution film, and the unprotected metal is dissolved in a matched etchant, so thousands of uniform round, square or slot holes, rims and mounting tabs all form together with controlled open area. Because removal is chemical and burr-free, no loose burrs, recast dross or work-hardened edges remain to shed particles, which is the central requirement when a screen sits inside a clean semiconductor packaging line or a medical-grade fluid path.

For sourcing and process engineers, photochemical machining addresses three limits of conventional screening media on fine stainless meshes: woven wire cloth cannot hold a fixed aperture and sheds fibers at micron pitches, punched screens leave roll-over burrs and are limited by die strength at small holes, and laser drilling leaves heat tint, taper and recast particles that contaminate clean processes. Since the geometry lives in the film, a new pore size or open-area ratio is only a new artwork, and every aperture across a panel etches at the same rate, so hole diameter, pitch and open-area ratio stay consistent from the first article to volume cleanroom lots. Add tight control of particulate, ionic residue and bioburden through electropolishing, passivation, ultrasonic cleaning and clean vacuum packaging, and the approach fits packaging carriers, plating-bath filters and chemical delivery where cleanliness is as critical as aperture accuracy.

Parameter Window

• Available Materials: 316L, 304, 316 stainless steel, medical-grade low-carbon foil
• Material Thickness Range: 0.05–0.5 mm
• Tolerance: ±0.01 mm on aperture diameter, ±0.02 mm on pitch and rim profile
• Minimum Feature: 0.05 mm round hole with 0.06 mm web at 0.05 mm stock; open-area ratio 20–60%
• Surface Options: electropolishing, passivation, ultrasonic cleaning, cleanroom drying, vacuum packaging
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork Review — Convert 2D files to aperture arrays, verify hole diameter, web width and open-area ratio against stock thickness, and lock the rim and tab layout.
2. Material Prep — Select 316L or 304 by corrosion and cleanliness needs, shear low-carbon medical foil to panel size, and check for inclusions and surface defects.
3. Cleaning & Lamination — Degrease and rinse with deionized water, then hot-roll dry film onto both faces with pressure matched to film thickness so no bubbles sit under fine holes.
4. UV Exposure — Expose both sides through high-resolution film with front-to-back registration so apertures and mounting holes stay concentric.
5. Development — Wash away unexposed resist to open the metal to be removed, and inspect fine apertures under magnification for residual resist.
6. Etching — Spray chemistry matched to the stainless grade; time, temperature and conveyor speed govern the precision etching process, sidewall straightness and aperture diameter across the panel.
7. Stripping & Finishing — Remove resist and neutralize, then electropolish and passivate; run multi-stage ultrasonic cleaning and dry in a cleanroom to cut particle and ionic residue.
8. Inspection & Packaging — Verify aperture, pitch, open-area ratio and cleanliness against the approved sample, then vacuum-pack in a cleanroom with first-article measurements.

Core Advantages

1. Burr-free, low-particle edges: Chemical removal leaves no roll-over or dross, so screens shed no metal burrs into plating baths, encapsulants or clean gas lines.
2. Uniform aperture and open area: Every hole across a panel etches at the same rate, so pore size, pitch and open-area ratio stay consistent for predictable flow and retention.
3. No tooling for pore-size changes: A new aperture, pitch or open-area ratio is just a new film, keeping small cleanroom batches and custom meshes economical.
4. High open area with fine webs: Narrow ligaments and dense hole arrays are possible without die strength limits, balancing throughput with mechanical stiffness.
5. Cleanliness by design: Electropolished, passivated and ultrasonically cleaned surfaces plus vacuum packing hold particulate and ionic residue low for medical-grade duty.
6. Corrosion resistance intact: The 316L passive layer is preserved with no heat tint or work hardening, so screens tolerate aggressive chemistries and repeated sterilization.

Typical Applications

• Packaging carrier filter plates: Clean stainless meshes supporting dies and substrates during assembly and transfer.
• Plating-bath and electrolyte filters: Fine screens that trap particles in lead-frame and bump plating circulation.
• Encapsulant and underfill screens: Aperture plates filtering molding compound and underfill resin before dispensing.
• Wafer cleaning tank filter elements: Corrosion-resistant meshes in wet-bench chemical and rinse baths.
• Gas and chemical delivery filters: In-line screens protecting valves and mass-flow controllers from particulate.
• Medical-grade fluid filter modules: Biocompatible, low-residue components for diagnostic and dosing instruments.

Design Notes & Process Considerations

1. Hole diameter versus web: Keep the web at least comparable to stock thickness, or undercut will break narrow ligaments and collapse the open area.
2. Open-area ratio callout: State target open area and tolerance, since flow rate, pressure drop and retention cut-off all depend on it.
3. Cleanliness class: Specify particulate, ionic residue and packaging requirements for the cleanroom class, as these drive the finishing route more than the etch itself.
4. Aperture shape and taper: Choose round, square or slot holes and note allowable taper, because sidewall profile affects particle retention and backwash.
5. Grade and finishing: Prefer 316L for chlorides, acids and sterilants, and pair electropolishing with passivation to keep surfaces clean and passive.
6. Complete drawing data: State grade, thickness, hole shape, diameter, pitch, open area and cleanliness together; giving all seven items at once cuts back-and-forth confirmation.