Etched Lead Frames: First Frames and Fast Revisions, No Stamping Die

A package drawing lands on our desk. The silicon schedule is set, qualification has a date, and nobody has budgeted for a progressive die yet. That gap — between a finished drawing and a justified die — is where etched lead frames earn their keep.

Metching is a Dongguan etching plant working on electronics and semiconductor components since 2005. Lead frames are one of our core lines. We etch them in copper and stainless steel from 0.05 to 2.5 mm thick, straight off the package drawing, with no stamping die anywhere in the chain.

The working specs

Our standard copper alloy is H62 brass (UNS C27200). If your drawing names a different grade, we source to that grade per order — tell us at enquiry stage and we price it in.

• Thickness: 0.05–2.5 mm; most lead-frame work sits in the thinner half of that range

• Smallest features: leads, slots and tie-bar openings need to be at least roughly the material thickness — the working rule is ≈0.8–1.2× thickness

• Edges: burr-free on both faces, so nothing raised interferes with die attach, wire bonding or moulding

• Half-etching: downsets, tie bars and locking features can be half-etched in-house. Target depths and depth tolerances are evaluated against material thickness, drawings and processing requirements.

• Tolerance: Tolerances are evaluated based on material thickness, drawings and processing requirements. Metching does not apply a single fixed tolerance to every project.

• Plating: arranged through qualified partner finishers; the full range is available — nickel, tin, silver, gold and others on request

• Format: flat sheets only, up to 600 × 14,500 mm on stock 0.5 mm and thicker; thinner gauges run in smaller formats so they don't distort

Why development teams etch first

A stamped lead frame starts with a progressive die. Serious money, a long wait, and only then a first part. An etched frame starts with a drawing. On a new package, that difference decides whether qualification starts this quarter or next year.

Then the design moves. It always does — lead counts change, the paddle grows, tie-bar routing gets redrawn. Each move re-cuts a die, or it re-draws a film. Several etched iterations inside one development cycle isn't a compromise here; it's normal practice.

There's an assembly argument too. Stamping burrs drive mould-flash problems and can lift a lead under the wire bonder. Etched leads come off the sheet clean on both faces. Bonding-critical work defaults to etched frames for exactly that reason.

And in thin stock — 0.1 to 0.25 mm copper — dense lead patterns are everyday work. Every lead is defined photographically. No punch wears, nothing drifts over a run.

Where we stop recommending etching

Once a design freezes and volumes run into the millions, a progressive die usually wins on unit price. We say so up front. Etching's job is to prove the design and keep it supplied until the die pays for itself — plenty of customers etch with us first, then build the die to match the geometry the etched frames already validated.

Two hard boundaries: frame stock over 2.5 mm is outside our range, and we don't etch aluminium.

Questions we get

Etched or stamped — how do we choose?

Etch while the design is moving, for qualification and bridge builds, and at any volume where a die can't pay for itself. Stamp when it's frozen and the annual volume is genuinely large.

What limits the lead pitch?

The thickness rule. Gaps and leads need to be about the material thickness or wider, so thinner stock buys finer pitch. Send the package drawing and we check lead width, gap and tie-bar geometry feature by feature before quoting.

How fast are first frames?

Samples typically ship in 3–5 days; production runs 7–10. The point worth noting: samples and production run on the same digital tooling, so the frames you qualify on are the frames that ship — no process change hiding between the two.

Can you half-etch downsets and locking features?

Yes — half-etching is part of the etching process itself, done in-house. Flag the features on the drawing so we confirm depths (50–75% of thickness; deeper risks breaking through) before you plan around them.

CTA: Send the package drawing to info@metching.com or call +1 (630) 474-4019 — Metching, Dongguan · since 2005 · metching.com