Huihe Circuit

Six-layer castellated FR-4 board

Thickness / finish

1.2 mm / ENIG

Outer trace / space

4 / 4 mil

Inner trace / space

4 / 3.5 mil

Hole notation

0.2 mm minimum; finished status unspecified

Release the edge outline, castellated hole positions, copper keepouts and mating-board solder land together. Huihe asks for the mechanical outline to pass through each half hole. Agree edge plating, burr inspection and the retained pad after routing.

The page's separate general half-hole guide gives a 500 µm minimum diameter and 900 µm pad. That is not substituted into this example's 0.2 mm hole field: identify which holes are edge castellations and which are internal vias.

Six-layer resin-filled pad construction

Material / finish

FR-4 / ENIG

Thickness

2.0 mm

Inner & outer trace / space

4 / 3.5 mil

Hole notation

0.25 mm minimum; not labelled finished

Specify which pads require resin filling, planarisation and copper capping. Agree acceptable depression, protrusion and void inspection beneath the assembly pads. The photograph alone cannot establish that these inspection conditions were met.

Huihe also shows a 0.8 mm six-layer electroplated-fill board and a 2.0 mm ten-layer electroplated-fill board. Its process table distinguishes IPC 4761 Type VII options from a special unclassified option. Ask which option applies; resin filling and copper filling are not interchangeable quotation lines.

Six-layer Rogers + FR-4 mixed stack

The accompanying specification says Rogers 4350 + FR-4, 2.3 mm thickness and ENIG, with 7/7 mil outer and 5/5 mil inner trace/space, and a 0.6 mm minimum-hole notation. It does not supply a controlled-impedance target, measured loss or a finished-hole tolerance.

Request the exact laminate grade suffix, dielectric thicknesses and bonding materials for each layer. Name the RF reference planes, design frequency, coupon method and accepted impedance or insertion-loss limits. This mixed stack is different from the second catalogue example, which specifies Rogers 3003 + FR-4 and 2.0 mm thickness.

Two-layer F4BM PTFE

This example specifies 0.8 mm thickness, 1/1 oz finished outer copper and lead-free HASL. The source gives Dk 2.35 and a 0.3 mm minimum-hole field, but does not attach a measurement frequency or method to that Dk figure.

Agree the full F4BM grade and supplier lot record, dimensional-control requirements and the finish suitable for the assembly. Ask for a material datasheet at the frequency used by your design rather than treating a bare Dk number as a performance guarantee.

Six-layer heavy copper

The adjacent specification gives FR-4, 1.8 mm thickness and ENIG, outer trace/space 4.5/2.5 mil and inner 4/3.5 mil. It states 6 oz copper but does not map that weight to every layer. The listed minimum hole is 0.6 mm, without a finished-hole definition.

Release a per-layer finished-copper schedule and ask where cross-sections will be measured. Confirm whether the fine outer spacing belongs to the heavy-copper conductor layers and how etch compensation, solder-mask coverage and solderability are controlled. The page's 12 oz sample/volume headline is a separate claim; it is not assigned to this 6 oz example.

Six-layer rigid-flex with one-step HDI

The catalogue gives 1.6 mm thickness and 4/4 mil trace/space, with 0.2 mm through-hole and 0.07 mm blind-hole notation. The latter is a specific example, smaller than the general rigid-flex table's 0.075 mm laser-hole field. Confirm the proposed drill and lamination route rather than assuming this exception is routine.

Supply the installed bend drawing, flexible-zone layer stack, bend radius and expected cycling. Agree coverlay, rigid-to-flex transition and coupon positions. The page identifies an automotive-radar application; it does not provide radar performance or bend-life results for the pictured board.