MATERIAL DESCRIPTION:
DiClad® laminates are woven berglass/PTFE composite materials for use as printed circuit board substrates. The woven
berglass reinforcement in DiClad products provides greater dimensional stability than nonwoven berglass reinforced PTFE
based laminates of similar dielectric constants.
These guidelines were developed to provide fabricators with basic information on processing double-sided and multi-layer
boards using copper clad DiClad series laminates. A Rogers’ technical service engineer or sales representative should be
contacted for more detailed processing information.
STORAGE:
DiClad series cores can be stored inde nitely at ambient conditions. A rst-in- rst-out (FIFO) inventory system is
recommended as a method of record keeping that would allow tracking of material lot numbers through PWB processing and
delivery of nished circuits.
Storage in Original Shipping Cartons
1) Stack cartons on a at surface that is safely out of the way of mobile handling and moving equipment. Cartons may be
stored on their side if nothing heavy is stacked on top.
2) Cartons should be stacked to a maximum of ve high to avoid excessive weight on the bottom packages.
Storage of Panels Removed from Cartons
1) For DiClad laminates with thick copper plates, the thick metal plate is not protected by anti-tarnish layers. As such, some
discoloration due to oxidation is expected during storage, especially under conditions of elevated temperature and
humidity. The oxidation can be removed by mechanical (deburr) or chemical exposure (microetch) which are standard to
the PCB fabrication process.
2) Panels thicker than 20 mils can be stored on edge in slotted shelving units keeping the clad surfaces vertical. This
provides easy access with low risk of damage to the metal surfaces.
3) If storage facilities do not permit vertical stacking:
A) The shelf must be at, smooth, and clean.
B) The shelf must extend beyond the full area of the panels being stored.
C) Surfaces of the laminates must be free of debris.
D) Shelf loading should be kept below 50 pounds per square foot.
E) Panels should be interleaved with soft, non-abrasive separator sheets.
DiClad® 870/880 Series High Frequency
Laminates
STRIPLINE AND MULTILAYER CIRCUITS
Technical ArticlesFabrication Notes
Advanced Connectivity Solutions
100 S. Roosevelt Avenue, Chandler, AZ 85226
Tel: 480-961-1382, Fax: 480-961-4533 www.rogerscorp.com
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Advanced Connectivity Solutions
100 S. Roosevelt Avenue, Chandler, AZ 85226
Tel: 480-961-1382, Fax: 480-961-4533 www.rogerscorp.com
Handling
PTFE-based materials are softer than most other rigid printed wiring board laminates and are more susceptible to handling
damage. Cores clad only with copper foils are easily creased. Materials bonded to thick aluminum, brass, or copper plates are
more prone to scratches, pits, and dents. Proper handling procedures should be followed.
1) Wear gloves of knit nylon or other non-absorbent material when handling panels. Normal skin oils
are slightly acidic and readily corrode copper surfaces. Fingerprints are di cult to remove as normal
brighteners will dissolve the corrosion, but leave corrosive oils in the copper to cause the ngerprint to reappear hours or
days later. The following procedure is recommended to remove ngerprints:
A) Bright dip in dilute hydrochloric acid.
B) Degrease in acetone, methyl ethyl ketone, or vapor degrease with chlorinated solvents.
C) Water rinse and bake dry for 60 minutes @ 250°F (125°C).
D) Repeat bright dip.
2) Keep work surfaces clean, dry, and completely free of debris.
3) Leave the polyethylene bag or sheet in place through initial processes such as shearing, sawing, blanking, and punching.
4) Only pick up panels by two edges. Thin cores in particular lack the sti ness required to support themselves by one edge
or corner, handling them in that manner may dimensionally distort the dielectric or impart a permanent crease.
5) During processing, cores should be transported between workstations on at carrying trays, preferably interleaved with a
soft, sulfur-free paper. Vertical racks should not be used unless they are slotted and
provide adequate vertical support.
INNER LAYER PREPARATION:
Tooling:
DiClad materials are compatible with many tooling systems. Choosing whether to use round or slotted pins, external or
internal pinning, standard or multiline tooling and pre vs. post-etch punching would depend upon the capabilities and
preferences of the circuit facility and the nal registration requirements. In general, slotted pins, a multiline tooling format,
and post-etch punching will meet most needs. Whichever approach is used, it is good practice to retain copper around
tooling holes.
A ow pattern compatible with the chosen adhesive system can be used between circuits and around the perimeter of the
panel. But, in general, registration of layers is improved by retaining as much copper as possible.
Surface Preparation for Photoresist Application:
A chemical process consisting of organic cleaners and a microetch is the preferred method of preparing copper surfaces for
coating with liquid or lm photoresist. A conveyorized spray system using an abrasive substance suspended in solution can
be used to prepare copper surfaces at the slight risk of some registration control. Mechanical scrubbing should be considered
for thick cores (0.060”+) only and, even then, should be performed at reduced pressures to minimize distorting the thin
laminate or imparting deep scratches that change the functional spacing between copper planes.
Photoresist Application:
Liquid or dry lm photoresist can be applied using traditional dip or spray coating, screening, or roll lamination processes.
DES Processing:
Developers, strippers, and copper etchants used to process epoxy glass materials will also work with DiClad layers. Thin