The patterns for the electrical circuits, solder mask, nomenclature, etc. are created with Computer-Aided Design (CAD) tools and transmitted from our customers via direct data communications links. The artwork is translated from the digital data onto photo tools. The digital data is also used to create computer programs that control drilling and testing of the PC board.

A number of panels, “pinned and stacked” together, can be drilled at the same time. Stack height may range from 1 to 4 panels.

Holes are drilled in the panel using a computer-controlled program generated from CAD output. The plated-through holes are used to provide paths for making electrical connections between PC board's various layers. Some of these holes are also used as receptacles for mounting connector pins or other components on the PC board. Non plated-through holes are used as attachment holes for mounting connectors to the PC board or attaching the board to the equipment in which it will be installed.

After drilling, each panel is passed through a machine, known as the hole inspector, which counts the number of holes in the panel. The panels are also passed through a de-burr machine (mechanical brush) to remove any burrs.

Electroless copper plating is a chemical immersion process which provides conductivity between all copper interfaces.

The outer-layer print process is a very similar process to that used in the creation of inner-layer lines. First, the panel surface is cleaned and photo resist is applied.

The photo-tool used in the outer layer print exposure process is opposite to that used for inner layers. In this case, the circuit pattern is dark on the photo-tool.

When the panel is developed, the circuitry pattern in the resist develops away.

Electrolytic Copper plating serves to build up the copper plating thickness both in the holes and on the traces.

After the copper is plated, tin is plated over the surface of the copper. This protects the copper lines from etching when the resist is stripped off and the unwanted copper is etched away.

The resist is then stripped off.

Next the exposed copper (not protected by tin) is etched away leaving the desired circuitry pattern. The tin is then stripped off to leave exposed copper circuitry.

Liquid Photo-Imageable Solder Mask is used to protect the circuits and provides electrical insulation. L.P.I.S.M. is coated onto the boards with one of the following processes: curtain coat, electrostatic spray, or screen coat.

L.P.I.S.M. hardens when exposed to UV light. During exposure, a photo-tool is placed over the panel. The dark areas of the photo-tool prevent exposure of the L.P.I.S.M. on the copper pads.

After exposure, the panel is developed to wash away the unexposed solder mask. The mask is then cured.

Legend is used to indicate the position of components on the circuit board. It is printed on the boards via a silk-screening process.

HASL stands for Hot Air Solder Level. This solder protects the copper circuits from corrosion/oxidation, and provides a solderable surface for the customer's assembly process. The HASL is placed on the panel by immersing in a molten solder and then blowing hot air over the panel.

The rout process is a milling process in which a rout bit is used to cut the profile of the desired board contour. The panels are “pinned and stacked” as previously done during the “Drill” process. The usual stack is 1 to 4 panels.

The purpose of electrical test is to check the electrical integrity of the circuit, i.e.: to make sure the circuits are complete and carry the correct currents. Using a test fixture, which consists of a series of pins, every circuit is tested. The pins are aligned with the features. Current is passed between one test point and a test point on the same track. If a signal is detected the circuit is okay. Every circuit is tested on the panel.

A final inspection checks for visual defects and those that would not necessarily fail the Electrical Test.

As a final check to ensure the product meets our customer's standards, and prior to pack and ship, a quality audit is performed on board lots.

Product is packed according to customer specifications and shipped.