by Abby Way

Created on: April 17, 2009

A motherboard is an essential computer part. Without it, you wouldn't be reading this - or anything on a computer, for that matter.

One of the first components needed is called a PCB, or printed circuit board. The inner layer is a sheer metal layer, and holes must be punched in it for all the parts. There can be 15,000 holes in a single motherboard! The PCB is then laminated in copper and checked. If it passes the check, it is routed to ensure the correct size, and the edges are smoothed and rounded. The boards are brushed, drilled, and deburred, and then the board is washed (the first of several washings it will undergo).

The PCB is copper-plated along with a number of other PCB's at the same time; a lot of chemicals are needed, and the machine needs to be cleaned between batches, so this saves money. In the process, they are first chemically cleaned and then chemicals are applied to plate the boards with copper. Another washing follows this process.

The boards are treated with more chemicals, and then they are photographed so that workers can inspect the surfaces more closely before etching the PCBs. Several workers carefully look over the photographs to make sure the board is in perfect condition.

Now, the circuits are etched into the PCB, before the board is washed again. It is soldered, then dyed to cover the traces beneath and protect them. The surface treatment comes next, and the holes on the PCB are treated with plating of nickel-gold. Important information about the boards is also printed on at this stage.

In the next stage, the smaller components are mounted. Automated machinery places components onto the boards and checks with sensors to make sure everything is in place properly.

The boards are checked manually with a precut template that should fit on the board and a scanning machine, and a worker feels the board for missing components. If it is missing anything, or a part is in the wrong place, it has that part manually soldered on or repositioned.

The larger parts such as serial ports and memory slots are positioned by hand next. After everything is put onto the board, it runs through a high-temperature machine that solders the parts on. It is then checked before it cools down, and if necessary, the soldering is completed manually.

A random selection of boards from a batch is connected to machines to test all the sockets, and if any are defective, the batch is screened.

A lesser number of randomly selected boards are subjected to more intensive tests, stress tests, and shipping tests to ensure the boards will work and survive shipping.

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