PCB manufacturing
Future Trends in PCB Production
What key trends will shape the future of PCB production? John Cunningham, Chief Chemist, Rainbow Technology Systems Ltd has identified some key drivers that are universal to the electronic sector and looks to answer this broad, yet complex question.
W
hen Rainbow Technology embarked on a journey six years
ago to develop a new method of PCB production, the following factors were taken into account: All manufacturers want to cut costs without compromising quality.
All manufacturers want to improve yields and reduce wastage and reject rates.
There is an overriding pressure to make processes greener. This not only means the use of more environmentally friendly materials but also making every effort possible to reduce energy consumption in the manufacturing process.
Features are becoming increasingly smaller therefore there is a greater demand for fine line circuitry than ever before.
The result was the Rainbow Processing Unit – an automated PCB production unit incorporating coating, imaging and developing in one compact enclosure.
Traditional PCB production The process for producing PCBs has changed little in the past 50 years. There have been incremental improvements in quality and efficiency but nothing revolutionary. At present PCB manufacturing equipment requires a substantial capital investment as it must be housed in a clean room environment and the machinery takes up considerable amounts of space. The process starts with either laminating the copper boards with dry film protected with Mylar™ or roller coating with a solvent-based coating which is then passed through a hot air or infrared oven to remove the solvent and leave a dry film. Due to long drying times, often in a horizontal position, debris can get on to the panel which can lead to occlusions later in the imaging process These dry film or coated panels are then transported under yellow light to the imaging unit.
Imaging is carried out with an off-contact process using collimated light, which at present can only achieve imagining down to 50 microns. The imaged panel is then transported (again in yellow light) to the developing station where the 20-25 microns of film or coating spend 1-2 minutes being developed before storage or forwarding to
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www.siliconsemiconductor.net Issue IV 2012
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