The complexity of printed circuits boards increase at the same rate of functions that they have to perform．The physical dimensions of boards decrease more and more，that influences the density of connections，the number of tracks and components．Telecom and Information technology are the industry sectors that drive the research and displace the limit forward day by day．On HDI boards there ia the resort to a huge number of layer connections trough blind and buried vias．To maintain competitiveness it is mandatory to increase the dimensions of production panels in order to reduce the waste of materials and the impact of process costs．The drive to this direction iS a must to the reduction of limits that the unreliability of some process invoives．Unluckily there are some physical limits of base materials and those are a very heavy burden to overcome．The Durpose of the present document is to show the key factors that have to be considered to reach an high accuracy and precision for Successful laser drilling in SBU printed circuit boards．The BGA with 0．5 mm pitch iS widely used in many boards used in Telecom and IT．The designer demands more compact boards with tracks up to 50 pm and BGA 0，400 mm pitch．Those values can be reached and still produced with good traditional machines，without expensive and surely more 8gcurate LDI machines．More and more the Printed Circuit Boards axe unique products but produced in senes．More and more the demand of Iaser drilling iS massive and distributed on several sequential layers．A large panel is demanded in order to reduce costs impact of processes and waste of base materials．With big dimensions the danger of bad registration is enlarged and choosing huge panels corresponds to magnify poor accuracy.A good result iS the consequence of severaIlittle cares．Every process step has to be considered it lt gtves a contribution to the registration．
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