Printed Circuit Design & Fab - February 2009 - (Page 31)

MATERIAL rEGiStration ably ensure that the responsible engineer is further challenged by sorting through masses of machine, CAM and process data to try to identify the influence of material and process on scale factors and registration yield. Naturally, having the right tools for analysis and correction are essential. FiGurE 1 gives a representation of the non-precision methods. In any business cycle, but particularly in a negative economic climate, there should be two key criteria for any system: the system itself should provide rapid ROI and the system should maximize investment in existing capital and resource. Therefore, a good starting point is to have the system interface to equipment and systems that are currently available. By implementing an integrated system that can gather data from existing hardware and CAM systems, one can drive a step change in registration yield by using a powerful self learning model. The system provides accurate prediction of scale factor at CAM and essential reactive analysis to maximise yield of products in manufacturing. In taBlE 1, we look briefly at some of the manufacturing process from Pre-CAM through to drilling and identify where we can collect useful information that could drive an intelligent model. Recall that we are speaking of data that can drive a predictive model of PCB scale factors to be applied at CAM. Therefore, measurement needs to incorporate the layer-by-layer distortion during the lamination process and all prior processes. X Ray Drillers, X Ray CMMs or Intelligent Drill Systems (referred to as “optimizers” in the following text) are the only equipment in the above list that can provide scale data for every layer in the stack after lamination – the point when the sum Knowledge Makes the Difference A quick definition: Data are facts that are the result of observation or measurement. Information is meaningful data or data arranged or interpreted in a way to provide meaning. Knowledge is internalized or understood information that can be used to make decisions.1 In our industry, it is not a lack of data that limits making intelligent decisions about scale factor, on the contrary. With modern CAM systems and process hardware, PCB manufacturers could perhaps rightly complain that they have access to more data than they handle. Instead, what is required is a system that allows rapid, automated interpretation of complex data taken from key process step(s) in your facility and then converts this information into real-time reactive registration improvement – while providing the knowledge to drive accurate CAM prediction. Ideally, the system should use an automated visual approach to streamline data from multiple sources and display it in a uniform manner. taBlE 1. An intelligent approach to predictive registration improvement. process Data collection point (no ?) tool What information is the “data” giving us? Proprietary or in house systems for designing the material stackup ↓ cAM – scale factor prediction ↓ Artwork release Data collection* Video CMM to measure artworks before use Measurement and understanding of linear and non linear distortion of artwork prior to use. SPC data - artwork scale and alignment Identification and categorization of defects. Scale errors on every panel processed. SPC data available Scale errors on (optionally) every layer of every panel processed. SPC data available. Registration errors Plotter calibration, environmental, processor and film stabilization effects. Knowledge / Insight that is relevant to registration A “database” or file that contains the material attributes of the entire stackup PreCAM Stackup builder Inner layer imaging / UV expose AOI PEP and/or Automated lamination systems Post-lamination optimizer Data collection Data collection Data collection Data Collection UV exposure unit (or LDI) Modern systems provide excellent alignment and SPC scale data showing variation within and between production lots. Currently provides limited or no registration information - dependent on system A vital monitor of material and (prior) process variation – pre lamination. The critical point where one can first measure the cumulative scale errors locked in after lamination and verify layer to layer alignment An opportunity to compensate scale factor prior to drill to maximize yield. Limited long term benefit – purely reactive analysis. In some SBU systems measurement of inner layer targets by skiving may eliminate some post lamination optimization. Limited AOI system Integrated multi-camera measurement system X Ray Drill, Intelligent Drilling system Or X Ray Coordinate Measurement Machine X Ray inspection for 1st off drilled panels Laser Drill Visual only Visual X Ray system (e.g. Glenbook and similar) Skive target alignment available Drill Data Collection Neither Real time feedback of inner layer scale factor for layers 2 and n-1. limited Drilling Subsequent processes are not discussed in this article FEBRUARY 2009 printEd CirCuit dESign & fAB 31

Table of Contents Feed for the Digital Edition of Printed Circuit Design & Fab - February 2009

Printed Circuit Design & Fab - February 2009 Contents Our Line Market Watch Around the World Happenings ROI Tip Jar BGA Bulletin Interconnect Strategies Final Finsh Forum Defects Database Embedded Active Components In Multilayer LCP Packages Simulation: The Need for Speed Advanced Registration Systems The DC Design Squeeze Ad Index Do You Really Want a Better Autorouter? Designing With Conductive Materials, Part 1 Off th eShelf Marketplace On the Forefront

Printed Circuit Design & Fab - February 2009

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