System and method for monitoring and improving dimensional stability and registration accuracy of multi-layer PCB manufacture

Abstract

Targets are inserted throughout the layout of a PCB. Post manufacture measurement of the targets are compared to pre-manufacture positions so as to calculate a non-linear regression analysis best-fit model. This model is used to predict a feature's location upon or within a PCB given the feature's position on the layout. The non-linear regression analysis results in a set of x and y polynomial equations. These polynomial equations allow for a linear compensation to be applied to the feature position on a layout so as to minimize misregistration of features in the manufacture of PCBs. Models of the features' post production positioning is made before and after linear compensations are made to the pre-manufacture positioning of the features Graphical presentations using wire frame diagrams and color coded diagrams help identify those areas of the panel that are projected to be in and out of tolerance relative to the specifications.

What is claimed is:  
     
         1 . A method for accurate positioning and registering features on a printed circuit board (PCB) panel comprising: 
 creating a layout having corners for positioning features on at least one base material panel;    positioning a plurality of targets on the layout;    recording the pre-manufacture nominal position of each target;    manufacturing at least one PCB from the at least one base material panel;    measuring the post manufacture actual position of each target;    recording the actual position of each target;    calculating a movement of the actual position of each target from the nominal position of each target;    modeling the movement of the plurality of targets during manufacture by analyzing the target movement to develop a regression analysis; and    applying the model to the pre-manufacture feature positions to compensate for the movement during the manufacture.    
     
     
         2 . The method of  claim 1  wherein the layout is in the form of artwork.  
     
     
         3 . The method of  claim 1  wherein recording the pre-manufacture nominal position of each target comprises: 
 establishing the pre-manufacture center of origin for all targets as a point within the layout;  
 assigning the nominal position of each target as horizontal and vertical coordinates relative to the center of origin; and  
 storing the nominal position of each target's horizontal and vertical coordinates for subsequent calculating post-manufacture movement.  
 
     
     
         4 . The method of claim.  3  wherein the step of calculating the post-manufacture actual position movement of each target comprises: 
 measuring the actual post-manufacture position of each target as horizontal and vertical coordinates relative to the pre-manufacture center of origin; and  
 computing each target's horizontal coordinate movement as the difference between the target's actual horizontal coordinate and the target's nominal horizontal coordinate; and  
 computing each target's vertical coordinate movement as the difference between the target's actual vertical coordinate and the target's nominal vertical coordinate.  
 
     
     
         5 . A system for accurate positioning and registering features on a PCB panel comprising: 
 means for producing a layout having corners for positioning features on at least one base material panel;    means for positioning a plurality of targets on the layout, said targets being dispersed throughout the at least one base material panel; means for recording the pre-manufacture nominal position of each target;    means for manufacturing at least one PCB from the at least one base material panel;    means for measuring the post-manufacture actual position of each target;    means for recording the actual position of each target;    means for calculating the movement of the actual position of each target from the nominal position of each target;    means for modeling the movement of the plurality of targets introduced during manufacture by developing regression analysis using the nominal coordinates of each target on the layout as the basis for modeling each target's post manufacture coordinates on the one or more base material panels; and    means for optimizing the position of features by compensating features' locations in the layout so as to compensate for the movement introduced in manufacture of the at least one PCB.    
     
     
         6 . The system of  claim 5  wherein the layout is in the form of artwork.  
     
     
         7 . A printed circuit board (PCB) with accurate layer registration produced by the process of  claim 1.