Dimensional Adjustment
Dimensional compensation applied to the photolithography artwork or the laser drilling data accounts for the material movement that occurs during the lamination process. This panel scaling involves expanding or contracting the design dimensions so that the finished features align correctly after the resin cures and the board shrinks. The amount of scaling is determined by empirical testing and historical data for specific material types.
Registration Accuracy
Maintaining the vertical alignment of pads across twenty or more layers depends on the precision of the scaling factors used for each individual core. Because inner layers undergo different degrees of heat and pressure, they do not all shrink at the same rate. Incorrect panel scaling leads to misaligned vias and broken connections between layers.
Material Property
Fibres in the glass weave style determine the degree of dimensional change within the resin matrix. Manufacturers must calibrate their equipment for every new batch of laminate to ensure that the scaling factors remain accurate. This process involves measuring a set of test coupons before and after lamination to calculate the precise percentage of change in both the length and width directions, allowing for adjustments that prevent the accumulation of error in high-precision designs.
This data-driven approach is essential for achieving the tight tolerances required by modern electronic packaging.
