Weihong Peng

Deformation analysis of Multilayer Board in the lamination process

The deformation of core board affects the quality of circuit board, like misalignment, during lamination process of MLB (Multilayer Board). Three main factors causing the deformation are discussed, which are the mismatch of CTE (Coefficient of Thermal Expansion) among different materials, the residual stress in core boards and the special properties of the prepreg. Considering properties changing of the prepreg stage, the model of each stage in lamination process is developed. Then the deformation of core boards in a six-layer MLB is simulated using ANSYS software. Finally, the film compensating factor of 1.15 is determined according to the analysis results, and it is close to the actual factor applied in PCB manufacture process.

Research on dimensional change characteristics of silver halide films for multi-layer PCBs

The layer numbers and the density of circuit wiring increase day by day to meet the demand of the multifunction and miniaturization of electronic products during the manufacturing of printed circuit boards (PCBs). The dimensional stability of films determines the size and the alignment accuracy of images in each layer. This paper mainly discusses two aspects of silver halide films, the changing regularity of the film size after plotting and the influence of the exposure times on the film dimensional stability. It is indicated that silver halide films turn to be lengthening significantly in the first 9 hours after being plotted, and then trend to be stable. Film size contacts with the increase of exposure times during the exposure process.