Optimization of solder height for stencil printing process performance on length-width ratio

In this paper, various length-width ratio of printing pattern was designed on a ceramic substrate. The samples were prepared with SAC305 solder by stencil printing. The solder height was tested by coating thickness tester. It was found that squeegee load, squeegee speed, and separation speed were the main factors in the stencil printing process. The solder height was the highest when the squeegee load, squeegee speed, and separation speed were 40 N, 35 mm/s and 1.5 mm/s, respectively. According to the datasheet, a formula of quadratic equation was established. The deviation between experimental result and simulated data was below +/- 5%. Additionally, various length-width ratios also affected the solder height of stencil printing. When the length-width ratio exceeded 1.24, the solder height would decrease dramatically.