Description

<style>.e_editor{font:14px/24px Roboto,Helvetica,Tahoma,Arial,'Microsoft YaHei','b8bf53';}.e_editor div,e_editor p,e_editor td,e_editor th,e_editor li{font-weight:inherit;font-size:inherit;font-style:inherit;font-family:inherit;}.e_editor ul{margin:-10px 0 20px;}.e_editor li{padding:5px 0;}.e_table{width:96%;border-collapse:collapse;empty-cells:show;}.e_table th,.e_table td{padding:5px;border:2px solid #eee;}.e_img{padding:10px 0;text-align:center;}.e_p{line-height:20px;padding:0 0 20px;text-indent:0em;}</style> <div class="e_editor"> <div class="e_p"> I have a board with the above problem from our PCB supplier. After they applied the solder mask and run the PCB's to HASL process, the solder mask bubbled on one side of the PCB making the <a href="https://www.allpcb.com/soldermask/soldermask_thickness.html" target="_blank">solder mask thickness</a> higher and PCB looking awkward. </div> <div class="e_p"> They said they are pushing in solder mask inside the holes during my conversation with them...what is that "pushing in solder mask inside the via" process? is this common way of applying solder mask onto 12.0 to 25.0 mils via holes? </div> <div class="e_p"> What are the possible causes of the solder mask bubbling during HASL process? </div> </div>