CHAPTER 4 – Real World Guidelines for Commercial Fabrication Houses

This chapter discusses the real-world guidelines for commercial fabrication houses. The best thing one can do when releasing a board to a fabrication house is to send them the design files. They can extract all the information right from the design files and also check them for any errors. Circuit board fabrication houses routinely build boards with trace widths of 4 mils or less. It is found that the smaller the trace width gets, the lower the yield the fabrication house achieves and the more costly the boards are. Professional board houses can handle boards with all spacing 4 mils or less. It is suggested to make all pads for components as large as possible. This allows having more leeway in layer registration, thus increasing yields. In order to give an idea of what the design rules from a commercial fabrication house can look like, the chapter includes the design rules for two fabrication houses: Nexlogic Technologies and Capital Electronics. The guidelines are further differentiated into standard and high density processing (just to make matters more confusing). The effective difference between the “high density processing” and the “standard processing” to the consumer is strictly cost. If a board can be designed with the rules as described in the standard processing sections, the cost is lower as compared to the high density processing.