A system such as a hard disk drive (HDD) may include one or more chips and/or other components (chips/components) that are attached to a printed circuit board (PCB). Each of the chips/components on the PCB may interface with one or more other chips/components. The chips on the PCB may also interface with other chips and/or other components that are located off of the PCB. In addition, the chips/components on the PCB may also communicate with a host.
The PCB is designed to provide interconnections between the chips/components. As the number of chips/components and interconnections therebetween increases, the complexity of interconnecting traces on the PCB also usually increases. In some PCBs, multiple interconnect layers are required. For example, four layers are commonly required.
After assembling the chips and/or other components on the PCB, a probe card may be used to test connectivity therebetween. Typically, vias are formed in the PCB to allow the probe card to perform testing from a back side of the PCB. However, the vias increase the cost of manufacturing the PCB. After testing connectivity, the system is booted and firmware testing is performed. The results of the firmware testing are analyzed. If the system passes the testing, the PCB can be assembled on a HDD with a relatively high reliability.
To reduce the cost of manufacturing the PCB, the size of the PCB, the number of vias, and/or the number of interconnect layers must be reduced. The cost cutting design changes must be accomplished without decreasing reliability or reducing functionality.