When bonding pads, the through hole diameter is usually larger than the actual size 12mil, and 40 mil: 80mil is usually larger than the actual size by 20mil.
Extended data:
When the operating system wants to schedule a process to execute, it should investigate its current status and priority from the PCB of the process; After being scheduled to a process, it is necessary to set a scene for the process to resume operation according to the processor state information stored in its PCB, and find its programs and data according to the memory start address of the programs and data in its PCB;
During the execution of a process, when it needs to synchronize, communicate or access files with the cooperating process, it also needs to access PCB;; When the process is suspended for some reason, the processor environment of the breakpoint must be saved in PCB.
It can be seen that in the whole life cycle of a process, the system always controls the process through PCB, that is, the system perceives the existence of the process according to the PCB of the process rather than anything else. So PCB is the only sign of the existence of the process.
Baidu encyclopedia -PCB