US Patent 7327040 Module substrate and disk apparatus

A module substrate includes an insulating substrate, a circuit pattern formed on at least a main surface of the insulating substrate, a protection film formed on the main surface of the insulating substrate including the circuit patter such as to expose a mount region of the circuit pattern, an active element part mounted on the mount region of the circuit pattern, a fluororesin film formed on the protection film at least in a vicinity of the mount region of the active element part, and an underfill filled between the active element part and the mount region of the circuit pattern.