Method for fabricating a protection circuit located under fuse window

A method of fabricating a semiconductor device comprising:

• providing a semiconductor substrate;
• forming at least one fuse circuit in the semiconductor substrate, wherein the fuse circuit comprises:
• a fuse having a first end connected to a first voltage, and a second end;
• a first transistor having a first current electrode (drain) connected to a second voltage, a control electrode (gate) for receiving an input signal, and a second current electrode (source) connected to the second end of the fuse;
• a second transistor having a first current electrode connected to the second voltage, a control electrode, and a second current electrode connected to the second end of the fuse;
• a first diode having an anode and a cathode, the anode of the first diode connected to the first voltage and the cathode of the first diode connected to the second end of the fuse;
• a second diode having an anode and a cathode, the anode of the second diode connected to the second end of the fuse and the cathode of the second diode connected to the second voltage;
• a resistor having a first end connected to the second end of the fuse, and a second end;
• and
• an inverter having an input end connected to the second end of the transistor, and an output end connected to the control electrode of the second transistor for providing an output signal;
• and
• forming a fuse window overlying the at least one fuse circuit.

A method of fabricating a semiconductor device with a protected output signal, the method comprising:

• providing a semiconductor substrate;
• providing first and second voltage terminals on the substrate;
• connecting a first end of a fuse to the first voltage terminal;
• connecting an anode of a first diode to the second voltage and a cathode of the first diode connected to the second end of the fuse;
• connecting an anode of a second diode to the second end of the fuse and a cathode of the second diode to the first voltage;
• connecting a first end of a resistor to the anode of the second diode;
• and
• connecting an input of an inverter to a second end of the resistor, and connecting an output of the inverter to a circuit for providing the output signal.