Abstract: A method for monitoring a fabrication of a circuit is disclosed. The method generally includes a step of (A) fabricating a chip only up to and including a first metal layer such that (i) a core region of the chip may has an array of cells, (ii) each of the cells may have a plurality of transistors and (iii) the chip may include a plurality of flip-flops. After the fabricating of step A has started, another step may be (B) designing a plurality of upper metal layers above the first metal layer. The upper metal layers (i) may interconnect a plurality of the cells to form the circuit, (ii) may form a plurality of scan chains from a number of the flip-flops not used in the circuit and (iii) may form a plurality of paths in the upper metal layers. Each of the paths generally connects a respective output of a first of the scan chains to a respective input of a second of the scan chains.

Abstract: A method for monitoring a fabrication of a circuit is disclosed. The method generally includes a step of (A) fabricating a chip only up to and including a first metal layer such that (i) a core region of the chip may has an array of cells, (ii) each of the cells may have a plurality of transistors and (iii) the chip may include a plurality of flip-flops. After the fabricating of step A has started, another step may be (B) designing a plurality of upper metal layers above the first metal layer. The upper metal layers (i) may interconnect a plurality of the cells to form the circuit, (ii) may form a plurality of scan chains from a number of the flip-flops not used in the circuit and (iii) may form a plurality of paths in the upper metal layers. Each of the paths generally connects a respective output of a first of the scan chains to a respective input of a second of the scan chains.

Abstract: An apparatus comprising a first control circuit, a second control circuit, a latch circuit and a flip-flop. The first control circuit may be configured to generate a first control signal in response to (i) an input signal from a fuse and (ii) one or more read signals. The latch circuit may be configured to change status in response to the first control signal. The second control circuit may be configured to change the state of the latch circuit in response to (i) one or more read signals and (ii) one or more set signals. The flip-flop may be configured to capture the state of the fuse in response to changing the state of the latch circuit with the first control circuit or the second control circuit.