Effects of scanning and biasing circuit restructuring on the response of a large area magnetic field sensor array

A large area magnetic field sensor array (LAMSA) has been designed and fabricated with built-in redundancy to achieve higher yield. The laser-link technology is used as the restructuring tool. The sensor system response is measured and calibrated with a general regression analysis method. Using the same method, an algorithm to evaluate the effects of the restructuring schemes of the biasing and scanning circuits on the response is developed. From measurements taken before and after restructuring, the influence of the row and the column scanning circuits restructuring are found to be weak, provided the resistance values of the formed laser-links are low, especially in the case of the column scanning circuit. Restructuring of the cascode current mirror acting as active load has shown the close dependence of the sensor cell responses on the transistor parameters. Helped by these restructuring schemes, the initial yield of 23 tested chips of size 6×3 mm was raised from 39 to 61%