A new semiconductor lithotripsy sensor

Calibration of lithotripters is important for proper therapeutic treatment of the patients suffering with the presence of the stones in the kidney. Hence, a new semiconductor lithotripsy sensor is developed here to study the optimum performance of the kidney stone disintegrators. The present lithotripsy sensor has four-arm Wheatstone bridge sensor chip having associated electronics of signal conditioning, and amplifier etc. on the chip itself, and is fabricated, by using conventional bipolar IC process, in combination with bulk micromachining process. The starting material used is 5 ohm-cm p-type (100) silicon. The chip size is 3 mm square and the size of anisotropically etched diaphragm is 1.0mm×1.5 mm×20 micron (thickness). The pressure sensitivity is found to be 10 V/mm Hg pressure, with nonlinearity of 0.20% full scale output and thermal stability less than +1.5% over a temperature range of -50° C to 300° C. The smart semiconductor lithotripsy sensor, due to better sensitivity and resolution, is found useful in monitoring of the acoustic intensity level and pressure amplitude (in MPa range) of the shock waves generated by the ESWL. The calibration of the lithotripters is discussed here in detail.