Reproduceability Parameters in Thick Film

Abstract

<p> Thick-film resistors are being used in the hybrid microelectronics industry. One characteristic that has been considered for the thick film resistor i s the reproduceability in resistor value associated with the production techniques employed in the reproduceability in resistor value associated with the production techniques employed in the resistor manufactured. </p> <p> One parameter that has been associated with reproduceability is the yield figure; another parameter is the width of the resistance distribution for a given resistor production. These parameters can be used to identify the degree of reproduceability for the resistor production. A high yield figure or a small spread figure indicates a high degree of reproduceability. </p> <p> The effect of aspect ratio and sheet resistivity on the reproduceability has been evaluated for paste system A. Aspect ratios of 10, 5, 2 and 0.7 for a range of sheet resistivities (100, 1K, 10K, 100K, and 1M ohms per square) were investigated. Results show that for a given aspect ratio the amount of variation in spread for the range of sheet resistivities is negligible within the limits of error in the experiment. For a given sheet resistivity, the variation in spread for the range of aspect ratios is considerable. The spread of an aspect ratio of 10 is 25 ± 4%. For an aspect ratio of 0.7 the spread is 59± 7%. </p> <p> The effect of resistor location on spread for a 2" x 2" substrate has been studied. Results indicate that a higher degree of reproduceability can be associated with resistors located near the central (1" x 1") region of the substrate than the resistors located near the perimeter. </p> <p> The effect of increasing the resistor width on the reproduceability has been evaluated for resistors having aspect ratios near unity. Results show that as the resistor width is increased the spread in resistance decreases. For a width of 30 mil the spread in resistance is 37%. When the width is increased to 100 mil, the spread decreases to 21%. </p>