Ultra low loop development

This technical paper presents the ultra low loop height challenges faced in the development of miniaturized SOT-923 package. It is drawn from the package development experiences for Flat Lead packages of 0.8 mm × 0.6 mm × 0.4 mm (SOD-923) which was successfully developed and introduced commercially. This product is mainly used on hand-held applications where the size has become smaller. Therefore, loop height is needed to be controlled very low. In order to achieve such low loop height, several solutions have been considered: i) Bonding mode selection; ii) capillary selection for ultra low loop requirement; iii) development of special bonding parameters for ultra low loop control. iv) final product quality evaluation and reliability requirement which included wire pull test, ball shear test, wire peeling test and reliability test.