Packaged multichip device with stacked die having a metal die attach

A leadless packaged multichip semiconductor device, comprising:

• a metal substrate having a through-hole aperture that has an outer ring configured for holding a bottom semiconductor die with a plurality of cuts through the metal substrate to define a spaced apart plurality of metal pads on at least two sides of the through-hole aperture including a row of inner metal pads and a row of outer metal pads;
• the bottom semiconductor die having a back side metal (BSM) layer on its bottom side and a top side with circuitry coupled to bond pads mounted top side up on the outer ring;
• a metal die attach layer directly between the BSM layer and walls of the metal substrate bounding the through-hole aperture to provide a die attachment that fills a bottom portion of the through hole aperture;
• bond wires between the inner metal pads and the bond pads,
• a dielectric adhesive on the top side of the bottom semiconductor die;
• a top semiconductor die having a top side with circuitry coupled to top bond pads mounted top side up on the dielectric adhesive over the bottom semiconductor die;
• pins connecting the top bond pads to the outer metal pads, and
• a mold compound including between adjacent ones of the metal pads.