Multi-chip package module and a doped polysilicon trench for isolation and connection
A circuit module comprises a die attach pad with a surface and a plurality of leads surrounding the surface. A nonconductive adhesive is on the surface. A plurality of electronic circuit dies are on the surface of the die attach pad. Each die has a top surface and a bottom surface with the bottom surface on the adhesive. The top surface has a plurality of bonding pads. A first electronic circuit die has at least one routing path of a conductive material connecting a first bonding pad to a second bonding pad. A first bonding wire connects a bonding pad of a second electronic circuit die to the first bonding pad of the first electronic die. A second bonding wire connects the second bonding pad of the first electronic circuit die to a lead. Where one of the dies contains vertical circuit element, where a doped layer forms a terminal along the bottom surface of the layer, a trench filled with doped polysilicon extends from the top surface to the terminal to connect to the terminal. The doped polysilicon filled trench also serves to isolate and separate different circuit elements.
1. A circuit module comprising:
a die attach pad having a surface and a plurality of leads surrounding the surface;
a nonconductive adhesive on said surface;
a first electronic circuit die, having a top surface and a bottom surface with said bottom surface directly on said nonconductive adhesive, said top surface having a plurality of bonding pads, wherein the first electronic circuit die has at least one routing path of a conductive material connecting a first bonding pad to a second bonding pad, wherein said routing path is on said top surface of said first electronic circuit die;
a second electronic circuit die, having a top surface and a bottom surface with said bottom surface directly on said nonconductive adhesive, said top surface having a plurality of bonding pads;
a first bonding wire connecting a bonding pad of the second electronic circuit die to the first bonding pad of the first electronic circuit die;
a second bonding wire connecting the second bonding pad of the first electronic circuit die to a lead,
wherein said first electronic circuit die has an electronic circuit component having a first terminal in said first electronic circuit die on said bottom surface of said first electronic circuit die,
wherein said second electronic circuit die has an electronic circuit component having a second terminal in said second electronic circuit die on said bottom surface of said second electronic circuit die,
wherein each of said first or second electronic circuit die is made of a substantially single crystalline silicon and further comprises:
a trench filled with doped polysilicon with said trench extending from said top surface to said terminal,
wherein said doped polysilicon extends from said top surface to directly contact said terminal.
2. The module of claim 1 wherein said electronic circuit component is a vertical transistor with said terminal being a doped layer in said first and second electronic die near said bottom surface.
3. The module of claim 2 wherein said trench is formed by an etch process.
4. The module of claim 3 wherein said polysilicon in said trench is doped by diffusion.
5. The module of claim 2 wherein said doped layer is a buried layer.
6. The module of claim 2 wherein said doped layer is along the bottom surface.