Stacked Modules and Method

Abstract

The present invention stacks integrated circuits into modules that conserve board surface area. In a precursor assembly devised as a component for a stacked circuit module in accordance with a preferred embodiment of the present invention, one or more stiffeners are disposed at least partially between a flex circuit and an integrated circuit. In a two-high stacked circuit module devised in accordance with a preferred embodiment of the present invention, an integrated circuit is stacked above a precursor assembly. The two integrated circuits are connected with the flex circuit of the precursor assembly. The present invention may be employed to advantage in numerous configurations and combinations of integrated circuits in modules.

1 . An assembly devised as a component for a stacked circuit module comprising: 
 a first CSP having upper and lower major surfaces, first and second lateral sides, and first CSP contacts disposed along the lower major surface;    a flex circuit configured for external electrical connection of the first CSP, the flex circuit comprising 
 lower flex contacts connected to selected ones of the first CSP contacts, and  
 first and second upper portions terminated by first and second edges, respectively, the first upper portion of the flex circuit being disposed above the upper major surface of the first CSP along the first lateral side, the second upper portion of the flex circuit being disposed above the upper major surface of the first CSP along the second lateral side, and the first and second edges being disposed a preselected distance apart above the first CSP;  
   a stiffener attached to the lower major surface of the first CSP.    
   
   
       2 . The assembly of  claim 1  in which the first CSP contacts at least partially project below the lower major surface of the first CSP.  
   
   
       3 . The assembly of  claim 1  in which the stiffener disposes the lower flex contacts apart from the lower major surface of the first CSP.  
   
   
       4 . The assembly of  claim 3  in which the flex circuit has plural conductive layers.