Metal can impedance control structure

A microelectronic assembly comprising:

• an interconnection element having a plurality of first element contacts and second element contacts thereon;
• a first microelectronic device having a rear face adjacent the interconnection element, a front face remote therefrom, and device contacts exposed at the front face, the microelectronic device having a plurality of edges;
• a plurality of first conductive elements extending from at least some of the device contacts of the first microelectronic device beyond at least one edge of the first microelectronic device to at least some of the element contacts, the plurality of first conductive elements extending beyond at least one of the edges of the first metal layer;
• a first metal can mounted to the interconnection element with the first microelectronic device and the first conductive elements therebetween, the first metal can having a surface disposed at a substantially uniform spacing from at least substantial portions of the first conductive elements, the conductive elements spaced a smaller distance from the metal layer than the distance of the conductive elements from the front surface of the first microelectronic device;
• a second microelectronic device having a surface and device contacts exposed at the surface, the second microelectronic device overlying the first metal can;
• a plurality of second conductive elements extending from at least some of the device contacts of the second microelectronic device beyond at least one edge of the second microelectronic device to at least some of the second element contacts, the second element contacts disposed beyond at least one edge of the first metal can, the second metal can having a surface disposed at a substantially uniform spacing from at least substantial portions of the second conductive elements,
• wherein the second metal layer is connectable to a source of reference potential, such that a desired impedance is achieved for the first and second conductive elements.

A method of manufacturing a microelectronic assembly comprising:

• providing a first microelectronic assembly including an interconnection element, a first microelectronic device mounted thereto, having a plurality of conductive elements extending between device contacts thereof and at least some first element contacts of the interconnection element;
• forming additional structure including a first metal layer overlying the first microelectronic assembly, the first metal layer having a surface disposed at a substantially uniform spacing from at least substantial portions of the first conductive elements, a second microelectronic device overlying the first metal layer, the second microelectronic device having a surface and device contacts exposed at the surface, second conductive elements extending between the device contacts of the second microelectronic device and at least some second element contacts of the interconnection element, and
• mounting a second metal layer above the second microelectronic device, the second metal layer having a surface disposed at a substantially uniform spacing from at least substantial portions of the second conductive elements, such that a desired impedance is achieved for the first and second conductive elements,
• wherein at least some of the first conductive elements extend beyond at least one edge of the first metal layer to the first element contacts.

A microelectronic assembly comprising:

• an interconnection element having a face and a plurality of element contacts and reference contacts exposed at the face;
• a microelectronic device having a rear surface overlying the face of the interconnection element and a front surface having first and second device contacts exposed at the front surface;
• a plurality of first conductive elements connecting first device contacts with the element contacts, the conductive elements having first lengths, and at least substantial portions of the first lengths extending a first height above the surface of the microelectronic device;
• a plurality of second conductive elements connecting the second device contacts with the reference contacts, the second conductive elements having second lengths, and at least substantial portions of the second lengths extending a second height above the surface of the microelectronic device, the second height greater than the first height, the first height being greater than the difference between the first and second heights, such that a desired impedance is achieved for the first conductive elements;
• and
• a conductive plane attached at least a substantially uniform distance above the at least substantial portions of the first lengths of the first conductive elements, the conductive plane being electrically connected to the second conductive elements and being connectable to a source of reference potential, the conductive plane extending at least substantially parallel to a plane in which the first conductive elements run.

A microelectronic assembly comprising:

• an interconnection element having a plurality of element contacts and reference contacts;
• a microelectronic device having a rear surface mounted to the interconnection element and a front surface having first and second device contacts exposed at the front surface;
• a plurality of first conductive elements connecting first device contacts with the element contacts, the conductive elements having runs extending above the surface of the microelectronic device, the first conductive elements being insulatively sheathed;
• a plurality of second conductive elements connecting second device contacts with the reference contacts, the second conductive elements having runs adjacent the runs of the first conductive elements;
• and
• a conductive plane disposed at least a substantially uniform distance above at least substantial portions of the lengths of the first conductive elements and being connectable to a source of reference potential, the conductive plane extending at least substantially parallel to a plane in which the first conductive elements run;
• and
• a conductive adhesive electrically connecting the conductive plane with the second conductive elements, such that a desired impedance is achieved for the first conductive elements.