Adapter board for stacking Ball-Grid-Array (BGA) chips

A stacked Ball Grid Array (BGA) package comprising:

• a top BGA device having an array of first contacts on a lower surface;
• a bottom BGA device having an array of second contacts on a lower surface;
• an intermediate adapter card having a top surface facing the lower surface of the top BGA device, and a lower surface facing the bottom BGA device;
• a first array of metal contacts on the top surface of the intermediate adapter card for electrically contacting the array of first contacts of the top BGA device;
• intermediate metal traces on the intermediate adapter card that connect to the first array of metal contacts;
• peripheral connectors, electrically connected to the intermediate metal traces, disposed around edges of the intermediate adapter card;
• a bottom adapter card having a top surface facing the lower surface of the bottom BGA device, and a lower surface facing a mounting board;
• a second array of metal contacts on the top surface of the bottom adapter card for electrically contacting the array of second contacts of the bottom BGA device;
• peripheral pads on the top surface of the bottom adapter card, for contacting the peripheral connectors of the intermediate adapter card;
• bottom metal traces on the bottom adapter card that connect the second array of metal contacts to the peripheral pads;
• final bonding pads on the bottom adapter card and electrically connected to the bottom metal traces, for soldering to the mounting board, and
• a molding under the lower surface of the intermediate adapter card, the molding for shaping the peripheral connectors into a U shape.

A stacked-chip assembly for mounting on a mounting board comprising:

• upper arrayed package means, having a two-dimensional array of electrical connections with at least four rows and four columns, for connecting an enclosed integrated circuit through the two-dimensional array of electrical connections;
• lower arrayed package means, having a two-dimensional array of electrical connections with at least four rows and four columns, for connecting an enclosed integrated circuit through the two-dimensional array of electrical connections;
• intermediate adapter card means for interfacing to the upper arrayed package means;
• bottom adapter card means for interfacing between the lower arrayed package means and a circuit board;
• first metal contact means, on a first surface of the intermediate adapter card means, for matching a footprint of the two-dimensional array of electrical connections of the upper arrayed package means;
• lead frame means for wrapping around edges of the intermediate adapter card means from the first surface to below a second surface of the intermediate adapter card means;
• first metal means, on the first surface of the intermediate adapter card means, for electrically connecting the first metal contact means to the lead frame means;
• peripheral pad means, disposed around a periphery of a first surface of the bottom adapter card means, for making electrical contact with the lead frame means from the intermediate adapter card means;
• second metal contact means, on the first surface of the bottom adapter card means, for matching a footprint of the two-dimensional array of electrical connections of the lower arrayed package means;
• second metal means, on the first surface of the bottom adapter card means, for electrically connecting the second metal contact means to the peripheral pad means;
• and
• final bonding pad means, on a second surface of the bottom adapter card means, for making electrical contact with the circuit board,
• whereby the upper arrayed package means and the lower arrayed package means are stacked together using the intermediate adapter card means and the bottom adapter card means to route arrayed electrical connections to the periphery.