Cubic Memory, Inc.

Vertical Circuits, Inc.

Vertical Circuits (assignment for the Benefit of Creditors), LLC

Alfons Vindasius

Kenneth M Sautter

Marc E Robinson

Larry Jacobsen

Donald Almen

William R Scharrenberg

The present invention provides an apparatus for vertically interconnecting semiconductor die, integrated circuit die, or multiple die segments. Metal rerouting interconnects which extend to one or more sides of the die or segment can be optionally added to the die or multi die segment to provide edge bonding pads upon the surface of the die for external electrical connection points. After the metal rerouting interconnect has been added to the die on the wafer, the wafer is optionally thinned and each die or multiple die segment is singulated from the wafer by cutting or other appropriate singulation method. After the die or multiple die segments are singulated or cut from the wafer, insulation is applied to all surfaces of the die or multiple die segments, openings are made in the insulation above the desired electrical connection pads, and the die or multiple die segments are placed on top of one another to form a stack. Vertically adjacent segments in the stack are electrically interconnected by attaching a short flexible bond wire or bond ribbon to the exposed electrical connection pad at the peripheral edges of the die which protrudes horizontally from the die and applying electrically conductive polymer, or epoxy, filaments or lines to one or more sides of the stack.

Assembly having stacked die mounted on substrate

Die assembly having electrical interconnect

A flip chip on chip assembly including a first flip chip; a second flip chip directly connected to the top of the first flip chip; and electrically conductive epoxy means disposed between the second flip chip and the top of the first flip chip to form an electrical connection between the first flip chip and the second flip chip. In another preferred embodiment, the present invention provides a flip chip assembly including a plurality of semiconductor chips where the plurality of chips are vertically interconnected on top of one another to form an electrically interconnected stack of chips; a flip chip directly connected to the top chip of the stack of chips; and electrically conductive epoxy means disposed between said flip chip and said top chip to form an electrical connection between the flip chip and the top chip. In still another preferred embodiment, the present invention provides a flip chip assembly including a semiconductor wafer having a plurality of first flip-chips formed thereon; a plurality of second flip chips, each one of the second flip chips directly connected to a respective one of the plurality of first flip-chips; and electrically conductive epoxy means disposed between the respective first flip-chip and second flip-chip connections to form an electrical connection between the respective first flip-chip and second flip chip connections. The present invention provides several very desirable features, including the ability to: (1) bond one die to another die in a flip chip fashion; (2) the ability to add a third die on top of the two flip chip die arrangement and wire bond that combination of three dies with two sets of wire bonds; and (3) the ability to further enhance the improved flip chip arrangement by combining a flip chip process (DCP) with a vertical integration process (VIP) to allow for the stacking of a plurality of die (e.g., N die). The flip chip on chip process according to the present invention provides for higher die density in the same board area and a reduction in the number of wires bonds that are required (therefore enhancing the reliability).

Conductive epoxy flip-chip on chip

An apparatus for vertically interconnecting stacks of silicon segments. Each segment includes a plurality of adjacent die on a semiconductor wafer. The plurality of die on a segment are interconnected on the segment using one or more layers of metal interconnects which extend to all four sides of the segment to provide edge bonding pads for external electrical connection points. After the die are interconnected, each segment is cut from the backside of the wafer using a bevel cut to provide four inwardly sloping edge walls on each of the segments. After the segments are cut from the wafer, the segments are placed on top of one another to form a stack. Vertically adjacent segments in the stack are electrically interconnected by applying electrically conductive epoxy to one or more sides of the stack. The inwardly sloping edge walls of each of the segments in the stack provide a recess which allows the electrically conductive epoxy to access the edge bonding pads and lateral circuits on each of the segments once the segments are stacked. A dielectric coating is applied to the die to provide a conformal coating to protect and insulate the die and a laser is used to ablate the area over the bond pads to remove the dielectric coating in order to provide for electrical connections to the bond pads.

Vertical interconnect process for silicon segments with dielectric isolation

A method for vertically interconnecting stacks of silicon segments. Each segment includes a plurality of adjacent die on a semiconductor wafer. The plurality of die on a segment are interconnected on the segment using one or more layers of metal interconnects which extend to all four sides of the segment to provide edge bonding pads for external electrical connection points. After the die are interconnected, each segment is cut from the backside of the wafer using a bevel cut to provide four inwardly sloping edge walls on each of the segments. After the segments are cut from the wafer, the segments are placed on top of one another to form a stack. Vertically adjacent segments in the stack are electrically interconnected by applying electrically conductive epoxy to one or more sides of the stack. The inwardly sloping edge walls of each of the segments in the stack provide a recess which allows the electrically conductive epoxy to access the edge bonding pads and lateral circuits on each of the segments once the segments are stacked. A thermally conductive epoxy preform is provided between the stack of segments so that the stack of segments are epoxied together. In one embodiment, the thermally conductive epoxy preform includes a plurality of glass spheres randomly distributed within the preform to maintain a distance between the stack of segments.

Method for forming vertical interconnect process for silicon segments with thermally conductive epoxy preform

An apparatus for vertically interconnecting stacks of silicon segments. Each segment includes a plurality of adjacent die on a semiconductor wafer. The plurality of die on a segment are interconnected on the segment using one or more layers of metal interconnects which extend to all four sides of the segment to provide edge bonding pads for external electrical connection points. After the die are interconnected, each segment is cut from the backside of the wafer using a bevel cut to provide four inwardly sloping edge walls on each of the segments. After the segments are cut from the wafer, the segments are placed on top of one another to form a stack. Vertically adjacent segments in the stack are electrically interconnected by applying electrically conductive epoxy to one or more sides of the stack. The inwardly sloping edge walls of each of the segments in the stack provide a recess which allows the electrically conductive epoxy to access the edge bonding pads and lateral circuits on each of the segments once the segments are stacked. A thermally conductive epoxy preform is provided between the stack of segments so that the stack of segments are epoxied together. In one embodiment, the thermally conductive epoxy preform includes a plurality of glass, spheres randomly distributed within the preform to maintain a distance between the stack of segments.

Vertical interconnect process for silicon segments with thermally

A flip chip on chip method for forming a flip chip assembly including a first flip chip; a second flip chip directly connected to the top of the first flip chip; and electrically conductive epoxy means disposed between the second flip chip and the top of the first flip chip to form an electrical connection between the first flip chip and the second flip chip. In another preferred embodiment, a method for forming a flip chip assembly including a plurality of semiconductor chips where the plurality of chips are vertically interconnected on top of one another to form an electrically interconnected stack of chips; a flip chip directly connected to the top chip of the stack of chips; and electrically conductive epoxy means disposed between said flip chip and said top chip to form an electrical connection between the flip chip and the top chip. In still another preferred embodiment, a method of forming a flip chip assembly including a semiconductor wafer having a plurality of first flip-chips formed thereon; a plurality of second flip chips, each one of the second flip chips directly connected to a respective one of the plurality of first flip-chips; and electrically conductive epoxy means disposed between the respective first flip-chip and second flip-chip connections to form an electrical connection between the respective first flip-chip and second flip chip connections.

Method for forming conductive epoxy flip-chip on chip

A method for vertically interconnecting stacks of silicon segments. Each segment includes a plurality of adjacent die on a semiconductor wafer. The plurality of die on a segment are interconnected on the segment using one or more layers of metal interconnects which extend to all four sides of the segment to provide edge bonding pads for external electrical connection points. After the die are interconnected, each segment is cut from the backside of the wafer using a bevel cut to provide four inwardly sloping edge walls on each of the segments. After the segments are cut from the wafer, the segments are placed on top of one another to form a stack. Vertically adjacent segments in the stack are electrically interconnected by applying electrically conductive epoxy to one or more sides of the stack. The inwardly sloping edge walls of each of the segments in the stack provide a recess which allows the electrically conductive epoxy to access the edge bonding pads and lateral circuits on each of the segments once the segments are stacked. A dielectric coating is applied to the die to provide a conformal coating to protect and insulate the die and a laser is used to ablate the area over the bond pads to remove the dielectric coating in order to provide for electrical connections to the bond pads.

Growing community of inventors

Saratoga, CA, United States of America

Alfons Vindasius