Packaging stacked chips with finger structure
View Patent ↗An improved finger structure applied to a packaging stack structure. The packaging stack structure is composed of several layers of chips, each chip is formed several leading wires and several finger sets are connected to the leading wire. Several finger units are formed on a finger set. The shape of these finger units is a strip structure with a bending angle, and the shape of these finger units is along an obverse direction of these leading wires to the finger unit and is changed corresponding to the obverse direction of the finger unit. The present invention can simplify the process and improve the reliability by changing the finger structure and continuously using the obverse bonding process to avoid the striking strength of the reverse bonding process.
1. A finger structure for a packaging stacked structure, wherein the packaging stacked structure includes at least a first and a second chips stacked one above another, and at least a first and a second leading wires, each coupled at one end thereof to a respective one of said first and second chips,
the finger structure comprising; at least one finger set connected to said first and second leading wires, said at least one finger set including at least one finger unit, formed as a flat strip-like structure entirely expanding in a single plane and having a first and a second co-planar bonding areas positioned on an obverse surface of said at least one finger unit, each of said first-and second leading wires being bonded at another end thereof to said first and second bonding areas, respectively, wherein said flat strip-like structure of said at least one finger unit is formed of at least two co-planar portions angled each to the other in the same plane at a predetermined bending angle.
2. The finger structure of claim 1 , wherein said at least one finger unit is V-shaped.
3. The finger structure of claim 1 , wherein said at least one finger unit is L-shaped.
4. The finger structure of claim 1 , wherein portions of said at least first and second leading wires on portions of said at least first and second chips are separately connected to the same finger unit of the same finger set.
5. The finger structure of claim 1 , wherein material of said at least first and second leading wires is selected from a group consisting of gold, aluminum and copper.
6. The finger structure of claim 1 , wherein the bending angle is arc-shaped.