Stacked-Die Bond Pad Layout With Exposed Pillar Wire Bonding
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Solution Overview
Problem
In 3D stacked-die packaging, reducing the size of the package while maintaining reliable electrical connections between dies is challenging due to the risk of bond wires touching the edges of the dies or the wire bonding apparatus failing to make good connections when bonding pads are too close to the edge.
Innovation Solution
The implementation of a pillar on the bonding pad of one die, allowing the first die to be mounted on top of the second die with the pillar exposed, enabling a wire to be bonded to both the pillar and the bonding pad, thereby reducing the minimum edge offset and package size without compromising the electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the offset between dies is reduced to decrease package size, then the package area is reduced, but the bond wires may touch the edges of the dies or reliable electrical connections cannot be made
Solution Approach 1:
The patent introduces a vertical pillar structure on the bonding pad of the second die, extending upward from the die surface. This adds a vertical dimension to the bonding interface, allowing the first die to be positioned closer horizontally while maintaining adequate clearance through the elevated bonding surface. The pillar creates a three-dimensional bonding geometry that resolves the two-dimensional conflict between package area and connection reliability
Solution Approach 2:
The pillar acts as an intermediary structure between the bonding pad and the bond wire connection point. It provides an elevated bonding surface that mediates the spatial conflict, allowing the bond wire to connect to the first die at a higher vertical level while maintaining horizontal clearance from the die edge. This intermediary structure enables reduced die offset without compromising connection reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the total horizontal area of the stacked die package by eliminating the need for excessive clearance, allowing for more compact packaging while ensuring reliable wire bonding connections.
Implementation Method 1
Wire bonding is typically performed using a wire bonding machine, which includes a capillary through which the bond wire is threaded, and which connects the bond wire to the bonding pads using pressure, heat, and/or ultrasonic energy.
Implementation Method 2
Wire bonding is typically performed using a wire bonding machine, which includes a capillary through which the bond wire is threaded, and which connects the bond wire to the bonding pads using pressure, heat, and/or ultrasonic energy.
Implementation Method 3
Wire bonding is typically performed using a wire bonding machine, which includes a capillary through which the bond wire is threaded, and which connects the bond wire to the bonding pads using pressure, heat, and/or ultrasonic energy.
Data Source
AI summary
Systems, methods, and devices for 3D packaging. In some embodiments, a semiconductor package includes a first die and a second die. The first die includes a first bonding pad on a top of the first die and near a first edge of the first die. The second die includes a second bonding pad on a top of the second die and near a second edge of the second die. A pillar is located on the second bonding pad. The first die is mounted on top of the second die such that the first edge is parallel to the second edge and offset from the second edge such that the pillar is exposed. A wire is bonded to a bonding surface of the pillar and bonded to a bonding surface of the first bonding pad.