Semiconductor Package Overhang Deflection Control via Dummy Wires
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Solution Overview
Problem
In semiconductor package manufacturing, the deflection of the overhang portion during wire bonding leads to bonding failures and reduced manufacturing yield due to the pressing force of the capillary, which is not effectively offset by the dummy wires.
Innovation Solution
The method involves forming dummy wires that electrically couple dummy bonding pads and dummy bond fingers before forming conductive wires, which couple the bonding pads and bond fingers, thereby offsetting the capillary pressing force and suppressing deflection of the overhang portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the overhang portion is formed to extend beyond the structural body for wire bonding, then electrical connection between chip and substrate is achieved, but deflection occurs during wire bonding due to capillary pressing force
Solution Approach 1:
The patent applies preliminary anti-action by forming dummy wires before conductive wires to counteract the capillary pressing force. The dummy wires create a counteracting force that prevents deflection of the overhang portion during subsequent wire bonding operations, thereby maintaining stability while enabling reliable electrical connection.
Solution Approach 2:
The patent implements preliminary action by forming dummy wires in advance before the actual conductive wire bonding. This preliminary structure provides mechanical support and force balance during the wire bonding process, preventing deflection before it occurs and ensuring bonding reliability.
2Stability of the object's composition
If dummy wires are formed to offset capillary pressing force, then deflection is suppressed, but manufacturing process complexity increases
Solution Approach 1:
The dummy wires serve multiple functions: they provide mechanical support to prevent deflection, create counteracting force against capillary pressing, and maintain structural stability during bonding. This multi-functionality justifies the additional structural element by providing several benefits simultaneously.
Solution Approach 2:
The wire bonding structure is segmented into dummy wires and conductive wires with distinct functions. The dummy wires handle mechanical support and force balancing, while conductive wires handle electrical connection, allowing each component to be optimized for its specific purpose.
3Manufacturing precision
If the overhang portion is constrained to prevent deflection, then bonding accuracy improves, but manufacturing flexibility is reduced
Solution Approach 1:
The dummy wires act as an intermediary element between the overhang portion and the substrate. They provide the necessary mechanical support and force balance without directly constraining the overhang portion, allowing the conductive wires to perform electrical connection with high precision while maintaining design flexibility.
Data Source
AI summary
A method for manufacturing a semiconductor package includes disposing a structural body over one surface of a substrate formed with a plurality of bond fingers and a plurality of dummy bond fingers; forming an overhang portion by stacking a semiconductor chip formed with a plurality of bonding pads and a plurality of dummy bonding pads adjacent to one edge over the structural body such that the one edge projects out of a side surface of the structural body; forming a plurality of dummy wires which electrically couple the dummy bonding pads and the dummy bond fingers; and forming a plurality of conductive wires which electrically couple the bonding pads and the bond fingers after the dummy wires are formed.