Coated Bonding Wires for High-Density IC Packages
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Solution Overview
Problem
Conventional wire bonding packaging techniques face issues with bonding wire sweep during encapsulation, leading to shorting between adjacent wires due to deformation under plastic molding compound pressure, requiring additional process steps or specialized equipment to mitigate.
Innovation Solution
The use of insulator-coated bonding wires, where an insulating material, typically an epoxy resin with low filler content, is applied to the wires to provide mechanical support and prevent shorting, and is encapsulated along with the semiconductor die within a molding compound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional wire bonding packaging technique is used with increasing number of I/O terminal pads, then higher density IC packages are achieved, but bonding wire sweep and shorting between adjacent wires occur due to deformation under molding compound pressure
Solution Approach 1:
An insulating material is introduced as an intermediary substance between adjacent bonding wires. This insulating material prevents direct contact and shorting between wires while allowing the wires to deform under molding pressure without causing electrical failure. The insulating material acts as a mediator that maintains electrical isolation despite mechanical deformation.
Solution Approach 2:
The insulating material is applied to bonding wires before the molding process. This pre-application provides protective cushioning that prevents wire sweep and shorting during the subsequent encapsulation process. The insulation is in place beforehand to cushion against the deforming forces that will be applied during molding.
2Manufacturing precision
If approaches are suggested for reducing bonding wire sweep during encapsulation, then wire deformation is reduced, but additional process steps or specialized equipment are required which increase production costs
Solution Approach 1:
The insulating material application is merged with the existing wire bonding process flow. The insulating material can be applied using standard coating equipment already present in most packaging facilities, and the process is integrated into the normal packaging sequence without requiring specialized wire protection equipment or separate processing stations.
Solution Approach 2:
The solution changes the physical-chemical parameters of the bonding wire system by adding an insulating coating layer. This parameter change (adding insulation) provides wire sweep protection without changing the fundamental wire bonding process parameters such as wire tension, bonding temperature, or molding pressure, thereby avoiding the need for specialized equipment.
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 solution effectively reduces wire sweep and prevents shorting, allowing for higher density IC packages without the need for additional process steps or specialized equipment, thereby reducing production costs and enhancing wire isolation.
Implementation Method 1
an insulating material, typically an epoxy resin with low filler content, is applied to the wires
Implementation Method 2
a molding compound covering the top surface and encapsulating the semiconductor die, the plurality of bonding wires, and the insulating material
Data Source
AI summary
A semiconductor package includes a carrier substrate having a top surface, a semiconductor die mounted on the top surface, a plurality of bonding wires connecting the semiconductor die to the carrier substrate, an insulating material coated on the bonding wires, and a molding compound covering the top surface and encapsulating the semiconductor die, the plurality of bonding wires, and the insulating material.