Multi-Wire Bonding with Current Sensing for Junction Temperature Reduction
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Solution Overview
Problem
Semiconductor packages face issues with increasing surface resistance and junction temperature at the bond wires due to thermal cycling, leading to potential joint failure and package shorts, especially when using aluminum materials.
Innovation Solution
The implementation of a semiconductor package system that uses multiple bond wires, including a first bond wire coupled to a power source or ground and a second bond wire to a control integrated circuit, with the current sense area on a leadframe or substrate, allowing current measurement and dividing the total current among these wires to reduce junction temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single bond wire is used to carry total current, then the electrical connection is simple, but the junction temperature increases and reliability decreases
Solution Approach 1:
The patent divides the total current path into multiple parallel bond wires (first bond wire, second bond wire, and at least a third bond wire). Each wire carries a portion of the total current, reducing the current density and junction temperature at each bonding interface. This segmentation of the current path directly addresses the thermal management problem while maintaining electrical connectivity.
2Temperature
If multiple bond wires are used to divide current, then junction temperature is reduced, but the device complexity increases
Solution Approach 1:
The patent makes the second bond wire serve dual functions: it provides an electrical connection for current carrying (like the first and third wires) and simultaneously serves as a current sense path for the control integrated circuit. The control IC measures the voltage drop across the second bond wire to monitor current flow. This multi-functionality reduces device complexity by eliminating the need for separate sensing wires or additional sensing circuitry.
3Measurement precision
If current is measured using traditional methods, then current monitoring is achieved, but additional components increase device complexity
Solution Approach 1:
The patent merges the current sensing function with the existing bond wire structure. The second bond wire is used both for current conduction and for sensing purposes. The control integrated circuit measures the voltage drop across the second bond wire to determine current flow, eliminating the need for separate current sense resistors or additional measurement components. This integration reduces device complexity while maintaining measurement capability.
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 significantly extends the power cycle lifetime of the semiconductor package by reducing junction temperature and preventing bond wire failure, as demonstrated by test results showing increased reliability and longer package lifespan without additional thermal management.
Implementation Method 1
the control integrated circuit may be configured to use the second bond wire and the current sense area to measure a current flowing through the first bond wire during operation
Implementation Method 2
The junction temperature between the pad and the first bond wire and the at least third bond wire may be reduced by dividing the total current with the first bond wire and the at least third bond wire
Data Source
AI summary
Implementations of a semiconductor package system may include a first bond wire bonded to a portion of a leadframe and to a pad of a semiconductor die, the first bond wire coupled to one of a power source or a ground; and a second bond wire bonded to the portion of the leadframe and to a control integrated circuit. The portion of the leadframe may form a current sense area and the control integrated circuit may be configured to use the second bond wire and the current sense area to measure a current flowing through the first bond wire during operation.