Wire Bonding Motion Profiles for Thermal Load Reliability Testing
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Solution Overview
Problem
Existing wire bonding methods lack effective testing methods to assess the reliability and robustness of bonded wires prior to their use in semiconductor devices, particularly under thermal loads, which can lead to wire damage and failure over time.
Innovation Solution
A method involving a wire bonding machine that simulates thermal reliability tests by moving a bond head along a motion profile to test bonded wires, generating test data on wire loop shapes and selecting optimal shapes based on predetermined criteria for subsequent bonding operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire loops are formed using wire bonding machines, then electrical interconnection between die pad and leadframe is achieved, but the wire loops may become damaged or fail over the device lifetime due to thermal load
Solution Approach 1:
The patent applies preliminary action by performing wire loop testing and selection before the device is subjected to thermal load in actual operation. The method pre-identifies robust wire loops that can withstand thermal cycling, thereby preventing future failures. This is achieved through automated testing sequences that simulate thermal effects and mechanically stress the wire bonds prior to final device assembly.
Solution Approach 2:
The patent implements preliminary anti-action by proactively identifying and eliminating weak wire loops before they can fail under thermal stress. The testing methodology applies opposing forces and thermal simulation to counteract potential failure modes, allowing defective bonds to be detected and rejected before they compromise device reliability during operation.
2Reliability
If traditional wire bonding testing methods are used, then basic bond formation is confirmed, but comprehensive reliability testing under thermal and mechanical stress is not performed
Solution Approach 1:
The patent applies universality by designing a wire bonding machine with integrated multi-functional capabilities. The same wire bonding tool is used for both forming wire loops and performing comprehensive reliability testing, including thermal simulation and mechanical stress application. This eliminates the need for separate specialized testing equipment, reducing overall system complexity while achieving thorough reliability assessment.
Solution Approach 2:
The patent merges the wire bonding process with reliability testing into a single integrated operation. The bonding machine simultaneously performs bond formation, wire loop shaping, thermal cycling simulation, and mechanical stress testing. This consolidation allows comprehensive reliability evaluation without requiring additional separate testing steps, thereby managing complexity while improving reliability assessment.
3Reliability
If extensive wire loop testing is performed to ensure reliability, then robust wire bonds are identified, but time is consumed in the testing process
Solution Approach 1:
The patent applies skipping by implementing rapid automated testing sequences that quickly evaluate wire loop robustness. The methodology uses efficient motion profiles and accelerated thermal cycling protocols to perform comprehensive reliability testing in minimized time. Weak wire loops are rapidly identified and eliminated through high-speed mechanical and thermal stress application, reducing overall testing duration while maintaining reliability assessment accuracy.
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 allows for rapid assessment of bonded wire reliability and robustness, reducing the need for actual thermal testing and enabling the selection of robust wire loop shapes for improved performance in semiconductor devices.
Implementation Method 1
varying types of bonding energy may be used, including, for example, ultrasonic energy, thermosonic energy
Implementation Method 2
varying types of bonding energy may be used, including, for example, ultrasonic energy, thermosonic energy
Implementation Method 3
moving the wire bonding tool along a motion profile after step (b), with the wire engaged with the wire bonding tool to test the wire
Implementation Method 4
Simulates thermal and mechanical stress on bonded wires efficiently
Data Source
AI summary
A method of testing a bonded wire on a wire bonding machine is provided. The method includes the steps of: (a) bonding a portion of a wire to a bonding location using a wire bonding tool on a wire bonding machine to form a bonded portion of the wire; (b) moving the wire bonding tool away from the bonded portion of the wire after step (a) with the wire engaged with the wire bonding tool; and (c) moving the wire bonding tool along a motion profile after step (b), with the wire engaged with the wire bonding tool to test the wire.