Wire Bond Continuity Testing Using a Conductive Wire Cutter
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Solution Overview
Problem
In-process testing of wire bonds is challenging due to the inability to effectively determine the success or failure of wire bonds during the bonding process, leading to potential electrical resistance issues and functionality problems in device assemblies.
Innovation Solution
A wire bonding apparatus equipped with a supply of bond wire, a wire bonding head featuring an electrically conductive wire cutter, and an electrical continuity tester, which measures resistance between the contact surface and the bond wire supply to determine the success or failure of wire bonds by comparing measured resistance to threshold values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonds are formed without in-process testing, then the bonding process is simple and fast, but electrical resistance issues and functionality problems occur due to improperly formed bonds
Solution Approach 1:
The wire bonding apparatus merges the wire bonding head with an electrical continuity tester and wire cutter into a single integrated system. The continuity tester is coupled between the bond wire supply and wire cutter, allowing simultaneous bonding and testing operations without requiring separate testing equipment, thus improving reliability while controlling complexity.
Solution Approach 2:
The wire bonding head is designed to perform multiple functions: forming wire bonds, cutting excess wire, and testing electrical continuity. The wire cutter is made electrically conductive so it can serve both as a mechanical cutting tool and as an electrical contact for resistance measurement, eliminating the need for separate testing components.
2Measurement precision
If an electrical continuity tester is added to the wire bonding apparatus, then wire bond success can be determined in real-time, but the apparatus becomes more complex
Solution Approach 1:
The wire cutter is designed to be electrically conductive, allowing it to serve dual purposes: mechanical wire cutting and electrical contact for resistance measurement. This eliminates the need for separate testing components and reduces overall apparatus complexity while enabling precise resistance measurements.
Solution Approach 2:
The electrical continuity tester is integrated into the wire bonding head assembly, combining bonding, cutting, and testing functions in one unit. The tester is coupled between the bond wire supply and wire cutter, allowing all operations to occur through a single apparatus structure rather than requiring multiple separate devices.
3Reliability
If resistance measurement is performed during wire bonding, then improper bonds can be detected early, but the bonding process time increases
Solution Approach 1:
The electrical continuity tester operates continuously during the wire bonding process, measuring resistance in real-time without interrupting the bonding workflow. The tester is coupled between the bond wire supply and wire cutter, allowing simultaneous bonding and testing operations to occur without stopping the process, thus maintaining productivity while enabling continuous defect detection.
Solution Approach 2:
The system performs resistance measurement during the bonding process itself, allowing defects to be detected before the bonding cycle completes. This preliminary detection enables immediate identification of improper bonds without requiring separate post-bonding testing steps, preventing rework and maintaining process speed.
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
Enables real-time determination of wire bond success or failure, preventing unwanted electrical resistance and functionality issues by ensuring proper bond formation through in-process testing.
Implementation Method 1
measuring, with a continuity tester included in the wire bonding apparatus, a resistance between the contact surface and the supply of bond wire
Data Source
AI summary
In a general aspect, a wire bonding apparatus can include a supply of bond wire, a wire bonding head, and an electrical continuity tester. The wire bonding head can including a wire cutter. The wire cutter can be electrically conductive. The electrical continuity tester can be coupled between the supply of bond wire and the wire cutter.