Circuit Board Thermal Segmentation for Wire Bonding
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Solution Overview
Problem
Existing imaging unit technologies face challenges in wire bonding connections between a mount board and electronic devices, as the high temperature required for bonding can damage sensitive electronic components on the board, which lack heat resistance.
Innovation Solution
A method and module design that utilize a circuit board with distinct metal patterns and electrodes on either side, where the electronic device is heated through a thermal conductive path while isolating sensitive components from direct heat exposure, using a board support stage to manage heat transfer effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is performed at high temperature (above 150°C) to form high quality alloy state, then connection quality is improved, but electronic components mounted on the mount board are damaged due to heat
Solution Approach 1:
The mount board is divided into two distinct metal patterns: a first metal pattern (heating region) that directly contacts the electronic device to be heated, and a second metal pattern (non-heating region) that contacts electronic components but is thermally isolated. This segmentation allows selective heating of only the electronic device while protecting sensitive components from heat damage.
Solution Approach 2:
Different regions of the mount board are assigned different thermal properties. The first metal pattern region has high thermal conductivity to efficiently heat the electronic device, while the second metal pattern region is thermally isolated (through insulation or lower thermal conductivity) to protect electronic components. This creates local quality differences in heat resistance and thermal conductivity across the board.
2Temperature
If the entire mount board is heated uniformly, then all components reach bonding temperature, but heat-resistant components are damaged and non-heat-resistant components cannot be used
Solution Approach 1:
The mount board is segmented into a heating region (first metal pattern) and a non-heating region (second metal pattern) to enable selective temperature control. This allows the electronic device to reach bonding temperature while electronic components remain at lower temperatures, expanding compatibility to include both heat-resistant and non-heat-resistant components in the same assembly.
Solution Approach 2:
A board support stage is introduced as an intermediary element that physically supports the mount board during wire bonding while preventing direct heat transfer to the second metal pattern region. This intermediary structure enables thermal isolation, allowing the heating region to reach high temperatures without necessarily heating the entire board, thus protecting temperature-sensitive components.
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 wire connection between the mount board and electronic device while preventing damage to sensitive components by efficiently heating the device without excessively raising the temperature of the components, allowing for the use of components with lower heat resistance.
Implementation Method 1
the electronic device is heated by transferring heat supplied to the second metal pattern to the electronic device via the first metal pattern
Data Source
AI summary
A method includes preparing a circuit board that includes a first metal pattern over a first face side of the substrate, a first electrode in a periphery of the first metal pattern, a second electrode over a second face side of the substrate, and a second metal pattern thermally connected to the first metal pattern and in which an electronic device is fixed on the first metal pattern and an electronic component is electrically connected to the second electrode, and connecting the first electrode and a third electrode of the electronic device by a bonding wire with the electronic device being heated. By a board support stage, the electronic device is heated by transferring heat to the electronic device via the second and then first metal pattern with the circuit board being supported to form a space including the electronic component between the second face and the board support stage.