Module Board Cavity Resin Sealing for Small Pitch Components
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Solution Overview
Problem
Existing module boards face connection failures due to positional variations of circuit patterns and electronic components during thermocompression bonding, limiting the mounting of components with small terminal pitches and insufficient resin supply for cavity filling.
Innovation Solution
A module board design featuring a first board with an electronic component mounted on one surface and a second board with a hole to house the component, where resin layers are formed on both surfaces to seal the component within the cavity, allowing for increased reliability and packaging density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermocompression bonding is used to bond the resin film to the core board, then the electronic component can be housed in the cavity, but the position of the circuit pattern and the electronic component may vary causing connection failure
Solution Approach 1:
The circuit pattern is formed on the resin film before bonding to the core board. This preliminary formation of the circuit pattern allows for precise positioning to be established prior to the thermocompression bonding process, preventing position variation during bonding.
Solution Approach 2:
A jig is introduced as an intermediary tool during the thermocompression bonding process. The jig holds both the resin film and core board in precise alignment, preventing position variation of the circuit pattern and electronic component during bonding.
2Manufacturing precision
If the circuit pattern on the resin film is made large to prevent connection failure, then position variation tolerance is increased, but electronic components with small terminal pitches cannot be housed in the cavity
Solution Approach 1:
The circuit pattern is formed on the resin film before bonding with precise positioning. This preliminary precision allows the circuit pattern to be made smaller while still ensuring accurate connection, thereby freeing up cavity space for electronic components with small terminal pitches.
Solution Approach 2:
A positioning jig is used as an intermediary during bonding to ensure precise alignment of the circuit pattern with the core board. This external positioning aid allows the circuit pattern itself to be smaller while maintaining connection accuracy.
3Device complexity
If the resin film is used to supply resin for filling the cavity, then the bonding process is simplified, but the resin supply amount is insufficient for filling the cavity
Solution Approach 1:
The resin supply system is segmented into two sources: the resin film bonded to the core board provides initial resin, and an additional resin supply mechanism provides the remaining resin needed to fill the cavity. This segmentation allows sufficient resin supply while maintaining process simplicity.
Solution Approach 2:
The resin film is bonded to the core board in advance, providing a preliminary resin source. Then, additional resin is supplied to complete the cavity filling. This two-stage preliminary action ensures sufficient resin supply without overly complicating the process.
4Volume of moving object
If the electronic component thickness is larger than the cavity depth, then the component cannot be housed in the cavity, but reducing the cavity depth increases module board height
Solution Approach 1:
The electronic component is positioned at an angle relative to the core board rather than perpendicular to it. This angular positioning allows the component to be housed in the cavity even when its thickness exceeds the cavity depth, while maintaining a compact module board height.
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 the mounting of components with small terminal pitches, increases reliability by sealing the component with resin, and allows for a decrease in module board height while maintaining or increasing packaging density.
Implementation Method 1
Resin layers are provided on both the first principal surface and a second principal surface of the second board, and the inside of the hole is filled with resin
Data Source
AI summary
In a method of manufacturing a module board, an electronic component is mounted on a first principal surface of a small board. A cavity defining a through hole is formed in a core board. The electronic component is housed in the cavity by mounting the small board on a surface electrode arranged around the cavity. Resin layers are formed on both principal surfaces of the core board, and resin flows through a gap between the core board and the small board. Hence, the inside of the cavity is filled with the resin, and the electronic component is sealed with the resin.