Circuit Board Trench Plating to Block Solder Grain Short Circuits
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Solution Overview
Problem
Existing semiconductor devices face issues with unexpected short circuits between wires connected to the circuit board due to scattered solder grains during the manufacturing process.
Innovation Solution
A trench is formed along the peripheral edge of the electrode on the circuit board, and a plated layer with low wettability to solder is applied to the inner wall of the trench to capture and prevent solder grains from reaching the wiring layers, thereby preventing short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder is applied to connect passive components to the circuit board, then electrical connections are established, but solder grains may scatter and cause short circuits between wires
Solution Approach 1:
The circuit board is segmented by forming trenches that divide the board into separate regions. These trenches physically partition the space around electrodes, creating isolated zones that prevent scattered solder grains from traveling between adjacent wiring layers and causing short circuits.
Solution Approach 2:
A plated layer with low wettability to solder is introduced as an intermediary substance on the trench inner walls. This plated layer acts as a barrier that repels solder grains, preventing them from adhering to the trench surfaces and migrating to adjacent wiring layers, thus eliminating the short circuit hazard while maintaining connection reliability.
2Reliability
If trenches are formed and plated layers are applied to prevent solder grain scattering, then short circuit prevention is achieved, but manufacturing process complexity increases
Solution Approach 1:
The trenches are formed and plated layers are applied in advance, before the soldering process occurs. This preliminary preparation ensures that the protective barriers are already in place to capture any scattered solder grains, eliminating the need for additional post-soldering inspection or repair steps and simplifying the overall manufacturing flow.
Solution Approach 2:
The plated layer's low wettability to solder, which initially seems like a limitation, is converted into a beneficial property. This characteristic causes solder grains to be repelled and captured within the trench regions, transforming the potential harm of scattered solder into a protective mechanism that prevents short circuits.
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
The solution effectively captures and contains solder grains, preventing them from causing short circuits during reflow treatment and ensuring reliable electrical connections between the semiconductor chip and passive components.
Implementation Method 1
a plated layer with low wettability to solder is applied to the inner wall of the trench to capture and prevent solder grains from reaching the wiring layers
Data Source
AI summary
A semiconductor device, a circuit board, and a semiconductor device manufacturing method, capable of preventing an unexpected short circuit between wires connected to the circuit board are provided. The semiconductor device comprises: a circuit board including a first surface and a second surface on an opposite side of the circuit board as the first surface; a semiconductor chip provided on the first surface of the circuit board; a passive component connected to an electrode that is provided on the first surface of the circuit board via solder; and sealing resin covering the first surface of the circuit board and surfaces of the semiconductor chip and the passive component. A trench is formed through the first surface of the circuit board along at least a part of a peripheral edge of the electrode, and a plated layer is formed on an inner wall of the trench.