Resin-Embedded Solder Bump Layout to Prevent Mounting Open Defects
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Solution Overview
Problem
Existing circuit modules experience open defects during mounting due to gas accumulation in gaps between solder bumps and resin layers, leading to separation of solder bumps and substrate connections.
Innovation Solution
A circuit module design where the gap between the resin layer and solder bump satisfies the inequality Y×(X/100) > V1, ensuring thermal expansion of the solder bump fills the gap, preventing gas accumulation and maintaining a secure connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder bumps are surrounded by a resin layer with gaps between them, then the resin layer provides insulation and structural support, but gas generated from the solder bumps during mounting accumulates in the gaps and causes open defects
Solution Approach 1:
The patent changes the physical parameters of the gap by controlling its width to satisfy a specific inequality relationship. The gap width is designed to be within a specific range relative to the solder bump diameter, ensuring that the gap is narrow enough to prevent gas accumulation while maintaining electrical insulation. This parameter optimization resolves the contradiction between providing insulation support and preventing gas-related defects.
Solution Approach 2:
The patent designs the gap dimensions to allow gas to quickly pass through or be displaced during the mounting process. By controlling the gap width to be sufficiently narrow, the gas generated from solder bumps can be rapidly expelled from the gap region before it can accumulate to problematic levels, thus preventing open defects while maintaining the necessary insulation structure.
2Object-generated harmful factors
If the gap between resin layer and solder bump is reduced, then gas accumulation is prevented, but the resin layer's ability to provide insulation and structural support is compromised
Solution Approach 1:
The patent identifies and optimizes specific dimensional parameters of the gap, establishing a quantitative relationship between gap width and solder bump diameter through the inequality formula. This parameter optimization allows the gap to be narrow enough to prevent gas accumulation while remaining wide enough to maintain the resin layer's insulating and structural functions, thus resolving the contradiction between preventing harmful gas effects and maintaining structural integrity.
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 design significantly reduces the likelihood of open defects by allowing gas to escape outside the solder bump, ensuring reliable substrate connections during mounting.
Implementation Method 1
X represents a coefficient of thermal expansion (%) upon heating the solder bump from 25° C. to 220° C.
Data Source
AI summary
A circuit module 1 includes: a substrate 11 including a first main surface 11a and a second main surface 11b; a resin layer 31 on the first main surface 11a of the substrate 11; a penetrating portion 40 penetrating the resin layer 31 in a thickness direction; and a solder bump 50 partially present in the penetrating portion 40. The circuit module 1, in a cross section including the penetrating portion 40 and the solder bump 50, taken along the thickness direction, satisfies an inequality (1) below:Y×(X/100)>V1 (1)wherein V1 represents an area of a gap 60 between the resin layer 31 and the solder bump 50, X represents a coefficient of thermal expansion (%) upon heating the solder bump 50 from 25° C. to 220° C., and Y represents an area of the solder bump 50.