Multilayered Circuit Substrate Thermal Stress Reduction
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Solution Overview
Problem
Semiconductor element built-in multilayered circuit boards face challenges with heat dispersion and electrical connection due to differences in linear expansion coefficients between insulating substrates and semiconductor elements, leading to stress concentration, warping, and instability, especially as circuit complexity and density increase.
Innovation Solution
A semiconductor element built-in multilayered circuit board design featuring an insulating substrate with a low linear expansion coefficient difference from the semiconductor element, using high thermal conductivity ceramics like aluminum nitride, and a structure with recesses, through-holes, and conductive paths for efficient heat dissipation and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resin insulating substrate is used in a semiconductor element built-in multilayered circuit board, then the manufacturing process is simple and cost-effective, but the linear expansion coefficient difference between the substrate and semiconductor element causes stress concentration, warping, and instability
Solution Approach 1:
The patent changes the material parameter of the insulating substrate from resin to ceramic, specifically selecting ceramic materials with linear expansion coefficients between 4.0-7.0×10^-6/K that closely match semiconductor elements. This parameter change resolves the expansion mismatch issue while maintaining manufacturing feasibility through established ceramic substrate processes
Solution Approach 2:
The patent employs ceramic composite materials that combine appropriate linear expansion coefficients with good electrical insulation properties and thermal conductivity. The ceramic substrate acts as a composite structure that simultaneously addresses thermal management, mechanical stability, and electrical isolation requirements
2Productivity
If the wiring number increases to improve operating rate and consumption power, then the circuit functionality is enhanced, but the heat value per unit area increases and heat dispersion becomes more difficult
Solution Approach 1:
The patent replaces the conventional resin-based thermal management system with a ceramic substrate that provides inherent thermal conduction capabilities. The ceramic material's thermal conductivity naturally dissipates heat without requiring additional active cooling mechanisms, effectively managing the increased heat load from higher wiring density
Solution Approach 2:
The patent changes the thermal conductivity parameter of the substrate material from low (resin) to high (ceramic). This parameter change enables the substrate to actively participate in heat dissipation, converting the substrate from a thermal barrier to a thermal management component that can handle increased power density
3Volume of moving object
If the heat dispersion face is reduced through miniaturization, then the device size is reduced, but the heat value per unit area increases significantly
Solution Approach 1:
The patent changes the thermal conductivity parameter of the substrate material to compensate for the reduced heat dispersion area. The high thermal conductivity of ceramic materials allows efficient heat spread across the smaller substrate area, maintaining effective thermal management despite miniaturization
Solution Approach 2:
The patent applies local quality enhancement by using ceramic materials with superior thermal conductivity specifically in the substrate layer where heat generation occurs. This localized material optimization addresses the heat dissipation challenge in the critical heat-generating region without increasing overall device size
4Productivity
If semiconductor elements are densely packaged to reduce device size, then the integration density is improved, but the linear expansion coefficient difference causes adherence inhibition and instability
Solution Approach 1:
The patent changes the linear expansion coefficient parameter of the substrate material to match that of semiconductor elements. This parameter matching eliminates thermal stress during temperature cycles, ensuring stable adherence of densely packaged elements without requiring additional bonding complexity
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
This design ensures stable operation by minimizing thermal stress, preventing warping, and enabling high-density, high-speed packaging with improved reliability and heat dissipation, while maintaining precise alignment and preventing adherence issues between semiconductor elements and substrates.
Implementation Method 1
the insulating substrate is a high thermal conductive ceramic
Implementation Method 2
a difference between a linear expansion coefficient of the insulating substrate and a linear expansion coefficient of the semiconductor element in a temperature zone of 20-300° C. is less than 1×10−5/K
Data Source
AI summary
For the purpose of providing a semiconductor element built-in type multilayered circuit board in which a semiconductor element is closely joined to a recess of an insulating substrate to effectively disperse heat generated from the semiconductor element through the insulating substrate at a working temperature region of the semiconductor element circuit board, to surely conduct an electrical connection of an electronic part such as semiconductor element or the like in a short wiring and to enable the high density mounting of semiconductor elements, miniaturization and increase of working speed, there is proposed a semiconductor element built-in type multilayered circuit board formed by laminating a plurality of semiconductor element built-in type boards each comprising an insulating substrate and a semiconductor element accommodated in a recess formed therein, characterized in that a difference between a linear expansion coefficient of the insulating substrate and a linear expansion coefficient of the semiconductor element in a temperature zone of 20-300° C. is less than 1×10−5/K.