Semiconductor Package Screw Pressing for Substrate Warp Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices experience warping due to thermal stress from differences in thermal expansion coefficients between chips and substrates, leading to gaps or voids with coolers, increasing thermal resistance and risking overheating and performance deterioration.
Innovation Solution
A semiconductor device design with a case housing and screw mechanism that adjusts substrate deformation by screwing a tip into the substrate to correct warping, ensuring minimal gaps and voids with a cooler via a thermal interface material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If chips are mounted on a substrate, then the substrate may warp due to thermal stress, but providing recesses or tubular members increases device complexity
Solution Approach 1:
The screw mechanism allows dynamic adjustment of the substrate's position and flatness. By rotating the screw, the pressing member can apply varying forces to correct warping, transforming a static structure into a dynamically adjustable one that adapts to thermal expansion changes
Solution Approach 2:
The case is divided into multiple functional components: the pressing member for applying force, the screw mechanism for adjustable control, and the support structure for stability. This segmentation allows each component to perform its specific function efficiently while maintaining overall simplicity
2Temperature
If screws are inserted through the substrate to attach a cooler, then thermal contact is improved, but the substrate may be damaged or warping increased
Solution Approach 1:
A pressing member acts as an intermediary between the screw and the substrate. Instead of the screw directly contacting and potentially damaging the substrate, the pressing member distributes the force evenly across the substrate surface, protecting it while still achieving the desired thermal contact
Solution Approach 2:
The direct mechanical fastening method (screws through substrate) is replaced with an indirect pressing mechanism. The screw provides adjustable pressure through the pressing member, substituting a potentially damaging mechanical insertion with a gentler pressing action that maintains substrate integrity
3Strength
If the substrate warps, then gaps or voids form with the cooler, but increasing pressing force may damage the substrate
Solution Approach 1:
The screw mechanism enables dynamic control of pressing force. The operator can gradually increase the pressure to the minimum level needed to eliminate gaps, avoiding excessive force that could damage the substrate. This dynamic adjustment capability allows precise control of the contact pressure
Solution Approach 2:
The pressing member serves as a cushioning element between the screw and substrate. It distributes and softens the applied force, preventing sudden or concentrated stress that could damage the substrate while still providing sufficient pressure to eliminate gaps
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 effectively reduces thermal resistance and prevents overheating by maintaining consistent contact between the substrate and cooler, enhancing heat dissipation and preventing semiconductor element deterioration.
Implementation Method 1
the substrate may warp to become upwardly convex when the chip mounting surface side is regarded as the 'upper surface' due to thermal stress caused by differences in the coefficient of thermal expansion between the chips and the substrate
Implementation Method 2
ensuring minimal gaps and voids with a cooler via a thermal interface material
Data Source
AI summary
A semiconductor device includes an insulated substrate, a semiconductor element mounted on a first main surface side of the insulated substrate, and a case housing that houses the insulated substrate and the semiconductor element so that a second main surface side of the insulated substrate is exposed. The outer circumferential portion of the insulated substrate is bonded to the case housing. The case housing is provided with a screw hole at a position facing the first main surface side of the insulated substrate. The semiconductor device further includes a screw that is screwed into a screw hole in the case housing and has a tip portion that contacts the first main surface side of the insulated substrate.