Semiconductor Package Surface Roughness for Thermal Medium Retention

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Solution Overview

Problem

Existing semiconductor devices face challenges in effectively dissipating heat due to the repeated expansion and contraction of the support member, leading to potential discharge of heat transfer medium and insufficient heat dissipation, which can impact the performance and reliability of the device.

Innovation Solution

The semiconductor device incorporates a support member with a first uneven region on its surface and a sealing member with a second uneven region, both with specific surface roughness, to prevent the discharge of heat transfer medium by enhancing thermal contact and improving heat dissipation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a flat support member surface is used, then the device structure is simple, but heat transfer medium discharges during thermal expansion and contraction

Engineering Contradiction:

Improvesupport member structureVSAvoidheat transfer medium retention

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The support member surface is designed with localized uneven regions rather than a completely flat or entirely complex structure. These uneven regions are specifically positioned at the heat transfer medium storage portion to prevent discharge, while maintaining simplicity in other areas. This local modification resolves the contradiction by adding only the necessary complexity where needed.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The uneven regions on the support member surface feature curved or rounded profiles rather than sharp edges. This curvature design allows the heat transfer medium to be retained in the凹陷 portions during thermal cycling, preventing discharge while maintaining manufacturing feasibility. The curved geometry effectively addresses the reliability issue without requiring complex structural modifications.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Ease of manufacture

If a flat sealing member surface is used, then the manufacturing process is simple, but thermal contact is insufficient leading to poor heat dissipation

Engineering Contradiction:

Improvesealing member fabricationVSAvoidheat dissipation efficiency

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The sealing member is designed with uneven regions localized at its outer peripheral surface, specifically where thermal contact with the heat sink is required. This localized surface modification improves thermal contact without complicating the entire sealing member structure, thus maintaining ease of manufacture while enhancing heat dissipation performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The uneven regions on the sealing member incorporate curved surface profiles that enhance contact with the heat sink surface. These curved geometries adapt to surface variations and improve thermal coupling, achieving better heat dissipation without requiring complex manufacturing processes for the entire component.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Duration of action of moving object

If the support member undergoes repeated thermal expansion and contraction, then the device operates under normal thermal cycles, but heat transfer medium discharges and heat dissipation becomes insufficient

Engineering Contradiction:

Improvethermal cycle enduranceVSAvoidheat dissipation consistency

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The uneven regions are designed in advance to accommodate the effects of thermal expansion and contraction. During normal thermal cycling, the heat transfer medium can move into and out of these pre-designed uneven regions without discharging, as the uneven geometry provides a buffer zone. This beforehand design ensures reliable heat dissipation consistency throughout the device's operational lifetime.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 uneven surface structures effectively suppress the discharge of heat transfer medium, ensuring consistent heat dissipation and improved performance of the semiconductor device even under repeated thermal cycles.

Implementation Method 1

both with specific surface roughness, to prevent the discharge of heat transfer medium by enhancing thermal contact and improving heat dissipation efficiency

Methodology Applied

Scientific EffectThermal contact: Conduction (thermal)

Implementation Method 2

ensuring consistent heat dissipation and improved performance of the semiconductor device even under repeated thermal cycles

Methodology Applied

Scientific EffectHeat absorption: Absorption (physical)

Data Source

PatentUS20260047450A1Semiconductor device and method for manufacturing semiconductor device

Publication Date: 2026.02.12 ROHM CO LTD

AI summary

A semiconductor device includes a support member, a semiconductor element and a sealing member. The semiconductor element is disposed on a first side in a thickness direction relative to the support member. The sealing member covers a part of the support member and the semiconductor element. The support member has a first surface facing a second side in the thickness direction and exposed from the sealing member. The first surface is formed with a first uneven region. In an example, the first uneven region has an arithmetic mean roughness between 0.2 μm and 13 μm. In an example, the first uneven region includes a plurality of uneven lines in an arc shape.