Segmented Heat Dissipation Block for Semiconductor Modules

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Solution Overview

Problem

Conventional semiconductor device modules face challenges in precision alignment of heat dissipation blocks due to dimensional variations, leading to potential damage during resin sealing, and grinding performance issues due to clogging of diamond grinding wheels when exposing buried heat dissipation blocks, resulting in quality defects and reduced productivity.

Innovation Solution

Incorporating heat dissipation blocks made of two different hardness materials, with a harder material portion exposed and a softer thermal conductivity portion in contact with devices, and optionally using dummy blocks of higher height and hardness to facilitate precise exposure and grinding without clogging the grinding wheel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heat dissipation blocks made of soft material are used for efficient heat dissipation, then thermal conductivity is improved, but grinding wheel clogging occurs leading to quality defects and reduced productivity

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidgrinding wheel performance

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The heat dissipation block is segmented into two distinct material regions: a soft material portion (high thermal conductivity) for heat dissipation and a hard material portion (grindable) for exposure. This segmentation allows each portion to fulfill its specific function without compromising the other, resolving the contradiction between heat dissipation efficiency and grinding wheel performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the heat dissipation block are assigned different material properties: the portion in contact with devices uses soft material for optimal thermal conductivity, while the exposed portion uses hard material for easy grinding. This local differentiation of material quality enables simultaneous achievement of heat dissipation efficiency and manufacturing productivity.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If dimensional tolerances are relaxed for easier manufacturing, then manufacturing complexity is reduced, but alignment precision of heat dissipation blocks deteriorates

Engineering Contradiction:

Improvemanufacturing toleranceVSAvoidalignment precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the material parameter (hardness) of the heat dissipation block rather than relying on tight dimensional tolerances. By making the exposed portion hard and easily grindable, the system compensates for alignment variations, allowing relaxed manufacturing tolerances while maintaining functional precision through post-assembly grinding.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If heat dissipation blocks are buried in molding resin to prevent device damage, then device reliability is improved, but grinding performance decreases due to clogging

Engineering Contradiction:

Improvedevice protectionVSAvoidgrinding quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The heat dissipation block is segmented into soft material portion (buried in resin for device protection) and hard material portion (exposed for grinding). This segmentation allows the block to be buried in molding resin to prevent device damage during sealing, while the exposed hard portion maintains good grinding performance without clogging the grinding wheel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The heat dissipation block uses composite construction with two different materials: soft material for thermal conductivity and hard material for grindability. This composite structure enables the block to be embedded in resin for protection while maintaining excellent grinding characteristics, resolving the contradiction between device reliability and manufacturing precision.

Inventive Principle:

Principle #40Composite materials

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 approach maintains grinding wheel performance, prevents quality defects like burrs and chipping, and enhances productivity by stabilizing product quality and reducing the need for frequent dressing of the grinding wheel.

Implementation Method 1

grinding the surface of the molded resin with a grinding wheel such as a diamond grinding wheel

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

metal heat dissipation blocks having a high thermal conductivity is incorporated to dissipate externally from the module the heat generated during operation of the devices

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20230215778A1Semiconductor device module and method for manufacturing same

Publication Date: 2023.07.06 MITSUBISHI ELECTRIC CORP

AI summary

A semiconductor device module includes a device mounted on the surface of an organic substrate; a heat dissipation block bonded and fixed to the surfaces of the device; and a molded resin sealing the device with at least one surface of the heat dissipation block being exposed. The heat dissipation block includes a first portion and a second portion made of materials different in hardness: the first portion is harder than the second portion, and a gradient in hardness from the first portion on the side exposed from the molded resin to the second portion on the side bonded to the device, to keep a good grinding performance of grinding wheel.