Semiconductor Device Metal Base Plate Deformation Control

Solution Overview

Problem

Conventional semiconductor devices experience deformation and cracking of insulating layers during transfer molding due to pressure, leading to reduced insulation properties and reliability, especially when metal base plates with projections and depressions are resin-molded.

Innovation Solution

A semiconductor device design featuring a metal base plate with projections and depressions on its lower surface, surrounded by a projecting peripheral portion, an insulating layer on the upper surface, and a metal layer, where the insulating layer is sealed with a resin to prevent resin leakage and deformation, and heat dissipation fins are inserted into the depressions for enhanced heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a metal base plate with projections and depressions is resin-molded by transfer molding, then mass productivity is improved, but the metal base plate deforms due to temperature and pressure causing cracks in the insulating layer

Engineering Contradiction:

Improvemass productivityVSAvoidelectrical reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The die is pre-formed with an engraved structure that includes a peripheral portion extending beyond the projections. This preliminary structural preparation prevents resin leakage and eliminates the need for clearance gaps, thereby preventing metal base plate deformation and insulating layer cracks during the transfer molding process while maintaining mass productivity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The engraved peripheral portion of the die acts as an intermediary structure between the resin and the projections. It controls resin flow and prevents direct pressure concentration on the projections, thereby preventing metal base plate deformation and insulating layer damage during molding

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If a clearance is provided at the engraved portion of the die to prevent resin leakage, then resin leakage is prevented, but the metal base plate deforms due to pressure during molding

Engineering Contradiction:

Improvedimensional toleranceVSAvoidmetal base plate deformation

Core Design Contradiction:

Manufacturing precisionVSShape

Solution Approach 1:

The die is pre-formed with an engraved structure that includes a peripheral portion extending beyond the projections. This preliminary structural preparation prevents resin leakage and eliminates the need for clearance gaps, thereby preventing metal base plate deformation and insulating layer cracks during the transfer molding process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The engraved peripheral portion of the die acts as an intermediary structure between the resin and the projections. It controls resin flow and prevents direct pressure concentration on the projections, thereby preventing metal base plate deformation and insulating layer damage during molding

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively suppresses the occurrence of cracks in the insulating layer, improving the electrical reliability and heat dissipation properties of the semiconductor device while allowing for higher resin molding pressures, thus enhancing overall device performance.

Implementation Method 1

when a semiconductor device including a metal base plate having projections and depressions on its one surface is resin-molded by transfer molding, a die needs to have an engraved structure for protecting the projections and depressions without causing resin leakage to the projections and depressions

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 2

a fin base including heat dissipation fins is screwed and joined to the metal substrate with an insulative silicone-based resin material such as grease interposed therebetween, for example

Methodology Applied

Scientific EffectHeat dissipation: Conduction (thermal)

Implementation Method 3

to increase a heat dissipation area to improve the heat dissipation

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS10529643B2Semiconductor device and method of manufacturing the same

Publication Date: 2020.01.07 MITSUBISHI ELECTRIC CORP

AI summary

A semiconductor device that reduces the deformation of a metal base due to pressure during transfer molding, to thereby suppress the occurrence of cracks in an insulating layer to achieve high electrical reliability. The semiconductor device includes: a metal member provided, on its lower surface, with a projection and a depression, and a projecting peripheral portion surrounding the projection and the depression and having a height greater than or equal to a height of the projection of the projection and the depression; an insulating layer formed on an upper surface of the metal member; a metal layer formed on an upper surface of the insulating layer; a semiconductor element joined to an upper surface of the metal layer; and a sealing resin to seal the semiconductor element, the metal layer, the insulating layer and the metal member.