Symmetric Metallization on Thin Semiconductor Layers

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Solution Overview

Problem

The handling and processing of thin semiconductor substrates in power semiconductor devices become complicated due to the need for reducing the distance between the front and rear sides, leading to challenges in metallization and dicing processes, which affect the mechanical stability and reliability of the devices.

Innovation Solution

A semiconductor device with a thickness of at most 50 μm featuring symmetric copper metallization structures on opposite sides, where the total thickness deviation from the semiconductor layer is no more than 20%, and the difference between the two metallization thicknesses is also within 20% of the total, enhancing mechanical stability and reducing thermo-mechanical stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thickness of the semiconductor die is decreased to reduce the distance between the front side and the rear side, then the on-state or forward resistance is reduced, but the handling and processing of the thin semiconductor substrate becomes more complicated

Engineering Contradiction:

Improveon-state resistanceVSAvoidhandling and processing

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

A carrier substrate is attached to the thin semiconductor die before processing to provide mechanical support during subsequent manufacturing steps. This preliminary action prevents handling complications while maintaining the thin die structure for low resistance

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The carrier substrate acts as an intermediary element that supports the thin semiconductor die during processing and dicing operations, enabling handling of ultra-thin structures without direct manipulation of the fragile die itself

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the thickness of the semiconductor die is decreased to reduce the distance between the front side and the rear side, then the on-state or forward resistance is reduced, but the dicing process becomes more complicated

Engineering Contradiction:

Improveon-state resistanceVSAvoiddicing process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The carrier substrate is attached to the thin semiconductor die before dicing to provide mechanical support during the cutting process, preventing complications associated with handling and processing ultra-thin substrates during dicing operations

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the thickness of the semiconductor die is decreased, then the distance between the front side and the rear side is reduced, but the mechanical stability of the device deteriorates

Engineering Contradiction:

Improveelectrical performanceVSAvoidmechanical stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The carrier substrate provides counterbalancing mechanical support to the thin semiconductor die, compensating for the loss of mechanical stability that results from reducing the die thickness to achieve lower resistance

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The carrier substrate is attached to the thin semiconductor die before processing to provide mechanical support during subsequent manufacturing steps, preventing handling complications while maintaining the thin die structure for low resistance

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11552016B2Semiconductor device with metallization structure on opposite sides of a semiconductor portion

Publication Date: 2023.01.10 INFINEON TECHNOLOGIES AG

AI summary

A semiconductor device includes a semiconductor layer with a thickness of at most 50 μm. A first metallization structure is disposed on a first surface of the semiconductor layer. The first metallization structure includes a first copper region with a first thickness. A second metallization structure is disposed on a second surface of the semiconductor layer opposite to the first surface. The second metallization structure includes a second copper region with a second thickness.