RC-IGBT Electrode Thickness Layout for Precise Light Ion Implantation

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Solution Overview

Problem

Existing semiconductor technologies face challenges in achieving high-precision alignment of metal masks for light ion implantation in RC-IGBTs, leading to misalignment issues that affect the carrier lifetime and electrical characteristics of both the IGBT and diode components, compromising the performance and reliability of the device.

Innovation Solution

The implementation of a metal mask with varying thicknesses for the metal electrodes over the IGBT and diode areas, combined with a method of ion implantation using a resist and electroplating, ensures precise confinement of light ion implantation to the diode area, thereby maintaining the carrier lifetime and electrical characteristics of the IGBT.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a separate metal mask is employed for light ion implantation, then the implantation area can be limited, but high-accuracy alignment between the metal mask and the wafer cannot be achieved

Engineering Contradiction:
Improvealignment precisionVSAvoidmask alignment complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines the metal electrode structure with the metal mask function into a single integrated component. The metal electrode serves dual purposes: as an electrical contact and as the masking structure for ion implantation, eliminating the need for separate mask alignment operations and achieving high precision through the electrode's inherent positional accuracy

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The metal electrode is designed to perform multiple functions simultaneously: it provides electrical connection, serves as the masking structure for ion implantation, and defines the implantation area boundaries. This multi-functionality eliminates the need for separate dedicated mask components and their associated alignment procedures

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Manufacturing precision

If a thick resist is used for area-limited implantation, then the implantation area can be confined, but the resist needs to be extremely thick which complicates the process

Engineering Contradiction:
Improveimplantation area confinementVSAvoidresist thickness requirement
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical resist mask system with an electroplated metal mask system. Instead of relying on thick organic resist layers to block ions, the solution uses electroplated metal structures that provide superior masking capability with much reduced thickness requirements and process complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the material parameter from organic resist to electroplated metal, fundamentally altering the masking mechanism. The electroplated metal provides adequate masking thickness with significantly reduced dimensional requirements compared to thick resist, simplifying the overall process

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the metal electrode thickness is uniform for both IGBT and diode sections, then the manufacturing process is simplified, but the carrier lifetime and electrical characteristics cannot be optimized for both components

Engineering Contradiction:
Improveelectrode thickness uniformityVSAvoidelectrical characteristics optimization
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies different thicknesses of the same metal electrode material to different functional areas: a first thickness over the IGBT section and a second thickness over the diode section. This local differentiation allows optimization of carrier lifetime and electrical characteristics for each component type while maintaining a unified manufacturing approach

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The metal electrode is segmented into distinct thickness regions corresponding to different device sections. The electrode structure is divided into multiple thickness zones that can be independently optimized for the specific electrical characteristics required by each underlying semiconductor component

Inventive Principle:
Principle #1Segmentation

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 minimizes alignment errors, enhances the reverse recovery characteristics of the diode, improves the robustness and efficiency of the RC-IGBT, and allows for a more compact and thermally efficient semiconductor chip design.

Implementation Method 1

method of ion implementation in a semiconductor device, especially implementation of light ion particles

Methodology Applied
Scientific EffectIon implantation: Ion Implantation

Implementation Method 2

the metal electrode comprises at least one thin metal electrode section and at least one thick metal electrode section... ensures precise confinement of light ion implantation to the diode area

Methodology Applied
Scientific EffectDifferential ion penetration through varying metal thickness:

Implementation Method 3

depositing a metal, preferably a Copper, preferably by means of electroplating, on areas not covered by the resist

Methodology Applied
Scientific EffectElectroplating: Electroplating

Data Source

PatentEP4672340A1Semiconductor device and method of ion implementation in a semiconductor device
Publication Date: 2025.12.31 NEXPERIA BV
  • EP4672340A1 patent drawingFigure 1~2
  • EP4672340A1 patent drawingFigure 3
  • EP4672340A1 patent drawingFigure 4~5

AI summary

The present disclosure relates to a semiconductor device, such as a Reverse Conducting Insulated Gate Bipolar Transistor, RC-IGBT, and method of ion implementation in a semiconductor device, especially implementation of light ion particles. A semiconductor device is proposed, comprising a semiconductor structure layer and a metal electrode (21) on at least one surface of the semiconductor layer, wherein the metal electrode (21) comprise at least one thin metal electrode section (21a) and at least one thick metal electrode section (21b). Preferably the at least one thin metal electrode section (21a) has a thickness of 4-7 µm and the at least one thick metal electrode section (21b) has a thickness of 9-14 µm.