Semiconductor Layer Transfer via Confinement Structure

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Solution Overview

Problem

Existing methods for transferring silicon layers in semiconductor substrates often result in defects and roughness, particularly when breaking at an embrittlement zone, which is problematic for manufacturing ultrathin layers like those required for fully-depleted silicon-on-insulator (FD-SOI) substrates.

Innovation Solution

A method involving a donor substrate with a confinement structure comprising a semiconductor material and protective layers, where ions are introduced and concentrated during heat treatment to facilitate a controlled break at the confinement layer, allowing for the transfer of a useful layer with reduced roughness and defect confinement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If breaking is performed at an embrittlement zone to transfer a silicon layer, then the layer can be transferred from donor to receiver substrate, but defects and roughness are induced in the transferred layer

Engineering Contradiction:

Improvesurface roughnessVSAvoiddefect density

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A confinement structure comprising a confinement layer and protective layers is introduced as an intermediary element between the useful layer and the breaking zone. This structure mediates the breaking process by localizing it to the confinement layer while protecting the useful layer from direct damage, thereby reducing defects and roughness in the transferred layer

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The substrate structure is segmented into distinct functional zones: the useful layer, the confinement layer, and protective layers. This segmentation allows the breaking process to occur in a dedicated confinement layer rather than directly affecting the useful layer, thus improving transfer quality

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If a thick silicon layer (200-250 nm) is transferred to compensate for surface-smoothing consumption, then sufficient material remains after smoothing, but the layer thickness is larger than necessary for ultrathin applications

Engineering Contradiction:

Improveultrathin layer precisionVSAvoidsilicon layer thickness

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

Protective layers are applied beforehand to cushion and protect the useful layer during the breaking and transfer process. This allows thinner useful layers to be transferred successfully without excessive material consumption, enabling ultrathin layer manufacturing with reduced thickness

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

This approach enables the transfer of thin semiconductor layers with significantly reduced roughness and facilitates substrate finishing, effectively addressing the defects associated with traditional breaking methods.

Implementation Method 1

subjecting the donor substrate and the receiver substrate to a heat treatment comprising an increase in temperature, during which the confinement layer attracts the ions in order to concentrate them in the confinement layer

Methodology Applied

Scientific EffectIon attraction and concentration: Diffusion

Implementation Method 2

the protective layers being capable of confining in the confinement structure defects that appear following breaking at the confinement layer

Methodology Applied

Scientific EffectDefect confinement: Physical Containment

Implementation Method 3

subjecting the donor substrate and the receiver substrate to a heat treatment comprising an increase in temperature

Methodology Applied

Scientific EffectThermal heating: Heating

Data Source

PatentUS9716029B2Method for transferring a layer of a semiconductor and substrate comprising a confinement structure

Publication Date: 2017.07.25 SOITEC SA

AI summary

A method for transferring a layer of semiconductor by providing a donor substrate that includes a useful layer of a semiconductor material, a confinement structure that includes a confinement layer of a semiconductor material having a chemical composition that is different than that of the useful layer, and two protective layers of semiconductor material that are distinct from the confinement layer with the protective layers being arranged on both sides of the confinement layer; introducing ions into a donor substrate, bonding the donor substrate to a receiver substrate, subjecting the donor and receiver substrates to a heat treatment that provides an increase in temperature during which the confinement layer attracts the ions in order to concentrate them in the confinement layer, and detaching the donor substrate from the receiver substrate by breaking the confinement layer.