Epitaxial Wafer Terrace Processing for Crack Prevention

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Solution Overview

Problem

Despite existing methods to prevent cracks in epitaxial wafers, cracks still occur near the outer peripheral regions due to crown generation, posing risks of delamination and contamination in semiconductor device manufacturing.

Innovation Solution

Applying terrace processing, such as grinding, to the outer peripheral portion of silicon-based substrates before epitaxial growth to create a flat surface that suppresses stress and crack formation, and optionally polishing to a mirror or quasi-mirror finish to prevent particle generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chamfering or roughening is applied to the outer peripheral portion of the silicon-based substrate, then crack formation is reduced, but crown generation and stress imbalance still occur affecting manufacturing precision

Engineering Contradiction:

Improvecrack preventionVSAvoidepitaxial layer uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary planarization processing to the outer peripheral portion of the silicon-based substrate before epitaxial growth. This advance preparation creates a flat surface that prevents crown generation during epitaxial growth, while simultaneously preventing crack formation. The planarization is performed at a depth of 1-10 μm to achieve both crack prevention and uniform epitaxial layer formation without stress imbalance.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies different surface treatments to different regions of the substrate. The outer peripheral portion undergoes planarization processing to create a flat surface, while the central portion maintains its original characteristics. This localized treatment ensures that the epitaxial growth layer forms uniformly across the entire substrate surface, preventing both cracks and crown generation.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If the epitaxial growth layer thickness is optimized for the central portion, then device performance is improved, but crown generation causes stress imbalance and crack formation at the outer peripheral portion

Engineering Contradiction:

Improveepitaxial layer thickness controlVSAvoidcrack-free structure

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent performs planarization processing on the outer peripheral portion before epitaxial growth to eliminate the geometric irregularities that cause crown generation. This preliminary action ensures that the epitaxial growth layer forms with uniform thickness across the entire substrate, including the outer peripheral portion, preventing stress imbalance and crack formation while maintaining optimal thickness for device performance.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the surface geometry parameter of the outer peripheral portion through planarization, transforming it from a chamfered or roughened surface to a flat surface. This parameter change allows the epitaxial growth layer to form uniformly without crown generation, maintaining both optimal thickness control and crack-free structure.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If existing crack prevention methods are applied, then some crack formation is reduced, but residual cracks remain within several millimeters from the outer peripheral portion causing delamination risk

Engineering Contradiction:

Improvecrack reductionVSAvoiddelamination and contamination risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies planarization processing to the outer peripheral portion before epitaxial growth to eliminate the root cause of crack formation. This preliminary surface preparation creates a flat substrate that prevents both crown generation and crack formation during epitaxial growth, eliminating delamination risks entirely rather than merely reducing crack formation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent divides the substrate surface treatment into distinct regions: the outer peripheral portion receives planarization processing while the central portion maintains its original characteristics. This segmentation allows targeted prevention of cracks and crown generation at the outer peripheral portion without affecting the optimal epitaxial growth conditions in the central region.

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 method ensures the production of crack-free epitaxial wafers, preventing delamination and contamination in device manufacturing processes by relaxing stress and reducing particle-related failures.

Implementation Method 1

epitaxially growing a semiconductor layer on the silicon-based substrate

Methodology Applied

Scientific EffectEpitaxial growth: Epitaxy

Data Source

PatentUS10319587B2Method of manufacturing epitaxial wafer and silicon-based substrate for epitaxial growth

Publication Date: 2019.06.11 SHIN ETSU HANDOTAI CO LTD

AI summary

A method of manufacturing an epitaxial wafer having an epitaxial layer on a silicon-based substrate, the method of manufacturing the epitaxial wafer including epitaxially growing a semiconductor layer on the silicon-based substrate after applying terrace processing to an outer peripheral portion of the silicon-based substrate. As a result, the method of manufacturing the epitaxial wafer having the epitaxial layer on the silicon-based substrate in which an epitaxial wafer which is completely free from cracks can be obtained, is provided.