Groove-Defined Substrate Separation for MEMS Sensor Fabrication

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Solution Overview

Problem

MEMS pressure sensors face challenges in device separation due to difficulties in etching material penetration, leading to structural layer damage and decreased yield.

Innovation Solution

A method involving forming a groove on a first substrate, attaching a second substrate with a silicon active layer, etching to leave only the silicon active layer, forming a thin film structure, and separating the second substrate with the thin film structure from the first substrate, using alkaline hydroxide solutions and hydrogen fluoride compounds for etching, and bonding techniques like melting or hybrid bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sacrificial layer is used to form the structural layer above it, then the device structure can be built, but etching material cannot penetrate into the lower portion and the structural layer may be damaged

Engineering Contradiction:

Improvestructural layer integrityVSAvoidetching material penetration

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the substrate into multiple sections by forming grooves that partition the sacrificial layer into separate regions. This segmentation allows etching material to access and remove the sacrificial layer from multiple locations, solving the penetration problem while maintaining structural layer integrity through controlled separation paths.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary groove formation in the substrate before depositing the structural layer. This preliminary action creates predetermined pathways that guide etching material flow in subsequent steps, ensuring complete sacrificial layer removal without requiring the etching material to penetrate through already-formed structural layers.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the structural layer is formed above the sacrificial layer, then the device structure is complete, but device separation becomes difficult and yield decreases

Engineering Contradiction:

Improvedevice separation efficiencyVSAvoiddevice yield

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

By forming grooves that segment the sacrificial layer into isolated regions, the patent creates natural separation planes. After structural layer formation, these pre-formed grooves allow easy separation of individual devices or substrate sections, dramatically improving device separation efficiency and yield without compromising structural integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The grooves act as intermediary spaces between structural layers and sacrificial regions. These intermediate channels facilitate controlled material removal and enable clean separation interfaces, allowing the structural layer to be successfully separated from the substrate while maintaining high device yield.

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 method enhances the yield of semiconductor device fabrication by facilitating easy separation of the second substrate while maintaining the structural integrity of the silicon active layer, improving the waterproof and ventilation performance of the gas sensor.

Implementation Method 1

forming a groove by etching one side surface of a first substrate

Methodology Applied

Scientific EffectChemical etching:

Implementation Method 2

etching the second substrate so as to leave substantially only the silicon active layer

Methodology Applied

Scientific EffectChemical etching:

Implementation Method 3

bonding techniques like melting or hybrid bonding

Methodology Applied

Scientific EffectMelting bonding:

Data Source

PatentUS11667524B2Method for fabricating semiconductor device

Publication Date: 2023.06.06 HYUNDAI KEFICO CORP

AI summary

Disclose is a method for fabricating a semiconductor device. The method includes: forming a groove such as by etching one side surface of a first substrate; attaching a second substrate including a silicon layer on the etched surface of the first substrate formed with the hollow groove; etching the second substrate so as to leave substantially only the silicon layer; forming a thin film structure on the surface of silicon layers of the second substrate; and separating the second substrate formed with the thin film structure from the first substrate. For example, the groove structure may be formed in the lower portion of the device in the process of fabricating the semiconductor device to facilitate the final device separation.