Micro-Device Etch Holes for Faster, Damage-Reduced Release

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing micro-device transfer methods face challenges with slow etch rates and anisotropic etching in crystalline source wafers, leading to etching damage and reduced manufacturing throughput, compromising the integrity of micro-devices and transfer structures.

Innovation Solution

The introduction of micro-device structures with etch holes that expose sacrificial portions through the micro-device, allowing for faster and more controlled release by etching, using anisotropically etchable crystalline structures like silicon {100}, with etch holes oriented to minimize damage and facilitate efficient transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional etching methods are used on crystalline source wafers, then the sacrificial portion can be etched, but the etch rate is slow and the micro-device is only partially undercut due to anisotropic etching

Engineering Contradiction:

Improveetch rateVSAvoidmicro-device integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces etch holes that segment the micro-device structure, allowing etchant to access the sacrificial portion from multiple locations simultaneously. This segmentation enables parallel etching paths, dramatically increasing the effective etch rate while maintaining complete undercutting of the sacrificial portion despite the anisotropic nature of crystalline etching.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent adds a vertical dimension to the etching process by creating etch holes through the micro-device from the top surface down to the sacrificial portion. This transforms the etching from a purely lateral process to a three-dimensional process, allowing etchant to reach the sacrificial material directly and enable complete release without prolonged exposure that would damage the micro-device.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If the etch takes a substantial amount of time to complete, then the sacrificial portion can be fully removed, but the integrity of the micro-device, tether, and anchor portion is compromised

Engineering Contradiction:

Improverelease timeVSAvoidetching damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent performs preliminary action by pre-forming etch holes through the micro-device before the etching process begins. These pre-formed holes provide direct pathways for etchant to reach the sacrificial portion, eliminating the need for slow lateral etching and enabling rapid, controlled removal of the sacrificial material without exposing the micro-device to prolonged etching conditions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The etch holes act as intermediaries that facilitate controlled etchant delivery to the sacrificial portion. They allow the etching process to proceed rapidly through defined pathways while protecting the surrounding micro-device structures from harmful etchant exposure, effectively mediating between the need for fast etching and the need to preserve structural integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If slow etch rates are used, then manufacturing throughput is reduced, but the selectivity amongst materials is maintained

Engineering Contradiction:

Improvemanufacturing throughputVSAvoidetch selectivity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

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

Enables rapid and damage-reduced release of micro-devices from source wafers, enhancing manufacturing efficiency and reducing etching damage to micro-devices and transfer structures.

Implementation Method 1

Crystalline source wafers can etch anisotropically so that the etch proceeds more rapidly in one direction than in another direction with respect to the crystal planes in the source wafer

Methodology Applied

Scientific EffectAnisotropic etching:

Data Source

PatentUS12398031B2Micro-device structures with etch holes

Publication Date: 2025.08.26 X CELEPRINT LIMITED

AI summary

A micro-device structure comprises a source substrate having a sacrificial layer comprising a sacrificial portion adjacent to an anchor portion, a micro-device disposed completely over the sacrificial portion, the micro-device having a top side opposite the sacrificial portion and a bottom side adjacent to the sacrificial portion and comprising an etch hole that extends through the micro-device from the top side to the bottom side, and a tether that physically connects the micro-device to the anchor portion. A micro-device structure comprises a micro-device disposed on a target substrate. Micro-devices can be any one or more of an antenna, a micro-heater, a power device, a MEMs device, and a micro-fluidic reservoir.