Laser-Cut Microstructures With Sacrificial Bridging for Heat Control

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Solution Overview

Problem

Existing methods for forming microprobes and microscale or millimeter-scale structures using laser cutting face challenges such as movement and differential heating issues due to tethering, and the need for improved methods that incorporate both laser-cut features and deposited materials, especially for non-electrodepositable materials like tungsten and molybdenum.

Innovation Solution

A method involving the use of a sacrificial bridging material attached to the backside of a sheet of structural material, where a laser beam cuts through the sheet but not the bridging material, allowing for improved material properties and structural integrity, and subsequent removal of the bridging material to separate the structures, while also allowing for the use of deposited materials with different properties for enhanced conductivity and bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If tethering methods are used to attach parts to the foil during laser cutting, then the parts can be held in position, but movement and differential heating issues occur

Engineering Contradiction:

Improveposition stabilityVSAvoidheating uniformity

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

A sacrificial bridging material is introduced as an intermediary between the sheet material and the base. This bridging material absorbs the laser energy and prevents direct heating of the sheet material, eliminating differential heating issues while maintaining position stability during the cutting process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The laser parameters are adjusted to cut through the sheet material without completely penetrating the bridging material. By controlling the laser energy distribution and cutting depth, the sheet material is severed while the bridging material remains intact to prevent movement during cutting.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If the laser beam cuts completely through the sheet material, then the structures are separated, but movement issues occur during cutting

Engineering Contradiction:

Improveseparation efficiencyVSAvoidposition stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The sacrificial bridging material serves as a mediator that maintains structural integrity during the cutting process. It holds the sheet material in place on the base while allowing the laser to completely cut through the sheet material without causing movement.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If traditional laser cutting methods are used, then cutting speed is maintained, but material properties deteriorate due to excessive heating

Engineering Contradiction:

Improvecutting speedVSAvoidmaterial property quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The sacrificial bridging material acts as a heat barrier that absorbs excess laser energy. This allows the laser to cut through the sheet material at high speed without transferring excessive heat to the sheet material, preserving its mechanical and electrical properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The laser energy that would otherwise cause harmful overheating of the sheet material is redirected to heat and consume the sacrificial bridging material instead. This converts the harmful thermal effect into a beneficial process where the bridging material is selectively removed while protecting the sheet material.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 formation of microprobes with improved material properties, enhanced conductivity, and better thermal management, addressing the challenges of movement and heating issues during laser cutting, and allowing for the integration of non-electrodepositable materials, resulting in more reliable and accurate microstructure fabrication.

Implementation Method 1

using a laser beam to cut completely through the sheet from the front side to the back side

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

the laser beam cuts through the sheet but not the bridging material

Methodology Applied

Scientific EffectLaser energy absorption: Absorption (EM radiation)

Data Source

PatentUS11999016B2Methods of forming parts using laser machining

Publication Date: 2024.06.04 MICROFABRICA INC

AI summary

Embodiments are directed to the formation micro-scale or millimeter scale structures or methods of making such structures wherein the structures are formed from at least one sheet structural material and may include additional sheet structural materials or deposited structural materials wherein all or a portion of the patterning of the structural materials occurs via laser cutting. In some embodiments, selective deposition is used to provide a portion of the patterning. In some embodiments the structural material or structural materials are bounded from below by a sacrificial bridging material (e.g. a metal) and possibly from above by a sacrificial capping material (e.g. a metal).