Vertical Glass Membranes via Laser-Induced Deep Etching

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Solution Overview

Problem

The production of very thin, reproducible micromechanical glass membranes with vertical bending structures is challenging using conventional planar technologies, leading to inhomogeneity in mechanical properties and susceptibility to external influences, while existing methods for structuring glass membranes often require large substrate areas and are difficult to control.

Innovation Solution

The use of the LIDE process, involving laser-induced deep etching of glass substrates followed by wet-chemical etching, allows for the creation of vertical membranes with controlled thickness and mechanical properties, enabling the production of membranes with high flexibility and breaking strength by forming blind holes that delimit the membrane surfaces, which can be designed to run obliquely to the substrate plane.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional planar technologies are used to produce thin glass membranes, then production can be achieved, but the membranes exhibit inhomogeneity in mechanical properties and are susceptible to external influences

Engineering Contradiction:
Improvemechanical property uniformityVSAvoidsusceptibility to external influences
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent transitions from conventional planar (2D) membrane structures to three-dimensional vertical membrane structures extending into the substrate depth. This dimensional change allows the membrane to be anchored within the substrate rather than lying on the surface, reducing susceptibility to external mechanical influences while achieving homogeneous mechanical properties through controlled laser-induced modification and wet-chemical etching processes.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If vertical bending structures are used to save space, then the footprint is reduced, but the fabrication becomes challenging using planar technologies

Engineering Contradiction:
Improvesubstrate footprintVSAvoidfabrication difficulty
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

The patent replaces conventional mechanical planar fabrication techniques with a laser-based modification process followed by wet-chemical etching. This substitution enables the creation of complex vertical bending structures and three-dimensional membrane configurations that cannot be achieved through traditional planar photolithography and mechanical processing methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention utilizes laser-induced modification to change the physical and chemical parameters of the glass substrate, creating modified regions with altered etch rates. By controlling laser parameters (energy density, pulse duration, scanning speed) and etching conditions, precise control over vertical membrane geometry, thickness, and bending structure characteristics is achieved, simplifying the fabrication of complex three-dimensional structures.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If horizontal membranes are used, then they can be manufactured relatively easily, but they require large substrate area and exhibit high inhomogeneity in mechanical properties

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidsubstrate area requirement
Core Design Contradiction:
Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent converts horizontal in-plane membrane deflection to vertical out-of-plane deflection by creating three-dimensional membrane structures that extend perpendicular to the substrate surface. This dimensional transformation reduces the required substrate area while maintaining manufacturing simplicity through the laser-induced modification process, which can uniformly process large areas and create consistent mechanical properties throughout the vertical structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 reproducible production of thin, flexible, and strong vertical membranes with precise control over mechanical properties, reducing the footprint and susceptibility to external influences, and allowing for the creation of complex micromechanical structures like spring elements and solid-state joints.

Implementation Method 1

exposed from a glass substrate by laser-induced modification of the glass substrate and subsequent wet-chemical etching

Methodology Applied
Scientific EffectLaser-induced deep etching: Laser

Implementation Method 2

laser-induced modification of the glass substrate and subsequent wet-chemical etching

Methodology Applied
Scientific EffectWet-chemical etching:

Data Source

PatentEP4402092B1Monolithic glass membrane, double vertical membrane arrangement, micromechanical spring structure and associated production method
Publication Date: 2024.10.30 LPKF LASER & ELECTRONICS AG
  • EP4402092B1 patent drawingFigure 1~2
  • EP4402092B1 patent drawingFigure 3~4
  • EP4402092B1 patent drawingFigure 5~7

AI summary

In order to expand the application possibilities of micromechanical bending structures 2 in glass, it is proposed to form vertical membranes 1 monolithically in the glass substrate 3 that extend transverse to a substrate plane 5 of a glass substrate 3, by creating blind holes 8 by means of a laser-induced modification of the glass substrate 3 and subsequent wet chemical etching. This makes it possible not only to arrange bending structures 2 inside the body 40 of the glass substrate 3, but also to form spring structures 19 and solid state joints 35 monolithically, in particular in the depth of the glass substrate 3. This also enables novel actuation concepts in glass.