Lithium Microbattery Manufacturing via Self-Aligned Etching

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Solution Overview

Problem

The existing methods for producing lithium microbatteries are challenging due to the sensitivity of lithium layers to air and humidity, chemical instability, and the complexity of structuring solid electrolyte layers, which leads to issues with mechanical masking techniques causing contamination and edge effects, and laser ablation methods being slow and dependent on substrate and layer properties.

Innovation Solution

A method involving a stack of layers with a first and second material, a solid electrolyte, and electrodes, where patterns are etched to define covered and uncovered areas, using the second pattern as an etching mask, and a lithium layer is formed by diffusing lithium atoms into the second pattern, avoiding mechanical masks and minimizing exposure to air and humidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If mechanical masking is used to structure the solid electrolyte layer, then the electrolyte layer can be patterned, but particulate contamination and edge effects occur

Engineering Contradiction:
Improveelectrolyte layer patterningVSAvoidparticulate contamination and edge effects
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical masking system with a self-aligned chemical etching system. The solid electrolyte layer is patterned using wet chemical etching through openings in the electrode layers, eliminating mechanical masks that cause particulate contamination and edge effects. This substitution of mechanical patterning with chemical etching resolves the contradiction by achieving precise patterning without the harmful mechanical artifacts.

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

2Object-affected harmful factors

If laser ablation is used to structure the solid electrolyte layer, then mechanical masking issues are avoided, but the production process becomes slow and complex

Engineering Contradiction:
Improveavoidance of mechanical mask contaminationVSAvoidproduction speed
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent employs a self-aligned etching process where the electrode layers automatically serve as etching masks for the solid electrolyte layer. The openings in the electrodes define the pattern areas, and the etching process naturally stops at the electrode layer without requiring additional masking steps or complex laser systems. This self-service approach eliminates the need for separate structuring equipment while maintaining high production speed and avoiding mechanical mask contamination.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If the solid electrolyte layer is exposed to air and humidity during production, then production steps can be simplified, but chemical instability and degradation occur

Engineering Contradiction:
Improveproduction process simplicityVSAvoidelectrolyte chemical stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent implements a continuous vacuum process where all production steps - deposition, patterning, and assembly - are performed in a vacuum environment without exposure to air or humidity. The solid electrolyte layer is deposited and patterned in-situ under vacuum conditions, and the entire process occurs in a sealed vacuum chamber. This inert vacuum environment prevents chemical degradation of the hygroscopic solid electrolyte while maintaining production simplicity through a streamlined single-chamber process.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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 simplifies the production of lithium microbatteries, reduces contamination risks, maintains electrolyte quality, and allows for precise patterning, increasing integration density and electrochemical performance while avoiding mechanical mask-related issues and exposure to aqueous solutions.

Implementation Method 1

a lithium-based layer (16) is formed on the second pattern (M2), the lithium atoms diffusing in the second pattern (M2)

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2833461B1Method of manufacturing a lithium microbattery
Publication Date: 2017.09.13 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2833461B1 patent drawingFigure 1~2
  • EP2833461B1 patent drawingFigure 3~4
  • EP2833461B1 patent drawingFigure 5

AI summary

The manufacturing process for a lithium microbattery is carried out using a stack of layers comprising successively: a first layer (11) of the first material, a second layer (12) of the second material, a solid electrolyte layer (13), and a first electrode (14). The process further includes etching to form a first pattern (M1) of the first material and a second pattern (M2) of the second material, the second pattern defining a covered area (13") and an uncovered area (13') of the electrolyte layer (13). The uncovered area (13') is then etched, using the second pattern (M2) as the etching mask. After etching the first pattern (M1), a lithium-based layer is formed on the second pattern (M2), the lithium-based layer and the second pattern forming a second lithium-based electrode.