SPM Probe Tip Aspect Ratio via Self-Aligned Plasma Etch

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Solution Overview

Problem

Current SPM probe tips have a low aspect ratio, which limits their resolution and effectiveness in scanning sub-10nm technology nodes, and existing methods for increasing the aspect ratio are technically complex.

Innovation Solution

A method is developed to produce probe tips with increased aspect ratio by creating smaller nano-sized tip portions on a larger micrometer-sized tip body using a self-aligned plasma etch procedure with a mask layer of irregular thickness comprising seed particles and spontaneously formed compounds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional tip fabrication methods are used, then the manufacturing process is simple, but the aspect ratio of the tip is too low for sub-10nm technology nodes

Engineering Contradiction:
Improveaspect ratioVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The tip fabrication process is segmented into distinct stages: forming a mold cavity in the substrate, depositing seed particles, growing the tip body, and performing selective plasma etching to create nano-sized tip portions. This segmentation allows each stage to be optimized independently, achieving high aspect ratios without proportionally increasing overall manufacturing complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Seed particles are deposited in the mold cavity before tip body growth, and a mask layer is formed on the tip body surface before the plasma etching step. These preliminary actions prepare the structure in advance, enabling the subsequent plasma etching to selectively create high aspect ratio tip portions without requiring complex real-time control during etching

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the tip aspect ratio is increased to resolve sub-10nm features, then the resolution improves, but the manufacturing complexity increases significantly

Engineering Contradiction:
Improvesurface feature resolutionVSAvoidmicromachining complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The plasma etching process is self-aligned, using the mask layer that is already present on the tip body surface. The etching automatically creates tip portions with high aspect ratios without requiring additional alignment steps or complex micromachining equipment. The process uses the existing structure to guide the formation of the high-resolution tip features

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The plasma etching parameters (power, gas composition, pressure, duration) are optimized to achieve selective removal of material at controlled rates. By adjusting these parameters, the process creates tip portions with aspect ratios suitable for sub-10nm imaging without requiring mechanically complex micromachining operations

Inventive Principle:
Principle #35Parameter changes

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

The method achieves a significant increase in the aspect ratio of the probe tip, enhancing its resolution and capability to scan nano-scale surface features without requiring complex micromachining techniques.

Implementation Method 1

subjecting the probe tip body to a plasma etch procedure, wherein the mask layer acts as an etch mask for the etching of the probe material

Methodology Applied
Scientific EffectPlasma etching: Plasma

Data Source

PatentEP3702792B1A method for producing a probe suitable for scanning probe microscopy
Publication Date: 2025.02.12 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP3702792B1 patent drawingFigure 1a~1b
  • EP3702792B1 patent drawingFigure 1c~1d
  • EP3702792B1 patent drawingFigure 1e~2c

AI summary

According to the invention, one or more smaller tip portions (15) are produced on the larger tip body (10) of a probe suitable for SPM, after the production of the probe tip body as such. The probe tip body may be produced according to any technique known in the art, for example by a molding technique. The creation of the smaller tip portions (15) is realized by a self-aligned plasma etch procedure, using a mask layer on the outer surface of the probe tip body (10). The mask layer may comprise nano-sized particles (3) and/or compounds (12) formed spontaneously on the outer surface of the tip body or of the mold, such as oxides or oxycarbides. The nano-sized particles (3) may be seed particles deposited in the mold (2) prior to the deposition of the probe material therein, and/or particles produced during the etch process itself, such as particles sputtered from the cantilever or from the reaction chamber in which the etch process is performed. Alternatively or in addition, masking particles may be deliberately deposited on the tip body prior to the etch procedure.