MEMS Probe Testing System Multi-Axis Alignment

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Solution Overview

Problem

Current MEMS testing systems fail to simultaneously measure mechanical and electrical properties effectively due to limitations in probe-based methods, such as restricted directional testing, inability to measure stiffness and force directly, and lack of combined electrical and mechanical data acquisition, leading to measurement errors and inefficiencies in validating designs and quality control.

Innovation Solution

A probe-based MEMS testing system that combines micromechanical and electrical testing using motorized, multi-axis micropositioning units with integrated microforce and electrical probes, enabling precise alignment, direct measurement of mechanical properties, and simultaneous observation of the MEMS structure, allowing for both vertical and horizontal testing on structured and non-flat chips/wafers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If optical methods (laser Doppler vibrometer) are used for MEMS testing, then fast non-contact deflection measurement over a large frequency range is achieved, but direct measurement of stiffness, force, linearity, hysteresis, and yield strength is not possible

Engineering Contradiction:
Improvemeasurement speedVSAvoiddirect measurement capability
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent combines optical deflection measurement with probe-based mechanical force measurement into a single integrated testing system. The mechanical probe directly contacts the MEMS structure to apply force and measure mechanical properties (stiffness, force, linearity, hysteresis, yield strength) while the optical system simultaneously measures deflection, enabling both direct mechanical measurement and fast non-contact deflection measurement to occur together

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a mechanical probe as an intermediary between the testing system and the MEMS structure. This probe serves as a mediator that can directly measure mechanical properties while the optical system acts as another intermediary for non-contact deflection measurement, allowing both measurement methods to complement each other without interference

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If conventional MEMS testing systems are used, then testing can be performed, but combined measurement of both mechanical properties and electrical signals cannot be offered

Engineering Contradiction:
Improvetesting capabilityVSAvoidelectrical signal measurement
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent creates a universal testing system that can perform multiple functions: mechanical property measurement through probe-based testing, electrical signal measurement through integrated probes, and optical deflection measurement. This multi-functional system eliminates the need for separate testing equipment and enables simultaneous acquisition of mechanical and electrical data from MEMS devices

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges mechanical testing capabilities with electrical testing capabilities into a single integrated system. The mechanical probe and electrical probes are combined in one testing platform, allowing simultaneous measurement of mechanical properties (force, stiffness, deflection) and electrical signals (voltage, current, resistance, capacitance, charge) without requiring separate testing equipment

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If atomic force microscopes and nanoindentors are used, then mechanical properties can be measured, but the systems are limited to vertical measurements only and cannot be used for in-plane deflection/force measurement

Engineering Contradiction:
Improvemechanical property measurementVSAvoidmeasurement direction
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent extends measurement capabilities from single-axis (vertical) to multi-axis by incorporating a multi-axis micropositioning unit with at least two degrees of freedom. This allows the mechanical probe to apply forces and measure deflections in both vertical and in-plane directions, enabling comprehensive mechanical characterization of MEMS structures in multiple dimensions simultaneously

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

4Adaptability or versatility

If a conductive tip is used for electrical probing, then electrical probing is possible, but only with the microforce sensor rather than with additional electrical probes

Engineering Contradiction:
Improveelectrical probing capabilityVSAvoidelectrical signal measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent separates the mechanical probing function from the electrical probing function by using distinct probes: a mechanical probe for force and stiffness measurement, and separate electrical probes for voltage, current, resistance, capacitance, and charge measurement. This segmentation allows each probe to be optimized for its specific function while working together in an integrated testing system

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2896594B1System for the combined, probe-based mechanical and electrical testing of MEMS
Publication Date: 2018.04.18 FEMTOTOOLS
  • EP2896594B1 patent drawingFigure 1
  • EP2896594B1 patent drawingFigure 2
  • EP2896594B1 patent drawingFigure 3

AI summary

A system (100) for testing MEMS-structures comprises - a microforce sensor (1); - two or more multi-axis micropositioning units (2); - at least one or electrical probe (4); - a sample holder (5) on which a MEMS-structure (6) is mounted. At least one of said multi-axis micropositioning units (2) is motorized and at least one additional micropositioning unit (2) is equipped with at least one electrical probe (4) to apply electrical signals or to measure electrical signals at one or multiple locations on the MEMS structure (6). The system with the before mentioned components allows a combined electrical and probe-based mechanical testing of MEMS-structures (6).