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5.11 Tactile Probing Methods

Profile

The working group focuses on tactile surface measurements and the measurement of small forces. It develops

  • Reference surface measuring devices with tactile sensors, in particular a measuring device for surface measurements in structures with a large aspect ratio (gas and injection nozzles)
  • New tactile sensors for fast, precise, non-destructive surface measurements
  • Standards and measuring methods for the probing force of probe devices, nanoindenters and scanning force microscopes
  • Measuring and evaluation methods for the determination of the radius and the shape of probe tips, indenters and microradiene standards
  • Construction and commissioning of a force measuring device for force measurement in the nano- and sub-nanonewton range.

 

 

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Research/Development

Innovative tactile sensors

  • Piezoresistive Si micro tactile sensors for fast roughness measurements in nozzles and holes with diameters of less than 100 μm (Profilscanner for structures with high aspect ratio) [1]
  • Microelectro-mechanical systems (MEMS) with small deflections and forces in the nanometer range can be measured [2]. Areas of application: fast surface measurement [3], near-surface measurement of E-modul and hardness [4] and calibration of stiffness of AFM cantilevers [5]
  • Traced back and air supported tactile measurement sensor system(Lupo), which allows contact forces in the range of 50 μN to 700 μN (tactile reference measuring device HRTS [6]).
    In the case of soft materials to determ geometric quantities using tactile methods, special attention must be paid to the probe tip shape and the tactile forces in connection with the material properties [7], [8]. 

 

Reference standard for the calibration of the probing force, the tip radius and the z-measuring axis

  • Si-meander reference spring sensors [9], [10] for calibrating the probing force of coordinate measuring devices, nanoindenters and AFM
  • MEMS double-spring sensors for the calibration of the probing force and deflection of stylus instruments, nanoindenters and AFM [11]
  • Probe tip test standard for the calibration of the radius and the 2D shape of diamond probe tips of conventional stylus instruments and of special silicon probe tips (Initiates file downloadFlyer_Stylus tip characterizer_PTB_2017) [12]
  • Diamond-turned groove standards for optical and tactile surface measuring instruments
  • Groove standard up to 5 mm depth with optical surface quality
  • Roughened groove standards for optical measuring instruments
  • Periodical groove standards for special applications

 

Nanoindentation technology with MEMS sensors

 

Probe tip and indenter radii and shape measurement

  • Method for determining the radius and shape of spherical probe tips (confocal microscopy, reference spheres, grid structures, rectangle grooves, sharp-edged diamond edges, probe tip test, 3D electron microscopy, metrological AFM, reference materials)
  • Measurement methods and algorithms for the determination of the contact surface (surface function) of indenters
  • Calibration procedures for micro-radii standards

 

Nanoforce

  • Design, commissioning and operation of the nanoforce measuring device (NKNM) [13]. The NKNM is at the same time a force sensor and a force actuator traced back to the SI system. It is possible to measure forces ≤ 10 μN with 0.1 pN resolution and a relative uncertainty of 10-3 at 1 nN [14].
        Targets are:
        Force measuring range (Fm): 0.1 pN ≤ Fm <10 μN
        Affected uncertainty: 10-3 at 1 nN
        Stiffness range (k): 10-6 N / m - 10 N / m
        Affected uncertainty: 10-3 at k = 10-3 N / m
        Most important force range: 1 pN - 100 nN
  • DFG project "Investigation of the light-induced attraction between two metal bodies with sub-wavelength distance" [15], [16]

 

Opens internal link in current windowReferences  [1] - [16]

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Services

The working group calibrated:


• Radial normals with R ≤ 20 μm
• Probing force standard for stylus instruments
• Force-displacement standard for martensity hardeners
• Cantilever and reference cantilever for scanning force microscopes
• Depth setting standard for measuring ranges from 10 μm to 5 mm
• Micro- and nanoforce sensors
• Indenter for hardness measurements

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Information


Devices and installations


Reference profile methode measurment device (HRTS)

 

 

Short description

 

Principle

 

 

 

 

 

expanded uncertainty (k = 2)

 

Range

HRTS

 

Air guided stylus with variable contact force (100 µN – 700 µN) and inter­fero­metrical

deflection measurement

 

6 nm (2D)

33 nm (3D)

105 nm (Radius)

50 x 50 mm² x
240 µm

Profilscanner

 

Short description

 

Principle

 

 

 

 

 

extended uncertainty
(k = 2)

 

Range

Profilscanner

 

Piezoresistive Si-Micro-stylus with controlled contact force (Fmin = 1 µN) and interferometrical positions measurement

 

10 nm (3D)

 

 

800 x 800 x 250 µm³

Micro force measurement device



Short description

 

Principle

 

 

 

extended uncertainty
(k = 2)

Range

MKME

 

Stiffness measurement device with compensation scale and nano positioning

 

4 % (Stiffness)

3,5 % (Deflection)

3 % (Force)

Maximum: 500 mN, 90 µm

Minimum: 50 nN, 50 nm

Cantilever stiffness measurement device

Short description

 

Principle

 

extended uncertainty
(k = 2)

 

Range

kMEMS

 

MEMS-reference spring-actor

 

5 % (Stiffness)

 

 

0,01 N/m < Stiffness< 300 N/m

Interferometer mounting for characterization of translation stages


Short description

 

Principle

 

extended uncertainty
(k = 2)

 

Resulution

 

Range

Downs-Interferometer

 

Jamin-Interferometer

 

 

 

 

 

12,5 pm

 

10 µm

Profiler Tencor P17


 

Short description

 

Principle

 

 

 

 

extended uncertainty
(k = 2)

 

Range

Tencor P17

 

Profiler with variable contact force (5-500 µN) und capacitive deflection measurement

(22 + d in mm ) nm (z)

 

 

 

 

100 x 100 x 1 mm³

Surface measurement device Mahr LD120

 

Short description

Principle

 

 

 

 

extended uncertaity
(k = 2)

Range

Mahr LD120

Profiler with variable contact force (0,5 – 5 mN) and interference-optical deflection measurement

(22 + d in mm) nm (z)

 

 

120 x50 x 12 mm3

Nanoindenter Hysitron TI950


Short description

 

Principle

 

 

extended uncertainty
(k = 2)

 

 

Range

TI950

 

Penetration


 

 

2 % (Force)

2 % (depth of penetration)

2 % (Stiffness)

F: 1 µN…10 mN

White light interferometer TMS 300



Short description

 

Principle

 

extended uncertainty
(k = 2)

 

Range

TMS 300

 

White light interferometer

 

10 nm

 

 

 

13000 x 10000 x 500 µm³

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