NanoForce -short note - Ilja Hermann October 24,

Transcription

1 NanoForce -short note - Ilja Hermann October 24,

2 System overview Microscope for inspection pre- and pre- and post-test Actuator housing Specimen tray Thermal/Acoustic/ Seismic hood Optional vacuum chuck Coaxial optical lenses and AFM Quantitative property assessment: HIT, EIT, E, E, Y, K IC, σ Rep (ε Rep ), F Crit., topography Electromagnetic actuator (indentation loads between 0.2 un and 45 mn) Three-plate capacitor (indentation depth up to 40 um) Load control Depth- and strain-rate control by S/W feedback control Berkovich tip is included; misc. different indenter geometries optional; easy switch In-line microscope with coaxial turret optics and AFM are standard Automatic multi-specimen handling (magnetic, vacuum, mech. clamp mounting) Internal (3-plate) capacitance sensor housing October 24,

3 System data sheet Basic configuration with imaging options Scratch option October 24,

4 Typcial Nanoindentation test AFM & Optical View (post IMG of surface with 9 indents at different surface locations) Indentations Force-Displacement curves (Dynamic indentations at 9 different surface positions) Cube corner into Si (100) Berkovich into HPFS 1.5 um 1.7mm 1. Test positioning 2. Applying the test method (running indent-loading profile and analysis) 3. Post inspection of tested surface area October 24,

5 How small the testing object can be (NanoForce tip has to hit the spot)? Experiment: AFM 10-times Indent After indent #1 After indent #10 Timeline Target Even after subsequently adding 9 more indents, all tests remain <0.5 um away from target position Video: ftp://tmtftp.bruker-nano.com/tmt/outgoing/nanoforce/nano-dart.m4v => Nanoforce can perform NI experiments on specimen under 1 um lateral size

6 Instrument calibration

7 Hardness and Young s Modulus on SiO2 NanoForce results at different surface positions Typical results for dynamic indentation: Modulus F/S^2 Hardness Force-Displacement curve (corrected raw-data) October 24, 20167

8 Quasi-static Indentation hardness and- modulus on reference materials BK7 BK7 HPFS HPFS Typical Hardness- and Modulus-measurements on homogenous materials used for instrument verification. October 24,

9 Thin film applications

10 Dynamic measurements of thermal-sio2 film on Silicon Strain-rate controlled indentation with Berkovich tip and superimposed 2 nm harmonic excitation 120 Hz on various thickness on Si (100) on substrate: 50 nm 100 nm 300 nm Bulk Si: ~164 GPa Bulk Bulk SiO 2 :~72 GPa October 24,

11 Brittle material characterization October 24,

12 Nano-indentation results Fracture toughness Step 1: Measure Hardness and Young s modulus of the specimen Step 2: Produce a series of indentations at different loads and surface locations Step 3: Image indents to find critical load for fully developed set of lead corner radial cracks Step 4: Calculate Fracture toughness : Cube Corner [1]: Berkovich [2]: Method inputs: E Young s modulus H hardness P test load a, c, l.distances from image [1] D. S. Harding, W. C. Oliver and G. M. Pharr: Mat. Res. Soc. Symp. Proc., 356, 1995, 663. [2] R. Dukino and M.V. Swain, J. Am. Ceram. Soc , 1992, 3299 October 24,

13 Characterization of metallic single crystals October 24,

14 Quasi-static indentation with multiple-partial unloading Modified Berkovich tip on Aluminum (110) single crystal F krit Initial elastic-plastic transition can be observed at ~20uN Perfect elastic partial unloading cycles (no hysteresis) Pop-ins appear associated to the beginning / end of a partial unloading cycle October 24,

15 Dynamic indentation on single crystals: Cube Corner tip on Copper (110) and (111) orientations F krit Cu (110) Cu (111) The (111) orientation appears stiffer than the (110) orientation The (111) orientation exhibits pop-in events at approx. 10 un load October 24,

16 Indentation Creep October 24,

17 Quasi-static indentation with multiple-partial unloading and CREEP Cube corner on Aluminum (110) single crystal OM AFM P max Indentation Creep found to be CIT~6% constant load Most significant contributor to depth-increase during peak-load-hold time are pop-in events (Plastic flow/ dislocation mobility) October 24,

18 (Soft) Polymers October 24,

19 (soft) Polymers Quasi-static indentation on PDMS with cube corner tip ( very sharp on very soft ) EIT=( ) Mpa HIT=( ) Mpa EIT=( ) Mpa HIT=( ) Mpa CIT=(52+-9) % CIT=( ) % Repeatable raw-data due to precise load-control below 10 un Both PDMS-blends clearly distiguished at hand of raw-curves (F(h), h(t)) Resultant YOUNG s modulus is in line with expectations (3.5 Mpa & 2.5 MPa resp. for PeakForce QNM) Indentation creep exceeds 30% October 24,

20 Adhesion October 24,

21 Adhesion Quasi-static indentation on PDMS with 50 um conical tip Nano-Indenter gives insights into new more complex contact physics: Contact model with stiction (DMT) 4 3 P indenter = Er Rd + P 3 Adhesion R=50um R=5 um Obtain quantitative data : DMT modulus, ~1 Mpa Adhesion Energy dissipation Surface deformation R=2.5 um Tip-stiction forces was approach (and pull-off) down to 2.5 um radius October 24,

22 Scratch October 24,

23 Micro-Scratch 5x scratch into AL(110) Length 200 um length, lateral strain rate 0.1 Hz, Conical R=5 um, 50x optical magnification, stitched progressive load mn Repeatability: constant load 10 mn

24 _P130 Constant load Nano-Scratch 300 nm SiO2 on Si with Conical 2.5 um Pairs of constant load scratch series (1, 3, 5, 7, 10) mn, Length 20 um, 10mN; Strain rate 0.1 Hz topography (NanoLens) 1-D profile through scratch series

25 Nano-Scratch 1x progressive load scratch; mn; Length 20 um length, Strain rate 0.1 Hz; Conical R=5 um 25 nm ITO on PET 30 nm SiO 2 on PET

26 Nano-Scratch 2x progressive load scratch; mn; Length 20 um length, Strain rate 0.1 Hz; Conical R=5 um 24 nm brittle film on Si Instrumented scratch data: F crit ~44mN Longitudinal load

27 _P130 Progressive Zig-Zag-Micro-Scratch 300 nm SiO2 on Si with Conical 2.5 um 1x progressive load ZigZag scratch; Length 50 um, 25 cycles, Pitch 1 um, 1-50mN; lateral strain rate 1 Hz Stage Motion Trajectory F crit ~25 mn

28 _P130 Progressive Zig-Zag-Micro-Scratch 300 nm SiO2 on Si with Conical 2.5 um 1x progressive load ZigZag scratch; Length 50 um, 25 cycles, Pitch 1 um, 1-30mN; lateral Strain rate 1 Hz Transversal post-profiling with indenter average profiling loads ca. 2 un Failure event identification by tip-profiling Profiling load stability Cleaned from debris Topography ZigZag-Trajectory Straight Trajectory Critical load determination e.g. by counting integer # of traces ; uncertainty is the scratch length Note: Regular progressive scratch shows no failure while ZigZag scratch promotes same range of load variation

29 _P130 Progressive Zig-Zag-Nano-Scratch 300 nm SiO2 on Si with Conical 2.5 um 1x progressive load ZigZag scratch; Length 10 um, 25 cycles, Pitch 1 um, 1-30mN; Strain rate 1 Hz Error Signal Topography Catastrophic failure of 300 nm coating can be induced via ZigZag scratch when a regular progressive load scratch would not fail the coating system Critical load determination by counting integer # of traces ; uncertainty is the scratch length

30 Other misc. applications October 24,

31 Imaging: AFM topography of a Berkovich tip Direct measurement: Tip radius ~40nm

32 Precision of head mount and Indenter tip mounting NanoForce tip shape options: mod. Berkovich Cube Corner Vickers Conical R=Var Flat Punch R=Var Requires remove/reinstall tip Experiment: Measure remaining pos. accuracy after tip change Cube Corner tip => Berkovich tip Pos error ~7 um and re-calibrate inline offset Berkovich Tip => Conical tip Pos error ~5 um Quiz: What if re-cal is skipped?: Answer: No big problem: pos accuracy remain better 10 um! ( and is this is not enough best accuracy is just s fe clicks away (no new indent required) October 24,

33 h Model, Hertz= Hertzian contact Extraction of Load-Frame stiffness from Hertzian contact modeling 3F Er R = h Experiment With: Tip radius R from AFM (calculations with radius as function of depth (R(h)) Best Fit for 3 reference materials (Fused Silica, Sapphire 0001 and Si 100) F S i Overall system stiffness: ~2.5 N/um (good agreement with 2.2 N/um from elasticplastic indentation (F/S^2)) October 24,

34 Surface Roughness measurement Fused Silica, Contact, 256pts/ln October 24,

35 Optical Microscope Silicon or smooth, reflective surfaces in Bright-field Skin or rough, absorbing surfaces: Dark-field 2.5x 5x 8x 10x optional 20x 50x AFM BF Vs. dark-field DF 2.5x 2.5x Standard FOV All pixels Resolution ~500nm opt; ~1.7 nm afm scanner >3000x total magnification + digital zoom Bright-field illumination; Optional: Extra objectives & Dark-field October 24,

36 Hardness measurement with Sharp (cone/pyramid) - the traditional way Static Concept: 1. Apply load 2. Analysis of residual imprint after load removal Apply static concept with NanoForce 1. Apply loading profile + (static load) Calculate number F HV = d (OM image) Direct method. -difficult to co-relate to physical properties -No elastic properties [Applied load] = kgf [Diagonal] = mm 2. Direct measurement of actual- or projected contact area A c by AFM 3. Calculate Hardness 4. Convert to other hardness scales. October 24,