Measurement Technology Quick Selection Guide

Three Steps to Find the Right Solution: By Material, Measurement Item, and Film Thickness

Nine Technology Codes T1–T9, Consistent with the "Integrated Wafer and Thin Film Measurement Solutions"

Code Technology Name Key Measurement Items Application Features
T1 IR White Light Interferometry Wafer Thickness・TTV Wafer Geometry
T2 Multi-peak Interferometric Displacement Multi-layer Thickness＋Warpage Thick Film / Si / Haze Film
T3 Broadband Spectral Interferometry Si Penetration・Coated Films Thin Film & Surface Optics
T4 High-penetration Spectral Interferometry Haze Films・EMC・Thick Films Thick Film / Si / Haze Film
T5 Reflectance Spectroscopy Thin Film d・n・k・Map Thin Film & Surface Optics
T6 Spectroscopic Ellipsometry Ultra-thin Films・Precise n/k Thin Film & Surface Optics
T7 Monochromatic Light Interferometry Surface Roughness Thin Film & Surface Optics
T8 Line Confocal 3D Scanning 3D Topography・Bumps・Steps Thin Film & Surface Optics
T9 Dual-probe Caliper Measurement Opaque Wafer Thickness Opaque Materials

Selection Guide: Three Questions to Determine Measurement Technology

STEP 1 What to measure?
Thickness / TTV, Warpage | Multi-layer Thickness | Film Thickness & n, k | 3D Topography / Roughness
STEP 2 Material Optical Properties?
Transparent: Glass, LN, Sapphire | Si: Requires SWIR IR band | Haze / EMC: High scattering | Metal Coatings: Opaque
STEP 3 Thickness of Each Layer?
≥ 10 µm → T2 | 0.3–10 µm → T3 | 10 nm–several µm → T5 | < 100 nm → T6

Example: LN 20 µm bonded to glass, measuring TTV＋Warpage → Transparent → ≥ 10 µm per layer → T2 Multi-peak Interferometric Displacement, completed with a single probe

STEP 1 ｜ By Measurement Item: Technology Mapping

Measurement Item Wafer Thickness / TTV Warpage / Bow / Warp Multi-layer Thickness Thickness＋Refractive Index n, k Haze Film / EMC Thickness 3D Topography / Bumps / Steps Surface Roughness Ra / Rz
T1 IR White Light Interferometry Primary Primary Conditional        
T2 Multi-peak Interferometric Displacement Primary Primary Primary        
T3 Broadband Spectral Interferometry Primary Conditional Primary Primary      
T4 High-penetration Spectral Interferometry Conditional Conditional Primary   Primary    
T5 Reflectance Spectroscopy     Primary Primary      
T6 Spectroscopic Ellipsometry     Conditional Primary      
T7 Monochromatic Light Interferometry           Conditional Primary
T8 Line Confocal 3D Scanning   Conditional       Primary Conditional
T9 Dual-probe Caliper Measurement Primary            

Note: For transparent wafers requiring simultaneous thickness＋warpage measurement → T2; For haze films / EMC → T4

STEP 2 ｜ By Material: Material Optical Properties × Recommended Technology

Material Optical Properties Recommended Tech Notes
Glass / Quartz Transparent T2・T1・T3・T5 —
Sapphire Transparent T2・T1 —
LN / LT Piezo Wafers Transparent T2・T1 X / Y-cut double refraction, sample evaluation recommended
Si Wafers / Thinned Wafers Opaque at 840 nm T3 (SWIR 40–775 µm, penetrates backing tape)・T1 (1100 nm) T1 is used for high-doped Si
SiO₂ / SiN Dielectric Films Transparent T5・T6 Prioritize T6 for < 100 nm
Photoresist / PI / Organic Films Transparent to Translucent T3・T5・T6 Requires optical model establishment
Haze Films / EMC / Composite Films High scattering / Absorption T4 (Penetrates ~1 mm EMC) Max total thickness ≤ 3 mm, resolves up to 3 layers
Metal Coatings / Opaque Opaque T9 (Thickness)・T8 / T7 (Surface) Requires standard wafer for probe gap calibration
Bumps / Microstructures 3D Structure T8 (3D Topography)・T3 Microscopic (Thickness) —

STEP 3 ｜ By Film Thickness: Technology Distribution from 1 nm to 3 mm

  • < 100 nm ｜ Ultra-thin Films・Precise n/k: T6 Spectroscopic Ellipsometry
  • 10 nm – 350 µm ｜ Thin Film d・n・k・Map: T5 Reflectance Spectroscopy
  • 0.3 µm – 775 µm ｜ Si Penetration・Coated Films: T3 Broadband Spectral Interferometry (Film 0.3–200 µm; Si 40–775 µm)
  • 50 µm – 3 mm ｜ Haze Films・EMC・Thick Films: T4 High-penetration Spectral Interferometry
  • 10 µm – 1.3 mm (per layer) ｜ Multi-layer Thickness＋Warpage: T2 Multi-peak Interferometric Displacement
  • 1 µm – 1.4 mm ｜ Wafer Thickness・TTV: T1 IR White Light Interferometry
  • Height Resolution 200 nm ｜ 3D Topography・Bumps・Steps: T8 Line Confocal 3D Scanning (Z 2.1 mm)
  • 1–160 nm ｜ Surface Roughness: T7 Monochromatic Light Interferometry

Note: For multi-layers, look at "each layer": Above 10 µm → T2 Multi-peak interference; Thin layers below this → T3 / T5 / T6; Haze, EMC → T4

Key Point ｜ Multi-layer Structures: Combine Technologies by Layer Thickness

Stack Structure Typical Examples Recommended Tech Key Reasons
Each layer ≥ ~10 µm LN 20 µm / Glass 500 µm T2 Multi-peak Interferometric Displacement Simultaneous multi-layer thickness ＋ warpage at one point
Thick layer ＋ µm-level thin layer LN / SiO₂ bonding layer 1–2 µm / Substrate T2＋T3 or T5 (Dual probes on the same platform) T2 for thick layers ＋ Warpage; spectra covers thin layers
0.3–200 µm, 2 layers PI, PR, Oxide coated films T3 Broadband Spectral Interferometry Resolves 0.3 µm layers, < 1 s / point
Haze / EMC / Thick composite films Encapsulation EMC, Haze protective films T4 High-penetration Spectral Interferometry Penetrates ~1 mm EMC, up to 3 mm and 3 layers
nm–several µm thin film stacks SiO₂ / SiN, Optical coatings T5 Reflectance Spectroscopy Simultaneous d, n, k, full-wafer Map
< 100 nm or precise n/k required Ultra-thin dielectric films, organic films T6 Spectroscopic Ellipsometry Most sensitive for ultra-thin films, highly accurate n, k

Transmission Band

840 nm penetrates Glass / LN / Sapphire, but not Si; For Si, use T3 (SWIR) or T1 (1100 nm)

Refractive Index Difference

The closer the refractive indices of adjacent layers, the weaker the interface peak

LN Cut Direction

X / Y-cut features double refraction, sample evaluation is recommended

Quick Check ｜ Common Cases, Direct Matching

LN / LT Bonded to Glass
Thickness, TTV, Warpage
T2 Completed with a single probe
LN / LT Bonded to Si
LN Layer ＋ Si Thickness, Warpage
T2 + T3 (Si requires SWIR band)
Metallized LN / Sapphire
Total Thickness, TTV
T9 Opaque coating
Thinned Si Wafers (with backing tape)
Si Thickness, TTV, Warpage
T3 + T2 (Penetrates tape to measure true Si thickness)
Encapsulation EMC / Haze Films
Thickness, Multi-layer cross-section
T4 Penetrates ~1 mm EMC
PI / PR / Oxide Coatings
Thickness, Uniformity Map
T3 / T5 (Add T6 for ultra-thin films)
Bumps / BGA
Height, Coplanarity, 3D Topography
T8 High-speed line scanning
Ground / Polished Si Surface
Ra, Rz, 3D Topography
T7 2 seconds per point

Quick Check ｜ Technical Specifications

Specifications vary by material, refractive index, and model; subject to actual sample evaluation results

Technology Primary Application Measurement Range Accuracy / Resolution Spot Size / FOV Speed
T1 IR White Light Interferometry Wafer Thickness / TTV 1 µm–1.4 mm (Glass); Si 50 µm–1.05 mm Resolution < 1 nm; Linearity ±0.1 µm Point measurement 6 kHz
T2 Multi-peak Interferometric Displacement Multi-layer Thickness＋Warpage Z 2.1 mm; 10 µm–1.3 mm per layer, ≤ 13 layers Resolution 30 pm–1 nm; Linearity ±10–50 nm 10 µm 6 kHz
T3 Broadband Spectral Interferometry Si Thickness / Coated Films Si 40–775 µm; Film 0.3–200 µm CV < 0.1%; Resolution 0.001–0.01 µm 10 µm–1 mm < 1 s / point
T4 High-penetration Spectral Interferometry Haze Films / EMC / Thick Films 50 µm–3 mm (n=2), up to 3 layers Resolution 0.1 µm; Repeatability ≤ 0.5 µm 2 mm (WD 90 mm) 1 s / point
T5 Reflectance Spectroscopy Thickness, n, k, Map 10 nm–350 µm (Depending on band) Accuracy < 2 nm or 0.2%; Stability 0.1 nm 10–30 µm (Microscopic) 12-inch Auto Map
T6 Spectroscopic Ellipsometry Ultra-thin Films, n, k nm-level Films Δ, Ψ < ±0.3%; Thickness / n, k < ±0.3% Incident angle 45–90° —
T7 Monochromatic Light Interferometry Surface Roughness Height 1–160 nm Ra Repeatability ±0.5 nm 1.6 × 1.3 mm 2 s
T8 Line Confocal 3D Scanning 3D Topography / Bumps Line length 7 mm (2,624 pts); Z 2.1 mm Z Resolution 200 nm; Lateral 2.7 µm Line profile 10 kHz profile
T9 Dual-probe Caliper Measurement Opaque Wafer Thickness Depends on probe configuration Depends on probe; standard wafer calib. 10 µm 6 kHz

Unsure How to Choose? Send Samples to iBoson

Provide the following information to arrange an empirical evaluation and solution recommendation:

  • Materials and stack structures (material and thickness of each layer)
  • Wafer size and surface condition (polished / ground / coated / taped)
  • Measurement items and target specs (accuracy, repeatability)
  • Measurement takt time and application scenarios (R&D / Production line)

 

 

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