Application

THIN FILM THICKNESS MEASUREMENT

 

As the semiconductor industry continues to fulfill Moore’s law, thin film thickness is one of the most rapidly scaled dimensions. Consequently, chip manufacturers must implement metrology systems that will be effective for statistical process control of ultra-thin dielectrics.

Ellipsometry is a non-destructive technique, capable of being used for any transparent and semitransparent medium. It can measure a wide range of layer thickness from a fraction of mono-atomic layer to several micrometers.

Ellipsometry allows the determination of the thickness of single layers and multi-layer stacks. In addition, it allows the absolute characterisation of optical properties of materials by extraction of the N and K data.

Using Spectroscopic Ellipsometry, up to 7 layers can be analysed simultaneously in one measurement in order to extract the thickness of every individual layer. Material optical properties also, can be obtained over a wide spectral range, from Deep UV to near InfraRed.

Unlike other optical techniques, this method requires neither reference sample nor reference beam like reflectometry. Moreover, ellipsometry has the advantage of high sensitivity due to the additional measurement of the phase of light at different wavelengths. As a consequence, it allows analysis of complex structures like multi-layers with rough interfaces and unknown material composition.

 

 

Technology

SPECTROSCOPIC ELLIPSOMETRY

 

In the semiconductor industry, there is continuous demand for higher performance and denser integrated circuits. These requirements push the advancement of technology which requires solving of manufacturing challenges. A key to success is to understand the chemical, mechanical and physical properties of wide range of materials used in a typical integrated circuit.

The µSE tool is designed to measure thin film thickness and optical properties inside a <50µm test pad on semiconductor product wafers. The applied measurement technique for obtaining these parameters in a high accuracy and repeatable way is spectroscopic ellipsometry. The μSE tool uses optimized spectroscopic ellipsometer (SE) arms and optics for the measurement inside small boxes of patterned Si wafers.

Ellipsometry measures the phase of the reflected light from the sample, therefore it is relatively insensitive for intensity fluctuations. The raw measurement data represent the complex information from the layer stack which then need to be modeled optically. The measurement results are obtained through numerical regression process of the model data to the raw measurement spectrum.

 

TYPICAL SE REGRESSIONS: 

FEATURES

 

Optical solutions and design

  • Stable, robust mechanical design
  • Compact refractive optical design: short optical path inside the measurement arms (reduced alignment artifact errors)
  • High precision Rotating Compensator metrology
  • Uniqe patented high brightness light source for outstanding SNR
  • High accuracy stage for X-Y mapping with fast optical autofocus
  • Active temperature control for system reliability enhancement
  • Available options: Spectroscopic Reflectometry / Bow-Warp / Global Stress / Raman / Spectral Photoluminescence

Measurement thickness ranges

  • UV-VIS ellipsometer head (1 nm - 8μm)
  • NIR reflectometer head (1μm - 30μm)
  • Thick layer optical distance sensor (30μm - 300μm)

Product Line

µSE, SE

SEMILAB SE Series are state of the art, cost effective ellipsometers addressing semiconductor More-than-Moore, III-V (GaN, InGaAs), Micro (O)LED industry. With more than 30 years of experience in ellipsometry, SEMILAB offers an extensive application knowledge and library to support start production and long-term development.

Benefits:

  • Non-destructive optical technique, based on measurement of the change of the polarisation state of light after reflection at non normal incidence on the surface to study.
  • It is a highly sensitive even for layer thickness below 1 nm
  • Extremely versatile technique: it gives acccess to numerous parameters which characterize multilayer structures (eg. layer thickness, refractive index, absorption, porosity).

Applications

Thin film dielectric or semiconductor layer stack on solid polished surface substrate is the main target of applications.

Pattern-capable Spectroscopic Ellipsometry:

  • On high-performance silicon CMOS or III/V devices
  • After deposition and etch processes
  • Measurement capability of product wafers in <50μm patterned test areas

OLED display applications:

  • Multilayer characterization
  • Thickness, n, k measurement
  • Thickness map within sub-pixels

More than Moore (MtM) industrial applications:

  • Compound materials measurements:
    • AlGaN, GaN, GaAsOx,
    • SiGe, Poly-Si with Raman extension
  • Graphene, CNT
  • Periodic thick layers definition

Products

µSE-3000 Microspot Spectroscopic Ellipsometer

Microspot spectroscopic ellipsometer of Semilab are capable of fully automated characterization of patterned, compound or (O)LED 300 mm samples. 

Applications:

  • Primary applications:
    • Front-end applications
    • Production wafer monitoring
    • Process development
  • Advanced Process Control:
    • Across wafer uniformity
    • Wafer to wafer uniformity
    • Batch to batch uniformity

Features and System specifications:

  μSE/SE-3000
Wavelength range UV-VIS
193 nm - 900 nm
Angle of incidence basic AOI 70°(possible 75°)
Measurement spot size 35 x 40 μm (μSE) / 365 x 400 μm (SE)
Mapping area Max. 300 mm diameter
Mapping point options User defined mapping point options,
up to 3 000 points
Edge exclusion < 0,5 mm
Lamp lifetime 8000 hrs
Loadport type    Dual loadports with OHT capability and SECS/GEM   
2 FOUPs with bridge compatibility
Sample sizes 300 mm / 200 mm (with cassette insert)
Sample materials Transparent (glass), Si, GaAs, SiC, etc.

Options:

In order to address great variety of applications SE systems can be combined with other metrologies additionally to the standard spectroscopic ellipsometry.

Metrology options:

  • Spectroscopic reflectometry (SR)
  • Bow-Warp 
  • Global Stress
  • Raman Spectroscopy
  • Spectral Photoluminescence
  μSR SR
Spot size 50 μm (VIS) /
0.5 mm (NIR)
    30 μm (UV-VIS) /   
50 μm (NIR)
Wavelength range 380 nm - 2100 nm 193 nm -1700 nm
Evaluation method    Spectrum (VIS) /
  Spectrum or FFT-based (NIR)  
Spectrum and
FFT-based

 

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µSE / SE-2200 Microspot Spectroscopic Ellipsometer

Microspot spectroscopic ellipsometer of Semilab are capable of fully automated characterization of patterned, compound or (O)LED samples up to 200 mm. 

Applications:

  • Primary applications:
    • Front-end applications
    • Production wafer monitoring
    • Process development
  • Advanced Process Control:
    • Across wafer uniformity
    • Wafer to wafer uniformity
    • Batch to batch uniformity

Features and System specifications:

  μSE/SE-2200
Wavelength range UV-VIS
193 nm - 900 nm
Angle of incidence basic AOI 70°(possible 75°)
Measurement spot size 35 x 40 μm (μSE) / 365 x 400 μm (SE)
Mapping area Max. 200 mm diameter
Mapping point options User defined mapping point options,
up to 3 000 points
Edge exclusion < 0,5 mm
Lamp lifetime 8000 hrs
Loadport type    Dual loadports with OHT capability and SECS/GEM   
2 cassettes with SMIF compatibility
Sample sizes 100 / 150 / 200 mm
Sample materials Transparent (glass), Si, GaAs, SiC, etc.

Options:

In order to address great variety of applications SE systems can be combined with other metrologies additionally to the standard spectroscopic ellipsometry.

Metrology options:

  • Spectroscopic reflectometry (SR)
  • Bow-Warp 
  • Global Stress
  • Raman Spectroscopy
  • Spectral Photoluminescence
  μSR SR
Spot size 50 μm (VIS) /
0.5 mm (NIR)
    30 μm (UV-VIS) /   
50 μm (NIR)
Wavelength range 380 nm - 2100 nm 193 nm -1700 nm
Evaluation method    Spectrum (VIS) /
  Spectrum or FFT-based (NIR)  
Spectrum and
FFT-based

 

Request Info