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

  • 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 higly sensitive even for layer thickness below 5 nm
  • Extremely versatile technique: it gives acccess to numerous parameters which characterize multilayer structures (eg. layer thickness, refractive index, absorption, porosity).

Product Line

µSE, SE

Refractive optical design in compact realization: short optical path inside the measurement arms (reduced alignment artifact errors). Active temperature control: stabilized environment for system reli-ability enhancement. Uniqe patented high brightness light source for outstanding SNR. CCD detector array (spectrum is taken simultaneously at different wavelengths).

 

Products

SE-3000

The Ideal thin Film characterization Tool for development & Pilot Line

The SE-3000 spectoscopic ellipsometer has been designed to fit the need of development and pilot line either for microelectronic, flat panels displays and coating industries. The SE-3000 is based on a GES5E; it can be mounted with two FOUP loadports, high speed stage, handling robot and a fast pre-alignment station for wafer to achieve equivalent throughput than production tools. The SE-3000 has the same characteristics than the GES5E in term of spectral range, Performances and spot size.

A top frame with Hepa Filter and a production type software can be added to the SE-3000.

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µSE-2500

Microspot spectroscopic ellipsometer for patterned wafer applications.

Features and System specifications:

  • DUV to Visible Ellipsometer in standard configuration
  • Ellipsometer hardware: SE-RCE (rotating compensator) - high precision and accuracy
  • Wavelength Range: 193 - 900 nm
  • Measurable Box Size: 50 μm
  • Fully automated characterization
  • User friendly software SAM, compatible with SEMI® standard (E95-0200)
  • Special designed optics for small spot
  • CognexPatmax® Pattern recognition
  • High accuracy automatic XYZ mapping stage
  • Fast Omron Automatic focus
  • Optical pre-aligner

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

Options:

  • Metrology options (additionally to the standard spectroscopic ellipsometry):
    • Spectroscopic reflectometry (SR)
    • Photoluminescence (PL)
    • Raman spectroscopy
  • Loading:
    • 150/200 mm or 200/300 mm compatibility
    • FOUP, SMIF and/or open cassette configuration

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