New 3D-AFM for High Resolution Sidewall Imaging

Limitations of Conventional 3D AFM

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Flare Tip

Flat and very wide bottom portion of the tip (>100nm)
Unable to produce detailed image of sidewalls
Limited accessibility to significant undercut samples
Slow scan rate & low resolution

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Tilted Step-in Tip

Essentially tilted piezotubescanning both XY & Z
Point by point mapping
Low & limited resolution due to “step-in” approach
Very slow scan rate

Innovative XE-3DM Technology Overcomes the Challenges

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High Resolution Access to Undercut and Sidewall

Two independent XY and Z flexure scanners for sample and tip
Z-scanner tilted sideway from -38^o to +38^o
Access to overhang sidewall
Use of normal high aspect ratio tips for high resolution imaging

Image of Undercut Overhang: Metal Overhang Structure

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3D View of High Resolution Sidewall Scan

Complete 3D Metrology of Sidewall
High Resolution Sidewall Roughnesss Measurement
Critical Angel Measurement of Sidewalls
Critical Dimension Measurements of Vertical Sidewalls

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Sidewall Roughness Measurement

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Undercut & Sidewall Characterization

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- Need to measure the sidewall roughness, angle and the width of bottom, middle, and top
- Characterization of soft photoresist surface by non-destructive imaging

Challenges in Accessing Sidewall

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Conventional AFM cannot get access to the sidewall, especially for overhang features

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Other methods, such as the flare tips, are insufficient in obtaining the high resolution details of the sidewall due to its dull tip. For a deeper overhang, the bottom width cannot be reached at all.

For Undercut Characterization and Sidewall Metrology

Continuing the company’s impressive track record of developing optimized solutions, Park Systems introduces XE-3DM, an automatic AFM which revolutionizes the way trench, overhang, and undercut features are scanned and analyzed. The new XE-3DM also makes possible to image soft photoresist structures without deforming or damaging it.

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Advanced Inline Automation
- Automated reference marker detection
- Automatic Data Acquisition and Analysis of Trench, Overhang, and Undercut

Features
- High Resolution Access to Undercut and Sidewall
- Non-Destructive CD and Sidewall Measurements by True Non-Contact Mode
- Soft Photoresist Structures Can Be Imaged Non-Destructively
- Critical Angle Measurement of Sidewalls
- Automatic Tip Exchange (optional)

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