3D Patterning

The best 3D patterning is achieved when the following conditions are met:

  • A high writer temperature is used (>950 °C).

  • A cantilever with a blunt tip is used.

    The NanoFrazor can remove a thick resist in a single pass but sufficient heat energy must be available to trigger its decomposition. This in turn requires good thermal contact between tip and sample. A tip with an adhesion length of 40 nm should work well.

  • Precise Write-Read Alignment.

    The NanoFrazor uses a comparison of the target and written depths to perform its automated adjustment of the electrostatic force. If the offset is incorrect the feedback loop will not correctly compare the target and written depths. The offset should be measured by first writing a pattern with a single depth level in a test (unused) area of the sample and then using the automatic offset detection.

  • Adjustment of the depth feedback has been performed.

    The NanoFrazor needs some patterning data to perform its automated adjustment of the electrostatic force. This data is retained when starting a new write process. A test copy of the desired pattern should be written in an unused part of the sample using the feedback. This will initialise the force levels ready for writing the desired pattern.

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Figure 20 3D spiral phase plate written into PPA.