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Thermo Fisher Scientific

TEM Distortion 5.5%,which is out of spec(NSR Spec≤1%)

Issue

TEM Distortion 5.5%,which is out of spec(NSR Spec≤1%)

Environment

Titan Cubed G2 60-300

Resolution

These are possible resolutions for the issue:

  • Retune corrector and Replaced CGNL Board

Cause

These are possible causes for the issue:

  • Misalignment Corrector and CGNL Board faulty (INT-Lens, DL-Lens not stable)

Details

Problem statement: TEM distortion measures 5.5% versus one year ago 0.2%
Customer Success Criteria: Distortion ≤1% & Stable in all magnifications

Image Corrector tuned: HPx/y reduced to zero [Reset A2 Button], image distortion adjusted to 0.7% using TiltHP2 on Silicon sample. Used Dstg - x/y to further reduce the image distortion ≤0.2% and stable (89kx - 380kx magnifications). But significant change on magnification (55kx – 71kx) due to magnification calibration jump 6%. Proven the focus was not changed which indicated the problem is below the objective.

Health Monitoring (HM): Intermediate lens and diffraction lens shows very small instability. As the result replaced CGNL Board and the issue solved.

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