Double-pass modulated differential confocal microscopy for closed-loop axial control of direct laser writing

Johannes Belkner; Jaqueline Stauffenberg; Christian Görner Tenorio; Ingo Ortlepp; Eberhard Manske

doi:10.1117/12.2673874

15 August 2023 Double-pass modulated differential confocal microscopy for closed-loop axial control of direct laser writing

Johannes Belkner, Jaqueline Stauffenberg, Christian Görner Tenorio, Ingo Ortlepp, Eberhard Manske

Author Affiliations +

Proceedings Volume 12618, Optical Measurement Systems for Industrial Inspection XIII; 126180R (2023) https://doi.org/10.1117/12.2673874
Event: SPIE Optical Metrology, 2023, Munich, Germany

Abstract

Direct laser writing is a popular method for mask-less lithography that already achieved commercial grade. However, it is still challenging to realize homogeneously exposed structures on 3D-shaped substrates. A common source of the variation in exposure is a changing distance of the substrate surface with the photoresist towards the plane of the narrowest waist of the exposure beam. To tackle this issue, we propose a differential confocal probe that employs a spatially modulated pinhole. This phase-modulated lock-in principle enables highly resolved depth sensing without ambiguity about the direction of the deviation from the focal plane. However, the modulation contrast must be high enough to achieve this, which is why the measuring beam passes the pinhole twice. This probe is integrated into the nanopositioning and nanomeasuring machine via a position-based controller. We demonstrate the capability to follow 10◦ inclined substrates.

Conference Presentation

Citation Download Citation

Johannes Belkner, Jaqueline Stauffenberg, Christian Görner Tenorio, Ingo Ortlepp, and Eberhard Manske "Double-pass modulated differential confocal microscopy for closed-loop axial control of direct laser writing", Proc. SPIE 12618, Optical Measurement Systems for Industrial Inspection XIII, 126180R (15 August 2023); https://doi.org/10.1117/12.2673874

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available