Chemical metrology on latent resist images

• Published in: Micro and Nano Engineering Vol. 19; p. 100181
• Main Authors: van Es, Maarten, Tamer, Selman, Bloem, Elin, Fillinger, Laurent, van Zeijl, Elfi, Maturová, Klára, van der Donck, Jacques, Willekers, Rob, Chuang, Adam, Maas, Diederik
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2023; Elsevier
• Subjects: IR-AFM; Latent image; Metrology; Resist; Scanning probe microscopy; Metrology; Resist; Latent image; Scanning probe microscopy; IR-AFM
• ISSN: 2590-0072; 2590-0072
• DOI: 10.1016/j.mne.2023.100181

Patterning photoresist with extreme control over dose and placement is the first crucial step in semiconductor manufacturing. However, how can the activation of modern complex resist components be accurately measured at sufficient spatial resolution? No exposed nanometre-scale resist pattern is sufficiently sturdy to unalteredly withstand inspection by intense photon or electron beams, not even after processing and development. This paper presents experimental proof that infrared atomic force microscopy (IR-AFM) is sufficiently sensitive and gentle to chemically record vulnerable yet valuable lithographic patterns in a chemically amplified resist after exposure prior to development. Accordingly, IR-AFM metrology provides long-sought insights into changes in the chemical and spatial distribution per component in a latent resist image, both directly after exposure and during processing. With these to-be-gained understandings, a disruptive acceleration of resist design and processing is expected. [Display omitted] •IR-AFM enables metrology on latent pattern in resist before development.•New opportunities identified for evaluating LER and other metrics in an early stage.•Chemical map directly related to latent pattern in contrast with topography in AFM.