Overlay budget considerations for an all-scanner fab

Rolf Seltmann; Wolfgang Demmerle; Marc Staples; Anna Maria Minvielle; Bernd Schulz; Sven Muehle

doi:10.1117/12.388935

5 July 2000 Overlay budget considerations for an all-scanner fab

Rolf Seltmann, Wolfgang Demmerle, Marc Staples, Anna Maria Minvielle, Bernd Schulz, Sven Muehle

Proceedings Volume 4000, Optical Microlithography XIII; (2000) https://doi.org/10.1117/12.388935
Event: Microlithography 2000, 2000, Santa Clara, CA, United States

Abstract

According to the SIA roadmap an overlay of 65nm is necessary for state of the art 0.18micrometers processes. To meet such tight requirements it is necessary to know the magnitude of all contributions, to understand possible interactions and to try to drive every individual overlay component to its ultimate lower limit. In this experimental study we evaluate the impact of different contributions on the overall overlay performance in a fab equipped exclusively with ASML step and scan systems. First we discuss the overlay performance of advanced step and scan systems in a mix and match scenario, focusing on single machine overlay, long term stability and multiple machine matching. We show that both distortion and stage differences between different tools are typically less than 22nm, justifying a multiple machine scenario without significant loss of overlay performance. In the next step, we discuss the impact of layer deposition and CMP. We include shallow trench isolation, tungsten-CMP as well as conventional aluminum wiring and copper-dual-damascene technology into our examinations. In particular, we discuss the pro's and con's of using a zero-layer-mark-approach, compared to an alignment on marks formed in certain layers for direct layer to layer alignment. Furthermore, we examine the performance of ASMLs 'through-the-lens' (TTL)-alignment system becomes as small as 6nm using TTL-alignment. For marks directly affected by CMP-processes technology impact can be controlled within 13nm. We show that, even in a scenario with multiple tools matched to each other, where alignment marks are directly affected by a CMP process step, and where the standard TTL alignment marks are directly affected by a CMP process step, and where the standard TTL alignment system is used, the overall overlay can be controlled within 60nm. Using the ATHENA alignment system, a further improvement is possible.

Citation Download Citation

Rolf Seltmann, Wolfgang Demmerle, Marc Staples, Anna Maria Minvielle, Bernd Schulz, and Sven Muehle "Overlay budget considerations for an all-scanner fab", Proc. SPIE 4000, Optical Microlithography XIII, (5 July 2000); https://doi.org/10.1117/12.388935

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