193-nm immersion photomask image placement in exposure tools

Cotte, Eric; Alles, Benjamin; Wandel, Timo; Antesberger, Gunter; Teuber, Silvio; Vorwerk, Manuel; Frangen, Andreas; Katzwinkel, Frank

doi:10.1117/12.656373

Cited by 7 publications

(1 citation statement)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This may not be enough to justify the SWaP method but, again, it adds worth to the concept and to the argument for analysis of the option. Work done by AMTC and its collaborators shows residual errors of approximately (x,y) = (8 nm, 20 nm) 3-sigma when two overlaid masks are subtracted from the overlaid wafers [5]. This is an indication that the transfer function is subject to influences that are not reflected in the mask registration metrology but are significant to the wafer overlay performance.…”

Section: Registrationmentioning

confidence: 95%

Optimal mask characterization by Surrogate Wafer Print (SWaP) method

Kimmel

Hoellein

Peters

et al. 2008

Photomask Technology 2008

View full text Add to dashboard Cite

Traditionally, definition of mask specifications is done completely by the mask user, while characterization of the mask relative to the specifications is done completely by the mask maker. As the challenges of low-k 1 imaging continue to grow in scope of designs and in absolute complexity, the inevitable partnership between wafer lithographers and mask makers has strengthened as well. This is reflected in the jointly owned mask facilities and device manufacturers' continued maintenance of fully captive mask shops which foster the closer mask-litho relationships. However, while some device manufacturers have leveraged this to optimize mask specifications before the mask is built and, therefore, improve mask yield and cost, the opportunity for post-fabrication partnering on mask characterization is more apparent and compelling. The Advanced Mask Technology Center (AMTC) has been investigating the concept of assessing how a mask images, rather than the mask's physical attributes, as a technically superior and lower-cost method to characterize a mask. The idea of printing a mask under its intended imaging conditions, then characterizing the imaged wafer as a surrogate for traditional mask inspections and measurements represents the ultimate method to characterize a mask's performance, which is most meaningful to the user. Surrogate wafer print (SWaP) is already done as part of leading-edge wafer fab mask qualification to validate defect and dimensional performance. In the past, the prospect of executing this concept has generally been summarily discarded as technically untenable and logistically intractable. The AMTC published a paper at BACUS 2007 successfully demonstrating the performance of SWaP for the characterization of defects as an alternative to traditional mask inspection [1]. It showed that this concept is not only feasible, but, in some cases, desirable. This paper expands on last year's work at AMTC to assess the full implementation of SWaP as an enhancement to mask characterization quality including defectivity, dimensional control, pattern fidelity, and in-plane distortion. We present a thorough analysis of both the technical and logistical challenges coupled with an objective view of the advantages and disadvantages from both the technical and financial perspectives. The analysis and model used by the AMTC will serve to provoke other mask shops to prepare their own analyses then consider this new paradigm for mask characterization and qualification.

show abstract

Section: Registrationmentioning

confidence: 95%

Optimal mask characterization by Surrogate Wafer Print (SWaP) method

Kimmel

Hoellein

Peters

et al. 2008

Photomask Technology 2008

View full text Add to dashboard Cite

show abstract

Feasibility study of mask fabrication in double exposure technology

et al. 2006

View full text Add to dashboard Cite

Meeting overlay requirements for future technology nodes with in-die overlay metrology

Schulz¹,

Seltmann²,

Busch³

et al. 2007

SPIE Proceedings

Self Cite

View full text Add to dashboard Cite

As a consequence of the shrinking sizes of the integrated circuit structures, the overlay budget shrinks as well. Overlay is traditionally measured with relatively large test structures which are located in the scribe line of the exposure field, in the four corners. Although the performance of the overlay metrology tools has improved significantly over time it is questionable if this traditional method of overlay control will be sufficient for future technology nodes. For advanced lithography techniques like double exposure or double patterning, in-die overlay is critical and it is important to know how much of the total overlay budget is consumed by in-die components.We reported earlier that small overlay targets were included directly inside die areas and good performance was achieved 1 . This new methodology enables a wide range of investigations. This provides insight into processes which were less important in the past or not accessible for metrology. The present work provides actual data from productive designs, instead of estimates, illustrating the differences between the scribe line and in-die registration and overlay. The influence of the pellicle on pattern placement on mask and wafer overlay is studied. Furthermore the registration overlay error of the reticles is correlated to wafer overlay residuals. The influence of scanner-induced distortions (tool to tool differences) on in-die overlay is shown. Finally, the individual contributors to in-die-overlay are discussed in the context of other overlay contributors. It is proposed to use in-die overlay and registration results to derive guidelines for future overlay and registration specifications. It will be shown that new overlay correction schemes which take advantage of the additional in-die overlay information need to be considered for production.

show abstract

193-nm immersion photomask image placement in exposure tools

Cited by 7 publications

References 20 publications

Optimal mask characterization by Surrogate Wafer Print (SWaP) method

Optimal mask characterization by Surrogate Wafer Print (SWaP) method

Feasibility study of mask fabrication in double exposure technology

Meeting overlay requirements for future technology nodes with in-die overlay metrology

Contact Info

Product

Resources

About