CPL mask technology for sub-100-nm contact hole imaging

Kasprowicz, Bryan S.; Conley, Willard E.; Litt, Lloyd C.; Broeke, Douglas J. Van Den; Montgomery, Patrick K.; Socha, Robert; Wu, Wei; Lucas, Kevin; Roman, Bernard J.; Chen, J. Fung; Wampler, Kurt E.; Laidig, Thomas L.; Progler, Christopher J.; Hathorn, Michael E.

doi:10.1117/12.557755

Cited by 2 publications

(3 citation statements)

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“…Previous publications have discussed the limitations of i-line pattern generation for second level strong PSM applications 6,7 . Prior to the introduction of DUV pattern generators, the only viable alternative was 50keV e-beam mask writers.…”

Section: Discussionmentioning

confidence: 99%

“…Although chrome features define the quartz trench edges, second layer resist edge placement is important because it determines how tightly features can be packed on the mask. Another type of PSM that has received wide interest is chromeless phase lithography (CPL), in which two closely spaced phase transitions on the mask create a dark feature 5,6,7 . In CPL it is the first mask patterning step that defines the etched quartz regions, and then the second patterning step selectively removes chrome.…”

Section: Introductionmentioning

confidence: 99%

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Second level exposure for advanced phase shift mask applications using the SLM-based Sigma7300 DUV mask writer

et al. 2005

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Phase shifting mask (PSM) development activity is increasing as 193nm optical lithography is extended beyond the 90nm technology node. The requirements on second level mask patterning of advanced PSM have for many applications exceeded the capability of i-line pattern generators, and it is natural for deep-ultraviolet (DUV) pattern generators to be employed for this task. The Sigma7300 DUV mask writer has the attributes required for advanced PSM applications: high resolution, tight CD uniformity and pattern placement, an accurate alignment system, and grid matching to first level exposures. The paper reports system performance for the parameters that constitute the error budget for second level patterning and shows that the mask writer is suitable for second level patterning of advanced PSMs. The alignment system employs the same laser and optics that are used for system calibration and exposure, including a CCD camera that links system calibration to alignment. As a result overlay performance is stable, and is shown to be independent of alignment mark image contrast changes due to different mask materials or resist thicknesses. The mask process uses a conventional chemically amplified resist, and does not require the use of charge dissipating top layers. Combined with throughput that is essentially independent of pattern complexity, DUV pattern generation provides a high yield solution for second level patterning of advanced PSMs for the 65nm and 45nm nodes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Second level exposure for advanced phase shift mask applications using the SLM-based Sigma7300 DUV mask writer

et al. 2005

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“…The mask manufacturability is discussed in reference [5]. Starting from a COG blank, the first reticle print consists of the etching of the CH and the slots of identical phase through the Cr and the glass.…”

Section: Mask Making and Case Optimizationmentioning

confidence: 99%

Through-pitch low-k 1 contact hole imaging with CPL technology

Wiaux

Bekaert

Chen³

et al. 2004

SPIE Proceedings

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Chromeless-Phase Lithography (CPL TM ) combined with IML TM (Interference Mapping Lithography) technology is experimentally demonstrated as a viable resolution enhancement technique (RET) to pattern low-k1 (0.39) contact holes (CHs) from dense through sparse pitches. Both the process latitude and the MEEF values are measured. The most promising single exposure techniques combine off-axis-illumination (OAI) with the use of non-printing assist features, as in the case of CPL with IML. Contrary to other RETs, CPL does not use sub-resolution assist features but non-printing assist slots with a well-chosen phase (180 o or 0 o ) and transmission (0% or 100%) assignment. The optimization and the positioning of assist features result of IML, based on a mapping of the field intensity at the wafer level: the assist features interfere to enhance the image at the contact hole location. The experimental layout optimization is discussed, showing how the process is maximized together with the dose-margin before any side-lobe printing. Using ArF immersion lithography at 0.75 NA with Quasar 20 o σ out =0.92 / σ in =0.72, the CPL printing performance of 100 nm contact holes, from 200 nm pitch through isolated, is measured. The Depth-Of-Focus at 8% Exposure Latitude (DOF @ 8% EL) remains above 0.4 µm through pitch, with 0.43 µm DOF @ 8% EL at the difficult 300 nm pitch. The MEEF becomes a multi-dimensional metric on CPL masks. The wafer CD uniformity depends not only on the size variation of the CH on the reticle, but also on the size variations at the two reticle write steps, i.e. the assist slots opening and the Cr removal. The MEEF metrics related to the CH and slot sizes appear as the most critical ones. For each of those parameters, measured MEEF is always below 3.

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CPL mask technology for sub-100-nm contact hole imaging

Cited by 2 publications

References 0 publications

Second level exposure for advanced phase shift mask applications using the SLM-based Sigma7300 DUV mask writer

Second level exposure for advanced phase shift mask applications using the SLM-based Sigma7300 DUV mask writer

Through-pitch low-k 1 contact hole imaging with CPL technology

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