page_title: Multiple patterning
section_title: Mixed patterning methods
hierarchical_section_title: Multiple patterning / Multipatterning Implementations / Mixed patterning methods
caption_attribution_description: English: SAQP combined with selective SADP blocking is an example of the crossed multiple patterning combined with self-aligned blocking, described by TEL and w:Mentor Graphics,&#91;1&#93;&#91;2&#93;&#91;3&#93;&#91;4&#93;&#91;5&#93; as well as Coventor and IMEC.&#91;6&#93; Negative spacers&#91;7&#93; are also assumed here.
context_page_description: Multiple patterning is a class of technologies for manufacturing integrated circuits, developed for photolithography to enhance the feature density. It is expected to be necessary for the 10 nm and 7 nm node semiconductor processes and beyond. The premise is that a single lithographic exposure may not be enough to provide sufficient resolution. Hence additional exposures would be needed, or else positioning patterns using etched feature sidewalls would be necessary.
  Even with single exposure having sufficient resolution, extra masks have been implemented for better patterning quality such as by Intel for line-cutting at its 45nm node or TSMC at its 28nm node.
  Even for electron-beam lithography, single exposure appears insufficient at ~10 nm half-pitch, hence requiring double patterning.
  Pitch double-patterning was pioneered by Gurtej Singh Sandhu of Micron Technology during the 2000s, leading to the development of 30-nm class NAND flash memory. Multi-patterning has since been widely adopted by NAND flash and RAM memory manufacturers worldwide.
context_section_description: Multiple patterning is evolving toward a combination of multiple exposures, spacer patterning, and/or EUV. Especially with tip-to-tip scaling being difficult in a single exposure on current EUV tools, a line-cutting approach may be necessary.
  IMEC reported that double patterning is becoming a requirement for EUV.
  Mixed patterning with overlay sensitivity:
  Mixed patterning with reduced overlay sensitivity:
  For line patterning, SADP/SAQP could have the advantage over the EUV exposure, due to cost and maturity of the former approach and stochastic missing or bridging feature issues of the latter. For grid location patterning, a single DUV exposure following grid formation also has the cost and maturity advantages (e.g., immersion lithography may not even be necessary for the spacer patterning in some cases) and no stochastic concerns associated with EUV. Grid location selection has an advantage over direct point cutting because the latter is sensitive to overlay and stochastic edge placement errors, which may distort the line ends.
caption: SAQP with selective SADP blocking. SAQP combined with SADP for selective blocking is the expected approach for 10 nm half-pitch patterning without EUV.
exif: {}