Double patterning for 32nm and below: an update

Finders, Jo; Dusa, Mircea V.; Vleeming, Bert; Megens, Henry; Hepp, Birgitt; Maenhoudt, Mireille; Cheng, Stone; Vandeweyer, T.

doi:10.1117/12.772780

Cited by 54 publications

(44 citation statements)

References 2 publications

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“…Whenever two patterns are formed in different exposure and etch steps, lines and spaces have bimodal CD distributions [31] that can have severe implications for the digital design flow [32]. Because the same mask is used for both exposures in ST-DPL, mask CDU, which is the second most important contributor to the overall CD variation as reported in [31,33], no longer affects the difference between the two distribution and the bimodal problem is alleviated.…”

Section: B Alleviating CD Bimodality Problemmentioning

confidence: 99%

Single-Mask Double-Patterning Lithography for Reduced Cost and Improved Overlay Control

Ghaida

Torres

Gupta

2011

IEEE Trans. Semicond. Manufact.

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Abstract-1 We propose shift-trim double patterning lithography (ST-DPL), a cost-effective double patterning technique for achieving pitch relaxation with a single photomask. The mask is re-used for the second exposure by applying a translational mask-shift. An additional non-critical trim exposure is applied to remove extra printed features. ST-DPL can be used to pattern critical layers and is very suitable for regular and gridded layouts, where redesign effort and area overhead are minimal. In this paper, the viability of ST-DPL is demonstrated through a design implementation at the poly and contacts layers in bidirectional layouts. Standard-cell layouts are constructed so as to avoid layout decomposition conflicts, which are found to be the limiting factor for the pitch relaxation that can be achieved with double-patterning (ST-DPL as well as standard DPL). 2× pitch relaxation being associated with a considerable area overhead, 1.8× pitch relaxation is achieved in our implementation while ensuring no layout decomposition conflicts and a small area overhead. Specifically, in comparison to layouts assumed to be feasible with a hypothetical single-patterning process, we observe virtually no area overhead when ST-DPL is applied to the poly layer (<0.3% cell-area overhead) and no more than 4.7% cellarea overhead when ST-DPL is applied at both the poly and contacts layers. The proposed method has many benefits over standard pitch-split double-patterning: (1) cuts mask-cost to nearly half, (2) reduces overlay errors between the two patterns, (3) alleviates the bimodal line-width distribution problem in double patterning, and (4) slightly enhances the throughput of critical-layer scanners.

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Section: B Alleviating CD Bimodality Problemmentioning

confidence: 99%

Single-Mask Double-Patterning Lithography for Reduced Cost and Improved Overlay Control

Ghaida

Torres

Gupta

2011

IEEE Trans. Semicond. Manufact.

View full text Add to dashboard Cite

show abstract

“…Whenever two patterns are formed in different exposure and etch steps, lines and spaces have bimodal CD distributions [2] that can have severe implications for the digital design flow [26]. Since in ST-DPL the same mask is used for both exposures, mask CDU, which is the second most important contributor to the overall CD variation as reported in [2,3], no longer affects the difference between the two distribution and the bimodal problem is alleviated.…”

Section: Alleviating CD Bimodality Problemmentioning

confidence: 99%

“…Since in ST-DPL the same mask is used for both exposures, mask CDU, which is the second most important contributor to the overall CD variation as reported in [2,3], no longer affects the difference between the two distribution and the bimodal problem is alleviated.…”

Section: Alleviating CD Bimodality Problemmentioning

confidence: 99%

“…Using line-CDU breakdown values for LELE positive dual-line 32nm process from [2] (i.e. 2.7nm 3σ from etch, 1.4nm 3σ from mask-CDU, 0.7nm 3σ from dose, and 0.5nm 3σ from focus), σ dif f is 1.49nm in the case of standard-DPL and 1.34nm in the case of ST-DPL which corresponds to a 10.3% reduction in standard deviation.…”

Section: Alleviating CD Bimodality Problemmentioning

confidence: 99%

See 1 more Smart Citation

Single-mask double-patterning lithography

2009

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This paper proposes shift-trim double patterning lithography (ST-DPL), a cost-effective method for achieving 2× pitchrelaxation with a single photomask (especially at polysilicon layer). The mask is re-used for the second exposure by applying a translational mask-shift. Extra printed features are then removed using a non-critical trim exposure. The viability of ST-DPL is demonstrated. The proposed method has many advantages with virtually no area overhead (< 0.3% standard-cell area): (1) cuts mask-cost to nearly half that of standard-DPL, (2) reduces overlay errors between the two patterns and can virtually eliminate it in some process implementations, (3) alleviates the bimodal problem in doublepatterning, and (4) enhances throughput of first-rate scanners. We implement a small 45nm standard-cell library and small benchmark designs with ST-DPL to illustrate its viability.

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“…To achieve this milestone, liquid immersion lithography and extreme ultraviolet (EUV) lithography can be expected to be among the most commonly used techniques for the fabrication of nanopatterns. With liquid immersion lithography using a wavelength of 193 nm and a high numerical aperture (NA), it has been demonstrated that 32 nm features can be patterned (Finders et al, 2008;Sewell et al, 2009). EUV lithography using a short wavelength of 13.5 nm and 0.3-NA exposure tool has also enabled the printing of 22 nm half-pitch lines (Naulleau et al, 2009).…”

Section: Introductionmentioning

confidence: 99%