Self-aligned double patterning

Self-aligned double-patterning (SADP) scheme... 

Figure 17.19 Process sequence for self-aligned double-patterning technique by means of sidewall spacer formation.

Figure 17.20 SEM images of shallow trench isolation structures patterned with self-aligned double-patterning technique through various stages of the process flow, and ending in 22-nm half-pitch structures. The HM used is Applied Materials Corporation s advanced patterning film (APF). ...

The LELE approach can in principle be applied to arbitrary patterns by appropriately splitting into mask levels. While the LELE approach has been demonstrated to work in production environments, it has the disadvantage of doubling the cost of patterning for the critical layers. Another limitation is the effect of overlay error on the space CDs overlay errors translate directly into CD errors, as shown in Figure 3.8. This places severe demands on the overlay accuracy of future exposure tools. Self-aligned spacers for double patterning could avoid this issue. ... 

Figure 10 Schematics of directed self-assembly of block copolymers with a natural period of Pbcp on chemical patterns, (a) Chemical epitaxy based on dense chemical patterns of alternating preferential wetting stripe with a pitch of patterned substrate (Ls) close to Lo. The affinity between chemical patterns and block copolymer domains drives the self-alignment of block copolymer, (b) Sparse chemical patterns composed of alternating pinning stripes (width = 0.5io) and neutral stripes (width = Lk = Ls Lo) with a pitch which is twice the pitch of block copolymers (Ls/Lo 2). The self-assembled block copolymer doubles the spatial frequency of the underlying guiding chemical patterns. One domain of the block copolymers is selectively removed to show the self-assembled line-space patterns.

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