Spatial frequency multiplication techniques towards half-pitch 10nm patterning

Abstract

Novel patterning approaches are explored to enable either more cost-effective manufacturing solutions or a potential paradigm shift in patterning technology. First, a simplified self-aligned quadruple patterning (SAQP) process is developed to extend 193nm immersion lithography to half-pitch 10nm patterning. A detailed comparison with other SAQP schemes is made, and we find the simplified SAQP process can significantly reduce process complexity and costs. On the other hand, the topographic effect on the spacer width causes difficulty in obtaining lines with equal CD, thus a CVD/etch solution must be searched to meet the CDU requirement.Moreover, a motion-induced frequency multiplication (MIFEM) concept is proposed; and specifically, we develop a stress-induced frequency multiplication (SIFEM) technique to produce half-pitch 9nm lines/spaces with no need of ebeam, imprint, or self-assembly technology. It allows us to apply standard semiconductor fabrication processes and equipment to drive down the half pitch of a spatially periodic pattern below 10nm. The resolution of this patterning technique is dependent on the CD of spacers and their gaps regardless of optical resolution of the lithographic tool. The final space CD is mainly related with the material property of the fluid used in SIFEM process. The main issues of SIFEM process include: adjusting the fluid property to tune the gap CD, designing the anchor structures and line route to control the strength and direction of film stress, and overlay methodology development, etc.Keywords: self-aligned quadruple patterning (SAQP), stress-induced frequency multiplication (SIFEM) SIMPLIFIED SELF-ALIGNED QUADRUPLE PATTERNINGSpacer self-aligned double patterning (SADP, [1]) combined with 193nm immersion lithography (single-exposure resolution at about 38nm) can drive the half pitch down to about 19nm. A straight forward method to further double the spatial frequency (i.e., about 10nm half pitch) is the self-aligned quadruple patterning (SAQP) technique [2].Two examples of the SAQP process to enable line/space density quadrupling are shown in Fig. 1. In both schemes, top APF mandrel/core (Advanced Patterning Film, a hard mask material developed by Applied Materials, Inc.) is patterned first. After that, nitride spacer is formed and APF core is stripped by an oxygen plasma etch. The main difference between scheme 1 and 2 is: nitride spacer in scheme 1 is transferred to the bottom APF which becomes the core of the second spacer (nitride); while in scheme 2, the second spacer (poly Si) is directly formed on nitride spacer. Apparently, the bottom APF core in scheme 1 has a symmetric shape which helps to form more uniform spacer structures. Direct spacer-on-spacer scheme 2 suffers from the more difficult CD control of final structures due to the asymmetric profile of the nitride spacer. In scheme 1, the bottom APF core is then stripped (in scheme 2, nitride is removed by phosphoric acid which does not attack poly Si and oxide), leaving the second spacers and resulting in spati...

Fabrication of Sub-10 nm Metal Wire Circuits using Directed Self-Assembly of Block Copolymers

“…4. They show that HP 10 nm open and short PL-TEG circuit patterns were successfully fabricated using the combined process without the use of any multi-patterning, such as self-aligned quadruple patterning [26][27][28]. Figure 6 shows cross-sectional STEM profiles of metal wire circuits with 9 nm in width after metal deposition and chemical mechanical polishing (CMP).…”

Mandrel/spacer engineering-based patterning and metallization incorporating metal layer division and rigorously self-aligned vias and cuts (SAVC)

“…Mandrel/spacer engineering based self-aligned multiple patterning (SAMP [10][11][12][13][14][15][16][17][18][19]) techniques have been applied to fabricate advanced logic/DRAM critical layers. Various SAMP schemes, e.g., double (SADP), triple (SATP), quadruple (SAQP), sextuple (SASP), octuple (SAOP) techniques have been reported.…”

“…However, its scalability is limited due to the significantly increased process complexity and mask number when extended to more aggressive density-multiplication scenarios. In general, self-aligned quadruple/octuple patterning (SAQP/SAOP) is more capable of increasing the pattern density of 1-D features; while self-aligned triple/sextuple patterning (SATP/SASP) is beneficial to reducing the process complexity by allowing more CD/design freedom and requiring fewer masks [10][11][12][13][14][15][16][17][18][19]. Table 1.…”

Mandrel and spacer engineering based self-aligned triple patterning

“…First, a wet trimming process was adopted to shrink mandrel line CD and smooth out high frequency components of LER spectrum [8]. To clear the residues, we proposed to use a "soft" material such as amorphous or poly-Si (or SiGe) as the first spacer and strip it with a highly selective dry plasma process.…”