Line and space patterns

The Figure 14 shows the cross-sectional pattern of the resist developed with a 2.38% TMAH aqueous solution. The mask had an equal line-space pattern. All the resist patterns shown in the photograph were obtained by 1.2 J/cm2 exposure and 50 second, 25°C development. The resist patterns, from 0.600micron line and space to 0.325 micron line and space, were the same as that of the mask size. However, the 0.300 micron line and space pattern was underdeveloped or under-exposured. The 0.275 micron line and space pattern was not opened. Figure 15 shows the relation between the mask size and the resist pattern size fabricated. 

Figure 2. SEM photograph of 0.4-/

Figure 11. SEM of 0.4 pm line and space patterns in a 1.2 pm thick chlorinated poly(styrene) film exposed with 250 mJ/cm2 of 248 nm light, treated with TiCl4 and developed by O2 RIE.

Figure 9 shows an SEM photograph of 0.6 micron down to 0.45 micron line-and-space patterns of the new resist in 1.0 micon film thickness exposed with KrF excimer laser stepper system (N.A. 0.36). The energy required for the pattern fabrication was only 50 mJ/cm2, and the development was done with a 60s immersion in 0.83% TMAH solution. High aspect ratio patterns of such thick resist films were successfully obtained using this resist. 

Figure 9. SEM photographs of 0.6 micron down to 0.45 micron line-and-space patterns of this new resist with 1.0 micron film thickness.

The exposure curve of the two-layer resist based on the doping process is shown in Figure 8. The two-layer resist system has a high contrast and high resolution capability. Submicron line-and-space patterns are obtained using this two-layer resist system (Figure 9). 

Figure 7. Submicron line and space patterns of 2LR with SNR/AZ resist of 1.0 thickness (a) line and space width 0.2 pm, (b) line and space width...

Figure 7 shows the SEM photographs of line and space patterns using an exposure of 10 / 2. The smallest line and space width of the 2LR pattern that was well-resolved is 0.2 . Figure 8 shows the resolution of 1LR poly-a-methylstyrene (aM-CMS) pattern and the 2LR using SNR/AZ resist. In the case of aM-CMS that is known as a high resolution negative electron resist in 1LR, the smallest line and space width is 0.4 jtm with 0.6 jim of resist thickness... 

The mixture was initially filtered through a 0.2 pm pore diameter teflon filter. It was spin-coated onto a silicon wafer previously sprayed with hexamethyldisilazane and baked for 40 seconds at 90°C and 90 seconds at 110°C, forming a 500 nm resist film. The resist film was exposed to ArF excimer laser light, heat treated for 90 seconds at 110°C, and cooled to ambient temperature. It was then dipped in 2.38% aqueous tetramethylammonium hydroxide solution for 60 seconds for development where it formed a 1 1 line-and-space pattern. The wafer as developed was... 

Exposure characteristics of X-8000K2 and conventional positive photoresist OFPR-800 (Tokyo Ohka Co.) are shown in Figure 1. X-8000K2 shows the comparable sensitivity to conventional one. Line and space and via hole patterns of X-8000K2 are shown in Figure 2. 0.8 jim line and space patterns and 1.2 m via hole patterns were obtained. 

Figure 5. Line and space patterns of PIX after RIE treatment (X-8000K2 1.2pm, PIX 2pm thick) (a) before etching, (b) etching time 18min, (c) etching time 46min.

Figure 7. Line and space pattern of FIX after HF/NH F treatment for 30 sec., L S.

Figure 9. SEM (scanning electron microscopy) micrographs of l- xm line and space patterns transferred by O 2 EIE into 1.5 xm of planarizing material.

Figure 11.13 SEM images of line-and-space patterns printed with 60-nm-thick Shipley XP-98248 resist on bare silicon and exposed at 157 nm. Process conditions postapplied bake 130°C/60 seconds, postexposure bake 130°C/90 seconds, developer 0.26N tetramethylammonium hydroxide (without surfactant) for 20 seconds. Unexposed resist loss 6nm. Exposure energy 1.35 mJ/cm. Note the significant surface inhibition layer, showing poisoning effects. ...

For the pattern profile evaluation, KrF resist was coated to a thickness of 0.7 m on a Si or TiN substrate treated with an each adhesion promoter. After e osure, PEB and the alkaline development, we observed SEM of line-and-space pattern profiles. A 0.7 pt m thick KrF excimer laser positive chemically amplified resist with acid-labile protecting group was used. 

Resist Pattern Profiles. Figure 8 shows 0.24 pi m line-and-space patterns fabricated in a resist on a Si substrate treated with TMSP or HMDS for 30 sec. at lOO C. Figure 9 shows 0.3 pi m line-and-space patterns fabricated in the resist on a TiN substrate. For TMSP, as same as for HMDS, hi aspect ratio and precise resist patterns were successfully achieved without any peeling off. 

Figure 6.7 SEM image of negative-tone line and space patterns for the resist film formulated with 44, reported in Reference [77] (Reproduced by permission of Wiley-VCFl Verlag GmbFl Co. KGaA. Copyright 2006. Reprinted from Reference [77]).

The 193 nm water-based immersion lithography is the only option for the next nodes. However, its resolution limit at a maximum practical NA of 1.35 is around 40 nm. In this situation, double patterning has emerged as the semiconductor industry s chosen method. In one form of double patterning known as litho-etch-litho-etch (LELE), features are printed at a relaxed pitch that is within the capabilities of 193 nm limitation lithography, e.g., line and space patterns at a V3 critical dimension (CD) pitch ratio. Schematics... 

Fig. 15. Negative tone relief patterns formed in a covalent-type photosensitive polyamic ester film using the process shown in Figure 11. (a) Resolution test pattern showing 40 /rm features in a 40-/xm film, (b) Resolution of 5 p.m lines and space patterns in a 18-jum film. Courtesy of Arch Chemicals, Inc.

We fabricated an LC grating using a two-step exposure method with a line-and-space patterned photomask. The PLCP consisted of a methacrylate group with mesogenic 4-(4-methoxycinnamoyloxy)biphenyl side groups and nonmesogenic Wphenylmaleimide (PI). The chemical structure and synthesis procedure of PI was previously reported (Kawatsuki et al. 2004). PI has a nematic LC phase between 89 and 298 °C. Figure 9.1a shows the fabrication process and the structure... 

Figure 9 shows bi-level resist patterns obtained with TSPS/MP-1300 bi-level resist systems using electron-beam exposure. The TSPS functional groups are methyl and chloromethyl, and the eqiosure dose was 16 /u.C/cm. Using Oj-RIE, 0.1 jLim line-and-space patterns and 0.2 /Ltm space patterns can be transferred accurately to the bottom layer, without thermal deformation. Figure 10 shows 0.075 lira line-and-space patterns, obtained with TSPS/MP-1300 bi-level resist system, which are possible using the small partide size of TSPS. 

Figiure 17 shows bi-level resist patterns using the TSPS. A 0.2S /am line-and-space pattern and a 0.35 /am hole pattern can be delineated with TSPS/MP-1300 bi-level resist systems using a KrF-exdmer laser stepper. 

---