US 10,754,248 B2  148  147  TABLE 6-continued  PEB  Eop  EL  Resist  (" C.)  (mJ/cm 2 )  (%)  Comparative  R-18  85  31  9.6  Example 2-6  Comparative  R-19  85  25  9.0  Example 2-7  Comparative  R-20  85  26  8.9  Example 2-8  CDU  MEF  (nm)  3.5  4.2  4.0  4.6  3.9  4.8  The results in Table 6 found the resist composition of the  present invention demonstrates favorable lithography per› formance such as EL, MEF, and CDU in hole patterning by  organic solvent development.  The resist compositions of the present invention (R-1 to  12) prepared by the compositions according to the above  Tables 4 and 5 and resist compositions (R-13 to 20) for  Comparative Examples were spin-coated on a substrate for  try layer process obtained by coating a spin-on carbon film  ODL-101 (Product from Shin-Etsu Chemical Co., Ltd.) 200  nm in thickness, and a silicon-containing spin-on hard mask  SHB-A940 (silicon content: 43% by mass) 35 nm in thick› ness thereon, and baked at 100°  C. for 60 seconds using a hot  plate to form a resist film 100 nm in thickness.  The product was subjected to pattern exposure using ArF  immersion excimer laser scanner (Product from Nikon Cor› poration, NSR-610C, NAl.30, a0.98/0.78, 4/5 annular illu› mination), and a 6% halftone phase shift mask with a pitch  of 100 nm a line width of 50 nm (on-wafer size) for  post-exposure 60-second heat treatment (post-exposure bak› ing: PEB). Thereafter, butyl acetate was discharged from a  development nozzle by rotation for 3 seconds at 30 rpm and  subjected to stationary puddle development for 27 seconds.  Consequently, line and space pattern (LS pattern) where a  non-exposed area protected from light by a mask is dis› solved into a developer to cause image inversion was  obtained with a space width of 50 nm and a pitch of 100 nm.  The obtained LS pattern was observed with electron  microscope, and the optimum exposure dose (Eop, mJ/cm 2 )  for obtaining a LS pattern with a space width of 50 nm and  a pitch of 100 nm was determined.  In exposure latitude evaluation, the exposure latitude  (unit: %) was determined from exposure dose which pro› vided a LS pattern with a hole diameter of 50 nm–l 0% ( 45  nm to 55 nm), according to the following formula.  [Sensitivity Evaluation]  [Exposure Latitude (EL) Evaluation]  [Examples 3-1 to 3-12, Comparative Examples 3-1  to 3-8] NTD; ArF Exposure Patterning Evaluation  (2); Line and Space Evaluation  Exposure latitude (%)~(1El-E21/Eop)x100  space width, MEF values were determined according to the  following formula. The performance is favorable as the  value approaches 1.  b: constant  The number of defects in a pattern formed after develop› ment was examined by a defect inspection system KLA2800  (Product from KLA-Tencor) to determine the defect density  according to the following formula.  [Line Width Roughness (LWR) Evaluation]  [Defect Density Evaluation]  Defect density (number/cm $^{2}$)cc\otal number of  detected defects/inspected area  Formed pattern: 50 nm 1:1 line and space’s repeated pattern  Defect inspection conditions: light source  UV,  inspected  pixel size 0.28  µm, cell to cell mode  In this evaluation, "favorable" is under 0.05/cm 2 ,  and  "unfavorable" is 0.05/cm 2  or more.  Table 7 shows the results of the evaluations.  El: Optimum exposure dose providing LS pattern with a  space width of 45 nm and a pitch of 100 nm  E2: Optimum exposure dose providing LS pattern with a  space width of 55 nm and a pitch of 100 nm  Eop: Optimum exposure dose providing LS pattern with a  space width of 50 nm and a pitch of 100 nm  The mask pitch was fixed, and the mask line width was  changed, and the films were irradiated with the optimum  exposure dose in the above sensitivity evaluation to form  patterns. From the changes in mask line width and pattern  [Mask Error Factor (MEF) Evaluation]  The results in Table 7 found the resist composition of the  present invention demonstrates favorable lithography per› formance such as EL, MEF, and LWR in negative patterning  by organic solvent development, as well as effective defect  reduction.  It was thus found that the resist composition of  the present invention is effective in development process of  an organic solvent.  TABLE 7  Re- PEB  sist  (" C.)  Example 3-1  R-1  95  Example 3-2  R-2  95  Example 3-3  R-3  90  Example 3-4  R-4  90  Example 3-5  R-5  85  Example 3-6  R-6  85  Example 3-7  R-7  85  Example 3-8  R-8  90  Example 3-9  R-9  85  Example 3-10  R-10  95  Example 3-11  R-11  85  Example 3-12  R-12  85  Comparative  R-13  90  Example 3-1  Comparative  R-14  90  Example 3-2  Comparative  R-15  85  Example 3-3  Comparative  R-16  85  Example 3-4  Comparative  R-17  85  Example 3-5  Comparative  R-18  85  Example 3-6  Comparative  R-19  85  Example 3-7  Comparative  R-20  85  Example 3-8  Eop  (mJ/  cm 2 )  34  34  31  30  26  31  26  30  27  25  27  27  32  29  26  29  29  31  26  26  EL  (%)  13.2  13.3  12.9  12.5  13.8  13.5  13.2  13.0  13.1  13.8  13.7  13.5  10.8  10.6  10.4  11.0  10.8  10.3  10.2  9.9  Defect  Density  LWR (number/  MEF  (nm) cm 2 )  4.4  3.7  3.4  3.6  3.5  3.7  3.7  4.3  4.4  4.3  3.6  3.8  4.5  4.7  5.0  4.8  4.4  4.4  5.0  4.9  3.9  3.8  3.8  3.7  3.9  3.7  3.9  3.6  3.5  3.5  3.7  3.8  4.5  4.6  4.7  4.6  4.5  4.8  4.9  5.0  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  Favorable  unfavorable  MEF~(pattem space width/mask line width)-b  The LS pattern obtained by irradiating films with the  optimum exposure dose was subjected to dimensional mea› lO surement at 10 portions in the longitudinal direction of the  space width using TDSEM (S-9380, Product from Hitachi  High-Technologies Corporation). The resulting standard  deviation  (a)  was multiplied by three  (3a)  to be defined as  a LWR. As the  3a  value is small, a pattern with small  15  roughness and uniform space width can be obtained. 