Pure thin films of organotin compounds have been lithographically evaluated using extreme ultraviolet lithography (EUVL, 13.5 nm). Twenty compounds of the type R 2 SnðO 2 CR 0 Þ 2 were spin-coated from solutions in toluene, exposed to EUV light, and developed in organic solvents. Exposures produced negative-tone contrast curves and dense-line patterns using interference lithography. Contrast-curve studies indicated that the photosensitivity is linearly related to the molecular weight of the carboxylate group bound to tin. Additionally, photosensitivity was found to be linearly related to free radical stability of the hydrocarbon group bound directly to tin (R ¼ phenyl, butyl, and benzyl). Dense-line patterning capabilities varied, but two resists in particular show exceptionally good line edge roughness (LER). A resist composed of an amorphous film of ðC 6 H 5 CH 2 Þ 2 SnðO 2 CCðCH 3 Þ 3 Þ 2 (1) achieved 1.4 nm LER at 22-nm half-pitch patterning and a resist composed of ðC 6 H 5 CH 2 Þ 2 SnðO 2 CC 6 H 5 Þ 2 (2) achieved 1.1 nm LER at 35-nm half-pitch at high exposure doses (600 mJ∕cm 2 ). Two photoresists that use olefin-based carboxylates, ðC 6 H 5 CH 2 Þ 2 SnðO 2 CCH═CH 2 Þ 2 (3) and ðC 6 H 5 CH 2 Þ 2 SnðO 2 CCðCH 3 Þ═CH 2 Þ 2 (4), demonstrated better photospeeds (5 mJ∕cm 2 and 27 mJ∕cm 2 ) but worse LER.

We have developed organometallic carboxylate compounds [R n M(O 2 CR') 2 ] capable of acting as negativetone EUV resists. Overall, the best and fastest resists contain antimony, are pentavalent and the carboxylate group contains a polymerizable olefin (e.g. acrylate, methacrylate or styrenecarboxylate). Evidence suggests that high sensitivity is achieved through the polymerization of olefins in the exposed region. We have performed a systematic sensitivity study of molecules of the type R n M(O 2 CR') 2 where we have studied seven R groups, four main group metals (M), and three polymerizable carboxylate groups (O 2 CR'). We found that the greatest predictor of sensitivity of the R n Sb(O 2 CR') 2 resists is their level of polymerizable olefins. We mathematically define the polymerizable olefin loading (POL) as the ratio of the number of olefins vs. the number of non-hydrogen atoms. Linear and log plots of E max vs. POL for a variety of molecules of the type R 3 Sb(O 2 CR') 2 lend insight into the behaviour of these resists.

We have developed organometallic carboxylate compounds [R n MðO 2 CR 0 Þ 2 ] capable of acting as negative-tone extreme ultraviolet (EUV) resists. The most sensitive of these resists contain antimony, three R-groups and two carboxylate groups, and carboxylate groups with polymerizable olefins (e.g., acrylate, methacrylate, or styrenecarboxylate). Evidence suggests that high sensitivity is achieved through the polymerization of olefins in the exposed region. We have performed a systematic sensitivity study of the molecules of the type R n MðO 2 CR 0 Þ 2 where we have studied seven R groups, four main group metals (M), and three polymerizable carboxylate groups (O 2 CR 0). The sensitivity of these resists was evaluated using E max or dose to maximum resist thickness after exposure and development. We found that the greatest predictor of sensitivity of the R n SbðO 2 CR 0 Þ 2 resists is their level of polymerizable olefins. We mathematically define the polymerizable olefin loading (POL) as the ratio of the number of olefins versus the number of nonhydrogen atoms. Linear and log plots of E max versus POL for a variety of molecules of the type R 3 SbðO 2 CR 0 Þ 2 lend insight into the behavior of these resists.

We present the synthesis and preliminary lithographic evaluation of Molecular Organometallic Resists for EUV (MORE) that contain post-transition metals. These elements have high EUV optical density so they can utilize a large fraction of the incident photons. We will describe two technical approaches for EUV resist platforms that contain bismuth. Approach 1: Combination of organometallic compounds with photoacid generators. Approach 2: Combination of high-oxidation state metal-center oligomers that utilize carboxylate anions bound to the metal centers.

Abstract. Here, we present platinum and palladium mononuclear complexes with EUV photosensitivity and lithographic performance. Many platinum and palladium complexes show little or no EUV sensitivity; however, we have found that metal carbonates and metal oxalates (L 2 MðCO 3 Þ and L 2 MðC 2 O 4 Þ; M ¼ Pt or Pd) are sensitive to EUV. The metal carbonates give negative-tone behavior. The most interesting result is that the metal oxalates give the first positive-tone EUV resists based on mononuclear organometallic compounds. In particular, (dppm)Pd(C 2 O 4 ) (dppm ¼ 1,1-bis(diphenylphosphino)methane) (23) prints 30-nm dense lines with E size of 50 mJ∕cm 2 . Derivatives of (23) were synthesized to explore the relationship between the core metal and the resist sensitivity. The study showed that palladium-based resists are more sensitive than platinum-based resists. The photoreaction has been investigated for two of our most promising resists, ðdppmÞPdðC 2 O 4 Þ (23) and ðPh 2 EtPÞ 2 PdC 2 O 4 (27). Our experiments suggest the loss of CO 2 and the formation of a zerovalent L 4 Pd complex upon exposure to light. We have identified dppm 2 PdðδðPÞ23:6Þ as the main photoproduct for (23) and ðPh 2 EtPÞ 4 Pd (δðPÞ32:7) as the main photoproduct for (27).