Organotin in Nonchemically Amplified Polymeric Hybrid Resist Imparts Better Resolution with Sensitivity for Next-Generation Lithography

Abstract

Given the need for a next-generation technology node in the area of integrated circuits (ICs), improvement in the properties of resist materials, particularly sensitivity (E D ), resolution, good etch resistance, and low line edge/width roughness (LER/LWR), has been highly desirable but also extremely challenging. Herein, we report a series of organic− inorganic hybrid nonchemically amplified copolymer resists (n-CARs) bearing radiation-sensitive sulfonium functionality as well as tin metal as an organometallic unit in the structural backbone for low E D and LER/LWR. These resists have been synthesized by the free radical copolymerization of the organic monomer (4-(methacryloyloxy)phenyl)-dimethylsulfoniumtriflate (MAPDST) and acetyldibutylstannyl methacrylate (ADSM) in different feed ratios (97:3, 93:7, 88:12) and characterized using FT-IR, 1 H, 19 F NMR, GPC, XPS, and ICP-OES techniques. These MAPDST-co-ADSM copolymers exhibited molecular weights (M w ) in the range of 10 077−12 187 g mol −1 . Electron beam lithography (EBL) studies revealed that the negative tone n-CARs characteristic with patterning down to sub-15 nm features. The well-developed sub-15 nm nanofeatures showed low LER of ∼1.29 ± 0.07 line patterns (number belongs to feed ratio 93:7). The variable e-beam exposure dose study revealed that the E D of these resists varies with the percentage of incorporated Sn in the polymer matrix. Incorporation of 2.48 wt % Sn (feed ratio 88:12) in the polymer chain led to a significant enhancement in the E D (175 μC/cm 2 ). Furthermore, the mechanistic study of pattern development has been performed with electron beam reactivity analyses using the XPS technique. These investigations substantiate the potential candidature of developed resist formulation for next-generation semiconductor technology applications.

Molecular Glass Resists Based on Tetraphenylsilane Derivatives: Effect of Protecting Ratios on Advanced Lithography

“…As predicted by Moore’s Law, the density of integrated circuits (ICs) has been improved exponentially for high-performance semiconductor devices and the photolithographic fabrication of nanoscale semiconductor devices requires increasingly high-resolution techniques. , Extreme ultraviolet lithography (EUVL) and electron beam lithography (EBL) are key advanced lithographic technologies for the production of feature sizes lower than 20 nm. − As the feature size decreases, the requirements for resists’ performance have gradually increased. It is still a great challenge to develop resist materials fulfilling all the requirements for advanced lithography such as high resolution (R) and sensitivity (S), low line edge roughness (LER), high etching resistance, and low outgassing. − The traditional polymeric materials are unfavorable for achieving high-resolution lithographic patterns with low LER due to their characteristics, such as polydispersity, large molecular size, chain entanglement, and poor compatibility with photoacid generators (PAGs). − …”

A novel dual-tone molecular glass resist based on adamantane derivatives for electron beam lithography

“…2,3,[16][17][18][19][20] Gonsalves et al designed a nonchemically amplified polymeric hybrid resist based on the radiation-sensitive sulfonium functionality and organotin. 21 25 nm half-pitch patterns can be obtained at a dose of 400 mC cm À2 with a 20 kV acceleration voltage. Besides, metalcontaining cluster resists are capable of forming sub-25 nm patterns by using EBL.…”

Functionalized Ag Nanoparticles Embedded in Polymer Resists for High-Resolution Lithography

“…35 In this regard, insertion of high-atomic-number nanomaterials in the resist formulation plays a significant role in high-speed lithography applications. 22,36 Also, the irradiation absorption cross sections (σ) of metal nanoparticles (such as Au, Ag, and Sn) are considerably greater than that of carbon or oxygen in resists, which eventually enhances the resist sensitivity. 37,38 Thus, the amalgamation of high-atomic-number metal nanoparticles in the polymer matrix may lead to the development of resists with better mechanical and chemical properties, high sensitivity, low line edge roughness/line width roughness (LER/LWR), and low CD through the enhanced absorption of exposure radiation.…”

“…In this progress, Nandi et al has produced high-aspect-ratio patterns of 100 nm with an ionic photoacid generator-included Terpolymer photoresist, viz., GBLMA–MAMA–MAPDST . Apart from CARs, hybrid resists are also being considered as emerging candidates for current lithography technology mainly due to their patterning potential for high-resolution features in the absence of PAGs in resist compositions. − Similarly, metal–organic clusters and methacrylate-based materials without any PAG have also been reported with notable sensitivity toward all types of irradiations. − Recently, our group developed nickel-based negative tone resists using EBL/HIBL and showed sub-10 nm line patterning. , Also, the negative tone chromium-containing resists revealed the patterning capability and high-etch resistance to silicon and tungsten at sub-10 nm resolution …”

“…Hence, the sensitivity of the resist can be improved through the incorporation of a high irradiation absorber entity in the resist formulation . In this regard, insertion of high-atomic-number nanomaterials in the resist formulation plays a significant role in high-speed lithography applications. , Also, the irradiation absorption cross sections (σ) of metal nanoparticles (such as Au, Ag, and Sn) are considerably greater than that of carbon or oxygen in resists, which eventually enhances the resist sensitivity. , Thus, the amalgamation of high-atomic-number metal nanoparticles in the polymer matrix may lead to the development of resists with better mechanical and chemical properties, high sensitivity, low line edge roughness/line width roughness (LER/LWR), and low CD through the enhanced absorption of exposure radiation. , Silver nanostructures that have been embedded in the polymer matrix were reported widely in the literature. , In this regard, silver nanoparticles were embedded in the SU8 photoresist that creates a conductive photoresist with various structures . Recently, the silver salt solution was mixed with the S1805 Novolac-based positive tone photoresist and exposed in EBL to develop features of 10 μm .…”