A Transparent Photoresist Made of Titanium Dioxide Nanoparticle-Embedded Acrylic Resin with a Tunable Refractive Index for UV-Imprint Lithography

Transparent photoresists with a high refractive index(RI)and high transmittance in visible wavelengths have promising functionalities in optical fields.This work reports a kind of tunable optical material composed of titanium dioxide nanoparticles embedded in acrylic resin with a high RI for ultraviolet(UV)-imprint lithography.The hybrid film exhibits a tunable RI of up to 1.67(589 nm)after being cured by UV light,while maintaining both a high transparency of over 98%in the visible light range and a low haze of less than 0.05%.The precision machining of optical microstructures can be imprinted easily and efficiently using the hybrid resin,which acts as a light guide plate(LGP)to guide the light from the side to the top in order to conserve the energy of the display device.These preliminary studies based on both laboratory and commercial experiments pave the way for exploiting the unparalleled optical properties of nanocomposite resins and promoting their industrial application.

Latest developments in EUV photoresist evaluation capability at Shanghai Synchrotron Radiation Facility

Evaluating the comprehensive characteristics of extreme ultraviolet(EUV)photoresists is crucial for their application in EUV lithography,a key process in modern technology.This paper highlights the capabilities of the Shanghai Synchrotron Radiation Facility(SSRF)08U1B beamline in advancing this field.Specifically,it demonstrates how this beamline can create fringe patterns with a 15-nm half-pitch on a resist using synchrotron-based EUV lithography.This achievement is vital for evaluating EUV photoresists at the advanced 5-nm node.We provide a detailed introduction to the methods and experimental setup used at the SSRF 08U1B beamline to assess an EUV photoresist.A significant part of this research involved the fabrication of high-resolution hydrogen silsesquioxane mask gratings.These gratings,with an aspect ratio of approximately 3,were created using electron beam lithography on an innovative mask framework.This framework was crucial in eliminating the impact of zeroth-order light on interference patterns.The proposed framework propose offers a new approach to mask fabrication,particularly beneficial for achromatic Talbot lithography and multicoherent-beam interference applications.

Synthesis and Properties of UV-curable Hyperbranched Polyurethane and Its Application in the Negative-type Photoresist

UV-curable hyperbranched polyurethane （UV-HBPU） containing carboxyl groups was synthesized from isophorone diisocyanate （IPDI）, diethanolamine （DEOA）, polyethylene glycol （PEG-400）, hydroxyethyl acrylate （HEA）, and 2,2-his （hydroxymethyl） propionic acid （DMPA）. The UV-HBPU was used as a negative-type photoresist for a printed circuit board （PCB）. Fourier-transform infrared spectroscopy （FTIR） and proton nuclear magnetic resonance （1HNMR） spectroscopy of UV-HBPUs indicated that the synthesis was successful. Differential scanning calorimetry （DSC） and thermogravimetric analysis （TGA） showed that the thermal stability of the UV-HBPUs decreased as the HEA content increased. The polymer exhibited excellent photoresist properties, and the resolution of circuits based on this negative-type photoresist reached 10 μm.

Simulations of Ion Behaviors in a Photoresist Trench During Plasma Etching Driven by a Radio-Frequency Source

Ion＇s behavior plays an important role in plasma etching processes and is determined by the local electric potential in the etched trenches. In this study, with the trench powered by a radio frequency （rf） source, the Laplace equation is solved to obtain the electric potential. The ion trajectories and the ion energy distribution （IED） at the bottom of the trench are obtained self-consistently by tracking the ions in the trench. The results show that the aspect ratio of depth- to-width of the photoresist trench and the voltage amplitude of the rf source applied to the electrode are important parameters. The larger the aspect ratio and the smaller the amplitude are, the more ions hit the sidewalls, which results in a notching phenomenon. Meanwhile, there are a higher high-energy peak and a lower low-energy peak in the IED with the increase in aspect ratio.

Recent Advances in Organic-inorganic Hybrid Photoresists

Photoresists are radiation-sensitive materials used for forming patterns to build up IC devices.To date,most photoresists have been based on organic polymers,which have been dominating the semiconductor industries over the past few decades.It is obvious that extreme ultraviolet(EUV)lithography has become the next-generation lithography technology.The development of comprehensive performance EUV resist is one of the most critical issues.However,organic polymeric photoresists are difficult to meet the harsh requirements of EUV lithography.Pure inorganic photoresists such as metal salts,hydrogen silsesquioxane(HSQ)are expected for EUV lithography due to their high resistance and high resolution.But the low sensitivity makes them not suitable for high volume manufacturing(HVM).Organic-inorganic hybrid photoresists,containing both organic and inorganic components,are regarded as one of the most promising EUV resists.They combine both merits of organic and inorganic materials and have significant advantages in machinability,etching resistance,EUV absorption,and chemical/thermal stability.Organic-inorganic hybrid photoresists are considered as ideal materials for realizing industrialgrade patterns below 10 nm.This review mainly focuses on the development of organic-inorganic hybrid photoresists over the past decade.

Acidic Polyester Imides as Thermally Stable Binder Polymers for Negative-Tone Black Photoresist

Polyimides are well-known for their high chemical inertness and thermal stability. However, it is usually challenging to synthesize UV-curable polyimides since the imidization reaction requires such harsh conditions that acrylate type double bonds cannot withstand. In this work, synthetic methods are developed to obtain polyester-imide type binder polymers with high thermal stability, high compatibility with the other components of the black photoresist, and fine photolithographic patterning property for the negative-tone black photoresist. The syntheses of diimide-diacid or diimide-diol intermediates for the polyesterification with dianhydride gave polyester imides which meets this requirement. The photolithographic tests have shown that the patterning of the micron-sized PDL of the organic light emitting diode (OLED) panel could be obtained. This work will interest the researchers working on the design and optimization of thermally stable binder polymers.

COPOLYMERS OF CHLOROETHYL METHACRYLATE, GLYCIDYL METHACRYLATE, AND METHYL METHACRYLATE AS SYNCHROTRON RADIATION x-RAY PHOTORESISTS

The copolymers of chloroethyl methacrylate (CMA), glycidyl methacrylate (GMA), and methyl methacrylate (MMA) were synthesized in benzene solution. Their breadths of the molecular weight distributions are 2.1 and 2.3, respectively. The thermal stability of P(GMA-CMA) is superior to that of P(CMA-MMA). The resolutions of P(CMA-MMA) and P(GMA-CMA) photoresists were found to be 0.1-0.16 mu m and 0.17-0.2 mu m, respectively. (Author abstract) 9 Refs.

Optimum design of photoresist thickness for 90-nm critical dimension based on ArF laser lithography

In this work, a 90-nm critical dimension （CD） technological process in an ArF laser lithography system is simulated, and the swing curves of the CD linewidth changing with photoresist thickness are obtained in the absence and presence of bottom antireflection coating （BARC）. By analysing the simulation result, it can be found that in the absence of BARC the CD swing curve effect is much bigger than that in the presence of BARC. So, the BARC should be needed for the 90-nm CD manufacture. The optimum resist thickness for 90-nm CD in the presence of BARC is obtained, and the optimizing process in this work can be used for reference in practice.

Fabrication of Diffraction-limited Full Aperture Microlens Array by Melting Photoresist

A further study on the fabrication of diffraction--limited full aperture microlens array by melting photoresist is described. The formation of aspherical surface is considered. The parameters for controlling the process of lens production, the height of original photoresist cylinders and the angle of contact between the melted photoresist and the substrate, are discussed in detail. The diffraction limited full--aperture microlens arrays have been obtained,and some measurement results are shown in the paper. A method of controlling the formation of quality microlens array in real time is suggested.

Epoxy Methacrylate Resin as Binder Polymer for Black Negative-Tone Photoresists

Epoxy acrylate (EA) resin, which originates from epoxides, has long been served as a photocurable coating and adhesive material owing to its double bonds. Specifically, alkaline-developable EA resins can be used as a binder polymer in negative-tone photoresists. In this work, we synthesized a series of acidic polyester-type epoxy methacrylate resins, characterized the intermediates and products, and tested their performance as a binder polymer for the photolithographic micro-patterning of the pixel-defining layer on organic light-emitting diodes in comparison to a widely used commercial binder polymer. Copolymer-type binder polymer BP-2-2 was produced excellent patterning with no residue due to its high compatibility with the black mill base.

Balancing sensitivity and resolution by feedback regulation of free radicals from Sn-C bonds in tin-oxygen clusters EBL photoresist

Notably,the cleavage of Sn–C bonds in extreme-ultraviolet photoresists containing Sn-oxygen(oxo)clusters and the generation of free radicals upon exposure lead to the chemical linking of Sn-oxo cores and subsequent solubility shifts.The reactivities and migration patterns of the generated radicals substantially influence patterning outcomes,including sensitivity and resolution.Herein,two Snoxo clusters,Sn_(4)-Me-C_(10)(with Sn–methyl)and Sn_(4)-Bu-C_(10)(with Sn–butyl),were combined to balance the sensitivity and resolution of photoresists,leveraging the feedback regulation between methyl and butyl free radicals generated from Sn–C bond cleavage.During electron beam lithography exposure,sensitive butyl radicals produced by Sn_(4)-Bu-C_(10)initiated reactions within Sn_(4)-Me-C_(10),improving sensitivity.Subsequently,the unstable methyl and bulky adamantyl radicals generated by Sn_(4)-Me-C_(10)quenched the excess butyl radicals,thus improving the resolution and exposure latitude.Thus,this method leveraging the feedback regulation of free radicals offers new insights into the design of sensitive metal oxide resists with enhanced resolution.

Heterometallic Ti-Zr oxo nanocluster photoresists for advanced lithography

Extreme ultraviolet lithography(EUVL)and electron beam lithography(EBL)are considered to be crucial lithography techniques utilized in the fabrication of nanoscale semiconductor devices.However,the industry currently faces a scarcity of EUV photoresists that meet the increasingly challenging standards in terms of resolution,sensitivity and roughness.Metal oxo nanoclusters have garnered significant interest in the field of EUV photoresist due to their relatively stronger absorption cross-section for extreme ultraviolet light and lower dimensions.In this study,we utilize a heterometallic nanocluster strategy by a combination of titanium and zirconium metals to investigate their solubility,assess the suitability of various developers,and evaluate their performance in electron-beam and EUVL,as well as study their etch resistance for pattern transfer.We demonstrate that R-4 is able to get a critical dimension(CD)of 25 nm at low doses under EBL,as well as 50 nm resolution at EUVL with a remarkable sensitivity of 19.7 mJ cm−2.This study offers an efficient heterometallic method for optimizing the lithographic performance of metal oxo nanocluster photoresists,which can benefit the development of commercially viable next-generation EUV photoresists.

Effect of Free Radicals on Irradiation Chemistry of a Double-Coordination Organotin(Sn_(4))Photoresist by Adjusting Alkyl Ligands

Metal oxide cluster(MOC)photoresists are highly promising materials for the next generation of extreme ultraviolet lithography(EUVL).The consecutive exploration of novel MOC materials and their structural irradiation chemistry are the major concerns associated with EUVL.Herein,we report two bicoordinated tin-oxo clusters(TOCs),the organic ligands of which contain both adamantane carboxylic acids and alkyl groups(methyl:Sn_(4)–Me–C10;butyl:Sn_(4)–Bu–C10).We explore the correlation between the structures of the TOCs and their patterning properties by adjusting the alkyl groups coordinated to the Sn atom.The structural variation causes different irradiation chemistry,with Sn_(4)–Me–C10 exhibiting improved resolution and Sn_(4)–Bu–C10 demonstrating higher sensitivity.These differences are attributed to the bonding energies of the Sn-methyl and Sn-butyl groups,the size of the resulting alkyl radicals,and their reaction probabilities.Both clusters occur in the reactions of Sn–C bond cleavage and the decarboxylation of adamantane carboxylic acids upon irradiation.However,the entire process exhibits distinct characteristics.Based on the electron-beam lithography and other experiments,we proposed irradiationinduced reaction mechanisms for both clusters.The Sn_(4)–Bu–C10 cluster predominantly undergoes alkane chain linkage,whereas the Sn_(4)–Me–C10 cluster mainly follows the adamantanes linkage pathway.

基于论文和专利分析的光刻胶技术发展态势研究

作为半导体芯片、显示屏等制造工艺中重要的上游必备材料,光刻胶技术发展至关重要。基于文献计量研究方法探究光刻胶技术的现状及趋势发现,2003—2012年为日本重点企业光刻胶技术相关专利的申请高峰期,2013年后开始放缓,2017年以后下降明显。从专利技术分析看,日本重点企业近10年在光敏树脂组成与光阻层、薄膜材料、可溶性树脂与含碱材料、正性光刻胶以及复合物等方面持续布局。近5年则在光刻胶图案、掩膜版、固体滤光片和剥离剂等方面加强了布局。从论文分析看,基础技术研究主要围绕光刻胶新型材料、性能提升、加工技术创新以及高精度制造等方面。

具有双重显影特性的多用途单分子树脂化学放大光刻胶

化学放大光刻胶(CARs)由于其在分辨率和灵敏度方面的出色性能而广泛应用于光刻领域。本文报道了一种基于单分子树脂的多用途化学放大光刻胶SP8-PAG_(AN),可同时用于365 nm光刻和电子束光刻。该体系主要由螺二芴结构的单分子树脂主体材料(SP-8Boc)和N-(三氟甲基磺酸酯基)蒽-1,9-二羧酰亚胺非离子型光致产酸剂(PAGAn)组成。测试了产酸剂PAGAN在365 nm紫外光激发下的光致产酸效率ΦH+为23%。研究了SP8-PAG_(AN)光刻胶的365 nm光刻和电子束光刻性能。365 nm光刻中,分别利用四甲基氢氧化胺(TMAH,质量分数2.38%)水溶液和正己烷作为显影液,可实现1μm正性和负性光刻图案。电子束光刻中,可实现50 nm Line/Space(L/S)的正性密集线条图案(曝光剂量110μC/cm^(2)),32 nm L/S的负性密集线条图案(曝光剂量40μC/cm^(2))以及19 nm L/3S负性半密集线条图案(曝光剂量96μC/cm^(2))。本研究工作提供了一种具有双重显影特性的多用途单分子树脂化学放大光刻胶的新范例。

新型锑氧簇光刻胶的性能与机理研究

随着半导体行业集成度越来越高,对光刻材料提出了更高的要求。近年来,金属氧簇光刻胶由于尺寸小、结构设计灵活,得到了广泛的研究。目前锑基金属光刻胶仅局限于含锑配合物。开发出新型锑氧簇光刻胶,通过对比金属有机组装Sb_(4)O-1与自组装Sb_(4)O-2的溶解度差异说明自组装策略优势。原子力显微镜证实Sb_(4)O-2光刻胶可形成光滑薄膜,并获得低粗糙度值(均方根粗糙度<0.3 nm)。电子束光刻(EBL)证明Sb_(4)O-2光刻胶优异的图案化能力(线宽<50 nm),理论计算支持X射线光电子能谱(XPS)分析的新型自组装Sb_(4)O-2“配体解离”机制。

Electrochemical micromachining of micro-dimple arrays on cylindrical inner surfaces using a dry-film photoresist

The application of surface textures has been employed to improve the tribological performance of various mechanical components. Various techniques have been used for the application of surface textures such as micro-dimple arrays, but the fabrication of such arrays on cylindrical inner surfaces remains a challenge. In this study, a dry-film photoresist is used as a mask during through-mask electrochemical micromachining to successfully prepare micro-dimple arrays with dimples 94 lm in diameter and 22.7 lm deep on cylindrical inner surfaces, with a machining time of 9 s and an applied voltage of 8 V. The versatility of this method is demonstrated, as are its potential low cost and high efficiency. It is also shown that for a fixed dimple depth, a smaller dimple diameter can be obtained using a combination of lower current density and longer machining time in a passivating sodium nitrate electrolyte.

Full-color micro-LED display with high color stability using semipolar(20-21) InGaN LEDs and quantum-dot photoresist

Red-green-blue(RGB)full-color micro light-emitting diodes(μ-LEDs)fabricated from semipolar(20-21)wafers,with a quantum-dot photoresist color-conversion layer,were demonstrated.The semipolar(20-21)In Ga N/Ga Nμ-LEDs were fabricated on large(4 in.)patterned sapphire substrates by orientation-controlled epitaxy.The semipolarμ-LEDs showed a 3.2 nm peak wavelength shift and a 14.7%efficiency droop under 200 A∕cm2injected current density,indicating significant amelioration of the quantum-confined Stark effect.Because of the semipolarμ-LEDs’emission-wavelength stability,the RGB pixel showed little color shift with current density and achieved a wide color gamut(114.4%NTSC space and 85.4%Rec.2020).

Lateral bipolar photoresistance effect in the CIGS heterojunction and its application in position sensitive detector and memory device

Cu(In,Ga)Se2(CIGS) based multilayer heterojunction, as one of the best high efficiency thin film solar cells, has attracted great interest due to its outstanding features. However, the present studies are primarily focused on the structure optimization and modulation in order to enhance the photoelectric conversion efficiency. Here, we exploit another application of this multilayer heterostructure in photoresistance-modulated position sensitive detector by introducing lateral photoresistance effect.The lateral photoresistance measurements show that this multilayer heterojunction exhibits a wide spectral response(~330 to ~1150 nm) and excellent bipolar photoresistance performances(position sensitivity of ~63.26 X/mm and nonlinearity <4.5%), and a fast response speed(rise and fall time of ~14.46 and^14.42 ms, respectively). More importantly, based on the lateral photoresistance effect, the CIGS heterostructure may also be developed as a position-dependent resistance memory device, which can be modulated by changing laser intensity, wavelength, and bias voltage with excellent stability and repeatability, and the position resolution reaches up to 1 lm. These results can be well explained by considering the diffusion and the drift model of carriers in the CIGS multilayer heterojunction. This work provides a new approach of achieving novel photoelectric sensors and memory devices based on the traditional photovoltaic heterostructures.

光刻胶废剥离液中分离回收水和有机溶剂研究进展

光刻胶废剥离液中含有大量的水和有机溶剂,其中包含大量有回收价值的成分。从光刻胶废剥离液中回收水和有机溶剂可以减少对自然界的污染,实现资源化利用。综述了国内外几种从光刻胶废剥离液中回收水和有机溶剂常见分离方法及分离装置,并对不同情况下所产生效果进行分析比较。希望能为我国电子行业中光刻胶废剥离液的资源化处理提供借鉴。