Lithographic Performance Research Articles

Lithographic performance of ZEP520A and mr-PosEBR resists exposed by electron beam and extreme ultraviolet lithography

Pattern transfer by deep anisotropic etch is a well-established technique for fabrication of nanoscale devices and structures. For this technique to be effective, the resist material plays a key role and must have a high resolution, reasonable sensitivity, and high etch selectivity against the conventional silicon substrate or underlayer film. In this work, the lithographic performance of two high etch resistance materials was evaluated: ZEP520A (Nippon Zeon Co.) and mr-PosEBR (micro resist technology GmbH). Both materials are positive tone, polymer-based, and nonchemically amplified resists. Two exposure techniques were used: electron beam lithography (EBL) and extreme ultraviolet (EUV) lithography. These resists were originally designed for EBL patterning, where high quality patterning at sub-100 nm resolution was previously demonstrated. In the scope of this work, the authors also aim to validate their extendibility to EUV for high resolution and large area patterning. For this purpose, the same EBL process conditions were employed at EUV. The figures of merit, i.e., dose to clear, dose to size, and resolution, were obtained, and these results are discussed systematically. It was found that both materials are very fast at EUV (dose to clear lower than 12 mJ/cm2) and are capable of resolving dense lines/space arrays with a resolution of 25 nm half-pitch. The quality of patterns was also very good, and the sidewall roughness was below 6 nm. Interestingly, the general-purpose process used for EBL can be extended straightforwardly to EUV lithography with comparably high quality and yield. Our findings open new possibilities for lithographers who wish to devise novel fabrication schemes exploiting EUV for fabrication of nanostructures by deep etch pattern transfer.

Large area thermal nanoimprint below the glass transition temperature via small amplitude oscillatory shear forming

Small amplitude oscillatory shear forming is a technique that improves the performance of nanoimprint lithography by amplifying shear flow in narrow, squeezed geometries created during melt molding or glass forming of supported polymer films. To date, the technique has only been demonstrated for single micrometer-scale contacts representative of single features on wafer-scale nanoimprint stamps. In this work, we demonstrate scaling up of small amplitude shear forming to realize micrometer and nanometer feature patterning of thermoplastic polymer films over macroscopic centimetre square areas at temperatures in the vicinity of, and below the glass transition. By the use of a small amplitude (typically 5–10% the smallest pattern feature dimension) lateral oscillatory shear strain at a 10kHz frequency superposed during the normal motion of a nanoimprint mold, we are able to achieve high fidelity pattern replication in PMMA at temperatures as low as 35°C below its glass transition temperature. We further show that the technique is effective to pattern both bulk polymer surfaces and supported thin films, with samples as thick as 50μm and as films as thin as 40nm being successfully patterned. We demonstrate enhanced pattern fidelity using line-pattern imprint molds of 4μm pitch and 35nm relief, as well as an assortment of other geometries. For 800nm PMMA films, a 40% reduction in the residual layer thickness at 100°C was achieved by the addition of shear strain. No feature distortion is observed due to the oscillatory motion of the mold. The technique is particularly advantageous for large scale features and cavities, as well as high aspect ratio geometries, as the high speed lateral motion of the mold features acts to cyclically pump material into areas where stresses generated by the normal motion of the mold will not suffice.

Precise Protein Photolithography (P3): High Performance Biopatterning Using Silk Fibroin Light Chain as the Resist.

Precise patterning of biomaterials has widespread applications, including drug release, degradable implants, tissue engineering, and regenerative medicine. Patterning of protein‐based microstructures using UV‐photolithography has been demonstrated using protein as the resist material. The Achilles heel of existing protein‐based biophotoresists is the inevitable wide molecular weight distribution during the protein extraction/regeneration process, hindering their practical uses in the semiconductor industry where reliability and repeatability are paramount. A wafer‐scale high resolution patterning of bio‐microstructures using well‐defined silk fibroin light chain as the resist material is presented showing unprecedent performances. The lithographic and etching performance of silk fibroin light chain resists are evaluated systematically and the underlying mechanisms are thoroughly discussed. The micropatterned silk structures are tested as cellular substrates for the successful spatial guidance of fetal neural stems cells seeded on the patterned substrates. The enhanced patterning resolution, the improved etch resistance, and the inherent biocompatibility of such protein‐based photoresist provide new opportunities in fabricating large scale biocompatible functional microstructures.

Alkyltin Keggin Clusters Templated by Sodium

AbstractDodecameric (Sn12) and hexameric topologies dominate monoalkyltin–oxo cluster chemistry. Their condensation, triggered by radiation exposure, recently produced unprecedented patterning performance in EUV lithography. A new cluster topology was crystallized from industrial n‐BuSnOOH, and additional characterization techniques indicate other clusters are present. Single‐crystal X‐ray analysis reveals a β‐Keggin cluster, which is known but less common than other Keggin isomers in polyoxometalate and polyoxocation chemistry. The structure is formulated [NaO4(BuSn)12(OH)3(O)9(OCH3)12(Sn(H2O)2)] (β‐NaSn13). SAXS, NMR, and ESI MS differentiate β‐NaSn13, Sn12, and other clusters present in crude “n‐BuSnOOH” and highlight the role of Na as a template for alkyltin Keggin clusters. Unlike other alkyltin clusters that are cationic, β‐NaSn13 is neutral. Consequently, it stands as a unique model system, absent of counterions, to study the transformation of clusters to films and nanopatterns.

Alkyltin Keggin Clusters Templated by Sodium.

Dodecameric (Sn12 ) and hexameric topologies dominate monoalkyltin-oxo cluster chemistry. Their condensation, triggered by radiation exposure, recently produced unprecedented patterning performance in EUV lithography. A new cluster topology was crystallized from industrial n-BuSnOOH, and additional characterization techniques indicate other clusters are present. Single-crystal X-ray analysis reveals a β-Keggin cluster, which is known but less common than other Keggin isomers in polyoxometalate and polyoxocation chemistry. The structure is formulated [NaO4 (BuSn)12 (OH)3 (O)9 (OCH3 )12 (Sn(H2 O)2 )] (β-NaSn13 ). SAXS, NMR, and ESI MS differentiate β-NaSn13 , Sn12 , and other clusters present in crude "n-BuSnOOH" and highlight the role of Na as a template for alkyltin Keggin clusters. Unlike other alkyltin clusters that are cationic, β-NaSn13 is neutral. Consequently, it stands as a unique model system, absent of counterions, to study the transformation of clusters to films and nanopatterns.

Co and terpolymer reactivity ratios of chemically amplified resists

Resists are important multicomponent system require in microelectronic industry for fabrication of integrated circuit (IC) devices. The current high end IC (integrated circuit) technology node in manufacturing is 20 nm and looking toward 16 and 10 nm nodes to fulfil market demand. A series of chemically amplified resists (CARs) based on co and terpolymers of 4-hydroxystyrene (HOST), 2-ethyl-2-adamantyl methacrylate (EAMA) and/or a monomer-bound anionic photoacid generator (PAG) were prepared and characterized. Specifically, Triphenylsulfonium salt 4-(methacryloxy)-2,3,5,6-tetrafluorobenzenesulfonate (F4 PAG) was incorporated into the main chain to get PAG bound polymer microstructure.The aim of the study was to investigate interplay of individual monomers in co and terpolymer systems. This was achieved by understanding the reactivity ratios and monomer sequence distribution in the polymer. Analysis was conducted by using a software PROCOP version2.3. The co/terpolymer compositions were determined by quantitative 1H NMR spectra. The copolymer reactivity ratio of each monomer was determined with Fineman–Ross, Kelen–Tüdös, and nonlinear least-squares curve- fitting methods. It was observed that EAMA is not polymerizable under given reaction conditions and copolymerization of EAMA-PAG was also not possible. HOST-EAMA system yielded reactivity ratios near zero indicating that they form quasi alternating structures. HOST-PAG system yielded copolymers rich in PAG. On the basis of the reactivity ratios determined from the binary copolymers, Alfrey–Goldfinger equations were used to estimate the compositions of the terpolymers. In terpolymer system, where two monomers were non homopolymerizable, both PAG and EAMA competed to add up to the HOST radical. All six reactivity values were less then unity indicating preferred cross propagation of radicals. PAG was the most reactive monomer. Monomer sequence distribution of copolymer and terpolymer was established to get an idea of detailed microstructure of the chain. Copolymers confirmed 84% of dyads formation of each monomer while terpolymer analysis revealed dominance of HOST centered triads. In addition to this, kinetics of terpolymerization reaction was performed to validate the theory. Findings from the study can be used to tailor make CAR synthesis for optimum EUV (extreme ultraviolet) lithography performance.

Consecutive imprinting performance of large area UV nanoimprint lithography using Bi-layer soft stamps in ambient atmosphere

For UV nanoimprint lithography (UV-NIL) using polymer soft stamps, imprinting at ambient atmosphere brings additional challenges due to evaporated solvents and possible byproducts resulting from the interaction between the UV light, oxygen and the polymer-based material. Moreover, the Laplace pressure may impact differently on the capillary filling for both positive and negative patterns at atmospheric pressure compared to that in the vacuum. Twenty consecutive imprints using bi-layer Polydimethylsiloxane (PDMS), PDMS/toluene-diluted PDMS, PDMS/X-PDMS, PDMS/vvsPDMS stamps have been tracked and inspected. The imprinting employs a center-to-edge scheme in ambient atmosphere. The results show that high reusability and imprint uniformity can be achieved for at least twenty consecutive imprints using the pure PDMS (PDMS/PDMS) and PDMS/toluene-diluted PDMS. These stamps can overcome the challenges of the interaction between the UV light, oxygen and the polymer-based materials. The Laplace pressure under atmosphere does not hinder the resist filling for such consecutive imprints.

Low Temperature Curable PI/PBO for Advanced Packaging

Photo-definable polyimides (PI) and polybenzoxazoles (PBO) have been widely used as dielectrics for re-distribution layers in wafer level chip size packages (WL-CSP). These materials can simplify the manufacturing process and ensure high reliability owing to their good mechanical properties and high thermal stability. For next generation electronic components fabricated by utilizing advanced packaging technologies such as 3D-stacking using TSV, package-on-package, fan-out WL-CSP etc., the most important requirements for dielectric materials are high lithographic performance, high adhesion to Cu RDL, high chemical resistance and low temperature curability. In this paper, we will report on our novel low temperature (<200C) curable PBO and PI. A novel alkaline positive tone PBO was developed by re-designing key components of the formulation to enhance lithographic performance, Cu adhesion and chemical resistance. It was found that the new PBO material showed higher lithographic performance than conventional PBOs due to its high dissolution contrast and which resulted in a resolution of 2micron (L/S) with a 7μm cured thickness and 3micron (L/S) with a 15micron cured thickness, respectively. This material also produced strong Cu adhesion and high chemical resistance at curing temperatures <200C with no delamination from the Cu RDL being observed after a 168hr Pressure Cooker Test (PCT). Furthermore, the new formulation showed high TCT resistance due to its high elongation below 0C. In addition, a novel solvent negative tone PI was also developed by incorporating a cross-linker to accelerate low temperature curability as well a photo-initiator to improve lithographic properties. As a result, the novel PI when cured at 175C for 1hr showed high Cu adhesion after 168hr PCT as well as high film properties. The new PI also showed excellent lithographic properties with a resolution of 6micron (L/S). Furthermore, the low temperature curable PI and PBO materials were used as dielectrics to fabricate WL-CSPs for both chip and board level reliability testing. The test results indicated that both the novel PBO and PI showed excellent reliability after thermal cycling (TCT) due to the significant improvements made to Cu adhesion and chemical resistance. These materials are expected to be promising for next generation WLP applications. Details are described in the presentation.

In-situ synthesis of thiophene-based multifunctional polymeric networks with tunable conductivity and high photolithographic performance

Design of novel multifunctional polymeric materials combining electrically conducting properties with patterning capability is a significant challenge in materials science. Herein, we report on the synthesis of multifunctional interpenetrating polymer networks (IPN) by the in-situ oxidative polymerization of thiophene-based monomers with Cu(ClO4)2 inside a novolac-based photoresist. The resulting IPNs show conductivities up to 20 S/cm depending on the monomer properties. Among them, 3,3‴-Dihexyl-2,2’:5′,2’’:5″,2‴-quaterthiophene (DH4T) is chosen because it has the largest conjugation length and excellent solubility in organic solvents. Moreover, it renders a low percolation threshold and smooth surface morphology if compared with terthiophene (3T). FTIR and XPS spectroscopy confirm the DH4T polymerization by Cu(ClO4)2 and provide some insights about the doping level of the conducting polymer. We also propose a new photolithographic route based on the DH4T polymerization in novolac after pattern generation by oxidant sorption. This novel fabrication route leads to conducting IPNs with outstanding lithographic performance.

Pattern-generation and pattern-transfer for single-digit nano devices

Single-electron devices operating at room temperature require sub-5 nm quantum dots having tunnel junctions of comparable dimensions. Further development in nanoelectronics depends on the capability to generate mesoscopic structures and interfacing these with complementary metal–oxide–semiconductor devices in a single system. The authors employ a combination of two novel methods of fabricating room temperature silicon single-electron transistors (SETs), Fowler–Nordheim scanning probe lithography (F-N SPL) with active cantilevers and cryogenic reactive ion etching followed by pattern-dependent oxidation. The F-N SPL employs a low energy electron exposure of 5–10 nm thick high-resolution molecular resist (Calixarene) resulting in single nanodigit lithographic performance [Rangelow et al., Proc. SPIE 7637, 76370V (2010)]. The followed step of pattern transfer into silicon becomes very challenging because of the extremely low resist thickness, which limits the etching depth. The authors developed a computer simulation code to simulate the reactive ion etching at cryogenic temperatures (−120 °C). In this article, the authors present the alliance of all these technologies used for the manufacturing of SETs capable to operate at room temperatures.

Analysis of multi-e-beam lithography for cutting layers at 7-nm node

Technology node scaling to the 7-nm node, self-aligned quadruple patterning plus cutting/blocking is widely adopted as a lithography solution for critical line and space layers. The cutting/blocking process can be done by 193i or EUV lithography. Due to resolution requirements in both X/Y directions, 193i requires two or three exposures to accomplish the cutting/blocking process, and the overlay among the exposures must be controlled very tightly. EUV can accomplish cutting/blocking by one exposure. However, the extremely high cost of EUV tool and mask, together with not so high throughput, appears to suggest that EUV lithography is not a cost-effective solution. From both technical and cost perspectives, we explore the possibility of using multi-e-beam lithography as an alternative solution for 7-nm cutting/blocking layers. First, we analyze design rules, which define resolution and overlay requirements of the cutting/blocking patterns. Then we report the lithography performance data of our leading-edge multi-e-beam tool and compare them with the cutting/blocking requirements. Finally, we do the cost analysis. Our results indicate that multi-e-beam lithography has a cost per wafer per layer advantage if it can commit a resolution of 32-nm half pitch, an overlay of <2.8 nm, and a throughput of 5 to 10 wph.

Surface affinity role in graphoepitaxy of lamellar block copolymers

Overcoming the optical limitations of 193-nm immersion lithography can be achieved using directed self-assembly (DSA) of block-copolymers (BCPs) as a low-cost and versatile complementary technique. The goal of this paper is to investigate the potential of DSA to address line and space (L/S) high-resolution patterning by performing the density multiplication of lines with the graphoepitaxy approach. As surface affinity is a key parameter in self-assembly, three variations, or “flavors,” of DSA template affinity are investigated regarding several success criteria such as morphology control or defectivity. More precisely, both the methodology to register DSA defects and the impact of process parameters on defectivity are detailed. Using the 300-mm pilot line available in LETI and Arkema’s advanced materials, we investigate process optimization of DSA line/space patterning of a 38-nm period lamellar PS-b-PMMA BCP (L38). Our integration scheme is based on BCP self-assembly inside organic hard mask guiding patterns obtained using 193i-nm lithography. Defect analysis coupled with the fine tuning of process parameters (annealing, brush material) provided the optimum conditions for the L38 self-assembly. Using such conditions, DSA using the three affinity flavors is investigated by means of SEM top-view and cross-section review. Lithographic performances of one selected flavor are then evaluated with the comparison of process windows function of either commensurability, morphology, or roughness. This work is meant as a guideline for the graphoepitaxy optimization of materials and process parameters on a 300-mm platform.

Bubbling behaviors induced by gas-liquid mixture permeating through a porous medium

This paper investigates the bubbling behaviors induced by gas-liquid mixture permeating through porous medium (PM), which was observed in developing immersion lithography system and was found having great differences with traditional bubbling behaviors injected with only gas phase through the PM. An experimental setup was built up to investigate the bubbling characteristics affected by the mixed liquid phase. Both the flow regimes of gas-liquid mixture in micro-channel (upstream of the PM) and the bubbling flow regimes in water tank (downstream of the PM) were recorded synchronously by high-speed camera. The transitions between the flow regimes are governed by gas and liquid Weber numbers. Based on the image analysis, the characteristic parameters of bubbling region, including the diameter of bubbling area on PM surface, gas-phase volume flux, and dispersion angle of bubbles in suspending liquid, were studied under different proportions of gas and liquid flow rate. Corresponding empirical correlations were developed to describe and predict these parameters. Then, the pertinent bubble characteristics in different bubbling flow regimes were systematically investigated. Specifically, the bubble size distribution and the Sauter mean diameter affected by increasing liquid flow rate were studied, and the corresponding analysis was given based on the hydrodynamics of bubble-bubble and bubble-liquid interactions. According to dimensionless analysis, the general prediction equation of Sauter mean diameter under different operating conditions was proposed and confirmed by experimental data. The study of this paper is helpful to improve the collection performance of immersion lithography and aims to reveal the differences between the bubbling behaviors on PM caused by only gas flow and gas-liquid mixture flow, respectively, for the researches of fluid flow.

Flow behavior control in immersion lithography

Over the past decade, immersion lithography has been the primary technology for exposure process in semiconductor manufacturing. Compared with traditional dry lithography method, this technology improves the exposure resolution greatly by inserting a high index liquid into the gap between lens and wafer surface. Keeping the immersion liquid pure and uniform as well as avoiding residual droplets during high speed scanning motion are two challenges faced by the development of immersion lithography. Contaminations, particles, bubbles, heating and stress in the liquid will destroy the continuity of the refractive index. High speed motion of the wafer during scanning may break the meniscus stability on the interface between the liquid and the gas surrounding it, and then generate residual droplets on the wafer. All above phenomena will affect the exposure performance of immersion lithography and corresponding flow behavior control methods are required to solve the problems. This paper gives a review of the studies on flow behavior control in immersion lithography, which contains two parts: studies for liquid purity and uniformity and studies for meniscus stability. In each part, the mechanism and character of the flow behaviors as well as their effects to exposure performance are presented firstly. Then, control approaches adopted by now, including material and surface modifications as well as immersion head utilization, are introduced. In addition, the challenges faced in future studies are also pointed out. The purpose of this review paper is to help the researchers to understand the flow control problems in immersion lithography and to provide better control approaches for exposure performance improvement.

Chemically amplified molecular resists based on noria derivatives containing adamantyl ester groups for electron beam lithography

In this study, the authors examined the synthesis and resist performance of positive-tone chemically amplified molecular resist materials based on noria (water wheel in Latin) derivatives with pendant adamantyl ester (AD) groups (noria-AD) using an electron beam (EB) exposure tool. The physical properties of synthesized noria derivatives with various ratios of AD groups and their patterning properties were examined in an EB exposure tool. Furthermore, lithographic performances such as the etch durability and line width roughness of resist patterns were also investigated. These results showed that the physical properties and resist performance of the noria-AD were consistent with the ratio of AD groups, and noria derivatives have high potential to offer higher-resolution resist patterns for EB lithography.

Study of the electrode tool wear and the probe tip sharpening phenomena during the nanoscale STM electric discharge lithography of the bulk HOPG surface

Scanning tunneling microscope (STM)-based electric discharge lithography or machining is capable of fabricating nanostructures or nano-devices out of the carbon-based materials with low cost and high accuracy. As a tip-based nanofabrication method, the evolution of the STM probe tip, which functionalized as the electrode tool, is of great importance to the machining capability and performance of the STM electric discharge lithography. In this work, both the electrode tool wear (ETW) and the probe tip sharpening phenomena were investigated during the SPM electric discharge lithography of the bulk highly oriented pyrolytic graphite (HOPG) sample surface. The influence of the electrode tool wear evolution on the machining results was experimentally studied. The geometric parameters of the STM probe tip were measured from SEM imaging. Moreover, the probe tip sharpening phenomenon was specifically observed by applying the negative polarity machining. The evidences of the underlying mechanisms for the tip sharpening effect were revealed experimentally in this study, which have never been reported in the previous work. It is further proved that this effect could be utilized to the in-situ sharpening of the STM probe tip. Finally, the effective methods to improve the machining consistency and the tool lifetime were proposed.

Additive chemistry and distributions in photoresist thin films

The lithographic performance of thin photoresist films is a function of the distribution of formulation components, such as photoacid generator (PAG) molecules, and how these components undergo chemical modification and migrate within the film during the lithography processing steps. Argon gas cluster ion beam – secondary ion mass spectrometry depth profiles were used to monitor the PAG and quencher base distributions before and after exposure and postexposure bake processing steps for different photoresist formulations. PAG and quencher base distributions were correlated to depth of focus lithographic performance results.

Towards a novel positive tone resist mr-PosEBR for high resolution electron-beam lithography

Herein, we present the results of a systematic material development study we carried out in order to obtain a new positive tone resist for high resolution electron-beam lithography. Several acrylic copolymer materials with different mass fractions of the comonomers, different molecular weights and similar molecular weight distributions were synthesized and – as resist solutions – evaluated in terms of electron-beam lithography performance. On the one hand, within the ranges investigated, it was shown that the lithographic sensitivity is significantly influenced by the composition rather than by the molecular weight or molecular weight distribution. On the other hand, the etch resistance of the materials remains unaffected by changes of these parameters. The resist material exhibiting the best combination of the desired properties, mr-PosEBR, is 2 times more sensitive than PMMA (495kDa) and performs comparably to the known high resolution resist ZEP520A. For example, a grating pattern with 29nm wide lines with a period of 100nm could be generated in films of mr-PosEBR with an area dose of 100μC/cm2. In terms of resolution, single lines of only 35nm width could be fabricated via metal lift-off using 100kV EBL. Furthermore, the dry etch stability of mr-PosEBR in a reactive-ion etching (RIE) process (etch gases: CF4/SF6) is similar to the one of ZEP520A (etch rates, mr-PosEBR: 190nm/min, ZEP520A: 150nm/min, silicon: 440nm/min). Moreover, high resolution nanopatterns in mr-PosEBR could be smoothly transferred into the underlying Si substrate by a RIE process.

Graphene engineering by neon ion beams

Achieving the ultimate limits of lithographic resolution and material performance necessitates engineering of matter with atomic, molecular, and mesoscale fidelity. With the advent of scanning helium ion microscopy, maskless He+ and Ne+ beam lithography of 2D materials, such as graphene-based nanoelectronics, is coming to the forefront as a tool for fabrication and surface manipulation. However, the effects of using a Ne focused-ion-beam on the fidelity of structures created out of 2D materials have yet to be explored. Here, we will discuss the use of energetic Ne ions in engineering graphene nanostructures and explore their mechanical, electromechanical and chemical properties using scanning probe microscopy (SPM). By using SPM-based techniques such as band excitation (BE) force modulation microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy, we are able to ascertain changes in the mechanical, electrical and optical properties of Ne+ beam milled graphene nanostructures and surrounding regions. Additionally, we are able to link localized defects around the milled graphene to ion milling parameters such as dwell time and number of beam passes in order to characterize the induced changes in mechanical and electromechanical properties of the graphene surface.

The composition and photolithographic process of high- thermostability ultraviolet positive photoresist

Photoresist is a crucial and fundamental material for photolithographic technology, which plays a vital role in microelectronic technique. The rapid development of lithography drives the microelectronic technique moving forward. With high-level and multifunctional photoresist, it can make finer patterns and meet the demand under harsh working environment such as high temperature. To evaluate the performance of the photoresist, one of the most important indicators is line/space resolution, while the composition of the photoresist and photolithographic process have a very significant influence on the resolution performance. Different composition may result in different photosensitivity and solubility of the photoresist, which have a significant impact on the performance. Moreover, the photolithographic processes include exposure dose (exposure time), developing time, the concentration of developer and so on. They all have severely affected the lithography pattern quality and lithography performance. Thus, the related research in detail is very necessary and it is conducive to maximize the performance of the photoresist and guide lithography process to be carried out smoothly as well. In this work, a high thermal-stability ultraviolet (UV) positive photoresist was obtained from the formulation of a self-made amide-imide copolymer as matrix resin, a 2,1,5-diazonaphthoquinone sulfonyl chloride derivative as photosensitizer, and solvent. The optimal composition and photolithographic process parameters was studied by simple variable method. It was found that the optimal composition was with the 1:4:10 (mass ratio) proportion of photosensitizer, resin and solvent, and the optimal photolithographic process parameters were about 4500 r/min spin-coating, prebake 1 min at 110°C hot plate, 30 s exposure time, 25 s development time in 1.0% tetramethylamine hydroxide (TMAH) aqueous solution, and post bake 5 min at 120°C hot plate. The imaging contrast of this photoresist was about 3.35, which indicated that the positive part and negative part of the pattern had obvious boundary. In the condition of contact exposure the lithography process above, the optimal line/space resolution was about 1 μm. In addition, the photoresist had high thermal-stability. After hard baking 30 min at 270°C, the photoresist had no obvious collapse of the photolithography pattern. This is because the self-made amide-imide copolymer has high thermal-stability and it acts as matrix resin in the photoresist. With the high thermal-stability property, the photoresist can meet the requirements of some used under high temperature environment and lays a foundation for the lithography technology being applied and developed under complex circumstance.