Deviation Of Film Thickness Research Articles

A hard mask process and alignment device aims to achieve high consistency and mass-scale production of gas sensors based on spraying hydrothermal gas sensing material.

The material synthesized through the hydrothermal method has received extensive and in-depth study in recent years, with a large number of literature reporting their excellent performance in the fields of catalysis or gas sensitivity. In order to combine the hydrothermal material with micro-electro-mechanical system processes to achieve large-scale manufacturing of hydrothermal synthesized materials at the wafer-level, this paper proposes a series of processes for hard mask patterned electro-atomization spraying of hydrothermal materials and designs and manufactures an alignment device that achieves the alignment of silicon hard mask and electrode wafers based on the vacuum clamping principle. Through experiments, it has been verified that this device can achieve micrometer-level alignment between the hard mask and the electrode wafer. By conducting electro-atomization spraying, hard mask patterning, optical microscopy, and confocal laser scanning microscope measurements, as well as gas sensitivity testing on a CeO2/TiO2 hydrothermal composite material published in our previous research, it was further verified that this process has good film formation consistency (Sa and Sq are both less than 3μm and the average film thickness deviation is less than 5μm), excellent and consistent gas sensitivity performance, and good long-term working stability. This article provides a promising process method for the large-scale production of hydrothermal synthesis materials at the wafer-level.

LONG-WAVE MODELS FOR A COUNTERCURRENT FLOW OF LIQUID FILM AND TURBULENT GAS FLOW

The paper considers the countercurrent flow of a vertically falling liquid film and a turbulent gas. In the case of small Reynolds numbers and when certain conditions for the characteristics of such a flow are met, the problem is reduced to one model equation for the film thickness. For long-wave weakly nonlinear disturbances, various nonlinear integrodifferential equations are obtained from this equation for the deviation of film thickness from the undisturbed level. Their specific type depends on the values of the magnitude of one parameter. This parameter is the ratio of the friction force from the side of the gas acting on the unperturbed film flow to the force of gravity. It is shown that, in addition to the countercurrent flow, such models also appear in a number of other gas-film flows. Both their radical differences and some common features are discussed. Several universal solutions of these model equations are presented.

Improving Liquid Film Thickness Uniformity of Semiconductor Etching Equipment Using Flow Field Visualization and CFD Simulation

With the rapid development of semiconductor-based products, semiconductor and integrated circuit (IC) design industries have become indicators of global technological advance in this field. As IC structure becomes smaller and smaller, improved process technology and equipment are necessary to maintain and improve wafer yield rates and quality. Among them, the etching technology in the process has a close relationship with the size of IC structure. According to extensive research and analyses put forward by predecessors, the etching process and methods that affect the yield rates and quality of wafers have been well characterized. This study investigates the spray etching method of the single nozzle and double nozzle. Using computational fluid dynamics software developed by Ansys Fluent, the fluid is injected from the center as the starting point at the same flow rate and speed, and according to 2, 4, and 8 seconds of a different cycle and nozzle forms, moving back and forth to supply liquid on the surface of the 300 mm disc. It is assumed that fluid properties do not change with temperature. Additionally, the chemical reaction and thermal reaction of the etching process are not considered. Changes in the surface flow field resulting from different nozzles and cycle conditions are observed. This study involved setting up a set of flow field visualization systems, replacing the etching liquid with colored water, using a digital camera to capture the relationship between the gray index and the thickness of the water film, and calculate the film thickness. The average film thickness deviation ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t}_{avg}$ </tex-math></inline-formula> ) and variable quantity ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${dt}$ </tex-math></inline-formula> ) were characterized and used as a means to compare performance. The results show that the average film thickness deviation of the double nozzles is higher than the single nozzle, and variable quantity ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${dt}$ </tex-math></inline-formula> ) is lower than that of the single nozzles. In general, the double nozzles increase the thickness and stability of the liquid film thickness on the surface of the disc.

Remanufacturing of the waste refractory Mo–10Nb sputtering target by spark plasma sintering technology

Mo–10Nb refractory sputtering targets used in the flat panel display industry have attracted extensive attention, whereas the shortcoming of low target utilization is now urgently needed to be solved. This work is to repair the waste Mo–10Nb target by spark plasma sintering (SPS) at 1550 °C and 10 min, and the feasibility is demonstrated. It is shown that the repaired target retains identical phases and high purity. Clean and strong bonds are found at the repair interface. Regardless of the position, the repaired target exhibits finer grains as well as higher density, microhardness, and thermal conductivity compared with the original target. The two targets are then sputtered to obtain relevant films. Both films consist of the same phases and show columnar appearances. Mo, Nb, O, and C are present in both films, where Mo and Nb exist in the form of pure Mo, MoO2, MoO3, pure Nb, and Nb2O5. A higher sputtering rate, smaller film thickness deviation, grain size and surface roughness, less oxidation, and larger elastic modulus and nano-hardness are obtained from the film prepared by the repaired target. SPS is proven to be a well-suited method for producing the regenerated target.

Filtering characteristics of 1D photonic crystal with Gaussian film thickness perturbation.

Conventional theoretical and numerical studies on photonic crystal, which often does not consider the film thickness error during the experimental preparation process, will meet a large deviation between the experiment and the simulation. The filtering characteristics of one-dimensional (1D) photonic crystals with random film thickness errors (modeled as the Gaussian distribution) are systematically investigated by statistical method and numerical simulations. By studying the influence of the deviation of film thickness and the period number on the filter characteristics, it shows that the forbidden bandwidth is reduced to 80.27% of the intrinsic energy band when the film thickness deviation is σ=0.25a. Furthermore, we found that introduction of a slight disturbance of the film thickness (σ=0.01a) to photonic crystal will broaden the forbidden bandwidth to 100.49%. The proposed photonic crystal model with film thickness deviation can reduce the error between experiment and theory, which can be used for designing broadband photonic bandgaps. These structures have potential applications such as light-matter interactions, ultra-small filters, and photonic chips.

Modeling wave modes for a countercurrent flow of film and turbulent gas

In this paper, wave modes are modeled for a countercurrent flow of vertically falling liquid film and turbulent gas. In the case of small Reynolds numbers for long wave perturbations, the problem is reduced to a nonlinear integro-differential equation for the film thickness deviation from the undisturbed level. Solutions of this model equation are studied. Several typical scenarios for the evolution of periodic perturbations are presented

Simulating waves on a horizontal liquid film entrained by a gas flow

Nonlinear waves on a horizontal liquid film surface are considered. The effect of adjacent gas flow is taken into account through the data on shear stress at the film-gas interface obtained by the Boussinesq model of turbulence. A model nonlinear equation for the film thickness deviation from the undisturbed level is used to simulate nonlinear wave modes. Weakly nonlinear steady-state travelling solutions of this equation with wave numbers located in the vicinity of neutral wave numbers are constructed analytically. The evolution of periodic perturbations with wave numbers lying in the depth of the linear instability region is also considered numerically. Several typical scenarios of their evolution have been identified.

Studying the topological structure of steady-state travelling solutions for the model of film flow of a viscous fluid entrained by a gas flow

The article studies nonlinear waves on a liquid film, flowing under the action of gravity in a known stress field at the interface. In the case of small flow rates for the long-wave modes, the problem is reduced to solving a nonlinear equation for the film thickness deviation from the undisturbed level. The paper presents the results of calculations for this model equation of families of steady-state travelling periodic solutions. For these families, the limiting solutions, solitary waves, have been found. It is also investigated how the topological reorganization of such families occurs with a smooth change in the degree of influence of the gas flow. It is shown that although the eigenform of specific solitons changes smoothly, for certain values of the problem parameter for a particular family an abrupt change in the shape of its limiting soliton occurs.

A small-mode model for spatial regimes on a freely falling liquid film

Spatial wave modes of a viscous liquid film freely flowing down a vertical wall are considered. In the case of small Reynolds numbers the problem is reduced to considering solutions of a nonlinear equation for the film thickness deviation from the undisturbed level. It was used to obtain a model system of equations, describing spatially periodic solutions with wave numbers lying in the vicinity of special resonance points and symmetric in the transverse coordinate. Several solutions for this system are provided.

Study of multi-objective optimization of process parameters in film posting based on outside mold decoration

In order to optimize the process parameters in film posting based on outside mold decoration (OMD), the polymethyl methacrylate (PMMA) plastic sheets were tested in uniaxial tensile tests at high temperature with different temperatures and strain rates. The coefficients of the viscoelastic constitutive model called Duan Saigal Greif Zimmerman (DSGZ) were calculated based on the uniaxial tensile tests, and the predicted curve of DSGZ model and experimental data were compared and analyzed. The user material subroutine in ABAQUS of the DSGZ model was designed and written by adopting elastic prediction-radial consumers algorithm and was integrated into ABAQUS for the simulation of forming process of mouse shell posting film using the OMD process. After solving the model, the film thickness distribution and its deforming distribution in the X- and Y-direction were obtained. The optimization objective was to minimize the standard deviation of film thickness and its deforming distribution in the X- and Y-direction for 50 nodes on the thin film of mouse shell. The process parameters of OMD were sampled based on the method of optimal Latin hypercube design. In addition, the radial basis functions model was built. As the analysis shows, the radial basis functions model is sufficiently accurate. Based on the models, the process parameters of OMD were multi-objective optimized and analyzed by adopting archive-based micro-genetic algorithm. The best process parameters group was obtained after comprehensive analysis.

Modeling nonlinear wave regimes in a falling liquid film entrained by a gas flow

The article studies nonlinear waves on a liquid film, flowing under the action of gravity in a known stress field at the interface. In the case of small Reynolds numbers, the problem is reduced to solving a nonlinear integro-differential equation for the film thickness deviation from the undisturbed level. The nature of branching of wave modes of the unperturbed flow with a flat interface has been investigated. The steady-state traveling solutions with wave numbers that are far enough from the neutral ones, have been numerically found. Using methods of stability theory, the analysis of branching of new families of steady-state traveling solutions has been performed. In particular, it is shown that, similarly to the case of the falling film, this model equation has solutions in the form of solitons-humps.

Simulating nonlinear steady-state traveling waves on the falling liquid film entrained by a gas flow

The article is devoted to the simulation of nonlinear waves on a liquid film flowing under gravity in the known stress field at the interface. The paper studies nonlinear waves on a liquid film, flowing under the action of gravity in a known stress field at the interface. In the case of small Reynolds numbers the problem is reduced to the consideration of solutions of the nonlinear integral-differential equation for film thickness deviation from the undisturbed level. The periodic and soliton steady-state traveling solutions of this equation have been numerically found. The analysis of branching of new families of steady-state traveling solutions has been performed. In particular, it is shown that this model equation has solutions in the form of solitons-humps.

Simulating nonlinear steady-state traveling waves on the falling liquid film entrained by a gas flow

The article is devoted to the simulation of nonlinear waves on a liquid film flowing under gravity in the known stress field at the interface. In the case of small Reynolds numbers the problem is reduced to the consideration of solutions of the nonlinear integral-differential equation for film thickness deviation from the undisturbed level. Weakly nonlinear steady-state traveling solutions of the equation with wave numbers in a vicinity of neutral wave numbers are constructed analytically. The nature of the wave branching from the undisturbed solution is investigated. Steady-state traveling solutions, whose wave numbers within the instability area are far from neutral wave numbers, are found numerically.

Simulating nonlinear waves on the surface of thin liquid film entrained by turbulent gas flow

A new system of equations has been derived to simulate the dynamics of long-wave perturbations on the surface of a thin layer of viscous liquid, flowing down a vertical plane and blown by co-current turbulent gas flow. The analysis of linear stability of the unperturbed flow has been performed. It has been found that at moderate Reynolds numbers of liquid, Benjamin linear model and model of boundary conditions transfer to the unperturbed level for a disturbed gas flow give qualitatively similar results. With decreasing Reynolds number differences between the results obtained by different turbulence models become more pronounced. In the case of small Reynolds numbers of fluid, the system of equations results in a single evolution equation for film thickness deviation from the undisturbed level. Some solutions of this equation have been considered.

Numerical shaper optimization for sputtered optical precision f ilters

A novel optimization procedure for optical precision sputter coaters with respect to the film homogeneity is demonstrated. For a coater concept based on dual cylindrical sputtering sources and a rotating turn-table as sample-holder, the inherent radial decay of the film thickness must be compensated by shaper elements. For that purpose, a simulation model of the particle flux within such a coater is set up and validated against experimental data. Subsequently, the shaper design is optimized according to the modeled metal flux profile. The resulting film thickness deviations are minimized down to ±0.35%.

Regulation of film thickness, surface roughness and porosity in thin film growth using deposition rate

This work focuses on distributed control of film thickness, surface roughness and porosity in a porous thin film deposition process using the deposition rate as the manipulated input. The deposition process includes adsorption and migration processes and it is modeled via kinetic Monte Carlo simulation on a triangular lattice with vacancies and overhangs allowed to develop inside the film. A distributed parameter (partial differential equation) dynamic model is derived to describe the evolution of the surface height profile of the thin film accounting for the effect of deposition rate. The dynamics of film porosity, evaluated as film site occupancy ratio, are described by an ordinary differential equation. The developed dynamic models are then used as the basis for the design of a model predictive control algorithm that includes penalty on the deviation of film thickness, surface roughness and film porosity from their respective set-point values. Simulation results demonstrate the applicability and effectiveness of the proposed modeling and control approach in the context of the deposition process under consideration.

Production of MF and DC-pulse sputtered anti-reflective/anti-static optical interference coatings using a large area in-line coater

This paper is on the deposition of antistatic and antireflective coatings (ARAS coatings) based on TiO 2, SiO 2 and ITO films on 300 × 300 mm 2 glass substrates using a production-like in-line sputter system with a cathode length of 750 mm. In order to achieve a reproducible and homogenous deposition process, we studied the deposition of single and multilayer systems for different process conditions. The optical constants and individual layer thicknesses have been determined by variable angle spectroscopic ellipsometry and spectroscopic photometry as well as by X-ray reflectometry (XRR). With this information we used sequent redesigns of the ARAS stack in order to compensate for film thickness deviations during the deposition of the multilayer stack. Approaches to minimize the drawbacks of depositing optical coatings using in-line sputter systems are shown.

P-170: Advanced Photo Spacer Technology for Large-sized TFT-LCD

During ODF(one drop filling) process technology, the height, volume and elastic recovery ratio of photo spacer(PS) are very critical factors for liquid crystal injection process window and cell gap in the assembly of TTFT-LCD panel module. Experimental results showed that photo spacer height is very sensitive to any pre-layer photo resist residue and film thickness deviation. In the ODF process, liquid crystal injection window is related to photo spacer height, volume and elastic recovery ratio.

Nanotopography impact in shallow-trench isolation chemical mechanical polishing—analysis method and consumable dependence

The nanotopography of the surface of silicon wafers has become an important issue in ULSI device manufacturing, as it affects the post–chemical mechanical polishing (post-CMP) uniformity of the thickness deviation of dielectric films. A spectral method is proposed to examine quantitatively how the nanotopography impacts the film thickness deviation during CMP. The nanotopography impact was investigated in terms of its dependence on the characteristics of consumables, such as the polishing pad hardness and the wafer manufacturing method. In addition, the effects of the surfactant and the abrasive size in ceria slurry on nanotopography impact were investigated. It was found that the magnitude of the post-CMP oxide thickness deviation due to nanotopography increased with the surfactant concentration in the case of smaller abrasives but was almost independent of the concentration in the case of larger abrasives. These results demonstrate that the nanotopography impact can be controlled by manipulating the slurry characteristics.

Power, efficiency, and polarization analysis of a beamsplitter for the equipartition of infrared input power in the presence of angular, film-thickness, and spectral deviations

A high-efficiency beamsplitter for the equipartition of infrared input power using combined reflection and transmission is described. The new design does not use a back metal reflector coating, and hence is more efficient than those previously described. The beamsplitter uses a parallel slab of fused silica that is strip coated with a germanium film on the front and back sides to generate four beams of equal powers. A specific design for operation at the 1.55-µm fiber communication wavelength is presented. Power, efficiency, and polarization analysis of fractional beams in the presence of angular, film-thickness, and spectral deviations near the equipartition condition are discussed. The following results are obtained. An angular deviation of ±0.5 deg has no significant effect on power (<0.1%), efficiency (<0.02%), or polarization (ellipsometric) parameters (< 1 deg) of the fractional beams. A film-thickness deviation of ±10 nm results in a small change in power (<2%), efficiency (<0.1%), and polarization (<0.5 deg) of the fractional beams. A spectral variation of ±25 nm also has a small effect on power (<1.5%), efficiency (<0.01%), and polarization (<1 deg).