Large Glass Substrates Research Articles

Micr -Transfer Printing for Efficient 3DHI of 100-300mm Wafers and Glass Panels

This paper presents an analysis of using micro-transfer printing (MTP) for three-dimensional heterogeneous integration (3DHI) of diverse components made using 100mm, 200mm and 300mm wafers with large area glass substrates. Techniques for achieving high throughput and high wafer and substrate utilization, despite their size mis-matches, are described in detail along with MTP’s pros and cons versus alternative wafer-to-wafer and die-to-wafer 3DHI technologies. MTP, a massively parallel pick-and-place process, efficiently transfers large arrays of ultra-thin (<10 micron), small, diverse components (“x-chips”) from one or more source wafers to destination substrates. MTP enables disruptive 3DHI of compound semiconductors, including GaN, GaAs, InP, SiGe and emerging materials, silicon and passive components for wireless and optical communications, power management, sensor, photonics and other analog / mixed signal applications. Since the x-chips are ultra-thin and active side up, standard copper redistribution layer (RDL) technology may be readily used to interconnect the x-chips and destination die, resulting in very short path lengths and, hence, minimum parasitics. ASM AMICRA and X Display Company supply R&D and production MTP manufacturing systems. More than twenty MTP systems are installed worldwide at X-FAB, Micross Components, Tyndall National Institute, Teledyne, the Naval Research Laboratory, the University of Illinois Urbana Champaign, the University of Ghent / imec, UPVfab and undisclosed leading manufacturers.

Large-Scale Terahertz Sensor Array Module With Antenna-Coupled Microbolometers on Glass Substrate With Sigma–Delta ADC Readout ASIC

We describe the design, fabrication and demonstration of a terahertz sensor array module, designed to operate over 250-350GHz. The antenna coupled microbolometer was fabricated on a glass substrate with an integrated array of pixel switches and row multiplexing circuitry implemented with LTPS (Low Temperature PolySilicon) thin film transistors. While other microbolometer arrays have been reported for the upper Terahertz bands, we focus on lower frequencies where adequate semiconductor sources are available potentially enabling important medical and security applications. The devices were fabricated in a Gen 3.5 flat panel manufacturing facility implementing what we call Large Area MEMS Platform (LAMP) surface micromachining process, providing a path to low-cost manufacturing. Individual pixels were defined on a 0.7mm pitch across an array of 128x128 pixels in this first demonstration. Since flat panel fabrication capabilities use large, single-shot reticle masks and large glass substrates, physically larger arrays can be manufactured without mask stitching. An ROIC (readout integrated circuit) was demonstrated to support the THz sensor panel with 648 input channels, each providing an independent sigma delta ADC with excellent uniformity and 12 effective number of bits. An early demonstration of the sensor array is described, imaging a metallic knife hidden in a cardboard envelope.

High-Speed Handling Robot with Bionic End-Effector for Large Glass Substrate in Clean Environment.

The development of “large display, high performance and low cost” in the FPD industry demands glass substrates to be “larger and thinner”. Therefore, the requirements of handling robots are developing in the direction of large scale, high speed, and high precision. This paper presents a novel construction of a glass substrate handling robot, which has a 2.5 m/s travelling speed. It innovatively adopts bionic end-suction technology to grasp the glass substrate more firmly. The structure design is divided into the following three parts: a travel track, a robot body, and an end-effector. The manipulator can be smoothly and rapidly extended by adjusting the transmission ratio of the reducer to 1:2:1, using only one motor to drive two sections of the arm. This robot can transfer two pieces of glass substrate at one time, and improves the working efficiency. The kinematic and dynamic models of the robot are built based on the DH coordinate. Through the positioning accuracy experiment and vibration experiment of the end-effector, it is found that the robot has high precision during handling. The robots developed in this study can be used in large-scale glass substrate handling.

34.4: High electrical stability nanocrystalline silicon BCE TFTs for outdoor display application on large glass substrates

We have fabricated high stability nanocrystalline silicon (NanoSi) on large glass substrate and investigated the effects of silane content ratio (SC), power, space and pressure on NanoSi thin‐film growth, deposition rate and its electrical characteristics on bottom‐gate back‐channel etch TFTs using 4 mask process. The single film results show that the key factors affecting the deposition rate are power and silane content and a suitable thickness is benifit for high mobility TFT manufacture. Multiple sets of data show that the main impact factor for electrical charecteristics of NanoSi TFTs is SC and pressure. Through the analysis of bias stress data, we can find that the electrical stability of NanoSi TFTs is better than that of a‐Si:H TFTs with lower Vth shift about 2.22 V of PBTIS and ‐1.29 V of NBTIS. It is because the defect state of NanoSi is produced by charge trapping and is negligible.

A theoretical design method for the nozzle pitch of air-flotation system to reduce large liquid crystal display glass substrate\u2019s deformation

The deformation of large glass substrate in air-flotation system affects detection accuracy of inspection instrument. According to the gas lubrication theory, Timoshenko’s thin film theory and the simulation figure of the pressure distribution of the air film flow field, the air load distribution model of the air film is established, and the deformation expression of the large liquid crystal glass substrate in air-flotation system is given. On this basis, a theoretical design method for designing nozzle pitch of orifice throttling air-flotation system was proposed. Combined with examples, the results of theories and simulation are compared. An experiment on the deformation of the glass substrate was carried out on an experimental prototype. The difference between the experimental results and the theoretical results does not exceed 10%.

Optical inspection path planning for large liquid crystal glass substrate detection instrument.

A large liquid crystal glass substrate detection instrument usually uses the air flotation platform to support a glass substrate. The glass substrate will be deformed by air pressure on the air flotation platform, which will affect the accuracy of detection. In this paper, combined with the characteristics of the detection method of the detection instrument, an optimal detection scanning path with the minimum deflection variation range of the glass substrate is planned so as to minimize the influence of glass substrate deformation on the detection accuracy. In theory, the calculation model of the deflection variation ranges of different paths on the glass substrate is established, the numerical method is used to solve it, and finally, the optimal scanning path for the optical inspection is obtained. The experimental results verify the correctness of the model.

P‐46: Fabrication and characterization of thick Cu films deposited on G8.5 LCD glass substrates for 8k and large TV panels

The deposition of thick Cu films on large glass substrates, for instance G8.5 and G10.5 is challenging but essential for large size and 8k TV sets. The inevitable temperature rising during metal deposition results in a series of severe issues such as film oxidation and glass bending, which have been seldom investigated. In the paper, the process issues leading by thick Cu film deposition have been disclosed and solutions have been discussed. Film properties as surface roughness, grain size and electrical resistivity have been characterized and the results will help improve the performance of thick Cu wires.

Precise thickness profile measurement insensitive to spatial and temporal temperature gradients on a large glass substrate.

When manufacturing glass substrates for display devices, especially for large-sized ones, the time-varying spatial temperature gradient or distribution on the samples is remarkably observed. It causes serious degradation of thickness measurement accuracy due to the combination of thermally expanded thickness and temperature-dependent refractive index. To prevent or minimize the degradation in thickness measurement accuracy, the temperature distribution over an entire glass substrate has to be known in real time in synchronization with the thickness measurement to specify the refractive index of the sample based on an exact mathematical model of the temperature-dependent refractive index. In this paper, a measurement method for determining the thickness profile of a large glass substrate regardless of precise measurement of temperature distribution and the mathematical model of the refractive index was demonstrated. The widely used glass substrates with nominal thicknesses of 0.6 mm and 1.3 mm were measured at room and high temperatures. Through comparison of thickness profiles of hot glass substrates having large temperature gradients and those estimated through thermal expansion of thickness profiles measured at room temperature, it was confirmed that the proposed method can provide highly reliable thickness measurement results under such challenging conditions, unlike simple calculation from the optical thickness using the well-known refractive index.

Nanostructured and oriented metal-organic framework films enabling extreme surface wetting properties.

We report on the synthesis of highly oriented and nanostructured metal–organic framework (MOF) films featuring extreme surface wetting properties. The Ni- and Co- derivatives of the metal–catecholate series (M-CAT-1) were synthesized as highly crystalline bulk materials and thin films. Oriented pillar-like nanostructured M-CAT-1 films exhibiting pronounced needle-like morphology on gold substrates were established by incorporating a crystallization promoter into the film synthesis. These nanostructured M-CAT-1 MOF films feature extreme wetting phenomena, specifically superhydrophilic and underwater superoleophobic properties with water and underwater oil-contact angles of 0° and up to 174°, respectively. The self-cleaning capability of the nanostructured, needle-like M-CAT-1 films was illustrated by measuring time-dependent oil droplet rolling-off a tilted surface. The deposition of the nanostructured Ni-CAT-1 film on a large glass substrate allowed for the realization of an efficient, transparent, antifog coating, enabling a clear view even at extreme temperature gaps up to ≈120 °C. This work illustrates the strong link between MOF film morphology and surface properties based on these framework materials.

Solution assisted roll-coating of transparent conducting oxide thin films for organic photovoltaic applications

Transparent conduction oxide (TCO) thin films are one of the key material in optoelectronic applications. These materials are usually produced by vacuum-based methods such as magnetron sputtering, both for laboratory work and for commercial purposes. Alternative methods for producing large-scale TCO films are needed. In this work, a non-vacuum coating technique for preparation of TCO thin films on large area glass substrates was presented. Tin doped indium oxide (ITO) thin films were successively coated on glass substrates by non-vacuum based roll coating method. A low electrical resistivity of ~1.3 × 10−3 Ωcm and high optical transmittance of 84% in the visible region were obtained for ITO thin film samples. Furthermore, an ITO/PEDOT PSS/P3HT:PCBM/LiF/Al structured organic photovoltaic cell was also prepared on non-vacuum roll coated ITO thin films. The device with the roll coated ITO thin film exhibits a power conversion efficiency of 1.83%, average short-circuit current density (Jsc) of 7.4 mA/cm2, open-circuit voltage (Voc) of 0.590 V, and fill factor (FF) of 0.42.

Atmospheric-pressure plasma by remote dielectric barrier discharges for surface cleaning of large area glass substrates

A remote dielectric barrier discharge (RDBD) plasma system has been used to clean glass-surfaces under atmospheric pressure. To achieve a sustainable process, it is critical to optimize the parameters that affect the surface condition. Hence, the physical and chemical properties of the glass surface were investigated by changing the input voltage and the distance between the sample and electrodes. The optical emission spectroscopy (OES) characteristics were analyzed as a function of the gas concentration, and contact angles were measured before and after plasma treatments. The contact angle was reduced from 50 degrees (hydrophobic) to 5 degrees (hydrophilic) after the RDBD plasma treatment on the bare glass. The temperature of the samples was under 55 °C during the process without electrostatic charge. In this paper, we demonstrated the superior cleaning effectiveness of removing inorganic and organic contaminants on the glass surface using the RDBD without surface damage.

High-Quality Schottky Barrier Diodes on β-Gallium Oxide Thin Films on Glass Substrate

Structural, electrical and optical properties of monoclinic gallium oxide thin films, deposited by pulsed laser deposition on glass substrates, are reported. The influence of growth temperature on thin film properties was investigated. Further, Ga2O3 buffer layers, grown and/or annealed at different temperatures, can be used to reduce the surface roughness of subsequently grown thin films. On thin films obtained from optimized growth parameters, Schottky barrier diodes were fabricated by reactive magnetron sputtering of Pt. Interestingly, Schottky diodes realized on thin films on glass substrate (without optimized buffer layer) have similarly good properties as diodes realized on thin films grown epitaxially on c-plane sapphire. The results stimulate realization of e. g. solar-blind photo detectors on low cost and possibly large area glass substrates.

SILAR grown Ag nanoparticles as an efficient large area SERS substrate

AbstractAg nanoparticles having different size and coverage are grown on large area glass substrate (~10 cm2) using low cost successive ionic layer adsorption and reduction (SILAR) method. The SILAR parameters, such as reduction time and growth cycles are optimized to grow Ag nanoparticles with appropriate size and coverage showing maximum surface enhanced Raman scattering (SERS) enhancement of Rhodamine 6 G(R6G). For fixed growth cycles, the size and the coverage of the grown Ag nanoparticles are found to increase with the reduction time and then saturate. The size and coverage of the grown Ag nanoparticles monotonically increase with growth cycles. However, for higher growth cycles, the shape of Ag nanoparticles could not maintain their sphericity and became rock shaped/nonspherical particles, giving rise to intense quadruple plasmon resonance. The growth mechanism is proposed. Further, SERS activity of the grown Ag nanoparticles is studied for an industrial pollutant methylene blue (MB). The observed SERS enhancement factor (~109) for MB is much higher than the reported values in literature. Measured relative standard deviations values of Ag nanoparticles grown with optimum SILAR parameters suggest the excellent homogeneity and reproducibility of the SERS signal.

Transparent conducting Al:ZnO thin films on large area by efficient cylindrical rotating DC magnetron sputtering

Al: ZnO (AZO) thin film provides non-toxic, cost effective visible light transparent conductive front contact for various photonic and electronic applications. Development of AZO thin films on large area soda lime glass substrates using direct current magnetron sputter coater with cylindrical rotating ceramic targets is investigated and is presented in this work. Design of experiments and Investigation on detailed structural, electrical, optical characterization was carried out to fine tuning of various sputter process parameters such as sputtering power, pressure and substrate temperature to obtain uniform electrical conductivity and transmittance over a large area. The best resistivity of 4.07 × 10−4 Ω cm and transmittance of 84% with thickness uniformity better than 97% on 300 mm × 300 mm area glass substrate was achieved on the AZO thin films sputtered using optimized process conditions.

Direct copper metallization on TGV (Thru-Glass-Via) for high performance glass substrate

Abstract IoT (Internet of things) society will be coming in the near future, and everything will be connected by the Internet. Consequently, data traffic will be increased, and so will the demand to improve the performance of communication devices. Currently, plastics and ceramics are commonly used as insulating materials for communication components, but they are getting close to the limit in terms of material properties, because the next generation high performance communication devices require signal frequency of 20GHz and beyond. Therefore, further improvements in the properties of the insulating materials as well as in the performance of electronic devices are being demanded. Copper conformal metallization on glass provides many opportunities for high frequency electronic devices. The most obvious advantage is given by the material properties. The glass substrate was chosen for low conductivity and low dielectric loss for high frequency application, and for its scalability to the larger area panels with low cost. While applications require strong interfacial adhesion between copper film and glass substrate, glass is often inferior as compared to metal-to metal adhesion. Direct copper metallization on glass is conventionally a difficult task, and it usually does not provide enough peeling strength either. Therefore, forming Ni and Ti seed layers by sputtering and precursors deposited by sol-gel method are being studied. However, these processes have been limitedly used or not been used in mass production, because creation of vias and simultaneous formation of seed layers on both sides by sputtering is difficult to undertake. The Sol-gel method does not provide stable peel strength and it takes a long process. This additional process requirement to add a layer to promote the adhesion of Cu to glass burdens the factories in a couple of ways: 1) enlarging the glass substrate is difficult due to the limitation in equipment size, 2) forming the film inside the through holes is also difficult due to high-aspect ratio via requirements, and 3) high cost due to slow processing speed. In an earlier reports, we presented evidence that we have successfully demonstrated direct copper plating on glass, showing the adhesion strength of 0.42kN/m between glass and copper seed layer. In the present work, we are reporting wet plating process which enables easy and uniform film formation on large glass substrates and inside through holes. This low cost wet plating process enables forming copper film directly on glass without adhesion layer and enhancing the adhesion strength without degrading glass properties and copper conductivity.

Direct growth of 2D and 3D graphene nano-structures over large glass substrates by tuning a sacrificial Cu-template layer

We demonstrate direct growth of two-dimensional (2D) and three-dimensional (3D) graphene structures on glass substrates. By starting from catalytic copper nanoparticles of different densities and using chemical vapour deposition (CVD) techniques, different 2D and 3D morphologies can be obtained, including graphene sponge-like, nano-ball and conformal graphene structures. More important, we show that the initial copper template can be completely removed via sublimation during CVD and, if need be, subsequent metal etching. This allows optical transmissions close to the bare substrate, which, combined with electrical conductivity make the proposed technique very attractive for creating graphene with high surface to volume ratio for a wide variety of applications, including antiglare display screens, solar cells, light-emitting diodes, gas and biological plasmonic sensors.

Scalable parallel self-assembly of nanoparticle anti-reflection coatings

Here we report a simple, inherently parallel, and scalable bottom-up approach for fabricating nanoparticle anti-reflection coatings on large glass substrates. Negatively charged silica nanoparticles are electrostatically adsorbed onto a surface-functionalized glass substrate with positive surface charges to form a disordered monolayer nanoparticle coating. Systematic experiments have been conducted to optimize the critical process parameters, including the dispersing dielectric media, nanoparticle concentration of the colloidal suspensions, and the coating time, that significantly affect the uniformity and the anti-reflection properties of the final coatings. Specular reflection and transmission measurements demonstrate that good anti-reflection performance (with <1% two-sided reflection) and high optical transmission (>99%) can be achieved by the self-assembled nanoparticle coatings. This innovative technology also enables the simultaneous coating of multiple 5-in.-sized glass substrates with high and reproducible qualities. Importantly, we combine experiments with theoretical calculations to address a fundamental question faced by the fabrication of monolayer nanoparticle-based anti-reflection coatings — what is the optimal nanoparticle surface area coverage for best anti-reflection performance? Our optical simulations based on a rigorous coupled-wave analysis model indicate that the optimal nanoparticle coverage is ~60% which is readily achievable by this electrostatics-assisted bottom-up technology.

54-1: Parallel Fabrication for Integration of Electronic and Microelectromechanical Systems

We have developed a four mask top gate a-Si:H based process that allows for the parallel production of TFTs, Schottky diodes and surface MEMS elements on large area glass substrates. Simple electronical and micromechanical devices as well as a complex active matrix driven MEMS display demonstrator have been produced for process verification. Furthermore, the process seems to be feasible for applications like ultrasonic transducers or energy harvesting.

Novel GIMS technique for deposition of colored Ti/TiO₂ coatings on industrial scale

AbstractThe aim of the present paper has been to verify the effectiveness and usefulness of a novel deposition process named GIMS (Gas Injection Magnetron Sputtering) used for the flrst time for deposition of Ti/TiO₂ coatings on large area glass Substrates covered in the condition of industrial scale production. The Ti/TiO₂ coatings were deposited in an industrial System utilizing a set of linear magnetrons with the length of 2400 mm each for covering the 2000 × 3000 mm glasses. Taking into account the speciflc course of the GIMS (multipoint gas injection along the magnetron length) and the scale of the industrial facility, the optical coating uniformity was the most important goal to check. The experiments on Ti/TiO₂ coatings deposited by the use of GIMS were conducted on Substrates in the form of glass plates located at the key points along the magnetrons and intentionally non-heated during any stage of the process. Measurements of the coatings properties showed that the thickness and optical uniformity of the 150 nm thick coatings deposited by GIMS in the industrial facility (the thickness differences on the large plates with 2000 mm width did not exceed 20 nm) is fully acceptable form the point of view of expected applications e.g. for architectural glazing.

Vibration-insensitive measurements of the thickness profile of large glass panels.

We propose and realize a modified spectral-domain interferometer to measure the physical thickness profile and group refractive index distribution of a large glass substrate simultaneously. The optical layout was modified based on a Mach-Zehnder type interferometer, which was specially adopted to be insensitive to mechanical vibration. According to the measurement results of repeated experiments at a length of 820 mm along the horizontal axis, the standard deviations of the physical thickness and group refractive index were calculated to be 0.173 μm and 3.4 × 10(-4), respectively. To verify the insensitivity to vibration, the physical thickness values were monitored at a stationary point while the glass panel was swung at an amplitude exceeding 20 mm. The uncertainty components were evaluated, and the combined measurement uncertainty became 161 nm (k = 1) for a glass panel with a nominal thickness of 0.7 mm.