Glass Carrier Research Articles

Laser lift-off of polyimide thin-film from glass carrier using DPSS laser pulses of top-hat square profiles

Laser lift-off (LLO) process using a diode pumped solid state (DPSS) laser with wavelength of 355 nm and pulse width of 37 ns was investigated experimentally and theoretically for non-contact delamination of the polyimide (PI) substrate from the glass carrier. Each pulse emitted from the DPSS laser was shaped into a top-hat square beam by an optical system including a diffractive optical element lens and a spatial filter. The typical FWHM size of the top-hat beam was 315μm×328μm. The train of pulses was irradiated on the specimen in the form of a quasi-line beam through a scanner system for two representative pulse repetition rates (PRR) of 1 and 150 kHz. Experimental observations and theoretical simulations using the photothermal ablation model clarified that the intensive laser pulse induced extremely fast ablation inside the PI substrate, which caused the PI to delaminate internally along the PI/glass interface, leaving a residual PI layer of about 100 nm in thickness on the glass carrier. The successful non-overlap LLO by each pulse was confirmed optically by the Fizeau fringes at the threshold fluence of 240 mJ/cm2. The overlapping irradiation of laser pulses, which minimized overlay or stitch errors, was able to lower the threshold fluence of each pulse by about 50% compared to the non-overlapping irradiation by a single pulse. With increasing PRR for the same number of irradiation overlaps, the threshold fluence was reduced considerably due to the thermal accumulation effect, but the thickness of the residual PI layer remaining on the glass carrier increased slightly.

An Investigation of Photocatalytic Activity of Coatings Based on Strontium Bismuthate Deposited on a Ceramic Carrier

A study was carried out to obtain effective photocatalytic coatings on a ceramic silicate carrier. The analysis of the characteristics of silicate materials, such as: ceramic carrier "Biopur"; porous glass carrier "Siporax"; glass-ceramic carrier (sitall) "Biopur forte" produced by the company "SERA", Germany, was made. According to X-ray phase analysis data, it was shown that the “Biopur” ceramic support is formed by magnesium aluminosilicates of the composition MgAl2Si3O10 and MgAl2Si4O12. The porous material “Siporax” is X-ray amorphous. The silicate material “Biopur forte” does not have a pronounced amorphous component in its structure and can be assigned to the class of sitall with a high SiO2 content and a low content of alkali and alkaline earth metal cations in the structure. A method for impregnating a ceramic support with a solution of a bismuth photo-catalyst precursor, a specially developed composition of a complex of bismuth with sorbitol, is considered. An effective concentration of a solution of a complex of bismuth with sorbitol in ethanol equal to 10% was found. By low-temperature pyrolysis at , photo-catalytically active coatings of strontium bismuthates were obtained on each of the considered types of ceramic supports. The highest photocatalytic activity was detected in the coating deposited on a ceramic carrier with a glass structure – “Biopur forte”. A study of the photocatalytic activity of coatings, based on strontium bismuthate, depending on the multiplicity of coating on a “Biopur forte” ceramic carrier, was made. The effective number of layers of the photocatalytic coating on a “Biopur forte” ceramic carrier is determined, which corresponds to the highest rate of decrease in the optical density of a model organic pollutant upon irradiation with visible light in the spectrum.

Study on treatment of printing and dyeing waste gas in the atmosphere with Ce-Mn/GF catalyst

Glass fiber (GF) was selected as catalyst carrier, and the experiment was carried out to modify the glass fiber without catalyst carrier, so that it could achieve the best loading effect. The activity of the waste gas from the catalytic combustion of polyester cotton with Ce-Mn/GF series of catalysts decreased in the following order: Ce-Mn/GF (1:5), Ce-Mn/GF (1:4), Ce-Mn/GF (1:6), Ce-Mn/GF (1:3), and Ce-Mn/GF (1:2) (Ce/Mn ratio is molar ratio). When O2 concentration was less than 6%, O2 had a great influence on the reaction and is the main control factor of the reaction. However, when O2 concentration was higher than 6%, the influence of O2 concentration could be basically ignored, and the gas condition of the reaction became the main influence factor of the reaction. The activity of the catalyst was related to its specific surface area and pore structure. The specific surface area of the catalyst was affected by the loading capacity of metal oxide CeO2 and MnOx. The catalysts of Ce-Mn/GF (x) series (x ≠ 0), Mn existed in the state of Mn4+. The active centers CeO2 and MnOx are amorphous and uniformly dispersed on the carrier glass fiber.

A chemiluminescence-based heterogeneous asymmetric recombinase polymerase amplification assay for the molecular detection of mycotoxin producers.

The analysis of mold in indoor air is a prominent topic but it is hardly dealt with. The most affected fields of this issue are residential- and occupational safety since mold can have a number of impacts on human health. To date the most used methods for quantification of microorganism contamination in indoor air are culture- or microscopy-based and are not capable of translating the on-site situation to analytical data reliably. Here we present a chemiluminescence-based method to detect mycotoxin producers through isothermal amplification of mycotoxin biosynthesis genes using glass and polycarbonate carriers. In this proof-of-principle study, zearalenone producers were aimed to be detected by heterogeneous asymmetric recombinase polymerase amplification (haRPA). For this, an appropriate lysis method for fungal spores was developed allowing rapid access to DNA. A system calibration with spores of Fusarium culmorum as zearalenone-producing organism resulted in an LOD of 2.7 × 105 spores per ml. The system was shown to be specific for zearalenone producers. This work presents the first application of a heterogeneous isothermal amplification for rapid detection and quantification of mycotoxin producers. In the future, a multiplex detection can be possible by haRPA.

Laser Debonding of Ultrathin Wafers and Packages: A Technology for the New Generation of Electronic Devices

The continuous shrinkage of the device wafers thickness is driving the current mature debonding technologies to their limits. The challenging form factor demands for memory (≤ 30 µm) or new generations of power devices applications are just two examples for the need of lowering the device thickness.Slide-off as well as mechanical debonding are methods currently in use in high volume production, but these two technologies are not capable to support the new requirements in terms of thermal and mechanical stability, handling, throughput (affecting the cost of ownership - CoO), and process margin. Therefore, device manufactures are looking for a more versatile, universal debonding technology. State of the art UV laser debonding is a very promising candidate which can help bringing the required process margin and flexibility. By combining laser debonding and thermoset materials with a high thermal budget the process window can be significantly enhanced.Most of the thermoset materials of interest which are used to form a bond and to embed the device topography cannot be stimulated directly with UV light. In order to enable a debonding process for these materials, an additional layer is commonly deposited on the carrier. The post bond uniformity (quantified typically by the total thickness variation - TTV) of the used bulk layer of thermoset adhesive has to be very well controlled in order to enable a defect free thinning of the device wafer: this becomes crucial particularly when the final device layer has to be thinned down below 10 µm. Besides the optimization of the bond layer thickness uniformity, suitable carriers for different devices and applications were evaluated. Due to the significant variety of the available glass carriers, a customized temporary bonding process can be developed by selecting the most appropriate adhesive and carrier combinations suitable even for very challenging substrates, like reconstituted wafers.Reconstituted wafers consist of a number of different layers and materials with different thermal expansion coefficients, which makes the stress management and the handling of such substrates extremely difficult. However, the choice of the suitable carrier enables the processing independent of the chosen integration process flow (RDL first; Chip first). Even a carrier flip flop to enable the processing of the back side of the very thin package is possible and this is enabling the creation of ultra-thin and smart packages.The scope of the current work was to address the post bond adhesive thickness uniformity as well as the stress management. Experimental results will be presented for the process optimization: figure 1 shows two bow measurement results for two different carrier materials and figure 2 shows an example of post-bonding thermoset adhesive uniformity measurement Figure 1

A novel photolithographic method for fabrication of flexible micro-patterned glucose sensors

Abstract We developed a new photolithographic method for introducing micro-patterned metal array onto flexible substrates without the substrates being affected by temperature, solvent, or UV exposure. We used SL-03, acrylate copolymer as a separation layer between glass carrier and metal pattern, and transferred the micropattern from the glass to a flexible substrate in the last step of the process. Through the developed micropatterning technology, we successfully fabricated the glucose sensor. The proposed glucose sensor has a LOD of 1.2 μM and a dynamic range from 0.05 to 0.30 mM, which covers the screening of diabetes in sweat. The sensor showed a good stability and reproducibility in mechanical deformation and continuous glucose monitoring conditions. In addition, miniaturized multiple glucose sensors were fabricated in limited area, which provided the exceptional accuracy (R2 ≈ 0.9978) compared to the mono glucose sensor. These results confirm that the proposed glucose sensors based on new photolithographic method are highly promising for application as healthcare sensors such as continuous glucose level monitoring on a flexible devices.

Threshold voltage shift-proof circular oxide thin film transistor with top and bottom gates for high bending stability

Negligible threshold-voltage shift is reported for oxide thin-film transistors (TFTs) under high current (3 μA) and tensile bending stress (2 mm radius). The good stability is attributed to a circular TFT structure with electrically shorted top and bottom gates, and a polyimide substrate embedded with carbon-nanotubes for mechanical support and damage-free detachment from carrier glass. The circular structure leads to uniform electric field distribution across the channel, hard saturation in output characteristics, independence from tensile bending direction-related degradation, as well as isolation of the channel from stress concentrated points, which arise from local electric-field crowding at sharp corners or channel edges. The double-gate topology increases gate-drivability and achieves volume-accumulation, which minimizes the influence of defects at the channel surface and slight variations in carrier concentration during stress. Furthermore, the presence of two gates slightly shifts the location of the neutral bending plane towards the oxide semiconductor, thereby significantly reducing strain.

High Heat Resistant Peelable Temporary Bonding Film and New Debonding System with Xe Flash Light Irradiation

Abstract We have developed a new temporary bonding film (TBF) and new debonding system with Xe flash light irradiation, named photonic release system, for advanced package assembly process. Since new TBF has a high Tg over 200 °C after curing and shows good chemical resistance to developer, resist stripper, and plating chemicals, no delamination, voiding, and swelling were observed after thermal and chemical treatment in the bonded structure of wafer and glass carrier. In addition, by adopting a metal-sputtered glass carrier, wafer could be debonded by Xe flash light irradiation in less than 1 ms through the glass carrier with no damage. Residual TBF on the wafer surface could be peeled off smoothly at ambient temperature without residue on the wafer. In this research, we also demonstrated the good applicability of this temporary bonding film to the typical packaging process by using test vehicle including 12 inch mold wafer and the advantage of photonic release system.

8‐4: Invited Paper: Flexible glass Substrate for OLED Lightning Application ans Efficient Internal Light Extraction for OLED Lightning Devices

We discuss application of Corning® Willow® Glass for OLED Lighting integrated substrate which includes an internal light extraction layer for high efficacy. Two technologies – (1) glass carrier, and (2) edge healing, needed for successful product development will be discussed.

Hydrophilic direct bonding and debonding of ultrathin glass substrates for high-temperature devices

The direct hydrophilic bonding and debonding of ultrathin glass substrates onto and off from a glass carrier has been investigated, and a methodology is presented to reduce the excessive bonding strength after high-temperature annealing to facilitate the debonding process. It is found that with a preliminary surface conditioning of glasses at 300 °C and 400 °C in vacuum at 1 mbar before bonding, the specific surface energy of bonded wafers after high-temperature annealing for 30 min reduces to about 72% and 50% as compared to the control samples that have been surface-conditioned at room temperature instead.

Immobilization of unspecific peroxygenase expressed in Pichia pastoris by metal affinity binding

Unspecific peroxygenases (UPOs) catalyze oxidation and oxygenation reactions using only hydrogen peroxide as a co-substrate. Especially their ability to oxygenate unactivated C–H bonds has attracted interest in their synthetic application. Due to the high production cost of these heme-enzymes, special care has to be taken to fully utilize the catalyst. Immobilization is one strategy to achieve this as it allows recovery and reuse of the costly biocatalyst. Herein, we investigate the immobilization of an UPO-variant (AaeUPO-PaDa-I) originally from Agrocybe aegerita by fusion of a C-terminal hexa-histidine tag and subsequent metal affinity binding on porous glass carriers (EnginZyme EziG). The fusion protein was expressed in Pichia pastoris, purified and characterized. The specific activity did not change considerably with slightly reduced activities ranging from 78% to 53% of the untagged enzyme. Using this immobilization procedure, it was possible to retain the full catalytic potential of the enzyme in terms of product produced, which is shown for a benzylic hydroxylation process. The reusability of the immobilized catalyst was demonstrated by carrying out repeated fed-batch operation for multiple cycles. As a proof of concept, we demonstrate the immobilization directly from crude culture broth, which has the potential to greatly simplify immobilization as no purification steps are necessary.

Flexible IGZO thin-film transistors and inverter circuits with diode-connected transistors fabricated on transparent polyimide substrates

Amorphous In2O3–Ga2O3–ZnO (a-IGZO) thin-film-transistors (TFTs) have attracted increasing attention in recent years due to their potential on flexible electronics applications. We investigated low-temperature-processed a-IGZO TFTs and inverters on transparent polyimide. We had successfully implemented flexible top-gate staggered a-IGZO TFTs and inverter circuits on transparent polyimide-based nanocomposite substrates using fully lithographic, etching and PECVD processes that are compatible with existing TFT mass fabrication technologies. The TFTs showed decent performances (with mobility > 20 cm2/V s) as de-bonded from the carrier glass. Furthermore, the IGZO-based inverter also showed decent performances (voltage gain > 1.5) and is considered as a potential pathway toward flexible electronics.

Storage stability of freeze-dried arazá (Eugenia stipitata Mc Vaugh) powders. Implications of carrier type and glass transition

Arazá, a flavorsome fruit rich in antioxidants (phenolics/carotenoids/flavonoids/ascorbic acid) may be appropriate for preparing powdered-functional foods and beverages. Variations in water-activity (aw) and matrix physical state (glassy/rubbery) can induce undesirable changes in dehydrated products color antioxidant composition/activity reducing shelf-life. Solving this problem requires a thorough analysis of the aw/physical state effects on the arazá powder physicochemical properties. Objectives were to: (a) analyse aw, glass-transition temperature (Tg) and carrier-type (maltodextrin-DE10/Arabic-gum) effects on freeze-dried arazá color, antioxidant composition/activity; (b) Determine storage-time influence on antioxidant content/activity/polyphenol composition considering the best performing aw values previously determined. Critical aw values calculated from Tg/aw interrelationship overestimated the aw limit corresponding to samples color/antioxidant composition/activity maximum stability, therefore, Tg was not a reliable indicator of the properties stabilities. Antioxidant content/activity storage behavior (20 °C/aw = 0.11 (best performing aw optimized across all properties)) were satisfactorily predicted by the Weibull equation. Shelf-lives, calculated considering 90% properties retention as the acceptability limit, were 34 (arazá/maltodextrin) and 50 (arazá/Arabic-gum) days. Polyphenolic profile included 6 phenolic acids, one coumaric acid derivative, 4 flavonoids and one ellagitannin. Using a mix of maltodextrin-DE10/Arabic-gum might improve antioxidant content/activity stability obtained with the single carriers and extend their shelf-life.

Ablation of polyimide thin-film on carrier glass using 355 nm and 37 ns laser pulses

Ablation of the polyimide (PI) thin-film deposited on glass substrate was investigated theoretically and experimentally to find out the important characteristics during the laser-lift off (LLO) process for the fabrication of flexible electronics. Instead of using conventional ablation induced by the front irradiation on the specimen, the LLO process employs the backside irradiation on the specimen transferred through the glass substrate, assuming that the ablation occurs volumetrically in the narrow region inside the PI film near the PI and glass interface. Experimentally the PI film on glass was exposed to a pulse laser beam emitted from UV laser of 355 nm in wavelength and 37 ns in duration. Depths and morphologies of the ablation spots were observed by the surface profiler and the FE-SEM. Theoretically the ablation process was estimated by the photothermal mechanism, using the one-dimensional heat conduction equation with volumetric absorption of the laser beam. It was shown that the experimental ablation could be described through the theoretical analysis based on the surface and the bulk photothermal models. While the former assumed that the ablation occurred only on the ablation front surface, the latter assumed the ablation was accompanied by the thermal and volumetric bond breakage. In general, the theoretical calculations agreed well with the experimental observations. In particular, the experimental observations of the ablation for the backside irradiation case that was the core phenomenon in the LLO process was explained appropriately by the features predicted using the bulk model.

Study Photo Imagable dielectric (PID) and non-PID on process, fabrication and reliability by using panel glass substrate for next generation interconnection

Abstract In 1965, Gordon E. Moore, the co-founder of Intel stated that numbers of transistors on a chip will double every 18 months and his theory called the Moore's Law. The law had been the guiding principle of chip design over 50 years. The technology dimension is scaling very aggressively in IC foundry. For example, TSMC announced their 5nm Fin Field-Effect Transistor (FinFET) process technology is optimized for both mobile and high performance computing applications. It is scheduled to start risk production in the second half of 2019.[1] To overview the semiconductor supply chain included IC foundry, wafer bumping, IC carrier, PCB (Printed circuit board) and OSAT (oversea assembly and testing)… etc., the IC carrier and PCB technology dimension scaling are far behind than the IC foundry since many reasons for the traditional industry. The industry needs different kinds of breakthrough approaches for the scaling of via and strip line in next generation interconnection. Traditional organic substrates faces many challenges of warpage, surface roughness and material dimension stability issues for manufacturing and high density I/Os with very fine line interconnections. To breakthrough these challenges, the materials of glass carrier, new photo-imagable dielectric (PID) and advanced equipment were evaluated for the fine line and fine via interconnection. In the papers, there are many PID and non-PID materials were surveyed and compared for fine via (< 10μm) interconnection or low loss of high frequency application. The first candidate was chosen for redistribution layers (RDL) fabrication by using 370mm × 470mm glass panels. Semi additive process (SAP) was used for direct metallization on glass panel with different build-up dielectric materials to form daisy chain test vehicles. The process, fabrication integration and electrical measurement results of daisy chain showed good continuity and electric resistance in the glass panel substrate. The reliability of the thermal cycling test (TCT) and highly accelerated stress test (HAST) were evaluated as well in this study.

Panel Warpage of Fan-Out Panel-Level Packaging Using RDL-First Technology

In this study, fan-out panel-level packaging (FO-PLP) technology using a redistribution layer (RDL) first approach is demonstrated using a large glass panel as a carrier (550 mm × 650 mm size). Finite-element analysis (FEA) is conducted to investigate process-dependent panel-level warpage with considering material selection of photo-dielectric, glass carrier and molding compound, structure design, and process optimization. Taguchi method is implemented to identify important parameters resulting in large panel warpage in each process and further parametric studies are also conducted with detailed FEA simulation. The effect of gravity on panel warpage has been simulated and analyzed in this study by considering the panel process and panel size. Modeling gravity effect reduces the panel warpage significantly, which is very close to the real case and is validated by warpage measurement results. Therefore, the gravity effect on warpage needs to be modeled for the large panelwarpage simulation to achieve accurate simulation results.

Ultrathin flexible thin film transistors with CYTOP encapsulation by debonding process

We fabricated ultrathin flexible thin film transistors with hydrophobic encapsulation layer by debonding process. In the debonding process, to separate the transistors from the carrier glass in deionized (DI) water, a strong hydrophobic material such as CYTOP was used for encapsulation, thus increasing their resistance to moisture. PVA was used as a release layer and the debonding process was optimized to separate the carrier glass and the transistors. It was confirmed that water penetration into the device can be suppressed effectively when the CYTOP thickness is 800 nm. In addition, the electrical characteristics remained almost constant even in the presence of water for 50 min. The total thickness after debonding process was approximately 2 μm. Waterproof experiments and debonding process were performed for a simple inverter circuit as well as a discrete device, and the operation and voltage gain of the inverter did not change when water was placed on the device or after debonding process. Finally, the flexibility was measured by transferring the device to a flexible PI substrate. Consequently, it was confirmed that degradation in the electrical properties was slightly up to a bending radius of 2.5 mm.

Characterization on the operation stability of mechanically flexible memory thin-film transistors using engineered ZnO charge-trap layers

The charge-trap memory thin-film transistors (CTM-TFTs) using ZnO charge-trap layer (CTL) were fabricated and characterized, in which ZnO CTL was deposited by atomic layer deposition (ALD) and the deposition temperatures were controlled to be 75, 100, and 125 °C to improve both specifications of device characteristics and stability for the flexible memory devices. The CTM-TFT using ZnO CTL deposited at 100 °C obtained a wide memory window (MW) of 14.7 V, large memory margin between ON- and OFF-states (ION/IOFF, 7.3 × 106) at 1 µs voltage pulses. The ION/IOFF larger than 107 was also obtained with a progress of retention time. It was noteworthy that the deposition temperature for the ZnO CTL was worked as one of the most important control parameters affecting the memory device characteristics of the fabricated flexible CTM-TFTs. Alternatively, the fast program operation and long retention time were suggested to result from a suitable number of trap sites and their appropriate positions within the ZnO CTL prepared at 100 °C. The improved device stabilities were guaranteed even under bending condition at a radius of curvature of 10 mm after the delamination process of PI film substrate from carrier glass.

48‐1: Impact of Carrier Glass Substrate Characteristics on Flexible OLED Display Production

The impact of the characteristics of carrier glass substrate on flexible OLED display production was studied. Non‐negligible thermal shrinkage was observed even though heating temperature is relatively low. In addition, deformation of the substrate was found to be caused by dividing into two or more sheets.

Charge-trap-assisted flexible nonvolatile memory applications using oxide-semiconductor thin-film transistors

We introduce mechanically flexible nonvolatile memory thin-film transistors (MTFTs) for future highly functional flexible and stretchable electronic devices and systems. The proposed memory devices are uniquely composed of oxide-semiconductor thin films and operated with charge-trap and detrap mechanisms for nonvolatile memory operations. Charge-trap-assisted MTFTs (CT-MTFTs) using In–Ga–Zn–O active and ZnO charge-trap layers are designed and fabricated on flexible poly(ethylene naphthalate) and colorless polyimide films prepared on carrier glass substrates. We describe the fabrication processes and evaluation methodologies for realizing flexible CT-MTFTs in a detailed way and discuss related technical issues. The device characteristics and memory performance of the fabricated flexible CT-MTFTs, including when the devices are mechanically strained, are extensively discussed. We also propose further improvements for remaining issues on device performance from the viewpoints of memory operations and mechanical flexibility.