Temperature Storage Test Research Articles

Development of starch-based films with enhanced hydrophobicity and antimicrobial activity by incorporating alkyl ketene dimers and chitosan for fruit preservation

Using hydrophobic antimicrobial food packaging films offers significant opportunities to extend the shelf life of food. This study developed a hydrophobically modified starch-based film incorporating alkyl ketene dimers (AKDs) and chitosan (CS) for mango preservation. The film's physicochemical properties and structural characteristics were comprehensively analyzed. The successful integration of AKDs into the starch (ST) matrix was confirmed through FT-IR, XRD, XPS, and SEM techniques, which revealed the establishment of β-ketoester linkages via esterification. The addition of AKDs significantly enhanced the film's hydrophobicity and mechanical properties, attributed to chemical cross-linking and the formation of intermolecular hydrogen bonds. In an eight-day room temperature storage test, the ST-AKD/CS films effectively extended the shelf life of mangoes by four days compared to the control and ST groups. As all components of the film are environmentally friendly and biodegradable, these hydrophobic films offer a promising solution for prolonging the freshness of mangoes while maintaining sustainability.

Can Layered Oxide/Hard Carbon Sodium-Ion Pouch Cells with Simple Electrolyte Additives Achieve Better Cycle Life than LFP/Graphite Cells?

This study explores the impact of simple electrolyte additives on the performance of layered oxide/hard carbon sodium-ion pouch cells. The cycle life of these cells between 2.0 and 3.8 V is assessed at various temperatures (20, 40, and 55 °C) with different solvent systems based on ethylene carbonate, diethyl carbonate, and dimethyl carbonate. A particular challenge in these cells is gas generation at high temperature. Pouch bag experiments which separate the charged electrodes to measure their gas generation from reactions with the electrolyte show that hard carbon generates no gas, but the sodium layered oxide produces large amounts of gas. Isothermal microcalorimetry corroborates these results with parasitic heat flow measurements of pouch bags and full pouch cells. A crosstalk mechanism is revealed which lowers gas generation and reduces parasitic heat flows in full cells. The electrolyte additives prop-1-ene-1,3-sultone, sodium difluorophosphate, and 1,3,2-dioxathiolane-2,2-dioxide (DTD) are effective at reducing gas generation and heat flow from the positive electrode. They also reduce self-discharge in elevated temperature storage tests. Overall, 1 M NaFSI in EC:DMC (15:85) with 2% DTD is the best electrolyte for the sodium-ion pouch cells in this work. Eventually, the performance of these cells is compared to optimized LiFePO4/graphite cells.

Reliability of the hybrid bonding level using submicrometric bonding pads

Hybrid bonding is a major enabler for devices requiring 3D stacking with high interconnection density. An in-depth reliability study is performed for the specific Cu/SiO2 integration to identify the potential failure mechanisms. A high robustness is evidenced down to bonding pitch 0.81 μm for the standard reliability tests such as Thermal Cycling (TC) tests, High Temperature Storage (HTS) test, Stress induced Voiding (SiV), Time Dependent Dielectric Breakdown (TDDB) or electromigration. The hybrid bonding interface is stable under thermal stress with no atomic or ionic Cu diffusion observed through the hybrid bonding interface. The role of the thin self-formed cuprous oxide at the Cu/SiO2 interface in the case of misaligned bonding pads is believed to play a major role in the high robustness to reliability tests.

Study on the Solder Joint Reliability of New Diamond Chip Resistors for Power Devices

New diamond chip resistors have been used in high-power devices widely due to excellent heat dissipation and high-frequency performance. However, systematic research about their solder joint reliability is rare. In this paper, a related study was conducted by combining methods between numerical analysis and laboratory reliability tests. In detail, the shape simulation and thermal cycling finite element simulation for solder joints with different volumes were carried out. The optimized solder volume was 0.05 mm3, and the maximum thermal cycling stress under the optimized shape was 38.9 MPa. In addition, the thermal cycling tests with current and high temperature storage tests were carried out for the optimized solder joint, which showed good agreement with the simulation results, clarified the growth and evolution law of intermetallic compound at the interconnection interface, and proved the optimized solder joint had great anti-electromigration, temperature cycling and high temperature storage reliability. In this work, an optimized solder joint structure of a diamond chip resistor with high reliability was finally obtained, as well as providing considerable reliability data for the new type of diamond chip resistors, which would boost the development of power devices.

Solderability and Reliability of Sintered Nano-Ag Bond Pads of Printed Re-Distribution Layer

Abstract Redistribution layer (RDL) is one key enabling technology for advanced packaging. RDL is usually fabricated at wafer level by a photolithography process. An alternative approach for implementing RDL by additive manufacturing (AM) method is proposed in this study. This allows RDL to be fabricated on a singulated chip. Nanosilver (nano-Ag) ink is printed on the silicon chip to form routing traces and bond pads. However, the Ag pad may be consumed by the solder quickly if the reflow process is not properly controlled. The mechanical integrity of the solder joint was evaluated by both solder ball shear and die shear tests. A high temperature storage test and humidity test were carried out to evaluate the solder joint reliability. Experiment results showed that the Ag pad fabricated by AM is compatible with surface mount technology (SMT). Reliable solder joints on the Ag pad were achieved. There was no significant change in the Ag3Sn intermetallic compound (IMC) layer thickness and mechanical strength after aging at high temperature and high humidity conditions. There was no early solder joint failure observed. The finding of the present study will serve as a very useful reference for the future practice of forming solder joints on sintered nano-Ag pads.

An Investigation into Thermomigration Failure of Flip Chip Solder Joint Interconnects used in High Reliability Applications

Abstract The experimental study described herein investigates thermomigration of both eutectic Sn/Pb and lead free Sn/Ag/Cu solder joints, with the additional focus on the development of an Arrhenius failure model of time-to- failure as a function of temperature. Flip chip test vehicles were assembled with daisy chain die, with and without underfill, attached to ceramic and organic package substrates, using standard reflow processes. Three different under bump metallurgy technologies were investigated: sputtered thin film Al/NiV/Cu, thick electroplated nickel, and thick electroplated copper (i.e., copper pillars). The test vehicles were subjected to unbiased high temperature storage (HTS) testing with temperatures ranging from 125°C to 200°C. Failure was determined from continuity testing at regular intervals until an open circuit or high resistivity was detected. The results demonstrate the robustness of Al/NiV/Cu UBM at temperatures less than 130°C, and of the thick electroplated UBM at temperatures of 150°C. Based on the HTS test results, and corresponding analyses, a thermomigration failure model was generated for eutectic Sn/Pb and lead free Sn/Ag/Cu solder alloys using an Arrhenius-like fit to the failure data.

Terminal Sinter-Bonding Using Silver Paste for Aluminum Nitride Heater

In this study, a Ag sintered joint was applied to replace the high-Pb solder to bonding materials between Aluminum Nitride (AlN) substrates and terminals used in wafer bake processes. The Ag sintered joint was fabricated using an optimized temperature profile. The high-Pb solder specimens were fabricated using a conventional reflow process. An X-ray analysis and mechanical properties evaluation of the specimens were performed. Subsequently, a high temperature storage test was performed for a high temperature reliability evaluation. The initial void analysis result showed that the Ag sintered joint and high-Pb solder joint had approximately 1%, and 20% voids, respectively. After being stored at a high temperature of 280 ℃ for 1000 h, the shear strength of the high-Pb solder joint decreased by approximately 27% owing to the Pb degradation. However, the shear strength of the Ag sintered joint was maintained. After 1000 h of a high temperature storage test, growth of Ni3Sn4 intermetallic compound and Kirkendall voids were observed at the high-Pb solder interface. Furthermore, a Ag-Au layer was observed at the sintered Ag interface. In addition, the sintered Ag joints densificated after the high temperature storage test.

Electrical and Microstructural Reliability of Pressureless Silver-Sintered Joints on Silicon Carbide Power Modules Under Thermal Cycling and High-Temperature Storage

Low-temperature and pressureless silver (Ag) sintering was applied to a 1200 V/200 A silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) power module with a Ag-finished silicon nitride active metal-brazed substrate, and the results were evaluated for applicability in electric and hybrid electric vehicles. The sintering was performed at 220–240°C, 90 min in vacuum under nitrogen gas conditions; the bonding strength, bonding layer thickness (BLT), void content, and densification of the as-sintered Ag joints were 39 MPa, 71.4 µm, 2%, and 90.5%, respectively. The shear strength, BLT, densification, and microstructure of the Ag-sintered joints were compared before and after the thermal cycling test (− 50–150°C, 1100 cycles, TCT) and high temperature storage test (200°C, 1000 h, HTST). To simultaneously compare the electrical properties of the SiC power module with lead (Pb)-free solder joints, the same SiC MOSFET power module was manufactured using a Sn-3.0Ag-0.5Cu (SAC305) Pb-free solder. The shear strength and densification after TCT and HTST were 35.5 MPa and 39.7 MPa, as well as 92.8% and 94.8%, respectively. The on-resistance and total switching efficiency of the SiC power module with the Ag-sintered joint were also compared to those of the SAC305 solder joint module, which evinced maximum values of 7.3 mΩ and 10.7 mJ that were superior to those of 8.5 mΩ and 11.3 mJ for the SAC305 solder joint, respectively. Under the same measurement conditions, the maximum generated current and voltage values are lower than those of the solder joint module, so it is envisaged that stable power module operation is realizable for long-term use. The Ag-sintered joint surpassed the SAC305 solder interconnects in terms of the electrical and mechanical reliability of the power module. When a SiC wide band gap device was used, it was discovered that Ag sintering was superior to Pb-free solder interconnects to increase the power conversion efficiency of the power module.

The Effect of Leveler in Cu Electroplating Solution on the Bump Reliability of Flip Chip Packaging

From the previous studies [1,2], it was well known that the voids at the interface of copper (Cu) and tin-silver (Sn-Ag) severely affects the bump reliability of flip chip packaging. And it was also suggested that impurity atoms existing in electroplated Cu film accelerate those voids formation [3]. So, in this study, we investigated the impact of leveler of Cu electroplating solution on the non-metallic impurities of electroplated Cu film and the voids at the interface of Cu and Sn-Ag solder was studied. We have found that the non-metallic impurity concentration was dominantly influenced by the adsorption characteristics of leveler. Fig. 1(a) shows the non-metallic impurity concentration in the electroplated Cu films using the electroplating solution containing different leveler. We can lower the total non-metallic impurity concentration to 14.9 ppm by changing the leveler. And we confirmed that 90% of voids at the interface of Cu and Sn-Ag solder can be reduced even after high temperature storage test at 150°C for 1000 hours, as shown in Fig. 1(b). Reference [1] C.Y. Liu, K.N. Tu, T.T. Sheng, C.H. Tung, D.R. Frear, P. Elenius, J. Appl. Phys. 87, 750 (2000)[2] P.S. Teo, Y.-W. Huang, C.H. Tung, M.R. Marks, T.B. Lim, 50th Electronic Components and Technology Conference, Las Vegas, NV, USA, p. 33 (2000)[3] T. Laurila, V. Vuorinen, J.K.Kivilahti, Mater. Sci. Eng. R, 49, 1 (2005) Figure 1

Analysis of Cylindricity Error of High and Low Temperature Storage Tested Alternator Stators

This paper investigates the internal shape correctness of alternator stators occurring in high and low temperature storage tests. This kind of failure can affect the adequate operation of alternators since vibrations can occur during rotation of the other part of the alternator, the rotor. This error can reduce the efficiency of the alternator. The aim of this study is to examine the influence of different testing parameters, such as the temperature and the running time of the test, and whether or not the stator is equipped with a damping element. For the experiments we used the full factorial experimental design method. The measurement of the cylindricity of the specimens was done with a circular and position error measuring machine. From the measured data, special improvement ratios can be calculated in order to define the appropriate range of testing parameters that resulting greater deformity. A further aim is to compare the different cylindricity parameters and the features of theirs measured values.

Surface‐Modified Ni‐Rich Layered Oxide Cathode Via Thermal Treatment of Poly(Vinylidene Fluoride) for Lithium‐Ion Batteries

Combination of poly(vinylidene fluoride) (PVDF) with Ni‐rich layered cathode material create artificial cathode‐electrolyte interphases by thermal decomposition of PVDF and residual Li+ species. The pressure of the cell cycled with PVDF‐treated cathode materials is markedly decreased, since the thermal treatment with PVDF selectively reduces the amounts of Li+ species. The cycling performance is improved compared to nontreated Ni‐rich layered cathodes because the artificial cathode–electrolyte interphases effectively suppress the electrolyte decomposition as determined by systematic characterization of particle hardness, surface morphology, and electrochemical impedance spectroscopy. Additional high temperature storage tests performed with 3450‐dimensioned pouch cells indicate much improved recovery rates, as well as smaller open circuit voltage drops, smaller increases in internal resistance, and less swelling for cells cycled with the PVDF‐treated Ni‐rich layered cathode than with a nontreated Ni‐rich layered cathode.

Experimental and Theoretical Studies of Cu-Sn Intermetallic Phase Growth During High-Temperature Storage of Eutectic SnAg Interconnects

In this paper, the growth of intermetallic compound (IMC) layers is considered. After soldering, an IMC layer appears and establishes a mechanical contact between eutectic tin-silver solder bumps and Cu interconnects in microelectronic components. Intermetallics are relatively brittle in comparison with copper and tin. In addition, IMC formation is typically based on multi-component diffusion, which may include vacancy migration leading to Kirkendall voiding. Consequently, the rate of IMC growth has a strong implication on solder joint reliability. Experiments show that the intermetallic layers grow considerably when the structure is exposed to heat. Mechanical stresses may also affect intermetallic growth behavior. These stresses arise not only from external loadings but also from thermal mismatch of the materials constituting the joint, and from the mismatch produced by the change in shape and volume due to the chemical reactions of IMC formation. This explains why in this paper special attention is being paid to the influence of stresses on the kinetics of the IMC growth. We develop an approach that couples mechanics with the chemical reactions leading to the formation of IMC, based on the thermodynamically sound concept of the chemical affinity tensor, which was recently used in general statements and solutions of mechanochemistry problems. We start with a report of experimental findings regarding the IMC growth at the interface between copper pads and tin based solder alloys in different microchips during a high temperature storage test. Then we analyze the growth kinetics by means of a continuum model. By combining experiment, theory, and a comparison of experimental data and theoretical predictions we finally find the values of the diffusion coefficient and an estimate for the chemical reaction constant. A comparison with literature data is also performed.

Investigation of Various Bumps and Redistribution Lines to Inhibit Protected Silicon Nitride Cracks in High Pattern Density Chip Package

Mechanical stress related to chip packaging failure is the most common reliability issue in semiconductor devices, especially for high pattern density of very-large-scale integration. In this paper, redistribution lines (RDL) corresponding to gold and copper materials with capped layers (Sn-Ag and Au-Ni) were evaluated to investigate the structure dependency on the mechanical properties of intermetallic compounds, and to provide a solution to improve chip package reliability in regard to protect Si3N4 cracks. The simulation results revealed that a thicker Si3N4 film combined with the corner rounding of bump/RDL structures could mitigate Si3N4 film cracks. Voids induced by the fine pitch configuration of the top Al increase the potential risk of Si3N4 cracks during chip packaging. The reflow temperature is a major factor increasing the thermal stress in RDL patterns rather than from the bump structure. A high temperature storage test applied to the Cu pillar/Sn-Ag capping was used to investigate the intermetallic compound growth, shear strength, and hardness.

Interfacial evolution and mechanical properties of Au–Sn solder jointed Cu heat sink during high temperature storage test

The growth of interfacial intermetallic compounds (IMC) and mechanical properties by the widely used Au-Sn solder jointed Cu pillar are studied in this paper. Three concentrations of Sn (15%, 20%, and 25%) are employed to investigate the evolution of IMC growth and mechanical properties. It is found that the initial IMC growth is linear growth and surface reaction domination at the reflow step, as both Au and Sn directly react with Cu to form scallop-like (Au,Cu)Sn. Following the initial growth, IMC gradually becomes thicker, which inhibits Au/Sn penetrating into IMC to react with Cu, thus, at this stage, AuCu instead of (Au,Cu)Sn, forms the IMC and the inter-diffusion of parabolic growth dominates. By increasing HTS time, AuCu3 grows by consuming the AuCu compound. Moreover, the AuSn eutectic precipitations gradually decreased, which resulted in reduced hardness. Ductile fractures appeared among all the samples, and the appropriate IMC thickness improved the adhesion ability of the Au-Sn solder on the Cu pillar.

Systematic evaluation of cyanate ester/ epoxidized cresol novolac copolymer resin system for high temperature power electronic packaging applications

The power electronics industry has been actively seeking high temperature stable epoxy molding compound (EMC) materials that can meet the requirements for encapsulating future SiC chips operating at a temperature (250 °C) that exceeds the capability of current epoxy chemistry. This work provides a detailed evaluation of a high heat resistant cyanate ester (CE)/epoxidized cresol novolac (ECN) copolymer system with varied compositions regarding their high temperature performances. Owing to the novolac nature of ECN which provides a high crosslink density, it is found that the copolymers with a low CE concentration (25–33 mol%) are able to produce a comparable glass transition temperature (>230 °C) and decomposition temperature (T10%>400 °C) to those of the high CE formulations. Moreover, long-term high temperature (250 °C) storage test of reveals a less severe weight loss and blistering in the lower CE formulations. A distinguished degradation mechanism involving hydrolysis of unreacted cyanate groups in the high CE compositions was determined through various thermal and chemical analyses. It was concluded that the CE/ECN copolymers with low CE concentrations are promising candidates for the high temperature EMC formulation.

A felületvasalás alakhelyességre és felületi mikro-keménységre gyakorolt hatásának vizsgálata

Jelen tanulmányban az élettartamnövelő felületszilárdító eljárások közé tartozó felületvasalás technológiájának vizsgálatával, bemutatásával, valamint ennek a megmunkálási módnak a hengerességre és felületi mikro-keménységre gyakorolt hatásának elemzésével foglalkozom 42CrMo4 jelölésű ötvözet esetén. Az egyes jellemzők méréséhez egy köralak- és helyzethiba mérő-, valamint egy Vickers keménységet meghatározó berendezést használtam fel annak bizonyítására, hogy a felületvasalás előnyösen alkalmazható ezen az anyagminőségen.

Termikusan tesztelt generátor állórészek hengerességének vizsgálata

A tanulmány a generátor állórészek belső alakhibájának vizsgálatával foglalkozik, melyet magas és alacsony hőmérsékleten való tesztelési eljárás idéz elő. Ez a fajta meghibásodás befolyásolhatja a generátorok megfelelő működését, mivel a generátor egy másik alkatrészének, a rotornak a forgása során rezgések léphetnek fel. Kijelenthető, hogy ennek a hibának a hatása csökkenti a generátor teljesítményét. A publikáció célja annak vizsgálata, hogy a különböző tesztelési paraméterek úgy, mint hőmérséklet, tesztelési idő, az állórész el van-e látva rezgéscsillapító gyűrűvel vagy sem, milyen hatással bírnak. A kísérlet megtervezéséhez és végrehajtásához a teljes faktoriális kísérlettervezés módszerét alkalmaztuk. Az egyes elemek hengerességének mérése Taylor Hobson Talyrond 365 gyártmányú köralak- és helyzethiba-mérőberendezésen valósult meg. A mért adatokból speciális viszonyszámokat alkottam, annak érdekében, hogy meghatározzam azt a paramétertartományt, mely a legnagyobb mértékű deformációt okozza.

Power cycling and temperature endurance test of a GaN switching cell with substrate integrated chips

We present a reliability study of a half-bridge switching cell with substrate integrated 650 V GaN HEMTs. Power Cycling Testing with a ΔTj of 100 K has revealed thermo-mechanically induced failures of contact vias after more than 220 kcycles. The via failure mode of contact opening is confirmed by reverse-bias pulsed IV-measurements to be primarily triggered by a ΔTj imposed thermal gradient and not by a high Tj. The chip electrical characteristics, however, remained unaffected during Power Cycling. Furthermore, a High Temperature Storage test at 125 °C for 5000 h has shown no changes in the electrical performance of substrate integrated GaN HEMTs.

The effect of pH on synthesizing Ni-decorated MWCNTs and its application for Sn-58Bi solder

Nickel-decorated multi-walled carbon nanotubes (Ni-MWCNTs) were synthesized using a colloidal method and an electroless plating method to form Ni nanoparticles on the surface of MWCNTs. The Ni electroless plating process was optimized with solutions at various pH (5, 6, 7, and 8) levels. The Ni-MWCNTs fabricated at pH 7 show the most stable Ni nanoparticles on the surface of the MWNCTs. After optimization of the Ni plating process, the Ni-MWCNTs/Sn-58Bi composite solder were fabricated with varying contents of (0, 0.05, 0.1 and 0.2 wt%) Ni-MWCNTs. The experimental results show that Ni-MWCNTs enhance the mechanical properties of Sn-58Bi solder. The shear strength of Sn-58Bi solder improves by about 14% with 0.1 wt% Ni-MWCNTs. Furthermore, the microstructure evolution after a high temperature storage test shows that Ni-MWCNTs have an effect on grain refining and interrupt growth of the Intermetallic compound layer. The distribution of Ni-MWCNTs could be recognized with the results of EPMA.

A Study of the Intermetallic Compound Growth in Flip-Chip Packages under Thermal Loading

The intermetallic compound layers in solder bumps have the brittle feature and can easily fracture under thermal or mechanical loading. Therefore, the intermetallic compound is an issue for the fracture reliability of the solder bumps. In this work, the intermetallic compound growth before and after high temperature storage tests was investigated. The experiment results revealed that the solder bumps with nickel layers could reduce the intermetallic compound growth rate. The nickel layer, which was added in between Cu and SnAg for top solder bumps, was an important factor controlling the intermetallic compound thickness. It was hard to tell the intermetallic compound thickness at time zero; at the time of 147 hours, the intermetallic compound grew to 3.25 µm; at the time of 294 hours, the intermetallic compound grew to 5.25 µm. However, the solder joints were still in good condition.