Lid Material Research Articles

AN ACCESSIBLE GLOVE BOX PROJECT FOR PROCEDURES THAT REQUIRE INERT CONDITIONS

An inert atmosphere is, in some cases, important for the performing of experiments where substances are toxic and/or sensitive to oxygen. However, the high cost and accessibility of an equipment to work under these conditions, results in the fact that most laboratories do not have this kind of equipment. In this paper, we present a simple and efficient project to build a cheap glove box for processes that require an inert atmosphere. The proposed glove box is made using medium density fiberboard (MDF), an acrylic lid, hinges, air valves, PVC gloves and other materials that can be found easily in local stores or on the internet. Tests to verify the quality of the nitrogen atmosphere were performed using the lighter test and niobium pentachloride (NbCl5), which is a moisture/oxygen sensitive material. The results demonstrated that the equipment is able to maintain an inert atmosphere for several hours, does not permit lighter to function and maintains the NbCl5 stable.

On the influence of lid materials for flip-chip ball grid array package applications

Autonomous driving is a key vehicle capability for future mobility solutions that relies on the reliability of its high-performance vehicle computer. As for any electronics for automotive applications, thermal management is a crucial point. A very extensively employed approach for improving heat removal is the usage of heat spreaders in the form of a package lid, especially for flip-chip applications. The usage of a lid in flip-chip ball grid array (BGA) packages improves heat removal based on the heat spreading capabilities of the lid, and reduces package warpage, since with a lid the package becomes stiffer. However, adding a lid also increases stresses at solder interconnects. When selecting a material for the lid, the most intuitive criterion is to focus on the material’s thermal conductivity. Sometimes overlooked, the coefficient of thermal expansion (CTE) of the lid also plays an important role regarding package warpage and reliability of thermal interface materials (TIM) as well as solder interconnects, such as solder bumps. This work focuses on the influence of different lid materials at package level for flip-chip applications. Consequently, the influence of three alternative materials is investigated and compared to the performance of a standard copper lid. For the quantification of the effects, a validated finite element model of a flip-chip package is presented, with the thermo-mechanical performance of the studied lid materials validated based on package warpage, peel strains and plastic strain energy density at the bumps, as well as on peel and shear strains at the TIM.

Advanced multi-step brazing for fabrication of a divertor heat removal component

The advanced fabrication method named advanced multi-step brazing (AMSB) has been developed for fabrication of a tungsten (W)/copper alloy divertor heat removal component in a fusion reactor. The principle of AMSB is repetitive application of the advanced brazing technique (ABT). The ABT was originally developed in our previous work for jointing of W and oxide dispersion strengthened copper alloy (ODS-Cu: GlidCop®) with the BNi-6 (Ni-11%P) filler material. The special feature of the AMSB is that the leak-tight joint of GlidCop® (GlidCop®/GlidCop®) and of stainless steel (SUS) and GlidCop® (SUS/GlidCop®) can be realized by application of the ABT. Therefore, the AMSB enables production of a leak-tight sealing structure with the appropriate lid material such as GlidCop® or SUS for a pre-processed rectangle-shaped cooling flow path channel. The rectangle-shaped cooling flow path channel has an advantage regarding its heat removal capability. Another special feature of the AMSB is that the physical properties of the AMSB joint has strong tolerance against the repetitive brazing heat cycle. Thus, repetitive application of the ABT does not cause any undesired effects on the leak tightness of the GlidCop®/GlidCop® and the SUS/GlidCop®. The new AMSB type component with the rectangle-shaped fluid flow path and the V-shaped staggered rib structure were successfully produced; therein a pre-processed rectangle-shaped cooling flow path channel was sealed with a GlidCop® and SUS lid structure with leak-tight conditions. The component showed excellent heat removal capability under reactor-relevant conditions with ∼30 MW m−2.

Optimal Lid Design Parameters for Reducing Warpage of Flip-chip Package

Abstract Flip-chip packages are usually integrated with a stiffener ring (SR) or lid to reduce the warpage which usually consumes considerable substrate space and hence, reduce the effective area available for placement of dies and passive components. With chip module size growing in modern semiconductor devices (e.g., to enable heterogeneous integration of different functional dies), there is a need to reduce the substrate area occupied by the lid while also reducing the package warpage to an allowable value. This requires an accurate understanding of how different parameters of the lid affect the warpage of the package. Here, for a large package, effects of the lid design variables, including (i) SR versus lid, (ii) lid foot width, (iii) lid plate thickness to foot width ratio, (iv) lid material, and (v) thickness of thermal interface material (TIM) connecting the die and the lid, on the warpage have been analyzed using the 3-D elasticity theory and the finite element method. It is found that for a given value of the lid plate thickness to foot width ratio, the warpage of the package is a non-monotonic function of the foot width and is not necessarily minimum for the maximum value of the foot width. The effects of lid material and TIM thickness are found to depend upon the foot width. Various results presented here should provide packaging engineers with guidelines to obtain optimal lid designs that minimize the package warpage while offering noticeable saving in the effective substrate area.

Strain localization in copper canister FSW welds for spent nuclear fuel disposal

Spent nuclear fuel disposal in copper canisters in a deep geologic repository is planned in Finland and Sweden. The purpose of the copper shell is to perform as a ductile corrosion barrier to prevent radioactive substances from leaking into the environment. Therefore, the most important property of the copper shell, besides the good corrosion resistance, is its ductility. The copper canisters are sealed by friction stir welding (FSW), which results in strong welds when compared to the base materials, but the microstructural heterogeneity introduced by the welding may also lead to strain localization. Thus, the strain localization behavior of two different copper canister welds was studied by tensile tests in combination with digital image correlation (DIC). The main difference between the welds is the utilization of shielding gas to reduce oxidation during welding. The shielding gas improves the stability of the welding process, as well as reduces the number of oxide particles in the welds. It is known, that oxide particles are detrimental in copper in the presence of hydrogen. Therefore, the two welds were also thermally hydrogen charged to study hydrogen trapping in the weld material. Thermal desorption measurements (TDS) show that considerable hydrogen uptake occurs in the weld oxide zone, but it did not compromise the ductility of the copper welds in these tests. However, the DIC tests indicate considerably earlier strain localization on the retreating side of the new weld, welded with the shielding gas. This is attributed to differences in the initial state of the lid materials.

Microcontainers for protection of oral vaccines, in vitro and in vivo evaluation

Oral vaccines are highly desirable due to simple logistics, mass vaccination potential and for mucosal immunity. Subunit vaccines are preferred due to high safety, but are inherently difficult to deliver orally, thus providing motivation for the use of advanced oral delivery systems. Polymeric devices in micrometer size (microcontainers) were tested here for this purpose. Microcontainers were loaded with a vaccine consisting of spray dried cubosomes with OVA and Quil-A, and coated with a pH-sensitive lid for oral delivery to C57Bl/6 mice. The microcontainers were explored in vitro and in vivo for their potential as oral vaccine delivery system in an oral prime-boost setting and as an oral booster after a subcutaneously injected prime. The residence time of microcontainers in the small intestine was less than one hour. Eudragit® L100–55 was therefore chosen as lid material on the microcontainers as it remained stable in vitro at pH 4.7, which simulated the maximal pH of the stomach, and allowed release of the cubosomes within 30–60 min at pH 6.6, which simulated the mean pH of the distal half of the small intestine. In vitro small angle X-ray scattering showed that cubosomes dissolved in small intestinal fluid when not confined in microcontainers but when loaded into microcontainers they were released as hexosomes. However, while microcontainers could protect and release particles with OVA and Quil-A within relevant time frames in vitro, an immune response was not elicited in vivo after oral administration. Nonetheless, some effect was observed when the microcontainers were used to deliver oral boosters following a subcutaneous prime. This work indicates that oral vaccination with subunit vaccines has potential when combined with a parenteral prime and that oral delivery systems like microcontainers may be used to increase the potency of vaccines with low oral immunogenicity.

Analisis Profil Iklim Mikro Pada Budidaya Cabai Rawit (Capsicum Frutescens L) Menggunakan Bahan Sungkup Plastik, Paranet, dan Kombinasi

The hood is an alternative to overcome the high intensity of sunlight. In this study the type of containment material treatment can be divided into 3 types of containment material, namely the type of plastic lid material, paranet and combination. For microclimate measurements, a temperature and humidity meter and a light meter are used. Microclimate measurements were carried out at 12.00 WITA, on cayenne pepper from 7 days to 35 HTS. Micro climate data analysis is done by interpolation to obtain the profile contour lines. The results of the study showed that there were different shapes and distribution of different micro-climate profile contours, especially in light intensity. At air temperature and air humidity can not obtain contour lines, because the results of the data from the research conducted are not much different. Plant growth rates in each treatment showed different productivity. In this type of paranet lid material shows better results compared to the type of plastic hood and combination material. In this type of paranet lid material produces an average dry weight of 247.9 grams.
 Keywords: hood type material, cayenne pepper plant, microclimate.

A new hermetic sealing method for ceramic package using nanosilver sintering technology

High reliable packaging materials are needed for electronics when they work at harsh environments. Among which, the nanosilver material has been widely studied and applied in power electronics due to its low processing temperature and high reliability. This paper investigates the bonding properties of nanosilver sintered hermetic cavity. There are two kinds of lids used in this study, including copper lid and silicon lid. The X-ray and C-Mode Scanning Acoustic Microscopy (C-SAM) results revealed that delamination tended to happen in Cu lid sintered cavity as the recovery of deformed Cu lid was hindered by sintered dense Ag layer. However, no delamination or cracks were found in Si lid sintered cavity. Finite element analysis (FEA) method was used to investigate the effects of lid materials on the stress distribution of lid. The results indicated that the Cu lid sintered cavity showed a much higher stress than the Si lid sintered cavity under the sintering parameters of 250°C and 10MPa. There is no obvious change in the stress distribution areas on Cu lid with the increasing of pressures from 5 to 30MPa. However, the distribution area of stress on Si lid expanded obviously only when the sintering pressure increased to 30MPa. With the increase of sintering pressures from 5 to 30MPa, the maximum stresses on Cu lid are almost the same, while increasing trend was found on Si lid.

Proton on Metal Fission Environments in an IC Package: An RHA Evaluation Method

A study of proton-induced destructive SEE (DSEE) from Au-plated lid fission fragments has been expanded. Seventeen additional lid materials (Z =26–83) are studied. Lead (Pb) produced a higher sensitivity than seen in previous work with gold (Au), raising new concerns of SEE enhancement due to die-proximate Pb-based solder in flip-chip package designs. New analysis has allowed generalized RHA rules to be developed.

Correlation of Ship Sanitation with Cockroach Density on Motor Vessel Docked in Port of Tanjung Perak Surabaya

Abstract: Based on data from Port Health Offi ce Class I Surabaya in 2012, 42 (1.66%) of 2.521 ship that were inspected was found vectors. Sanitation assessment data were found cockroach in July 2015, 9 (4.20%) of 214 ships, in August 15 (8.02%) of 187 ships, and in September 16 (8.88%) of 180 ships. Meanwhile Kepmenkes 431/2007 states that all water transportation have to be clean from vector and rodent. The objective of this study was to analyze correlation between ship sanitation and cockroach density. The design of this study was cross sectional. Samples was 30 ship that were docked at Port of Tanjung Perak Surabaya in October 2015. Sampling method was using accidental sampling. Data were obtained by questionnaire and observation Data were analyzed with Spearman correlation test. The result showed that 40.00% had high risk of health disorder and 91.67% of 40.00% was found high cockroach density There was a signifi cant correlation between ships sanitation and cockroach density. Not only all bins were not equipped with lid and water resistant materials but also poor personal hygiene of food handlers. It can be concluded that there was a correlation between ship sanitation and cockroach density. It is suggested to improve and maintain ship sanitation by equipping all of bins with lid and water resistant material and by increasing the personal hygiene of food handlers.Keywords: vessel sanitation, cockroach density, motor vessel

Effects of packing materials on the sensitivity of RadFET with HfO2 gate dielectric for electron and photon sources

The radiation sensing field effect transistor (RadFET) with SiO2 gate oxide has been commonly used as a device component or dosimetry system in the radiation applications such as space research, radiotherapy, and high-energy physics experiments. However, alternative gate oxides and more suitable packaging materials are still demanded for these dosimeters. HfO2 is one of the most attractive gate oxide materials that are currently under investigation by many researchers. In this study, Monte Carlo simulations of the average deposited energy in RadFET dosimetry systems with different package lid materials for point electron and photon sources were performed with the aim of evaluating the effects of package lids on the sensitivity of the RadFET by using HfO2 as a gate dielectric material. The RadFET geometry was defined in a PENGEOM package and electron–photon transport was simulated by a PENELOPE code. The relatively higher average deposited energies in the sensitive region (HfO2 layer) for electron energies of 250 keV–20 MeV were obtained from the RadFET with the Al2O3 package lid despite of some deviations from the general tendency. For the photon energies of 20–100 keV, the average amount of energy deposited in RadFET with Al2O3 package was higher compared with the other capped devices. The average deposited energy in the sensitive region was quite close to each other at 200 keV for both capped and uncapped devices. The difference in the average deposited energy of the RadFET with different package lid materials was not high for photon energies of 200–1200 keV. The increase in the average deposited energy in the HfO2 layer of the RadFET with Ta package lid was higher compared with the other device configurations above 3 MeV.

Stress and Strain Modeling of Low Temperature Cofired Ceramic (LTCC) Seal Frame and Lid

Low temperature cofired ceramic (LTCC) is established as an excellent packaging technology for high reliability, high density microelectronics. LTCC multichip modules (MCMs) comprising both ‘surface mount’ and ‘chip and wire’ technologies provide additional customization for performance. Long term robustness of the packages is impacted by the selection of seal frame and lid materials used to enclose the components inside distinct rooms in LTCC MCMs. An LTCC seal frame and lid combination has been developed that is capable of meeting the sealing and electromagnetic shielding requirements of MCMs. This work analyzes the stress and strain performance of various seal frame and lid materials, sealing materials, and configurations. The application for the MCM will impact selection of the seal frame, lid, and sealing materials based on this analysis.

Quality and Reliability of 3D High-Performance Heterogeneous Integration through Die Stacking

This paper studies package reliability for the industry's first heterogeneous Stacked Silicon Interconnect (SSI) FPGA family (3D integration) delivering up to 2.78 Tb/s transceiver bandwidth. Each device is packaged on a low-temperature co-fired ceramic (LTCC) package for optimal signal integrity. 3D thermal-mechanical simulations are built to analyze package warpage, low-k stresses, microbumps and C4 bumps fatigue as well as BGA ball reliability. Different substrate sizes and designs, lid designs, lid materials and C4 bump underfill materials are investigated in order to optimize package reliability. LTCC ceramic package reduces fatigue in C4 bumps when increasing the risk for BGA balls to fail in thermal stressing. Hence, lid design and C4 bump underfill material are optimized to increase fatigue life for BGA balls. Simulation results indicate heterogeneous stacked-silicon (3D) integration is a reliable method to build very high-bandwidth multi-chip devices that exceed current monolithic capabilities.

Fluxless Hermetic Lid Sealing Using Electroplated Sn-Rich Solder

A new fluxless hermetic sealing technique using electroplated Sn-rich soft solder is reported. Specific glass (SCG72) is chosen as lid material to seal alumina packages. It has nominal coefficient of thermal expansion of 7 ppm/deg C, close to that of alumina. Alternatively, sapphire can also be used as the lid material. A thick Sn layer is plated over the Cr/Au patterned glass wafer, followed immediately by thin Au layer. This outer Au layer prevents the inner Sn from oxidation. In bonding, the glass lid is placed over the package rim which has a metallization structure of W/Ni/Au. The fluxless sealing process is performed in vacuum (50 millitorrs) to suppress tin oxidation. Compared to bonding in air, the oxygen content is reduced by a factor of 15 200. Fluxless bonding is valuable in many hermetic sealing applications such as microelectromechanical systems (MEMS), sensors, photonic devices, and imaging devices. Nearly void-free sealed joints are achieved with Sn-rich composition. Helium leakage tests are performed to evaluate hermetic quality. Scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX) is used to evaluate the composition and microstructure of the sealing joints. The results show how the Sn-rich solder reacts with the W/Ni/Au on the package. This new sealing process can be applied to nearly all devices and packages that require hermetic sealing.

Effect of Lid Materials on the Solder Ball Reliability of Thermally Enhanced Flip-Chip Plastic Ball Grid Array Packages

This research studied the thermal fatigue life for eutectic solder balls of thermally enhanced flip-chip plastic ball grid array (FC-PBGA) packages with different lid materials under thermal cycling tests. Three FC-PBGA packages with different lid materials, i.e., Al, AlSiC, and Cu, were utilized to examine the lid material effect on solder ball reliability. The cyclic stress/strain behavior for the packages was estimated by using the nonlinear finite element method. The eutectic solder was assumed to be elastic-plastic-creep. The stable stress/strain results obtained from FEM analysis were utilized to predict the thermal fatigue life of solder balls by using the Coffin-Manson prediction model. Simulation results showed that the fatigue life of the FC-PBGA package with a Cu lid was much shorter than FC-PBGA packages with other lid materials. The relatively shorter fatigue life for the FC-PBGA package with a Cu lid was due to the complex constrained behavior caused by the thermal mismatch between the lid, substrate and the printed circuit board. The difference was insignificant in the fatigue lives between the package with an Al lid and the conventional package.

Benzocyclobutene (DVS-BCB) polymer as an interlayer dielectric (ILD) material

Polymer films of DVS-BCB (CYCLOTENE TM 5021) exhibit a combination of material and processing properties which make them an attractive low k interlayer dielectric (ILD) material for integration into IC manufacturing processes. Key DVS-BCB film properties include isotropic dielectric constant (2.65 @ 1 MHz); equilibrium moisture absorption (< 0.2% @ 25°C and 81% RH); high purity (< 10 ppb individual metals concentrations); T g > 350°C; low alpha-particle emission rates. The DVS-BCB films are easily produced using simple resist spin track equipment and are subsequently cured without generation of corrosive or volatile by-products under anaerobic conditions (less than 100 ppm oxygen). Films are completely cured for typical processing conditions at 250°C for 1 h or as rapidly as 30 s at 325°C. DVS-BCB has been demonstrated to fill 0.20 μm gaps at 5:1 aspect ratios. Fully cured films exhibit greater than 95% degree-of-planarization for isolated feature widths of 20 μm and less; 80% for widths between 20 μm and 100 μm. Currently, the acceptance of DS-BBC is challenged by today's thermal requirements of greater than 400°C for CD-W via/plug and post device/contact anneals. The development of moderate temperature metal deposition processes and reduced final device anneal temperatures would enable implementation of DS-BBC as an LID material with the realization of its low dielectric constant, excellent gap-fill and other attractive features.

Neutron production measurements from an LiD fusion plate using an NE-213 detector

To characterize the high energy neutron production from an LiD plate constructed at Texas A&M University, measurements and calculations were performed. Two types of measurements were used to substantiate the high energy neutron flux. One used an NE-213 detector system to measure the high energy neutron production from the LiD plate and the other employed foil activation to measure the neutron flux entering the irradiation cell. A new code, FERDNA, was produced by not only converting the original unfolding FERD code to Microsoft FORTRAN but also embellishing the code with several subroutines to perform integration over energy ranges specified by the user. Raw pulse-height distributions from an NE-213 detector were directly transferred from an MCA to a MacIntosh where FERDNA was executed. The LiD plate was designed and constructed by considering (1) neutron production due to 6 Li(n, α) 3 T reactions and subsequent T-D or T-Li fusion as the tritons slow down and (2) the escape probability of tritons from the LiD material. This allowed the needed 6 Li enrichment and thickness of the plate to be selected. The number of high energy neutrons produced per thermal neutron incident upon the LiD plate was measured as 1.03×10 −4 ±8.5% n/n th .

マイクロパラレルシーム接合法とその接合機器の開発 ＩＩ セラミックパッケージの表面温度とシーム接合条件

It is required, as an indispensable condition, to secure the specified hermeticity as well as to restrain temperature rise at the minimum and prevent deterioration of an element inside the package from thermal effect during hermetic sealing process of a ceramic package for which high reliability is demanded. For this reason, Thermal Video System, which is able to detect JR thermal image in real-time, was used in this experiment to observe progressive change in surface temperature distribution of a ceramic package during Micro Parallel Seam joining process. Also, the relationships between various seam joining conditions and surface temperatures obtained were studied, and some conditions were established to restrain package temperature rise while maintaining her meticity of 10-8 atm cm3/s which is defined as the criteria for acceptance/reject of seam joining quality.The results obtained are as follows.(1) Package surface temperature distributions were first shown so that two high temperature areas (hot spots) appeared in the vicinity of left and right roller electrodes immediately upon start of current flow, and temperature continued to rise toward the center of lid thereafter as isothermal ring expanded from those hot spots which were to be the center. Such status continued for approximately 70% of total joining time and finally the center of lid reached the highest temperature.(2) In order to restrain package temperature rise;(a) Roller electrode with a greater taper angle should be used.(b) As for seam joining conditions, electrode force and current should be selected as small as possible and joining speed faster within the range that specified herrneticity can be maintained.(c) Lid with plating tends to cause temperature rise, especially when plating material, of which melting point is lower than that of lid material itself, used.(3) Also, voltage between roller electrodes, current, resistance and contact width between the lid and roller electrode were discussed in relation to temperature rise of ceramic package.

接合界面におけるめっき層の存在と接合性への影響 マイクロパラレルシーム接合法及び接合機器の開発 １

Among several hermetically sealing methods, we studied experimentally on Micro-Parallel Seam Joining (MPSJ) used for hermetic seal of high reliable ceramic package for semiconductor devices, particularly paying attention to the relationship between plated materials on the package and lid and its seam joining characteristics to verify the MPSJ phenomena.Results obtained are summarized as follows.(1) Cracks were observed on the ceramic substrate immediately after seam joining, that was considered to be caused by the difference in thermal expansion coefficient in the case where austenitic stainless steel, SUS-316 lid was used. Therefore, it will be required to use Fe-Ni-Co Alloy, KOVAR as a lid material which has a similar thermal expansion coefficient with the ceramic substrate (Al2O3).(2) Seam joined area was consisted of both a mutually diffused layer at the joining boundary formed by plating material for the lid and seal frame and the fillet formed around the circumferential edge of the lid. No molten layer of both base materials existed.(3) The main reason for the paragraph (2) is the fact that density of heat generation at the joining boundary will decrease because of current path area expands due to softening and fusion of plating material concurrent with the current flow. Therefore, both the contact resistance between the lid and roller electrodes and inherent resistance of the lid will be the majority for heat generation source. Consequently, lid and seal frame will be joined in the form of brazing under pressure of plating material.(4) From the above results, it has been verified that plating material for the lid and seal frame plays an important role to secure specified hermeticity in the case of hermetic sealing of ceramic packages by MPSJ.

Use of sterically stabilized polymer colloids as electrostatically‐based liquid developers

AbstractLiquid immersion development (LID) of a latent electrostatic image has become established as an important alternative to dry toning during the past decade. In this development method, a charged, colloidally stable colored particle that is dispersed in a dielectric fluid undergoes electrophoresis under the influence of an applied field. These particles then neutralize a latent electrostatic image of opposite polarity, which resides on either a photoreceptor drum or on dielectric paper. This results in a hard copy of the latent image being obtained. In this paper we outline the physicochemical properties that are demanded of a liquid toner and describe an alternative approach to the preparation of a LID materials package. This new approach utilizes a nonaqueous polymer colloid as the vehicle, which when colored and charged, gives a LID toner. The advantage of nonaqueous dispersions is that the steric stabilizer is irreversibly attached to the particle. Since desorption of the stabilizer is not a problem, these materials are colloidally stable for an indefinite period of time. The particles were colored using both dyes and pigments. While neither approach was entirely satisfactory, the feasibility of coloring such particles was demonstrated. A positive charge was imparted to the particles by specific adsorption of the cation of a metal soap at the polymer–fluid interface. It was found that these experimental LID toners were able to develop a latent electrostatic image in a commercially available printer with the image being well fixed to the paper. While this approach has not been optimized, it appears to be an attractive route for preparing novel LID developers.