Hybrid bonding of GaAs and Si wafers at low temperature by Ar plasma activation

High-quality bonding of 4-inch GaAs and Si is achieved using plasma-activated bonding technology.The influence of Ar plasma activation on surface morphology is discussed.When the annealing temperature is 300℃,the bonding strength reaches a maximum of 6.2 MPa.In addition,a thermal stress model for GaAs/Si wafers is established based on finite element analysis to obtain the distribution of equivalent stress and deformation variables at different temperatures.The shape varia-tion of the wafer is directly proportional to the annealing temperature.At an annealing temperature of 400℃,the maximum protrusion of 4 inches GaAs/Si wafers is 3.6 mm.The interface of GaAs/Si wafers is observed to be dense and defect-free using a transmission electron microscope.The characterization of interface elements by X-ray energy dispersion spectroscopy indi-cates that the elements at the interface undergo mutual diffusion,which is beneficial for improving the bonding strength of the interface.There is an amorphous transition layer with a thickness of about 5 nm at the bonding interface.The preparation of Si-based GaAs heterojunctions can enrich the types of materials required for the development of integrated circuits,improve the performance of materials and devices,and promote the development of microelectronics technology.

Effect of neutral polymeric bonding agent on tensile mechanical properties and damage evolution of NEPE propellant

Introducing Neutral Polymeric bonding agents(NPBA) into the Nitrate Ester Plasticized Polyether(NEPE)propellant could improve the adhesion between filler/matrix interface, thereby contributing to the development of new generations of the NEPE propellant with better mechanical properties. Therefore,understanding the effects of NPBA on the deformation and damage evolution of the NEPE propellant is fundamental to material design and applications. This paper studies the uniaxial tensile and stress relaxation responses of the NEPE propellant with different amounts of NPBA. The damage evolution in terms of interface debonding is further investigated using a cohesive-zone model(CZM). Experimental results show that the initial modulus and strength of the NEPE propellant increase with the increasing amount of NPBA while the elongation decreases. Meanwhile, the relaxation rate slows down and a higher long-term equilibrium modulus is reached. Experimental and numerical analyses indicate that interface debonding and crack propagation along filler-matrix interface are the dominant damage mechanism for the samples with a low amount of NPBA, while damage localization and crack advancement through the matrix are predominant for the ones with a high amount of NPBA. Finally, crosslinking density tests and simulation results also show that the effect of the bonding agent is interfacial rather than due to the overall crosslinking density change of the binder.

Carbon Fiber Breakage Mechanism in Aluminum(Al)/Carbon Fibers(CFs) Composite Sheet during Accumulative Roll Bonding(ARB) Process

We put forward a method of fabricating Aluminum(Al)/carbon fibers(CFs) composite sheets by the accumulative roll bonding(ARB) method. The finished Al/CFs composite sheet has CFs and pure Al sheets as sandwich and surface layers. After cross-section observation of the Al/CFs composite sheet, we found that the CFs discretely distributed within the sandwich layer. Besides, the tensile test showed that the contribution of the sandwich CFs layer to tensile strength was less than 11% compared with annealed pure Al sheet. With ex-situ observation of the CFs breakage evolution with-16%,-32%, and-45% rolling reduction during the ARB process, the plastic instability of the Al layer was found to bring shear damages to the CFs. At last, the bridging strengthening mechanism introduced by CFs was sacrificed. We provide new insight into and instruction on Al/CFs composite sheet preparation method and processing parameters.

3D reconstruction and defect pattern recognition of bonding wire based on stereo vision

Non-destructive detection of wire bonding defects in integrated circuits(IC)is critical for ensuring product quality after packaging.Image-processing-based methods do not provide a detailed evaluation of the three-dimensional defects of the bonding wire.Therefore,a method of 3D reconstruction and pattern recognition of wire defects based on stereo vision,which can achieve non-destructive detection of bonding wire defects is proposed.The contour features of bonding wires and other electronic components in the depth image is analysed to complete the 3D reconstruction of the bonding wires.Especially to filter the noisy point cloud and obtain an accurate point cloud of the bonding wire surface,a point cloud segmentation method based on spatial surface feature detection(SFD)was proposed.SFD can extract more distinct features from the bonding wire surface during the point cloud segmentation process.Furthermore,in the defect detection process,a directional discretisation descriptor with multiple local normal vectors is designed for defect pattern recognition of bonding wires.The descriptor combines local and global features of wire and can describe the spatial variation trends and structural features of wires.The experimental results show that the method can complete the 3D reconstruction and defect pattern recognition of bonding wires,and the average accuracy of defect recognition is 96.47%,which meets the production requirements of bonding wire defect detection.

Analysis of Bonding Properties of Corroded Reinforcement Concrete

In order to investigate the degradation of bonding properties between corroded steel bars and concrete,this study employs the half-beam method to conduct bond-slip tests between corroded steel bars and concrete after impressed-current accelerated corrosion of the steel bars in concrete.The effects of steel corrosion rate,steel bar diameter,steel bar strength grade,and concrete strength grade on the bonding properties between concrete and corroded steel bars were analyzed.The influence of different corrosion rates on specimens’bonding strength and bond-slip curves was determined,and a constitutive relationship for bond-slip between corroded steel bars and concrete was proposed.The results indicate that the ultimate bonding strength of corroded reinforced concrete specimens decreases with increasing corrosion rate.Additionally,an increase in corrosive crack width leads to a linear decrease in bonding strength.Evaluating the decline in adhesive properties through rust expansion crack width in engineering applications is feasible.Furthermore,a bond-slip constitutive relationship between corroded steel bars and concrete was established using relative bond stress and relative slip values,which aligned well with the experimental findings.

Toray develops hybrid bonding insulating resin and revolutionary polymer membrane

This year,Toray Industries,Inc.,announced that it has developed an insulating resin material for hybrid bonding(micro bonding).The material is based on Semicofine™and Photoneece™.These are high-heat-resistant polyimide coatings for semiconductor and display devices.The new material combines a conventional polyimide coating agent with the company’s processing and bonding technologies.It can enhance the yields and reliability of semiconductor devices in the hybrid bonding process,which entails bonding semiconductor chips with metal electrodes.Toray will push ahead with prototyping and providing samples to customers.It aims to obtain materials certification in 2025 and start mass production by 2028.

Transient liquid phase bonding of DD5 superalloy using a designed interlayer: microstructure and mechanical properties

Nickel based single crystal superalloy is currently widely used as the material for turbine blades in aerospace engines.However,metallurgical defects during the manufacturing process and damage during harsh environmental service are inevitable challenges for turbine blades.Therefore,bonding techniques play a very important role in the manufacturing and repair of turbine blades.The transient liquid phase(TLP)bonding of DD5 Ni-based single crystal superalloy was performed using the designed H1 interlayer.A new third-generation Ni-based superalloy T1 powder was mixed with H1 powder as another interlayer to improve the mechanical properties of the bonded joints.The res-ults show that,such a designed H1 interlayer is beneficial to the improvement of shear strength of DD5 alloy bonded joints by adjusting the bonding temperature and the prolongation of holding time.The maximum shear strength at room temperature of the joint with H1 interlayer reached 681 MPa when bonded at 1260℃for 3 h.The addition of T1 powder can effectively reduce holding time or relatively lower bond-ing temperature,while maintaining relatively high shear strength.When 1 wt.%T1 powder was mixed into H1 interlayer,the maximum room temperature shear strength of the joint bonded at 1260℃reached 641 MPa,which could be obtained for only 1 h.Considering the bonding temperature and the efficiency,the acceptable process parameter of H1+5 wt.%T1 interlayer was 1240℃/2 h,and the room tem-perature shear strength reached 613 MPa.

Interlaminar Bonding Performance of UHPC/SMA Based on Diagonal Shear Test

To evaluate various interlaminar bonding reinforcement techniques used for steel bridge decks,the UHPC surface was roughened with shot blasting(SB),transverse grooving(TG)and surface embedded stone(S),epoxy resin(E),epoxy asphalt(EA)and high viscosity high elasticity asphalt(HV)as interlayer bonding materials.In addition,a diagonal shear test was conducted using a self-designed diagonal shear jig.The effects of adhesive layer materials type,surface texture type,and different loading rates on the interlaminar bonding performance of UHPC/SMA combination specimens were investigated.The experimental study showed that the peak shear strength and shear modulus of the combined specimen decreased gradually with the decrease of thermosetting of the adhesive layer materials.The peak shear fracture energy of E was greater than that of HV and EA.The synergistic effect of the contact force generated by the roughing of the UHPC surface,the friction force,and the bonding force provided by the adhesive layer material can significantly improve the interlaminar shear performance of the assemblies.The power-law function of shear strength and shear modulus was proposed.The power-law model of peak shear strength and loading rate was verified.The shear strength and predicted shear strength satisfy the positive proportional functions with scale factors of 0.985,1.015,0.961,and 1.028,respectively.

Factor Structure and Measurement Invariance of the Japanese Version of the Mother-to-Infant Bonding Scale

Background: Bonding disorders affect the growth and development of infants. In Japan, the Japanese version of the Mother-to-Infant Bonding Scale (MIBS-J) is widely used for early detection of bonding disorders. Repeated use of a questionnaire has problems of reduced validity. In order to correctly detect bonding disorders at multiple time points, it is necessary to confirm the measurement invariance of the scale. Baba et al. reported that invariance of the MIBS-J factor structure could only be obtained by abridging the scale into three items. Purpose: The aim of this study was to 1) confirm the factor structure and measurement invariance of the MIBS-J between two measurement times and 2) to examine factors that can be used without being affected by measurement time in order to identify item that contribute to measure met invariance. Methods: We analysed the data of 1049 and 878 mothers with a neonate collected in two waves: 5 days (Wave 1) and 1 month postpartum (Wave 2). Exploratory and confirmatory factor analyses were conducted on the data randomly divided into two groups in each wave. Results: The three-item model (MIBS-J items 1, 6, and 8) was most accepted. Measurement invariance and structural invariance were confirmed in the model. This was consistent with Baba et al.’s model. Conclusion: The three MIBS-J items showed measurement invariance and structural invariance in Japanese mothers during 1 month postpartum.

Bonding mechanisms of SiO_(2) glass and 1060 Al by ultrasonic assisted active metal soldering process

In this work,the ultrasonic assisted active metal soldering of SiO_(2) glass and Al was successfully achieved using Sn-2Ti solder filler at a low soldering temperature of 250℃in ambient atmosphere.A nano-crystallineα-Al2O3 layer with the average thickness of 13.9 nm and a nano-crystalline R-TiO_(2) layer with the average thickness of 16.2 nm are formed at the interface of Al/Sn and SiO_(2)/Sn respectively because Al elements did not diffuse from Al alloy side to SiO_(2) side,which verified that a sono-oxidation reaction had occurred during the ultrasonic assisted active metal soldering process.The soldered butt joints exhibited an average tensile strength of 25.31 MPa.

Strength-ductility balance of AZ31 magnesium alloy via accumulated extrusion bonding combined with two-stage artificial cooling Author links open overlay panel

AZ31 Mg alloy with heterogeneous bimodal grain structure(smaller grain size of 5-20µm and coarser grain size of 100-200µm)was subjected to accumulated extrusion bonding(AEB)at 250℃combined with two-stage artificial cooling in this work,viz.local water cooling and artificial cooling.The microstructure developed consecutively as a result of discontinuous dynamic recrystallization(DDRX)for the AEBed samples.{10-12}tensile twinning also played an important role for the AEB with local water cooling at the initial extrusion stage in the container.Local water cooling could further reduce the DRXed grain size to~2.1µm comparing that without water cooling.And the grain growth rate was reduced by artificial cooling out of extrusion die.Under the combination of two-stage cooling,the fine DRXed grains at sizing band were almost retained with average grain size of~2.3µm after the sheet out of extrusion die,and the unDRXed grains with high residual dislocation density accumulation were also reserved.The tensile tests results indicated that a good strength-ductility balance with a high ultimate tensile strength(319 MPa vs.412 MPa)and fracture elongation(19.9%vs.30.3%)were obtained.The strength enhancement was mainly owing to the grain refinement and local residual plastic strain reserved by the artificial cooling.The excellent ductility originated from fine DRXed microstructure and ED-tilt double peak texture.

Characterization of Curing and Bonding of Wood with Adhesive Mixtures of Liquefied Wood and Hexamethylenediamine

Various crosslinking agents can be added to the formulations of natural-based adhesives for wood bonding in order to achieve better durability and higher strength of the formed joints.In the present study,the effect of hexamethylenediamine(HMDA)addition on the performance of liquefied wood(LW)adhesive for wood bonding is investigated.Differential scanning calorimetry showed the improved thermal stability and crosslinking of the LW adhesive with HMDA.The intensified presence of amide linkages(C–N bonds)was found in LW+HMDA with attenuated total reflection Fourier transform infrared spectroscopy.Analysis of the bonded joints using an automated bonding evaluation system showed that a higher press temperature resulted in stronger bonds for both types of adhesives.Moreover,the addition of HMDA to LW adhesive improved the bond strength of the joints and accelerated the crosslinking of the adhesive.However,with a tensile shear strength of(6.76±2.16)N×mm^(−2)(for LW)and(6.89±2.10)N×mm^(−2)(for LW+HMDA),both adhesives were found to be unsuitable for interior non-structural use.In addition,the acidity of LW resulted in relatively high wood failure(70%)in the adhesive joints tested.Improved crosslinking of LW with HMDA was reflected in improved resistance of LW+HMDA adhesive joints to water degradation.In conclusion,HMDA is a promising additive for improving the adhesive performance of LW adhesives.

Fluxless bonding with silver nanowires aerogel in die-attached interconnection

The electronic product has gravitated towards component miniaturization and integration, employment of lead-free materials, and low-temperature soldering processes. Noble-metal aerogels have drawn increasing attention for high conduction and low density. However,the noble metal aerogels with outstanding solderability were rarely studied. This work has successfully synthesized an aerogel derived from silver nanowires(AgNWs) using a liquid phase reduction method. It is found that the noble metal aerogels can be made into diverse aerogel preformed soldering sheets. The influence of bonding temperature(150-300 ℃), time(2-20 min), and pressure(5-20 MPa) on the joint strength of the AgNWs aerogel affixed to electroless nickel/silver copper plates were investigated. Additionally, the AgNWs aerogel displays almost the same shear strength for substrates of various sizes. In a word, this study presents a flux-free, high-strength, and adaptable soldering structural material.

Estimation and Analysis of Structural Responses of Asphalt Pavement Using Interlayer Contact Bonding Model

The interlayer contact condition of asphalt pavement has a significant impact on stress transfer and energy dissipation with adjacent layers,so a model considering the bonding condition of adjacent layers is introduced for evaluating the structural response of asphalt pavement.The pavement structure,the material characterization with temperature,the interlayer contact bonding model,the types of bond failure,and the prediction method of pavement life are described in detail.Results show that the transversely tensile strains at the top of asphalt pavement under the condition of high temperature were easy to cause the top-down cracking outside the edge of the dual tire.The bonding failure has a significant influence on strains at the bottom of the surface course with the condition of high temperature,especially,the longitudinally tensile strains would increase obviously as the disengaging area between the surface course of asphalt pavement and the base layer increases.Finally,it is proved that the surface course is vulnerable to form deformations and cause damage under the combined action of low speed and high temperature.

Bonding, Structure and Uses of Metals

This work briefly describes some of the different features of groups of metals.It highlights recent progress in research into metals.It details the structures and defects in solid metals.The common theories of metals including the free electron theory,band theory,the ions in a sea of electrons model and the soft sphere model are discussed and their merits are considered.It describes distinctions between the bonding in metals and inter-metallic compounds.It shows the influence of bonding on the properties of metals and alloys and provides a summary of tradition and newer uses of metals.

Effect of Mechanical Surface Treatment on the Bonding Mechanism and Properties of Cold‑Rolled Cu/Al Clad Plate

In the case of valuable cold-rolled Cu/Al clad plates,billet surface treatment before rolling is a significant process that can affect the bonding efficiency and quality.While the current studies primarily focus on the influence of rolling parameters,insufficient attention has been paid to surface treatment.In this study,the effects of mechanical surface treatment on the bonding mechanism and bonding properties of cold-rolled Cu/Al clad plates were investigated.The results showed that different mechanical surface treatments have significant effects on the surface morphology,roughness,and residual stress.In addition,the effect of surface mechanical treatment on bonding quality was also observed to be critical.When the grinding direction was consistent with the rolling direction(RD),the bonding quality of the Cu/Al clad plates was significantly improved.After surface treatment along the RD for 20 s,the Cu/Al clad plates showed the highest shear strength(78 MPa),approximately four times as high as that of the unpolished samples.Simultaneously,the peel strength of this process was also significantly higher than that achieved via the other processes.Finally,on the basis of the surface morphology,roughness,and residual stress,the effect of surface treatment on the bonding mechanism and bonding properties of Cu/Al clad plates was analyzed.This study proposes a deeper understanding of the bonding behavior and bonding mechanism for cold rolled clad plates processed via mechanical surface treatment.

When insulating polymers meet conjugated polymers:the noncovalent bonding does matter

Insulating polymers are characterized by a predominantlyσ-covalent structure,which localize electrons in the atoms and exhibit dielectricity.Insulating polymers typically adopt a more linear and extended conformation,as the repeating units are connected by single covalent bonds,resulting in a relatively straight and extended chain structure.For most insulating polymers,the contour length(L_(c))is significantly larger than their persistence length(Lp)due to the rotation of C−C single bonds(Fig.1(a)).Consequently,this leads to a flexible,random-coil chain conformation.This structural feature contributes to the great mechanical durability and resistance to crack initiation during stretching or bending processes.In contrast,conjugated polymers possess aπ-conjugated molecular structure,allowing electron mobility along the main chain,called delocalization,which imparts semiconducting properties[1,2].The presence of rigid,alternating single and multiple bonds results in comparable Lc and Lp,thereby yielding a stiff or semi-flexible conformation(Fig.1(b))[3,4].As a consequence,most conjugated polymers are prone to fracture under low strain levels(<10%)[5−7].

Early Debonding Detection of Rebar-Concrete Interface due to External Loading Utilizing AC Impedance Spectroscopy

A novel method for detecting early damage at the steel-concrete interface due to external loading based on AC impedance spectroscopy technology was proposed.Firstly,alkali pretreatment was introduced to ensure the accuracy and repeatability of the AC impedance test.Secondly,the AC impedance spectroscopy between the steel bar and concrete surface of different bonding positions was tested,and then the physical quantities reflecting the bonding damage condition were obtained by equivalent circuit fitting.Theoretical debonding position calculation and AC conductive structure analysis indicate that the change of interface resistance and interface capacitance can seize the development of bonding damage during the loading process.As the interface damage develops,obvious changes in interface resistance and interface capacitance are observed,and they cannot be recovered after unloading.

Chemical bonding of perovskite LaFeO_(3) with Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2) to moderate anion redox for achieving high cycling stability

Oxygen anion redox reaction provides a high theoretical capacity for Li-rich manganese-based cathodes.However,irreversible surface oxygen release often results in further oxygen loss and exacerbates the decomposition of the electrolyte,which could reduce the capacity contribution from the anionic redox and produce more acidic substances to corrode the surface of the material.In this paper,the surface oxygen release is suppressed by moderating oxygen anion redox activity via constructing chemical bonds between M(M=Fe and La)in LaFeO_(3)and surface oxygen anions of Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2).The constructed interface layer stabilizes the surface lattice oxygen and retards the electrolyte from being attacked by the nucleophilic oxygen generated in the process of oxygen release,as evidenced by Differential Electrochemical Mass Spectrometry(DEMS)and X-ray Photoelectron Spectroscopy(XPS)detections.Moreover,in the charge and discharge process,the formed FeF_(3),located at the cathode electrolyte interfacial layer,is conducive to the stability of the cathode surface.The modified Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2)electrode with 3 wt%LaFeO_(13)exhibits a high specific capacity of 189.5 mA h g-at 1C(200 mA g^(-1))after 150 cycles with capacity retentions of 96.6%,and 112.6 mA h g^(-1)(84.7%)at 5C after 200 cycles higher than the pristine sample.This study provides a rational design chemical bonding method to suppress the oxygen release from the cathode surface and enhance cyclic stability.

Shear Bond Strength of Different Types of Cement Used for Bonding Band and Loop Space Maintainer

Purpose: The present study aimed to evaluate the effects of thermal aging on the shear bond strength of three different types of cement used to retain band and loop space maintainers cemented on extracted human permanent molar teeth. Methods: A total of 66 newly extracted permanent molars were used in this study. Eighteen teeth were used as a control and did not undergo thermal aging (six per group). All sample teeth were randomly divided into three groups: KetacCem, RelyX Luting Plus, and RelyX Unicem 2. After bonding procedures, all experimental groups undergo thermal aging. The shear bond strength of all samples was conducted using the Ultratester machine. Findings were statistically analyzed using the ANOVA and Turkey’s post hoc tests. Results: Among the examined groups, Ketac Cem presented with the highest recorded shear bond (11.4 MPa), while RelyX Luting Plus showed the lowest (3.2 MPa). The control groups recorded the highest shear bond strength compared to all examined groups;Ketac Cem showed the highest shear bond strength (12.8 Mpa), and RelyX Luting Plus had the least recorded reading (5.4 Mpa). Conclusion: Within the limitation of the present study, there was a statistically significant difference between the examined groups;Ketac Cem showed a higher shear bond cement than RelyX luting Plus and RelyX Unicem.