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[250430 NY S U draft.pdf](https://mdr.nims.go.jp/filesets/58748383-b9cd-4151-abc7-a9fcf758de18/download)

## Creator

[Akitsu Shigetou](https://orcid.org/0000-0001-7054-3674)

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[In Copyright](http://rightsstatements.org/vocab/InC/1.0/)

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[Surface Modification for High-Reliability and Multi-Functional Hybrid Interconnections](https://mdr.nims.go.jp/datasets/cd2921d4-af74-462b-a335-27724c2e0637)

## Fulltext

250430 NY S UnivSurface Modification for High-Reliability and Multi-Functional Hybrid InterconnectionsAkitsu ShigetouPrincipal Researcher, Team Leader,Smart Interface Team,Research Center for Materials Nanoarchitectonics (MANA),National Institute for Materials Science (NIMS)Concurrently: Visiting Professor, the University of TokyoGuest Seminar @ State University of New York at Binghamton2025/04/3001OutlinePoints of my talk:p Importance on surface/interface design to create functionsp Bonding & debonding in single process1. Research backgrounds︓1.1. Interfaces for Cutting-Edge Applications1.2. Essential Surface/Interface Characteristics2. Lineage to Low-Temp, Non-Vacuum, Reliable Hybrid Bonding2.1. Direct Bonding Using High Vac (1990s)2.2. Half Non-Vac Process (early 2000s)2.3. VUV-Based Non-Vac Process (around 2007~)2.4. New VUV-Based Process (around 2010~)3. For ”Cradle to Grave" Tech: Bondability and Debondability3.1. Trigger of ”Solid-State Debonding”3.2. Process Design3.3. Bondability & Debondability4. Summary 12Before Getting StartedHybrid materialsNovel interfacialstructuresMtr. 1Mtr. 2Hybrid-bonded layersCost-effective assemblyMust be bonded in a compatible method to different industrial fieldsApplication-oriented integration of discrete layers… also to fabrication of various structural partsSimple solid-state debonding for: - temporary bonding- urban mine recycling- Green fabrication  etc. Easy triggerSolid-State!2Team for surface and interface design to create multiple functionsp A. Shigetou (Team leader)p Two post-doctoral researchers from India and Chinap Two Ph. D. candidates from Taiwanp 3 technicians0. What we are全く異なる学理でアプローチ334Co-supervision of doctoral students with overseas partner universitiesInternational Cooperative Graduate ProgramAs of August 1st, 2022• NIMS supports living expenses of graduate students in Tsukuba for up to 12 months in the course of their Ph.D. study• Partner universities support travel expenses of their studentsInstitute of Materials ScienceMoscow State Univ.Budapest Univ. Economic & TechnologyFlinders Univ.Universiti TeknologiMalaysiaAnna Univ.NationalTaiwan Univ.NationalTsing Hua Univ.Chulalongkorn Univ.Warsaw Univ. of TechnologyNorwegian Univ. of Science and TechnologyUniv. of Pardubice Institut Teknologi BandungUniversiti Kebangsaan MalaysiaIndian Institute of Technology HyderabadIndian Institute of Technology GuwahatiNationalCheng Kung Univ.National Yang MingChiao Tung Univ.Seoul National Univ.Univ. of Caen NormandyIndian Institute of Technology (BHU)Asia                    15Europe                10North America      4Oceania                1 --------------------Total 30 University of the Philippines5561. Research Backgrounds67Transparency, conductivity, carrier/electron mobility...The better tunability of interfaces the better system performancesSemi direct-bonded interfaces of (Left)PDMS and (Right) multi-layered graphene:Shigetou et al., IEEE NANO 2012 etc.Adhesion, responsivity, bandgap, diffusivity, reliability...(Up) Quantum well IR photodetectorsand (down) semi direct-bonded GaN/ SiC interface: Shigetou et al., ECTC2015 and Miyazaki et al., 4th A3MetaMtr. Forum 2019, respectively.Direct-bonded Be-V for neutron excitation target40mmAtomic scaleNano/micro scaleLarge scaleCrystallinity Chemical binding structure and layer thicknessContact mechanicsFracture mechanicsBond mechanism 1.1. Interfaces for Cutting-Edge Applications78p ”Systems in Materials” packagingp Integration regardless of materials and fabrication scalesp Seamless bonding: Use of intrinsic surface propertiesIndustrially simple hybrid bonding schemeElectronics Packaging: nm – um, deepknowledge on surfaces/interfaces, specialfabrication atmosphere acceptableAutomotive IoT: Seamless signal transmission via structural materials1.1. Interfaces for Cutting-Edge Applications89p Non-vacuum & low-temp（around <150℃）for diverse materialsp High-reliability such as anti-hydrolytic interfacep Easy solid-state debondingPackagingAdvancedpackagingBEOLFEOLDevice layersBeing borderless Wafers / interposers• Shigetou et al., Proc. 51st ECTC (2001)• Shigetou et al., Trans. Adv. Pckg. (2007) etc.AMD Hotchips 2021 Sr. Fellow R. Swaminathan1.2. Essential Surface/Interface CharacteristicsInsulator 1Interconnections Ultrathin bridge layerInsulator 2 Heterogeneous integration by bonding← Done← Almost done← Not yet910Example of structural materials officially used in automotive companies.Those in red letters are also utilized in electronic substrates and packaging.n Covalent/coordinate bond regardless of the combinationn Chemically stable organic materials: Highly marketable in molding processHybrid interface must be seamless to:p Fabrication scalep Material propertiesGreen technology（eco-logy）Simple & low-cost（eco-nomy）1.2. Essential Surface/Interface Characteristics10112. Lineage to Low-Temp, Non-Vacuum,Reliable Hybrid Bonding1112Bonding by attractive force btwnatomically clean surfaces︓p Covalent/metal bond onlySurface Activated Bonding (SAB) at RT︓Use of dangling bondsChange in chemical/physical surface conditions induced by beam irradiation1) Minimum surface activation condition2) Acceptable increase in surface roughness to ensure full contact 1) + 2) = “clean & flat” surface3) Acceptable adsorption from the environment to maintain bondability3) = Q-time 2.1. Direct Bonding Using High Vac (1990s)1213 !!"<!"# "##!$%$%"!&& !!"=!!"!#!!+!!" ##!#!∗"∗  ⁄$ % #$ ≤ &∗For CMP-Cu film︓Ra 2nmOptimum process window for this CMP-Cu film:Etching depth of 8 – 15 nm + vacuum exposure of less than 0.2 Pa*s.ビーム衝撃によるエッチング深さとCMP-Cu表⾯の化学的組成変化の関係Around 8nm for a clean surfaceorConcept of Hertzʼs contact theoryAdequate etching depth: 8~15 nmChange in mean surface roughness  correspondence to the etching depth.Inactivation @ 0.2 Pa・sRelationship btwn the bonded area and the exposure amount to oxygen2.1. Direct Bonding Using High Vac (1990s)1314Worldʼs first Cu-Cu bonding at RTA. Shigetou et al., J. Surface Sci. 2001 などSiO2 cannot be bonded by SAB method・・・︖Fe contamination from ion gun barrel worked as adhesive layer!Idea of ultrathin bridge layer2.1. Direct Bonding Using High Vac (1990s)1415Cu-Cu Modified diffusion bonding supported by SAB︓Cu-Cu bonding @ 150C via controlled thickness of native oxideAdhesive layer in non-vac atmosphere = Tunable design of bridge structure p High vac needs high cost → Working temp going high → All RT process really needed? → 100℃ higher than RT = 2 degrees up in diffusion coefficient! p Tuning of surface inert layer (ex. native oxide) is necessary: Thinner than volume diffusion distance of Cu ions!Shigetou et al., Appl. Phys. Exp. 2009.2.2. Half Non-Vac Process (early 2000s)15163. Less matrix damage1. Non-vac atmosphere = Adhesion layer on the surface2. Process tep lower than Tg = Less deformation & reactionPhysisorbed/organic contaminantKey of surface modification is on inorganic sideEx. Metal surface Native oxide/chemisorbed layerCovalent or ionic bond: High binding energy that cannot be dissociated with UV light onlyFunctional groupBinding energy Wavelength (nm)16Developing bridging function in the adsorbed molecular layer in non-vac atmospherep Tunable chemical structurep Tunable thicknessp Materials compatibilityp High bond strengthp High interfacial reliabilityMaterial 1Surface layer 1Surface layer 2Maetrial 2Ultrathin bridge layerUse of light2.3. VUV-Based Non-Vac Process (around 2007~)1617Cu e1Cu e2SiO2 e1SiO2 e2Change in valence band spectra of SrTiO3 concomitantly with increasing water adsorption M. A. Henderson, Surf. Sci. Rep. 46 (2002) Change in the ground state of Cu and SiO2 at different humidity conditions  Less than 10 molecular layerse1e2More than 10 molecular layersClean surface in high vacuum ① ②① Lone pair of oxygen to cation sites ② Proton conduction on anion sitesOHHOHH①②Predictable adsorption behaviorWater vapor as the source of bridge layer2.3. VUV-Based Non-Vac Process (around 2007~)1718Water Vapor-assisted ultraviolet (V-VUV) method︓Highly modified hydrophilic bondingp In N2 atmosphere,  <150℃p Bridge thickness ~10nmp “Exposure (s・kg/m3)”as the process parameterp Contact @ RT → Heating @150℃p No bonding pressure is required in theoreticallyp Different interfacial functions by different solvents100 – 200 C around• T. H. W. Yang, C. R. Kao, A. Shigetou, Langmuir Vol. 33 No. 34, 2017 etc.• JP Patent No. 6251935 etc.VUV・OH・HCovalentelectronLone pairOutline of V-VUV method in case of WATER vapor2.3. VUV-Based Non-Vac Process (around 2007~)181919CFRP – Steel, and PEEK - Ti64 bonding @ 150 –200 C, including less thermal strain at the interfaces.Cu-Cu Bumpless Interconnect for Hybrid Bonding. Cu-Cu, Cu-SiO2, Cu-PI interfaces on the same plane @ 150 C.Electronic PackagingPEEK – Pt   bonding for artificial bone partsJ. Elctr. Mtr. (2012), IEEE NANO (2012), Microelctr. Rel. (2016), Mtr. Sci. Eng. C. (2017) etc.Structural MaterialsBio/Medica/Optical materialsPDMS – PDMS interface with  transparency loss < 2%2.3. VUV-Based Non-Vac Process (around 2007~)Newspaper article: The Daily Industrial (2012/10/25)19Irreviersible hydrolysis reaction at V-VUV interfaces︓Irreversible M-O-C（single oxygen bridge）hydrolysis at V-VUV bonding interfaces:• Water penetration to interface• Broken M-O- quickly forms chemically stable oxide • Crack initiation due to stress concentration on unbonded oxide sites 20New tasks for water V-VUV method:p Hydrolysis degradation︓In particular @ inorganic – organic interfacesp Different lifetime for different materials（will talk later）n Target materials: Cu, Al, Ti (Ti-6Al-4V), PEEK, PI, Si，SiC(N), GaN etc.n Water adsorption is hard to be avoided in actual IoT modulesSo, letʻs make the hydrolysis reaction equiriblium!2.4 New VUV-Based Process (around 2010~)2021Alkyl chains with hydroxyls at the and and muti-dentate carboxylates at the bottom (inorganic side)Schematics of anti-hydrolysis bridge layern Hydrophobicity can be tuned via alkyl chain lengthn Alkyl chain keeps connected to the other material“One side is re-bonded while another one is disconnected”2.4. New VUV-Based Process (around 2010~)2122Alcohol - assisted VUV (E or IPA-VUV) method︓As low-toxic source of CH radicalp Use of atomized ethanol, IPA, etc.p Same process as water V-VUV: Exposure (s・kg/m3) as process parameterp Batch process to water cleaning available in near future Outline of Ethanol-VUV surface modification / bonding  method．• Nature Scientific Reports 9 (2019)• Materials & Design 195 (2020)• JPN Patent No. 7018223• CHN Patent No. IIC202391• JPN Patent Application No. 2022-90266etc.p Pseud hydrophobic surfacep Q-time longer than 24hrs for Si-relating materials2.4. New VUV-Based Process (around 2010~)※ Example of Al – polyimide bonding2223Major experimental procedures:1. Ultrasonic washing: Acetone (only for Al) → ethanol → ultrapure water 1min each2. VUV irradiation at different amounts of exposure (s・kg/m3)3. X-ray photoelectron microscopy (XPS) for overall check of surface chemicalbinding status: 2x10-7Pa，Mg-Kα，450W，detection at 15°，φ0.8mm4. Fourier-transform IR spectroscopy (FT-IR) for precise analysis on carbonbinding condition: After E-VUV, transferred to FT-IR equipment in air5. Bonding: contact @RT, 0.04MPa, heating @ 150℃ for 10min6. Transmission electron microscopy (TEM) & electron energy loss spctr. (EELS)Si waferEB depo Al thin film on Si(10 mm × 10 mm × 140 nm)Polyimide (PI)(15 mm × 15 mm × 25 um)Cut intoPolyimide (Kapton) thin film(LEFT) Schematic representation of E-VUV bonding apparatus including XPS/AES.  E-VUV chamber equips ultrasonic atomizer and humidity/pressure sensors.  (RIGHT) Outline of test vehicles.2.4. New VUV-Based Process (around 2010~)2324Less matrix damage: ~2nm deep area is reorganized by V-VUV Both has “bondability”Typical structure of polyimideConventional beam  process in high vac VUV irradiationn fragmentation︓C-O-C，C=O，C-Nn C concentration derives damages on dielectricityn Low damage on matorixO-C O=C BenzeneYang, Kao, Shigetou, Langmuir 2017Before irradiationAr-FAB bombardment in high vacXPS valence spectrum of polyimide before beam irradiationBenzene2.4. New VUV-Based Process (around 2010~)2425Al O1s spectra before/after E-VUV treatment.  Black line indicates before irradiation, colored lines are for different exposure conditions.(a) Spectra normalized with the highest intensity to highlight the difference in chemical binding conditions．FWHN increment due to –OH creation is seen．(b)-(d) Results of curve fitting of spectra after E-VUV treatments.  -OH and C-OOH peaks became apparent. The layer thickness x can be calculated using the peak area obtained by the angle-resolved observations︓'& = '' ) *( ⁄) *! +,- ./Im ︓ Peak intensity of the targeted chemicalcomponent obtained at the detection angle θ1Iu︓Peak area obtained at different angleλm︓Inelastic mean free path of the targetedbridge layer materialSpectroscopy such as XPS is effective to identify the chemical species and atomic concentration, but not suitable to identify the chemical structurep Al O1s specgra︓-OH，C-OOH groups2.4. New VUV-Based Process (around 2010~)2526E-VUVなし218 s・kg/m3794 s・kg/m3Bidentate Al carboxylate formationATR-FTIR results showing thechange in binding structure of C onAl surface after E-VUV treatmentat different exposure conditions.Peaks at 1500 – 1700 cm-1represents the formation ofcarboxylate.Growth of alkyl chainΔ = nasー d = 151 cm-1→ BidentateC. Ohe, J. Phys. Chem. B103, 1999.2.4. New VUV-Based Process (around 2010~)2627Al（on native oxide）PolyimideSaturation: 2000 s・kg/m3VUV-dissolved sites are occupiedHydroxyls are oxidizedRatioofC-C&C-Hbonds(%)Exposure (kg・s/m3)Ratio of C-C to C-H, meaning alkyl formation ratio, on PI surface with parameter of Exposure. Calculated  from XPS C1s curve-fitted spectra.Layer growth linearly follows Exposure until all the reaction sites are occupied.Saturation exposure︓320-470 kg×s/m32.4. New VUV-Based Process (around 2010~)2728No crack after storage testing at 85%RH・85℃ for more than 3 monthsTEM images of the bond interfaces btwn Al and PI．Exposure amount of ethanol-VUV was Al 1890 s・kg/m3，PI 400 s・kg/m3．(Left) As-bonded interface，（Middle）diffraction spots at Point a & b, showing that the bridge layer is amorphous． (右) interface after 3 months of storage testing.p As-bonded sample: Close adhesion via 10-nm-thick bridge layerp After storage testing: precipitation layer from Al side for 20nm width2.4. New VUV-Based Process (around 2010~)28293. For ”Cradle to Grave" Tech: Bondability and Debondability※ Contents from JIEP/IEEE EPS/CPMT ICEP 2024 & 2025※ From here Cu-Cu interface PackagingAdvancedpackagingBEOLFEOLDevice layersBeing borderless Wafers / interposers2930p Automatic nucleation of oxide nanocrystals of inorganic materialsp Limited thickness growth of bridge layerPossible source of Al(OH)3︓③ The excess of Al ions produced by the reduction of the top surface of the natural oxide film by protons reacts with water molecules generated by dehydration condensation of bridge layer endsTEM image of Al – polyimide interface bonded by the ethanol-VUV process.  The interface was kept in 85℃・85%RH condition for more than 3 months. T. Yang et a., Trans. JIEP 20193.1. Trigger of ”Solid-State Debonding”3031A clear "trigger” for solid-state debonding at low temperature that does not overlap with actual operating or reliability test conditions.p Trigger condition must be reached with existing industrial equipment.Bonding technology that incorporates debondindabilityConcept of temperature-based solid-state debonding trigger.Sharp expansion only at the trigger temperature, showing the same thermal properties as common materials in an operation environment.Trigger: Set to about -100°C (can be reached in a common industrial freezer)Expansion ShrinkageReliability test temp.Working temp.Thermal expansion ∝ stressRTNéeltemp., TNTemp. highTemp. lowBridge layerCommon materialsNegative CTE mtr.Conventional separation triggers(melting, burning etc.)Difficult to set the trigger at higher temp for high heat-resistant mtrs3.1. Trigger of ”Solid-State Debonding”3132Use of antiferromagnetic nanocrystals: p Steep expansion at about -100°C: Due to spin-lattice interaction below Néel tempp Especially for CuO: Volume strain of around 0.003 in Δ 20 C across the triggerUse of the low-temperature expansion properties of some antiferromagnetic nanocrystals3) Spin-lattice interaction: Lattice expansion for  relaxation of geometrical frustration2) Spin orientation cannot be determined geometrically1) Fixing spin orientationA nanocrystal with triangular spin configurationsTaken from: Kitani et al., Thermal Measurement 44 (2017)Mtr. 2 (Cu )Mtr. 1Bridge layerBridgeComposed of Cu-related compound10nm aroundNucleation of CuOnanoparticles After bondingCooling to below TNStressExpansion of bridge layerSolid-state debonding3.1. Trigger of ”Solid-State Debonding”銅－銅積層体の分離⽅法及び銅－銅積層体，特許番号︓07597418 登録⽇︓2024-12-02PCT/JP2022/027099 (EP, CN) , JP2021-11552732Mtr. 1Mtr. 2 (Cu)Bridge layer33Test coupon︓Oxyten-free Cu platel To investigate the evolution of chemical binding status only on Cul Highest purity (>99.96%) of Cu commercially availablel Used in various applications: lead frames, heat sinks, plating source, etc.円柱形原料をスライス スライス⾯Small cut-off to ensure physical contactAround 1.5 mm直径10mmSchematic representation of Cu test coupon: Mean roughness (Ra) 10nm aroundAnti-hydrolytic bridge layer:1) Dehydration condensation at the end of the bridge2) Dynamic competition of hydrolysisConcept of IPA-VUV bridge layerCuO nanocrystals:Steep expansion at the temperature below TN (around -100 C)Slicing into platesΦ 10mmSliced surface Mirror polishing︓SiC paper #4000 + diamond splay 3µmΦ3.2. Process Design3334Chemical structure indicating bridge formation on Cu1) hydroxide（due to ・OH）︓Cu – O – H2) Cu carboxylate at the bottom  ︓Cu – O – R – C – OH ‖OH Checked with Cu2p3 spectraChecked with C1s spectraNative oxide Cu(2-x)O0.9eV︓Cu-O-1.8eV︓Cu-OHCu-O-Cu-OHCu-O-Cu-OHSince the presence of native oxide is largest, the energy gaps from the native oxide peak were used to the curve fitting.Cu2p3 spectra taken at 30° in different Exposure conditionsNormalized intensity to the maximum intensity in order to highlight the difference in binding conditionsExample of angle-resolved spectra at E=6.028. Taken at 15 and 30°.Checked with Cu2p3 spectraVUV only in vac (native oxide)VUV only in vac3.2. Process Design34Chemical structure indicating bridge formation on Cu1) hydroxide（due to ・OH）︓Cu – O – H2) Cu carboxylate at the bottom  ︓Cu – O – R – C – OH ‖OH Checked with Cu2p3 spectraChecked with Cu2p3 spectra35C-C as standard2.1eV︓C-O-(H)4.3eV︓C=O C-O-(H)C=OC=OC-O-(H)Checked with C1s spectraSince the presence of C-C is considered dominant, the energy gaps from C-C peak were used to the curve fitting.VUV only in vac (native oxide)VUV only in vacC1s spectra taken at 30° in different Exposure conditionsNormalized intensity to the maximum intensity in order to highlight the difference in binding conditionsExample of angle-resolved spectra at E=6.028. Taken at 15 and 30°.3.2. Process Design35← Bridge growth reaches max36Evolution in bridge layer thickness according to Exposure︓p Layer growth has a saturation point︓About 2.4 s・kg/m3p Follows Freundlichʼs isotherm equation︓Isotherm reaction between the solid-state surface and gas molecules occurring only at the surface of the bridge layerRelationship between Exposure and the calculated bridgelayer thickness obtained from the curve fitting results ofangle-resolved spectra.! = #・$!・"01Correlation coefficient R > 0.96 Freundlichʼs isotherm equation︓l a, b, c: arbitral coefficientl X: Exposure, Y: Calculated bridge thicknessl Fitted to different isotherm equations ． 1)Langmuir (saturation at monolayer formation)，2) Michaelis–Menten equation (layer growthincluding chemical reaction inside) ， 3)Freundlich equation (successiveadsorption, only at the top of the layer）• Approximate curve wasforced to go 0 when E is0, assuming that nobeidge formation at E=0.• Maximum point wasevaluated from differentelement peaks.3.2. Process Design3637Bridge structure on Cu surface︓p Cu carboxylate at the bottom︓Bidentate coordinationp Maximum thickness︓Arounf 2.5nm (may be a little thicker in normal air)w(CH2)n(COO)δ(CH2) or n(C=O)Peaks of bands showing coordination structureATR-FTIR spectra of oxygen-free copper surface treated with IPA-VUV E=6.028 s・kg/m -3. Since the measurementswere performed in air, the sample surface was exposed to air after the IPA-VUV treatment. Although the spectrum isnoisy due to the small thickness of the bridge layer, a group of peaks of bands originating from the bidentate structurewere observed. Ref︓Fausto et al., J. Molecular Structure 349 (1995) 439.Schematic structure of Cu carboxylate derived from the results of XPS angle-resolved measurement and ATR-FTIR observation. 0.3 nm 1.4 nm 0.8 nm3.2. Process Design3738p Shear strength of oxygen-free copper specimens bonded at Exposure near 2.4 s  kg/m-3 : >20 MPa, cohesive fracturep Since the overall shear strength is obtained by dividing the shear strength by the nominal bonded area, the true shear strength can be largerp No strength degradation after 85%RH・85℃ storage testing for 1000 hoursBonded bodyShear tooladhesive Sample stagePush one side of the samplesScanning electron microscope (SEM) images of fracture surfaces aftershear test of oxygen-free copper bonded under conditions near themaximum bridge formation condition. (Left) low magnification, (Right)high magnification. In the high-magnification image, cohesive fracturebetween surfaces is observed.Schematic diagram of theshear test apparatus used inthis study. The maximumshear load was 500 N. If thebond strength at the interfacewas larger and did notfracture, the load was appliedrepeatedly.3.3. Bondability & Debondability3839p Test sample: Kept at -60℃ for 24 hours (before the trigger temp)p Transmission electron microscopy (TEM) observation: The bonded samples are thinned using a focused ion beam (FIB). The final thickness is about 80 nm, and the sample is exposed to air for about 72 hours before observation.p There are some areas that appear to be contact defects caused by surface unevenness, but these areas are not cavities and are filled with bridge component.TEM low magnification image of the bond interface between oxygen-free Cu plates.Damage during FIB thinningTEM observation area3.3. Bondability & Debondability3940Point 3Point 2（insufficient bonding region）Point 1Point 1 Point 2Point 3CuCuCuCuCuCuBridge layerBridge layerCuO nanoparticlesCuO nanoparticlesCuO nanoparticlesNucleation of CuO nanoparticles was confirmedTEM mid-magnification images3.3. Bondability & Debondability40414 FIB points100 umCu CuUniform debonding was found in all FIB positionsp Kept at -95℃ for 24 hours (the trigger temp)p FIB observation at 4 different positions on the interface3.3. Bondability & Debondability4142Muti-functional interfaces will be a key to next generationʼs device integration.  To achieve it via industrially simple way, V-VUV method is developed:1. Seamless interconnection btwn BEOL & Adv. Pckg. is necessary2. Low process temperature & non-vacuum is important3. E-, IPA – VUV methods realized waterproof bondability4. Debonding of Cu-Cu interface was feasible at around -100C5. Calculation for structural change is highly necessary nowSummaryThe research works in this presentation was/is supported by 1) Innovative Science and Technology Initiative for Security, 2) Scientific Research funding, and 3) LSTC.  We thank for those successive supports.42