Engineering a Tunable Cu-Selective Oxide-Suppressing Coating to Enable Reliable Cu-to-Cu Direct Bonding for Advanced Interconnects

The continuous scaling of semiconductor devices, driven by Moore’s Law, demands advancements in interconnect technologies. Cu-to-Cu direct bonding has emerged as a critical solution for enabling ultra-fine pitch, high-density interconnections with superior electrical and thermal performance compared to traditional Cu-to-solder joints. This bonding method is pivotal for applications such as 3D integration, FOWLP, and 2.5D/3D packaging, supporting miniaturization, high-speed data transfer, and improved thermal management. However, Cu oxidation during processing presents a major barrier, degrading bond integrity, increasing interfacial resistance, and complicating backend-of-line (BEOL) packaging integration. To address these challenges, we developed an ultra-thin (2–5 nm) Cu-selective oxide suppression coating using standard industry-compatible techniques such as chemical vapor deposition (CVD) and liquid-phase deposition (LPD). The coating effectively prevents Cu oxidation during high-temperature thermal compression bonding (TCB) without requiring high-vacuum equipment or costly metal coatings, enabling scalability for heterogeneous packaging. RAIRS-QCM metrology validated the coating’s chemical stability and persistent oxidation resistance even after two months of ambient storage. RAIRS analysis confirmed ~52% oxidation suppression after 1-hour annealing at 300°C in air. Bonding tests on 5 nm passivated Cu at 300°C, 40 MPa for 1 hour showed strong Cu–Cu bonds with a shear strength of 40.7 ± 4.2 KgF, exceeding MIL-standard. STEM-EDX confirmed a defect-free interface and effective oxidation suppression without hindering bonding. This work establishes the developed coating has strong potential as a scalable, high-throughput solution to enhance Cu-to-Cu bonding reliability, enabling next-generation semiconductor packaging with improved electrical, mechanical, and thermal performance.

Due to an increasing demand for high performance electronics, e.g. mobile, wearable, artificial intelligence for self-driving, heterogeneous 3D integration chips are highly desired since the integration scheme can be significantly outperforming a 2D integration chip. There are several 3D stacking integration methods to connect different components, such as wafer to wafer (W2W) bonding and die to wafer (D2W) bonding. W2W hybrid bonding offers a massive connection in a bonding, which decrease the processing cost in particular for small chips. However, there is a limitation that the die must be equal size for the pair wafer. Furthermore, no Known Good Die (KGD) selection is possible in W2W bonding, which can give a negative impact on stacking yield. On the other hand, D2W is able to handle different die sizes, which allow great flexibility in 3D integration. In addition, the capability to select the KGD ensures the yield. The most commonly used interconnection technique for D2W is solder base thermal compression bonding (TCB). However, there are several challenges in the stacking to achieve below 10 μm pitch. In addition, there is a certain limitation for scaling down below 5 μm of the bump pitches. In order to overcome the issue, implementation of hybrid Cu-Cu bonding technology is desired. In this presentation, the alternative scheme for solder base thermal compression bonding will be introduced, which enables us to achieve below 10 μm pitch by TCB. In particular, the challenge and solution regarding electrodeposition will be discussed. In addition, our integration approach for hybrid Cu-Cu D2W bonding will also be introduced.

The continued scaling of transistor geometries for semiconductor devices has been placing an increased demand on the next-level interconnect technologies. Heterogeneous integration of memory and logic devices is increasingly becoming the norm for next generation mobile, high performance graphics, and network applications. This requires advanced packaging technologies with capabilities for very high signal routing densities, efficient power distribution, and superior signal integrity. In addition, 3D package integration is often required, especially for mobile applications. This places an increased emphasis on the package technology’s z-height reduction and thermal performance capabilities. Traditional organic laminate substrates that apply flip chip bonding have met the semiconductor industry’s advanced interconnection needs for over 15 years [1]. With the continued advancements in materials and processes, laminate substrates are expected to satisfy the majority of advanced package performance and cost requirements for years to come. However, the feature size limitations and the electrical and thermal performance constraints will continue to restrict laminate substrates from meeting the integration requirements for next generation mobile, high performance graphics, and networking applications. Emerging silicon-based interconnection technologies, such as through silicon via (TSV) have shown promise in this area. By leveraging the back end of line (BEOL) damascene processes of the wafer fab, multi-layer sub-micron signal trace densities can be achieved. However, the supply chain limitations and intrinsic cost implications have limited the proliferation of 3D IC technology. In particular, for silicon interposers, there can be an undesirable effect to z-height and electrical performance due to the inherent thickness and parasitics of the silicon interposer. This paper introduces an innovative high density fan-out (HD-FO) semiconductor packaging technology that bridges the gap between organic laminate-based substrates and inorganic foundry-based silicon interconnection technologies. Silicon Wafer Integrated Fan-out Technology (SWIFT™), also called chip last HD-FO, incorporates the fine feature size capabilities of wafer-level packaging (WLP) coupled with the advanced flip chip packaging technologies, such as chip on wafer (CoW) and Package-on-Package (PoP). The result is a highly integrated structure that has exceptional electrical, mechanical, and thermal performance benefits – compared to incumbent packaging technologies – to meet the needs of next generation mobile, high performance graphics, and network applications.

Current DRAM advanced chip stack packages such as the high bandwidth memory (HBM) use throughsilicon-via (TSV) and thermal compression bonding (TCB) of solder capped micro bumps for the inter-layer connection. The bonding process has low throughput and cannot overcome the challenge of scaling below 40 μm pitch. These are compelling reasons to seek an alternative approach such as hybrid bonding. The pursuit of fine pitch die stacking with TSV interconnect using hybrid bonding is pervasive in the packaging industry today due to the promise of improved performance. Specifically, the Cu interconnect provides improved thermal and electrical performance and the all inorganic interface of the complete die stack offers enhanced thermal-mechanical performance and reliability in the final chip stack. Direct Bond Interconnect technology, also known as low temperature hybrid bonding, forms a spontaneous dielectric-to-dielectric bond at room temperature and then establishes metal-to-metal connection (usually Cu-to-Cu bond) by a low temperature batch annealing process (150 - 300°C). The direct bond process eliminates the need for solder and underfill and associated problems. While the hybrid bonding exists today in wafer-towafer (W2W) format in high volume manufacturing, chip to wafer (C2W) bonding developed for future product lines is making significant process in the past three years. A bonding process with high throughput has been demonstrated with electrical test yield above 90% with a daisy chain structure that covers 50mm^2 of bonding area. The bonded parts showed superior reliability performance in temperature cycling, high temperature storage and autoclave testing. This paper presents the latest development in C2W hybrid bonding and demonstrates the low temperature annealing capability and integration with TSV

High density interconnection is a key technology to realize the miniaturization trend in Integrated Circuit (IC) industry, and to reduce power consumption for next generation mobile devices. In advanced three-dimensional (3D) package, fine pitch pillar bump is deployed not only to fulfill ever-growing I/O density requirement, but also provides better electrical performance than that of traditionally solder bump [1]. Meanwhile, to maximize die area utilization, die sizes of top and bottom die are generally kept as close as possible, leaving stringent spacing for underfilling, and makes fillet width control and dispense space two great challenges for capillary underfill (CUF). In this paper, test vehicle of fine pitch micro-bump interconnection was achieved by thermal compression bonding (TCB) with Non-Conductive Paste (NCP). This paper addresses development of TCB process with NCP material by different TCB condition and NCP properties to show the correlation between TCB process parameter and NCP material. In order to achieve spherical bump shape, NCP gel time was studied in different bump melting time. Fillet width was studied to control the exceeding area around chip. Void was also studied for TCB parameter adjusting. Finally, reliability test was tested for NCP properties discussion.

Conventional flip chip technologies such as the mass reflow (MR) process and the thermal compression bonding (TCB) process are commonly used technologies in the micro assembly field. However, there is a continuous need for next generation interconnection technology to achieve a low form factor with increasing die and substrate complexities. Moreover, very thin 3D integrated packages and 2.5D packages with thin interposer die promise advanced interconnection technologies for mobile and wearable applications. With this point of view, the most important factor in interconnection is optimal thermal energy control for soldering. However, a conventional MR process cannot provide any selectivity and controlled thermal energy transferring with the traditional convection reflow. Its high thermal budget makes warpage an issue, aside from other side effects. To overcome the MR process problems, recent researches and industries have focused on developing a TCB process with non-conductive paste (NCP) or non-conductive film (NCF) due to TCB's unique advantages of low mechanical and thermal stress. However, the productivity of the TCB process is not comparably to the conventional process. Laser-assisted bonding (LAB) with beam homogenizer is considered to be the next generation interconnection technology due to its excellent thermal selectivity, extremely fast ramping up speed with purely controlled wavelength. This LAB process offers a very stable interconnection quality as well as robust functional and reliability result. Interestingly, it also achieves excellent results with thin coreless substrate due to its selective heating area availability. This paper will discuss the laser heating mechanism, multi-chip & component bonding availability and advantage of LAB from an assembly industrial perspective.

It is crucial for Cu TSV to be reliable at the back-end-of-line (BEOL) procedure particularly at high temperature process step. Any unreliable Cu TSV may cause residual from thermal stress due to the mismatch of the coefficient of thermal expansion. Therefore, it is important to investigate on the behavior of Cu pumping whether it will affect the electrical performance in BEOL integration. Two sets of Cu pumping with pitch 30 µm and 40 µm were annealed to measure their resistance at the temperature lower than 250°C. Based on the results, the narrow pitch of 30µm can be applied in post via last process below 250°C for BEOL procedure in 3D integration.

Recently, Flip Chip Packages provide the ideal solution for low to high I/O, high electrical performance demand in handheld devices where high frequency, high speed are required. To approach these requirements, we present an alternative fine bump pitch solution of low cost and high throughput which used thermal compression bonding (TCB) combining with molding underfill (MUF) technology and comparing with traditional mass reflow (MR). As we known MR is the lowest cost and mature process in general. By using coreless substrate with embedded fine-trace substrate (ETS) technology to achieve package miniaturization requirement. Comparing with conventional substrate, coreless substrate technology eliminates the substrate core, and utilize build-up layers to interconnect the chip and the PCB board. It brings about not only low Z-height, lightweight, but also short interconnection distance and good power integrity. The ETS coreless technology is a promising solution for the next generation substrate. A Flip Chip Scale Package (FCCSP) and ETS coreless substrate combination are used to this paper experiment. The major challenge is thinner ETS coreless substrate to induce warpage concern which because of no core material as supporting material, also ETS coreless substrate no rigid product characteristic and easy to bring handling issue during manufacturing and assembly process. Thermal compression bonding could offer less thermal budget and stress to mitigate CTE mismatch between silicon chip and coreless substrate. The study result of warpage control between TCB and mass reflow process, the TCB could be provided less warpage behavior after compared to traditional mass reflow, also this TCB technology is popular used for thin core, coreless and advance silicon node product field. The characterization analysis will utilize simulation methodology & typical reliability testing (Temperature Cycle Test, un-bias HAST and High Temperature Storage Test) results as a verification monitor items for TCB process with ETS coreless structure feasibility evaluation. Finally, this paper will find out the suitable key process index for future product application.

3D integration is worldwide considered as one of the most important key technology for microelectronics to meet the growing demands regarding more functionality with concurrent increase in performance as well as miniaturization and cost reduction. So 3D integration is of main relevance for application areas e.g. cyber physical systems, internet of things, ambient assisted living (AAL) as well as information & communication, logistics, security, automotive, health care and industrial electronics. Besides following “More Moore”, Europe is pursuing a strategy on heterogeneous integration approaches following “More than Moore”. In this context, individual and different 3D integration approaches are adapted to the specific application scenarios.Interposers with Through Silicon Vias (TSV) are becoming a very important element for the realization of 3D System in Packages (SiPs). Main advantages of silicon interposers are the decoupling of front end/back end processing for the implementation of TSVs, redistribution layers (RDL) and the integration of active and passive devices. Besides independent manufacturing, interposers can be realized in short time-to-market time frame and in a cost effective way. TSV interposers are designed and manufactured for the different application areas which results also in different technical specifications ranging from high density TSV integration and high density RDL for digital applications to interposers for RF application as well as MEMS integration and optical interconnects.The presentation will highlight results and technical achievements for 3D integration using TSV interposer and addresses as well the broad spectrum of topics from design, technology and reliability related to 3D systems.Concerning technical features, interposers deal with high density wiring redistribution layers (RDL), TSVs and top/bottom side interconnect formation (bumping). This allows the electrical signal routing across the top side and to the interposer back side. Some new applications appear to require up to 4 layers RDL of less than 1μm line/space and silicon oxide/nitride dielectric layer.Silicon interposers with TSVs provide additional features to address 3D-SiP for heterogeneous integration. These include:Device carrier for stacked devices,High density wiring between (stacked) components,3D device stacking using TSVs,Integrated passive devicesEmbedding of active devices into the IP,Functional layer integration (actors, sensors, antennas),Modularization,Integrated test features For the assembly and 3D stack formation of the devices, different interconnection technologies, e.g. micro solder bumps (SnAg) and copper pillars, are used to deal especially with surface topography of the devices and warpage of the board/substrate.Beside silicon interposer, also glass interposers are emerging elements for specific applications. Compared to silicon interposers, glass interposer currently have only limited via dimension and cannot deal with high density TSVs, e.g. <5µm diameter and 10µm pitch. For this, the supply chain is still emerging. The metallization process for silicon interposers is commonly established in wafer fabs. However, most of these facilities do not possess via-last or bumping capability. SUMMARY 3D integration technology is one of the main drivers in packaging and system integration to meet the requirements for high functionality, highly miniaturized smart systems.Future advanced 3D systems will result in complex 3D stacking approaches using the TSV technology. Silicon interposers with TSVs are an important element to combine different advanced devices into one miniaturized system (SiP) with high functionality and to overcome currently existing issues regarding TSV integration into active devices. One important task is the supply chain between e.g. IDMs, OSAT or packing houses.Another crucial aspect is the balance between performance improvement and 3D manufacturing cost (TSV & packaging). So the implementation of 3D integration using TSV and interposer is very product specific. 3D integration requires, beside the technology approaches, also an overall SiP process integration approach which addresses design, technology and reliability.Fraunhofer IZM’s center “All Silicon System Integration Dresden - ASSID” and the Fraunhofer Cluster 3D Integration (http://www.3d-integration.fraunhofer.de/en.html) are focusing on the development and prototyping of 3D systems using Cu-TSVs in active devices (via middle, via last) and silicon interposers as well.

Along with the rapid spread of portable electronic products on the mobile computing market, the increase in the use of video streaming, photo sharing and also other data-intensive applications keep growing up continuously for now. More and more IoT/Wearable and 5G connectivity devices are required with Radio Frequency (RF) and Front-End Module (FEM) which has driven the development of IC packaging towards on small form factor, thin profile, better electrical and thermal performance, as well as 3D stacking for multi-function integration [1]. To approach these requirements, the System in Package (SiP) can be a combination of one or more chips plus optionally passive components by using Surface Mount Technology (SMT) and 3D structure of double side into a single package to offer a small form factor, high performance and systemization implemented. The high speed SMT process accomplishes the high-density with more than 50 discrete passive as well as active components and heterogeneous integration on package level approach. The development of double side technology offers the advantage of package size shrinkage by the same integrating discrete passive and active components layout. In this paper, the innovative packaging solutions of 3D double side SiP including the platform for both strip form of substrate base and wafer form of Fan-Out Redistribution Layer (RDL) base will be well introduced. Fan-Out RDL is an extension approach of Wafer Level Chip Scale Package (WLCSP), this technology is different from conventional wire bond or flip chip packages because the redistribution dielectrics and fine-line plated conductors are used for interconnection to replace the packaging substrates. As a case study, the calculation of 3D SiP package size can be shrunk around 50% area and the total package thickness can achieve around 15% z-height reduction with thin form coreless substrate and Fan-Out RDL technology utilization. The characterization analysis will apply simulation methodology for electrical comparison on DC resistance and parasitic inductance, thermal comparison on Theta JA (°C/W) and warpage comparison on the package structure of 3D double side SiP. Also, the typical reliability testing (Temperature Cycle Test, High Temperature Storage Life Test, Unbiased High Accelerated Stress Test) are built to verify 3D double side SiP structure for future IoT/Wearable and 5G devices application. Currently the market trends clearly drive towards 3D double side SiP, so this article illustrates the innovative packaging solutions with both substrate base and Fan-Out RDL base to provide a unique opportunity for enabling 3D integration and system in package.

I.Introduction2D transition metal dichalcogenides (TMDs) exhibit electronic properties from semimetals to wide bandgap semiconductors due to their thickness dependent bandgap. This property opens a wide diversity of applications that can be made from TMDs. For 3D heterogeneous integration of TMDs into the back-end-of-line (BEOL) of Si complementary metal-oxide-semiconductor circuitry, wafer-level direct growth (without film transfer) of TMDs within the BEOL thermal budget limit (550 °C/2 hours or 500 °C/5 hours [1]) is essential. In the literature, the majority of the TMDs (e.g. MoS2) are achieved from high temperature (650 °C - 1100 °C) deposition/anneal processes that are not compatible with BEOL [2]. In this work, MoS2 is successfully grown by chemical vapor deposition (CVD) approximately at/below BEOL thermal budget limit. We explore the potential of the achieved MoS2 films for BEOL logic (i.e. transistors), memory and sensing applications.II. CVD of MoS2 MoS2 was grown by CVD in a commercial 300 mm atomic layer deposition (ALD) reactor fitted with a showerhead. Mo(CO)6 (purity 99.99%, carried by N2) and H2S (purity 99.999%, 1% in Ar) were employed as the precursors. The reactor temperature was restricted at a low temperature range of 350 °C - 550 °C and the chamber pressure was maintained at ∼2.2 Torr. Growth was achieved (confirmed by Raman spectroscopy) on a selection of substrates including: SiO2 (85 nm) on Si (p++), c-plane sapphire, glass, and amorphous alumina (~30 nm by ALD on c-plane sapphire and on glass). It is noted that cm-scale substrates were placed throughout the chamber demonstrating that uniform and continuous film deposition is achievable across a 300 mm diameter with a high level of repeatability.III. Results and DiscussionHigh-resolution cross-sectional transmission electron microscopy (TEM) shows that 2D layered and polycrystalline MoS2 of ~10 nm is formed continuously and uniformly on a SiO2/Si substrate at 550 °C for 2.5 hours. Plan-view TEM also demonstrates the hexagonal structures of the MoS2. A rapid growth rate of ∼6 monolayers/hour on SiO2/Si is remarkable. Growth rate is slightly different depending on the substrates used. A rapid growth time is important in terms of reducing the thermal budget, but this comes at a cost of small grain sizes that are ~5 nm - 20 nm from this work, compared to μm-scale grain size achieved at 550 °C in the CVD of MoS2 by Kang et al., in which 26 hours was needed for 1 monolayer formation [3]. Due to the small grain size, charges are trapped at the high density of grain boundaries restricting lateral charge transport which is detrimental to transistors. This effect is also demonstrated in our work by 4-point resistivity and Hall-effect measurements, which show that the MoS2 films are highly resistive with a very low carrier concentration of 1014 - 1015 cm-3.Furthermore, MoS2 formation is achieved at 450 °C and 350 °C. The reduction in growth temperature from 550 °C, which is at the limit of the maximum temperature of the BEOL thermal budget limit [1], is also a crucial step (apart from reducing growth time) towards achieving 3D heterogeneous integration as this allows room for more manufacturing steps, for example, a dopant incorporation/activation step to functionalize TMDs for transistors.Although MoS2 grain boundaries and stoichiometric defects resulting from the low thermal budget growth are detrimental to lateral charge transport in transistors, these can be leveraged for memory and sensing functions. For memory, vertical transport memristor structures (Au/MoS2/Au) incorporating ~3 nm MoS2 (550 °C, 0.75 hour) show memristive switching and a stable memory window of 105 between the high-low resistive states with a retention time >104 seconds. The switching set and reset voltages are reduced compared to memristors made from single-crystalline MoS2 processed at higher temperatures. For sensing, interdigitated electrode-based gas sensors fabricated on ∼5 nm MoS2 (550 °C, 1.25 hours) show excellent selectivity and sub-ppm sensitivity to NO2 gas, with a notable self-recovery at room temperature without extra energy input.IV. ConclusionsRepeatable, uniform and continuous growth of MoS2 is achieved by CVD approximately at/below BEOL thermal budget limit in a commercial 300 mm reactor. Memristive and gas sensing functionality are achieved from the MoS2 films with an indication of reduced power consumption. This work advances a key enabling technology objective in emerging materials and devices for 3D heterogeneous integration.

Flip Chip Packages are the popular packages in many different applications. Flip Chip can provide the ideal solution for low I/O to high I/O, high electrical performance demand in where high frequency, high speed are required. By using coreless substrate with embedded fine-trace substrate (ETS) technologies to achieve package miniaturization requirement.Comparing with conventional substrate, coreless substrate technologies eliminate the substrate core, and utilize substrate layers to interconnect the chip and the PCB board. It brings benefits not only with low Z-height, lightweight, but also offers short interconnection distance and good signal integrity. The ETS coreless technology is a promising solution for the next generation substrate. To approach these requirements, we would like to discuss the suitable process for laser assisted bonding (LAB), thermal compression bonding (TCB) combining with molding underfill (MUF) technology and comparing with traditional mass reflow (MR). A Flip Chip Package and ETS coreless substrate combination are used for this paper experiment. The major challenge is thinner ETS coreless substrate will induce more warpage concern because of no rigid core material as supporting structure, thus ETS coreless substrate with less stiffness, is easier to bring handling issue during assembly manufacturing process. Thermal compression bonding could offer less stress to reduce CTE mismatch between silicon chip and coreless substrate. The study result of warpage comparison among TCB, LAB and mass reflow process, shows that the TCB could provide less warpage. Furthermore, TCB technology is popular used for thin core, coreless and advance silicon node product field. For LAB, it can provide the better throughput than TCB, and also provide more accuracy fine pitch bonding than MR.

The multi-chip module assembled with a composite layer of thin film on top of organic substrate is presented in this paper. This is a new-arising assembly technology with equivalent electrical performance of 2.5D package but much simplified supply-chain processes. We name this package as 2.1D package which converts the silicon interposer on the substrate. In this paper, the implementation of 2.1D technology on the monolithic, daisy-chain test vehicle is described. We employed thermal compression bonding (TCB) to mount two large dies with minimum 40 ?m-pitch micro bumps onto 45 x 45 mm organic substrate using 2/2 µm line width/space (L/S). Thermally induced misalignment, substrate warpage and the ELK (Extreme Low-K) stress during micro bumps joining with micro pads on substrate were evaluated. The mechanism of micro bump misalignment during solder formation has been experimentally and numerical validated by TCB and conventional mass reflow (MR) process. Finite element analyses were conducted to understand the 2.1D package warpage and stress behaviors, and hence defined better materials and process parameters. Simulation results showed that micro bump joining by TCB has 45% misalignment improvement as compared to MR process. In stress simulation results, the ELK layer stress of micro bump using TCB has a 59% reduction with reference to MR. In addition, the warpage behavior of fine-line organic substrate and 2.1D full package were measured using conventional shadow moire system. Results showed that the warpage variation of thin-film coated substrates was very stable within micro pads area that has less than 10 µm differences under high temperature period (120~260 °C). However, the package moire results showed that the thermally attaching of stiffener ring could significantly affect the global package warpage based on moire contours and warpage distributions. The reliability of this developed 2.1D, multi-chip test vehicle using TCB assembling processes was validated as well. This package passed MSL4 preconditioning and 1000 thermal cycles using G-conditions (-40~125 °C).

Novel and emerging packaging technologies expand the designer's toolbox. Metal coated polymer spheres (MPS) for ball grid array (BGA) assembly is a promising interconnect technology improving reliability, while high thermal conductivity substrates, e.g. AlSiC and AlN, is interesting for enhanced thermal performance. But new tools bring along new challenges in the design phase of innovative packaging solutions. Knowledge of how these tools influence the system characteristics is therefore key; e.g. electrical, mechanical and thermal performance. This study reports on the thermal performance of several novel and more traditional interconnect and substrate technologies. It comprises a relative thermal impact study of individual technologies. The system consists of a power dissipating silicon die assembled onto different substrates with varying interconnect technologies. The study was performed with finite element analysis (FEA) assisted with a compact model and is scheduled for comparison with identical fabricated systems. The results show that it is possible to utilize FEA efficiently on a system scale during the design process with sufficient accuracy. It also reveals that the combination of interconnect and substrate technology should be chosen with care, especially regarding the system's thermal performance, disclosing potential reliability issues and illustrating cost-benefit tradeoffs.

The thermal performances of multichip modules (MCMs) are compared on the basis of their interconnection technologies. The comparisons are made for hermetic and conduction cooled use environments. The thermal performances of the chip-first-type high density interconnect (HDI) technology, the flipped chip (FCP) technology, and the flipped tape automated bond (FTAB) technology are analyzed and compared for the MCM applications. The results show the thermal performance of each interconnect technology and the most effective ways of improving the performance of MCMs.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>