[in Japanese]

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[in Japanese]

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[in Japanese]

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The new type package named “interposerless BGA” has been developed focusing upon ultra thin package, cost-saving and material minimum in Packaging and Testing Engineering Divison, NEC. This package has the characteristic advantage such as ultra thin package and easily handling for design. Because it is possible to form fine pitch pattern due to additive method, moreover electrode drawn out for Electro-plating is unnecessary. We tried making up Face-Up-Type interposerless BGA. As a result, it is expected that this package can be assembled in the high yield. In this presentation we would like to show the evaluation results on a package assembly.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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When defective chips are found in increasingly expensive, high-density PWBs (printed wiring boards), it has become ever more economically important to be able to replace those chips and reuse the boards. This task is made extremely difficult, however, by the difficulty of removing the sealing adhesive that is used between chips and PWBs as protection against dust, moisture, and heat-shock. This study is intended to determine what existing adhesives might be more amenable to removal even after they have been cured and to report the development summary of such products.

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[in Japanese]

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In recent years, mobile computing technology has developed remarkably for increasing demands. Nowadays notebook type personal computers (PC) have become small and smart enough to carry them outdoors for casual uses. As the result, various environment-resist properties are required for notebook PCs and their parts. For example, a dust protected membrane switch (MBSW) for PC’s keyboard is developed for the needs. Recently, further properties, that is, waterproof performance is required for the MBSW. In this paper, our concept for the MBSW and performance of our new MBSW, developed by improving waterproof sealing materials and modifying manufacturing processes are described.

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[in Japanese]

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We improved the high elastic modulus copper clad laminated sheet. These materiales have many characteristics of low bending, low CTE, low moisture resistance, high insulating resistance, high reliability of PTH and laser drilled viahole and high thermal conductivity.

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[in Japanese]

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A high-density semiconductor package needs detailed interconnection for the junction to a semiconductor tip and a package board. Furthermore, it also needs detailed wiring and the connection between layers of the small diameter of a package board. Therefore it is anxious about a fall of mechanical and the electric connection reliability of a connection part. Moreover, junction by the Au stud bump is adopted as FCBGA and MCM (Multi Chip Module) in which FC (Flip Chip) is mounted. By this method, a semiconductor tip is mounted in a package board under high temperature and high pressure. In the conventional package board, elastic modulus of material falls greatly at high temperature. Therefore the pad for bump connection sinks and it may cause poor connection. We developed high reliability semiconductor package board material.

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In recent years, the demand of high speed system and down-sizing for many kind of electronic equipment is increasing. To meet this demand, the frequency of CPU tend to be higher, and I/O number of CPU is increasing. From a viewpoint of Build-up PWBs, high-density wiring is required to packaging substrate, and thickness uniformity is also required to each of build-up layer. In this paper, we report a newly-developed thin film adhesive for Build-up PWBs, consist of thin metallic seed layer, polyimide core film layer, and polyimide-type low dielectric constant adhesive layer. The thin film adhesive can be adopted semi-additive method to fabricate fine-pitched circuit(L/S=10/10 μm), and exhibit high glass transition temperature, low CTE characteristics, and thickness uniformity of dielectric layer.

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A newly developed stress relaxing material for build-up boards using expanded porous polytetrafluoroethylene (Gore-Tex^®) is discussed. This material features low elastic modulus even under a temperature of −60C and great crack resistance benefited from its high elongation. Furthermore, it satisfies the needs of laser process-ability and gap-fill properties required for substrate boards, as well as having superior dielectric properties. By using this material in a build-up board for flip chip type of packages, it is expected that the connection reliability, which is influenced by the difference of CTEs between a semiconductor chip and a substrate board, can be improved.

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We have developed new type of electrodepositable polyimide(ED-PI), which is the composite material of the specific polyimide and other cationic polymer. The new ED-PI shows particularly low elastic modulus and low water absorption. We describe the concept about a structure design and its functional assignment of new ED-PI, and discuss the relationship between physical properties and the microphase-separated structure of the film.

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The multi-styrene groups resin (MuSt) cured at relatively low temperatures (∼180°C) with no curing agents under nitrogen atmosphere. The cured MuSt showed an excellently low dielectric constant (ε@10GHz=2.5) and low dielectric dispersion (tanδ@10GHz=0.0012). Its thermal decomposition temperature was 440°C under nitrogen atmosphere and its glass transition temperature was over 400°C. Polyphenyreneoxide (PPO) was effective as a modifier for the toughening of cured MuSt. When using 30wt% PPO as a modifier for cured MuSt, the tensile strength and the elongation of modified resin were 75MPa and 26%, respectively.

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We developed porous polyimide PWB which has low dielectric properties for high frequency. Low dielectric properties are possible by using porous technology for polyimide and making air with the lowest dielectric properties hold in the polyimide film. In this research we considered the relation porosity and characteristics of polyimide Our porous polyimide shows low dielectric properties about the same level as PTFE. And we checked that useful thermal and physical properties are possible.

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[in Japanese]

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A bonding sheet with low elastic modulus for semiconductor packages was obtained by using Gore-Tex film, expanded polytetrafluoroethylene. Conventionally, PTFE was used in the electronic materials because of its great dielectric properties. However, this invention is to provide a sheet which can make the best use of its low modulus properties by making PTFE more porous. The material with three-layer structure was made based on this idea. A three-layered bonding sheet for stress relaxation having an expanded PTFE layer with low elastic modulus in the core layer was obtained. By using this bonding sheet in an semiconductor package, the mounting reliability and hygroscopic reliability of the package was improved.

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[in Japanese]

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Recent mobile electric components (for example, the parts of mobile phones, the information infrastructure such as a base station of a cellular and Mobile Multimedia switching System (MMS), and so on) need to process large quantities of information quickly as they have multiple functions. Therefore printed circuit boards with a low dielectric constant and dissipation factor are required to transmit the high frequency and high-speed signals without much loss of these signals. Furthermore, as environmental problems are recognized all over the world, copperclad laminates without halogen compounds are in demand. Thus we have developed a halogen-free copperclad laminate with excellent dielectric properties. Its processability is as good as that of the conventional FR-4, and it can be used under the same conditions.

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[in Japanese]

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The contact material of membrane type for the use of inspection, which can apply to narrow pitches with the low cost, was developed. It has the durability in repeating work up to 1 million runs as to the test result of durability by using QFN(Quad Flat Non-leaded package). In the examination for characteristics of electricity, conductor resistance, resistance voltage and insulation resistance were examined, and as to the above test result, it was confirmed that the standard level is achieved without any problems as probe. Also, as to the test result of peeling test by using cellophane tapes, there was no indication of peeling spots and it was found that nature of adhesion is excellent.

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[in Japanese]

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[in Japanese]

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Rationalization and the processing expense decrease in the manufacturing process become indispensable with the rise of the demand for the optical transmission module by the development of the optical communication net. Then, rationalization by the automation of the characteristic test which is the final process is promoted. However, there were problems that increase of capital investment to the examination equipment for the production capacity improvement, and taking the software development a long period in automating. Then, the measurement control programming tool was developed for shortening the software development period, and the test equipment was constructed with the system configuration which achieved shorter test time. As a result, shortening the test time and shortening the software development period was achieved.

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Optoelectronic (OE) Micro System Integration Technology (OMSIT), which is being developed in Tokyo University of Technology, is presented. OMSIT will replace to conventional packaging based on flip-chip bonding with all-phofolithographic heterogeneous device integration process, realizing cost/resource saving. It will be applied to OE PCB/MCM, optical switching, display, wearable system, and so on. SOLNET, which enables self-organized optical coupling and 3D micro optical network, is also introduced.

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Progress of Active interposer (AIP) which is conversion module between electrical and optical signal is described. AIP is a module by which LSI, VCSEL, and the driver, etc. are three-dimensionally mounted on the interposer substrate, and which is one of development technologies of national project “Research and Development for Super High-density Electronics System Integration”. The model was made for trial purposes aiming at the confirmation of a fundamental structure, and the signal transmission characteristic was evaluated

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[in Japanese]

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Recently the traffic volume of data communication is increasing by the huge growth of the Internet, and the adoption of FTTH (Fiber To The Home) is in the trend that expands. FTTH adopts the single star method using the media converter that is able to achieve the cost reduction in the present. We developed the optical transceiver that is the main part of a media converter. This optical transceiver uses WDM (Wavelength Division Multiplexing) technology, so is able to transmit with the one fiber bi-direction. The package of the transceiver conforms 2×5 style pin arrangement.

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[in Japanese]

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We report a new MEMS-based laser-to-fiber coupling. An integrated MEM platform, which has a thermally-actuated micromirror, a silicon-etched v-groove and flip-chip bonding functions, is successfully fabricated and actuated for beam adjustment from a VCSEL to a fiber. The micromirror has 4.0 degree miximum beam steering angle with the resolution of 0.08 degree/mA. With the steering angle reaching 2.5 degrees, the coupling efficiency improves to 80% from 9% initial efficiency.

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2D scanning micro mirrors with silicon based diaphragms are designed and fabricated to improve the deformation of the mirror plate while actuated at high resonant frequency. In order to yield large actuation force, the PZT structures are developed to be the actuator components. First of all, the scan characteristics of a 1200×500μm² DPZT beam, including displacement and resonant frequency, were measured and verified with the finite element analysis. In the case of a 2D micro mirror with a 500×500μm² mirror plate, the 1D optical scan angle was 8±1 degrees with respect to the actuation of 7.5 Vp (at 850 Hz). After that, the silicon based mirror plate was kept smooth which the surface roughness (Rq) was less than 2μm.

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[in Japanese]

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A compact, angular-rate sensor module has been developed using a flatly supported, quartz sensing element of double T-shaped resonators. The sensing element has both drive and pickup resonators in the same plane of a Z-cut quartz wafer to detect angular-rate motion perpendicular to the plane. Because of good temoerature stability of the quartz, and symmetric structure of the double T-shaped resonators, the sensor module also can achieve small offset drift, high S/N (Signal to Noise ratio), and excellent immunity to vibration noise.

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Intra-body communication by sending very weak electrical current through the human body is studied. Electrical impedance of human body is several kilo hundreds ohm for frequency below 100Hz, and decrease down to several hundreds ohm for over 100kHz. Size and material of the electrodes effect the impedance at low frequencies, but the effect is negligible for transmission using frequencies over several hundreds kHz. Transmission is possible by attaching two electrodes of both transmitter and receiver. This does not form a closed loop circuit including the human body. Transmission efficiency peaks at around 5MHz. We have succeeded in transmitting electrocardiogram signal by using commercial FM modulator/demodulator devices for 10.7MHz.

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Demand for various glass-parts is now increasing rapidly as information technology is developed. Precise Glass Molding Method is one of the best processing methods to make precise parts and lower the price of glass-parts for mass-producing. Now many Aspherical lenses for camera are manufactured by glass molding method. We describe about construction and features of our glass-molding machine GMP series, glass molding applications, and the mold technology. Concerning the glass molding applications, we describe about insertion molding and molding of fiber-array and amorphous alloy. We also consider about the new applications of glass molding.

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Copper bump bonding (CBB) process is under development for 3D stacked LSI, which enables the interconnections between the copper bumps with electroless thin tin-plating and the copper through-hole electrodes in 20μm-pitch. In this paper, the micro-bumping technologies and the high-precision bonding process were evaluated for the advanced hyperfine interconnections approximately in 5μm-pitch. The subjects for bumping process were found out, and the thermal stress analysis on the specification of the equipment proved the impact of the process at low-temperature for high-precision interconnections. Moreover, the micro-joint was confirmed with copper bumps in 20μm-pitch utilizing the diffusion bonding at 150°C as low-temperature. This work was performed by ASET supported by NEDO.

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[in Japanese]

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The fritting of thin oxide on metal surface is indispensable to realize MEMS probe cards, because each microprobe cannot endure the force required to break the oxide on the surface of IC pads mechanically. In order to clarify the force required for fritting-contact make, the relationship between contact forces and the fritting has been investigated using a newly developed measurement system which can detect the contact force precisely. As a result, we found that the fritting process makes it possible to realize the low-resistance contact to Al pad, even when the contact force is 10 μN.

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