Tetsu Tanaka

Bio: Tetsu Tanaka is an academic researcher from Tohoku University. The author has contributed to research in topics: Wafer & Chip. The author has an hindex of 38, co-authored 406 publications receiving 10375 citations. Previous affiliations of Tetsu Tanaka include NTT DoCoMo & Tokyo Medical and Dental University.

A new temporary bonding technology with spin-on glass and hydrogenated amorphous Si for 3D LSIs

Abstract: A new temporary bonding technology has been demonstrated, where both spin-on glass (SOG) and hydrogenated amorphous silicon (a-Si:H) were used as a bonding layer and as a debonding layer, respectively. Square chips were bonded to a glass wafer through the SOG layer and a-Si:H layer. The SOG bonding was capable of withstanding chip thinning and high-temperature chemical vapor deposition (CVD) processes. A XeCl excimer laser was irradiated to the a-Si:H layer through the glass wafers for debonding the chips. A novel via-last/backside-via 3D integration process using temporary SOG bonding was also proposed for advanced multichip-to-wafer 3D integration with self-assembly.

New three-dimensional integration technology to achieve a super chip

Abstract: We have proposed a new three-dimensional (3D) integration technology based on a chip-to-wafer bonding method which is called a super chip integration technology. Various kinds of chips such as processor chip, memory chips, analog IC chip and sensor chips which are fabricated by different technologies can be vertically stacked into a 3D LSI chip by using a super chip integration technology. Such 3D LSI chip is called a super chip. Various kinds of chips with different chip size, chip thickness and material can be vertically stacked in the super chip integration technology. To establish the super chip integration technology, several key technologies of vertical interconnection formation, chip alignment and bonding, adhesive injection, and chip thinning and planarization were developed. By using the super chip integration technology, three-layer stacked LSI chips with vertical interconnections were successfully fabricated

Impact of 3-D integration process on memory retention characteristics in thinned DRAM chip for 3-D memory

Abstract: The Young's modulus (E) of Si substrate begins to noticeably decrease below 50-μm thickness. The Young's modulus in 30-μm thick Si substrate decreased by approximately 30% compared to the modulus of 50-μm thickness. In 30-μm thick Si substrate, the lattice structure of Si substrate is highly distorted. Large distortion of the lattice structure induces the Young's modulus reduction, consequently weakens the mechanical strength. A DRAM chip of 200-μm thickness was bonded to a Si interposer and thinned down to 50/40/30/20-μm thickness, respectively. The retention characteristics of DRAM cell are degraded depending on the decreased chip thickness, especially dramatically degraded below 50-μm thickness. The retention time of DRAM cell in 20-μm thick chip is shortened by approximately 40% compared to the 50-μm thick chip, regardless of the well structure (triple-well, twin-well). The distortion of the lattice structure in the thin chip effects a minority carrier generation lifetime, consequently shortening the retention time of DRAM cell.

Deciphering the biology of Mycobacterium tuberculosis from the complete genome sequence

Abstract: Countless millions of people have died from tuberculosis, a chronic infectious disease caused by the tubercle bacillus. The complete genome sequence of the best-characterized strain of Mycobacterium tuberculosis, H37Rv, has been determined and analysed in order to improve our understanding of the biology of this slow-growing pathogen and to help the conception of new prophylactic and therapeutic interventions. The genome comprises 4,411,529 base pairs, contains around 4,000 genes, and has a very high guanine + cytosine content that is reflected in the biased amino-acid content of the proteins. M. tuberculosis differs radically from other bacteria in that a very large portion of its coding capacity is devoted to the production of enzymes involved in lipogenesis and lipolysis, and to two new families of glycine-rich proteins with a repetitive structure that may represent a source of antigenic variation.

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

Abstract: BackgroundExperimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. MethodsWe conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. ResultsAt 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in t...

Complete genome sequence of Pseudomonas aeruginosa PAO1, an opportunistic pathogen.

Abstract: Pseudomonas aeruginosa is a ubiquitous environmental bacterium that is one of the top three causes of opportunistic human infections. A major factor in its prominence as a pathogen is its intrinsic resistance to antibiotics and disinfectants. Here we report the complete sequence of P. aeruginosa strain PAO1. At 6.3 million base pairs, this is the largest bacterial genome sequenced, and the sequence provides insights into the basis of the versatility and intrinsic drug resistance of P. aeruginosa. Consistent with its larger genome size and environmental adaptability, P. aeruginosa contains the highest proportion of regulatory genes observed for a bacterial genome and a large number of genes involved in the catabolism, transport and efflux of organic compounds as well as four potential chemotaxis systems. We propose that the size and complexity of the P. aeruginosa genome reflect an evolutionary adaptation permitting it to thrive in diverse environments and resist the effects of a variety of antimicrobial substances.