Novel Flip Chip Technologies for Ultra Thin Chip
Telecommunication equipment that supports high-level information networks is being made portable, small and lightweight. Thus, the miniaturization of semiconductor devices is necessary, and chip thinning and flip chip technologies are key in achieving it. The typical flip chip manufacturing steps for thin semiconductor devices are as follows. First, semiconductor elements are formed on a wafer. Surface protective tape is attached to the surface of the wafer and backside grinding is performed to make the wafer thin. Then, dicing tape is attached to the backside of the wafer and the wafer is diced from the surface side, using a diamond blade, and divided into chips. Then, the chips are picked up, using pick up needles and bumps are formed on the surface of the chip. Next, seal resin is attached to a substrate, then the surface of the chip is attached to the substrate with the seal resin and flip chip interconnection and sealing are performed to mount the chip. This manufacturing step has some problems. In this paper, a novel thin package manufacturing process is described.
Development of 3-dimensional module package, "System Block Module"
As the mobile electronics equipment moves toward higher performance and miniaturizing, each IC package is required to be stacked for saving a package mounting area on a system board. This paper describes a newly developed 3-dimensional module package using the technology of the silicon device thinning, micro flip chip bonding and two types of via connection of print circuit board for vertical wirings. These technology has realized the high density packaging of over 4 ICs stacking for practical use.
Design of reinforced concrete lining in pressure tunnels, considering thermal effects and jointed rockmass
Abstract Jaeger's theory (Jaeger, Rock Mechanics and Rock Engineering , Cambridge University Press, 1972) of the design of the lining for a pressure tunnel applies to a tunnel located in an isotropic, homogeneous and elastic medium. The theory is derived from the elasticity equations for the plane stress condition. In this paper, Jaeger's theory is extended to a plane strain situation. Also included is a discussion of the effects of a uniform increase (or decrease) in the lining temperature, jointed rockmass, cracking of the tunnel lining, and cracking of the rockmass around the opening. Tables are presented for the modulus of subgrade reaction for various rockmass conditions and for rock sharing pressures for various lining conditions. The reduction factor to include the effect of joints in rockmass is derived by the analysis of a numerical model of the lined tunnel by the finite-infinite-interface element method.