1. Technical Field
The present invention relates to a semiconductor device and a method for manufacturing the semiconductor device.
2. Related Art
In recent years, there has been an increasing demand for semiconductor devices (semiconductor packages (hereinafter referred to as packages)) each having a semiconductor chip (hereinafter referred to as a chip) and a semiconductor substrate (hereinafter referred to as a substrate) electrically connected to each other by a flip-chip process. Such semiconductor packages are demanded as small-area, thin packages that can be mounted at a high density.
The flip-chip process can be performed in the following manner. First, the surface (the circuit formation face) of a chip and the interconnect face (the side on which the interconnects for the chip are formed) of a substrate are placed to face each other. The electrode pads formed on the surface of the chip are then bonded (flip-chip bonded) to the electrode pads formed on the interconnects of the substrate via bumps (connection media) made of solder, gold, copper, or the like.
The bumps for the flip-chip bonding are formed beforehand on the electrode pads of the chip or the electrode pads of the substrate, and have a certain height (5 to 100 μm). Therefore, after the chip is bonded to the substrate, a space is formed between the surface of the chip and the substrate.
The space is normally filled with a resin. The resin can physically protect the joining portions among the electrode pads of the chip, the bumps, and the electrode pads of the substrate. The resin can also prevent short-circuiting between adjacent electrodes due to remelting of the bumps and bridging between adjacent joining portions at the high temperature to which the package is exposed at the time of mounting.
Japanese Laid-Open Patent Publication No. 08-195414 discloses a package that is formed by placing the chip surface (the circuit surface) and the substrate interconnect face (the chip bonding face) to face each other, and flip-chip bonding the chip to the substrate. In this package, a first resin is placed in a first region that is surrounded by the outermost circumferential bumps, and a second resin is placed in a second region that is a region outside the outermost circumferential bumps. At least, the amount, the maximum particle size, or the mean particle size of the inorganic filler contained in the first resin is smaller than that of the second resin.
Japanese Laid-Open Patent Publication No. 08-195414 discloses that, in this structure, the modulus of elasticity of the first resin placed in the first region becomes lower while the thermal expansion coefficient of the first resin becomes higher, and accordingly, the shear deformation at the end portions of the resins caused by the temperature cycling can be made smaller. By the technique disclosed in Japanese Laid-Open Patent Publication No. 08-195414, the modulus of elasticity of the first resin is set at a low value, so as to minimize the residual stress between the chip and the first resin. Meanwhile, the thermal expansion coefficient of the second resin in contact with the end portions of the chip is set at a low value, so as to prevent a concentration of stress strain caused by thermal stress.
Japanese Laid-Open Patent Publication No. 08-195414 also discloses that, in this structure, the residual stress between the chip and the first resin can be made smaller, and detachment of the chip due to the residual stress can be restrained. Also, it is possible to prevent cracks and the like caused by a concentration of stress at the end faces of the chip due to the difference in thermal expansion coefficient.
Japanese Laid-Open Patent Publication No. 08-195414 also discloses that the amount of the inorganic filler contained in the second resin placed outside the bumps should be made larger than that in the first resin. By doing so, the moisture penetration path can be blocked, and the reliability in terms of moisture resistance is improved. Japanese Laid-Open Patent Publication No. 08-195414 further discloses that only the particle size of the inorganic filler of the first resin placed inside the bumps should be made smaller. By doing so, breaking of the chip can be restrained while the moisture blocking effect is maintained, and the injection performance of the resin can be improved.