Abstract: A printed wiring board and an electronic device using the same with which the formation of cracks in base portions of projecting external electrodes formed on lands on the printed wiring,board is certainly prevented. With respect to a printed wiring board 11 having lands 16 formed in a wiring pattern where external electrodes 13 are to be formed and a pattern-protecting film 17 having openings 17a where the external electrodes 13 are to be formed, the opening diameter D1 of the openings 17a in the pattern-protecting film 17 is set greater by a predetermined dimension than the external diameter D2 of the lands 16 and a gap is thereby provided between each of the external electrodes 13 and the pattern-protecting film 17 so that the external electrodes 13 and the pattern-protecting film 17 do not make contact with each other and as a result there is no cracking of the external electrodes 13 caused by differential thermal expansion of the external electrodes 13 and the pattern-protecting film 17.

Abstract: A gate portion constituting a gate of a resin molding die is made of a hard alloy having a hardness greater than the predetermined hardness in the iron-based hard alloy used to form a cavity block and a center block. Opposing surfaces of the cavity block halves include a polytetrafluoroethylene layer at least at the portions thereof which contact portions of the lead frame in a semiconductor encapsulation molding apparatus.

Abstract: A semiconductor device is fabricated by placing a semiconductor chip in a lead frame which has no die pad. Electrodes of the chip are connected by bonding wires to respective lead fingers. Additionally, the lead frame has movement restricting fingers which limit horizontal movement of the chip within the lead frame during injection of resin into a mold surrounding the chip. Furthermore, the mold has horizontal movement restricting projections to limit vertical movement of the chip within the mold cavity. The restriction on horizontal and vertical movement of the chip reduces the risk of the bonding wires being broken or short circuited during the resin injection process.

Abstract: A semiconductor device including a lead frame provided with a die pad and a plurality of leads arranged around the die pad, a semiconductor element mounted on the die pad, and a molding resin for sealing the semiconductor element. A spacing defined between the die pad and the leads is sized, i.e. made very small, that a flow velocity of a first portion of the molding resin flowing in a peripheral region of the semiconductor element becomes substantially equal to a flow velocity of a second portion of the molding resin flowing on at least an upper surface of the semiconductor element. That is, the first portion of the molding resin flowing in the peripheral region of the semiconductor element receives resistance due to the very small spacing between the die pad and the leads. Accordingly, the flow of the molding resin as a whole can be made uniform to thereby reduce or eliminate the generation of voids in the molding resin. As a result, reliability and productivity of the semiconductor device can be improved.

Abstract: A semiconductor device is fabricated by placing a semiconductor chip in a lead frame which has no die pad. Electrodes of the chip are connected by bonding wires to respective lead fingers. Additionally, the lead frame has movement restricting fingers which limit horizontal movement of the chip within the lead frame during injection of resin into a mold surrounding the chip. Furthermore, the mold has horizontal movement restricting projections to limit vertical movement of the chip within the mold cavity. The restriction on horizontal and vertical movement of the chip reduces the risk of the bonding wires being broken or short circuited during the resin injection process.