A practical method for predicting gold-wire deformation during the transfer molding process of semiconductor devices has been developed. In this study, common parameters for estimating values of wire deformation of the BGA (Ball Grid Array) package and the QFP (Quad Flat Package) used in previous reports were investigated. First, we examined the parameter λ, which was already derived as a function of resin velocity component perpendicular to the center of each wire, resin flow time at the center of each wire, apparent resin viscosity in the mold cavity, gold wire dimensions such as loop height, actual length and diameter, and Young's modulus for the gold wire. In the case of the BGA package, the maximum horizontal displacement, δ_max, was found to be a linear function of λ up to around δ_max=0.4mm with an intersection at the origin of the coordinate axes, On the other hand, for the QFP, a deviation from linearing was found for δ_max exceeding 0.16mm. Next, both δ_max and λ were divided by the actual length of each gold wire, and these values were defined as new parameters ζ and φ, respectively. By introducing these parameters, all the data were found to fit well by a straight line up to around ζ=8% with a subsequent a saturation curve. Three empirical models to represent the relationship between ζ and φ were obtained. Using these models, values of ζ were accurately calculated.

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Ferrules are key components of fiber-optic connectors. We successfully molded plastic ferrules for single-mode applications by injection molding process using LCP (Liquid Crystalline Polymer composite). In this paper, we investigated the outer diameter precision profile of plastic ferrules and the mold structure dependence of the dimensional accuracy of the ferrules. Using 3-dimensional (3D) flow analysis, we calculated the temperature and density distribution profiles of ferrules during the cooling process. Two types of mold structures were investigated, Y-type model (conventional model) and M-type model (newly proposed model). For the Y-type model, a large temperature and density distribution was observed especially in the ferrule front side. For the M-type model, the inhomogeneity was decreased dramatically.
In order to validate the 3D simulation predictions, molding experiments were performed. For the Y-type molded ferrule, a sink mark of about 5μm was observed at the ferrule front side. On the other hand, the sink mark disappeared for the M-type ferrule and the outer diameter change along the length was within ±1μm. The proposed M-type structure proved to be effective for the molding of high precision plastic ferrules.

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