Yung Kang Shen

AN ANALYSIS OF THE THREE-DIMENSIONAL MICRO-INJECTION MOLDING

Micro system technology (MST) is including Optic, Mechanism, Electricity, Material, Control and Chemistry, etc. It can miniaturize product and increase its function, quality, reliability and add-value. The size of micro product is closing to nanometer. Micro-injection molding is a branch of micro system technology. Actually, the research of micro-injection molding is just beginning on the world. In this study, numerical simulations of three-dimensional micro-injection molding are performed. The governing differential equations are discredited by using control volume finite element method. The analysis with different polymers (such as PP PA POM) process parameters (injection time mold temperature injection temperature and injection pressure) uses to simulate the micro-gear for example. In order to obtain optimum result, the simulation introduces Taguchi method to discuss the influence of each parameter in micro-injection molding. In this study, the results show that the mold temperature is the most important factor on process parameters. The mold temperature on micro-injection molding is higher than the glass transition temperature of plastic material.

Three-dimensional non-Newtonian computations of micro-injection molding with the finite element method

Micro-injection molding is a branch of micro-electromechanical system (MEMS) technology. Actually, the research of micro-injection molding is just beginning in the world. In this study, three-dimensional non-Newtonian computations of micro-injection molding were performed. The governing differential equations were discredited by using control volume finite element method (CVFEM). The analysis with different polymers (such as PS, PC, PMMA), process parameters (injection time mold temperature injection temperature and injection pressure) uses to simulate the micro-house for example. In order to obtain optimum result, the simulation introduces Taguchi method to discuss the influence of each parameter in micro-injection molding. In this study, the results show that the mold temperature is the most important factor on process parameters. The mold temperature on micro-injection molding is higher than the glass transition temperature of plastic material. The best suitable material is PMMA.

Comparison of the results for semisolid and plastic injection molding process

Abstract Understanding the time-dependent flow behavior of semisolid and plastic materials is essential for the injection molding. The 3C (Computer, Communication, Consumer) product is more light, thin, short and small on today. Traditional injection molding uses the plastic for the shell of 3C product. Because the EMI, good heat dissipation etc., the magnesium for the shell of 3C product is more increasing now. The properties of plastic are shear-thinning. The properties of magnesium are shear-thickening and it injects the mold by semisolid form. Therefore, the situation of injection molding between plastic and magnesium is very different. This paper uses the CAE software (MoldFlow) to analysis the result with different materials (ABS, ABS/PC, Mg), different processing parameters (injection temperature, mold temperature, injection pressure, injection time), and different thickness (1.0mm, 0.9mm). In order to obtain the optimum results, the simulation introduces Taguchi method to discuss the influence of each parameter in injection molding.

Brightness field distributions of microlens arrays using micro molding

This study describes the brightness field distributions of microlens arrays fabricated by micro injection molding (μIM) and micro injection-compression molding (μICM). The process for fabricating microlens arrays used room-temperature imprint lithography, photoresist reflow, electroforming, μIM, μICM, and optical properties measurement. Analytical results indicate that the brightness field distribution of the molded microlens arrays generated by μICM is better than those made using μIM. Our results further demonstrate that mold temperature is the most important processing parameter for brightness field distribution of molded microlens arrays made by μIM or μICM.

The study on polymer melt front, gas front and solid layer in filling stage of gas-assisted injection molding

The algorithms are developed to predict the polymer melt front, gas front and solid layer in gas-assisted injection molding. The simulation of two-dimensional, transient, non-isothermal and high viscous flow between two parallel plates with the generalized Newtonian fluid is presented in detail. During solidification while an injection mold fills, a solid-liquid interface moves and a two-phase zone exists; an enthalpy model is used to predict this interface in the two-phase flow problem. The model takes into account the three-phase flow including the effects of the gas front, solid layer and polymer melt front.

Study on mold flow analysis of flip chip package

Abstract Flip chip package is the most important technology in IC package for the necessary for scale, velocity and cost by the development of semiconductor technology and the innovation of computer product. It has the advantage of low cost, low interface and small volume in IC package. Since the flip chip package is developed by IBM Company in 1960. The meaning of flip chip package is turn over the chip for the connection between the metal conductor and PCB plate. This paper is indicated that the analysis package for the solder ball and chip for mold flow analysis. The analysis uses the sphere type, elliptic type of solder ball for column-row and cross arrangement. The package material uses for epoxy. The injection point uses for the corner, 1/4 side and central injection location. The injection process uses for different parameters (mold temperature, injection temperature, injection pressure, injection time). The results discuss by the distribution of injection pressure, the pressure drop, temperature, filling time, welding line and air trap. It shows that the injection temperature and mold temperature are the mold factor for processing parameters. The results show that the air trap and welding line of corner injection are smaller then central and 1/4 side injection. It indicates that the corner injection is better than central and 1/4 side injection.

STUDY ON WARPAGE AND SHRINKAGE OF FLIP CHIP ENCAPSULATION PROCESS

Flip chip encapsulation process is currently the most advanced package technology due to its ability to provide a large number of I/O interconnections and improve electrical performance. It has the advantage of low cost, low interface and small volume in IC package. This paper indicates that the analysis for package of the solder ball chip and substrate. A finite element simulation of moving boundaries in a three-dimensional inertia-free, incompressible flow is presented. The injection situation uses for one line injection, L line injection, U line injection and central point injection location. The injection process uses for different parameters (mold temperature, injection temperature, injection pressure, injection time). When the injection molding is end, then also the finite element method to simulate the warpage and shrinkage for solder ball . chip and substrate. The results show that the warpage is smallest on U line injection.

Analysis of the Mold Filling Process on Flip Chip Package

Flip chip package is the most important technology in IC package in terms of scale, velocity and cost in the development of semiconductor technology and the innovation of computer product. It has the advantage of low cost, low interface and small volume in IC package. This paper describes the analysis package of the solder ball and microchip for mold flow simulation (3D, midplane) and experiment. The numerical simulation of mold filling process is based on the concept of control volume finite element method. The injection point uses the corner, 1/4 side and central injection location. The injection process uses different parameters (mold temperature, injection temperature, injection pressure and injection time). For processing situation, the best result is from central injection, then 1/4 side injection and then corner injection. The results also show that the filling situation for 3D numerical simulation is closer to experiment.

Analysis of the Replication Properties of Lightguiding Plate for Micro Injection Compression Molding

This paper presents the application of microstructure replication of lightguiding plate for micro injection compression molding (MICM). The lightguiding plate is applied on LCD of two inch of digital camera. Its radius of micro-structure is from 100μm to 300μm by linearity expansion. The material of lightguiding plate is PMMA. This paper discusses the replication properties for different process parameters by single-parameter method for micro injection compression molding. The important process parameters of replication properties are the mold temperature, compression distance and melt temperature in micro injection compression molding. The mold temperature is the most significant factor of replication properties of microstructure of lightguiding plate for micro injection compression molding.

Flow Visualization of Solder Ball Arrangement for Underfill Encapsulation of Flip Chip

The flip chip package has the advantages of low cost, low interface, and small volume in IC package. This study describes the analysis of underfill encapsulation between solder balls and microchip by experiment and 3D numerical simulation. The numerical simulation of underfill encapsulation is based on the concept of the control volume finite element method. The parameters of injection situation are used for central point, one line, L-line, and U-line injection types. The different processing parameters (solder ball arrangement, injection pressure, solder ball size, and injection situation) are used for underfill encapsulation. The results show that the free surface shape of the experiment is closer to that of the 3D numerical simulation on the plane flow situation for underfill encapsulation. The injection situation of L-line is the best underfill encapsulation of flip chip irrespective of the different arrangement of solder ball and size of the solder ball. The flow time has the biggest value for the different size of solder ball on an alternate arrangement of the solder ball. The flow time decreases as injection pressure increases. The free surface on the thickness direction is concave for the underfill process of the experiment. The contact angle of the free surface is the same for different injection pressures in underfill encapsulation. This situation indicates that the capillary effect dominates the flow situation in the underfill process.