Tape Ball Grid Array Package Research Articles

A Numerical Analysis of the Thermal Performance of Single Sided and Back-to-Back Tape Ball Grid Array Packages

This paper presents the results of a comprehensive numerical study of the thermal performance of Tape Ball Grid Array package mounted on one side of a printed circuit board as well as packages mounted in back-to-back and offset configurations. A cover plate is attached to the back side of the chips to enhance heat transfer from the module. The assembled organic carrier is placed in a vertical channel. A conjugate heat transfer model is used which accounts for conduction in the packages and the card and convection in the surrounding air. The effect of location of the modules on a card with zero, one and two power planes is evaluated for thermal performance. Heat dissipation is studied for forced convection (2, 1, and 0.5m∕s). Comparison is made for single sided and back-to-back cases.

Influence of Material Combinations on Delamination Failures in a Cavity-Down TBGA Package

In this study, we have examined the occurrence of different failure types depending on the compound and die-attach material choice in a cavity-down tape ball grid array (TBGA) package. Qualification of the different products is performed by temperature cycle tests to trigger the different failure modes. Samples are decapped to examine the occurrence of passivation crack, wire shift, and/or wire break. Scanning acoustic microscope measurements are performed to examine the occurrence of delamination. Meanwhile, a parametric three-dimensional finite element model is developed to predict the delamination driving stresses for the different material combinations in the cavity-down TBGA package. In some combinations of compound and die-attach, the package performed poor with only one combination without failures. The results of the finite element calculations indicated the possibility of interfacial delamination for different material combinations. Our results show that the reliability of the cavity-down TBGA package is strongly depending on the material combinations, and the developed simulation models can be used to assess the possibility of delamination failures as the consequence of using different material combinations. Using these simulation techniques, cost- and time-expensive reliability tests can be reduced to a minimum.

Thermal design of a broadband communication system with detailed modeling of TBGA packages

This paper presents a thermal modeling of a broadband network communication box partitioned into two stacked modules. A printed circuit board (PCB) is inside each module where an array of 16 tape ball grid array (TBGA) packages is surface mounted to the PCB. The TBGA package dissipates 6 W power each. In addition, 12 W of power is dissipated from four plastic ball grid array (PBGA) packages on the PCB. Pin-fin heat sinks are attached to the TBGA packages using silica-filled epoxy to enhance heat dissipation. Pin-fin heat sinks are also attached to the PBGA packages. Two exhaust fans are mounted at the flow exit to draw ambient air into the system at approximately 200 linear feet per minute (LFM) of velocity. The full Navier–Stokes equations for airflow are solved to simulate the forced convection cooling in the electronic module. Buoyancy effect was considered in the numerical model by incorporating Boussinesq-approximation. The TBGA packages are modeled in detail in order to obtain the package junction temperatures for system reliability evaluation and thermal design optimization. Detailed models of the attached pin-fin heat sinks and the epoxy interfaces are also utilized in this study. Compact heat sink model composed of a base plate and a resistance fluid volume is applied to model heat dissipation from the heat sinks attached to the four PBGA packages. System fan curve is used to simulate the fan operating conditions. The effect of changing system thermal design on the TBGA package junction temperatures as well as the hydraulic operating conditions of the system fans are examined and reported herein. The effect of radiation heat transfer is also examined. The importance of detailed modeling of the high power TBGA packages is demonstrated in this study. Simulation results were compared with JEDEC thermal test data under similar conditions of airflow.

Design of a Low‐cost Wire Bond Tape Ball Grid Array Package

Tape ball grid array (TBGA) packages offer many of the advantages of plastic BGAs, namely excellent durability, improved board space utilisation and ease of surface mount assembly along with the associated yield improvements. TBGA packages go a step further, however, and offer the added benefits of improved signal integrity, better heat dissipation, and extendability to higher pin counts. This paper outlines the design and material selection process to produce a low‐cost TBGA which allows the wire bonding of a die. This type of package offers an attractive solution for applications requiring mid to high I/O capability and good electrical and thermal properties. Preliminary results have demonstrated the feasibility of wire bonding to this package at temperatures up to 200°C.