Torsten Hauck

An RCP Packaged Transceiver Chipset for Automotive LRR and SRR Systems in SiGe BiCMOS Technology

We present a transceiver chipset consisting of a four channel receiver (Rx) and a single-channel transmitter (Tx) designed in a 200-GHz SiGe BiCMOS technology. Each Rx channel has a conversion gain of 19 dB with a typical single sideband noise figure of 10 dB at 1-MHz offset. The Tx includes two exclusively-enabled voltage-controlled oscillators on the same die to switch between two bands at 76-77 and 77-81 GHz. The phase noise is -97 dBc/Hz at 1-MHz offset. On-wafer, the output power is 2 × 13 dBm. At 3.3-V supply, the Rx chip draws 240 mA, while the Tx draws 530 mA. The power dissipation for the complete chipset is 2.5 W. The two chips are used as vehicles for a 77-GHz package test. The chips are packaged using the redistribution chip package technology. We compare on-wafer measurements with on-board results. The loss at the RF port due to the transition in the package results to be less than 1 dB at 77 GHz. The results demonstrate an excellent potential of the presented millimeter-wave package concept for millimeter-wave applications.

Weibull statistics for multiple flaw distributions and its application in silicon fracture prediction

Focus of this paper is the prediction of silicon fracture in microchips of electronic devices. The strength of silicon chips strongly depends on flaw distributions introduced by wafer manufacturing processes. Consequently strength data scatter and a probabilistic approach to failure is required. For this purpose Weibull theory will be used and combined with test procedures and numerical tools for prediction of fracture probability. Multiple active flaw distributions on the surface of the chip and its sawing edges will be considered. Test procedures for strength measurements and Weibull parameter extraction will be presented. Failure prediction will be demonstrated for a microchip showing multiple active flaw distributions which is assembled on a leadframe.

A New Approach to Boundary Condition Independent Compact Dynamic Thermal Models

The paper introduces a new method for the generation of boundary condition independent dynamic thermal compact models. The procedure starts with a description of the component (e.g. semiconductor package, printed circuit board, etc.) and associated thermal ports at the continuous field level with a finite element code. Using order reduction methods a low order state space model is generated which represents the thermal behavior of the component. Additional matrix manipulations are applied to transform the state space model into a Kirchhoffian network that provides the transfer functions between all thermal ports. The method is demonstrated on an example from the semiconductor industry with a device package placed on a printed circuit board. By means of model coupling thermal simulation of the system is performed using the new boundary condition independent compact model. The results are finally compared to appropriate finite element simulations.

Simulation of Wafer Probing Process Considering Probe Needle Dynamics

One key failure root cause during wafer production is the electrical test by probing all interconnects of each die of the wafer. The probing process can result in excessive damage of the back end of line (BEOL) wafer layers underneath the probe pad, especially if brittle low-k dielectrics are used. The industry is trying to reduce design limitations for these under pad areas. A 3D sub-modeling simulation approach has been used to investigate stress states in layers below the probe pad. The dynamic behavior of the needle is determined by modal analysis. Its representation and calculation is done by an analytical model using the modal superposition method. These small, specialized simulation models help to distribute the simulation effort, by handling specific aspects of the real process, such as the contact problem, needle dynamics and homogenization of fine structures. The results showed that the needle dynamics can be neglected during further studies. The static load due to the maximum displacement of the needle tip during the probe event is one magnitude higher then any dynamic driven load.

Simple Methods for the Durability Assessment of Microelectronic Solders

This paper presents a simple method, based on a 1-D model, that allows us to assess the impact of an essentially arbitrary thermal cycle test on the creep strain and energy dissipation in solder materials. Such tests are typically performed in order to assess the reliability and the lifetime of solders used for electrical and mechanical connection of microelectronic components. The method is applied to study the dissipated energy in terms of the stress-strain hysteresis in various solders, both lead-free as well as lead-containing. A first comparison between a full finite element study of the stress-strain hysteresis loop and the simplified approach is performed. It is shown that both lead to the same trends regarding creep strains and energy dissipation, however, the absolute values differ. For this reason a re-scaling procedure is proposed which allows to use the simplified approach for quantitative predictions.

Large deformation of beam columns - a closed form solution and design guide for vertical buckling probe needles

Higher pin count and reduced pitch along with increased wafer size set new demands to fine pitch wafer probe technology. Vertical buckling probe needles are one of the available concepts. The required elasticity for contacting the pad is achieved by buckling of the needles. The buckling mode guarantees a consistent contact pressure over a large range of overtravel and thus allows for an optimal tolerance even under changing planarity conditions of the wafer. However, the dimensioning of a buckling needle for specified contact forces seems impossible for designers. Therefore, the authors present closed form solutions for large deformation of buckling beam columns. It is an extension of the Euler buckling cases known from textbooks and goes back to a publication of Thimoshenko regarding the first Euler case. This solution will now be discussed and extended to the fourth Euler case. Its applications will be demonstrated for a vertical buckling probe needle with one end built in and the other end guided by a guide plate. A closed form solution of the force-deflection characteristic will be presented and compared with geometrical nonlinear finite element analysis.

The influence of packaging technologies on the performance of inertial MEMS sensors

The paper is focused on the influence of packaging technologies on the performance of inertial MEMS sensors. System simulations of MEMS are vital to evaluate and optimize the interplay of transducer cells with the sensor electronics. Special emphasis must be put on packaging aspects in order to assess the impact of environmental and operating conditions on functional parameters as capacitance offset or loss of sensitivity affected by thermal-mechanical stress or structural deformation. This article presents modern reduced order modeling technologies which extract fast and accurate behavioral models from a series of finite element runs which can directly be used in Matlab/Simulink or Verilog-A for system design.

Dynamic macromodels for sensor devices

The focus of this paper is the generation of macromodels that capture all relevant information of sensor devices. The approach starts with a finite element model, which considers electromechanical coupling and fluid-structure interaction at the continuous-field level. ANSYS/Multiphysics reduced order model (ROM) procedures are used to reduce the large amount of degrees of freedom of the device model. The procedure is based on a linear modal analysis and the representation of the state variables in terms of a small series of basis functions. The resulting device models are suitable for system simulation. The generation pass and the use of such models will be demonstrated for capacitive sensor devices. Results are compared with analytical solutions and experimental data. The presented model generation path is part of the sensor design flow. Device models are used for optimization and circuit design.

Thermal Modeling Improvements using substrate ECAD integration

With requirements of higher power density and smaller package size, thermal management of electronic packages has become increasingly challenging since last decade. With several design parameters playing an important role in evaluation of thermal characterization parameter, design approximations can lead to significant error. Substrate design is a critical aspect of the thermal model and the current state-of-the-art varies from approximate copper percentage inclusions to manually building traces to capture important geometrical features. Typically, these methods are prone to approximation errors and are also time consuming for building geometric models. An alternate method proposed is to use direct substrate ECAD integration in the package model that significantly improves the thermal modeling efficiency.

Bond wire design for eXtreme Switch devices

Freescales third-generation eXtreme Switch devices set performance standards for automotive lighting. They are tailored to drive high-intensity discharge (HID) xenon, halogen and light-emitting diode (LED) lamps. For example, a halogen lamp draws high levels of current when first turned on, but much less once it has stabilized. The ICs therefor allow the lamps to draw high levels of current when needed at turn-on but less during operation. Hence, these devices have to withstand the event of an inrush current each time a lamp is switched on. Package and wire bond design have to consider the transient characteristics of Joule heating and heat transfer. The authors developed an approach for the current carrying analysis of bond wires in power packages. It is based on closed form solutions of the heat equation at single current pulse, repeated current pulses or arbitrary inrush current profiles. This paper focuses on the analysis of Joule heating in bond wires. We will solve the initial and boundary value problem for the Joule heating at an inrush current pulse. The solution will be validated with thermo-electric finite element simulation. We will then draw conclusions for the wire bond design.