Adaptive fuzzy process control of integrated circuit wire bonding

One step in the assembly of integrated circuits is wire bonding, requiring expert knowledge to optimize critical process characteristics. This paper describes a fuzzy logic controller which sets parameters for the wire bonding process for gold ball wire bonds, specifically controlling bonded ball diameter and shear strength density. While the focus is on control of ball bonds, the method is general and may be applied to other bonding methods with minor modifications. The design of the fuzzy engine and the development of rules based on both operator experience and textual sources are discussed. An adaptation technique is developed to tune the controller's membership functions based on the measured results of the process. The controller has been tested on actual devices in an industrial setting; results show improved process control in terms of consistency and reduced operator adjustment     

Wireless communication in a flip-chip package using integrated antennas on silicon substrates

An intrachip wireless interconnect using integrated antennas is demonstrated in a flip-chip ball grid array package. The wireless interconnect consists of a transmitter-receiver pair, which is fabricated in a 0.18-/spl mu/m CMOS process. A 15-GHz signal is generated and broadcasted across the integrated circuit. The signal is picked up by a receiver 4 mm away on the same integrated circuit and frequency divided by eight to produce a 1.875-GHz local clock signal. The interconnection is also demonstrated between a transmitting antenna and a packaged receiver 40 cm away from the transmitting antenna. Demonstration of intrachip wireless interconnects in a package has been considered the ultimate test for this technology.     

Highly linear-polarized external cavity lasers hybrid integrated on planar lightwave circuit platform

We propose and demonstrate, for the first time, a highly linear-polarized external cavity laser (ECL) integrated on planar lightwave circuit (PLC) with an in-PLC polarizer designed to improve polarization extinction ratio (PER). The in-PLC polarizer based on a 45/spl deg/-tilted grating was simply formed in the laser cavity composed of a Fabry-Pe/spl acute/rot laser diode and a Bragg grating. The proposed ECL exhibited a PER value as high as 30 dB and single longitudinal mode oscillation with a high sidemode suppression ratio of 50 dB at 1310 nm.     

The effect of some composite structures on the thermal resistance of substrates and integrated circuit chips

An exact three-dimensional solution to the differential equation for steady-state heat transfer in composite media has been derived. Detailed results for 0.050-in-square chips mounted on 1- and 2-in-square substrates show that the thermal resistance of alumina substrates may be expected to increase by as much as 80 percent upon application of a glaze to the surface. The thermal resistances of beam lead chips varying in size from 0.050-to 0.150-in square are determined for chip-substrate interface distances from 0.0005 to 0.002 in, both with and without a thermal conducting compound as the interface media.     

Atmospheric pressure chemical vapor deposition of blanket tungsten films on silicon substrates for integrated circuit applications

Atmospheric pressure chemical vapor deposition (APCVD) of tungsten films using WF₆/H₂ chemistry has been studied. A statistical design of experiments approach and a surface response methodology were used to determine the most important process parameters and to obtain the best quality film possible in the parameter range studied. It was found that the deposition rate depends strongly on WF₆ flow rate, temperature, and the interaction between hydrogen flow rate and temperature. The resistivity was found to have a strong dependence on WF₆ and H₂ flow rates and temperature. An activation energy of 0.4 eV was calculated for the reaction rate limited growth regime. Empirical equations for predicting the deposition rate and resistivity were obtained. The resistivity decreases with both increasing film thickness and grain size. The films grown in the studied process parameter range indicate that (110) is the preferred orientation for films deposited with low WF₆/H₂ flow rate ratios at all deposition temperatures (350–450°C), whereas, the (222) orientation dominates at high WF₆/H₂ flow ratios and high deposition temperatures. Also, the grain size is larger for (222) oriented films than for (110) oriented films. The results of this study suggest that high-quality, thin film tungsten can be deposited using APCVD.     

TFEL optoelectronic integrated circuit on Si

A unique optoelectronic integrated circuit fabricated with AC thin film electroluminescent (TFEL) devices directly onto the drain of an Si DMOS transistor is demonstrated. DMOS switching controls the high voltage ratio between the TFEL device and DMOS transistor. Active matrix addressing for electroluminescent devices is demonstrated using CMOS circuitry     

混合集成电路金铝键合退化与控制研究动态

混合集成电路的两种金铝键合系统,有着不完全相同的两种退化模式。综述了相关的退化机理和控制方法的研究状况。金丝与芯片铝膜的Au/Al键合系统,是键合IMC、Kirkendall空洞导致其界面开裂失效;铝丝与厚膜金导体的Al/Au键合系统,除了界面开裂外,还存在键合根部因铝原子向IMC过度迁移而形成铝丝内部空洞导致铝丝断裂。采用铜丝代替金丝,可有效控制Au/Al键合系统的退化;采用过渡垫片或在金浆料中加入少量Pd,同时减少金导体膜厚度,可有效控制铝丝Al/Au键合系统的退化。     

Comment on `effect of external circuit on Gunn oscillation'

The authors comment on an article by T. Ikoma and H. Yanai, (see abstr. B4307 of 1968) which proposed a model for the quenched-dipole mode of operation of Gunn effect devices. They seek to correct errors related to current density equations. The authors of the first article reply.     

Mount-independent equivalent circuit of the S4 diode package

Broadband-admittance measurements have been made on dummy S4 diode packages mounted in a coaxial line. By comparing these with the theoretical admittance of a lumped-component equivalent circuit for the package and its mount similar to that of Getsinger, a consistent set of mount-independent equivalent-circuit parameters for the package has been derived.     

一种集成轨到轨比较器电路设计

传统比较器在其输入电压过高或过低时,输入MOS对管将进入截止区,从而使电路无法正常工作。本设计采用轨到轨放大器技术,使比较器在输入电压满摆幅时都能正常工作,增加了输入电压的范围。本文基于0.18μm COMS工艺完成电路的设计,并使用Spectre进行电路仿真。结果表明,在电源电压为1.8V时,电路静态功耗为360μW,电压比较精度为80μV,时延为13.2ns。     

Electromigration testing of integrated circuit interconnections

The electromigration phenomenon has been one of the most intriguing physical problems in the semiconductor device reliability. The models to explain the phenomenon are here revised, together with the influence of materials and their microstructure. The various measuring techniques are described, including the design of special test patterns, and statistical data analysis is briefly reviewed.     

Macromodeling of integrated circuit operational amplifiers

A macromodel has been developed for integrated circuit (IC) op amps which provides an excellent pin-for-pin representation. The model elements are those which are common to most circuit simulators. The macromodel is a factor of more than six times less complex than the original circuit, and provides simulated circuit responses that have run times which are an order of magnitude faster and less costly in comparison to modeling the op amp at the electronic device level. Expressions for the values of the elements of the macromodel are developed starting from values of typical response characteristics of the op amp. Examples are given for three representative op amps. In addition, the performance of the macromodel in linear and nonlinear systems is presented. For comparison, the simulated circuit performance when modeling at the device level is also demonstrated.     

集成电路芯片热机械应力特征研究

本文在试验和理论两个方面,系统研究了芯片热机械应力特征。作者利用红外热成像技术研究了芯片内部热机械应力随工作电流的瞬态变化关系,发现芯片热机械应力随工作电流呈对数增长。同时本文利用有限元方法模拟计算了芯片热机械应力在不同电流密度下与总工作电流的关系,从而验证了上述实验结论,并发现随着电流密度增加芯片内部热机械应力上升速率变快。     

基于FPGA的集成电路测试系统设计探讨

随着集成电路的功能以及各种参数的大量增加,要想保证电路的可靠性,就必须重视集成电路的测试功能,在传统的测试过程中,对集成电路的测试是依靠有经验的测试人员使用信号发生器、万用表和示波器等仪器来进行测试的.这种测试方法测试效率低,无法实现大规模大批量的测试.为此,本文分析了基于FPGA集成电路测试系统的优越性,并选取某集成电路的老化测试系统设计为例进行重点探讨.     

基于液态膜的集成电路电光检测技术

利用液态膜作为电场探测的电光材料。液态膜的探测电压灵敏度比Ga舡材料高2个数量级。其原理是,基于液态极性分子的取向极化,液态膜的折射率受电场调制,从而实现电光测量。实验结果表明,在调制电场1kHz频率下测量液态膜电光系数达到95pm／V。利用液态膜对集成电路进行检测具有简单、高效的特点,很好地完成了低频场探测中弱信号的...     

Increasing the bonding strength of chips on flex substrates using thermosonic flip-chip bonding process with nonconductive paste

Thermosonic flip-chip bonding process with a nonconductive paste (NCP) was employed to improve the processability and bonding strength of the flip-chip onto flex substrates (FCOF). A non-conductive paste was deposited on the surface of the copper electrodes over the flex substrate, and a chip with eight gold bumps bonded onto the copper electrodes by the thermosonic flip-chip bonding process.For the chips and flex substrates assembly, ultrasonic power is important in the removal of some of the non-conductive paste on the surface of copper electrodes during thermosonic bonding. Accordingly, gold stud bumps in this study were directly bonded onto copper electrodes to form successful electrical paths between chips and the flex substrate. A particular ultrasonic power resulted in some metallurgical bonding between the gold bumps and the copper electrodes, increasing the bonding strength. The ultrasonic power was not only to remove the NCP from the copper electrodes, but also formed metallurgical bonds during the thermosonic flip-chip bonding process with NCP.In this study, the parameters of the bonding of chips onto flex substrates using thermosonic flip-chip bonding process with NCP were a bonding force of 4.9 N, a curing time of 40 s, a curing temperature of 140 °C and an ultrasonic power of 14.46 W. The processability and bonding strength of flip-chips on flex substrates using thermosonic bonding process with NCP was verified in this study. This process has great potential to be applied to the packaging of consumed electronic products.     

大功率集成封装白光LED模组的散热研究

采用有限元分析软件ANSYS,分别对基于均温基板和金属芯印刷电路板结合太阳花散热器的100 W的大功率集成封装白光LED进行了热分析。结果发现:(1)相比金属芯印刷电路板,均温基板提高了LED芯片的均温性,可使每个LED芯片的温度分布一致,且每个芯片的最高温度比最低温度仅高1.1℃,避免了局部热点,从而提高了大功率集成封装白光LED的可靠性,保证了它的寿命。(2)太阳花散热器非常适合大功率集成封装白光LED模组的散热。因此对于大功率集成封装白光LED模组而言,均温基板结合太阳花散热器是一种有效的散热方式。