A Technique for Reliably Preparing Full-Length Metallographic Cross-Sections of Integrated Circuit Bond Wires

Author(s):  
Carl Nail

Abstract To overcome the obstacles in preparing high-precision cross-sections of 'blind' bond wires in integrated circuits, this article proposes a different technique that generates reliable, repeatable cross-sections of bond wires across most or all of their lengths, allowing unencumbered and relatively artifact-free analysis of a given bond wire. The basic method for cross-sectioning a 'blind' bond wire involves radiographic analysis of the sample and metallographic preparation of the sample to the plane of interest. This is followed by tracking the exact location of the plane on the original radiograph using a stereomicroscope and finally darkfield imaging in which the wire is clearly visible with good resolution.

Author(s):  
Ann N. Campbell ◽  
William F. Filter ◽  
Nicholas Antoniou

Abstract Both the increased complexity of integrated circuits, resulting in six or more levels of integration, and the increasing use of flip-chip packaging have driven the development of integrated circuit (IC) failure analysis tools that can be applied to the backside of the chip. Among these new approaches are focused ion beam (FIB) tools and processes for performing chip edits/repairs from the die backside. This paper describes the use of backside FIB for a failure analysis application rather than for chip repair. Specifically, we used FIB technology to prepare an IC for inspection of voided metal interconnects (“lines”) and vias. Conventional FIB milling was combined with a superenhanced gas assisted milling process that uses XeF2 for rapid removal of large volumes of bulk silicon. This combined approach allowed removal of the TiW underlayer from a large number of M1 lines simultaneously, enabling rapid localization and plan view imaging of voids in lines and vias with backscattered electron (BSE) imaging in a scanning electron microscope (SEM). Sequential cross sections of individual voided vias enabled us to develop a 3D reconstruction of these voids. This information clarified how the voids were formed, helping us identify the IC process steps that needed to be changed.


Author(s):  
S. Khadpe ◽  
R. Faryniak

The Scanning Electron Microscope (SEM) is an important tool in Thick Film Hybrid Microcircuits Manufacturing because of its large depth of focus and three dimensional capability. This paper discusses some of the important areas in which the SEM is used to monitor process control and component failure modes during the various stages of manufacture of a typical hybrid microcircuit.Figure 1 shows a thick film hybrid microcircuit used in a Motorola Paging Receiver. The circuit consists of thick film resistors and conductors screened and fired on a ceramic (aluminum oxide) substrate. Two integrated circuit dice are bonded to the conductors by means of conductive epoxy and electrical connections from each integrated circuit to the substrate are made by ultrasonically bonding 1 mil aluminum wires from the die pads to appropriate conductor pads on the substrate. In addition to the integrated circuits and the resistors, the circuit includes seven chip capacitors soldered onto the substrate. Some of the important considerations involved in the selection and reliability aspects of the hybrid circuit components are: (a) the quality of the substrate; (b) the surface structure of the thick film conductors; (c) the metallization characteristics of the integrated circuit; and (d) the quality of the wire bond interconnections.


Author(s):  
N. David Theodore ◽  
Donald Y.C Lie ◽  
J. H. Song ◽  
Peter Crozier

SiGe is being extensively investigated for use in heterojunction bipolar-transistors (HBT) and high-speed integrated circuits. The material offers adjustable bandgaps, improved carrier mobilities over Si homostructures, and compatibility with Si-based integrated-circuit manufacturing. SiGe HBT performance can be improved by increasing the base-doping or by widening the base link-region by ion implantation. A problem that arises however is that implantation can enhance strain-relaxation of SiGe/Si.Furthermore, once misfit or threading dislocations result, the defects can give rise to recombination-generation in depletion regions of semiconductor devices. It is of relevance therefore to study the damage and anneal behavior of implanted SiGe layers. The present study investigates the microstructural behavior of phosphorus implanted pseudomorphic metastable Si0.88Ge0.12 films on silicon, exposed to various anneals.Metastable pseudomorphic Si0.88Ge0.12 films were grown ~265 nm thick on a silicon wafer by molecular-beam epitaxy. Pieces of this wafer were then implanted at room temperature with 100 keV phosphorus ions to a dose of 1.5×1015 cm-2.


1997 ◽  
Vol 473 ◽  
Author(s):  
David R. Clarke

ABSTRACTAs in other engineered structures, fracture occasionally occurs in integrated microelectronic circuits. Fracture can take a number of forms including voiding of metallic interconnect lines, decohesion of interfaces, and stress-induced microcracking of thin films. The characteristic feature that distinguishes such fracture phenomena from similar behaviors in other engineered structures is the length scales involved, typically micron and sub-micron. This length scale necessitates new techniques for measuring mechanical and fracture properties. In this work, we describe non-contact optical techniques for probing strains and a microscopic “decohesion” test for measuring interface fracture resistance in integrated circuits.


2000 ◽  
Vol 631 ◽  
Author(s):  
J. G. Fleming ◽  
E. Chow ◽  
S.-Y. Lin

ABSTRACTResonance Tunneling Diodes (RTDs) are devices that can demonstrate very highspeed operation. Typically they have been fabricated using epitaxial techniques and materials not consistent with standard commercial integrated circuits. We report here the first demonstration of SiO2-Si-SiO2 RTDs. These new structures were fabricated using novel combinations of silicon integrated circuit processes.


Author(s):  
Mark Kimball

Abstract This article presents a novel tool designed to allow circuit node measurements in a radio frequency (RF) integrated circuit. The discussion covers RF circuit problems; provides details on the Radio Probe design, which achieves an input impedance of 50Kohms and an overall attenuation factor of 0 dB; and describes signal to noise issues in the output signal, along with their improvement techniques. This cost-effective solution incorporates features that make it well suited to the task of differential measurement of circuit nodes within an RF IC. The Radio Probe concept offers a number of advantages compared to active probes. It is a single frequency measurement tool, so it complements, rather than replaces, active probes.


Author(s):  
Nicholas Randall ◽  
Rahul Premachandran Nair

Abstract With the growing complexity of integrated circuits (IC) comes the issue of quality control during the manufacturing process. In order to avoid late realization of design flaws which could be very expensive, the characterization of the mechanical properties of the IC components needs to be carried out in a more efficient and standardized manner. The effects of changes in the manufacturing process and materials used on the functioning and reliability of the final device also need to be addressed. Initial work on accurately determining several key mechanical properties of bonding pads, solder bumps and coatings using a combination of different methods and equipment has been summarized.


Author(s):  
Fenglei Du ◽  
Greg Bridges ◽  
D.J. Thomson ◽  
Rama R. Goruganthu ◽  
Shawn McBride ◽  
...  

Abstract With the ever-increasing density and performance of integrated circuits, non-invasive, accurate, and high spatial and temporal resolution electric signal measurement instruments hold the key to performing successful diagnostics and failure analysis. Sampled electrostatic force microscopy (EFM) has the potential for such applications. It provides a noninvasive approach to measuring high frequency internal integrated circuit signals. Previous EFMs operate using a repetitive single-pulse sampling approach and are inherently subject to the signal-to-noise ratio (SNR) problems when test pattern duty cycle times become large. In this paper we present an innovative technique that uses groups of pulses to improve the SNR of sampled EFM systems. The approach can easily provide more than an order-ofmagnitude improvement to the SNR. The details of the approach are presented.


Author(s):  
Halit Dogan ◽  
Md Mahbub Alam ◽  
Navid Asadizanjani ◽  
Sina Shahbazmohamadi ◽  
Domenic Forte ◽  
...  

Abstract X-ray tomography is a promising technique that can provide micron level, internal structure, and three dimensional (3D) information of an integrated circuit (IC) component without the need for serial sectioning or decapsulation. This is especially useful for counterfeit IC detection as demonstrated by recent work. Although the components remain physically intact during tomography, the effect of radiation on the electrical functionality is not yet fully investigated. In this paper we analyze the impact of X-ray tomography on the reliability of ICs with different fabrication technologies. We perform a 3D imaging using an advanced X-ray machine on Intel flash memories, Macronix flash memories, Xilinx Spartan 3 and Spartan 6 FPGAs. Electrical functionalities are then tested in a systematic procedure after each round of tomography to estimate the impact of X-ray on Flash erase time, read margin, and program operation, and the frequencies of ring oscillators in the FPGAs. A major finding is that erase times for flash memories of older technology are significantly degraded when exposed to tomography, eventually resulting in failure. However, the flash and Xilinx FPGAs of newer technologies seem less sensitive to tomography, as only minor degradations are observed. Further, we did not identify permanent failures for any chips in the time needed to perform tomography for counterfeit detection (approximately 2 hours).


Author(s):  
Alexander Sorkin ◽  
Chris Pawlowicz ◽  
Alex Krechmer ◽  
Michael W. Phaneuf

Abstract Competitive circuit analysis of Integrated Circuits (ICs) is one of the most challenging types of analysis. It involves multiple complex IC die de-processing/de-layering steps while keeping precise planarity from metal layer to metal layer. Each step is followed by Scanning Electron Microscope (SEM) imaging together with mosaicking that subsequently passes through an image recognition and Graphic Database System (GDS) conversion process. This conventional procedure is quite time and resource consuming. The current paper discusses and demonstrates a new inventive methodology of circuit tracing on an IC using known FIB Passive Voltage Contrast (PVC) effects [1]. This technique provides significant savings in time and resources.


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