A Sample Preparation on Decapsulation Methodology for Effective Failure Analysis on Thin Small Leadless (TSLP) Flip Chip Package with Copper Pillar (CuP) Bump Interconnect Technology

Author(s):  
Gwee Hoon Yen ◽  
Ng Kiong Kay

Abstract Today, failure analysis involving flip chip [1] with copper pillar bump packaging technologies would be the major challenges faced by analysts. Most often, handling on the chips after destructive chemical decapsulation is extremely critical as there are several failure analysis steps to be continued such as chip level fault localization, chip micro probing for fault isolation, parallel lapping [2, 3, 4] and passive voltage contrast. Therefore, quality of sample preparation is critical. This paper discussed and demonstrated a quick, reliable and cost effective methodology to decapsulate the thin small leadless (TSLP) flip chip package with copper pillar (CuP) bump interconnect technology.

Author(s):  
Andrew J. Komrowski ◽  
N. S. Somcio ◽  
Daniel J. D. Sullivan ◽  
Charles R. Silvis ◽  
Luis Curiel ◽  
...  

Abstract The use of flip chip technology inside component packaging, so called flip chip in package (FCIP), is an increasingly common package type in the semiconductor industry because of high pin-counts, performance and reliability. Sample preparation methods and flows which enable physical failure analysis (PFA) of FCIP are thus in demand to characterize defects in die with these package types. As interconnect metallization schemes become more dense and complex, access to the backside silicon of a functional device also becomes important for fault isolation test purposes. To address these requirements, a detailed PFA flow is described which chronicles the sample preparation methods necessary to isolate a physical defect in the die of an organic-substrate FCIP.


Author(s):  
Lihong Cao ◽  
Manasa Venkata ◽  
Jeffery Huynh ◽  
Joseph Tan ◽  
Meng-Yeow Tay ◽  
...  

Abstract This paper describes the application of lock-in thermography (LIT) for flip-chip package-level failure analysis. LIT successfully detected and localized short failures related to both die/C4 bumps and package defects inside the organic substrate. The detail sample preparation to create short defects at different layers, LIT fault isolation methodology, and case studies performed with LIT are also presented in this paper.


Author(s):  
Michael B. Schmidt ◽  
Noor Jehan Saujauddin

Abstract Scan testing and passive voltage contrast (PVC) techniques have been widely used as failure analysis fault isolation tools. Scan diagnosis can narrow a failure to a given net and passive voltage contrast can give real-time, large-scale electronic information about a sample at various stages of deprocessing. In the highly competitive and challenging environment of today, failure analysis cycle time is very important. By combining scan FA with a much higher sensitivity passive voltage contrast technique, one can quickly find defects that have traditionally posed a great challenge.


Author(s):  
Sebastian Brand ◽  
Matthias Petzold ◽  
Peter Czurratis ◽  
Peter Hoffrogge

Abstract In industrial manufacturing of microelectronic components, non-destructive failure analysis methods are required for either quality control or for providing a rapid fault isolation and defect localization prior to detailed investigations requiring target preparation. Scanning acoustic microscopy (SAM) is a powerful tool enabling the inspection of internal structures in optically opaque materials non-destructively. In addition, depth specific information can be employed for two- and three-dimensional internal imaging without the need of time consuming tomographic scan procedures. The resolution achievable by acoustic microscopy is depending on parameters of both the test equipment and the sample under investigation. However, if applying acoustic microscopy for pure intensity imaging most of its potential remains unused. The aim of the current work was the development of a comprehensive analysis toolbox for extending the application of SAM by employing its full potential. Thus, typical case examples representing different fields of application were considered ranging from high density interconnect flip-chip devices over wafer-bonded components to solder tape connectors of a photovoltaic (PV) solar panel. The progress achieved during this work can be split into three categories: Signal Analysis and Parametric Imaging (SA-PI), Signal Analysis and Defect Evaluation (SA-DE) and Image Processing and Resolution Enhancement (IP-RE). Data acquisition was performed using a commercially available scanning acoustic microscope equipped with several ultrasonic transducers covering the frequency range from 15 MHz to 175 MHz. The acoustic data recorded were subjected to sophisticated algorithms operating in time-, frequency- and spatial domain for performing signal- and image analysis. In all three of the presented applications acoustic microscopy combined with signal- and image processing algorithms proved to be a powerful tool for non-destructive inspection.


Author(s):  
M.K. Dawood ◽  
C. Chen ◽  
P.K. Tan ◽  
S. James ◽  
P.S. Limin ◽  
...  

Abstract In this work, we present two case studies on the utilization of advanced nanoprobing on 20nm logic devices at contact layer to identify the root cause of scan logic failures. In both cases, conventional failure analysis followed by inspection of passive voltage contrast (PVC) failed to identify any abnormality in the devices. Technology advancement makes identifying failure mechanisms increasingly more challenging using conventional methods of physical failure analysis (PFA). Almost all PFA cases for 20nm technology node devices and beyond require Transmission Electron Microscopy (TEM) analysis. Before TEM analysis can be performed, fault isolation is required to correctly determine the precise failing location. Isolated transistor probing was performed on the suspected logic NMOS and PMOS transistors to identify the failing transistors for TEM analysis. In this paper, nanoprobing was used to isolate the failing transistor of a logic cell. Nanoprobing revealed anomalies between the drain and bulk junction which was found to be due to contact gouging of different severities.


Author(s):  
Julien Goxe ◽  
Béatrice Vanhuffel ◽  
Marie Castignolles ◽  
Thomas Zirilli

Abstract Passive Voltage Contrast (PVC) in a Scanning Electron Microscope (SEM) or a Focused Ion Beam (FIB) is a key Failure Analysis (FA) technique to highlight a leaky gate. The introduction of Silicon On Insulator (SOI) substrate in our recent automotive analog mixed-signal technology highlighted a new challenge: the Bottom Oxide (BOX) layer, by isolating the Silicon Active Area from the bulk made PVC technique less effective in finding leaky MOSFET gates. A solution involving sample preparation performed with standard FA toolset is proposed to enhance PVC on SOI substrate.


Author(s):  
Jason H. Lagar ◽  
Rudolf A. Sia

Abstract Most Wafer Level Chip Scale Package (WLCSP) units returned by customers for failure analysis are mounted on PCB modules with an epoxy underfill coating. The biggest challenge in failure analysis is the sample preparation to remove the WLCSP device from the PCB without inducing any mechanical defect. This includes the removal of the underfill material to enable further electrical verification and fault isolation analysis. This paper discusses the evaluations conducted in establishing the WLCSP demounting process and removal of the epoxy underfill coating. Combinations of different sample preparation techniques and physical failure analysis steps were evaluated. The established process enabled the electrical verification, fault isolation and further destructive analysis of WLCSP customer returns mounted on PCB and with an epoxy underfill coating material. This paper will also showcase some actual full failure analysis of WLCSP customer returns where the established process played a vital role in finding the failure mechanism.


Author(s):  
Swaminathan Subramanian ◽  
Khiem Ly ◽  
Tony Chrastecky

Abstract Visualization of dopant related anomalies in integrated circuits is extremely challenging. Cleaving of the die may not be possible in practical failure analysis situations that require extensive electrical fault isolation, where the failing die can be submitted of scanning probe microscopy analysis in various states such as partially depackaged die, backside thinned die, and so on. In advanced technologies, the circuit orientation in the wafer may not align with preferred crystallographic direction for cleaving the silicon or other substrates. In order to overcome these issues, a focused ion beam lift-out based approach for site-specific cross-section sample preparation is developed in this work. A directional mechanical polishing procedure to produce smooth damage-free surface for junction profiling is also implemented. Two failure analysis applications of the sample preparation method to visualize junction anomalies using scanning microwave microscopy are also discussed.


2015 ◽  
Vol 12 (3) ◽  
pp. 111-117
Author(s):  
Woon-Seong Kwon ◽  
Suresh Ramalingam ◽  
Xin Wu ◽  
Liam Madden ◽  
C. Y. Huang ◽  
...  

This article introduces the first comprehensive demonstration of new innovative technology comprising multiple key technologies for highly cost-effective and high-performance Xilinx field programmable gate array (FPGA), which is so-called stack silicon-less interconnect technology (SLIT) that provides the equivalent high-bandwidth connectivity and routing design-rule as stack silicon interconnect (SSI) technology at a cost-effective manner. We have successfully demonstrated the overall process integration and functions of our new SLIT-employed package using Virtex®-7 2000T FPGA product with chip-to-wafer stacking, wafer-level flux cleaning, microbump underfilling, mold encapsulation, and backside silicon removal. Of all technology elements, both full silicon removal process with faster etching and no dielectric layer damage and wafer warpage management after full silicon etching are most crucial elements to realize the SLIT technology. To manage the wafer warpage after full Si removal, a couple of knobs are identified and used such as top reinforcement layer, microbump underfill properties tuning, die thickness, die-to-die space, and total thickness adjustments. It is also discussed in the article how the wafer warpage behaves and how the wafer warpage is managed. New SLIT module shows excellent warpage characteristics of only −30 μm ∼ −40 μm at room temperature (25°C) for 25 mm × 31 mm in size and +20 μm ∼ +25 μm at reflow temperature (250°C). Thermal simulation results shows that thermal resistance of new SLIT package is almost comparable to that of standard 2000T flip-chip ball grid array (FC-BGA) package using through silicon via interposer with standard heat sink configuration and air wind condition. The reliability assessment is now under the study.


2021 ◽  
Author(s):  
Kuang-Tse Ho ◽  
Cheng-Che Li

Abstract This research summarizes failure analysis results about ionimplantation related issues in Si-based power devices, including diode, MOSFET and IGBT. To find out this kind of defects, sample preparation, fault isolation and SCM inspection are critical steps, which will be explained in detail in this paper.


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