Defect Isolation and Characterization in Contacts by Using Primary Voltage Adjustment

2003 ◽  
Author(s):  
Yuan-Shih Chen ◽  
Jeng-Han Lee
Keyword(s):  
Cmos Technology ◽  
Primary Energy ◽  
Site Isolation ◽  
Popular Method ◽  
Isolation And Characterization ◽  
Contrast Condition ◽  
Contrast Technique ◽  
Defect Isolation ◽  
Voltage Contrast ◽  
Failure Site

Abstract Voltage contrast(VC) is a popular method for failure site isolation[1]. After study we find some weakness on tradition voltage contrast. This paper presents a new voltage contrast procedure that can conquer the weakness. For a CMOS technology, there are four kinds of contact node were used. They are N+/PW node, P+/NW node , poly gate node and well node. Traditional voltage contrast condition uses constant SEM primary energy like 1KV can not distinguish these four kinds of node well. For example a contact lead to P+/NW will be bright in tradition VC[2], but a contact connected to well will also be bright. It means tradition VC can not distinguish difference between contact lead to P+/NW and contact lead to well. To improve the weakness of the traditional VC, we will present a new Voltage Contrast technique, which could distinguish all contact types in CMOS technology.

Application of Scan Based FA and Advanced Passive Voltage Contrast Technique in Defect Isolation

2003 ◽  
Author(s):  
Michael B. Schmidt ◽  
Noor Jehan Saujauddin
Keyword(s):  
Failure Analysis ◽  
Large Scale ◽  
Fault Isolation ◽  
Electronic Information ◽  
Scan Testing ◽  
Challenging Environment ◽  
Contrast Technique ◽  
Defect Isolation ◽  
Voltage Contrast ◽  
Higher Sensitivity

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.

Passive Voltage Contrast Technique for Rapid In-Line Characterization and Failure Isolation During Development of Deep-Submicron ASIC CMOS Technology

1998 ◽  
Author(s):  
Victor Liang ◽  
Harlan Sur ◽  
Subhas Bothra
Keyword(s):  
Gate Oxide ◽  
Cmos Technology ◽  
Relative Magnitude ◽  
Deep Submicron ◽  
Process Step ◽  
First Case ◽  
Contrast Technique ◽  
Rapid Characterization ◽  
Voltage Contrast

Abstract Three case studies in which the passive voltage contrast technique (PVC) was used in-fab during the development of a 0.25mm ASIC CMOS technology for rapid characterization and failure isolation are presented. The first case involved using the PVC technique to evaluate the gate oxide quality at different points of the process, allowing for quick identification of the process steps that were damaging the gate oxide and the relative magnitude of the damage that each process step contributed. PVC was then used to perform in-line evaluation of the split lots that were ran to address the problem without having to pull wafers off the line for electrical testing. In the second case study, PVC was used in-line to identify the source of siliciderelated gate-to-source/drain leakage. At this point of the process, electrical probing was not possible, and PVC circumvented this problem. The third case involved using PVC to help identify a new failure mechanism for tungsten plug vias that manifested itself due to plasma charging and layout peculiarities related to deep submicron design rules.

Method of Failure Site Isolation for Flash Memory Device Using FIB, Passive Voltage Contrast Techniques

2005 ◽  
Author(s):  
Caiwen Yuan ◽  
Susan Li ◽  
Andy Gray
Keyword(s):  
Flash Memory ◽  
Memory Device ◽  
Fault Isolation ◽  
Feature Size ◽  
Site Isolation ◽  
Physical Evidence ◽  
Small Feature ◽  
Voltage Contrast ◽  
Metal Layers ◽  
Failure Site

Abstract Current VLSI devices have very complicated circuit designs and very small feature size. As a result, fault isolation on failing devices becomes a more and more challenging task. Although backside photoemission technique is commonly used to detect the failure site covered with multiple metal layers, it has the disadvantages of more time consumption and less success rate. Without a localized failure site, it will be very difficult, sometime even impossible, to find the physical evidence for the failures. This article describes a method that has been successfully used for isolating the wordline leakage on a memory FLASH device using FIB cutting and passive voltage contrast on the leaky wordline. The concept of this article is not just limited to this application; rather it can be used for all similar types of fault isolation work for other applications.

Fault Isolation of MOL and FEOL Buried Defects Using Conductive Atomic Force Microscopy as a Complement to Passive Voltage Contrast Imaging

2017 ◽  
Author(s):  
Lucile C. Teague Sheridan ◽  
Linda Conohan ◽  
Chong Khiam Oh
Keyword(s):  
Atomic Force Microscopy ◽  
Cmos Technology ◽  
Fault Isolation ◽  
Contrast Imaging ◽  
Conductive Atomic Force Microscopy ◽  
Isolation Technique ◽  
Conductive Afm ◽  
Force Microscopy ◽  
Atomic Force ◽  
Voltage Contrast

Abstract Atomic force microscopy (AFM) methods have provided a wealth of knowledge into the topographic, electrical, mechanical, magnetic, and electrochemical properties of surfaces and materials at the micro- and nanoscale over the last several decades. More specifically, the application of conductive AFM (CAFM) techniques for failure analysis can provide a simultaneous view of the conductivity and topographic properties of the patterned features. As CMOS technology progresses to smaller and smaller devices, the benefits of CAFM techniques have become apparent [1-3]. Herein, we review several cases in which CAFM has been utilized as a fault-isolation technique to detect middle of line (MOL) and front end of line (FEOL) buried defects in 20nm technologies and beyond.

Fault Localization in Contact Level by Using Conductive Atomic Force Microscopy

2003 ◽  
Author(s):  
Jon C. Lee ◽  
J. H. Chuang
Keyword(s):  
Atomic Force Microscopy ◽  
Integrated Circuits ◽  
Fault Localization ◽  
Electrical Characterization ◽  
Conductive Atomic Force Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Optical Electron ◽  
Defect Isolation ◽  
Voltage Contrast

Abstract As integrated circuits (IC) have become more complicated with device features shrinking into the deep sub-micron range, so the challenge of defect isolation has become more difficult. Many failure analysis (FA) techniques using optical/electron beam and scanning probe microscopy (SPM) have been developed to improve the capability of defect isolation. SPM provides topographic imaging coupled with a variety of material characterization information such as thermal, magnetic, electric, capacitance, resistance and current with nano-meter scale resolution. Conductive atomic force microscopy (C-AFM) has been widely used for electrical characterization of dielectric film and gate oxide integrity (GOI). In this work, C-AFM has been successfully employed to isolate defects in the contact level and to discriminate various contact types. The current mapping of C-AFM has the potential to identify micro-leaky contacts better than voltage contrast (VC) imaging in SEM. It also provides I/V information that is helpful to diagnose the failure mechanism by comparing I/V curves of different contact types. C-AFM is able to localize faulty contacts with pico-amp current range and to characterize failure with nano-meter scale lateral resolution. C-AFM should become an important technique for IC fault localization. FA examples of this technique will be discussed in the article.

Investigations of Leakage Paths in Sub-0.35μm DRAM Products Using Advanced Focused Ion Beam Techniques

1998 ◽  
Author(s):  
H. Lorenz ◽  
C. Engel
Keyword(s):  
Focused Ion Beam ◽  
Cell Function ◽  
Dielectric Breakdown ◽  
Ion Beam ◽  
Electrical Characterization ◽  
Floating Gate ◽  
Leakage Path ◽  
Contrast Technique ◽  
Voltage Contrast

Abstract Due to the continuously decreasing cell size of DRAMs and concomitantly diminishing thickness of some insulating layers new failure mechanisms appear which until now had no significance for the cell function. For example high resistance leakage paths between closely spaced conductors can lead to retention problems. These are hard to detect by electrical characterization in a memory tester because the involved currents are in the range of pA. To analyze these failures we exploit the very sensitive passive voltage contrast of the Focused Ion Beam Microscope (FIB). The voltage contrast can further be enhanced by in-situ FIB preparations to obtain detailed information about the failure mechanism. The first part of this paper describes a method to detect a leakage path between a borderless contact on n-diffusion and an adjacent floating gate by passive voltage contrast achieved after FIB circuit modification. In the second part we will demonstrate the localization of a DRAM trench dielectric breakdown. In this case the FIB passive voltage contrast technique is not limited to the localization of the failing trench. We can also obtain the depth of the leakage path by selective insitu etching with XeF2 stopped immediately after a voltage contrast change.

The Application of FIB Voltage-Contrast Technique Combining with TEM on Subtle Defect Analysis: Via Delamination After TC

1997 ◽  
Author(s):  
X. Yang ◽  
X. Song
Keyword(s):  
Cross Section ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
New Product ◽  
Defect Analysis ◽  
Transmission Electron ◽  
Contrast Technique ◽  
Defect Mechanism ◽  
Open Defect ◽  
Voltage Contrast

Abstract Novel Focused Ion Beam (FIB) voltage-contrast technique combined with TEM has been used in this study to identify a certain subtle defect mechanism that caused reliability stress failures of a new product. The suspected defect was first isolated to a unique via along the row through electrical testing and layout analysis. Static voltage contrast of FIB cross-section was used to confirm the suspected open defect at the via. Precision Transmission Electron Microscope (TEM) was then used to reveal the detail of the defect. Based on the result, proper process changes were implemented. The failure mode was successfully eliminated and the reliability of the product was greatly improved.

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