scholarly journals Failure Analysis of a Half-Micron CMOS IC Technology

Author(s):  
A.Y. Liang ◽  
P. Tangyunyong ◽  
R.S. Bennett ◽  
R.S. Flores ◽  
J.M. Soden ◽  
...  

Abstract We present the results of recent failure analysis of an advanced, 0.5 um, fully planarized, triple metallization CMOS technology. A variety of failure analysis (FA) tools and techniques were used to localize and identify defects generated by wafer processing. These include light (photon) emission microscopy (LE), fluorescent microthermal imaging (FMI), focused ion beam cross sectioning, SEM/voltage contrast imaging, resistive contrast imaging (RCI), and e-beam testing using an IDS-5000 with an HP 82000. The defects identified included inter- and intra-metal shorts, gate oxide shorts due to plasma processing damage, and high contact resistance due to the contact etch and deposition process. Root causes of these defects were determined and corrective action was taken to improve yield and reliability.

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):  
Fritz Christian Awitan ◽  
Camille Joyce Garcia ◽  
Dirk Andrew Doyle ◽  
Lawrence Benedict

Abstract An ARC solution that can be used to improve backside imaging for backside photoemission microscopy applications is presented in this paper. Zinc Oxide (ZnO) -based thin films used as ARCs are deposited at the backside of the failing units through a simple and low cost spray pyrolysis technique. An improvised set-up, composed of an atomizer and a hot plate, is used in the experiment. The paper provides evidence of acceptable process repeatability and demonstrates that the technique and the material have important applications in the field of failure analysis. Furthermore, it shows that the application of ARC resulted in better defect localization. The location of the defect is easily been determined upon doing frontside inspection - to - backside image comparison on the deposited unit. By using high kV ion beam passive voltage contrast (PVC) and angled cut focused ion beam (FIB) cross section, we are able to isolate further and show the nature of the defect at the failing block.


Author(s):  
Jim Shearer ◽  
Kim Le ◽  
Xiaoyu Yang ◽  
Monty Cleeves ◽  
Al Meeks

Abstract This article presents a case study to solve an IDDQ leakage problem using a variety of failure analysis techniques on a product. The product is fabricated using a 3-metal-layer 0.25 μm CMOS process with the addition of Matrix's proprietary 3-D memory layers. The failure analysis used both top and backside analytical techniques, including liquid crystal, photon emission microscopy from both front and back, dual-beam focused ion beam cross-sectioning, field emission scanning electron microscopy imaging, parallel-lap/passive voltage contrast, microprobing of parallel-lapped samples, and scanning capacitance microscopy. The article discusses how the application of each of the techniques narrowed down the search for this IDDQ leakage path. This leakage path was eliminated using the two corrective actions: The resist is pre-treated prior to ion implantation to produce a consistent resist sidewall profile; and the Nwell boundaries were adjusted in the next Nwell mask revision.


Author(s):  
S.L. Ting ◽  
P.K. Tan ◽  
I. Withana ◽  
H. Tan ◽  
C.Q. Chen

Abstract Passive voltage contrast (PVC) is widely used to detect underlying connectivity issues between metals based on the brightness of upper metals using scanning electron microscopy (SEM) or focused ion beam (FIB). [1] However, it cannot be applied in all cases due to the uniqueness of each case where brightness alone is insufficient to tell leakage location. In this study, propose a simple technique using platinum (Pt) marking as a circuit edit (CE) technique to alter metal PVC to identify the actual leakage location. Conventional SEM and PVC contrast imaging are unable to pinpoint exact defects without data confirming the leakage from nano-probing such as Atomic Force Probing (AFP) or SEM base nano-probing (NP) [2]. Using this method, we can improve the analysis cycle time by direct analysts the defective location in SEM, while also saving tool cost.


Author(s):  
D. Luo ◽  
X. Song

Abstract A single bit failure is the most common and the most difficult failure mode to analyze in a Static Random Access Memory (SRAM). As chip feature sizes decrease, the difficulties compound. Traditional failure analysis techniques are often ineffective, particularly for high temperature operating life (HTOL) failures, because HTOL failures are most often caused by subtle physical defects. A new analysis approach, using Focused Ion Beam (FIB) cross-sectioning combined with Fffi passive voltage contrast (PVC), greatly enhances the analysis success rate. In this paper, we outline the use of these new techniques and apply them to a technologically important problem.


Author(s):  
G. Benstetter ◽  
G. Bomberger ◽  
P. Coutu ◽  
R. Danyew ◽  
R. Douse

Abstract Reducing the cell size of DRAMs in 0.35 micron and follow-on technologies requires failure analysis techniques that can analyze single storage node trench capacitors on both test sites and actual product. A combination of electrical microprobing, probeless voltage contrast and physical delayering procedures, all based on focused- ion-beam (FIB) techniques, are described. Because of precise fail localization, high resolution scanning electron microscope (SEM) imaging enables the distinction between process defects and intrinsic breakdowns of node dielectric defects. Isolated storage cells can be electrically characterized by depositing small probe pads, using FIB for contact hole milling and probe-pad deposition. To localize trench capacitors with a leakage path to the surrounding substrate, the trenches are isolated by mechanical polishing and probeless voltage contrast in the FIB tool. Failing trench capacitors can be marked in the FIB tool. Physical isolation of leaking trench capacitors can be achieved by recessing the adjacent trench capacitors, with the FIB used for milling and a subsequent wet chemical removal added for the remaining substrate material. Alternatively, trench capacitors can be inspected from the backside when stabilized by a quartz deposition on top, followed by mechanical polishing from the side and a wet chemical etching of the remaining substrate material. In both cases, the dielectric of the node trench capacitors can be inspected by high resolution SEMs and the defect areas precisely analyzed.


1998 ◽  
Vol 523 ◽  
Author(s):  
Larry Rice ◽  
Wei Chen

AbstractAs ULSI device critical dimensions continue to shrink to submicron sizes, electron microscopy techniques such as electron beam induced current (EBIC) and voltage contrast are finding more applications towards pinpointing failure sites for subsequent cross sectioning or deprocessing. In addition to the traditional use of EBIC for junction delineation, EBIC has been applied to locate leakage sites in capacitor structures and silicon-on-insulator (SOI) devices as well. Similarly, voltage contrast has been applied to identify single or multiple opens in via chains which consist of thousands of vias. In addition to a brief revisit of the basic principles of EBIC and voltage contrast, focus will be placed on the application of EBIC and voltage contrast in failure analysis of semiconductor devices. Examples of using voltage contrast combined with precision cross section focused ion beam (XFIB) for identifying the failure mechanism of 0.8μm vias will be presented. Also, the use of EBIC for identifying leakage sites in SOI and bipolar devices and subsequent FIB/scanning electron microscopy (SEM) analysis will be presented.


Author(s):  
Lucile C. Teague Sheridan ◽  
Linda Conohan ◽  
Chong Khiam Oh

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.


Author(s):  
Natsuko Asano ◽  
Shunsuke Asahina ◽  
Natasha Erdman

Abstract Voltage contrast (VC) observation using a scanning electron microscope (SEM) or a focused ion beam (FIB) is a common failure analysis technique for semiconductor devices.[1] The VC information allows understanding of failure localization issues. In general, VC images are acquired using secondary electrons (SEs) from a sample surface at an acceleration voltage of 0.8–2.0 kV in SEM. In this study, we aimed to find an optimized electron energy range for VC acquisition using Auger electron spectroscopy (AES) for quantitative understanding.


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