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Journal Articles
EDFA Technical Articles (2015) 17 (4): 14–20.
Published: 01 November 2015
.... They describe each step of the analog circuit editing process, explaining how they deposit, characterize, and connect matched resistors using focused ion beam techniques. During a silicon debug, it was found that the gain of a radio receiver circuit dropped dramatically at certain frequencies due...
Journal Articles
EDFA Technical Articles (2007) 9 (4): 22–25.
Published: 01 November 2007
...John Barden; Joel Harrison Nanoprobing of transistors and resistors is increasing in importance for both design debug and electrical fault isolation. It is thus necessary to understand the impact of scanning a resistor or transistor with an electron beam in order to draw valid conclusions from...
Journal Articles
EDFA Technical Articles (2018) 20 (3): 24–33.
Published: 01 August 2018
... of this article show how such challenges can be overcome using EBIC/EBAC, current imaging, and nanoprobing. The cases involve a wide range of issues, including resistor chain defects, substrate leakage, microcracking, micro contamination, and open failures due to copper plating problems and missing vias...
Journal Articles
EDFA Technical Articles (2020) 22 (4): 20–25.
Published: 01 November 2020
... in ceramic chip capacitors and resistors, voids in a full-bridge rectifier, and a radiation-induced defect in a microprocessor. In cases involving counterfeit ICs, CSAM images reveal the presence of an abnormality on component packages, evidence of relabeling, and popcorn fractures indicative of the use...
Journal Articles
EDFA Technical Articles (1999) 1 (3): 21–24.
Published: 01 August 1999
...John R. Devaney Scanning electron microscopes can be used to analyze almost anything that conducts electricity and is prone to failure, including relays, coils, inductors, capacitors, resistors, transistors, diodes, IGBTS, MOSFETS, and hybrid circuits. As the author of the article explains, SEMs...
Journal Articles
EDFA Technical Articles (2001) 3 (4): 37–39.
Published: 01 November 2001
...-mount resistors had shorted, is attributed to silver’s susceptibility to electrolytic migration. Copyright © ASM International® 2001 2001 ASM International electrolytic migration potentiometers relays resistors silver sulfur tarnish httpsdoi.org/10.31399/asm.edfa.2001-4.p037 EDFAAO...
Journal Articles
EDFA Technical Articles (1999) 1 (3): 1–28.
Published: 01 August 1999
...-signals, continued n+ buried layer, which is implanted in the nwell and extends outside the p+ region connected to a collector. An example of a PNP transistor used in an input protection structure is shown in (Fig. 1). Passive analog components onchip include inductors, resistors, and capacitors...
Journal Articles
EDFA Technical Articles (2019) 21 (4): 22–28.
Published: 01 November 2019
... system (GIS)-assisted FIB induced deposition of a pull-up resistor between two networks. The second use case is an investigation of the localization of a short between two metal layers using EBAC and FIB metal line cutting. EQUIPMENT A FIB-SEM microscope equipped with a GIS from Carl Zeiss AG was used...
Journal Articles
EDFA Technical Articles (1999) 1 (4): 4–26.
Published: 01 November 1999
... polysilicon resistor. In this case, the NMOS transistor has neither source nor drain tied to a supply, but its bulk is tied to ground. This failure analysis was initiated by a field return from a camcorder manufacturer. The failure symptom was highleakage current on an analog input pin called MIDDVDD...
Journal Articles
EDFA Technical Articles (2019) 21 (1): 26–31.
Published: 01 February 2019
... is hazardous and could destroy switching transistors or cause input fuses to burn out. This hazardous parasitic LC ringing cannot be eliminated, but it can be damped by the series resistors, which include the PWM/driver output impedance Rdri, external gate resistor RG in the drive circuit such as R1 in Fig. 1a...
Journal Articles
EDFA Technical Articles (2021) 23 (3): 13–22.
Published: 01 August 2021
... circuits or resistor values. Conversely, with access to a complete set of Gerber files, it is not terribly difficult for an experienced designer to figure out the basics of a circuit board. For example, most designs have a single processor or microcontroller which is a strikingly large component...
Journal Articles
EDFA Technical Articles (2005) 7 (2): 14–19.
Published: 01 May 2005
... random access memory (DRAM) cell arrays as well as in logic circuits.[1] A weak open in the path between cell capacitor, C, and bitline connected to VBL, for example, an additional resistor due to a missing implantation, is depicted in Fig. 1. This failure mode is called a single-cell failure...
Journal Articles
EDFA Technical Articles (2004) 6 (2): 6–11.
Published: 01 May 2004
... trimming of resistors in analog circuits, capacitance tuning in matching circuits, trimming of microstrips or termination stubs in high-frequency circuit applications, enabling or disabling of fuse links in memory chips to invoke redundant memory elements, and so on. Laser trimming is often used...
Journal Articles
EDFA Technical Articles (2005) 7 (3): 22–28.
Published: 01 August 2005
... voltage range over which the I-V curve is obtained reduces the controllability and observability of LYA as a DFT technique. This Fig. 2 Typical 6T-SRAM cell with potential defects modeled as resistors will further degrade as the size of the cache increases, as more cores are introduced, and as the level...
Journal Articles
EDFA Technical Articles (2003) 5 (3): 23–28.
Published: 01 August 2003
... the relative transistor sizes (x) or any mismatch in the resistors (R1/R2) will adversely affect the operation of the voltage reference. There are methods to trim component values built into the circuit. Some of the possible failure modes and mechanisms for voltage regulators are shown in Table 1. High Speed...
Journal Articles
EDFA Technical Articles (2000) 2 (1): 17–19.
Published: 01 February 2000
... of <lmA was observed). Nevenhcless, under dynamic bias, lee dramatically increased to several rnA, and the I-V characteristic F~ 1: Under~bias, Icc was a few rnA and the I-V CU\'e extW;rits a hyst&es:is loop; the left top oomershows the Icc CtMW of a good device (or when the failed device was .il:.minated). ELECTRONIC DEVICE FAILURE ANALYSIS NEWS I .. Fig. 2: Emission site detected at the NMOS transistor of Vcc clamp (emission site coincided with the whole width of the transistor). From experience. emission from a s.1111ratt'd lr.lI1siSlor Vee docs not necessarily indicate it is defective. II is lhcrcforc illlportantto critically re· view the results before cm· bmking on destruclive deproccssmg. with Ihe inlent ofdctcnnining the probabk causes and to increase Ihe success role. ; roC Qn:: \t: R 1-- '- FIg. 3: The SChematIC of The Vee clamp. as shown Vee in Figure 3, is basically a Gate·Couplcd MOS (GC- NMOS) ESD prolccl1on circuit Ifa very fast transient, an ESD pulse for instance. were 10 hil the Vee nIXie, it would (Conlllllied QlI next page) 17 Case History, C'fJ/llillll('d transmit to the gMe of the NMOS v. ith lillie anenuation because the capacitor h:IS negligible impedance at that frequency, The resulting increase ill the gate voltage mstallt.1/1cously triggers the NMOS tmnsbtor into snapback. thus providing a rapid discharge. At lov,.er frequency. the impedance of the C3p0Citor is rather large. thus blocking the signal to the gate. l1lc MOS transistor is not c.'I(pected to be triggered at oo-ice operating frequency or dunng testmg. The fact !hat the MOS tr.Ulsistor is Ul S:ltUJ:ltion mode may indicate the causes to be the NMOS transistor is defcetivedam3Cd: the gate resistor IS open. for example. due to an open via: or other defects. The fi~ possibtllty is rcmotcorcbc thedcicc QUid havc failed at statK: bl3S. For the second hypothesis.. the best way to test it is to simulate the failure. By using FIB milling. the gatc resistor of a b'OOO oo'icc is di:.ronnccted. Subsequent \'criflCation sho\\ S that the modified device indeed C'l(hlblts the same failure mode and. more imponamly. a SImilar photon emission site is detected. This reinforces the validity ofthe hypothesis. The circuIt analysIS and simul1tion has gi\'Cfl \'3luab1c clues Fig. 4: A strip of foreign material at BPSG and metal 1 levels traversing the gate resistor. as to what we should be looking for: for example. something that may cause the g.1te resistor to be open. The next step is to do.1JfOCCSS the device sequentially and inspect for a defect No physical defect was observed at the top and metal 2 levels, 110\\ ever. at me!:ll I and BPSG levels. a long strip of material was obscr\.ed at the Vce clamp. traversing the g.1te resistor (Fig, 4). Mechanical problllg across the resistor funher conlinncd that It was open circuited. \\hilea resiSlallCe of30 kf! was obtained for a ~'OOd device (Fig. 5). In addition. by varying the intensity ofthe illummation incident on the die. the I-V characteristic l'CSnbkd thaI of a phoco-diodc (Fig. 6). Underslanding the Failure \lechanism "The failure is 00\ iously due to a fabrication defect. "The strip of rnalerial is prob..1bly an ctchmg residue during patterning of metal I DespIte finding the root cause of this Icc failure. the faIlure mcchamSlll rcmallled not fully understood. There is some peculiar bchavlor to be addressed. For instance. \\ hy is the defective device able to pass static lec test \\ hen It falls the S3JTIC test:lt dynamic bias? And v,.hy is the faIlure sensitive to Illumination (failed \\ hen dark. but passed \\ hen Illuminated)? Let us e'l(almne the GCNMOS Vce clamp in detail. and how It behavcs under static and dynamic conditions. EssentIally. the GCNMOS is similar to an NMOS output transistor cxecpl that the gate is Iied to Vss through a large N·wdl resistor.~ TIle NMOS transistor functions as a npn SCR and is triggen.'d by the gate voltage. The brcak-over voltage (dmin voltage) of the SCR is lowered when the gate voltage is raised. The capacitor serves as a low impedance fXlth for a fast tmnsielll (for example. ESD), but otherwise is:m open circuit to d,e, or low frequency fluctuation at the Vcc node. In the event of an ESD (spike) at the Vee node. a large ClllTl.'lt will momentarily fXlS through the RC network and mise the gate potcntial. This will instantancously trigger the NMOS tmnsistor into snapback. thus discharging the spike through the substratc. After the spike is fully discharged. tile NMOS tmnsistor will revert to its offstate. At device operating frequency, the impedance of tile capacitor C;s so large tl13t tllCfC is insulfK:ient CWTCllt Fig. 5: Probing across the gate resistor showed that it - is- open; a good device has resistance or 30 leW Fig. 6: The defective resistor behaves like a photo-diode. c= 18 ELECfRONIC DErICE FAILURE ANALYSIS NEWS to initiate snapb.1ek. TIle purpose ofthe resistor R is to tic the gate of NMOS to Vss under nonnal operating frequency. Next consider a faulty clamp with the resistor open circuited. 111is time, the gate ofthe NMOS is flooting except for the IXlmsitic vertical diode from the N-well resistor (Fig. 7). The parasitic diode actually acts as a photo-diode as shown by mechanical probing. This mcans that undcr ambient illumination. the pamsitic diode now acts as a discharge path by ]Xl'>Sing the open resistor. 111e gate potential is at nearly zero volt w.r.1. Vss, thus the NMOS will not tum 011, and the device will pass both the static and dynamic lec tcsts. On the other hand, at dark ambient, the parasitic diode is cssentiallyan open circuit. 111e gate of NMOS is now at a flo..1ting...
Journal Articles
EDFA Technical Articles (2014) 16 (2): 18–23.
Published: 01 May 2014
.... Prymak: Tantalum Capacitors in Power Supply Applications, PCIM Conference Japan, PCIM and Interec International, Inc., 1998. 4. J. Prymak: Replacing MnO2 with Conductive Polymer in Tantalum Capacitors, Capacitors and Resistors Technology Symposium Europe, Electronic Components Institute...
Journal Articles
EDFA Technical Articles (2013) 15 (2): 32–39.
Published: 01 May 2013
... may appear out of place, such as a darkened area on a board or connector or a color change on a component such as a resistor/capacitor. The authors had a sputter coater that stopped working. Upon inspection of a main circuit board, it was noticed that one of the high-power resistors did not match...
Journal Articles
EDFA Technical Articles (2017) 19 (4): 22–34.
Published: 01 November 2017
...) presents a negative sensitivity to thermal stimulus. Soft defect localization (SDL) is chosen to isolate the critical circuitries. Figure 11(a) shows the SDL signal overlay image. Five signal spots were obtained, and a layout analysis found them to be related to some contacts of poly resistor chains (Fig...
Journal Articles
EDFA Technical Articles (2006) 8 (1): 6–14.
Published: 01 February 2006
... with a high level. The timing of this write operation is critical and is displayed in Fig. 1. The graph shows the voltage levels on the true and complement bitlines and the voltage levels of a good cell and a cell with a faulty resistor. All voltage levels Fig. 1 Diagram of write timing. Voltages for true...