Delta Resistance Measurement Impact On Thin (Metal) Film Resistors (original) (raw)
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Bimodal failure behaviour of metal film resistors
Quality and Reliability Engineering International, 1998
The ageing behaviour of metal film resistors was studied using high-resolution in-situ resistance measurements. A temperature storage experiment was performed at five different temperature levels. At each condition, the ageing behaviour of 128 resistors was monitored. It turned out that the failure behaviour of the samples is rather complicated. One remarkable fact is that measurements coming from two different production lots led to completely different results. One production lot displayed monomodal failure behaviour, while for the other lot bimodality was observed. Serious errors in the calculation of the FTTF (first time to failure) can be expected when this fact is not properly taken into consideration. This paper also discusses some important aspects of the analysis of failure time data, such as (i) the choice of the underlying failure distribution, (ii) the number of samples to be tested and (iii) the failure criterion to be used.
Pulse durability of thin-film resistors embedded in printed circuit boards
2011 International Students and Young Scientists Workshop "Photonics and Microsystems", 2011
The passives (resistors, capacitors, inductors) embedded in printed circuit boards (PCBs) can improve electrical properties and reliability of electronic systems. Pulse durability is an important parameter of passive components and active devices. In the case of resistors it allows to determine many properties including maximum power dissipation, resistance change or phenomena occurring in resistor structures after pulse surging. Furthermore pulse durability defines utility for pulse circuits. Thus this work presents pulse durability of thinfilm resistors made on the surface or embedded in Printed Circuit Boards. Investigated test structures were made of nickel-phosphorus (Ni-P) alloy on FR-4 laminate with sheet resistance 25 ȍ/sq or 100 ȍ/sq. Pulse durability was determined by calculating the maximum nondestructive electric field, maximum nondestructive surface power density or maximum nondestructive volume power density. These parameters were determined in dependence on pulse duration, resistor geometry (length, width, aspect ratio), type of cladding, laser trimming and accelerated aging process.
2018
Bulk metal foil and thin film resistors occasionally contain localized defects within the etched resistor pattern. Common defects of this type include in-line constrictions referred to as notches, unremoved resistor material bridges between adjacent pattern lines, and embedded non-conductive particles in the resistor material. Such defects are prone to fracture due to thermomechanical fatigue during powered operation, especially power cycling, resulting in positive resistance change and open circuit failure modes. Common screening methods of optical microscopy, short time overload power tests (e.g., 6.25x rated power for 5 seconds) and burn-in (e.g., 1.5x rated power for 100 hours) are useful, but they are not always effective at removing devices with such defects. An improved method has been developed to screen for localized resistor pattern defects. The method involves the application of brief, high power electrical pulses at a low duty cycle while inspecting the resistor with a h...
System Reliability, 2017
New contemporary applications of thick resistive films are inducing the need to investigate their behaviour under various stressing conditions. On the other hand, there is a growing interest in noise measurements as means of thick-film resistor quality and reliability evaluation and evaluation of degradation under stress. For these reasons, this chapter presents effects of mechanical, electrical and simultaneous mechanical and electrical straining on performances of conventional thick-film resistors that are analysed from micro-and macro-structural, charge transport and low-frequency noise aspects.
Environmental qualification testing and failure analysis of embedded resistors
IEEE Transactions on Advanced Packaging, 2005
Embedding passive components (capacitors, resistors, and inductors) within printed wiring boards (PWBs) is one of a series of technology advances enabling performance increases, size and weight reductions, and potentially economic advantages in electronic systems. This paper explores the reliability testing and subsequent failure analysis for laser-trimmed Gould subtractive nickel chromium and MacDermid additive nickel phosphorous embedded resistor technologies within a PWB. Laser-trimmed resistors that have been "reworked" using an inkjet printing process to add material to their surface to reduce resistance have also been considered. Environmental qualification testing performed included: thermal characterization, stabilization bake, temperature cycling, thermal shock and temperature/humidity aging. In addition, a pre/post-lamination analysis was performed to determine the effects of the board manufacturing process on the embedded resistors. A failure analysis consisting of optical inspection, scanning acoustic microscope (SAM) and environmental scanning electron microscope (ESEM) imaging, and PWB cross-sectioning was employed to determine failure mechanisms. All the embedded resistors were trimmed and the test samples included resistors fabricated both parallel and perpendicular to the weave of the board dielectric material. Material stability assessment and a comparison with discrete resistor technologies was performed.
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Microelectronics Reliability, 2018
This paper is focused on reliability tests of non-trimmed miniaturized thin-film and thick-film resistors. Thickfilm resistors are screen printed by polymer paste on LTCC (Low Temperature Co-fired Ceramic) substrate by two different approaches. Nonstandard precise screen printing process provide tolerance of resistivity less than 5% and thus further trimming is not necessary. OhmegaPly material with Nickel Phosphorous (NiP) metal alloy is used for thin-film resistors fabricated by subtractive process. Miniaturized resistors have dimensions 0.5 × 0.5 mm, and thus 1 square, with thickness 1 μm for thin-film and 20 μm for thick-film resistors. Stability of miniaturized resistors were tested by humidity test, thermal shocks, long-term thermal ageing, direct current stress, current pulses and simulation of soldering process using VPS (Vapour Phase Soldering). Resistivity of resistors is measured by four wire method before and after each set of test and relative change of resistivity is plotted in graphs. Influence of every test on each type of resistor is analysed.
Stability of thin-film resistors embedded in printed circuit boards
2011 International Students and Young Scientists Workshop "Photonics and Microsystems", 2011
Long-term stability of embedded passives is very important issue. To determine this matter an aging process can be used, where test samples are exposed to environmental conditions. Objecti ve of this research was analyzing reliability of thin-fil m resistors based on Ohmega-Ply® technol ogy. Resistive material was a nickelphosphorus (Ni-P) alloy (wi th sheet resistance 25 Ω/sq or 100 Ω/sq) on FR-4 substrate. A number of vari ables were considered in this study (sheet resistance, geometry of resistor, type of cl adding, l aser trimming, pulse stress and environmental conditi ons). Two di fferent accelerated ageing processes-Ex-Situ (samples exposed to elevated temperature and/or rel ati ve humi di ty but resistance measurements made at room temperature) and In-Situ (resistance of test samples performed directly at the ageing condi tions) were carried out to perform long-term behavior analysis. The results revealed a significant influence of thickness of resistor, type of cladding and temperature on stability of investigated structures. Signification of other factors was negligible.
Environmental tests of embedded thin- and thick-film resistors in comparison to chip resistors
Circuit World, 2014
In this work environmental behavior of resistors embedded into Printed Circuit Boards (PCBs) and discrete chip resistors assembled to standard PCBs are co mpared. The investigations were based on the thin-film resistors made of NiP alloy, thick-film resistors made of carbon or carbon-silver inks as well as chip resistors in 0402 and 0603 packages. Thin-and thickfilm resistors were made in the bar form. In addition, poly mer thick-film resistive films were screen-printed on the several types finishing materials of contact terminations such as copper, silver, and gold. To determine the sensitivity of embedded resistors versus s tandard assembled chip resistors on environmental exposure the climatic chamber was used. The measurements of resistance were carried out periodically during the tests, and after the exposure cycles.