THB Test Research Articles

High-Voltage Temperature Humidity Bias Test (HV-THB): Overview of Current Test Methodologies and Reliability Performances

The high voltage temperature humidity bias test (HV-THB) has become increasingly popular for evaluating the performances of power semiconductor devices. Given the new challenges of the power semiconductor industry, several applications and devices need to be designed to withstand harsh environments during working operations, with a remarkable focus on high-humidity conditions. The HV-THB test allows one to activate and study different failure mechanisms which were not highlighted by the standard low voltage THB test, enabling new designs in several energy conversion fields, such as energy harvesting, industry and automotive applications. After a brief introduction of current test standards, this work goes through the current methodologies and state-of-the-art of the HV-THB test. The following sections are then dedicated to the knowledge about the failure mechanisms and the models for accelerated testing. Eventually, there is a section devoted to the main passivation materials in order to understand their effects on the HV-THB capabilities of the devices.

Surface modification of thermoplastics by low-pressure microwave O2 plasma treatment for enhancement of the adhesion of the interface box/encapsulating resin and the influence on film capacitors operating under extreme humidity conditions

A low-pressure microwave O2 plasma is applied on the plastic boxes of the metallized film capacitors to strengthen the interfacial adhesion of thermoplastic box/encapsulating resin. The effectiveness of the plasma is reported by analyzing Scanning Electron Microscopy (SEM) micrographs, X-Ray Photoelectron Spectroscopy (XPS) spectra, and contact angle and roughness measurements. An enhancement of the polar character and total free surface energy in both thermoplastics (polybutylene terephthalate (PBT) and polycarbonate (PC)) are determined. Hence, a better wettability of the plastic boxes with the encapsulating epoxy resin is achieved after the plasma application. During the Temperature-Humidity Bias Test (THB), the metallized film capacitors with PC box improves the performance after being plasma treated. Additional capacitor interfaces seem to play a key role in the performance of the device according to the loss of capacitance determined during the THB Test.

Accuracy and Precision of the Pronto-7 for Noninvasive Hemoglobin Testing in An Outpatient Setting

Abstract 3147 IntroductionInvasive blood draw and laboratory analysis for determination of total hemoglobin concentration (tHb) is routine in the outpatient setting. However, the method is time consuming, uncomfortable for the patient, and exposes caregivers to risks associated with needle sticks and blood exposure. In contrast, hemoglobin determination with Pulse CO-Oximetry (SpHb) allows for noninvasive and quick estimation of hemoglobin with a spectrophotometric finger sensor. Continuous SpHb has been validated in the ICU [1], surgery[2], and volunteers undergoing hemodilution, [3] but the accuracy of “spot check” SpHb devices has not been validated in the outpatient setting. Our objective was to compare spot-check SpHb and invasive point-of-care (POC) hemoglobin testing to tHb measurements from a laboratory hematology analyzer. MethodsStudy subjects were adult and pediatric subjects presenting to two outpatient clinics and one health screening event. A noninvasive hemoglobin test device (Pronto-7, software version 2.19, Masimo Corp. Irvine CA) and reusable finger clip sensor (rainbow 4D) was placed on the patient's non-dominant ring finger. The sensor was covered with an opaque shield to prevent optical interference. Two consecutive SpHb readings were obtained from each subject, detaching and reattaching the sensor between each measurement. Testing was conducted while patients were quiet and sitting upright. A venous blood sample was obtained by venipuncture of the median cubital vein of the non-dominant arm and a capillary sample was obtained by finger stick according to the manufacturer's directions for use. The venous sample was analyzed for reference tHb with a laboratory hematology analyzer (LH 780, Beckman Coulter, USA). The capillary sample was analyzed immediately following the finger stick with a POC device (HemoCue 201+, Hemocue, Cypress CA). The SpHb and POC tHb were compared to the laboratory tHb. Bias, standard deviation, and coefficient of variation (precision) were calculated. ResultsA total of 474 subjects (37% male, 39 +/− 17 years of age) were enrolled, 431 (91%) from outpatient clinics and 43 (9%) from a community screening event. Subjects consisted of 246 (52%) healthy volunteers and 228 (48%) with one or more of the following conditions: high blood pressure, diabetes, high cholesterol, chronic obstructive pulmonary disease, or pregnancy. A total of 399 (84%) had light pigmentation, 71 (15%) medium pigmentation, and 3 (1%) had dark pigmentation. Reference tHb ranged from 8.6 to 17.4 g/dL. There were 877 SpHb measurements, 443 POC tHb measurements, and 473 reference tHb measurements. The mean bias and standard deviation of SpHb was −0.1 +/− 1.1 g/dL and of POC tHb was -0.1 and 1.6 g/dL. Using the first and second SpHb measurements, the precision of SpHb was 4.1%. ConclusionNoninvasive hemoglobin testing with the Pronto-7 had acceptable accuracy with similar bias and lower standard deviation than a widely available, POC tHB test device. The Pronto-7 has the potential to enhance patient care and caregiver safety in the outpatient setting. Disclosures:Shah:Masimo Corp.: Consultancy, Honoraria, Speakers Bureau. Martinez:Masimo Corp.: Research Funding. Osea:Masimo Corp.: Research Funding.

The Accuracy of Noninvasive and Continuous Total Hemoglobin Measurement by Pulse CO-Oximetry in Human Subjects Undergoing Hemodilution

Total hemoglobin (tHb) is one the most frequently ordered laboratory measurements. Pulse CO-Oximetry™ (Masimo Corp., Irvine, CA) is a multi-wavelength spectrophotometric method for noninvasive and continuous hemoglobin monitoring (SpHb). In this study, we evaluated the accuracy of SpHb compared with laboratory CO-Oximeter measurement of tHb from arterial blood samples in 20 healthy volunteer subjects undergoing hemodilution. After enrollment, approximately 500 mL of blood was drawn from subjects through an arterial or venous catheter. Each subject then rapidly received crystalloid i.v. fluid to compensate for the decrease in intravascular volume and reduce the hemoglobin concentration. Subjects received a maximum of 30 mL/kg i.v. fluid. SpHb was continuously monitored and recorded, and serial arterial blood samples were taken during the procedure. SpHb accuracy was analyzed by pairing SpHb and tHb measurements after the arterial blood draw with the resulting tHb test result. Bias, precision, and the average root-mean-square error were calculated. One hundred sixty-five tHb measurements were collected. The average decrease in tHb during the blood removal and hemodilution procedure was 2.4 ± 0.8 g/dL (mean ± SD). The average difference between 335 paired measurements of SpHb and tHb was -0.15 g/dL, 1 SD of the difference was 0.92 g/dL, and the average root-mean-square difference was 0.94 g/dL. The difference between SpHb and tHb was <2.0 g/dL for 97% of the measurements. The difference was <1.5 g/dL for 97% of the measurements when tHb was <10 g/dL. Pulse CO-Oximetry-based SpHb measurement is accurate within 1.0 g/dL (1 SD) compared with laboratory CO-Oximeter tHb measurement in subjects undergoing hemodilution.

AN EFFECTIVE PASSIVATION FILM STACK FOR THIN FILM BST CAPACITORS

ABSTRACT Thin film voltage tunable ferroelectric capacitors on various substrates are promising for use in high power microwave and other RF systems. Benefits of ferroelectric capacitors include miniaturization and integration with other passive devices. Commercialization of ferroelectric components requires compliance with certain industry standards for reliability. For ferroelectric capacitors the requirement to pass the THB test requires a silicon nitride layer in the back end of the process (after interconnect metalization). However the nitride layer deposition process results in a drastic increase in the leakage of the BST capacitors. This effect is attributed to the exposure of the ferroelectric material to atomic hydrogen which is a by-product of the PECVD deposition process. This paper presents results of different passivation materials for ferroelectric capacitors and for a barrier layer which preserves the performance of ferroelectric capacitors during a PECVD nitride deposition. This allows qualification of ferroelectric capacitors to industry reliability standards.

Observation of copper ionic migration in insulation layer by pulsed electroacoustic method [metal-base PWBs

We have studied the behavior of ionic impurities in the insulation layer of metal-base PWBs and carried out nondestructive detection of copper ionic migration using the pulsed electroacoustic method for measuring the space charge. Space charge polarization was observed initially and after pre-absorption under high-temperature, high-humidity conditions. It appears to be attributable to the ions present initially in the insulation layer. The space charge measurement detected a conductive region formed in the insulation layer near the anode after bias testing under high-temperature, high-humidity conditions (THB test). Element distribution analysis verified, it as a region of copper ionic migration. Growth of copper ionic migration in the insulation layer was detected nondestructively.

Searching for appropriate humidity accelerated migration reliability tests methods

Lifetime estimation is one of today's frequently used reliability testing tool. There are standardized test methods, mathematical apparatus and failure acceleration models for predicting failure rate of electronic components, circuit modules or equipment. Do the widespread used models give a precise description for all kind of failure mechanisms? Can they define the acceleration factor of any test, and the accelerated lifetime of any test vehicles? In connection with open surface migration tests (when the test circuit samples are not covered by any protective or packaging material) two climatic test methods (Thermal Humidity Bias––THB test methods with different parameter settings) have been compared: 40 °C/95%RH suggested by “a well known IEC standard” and 85 °C/85%RH required by the newer JEDEC standard. The novelty of the paper is the comparison between the two climatic test methods. The main conclusion is a suggestion to keep on with the old method in the mentioned particular case, which may be shocking for people who prefer the new standards. All conclusions are strengthened both with theoretical and experimental test results.

Direct current-voltage failure in lead magnesium niobate-based multilayer ceramic capacitors

Resistance measurement, P–E hysteresis measurement, and transmission electron microscope and energy dispersive analysis of x-rays (TEM-EDAX) analysis were used to study the resistance failure of lead magnesium niobate-based multilayer ceramic capacitors (MLCC) under dc voltage. It was found that the failure rate of MLCC with 1/9 Pd/Ag internal electrodes was 10 times that of MLCC with 3/7 Pd/Ag electrodes after the temperature–humidity–bias test (THB). Voltage shifts of hysteresis loops showed that an internal bias field between electrodes of MLCC was formed after THB test. Ag diffusion from electrodes into the ceramics during cofiring was examined through TEM-EDAX analysis. It was also found that the degraded specimens could be partially restored after storing under natural condition. On the basis of these results, the failure mechanism was established that oxygen vacancies induced by Ag diffusion accumulated under the external bias field, which increased the concentration of electronic defects, thereby resulting in the resistance failure of MLCC.

A new small CTE system from COPNA resin/E‐glass fabrics

Based on the superior properties of the COPNA resin laminate exhibiting Tg at 255∞C, small CTE at 5‐7 ppm (xy‐axis) and at 29 ppm (z‐axis), reliability of both two‐layered and six‐layered printed wiring boards using COPNA resin as a matrix were evaluated. In the case of the two‐layered system, it exhibited higher reliability than the FR‐4 graded epoxy‐resin laminate in the entire tests, and exhibited higher reliability than the BT resin laminate in the THB test, heat‐shock test, and heat‐cycle test. In the case of the six‐layered system, it also exhibited higher reliability than the BT system in both heat‐shock test and PC test.

Reliability evaluation of plastic packaged devices for long life applications by THB test

The reliability of transistors, bipolar and CMOS integrated circuits encapsulated in different types of plastic packages was investigated by using the 85°C/85% R.H. test with applied bias and the results compared with a long term operating life test. Particular attention was devoted to pointing out the influence of technology, process control and working conditions on device reliability and failure mechanisms. In micropackaged transistors the importance of surface passivation in protecting the devices against gold corrosion was forcused, while the need of good process control was confirmed by the results of the test on micropackaged linear integrated circuits. In dual-in-line CMOS integrated circuits silicon nitride and polymide give, in general, a superior protection, but good results were obtained also with normal P-glass passivation when a clever arrangement of layout design rules was adopted. Results obtained exhibit a significant improvement in the reliability of plastic packaged devices, with the best figures showing no failures after 15,000 hours at 85°C/85% R.H. test with bias.