Moisture Uptake of Bisbenzocyclobutene (BCB) Films for Electronic Packaging Applications

1990 ◽  
Vol 203 ◽  
Author(s):  
Hartono Pranjoto ◽  
Denice D. Denton
Keyword(s):  
Relative Humidity ◽  
Integrated Circuit ◽  
Electronic Packaging ◽  
Moisture Absorption ◽  
Dielectric Material ◽  
Transient Behavior ◽  
Equilibration Time ◽  
Moisture Uptake ◽  
Ambient Relative Humidity ◽  
Conflicting Demands

ABSTRACTElectronic packaging has been changing.rapidly to meet the often conflicting demands of higher speed and lower cost. In the multichip module (MCM), an array of semiconductor chips is mounted on a substrate and interconnected via a network of multilevel metal lines with polymer layers used as a dielectric between orthogonal metal signal paths. A potential reliability problem that must be investigated is the absorption of moisture by the dielectric in the MCM package. Moisture absorption may lead to long term problems such as loss of adhesion, corrosion of the metal interconnect and increased insulator conductivity.Bisbenzocyclobutene (BCB) is an insulating polymer that is being used in the MCM package as a dielectric material. In this work, the moisture uptake in BCB is investigated gravimetrically using a Cahn-1000 microbalance with a resolution of I pgram. The BCB films are spincoated onto silicon substrates and cured yielding film thickness ranging from 7 to 20µm. The moisture uptake of the BCB film is monitored in situ and non destructively to reveal the performance of the film as used in an integrated circuit environment. The moisture uptake of the films was monitored at different ambient relative humidity (RIH) values between 20% and 80% at 23°C. The transient behavior of the moisture absorption in BCB films has been characterized. Moisture uptake in BCB films increases as the relative humidity is increased, and reaches a maximum of less than 0.2% by weight at 80% RH. By comparison, this moisture uptake is significantly lower than that of fully cured PMDA-ODA polyimide, which is about 2.5% by weight under similar conditions. The transient data show that the equilibration time for a 22.8 µ.m film is approximately 220 seconds, yielding a diffusion coefficient of about 4.5µm2/s.

Effect Of Moisture On The Physical Properties Of Polyimide Films

1991 ◽  
Vol 227 ◽  
Author(s):  
Rajeevi Subramanian ◽  
Michael T. Pottiger ◽  
Jacqueline H. Morris ◽  
Joseph P. Curilla
Keyword(s):  
Dielectric Constant ◽  
Steady State ◽  
Electrical Properties ◽  
Relative Humidity ◽  
Quartz Crystal ◽  
Moisture Absorption ◽  
Relative Dielectric Constant ◽  
Moisture Uptake ◽  
Polyimide Films ◽  
Effect Of Moisture

ABSTRACTMoisture absorption and its effect on electrical properties were measured for several polyimides. A Quartz Crystal Microbalance (QCM) was used to investigate the moisture absorption in BPDA/PPD, PMDA/ODA, and BTDA//ODA/MPD polyimides. The steady-state moisture uptake in polyimides as a function of relative humidity (RH) was determined by exposing film samples to successively higher RH values ranging from 10 to 85% at 25°C. The isothermal moisture absorption as a function of percent RH was found to be nearly linear for all of the polyimides studied. The effect of moisture on the electrical properties of a BPDA/PPD polyimide was also investigated. The relative dielectric constant at 25 °C was found to be a linear function of the moisture absorbed.

Performance of Desiccant Solar Crop Dryers in Makurdi, Nigeria

2019 ◽  
Vol 35 (2) ◽  
pp. 259-270 ◽  
Author(s):  
Isaac N Itodo ◽  
Joshua O Ijabo ◽  
Japheth A Charles ◽  
Nathaniel N Ezeanaka ◽  
Solomon O Akpa
Keyword(s):  
Relative Humidity ◽  
Moisture Absorption ◽  
Drying Rate ◽  
Sun Drying ◽  
Ambient Relative Humidity ◽  
Significant Difference ◽  
Drying Rates ◽  
Fan Speed ◽  
Further Development ◽  
Range Test

Abstract. Dryers in humid tropical locations like Makurdi, Nigeria (Lat. 7°7´N), have not performed significantly better than the open air sun drying of crops because of the high ambient relative humidity that is often not less than 70% all year round, hence the need to use desiccant augmented dryers. The performance of three types of non-regenerative desiccant solar crop dryers was undertaken to determine the best performing dryer configuration for further improvement and use in the location. The dryers developed were the indirect-active desiccant dryer (IADD), direct-active desiccant dryer (DADD), and the direct-passive desiccant dryer (DPDD). The dryers were designed, constructed, and their performance evaluated and compared to open air sun drying (OASD). The drying rate (kg/h) and Dryer Performance Coefficient (DPC) were used to evaluate the performance of the dryers. The active dryers were operated at a fan speed of 1.2 m/s. Moisture absorption rate and % moisture absorbed to its weight were used to evaluate the performance of the desiccant. The desiccant used was a composite of rice husk ash (RHA) and calcium chloride binded with cement in the ratio of 1:1:1 by weight. The analysis of variance (ANOVA) at p = 0.05 was used to determine if there was a significant difference in the measured parameters of the dryers. The Duncan’s New Multiple Range Test (DNMRT) at p = 0.05 was used to separate the means where there was a significant difference. The drying rates were 0.23, 0.19, 0.16, and 0.13 kg/h for the DADD, DPDD, IADD, and OASD, respectively. The drying rate of the OASD was not significantly different from that of the IADD. The DPC was 1.53, 1.40, and 1.15 for the DADD, DPDD, and IADD, respectively. The DPC of the dryers were significantly different. The direct active desiccant dryer had the highest temperature of 45°C, the lowest relative humidity of 50% at the drying unit and the highest rate of moisture absorbed by the desiccant of 0.24 kg/h. The non-regenerative RHA desiccant had maximum moisture absorption of 28% of its weight. The direct active desiccant dryer is recommended for further development for use in humid tropical locations. Keywords: Crop, Desiccant, Dryer, Humid tropic, Performance, Solar.

Gravimetric Measurements of Moisture Uptake in Polyimide Films Used in Integrated Circuit Packaging

1989 ◽  
Vol 154 ◽  
Author(s):  
Denice D. Denton ◽  
Hartono Pranjoto
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Integrated Circuit ◽  
Dielectric Material ◽  
Measurement Techniques ◽  
Moisture Uptake ◽  
Electrical Measurements ◽  
Polyimide Films ◽  
Cure Temperature ◽  
Hygroscopic Behavior

AbstractPolyimide is used extensively in a variety of integrated circuit packaging applications. It is a good dielectric material with excellent planarizing capabilities, but like most polymers, it absorbs moisture. This hygroscopic behavior can lead to reliability problems in integrated circuit packages. The effects of variations in process history on moisture uptake are examined using gravimetric measurement techniques. In particular, the effects of cure schedule and exposure to high temperature/high humidity environments on steady state moisture uptake are reported. Steady state moisture uptake is shown to be a decreasing function of cure temperature. Moreover, the steady state moisture uptake in polyimide is greater after the samples have been “aged” in a high temperature and humidity ambient. Electrical measurements are used to examine the effects of cure temperature on diffusion kinetics of moisture in polyimide. The diffusion coefficient decreases with increasing cure temperature.

Effects of process history and aging on the properties of polyimide films

1991 ◽  
Vol 6 (12) ◽  
pp. 2747-2754 ◽  
Author(s):  
Denice D. Denton ◽  
Milan C. Buncick ◽  
Hartono Pranjoto
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Chemical Composition ◽  
Integrated Circuit ◽  
Dielectric Material ◽  
Measurement Techniques ◽  
Moisture Uptake ◽  
Bulk Chemical ◽  
Cure Temperature ◽  
Hygroscopic Behavior

Polyimide is used extensively in a variety of integrated circuit packaging applications. It is a good dielectric material with excellent planarizing capabilities, but like most polymers, it absorbs moisture. This hygroscopic behavior can lead to reliability problems in integrated circuit packages. The effects of variations in process history on moisture uptake are examined using gravimetric measurement techniques. In particular, the effects of cure schedule and exposure to high temperature/high humidity environments (85 °C/85% RH) on steady state moisture uptake are reported. Steady state moisture uptake is shown to be a decreasing function of cure temperature. Samples cured at 250 °C absorb 25% more moisture by weight than do samples cured at 400 °C. Moreover, the steady state moisture uptake in polyimide is greater after the samples have been “aged” in a high temperature and humidity ambient. The bulk and surface chemical composition are also monitored as a function of aging using Fourier transform infrared spectroscopy (FTIR) and electron spectroscopy for chemical analysis (ESCA), respectively. The PI surface chemistry degrades after 700 h in an 85 °C/85% RH environment. The bulk chemical composition appears to be unaffected.

Materials in Electronic Manufacturing: Electronic Packaging

MRS Bulletin ◽  
1992 ◽  
Vol 17 (4) ◽  
pp. 38-41
Author(s):  
Robert C. Pfahl
Keyword(s):  
Integrated Circuit ◽  
Electronic Packaging ◽  
Printed Circuit Boards ◽  
Dielectric Material ◽  
Cost Effective ◽  
Dielectric Materials ◽  
Electrical Performance ◽  
Wave Soldering ◽  
Effective Manner ◽  
Planar Substrates

Electronic packaging involves using an appropriate combination of conductive and dielectric materials to electrically interconnect and mechanically support electronic components in a reliable and cost-effective manner. Since the invention of the integrated circuit in 1959 and mass wave-soldering in 1958, the vast majority of electronic packaging has involved a planar substrate to which semiconductor devices in protective packages are attached by melting eutectic solder. The planar substrates or printed circuit boards (PCBs) were invented in 1940, but their widespread implementation was limited until the invention of mass soldering. PCBs use conventional epoxy-glass dielectric material with mass patterned conductive traces of copper, but alternative materials have been used for either enhanced electrical performance or lower product cost.

Evaluation of PTFE Nanoemulsion as a Low Dielectric Constant Material ILD

1996 ◽  
Vol 443 ◽  
Author(s):  
S. C. Sun ◽  
Y. C. Chiang ◽  
C. T. Rosenmayer ◽  
J. Teguh ◽  
H. Wu
Keyword(s):  
Dielectric Constant ◽  
Integrated Circuit ◽  
Moisture Absorption ◽  
Dielectric Material ◽  
Dielectric Strength ◽  
Index Of Refraction ◽  
Low Dielectric Constant ◽  
Nanoparticle Dispersion ◽  
Positive Photoresist ◽  
Low Dielectric

AbstractPolytetrafluoroethylene (PTFE) has been studied as a low dielectric constant material for ULSI. A novel nanoparticle dispersion of PTFE was developed that permits the spin-coat deposition of PTFE with a thickness range of 0.2 to 1.5 μm. These PTFE nanoemulsions are aqueous emulsions containing sub-50 nm size PTFE particles and surfactant that are thermodynamically stable, optically clear, and have low viscosity and surface tension. The films cast from this nanoemulsion are uniform in thickness with a standard deviation of < 2%. From FTIR spectra, significant amounts of C-F bonds (1153 cm−1 and 1211 cm−1) are detected in the films. The index of refraction from ellipsometry measurement is about 1.35 and the dielectric constant measured from high frequency C-V curves is about 1.85. The dielectric strength is about 170 V/ μm. TGA data indicates a weight loss rate of less than 0.25%/hr. at 425 °C. The moisture absorption is less than 0.01%. After sintering, the films are extremely resistant to chemical attack by sulfuric acid, buffered HF, and positive photoresist developer. The etch rate in an oxygen plasma at 30 W is around 200 nm/min. Stud pull tests indicate good adhesion to SiO2, Al, and Cu. Results of thermal, dielectric, chemical, and adhesion tests indicate that these PTFE films have potential for use as an integrated circuit dielectric material.

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

Slow rehydration improves the recovery of dried bacterial populations

1992 ◽  
Vol 38 (6) ◽  
pp. 520-525 ◽  
Author(s):  
J. W. Kosanke ◽  
R. M. Osburn ◽  
G. I. Shuppe ◽  
R. S. Smith
Keyword(s):  
Relative Humidity ◽  
Rhizobium Leguminosarum ◽  
Moisture Absorption ◽  
Rhizobium Meliloti ◽  
Bacterial Populations ◽  
Bulk Powder ◽  
Alfalfa Seed ◽  
Powder Samples ◽  
Cellular Stresses ◽  
Rhizobium Leguminosarum Biovar Trifolii

Slow rehydration of bacteria from dried inoculant formulations provided higher viable counts than did rapid rehydration. Estimates were higher when clay and peat powder formulations of Rhizobium meliloti, Rhizobium leguminosarum biovar trifolii, and Pseudomonas putida, with water activities between 0.280 and 0.650, were slowly rehydrated to water activities of approximately 0.992 before continuing the dilution plating sequence. Rhizobium meliloti populations averaged 6.8 × 108 cfu/g and 1328 cfu/alfalfa seed greater when slowly rehydrated from bulk powder and preinoculated seeds, respectively. Bulk powder samples were slowly rehydrated to 0.992 water activity by the gradual addition of diluent, followed by a 10-min period for moisture equilibration. Preinoculated seed samples were placed in an environmental chamber at 24 °C with relative humidity greater than 80% for 1 h to allow moisture absorption. "Upshock," osmotic cellular stresses that occur during rehydration, was reduced when dried microbial formulations were slowly rehydrated and equilibrated before becoming fully hydrated in the dilution plating sequence. These procedures may also be applicable when estimating total viable bacterial populations from dried soil or other dry formulations. Key words: rehydration procedure, microbial rehydration, desiccation, Rhizobium, Pseudomonas.

Experimental Study on Hygroscopicity of Rapeseed (Brassica Napus)

2012 ◽  
Vol 479-481 ◽  
pp. 2275-2278
Author(s):  
Ming Jin Yang ◽  
Wu Ming Xu ◽  
Tian Tang ◽  
Ling Yang ◽  
Feng Liu
Keyword(s):  
Experimental Study ◽  
Brassica Napus ◽  
Relative Humidity ◽  
Moisture Absorption ◽  
Early Period ◽  
Critical Relative Humidity ◽  
Temperature And Humidity ◽  
Higher Temperature

The hygroscopicity property of the rapeseed at different temperature and humidity was experimental studied in this paper. Tested results show that: the moisture absorption rates increase with the increase of relative humidity at the early period of absorption, and higher temperature leads to earlier reach of moisture equilibrium; the critical relative humidity(CRH) increases with the increase of temperature; the optional relative humidity for safety storage of rapeseed should be controlled less than 60%.

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