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.

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.

Cure of Hydrogen Silsesquioxane for Intermetal Dielectric Applications

1997 ◽  
Vol 476 ◽  
Author(s):  
J.N. Bremme ◽  
Y. Liu ◽  
K.G. Gruszynski ◽  
F.C. Dall
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
Dielectric Material ◽  
Structure And Properties ◽  
Hydrogen Silsesquioxane ◽  
Cure Time ◽  
Lower Temperature ◽  
Cure Temperature ◽  
Intermetal Dielectric ◽  
Temperature Time

AbstractCure is a significant process during back end of the line fabrication of integrated circuits with hydrogen silsesquioxane since it affects structure and properties of the spin on dielectric material. Reported herein is the effect of soak temperature, time, and oxygen concentration process parameters on structure and properties of hydrogen silsesquioxane. Results of the study emphasize the importance of an inert environment during the baseline recommended cure conditions of 400 °C for one hour in order to avoid oxidation and formation of polar silanol or water species. A 350 °C cure temperature is more robust to oxidation providing similar or improved properties. Shorter cure times result in similar structure and properties as the baseline cure which suggests that lower temperature and/or shorter cure time may provide value worth investigating by integrated circuit manufacturers.

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.

Sample Preparation of Aluminum Bridge Test Vehicles for Tem In-Situ Crystallographic Studies of Electromigration

1987 ◽  
Vol 115 ◽  
Author(s):  
W. E. Rhoden ◽  
J. V. Maskowitz ◽  
D. R. Kitchen ◽  
R. E. Omlor ◽  
P. F. Lloyd
Keyword(s):  
High Temperature ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Circuit Reliability ◽  
Test Vehicle ◽  
Aluminum Films ◽  
Current Densities ◽  
Integrated Circuit Reliability ◽  
A Current

IntroductionElectromigration in aluminum films has been identified as an increasing concern for integrated circuit reliability. Electromigration is the mass transport of atoms in a conductor under a current stress. Electromigration occurs in conductors experiencing current densities greater than 105 A/cm2 and is accelerated by high temperature. The damage to aluminum films manifests itself in the formation of voids, hillocks and whiskers along the conductor. This paper presents a test vehicle preparation procedure which can be used to investigate electromigration.

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