ABSTRACTS



The following is a list of the abstracts for papers which will be presented in the INTERNATIONAL SYMPOSIUM ON POLYMERS IN MICROELECTRONICS by presenting author. This list is updated continually to add abstracts as they become available and make appropriate corrections. This list may be conveniently searched by using the editor provided with most popular browsers (e.g. Microsoft Explorer, Netscape, ... etc.)


Marie Angelopoulos; IBM T.J. Watson Research Center, P.O. Box 218, Room 19-203, Yorktown Heights, NY 10598

E-Beam Resists for Advanced Mask and Device Making



(Abstract not yet available


)



Monica Bauer; Fraunhofer Institute of Applied Materials Research, Kantstrasse 55, D-14513 Teltow, GERMANY



New Results about Cyanate Resins for Microelectronics



Cyanate resins are resins possessing a combination of ideal mechanical properties which are retained at low and high temperatures for a longer time, which are easy to process and which show a good adhesion between materials. Other useful properties are low moisture uptake and stability, low dielectric constant, low optical loss, chemical and solvent resistance, inherent low flammability, high resistivity, no outgasing, rapid (snap) cure and last but not least, environment- friendly structure and stability.



First of all they were developed for aircraft and space application. Today similar materials are key materials in the electronics industry. They are needed as adhesives, packaging materials, underfills, binders for printed circuit boards, wave guide material etc..



New results will be reported during the presentation.


C. Uhlig1, O. Kahle1, J. Keller, B. Wieneke2, M. Bauer1

1) Fraunhofer Institute for Reliability and Microintegration, Branch Lab Polymeric Materials and Composites, D-14513 Teltow, Germany



2) LaVision GmbH, D-37079 Göttingen, Germany



Optical Crack Tracing, A New Method to Automatically Measure Fracture Toughness and a Great Step Forward in Ensuring High Accuracy, Efficiency and Independence of the Operator



Static fracture toughness testing of polymers according to the standards involves the analysis of only the crack initiation event and fracture toughness for initiation is calculated from a single pair of load and crack length data. An alternative way is the measurement of the R-curve, which gives the fracture toughness both for initiation and propagation. By measuring the R-curve for 500 compact tension specimens (consisting of different one and two phase (toughened and non-toughened) thermosetting materials) it was found that accuracy and reliability of fracture toughness testing can be significantly improved over the level which seems possible to achieve with the manual procedure recommended in the standards. At the same time, a much higher degree of information is obtained about time-dependent fracture phenomena.

So far, the lack of efficiency of existing methods for the R-curve measurement prevented the use of this concept on a broader routine basis. With "Optical Crack Tracing", a new optical method employing image analysis, the R-curve can be measured automatically and very efficiently, since no additional specimen preparation and calibration is required and the manual analysis to measure fracture toughness which is described in the standards can be replaced by an automatic measurement.


Carlye Case; Lucent Technologies, Murray Hill, NJ 07974

Low Dielectric Constant Polymers in Optoelectronic Applications



(Abstract not yet available)


Ralph R. Dammel; AZ Electronic Materials, Clariant Corporation, Somerville, NJ 08876

Beyond DUV: The Role of Photoresists in The Next Lithography Generations



The photolithographic process has historically been the pacesetter for the semiconductor industry by determining what mask features can still be printed with high fidelity. Photolithography plays a central role in the reduction of feature sizes that drives Moore's law and hence the industry's profitability, a role that is reflected in the high investment the industry is willing to make for periodic re-tooling of the photolithography equipment. The pace of this re-tooling is accelerating greatly, with DUV (248 nm) lithography scheduled to be replaced by 193 nm lithography on the most advanced levels already in the 2002-2003 timeframe. Beyond 193 nm lies what is probably the last optical lithography technique, 157 nm lithography, and/or the Next Generation Technologies, Extreme UV (EUV) and Electron Projection Lithography (EPL).



This presentation will explore the contribution of photoresist materials to the performance of these new techniques as well as to extending the life of existing ones. The historic contribution of photoresists will be judged by a benchmark measuring resist performance vs., e.g., stepper contributions. The design challenges and approaches that face the resist chemist and the photolithography engineer for the new technologies will be discussed as well as the strategies currently being pursued to meet these requirements.


M. Dalil Rahman, Munirathna Padmanaban, Jun-Bom Bae, Woo-Kyu Kim, Takanori Kudo, Douglas McKenzie and Ralph R. Dammel; AZ Electronic Materials, Clariant Corporation, Somerville, NJ 08876

Layer-Specific Resists for 193nm Lithography



Methacrylate polymers containing pendant cyclic groups such as adamantane and main chain cyclo-olefin polymers with or without maleic anhydride have emerged as the polymers of choice for 193 nm lithography. This paper will present data on resist formulations containing poly(2-methyladamantyl methacrylate-co-mevalonic lactone methacrylate) as well as copolymers based on derivatives of norbornene and maleic anhydride. Lithographic results so far indicate that the methacrylate containing formulations are particularly advantageous for 1:1 dense lines and contact hole applications, whereas the cyclo-olefin based formulations show superior performance for semi-dense and isolated line applications. It is expected that resist materials based on these chemistries would be used for the first generation device manufacturing.



In this paper, lithographic results are presented for AZEXP AX1020P, AZEXP AX1030P, and AZEXP AX2000P resists which have been designed for contact hole, dense and isolated line applications, respectively. In addition, some of the common issues of current 193nm resists are discussed, such as linewidth slimming, line-edge roughness and shelf life.


F. Faupel, A. Thran, M. Kiene, T. Strunskus, V. Zaporojtchenko, and K. Behnke Lehrstuhl für Materialverbunde, Technische Fakultät der Universität Kiel, Kaiserstr. 2, 24143 Kiel, GERMANY E-mail: ff@techfak.uni-kiel.de

Diffusion and Interface Formation During Noble Metal Deposition onto Fully Cured Low-k Polymers



The increasing application of polymers in microelectronics, particularly their potential use as low dielectric constant materials in integrated circuits has aroused much interest in diffusion of noble metals in polymers and the formation of the metal-polymer interface. Various investigations, involving surface spectroscopy, electron microscopy, ion scattering, direct radiotracer measurements, and Monte Carlo simulations have contributed considerably to our understanding of metal diffusion as well as the nucleation and growth behavior of metal films on polymers [1]. Noble metals grow on polymers by a Volmer-Weber mode, i.e., by cluster formation. Nucleation either occurs at preferred sites at the surface or randomly. In random nucleation the critical nucleus consists of only a single atom [2]. This reflects an extreme aggregation tendency. Condensation coefficients can be very low in the early deposition stages which are most important in controlling the microstructure of the m!

etal film [3]. While noble metals were clearly shown to be able to diffuse into polymers at low evaporation rates they are effectively immobilized by their strong aggregation tendency. Due to this tendency and the high metal cohesive energy no diffusion into polymers is to be expected from a continuous metal film even at elevated temperatures [4]. Reports in the literature on strong metal diffusion are discussed in terms of metal clustering at the surface which mimics diffusion into the bulk in surface analytical techniques relying only on the decay of the metal intensity upon annealing. Despite the lack of significant diffusion from continuous films diffusion barriers may be required in chip applications because trace amounts of metal are able to diffuse into polymers in the initial deposition regime, where isolated atoms impinge on the pure polymer surface [1]. However, the barrier requirements with respect to thickness, e.g., should be much less stringent than in the polyme!

r-on-metal case. Here chemical reactions may occur between the polymer precursor and the metal involving the formation of metal ions. Metal ions are highly mobile and do not aggregate due to electrostatic repulsion. Moreover, their transport is strongly enhanced by the high electrical fields existing in chip applications [5].



[1] F. Faupel, R. Willecke and A. Thran, Mater. Sci. Eng. R 22, 1 (1998).



[2] V. Zaporojtchenko, T. Strunskus, K. Behnke, C. v. Bechtolsheim, M. Kiene, F. Faupel,

J. Adhes. Sci. Technol. 14, 491 (2000).



[3] A. Thran, M. Kiene, V. Zaporojtchenko, and F. Faupel, Phys. Rev. Lett. 82, 1903 (1999).



[4] M. Kiene, T. Strunskus, R. Peter, and F. Faupel, Adv. Mater. 10, 1357 (1998).



[5] F. Faupel, A. Thran, V. Zaporojtchenko, M. Kiene, T. Strunskus, and K. Behnke, in: Stress-Induced Phenomena in Metallization, 5th Int. Workshop, O. Kraft, E. Arzt, C. A. Volkert, P. S. Ho, and H. Okabayashi (Eds.), AIP Conf. Proc. 491, Stuttgart 1999.


N. E. Iwamoto; Honeywell Electronic Materials, 10080 Willow Creek Road, San Diego, CA 92131

Approaching Adhesion and Process Issues for Microelectronics Packaging Concerns Using Molecular Modeling



Higher interconnect densities, chip scale, chip-on-board, and 3D packaging considerations in the microelectronics packaging world have lead to higher polymer and interfacial performance demands while at the same time the broader applications in telecommunication, personal computing and the internet have pushed suppliers toward seeking cost effective development methods and materials. These concerns have lead directly to the need for simulation tools to predict and design materials for the more rigorous performance environments. They will continue to be important as feature sizes shrink and the interfacial properties become as important (or even more important) than the bulk material properties in predicting failure.



At Honeywell, we have simulated material performance using molecular modeling in order to understand basic concepts such as wetting, bleed and adhesion and have made use of the information found to understand how our materials are acting in stressed environments. We have also studied stress cycling events on a molecular scale, as well as process cycle issues, which have allowed us to make better choices in materials for both formulation and process. For instance, we have found a molecular-scale Coffin-Manson type of relationship in the polymer interfaces under study, and we have also found that we could use the derived simulation correlations to refine and improve performance. The materials under study have all been polymer-based adhesives and resins used for die attach, underfill, viafill and board build-up and have involved looking at both the adhesive and cohesive concerns. Our studies have found that contributions from the molecular structure to these application performances can be simulated very simply and easily but are best used to correlate trends rather than to determine absolute mechanical properties. These studies will be summarized in this talk.


C. Janowiak1, S. Ellingboe2 and I. Morey

1) Lam Research Corporation, 4400 Cushing Parkway, Fremont, CA 94538-6401

2) Lam Research Ireland, Collinstown Industrial Park, Leixlip County Kidare, Ireland

3) Lam Research Singapore, 21 Serangoon North Ave. 5,#05-02 Ban, Singapore



SiLK Etching on the Lam Research Corporation 4520XLE



Various processes were investigated to etch the low k dielectric material SiLK. Because SiLK is a polymeric material, the two main process options are either an oxidizing or a reducing etch gas mixture which use either oxygen or hydrogen as the main etchant gas respectively. Hydrogen-based etch processes were found to have a large process window, but slow etch rates and minimal profile control. When oxygen was used as the primary etch gas, a hydrocarbon was added for sidewall passivation. These oxygen-based processes demonstrated higher etch rates, and the addition of ethylene provided more control of the etch profile. The oxygen to ethylene flow ratio was found to be the dominant factor controlling the etch profile. Reduced hardmask faceting was achieved by running with low RF power for both the hydrogen-based and oxygen-based processes. Significant changes in etch rate, profile angle and hardmask faceting were observed as the photoresist was cleared from the hardmask during the etch. These changes are caused by the changing etch chemistry as a result of the dramatic reduction in the area of organic film exposed to the plasma. Finally, the transfer of the final process to another organic film, FLARE, was demonstrated.


Sakthi Kumar; Thin Film Lab, Dept. of Physics, Indian Institute of Technology, New Delhi, 110 016 INDIA

Dielectric Properties of Plasma Polymerized Lemongrass Oil Thin Film Capacitors



The dielectric properties of radio frequency plasma polymerized Lemongrass oil (a Natural Oil )thin film capacitors have been studied in the frequency range 3 KHz. to 9 MHz. at various temperatures 303 K to 393 K. The dielectric constant is found to increase with the increase in the film thickness. The large increase in the capacitance towards the low frequency region indicates the possibility of an interfacial polarization mechanism prevailing in that region. Very high value of the dielectric constant of this polymer gives a remarkable importance in the field of capacitors.


Kenneth Liechti; University of Texas, Austin, TX 78712

Effect of Polyimide Processing on Adhesion



(Abstract not yet available)


Fotios Papadimitrakopoulos; Department of Chemistry, Polymer Science Program, Nanomaterials Optoelectronics Laboratory, Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136

Utilizing Polymeric Metal Chelates and Their Self-Assemblies for LED Applications



Aluminum (III) 8-hydroxyquinoline (Alq3) metal chelate, one of the most stable electron-transporting compound currently available, has been instrumental for the development of organic light-emitting diodes (OLEDs). Following a brief overview of the current status of OLED technology, the chemical and structural transformation leading to device deterioration will be discussed in lieu of the continuous strive to improve performance. Recent advances in metallorganic self-assembly of difunctional bisquinoline chelates with a variety of zinc precursors to form polymeric coordination assemblies are introduced. The potential of this method to produce insoluble and intractable structures of controllable supramolecular architecture suitable for semiconducting applications has stimulated an in-depth investigation of the growth mechanism of these polymeric chelates. The packing characteristics and growth coverage of these films originate from a number of Zn-mediated association mechanisms that are particularly important in yielding pinhole free assemblies. This is further extended into rare earth metal-chelating poly(urethaneurea-block-polyethylene oxide) copolymers based on 2,6-diaminopyridine. The combination of self-organization of block copolymers along with the well-defined emission characteristics of rare-earth metals is discussed in light of a wide range of applications of such chelates in photonic devices.


R.A. Pearson, B. J. McAdams, R. O. Oldak and D. J. Welsh; Microelectronics Packaging Materials Lab - Lehigh University, 5 East Packer Ave., Bethlehem, PA 18015

Strengthening Underfill/Passivation Interfaces for Flip-Chip Assemblies



Untreated polyimide passivation layers often result in poor adhesion (Gc <30 J/m2) with most underfill resins used in flip-chip assemblies. However, some underfill resins bond well to polyimide (Gc > 60 J/m2) while others bond well to polyimide after UV/Ozone or oxygen plasma treatments. Improvement in adhesion can be attributed to increasing amounts of polarity on the surface although surface roughening and etching of a weak boundary layer have also been cited as a possible cause for the improvements in adhesion. In this work, FTIR, XPS and flow microcalorimetry will be used to describe the polarity of the polyimide surface. An asymmetric double cantilever beam will be used to determine the adhesion at model epoxy - polyimide interfaces.


Zhonghua Peng; Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110

Novel Organic and Polymeric Materials for Photonic Applications



The role of polymers in the electronics industry, traditionally as insulating materials, has changed dramatically in the last twenty years. It is now known that polymers can be fabricated as active components in a number of electronic devices, such as thin-film transistors, light-emitting diodes, electro-optic modulators, etc. The driving force for pursuing polymer materials in such device applications lies in the ease of fine-tuning material properties, low-cost processing conditions, and excellent physical and mechanical properties. The challenge for a material chemist is to rationally design a polymer with desired properties. Our research has been focused on the design, synthesis, and characterization of novel functional organic and polymeric materials. This presentation will give an overview of our research efforts in areas of polymer light-emitting diodes, light-harvesting dendrimers and self-assembled polymer networks.


Terho Kololuoma, Ari Kärkkäinen and Juha T. Rantala; VTT Electronics

Kaitoväylä 1, 90570 Oulu, Finland



Hybrid Materials for Optoelectronics Manufacturing

The sol-gel method can be applied for the fabrication of electrical and optical materials and structures. Due to the ease of modifying material properties at the molecular level the sol-gel technique allows the fabrication of various material compositions by applying liquid phase deposition. Furthermore, the technique is attractive due to its low equipment and processing costs. This paper generally describes different materials that we have developed for electronics and optoelecronics applications such as lithographically patternable glasses and ceramics, oxide semiconductors and electro-optical materials.


Antonino Scandurra1, Giuseppe Currò2, Ferruccio Frisina2 and Salvatore Pignataro3

1) Laboratorio Superfici ed Interfasi - Consorzio Catania Ricerche, c/o ST Microelectronics, Stradale Primosole 50, 95100 Catania, ITALY. e-mail superlab@alpha4.ct.astro.it.

2) STMicroelectronics, Stradale Primosole 50, 95100 Catania, ITALY.

3) Dipartimento di Scienze Chimiche Università di Catania, Viale A. Doria 6, 95125 Catania, ITALY.



Corrosion Inhibition of Al Metal in Microelectronic Devices Assembled in Plastic Packages



Aluminium based metallizations are extensively used as electrical interconnections of integrated power microelectronic devices. It is well known that this metal exposed to moisture is highly sensitive to corrosion. This is due to the chemical interaction of aluminium with water. Traces of halogens and other chemical species coming from molding compound as well as chip fabrication processes increase the corrosion rate because they represent catalysts for the above reaction. In this paper we report a study of some treatments of Al passivation against corrosion in moisture. The proposed process can be done on finished wafer without any damage of other device materials and satisfies the die attaching and wire bonding requirements. It consists of a simple chemical dipping into an organic bath containing ortophosphoric acid. The passivation behaviour of the resulting surfaces has been checked by means of pressure cooker test both on wafer and assembled power MOS devices in plastic package. The surfaces resulting in each process step have been analysed by means of ESCA. An interpretation of the properties of the resulting passivated surface is proposed.


Antonino Scandurra1, Roberto Zafarana2, Yuichi Tenya3, and Salvatore Pignataro4



1) Laboratorio Superfici ed Interfasi - Consorzio Catania Ricerche, c/o ST Microelectronics, Stradale Primosole 50, 95100 Catania, Italy,e-mail superlab@alpha4.ct.astro.it.

2) STMicroelectronics, Stradale Primosole 50, 95100 Catania, Italy.

3) Toshiba Chemical Corporation, Hankyu Express Building, 3-9, 3-chome, Shimbashi, Minato-ku, Tokyo 105-0004, Japan.

4) Dipartimento di Scienze Chimiche Università di Catania, Viale A. Doria 6, 95125 Catania, Italy.



Molding Compound Additives Causing Adhesion Failure at Chip Interface in Electronic Devices



Today the microelectronics market requires devices with failure level approaching zero. To obtain this goal all production processes must be put to extreme quality control. The molding is one of the most critical assembly process of power plastic packages. This is due to the high complexity of chemistry involved in the molding compound - lead frames and die interfaces. In particular adhesion of molding compounds is heavily influenced by surface chemistry of lead frames and die. In turn, for a given chemical composition of the lead frame or of the die, the formulation of the molding compound is the critical parameter and the chemical control of the interfacial zone during fabrication processes represent the key to guarantee high devices reliability. On this regard it is to note that very often adhesion failure at molding compounds - chip and molding compound - lead frame interfaces may lead to the electrical failure of the entire microelectronic device. This paper reports an adhesion study of epoxy - phenolic molding compounds onto the most relevant surfaces faced in the power devices assembled in plastic packages like CuOx-Cu(OH)y, NiOx-Ni(OH)y, AlOx, SiNx, SiOx. The work was done by combining delamination (Scanning Acoustic Microscopy) and pull strength data with the interface chemistry studied by means of ESCA. The paper reports some important adhesion failure phenomena found in these systems.


Daniel Scheck; The Dow Chemical Company, 3021 Cornwallis Road, Research Triangle Park, NC 27709

Cyclotene® (Bcb) Polymer Thin Films for Microelectronic Applications



Polymeric materials, in the form of thin films, are finding large and increasing use in a variety of microelectronic applications and devices. Solder bumping and flip chip are rapidly growing packaging strategies. These usually require a polymer dielectric layer for passivation and for redistribution of peripheral I/O pads to an area array. There is also rapidly growing interest in wafer level packaging. Many designs have emerged, and in most cases polymer dielectric layers are an essential part of the design. Polymer dielectrics are used in many other microelectronic applications as well, such as passivation of silicon and GaAs devices, multilayer interconnects, integration of passive components, planarization layers for active matrix flat panel displays, in high density build-up boards, in MEMS as a protective layer during silicon etching, in polymeric optical waveguides, and as an interlayer dielectric. Desirable properties for a polymer to be used in these areas include good thermal stability, high Tg, low dielectic constant, low water uptake, and simple processing. Cyclotene® (BCB) resins, which are available in both photosensitive and non-photosensitive grades, meet these requirements and are gaining increasing acceptance in these markets. The properties of Cyclotene polymers, and examples of their use in each of the applications listed above, will be presented.


A. Sun1, P. Bronecke1, W. Kritzler1, C. Moyer1, G. Yan1 ,C. Blair2, G. Riddle2, and S. Kaplan3

1) Lockheed Martin - GES, Moorestown, NJ

2) Bryte Technologies, Morgan Hill, CA

3) 4th State Inc., Belmont, CA





COTS Approach to Military T/R Module Fabrication



Lockheed Martin Navel Electronics and Surveillance Systems (LM-NE&SS) in Moorestown, NJ is committed to developing low cost microwave transmit/receive (T/R) modules utilizing Lockheed Martin's High Density Interconnect (HDI) technology. The HDI technology uses a multilayer thin film process to define the interconnects for multichip modules (MCM). The multilayer structure is produced by depositing and patterning thin film copper interconnects onto Kapton E® and then laminating additional layers of Kapton E® film coated with an adhesive system and repeating the metal deposition and patterning processes. The adhesive system used to laminate the Kapton® films is a specially formulated siloxane polyimide epoxy (SPIE). The existing process of applying the SPIE to the Kapton® film is a manual batch process that is time consuming and labor intensive.

The overall goal of this project is to reduce the cost of the existing adhesive process by 30X without sacrificing performance. The cost reduction will be achieved through the identification of a lower cost adhesive system, the utilization of a high volume coating process to reduce the labor cost and the increase in the carrier size resulting in a lower per unit module cost. To this end, NE&SS has teamed up with GE-Corporate Research and Development (CR&D), Bryte Technologies, and 4th State Inc. to develop a COTS low cost Kapton® film precoated with adhesive to be used in the manufacturing of multilayer MHDI multichip modules (MCM). Bryte Technologies Inc. is a manufacturer of advanced composite materials and 4th State provides plasma treatment services.

This project is funded by the Navy Mantech program through the American Competitive Institute (ACI) as part of the Affordable Microwave Packaging System (AMPS) Program. The AMPS program is aimed at reducing the total cost of microwave T/R modules manufactured in high volume for use in solid state phased array radar systems.


Ch. Uhlig; Fraunhofer IZM, Kantstr. 55, D-14513 Teltow, GERMANY

Optical Crack Tracing, A New Method



(Abstract not yet available)


Rohit H. Vora 1, 2, P. Santhana Gopala Krishnan1, S. Veeramani1, Suat Hong Goh2 and Tai-Shung Chung 1, 3

1) Institute of Materials Research and Engineering (IMRE)

3, Research Link, Republic of Singapore 117602

2) Department of Chemistry, National University of Singapore

10 Kent Ridge Crescent, Republic of Singapore 119260

3) Department of Chemical and Environmental Engineering

10 Kent Ridge Crescent, Republic of Singapore 119260



Fluoro-Polyimides and CoPolyimides: Synthesis and Thermal Degradation Kinetics Studies



Aromatic fluoro-polyimides and copolyimides based on 6FDA, Durene diamine, 2,6 daminotoluene (2,6-DAT) and 3-phenylenediamine (m-PDA) were synthesized having various mole concentrations of diamines in N-Methyl-2-pyrroidone (NMP). The thermal degradation kinetics of these two series of linear condensation polyimides and copolyimides were studied using Thermogravimatric analysis and their activation energy was determined Coats and Redfern equation. The activation energy was found to increase with increase in mole ratio of 2,6-DAT in [6FDA-Durene diamine (n%) + 2,6-DAT (m%)], whereas the glass transition temperatures decrease with the increase in mole ratio of m-PDA in [6FDA-Durene Diamine (n%) + m-PDA (m%)] copolyimide series respectively. The Tgs predicted from Fox equation are lower than the experimental data and their difference increases with decrease in Durene diamine contents. The polymers fond have solubility in many common organic solvents.


Elizabeth Walker; Senior Product Supervisor, Emerson & Cuming, 46 Manning Road, Billerica, MA 01821

Observations of Reliability Changes of an Epoxy Encapsulated Power Supply Under Aggressive Environmental Conditions



Several epoxy based encapsulants are utilized in the commercial production of many types of electrical components including power supply assemblies. One epoxy encapsulant was found to change the electrical performance of the power supply as the environmental conditioning level became more aggressive.



A study was initiated to explain the relationship of the epoxy composition as it related to the observed affects. The findings of this investigation of corrosion and electrical failures of copper wire coil assemblies, encapsulated with fast gelling, low temperature cured epoxy, exposed to accelerated environmental conditions under bias will be discussed.



Data is presented from lab tests run on encapsulated coil assemblies, connected in parallel to a 100 volt source, subjected to 40C / 90%RH and 85C / 85% RH for 500 to 2000 hours. A high incidence of electrical failures; opens and shorts determined by continuity testing, was indicative of corrosion within the parts. Corrosion sites on the wire were confirmed by x-ray at the end of the testing period. Data is presented for several amine hardeners and accelerators. Possible mechanisms of corrosion within the encapsulated coil unit and factors which could contribute to corrosion were considered. Focus was placed on the contribution of amine curing agents and accelerators in electrolytic corrosion of the copper wires. The effect of the hardeners and accelerators on cure time, physical properties and surface appearance, as well as extractable ions and conductivity, and results of electrical testing under accelerated environmental conditions are compared . Stoichiometry, chemistry and test conditions will be discussed as they relate to electrolytic corrosion of the copper wires.


G. H. Yang, E. T. Kang, and K. G. Neoh; Dept. of Chemical Engineering, National University of Singapore, Kent Ridge, SINGAPORE 119260

Surface Modification of Poly(tetrafluoroethylene) Films by UV-Induced Graft Copolymerization and Plasma Polymerization for Adhesion Enhancement with Electrolessly Deposited Copper



Surface modification of Ar plasma-pretreated poly(tetrafluoroethylene) (PTFE) films, either by UV-induced graft copolymerization with N-containing monomers (4-vinyl pyridine (4-VP) and 2-vinyl pyridine (2-VP)), or by plasma polymerization and deposition of glycidyl methacrylate (GMA), was carried out for adhesion enhancement with the electrolessly deposited copper. For the PTFE surfaces grafted with the N-containing polymers, electroless deposition of copper could be carried out in the absence of SnCl2 sensitization. The so-deposited copper layer exhibited substantially higher adhesion strength over that deposited in the presence of SnCl2 sensitization. T-peel adhesion strength in the order of 6 N/cm, with cohesive failure inside the PTFE substrate during delamination, could be readily obtained for the electrolessly deposited copper on the graft-modified PTFE surfaces.


Yan Zhang1, K. L. Tan1 and E. T. Kang2

1) Dept. of Physics, National University of Singapore, Kent Ridge, SINGAPORE 119260

2) Dept. of Chemical Engineering, National University of Singapore, Kent Ridge, SINGAPORE 119260



Thermal Imidization of Poly(amic acid) Precursors on Modified Si(100) Surface From UV-Induced Graft Polymerization and Plasma Polymerization of Glycidyl Methacrylate



Polyimides (PI) have been used extensively in the packaging and fabrication of microelectronics devices and integrated circuits. However, the poor adhesion of thermally-imidized PI films to the silicon substrates demands the surface modification of the latter. As an alternative to silane treatment of the Si surface, an adhesion promotion layer was incorporated on the Si(100) substrate surface via either UV-induced graft polymerization of glycidyl methacrylate (GMA) (the GMA-g-Si surface), or by direct plasma polymerization and deposition of GMA (the pp-GMA-Si surface). Thermal imidization of the poly(amic acid) precursors of PMDA-ODA-based PI and fluorinated PI's on the GMA polymer-modified Si surface resulted in 180o-peel adhesion strength in the order of 10 N/cm. The strong adhesion was attributed to the synergistic effect of coupling the curing of epoxide functional groups in the grafted GMA polymer layers with the imidization process of the poly(amic acid)s, and the fact that the GMA chains were covalently tethered on the Si(100) surface.


Haipeng Zheng and James P. Bell; Polymer Program, Institute of Materials Science, U-136, University of Connecticut, Storrs, CT 06269-3136

Fluorinated Coatings Formation by Spontaneous Polymerization



The use of fluorinated coatings is very attractive due to their special characteristics such as hydrophobicity, chemical stability, weather resistance and a low coefficient of friction. Here two fluorinated monomers -- N-(4-fluorophenyl) maleimide (4FMI) or N(3-trifluoromethylphenyl) maleimide (3TMI) were synthesized and introduced into a spontaneous polymerization system: a new process to grow protective, temperature resistant, and insulating coatings directly onto metal parts including complex topographic objects. The fluorinated maleimides were copolymerized with styrene, a coupling agent and a bis-maleimide cross-linker. ATR-FTIR spectra and contact angle data show the polymer coatings have more fluorinated units when the ratio of fluorinated monomers increased. The approximate content of each unit of the polymer coatings can be farther calculated from XPS data. It was found that the greater the fluorine-content, the lower the dielectric constant and the better the wet-adhesion, water impermeability and corrosion resistance on aluminum. However, compositions with high fluorine content were more brittle.