Polyimide film preparation

Observations Polyimide films prepared by (i) casting, (ii) volatilizing off a solvent to... 

Table II. Solubilities of Polyimide Films Prepared with 6F...

Recently, Interest has been shown in a solar sail to propel spacecraft through the solar system, using the pressure of sunlight on the sail as the driving force (1, ). A thin reflective metal-coated plastic film was required for the sail which would be stable for long periods of time to the severe temperature and radiation conditions encountered in space. One of the films considered for the solar sail was the polyimide film prepared from pyromellitlc dianhydride and bis-(4-amlnophenyl) ether (, ) 5... 

G.D. Fu, W.C. Wang, S. Li, E.T. Kang, K.G. Neoh, W.T. Tseng, D. J. Liaw, Nanoporous low-K polyimide films prepared from poly(amic acid)s with grafted poly(methylmethacrylate)/ poly(acrylamide) side chains, J. Mater. Chem. 13 (9)(2003) 2150-2156. 

Anderson M R, Davis R M, Taylor C D, Parker M, Clark S, Marciu D, Miller M (2001) Thin Polyimide Films Prepared by Ionic Self-Assembly. Langmuir 17 8380-8385. 

VDP Polyimides. Polyimide films have also been prepared by a kind of VDP (16). The poly(amic acid) layer is first formed by the coevaporation and condensation of two monomers, followed by copolymerization on the substrate. The imidization is carried out in a separate baking step (see POLYIMIDES). 

Cobalt(II) chloride was dissolved in poly(amide acid)/ N,N-dimethylacetamide solutions. Solvent cast films were prepared and subsequently dried and cured in static air, forced air or inert gas ovens with controlled humidity. The resulting structures contain a near surface gradient of cobalt oxide and also residual cobalt(II) chloride dispersed throughout the bul)c of the film. Two properties of these films, surface resistivity and bullc thermal stability, are substantially reduced compared with the nonmodified condensation polyimide films. In an attempt to recover the high thermal stability characteristic of polyimide films but retain the decreased surface resistivity solvent extraction of the thermally imidized films has been pursued. 

Metal ion modified polyimide films have been prepared to obtain materials having mechanical, electrical, optical, adhesive, and surface chemical properties different from nonmodified polyimide films. For example, the tensile modulus of metal ion modified polyimide films was increased (both at room temperature and 200 0 whereas elongation was reduced compared with the nonmodif ied polyimide (i). Although certain polyimides are )cnown to be excellent adhesives 2) lap shear strength (between titanium adherends) at elevated temperature (275 0 was increased by incorporation of tris(acetylacetonato)aluminum(III) (2). Highly conductive, reflective polyimide films containing a palladium metal surface were prepared and characterized ( ). The thermal stability of these films was reduced about 200 C, but they were useful as novel metal-filled electrodes ( ). 

I would like to express thanks to Kathleen Ginn for excellent technical assistance In preparing patterned polyimide films. 

The increasing importance of multilevel interconnection systems and surface passivation in integrated circuit fabrication has stimulated interest in polyimide films for application in silicon device processing both as multilevel insulators and overcoat layers. The ability of polyimide films to planarize stepped device geometries, as well as their thermal and chemical inertness have been previously reported, as have various physical and electrical parameters related to circuit stability and reliability in use (1, 3). This paper focuses on three aspects of the electrical conductivity of polyimide (PI) films prepared from Hitachi and DuPont resins, indicating implications of each conductivity component for device reliability. The three forms of polyimide conductivity considered here are bulk electronic ionic, associated with intentional sodium contamination and surface or interface conductance. 

LB films prepared from polyimide Absorption spectra and conductivity... 

High adhesive polyimide films were prepared by Kaneshiro et al. (2) consisting of 2,2-bisaminophenoxylphenylpropane and paraphenylene diamine, pyro-mellitic dianhydride, and 3,3, 4,4 -benzophenone tetracarboxylic dianhydride. 

Adhesive films consisting of thermoplastic polyimides were prepared by Yanagida et al. (3) consisting of 4,4 -oxydianiline, p-phenylenedi amine, and... 

F-BDAF Tg for various blend compositions, see Fig. 14. The microphase-separated morphology further manifests itself in the self-adhesion behavior of polyimide films derived from such mixtures. For mixture containing at least 25 wt% of the flexible component, peel tests of polyimide bilayer samples prepared by solution casting, bulk failure of the test specimens was observed. Since the flexible component contained fluorine, the samples could be examined by X-ray photoelectron spectroscopy to determine the surface composition. At only 10% loading, the flexible component comprised 100% of the top 75 A of the sample. The surface segregation of the flexible component is believed to be responsible for the adhesion improvements. 

Aromatic polyimides have excellent thermal stability in addition to their good electrical properties, light weight, flexibility, and easy processability. The first aromatic polyimide film (Kapton, produced by DuPont) was commercialized in the 1960s and has been developed for various aerospace applications. The structure of a typical polyimide PMDA/ODA prepared from pyromellitic dianhydride (PMDA) and 4,4 -oxydianiline (ODA), which has the same structure as Kapton, is shown in (1). Aromatic polyimides have excellent thermal stability because they consist of aromatic and imide rings. 

Fluorinated polyimide (PMDA/TFDB) and nonfluorinated polyimide (PMDA/DMDB) films prepared on a silicone substrate were introduced into an electron beam lithography system and subsequently exposed for square patterns (4x4 mm). The electron beam energy was 25 keV the beam current was 10 nA, and the beam dose was 300-1500 pC/cm. The 4x4 mm square was written by a 0.1-pm-wide electron beam. 

Aromatic polyimides have many anisotropic imide rings and benzene rings, and they are easy to orient by a film-forming process. Molecular orientation in polyimide films causes in-plane/out-of-plane birefringence (AnJ. Russell et al. have reported the A/ / of conventional PMDA/ODA. On the other hand, spin-coated polyimide films just after preparation do not cause Ann, as noted in the... 

Polyimides. In situ co-deposition of metal salts such as Co(II), or LiCl into a polyimide precursor from 3,3, 4,4 -tetracarboxybenzophenone dianhydride and 4,4 -diaminobenzophenone with subsequent thermal curing offers surface-conductive polyimide film [43]. By similar procedures, Taylor et al. prepared a series of polyimides modified with Pd, Pt, Ag, Au, Cu, Sn, Ti and magnetic-Fe [44, 45, 46]. 

US 5,204,399 (American) 1991 Thermally conductive thermoplastic polyimide film die attach adhesives and their preparation National Starch and Chemical Investment Holding Corp. R Edelman Adhesive formulations having excellent die shear strength A polyimide-siloxane was prepared from aromatic amines, bis aminophe-noxybutylsiloxane and aromatic dianhydrides... 

JP 62246978 (Japanese) 1987 Heat-resistant adhesives containing siloxanes and imide-containing resins Shin-Etsu Chemical Industry Co. Ltd., Japan S Ueno, N Nakanishi, S Hoshida Adhesives showed good adhesion and flexibility useful in the preparation of flexible laminates Resin was prepared from the reaction product of bismaleimides, diamines, amino-terminated siloxanes and a bisphenol A cyanate adduct. The adhesive formulation was used on polyimide films... 

Kanakarajan K, Freuz JA. Flexible multilayer polyimide film laminates and their preparation. Eur Pat Appl EP 474054 A2 920311 21 pp... 

CoO-coated Co cluster and oxide-coated Fe cluster assemblies were prepared by a plasma-gas-aggregation cluster-beam-deposition technique [37-39]. For preparation of CoO-coated Co cluster assembly, oxygen gas was introduced through a nozzle near the skimmer into the deposition chamber. The Co clusters with CoO shells were formed before deposition onto the substrate [37], Figure 8 shows a TEM image of the clusters produced at oxygen gas flow rate R(02) = 1 seem. Clusters are almost monodispersed, with the mean diameter of about 13 nm. Electron diffraction pattern indicated the coexistence of Co and CoO phases. The cluster assemblies were formed on a polyimide film with a thickness of about 100 nm. 

For polymer film preparation, especially for the investigation of polymer-on-metal interactions, a molecular beam deposition (MBD) technique is necessary. This technique was first demonstrated for polyimide by Salem and co ... 

Sample Preparation. PMDA-ODA polyimide films were prepared by spin coating polyamic acid onto silicon wafers and curing to 360°C for 1 hour. The cured film thickness was approximately 10 pm. These samples were treated downstream of an 85% CFi -15% 02 microwave plasma for 30 minutes to produce a fluorinated layer, approximately 600 thick (16). Fluorinated layers less than 600 thick were obtained by additional treatment downstream from an 02 rich (85%) microwave plasma for various times. PTFE films (25 pm thick) were used as received from E. I. duPont de Nemours Inc. 

In this article we discuss the core level spectra of solventless prepared poly (N,N -(p,p -oxydiphenylene) pyromellitamic acid) or PMDA/ODA polyamic acid (PAA) films with particular emphasis on the chemical composition and on the Ols and Cls "shake up" transitions. Both vapor deposited polyamic acid and the resulting polyimide films show an excess of oxydianiline (ODA) and a deficiency of carbonyl groups. 

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