Stress in polyimide films having a rodlike molecular skeleton formed on a silicon substrate

Nomura, Hideshi; Eguchi, Masuichi; Asano, Masaya

doi:10.1063/1.349790

Cited by 13 publications

(3 citation statements)

References 9 publications

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“…They also showed that the presence of a metal frame which supports PAA films during imidization (bifix-cure) lowers the TEC of the resulting PI films and inferred that the decreased TEC results from an enhanced molecular orientation. Numerous papers described that the TEC mismatch between a substrate such as Cu and the PI film is responsible for delamination at the interface and cracking in the PI film. ,− …”

Section: Introductionmentioning

confidence: 99%

“…Numerous papers described that the TEC mismatch between a substrate such as Cu and the PI film is responsible for delamination at the interface and cracking in the PI film. 3,[5][6][7][8][9][10] Recently, a high-temperature annealing method in which aromatic PI films were used as a precursor was developed to obtain a highly crystalline graphite applicable as a monochromator for X-ray analysis. In this method, the high-temperature annealing of PI films cured in a frame provided highly crystalline graphite, whereas that of the films cured free-standing did not.…”

Section: Introductionmentioning

confidence: 99%

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Spontaneous Molecular Orientation of Polyimides Induced by Thermal Imidization. 2. In-Plane Orientation

et al. 1996

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The degree of in-plane molecular orientation of various polyimides (PIs) and their precursors, poly(amic acid)s (PAAs), were estimated by measuring the visible dichroic absorption at an incidence angle for a rod-like dye (perylenediimide, PEDI) dispersed in the matrices. The effects of PI chain structure, film thickness, heating rate, and residual solvent on a spontaneous in-plane orientation phenomenon were examined to fully understand the mechanism. All PAA films cast on a substrate showed the low degrees of in-plane orientation of the chain axis, nearly independent of the chain structure. Upon thermal imidization of the PAA films adhered on a substrate, a striking spontaneous in-plane orientation behavior was observed for some PI systems with rigid chains; in contrast to that, some flexible PI systems showed no spontaneous behavior. Cure of the PAA films adhered on a substrate induced the spontaneous orientation even if the films were considerably thick (∼50 μm); in contrast to that, the cure of the free-standing thick film did not. However, upon cure of the free-standing thin films (∼10 μm), the spontaneous orientation behavior was observed. For rigid PI systems in which interchain stacking preferentially occurs, thermal cure of the PAA films on a substrate forms liquid-crystal-like highly oriented regions, and simultaneously, apparent stretching (due to constraint of film contraction during imidization) promotes the molecular orientation further. The mechanism is closely associated with a “cooperative effect” in which the neighboring chains enhance the molecular orientation of each other during cure. In addition, structural changes (orientations of the chain axis and a molecular plane and molecular packing) upon stepwise annealing were followed. Polarized infrared absorption spectra measured at an incidence angle demonstrated that the phthalimide molecular plane in the PI film on a silicon wafer aligns somewhat parallel to the film plane, but no significant orientational and conformational changes occurred upon stepwise annealing.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spontaneous Molecular Orientation of Polyimides Induced by Thermal Imidization. 2. In-Plane Orientation

et al. 1996

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“…As oxidation temperature increases, the film density increases giving rise to increase in the adhesion and decreasing the stress. The decrease in stress with increase in temperature is reported by Nomura et al [19] and Kinbara et al [20]. As substrate temperature increases, mobility of adatoms increases and also elimination of trapped excess vacancies occurs which results in increase in adhesion.…”

Section: Discussionmentioning

confidence: 74%

Improvement in the mechanical properties of tin oxide thin films due to vapour chopping

Patil¹,

Puri²,

Puri³

2008

Journal of Alloys and Compounds

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The effect of orientation on thermal expansion behavior in polyimide films

Pottiger

Coburn

Edman

1994

J Polym Sci B Polym Phys

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The anisotropy of the thermal expansion of polyimide films was investigated . Out‐of‐plane or thickness direction coefficients of linear thermal expansion (CTE) were calculated from the difference between the coefficient of volumetric expansion (CVE) and the sum of the in‐plane or film direction coefficients of linear thermal expansion for commercial and spin‐coated PMDA//ODA and BPDA//PPD films and spin coated BTDA//ODA/MPD films. The CVEs were obtained from a pressure‐volume‐temperature (PVT) technique based on Bridgeman bellows. The CVE was shown to be essentially constant, independent of molecular orientation and thickness. A decrease in the in‐plane CTEs therefore occurs at the expense of an increase in the out‐of‐plane CTE. In all cases the calculated out‐of‐plane CTE was higher than the measured in‐plane CTE. The ratio of the out‐of‐plane CTE to the in‐plane CTE was 1.2, 3.8, and 49.3 for the spin‐coated BTDA//ODA/MPD, PMDA//ODA, and BPDA//PPD films, respectively. © 1994 John Wiley & Sons, Inc.

show abstract

Stress in polyimide films having a rodlike molecular skeleton formed on a silicon substrate

Cited by 13 publications

References 9 publications

Spontaneous Molecular Orientation of Polyimides Induced by Thermal Imidization. 2. In-Plane Orientation

Spontaneous Molecular Orientation of Polyimides Induced by Thermal Imidization. 2. In-Plane Orientation

Improvement in the mechanical properties of tin oxide thin films due to vapour chopping

The effect of orientation on thermal expansion behavior in polyimide films

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