Organo-soluble Polyimides and Their Applications to Photosensitive Cover Layer Materials in Flexible Printed Circuit Boards

Ishi, Junichi; Sunaga, Tomoyasu; Nomura, Mamiko; Kanaya, Hiroki

doi:10.2494/photopolymer.21.107

Cited by 13 publications

(10 citation statements)

References 7 publications

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“…It was also noted that there was no appreciable effect of the TFMB incorporation on CTE in comparison with the CTE values at lower TFMB contents (CTE = 90 ppm K 21 at TFMB = 0%, and 101 ppm K 21 at TFMB 50%), corresponding to their quite low values of birefringence (n = 0.0015-0.0085) as an indication of the degree of in-plane orientation. The results also mean that for the present rigid PAzM system the solution casting process cannot be a trigger for inducing pronounced in-plane orientation in contrast to the fact that a prominent casting induced in-plane orientation phenomena in some limited soluble PI systems [18,19]. The TFMB50/HFBAPP50 copolymer possessed a relatively low n av -based dielectric constant (3 cal 5 3405) which approximated the directly measured 3 1 value in addition to good film flexibility.…”

Section: Polymerization and Film Properties Of Tpal/tfmb-based Pazmsmentioning

confidence: 63%

Film Properties of Polyazomethines (1). Effect of Incorporation of Intramolecular Cyclodehydrating Units

Ishhii

Ohshima

Tanaka

et al. 2009

High Performance Polymers

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Polyazomethines (PAzMs) were polycondensed from terephthalaldehyde (TPAL) with 2,2′bis(trifluoromethyl)benzidine (TFMB) and 2,2-bis[4-(4-aminophenoxy)phenyl] hexafluoropropane (HFBAPP). The PAzMs showed high solubility in N -methyl-2-pyrrolidone (NMP) ( > 15 wt.%) at room temperature and good film-formability. The film properties of the TPAL/TFMB-based PAzM copolymers were evaluated in the present study. In spite of their rod-like backbone structures, the PAzM films showed much higher coefficients of thermal expansion (CTE) in comparison with initial expectation. The results suggest that the simple casting process from the NMP solutions can not be a trigger for inducing pronounced chain orientation toward the direction parallel to the film plane (in-plane orientation). On the other hand, the incorporation of intramolecular cyclodehydrating (thermally imidizable) sites into the rigid TPAL/TFMB-based PAzM backbone by using pyromellitic dianhydride (PMDA) or 4,4′ -oxydiphthalic anhydride (ODPA) allowed the formation of low-CTE films upon imidization even for rather low reactive site contents. A possible mechanism to explain the present results is proposed. The TPAL/TFMB-based poly(imide-azomethine)s (PIAzMs) achieved excellent combined film properties in addition to low CTE (= 6.7-25.5 ppm K-1); namely, they have relatively high Tg values exceeding 300 °C, very low water absorption ( < 0.17%), sufficient toughness, high tensile modulus, and good thermal stability. Accordingly, the PIAzM systems investigated in the present study could be promising candidates for a new type of heat-resistant dielectric material for use in microelectronic applications.

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Section: Polymerization and Film Properties Of Tpal/tfmb-based Pazmsmentioning

confidence: 63%

Film Properties of Polyazomethines (1). Effect of Incorporation of Intramolecular Cyclodehydrating Units

Ishhii

Ohshima

Tanaka

et al. 2009

High Performance Polymers

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“…Otherwise, significant curling occurs by a CTE mismatch in the laminates. This is a main reason why we have challenged the development of ultra-low-modulus PIs [6][7][8]. However, the molecular designs addressed to ultra-low modulus also give rise to an inevitable serious problem due to a decrease in the content of aromatic units, i.e., a drastic decrease in non-flammability.…”

Section: Low Modulus Pis For CL Filmsmentioning

confidence: 99%

“…approximate to 300 ºC [1], (b) poly(ester imide)s (PEsIs) as FPC base film materials showing low linear coefficients of thermal expansion (CTE) and low linear coefficients of humidity expansion (CHE) [2][3][4][5], and (c) ultra-low-modulus siloxane (or long alkyl chains)-containing PIs as cover layer (CL) materials [6][7][8]. However, in some cases, the molecular designs addressed to the addition of these new functions (low CHE for dimensional stability against moisture absorption and ultra-low-modulus for inhibition of FPC curling, etc.)…”

Section: Introductionmentioning

confidence: 99%

Strategy for Improvement of Non-flammability in Functional Polyimides

Ishii

Yokotsuka

Saito

et al. 2011

J. Photopol. Sci. Technol.

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A phosphorus (P)-containing diamine was synthesized and used as a comonomer at a minor fraction to improve insufficient non-flammability of a poly(ester imide) system as a promising candidate of base film materials in flexible printed circuit boards (FPC). The P-modified PEsI copolymer film displayed the highest level of non-flammability (UL-94, V-0) comparable to commercially available conventional aromatic PI films in addition to original excellent properties, i.e., a very high T g , a low linear coefficient of thermal expansion (15.7 ppm/K) close to copper foils, a low water absorption (0.54 %), a low linear coefficient of humidity expansion (5.53 ppm/RH%), and sufficient toughness (elongation at break = ca. 40%). This approach was also attempted for a very flammable low-modulus PI system for aiming at an application as a coating-type cover layer material in FPC.

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“…In addition, the cover layer coatings formed from the solutions of ultra‐low modulus materials cause no significant curling of FPCs. For this purpose, we have studied solution‐processable ultra‐low modulus PIs including a flexible siloxane block . However, the use of the siloxane‐containing PIs resulted in another serious problem, i.e., interpenetration of a plating solution during a subsequent Ni/Au plating process into the interface between the smooth surface (S‐side) of electro‐deposited copper foil and the cover layer.…”

Section: Introductionmentioning

confidence: 99%

Ultra‐low modulus polyazomethines and enhanced adhesion strength with copper foils

Ishii

Kosugi

Hasegawa

2015

Polymers for Advanced Techs

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Polyazomethines (PAzMs) were prepared from dialdehydes containing different lengths of alkylene groups (m = 2-12) and an ether-containing common aromatic diamine. The main purpose of this work is to achieve an ultra-low modulus and a considerably high adhesion strength with a smooth surface (S-side) of electro-deposited copper foils for applications as novel coating-type protective layer materials of flexible printed circuit boards. The elongation at break of the PAzM films was drastically enhanced by increasing the annealing temperature (T a ). The results are probably attributed to a chain extension effect accompanied with solid-state polymerization promoted at elevated temperatures. An increase in the alkylene chain length (m) led to a gradual decrease in the modulus of the PAzM films owing to an increase in the chain flexibility. It also drastically improved the adhesion strength (S-side); 8.3 N cm -1 at m = 12 in spite of the absence of anchoring effect. To further decrease the modulus, the PAzM (m = 12) was modified with another diamine comonomer containing a polybutylene oxide block. This approach was very effective for achieving the present target properties; the PAzM copolymer displayed ultra-low tensile modulus (0.20 GPa) and a very high adhesion strength (9.8 N cm -1 ) with the S-side of copper foils. a Endothermic peak temperatures determined at a heating rate of 5°C min -1 by differential scanning calorimetry. J. ISHII ET AL.wileyonlinelibrary.com/journal/pat

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Organo-soluble Polyimides and Their Applications to Photosensitive Cover Layer Materials in Flexible Printed Circuit Boards

Cited by 13 publications

References 7 publications

Film Properties of Polyazomethines (1). Effect of Incorporation of Intramolecular Cyclodehydrating Units

Film Properties of Polyazomethines (1). Effect of Incorporation of Intramolecular Cyclodehydrating Units

Strategy for Improvement of Non-flammability in Functional Polyimides

Ultra‐low modulus polyazomethines and enhanced adhesion strength with copper foils

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