Low Dk and Df Photosensitive Insulation Material for Low Transmission Loss Packages

Abe, Shin‐ichiro; Mitsukura, Kazuyuki; Imazu, Yuki; Toba, Masaya; Masuko, Takashi; Kurafuchi, Kazuhiko

doi:10.4071/2380-4505-2018.1.000415

Cited by 6 publications

(1 citation statement)

References 3 publications

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“…Dielectric properties of the copolymers and their moisture absorption behavior under the 85 °C/85 RH condition are plotted in Figure a,b, respectively. Not only are these parameters essential for EMC applicationswhere the dielectric properties impact the signal delay and transmission loss and moisture absorption greatly influences the package reliability during solder reflow, thermal shock, or thermal cycling conditions where the escaping vapor causes cracking or bubbling (“popcorn crack”)but also they together provide useful insights into the internal material structures. When increasing the NCE concentration, the D k initially decreased until it reached a 1:1 ratio, where further charging NCE monomers in the feed caused a reversed effect in D k .…”

Section: Results and Discussionmentioning

confidence: 99%

Melt Processable Novolac Cyanate Ester/Biphenyl Epoxy Copolymer Series with Ultrahigh Glass-Transition Temperature

Ren

Sun

et al. 2021

ACS Appl. Mater. Interfaces

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The rapid progress in silicon carbide (SiC)-based technology for high-power applications expects an increasing operation temperature (up to 250 °C) and awaits reliable packaging materials to unleash their full power. Epoxy-based encapsulant materials failed to provide satisfactory protection under such high temperatures due to the intrinsic weakness of epoxy resins, despite their unmatched good adhesion and processability. Herein, we report a series of copolymers made by melt blending novolac cyanate ester and tetramethylbiphenyl epoxy (NCE/EP) that have demonstrated much superior hightemperature stability over current epoxies. Benefited from the aromatic, rigid backbone and the highly functional nature of the monomers, the highest values achieved for the copolymers are as follows: glass-transition temperature (T g ) above 300 °C, decomposition onset above 400 °C, and char yield above 45% at 800 °C, which are among the highest of the known epoxy chemistry by far. Moreover, the high-temperature aging (250 °C) experiments showed much reduced mass loss of these copolymers compared to the traditional high-temperature epoxy and even the pure NCE in the long term by suppressing hydrolysis degradation mechanisms. The copolymer composition, i.e., NCE to EP ratio, has found to have profound impacts on the resin flowability, thermomechanical properties, moisture absorption, and dielectric properties, which are discussed in this paper with in-depth analysis on their structure−property relationships. The outstanding high-temperature stability, preferred and adjustable processability, and the dielectric properties of the reported NCE/EP copolymers will greatly stimulate further research to formulating robust epoxy molding compounds (EMCs) or underfill for packaging next-generation high-power electronics.

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Section: Results and Discussionmentioning

confidence: 99%

Melt Processable Novolac Cyanate Ester/Biphenyl Epoxy Copolymer Series with Ultrahigh Glass-Transition Temperature

Ren

Sun

et al. 2021

ACS Appl. Mater. Interfaces

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Development of Low Dk and Df polyimides for 5G application

Matsukawa

Nagami

Mizuno

et al. 2019

International Symposium on Microelectronics

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We have newly developed non photosensitive and photosensitive polyimide having excellent electrical/mechanical properties. At first we have re-designed the polymer backbone in order to obtain low Dk and Df performance. As a result, our new non photosensitive PI achieved 2.9 of Dk at 20 GHz and 0.003 of Df at 20 GHz. In the next step, we selected the photo package of new PI carefully to maintain both low Dk/Df and high resolution. After that, we modified the photo initiator content, crosslinker content, and so on to have both high lithographic performance and high electrical performance. As a result, new photosentive PI cured at 320 °C showed 3.0 of Dk at 20 GHz and 0.006 of Df at 20 GHz. In addition, this material cured at 200 °C also showed 3.0 of Dk at 20 GHz and 0.009 of Df at 20 GHz. We also confirmed high mechanical properties of new PI. Elongation of this PI cured at >250 °C was approximately 70 %. From lithographic aspects, new PI achieved 15 μm L/S opening with 10 μm thickness.

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Semi-additive Process Based Cu Wirings with Ultra Smooth Electroless Cu Seed Layer and Important Factor for High Frequency Transmission Property

Toba

Nomoto

Komuro

et al. 2019

International Symposium on Microelectronics

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Semiconductor packages for high performance devices with printed circuit boards having multi wiring layers such as FC-BGA have been attracting the attention in order to realize ultra-reliable and low latency communications in 5G networking. Cu wirings for the package are usually fabricated by via formation by laser for dielectric, desmear, electroless Cu seed formation, photoresist patterning, electrolytic Cu plating, resist stripping and seed layer etching. Though a desmear process can obtain enough adhesion between dielectric and Cu seed layer by anchoring effect to secure reliabilities, the interface between dielectric and Cu seed layer should be smooth to achieve low attenuation of electric signals at high frequencies. Here, instead of a desmear process, we applied an UV modification for the surface of dielectric in order to realize a smooth and high adhesive seed layer against dielectric. We obtained 0.8 kN/m of peel strength between dielectric and Cu seed layer in spite of surface roughness (Ra) of dielectric was 45 nm by nano-level anchoring effect at UV modified layer. Due to the smooth interface by UV modification, S21 value of microstrip line was 26 % improved compared to that assembled through desmear process at 60 GHz.

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Low Dk and Df Photosensitive Insulation Material for Low Transmission Loss Packages

Cited by 6 publications

References 3 publications

Melt Processable Novolac Cyanate Ester/Biphenyl Epoxy Copolymer Series with Ultrahigh Glass-Transition Temperature

Melt Processable Novolac Cyanate Ester/Biphenyl Epoxy Copolymer Series with Ultrahigh Glass-Transition Temperature

Development of Low Dk and Df polyimides for 5G application

Semi-additive Process Based Cu Wirings with Ultra Smooth Electroless Cu Seed Layer and Important Factor for High Frequency Transmission Property

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