Low Df Polyimide with Photosensitivity for High Frequency Applications

Abstract

We have investigated molecular motion and polarity of polyimide chain to developed novel low dielectric constant (Dk) and dissipation factor (Df) polyimides. We found that Df at 10-100 GHz corresponds molecular mobility at-150 to-50 ℃. To reduce the dielectric loss (=Df) at high frequency, restriction of molecular motion at low temperature was important. In addition, to reduce polar and flexible unit in the polyimide chain is also important to obtain low Dk and Df polyimide. We exploited these knowledge for development of low dielectric loss polyimide for RDL. As the result, we achieved 0.002 of loss tangent and 2.7 of dielectric constant respectively about novel polyimide. Those polyimides are patternable by alkaline wet etching with positive photo-resist development and by UV laser ablation method. We also have developed photo-definable low loss tangent polyimide by blending of photo active reagent. Lower insertion loss of microstrip line was observed by the novel low Df polyimide than by conventional photosensitive polyimide. Those low dielectric loss polyimides are suitable for insulator of FO-WLP, interposer and other RF applications for microelectronics.

Development of A Phenolic Resin-Based Material with Low Coefficient of Thermal Expansion Patternable by Laser Ablation

“…Compared to photolithography, laser ablation has advantages such as no need of the consideration of photoreaction-induced solubility change, leading to simplicity of material design and no need of development processes, leading to the reduction of costs for developing fluid and equipment and the reduction of the environmental load derived from waste solutions. So far, as examples of applying laser ablation to resin materials, various resin compositions have been reported [15][16][17][18][19]. Some of these were applied as interlayer insulating films between redistribution layers.…”

A Method for Broadband Polyimide Permittivity Measurement of Silicon Interposer Applied for High Speed Digital Microsystem

“…Different dopants and preparation procedures will result in different Dk values for Polyimide. As listed in Table 1 , the Dk value of Polyimide is generally distributed within 2.2 to 3.2 [ 21 , 22 , 23 , 24 , 25 ]. In the experiment of this paper, when the accuracy is set to 0.1, the Dk value retrieved by the algorithm is distributed within the range of 2.680 to 4.500, which proves the reliability of the range retrieval algorithm and the initial range suitable for iterative inversion is determined.…”

Polyimides for Micro-electronics Applications

“…It has been used because of its low dielectric loss, but there are also problems such as low adhesiveness, and low dielectric constant and low dielectric loss are being studied by making porous polyimide [79]. Authors obtain a low dielectric loss photosensitive polyimide design guide line by dynamic mechanical analysis [80].…”