Injection Compression Molding of LDS-MID for Millimeter Wave Applications

Abstract

LDS-MIDs (laser direct structured mechatronic integrated devices) are 3D (three-dimensional) circuit carriers that are used in many applications with a focus on antennas. However, thanks to the rising frequencies of HF (high-frequency) systems in 5G and radar applications up to the mmWave (millimeter wave) region, the requirements regarding the geometrical accuracy and minimal wall thicknesses for proper signal propagation in mmWave circuits became more strict. Additionally, interest in combining those with 3D microstructures like trenches or bumps for optimizing transmission lines and subsequent mounting processes is rising. The change from IM (injection molding) to ICM (injection compression molding) could offer a solution for improving the 3D geometries of LDS-MIDs. To enhance the scientific insight into this process variant, this paper reports on the manufacturing of LDS-MIDs for mmWave applications. Measurements of the warpage, homogeneity of local wall thicknesses, and replication accuracy of different trenches and bumps for mounting purposes are presented. Additionally, the effect of a change in the manufacturing process from IM to ICM regarding the dielectric properties of the used thermoplastics is reported as well as the influence of ICM on the properties of LDS metallization—in particular the metallization roughness and adhesion strength. This paper is then concluded by reporting on the HF performance of CPWs (coplanar waveguides) on LDS-MIDs in comparison to an HF-PCB.

Dielectric Properties of PEEK/PEI Blends as Substrate Material in High-Frequency Circuit Board Applications

“…To achieve the latter, integration of conductive tracks into already highly integrated devices (MID: Molded Interconnect/Mechatronic Integrated Devices) via laser structuring and metallization is already established. First investigations have already been carried out to test the applicability of these materials for the high-frequency (HF) range [ 2 ]. However, with rising signal frequencies, the signal dampening properties of the PCB substrate material become more and more important, as shorter electromagnetic wave lengths in the relevant GHz regime become increasingly prone to absorption in matter [ 3 , 4 ].…”