The detection of rare events requires transmitting the extremely weak signal, in which electronic substrates with low background levels and strong binding forces are extremely important. Polytetrafluoroethylene (PTFE) and its homologue poly (perfluoroethylene, FEP) are excellent low background and high dielectric layers in electronic substrates widely applicated in rare event detection experiments. For JFET to transmit and amplify weak signals, they are usually positioned very close to the detector. Therefore, electronic substrates are required to be screened out to have low background levels, good adhesion and low-temperature resistance to meet the requirements of rare event detection experiments.
Surface modification of dielectric layers with PTFE and FEP is carried out by ion implantation, to solve the problem of difficult metallization between polymer and metal layers of electronic substrates. The Stopping and Range of Ions in Matter (SRIM) simulation is used to analyze the implantation depth and ion distribution of the surface. A transition layer and electrolytic copper are deposited on the polymer by the filtered cathode vacuum arc and electrochemical methods, respectively. The morphology, active groups and valence bonds are evaluated to determine the microstructure characteristics. Correspondingly, the mainly adhesion mechanism between copper and the dielectric is explained by mechanical anchoring physical action, chemical bonding and intermolecular forces. Furthermore, γ-ray background of electronic substrates prepared by us is relatively lower than common commercial devices.
We offer a new method to fabricate the direct surface metallization of perfluorinated polymers. The surface modification of polymer is to obtain electronic substrates with low background levels and low-temperature resistance, which has good electrical performance, and is also applied to China Dark matter EXperiment tests.