FCC-ee vertex detector R&D workshop

R&D on flexible and low mass packaging for high-frequency communication of future MAPS detectors

Not scheduled

20m

Sala Galilei - Room 131 (ground floor) (INFN Pisa)

Speaker

Dr David Novel (Fondazione Bruno Kessler)

Description

Minimizing the detector material budget to ≲ 0.3% of a radiation length X0 is one of the key challenges in building future experiments such as FCC-ee. A major obstacle to achieving this goal often lies not in the sensor itself, but in the FPC and the associated mechanical supports.
Another critical requirement for future experiments is the transmission of high data rates, driven by the advent of the new 65 nm MAPS sensors, where digital communication speeds of up to 10 Gbps are expected. The need for ultra-thin FPCs becomes even more pressing when considering complex, bent sensor geometries to enable hermetic coverage of the beam pipe, as in the ALICE IT3 now under construction.
Balancing the requirements of FPC design - high data rate transmission, low material budget and high mechanical flexibility - is a challenge.
Ensuring signal integrity for high-speed communication typically requires thick FPCs to achieve proper impedance matching, which directly conflicts with material budget constraints. Standard FPC-based interconnects are therefore incompatible with the stringent requirements of inner tracking systems.
To address this, Fondazione Bruno Kessler (FBK) initiated a dedicated technological platform a few years ago, focusing on the microfabrication of low-material-budget flexible FPCs for integrating next-generation MAPS detectors into future vertex detectors. The basic idea of the presented approach stands on leveraging advanced microfabrication methods inherited from FBK silicon detector production ensuring precise feature control and, consequently, excellent signal integrity.
In this work, we present a prototype integrating an ALPIDE chip on a two-layer flexible FPC made of kapton-aluminum as substrate, with a total material budget of ~0.1% of X0 (about 0.05% sensor + 0.05% FPC). The prototype demonstrates both feasibility and reliable signal transmission along differential lines.
The complete workflow - from material selection, design and microfabrication, to bonding and characterization - has been developed at FBK and will be described in detail. We also discuss the broader applicability of this technology in detector design, including compatibility with key techniques such as different sensor bonding, passive component integration, and FPC vias.