This paper describes the design and fabrication of planarized multilayer atom chips for an ultrahigh-vacuum system in atomic physics experiments. A fabrication process is developed to define micrometer-scale wire patterns on a silicon substrate and wires are plated by copper electroplating. SU-8 is chosen as the isolation layer between the upper and bottom wires, and its thickness, surface flatness and surface roughness (Ra = 5 nm) are controlled by the chemical–mechanical planarization process. A reflectivity of nearly 90% is measured on the chip surface; thus, the former method of attaching a silver mirror is unnecessary (Du et al 2004 Phys. Rev. A 70 053606). A heat dissipation copper block is incorporated in our chip design to increase the sustainable current densities of upper wires of more than 3.8 × 105 A cm−2. Results show the improvement of 55.74%, compared with the nonheat dissipation design (2.44 × 105 A cm−2), and thus meeting the requirements for chip-based atom trapping experiments.

This paper describes the development, fabrication and examination of an atom chip through silicon vias (TSV), which is anodically bonded with a Pyrex glass cell to form an ultra-high-vacuum system for the application of Bose-Einstein condensation (BEC) experiments. The silicon via is etched by the inductively coupled plasma reactive ion etch and filled by copper plating technology. The metal wires on both sides of the atom chips are patterned by the lithography process. Three different sizes of TSV are made and tested by continuously applying a maximum current of 17 A under the vacuum (70 Torr) and in air. In addition, after the thermal cycling of an anodic bonding process (requested at 350 • C) and a high electric field of 1000 V m −1 , the TSV on atom chips can still hold the ultra-high vacuum (UHV). The conductive and vacuum yields of the TSV improved from 50% to 100% and from 75% to 81.25%, respectively after the modification of the fabrication process. Finally, the UHV test of TSV on atom chips at room temperature can be reached at 8 × 10 −10 Torr, thus satisfying the requirements of atomic physics experiments under the UHV environment.

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