For long-term performance, chronically implanted brain probes need to be further reduced in size with a low mechanical mismatch to meet that of the surrounding neural tissue. However, the fabrication of these complaint devices has brought up insertion issues due to the lack of rigidity that brings additional complications in assembling and surgery. To address this challenge, this paper reports a novel and versatile batch fabrication approach to deliver ultra-thin and flexible penetrating probes utilizing biodegradable and programmable sacrificial layers. The innovative and yet robust batch fabrication technology allows complete design freedom of the neural probe in terms of materials, size, shape and stiffness. These results provide a novel technological solution for implanting flexible and ultrathin devices, which possesses great potential for brain research.