The subject matter disclosed herein generally relates to cold spray systems, and more specifically to an apparatus and a method for operating a micro cold spray system.
Advancements in electronic and sensor systems require high performance materials and fabrication methods that permit manufacturing of optimized designs. This requires further miniaturization and integration, while enhancing the functionality and lifetime of existing systems. New strategies in materials formulation and device fabrication are needed in order to eliminate the long lead times required for the fabrication of prototypes and evaluation of new materials and designs. Direct Write (DW) techniques, which do not need photolithographic work, support rapid prototyping, development and testing of new multifunctional materials. DW techniques are complementary to photolithography techniques, allowing for conformal patterning and rapid turnaround.
Micro Cold Spray (MCS) is a variant of both bulk cold spray and aerosol DW which utilizes the cold spray process to deposit fine conductive features for microelectronic applications. MCS differs from cold spray in the types of targeted applications and feature sizes, and differs from aerosol-based DW in the deposition process. The MCS technique is capable of operating at room temperature in air while maintaining sub-mm resolution and does not require post processing such as thermal annealing.
Due to the nature of the cold deposition mechanism, when compared with thermal spray or laser-based processes, MCS offers relatively low oxide content, significantly reduced or elimination of thermally induced stresses, and the ability to coat a variety of substrates, including polymers. However, there are existing challenges associated with MCS printing which include: (1) relatively high operating costs due to the use of expensive gases like helium, (2) reduced bond strength and density for hard materials, such as Titanium alloys, and (3) large compressive residual stresses attributed to the extremely short timescales available for bonding.