Scaling toward Diminutive MEMS: Dust‐Sized Spray Chips for Aerosolized Drug Delivery to the Lung

Abstract The functional area of silicon‐based microelectromechanical systems (MEMS) devices often occupies only a fraction of the actual silicon area of the chip. As the chip cost directly scales with the total chip area, there is an incentive to reduce the chip to the smallest possible size. However, handling such diminutive devices poses challenges that industry‐standard packaging cannot solve. Here, the world's smallest spray nozzle chip for drug delivery to the lung is manufactured and packaged and how magnetic assembly combined with microfluidic glue fixation can overcome this barrier for diminutive MEMS devices is demonstrated. The spray nozzle chips have a circular footprint with a diameter of 280 µm and feature a nickel coating on their conical sidewall, allowing magnetic manipulation. The chips are assembled and sealed into plastic substrates using a three‐step gluing process guided by capillary action and activated by heat. Assembly speeds of up to 147 chips per minute are demonstrated and fabrication to packaging and functional operation of this device is shown for the target application.