2,799 research outputs found
Wafer-Level Parylene Packaging With Integrated RF Electronics for Wireless Retinal Prostheses
This paper presents an embedded chip integration
technology that incorporates silicon housings and flexible
Parylene-based microelectromechanical systems (MEMS) devices.
Accelerated-lifetime soak testing is performed in saline at elevated
temperatures to study the packaging performance of Parylene C
thin films. Experimental results show that the silicon chip under
test is well protected by Parylene, and the lifetime of Parylenecoated
metal at body temperature (37°C) is more than 60 years,
indicating that Parylene C is an excellent structural and packaging
material for biomedical applications. To demonstrate the proposed
packaging technology, a flexible MEMS radio-frequency (RF) coil
has been integrated with an RF identification (RFID) circuit die.
The coil has an inductance of 16 μH with two layers of metal
completely encapsulated in Parylene C, which is microfabricated
using a Parylene–metal–Parylene thin-film technology. The chip
is a commercially available read-only RFID chip with a typical
operating frequency of 125 kHz. The functionality of the embedded
chip has been tested using an RFID reader module in both air
and saline, demonstrating successful power and data transmission
through the MEMS coil
Influence of system integration and packaging on its inductive power link for an integrated wireless neural interface
Journal ArticleIn an integrated wireless neural interface based on the Utah electrode array, the implanted electronics are supplied with power through inductive coupling between two coils. This inductive link is affected by conductive and dielectric materials and media surrounding the implant coil. In this study, the influences of the integration of an implant coil on a silicon-based IC and electrode array, thin-film Parylene-C encapsulation, and physiological medium surrounding the coil were investigated systematically and quantitatively by empirical measurements. A few embodiments of implant coils with different geometrical parameters were made with a diameter of ∼5.5 mm by winding fine wire with a diameter of approximately 50 μm. The parasitic influences affecting the inductive link were empirically investigated by measuring the electrical properties of coils in different configurations and in different media. The distance of power transmission between the transmit and receive coils was measured when the receive coil was in air and immersed in phosphate buffered saline solution to simulate an implanted physiological environment. The results from this study quantitatively address the influences of factors such as device integration, encapsulation, and implantation on its inductive power link, and suggest how to maximize the efficiency in power transmission for such neural interface devices powered inductively
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