Abstract
This paper reports the theoretical and experimental studies of high-Q suspended microinductors produced by flip-chip assembly for multigigahertz RF integrated-circuit applications. The effects of device and substrate parameters on the Q factor of the inductor devices are studied by numerical simulation using Ansoft's High Frequency Structure Simulator electromagnetic field simulation package. Suspended inductor devices are realized using a flip-chip assembly method in which the inductor structures with the supporting pillars are fabricated on a low-cost polyimide thin-film carrier and then assembled onto a low resistivity (3-4 O · cm) silicon substrate by flip-chip bonding. Individual and 2 × 2 arrays of meander and spiral inductor designs have been successfully fabricated with air gap heights ranging from 15 to 31 µm. Maximum Q factors of ~15 and ~13 at ~1 GHz have been achieved for meander and spiral suspended inductor devices before pad deembedding. It is shown that the optimal air gap between the inductor and substrate surface is ~15 µm beyond which no further enhancement in the Q factor can be obtained for devices on low-resistivity substrates. The experimental results are in excellent agreement with that of theoretical simulation. The inductor assembly method requires minimal chip/wafer processing for integration of high-Q inductors. © 2007 IEEE.
Original language | English |
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Pages (from-to) | 1171-1181 |
Number of pages | 11 |
Journal | IEEE Transactions on Microwave Theory and Techniques |
Volume | 55 |
Issue number | 6 |
DOIs | |
Publication status | Published - Jun 2007 |
Keywords
- Flip-chip assembly
- High Q
- Microelectromechanical systems (MEMS)
- Modeling
- Passive inductor
- Polyimide film
- Silicon RF integrated circuit (RFIC)