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RF tuning by wirebond inductance on thin packages

IP.com Disclosure Number: IPCOM000234579D
Publication Date: 2014-Jan-20
Document File: 2 page(s) / 40K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to tune the wirebond inductance for thin packages. This method uses a dummy pad next to an active pad to tune wirebond inductance.

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RF tuning by wirebond inductance on thin packages

The performance of radio frequency (RF) devices is sensitive to wiring inductance.

Although inductance can be detrimental to device performance, for some circuits (e.g.,

an impedance inverter), additional inductance is beneficial [1]. Wirebonds can be used to achieve the desired inductance. The inductance of the wirebond depends on the thickness of the wire, the length, and the shape.

For thick packages, tuning of the wirebond inductance can be achieved by adjusting the

wirebond height. This changes the length and, hence, the inductance of the wirebond. However, for thin packages, the wirebond loop height must be minimized (by using a stand-off-stitch bond) [2], so it is not possible to adjust the wirebond loop height to tune the inductance. Hence, another method is required to tune the wirebond inductance for thin packages.

Figure 1: Conventional wirebond; loop height is good for inductance tuning, but too high for thin packages

The novel contribution is a method that uses a dummy pad next to an active pad to tune

wirebond inductance. A first wirebond (1) is made from the die (7) to the dummy pad


(9), using a stand-off-stitch bond, to minimize wirebond loop height (i.e., for compatibility with a thin package). Then, a second wirebond (10) is made from the dummy pad to an active pad (15). The loop height of the second wirebond can be adjusted to tune inductance, while still maintaining a small loop height so that...