6 October 2017 A self-assembly optimization method for BAW filter layout design
Author Affiliations +
In order to reduce the volume of the filter and increase the number of chips on the wafer, while ensure the filter performance, a design method of the bulk acoustic wave (BAW) ladder filter is proposed. This layout design method consists of 11 design criteria and a 6-step flow. The 11 design criteria limit the shape and position of the BAW resonators (BAWRs), the distance between the BAWRs, the distance between the BAWRs and the pads and the interconnecting wire. The layout design flow has 6 steps. 1) Preset the shape of each BAWR (square/pentagon) according to its active area values. 2) Add an auxiliary circumcircle for each BAWR, tightly align all the series resonator circumcircles along a central line in order, and mate the corresponding electronically neighboring parallel resonator circumcircles one by one at a position above/below the center line. This makes an initial 3-row and n-column 2D arrangement, and the column number N is determined by the filter order. 3) Fix the very first series resonator circumcircle position and incrementally “compress” the initially self-assembled 3-row structure along the row width direction until the row height for row width bargain is no more cost effective. 4) Apodize the square series resonators and fine-tune each resonator’s shape and rotation according to above-mentioned related design criteria. 5) Wiring BAWRs and pads together. 6) A combined acoustic-electromagnetic BAW filter simulation method is used to validate the layout result. In a 5-order BAW ladder filter layout demo case, a layout fill ratio over 44% is obtained. An auto-layout program “BAW-filter Auto-layout Tool (BAT®)” based on the presented method is also presented.
Conference Presentation
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Yang Gao, Yang Gao, Da-Peng Zhang, Da-Peng Zhang, Le Jia, Le Jia, Shu-Wen Wen, Shu-Wen Wen, } "A self-assembly optimization method for BAW filter layout design", Proc. SPIE 10438, Emerging Imaging and Sensing Technologies for Security and Defence II, 104380A (6 October 2017); doi: 10.1117/12.2278209; https://doi.org/10.1117/12.2278209

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