SAW filter

DennyT

工作上真的需要就花錢買來看看吧:
0 m2 z. l$ R' x7 M! a3 w; b用PCB取代HTCC (高溫共燒陶瓷) 基板, 不過好像不是直接用銅箔蝕刻SAW, 因為它還是用了鉭酸鋰wafer及薄膜製程來構成SAW本體, 只是封裝結構捨棄HTCC, 直接mount在PCB上.

直接用銅箔及FR4做成SAW應該沒辦法上到GHz吧, 看看PCB銅線蝕刻最小mm級pitch對上半導體製程的um或sub-um pitch, FR4 SAW能有百KHz就很厲害了吧, 上到MHz便可稱神人了.
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http://ieeexplore.ieee.org/Xplor ... +Im%3B+Seunghee+Lee
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Development of the RF SAW filters based on PCB substrate
Youngjin Lee; Jongin Im; Seunghee Lee
5 y5 U' l- a4 J) d( `: jInternational Frequency Control Symposium and Exposition, 2006 IEEE
Volume , Issue , June 2006 Page(s):334 - 337
& A4 W/ J9 s2 c# |5 tDigital Object Identifier   10.1109/FREQ.2006.275408
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Summary: Recently produced RF SAW (surface acoustic wave) filters are made using HTCC (high temperature cofired ceramic) with CSP (chip scale package) technology. This paper describes the development of a new 1.4 times 1.1 and 2.0 times 1.4 mm RF SAW filter based on PCB (printed circuit board) substrate instead of HTCC package, which reduces the cost of materials by 40%. We have investigated the multilayered PCB substrate structure and raw materials to determine the optimal flip-bonding condition between the LiTaO3 wafer and PCB substrates. Also, optimal materials and processing conditions for the epoxy laminating film were experimentally determined that can reduce the bending moment caused by thermal expansion differences between the PCB substrate and laminating film. The new PCB SAW filter shows better electrical and reliability performances than those observed with present SAW filters.