本研究主要分析薄膜體聲波諧振器(thin film bulk acoustic wave resonator,FBAR)及濾波器頻寬改善之方法，方法是以二次濺鍍法配合光罩的設計來沉積二或三種不同上電極厚度的FBAR元件於同一試片上，目的為做出具有不同諧振頻率之諧振器，進而完成改善濾波器頻寬之研究。FBAR元件採用背向蝕刻結構的FBAR元件，而FBAR的結構為在矽基板上沉積下電極鉑、壓電層氮化鋁、上電極鋁而背面的空腔採用ICP乾式蝕刻，蝕刻遮罩使用200nm的Al，而其中Al上電極是由射頻磁控濺鍍機沉積而成，所謂兩次濺鍍法即是藉由光罩的設計讓兩次濺鍍時分別把上電極濺鍍在同一試片但是不同的FBAR元件上，又因為兩次濺鍍的時間不同故可以達到濺鍍出不同上電極厚度的目的。
在製作FBAR元件的過程中，由於在製程上遇到重重困難故最後沒能成功做出FABR元件，但在方法上成功的在同一試片上做出不同上電極厚度的FBAR元件。而在製作的過程中遇到的困難有下電極鉑附著性問題、壓電層氮化鋁濕蝕刻問題、上電極斷裂問題與ICP蝕刻問題，本研究探討這些問題發生的原因，並針對這些問題提出改善與解決的辦法，希望能幫助未來在製作FBAR元件時能夠解決製程上的問題並提升製做良率。

In this thesis, two or more than two different thicknesses of the top electrode were deposited for FBARs by using double electrode-growing method. In addition, difficulties and improvement on the fabricating process would also discussed. The experimental results showed that the deposition rate of AlN and Al electrode greatly depended on the surface condition of the Al target, lower rate resulting from cracked surface due to long history of usage. Trouble was found with the peeling-off of Pt thin film. To solve the problem, the method of reducing evaporation rate of Pt with enhanced thickness of adhesive layer was propased. During the process of wet etching with H3PO4, some part of AlN piezoelectric layer under the photoresist was unexpectedly etched away. The solution is to perform the etching in two steps concecutively. Each step has its own photoresist and less etching time. In addition, to prevent the cut off of Al top electrode, it is recomanded to keep the FBAR chip from contact with the beaker, such as the bottom of the beaker with the acetone solution, during the ultrasonic vibration of lift-off process. Finally, during the ICP etching process, poor adhesion of the Al mask film and shallow etching depth of Si substrate happened. The solution was to enhance the adhesion of Al by reducing Al evaporation rate for the mask or using tantalum nitride as the alternative mask material.

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