JP3643497B2

JP3643497B2 - Method for manufacturing surface acoustic wave device

Info

Publication number: JP3643497B2
Application number: JP06433899A
Authority: JP
Inventors: 浩清水; 圭一中西
Original assignee: Toko Inc
Current assignee: Toko Inc
Priority date: 1999-03-11
Filing date: 1999-03-11
Publication date: 2005-04-27
Anticipated expiration: 2019-03-11
Also published as: JP2000261268A

Description

【０００１】
【発明の属する技術分野】
本発明は、表面弾性波素子の製造方法に係るもので、特に、素子による周波数のばらつきを補正するための周波数調整方法に関するものである。
【０００２】
【従来の技術】
表面弾性波素子の製造にあたっては、1枚のウェハに複数の素子が形成される。しかし、ウェハごとに製造条件や材料の特性等の問題から、設計値通りの特性が得られないことが多い。また、通常ウェハは面内で製造ばらつきに起因する周波数分布を有しており、面内のばらつきよりも規格幅が狭い場合には製品の歩留まりが低下する。
【０００３】
それに対処する方法として、ウェハ単位ではなく素子単位で周波数調整を行うこともできるが、非常に小さい素子であるので取り扱いが困難であり、処理の効率が極めて低くなってしまう。
【０００４】
【発明が解決しようとする課題】
本発明は、素子の取り扱いを容易にするとともに、複数の素子を一括して処理し、複数の素子を同時に周波数調整できるようにして、処理の効率を高めるものである。また、周波数調整を精度よく、かつ、自動的に行うものである。
【０００５】
【課題を解決する手段】
本発明は、表面弾性波素子の共振周波数をウェハ状態で測定し、ダイシングの後に同じ特性の素子をまとめてエッチング処理することによって、上記の課題を解決するものである。
【０００６】
すなわち、表面弾性波素子の周波数を測定し、周波数のずれに応じて素子の周波数調整を行う表面弾性波素子の製造方法において、ウェハの状態でウェハ内の個々の素子の周波数を測定した後、ウェハをダイシングして個々の素子に分割し、同じ周波数帯の素子に分類し、同じ周波数帯の複数の素子を固定し、それらの素子の電極表面の酸化膜をエッチングして除去し、更に所定時間電極膜をエッチングしてそれらの素子を一括して周波数調整を行うことに特徴を有するものである。酸化膜の除去はウェハの状態で行ってもよい。
【０００７】
【発明の実施の形態】
本発明の工程を、図１を参照して、説明する。水晶等の圧電性基板上にフォトリソグラフィー技術によって、アルミニウム等の電極を具えた表面弾性波素子を多数形成し、それらの素子の共振周波数をウェハのままの状態で測定する。
【０００８】
測定結果を記録しておき、ダイシングを行って個々の素子に分割する。その際に、ウェハ状態で測定された共振周波数に応じて素子が分類され、同じ周波数帯の素子が集められる。ここで、各周波数帯の素子の周波数のずれの状態に応じて調整する周波数に基づいて、エッチング処理の時間が算出される。
【０００９】
集められた同じ周波数帯の表面弾性波素子は、処理のために例えばテープによってプレートに配列して固定され、その状態で酸あるいはアルカリ溶液中で処理される。通常、電極膜の質量を変えることによって周波数の調整を行うが、電極膜のエッチングあるいは陽極酸化等を行うためである。
【００１０】
【実施例】
本発明においては、多数の表面弾性波素子が形成されたウェハの状態で各素子の周波数を測定する。周波数の測定は各素子の電極にプローブ針を当てて共振周波数を測定する。測定した結果は、その素子の位置のデータとともに記録される。ウェハがダイシングされて各素子に分離されるときに、そのデータに従って同じ周波数帯の素子に分類される。
【００１１】
個々の素子のままでは取り扱いが困難で処理の効率が悪くなるので、同じ周波数帯の素子を整列させて固定することが必要となる。そこで、表面弾性波素子をテープによってプレートに貼り付けるとよい。このプレートを酸あるいはアルカリ溶液に浸して処理することによって、周波数の調整をすることができる。もともと同じ周波数帯の素子の集まりであるので、同じ条件で処理すれば同じ幅で周波数の調整ができる。なお、各素子をトレーに収納して保持してもよい。
【００１２】
本発明においては、電極膜の化学的処理による周波数の調整の前に、電極膜を覆う表面の酸化膜の除去のためのエッチングを行う。このエッチングは、電極膜自体のエッチングに先立って行うもので、電極膜の処理時間に加えて酸化膜の除去に必要な時間をセットすることによって制御する。これによって、図２に示したように、酸化膜除去のための一定時間経過後に電極膜の処理が始まって周波数調整が行われる。なお、酸化膜の除去の工程はダイシングの前としてもよい。電極膜のエッチングは、目的の周波数からの周波数の偏差と予め実験で求めたエッチング時間による周波数変化量との相関関係から時間を決めて行う。
【００１３】
【発明の効果】
本発明によれば、ウェハの状態で共振周波数を測定するので機械化、自動化が容易であるし、素子の周波数の調整は複数個を一括して同一条件で処理することができる。したがって、処理の効率を大幅に向上させることができる。
【００１４】
また、小さなチップをまとめて固定して処理するので、取り扱いを容易にする利点もある。
【図面の簡単な説明】
【図１】本発明の工程のブロック図
【図２】本発明の処理の説明図[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a surface acoustic wave device, and more particularly to a frequency adjustment method for correcting frequency variations due to the device.
[0002]
[Prior art]
In manufacturing a surface acoustic wave device, a plurality of devices are formed on a single wafer. However, due to problems such as manufacturing conditions and material characteristics for each wafer, characteristics as designed values are often not obtained. In addition, a normal wafer has a frequency distribution due to manufacturing variations in the plane, and the product yield decreases when the standard width is narrower than the in-plane variations.
[0003]
As a method for dealing with this, it is possible to adjust the frequency not in units of wafers but in units of elements. However, since they are very small elements, they are difficult to handle and the processing efficiency is extremely low.
[0004]
[Problems to be solved by the invention]
The present invention facilitates the handling of the elements, processes a plurality of elements at once, and adjusts the frequency of the plurality of elements at the same time, thereby improving the processing efficiency. Further, the frequency adjustment is performed automatically with high accuracy.
[0005]
[Means for solving the problems]
The present invention solves the above-mentioned problems by measuring the resonance frequency of a surface acoustic wave device in a wafer state and collectively etching the devices having the same characteristics after dicing.
[0006]
That is, after measuring the frequency of the surface acoustic wave element and measuring the frequency of each element in the wafer in the state of the wafer in the surface acoustic wave element manufacturing method for adjusting the frequency of the element according to the frequency deviation, The wafer is diced and divided into individual elements, classified into elements of the same frequency band, a plurality of elements of the same frequency band are fixed, the oxide film on the electrode surface of those elements is removed by etching, and further predetermined This is characterized in that the time electrode film is etched to collectively adjust the frequency of these elements. The removal of the oxide film may be performed in a wafer state.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The process of the present invention will be described with reference to FIG. A large number of surface acoustic wave elements having electrodes such as aluminum are formed on a piezoelectric substrate such as quartz by photolithography, and the resonance frequencies of these elements are measured as they are on the wafer.
[0008]
The measurement results are recorded, and dicing is performed to divide each element. At that time, the elements are classified according to the resonance frequency measured in the wafer state, and the elements in the same frequency band are collected. Here, the etching process time is calculated based on the frequency adjusted according to the frequency shift state of the elements in each frequency band.
[0009]
The collected surface acoustic wave elements of the same frequency band are arranged and fixed on a plate by, for example, tape for processing, and processed in an acid or alkali solution in that state. Usually, the frequency is adjusted by changing the mass of the electrode film in order to perform etching or anodic oxidation of the electrode film.
[0010]
【Example】
In the present invention, the frequency of each element is measured in the state of a wafer on which a number of surface acoustic wave elements are formed. The frequency is measured by applying a probe needle to the electrode of each element and measuring the resonance frequency. The measurement result is recorded together with the position data of the element. When the wafer is diced and separated into each element, it is classified into elements of the same frequency band according to the data.
[0011]
Since it is difficult to handle individual elements as they are and processing efficiency is deteriorated, it is necessary to align and fix elements in the same frequency band. Therefore, the surface acoustic wave element may be attached to the plate with a tape. The frequency can be adjusted by immersing the plate in an acid or alkaline solution. Since this is originally a collection of elements in the same frequency band, the frequency can be adjusted with the same width if processed under the same conditions. Each element may be stored and held in a tray.
[0012]
In the present invention, etching for removing the oxide film on the surface covering the electrode film is performed before adjusting the frequency by chemical treatment of the electrode film. This etching is performed prior to the etching of the electrode film itself, and is controlled by setting the time necessary for removing the oxide film in addition to the processing time of the electrode film. As a result, as shown in FIG. 2, the processing of the electrode film starts after a predetermined time for removing the oxide film, and the frequency is adjusted. Note that the step of removing the oxide film may be performed before dicing. The etching of the electrode film is performed by determining the time from the correlation between the frequency deviation from the target frequency and the amount of frequency change due to the etching time obtained in advance by experiments.
[0013]
【The invention's effect】
According to the present invention, since the resonance frequency is measured in the state of the wafer, it is easy to mechanize and automate, and the adjustment of the frequency of the elements can be performed in batches under the same conditions. Therefore, the processing efficiency can be greatly improved.
[0014]
In addition, since small chips are collectively fixed and processed, there is an advantage that handling is easy.
[Brief description of the drawings]
FIG. 1 is a block diagram of the process of the present invention. FIG. 2 is an explanatory diagram of the process of the present invention.

Claims

In the method of manufacturing a surface acoustic wave device that measures the frequency of the surface acoustic wave device and adjusts the frequency of the device according to the frequency shift, after measuring the frequency of each device in the wafer in the state of the wafer, Dicing and dividing into individual elements, classifying them into elements of the same frequency band, fixing a plurality of elements of the same frequency band, etching and removing the oxide film on the electrode surface of those elements, and further electrode for a predetermined time A method of manufacturing a surface acoustic wave device, comprising etching a film and performing frequency adjustment of the devices collectively.

In the method of manufacturing a surface acoustic wave device that measures the frequency of the surface acoustic wave device and adjusts the frequency of the device according to the frequency shift, after measuring the frequency of each device in the wafer in the state of the wafer, The oxide film on the electrode surface of the element is removed by etching, the wafer is diced and divided into individual elements, classified into elements of the same frequency band, a plurality of elements of the same frequency band are fixed, and the electrode is further applied for a predetermined time. A method of manufacturing a surface acoustic wave device, comprising etching a film and adjusting the frequency of the devices collectively.

In the method of manufacturing a surface acoustic wave device that measures the frequency of the surface acoustic wave device and adjusts the frequency of the device according to the frequency shift, after measuring the frequency of each device in the wafer in the state of the wafer, Divide and divide into individual elements, classify into elements of the same frequency band, determine the etching time of elements in each frequency band, fix multiple elements in the same frequency band, and fix the electrode surface of those elements A method of manufacturing a surface acoustic wave device, wherein the oxide film is removed by etching for a predetermined time, the electrode film is further etched for a predetermined time, and the frequency of these devices is adjusted collectively.

In the method of manufacturing a surface acoustic wave device that measures the frequency of the surface acoustic wave device and adjusts the frequency of the device according to the frequency shift, after measuring the frequency of each device in the wafer in the state of the wafer, The oxide film on the electrode surface of the element is removed by etching for a predetermined time, the wafer is diced and divided into individual elements, classified into elements of the same frequency band, and the etching time of the elements in each frequency band is determined, A method of manufacturing a surface acoustic wave device, comprising fixing a plurality of devices in the same frequency band, further etching the electrode film for a predetermined time, and adjusting the frequency of the devices collectively.