JPS6223486B2 - - Google Patents
Info
- Publication number
- JPS6223486B2 JPS6223486B2 JP54157447A JP15744779A JPS6223486B2 JP S6223486 B2 JPS6223486 B2 JP S6223486B2 JP 54157447 A JP54157447 A JP 54157447A JP 15744779 A JP15744779 A JP 15744779A JP S6223486 B2 JPS6223486 B2 JP S6223486B2
- Authority
- JP
- Japan
- Prior art keywords
- aluminum
- electrode
- input
- substrate
- electrodes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 229910052782 aluminium Inorganic materials 0.000 claims description 18
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 18
- 239000000758 substrate Substances 0.000 claims description 13
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 3
- 239000012299 nitrogen atmosphere Substances 0.000 claims description 3
- 238000000206 photolithography Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 2
- 238000002425 crystallisation Methods 0.000 claims 1
- 230000008025 crystallization Effects 0.000 claims 1
- 230000007423 decrease Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- 229910013641 LiNbO 3 Inorganic materials 0.000 description 1
- 239000011358 absorbing material Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/08—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of resonators or networks using surface acoustic waves
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Description
【発明の詳細な説明】
この発明は表面波フイルタの製造方法の改良の
改良に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method of manufacturing surface wave filters.
表面波フイルタは第１図に示すようにステム１
上に表面波フイルタ用圧電素子２が接着され、こ
の素子表面に形成された電極とステムリード３と
をボンデイングワイヤ４で接続したのちシエル５
を冠着して形成されている。前記圧電素子を製造
するには、LiTaO3やLiNbO3などの圧電体ウエハ
の一主面を鏡面にし、その上に金属たとえばアル
ミニウムを蒸着してのち所定の形状の入力電極お
よび出力電極のパターン群を形成する。次にそれ
ら入力電極と出力電極との外側にそれぞれ吸音剤
を塗布する。その後このように形成されたウエハ
をダイシングして所定の圧電素子が得られるもの
である。その１例を第２図に示す。圧電基板１１
上に形成された１２は入力電極、１３は出力電極
にして、１４は吸音層である。 The surface wave filter has stem 1 as shown in Figure 1.
A piezoelectric element 2 for a surface wave filter is bonded on top, and the electrode formed on the surface of this element and the stem lead 3 are connected with a bonding wire 4, and then the shell 5 is bonded.
It is formed by wearing a crown. To manufacture the piezoelectric element, one main surface of a piezoelectric wafer such as LiTaO 3 or LiNbO 3 is mirror-finished, a metal such as aluminum is vapor-deposited thereon, and then a pattern group of input electrodes and output electrodes of a predetermined shape is formed. form. Next, a sound absorbing material is applied to the outside of each of the input electrode and output electrode. Thereafter, the wafer thus formed is diced to obtain predetermined piezoelectric elements. An example is shown in FIG. Piezoelectric substrate 11
12 formed on the top is an input electrode, 13 is an output electrode, and 14 is a sound absorption layer.
アルミニウムがウエハ表面に蒸着されてからほ
どこされる種々の工程、たとえばエツチング工程
やダイシング工程等の工程で圧電基板とアルミニ
ウム膜との密着性が低下して次のような欠点が生
ずる。すなわち基板上の電極とリードとをワイヤ
ボンデイングするときに電極を形成しているアル
ミニウム膜が基板からはがれることが起こつた
り、ボンデイング不良が発生することがある。ま
た電極を形成しているアルミニウム膜と基板との
密着性にばらつきがあつたり、密着性の低下が起
こつて、入力電極から出力電極に向つて伝播する
表面波の音速にばらつきが生じ、表面波フイルタ
の周波数特性不良の原因となつていた。 The adhesion between the piezoelectric substrate and the aluminum film decreases during various steps such as etching and dicing that are performed after aluminum is deposited on the wafer surface, resulting in the following drawbacks. That is, when wire-bonding electrodes and leads on a substrate, the aluminum film forming the electrodes may peel off from the substrate, or bonding defects may occur. In addition, the adhesion between the aluminum film forming the electrode and the substrate may vary or decrease, resulting in variations in the sound speed of surface waves propagating from the input electrode to the output electrode. This was the cause of poor frequency characteristics of the filter.
この発明はこのような欠点を除去するためにな
されたものであつて、圧電基板上に形成されたア
ルミニウム蒸着膜からなる入出力電極の基板への
密着性を向上させた表面波フイルタの製造方法の
提供を目的とするものである。すなわち圧電体ウ
エハの一主面にアルミニウムを蒸着して、写真食
刻法で所定形状の入力電極と出力電極とのパター
ン群を形成してのち窒素雰囲気中でアルミニウム
の再結晶温度近くの温度で熱処理をほどこして、
電極と基板との密着性を向上させたことを特徴と
するものである。 The present invention was made to eliminate these drawbacks, and provides a method for manufacturing a surface wave filter that improves the adhesion of input/output electrodes made of an aluminum vapor-deposited film formed on a piezoelectric substrate to the substrate. The purpose is to provide the following. That is, aluminum is vapor-deposited on one main surface of a piezoelectric wafer, a pattern group of input electrodes and output electrodes of a predetermined shape is formed by photolithography, and then aluminum is deposited at a temperature close to the recrystallization temperature of aluminum in a nitrogen atmosphere. After heat treatment,
It is characterized by improved adhesion between the electrode and the substrate.
以下この発明の実施例について説明する。
LiTaO3からなる62mmφのウエハの一主面を鏡面
とし、この鏡面に真空蒸着によりアルミニウムを
蒸着して0.8〜1.5μ程度の蒸着膜を形成する。次
に写真食刻法によつて所定形状の櫛歯状の入力電
極と出力電極とのパターン群を形成する。このよ
うにされたウエハを窒素雰囲気中で300゜〜400℃
で30分〜60分間熱処理する。この温度はアルミニ
ウムの再結晶温度近くの温度である。このような
処理がほどこされて、アルミニウム蒸着膜からな
る入力電極と出力電極の表面には0.7〜1.5μφ程
度の多数の成長核が形成される。第３図にその概
要を示す。１２′は入力電極にして１３′は出力電
極である。以下所定の工程を経て表面波フイルタ
が得られる。 Examples of the present invention will be described below.
One principal surface of a 62 mmφ wafer made of LiTaO 3 is made into a mirror surface, and aluminum is deposited on this mirror surface by vacuum evaporation to form a deposited film of about 0.8 to 1.5 μm. Next, a pattern group of comb-shaped input electrodes and output electrodes having a predetermined shape is formed by photolithography. The wafer made in this way is heated at 300° to 400°C in a nitrogen atmosphere.
Heat-treat for 30 to 60 minutes. This temperature is close to the recrystallization temperature of aluminum. As a result of this treatment, a large number of growth nuclei of about 0.7 to 1.5 μφ are formed on the surfaces of the input and output electrodes made of the aluminum vapor deposited film. Figure 3 shows the outline. 12' is an input electrode, and 13' is an output electrode. A surface wave filter is obtained through the following predetermined steps.
このような熱処理が行われたために、アルミニ
ウム蒸着膜と圧電基板との密着性が向上し、ばら
つきもほとんどなくなつた。その結果ワイヤボン
デイングするときにアルミニウム膜がはがれてボ
ンデイング不良となることも防止でき、アルミニ
ウム膜の密着性が向上し、かつ均一に密着されて
いるために、基板表面における表面波の音速にば
らつきがなくなり、周波数特性の不良の減少がは
かられるという効果を奏するものである。 Since such heat treatment was performed, the adhesion between the aluminum vapor deposited film and the piezoelectric substrate was improved, and variations were almost eliminated. As a result, it is possible to prevent the aluminum film from peeling off during wire bonding, resulting in defective bonding.The adhesion of the aluminum film is improved, and the uniform adhesion reduces variations in the sound velocity of surface waves on the substrate surface. This has the effect of reducing frequency characteristic defects.
第１図は表面波フイルタの側面図、第２図は表
面波フイルタの平面図、第３図はこの発明の１実
施例の平面図である。
１…ステム、２…圧電素子、３…ステムリー
ド、４…ボンデイングワイヤ、１１…圧電基板、
１２…入力電極、１３…出力電極、１４…吸音
層、１２′…入力電極、１３′…出力電極。
FIG. 1 is a side view of a surface wave filter, FIG. 2 is a plan view of the surface wave filter, and FIG. 3 is a plan view of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Stem, 2... Piezoelectric element, 3... Stem lead, 4... Bonding wire, 11... Piezoelectric substrate,
12... Input electrode, 13... Output electrode, 14... Sound absorbing layer, 12'... Input electrode, 13'... Output electrode.
Claims (1)
の工程と、写真食刻法によりこのアルミニウム層
から入力電極と出力電極とをこの圧電基板上に形
成する第２の工程と、窒素雰囲気中にて前記入力
電極と前記出力電極とをアルミニウムの再結晶温
度近くの温度で熱処理する第３の工程とを具備す
ることを特徴とする表面波フイルタの製造方法。1 The first step of forming an aluminum layer on the piezoelectric substrate
a second step of forming an input electrode and an output electrode from this aluminum layer on this piezoelectric substrate by photolithography; and a second step of forming an input electrode and an output electrode from aluminum in a nitrogen atmosphere. A method for manufacturing a surface wave filter, comprising a third step of heat treatment at a temperature close to the crystallization temperature.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15744779A JPS5680912A (en) | 1979-12-06 | 1979-12-06 | Piezoelectric element for surface wave filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15744779A JPS5680912A (en) | 1979-12-06 | 1979-12-06 | Piezoelectric element for surface wave filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5680912A JPS5680912A (en) | 1981-07-02 |
| JPS6223486B2 true JPS6223486B2 (en) | 1987-05-23 |
Family
ID=15649850
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15744779A Granted JPS5680912A (en) | 1979-12-06 | 1979-12-06 | Piezoelectric element for surface wave filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5680912A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52138442A (en) * | 1976-05-17 | 1977-11-18 | Hitachi Ltd | Method of forming metal membrane |
-
1979
- 1979-12-06 JP JP15744779A patent/JPS5680912A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52138442A (en) * | 1976-05-17 | 1977-11-18 | Hitachi Ltd | Method of forming metal membrane |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5680912A (en) | 1981-07-02 |
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