JP3687601B2 - ELECTRONIC COMPONENT ELEMENT, ITS MANUFACTURING METHOD, AND ELECTRONIC COMPONENT DEVICE - Google Patents

Description

【００５９】
このように電極パッドをＩＤＴ部等の素子部と別体に設けることにより、クラック発生を抑制できて、歩留りを改善できる。また、ＮｉＣｒ（Ｔｉ）層１５を設けたことによって、クラック発生をより一層抑制できて、歩留りを改善できる。さらに、Ａｌ酸化層１４を設けたことで、クラック発生をより一層抑制できて、歩留りを改善できる。特に、対策３については、大量にサンプルを作成してその効果の再現性を確認している。
【００６０】
なお、上記では、電子部品装置や電子部品素子として、弾性表面波装置１や弾性表面波素子２の例を挙げたが、酸化物基板上にバンプボンディング用に電極パッドを有するものであれば、特に限定されるものではなく、酸化物基板として誘電体基板を用いる積層コンデンサや、積層インダクタにも本発明は適用可能である。
【００６１】
【発明の効果】
本発明の電子部品素子は、以上のように、電子回路のための素子部が素子基板上に形成され、上記素子部を外部と電気的に接続するための電極パッドが金属バンプを用いたフェースダウン実装用に設けられ、上記電極パッドは、素子部から延びるＡｌ又はＡl合金／Ｔｉ下地の二層構造の引き出し電極上に電極パッドの一部が重ね合わされており、Ａｌ又はＡl合金からなるパッド電極層と、電極パッド上に設けられる金属バンプの拡散を抑制するためのバリア層とを有し、バリア層は、パッド電極層の中間に設けられている構成である。
【００６２】
それゆえ、上記構成は、電極パッド上に設けられる金属バンプの拡散を抑制するためのバリア層をパッド電極層の中間に設けたことによって、金属バンプの金属が電極パッド内に拡散することを上記バリア層により抑制できる。
【００６３】
これにより、上記構成は、上記拡散に勤する体積膨張を伴う金属間化合物の形成領域を素子基板から離すことができて、上記金属間化合物による悪影響を軽減でき、素子基板にクラックが発生することを軽減できるという効果を奏する。
【図面の簡単な説明】
【図１】本発明の実施の形態にかかる弾性表面波素子の要部断面図である。
【図２】上記弾性表面波素子を、パッケージに収納した弾性表面波装置の概略断面図である。
【図３】上記弾性表面波素子の平面図である。
【図４】上記弾性表面波素子の製造方法を示す、フローチャートである。
【図５】上記弾性表面波素子における、下地にＴｉ層を設けたことによるＡｌ層の配向性を示すための、Ｘ線回折図である。
【図６】下地にＴｉ層を設けない場合の、Ａｌ層の配向性を示すための、Ｘ線回折図である。
【符号の説明】
１ 弾性表面波装置
２ 弾性表面波素子
３ 圧電基板（素子基板、酸化物基板）
４、５ 弾性表面波フィルタ（素子部）
４ｃ、５ｃ 引き出し電極
６ 入力電極（電極パッド）
７ 出力電極（電極パッド）
８ アース電極（電極パッド）
６ａ、７ａ、８ａ 引き回し電極
１５ ＮｉＣｒ（Ｔｉ）層（バリア層）
１６ Ａｌ酸化層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component element suitable for face-down mounting in which metal bumps formed on an element substrate of an electronic component element are pressed against and connected to an electrode pattern of a package made of ceramic or the like, a circuit board, etc. The present invention relates to an electronic component device.
[0002]
[Prior art]
In recent years, with the downsizing and low profile of electronic component devices such as mobile phones, as a method of connecting the electrode pads of the electronic component elements used in the electronic component device and the electrode pattern of the package, instead of the connection method using wires, A face-down connection method has been developed in which the functional surface of the electronic component element is directly mounted facing the connection surface of the package. In such a face-down method, Au bumps are often used for connection between the electrode pads of the electronic component element and the electrode pattern of the package because of easy connection and dimensional controllability.
[0003]
As a surface acoustic wave device (hereinafter referred to as a SAW device) which is such an electronic component element, for example, a SAW device described in Japanese Patent Application Laid-Open No. 2000-91870 is known. The SAW device includes a piezoelectric substrate (element substrate, oxide substrate), a surface acoustic wave element (hereinafter referred to as an IDT) and an external connection terminal provided on a main surface of the piezoelectric substrate. Two layers in which a second electrode metal layer made of Al or the like is laminated on a first electrode metal layer made of aluminum (Al) or an Al alloy having an element portion) and an external connection terminal constituting an IDT A first region having a structure and a second region in which the second electrode metal layer is directly disposed on the piezoelectric substrate.
[0004]
However, the conventional two-layer structure electrode is used as an electrode for an element part of an acoustic surface wave (hereinafter referred to as SAW) filter as an electronic component element or an electrode pad that requires high power resistance such as a duplexer. If this happens, there is a problem that it is not possible to cope with high power durability.
[0005]
Therefore, in order to avoid the above problem, the present inventor considered using the structure of the above publication for an electrode having an Al / Ti structure that is used for improving power durability.
[0006]
[Problems to be solved by the invention]
However, when the structure of the above publication is used for an electrode having an Al / Ti structure, it has been found that there is a problem that cracks occur in the piezoelectric substrate under the bumps. It has been found that when Ti is used for the base of the electrode and mounting is performed by the face-down method, hard Ti cannot completely relax the thermal stress at the time of sealing the package.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, an electronic component element according to the present invention has an element part for an electronic circuit formed on an element substrate, and electrode pads for electrically connecting the element part to the outside are metal bumps. A part of the electrode pad is overlapped on a lead electrode having a two-layer structure of Al or Al alloy / Ti base extending from the element portion. It has a pad electrode layer made of an alloy and a barrier layer for suppressing diffusion of metal bumps provided on the electrode pad, and the barrier layer is provided in the middle of the pad electrode layer.
[0008]
According to the above configuration, the electrode of the surface portion of the surface acoustic wave (hereinafter referred to as SAW) filter as an electronic component element, which requires high power resistance such as a duplexer, and the electrode pad are formed of Al (with Ti as a base). By forming an (alloy) film, the power durability is dramatically improved due to the effect of enhancing the orientation of the Al (alloy) film and the ability to reinforce the portion of the electrode bottom where the electrostatic stress is concentrated with a hard metal. it can.
[0009]
Further, in the above configuration, by providing a barrier layer for suppressing the diffusion of the metal bumps provided on the electrode pad in the middle of the pad electrode layer, it is possible to prevent the metal in the metal bumps from diffusing into the electrode pad. Can be suppressed by layer.
[0010]
Thereby, the said structure can separate the formation area | region of the intermetallic compound accompanying the volume expansion which acts on the said diffusion from an element substrate, can reduce the bad influence by the said intermetallic compound, and a crack generate | occur | produces in an element substrate. Can be avoided.
[0011]
The electronic component element preferably further has an Al oxide layer at the interface on the element substrate side between the pad electrode layer made of Al or Al alloy and the barrier layer.
[0012]
According to the said structure, by providing an Al oxide layer further, it can suppress by the said Al oxide layer that the metal of a barrier layer diffuses in an electrode pad.
[0013]
In the electronic component element, the barrier layer is preferably made of at least one selected from the group consisting of NiCr, Cr, Ti, Ni, Ta, and W.
[0014]
Further, in the above-described configuration having high power durability, a lift-off vapor deposition method is used on the ground and input / output electrodes that serve as Al / Ti electrode pads formed on the element substrate (piezoelectric substrate) by a dry etching method or a lift-off method. Furthermore, by providing it together with a barrier layer (intermediate electrode layer) made of NiCr alloy or Ti having good adhesive strength with Al in the middle of a pad electrode layer made of pure Al or about Al-1 wt% Cu alloy having a thickness of about 1 μm. The electrode pad thickness sufficient for bonding can be ensured.
[0015]
In the above electronic component element, the metal bump provided on the electrode pad is preferably made of Au or Pt.
[0016]
In the above electronic component element, the metal bump provided on the electrode pad may be made of solder.
[0017]
According to the above configuration, the effect of the barrier layer can be more effectively exhibited by the metal bump being made of Au, Pt, or solder, which is excellent in bondability, in particular, Au or Pt that easily forms an intermetallic compound. .
[0018]
In the electronic component element, the element unit is an interdigital transducer of Al or A l alloy / Ti underlayer having a two-layer structure, and the element substrate, between the IDT and the extraction electrode, an oxygen-containing Ti layer It is desirable to be provided.
[0019]
According to the above configuration, by having the oxygen-containing Ti layer, oxygen in the element substrate is absorbed by Ti in the thermal process of sealing, so that the crystallinity of the element substrate is found and the fracture strength is reduced. Is suppressed by the oxygen-containing Ti layer, and the generation of cracks in the element substrate under the electrode pad can be reduced.
[0020]
In the electronic component element, the element unit is an interdigital transducer of Al or A l alloy / Ti underlayer having a two-layer structure, it is IDT and the lead-out electrode which is prepared using a lift-off method preferable.
[0021]
According to the above configuration, since the electrode having a two-layer structure of Al or Al alloy / Ti is formed by the lift-off method, damage to the element substrate can be reduced, and generation of cracks in the element substrate can be suppressed.
[0022]
In order to solve the above-described problems, the method of manufacturing an electronic component element according to the present invention includes an element part and a lead layer composed of an Al or Al alloy / Ti electrode connected to the element part on an oxide substrate. After forming an electrode, a bump pad pattern is formed with a resist in a region different from the element portion, subjected to ion cleaning in a reduced pressure state, Al or Al alloy is formed by vacuum deposition, and then an oxygen atmosphere. It is characterized in that the surface is oxidized by exposing the substrate to vapor , and the barrier layer and A1 or Al alloy are deposited again in a vacuum state, and then the resist is removed together with unnecessary metal.
[0023]
In the electronic component element manufacturing method, the barrier layer is preferably formed using at least one selected from the group consisting of NiCr, Cr, Ti, Ni, Ta, and W.
[0024]
In the above-described method of manufacturing an electronic component device, the step of performing said ion cleaning, the step of depositing Al or an Al alloy, forming a barrier layer with surface oxidation by an oxygen atmosphere Al or A l alloy was the vapor deposition, A series of steps of vapor-depositing Al or Al alloy may be continuously processed with one vacuum vapor deposition apparatus.
[0025]
In order to solve the above problems, an electronic component device according to the present invention is characterized in that the electronic component element described above is housed in a package by face-down mounting.
[0026]
In the above manufacturing method, when forming an element portion such as an IDT, the lead electrodes are also formed at the same time, but it is preferable that the bump electrode pad portion is formed separately by a lift-off method thereafter. .
[0027]
The electrode structure of the electrode pad portion is formed by forming an Al alloy as the lowermost layer, oxidizing the surface once, and then successively forming a barrier layer such as NiCr (or Ti) → Al alloy. Eventually, a four-layer structure of Al alloy / barrier layer / AI oxide layer / Al alloy / element substrate (oxide substrate, piezoelectric substrate) is obtained.
[0028]
Further, a part of the lead electrode extending from the electrode pad was superposed on a part of the lead electrode extending from the previously formed element portion such as IDT, thereby establishing electrical connection between the two.
[0029]
Here, the reason why the electrode pad is not made of a single layer of Al (alloy) is that a metal bump such as Au and Al or an Al alloy generate an intermetallic compound, so intermetallic compound formation → volume expansion (compound Al ₂ Au This is because the volume is approximately twice that of Al ₂ + Au) → stress accumulation → crack generation, and cracks are likely to occur.
[0030]
Therefore, in order to keep the formation region of the intermetallic compound as far as possible from the element substrate, it is desirable to provide an intermediate electrode layer of NiCr or Ti as a barrier layer of Au. In addition, it is preferable to provide an Al oxide layer between the NiCr (Ti) intermediate electrode layer and the underlying Al layer. The reason is that the barrier layer of Ti or NiCr diffuses into the underlying Al alloy and the intermetallic compound is removed. This is to prevent the formation.
[0031]
In the case where Al (alloy) is directly formed on the Al oxide layer, adhesion cannot be ensured and Au cannot be prevented from diffusing. In order to establish conduction between the element part such as IDT and the electrode pad for bumps, the lead electrode formed simultaneously with the element part such as IDT and the part of the lead electrode formed simultaneously with the electrode pad for bump are overlapped. Since the portion is not a region where the chip-shaped electronic component element is bonded to the package, mechanical bonding strength is not required.
[0032]
Therefore, there is no problem even if Al is directly formed on the Al oxide film. In order for the barrier layer such as NiCr (Ti) to exhibit the effect as a barrier of the metal bumps such as Au, a film thickness of at least 10 nm is necessary. Since the Al natural oxide film grows only a few nm at most, the effect as a barrier layer of metal bumps such as Au cannot be expected.
[0033]
The electronic component element of the present invention, such as a SAW device using a flip-chip method, is formed on a piezoelectric substrate and is highly oriented aluminum (Al—Cu alloy) / Ti highly oriented with titanium or the like as a base film. A part of the IDT element part and the lead electrode formed from the multilayer film is formed first, and an electrode pad for forming a bump for connecting to the external electrode and a part of the lead electrode are provided on the piezoelectric substrate. It is formed in a region other than the element, and has a configuration in which both (the element part and the pad part) are routed on the extraction electrode which is the element electrode to electrically connect both of them (the element part and the pad part). .
[0034]
As a result, it is possible to provide a surface acoustic wave device having both high power durability and high reliability in which the generation of cracks in the piezoelectric substrate is reduced under the electrode bumps. In the above configuration, when the Ti layer is formed on the piezoelectric substrate, it is desirable that an oxygen-containing Ti layer is formed at the interface between the Ti layer and the piezoelectric substrate.
[0035]
The electrode pad for external connection is preferably formed by a lift-off method. For the IDT element portion, a lift-off method or a dry etching method can be used, but the lift-off method is more preferable because it is damage-free.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
A surface acoustic wave device as an electronic component device according to the present invention will be described below with reference to FIGS. As shown in FIG. 2, the surface acoustic wave device 1 is obtained by mounting a surface acoustic wave element 2 as an electronic component element face-down in a package 9 made of ceramic.
[0037]
The surface acoustic wave element 2 is electrically and mechanically connected to electrode patterns 9 a and 9 b made of Au formed on the inner bottom surface of the package 9 by Au bumps 10. The external electrodes 9c and 9d are made of Au and are connected to the electrode patterns 9a and 9b, respectively.
[0038]
As shown in FIG. 3, the surface acoustic wave element 2 includes a piezoelectric substrate (element substrate, oxide substrate) 3 such as lithium tantalate (LT), and each surface acoustic wave filter (element portion) 4 on the piezoelectric substrate 3. 5, IDTs 4 a and 5 a and reflectors 4 b and 5 b, and input electrodes 6, output electrodes 7, and ground electrodes 8 connected to the extraction electrodes 4 c and 5 c of the IDTs 4 a and 5 a, respectively.
[0039]
The IDTs 4a and 5a and the reflectors 4b and 5b are provided along the propagation direction of the surface acoustic wave. The extraction electrodes 4c and 5c of the IDTs 4a and 5a are provided so as to extend in a direction orthogonal to the propagation direction of the surface acoustic wave. The conduction between the IDTs 4a and 5a and the input electrode 6, the output electrode 7 and the ground electrode 8 is such that the ends of the lead electrodes 4c and 5c of the IDT 4a and 5a The electrodes 6a, 7a, and 8a are secured by overlapping and contacting each other.
[0040]
Each IDT 4a, 5a, each reflector 4b, 5b, and each extraction electrode 4c, 5c are laminated on the Ti layer 11 with a Ti layer 11 having a thickness of 5 nm to 100 nm as a base layer as shown in FIG. The thin film having a thickness of about 100 nm to 400 nm is formed of the Al layer 12 having a thickness of 100 nm to 300 nm. The Al layer 12 may be, for example, an Al alloy to which 1 wt% of copper is added.
[0041]
Although not shown, an oxygen-containing Ti layer is formed between the Ti layer 11 and the piezoelectric substrate 3. The oxygen-containing Ti layer is not particularly limited as long as it contains oxygen. For example, the oxygen-containing Ti layer may be one in which oxygen is incorporated into a Ti crystal or may be a Ti oxide.
[0042]
Among these electrodes, the IDTs 4a and 5a of the surface acoustic wave filters 4 and 5, the reflectors 4b and 5b, and the lead electrodes 4c and 5c are element electrodes (element portions) for the surface acoustic wave element 2 to function. The input electrode 6, the output electrode 7, and the ground electrode 8 are electrode pads for electrical and physical connection with the circuit board and the package 9.
[0043]
The input electrode 6, the output electrode 7, and the ground electrode 8 have pad electrode layers 13 and 16 made of Al or Al alloy having a thickness of about 1.5 μm and formed on the piezoelectric substrate 3.
[0044]
In each of the pad electrode layers 13 and 16 of the input electrode 6, the output electrode 7, and the ground electrode 8, a NiCr (or Ti) layer 15 serving as a barrier layer is laminated between the pad electrode layers 13 and 16. It has been. Therefore, the pad electrode layers 13 and 16 are made of Al or Al alloy having a film thickness of about 500 nm and made of Al or Al alloy, and having a film thickness larger than that of the lower electrode layer 13 and having a film thickness of about 1 μm. And the upper electrode layer 16.
[0045]
Further, an Al oxide layer 14 is provided between the pad electrode layers 13 and 16 and the NiCr (or Ti) layer 15 on the interface on the piezoelectric substrate 3 side, that is, between the lower electrode layer 13 and the NiCr (or Ti) layer 15. It is preferable that
[0046]
Next, a method for manufacturing the surface acoustic wave element 2 according to the present invention will be described with reference to the flowcharts of FIGS. First, a resist pattern is formed on the piezoelectric substrate 3 such as LT or lithium niobate (LN), and the Ti layer 11 (about 10 nm) and the Al (alloy) layer 12 (about 200 nm) are maintained without breaking the vacuum. Then, the respective films are sequentially formed by continuous vapor deposition (Step 1, hereinafter, Step is referred to as S). When the Ti layer 11 is formed, at the interface between the Ti layer 11 and the piezoelectric substrate 3, the Ti layer 11 deprives the oxygen contained in the piezoelectric substrate 3 to form an oxygen-containing Ti layer.
[0047]
By doing so, no oxide film is formed at the interface between the Ti layer 11 and the Al layer 12, so that the Al layer 12 has a uniaxial [111] crystal axis aligned in a direction perpendicular to the surface direction of the piezoelectric substrate 3. An alignment film is formed (see FIG. 5). The aligned Al layer 12 is resistant to SAW stress and stress migration is less likely to occur. When the Ti layer 11 was not provided, the orientation of the Al layer 12 was deteriorated as shown in FIG.
[0048]
Thereafter, an IDT composed of an Al (alloy) layer 12 / Ti layer 11, a reflector, and an extraction electrode are formed by a lift-off method in which the resist is peeled off with an organic solvent. This portion may be formed by a process of resist pattern formation → dry etching → resist peeling after an Al (alloy) / Ti electrode is formed on the entire surface of the wafer. However, in this case, the influence of the damage on the space portion cannot be completely eliminated as compared with the lift-off method. For this reason, the lift-off method is preferable in the present invention.
[0049]
Next, a part of the lead-out electrode and the bump pad electrode are formed again by the lift-off method. Specifically, the following procedure is followed. First, after an IDT, a reflector, and an extraction electrode are formed, a resist pattern in which the extraction electrode and the bump pad pattern are opened is formed on the piezoelectric substrate 3 (S2).
[0050]
After that, Al (alloy) (film thickness of about 500 nm) was formed on the piezoelectric substrate 3 by vacuum deposition (S3), oxygen was once introduced into the vacuum apparatus, and an Al oxide layer which is a natural oxide film on the Al surface. 14 is formed with a film thickness of 1 nm to 7 nm (S4). This may be formed by introducing air. It has been confirmed that the Al oxide layer 14 having such a thickness can exhibit a barrier function, but hardly affects the conductivity.
[0051]
Next, the inside of the vacuum apparatus is again evacuated to a vacuum of about 10 ⁻² (1E-2) Pa, Ar gas is once introduced, and ion cleaning is performed with Ar ion bombardment (S5), and then the vacuum apparatus The inside is evacuated to about 10 ⁻⁵ (1E-5) Pa, and a NiCr (or Ti) layer 15 (20 nm) and Al (alloy) (1 μm) are continuously formed (S6, S7), and finally The resist is eluted with an organic solvent, and unnecessary portions of the metal are removed by peeling (S8) to complete the electrode structure.
[0052]
By superimposing a part of the routing electrode on top of the previously formed extraction electrode, conduction between the IDT and the electrode pad can be ensured.
[0053]
Thus, the Au bump 10 is formed on the formed upper electrode layer 16 by the ball bonding method. Specifically, the above-mentioned ball is pressure-bonded onto the upper electrode layer 16 while applying ultrasonic waves to the ball formed at the tip of the Au wire, and then the Au wire is cut from the ball portion to form the Au bump 10. It is formed on the upper electrode layer 16.
[0054]
The surface acoustic wave element 2 formed through the above-described steps is opposed to the electrode patterns 9a and 9b formed on the package 9 with the surface (IDT throat forming surface) interposed therebetween via the Au bump 10. It is pressed while applying sound waves and heat to connect to the package 9. Next, the surface acoustic wave device 1 is completed by hermetically sealing the package 9 with the lid 9e using solder. At this time, heat of about 300 ° C. is applied to the surface acoustic wave element 2 during hermetic sealing with solder.
[0055]
In the above embodiment, the piezoelectric substrate (element substrate) 3 has been described using a piezoelectric substrate made of lithium tantalate or lithium niobate. However, the present invention is not limited to this. For example, a zinc oxide film is provided. The same effect can be obtained with a piezoelectric substrate such as an insulating substrate, crystal, or langasite.
[0056]
By using the following measures, the effects of the present invention relating to the influence of heating on the surface acoustic wave element 2 during hermetic sealing with solder were confirmed as shown in Table 1, respectively.
[0057]
Monitor (comparative example): When the lower layer electrode under the bump is Al / Ti and NiCr → Al (alloy) is continuously formed thereon.
Countermeasure 1: In the case where the electrode under the bump is separately formed by a process different from that of Al / Ti in the IDT portion to form an Al (alloy) single layer.
Countermeasure 2: When the electrode pad for the bump of Measure 1 is a three-layer film of Al (alloy) / NiCr (Ti) / Al (alloy) / substrate.
Countermeasure 3: When the lowermost layer of Al (alloy) is formed by vacuum deposition, the surface is once oxidized, and NiCr → Al (alloy) is continuously formed thereon.
[0058]
[Table 1]

[0059]
Thus, by providing the electrode pad separately from the element portion such as the IDT portion, the occurrence of cracks can be suppressed and the yield can be improved. In addition, by providing the NiCr (Ti) layer 15, the generation of cracks can be further suppressed, and the yield can be improved. Furthermore, by providing the Al oxide layer 14, the generation of cracks can be further suppressed and the yield can be improved. In particular, for measure 3, a large number of samples are prepared and the reproducibility of the effect is confirmed.
[0060]
In the above, examples of the surface acoustic wave device 1 and the surface acoustic wave element 2 are given as the electronic component device and the electronic component element. However, if the electrode pad is provided on the oxide substrate for bump bonding, The present invention is not particularly limited, and the present invention can also be applied to a multilayer capacitor using a dielectric substrate as an oxide substrate and a multilayer inductor.
[0061]
【The invention's effect】
In the electronic component element of the present invention, as described above, the element part for the electronic circuit is formed on the element substrate, and the electrode pad for electrically connecting the element part to the outside uses a metal bump. Provided for down-mounting, the electrode pad is a pad made of Al or Al alloy, in which a part of the electrode pad is superimposed on a two-layer lead electrode of Al or Al alloy / Ti base extending from the element portion It has an electrode layer and a barrier layer for suppressing diffusion of metal bumps provided on the electrode pad, and the barrier layer is provided in the middle of the pad electrode layer.
[0062]
Therefore, the configuration described above is that the metal of the metal bumps diffuses into the electrode pad by providing a barrier layer for suppressing the diffusion of the metal bumps provided on the electrode pad in the middle of the pad electrode layer. It can be suppressed by the barrier layer.
[0063]
Thereby, the said structure can separate the formation area | region of the intermetallic compound accompanying the volume expansion which works on the said diffusion from an element substrate, can reduce the bad influence by the said intermetallic compound, and a crack generate | occur | produces in an element substrate. The effect that can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a principal part of a surface acoustic wave element according to an embodiment of the present invention.
FIG. 2 is a schematic sectional view of a surface acoustic wave device in which the surface acoustic wave element is housed in a package.
FIG. 3 is a plan view of the surface acoustic wave element.
FIG. 4 is a flowchart showing a method for manufacturing the surface acoustic wave element.
FIG. 5 is an X-ray diffraction diagram for illustrating the orientation of an Al layer by providing a Ti layer as a base in the surface acoustic wave device.
FIG. 6 is an X-ray diffraction diagram for illustrating the orientation of an Al layer when a Ti layer is not provided as a base.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Surface acoustic wave apparatus 2 Surface acoustic wave element 3 Piezoelectric substrate (element substrate, oxide substrate)
4, 5 Surface acoustic wave filter (element part)
4c, 5c Lead electrode 6 Input electrode (electrode pad)
7 Output electrodes (electrode pads)
8 Ground electrode (electrode pad)
6a, 7a, 8a Lead electrode 15 NiCr (Ti) layer (barrier layer)
16 Al oxide layer

Claims (11)

An element part for an electronic circuit is formed on an element substrate,
An electrode pad for electrically connecting the element part to the outside is provided for face-down mounting using a metal bump,
In the electrode pad, a part of the electrode pad is superimposed on a two-layered lead electrode of Al or Al alloy / Ti base extending from the element portion, and a pad electrode layer made of Al or Al alloy and the electrode pad And a barrier layer for suppressing diffusion of metal bumps provided in the
An electronic component element, wherein the barrier layer is provided in the middle of the pad electrode layer.   2. The electronic component element according to claim 1, further comprising an Al oxide layer at an interface on the element substrate side between the pad electrode layer made of Al or an Al alloy and the barrier layer.   3. The electronic component element according to claim 1, wherein the barrier layer is made of at least one selected from the group consisting of NiCr, Cr, Ti, Ni, Ta, and W.   4. The electronic component element according to claim 1, wherein the metal bump provided on the electrode pad is made of Au or Pt. 5.   4. The electronic component element according to claim 1, wherein the metal bumps provided on the electrode pads are made of solder. 5. The element portion is a comb-type electrode portion having a two-layer structure of Al or Al alloy / Ti base,
The electronic component element according to claim 1, wherein an oxygen-containing Ti layer is provided between the element substrate, the comb-shaped electrode portion, and the extraction electrode. The element portion is a comb-type electrode portion having a two-layer structure of Al or Al alloy / Ti base,
The electronic component element according to claim 1, wherein the comb-shaped electrode portion and the extraction electrode are formed by using a lift-off method. On the oxide substrate, an element part and a lead electrode composed of a two-layer electrode of Al or Al alloy / Ti connected to the element part are formed, and then a bump pad pattern is formed in a region different from the element part. After forming with a resist and performing ion cleaning in a reduced pressure state, an Al or Al alloy film is formed by vacuum deposition, and then exposed to an oxygen atmosphere to oxidize the surface and again in a vacuum state with the barrier layer and Al or Al. A method of manufacturing an electronic component element, comprising depositing an alloy and then removing the resist together with an unnecessary metal.   9. The method of manufacturing an electronic component element according to claim 8, wherein the barrier layer is manufactured using at least one selected from the group consisting of NiCr, Cr, Ti, Ni, Ta, and W.   A series of steps of performing the ion cleaning, depositing Al or Al alloy, forming a barrier layer by surface oxidizing the deposited Al or Al alloy in an oxygen atmosphere, and depositing Al or Al alloy. 10. The method of manufacturing an electronic component element according to claim 8, wherein the steps are continuously processed by a single vacuum deposition apparatus.   8. An electronic component device, wherein the electronic component element according to claim 1 is housed in a package by face-down mounting.

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