PatentDe  


Dokumentenidentifikation EP1033810 28.06.2007
EP-Veröffentlichungsnummer 0001033810
Titel Herstellungsverfahren für akustische Oberflächenwellenanordnungen
Anmelder Murata Manufacturing Co., Ltd., Nagaokakyo, Kyoto, JP
Erfinder Taga, Shigeto, Nagaokakyo-shi, Kyoto-fu 617-8555, JP
Vertreter Schoppe, Zimmermann, Stöckeler & Zinkler, 82049 Pullach
DE-Aktenzeichen 60034836
Vertragsstaaten DE, FI, FR, GB, SE
Sprache des Dokument EN
EP-Anmeldetag 02.03.2000
EP-Aktenzeichen 004005625
EP-Offenlegungsdatum 06.09.2000
EP date of grant 16.05.2007
Veröffentlichungstag im Patentblatt 28.06.2007
IPC-Hauptklasse H03H 9/05(2006.01)A, F, I, 20051017, B, H, EP
IPC-Nebenklasse H03H 3/08(2006.01)A, L, I, 20051017, B, H, EP   

Beschreibung[en]
BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a method of manufacturing a surface acoustic wave apparatus in which a surface acoustic wave element is sealed in a package.

2. Description of the Related Art

Conventionally, a surface acoustic wave apparatus is formed by connecting and fixing a surface acoustic wave element onto a base member through bump bonding, then by sealing the surface acoustic wave element in a package defined by bonding a cap member onto the base member. In the past, with such a surface acoustic wave apparatus, a seam welding method has been used and a Kovar alloy is used to define a joint so as to form an air-tight fixation between the base member and the cap member.

Further, sealing methods other than the seam welding method include a wax sealing method which requires that a wax material is applied to connecting portions of either the base member or the cap member, a small heater block is then contacted with for example the cap member, thereby heating the cap member so as to melt the wax material, followed by a cooling treatment to join the base member with the cap member.

When the above seam welding method is used to join the base member to the cap member, during a seam welding process, the connecting portion of either the cap member or the base member is only partially heated so as to be elevated to a high temperature, resulting in the base member and the cap member being joined together under a condition involving a significant temperature difference between the connecting portions and other portions. Then, with the cooling of the surface acoustic wave apparatus, a large residual stress is generated between the base member and the cap member, hence causing the base member 10 and the cap member 30 to deform significantly, as shown in Fig. 3. Subsequently, because of such a deformation, stress is concentrated on metal bumps 51 which have been used to connect and fix the surface acoustic wave element 20 on to the base member 10, and is also concentrated on electrodes 12 and 25 combined with metal bumps 51. Accordingly, there had been a problem that the metal bumps 51 and the electrodes 12, 25 would be damaged and are caused to peel off, resulting in some defective connections and defective characteristics.

When the wax sealing method is used to join the base member with the cap member, there also arises a problem that the base member would be deformed after the above joining treatment due to the same reason mentioned above, causing problems similar to problems occurring in the seam welding method.

Note that it is necessary to provide a space for allowing for free vibration of the electrodes on the surface (surface acoustic wave propagating surface) of the surface acoustic wave element. However, since it is impossible to fill a space between the surface acoustic wave element and the base member with a resin using a process similar to forming a semiconductor device, it is impossible to reduce or eliminate the stress concentrated on the metal bumps, hence making it impossible to improve the joint strength. Accordingly, in order to improve the reliability of a surface acoustic wave apparatus, it is extremely important to reduce the stress exerted on the metal bumps.

EP-A-0 608 827 discloses a technique for applying uniform heating to cap and base members of a package in order to bond those members together However, the bonding material is melted glass and the piezoelectric plate is bonded to the base member using an adhesive.

The paper "Miniaturized SAW filters using a flip-chip technique" by Yatsuda et al (IEEE Proc. Ultrasonics Symposium, vol.1,1 Nov 1994) describes a SAW filter in which the SAW chip is bonded to a base member using gold bonding bumps. The package cap is bonded using Au-Sn alloy solder.

SUMMARY OF THE INVENTION

In order to overcome the problems described above, preferred embodiments of the present invention provide a method of manufacturing a surface acoustic wave apparatus which reduces and minimizes a stress exerted on the metal bumps during a process of joining the base member and the cap member, and prevents problems occurring in connecting portions of the metal bumps, thereby ensuring a sufficient reliability.

The present invention provides a method of manufacturing a surface acoustic wave apparatus comprising the step of: bump-bonding a surface acoustic wave element and a base member together through bumps having a melting point of 450°C or higher such that the surface acoustic wave element is fixed with a face down configuration to a bottom surface of a recess of the base member; characterized by further comprising the step of bonding a cap member and the base member with a bonding material selected from the group consisting of a solder, an Au-Sn alloy, or a low melting point glass, by heating the cap member and the base member uniformly at a temperature higher than the melting point of the bonding material to melt the bonding material, said temperature being lower than 450°C.

With the use of the above manufacturing method, since there is no temperature difference between the different members during the process of joining together the base member and the cap member, a residual stress exerted on the surface acoustic wave apparatus after cooling treatment is minimized, thus greatly reducing the stress on the metal bump connecting portions. For this reason, it is possible to reliably and greatly reduce damage to the metal bumps and damage to the electrodes connected on the bump connecting portions, and to greatly reduce connection problems such as the peeling-off of the metal bumps or bump connecting portions. However, the surface acoustic wave element may be bump bonded or joined in advance by way of metal bumps having a melting point of 450°C or higher, so as to be strongly supported and fixed on the base member while at the same time being electrically connected.

As mentioned above, the wax material is a solder, an Au-Sn alloy, or a low melting point glass which has a softening point of not more than 450°C.

As described in the above, according to preferred embodiments of the present invention, the surface acoustic wave element is strongly connected and fixed on the base member via metal bumps having a melting point of 450°C or higher and the surface acoustic wave apparatus as a whole is uniformly heated so as to join the base member with the cap member, thereby greatly reducing a stress exerted on the metal bump connecting portions. Therefore, it is possible to prevent the connection problems occurring in the metal bumps and the bump connecting portions, thereby obtaining a surface acoustic wave apparatus having a high reliability.

For the purpose of illustrating the invention, there is shown in the drawings several forms which are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

BRIEF DESCRIPTION OF THE DRAWINGS

  • Fig. 1 is a cross sectional view of a surface acoustic wave apparatus made according to a preferred embodiment of the present invention.
  • Fig. 2 is a plan view indicating a surface acoustic wave element made according to a preferred embodiment.
  • Fig. 3 is a brief cross sectional view for explaining a deformation occurring during a process when the base member and the cap member are joined together to form a conventional surface acoustic wave apparatus.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention are explained in detail with reference to the drawings.

Fig. I is a cross sectional view illustrating a surface acoustic wave apparatus manufactured according to a preferred embodiment of the present invention, and Fig. 2 is a plan view illustrating a surface acoustic wave element shown in Fig. 1.

In the surface acoustic wave apparatus, a plurality of electrode pads 25 of the surface acoustic wave element 20 and a plurality of electrode lands 12 formed on the surface of a recess portion of a base member 10 are bump bonded through metal bumps 51 with a face-down configuration. The surface acoustic wave element 20 is fixed and supported on the base member 10 and is electrically connected thereon. Further, a cap member 30 is joined with the base member 10 via a wax material 52 having a high melting point such that the surface acoustic wave element 20 is covered up. Thus, the surface acoustic wave element 20 may be air-tightly sealed in the package (within the space) defined by the base member 10 and the cap member 30. In this surface acoustic wave apparatus, between the surface acoustic wave propagating surface of the surface acoustic wave element 20 and the base member 10, a gap (a space) is provided for more efficiently propagating the surface acoustic wave, as shown in Fig. 1.

The surface acoustic wave element 20 includes, as shown in Fig. 2, a piezoelectric substrate 21. On the upper surface of the piezoelectric substrate 21, there is an electrode pattern including IDT (interdigital transducer) electrodes 22, reflector electrodes 23, outlet electrodes 24 extending from all of the IDT electrodes 22, and electrode pads 25 connected with all of the outlet electrodes 24. The electrode pattern is preferably made of A1 or it may be made of an alloy containing A1, and is preferably formed by using a known film formation method. As the piezoelectric substrate 21, it is possible to use a piezoelectric material such as lithium tantalate or lithium niobate or other suitable material.

The base member 10 preferably has a concave configuration and is formed preferably by laminating a plurality of ceramic layers, and has an input/output electrode pattern and an earth electrode pattern including a plurality of electrode lands 12 extending on its underside surface, the inner surface of its recess portion and inside itself. Although not shown in the drawings, input and output terminal electrodes are provided on the underside surface of the base member 10. Using the underside surface of the base member 10 as a mounting surface, the surface acoustic wave apparatus may be mounted on a mounting board (a circuit board).

The cap member 30 is preferably a metal plate made of a Fe-Ni alloy or an alloy containing Fe, or other suitable material, and may be subjected to a plating treatment if necessary.

The surface acoustic wave apparatus is preferably manufactured in the following way. At first, a ball-bonding method is preferably used to form a metal bump 51 on each electrode pad 25 of the surface acoustic wave element 20, with each metal bump 51 preferably made of Au or a material containing Au as its main component. Then, the surface acoustic wave element 20 is arranged face down such that its surface acoustic wave propagating surface including IDTs and other electrodes is caused to face toward the base member 10, followed by the simultaneous application of a supersonic wave and heat. In this way, each electrode pad 25 and its corresponding electrode land 12 of the base member 10 are joined together through a metal bump 51, thereby connecting and fixing the surface acoustic wave element 20 on the base member 10.

It is not necessary to form each metal bump 51 of Au, and it is possible to form the metal bump 51 of other metal materials, provided that such metal materials do not easily become molten or softened during a subsequent process for joining together the base member 10 and the cap member 30 and that such materials have a melting point of 450°C or higher.

Although the above description has explained a method in which a supersonic wave and heat may be simultaneously applied during the above bump joining process, it is also possible to use a method in which only a supersonic wave or heat is applied during the above bump joining process. Further, a method of forming the metal bumps is not necessarily limited to the ball-bonding method. It is also possible to use other methods for forming the metal bumps, such as a bump formation method involving a plating treatment.

Next, the cap member 30 on which a wax for forming the wax material 52 and having a high melting point is mounted so as to press on the cap member, is laid over the base member 10. Then, the cap member 30 and the base member 10 are introduced into a reflow furnace so that the base member 10, the surface acoustic wave element 20 and the cap member 30 are all uniformly heated, to a temperature higher than the melting point of the wax material 52, as indicated by arrows in Fig. 1, thereby melting the wax material 52 and thus causing the base member 10 and the cap member 30 to be joined together. At the time, the temperature for heat is not more than 450°C so that the bump does not melt.

In this way, with the use of the method for manufacturing the surface acoustic wave apparatus according to the present preferred embodiment, since the base member and the cap member are joined together in a process where the surface acoustic wave apparatus as a whole is uniformly heated, there will be no temperature difference between the different members during the joining treatment. Therefore, a residual stress exerted on the surface acoustic wave apparatus after cooling treatment is minimized to be extremely small, thus greatly reducing the stress on the metal bump connecting portions. For this reason, it is possible to reliably and greatly reduce damage of the metal bumps and damage of the electrodes connected on the bump connecting portions, and to greatly reduce connection problems such as the peeling-off of these members, thereby making it possible to improve the yield, reduce the rate of failure, and achieve great improvements in its reliability.

The wax material is selected from the group consisting of a solder, an Au-Sn alloy or a low melting point glass. Further, although it has been described in the above preferred embodiment that the wax material was mounted on the cap member pressing the same, it is also possible that the wax material may be formed in advance on the base member, or alternatively it may be formed through printing treatment.

Further, although it has been described in the above preferred embodiment that a reflow furnace may be used to join together the base member and the cap member, the present invention is not so limited. It is also possible to use a heating furnace or an oven capable of uniformly heating the entire surface acoustic wave apparatus.

Moreover, a material forming the cap member should not be limited to the Fe-Ni alloy or an alloy containing Fe. It is also possible to use other material capable of achieving an excellent airtight sealing property when used with the wax material. Further, a material for forming the cap member should not be limited to a metal. It is also possible to use a ceramic material to form the cap member. In such a case, it is possible to use a low melting point glass as a wax material. In addition, it is possible to use a base member formed of a metal.

Further, the shapes of the base member and the cap member should not be limited to that in the above described preferred embodiment. It is also possible, for example, to make a package defined by a flat plate like base member and a concave cap member. Moreover, the electrode pattern of the surface acoustic wave element should not be limited to that of the above preferred embodiment.

While preferred embodiments of the invention have been disclosed, various modes of carrying out the principles disclosed herein are contemplated as being within the scope of the following claims. Therefore, it is understood that the scope of the invention is not to be limited except as otherwise set forth in the claims.


Anspruch[de]
Ein Verfahren zum Herstellen einer Oberflächenwellenvorrichtung, das folgenden Schritt aufweist: Bump-Verbinden eines Oberflächenwellenelements (20) und eines Basisbauglieds (10) miteinander durch Bumps (51), die einen Schmelzpunkt von 450°C oder höher aufweisen, derart, dass das Oberflächenwellenelement (20) mit einer Oberseite-nach-unten-Konfiguration an einer unteren Oberfläche einer Ausnehmung des Basisbauglieds (10) fixiert ist; dadurch gekennzeichnet, dass dasselbe ferner den Schritt eines Verbindens eines Abdeckungsbauglieds (30) und des Basisbauglieds (10) mit einem Verbindungsmaterial (52), das aus der Gruppe ausgewählt ist, die aus einem Lötmittel, einer Au-Sn-Legierung und einem Glas mit niedrigem Schmelzpunkt besteht, durch ein Erwärmen des Abdeckungsbauglieds (30) und des Basisbauglieds (10) einheitlich auf eine Temperatur, die höher als der Schmelzpunkt des Verbindungsmaterials liegt, um das Verbindungsmaterial zu schmelzen, wobei die Temperatur geringer als 450°C ist, aufweist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß Anspruch 1, bei dem eine Mehrzahl von Elektrodenanschlussflächen (25) an dem Oberflächenwellenelement (20) vorgesehen sind und eine Mehrzahl von Elektrodenanschlussbereichen (12) an der Oberfläche der Ausnehmung des Basisbauglieds (10) vorgesehen sind und die Bumps (51) die Elektrodenanschlussflächen (25) und die Elektrodenanschlussbereiche (12) verbinden. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß Anspruch 1 oder 2, bei dem die Bumps (51), die während des Bump-Verbindungsprozesses verwendet werden, aus einem Metall hergestellt sind. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß einem der vorhergehenden Ansprüche, bei dem das Oberflächenwellenelement (20) auf eine luftdichte Weise in dem Gehäuse abgedichtet ist, das durch das Basisbauglied (10) und das Abdeckungsbauglied (30) definiert ist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß einem der vorhergehenden Ansprüche, bei dem ein Zwischenraum zwischen dem Oberflächenwellenelement (20) und dem Basisbauglied (10) definiert ist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß einem der vorhergehenden Ansprüche, bei dem das Oberflächenwellenelement (20) ein piezoelektrisches Substrat (21) und Interdigitalwandlerelektroden (22), Reflektorelektroden (23), Auslasselektroden (24), die sich von den Interdigitalwandlerelektroden erstrecken, und Elektrodenanschlussflächen (25), die mit den Auslasselektroden verbunden sind, umfasst. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß Anspruch 6, bei dem das piezoelektrische Substrat (21) aus Lithiumtantalat oder Lithiumniobat hergestellt ist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß Anspruch 6 oder 7, bei dem die Elektrodenstruktur entweder aus Al oder einer Legierung ist, die Al enthält. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß einem der vorhergehenden Ansprüche, bei dem das Basisbauglied (10) eine konkave Konfiguration aufweist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß einem der vorhergehenden Ansprüche, bei dem das Basisbauglied (10) durch ein Laminieren einer Mehrzahl von Keramikschichten gebildet ist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß einem der vorhergehenden Ansprüche, bei dem das Abdeckungsbauglied (30) eine Metallplatte umfasst, die aus einer Fe-Ni-Legierung oder einer Legierung, die Fe enthält, hergestellt ist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß einem der vorhergehenden Ansprüche, das ferner den Schritt eines simultanen Anlegens einer Überschallwelle und von Wärme umfasst, so dass das Oberflächenwellenelement (20) mit einer Oberseite-nach-unten-Konfiguration an der unteren Oberfläche der Ausnehmung des Basisbauglieds (10) fixiert ist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß Anspruch 12, bei dem eine Mehrzahl von Elektrodenanschlussflächen (25) an dem Oberflächenwellenelement (20) vorgesehen ist und eine Mehrzahl von Elektrodenanschlussbereichen (12) an der Oberfläche der Ausnehmung des Basisbauglieds (10) vorgesehen ist und jede Elektrodenanschlussfläche (25) nach der Anlegung der Überschallwelle und der Wärme über den Bump (54) mit einem der Elektrodenanschlussbereiche (12) verbunden ist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß einem der Ansprüche 1 bis 11, das ferner den Schritt eines Anlegens einer Überschallwelle oder von Wärme umfasst, so dass das Oberflächenwellenelement (20) mit einer Oberseite-nach-unten-Konfiguration an der unteren Oberfläche der Ausnehmung des Basisbauglieds (10) fixiert ist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß Anspruch 14, bei dem eine Mehrzahl von Elektrodenanschlussflächen (25) an dem Oberflächenwellenelement (20) vorgesehen ist und eine Mehrzahl von Elektrodenanschlussbereichen (12) an der Oberfläche der Ausnehmung des Basisbauglieds (10) vorgesehen ist und jede Elektrodenanschlussfläche (25) nach der Anlegung einer Überschallwelle oder von Wärme über den Bump (51) mit einem der Elektrodenanschlussbereiche (12) verbunden ist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß einem der vorhergehenden Ansprüche, bei dem die Bumps (51) aus einem Material hergestellt sind, das Au umfasst. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß einem der vorhergehenden Ansprüche, bei dem der Bump-Verbindungsprozess ein Kugelverbindungsprozess ist. Das Verfahren zum Herstellen einer Oberflächenwellenvorrichtung gemäß einem der Ansprüche 1 bis 11, das ferner den Schritt eines Platzierens des Abdeckungsbauglieds (30) und des Basisbauglieds (10) in einen Aufschmelzofen aufweist, um das Basisbauglied (10), das Oberflächenwellenelement (20) und das Abdeckungsbauglied (30) einheitlich auf die Temperatur zu erwärmen, die höher als der Schmelzpunkt des Verbindungsmaterials liegt.
Anspruch[en]
A method of manufacturing a surface acoustic wave apparatus, comprising the step of: bump-bonding a surface acoustic wave element (20) and a base member (10) together through bumps (51) having a melting point of 450°C or higher such that the surface acoustic wave element (20) is fixed with a face down configuration to a bottom surface of a recess of the base member (10); characterized by further comprising the step of bonding a cap member (30) and the base member (10) with a bonding material (52) selected from the group consisting of a solder, an Au-Sn alloy and a low melting point glass, by heating the cap member (30) and the base member (10) uniformly at a temperature higher than the melting point of the bonding material to melt the bonding material, said temperature being lower than 450°C. The method of manufacturing a surface acoustic wave apparatus according to claim 1, wherein a plurality of electrode pads (25) are provided on the surface acoustic wave element (20) and a plurality of electrode lands (12) are provided on the surface of the recess of the base member (10), and the bumps (51) connect the electrode pads (25) and the electrode lands (12). The method of manufacturing a surface acoustic wave apparatus according to claim 1 or 2, wherein the bumps (51) used during the bump bonding process are made of metal. The method of manufacturing a surface acoustic wave apparatus according to any previous claim, wherein the surface acoustic wave element (20) is sealed in an air-tight manner in the package defined by the base member (10) and the cap member (30). The method of manufacturing a surface acoustic wave apparatus according to any previous claim, wherein a gap is defined between the surface acoustic wave element (20) and the base member (10). The method of manufacturing a surface acoustic wave apparatus according to any previous claim, wherein the surface acoustic wave element (20) includes a piezoelectric substrate (21) and interdigital transducer electrodes (22), reflector electrodes (23), outlet electrodes (24) extending from the interdigital transducer electrodes, and electrode pads (25) connected with the outlet electrodes. The method of manufacturing a surface acoustic wave apparatus according to claim 6, wherein the piezoelectric substrate (21) is made of one of lithium tantalate and lithium niobate. The method of manufacturing a surface acoustic wave apparatus according to claim 6 or 7, wherein the electrode pattern is of one of Al and an alloy containing Al. The method of manufacturing a surface acoustic wave apparatus according to any previous claim, wherein the base member (10) has a concave configuration. The method of manufacturing a surface acoustic wave apparatus according to any previous claim, wherein the base member (10) is formed by laminating a plurality of ceramic layers. The method of manufacturing a surface acoustic wave apparatus according to any previous claim, wherein the cap member (30) includes a metal plate made of one of a Fe-Ni alloy and an alloy containing Fe. The method of manufacturing a surface acoustic wave apparatus according to any previous claim, further including the step of simultaneously applying a supersonic wave and heat so that the surface acoustic wave element (20) is fixed with a face down configuration to the bottom surface of the recess of the base member (10). The method of manufacturing a surface acoustic wave apparatus according to claim 12, wherein a plurality of electrode pads (25) are provided on the surface acoustic wave element (20) and a plurality of electrode lands (12) are provided on the surface of the recess of the base member (10), and each electrode pad (25) is joined to one of the electrode lands (12) via the bump (54) after the application of the supersonic wave and heat. The method of manufacturing a surface acoustic wave apparatus according to any one of Claims 1 to 11, further including the step of applying one of a supersonic wave and heat so that the surface acoustic wave element (20) is fixed with a face down configuration to the bottom surface of the recess of the base member (10). The method of manufacturing a surface acoustic wave apparatus according to claim 14, wherein a plurality of electrode pads (25) are provided on the surface acoustic wave element (20) and a plurality of electrode lands (12) are provided on the surface of the recess of the base member (10), and each electrode pad (25) is joined to one of the electrode lands (12) via the bump (51) after the application of the one of a supersonic wave and heat. The method of manufacturing a surface acoustic wave apparatus according to any previous Claim, wherein the bumps (51) are made of a material including Au. The method of manufacturing a surface acoustic wave apparatus according to any previous Claim, wherein the bump-bonding process is a ball-bonding process. The method of manufacturing a surface acoustic wave apparatus according to any one of Claims 1 to 11, further comprising the step of placing the cap member (30) and the base member (10) into a reflow furnace to uniformly heat the base member (10), the surface acoustic wave element (20) and the cap member (30) to said temperature higher than the melting point of the bonding material.
Anspruch[fr]
Procédé de fabrication d'un dispositif à ondes acoustiques de surface comprenant l'étape consistant à : lier par bossages un élément à ondes acoustiques de surface (20) et un élément de base (10) l'un à l'autre par l'intermédiaire de bossages (51) ayant un point de fusion de 450°C ou supérieur de sorte que l'élément à ondes acoustiques de surface (20) soit fixé avec une configuration face vers le bas à une surface inférieure d'un évidement de l'élément de base (10) ; caractérisé en ce qu'il comprend en outre l'étape de liaison d'un élément de recouvrement (30) et de l'élément de base (10) par un matériau de liaison (52) sélectionné dans le groupe consistant en une soudure, un alliage de Au-Sn, ou un verre à point de fusion bas, en chauffant l'élément de recouvrement (30) et l'élément de base (10) uniformément à une température supérieure au point de fusion du matériau de liaison pour faire fondre le matériau de liaison, ladite température étant inférieure à 450°C. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon la revendication 1, dans lequel une pluralité de pastilles d'électrode (25) sont prévues sur l'élément à ondes acoustiques de surface (20) et une pluralité de plages d'électrode (12) sont prévues sur la surface de l'évidement de l'élément de base (10), et les bossages (51) relient les pastilles d'électrode (25) et les plages d'électrode (12). Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon la revendication 1 ou 2, dans lequel les bossages (51) utilisés au cours du processus de liaison par bossages sont réalisés en un métal. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon l'une quelconque des revendications précédentes, dans lequel l'élément à ondes acoustiques de surface (20) est enfermé d'une manière étanche à l'air dans le boîtier défini par l'élément de base (10) et l'élément de recouvrement (30). Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon l'une quelconque des revendications précédentes, dans lequel un espace est défini entre l'élément à ondes acoustiques de surface (20) et l'élément de base (10). Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon l'une quelconque des revendications précédentes, dans lequel l'élément à ondes acoustiques de surface (20) comprend un substrat piézoélectrique (21) et des électrodes de transducteur interdigital (22), des électrodes de réflexion (23), des électrodes de sortie (24) s'étendant à partir des électrodes de transducteur interdigital, et des pastilles d'électrode (25) connectées aux électrodes de sortie. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon la revendication 6, dans lequel le substrat piézoélectrique (21) est réalisé en l'un du tantalate de lithium et du niobate de lithium. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon la revendication 6 ou 7, dans lequel le motif d'électrodes est l'un de l'Al et d'un alliage contenant de l'Al. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon l'une quelconque des revendications précédentes, dans lequel l'élément de base (10) présente une configuration concave. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon l'une quelconque des revendications précédentes, dans lequel l'élément de base (10) est formé en lamifiant une pluralité de couches de céramique. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon l'une quelconque des revendications précédentes, dans lequel l'élément de recouvrement (30) comprend une plaque métallique réalisée en l'un d'un alliage de Fe-Ni et d'un alliage contenant du Fe. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon l'une quelconque des revendications précédentes, comprenant en outre l'étape consistant à appliquer simultanément une onde ultrasonore et de la chaleur de sorte que l'élément à ondes acoustiques de surface (20) soit fixé selon une configuration face vers le bas à la surface inférieure de l'évidement de l'élément de base (10). Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon la revendication 12, dans lequel une pluralité de pastilles d'électrode (25) sont prévues sur l'élément à ondes acoustiques de surface (20) et une pluralité de plages d'électrode (12) sont prévues sur la surface de l'évidement de l'élément de base (10), et chaque pastille d'électrode (25) est jointe à l'une des plages d'électrode (12) par l'intermédiaire du bossage (54) après l'application de l'onde ultrasonore et de la chaleur. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon l'une quelconque des revendications 1 à 11, comprenant en outre l'étape consistant à appliquer l'une d'une onde ultrasonore et de chaleur de sorte que l'élément à ondes acoustiques de surface (20) soit fixé selon une configuration face vers le bas à la surface inférieure de l'évidement de l'élément de base (10). Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon la revendication 14, dans lequel une pluralité de pastilles d'électrode (25) sont prévues sur l'élément à ondes acoustiques de surface (20) et une pluralité de plages d'électrode (12) sont prévues sur la surface de l'évidement de l'élément de base (10), et chaque pastille d'électrode (25) est jointe à l'une des plages d'électrode (12) par l'intermédiaire du bossage (54) après l'application de l'une d'une onde ultrasonore et de chaleur. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon l'une quelconque des revendications précédentes, dans lequel les bossages (51) sont réalisés en un matériau comprenant de l'Au. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon l'une quelconque des revendications précédentes, dans lequel le processus de liaison par bossages est un processus de soudage par écrasement de boule. Procédé de fabrication d'un dispositif à ondes acoustiques de surface selon l'une quelconque des revendications 1 à 11, comprenant en outre l'étape consistant à placer l'élément de recouvrement (30) et l'élément de base (10) dans un four de refusion pour chauffer uniformément l'élément de base (10), l'élément à ondes acoustiques de surface (20) et l'élément de recouvrement (30) à ladite température supérieure au point de fusion du matériau de liaison.






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