JP2007335468A - Hollow sealed element, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow sealed element that is superior in airtight sealing property, as well as its manufacturing method. <P>SOLUTION: A function section 20 having a mechanical movable part, an internal electrode 30 connected to the function section 20, and a sealing section 40 enclosing the function section 20 and the internal electrode 30, are formed on an insulative substrate 10. A cover substrate 50 is placed on the function section 20, the internal electrode 30, and the sealing section 40, thus forming an air gap 70 between the function section 20 and the cover substrate 50. In this case, bonding interfaces are made by anode bonding 80 between the internal electrode 30 and the cover substrate 50, and between the sealing section 40 and the cover substrate 50. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a functional unit such as a surface acoustic wave (SAW) element, a bulk acoustic wave (BAW) element, or a micro electro-mechanical system (MEMS) constituting a micro switch used in a mobile communication device such as a mobile phone. The present invention relates to a downsizing package technology for an element that requires hollow sealing.

  As a typical example of the hollow sealed package, description will be made by taking as an example the package technology of a SAW element mounted on a mobile phone or the like.

  Since the SAW element needs to vibrate the comb-teeth electrode portion formed on the piezoelectric substrate with low loss, it is impossible to package the device surface by directly molding the device surface with a sealing resin or the like.

  Therefore, conventionally, a SAW element chip is die-bonded face-up to a ceramic casing, electrically connected by wire bonding, and then covered with a metal cap and packaged by seam welding or solder sealing. Recently, in order to reduce the size of the device, the SAW element chip is flip-chip bonded (face-down bonding) to the wiring substrate by Au bumps or solder bumps, and sealed with resin or the like while forming a gap on the comb-tooth electrode portion. Small package devices are in practical use.

  More recently, in order to reduce the size and height of the device, the entire piezoelectric wafer on which the comb electrodes are formed is sealed with a glass plate while forming gaps on the comb electrodes, and external electrodes are formed, followed by dicing. Ultra-small package devices that have been separated into individual devices have been proposed.

  For example, the SAW element described in the following Patent Document 1 is the above-described ultra-small package device. FIG. 14 shows an overall cross-sectional structure of the device, and FIG. .

  As shown in FIG. 14, on the element substrate 10 made of a piezoelectric material, a functional unit 20 composed of comb-shaped electrodes and an internal electrode 30 electrically connected thereto are formed. A sealing portion 40 containing Al as a main component is formed on the periphery of the element substrate 10, and a cover base 50 that protects the functional portion 20 while forming the gap portion 70 on the functional portion 20 is sealed from the internal electrode 30. It is placed over the stop 40. A through hole 60 is formed in advance on the cover base 50 at a position facing the internal electrode 30, and the external electrode 90 and the printed electrode 95 are formed so as to fill the through hole 60. Thus, the internal electrode 30 and the printing electrode 95 are electrically connected.

The device is sealed by placing a cover base 50 on the element substrate 10, connecting an anode electrode to the sealing portion 40 at 350 ° C., connecting a cathode electrode to the cover base 50, and applying 500 V. Thus, sealing was completed by anodic bonding. Reference numeral 80 in FIG. 15 denotes an anodic bonding portion formed at the interface between the sealing portion 40 and the portion of the cover base 50 in contact therewith.
Japanese Patent Laid-Open No. 1996-213874 JP 2003-110391 A

The conventional hollow package structure shown in FIGS. 14 and 15 has the following problems.
First, as shown in FIG. 14, only the bonding interface between the sealing portion 40 and the cover base 50 is anodic bonded, and the bonding interface between the internal electrode 30 and the cover base 50 is not bonded, resulting in an unbonded portion 85. Yes.

  The junction between the internal electrode 30 and the external electrode 90 is formed by a Ti, Cu laminated film by a sputtering process. However, the thickness of this portion is as thin as about 2 μm, and the bonding is limited to a small portion of the ring-shaped sealing portion 35. Since the sputtering process is usually performed at a high temperature, the ring-shaped sealing portion 35 made of the Ti and Cu laminated film is cracked due to the generation of internal stress due to the difference in thermal expansion between the element substrate 10 and the cover base 50 in the process of returning to room temperature after sputtering. May occur and airtightness may be impaired.

  In addition, the through hole 60 is formed in a hollow shape, and voids are generated when the printing electrode 95 is formed there by paste printing mainly composed of Cu, which may impair airtightness.

  Regarding the securing of the airtight sealability of the through hole 60, the following solution is proposed in Patent Document 2. In this method, one opening of a through hole formed in a cover base is sealed in advance with a metal plate serving as an external electrode by anodic bonding, and a metal braze is introduced into the through hole. The cover base is placed on the element substrate on which the comb electrode, the internal electrode and the sealing portion are formed, and the sealing portion and the cover base are anodically bonded, and the metal brazing in the through hole is melted, The internal electrode and the external electrode are electrically connected through a metal solder. However, in this method, it is necessary to perform anodic bonding twice, which complicates the process and lowers the work efficiency.

  The next problem is that the element substrate 10 on which the functional part 20 such as the comb-teeth electrode, the internal electrode 30 and the sealing part 40 are formed and the cover base 50 on which the through hole 60 and the like are precisely aligned with the wafer size. In this state, anodic bonding must be performed, and therefore an expensive manufacturing apparatus is required.

  Further, as shown in FIG. 16, a large number of elements are formed in alignment on a wide element substrate 10, and an integration anode is used to apply a voltage for anodic bonding to the sealing portion 40 of each element at a time. It is necessary to form the junction terminal 45. At this time, in order to electrically connect the sealing portion 40 between the elements, for example, it is necessary to provide a connection portion made of a conductive material mainly composed of Al, which is the same as the sealing portion 40. Since this connecting portion always overlaps with the dicing line 140, different materials having different hardnesses between the element substrate 10 and the connecting portion made of the conductive material must be diced at the same time. There are problems such as short life.

  An object of the present invention is to provide a hollow sealing element having a high hermetic sealing property and a manufacturing method thereof.

In order to achieve the above object, the first means of the present invention includes a functional part having a mechanically movable part, an internal electrode electrically connected to the functional part, and a sealing part surrounding the functional part and the internal electrode. Are formed on an insulating substrate such as an element substrate described later,
A cover base is placed on the functional part, the internal electrode, and the sealing part to form a gap between the functional part and the cover base, and the bonding interface between the sealing part and the cover base is sealed. In the hollow sealing element to be
The bonding interface between the internal electrode and the cover substrate and the bonding interface between the sealing portion and the cover substrate are both anodic bonded.

  According to a second means of the present invention, in the first means, the internal electrode is formed thicker than the functional part, the sealing part has substantially the same thickness as the internal electrode, and the cover base is the same It is comprised by the board | plate material which has thickness.

  According to a third means of the present invention, in the first or second means, the cover base is made of glass.

  According to a fourth means of the present invention, in the first to third means, the internal electrode and the sealing portion are made of a material containing aluminum as a main component.

According to a fifth means of the present invention, in the first to fourth means, the electrical resistivity of the insulating substrate is restricted to a range of 1 × 10 ⁻⁷ Ω · cm to 1 × 10 ⁻¹³ Ω · cm. It is characterized by being.

  According to a sixth means of the present invention, in the first means, a through hole for electrode connection is formed at a position facing the central portion of the internal electrode of the cover base, and the internal electrode in the peripheral portion of the through hole The bonding interface is anodically bonded.

  According to a seventh means of the present invention, in the sixth means, an external electrode is formed in the through hole by electroplating or electroless plating as will be described later.

  According to an eighth means of the present invention, in any of the first to seventh means, the functional part is composed of a pair of comb electrodes facing each other, and the hollow sealing element is a surface acoustic wave element. To do.

According to a ninth means of the present invention, a functional part having a mechanically movable part, an internal electrode electrically connected to the functional part, and a sealing part surrounding the functional part and the internal electrode are made into one set. Forming a large number of sets on the insulating substrate with a predetermined gap;
A step of placing a cover base on the insulating base so as to be in contact with each set of internal electrode and sealing part, and forming a gap between each functional part and the cover base;
An anode electrode is in contact with the lower surface of the insulating substrate, a cathode electrode is in contact with the upper surface of the cover substrate, a voltage is applied between the anode electrode and the cathode electrode, and each internal electrode and the cover substrate are A step of anodic bonding the bonding interface and the bonding interface between each sealing portion and the cover base;
Removing the anode electrode and the cathode electrode, and dicing the cover base and the insulating base along the dicing lines in the gaps of the respective sets to separate them into individual hollow sealing elements. Is.

  According to a tenth means of the present invention, in the ninth means, the internal electrode is formed thicker than the functional part, the sealing part has substantially the same thickness as the internal electrode, and the cover base is the same. It is comprised by the board | plate material which has thickness.

  The eleventh means of the present invention is the ninth or tenth means characterized in that the cover base is made of glass.

  A twelfth means of the present invention is characterized in that, in the ninth to eleventh means, the internal electrode and the sealing portion are made of a material mainly composed of aluminum.

According to a thirteenth means of the present invention, in the ninth to twelfth means, the electrical resistivity of the insulating substrate is restricted to a range of 1 × 10 ⁻⁷ Ω · cm to 1 × 10 ⁻¹³ Ω · cm. It is characterized by being.

The fourteenth means of the present invention includes the step of forming a through hole for electrode connection at a position facing the central portion of the internal electrode of the cover base after the anodic bonding step in the ninth means,
The anodic bonding portion remains at the bonding interface with the internal electrode in the peripheral portion of the through hole.

  The fifteenth means of the present invention is characterized in that in the fourteenth means, after the through hole forming step, a step of forming an external electrode in the through hole is provided.

  The sixteenth means of the present invention is characterized in that, in the ninth to fifteenth means, the functional part is composed of a pair of comb electrodes facing each other, and the hollow sealing element is a surface acoustic wave element. To do.

  As described above, the present invention provides a hollow sealing element having a high hermetic sealing property and a method for manufacturing the same by anodic bonding the bonding interface between the internal electrode and the cover substrate and the bonding interface between the sealing portion and the cover substrate. can do.

  Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a process diagram for explaining a method of manufacturing a SAW element that is a representative example of a hollow sealing element according to an embodiment of the present invention.

(1) First, an element substrate 10 having a low electrical resistivity is prepared. A wafer of lithium tantalate (LiTaO ₃ ) is used as the element substrate 10. In this embodiment, a wafer having an electrical resistivity of 1 × 10 ⁻⁷ Ω · cm to 1 × 10 ⁻¹³ Ω · cm, preferably 1 × A wafer of 10 ⁻⁸ Ω · cm to 1 × 10 ⁻¹⁰ Ω · cm is used. This electrical resistivity is 7 to 1 digit lower than that of LiTaO ₃ which has been conventionally used, which is 1 × 10 ⁻¹⁴ Ω · cm.

  In this way, a piezoelectric material wafer having a low electrical resistivity is placed in a vapor made of a metal such as zinc, and the wafer is placed at a temperature lower than the Curie temperature of the wafer (for example, several degrees below the Curie temperature). It is obtained by heating at a low temperature for a predetermined time. In order to adjust the electrical resistivity to the above-described range, for example, various conditions such as the amount of the metal, the heating temperature, the heating time, the heating time, and the gas atmosphere with respect to the piezoelectric material wafer may be controlled.

From the various experimental results of the present inventors, when the electrical resistivity of the element substrate 10 is further lowered ^below 1 × 10 ⁻⁷ Ω · cm, the leakage current passing through the element substrate 10 increases, and desired electrical characteristics can be obtained. On the other hand, when the electrical resistivity is higher than 1 × 10 ⁻¹³ Ω · cm, it has been found that a sufficient anodic bonding effect cannot be obtained as in the case of the conventional element substrate. The electrical resistivity was regulated in the range of 1 × 10 ⁻⁷ Ω · cm to 1 × 10 ⁻¹³ Ω · cm.

(2) Next, the functional unit 20, the internal electrode 30 electrically connected to the functional unit 20, and the sealing unit 40 that surrounds the functional unit 20 are formed on the element substrate 10 (first layer). . In the case of a SAW element, the functional unit 20 is a pair of comb electrodes facing each other, and the internal electrode 30 is a pad electrode connected to the comb electrodes. In the SAW element, the functional unit 20, the internal electrode 30, and the sealing unit 40 are formed by sputtering or vapor deposition of a material mainly composed of Al and simultaneously patterning by a normal photolithography method. Although the film thickness is adjusted by the characteristics of the SAW element, it is usually 150 nm to 500 nm.

  As shown in FIG. 3, the element substrate 10 has a predetermined size, and the functional unit 20, the internal electrode 30, and the sealing unit 40 described above are aligned with a predetermined gap therebetween. A large number are formed in the state of being formed.

(3) Next, a material mainly composed of Al is sputtered or vapor-deposited on the internal electrode 30 and the sealing portion 40 to make it thicker by about 1 μm to 5 μm than the functional portion 20 (second layer). The patterning is preferably performed by a lift-off method so that the material remains only in a desired portion, but other photolithography methods may be used. FIG. 2 is a perspective view of the element in which the functional part 20, the internal electrode 30, and the sealing part 40 are formed in this manner.

(4) Next, by placing the sealing glass cover base 50 on the element substrate 10, the cover base 50 comes into contact with the internal electrode 30 of each element and the upper surface of the sealing portion 40. In this embodiment, soda glass is used as the cover base 50, and its thickness is preferably 50 μm to 300 μm, and has a width approximately equal to that of the element substrate 10 shown in FIG. Since the cover base 50 is a simple plate material having substantially the same thickness, precise alignment on the element substrate 10 is not necessary, and handling is easy.

  Since the internal electrode 30 and the sealing portion 40 are formed thicker than the functional portion 20 as described above, by placing the cover base 50 on the internal electrode 30 and the sealing portion 40, A gap 70 of about 1 μm to 5 μm is formed between the cover bases 50.

(5) Next, the plate-like heater / anode electrode 110 is brought into contact with the lower surface of the element substrate 10, and the plate-like cathode electrode 120 is brought into contact with the upper surface of the cover base 50. Both electrodes 110 and 120 are equal to or slightly wider than the width of the substrates 10 and 50. Both electrodes 110 and 120 are connected to the voltage application device 100, and a DC voltage of about 200V to 1200V is applied, and the heater and anode electrode 110 is maintained at a relatively low temperature of 150 ° C to 300 ° C to perform anodic bonding. .

As described above, the element substrate 10 having a relatively low electric resistivity of 1 × 10 ⁻⁷ Ω · cm to 1 × 10 ⁻¹³ Ω · cm is used, and a DC voltage is applied to the entire surface of the element substrate 10 and the cover base 50. Therefore, anodic bonding is simultaneously performed at both the bonding interface between the internal electrode 30 and the cover base 50 and the bonding interface between the sealing portion 40 and the cover base 50.

  As described above, with the element substrate 10 side as the anode and the glass cover base 50 side as the cathode, a voltage is applied between the two, thereby drifting cations such as sodium ions in the cover base 50 to the cathode side. A hermetic seal with a high sealing degree is achieved by the electrostatic attraction generated by the reaction and the reaction at the interface. When the bonding temperature is lower than 150 ° C., it is difficult for cation drift to proceed. On the other hand, when the bonding temperature is higher than 300 ° C., either or both of the stresses are caused by the difference in thermal expansion between the element substrate 10 and the cover base 50. Since it may break, it is better to regulate the joining temperature in the range of 150 ° C to 300 ° C.

  The internal electrode 30 and the sealing portion 40 are made of a material mainly composed of Al. The Al has a soft and active property for promoting the bonding reaction, and the bonding interface is formed by the metallizing effect of Al. Excellent airtightness.

(6) Next, the heater / anode electrode 110 and the cathode electrode 120 are removed, and a portion corresponding to the center portion of the internal electrode 30 and the element dividing dicing line 140 (see FIG. 3) is used by using a normal photolithography method. Except for the above, the entire upper surface of the cover base 50 is covered with a resist for sandblasting, and sandblast 130 is blown from above to be ground to form a through hole 60 at a location corresponding to the central portion of the internal electrode 30 of the cover base 50 and dicing. Grind along line 140 (see FIG. 3) to separate the elements individually.

  In sandblasting, hard brittle materials such as glass can be ground well, and relatively soft metal materials such as Al are difficult to polish. Therefore, in the drilling of the through holes 60, only the cover base 50 is ground, The internal electrode 30 on the side is hardly shaved and remains in its shape. After sandblasting, the resist for sandblasting is removed. FIG. 4 is a perspective view of the hollow sealing element (SAW element) thus manufactured.

  FIG. 5 is a cross-sectional view of the hollow sealing element (SAW element) manufactured as described above, and FIG. 6 is an enlarged cross-sectional view of the dotted line portion of FIG. As shown in FIG. 6, anodic bonding portions 80 are formed at the bonding interface between the internal electrode 30 and the cover base 50 (the peripheral portion of the through hole 60) and the bonding interface between the sealing portion 40 and the cover base 50, respectively. A hollow sealing element 1000 that maintains a high hermetic sealing state is obtained.

  Since the hollow sealing element 1000 is completely hermetically sealed as described above, the hollow sealing element 1000 is placed on the internal electrode lead frame 2100 like a normal resin mold IC as shown in FIG. Then, after the Au wire 2300 is bonded and connected to the internal electrode 30 exposed from the through hole 60, the hollow sealing mold component 2000 can be obtained by transfer molding with the mold resin 2200.

  Further, as shown in FIG. 8, the hollow sealing element 1000 can be directly face-down mounted on the circuit board 4000 through the Au bump 2400 by ultrasonic bonding. In the figure, 2500 is solder, 3000 is another chip component mounted on the circuit board 4000, and 4100 is a circuit board electrode formed on the circuit board 4000.

  9 is a cross-sectional view of a hollow sealing element according to still another embodiment, and FIG. 10 is an enlarged cross-sectional view of a dotted line portion of FIG. As shown in these drawings, a hollow sealing element 1100 with an external electrode is configured by providing an external electrode 90 that can be soldered to the through hole 60 of the cover base 50. By using the hollow sealing element 1100 with the external electrode 90 that can be soldered in this way, the mountability can be improved.

  FIG. 11 is a cross-sectional view showing an application example of the hollow sealing element 1100 with external electrodes. As shown in the figure, a hollow sealing element 1100 with external electrodes is mounted on a circuit board 4000 together with other chip components 3000 via solder 2500. By using this hollow sealing element 1100 with an external electrode, the mountability can be improved and the assembly cost can be reduced.

  12 and 13 are partially enlarged cross-sectional views showing examples of the configuration of the external electrodes. The example shown in FIG. 12 is an example in which the external electrode 90 is formed by an electroplating method, and a power supply film 91 is formed by sputtering a hollow sealing element 1000 in a wafer state by stacking 50 nm of Ti and 500 nm of Cu on the entire surface. Form. Next, a plating resist is coated on a region other than the region corresponding to the external electrode 90 portion by a normal photolithography method.

  Next, an electroplating electrode 92 is formed by electroplating to a thickness that fills the through-hole 60 with a metal material containing Ni as a main component and further containing Sn as a main component, and Au is used to ensure solder connectivity thereon. The external electrode 90 is obtained by electroplating. Thereafter, the plating resist is removed, the power feeding film other than the region where the external electrode 90 is formed is selectively removed, and finally, each hollow sealing element 1100 with external electrodes is obtained by dicing.

  The example shown in FIG. 13 is an example in which the external electrode 90 is formed by an electroless plating method, and an internal component mainly composed of Al exposed from the bottom of the through hole 60 with respect to the hollow sealing element 1000 in a wafer state. The electrode 30 is subjected to a zincate process, and a Zn substitution film 93 is formed. Next, this is immersed in an electroless Ni plating solution, Ni is deposited to a desired thickness to form an electroless plating electrode 94, and Au is electrolessly plated thereon to ensure solder connectivity. The electrode 90 is used. Finally, individual hollow sealing elements 1100 with external electrodes are obtained by dicing.

In the above-described embodiment, lithium tantalate (LiTaO ₃ ) is used as the insulating substrate. However, the present invention is not limited to this, and other materials such as lithium niobate (LiNbO ₃ ) are used. Is also possible.

  In the embodiment, the sealing portion is formed to be slightly thicker than the functional portion and the cover base is placed on the sealing portion, thereby forming a gap between the functional portion and the cover base. As shown in FIG. 4, a gap portion may be formed between the functional unit and the cover base by placing a cover base having a recess (relief part) on the part facing the functional part on the sealing part. Is possible.

  Although the SAW element has been described in the above embodiment, the present invention is not limited to this, and can be applied to all hollow sealing elements in which a mechanically movable part is present in the functional part.

It is process drawing for demonstrating the manufacturing method of the hollow sealing element which concerns on embodiment of this invention. It is a perspective view of 1 element in the middle of the manufacture process of the hollow sealing element. It is a perspective view which shows the dicing line of the hollow sealing element. It is a perspective view of the hollow sealing element which manufacture completed. It is sectional drawing of the hollow sealing element. It is an expanded sectional view of the part enclosed with the dotted line of FIG. It is sectional drawing of the hollow sealing mold components comprised using the hollow sealing element. It is sectional drawing which shows the state which mounted the hollow sealing element on the circuit board. It is sectional drawing which shows the other example of the hollow sealing element which concerns on embodiment of this invention. It is an expanded sectional view of the part enclosed with the dotted line of FIG. It is sectional drawing which shows the state which mounted the hollow sealing element with the external electrode on the circuit board. It is a partially expanded sectional view which shows the structural example of the external electrode of the hollow sealing element with the external electrode. It is a partially expanded sectional view which shows the structural example of the other external electrode of the hollow sealing element with the external electrode. It is sectional drawing of the hollow sealing element proposed conventionally. It is an expanded sectional view of the part enclosed with the dotted line of FIG. It is a perspective view which shows the dicing line of the hollow sealing element.

Explanation of symbols

  10: element substrate, 20: functional part, 30: internal electrode, 40: sealing part, 50: cover base, 60: through-hole, 70: gap part, 80: anodic bonding part, 90: external electrode, 91: sputtering Feed film, 92: electroplating electrode, 93: Zn substitution film, 94: electroless plating electrode, 95: printing electrode, 100: voltage application device, 110: heater / anode electrode, 120: cathode electrode, 130: sandblast, 140 : Dicing line, 1000: Hollow sealing element, 1100: Hollow sealing element with external electrode, 2000: Hollow sealing mold component, 2100: Lead frame, 2200: Mold resin, 2300: Au wire, 2400: Au bump, 2500 : Solder, 3000: Chip component, 4000: Circuit board, 4100: Circuit board electrode.

Claims (16)

A functional part having a mechanically movable part, an internal electrode electrically connected to the functional part, and a sealing part surrounding the functional part and the internal electrode are formed on an insulating substrate,
A cover base is placed on the functional part, the internal electrode, and the sealing part to form a gap between the functional part and the cover base, and the bonding interface between the sealing part and the cover base is sealed. In the hollow sealing element to be
A hollow sealing element characterized by anodically bonding the bonding interface between the internal electrode and the cover substrate and the bonding interface between the sealing portion and the cover substrate. The hollow sealing element according to claim 1, wherein the internal electrode is formed thicker than the functional part, the sealing part has substantially the same thickness as the internal electrode, and the cover base has the same thickness. A hollow sealing element comprising a plate material. 3. The hollow sealing element according to claim 1 or 2, wherein the cover base is made of glass. 4. The hollow sealing element according to claim 1, wherein the internal electrode and the sealing portion are made of a material mainly composed of aluminum. 5. The hollow sealing element according to claim 1, wherein an electrical resistivity of the insulating substrate is restricted to a range of 1 × 10 ⁻⁷ Ω · cm to 1 × 10 ⁻¹³ Ω · cm. A hollow sealing element characterized by comprising: 2. The hollow sealing element according to claim 1, wherein a through-hole for electrode connection is formed at a position facing the central portion of the internal electrode of the cover base, and a bonding interface with the internal electrode in a peripheral portion of the through-hole is formed. A hollow sealing element which is anodically bonded. The hollow sealing element according to claim 6, wherein an external electrode is formed in the through hole. The hollow sealing element according to any one of claims 1 to 7, wherein the functional part is composed of a pair of comb electrodes facing each other, and the hollow sealing element is a surface acoustic wave element. A hollow sealing element. A functional unit having a mechanically movable unit, an internal electrode that is electrically connected to the functional unit, and a sealing unit that surrounds the functional unit and the internal electrode as a set and a predetermined gap on the insulating substrate. Forming a large number of sets, and
A step of placing a cover base on the insulating base so as to be in contact with each set of internal electrode and sealing part, and forming a gap between each functional part and the cover base;
An anode electrode is in contact with the lower surface of the insulating substrate, a cathode electrode is in contact with the upper surface of the cover substrate, a voltage is applied between the anode electrode and the cathode electrode, and each internal electrode and the cover substrate are A step of anodic bonding the bonding interface and the bonding interface between each sealing portion and the cover base;
Removing the anode electrode and the cathode electrode, and dicing the cover base and the insulating base along the dicing lines in the gaps of the respective sets to separate them into individual hollow sealing elements. Manufacturing method of hollow sealing element. 10. The method of manufacturing a hollow sealing element according to claim 9, wherein the internal electrode is formed thicker than the functional part, the sealing part has substantially the same thickness as the internal electrode, and the cover base has the same thickness. A method for manufacturing a hollow sealing element, characterized by comprising a plate material having a thickness. 11. The method for manufacturing a hollow sealing element according to claim 9, wherein the cover base is made of glass. 12. The method for manufacturing a hollow sealing element according to claim 9, wherein the internal electrode and the sealing portion are made of a material mainly composed of aluminum. Manufacturing method. The method for manufacturing a hollow sealing element according to any one of claims 9 to 12, wherein an electrical resistivity of the insulating substrate is in a range of 1 × 10 ⁻⁷ Ω · cm to 1 × 10 ⁻¹³ Ω · cm. A method for producing a hollow sealing element, characterized by being regulated. The method for manufacturing a hollow sealing element according to claim 9, comprising a step of forming a through hole for electrode connection at a position facing the central portion of the internal electrode of the cover base after the anodic bonding step,
A method for manufacturing a hollow sealing element, characterized in that an anodic bonding portion remains at a bonding interface with an internal electrode in a peripheral portion of the through hole. The method for manufacturing a hollow sealing element according to claim 14, further comprising a step of forming an external electrode in the through hole after the through hole forming step. The method for manufacturing a hollow sealing element according to any one of claims 9 to 15, wherein the functional part is composed of a pair of comb electrodes facing each other, and the hollow sealing element is a surface acoustic wave element. A method for producing a hollow sealing element characterized by the above.

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