JP2008147895A - Crystal oscillator and its fabricating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive crystal oscillator with excellent vibration characteristics kept and with high reliable joining enabled. <P>SOLUTION: The crystal oscillator 1 has a vibrating arm 12 and a frame 13 surrounding a horizontal periphery of the vibrating arm 12. Further, the crystal oscillator 1 includes a crystal vibrating piece 11 provided with exciting electrodes 15a, 15b which are formed in front-back both sides of the vibrating arm 12 and are made of Au and with junction electrodes 16a, 16b extended from the exciting electrodes 15a, 15b to the front-back both sides of the frame 13, a first cover 21 formed with a junction metal film 25 on a plane opposed to the junction electrode 16a, and a second cover 31 formed with a junction metal film 35 on a plane opposed to the junction electrode 16b. Surfaces of the junction metal films 25, 35 of the first and second covers 21, 31 are subjected to chloridization. Then, the first cover 21, the crystal vibrating piece 11 and the second cover 31 are in solid contact. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a crystal resonator in which a lid and a crystal resonator element are packaged by solid bonding, and a method for manufacturing the crystal resonator.

  Conventionally, as a method of joining objects to be joined having metal joints, the joints are activated by an energy wave that is an atomic beam, an ion beam, or plasma, and then joined to each other. There is known a joining method in which a solid layer is joined at room temperature by combining and pressurizing (for example, see Patent Document 1).

  Further, a solid bonding method using chlorination treatment is also known as a method for activating the surface of an object to be bonded (see, for example, Patent Document 2).

JP-A-2005-311298 JP 2001-138075 A

  According to Patent Document 1, the surface of the joint is activated by an energy wave that is an atomic beam, an ion beam, or plasma to join the objects to be joined. Therefore, there is a problem that it is expensive.

  In addition, in the bonding method according to Patent Document 1 and Patent Document 2, both or one of the objects to be bonded is activated, but when applied to a crystal resonator having a CSP (chip size package) structure, an excitation electrode is used. When the activation process is performed, there is a problem that the vibration characteristics deteriorate.

  An object of the present invention is to solve the above-described problems, and to provide a low-cost crystal resonator capable of highly reliable bonding while maintaining good vibration characteristics, and a method for manufacturing the crystal resonator. Is to provide.

  The crystal resonator of the present invention includes a vibrating arm and a frame portion surrounding the periphery of the vibrating arm in the planar direction, and excitation electrodes made of Au are provided on both front and back surfaces of the vibrating arm, and the frame extends from the excitation electrode to the frame. A crystal vibrating piece provided with bonding electrodes extending on both the front and back surfaces of the part, a first lid having a bonding metal film on a surface facing the surface side of the bonding electrode, and facing the back surface side of the bonding electrode A second lid having a bonding metal film on a surface to be bonded, the surfaces of the bonding metal films of the first lid and the second lid being chlorinated, and the first lid The crystal vibrating piece and the second lid are solid-bonded.

  The crystal resonator of the present invention has a CSP (chip size package) structure in which crystal resonator elements are stacked so as to be sandwiched between a first lid and a second lid, and each is packaged by solid bonding. Here, by chlorinating the surface of the bonding metal film formed on the opposing surface (bonding surface) of the quartz lid of the first lid and the second lid, and activating the surface of the bonding metal film It is possible to provide a crystal resonator that achieves bonding with high bonding strength and high reliability.

  Further, since the chlorination treatment is performed only on the first lid body and the second lid body, there is no increase in the CI value due to the chlorination treatment in the crystal vibrating piece including the excitation electrode, and there is no deterioration in the vibration characteristics due to this. There is an effect.

  The bonding metal film is preferably formed of Cu or Ag.

  The material of the bonding electrode (continuous to the excitation electrode) formed on the crystal vibrating piece is Au, but the material of the bonding metal film formed on the first lid and the second lid is either Cu or Ag. Therefore, it is possible to provide a crystal resonator at a lower cost than the case where Au is used for both of the members to be joined as in Patent Document 1 described above.

  Here, when the bonding electrode is Cu, it is an inexpensive material, easy to form a film, and has an effect of increasing the shear strength of the bonding portion. Substitution of oxygen and chlorine is more easily performed than Cu (that is, chlorine is easily diffused on the surface of the bonding metal film), so that the surface of the bonding metal film is activated and the bonding strength can be further increased.

  The Vickers hardness of the bonding metal film is preferably 20 Hv or more and 180 Hv or less.

  When bonding the bonding electrode (Au) and the layer activated by the chlorination treatment on the surface of the bonding metal film to bond the base materials of the objects to be bonded, the bonding metal film has a high hardness. However, by setting the hardness of the bonding metal film to 20 Hv or more and 180 Hv or less, the contact area between the base materials of the bonding electrode and the bonding metal film can be increased, so that the bonding strength can be increased.

  Furthermore, the oxidation degree of the bonding metal film is more preferably pH 5.7 or less.

  Although details will be described in an embodiment described later, when the bonding metal film has a pH of 5.8 or more, activation of the bonding metal film surface does not proceed even if chlorination treatment is performed, so that sufficient bonding strength cannot be obtained. An experimental result was obtained that there was sufficient bonding strength when the pH was 5.7 or lower.

  The method for manufacturing a crystal resonator according to the present invention includes a vibrating arm, a frame portion that surrounds the periphery of the vibrating arm in a planar direction, an excitation electrode and a bonding electrode made of Au on the vibrating arm and the front and back surfaces of the frame portion, , A step of forming a first lid by chlorinating the surface of the bonding metal film formed to face the bonding electrode on the front surface side, and the bonding on the back surface side. A step of forming a second lid by chlorinating the surface of the bonding metal film formed to face the electrode, and laminating the first lid, the crystal vibrating piece, and the second lid in this order. And a joining step for joining.

  According to this manufacturing method, the bonding metal film surface formed on the opposing surfaces (bonding surfaces) of the first lid body and the crystal vibrating pieces of the second lid body is chlorinated to activate the bonding metal film surface. By doing so, the bonding strength is increased and a crystal resonator having high reliability is realized.

  Further, since the chlorination treatment is performed only on the first lid body and the second lid body, there is no increase in the CI value due to the chlorination treatment in the crystal vibrating piece including the excitation electrode, and there is no deterioration in the vibration characteristics due to this. There is an effect.

  Further, the chlorination treatment is performed by spraying chlorine gas on the bonding metal film of each of the first lid and the second lid, or bonding the first lid and the second lid to hydrochloric acid vapor. It is preferable to expose the metal film.

  By bringing chlorine gas or hydrochloric acid vapor into contact with the bonding metal film of each of the first lid and the second lid, chlorine that easily binds to the metal is present on the surface of the bonding metal film, and chlorine is present inside the bonding metal film. Since the metal bonds are diffused and cut, and the cut bonds are bonded to the bonding electrodes of the crystal vibrating piece, they can be bonded to each other in a solid state.

  Further, the amount and depth of chlorine to be taken in depend on the conditions of the chlorination treatment, and the main conditions include the concentration of chlorine gas or hydrochloric acid vapor and the treatment time, but these also have the effect that the conditions can be easily set.

  Moreover, it is preferable to perform the said chlorination process and the said joining process in an atmospheric pressure environment.

Since the chlorination treatment step is performed in an atmospheric pressure environment, a manufacturing facility such as a chamber for forming a vacuum or high pressure environment is unnecessary, and the chlorination treatment can be performed with an inexpensive facility.
Further, since the joining process is also performed in an atmospheric pressure environment, expensive equipment and equipment are not required for joining.

  Moreover, it is preferable that the said joining process is performed by heating and pressurizing the junction part of the said 1st cover body, the said quartz crystal vibrating piece, and the said 2nd lid body, and making each junction part mutually contact.

  By heating the joining portion, chlorine existing on the surface of the joining metal film of each of the first lid and the second lid becomes more active, and the time for solid joining can be shortened.

  In addition, since heating and pressurization are performed, the contact area of the bonding surface increases and bonding can be performed more easily, and the bonding strength increases.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a crystal resonator according to an embodiment of the present invention, FIGS. 2 to 5 show a method for manufacturing a crystal resonator, and FIG. 6 shows a shear strength of a bonded portion and an oxidation degree (pH value) of a bonded metal film. Shows the relationship.
Note that the drawings referred to in the following description are schematic views in which the vertical and horizontal scales of members or portions are different from actual ones for convenience of illustration.
(Crystal oscillator)

  FIG. 1 is a cross-sectional view showing a schematic structure of a crystal resonator according to an embodiment of the present invention. In FIG. 1, a crystal resonator 1 is formed by laminating a first lid 21 on the front surface (upper surface in the drawing) of a crystal vibrating piece 11 and a second lid 31 on the back surface (lower surface in the drawing). Each has a CSP structure in which they are solid-bonded.

  The crystal vibrating piece 11 has a vibrating arm 12 and a frame portion 13 surrounding the vibrating arm 12 at the center of the plane. Then, electrically independent excitation electrodes 15a and 15b are formed on both the front and back surfaces of the vibrating arm 12, and the excitation electrode 15a extends to the surface of the frame portion 13 and is continuous with the bonding electrode 16a. The excitation electrode 15b extends to the back surface of the frame portion 13 and is continuous with the bonding electrode 16b. Although not shown, a base film made of Cr or Au is formed between the excitation electrodes 15a and 15b, the bonding electrodes 16a and 16b, and the crystal vibrating piece 11 (that is, a crystal substrate).

  The first lid 21 is made of glass or a quartz substrate, and a cavity 22 in a range that does not contact the resonating arm 12 is formed in a substantially central portion. A base film 24 selected from Ti, Ni, Cr, NiCr or the like is formed on the outer peripheral surface of the cavity 22, and a bonding metal film 25 is formed on the surface of the base film 24. The bonding metal film 25 is selected from Cu and Ag. In this embodiment, a case where Cu is used will be described as an example. The surface of the bonding metal film 25 is subjected to a chlorination treatment to form an activated interface.

  The second lid 31 is made of glass or a quartz substrate, and a cavity 32 in a range not contacting the resonating arm 12 is formed at a substantially central portion. A base film 34 selected from Ti, Ni, Cr, NiCr or the like is formed on the outer peripheral surface of the cavity 32, and a bonding metal film 35 is formed on the surface of the base film 34. The bonding metal film 35 is selected from Cu and Ag. Hereinafter, in this embodiment, a case where Cu is used will be described as an example. The surface of the bonding metal film 25 is subjected to chlorination treatment to form an activated interface.

  A through hole 38 is formed in the cavity 32 of the second lid 31 so as to communicate between the inside and the outside. After the crystal resonator element 11, the first lid 21, and the second lid 31 are solid-bonded, the cavities 22 and 32 are formed. The inside air is evacuated and vacuumed, and then hermetically sealed by the sealing material 50.

  In addition, side through holes 37 are formed in the outer peripheral corners of the second lid 31, and connection electrodes 40 are formed to be connected via the bonding metal film 35 and the base film 34. External connection terminals 41 connected to the connection electrodes 40 are formed on the back surface of the second lid 31.

  Each element configured as described above is laminated in order of the second lid 31, the crystal vibrating piece 11, and the first lid 21 from below, and the frame portion 13 of the crystal vibrating piece 11 and the cavity of the second lid 31. The outer peripheral edge portion and the outer peripheral edge portion of the cavity of the first lid body 21 are accurately positioned and joined together by heat-pressing to form a packaged crystal resonator 1.

In such a crystal resonator 1, the vibrating arm 12 can freely vibrate in the cavities 22 and 32, and the cavities 22 and 32 are in a vacuum. The excitation electrodes 15 a and 15 b are connected to the external connection terminal 41 through the bonding electrodes 16 a and 16 b and the connection electrode 40. Although the illustration of the configuration of the excitation electrodes 15a and 15b and which external connection terminal 41 is connected is omitted, it may be arbitrarily selected in the design.
(Quartz crystal manufacturing method)

Next, a method for manufacturing a crystal resonator according to the above-described embodiment will be described with reference to the drawings. First, a method for manufacturing the first lid 21 will be described.
FIG. 2 is a partial cross-sectional view illustrating the method for manufacturing the first lid. In FIG. 2, a plurality of first lids 21 are simultaneously formed on a large glass substrate 20 (which may be a quartz substrate, sometimes referred to as a wafer), and are separated into pieces in a cutting process described later.

  First, as shown in FIG. 2A, a cavity 22 is formed on the back surface (lower surface in the figure) of the glass substrate 20. The cavity 22 is formed using wet etching or dry etching.

  Next, as shown in FIG. 2B, a base film 24 made of Cr is formed on the outer peripheral edge 23 of the cavity 22, and a bonding metal film 25 made of Cu is formed on the surface of the base film 24. As a material of the bonding metal film 25, Ag can be adopted in addition to Cu. The base film 24 is formed to improve the adhesion between the glass substrate 20 and the bonding metal film 25. Further, the hardness of the bonding metal film 25 is set to 20 Vv or more and 180 Hv or less in terms of Vickers hardness.

  A method of forming the base film 24 and the bonding metal film 25 on the entire back surface of the glass substrate 20 including the cavity 22 and then forming the base film 24 and the bonding metal film 25 into a predetermined pattern using a photolithography process can be employed.

  Subsequently, chlorine gas is blown onto the surface of the bonding metal film 25 or the surface of the bonding metal film 25 is exposed to hydrochloric acid vapor to perform chlorination treatment to form a chlorination layer 26 (see FIG. 2C). . When hydrochloric acid vapor is used, as an example, 35 mass% hydrochloric acid vapor may be exposed at room temperature for 30 seconds. In the case of chlorine gas as well, an activation layer sufficient for solid bonding can be obtained by spraying at room temperature for 30 seconds. The chlorination treatment is performed under an atmospheric pressure environment.

  In the chlorination treatment, chlorine gas or hydrochloric acid vapor is brought into contact with the bonding metal films 25 and 35 of the first lid body 21 and the second lid body 31, respectively, so that chlorine that easily binds to the metal is bonded to the bonding metal films 25 and 35. Since the chlorine is diffused into the bonding metal films 25 and 35 to break the metal bond and the cut bonds are bonded to the bonding electrodes 16a and 16b of the crystal vibrating piece 11, they are present in the solid state. Can be joined.

Then, the manufacturing method of the 2nd cover body 31 is demonstrated with reference to drawings.
FIG. 3 is a partial cross-sectional view illustrating a method for manufacturing the second lid. In FIG. 3, a plurality of second lids 31 are simultaneously formed on a large glass substrate 30 (which may be a quartz substrate, sometimes referred to as a wafer), and are separated into pieces in a cutting process described later.

  First, as shown in FIG. 3A, a cavity 32 is formed on the surface (upper surface in the figure) of the glass substrate 30. The cavity 32 is formed by wet etching or dry etching.

  Next, as shown in FIG. 3B, a through hole 38 and a side through hole 37 are formed. As a method for forming the through hole 38 and the side through hole 37, formation means such as wet etching, dry etching, sand blasting, or the like can be used.

  The through hole 38 is a hole for communicating the inside and outside of the cavity 32 and sealing the interior after the cavity is evacuated after solid joining, and a plurality of through holes 38 may be formed in the same cavity. The side through hole 37 is a hole for forming a connection electrode with the external connection terminal 41, and penetrates the glass substrate 30.

  Next, as shown in FIG. 3C, a base film 34 made of Ti, Ni, Cr, NiCr or the like is formed on the outer peripheral edge 33 of the cavity 32, and a bonding metal film made of Cu is formed on the surface of the base film 34. 35 is formed. As a material of the bonding metal film 35, Ag can be adopted in addition to Cu. Note that it is more preferable that the material of the bonding metal film 25 of the first lid 21 and the material of the bonding metal film 35 of the second lid 31 are the same because solid bonding can be performed under the same conditions. The bonding metal film 35 has a Vickers hardness of 20 Hv to 180 Hv.

  A method of forming the base film 34 and the bonding metal film 35 on the entire surface of the glass substrate 30 including the cavity 32 and then forming the base film 34 and the bonding metal film 35 into a predetermined pattern using a photolithography process can be employed.

  Subsequently, chlorination is performed by spraying chlorine gas on the surface of the bonding metal film 35 or exposing the surface of the bonding metal film 35 to hydrochloric acid vapor to form a chlorination layer 36 (see FIG. 3D). ). When hydrochloric acid vapor is used, as an example, 35 mass% hydrochloric acid vapor may be exposed at room temperature for 30 seconds. In the case of chlorine gas as well, an activation layer sufficient for solid bonding can be obtained by spraying at room temperature for 30 seconds. The chlorination treatment is performed under an atmospheric pressure environment. The chlorination treatment may be performed over the surfaces in the cavity 32, the through hole 38, and the side through hole 37.

Next, a method for manufacturing a quartz crystal vibrating piece will be described with reference to the drawings.
4A and 4B show a method for manufacturing a quartz crystal vibrating piece, in which FIG. 4A is a partial plan view, and FIG. First, as shown in FIG. 4A, a plurality of crystal vibrating pieces 11 are simultaneously formed on a large crystal substrate 10 (sometimes referred to as a crystal wafer), and are separated into pieces in a cutting process described later. .

  In the crystal vibrating piece 11, the outer shape of the vibrating arm 12 is formed by wet etching or dry etching. In FIG. 4A, the vibrating arm 12 represents a tuning fork type, but the shape of the vibrating arm is not limited to the tuning fork type. A hatched area surrounding the vibrating arm 12 is the frame portion 13.

  Subsequently, as shown in FIG. 4B, the Cr or Au base film 14 is formed on both the front and back surfaces of the quartz substrate 10, the excitation electrodes 15a and 15b made of Au are formed on the surface of the base film 14, and the bonding electrodes 16a and 16b. Form. The regions of the bonding electrodes 16a and 16b are more likely to be solid-bonded as they are softer, but it is more preferable to have a Vickers hardness of about 60 Hv.

Next, a crystal resonator bonding step and a subsequent manufacturing method will be described with reference to the drawings.
FIG. 5 is a partial cross-sectional view showing a method for manufacturing a crystal resonator according to the present embodiment.
First, the joining process will be described. As shown in FIG. 5 (a), a glass substrate 20 that forms a first lid with a bonded surface chlorinated and a glass substrate 30 that forms a second lid, and a quartz substrate that forms a quartz crystal resonator element. Collide with both 10 front and back sides. Then, in the atmosphere, the laminate 60 is formed by heating and pressurizing and solid-bonding. The joining conditions are a temperature of 200 ° C. to 300 ° C., a pressing force of 1 to 5 kgf / mm ² , and a pressing time of 1 minute to 5 minutes.

  By heating and pressurizing, chlorine on the chlorinated Cu surface diffuses into the Au layer of the bonding electrodes 16a and 16b of the quartz substrate 10 and the bonding metal films 25 and 35 (Cu layers) of the glass substrate 20 and the glass substrate 30. Then, both the Au layer and the Cu layer are activated, and the base materials of Au and Cu are bonded to each other, so that a good bonding strength can be obtained.

  In the bonding step, a method can be employed in which nitrogen gas is sprayed on the bonding surface to prevent the influence of Cu oxidation on the solid bonding.

  Further, in the joining process, the joining surfaces can be heated by applying ultrasonic pressure to promote efficient joining with a small applied pressure.

  At this time, the acidity of the chlorinated layers 26 and 36 before bonding is set to 5.7 or less in terms of pH value. The relationship between acidity and bonding strength will be described later with reference to FIG.

  Next, as shown in FIG. 5B, the connection electrode 40 is formed in the side through hole 37. At this time, a hole sealing electrode (not shown) is also formed on the inner surface of the through hole 38. For the connection electrode 40 and the hole sealing electrode, Cr, Ti, Ni, Al or the like is adopted. Then, the external connection terminal 41 is formed. The external connection terminal 41 may be formed in the same process as the connection electrode 40.

  Subsequently, as shown in FIG. 5C, the through hole 38 is sealed. The through-hole sealing is performed by inserting a low-melting-point metal material such as an AuGe ball or AuSn ball as the sealing material 50 into the through-hole 38 in a vacuum environment and then melting with a laser.

  Subsequently, as shown in FIG. 5D and the planar shape as shown in FIG. 5D, the laminated body 60 is cut by a cutting means such as dicing into pieces to form the crystal unit 1. The cutting is performed along a cutting line represented by a two-dot chain line in FIGS. 2, 3, and 4.

  As shown in FIG. 5E, the separated crystal resonator 1 has a CSP structure with a square plane (FIG. 5E is a plan view viewed from the second lid 31 side). The crystal unit 1 includes a vibrating arm 12 inside and is packaged with a first lid 21 and a second lid 31. The excitation electrodes 15a and 15b are connected to the external connection terminal 41 via the joining electrodes 16a and 16b and the connection electrode 40 (see also FIG. 1).

  Note that the entire surface of the separated crystal resonator 1 (excluding the range of the external connection terminal 41) may be coated with a fluororesin or the like. In this way, the strength of the package can be increased and the moisture-proof effect in the cavity can be enhanced.

Next, the relationship between the degree of oxidation of the bonding metal film and the bonding strength will be described with reference to the drawings.
FIG. 6 is a graph showing the relationship between the degree of oxidation of the bonding metal film and the bonding strength. In FIG. 6, the horizontal axis represents the degree of oxidation (pH), and the vertical axis represents the bonding strength (shear strength of the bonded portion). Note that the shear strength plotted in the graph represents an average value when a plurality of samples are measured.

As shown in FIG. 6, when the oxidation degree of the joining metal layers 25 and 35 is pH 5.8 or more, the shear strength is 0.5 kgf / mm ² or less, and when the pH is 6.0, the shear strength is close to 0 and is not joined. Indicates that exists. Further, the shear strength increases as the oxidation degree becomes lower than pH 5.6.

Here, it can be judged that there is a threshold value where the shear strength changes significantly between pH 5.6 and pH 5.8, and the degree of oxidation that can secure at least 0.5 kgf / mm ² or more of the shear strength is pH 5.7 or less. Can be predicted. For pH 4.5 or less, when connecting the plotted points in FIG. 6, it can be predicted that a shear strength of 2.5 kgf / mm ² or more can be secured. Therefore, if the oxidation degree of the bonding metal layers 25 and 35 is adjusted to pH 5.7 or less, sufficient bonding strength can be obtained.

  Therefore, according to the crystal resonator 1 and the method for manufacturing the crystal resonator according to the above-described embodiment, the crystal resonator 1 is formed by laminating the crystal resonator element 11 with the first lid body 21 and the second lid body 31. It is a CSP structure that is bonded and packaged, the surface of the bonding metal films 25 and 35 of the first lid 21 and the second lid 31 is chlorinated, and the surface is activated to increase the bonding strength, It is possible to provide a crystal resonator that realizes bonding with high reliability.

  Further, since the chlorination treatment is performed only on the first lid body 21 and the second lid body 31, the surface of the crystal vibrating piece 11 including the excitation electrodes 15 a and 15 b is not subjected to chlorination treatment. There is an effect that there is no increase in the vibration characteristic and there is no deterioration of the vibration characteristics due to this.

  The material of the bonding electrodes 16a and 16b formed on the crystal vibrating piece 11 is Au, but the material of the bonding metal films 25 and 35 formed on the first lid 21 and the second lid 31 is Cu or Ag. Therefore, it is possible to provide a crystal resonator at a lower cost than the case where Au is used as the material for both of the members to be joined as in Patent Document 1 described above.

  When the bonding metal films 25 and 35 are Cu, the material is inexpensive, the film formation is easy, and the shear strength of the bonding portion is increased. In the case of Ag, the bonding metal film surface is effective. The bonding strength can be further increased by easily replacing oxygen and chlorine in (diffusion of chlorine).

  Further, the Vickers hardness of the bonding metal films 25 and 35 is set to 20 Hv or more and 180 Hv or less. When the bonding electrodes 16a and 16b (material Au: hardness 60 HV) and the bonding metal films 25 and 35 (material Cu) are solid-bonded by softening the bonding metal films 25 and 35, an uneven surface with a small bonding interface. Therefore, the area of the bonding interface increases, a new surface appears at the bonding interface, and the bonding electrodes 16a and 16b and the bonding metal films 25 and 35 can be easily bonded.

Furthermore, by setting the oxidation degree of the bonding metal films 25 and 35 to pH 5.7 or less, a sufficient bonding strength with a shear strength of at least 0.5 kgf / mm ² can be obtained.

  Further, since the chlorination treatment step is performed in an atmospheric pressure environment, manufacturing equipment such as a chamber for forming a vacuum or high pressure environment is not required, and the chlorination treatment can be performed with an inexpensive facility.

  Furthermore, since the joining process is also performed in an atmospheric pressure environment, expensive manufacturing equipment and equipment such as a vacuum apparatus are not required for joining.

  The amount and depth of chlorine taken into the surfaces of the bonding metal films 25 and 35 by the chlorination treatment depend on the conditions of the chlorination treatment, and the main conditions include the concentration of chlorine gas or hydrochloric acid vapor and the treatment time. There is also an effect that setting is easy.

  In addition, the joining step is performed by heating and pressurizing the joint portions of the first lid body 21, the crystal vibrating piece 11, and the second lid body 31 to bring the joint portions into close contact with each other. By heating the bonding portion, chlorine existing on the surfaces of the bonding metal films 25 and 35 of the first lid body 21 and the second lid body 31 becomes more active, and the time for solid bonding can be shortened.

  In addition, since heating and pressurization are performed, the contact area of the bonding surface increases and bonding can be performed more easily, and the bonding strength increases.

  It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.

1 is a cross-sectional view showing a schematic structure of a crystal resonator according to an embodiment of the present invention. The fragmentary sectional view which shows the manufacturing method of the 1st cover which concerns on embodiment of this invention. The fragmentary sectional view which shows the manufacturing method of the 2nd cover which concerns on embodiment of this invention. The manufacturing method of the crystal vibrating piece which concerns on embodiment of this invention is shown, (a) is a fragmentary top view, (b) is a fragmentary sectional view which shows the AA cut surface of (a). FIG. 4 is a partial cross-sectional view illustrating a method for manufacturing a crystal resonator according to an embodiment of the present invention. The graph which shows the relationship between the oxidation degree of the joining metal film which concerns on embodiment of this invention, and joining strength.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Quartz crystal resonator, 11 ... Quartz vibrating piece, 12 ... Vibrating arm, 13 ... Frame part, 15a, 15b ... Excitation electrode, 16a, 16b ... Joining electrode, 21 ... 1st cover body, 31 ... 2nd cover body, 25, 35 ... Bonding metal film.

Claims (9)

An excitation electrode made of Au is provided on both front and back surfaces of the vibrating arm, and has a frame portion surrounding the periphery of the vibrating arm in the planar direction, and extends from the excitation electrode to both the front and back surfaces of the frame portion. A quartz crystal vibrating piece provided with a bonding electrode;
A first lid having a bonding metal film on a surface facing the surface side of the bonding electrode;
A second lid having a bonding metal film on the surface facing the back side of the bonding electrode,
The surface of the bonding metal film of each of the first lid and the second lid is chlorinated,
The crystal unit, wherein the first lid, the crystal vibrating piece, and the second lid are solid-bonded. The crystal resonator according to claim 1,
A crystal resonator, wherein the bonding metal film is made of Cu or Ag. The crystal unit according to claim 2,
A quartz resonator having a Vickers hardness of the bonding metal film of 20 Hv or more and 180 Hv or less. In the crystal unit according to any one of claims 1 to 3,
A crystal resonator, wherein the bonding metal film has an oxidation degree of pH 5.7 or less. Forming a crystal vibrating piece having a vibrating arm and a frame portion surrounding the periphery of the vibrating arm in a plane direction, and an excitation electrode and a bonding electrode made of Au on the vibrating arm and the front and back surfaces of the frame portion;
Forming a first lid by chlorinating the surface of the bonding metal film formed facing the bonding electrode on the surface side;
Forming a second lid by chlorinating the surface of the bonding metal film formed facing the bonding electrode on the back side;
A bonding step in which the first lid, the quartz crystal vibrating piece, and the second lid are stacked in order and solid-bonded;
A method of manufacturing a crystal resonator, comprising: In the manufacturing method of the crystal oscillator according to claim 5,
The method for manufacturing a crystal resonator, wherein the chlorination treatment is performed by spraying chlorine gas on a bonding metal film of each of the first lid and the second lid. In the manufacturing method of the crystal unit according to claim 5 or 6,
The chlorination treatment is performed by exposing each bonding metal film of the first lid and the second lid to hydrochloric acid vapor. In the manufacturing method of the crystal oscillator according to any one of claims 5 to 7,
A method for manufacturing a crystal resonator, wherein the chlorination treatment and the joining step are performed in an atmospheric pressure environment. In the manufacturing method of the crystal oscillator according to any one of claims 5 to 8,
The bonding step is performed by heating and pressurizing the bonding portions of the first lid, the quartz crystal vibrating piece, and the second lid to bring the bonding portions into close contact with each other. A method for manufacturing a vibrator.

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