JP5329105B2 - Manufacturing method of crystal unit - Google Patents

Description

The present invention relates to a method for manufacturing a quartz oscillator.

As shown in FIG. 9, a conventional crystal unit 512 includes a first substrate 504 having a first recess 501, a crystal resonator element 506, and a second recess 509 having an opening on one main surface. It is comprised from the formed 2nd board | substrate 510 which consists of flat glass or quartz. The first substrate 504 has a first recess 501 having an opening on one main surface, and a substantially wedge-shaped through hole 503. The substantially wedge-shaped through-hole 503 has a diameter that increases from one end on the first concave bottom surface 502 side toward the other end of the outer surface of the first substrate 504 made of flat glass or crystal. . Excitation electrodes 507 are formed on both main surfaces of the crystal resonator element 506. The crystal resonator element 506 is mounted on the first substrate 504. At this time, the extraction electrode of the crystal resonator element 506 is mounted so as to cover the through hole 503 of the first substrate 504. A metal film is previously applied to the surface of the first substrate 504 around the through hole 503 and the through hole 503. After mounting the first substrate 504 and the crystal resonator element 506, the conductive paste 515 closes the opening of the through hole 503 on the side where the crystal resonator element 506 is mounted. In this state, the first substrate 504 and the second substrate 510 are bonded to obtain the crystal resonator 512. (For example, see Patent Document 1)

The following prior art is disclosed about such a crystal resonator and a method for manufacturing the crystal resonator.
Japanese Patent Laid-Open No. 5-121985

  In addition to the prior art documents specified by the prior art document information described above, no prior art documents related to the present invention have been found by the time of filing of the present application.

  However, in a conventional crystal unit, the through-hole is filled with a conductive paste. However, sealing with such a conductive paste may result in non-uniform airtightness in individual crystal units. Will make you worse. In addition, if the airtightness is reduced, the characteristics of the crystal unit may be affected.

The present invention is intended to solve the above problems, therefore its object is to provide a method for producing a good crystal oscillator productivity improves airtightness.

In order to achieve the above object, the present invention provides a first substrate having a first recess, a through-hole in the first recess, a second substrate having a second recess, and a crystal piece. A quartz resonator element in which an excitation electrode and an extraction electrode are provided at predetermined positions on both main surfaces, and the extraction electrode provided on one main surface is routed to the other main surface through a through hole, and the crystal A structure including a metal buried portion that covers between the two lead electrodes routed to the other main surface of the vibration element and the through hole, and a plating layer that covers the metal buried portion and fills the through hole. A method of manufacturing a crystal resonator, wherein a plurality of the first recesses having openings on one main surface of the flat plate are formed at predetermined positions on a flat plate made of glass or quartz, and the first recess transmural on the opposite side of the principal surface or found the first recess and the one main surface of the opening of is provided Forming a first wafer member having a structure in which a plurality of the first substrates are continuously formed, and surrounding each first recess provided in the first wafer member. The side wall opening side end face and the crystal vibration element wafer frame integrally formed by connecting a plurality of the crystal vibration elements are directly joined, and the through-hole is embedded from the lead-out electrode to the through-hole. Forming a metal buried portion to be exposed, the surface of the metal buried portion exposed on the main surface opposite to the side on which the quartz crystal vibration element wafer is bonded of the first wafer member, and the exposure in the through hole Except for the surface of the first wafer member and the peripheral portion of the opening of the through hole on the main surface of the first wafer member opposite to the side to which the crystal resonator element wafer is bonded. The quartz crystal element on the side opposite to the main surface joined to the member The principal surface of the wafer, the crystal oscillation element wafer resist film is formed on the principal surface of the opposite side of the first wafer member to the side that is joined, said first wafer member and the quartz crystal vibrating element A wafer is immersed in an electrolytic plating solution, and a portion without the resist film is electroplated to form a plating layer, the resist film is removed, and one of the flat plates is placed at a predetermined position of a flat plate made of glass or quartz. by form a plurality of said second recess having an opening on the main surface, forming a second wafer member formed by continuous multiple of the second substrate structure, said second wafer member The side wall opening side end surface surrounding the second recess and the crystal resonator element wafer are directly bonded, and the second wafer member, the crystal resonator element wafer, and the first wafer member that are directly bonded Is divided at a predetermined position. Thus, the present invention is characterized in that the method is a method of manufacturing a crystal resonator in which crystal resonators are individually obtained.

According to the crystal resonator manufactured by the manufacturing method of the present invention, since the plating layer is formed on the outer surface of the metal embedded portion of the crystal resonator, the airtightness can be improved. Further, since the extraction electrode is not located on the bonding surface, the bonding becomes easy. Thereby, the productivity of the crystal unit can be improved.

  Further, according to the method for manufacturing a crystal resonator of the present invention, the crystal resonator outer surface of the metal embedded portion inside the through hole, and the crystal resonator outer surface of the metal embedded portion and the inside of the through hole of the metal embedded portion. Since the portion is covered with a plating material, the airtightness can be improved.

  Moreover, in order to manufacture a plurality of crystal resonators in a lump, there is no need to use a large number of carriers used in the manufacturing process of crystal resonators that are produced in individual containers. A crystal resonator with high reliability can be manufactured at a low production cost.

  Embodiments of the present invention will be described below with reference to the drawings. Each figure is exaggerated for easy understanding of the present invention.

(First embodiment)
FIG. 1 is a schematic perspective view of a crystal resonator according to an embodiment of the present invention. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a schematic partially enlarged view of FIG. FIG. 4 is a schematic perspective view of the crystal resonator element used in the crystal unit of the present invention as viewed from the other surface.

  The crystal resonator 100 of the present invention is mainly composed of a first substrate 10, a metal buried portion 15, a plating layer 16, a crystal resonator element 20 </ b> A, and a second substrate 30. The first substrate 10 is made of flat glass or crystal, and a first recess 14 having an opening is formed on one main surface of the first substrate 10. A through hole 12 is provided in the first concave bottom surface 11 </ b> A of the first substrate 10. The through-hole 12 has a substantially wedge shape in which an opening that faces the crystal resonator element 20A side when the first substrate 10 and the crystal resonator element 20A are joined increases in diameter toward the thickness direction of the first substrate 10. . The diameter of the through-hole 12 is about 60 μm at one end that is on the inner side of the crystal unit 20A, and about 140 μm at the other end that is on the outer side of the crystal unit 100. The length of is about 175 μm. In addition, two through holes 12 are provided in the first recess bottom surface 11A at positions corresponding to end portions of an extraction electrode 24A described later.

  The crystal resonator element 20A is formed in a quadrangular shape, and a quadrangular vibrating portion and a frame portion 22 surrounding the vibrating portion are integrally formed. The frame portion 22 is directly joined to the side wall portion opening side end surface 13 surrounding the first substrate 10 and the first recess 14. In the crystal resonator element 20A, excitation electrodes 23A having the same shape are formed on both main surfaces of the crystal piece. A lead electrode 24A is formed on the surface of the quartz resonator element 20A on the first recess 10 side. Although the shape of the extraction electrode 24 is not shown in FIG. 2, the extraction electrode 24 is an electrode connected to a part of the excitation electrode 23 and is a conduction path of an electrical output signal of the crystal resonator element 20 </ b> A. The lead electrode 24 is provided up to the end of the vibration portion 23 so as not to reach the frame portion 22 in a portion continuous with the frame portion 22. The lead electrode 24A facing the first substrate 10 and the lead electrode 24B on the opposite side are provided up to the opposite surface through a through hole provided in the crystal resonator element 20A. Therefore, the end portions of the respective extraction electrodes 24 are arranged on one main surface of the crystal piece as shown in FIG. Note that the through hole is preferably the same axis as the through hole 12 of the first substrate 10.

  The second substrate 30 is made of flat glass or crystal having a second recess 31 having an opening on one main surface. The side wall opening side end surface 32 surrounding the second recess 31 of the second substrate 30 and the surface opposite to the bonded surface of the first substrate 10 of the crystal resonator element 20A are directly bonded to each other to form the first recess 14. The second recess 31 is hermetically sealed.

  A metal buried portion 15 is formed in a gap between one end portion of the through-hole 12 provided in the first recess bottom surface 11A and the surface of the extraction electrode 24A of the crystal resonator element 20A facing the one end portion. Yes. The metal buried portion 15 is formed in the through hole 12 from the surface of the extraction electrode 24A. The metal burying portion 15 inside the through hole 12 is made of one of Cr, Cu, Ni, Au, and Sn, or two different kinds of metals.

  Further, a plating layer 16 is formed on a portion of the metal burying portion 15 exposed outside the crystal unit 100. The plating layer 16 may be provided up to a part of the periphery of the through hole 12 on the surface of the first substrate 10. The plated layer 16 serves to ensure hermetic sealing and to serve as an external terminal. As shown in FIG. 1, the surface shape of the through-hole 12 in which the plated layer 16 is formed on the outside of the crystal unit 100 is circular. In addition to the circular shape, it may be formed in a polygon such as a quadrangle, or may be formed in an elliptical shape. Further, the plating layer 16 is formed of any one of Cr, Cu, Ni, Au, Sn, or two different metals. The thickness of the plating layer 16 formed on the outer surface of the crystal unit 100 of the metal embedding portion 15 in FIGS. 2 and 3 may be, for example, about 5 μm to 50 μm.

  As shown in FIGS. 2 and 3, since the plating layer 16 is formed on the outer surface of the crystal unit 100 of the metal buried portion 15, a fine gap is formed between the inner surface of the through hole 12 and the metal buried portion 15. Even in the case of having a metal layer, the plated layer 16 is formed in the gap to increase the airtightness. As a result, the crystal resonator 100 having a highly reliable structure can be obtained.

  FIG. 8 is a schematic view showing the method of manufacturing the quartz crystal resonator according to the present invention step by step. Below, the manufacturing process of the crystal unit 12 of the present invention will be described in detail step by step.

  The first wafer member includes a plurality of plate-shaped glass or quartz crystals each having a first concave portion 14 and a through-hole 12 provided in each of the crystal resonator elements 20A constituting a crystal resonator element wafer described later. The first substrate 10 is formed in a continuous manner. First, as shown in FIG. 8A, the surface of the first wafer member opposite to the surface on which the opening of the first recess 14 is provided (hereinafter referred to as “one surface”). The through hole 12 is drilled. The through-hole 12 is formed by using sand blasting means as shown in FIG. 8A from the surface side opposite to the surface of the first wafer member where the opening of the first recess 14 is provided. . All the cross-sectional shapes of the through-holes 12 are small in the diameter of the opening of the first wafer member facing a quartz vibrating element wafer, which will be described later, and the diameter of the opening opposite to the side facing the quartz vibrating element wafer. Has a large wedge shape.

  Next, as shown in FIG. 8B, the side wall opening side end face 13 surrounding each first recess 14 provided in the first wafer member and the frame of the crystal resonator element wafer are directly joined. The crystal resonator element wafer is integrally formed by connecting a plurality of crystal resonator elements 20A. Excitation electrodes 23 having the same shape are formed on both main surfaces of each crystal resonator element 20A. The extraction electrode 24 connected to the excitation electrode 23 is formed at a position that fits in the first recess 14 and the second recess 31. The end portion of the extraction electrode 24 is provided up to a position facing the through hole 12. As shown in FIG. 8B, the end portion of the extraction electrode 24 </ b> A formed on one main surface of the crystal resonator element 20 </ b> A is provided at a position facing the through hole 12.

  Next, as shown in FIG. 8C, metal powder is sprayed from the one surface side of the first wafer member having the through holes 12 toward the inner surface of the through holes 12 by sandblasting means. As shown in FIG. 8C, when the metal powder is sprayed on the inner surface of the through hole 12, it melts by frictional heat generated by the collision with the inner surface of the through hole 12, and penetrates the surface of the extraction electrode 24A. The hole 12 is fixed while being deposited on the extraction electrode 24A so as to fill a gap between the hole 12 and one end. The metal powder deposited on the extraction electrode 24A of the crystal resonator element 20A fills the gaps described above, and further fills part of the through holes 12 to form the metal buried portion 15. Here, in addition to the method of blowing metal powder by sandblasting means and filling the gap between the surface of the extraction electrode 24A of the crystal resonator element 20A and the end of the through hole 12 with the metal burying portion 15, the metal is deposited by vacuum deposition or the like. A method of transferring to the through hole 12, a method of applying a conductive paste to the part of the through hole 12 using a bubble jet (registered trademark), or a method of applying the conductive paste into the through hole 12 by a printing method. A method may be used.

Subsequently, as shown in FIG. 8D , the surface of the metal buried portion 15 exposed on the main surface side opposite to the side on which the crystal vibration element wafer of the first wafer member is bonded, and the through hole 12. Except for the exposed surface of the first wafer member and the peripheral portion of the opening of the through hole 12 on the main surface of the first wafer member opposite to the side on which the crystal resonator element wafer is bonded. Resist film on the main surface of the crystal vibrating element wafer opposite to the main surface bonded to the member and the main surface of the first wafer member opposite to the side bonded to the crystal vibrating element wafer 17 is formed.

  The first wafer member and the crystal resonator element wafer bonded in this state are immersed in an electrolytic plating solution, and the surface where the resist film 17 is not present, that is, the surface exposed to the outside of the crystal unit 100 of the metal embedded portion 15 and the metal embedded. Electrolytic plating is applied to a portion between the surface of the portion 15 outside the crystal unit 100 and the inside of the through hole 12 of the metal burying portion 15, and then a plating layer 16 is formed as shown in FIG. As a result, an electrical conduction path from the surface of the extraction electrode 24A of the crystal resonator element 20A to the surface of the metal buried portion 15 is formed. Here, the plating uses a semi-additive method, a selective normal electrolytic plating, or the like. The plating process is performed so that the thickness of the plating layer 16 formed on the surface portion of the metal burying portion 15 is, for example, about 5 μm to 50 μm.

  Next, the resist film 17 is removed as shown in FIG.

  Next, as shown in FIG. 8 (g), the side wall portion opening side end surface 32 surrounding the second recess 31 of the second wafer member is directly bonded to the crystal resonator element wafer bonded to the first wafer member. Join. As a result, the excitation electrode 23 forming portion of the crystal resonator element 20A in which the metal burying portion 15 and the plating layer 16 are formed and the vicinity thereof are hermetically sealed together. The second wafer member is made of flat glass or crystal, and is provided with a second concave portion 31 facing each crystal resonator element 20A of the crystal resonator element wafer formed by connecting the crystal resonator elements 20A. Yes.

  For example, in this direct bonding, the bonding surface of the quartz-crystal vibrating element wafer (for example, W1) and the bonding surface of the first wafer member (for example, W2) are previously cleaned with an oxidizing liquid such as a sulfuric acid hydrogen peroxide mixture. The crystal vibrating element wafer (W1) is superposed on the bonded surface of the crystal vibrating element wafer (W1) and the bonded surface of the first wafer member (W2) in a state where the hydrophilic treatment is performed. And a first wafer member (W2) at the interface between the hydroxyl groups, hydrogen bonds between the hydroxyl groups occur, and the bonded state. Further, by directly bonding in an atmosphere of an inert gas that plays a role as an antioxidant gas such as nitrogen gas or argon gas, the metal constituting the excitation electrode 23A and the extraction electrode 24 even when bonded at normal pressure It is possible to prevent the film from being oxidized. Alternatively, direct bonding may be performed at room temperature. For example, in a state where Ar (argon) gas is jetted into the vacuum chamber, for example, activation by plasma generated by an ion gun activates the bonding surface of the crystal resonator element wafer (W1) and the first wafer member (W2). Then, the bonding surface of the quartz crystal vibration element wafer (W1) and the bonding surface of the first wafer member (W2) are superposed on each other to obtain a bonded state. In addition, the bonding strength between the crystal vibration element wafer (W1) and the base wafer (W2) can be increased by applying heat to the crystal vibration element wafer (W1) and the first wafer member (W2).

  Next, as shown in FIG. 8 (h), the second wafer member, the crystal resonator element wafer, and the first wafer member that are directly bonded are divided by using a scriber or the like at a predetermined position, and the crystal is individually separated. A vibrator 100 is obtained. According to the method for manufacturing the crystal unit 100 of the present invention, the outer surface of the crystal unit 100 in the metal embedded unit 15 inside the through hole 12, the surface of the metal unit 15 outside the crystal unit 100, and the metal unit Since the portion between the insides of the 15 through-holes 12 is covered with the plating material, the highly reliable crystal resonator 100 having the metal-embedded portion 15 with high airtightness can be manufactured.

  The crystal resonator element wafer bonded to the first wafer member is immersed in an electrolytic plating solution, so that the surface of the metal embedded portion 15, the surface of the metal embedded portion 15 outside the crystal unit 100, and the through hole of the metal embedded portion 15. 12, the step of electrolytically plating the portion between the inner side and forming the plating layer 16 is performed by directly bonding the side wall opening side end surface 32 surrounding the quartz resonator element wafer member and the second recess 31 of the second wafer member. It may be subsequent to the bonding step. Further, although the sand blasting means is used as the means for forming the through holes 12, wet etching means or dry etching means may be used instead of the sand blasting means.

  Since the method for manufacturing the crystal unit 100 is configured in this manner, the crystal unit 100 having the metal embedded portion 15 that fills the inside of the through hole 12 with significantly improved airtightness can be manufactured.

(Second embodiment)
FIG. 5 is a schematic perspective view showing an example of a crystal resonator element used in the crystal resonator according to the second embodiment. As shown in FIG. 5, the crystal resonator element 20A in FIG. 4 is different from the first embodiment in that the shape of the crystal resonator element 20A is a single plate like 20B and does not have a vibrating portion and a frame portion surrounding it.

  The crystal resonator element 20B includes an excitation electrode 23A and a lead electrode 24 on both main surfaces. The extraction electrode 24B provided on the one main surface is extracted to the other end through a through hole separated from the excitation electrode 23A to the extent that it does not reach the first substrate 10. Therefore, the end portions of the respective extraction electrodes 24 are arranged on the other main surface of the crystal resonator element 20B as in 24A and 24B of FIG. Also in the second embodiment, since the plating layer 16 is formed on the outer surface of the metal buried portion 15 of the crystal unit 100, there is a fine gap between the inner surface of the through hole 12 and the metal buried portion 15. Even in this case, the plated layer 16 is formed in the gap to increase the airtightness. As a result, the crystal resonator 100 having a highly reliable structure can be obtained.

(Third embodiment)
FIG. 6 is a perspective view showing an example of a crystal resonator element used in the vibrator according to the third embodiment of the present invention. FIG. 6 shows a case where the crystal resonator element 20C has a tuning fork shape.
This crystal resonator element 20C includes an excitation electrode 23B and a lead electrode 24 on both main surfaces. The lead electrode 24B provided on one main surface is drawn to the other end through a through hole formed at a position away from the excitation electrode 23B to the extent that it does not reach the first substrate 10. Accordingly, the end portions of the respective extraction electrodes 24 are arranged on the other main surface of the crystal resonator element 20C as in the case of the extraction electrodes 24A and 24B in FIG. Even when the crystal resonator element 20 </ b> C has these shapes, the plating layer 16 is formed on the outer surface of the metal embedded portion 15 of the crystal resonator 100, so that the space between the inner surface of the through-hole 12 and the metal embedded portion 15 is formed. Even if there are fine gaps, the plated layer 16 is formed in the gaps to increase the airtightness. As a result, the same effect as in the first embodiment can be obtained, in which the crystal resonator 100 having a highly reliable structure can be obtained. .

(Fourth embodiment)
FIG. 7 is a perspective view showing an example of a crystal resonator element used in the vibrator according to the fourth embodiment of the present invention. FIG. 7 shows a case where the shape of the crystal resonator element 20D is an inverted mesa type. The crystal resonator element 20D includes an excitation electrode 23C and a lead electrode 24 on both main surfaces. The lead electrode 24B provided on the one main surface is drawn to the other end through a through hole formed at a position away from the excitation electrode 23C to the extent that it does not reach the first substrate 10. Accordingly, the end portions of the respective extraction electrodes 24 are arranged on the other main surface of the crystal resonator element 20D like the extraction electrodes 24A and 24B in FIG. Thus, even when the crystal resonator element 20D has these shapes, since the plating layer 16 is formed on the outer surface of the metal embedded portion 15 of the crystal unit 100, the inner surface of the through hole 12 and the metal embedded portion are formed. Even if there is a fine gap between 15, the plating layer 16 is formed in the gap to increase the airtightness, and as a result, the crystal resonator 100 having a highly reliable structure can be obtained as in the first embodiment. There is an effect.

1 is a schematic perspective view of a crystal resonator according to an embodiment of the present invention. It is AA sectional drawing of the outline of FIG. FIG. 3 is a schematic partially enlarged view of FIG. 2. It is the schematic perspective view which looked at the crystal resonator element used for the crystal unit of the present invention from the other side. It is a schematic perspective view which shows an example of the crystal oscillation element used for the crystal resonator which concerns on 2nd embodiment of this invention. It is a schematic perspective view which shows an example of the crystal oscillation element used for the vibrator | oscillator by 3rd embodiment of this invention. It is a schematic perspective view which shows an example of the crystal oscillation element used for the vibrator | oscillator by 4th embodiment of this invention. It is the schematic diagram which followed the process for the manufacturing method of the crystal oscillator of this invention. It is a schematic sectional drawing which shows the conventional quartz oscillator.

Explanation of symbols

14 1st recessed part 11A 1st recessed part bottom face 12 Through-hole 10 1st board | substrate 13 Side wall part opening side end surface 20A, 20B, 20C, 20D surrounding a 1st recessed part Crystal vibrating element 22, 22A Frame part 23A, 23B, 23C , 23D Excitation electrodes 24, 24A, 24B Lead electrode 31 Second recess 30 Second substrate 32 Side wall opening side end surface surrounding second recess 100 Crystal resonator 15 Metal buried portion 16 Plating layer 17 Resist film

Claims (1)

A first substrate having a first recess and having a through hole in the first recess, a second substrate having a second recess, and an excitation electrode and a lead at predetermined positions on both main surfaces of the crystal piece An electrode is provided, and the lead electrode provided on one main surface is routed to the other main surface of the crystal resonator element by being routed to the other main surface through a through hole. A method of manufacturing a crystal resonator having a metal buried portion that covers between the two extraction electrodes and the through hole, and a plating layer that covers the metal buried portion and fills the through hole ,
A plurality of the first concave portions having openings on one main surface of the flat plate are formed at predetermined positions on the flat plate made of glass or quartz, and the one of the first concave portions provided with the opening is provided. By drilling a through-hole penetrating into the first recess from the main surface opposite to the main surface, a first wafer member having a structure in which a plurality of the first substrates are continuously formed is formed.
A side wall opening side end surface surrounding each of the first recesses provided on the first wafer member and a frame of the crystal resonator element wafer formed by integrating a plurality of the crystal resonator elements are directly bonded. ,
In the through hole, a metal buried portion is formed to bury from the lead electrode to the inside of the through hole,
A surface of the metal buried portion exposed on a main surface opposite to a side to which the crystal vibration element wafer is bonded of the first wafer member; an exposed surface in the through hole; Main surface bonded to the first wafer member, except for the peripheral portion of the opening of the through hole in the main surface on the opposite side of the main surface to which the quartz crystal vibration element wafer is bonded. Forming a resist film on the main surface of the quartz crystal vibration element wafer on the opposite side to the main surface of the first wafer member on the opposite side to the side on which the crystal vibration element wafer is bonded,
Immerse the first wafer member and the quartz crystal vibration element wafer in an electrolytic plating solution, and perform electrolytic plating on a portion without the resist film to form a plating layer;
Removing the resist film;
A structure in which a plurality of the second substrates are formed by forming a plurality of the second recesses having openings on one main surface of the flat plate at a predetermined position of a flat plate made of glass or quartz. Forming a second wafer member of the second wafer member, and joining the quartz crystal resonator element wafer to the side wall opening side end surface surrounding the second recess of the second wafer member by direct bonding,
A crystal resonator manufacturing method , wherein the directly bonded second wafer member, the crystal resonator element wafer, and the first wafer member are individually divided at predetermined positions to individually obtain a crystal resonator. Way .

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