Method for manufacturing a piezoelectric vibration device, piezoelectric vibration device, and sheet substrate

Abstract

Provided is a method for manufacturing a piezoelectric vibration device using a sheet substrate, the device making it possible to measure the properties of piezoelectric vibration pieces on an individual basis. This manufacturing method manufactures a plurality of piezoelectric vibration devices using a sheet substrate 1 in which a plurality of bases 10 accommodating piezoelectric pieces are continuous in a matrix pattern and integrally molded. External connection terminals 61-64 including a pair of first and second external connection terminals 61, 62 for piezoelectric vibration pieces are formed on the outer bottom surface of the base 10, and on the outer bottom surface of the sheet substrate 1, the first external connection terminal 61 of the base 10 is electrically connected to the third external connection terminal 63 of the base 10 on the right side adjacent to said base 10. The manufacturing method includes a cutting step for cutting the electrical connection between the first external connection terminal 61 and the third external connection terminal 63 on the sheet substrate 1 by means of energy beams.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a piezoelectric vibration device for manufacturing a piezoelectric vibration device, a piezoelectric vibration device manufactured by the manufacturing method, and a sheet substrate used in the manufacturing method.

Background Art

[0002] A piezoelectric vibration device generally includes a container-shaped base made of an insulator with an open top, a piezoelectric vibration piece held in the internal space of the base by a conductive adhesive or the like, and a lid joined to the upper edge portion of the base so as to seal the internal space of the base covering the piezoelectric vibration piece. Further, mounting pads to which the piezoelectric vibration piece is electrically connected are provided on the inner bottom surface of the base, and external connection terminals connected to the mounting pads are provided on the outer bottom surface of the base. A sealing metal for welding the lid is provided on the upper edge portion of the base (see, for example, Patent Document 1). Generally, the mounting pads, the external connection terminals, and the sealing metal are subjected to gold plating or the like to prevent oxidation.

[0003] By the way, as an example of a method for manufacturing this type of piezoelectric vibration device, there is a method in which piezoelectric vibration pieces are sequentially mounted on individually independent bases, and then lids are joined to the upper edge portions of the respective bases. However, in this manufacturing method, there is a limit to the number of crystal oscillators that can be manufactured per unit time, and it is difficult to achieve high production efficiency.

[0004] As a method for solving this problem, a large number of recesses are formed in a matrix shape on the upper surface of a sheet substrate, and piezoelectric vibration devices are simultaneously mounted in the respective recesses (see, for example, Patent Document 2). That is, by taking a large number of bases on the sheet substrate, the production efficiency is improved.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, in manufacturing methods where multiple bases are molded from a sheet substrate, electrodes and other components are plated with gold or similar materials. Electroplating is a plating method used to obtain an appropriate plating thickness, but when using this method, all metal parts (undercoat metals) in the area to be plated must be electrically conductive. Therefore, when a frequency measuring device is connected to individual piezoelectric vibrators to perform frequency measurements, other piezoelectric vibrators electrically connected to the target piezoelectric vibrator will conduct electricity and affect its operation, making it impossible to measure the frequency of only the target piezoelectric vibrator.

[0007] In view of the above problems, the present invention aims to provide a method for manufacturing a piezoelectric vibration device in which a large number of bases for housing at least piezoelectric vibrating pieces are cut on a sheet substrate, the method for manufacturing a piezoelectric vibration device that enables the measurement of the characteristics of each piezoelectric vibrating piece individually, a piezoelectric vibration device manufactured by the manufacturing method, and a sheet substrate used in the manufacturing method. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides a method for manufacturing a piezoelectric vibration device, which involves manufacturing a plurality of piezoelectric vibration devices using a sheet substrate in which a plurality of rectangular bases, each having a plan view, are integrally molded in a matrix, and each base is arranged in such a matrix that at least contains a piezoelectric vibration piece. Each of the bases has a plurality of external connection terminals formed on its outer bottom surface, including a pair of external connection terminals for piezoelectric vibration pieces, for electrically connecting the piezoelectric vibration piece housed in the base to the outside of the base. On the outer bottom surface of the sheet substrate, one of the pair of external connection terminals for piezoelectric vibration pieces of a predetermined base among the plurality of bases is electrically connected to a first external connection terminal of a first base adjacent to the predetermined base among the plurality of bases. The method for manufacturing a piezoelectric vibration device is characterized by having a cutting step in the sheet substrate, in which the electrical connection between the one external connection terminal for piezoelectric vibration piece and the first external connection terminal is cut using a cutting device, thereby electrically separating the one external connection terminal for piezoelectric vibration piece from the first external connection terminal.

[0009] In this configuration, one external connection terminal for a piezoelectric vibrator on a predetermined base is electrically connected to the first external connection terminal of a first base adjacent to the predetermined base in order to perform plating. Furthermore, in the cutting process, the electrical connection between the one external connection terminal for the piezoelectric vibrator and the first external connection terminal is severed using a cutting device, thereby making the one external connection terminal for the piezoelectric vibrator electrically independent. As a result, even in a sheet substrate in which multiple bases are integrally connected, the characteristics of the piezoelectric vibration device can be measured while suppressing the influence of other bases by contacting each of the pair of external connection terminals for piezoelectric vibrators that are electrically connected to the piezoelectric vibrator on each base with a measuring probe.

[0010] Furthermore, on the outer bottom surface of the sheet substrate, the other external connection terminal for the piezoelectric vibrator of the pair of external connection terminals for the piezoelectric vibrator of the predetermined base is not electrically connected to any of the multiple external connection terminals of any of the bases adjacent to the predetermined base among the multiple bases.

[0011] With this configuration, only one external connection terminal for the piezoelectric vibrator is electrically connected to the first external connection terminal of the adjacent first base, thus minimizing the area to be cut by the cutting device during the cutting process.

[0012] Furthermore, on the outer bottom surface of the sheet substrate, the other external connection terminal for a piezoelectric vibrator of a pair of external connection terminals for a piezoelectric vibrator of a predetermined base among the plurality of bases is electrically connected to the second external connection terminal of a second base adjacent to the predetermined base among the plurality of bases. In the cutting process, the electrical connection between the other external connection terminal for a piezoelectric vibrator and the second external connection terminal is severed using a cutting device, thereby electrically isolating the other external connection terminal for a piezoelectric vibrator from the second external connection terminal.

[0013] In this configuration, the external connection terminal for the piezoelectric vibrator on the other base of a predetermined base is electrically connected to the second external connection terminal of a second base adjacent to the predetermined base in order to apply plating. Furthermore, in the cutting process, the electrical connection between the other external connection terminal for the piezoelectric vibrator and the second external connection terminal is severed using a cutting device, thereby making the other external connection terminal for the piezoelectric vibrator electrically independent. This allows for efficient electroplating of the electrically connected pair of external connection terminals for the piezoelectric vibrator and multiple external connection terminals. Moreover, since the electrical connection between the external connection terminals is severed in the cutting process, the characteristics of the piezoelectric vibration device can be measured while suppressing the influence of other bases by bringing a measuring probe into contact with each of the pair of external connection terminals for the piezoelectric vibrator that are electrically connected to the piezoelectric vibrator on the base of a sheet substrate in which multiple bases are arranged in a matrix.

[0014] Furthermore, each of the plurality of external connection terminals relating to each of the bases is formed spaced inward from the outer edge of the outer bottom surface of the base in a plan view, and a connection portion is formed on the outer bottom surface of the sheet substrate that straddles the boundary between the predetermined base and the first base, and electrically connects one of the pair of external connection terminals for piezoelectric vibrators of the predetermined base to the first external connection terminal of the first base by physically connecting them.

[0015] Furthermore, each of the plurality of external connection terminals relating to each of the bases is formed spaced inward from the outer edge of the outer bottom surface of the base in a plan view. On the outer bottom surface of the sheet substrate, a first connection portion is formed, which straddles the boundary between the predetermined base and the first base, and electrically connects one of the pair of external connection terminals for piezoelectric vibrators of the predetermined base to the first external connection terminal of the first base by physically connecting them. A second connection portion is formed, which straddles the boundary between the predetermined base and the second base, and electrically connects the other of the pair of external connection terminals for piezoelectric vibrators of the predetermined base to the second external connection terminal of the second base by physically connecting them.

[0016] Incidentally, the metal film forming the external connection terminals is usually constructed by laminating a plating layer onto a metallized layer that serves as the underlying metal layer. If each of the multiple external connection terminals is not spaced inward relative to the outer edge of the base's bottom surface in a plan view, then when the boundary between a predetermined base and a first base is cut by a cutting device (such as a laser beam device or dicing blade device), the plating layer at that boundary of the external connection terminal will be scraped off. When the plating layer is scraped off, the underlying metal layer that was covered by the plating layer is exposed to the outside, which may be undesirable in terms of environmental resistance depending on the type of underlying metal layer.

[0017] With this configuration, each of the multiple external connection terminals is formed spaced inward from the outer edge of the outer bottom surface in a plan view, thus eliminating interference between the cutting device and the external connection terminals and preventing the occurrence of the above-mentioned problems.

[0018] Furthermore, the outer bottom surface of the sheet substrate may not have a connection portion formed that straddles the boundary between the predetermined base and any of the multiple bases adjacent to the predetermined base, thereby electrically connecting the other external connection terminal for the piezoelectric vibrator of the pair of external connection terminals for the piezoelectric vibrator of the predetermined base with any of the multiple external connection terminals of the base in question.

[0019] With this configuration, since only one external connection terminal for the piezoelectric vibrator is provided with a connection portion for electrically connecting that external connection terminal for the piezoelectric vibrator to the first external connection terminal of the adjacent first base, the area to be cut by the cutting device during the cutting process can be minimized.

[0020] Furthermore, the sheet substrate is a laminate having a plurality of layers, including a layer on its outer bottom surface in which the plurality of external connection terminals of each of the bases are formed, and one or more layers laminated on the side of the layer opposite to the outer bottom surface, and a wiring pattern is formed between the laminates of the plurality of layers, straddling the boundary between the predetermined base and the base adjacent to that predetermined base.

[0021] With this configuration, a wiring pattern is formed between the laminations of multiple layers, spanning the boundaries between a predetermined base, multiple bases, and adjacent bases, allowing for the simultaneous deposition of multiple external connection terminals by electroplating.

[0022] Further, the sheet substrate is a laminate having a plurality of layers including a layer in which the plurality of external connection terminals of each of the bases are formed on the outer bottom surface thereof, and one or more layers laminated on the surface of the layer opposite to the outer bottom surface, and a wiring pattern is formed between the layers of the plurality of layers across the boundary between the predetermined base and the base adjacent to the predetermined base among the plurality of bases. One of the external connection terminals for a pair of piezoelectric vibrating pieces of the predetermined base is electrically connected to the first external connection terminal of the first base by the connection portion, and the other external connection terminal for a pair of piezoelectric vibrating pieces of the predetermined base may be electrically connected to the second external connection terminal among the plurality of external connection terminals of the second base adjacent to the predetermined base among the plurality of bases by the wiring pattern.

[0023] According to this configuration, one external connection terminal for a piezoelectric vibrating piece is connected to the first external connection terminal via the connection portion, and the other external connection terminal for a piezoelectric vibrating piece is electrically connected to the second external connection terminal via the wiring pattern. Therefore, a plurality of external connection terminals can be formed in a batch by the electrolytic plating method.

[0024] Further, the cutting step may physically cut at least the connection portion along the boundary between the predetermined base and the first base.

[0025] According to this configuration, at least the connection portion is physically cut along the boundary between the predetermined base and the first base, so that the connection between one external connection terminal for a piezoelectric vibrating piece of the predetermined base and the first external connection terminal of the first base can be surely severed. Further, by thinning or cutting the portion of the boundary including the connection portion along the boundary between the predetermined base and the first base, the sheet substrate can be divided into a plurality of piezoelectric vibration devices and electrically cut simultaneously.

[0026] Further, the cutting device may be an energy beam generator.

[0027] According to this configuration, for example, by using a device that uses an energy beam such as a laser beam as a cutting means, compared to the case of using a blade as in blade dicing, there are the following advantages. There is no need to replace components corresponding to blade replacement due to blade wear or the like, and the production efficiency is excellent. Also, the cutting cost can be reduced compared to blade dicing, and as a result, the number of piezoelectric vibration devices that can be obtained from a single sheet substrate increases. Further, by using a device that cuts with an energy beam such as a laser beam as a cutting device, cutting can be reliably performed even in a minute area.

[0028] Further, the piezoelectric vibration device according to the present invention is characterized by being manufactured by the above-described method for manufacturing a piezoelectric vibration device.

[0029] According to this configuration, since the characteristics of individual piezoelectric vibration devices can be measured in a state where a plurality of piezoelectric vibration devices are connected in series, a piezoelectric vibration device with excellent characteristics can be obtained.

[0030] Further, the sheet substrate according to the present invention is a sheet substrate in which a plurality of rectangular bases in plan view for accommodating at least piezoelectric vibration pieces are integrally formed in a matrix, and on the outer bottom surface of each of the bases, a plurality of external connection terminals including a pair of external connection terminals for piezoelectric vibration pieces for electrically connecting the piezoelectric vibration piece accommodated in the base to the outside of the base are formed. On the outer bottom surface of the sheet substrate, one of the pair of external connection terminals for piezoelectric vibration pieces of a predetermined base among the plurality of bases is electrically connected to a first external connection terminal among the plurality of external connection terminals of a first base adjacent to the predetermined base among the plurality of bases.

[0031] In this configuration, one external connection terminal for a piezoelectric vibrator is electrically connected to a first external connection terminal among multiple external connection terminals of a first base adjacent to a predetermined base among multiple bases, so that multiple external connection terminals can be efficiently plated. Furthermore, by disconnecting the electrical connection between one external connection terminal for a piezoelectric vibrator and the first external connection terminal, a pair of external connection terminals for piezoelectric vibrators become electrically independent on a sheet substrate in which multiple bases are connected, making it possible to measure the characteristics of individual piezoelectric vibration devices.

[0032] Furthermore, in the sheet substrate according to the present invention, on the outer bottom surface of the sheet substrate, the other external connection terminal for a pair of external connection terminals for a piezoelectric vibrator on a predetermined base among the plurality of bases is electrically connected to a second external connection terminal of a second base adjacent to the predetermined base among the plurality of bases.

[0033] In this configuration, the other external connection terminal for the piezoelectric vibrator is electrically connected to the second external connection terminal of the second base adjacent to a predetermined base among the multiple bases, so that the multiple external connection terminals can be efficiently plated. Furthermore, by disconnecting the electrical connection between the other external connection terminal for the piezoelectric vibrator and the second external connection terminal, the pair of external connection terminals for piezoelectric vibrators become electrically independent in a sheet substrate with multiple bases connected together, making it possible to measure the characteristics of each piezoelectric vibrator device. [Effects of the Invention]

[0034] According to the present invention, in the cutting process, the electrical connection between one external connection terminal for a piezoelectric vibrator on a predetermined base and the first external connection terminal on a first base adjacent to the predetermined base is cut using a cutting device, thereby electrically isolating the said external connection terminal for the piezoelectric vibrator. As a result, even in a sheet substrate in which multiple bases are integrally connected, the characteristics of the piezoelectric vibration device can be measured while suppressing the influence of other bases by contacting each of the pair of external connection terminals for piezoelectric vibrators that are electrically connected to the piezoelectric vibrator on each base with a measuring probe. [Brief explanation of the drawing]

[0035] [Figure 1] This is a schematic plan view of the upper surface of a sheet substrate according to Embodiment 1 of the present invention. [Figure 2] Figure 1 is a schematic plan view (perspective view) of the underside of the sheet substrate. [Figure 3] Figure 1 is a schematic cross-sectional view of the sheet substrate. [Figure 4] This is a schematic plan view of the upper surface of the first ceramic layer that constitutes the sheet substrate in Figure 1. [Figure 5] This is a schematic plan view of the upper surface of the second ceramic layer that constitutes the sheet substrate in Figure 1. [Figure 6] Figure 1 is a schematic plan view (perspective view) of the underside of the second ceramic layer that constitutes the sheet substrate. [Figure 7] This is a schematic plan view of the upper surface of the third ceramic layer that constitutes the sheet substrate in Figure 1. [Figure 8] (a) is a schematic plan view (perspective view) of the underside of the third ceramic layer that constitutes the sheet substrate in Figure 1. (b) is a partially enlarged view. [Figure 9] This is a schematic cross-sectional view of a piezoelectric vibration device according to Embodiment 1 of the present invention. [Figure 10] This is a schematic plan view of the upper surface of the second ceramic layer constituting the sheet substrate in a modified example of Embodiment 1 of the present invention. [Figure 11]This is a schematic plan view (perspective view) of the lower surface side of the second ceramic layer constituting the sheet substrate in a modified example of Embodiment 1 of the present invention. [Figure 12] This is a schematic plan view (perspective view) of the lower surface side of the third ceramic layer constituting the sheet substrate in a modified example of Embodiment 1 of the present invention. [Figure 13] This is a schematic cross-sectional view of a piezoelectric vibration device according to a modified example of Embodiment 1 of the present invention. [Modes for carrying out the invention]

[0036] [Embodiment 1] Hereinafter, a method for manufacturing a piezoelectric vibration device according to Embodiment 1 of the present invention, a piezoelectric vibration device manufactured by said manufacturing method, and a sheet substrate used in said manufacturing method will be described with reference to the drawings.

[0037] First, the configuration of the sheet substrate 1 will be described with reference to Figures 1 to 8. Figure 1 is a schematic plan view of the top surface of the sheet substrate 1 according to this embodiment. Figure 2 is a schematic plan view (perspective view) of the bottom surface of the sheet substrate 1 of Figure 1. Figure 3 is a schematic cross-sectional view of the sheet substrate 1 of Figure 1. Figure 4 is a schematic plan view of the top surface of the first ceramic layer 11 constituting the sheet substrate 1 of Figure 1. Figure 5 is a schematic plan view of the top surface of the second ceramic layer 12 constituting the sheet substrate 1 of Figure 1, and Figure 6 is a schematic plan view (perspective view) of the bottom surface of the second ceramic layer 12 constituting the sheet substrate 1 of Figure 1. Figure 7 is a schematic plan view of the top surface of the third ceramic layer 13 constituting the sheet substrate 1 of Figure 1, and Figure 8 is a schematic plan view (perspective view) of the bottom surface of the third ceramic layer 13 constituting the sheet substrate 1 of Figure 1. Note that the same letters [A], [B], [C], and [D] in Figures 1 to 2 and Figures 4 to 8 are included to facilitate understanding of the corresponding positions in Figures 4 to 8. In Figures 1 to 2 and Figures 4 to 8, [A] is shown in the corresponding position in a plan view, [B] is shown in the corresponding position in a plan view, [C] is shown in the corresponding position in a plan view, and [D] is shown in the corresponding position in a plan view. Note that in Figures 1 to 8, the multiple bases 10 formed in a matrix on the sheet substrate 1 have the same structure, and the numbering is omitted in some parts in Figures 1 to 8.

[0038] The sheet substrate 1 is a sheet substrate integrally molded by connecting multiple rectangular bases 10 in a matrix. As shown in Figure 3, the sheet substrate 1 is a ceramic laminate consisting of three layers, including a first ceramic layer 11, a second ceramic layer 12, and a third ceramic layer 13 made of a ceramic material such as alumina. The sheet substrate 1 is laminated in the order of the third ceramic layer 13, the second ceramic layer 12, and the first ceramic layer 11.

[0039] The second ceramic layer 12 has a rectangular, flat shape in plan view. The first ceramic layer 11 has a rectangular outer perimeter in plan view, and rectangular through-holes 16 are formed in a matrix in plan view. Although Figures 1 and 4 show the through-holes 16 arranged in a 3x3 matrix, the matrix may be other. The third ceramic layer 13 has a rectangular outer perimeter in plan view, and rectangular through-holes 17 are formed in a matrix in plan view. Although Figures 2, 7 and 8 show the through-holes 17 arranged in a 3x3 matrix, the matrix may be other. In plan view, the centers of the through-holes 16 formed in the first ceramic layer 11 and the centers of the through-holes 17 formed in the third ceramic layer approximately overlap. Also, in plan view, the formation area of ​​the through-holes 16 is larger than the formation area of ​​the through-holes 17, and the formation area of ​​the through-holes 17 is completely contained within the formation area of ​​the through-holes 16.

[0040] On the upper surface of the first ceramic layer 11, a groove 11A parallel to the long side along [A]-[B] is formed, and a groove 11B parallel to the short side along [B]-[C] is formed. Also, on the lower surface of the third ceramic layer 13, a groove 13B parallel to the long side along [A]-[B] is formed. In a plan view, the groove 11A formed on the upper surface of the first ceramic layer 11 and the groove 13B formed on the third ceramic layer 13 overlap. In a plan view of the sheet substrate 1, each of the rectangular regions separated by grooves 11A and 11B corresponds to one base 10. Note that the lower surface of the sheet substrate 1 (the lower surface of the third ceramic layer 13) does not have a groove parallel to the short side along [B]-[C], but a dotted line is drawn in a plan view where it overlaps with the groove 11B formed on the upper surface of the first ceramic layer 11 to facilitate identification of the individual bases 10.

[0041] A first cavity 18 is formed in the base 10 with the upper surface of the second ceramic layer 12 as the bottom surface, and through the portion of the through hole 16 in the first ceramic layer 11. A second cavity 19 is formed in the base 10 with the lower surface of the second ceramic layer 12 as the bottom surface, and through the portion of the through hole 17 in the third ceramic layer 13. In this embodiment, a piezoelectric vibrator 101 is housed in the first cavity 18, and a thermistor 102 is housed in the second cavity 19 (see Figure 9).

[0042] As shown in Figure 4, a metal layer 21 is formed on the upper surface of the first ceramic layer 11, extending around the entire circumference of the through hole 16 for each base 10. The metal layer 21 is used when joining the lid 103, which constitutes the piezoelectric vibration device 100, to the upper surface of the base 10 (the upper surface of the first ceramic layer 11) that constitutes the piezoelectric vibration device 100.

[0043] In the first ceramic layer 11, a first through-hole electrode 22 is formed for each base 10, penetrating the first ceramic layer 11 and positioned to overlap with the metal layer 21 in a plan view. The metal layer 21 and the first through-hole electrode 22 are joined and electrically connected.

[0044] As shown in Figure 5, a pair of first electrode pads 25 and second electrode pads 26 are formed on the upper surface of the second ceramic layer 12 for each base 10. The pair of first electrode pads 25 and second electrode pads 26 are located on one short side of the rectangular base 10 in plan view, such that a portion of them is exposed in plan view through through holes 16 formed in the first ceramic layer 11. In this embodiment, piezoelectric vibrators 101 are mounted on the pair of first electrode pads 25 and second electrode pads 26.

[0045] On the upper surface of the second ceramic layer 12, first to fourth through-hole connection electrodes 27a to 30a are formed near the four corners for each base 10. The fourth through-hole connection electrode 30a and the second electrode pad 26 are connected and electrically linked. Also, on the upper surface of the second ceramic layer 12, an electrode pad wiring pattern 31 is formed for each base 10. The electrode pad wiring pattern 31 and the first electrode pad 25 are connected and electrically linked. The electrode pad wiring pattern 31 and the second through-hole connection electrode 28a are connected and electrically linked.

[0046] In the second ceramic layer 12, a first through-hole electrode 27b is formed in each base 10, penetrating the second ceramic layer 12 and overlapping with the first through-hole connecting electrode 27a in a plan view. The first through-hole connecting electrode 27a and the first through-hole electrode 27b are joined and electrically connected. In addition, in the second ceramic layer 12, a second through-hole electrode 28b is formed in each base 10, penetrating the second ceramic layer 12 in a plan view and overlapping with the second through-hole connecting electrode 28a. The second through-hole connecting electrode 28a and the second through-hole electrode 28b are joined and electrically connected. In addition, in the second ceramic layer 12, a third through-hole electrode 29b is formed in each base 10, penetrating the second ceramic layer 12 in a plan view and overlapping with the third through-hole connecting electrode 29a. The third through-hole connecting electrode 29a and the third through-hole electrode 29b are joined and electrically connected. Furthermore, in the second ceramic layer 12, a fourth through-hole electrode 30b is formed in each base 10, at a position overlapping with the fourth through-hole connecting electrode 30a, which penetrates the second ceramic layer 12 in a plan view. The fourth through-hole connecting electrode 30a and the fourth through-hole electrode 30b are joined and electrically connected.

[0047] On the upper surface of the second ceramic layer 12, a fifth through-hole connecting electrode 36 is formed for each base 10, in a position that overlaps with the first through-hole electrode 22 (see Figure 4) and the third through-hole connecting electrode 29a of the first ceramic layer 11 in a plan view. The first through-hole electrode 22 and the fifth through-hole connecting electrode 36 are joined and electrically connected. The third through-hole connecting electrode 29a and the fifth through-hole connecting electrode 36 are joined and electrically connected.

[0048] On the upper surface of the second ceramic layer 12, a support portion (cushion portion) 37 consisting of two layers is formed for each base 10 at a position corresponding to the free end of the piezoelectric vibrator 101 to be housed. The support portion (cushion portion) 37 is intended to prevent the piezoelectric vibrator 101 from contacting the upper surface of the second ceramic layer 12 when the housed piezoelectric vibrator 101 vibrates.

[0049] In Figure 5, hatches are shown in the parts of each electrode pad that do not overlap with the through-holes 16 of the first ceramic layer 11 in a plan view, while hatches are not shown in the parts that do overlap with the through-holes 16. Also, in Figure 5, grooves parallel to the long side along [A]-[B] and grooves parallel to the short side along [B]-[C] are not formed on the upper surface of the second ceramic layer 12, but dotted lines are placed at positions that overlap with grooves 11A and grooves 11B formed on the upper surface of the first ceramic layer 11 in a plan view in order to facilitate the identification of individual bases 10.

[0050] As shown in Figure 6, on the lower surface of the second ceramic layer 12, a pair of first electrode pads 41 and second electrode pads 42 are formed near the center of each base 10, so as to be exposed in plan view through through holes 17 formed in the third ceramic layer 13. In this embodiment, thermistors 102 are mounted on the pair of first electrode pads 41 and second electrode pads 42.

[0051] On the lower surface of the second ceramic layer 12, a first wiring pattern 43 extending from the first electrode pad 41 is formed for each base 10, as shown in Figure 6. The first wiring pattern 43 branches into two, with each branch extending to the long side [A]-[B] of the rectangular base 10 in plan view.

[0052] On the lower surface of the second ceramic layer 12, a second wiring pattern 44 is formed for each base 10, extending from the second electrode pad 42. The second wiring pattern 44 branches into two. One branch of the second wiring pattern 44 extends to the long side [C]-[D] of the rectangular base 10 in plan view. The other branch of the second wiring pattern 44 extends to the short side [B]-[C] of the rectangular base 10 in plan view.

[0053] A third wiring pattern 45 is formed on the lower surface of the second ceramic layer 12 for each base 10. The third wiring pattern 45 extends in a bent manner from the longer side [C]-[D] to the shorter side [D]-[A] of the rectangular base 10 in plan view.

[0054] One branched wiring pattern in the first wiring pattern 43 of base 10 is connected to one of the wiring patterns in the second wiring pattern 44 of the base 10 adjacent to base 10 on the [A]-[B] side (the base 10 above base 10 in Figure 6: referred to here as the "first adjacent base 10"). The other wiring pattern in the first wiring pattern 43 of base 10 is connected to one end of the third wiring pattern 45 of the first adjacent base 10.

[0055] One end of the second wiring pattern 44 of base 10 is connected to one end of the first wiring pattern 43 of the base 10 adjacent to base 10 on the [C]-[D] side (the base 10 below base 10 in Figure 6: referred to here as the "third adjacent base 10"). The other end of the second wiring pattern 44 of base 10 is connected to the other end of the third wiring pattern 45 of the base 10 adjacent to base 10 on the [B]-[C] side (the base 10 to the right of base 10 in Figure 6: referred to here as the "second adjacent base 10").

[0056] One end of the third wiring pattern 45 of base 10 is connected to the other end of the first wiring pattern 43 of the third adjacent base 10. The other end of the third wiring pattern 45 of base 10 is connected to the other end of the second wiring pattern 44 of the base 10 adjacent to base 10 on the [D]-[A] side (the base 10 to the left of base 10 in Figure 6: referred to here as the "fourth adjacent base 10").

[0057] The first wiring pattern 43 of base 10 and the second wiring pattern 44 and third wiring pattern 45 of the first adjacent base 10 form a wiring pattern that spans the boundary between base 10 and the first adjacent base 10. The second wiring pattern 44 of base 10 and the third wiring pattern 45 of the second adjacent base 10 form a wiring pattern that spans the boundary between base 10 and the second adjacent base 10. The second wiring pattern 44 and third wiring pattern 45 of base 10 and the first wiring pattern 43 of the third adjacent base 10 form a wiring pattern that spans the boundary between base 10 and the third adjacent base 10. The third wiring pattern 45 of base 10 and the second wiring pattern 44 of the fourth adjacent base 10 form a wiring pattern that spans the boundary between base 10 and the fourth adjacent base 10.

[0058] On the lower surface of the second ceramic layer 12, for each base 10, a first through-hole connection electrode 46 is formed at a position that overlaps with the first wiring pattern 43 and the first through-hole electrode 27b in a plan view. The first through-hole connection electrode 46 and the first wiring pattern 43 are electrically connected. The first through-hole connection electrode 46 and the first through-hole electrode 27b are electrically connected. On the lower surface of the second ceramic layer 12, for each base 10, a second through-hole connection electrode 47 is formed at a position that overlaps with the second through-hole electrode 28b in a plan view. The second through-hole connection electrode 47 and the second through-hole electrode 28b are electrically connected. On the lower surface of the second ceramic layer 12, for each base 10, a third through-hole connection electrode 48 is formed at a position that overlaps with the second wiring pattern 44 and the third through-hole electrode 29b in a plan view. The third through-hole connection electrode 48 and the second wiring pattern 44 are electrically connected. The third through-hole connection electrode 48 and the third through-hole electrode 29b are electrically connected. On the lower surface of the second ceramic layer 12, for each base 10, a fourth through-hole connection electrode 49 is formed in a position that overlaps with the third wiring pattern 45 and the fourth through-hole electrode 30b in a plan view. The fourth through-hole connection electrode 49 and the third wiring pattern 45 are electrically connected. The fourth through-hole connection electrode 49 and the fourth through-hole electrode 30b are electrically connected.

[0059] In Figure 6, hatches are shown in the parts of each electrode pad that do not overlap with the through-holes 17 of the third ceramic layer 13 in a plan view, while hatches are not shown in the parts that do overlap with the through-holes 17. Also, in Figure 6, grooves parallel to [A]-[B] and grooves parallel to [B]-[C] are not formed on the lower surface of the second ceramic layer 12, but dotted lines are placed at positions that overlap with grooves 11A and groove 11B formed on the upper surface of the first ceramic layer 11 in a plan view in order to facilitate the identification of individual bases 10.

[0060] As shown in Figure 7, on the upper surface of the third ceramic layer 13, for each base 10, a first through-hole connection electrode 51a is formed in a position that overlaps with the first through-hole connection electrode 46 formed on the lower surface of the second ceramic layer 12 in a plan view. The first through-hole connection electrode 51a and the first through-hole connection electrode 46 are electrically connected. On the upper surface of the third ceramic layer 13, for each base 10, a second through-hole connection electrode 52a is formed in a position that overlaps with the second through-hole connection electrode 47 formed on the lower surface of the second ceramic layer 12 in a plan view. The second through-hole connection electrode 52a and the second through-hole connection electrode 47 are electrically connected. On the upper surface of the third ceramic layer 13, for each base 10, a third through-hole connection electrode 53a is formed in a position that overlaps with the third through-hole connection electrode 48 formed on the lower surface of the second ceramic layer 12 in a plan view. The third through-hole connecting electrode 53a and the third through-hole connecting electrode 48 are electrically connected. On the upper surface of the third ceramic layer 13, a fourth through-hole connecting electrode 54a is formed for each base 10, in a position that overlaps with the fourth through-hole connecting electrode 49 formed on the lower surface of the second ceramic layer 12 in a plan view. The fourth through-hole connecting electrode 54a and the fourth through-hole connecting electrode 49 are electrically connected.

[0061] In the third ceramic layer 13, a first through-hole electrode 51b is formed in each base 10, penetrating the third ceramic layer 13 and positioned to overlap with the first through-hole connecting electrode 51a in a plan view. The first through-hole connecting electrode 51a and the first through-hole electrode 51b are electrically connected. In the third ceramic layer 13, a second through-hole electrode 52b is formed in each base 10, penetrating the third ceramic layer 13 and positioned to overlap with the second through-hole connecting electrode 52a in a plan view. The second through-hole connecting electrode 52a and the second through-hole electrode 52b are electrically connected. In the third ceramic layer 13, a third through-hole electrode 53b is formed in each base 10, penetrating the third ceramic layer 13 and positioned to overlap with the third through-hole connecting electrode 53a in a plan view. The third through-hole connecting electrode 53a and the third through-hole electrode 53b are electrically connected. In the third ceramic layer 13, a fourth through-hole electrode 54b is formed for each base 10, penetrating the third ceramic layer 13, at a position that overlaps with the fourth through-hole connecting electrode 54a in a plan view. The fourth through-hole connecting electrode 54a and the fourth through-hole electrode 54b are electrically connected.

[0062] In Figure 7, the lower surface of the third ceramic layer 13 does not have grooves parallel to [A]-[B] and grooves parallel to [B]-[C]. However, to facilitate the identification of individual bases 10, dotted lines are drawn at positions that overlap with grooves 11A and 11B formed on the upper surface of the first ceramic layer 11 in a plan view.

[0063] As shown in Figure 8, on the lower surface of the third ceramic layer 13, a pair of first external connection terminals 61 and second external connection terminals 62 are formed on each base 10, spaced apart from the outer edge of the base 10 in a plan view. The pair of first external connection terminals 61 and second external connection terminals 62 are arranged diagonally on the rectangular base 10. The first external connection terminal 61 is formed spaced apart from the long side on the [A]-[B] side and the short side on the [B]-[C] side of the rectangular base 10 in a plan view. The second external connection terminal 62 is formed spaced apart from the long side on the [C]-[D] side and the short side on the [D]-[A] side of the rectangular base 10 in a plan view. The first external connection terminal 61 and the second through-hole electrode 52b formed on the third ceramic layer 13 are joined and electrically connected. The second external connection terminal 62 and the fourth through-hole electrode 54b formed on the third ceramic layer 13 are joined and electrically connected.

[0064] In this embodiment, the pair of first external connection terminals 61 and second external connection terminals 62 are a pair of external connection terminals for piezoelectric vibrators that electrically connect the piezoelectric vibrator 101 mounted on a pair of first electrode pads 25 and second electrode pads 26 formed on the upper surface of the second ceramic layer 12 to the outside. The first external connection terminal 61, which is an external connection terminal for piezoelectric vibrators, is connected to the first electrode pad 25 via a second through-hole electrode 52b formed in the third ceramic layer 13, a second through-hole connection electrode 52a formed on the upper surface of the third ceramic layer 13, a second through-hole connection electrode 47 formed on the lower surface of the second ceramic layer 12, a second through-hole electrode 28b formed in the second ceramic layer 12, a second through-hole connection electrode 28a formed on the upper surface of the second ceramic layer 12, and an electrode pad wiring pattern 31 formed on the upper surface of the second ceramic layer 12. The other external connection terminal for the piezoelectric vibrator, the second external connection terminal 62, is connected to the second electrode pad 26 via a fourth through-hole electrode 54b formed in the third ceramic layer 13, a fourth through-hole connection electrode 54a formed on the upper surface of the third ceramic layer 13, a fourth through-hole connection electrode 49 formed on the lower surface of the second ceramic layer 12, a fourth through-hole electrode 30b formed in the second ceramic layer 12, and a fourth through-hole connection electrode 30a formed on the upper surface of the second ceramic layer 12.

[0065] On the lower surface of the third ceramic layer 13, for each base 10, a pair of external connection terminals, excluding the pair of first external connection terminals 61 and second external connection terminals 62 which are external connection terminals for a pair of piezoelectric vibrators, are formed spaced apart from the outer edge of the base 10 in a plan view. The pair of third external connection terminals 63 and fourth external connection terminals 64 are located diagonally opposite each other in the rectangular base 10. The first external connection terminal, the third external connection terminal 63, is formed spaced apart from the short side on the [D]-[A] side and the long side on the [A]-[B] side in a plan view of the rectangular base 10. The second external connection terminal, the fourth external connection terminal 64, is formed spaced apart from the short side on the [B]-[C] side and the long side on the [C]-[D] side in a plan view of the rectangular base 10. The third external connection terminal 63 and the first through-hole electrode 51b formed in the third ceramic layer 13 are electrically connected. The fourth external connection terminal 64 and the third through-hole electrode 53b formed in the third ceramic layer 13 are electrically connected. In the third ceramic layer 13 where the external connection terminals are formed, the second ceramic layer 12 and the first ceramic layer 11 are laminated on the surface opposite to the outer bottom surface where the external connection terminals are located.

[0066] In this embodiment, a pair of third external connection terminals 63 and fourth external connection terminals 64 are mounted on a pair of first electrode pads 41 and second electrode pads 42 formed on the lower surface of the second ceramic layer 12. In this embodiment, they are for electrically connecting the thermistor 102 to the outside. The third external connection terminal 63 is connected to the first electrode pad 41 via a first through-hole electrode 51b formed in the third ceramic layer 13, a first through-hole connection electrode 51a formed on the upper surface of the third ceramic layer 13, a first through-hole connection electrode 46 formed on the lower surface of the second ceramic layer 12, and a first wiring pattern 43 formed on the lower surface of the second ceramic layer 12. The fourth external connection terminal 64 is connected to the second electrode pad 42 via a third through-hole electrode 53b formed in the third ceramic layer 13, a third through-hole connection electrode 53a formed on the upper surface of the third ceramic layer 13, a third through-hole connection electrode 48 formed on the lower surface of the second ceramic layer 12, and a second wiring pattern 44 formed on the lower surface of the second ceramic layer 12.

[0067] On the lower surface of the third ceramic layer 13, a first connection portion 65 extending from the first external connection terminal 61 is formed for each base 10. The first connection portion 65 extends to the short side on the [B]-[C] side in the base 10 that is rectangular in plan view. When comparing the length D1 of the first connection portion 65 in the direction from [B] to [C] with the length D2 of the first external connection terminal 61 in the direction from [B] to [C], D1 < D2. The first connection portion 65 extends from the first external connection terminal 61 so as to be formed at a location other than near the corner of the base 10 (the corner on the [B] side of the base 10).

[0068] On the lower surface of the third ceramic layer 13, a second connection portion 66 extending from the third external connection terminal 63 is formed for each base 10. The second connection portion 66 extends to the short side on the [D]-[A] side in the base 10 having a rectangular shape in plan view. When the length D1 of the second connection portion 66 in the direction from [B] to [C] is compared with the length D2 of the third external connection terminal 63 in the direction from [B] to [C], D1 < D2. The second connection portion 66 extends from the third external connection terminal 63 so as to be formed at a location other than near the corner of the base 10 (the corner on the [A] side of the base 10).

[0069] The first connection portion 65 of the base 10 is connected to the second connection portion 66 of the base 10 (the base 10 on the right side with respect to the base 10 in FIG. 8: here, it is described as the "second adjacent base 10"), which is the first base adjacent to the base 10 on the [B]-[C] side among the plurality of bases 10 adjacent to the base 10. The first connection portion 65 of the base 10 and the second connection portion 66 of the second adjacent base 10 straddle the boundary between the base 10 and the second adjacent base 10, and form a connection portion that electrically connects the first external connection terminal 61, which is one of the external connection terminals for the piezoelectric vibration piece of the base 10, and the third external connection terminal 63, which is the first external connection terminal of the first base 10, that is, the second adjacent base 10. That is, the first external connection terminal 61 of the base 10 and the third external connection terminal 63 of the second adjacent base 10 are electrically connected by being connected through the first connection portion 65 and the second connection portion 66 on the lower surface of the third ceramic layer 13 (the outer bottom surface of the sheet substrate 1).

[0070] The second connection part 66 of the base 10 is connected to the first connection part 65 of the base 10 (the base 10 on the left side of the base 10 in FIG. 8: hereinafter referred to as the "fourth adjacent base 10"), which is a predetermined base adjacent to the [D]-[A] side of the base 10. The second connection part 66 of the base 10 and the first connection part 65 of the fourth adjacent base 10 straddle the boundary between the base 10 and the fourth adjacent base 10, and form a connection part that electrically connects the third external connection terminal 63, which is the first external connection terminal of the base 10, and the first external connection terminal 61, which is one of the external connection terminals for the piezoelectric vibration piece of the fourth adjacent base 10. That is, the third external connection terminal 63 of the base 10 and the first external connection terminal 61 of the fourth adjacent base 10 are electrically connected by being connected through the connection part on the lower surface of the third ceramic layer 13 (the outer bottom surface of the sheet substrate 1).

[0071] Since D1 < D2 for the first external connection terminal 61, compared with a configuration in which it is connected to the third external connection terminal 63 of the adjacent base 10 without being separated inward with respect to the outer peripheral edge of the outer bottom surface of the base 10, it is less susceptible to the influence of heat caused by the irradiation of the energy beam described later. Specifically, as shown in FIG. 8, the first external connection terminal 61 is formed so as to be separated inward with respect to the outer peripheral edge of the outer bottom surface of the base 10, and the space between it and the third external connection terminal 63 of the adjacent base 10 is connected by the first connection part 65 and the second connection part 66 having a length of D1 that is smaller than D2, so that the area to be cut by laser irradiation can be minimized. That is, since the cut area by the energy beam becomes smaller, it is possible to suppress the diffusion of nickel in the nickel plating layer into the upper gold plating layer among the first external connection terminal 61 made of a multilayer metal film and the third external connection terminal 63 of the adjacent base 10 due to the heat caused by the irradiation of the energy beam. As a result, it is possible to prevent a decrease in the wettability of the solder of the first external connection terminal 61 and the third external connection terminal 63 of the adjacent base 10, so that the connection reliability with the external substrate is improved.

[0072] Furthermore, in this embodiment, the connection portions (first connection portion 65, second connection portion 66) are formed in a position that does not include the corner furthest from the center of the outer bottom surface of the base 10 among the multiple corners of the external connection terminals (first external connection terminal 61, third external connection terminal 63) in a plan view. Generally, in a configuration in which an external connection terminal having multiple corners is formed near the outer edge of the outer bottom surface of the base 10, it is known that the corner furthest from the center of the outer bottom surface of the base 10 in a plan view is the starting point for solder deterioration over time. In this embodiment, since the connection portion is not connected to the corner furthest from the center of the outer bottom surface of the base 10 in a plan view, the furthest corner is not heated by the energy beam. This prevents a decrease in solder wettability due to the diffusion of nickel from the nickel plating layer into the gold plating layer above it.

[0073] The second external connection terminal 62, which is an external connection terminal for the piezoelectric vibrator on the other side of base 10, is electrically connected to the fourth external connection terminal 64 of the second external connection terminal of the second base 10 (the base 10 to the left of the base 10 in Figure 8), which is a second external connection terminal of the second base 10 adjacent to the base 10 on the [D]-[A] side of the base 10, and the third external connection terminal 63 of the base 10 adjacent to the base 10 on the [C]-[D] side of the base 10 (the base 10 below the base 10 in Figure 8), by wiring formed inside the sheet substrate 1 (through-hole electrodes (51b, 53b, 54b) formed on the lower surface of the third ceramic layer 13, through-hole connection electrodes (51a, 53a, 54a) formed on the upper surface of the third ceramic layer 13, through-hole connection electrodes (46, 48, 49) formed on the lower surface of the second ceramic layer 12, and wiring patterns (43, 44, 45) formed on the lower surface of the second ceramic layer 12), among the multiple bases 10, by wiring formed inside the sheet substrate 1 (through-hole electrodes (51b, 53b, 54b) formed on the lower surface of the third ceramic layer 13, through-hole connection electrodes (51a, 53a, 54a) formed on the upper surface of the third ceramic layer 13, through-hole connection electrodes (46, 48, 49) formed on the lower surface of the second ceramic layer 12, wiring patterns (43, 44, 45) formed on the lower surface of the second ceramic layer 12, etc.).

[0074] The third external connection terminal 63, which is the first external connection terminal of base 10, is electrically connected to the second external connection terminal 62 of a base 10 adjacent to the base 10 on the [A]-[B] side (the base 10 above the base 10 in Figure 8) by wiring formed inside the sheet substrate 1 (through-hole electrodes (51b, 54b) formed in the third ceramic layer 13, through-hole connection electrodes (51a, 54a) formed on the upper surface of the third ceramic layer 13, first through-hole connection electrodes (46, 49) formed on the lower surface of the second ceramic layer 12, wiring patterns (43, 45) formed on the lower surface of the second ceramic layer 12, etc.) among the multiple bases 10.

[0075] The fourth external connection terminal 64, which is the second external connection terminal of base 10, is electrically connected to the second external connection terminal 62, which is the other external connection terminal for the piezoelectric vibrator of base 10, and to the second external connection terminal 62 of the base 10 adjacent to the base 10 on the [B]-[C] side of the base 10 (the base 10 to the right of the base 10 in Figure 8), etc., by wiring formed inside the sheet substrate 1 (through-hole electrodes (53b, 54b) formed in the third ceramic layer 13, through-hole connection electrodes (53a, 54a) formed on the upper surface of the third ceramic layer 13, through-hole connection electrodes (48, 49) formed on the lower surface of the second ceramic layer 12, wiring patterns (43, 44, 45) formed on the lower surface of the second ceramic layer 12, etc.) formed inside the sheet substrate 1, etc.

[0076] Furthermore, the second external connection terminal 62 of base 10 is not electrically connected to any of the first to fourth external connection terminals 61 to 64 of any base 10 adjacent to base 10 at the lower surface of the third ceramic layer 13 (the outer bottom surface of the sheet substrate 1). In addition, there is no connection part provided that electrically connects the second external connection terminal 62 of base 10 to any of the first to fourth external connection terminals 61 to 64 of any base 10 adjacent to base 10 by connecting them at the lower surface of the third ceramic layer 13 (the outer bottom surface of the sheet substrate 1).

[0077] Note that in Figure 8, no grooves parallel to "B" and "C" are formed on the lower surface of the third ceramic layer 13, but dotted lines are drawn in a position that overlaps with the groove 11B formed on the upper surface of the first ceramic layer 11 in a plan view, in order to facilitate the identification of individual bases 10.

[0078] The external connection terminals (61-64), connection parts (65-66), through-hole electrodes (51b-54b), through-hole connection electrodes (51a-54a), electrode pads (41-42), wiring patterns (43-45), through-hole connection electrodes (46-49), electrode pads (25-26), through-hole connection electrodes (27a-30a), wiring patterns (31), through-hole electrodes (27b-30b), through-hole connection electrodes (36), through-hole electrodes (22), and metal layer (21) are each formed by laminating a molybdenum (Mo) metallized layer, a nickel (Ni) plated layer, and a gold (Au) plated layer in that order from the forming surface. Note that tungsten (W), for example, may be used as the metallized layer instead of molybdenum.

[0079] Next, using the sheet substrate 1 described with reference to Figures 1 to 8, the configuration of the piezoelectric vibration device 100 manufactured by the method for manufacturing a piezoelectric vibration device according to this embodiment will be described with reference to Figure 9. Figure 9 is a schematic cross-sectional view of the piezoelectric vibration device 100 according to this embodiment.

[0080] The piezoelectric vibration device 100 comprises a base 10, a piezoelectric vibrator 101 housed in a first cavity 18 of the base 10, a thermistor 102 housed in a second cavity 19 of the base 10, and a lid 103 for hermetically sealing the piezoelectric vibrator 101 housed in the first cavity 18 of the base 10. The base 10 has an H-shaped structure in cross-section.

[0081] The piezoelectric vibrator 101 housed in the first cavity 18 has a pair of electrodes that are mechanically and electrically connected to a pair of electrode pads (first electrode pad 25, second electrode pad 26) on the base 10 using conductive joints 104 such as metal bumps and conductive adhesive.

[0082] The thermistor 102 housed in the second cavity 19 has its pair of electrodes mechanically and electrically connected to a pair of electrode pads (first electrode pad 41, second electrode pad 42) on the base 10 using solder 105.

[0083] Next, a method for manufacturing a piezoelectric vibration device according to this embodiment will be described, which involves manufacturing a piezoelectric vibration device 100 using the sheet substrate 1 described with reference to Figures 1 to 8. The method for manufacturing a piezoelectric vibration device includes a cutting step.

[0084] First, a molybdenum metallized layer is formed on each of the first ceramic layer 11, the second ceramic layer 12, and the third ceramic layer 13. Then, the first ceramic layer 11, the second ceramic layer 12, and the third ceramic layer 13 are stacked. Next, grooves 11A and 11B are formed on the upper surface of the first ceramic layer 11 using a metal snap, laser snap, or the like (see Figure 1), and grooves 13B are formed on the lower surface of the third ceramic layer 13 using a metal snap, laser snap, or the like. Subsequently, nickel plating layers are stacked on the molybdenum metallized layers by firing the first to third ceramic layers 11 to 13 and electroplating, and then a gold plating layer is stacked on the nickel plating layers using electroplating. In this way, the sheet substrate 1 is manufactured. However, the manufacturing method of the sheet substrate 1 is not particularly limited, and any method of manufacturing a sheet substrate that can realize the structure of the sheet substrate 1 described with reference to Figures 1 to 8 is acceptable.

[0085] Next, an energy beam (laser beam, electron beam, etc.) is irradiated onto the lower surface of the third ceramic layer 13 constituting the manufactured sheet substrate 1, along the boundary between adjacent bases 10 (along the dotted line drawn on the lower surface of the third ceramic layer 13 in Figure 2), based on a predetermined shape of the base 10. This forms a groove along the boundary between adjacent bases 10 on the lower surface of the third ceramic 13, and physically severs the connection between the adjacent first external connection terminal 61 and the third external connection terminal 63 (the connection formed from the adjacent first connection part 65 and the second connection part 66), thereby seversing the electrical connection between the adjacent first external connection terminal 61 and the third external connection terminal 63 and electrically separating the first external connection terminal 61 from the third external connection terminal 63 (separation process). The groove formed in the third ceramic layer 13 by irradiation with the energy beam is formed in a position that overlaps with the groove 11B of the first ceramic layer 11 in a plan view.

[0086] Next, for each base 10, the piezoelectric vibrator 101 is housed in the first cavity 18 of the base 10. At this time, the characteristics such as frequency are measured in the base 10 with the piezoelectric vibrator 101 housed in the first cavity 18. Subsequently, for each base 10, the opening on the upper surface of the first ceramic layer 11 constituting the sheet substrate 1 is closed with a lid 103, and the thermistor 102 is housed in the second cavity 19 of the base 10. Subsequently, the piezoelectric vibration device 100, comprising the base 10, piezoelectric vibrator 101, thermistor 102, and lid 103, is separated into individual pieces using grooves 11A and 11B formed on the upper surface of the first ceramic layer 11, groove 13B formed on the lower surface of the third ceramic layer 13, and grooves formed by irradiation with an energy beam.

[0087] According to the embodiment described above, in the cutting process, in adjacent bases 10, the connection portion (composed of a first connection portion 65 extending from the first external connection terminal 61 and a second connection portion 66 extending from the third external connection terminal 63) that electrically connects the first external connection terminal 61, which is an external connection terminal for one adjacent piezoelectric vibrator, and the third external connection terminal 63, which is a first external connection terminal, is cut with an energy beam, thereby cutting the electrical connection between the first external connection terminal 61 and the third external connection terminal 63, and the first external connection terminal 61 can be made electrically independent. As a result, even in a sheet substrate 1 in which multiple (nine in this embodiment) bases 10 are integrally connected, the characteristics of the piezoelectric vibration device 100 can be measured while suppressing the influence of other bases 10 by bringing a measurement probe into contact with each of the first external connection terminals 61 and the second external connection terminals 62 that are electrically connected to the piezoelectric vibrator 101 in each base 10.

[0088] Furthermore, since the second external connection terminal 62 of the base 10 is not electrically connected to the first external connection terminal 61 to the fourth external connection terminal 64 of the other base 10 on the lower surface of the third ceramic layer 13 (the outer bottom surface of the sheet substrate 1), the area irradiated with the energy beam during the cutting process can be limited to a portion of the dotted line drawn in Figure 2, including the connection portion formed by the adjacent first connection portion 65 and second connection portion 66.

[0089] Furthermore, the first external connection terminal 61 to the fourth external connection terminal 64 typically have a configuration in which a plating layer is laminated on a metallized layer that serves as the base metal layer. If each of the first external connection terminal 61 to the fourth external connection terminal 64 is not spaced inward relative to the outer edge of the outer bottom surface of the base 10 in a plan view, then when an energy beam is irradiated along the boundary between adjacent bases 10 to cut the boundary between the connected external connection terminals (61-64), the plating layer at that boundary portion of the external connection terminals (61-64) will be scraped off. When the plating layer is scraped off, the base metal layer that was covered by the plating layer is exposed to the outside, which may be undesirable in terms of environmental resistance depending on the type of base metal layer. For example, if the base metal layer is a molybdenum metallized layer, it is susceptible to corrosion by hot water. Since each of the first external connection terminals 61 to 64 is formed spaced inward from the outer edge of the bottom surface of the base 10 in a plan view, interference between the energy beam and the first external connection terminal 61 to the fourth external connection terminal 64 can be eliminated, and the aforementioned problem can be prevented.

[0090] Furthermore, the electroplating method allows for the deposition of numerous films on the outer bottom surface of the sheet substrate 1, from the first external connection terminal 61 to the fourth external connection terminal 64, in a single process.

[0091] Furthermore, by irradiating the energy beam along the shape of the base 10, the adjacent first external connection terminal 61 and third external connection terminal 63 of adjacent bases 10 can be reliably separated, thereby severing the electrical connection between the first external connection terminal 61 and the third external connection terminal 63, and simultaneously thinning the boundary portion of the adjacent base 10. Alternatively, this portion may be cut.

[0092] Compared to cutting tools like blade dicing, energy beams offer superior production efficiency because they eliminate the need for parts replacement associated with blade wear and tear. Furthermore, they allow for smaller cutting depths compared to blade dicing. As a result, the number of piezoelectric vibration devices obtainable from a single sheet substrate increases. Additionally, using an energy beam cutting device enables reliable cutting even in minute areas.

[0093] Furthermore, since the characteristics of each individual piezoelectric vibration device 100 can be measured when multiple piezoelectric vibration devices 100 are connected in a series, it is possible to obtain a piezoelectric vibration device 100 with excellent characteristics.

[0094] [Modified example of Embodiment 1] Next, with reference to Figures 10 to 12, a method for manufacturing a piezoelectric vibration device according to a modified embodiment of the present invention, a piezoelectric vibration device manufactured by the manufacturing method, and a sheet substrate used in the manufacturing method will be described with reference to the drawings. Figure 10 is a schematic plan view of the upper side of the second ceramic layer 12A constituting the sheet substrate 1A in a modified embodiment of the present invention. Figure 11 is a schematic plan view (perspective view) of the lower side of the second ceramic layer 12A constituting the sheet substrate 1A. Figure 12 is a schematic plan view (perspective view) of the lower side of the third ceramic layer 13A constituting the sheet substrate 1A. The sheet substrate 1A differs in that both the first external connection terminal 61 and the second external connection terminal 62, which are a pair of external connection terminals for piezoelectric vibration pieces, are connected to the external connection terminals. Note that the same letters [A], [B], [C], and [D] in Figures 10 to 12 are included to facilitate understanding of the corresponding positions. In Figures 10 to 12, the multiple bases 10 formed in a matrix on the sheet substrate 1A have the same structure, and the numbering is omitted in some parts in Figures 10 to 12.

[0095] A sheet substrate 1A, which is a modified embodiment of the present invention, is a ceramic laminate consisting of three layers, including a first ceramic layer 11, a second ceramic layer 12A, and a third ceramic layer 13A, which are laminated in the order of the third ceramic layer 13A, the second ceramic layer 12A, and the first ceramic layer 11. In a plan view, rectangular regions of the sheet substrate 1A, separated by grooves 11A and 11B (see Figure 1), each constitute one base 10. The first ceramic layer 11, the second ceramic layer 12A, and the third ceramic layer 13A are arranged in a matrix consisting of 3 rows and 3 columns of base 10, but the matrix may have other configurations.

[0096] The first ceramic layer 11 has a rectangular outer periphery in plan view, and rectangular through-holes 16 are formed in a matrix in plan view (see Figure 4). The second ceramic layer 12A and the third ceramic layer 13A are rectangular flat plates in plan view. Therefore, each base 10 of the sheet substrate has the upper surface of the second ceramic layer 12A as its bottom surface, and a first cavity 18 is formed surrounded by the first ceramic layer 11 having through-holes 16. In this embodiment, a piezoelectric vibrator 101 is housed in the first cavity 18 (see Figure 13).

[0097] As shown in Figure 10, a pair of first electrode pads 25 and second electrode pads 26 are located on the upper surface of the second ceramic layer 12A for each base 10. The pair of first electrode pads 25 and second electrode pads 26 are formed side by side in the short-side direction on one short side of the rectangular base 10 in plan view. Also located on the upper surface of the second ceramic layer 12A is an electrode pad wiring pattern 31 that extends in the long-side direction from the first electrode pad 25. The electrode pad wiring pattern 31 and the first electrode pad 25 are electrically connected.

[0098] Furthermore, on the upper surface of the second ceramic layer 12A, second to fourth through-hole connection electrodes 28a to 30a are formed near the corners for each base 10. The electrode pad wiring pattern 31, the second through-hole connection electrode 28a, and the second through-hole electrode 28b that penetrates the second ceramic layer 12A are connected and electrically linked. On the upper surface of the second ceramic layer 12A, the third through-hole electrode 29b and the third through-hole connection electrode 29a that penetrate the second ceramic layer 12A are located in positions where they are not electrically connected to the first electrode pad 25, the second electrode pad 26, and the electrode pad wiring pattern 31. The second electrode pad 26, the fourth through-hole connection electrode 30a, and the fourth through-hole electrode 30b that penetrates the second ceramic layer 12A are connected and electrically linked.

[0099] As shown in Figure 11, the lower surface of the second ceramic layer 12A has a first wiring pattern 43A that extends from the long side on the [A]-[B] side toward the short side on the [A]-[D] side in a plan view, for each base 10. The lower surface of the second ceramic layer 12A also has a second wiring pattern 44A that extends from the long side on the [D]-[C] side toward the short side on the [B]-[C] side in a plan view, for each base 10.

[0100] The [A]-[D] end of the first wiring pattern 43A is connected to the [B]-[C] end of the second wiring pattern 44A of the base 10 adjacent to the [A]-[D] side of the base 10 (the base 10 to the left of the base 10 in Figure 11: referred to here as the "fourth adjacent base 10"). Also, the [A]-[B] end of the first wiring pattern 43A is connected to the [D]-[C] end of the second wiring pattern 44A of the base 10 adjacent to the [A]-[B] side of the base 10 (the base 10 above the base 10 in Figure 11: referred to here as the "first adjacent base 10").

[0101] The [D]-[C] end of the second wiring pattern 44A is connected to the [A]-[B] end of the first wiring pattern 43A of the base 10 adjacent to the [C]-[D] side of the base 10 (the base 10 below the base 10 in Figure 11: referred to here as the "third adjacent base 10"). Also, the [B]-[C] end of the second wiring pattern 44A is connected to the [A]-[D] end of the first wiring pattern 43A of the base 10 adjacent to the [B]-[C] side of the base 10 (the base 10 to the right of the base 10 in Figure 11: referred to here as the "second adjacent base 10").

[0102] The first wiring pattern 43A of base 10 and the second wiring pattern 44A of the first adjacent base 10 form a wiring pattern that spans the boundary between base 10 and the first adjacent base 10. First wiring pattern 43A The second wiring pattern 44A of the fourth adjacent base 10 and the second wiring pattern 43A of the second adjacent base 10 form a wiring pattern that spans the boundary between base 10 and the fourth adjacent base 10. The second wiring pattern 44A of base 10 and the first wiring pattern 43A of the second adjacent base 10 form a wiring pattern that spans the boundary between base 10 and the second adjacent base 10. The second wiring pattern 44A of base 10 and the first wiring pattern 43A of the third adjacent base 10 form a wiring pattern that spans the boundary between base 10 and the third adjacent base 10.

[0103] On the underside of the second ceramic layer 12A, a first through-hole connection electrode 46 is formed for each base 10, in a position that overlaps with the first wiring pattern 43A in a plan view. The first through-hole connection electrode 46 and the first wiring pattern 43A are electrically connected. On the underside of the second ceramic layer 12, a second through-hole connection electrode 47 is formed for each base 10, in a position that overlaps with the second through-hole electrode 28b in a plan view. The second through-hole connection electrode 47 and the second through-hole electrode 28b are electrically connected. On the underside of the second ceramic layer 12, a third through-hole connection electrode 48 is formed for each base 10, in a position that overlaps with the second wiring pattern 44A in a plan view and also overlaps with the third through-hole electrode 29b in a plan view. Second wiring pattern 44A They are electrically connected. The third through-hole connection electrode 48 and the third through-hole electrode 29b are electrically connected. On the lower surface of the second ceramic layer 12, for each base 10, a fourth through-hole connection electrode 49 is formed in a position that overlaps with the fourth through-hole electrode 30b in a plan view. The fourth through-hole connection electrode 49 and the fourth through-hole electrode 30b are electrically connected.

[0104] On the upper surface of the third ceramic layer 13A, each base 10 has a first through-hole connection electrode 51a and a first through-hole electrode 51b, a second through-hole connection electrode 52a and a second through-hole electrode 52b, a third through-hole connection electrode 53a and a third through-hole electrode 53b, and a fourth through-hole connection electrode 54a and a fourth through-hole electrode 54b (see Figure 7). The first through-hole connection electrode 51a and the first through-hole connection electrode 46 are electrically connected. The second through-hole connection electrode 52a and the second through-hole connection electrode 47 are electrically connected. The third through-hole connection electrode 53a and the third through-hole connection electrode 48 are electrically connected. The fourth through-hole connection electrode 54a and the fourth through-hole connection electrode 49 are electrically connected.

[0105] As shown in Figure 12, on the lower surface of the third ceramic layer 13A, a pair of first external connection terminals 61 and second external connection terminals 62A are located diagonally opposite each other in a plan view of each base 10. The first external connection terminal 61 is electrically connected to the second through-hole electrode 52b (see Figure 7) formed on the upper surface of the third ceramic layer 13A. The second external connection terminal 62A is electrically connected to the fourth through-hole electrode 54b (see Figure 7) formed on the upper surface of the third ceramic layer 13A.

[0106] Furthermore, on the lower surface of the third ceramic layer 13A, a third external connection terminal 63 and a fourth external connection terminal 64A are located diagonally opposite each other in a plan view of each base 10. The third external connection terminal 63 is electrically connected to the first through-hole electrode 51b (see Figure 7) formed on the upper surface of the third ceramic layer 13A. The fourth external connection terminal 64A is electrically connected to the third through-hole electrode 53b (see Figure 7) formed on the upper surface of the third ceramic layer 13A.

[0107] In this embodiment, the pair of first external connection terminals 61 and second external connection terminals 62A are a pair of external connection terminals for piezoelectric vibrators that electrically connect to the outside the piezoelectric vibrator 101 (see Figure 13) mounted on a pair of first electrode pads 25 and second electrode pads 26 (see Figure 10) formed on the upper surface of the second ceramic layer 12A. The first external connection terminal 61, which is an external connection terminal for a piezoelectric vibrator, is connected to the first electrode pad 25 via a second through-hole electrode 52b formed on the upper surface of the third ceramic layer 13A, a second through-hole connection electrode 52a formed on the upper surface of the third ceramic layer 13A, a second through-hole connection electrode 47 (see Figure 11) formed on the lower surface of the second ceramic layer 12A, a second through-hole electrode 28b (see Figure 10) formed on the upper surface of the second ceramic layer 12A, and an electrode pad wiring pattern 31 formed on the upper surface of the second ceramic layer 12A. The other external connection terminal for the piezoelectric vibrator, the second external connection terminal 62A, is connected to the second electrode pad 26 via a fourth through-hole electrode 54b formed on the upper surface of the third ceramic layer 13A, a fourth through-hole connection electrode 54a formed on the upper surface of the third ceramic layer 13A (see Figure 7), a fourth through-hole connection electrode 49 formed on the lower surface of the second ceramic layer 12A (see Figure 11), a fourth through-hole electrode 30b formed on the upper surface of the second ceramic layer 12A, and a fourth through-hole connection electrode 30a formed on the upper surface of the second ceramic layer 12A (see Figure 10).

[0108] On the lower surface of the third ceramic layer 13A, for each base 10, a pair of external connection terminals, excluding the pair of first external connection terminals 61 and second external connection terminals 62A which are external connection terminals for a pair of piezoelectric vibrators, are formed, spaced apart from the outer edge of the base 10 in a plan view. The pair of third external connection terminals 63 and fourth external connection terminals 64A are arranged in a diagonal positional relationship on the rectangular base 10. The third external connection terminal 63 and the first through-hole electrode 51b formed in the third ceramic layer 13A are electrically connected. The fourth external connection terminal 64A and the third through-hole electrode 53b formed on the upper surface of the third ceramic layer 13A are electrically connected.

[0109] The third external connection terminal 63 is connected to the first wiring pattern 43A formed on the lower surface of the second ceramic layer 12 via the first through-hole electrode 51b formed on the upper surface of the third ceramic layer 13A and the first through-hole connection electrode 51a formed on the upper surface of the third ceramic layer 13A. The fourth external connection terminal 64A is connected to the third through-hole electrode 53b formed on the upper surface of the third ceramic layer 13A, the third through-hole connection electrode 53a formed on the upper surface of the third ceramic layer 13A, the third through-hole connection electrode 48 formed on the lower surface of the second ceramic layer 12A, the second wiring pattern 44A formed on the lower surface of the second ceramic layer 12A, and the first through-hole electrode 22 that penetrates the first ceramic layer 11.

[0110] On the lower surface of the third ceramic layer 13A, a first connection portion 65 (one connection portion) is formed for each base 10, extending from the first external connection terminal 61, and the first connection portion 65 extends to the short side on the [B]-[C] side of the base 10, which is rectangular in plan view.

[0111] On the lower surface of the third ceramic layer 13A, a second connection portion 66 is formed for each base 10, extending from the third external connection terminal 63, and the second connection portion 66 extends to the short side on the [D]-[A] side of the base 10, which is rectangular in plan view.

[0112] The first connection part 65 in base 10 is electrically connected to the second connection part 66 of the first base 10 (the base 10 on the right side of the base 10 in FIG. 12: hereinafter referred to as the "second adjacent base 10") adjacent to the base 10 on the [B]-[C] side among a plurality of bases 10 adjacent to the base 10. The second connection part 66 of the base 10 is electrically connected to the first connection part 65 of the base 10 (the base 10 on the left side of the base 10 in FIG. 12: hereinafter referred to as the "fourth adjacent base 10") which is a predetermined base adjacent to the [D]-[A] side of the base 10.

[0113] On the lower surface of the third ceramic layer 13A, a third connection part 67 (the other connection part) extending from the second external connection terminal 62A is formed for each base 10, and the third connection part 67 extends to the short side on the [A]-[D] side in the base 10 having a rectangular shape in plan view. When comparing the length D1 of the third connection part 67 in the direction from [C] to [D] with the length D2 of the second external connection terminal 62A in the direction from [C] to [D], D1 < D2. The third connection part 67 extends from the second external connection terminal 62A so as to be formed at a location other than near the corner of the base 10 (the corner on the [D] side of the base 10).

[0114] On the lower surface of the third ceramic layer 13A, a fourth connection part 68 extending from the fourth external connection terminal 64A is formed for each base 10, and the fourth connection part 68 extends to the short side on the [B]-[C] side in the base 10 having a rectangular shape in plan view. When comparing the length D1 of the fourth connection part 68 in the direction from [D] to [C] with the length D2 of the fourth external connection terminal 64A in the direction from [D] to [C], D1 < D2. The fourth connection part 68 extends from the fourth external connection terminal 64A so as to be formed at a location other than near the corner of the base 10 (the corner on the [C] side of the base 10).

[0115] The third connection portion 67 of base 10 is connected to the fourth connection portion 68 of the second base 10 (the base 10 to the left of base 10 in Figure 12; here referred to as the "fourth adjacent base 10"), which is adjacent to base 10 on the [A]-[D] side among a plurality of bases 10 adjacent to base 10. The third connection portion 67 of base 10 and the fourth connection portion 68 of the fourth adjacent base 10 straddle the boundary between base 10 and the fourth adjacent base 10 and form the other connection portion that electrically connects the second external connection terminal 62A, which is the external connection terminal for the piezoelectric vibrator on the other side of base 10, and the fourth external connection terminal 64A, which is the second external connection terminal of the fourth adjacent base 10, which is the second base 10. In other words, the second external connection terminal 62A of the base 10 and the fourth external connection terminal 64A of the fourth adjacent base 10 are electrically connected via the third connection part 67 and the fourth connection part 68 on the lower surface of the third ceramic layer 13A (the outer bottom surface of the sheet substrate 1A).

[0116] The fourth connection portion 68 of base 10 is connected to the third connection portion 67 of a predetermined base 10 adjacent to base 10 on the [B]-[C] side (the base 10 to the right of base 10 in Figure 12: here referred to as the "second adjacent base 10"). The fourth connection portion 68 of base 10 and the third connection portion 67 of the second adjacent base 10 straddle the boundary between base 10 and the second adjacent base 10 and form another connection portion that electrically connects the fourth external connection terminal 64A, which is the second external connection terminal of base 10, and the second external connection terminal 62A, which is the other external connection terminal for the piezoelectric vibrator of the second adjacent base 10. In other words, the fourth external connection terminal 64A of base 10 and the second external connection terminal 62A of the second adjacent base 10 are electrically connected by being connected via the connection portion on the lower surface of the third ceramic layer 13A (the outer bottom surface of the sheet substrate 1A).

[0117] The first external connection terminal 61, which is an external connection terminal for one piezoelectric vibrator of base 10, is electrically connected to the third external connection terminal 63, which is the first external connection terminal of base 10 that is adjacent to the base 10 on the [B]-[C] side among the multiple bases 10 (the base 10 to the right of base 10 in Figure 12).

[0118] The second external connection terminal 62A, which is an external connection terminal for the piezoelectric vibrator on the other side of base 10, is electrically connected to the fourth external connection terminal 64A, which is the second external connection terminal of base 10 that is adjacent to the [A]-[D] side of base 10 (the base 10 to the left of base 10 in Figure 12).

[0119] The third external connection terminal 63, which is the first external connection terminal of base 10, is electrically connected to the first external connection terminal 61, which is the external connection terminal for a piezoelectric vibrator of one of the base 10s adjacent to the base 10 on the [A]-[D] side (the base 10 to the left of the base 10 in Figure 12), among the multiple bases 10.

[0120] This is the second external connection terminal of base 10. 4th external connection terminal 64A This is the external connection terminal for the piezoelectric vibrator of the other base 10, which is the first base 10 adjacent to the [B]-[C] side of the base 10 in question (the base 10 to the right of the base 10 in Figure 12). Second external connection terminal 62A It is connected to and electrically connected to it.

[0121] Next, the configuration of the piezoelectric vibration device 100A manufactured by the piezoelectric vibration device manufacturing method according to a modified example of Embodiment 1 will be described using Figure 13. Figure 13 is a schematic cross-sectional view of the piezoelectric vibration device 100A according to a modified example of the embodiment.

[0122] As shown in Figure 13, the electro-vibration device 100A comprises a base 10, a piezoelectric vibrator 101 housed in a first cavity 18 of the base 10, and a lid 103 for hermetically sealing the piezoelectric vibrator 101 housed in the first cavity 18 of the base 10.

[0123] The piezoelectric vibrator 101 housed in the first cavity 18 has a pair of electrodes that are mechanically and electrically connected to a pair of electrode pads (first electrode pad 25, second electrode pad 26) on the base 10 using conductive joints 104 such as metal bumps and conductive adhesive.

[0124] Next, using the sheet substrate 1A described with reference to Figures 10 to 12, Piezoelectric vibration device 100A A method for manufacturing a piezoelectric vibration device according to this embodiment will be described. The method for manufacturing a piezoelectric vibration device includes a cutting step.

[0125] First, a molybdenum metallized layer is formed on each of the first ceramic layer 11, the second ceramic layer 12A, and the third ceramic layer 13A. Then, the first ceramic layer 11, the second ceramic layer 12A, and the third ceramic layer 13A are stacked. Next, grooves 11A and 11B are formed on the upper surface of the first ceramic layer 11 using a metal snap, laser snap, etc. (see Figure 1), and groove 13B is formed on the lower surface of the third ceramic layer 13A using a metal snap, laser snap, etc. (see Figure 2). Subsequently, nickel plating layers are stacked on the molybdenum metallized layers by firing the first to third ceramic layers 11 to 13A and electroplating, etc., and then a gold plating layer is stacked on the nickel plating layers using electroplating, etc. In this way, a sheet substrate 1A is manufactured.

[0126] Next, an energy beam (laser beam, electron beam, etc.) is irradiated onto the lower surface of the third ceramic layer 13A constituting the manufactured sheet substrate 1A along the boundary between adjacent bases 10. This forms a groove along the boundary between adjacent bases 10 on the lower surface of the third ceramic 13A (see dashed line in Figure 12), while physically cutting the connection portion connecting the adjacent first external connection terminal 61 and the third external connection terminal 63 (a connection portion formed from adjacent first connection portion 65 and second connection portion 66) and the connection portion connecting the adjacent second external connection terminal 62A and the fourth external connection terminal 64A (a connection portion formed from adjacent third connection portion 67 and fourth connection portion 68). This disconnects the electrical connections between the adjacent first external connection terminal 61 and third external connection terminal 63 and the second external connection terminal 62A and fourth external connection terminal 64A, thereby electrically isolating the first external connection terminal 61 and third external connection terminal 63 from the second external connection terminal 62A and fourth external connection terminal 64A (disconnection process).

[0127] The sheet substrate 1A, in which multiple (nine in this embodiment) bases 10 configured in this way are integrally connected, allows for the measurement of the characteristics of the piezoelectric vibration device 100 while suppressing the influence of other bases 10 by bringing a measurement probe into contact with the first external connection terminal 61 and the second external connection terminal 62A, which are electrically connected to the piezoelectric vibration piece 101 on each base 10.

[0128] Furthermore, the method for manufacturing a piezoelectric vibration device, the piezoelectric vibration device manufactured by said method, and the sheet substrate used in said manufacturing method are not limited to the method for manufacturing a piezoelectric vibration device, the piezoelectric vibration device 100 manufactured by said method, and the sheet substrates 1 and 1A used in said manufacturing method described above, and can be modified in various ways.

[0129] For example, in the above embodiment, the second external connection terminal 62 of the base 10 is not connected to any of the external connection terminals (first external connection terminal 61 to fourth external connection terminal 64A) of any base 10 adjacent to the base 10 on the lower surface of the third ceramic layer 13A (outer bottom surface of the sheet substrate 3), but the embodiment is not limited to this, and for example, the following may be the case. The second external connection terminal 62A of the base 10 may be electrically connected to the fourth external connection terminal 64A of the base 10 adjacent to the base 10 on the [D]-[A] side (the base 10 to the left of the base 10 in Figure 8: here referred to as the "fourth adjacent base 10") on the lower surface of the third ceramic layer 13A (outer bottom surface of the sheet substrate 1A). This electrical connection may also be realized by forming a connection portion (a connection portion with a similar configuration to the connection portion formed in the first connection portion 65 and the second connection portion 66 connected thereto) on the lower surface of the third ceramic layer 13A (the outer bottom surface of the sheet substrate 1A), which straddles the boundary between the base 10 and the fourth adjacent base 10 and connects the second external connection 62A of the base 10 to the fourth external connection terminal 64A of the fourth adjacent base 10. In this case, during the cutting process, the electrical connection between the first external connection terminal 61 of the base 10 and the third external connection terminal 63 of the base 10 on the [B]-[C] side of the base 10 may be cut, and the electrical connection between the second external connection terminal 62A of the base 10 and the fourth external connection terminal 64A of the fourth adjacent base 10 may also be cut. In this way, even with a sheet substrate 1A in which multiple bases 10 are integrally connected, the characteristics of the piezoelectric vibration device can be measured while suppressing the influence of other bases by bringing a measurement probe into contact with each of the pair of external connection terminals (first external connection terminal 61, second external connection terminal 62A) that are electrically connected to the piezoelectric vibration piece on each base 10.

[0130] In the above embodiment, an energy beam was used to cut the connection portion formed by the adjacent first connection portion 65 and second connection portion 66, but the invention is not limited to this, and for example, a cutting tool or the like may be used.

[0131] In the above embodiment, the energy beam is irradiated along the entire dotted line drawn in Figure 2, but the embodiment is not limited to this. For example, the energy beam may be irradiated only along a portion of the dotted line drawn in Figure 2, including the connection formed by the adjacent first connection portion 65 and second connection portion 66, to physically sever the connection portion.

[0132] In the above embodiment, in the third ceramic layer 13, the external connection terminals for the piezoelectric vibrator (a pair of first external connection terminals 61 and second external connection terminals 62A) and the external connection terminals (a pair of third external connection terminals 63 and fourth external connection terminals 64A) are electrically connected by connection portions formed from adjacent first connection portions 65 and second connection portions 66 and adjacent first connection portions 67 and second connection portions 68. However, in the third ceramic layer, the external connection terminals may be formed so as to straddle the portion between adjacent bases where no separation groove is formed. In other words, in the adjacent bases shown in Figure 12, adjacent external connection terminals may be connected to each other without the use of connection portions.

[0133] In the above embodiment, in the third ceramic layer 13, the external connection terminals for the piezoelectric vibrator (a pair of first external connection terminals 61 and second external connection terminals 62A) and the external connection terminals (a pair of third external connection terminals 63 and fourth external connection terminals 64A) are electrically connected by connection portions formed from adjacent first connection portions 65 and second connection portions 66 and adjacent first connection portions 67 and second connection portions 68. However, in the third ceramic layer, the external connection terminals may be formed so as to span across four adjacent bases that share one corner with each other. In other words, in a configuration where four adjacent bases share one corner with each other, adjacent external connection terminals may be connected to each other without the use of connection portions.

[0134] The above embodiment describes a piezoelectric vibration device 100 with a built-in thermistor 102 that houses a piezoelectric vibrator and a thermistor, but the contents of the above embodiment are also applicable to piezoelectric vibration devices that house only a piezoelectric vibrator.

[0135] In the above embodiment, the element mounted together with the piezoelectric vibrator 101 is a thermistor 102, but it is not limited to this, and may be other temperature sensors such as diodes, or integrated circuit elements (IC elements) that constitute an oscillation circuit together with the piezoelectric vibrator 101. Furthermore, in the modified embodiment 1 described above, a piezoelectric vibrator in which only the piezoelectric vibrator piece 101 is housed in the first cavity 18 was illustrated. However, this invention is not limited to piezoelectric vibrators, but can also be applied to piezoelectric oscillators that house integrated circuit elements (IC elements) that constitute an oscillation circuit together with the piezoelectric vibrator piece 101.

[0136] In the above embodiment, the structure of the base 10 (package structure) is an H-shaped structure in cross-sectional view, but it is not limited to this, and for example, as in the modified embodiment 1, it is open only at the top. First cavity 18 The piezoelectric vibration device may have a box-shaped structure in cross-section. Alternatively, the base 10 may be flat, with a piezoelectric vibrator and other electronic components (for example, an IC that forms an oscillation circuit together with the piezoelectric vibrator) mounted on one main surface of the substrate, and the piezoelectric vibrator and other electronic components mounted on one main surface of the substrate molded together with resin.

[0137] Furthermore, in a modified example of Embodiment 1, the piezoelectric vibration device 100A, in which only one main surface direction of the base 10 is open, has a piezoelectric vibrator 101 housed in the first cavity 18. However, the piezoelectric vibration device may also be configured to include a thermistor, integrated circuit, etc., along with the piezoelectric vibrator.

[0138] In the above embodiment, the piezoelectric vibrating piece 101 housed in the base 10 may be, for example, a flat piezoelectric vibrating plate, a piezoelectric vibrating plate with a mesa structure (a structure in which the central part is thicker than the outer part), or a piezoelectric vibrating plate with an inverse mesa structure (a structure in which the central part is thinner than the outer part). Alternatively, it may be a piezoelectric vibrating plate with a frame, in which a vibrating part (a region in which an excitation electrode is formed), an outer frame part thicker than the vibrating part that surrounds the vibrating part with a gap between them, and a connecting part that connects the vibrating part and the outer frame part are integrally molded. The shape of this vibrating part may be, for example, rectangular (AT cut, SC cut, etc.) or tuning fork shape (BT cut).

[0139] In the above embodiment, the piezoelectric vibrator 101 is housed in the base 10, but the embodiment is not limited to this, and for example, the base 10 may house a piezoelectric vibrator with a hermetically sealed vibrating part. This piezoelectric vibrator has, for example, a structure in which three quartz crystals are stacked (a structure in which flat sealing members are joined to the front and back of a quartz diaphragm that is integrally molded so as to surround the vibrating part with a frame).

[0140] In the above embodiment, the first external connection terminal 61 and the third external connection terminal 63 are connected by a connection formed from the first connection part 65 and the second connection part 66, and the second external connection terminal 62A and the fourth external connection terminal 64A are connected by a connection formed from the third connection part 67 and the fourth connection part 68. However, a configuration in which the first external connection terminal, the second external connection terminal, the third external connection terminal and the fourth external connection terminal are connected is also acceptable. In other words, any connection method that electrically connects the first external connection terminal, the second external connection terminal, the third external connection terminal and the fourth external connection terminal is acceptable.

[0141] Furthermore, the contents of the above embodiments and the contents of the modified examples may be combined as appropriate. [Industrial applicability]

[0142] The present invention relates to a method for manufacturing a piezoelectric vibration device, and to the method for manufacturing the said piezoelectric vibration device. This can be widely applied to piezoelectric vibration devices manufactured by this method, and to sheet substrates used in such manufacturing methods. [Explanation of symbols]

[0143] 1, 1A: Sheet substrate 10: Bass 11: First ceramic layer 11A, 11B, 13B: Groove 12, 12A: Second ceramic layer 13, 13A: Third ceramic layer 16, 17: Through hole 18: Cavity 19: Second Cavity 21: Metal layer 22: Electrode 25: First electrode pad 26: Second electrode pad 27a~30a, 36, 46~49: Through-hole connection electrodes 51a~54a: Through-hole connection electrodes 27b~30b: Through-hole electrodes 31: Wiring pattern for electrode pads 37: Support part 41: First electrode pad 42: Second electrode pad 43, 43A: First wiring pattern 44, 44A: Second wiring pattern 45: Third wiring pattern 61: First external connection terminal 62, 62A: Second external connection terminal 63: Third external connection terminal 64, 64A: 4th external connection terminal 65: First connection section 66: Second connection section 67: Third connection section 68: Fourth connection section 100, 100A: Piezoelectric vibration device 102: Thermistor 103: Lid 104: Conductive joint 105: Handa

Claims

1. A method for manufacturing piezoelectric vibration devices, comprising using a sheet substrate in which multiple rectangular bases in plan view, each containing at least one piezoelectric vibrator, are connected in a matrix and integrally molded, wherein multiple piezoelectric vibration devices are manufactured, the method comprising manufacturing multiple piezoelectric vibration devices, the method comprising: On the outer bottom surface of each of the bases, a plurality of external connection terminals are formed, spaced inward from the outer edge of the base in a plan view, including a pair of external connection terminals for piezoelectric vibrators for electrically connecting the piezoelectric vibrator housed in the base to the outside of the base. On the outer bottom surface of the sheet substrate, one of the pair of external connection terminals for piezoelectric vibrators on a predetermined base among the plurality of bases, and the first external connection terminal on a first base adjacent to the predetermined base among the plurality of bases, are electrically connected by a connection portion that straddles the boundary between the predetermined base and the first base. The aforementioned connection part is In the external connection terminal for the piezoelectric vibrator, it is connected to a portion of the base other than the corner furthest from the center of the outer bottom surface of the predetermined base, The method for manufacturing the piezoelectric vibration device is as follows: A method for manufacturing a piezoelectric vibration device, characterized in that, in the sheet substrate, the electrical connection between the one external connection terminal for the piezoelectric vibration piece and the first external connection terminal is severed using a cutting device, thereby electrically isolating the one external connection terminal for the piezoelectric vibration piece from the first external connection terminal.

2. The method for manufacturing a piezoelectric vibration device according to claim 1, characterized in that, on the outer bottom surface of the sheet substrate, the other external connection terminal for the piezoelectric vibration piece of the pair of external connection terminals for the piezoelectric vibration piece of the predetermined base is not electrically connected to any of the multiple external connection terminals of any of the bases adjacent to the predetermined base among the multiple bases.

3. On the outer bottom surface of the sheet substrate, the other external connection terminal for a pair of external connection terminals for a piezoelectric vibrator on a predetermined base among the plurality of bases is electrically connected to the second external connection terminal of a second base adjacent to the predetermined base among the plurality of bases. A method for manufacturing a piezoelectric vibration device according to claim 1, characterized in that, in the cutting step, the electrical connection between the other external connection terminal for the piezoelectric vibrator and the second external connection terminal in the sheet substrate is cut using a cutting device, thereby electrically isolating the other external connection terminal for the piezoelectric vibrator from the second external connection terminal.

4. Each of the plurality of external connection terminals relating to each of the bases is formed in a plan view spaced inward from the outer peripheral edge of the outer bottom surface of the base, On the outer bottom surface of the sheet substrate, a connection portion is formed that straddles the boundary between the predetermined base and the first base, and electrically connects one of the pair of external connection terminals for piezoelectric vibrators on the predetermined base to the first external connection terminal on the first base by physically connecting them. A method for manufacturing a piezoelectric vibration device according to claim 3, characterized in that a second connection portion is formed that straddles the boundary between the predetermined base and the second base, and electrically connects the other external connection terminal for a piezoelectric vibration piece of the pair of external connection terminals for a piezoelectric vibration piece of the predetermined base to the second external connection terminal of the second base by physically connecting them.

5. The method for manufacturing a piezoelectric vibration device according to claim 1, characterized in that no connection portion is formed on the outer bottom surface of the sheet substrate, which straddles the boundary between the predetermined base and any of the plurality of bases adjacent to the predetermined base, and electrically connects the other external connection terminal of the pair of external connection terminals for piezoelectric vibration pieces of the predetermined base to any of the plurality of external connection terminals of the base.

6. The sheet substrate is a laminate having a plurality of layers, including a layer on its outer bottom surface in which the plurality of external connection terminals of the base are formed, and one or more layers laminated on the side of the layer opposite to the outer bottom surface. A method for manufacturing a piezoelectric vibration device according to any one of claims 1 to 3, characterized in that a wiring pattern is formed between the laminations of the plurality of layers, straddling the boundary between the predetermined base and a base adjacent to the predetermined base among the plurality of bases.

7. The sheet substrate is a laminate having a plurality of layers, including a layer on its outer bottom surface in which the plurality of external connection terminals of the base are formed, and one or more layers laminated on the side of the layer opposite to the outer bottom surface. Between the layers of the plurality of layers, a wiring pattern is formed that spans the boundary between the predetermined base and the base adjacent to the predetermined base among the plurality of bases. A method for manufacturing a piezoelectric vibration device according to claim 1 or 5, characterized in that the other external connection terminal for a piezoelectric vibration piece of the pair of external connection terminals for a piezoelectric vibration piece of the predetermined base is electrically connected by the wiring pattern to a second external connection terminal of the plurality of external connection terminals of a second base adjacent to the predetermined base among the plurality of bases.

8. The method for manufacturing a piezoelectric vibration device according to claim 1 or 5, characterized in that the cutting step physically cuts at least the connecting portion along the boundary between the predetermined base and the first base.

9. The method for manufacturing a piezoelectric vibration device according to any one of claims 1 to 3, characterized in that the cutting device is a device that uses an energy beam.

10. A piezoelectric vibrator having a base that is rectangular in plan view and houses at least a piezoelectric vibrator, On the outer bottom surface of the base, there are a number of external connection terminals, including a pair of external connection terminals for piezoelectric vibrators, which are located spaced inward from the outer edge of the base in a plan view, for electrically connecting the piezoelectric vibrator housed in the base to the outside of the base. The pair of external connection terminals for piezoelectric vibrators are, A piezoelectric vibration device characterized by having a conductive connection portion extending from the center of the base's outer bottom surface to the outer edge of the base's outer bottom surface, except for the corner furthest from the center of the base's outer bottom surface.

11. A sheet substrate in which multiple rectangular bases, each containing at least a piezoelectric vibrator, are connected in a matrix and integrally molded, On the outer bottom surface of each of the bases, a plurality of external connection terminals are formed, spaced inward from the outer edge of the base in a plan view, including a pair of external connection terminals for piezoelectric vibrators for electrically connecting the piezoelectric vibrator housed in the base to the outside of the base. On the outer bottom surface of the sheet substrate, one of the pair of external connection terminals for piezoelectric vibrators on a predetermined base among the plurality of bases and the plurality of external connection terminals on a first base adjacent to the predetermined base are electrically connected by a connection portion that straddles the boundary between the predetermined base and the first base. The aforementioned connection part is A sheet substrate characterized in that the pair of external connection terminals for piezoelectric vibrators are connected to portions other than the corners furthest from the center of the outer bottom surface of the predetermined base.

12. The sheet substrate according to claim 11, characterized in that, on the outer bottom surface of the sheet substrate, the other external connection terminal for a pair of external connection terminals for a piezoelectric vibrator of a predetermined base among the plurality of bases is electrically connected to the second external connection terminal of a second base adjacent to the predetermined base among the plurality of bases.

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