Oscillator

Abstract

To provide an oscillator capable of reducing a temperature difference between a vibration element and a thermosensitive element.SOLUTION: An oscillator includes a package having an accommodation space, a resonator element bonded to the package via a first bonding member in the accommodation space, and a circuit board flip-chip mounted on the package via a conductive second bonding member in the accommodation space. And a circuit element including a temperature sensing element, an oscillation circuit, and a temperature compensation circuit disposed on a wiring surface side located on the second bonding member side, a connection pad disposed on a back surface side in a front-back relationship with the wiring surface, and a via penetrating the wiring surface and the back surface and connecting the temperature sensing element and the connection pad, in which the vibration element is located on the back surface side of the circuit element, and further includes a third bonding member disposed apart from the first bonding member, bonding the vibration element and the circuit element, and connecting the vibration element and the connection pad.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an oscillator. [Background technology]

[0002] The oscillator described in Patent Document 1 has a package including a base with a recess opening on its top surface and a lid bonded to the top surface of the base to seal the opening of the recess. The recess has a first recess opening on the top surface of the base and a second recess opening on the bottom surface of the first recess. The oscillator also has a piezoelectric diaphragm bonded to the bottom surface of the first recess and an integrated circuit element bonded to the bottom surface of the second recess. The integrated circuit element is bonded to the bottom surface of the second recess using face-down bonding technology, with its active circuit surface facing the bottom surface of the second recess. The piezoelectric diaphragm is bonded at its base end to the bottom surface of the first recess with a conductive resin adhesive and at its tip end to the inactive circuit surface of the integrated circuit element with a silicone-based resin adhesive. By bonding the tip end of the piezoelectric diaphragm to the integrated circuit element in this way, the gap dimension between the piezoelectric diaphragm and the integrated circuit element can be reliably maintained as designed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-142946 Summary of the Invention [Problem to be solved by the invention]

[0004] Although not specifically mentioned in Patent Document 1, if the oscillator is a temperature-compensated crystal oscillator (TCXO), bonding the piezoelectric diaphragm and integrated circuit element with a silicone-based resin adhesive can be expected to reduce the temperature difference between the piezoelectric diaphragm and the integrated circuit element through heat exchange between the piezoelectric diaphragm and the integrated circuit element via the silicone-based resin adhesive. However, in the oscillator of Patent Document 1, the active circuit surface of the integrated circuit element faces the bottom of the second recess, and the piezoelectric diaphragm is bonded to the inactive circuit surface, resulting in a separation between the temperature-sensing element formed on the active circuit surface and the point where the silicone-based resin adhesive comes into contact. Therefore, the effect of reducing the temperature difference between the piezoelectric diaphragm and the integrated circuit element cannot be fully achieved, and there is room for improvement. [Means for solving the problem]

[0005] The oscillator of the present invention comprises: a package having an accommodating space; a vibration element joined to the package via a first joining member in the accommodation space; a temperature-sensing element that is flip-chip mounted to the package within the accommodating space via a conductive second bonding member and that is disposed on a wiring surface that is located on the second bonding member side; an oscillation circuit that oscillates the vibration element to generate an oscillation signal; and a temperature compensation circuit that compensates for the frequency temperature characteristics of the oscillation signal based on the temperature detected by the temperature-sensing element; connection pads that are disposed on a back surface that is opposite to the wiring surface; and vias that penetrate the wiring surface and the back surface and connect the temperature-sensing element and the connection pads; the vibration element is located on the back surface side of the circuit element, The device further includes a third bonding member that is disposed apart from the first bonding member, bonds the vibration element and the circuit element, and connects the vibration element and the connection pad. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a cross-sectional view showing an oscillator according to a first embodiment. [Figure 2]FIG. [Figure 3] FIG. 10 is a top view showing a modified example of the oscillator. [Figure 4] FIG. 10 is a top view of an oscillator according to a second embodiment. [Figure 5] FIG. 10 is a cross-sectional view of an oscillator according to a third embodiment. [Figure 6] FIG. 10 is a cross-sectional view of an oscillator according to a fourth embodiment. [Figure 7] FIG. 2 is a cross-sectional view of a vibration element. [Figure 8] FIG. 2 is a top view showing the internal structure of the vibration element, with the upper lid layer not shown. DETAILED DESCRIPTION OF THE INVENTION

[0007] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the oscillator of the present invention will now be described in detail with reference to the accompanying drawings.

[0008] First Embodiment Fig. 1 is a cross-sectional view showing an oscillator according to a first embodiment, Fig. 2 is a top view of the oscillator, and Fig. 3 is a top view showing a modified example of the oscillator.

[0009] For ease of explanation, FIGS. 1 to 3 illustrate an X-axis, a Y-axis, and a Z-axis, which are perpendicular to each other. The direction along the X-axis is also referred to as the X-axis direction, the direction along the Y-axis as the Y-axis direction, and the direction along the Z-axis as the Z-axis direction. The arrowed side of each axis is also referred to as the "plus side," and the opposite side as the "minus side." The arrowed side of the Z-axis, which is the thickness direction of oscillator 1, is also referred to as the "upper side," and the opposite side as the "lower side."

[0010] The oscillator 1 shown in FIG. 1 is a TCXO (temperature compensated crystal oscillator), and has a package 2 having an accommodation space S, and a resonator element 5 and a circuit element 6 accommodated in the accommodation space S of the package 2.

[0011] The package 2 has a base substrate 3. The base substrate 3 is made of ceramics such as alumina. The base substrate 3 has an upper surface and a lower surface, which are opposite sides of the substrate. The base substrate 3 also has a recess 31 with a bottom that opens onto the upper surface. The recess 31 is made up of multiple recesses, including a first recess 311 that opens onto the upper surface, and a second recess 312 that opens onto the bottom of the first recess 311 and has a smaller opening than the first recess 311.

[0012] Furthermore, a pair of internal terminals 321 are arranged on the bottom surface of the first recess 311, a plurality of internal terminals 322 are arranged on the bottom surface of the second recess 312, and a plurality of external terminals 323 are arranged on the lower surface of the base substrate 3. Each of the internal terminals 321 and each of the external terminals 323 is electrically connected to the corresponding internal terminal 322 via internal wiring (not shown) formed in the base substrate 3.

[0013] The vibration element 5 is bonded to the bottom surface of the first recess 311 via a first bonding member B1 and is electrically connected to each of the internal terminals 321, while the circuit element 6 is bonded to the bottom surface of the second recess 312 via a second bonding member B2 and is electrically connected to each of the internal terminals 322. The vibration element 5 is located above the circuit element 6 (the positive side in the Z-axis direction), that is, on the side of a back surface 6b described later. In addition, in a plan view, that is, in a plan view from the Z-axis direction, the tip end (the end on the positive side in the X-axis direction) of the vibration element 5 overlaps with the circuit element 6, and the base end (the end on the negative side in the X-axis direction) located opposite the tip end overlaps with the bottom surface of the first recess 311 without overlapping with the circuit element 6.

[0014] The package 2 also has a lid 4. The lid 4 is made of a metal material such as Kovar. The lid 4 is bonded to the upper surface of the base substrate 3 via a bonding member and closes the opening of the recess 31. By closing the opening of the recess 31 with the lid 4 in this way, an airtight storage space S is formed inside the package 2. The resonator element 5 and the circuit element 6 are then housed in the storage space S. The storage space S is in a reduced pressure state, preferably a state closer to a vacuum. This reduces the CI (crystal impedance) value of the resonator element 5 and improves the oscillation characteristics. However, the atmosphere of the storage space S is not particularly limited.

[0015] 1, the circuit element 6 has a semiconductor substrate 60 having a wiring surface 6a as a first surface and a back surface 6b as a second surface opposite to the wiring surface 6a. Various circuit elements for configuring the necessary circuits are formed on the wiring surface 6a. In addition, a wiring layer 600 is formed on the wiring surface 6a to electrically connect the circuit elements to each other so that predetermined functions are performed, and further, a plurality of terminals 69 are arranged on the wiring layer 600 to electrically connect the circuit element 6 to internal terminals 322.

[0016] The circuit element 6 configured as above is flip-chip mounted on the bottom surface of the second recess 312. Specifically, the circuit element 6 is bonded to the bottom surface of the second recess 312 via a plurality of conductive second bonding members B2, with the wiring surface 6a facing downward, i.e., toward the bottom surface of the second recess 312. Furthermore, each connection terminal 69 is electrically connected to a corresponding internal terminal 322 via the second bonding members B2. The second bonding members B2 are various metal balls such as gold balls and copper balls. However, the configuration of the second bonding members B2 is not particularly limited as long as it is capable of flip-chip mounting.

[0017] The circuit element 6 also has a temperature sensing element 61, an oscillation circuit 62, and a temperature compensation circuit 63 arranged on the wiring surface 6a side. The temperature sensing element 61 is formed on the wiring surface 6a, and the oscillation circuit 62 and the temperature compensation circuit 63 are formed by electrically connecting the circuit elements formed on the wiring surface 6a via the wiring layer 600.

[0018] The temperature-sensing element 61 is, for example, a resistor (thin-film thermistor) whose resistance value changes according to temperature, and can detect temperature from the magnitude of the resistance value. The oscillation circuit 62 is electrically connected to the vibration element 5, amplifies the output signal of the vibration element 5, and feeds back the amplified signal to the vibration element 5, causing the vibration element 5 to oscillate and generate an oscillation signal. The temperature compensation circuit 63 compensates for the frequency-temperature characteristics of the oscillation signal generated by the oscillation circuit 62 based on the temperature detected by the temperature-sensing element 61. In other words, temperature compensation is performed so that the frequency fluctuation of the oscillation signal is smaller than the frequency-temperature characteristics of the vibration element 5 itself. With this configuration, frequency fluctuation of the oscillation signal due to temperature changes is suppressed, resulting in oscillator 1 with excellent oscillation characteristics.

[0019] The oscillator circuit 62 may be, for example, a Pierce oscillator circuit, an inverter oscillator circuit, a Colpitts oscillator circuit, a Hartley oscillator circuit, etc. The temperature compensation circuit 63 may be, for example, a circuit that adjusts the oscillation frequency of the oscillator circuit 62 by adjusting the capacitance of a variable capacitance circuit connected to the oscillator circuit 62, or a circuit that adjusts the frequency of the oscillation signal generated by the oscillator circuit 62 using a PLL circuit or a direct digital synthesizer circuit.

[0020] 1, the circuit element 6 has an insulating film 68 disposed on the back surface 6b and a connection pad 67 disposed on the insulating film 68. By disposing the connection pad 67 on the insulating film 68 in this manner, electrical conduction between the connection pad 67 and the semiconductor substrate 60 can be suppressed. The insulating film 68 is not particularly limited, and can be, for example, a silicon oxide film formed by thermal oxidation, sputtering, or the like. However, the present invention is not limited thereto, and for example, the insulating film 68 may be omitted, and the connection pad 67 may be disposed on the back surface 6b. Since the back surface 6b is a ground surface, in this case, the connection pad 67 is connected to the ground of the circuit element 6.

[0021] Furthermore, the connection pad 67 overlaps the tip of the vibration element 5 in a plan view from the Z-axis direction. The connection pad 67 also overlaps the temperature-sensing element 61 in a plan view from the Z-axis direction. The circuit element 6 also overlaps the temperature-sensing element 61 and has a via 66 that penetrates the wiring surface 6a and the back surface 6b. The temperature-sensing element 61 and the connection pad 67 are connected via the via 66. Note that in the illustrated configuration, two vias 66 are formed, but the number of vias 66 is not particularly limited. Furthermore, although not illustrated, an insulating film is formed between the via 66 and the semiconductor substrate 60 to insulate them from each other.

[0022] The connection pads 67 and the vias 66 are made of a material having a thermal conductivity higher than at least the constituent material of the semiconductor substrate 60. In this embodiment, the connection pads 67 and the vias 66 are made of a conductive material, specifically, various metal materials such as gold (Au), copper (Cu), and aluminum (Al). This results in the connection pads 67 and the vias 66 having high thermal conductivity. However, the constituent materials of the connection pads 67 and the vias 66 are not particularly limited. Furthermore, since the connection pads 67 and the vias 66 are not used for electrical connection, they may be made of an insulating material.

[0023] The vibration element 5 is an AT-cut quartz crystal vibration element. AT-cut quartz crystal vibration elements have third-order frequency-temperature characteristics and therefore excellent frequency stability. As shown in Figure 2, the vibration element 5 has a rectangular vibration substrate 51 cut out from quartz crystal by AT-cutting, and electrodes arranged on the surface of the vibration substrate 51.

[0024] The electrodes include a first excitation electrode 521 arranged on the upper surface of the vibrating substrate 51, and a second excitation electrode 531 arranged on the lower surface of the vibrating substrate 51 and facing the first excitation electrode 521 across the vibrating substrate 51. The electrodes also include a first connection terminal 522 and a second connection terminal 532 arranged side by side in the Y-axis direction on the edge of the lower surface of the vibrating substrate 51, a first escape wiring 523 that electrically connects the first excitation electrode 521 and the first connection terminal 522, and a second escape wiring 533 that electrically connects the second excitation electrode 531 and the second connection terminal 532.

[0025] However, the configuration of the vibration element 5 is not particularly limited. For example, the planar shape of the vibration substrate 51 is not limited to a rectangle and may be a circle. Furthermore, the portion sandwiched between the first and second excitation electrodes 521 and 531 may be a mesa type in which it is thicker and raised than the surrounding portions, or conversely, it may be an inverted mesa type in which it is thinner and depressed than the surrounding portions. Furthermore, in addition to an AT-cut quartz crystal vibration element, an SC-cut quartz crystal vibration element, a BT-cut quartz crystal vibration element, or a tuning fork-type quartz crystal vibration element may also be used as the vibration element 5. Furthermore, a surface acoustic wave resonator, other piezoelectric vibration elements, piezoelectric vibration elements made of piezoelectric materials other than a quartz crystal resonator, a MEMS (Micro Electro Mechanical Systems) resonator element, etc. may also be used.

[0026] The vibrating element 5 has a base end (the end on the negative side in the X-axis direction) joined to the bottom surface of the first recess 311 via a pair of conductive first bonding members B1. The first connecting terminal 522 and one of the internal terminals 321 are electrically connected via one of the first bonding members B1, and the second connecting terminal 532 and the other internal terminal 321 are electrically connected via the other first bonding member B1.

[0027] The first bonding member B1 is a conductive resin adhesive, and in this embodiment, a conductive epoxy adhesive is used, in which a metal filler such as Ag (silver) filler is dispersed in an epoxy resin. With this configuration, the first bonding member B1 is softer than when a metal bump or the like is used as the first bonding member B1, and can effectively absorb and relieve stress generated between the vibration element 5 and the base substrate 3. However, the configuration of the first bonding member B1 is not particularly limited.

[0028] 1 and 2, the oscillator 1 further includes a third bonding member B3 that is spaced apart from the first bonding member B1 and bonds the vibration element 5 and the circuit element 6. As described above, the tip of the vibration element 5 overlaps the circuit element 6 in a plan view from the Z-axis direction. The third bonding member B3 is located between the vibration element 5 and the circuit element 6 and bonds the lower surface of the vibration element 5 to the upper surface of the circuit element 6. Because the vibration element 5 and the circuit element 6 overlap in this way, the vibration element 5 and the connection pad 67 can be easily bonded by the third bonding member B3.

[0029] The third bonding member B3 has an upper end connected to the tip of the vibration substrate 51 and is not in contact with the electrodes arranged on the vibration substrate 51. The third bonding member B3 has a lower end connected to the connection pad 67 of the circuit element 6. With this configuration, the vibration element 5 and the temperature sensitive element 61 are thermally connected via the third bonding member B3, the connection pad 67, and the via 66. Therefore, the temperature difference between the vibration element 5 and the temperature sensitive element 61 can be further reduced.

[0030] The third bonding member B3 is a conductive resin adhesive. In particular, in this embodiment, similar to the first bonding member B1, an epoxy-based conductive adhesive is used, which is an epoxy-based resin with a metal filler such as Ag (silver) filler dispersed therein. This provides the third bonding member B3 with sufficiently high thermal conductivity, thereby minimizing the temperature difference between the vibration element 5 and the temperature-sensing element 61. Furthermore, compared to a case where a metal bump or the like is used, the third bonding member B3 is softer and can effectively absorb and alleviate stress generated between the vibration element 5 and the circuit element 6. However, the configuration of the third bonding member B3 is not particularly limited. Furthermore, since the third bonding member B3 is not used for electrical connection, it may be made of an insulating material.

[0031] To specifically explain how the temperature difference between the vibration element 5 and the thermosensitive element 61 can be kept small, the first bonding member B1 that bonds the base substrate 3 and the vibration element 5 is a conductive resin adhesive, while the second bonding member B2 that bonds the base substrate 3 and the circuit element 6 is a metal ball. Of these, the conductive resin adhesive tends to spread and be crushed when bonding the vibration element 5, resulting in a larger diameter than the metal ball. For example, the diameter of the first bonding member B1 is about 200 μm, and the diameter of the third bonding member B3 is about 50 μm.

[0032] Therefore, although the first bonding member B1 has a lower thermal conductivity than the second bonding member B2, the amount of heat transferred per unit time is greater for the first bonding member B1 than for the second bonding member B2. Therefore, heat from the base substrate 3 is more easily transferred to the vibration element 5 than to the circuit element 6, resulting in a temperature difference between the vibration element 5 and the circuit element 6. When a temperature difference occurs between the vibration element 5 and the circuit element 6, an error occurs between the actual temperature of the vibration element 5 and the compensation temperature used in the temperature compensation circuit 63, reducing the accuracy of the temperature compensation. Therefore, in the oscillator 1, the vibration element 5 and the temperature sensing element 61 are thermally connected via the third bonding member B3, the connection pad 67, and the via 66, thereby minimizing the temperature difference between them. This allows the temperature compensation circuit 63 to perform temperature compensation more accurately, resulting in a highly accurate oscillator 1.

[0033] In particular, in this embodiment, a conductive resin adhesive is used as the third bonding member B3. As described for the first bonding member B1, the conductive resin adhesive spreads and is crushed when bonding the vibration element 5 to the circuit element 6, increasing its diameter. For example, the diameter of the third bonding member B3 is approximately 200 μm, whereas if a metal bump were used, the diameter would be approximately 50 μm. Therefore, using a conductive resin adhesive for the third bonding member B3 promotes heat transfer between the vibration element 5 and the temperature sensing element 61, thereby further reducing the temperature difference between the vibration element 5 and the temperature sensing element 61.

[0034] In this embodiment, the third bonding member B3 is bonded to the tip end of the vibration substrate 51. As a result, the vibration element 5 is supported at both ends (the base end and the tip end) by the first and third bonding members B1 and B3. This stabilizes the posture of the vibration element 5, and effectively suppresses fluctuations in the oscillation characteristics of the vibration element 5. However, the bonding location of the third bonding member B3 is not particularly limited, and may be, for example, a lateral end of the vibration element 5 as shown in FIG. 3.

[0035] Furthermore, in this embodiment, the vibration element 5 and the connection pad 67 overlap in a plan view in the Z-axis direction, so the vibration element 5, the third bonding member B3, the connection pad 67, the via 66, and the temperature sensitive element 61 can be arranged in a straight line in the Z-axis direction. This makes it possible to shorten the heat path between the vibration element 5 and the temperature sensitive element 61, thereby further reducing the temperature difference between the vibration element 5 and the temperature sensitive element 61.

[0036] The oscillator 1 has been described above. As described above, the oscillator 1 includes a package 2 having an accommodation space S, a vibration element 5 bonded to the package 2 within the accommodation space S via a first bonding member B1, a temperature-sensing element 61 flip-chip mounted to the package 2 within the accommodation space S via a conductive second bonding member B2 and disposed on a wiring surface 6a side facing the second bonding member B2, an oscillation circuit 62 that oscillates the vibration element 5 to generate an oscillation signal, and a temperature compensation circuit 63 that compensates for the frequency-temperature characteristics of the oscillation signal based on the temperature detected by the temperature-sensing element 61, a connection pad 67 disposed on a back surface 6b opposite the wiring surface 6a, and a via 66 that penetrates the wiring surface 6a and the back surface 6b and connects the temperature-sensing element 61 to the connection pad 67. The vibration element 5 is also disposed on the back surface 6b side of the circuit element 6. The oscillator 1 further includes a third bonding member B3 that is disposed apart from the first bonding member B1, bonds the vibration element 5 to the circuit element 6, and connects the vibration element 5 to the connection pad 67. With this configuration, the vibration element 5 and the temperature sensitive element 61 are thermally connected via the third bonding member B3, the connection pad 67, and the via 66. Therefore, the temperature difference between the vibration element 5 and the temperature sensitive element 61 can be kept small.

[0037] Furthermore, as described above, in a plan view of the vibration element 5, that is, in a plan view from the Z-axis direction, the vibration element 5 and the connection pad 67 overlap each other. With this configuration, the vibration element 5 and the connection pad 67 can be easily bonded to each other by the third bonding member B3.

[0038] Furthermore, as described above, in a plan view of the vibration element 5, that is, in a plan view from the Z-axis direction, the vibration element 5, the third bonding member B3, the connection pad 67, the via 66, and the temperature sensitive element 61 overlap with each other. With this configuration, the heat path between the vibration element 5 and the temperature sensitive element 61 can be shortened, and the temperature difference between the vibration element 5 and the temperature sensitive element 61 becomes smaller.

[0039] As described above, the base end, which is one end of the vibration element 5, is joined to the package 2 via the first bonding member B1, and the tip end, which is the other end opposite the base end, is joined to the circuit element 6 via the third bonding member B3. With this configuration, the vibration element 5 is supported at both ends by the first and third bonding members B1 and B3. This stabilizes the posture of the vibration element 5, making it possible to effectively suppress fluctuations in the oscillation characteristics of the vibration element 5.

[0040] As described above, the first and third bonding members B1 and B3 are each made of a conductive resin adhesive. This configuration allows the thermal conductivity of the first and third bonding members B1 and B3 to be sufficiently increased. This allows the temperature difference between the vibration element 5 and the temperature sensing element 61 to be kept small.

[0041] As described above, the circuit element 6 has the insulating film 68 disposed on the rear surface 6b, and the connection pads 67 are disposed on the insulating film 68. This allows the semiconductor substrate 60 to be insulated from the connection pads 67. This effectively prevents unintended short circuits and the like, and improves the electrical stability of the oscillator 1.

[0042] Second Embodiment FIG. 4 is a top view of the oscillator according to the second embodiment.

[0043] The oscillator 1 according to this embodiment is similar to the oscillator 1 according to the first embodiment described above, except for the configuration of the joint between the vibration element 5 and the circuit element 6. Therefore, in the following description, differences between the oscillator 1 according to this embodiment and the first embodiment described above will be mainly described, and descriptions of similar points will be omitted. Furthermore, in the drawings of this embodiment, the same reference numerals are used to designate similar components to those in the previously described embodiment.

[0044] 4, the circuit element 6 is joined to the vibration element 5 via two third bonding members B3. Furthermore, the two third bonding members B3 are each in contact with the connection pads 67. This increases the amount of heat transferred through the thermal path connecting the vibration element 5 and the temperature sensitive element 61 compared to the first embodiment described above, and makes it possible to further reduce the temperature difference between the vibration element 5 and the temperature sensitive element 61.

[0045] The second embodiment can also achieve the same effects as the first embodiment described above.

[0046] <Third embodiment> FIG. 5 is a cross-sectional view of an oscillator according to the third embodiment.

[0047] The oscillator 1 according to this embodiment is similar to the oscillator 1 according to the first embodiment described above, except for the configuration of the circuit element 6. Therefore, in the following description, differences between the oscillator 1 according to this embodiment and the first embodiment described above will be mainly described, and descriptions of similar points will be omitted. Furthermore, in the drawings of this embodiment, the same reference numerals are used to designate the same components as those in the above-described embodiment.

[0048] 5, the circuit element 6 has two connection pads 67. Each connection pad 67 is connected to the temperature sensitive element 61 through a via 66. Each connection pad 67 is also joined to the vibration element 5 through a third joining member B3. With this configuration, multiple thermal paths are formed connecting the vibration element 5 and the temperature sensitive element 61, so the temperature difference between the vibration element 5 and the temperature sensitive element 61 can be kept smaller.

[0049] The third embodiment can also achieve the same effects as the first embodiment described above.

[0050] <Fourth embodiment> Fig. 6 is a cross-sectional view of an oscillator according to a fourth embodiment, Fig. 7 is a cross-sectional view of a vibration element, and Fig. 8 is a top view showing the internal structure of the vibration element, with the upper lid layer not shown.

[0051] The oscillator 1 according to this embodiment is similar to the oscillator 1 of the first embodiment described above, except that it uses a vibration element 7 instead of the vibration element 5. Therefore, in the following description, differences between the oscillator 1 of this embodiment and the first embodiment described above will be mainly described, and descriptions of similar points will be omitted. Furthermore, in each drawing of this embodiment, the same reference numerals are used to designate the same components as those in the above-described embodiment.

[0052] As shown in Fig. 6, the oscillator 1 has a vibrating element 7 housed in a package 2. As shown in Fig. 7, the vibrating element 7 has a device layer 71, and a lower lid layer 72 and an upper lid layer 73 that sandwich the device layer 71 from above and below. These three layers 71, 72, and 73 are each made of an AT-cut quartz crystal substrate.

[0053] 7 and 8, the device layer 71 has a frame-shaped frame portion 711, a vibration substrate 712 arranged inside the frame portion 711, and a connection portion 713 that connects the frame portion 711 and the vibration substrate 712. A first excitation electrode 751 is formed on the upper surface of the vibration substrate 712, and a second excitation electrode 761 is formed on the lower surface of the vibration substrate 712. A lower lid layer 72 is bonded to the lower surface of the frame portion 711. The lower lid layer 72 has an opening on its upper surface and a recess 721 for avoiding contact with the vibration substrate 712. A first connection terminal 752 and a second connection terminal 762 are formed on the lower surface of the lower lid layer 72. The first excitation electrode 751 and the first connection terminal 752 are electrically connected by a first extraction electrode 753 and a via (not shown), and the second excitation electrode 761 and the second connection terminal 762 are electrically connected by a second extraction electrode 763 and a via (not shown). The upper lid layer 73 is bonded to the upper surface of the frame portion 711. The upper lid layer 73 has an opening on its lower surface and a recess 731 for avoiding contact with the vibration substrate 712.

[0054] The inside of the vibration element 7 is in a reduced pressure state, preferably a state closer to a vacuum. This reduces the CI (crystal impedance) value of the vibration element 7, improving the oscillation characteristics. However, the atmosphere of the accommodation space S is not particularly limited.

[0055] 8, the vibration element 7 is bonded to the bottom surface of the first recess 311 at the base end of the lower lid layer 72 via a pair of first bonding members B1, and is electrically connected to the internal terminals 321. Furthermore, the vibration element 7 is bonded to the connection pads 67 on the circuit element 6 at the tip end of the lower lid layer 72 via a third bonding member B3.

[0056] In the oscillator 1 of the first embodiment described above, the oscillation characteristics of the vibrating element 5 cannot be inspected until the vibrating element 5 and the circuit element 6 are mounted on the base substrate 3. Therefore, if the vibrating element 5 does not pass the inspection, not only the vibrating element 5 but also the circuit element 6 and the base substrate 3 are wasted. In contrast, according to the oscillator 1 of this embodiment, the vibration characteristics of the vibrating element 7 can be inspected before the vibrating element 7 and the circuit element 6 are mounted on the base substrate 3. Therefore, only non-defective products that pass the inspection can be bonded to the base substrate 3. Therefore, the package 2 and the circuit element 6 are unlikely to be wasted, which reduces the manufacturing cost of the oscillator 1 and improves the yield.

[0057] The fourth embodiment can also achieve the same effects as the first embodiment.

[0058] Although the oscillator of the present invention has been described above based on the illustrated embodiment, the present invention is not limited to this, and the configuration of each part can be replaced with any configuration having a similar function. Also, other arbitrary components may be added to the present invention. Furthermore, the above-described embodiments may be combined as appropriate. [Explanation of symbols]

[0059] 1...oscillator, 2...package, 3...base substrate, 31...recess, 311...first recess, 312...second recess, 321...internal terminal, 322...internal terminal, 323...external terminal, 4...lid, 5...vibration element, 51...vibration substrate, 521...first excitation electrode, 522...first connection terminal, 523...first lead-out wiring, 531...second excitation electrode, 532...second connection terminal, 533...second lead-out wiring, 6...circuit element, 6a...wiring surface, 6b...back surface, 60...semiconductor substrate, 600...wiring layer, 61...thermosensitive element, 62...oscillating circuit, 6 3...Temperature compensation circuit, 66...Via, 67...Connection pad, 68...Insulating film, 69...Terminal, 7...Vibration element, 71...Device layer, 711...Frame portion, 712...Vibration substrate, 713...Connection portion, 72...Lower lid layer, 721...Recess, 73...Upper lid layer, 731...Recess, 751...First excitation electrode, 752...First pad electrode, 753...First extraction electrode, 761...Second excitation electrode, 762...Second pad electrode, 763...Second extraction electrode, B1...First bonding member, B2...Second bonding member, B3...Third bonding member, S...Accommodation space

Claims

1. a package having a storage space; a vibration element joined to the package via a first joining member in the accommodation space; a circuit element that is flip-chip mounted to the package within the accommodating space via a conductive second bonding member and that is arranged on a wiring surface side that is located on the second bonding member side; an oscillation circuit that oscillates the vibration element to generate an oscillation signal; and a temperature compensation circuit that compensates for the frequency temperature characteristics of the oscillation signal based on the temperature detected by the temperature sensing element; connection pads that are arranged on a back surface that is opposite to the wiring surface; and vias that penetrate the wiring surface and the back surface and connect the temperature sensing element and the connection pads; the vibration element is located on the back surface side of the circuit element, The oscillator further comprises a third bonding member arranged at a distance from the first bonding member, bonding the vibration element and the circuit element together, and connecting the vibration element and the connection pad together.

2. In a plan view of the vibration element, The oscillator according to claim 1 , wherein the vibration element and the connection pad overlap.

3. In a plan view of the vibration element, The oscillator according to claim 2 , wherein the vibration element, the third bonding member, the connection pad, the via, and the temperature-sensing element are overlapped with each other.

4. An oscillator as described in claim 1, wherein one end of the vibration element is joined to the package via the first joining member, and the other end opposite to the one end is joined to the circuit element via the third joining member.

5. The oscillator according to claim 1 , wherein the first bonding member and the third bonding member are each made of a conductive resin adhesive.

6. the circuit element has an insulating film disposed on the back surface, The oscillator according to claim 1 , wherein the connection pads are disposed on the insulating film.

7. one end of the vibration element is joined to the package via the first bonding member, and the other end opposite to the one end is joined to the connection pad via the third bonding member; the first bonding member and the third bonding member are each a conductive resin adhesive, The oscillator according to claim 1 , wherein the vibration element, the third bonding member, the connection pad, the via, and the temperature-sensing element overlap each other in a plan view of the vibration element.

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