Oscillator

Abstract

To provide an oscillator which has a small parasitic capacitance and is advantageous for increasing an output frequency.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 disposed in the accommodation space and flip-chip mounted on the package via a conductive second bonding member. A circuit element including an oscillation circuit disposed on a wiring surface side located on a second bonding member side and configured to oscillate a vibrating element to generate an oscillation signal, and an electrode pad disposed on a back surface side having a front-back relationship with the wiring surface, and a first via penetrating the wiring surface and the back surface and electrically connecting the oscillation circuit and the electrode pad, wherein the vibrating element is located on the back surface side of the circuit element, and further includes a conductive third bonding member that bonds the vibrating element and the circuit element and electrically connects the vibrating element and the electrode pad.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] The crystal oscillator described in Patent Document 1 has a package including a base with a recessed portion opening on its top surface and a lid bonded to the top surface of the base to seal the opening of the recessed portion. The recessed portion has a first recessed portion opening on the top surface of the base and a second recessed portion opening on the bottom surface of the first recess. The crystal oscillator further includes 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] With the recent increase in communication speed, the output frequency of crystal oscillators is becoming higher and higher. However, in the crystal oscillator of Patent Document 1, the piezoelectric diaphragm and the integrated circuit element are electrically connected via the base, which results in a long electrical path and tends to increase parasitic capacitance. Therefore, there is a problem that this oscillator is not suitable for increasing the output frequency. [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 circuit element including: an oscillator circuit that is disposed within the accommodating space, is flip-chip mounted to the package via a conductive second bonding member, is disposed on a wiring surface side that is located on the second bonding member side, and oscillates the vibration element to generate an oscillation signal; an electrode pad that is disposed on a back surface that is opposite to the wiring surface; and a first via that penetrates the wiring surface and the back surface and electrically connects the oscillator circuit and the electrode pad; the vibration element is located on the back surface side of the circuit element, The display device further includes a conductive third bonding member that bonds the vibration element and the circuit element together and electrically connects the vibration element and the electrode pad together. [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. 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] FIG. [Figure 5] FIG. 10 is a top view of a circuit element included in the oscillator according to the second embodiment. [Figure 6] FIG. 6 is a cross-sectional view taken along line BB in FIG. 5. [Figure 7] FIG. 10 is a cross-sectional view of an oscillator according to a third embodiment. [Figure 8] FIG. 2 is a cross-sectional view of a vibration element. [Figure 9] 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 a circuit element. Fig. 3 is a cross-sectional view taken along line AA in Fig. 2. Fig. 4 is a top view of a vibration element.

[0009] For ease of explanation, FIGS. 1 to 4 illustrate an X-axis, a Y-axis, and a Z-axis that 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 base substrate 3. The base substrate 3 also has a recess 31 with a bottom that opens on the upper surface. The recess 31 is made up of multiple recesses, and has a first recess 311 that opens on the upper surface, and a second recess 312 that opens on the bottom of the first recess 311 and has a smaller opening than the first recess 311.

[0012] Furthermore, 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 external terminal 323 is electrically connected to a corresponding internal terminal 322 via internal wiring (not shown) formed within 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 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 internal terminal 322. The vibration element 5 is located above the circuit element 6, that is, on the back surface 6b side described later. In plan view from the Z axis direction, the base 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 tip end (the end on the negative side in the X axis direction) located opposite the base 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 its lower surface and a back surface 6b as its upper surface opposite to the wiring surface 6a. A plurality of various circuit elements (not shown) for configuring the necessary circuits are formed on the wiring surface 6a. 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. Furthermore, a plurality of connection terminals 69 are arranged on the wiring layer 600 to electrically connect the circuit element 6 to the 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 rear surface 6b and a pair of electrode pads 67 disposed on the insulating film 68. By disposing each electrode pad 67 on the insulating film 68 in this manner, each electrode pad 67 can be easily insulated from the rear surface 6b, which is the ground surface. The insulating film 68 is not particularly limited, but can be, for example, a silicon oxide film formed by thermal oxidation, sputtering, or the like.

[0021] 2, the pair of electrode pads 67 are arranged side by side in the Y-axis direction. Furthermore, each of the pair of electrode pads 67 overlaps the base end of the vibration element 5 in a plan view from the Z-axis direction. Furthermore, as shown in FIG. 3, the circuit element 6 has a pair of first vias 66 that penetrate the wiring surface 6a and the back surface 6b and electrically connect each electrode pad 67 to the oscillation circuit 62. Although not shown, an insulating film is formed between the first vias 66 and the semiconductor substrate 60 to insulate them. The electrode pads 67 and the first vias 66 are made of various metal materials, such as gold (Au), copper (Cu), and aluminum (Al).

[0022] 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 4, the vibration element 5 has a rectangular plate-shaped vibration substrate 51 cut out from quartz crystal using an AT cut method, and has a bottom surface 51a as a first surface and a top surface 51b as a second surface, which are opposite sides of the vibration substrate 51, and electrodes arranged on the surface of the vibration substrate 51.

[0023] The electrodes include a first excitation electrode 521 arranged on the lower surface 51a of the vibrating substrate 51, and a second excitation electrode 531 arranged on the upper surface 51b 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 at the base end of the lower surface of the vibrating substrate 51, a first escape wiring 523 electrically connecting the first excitation electrode 521 and the first connection terminal 522, and a second escape wiring 533 electrically connecting the second excitation electrode 531 and the second connection terminal 532.

[0024] 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, as the vibration element 5, 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. Furthermore, a surface acoustic wave resonator, other piezoelectric vibration elements, piezoelectric vibration elements made of piezoelectric materials other than a quartz crystal vibration element, a MEMS (Micro Electro Mechanical Systems) resonator element, or the like may also be used.

[0025] The vibrating element 5 is bonded at its base end (the end on the positive side in the X-axis direction) to the upper surface of the circuit element 6 via a pair of conductive third bonding members B3. The first connection terminal 522 is electrically connected to one of the electrode pads 67 via one of the third bonding members B3, and the second connection terminal 532 is electrically connected to the other of the electrode pads 67 via the other of the third bonding members B3. This electrically connects the vibrating element 5 to the oscillator circuit 62 of the circuit element 6 via the third bonding member B3. This configuration allows for a simple electrical connection between the vibrating element 5 and the oscillator circuit 62. Furthermore, compared to a conventional configuration in which the vibrating element 5 and the circuit element 6 are electrically connected via the base substrate 3, the electrical path between the vibrating element 5 and the oscillator circuit 62 can be shortened, thereby reducing parasitic capacitance. This results in an oscillator 1 suitable for increasing the frequency of oscillation signals.

[0026] In particular, in this embodiment, in a plan view from the Z-axis direction, the base end of the vibration element 5 overlaps with the circuit element 6, and further overlaps with the electrode pad 67. Therefore, the vibration element 5 and the circuit element 6 can be easily mechanically joined and electrically connected using the third bonding member B3. Furthermore, the vibration element 5 and the oscillation circuit 62 can be electrically connected over approximately the shortest distance, and parasitic capacitance can be further reduced.

[0027] The third bonding member B3 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 third bonding member B3 is softer than when a metal bump or the like is used as the third bonding member B3, and can effectively absorb and alleviate thermal 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.

[0028] Furthermore, the oscillator 1 has a first bonding member B1 that bonds the vibration element 5 to the base substrate 3. As described above, in a plan view from the Z-axis direction, the tip of the vibration element 5 does not overlap the circuit element 6 but overlaps the bottom surface of the first recess 311. The first bonding member B1 is disposed between the vibration element 5 and the bottom surface of the first recess 311, and bonds the lower surface of the vibration substrate 51 to the bottom surface of the first recess 311. In this way, because the vibration element 5 overlaps the bottom surface of the first recess 311, the vibration element 5 can be easily bonded to the base substrate 3 by the first bonding member B1.

[0029] As described above, the vibration element 5 is bonded to the circuit element 6 at its base end and to the base substrate 3 at its tip end. This stabilizes the posture of the vibration element 5, and effectively suppresses fluctuations in the oscillation characteristics of the vibration element 5. In particular, in this embodiment, both ends of the vibration element 5 are supported by the first and third bonding members B1 and B3, making the above-mentioned effects more pronounced. However, the bonding locations of the first and third bonding members B1 and B3 are not particularly limited.

[0030] Furthermore, by bonding the vibration element 5 and the base substrate 3 with the first bonding member B1, the temperature difference between the vibration element 5 and the temperature sensitive element 61 can be kept small, allowing for more accurate temperature compensation by the temperature compensation circuit 63. Specifically, in the oscillator 1, heat outside the package 2 is transferred from the base substrate 3 to the circuit element 6 via the second bonding member B2, and then to the vibration element 5 via the first bonding member B1. In this way, heat outside the package 2 is transferred to both the vibration element 5 and the circuit element 6 via the base substrate 3, allowing for less temperature difference between the vibration element 5 and the temperature sensitive element 61, allowing for more accurate temperature compensation by the temperature compensation circuit 63. Furthermore, because the vibration element 5 and the circuit element 6 are bonded via the third bonding member B3, heat exchange between the vibration element 5 and the circuit element 6 occurs via the third bonding member B3, further reducing the temperature difference therebetween.

[0031] The first bonding member B1 is a conductive resin adhesive. In particular, in this embodiment, similar to the third bonding member B3, a conductive epoxy adhesive is used, which is an epoxy resin with a metal filler, such as Ag (silver) filler, dispersed therein. This provides the first bonding member B1 with sufficiently high thermal conductivity, facilitating heat transfer from the base substrate 3 to the vibration element 5. Furthermore, compared to, for example, a metal bump, the first bonding member B1 is softer, allowing it to effectively absorb and alleviate thermal stress generated between the vibration element 5 and the base substrate 3. Furthermore, the conductive resin adhesive increases in diameter as it spreads and is crushed when bonding the vibration element 5 to the base substrate 3. For example, the diameter of the first bonding member B1 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 first bonding member B1 results in a lower thermal conductivity than using a metal bump, but increases the amount of heat transfer. Therefore, heat outside the package 2 is more easily transferred to the vibration element 5 via the base substrate 3. However, the configuration of the first bonding member B1 is not particularly limited. In addition, since the first bonding member B1 is not used for electrical connection, it may be made of an insulating material.

[0032] The above has described the oscillator 1. As described above, such an 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; an oscillation circuit 62 disposed within the accommodation space S and flip-chip mounted to the package 2 via a conductive second bonding member B2; an oscillation circuit 62 disposed on a wiring surface 6a side facing the second bonding member B2 and configured to oscillate the vibration element 5 to generate an oscillation signal; an electrode pad 67 disposed on a back surface 6b opposite the wiring surface 6a; and a first via 66 penetrating the wiring surface 6a and the back surface 6b and electrically connecting the oscillation circuit 62 and the electrode pad 67; and a vibration element 5 disposed on the back surface 6b of the circuit element 6 and further including a conductive third bonding member B3 bonding the vibration element 5 to the circuit element 6 and electrically connecting the vibration element 5 to the electrode pad 67. According to this configuration, the electrical path between the vibration element 5 and the oscillation circuit 62 can be shortened, and parasitic capacitance can be reduced accordingly, compared to a conventional configuration in which the vibration element 5 and the circuit element 6 are electrically connected via the base substrate 3. Therefore, the oscillator 1 is suitable for increasing the frequency of the oscillation signal.

[0033] As described above, the vibration element 5 includes the vibration substrate 51 having a lower surface 51a as a first surface located on the circuit element 6 side and an upper surface 51b as a second surface opposite the lower surface 51a, a first excitation electrode 521 arranged on the lower surface 51a, a second excitation electrode 531 arranged on the upper surface 51b and facing the first excitation electrode 521 across the vibration substrate 51, a first connection terminal 522 arranged on the lower surface 51a and electrically connected to the first excitation electrode 521, and a second connection terminal 532 arranged on the lower surface 51a and electrically connected to the second excitation electrode 531. The third bonding members B3 and the electrode pads 67 are arranged in pairs, and the first connection terminal 522 and one electrode pad 67 are electrically connected by one third bonding member B3, and the second connection terminal 532 and the other electrode pad 67 are electrically connected by the other third bonding member B3. According to this configuration, the vibration element 5 and the oscillation circuit 62 can be electrically connected with a simple configuration.

[0034] As described above, the vibration element 5 is joined to the circuit element 6 at one end, i.e., the base end, via the third bonding member B3, and is joined to the package 2 at the other end, i.e., the tip end, located opposite the base end, via the first bonding member B1. With this configuration, the posture of the vibration element 5 is stable, and fluctuations in the oscillation characteristics of the vibration element 5 can be effectively suppressed.

[0035] 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 base end of the vibration element 5 overlaps with the circuit element 6, but the tip end does not overlap with the circuit element 6. With this configuration, it becomes easier to join the base end of the vibration element 5 to the circuit element 6 and easier to join the tip end to the package 2.

[0036] As described above, the circuit element 6 has the temperature sensing element 61 arranged on the wiring surface 6a side and the 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. With this configuration, the frequency fluctuation of the oscillation signal due to temperature changes is suppressed, resulting in the oscillator 1 having excellent oscillation characteristics.

[0037] As described above, the circuit element 6 has the insulating film 68 disposed on the rear surface 6b, and the electrode pads 67 are disposed on the insulating film 68. With this simple configuration, the electrode pads 67 can be insulated from the rear surface 6b.

[0038] Second Embodiment Fig. 5 is a top view of a circuit element included in an oscillator according to a second embodiment, and Fig. 6 is a cross-sectional view taken along line BB in Fig. 5.

[0039] The oscillator 1 according to this embodiment is similar to the oscillator 1 according to the first embodiment, except that the vibration element 5 and the temperature-sensitive element 61 are thermally connected. Therefore, in the following description, differences between the oscillator 1 according to this embodiment and the first embodiment 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.

[0040] As shown in FIG. 5, the circuit element 6 has connection pads 65 arranged on the back surface 6b side. The connection pads 65 are arranged on an insulating film 68, similar to the electrode pads 67. The connection pads 65 are also arranged spaced apart from the electrode pads 67. This configuration makes it possible to easily insulate the connection pads 65 from the back surface 6b and the electrode pads 67. As shown in FIG. 6, the circuit element 6 has second vias 64 that penetrate the wiring surface 6a and the back surface 6b and connect the connection pads 65 to the temperature sensing element 61. Although not shown, an insulating film is formed between the second vias 64 and the semiconductor substrate 60, insulating them from each other.

[0041] The connection pads 65 and the second vias 64 are made of a material having a thermal conductivity higher than that of the constituent material of the semiconductor substrate 60. In this embodiment, the connection pads 65 and the second vias 64 are made of a conductive material, specifically, various metal materials such as gold (Au), copper (Cu), and aluminum (Al), similar to the electrode pads 67 and the first vias 66. This results in the connection pads 65 and the second vias 64 having high thermal conductivity and allows them to be formed simultaneously with the electrode pads 67 and the first vias 66. However, the constituent materials of the connection pads 65 and the second vias 64 are not particularly limited. Furthermore, since the connection pads 65 and the second vias 64 are not used for electrical connection, they may be made of an insulating material.

[0042] 5 and 6, the oscillator 1 has a fourth bonding member B4 that bonds the vibration element 5 and the connection pad 65. This thermally connects the vibration element 5 and the temperature sensitive element 61 via the fourth bonding member B4, the connection pad 65, and the second via 64. Therefore, compared to the first embodiment described above, the temperature difference between the vibration element 5 and the temperature sensitive element 61 can be further reduced. The fourth bonding member B4 is bonded to the lower surface 51a of the vibration substrate 51 and is not in contact with the electrodes.

[0043] The fourth bonding member B4 is a conductive resin adhesive. In particular, in this embodiment, similar to the first and third bonding members B1 and B3, 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 fourth bonding member B4 with sufficiently high thermal conductivity, allowing for efficient heat exchange between the vibration element 5 and the temperature-sensing element 61, thereby minimizing the temperature difference between them. Furthermore, compared to, for example, metal bumps, the fourth bonding member B4 is softer, allowing it to effectively absorb and alleviate stress generated between the vibration element 5 and the circuit element 6. However, the configuration of the fourth bonding member B4 is not particularly limited. Furthermore, since the fourth bonding member B4 is not used for electrical connection, it may be made of an insulating material.

[0044] In particular, in this embodiment, the vibration element 5, connection pad 65, second via 64, and temperature sensitive element 61 overlap in a plan view from the Z-axis direction. Therefore, the vibration element 5 and the temperature sensitive element 61 can be thermally connected over approximately the shortest distance, and the temperature difference between the vibration element 5 and the temperature sensitive element 61 can be further reduced. However, the arrangement of each part is not particularly limited.

[0045] As described above, in the oscillator 1 of this embodiment, the circuit element 6 has the connection pad 65 arranged on the back surface 6b, and the second via 64 that penetrates between the wiring surface 6a and the back surface 6b and connects the connection pad 65 and the temperature-sensitive element 61. The oscillator 1 also has a fourth bonding member B4 that bonds the vibration element 5 and the connection pad 65. With this configuration, the vibration element 5 and the temperature-sensitive element 61 are thermally connected via the fourth bonding member B4, the connection pad 65, and the second via 64. Therefore, for example, compared to the first embodiment described above, the temperature difference between the vibration element 5 and the temperature-sensitive element 61 can be further reduced.

[0046] 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 connection pad 65, the second via 64, and the temperature sensitive element 61 overlap. With this configuration, the vibration element 5 and the temperature sensitive element 61 can be thermally connected over approximately the shortest distance, and the temperature difference between the vibration element 5 and the temperature sensitive element 61 can be kept small.

[0047] The second embodiment can also achieve the same effects as the first embodiment described above.

[0048] Third Embodiment Fig. 7 is a cross-sectional view of an oscillator according to a third embodiment, Fig. 8 is a cross-sectional view of a vibration element, and Fig. 9 is a top view showing the internal structure of the vibration element, with the upper lid layer not shown.

[0049] 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.

[0050] As shown in Fig. 7, the oscillator 1 has a vibrating element 7 housed in a package 2. As shown in Fig. 8, 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.

[0051] 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 lower surface of the vibration substrate 712, and a second excitation electrode 761 is formed on the upper 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 escape wiring 753 and a via (not shown), and the second excitation electrode 761 and the second connection terminal 762 are electrically connected by a second escape wiring 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.

[0052] 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.

[0053] 9, the vibration element 7 is bonded to the upper surface of the circuit element 6 at the base end of the lower lid layer 72 via a pair of third bonding members B3, and is electrically connected to the electrode pad 67. Furthermore, the vibration element 7 is bonded to the bottom surface of the first recess 311 at the tip end of the lower lid layer 72 via a first bonding member B1.

[0054] 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, and 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 less likely to be wasted, and the manufacturing cost of the oscillator 1 can be reduced and the yield can be improved.

[0055] The third embodiment can also achieve the same effects as the first embodiment.

[0056] 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]

[0057] 1...oscillator, 2...package, 3...base substrate, 31...recess, 311...first recess, 312...second recess, 322...internal terminal, 323...external terminal, 4...lid, 5...vibration element, 51...vibration substrate, 51a...bottom surface, 51b...top surface, 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...oscillation circuit, 63...temperature compensation circuit, 64 ...second via, 65...connection pad, 66...first via, 67...electrode 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 connection terminal, 753...first lead-out wiring, 761...second excitation electrode, 762...second connection terminal, 763...second lead-out wiring, B1...first bonding member, B2...second bonding member, B3...third bonding member, B4...fourth 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 including: an oscillator circuit that is disposed within the accommodation space, is flip-chip mounted to the package via a conductive second bonding member, is disposed on a wiring surface side that is located on the second bonding member side, and oscillates the vibration element to generate an oscillation signal; an electrode pad that is disposed on a back surface that is opposite to the wiring surface; and a first via that penetrates the wiring surface and the back surface and electrically connects the oscillator circuit and the electrode pad; the vibration element is located on the back surface side of the circuit element, The oscillator further comprises a conductive third bonding member that bonds the vibration element and the circuit element and electrically connects the vibration element and the electrode pad.

2. The vibration element includes a vibration substrate having a first surface located on the circuit element side and a second surface opposite to the first surface, a first excitation electrode disposed on the first surface, a second excitation electrode disposed on the second surface and facing the first excitation electrode via the vibration substrate, a first connection terminal disposed on the first surface and electrically connected to the first excitation electrode, and a second connection terminal disposed on the first surface and electrically connected to the second excitation electrode, 2. The oscillator described in claim 1, wherein the third bonding members and the electrode pads are each arranged in pairs, one of the third bonding members electrically connecting the first connection terminal to one of the electrode pads, and the other of the third bonding members electrically connecting the second connection terminal to the other of the electrode pads.

3. 2. The oscillator according to claim 1, wherein the vibration element is joined to the circuit element at one end via the third joining member, and is joined to the package at the other end opposite the one end via the first joining member.

4. In a plan view of the vibration element, the one end overlaps the circuit element, 4. The oscillator according to claim 3, wherein the other end does not overlap the circuit element.

5. 2. The oscillator according to claim 1, wherein the circuit element includes a temperature-sensing element disposed on the wiring surface side 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.

6. the circuit element has an insulating film disposed on the back surface, 2. The oscillator according to claim 1, wherein the electrode pad is disposed on the insulating film.

7. the circuit element has a connection pad arranged on the back surface side, and a second via that penetrates the wiring surface and the back surface and connects the connection pad and the temperature sensing element, The oscillator according to claim 5 , further comprising a fourth bonding member bonding the vibration element and the connection pad.

8. In a plan view of the vibration element, The oscillator according to claim 7 , wherein the vibration element, the connection pad, the second via, and the temperature-sensing element overlap each other.

9. In a plan view of the vibration element, one end of the vibration element overlaps with the circuit element, and the other end of the vibration element does not overlap with the circuit element, the vibration element is joined at the one end to the circuit element via the third joining member, and at the other end to the package via the first joining member; 3. The oscillator according to claim 2, wherein the circuit element comprises a temperature-sensing element and a temperature compensation circuit that compensates for the frequency temperature characteristics of the oscillation signal based on a signal from the temperature-sensing element.

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