Oscillator

Abstract

To provide an oscillator capable of suppressing a short circuit between a vibration element and a circuit element.SOLUTION: The oscillator includes a package including an accommodation space, a resonator element disposed in the accommodation space and bonded to the package via a first bonding member, and a circuit element disposed in the accommodation space and flip-chip mounted on the package via a second bonding member. A circuit element including an oscillation circuit, and a third bonding member bonding the vibration element and the circuit element, in which the circuit element is located between the vibration element and the second bonding member, and the vibration element has a plate shape having a first surface located on the circuit element side and a second surface in a front-back relationship with the first surface, there are provided a vibrator substrate having a thin part, and a thick part thicker than the thin part, and protruding toward a circuit element with respect to the thin part, a first excitation electrode disposed on a first surface of the thin part, and a second excitation electrode disposed on a second surface of the thin part, wherein the thick part is bonded to the circuit element via a third bonding member.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 recessed portion. The crystal oscillator further includes a piezoelectric diaphragm bonded to the bottom surface of the first recessed portion and an integrated circuit element bonded to the bottom surface of the second recessed portion. The integrated circuit element is bonded to the bottom surface of the second recessed portion using face-down bonding technology, with its wiring surface facing the bottom surface of the second recessed portion. The piezoelectric diaphragm is bonded at its base end to the bottom surface of the first recessed portion using a conductive resin adhesive and at its tip end to the back surface of the integrated circuit element using 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] However, in the crystal oscillator of Patent Document 1, when the piezoelectric diaphragm and the integrated circuit element are joined, the silicone resin adhesive that joins them is crushed and spreads, which may come into contact with the electrodes of the piezoelectric diaphragm and adversely affect the vibration characteristics. [Means for solving the problem]

[0005] The oscillator of the present invention comprises: a package having an accommodating space; a vibration element disposed in the accommodation space and joined to the package via a first joining member; a circuit element that is disposed in the accommodating space, is flip-chip mounted to the package via a second bonding member, and includes an oscillation circuit that oscillates the vibration element to generate an oscillation signal; a third bonding member bonding the vibration element and the circuit element together, the circuit element is located between the vibration element and the second bonding member, the vibration element has a plate-like vibration substrate having a first surface located on the circuit element side and a second surface opposite to the first surface, the vibration substrate having a thin portion and a thick portion that is thicker than the thin portion and protrudes toward the circuit element side relative to the thin portion; a first excitation electrode disposed on the first surface of the thin portion; and a second excitation electrode disposed on the second surface of the thin portion and facing the first excitation electrode via the thin portion; The thick portion is joined to the circuit element via the third joining member. [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. 2 is a perspective view of the vibration element as seen from above. [Figure 3] FIG. 2 is a perspective view of the vibration element as seen from below. [Figure 4] FIG. 10 is a perspective view of a modified example of the vibrator as viewed from below. [Figure 5] FIG. 2 is a top view showing the bonding state of the vibration element. [Figure 6] FIG. 6 is a cross-sectional view taken along line AA in FIG. 5. [Figure 7] FIG. 6 is a cross-sectional view taken along line BB in FIG. 5. [Figure 8] FIG. 10 is a cross-sectional view of an oscillator according to a second embodiment. [Figure 9] FIG. 11 is a perspective view of a vibration element included in an oscillator according to a third embodiment, as viewed from below. [Figure 10] FIG. 2 is a cross-sectional view of an oscillator. [Figure 11] FIG. 2 is a cross-sectional view of an oscillator. [Figure 12] 10 is a top view showing a bonding state of a vibration element included in an oscillator according to a fourth embodiment. FIG. [Figure 13] 13 is a cross-sectional view taken along line CC in FIG. 12. [Figure 14] FIG. 11 is a perspective view of a vibration element included in an oscillator according to a fifth embodiment, viewed from below. [Figure 15] FIG. 2 is a top view showing the bonding state of the vibration element. [Figure 16] FIG. 16 is a cross-sectional view taken along the line DD in FIG. [Figure 17] FIG. 13 is a perspective view of a vibration element included in an oscillator according to a sixth embodiment, viewed from below. [Figure 18] FIG. 2 is a cross-sectional view of an oscillator. 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 perspective view of a vibration element seen from above. FIG. 3 is a perspective view of the vibration element seen from below. FIG. 4 is a perspective view of a modified example of the vibrator seen from below. FIG. 5 is a top view showing the bonding state of the vibration element. FIG. 6 is a cross-sectional view taken along line AA in FIG. 5. FIG. 7 is a cross-sectional view taken along line BB in FIG. 5.

[0009] For ease of explanation, each of Figures 1 to 7 illustrates an X-axis, a Y-axis, and a Z-axis that are orthogonal to one another. For ease of explanation, the direction along the X-axis will also be 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 will also be referred to as the "plus side," and the opposite side as the "negative side." The arrowed side of the Z-axis, which is the thickness direction of oscillator 1, will also be 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 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, i.e., on the positive side in the Z-axis direction. In other words, the circuit element 6 is disposed between the second bonding member B2 and the vibration element 5. In addition, 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 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 arranged 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 a 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] The vibration element 5 is an AT-cut quartz crystal vibration element. AT-cut quartz crystal vibration elements have third-order frequency-temperature characteristics, resulting in excellent frequency stability. As shown in FIGS. 2 and 3, the vibration element 5 is cut out of quartz crystal by AT-cutting, and includes a plate-shaped vibration substrate 51 having 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.

[0021] The vibration substrate 51 is a rectangle with its longitudinal direction in the X-axis direction in plan view from the Z-axis direction. Therefore, hereinafter, the end (one end) of the vibration substrate 51 on the negative side in the X-axis direction is also referred to as the base end, and the end (the other end) on the positive side in the X-axis direction is also referred to as the tip end.

[0022] The vibrating substrate 51 has a so-called "inverted mesa" structure in which the vibrating region Q is recessed from the surroundings, and has a recess 510 formed on the lower surface 51a. The portion that overlaps the recess 510 and has a small thickness is a thin portion 511, and the portion that is located around the recess 510, does not overlap the recess 510, and is thicker than the thin portion 511 is a thick portion 512.

[0023] Furthermore, the thick portion 512 protrudes downward relative to the thin portion 511, that is, toward the circuit element 6. In other words, the lower surface 51a of the thick portion 512 is located closer to the circuit element 6 than the lower surface 51a of the thin portion 511. Furthermore, the thick portion 512 is located around the thin portion 511 and is formed along the edge of the vibration substrate 51. Specifically, the thick portion 512 is U-shaped and arranged to surround three sides of the thin portion 511 excluding the base end side, that is, both sides in the Y-axis direction and the positive side in the X-axis direction.

[0024] In the following, the portion of the thick portion 512 that is located at the tip of the vibration substrate 51 (the positive side of the thin portion 511 in the X-axis direction) and extends along the Y-axis direction will also be referred to as the "first portion 512a," the portion that is located at the end of the vibration substrate 51 on the positive side of the Y-axis direction (the positive side of the thin portion 511 in the Y-axis direction), extends along the X-axis direction, and whose end on the positive side of the X-axis direction is connected to one end of the first portion 512a will also be referred to as the "second portion 512b," and the portion that is located at the end of the vibration substrate 51 on the negative side of the Y-axis direction (the negative side of the thin portion 511 in the Y-axis direction), extends along the X-axis direction, and whose end on the positive side of the X-axis direction is connected to the other end of the first portion 512a will also be referred to as the "third portion 512c."

[0025] The electrodes also include a first excitation electrode 521 disposed on the lower surface 51a of the thin portion 511, and a second excitation electrode 531 disposed on the upper surface 51b of the thin portion 511 and facing the first excitation electrode 521 across the thin portion 511. The portion of the thin portion 511 sandwiched between the first and second excitation electrodes 521, 531 forms a vibration region Q. By surrounding the vibration region Q with the thick portion 512, vibration can be effectively confined to the vibration region Q, and vibration leakage from the vibration element 5 can be effectively suppressed. This suppresses a decrease in the Q value of the vibration element 5, resulting in improved oscillation characteristics of the vibration element 5.

[0026] The electrode is located on the lower surface 51a of the vibration substrate 51 and has a first connection terminal 522 and a second connection terminal 532 arranged side by side in the Y-axis direction at a base end thereof. Of these, the first connection terminal 522 is arranged at one end of the thick portion 512, i.e., at the base end (the end on the negative side in the X-axis direction) of the third portion 512c. Meanwhile, the second connection terminal 532 is arranged at the other end of the thick portion 512, i.e., at the base end (the end on the negative side in the X-axis direction) of the second portion 512b. The electrode further has 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.

[0027] However, the configuration of the vibration element 5 is not particularly limited. For example, as shown in FIG. 4, the thick portion 512 may be configured to be arranged only on the tip side of the thin portion 511, that is, may be configured to be composed of only the first portion 512a. Furthermore, as in an embodiment described later, the thick portion 512 may be in the shape of a frame surrounding the entire periphery of the thin portion 511. Furthermore, for example, the shape of the vibration substrate 51 in plan view 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.

[0028] 5 and 6, the vibration element 5 has a base end joined to the bottom surface of the first recess 311 via two conductive first bonding members B1. The first connection terminal 522 is electrically connected to one of the internal terminals 321 via one first bonding member B1, and the second connection terminal 532 is electrically connected to the other internal terminal 321 via one first bonding member B1. This electrically connects the vibration element 5 and the circuit element 6 via the base substrate 3.

[0029] 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. This provides the first bonding member B1 with sufficiently high thermal conductivity. Furthermore, compared to when a metal bump or the like is used, the first bonding member B1 is softer 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.

[0030] Here, the first bonding member B1, which is a conductive resin adhesive, spreads when applied and is crushed when bonded. Therefore, for example, if the first bonding member B1 for electrically connecting the first connection terminal 522 and one of the internal terminals 321 comes into contact with the second connection terminal 532 or the other internal terminal 321, or conversely, if the first bonding member B1 for electrically connecting the second connection terminal 532 and the other internal terminal 321 comes into contact with the first connection terminal 522 or one of the internal terminals 321, a short circuit occurs, causing the oscillator 1 to function unstable or unable to perform its desired function. Therefore, in this embodiment, the first connection terminal 522 is disposed on the third portion 512c of the thick portion 512, the second connection terminal 532 is disposed on the second portion 512b of the thick portion 512, and the thin portion 511 is interposed between them, thereby suppressing the spreading of the first bonding members B1 and making the above-mentioned problem less likely to occur.

[0031] Furthermore, by using a conductive resin adhesive for the first bonding members B1, the diameter of the first bonding members B1 becomes larger than when, for example, the first bonding members B1 are made of metal bumps. For example, the diameter of the first bonding members B1 when a conductive resin adhesive is used is approximately 200 μm, and the diameter of the first bonding members B1 when metal bumps are used is approximately 50 μm. Therefore, by using a conductive resin adhesive for the first bonding members B1, heat from the base substrate 3 is more easily transferred to the vibration element 5 via the first bonding members B1.

[0032] 5 and 7, the oscillator 1 further includes a conductive third bonding member B3 located between the vibration element 5 and the circuit element 6, bonding the tip of the vibration element 5 to the upper surface of the circuit element 6. With this configuration, the vibration element 5 is supported at both ends by the first and third bonding members B1 and B3, stabilizing the posture of the vibration element 5. This effectively suppresses fluctuations in the oscillation characteristics of the vibration element 5, stabilizing the oscillation characteristics of the oscillator 1.

[0033] Furthermore, by joining the vibration element 5 and the circuit element 6 with the third bonding member B3, the vibration element 5 and the circuit element 6 are thermally connected via the third bonding member B3. This reduces the temperature difference between the vibration element 5 and the circuit element 6, particularly the temperature difference between the vibration element 5 and the temperature sensing element 61. As a result, the error between the actual temperature of the vibration element 5 and the compensation temperature (the temperature detected by the temperature sensing element 61) used in the temperature compensation circuit 63 is reduced, thereby improving the temperature compensation accuracy. This results in a highly accurate oscillator 1.

[0034] The third bonding member B3 is electrically conductive and therefore has sufficiently high thermal conductivity. This reduces the temperature difference between the vibration element 5 and the temperature-sensing element 61, improving temperature compensation accuracy. In particular, in this embodiment, the third bonding member B3 is a conductive resin-based adhesive. Similar to the first bonding member B1, the third bonding member B3 is an epoxy-based conductive adhesive made of epoxy resin with a metal filler, such as Ag (silver) filler, dispersed therein. By using a conductive resin-based adhesive as the third bonding member B3, the same effects as the first bonding member B1 can be achieved. That is, as a first effect, the third bonding member B3 becomes soft, effectively absorbing and alleviating stress generated between the vibration element 5 and the circuit element 6. Furthermore, as a second effect, the diameter of the third bonding member B3 is easily increased, allowing for more efficient heat transfer between the vibration element 5 and the circuit element 6. This reduces the temperature difference between the vibration element 5 and the temperature-sensing element 61, improving temperature compensation accuracy. However, the configuration of the third bonding member B3 is not particularly limited. The third joint member B3 may be insulating.

[0035] More specifically, the third bonding member B3 bonds the lower surface 51a of the first portion 512a of the thick portion 512 located at the tip of the vibration element 5 to the upper surface of the circuit element 6. By bonding the third bonding member B3 to the lower surface 51a of the thick portion 512 of the vibration element 5 in this manner, the third bonding member B3 is effectively prevented from spreading toward the lower surface 51a of the thin portion 511, and contact between the third bonding member B3 and the first excitation electrode 521 disposed on the lower surface 51a of the thin portion 511 can be effectively prevented. This effectively prevents adverse effects on the vibration characteristics of the vibration element 5. Furthermore, it effectively prevents unintended short circuits between the rear surface 6b, which is the ground surface of the circuit element 6, and the vibration element 5.

[0036] The above has described the oscillator 1. As described above, such oscillator 1 includes the package 2 having an accommodation space S, the vibration element 5 disposed in the accommodation space S and bonded to the package 2 via a first bonding member B1, the circuit element 6 disposed in the accommodation space S and flip-chip mounted to the package 2 via a second bonding member B2, and including an oscillation circuit 62 that causes the vibration element 5 to oscillate and generate an oscillation signal, and the third bonding member B3 bonding the vibration element 5 and the circuit element 6. In addition, the circuit element 6 is located between the vibration element 5 and the second bonding member B2. The vibration element 5 has a plate-like shape including a lower surface 51a, which is a first surface located on the circuit element 6 side, and an upper surface 51b, which is a second surface opposite to the lower surface 51a. The vibration element 5 includes a vibration substrate 51 having a thin portion 511 and a thick portion 512 that is thicker than the thin portion 511 and protrudes toward the circuit element 6 relative to the thin portion 511. The vibration substrate 51 also includes a first excitation electrode 521 disposed on the lower surface 51a of the thin portion 511, and a second excitation electrode 531 disposed on the upper surface 51b of the thin portion 511 and facing the first excitation electrode 521 via the thin portion 511. The thick portion 512 is bonded to the circuit element 6 via a third bonding member B3. This configuration effectively prevents contact between the third bonding member B3 and the first excitation electrode 521. This effectively prevents adverse effects on the vibration characteristics of the vibration element 5.

[0037] As described above, the vibration element 5 is disposed at the base end, which is one end of the vibration substrate 51, and includes the first connection terminal 522 electrically connected to the first excitation electrode 521 and the second connection terminal 532 electrically connected to the second excitation electrode 531. The thick portion 512 is disposed at least at the tip end, which is the other end of the vibration substrate 51 located opposite the base end. The first connection terminal 522 and the second connection terminal 532 are each bonded to the package 2 via a first bonding member B1, and the thick portion 512 located at the tip end is bonded to the circuit element 6 via a 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, stabilizing the posture of the vibration element 5. This effectively suppresses fluctuations in the oscillation characteristics of the vibration element 5, stabilizing the oscillation characteristics of the oscillator 1.

[0038] As described above, the thick portion 512 has a first portion 512a located on the tip side of the thin portion 511 and joined to the circuit element 6 via the third bonding member B3, a second portion 512b located on one side in the Y-axis direction, which is perpendicular to the X-axis direction in which the base end and tip end of the thin portion 511 are aligned, and in which the second connection terminal 532 is located, and a third portion 512c located on the other side of the thin portion 511 in the Y-axis direction and in which the first connection terminal 522 is located, and thus surrounds three sides of the thin portion 511. The thin portion 511 is located between the first connection terminal 522 and the second connection terminal 532. This configuration effectively prevents short circuits caused by contact between the two first bonding members B1.

[0039] Second Embodiment 8 is a cross-sectional view of the oscillator according to the second embodiment. The cross section of FIG. 8 corresponds to the cross section of FIG.

[0040] 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.

[0041] 8, the circuit element 6 of this embodiment has an insulating film 68 arranged on the rear surface 6b and a first electrode pad 67 arranged on the insulating film 68. By arranging the first electrode pad 67 on the insulating film 68 in this manner, it is possible to easily insulate the first electrode pad 67 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.

[0042] Furthermore, the first electrode pad 67 overlaps the thick portion 512 located at the tip of the vibration element 5 in a plan view from the Z-axis direction. The first electrode pad 67 also overlaps the temperature sensing element 61 in a plan view from the Z-axis direction. The circuit element 6 also has a first via 66 that penetrates the wiring surface 6a and the back surface 6b and thermally connects the first electrode pad 67 and the temperature sensing element 61. Although not shown, an insulating film is formed between the first via 66 and the semiconductor substrate 60 to insulate them from each other.

[0043] The first electrode pads 67 and the first 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 first electrode pads 67 and the first 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 first electrode pads 67 and the first vias 66 having high thermal conductivity. However, the constituent materials of the first electrode pads 67 and the first vias 66 are not particularly limited. Furthermore, since the first electrode pads 67 and the first vias 66 are not used for electrical connection, they may be made of an insulating material.

[0044] In this circuit element 6, the third bonding member B3 is bonded to the first electrode pad 67. This thermally connects the vibration element 5 and the temperature sensitive element 61 via the third bonding member B3, the first electrode pad 67, and the first via 66. This reduces the temperature difference between the vibration element 5 and the temperature sensitive element 61, allowing temperature compensation by the temperature compensation circuit 63 to be performed more accurately. In particular, in this embodiment, the tip of the vibration element 5, the first electrode pad 67, the first via 66, and the temperature sensitive element 61 overlap one another in a plan view from the Z-axis direction. This effectively minimizes the thermal path between the vibration element 5 and the temperature sensitive element 61, further reducing the temperature difference between the vibration element 5 and the temperature sensitive element 61.

[0045] As described above, in the oscillator 1 of this embodiment, the circuit element 6 includes a semiconductor substrate 60 having a wiring surface 6a located on the second bonding member B2 side and a back surface 6b opposite the wiring surface 6a and located on the vibration element 5 side; a first electrode pad 67 located on the back surface 6b side of the semiconductor substrate 60 and bonded to the thick portion 512 via the third bonding member B3; a first via 66 formed in the semiconductor substrate 60 and penetrating the wiring surface 6a and the back surface 6b; an oscillation circuit 62 located on the wiring surface 6a side of the semiconductor substrate 60; a temperature sensing element 61; 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. The temperature sensing element 61 and the first electrode pad 67 are connected via the first via 66. This configuration reduces the temperature difference between the vibration element 5 and the temperature sensing element 61, allowing for more accurate temperature compensation by the temperature compensation circuit 63.

[0046] The second embodiment can also achieve the same effects as the first embodiment described above.

[0047] <Third embodiment> Fig. 9 is a perspective view of the vibration element of the oscillator according to the third embodiment, seen from below. Fig. 10 and Fig. 11 are cross-sectional views of the oscillator. The cross section of Fig. 10 corresponds to the cross section of Fig. 6, and the cross section of Fig. 11 corresponds to the cross section of Fig. 7.

[0048] 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 vibration element 5. 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 each drawing of this embodiment, the same reference numerals are used to designate the same components as those in the above-described embodiment.

[0049] As shown in FIG. 9 , in the vibration element 5 of this embodiment, the thick portion 512 has a frame shape that surrounds the entire periphery of the thin portion 511. That is, in addition to the first portion 512a, the second portion 512b, and the third portion 512c, the thick portion 512 further includes a fourth portion 512d that is located on the base end side (the negative side in the X-axis direction) of the thin portion 511, extends along the Y-axis, and connects the negative end portions of the second and third portions 512b and 512c in the X-axis direction. The vibration element 5 also includes a U-shaped conductor pattern 55 that is located on the lower surface 51a of the thick portion 512 and that extends along the second portion 512b, the first portion 512a, and the third portion 512c. That is, the conductor pattern 55 is located around the first excitation electrode 521 and is arranged to surround it on three sides. The first and second connection terminals 522 and 532 are disposed in the fourth portion 512d so as not to come into contact with the conductive pattern 55.

[0050] As shown in FIG. 10 , the base end of the vibration element 5 is bonded to the bottom surface of the first recess 311 via four conductive first bonding members B1. The first connection terminal 522 is electrically connected to one of the internal terminals 321 via one first bonding member B1, and the second connection terminal 532 is electrically connected to the other internal terminal 321 via one first bonding member B1. This electrically connects the vibration element 5 and the circuit element 6 via the base substrate 3. Furthermore, the remaining two first bonding members B1 connect both ends of the conductor pattern 55 to the bottom surface of the first recess 311. This thermally connects the conductor pattern 55 to the base substrate 3 via the two first bonding members B1, and heat from the base substrate 3 is efficiently transferred to the vibration element 5 via the conductor pattern 55.

[0051] 11, the third bonding member B3 is bonded to the conductive pattern 55 disposed on the lower surface 51a of the first portion 512a of the thick portion 512. As described above, in the oscillator 1, the conductive pattern 55 is bonded to the first bonding member B1 and the third bonding member B3. Therefore, heat from the base substrate 3 is efficiently transferred to the vibration element 5 via the first bonding member B1, and further, the heat is efficiently transferred to the circuit element 6 via the third bonding member B3. This reduces the temperature difference between the vibration element 5 and the circuit element 6, particularly the temperature difference between the vibration element 5 and the temperature sensing element 61. As a result, the error between the actual temperature of the vibration element 5 and the compensation temperature (the temperature detected by the temperature sensing element 61) used in the temperature compensation circuit 63 is reduced, thereby improving the temperature compensation accuracy. This results in a highly accurate oscillator 1.

[0052] In the oscillator 1 described above, the vibration element 5 has a conductor pattern 55 located around the first excitation electrode 521 and disposed on the lower surface 51a of the thick portion 512. The conductor pattern 55 is then bonded to the first bonding member B1 and the third bonding member B3. This configuration reduces the temperature difference between the vibration element 5 and the temperature sensing element 61, improving the temperature compensation accuracy. This results in a highly accurate oscillator 1.

[0053] The third embodiment can also achieve the same effects as the first embodiment described above.

[0054] <Fourth embodiment> Fig. 12 is a top view showing a bonding state of the vibration element included in the oscillator according to the fourth embodiment, and Fig. 13 is a cross-sectional view taken along line CC in Fig. 12 .

[0055] The oscillator 1 according to this embodiment is similar to the oscillator 1 according to the first embodiment described above, except that the orientation of the vibration element 5 is different. 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 each drawing of this embodiment, the same reference numerals are used to designate the same components as those in the above-described embodiment.

[0056] As shown in FIG. 12 , in the oscillator 1 of this embodiment, the vibration element 5 is rotated 180° around the Z axis relative to the first embodiment described above, i.e., the tip end faces the negative side in the X-axis direction and the base end faces the positive side in the X-axis direction. In a plan view from the Z-axis direction, the base end of the vibration element 5 overlaps with the circuit element 6, and the tip end overlaps with the bottom surface of the first recess 311. The tip end of the vibration element 5 is bonded to the bottom surface of the first recess 311 via a first bonding member B1. In this embodiment, the internal terminal 321 is omitted from the bottom surface of the first recess 311, and the vibration element 5 and the base substrate 3 are not electrically connected. However, this is not limited thereto. For example, in order to increase the bonding strength between the first bonding member B1 and the base substrate 3, a dummy terminal to which the first bonding member B1 is bonded may be disposed on the bottom surface of the first recess 311.

[0057] 13, the circuit element 6 has a pair of second electrode pads 65 arranged on the insulating film 68. By arranging the pair of second electrode pads 65 on the insulating film 68 in this way, each second electrode pad 65 can be easily insulated from the rear surface 6b, which is the ground surface.

[0058] In addition, in a plan view from the Z-axis direction, the pair of second electrode pads 65 overlap the base ends of the vibration elements 5 and are arranged side by side in the Y-axis direction. The circuit element 6 also has a pair of second vias 64 that penetrate the wiring surface 6a and the back surface 6b and electrically connect each second electrode pad 65 to the oscillation circuit 62. Although not shown, an insulating film is formed between the second vias 64 and the semiconductor substrate 60, insulating them from each other. The second electrode pads 65 and the second vias 64, like the first electrode pads 67 and the first vias 66, are made of various metal materials such as gold (Au), copper (Cu), aluminum (Al), etc.

[0059] 13, the vibrating element 5 is bonded at its base end to the upper surface of the circuit element 6 via two conductive third bonding members B3. The first connection terminal 522 is electrically connected to one of the second electrode pads 65 via one of the third bonding members B3, and the second connection terminal 532 is electrically connected to the other of the second electrode pads 65 via the other of the third bonding members B3. This electrically connects the vibrating element 5 and the oscillator circuit 62 via the third bonding member B3. This configuration shortens the electrical path between the vibrating element 5 and the oscillator circuit 62, thereby reducing parasitic capacitance, compared to the configuration in which the vibrating element 5 and the oscillator circuit 62 are electrically connected via the base substrate 3, as in the first embodiment described above. Therefore, the oscillator 1 is suitable for increasing the frequency of the oscillation signal.

[0060] Specifically, the third bonding member B3 bonds the thick portion 512 located at the base end of the vibration element 5, i.e., the bottom surface 51a of the end portions of the second and third portions 512b and 512c on the positive side in the X-axis direction, to the top surface of the circuit element 6. Bonding the third bonding member B3 to the bottom surface 51a of the thick portion 512 of the vibration element 5 effectively prevents the thin portion 511 of the third bonding member B3 from spreading toward the bottom surface 51a. This effectively prevents, for example, a short circuit caused by contact between the third bonding member B3 bonded to the second connection terminal 532 and the first excitation electrode 521. This also effectively prevents fluctuations in vibration characteristics caused by the third bonding member B3 spreading over the vibration region Q. In particular, in this embodiment, the thin portion 511 is disposed between the first connection terminal 522 and the second connection terminal 532, effectively preventing a short circuit caused by contact between the two third bonding members B3.

[0061] In the oscillator 1 described above, as described above, the thick portion 512 is located at least at the base end, which is one end of the vibration substrate 51. The vibration element 5 is disposed on the thick portion 512 located at the base end, and has a first connection terminal 522 electrically connected to the first excitation electrode 521 and a second connection terminal 532 electrically connected to the second excitation electrode 531. The first connection terminal 522 and the second connection terminal 532 are each joined to the circuit element 6 via a third bonding member B3, and the other end, i.e., the tip end, located opposite the base end, is joined to the package 2 via a first bonding member B1. With this configuration, the vibration element 5 is supported at both ends by the first and third bonding members B1 and B3, stabilizing the posture of the vibration element 5. This effectively suppresses fluctuations in the oscillation characteristics of the vibration element 5, stabilizing the oscillation characteristics of the oscillator 1.

[0062] As described above, the thin portion 511 is located between the first connection terminal 522 and the second connection terminal 532. This configuration effectively prevents short circuits caused by contact between the two third joint members B3.

[0063] As described above, the circuit element 6 includes a semiconductor substrate 60 having a wiring surface 6a located on the second bonding member B2 side and a back surface 6b opposite the wiring surface 6a and located on the vibration element 5 side, a second electrode pad 65 located on the back surface 6b side of the semiconductor substrate 60, and a second via 64 formed on the semiconductor substrate 60, penetrating the wiring surface 6a and the back surface 6b, and electrically connecting the second electrode pad 65 to the oscillation circuit 62 located on the wiring surface 6a side. With 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 the configuration in which the vibration element 5 and the oscillation circuit 62 are electrically connected via the base substrate 3, as in the first embodiment described above. Therefore, the oscillator 1 is suitable for increasing the frequency of the oscillation signal.

[0064] The fourth embodiment can also achieve the same effects as the first embodiment.

[0065] Fifth Embodiment Fig. 14 is a perspective view of the vibration element of the oscillator according to the fifth embodiment, seen from below; Fig. 15 is a top view showing the bonding state of the vibration element; and Fig. 16 is a cross-sectional view taken along line DD in Fig. 15.

[0066] The oscillator 1 according to this embodiment is similar to the oscillator 1 according to the fourth embodiment, except for the configurations of 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 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 embodiments.

[0067] 14, similarly to the third embodiment described above, the vibration element 5 of this embodiment has a frame shape in which the thick portion 512 surrounds the entire periphery of the thin portion 511. That is, in addition to the first portion 512a, the second portion 512b, and the third portion 512c, the thick portion 512 further has a fourth portion 512d that is located on the base end side of the thin portion 511, extends along the Y-axis direction, and connects the ends of the second and third portions 512b and 512c on the positive side in the X-axis direction.

[0068] As shown in FIG. 15 , the vibration element 5 is bonded at its base end to the upper surface of the circuit element 6 via three conductive third bonding members B3. As shown in FIG. 16 , the circuit element 6 has an insulating film 68 disposed on the back surface 6b and a first electrode pad 67 disposed on the insulating film 68, similar to the second embodiment described above. The first electrode pad 67 overlaps the thick portion 512 located at the base end of the vibration element 5, i.e., the fourth portion 512d, in a plan view from the Z axis direction. The first electrode pad 67 also overlaps the temperature-sensitive element 61 in a plan view from the Z axis direction. The circuit element 6 also has a first via 66 that penetrates between the wiring surface 6a and the back surface 6b and thermally connects the first electrode pad 67 and the temperature-sensitive element 61.

[0069] The first connection terminal 522 and one of the second electrode pads 65 are electrically connected via one third bonding member B3, and the second connection terminal 532 and the other second electrode pad 65 are electrically connected via one third bonding member B3. This electrically connects the vibration element 5 and the oscillation circuit 62 via the third bonding member B3. Furthermore, the fourth portion 512d of the thick portion 512 and the first electrode pad 67 are bonded via the remaining third bonding member B3. This thermally connects the vibration element 5 and the temperature sensing element 61 via the third bonding member B3, the first electrode pad 67, and the first via 66. This reduces the temperature difference between the vibration element 5 and the temperature sensing element 61, allowing the temperature compensation circuit 63 to perform temperature compensation more accurately.

[0070] The fifth embodiment can also achieve the same effects as the first embodiment.

[0071] Sixth Embodiment Fig. 17 is a perspective view of the vibration element of the oscillator according to the sixth embodiment, as viewed from below. Fig. 18 is a cross-sectional view of the oscillator. The cross section of Fig. 18 corresponds to the cross section of Fig. 16.

[0072] The oscillator 1 according to this embodiment is similar to the oscillator 1 according to the fifth embodiment, except for the configuration of the vibration element 5. 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 embodiments.

[0073] 17, the oscillator 1 of this embodiment has a frame-shaped thick portion 512, similar to the fifth embodiment. The vibration element 5 is disposed on the lower surface 51a of the thick portion 512 and has a U-shaped conductor pattern 55 along the second portion 512b, the first portion 512a, and the third portion 512c. That is, the conductor pattern 55 is positioned around the first excitation electrode 521, surrounding it on three sides except for the base end side. The first and second connection terminals 522 and 532 are disposed in the fourth portion 512d of the thick portion 512 so as not to come into contact with the conductor pattern 55.

[0074] The vibrating element 5 is bonded at its base end to the upper surface of the circuit element 6 via four conductive third bonding members B3. As shown in FIG. 18 , the first connection terminal 522 is electrically connected to one of the second electrode pads 65 via one third bonding member B3, and the second connection terminal 532 is electrically connected to the other second electrode pad 65 via another third bonding member B3. This electrically connects the vibrating element 5 and the oscillation circuit 62 via the third bonding member B3. Furthermore, both ends of the conductor pattern 55 are thermally connected to the circuit element 6 via the remaining two third bonding members B3. In particular, one of these third bonding members B3 is bonded to the first electrode pad 67, thermally connecting the conductor pattern 55 and the temperature sensing element 61. This configuration, similar to the third embodiment described above, reduces the temperature difference between the vibrating element 5 and the temperature sensing element 61, improving temperature compensation accuracy. This results in a highly accurate oscillator 1.

[0075] The sixth embodiment can also achieve the same effects as the first embodiment described above.

[0076] 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]

[0077] 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, 51a...bottom surface, 51b...top surface, 510...recess, 511...thin portion, 512...thick portion, 512a...first portion, 512b...second portion, 512c...third portion, 512d...fourth portion, 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, 55...conductor pattern, 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...second electrode pad, 66...first via, 67...first electrode pad, 68...insulating film, 69...connection terminal, B1...first bonding member, B2...second bonding member, B3...third bonding member, Q...vibration area, S...accommodation space

Claims

1. a package having a storage space; a vibration element disposed in the accommodation space and joined to the package via a first joining member; a circuit element that is disposed in the accommodation space, is flip-chip mounted to the package via a second bonding member, and includes an oscillation circuit that oscillates the vibration element to generate an oscillation signal; a third bonding member bonding the vibration element and the circuit element together, the circuit element is located between the vibration element and the second bonding member, the vibration element has a plate-like vibration substrate having a first surface located on the circuit element side and a second surface opposite to the first surface, the vibration substrate having a thin portion and a thick portion that is thicker than the thin portion and protrudes toward the circuit element side relative to the thin portion; a first excitation electrode disposed on the first surface of the thin portion; and a second excitation electrode disposed on the second surface of the thin portion and facing the first excitation electrode via the thin portion; an oscillator, wherein the thick portion is joined to the circuit element via the third joining member;

2. the vibration element is disposed at one end of the vibration substrate, and has a first connection terminal electrically connected to the first excitation electrode and a second connection terminal electrically connected to the second excitation electrode; the thick portion is disposed at least at the other end portion of the vibration substrate that is located opposite to the one end portion, 2. The oscillator according to claim 1, wherein the first connection terminal and the second connection terminal are each joined to the package via the first joining member, and the thick portion located at the other end is joined to the circuit element via the third joining member.

3. the circuit element includes a semiconductor substrate having a wiring surface located on the second bonding member side and a back surface opposite to the wiring surface and located on the vibration element side; a first electrode pad disposed on the rear surface side of the semiconductor substrate and joined to the thick portion via the third joining member; a first via formed in the semiconductor substrate and penetrating the wiring surface and the back surface; the oscillation circuit disposed on the wiring surface side of the semiconductor substrate, a temperature sensing element, 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, The oscillator according to claim 2 , wherein the temperature sensitive element and the first electrode pad are connected through the first via.

4. the thick portion includes a first portion located on the other end side of the thin portion and joined to the circuit element via the third joining member; a second portion located on one side in a direction perpendicular to a direction in which the one end and the other end of the thin-walled portion are aligned, and in which the second connection terminal is arranged; a third portion located on the other side in a direction perpendicular to the direction in which the one end and the other end of the thin-walled portion are aligned, and in which the first connection terminal is arranged; The shape surrounds the thin-walled portion on three sides, 3. The oscillator according to claim 2, wherein the thin portion is located between the first connection terminal and the second connection terminal.

5. the vibration element is disposed at one end of the vibration substrate, and has a first connection terminal electrically connected to the first excitation electrode and a second connection terminal electrically connected to the second excitation electrode; the thick portion has a first portion located on the other end side opposite to the one end of the thin portion, a second portion located on one side in a direction perpendicular to the direction in which the one end and the other end of the thin portion are aligned and in which the second connection terminal is arranged, and a third portion located on the other side in the direction perpendicular to the direction in which the one end and the other end of the thin portion are aligned and in which the first connection terminal is arranged, and has a shape that surrounds three sides of the thin portion; the thin portion is located between the first connection terminal and the second connection terminal, the first connection terminal and the second connection terminal are respectively joined to the package via the first joining member, and the first portion is joined to the circuit element via the third joining member; the circuit element includes a semiconductor substrate having a wiring surface located on the second bonding member side and a back surface opposite to the wiring surface and located on the vibration element side; a first electrode pad arranged on the back surface side of the semiconductor substrate and joined to the first portion via the third bonding member; a first via formed in the semiconductor substrate and penetrating the wiring surface and the back surface; the oscillation circuit arranged on the wiring surface side of the semiconductor substrate; a temperature sensing element; 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, wherein the temperature sensing element and the first electrode pad are connected via the first via.

6. the thick portion is located at least at one end of the vibration substrate, the vibration element is disposed in the thick portion located at the one end, and has a first connection terminal electrically connected to the first excitation electrode and a second connection terminal electrically connected to the second excitation electrode; 2. The oscillator according to claim 1, wherein the first connection terminal and the second connection terminal are each joined to the circuit element via the third joining member, and the other end located opposite the one end is joined to the package via the first joining member.

7. 7. The oscillator according to claim 6, wherein the thin portion is located between the first connection terminal and the second connection terminal.

8. the circuit element includes a semiconductor substrate having a wiring surface located on the second bonding member side and a back surface opposite to the wiring surface and located on the vibration element side; a second electrode pad disposed on the rear surface side of the semiconductor substrate; 7. The oscillator according to claim 6, further comprising a second via formed on the semiconductor substrate, penetrating the wiring surface and the back surface, and electrically connecting the oscillation circuit arranged on the wiring surface side to the second electrode pad.

9. the vibration element has a conductor pattern located around the first excitation electrode and disposed on the first surface of the thick portion, The oscillator according to claim 1 , wherein the conductor pattern is joined to the first joining member and the third joining member.

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