Semiconductor device, temperature compensation method for semiconductor device, and inspection method for semiconductor device

Abstract

This semiconductor device is provided with: a substrate; a resonance generation layer that is disposed on the substrate and that includes a resonance element for which a specific resonance frequency has been set; a temperature sensor layer that is disposed on the substrate and that includes a temperature sensor for detecting an ambient temperature in which the temperature of the resonance generation layer is reflected; and a heater layer that is disposed on the substrate and that includes a heater that maintains the ambient temperature within a constant temperature range.

Description

Semiconductor device, temperature compensation method for semiconductor device, and inspection method for semiconductor device

[0001] The present disclosure relates to a semiconductor device, a temperature compensation method for a semiconductor device, and a method for inspecting a semiconductor device.

[0002] In semiconductor devices such as acoustic wave filters and resonators that include electromechanical resonant elements, the resonant frequency specific to the electromechanical resonant element is determined by its mechanical structure, vibration transmission structure, and the like.

[0003] JP 2022-51000 A

[0004] [Summary] A problem occurs in that the semiconductor device cannot achieve the desired resonant frequency characteristics due to the influence of external temperature and heat generation during operation of the semiconductor device (hereinafter referred to as "self-heating"), etc. An object of the present disclosure is to provide a semiconductor device that has an electromechanical resonant element and can suppress fluctuations in the resonant frequency characteristics due to the influence of external temperature and self-heating.

[0005] To solve the above-mentioned problems, one aspect of the present disclosure provides a semiconductor device including a substrate, a vibration generating layer disposed on the substrate and including a resonant element having a specific resonant frequency, a temperature sensor layer disposed on the substrate, and a heater layer disposed on the substrate. The temperature sensor layer includes a temperature sensor for detecting an ambient temperature that reflects the temperature of the vibration generating layer. The heater layer includes a heater for maintaining the ambient temperature within a certain temperature range.

[0006] Another aspect of the present disclosure is a temperature compensation method for a semiconductor device, including detecting an ambient temperature that reflects the temperature of a vibration generating layer using a temperature sensor formed in a temperature sensor layer disposed on a substrate, and maintaining the ambient temperature within a certain temperature range using a heater formed in a heater layer disposed on the substrate.

[0007] Yet another aspect of the present disclosure is a method for inspecting a semiconductor device, which includes a temperature compensation method for a semiconductor device that detects an ambient temperature that reflects the temperature of a vibration generating layer using a temperature sensor formed in a temperature sensor layer arranged on a substrate, and maintains the ambient temperature within a certain temperature range using a heater formed in a heater layer arranged on the substrate, and inspects characteristics including a resonant frequency within a certain temperature range.

[0008] FIG. 1 is a schematic cross-sectional view illustrating the configuration of a semiconductor device according to the first embodiment. FIG. 2 is a schematic plan view illustrating the configuration of a vibration generating layer of the semiconductor device according to the first embodiment. FIG. 3 is a diagram illustrating an operation flow of the semiconductor device according to the first embodiment. FIG. 4A is a plan view illustrating the configuration of the semiconductor device according to the first embodiment. FIG. 4B is a cross-sectional view taken along the IV-IV direction of FIG. 4A. FIG. 5 is a cross-sectional view illustrating a process of a method for manufacturing a semiconductor device according to the first embodiment (part 1). FIG. 6 is a cross-sectional view illustrating a process of a method for manufacturing a semiconductor device according to the first embodiment (part 2). FIG. 7 is a cross-sectional view illustrating a process of a method for manufacturing a semiconductor device according to the first embodiment (part 3). FIG. 8 is a cross-sectional view illustrating a process of a method for manufacturing a semiconductor device according to the first embodiment (part 4). FIG. 9 is a cross-sectional view illustrating a process of a method for manufacturing a semiconductor device according to the first embodiment (part 5). FIG. 10 is a cross-sectional view illustrating a process of a method for manufacturing a semiconductor device according to the first embodiment (part 6). FIG. 11 is a cross-sectional view illustrating a process of a method for manufacturing a semiconductor device according to the first embodiment (part 7). FIG. 12 is a schematic plan view illustrating an example of the arrangement of a temperature sensor and a heater in the semiconductor device according to the first embodiment. FIG. 13 is a schematic cross-sectional view showing a configuration of a semiconductor device according to a first modification of the first embodiment. FIG. 14 is a schematic plan view showing an example of the configuration of a first electrode and a second electrode of a semiconductor device according to a first modification of the first embodiment. FIG. 15 is a schematic cross-sectional view showing a configuration of a semiconductor device according to a second modification of the first embodiment. FIG. 16 is a process cross-sectional view (part 1) for describing a method for manufacturing the semiconductor device shown in FIG. 15. FIG. 17 is a process cross-sectional view (part 2) for describing a method for manufacturing the semiconductor device shown in FIG. 15. FIG. 18 is a process cross-sectional view (part 3) for describing a method for manufacturing the semiconductor device shown in FIG. 15. FIG. 19 is a process cross-sectional view (part 4) for describing a method for manufacturing the semiconductor device shown in FIG. 15. FIG. 20 is a schematic cross-sectional view showing another configuration of a semiconductor device according to a second modification of the first embodiment. FIG. 21 is a schematic cross-sectional view showing a configuration of a semiconductor device according to a third modification of the first embodiment. FIG. 22 is a schematic cross-sectional view showing another configuration of a semiconductor device according to the third modification of the first embodiment.Fig. 23 is a schematic cross-sectional view showing another configuration of a semiconductor device according to a third modification of the first embodiment. Fig. 24 is a schematic view showing the configuration of a semiconductor device according to a fourth modification of the first embodiment. Fig. 25 is a schematic cross-sectional view showing the configuration of a semiconductor device according to the second embodiment. Fig. 26 is a schematic cross-sectional view showing the configuration of a vibration generating layer of the semiconductor device according to the second embodiment. Fig. 27 is a schematic cross-sectional view showing the configuration of a semiconductor device according to a modification of the second embodiment. Fig. 28 is a schematic cross-sectional view showing another configuration of a semiconductor device according to a modification of the second embodiment.

[0009] [Detailed Description] Hereinafter, embodiments will be described with reference to the drawings. Note that the embodiments described below are comprehensive or specific examples. The numerical values, shapes, materials, components, installation positions of the components, and connection forms shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not recited in the independent claims that represent the highest concepts will be described as optional components. Furthermore, the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions. Furthermore, the following embodiments and their modified examples may include similar components, and similar components will be assigned common reference numerals and redundant description will be omitted.

[0010] 1, a semiconductor device 1 according to a first embodiment includes a substrate 10, a vibration generating layer 20 disposed on the substrate 10, a temperature sensor layer 30 disposed on the substrate 10, and a heater layer 40 disposed on the substrate 10. In the semiconductor device 1 shown in FIG. 1, the heater layer 40, the temperature sensor layer 30, and the vibration generating layer 20 are stacked on the substrate 10.

[0011] 1, the main surface of the substrate 10 on which the vibration generating layer 20 is disposed is defined as an XY plane defined by the X and Y directions. The normal direction of the main surface of the substrate 10, which is perpendicular to the XY plane, is defined as the Z direction.

[0012] The vibration generating layer 20 includes an electromechanical resonator element (hereinafter also referred to as a "resonator element") with a specific resonant frequency. The temperature sensor layer 30 includes a temperature sensor 31 that detects the ambient temperature, which reflects the temperature of the vibration generating layer 20. The heater layer 40 includes a heater 41 that maintains the ambient temperature within a certain temperature range. Hereinafter, the configuration including the temperature sensor 31 and the heater 41 will also be referred to as a "constant temperature system 50."

[0013] The vibration generating layer 20 shown in Fig. 1 is an acoustic wave resonator, and has an acoustic wave generating layer 21 including an acoustic wave vibration layer 210 that vibrates due to acoustic waves, as shown in Fig. 2, for example. The acoustic wave generating layer 21 shown in Fig. 2 includes the acoustic wave vibration layer 210, and a first electrode layer 211 and a second electrode layer 212 arranged on either side of the acoustic wave vibration layer 210. The acoustic wave vibration layer 210 is, for example, a piezoelectric thin film. Hereinafter, the first electrode layer 211 and the second electrode layer 212 will be referred to as "electrode layers" unless otherwise specified.

[0014] The vibration generating layer 20 shown in FIG. 2 is a bulk acoustic wave (BAW) type acoustic wave resonator (hereinafter also referred to as a "BAW type resonator") that uses acoustic waves propagating inside the acoustic wave vibration layer 210. In the semiconductor device 1, an electrical signal is applied via the electrode layer to excite acoustic waves in the acoustic wave vibration layer 210. The excited acoustic waves travel back and forth between the electrode layer and the acoustic wave vibration layer 210. In a BAW type resonator, acoustic waves propagate in the thickness direction of the acoustic wave vibration layer 210. The thickness direction is the direction toward the gap between the first electrode layer 211 and the second electrode layer 212.

[0015] When an input signal input to the semiconductor device 1 has a natural resonant frequency (hereinafter also referred to as the "natural resonant frequency") set in the resonant element formed in the vibration generating layer 20, the impedance between the first electrode layer 211 and the second electrode layer 212 decreases. Therefore, the semiconductor device 1 can be used to configure an RF filter that passes only input signals of a specific frequency. For example, of an input signal that includes signals of various frequencies input to the second electrode layer 212, only signals having the natural resonant frequency are output from the electrode layer.

[0016] The vibration generating layer 20 shown in FIG. 2 further includes a vibration reflecting layer 22. The vibration reflecting layer 22 reflects acoustic waves propagating through the acoustic vibration layer 210 at the interface between the vibration reflecting layer 22 and the acoustic wave generating layer 21. This suppresses propagation of acoustic waves from the acoustic wave generating layer 21 to the substrate 10, improving the electromechanical coupling coefficient, which corresponds to the conversion efficiency between electrical energy and mechanical energy. The vibration reflecting layer 22 may be, for example, an acoustic multilayer film having a structure in which high-impedance films 221, through which acoustic waves pass, and low-impedance films 222, through which acoustic waves pass, are alternately stacked. The semiconductor device 1 may be an SMR (Solid Mounted Resonator) type BAW filter including the vibration reflecting layer 22.

[0017] The temperature sensor 31 may be a conductor wiring formed in the temperature sensor layer 30. By using the conductor wiring as the temperature sensor 31, the temperature sensor 31 can be easily formed. For example, a thin film of platinum (Pt) may be used for the temperature sensor 31. The conductor wiring may have two terminals or four terminals. Alternatively, a semiconductor element may be used for the temperature sensor 31. For example, a diode element that utilizes the temperature coefficient of the forward voltage may be used for the temperature sensor 31.

[0018] The heater 41 may be a conductive wiring formed on the heater layer 40. By using the conductive wiring as the heater 41, it is easy to form the heater 41. For example, a thin film of platinum or tantalum (Ta) may be used for the heater 41.

[0019] The semiconductor device 1 further includes a temperature controller 60 that controls the heat generation of the heater 41 in response to the ambient temperature detected by the temperature sensor 31. The temperature controller 60 adjusts the amount of heat generated by the heater 41, for example, by controlling the power supplied to the heater 41.

[0020] FIG. 3 shows the operation flow of the semiconductor device 1.

[0021] 3, the semiconductor device 1 is started up. Next, in step S2, the temperature sensor 31 measures the ambient temperature of the temperature sensor 31, which reflects the temperature of the vibration generating layer 20. The measured ambient temperature data is sent from the temperature sensor 31 to the temperature controller 60.

[0022] In step S3, the temperature controller 60 controls the heater 41 in accordance with the ambient temperature measured by the temperature sensor 31. For example, if the ambient temperature is lower than a predetermined temperature range that has been set in advance, the temperature controller 60 causes the heater 41 to generate heat and raise the ambient temperature up to the predetermined temperature range.

[0023] In step S4, if the operation of the semiconductor device 1 is to be continued, the process returns to step S2, and the measurement of the ambient temperature by the temperature sensor 31 and the control of the ambient temperature by the heater 41 are repeated. As a result, the ambient temperature is maintained within a certain temperature range while the semiconductor device 1 is operating.

[0024] On the other hand, if it is determined in step S4 that the operation of the semiconductor device 1 is not to be continued, the process proceeds to step S5, where the semiconductor device 1 is stopped.

[0025] As described above, in the operation flow of the semiconductor device 1, the temperature sensor 31 formed in the temperature sensor layer 30 disposed on the substrate 10 detects the ambient temperature, which reflects the temperature of the vibration generating layer 20. The heater 41 formed in the heater layer 40 disposed on the substrate 10 then maintains the ambient temperature within a constant temperature range. According to the temperature compensation method described above, during operation of the semiconductor device 1, the constant temperature system 50 including the temperature sensor 31 and heater 41 maintains the temperature of the vibration generating layer 20 within a constant temperature range.

[0026] The temperature controller 60 controls the power supplied to the heater 41 in accordance with the ambient temperature detected by the temperature sensor 31, thereby adjusting the amount of heat generated by the heater 41. The temperature controller 60 may adjust the amount of heat generated by the heater 41, for example, by switching the operation of the heater 41 on and off. Alternatively, the amount of heat generated by the heater 41 may be adjusted by setting the duty ratio of the on / off operation of the heater 41.

[0027] Typically, electromechanical resonant elements such as MEMS (Micro Electro Mechanical Systems) acoustic wave filters and resonators have a natural resonant frequency determined by their mechanical structure, vibration transmission method, etc. However, due to the temperature outside the semiconductor device (hereinafter referred to as "external temperature") and self-heating during operation, the size, Young's modulus, rigidity modulus, Poisson's ratio, mechanical constants such as internal friction, and the sound speed at which vibration is transmitted fluctuate due to thermal expansion, which causes fluctuations in the target frequency characteristics of the resonant element.

[0028] In contrast, the semiconductor device 1 can be guaranteed to operate at its natural resonant frequency at the temperature set by the constant temperature system 50. In other words, the semiconductor device 1 can maintain its natural resonant frequency without being affected by the external temperature or self-heating. In other words, by setting the ambient temperature using the constant temperature system 50, the electrical and mechanical characteristics of the semiconductor device 1 can be measured at its natural vibration frequency.

[0029] As described above, the semiconductor device 1 can suppress fluctuations in the resonant frequency characteristics due to the influence of external temperature and self-heating. For example, a set ambient temperature and measurement results of the characteristics of the semiconductor device 1 at that ambient temperature are stored in a non-volatile memory or the like. As a result, even if there is an error between the temperature detected by the temperature sensor 31 and the actual external temperature, the electrical and mechanical characteristics of the semiconductor device 1 can be guaranteed by maintaining the set ambient temperature.

[0030] 3, the characteristics of the semiconductor device 1, including the natural resonance frequency, are inspected within a certain temperature range measured by the temperature sensor 31. This makes it possible to inspect the characteristics of the semiconductor device 1 without having to consider the external temperature and measurement error of the temperature sensor 31 during the inspection.

[0031] In the semiconductor device 1, which maintains the ambient temperature using the heater 41, closed-loop control is performed by the constant temperature system 50 to maintain the temperature at a temperature set on the higher side of the temperature range in which the semiconductor device 1 is used. As a result, even if the resonant element of the semiconductor device 1 generates heat due to its own operation, the sum of the heat generated by the resonant element, the heat generated by the heater 41, the influence of the external temperature, and the heat dissipated from the vibration generating layer 20 is balanced. As a result, the semiconductor device 1 operates within the temperature range controlled by the constant temperature system 50. Therefore, the semiconductor device 1 can suppress fluctuations in the resonant frequency characteristics due to the influence of the external temperature.

[0032] When the vibration generating layer 20 itself generates little heat, the temperature of the semiconductor device 1 is significantly affected by the external temperature. Therefore, the temperature set by the constant temperature system 50 may be, for example, the highest anticipated external temperature or near the upper limit of the recommended operating temperature range for the semiconductor device 1. Alternatively, the temperature set by the constant temperature system 50 may be set at the upper limit of the temperature range anticipated for normal use of the semiconductor device 1 to reduce power consumption. Furthermore, considering the error between the temperature detected by the temperature sensor 31 and the external temperature, a temperature correction process may be performed according to previously acquired temperature data when the temperature sensor 31 indicates that the set temperature has been exceeded.

[0033] 1, wiring necessary for the operation of the resonant elements is extended from the vibration generating layer 20. The wiring extended from the electrode layer may be connected to other elements disposed on the substrate 10 to form a circuit, or may be connected to terminals used for inputting and outputting signals to and from the outside of the semiconductor device 1. For example, a radio frequency (RF) filter may be formed using the vibration generating layer 20, which is a BAW resonator.

[0034] For example, as shown in FIGS. 4A and 4B , the semiconductor device 1 has a first wiring 213 electrically connected to the first electrode layer 211 and a second wiring 214 electrically connected to the second electrode layer 212. FIG. 4A is a plan view of the semiconductor device 1 as seen from the Z direction (hereinafter referred to as a "plan view"). FIG. 4B is a cross-sectional view taken along the IV-IV direction in FIG. 4A . Note that, to facilitate understanding of the structure of the semiconductor device 1, the insulating film 215 is omitted from FIG. 4A . The first wiring 213 and the second wiring 214 are, for example, metal wiring. In the semiconductor device 1 shown in FIGS. 4A and 4B , the acoustic wave vibration layer 210 and the second electrode layer 212 are covered with the insulating film 215 in the region above the acoustic wave vibration layer 210 where the wiring is disposed. The first wiring 213 is electrically connected to the first electrode layer 211 via a contact hole penetrating the insulating film 215. The second wiring 214 is electrically connected to the second electrode layer 212 through a contact hole that penetrates the insulating film 215 and the acoustic wave vibration layer 210 in the remaining region excluding the region where the first electrode layer 211 is disposed. Alternatively, the second wiring 214 may be electrically connected to the second electrode layer 212 in the region where the acoustic wave vibration layer 210 is not disposed.

[0035] 4A and 4B, signals are input and output via the first wiring 213 and the second wiring 214. For example, an input signal is input to the first electrode layer 211 via the first wiring 213. Then, a signal of a predetermined frequency is output from the semiconductor device 1 via the second electrode layer 212 and the second wiring 214. The RF filter may be realized by a configuration in which two semiconductor devices 1 are connected in series.

[0036] Alternatively, an RF filter may be configured using a ladder circuit in which multiple semiconductor devices 1 with slightly different natural resonant frequencies are connected in series and in parallel. Bandpass filter characteristics can be obtained by matching the resonant frequency of the series-connected semiconductor devices 1 with the anti-resonant frequency of the parallel-connected semiconductor devices 1.

[0037] In the semiconductor device 1, the ambient temperature set by the constant temperature system 50 may be one type or multiple types. For example, the temperature controller 60 may switch the heat generation amount of the heater 41 so that the ambient temperature becomes one of multiple preset temperatures.

[0038] Hereinafter, a method for manufacturing the semiconductor device 1 according to the first embodiment will be described with reference to the drawings. Note that the method for manufacturing the semiconductor device 1 described below is one example, and it goes without saying that various other manufacturing methods, including variations thereof, can be used.

[0039] 5, the lower part of the heater layer 40 is formed on the upper surface of the substrate 10. The substrate 10 is, for example, a silicon substrate. The heater layer 40 is, for example, a silicon oxide film.

[0040] 6, a heater 41 made of conductive wiring is formed on the upper surface of the partially formed heater layer 40. For example, a Ta film is patterned using photolithography or the like to form the heater 41. Thereafter, as shown in FIG. 7, an upper part of the heater layer 40 is formed so as to cover the heater 41.

[0041] After forming the heater layer 40, the lower part of the temperature sensor layer 30 is formed on the upper surface of the heater layer 40, and then the conductive wiring temperature sensor 31 is formed, as shown in Fig. 8. The temperature sensor layer 30 is, for example, a silicon oxide film. The temperature sensor 31 is formed by patterning a Pt film using, for example, photolithography technology.

[0042] 9, the upper part of the temperature sensor layer 30 is formed so as to cover the temperature sensor 31, and then the vibration reflecting layer 22 is formed on the upper surface of the temperature sensor layer 30. The vibration reflecting layer 22 has a structure in which high-impedance films 221, which have a relatively high acoustic impedance through which elastic waves pass, and low-impedance films 222, which have a relatively low acoustic impedance, are alternately laminated. For example, a tungsten (W) film may be used as the high-impedance film 221, and a silicon oxide film may be used as the low-impedance film 222.

[0043] 10 , after the vibration reflection layer 22 is formed, the second electrode layer 212, the acoustic wave vibration layer 210, and the first electrode layer 211 are formed in this order. The first electrode layer 211 and the second electrode layer 212 may be, for example, a molybdenum (Mo) film. The acoustic wave vibration layer 210 may be, for example, an aluminum nitride (AlN) film.

[0044] Thereafter, an insulating film 215 is formed so as to cover the acoustic wave vibration layer 210 and the first electrode layer 211. As shown in Fig. 11, after forming contact holes that penetrate to the first electrode layer 211 and contact holes that penetrate to the second electrode layer 212, a first wiring 213 that connects to the first electrode layer 211 and a second wiring 214 that connects to the second electrode layer 212 are formed. The first wiring 213 and the second wiring 214 may be, for example, an aluminum film. With the above steps, the semiconductor device 1 is completed.

[0045] 12 shows an example of the arrangement of the temperature sensor 31 and heater 41 as viewed from the normal direction of the upper surface of the substrate 10. The temperature sensor 31 and heater 41 shown in FIG. 12 are conductor wiring. The first sensor electrode 31A and second sensor electrode 31B of the temperature sensor 31 are connected to a temperature controller 60, which calculates the ambient temperature based on the electrical resistance measured by the temperature sensor 31. The first heater electrode 41A and second heater electrode 41B of the heater 41 are connected to the temperature controller 60, which supplies power via the first heater electrode 41A and second heater electrode 41B to cause the heater 41 to generate heat.

[0046] 12 shows an example in which the first sensor electrode 31A and the second sensor electrode 31B, and the first heater electrode 41A and the second heater electrode 41B are drawn from different sides of the outer periphery of the constant temperature system 50 in a plan view. However, the first sensor electrode 31A, the second sensor electrode 31B, the first heater electrode 41A, and the second heater electrode 41B may be drawn from the same side of the constant temperature system 50. Furthermore, the first sensor electrode 31A and the second sensor electrode 31B may be drawn from different sides of the constant temperature system 50, or the first heater electrode 41A and the second heater electrode 41B may be drawn from different sides of the constant temperature system 50. In this way, the arrangement of the first sensor electrode 31A, the second sensor electrode 31B, the first heater electrode 41A, and the second heater electrode 41B can be set arbitrarily.

[0047] The temperature sensor 31 and the heater 41 may be positioned so as to prevent temperature distribution in the vibration generating layer 20. For example, the heater 41 may be positioned so as to overlap the entire surface of the vibration generating layer 20 in a plan view. When the heater layer 40 and the vibration generating layer 20 are stacked as shown in FIG. 1 , the heater 41 may be configured to overlap the entire surface of the vibration generating layer 20, thereby preventing temperature distribution in the XY plane in the vibration generating layer 20.

[0048] 12 exemplarily shows a case where there is one heater 41, multiple heaters 41 may be arranged in the heater layer 40. For example, multiple heaters 41 may be arranged dispersedly in a plan view. By providing multiple heaters 41, even if one of the heaters 41 fails, the other heaters 41 can maintain the ambient temperature within a certain temperature range.

[0049] 13 shows a semiconductor device 1 according to a first modification of the first embodiment, in which the vibration generating layer 20 is formed by stacking a vibration reflecting layer 22, an acoustic wave vibration layer 210, and an electrode formation layer 23. That is, in the semiconductor device 1 shown in FIG. 13, the acoustic wave vibration layer 210 is not sandwiched between electrode layers, and an electrode layer is disposed only on one main surface of the acoustic wave vibration layer 210. For example, a constant temperature system 50 may be combined with a SAW filter that uses surface acoustic waves (SAW).

[0050] When the semiconductor device 1 is a SAW filter, for example, as shown in FIG. 14 , a first electrode 231 and a second electrode 232, each of which is a combination of comb-shaped electrodes, may be formed on the electrode formation layer 23. The first electrode 231 has a configuration in which the comb teeth of a first comb-shaped electrode 231A and the comb teeth of a second comb-shaped electrode 231B are alternately arranged. The second electrode 232 has a configuration in which the comb teeth of a third comb-shaped electrode 232A and the comb teeth of a fourth comb-shaped electrode 232B are alternately arranged. When a signal is input to the first electrode 231, a surface acoustic wave SW is excited by the first comb-shaped electrode 231A and the second comb-shaped electrode 231B. The excited surface acoustic wave SW propagates along the surface of the acoustic wave vibration layer 210 to the third comb-shaped electrode 232A and the fourth comb-shaped electrode 232B, and a signal is output from the second electrode 232.

[0051] 15 shows a semiconductor device 1 according to a second modification of the first embodiment, in which a space 100 is formed between the vibration generating layer 20 and the constant temperature system 50. The space 100 is formed in the temperature sensor layer 30 above the temperature sensor 31.

[0052] 15 , the space 100 is formed, so that the acoustic waves propagating through the acoustic wave vibration layer 210 do not propagate into the substrate 10. Therefore, in the semiconductor device 1 shown in FIG. 15 , the acoustic waves propagating from the acoustic wave vibration layer 210 to the substrate 10 can be suppressed, thereby improving the electromechanical coupling coefficient. In this way, for example, a film bulk acoustic resonator (FBAR) type BAW filter may be combined with a constant temperature system 50.

[0053] A method for manufacturing the semiconductor device 1 according to the second modified example of the first embodiment will be described below with reference to the drawings. Note that the method for manufacturing the semiconductor device 1 described below is just one example, and it goes without saying that various other manufacturing methods, including this modified example, can also be used.

[0054] First, as in the method described with reference to FIGS. 5 to 8 , a heater layer 40 and a temperature sensor layer 30 are formed on the upper surface of the substrate 10 as shown in FIG. 16 . Then, as shown in FIG. 17 , a sacrificial layer 101 is formed on the upper surface of the temperature sensor layer 30. For example, a PSG (Phosphorous Silicate Glass) film is patterned by photolithography or the like to form the sacrificial layer 101. Then, as shown in FIG. 18 , the remaining portion of the temperature sensor layer 30 is formed to cover the side surfaces of the sacrificial layer 101. At this time, the upper surface of the sacrificial layer 101 is exposed on the upper surface of the temperature sensor layer 30.

[0055] 19 , the second electrode layer 212, the acoustic wave vibration layer 210, and the first electrode layer 211 are formed in this order. Then, an insulating film 215 is formed so as to cover the acoustic wave vibration layer 210 and the first electrode layer 211, and then a first wiring 213 connected to the first electrode layer 211 and a second wiring 214 connected to the second electrode layer 212 are formed.

[0056] Thereafter, the sacrificial layer 101 is etched away to form the space 100. To remove the sacrificial layer 101, an etching method using, for example, hydrofluoric acid vapor (HF) can be used. Illustration of the gas path for exposing the sacrificial layer 101 to HF vapor or the like during etching of the sacrificial layer 101 and details of the process will be omitted here. In this way, the semiconductor device 1 shown in FIG. 15 is completed.

[0057] The above describes a method in which the vibration generating layer 20 is formed on the top surface of the constant temperature system 50, and then the space 100 is formed. As another manufacturing method, the constant temperature system 50 and the vibration generating layer 20 may be formed separately, and after the space 100 is formed on the top surface of the constant temperature system 50, the constant temperature system 50 and the vibration generating layer 20 may be bonded together to manufacture the semiconductor device 1.

[0058] 20, a space 100 may be formed between the substrate 10 and the constant temperature system 50. For example, the constant temperature system 50 and the vibration generating layer 20 may be stacked on the substrate 10 having a sacrificial layer 101 formed on its main surface, and the sacrificial layer 101 may be etched away to form the space 100. Alternatively, the semiconductor device 1 shown in FIG. 20 may be manufactured by bonding the stacked structure of the constant temperature system 50 and the vibration generating layer 20 to the substrate 10 having the space 100 formed on its upper surface.

[0059] <Third Modification> At least one of the temperature sensor layer 30 and the heater layer 40 may be disposed at a distance from the vibration generating layer 20 on the upper surface of the substrate 10. In a semiconductor device 1 according to a third modification shown in FIG. 21 , a constant temperature system 50 including a stack of the temperature sensor layer 30 and the heater layer 40 is disposed at a distance from the vibration generating layer 20 on the upper surface of the substrate 10. The semiconductor device 1 shown in FIG. 21 has a configuration in which the temperature sensor layer 30 is disposed midway along the path of heat generated by the heater layer 40 before it reaches the vibration generating layer 20. Even if the constant temperature system 50 is disposed at a distance from the vibration generating layer 20 on the substrate 10, operation at the natural resonant frequency of the semiconductor device 1 at a temperature set by the constant temperature system 50 can be ensured.

[0060] When the vibration generating layer 20 of the semiconductor device 1 is a BAW resonator, heat is generated in the vibration generating layer 20 as a signal propagates through the vibration generating layer 20. In the semiconductor device 1 shown in Figure 21, the substrate 10 functions as part of a heat dissipation path for the heat generated in the vibration generating layer 20. Therefore, the constant temperature system 50 is disposed near the heat dissipation path, and the constant temperature system 50 detects the ambient temperature that reflects the temperature of the vibration generating layer 20.

[0061] 22, the temperature sensor layer 30 and the vibration generating layer 20 may be stacked, and the heater layer 40 may be disposed apart from the vibration generating layer 20. In the semiconductor device 1 shown in FIG. 22, the constant temperature system 50 also detects the ambient temperature, which reflects the temperature of the vibration generating layer 20.

[0062] 23, heat dissipation fins 520 may be arranged on the underside of the substrate 10, facing in the opposite direction to the upper surface of the substrate 10 on which the vibration generating layer 20 is arranged. For example, by joining the substrate 10 and the heat dissipation fins 520 with a bonding material 510 having high thermal conductivity, the heat generated in the vibration generating layer 20 can be efficiently dissipated from the heat dissipation fins 520.

[0063] <Fourth Modification> In the above, a configuration in which the temperature controller 60 is disposed on the substrate 10 has been shown, but the temperature controller 60 may also be disposed outside the semiconductor device 1, as in the semiconductor device 1 according to the fourth modification shown in Fig. 24. For example, as shown in Fig. 24, the temperature controller 60 and the constant temperature system 50 are electrically connected via external terminals 110 of the semiconductor device 1. This makes it possible to ensure that a semiconductor device 1 that does not include a temperature controller 60 operates at the natural resonant frequency of the semiconductor device 1 at a temperature set by the constant temperature system 50.

[0064] For example, a temperature controller 60 may be used that has a function of switching the heat generation amount of the heater 41 so that the ambient temperature becomes one of a plurality of preset temperatures. This allows the heat generation amount of the heater 41 to be switched according to an external instruction. This makes it possible to set optimal characteristics and power consumption for the semiconductor device 1. The temperature controller 60 that has a function of switching the heat generation amount of the heater 41 may be built into the semiconductor device 1.

[0065] 25 , a semiconductor device 1 according to a second embodiment includes a substrate 10, a support portion 11, and a beam-type diaphragm 12 having a fixed portion connected to the support portion 11 and configured to be vibrated in the thickness direction (Z direction). The diaphragm 12 has a cantilever structure and is vibrated in the thickness direction. A vibration generating layer 20 is disposed on the diaphragm 12.

[0066] As shown in FIG. 26 , the vibration generating layer 20 includes a piezoelectric film 230 and a pair of first and second electrode layers 211 and 212 sandwiching the piezoelectric film 230. The semiconductor device 1 may be an actuator in which a diaphragm 12 vibrates when a voltage is applied to the first and second electrode layers 211 and 212. Alternatively, the semiconductor device 1 may be a sensor that detects a voltage generated between the first and second electrode layers 211 and 212 due to vibration of the diaphragm 12. Thus, the semiconductor device 1 of the second embodiment differs from the first embodiment in that the vibration generating layer 20 includes an acoustic wave resonator in that the semiconductor device 1 is a transducer used as an actuator or sensor utilizing the piezoelectricity of the piezoelectric film 230. Other configurations of the semiconductor device 1 of the second embodiment are substantially similar to those of the first embodiment, and therefore, redundant description will be omitted. For example, a temperature controller 60 may be provided externally to the semiconductor device 1.

[0067] <Modification> In the semiconductor device 1 according to the second embodiment, at least one of the temperature sensor layer 30 and the heater layer 40 may be disposed at a distance from the vibration generating layer 20. In the semiconductor device 1 according to the modification shown in Fig. 27, a constant temperature system 50 including the temperature sensor layer 30 and the heater layer 40 stacked together is disposed at a distance from the vibration generating layer 20 on the upper surface of the substrate 10. That is, the vibration generating layer 20 is disposed on the upper surface of the diaphragm 12 having a cantilever structure, and the constant temperature system 50 is disposed on the upper surface of the support portion 11. By disposing the vibration generating layer 20 on the upper surface of the diaphragm 12 and not disposing the constant temperature system 50 on the upper surface of the diaphragm 12, it is possible to prevent the vibration of the diaphragm 12 from being impeded.

[0068] 28 , the vibration generating layer 20 may not include the second electrode layer 212, and a conductive diaphragm 12 may be used instead of the second electrode layer 212. That is, the first electrode layer 211 and the diaphragm 12 may form a pair of electrode layers sandwiching the piezoelectric film 230. For example, a semiconductor layer with a high impurity concentration and thus conductivity may be used for the diaphragm 12.

[0069] Although the embodiments have been described above, the descriptions and drawings that form part of this disclosure should not be understood to limit the embodiments. Various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from this disclosure.

[0070] For example, while the above description has been given of the semiconductor device 1 as a filter and a transducer, the constant temperature system 50 and the vibration generating layer 20 may also be combined with other semiconductor devices 1 having a vibration generating layer 20 including resonant elements with a specific resonant frequency. For example, the semiconductor device 1 may include a resonator used in a resonator, a MEMS mirror, an inertial sensor, a concentration sensor for chemical substances such as gas, or an electromagnetic field sensor for detecting changes in an electromagnetic field. For example, a concentration sensor detects slight variations in resonant frequency due to the adsorption of chemical substances, and an electromagnetic field sensor detects slight variations in resonant frequency due to the influence of an electromagnetic field. Therefore, a semiconductor device that can suppress variations in resonant frequency characteristics due to the influence of external temperature and self-heating is preferably used.

[0071] The above-described embodiment is an example of the present disclosure, and therefore the present disclosure is not limited to the above-described embodiment, and various modifications can be made to the design and other aspects of the present disclosure without departing from the technical concept of the present disclosure.

[0072] [Notes] The technical ideas that can be understood from the present disclosure are described below. Note that, for the purpose of aiding understanding and not intending to be limiting, the components described in the notes are given the reference symbols of the corresponding components in the embodiments. The reference symbols are shown as examples to aid understanding, and the components described in each note should not be limited to the components indicated by the reference symbols.

[0073] (Supplementary Note 1) The semiconductor device 1 includes a substrate 10, a vibration generating layer 20 disposed on the substrate 10, a temperature sensor layer 30 disposed on the substrate 10, and a heater layer 40 disposed on the substrate 10. The vibration generating layer 20 includes a resonant element having a specific resonant frequency. The temperature sensor layer 30 includes a temperature sensor 31 that detects an ambient temperature that reflects the temperature of the vibration generating layer 20. The heater layer 40 includes a heater 41 that maintains the ambient temperature within a constant temperature range. The semiconductor device 1 described in Supplementary Note 1 can provide a semiconductor device that can suppress fluctuations in resonant frequency characteristics due to the effects of external temperature and self-heating.

[0074] (Supplementary Note 2) The semiconductor device 1 described in Supplementary Note 1 further includes a temperature controller 60 that controls heat generation by the heater 41 in response to the ambient temperature detected by the temperature sensor 31. According to the semiconductor device 1 described in Supplementary Note 2, the ambient temperature can be maintained within a certain temperature range by control of the temperature controller 60.

[0075] (Supplementary Note 3) In the semiconductor device 1 described in Supplementary Note 2, the temperature controller 60 controls the power supplied to the heater 41 to adjust the amount of heat generated by the heater 41 .

[0076] (Supplementary Note 4) In the semiconductor device 1 described in Supplementary Note 2 or 3, the temperature controller 60 switches the heat generation amount of the heater 41 so that the ambient temperature becomes one of a plurality of preset temperatures. According to the semiconductor device 1 described in Supplementary Note 4, by switching the heat generation amount of the heater 41, it is possible to set optimal characteristics and power consumption for the semiconductor device 1.

[0077] (Supplementary Note 5) In the semiconductor device 1 described in any one of Supplementary Notes 1 to 4, the heater layer 40, the temperature sensor layer 30, and the vibration generating layer 20 are stacked. According to the semiconductor device 1 described in Supplementary Note 5, the occurrence of temperature distribution in the XY plane in the vibration generating layer 20 can be suppressed.

[0078] (Supplementary Note 6) In the semiconductor device 1 described in any one of Supplementary Notes 1 to 4, at least one of the temperature sensor layer 30 and the heater layer 40 is disposed on the upper surface of the substrate 10 and spaced apart from the vibration generating layer 20. According to the semiconductor device 1 described in Supplementary Note 6, when the substrate 10 functions as part of a heat dissipation path, the constant temperature system 50 can be disposed near the heat dissipation path.

[0079] (Supplementary Note 7) In the semiconductor device 1 according to any one of Supplementary Notes 1 to 6, the temperature sensor 31 is a conductor wiring formed in the temperature sensor layer 30. According to the semiconductor device 1 according to Supplementary Note 7, the temperature sensor 31 can be easily formed.

[0080] (Supplementary Note 8) In the semiconductor device 1 according to any one of Supplementary Notes 1 to 7, the heater 41 is a conductor wiring formed in the heater layer 40. According to the semiconductor device 1 according to Supplementary Note 8, the heater 41 can be easily formed.

[0081] (Supplementary Note 9) In the semiconductor device 1 described in any one of Supplementary Notes 1 to 8, the substrate 10 is part of a heat dissipation path that thermally conducts heat generated in the vibration generating layer 20. According to the semiconductor device 1 described in Supplementary Note 9, the heat generated in the vibration generating layer 20 can be dissipated to the outside via the substrate 10.

[0082] (Supplementary Note 10) In the semiconductor device 1 according to any one of Supplements 1 to 9, the vibration generating layer 20 includes an acoustic wave vibration layer 210 that vibrates due to acoustic waves. According to the semiconductor device 1 according to Supplementary Note 10, fluctuations in the resonant frequency characteristics of the acoustic wave resonator due to the influence of external temperature and self-heating can be suppressed.

[0083] (Supplementary Note 11) In the semiconductor device 1 described in Supplementary Note 10, the acoustic wave vibration layer 210 is a piezoelectric thin film, and the vibration generating layer 20 includes a first electrode layer 211 and a second electrode layer 212 disposed on either side of the acoustic wave vibration layer 210. According to the semiconductor device 1 described in Supplementary Note 11, an acoustic wave propagates in the acoustic wave vibration layer 210 by applying an electric signal to the first electrode layer 211 and the second electrode layer 212.

[0084] (Supplementary Note 12) In the semiconductor device 1 described in Supplementary Note 10 or 11, the vibration generating layer 20 further includes a vibration reflecting layer 22 that reflects elastic waves propagating through the elastic wave vibration layer 210. According to the semiconductor device 1 described in Supplementary Note 12, the elastic waves propagating through the elastic wave vibration layer 210 are reflected at the interface between the vibration reflecting layer 22 and the elastic wave vibration layer 210. Therefore, the elastic waves propagating from the elastic wave vibration layer 210 to the substrate 10 are suppressed, and the electromechanical coupling coefficient can be improved.

[0085] (Appendix 13) In the semiconductor device 1 described in any one of Appendices 1 to 9, the substrate 10 includes a support portion 11 and a beam-shaped diaphragm 12 having a fixed portion connected to the support portion 11 and configured to be vibrable in a thickness direction, and the vibration generating layer 20 is disposed on the diaphragm 12. According to the semiconductor device 1 described in Appendix 13, fluctuations in the resonant frequency characteristics of a transducer having the diaphragm 12 due to the influence of external temperature and self-heating can be suppressed.

[0086] (Appendix 14) In the semiconductor device 1 described in Appendix 13, the vibration generating layer 20 includes a piezoelectric film 230, and a first electrode layer 211 and a second electrode layer 212 arranged on either side of the piezoelectric film 230. According to the semiconductor device 1 described in Appendix 14, fluctuations in the resonant frequency characteristics can be suppressed in a transducer that utilizes the piezoelectricity of the piezoelectric film 230.

[0087] (Supplementary Note 15) A temperature compensation method for a semiconductor device 1 including a substrate 10 on which a vibration generating layer 20 including a resonant element with a specific resonant frequency is disposed, wherein a temperature sensor 31 formed on a temperature sensor layer 30 disposed on the substrate 10 detects an ambient temperature reflecting the temperature of the vibration generating layer 20. The ambient temperature is then maintained within a constant temperature range by a heater 41 formed on a heater layer 40 disposed on the substrate 10. The temperature compensation method described in Supplementary Note 15 can suppress fluctuations in the resonant frequency characteristics of the semiconductor device 1 due to the effects of external temperature and self-heating.

[0088] (Supplementary Note 16) In the temperature compensation method described in Supplementary Note 15, the heat generation amount of the heater is adjusted by controlling the power supplied to the heater 41 in accordance with the ambient temperature detected by the temperature sensor 31. According to the temperature compensation method described in Supplementary Note 16, the ambient temperature can be maintained within a constant temperature range by controlling the power supplied to the heater 41.

[0089] (Supplementary Note 17) A method for inspecting a semiconductor device including the temperature compensation method according to Supplementary Note 15 or 16, wherein characteristics of the semiconductor device including the resonant frequency are inspected within a certain temperature range. According to the method for inspecting a semiconductor device according to Supplementary Note 17, characteristics of the semiconductor device 1 including the natural resonant frequency are inspected within a certain temperature range measured by the temperature sensor 31.

[0090] REFERENCE SIGNS LIST 1 semiconductor device 10 substrate 11 support portion 12 vibration plate 20 vibration generating layer 21 elastic wave generating layer 22 vibration reflecting layer 23 electrode forming layer 30 temperature sensor layer 31 temperature sensor 40 heater layer 41 heater 50 constant temperature system 60 temperature controller 100 space 210 elastic wave vibration layer 211 first electrode layer 212 second electrode layer 230 piezoelectric film

Claims

1. A semiconductor device comprising: a substrate; a vibration generating layer disposed on the substrate and including a resonant element having a specific resonant frequency; a temperature sensor layer disposed on the substrate and including a temperature sensor that detects an ambient temperature that reflects the temperature of the vibration generating layer; and a heater layer disposed on the substrate and including a heater that maintains the ambient temperature within a certain temperature range.

2. The semiconductor device according to claim 1, further comprising a temperature controller that controls heat generation by said heater in response to said ambient temperature detected by said temperature sensor.

3. The semiconductor device according to claim 2, wherein said temperature controller adjusts the amount of heat generated by said heater by controlling the power supplied to said heater.

4. The semiconductor device according to claim 2 or 3, wherein said temperature controller switches the heat generation amount of said heater so that said ambient temperature becomes one of a plurality of preset temperatures.

5. The semiconductor device according to any one of claims 1 to 4, wherein the heater layer, the temperature sensor layer, and the vibration generating layer are stacked.

6. The semiconductor device according to any one of claims 1 to 4, wherein at least one of the temperature sensor layer and the heater layer is disposed on the upper surface of the substrate, spaced apart from the vibration generating layer.

7. The semiconductor device according to any one of claims 1 to 6, wherein the temperature sensor is a conductor wiring formed in the temperature sensor layer.

8. The semiconductor device according to any one of claims 1 to 7, wherein the heater is a conductor wiring formed in the heater layer.

9. The semiconductor device according to any one of claims 1 to 8, wherein the substrate is a part of a heat dissipation path for conducting heat generated in the vibration generating layer.

10. The semiconductor device according to any one of claims 1 to 9, wherein the vibration generating layer includes an elastic wave vibration layer that vibrates in response to elastic waves.

11. The semiconductor device according to claim 10, wherein the acoustic wave vibration layer is a piezoelectric thin film, and the vibration generating layer includes a first electrode layer and a second electrode layer disposed on either side of the acoustic wave vibration layer.

12. The semiconductor device according to claim 10 or 11, wherein the vibration generating layer further includes a vibration reflecting layer that reflects the elastic waves propagated through the elastic wave vibrating layer.

13. A semiconductor device according to any one of claims 1 to 9, wherein the substrate includes a support portion and a beam-type diaphragm having a fixed portion connected to the support portion and configured to be vibrable in a thickness direction, and the vibration generating layer is disposed on the diaphragm.

14. The semiconductor device according to claim 13, wherein the vibration generating layer includes a piezoelectric film and first and second electrode layers disposed on either side of the piezoelectric film.

15. A temperature compensation method for a semiconductor device including a substrate on which a vibration generating layer including a resonant element having a specific resonant frequency is disposed, the method comprising: detecting an ambient temperature that reflects the temperature of the vibration generating layer using a temperature sensor formed in a temperature sensor layer disposed on the substrate; and maintaining the ambient temperature within a certain temperature range using a heater formed in a heater layer disposed on the substrate.

16. The temperature compensation method for a semiconductor device according to claim 15, wherein the amount of heat generated by said heater is adjusted by controlling the power supplied to said heater in accordance with said ambient temperature detected by said temperature sensor.

17. A method for inspecting a semiconductor device, comprising the temperature compensation method according to claim 15 or 16, wherein characteristics of the semiconductor device, including the resonant frequency, are inspected within the given temperature range.

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