JP2021057755A - Method for manufacturing vibration device - Google Patents

Abstract

To provide a method for manufacturing a vibration device that can prevent a reduction in reliability of an integrated circuit due to thermal damage.SOLUTION: A method for manufacturing a vibration device includes: a hole forming step of forming, on a semiconductor substrate having a first surface and a second surface in a front-back relation, a hole that opens in the first surface; an insulating film forming step of forming an insulating film on an inner surface of the hole; a through electrode forming step of charging a conductive material in the hole to form a through electrode; an integrated circuit forming step of, after the through electrode forming step, forming an integrated circuit on the first surface of the semiconductor substrate; a vibration piece arrangement step of arranging a vibration piece on the semiconductor substrate; and a lid joining step of joining a lid that covers the vibration piece to the semiconductor substrate.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a vibrating device.

Patent Document 1 describes, as a method of forming an integrated circuit on a silicon substrate, a step of forming a through hole in a silicon wafer in which an integrated circuit is formed on one main surface side, and after forming an insulating layer on the inner wall of the through hole. A method including a step of forming a conductive film and forming a through electrode electrically connected to an integrated circuit is disclosed.

Japanese Unexamined Patent Publication No. 2013-031133

However, in the method of forming the through electrode after forming the integrated circuit as described in Patent Document 1, the integrated circuit is thermally damaged in the step of forming the insulating layer or the conductive film in the through hole. Therefore, the reliability of the integrated circuit may decrease. Further, if these steps are performed at a low temperature in order to reduce thermal damage to the integrated circuit, poor formation of the insulating layer and through silicon via is likely to occur, and the reliability of the integrated circuit may also deteriorate. There is.

The method for manufacturing a vibration device according to this application example includes a hole forming step of forming a hole to be opened in the first surface on a semiconductor substrate having a first surface and a second surface which are in a front-to-back relationship.
An insulating film forming step of forming an insulating film on the inner surface of the hole, and
A through electrode forming step of filling the holes with a conductive material to form a through electrode,
After the through silicon via forming step, an integrated circuit forming step of forming an integrated circuit on the first surface of the semiconductor substrate, and an integrated circuit forming step.
The vibrating piece arranging step of arranging the vibrating piece on the semiconductor substrate and
It is characterized by including a lid joining step of joining a lid covering the vibrating piece to the semiconductor substrate.

In the method for manufacturing a vibration device according to the present application example, in the hole forming step, the hole is not penetrated through the second surface.
After the through electrode forming step, it is preferable to include a substrate thinning step of thinning the semiconductor substrate from the second surface side and penetrating the holes through the second surface.

In the method for manufacturing a vibration device according to this application example, it is preferable that the substrate thinning step is performed after the lid joining step.

The method for manufacturing a vibration device according to this application example preferably includes a terminal forming step of forming a terminal electrically connected to the through electrode on the second surface after the substrate thinning step.

In the method for manufacturing a vibration device according to this application example, the semiconductor substrate is a silicon substrate.
In the insulating film forming step, it is preferable to form the insulating film by thermally oxidizing the silicon substrate.

In the method for manufacturing a vibration device according to this application example, the conductive material is preferably polysilicon.

It is sectional drawing which shows the vibration device which concerns on 1st Embodiment. It is a top view which shows the vibrating piece which the vibrating device of FIG. 1 has. It is a figure which shows the manufacturing process of the vibration device of FIG. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing which shows the structure of the conventional vibration device. It is sectional drawing which shows the vibration device which concerns on 2nd Embodiment. It is a figure which shows the manufacturing process of the vibration device of FIG. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device. It is sectional drawing for demonstrating the manufacturing method of a vibrating device.

Hereinafter, the manufacturing method of the vibration device according to this application example will be described in detail based on the embodiment shown in the attached drawings.

<First Embodiment>
FIG. 1 is a cross-sectional view showing a vibration device according to the first embodiment. FIG. 2 is a plan view showing a vibrating piece included in the vibrating device of FIG. FIG. 3 is a diagram showing a manufacturing process of the vibration device of FIG. 4 to 12 are cross-sectional views for explaining a method of manufacturing a vibration device, respectively. FIG. 13 is a cross-sectional view showing the configuration of a conventional vibration device. For convenience of explanation, the three axes orthogonal to each other are shown as the X-axis, the Y-axis, and the Z-axis in each figure. Further, the side to which the arrow in the Z-axis direction faces is also referred to as "up", and the opposite side is also referred to as "down". Further, the plan view from the Z-axis direction is also simply referred to as "plan view". Further, in the following description, "formed (arranged) on the upper surface" means not only the case of directly forming (arranging) on the upper surface but also the case of forming (arranging) at a position separated from the upper surface by a predetermined distance, that is, "upper surface side". Including the case of "forming (arranging)". The same applies to the lower surface.

Before explaining the manufacturing method of the vibration device 1, first, an example of the vibration device 1 manufactured by this manufacturing method will be briefly described. The vibrating device 1 shown in FIG. 1 includes a base substrate 2, a vibrating piece 3 arranged on the upper surface of the base substrate 2, and a lid 4 covering the vibrating piece 3 and being joined to the upper surface of the base substrate 2. Have.

The base substrate 2 is a silicon substrate. However, the base substrate 2 is not particularly limited, and a semiconductor substrate other than silicon, for example, a semiconductor substrate such as Ge, GaP, GaAs, or InP may be used.

Further, the base substrate 2 has an upper surface 2a as a first surface and a lower surface 2b as a second surface, which are in a front-to-back relationship, and the surface thereof is covered with an insulating film 20. Further, an integrated circuit 5 electrically connected to the vibrating piece 3 is formed on the upper surface 2a of the base substrate 2. The integrated circuit 5 has an element separation region T1 and an activation region T2 surrounded by the element separation region T1, and an active element (not shown) such as a transistor is formed in the activation region T2. By forming the integrated circuit 5 on the base board 2, the space of the base board 2 can be effectively utilized. In particular, by forming the integrated circuit 5 on the upper surface 2a, the integrated circuit 5 can be arranged in the storage space S described later, and the integrated circuit 5 can be protected from the external environment. The integrated circuit 5 is not particularly limited, and examples thereof include an oscillation circuit that oscillates a vibrating piece 3 to generate a frequency of a reference signal such as a clock signal.

Further, on the upper surface 2a of the base substrate 2, a laminated body 50 in which an insulating layer 51, a wiring layer 52, an insulating layer 53, a passage film 54, and a terminal layer 55 are laminated is provided, and via wiring included in the wiring layer 52. A plurality of active elements (not shown) formed on the upper surface 2a are electrically connected to form an integrated circuit 5. The terminal layer 55 is electrically connected to the wiring layer 52, and includes a pair of terminals 551 and 552 for electrically connecting to the vibrating piece 3. For convenience of explanation, the laminated body 50 includes one wiring layer 52, but the present invention is not limited to this, and a plurality of wiring layers 52 may be laminated via the insulating layer 53. That is, the wiring layer 52 and the insulating layer 53 may be alternately laminated a plurality of times between the insulating layer 51 and the passivation film 54.

Further, a plurality of terminals 56 are provided on the lower surface 2b of the base substrate 2. Further, each of these terminals 56 is electrically connected to the integrated circuit 5 via a through electrode 57 that penetrates the base substrate 2 in the thickness direction. Such a terminal 56 functions as an external connection terminal for electrically connecting to an external electronic device such as a circuit board. The plurality of terminals 56 include, for example, a terminal connected to a power supply, a terminal connected to the ground, and a terminal to which an oscillation signal from the integrated circuit 5 is output. However, the number and use of the terminals 56 are not particularly limited, and can be appropriately set according to the configuration of the integrated circuit 5. In each figure, some terminals 56 are not shown.

The lid 4 is a silicon substrate like the base substrate 2. As a result, the linear expansion coefficients of the base substrate 2 and the lid 4 become equal, the generation of thermal stress due to thermal expansion is suppressed, and the vibration device 1 has excellent vibration characteristics. Further, since the vibrating device 1 can be formed by a semiconductor process, the vibrating device 1 can be manufactured with high accuracy and can be miniaturized. However, the lid 4 is not particularly limited, and a semiconductor substrate other than silicon, for example, a semiconductor substrate such as Ge, GaP, GaAs, or InP may be used.

The lid 4 has a bottomed recess 41 that opens on the lower surface thereof and houses the vibrating piece 3 inside. The lid 4 is joined to the upper surface 2a of the base substrate 2 via the joining member 6 on the lower surface thereof. As a result, a storage space S for accommodating the vibrating piece 3 is formed between the lid 4 and the base substrate 2. The storage space S is airtight and is in a decompressed state, preferably a state closer to vacuum. As a result, the oscillation characteristics of the vibrating piece 3 are improved. However, the atmosphere of the storage space S is not particularly limited, and may be, for example, an atmosphere in which an inert gas such as nitrogen or Ar is sealed, and may be in an atmospheric pressure state or a pressurized state instead of a reduced pressure state. Good.

As shown in FIG. 2, the vibrating piece 3 has a vibrating substrate 31 and an electrode arranged on the surface of the vibrating substrate 31. The vibrating substrate 31 has a thickness sliding vibration mode, and is formed of an AT-cut quartz substrate in this embodiment. Since the AT-cut crystal substrate has a third-order frequency temperature characteristic, it becomes a vibrating piece 3 having an excellent temperature characteristic. Further, the electrodes include an excitation electrode 321 arranged on the upper surface of the vibration substrate 31 and an excitation electrode 322 arranged on the lower surface so as to face the excitation electrode 321. Further, the electrodes electrically connect the pair of terminals 323 and 324 arranged on the lower surface of the vibrating substrate 31, the wiring 325 that electrically connects the terminals 323 and the excitation electrode 321 and the terminals 324 and the excitation electrode 322. It has a wiring 326 and a connection.

The configuration of the vibrating piece 3 is not limited to the above configuration. For example, the vibrating piece 3 may have a mesa type in which the vibrating region sandwiched between the excitation electrodes 321 and 322 protrudes from the surroundings, or conversely, the vibrating piece 3 has a reverse mesa type in which the vibrating region is recessed from the surroundings. It may be. Further, bevel processing for grinding the periphery of the vibrating substrate 31 and convex processing for making the upper surface and the lower surface convex curved surfaces may be performed.

Further, the vibrating piece 3 is not limited to one that vibrates in the thickness sliding vibration mode, and may be, for example, a vibrating piece in which a plurality of vibrating arms bend and vibrate in the in-plane direction. That is, the vibrating substrate 31 is not limited to the one formed from the AT-cut crystal substrate, and the crystal substrate other than the AT-cut crystal substrate, for example, an X-cut crystal substrate, a Y-cut crystal substrate, a Z-cut crystal substrate, and a BT-cut crystal. It may be formed of a substrate, an SC-cut quartz substrate, an ST-cut quartz substrate, or the like. Further, in the present embodiment, the vibrating substrate 31 is composed of quartz, but is not limited to this, for example, lithium niobate, lithium tantalate, lithium tetraborate, langalite, potassium niobate, gallium phosphate. It may be composed of a piezoelectric single crystal such as, or may be composed of a piezoelectric single crystal other than these. Furthermore, the vibration piece 3 is not limited to the piezoelectric drive type vibration piece, and may be an electrostatic drive type vibration piece using electrostatic force.

Such a vibrating piece 3 is fixed to the upper surface 2a of the base substrate 2, more specifically, to the upper surface of the laminated body 50 by the conductive joining members B1 and B2 via the joining members B1 and B2. Further, the joining member B1 electrically connects the terminal 551 of the laminated body 50 and the terminal 323 of the vibrating piece 3, and the joining member B2 is the terminal 552 of the laminated body 50 and the terminal 324 of the vibrating piece 3. And are electrically connected. As a result, the vibrating piece 3 and the integrated circuit 5 are electrically connected.

The joining members B1 and B2 are not particularly limited as long as they have both conductivity and bondability, and are, for example, various metal bumps such as gold bumps, silver bumps, copper bumps, and solder bumps, polyimide-based, epoxy-based, and the like. A conductive adhesive or the like in which a conductive filler such as a silver filler is dispersed in various silicone-based or acrylic-based adhesives can be used. When the former metal bumps are used as the joining members B1 and B2, the generation of gas from the joining members B1 and B2 can be suppressed, and the environmental change of the storage space S, particularly the increase in pressure can be effectively suppressed. On the other hand, when the latter conductive adhesive is used as the joining members B1 and B2, the joining members B1 and B2 become softer than the metal bumps, and stress is less likely to be transmitted to the vibrating piece 3.

The configuration of the vibration device 1 has been briefly described above. Next, the manufacturing method of the vibration device 1 will be specifically described with reference to FIGS. 3 to 12. As shown in FIG. 3, the method for manufacturing the vibrating device 1 includes a hole forming step S11 for forming a hole 21 to be opened in the upper surface 2a of the base substrate 2 and an insulating film forming step for forming an insulating film 20 on the inner surface of the hole 21. S12, a through electrode forming step S13 in which a conductive material is filled in the hole 21 to form a through electrode 57, an integrated circuit forming step S14 in which an integrated circuit 5 is formed on the upper surface 2a, and a vibrating piece 3 on the upper surface 2a. On the vibrating piece arranging step S15 to be arranged, the lid joining step S16 for joining the lid 4 covering the vibrating piece 3 to the base substrate 2, the substrate thinning step S17 for thinning the base substrate 2, and the lower surface 2b of the base substrate 2. The terminal forming step S18 for forming the terminal 56 and the individualizing step S19 are included. Hereinafter, each of these steps S11 to S18 will be described in detail in order. The dotted line in FIGS. 4 to 11 indicates a portion to be cut or removed by the time the vibration device 1 is completed.

<Hole forming step S11>
As shown in FIG. 4, a base substrate 2 included in a silicon wafer is prepared, and a hole 21 that opens in the upper surface 2a of the base substrate 2 is formed in the base substrate 2. The base substrate 2 prepared here is thicker than the thickness of the base substrate 2 in the finished product shown in FIG. As a result, the strength of the base substrate 2 is increased, and the handling is improved. Further, the hole 21 is formed of a bottomed recess that is deeper than the thickness of the base substrate 2 in the finished product shown in FIG. 1, and does not penetrate to the lower surface 2b of the base substrate 2. By making the hole 21 a bottomed recess, the formation time of the hole 21 is shortened as compared with the case where the hole 21 is penetrated through the lower surface 2b, for example. Further, in the through electrode forming step S13, it becomes easy to fill the hole 21 with the conductive material, and it becomes easy to form the through electrode 57. The method for forming the holes 21 is not particularly limited, but the holes 21 can be formed by, for example, dry etching, in particular, a Bosch process. As a result, the holes 21 having a high aspect ratio can be formed, and the vibration device 1 can be miniaturized. Not limited to this, in this step, the hole 21 may be penetrated through the lower surface 2b.

<Insulating film forming step S12>
As shown in FIG. 5, the base substrate 2 is thermally oxidized to form an insulating film 20 made of _{silicon oxide (SiO 2} ) on the surface of the base substrate 2, particularly on the inner surface of the holes 21. By forming the insulating film 20 by thermal oxidation, a dense and homogeneous insulating film 20 can be formed on the surface of the base substrate 2. Further, the difference in linear expansion coefficient between the insulating film 20 and the base substrate 2 can be reduced. Therefore, the vibration device 1 is less likely to generate thermal stress and has excellent oscillation characteristics. However, the constituent material of the insulating film 20 is not particularly limited, and may be made of, for example, silicon nitride (SiN). The method for forming the insulating film 20 is not limited to thermal oxidation, and may be formed by, for example, CVD (Chemical Vapor Deposition).

<Through Silicon Via Forming Step S13>
As shown in FIG. 6, the hole 21 is filled with a conductive material, and a through electrode 57 that penetrates the base substrate 2 is formed at the time of completion, although it is non-penetrating in this state. The conductive material is not particularly limited, but in this embodiment, conductive polysilicon is used. Conductive polysilicon refers to polysilicon that has been imparted with conductivity by doping impurities such as phosphorus (P), boron (B), and arsenic (As), for example. By using polysilicon as the conductive material in this way, the through electrode 57 has sufficient resistance to the heat applied in the subsequent integrated circuit forming step S14. Therefore, electrical defects caused by the through silicon via 57 are less likely to occur. Further, the difference in coefficient of linear expansion from the base substrate 2 can be reduced. Therefore, the vibration device 1 is less likely to generate thermal stress and has excellent oscillation characteristics. However, the conductive material is not particularly limited, and for example, a metal material having excellent heat resistance such as tungsten (W) can be used.

<Integrated circuit forming step S14>
As shown in FIG. 7, an element separation region T1 and an activation region T2 surrounded by the element separation region T1 are formed on the upper surface 2a side of the base substrate 2, and an active region (not shown) such as a transistor is formed in the activation region T2. Form at least one element. The position of the through electrode 57 is designed so as not to overlap with the element separation region T1, in other words, to overlap with the activation region T2. Next, the insulating layer 51, the wiring layer 52, the insulating layer 53, the passivation film 54, and the terminal layer 55 are laminated in this order on the upper surface 2a of the base substrate 2 to form the laminated body 50. The laminate 50 is formed except for the joint portion of the upper surface 2a of the base substrate 2 with the lid 4. As described above, the integrated circuit 5 is formed.

By forming the integrated circuit 5 after forming the through electrode 57 in this way, it is possible to reduce the thermal damage (heat history) that the integrated circuit 5 receives during manufacturing. Specifically, in the method of forming the through electrode 57 after forming the integrated circuit 5, heat from forming the insulating film 20 and the through electrode 57 is applied to the integrated circuit 5, but in the method of the present embodiment, the heat is applied to the integrated circuit 5. At least, the heat for forming the insulating film 20 and the through silicon via 57 is not applied to the integrated circuit 5. Therefore, it is possible to suppress a decrease in reliability of the integrated circuit 5. Further, by forming the through electrode 57 before forming the integrated circuit 5, the insulating film 20 and the through electrode 57 can be formed under an appropriate temperature without considering the thermal damage of the integrated circuit 5. Therefore, the insulating film 20 and the through silicon via 57 are less likely to be poorly formed.

Each layer of the laminated body 50 can be formed by, for example, film formation by CVD and patterning by etching. In this embodiment, the insulating layers 51 and 53 are made of silicon oxide (SiO ₂ ), the wiring layer 52 and the terminal layer 55 are made of conductive polysilicon, and the passivation film 54 is made of silicon nitride (SiN). Has been done. By forming each layer from a silicon-based material in this way, the difference in linear expansion coefficient between the laminate 50 and the base substrate 2 can be reduced. Therefore, the vibration device 1 is less likely to generate thermal stress and has excellent oscillation characteristics. However, the constituent material of each layer is not particularly limited.

<Vibration piece arrangement step S15>
As shown in FIG. 8, a vibrating piece 3 is prepared, and the vibrating piece 3 is joined to the upper surface 2a of the base substrate 2, specifically, the upper surface of the laminated body 50 via the joining members B1 and B2. Further, as a result, the terminal 551 of the laminated body 50 and the terminal 323 of the vibrating piece 3 are electrically connected via the joining member B1, and the terminal 552 of the laminated body 50 and the terminal of the vibrating piece 3 are electrically connected via the joining member B2. It is electrically connected to 324. As a result, the vibrating piece 3 and the integrated circuit 5 are electrically connected.

<Lid joining step S16>
As shown in FIG. 9, the lid 4 contained in the silicon wafer is prepared and bonded to the upper surface 2a of the base substrate 2 via the bonding member 6 in a reduced pressure environment. The lid 4 prepared here is made thicker than the lid 4 in the finished product shown in FIG. 1, and the lid 4 is made after the terminal forming step S18 and before the individualizing step S19. May be thinned from the upper surface side thereof. As a result, the strength of the lid 4 being manufactured is increased, and the handling is improved.

<Substrate thinning step S17>
As shown in FIG. 10, the base substrate 2 is thinned from the lower surface 2b side thereof, that is, unnecessary portions are removed, and the non-penetrating through electrode 57 is penetrated through the lower surface 2b of the base substrate 2. The thinning method is not particularly limited, and for example, cutting, grinding, polishing, etching, or the like can be used. Further, as a method of grinding and polishing, for example, back grind, CMP (chemical mechanical polishing), dry polishing and the like can be used in combination.

<Terminal forming step S18>
As shown in FIG. 11, after the insulating film 20 is formed on the lower surface 2b of the base substrate 2, the terminal 56 is formed at a position overlapping the through electrode 57. As a result, the through electrode 57 and the terminal 56 are electrically connected. As described above, the plurality of vibration devices 1 are integrally formed on the silicon wafer.

<Individualization step S19>
As shown in FIG. 12, it is cut with a dicing saw or the like, and each vibrating device 1 is cut out and separated into individual pieces. From the above, the vibration device 1 is obtained.

The manufacturing method of the vibration device 1 has been described above. As described above, such a method for manufacturing the vibrating device 1 opens an opening in the upper surface 2a of the base substrate 2 as a semiconductor substrate having an upper surface 2a as a first surface and a lower surface 2b as a second surface, which are in a front-to-back relationship. The hole forming step S11 for forming the hole 21 to be formed, the insulating film forming step S12 for forming the insulating film 20 on the inner surface of the hole 21, and the through electrode forming for forming the through electrode 57 by filling the hole 21 with a conductive material. After the step S13 and the through electrode forming step S13, the integrated circuit forming step S14 for forming the integrated circuit 5 on the upper surface 2a of the base substrate 2, the vibrating piece arranging step S15 for arranging the vibrating piece 3 on the base substrate 2, and the vibration. The lid joining step S16 for joining the lid 4 as a lid covering the piece 3 to the base substrate 2 is included.

In such a manufacturing method, since the through electrode 57 is formed and then the integrated circuit 5 is formed, for example, as compared with the conventional method of forming the integrated circuit 5 and then forming the through electrode 57, It is possible to reduce the heat damage (heat history) that the integrated circuit 5 receives during manufacturing. Therefore, the decrease in reliability of the integrated circuit 5 can be effectively suppressed. Further, by forming the through electrode 57 before forming the integrated circuit 5, the insulating film 20 and the through electrode 57 are formed at an appropriate temperature without considering the influence of heat damage on the integrated circuit 5. be able to. Therefore, the insulating film 20 and the through silicon via 57 are less likely to be poorly formed.

Further, for example, in the method of forming the through electrode 57 after forming the integrated circuit 5, as shown in FIG. 13, the through electrode connecting pad 521 used for connecting to the through electrode 47 is provided in the wiring layer 52. Further, in consideration of the misalignment of the through electrode 57, it is necessary to form the through electrode connecting pad 521 to be large to some extent. Therefore, the size of the vibration device 1 is increased by that amount. On the other hand, according to the method of forming the integrated circuit 5 after forming the through electrode 57 as in the present embodiment, the integrated circuit 5 can be formed with excellent position accuracy with respect to the through electrode 57. However, the through electrode connecting pad 521 becomes unnecessary. Therefore, the size of the vibration device 1 can be reduced accordingly.

Further, as described above, in the hole forming step S11, the hole 21 is not penetrated through the lower surface 2b. Further, the method for manufacturing the vibration device 1 includes a substrate thinning step S17 in which the base substrate 2 is thinned from the lower surface 2b side and the holes 21 are penetrated through the lower surface 2b after the through electrode forming step S13. By not penetrating the hole 21 through the lower surface 2b in this way, the formation time of the hole 21 is shortened as compared with the case where the hole 21 is penetrated through the lower surface 2b. Further, by including the substrate thinning step S17, the strength of the base substrate 2 in the previous steps is increased. Therefore, the base substrate 2 is less likely to be damaged in the steps prior to the substrate thinning step S17, and the handling during manufacturing is improved. However, the present invention is not limited to this, and the substrate thinning step S17 may be omitted. In this case, in the hole forming step S11, the hole 21 may be formed by penetrating the lower surface 2b.

Further, as described above, in the method for manufacturing the vibration device 1, the substrate thinning step S17 is performed after the lid joining step S16. As a result, more steps can be completed before the base substrate 2 is thinned. Therefore, the base substrate 2 is less likely to be damaged during manufacturing, and handling during manufacturing is improved. However, the process order of the substrate thinning step S17 is not limited to this.

Further, as described above, the method for manufacturing the vibration device 1 includes a terminal forming step S18 for forming a terminal 56 electrically connected to the through electrode 57 on the lower surface 2b after the substrate thinning step S17. The terminal 56 functions as an external connection terminal used for connecting to an external electronic device. Therefore, by forming such a terminal 56, electrical connection with an external electronic device becomes easy. However, the terminal forming step S18 may be omitted.

Further, as described above, the base substrate 2 is a silicon substrate. Further, in the insulating film forming step S12, the insulating film 20 is formed by thermally oxidizing the base substrate 2. By forming the insulating film 20 by thermal oxidation, a dense and homogeneous insulating film 20 can be formed on the surface of the base substrate 2. Further, the difference in the coefficient of linear expansion between the insulating film 20 and the base substrate 2 can be reduced. Therefore, the vibration device 1 is less likely to generate thermal stress and has excellent oscillation characteristics.

Further, as described above, the conductive material that is a constituent material of the through electrode 57 is conductive polysilicon. By using polysilicon as the conductive material in this way, the through electrode 57 has sufficient resistance to the heat applied in the integrated circuit forming step S14. Therefore, electrical defects caused by the through silicon via 57 are less likely to occur. Further, the difference in the coefficient of linear expansion from the base substrate 2 can be reduced. Therefore, the vibration device 1 is less likely to generate thermal stress and has excellent oscillation characteristics.

<Second Embodiment>
FIG. 14 is a cross-sectional view showing a vibration device according to the second embodiment. FIG. 15 is a diagram showing a manufacturing process of the vibration device of FIG. 16 to 24 are cross-sectional views for explaining a method of manufacturing a vibration device, respectively.

The method for manufacturing the vibration device of the present embodiment is the same as the method for manufacturing the vibration device of the first embodiment described above, except that the position of the integrated circuit 5 is different. In the following description, the method of manufacturing the vibration device of the second embodiment will be mainly described with respect to the differences from the first embodiment described above, and the description of the same matters will be omitted. Further, in FIGS. 14 to 23, the same reference numerals are given to the same configurations as those in the above-described embodiment.

First, an example of the vibration device 1 manufactured by the method for manufacturing the vibration device of the present embodiment will be briefly described. In the vibration device 1 shown in FIG. 14, an integrated circuit 5 is formed on the lower surface 2b of the base substrate 2, and a pair of terminals 56 are formed on the upper surface 2a. By forming the integrated circuit 5 on the lower surface 2b in this way, for example, as compared with the case where the integrated circuit 5 is formed on the upper surface 2a as in the first embodiment described above, the lower surface 2b is joined to the lid 4. Since there is no region, the space for forming the integrated circuit 5 becomes large. In the case of the present embodiment, the terminal layer 55 of the integrated circuit 5 functions as an external connection terminal for electrically connecting to an external electronic component, and the pair of terminals 56 are electrically connected to the vibrating piece 3. It functions as a terminal for making a proper connection. In this embodiment, contrary to the first embodiment described above, the lower surface 2b of the base substrate 2 is the "first surface" and the upper surface 2a is the "second surface".

The configuration of the vibration device 1 has been briefly described above. Next, the manufacturing method of the vibration device 1 will be specifically described. As shown in FIG. 15, the method for manufacturing the vibrating device 1 includes a hole forming step S21 for forming a hole 21 to open in the lower surface 2b of the base substrate 2 and an insulating film forming step for forming an insulating film 20 on the inner surface of the hole 21. S22, a through electrode forming step S23 in which a conductive material is filled in the hole 21 to form a through electrode 57, an integrated circuit forming step S24 in which an integrated circuit 5 is formed on the lower surface 2b, and a base substrate 2 are thinned. Based on the substrate thinning step S25, the terminal forming step S26 for forming the terminal 56 on the upper surface 2a of the base substrate 2, the vibrating piece arranging step S27 for arranging the vibrating piece 3 on the upper surface 2a, and the lid 4 covering the vibrating piece 3. The lid joining step S28 for joining to the substrate 2 and the individualizing step S29 are included. Since the contents of the steps S21 to S29 are the same as those of the steps S11 to S19 of the first embodiment described above, the steps S21 to S29 will be briefly described below.

<Hole forming step S21>
As shown in FIG. 16, the base substrate 2 is prepared, and a hole 21 that opens in the lower surface 2b of the base substrate 2 is formed in the base substrate 2.

<Insulating film forming step S22>
As shown in FIG. 17, the base substrate 2 is thermally oxidized to form an insulating film 20 made of _{silicon oxide (SiO 2} ) on the surface of the base substrate 2, particularly on the inner surface of the holes 21.

<Through Silicon Via Forming Step S23>
As shown in FIG. 18, the hole 21 is filled with a conductive material to form a non-penetrating through electrode 57.

<Integrated circuit forming step S24>
As shown in FIG. 19, the integrated circuit 5 is formed on the lower surface 2b of the base substrate 2.

<Substrate thinning step S25>
As shown in FIG. 20, the base substrate 2 is thinned from the upper surface 2a side thereof, and the non-penetrating through electrode 57 is penetrated through the upper surface 2a of the base substrate 2.

<Terminal forming step S26>
As shown in FIG. 21, after the insulating film 20 is formed on the upper surface 2a of the base substrate 2, the terminal 56 is formed at a position overlapping the through electrode 57.

<Vibration piece arrangement process S27>
As shown in FIG. 22, a vibrating piece 3 is prepared, and the vibrating piece 3 is joined to the upper surface 2a of the base substrate 2 via the joining members B1 and B2. Further, the terminal 561 and the terminal 323 of the vibrating piece 3 are electrically connected via the joining member B1, and the terminal 562 and the terminal 324 of the vibrating piece 3 are electrically connected via the joining member B2.

<Lid joining step S28>
As shown in FIG. 23, the lid 4 is prepared and joined to the upper surface 2a of the base substrate 2 via the joining member 6 in a reduced pressure environment.

<Individualization step S29>
As shown in FIG. 24, each vibrating device 1 is separated by a dicing saw or the like. From the above, the vibration device 1 is obtained.

The manufacturing method of the vibration device 1 has been described above. As described above, such a method for manufacturing the vibration device 1 opens to the lower surface 2b of the base substrate 2 as a semiconductor substrate having the lower surface 2b as the first surface and the upper surface 2a as the second surface, which are in a front-to-back relationship. A hole forming step S21 for forming a hole 21, an insulating film forming step S22 for forming an insulating film 20 on the inner surface of the hole 21, and a through electrode forming step S22 for filling the hole 21 with a conductive material to form a through electrode 57. S23, an integrated circuit forming step S24 for forming an integrated circuit 5 on the lower surface 2b, a vibrating piece arranging step S27 for arranging the vibrating piece 3 on the upper surface 2a, and a lid 4 as a lid for covering the vibrating piece 3 on the base substrate 2. The lid joining step S28 for joining is included.

In such a manufacturing method, since the through electrode 57 is formed and then the integrated circuit 5 is formed, for example, as compared with the conventional method of forming the integrated circuit 5 and then forming the through electrode 57, It is possible to reduce the heat damage (heat history) that the integrated circuit 5 receives during manufacturing. Therefore, the decrease in reliability of the integrated circuit 5 can be effectively suppressed. Further, by forming the through electrode 57 before forming the integrated circuit 5, the insulating film 20 and the through electrode 57 are formed at an appropriate temperature without considering the influence of heat damage on the integrated circuit 5. be able to. Therefore, the insulating film 20 and the through silicon via 57 are less likely to be poorly formed. Further, the vibration device 1 can be miniaturized.

The second embodiment as described above can also exert the same effect as the first embodiment described above.

Although the manufacturing method of the vibration device of this application example has been described above based on the illustrated embodiment, the present application example is not limited to this, and the configuration of each part is an arbitrary configuration having the same function. Can be replaced with one. Further, any other constituents may be added to the present application example. In addition, this application example may be a combination of any two or more configurations of each of the above-described embodiments.

1 ... Vibration device, 2 ... Base substrate, 2a ... Top surface, 2b ... Bottom surface, 20 ... Insulation film, 21 ... Hole, 3 ... Vibration piece, 31 ... Vibration substrate, 321, 322 ... Excitation electrode, 323, 324 ... Terminal, 325, 326 ... Wiring, 4 ... Lid, 41 ... Recess, 47 ... Through electrode, 5 ... Integrated circuit, 50 ... Laminate, 51 ... Insulation layer, 52 ... Wiring layer, 521 ... Through electrode connection pad, 53 ... Insulation Layer, 54 ... Passion film, 55 ... Terminal layer, 551, 552 ... Terminal, 56, 561, 562 ... Terminal, 57 ... Through electrode, 6 ... Joining member, B1, B2 ... Joining member, S ... Storage space, S11 ... Hole forming step, S12 ... Insulating film forming step, S13 ... Through electrode forming step, S14 ... Integrated circuit forming step, S15 ... Vibration piece placement step, S16 ... Cover joining step, S17 ... Substrate thinning step, S18 ... Terminal forming step , S19 ... Individualization step, S21 ... Hole forming step, S22 ... Insulating film forming step, S23 ... Through electrode forming step, S24 ... Integrated circuit forming step, S25 ... Substrate thinning step, S26 ... Terminal forming step, S27 ... Vibration piece placement step, S28 ... lid joining step, S29 ... individualization step, T1 ... element separation region, T2 ... activation region

Claims (6)

A hole forming step of forming a hole to be opened in the first surface on a semiconductor substrate having a first surface and a second surface which are in a front-to-back relationship,
An insulating film forming step of forming an insulating film on the inner surface of the hole, and
A through electrode forming step of filling the holes with a conductive material to form a through electrode,
After the through silicon via forming step, an integrated circuit forming step of forming an integrated circuit on the first surface of the semiconductor substrate, and an integrated circuit forming step.
The vibrating piece arranging step of arranging the vibrating piece on the semiconductor substrate and
A method for manufacturing a vibrating device, which comprises a lid joining step of joining a lid covering the vibrating piece to the semiconductor substrate. In the hole forming step, the hole is not penetrated through the second surface.
The method for manufacturing a vibration device according to claim 1, further comprising a substrate thinning step of thinning the semiconductor substrate from the second surface side and penetrating the holes through the second surface after the through electrode forming step. The method for manufacturing a vibration device according to claim 2, wherein the substrate thinning step is performed after the lid joining step. The method for manufacturing a vibration device according to claim 2 or 3, further comprising a terminal forming step of forming a terminal electrically connected to the through electrode on the second surface after the substrate thinning step. The semiconductor substrate is a silicon substrate, and the semiconductor substrate is a silicon substrate.
The method for manufacturing a vibration device according to any one of claims 1 to 4, wherein in the insulating film forming step, the insulating film is formed by thermally oxidizing the silicon substrate. The method for manufacturing a vibration device according to claim 5, wherein the conductive material is conductive polysilicon.

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