Electronic device and method of manufacturing the same

Abstract

The electronic device (1) comprises: an electronic component (10) having a mechanical vibration portion (17); a base substrate (30) on which the electronic component (10) is mounted; an intermediate layer (40) and the base substrate (30) form an internal space (49) for accommodating the electronic component (10), and at least one through hole (46) is formed to open the internal space (49) to the outside; and a sealing layer (50) is arranged on the outside of the intermediate layer (40) and blocks at least one through hole (46) to seal the internal space (49), and an opening portion (39) with a bottom that overlaps with a part of the electronic component (10) is formed on a mounting surface (31A) of the base substrate (30) on which the electronic component (10) is mounted.

Description

Technical Field

[0001] The invention relates to an electronic device and a method for manufacturing the same. Background Art

[0002] As an electronic device having an electronic component having a mechanical vibration part, for example, a piezoelectric vibrator used as a timer device or a load sensor is listed. The piezoelectric vibrator includes a piezoelectric vibration element and a holder that accommodates the piezoelectric vibration element. The piezoelectric vibration element has a mechanical vibration part that converts electrical vibration into mechanical vibration using a piezoelectric effect.

[0003] For example, Patent Document 1 discloses a piezoelectric device including: a piezoelectric vibrating piece having a thin-walled vibrating portion relative to a peripheral portion; an intermediate film formed on the front and back surfaces of the piezoelectric vibrating piece, separated from the vibrating portion and bonded to the peripheral portion; and a sealing film formed on the surface of the intermediate film and laminated on the intermediate film. Thus, according to Patent Document 1, a piezoelectric device can be provided that can be manufactured at a wafer level, thereby achieving low cost and excellent vibration characteristics.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2017-163613

[0005] However, in the piezoelectric device described in Patent Document 1, since the peripheral portion surrounding the vibration portion in a frame shape is in contact with the intermediate film and the sealing film, stress applied from the outside is easily transmitted to the vibration portion, which may cause a problem that frequency fluctuation due to stress increases. Summary of the invention

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic device in which frequency variation due to stress is small and which can be miniaturized, and a method for manufacturing the same.

[0007] An electronic device according to one embodiment of the present invention comprises: an electronic component having a mechanical vibration portion; a base substrate on which the electronic component is mounted; an intermediate layer, which forms an internal space for accommodating the electronic component with the base substrate and has at least one through hole opening the internal space to the outside; and a sealing layer, which is arranged on the outside of the intermediate layer and blocks at least one through hole to seal the internal space, and an opening with a bottom overlapping with a portion of the electronic component is formed on the mounting surface of the base substrate on which the electronic component is mounted.

[0008] A method for manufacturing an electronic device according to one embodiment of the present invention comprises: a substrate preparation step of preparing an aggregate substrate; a sacrificial layer formation step of providing a first sacrificial layer on the aggregate substrate; a mounting step of supporting a portion of an electronic component having a mechanical vibration portion on the first sacrificial layer and mounting the electronic component on the aggregate substrate; a sacrificial layer covering step of covering the electronic component with a second sacrificial layer; an intermediate layer formation step of covering the second sacrificial layer with an intermediate layer, forming at least one through hole in the intermediate layer that opens the second sacrificial layer side toward its opposite side; a space forming step of removing the first sacrificial layer and the second sacrificial layer through at least one through hole to form an internal space between the aggregate substrate and the intermediate layer; and a sealing step of sealing the internal space by blocking at least one through hole with a sealing layer provided on the outside of the intermediate layer.

[0009] According to the present invention, it is possible to provide an electronic device having a small frequency variation due to stress and capable of being miniaturized, and a method for manufacturing the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is an exploded perspective view schematically showing the structure of the crystal oscillator according to the first embodiment.

[0011] Figure 2 It is a plan view schematically showing the structure of the crystal oscillator according to the first embodiment.

[0012] Figure 3 It roughly indicates Figure 2 The structure of the crystal oscillator shown is a cross-sectional view taken along line III-III.

[0013] Figure 4 This is a flow chart schematically showing the method for manufacturing the crystal oscillator according to the first embodiment.

[0014] Figure 5 It is a plan view schematically showing a substrate preparation step of preparing an aggregate substrate.

[0015] Figure 6 This is a cross-sectional view schematically showing a mounting step of mounting a crystal resonator element.

[0016] Figure 7 It is a cross-sectional view schematically showing an intermediate layer forming step of providing an intermediate layer.

[0017] Figure 8 It is a cross-sectional view schematically showing a space forming step of removing the first sacrificial layer and the second sacrificial layer.

[0018] Fig. 9 It is a cross-sectional view schematically showing a sealing step of providing a sealing layer.

[0019] Fig.10 It is a top view schematically showing the separation step of individual chips.

[0020] Fig.11 It is a plan view schematically showing the structure of the crystal oscillator according to the second embodiment.

[0021] Fig.12 It is a plan view schematically showing the structure of a crystal oscillator according to the third embodiment.

[0022] Fig.13 It is a plan view schematically showing the structure of a crystal oscillator according to the fourth embodiment. DETAILED DESCRIPTION

[0023] Below, while referring to the attached Figure 1 The drawings of the embodiments are for illustration only, and the dimensions and shapes of the parts are schematic, and the technical scope of the invention of the present application should not be understood to be limited to the embodiments.

[0024] In the following description, a quartz crystal resonator unit including a quartz crystal resonator is used as an example of a piezoelectric resonator unit. The quartz crystal resonator unit uses a quartz crystal element as a piezoelectric body excited by a piezoelectric effect.

[0025] A crystal oscillator is equivalent to a type of piezoelectric oscillator as an example of an electronic device, a crystal oscillator element is equivalent to a type of piezoelectric oscillator element as an example of an electronic component, and a crystal plate is equivalent to a type of piezoelectric plate. In addition, the vibration (driving) mode of the vibration element of an embodiment of the present invention is not limited to piezoelectric driving. For example, the vibration element of an embodiment of the present invention may be an electrostatically driven type using electrostatic force or a Lorentz driven type using magnetic force, in addition to a piezoelectrically driven vibration element using a piezoelectric substrate. In addition, as long as the electronic component has a mechanical vibration portion that performs mechanical vibration, it is not limited to the above-mentioned vibration element.

[0026] In addition, the piezoelectric sheet of the embodiment of the present invention is not limited to a crystal sheet. The piezoelectric sheet can also be formed of any piezoelectric material such as a piezoelectric single crystal, a piezoelectric ceramic, a piezoelectric film, or a piezoelectric polymer film. As an example, lithium niobate (LiNbO3) can be listed as a piezoelectric single crystal. Similarly, barium titanate (BaTiO3), lead titanate (PbTiO3), lead zirconate titanate (Pb(ZrO3)), and other piezoelectric ceramics can be listed. x Ti 1-x)O3; PZT), aluminum nitride (AlN), lithium niobate (LiNbO3), lithium metaniobate (LiNb2O6), bismuth titanate (Bi4Ti3O 12 ), lithium tantalate (LiTaO3), lithium tetraborate (Li2B4O7), lanthanum silicate (La3Ga5SiO 14 ) or tantalum pentoxide (Ta2O5), etc. Regarding piezoelectric thin films, structures obtained by forming the above-mentioned piezoelectric ceramics on a substrate such as crystal or sapphire by sputtering, etc. can be listed. Regarding piezoelectric polymer films, polylactic acid (PLA), polyvinylidene fluoride (PVDF) or vinylidene fluoride / trifluoroethylene (VDF / TrFE) copolymers, etc. can be listed. The above-mentioned various piezoelectric materials can be used in a stacked manner or in a stacked manner on other components.

[0027] <First Embodiment>

[0028] First, refer to Figure 1 to Figure 3 , while describing the structure of the crystal oscillator 1 according to the first embodiment of the present invention. Figure 1 It is an exploded perspective view schematically showing the structure of the crystal oscillator according to the first embodiment. Figure 2 It is a plan view schematically showing the structure of the crystal oscillator according to the first embodiment. Figure 3 It roughly indicates Figure 2 The cross-sectional view of the structure of the crystal oscillator along the III-III line is shown. Figure 3 It is not a planar cross-sectional view, but a view showing a curved cross-sectional view including the first cast electrode 35a, the first base wiring 34a, the first electrode pad 33a, the first conductive retaining component 36a, the first connecting electrode 16a, the first lead electrode 15a, the first excitation electrode 14a and the fourth cast electrode 35d described later.

[0029] In each of the drawings, in order to make the relationship between the drawings clear and to help understand the positional relationship of each component, an orthogonal coordinate system consisting of an X-axis, a Y'axis, and a Z'axis is sometimes added for convenience. The X-axis, the Y'axis, and the Z'axis correspond to each other in each of the drawings. The X-axis, the Y'axis, and the Z'axis correspond to the crystal axes (Crystallographic Axes) of the crystal plate 11 described later, respectively, the X-axis corresponds to the electrical axis (polar axis), the Y-axis corresponds to the mechanical axis, and the Z-axis corresponds to the optical axis. The Y'axis and the Z'axis are axes obtained by rotating the Y-axis and the Z-axis around the X-axis from the Y-axis to the Z-axis by 35 degrees 15 minutes ± 1 minute 30 seconds. In the following description, the direction parallel to the X-axis is referred to as the "X-axis direction", the direction parallel to the Y'axis is referred to as the "Y'axis direction", and the direction parallel to the Z'axis is referred to as the "Z'axis direction". In addition, the tip direction of the arrows of the X-axis, the Y'axis, and the Z'axis is referred to as "+ (positive)", and the direction opposite to the arrow is referred to as "- (negative)".

[0030] like Figure 1 As shown in FIG. 1 , the crystal vibrator 1 includes a crystal vibrating element 10, a cover member 20, and a base substrate 30. The cover member 20 includes an intermediate layer 40 and a sealing layer 50. The cover member 20 and the base substrate 30 constitute a holder for accommodating the crystal vibrating element 10. Figure 1 to Figure 3 In the example shown, the sides of the cover member 20 and the base substrate 30 facing each other are formed into a concave shape. Specifically, the cover member 20 has a bottomed opening portion for accommodating the crystal vibrating element 10 on the base substrate 30 side, and the base substrate 30 has a bottomed opening portion separated from the crystal vibrating element 10 on the cover member 20 side. The shapes of the cover member 20 and the base substrate 30 are not limited to the above shapes, and the base substrate 30 may have a bottomed opening portion for accommodating the crystal vibrating element 10 on the cover member 20 side. In addition, at least one of the cover member 20 and the base substrate 30 may be formed into a flat plate shape.

[0031] The crystal vibrating element 10 is an element that converts electric energy and mechanical energy by vibrating crystal through piezoelectric effect. The crystal vibrating element 10 includes: a thin crystal plate 11, a first excitation electrode 14a and a second excitation electrode 14b constituting a pair of excitation electrodes, a first extraction electrode 15a and a second extraction electrode 15b constituting a pair of extraction electrodes, and a first connection electrode 16a and a second connection electrode 16b constituting a pair of connection electrodes.

[0032] The crystal piece 11 has an upper surface 11A and a lower surface 11B facing each other. The upper surface 11A is located on the side opposite to the side facing the base substrate 30, that is, on the side facing the top surface 41 of the intermediate layer 40 described later. The lower surface 11B is located on the side facing the base substrate 30.

[0033] The crystal piece 11 is, for example, an AT-cut crystal piece. The AT-cut crystal piece 11 is formed such that, in an orthogonal coordinate system consisting of mutually intersecting X-axis, Y′-axis, and Z′-axis, a plane parallel to a plane defined by the X-axis and the Z′-axis (hereinafter referred to as “XZ′ plane”. The same applies to planes defined by other axes) is the main plane, and a direction parallel to the Y′-axis is the thickness. For example, the AT-cut crystal piece 11 is formed by etching a crystal substrate (for example, a crystal wafer), which is obtained by cutting and grinding a crystal of a synthetic crystal (Synthetic Quartz Crystal).

[0034] The crystal vibrator element 10 using the AT-cut crystal piece 11 has high frequency stability in a wide temperature range. In the AT-cut crystal vibrator element 10, the thickness shear vibration mode (Thickness Shear Vibration Mode) is used as the main vibration. In addition, the rotation angles of the Y' axis and the Z' axis in the AT-cut crystal piece 11 can also be tilted from 35 degrees and 15 minutes in the range of more than -5 degrees and less than 15 degrees. The cutting angle of the crystal piece 11 can also apply different cutting methods other than AT cutting. For example, BT cutting, GT cutting, SC cutting, etc. can also be applied. In addition, the crystal vibrator element can also be a tuning fork type crystal vibrator element using a crystal piece with a cutting angle called a Z plate.

[0035] The AT-cut crystal piece 11 is in the shape of a plate having a long side direction in which the long sides extend parallel to the X-axis direction, a short side direction in which the short sides extend parallel to the Z′-axis direction, and a thickness direction in which the thickness extends parallel to the Y′-axis direction. The crystal piece 11 is rectangular in shape when looking down at the upper surface 11A, and includes an excitation portion 17 located in the center and contributing to excitation, and peripheral portions 18 and 19 adjacent to the excitation portion 17. The excitation portion 17 is equivalent to a mechanical vibration portion. The peripheral portion 18 is a portion of the peripheral portion adjacent to the excitation portion 17 that is located on the -X-axis direction side when viewed from the excitation portion 17. The peripheral portion 19 is a portion of the peripheral portion adjacent to the excitation portion 17 that is located on the +X-axis direction side when viewed from the excitation portion 17. The excitation portion 17 and the peripheral portions 18 and 19 are each formed in a band shape in the range from one end to the other end opposite to each other in the Z′-axis direction of the crystal piece 11. As shown in FIG. Figure 2 As shown, in this embodiment, the excitation portion 17 and the peripheral portions 18 and 19 each have a rectangular shape in a plan view.

[0036] In addition, when looking down at the upper surface 11A of the crystal plate 11, the planar shape of the excitation portion 17 is not limited to the above-mentioned shape. The peripheral portion 19 may be omitted, and the excitation portion 17 may be formed within the range of substantially the entire surface of the portion on the +X axis direction side of the crystal plate 11. In addition, the excitation portion 17 may be formed in an island shape surrounded by the peripheral portion on the entire circumference. In addition, the shape of the excitation portion 17 may be a circle, an ellipse, a polygon, or a combination thereof.

[0037] The excitation portion 17 is thicker than the peripheral portions 18 and 19. The crystal plate 11 has a double-sided mesa structure. Thus, the vibration leakage from the excitation portion 17 can be suppressed. Figure 1 and Figure 3 In the example shown, the excitation portion 17 protrudes from the peripheral portions 18 and 19 along the Y′-axis direction on both the upper surface 11A side and the lower surface 11B side of the quartz crystal 11. In other words, steps are formed at the boundary between the excitation portion 17 and the peripheral portion 18, and at the boundary between the excitation portion 17 and the peripheral portion 19 on both the upper surface 11A side and the lower surface 11B side of the quartz crystal 11. The shape of the step at the boundary between the excitation portion 17 and the peripheral portions 18 and 19 is, for example, a cone shape, but may also be other shapes such as a multi-step shape.

[0038] The cross-sectional shape of the crystal plate 11 is not limited to the above-mentioned shape, and may be, for example, a single-sided mesa structure in which the excitation portion 17 protrudes from the peripheral portions 18 and 19 only on one side of the upper surface 11A and the lower surface 11B, or an inverted mesa structure in which the excitation portion 17 is thinner than the peripheral portions 18 and 19. The crystal plate 11 may also be a convex structure or an inclined structure in which the amount of thickness change continuously changes between the excitation portion 17 and the peripheral portions 18 and 19. In addition, the shape of the crystal plate 11 is not limited to a plate shape, and may be, for example, a tuning fork shape having a base and a vibrating arm portion extending in parallel from the base. The shape of the crystal plate 11 may also be a flat plate in which the thickness of the excitation portion 17 is substantially equal to the thickness of the peripheral portions 18 and 19. For the purpose of suppressing vibration leakage and stress transmission, a slit may also be formed in the peripheral portion 18.

[0039] The first excitation electrode 14a is provided on the upper surface 11A side of the excitation portion 17. In addition, the second excitation electrode 14b is provided on the lower surface 11B side of the excitation portion 17. In other words, the first excitation electrode 14a is provided on the cover member 20 side, and the second excitation electrode 14b is provided on the base substrate 30 side. The first excitation electrode 14a and the second excitation electrode 14b are opposed to each other with the crystal plate 11 sandwiched therebetween. When the upper surface 11A of the crystal plate 11 is viewed from above, the first excitation electrode 14a and the second excitation electrode 14b are arranged so as to overlap substantially as a whole. The first excitation electrode 14a and the second excitation electrode 14b each have a long side parallel to the X-axis direction, a short side parallel to the Z′-axis direction, and a thickness parallel to the Y′-axis direction.

[0040] The first extraction electrode 15a electrically connects the first excitation electrode 14a and the first connection electrode 16a. The second extraction electrode 15b electrically connects the second excitation electrode 14b and the second connection electrode 16b. Figure 2 As shown, the first extraction electrode 15a extracted from the first excitation electrode 14a extends in the X-axis direction and is provided on the step on the upper surface 11A side of the boundary between the excitation portion 17 and the peripheral portion 18 and on the upper surface 11A of the peripheral portion 18. In addition, the second extraction electrode 15b extracted from the second excitation electrode 14b extends in the X-axis direction and is provided on the step on the lower surface 11B side of the boundary between the excitation portion 17 and the peripheral portion 18 and on the lower surface 11B of the peripheral portion 18. From the viewpoint of reducing parasitic capacitance, the first extraction electrode 15a and the second extraction electrode 15b are separated from each other when the upper surface 11A of the crystal plate 11 is viewed from above, and the first extraction electrode 15a is provided in the +Z′ axis direction when viewed from the second extraction electrode 15b.

[0041] The first connection electrode 16a and the second connection electrode 16b are electrodes for electrically connecting the first excitation electrode 14a and the second excitation electrode 14b to the base substrate 30, and are provided on the lower surface 11B side of the peripheral portion 18. Figure 2 As shown, the first connection electrode 16a and the second connection electrode 16b are arranged at the end of the peripheral portion 18 on the -X axis direction side. The first connection electrode 16a is arranged at the corner on the +Z′ axis direction side, and the second connection electrode 16b is arranged at the corner on the -Z′ axis direction side.

[0042] The first excitation electrode 14a, the first extraction electrode 15a and the first connection electrode 16a are formed integrally. The same is true for the second excitation electrode 14b, the second extraction electrode 15b and the second connection electrode 16b. The electrodes of the above-mentioned crystal vibration element 10 are provided by, for example, stacking chromium (Cr) and gold (Au) in sequence. In terms of adhesion to the crystal plate 11, chromium is superior to gold, and in terms of chemical stability, gold is superior to chromium. Therefore, in the case where the electrodes of the crystal vibration element 10 are a multilayer structure consisting of chromium and gold, a crystal vibration element 10 that can suppress peeling and oxidation of the electrodes and has high reliability can be provided.

[0043] The base substrate 30 holds the crystal vibrating element 10 in an excitable manner. The base substrate 30 includes a base 31 having an upper surface 31A and a lower surface 31B facing each other. The upper surface 31A is located on the side of the crystal vibrating element 10 and the cover member 20, and corresponds to a mounting surface for mounting the crystal vibrating element 10. An opening 39 with a bottom is formed on the upper surface 31A side of the base substrate 30. The opening 39 overlaps a portion of the electronic component. Figure 2As shown, in the present embodiment, the opening 39 of the base substrate 30 overlaps with the entire excitation portion 17 and the peripheral portion 19 of the crystal vibrating element 10 and a portion of the peripheral portion 18. When looking down at the upper surface 31A, the end faces of the base 31 are cylindrically recessed at the four corners toward the center of the base 31. The base 31 is, for example, a sintered material of insulating ceramic (alumina) or the like. From the viewpoint of suppressing the generation of thermal stress, the base 31 is preferably made of a heat-resistant material. From the viewpoint of suppressing the stress applied to the crystal vibrating element 10 due to thermal history, the base 31 may also be provided by a material having a thermal expansion coefficient close to that of the crystal plate 11, for example, may also be provided by crystal.

[0044] The base substrate 30 includes a first electrode pad 33a and a second electrode pad 33b which form a pair of electrode pads provided on the upper surface 31A of the base body 31. The first electrode pad 33a and the second electrode pad 33b are terminals for electrically connecting the crystal vibrating element 10 to the base substrate 30. Figure 2 As shown, at least a portion of the first electrode pad 33a overlaps with the first connection electrode 16a, and at least a portion of the second electrode pad 33b overlaps with the second connection electrode 16b.

[0045] The base substrate 30 includes a first cast electrode 35a, a second cast electrode 35b, a third cast electrode 35c, and a fourth cast electrode 35d provided on the surface of the concave portions formed at the four corners of the end surface of the base body 31. Figure 2 As shown, when the upper surface 31A of the base substrate 30 is viewed from above, the second cast electrode 35b is located on the -Z' axis direction side when viewed from the first cast electrode 35a, the third cast electrode 35c is located on the +X axis direction side when viewed from the second cast electrode 35b, and the fourth cast electrode 35d is located on the +Z' axis direction side when viewed from the third cast electrode 35c. For example, the crystal oscillator 1 is mounted on an external circuit substrate (not shown) by soldering the first cast electrode 35a, the second cast electrode 35b, the third cast electrode 35c, and the fourth cast electrode 35d. At this time, the first cast electrode 35a and the second cast electrode 35b are terminals for electrically connecting the external circuit substrate (not shown) and the crystal oscillator 1. The third cast electrode 35c and the fourth cast electrode 35d are virtual electrodes that do not input or output electrical signals, but may also be ground electrodes that ground at least a portion of the cover member 20 to improve the electromagnetic shielding function of the cover member 20. Furthermore, the first casting electrode 35a, the second casting electrode 35b, the third casting electrode 35c, and the fourth casting electrode 35d may be electrodes that electrically connect the electrodes on the upper surface 31A side of the base substrate 30 and the external electrodes on the lower surface 31B side. Such welding between the crystal oscillator 1 and the external circuit substrate may also be performed through the external electrodes on the lower surface 31B side.

[0046] The base substrate 30 includes a first base wiring 34a and a second base wiring 34b constituting a pair of base wirings provided on the upper surface 31A of the base body 31. The first base wiring 34a electrically connects the first electrode pad 33a and the first cast electrode 35a, and the second base wiring 34b electrically connects the second electrode pad 33b and the second cast electrode 35b.

[0047] A first conductive holding member 36a and a second conductive holding member 36b constituting a pair of conductive holding members are provided on the upper surface 31A side of the base substrate 30. Specifically, the first conductive holding member 36a is provided on the first electrode pad 33a, and the second conductive holding member 36b is provided on the second electrode pad 33b. The first conductive holding member 36a and the second conductive holding member 36b mount the crystal vibrating element 10 on the base substrate 30, and electrically connect the crystal vibrating element 10 and the base substrate 30. The first conductive holding member 36a is bonded to the first connection electrode 16a of the crystal vibrating element 10, and the first electrode pad 33a and the first connection electrode 16a are electrically connected. The second conductive holding member 36b is bonded to the second connection electrode 16b of the crystal vibrating element 10, and the second electrode pad 33b and the second connection electrode 16b are electrically connected. The first conductive holding member 36a and the second conductive holding member 36b hold the crystal vibrating element 10 at a distance from the base substrate 30 so that the excitation section 17 can be excited. The first conductive holding component 36a and the second conductive holding component 36b are, for example, conductive adhesives containing thermosetting resins, ultraviolet curing resins, etc., with silicone resin as the main agent, and contain additives such as conductive particles for imparting conductivity to the adhesive. As conductive particles, for example, conductive particles containing silver (Ag) are used. The main agent of the conductive adhesive may also be epoxy resin, etc. After applying an uncured conductive adhesive paste as a precursor, the conductive adhesive paste is cured by a chemical reaction caused by heating, ultraviolet irradiation, etc., thereby setting the first conductive holding component 36a and the second conductive holding component 36b. In addition, fillers may be added to the adhesive for the purpose of increasing strength or maintaining the interval between the base substrate 30 and the crystal vibrating element 10. In addition, the first conductive holding component 36a and the second conductive holding component 36b may also be set by solder.

[0048] An internal space 49 for accommodating the crystal vibrating element 10 is formed between the intermediate layer 40 and the base substrate 30. The intermediate layer 40 includes: a flat top portion 41 that sandwiches the crystal vibrating element 10 and is opposed to the opening portion 39 of the base substrate 30, and a side wall portion 42 that is connected to the outer edge of the top portion 41 and extends in a direction intersecting the top portion 41. The side wall portion 42 surrounds the crystal vibrating element 10 in the Z′X plane direction. The intermediate layer 40 has an inner surface 44 on the side of the internal space 49 and an outer surface 45 on the side opposite to the inner surface 44. The intermediate layer 40 has an opposing surface 43 at the front end of the side wall portion 42 on the base substrate 30 side. Figure 2 As shown, when looking down at the upper surface 31A of the base substrate 30, the facing surface 43 is in a rectangular frame shape surrounding the crystal vibrating element 10 and is bonded to the base 31. In addition, the facing surface 43 covers a portion of each of the first base wiring 34a and the second base wiring 34b. The intermediate layer 40 is provided by, for example, polysilicon, silicon oxide, or the like.

[0049] At least one through hole 46 is formed in the middle layer 40 to open the internal space 49 to the outside. The through hole 46 is formed in the top surface 41 and is open on both sides of the inner surface 44 and the outer surface 45. Figure 2 As shown in FIG. 1 , when the upper surface 31A of the base substrate 30 is viewed from above, at least a portion of the plurality of through holes 46 is formed in a region overlapping with the opening 39 of the base substrate 30. A portion of the plurality of through holes 46 may be located outside the opening 39. A portion of the plurality of through holes 46 overlapping with the opening 39 of the base substrate 30 overlaps with the crystal vibrating element 10, and a portion is located outside the crystal vibrating element 10. By dispersing the positions of the plurality of through holes 46, the sacrificial layer can be efficiently removed in the manufacturing process, and the generation of residues of the sacrificial layer in the opening 39 and the internal space 49 can be suppressed.

[0050] When viewed from the internal space 49, the sealing layer 50 is disposed on the outside of the intermediate layer 40, and blocks the through-holes 46 to seal the internal space 49. The sealing layer 50 covers the intermediate layer 40, and includes a flat top portion 51, and a side wall portion 52 connected to the outer edge of the top portion 51 and extending in a direction intersecting the top portion 51. The sealing layer 50 has an inner surface 54 on the intermediate layer 40 side, and an outer surface 55 on the side opposite to the inner surface 54. The sealing layer 50 has an opposing surface 53 at the front end of the side wall portion 52 on the base substrate 30 side. The inner surface 54 of the sealing layer 50 contacts the outer surface 45 of the intermediate layer 40, and blocks the through-holes 46 on the top portion 51. As shown in FIG. Figure 2As shown, when looking down at the upper surface 31A of the base substrate 30, the opposing surface 53 is in the shape of a rectangular frame surrounding the crystal vibrating element 10, and is bonded to the base 31. In addition, the opposing surface 53 covers a portion of each of the first base wiring 34a and the second base wiring 34b. The sealing layer 50 is provided, for example, by silicon nitride or the like. The sealing layer 50 can also be provided, for example, by a conductive material such as metal, in which case the sealing layer 50 can be given an electromagnetic shielding function that reduces the entry and exit of electromagnetic waves into the internal space 49. In addition, when the sealing layer 50 is provided by a conductive material, the sealing layer 50 is provided separately from the first base wiring 34a and the second base wiring 34b. In this case, the sealing layer 50 can also be electrically connected to the third cast electrode 35c or the fourth cast electrode 35d.

[0051] (Manufacturing method)

[0052] Next, refer to Figures 4 to 10 , while describing a method for manufacturing the crystal oscillator 1 according to the first embodiment. Figure 4 This is a flow chart schematically showing the method for manufacturing the crystal oscillator according to the first embodiment. Figure 5 It is a plan view schematically showing a substrate preparation step of preparing an aggregate substrate. Figure 6 This is a cross-sectional view schematically showing a mounting step of mounting a crystal resonator element. Figure 7 It is a cross-sectional view schematically showing an intermediate layer forming step of providing an intermediate layer. Figure 8 It is a cross-sectional view schematically showing a space forming step of removing the first sacrificial layer and the second sacrificial layer. Fig. 9 It is a cross-sectional view schematically showing a sealing step of providing a sealing layer. Fig.10 A plan view schematically showing the separation step for individual chips.

[0053] First, the collective substrate 130 is prepared (substrate preparation step). The substrate preparation step includes a step S11 of preparing a mother substrate, a step S12 of forming via holes in the mother substrate, and a step S13 of providing electrode pads, via hole electrodes, and base wiring.

[0054] In the step S11 of preparing the mother substrate, a ceramic powder using alumina as the main raw material is used to form a green sheet. Next, in the step S12 of forming via holes in the mother substrate, an opening 39 and a via hole VH are formed in the green sheet. Next, in the step S13 of providing electrode pads, via hole electrodes and base wiring, a first electrode pad 33a and a second electrode pad 33b, a first base wiring 34a and a second base wiring 34b, and a via hole electrode VE are provided on the green sheet by a vapor deposition method such as physical vapor deposition (PVD: Physical Vapor Deposition) and chemical vapor deposition (CVD: Chemical Vapor Depositon). The via hole electrode VE is provided in a hollow cylindrical shape to cover the inner side surface of the via hole VH. Next, the green sheet is fired at about 1600°C in a hydrogen atmosphere. Thus, as Figure 5 As shown, a mother substrate 131 composed of ceramic (alumina) is formed to obtain a collective substrate 130. At this time, the mother substrate 131 shrinks by firing, for example, by about 20%. In addition, the first electrode pad 33a and the second electrode pad 33b, the first base wiring 34a and the second base wiring 34b, and the via electrode VE can also be provided by a film forming method other than vapor deposition such as electroplating and printing. In addition, the opening 39 and the via VH can also be formed after the green sheet is fired. At this time, the first electrode pad 33a and the second electrode pad 33b, the first base wiring 34a and the second base wiring 34b, and the via electrode VE can also be formed after the green sheet is fired.

[0055] Next, a first sacrificial layer is provided (sacrificial layer forming step S14 ).

[0056] like Figure 6 As shown, the first sacrificial layer 121 is disposed inside the opening 39 of the collective substrate 130. The material of the first sacrificial layer 121 is not particularly limited as long as it can be removed by wet etching or dry etching, and for example, silicon oxide, amorphous silicon, photoresist, other polymer materials, etc. can be appropriately selected.

[0057] Next, a crystal resonator element is mounted (mounting step S15 ).

[0058] In this process, if Figure 6 As shown, first, an uncured and paste-like conductive adhesive 137 is applied to the first electrode pad 33a and the second electrode pad 33b by, for example, a dispenser. The coating method of the conductive adhesive 137 is not limited to the above, and can also be provided by gravure printing, screen printing, inkjet printing, etc. Next, the excitation part 17 of the crystal vibration element 10 is supported on the first sacrificial layer 121, and the conductive adhesive 137 is sandwiched between the collective substrate 130 and the crystal vibration element 10. Next, as shown in FIG. Figure 7 As shown, the conductive adhesive 137 is cured while the excitation portion 17 of the crystal vibrating element 10 is supported by the first sacrificial layer 121. The portion supported by the first sacrificial layer 121 is not limited to the excitation portion 17, and may be the peripheral portion 18 or the peripheral portion 19 as long as it is a part of the crystal vibrating element 10.

[0059] Next, a second sacrificial layer is provided (sacrificial layer covering step S16 ).

[0060] The second sacrificial layer 122 is provided to cover the crystal vibrating element 10. The second sacrificial layer 122 is appropriately selected from the same material as the first sacrificial layer 121.

[0061] Next, an intermediate layer is provided (S17).

[0062] like Figure 7 As shown, the intermediate layer 40 covers the second sacrificial layer 122 and contacts the collective substrate 130. The intermediate layer 40 is formed to cover a portion of the base wiring. The formation method of the intermediate layer 40 is appropriately selected from PVD, CVD, etc. The film thickness of the intermediate layer 40 is set to have a strength that can maintain the internal space 49 after the second sacrificial layer 122 is removed.

[0063] Next, through holes are formed in the intermediate layer ( S18 ).

[0064] For example, at least one through hole 46 is formed in one intermediate layer 40 by dry etching using photolithography. By forming the through hole 46, the second sacrificial layer 122 is exposed to the outside through the through hole 46. The size of the through hole 46 is set so that in the sealing step S20 of providing the sealing layer 50 described later, the material forming the sealing layer 50 does not intrude into the internal space 49 through the through hole 46. In addition, the through hole 46 may be formed at a position that does not overlap with the crystal vibrating element 10, so that even if the material forming the sealing layer 50 intrudes into the internal space 49, it does not adhere to the crystal vibrating element 10 and change the resonance frequency.

[0065] The intermediate layer forming step of this embodiment includes step S17 and step S18, but is not limited thereto. The intermediate layer forming step may, for example, first provide a photoresist at the position where the through hole 46 is to be formed, form an intermediate layer on the second sacrificial layer 122 and the photoresist, and remove the photoresist together with the intermediate layer formed thereon to form the intermediate layer 40 having the through hole 46 formed thereon.

[0066] Next, the first sacrificial layer and the second sacrificial layer are removed (space forming step S19 ).

[0067] The first sacrificial layer 121 and the second sacrificial layer 122 are processed by removing the through hole 46 of the intermediate layer 40, for example, by dry etching or wet etching. Figure 8 As shown, the opening 39 of the assembly substrate 130 becomes a cavity by removing the first sacrificial layer 121, and the internal space 49 of the intermediate layer 40 becomes a cavity by removing the second sacrificial layer 122. When a photoresist is used as the first sacrificial layer 121 and the second sacrificial layer 122, for example, a solution that dissolves the photoresist but does not react with the crystal plate 11 of the crystal vibrating element 10 and various electrodes is appropriately selected.

[0068] Next, a sealing layer is provided (sealing step S20 ).

[0069] like Fig. 9 As shown, the sealing layer 50 is provided on the outside of the intermediate layer 40 to cover the entire surface of the intermediate layer 40, and the through hole 46 is blocked to seal the internal space 49 and the opening 39. The sealing layer 50 is formed to be in contact with the collective substrate 130 and to cover a part of the base wiring. The method for forming the sealing layer 50 is appropriately selected from, for example, PVD, CVD, etc. The film thickness of the sealing layer 50 is set to have a strength that can maintain the opening 39 of the base substrate 30 and the internal space 49 of the intermediate layer 40 together with the intermediate layer 40.

[0070] In addition, the manufacturing method of the crystal oscillator 1 may also include a heating step of heating the intermediate layer 40 to seal the through hole 46 before the sealing step S20. Such a heating step is not limited to completely sealing the through hole 46, but may also reduce the size of the through hole 46 to facilitate the subsequent sealing step S20.

[0071] Finally, the collective substrate is divided into individual pieces (dividing step S21 ).

[0072] The collective substrate 130 is cut along the score line to separate into a plurality of crystal oscillators 1. The collective substrate 130 is cut using a cutting device using, for example, a laser or a dicing saw. The score line is set to cross the via hole VH, and the via hole electrode VE is divided as the collective substrate 130 is cut. The divided via hole electrode VE forms a casting electrode of the crystal oscillator 1.

[0073] As described above, the crystal oscillator 1 of the first embodiment comprises: a base substrate 30, which is formed with a bottomed opening portion 39 overlapping a portion of the crystal oscillator element 10; an intermediate layer 40, which is bonded to the base substrate 30 and is formed with at least one through hole 46; and a sealing layer 50, which is arranged on the outer side of the intermediate layer 40 and blocks the through hole 46 to seal the internal space 49. In addition, the manufacturing method of the crystal oscillator 1 of the first embodiment comprises: a substrate preparation step, including step S11, step S12 and step S13; a sacrificial layer forming step S14, in which a first sacrificial layer 121 is set on the collective substrate 130; a mounting step S15, in which a part of the crystal oscillator element 10 is supported on the first sacrificial layer 121 and mounted on the collective substrate 130; a sacrificial layer covering step S16, in which the crystal oscillator element 10 is covered with a second sacrificial layer 122; an intermediate layer forming step, including steps S17 and S18 of covering the second sacrificial layer 122 with an intermediate layer 40 having at least one through hole 46 formed therein; a space forming step S19, in which the first sacrificial layer 121 and the second sacrificial layer 122 are removed through the through hole 466; a sealing step S20, in which the through hole 46 is sealed with a sealing layer 50 to seal the internal space 49; and a splitting step S21, in which the collective substrate 130 is split to form a cast electrode.

[0074] Thus, by manufacturing at the wafer level, a low-cost and small electronic device can be provided. In addition, compared with an electronic device that surrounds the mechanical vibration portion and fixes the entire circumference of the end of the electronic component using a base substrate, a cover member, etc., the transmission of stress to the mechanical vibration portion can be reduced. Therefore, according to this embodiment, an electronic device and a manufacturing method thereof that has a small frequency change caused by stress and can be miniaturized can be provided. In addition, when the electronic component is mounted on the base substrate, a part of the electronic component is supported by the first sacrificial layer until the conductive adhesive is cured, thereby stabilizing the installation posture of the electronic component and preventing physical interference between the electronic component and the base substrate.

[0075] The following describes the structure of the stress sensor of another embodiment of the present invention. In addition, in the following embodiments, the matters common to the first embodiment described above are omitted, and only the differences are described. In particular, the same effects based on the same structure are not mentioned in sequence.

[0076] <Second Embodiment>

[0077] One side reference Fig.11 , while describing the structure of the crystal oscillator 2 according to the second embodiment. Fig.11 It is a cross-sectional view schematically showing the structure of a crystal oscillator according to the second embodiment.

[0078] The second embodiment is different from the first embodiment in that no opening is formed in the base 231 of the base substrate 230, and the crystal vibrating element 210 is mounted on the planar upper surface 231A. The crystal vibrating element 210 is mounted with the first conductive holding member 236a as the starting point so that the peripheral portion 219 is further away from the base substrate 230 than the peripheral portion 218. Such a crystal vibrator 1 is realized, for example, by supporting the peripheral portion 219 on the first sacrificial layer and mounting the crystal vibrating element 210 on the base substrate 230. In addition, the through hole 246 is formed in the intermediate layer 240 and the through hole 246 is sealed by the sealing layer 250, which is the same as the first embodiment.

[0079] According to this embodiment, the electronic component can be held at an arbitrary angle relative to the base substrate. In addition, in the manufacturing process, the front end of the electronic component is supported by the first sacrificial layer, so that the mounting angle of the electronic component can be easily adjusted. In addition, even if the mounting surface of the base substrate is flat, these effects can be obtained.

[0080] <Third Embodiment>

[0081] One side reference Fig.12 , while describing the structure of the crystal oscillator 3 according to the second embodiment. Fig.12 It is a cross-sectional view schematically showing the structure of a crystal oscillator according to the third embodiment.

[0082] The third embodiment is different from the first embodiment in that the crystal vibrating element 310 is bonded to the base substrate 330 via the peripheral portion 318 and the peripheral portion 319, which is a so-called double support structure. The peripheral portion 318 is bonded to the base substrate 330 via the first conductive holding member 336a, and the peripheral portion 319 is bonded to the base substrate 330 via the second conductive holding member 336b. In addition, the opening portion 339 is formed on the upper surface 331A side of the base 331, the through hole 346 is formed in the intermediate layer 340, and the through hole 346 is sealed by the sealing layer 350, which is the same as the first embodiment.

[0083] In such an embodiment as well, it is possible to provide an electronic device and a method for manufacturing the same that has a small frequency variation due to stress and can be miniaturized, and further, the mounting posture of the electronic component can be stabilized.

[0084] <Fourth Embodiment>

[0085] One side reference Fig.13 , while describing the structure of the crystal oscillator 4 according to the fourth embodiment. Fig.13 It is a cross-sectional view schematically showing the structure of a crystal oscillator according to the fourth embodiment.

[0086] The fourth embodiment is different from the first embodiment in that a through electrode 435a is formed on the base 431 of the base substrate 430, and no cast electrode is provided on the end surface of the base substrate 430. The through electrode 435a penetrates the base 431 and electrically connects the electrode pad 433a on the upper surface 431A side of the base substrate 430 and the external electrode on the lower surface 431B side. When the upper surface 431A of the base substrate 430 is viewed from above, the through electrode 435a overlaps the intermediate layer 440. In addition, the aspects of forming the opening 439 on the upper surface 431A side of the base 431, forming the through hole 446 in the intermediate layer 440, and sealing the through hole 446 with the sealing layer 450 are the same as the first embodiment.

[0087] In this embodiment as well, the same effects as described above can be obtained.

[0088] Hereinafter, a part or all of the embodiments of the present invention will be supplemented to explain the effects thereof. In addition, the present invention is not limited to the following supplementary notes.

[0089] According to one embodiment of the present invention, there is provided an electronic device comprising: an electronic component having a mechanical vibration portion; a base substrate on which the electronic component is mounted; an intermediate layer, which forms an internal space for accommodating the electronic component with the base substrate and has at least one through hole opening the internal space to the outside; and a sealing layer, which is arranged on the outer side of the intermediate layer and blocks at least one through hole to seal the internal space, and an opening with a bottom overlapping with a portion of the electronic component is formed on the mounting surface of the base substrate on which the electronic component is mounted.

[0090] Thus, by manufacturing at the wafer level, a low-cost and small electronic device can be provided. In addition, compared with an electronic device that surrounds the mechanical vibration portion and fixes the entire circumference of the end of the electronic component using a base substrate, a cover member, etc., the transmission of stress to the mechanical vibration portion can be reduced. Therefore, according to this embodiment, an electronic device and a manufacturing method thereof that has a small frequency change caused by stress and can be miniaturized can be provided. In addition, when the electronic component is mounted on the base substrate, a part of the electronic component is supported by the first sacrificial layer until the conductive adhesive is cured, thereby stabilizing the installation posture of the electronic component and preventing physical interference between the electronic component and the base substrate.

[0091] In one embodiment, the base substrate includes: electrode pads provided on the mounting surface and bonded to the electronic component; cast electrodes provided on the end surface; and base wirings electrically connecting the electrode pads and the cast electrodes.

[0092] Thus, compared with an electronic device having a through electrode passing through a sealed internal space, since there is no leakage through the gap between the through electrode and the base body, a higher sealing performance can be obtained. In addition, the formation of the through electrode can be omitted, so that the manufacturing becomes easy.

[0093] In one embodiment, the sealing layer is bonded to the base substrate and covers a portion of the base wiring.

[0094] This can reduce leakage through the gap between the base wiring and the surrounding areas, thereby achieving high sealing performance.

[0095] In one embodiment, in a plan view of the mounting surface of the base substrate, at least one through hole is formed in a region overlapping with the opening.

[0096] Thus, the first sacrificial layer and the second sacrificial layer can be removed efficiently.

[0097] In one embodiment, in a plan view of the mounting surface of the base substrate, at least one through hole is formed outside a region overlapping with a mechanical vibration portion of the electronic component.

[0098] This can suppress adhesion of the sealing layer material to the mechanical vibration portion when the sealing layer is formed, thereby suppressing a change in the frequency of the mechanical vibration portion.

[0099] As one embodiment, the electronic component is a crystal vibration element.

[0100] According to another embodiment of the present invention, there is provided a method for manufacturing an electronic device, comprising: a substrate preparation step of preparing an aggregate substrate; a sacrificial layer formation step of providing a first sacrificial layer on the aggregate substrate; a mounting step of supporting a portion of an electronic component having a mechanical vibration portion on the first sacrificial layer and mounting the electronic component on the aggregate substrate; a sacrificial layer covering step of covering the electronic component with a second sacrificial layer; an intermediate layer formation step of covering the second sacrificial layer with an intermediate layer, and forming at least one through hole in the intermediate layer that opens the second sacrificial layer side to its opposite side; a space forming step of removing the first sacrificial layer and the second sacrificial layer through at least one through hole to form an internal space between the aggregate substrate and the intermediate layer; and a sealing step of sealing the internal space by blocking at least one through hole with a sealing layer provided on the outside of the intermediate layer. Thus, by manufacturing at the wafer level, a low-cost and small electronic device can be provided. In addition, compared with an electronic device in which the entire circumference of the end of the electronic component is fixed by a base substrate, a cover component, etc. to surround the mechanical vibration portion, the transmission of stress to the mechanical vibration portion can be reduced. Therefore, according to this embodiment, an electronic device and a method for manufacturing the same can be provided that has a small frequency change caused by stress and can be miniaturized. Furthermore, when the electronic component is mounted on the base substrate, a portion of the electronic component is supported by the first sacrificial layer until the conductive adhesive is cured, thereby stabilizing the mounting posture of the electronic component and preventing physical interference between the electronic component and the base substrate.

[0101] In one embodiment, a bottomed opening that overlaps a portion of the electronic component is formed on a mounting surface of the collective substrate on which the electronic component is mounted, and the first sacrificial layer is provided in the opening.

[0102] This can shorten the distance between the electronic component and the base substrate, and reduce the height of the electronic device.

[0103] As one mode, the substrate preparation process includes: a process of preparing a mother substrate; a process of forming a via hole penetrating the mother substrate; and a process of providing a via hole electrode covering the inner side of the via hole. The method for manufacturing an electronic device also includes a segmentation process. In the segmentation process, after providing a sealing layer, the collective substrate is singulated, and the via hole electrodes after segmentation are used to form a casting electrode on the end surface of the base substrate. Thus, compared with the method for manufacturing an electronic device in which a through electrode is provided through a sealed internal space, since there is no leakage through the gap between the through electrode and the substrate, an electronic device with higher sealing can be manufactured. In addition, the formation of the through electrode can be omitted, so the manufacture of the electronic device becomes easy.

[0104] In one embodiment, electrode pads electrically connected to the electronic components and base wiring electrically connecting the electrode pads and the via electrodes are provided on the collective substrate, and the sealing layer is bonded to the collective substrate and covers a portion of the base wiring.

[0105] This can reduce leakage through the gap between the base wiring and the surrounding area, and thus it is possible to manufacture an electronic device with high sealing performance.

[0106] As one embodiment, the electronic component is a crystal vibration element.

[0107] As described above, according to one embodiment of the present invention, it is possible to provide an electronic device in which frequency variation due to stress is small and which can be reduced in size, and a method for manufacturing the same.

[0108] In addition, the embodiments described above are intended to facilitate understanding of the present invention and are not intended to limit the interpretation of the present invention. The present invention can be changed / improved without departing from its main purpose, and its equivalents are also included in the present invention. That is, as long as the technical personnel in the field have the characteristics of the present invention, the methods of applying appropriate design changes to the various embodiments are also included in the scope of the present invention. For example, the various elements and their configurations, materials, conditions, shapes, sizes, etc. of the various embodiments are not limited to the exemplified contents and can also be appropriately changed. For example, the vibration element and vibrator of the present invention can be used for timing devices or load sensors. In addition, the various elements of the various embodiments can be combined within the technically possible range, and the methods after combining them are also included in the scope of the present invention as long as they include the characteristics of the present invention.

[0109] Explanation of the reference numerals: 1… crystal oscillator; 10… crystal oscillator element; 11… crystal piece; 11A… upper surface; 11B… lower surface; 14a, 14b… excitation electrode; 15a, 15b… lead-out electrode; 16a, 16b… connection electrode; 17… excitation portion; 18, 19… peripheral portion; 30… base substrate; 31… base body; 31A… upper surface; 31B… lower surface; 33a, 33b… electrode pad; 34a, 34b… base wiring; 35a~35d… cast electrode; 36a, 36b… conductive retaining component; 39… opening; 40… intermediate layer; 46… through hole; 49… internal space; 50… sealing layer.

Claims

1. An electronic device comprising: An electronic component having a mechanical vibration portion; a base substrate carrying the electronic components; an intermediate layer, forming an internal space for accommodating the electronic components between the intermediate layer and the base substrate, and having at least one through hole for opening the internal space to the outside; as well as a sealing layer, disposed on the outer side of the intermediate layer, blocking the at least one through hole to seal the internal space, An opening having a bottom that overlaps a portion of the electronic component is formed on the mounting surface of the base substrate on which the electronic component is mounted. The base substrate has: An electrode pad is provided on the mounting surface and is bonded to the electronic component; A casting electrode is disposed on the end surface; and Base wiring electrically connects the electrode pad and the cast electrode, The sealing layer is bonded to the base substrate and covers a portion of the base wiring.

2. The electronic device according to claim 1, wherein: The at least one through hole is formed in a region overlapping with the opening when the mounting surface of the base substrate is viewed in plan.

3. The electronic device according to claim 1 or 2, wherein: The electronic component is a crystal vibrating element.

4. A method for manufacturing an electronic device, comprising: A substrate preparation step, preparing an assembly substrate; A sacrificial layer forming step of providing a first sacrificial layer on the collective substrate; a mounting step of supporting a part of an electronic component having a mechanical vibration portion on the first sacrificial layer and mounting the electronic component on the collective substrate; a sacrificial layer covering step of covering the electronic component with a second sacrificial layer; an intermediate layer forming step of covering the second sacrificial layer with an intermediate layer, wherein at least one through hole opening from the second sacrificial layer side to the opposite side is formed in the intermediate layer; a space forming step of removing the first sacrificial layer and the second sacrificial layer through the at least one through hole to form an internal space between the collective substrate and the intermediate layer; as well as a sealing step of sealing the at least one through hole with a sealing layer disposed outside the intermediate layer to seal the internal space, The substrate preparation process comprises: The process of preparing a master matrix; forming a via hole penetrating the mother substrate; and a step of providing a via hole electrode covering the inner side surface of the via hole, The method for manufacturing an electronic device further comprises a dividing step, in which after the sealing layer is provided, the collective substrate is separated into individual pieces, and the via hole electrodes after the division are used to form casting electrodes on the end surfaces of the base substrate. The integrated substrate is provided with electrode pads electrically connected to the electronic components and base wiring electrically connecting the electrode pads and the via electrodes. The sealing layer is bonded to the collective substrate and covers a portion of the base wiring.

5. The method for manufacturing an electronic device according to claim 4, wherein: An opening having a bottom that overlaps a part of the electronic component is formed on the mounting surface of the assembly substrate on which the electronic component is mounted. The first sacrificial layer is disposed in the opening.

6. The method for manufacturing an electronic device according to claim 4 or 5, wherein: The electronic component is a crystal vibrating element.

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