JP2024100359A - Manufacturing method of vibration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a vibration device for increasing the number of pieces obtained from a wafer.

SOLUTION: A manufacturing method of a vibration device 1 includes: a base wafer preparation step of preparing a base wafer 100 comprising a first face 10a, a second face 10b, a base individualization region R1 and a base boundary part R2; a vibration element mounting step of mounting a vibration element 30 at the side of the first face 10a; a lid wafer preparation step of preparing a lid wafer 200 comprising a third face 20a, a fourth face 20b, a lid individualization region R3, a lid boundary part R4 and a recess 201; a device wafer formation step of forming a device wafer 300 by joining the third face 20a of the lid wafer 200 to the first face 10a of the base wafer 100; a groove formation step of forming a groove which is opened at the side of the second face 10b along the base boundary part R2; and an individualization step of obtaining a plurality of vibration devices 1 by performing cutting along the base boundary part R2 and the lid boundary part R4 and individualizing the device wafer 300.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2024,JPO&INPIT

Description

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

For example, Patent Document 1 discloses a manufacturing method for manufacturing vibration devices by dividing a device wafer on which multiple vibration devices are integrally formed, into individual pieces using a dicing blade.

JP 2020-123928 A

However, in the manufacturing method described in Patent Document 1, when dicing the device wafer into individual pieces, in order to increase the number of pieces that can be taken from the device wafer and reduce the cost of vibration devices, the dicing width is designed to be narrow, and there is a risk of the blade being damaged when attempting to cut with a thin blade. On the other hand, when dicing is performed with a thick blade, the thickness of the wall formed by the side surface and cut surface inside the lid cavity becomes thin, so the width of the joint between the base and the lid becomes narrow and the joint strength decreases. To prevent this, the width of the joint, which corresponds to the thickness of the lid wall, must be designed wide, resulting in the problem of a reduced number of pieces that can be taken from the device wafer.

The method for manufacturing a vibration device includes a base wafer preparation process for preparing a base wafer having a first surface and a second surface in a front-back relationship, a plurality of base singulation areas, and a base boundary portion located at the boundary between adjacent base singulation areas; a vibration element mounting process for mounting a vibration element on the first surface side of each of the base singulation areas; a lid wafer preparation process for preparing a lid wafer having a third surface and a fourth surface in a front-back relationship, a plurality of lid singulation areas, a lid boundary portion located at the boundary between adjacent lid singulation areas, and a recess formed in each of the lid singulation areas and opening to the third surface side; and a vibration element mounting process for mounting the vibration element on the first surface side of each of the lid singulation areas. The method includes a device wafer forming process in which the third surface of the lid wafer is bonded to the first surface of the base wafer by arranging the lid wafer so that the lid boundary and the base boundary overlap, and forming a device wafer; a groove forming process in which a groove is formed along the base boundary, the groove opening on the second surface side of the base wafer and having a bottom on the second surface side of the bond between the lid wafer and the base wafer; and a singulation process in which the device wafer is singulated to obtain a plurality of vibration devices by cutting along the base boundary and the lid boundary within the width of the groove between the bottom of the groove and the fourth surface side of the lid wafer.

The method for manufacturing a vibration device includes a base wafer preparation process for preparing a base wafer having a first surface and a second surface in a front-back relationship, a plurality of base singulation areas, and a base boundary portion located at the boundary between adjacent base singulation areas; a vibration element mounting process for mounting a vibration element on the first surface side of each of the base singulation areas; a lid wafer preparation process for preparing a lid wafer having a third surface and a fourth surface in a front-back relationship, a plurality of lid singulation areas, a lid boundary portion located at the boundary between adjacent lid singulation areas, and a recess formed in each of the lid singulation areas and opening to the third surface side; and a vibration element mounting process for mounting the vibration element on the first surface side of each of the lid singulation areas. The method includes a device wafer forming process in which the third surface of the lid wafer is bonded to the first surface of the base wafer by arranging the lid wafer so that the lid boundary and the base boundary overlap, and a device wafer is formed; a groove forming process in which a groove is formed along the lid boundary, the groove opening on the fourth surface side of the lid wafer and having a bottom on the fourth surface side of the bonded portion between the lid wafer and the base wafer; and a singulation process in which the device wafer is singulated to obtain a plurality of vibration devices by cutting along the lid boundary and the base boundary within the width of the groove between the bottom of the groove and the second surface side of the base wafer.

FIG. 1 is a perspective view showing a schematic structure of a vibration device according to a first embodiment. FIG. 1 is a plan view showing a schematic structure of a vibration device according to a first embodiment. Cross-sectional view taken along line A1-A1 in FIG. FIG. 4 is a flowchart showing a method for manufacturing the vibration device according to the first embodiment. 1A to 1C are cross-sectional views illustrating a method for manufacturing a vibration device. 1A to 1C are cross-sectional views illustrating a method for manufacturing a vibration device. 1A to 1C are cross-sectional views illustrating a method for manufacturing a vibration device. 1A to 1C are cross-sectional views illustrating a method for manufacturing a vibration device. 1A to 1C are cross-sectional views illustrating a method for manufacturing a vibration device. 1A to 1C are cross-sectional views illustrating a method for manufacturing a vibration device. 1A to 1C are cross-sectional views illustrating a method for manufacturing a vibration device. FIG. 11 is a perspective view showing a schematic structure of a vibration device according to a second embodiment. FIG. 11 is a plan view showing a schematic structure of a vibration device according to a second embodiment. Cross-sectional view taken along line A2-A2 in Figure 13. 1A to 1C are cross-sectional views illustrating a method for manufacturing a vibration device. 1A to 1C are cross-sectional views illustrating a method for manufacturing a vibration device. 1A to 1C are cross-sectional views illustrating a method for manufacturing a vibration device. FIG. 13 is a plan view showing a schematic structure of a vibration device according to a fifth embodiment. Cross-sectional view taken along line A3-A3 in Figure 18.

1. First embodiment 1.1. Vibration device First, a vibrator including a vibration element 30 will be described as an example of a vibration device 1 according to a first embodiment with reference to FIGS. 1, 2, and 3. FIG.
In addition, in FIG. 2, for the convenience of explaining the internal configuration of the vibration device 1, the lid 20 and the joining member 41 are removed. Also, for the convenience of explanation, the following perspective views, plan views, and cross-sectional views show three mutually perpendicular axes, the X-axis, the Y-axis, and the Z-axis. Also, the direction along the X-axis is called the "X-direction", the direction along the Y-axis is called the "Y-direction", and the direction along the Z-axis is called the "Z-direction". Also, the arrow side of each axis is called the "positive side", and the side opposite the arrow is called the "negative side". Also, the positive side of the Z direction is called the "upper side", and the negative side of the Z direction is called the "lower side".

As shown in Figures 1, 2, and 3, the vibration device 1 includes a base 10, a lid 20, and a vibration element 30. The base 10 and the lid 20 form a package 2 that houses the vibration element 30.

The base 10 is a rectangular flat plate when viewed from the Z direction, and has a first surface 10a and a second surface 10b, which are opposite surfaces, with an internal terminal 11 provided on the first surface 10a and an external terminal 13 provided on the second surface 10b. The base 10 is provided with a through electrode 12 that penetrates the first surface 10a and the second surface 10b, and is electrically connected to the internal terminal 11 and the external terminal 13. Silicon is preferable as a material for forming the base 10, but glass, ceramic, etc. may also be used.

The lid 20 is rectangular in plan view from the Z direction, has a third surface 20a and a fourth surface 20b that are in a front-back relationship, and has a recess 21 that opens to the third surface 20a side. The lid 20 is bonded to the first surface 10a of the base 10 via a bonding member 41, and together with the base 10, forms a storage space 22 that stores the vibration element 30. Therefore, the portion where the third surface 20a on the outer periphery of the recess 21 formed in the lid 20 and the first surface 10a of the base 10 are bonded via the bonding member 41 becomes the bonding portion 40. The inside of the storage space 22 is in a reduced pressure state, preferably a state closer to a vacuum. This reduces viscous resistance and improves the oscillation characteristics of the vibration element 30. Silicon is preferable as a constituent material of the lid 20, but glass, ceramic, etc. may also be used.

The base 10 and the lid 20 are bonded together by a method using glass frit or the like. However, the bonding method is not limited to this, and may be a metal eutectic bonding method in which metal films formed on the first surface 10a of the base 10 and the third surface 20a of the lid 20 are bonded together, or an activation bonding method in which the surface of the first surface 10a of the base 10 and the surface of a metal film such as Au formed on the third surface 20a of the lid 20 are activated by plasma irradiation to bond them together.

The vibration element 30 has a vibration substrate 31, an excitation electrode 32 that vibrates the vibration substrate 31, a pad electrode 34 that outputs a vibration signal to the outside and fixes the vibration element 30 to the base 10, a lead electrode 33 that electrically connects the excitation electrode 32 and the pad electrode 34, and a side electrode 35 that electrically connects the lead electrode 33 formed on the vibration substrate 31 and the pad electrode 34 formed under the vibration substrate 31.

The vibration element 30 is disposed on the first surface 10a side of the base 10, and is fixed to the base 10 at the pad electrode 34 via a conductive bonding member 42 such as a conductive adhesive or a gold bump. The vibration substrate 31 may be an AT-cut quartz substrate, an SC-cut quartz substrate, a BT-cut quartz substrate, or the like.

1.2 Manufacturing Method of the Vibration Device Next, a manufacturing method of the vibration device 1 according to the present embodiment will be described with reference to FIGS.
As shown in FIG. 4, the method for manufacturing the vibration device 1 of this embodiment includes a base wafer preparation step, a vibration element mounting step, a lid wafer preparation step, a device wafer formation step, a groove formation step, and a singulation step.

1.2.1. Base Wafer Preparation Process First, in step S1, in order to simultaneously manufacture a plurality of vibration devices 1, a base wafer 100 having a first surface 10a and a second surface 10b in a front-back relationship, a plurality of base singulation regions R1, and a base boundary portion R2 located at the boundary between adjacent base singulation regions R1, as shown in FIG. 5, is prepared. In the plurality of base singulation regions R1 of the base wafer 100, an internal terminal 11 for fixing the vibration element 30 on the first surface 10a side and an external terminal 13 for mounting the vibration device 1 on the second surface 10b side are formed. In addition, a through electrode 12 is also formed that penetrates the first surface 10a and the second surface 10b and electrically connects the internal terminal 11 and the external terminal 13. In addition, silicon is preferable as a constituent material of the base wafer 100, but glass, ceramic, etc. may also be used.

6, the vibration element 30 is attached to the first surface 10a side in the base singulation region R1 of the base wafer 100. More specifically, the vibration element 30 is placed on the internal terminal 11 formed in the base singulation region R1, and fixed via a conductive bonding member 42 such as a conductive adhesive or a gold bump.

1.2.3. Lid Wafer Preparation Step In step S3, in order to simultaneously manufacture a plurality of resonator devices 1, a lid wafer 200 is prepared, which has a third surface 20a and a fourth surface 20b, which are in a front-back relationship, a plurality of lid singulation regions R3, and a lid boundary portion R4 located at the boundary between adjacent lid singulation regions R3, as shown in FIG. In each lid singulation region R3, a recess 201 that opens to the third surface 20a side is formed. The recess 201 is formed by dry etching and corresponds to the recess 21 of the resonator device 1 after singulation. In addition, silicon is preferable as a constituent material of the lid wafer 200, but glass, ceramic, etc. may also be used.

8, in a plan view from the Z direction, the vibration element 30 is accommodated in the recess 201 of the lid wafer 200, and is arranged so that the lid boundary R4 and the base boundary R2 overlap. Thereafter, the third surface 20a of the lid wafer 200 is bonded to the first surface 10a of the base wafer 100 via a bonding member 41 such as glass frit, thereby forming a device wafer 300 in which the base wafer 100 to which the vibration element 30 is fixed and the lid wafer 200 are bonded.

9 , in step S5, the device wafer 300 is turned upside down, and the fourth surface 20b of the lid wafer 200 is attached to a dicing tape 60. After that, the base wafer 100 is diced from the second surface 10b side along the base boundary R2 with a first dicing blade, forming a groove 101 that opens on the second surface 10b side of the base wafer 100 and has a bottom closer to the second surface 10b side than the bonding portion 40 between the lid wafer 200 and the base wafer 100.

10, in step S6, the second dicing blade is used to cut between the bottom of the groove 101 and the fourth surface 20b of the lid wafer 200 within the width of the groove 101 along the base boundary R2 and the lid boundary R4, and the device wafer 300 is diced into individual pieces to obtain a plurality of vibration devices 1. Note that the thickness of the second dicing blade that cuts between the bottom of the groove 101 and the fourth surface 20b of the lid wafer 200 is smaller than the thickness of the first dicing blade that forms the groove 101. Therefore, the device wafer 300 can be efficiently diced into individual pieces.
Also, as shown in FIG. 11, after the groove forming process of step S5, the device wafer 300 may be turned upside down again, the second surface 10b of the base wafer 100 may be attached to a dicing tape 60, and the area between the fourth surface 20b of the lid wafer 200 and the bottom of the groove 101 may be cut along the lid boundary R4 and the base boundary R2.

As described above, in the manufacturing method of the vibration device 1 of this embodiment, in the groove forming step, a groove 101 that does not reach the bonded portion 40 is formed in the base wafer 100 with a thick first dicing blade, and in the singulation step, the device wafer 300 is cut with a second dicing blade that is thinner than the first dicing blade. This maintains the bonding strength of the bonded portion 40 between the base 10 and the lid 20, and increases the number of vibration devices 1 that can be obtained from the device wafer 300.

2. Second Embodiment Next, a vibration device 1a and a manufacturing method of the vibration device 1a according to a second embodiment will be described with reference to FIGS.
In addition, in FIG. 13, for the convenience of explaining the internal configuration of the vibration device 1a, the lid 20c and the joining member 41 are removed.

The vibration device 1a of this embodiment and the manufacturing method of the vibration device 1a are the same as those of the vibration device 1 of the first embodiment, except that the shapes of the base 10c and the lid 20c and the groove forming process and the singulation process in the manufacturing method are different from those of the vibration device 1 of the first embodiment. Note that the following description will focus on the differences from the first embodiment described above, and similar items will be given the same reference numerals and their description will be omitted.

12, 13, and 14, the vibration device 1a includes a base 10c, a lid 20c, and a vibration element 30. The base 10c and the lid 20c form a package 2a that houses the vibration element 30.

The cross-sectional shape of the base 10c is flat in the Z direction with no steps. The cross-sectional shape of the lid 20c has steps in the Z direction. This is because a groove 202 is formed on the lid 20c side in the groove forming process described below.

2.2. Manufacturing method of the vibration device The manufacturing method of the vibration device 1a of this embodiment includes a base wafer preparation process, a vibration element mounting process, a lid wafer preparation process, a device wafer formation process, a groove formation process, and a singulation process. Note that the base wafer preparation process, the vibration element mounting process, the lid wafer preparation process, and the device wafer formation process are the same as those of the first embodiment, so the description will be omitted.

15 , the second surface 10b side of the base wafer 100 of the device wafer 300 is attached to a dicing tape 60. Then, the lid wafer 200 is diced from the fourth surface 20b side along the lid boundary R4 with a first dicing blade to form a groove 202 that opens on the fourth surface 20b side of the lid wafer 200 and has a bottom closer to the fourth surface 20b side than the bonding portion 40 between the lid wafer 200 and the base wafer 100.

16, within the width range of the groove 202, a second dicing blade is used to cut between the bottom of the groove 202 and the second surface 10b of the base wafer 100 along the base boundary R2 and the lid boundary R4, and the device wafer 300 is diced into individual vibration devices 1. The thickness of the second dicing blade is smaller than the thickness of the first dicing blade that forms the groove 202.
Also, as shown in FIG. 17, after the groove forming process, the device wafer 300 may be turned upside down, the fourth surface 20b of the lid wafer 200 may be attached to a dicing tape 60, and the area between the second surface 10b of the base wafer 100 and the bottom of the groove 202 may be cut along the base boundary R2 and the lid boundary R4.

As described above, in the manufacturing method of the vibration device 1a of this embodiment, in the groove forming step, a groove 202 that does not reach the bond portion 40 is formed in the lid wafer 200 with a thick first dicing blade, and in the singulation step, the device wafer 300 is cut with a second dicing blade that is thinner than the first dicing blade. This maintains the bonding strength of the bond portion 40 between the base 10 and the lid 20, and increases the number of vibration devices 1a that can be obtained from the device wafer 300.

3. Third Embodiment Next, a method for manufacturing a vibration device according to a third embodiment will be described.

The method for manufacturing the vibration device of this embodiment is similar to the method for manufacturing the vibration device 1 of the first embodiment, except that the singulation process is different from the method for manufacturing the vibration device of the first embodiment. Note that the following description will focus on the differences from the first embodiment described above, and similar items will be given the same reference numerals and their description will be omitted.

The manufacturing method of the vibration device of this embodiment differs from the manufacturing method of the first embodiment in the singulation process. In the groove formation process, grooves 101 are formed with a dicing blade, and then in the singulation process, a laser is irradiated along the base boundary R2 and the lid boundary R4 within the width of the groove 101 between the bottom of the groove 101 and the fourth surface 20b of the lid wafer 200 to cut and singulate the groove 101.

In the method of manufacturing the vibration device of this embodiment, the cutting is performed by irradiating a laser during the singulation process, so the width of the cut portion can be made narrower and more precisely than when cutting with a dicing blade, and the number of vibration devices that can be obtained from the device wafer 300 can be increased.

4. Fourth Embodiment Next, a method for manufacturing a vibration device according to a fourth embodiment will be described.

The method for manufacturing the vibration device of this embodiment is similar to the method for manufacturing the vibration device 1 of the first embodiment, except that the singulation process is different from the method for manufacturing the vibration device of the first embodiment. Note that the following description will focus on the differences from the first embodiment described above, and similar items will be given the same reference numerals and their description will be omitted.

The manufacturing method of the vibration device of this embodiment differs from the manufacturing method of the first embodiment in the singulation process. In the groove formation process, a groove 101 is formed with a dicing blade, and then in the singulation process, a laser is focused inside the device wafer 300 along the base boundary R2 and the lid boundary R4 within the width of the groove 101 between the bottom of the groove 101 and the fourth surface 20b side of the lid wafer 200, and the inside of the device wafer 300 is modified, and then the device wafer 300 is cut like chocolate breaks and singulated.

In the method for manufacturing a vibration device according to this embodiment, a laser is focused in the singulation process to modify the inside of the device wafer 300 for cutting, which makes it possible to prevent scattering of the processed layer more effectively than cutting with a dicing blade, and because no water is used, contamination of the surface of the vibration device can be reduced, resulting in lower costs.

5. Fifth Embodiment Next, a vibration device 1b according to a fifth embodiment will be described with reference to FIGS.
In addition, in FIG. 18, for the convenience of explaining the internal configuration of the vibration device 1b, the lid 20 and the joining member 41 are removed.

The vibration device 1b of this embodiment is similar to the vibration device 1 of the first embodiment, except that the structure of the base 10d and the internal terminal 11b is different from that of the vibration device 1 of the first embodiment. Note that the following description will focus on the differences from the first embodiment described above, and similar items will be given the same reference numerals and their description will be omitted.

The vibration device 1b can be manufactured by the same manufacturing method as the vibration device 1 of the first embodiment, and includes a base 10d, a lid 20, and a vibration element 30, as shown in Figs. 18 and 19. The base 10d and the lid 20 form a package 2b that houses the vibration element 30.

The base 10d has a semiconductor substrate on which an oscillation circuit 50 is formed on the first surface 10a side. In addition, the internal terminal 11b to which the vibration element 30 is fixed via the conductive bonding member 42 is electrically connected to the oscillation circuit 50. Therefore, the vibration element 30 is electrically connected to the oscillation circuit 50.

In other words, in the manufacturing method of the vibration device 1b, the base wafer 100 includes a semiconductor substrate, and an oscillation circuit 50 electrically connected to the vibration element 30 is disposed on the semiconductor substrate in each base singulation region R1.

By configuring in this way, the vibration device 1b can be obtained as an oscillator equipped with a vibration element 30 and an oscillation circuit 50.

1, 1a, 1b... vibrating device, 2... package, 10... base, 10a... first surface, 10b... second surface, 11... internal terminal, 12... through electrode, 13... external terminal, 20... lid, 20a... third surface, 20b... fourth surface, 21... recess, 22... storage space, 30... vibrating element, 31... vibrating substrate, 32... excitation electrode, 33... lead electrode, 34... pad electrode, 35... side electrode, 40... bonding portion, 41... bonding member, 42... conductive bonding member, 50... oscillation circuit, 60... dicing tape, 100... base wafer, 101... groove, 200... lid wafer, 201... recess, 300... device wafer, R1... base singulation area, R2... base boundary, R3... lid singulation area, R4... lid boundary.

Claims (6)

A base wafer preparation process for preparing a base wafer having a first surface and a second surface in a front-back relationship, a plurality of base singulation regions, and a base boundary portion located at a boundary between adjacent base singulation regions;
a vibration element mounting step of mounting a vibration element on the first surface side in each of the base singulation regions;
a lid wafer preparation process for preparing a lid wafer having a third surface and a fourth surface which are in a front-back relationship, a plurality of lid singulation regions, a lid boundary portion located at a boundary between adjacent lid singulation regions, and a recess formed in each of the lid singulation regions and opening to the third surface side;
a device wafer forming process in which the vibration element is housed in the recess of the lid wafer and the lid boundary portion and the base boundary portion are arranged to overlap each other in a plan view, and the third surface of the lid wafer is bonded to the first surface of the base wafer to form a device wafer;
a groove forming step of forming a groove along the base boundary portion, the groove opening on the second surface side of the base wafer and having a bottom on the second surface side of a bonding portion between the lid wafer and the base wafer;
and a singulation process of cutting the device wafer between the bottom of the groove and the fourth surface side of the lid wafer along the base boundary and the lid boundary within a width range of the groove to singulate the device wafer to obtain a plurality of vibration devices.
A method for manufacturing a vibration device. A base wafer preparation process for preparing a base wafer having a first surface and a second surface in a front-back relationship, a plurality of base singulation regions, and a base boundary portion located at a boundary between adjacent base singulation regions;
a vibration element mounting step of mounting a vibration element on the first surface side in each of the base singulation regions;
a lid wafer preparation process for preparing a lid wafer having a third surface and a fourth surface which are in a front-back relationship, a plurality of lid singulation regions, a lid boundary portion located at a boundary between adjacent lid singulation regions, and a recess formed in each of the lid singulation regions and opening to the third surface side;
a device wafer forming process in which the vibration element is housed in the recess of the lid wafer and the lid boundary portion and the base boundary portion are arranged to overlap each other in a plan view, and the third surface of the lid wafer is bonded to the first surface of the base wafer to form a device wafer;
a groove forming step of forming a groove along a lid boundary portion, the groove opening on the fourth surface side of the lid wafer and having a bottom portion on the fourth surface side of a bonding portion between the lid wafer and the base wafer;
and a singulation process for cutting the bottom of the groove and the second surface side of the base wafer along the lid boundary and the base boundary within a width range of the groove to singulate the device wafer to obtain a plurality of vibration devices.
A method for manufacturing a vibration device. In the groove forming step, the groove is formed with a first dicing blade;
In the singulation step, cutting is performed with a second dicing blade having a thickness smaller than that of the first dicing blade.
A method for manufacturing a vibration device according to claim 1 or 2. In the groove forming step, the groove is formed with a dicing blade;
In the singulation step, cutting is performed by irradiating a laser.
A method for manufacturing a vibration device according to claim 1 or 2. In the groove forming step, the groove is formed with a dicing blade;
In the singulation step, a laser is focused on the inside of the device wafer to modify the inside, and then the device wafer is cut.
A method for manufacturing a vibration device according to claim 1 or 2. the base wafer includes a semiconductor substrate;
An oscillation circuit electrically connected to the vibration element is disposed on the semiconductor substrate in each of the base singulation regions.
A method for manufacturing a vibration device according to claim 1 or 2.

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