JP2012013493A - Manufacturing method for wafer level package structures - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a manufacturing method for wafer level package structures having no possibility of damage to electrical wiring, terminals and the like formed on the external faces of package wafers.SOLUTION: A manufacturing method comprises a step of holding a package wafer 10 with a holding device 4 and a sensor wafer 20 with a holding device 2 and so arranging the two wafers that joining faces 10b and 20b are opposite to each other (step 1), and a step of so applying magnetic fields with a coil 3 onto respective magnetic layers 10a and 20a in the package wafer 10 and the sensor wafer 20 that the two magnetic layers are magnetized in the same direction and bringing the respective joining faces 10b and 20b of the package wafer 10 and the sensor wafer 20 into contact with each other with an attraction force F working between the magnetized magnetic layers 10a and 20a (step 2).

Description

  The present invention relates to a wafer level package for manufacturing a wafer level package structure by bonding a sensor wafer having a plurality of sensor bodies each having a sensing unit and a package wafer having wirings electrically connected to the sensor bodies. The present invention relates to a method for manufacturing a structure.

  2. Description of the Related Art Conventionally, a method of manufacturing a single bonded substrate by bonding two semiconductor substrates using a magnet's attractive force is known. Specifically, one semiconductor substrate is attached to a magnetic board, an electromagnet is disposed on the back side of the other semiconductor substrate, and the outer surfaces of both semiconductor substrates are pressed and bonded together by the magnetic board and the attractive force of the electromagnet. Yes (Patent Document 1).

JP-A-6-84735 (14th to 15th paragraphs, FIG. 1).

  By the way, in a wafer level package structure formed by bonding a sensor wafer having a plurality of sensor bodies each having a sensing portion and a package wafer having wirings electrically connected to the sensor bodies, the outer surface of the package wafer is provided. Since electrical wiring, terminals, and the like are formed, pressing the outer surface of the package wafer may damage the electrical wiring, terminals, and the like.

  However, when the method for manufacturing a bonded substrate described above is applied to a method for manufacturing a wafer level package structure, the outer surface of the package wafer is pressed by the magnetic disk. Terminals may be damaged.

  Therefore, the present invention has been made to solve the above-described problems, and realizes a method for manufacturing a wafer level package structure in which electrical wiring and terminals formed on the outer surface of a package wafer are not likely to be damaged. With the goal.

  In order to achieve the above object, according to the first aspect of the present invention, a sensor wafer (20) in which a plurality of sensor bodies (21) having sensing portions (20g, 20h) are formed and electrically connected to each sensor body. In a method for manufacturing a wafer level package structure in which a wafer level package structure (30) is manufactured by joining a package wafer (10) on which wirings (10d, 10e) are formed, magnetic layers (10a, 20a ) And a magnetic field application device (3, 6, 7) for applying a magnetic field, and the package wafer and the sensor wafer are arranged so that the bonding surfaces (10b, 20b) face each other. The magnetization direction in each magnetic layer of the package wafer and the sensor wafer is the same as the first step A second step of applying a magnetic field (B) to each magnetic layer by a magnetic field application device and bringing the bonding surfaces of the package wafer and sensor wafer into contact with each other by an attractive force (F) acting between each magnetized magnetic layer; It has a technical feature.

When the invention according to claim 1 is carried out, the bonding surfaces of both wafers can be brought into contact with each other by an attractive force acting between the magnetic layers when a magnetic field is applied to each magnetic layer of the package wafer and the sensor wafer by the magnetic field application device. .
Therefore, it is not necessary to press the outer surface of the package wafer, so that there is no possibility that the electric wiring, terminals, etc. formed on the outer surface of the package wafer are damaged. In addition, since the outer surface of the sensor wafer is not pressed, even if the electric wiring or the terminal is formed on the outer surface of the sensor wafer, the electric wiring or the terminal is not likely to be damaged.

  According to a second aspect of the present invention, in the method for manufacturing a wafer level package structure (30) according to the first aspect, at least one of the package wafer (10) and the sensor wafer (20) has a central axis as a rotation center. The magnetic layers 10a and 20a of the package wafer and the sensor wafer are each divided into a plurality of regions, and the bonding surfaces 10b and 20b of the package wafer and the sensor wafer are relative to each other. It is a technical feature that it is formed at the same position on the wafer when facing.

  According to a third aspect of the present invention, in the method for manufacturing a wafer level package structure (30) according to the first or second aspect, at least one of the package wafer (10) and the sensor wafer (20) is a center thereof. Each of the magnetic layers 10a and 20a of the package wafer and the sensor wafer is formed in the same shape having a non-circular cross-section, and the package wafer and the sensor wafer are formed in the same shape. Further, it is a technical feature that the bonding surfaces 10b and 20b of the sensor wafer are formed at the same position on the wafer when they face each other.

If the invention which concerns on Claim 2 or Claim 3 is implemented, if the bonding surfaces of a package wafer and a sensor wafer will be made to oppose each other, each magnetic layer of both wafers will be attracted by the attractive force which acts between each magnetic layer of both wafers. Since at least one of the package wafer and the sensor wafer rotates so that the positions of the wafers face each other, the bonding position of both wafers can be automatically aligned.
Therefore, since an apparatus for adjusting the alignment is unnecessary, the manufacturing cost of the wafer level package structure can be reduced.

  In the invention according to claim 4, there are provided a sensor wafer (20) having a plurality of sensor bodies (21) each having a sensing portion (20g, 20h), and wirings (10d, 10e) electrically connected to the sensor bodies. In a wafer level package structure manufacturing method for manufacturing a wafer level package structure (30) by bonding the formed package wafer (10), a package wafer having a magnetic layer (10a) as an inner layer and a magnetic layer as an inner layer A sensor wafer having no layer, a magnetic field generator (8) for generating a magnetic field, and a magnetic field applying device (3, 6, 7) for applying the magnetic field (B) are prepared, and the package wafer and the sensor wafer are bonded to the bonding surface 10b. , 20b are arranged to face each other, and the sensor wafer exists between the package wafer and the magnetic field generator, A first step of disposing the package wafer such that the magnetic layer enters each magnetic field generated by the magnetic field generator and the magnetic field generator; and a magnetic pole appearing on the surface of the magnetic field generator facing the magnetic layer The magnetic layer is magnetized by applying a magnetic field to the magnetic layer so that a different magnetic pole appears on the surface of the magnetic layer facing the magnetic field generator, and the magnetized magnetic layer and the magnetic field generator And a second step of bringing the bonding surfaces of the package wafer and the sensor wafer into contact with each other by a suction force (F) acting between them.

When the invention according to claim 4 is carried out, even when the sensor wafer does not have a magnetic layer, it acts between the magnetic layer and the magnetic field generator when a magnetic field is applied to the magnetic layer of the package wafer by the magnetic field applying device. The bonding surfaces of both wafers can be brought into contact with each other by a suction force.
Therefore, it is not necessary to press the outer surface of the package wafer, so that there is no possibility that the electric wiring, terminals, etc. formed on the outer surface of the package wafer are damaged.

  According to a fifth aspect of the present invention, in the method of manufacturing a wafer level package structure (30) according to any one of the first to fourth aspects, in the second step, the magnetic field applying device (3) While adjusting the attractive force (F) by adjusting the strength of the magnetic field (B) applied to the magnetic layer (10a, 20a), the bonding surfaces (10b, 10b) of the package wafer (10) and the sensor wafer (20) are adjusted. 20b) A technical feature is that they are brought into contact with each other.

  If the invention according to claim 5 is implemented, the suction force acting between the bonding surfaces of the package wafer and the sensor wafer can be adjusted, so that the load on the bonding surface and the stress acting on the inside of both wafers are reduced. Therefore, both wafers can be prevented from being deformed.

  According to a sixth aspect of the present invention, in the method of manufacturing a wafer level package structure (30) according to any one of the first to fifth aspects, the magnetic field applying device (3, 6, 7) includes: A coil (3) for applying a magnetic field (B) to each of the magnetic layers (10a, 20a), and a current control device (6) for passing a current through the coil and controlling the magnitude of the flowing current. Is a technical feature.

  According to a seventh aspect of the present invention, in the method for manufacturing a wafer level package structure according to the sixth aspect of the present invention, the coil (3) has a central axis (3a) opposite to each other between the joint surfaces (10b, 20b). The package wafer (10) and the sensor wafer (20) are arranged so as to penetrate through the bonding surfaces and surround the package wafer and the sensor wafer, and the first step includes the package wafer. And the sensor wafer is a step of disposing the inside of the coil such that the bonding surfaces face each other and the central axis of the coil penetrates each bonding surface of the package wafer and the sensor wafer. .

  If the invention according to claim 6 or claim 7 is implemented, the suction force acting between the bonding surfaces of the package wafer and the sensor wafer can be adjusted by controlling the magnitude of the current flowing through the coil. By controlling the magnitude of the current flowing through the substrate with high accuracy, the pressing force on the bonding surface of the package wafer and the sensor wafer can be adjusted with high accuracy.

  In addition, the code | symbol in each said parenthesis shows the correspondence with the specific means as described in embodiment mentioned later.

(A) is a plan view of the package wafer, (b) is a side view of the package wafer, (c) is a plan view of the sensor wafer, and (d) is a side view of the sensor wafer. It is a longitudinal cross-sectional view of the cover and sensor main body which comprise an acceleration sensor. It is a longitudinal cross-sectional view of an acceleration sensor. It is a longitudinal cross-sectional view which shows the outline of the manufacturing apparatus used for the manufacturing method of the acceleration sensor which concerns on 1st Embodiment. It is explanatory drawing which shows the main electrical structures of a manufacturing apparatus. It is explanatory drawing of the magnetic field which acts on a package wafer and a sensor wafer. It is a longitudinal cross-sectional view which shows the outline of the manufacturing apparatus used for the manufacturing method of the acceleration sensor which concerns on 2nd Embodiment. It is a longitudinal cross-sectional view which shows the outline of the manufacturing apparatus used for the manufacturing method of the acceleration sensor which concerns on the example of a change of 2nd Embodiment. (A) is plane explanatory drawing of the package wafer used for the manufacturing method of the acceleration sensor which concerns on 3rd Embodiment, (b) is sectional drawing of a package wafer and a sensor wafer. It is plane explanatory drawing of the package wafer used for the manufacturing method of the acceleration sensor which concerns on the example of a change of 3rd Embodiment. It is plane explanatory drawing of the package wafer used for the manufacturing method of the acceleration sensor which concerns on the example of a change of 3rd Embodiment.

<First Embodiment>
A first embodiment according to the present invention will be described with reference to the drawings. In the following embodiments, a method for manufacturing an acceleration sensor having a wafer level package structure will be described as an example of a method for manufacturing a wafer level package structure according to the present invention. In the following description, when a matter common to both a package wafer and a sensor wafer is described, it may be abbreviated as a wafer.

[Acceleration sensor structure]
The main structure of the acceleration sensor will be described. 1A is a plan view of the package wafer, FIG. 1B is a side view of the package wafer, FIG. 1C is a plan view of the sensor wafer, and FIG. 1D is a side view of the sensor wafer. FIG. 2 is a vertical cross-sectional view of a lid and a sensor main body constituting the acceleration sensor. FIG. 3 is a longitudinal sectional view of the acceleration sensor.

  As shown in FIG. 1C, the sensor wafer 20 is formed with a plurality of sensor main bodies 21 constituting the acceleration sensor 30. As shown in FIG. 1A, the package wafer 10 is provided with a plurality of lids 11 for closing the openings of the sensor main body 21. After the package wafer 10 and the sensor wafer 20 are bonded, the bonded wafer is divided along a scribe line to obtain a plurality of acceleration sensors 30 having a wafer level package structure.

  As shown in FIGS. 2 and 3, the acceleration sensor 30 includes a sensor main body 21 and a lid 11 for closing the opening of the sensor main body 21. The sensor body 21 is formed by processing an SOI (silicon on insulator) substrate formed by forming a silicon layer 20e on the surface of the silicon layer 20c via a silicon oxide film 20d.

  In the recesses 20f formed on the surface of the silicon layer 20e, movable electrodes 20g and fixed electrodes 20h formed by etching are alternately formed in a comb shape. The movable electrode 20g and the fixed electrode 20h constitute a sensing unit. A joining surface 20 b for joining the lid 11 is formed on the surface of the sensor body 21. A magnetic layer 20a is formed in the inner layer of the silicon layer 20c in parallel with the bonding surface 20b.

  The lid 11 is formed by processing the silicon substrate 10c. A through-electrode 10d that penetrates the substrate surface in the vertical direction is formed in the silicon substrate 10c, and a terminal 10e that is electrically connected to the through-electrode 10d is formed at the upper end of the through-electrode 10d. A joining surface 10 b for joining the sensor body 21 is formed on the back surface of the lid 11. A magnetic layer 10a is formed on the inner layer of the silicon substrate 10c in parallel with the bonding surface 10b.

  In this embodiment, each magnetic layer 10a, 20a is formed of a ferromagnetic material such as NiFe alloy, Co, CoNiFe alloy, CoFe alloy, CoNi alloy. Each magnetic layer 10a, 20a is formed by sputtering.

  A signal output from the sensor body 21 is taken out from the pad 20 i formed on the bonding surface 20 b of the sensor body 21 through the through electrode 10 d and the terminal 10 e formed on the lid 11. The operation power of the sensor body 21 is supplied from the terminal 10e of the lid 11 and the through electrode 10d through a pad 20i formed on the bonding surface 20b of the sensor body 21.

When the bonding surface 10b of the package wafer 10 and the bonding surface 20b of the sensor wafer 20 are bonded to each other, the through electrode 10d of each lid 11 and the pad 20i formed on the surface of each bonded sensor body 21 are electrically connected. Connected.
When acceleration is applied to the sensor body 21, each movable electrode 20g is displaced, the capacitance between the movable electrode 20g and the fixed electrode 20h changes, and the output voltage of the sensor body 21 changes.

[Production equipment structure]
The main structure of the manufacturing apparatus will be described. FIG. 4 is a longitudinal sectional view schematically showing a manufacturing apparatus used in the method for manufacturing the acceleration sensor according to the first embodiment. FIG. 5 is an explanatory diagram showing the main electrical configuration of the manufacturing apparatus. FIG. 6 is an explanatory diagram of magnetic fields acting on the package wafer and the sensor wafer.

  As shown in FIG. 4, the manufacturing apparatus 1 includes a base 5, a coil 3 disposed on the base 5, a holding device 2 that holds the back surface of the sensor wafer 20, and a holding that holds the surface of the package wafer 10. Device 4. The holding device 2 can be raised and lowered in the direction indicated by the arrow D1, and the holding device 4 can be raised and lowered in the direction indicated by the arrow D2.

  The package wafer 10 and the sensor wafer 20 are arranged with the bonding surfaces 10b and 20b facing each other. The coil 3 is formed in such a size as to surround each peripheral surface of the package wafer 10 and the sensor wafer 20 arranged as described above. The holding devices 2 and 4 hold the wafers so that the bonding surfaces 10 b and 20 b face each other inside the coil 3. As shown in FIG. 6A, the package wafer 10 and the sensor wafer 20 are arranged inside the coil 3 so that the central axis 3a of the coil 3 penetrates the magnetic layers 10a and 20a of each wafer.

  In this embodiment, as shown in the drawing, both wafers are arranged so that the magnetic field B penetrates through the magnetic layers 10a and 20a from top to bottom. The package wafer 10 and the sensor wafer 20 are arranged inside the coil 3 so that the distribution of the magnetic field B generated from the coil 3 and penetrating the magnetic layers 10a and 20a is uniform in each magnetic layer. As the holding devices 2 and 4, for example, a known wafer chuck table that sucks and holds a wafer can be used.

  When the package wafer 10 and the sensor wafer 20 are arranged inside the coil 3 with the joint surfaces 10b and 20b facing each other and a current is passed through the coil 3, a magnetic field B is generated around the coil 3 as shown in FIG. The magnetic field B penetrates both wafers from top to bottom. Thereby, as shown in FIG. 6B, an N pole appears on the surface of the magnetic layer 10a of the package wafer 10, and an S pole appears on the back surface. Further, the N pole appears on the surface of the magnetic layer 20a of the sensor wafer 20, and the S pole appears on the back surface. That is, different magnetic poles appear on the opposing surfaces of the magnetic layers 10a and 20a.

  Therefore, since the attractive force F generated between the different magnetic poles acts between the magnetic layers 10a and 20a, the bonding surface 10b of the package wafer 10 and the bonding surface 20b of the sensor wafer 20 are mutually connected using the attractive force F. Can be contacted.

  As shown in FIG. 5, the manufacturing apparatus 1 includes a current control device 6 that controls the magnitude of a current flowing through the coil 3, and a power source 7 that supplies power to the current control device 6. When the current control device 6 decreases the current flowing through the coil 3, the strength of the magnetic field B generated from the coil 3 decreases. When the current flowing through the coil 3 increases, the strength of the magnetic field B generated from the coil 3 increases.

  The current control device 6 is synchronized with the control device that controls the holding devices 2 and 4, the holding devices 2 and 4 reach a specific position, and the bonding surface 10 b of the package wafer 10 and the bonding surface 20 b of the sensor wafer 20 When the distance reaches a specific distance, the current flowing through the coil 3 is increased and the strength of the magnetic field B is increased. At this time, the holding device 2 loses the holding force for holding the sensor wafer 20, so that the sensor wafer 20 is attracted to the package wafer 10 by the suction force F. For example, when the holding device 2 is a wafer chuck table, the negative pressure state of the suction surface of the sensor wafer 20 may be released.

[Production method]
A method for manufacturing the acceleration sensor will be described.
The package wafer 10 is held by the holding device 4 and is arranged in the upper part of the coil 3 so that the bonding surface 10b faces downward as shown in FIG. Subsequently, the sensor wafer 20 is held by the holding device 2 and disposed below the inside of the coil 3 so that the bonding surface 20b faces the bonding surface 10b of the package wafer 10 as shown in FIG. That is, the package wafer 10 and the sensor wafer 20 are arranged so that the bonding surfaces 10b and 20b face each other (first step). At this time, the holding device 2 releases the force holding the sensor wafer 20. Note that the sensor wafer 20 may be disposed below the inside of the coil 3 first.

  Subsequently, a current is supplied to the coil 3 by the current control device 6 to generate a magnetic field B in the coil 3. Subsequently, the holding device 2 is gradually raised to bring the sensor wafer 20 close to the package wafer 10, and the bonding surface 20 b of the sensor wafer 20 is attracted to the bonding surface 10 b of the package wafer 10 by the suction force F. That is, a magnetic field is applied to each magnetic layer 10a, 20a by the coil 3 so that the magnetization directions in the respective magnetic layers 10a, 20a of the package wafer 10 and the sensor wafer 20 are the same, and the magnetized magnetic layers 10a, 20a are interposed. The bonding surfaces 10b and 20b of the package wafer 10 and the sensor wafer 20 are brought into contact with each other by the acting suction force F (second process).

  At this time, since the package wafer 10 is only held by the holding device 4 and is not pressed downward, there is no possibility that the electrical wiring, the terminals 10e, and the like formed on the surface of the package wafer 10 are damaged. Further, the sensor wafer 20 is not pressed from below by the holding device 2 but is automatically attracted to the package wafer 10 only by the attractive force F acting between the magnetic layers 10a and 20a. Even if wiring, terminals, etc. are formed, there is no possibility that they will be damaged.

  When the distance between the joining surfaces 10b and 20b reaches a specific distance, the raising of the holding device 2 is interrupted, the current flowing through the coil 3 is gradually increased, and the strength of the magnetic field B is gradually increased. The bonding surface 20 b of the sensor wafer 20 may be attracted to the bonding surface 10 b of the package wafer 10 by the force F. Further, the holding device 4 may be lowered, and the lowering of the holding device 4 and the raising of the holding device 2 may be performed simultaneously.

[Effect of the first embodiment]
(1) If the method for manufacturing the acceleration sensor 30 according to the first embodiment described above is performed, the magnetic layer B when the magnetic field B is applied to the magnetic layers 10a and 20a of the package wafer 10 and the sensor wafer 20 by the coil 3 is applied. The bonding surfaces 10b and 20b of both wafers can be brought into contact with each other by the suction force F.
Therefore, since it is not necessary to press the surface of the package wafer 10, there is no possibility that the electric wiring, the terminals 10e, etc. formed on the surface of the package wafer 10 are damaged. Further, since the bottom surface of the sensor wafer 20 is not pressed, even if electrical wiring, terminals, or the like are formed on the bottom surface of the sensor wafer 20, there is no possibility that the electrical wiring, terminals, etc. are damaged.

(2) Further, by controlling the magnitude of the current flowing through the coil 3 by the current control device 6, the attractive force F acting between the bonding surfaces 10 b and 20 b of the package wafer 10 and the sensor wafer 20 can be adjusted.
Therefore, since the load applied to the bonding surfaces 10b and 20b and the stress acting on the inside of both wafers can be adjusted to be small, both the wafers can be prevented from being deformed.
(3) Furthermore, if the magnitude | size of the electric current sent through the coil 3 is controlled with high precision, the pressing force in the joint surfaces 10b and 20b can be adjusted with high precision.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a longitudinal sectional view showing an outline of a manufacturing apparatus used in the method for manufacturing an acceleration sensor according to the second embodiment. In addition, the same code | symbol is used about the same structure as 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIG. 7, an electromagnet 8 is disposed inside a base 5 that constitutes the manufacturing apparatus 1. The portion where the electromagnet 8 generates a magnetic field is approximately the same area as the sensor wafer 20 and is disposed to face the back surface of the sensor wafer 20. The electromagnet 8 is electrically connected to a control device (not shown) that adjusts the strength of the magnetic field generated from the electromagnet 8. A sensor wafer 20 is placed on the base 5. A magnetic layer 10 a is formed on the inner layer of the package wafer 10, but no magnetic layer is formed on the sensor wafer 20.

  The sensor wafer 20 is placed on the surface of the base 5 inside the coil 3 by the holding device 4. Next, the package wafer 10 is arranged inside the coil 3 so that the bonding surfaces 10 b and 20 b face each other by the holding device 4. At this time, the sensor wafer 20 exists between the package wafer 10 and the electromagnet 8, and the package wafer 10 is arranged so that the magnetic layer 10 a of the package wafer 10 enters each magnetic field generated by the coil 3 and the electromagnet 8. To do.

  That is, the package wafer 10 and the sensor wafer 20 are arranged so that the bonding surfaces 10b and 20b face each other, the sensor wafer 20 exists between the package wafer 10 and the electromagnet 8, and the coil 3 and the electromagnet 8 The package wafer 10 is arranged so that the magnetic layer 10a of the package wafer 10 enters each generated magnetic field (first step).

  Next, a current is passed through the coil 3 and the electromagnet 8. At this time, the magnetic field B is applied to the magnetic layer 10a by the coil 3 so that a magnetic pole different from the magnetic pole appearing on the surface of the electromagnet 8 facing the magnetic layer 10a of the package wafer 10 appears on the surface of the magnetic layer 10a facing the electromagnet 8. To magnetize. Then, the bonding surface 20 b of the sensor wafer 20 is attracted to the bonding surface 10 b of the package wafer 10 by the attractive force F acting between the magnetized magnetic layer 10 a and the electromagnet 8.

  That is, a magnetic field is applied to the magnetic layer 10a by the coil 3 so that a magnetic pole different from the magnetic pole appearing on the surface of the electromagnet 8 facing the magnetic layer 10a appears on the surface of the magnetic layer 10a facing the electromagnet 8. Then, the bonding surfaces 10b and 20b of the package wafer 10 and the sensor wafer 20 are brought into contact with each other by the attractive force F acting between the magnetized magnetic layer 10a and the electromagnet 8 (second step). Note that the attractive force F can be adjusted by controlling the magnitude of the current flowing through at least one of the coil 3 and the electromagnet 8. Further, a permanent magnet can be used in place of the electromagnet 8.

As described above, when the acceleration sensor manufacturing method according to the second embodiment is performed, a magnetic field is applied to the magnetic layer 10a of the package wafer 10 by the coil 3 even when the sensor wafer 20 does not have a magnetic layer. The bonding surfaces 10b and 20b of both wafers can be brought into contact with each other by the attractive force F acting between the magnetic layer 10a and the electromagnet 8.
Therefore, since it is not necessary to press the surface of the package wafer 10, there is no possibility that the electric wiring, the terminals 10e, etc. formed on the surface of the package wafer 10 are damaged.

<Example of change>
A modification of the second embodiment will be described with reference to the drawings. FIG. 8 is a longitudinal sectional view showing an outline of a manufacturing apparatus used in the method of manufacturing an acceleration sensor according to this modification. As shown in FIG. 8, a plurality of electromagnets 8 are arranged inside the base 5 constituting the manufacturing apparatus 1. Each electromagnet 8 is electrically connected to a control device (not shown), and is configured so that the strength of the magnetic field generated by each electromagnet 8 can be individually adjusted by the control device.

In other words, by individually adjusting the strength of the magnetic field generated by each electromagnet 8, the load acting on the contact portion of the package wafer 10 and the sensor wafer 20 and the stress acting on the inside of both wafers are divided into a plurality of contact regions and adjusted. can do.
The arrangement pattern of each electromagnet 8 is not limited to a linear, grid, or circular arrangement pattern, and can be set according to the shape of the magnetic layer 10 a of the package wafer 10. A permanent magnet can be used instead of each electromagnet 8.

<Third Embodiment>
Next, a third embodiment of the invention will be described with reference to the drawings. FIG. 9A is an explanatory plan view of a package wafer used in the acceleration sensor manufacturing method according to the third embodiment, and FIG. 9B is a cross-sectional view of the package wafer and the sensor wafer. In addition, the same code | symbol is used about the same structure as 1st Embodiment, and the description is abbreviate | omitted.

  Each of the magnetic layers 10a and 20a of the package wafer 10 and the sensor wafer 20 is divided into a plurality of regions, and the same on the wafer when the bonding surfaces 10b and 20b of the package wafer 10 and the sensor wafer 20 face each other. Formed in position. In this embodiment, each of the magnetic layers 10a and 20a is divided into four regions, and each magnetic layer is formed in a + shape in cross section.

  When the manufacturing apparatus 1 shown in FIG. 4 is used and the package wafer 10 and the sensor wafer 20 are disposed with the bonding surfaces 10b and 20b facing each other as shown in FIG. 9B, the magnetic layers 10a facing each other. , 20a is slightly shifted. At this time, when the holding force of the holding device 2 is released, the sensor wafer 20 rotates to the position where the magnetic layers 10a and 20a face each other by the attractive force F acting between the magnetic layers 10a and 20a, and the arrangement position The deviation is corrected. That is, it is possible to automatically align the bonding positions of both wafers.

As described above, if the method for manufacturing the acceleration sensor according to the third embodiment is implemented, an apparatus for adjusting the alignment of the bonding positions of both wafers is not necessary, so that the manufacturing cost of the acceleration sensor can be reduced. it can.
Further, the holding device 2 itself may be configured to be rotatable, and the holding device 2 may be rotated by the suction force F while holding the sensor wafer 20. Further, the holding device 4 may be configured to be rotatable, and the holding device 4 may be rotated by the suction force F while holding the package wafer 10. Furthermore, the cross-sectional shape of each of the magnetic layers 10a and 20a may be a shape other than the + type such as a circle.

<Example of change>
A modification of the third embodiment will be described with reference to the drawings. 10 and 11 are plan explanatory views of a package wafer used in the method of manufacturing an acceleration sensor according to this modification. As shown in FIG. 10, the magnetic layer 10a of the package wafer 10 is formed in a strip shape extending in all directions from the center of the wafer, and is formed so that the entire cross-sectional shape is a + type, and the magnetic layer 20a of the sensor wafer 20 is also formed. You may form in the same shape. Further, as shown in FIG. 11, the magnetic layer 10a may be formed so that the cross-sectional shape is a lattice shape, and the magnetic layer 20a of the sensor wafer 20 may be formed in the same shape.

  That is, the magnetic layers 10a and 20a of the package wafer 10 and the sensor wafer 20 are formed to have the same non-circular cross-sectional shape, and the bonding surfaces 10b and 20b of the package wafer 10 and the sensor wafer 20 face each other. Formed at the same position on the wafer. In the case of these configurations, as in the third embodiment described above, alignment of the bonding positions of both wafers can be automatically performed.

  In each of the above-described embodiments, the wafer level package structure manufacturing method according to the present invention has been described by taking the wafer level package structure acceleration sensor as an example. However, the wafer level package structure manufacturing method according to the present invention is described below. The present invention can also be applied to sensors such as a wafer level package structure collision sensor, yaw rate sensor, and pressure sensor. Further, it can be applied to a wafer level package structure other than the sensor.

1 .... Manufacturing equipment, 2 .... Holding device, 3 .... Coil (magnetic field applying device), 4 .... Holding device,
10. Package wafer, 10a, Magnetic layer, 10b, Bonding surface,
20 .. Sensor wafer, 20a ... Magnetic layer, 20b ... Bonding surface,
30. ・ Acceleration sensor (wafer level package structure).

Claims (7)

Manufacturing a wafer level package structure by bonding a sensor wafer having a plurality of sensor bodies having a sensing unit and a package wafer having wirings electrically connected to each sensor body to manufacture a wafer level package structure In the method
A package wafer and a sensor wafer each having a magnetic layer as an inner layer, and a magnetic field application device for applying a magnetic field are prepared.
A first step of arranging the package wafer and the sensor wafer so that the bonding surfaces face each other;
A magnetic field is applied to each magnetic layer by the magnetic field application device so that the magnetization directions of the magnetic layers of the package wafer and the sensor wafer are the same, and an attractive force acting between the magnetized magnetic layers causes the package wafer and the sensor wafer to A second step of bringing the joint surfaces into contact with each other;
A method for producing a wafer level package structure, comprising: At least one of the package wafer and the sensor wafer is disposed so as to be rotatable about the center axis thereof,
Each of the magnetic layers of the package wafer and the sensor wafer is divided into a plurality of regions, and is formed at the same position on the wafer when the bonding surfaces of the package wafer and the sensor wafer face each other. The method for manufacturing a wafer level package structure according to claim 1, wherein: At least one of the package wafer and the sensor wafer is disposed so as to be rotatable about the center axis thereof,
Each magnetic layer of the package wafer and the sensor wafer is formed in the same non-circular cross-sectional shape, and the same position on the wafer when the bonding surfaces of the package wafer and the sensor wafer face each other. The method of manufacturing a wafer level package structure according to claim 1 or 2, wherein the wafer level package structure is formed as follows. Manufacturing a wafer level package structure by bonding a sensor wafer having a plurality of sensor bodies having a sensing unit and a package wafer having wirings electrically connected to each sensor body to manufacture a wafer level package structure In the method
A package wafer having a magnetic layer as an inner layer, a sensor wafer not having a magnetic layer as an inner layer, a magnetic field generator for generating a magnetic field, and a magnetic field applying device for applying a magnetic field are prepared.
The package wafer and the sensor wafer are arranged so that the bonding surfaces thereof face each other, the sensor wafer exists between the package wafer and the magnetic field generator, and the magnetic field generator and the magnetic field generator are generated. A first step of placing the package wafer such that the magnetic layer enters each magnetic field;
A magnetic field is applied to the magnetic layer by the magnetic field application device so that a magnetic pole different from the magnetic pole appearing on the surface of the magnetic field generator facing the magnetic layer appears on the surface of the magnetic layer facing the magnetic field generator. A second step of bringing the bonding surfaces of the package wafer and the sensor wafer into contact with each other by an attractive force acting between the magnetized magnetic layer and the magnetic field generator;
A method for producing a wafer level package structure, comprising:   In the second step, the bonding surfaces of the package wafer and the sensor wafer are brought into contact with each other while adjusting the attractive force by adjusting the strength of the magnetic field applied to the magnetic layer by the magnetic field application device. The manufacturing method of the wafer level package structure as described in any one of Claim 1 thru | or 4. The magnetic field application device includes:
A coil for applying a magnetic field to the magnetic layer;
6. A wafer level package structure manufacturing method according to claim 1, further comprising: a current control device configured to flow a current to the coil and to control a magnitude of the flowing current. Method. The coil is
The central axis is configured to pass through each joint surface of the package wafer and the sensor wafer arranged so that the joint surfaces face each other, and surround the package wafer and the sensor wafer,
The first step includes
It is a step of arranging the package wafer and the sensor wafer inside the coil so that the bonding surfaces face each other and the central axis of the coil penetrates each bonding surface of the package wafer and the sensor wafer. A method for manufacturing a wafer level package structure according to claim 6.

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