JP2014069217A - Joint method, joint body and vibration actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint method capable of a metallic bond with low surface accuracy.SOLUTION: The joint method of the present invention is a joint method comprising a step of metal-plating a surface of first members 10, 110A and 110B and a step of joining the metal-plated first members 10, 110A and 110B and second members 20, 120A and 120B by the metallic bond. In the joint method, flatness of a joint surface of the second members 20, 120A and 120B is a PV value or less of a joint surface of the metal-plated first members 10, 110A and 110B.

Description

  The present invention relates to a joining method, a joined body, and a vibration actuator.

  Conventionally, vacuum bonding is performed in semiconductor packaging. However, in order to join metals together by a vacuum joining method, the surface accuracy (surface roughness, PV value) of the joint surface must be several tens of nm or less (see Patent Document 1).

JP 2004-327718 A

However, it is not easy to reduce the surface accuracy of the joint surface to several tens of nm or less, and the manufacturing cost is also high.
An object of the present invention is to provide a joining method capable of metal bonding with low surface accuracy, a joined body joined by the joining method, and a vibration actuator including the joined body.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.

Invention of Claim 1 is a joining method provided with the process of metal-plating the surface of a 1st member, and the process of joining the said 1st member and 2nd member by which metal plating was carried out by metal bonding, In the joining method, the flatness of the joining surface of the second member is equal to or less than the PV value of the joining surface of the metal-plated first member.
Invention of Claim 2 is a joining method of Claim 1, Comprising: The joining by the said metal bond is joining by the surface activation method, It is a joining method characterized by the above-mentioned.
A third aspect of the present invention is the joining method according to the first or second aspect, wherein the joining by metal bonding is vacuum joining.
The invention according to claim 4 is the joining method according to any one of claims 1 to 3, wherein the joining by the metal bond is a room temperature joining.
Invention of Claim 5 is the joining method of any one of Claim 1 to 4, Comprising: PV value of the joint surface of a said 1st member is the particle | grains of the largest particle which exists in this joint surface It is a joining method characterized by having a diameter.
A sixth aspect of the present invention is the joining method according to any one of the first to fifth aspects, wherein the metal plating is copper plating.
According to a seventh aspect of the present invention, the first member whose surface is metal-plated, and the flatness of the joint surface with respect to the surface of the first member are equal to or less than the PV value of the joint surface of the first member. A joined body in which the first member and the second member are metal-bonded.
According to an eighth aspect of the present invention, there is provided a driving member manufactured by metal-bonding an electromechanical transducer to a first member whose surface is metal-plated, a pressure contact with the driving member, and the electric machine. A vibration member having a relative movement member that moves relative to the driving body by vibration of the conversion element, wherein the flatness of the bonding surface of the electromechanical conversion element is equal to the bonding surface of the electromechanical conversion element. It is a vibration actuator which is below the PV value.
Note that the configuration described with reference numerals may be modified as appropriate, and at least a part of the configuration may be replaced with another component.

  According to the present invention, it is possible to provide a bonding method capable of metal bonding with low surface accuracy, a bonded body bonded by the bonding method, and a vibration actuator including the bonded body.

It is a figure which shows the joining method of 1st Embodiment of this invention, (A) is the schematic diagram which cut | disconnected the 1st member in the direction perpendicular | vertical to the surface, (B) is the 1st joining surface and the 2nd joining surface. The figure which showed the state made to contact lightly, (C) is a figure which shows the conjugate | zygote of a 1st joining surface and a 2nd joining surface. It is a flowchart which shows the manufacturing method of a conjugate | zygote. It is the electron micrograph which image | photographed the 1st joint surface in a 1st example from the upper surface. It is a photograph which shows the joint surface of the 1st member in a 2nd example, (A) is the schematic diagram cut | disconnected in the direction perpendicular | vertical to the 1st joint surface and the surface, (B) is an upper surface of the 1st joint surface. It is the electron micrograph which was image | photographed from. It is a photograph which shows the joint surface of the 1st member in a 3rd example, (A) is the schematic diagram cut | disconnected in the direction perpendicular | vertical to a 1st joint surface and a surface, (B) is a 1st joint surface on an upper surface. It is the electron micrograph which was image | photographed from. The vertical axis represents the thickness of the electrolytic plating, and the horizontal axis represents the position in the width direction of the first joint surface. It is a front view of a vibration actuator. It is a conceptual diagram of a lens barrel provided with a vibration actuator and a camera equipped with the lens barrel.

(First embodiment)
FIG. 1 is a view for explaining a joining method according to the first embodiment of the present invention. Although the joining method will be described later, FIG. 1C is a diagram showing the joined body 1 joined by the joining method of the present embodiment. As shown in FIG. 1 (C), the joined body 1 has a first member 10 having a metal plating 11 applied to the surface thereof to form a joined surface (first joined surface 12), and a joined surface of the second member 20. (Second bonding surface 22) and vacuum bonded at room temperature.

The first member 10 is a thin plate member and is provided with a metal plating 11. The material of the metal plating 11 is copper (Cu), gold (Au), tin (Sn) or the like, and is matte plating.
On the other hand, the second member 20 may be a metal whose base material is a metal and the second joining surface 22 may be a metal surface of the base material, or whose base material is other than a metal and whose surface is subjected to metal plating. It is also possible that the base material is a metal and the surface is further plated with metal.
In the present embodiment, the second joint surface 22 has a Vickers hardness Hv greater (hard) than the first joint surface 12 (surface after plating).

  Moreover, the 1st joining surface 12 of the 1st member 10 and the 2nd joining surface 22 of the 2nd member 20 are joined by normal temperature vacuum bonding. As the room-temperature vacuum bonding, surface activated room-temperature vacuum bonding (SAB) is used.

FIG. 2 is a flowchart showing a method for manufacturing the joined body 1.
First, the first member 10 is washed to remove dust from the first joint surface 12 (dust removal, step S1).
Next, the 1st member 10 is put into a metal plating tank, and the 1st joint surface 12 is metal-plated (plating process, step S2). In this embodiment, the material of the metal plating 11 is copper (Cu), and the first mating surface 12 is subjected to Cu matte plating. Moreover, electroless plating is used for Cu matte plating. The reason is that, compared with electrolytic plating, electroless plating has an almost flat edge on the plated surface and is easy to maintain flatness.

The thickness of the metal plating 11 is preferably 0.1 μm to 10 μm. The PV (Peak-Valley) value of the first joint surface 12 on which the metal plating 11 is performed is larger than the flatness h of the second joint surface 22 (the first joint surface is flatter than the second joint surface). That is, the flatness h of the second bonding surface 22 ≦ the PV value of the metal plating 11 of the first bonding surface 12.
Here, the flatness of the second member 20 is measured by a flatness measuring device of a laser beam oblique incidence interferometer.
Moreover, PV value is defined as follows from the photograph of the 1st joint surface image | photographed with the electron microscope. Here, the state of the first joint surface is not uniform, and various photographs (first to third examples) are taken, but are handled as follows according to the photographs.

(First example)
FIG. 3 is an electron micrograph of the first joint surface 12 taken from the upper surface in the first example in which the metal plating 11 is deposited on the surface of the first member 10. FIG. 1A is a schematic cross-sectional view of the first member 10 cut in a direction perpendicular to the surface.
As shown in the photograph of FIG. 3, Cu is deposited in a granular form on the surface of the first member 10 by Cu matte plating, and a plurality of particles are observed when the first bonding surface 12 is viewed from above.

In such a case, the PV value is defined as follows in the present embodiment.
First, from the photograph in FIG. 3, the maximum diameter of the particles present in the photograph is measured. If the particles are not circular on the photograph, the maximum width of the particles present on the photograph is the maximum diameter. Then, assuming that there is a height difference corresponding to the maximum diameter also in the thickness direction of the metal plating 11, this maximum diameter is set as a PV value in the first joint surface 12.
The particle size of the Cu matte plating particles is generally on the order of several μm. And 0.1 micrometers or more are preferable in both a particle size and a height direction. This is because if it is smaller than 0.1 μm, it is not easy to obtain accuracy and manufacturing cost is increased.

  Moreover, it is preferable that the surface plated with the metal plating 11 is not oxidized. For this reason, the surface of the metal plating 11 is subjected to a chemical bonding surface oxide film removal process (oxide film removal, step S3). This oxide film removing step is preferably performed immediately before bonding.

  Then, the first member 10 and the second member 20 are bonded at room temperature under vacuum (bonding, step S4). At this time, the room temperature vacuum bonding is performed in a state where the pressure F is applied in a direction perpendicular to the bonding surface.

  Conventionally, the surface accuracy required for room temperature vacuum bonding is several tens of nm in terms of surface accuracy of the bonding surface, and if it is more than that (when surface accuracy is poor), bonding becomes difficult. However, according to this embodiment, although the PV value of the first bonding surface 12 is about several μm, the metal adheres by vacuum bonding, and good adhesion can be obtained.

The reason is considered as follows. According to the present embodiment, the second bonding surface 22 is harder than the first bonding surface 12 (the Cu plating 11 deposited on the surface of the first member 10 is softer than the second bonding surface 22 of the second member 20).
FIG. 1B is a view showing a state in which the first joint surface 12 and the second joint surface 22 are lightly brought into contact with each other. Here, as shown in FIG. 1B, the second bonding surface 22 is not completely flat but has a flatness h = 1 μm.
On the other hand, the first bonding surface 12 is not completely flat, and the PV value is 1 μm. Therefore, as shown in FIG. 1B, when the first joint surface 12 and the second joint surface 22 are lightly brought into contact (before the pressure F is applied), a void S is formed at the joint interface.

In this state, when pressure F is applied between the first joint surface 12 and the second joint surface 22 in a direction approaching each other (FIG. 3C), it is generated by the Cu plating 11 that is softer than the first joint surface 12. The formed particles are crushed to fill the voids S.
According to the present embodiment, since the flatness h of the second member 20 is equal to or less than the PV value of the metal plating 11 of the first member 10, the gap is filled before all the particles are crushed (FIG. 3C), This is because each other fits in and completes.

  Conversely, if the flatness h of the second member 20> the PV value of the metal plating 11 of the first member 10, it is considered that even if all the particles are crushed, the gap is not completely filled and the degree of adhesion is lowered.

(Second example)
FIG. 4 is a photograph showing the joining surface 12 of the first member 10 in the second example, and FIG. 4A is a schematic view cut in a direction perpendicular to the first joining surface 12 and the surface. These are the electron micrographs which photoed the 1st joined surface 12 from the upper surface.
As illustrated, a large lump 11A of Cu is formed on the surface of the first member 10, and particles 11B as in the first example are deposited thereon.

Also in this case, as in the first example, the PV value is first determined from the photograph by measuring the maximum diameter of the particles present in the photograph. When the particle is not circular on the photograph, the maximum width of the particle on the photograph is the maximum diameter. Then, assuming that there is a height difference corresponding to this maximum diameter also in the thickness direction of the plating, this maximum diameter is defined as the PV value at the first joint surface.
In this case, however, the particles are deposited on the large mass 11A. When the surface accuracy PV0 of the surface of the lump 11A is large, unlike the above-described first example, the particles 11B are consumed to cancel out the surface waviness, and there is a possibility that the entire space cannot be filled. Therefore. In such a case, the swell formed by the mass 11A is preferably about 1/10.

(Third example)
It is a photograph which shows the joint surface of the 1st member 10 in the 3rd example, (A) is a mimetic diagram cut in the direction perpendicular to the 1st joint surface 12 and the surface, and (B) is the 1st It is the electron microscope photograph which image | photographed the joint surface 12 from the upper surface.
In the third example, the first bonding surface 12 is not granular but Cu is deposited on the whole to form ridges. In this case as well, as in the first example, the maximum diameter of the raised object when viewed from the upper surface is measured, and this is taken as the PV value at this joint surface.

(Deformation)
In the present embodiment, electroless plating is used as described above, but the present invention is not limited to this, and electrolytic plating may be used. In FIG. 6, the vertical axis represents the thickness of the electrolytic plating, and the horizontal axis represents the position of the first bonding surface 12 in the width direction.
As shown in the figure, in the case of electrolytic plating, the electrolytic plating is thicker at the edge portion of the first joint surface 12. That is, the edge is raised. If it joins with the 2nd joining surface 22 with the edge rising, the space | gap S will become large and vacuum joining will become difficult.
In this case, the first member 10 as the base material is chamfered in advance to cancel the rising of the edge portion, thereby enabling vacuum bonding.

(Second Embodiment)
In 2nd Embodiment, the case where the joining method of this invention is used for joining between the members used for a vibration actuator is demonstrated.
FIG. 7 is a front view of the vibration actuator 100. FIG. 8 is a conceptual diagram of a lens barrel 300 including the vibration actuator 100 and a camera 200 to which the lens barrel 300 is attached.
As shown in FIG. 1, the vibration actuator 100 of this embodiment includes a base member 150 and a rotor 160 placed on the base member 150.

The base member 150 is formed in a hollow cylindrical shape, and is provided with six holding recesses 170 in the circumferential direction for accommodating a drive mechanism 101 (joined body) described later.
The rotor 160 is rotatable with respect to the base member 150, and a gear 125 for outputting a rotational force is formed on the outer peripheral surface thereof. The rotor 160 is supported by the drive mechanism 101.

The drive mechanisms 101 are respectively held in the holding recesses 170.
One drive mechanism 101 is disposed between a lifter (first member) 110A for lifting the rotor 160, a slider (first member) 110B that moves the rotor 160 in the rotational direction, and the lifter 110A and the base member 150. The lift piezoelectric body 120A (second member) is provided, and the slide piezoelectric body 120B (second member) disposed between the lifter 110A and the slider 110B.

The lifter 110 </ b> A is accommodated in the holding recess 170 in the base member 150.
The lift piezoelectric body 120A and the slide piezoelectric body 120B are rectangular plate materials made of lead zirconate titanate (PZT), for example, and have a piezoelectric effect.
The lift piezoelectric body 120 </ b> A is disposed between the outer surface of the lifter 110 </ b> A and the inner wall surface of the holding recess 170.
The slider 110B is disposed on the upper surface of the lifter 110A via the slide piezoelectric body 120B.

  A drive voltage is applied to the lift piezoelectric body 120A and the slide piezoelectric body 120B from a drive circuit controlled by a control device (not shown). The lift piezoelectric body 120A vibrates by this driving voltage to drive the lifter 110A up and down, and the slide piezoelectric body 120B vibrates to drive the slider 110B in the circumferential direction R.

  In the six drive mechanisms 101, every other drive mechanism 101 operates in the same phase as the same group and in a different phase from the other groups. As a result, for each drive mechanism 101 in the same group, the rotor 160 is alternately supported in the circumferential direction R and driven relative to the base member 150, and the rotor 160 is continuously rotated in the circumferential direction R.

  FIG. 8 is a conceptual diagram of the camera 200 to which the lens barrel 300 including the vibration actuator 100 is attached. In the vibration actuator 100, the gear 125 of the rotor 160 is disposed in mesh with a gear formed on the outer periphery of the cam cylinder 302, and rotates the cam cylinder 302. Thereby, the focusing lens 301 is driven during the focusing operation of the camera 200.

In the second embodiment, the lifter 110A and the lift piezoelectric body 120A are bonded by surface activated room temperature vacuum bonding as in the first embodiment, and are performed based on the flowchart of FIG.
That is, first, the lifter 110A is washed to remove dust (S1).

Next, the lifter 110A is placed in a metal plating tank, and metal plating is performed on the joint surface to which the lift piezoelectric body 120A of the lifter 110A is joined (S2).
At this time, as in the first embodiment, the flatness of the lift piezoelectric body ≦ the PV value of the metal plating of the lifter 110A.

  On the other hand, the lift piezoelectric body 120A is also cleaned to remove dust, and a surface activation process is performed to remove the oxide film on the surface by sputtering the joint surface of the lift piezoelectric body 120A (S3).

  Next, in the lifter 110A and the lift piezoelectric body 120A, the metal plated portion and the surface activated portion are joined (S4).

  In addition, although the joining of the lifter 110A and the lift piezoelectric body 120A has been described above, the joining between the lifter 110A and the sliding piezoelectric body 120B and the joining between the slider 110B and the sliding piezoelectric body 120B are similarly performed by SAB. .

As described above, this embodiment has the following effects.
(1) Conventionally, in the surface accuracy of the bonding surface, the surface accuracy required at room temperature vacuum bonding is several tens of nm, and if it is more than that (when the surface accuracy is poor), bonding becomes difficult. According to this embodiment, although the PV value of the first bonding surface 12 is about several μm, the metal adheres by vacuum bonding, and good adhesion can be obtained.

(2) According to the second embodiment, an adhesive that inhibits transmission of vibration is used for joining the lifter 110A and the slider 110B, which are the first members, and the lift piezoelectric body 120A and the slide piezoelectric body 120B, which are the second members. Not in. Therefore, the vibration actuator 100 of the second embodiment has good vibration generation efficiency with respect to the drive voltage.

(3) Further, by using such a drive mechanism (joined body) 101 for the vibration actuator 100, drive efficiency is improved, and such a vibration actuator 100 can quickly start and stop. Therefore, when used in the lens barrel 300 or the like, the responsiveness of the operability is good.

(4) In the manufacturing process of the joined bodies 1 and 101, there is no need for manufacturing processes such as application of an adhesive, holding an adhesive state with a fixing jig, heat curing for solidifying the adhesive, and removal of the fixing jig. Thus, productivity can be increased. In addition, management of the application amount (application thickness) of the adhesive, the temperature of the adhesive, the curing temperature, the curing time, and the like becomes unnecessary, and manufacturing management becomes easy.

(5) Since the joined bodies 1 and 101 are joined at room temperature, the first member 10, 110A, 110B and the second member 20, 120A, 120B are not thermally deformed. For this reason, joining is not impaired.

  1: joined body, 10: first member, 11: plating, 12: first joining surface, 20: second member, 22: second joining surface, 100: vibration actuator, 101: drive mechanism (joined body), 110A : Lifter (first member), 110B: Slider (first member), 120A: Lift piezoelectric body (second member), 120B: Slide piezoelectric body (second member), 200: Camera, 300: Lens barrel

Claims (8)

A step of metal plating the surface of the first member;
A step of joining the first member and the second member plated with metal by metal bonding,
The bonding method, wherein the flatness of the bonding surface of the second member is equal to or less than the PV value of the bonding surface of the metal-plated first member. The joining method according to claim 1,
The bonding by the metal bond is a bonding by a surface activation method,
The joining method characterized by this. The joining method according to claim 1 or 2,
The bonding by the metal bond is a vacuum bonding,
The joining method characterized by this. The joining method according to any one of claims 1 to 3,
The joining by the metal bond is a room temperature joining,
The joining method characterized by this. The joining method according to any one of claims 1 to 4,
The PV value of the joint surface of the first member is the particle size of the largest particles present on the joint surface;
The joining method characterized by this. A joining method according to any one of claims 1 to 5,
The metal plating is copper plating;
The joining method characterized by this. A first member having a metal-plated surface;
The flatness of the joint surface with respect to the surface of the first member includes a second member that is equal to or less than the PV value of the joint surface of the first member,
A joined body in which the first member and the second member are metal-bonded. A driving body manufactured by metal-bonding an electromechanical conversion element to the first member whose surface is metal-plated;
A vibration wave motor comprising a relative movement member that is in pressure contact with the drive body and moves relative to the drive body by vibration of the electromechanical transducer,
A vibration actuator in which the flatness of the joint surface of the electromechanical transducer is not more than the PV value of the joint surface of the electromechanical transducer.