Ultrasonic bonding horn and ultrasonic bonding method

Abstract

To provide an ultrasonic joining horn which can accurately join a joined material arranged so as to close a hole part onto a substrate.SOLUTION: An ultrasonic joining horn 1 is used in ultrasonic joining treatment of applying ultrasonic vibration to a joined material arranged on a surface of a substrate, and joining the joined material onto the surface of the substrate. In the ultrasonic joining horn 1, a joining block 12 is connected to a surface of a base 11, and a tip projection 10 is provided on a tip of the joining block 12. The tip projection 10 is provided into such a cylindrical shape as to have an internal space SP1. A projection height h10 of the tip projection 10 is set at 0.1 mm or more and 0.2 mm or less, and a projection thickness t10 of the tip projection 10 is set at 0.15 mm or more and 0.25 mm or less.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an ultrasonic bonding horn used for ultrasonic bonding treatment for bonding a material to be bonded to the surface of a substrate.

Background Art

[0002] A glass plate serving as a cover glass for an organic device is provided to protect a photoelectric conversion unit (power generation layer). The glass plate is provided as a cover on the upper part of the photoelectric conversion unit. However, in order to secure a conduction path from the photoelectric conversion unit, a hole is made in the glass plate, and a metal foil, which is a current collecting electrode, is placed to close the hole, and an ultrasonic bonding treatment is performed to bond the metal foil onto the glass plate. After the metal foil is bonded to the glass plate, the electrical connection between the metal foil and the photoelectric conversion unit is performed using existing techniques. In the above-described ultrasonic bonding treatment, the glass plate functions as a substrate, and the metal foil functions as a material to be bonded that closes the hole.

[0003] An ultrasonic bonding horn used for ultrasonic bonding treatment has a tip protrusion that contacts the material to be bonded when performing the ultrasonic bonding treatment. As a conventional ultrasonic bonding horn having a tip protrusion, for example, there are a rule for ultrasonic bonding disclosed in Patent Document 1 and an ultrasonic bonding horn disclosed in Patent Document 2.

[0004] FIG. 11 is an explanatory view schematically showing a side structure of a conventional ultrasonic bonding horn 50. FIG. 12 is a plan view schematically showing a planar structure of a tip protrusion 60 of the ultrasonic bonding horn shown in FIG. 11. An XYZ orthogonal coordinate system is shown in each of FIGS. 11 and 12.

[0005] As shown in these figures, the conventional ultrasonic bonding horn 50 includes a base 61, a bonding block 62, and a tip protrusion 60 as main components.

[0006] The bonding block 62 is connected to the surface on the -Z direction side of the base 61, and the tip protrusion 60 is provided at the tip on the -Z direction side of the bonding block 62. The tip protrusion 60 becomes a part that contacts the material to be bonded when performing the ultrasonic bonding treatment.

[0007] As shown in FIG. 11, the tip projection 60 has a valley shape in which convex portions and concave portions appear alternately. The valley shape is a shape in which a plurality of triangles are connected in the YZ cross section. Instead of this valley shape, it may be a dot shape having a plurality of concave portions on a flat surface.

[0008] As shown in FIG. 12, the tip projection 60 has a rectangular surface that is rectangular in plan view, and a valley shape is provided over the entire rectangular surface.

[0009] The tip projection 60 in the conventional ultrasonic bonding horn 50 shown in FIGS. 11 and 12 has a valley shape provided over the entire rectangular surface. By performing an ultrasonic bonding process in a state where the tip projection 60 is brought into contact with a material to be bonded provided on a substrate using such an ultrasonic bonding horn 50, the material to be bonded is bonded onto the surface of the substrate.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0011] Consider a hypothetical bonding situation in which an ultrasonic bonding process is performed on a material to be bonded that is disposed to close a hole provided in a substrate using the above-described conventional ultrasonic bonding horn 50. In the hypothetical bonding situation, a glass substrate is assumed as the substrate, a glass through-hole that penetrates the glass substrate is assumed as the hole, and a metal foil such as aluminum foil is assumed as the material to be bonded.

[0012] In the case of the above-described assumed bonding situation, with the tip protrusion 60 in contact with the metal foil, ultrasonic vibration is applied to the ultrasonic bonding horn 50 from above the base 61 side, and an ultrasonic bonding process for bonding the metal foil onto the surface of the glass substrate is executed.

[0013] In the above-described assumed bonding situation, in the area above the through-hole above the glass through-hole, the valley shape of the tip protrusion 60 and the metal foil are in contact. That is, when the ultrasonic bonding process is executed, the tip protrusion 60 of the ultrasonic bonding horn 50 and the glass through-hole interfere with each other, and the area below the area of the metal foil above the through-hole becomes a space area (glass through-hole).

[0014] For this reason, in the above-described assumed bonding situation, when the ultrasonic bonding process is executed, a force is exerted by the ultrasonic bonding horn 50 to push down the metal foil toward the space area of the glass through-hole, so there is a first problem that the metal foil breaks.

[0015] In addition, in the above-described assumed bonding situation, when the ultrasonic bonding process is executed, a force is exerted by the ultrasonic bonding horn 50 to push down the inner peripheral surface of the glass through-hole via the metal foil, so there is a second problem that the glass through-hole cracks.

[0016] As described above, when the ultrasonic bonding process is executed using the conventional ultrasonic bonding horn 50 having a valley shape or a dot shape as the tip protrusion 60, the above-described first and second problems occur, so there is a problem that the metal foil closing the glass through-hole cannot be accurately bonded onto the glass substrate.

[0017] The present disclosure has been made to solve the above problems, and an object thereof is to obtain an ultrasonic bonding horn capable of accurately bonding a bonded material disposed by closing a hole portion onto a substrate.

Means for Solving the Problems

[0018] The ultrasonic bonding horn according to the present disclosure is an ultrasonic bonding horn used for an ultrasonic bonding process of applying ultrasonic vibration to a material to be bonded disposed on the surface of a substrate and bonding the material to be bonded on the surface of the substrate, and includes a bonding block and a tip protrusion provided at the tip of the bonding block and contacting the material to be bonded during execution of the ultrasonic bonding process. The tip protrusion is provided in a cylindrical shape having an internal space.

Advantages of the Invention

[0019] Since the tip protrusion in the ultrasonic bonding horn of the present disclosure is provided in a cylindrical shape having an internal space, ultrasonic vibration is not applied to the internal space of the tip protrusion during execution of the ultrasonic bonding process.

[0020] Therefore, when the substrate has a hole portion and the material to be bonded is provided so as to block the hole portion, and the planar shape of the internal space of the tip protrusion is set wider than that of the hole portion, the ultrasonic bonding process using the ultrasonic bonding horn of the present disclosure can be executed in a protrusion contact state where the material to be bonded and the tip protrusion are brought into contact with each other on the peripheral region of the hole portion.

[0021] As a result, by executing the ultrasonic bonding process using the ultrasonic bonding horn of the present disclosure, the material to be bonded can be accurately bonded onto the substrate without interfering with the hole portion.

Brief Description of the Drawings

[0022]

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Mode for Carrying Out the Invention

[0023] <Embodiment> (Structure of Ultrasonic Bonding Horn) FIG. 1 is an explanatory diagram schematically showing the side structure of an ultrasonic bonding horn 1 which is an embodiment of the present disclosure. FIG. 2 is an explanatory diagram showing an enlarged side structure of the focused area R1 of the ultrasonic bonding horn 1 shown in FIG. 1. FIG. 3 is an explanatory diagram schematically showing the planar structure of the ultrasonic bonding horn 1 shown in FIG. 1 viewed from below. FIG. 4 is an explanatory diagram showing an enlarged planar structure of the focused area R2 of the ultrasonic bonding horn 1 shown in FIG. 3. An XYZ orthogonal coordinate system is marked in each of FIGS. 1 to 4.

[0024] As shown in these figures, the ultrasonic bonding horn 1 of the present embodiment includes a base 11, a bonding block 12, and a tip projection 10 as main components.

[0025] The ultrasonic bonding horn 1 is used for an ultrasonic bonding process in which an ultrasonic vibration is applied to a material to be bonded on the surface of a substrate by closing a hole provided in the substrate and arranging the material to be bonded on the surface of the substrate, thereby bonding the material to be bonded on the surface of the substrate.

[0026] A bonding block 12 is connected to the surface on the -Z direction side of the base 11, and a tip protrusion 10 is provided at the tip on the -Z direction side of the bonding block 12. The tip protrusion 10 becomes a part that contacts the material to be bonded during the ultrasonic bonding process.

[0027] As shown in FIG. 3, the tip protrusion 10 is provided in a cylindrical shape having an internal space SP1. That is, the tip protrusion 10 has an annular shape with a protrusion inner diameter d10 in a plan view. The region within the protrusion inner diameter d10 of the tip protrusion 10 becomes the internal space SP1.

[0028] As shown in FIGS. 1 and 2, the protrusion height h10, which is the formation height of the tip protrusion 10 along the Z direction, is set to be 0.1 mm or more and 0.2 mm or less.

[0029] As shown in FIGS. 3 and 4, the protrusion wall thickness t10, which is the radial thickness of the tip protrusion 10, is set to be 0.15 mm or more and 0.25 mm or less.

[0030] (Ultrasonic Bonding Method) FIG. 5 is a flowchart showing the processing procedure of the ultrasonic bonding method using the ultrasonic bonding horn 1 of the present embodiment. FIGS. 6 to 9 are explanatory diagrams schematically showing the usage status of the ultrasonic bonding horn 1. An XYZ orthogonal coordinate system is shown in each of FIGS. 6 to 9.

[0031] Hereinafter, with reference to FIG. 5 and appropriately citing FIGS. 6 to 9, the processing procedure of the ultrasonic bonding method using the ultrasonic bonding horn 1 will be described.

[0032] As shown in FIG. 6, the glass plate 20, which is a substrate to be ultrasonically bonded, has a glass through-hole 21. In FIG. 6, the formation surface of the glass plate 20 is taken as the XY plane.

[0033] Returning to FIG. 5, in step S1, the diameter (diameter) of the glass through-hole 21 is recognized. For example, the diameter of the glass through-hole 21 can be recognized by performing a manual measurement process using a caliper or a microscope.

[0034] The glass plate 20 is provided on the photoelectric conversion part, for example, as a cover member that protects the photoelectric conversion part (power generation layer) of a solar cell. In order to electrically connect to the photoelectric conversion part with this structure, a glass through hole 21 for reaching the photoelectric conversion part is provided in the glass plate 20. The glass through hole 21 becomes a hole part provided in the substrate.

[0035] After that, in step S2, the ultrasonic bonding horn 1 corresponding to the glass through hole 21 recognized in step S1 is prepared as the hole part ultrasonic bonding horn 1X.

[0036] For example, when the diameter of the glass through hole 21 is diameter d21, the ultrasonic bonding horn 1 having a tip protrusion 10 with a protrusion inner diameter d10 that is longer than the diameter d21 by a length ΔD is used as the hole part ultrasonic bonding horn 1X. Here, the length ΔD is set to 1.0 mm or more.

[0037] Hereinafter, the tip protrusion 10 of the hole part ultrasonic bonding horn 1X prepared in step S2 will be specifically described by referring to it as the "selected tip protrusion 10X".

[0038] Next, in step S3, as shown in FIG. 6, the hole part ultrasonic bonding horn 1X is arranged above the glass through hole 21. Specifically, with the bonding block 12 below the base 11, the hole part ultrasonic bonding horn 1X is arranged so that the tip protrusion 10 (not shown in FIG. 6) faces the glass plate 20. Further, it is arranged so that the center of the glass through hole 21 coincides with the center of the tip protrusion 10 in a plan view.

[0039] Next, in step S4, as shown in FIG. 7, an aluminum foil 25 is arranged on the glass plate 20 to block the glass through hole 21. Specifically, the aluminum foil 25, which is a metal foil, is arranged on the surface of the glass plate 20 so as to cover all of the glass through hole 21. The aluminum foil 25 becomes a material to be bonded provided on the surface of the glass plate 20. In the case of a solar cell structure, the aluminum foil 25 functions as a current collecting electrode.

[0040] Then, in step S5, an ultrasonic bonding process is performed on the aluminum foil 25 disposed on the surface of the glass plate 20 in step S4 using the ultrasonic bonding horn 1X for holes.

[0041] First, as shown in FIG. 7, the ultrasonic bonding horn 1X for holes is lowered while applying a predetermined load along the downward direction D1. The downward direction D1 coincides with the -Z direction.

[0042] Then, as shown in FIG. 8, the ultrasonic bonding process using the ultrasonic bonding horn 1X for holes is executed with the selected tip protrusion 10X (not shown in FIG. 8) provided at the tip of the bonding block 12 being in a protrusion contact state of contacting the aluminum foil 25 while applying a predetermined load, thereby bonding the aluminum foil 25 onto the surface of the glass plate 20.

[0043] At this time, it becomes a position setting state where the glass through-hole 21 is located within the internal space SP1 of the selected tip protrusion 10X in a plan view. That is, in the protrusion contact state, the selected tip protrusion 10X contacts the aluminum foil 25 on the peripheral region of the glass through-hole 21 without interfering with the glass through-hole 21.

[0044] Thus, step S5 is a step of executing an ultrasonic bonding process in a position setting state where the glass through-hole 21 is located within the internal space SP1 of the selected tip protrusion 10X in a plan view, using the ultrasonic bonding horn 1X for holes having the selected tip protrusion 10X.

[0045] This position setting state is achieved because the following dimensional arrangement settings (1) to (3) are made. (1) The selected tip protrusion 10X has a protrusion inner diameter d10 that is longer by a length ΔD than the diameter d21 of the glass through-hole 21. (2) In step S3, the center of the glass through-hole 21 and the center of the tip protrusion 10 are arranged to coincide in a plan view. (3) In step S5, the ultrasonic bonding horn 1X for holes is lowered along the downward direction D1 to bring the tip protrusion 10 into contact with the aluminum foil 25.

[0046] Thereafter, as shown in FIG. 9, the ultrasonic bonding horn 1X for the hole portion is raised along the upward direction D2 to eliminate the protrusion contact state and end the ultrasonic bonding process.

[0047] As a result, as shown in FIG. 9, an annular bonding mark 30 reflecting the planar shape of the selected tip protrusion 10X remains on the aluminum foil 25.

[0048] FIG. 10 is an explanatory diagram schematically showing the planar structure of the aluminum foil 25 after the execution of the ultrasonic bonding process in step S5. An XYZ orthogonal coordinate system is shown in FIG. 10.

[0049] As shown in the figure, a bonding mark 30 with an inner diameter that is longer than the diameter d21 of the glass through-hole 21 by a length ΔD remains on the aluminum foil 25. The thickness in the radial direction of the bonding mark 30 is approximately the same as the protrusion thickness t10. Note that the length ΔD is set to 1.0 mm or more in step S2.

[0050] (Effect) Since the tip protrusion 10 in the ultrasonic bonding horn 1 (1X) of the present embodiment is provided in a cylindrical shape having an internal space SP1, ultrasonic vibration is not applied to the internal space SP1 of the tip protrusion 10 (10X) during the execution of the ultrasonic bonding process.

[0051] As shown in FIGS. 6 to 9, the glass plate 20 has a glass through-hole 21 serving as a hole portion, the aluminum foil 25 serving as the material to be bonded is provided so as to block the glass through-hole 21, and the planar shape of the internal space SP1 of the ultrasonic bonding horn 1 (1X) is set wider than that of the glass through-hole 21. In the case of the configuration shown in FIGS. 6 to 9, an ultrasonic bonding process can be performed by the ultrasonic bonding horn 1 in a protrusion contact state in which the aluminum foil 25 and the tip protrusion 10 are in contact with each other on the peripheral region of the glass through-hole 21.

[0052] As a result, by performing the ultrasonic bonding process using the ultrasonic bonding horn 1 of the present embodiment, the aluminum foil 25 can be accurately bonded onto the surface of the glass plate 20 without interfering with the glass through-hole 21.

[0053] In addition, in this embodiment, the shape of the tip projection 10 is cylindrical, but it may be formed in a square tube shape. That is, the tip projection 10 can exhibit the above-described effects by being formed in a tubular shape (cylindrical or square tube shape) having an internal space.

[0054] However, since the hole portion is generally provided in a cylindrical shape like the glass through-hole 21, it is desirable that the shape of the tip projection 10 also be formed in a cylindrical shape reflecting the shape of the glass through-hole 21. In this case, the ultrasonic bonding horn 1 of Embodiment 1 can be set to the minimum necessary length ΔD during the execution of the ultrasonic bonding process, and interference with the circular glass through-hole 21 in plan view can be appropriately avoided.

[0055] The ultrasonic bonding horn 1 of this embodiment can surely avoid a phenomenon in which a part of the tip region of the bonding block 12 other than the tip projection 10 contacts the aluminum foil 25 during the execution of the ultrasonic bonding process by setting the projection height h10, which is the formation height of the tip projection 10, to 0.1 mm or more, and can bond the aluminum foil 25 onto the surface of the glass plate 20.

[0056] The ultrasonic bonding horn 1 of this embodiment can bond the aluminum foil 25 onto the surface of the glass plate 20 while keeping the ultrasonic vibration content of the tip projection 10 with respect to the aluminum foil 25 constant without changing it during the execution of the ultrasonic bonding process by setting the projection height h10 of the tip projection 10 to 0.2 mm or less.

[0057] The ultrasonic bonding horn 1 of this embodiment can bond the aluminum foil 25 onto the surface of the glass plate 20 by setting the projection thickness t10, which is the thickness of the tip projection 10 in the radial direction, to 0.15 mm or more and 0.25 mm or less, thereby putting the load applied to the tip projection 10 in an appropriate state.

[0058] Hereinafter, this point will be described in detail. If the protrusion thickness t10 is less than 0.15 mm, the load applied to the tip protrusion 10 becomes too large, and there is a risk of cracking the aluminum foil 25. On the other hand, when the protrusion thickness t10 exceeds 0.25 mm, the load applied to the tip protrusion 10 becomes too small compared to the desired value, and there is a possibility that the aluminum foil 25 cannot be properly joined onto the surface of the glass plate 20.

[0059] Therefore, by setting the protrusion thickness t10 of the tip protrusion 10 to be 0.15 mm or more and 0.25 mm or less, the load applied to the selected tip protrusion 10X can be made appropriate.

[0060] The inner diameter d10 of the protrusion of the tip protrusion 10 (10X) of the ultrasonic bonding horn 1 (1X) of the present embodiment is set to be longer by a length ΔD of 1 mm or more compared to the diameter d21 of the glass through-hole 21. For this reason, the total misalignment amount due to the misalignment of the center position and the horizontal vibration distance of the ultrasonic bonding process during the execution of step S3 can be suppressed within the length ΔD.

[0061] Note that the "misalignment of the center position" means the misalignment between the center of the tip protrusion 10 and the center of the glass through-hole 21, and the "horizontal vibration distance" means the vibration distance in the horizontal direction of the tip protrusion 10 during the execution of the ultrasonic bonding process in step S5. The horizontal vibration distance is assumed to be about 20 μm.

[0062] Therefore, even considering the above-described misalignment of the center position and the horizontal vibration distance, the ultrasonic bonding horn 1 of the present embodiment can maintain the position setting state in which the glass through-hole 21 is located within the internal space SP1 of the tip protrusion 10 in a plan view during the execution period of the ultrasonic bonding process.

[0063] As a result, the ultrasonic bonding horn of the present embodiment can surely avoid the phenomenon that the tip protrusion 10 and the glass through-hole 21 provided in the glass plate 20 interfere with each other, and can accurately bond the aluminum foil 25 onto the surface of the glass plate 20.

[0064] In step S2 of the ultrasonic bonding method of the present embodiment shown in FIG. 5, the inner diameter d10 of the protruding tip 10X of the ultrasonic bonding horn 1X for holes is set to be longer by a length ΔD of 1 mm or more compared to the diameter d21 of the glass through-hole 21.

[0065] In step S5 executed after steps S3 and S4 of the ultrasonic bonding method of the present embodiment, the ultrasonic bonding process is executed in a position setting state where the glass through-hole 21 is located inside the internal space SP1 of the protruding inner diameter d10 of the selected tip protrusion 10X in a plan view.

[0066] Therefore, even considering the above-mentioned center position deviation that occurs during the execution of step S3 and the above-mentioned horizontal vibration distance that occurs during the execution of step S5, it is possible to surely avoid the phenomenon that the selected tip protrusion 10X and the glass through-hole 21 provided in the glass plate 20 interfere with each other during the execution period of the ultrasonic bonding process in step S5.

[0067] As a result, the ultrasonic bonding method of the present embodiment can accurately bond the aluminum foil 25 disposed so as to block the glass through-hole 21 to the glass plate 20.

[0068] Note that within the scope of the present disclosure, the embodiments can be appropriately modified and omitted.

Explanation of Reference Numerals

[0069] 1 Ultrasonic bonding horn, 1X Ultrasonic bonding horn for holes, 10 Tip protrusion, 10X Selected tip protrusion, 11 Base, 12 Bonding block, 20 Glass plate, 21 Glass through-hole, 25 Aluminum foil, 30 Bonding mark, d10 Protrusion inner diameter, h10 Protrusion height, t10 Protrusion wall thickness.

Claims

1. An ultrasonic bonding horn used in an ultrasonic bonding process for applying ultrasonic vibration to a material to be bonded disposed on the surface of a substrate and bonding the material to be bonded on the surface of the substrate, comprising: a bonding block; a tip protrusion provided at the tip of the bonding block and contacting the material to be bonded during the execution of the ultrasonic bonding process, wherein the tip protrusion is provided in a cylindrical shape having an internal space, and the formed height of the tip protrusion is constant, wherein the tip protrusion is provided in a cylindrical shape having an internal space, wherein the substrate is a glass plate having a hole, wherein the material to be bonded is a metal foil for closing the hole, wherein the inner diameter of the tip protrusion is set to be 1 mm or more longer than the diameter of the hole, an ultrasonic bonding horn.

2. The ultrasonic bonding horn according to claim 1, wherein the formed height of the tip protrusion is set to be 0.1 mm or more and 0.2 mm or less. an ultrasonic bonding horn.

3. The ultrasonic bonding horn according to claim 1, wherein the radial thickness of the tip protrusion is set to be 0.15 mm or more and 0.25 mm or less. an ultrasonic bonding horn.

4. An ultrasonic bonding method for applying ultrasonic vibration to a material to be bonded disposed on the surface of a substrate and performing an ultrasonic bonding process for bonding the material to be bonded on the surface of the substrate, wherein the substrate has a hole, (a) a step of recognizing the diameter of the hole; (b) a step of preparing an ultrasonic bonding horn corresponding to the hole recognized in the step (a) as an ultrasonic bonding horn for the hole, wherein the ultrasonic bonding horn for the hole comprises: a bonding block; a tip protrusion provided at the tip of the bonding block and contacting the material to be bonded during the execution of the ultrasonic bonding process, wherein the tip protrusion is provided in a cylindrical shape having an internal space, and the formed height of the tip protrusion is constant, wherein the inner diameter of the tip protrusion is set to be 1 mm or more longer than the diameter of the hole, wherein the ultrasonic bonding method further comprises: (c) a step of disposing the material to be bonded on the substrate while closing the hole; (d) a step of performing the ultrasonic bonding process in a position setting state where the hole is located within the internal space of the tip protrusion in a plan view using the ultrasonic bonding horn for the hole. an ultrasonic bonding method.

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