JP2017006940A - Ultrasonic bonding device and ultrasonic bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic bonding device and an ultrasonic bonding method which can bond evenly regardless of a position of a chip end face.SOLUTION: A chip 12 is vibrated by a driving source. An anvil 13 faces the chip 12. A conductor 2a of an FFC 2 and a terminal metal fitting 3 are bonded by vibrating the chip 12 while sandwiching the FFC 2 and the terminal metal fitting 3 between the chip 12 and the anvil 13. A plurality of knurl projection parts 12c are provided on an end face of the chips 12 facing the anvil 13. The plurality of knurl projection parts 12c are formed so that the densities are reduced from a center in a direction Y3 orthogonal to a vibration direction Y1 of the chip 12 toward both ends.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an ultrasonic bonding apparatus and an ultrasonic bonding method, and more particularly to an ultrasonic bonding apparatus and an ultrasonic bonding method for bonding an electric wire and a bonding object such as a terminal fitting.

  As the above-described ultrasonic bonding apparatus, for example, it is proposed that the conductor of the electric wire is bonded (metal bonded) by sandwiching the electric wire and another electric wire between the tip and the anvil and vibrating the tip. (Patent Documents 1 and 2).

  However, it is difficult to make the vibration efficiency on the chip end face uniform. For this reason, there existed a problem that the joining state varied according to the position on the chip end face.

  In particular, when a plurality of conductors of the electric wires are arranged in the orthogonal direction and are collectively sandwiched between the chip and the anvil, an electric wire that can be joined and an electric wire that cannot be joined are generated.

JP 2009-43538 A JP 2006-116559 A

  Therefore, an object of the present invention is to provide an ultrasonic bonding apparatus and an ultrasonic bonding method capable of bonding uniformly regardless of the position of the chip end surface.

  The invention according to claim 1, which has been made to solve the above-described problem, includes a chip vibrated by a driving source, an anvil facing the chip, an electric wire and an object to be joined between the chip and the anvil. In an ultrasonic bonding apparatus that bonds the conductor of the wire and the object to be bonded by vibrating the chip by the driving source, relative to the end face of the chip or the chip of the anvil. The ultrasonic bonding apparatus is characterized in that a plurality of protrusions are provided on the end surface, and the plurality of protrusions are formed to have different densities in a direction orthogonal to the vibration direction of the chip. .

  The invention according to claim 2 is characterized in that the plurality of protrusions are formed such that the density decreases from the center in the direction orthogonal to the vibration direction of the chip toward both ends. It exists in the described ultrasonic bonding apparatus.

  According to a third aspect of the present invention, one of the tip and the anvil is provided with a plurality of wall portions extending in parallel and spaced apart from each other, and the protruding portion protrudes from the wall portion. The ultrasonic bonding apparatus according to claim 1, wherein the ultrasonic bonding apparatus is provided.

  Invention of Claim 4 is an ultrasonic joining method using the ultrasonic joining apparatus of Claim 3, Comprising: A plurality of said conductors are arranged in the said orthogonal direction, and each said conductor is one said wall part And the chip or the other of the anvils.

  As described above, according to the first aspect of the present invention, the plurality of protrusions are formed to have different densities in the direction orthogonal to the vibration direction of the chip. As a result, in the part where the vibration efficiency of the chip end face is high in the orthogonal direction, the density of the plurality of protrusions is increased, that is, the number of protrusions per unit area is increased to reduce the pressure and make it difficult to transmit the vibration. In the portion of the chip end face where the vibration efficiency is low, the density of the protrusions is lowered, that is, the number of protrusions per unit area is reduced to increase the pressure to facilitate transmission of vibration. Thereby, it can join uniformly irrespective of the position of a chip | tip end surface.

  According to the second aspect of the present invention, the plurality of protrusions are formed such that the density decreases from the center in the direction orthogonal to the vibration direction of the chip toward both ends. As a result, in the central portion where the vibration efficiency of the chip end face is high, the density of the protrusions is increased, that is, the number of protrusions per unit area is increased to reduce the pressure and make it difficult to transmit the vibration. At the lower ends, the density of the protrusions is lowered, that is, the number of protrusions per unit area is reduced to increase the pressure to facilitate transmission of vibration. Thereby, it can join uniformly irrespective of the position of a chip | tip end surface.

  According to the third aspect of the present invention, one of the chip and the anvil is provided with a plurality of wall portions that extend in parallel and spaced apart from each other. As a result, a plurality of conductors can be sandwiched and uniformly bonded between the plurality of wall portions and the other of the chip or the anvil.

  According to the fourth aspect of the invention, a plurality of conductors can be joined together uniformly.

It is a perspective view showing one embodiment of the ultrasonic joining device of the present invention. It is a perspective view of the chip | tip which comprises the ultrasonic bonding apparatus shown in FIG. It is the elements on larger scale of the chip | tip shown in FIG. (A) And (b) is the front view and bottom view of a chip | tip shown in FIG. (A) And (b) is the elements on larger scale of FIG.4 (b). (A) And (b) is a bottom view of the chip in other embodiments.

  Hereinafter, an ultrasonic bonding apparatus 1 showing an embodiment of the present invention will be described with reference to FIGS. An ultrasonic bonding apparatus 1 shown in FIG. 1 and the like electrically connects a conductor 2a described later of a flexible flat cable (Flexible Flat Cable: hereinafter referred to as FFC) 2 as an electric wire and a terminal fitting 3 as a bonding object. Used for mechanical connection.

  As shown in FIG. 1, the FFC 2 includes a plurality of conductors 2a and a covering portion 2b that covers (ie covers) the plurality of conductors 2a. Each of the plurality of conductors 2a is formed in a strip shape extending linearly, and has a rectangular cross-sectional shape. The plurality of conductors 2a are arranged in parallel (that is, in parallel) with a space therebetween. Of course, each of the conductors 2a has conductivity. In the illustrated example, four conductors 2a are provided.

  As shown in FIG. 1, the covering portion 2 b includes a pair of insulating sheets 2 b 1 and 2 b 2. The insulating sheets 2b1 and 2b2 are made of an insulating synthetic resin and are formed in a strip shape. For this reason, the coating | coated part 2b has insulation of course. The insulating sheets 2b1 and 2b2 cover the conductor 2a with a plurality of conductors 2a interposed therebetween. The conductor 2a and the covering portion 2b have flexibility.

  The terminal fitting 3 is formed by pressing a metal plate such as copper or copper alloy. The terminal fitting 3 has an electrical contact portion 3a connected to a mating terminal (not shown) and a wire connection portion 3b to which the conductor 2a of the FFC 2 is connected.

  In the illustrated example, the electrical contact portion 3a is female and is formed in a cylindrical shape, but may be formed in a male tab shape. The electric wire connecting portion 3b is formed in a strip shape extending linearly, and the electric contact portion 3a is connected to one end in the longitudinal direction.

  The ultrasonic bonding apparatus 1 shown in FIG. 1 superimposes the FFC 2 and the wire connection portion 3b of the terminal fitting 3 and pressurizes them in a direction in which they are brought close to each other, thereby applying ultrasonic vibration energy to the FFC 2 and the terminal fitting 3. By doing so, the coating | coated part 2b is melted and the conductor 2a and the terminal metal fitting 3 are joined.

  The ultrasonic bonding apparatus 1 includes a horn 11 to which a piezoelectric vibrator (not shown) as a drive source is attached, a chip 12 attached to the horn 11, and an anvil 13 facing the chip 12. The piezoelectric vibrator vibrates ultrasonically when AC power is supplied. A tip 12 is attached to the tip of the horn 11 to which the piezoelectric vibrator is attached. For this reason, the piezoelectric vibrator vibrates the chip 12 via the horn 11 or the like. At this time, the vibration direction Y1 of the chip 12 is orthogonal to the contact / separation direction Y2 in which the chip 12 and the anvil 13 contact (separate) each other.

  The ultrasonic bonding apparatus 1 sandwiches the FFC 2 and the terminal fitting 3 that are bonded to each other between the chip 12 and the anvil 13 and pressurizes the chip 12 and the anvil 13 in a direction in which the chip 12 and the anvil 13 approach each other. Is transmitted to the chip 12 via the horn 11. As a result, ultrasonic vibration energy is applied to the FFC 2 and the terminal fitting 3 sandwiched between the chip 12 and the anvil 13 to join each other.

  The chip 12 described above includes an attachment portion 12a, a plurality of wall portions 12b protruding from the attachment portion 12a, and a plurality of knurled protrusion portions 12c (projection portions) respectively protruding from the plurality of wall portions 12b. .

  The attachment portion 12a is provided in a cylindrical shape, and an insertion hole 12d into which the tip end portion of the horn 11 is inserted is provided in the center along the vibration direction Y1 of the horn 11. The tip of the horn 11 is inserted into the insertion hole 12 d and the tip 12 is attached to the horn 11.

  The plurality of wall portions 12b are provided so as to protrude along the contact / separation direction Y2 from the outer surface of the attachment portion 12a. The plurality of wall portions 12b are provided to extend linearly along the vibration direction Y1. The plurality of wall portions 12b are arranged at intervals from each other along an orthogonal direction Y3 (a direction orthogonal to the vibration direction) orthogonal to both the vibration direction Y1 and the contact / separation direction Y2.

  Moreover, as shown to Fig.4 (a), the some wall part 12b is provided so that two height of the both ends side may become high compared with two in the orthogonal direction Y3 center. Thereby, the end surface opposite to the anvil 13 of the plurality of wall portions 12b is provided on the same plane.

  Further, the same number of wall portions 12b as the conductors 2a of the FFC 2 described above are provided, and four wall portions 12b are provided in the illustrated example. The width W1 of the wall portion 12b is provided narrower than the width W2 (see FIG. 1) of the conductor 2a constituting the FFC2. Further, the interval L1 between the wall portion 12b and the wall portion 12b is provided substantially the same as the interval L2 (see FIG. 1) between the conductor 2a and the conductor 2a constituting the FFC2. Thus, when the FFC 2 and the terminal fitting 3 are sandwiched and joined between the chip 12 and the anvil 13, each conductor 2 a is sandwiched between the one wall portion 12 b and the anvil 13.

  The plurality of knurled protrusions 12c are provided so as to protrude in the contact / separation direction Y2 from the end face of the wall 12b facing the anvil 13. The knurl protrusion 12c is provided in a truncated quadrangular pyramid shape. The plurality of knurl protrusions 12c are all provided in the same size and shape.

  As shown in FIGS. 4B and 5, the knurl protrusions 12c are arranged side by side on the two wall portions 12b on the center side in the orthogonal direction Y3 with no gap between the vibration direction Y1 and the orthogonal direction Y3. In the illustrated example, two 2 × 7 = 14 knurl protrusions 12c are provided in the orthogonal direction Y3 and seven in the vibration direction Y1.

  Further, the knurled protrusions 12c are arranged side by side with no gap in the orthogonal direction Y3 on the two wall parts 12b on both ends of the orthogonal direction Y3, but are arranged side by side in the vibration direction Y1. ing. In the illustrated example, two 2 × 3 = 6 knurl protrusions 12c are provided in the orthogonal direction Y3 and three in the vibration direction Y1. As is clear from the above, the plurality of knurled protrusions 12c are formed so that the density decreases from the center of the chip 12 in the orthogonal direction Y3 toward both ends.

  Next, an ultrasonic bonding method using the ultrasonic bonding apparatus having the above-described configuration will be described. First, the wire connection portions 3 b of the plurality of terminal fittings 3 are arranged on the anvil 13. At this time, it arranges along the orthogonal direction Y3 so that the longitudinal direction of the electric wire connection part 3b may follow the vibration direction Y1. The FFC 2 is overlapped on the electric wire connection portion 3b, and the FFC 2 and the terminal fitting 3 are positioned between the chip 12 and the anvil 13. At this time, the plurality of conductors 2a constituting the FFC 2 are arranged side by side along the orthogonal direction Y3 so that the longitudinal direction of the conductor 2a is along the vibration direction Y1.

  Thereby, the some conductor 2a and the electric wire connection part 3b of the some terminal metal fitting 3 oppose on one to one. For this reason, the FFC 2 and the terminal fitting 3 arranged in the center of the orthogonal direction Y3 are sandwiched between the wall portion 12b having many knurl protrusions 12c and the anvil 13, and the FFC 2 and the terminal fitting 3 arranged at both ends are It is sandwiched between the wall portion 12b with few protrusions 12c and the anvil 13.

  Thereafter, the chip 12 and the anvil 13 are brought close to each other, and the FFC 2 and the terminal fitting 3 are pressurized. In this state, the piezoelectric vibrator is vibrated. This vibration is transmitted to the chip 12 via the horn 11. When the chip 12 vibrates, the vibration is transmitted to the FFC 2 and the covering portion 2b of the FFC 2 is melted.

  Since the tip 12 and the anvil 13 are pressurized in a direction approaching each other, the melted covering portion 2b of the FFC 2 is removed from between the conductor 2a and the terminal fitting 3 sandwiched between the tip 12 and the anvil 13. Further, the removed covering portion 2b enters (accommodates) a groove between the wall portion 12b and the wall portion 12b.

  The conductor 2a and the terminal fitting 3 are brought into contact with each other. When vibration is applied in a state where the conductor 2a and the terminal fitting 3 are in contact with each other, the conductor 2a and the terminal fitting 3 are joined.

  According to the above-described embodiment, the plurality of knurl protrusions 12c are formed so that the density decreases from the center of the chip 12 in the orthogonal direction Y3 toward both ends. As a result, in the central portion where the vibration efficiency of the end face of the chip 12 is high, the density of the knurl projections 12c is increased, that is, the number of knurl projections 12c per unit area is increased to reduce the pressure and make it difficult to transmit vibration. At both ends of the 12 end faces where the vibration efficiency is low, the density of the knurl projections 12c is lowered, that is, the number of knurl projections 12c per unit area is reduced to increase the pressure to facilitate transmission of vibration. Thereby, it can join uniformly irrespective of the position of the chip | tip 12 end surface. That is, in this embodiment, the conductor 2a arranged at the center of the orthogonal direction Y2 and the conductor 2a arranged at both ends can be joined uniformly.

  Further, according to the above-described embodiment, the plurality of wall portions 12b extending in parallel straight lines at intervals are provided on the end surface of the chip 12. As a result, the plurality of conductors 2a can be sandwiched between the plurality of wall portions 12b and the anvil so as to be uniformly joined together.

  Further, according to the above-described embodiment, when the conductors 2a of the plurality of FFCs 2 are arranged in the orthogonal direction Y3 and sandwiched and joined between the chip 12 and the anvil 13, one conductor 2a becomes one wall portion 12b and the anvil. 13 between them. Thereby, the several conductor 2a can be put together and joined to the terminal metal fitting 3 at once.

  According to the above-described embodiment, the vibration efficiency at the center portion in the orthogonal direction Y3 of the end face of the chip 12 is high and the vibration efficiency at both sides thereof is low. Although it was formed so that a density became low as it went to both ends from the center, it is not restricted to this.

  For example, depending on the shape of the electric wire (FFC2 in the present embodiment), the shape of the object to be bonded (terminal fitting 3 in the present embodiment), and the characteristics of the piezoelectric vibrator, the vibration efficiency at the center of the end surface of the chip 12 is high. The vibration efficiency on both sides of the orthogonal direction Y3 is not necessarily lowered. In some cases, locations where the vibration efficiency is high and locations where the vibration efficiency is low appear alternately along the orthogonal direction Y3, or conversely, the vibration efficiency at the ends of the orthogonal direction Y3 is high because the vibration efficiency at the center is low. Sometimes. In such a case, the plurality of knurled protrusions 12c may be formed so that the density is high at a location where the vibration efficiency is high and the density is low at a location where the vibration efficiency is low.

  Specifically, when the location where the vibration efficiency is high and the location where the vibration efficiency is low appear alternately along the orthogonal direction Y3, the density of the knurl protrusions 12c is high as shown in FIG. What is necessary is just to form so that the wall part 12b and the wall part 12b with a low density may be arranged by turns. If the vibration efficiency at the center is low and the vibration efficiency at both ends of the orthogonal direction Y3 is high, as shown in FIG. 6B, the density of the knurl projections 12c provided on the two wall portions 12b is lowered, What is necessary is just to form the density of the knurl protrusion 12c provided in the wall part 12b of the orthogonal | vertical direction Y3 both sides high.

  Further, according to the above-described embodiment, the tip 12 is one of the tip 12 and the anvil 13, the anvil 13 is the other of the tip 12 and the anvil 13, and the wall 12 b and the knurled protrusion 12 c are provided on the tip 12. However, it is not limited to this. The anvil 13 may be provided with a wall 12b and a knurl projection 12c.

  Moreover, according to embodiment mentioned above, although the terminal metal fitting 3 was mentioned as an example as a joining target object, it is not restricted to this. The joining object may be a conductor of another electric wire, a metal plate, or a conductive sheet.

  Further, according to the embodiment described above, the truncated quadrangular pyramid-shaped knurled protrusion 12c is taken as an example of the protruding portion, but the shape of the protruding portion is not limited to this, and a truncated cone is used. The shape may be sufficient, and the shape extended linearly in the orthogonal direction Y3 may be sufficient.

  Further, according to the above-described embodiment, the knurled protrusion 12c is provided on the wall 12b. However, the present invention is not limited to this. The wall 12b is not essential.

  Moreover, in embodiment mentioned above, although FFC2 was used as an electric wire, it is not restricted to this. An electric wire having a round cross section may be used as the electric wire.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

1 Ultrasonic bonding device 2 FFC (electric wire)
2a Conductor 3 Terminal fitting (object to be joined)
12 chip 12b wall 12c nar protrusion (protrusion)
13 Anvil Y1 Vibration direction Y3 Orthogonal direction (direction orthogonal to vibration direction)

Claims (4)

A chip vibrated by a driving source, an anvil facing the chip, an electric wire and an object to be joined are sandwiched between the chip and the anvil, and the chip is vibrated by the driving source to conduct the conductor of the electric wire And an ultrasonic bonding apparatus for bonding the object to be bonded,
A plurality of protrusions are provided on an end surface of the tip that faces the anvil or an end surface of the anvil that faces the tip,
The plurality of protrusions are formed to have different densities in a direction orthogonal to the vibration direction of the chip. 2. The ultrasonic bonding apparatus according to claim 1, wherein the plurality of protrusions are formed so as to decrease in density from a center in a direction orthogonal to a vibration direction of the chip toward both ends. One of the tip or the anvil is provided with a plurality of walls extending in parallel and spaced apart from each other,
The ultrasonic bonding apparatus according to claim 1, wherein the protruding portion is provided so as to protrude from the wall portion. An ultrasonic bonding method using the ultrasonic bonding apparatus according to claim 3,
A plurality of the conductors are arranged in the orthogonal direction, and each conductor is sandwiched and joined between one wall portion and the other of the tip or the anvil.

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