JP5648200B2 - Joining method - Google Patents

Description

  The present invention relates to a technique for joining objects to be joined having metal joints by applying ultrasonic vibration.

  2. Description of the Related Art Conventionally, a technique for joining objects to be joined having metal joints by applying ultrasonic vibration is known. For example, in the joining apparatus described in Patent Document 1, a gold-plated electrode on a flexible substrate that is attracted and held by a horn and a gold-plated electrode on a glass substrate placed on a substrate holder provided on a movable table are aligned and flexible. By applying ultrasonic vibration in a state where the substrate is pressed against the glass substrate by a horn and pressed, the flexible substrate is bonded to a predetermined position of the glass substrate.

JP 2007-317932 A (paragraphs 0023-0027, FIGS. 1-3, etc.)

  In metal bonding using ultrasonic vibration, oxide film, dust, dust, etc. are removed by applying ultrasonic vibration to both objects to be bonded in a state where the metal bonding portions are in contact with each other, thereby removing metal. The new surfaces generated at the joint interface of the joint are joined together. Therefore, in order to improve the bonding strength between the metal joints of both objects to be bonded and to achieve good bonding, the area of the new surface generated at the bonding interface of the metal joints is rubbed by ultrasonic vibration. It is important to apply ultrasonic vibrations in a state where the metal joints of both objects to be joined are in reliable contact with each other.

  However, when at least one of the objects to be joined is made of a resin material that is softer than the metal that forms the metal joint, such as a glass epoxy substrate or a flexible substrate, the metal joints are in contact with each other When both of the objects to be bonded are pressurized, the object to be bonded formed of a soft material may be deformed, and a gap may be generated at the bonding interface where the metal bonding parts of both objects to be bonded contact. In this case, ultrasonic vibration is not sufficiently applied to the bonding interface of the metal bonding portion, which causes a bonding failure, which is a problem.

  In addition, if at least one of the objects to be bonded is formed of a soft material such as a resin, the applied ultrasonic vibration is transmitted to and absorbed by the object to be bonded formed of a soft material. When the ultrasonic vibration applied to the joint interface where the metal joints of the two parts are in contact is reduced and the metal joints of both objects are formed of a hard material such as Cu, a new surface is sufficiently formed in the metal joints. Since it is not generated and causes poor bonding, improvement in technology is required.

  In addition, when the metal joint portion of one of the objects to be joined is formed in a thin film shape and the other object to be joined is a core wire or a lead frame, the core wire or the lead frame is made of a thin film shape of one of the objects to be joined. Even if it is intended to join directly to the metal joint by ultrasonic vibration, the thin-film metal joint may not be joined due to peeling or the like.

  The present invention has been made in view of the above-described problems, and a foil-like conductive material is interposed between both metal joints when joining objects to be joined that are difficult to join by simply applying ultrasonic vibration. It is an object of the present invention to provide a technique capable of satisfactorily joining objects to be joined by applying ultrasonic vibration in a state of being made.

In order to achieve the above-described object, the joining method according to the present invention is a joining method in which ultrasonic vibration is applied to join objects to be joined having metal joints. A step of temporarily joining a metal foil-like conductive material by applying ultrasonic vibration to an electrode pattern for electrical connection provided as a metal joint on an organic substrate having flexibility; and the foil-like shape of the organic substrate The metal bonding part of the other object to be bonded is connected to the electrode pattern to which a conductive material is temporarily bonded, and the foil is interposed between the electrode pattern of the organic substrate and the metal bonding part of the other object to be bonded. A step of applying ultrasonic vibration in a state of interposing a conductive material, and preparing a tape material provided with the foil-shaped conductive material in the temporary bonding step, and performing the bonding once As many as required in the process Temporarily bonding the flaky material by transferring from said tape material to said electrode pattern of the organic substrate, the thickness of the foil-shaped material is, it is characterized in that greater than a thickness of the electrode pattern of the organic substrate ( Claim 1).

Further, in the temporary bonding step, the foil-like conductive material is transferred from the tape material to the electrode pattern of the one organic substrate and temporarily bonded. A new foil-like conductive material is transferred from the tape material to the electrode pattern of the organic substrate and temporarily joined (claim 2).

  The foil-like conductive material may be made of any one of Al, Ag, Au, Cu, Ni, Pt, Cr, Pd, In, and solder.

  Moreover, it is good in the film thickness of the said foil-like electrically conductive material being 5-1000 micrometers (Claim 4).

Further, the other object to be joined is a lead frame (claim 5 ).

Further, the other object to be joined is a core wire (claim 6 ).

  According to the first aspect of the present invention, when joining objects to be joined that are difficult to be joined only by applying ultrasonic vibrations, a metal foil-like conductive material is provided between the metal joints of both objects to be joined. By applying ultrasonic vibration in the state where the joint is interposed, there is no possibility that a gap or the like is generated at the joint interface due to the foil-like conductive material interposed between the metal joints even if the workpiece is deformed. Since the foil-like conductive material prevents the parts from coming into direct contact with each other, ultrasonic vibration is reliably applied to the joint interface formed by contacting both metal joints on both sides of the foil-like conductive material. And since both metal joining parts are reliably joined via foil-like electrically-conductive material, the to-be-joined objects which have a metal joining part can be joined favorably.

In addition, the foil-like conductive material is temporarily joined to the metal joint by ultrasonic vibration, and the other joint is joined by ultrasonic vibration to the one to-be-joined object. Ultrasonic vibration can be applied with the conductive material reliably interposed. In addition, it is difficult to bond by simply applying ultrasonic vibration, and it can be electrically connected to a rigid organic substrate such as a glass epoxy substrate or a flexible organic substrate formed of polyimide or the like as a metal bonding portion. An object to be joined provided with the electrode pattern for connection can be reliably joined. Moreover, a foil-like conductive material can be temporarily joined to each electrode pattern continuously, or a plurality of foil-like conductive materials can be temporarily joined to each electrode pattern simultaneously.
And joining strength can be improved reliably.
According to the invention described in claim 2, as in the invention described in claim 1, the foil-like conductive material can be efficiently temporarily joined to the electrode pattern.

  According to the invention described in claim 3, the foil-like conductive material can be easily formed from any one of Al, Ag, Au, Cu, Ni, Pt, Cr, Pd, In, and solder.

  According to invention of Claim 4, since the film thickness of foil-shaped electrically-conductive material is 5-1000 micrometers, it is practical.

According to the inventions described in claims 5 and 6 , it is difficult to join only by applying ultrasonic vibration, and it is possible to reliably join objects to be joined made of a lead frame or a core wire.

It is a figure which shows one Embodiment of the joining apparatus with which the joining method of this invention is performed. It is a figure which shows an example of a to-be-joined object, Comprising: (a) is a perspective view, (b) is a principal part enlarged view. It is a flowchart which shows an example of a joining process. It is a figure which shows an example of joining strength. It is a figure which shows an example of a to-be-joined object. It is a figure which shows an example of joining strength. It is a figure which shows an example of a to-be-joined object, Comprising: (a) is a perspective view, (b) is a principal part enlarged view. It is a figure which shows an example of joining strength. It is a principal part enlarged view which shows an example of a to-be-joined object, Comprising: (a) is a figure which shows the state before joining, (b) is a figure which shows the state after joining. It is a figure which shows an example of a foil-like electrically conductive material. It is a figure which shows an example of a foil-like electrically conductive material.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a view showing an embodiment of a joining apparatus in which the joining method of the present invention is executed. 2A and 2B are views showing an example of an object to be joined, where FIG. 2A is a perspective view and FIG. 2B is an enlarged view of a main part. FIG. 3 is a flowchart showing an example of the joining process. FIG. 4 is a diagram illustrating an example of bonding strength.

(Joining equipment)
A joining apparatus 100 shown in FIG. 1 is an apparatus that joins objects to be joined having metal joints by applying ultrasonic vibrations, and includes lead frames, flexible substrates, core wires such as lead wires and coaxial cables, and electronic components. The object to be joined 23 having a metal joint 23a such as a chip has a metal joint 24a such as an organic substrate such as a rigid glass epoxy substrate or a flexible polyimide flexible substrate, a ceramic substrate, or a wafer. It joins to the predetermined position of the to-be-joined object 24 by ultrasonic vibration. The object 23 is held on the holding surface of the holding means 40 of the resonator 7, and the object 24 is placed on the upper surface of the stage 10.

  As shown in FIG. 1, the joining device 100 includes a joining mechanism 27, a mounting mechanism 28 having a stage 10 and a stage table 12, a position recognition unit 29, a transport unit 30, and a control device 31.

  The joining mechanism 27 includes a vertical drive mechanism 25 and a head portion 26. The vertical drive mechanism 25 moves up and down while guiding the resonator support portion 6 with the vertical guide 3 by the vertical drive motor 1 and the bolt / nut mechanism 2. To do. The joining mechanism 27 is coupled to the frame 34, and the frame 34 is connected to the gantry 35 by the four support columns 13 disposed so as to surround the periphery of the pressure center of the head portion 26. A part of the support column 13 and the frame 34 is not shown.

  The resonator support 6 is guided in the vertical direction by the head escape guide 5 and is connected to the bolt / nut mechanism 2 while being pulled by the self-weight counter 4 for canceling the self-weight. A head portion 26 having a resonator 7 is coupled to the resonator support portion 6.

  Further, the resonator support portion 6 is provided with a pressure sensor 32, and the pressure sensor 32 detects the pressure applied to the workpieces 23 and 24 sandwiched between the resonator 7 and the stage 10. The pressure applied to the objects 23 and 24 detected by the pressure sensor 32 is fed back to the control device 31, and the vertical drive mechanism 25 is controlled based on the feedback value, whereby both objects 23 and 24 are connected. The pressure applied to is controlled. The resonator support section 6 includes resonator section height detection means 36 formed by a linear sensor or the like, whereby the height of the head section 26 is detected.

  The head unit 26 coupled to the resonator support unit 6 includes a resonator 7, a vibrator 8, a holding unit 40 that holds the object to be bonded 23 by suction, a base unit 20, a first clamping unit 21, and a second clamping unit. And resonator support means 44.

  The resonator 7 resonates with the ultrasonic vibration generated by the vibrator 8 and has a wavelength of one resonance frequency so that the center position of the resonator 7 and both end positions are the maximum amplitude points. It is formed with a length. If comprised in this way, each position 1/4 wavelength away from the maximum amplitude point will correspond to the minimum amplitude point (nodal point). The resonator 7 is formed in a cylindrical shape having a circular cross section.

  The vibrator 8 is connected to one end of the resonator 7 coaxially with the central axis of the resonator 7. In addition, the vibrator 8 is controlled by the control device 31 to generate ultrasonic vibrations, whereby the resonator 7 vibrates in the direction of the central axis.

  The holding means 40 is attached to the lower surface of the outer periphery at the substantially central position of the resonator 7 that is the maximum amplitude point by an adhesive such as a thermosetting resin, and holds various objects to be bonded 23 on the holding surface. In addition, the holding means 40 includes a vacuum suction mechanism (not shown) so that the workpiece 23 can be sucked and held on the holding surface. Note that the configuration for holding the workpiece 23 is not limited to the vacuum suction mechanism, and any configuration that can hold the workpiece 23 such as an electrostatic chucking mechanism or a mechanical chuck mechanism may be used. There may be. Alternatively, the workpiece 23 may be held by the holding means 40 by directly attaching the workpiece 23 to the holding means 40.

  Further, the holding means 40 may be formed of a member other than metal, such as cemented carbide tungsten carbide, ceramic, diamond, etc., and the holding means 40 configured in this way is composed of an epoxy adhesive, Ni, Cu, It may be adhered to the resonator 7 with a metal braze such as Ag.

  Further, by forming a concave groove on the outer periphery of the minimum amplitude point of the resonator 7, a supported portion having an outer peripheral surface having a smaller diameter than the outer peripheral surface of the resonator 7 is formed, and is formed in a concave shape. The supported portions are clamped by the first clamp means 21 and the second clamp means 22 included in the resonator support means 44, so that the resonator 7 is supported by the resonator support means 44.

  Further, the base 20 of the resonator support means 44 is fixed to the resonator support section 6, and the resonator support section 6 is supported by the resonator support means 44 by being driven up and down by the vertical drive mechanism 25. The resonator 7 moves up and down, and the workpieces 23 and 24 are pressurized.

  In addition, if the holding means 40 is formed of glass, super hard tungsten carbide, ceramic, diamond, or the like having a relatively high hardness among the above materials, the resonator 7 is made of a material having excellent acoustic characteristics, such as a titanium alloy. It is good to form by. Further, if the holding means 40 is formed of a material having high hardness, the resonator 7 may be formed of an inexpensive material such as Al.

  The mounting mechanism 28 includes a stage 10 on which the workpiece 24 is placed, and a stage table 12 that moves the stage 10 in a horizontal plane substantially orthogonal to the vertical direction.

  The stage 10 includes a vacuum suction mechanism (not shown) for sucking and holding the workpiece 24 on the upper surface of the stage 10. Note that the configuration for holding the workpiece 24 is not limited to the vacuum suction mechanism, and any configuration that can hold the workpiece 24 such as an electrostatic chucking mechanism or a mechanical chuck mechanism. It may be. Further, the object to be bonded 24 may be simply placed on the stage 210.

  The stage table 12 includes a moving shaft that can be moved in parallel and rotationally. The stage table 12 moves the stage 10 relative to the head portion 26, whereby the object 24 to be bonded to the object 23 held by the holding means 40. Adjust the relative position. In this embodiment, the stage table 12 is controlled by the control device 31 based on the relative positional relationship of the alignment marks provided on the workpieces 23 and 24 read by the upper and lower mark recognition means 14 described later. The relative positions of the objects 23 and 24 are adjusted.

  The position recognition unit 29 is inserted between the workpieces 23 and 24 arranged to face each other, and the upper and lower mark recognition means 14 for optically reading the alignment marks for position recognition provided on the workpieces 23 and 24, respectively. And an amplitude detector 33 for detecting the amplitudes of the workpieces 23 and 24 and the resonator 7, and a recognition means moving table 15 for moving the vertical mark recognition means 14 and the amplitude detector 33 in the horizontal plane and in the vertical direction. ing. The upper and lower mark recognizing means 14 includes a well-known two-field optical system lens composed of a mirror and a prism, and objects to be joined 23 and 24 disposed above and below the two-field optical system lens. A CCD camera for imaging (not shown).

  The transport unit 30 includes a supply device 16 and a tray 17 that transport the workpiece 23, and a transport device 18 and a transport conveyor 19 that transport the workpiece 24.

  The control device 31 controls the vertical drive mechanism 25 to adjust the pressure applied to the workpieces 23 and 24 via the head portion 26 or adjust the voltage and current applied to the vibrator 8 to adjust the pressure. For example, the magnitude of ultrasonic vibration energy applied to the joints 23 and 24 is controlled. Further, the control device 31 controls the vertical drive mechanism 25 based on the detection signal of the height position of the head unit 26 by the resonator unit height detection means 36, and the height of the head unit 26 in the direction of arrow Z in FIG. Adjust the height. Further, the control device 31 includes an operation panel (not shown) for controlling the entire joining device 100.

(Joining process)
Next, in the bonding apparatus 100, a metal bonding portion formed of Cu on a glass epoxy substrate 124 (corresponding to the “organic substrate” of the present invention) provided with an electrode pattern 124a for electrical connection of Cu as a metal bonding portion. An example of a joining process for joining the lead frame 123 having 123a will be described.

  In this embodiment, as shown in FIG. 2A, a plurality of electrode patterns 124a for electrical connection having a thickness of about 15 μm are provided on the surface of a glass epoxy substrate 124 having a thickness of about 500 μm, which is one of the objects to be joined. It has been. As shown in FIG. 2B, between the electrode pattern 124a of the glass epoxy substrate 124 and the metal joint 123a of the lead frame 123 having a thickness of about 300 μm, which is the other object to be joined, is about 20 μm. The ultrasonic vibration is applied in a state where the foil-shaped conductive material 50 made of Al having a thickness is interposed, so that the electrode pattern 124a and the metal joint portion 123a are bonded via the foil-shaped conductive material 50, A power device or the like is formed.

  First, the glass epoxy substrate 124 and the foil-like conductive material 50 which are one object to be joined are supplied. The foil-like conductive material 50 is supplied to and held by the holding means 40 attached to the resonator 7 by a supply device (not shown). Further, the glass epoxy substrate 124 is supplied from the transfer conveyor 19 to the stage 10 by the transfer device 18 and held by suction.

  Next, the upper and lower mark recognizing means 14 is inserted by the recognizing means moving table 15 between the foil-like conductive material 50 and the glass epoxy substrate 124 held so that the respective joint surfaces face each other, and the foil held face-to-face. The relative positions of the conductive material 50 and the glass epoxy substrate 124 are detected. Then, based on the relative positional relationship between the foil-like conductive material 50 and the glass epoxy substrate 124 detected by the upper and lower mark recognizing means 14, the stage table 12 is moved in parallel and rotated with reference to the position of the foil-like conductive material 50. Thus, the position of the glass epoxy substrate 124 is adjusted, and the relative position adjustment between the foil-like conductive material 50 and the glass epoxy substrate 124 is performed.

  Subsequently, in a state where the relative positions of the foil-like conductive material 50 and the glass epoxy substrate 124 are aligned, the upper / lower mark recognizing unit 14 is retracted by the recognizing unit moving table 15 and the head unit 26 is moved by the upper / lower drive mechanism 25. Is started, and the foil-like conductive material 50 and the glass epoxy substrate 124 are brought close to each other. The foil-like conductive material 50 and the glass epoxy substrate 124 are connected to the resonator 7 and the stage 10 based on the detection signal from the pressure sensor 32 when the foil-like conductive material 50 and the electrode pattern 124a of the glass epoxy substrate 124 come into contact with each other. Is detected between the foil-like conductive material 50 and the glass epoxy substrate 124, and ultrasonic vibration is applied to the electrode pattern 124a of the glass epoxy substrate 124. The foil-like conductive material 50 is temporarily joined (step S1).

  At this time, the ultrasonic vibration energy derived from the current value and the voltage value applied to the vibrator 8 by the control device 31, the resonance amplitude of the resonator 7, the pressure applied to the foil-like conductive material 50 and the glass epoxy substrate 124, etc. Monitoring and control are performed.

  When the temporary bonding between the foil-like conductive material 50 and the electrode pattern 124a of the glass epoxy substrate 124 is completed, the adsorption of the foil-like conductive material 50 by the resonator 7 is released, and the head portion 26 is moved back upward. Subsequently, the lead frame 123, which is the other object to be joined, is supplied from the tray 17 to the holding means 40 attached to the resonator 7 by the supply device 16 and is sucked and held.

  Next, the upper and lower mark recognizing means 14 is inserted between the lead frame 123 and the glass epoxy substrate 124, which are held so that the respective joint surfaces face each other, by the recognizing means moving table 15, and the lead frame 123 held facing each other. The upper and lower mark recognition means 14 detects the relative position of the glass epoxy substrate 124. Then, based on the relative positional relationship between the lead frame 123 and the glass epoxy substrate 124 detected by the upper and lower mark recognizing means 14, the stage table 12 is moved in parallel and rotated with reference to the position of the lead frame 123, and the glass epoxy substrate is moved. The position of 124 is adjusted, and relative position adjustment between the lead frame 123 and the glass epoxy substrate 124 is performed (step S2).

  Subsequently, in a state where the relative positions of the lead frame 123 and the glass epoxy substrate 124 are aligned (the positions of the electrode pattern 124a and the metal joint 123a are aligned), the recognition means moving table 15 causes the upper / lower mark recognition means 14 to move. Is retracted, and the vertical drive mechanism 25 starts the descent of the head portion 26 so that the lead frame 123 and the glass epoxy substrate 124 are brought close to each other.

  Based on the detection signal from the pressure sensor 32 when the metal joint portion 123a of the lead frame 123 contacts the electrode pattern 124a of the glass epoxy substrate 124 to which the foil-like conductive material 50 is temporarily joined, the lead frame 123 and the glass When it is detected that the epoxy substrate 124 is sandwiched between the resonator 7 and the stage 10 via the foil-like conductive material 50, a predetermined pressing force is applied to the lead frame 123 and the glass epoxy substrate 124 and super The sonic vibration is applied, and the metal bonding portion 123a of the lead frame 123 is bonded to the electrode pattern 124a of the glass epoxy substrate 124 to which the foil-like conductive material 50 is temporarily bonded (step S3).

  At this time, similarly to the temporary bonding of the foil-like conductive material 50 to the electrode pattern 124a of the glass epoxy substrate 124, the ultrasonic wave derived from the current value and the voltage value applied to the vibrator 8 by the control device 31. Monitoring and control of vibration energy, resonance amplitude of the resonator 7, pressure applied to the lead frame 123 and the glass epoxy substrate 124, and the like are performed. In addition, the timing to end the bonding process is determined when the pressure, ultrasonic vibration energy, and bonding time necessary for bonding with a target bonding area are obtained in advance, and the respective values obtained in advance are reached. The bonding process may be terminated.

  In this embodiment, as an example, the oscillation frequency of the vibrator 8 is set to 40 kHz. However, the magnitude of the relative vibration amplitude between the lead frame 123 and the glass epoxy substrate 124 depends on the type (material) of the object to be joined. , Function, etc.), contact area and the like.

  When the joining of the lead frame 123 and the glass epoxy substrate 124 is completed and the joining process is completed, the suction of the lead frame 123 by the resonator 7 is released, and the head portion 26 is moved back upward. Finally, in a state where the lead frame 123 is bonded, the glass epoxy substrate 124 held on the stage 10 is discharged to the transfer conveyor 19 by the transfer device 18, and a series of bonding processes is completed. Note that the number of lead frames 123 to be bonded to the glass epoxy substrate 124 is not limited to one, and a plurality of lead frames 123 may be continuously bonded to the glass epoxy substrate 124. Further, the thickness of the glass epoxy substrate 124, the electrode pattern 124a, and the lead frame 123 (metal bonding portion 123a) is not limited to the above example. For example, the glass epoxy substrate 124 may be formed with a thickness of 50 to 1000 μm. The electrode pattern 124a can be formed to a thickness of 5 to 30 μm, and the lead frame 123 can be formed to a thickness of 10 to 1000 μm.

(Joint strength)
An example of the bonding strength of the lead frame 123 and the glass epoxy substrate 124 bonded as described above will be described.

  As shown in FIG. 4, if the foil-like conductive material 50 made of Al is not interposed between the metal joint portion 123a of the lead frame 123 and the electrode pattern 124a of the glass epoxy substrate 124, the peel strength is 1 pin. In contrast to 3N, when the foil-like conductive material 50 is interposed, the metal joint portion 123a of the lead frame 123 and the electrode pattern 124a of the glass epoxy substrate 124 are joined at a peel strength of 30N per pin.

(Other examples of joined objects (1))
Next, in the bonding apparatus 100, an electrode pattern 224a for electrical connection is provided by Cu or Au as a metal joint on the glass epoxy substrate 124 provided with an electrode pattern 124a for electrical connection by Cu or Au as a metal joint. An example of a bonding process for bonding the obtained flexible substrate 224 (corresponding to the “organic substrate” of the present invention) will be described with reference to FIGS. 5 and 6. FIG. 5 is a diagram showing an example of the objects to be joined, and FIG. 6 is a diagram showing an example of the joining strength.

  In another example (1), as shown in FIG. 5, an electrode pattern 124a made of Cu or Au for electrical connection is about 10 μm on the surface of a glass epoxy substrate 124 having a thickness of about 100 μm, which is one object to be joined. It is provided with thickness. And, as shown in the figure, between the electrode pattern 124a of the glass epoxy substrate 124 and the electrode pattern 224a of about 10 μm thickness of the flexible substrate 224 of about 100 μm thickness which is the other object to be joined, about 20 μm. The electrode patterns 124 a and 224 a are bonded to each other through the foil-like conductive material 50 by applying ultrasonic vibration with the Al foil-like conductive material 50 formed with a thickness of 5 mm. Since other configurations and operations are the same as those in the above-described example, description of the configurations and operations is omitted.

  Next, an example of the bonding strength between the flexible substrate 224 and the glass epoxy substrate 124 will be described.

  As shown in FIG. 6, if the foil-like conductive material 50 made of Al is not interposed between the electrode pattern 224a made of Cu of the flexible substrate 224 and the electrode pattern 124a made of Cu of the glass epoxy substrate 124, While the peel strength is 2N per pin, when the foil-like conductive material 50 is interposed, the electrode pattern 224a of the flexible substrate 224 and the electrode pattern 124a of the glass epoxy substrate 124 are peeled at 15N per pin. Various sensors such as a piezoelectric sensor and a flexible board connector are formed, and the boards are electrically connected to each other.

  In addition, as shown in FIG. 6, the foil-like conductive material 50 made of Al must be interposed between the electrode pattern 224a made of Au on the flexible substrate 224 and the electrode pattern 124a made of Au on the glass epoxy substrate 124. For example, the peel strength is 10 N per pin, whereas if the foil-like conductive material 50 is interposed, the electrode pattern 224 a of the flexible substrate 224 and the electrode pattern 124 a of the glass epoxy substrate 124 have a peel strength of 18 N per pin. And are joined.

  The thicknesses of the flexible substrate 224 and the electrode pattern 224a are not limited to the above example. For example, the glass epoxy substrate 124 is formed with a thickness of 10 to 500 μm, and the electrode pattern 124a is formed with a thickness of 5 to 30 μm. In this case, the flexible substrate 224 can be formed with a thickness of 10 to 500 μm, and the electrode pattern 224a can be formed with a thickness of 5 to 30 μm.

  In this example, the flexible substrate 224 is bonded to the glass epoxy substrate 124, but the flexible substrates 224 may be bonded to each other.

(Other examples of workpieces (2))
Next, in the bonding apparatus 100, an example of a bonding process for bonding a core wire 223 (metal bonding portion) made of Cu to a glass epoxy substrate 124 in which an electrode pattern 124a for electrical connection is provided by Cu as a metal bonding portion. This will be described with reference to FIGS. 7A and 7B are diagrams showing an example of an object to be joined, where FIG. 7A is a perspective view, FIG. 7B is an enlarged view of a main part, and FIG. 8 is a diagram showing an example of bonding strength.

  In another example (2), as shown in FIG. 7A, a plurality of electrode patterns 124a made of Cu for electrical connection are provided on the surface of a glass epoxy substrate 124 which is one of the objects to be joined. And as shown in the figure (b), in the state which interposed the foil-shaped electrically conductive material 50 made from Al between the electrode pattern 124a of the glass epoxy board | substrate 124, and the core wire 223 which is the other thing to be joined. By applying ultrasonic vibration, the electrode pattern 124 a and the core wire 223 are joined via the foil-like conductive material 50. Since other configurations and operations are the same as those in the above-described example, description of the configurations and operations is omitted.

  Next, an example of the bonding strength between the core wire 223 and the glass epoxy substrate 124 will be described.

  As shown in FIG. 8, bonding is not performed unless the foil-like conductive material 50 made of Al is interposed between the core wire 223 made of Cu and the electrode pattern 124a made of Cu on the glass epoxy substrate 124. In contrast, if the foil-like conductive material 50 is interposed (peel strength is 0 N per pin), the core wire 223 and the electrode pattern 124 a of the glass epoxy substrate 124 are bonded with a peel strength of 8 N per pin.

  In this example, the core wire 223 is bonded to the glass epoxy substrate 124, but the core wire 223 may be bonded to the flexible substrate 224. Further, as described above, the thickness of the glass epoxy substrate 124, the electrode pattern 124a, the flexible substrate 224, the electrode pattern 224a, the thickness of the core wire 223, and the like may be set as appropriate.

(Other examples of joined objects (3))
Next, in the bonding apparatus 100, the electrode pattern 124a formed of Cu is formed of Cu on the glass epoxy substrate 124 provided with the metal bonding portion where the Ni plating 124a1 and the Au plating 124a2 for preventing oxidation are provided. An example of a joining process for joining the lead frame 123 on which the Ni plating 123a1 and the Au plating 123a2 for preventing oxidation are joined to the metal joining portion 123a will be described with reference to FIG. FIG. 9 is an enlarged view of a main part showing an example of an object to be joined, in which (a) shows a state before joining, and (b) shows a state after joining.

  In another example (3), as shown in FIG. 9A, an electrode pattern for electrical connection in which a Ni-plated 124a1 and an Au-plated 124a2 are applied to the surface of a glass epoxy substrate 124, which is one of the objects to be joined. 124a is provided. Then, as shown in FIG. 5B, between the electrode pattern 124a (Au plating 124a2) of the glass epoxy substrate 124 and the metal bonding portion 123a (Au plating 123a2) of the lead frame 123 which is the other object to be joined. In addition, by applying ultrasonic vibration with the Al foil-like conductive material 50 interposed, the metal joint portion 123a (Au plating 123a2) and the electrode pattern 124a (Au plating 124a2) become foil-like conductive material. 50 is joined. Since other configurations and operations are the same as those in the above-described example, description of the configurations and operations is omitted.

  Note that the thickness of the glass epoxy substrate 124, the electrode pattern 124a, the lead frame 123, and the like may be appropriately set as described above. In all of the above examples, in order to prevent oxidation or improve electrical conductivity, plating such as Ni or Au may be applied to the metal joint.

(Other examples of foil-like conductive material (1))
Next, another example of the foil-like conductive material will be described with reference to FIG. FIG. 10 is a diagram illustrating an example of a foil-like conductive material. As shown in FIG. 10, the foil-shaped conductive material 150 in this example includes a plurality of openings 150 b provided on the foil-shaped tape material 150 a made of the same material as the foil-shaped conductive material 150 according to the shape of the glass epoxy substrate 124. A plurality of island patterns are arranged in accordance with the positions of the plurality of electrode patterns 124a.

  Further, as shown in FIG. 10, the foil-like conductive material 150 is formed continuously at the tip of the bridging piece formed in a taper shape in the opening 150b of the tape material 150a. When an external force such as sonic vibration is applied, the foil-like conductive material 150 is formed so as to be easily detached from the tip of the bridging piece. Since other configurations and operations are the same as those in the above-described example, description of the configurations and operations is omitted by assigning the same reference numerals.

  If comprised in this way, the glass epoxy board | substrate 124 and one of the some opening 150b formed in the tape material 150a will be aligned, and on each electrode pattern 124a, the opening 150b will be via a bridge piece. Each foil-like conductive material 150 formed continuously is arranged, and ultrasonic vibration is sequentially applied to each foil-like conductive material 150 arranged on each electrode pattern 124a, whereby the foil-like conductive material 150 is made to correspond to each electrode. Temporary joining can be performed continuously to the pattern 124a.

  In addition, each foil-like conductive material 150 is continuously formed in the opening 150b through a bridge piece formed in a taper shape so that it can be easily detached. When the ultrasonic vibration is applied, each foil-like conductive material 150 is easily detached from the opening 150b. Therefore, the step of cutting the bridging piece and separating the electrode pattern 124a is unnecessary, and each foil-like conductive material is efficiently removed. The conductive material 150 can be temporarily bonded to each electrode pattern 124a.

  Further, when the foil-like conductive material 150 is temporarily joined to the plurality of electrode patterns 124a of the glass epoxy substrate 124 newly held on the stage 10, the foil among the plurality of openings 150b formed in the tape material 150a. The foil-like conductive material 150 can be temporarily joined to the electrode pattern 124a in the same manner by aligning the opening 150b in which the temporary joining of the conductive material 150 to the electrode pattern 124a is not completed with the glass epoxy substrate 124.

  Note that the tape material 150a may be wound and stored on a reel (not shown) and temporarily bonded to the electrode pattern 124a of the foil-like conductive material 150 while pulling out the tape material 150a as necessary.

(Other examples of foil-like conductive material (2))
Next, another example of the foil-like conductive material will be described with reference to FIG. FIG. 11 is a diagram illustrating an example of a foil-like conductive material. As shown in FIG. 11, the foil-like conductive material 250 in this example includes a plurality of film-like tape materials 250 a formed of a resin material according to the shape and position of each electrode pattern 324 a of the flexible substrate 324. It arrange | positions at each of opening (illustration omitted).

  The foil-like conductive material 250 is formed so that the foil-like conductive material 250 is easily detached from the opening of the tape material 250a when an external force such as ultrasonic vibration is applied to the foil-like conductive material 150. Since other configurations and operations are the same as those in the above-described example, description of the configurations and operations is omitted by assigning the same reference numerals.

  With this configuration, the flexible substrate 324 and one of the group of the foil-like conductive materials 250 formed on the tape material 250a are aligned, and each foil-like conductive material 250 is placed on each electrode pattern 324a. And applying ultrasonic vibration to the plurality of foil-like conductive materials 250 arranged on each electrode pattern 324a makes it possible to temporarily bond the plurality of foil-like conductive materials 250 to each electrode pattern 324a simultaneously. .

  Each foil-like conductive material 250 is provided in the opening of the tape material 250a so as to be easily detached, and each foil-like conductive material 250 is applied with ultrasonic vibration to each foil-like conductive material 250 at the time of temporary bonding. Since the conductive material 250 is easily detached from the opening, there is no need to separate the foil-shaped conductive material 250 from the tape material 250a, and each foil-shaped conductive material 250 can be efficiently temporarily bonded to each electrode pattern 324a. .

  Further, when the foil-like conductive material 250 is temporarily joined to the plurality of electrode patterns 324a of the flexible substrate 324 newly held on the stage 10, a group of the plurality of foil-like conductive materials 250 formed on the tape material 250a. By aligning a new group of them to the flexible substrate 324, the foil-like conductive material 250 can be temporarily joined to the electrode pattern 324a in the same manner.

  Note that the tape material 250a may be wound and stored on a reel (not shown) and temporarily joined to the electrode pattern 324a of the foil-like conductive material 250 while pulling out the tape material 250a as necessary.

  As described above, according to this embodiment, when joining the objects 23 and 24 that are difficult to be joined only by applying ultrasonic vibration, the metal joint portions 23a and 24a of both the objects 23 and 24 are joined. In the meantime, by applying ultrasonic vibration through the metallic foil-like conductive material 50, even if the workpieces 23, 24 are deformed, the foil shape interposed between the metal joints 23a, 24a. There is no possibility that a gap or the like is generated at the bonding interface by the conductive material 50, and the foil-shaped conductive material 50 prevents the metal joint portions 23 a and 24 a from coming into direct contact with each other. The ultrasonic vibration is reliably applied to the bonding interface formed by the contact between the two metal joints 23 a and 24 a, and the two metal joints 23 a and 24 a are securely joined via the foil-like conductive material 50. So metal bonding 23a, and if the welded article 23 having 24a can be satisfactorily bonded to.

  Further, the two metal joints 23a are joined by ultrasonic vibration to one object to be joined 24 in which the foil-like conductive material 50 is temporarily joined to the metal joint 24a by ultrasonic vibration. , 24a, the ultrasonic vibration can be applied in a state where the foil-like conductive material 50 is reliably interposed.

  In addition, it is difficult to bond by simply applying ultrasonic vibration, and the object to be bonded provided with the electrode patterns 124a and 224a for electrical connection as the metal bonding portion is securely bonded to the glass epoxy substrate 124 or the flexible substrate 224. Can do.

  In addition, it is difficult to join only by applying ultrasonic vibrations, and it is possible to reliably join an object to be joined including the lead frame 123 or the core wire 223.

  Further, when joining the objects 23 and 24 that are difficult to be joined only by applying ultrasonic vibration, the metal foil-like conductive material 50 is interposed between the metal joints 23a and 24a of the objects 23 and 24. By applying ultrasonic vibration in a state where the metal is bonded, it is possible to satisfactorily bond the objects to be bonded 23 and 24 having the metal bonding portions 23a and 24a without melting the solder or using the heating together. For example, an object to be bonded such as a glass epoxy substrate whose shape and characteristics change by giving a thermal history exceeding the glass transition temperature can be bonded at a low temperature not higher than the glass transition temperature. Moreover, it can also join without heating at normal temperature.

The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the gist of the invention. The foil-like conductive material 50 can be easily formed by any one of Ag, Au, Cu, Ni, foamed Ni, Pt, Cr, Pd, In, and solder. The same effect as when the foil-like conductive material 50 is formed can be obtained.
The Further, by forming the foil-like conductive material 50 from a metal softer than the metal joint provided on the object to be joined, the metal-joined portion in contact with the foil-like conductive material 50 and the foil-like conductive material 50 are ultrasonic. Since it becomes easy to be joined by vibration, the metal joining portions can be more favorably joined via the foil-like conductive material 50.

  In addition, when the foil-like conductive material 50 is formed of solder, the metal joints can be bonded to each other via the foil-like conductive material 50 by applying a flux to the foil-like conductive material 50. . Further, when the foil-like conductive material 50 is formed of solder, if the metal joint portion is formed of Au or the metal joint portion is plated with Au, Au is soldered at the time of joining. Therefore, the metal joints can be joined well.

  Moreover, if the film thickness of the foil-like conductive material 50 is formed with a practical thickness of 5 to 1000 μm, depending on the material, size, and thickness of the object to be joined, and the material, size, and thickness of the metal joint portion. Good.

  In addition, the kind of the object to be joined having the metal joint portion is not limited to the above example, and any material can be used as long as the material can be joined by ultrasonic vibration, such as a ceramic substrate or a wafer. Bonding by ultrasonic vibration may be performed with the object to be bonded.

DESCRIPTION OF SYMBOLS 23 ... To-be-joined object 23a ... Metal joining part 24 ... To-be-joined object 24a ... Metal joining part 50,150,250 ... Foil-shaped electrically conductive material 123 ... Lead frame 123a ... Metal joining part 124 ... Glass epoxy board (organic board | substrate)
124a ... Electrode pattern 223 ... Core wire (metal joint)
224, 324 ... Flexible substrate (organic substrate)
224a, 324a ... electrode pattern

Claims (6)

In the joining method of joining the objects to be joined having a metal joint by applying ultrasonic vibration,
One metal foil-like conductive material is temporarily bonded to the electrode pattern for electrical connection provided as the metal bonding portion on the rigid or flexible organic substrate as one of the objects to be bonded by applying ultrasonic vibration. Process,
The metal bonding portion of the other object to be bonded is connected to the electrode pattern on which the foil-like conductive material of the organic substrate is temporarily bonded, and the metal bonding of the electrode pattern of the organic substrate and the other object to be bonded is performed. A step of applying ultrasonic vibration in a state of interposing the foil-like conductive material between the parts, and joining,
In the temporary joining step,
A tape material provided with the foil-like conductive material is prepared, and the necessary number of the foil-like conductive materials are transferred from the tape material to the electrode pattern of the organic substrate and temporarily joined in one bonding step. And
The thickness of the said foil-like electrically conductive material is thicker than the thickness of the said electrode pattern of the said organic substrate, The joining method characterized by the above-mentioned . In the temporary bonding step, the foil-like conductive material is transferred from the tape material to the electrode pattern of the one organic substrate and temporarily bonded. In the temporary bonding step to be executed next, the other organic The bonding method according to claim 1, wherein a new foil-shaped conductive material is transferred from the tape material to the electrode pattern of the substrate and temporarily bonded.   The joining method according to claim 1, wherein the foil-like conductive material is made of any one of Al, Ag, Au, Cu, Ni, Pt, Cr, Pd, In, and solder.   The joining method according to any one of claims 1 to 3, wherein a film thickness of the foil-like conductive material is 5 to 1000 µm. The other object to be bonded, the bonding method according to any of claims 1 to 4, characterized in that a lead frame. The other object to be bonded, the bonding method according to any of claims 1 to 4, characterized in that a core wire.

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