JP2011005500A - Substrate fixing table and ultrasonic welding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate fixing table for mounting a welding object having a structure for preventing degradation in welding strength between the welding object and a material to be welded.SOLUTION: The substrate fixing table 5 is formed of a material (aluminum or steel) having the acoustic impedance equivalent to that of a glass material as a material having the acoustic impedance capable of allowing the vibration in a glass substrate 3 to be transmitted as the transmitted wave. The size of an upper surface area of the glass substrate 3 is set so that the margin width Dt forming the shortest distance from an outer peripheral end of the glass substrate 3 to an end of the substrate fixing table 5 when mounting the glass substrate 3 on a glass substrate mount-scheduled area R3 becomes the length of ≥1/4 of the plane wavelength transmitting in the glass substrate 3 consisting of glass material.

Description

  The present invention relates to a substrate fixing table used in an ultrasonic bonding apparatus.

  Ultrasonic bonding device as a device for connecting the wire connection part of the terminal box and the wire terminal of the lead lead wire of the electric wire, or as a device for joining a material to be joined such as a lead wire for external lead on the joining target part of an electronic device or the like There is. For example, the ultrasonic bonding apparatus mounts an electric wire terminal (material to be bonded) on an electric wire connecting portion (bonding target portion) and applies ultrasonic vibration to perform bonding. In ultrasonic bonding using ultrasonic vibration by an ultrasonic bonding device, frictional heat is generated at the bonding interface by applying stress in the vertical direction to the bonding interface and repeated stress due to high vibration acceleration in the parallel direction. Let Thereby, the atoms of the materials to be joined can be diffused and joined. Such an ultrasonic bonding apparatus generally performs an ultrasonic bonding operation by placing a bonding target portion on a table called an anvil. An ultrasonic bonding apparatus having the above table is disclosed in, for example, Patent Document 1.

JP 2006-107882 A

  However, the table in the ultrasonic bonding apparatus has a problem that the bonding strength between the bonding target portion and the material to be bonded is deteriorated as a result of attenuation of ultrasonic vibration due to the reflected wave generated from the bonding target portion. there were.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a substrate fixing table for mounting a bonding target portion having a structure that does not deteriorate the bonding strength between the bonding target portion and the material to be bonded.

  According to a first aspect of the present invention, the substrate fixing table pressurizes the material to be bonded disposed on the surface of the thin film substrate made of the first material from above using an ultrasonic bonding tool and ultrasonic waves. A substrate fixing table made of a second material that is used in an ultrasonic bonding apparatus that applies vibration to bond the material to be bonded onto the surface of the thin film substrate, and has the thin film substrate mounted thereon, The substrate fixing table has a fixed mounting means capable of fixing and mounting the thin film substrate on a surface thereof, and the second material is a vibration in the thin film substrate when the thin film substrate is fixedly mounted by the fixed mounting means. Including a material having an acoustic impedance capable of propagating as a transmitted wave, and the shortest distance from the outer peripheral end of the thin film substrate to the end of the substrate fixing table when the thin film substrate is fixedly mounted is Characterized in that it is set to 1/4 or more the length of the plane wave traveling through the inside of the membrane substrate.

  In the ultrasonic bonding tool according to the present invention, the surface portion in contact with the material to be bonded in the tip portion has a plurality of flat portions formed separately from each other and a plurality of concave portions formed between the plurality of flat portions. The plurality of flat portions 10 have a flatness of 2 μm or less.

  For this reason, by the ultrasonic bonding method using the ultrasonic bonding apparatus having the ultrasonic bonding tool of the present invention, for example, the material to be bonded without any trouble on the surface of a thin film substrate such as a glass substrate having a plate thickness of 2 mm or less. The effect which can be joined is produced.

It is a top view which shows typically the upper surface structure of the board | substrate fixed table which is Embodiment 1 of this invention. FIG. 4 is a cross-sectional view schematically showing an ultrasonic bonding state when a glass substrate is actually mounted on a glass substrate mounting scheduled area of the substrate fixing table of the first embodiment. FIG. 3 is a plan view schematically showing a state when a glass substrate is mounted on a glass substrate mounting scheduled area of the substrate fixing table of the first embodiment. 6 is a graph showing an effect obtained by using the substrate fixing table of the first embodiment. It is explanatory drawing which shows the condition which mounted the glass substrate on the board | substrate fixed table which is Embodiment 2 of this invention.

<Embodiment 1>
1 is a plan view schematically showing an upper surface structure of a substrate fixing table according to Embodiment 1 of the present invention. As shown in the figure, the substrate fixing table 5 has an upper surface area sufficiently larger than the glass substrate mounting scheduled area R3.

  The glass substrate mounting scheduled region R3 means a virtual plane region on which the glass substrate 3 which is a thin film substrate having a plate thickness of about 0.7 to 2.0 mm and is mounted on the substrate fixing table 5 is mounted. Further, the lead wire bonding planned region R2 means a virtual plane region where the lead wire 2 that is actually a bonding member is bonded on the glass substrate 3 mounted on the glass substrate mounting planned region R3.

  The substrate fixing table 5 selectively distributes a plurality of (five in FIG. 1) suction pads 31 in the horizontal direction in the figure in the central region (first suction region) of the glass substrate mounting scheduled region R3 in the horizontal direction in the figure. Provided. Furthermore, the substrate fixing table 5 is provided with a plurality of fine suction grooves 32 (or suction holes are possible) along the lead wire joining planned region R2 in a region (second suction region) in the vicinity of the lead wire joining planned region R2. ing.

  FIG. 2 shows a chip portion at the tip in a state where the glass substrate 3 is actually mounted on the glass substrate mounting planned region R3 of the substrate fixing table 5 and the lead wire 2 is arranged on the lead wire bonding planned region R2 of the glass substrate 3. It is sectional drawing which shows typically the ultrasonic joining condition by the tool 1 for ultrasonic joining which has 1c. 2 corresponds to the AA cross section of FIG.

  As shown in the figure, a glass substrate 3 is mounted on a substrate fixing table 5 having a plate thickness of 5 mm or more, and the plate thickness is 0.1 to 0. An external lead wire 2 (material to be joined) made of aluminum of about 2 mm is disposed. Then, a vertical pressing force is applied to the bonding surface with the lead wire 2 via the chip portion 1c of the ultrasonic bonding tool 1, and the ultrasonic bonding tool 1 is ultrasonically vibrated in the horizontal direction to bond the bonding surface. The lead wire 2 and the glass substrate 3 are solid-phase bonded at the bonding interface between the lead wire 2 and the glass substrate 3 by executing an ultrasonic bonding operation that greatly deforms the wire.

  As shown in FIGS. 1 and 2, the glass substrate 3 has a substrate fixing table 5 by a suction function from a plurality of suction pads 31 (first fixing means) provided in a plurality of selectively formed openings 30. Fixed above. For example, when the glass substrate 3 has a 600 × 1200 mm planar region and has a composite structure in which Cr (chromium) or Mo (molybdenum) is formed on the surface thereof, it is about 5 mm due to a difference in heat treatment history and thermal expansion coefficient. There is a possibility of warping.

  However, this warp can be corrected with high accuracy by the suction function from the plurality of suction pads 31 (following the substrate fixing table 5).

  In addition, as shown in FIG. 1 and FIG. 2, by firmly adsorbing from the back surface of the glass substrate 3 by a plurality of adsorption grooves 32 (second fixing means) formed in the vicinity of the lead wire joining planned region R2. The vibration of the glass substrate 3 when the ultrasonic vibration is applied to the chip portion 1c can be suppressed. For this reason, the ultrasonic vibration of the bonding surface of the lead wire 2 can be efficiently changed to bonding energy, and the lead wire 2 can be firmly bonded to the glass substrate 3.

  Furthermore, since the vibration function (resonance) in which the glass substrate 3 and the substrate fixing table 5 are integrated can be exhibited by the suction function by the plurality of suction pads 31 and the plurality of suction grooves 32, the glass substrate 3 alone Damage to the glass substrate 3 due to resonance can be effectively suppressed.

  Instead of the suction pad 31, an electrostatic suction means may be used, and the suction hole or the metal foam plate described above may be used instead of the suction groove 32.

  FIG. 3 is a plan view schematically showing a state when the glass substrate 3 is mounted on the glass substrate mounting planned region R3 of the substrate fixing table 5. FIG. Although not shown in FIG. 3, the substrate fixing table 5 is provided with first and second fixing means by the plurality of suction pads 31 and the plurality of suction grooves 32 shown in FIGS. 1 and 2.

The glass substrate 3 is made of a glass material (quartz: acoustic impedance = 13.1 × 10 ⁶ Pa · s / m ³ ). The substrate fixing table 5 is made of a material having an acoustic impedance equivalent to that of a glass material as a material having an acoustic impedance that allows vibration in the glass substrate 3 to propagate as a transmitted wave. For example, aluminum (acoustic impedance = 17.3 × 10 ⁶ Pa · s / m ³ ) or iron (49.9 × 10 ⁶ Pa · s / m ³ ) is used as a constituent material of the substrate fixing table 5. have.

  As shown in FIG. 3, the size of the upper surface region of the glass substrate 3 includes the glass substrate 3, and the substrate fixing table from the peripheral edge of the glass substrate 3 when the glass substrate 3 is mounted on the glass substrate mounting planned region R <b> 3. The marginal width Dt that is the shortest distance to the end of 5 is a plane wavelength that propagates inside the glass substrate 3 made of a glass material (for example, when the ultrasonic vibration is 20 kHz, the plane wavelength that propagates in the glass is about 500 mm). ) Has a top surface area feature that is set to a length of 1/4 (125 mm) or more.

  Hereinafter, effects based on the material feature and the upper surface region feature of the substrate fixing table 5 will be described. When performing an ultrasonic bonding operation using the ultrasonic bonding tool 1 by the ultrasonic bonding apparatus, an input wave due to ultrasonic vibration is transmitted to the inside of the glass substrate 3. At this time, conventionally, the ultrasonic wave on the lead wire joining planned region R2 is attenuated by the combined wave of the reflected wave from the end of the glass substrate 3 and the input wave, and the lead wire 2 and the glass substrate 3 are attenuated. There was a risk of weakening the joint strength.

  On the other hand, since the substrate fixing table 5 of the first embodiment has the material characteristics as described above, the glass substrate 3 is fixedly mounted on the substrate fixing table 5 by the fixing mounting means including the first and second fixing means. In this case, the vibration in the glass substrate 3 can be propagated in the substrate fixing table 5 as a transmitted wave.

  As a result, the reflected wave reduction effect that the reflected wave at the peripheral edge of the glass substrate 3 can be reduced can be exhibited. This reflected wave reduction effect can be more prominently exhibited by the above-described upper surface region feature.

  FIG. 4 is a graph showing the effect of using the substrate fixing table 5 of the first embodiment. In the figure, the position is a graph showing the relationship between the position (1 unit = 30 mm) in the longitudinal direction D1 (total length 1200 mm) of the glass substrate 3 and the peeling force (unit gf) between the glass substrate 3 and the substrate fixing table 5. It is.

  As shown in FIG. 4, the peeling force L1 according to the first embodiment in which the glass substrate 3 is fixedly mounted on the substrate fixing table 5 is superior to the peeling force L2 due to the conventional arrangement in which the reflected wave is generated by the glass substrate 3 alone. It can be seen that the difference is particularly prominent at the end of the glass substrate 3 in the longitudinal direction D1.

  As described above, the substrate fixing table 5 according to the first embodiment has the above-described material characteristics, upper surface region characteristics, and fixed mounting means using the first and second fixing means. The glass substrate 3 can be mounted in a fixed manner.

  As a result, the ultrasonic bonding apparatus having the substrate fixing table 5 according to the first embodiment removes the influence of the reflected wave generated at the end of the lead wire 2 when the lead wire 2 is ultrasonically bonded to the glass substrate 3. Thus, there is an effect that the lead wire 2 can be bonded onto the surface of the glass substrate 3 without weakening the bonding strength.

<Embodiment 2>
FIG. 5 is an explanatory view showing a situation in which the glass substrate 3 is mounted on the substrate fixing table 6 according to the second embodiment of the present invention. (A) of the figure is a top view, and (b) is a BB sectional view of (a).

  As shown in the figure, the substrate fixing table 6 includes a table main body 6a, an elastic portion 18, a pressing plate 19 and screws 20 for fixing the glass substrate 3 mounted on the glass substrate mounting planned region R3 from above. And third fixing means. The elastic part 18 is composed of an elastic body such as rubber. Although not shown in FIG. 5, a means equivalent to the first and second fixing means of the first embodiment by the plurality of suction pads 31 and the plurality of suction grooves 32 shown in FIGS. 1 and 2 is a table. It is provided in the main body 6a.

  The holding plate 19 is formed to extend in the short direction of the glass substrate mounting planned region R3 in the vicinity of both ends in the longitudinal direction D1 of the glass substrate mounting planned region R3, and the outer end 19b is fixed to the table body 6a by screws 20. Yes. An elastic portion 18 is provided on the lower surface and the inner side surface of the main portion 19 a of the presser plate 19. As shown in FIG. 4 (b), the glass substrate 3 is inserted into the recessed portion formed by the elastic portion 18 and the table body 6a while the both ends thereof are in close contact with the end side surface and the end top surface of the elastic portion 18. It is fixed in the presser plate 19 with good stability.

  As described above, the substrate fixing table 6 according to the second embodiment is not limited to the first and second fixing means according to the first embodiment, but the third fixing means (the elastic portion 18, the pressing plate 19 and the fixing plate). By fixing the glass substrate 3 to the table body 6a more firmly with the screws 20), there is an effect that the bonding strength of the lead wire 2 to the surface of the glass substrate 3 can be further stabilized.

  In addition, as a result of the vibration energy at the end of the glass substrate 3 being attenuated by the elastic body constituting the elastic portion 18, the effect of suppressing the generation of reflected waves can be achieved.

<Others>
In the embodiment described above, the single-piece structure of the glass substrate 3 is shown as the thin film substrate. However, a conductive metal film layer such as Cr (chromium) or Mo (molybdenum), ITO, Of course, the present invention can also be applied to a composite structure including a glass substrate 3 on which conductive oxide layers such as ZnO and SnO are laminated, as in the case of the glass substrate 3 alone.

  Furthermore, even if the substrate is made of another constituent material such as a silicon substrate or a ceramic substrate, the present invention can be used as a thin film substrate of the above-described unit structure or composite structure in place of the glass substrate 3 if the thickness is 2 mm or less. Can be applied.

  5,6 Substrate fixing table, 6a Table body, 18 elastic part, 19 presser plate, 20 screws, 31 suction pad, 32 suction groove.

Claims (4)

The material to be bonded disposed on the surface of the thin film substrate made of the first material is pressurized from above using an ultrasonic bonding tool and ultrasonic vibration is applied to the material on the surface of the thin film substrate. A substrate fixing table used in an ultrasonic bonding apparatus for bonding materials to be bonded, and made of a second material on which the thin film substrate is mounted,
The substrate fixing table has fixed mounting means capable of fixing and mounting the thin film substrate on the surface thereof,
The second material includes a material having an acoustic impedance that allows vibration in the thin film substrate to propagate as a transmitted wave when the thin film substrate is fixedly mounted by the fixed mounting means.
The shortest distance from the outer peripheral end of the thin film substrate to the end of the substrate fixing table when the thin film substrate is fixedly mounted is set to a length of 1/4 or more of the plane wavelength transmitted through the thin film substrate. Characterized by
Board fixing table. The substrate fixing table according to claim 1,
The fixed mounting means is
A first fixing means which is provided in a first adsorption region in a region where the thin film substrate is to be mounted, and which fixes the thin film substrate by an adsorption action by a plurality of adsorption units;
The thin film substrate is fixed by an adsorption action by a plurality of concave portions provided in a second adsorption region in the vicinity of the planned bonding region where the material to be bonded outside the first adsorption region is bonded in the planned mounting region. Second fixing means,
Board fixing table. The substrate fixing table according to claim 1 or 2,
The fixed mounting means is
Third mounting means capable of fixing the thin film substrate from above via an elastic body after mounting the thin film substrate on the planned mounting region,
Board fixing table. The material to be bonded disposed on the surface of the thin film substrate made of the first material is pressurized from above using an ultrasonic bonding tool and ultrasonic vibration is applied to the material on the surface of the thin film substrate. An ultrasonic bonding apparatus for bonding workpieces,
A substrate fixing table made of a second material on which the thin film substrate is mounted;
The substrate fixing table includes the substrate fixing table according to any one of claims 1 to 3.
Ultrasonic bonding device.

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