JP5175434B2 - Support device for ultrasonic flexural vibrator - Google Patents

Description

  The present invention supports an ultrasonic flexural vibrator (hereinafter simply referred to as a flexural vibrator) used in an ultrasonic processing machine that vibrates (joins, cuts, polishes, etc.) semiconductor integrated circuits, metals, plastics, ceramics, and the like. Relates to the device.

Conventionally, the invention of Patent Document 1 is known as an ultrasonic bending vibration device.
In the above prior art, a conical recess is formed in the vibration node (see nodes N4 to N7 in FIG. 7 of Patent Document 1) of the outer peripheral surface of the flexural vibrator, and the pointed bolt screwed into the recess from the casing. The ultrasonic processing is performed by an ultrasonic vibration device fixed to the casing by contacting the surface.

  However, the above-described bending vibration member is held by a structure in which the point of the node on the outer peripheral surface of the vibration member and the casing are coupled and fixed with a pointed bolt, so that the bolt is against the axial pressure of the bending vibration member. Due to shear stress, there is a problem that the tip positioning accuracy and rigidity of the flexural vibrator are lacking.

  In addition, when the flexural vibration body performs composite flexural vibration, the stationary part in the vibration node exists only on the central axis of the vibration body, and the outer peripheral surface of the vibration body also vibrates. There is no fixed part.

  Further, when the composite flexural vibrator is supported on the side close to the outer surface through which the nodal line of the vibrator passes, the support surface near the outer surface of the vibrator has a rotational direction centering on the nodal line of vibration passing through the axis. Due to vibration, when the rigidity of the support portion is increased, another problem that vibration loss on the support surface increases is derived.

For this reason, when supporting the flexural vibrator constituting the ultrasonic processing machine, a support device that is a support having a high rigidity and a small vibration loss at the support portion has been desired.
JP-A-2-203972

  Accordingly, the present invention provides a support device for an ultrasonic processing machine for an ultrasonic processing machine that supports a flexural vibrator with a high rigidity but has little vibration loss at the support and high tip positioning accuracy. Doing that is the task.

The support device of the present invention, which has been made for the purpose of solving the above-mentioned problems, is a support device (hereinafter referred to as a support tool) that flexures and vibrates a flange installed at a vibration abdomen of an ultrasonic flexural vibrator at the same resonance frequency as the ultrasonic flexural vibrator. A support device for an ultrasonic flexural vibrator held by a resonance support tool, wherein the support tool uses a flange contact surface of the support tool as a vibration abdomen of the support tool, and a vibration node of the support tool. This is characterized in that a fixed end is provided .

  The support device of the present invention has been completed based on the knowledge that the vibration of the flexural vibrator can be supported with low loss by holding the flange installed on the abdomen of the vibration with a resonant support. Is.

That is, the invention of claim 1 is a support device for holding a flange installed on the abdomen of the flexural vibrator with a resonance support, and the invention of claim 2 is for connecting one end of the resonance support in the invention of claim 1 to A support device having a structure in which the resonance support member is connected to a fixed end at a vibration node of the resonance support tool. adjusted to a support device for a structure supporting the knuckles of the resonant support, the invention of claim 4, the expansion of the resonant support in the invention of claim 1 in a circular cone or annular disc-shaped This is a support device having a structure.

  The present invention constitutes a support device for an ultrasonic flexural vibrator as a structure in which a flange installed on the vibration abdomen of the ultrasonic flexural vibrator is held by a support that flexes and vibrates at the same resonance frequency as the ultrasonic flexural vibrator. As a result, a basic effect can be obtained in which a support having a high rigidity can be realized, while vibration loss in the support portion can be slightly suppressed.

Prior to the description of the embodiment of the support device of the present invention, the operation of the present invention will be described.
First, when the anti-vibration of the bending vibration body or its vicinity is excited by the driving ultrasonic vibrator, the bending vibration is induced in the bending vibration body.

  Vibration is applied while pressing a flange, which is placed on the abdomen of the vibration of the flexural vibrator (this abdomen is an abdomen of vibration at a site different from the abdomen to which the driving ultrasonic transducer is attached) through the resonance support. When applied, ultrasonic machining (bonding) can be realized by in-plane vibration of the processed (bonded) surface while the workpieces (bonding target) at the tip of the vibrating body are pressurized.

  Two of the drive ultrasonic vibrators having the same characteristics are coupled to the vibrating body in a direction perpendicular to each other in a plane perpendicular to the central axis of the bending vibrating body, which is an antinode of the vibration of the bending vibrating body, When both ultrasonic transducers are adjusted so that the vibration phase difference is π / 2, the flexural vibrator becomes a low-loss composite flexural vibrator, and the tips of the vibrators form circular and elliptical vibration trajectories.

  Similarly, two or more drive ultrasonic vibrators having uniform characteristics are asymmetrically or symmetrically provided in the plane that is the antinode of the vibration of the flexural vibrator and is perpendicular to the central axis of the flexural vibrator. By coupling and simultaneously driving with a vibration phase difference corresponding to the installation position, the flexural vibrator becomes a composite flexural vibrator with high output and low loss, and the tip of the vibrator also draws a circular and elliptical vibration trajectory.

Next, embodiments of the support device of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram of a flexural vibrator and a resonance support for explaining the present invention, and vibration modes of each part thereof. FIG. 2 is a diagram showing a flexural vibrator and an integral structure flange and a driving ultrasonic vibrator at a vibration abdomen. FIG. 3 and FIG. 4 are schematic views of the bending vibration body for explaining the ultrasonic processing machine installed with the vibration mode, FIG. 3 and FIG. FIG. 5 is a schematic diagram of a flexural vibrator and a vibration support having a structure that becomes an antinode and a node, and a vibration mode thereof. FIG. 5 shows a flexural vibration in which the resonance support of the present invention has a cylindrical shape and both ends thereof have a structure that becomes an antinode of vibration. FIG. 6 is a schematic diagram of the body and the vibration support tool and its vibration mode. FIG. 6 is a view of the flexural vibration body viewed from the driving ultrasonic vibrator when the flexural vibration body is attached to and detached from the resonance support tool in the example of FIG. It is a locus map of free admittance.

In FIG. 1, dotted lines indicate the stationary state of the columnar flexural vibrator 1 and the columnar (or cylindrical) resonance support 3, and 11, 12, and 13 represent the flexural vibrator 1 when the flexural vibrator 1 is stationary. These are the central axis and the generatrix of the outer peripheral surface (a tangent line between the plane including the central axis 11 and parallel to the central axis 11 and the outer peripheral surface).
In FIG. 1, symbols L and N respectively indicate the antinodes and nodes of the vibration of the flexural vibrator 1, and the subscripts n (1, 2, 3,...) Are nth from the upper end side of the flexural vibrator 1. Shows belly and nodes.
The solid line in FIG. 1 represents the vibration modes of the flexural vibrator 1 and the resonance support 3.

In FIG. 1, when the position of the node N1 on the bus 12 of the flexural vibrator 1 at rest is indicated by reference numeral 14, the point 14 is moved to the position of reference numeral 15 by vibration. Similarly, when the position corresponding to the central axis 11 of the vibration antinode L2 is indicated by reference numeral 16, the point 16 is moved to the position of reference numeral 17 by vibration.
The distance between the nodes 14 and 15 is Z1, the distance between the antinodes 16 and 17 is A, the diameter of the flexural vibrator 1 is D1, and the flexural vibration wavelength is λ1 (double length between L2 and L3). And the distance Z1 is expressed by Equation (1).

In FIG. 1, the node 4 on the outer side surface of the resonance support 3 attached to the flange 2 installed at the site of the belly L2 of the flexural vibrator 1 corresponds to the vibration of the flange 2 with an amplitude A. To the position of 5.
In FIG. 1, reference symbols li and ni denote the i-th antinode and node from the upper end of the resonance support 3, respectively.
Next, the distance between the nodes 4 and 5 is Z2, the bending vibration wavelength of the resonant support 3 is λ2 (twice the length between l1 and l2), and the diameter (thickness in the case of a cylinder) of the resonant support 3 is set. When D2 is set, the distance Z2 is expressed by Expression (2) similarly to Expression (1).

  From Equation 1 and Equation (2), the ratio of the distances Z1 and Z2 is given by Equation (3).

From the equation (3), the distance ratio Z2 / Z1 is a value obtained by dividing the diameter ratio (D2 / D1) of both cylindrical bodies by the wavelength ratio (λ2 / λ1).
On the other hand, the relationship between the wavelength λ (mm) and the diameter D (mm) is approximately expressed by Equation (4) when the material of the flexural vibrator 1 and the resonant support 3 is stainless steel (SUS347) and the resonant frequency is 40 kHz. Can do.

Assuming that the diameters of both cylindrical bodies are D1 = 30 mm and D2 = 6 mm, the distance ratio Z2 / Z1 is 0.34 from Equation (3) and Equation (4).
That is, when compared with the moving distance Z1 in the case of the conventional node fixing device that supports the vibration body at the nodes, the supporting device of the present invention can easily move from the distance Z1 to the moving distance Z2 (described above) from the expressions (3) and (4). In this design example, it is sufficient to fix 0.34Z1), and accordingly, the mounting loss due to the resonant support 3 of the flexural vibrator 1 can be greatly reduced.

  Next, the present invention will be described with reference to FIG. In FIG. 2, reference numeral 21 denotes an ultrasonic vibrator for driving the flexural vibrator 1. The annular electrostrictive element 22 and the annular electrodes 23 and 24 are sandwiched between the back body 25 and the front body 26, and each member is sandwiched. By screwing the central portion (not shown), a bolted Langevin type ultrasonic transducer (hereinafter referred to as BLT) is configured, and by applying a voltage of a required frequency to the electrodes 23 and 24, Excites ultrasonic vibration.

  The BLT 21 has a vibration transmitting horn 27 connected in cascade on the same axis as the BLT 21, and the BLT 21 and the BLT 28 having the same configuration as the BLT 21 are bent at the front end surfaces of the horns to the vibration antinodes of the vibrating body 1. Each axial center is orthogonally connected on a plane and is attached by screw connection (not shown).

  With the above configuration, the longitudinal vibration body of the BLT 21 and the horn 27 in FIG. 2 and the flexural vibration of the flexural vibration body 1 resonate at the same frequency. When an electrical signal having a resonance frequency between the BLT 21 and the flexural vibrator 1 is applied to the electrodes 23 and 24 of the BLT 21, the vibration of the axis of the flexural vibrator 1 becomes the vibration mode 29 shown in FIG.

  The flange 2 of the flexural vibrator 1 is installed at the position of the vibration antinode L2, and the BLT 21 is installed at the position of antinode L3. The length of the flexural vibrator 1 is longer by half the wavelength than in the case of FIG.

  The vibration mode 29 in FIG. 2 shows one-dimensional flexural vibration of the flexural vibrator 1 by the BLT 21. The second antinode position L3 in the flexural vibrator 1 vibration has a second plane angle perpendicular to the BLT 21. A composite flexural vibration is induced in the flexural vibrator 1 by screw coupling (not shown) a horn connected in series with the BLT 28.

The vibration of the tip L5 of the flexural vibrator 1 is applied to the upper workpiece (for example, a bonded semiconductor chip) 18 and the lower workpiece (for example, the substrate) 19 fixed to the cradle 20. The
In this case, the necessary pressing force F is processed from the flexural vibrator 1 by the pressurizing device (not shown) via the flange 2 and the resonant support (see reference numerals 31, 41 and 51 in FIGS. 3 to 5). Added to bodies 18,19. When the workpieces 18 and 19 are a semiconductor chip and a substrate, they are joined by a load perpendicular to the joining surface and ultrasonic elliptical vibration parallel to the joining surface.

In FIG. 3, reference numeral 31 denotes a resonance support tool according to the present invention which is a cylindrical body mounted on the flange 2. As shown in the vibration mode 32, the flange contact surface is the vibration antinode (roller end) and the opposite surface vibrates. Nodal surface 33 (fixed end).
The node surface 33 is attached to the fixed disk 34, and the node surface 33 that abuts the fixed disk 34 forms a fixed end of vibration. The required pressing force to the flexural vibrator 1 is applied via the fixed disk 34.

In FIG. 4, 41 is an example of the resonance support tool of the present invention by a cylindrical body attached to the flange 2, and as shown in its vibration mode 42, the flange contact surface is the vibration abdominal surface (roller end). The opposite surface is a vibration nodal surface 43 (fixed end).
As in the case of FIG. 3, the node surface 43 is mounted on the fixed disk 44, and the node surface 43 in contact with the fixed disk 44 forms a fixed end of vibration. The required pressing force to the flexural vibrator 1 is applied via the fixed disk 44.

In FIG. 5, 51 is another example of the resonance support tool of the present invention by a cylindrical body mounted on the flange 2, and as shown in its vibration mode 52, both ends are anti-vibration surfaces (the flange contact surface is the roller end, The other end is a free end).
The flexural vibrator 1 is held by installing a flange 53 on the node surface of the cylindrical body 51 and fixing the flange. The required pressing force to the flexural vibrator is applied via the flange 53.

FIG. 6 is an actual measurement example showing the effect of the present invention.
In the example of FIG. 3, 61 and 62 show respective free admittance loops when the BLTs 21 and 28 are connected in parallel and the flexural vibrator 1 and the resonance support 31 are detached and attached.
According to FIG. 6, the dynamic admittance at the time of resonance when attached to and detached from the resonant support is
| Ym0 | = 200 mS, | Ym00 | = 213 mS
It becomes.
And the support loss Lm in the resonance support tool 31 is given by Formula (5).

  From Equation (5), the support loss Lm in the case of FIG. 3 was 6.1%. As described above, the support loss according to the present invention is as small as 6.1% in the example of FIG. 3 (40% or less of the conventional support loss). Even if it compares, there is no inferiority and it can be put to practical use.

  As described above, according to the support device of the present invention, an effect of reducing the support loss of the vibrating body to 10% or less can be obtained.

  In addition, according to the support device of the present invention, it is possible to realize the support having a high rigidity of the vibrating body and the high positioning accuracy of the tip, and therefore it is possible to obtain a highly efficient and highly accurate bending vibrator for an ultrasonic machine. .

  Further, in the present invention, the cylindrical resonant support tool is replaced by a circular disc-shaped or center-holed dish-shaped member, which is not shown, but has a constant or variable thickness. can do. Even in a support using such a member, the flexural vibration of the support is converted from flexural vibration + longitudinal vibration to longitudinal vibration. By fixing the vibration node, the flexural vibration is the same as in the illustrated example. It is possible to support the body effectively. In addition, the disk-shaped or dish-shaped or hollow frustoconical support has an effect of further reducing the vibration displacement of the fixed portion by making the peripheral portion thicker than the central portion.

The schematic diagram of the bending vibration body and resonance support tool for explaining the present invention support device, and its vibration mode. The schematic diagram of the bending vibration body for demonstrating the ultrasonic processing machine to which this invention support aspect is applied, and its vibration mode. The schematic diagram of the resonance support tool and bending vibration body which comprised this invention support tool with the cylindrical body, and each vibration mode. The resonance support tool which comprised this invention support tool with the cylindrical body, the bending vibration body, and the schematic diagram of each vibration mode. The schematic diagram of the resonance support tool and bending vibration body which comprised this invention support tool with the cylinder with a flange, and each vibration mode. The figure of the free admittance loop of the flexural vibration body for demonstrating the effect of this invention support tool.

Explanation of symbols

1 Bending vibrator 2 Flange 21, 28 BLT
29 Vibration modes of the flexural vibrator 1 3, 31, 41, 51 Resonant support tools 32, 42, 52 Vibration modes of the resonance support tools 31, 41, 51
34, 44, Fixed disk 53 Flange for fixing the resonant support 51 61, 62 Free admittance loop of the flexural vibrator when the resonant support is detached and attached

Claims (4)

A support device for an ultrasonic flexural vibrator that holds a flange installed at the vibration abdomen of the ultrasonic flexural vibrator with a support that flexes and vibrates at the same resonance frequency as the ultrasonic flexural vibrator,
The support is a flange abutment surface of the support and the abdomen of the vibration of the support, characterized in that a fixed end to a node portion of the vibration of the support, the support device of the ultrasonic flexural vibrator.   The support device for an ultrasonic flexural vibrator according to claim 1, wherein the support has a columnar or cylindrical structure, and a surface opposite to a flange contact surface is the fixed end.   The support device has a cylindrical structure, a surface opposite to the flange contact surface is a vibration belly portion, and a fixing flange of the support device is installed as the fixed end at a vibration node of the cylindrical structure support device. Item 2. The support device for an ultrasonic flexural vibrator according to Item 1.   The support device for an ultrasonic flexural vibrator according to claim 1, wherein the support is formed of a hollow frustoconical or annular disk-shaped member and fixes a vibration node.

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