U.S. patent application number 09/822924 was filed with the patent office on 2001-10-11 for ultrasonic horn for a bonding apparatus.
This patent application is currently assigned to KABUSHIKI KAISHA SHINKAWA. Invention is credited to Kyomasu, Ryuichi, Nishiura, Shinichi.
Application Number | 20010027987 09/822924 |
Document ID | / |
Family ID | 18618434 |
Filed Date | 2001-10-11 |
United States Patent
Application |
20010027987 |
Kind Code |
A1 |
Kyomasu, Ryuichi ; et
al. |
October 11, 2001 |
Ultrasonic horn for a bonding apparatus
Abstract
An ultrasonic horn used in, for instance, a bonding apparatus,
being provided with a capillary attachment hole formed so as to be
smaller than the capillary and a jig insertion hole that
communicates with the capillary attachment hole. Byway of inserting
a jig into the jig insertion hole, the jig insertion hole is pushed
open that causes the capillary attachment hole to be widened, so
that the capillary is inserted and received in this enlarged
capillary attachment hole. The capillary is fastened in place by
the elastic force that is generated when the capillary attachment
hole returns to its original shape, and the capillary is held in
the horn main body without using any fastening tools.
Inventors: |
Kyomasu, Ryuichi; (Kodaira,
JP) ; Nishiura, Shinichi; (Fussa, JP) |
Correspondence
Address: |
KODA & ANDROLIA
Suite 3850
2029 Century Park East
Los Angeles
CA
90067-3024
US
|
Assignee: |
KABUSHIKI KAISHA SHINKAWA
|
Family ID: |
18618434 |
Appl. No.: |
09/822924 |
Filed: |
March 30, 2001 |
Current U.S.
Class: |
228/1.1 ;
228/110.1; 228/180.5; 228/4.5 |
Current CPC
Class: |
B23K 20/106 20130101;
H01L 2924/01033 20130101; H01L 2924/01004 20130101; H01L 2924/01005
20130101; H01L 24/78 20130101; H01L 2224/78301 20130101; B23K
20/005 20130101; H01L 2924/01006 20130101; H01L 2924/00014
20130101; H01L 2924/00014 20130101; H01L 2224/48 20130101; H01L
2924/00014 20130101; H01L 2224/45099 20130101 |
Class at
Publication: |
228/1.1 ;
228/4.5; 228/110.1; 228/180.5 |
International
Class: |
B23K 001/06; B23K
005/20; B23K 020/10 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 6, 2000 |
JP |
2000-104980 |
Claims
1. An ultrasonic horn for a bonding apparatus for holding a
capillary at one end of a horn main body of said ultrasonic horn,
wherein said horn main body is provided with: a capillary
attachment hole formed in said one end of said horn main body, said
capillary attachment hole being smaller in diameter than said
capillary, and a jig insertion hole formed in said horn main body
so as to communicate with said capillary attachment hole, and
wherein said jig insertion hole is pushed open using a jig, thus
widening said capillary attachment hole so as to be larger than
said capillary so that said capillary is inserted into said
capillary attachment hole, and said capillary is fastened in place
in said capillary attachment hole by elastic force that is
generated when said capillary attachment hole returns to its
original shape.
2. The ultrasonic horn for a bonding apparatus according to claim
1, wherein said horn main body is symmetric with respect to an
axial center of said horn main body.
3. The ultrasonic horn for a bonding apparatus according to claim
1, wherein said jig insertion hole communicates with said capillary
attachment hole with a slit in between.
4. The ultrasonic horn for a bonding apparatus according to claim
1, wherein an area surrounding said capillary attachment hole and
jig insertion hole is formed as a closed structure.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an ultrasonic horn used in
a bonding apparatus and more particularly to an ultrasonic horn
that transmits ultrasonic vibrations to a capillary with a bonding
wire passing therethrough.
[0003] 2. Prior Art
[0004] In ultrasonic horns used in, for instance, a wire bonding
apparatus, a capillary is fastened in a capillary attachment hole
that is formed in the tip end portion of the horn main body.
Conventional capillary fastening structures can be categorized into
two types.
[0005] In the first type, a slit is formed vertically along the
axial center of the horn main body in a portion of the capillary
attachment hole, and the capillary is fastened in place by
tightening the area surrounding this slit with a bolt. This type of
fastening structure is disclosed in, for instance, Japanese Patent
Application Laid-Open (Kokai) Nos. H6-163648, H6-283578 and
H11-121546. In particular, in Japanese Patent Application Laid-Open
(Kokai) No. H6-163648, the ultrasonic horn is formed with a slit,
and it is further provided with a stress compensation hole that is
larger than the capillary mounting hole. In Japanese Patent
Application Laid-Open (Kokai) No H6-283578, a trench is formed in
the ultrasonic horn so that it works in a bifurcated fashion. In
Japanese Patent Application Laid-Open (Kokai) No H11-121546, a
capillary-holding hole is formed at one end of the ultrasonic horn,
and a vertical slit is provided from this hole in the opposite side
t the tip end of the horn.
[0006] In the second type, a slit is formed so as to extend through
the capillary attachment hole from the tip end of the horn main
body, the area of the capillary attachment hole is endowed with an
elastic force, and a screw hole is formed on one side of the slit.
A bolt is screwed into the screw hole and tightened. When the bolt
is thus tightened, the other side of the slit is pressed so that
the slit and capillary attachment hole are widened. After the
capillary is inserted into the capillary attachment hole, the bolt
is loosened and removed from the horn main body. As a result, the
capillary is fastened in place only by the elastic force of the
horn main body. This fastening structure is described in Japanese
Utility Model Application Laid-Open (Kokai) No. H5-59840.
[0007] However, the above capillary fastening structures have
problems.
[0008] The first type fastening structure has the following
problems:
[0009] (1) Since the structure involves a bolt that is used to
fasten the capillary to the horn main body, the masses on the left
and right sides of the horn main body with respect to the axial
center of the horn main body are different. As a result, the
ultrasonic vibration at the tip end portion is disturbed, and the
accurate transmission of ultrasonic waves to the capillary is
hindered.
[0010] (2) The bolt and the screw hole in the horn main body wear
with time. As a result, changes in the configuration of the
ultrasonic vibration occur, causing the capillary tightening force
to be unstable.
[0011] (3) The tightening torque of the bolt must be sufficiently
strong so that the bolt itself does not show any relative movement
or slippage with respect to the horn main body. Such a relative
movement or slippage is derived, for instance, from the bolt
becoming loose during the bonding operation and from wear in the
bolt. The limit of the tightening torque of the bolt is determined
by the size and strength of the head of the bolt that is used for
tightening. Currently, the diameter of the head of the bolt
generally used in such cases is approximately 3 mm, and this bolt
head can withstand a torque of approximately 2 kg. However, in
ultrasonic vibration at 80 kHz, the weight of the bolt itself is
too heavy. Thus, with the tightening torque of approximately 2 kg,
the tightening force is overcome by the force arising from the
acceleration of the ultrasonic vibration, thus causing the bolt to
slip on the horn main body, and further causing wear of the bolt,
energy loss and unstable vibration. Furthermore, with the
tightening torque of approximately 2 kg, the shock generated by
gravitational acceleration during movement of the capillary cannot
be suppressed when ultrasonic oscillation is at 100 kHz, thus
causing unstable vibrations in the capillary.
[0012] (4) The bolt is generally tightened using a torque driver in
order to ensure a constant tightening force. However, torque
drivers are expensive, and also they have drawbacks of showing
changes in tightening torque unless periodically adjusted. As a
result, troubles such as faulty tightening, etc. can occur
easily.
[0013] The second type fastening structure has the following
problems:
[0014] (1) Since a screw hole is formed on one side of the slit,
the masses on the left and right sides of the horn main body with
respect to the axial center of the horn main body are different as
in the above first type. Thus, the ultrasonic vibration at the tip
end portion is disturbed, hindering the accurate transmission of
ultrasonic waves to the capillary.
[0015] (2) In order to ensure a sufficient grip in the tip end
portion of the horn main body that is open, it is necessary to
increase the thickness of the tip end portion so as to increase the
elastic force of the horn main body. However, in the structure for
gripping the capillary from the left and right sides, the capillary
may be damaged before a sufficient gripping force is applied to the
capillary.
[0016] (3) Furthermore, so as to transmit ultrasonic vibration
efficiently from the vibrator provided in the rear portion of the
horn main body, it is generally necessary to design the tip end
portion of the horn main body slender. There are restrictions also
on the diameter and length dimensions of the horn main body in view
of performance. Currently, the thickness of the capillary gripping
portion located in the tip end portion of an ordinary horn main
body is approximately 1 mm. The elastic force obtained from such a
thickness is easily overcome by the shock generated by
gravitational acceleration during movement of the capillary in
ultrasonic oscillation at 60 kHz or greater; and as a result, the
capillary is not retained.
[0017] (4) Since the tip end portion of the horn main body is
opened by a slit, such a tip end portion is caused to undergo
repeated slight expansions and contractions by the ultrasonic
vibration. As a result, tensile and compressive stresses are
generated inside the capillary, causing cracks, failing to generate
a sufficient holding force. Furthermore, destructive accidents can
occur as a result of changes in strength, etc. even in ordinary
use.
BRIEF SUMMARY OF THE INVENTION
[0018] Accordingly, the object of the present invention is to
provide an ultrasonic horn for a bonding apparatus that suppresses
the generation of unnecessary vibrations other than the ultrasonic
vibration at the fundamental frequency, improves the bondability,
and realizes stable gripping for the capillary by a simple
structure.
[0019] The above-object is accomplished by a unique structure for
an ultrasonic horn used in a bonding apparatus in which a capillary
is fastened in a capillary attachment hole formed in the tip end
portion of the horn main body, and in the present invention:
[0020] the capillary attachment hole is formed smaller than the
capillary in diameter,
[0021] a jig insertion hole is formed in the horn main body so as
to communicate with the capillary attachment hole, and
[0022] the area surrounding the capillary attachment hole and jig
insertion hole is formed as a closed structure, and wherein
[0023] the jig insertion hole is pushed open using a jig, thus
widening the capillary attachment hole so that the capillary
attachment hole becomes larger than the capillary and the capillary
is inserted into the capillary attachment hole, and
[0024] the capillary is fastened in place by the elastic force
generated when the capillary attachment hole returns to its
original shape, without requiring any component other than the horn
main body for holding the capillary.
[0025] In the above structure, the horn main body is formed so that
it is symmetrical with respect to its own axial center.
[0026] Furthermore, the jig insertion hole communicates with the
capillary attachment hole either directly or via a slit.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0027] FIG. 1A is a top view of the ultrasonic horn for a bonding
apparatus according to one embodiment of the present invention,
FIG. 1B being a front view thereof;
[0028] FIGS. 2A, 2B, 2C and 2D illustrate the steps of fastening
the capillary in the capillary attachment hole;
[0029] FIG. 3A is a front view of the jig used in the present
invention, FIG. 3B being a bottom view thereof; and
[0030] FIG. 4A through 4F show top views of the horn main bodies
according to various embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0031] Embodiments of the present invention will be described with
reference to the accompanying drawings.
[0032] FIGS. 1A and 1B show a capillary 20 and a horn main body 10
in which the capillary 20 is installed. As seen form FIGS. 1A and
1B, the horn main body 10 is formed with a capillary attachment
hole 11 and an elliptical or oval jig insertion hole 12. The
capillary attachment hole 11 receives the capillary 20 and fastens
the capillary 20 in place. As best seen from FIG. 1B, the capillary
attachment hole 11 is formed vertically in the tip end portion of
the horn main body 10. The elliptical jig insertion hole 12 is
formed in the horn main body 10 so as to be located on the opposite
side of the capillary attachment hole 11 from the tip end portion
of the horn main body 10. The jig insertion hole 12 communicates
with the capillary attachment hole 11 via a vertical slit 13 formed
in between. Furthermore, a slit 14 is formed vertically in a part
of the jig insertion hole 12 located on the opposite side of the
attachment hole 11 from the slit 13.
[0033] Thus, the capillary attachment hole 11, slit 13, jig
insertion hole 12 and slit 14 are formed continuously in a closed
structure by the edges of these elements. Furthermore, the horn
main body 10 is formed so as to be symmetrical with respect to its
own center axis that extends in the direction of length
thereof.
[0034] As seen from FIGS. 1A, 1B and 2D, when the capillary 20 is
fastened to the horn main body 10, the capillary 20 is gripped by
the elastic force of the horn main body 10 in the area surrounding
the capillary attachment hole 11. For this reason, as seen from
FIG. 2A, the capillary attachment hole 11 (or its inner diameter)
is slightly smaller (by approximately 200 .mu.m) than the external
diameter of the capillary 20.
[0035] FIGS. 3A and 3B show a jig 30 that is to be inserted into
the jig insertion hole 12 so as to push the jig insertion hole 12
open or wider. The jig 30 comprises an operating lever 31 and an
insertion hole pressing portion 32 that is disposed on the
undersurface of one end of the operating lever 31. The insertion
hole pressing portion 32 has an elliptical shape in its horizontal
cross-section as best seen from FIG. 3B. The pressing portion 32 is
slightly smaller than the jig insertion hole 12.
[0036] The manner of fastening the capillary 20 to the horn main
body 10 will be described below with reference to FIGS. 2A through
2D.
[0037] As shown in FIG. 2A, the insertion hole pressing portion 32
of the jig 30 is first inserted in the jig insertion hole 12 of the
horn main body 10. Then, the operating lever 31 of the jig 30 is
turned 90 degrees. When the operating lever 31 is thus turned 90
degrees, the jig insertion hole 12 and slit 13 are pushed away so
as to be wider by the insertion hole pressing portion 32 as shown
in FIG. 2B. As a result, the capillary attachment hole 11 is
widened, and it becomes larger in diameter than the diameter of the
capillary 20.
[0038] Then, the capillary 20 is inserted into the capillary
attachment hole 11, and the operating lever 31 of the jig 30 is
turned 90 degrees further (or back) so that the insertion hole
pressing portion 32 is returned to its original position. Thus, as
a result of the elastic force that causes the jig insertion hole
12, slit 13 and capillary attachment hole 11 to return to their
original states shown in FIG. 2A, the capillary 20 in gripped by
the capillary attachment hole 11 as shown in FIG. 2C. Then, the
insertion hole pressing portion 32 of the jig 30 is removed from
the jig insertion hole 12, thus completing the fastening of the
capillary 20 to the horn main body 10. When the capillary 20 is to
be removed from the horn main body 10, an operation that is the
reverse of the steps described above is performed.
[0039] In the above embodiment, a bolt such as that used in the
above-described first type fastening structure is not used. Also, a
screw hole such as that used in the second type fastening structure
is not formed. As a result, the masses on the left and right of the
horn main body 10 with respect to the axial center of the horn main
body 10 are the same, and the disturbance of the vibration is
eliminated. Furthermore no unnecessary vibration is generated, and
the loss of energy is eliminated. In addition, naturally no bolt or
screw hole wear occurs, and the horn main body 10 is not worn out,
so that changes in the shape of the horn main body 10 that would be
caused over time by repeated replacement of the capillary 20 is
eliminated. Thus, a stable use of the capillary can be assured over
a long period of time. Furthermore, since there is no need for a
screw hole, and no need for fastening bolts, the horn main body 10
can be manufactured inexpensively.
[0040] In addition, there is no need to use an expensive torque
driver, etc. in order to ensure that the torque is constant when
the screw is tightened as in the first type fastening structure.
Thus, a constant gripping force is obtained by the jig 30 that is
of a simple structure when a new capillary 20 is fastened in the
horn main body 10.
[0041] The test for the structure of the above embodiment indicates
that the horn main body 10 holds the capillary 20 with a gripping
force that is more than three times the gripping force obtained by
the first type fastening structure of the prior art. For example,
when the bolt of the first type fastening structure is tightened
with a torque of 1.5 kg, then the gripping force of the capillary
attachment hole is approximately 50 N. However, the gripping force
of the capillary attachment hole 11 of the horn main body 10 of the
shown embodiment is greater than 150 N.
[0042] In regard to shocks generated from the gravitational
acceleration that occurs during the movement of the capillary 20,
in the case of an oscillation amplitude of 4 .mu.m, for instance,
the shock from gravitational acceleration at 150 kHz is 90 N, and
the shock generated from gravitational acceleration at 180 kHz is
130 N. In the shown embodiment of the present invention, the
capillary 20 is held by a sufficient gripping force of 150 N or
more even in the case of an ultrasonic vibration of 100 kHz or
greater, in which the shock is extremely large. Accordingly, the
ultrasonic waves can be accurately transmitted to the object of
vibration.
[0043] Furthermore, in the above embodiment, the capillary 20 is
gripped by the capillary attachment hole 11 in which the tip end of
the horn main body 10 is closed and not open as best seen from FIG.
1A. Accordingly, a gap in the capillary attachment hole 11 is
prevented; and even in the case that capillaries of different
diameters are to be fastened, three or more contact points are
guaranteed between the capillary and the capillary attachment hole
11. Thus, stable fastening of the capillary is constantly assured.
Furthermore, the capillary 20 can be fastened in place by a simple
and easy mounting method without using any precision tools, etc.;
and a stable gripping force is applied thereto. Moreover, even if
the gripping force on the capillary 20 is increased, only a
compressive stress acts on the capillary 20, with no generation of
any tensile stress. Thus, the capillary 20 is free from any
damage.
[0044] Various other embodiments of the present invention will be
described with reference to FIGS. 4A through 4F. Parts that are the
same as or correspond to those in the above embodiment will be
assigned the same reference numerals in the description below.
[0045] FIGS. 4A and 4B respectively illustrate second and third
embodiments of the present invention. Though in the embodiment of
FIGS. 1A and 1B the jig insertion hole 12 communicates with the
capillary attachment hole 11 via the slit 13, in the embodiments of
FIGS. 4A and 4B the jig insertion hole 12 are formed so as to
communicate directly with the capillary attachment hole 11, and not
slits are formed in between. In the embodiment of FIG. 4B, the jig
insertion hole 12 is formed so as to extend to the area of the slit
14 shown in FIGS. 1A and 4A. In other words, there is no slit 14
formed in the horn main body 10 of the embodiment of FIG. 4B.
[0046] In the fourth embodiment of the present invention shown in
FIG. 4C, the jig insertion hole 12 is formed in a rectangular
shape. Thus, the jig insertion hole 12 may have any shape that can
be pushed open so as to become larger by the jig 30, and there are
no particular restrictions on the shape.
[0047] FIG. 4D illustrates the fifth embodiment of the present
invention. In this embodiment, there is a certain degree of
thickness between the capillary attachment hole 11 and the tip end
of the horn main body 10; and a slit 15 is formed in the thick end
portion so as to extend toward the tip end of the horn main body 10
from the capillary attachment hole 11. This embodiment is a
modification of the fourth embodiment shown in FIG. 4C. It goes,
however, without saying that such a slit 15 can be formed in the
embodiments shown in FIG. 1, FIG. 4A and FIG. 4B in cases the horn
main body 10 has a certain thickness between its tip end and the
capillary attachment hole 11.
[0048] FIGS. 4E and 4F illustrate, respectively, the sixth and
seventh embodiments of the present invention. In these embodiments,
the portion of the horn main body 10 that is between the capillary
attachment hole 11 and the tip end of the horn main body 10 is
relatively long, and the jig insertion hole 12 is formed between
the capillary attachment hole 11 and the tip end of the horn main
body 10. In the embodiment of FIG. 4E, the jig insertion hole 12 is
formed so as to communicate with the capillary attachment hole 11
via a slit 13; and in the embodiment of FIG. 4F, the jig insertion
hole 12 is formed so as to communicate directly with the capillary
attachment hole 11 with no slit 13 in between.
[0049] In all of the embodiments shown in FIGS. 4A through 4F, the
capillary (not shown) is securely gripped elastically by the
capillary attachment hole 11 in the same manner as shown in FIGS.
2A through 2D by way of inserting the jig 30 shown in FIGS. 3A and
3B into the jig insertion hole 12 and then by turning it.
[0050] The jig 30 may be any tool as long as it is capable of
pushing the jig insertion hole 12 open after inserted in the jig
insertion hole 12. Thus, the jig 30 is not limited to the shape
shown in FIGS. 3A and 3B.
[0051] As seen from the above, in the present invention, the
capillary attachment hole smaller in diameter than the capillary is
formed in the horn main body, the jig insertion hole that
communicates with this capillary attachment hole is formed next to
the capillary attachment hole, and the area surrounding the
capillary attachment hole and jig insertion hole is formed as a
closed structure; and the jig insertion hole is pushed open by a
jig, thus widening the capillary attachment hole so that the
capillary attachment hole becomes larger in diameter than the
capillary, after which the capillary is inserted into the capillary
attachment hole, and then the jig is removed from the jig insertion
hole so that the capillary is held in place by the elastic force
that is generated when the capillary attachment hole returns to its
original shape. Thus, no component other than the horn main body is
used for fastening the capillary to the horn main body. Also, the
generation of unnecessary vibrations other than the ultrasonic
vibration at the fundamental frequency is suppressed, the
bondability in bonding improves, and stable capillary gripping is
realized by means of a simple structure. Further, an inexpensive
ultrasonic horn for use in a bonding apparatus can be obtained.
* * * * *