close

Вход

Забыли?

вход по аккаунту

?

DESCRIPTION JPH07153801

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPH07153801
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
bonding apparatus for semiconductors, such as a thermobonding wire bonding apparatus with
nail head ultrasonic wave, an ultrasonic wedge wire bonding apparatus, a single TAB bonding
apparatus, and more particularly, a bonding tool attached to one end. And a vibration generating
source such as an electrostrictive element or a magnetostrictive element.
[0002]
2. Description of the Related Art For example, a conventional nail head thermocompression
bonding wire bonding apparatus has a structure as shown in FIG. That is, a support shaft 2 is
fixed to the bond arm 1 and the support shaft 2 is rotatably supported by a bonding head (not
shown) directly or via a lifter arm. The horn support 4 of the ultrasonic horn 3 is fixed to the
bond arm 1. The ultrasonic horn 3 is composed of a horn main body 6 to which a bonding tool 5
through which a wire (not shown) is inserted is attached at one end, and a vibrator 7 screwed to
the horn main body 6.
[0003]
The vibrator 7 has a structure in which a vibration generating source 8 is attached by a screw
method called a Langevin type, and a horn attachment member 9 attached to the horn main body
6 and a screw part formed on both ends are screwed to the horn attachment member 9 The
vibration source mounting shaft 10 to be coupled, the insulating pipe 11 fitted to the vibration
13-04-2019
1
source mounting shaft 10, and a plurality of Donut-shaped electrostrictive elements or
magnetostrictive elements inserted in the insulating pipe 11 and laminated in a plurality It
comprises a source 8 and a nut 12 screwed to the vibration source mounting shaft 10 to clamp
the vibration source 8.
[0004]
Accordingly, the conventional ultrasonic horn 3 is mounted on the opposite side of the bonding
tool 5 side when the vibration source 8 is viewed from the horn support 4.
The vibrator 7 has horn attachment members 9 and nuts 12 attached to both sides of the
vibration source 8 and adjusted to a desired frequency, and the acoustic length of the vibrator 7
is 1⁄2 wavelength. Although it must be an integral multiple, in this structure, one having a half
wavelength is used because it does not have to be extended. At the same time as the free end 13
of the vibrator 7 becomes an antinode (amplitude is large) of the vibration, the horn attachment
portion 14 of the horn attachment member 9 also becomes an antinode and mounting is easy.
[0005]
Next, the operation will be described. The vibration of the vibration source 8 is transmitted to the
entire ultrasonic horn 3 to make a vibration of a standing wave in the ultrasonic horn 3 to supply
necessary energy to the bonding tool 5. In the unloaded state (unbonded state), the energy is
stored in a stable state, and in the finely made ultrasonic horn 3, the horn support 4 is sized so
that a node can be formed. Even when the ultrasonic horn 3 is attached to the bond arm 1, the
movement of the horn support 4 is small and the loss is small. In this unloaded condition, the
ultrasonic horn 3 operates like a tuning fork, and the horn support 4 receives vibrations from the
left and right symmetrically and does not move left and right. The vibration source 8 is usually
driven such that the amplitude becomes a prescribed value by constant current drive or the like,
and when energy is used for bonding through the bonding tool 5, the vibration source 8 side and
the bonding tool 5 side are The energy balance is broken, the vibration nodes move, and the
energy necessary for the balance is sent. Bonding using ultrasonic waves is performed in this
manner.
[0006]
13-04-2019
2
The conventional ultrasonic horn 3 is substantially axisymmetric with respect to the horn axis,
and a bonding tool 5 is attached asymmetrically to the axis at its tip. For this reason, the
ultrasonic horn 3 tries to inject energy into the bond surface by moving the bonding tool 5
horizontally by performing only the movement of expansion and contraction in the axial
direction, but the resistance between the bonding tool 5 and the bond surface Thus, the
operation of the actual bonding tool 5 tip is not controlled including components other than
horizontal. That is, bonding is performed depending on the load and the bonding tool 5.
[0007]
By the way, recently, as the density of semiconductor devices is increased, various elements for
enabling high density wiring have been frequently added to pad materials. Along with this, the
shape of the pad surface and the structure of the oxide film have become diverse, and it has
become difficult to maintain the bonding quality. The cause of the bond failure is thought to be
mainly due to the difficulty of diffusion of the material of the pad and the material of the wire
and the difficulty of destruction of the oxide film, but the method of solving it is regardless of the
condition of the pad surface. It is necessary to give sufficient ultrasonic energy. In the ultrasonic
horn 3 having a symmetrical structure with respect to the axial center as in the prior art through
experiments, the inventors of the present invention can not inject stable ultrasonic energy into
the bond plane regardless of the state of the bond plane. discovered.
[0008]
When the cause was investigated, the following was found. The surface of the pad has various
shapes due to crystals of the doped material and their oxides, and sometimes a structure that
makes it difficult for the ball (the ball formed at the tip of the wire inserted into the bonding tool
5) to slip It sometimes becomes. However, since the conventional ultrasonic horn 3 emphasizes
only the axial direction of the ultrasonic horn 3, ie, the scrubbing direction, as described above,
the force (energy) in the axial direction is applied to the bonding tool 5 The friction motion of the
ball at the tip of the bonding tool 5 is difficult to be stably performed only by the application, and
a stable bonding energy can not be provided, and a bond failure occurs.
[0009]
An object of the present invention is to provide a bonding apparatus provided with an ultrasonic
horn capable of giving stable bonding energy to a bonding surface, enabling uniform formation
13-04-2019
3
of an alloy necessary for bonding, and improving bonding quality. It is in.
[0010]
In order to achieve the above object, according to the present invention, there is provided an
ultrasonic horn comprising a bonding tool attached to one end and a vibration source such as an
electrostrictive element or a magnetostrictive element. In the bonding apparatus in which the
ultrasonic horn is attached to the bond arm, the ultrasonic horn is characterized by including a
vertical vibration adjusting portion for adjusting a vertical component of the vibration.
[0011]
In the vibration direction of the ultrasonic horn by the ultrasonic wave generation source, the
vertical direction vibration adjustment section adjusts the vertical component in addition to the
axial direction to stabilize the movement of the bonding tool tip.
That is, the vibration in the oblique direction is controlled by the adjustment of the vibration
component in the axial direction and the vibration component in the vertical direction, and the
application of bonding energy between the bond surface and the ball is stably performed.
[0012]
A first embodiment of the present invention will be described below with reference to FIG.
In addition, the same code | symbol is attached | subjected to the same or equivalent member as
FIG. 5, and the detailed description is abbreviate | omitted. In this embodiment, a weight 20 is
attached to the tip of the ultrasonic horn 3, that is, to the tip of the horn main body 6. As
described above, when the weight 20 is attached to the tip of the horn main body 6, since the tip
of the horn main body 6 is an antinode portion of vibration, the upper and lower balance of the
axial center of the ultrasonic horn 3 is adjusted. In the vibration direction by the ultrasonic wave
generation source 8 of 3, the component of the vertical direction by the weight 20 is generated
in addition to the axial center direction. That is, the tip of the bonding tool 5 becomes a stable
vibration due to the vibration component in the axial direction, the vertical direction by the
weight 20, and the vertical vibration component originally existing by the bonding tool 5, and the
bond surface becomes like a sword mountain. Even in this case, the application of bonding
13-04-2019
4
energy is stably performed regardless of the frictional resistance between the bonding surface
and the ball.
[0013]
As a result of the experiment, in the conventional ultrasonic horn 3, when the ball at the end of
the wire is crimped to the bonding surface, it is crimped in a round shape, making it difficult to
form an alloy near the central part. According to this example, the alloy could be made uniform
over the entire surface, while it was easy to In the case of a ball having a small junction area
required for a high density semiconductor device, a semiconductor device or the like in which a
crack is easily generated, it is important to disperse the joining force over the entire surface of
the ball, and the effect is large.
[0014]
FIG. 2 shows a second embodiment of the present invention. In the present embodiment, a weight
20 is attached to the rear end of the ultrasonic horn 3, that is, the nut 12 of the vibrator 7. The
rear end portion of the ultrasonic horn 3 is an antinode portion of vibration, so even if the weight
20 is attached to the rear end portion, the same effect as that of the above embodiment can be
obtained.
[0015]
By the way, since the ultrasonic horn 3 produces a plurality of antinodes and nodes of vibration,
the weight 20 does not have to be the front end portion or the rear end portion of the ultrasonic
horn 3 as shown in FIGS. You may provide in the belly or node part in the middle of 3. Moreover,
it may replace with the processus | protrusion of the weight 20 and may form a hollow. The
projections or depressions may be provided not on the upper surface of the ultrasonic horn 3 but
on the lower surface. Alternatively, metals having different specific gravities may be provided on
the upper and lower surfaces. That is, by forming the upper and lower portions of the antinode
or node portion of the vibration in an asymmetrical shape, it is possible to form the vertical
vibration adjusting portion for adjusting the vertical component of the vibration.
[0016]
13-04-2019
5
FIG. 3 shows a third embodiment of the present invention. In this embodiment, an asymmetric
shape is provided on the horn support portion 4, and the horn support portion 4 is eccentrically
4 a with respect to the axial center 3 a of the ultrasonic horn 3 by an eccentricity e. That is, since
the vibration transmitting parts 4b of the horn supporting part 4 have different lengths at the
upper and lower sides of the axial center 3a, the energy transmission to the horn main body 6 at
the upper and lower vibration transmitting parts 4b of the axial center 3a is different. In addition
to the heart direction, vertical components are generated. Therefore, even if it is configured as in
this embodiment, the same effect as that of each embodiment can be obtained.
[0017]
FIG. 4 shows a fourth embodiment of the present invention, and shows another embodiment of
the method of forming the vertical vibration adjusting portion. The shaft center 7 a of the
vibrator 7 is vertically offset from the shaft center 6 a of the horn main body 6. In the case of the
present embodiment, the vibration of the shaft center 7a of the vibrator 7 is transmitted to the
horn body 6 as the vibration in the oblique direction, and the vibration in the vertical direction is
controlled. Therefore, even if it is configured as in this embodiment, the same effect as that of
each embodiment can be obtained.
[0018]
According to the present invention, since the ultrasonic horn has the vertical vibration adjusting
portion for generating the vertical component of the vibration, stable bonding energy can be
given to the bonding surface, It enables uniform formation of the alloy necessary for joining, and
can improve bonding quality.
13-04-2019
6
Документ
Категория
Без категории
Просмотров
0
Размер файла
15 Кб
Теги
jph07153801, description
1/--страниц
Пожаловаться на содержимое документа