Metal fusion bonding – Means to apply vibratory solid-state bonding energy to work
Reexamination Certificate
2001-02-01
2002-05-07
Elve, M. Alexandra (Department: 1725)
Metal fusion bonding
Means to apply vibratory solid-state bonding energy to work
C228S049100
Reexamination Certificate
active
06382495
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a chip junction nozzle by which, when semiconductor circuit elements, or the like, are produced, a chip of the semiconductor, SAW element, and the similar element, is taken out of a supply apparatus and is jointed onto a printed circuit board by high frequency bonding, or the like.
Conventionally, when semiconductor circuit elements, or the like, are produced, a structural means and a method by which a chip is taken out of the supply apparatus and is jointed onto the printed circuit board, will be described below. Incidentally, the chip of the object is one used as face down mounting by a flip chip method.
A chip of the semiconductors, SAW elements, and the like, prepared in the supply apparatus is individually taken out, and the chip is moved to a temporary placement base by a moving nozzle provided with a means which can move the chip in the X, Y, Z directions. In this case, when the chip prepared in the supply apparatus is a face-up one, the chip is flipped such that the chip assumes a face down posture between the moving means and the movement process, and when the chip is a face down one, only the movement is conducted.
The chip
1
is moved to the temporary placement board
10
as shown in FIG.
20
(A). Then, the position of the chip
1
is corrected as shown in FIG.
20
(B) by four centering claws
11
, in which respective one of the front and rear, and left and right, settled on the temporary placement base, is moved. Then, as shown in FIG.
20
(C), the chip
1
on the temporary placement base
10
is picked up as shown in FIG.
20
(D) by using a chip junction nozzle
20
which is fixed on a vibration apparatus which is provided with moving means in the X, Y, Z directions, other than the moving nozzle, and which generates ultrasonic, moved, and is positioned on the upper portion of a target position of a printed circuit board
30
to be jointed as shown in FIG.
20
(E). From this situation, the chip junction nozzle
20
is lowered as shown in FIG.
20
(F) to a position in which a bump (conductor metals)
2
formed on the surface of the chip
1
placed on the lower leading edge of the junction nozzle
20
, comes into contact with a conductor pattern (conductor metals)
31
on the printed circuit board
30
, and applies a pressure onto the chip
1
as shown in FIG.
20
(G), and junction is conducted by generating the ultrasonic on the leading edge of the chip junction nozzle
20
. For example, as a typical junction method, there is a GGI (Gold to Gold Interconnection), or the like. Further, as a junction method for another face down mounting, there are a method by heating, a method by heating and pressure, a method in which a special junction medium is inserted between the chip and the printed circuit board, or similar method.
The apparatus to joint by using ultrasonic vibration as described above is also proposed in Japanese Patent Publication 59-208844. However, the recessed portion of the nozzle is considered as conical.
Incidentally, as shown in
FIG. 20
, conventionally, in a general chip junction nozzle
20
, its lower end surface
21
to pick up the chip
1
is a simple flat surface, and a vacuum suction hole
22
is formed in the nozzle center. In the chip junction using such the chip junction nozzle
20
, it is difficult that parallelism of the surface of the chip
1
to be jointed, or that of the height of bump
2
formed on the surface of the chip, to the surface of the pattern
31
of the printed circuit board
30
to be jointed, is vary accurately obtained. Particularly, due to recent increase of the number of bumps of the chip, and an increase of fineness, because the degree of margin of the deformation of the bump itself accompanied by the junction becomes small, a small deviation in the parallelism between a peak of the bump
2
and the printed circuit board
30
becomes also a problem. For example, as shown in
FIG. 21
, when the chip
1
is pressed by using the junction nozzle
20
in the situation that the inclination is several &mgr;m (inclination=h1−h2), chipping or crack of the chip
1
is generated by uniformity of the weighted stress at the junction, or further, in the junction by the generation of the ultrasonic just after, the strength necessary for the junction is not obtained due to unevenness of the strength of the jointed portion, or so. Particularly, the junction failure due to the inclination of the chip
1
and the printed circuit board
30
is frequently happened when these are parallel to the direction of vibration to generate the ultrasonic (the case shown in FIG.
21
).
The conventional chip junction nozzle
20
is operated such that the chip
1
to be jointed is sucked by negative pressure, and the chip is closely adhered to the lower end surface
21
of the chip junction nozzle. Accordingly, heats conducted from the substrate during chip junction or heats generated by the ultrasonic vibration can not be radiated and the temperature of the chip rises, and there is a possibility that nonconformity occurs in the chip.
SUMMARY OF THE INVENTION
In view of the above described points, the object of the present invention is to provide a chip junction nozzle by which the junction can be always conducted in the situation of parallel to the pattern of the printed circuit board to be jointed, and the chip can be mounted with uniform and strong junction strength.
In order to attain the above object, the chip junction nozzle of the present invention comprises: opposite slopes contacting in parallel to edges of two sides of the chip centering around the nozzle center; and a vacuum suction hole opened at the nozzle center, and in that the slope is formed into a mirror surface.
According to such the structure, in the process in which the chip junction nozzle picks up the chip, and the chip is placed on the printed circuit board, the surface in the lower direction of the chip, or the height of the peak of each conductor metals which is called a bump, is position-corrected such that these are parallel to the upper surface of the printed circuit board, and further, the surface of the chip to be jointed or the height of the peak of each conductor metals, and the surface of the printed circuit board pattern can come into contact with each other while these are always keeping parallelism, can be pressed, and the junction by the ultrasonic can be conducted.
In the chip junction nozzle, the hardness of the surface of the mirror surface is preferably not less than HrC 40.
When the surface roughness of the mirror surface is expressed by the average roughness of the centerline, the average roughness of the centerline is preferably not more than 1.6 &mgr;m.
The slope is preferably a plane or a circular arc surface.
REFERENCES:
patent: 3575333 (1971-04-01), Kuicke et al.
patent: 3700155 (1972-10-01), Hermanns
patent: 4667870 (1987-05-01), Avedissian et al.
patent: 6189760 (2001-02-01), Gotoh et al.
patent: 59208844 (1985-03-01), None
patent: 01244630 (1989-12-01), None
patent: 04170035 (1992-09-01), None
patent: WO 01/24963 (2001-04-01), None
Gotoh Masashi
Kanazawa Jitsuo
Mizuno Toru
Okazaki Koichiro
Onozeki Yoshihiro
Elve M. Alexandra
TDK Corporation
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