Work holders – With fluid means – Vacuum-type holding means
Reexamination Certificate
2001-01-17
2003-01-14
Hail, III, Joseph J. (Department: 3723)
Work holders
With fluid means
Vacuum-type holding means
C228S004500, C228S006200
Reexamination Certificate
active
06505823
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a method and apparatus for positioning semiconductor pellet in a die bonding apparatus, tape bonding apparatus, bump bonding apparatus or the like.
2. Prior Art
In a die bonding apparatus, tape bonding apparatus, bump bonding apparatus or the like, a semiconductor pellet is removed from a tray or wafer and placed on a positioning stage, and once placed on this positioning stage, the semiconductor pellet is positioned by a positioning claw. After this, in a die bonding apparatus, the semiconductor pellet is bonded to a lead frame. In a tape bonding apparatus, the semiconductor pellet is bonded to a carrier tape. In a bump bonding apparatus, a bump is formed on an electrode of the semiconductor pellet. In other words, in these bonding apparatuses, the semiconductor pellet is positioned prior to bonding or the formation of a bump.
Operations in these bonding apparatuses will be described below in more detail.
As shown in
FIG. 5
, a die bonding apparatus has a positioning stage
51
for holding a semiconductor pellet
50
by means of a suction hole
51
a,
a positioning claw
52
for positioning the semiconductor pellet
50
on the positioning stage
51
, a frame feeder
54
for conveying and positioning a lead frame
53
, and a bonding device
60
for bonding the semiconductor pellet
50
to the lead frame
53
. The positioning claw
52
is provided on an XY table
55
which is driven in the X and Y directions. In the bonding device
60
, a bonding head
62
is mounted on an XY table
61
that is driven in the X and Y directions, and a bonding arm
63
is provided on the bonding head
62
so as to be moved up and down. A bonding tool
64
is provided on the distal end of the bonding arm
63
. This bonding tool
64
is in the form of a suction nozzle that holds the semiconductor pellet
50
by suction.
This type of die bonding apparatus is disclosed in, for instance, Japanese Patent Application Laid-Open (Kokai) Nos. H4-61241 and H4-312936.
When the semiconductor pellet
50
is placed on the positioning stage
51
, it is held by suction on the positioning stage
51
. Then, the XY table
55
is driven to move the positioning claw
52
toward the semiconductor pellet
50
, and the semiconductor pellet
50
is positioned by the positioning claw
52
. Next, the XY table
61
of the bonding device
60
is moved in the Y direction so as to be above the semiconductor pellet
50
on the positioning stage
51
, and the bonding tool
64
is lowered to hold the semiconductor pellet
50
. The bonding tool
64
is then raised, moved to above the bonding position of the lead frame
53
, and then lowered, thus bonding the semiconductor pellet
50
to the lead frame
53
.
As to a tape bonding apparatus, and particularly an inner lead bonding apparatus, it is structured, as shown in
FIG. 6
, more or less the same as the die bonding apparatus shown in FIG.
5
. In this inner lead bonding apparatus of FIG.
6
. however, the positioning claw
52
does not move; and instead the positioning stage
51
is mounted on the XY table
55
, and the positioning stage
51
is moved to beneath a carrier tape
65
by the XY table
55
. Also, the bonding tool
64
is not a suction nozzle and is shaped such that a lead provided on the carrier tape
65
will be pressed against the semiconductor pellet
50
.
Japanese Patent Application Laid-Open (Kokai) No. H2-244735 discloses this type of tape bonding apparatus.
When a semiconductor pellet
50
is placed on the positioning stage
51
, it is held by suction on the positioning stage
51
. The XY table
55
is driven to move the positioning stage
51
toward the semiconductor pellet
50
, and the semiconductor pellet
50
is positioned by the positioning claw
52
. The XY table
55
is then driven to move the positioning stage
51
to beneath the carrier tape
65
, after which the lead of the carrier tape
65
is pressed against and bonded to the semiconductor pellet
50
by the bonding tool
64
of the bonding device
60
.
As to a bump bonding apparatus it is also, as shown in
FIG. 7
, structured more or less the same as the die bonding apparatus shown in FIG.
5
. In this bump bonding apparatus, however, the positioning stage
51
doubles as a bonding stage, and a wire bonding device is usedas the bonding device
60
. Therefore, a very fine (20 to 30 &mgr;m) wire of gold or solder (not shown) is passed through the bonding tool
64
.
When the semiconductor pellet
50
is placed on the positioning stage
51
, it is held by suction on the positioning stage
51
. The XY table
55
is driven to move the positioning claw
52
toward the semiconductor pellet
50
, and the semiconductor pellet
50
is positioned by the positioning claw
52
provided on the XY table
55
. A bump is then formed on an electrode of the semiconductor pellet
50
by the bonding device
60
. In this bump formation method, a ball formed at the distal end of the wire passing through the bonding tool
64
is pressed against the electrode of the semiconductor pellet, the wire is cut at the base of the ball, and a bump is formed on the electrode of the semiconductor pellet.
An example of this type of bump bonding apparatus can be found in Japanese Patent Application Laid-Open (Kokai) No. H7-86286.
In the above bonding apparatuses, the semiconductor pellet
50
is moved by the positioning claw
52
during the positioning process; accordingly, it is necessary that the positioning stage
51
holds the semiconductor pellet
50
with a weak suction force that allows the semiconductor pellet
50
to be moved. However, since the semiconductor pellet
50
is kept held by this weak suction force in the above bonding apparatuses, there is the danger that the semiconductor pellet
50
is misaligned due to vibration or other reasons as described below.
More specifically, in the die bonding apparatus shown in
FIG. 5
, the semiconductor pellet
50
positioned by the positioning claw
52
is moved over the lead frame
53
by being held by the bonding tool
64
; accordingly, much of a problem would not occur. In the case of the tape bonding apparatus shown in
FIG. 6
, however, the positioning stage
51
and the semiconductor pellet
50
held thereon are moved to beneath the carrier tape
65
; accordingly, the semiconductor pellet
50
is susceptible to misalignment during this movement. In addition, in the case of the bump bonding apparatus shown in
FIG. 7
, since the formation of the bump is performed by the bonding device
60
on the semiconductor pellet
50
held on the positioning stage
51
, the semiconductor pellet
50
is susceptible to misalignment during this bump formation.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention is to provide a semiconductor pellet positioning method and apparatus that prevent the misalignment of a semiconductor pellet once it has been positioned.
The method of the present invention for accomplishing the above object is a semiconductor pellet positioning method in which a positioning stage for holding a semiconductor pellet is moved relative to a positioning claw, and the semiconductor pellet is positioned by the positioning claw; and in the present invention during the positioning of the semiconductor pellet, the semiconductor pellet is held on the positioning stage by a suction force that is weak enough so that the positioning claw can move the semiconductor pellet, and upon completion of the positioning, the semiconductor pellet is held on the positioning stage by a suction force that is stronger than suction force used during the positioning.
The apparatus of the present invention for accomplishing the above object is a semiconductor pellet positioning apparatus that comprises a positioning stage for holding a semiconductor pellet and a positioning claw for positioning the semiconductor pellet by moving relative to this positioning stage; and in the present invention, a suction force control means is further provided so that the semiconductor pellet is held on
Moroe Hirofumi
Ushiki Hiroshi
Hail III Joseph J.
Kabushiki Kaisha Shinkawa
Koda & Androlia
Shanley Daniel
LandOfFree
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