Heating – Accessory means for holding – shielding or supporting work... – Support structure for heat treating ceramics
Reexamination Certificate
2001-11-23
2003-06-24
Wilson, Gregory (Department: 3749)
Heating
Accessory means for holding, shielding or supporting work...
Support structure for heat treating ceramics
C438S459000, C438S460000
Reexamination Certificate
active
06582223
ABSTRACT:
This nonprovisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2000-358571 filed in Japan on Nov. 24, 2000, which is herein incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pickup apparatus for separating semiconductor chips from an adhesive sheet.
2. Description of the Related Art
A production process of a semiconductor device is divided into first and second steps. In the first step, circuit components are formed on a semiconductor wafer. In the second step, the semiconductor wafer including the circuit components is diced into separate semiconductor chips, and the diced semiconductor chips are sealed in respective semiconductor packages.
In the second step, in order to convey the semiconductor chips obtained by dicing the semiconductor wafer to a packaging apparatus, a pickup apparatus picks up the semiconductor chips from an adhesive sheet used for fixing the semiconductor chips. Examples of conventional pickup apparatuses are as follows.
CONVENTIONAL EXAMPLE 1
FIG. 4
illustrates one of the conventional pickup apparatuses. This pickup apparatus includes a pushup unit
8
provided with pushup pins
7
, and an aspiration mechanism, i.e., a vacuum mechanism (not shown). Firstly, the pickup apparatus brings a back face of an adhesive sheet
2
into contact with the pushup unit
8
and causes the adhesive sheet
2
to be held on the pushup unit
8
using the aspiration mechanism. Next, the pushup pins
7
housed in the pushup unit
8
are raised so as to push up a back face of a semiconductor chip
1
, whereby the semiconductor chip
1
is separated from the adhesive sheet
2
. Finally, the semiconductor chip
1
is picked up using a collet
6
.
CONVENTIONAL EXAMPLE 2
Japanese Laid-Open Publication No. 2000-195877 discloses a pickup apparatus illustrated in FIGS.
5
(
a
), (
b
), and (
c
). As illustrated in FIG.
5
(
a
), this conventional pickup apparatus includes: a sheet holding mechanism (not shown) for holding a dicing sheet
13
(corresponding to the adhesive sheet
2
illustrated in
FIG. 4
) to which a semiconductor chip
11
is attached when the dicing sheet
13
is in a stretched state; a holding stage
12
in which grooves
12
a
connected to a plurality of aspiration paths (through holes)
12
b
(in FIGS.
5
(
a
), (
b
) and (
c
), a distance between rightmost and leftmost paths corresponds to a length of the semiconductor chip
11
); and an aspiration mechanism, i.e., a vacuum mechanism (not shown) for vacuum-holding the dicing sheet
13
to the holding stage
12
when separating the semiconductor chip
11
from the dicing sheet
13
. In order to pick up the semiconductor chip
11
attached to the dicing sheet
13
using this conventional pickup apparatus, at first, the aspiration mechanism is operated so as to vacuum-hold the dicing sheet
13
to the holding stage
12
along the grooves
12
a
, so that as illustrated in FIG.
5
(
b
), gaps are made between the semiconductor chip
11
and the dicing sheet
13
, and the semiconductor chip
11
is caused to be easily separated from the dicing sheet
13
. Thereafter, the semiconductor chip
11
is picked up using a collet
14
as illustrated in FIG.
5
(
c
).
In this conventional pickup apparatus, the grooves
12
a
of the holding stage
12
are in the form of either concentric circles (
FIG. 6
(
a
)), parallel lines (
FIG. 6
(
b
)) a grille (
FIG. 6
(
c
)) etc. The form of the grooves
12
a
can be suitably selected from these forms according to an external form of the semiconductor chip
11
so as to cause the semiconductor chip
11
to be easily peeled off the dicing sheet
13
. In this conventional technique, since the holding stage
12
is replaced with another holding stage
12
of a suitable size according to a type of a semiconductor chip, e.g., a difference in size between different types of semiconductor chips, the grooves
12
a
are provided in the holding stage
12
across almost an entire surface thereof. The structures of Conventional Examples 1 and 2 have the following problems.
In the structure of Conventional Example 1 (FIG.
4
), the pushup pins
7
which are sufficiently sharp so as to pierce the adhesive sheet
2
are required, and since such sharp pushup pins
7
push up the semiconductor chip
1
, the back face of the semiconductor chip
1
is likely to be damaged. In particular, by supporting the semiconductor chip
1
on a few points, such as the pushup pins
7
, stress is concentrated on those specific portions of the semiconductor chip
1
, so that the semiconductor chip
1
may be damaged. In the case where the semiconductor chip
1
is thin, the semiconductor chip
1
can be cracked by the pushup action of the pushup pins
7
.
In the structure of Conventional Example 2 (FIGS.
5
(
a
)-(
c
) and
6
(
a
)-(
c
)), a size of the holding stage
12
is optimized according to a size of the semiconductor chip
11
to be picked up. However, in the case where undulating grooves
12
a
are provided in the holding stage
12
across almost the entire surface thereof, other semiconductor chips adjacent the semiconductor chip
11
partially overlap with the holding stage
12
in areas
20
indicated by oblique lines in
FIG. 7
, so that not only is the semiconductor chip
11
separated from the dicing sheet
13
, but also the other semiconductor chips adjacent the semiconductor chip
11
may be caused to be partially separated from the dicing sheet
13
, where these other semiconductor chips should be fixed firmly to the dicing sheet
13
until they are meant to be picked up. Accordingly, it is possible for the other semiconductor chips adjacent the semiconductor chip
11
to be completely separated from the adhesive sheet
13
and scattered about when a semiconductor wafer including the semiconductor chips is moved. Since a size of an aspiration unit including the holding stage
12
cannot be small under restrictions of the pickup apparatus, in particular, when the size of the semiconductor chips is small, the other semiconductor chips adjacent the semiconductor chip
11
may be scattered about. This particularly causes a problem when the pickup apparatus is operated by automation.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a semiconductor chip pickup apparatus including an aspiration section and an aspiration unit connected to the aspiration section, in which the aspiration unit includes a stage for mounting the semiconductor chip thereon and an adhesive sheet is attached to the semiconductor chip between the stage and the semiconductor chip, the stage includes undulations in at least a part of an area in which the semiconductor chip is mounted, and by operating the aspiration section, a suction force is applied to at least a part of an area in which the undulations are formed.
According to one embodiment of the invention, the stage may be replaceable according to a type of the semiconductor chip.
According to another embodiment of the invention, at least a part of the stage including at least a part of the undulations may be formed of a porous material.
According to still another embodiment of the invention, at least one through hole may be formed in the area in which the undulations are formed.
According to still another embodiment of the invention, the pickup apparatus may further include a heating section for heating the undulations provided in the stage.
Hereinafter, functions of the semiconductor chip pickup apparatus of the present invention are described.
The semiconductor chip pickup apparatus of the present invention includes the aspiration section and the aspiration unit connected to the aspiration section. In a structure of the semiconductor chip pickup apparatus, by operating the aspiration section, a suction force is applied to at least a part of the undulations which are at least a part of an area formed in a stage of the aspiration unit in which a semiconductor chip is mounted. The aspiration section is operated so as to aspirate an
Goto Yasuhiro
Into Tadayuki
Ishioka Tatsuyuki
Iwasaki Noriki
Yasumura Hiroshi
Sharp Kabushiki Kaisha
Wilson Gregory
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