Conveyors: power-driven – With means to facilitate working – treating – or inspecting... – Means engaging conveyor or load on a conveyor to align load...
Reexamination Certificate
2001-05-31
2003-09-30
Valenza, Joseph E. (Department: 3651)
Conveyors: power-driven
With means to facilitate working, treating, or inspecting...
Means engaging conveyor or load on a conveyor to align load...
C198S345300
Reexamination Certificate
active
06626280
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a tray-positioning device and in particular relates to a tray-positioning device that utilizes the upper sidewalls of a tray for positioning. Having no mold lines or deformations commonly found on the lower sidewalls of a tray, the upper sidewalls possess smoother surfaces. Hence the tray-positioning device in the present invention is capable of providing higher degree of precision for tray positioning.
BACKGROUND OF THE INVENTION
Having undergone hundreds of processing steps, a semiconductor wafer is divided into a plurality of dies before being tested and packaged for delivery. To facilitate handling and management, dies are contained and carried around in a designated tray.
FIG. 1
shows a perspective view of a tray
1
for containing dies
2
. Being square-slab shaped, said tray
1
possesses a total of four stair-contoured sides, each having a lower sidewall
12
and an upper sidewall
14
such that the upper sidewall
14
is situated on the inner side and above the lower sidewall
12
. Said tray
1
provides a number of slots
16
, each capable of containing a die
2
. The step for transferring die
2
to slot
16
is loading.
In order to raise loading speeding and avoid human contact, most semiconductor plant uses robot arm for loading. If tray positioning is not accurate, the robot arm could not place individual dies on individual slots precisely as programmed.
To point out the importance of tray positioning, the loading process in die sorter is illustrated in the following.
FIG. 2
shows a perspective view of a prior art die sorter
3
, which comprises a die tray
32
, a conveyor
34
, a push unit
36
and a robot arm
38
. Said die tray
32
is designated to hold a number of dies
2
, being divided from semiconductor wafers, for loading. Said conveyor
34
provides an input terminal
341
, an output terminal
342
and a sorter position
343
. By placing an empty tray
1
on conveyor
34
at terminal
341
and having it carried to the sorter position
343
for loading, followed by sending out an full stray
1
at output terminal
342
after said empty tray
1
is filled with dies. Said conveyor
34
can deliver one or a plurality of trays
1
, depending on the programmed loading operation. Prior art die sorter
3
as disclosed in
FIG. 2
is useful for delivering a first tray
1
and a second tray
1
a.
Being L-shaped, said push unit
36
includes a pivot
361
and a push rod
362
, wherein said pivot
361
is located on one side of the conveyor
34
and said push rod
362
is situated above the conveyor
34
and at an angle with respect to the horizontal position. Knowing that the conveyor
34
can only deliver the first tray
1
and the second tray
1
a
to the ballpark sorter position
343
, pivot
361
will cause the push rod
362
to turn to a horizontal position and drive push rod
362
so as to push the second tray
1
a,
located behind the first tray
1
, and the first tray
1
to the ballpark sorter position
343
, simultaneously.
Said robot arm
38
is capable of loading dies by picking up die
2
from die tray
32
and placing it onto slot
16
until all slots of the first tray
1
and the second tray
1
a
are filled with dies
2
.
Being a plastic material, the first tray
1
's lower sidewall
12
often includes mold lines with rough surface. Being the outer rim of tray
1
, the lower sidewall
12
is prone to deformation caused by collision or heat. Using the lower sidewall
12
, which lacks the smooth surface, for positioning, the prior art tray
1
is incapable of being positioned accurately at the exact sorter position
343
, hence preventing the robot arm from loading individual dies precisely and causing production losses.
SUMMARY OF THE INVENTION
Aimed at resolving the above disadvantage, the main object of the present invention is to provide a tray-positioning device capable of utilizing the smoother upper sidewall, which has no mold lines or deformations commonly found on the lower sidewalls of a tray, for precision positioning.
The following Description and Designation of Drawings are provided in order to help understand the features and content of the present invention.
REFERENCES:
patent: 3638564 (1972-02-01), Prange et al.
patent: 4255077 (1981-03-01), Smith
patent: 4302919 (1981-12-01), Hartness
patent: 4898268 (1990-02-01), Kamioka et al.
patent: 5829571 (1998-11-01), Mizuta et al.
Huang Chao-Hsien
Jane Shyan-Haur
Lai Chun-Kuei
Lin Chih-Min
Liu Chin-Yuan
Industrial Technology Research Institute
Troxell Law Office PLLC
Valenza Joseph E.
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