Cylinder, load port using it, and production system

Details Cylinder, load port using it, and production system Cylinder, load port using it, and production system

2001-10-31

2003-11-25

Lillis, Eileen D. (Department: 3652)

Material or article handling

Apparatus for moving material between zones having different...

C414S940000, C292S059000, C250S239000

Reexamination Certificate

active

06652212

ABSTRACT:

BACKGROUND OF INVENTION
1. Field of Invention
This invention relates to a cylinder, a load port using it and a production system using the load port, and in particular, to a load port which complies with the SEMI standard and is suitable for FOUPs (Front Opening Unified Pods) having a variety of latchkey receptacle shapes.
2. Description of the Related Art
Until now, open cassettes have been mainly used as a container which stores a plurality of semiconductor wafers. However, in order to reduce the production cost of high-performance semiconductor devices, the mini-environment systems have been advocated, which reduce the cost related to a clean room. In the mini-environment systems, the SMIF (Standard Mechanical Interface) system is widely used for 200 mm-wafers, and the FOUP (Front Opening Unified Pod) system is being examined to be used for 300 mm-wafers.
The FOUP system was advocated and provisionally standardized at SEMI (Semiconductor Equipment and Materials International) composed of semiconductor manufacturing equipment manufacturers and material manufacturers all over the world. Semiconductor device manufacturers are also preparing to construct the mass-production line with this system. The FOUP system was technically examined at the standard committee of SEMI and was provisionally standardized. Here, the SEMI standard E57-0299 strictly defines the accuracy of the load port mechanical interface method to open and close an FOUP door; on the other hand, it allows FOUP manufacturers more latitude in adopting mechanical interface of FOUP.
The FOUP system, for example, is described in detail in JP8-279546A. The structure and the opening and closing mechanism of FOUP are explained by referring to
FIGS. 12 and 13
.
FIG. 12
is a perspective view of a load port carrying out the opening and closing of FOUP door. Here, load port
30
is composed of frame
31
having a opening, stage
32
which is enable to move in the frame direction and has three kinematic pins
34
on the surface, and port door
33
which is inserted into the opening from opposite direction to stage
32
and retracted from the opening. In port door
33
, two registration pins
36
are mounted diagonally, and two latchkeys
35
that rotate between the vertical position (90-degree position) and the horizontal position (0-degree position) are installed. Additionally, holding pads
37
are installed surrounding respective registration pins
36
to fix FOUP door
52
to port door
33
.
FOUP
50
is composed of FOUP box
51
and FOUP door
52
, as is shown in FIG.
13
. FOUP box
51
has a plurality of shelves to hold wafers
53
and handles
58
for carrying by hand. In FOUP door
52
, latch holes
55
and registration holes
54
are formed at corresponding positions to latchkeys
35
and registration pins
36
of port door
33
. Inside latch holes
55
, a latchkey receptacle is installed to engage with latchkey
35
. The locking and unlocking operation of latches
56
is carried out by turning the latchkey receptacles using the latchkeys.
It is stipulated in the SEMI standard that fixing and unfixing of FOUP door
52
to and from FOUP box
51
is made by turning the latchkey receptacles to the positions of the 90-degree and the 0-degree, respectively. However, there is no concrete stipulation on the fixing method of FOUP door, and therefore, FOUP manufacturers are allowed to adopt their own method. The opening and closing mechanism of FOUP door is described in, for example, U.S. Pat. No. 5,915,562.
One of the FOUP opening and closing operations will be explained below. An FOUP is placed on stage
32
having three kinematic pins
34
mounted thereon and is aligned with the aid of the kinematic pins. Then, stage
32
is moved forwards to insert registration pins
36
of the port door into registration holes
55
of FOUP
50
, whereby the FOUP door is positioned against the port door. Further advance of the stage makes latchkeys
35
of the port door engage with latchkey receptacles through latch holes
55
of FOUP, and the FOUP door finally contacts with the port door. At this stage, the inside of holding pads
37
installed around the root of registration pins
36
are evacuated to fix the FOUP door to the port door.
Then, the FOUP door is detached from the FOUP box by turning latchkeys 90 degrees to the 0-degree position. The port door, holding the FOUP door, is moved backwards and then downwards. Thus, wafers can be taken out through the opening. Each wafer stored in the FOUP box is transferred by e.g. a scalar type robot disclosed in JP No.2749314 to a wafer process tool.
When the FOUP door is closed, the same operation is made in reverse order.
This FOUP system was established as a provisional specification of SEMI in 1996, and each company has developed and manufactured FOUPs and load ports on the basis of this standard. Various disadvantages about the FOUP system have been clarified with advancing the verification of operation.
As mentioned above, there is few stipulation on FOUP, in spite of strict stipulation on the load port: for example, the shape and size of latchkey are defined including their tolerance, but those of latchkey receptacle are not. Therefore, the following problems have arisen. According to the SEMI standard E62-0999, the tolerance on the rotation angle of latchkey is defined as ±1 degree at the 0-degree position and 90-degree position. However, since there is no stipulation on the size of the latchkey receptacle, latchkey receptacles may not rotate 90 degrees even if latchkeys rotate by 90 degrees, as shown in FIG.
8
(A), in the case where the width W
1
of latchkey receptacles
57
is to some extent larger than the width W
2
of latchkey
35
. That is, latchkey receptacles may not rotate to the 90-degree position, but to the (90−&thgr;) degree position depending on the difference of (W1-W2), which results in failing to lock the latches. The latchkey receptacles happen not to be at the 90-degree position even though the latches have been locked. When this FOUP is transported to the load port of next process tool and the stage thereof is moved forwards to open the FOUP, the latchkeys may contact or collide with latchkey receptacles of the FOUP door. The contact or collision causes dust generation and contaminates the wafer transferring space. Furthermore, the repetition of the contact and collision may deform the latchkey receptacles and finally destroy the FOUP door. If the latchkey receptacle is deformed, they cannot rotate to the 0-degree position when latchkeys rotate to the 0-degree position. Thus, latchkey receptacles will stop at e.g., 5 degrees that is out of tolerance range of ±1 degree. As a result, the FOUP door cannot be detached from FOUP box, which is a severe disadvantage in the manufacturing process of semiconductor devices and the like.
Although each FOUP manufacturer has carried out various examinations in order to solve the above problems, the appropriate solution has not been obtained from the viewpoint of cost and reliability.
Then, the inventors have developed the load port which can make latchkey receptacles into the 90-degree position by rotating the latchkeys more than 90 degrees when to lock the latches (Japanese Patent Application 2000-59654). This makes possible the stable latching operation. However, it was found in the case of the production system including a conventional load port that the latchkey receptacle angle often greatly deviated from 90 degrees depending on the type of FOUP and that the latchkey contacted the latchkey receptacle to damage. This will be explained using FIG.
14
.
FIG. 14
is a graphical representation showing the latchkey receptacle angles for two types of FOUP after latches are locked. Here, the production system is composed of conventional load ports (C and G) and new type load ports (A, B, D, E, F, and H). The latchkey receptacles were made at almost 90 degrees for any FOUP when the latches were locked using the new type load port (A, B, D, E, F, and H), but they happened to be at about 86 degrees when the

Affiliated with

Also associated with

Rating

Cylinder, load port using it, and production system does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Cylinder, load port using it, and production system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cylinder, load port using it, and production system will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3182177