Cleaning and liquid contact with solids – Processes – For metallic – siliceous – or calcareous basework – including...
Reexamination Certificate
1999-12-27
2001-02-27
El-Arini, Zeinab (Department: 1746)
Cleaning and liquid contact with solids
Processes
For metallic, siliceous, or calcareous basework, including...
C134S133000, C134S902000, C134S021000
Reexamination Certificate
active
06193807
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a substrate conveying device for conveying a substrate such as a semiconductor wafer or an LCD glass substrate, between a cassette and a processing unit.
Generally, in the manufacture of a liquid crystal display, photolithography is employed so as to form a circuit, an electrode pattern or the like, on a substrate such as a glass substrate. In the photo-lithography, a series of processing steps, namely, the washing and drying of a substrate, the formation of a resist film on the substrate, the exposure of the resist film, the development, and the like, are carried out. In the processing device for carrying out these processing steps, substrates unloaded from a cassette placed in the cassette station are conveyed to the processing unit one by one while being held on an arm, and the substrates are subjected to the processing steps including washing, one after another. After that, the substrates which have been processed at each processing unit, are conveyed back into the cassette one by one while being held on the arm.
However, with regard to the upper surface of the arm for conveying substrates, in the case where the section of the upper surface, for supporting an unwashed substrate, and the section for supporting a washed substrate are used in common, the following problem easily occurs. That is, when an unwashed substrate is placed on the arm, a contaminant attached to the rear surface of the unwashed substrate is transferred onto the supporting section of the arm, and the transferred contaminant may then easily be further transferred via the arm onto the rear surface of a washed substrate, while conveying the washed substrate on the arm. In order to solve the described problem, for example, Jpn. Pat. Appln. KOKAI Publication No. 5-152266 proposes a substrate conveying device. More specifically, in the substrate conveying device disclosed in Jpn. Pat. Appln. KOKAI Publication No. 5-152266, a substrate unloading arm for taking out an unwashed substrate from a cassette, and conveying it to the washing unit, and a substrate loading arm for returning a substrate finished with washing in the washing unit, to the cassette are formed to be separate mechanisms, so as to avoid the reattachment of a contaminant.
However, in the substrate conveying device disclosed in Jpn. Pat. Appln. KOKAI Publication No. 5-152266, which switches the substrate unloading arm and the processed substrate loading arm before and after washing, the entire arm is, for example, rotated, and therefore a wide space is required for fully moving the arm therein. Thus, the space of the device cannot be effectively used. Further, in the case where separate mechanisms are used as a substrate unloading arm, and a processed substrate loading arm as in the prior art substrate conveying device, separate loading and unloading arms must be prepared. Further, the drive mechanism for switching the loading and unloading arms is relatively large in size. Therefore, the entire structure becomes very complicated.
BRIEF SUMMARY OF THE INVENTION
The object of the present invention is to provide a substrate conveying device capable of avoiding, for example, the reattachment of a contaminant onto a substrate, with a simple structure, as well as a method therefor.
In order to achieve the above-described object, according to the first aspect of the present invention, there is provided a substrate conveying device for loading/unloading a substrate to/from a processing section, comprising:
an arm for holding the substrate;
an arm drive mechanism for driving the arm such as to load/unload the substrate to/from the processing section;
a first suction pad provided on the arm, for suctioning the substrate;
a second suction pad provided on the arm at a position adjacent to that of the first suction pad, for suctioning the substrate;
a projecting member provided between the first and second suction pads of the arm, so as to control a posture of the substrate to be suctioned one of the first and second suction pads as the projecting member abuts the lower surface of the substrate; and
a switching mechanism for selectively switching a mode between the first and second suction pads for suctioning the substrate by turning the arm over.
In the substrate conveying device, for unloading an unwashed substrate from a cassette, and conveying it to a processing section, the lower surface of the substrate is suctioned only by, for example, the first suction pad. By contrast, for returning a substrate washed in the processing section to a cassette, the lower surface of the substrate is suctioned only by, for example, the second suction pad. During this operation, the posture of a substrate is appropriately controlled by the projecting member, the substrate is not pressed against the first suction pad.
With the above-described structure, unwashed substrates and washed substrates can be held on the same arm but suctioned by different suction pads, the re-attachment of contaminant on a washed substrate can be prevented.
Further, it is preferable that the first and second suction pads should be formed of an elastically deformable material, and one of the first and second suction pads, which suctions the substrate should be elastically deformed such that the height thereof is lower than the other suction pad.
Furthermore, it is preferable that the first and second suction pads should be provided at a plurality of locations on both sides of an imaginary center line which corresponds to the periphery of the substrate, and one of the suction pads should be situated on the inner side of the substrate while the other pad should be situated on the outer side of the substrate.
According to the second aspect of the present invention, there is provided a substrate conveying device for loading/unloading a substrate to/from a processing section, comprising:
an arm, having one surface and another surface, for holding the substrate;
an arm drive mechanism for driving the arm such as to load/unload the substrate to/from the processing section;
a first suction pad provided on the one surface of the arm, for suctioning the substrate;
a second suction pad provided on the another surface of the arm for suctioning the substrate; and
a switching mechanism for selectively switching a mode between the first and second suction pads for suctioning the substrate by turning the arm over.
With the above-described structure, the first and second adsorption pads can be switched over by reversing the arm. Therefore, unwashed substrates and washed substrates can be held by the same arm, and still the contamination via the suction pad can be prevented.
According to the third aspect of the present invention, there is provided a substrate conveying method for conveying a substrate with use of a substrate conveying device including, an arm for holding the substrate thereon, first and second suction pads provided on the arm for selectively suctioning the substrate, a projecting member provided between the first and second suction pads of the arm; the method comprising the steps of:
loading an unwashed substrate in the processing section while holding the unwashed substrate with the first suction pad by suction and the projecting member abutting the lower surface of the unwashed substrate so as the unwashed substrate to be suctioned by the first suction pad; and
unloading a washed substrate from the processing section while holding the washed substrate with the second suction pad by suction and the projecting member abutting the lower surface of the unwashed substrate so as the unwashed substrate to be suctioned by the second suction pad.
According to the fourth aspect of the present invention, there is provided a substrate conveying method for conveying a substrate with use of a substrate conveying device including, an arm for holding the substrate thereon, first suction pad provided on one surface of the arm, second suction pad provided on another surface of the arm, and a switching mechanism for selectively switching a mode between
Iwasaki Tatsuya
Tateyama Kiyohisa
El-Arini Zeinab
Rader Fishman & Grauer
Tokyo Electron Limited
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