Photography – Fluid-treating apparatus – Fluid application to one side only of photographic medium
Reissue Patent
1999-09-02
2001-12-18
Rutledge, D. (Department: 2851)
Photography
Fluid-treating apparatus
Fluid application to one side only of photographic medium
C396S611000, C396S612000, C396S624000, C414S225010, C414S940000, C414S152000, C414S222130, C118S500000
Reissue Patent
active
RE037470
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to substrate processing apparatus and a substrate processing apparatus for processing a substrate such as a semiconductor wafer.
2. Description of the Related Art
In a photolithography process in manufacturing a semiconductor device, a resist coating process for coating a resist on a wafer and a developing process for developing a coated resist after an exposure process. These processes are simultaneously performed by using a composite process system described in, e.g., U.S. Pat. No. 5,339,128. This system comprises a main handler for conveying a wafer, and is designed such that a wafer W is loaded by the main handler from a cassette station into a process section, the wafer W are exchanged between process chambers in the process section, and the above processes are performed.
A conventional handler has an arm section driven by three axes (Y axis, Z axis, and &thgr; rotation axis), and the arm section a plurality of holding arms driven by only the X axis. All the 4-axis drive operations in the main handler are independently (individually) performed. For example, the arm section of the main handler moves in the Y-axis direction first, moves in the Z-axis direction, and then rotated at the angle &thgr;. Finally, the holding arms move in the X-axis direction to receive a wafer.
In recent years, a demand for an increase in a throughput for a resist coating/developing process system is strong. For this reason, in order to answer this demand, the main handler must be operated at a speed as high as possible in a process section. However, since the 4-axis drive operations in the X-axis direction, Y-axis direction, Z-axis direction, and &thgr;-rotation-axis direction are independently performed in the conventional main handler, the speed of the main handler operation is limited to a certain speed. The main handler performs sequential operations, e.g., the start of moving in the Y-axis direction, the end of the moving of the Y-axis direction, the start of moving in the Z-axis direction, the end of the moving of the Z-axis direction, the start of moving in the &thgr;-rotation-axis direction, the end of the moving of the &thgr;-rotation-axis direction, the start of moving in the X-axis direction, and the end of the moving of the X-axis direction. Therefore, a time from when the main handler reaches a target point to when the main handler receive a wafer is too long so that it is very difficult to increase the throughput.
In addition, when each drive system employs a high-speed drive mechanism to more increase the operation of the main handler, an excessive load acts on the mechanism, its durability and reliability may be degraded. In addition, when the operation speed of each drive system is increased, a noticeable amount of particle is generated, the wafer is contaminated by attaching particle on the wafer, and a yield may be decreased.
When a resist solution such as polyimide having a high viscosity is used in a resist coating process, even after a side rinse process in a coating device, the resist is not completely removed from the wafer peripheral portion, and the resist may be partially left on the wafer peripheral portion. When the residual resist is attached to the holding arms of the main handler, the wafer W is easily removed from the holding arms, and the wafer W cannot be smoothly conveyed. For this reason, the contact area between the wafer peripheral portion and the holding arms shall be minimized.
In a conventional method of conveying a wafer, independently of the distance between a main handler and a target point, the main handler is moved at a constant acceleration and a constant deceleration. For this reason, the distance between the main handler and the target point is long, the torque of a servo motor instantaneously, excessively varies at the start of the servo motor, vibration from the servo motor may be transmitted to the main handler. When the main handler vibrates, the contact state between the holding arms and the wafer W changes, and resist residue easily moves to the holding arms.
In a process using a resist solution having a low viscosity, it may be impossible to perform a side rinse process. For this reason, a wafer W on which a resist is coated is conveyed, the resist is attached to the holding arms due to vibration. This attached resist is dried soon and removed from the holding arms, thereby generating particles. In this manner, the wafer is contaminated by the particles, and a production yield is decreased.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a substrate processing apparatus and a substrate processing method in which a substrate can be conveyed as a whole within a short time without causing an excessive load to act on each drive mechanism to increase a throughput and to suppress generation of particles.
It is another object of the present invention to provide a substrate processing apparatus and a substrate processing method in which vibration generated during convey of a substrate can be suppressed, and a convey method can be selected depending on the conditions of the substrate.
According to the present invention, there is provided to a substrate processing apparatus for performing a plurality of processes to a substrate comprising:
a common path, extending in a Y-axis direction, in which one substrate or a plurality of substrates are conveyed;
a plurality of process units stacked on both sides of the common path to constitute multi-stage structures;
a main handler moved in the common path in the Y-axis direction and rotated about a Z axis at an angle &thgr; to load/unload the substrate into/from the process units;
an arm section arranged to move in the main handler in the Z-axis direction;
a plurality of holding arms arranged in the arm section to constitute a multi-stage structure so as to respectively hold the substrates, each holding arm being advanced and retreated on an X-Y plane from the arm section;
detection means, arranged in the arm section, for detecting a holding state of the substrate held in each of the plurality of holding arms; and
control means for controlling an operation of the main handler, an operation of the arm section, and operations of the plurality of holding arms on the basis of a detection result from the detection means,
wherein the control means advances or retreats each holding arm while operating at least one of the main handler and the arm section, and causes the detection means to detect the holding state of the substrate held by each holding arm before the holding arm reaches a corresponding one of the process units.
The main handler, the arm section and the holding arms of the above apparatus various multi-axis synchronous drive operations such as (1) to (3) can be executed.
(1) A synchronous operation of Z-axis direction moving/&thgr; rotation is started, X-axis direction moving is started, a synchronous operation of Z-axis direction moving/&thgr; rotation is completed, and the X-axis direction moving is completed.
(2) Z-axis direction moving is started first, &thgr; rotation is started, and a synchronous operation of Z-axis direction moving/&thgr; rotation is completed.
(3) &thgr; rotation is started first, Z-axis direction moving is started, and a synchronous operation of Z-axis direction moving/&thgr; rotation.
In each of all the operations, a time required to convey a wafer is shorter than that in the conventional sequential operations. A whole convey time can be adjusted to a longer one of a time required for Z-axis direction moving and a time required for &thgr; rotation. In this manner, the wafer can be rapidly conveyed at a rated moving speed within a time shorter than a time required in the conventional operation. Furthermore, an amount of particle generation can be suppressed.
A period of time until a substrate intrudes into an interference area of the process unit such as the target point, the holding arms can be synchronously advanced and retreated during moving of the main handler
Iida Naruaki
Kudou Hiroyuki
Ohkura Jun
Sakamoto Yasuhiro
Tateyama Masanori
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Rutledge D.
Tokyo Electron Limited
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