Photography – Fluid-treating apparatus – Fluid application to one side only of photographic medium
Reexamination Certificate
2003-05-23
2004-03-02
Rutledge, Della J (Department: 2851)
Photography
Fluid-treating apparatus
Fluid application to one side only of photographic medium
C700S108000, C700S121000, C700S218000, C156S345320, C029S025010
Reexamination Certificate
active
06698944
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an exposure apparatus, a substrate processing unit and a lithographic system, and a device manufacturing method. More particularly, the present invention relates to an exposure apparatus used in a lithographic process when producing a semiconductor element, a liquid crystal display, a plasma display, a thin film magnetic head, an image pick-up device (CCD), a microdevice such as a micromachine, and furthermore, a photomask (reticle) and the like, a substrate processing unit which is in-line connected to the exposure apparatus, and a lithographic system which arrangement includes the exposure apparatus and the substrate processing unit, and a device manufacturing method employing the exposure apparatus and the lithographic system.
2. Description of the Related Art
In the lithographic process to produce a microdevice such as a semiconductor element and the like referred to above, various exposure apparatus were used in general. In recent years, the exposure apparatus that transfers a pattern formed on a mask or a reticle (hereinafter generally referred to as a “reticle”) onto a substrate such as a wafer or a glass plate (hereinafter generally referred to as a “wafer”) coated with a photoresist (photosensitive agent) via a projection optical system is mainly used. Of the exposure apparatus, the reduction projection exposure apparatus (the so-called stepper) based on the step-and-repeat method was the mainstream. However, the usage of the scanning type exposure apparatus (the so-called scanning stepper) based on the step-and-scan method, which performs exposure by synchronously scanning the reticle and the wafer in respect to the projection optical system, has lately increased.
The lithographic process includes a resist coating process to coat the resist onto the surface of the wafer and a development process to develop the wafer after completing the reticle pattern transfer, performed before and after the exposure process that uses the exposure apparatus. And in the resist coating process and the development process, a coating/development unit called a coater developer (hereinafter abbreviated as “C/D”) is used. This coater developer has the function of both a resist coating unit (a coater) such as a spin coater which, for example, spins the wafer at a high speed and utilizes the rotation of the wafer to evenly coat drops of resist dripped onto the surface of the wafer, or a scan coater which relatively moves the nozzle and the wafer, and a development unit (a developer).
In the lithographic process, a system arrangement, which is widely called as an in-line connection, is frequently employed. With the in-line connection, the C/D is arranged, for example, on the left, right, or the front (or the back) of the exposure apparatus and is connected directly or via a connecting portion to the exposure apparatus, and the body subject to processing (wafer subject to processing) is carried automatically in between the C/D and the exposure apparatus. The purpose for employing this system arrangement is to avoid complication when delivering the processing lot (the wafer lot subject to processing) to each of the resist coating process, the exposure process, and the development process, and to also improve the throughput while maintaining the chemical properties in the chemically amplified resist, which is a type of resist with high sensitivity frequently used nowadays.
In the lithographic system employing such an in-line connection between the exposure apparatus and the C/D, in most cases, a delivery portion is arranged in between the exposure apparatus and the C/D to perform delivery of the wafer between these units. In addition, the C/D has a carriage system within the unit that circulates the wafer subject to processing under a fixed process between the coating portion where the coating process is performed and the development portion where the development process is performed. The exposure apparatus also has a carriage system within the unit, and circulates the wafer subject to processing between the wafer stage where the exposure is performed and the delivery portion.
Moreover, with the lithographic process described above, in many cases, a cooling portion and a bake portion are arranged when necessary. Furthermore, a buffer portion to temporarily house the wafer subject to processing is also arranged when necessary.
In the lithographic system employing the in-line connection of the exposure apparatus and the C/D, when delivery of the wafer is performed at the delivery portion, the exposure apparatus and the C/D communicate with each other so that the delivery of the wafer is performed without fail. Therefore, the exposure apparatus and the C/D respectively have a control portion that performs communication and carriage control.
In the conventional lithographic system, however, the exposure apparatus and the C/D communicated on issues related to the delivery of the wafer at the delivery portion such as the delivery request, the possibility/forbiddance of delivery, and the completion of delivery and the like only real time, step by step.
This caused circumstances such as the exposure apparatus not being able to receive the wafer, when the C/D circulates the wafer under the fixed procedure so as to perform optimal carriage within the unit and tries to deliver the wafer that has not yet been exposed during the carriage to the exposure apparatus through the delivery portion. Or, the C/D could not receive the wafer that has completed exposure at the exposure apparatus side through the delivery portion, because the wafer had not yet arrived at the delivery portion. This situation led to a longer waiting time, and in some cases, the delivery ended in failure since no wafers were ready for delivery due to the difference in timing of the circulation carriage within the respective units, and the wafer carriage was suspended until the next circulation timing.
Whereas, with the exposure apparatus, the operation is efficient when the wafer is processed continuously on the wafer stage. Therefore, in order to avoid the situation where there are no wafers to process on the wafer stage as much as possible, the loading of the wafer onto the wafer stage and the unloading of the wafer from the wafer stage need to be performed alternately or simultaneously. With the wafers that have been exposed, the wafers need to be unloaded without the time spent on each wafer differing and sent to the next process of bake/development performed by the C/D as quickly as possible, since the chemical change of the wafer is continuous.
Considering such circumstances, the exposure apparatus side performs wafer carriage in the order of loading the wafer into the apparatus and then unloading the wafer outside the apparatus. There were times, however, when the exposure apparatus tried to receive the wafer that has not yet been exposed from the delivery portion but could not since the C/D side had not yet delivered the wafer, or, when the exposure apparatus tried to deliver the wafer that has completed exposure to the C/D through the delivery portion but could not since the C/D side was not in a state to receive the wafer. In these cases, the exposure apparatus waits for a certain period and monitors the situation to see if the wafer that has not yet gone through the exposure process is delivered. And if the wafer is not delivered and exposure process is completed at that stage, the exposure apparatus suspends the wafer loading, and switches the circulation operation to the unloading operation of the wafer that has completed the exposure process. Therefore, the situation occurred at times where the delivery ended in failure or where the exposure apparatus had to wait for delivery at the delivery portion.
The description above describes the case when the carriage system of the exposure apparatus performs the loading and unloading of the wafer alternately, however, even if the carriage system performs the loading simultaneously, the restrictions
Nikon Corporation
Rutledge Della J
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