Optics: measuring and testing – Lamp beam direction or pattern
Reexamination Certificate
2001-03-22
2004-02-10
Smith, Zander V. (Department: 2877)
Optics: measuring and testing
Lamp beam direction or pattern
C356S218000
Reexamination Certificate
active
06690455
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an illuminance measurement apparatus and exposure apparatus, more particularly relates to an illuminance measurement apparatus used for measuring relative illuminances among a plurality of exposure apparatuses and an exposure apparatus provided with such an illuminance measurement apparatus, an exposure apparatus able to detect an exposure beam or a beam other than one used for exposure of a substrate, and a method of production of a device using such an exposure apparatus.
2. Description of the Related Art
When producing a semiconductor device or liquid crystal display device etc., a projection exposure apparatus is used for transferring a pattern drawn on a mask or reticle (hereinafter also referred to all together as a “mask”) or other master on to a semiconductor wafer or transparent substrate coated with a resist or other photosensitive substrate. The production lines for semiconductor devices or liquid crystal display devices do not use single projection exposure apparatuses. In general, a plurality of projection exposure apparatuses are used together.
In such a case, to reduce the variations in products made by the different exposure apparatuses, it is necessary to match the exposure quantities among the exposure apparatuses. For this purpose, an internal photo sensor (integrator sensor etc.) is provided in each exposure apparatus. This measures the illuminance on the image plane indirectly. The exposure quantity is matched among the exposure apparatuses based on the results of measurement. The internal photo sensor provided in each exposure apparatus, however, does not always detect the accurate illuminance. Error sometimes occurs along with the elapse of time etc. It is therefore necessary to calibrate the internal photo sensors.
Further, to coordinate the throughputs of processing of the different exposure apparatuses, it is necessary to centrally manage the relative illuminances.
Therefore, an inter-apparatus illuminance meter has been used to measure the relative illuminance among exposure apparatuses. This illuminance meter is designed to be able to be freely attached to a special mount (adapter) provided near a wafer holder of a wafer stage. A worker manually attaches (plugs in) the illuminance meter to the adapter and directly measures the illuminance on the image plane. After finishing the measurement of the illuminance, the worker detaches the illuminance meter from the adapter, then successively performs the same work on other exposure apparatuses so as to measure the illuminance of the exposure apparatuses.
Various cables such as the cable for the supply of power and the cable for transmission of a signal for reading the result of measurement of the illuminance meter are connected to the illuminance meter. These cables obstruct movement or break at the time of movement of the wafer stage making measurement of the illuminance impossible. Alternatively, time is required for restoration. Sometimes the down time of the exposure processing becomes longer. Further, a sensor used for measurement of the illuminance distribution, sensors used for measurement of the alignment or the optical characteristics of the projection optical system, etc. are also provided on the wafer stage. There are similar problems with such sensors. Further, the same is true when providing a sensor for receiving exposure illumination light at the reticle stage.
SUMMARY OF THE INVENTION
An object of the present invention is to enable reliable measurement of the illuminance within a predetermined time.
Another object of the present invention is to enable the reliable detection of illumination light even if at least some of the photodetectors receiving illumination light for exposure or illumination light used for other than exposure of the substrate are provided on a moving member.
To achieve the above object, the illuminance measurement apparatus of the present invention is an illuminance measurement apparatus for measuring the illuminance of illumination light on an image plane of a projection optical system of an exposure apparatus designed to project the image of a pattern from an illuminated mask on a substrate held on a substrate stage by the projection optical system, comprising an illuminance meter having an illuminance detector and a transmitter for wirelessly transmitting the measurement results of the illuminance detector and attached detachably to the substrate stage and a receiver for receiving a wireless signal including the measurement result transmitted from the transmitter.
According to the illuminance measurement apparatus of the present invention, since the measurement results of the illuminance detector are wirelessly transmitted, there is no longer the need to connect cables for transmitting the measurement results to the illuminance detector. Therefore, even if the illuminance meter is moved, it is possible to prevent obstacles to movement, breakage, etc. arising due to connection of the cable and possible to reliably measure the illuminance.
Further, to achieve the above object, the illuminance measurement apparatus of the present invention is an illuminance measurement apparatus for measuring the illuminance of illumination light on an image plane of a projection optical system of an exposure apparatus designed to project the image of a pattern from an illuminated mask on a substrate held on a substrate stage by the projection optical system, wherein the illuminance meter has a storage cell and a photoelectric converter for converting at least part of the illumination light photoelectrically and storing it in the storage cell.
According to the illuminance measurement apparatus of the present invention, since part or all of the illumination light is converted photoelectrically and stored in a storage cell, it is possible to use this as a power source for operating the illuminance meter and thereby possible to eliminate the power cable. Therefore, even if the illuminance meter is moved, it is possible to prevent obstacles to movement, breakage, etc. arising due to connection of the cable and possible to reliably measure the illuminance.
Further, to achieve the above object, the exposure apparatus of the present invention is provided with an illuminance measurement apparatus of the present invention.
According to the exposure apparatus of the present invention, since there is no trouble such as breakage of cables etc., the illuminance can be measured quickly in a predetermined time. Therefore, even when measuring the illuminance by interrupting the exposure processing by the exposure apparatus, it is possible to shorten the down time of the exposure processing as planned and in turn to improve the throughput (productivity) of the system as a whole.
To achieve the above object, the exposure apparatus of the present invention is an exposure apparatus for emitting a first beam for exposure on a mask and exposing a substrate through the mask by the first beam, provided with a photodetector provided on a movable member moving relatively with respect to the first beam or a second beam used for other than exposure of the substrate and wirelessly transmitting information obtain by receiving at least part of the first beam or the second beam and a receiver arranged separate from the movable member and receiving the information. In this case, the movable member can include a stage for holding the mask or the substrate. Further, the movable member can include a built-in storage device for storing energy to be supplied to the photodetector. In addition, further provision may be made of an energy generator for receiving at least one of the first and second beams and generating energy to be stored in the storage device.
To achieve the above object, another illuminance measurement apparatus of the present invention is an illuminance measurement apparatus provided with a holder type illuminance meter comprised of a dummy holder configured to be able to be attached to a substrate stage interchangeably
Nikon Corporation
Oliff & Berridg,e PLC
Smith Zander V.
Stock Gordon J
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