1. Field of the Invention
The present invention relates to carrier methods, exposure methods, carrier systems and exposure apparatuses, and device manufacturing methods, and more particularly to a carrier method in which a thin plate-shaped object is carried to a holding device, an exposure method which uses the carrier method, a carrier system which carries a thin plate-shaped object, and an exposure apparatus which is equipped with the carrier system, and a device manufacturing method using the exposure method and the exposure apparatus.
2. Description of the Background Art
Conventionally, in a lithography process for manufacturing electron devices (microdevices) such as semiconductor device (such as integrated circuits) and liquid crystal display devices, projection exposure apparatuses based on a step-and-repeat method (a so-called stepper), or projection exposure apparatuses based on a step-and-scan method (a so-called scanning stepper (also referred to as a scanner)) are mainly used.
Substrates such as a wafer, a glass plate or the like subject to exposure which are used in these types of exposure apparatuses are gradually (for example, in the case of a wafer, in every ten years) becoming larger. Although a 300-mm wafer which has a diameter of 300 mm is currently the mainstream, the coming of age of a 450 mm wafer which has a diameter of 450 mm looms near. When the transition to 450 mm wafers occurs, the number of dies (chips) output from a single wafer becomes double or more the number of chips from the current 300 mm wafer, which contributes to reducing the cost. In addition, it is expected that through efficient use of energy, water, and other resources, cost of all resource use will be reduced.
However, because the thickness of the wafer is not necessarily in proportion to the size of the wafer, the strength of a 450 mm wafer is much weaker than a 300 mm wafer. Accordingly, for example, as in the case of wafer carriage, employing a means similar to the current 300 mm wafer without any changes was considered to be insufficient. Therefore, the inventor previously made a proposal of a carrier method and the like which could be employed even in the case of a 450 mm wafer, in which the object was held in a non-contact manner from above by a carrier member, and was carried to a holding device (for example, refer to U.S. Patent Application Publication No. 2010/0297562).
However, according to further studies, in the case of using a Bernoulli chuck also disclosed in PTL 1 for holding the wafer in a non-contact manner, it became clear that even in the case of the current 300 mm wafer, positional deviation sometimes exceeded a permissible range at the time of carry-in of the wafer. Accordingly, in the 450 mm wafer, it can be expected that the positional deviation will become much larger, which makes alignment measurement (position measurement of marks on a wafer) performed later on more difficult.
Further, semiconductor devices are gradually becoming finer, therefore, high resolution is required in exposure apparatuses. As means for improving the resolution, shortening a wavelength of an exposure light, as well as increasing (a higher NA) a numerical aperture of a projection optical system can be considered. To increase the substantial numerical aperture of the projection optical system as much as possible, various proposals are made of a liquid immersion exposure apparatus that exposes a wafer via a projection optical system and liquid (for example, refer to U.S. Patent Application Publication No. 2008/0088843). In U.S. Patent Application Publication No. 2008/0088843, an exposure apparatus and an exposure method are disclosed whose main purpose is to perform a wafer alignment (mark detection) operation and a detection operation of surface position information (focus information) in a short period of time.
However, when the size of the wafer becomes 450 mm, a situation may be anticipated where throughput is not enough in the case when the exposure apparatus and the exposure method related to a conventional example disclosed in, for example, U.S. Patent Application Publication No. 2008/0088843, are employed without any changes, and an appearance of an exposure apparatus whose throughput can be further improved was expected.
USPTO Backgrounds
USPTO Backgrounds