JPS6231121A - Chuck for object to be exposed and reduction stepper using the same - Google Patents

Abstract

PURPOSE:To substantially deepen the depth of focus of a lens by providing a chuck for the object to be exposed with a correction plane, which consists of a curved plane matching the curve of an image projected by the projection system of exposure device. CONSTITUTION:An object to be exposed 2 is corrected by a chuck 3 and held with a holding section 6. The object to be exposed 2 is projected by a projection section 1 in the exposure device and projected at the focus positions 4 and 5 of the center of the image height and with the depth of focus. By correcting the object to be exposed 2 with the chuck 3 as shown in the figure, the image is focused at all the height of the image, resulting in the depth of focus being deepened. Moreover, the object to be exposed 2 is transferred to the specified position of exposure with the holding section 6 in order. When the exposure is made, with the plane corrected with the chuck 3, it is made possible to apply the correction chuck to the stepper system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention generally relates to an exposure apparatus for semiconductor printing, and more particularly to a correction chuck for an object to be exposed in an exposure apparatus for semiconductor printing.

[Prior Art] In the conventional lens design of exposure equipment for semiconductor printing, the exposure surface is made flat so that the best image can be obtained on that plane, and the chuck is designed to correct the exposed object to be as flat as possible. It was designed.

However, as the resolving power of exposure apparatuses has improved in recent years, the depth of focus that provides that resolving power has become shallower and shallower. Therefore, in order to obtain good resolving power over the entire exposed area, it is necessary to reduce the field curvature of the lens, and this is a major constraint in lens design.

[Problems to be Solved by the Invention and Means for Solving the Problems] An object of the present invention is to substantially increase the depth of focus of lenses currently available in semiconductor exposure equipment, and to solve constraints regarding field curvature in lens design. and this object is achieved according to the invention by a chuck for an exposed object comprising a correction surface consisting of a curved surface that corresponds to the curvature of the image plane projected by the projection system of the exposure device. .

[Example] FIG. 1 is a side view showing a state in which an example of the chuck for an exposed object of the present invention is used. FIG. 2 is a perspective view of a reduction projection type exposure apparatus equipped with a chuck for an exposed object according to the present invention, and shows a state of use similar to FIG. 1.

In these figures, 1 is a projection system portion of an exposure apparatus, 2 is an object to be exposed, and 3 is a chuck for correcting the object to be exposed. 4 represents a focus position at the center of a certain image height, and 5 represents a focus position at another image height. Reference numeral 6 denotes a holding section for the object to be exposed.

As shown in FIG. 1, the object to be exposed 2 is
By correcting as shown in the figure, the image will be in focus at all image heights. Moreover, as a result, the depth of focus also becomes deeper.

Although the chuck for an exposed object of the present invention can be applied to any type of semiconductor exposure apparatus, the case where it is applied to a reduction projection type exposure apparatus among semiconductor exposure apparatuses will be described in particular.

In that case, it is of course possible to process the correction surface of the chuck in consideration of the shot arrangement, but as shown in FIG.
It is convenient to move the object 2 to be exposed relative to the chuck 3 for each shot.

That is, as shown in FIG. 2, the object 2 to be exposed is sequentially moved to a predetermined exposure position by the holder 6, the flat surface is corrected by the chuck 3, and exposure is performed.

If correction can be performed for each shot in this way, the correction chuck can be easily applied to a single stepper type.

[Effects of the Invention] The effects of the chuck for an exposed object of the present invention are enumerated as follows.

1. Since field curvature is corrected, the effective depth of focus that can be used is increased.

2. When designing a lens, the tolerance for field curvature is increased, making the design easier.

3. Since the chuck part and the part for moving the exposed object are separated, the chuck can be easily applied to a stepper. □

[Brief explanation of the drawing]

FIG. 1 is a side view of relevant parts of a semiconductor exposure apparatus, showing a state in which an embodiment of the chuck for an exposed object of the present invention is used. FIG. 2 is a perspective view of the opening portion of a reduction projection type exposure apparatus equipped with a chuck for an exposed object according to the present invention. In the figure: 1: Projection system part of the exposure apparatus, 2: Object to be exposed, 3: Chuck, 6: Holder for the object to be exposed.

Claims (1)

[Scope of Claims] 1. A chuck for an exposed object, comprising a correction surface formed of a curved surface that matches the curvature of an image plane projected by a projection system of an exposure apparatus. 2. A chuck for an exposed object having a correction surface made of a curved surface that matches the curvature of an image plane projected by a projection system of an exposure device, and a means for moving the exposed object with respect to the chuck. A reduction projection type exposure device.