JPS6328035A - Reduction stepper - Google Patents

Abstract

PURPOSE:To eliminate the gradation of a projecting image by individually independently moving upward or downward a plurality of substrate supporting pins provided in a region for supporting a semiconductor substrate. CONSTITUTION:A recess 6 is formed on the upper surface of a semiconductor substrate clamping jig body 5, a groove 7 for sucking in a vacuum the peripheral edge of a semicondnctor substrate 2 is formed on the peripheral edge of the recess 6, a plurality of substrate supporting pins 1, 1, ... are arranged in the recess 6, and the pins 1 are respectively connected to linear driving elements moving upward or downward individually independently. Further, a measuring instrument 4 for measuring the flatness of the substrate 1 supported by the pins 1, 1, ... and a controller 12 for regulating the height positions of the pins 1 by driving linear driving elements 3 by the output of the instrument 4 are provided. When the substrate 2 is placed on the body 5, the pins 1 are so moved by the elements 3 so that the substrate becomes the same plane.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a reduction projection exposure apparatus, particularly a reduction projection exposure apparatus equipped with a semiconductor substrate fixing jig that can measure the flatness of a semiconductor substrate surface and correct the flatness. Regarding.

[Prior Art] Conventionally, a jig for fixing a semiconductor substrate to the exposure stage of this type of reduction projection exposure apparatus has been designed to improve the processing accuracy of the jig surface that contacts the back surface of the semiconductor substrate and to increase the flatness of the jig surface. This increases the flatness of the semiconductor substrate surface.

[Problems to be Solved by the Invention] At present, efforts are being made to improve the resolution of reduction projection exposure apparatuses. If the resolution is improved, a problem arises in that the depth of focus of the reduction projection lens becomes shallower.

The conventional semiconductor substrate fixing jig described above cannot correct the flatness of the semiconductor substrate surface, so if the depth of focus of the reduction projection lens is shallow, the lens image plane may be tilted with respect to the semiconductor surface or the lens image plane may be curved. If the size of the wafer is too large, or the flatness of the fixture or wafer is poor, the semiconductor substrate surface will be out of the depth of focus range and the image will become blurry, resulting in the inability to obtain the desired resolution. .

A similar problem also occurs when foreign matter such as dust is caught between the semiconductor substrate and the fixing jig.

[Differences between the invention and the prior art] In contrast to the above-described conventional reduction projection exposure apparatus having a semiconductor substrate fixing jig, the present invention has an original content in a structure in which the flatness of a semiconductor substrate is corrected using a plurality of pins. .

[Means for Solving the Problems] The present invention provides a reduction projection exposure apparatus that performs exposure by aligning a semiconductor substrate coated with a photoresist with an exposure mask. A plurality of substrate supporting pins, a driving element that moves the pins up and down independently, a measuring device that measures the flatness of the semiconductor substrate supported by the pins, and a driving element using the output of the measuring device. The reduction projection exposure apparatus is characterized in that it has a control section that is driven to adjust the height position of each pin.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

(Example 1) As shown in FIG. 1, in this example 1, a recess 6 is provided on the upper surface of the semiconductor substrate fixing jig main body 5, and a groove 7 for vacuum suctioning the periphery of the semiconductor substrate 2 is provided at the periphery of the recess 6. A plurality of substrate support pins 1゜1... are arranged in the recess 6, and each pin 1
are connected to linear drive elements 3 that move up and down individually.

Furthermore, a measuring device 4 is provided to measure the flatness of the semiconductor substrate 2 supported by the pins 1, 1, . This device is equipped with a control section 12 that adjusts the .

In the embodiment, when the semiconductor substrate 2 is placed on the semiconductor substrate fixing jig main body 5, the recess 6 and the peripheral fixing @7 are evacuated and the semiconductor substrate 2 is attracted to the semiconductor substrate fixing jig 5. Next, the X-Y stage on which the semiconductor substrate fixing jig 5 is mounted moves, and the flatness measuring device 4 measures the flatness of the semiconductor substrate surface within the initial exposure range.
is moved by the linear drive element 3 so that the surface of the semiconductor substrate becomes flat. Further, the pin 1 moves so that the surface of the semiconductor substrate 2 is aligned with the inclination and curvature of the lens image plane, which have been determined in advance, to perform exposure. The X-Y stage moves to the next exposure position, and the sequence of performing the above operations and performing exposure is repeated to complete the exposure of one semiconductor substrate.

The manner in which the semiconductor substrate is corrected will be explained using FIGS. 2, 3, and 4.

FIG. 2 shows the semiconductor substrate 2 placed on the semiconductor substrate fixing jig 5 and vacuum-adsorbed. The surface of the semiconductor substrate 2 is not flat due to poor flatness or inclination of the semiconductor substrate 2, manufacturing errors or differences in height of each pin 1, and the like. The flatness of the surface of the semiconductor substrate 2 is measured by a flatness measuring device 4, and based on the results, each linear drive element 3 is moved according to a command from the control unit 12 so that the surface of the semiconductor substrate 2 becomes flat. Then, the state shown in FIG. 3 is reached. For example, from the state shown in FIG. 2, the linear drive elements 3a and 3b.

3d shrinks, and the element 3C shrinks a little, causing pin Ia.

1b, 1C, and ld decrease in accordance with the respective shrinkage amounts, and the surface of the semiconductor substrate 2 becomes flat as shown in FIG.

Thereafter, the linear drive elements 3a, 3b, and 3d extend to match the inclination and curvature of the lens image plane, which have been measured and determined in advance, in response to a command from the control unit 12, and the pin la,
1b and 1d rise, resulting in the state shown in FIG.

(Embodiment 2) FIG. 5 is a longitudinal sectional view of Embodiment 2 of the present invention, and FIG. 6 is a detailed view of the chuck 11 in FIG. 5. When the semiconductor substrate 2 is placed on the X-Y stage 10, the peripheral fixing groove 7
is evacuated and the semiconductor substrate 2 is fixed to the XY stage 10. The XY stage 10 is moved by the stage drive motor 8, and the semiconductor substrate 2 is moved to the exposure position. A recess 6 of the chuck 11 is fixed under the reduction projection lens 12 so as not to move relative to the reduction projection lens 12.
A vacuum is drawn, and the semiconductor substrate 2 is fixed to the chuck 11.

Next, the flatness of the semiconductor substrate surface within the exposure range is measured by the flatness measuring device 4, and based on the information, the linear drive element 3 and pin 1 are moved by commands from the control unit 12 to correct the semiconductor substrate surface. and the semiconductor substrate surface is a reduction projection lens 1
Add correction to match the inclination and curvature of the image plane in 3.
Apply exposure. Next, the vacuum in the recess 6 of the chuck 11 is released,
The X-Y stage 10 moves and the semiconductor substrate 2 moves to the next exposure position.

9 is a roller.

[Effects of the Invention] As explained above, the present invention corrects the surface of the semiconductor substrate, so that the lens image plane tilt and curvature of the reduction projection lens are reduced due to the narrowing of the depth of focus accompanying the increase in resolution of the reduction projection lens. In addition, due to the flatness of the semiconductor substrate, the flatness of the semiconductor substrate fixing jig, and the presence of dust between the semiconductor substrate and the semiconductor substrate fixing jig, the surface of the semiconductor substrate may deviate from the depth of focus range. This has the effect of eliminating the accompanying blurring of the projected image.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a semiconductor substrate fixing jig included in the reduction projection exposure apparatus of the present invention, and FIG. 2 is a diagram showing a semiconductor substrate placed on the semiconductor substrate fixing jig and vacuum suctioned.
Figure 3 shows the flatness of the semiconductor substrate surface measured and corrected to make it flat, and Figure 4 shows the semiconductor substrate surface roughly corrected to match the inclination and curvature of the lens image plane. FIG. 5 is a vertical sectional view of the second embodiment of the present invention, and FIG. 6 is a detailed view showing the chuck in FIG. 5. 1...Pin 2...Semiconductor substrate 3...
・Linear drive element 4...Flatness measuring device 5...Semiconductor substrate fixing jig body 6...Concavity 7...Peripheral fixing groove 8・
...Stage drive motor 9...Roller 10...X-Y stage 11...Chuck

Claims (1)

[Claims] (1) In a reduction projection exposure apparatus that performs exposure by aligning a semiconductor substrate coated with a photoresist with an exposure mask, a plurality of substrate support pins provided in an area supporting the semiconductor substrate and the pins are provided. a driving element that individually moves up and down the pins, a measuring device that measures the flatness of the semiconductor substrate supported by the pins, and a driving element that is driven by the output of the measuring device to measure the height position of each pin. 1. A reduction projection exposure apparatus, comprising: a control section for adjustment.