JPS61251025A - Projection exposing apparatus - Google Patents

Abstract

PURPOSE:To simplify the structure for reducing the weight of movable parts during scanning process by a method wherein, when a negative shifting means and an exposed body shifting means are separately provided in a projection exposing apparatus optimum for a step and scanning operation to step-print a large picture for scanning said negative and exposed body, the shifting means is driven synchronously. CONSTITUTION:A holder 9 is fixed on a base 13 while the stroke of a mask stage 2 and a substrate stage 4 in Y direction is extended so that a mask and substrate 3 may be scanned on a projection optical system 5. A control circuit 15 is simultaneously controlling the movement of mask stage 2 and substrate stage 4 in Y direction during the scanning process is added to this unit. The control circuit 15 can make the stages 2 and 4 synchronize with each other for movement by means of controlling the pulse numbers and cycles of driving pulses to pulse motors 16 and 17 on the basis of data on stage positions from laser interferometers 18 and 19.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an exposure apparatus that prints a pattern image on an original plate, such as a semiconductor circuit, onto an exposed object, and particularly relates to an exposure apparatus that prints a pattern image on an original plate, such as a semiconductor circuit, onto an exposed object, and particularly relates to a step-and-scan (step-and-skip) exposure apparatus that prints a pattern image on an original plate, such as a semiconductor circuit, onto an exposed object. The present invention relates to a projection exposure apparatus suitable as a Yang type.

[Description of Prior Art] In a mirror projection type semiconductor printing apparatus, the entire screen is exposed by placing a mask and a substrate (or wafer) on a carriage and scanning the carrier onto an exposure surface.

However, as recent trends have shown that screens have become larger due to larger diameter wafers to reduce chip costs and the manufacture of large liquid crystal display panels for LCD TVs, the exposure range has become larger. In addition, there is a problem in that the apparatus becomes larger due to the need to increase the scan length.

As a countermeasure to this problem, a step-and-scan printing method has been considered in which the screen is divided and scan printing is performed multiple times.

FIG. 2 shows the configuration of such a step-and-scan type exposure apparatus previously proposed by the present inventors. In the figure, 1 is a photomask on which a printed pattern is formed, and 2 is a mask stage on which the mask 1 is mounted and is movable in the X, Y, and θ directions. 3 is a glass substrate on which a large number of pixels and switching transistors for controlling on/off of these pixels are formed by normal photolithography procedures in order to manufacture a liquid crystal display board, and the length of the diagonal line is is about 14 inches square. 4
is a substrate stage that can hold the substrate 3 and move in the X, Y, and θ directions. Reference numeral 5 denotes a well-known mirror projection system consisting of a combination of a concave mirror and a convex mirror, which projects the pattern image of the mask 1 aligned at a predetermined position by the mask stage 2 onto the substrate 3 at the same magnification. Reference numeral 6 denotes an illumination optical system that illuminates the mask 1 at the exposure position with light of a specific wavelength from a light source (not shown), and by exposing the photosensitive layer on the substrate 3 through the pattern on the mask, This is to enable the pattern to be transferred onto the substrate 3. Note that the optical axis of the projection system 5 is made to coincide with the optical axis of the illumination system 6.

7 is a LAB (linear air bearing) that can be moved along two guide rails 8 provided in the Y direction (perpendicular to the page), one of which is movable in the X direction (horizontal direction of the page) and Z direction (direction perpendicular to the page). The other type is a Z-direction restraint type. 9 is a holder (carriage) that holds the mask stage 2 and substrate stage 4 in a fixed relationship;
7, the mask 1 on the mask stage 2 and the substrate 3 on the substrate stage 4 can be integrally transferred.

Reference numeral 11 denotes a mask conveying device in which a plurality of masks 1 are set, and a desired mask is transferred to a substrate 3 by a holder 9.
The mask is transported to the mask stage 2 every time it is subjected to divided exposure.

Reference numeral 12 denotes a gap sensor for detecting the distance between the focal plane of the projection system 5 and the surface of the substrate 3, and is, for example, an air microsensor or a photoelectric type sensor that detects the distance using reflected light from the substrate 3. Reference numeral 13 denotes a base on which the projection system 5, illumination system 6, and guide rail 8 are mounted in a fixed relationship.

By the way, the apparatus shown in the figure includes a substrate stage 4 for moving the substrate 3 step by step, and a mask conveying device 11 for exchanging the mask 1 corresponding to each part of the substrate 3 to be printed.
The mask stage 2 and the like are mounted on the carriage 9, but in this case, the substrate stage 4 alone is 40K
1), and the load on the LAB 7 that levitates the carriage 9 with air becomes large, making smooth scanning difficult. Furthermore, the carriage is likely to have a flexible structure due to the demand for weight reduction, and the carriage 9 may be deformed by the weight of the substrate stage 4, etc., and the distance between the mask 1 and the substrate 3 and the mirror projection system 5 may change, resulting in defocusing. When the substrate stage 4 is moved to feed the substrate 3 step by step, a relative deviation occurs between the positioning reference of the mask 1 and the positioning reference of the substrate 3, resulting in steps, overlaps, or gaps between the separately baked batonins. There was an inconvenience.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems, and a first object of the present invention is to provide a step-and-scan type exposure apparatus with a simpler structure. A second purpose is to reduce the weight of the movable part during scanning to enable smoother scanning. Furthermore, the third objective is to maintain resolution and printing accuracy at a high level.

[Explanation of Examples] Hereinafter, the present invention will be explained in detail using the drawings.

Note that parts common or corresponding to those of the conventional example are represented by the same reference numerals.

FIG. 1 shows the configuration of a mirror projection exposure apparatus according to an embodiment of the present invention. In the same figure, Fig. 2 is the x
In contrast to the cross section taken along the 7 plane, the cross section taken along the YZ plane is shown. However, the Y direction is the scanning direction during printing, and the Z direction is the vertical direction.

The apparatus shown in FIG. 1 is different from the apparatus shown in FIG. A control circuit 15 extends to an extent that can scan the mask stage 2 and the substrate stage 4, and synchronously controls the amount of movement of the mask stage 2 and substrate stage 4 in the Y direction during scanning.
is added. In Figure 1, 16 and 1
7 are pulse motors 18 and 1 for moving the mask stage 2 and substrate stage 4 in the Y direction, respectively.
Reference numerals 9 denote length measuring devices, such as laser interferometers, for monitoring the positions of each stage 2.4, that is, the mask 1 and the substrate 3, respectively. Further, 51, 52, and 53 are a trapezoidal mirror, a convex mirror, and a concave mirror, respectively, which constitute the projection optical system 5.

In the above configuration, the control circuit 15 controls the number and cycle of drive pulses to the pulse motors 16 and 17 based on the stage position information from the laser interferometers 18 and 19 during scanning exposure. 4
move in sync with each other. As a method of this control, for example, the motor 16 is driven with pulses of a constant period to move the mask stage 2 at a constant speed, and the drive pulses are applied according to the positions of the stages 2 and 4 measured by the laser interferometers 18 and 19. The substrate stage 4 may be moved by supplying it to the motor 17.

In this case, the moving speeds of the stages 2 and 4 do not necessarily have to be the same, and may have an appropriate speed ratio. For example, simply by changing the output wavelengths of the laser interferometers 18 and 19, the stage 2.4 can be scanned at different speeds (velocity ratio -1). In addition, the control circuit 15 is further provided with means for varying the speed ratio,
The stages 2 and 4 may be driven at a speed ratio based on a command from a console keyboard (not shown) or the like. When the scanning speeds of the mask 1 and the substrate 3 are made different in this way, if the speed of the substrate 3 is made slower than the speed of the mask 1, the mask image is transferred onto the substrate 3 in a reduced size in the running direction (Y direction). . Furthermore, when the speed of the substrate 3 is increased, the mask image is enlarged and transferred onto the substrate 3 in the Y direction.

That is, a scanning type exposure device can be provided with an enlargement/reduction function, although only in one axis (Y) direction. If you utilize this function, especially the enlargement function, for example, the current step-and-scan method that divides the mask size into 4 vertically (Y) and horizontally (X) sections can be changed to 2 vertically scanned sections.
By doubling the size (substrate speed/mask speed = 2), it is sufficient to divide the same size mask into two in the vertical direction, reducing the number of substrate step movements and mask exchanges, and improving the throughput of the device. In addition to this, the time required to make masks can be reduced from four to two.

[Application Example of the Invention] In the above embodiment, the mask stage 2 and the substrate stage 4 are electrically synchronously controlled, but for example, the power of one motor is transferred to the gear 1. Each stage 2, through mechanical parts such as chains, belts, rods, cranks, levers, etc.
4, it is also possible to scan these stages 2.4 synchronously at the same speed or at different speeds.

[Effects of the Invention] As described above, according to the present invention, there is no need to run the holder (carriage) for holding the mask and substrate stage, and therefore the LA for floating the carriage is not required.
B becomes unnecessary, and the stage, motor, and control circuit for moving the mask and substrate, as well as the length measuring device for detecting the position of the mask and substrate, are originally used for aligning the mask and substrate. Since necessary components can be used as they are or with some modification, the configuration of the device can be simplified.

At the same time, the problem of the rigidity of the LAB air pad, particularly the problem of running instability due to lack of rigidity, is solved. Furthermore, since the holder can be fixed to a base, it can be constructed more firmly, and the relative positional accuracy and defocus between the mask and the substrate due to deformation of the holder can be reduced or prevented.

Furthermore, the traveling speed ratio between the mask and the substrate can be set arbitrarily, and therefore it is possible to realize an enlargement/reduction function that is not available in conventional scanning exposure apparatuses.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a semiconductor printing apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of a semiconductor printing apparatus according to an earlier application by the present inventors. 1: Photomask, 2: Mask stage, 3: Substrate, 4
: Substrate stage, 5: Mirror projection system, 9: Holder (carriage), 13: Base, 15: Control circuit, 16.17 Nibals motor, 18, 19: Laser interferometer.

Claims (1)

[Scope of Claims] 1. A projection exposure apparatus that transfers an image of an original plate onto an exposed object by scanning the original plate and the exposed object with a projection optical system in a state in which the original plate and the exposed object are aligned in position, Separately providing a means for transporting the original plate and a means for transporting the exposed object,
A projection exposure apparatus further comprising a drive means for driving the transport means synchronously when scanning the original plate and the object to be exposed. 2. The two transport means each include a first XY stage on which the original plate is mounted, a first motor that moves this stage in one axis direction that coincides with the scanning direction, and the object to be exposed. and a second motor that moves this stage in one axial direction that coincides with the scanning direction, and the driving means
and first and second length measuring means for detecting the position of the second XY stage, and a control circuit for electrically synchronously controlling the first and second motors based on the outputs of these length measuring means. A projection exposure apparatus according to claim 1. 3. Claim 1, wherein the driving means drives the two transport means at relatively different speeds during the scanning.
Or the projection exposure apparatus according to item 2. 4. The projection exposure apparatus according to claim 1 or 2, wherein the driving means includes means for adjusting or switching the speed ratio of the two transport means during the scanning.