JPH084065B2 - Exposure equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention sets a minute distance between an original plate and an object to be processed placed on a fine movement stage to process a pattern provided on the original plate. The present invention relates to a so-called proximity type exposure apparatus that transfers and exposes an object. More specifically, the present invention relates to an exposure apparatus that automatically corrects the relative displacement between the original plate and the object to be processed, which is set before exposure, so as to keep it constant during exposure.

[Prior Art] As a conventional example of a proximity exposure apparatus,
FIG. 4 shows an and repeat type X-ray exposure apparatus.

In the figure, 1 is a gap sensor, 2 is a mask, 3
Is a mask stage, 4 is a wafer, 5 is a wafer stage,
6 is a piezoelectric element, 8 is an XY stage, 9 is a coarse movement stage, 10
Is a coarse movement stage driving device, 12 is a controller, 13 is a driver, 14 is an electron gun, and 15 is a target.

In this X-ray exposure apparatus, the gap sensor 1 measures the distance between the mask 2 and the wafer 4, and the measurement result is input to the controller 12, which in turn outputs a piezoelectric element via the driver 13 based on the input measurement result. The applied voltage of 6 is changed to drive the wafer stage 5 to set a predetermined gap between the mask 2 and the wafer 4. After that, the coarse movement stage drive device 10 moves the coarse movement stage 9 to the exposure area (two-dot chain line) to perform exposure.

[Problems to be Solved by the Invention] However, in this conventional example, the mask 2 is exposed during exposure.
The gap between wafer and wafer 4 cannot be monitored and
Even if the gap is set for each shot, the gap fluctuates due to vibration during movement to the exposure area and at stop, shock, or drift of the piezoelectric element during exposure, expansion and contraction due to changes in environmental conditions (temperature, humidity, etc.). In that case, it cannot be detected and corrected.

The present invention eliminates the above-mentioned drawbacks of the conventional example, and when the interval set between the original plate and the object to be processed changes during exposure, the change is detected and the fine movement stage is controlled so as to correct it. Thus, it is an object of the present invention to provide an exposure apparatus capable of performing precise transfer exposure by keeping the set interval constant from the end of the interval setting to the end of exposure.

[Means and Actions for Solving Problems] In order to achieve this object, the exposure apparatus of the present invention has a wafer stage (5) holding a wafer (4) and a wafer stage mounted on the wafer stage (5) for movement. XY stage (8) to align the mask with one of the divided areas of
And provided between the XY stage and the wafer stage,
Drive means (6) for minutely displacing the wafer stage in the Z direction orthogonal to the moving direction of the XY stage;
A mask stage (3), which is provided integrally with the moving surface of the stage and holds the mask, and an exposure means (14, 15) for exposing and transferring the pattern of the mask to the aligned region of the wafer are provided. An exposure apparatus for sequentially exposing and transferring a mask pattern onto a plurality of divided areas of a wafer, which is provided independently of the XY stage and which detects a gap between the mask and the wafer (1 ), A second sensor (7) which is integrally provided on the XY stage and detects the displacement of the wafer stage with respect to the XY stage in the Z direction, and one of the divided areas of the wafer on the XY stage. After aligning the mask and before the exposure transfer, the driving means is driven based on the output signal of the first sensor to set the distance between the mask and the wafer, and then the second transfer is performed during the exposure transfer. Of the sensor A controller (12) for controlling the XY stage and the driving means so that the driving means is driven based on an output signal to maintain a constant interval set before the exposure transfer. To do.

According to this, the interval between the mask and the wafer is set based on the output of the first sensor before the exposure, but during the exposure, this interval is held based on the output of the second sensor. Therefore, the drift of the piezoelectric element used in the driving means,
Variations in the spacing due to expansion and contraction due to environmental changes are eliminated, the spacing at the time of setting is maintained during exposure, and precise transfer exposure is performed. The second sensor XY stage is integrally provided, and even if the step movement is performed between the shot positions, the positional relationship between the distance measurement position by the second sensor and the driving means does not change, and Since the mask-wafer spacing is set again before the exposure, the mask-wafer spacing is controlled by always driving the driving means under the same conditions based on the output signal of the second sensor.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show an X-ray exposure apparatus according to an embodiment of the present invention. FIG. 1 shows the structure of an exposure apparatus and an exposure method. 1 is a first gap sensor, 2 is a mask, 3 is a mask stage, 4 is a wafer, 5 is a wafer stage, and 6 is a wafer stage.
Is a piezoelectric element, 7 is a second gap sensor, 8 is an XY stage, 9 is a coarse movement stage, 10 is a coarse movement stage driving device, 11
A sensor changeover switch, 12 is a controller, 13 is a driver, 14 is an electron gun, and 15 is a target. The apparatus shown in FIG. 10 is different from that shown in FIG. 4 in that a second gap sensor 7 and a sensor changeover switch 11 are added.

FIG. 2 shows the first and second gap sensors 1 of FIG.
It is a layout of (1A, 1B, 1C, 1D), 7 (7A, 7B, 7C). First
As the gap sensor, for example, a gap measuring device (Japanese Patent Laid-Open No. 61-223604) is used, and as the second gap sensor, a non-contact type minute displacement type is used.

In this embodiment, the exposure is performed by the step-and-repeat method, and the gap is set for each shot. In order to set a gap between the mask 2 and the wafer 4 in a certain shot, first, the first gap sensor 1
The gap between the mask 2 and the wafer 4 is measured by.
At this time, as shown in FIG. 2, the gap detection is performed by the first gap sensors 1A to 1D so that the gap in the exposure area (hatched portion)
Perform at any 3 of the points. The detected value is input to the controller 12, and based on this value, the controller 12
Drives the wafer stage 5 by changing the voltage applied to the piezoelectric element 6 (6A to 6C) via the driver 13 until the gap value reaches a predetermined value. After the gap setting is completed in this way, the sensor changeover switch 11 is switched to input the values detected by the second gap sensors 7A to 7C to the controller 12. These values are used as reference values Z _AO , Z _BO , Z _CO .

For exposure, thereafter, the coarse movement stage drive device 10 moves the coarse movement stage 9 to the exposure area (two-dot chain line portion), and X
Do by line. This and during exposure movement is always detected value of the second gap sensor 7A-7C Z _A to Z _C is the controller
Input to 12 and the deviation from the reference value ΔZ _A = Z _A −Z _AO , ΔZ _B −
Z _BO , ΔZ _C = Z _C −Z _CO is calculated. Then, the controller 12 changes the applied voltage to the piezoelectric elements 6A to 6C via the driver 13 so as to make this shift amount zero. As a result,
The gap set by the first gap sensor 1 described above is always kept constant until the end of exposure.

To perform the next shot, the coarse movement stage drive 10
The coarse movement stage 9 to the alignment area (solid line part)
After moving to the XY stage 8 and changing the exposure area, and again setting the gap with the first gap sensor 1,
Exposure is performed as described above. At this time, the second gap sensor 7 holds the gap in the same manner as described above. In addition, the second gap sensor 7
Since it is on the XY stage 8, even if the XY stage 8 is driven, the measurement position of the second gap sensor 7 and the positional relationship of the piezoelectric element 6 are the same. Therefore, the deviation amount ΔZ except the reference values Z _{a0 to} Z _c0 The calculation for driving the piezoelectric element 6 with respect to is always the same.

[Other Embodiments] FIG. 3 is a diagram showing an X-ray exposure apparatus according to another embodiment of the present invention. In the figure, 16 is an X-ray shutter, and the first gap sensor 1 can be moved by a driving means (not shown).

The gap setting and the reference value Z _o (Z _{A0 to} Z _c0 ) of the second gap sensor in this embodiment are exactly the same as those in the embodiment of FIG.

The exposure in this embodiment is performed by opening the X-ray shutter 16 after retracting the first gap sensor 1 out of the X-ray optical path by a driving unit (not shown). During exposure, the value Z (Z _{A to} Z _C ) detected by the second gap sensor 7 is constantly input to the controller 12 during the exposure, as in the embodiment of FIG. 1, and ΔZ = Z−
The wafer cage 5 is controlled so that Z _o becomes zero. Therefore, when the gap is set, the gap is
It is always kept constant.

EFFECTS OF THE INVENTION According to the present invention, the interval between the mask and the wafer, which is set based on the output of the first sensor before exposure, can be maintained based on the output of the second sensor even during exposure. . Therefore, it is possible to eliminate the drift of the piezoelectric element used for the interval setting means, the fluctuation of the interval due to the expansion and contraction due to the environmental change, and the interval at the time of setting can be maintained during the exposure to perform the precise transfer exposure. The second sensor is integrally provided on the stage, and even if the step movement is performed between the shot positions, the positional relationship between the distance measurement position by the second sensor and the distance holding means does not change. Two
Based on the output signal of the sensor, it is possible to control the gap between the mask and the wafer by always driving the gap holding means under the same condition.

[Brief description of drawings]

1 and 2 are views of an X-ray exposure apparatus according to an embodiment of the present invention, FIG. 3 is a view of an X-ray exposure apparatus according to another embodiment, and FIG. 4 is a conventional X-ray exposure apparatus. It is a figure which shows an exposure apparatus. 1: (first) gap sensor, 2: mask, 4: wafer, 5: wafer stage, 6: piezoelectric element, 7: second gap sensor, 11: sensor changeover switch, 12: controller, 13: driver.

Claims (1)

[Claims] 1. A wafer stage (5) for holding a wafer (4), and an XY stage (8) for mounting and moving the wafer stage to align one area in a divided area of the wafer with a mask. ) Is provided between the XY stage and the wafer stage.
Driving means (6) for minutely displacing the wafer stage in the Z direction orthogonal to the moving direction of the stage, and a mask stage (3) integrally provided on the moving surface of the XY stage and holding a mask And an exposure device (14, 15) for exposing and transferring the mask pattern to the aligned region of the wafer, and exposing and transferring the mask pattern to a plurality of divided regions of the wafer sequentially. A first sensor (1) that is provided independently of the XY stage and that detects the distance between the mask and the wafer; The second sensor (7) for detecting the displacement in the Z direction and the output signal of the first sensor after aligning one of the divided areas of the wafer with the mask on the XY stage and before the exposure transfer. Based by driving the drive means to set the spacing between the mask and the wafer, then during exposure transfer, the second
A controller (12) for controlling the XY stage and the driving means so that the driving means is driven based on the output signal of the sensor to maintain the interval set before the exposure transfer constant. An exposure apparatus.