JPS58161321A - Projection type exposure device - Google Patents

Abstract

PURPOSE:To correct a reference position in case of revolution at theta deg. of a reticle automatically by detecting a reference mark on an X-Y stage, obtaining the quantity of revolution of the reticle through calculation from the waveform of the pattern and moving the quantity of revolution to a position reaching 0. CONSTITUTION:Beams from an illuminating light source 1 are condensed by a condenser lens 2, passed through the reticle 3 positioned by photoelectric microscopes 7A, 8B, reduced by a projection lens 4 and imaged onto a wafer 5. The wafer 5 is positioned onto a stage 6. The reference marks A, B are printed on the stage 6. A pattern detector 7 detects the reference marks through the projection lens. The X-Y stage is moved in parallel in the X or Y direction, and the reference mark B is pattern-detected and memorized similarly. An error DELTAtheta in case of the revolution of the reticle is calculated by two relative positional errors and the quantity of the X-Y stage moved. The reference positions of the photoelectric microscopes 7 are moved only by DELTAtheta.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a projection type exposure apparatus, and more particularly to an exposure apparatus that can automatically correct rotation of a reticle with respect to movement of an XY stage.

As shown in FIG. 1, a conventional projection type exposure apparatus condenses light from an illumination beam l with a condenser lens 2, transmits it through a reticle original screen 3 and a projection lens 4, and then
The reticle pattern is imaged onto the Ueno X5. Here, by moving the X-Y stage 6, the wafer 5 can be exposed with the same pattern on the wafer 5-F by step-and-IJ-1-.

In addition, the reticle original drawing 3 shows the 2
X-Y and θ positioning is performed by the photoelectric detectors 7 and 8, but the θ reference position is determined in advance by calculating the amount of rotation by arranging the wafers with no light at a specific pitch, and correcting the reference position. is being carried out.

However, when correcting this reference position, if the reference position is not accurate, or if the reference position fluctuates due to drift or gain changes of the photoelectric detectors 7 and 8, rotation errors occur for each chip. .

An object of the present invention is to provide an exposure apparatus that can automatically correct a reference position for θ rotation of a reticle.

In order to achieve this objective, the present invention provides two reference marks on the X-Y stage, moves the X-Y stage after aligning the reticle, and uses a through-the-lens method to set the reference marks. Detects the mark, calculates the amount of rotation of the reticle relative to the movement of the X-Y stage from the detected pattern waveform, moves the θ reference to the position where the amount of rotation is O, and executes realignment. This is how it was done.

The present invention will be described in detail below using Examples.

FIG. 2 is a block diagram showing an embodiment of a projection type exposure apparatus according to the present invention. Light from the illumination light source 1 is condensed by a condenser lens 2 to a photoelectron microscope 7A.

The image passes through the reticle 3 positioned by 7B, is further reduced in size by the projection lens 4, and is imaged onto the wafer 5. The wafer 5 is positioned on a stage 6, on which reference marks and (or ■') are marked.

Note that there is a pattern detector 7, and this pattern detector 7
The reference mark can be detected through a projection lens.

In such a configuration, after aligning the reticle, the reference mark ■ on the stage is moved below the projection lens as shown in FIG. 4, the pattern is detected by the pattern detector 7, and the relative position with respect to the reticle is sent to the CPU. Remember.

Next, the X-Y stage is moved in parallel in the X or Y direction, the pattern of another reference mark (2) or (2') on the stage is similarly detected, and the relative position with respect to the reticle is memorized. Here, the reference marks and ■ or ■' are adjusted in advance so that they are parallel to the movement of the stage.

Using these two relative position errors and the amount of movement of the XY stage, the rotation error Δθ of the reticle with respect to the stage is calculated. Next, the reference position of the photoelectric microscope 5 is moved by Δθ by the slit motor, and after the movement, alignment of the reticle is executed.

As a result, Δθ shown in FIG. 3 is automatically corrected, and
- Positioning of the reticle without rotational errors is performed with respect to the movement of the Y stage.

According to the present invention, even if the reference position changes due to gain fluctuations due to electrical drift of the photoelectron microscope or changes in the brightness of the illumination lamp, the wafer can be automatically rotated without having to expose it to light and check its alignment. Since the amount of eye difference can be detected and corrected, it has the effect of enabling self-check of the device.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a conventional projection exposure apparatus, Fig. 2 is a block diagram showing an embodiment of a projection exposure apparatus according to the present invention, and Fig. 3 is a block diagram showing an example of a projection exposure apparatus according to the present invention. FIG. 4 is a plan view of the reticle showing the reticle alignment position where the error occurred; FIG. It is.

Claims (1)

[Claims] 1. An exposure illumination system, a fine movement mechanism that moves the reticle original screen, a projection lens that projects the reticle original screen onto the wafer, and an X that moves the wafer using a step-and-repeat method.
- In a projection exposure apparatus consisting of a Y stage and a pattern detection system that detects a pattern through a projection lens,
- By setting two reference marks on the Y stage, moving the X-Y stage, and detecting the pattern of each reference mark through the projection lens, the origin position of the rotation of the reticle can be determined by moving the X-Y stage. A projection type exposure apparatus is characterized in that the rotation is automatically corrected so that the rotation becomes 0.