JPH0529130B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stage error measuring device in a projection exposure apparatus.

[Conventional technology]

FIG. 3 shows an outline of the projection exposure apparatus. Light 2 from the mercury lamp 1 is condensed by a condenser lens 3, transmitted through a photomask 4, and then passed through a reduction lens 5 to project a reduced image of the photomask 4 onto a wafer 6 for exposure. Figure 4 shows an outline of the stage. The stage 10 has a V-shaped guide groove 11 at its lower part.
, and moves while engaging with the V guide 12.

On the other hand, the position of the stage is accurately measured by a laser length measuring device 7. The L-shaped mirror 8 is a reference mirror of the laser measuring device 7 and is fixed on the table 10. The L-shaped mirror 8 has a surface accuracy of λ/
It is an ultra-precision mirror machined to a size of 10 or less.

[Problem that the invention seeks to solve]

In the above apparatus, if the V guide 12 is processed correctly and straight, the projected image 20 is
Although the arrangement is correct as shown in FIG. 6 above, if the V guide 12 is not processed straight as shown in FIG. 5, the projected image 20 will be a disordered arrangement as shown in FIG. becomes. Manufacturing semiconductor devices generally requires multiple exposure steps.
Each process is not necessarily performed using the same model, but is often performed using multiple devices. In this case, since the yawing varies depending on the apparatus, it is clear that if exposure is carried out across a plurality of apparatuses, for example, when FIG. 6 and FIG. 7 are superimposed, correct superposition cannot be obtained.

Therefore, conventionally, in order to minimize yawing, it took a long time to manufacture the V guide 12, resulting in high costs. On the other hand, there is a limit to improving the straightness of the V guide, and the processing limit is about 1×10 ⁻⁶ red. Even if the surface is processed to this extent,
Overlay accuracy is worst for 150mm wafers
An error of 0.3 μm occurs. In ultra-large scale simulated integrated circuits, overlay accuracy of 0.1 μm or less is required, and the above error becomes an unacceptable value.

This type of apparatus is described in Japanese Patent Application Laid-open No. 173550/1982 or Japanese Patent Application Laid-Open No. 87330/1982.
However, all of these methods detect alignment marks on the wafer and adjust the deviation, and cannot be applied to wafers without alignment marks or to first-layer exposure.

An object of the present invention is to measure stage errors in a projection exposure apparatus that can perform accurate drawing even from the first layer exposure process and manufacture semiconductor devices with high precision without depending on the processing accuracy of the V guide 12. We are in the process of providing equipment.

[Means for solving problems]

In order to achieve such an objective, the stage error measuring device in the projection exposure apparatus of the present invention
and X-Y moving independently in the Y direction
In a projection exposure apparatus that places a semiconductor wafer on a stage and projects and exposes a photomask image onto the semiconductor wafer surface by step-and-repeat operation, a position measuring device that measures the position of the X-Y stage; The apparatus is characterized by comprising means for slightly rotating the photomask image based on the output from the device.

According to the above configuration, the yawing of the wafer stage can be measured and the photomask is rotated based on this position information, so that the wafer on the wafer stage can be allows photomask images to be drawn on the wafer in accurate alignment even if no alignment marks are drawn.

Furthermore, there is no need to detect alignment marks for each shot, and throughput can be greatly improved.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a stage error measuring device in a projection exposure apparatus according to the present invention will be described below with reference to FIGS. 1 and 2. The beam from the laser length measuring device 7 is split into both X and Y axes by a first beam splitter 31. The Y beam 32 divided in the Y-axis direction is divided into a distance measuring beam 34 and a yawing measuring beam 35 by a second beam 33. The distance measuring beam 34 and the yawing measuring beam 35 are each L.
incident on the character-shaped mirror 8, and the amount of movement of the stage 10 is determined by
It is now possible to measure with an accuracy of 0.01 μm. When the stage 10 moves accurately in the Y direction without yawing, the distance measuring beam 34
The amount of length measured by the yawing measurement beam 35 with respect to the amount of movement of the table is the same, and 2
There will be no difference between the two beams.

On the other hand, if the stage 10 moves while performing a yawing motion, a difference in length measurement will occur between the distance measurement beam 34 and the yawing measurement beam 35.

Assuming that the distance between the distance measuring beam 34 and the yawing measuring beam 35 is 50 mm, the measurement accuracy of the laser length measuring device is 0.01 μm as mentioned above, and when converted to angle, it is 2 × 10 ^-7 rad., which is extremely accurate. yaw can be measured.

When yawing occurs on the stage 10, rotated elements are transferred onto the wafer 6. To prevent this, just before exposure, the amount of yawing of the stage can be corrected by rotating the photomask by a corresponding angle.

The rotation of the photomask is as shown below. The photomask 4 is attached to a disk 37 having an opening 36.
Place it on top. The centers of the disk 37 and the photomask 36 are aligned. Further, the outer peripheral portion of the disk 37 is supported by three grooved rollers 38. One of the grooved rollers 38 rotates the disc 37 by a stepping motor 39. When yawing occurs in the stage 10, the yawing is measured by the laser length measuring device, and the stepping motor rotates according to this data. This operation is performed every time the stage 10 moves.

In the above explanation, the photomask rotates on the disk 37, but even if the photomask 4 is placed on the square table 40 and rotated about the fulcrum 41 as shown in FIG. The same correction as when placed on top is possible.

In the above explanation, the yawing of the stage was measured and corrected each time at the exposure point, but the invention is not limited to this, and since the amount of yawing of the stage 10 is reproducible at each position, this is not explained before. You can also measure this data and use this data to correct the photomask just before exposure.

[Effects of the Invention] As is clear from the above explanation, the stage error measuring device in a projection exposure apparatus according to the present invention can measure semiconductor elements with high precision without depending on the processing accuracy of the V guide of the X-Y stage. It can be manufactured with.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of a stage error correction device in a projection exposure apparatus according to the present invention, FIG. 2 is a block diagram showing another embodiment of the present invention, and FIG. 3 is a block diagram of a conventional projection exposure apparatus. Configuration diagram showing an example, No. 4
7 to 7 are diagrams for explaining parts that have not been taken into consideration in conventional devices. 1...Mercury lamp, 4...Photomask, 5...
Reduction lens, 6... Wafer, 7... Laser length measuring device, 10... Stage, 11... V-shaped guide groove, 12... V guide, 37... Disc, 39... Stepping motor, 40 ...A square table.

[Claims]

1. A reaction vessel, an anode forming a part of the reaction vessel, and an anode provided in the reaction vessel via an insulating member, forming a part of the reaction vessel, having an internal space and an opening, and communicating with the anode. a cavity-shaped cathode forming a discharge gap therebetween; a gas introduction pipe and a gas exhaust pipe respectively connected to the reaction vessel; means for supplying high-frequency power between the anode and the cathode; A dry etching apparatus comprising means for varying the internal volume and means for measuring the self-bias voltage on the cathode. 2. As a means for varying the internal volume of the cavity of the cathode, a metal bellows is provided in a part of the cathode, and a drive means for expanding and contracting the bellows part is provided in the upper part of the cathode. 1
The dry etching device described in Section 1. 3. A patent claim characterized in that, as means for varying the internal volume of the cavity of the cathode, a flat plate movable in the vertical direction is provided inside the cathode, and a driving means for moving the flat plate up and down is provided above the cathode. The dry etching apparatus according to item 1.