JPS6279621A - Projecting exposure equipment - Google Patents

Abstract

PURPOSE:To enable measurement of the distortion of an image easily and in high accuracy by comparing an X-Y stage controlled the position by a laser interferometer, the coordinates of a mark position detected on the X-Y stage and the theoretical value. CONSTITUTION:A mask 1 for measurement wherein a mark is formed at a definite pitch is projected on an X-Y stage 2 the position of which is controlled by a laser interferometer. Then, the mark is detected by moving the X-Y stage 2 from the reference point which is one point of the projected marks for detecting the mark with a sensor 3. The coordinates of the sensor 3 position are stored and sent to computing means. The coordinates of all the other mark positions are also stored with the same operations. The computing means compare the coordinates of the detected mark position and the coordinates of the position sent by pitch from the reference point and compute the distortion of an image. The obtained distortion of an image contains the error produced by the X-Y stage 2, etc. but these are removed by a statistical technique.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] This invention relates to a projection path light device capable of calculating volatile distortion.

[Conventional technology]

Conventionally, in a projection exposure apparatus,
[61] In J, a vernier pattern is woven on the wafer and the scratches are removed by one cutting, which is caused by magnification error, non-parallelism between the mask and the wafer, etc.
This method uses the non-near method or an electrical measurement method that measures the primary strain by measuring the sheet resistance after forming a special notch turn on the wafer by layering, development, and etching. (・TaO [Problem that Unimei is trying to solve]) The conventional image distortion measurement method mentioned above requires 5 steps of exposure and exposure 1* in the No. 27 method. However, the accuracy is poor due to visual inspection, and the electrical measurement method, which provides even higher accuracy, is not suitable for exposure.

The process of developing and etching is a membership fee, and in addition, there is a fee for a dedicated measuring device (There were 5 problems.0 This invention was made to solve these problems. The objective is to obtain a projection path light device that can be easily and accurately measured.

[Means for resolving problem Yw6] The projection m+ device according to this invention includes a measurement mask on which marks are formed at a predetermined pitch, and a sensor for outputting marks 'Ywl projected onto the mask. an X-Y stage whose position is controlled by an interferometer;
Mark position coordinates that can be detected on the Y stage and theoretical 1V
and calculating means for calculating the ripple distortion by comparing the ripple mark with

[Effect]

In this invention, the position coordinates of a mark projected on an X-Y stage having a sensor for detecting the projected mark are detected by the X-Y stage, and the detected position coordinates and the theoretical The values are compared and image distortion is calculated.

[Practical example]

FIG. 1 is a schematic diagram showing one embodiment of a projection exposure apparatus according to the present invention, in which 1 is a 611 mark on which marks are formed at a predetermined pitch.
1 constant mask, 2 position +1+ by V-the interferometer
1" X-Y stage, 3 is mouth i + gt x
- A sensor 4 is provided on the Y stage 2 to detect the mark projected from the measurement mask 1, and 4 is a reduction ratio of 1/
N1 is a small width lens, and 5 is a wafer GTII stand. The second figure is a top view showing the width of the measurement mask 1.
The marks are formed at pitches of ΔX and ΔY. below,
Let's talk directly about the operation.

First, a measurement mask I is projected onto the YX-Y stage 2. Next, one point among the projected marks is set as the 7 base point, and that value is U+￥'f! :X- to detect sensor 3
Move Y stage 2. Theoretically, for each mark of the same song at this reference point, the reduction ratio of the reduction lens 4 or 1/M
Therefore, 1/M ΔX interval and 1/M ΔYlv
It should be projected as l@. Therefore, in order to detect the mark by the sensor 3, the X-Y stage 2
is moved from the reference point at a pitch of 1/MΔX or 1/MΔY, for example, and when the mark cannot be detected by the sensor 3, image distortion has occurred, and the X-Y stage 2 detects it. Let Senna 3 #tai nearby and detect the mark. Then, sensor 3 when detecting the mark
The position coordinates of are stored and sent to calculation means (not shown). For other marks, TI is also pitched from the reference point! By performing the same operation using the f position as a reference, the position coordinates of all marks projected on the XY stage 2 are input to the tlL calculation means. Then, the calculation means compares the position coordinates of the detected mark with the position coordinates pitch-fed from the reference point and determines whether the image is distorted or not. calculate. The image distortion that was attended to in this way is caused by the g4
This includes differences, but these errors can be removed using a pile counting method.

Note that the image distortion obtained as described above may be taken into consideration to correct the positional deviation of the alignment mark caused by the image distortion.

[Effect of redundancy]

As explained above, this JAIIlH has a measurement mask on which marks are formed at a constant Dr pitch, and a sensor for detecting the marks projected on the upper surface of the measurement mask.
We are equipped with an X-Y stage whose position is controlled by an interferometer, and a calculation means that calculates the distortion by comparing the position coordinates of marks detected on this X-Y stage with theoretical values. Without using other measuring devices as a meal, we can easily
It also has the effect of being able to be measured in terms of crystallinity.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a projection exposure apparatus of the present invention, and FIG. 2 is a top view showing an example of a mask for measurement. In the figure, 1 is a mask for measurement, 2 is an X-Y stage, and 3 is a sensor. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] a measurement mask on which marks are formed at a predetermined pitch;
an X-Y stage that has a sensor for detecting a mark from the mask projected on its upper surface and whose position is controlled by a laser interferometer; and the position coordinates of the mark detected on this X-Y stage. 1. A projection exposure apparatus comprising: arithmetic means for calculating image distortion by comparing it with a theoretical value.