JPS6370420A - Semiconductor printing device - Google Patents

Abstract

PURPOSE:To enable a pattern to be printed With an optimum magnification of lens according to conditions of a wafer in each exposure process, by utilizing a mark alignment means for detecting expansion or shrink of the wafer and by correcting the magnification of a projection lens based on the detected result. CONSTITUTION:An alignment scope 23 reveals superposed images of a mask 1 and of a wafer 17. From these images, a deviation detector 20 calculates amounts of deviation in X-and Y-directions for alignment. Further, a distance between alignment marks provided at transversely opposite positions on a wafer is calculated from these deviations. A drive pressure supply source 8 for regulating a magnification of a projection lens is driven according to the data of expansion or shrink of the wafer so that the drive pressure supply source 8 drives a lens barrel 4b through a drive pressure tubing 7 to correct the magnification of the lens. Accordingly, an optimum lens magnification can be selected for printing each wafer according to expansion or shrink of the wafer caused variously in each exposure process and the pattern can be printed with high precision and high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a semiconductor printing apparatus for exposing and transferring a pattern of an original plate such as a mask onto an exposed object such as a semiconductor wafer in a semiconductor manufacturing process, and particularly relates to a semiconductor printing apparatus for exposing and transferring a pattern of an original plate such as a mask onto an exposed object such as a semiconductor wafer. The present invention relates to a projection exposure type semiconductor printing apparatus that performs pattern exposure through a system.

[Background of the Invention] In the semiconductor pattern transfer process, contact method,
The pattern of the mask is transferred onto the wafer by a printing device (exposure device) using an exposure method such as a proximity method, a reflective projection method, or a reduction projection method. In a projection exposure type printing apparatus, a mask pattern is printed on a wafer at the same size or reduced in size through an optical lens system. In such semiconductor printing equipment, the focus, magnification, etc. of the optical lens system must be set with high precision in order to successfully transfer fine patterns with high precision, and the alignment between the mask and the wafer must also be accurate. must be carried out.

[Prior Art] In a conventional semiconductor printing apparatus, a mark alignment means is used to perform positioning by measuring the amount of deviation of an alignment mark from a mask to a sea urchin. In this alignment method, as shown in FIG.
L, M, l.

WL and W are detected, the amount of deviation is calculated based on this, and the mask or wafer is driven in the X direction, the Y direction, and the θ direction (rotation direction) to perform alignment.

The deviation amounts of the left and right alignment marks on the mask and the sea urchin are respectively (ΔxL, ΔyL) and (ΔXR).

Δ3/R) (see Fig. 2(b)), then x, y.

The amount of drive in the θ direction is ΔX=(ΔxL+ΔXR)/2 ΔY=(ΔyL+Δy　R)　/2 It is given by Δθ=(ΔyR+Δy L)/L.

However, L is the distance between the left and right alignment marks.

In such an alignment method, when the wafer expands and contracts during each exposure process and the ratio of the mask to the wafer changes, alignment is performed so that the shot centers overlap.

However, even if alignment is performed by taking into account the expansion and contraction of the wafer using this method, if the amount of expansion and contraction of the wafer is large, the magnification of the optical lens system may not be appropriate, and printing performance may deteriorate. .

[Object of the Invention] The present invention has been made in view of the problems in the prior art described above, and the present invention detects the expansion and contraction of an exposed object, such as a wafer, using a mark alignment means for positioning, and It is an object of the present invention to provide a semiconductor printing apparatus that corrects the magnification of a projection lens by adjusting the magnification of the projection lens and makes it possible to print a pattern at an optimal lens magnification depending on the wafer condition for each exposure process.

[Example code] Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 3 shows the configuration of a projection exposure apparatus according to a 31st example of the present invention. In the figure, 1 is a mask on which a pattern to be transferred is drawn, 2 is a mask stage that holds the mask 1, and 3a, 3b, and 3c are glass members forming projection lenses. 4a.

4b and 4c are lens barrels that hold glass members 3a, 3b and 3c, respectively. Further, 5 is an air bearing guide that guides the lens barrel 4b, 6 is a static pressure pipe that applies static pressure to the air bearing guide 5, 7 is a driving pressure pipe that supplies pressure that drives the lens barrel 4b, and 8 is a driving pressure supply. Reference numeral 9 denotes a spring that supports the lens barrel 4b. 10 is a piezo element that drives the entire projection lens, 11 is a piezo element drive circuit, 12 is an air sensor nozzle that is fixed to the lower end of the projection lens and measures the distance from the wafer, 13 is a pneumatic pipe line for the near sensor, and 14 is the back of the air sensor. A converter that converts pressure into an electrical signal. Further, 15 is a projection lens surface plate that supports the projection lens;
6 is a support supporting the projection lens surface plate, 17 is a mask 1
18 is a wafer stage that supports the wafer and is capable of eight movements such as translation and rotation in a horizontal plane; 19 is a surface plate that is the basis of the entire apparatus. Furthermore, 20 is a deviation amount detector between the mask and wafer alignment marks, 2 is a computing unit, 22 is an illumination system that emits light for exposure, and 23 is an alignment scope that detects the relative deviation amount between the mask 1 and the wafer 17. be.

In a semiconductor printing apparatus having such a configuration, when aligning the mask and the wafer, first, as shown in FIG. 2(a).
As shown in FIG. 2, images of the mask and the wafer are superimposed and displayed on the alignment scope 23. From this image, the deviation amount detector 20 detects the left and right deviations in the X and Y directions (ΔxL, Δ
yL), (ΔxR.

Δy R') is calculated. Furthermore, using this value, the distance L between the left and right alignment marks WL and WR of the wafer is determined.
w is calculated from the following equation.

Lw= (LH+ΔxL−ΔXq 4 ΔyL
-ΔyRLM is the left and right alignment mark ML of the mask.

This is the distance between M8.

The ratio Δ of the distance between the mask and the wafer is ΔL=L,/
It is given by LM. If ΔL is not 1, it is considered that Lw has changed due to expansion and contraction of the wafer. In this case,
Based on this wafer expansion/contraction information, a driving pressure (atmospheric pressure) supply source 8 for adjusting the magnification of the projection lens is driven to drive the lens barrel 4b via the driving pressure conduit 7, thereby correcting the lens magnification.

By increasing the deviation amount detection position in the top, bottom, left and right of the alignment scope, -dimensional lens magnification correction can be made two-dimensional, increasing the detection accuracy of the deviation amount and performing highly reliable lens magnification correction. Can be done.

Furthermore, when detecting the amount of deviation, it is equally effective to use a method such as a laser scan or a slit scan instead of an image.

It is considered that expansion and contraction of the wafer occurs for each exposure process and does not occur for each exposure shot within the exposure process. Therefore, in order to improve throughput, it is desirable to perform this lens magnification correction only at the start of each exposure process.

[Effects of the Invention] As explained above, in the semiconductor printing apparatus according to the present invention, the amount of expansion and contraction of the object to be exposed such as a wafer is detected using the mark alignment means for positioning, and the projection lens is adjusted based on this. Magnification correction is being performed. Therefore, printing can be performed at an optimal lens magnification in response to the expansion and contraction of the wafer that occurs in each exposure process, and highly accurate and reliable pattern printing can be achieved.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the positions of alignment marks between the mask and the wafer, Fig. 2 is an explanatory diagram of the amount of misalignment between the mask and the wafer, and Fig. 3 is a configuration diagram of the projection exposure type semiconductor printing apparatus according to the present invention. It is. 1: Masks 3a, 3b, 3c: Projection lens component 7: Driving pressure conduit 8/driving pressure supply source 17° Wafer 18: Wafer stage Ml, MR, WL, Wn: Alignment mark patent applicant Canon Co., Ltd. agent Patent Attorney Tatsuo Ito Agent Patent Attorney Tetsuya Isuku Unihachi (a) (b) Figure 2 Figure 3

Claims (1)

[Claims] 1. A lens that projects the image of the original plate onto the exposed object, and a lens that detects alignment marks formed on the exposed object and measures the amount of deviation between the original plate and the exposed object. mark alignment means for relatively driving and positioning the original plate and the exposed object based on the exposure object, means for adjusting the projection magnification of the original image onto the exposed object, and a predetermined position of the alignment mark on the exposed object. 1. A semiconductor printing apparatus comprising: a control means for measuring the amount of deviation from the lens and driving the magnification adjustment means based on the amount of deviation to correct the magnification of the lens. 2. The semiconductor printing apparatus according to claim 1, wherein the mark alignment means detects marks at corresponding positions on each of the original plate and the object to be exposed, and measures the amount of deviation thereof. 3. The control means detects the amount of expansion and contraction of the exposed object from the measurement result of the amount of deviation by the mark alignment means, and performs the magnification correction so that the amount of expansion and contraction is minimized. Or the semiconductor printing apparatus according to item 2. 4. Claims 1 to 3, wherein the lens magnification correction operation is performed only once for each exposure process and not for each exposure shot within the exposure process.
The semiconductor printing apparatus according to any one of the preceding paragraphs. 5. The mark alignment means has an alignment scope that superimposes images of the original plate and the exposed object, and detects the amount of deviation between the original plate and the exposed object based on the image of the scope. The semiconductor printing apparatus according to any one of the ranges 1 to 4. 6. The lens magnification adjusting means includes a driving pressure conduit for applying pressure to and moving the lens barrel holding the lens, and a driving pressure supply source for supplying the pressure. The semiconductor printing apparatus according to any one of items 1 to 5.