JPH02230714A - Parallelism adjusting system of original mask plate and substrate to be exposed - Google Patents

Abstract

PURPOSE:To perform accurate parallelism adjustments by utilizing a plane equation for a substrate to be exposed, and converting the height data of the substrate which are measured with optical measuring devices into the height data at the positions of tilt mechanisms by the operation of a microprocessor. CONSTITUTION:The following coordinates are set: the X-Y coordinates on the surface of a substrate to be exposed 4 with an arbitrary position as an original point; and the Z coordinate with a projected position 1a which forms a specified gap for an original mask plate as an original point. A plane equation zr=alphaxr+betayr+gamma which expresses the substrate is operated in a microprocessor based on the X-Y coordinate values (xr, yr) of optical measuring devices 3 provided at three points and the measured data zr of the height coordinate of the substrate 1. Thus the constants alpha, beta and gamma are computed. The data of alpha, beta and gamma and the X-Y coordinate values (xs, ys) of the tilt mechanisms 5 are imparted into the equation zs=alphaxs+betays+gamma. Thus the height coordinate value zs of the substrate 1 with respect to each tilt mechanism 5 is computed. The substrate 1 is moved in the vertical direction by the distance corresponding to the height coordinate value zs computed in each tilt mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a method for adjusting a mask original plate on which a wiring pattern is set and a substrate to be exposed to be parallel to each other in an exposure apparatus for semiconductor manufacturing. It is something.

[Prior Art] In the production of semiconductor ICs, a mask in which a circuit pattern is drawn on a transparent plate is used as an original plate, and the mask is optically projected onto a substrate to be exposed such as a wafer and copied.

Figure 3(a). (b) shows the main part of the exposure device, and (a)
is a vertical section. The mask original plate 1 is fixed to the optical unit 3 by a suitable support mechanism 2.

The optical unit 3 has optical measuring instruments A3a Ichiri+ 83a-2+ C3a- corresponding to three appropriate locations on the mask original plate 1.
3 is arranged. On the other hand, a substrate chuck stand 4a is provided below the mask original plate 1, and the substrate to be exposed 4 is chucked onto this stand. A tilt mechanism unit 5 is provided for the substrate chunk table 4a, and three tilt mechanisms D5a-1 and E5a-2+[i' 5a- are provided to press the substrate chuck table 4a.
Place 3. In projection exposure, it is necessary that the mask original plate 1 and the exposed substrate 4 be parallel to each other at the projection position where they are close to each other by a minute distance Δg.
A. B. The height position of the substrate is measured by C, and each tilt machine lateral D, E, F is operated by ril + constant data to move the substrate tilting machine 4a in the vertical force direction, and make both parallel at the projection position. It is.

[In the problem to be solved, when the three optical measurements nA, B, and C and the tilt mechanisms D, E, and F are installed at the same location, the measurement data of the optical measuring instrument Using as is,
By moving each tilt mechanism, both are made parallel. However, in reality, some of the three optical measuring instruments serve a purpose other than the above-mentioned height measurement, that is, the alignment of the mask original plate 1 and the exposed substrate 4. For example, as shown in FIG. 2B, the 41 holders 7AA and C are arranged in the center near both ends of the mask plate 1. In addition, the tilt mechanisms D, E, and F are used to suppress the substrate tilting table 4a in a well-balanced manner, for example, as shown in FIG.
b) are arranged as shown in FIG. For these reasons, the optical measuring instrument and the tilt mechanism are disposed at different positions, and therefore measurement data from the measuring instrument cannot be directly applied to the tilt mechanism. In the past, parallel adjustment was performed by ignoring the difference in grain, but recently, as both the mask original plate and the substrate to be exposed have become larger, and as circuit patterns have become smaller, projection accuracy has deteriorated and it has become difficult to achieve good results. There was a drawback that no copies were made. Therefore, it became necessary to perform some kind of correction or conversion on the measured data to accurately perform parallel adjustment.

This invention has been made in view of the above 212, and an object of the present invention is to provide a method for accurately performing parallel adjustment by calculating data on the movement distance of a tilt mechanism from measurement data by an optical measuring instrument. .

[Thousand Steps to Solve the Problems] This invention is arranged at three locations on a substrate to be exposed, which is placed under and facing a mask original plate on which a circuit pattern is set on a transparent plate. This is a parallel adjustment method between the mask original plate and the exposed substrate in an exposure apparatus that projects and exposes a circuit pattern by moving the substrate vertically using a horizontal tilt machine to make it parallel to the surface of the mask original plate. Set coordinates. 3 different parts of the tilt mechanism
The height data of the substrate determined by the optical measuring device installed at the location is calculated using the plane equation: z = αx + βy + γ (α, β, γ are constants)...
- According to (1), the height data of the substrate at the position of the tilt mechanism is converted, and the tilt mechanism is moved using the converted height data to make the substrate parallel to the mask original plate.

In the above, an XY coordinate whose origin is an arbitrary position on the surface of the substrate to be exposed, and a Z coordinate whose origin is a projection position that forms a certain gap with respect to the mask original plate are set. The XyPJA target value of the optical measuring device installed at three locations ( x r +
Y r) and measurement data zr of the measured height coordinates of the substrate
Therefore, the microprocessor generates a prison equation representing the substrate: zr=α)(r +βyr +γ (r is a parameter for the three optical measuring instruments)...
...(2) Calculate the constants α, β, and γ by performing calculations on
α, β, γ data and XY coordinate values of each tilt mechanism (x
s + V s ) as follows: zs=αXS+βys+
γ (S is a parameter for the tilt mechanism at three locations)...
...(3) Calculate the height coordinate value ZS of the substrate for each tilt mechanism by substituting 5. The height coordinate value Z calculated by each tilt mechanism
The substrate is moved downward by a distance corresponding to S.

[Operation] The principle of the parallel adjustment method according to the present invention will be explained with reference to FIG. In the figure, since the substrate 4 to be exposed is in the background, the height Z 15zp with respect to the XY coordinates (Xp.yp) of any point P on the surface L is determined by the plane equation: zp=αxp+βy
Represented by p+γ...(1').

Here, α and β are constants representing inclination angles of the plane with respect to the X1Y directions, respectively, and γ is a constant. The coordinate values of the optical measuring instrument (
x, V) and the measured height data Z to create a constant α,
β and γ are determined. Further, by substituting the data of α, β, and γ and the coordinate values of the tilt mechanism, the height data of the substrate at the position of the tilt mechanism can be changed.

Under the control of the microprocessor, the tilt mechanism is moved to make the substrate to be exposed parallel to the mask original plate.

Now, when formula (l') is applied, the origin of the XY coordinates may be arbitrary, but the projection position 1a that forms a certain gap with respect to the mask original plate is taken as the origin of the Z coordinate. This results in
The height coordinate value described below becomes a value for the projected position, which is convenient for control.

Add the XY coordinates (xr, Yr) of the three optical measuring instruments and the height measurement data zr to the plane equation (2) above to obtain the constants α, β, and γ, and the obtained α, β, and γ and the XY coordinates (X S +ys) of the three tilt mechanisms to the above equation (3) to determine the coordinate value ZS of the height of each tilt mechanism with respect to the substrate. When the substrate is moved downward by a distance corresponding to ZS by the tilt mechanism, the substrate stops at the projection position (z=0) and becomes parallel to the mask original plate.

[Example 2] Figures 2 (a), (b), and (c) show an example of the parallel adjustment force type for the mask original plate and the exposed substrate according to the present invention. Set the XY coordinates with an arbitrary point PO on the board 4 as the origin, and also
As shown in b), the Z coordinate is set with the projection position 1a forming a constant gap with respect to the mask original plate 1 as the origin. The center position of each of the three optical measurements 3A, B, C is pa
+ pb + p c, and the coordinates pa(x
a+ya) etc., the total is a1 in advance. Measured coordinate values and substrate height data Za measured by each optical measuring device
The constants α, β, and γ are calculated by substituting the above equation (2). α, β, γ and each tilt machine side D. E. Coordinates pd(xd, Y
By substituting d) etc. into the above equation (3), the height coordinate value zd etc. for the projected position of each tilt mechanism shown in Figure (C) are calculated. Each tilt mechanism moves the substrate chuck table 4a in one direction by a distance such as the calculated distance Zd, and the exposed substrate 4 is stopped at the projection position 1a, parallel to the mask plate 1.

Calculations for each equation (2) and (3) in below-1-,
Drive control of each tilt mechanism is all performed by a microprocessor, and detailed explanation will be omitted here.

[Effects of the Invention] As is clear from the above explanation, in the parallel adjustment method of the mask original plate and the exposed substrate according to the present invention, optical measurement is performed by using a plane equation for the exposed substrate and by arithmetic processing by a microprocessor. The height data of the substrate measured by the device is converted to the height data at the position of the tilt mechanism, and the tilt mechanism moves the exposed substrate so that it is parallel to the mask original plate at the projection position. The present invention can be applied to optical measuring instruments and tilt mechanisms disposed in semiconductor ICs, and greatly contributes to high-precision exposure devices such as semiconductor ICs.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the effect of the parallel adjustment method of the mask original plate and the exposed substrate according to the present invention, and FIGS. 2(a) and (b)
3(C) is an explanatory diagram of an embodiment of the parallel 114 alignment method of the mask original plate and the substrate to be exposed according to the present invention, and FIGS. 3(a) and 3(b) are the arrangement of the optical measuring device and the tilt mechanism in the exposure apparatus. and is an explanatory diagram of the operation. 1...Mask original plate, 1a...Projection position, 2
...Support mechanism, 3...Optical UniSoto, 3
a- 1... Optical measuring instrument A13a-2... Optical measuring instrument B13a-3... Optical measuring instrument C, 4... Substrate to be exposed, 4a... Substrate swing stand, 5... Tilt Unit, 5a-1...Tilt a structure 1), 5a-2
...Tilt mechanism E15a-3...Tilt machine side F0

Claims (2)

[Claims] (1) A substrate to be exposed is placed on the lower side facing a mask original plate on which a circuit pattern is set on a transparent plate, and the substrate is moved vertically using tilt mechanisms arranged at three locations. In an exposure apparatus that projects and exposes the circuit pattern parallel to the surface of the mask original plate,
The YZ coordinates are set, and the height data of the substrate measured by optical measuring instruments installed at three different locations than the three locations of the above-mentioned tilt mechanism is calculated using the plane equation: z = αx + βy + γ (α, β, γ are constants) ) is converted into height data of the substrate at the position of the tilt mechanism, and the tilt mechanism is moved based on the converted height data to make the substrate parallel to the mask original plate. A parallel adjustment method for the mask original plate and the exposed substrate. (2) In the above, an XY coordinate whose origin is an arbitrary position on the surface of the exposed substrate and a Z coordinate whose origin is a projection position that forms a certain gap with the mask original plate are set, and The XY coordinate values (xr,
yr) and measurement data zr of the height coordinates of the substrate measured by the optical measuring device, a microprocessor generates a plane equation representing the substrate: zr=αxr+βyr+γ (r is a parameter for the optical measuring device at three locations) The constants α, β, and γ are calculated by calculating the constants α, β, and γ.
, β, γ data and the XY coordinate values (x
s, ys) to the following formula: zs = αxs + βys + γ (s is a parameter for the three tilt mechanisms) to calculate the height coordinate value zs of the substrate in each of the above tilt mechanisms, and by each of the above tilt mechanisms, the calculation 2. A parallel adjustment method for a mask original plate and a substrate to be exposed according to claim 1, wherein the substrate is moved vertically by a distance corresponding to the height coordinate value zs.