JPH04148811A - Position detecting apparatus - Google Patents

Abstract

PURPOSE:To make it possible to detect the amount of position deviation in high accuracy by providing two alignment marks on a first object and a second object, and specifying the incident direction of luminous flux for alignment into the first object. CONSTITUTION:Luminous flux 7 is cast on an alignment mark 3. The diffracted light generated at this time is cast on an alignment mark 5. The center of gravity of the diffracted light from the mark 5 in the incident surface is detected with a detecting part 11 as the incident position of the luminous flux 7. Luminous flux 8 is cast on an alignment mark 4 by the same way. The diffracted light produced at this time is cast on an alignment mark 6. The center of gravity of the diffracted light from the mark 6 at the incident surface is detected with a detecting part 12 as the incident position of the luminous flux 8. At this time, the luminous flux 7 cast on the mark 3 and the luminous flux 8 cast on the mark 4 are cast on a reference plane T from the different directions at the slant angles. The positions with respect to the surfaces of objects 1 and 2 are determined by utilizing the position data from the detecting parts 11 and 12.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a position detection device, and is used, for example, in an exposure device for manufacturing semiconductor devices, to detect a first object surface of a mask, a reticule (hereinafter referred to as "mask j"), etc. When a fine electronic circuit pattern formed on a mask is transferred onto a second object surface such as a wafer by exposure, the amount of relative positional deviation between the mask and the wafer is determined and the positioning (alignment) of both is performed. The present invention relates to a suitable position detection device.

(Prior Art) Conventionally, in exposure equipment for manufacturing semiconductor devices, relative alignment between a mask and a wafer has been an important element for improving performance. In particular, in alignment in recent exposure equipment, for example, 117 alignment viscosity of submicron or less is being reduced due to the high integration of semiconductor devices.
There is a demand for something that does.

In many position detection devices, so-called alignment marks for alignment are provided on the mask and wafer surfaces, and a position +/l N that is 41t from these marks is used to
Alignment I is being performed on both sides. As an alignment method at this time, for example, the deviation jl between both alignment marks may be detected by performing image processing, or US Pat. No. 403,796! No. 1 and U.S. Patent No. 451
As proposed in No. 4858 and Japanese Unexamined Patent Publication No. 157033/1983, a zone plate is used as an alignment mark, and a beam of light is irradiated onto the zone plate. This is done by detecting the position of the focal point.

In general, alignment methods using zone plates are
Compared to the method using alignment marks (ii), this method has the advantage of being able to achieve relatively high precision alignment without being affected by defects in the alignment marks.

FIG. 6 is a schematic diagram of a conventional position detection device using a zone plate.

In the figure, the mask M is attached to the membrane 117 (=J
It is supported on the aligner main body 115 via a mask jack 116. Alignment spatulas 1 to 114 are arranged above the main body 115. In order to align the mask M and the wafer W, a mask alignment mark MM and a wafer alignment mark WM are printed on the mask M and the wafer W, respectively.

The light flux emitted from the light source 110 becomes \T'-line light by the projection lens system 111, passes through the half mirror 112,
The light is incident on the mask alignment mark MM. The mask alignment mark MM is composed of a transmission type zone plate, and the incident light beam is diffracted, and the +1st-order diffracted light is subjected to a convex lens action to converge on a point Q.

Further, the wafer alignment mark WM has the function of a convex mirror (divergent function) that reflects and diffracts the light condensed to the point Q by the reflective zone plate and forms an image on the detection surface 119.

At this time, the signal light beam that has undergone the 11th-order reflection and diffraction effect at the wafer alignment mark WM passes through the mask alignment mark MM as 0th-order light without being affected by a lens, and is focused on the detection surface 119F. It is something.

Here, the light beam undergoes an m-order diffraction effect at the alignment mark MM of the mask M, an n-order reflection diffraction effect at the alignment mark WM of the wafer W, and a second-order diffraction effect at the alignment mark MM of the mask M. Below, convenience 1
-) (m, n, n)-order light. Therefore, the luminous flux described by nη is (1, -1,.

0) becomes the signal light flux of the order light.

In the position detecting device shown in the figure, when the wafer W is misaligned by a predetermined amount relative to the mask M, the amount of light incident on the detection surface 119F increases with respect to the amount of misalignment ΔOW. The center of gravity (center of gravity) shifts. Whether the deviation of the detection surface 1191 at this time: 11ΔδW and the device deviation amount ΔaW have a fixed relationship, or by detecting the deviation amount ΔδW of the detection surface 1191 at this time, the relative relationship between the mask M and the wafer W can be determined. The amount of positional deviation ΔOW is being detected.

As shown in the figure, the distance from the condensing position Q of the light beam A J1 emitted from the mask M to the wafer 2 is aW, and the distance from the wafer W to the detection surface 119 is g b w, then the detection surface 1
The positional deviation amount ΔδW of 19F is as follows. As is clear from equation (a), the E7 displacement pupil is enlarged by (b w / a wl) times. This (bw/a w -1) becomes the positional deviation detection magnification.

In addition, in the apparatus shown in the figure, the incident position (reference position) of the signal beam is generally used as a reference when there is no positional deviation 11 between the mask and the wafer by performing a trial baking etc. after fixing the mask M, and this position is compared with the actual position. The detection surface 119 detects stars that are out of alignment with the incident position of the luminous flux.
Using the value ΔδW at this time, the positional deviation amount Δ0 is determined from equation 81.

(Problem to be Solved by the Invention) Generally, in the position detection device shown in FIG.
1.1) There are cases where the secondary light is almost condensed.

For example, after entering the alignment mark MM of the mask Ml-, it is transmitted as the 0th-order diffracted light, and is first reflected and diffracted by the 11th order at the mark WM to the alignment mark 1 of the wafer W1-, thereby producing the effect of concave power (divergence). Then, the convex power (
(0.-1.1) second brother or detection surface 1 affected by convergence)
In some cases, the light is almost focused on 19.

Figure 7 shows the (1, -1, 0) order light and (o, -i
, i) is an explanatory diagram schematically showing how the next light propagates.

Here, in general, (1,-1,O)-order light and (〇-1,1,
) The second brother differs in the detection magnification of the amount of movement of the incident position relative to the amount of relative positional deviation between the mask and the wafer. For this reason, the incident light beam (within the detection surfaces 11 and 9 at the j7 position, the position deviation of each point on the detection surface from that point by 1 her multiplied by the light intensity at that point) was integrated over the entire detection surface. The point where the integral value becomes 0 hex 1 ~ le (hereinafter referred to as the center of gravity (of the luminous flux))
When it is detected, it is affected by (o, -i, i) order light in addition to the (1, -1, 0) order light as the signal light flux, or the S/N ratio deteriorates ( Even if formula a) was used, there were cases in which the correct amount of positional deviation could not be detected.

If the light intensity ratio of the (i, -i, o) order light and the (0, -1,1) order light is always kept at a certain constant value, then the light on the detection surface formed by these two light beams is There is also a method of determining a detection magnification of the amount of deviation of the center of gravity position due to the entire intensity distribution with respect to the amount of relative positional deviation ΔσW between the mask and the wafer, and detecting the positional deviation using this as a new positional deviation detection magnification.

In this case, the light intensity ratio of each luminous flux may change due to wafer process factors such as variations in resist film thickness or variations in the position of the alignment objects in the direction perpendicular to the positional deviation detection direction. As a result, the total positional deviation detection magnification of the (1, -1, O)-order light and the (0, -1°1)-order light fluctuates, resulting in a positional deviation detection error.

In addition, edge scattered light (particularly zero-order reflected light components at edges) generated from alignment marks formed on the first object (mask) surface or edge portions of electronic circuit patterns may be applied to the detection surface. There was a problem in that it degraded the light/N ratio.

The present invention is directed to such a signal beam (m, n
, λ) becomes a detection error factor for the second brother (m', n'
, ! l') Effectively prevents the negative effects of secondary light (where m'≠m or n'≠n or υ'≠f/) and edge scattered light.
The object of the present invention is to provide a position detection device capable of detecting misaligned inkstones with high precision.

(Means for Solving the Problems) The position detection device of the present invention has a first object and a second object arranged facing each other.
two alignment marks A1 that perform a wavefront conversion action on the first object surface when detecting a relative positional deviation with the object;
A2 is provided, and two alignment marks B1. B2 is provided, and the light beam from the light projecting means is directed obliquely onto the first object surface from one side with a reference plane formed by the normal to the first object and a direction orthogonal to the positional deviation detection direction as the boundary. The first light beam is made incident and subjected to wavefront conversion by the alignment mark A1 and the alignment mark B1, respectively, and the light beam from the light projecting means is combined into one J, C quasi-.P
A further 1 beam is incident on the first object surface from the other side with the surface as a boundary,
The alignment mark A2 and the alignment mark B2
The second light beams each subjected to a wavefront conversion effect are guided onto a predetermined surface, the incident positions of the first light beam and the second light beam on the predetermined surface are detected by a detection means, and the light beams from the detection means are detected. The present invention is characterized in that a relative positional shift between the first object and the second object is detected using the output signal.

In particular, in the present invention, the two alignment marks A1 and A2 on the first object plane are formed separated by a predetermined distance in the positional deviation detection direction, and the two alignment marks A1,
The angle of incidence of the light flux from the first stage of light projection that enters A2 is +l゛ reflected light from each alignment mark -1.
The first object surface is set so as not to intersect with the force after ejection, and the first object surface is set so as not to intersect with the force after the first object surface is ejected. The second luminous flux is ])0
The direction of incidence and angle of incidence of the two light beams are such that the projection loci of the optical path of the first light beam and the optical path of the second light beam on the first object plane intersect with each other under the imaging action of the alignment mark; The fact that the pattern shape, arrangement, etc. of each alignment mark is fixed is taken as f, li sign. When a first object and a second object are separated, alignment marks A1 and A2 for the first and second signals, which function as physical light elements, are formed on the object plane A, and the alignment marks A1 and A2 are formed on the object plane B.
Similarly, alignment marks 81 and B2 for the first and second signals having the function of a physical optical element R- are formed, and a light beam is made incident on the alignment mark A1,
The diffracted light generated at this time is made incident on the alignment mark B1, and the center of gravity of the light beam within the incident plane of the diffracted light from the alignment mark B1 is detected by the first detection section as the incident position of the first signal light beam.

Here, the center of gravity of the light flux is the point at which the integral value becomes 0 vector when the position vector of each light-receiving point from that point is multiplied by the light intensity of that point over the entire surface of the light-receiving surface. Alternatively, for convenience, the point at which the light intensity is at its peak may be used as the center of gravity of the I-luminous flux. Similarly, a light flux is applied to the alignment mark A2, and the diffracted light generated at this time is made to enter the alignment mark B2, and the light flux change point on the incident surface of the diffracted light from the alignment mark B2 is set as the incident position of the second signal light flux to the second detection unit. Detected by

At this time, the first signal light flux to be incident on the alignment mark A1 and the second signal light flux to be incident on the alignment mark A2 are respectively directed to the reference plane formed by the first object surface normal and the direction perpendicular to the positional deviation detection direction. The light is incident obliquely from different directions.

Then, the object plane A and the object plane B are positioned using the two position information from the first and second detection sections. At this time(
For m, n, n)-order light, (m',
Each element is set so as to reduce the influence of (n', u') order light and edge scattered light.

In addition, in the present invention, the IR center of gravity of the light beam incident on the first detection section and the center of gravity of the light beam incident on the second detection section are displaced in the opposite direction with respect to the device misalignment between object plane A and object plane B. Each alignment mark A, 1. A2. B1. B2
is set.

(Embodiment) FIG. 1 is a perspective view of a main part of a first embodiment of the present invention, FIG. 2 is an xz blood cut diagram of FIG. 1, and FIG. 3 is an xy sectional view of FIG. 1.

In the figure, 1 is the first object corresponding to object plane A, and 2 is object plane B.
This is a second object corresponding to , and the case where the relative positional deviation amount in the X direction between the first object 1 and the second object 2 is detected is shown. 5 is an alignment mark provided on the first object 1, and 3 is an alignment mark provided on the second object 2, for obtaining the first signal light. Similarly, 6 is an alignment mark provided on the first object 1, and 4 is an alignment mark provided on the second object 2, for obtaining the second signal light.

Note that the two alignment marks 5 and 6 on the first surface of the first object
If the distance is 1il1 in the positional deviation detection direction (X direction),
1 and placed.

Marks 3, 4, 5.6 for each Aryran 1 are 1-dimensional or 2-dimensional
It consists of an optical member that performs a wavefront conversion function, such as a physical optical element Y' such as a grating lens or a diffraction grating that does not have a lens function. 9 is a wafer scribe line, 10 is a mask scribe line,
On that 1, a mark has been formed. 7.8 is the first alignment for the first and second alignment described in 11η. 2A No. 5 light east (hereinafter also referred to as t'"first and second light beams") is shown.

The first light beam 7 and the second light beam 8 are relative to the reference plane T formed in the direction (X direction) perpendicular to the normal to the first object surface and the positional deviation detection direction (X direction). Each beam is incident obliquely from a different side. In the figure, the light is obliquely incident from a substantially symmetrical direction with respect to the reference plane T.

Let 7' and 8' (not shown) be diffracted light beams of predetermined orders corresponding to the aforementioned first and second signal light beams 7.8 and 11:m<difference.

In this embodiment, each luminous flux is expressed using the method defined in 110- above, and the 1st 11th luminous flux 7 is (1, -1, O)-order light, and the 2nd - 11th luminous flux 8 is (-1, 1, , O) order light, luminous flux 7' is (0
, -1, 1st order light, and the light flux 8' is (0°1, -1) order light.

1.1. ．． Reference numerals 12 denote first and second detection units for detecting the first and second Buddhist light beams 7 and 8, respectively.

1st. The second detection unit 11.12 is composed of, for example, a one-dimensional CCD, and the arrangement direction of the element r- is xIl! It is heading in the I11 direction.

For convenience of explanation, the optical distance from the second object 2 to the first or second detection unit 11.12 will be referred to as LL. The distance ml between the object 1 and the second object 2 is g, the focus 5ψ of the alignment masks 5 and 6,
Let the distances be respectively f +, 1. Let f a2 be the first object 1
Let Δσ be the relative positional deviation of the second object 2 and the second object 2, and the first object 2 at that time. The displacement amounts of the first and second signal light beam centers of the second detection unit 11.12 from the coincident state are defined as Sl and S2, respectively. Note that the alignment light beam incident on the first object is assumed to be a plane wave for convenience, and the symbols are as shown in the figure.

The displacement stars S and S of the light flux of No. 8 Tunshin are the focal points F, , F2 of alignment marks 5 and 6, and alignment mark 3.
, 4 connecting the optical axis centers of 1j5ALIL2 and the detection unit 1
It is determined geometrically as the intersection with the light-receiving surfaces of 1 and 12. Therefore, in order to obtain the displacements as+ and S2 of the center of gravity of each signal beam in opposite directions with respect to the relative positional deviation between the first object 1 and the second object 2, the signs of the optical imaging magnifications of the alignment marks 3.4 are set to match each other. This is achieved by doing the opposite.

In this example, the types of light sources include semiconductor lasers, 1(5, -Ne lasers, A, lasers, and other light sources that emit coherent light fluxes, and light sources that emit non-coherent light fluxes such as light emitting titers. etc. are used.

In this example, as shown in FIG.
are incident on the alignment marks 5 and 6 on the first side of the mask at a predetermined angle, are transmitted and diffracted, and are further reflected and diffracted by the alignment marks 3.4 on the second side of the wafer, and are detected by the detection unit 1.1.
．． 12.

Next, a light projecting optical system for irradiating the alignment marks 5 and 6 of the first object 1- with light beams from different directions will be described with reference to FIG.

Figure 3 shows light sources 3a, 3c+ and projection optical system, 30.31
, an alignment pickup head 36 containing a mirror 34.35 and a light receiving optical system 32.33 in one housing, and an alignment mark 3.4. ．． 5.6 and 1st. FIG. 7 is a schematic diagram of the main part of the second light beam 7.8 viewed from the top.

1st A1: A beam of sunlight 7 emits light from a light source 38, passes through a projection optical system 30 and a mirror 34, and irradiates the alignment mark 5 on the surface of the first object 1 at a predetermined angle. Similarly, the second (
The Jj light beam 8 is emitted from the light source 39, and is irradiated by the projection optical system 31 and the mirror 35 onto the alignment mark 6 of the first object 1-I- at a predetermined angle. Here is the first thing. 2nd child bundle 7
, a (7) 1H<j The angle of incidence is set so that the specularly reflected light on each first object surface intersects P so as not to intersect too much before entering the first object surface. .

By doing this, multiple positional deviation signal lights (for example, (1, -1, 0
) Arrangement of alignment marks to avoid deterioration in positional deviation measurement accuracy caused by the (0, -1, 1) order diffracted light and the (0, -1, 1) order diffracted light as the light beam 7' reaching the first detection unit 11 surface. The size of the alignment mark, etc. can be set relatively easily. Further, edge scattered light from the edges of the circuit pattern along the X direction is prevented from reaching the first detection unit 11 surface F by appropriately setting the incident angle.

Next, these avoidance conditions will be explained based on FIG. 2.

The problem of unnecessary diffracted light that has been a problem in the past, that is, the (1, -1, 0) order light 7 as the signal light and the (0, -
1,1) Regarding the simultaneous occurrence of the order light 7', in this example, (
It is assumed that only the 1st, -1st, O) order light is received as signal light. Therefore, the first. Incident angle of second signal beam 7.8 on first object 1 surface and alignment marks 3, 4, 5
．． The conditions for the arrangement of 6 in the X direction are gt a nφ 〉!・・・・・・・・・
(1) becomes.

Here g is the first. The distance between the second objects (in the X direction), φ is the angle of incidence of each signal beam on the xz plane, which is 1.1 with respect to the normal to the first object surface, and the vertical axis is the first object of each alignment mark. −X direction on the object (boundary point in the +xX direction and +XX on the second object
- X direction) distance from the boundary point (see Figure 2)
represents. (The part in parentheses corresponds to the alignment mark for the first signal beam 7) Also, as an avoidance condition to prevent the edge scattered light of the pattern from entering the detection section, ZSLanφ2+xs2>xsM......(2
) and ZSl, an φ, + xs, > −xsM
”-...i3).

Here φ1. φ1 is the angle between the principal ray of the incident light beam in the xz plane and the normal to the first object surface, ZS is the distance xs in the X direction between the first object 1 surface and the detection unit 11 (12), and xs2 is the The center positions of flymen 1 to marks 5 and 6 of one object blood in the X direction, and ±xsM are the end values of the light receiving area of the detection unit in the X direction.

In this embodiment, the first . Incidence conditions for the second beam, arrangement of alignment marks, size of alignment 1-mark,
and 1st. By appropriately designing the imaging conditions of the second light beam 7.8, it is possible to simultaneously avoid unnecessary diffracted light 7', 8' and edge scattered light.

Further, in this embodiment, the first . By adopting a method in which the second light beams 7 and 8 are incident on the first object plane and the entire optical path system including the exit light beam is configured approximately symmetrically, the first. Changes in the position of incidence of the light beam on the detection unit due to factors such as the relative inclination and relative spacing between the second object plane and the like are determined in the first step. It is set so that it can be canceled relatively between the second beams.

Furthermore, the distance between the alignment marks 3.4 on the second object plane (measured value in the X direction) is shortened compared to the distance between the alignment marks 5.6 on the first object plane (measured value in the X direction). As a result, the local waviness of the second object surface,
It is constructed in such a way that it is not easily affected by distortion or the like.

Next, a description will be given of the projection angle of the light beam projected onto the alignment mark with respect to the commercial normal line of the alignment mark, and the incident position of the light beam on the detection unit surface corresponding to the amount of positional deviation between the first and second objects.

The alignment marks 3, 4, and 5.6 are each composed of a crating lens, and each of the alignment marks 3, 4, and 5.
, 4, 5.6. Also, crating lenses 5, 3
, 6.4 focal lengths f, , 2nd . f', 1. Fourth
shall be.

Now, the center position (optical axis position) of the crating lens 5 (+) on the first object plane is (XMOI, :)'MOI
+ O), and the imaging point position of the parallel light beam incident on the crating lens 5 at an angle θ in the XZ plane is (XMI+yi
i++ ZMI), then ZMl=-f I .

On the other hand, the center position (optical axis position) when the misaligned star of the crating lens 3 on the second object is zero is (Xw+, y
w+, g), and the crating lens 3 is (X
M1, :xMi, fMn) When Hl is zero (X sI+ ySl, Z s+
). Similarly, the first object 1
The center position (optical axis position) of the crating lens 6 is (
XMO2+ yiio2. O), and similarly to the crating lens 5, the imaging point position is (X M2yv2.
fs). Also, the center position (optical axis position) when the positional deviation amount of the crating lens 4 is zero is (XW2+
yw2. g) The grating lens 4 is (X
M21 XM2. When the positional shift amount of the point light source at f: + is zero (X S2+ '/S2.2 g
Assume that the image is formed at the position 2).

Based on the above parameter settings, the first light beam 7 is formed (
Let S11 be the change in the light intensity center position of the first detection unit 11 -1- corresponding to the positional deviation amount Δσ of the second object with respect to the first object of the i, -i, o)-order light.

Similarly, let S12 be the change in the light intensity gravity center position of the detection unit 12 of the (-1, 1°0) order light forming the second light beam 8.

Furthermore, from the general relationship of lens imaging characteristics, XMOi ”
xMi” f2+-1tanθ, (i=32)
``(8) Also, XM i + X W i is the amount determined by the deflection angle of the principal ray of the crating lens on the first object plane and the crating lens on the second object plane, respectively, and the focal length of each. ζ3-θ-φJ (j=t, 4) is the deflection angle of each alignment mark with respect to the incident angle θ.

Now, the origin is the center of the alignment mark setting area on the first object plane, the detection direction of the amount of positional deviation in the alignment mark plane is the X axis, the orthogonal direction is the y axis, and the normal direction of the alignment mark plane is the Z axis. Take the axis. Also θ1--
02, and the luminous flux is symmetrically entered.

The detection unit is 1-xyz orthogonal off-shore reference system, and the center of the light receiving area is represented by (o, ys, Zs), and the light receiving area is rectangular and its size is dl in the X direction and d2 in the orthogonal direction.
shall be.

Now, at the (1,, -1,0) next light, 1''shi, (4),
Substituting equation (6) into equation (5), the first result. Second luminous flux 7.8
The change in the light amount and center of gravity position S ll+ 312 is +XM, respectively.
(II −fl tanθ+ --
--(4)′”XMO2” fy tanθ+
”(5)′.

Here, the coordinate origin on the X-axis is set at the midpoint between the alignment marks 5 and 6 on the first object plane (the center on the line segment connecting the centers of each alignment mark).

FIG. 4 is a schematic diagram of the main parts of the second embodiment of the present invention, and FIG.
This corresponds to the xz sectional view in the figure.

In this embodiment, two alignment marks 3.4 provided on the surface of the second object 2 are provided overlappingly in the middle region. The other configuration is similar to the first embodiment shown in FIG. 1 and is substantially concave.

In this embodiment, by providing the two alignment marks 3.4 overlappingly in a single area of the second object 2, the alignment marks 3.4 are arranged in a single area, so that the alignment marks 3.4 are arranged in an area where the alignment marks 3.4 are arranged. 1゜Second detection section''-first. This avoids a situation in which the relative distance in the X direction between the second light beams 7 and 8 changes from the design value.

In addition, the same effects as shown in the first embodiment can also be obtained in this embodiment. The optical path Proposition 1 of the second luminous flux 7.8 is (+), (
2), I by performing appropriately based on formula (3)
Mr. F'J can achieve this.

In the second embodiment, the first and second nine bundles 7 ejected from the second surface of the second object
.

According to the results of simulations conducted by the present inventors based on a number of ray tracings, when such intersecting optical paths are used, the first. The first. The first on the second detection part surface. Fluctuations in the relative distance between the second light beams 7°8, ie, occurrence of positional deviation measurement errors can be suppressed favorably.

FIG. 5(A) shows a configuration diagram of the peripheral portion of the apparatus when the first embodiment of FIG. 1 is applied to a proximity type "f" conductor manufacturing apparatus. Elements not shown in FIG. 2. As a light source 13, collimator lens system (or beam diameter conversion lens) 14, projection light beam bending mirror 15, pickup housing (alignment head housing) 16, wafer stage 17, positional deviation (r3 processing unit 1B, wafer stage drive These are the control unit 19, etc. E indicates the width of the exposure light beam.

Also in this example, the first object, the mask in 1)] and the second object
The detection j11 of the amount of relative positional deviation of the wafer 2 as an object is performed in the same manner as explained in the first practical example.

In this embodiment, for example, the following method can be adopted as a procedure for performing i7 device integration.

The first method is the detection surface 11a of the detection unit 11.12 for the amount of positional deviation Δσ between the two objects.

12b is obtained, and the signal processing unit 18 calculates the positional deviation (1 knee Δ0) between both objects from the +li center deviation No. 121, and calculates the positional deviation amount Δ0 at that time.
The stage drive control unit 19 moves the wafer steak chef by an amount corresponding to 0.

As a second method, the signal processing unit 18 determines the direction in which the positional deviation amount Δ0 is canceled from the No. 13 from the detection unit 11.12, and the stage drive control unit 19 moves the wafer stage 17 in that direction to correct the positional deviation amount Repeat this until Δσ is within the allowable range.

Flowcharts 1 to 117 of the following 1-1 alignment procedure are shown in FIGS. 5(B) and 5(C), respectively.

In this embodiment, as can be seen from FIG. 5(A), the light beam from the light source 13 is directed from the outside of the exposure light beam to the alignment mark 5.
The position of the incident light beam is detected by detecting the diffracted light incident on the exposure light beam 6 and emitted from the alignment mark 3.4 to the outside of the exposure light beam by detection units 1.1 and 12 provided outside the exposure light beam.

With such a configuration, it is possible to realize a system in which the pickup housing 16 does not require a retracting operation during exposure.

<Effects of the Invention> According to the present invention, when detecting the relative positional deviation between the first object and the second object, the conditions of the above-mentioned expressions < (+), (2), and (3) are satisfied. By setting the incident angle and direction of the two light beams for alignment onto the first object plane, and the arrangement and dimensions of the alignment mark, (a) B. Diffracted light of a predetermined order as the No. 1 light is set. It is possible to prevent the light flux of the diffraction order from reaching and converging on the light receiving area of the detection unit.

(b) Edge scattered light from a circuit pattern on the object surface can be prevented from reaching the light receiving area of the detection section.

(c) 1st. It is possible to suppress positional deviation measurement errors that occur due to distance fluctuations between the second objects, relative surface inclinations, and relative positional fluctuations in a direction perpendicular to the positional deviation detection direction.

A position detection device having the following characteristics can be achieved.

[Brief explanation of drawings]

FIG. 1 is a perspective view of essential parts of the first embodiment of the present invention, FIG. 2 is an xz sectional view of FIG. 1, FIG. 3 is an xy sectional view of FIG.
The figure is a schematic diagram of the main parts of the second practical 7iK example of the present invention, and Figure 5 (A
) is a schematic diagram of the main parts in which the first embodiment of FIG. 1 is applied to a proximity type semiconductor manufacturing apparatus, FIGS. Figure 6 is a schematic diagram of the main parts of a conventional position detection device, and Figure 7 is a (t, -1o
)-order light and (0, -1, 1)-order light. In the figure, 1 is the first object (mask), 2 is the second object (wafer), 3, 4, and 5.6 are alignment marks, and 7.8
are the first. 2nd signal beam; 9, wafer scribe line; 10, mask scribe line; 11.12, detection unit; 13, light source; 14, collimator lens system; 15, half mirror;
Reference numeral 8 indicates a processing section A and j, and reference numeral 19 indicates a wafer stage drive control section.

Claims (4)

[Claims] (1) When detecting a relative positional shift between a first object and a second object that are arranged opposite to each other, two alignment marks A1 and A2 that perform a wavefront conversion action are provided on the first object surface, and the second
Two alignment marks B1 and B2 that perform a wavefront conversion effect are provided on the object surface, and the light beam from the light projecting means is aligned with a reference plane formed by the normal to the first object surface and a direction perpendicular to the positional deviation detection direction. The first light beam and the light beam from the light projecting means are made obliquely incident on the first object surface from one side, and the first light beam and the light beam from the light projecting means are subjected to a wavefront conversion effect at the alignment mark A1 and the alignment mark B1, respectively, and the reference plane is from the other side to the border
A second beam of light is made obliquely incident on the object surface, and the second beam of light is subjected to a wavefront conversion effect at the alignment mark A2 and the alignment mark B2, respectively, and guided onto a predetermined surface, and the first beam of light and the second beam on the predetermined surface are The incident position of the two light beams is detected by a detection means,
A position detection device characterized in that a relative positional shift between the first object and the second object is detected using an output signal from the detection means. (2) Two alignment marks A on the first object plane
1 and A2 are formed separated by a predetermined amount in the positional deviation detection direction, and the incident angle of the light beam from the light projecting means that enters the two alignment marks A1 and A2 is equal to the angle of incidence from the surface of each alignment mark. 2. The position detection device according to claim 1, wherein the reflected light beams are set so as not to intersect with each other after exiting the first object surface. (3) Both the first and second light beams are subjected to an imaging action at the alignment mark, and the projection trajectories of the optical path of the first light beam and the optical path of the second light beam onto the first object plane intersect with each other. 2. The position detection device according to claim 1, wherein elements such as the direction of incidence of the two light beams, the angle of incidence, and the pattern shape and arrangement of each alignment mark are set so as to achieve the following. (4) Two alignment marks A on the first object plane
1. The emission angle of the principal rays of the first and second light beams subjected to the imaging action at A2 is incident within a predetermined plane that includes the positional deviation detection direction of the two alignment marks A1 and A2 on the first object surface. 3. The position detecting device according to claim 2, wherein the position detecting device is deflected from an angle.