JPS6355002B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a movable object positioning and positioning device comprising a radiation source and a radiation-sensitive detection system, the radiation-sensitive detection systems being arranged linearly with respect to each other in the direction of movement of the object. The present invention relates to a movable object positioning and positioning device, comprising at least two detectors having a radiation-sensitive detection system, such that the radiation distribution on the radiation-sensitive detection system is an indication of the deviation between the actual and desired position of the object. .

US Pat. No. 3,207,904 describes a device for positioning contact strips of a transistor. In this case, reflective strips are illuminated with a radiation beam and these strips are imaged by a microscope objective onto a radiation-sensitive detection system. The detection system is divided into four parts, each part having a mask behind which a radiation-sensitive element, such as a photoconductor or a radiation-sensitive semiconductor element, is arranged. By comparing the output signals of these radiation-sensitive elements, it is possible to determine the position of the contact strip or to detect the angular position of the transistor.

Optical position detection devices are used in many fields, in particular in devices for projecting mask patterns onto substrates, which projection devices are used in the manufacture of integrated circuits. The projection device includes a rotatable mask table on which the various mask patterns that need to be imaged during successive manufacturing steps can be placed. Furthermore, the projection device is equipped with a so-called substrate changer, with which the exposed substrate can be removed from the device and the substrate to be exposed can be placed in the device. Optical position sensing devices can be used to position both the substrate exchanger and the mask table.

In order to use an optical position sensing device for the above-mentioned purposes or for other purposes, for positioning rapidly moving objects with great accuracy, it is necessary that the object to be positioned be close to its desired position or angular position. It is necessary to indicate this at an early stage and adjust the moving speed of the object so that the desired position or angular position is reached at a sufficiently reduced speed.

It is an object of the present invention to provide a movable object positioning and positioning system that satisfies these needs.

The present invention provides a movable object positioning and positioning device comprising: a radiation source producing a radiation beam; a prism having at least two faces lying in two planes and defining an obtuse apex angle, the prism being arranged to capture the radiation beam over a predetermined range of movement of the movable object; said prism, each of said two faces serving to deflect radiation from said radiation beam at an oblique angle relative to its direction of incidence; first and second radiation detectors arranged to detect radiation deflected by the prism and arranged in fixed relation to said radiation beam incident on said prism; said first and second radiation detectors are adapted to cooperate to detect radiation deflected at said oblique angle over a range of object movement significantly greater than the combined width of said radiation detectors; 2 radiation detectors.

The apex angle of the prism is large (for example, about 165°)
Therefore, the amount by which the beam shifts on the radiation beam detector due to the relative deviation between the prism and the radiation beam is considerably small, and therefore even if the prism deviation with respect to the radiation beam is large, the amount of deviation of the beam on the radiation beam detector is quite small. The amount of radiation reaches the detector. When using a radiation-transmitting prism or a radiation-reflecting prism under certain conditions,
Lock in at a magnification of 2/α ² or 1/2α ² , respectively (
It can be proven that the range can be expanded. Here α is the base angle of the prism in radians.

To determine the position of an object in one direction, a prism with two inclined surfaces and two radiation beam detectors are used. If it is necessary to determine the position of an object in two mutually orthogonal directions, it is necessary to use a prism with four inclined surfaces and four detectors.

In apparatus for positioning an object, a reflecting prism is used which splits the radiation beam into two sub-beams and reflects each of these sub-beams towards a detector so that the radiation distribution on the detector is U.S. Pat.
It is known as described in the specification of No. but,
The purpose of this prism is not to extend the lock-in range. The detector, in this case a phototube for example, has a relatively large radiation-sensitive area. In addition, the apex angle of the prism in the known device is approximately 90°,
The base angle of this prism is approximately 45°.

In the movable object positioning and positioning device according to the invention for detecting the angular position of a rotating object, a lens is arranged between the radiation source and the prism, and the focal length of this lens is set to the distance between the axis of rotation and the lens. Make equal. This lens ensures that the chief ray of the beam is always incident on the prism at the same angle. This lens can be a cylindrical lens, the axis of which is parallel to the axis of rotation of the object.

Preferably, the prism is connected to the object whose position is to be detected, and the other elements of the movable object positioning and positioning device are fixedly arranged.

In order to make the configuration of the device of the present invention compact,
Preferably, the prism is a reflective prism.

In the case of a reflecting prism, the lock-in range is maximized and the construction is compact by making the principal ray of the beam emitted by the radiation source at an angle different from 90° with the refractive edge of the prism.

Separate optical elements such as optical fibers, lenses, etc. can be used to focus the beam reflected by the prism. In the device according to the invention, a mirror is further arranged between the prism and the illumination lens system forming a radiation spot on the prism, and these mirrors direct the beam reflected from the prism to the pupil of the illumination lens system. It is preferable to make it reflect. In this case, the illumination lens system is also used to focus the reflected beam onto the detector.

Furthermore, by placing a mirror between the radiation source and the illumination lens system, an image of the radiation source is formed near the radiation source, which allows the radiation source, which can be a light emitting diode (LED), to be connected to the detector. can be placed on one support.

The movable object positioning and positioning apparatus of the present invention can be used in apparatus for imaging a mask pattern onto a substrate, having a mask table and a substrate exchanger that require rapid and accurate positioning. In such a mask pattern imaging system, the elements of the first movable object positioning and positioning apparatus are preferably coupled to the mask table and the elements of the second movable object positioning and positioning apparatus are coupled to the substrate exchanger.

The drawings will be explained below.

FIG. 1 shows the principle of a known device for determining the position of an object relative to a reference position and for positioning the object. The device comprises a beam source B emitting a beam b. The lens system L concentrates the radiation from the beam source in the plane of the detection system D. Although it is possible to form a sharp image B' of the beam source B by means of this lens system L, this is not absolutely necessary. If it is necessary to detect the position of an object only in one direction (the x direction in FIG. 1), the detection system D comprises two detectors (for example photodiodes) D ₁ and D ₂ , which The separation line is perpendicular to the x direction. The output signals of these detectors are fed to the input terminals of a differential amplifier A, whose output signal is shown in FIG.
This is a measure of the deviation between the desired position and the actual position of the object. This object is coupled to one or more elements of a positioning and positioning device, for example a lens system L as shown in FIG. The output signal of differential amplifier A is applied to an object control system, shown diagrammatically as block C in FIG.

If the object is in the correct position, beam source B
The image B′ of is located symmetrically with respect to the detectors D ₁ and D ₂ and the output signals of these detectors are equal to each other. If the object is shifted to the left or right with respect to the desired position, the output signals of the detectors D ₁ and D ₂ are not equal to each other. The controller C therefore moves the object to the right or to the left until the detector signals are equal to each other.

If it is necessary to inspect the position of an object in two mutually orthogonal directions, the detection system D may include four detectors D ₁ , D ₂ , D ₃ , D ₄ as shown in FIG. It is necessary to Detectors D ₃ and D ₄ are connected to another (second) differential amplifier (not shown) whose output signal is connected to another (second) control for moving the object in the direction orthogonal to the x direction. equipment (not shown).

FIG. 3 shows the variation of the output signal E _s of the differential amplifier A as a function of the position S. The position S _p is the desired position of the object. If the object is at position S ₁ or S ₂ ,
Image B' is completely above one detector. The size of the positioning range p is approximately equal to M·e. Here M is the magnification of the lens system L and e is the diameter of the beam (radiation) source B. If the object is at position S ₃ or S ₄ , the chief ray of beam b is incident on the edge of the detector. If the object moves further outward, beam b is incident completely outside the detector;
Position detection is no longer possible. Positions S ₃ and S ₄
The range in between is the lock-in range.

In order to be able to use it for a variety of objects, it is generally necessary to position rapidly moving or large objects with great accuracy, and it is important to know early on that the object is approaching the positioning range. must be displayed to achieve proper control and to prevent overshooting of the object. In this case, measures can also be taken to adjust the speed of the object so that it reaches the positioning range at the desired relatively slow speed. For this purpose, it is detected whether the object has passed one of the limits of the lock-in range, ie one of the edges near the points S ₃ and S ₄ of the E _s curve in FIG. Therefore, in the above case, it is desirable to provide a maximum lock-in range I.

The lock-in range of known devices is limited by the width d of the detector and by the vignetting that can occur if the deviation is large. If the beam source B or the detection system D is coupled to a movable object, the lock-in range I is 2d. If detectors D ₁ and D ₂ are photodiodes, d
is relatively small, for example 2 mm, and the beam b is immediately located outside the detection system D. If the lens system L is coupled to an object, the lock-in range I is (assuming no vignetting) I=
It is given by 2d/M. Here, M is the magnification of the lens system. Therefore, the lock-in range can be increased by decreasing M. However, reducing M is inconvenient, especially when it is necessary to make the device compact and therefore to shorten the focal length of the lens system.

In a device that uses a lens system L to form an image of the beam source on the detection system, if M is to be reduced while the overall length of the device remains the same, the focal length of the lens must be shortened, and at the same time the movable It is necessary for the lens to receive the beam over the entire enlarged lock-in range. In this case, a lens system is required with a relatively short focal length and a relatively long diameter, ie at least equal to the increased lock-in range. In other words, a lens system with an impossibly large numerical aperture is required. This solution is therefore hardly practical.

According to the present invention, by providing the prism P with a small base angle α and a large apex angle β in the optical path, it is possible to enlarge the lock-in range with respect to a specific positioning range. 4 and 5 show an embodiment of the device according to the invention with a radiation-transmitting prism and a radiation-reflecting prism, respectively. Radiation-reflecting prisms have the advantage over radiation-transmitting prisms that the device according to the invention can be made more compact and that no optical conditions need to be imposed on the object.

In the device according to FIGS. 4 and 5, the radiation spot formed by the lens system is divided by a prism P. The secondary beam formed by this
b ₁ and b ₂ are received by photodiodes D ₁ and D ₂ . The position at which the sub beams are incident on the photodiode does not matter as long as the principal rays of these beams are incident on the photodiode.

If it is necessary to detect the position of an object in two mutually perpendicular directions, it is necessary to use a prism according to FIG. 6, ie a prism with four inclined surfaces. Each of these faces is a secondary beam
b ₁ , b ₂ , b ₃ and b ₄ with associated detectors D ₁ , D ₂ , D ₃
and reflect towards D ₄ .

Preferably, the prism P is coupled to a movable object;
The beam source B, lens system L, and detection system D are fixed. However, it is also possible to have a fixed arrangement of the prism 2 and to connect the other elements B, L and D to a movable object.

The device according to the invention allows the secondary beam to have a fairly small lateral deviation if the prism P has a certain linear deviation relative to the beam b and the angle through which the secondary beam is deflected remains constant. It uses the fact that it undergoes transfer. Therefore, even if the deviation between the actual and desired position of the object is large, the secondary beam will be incident on the detector. Since the deviation of the secondary beam is smaller than the deviation of the prism with respect to the illumination beam b, problems with vignetting when the beam is captured by the detectors, i.e. when reimaged onto these detectors. The risk of this occurring is reduced.

FIG. 7 shows how far the sub-beam moves when the prism is displaced over a distance s in the case of a radiation-transmitting prism. The amount of deviation δ, that is, the angular difference between the beam incident on the prism P and the beam split by this prism, is given by the well-known law of refraction n·sin α=n ₁ ·sin α ₁ . where α is the angle of incidence of the beam on the inclined surface of the prism, α ₁ is the angle between the deflected beam and the normal to said inclined surface, n and n ₁ are respectively the prism material and the refractive index of air. If the angles α and α ₁ are small, the following equation is satisfied:

nα=α ₁ (when n ₁ = 1) Therefore, the deviation amount δ=(α ₁ −α) is δ=(n−1)
becomes α. In the case of a glass prism with n=1.5, this deviation amount is δ=0.5α. Figure 7 shows that the beam deviation amount Δ is Δ=h・sinδ (here h=s・tanα), so when α and δ are small, Δ=s・α・δ=0.5α ² s Therefore, it clearly shows that s=2Δ/α ² . In the case of a one-to-one image of the beam source, the deviation Δ must not exceed the width d of the photodiode, so the maximum deviation of the object to the left or right that can be detected is s _nax
becomes s _nax =2d/α ² . In the case of a position detection device without a prism, the maximum measurable deviation is equal to d. Therefore, the expansion rate of the lock-in range is approximately 2/α ² . Here α is expressed in radians. In the case of a thin prism, that is, a wedge-shaped prism, the deviation amount δ
Since is approximately constant regardless of the position of the prism, the above also applies when beam b is first incident on the inclined surface of the prism.

FIG. 8 shows, in the case of a reflecting prism, how much the sub-beam is displaced when the prism is displaced over a distance s relative to the illumination beam. In this case, the following equation is satisfied for the deviation amount Δ.

Δ=h′sin2α where h′=s・tanα. Therefore, if the angle α is small, Δ=s·2α ² and s=Δ/2α ² . For a one-to-one image of the beam source, the magnification of the lock-in range is approximately 1/2α ² .

FIG. 9 diagrammatically shows the amount of expansion of the lock-in range. I ₁ indicates the lock-in range without a prism, and I ₂ indicates the lock-in range of the device with a prism. In an example using a reflecting prism with a base angle α of about 6.5°, I ₂ can in principle be approximately 37·I ₁ .

In Figures 7 and 8 only the chief ray of the beam is shown. The incident beam is a focused beam that forms a radiation spot at the location of the prism. The prism extracts two or four diverging beams from the incident beam. To prevent the beam diameter from increasing at the detector location (larger beam diameter requires larger detector surface),
Various measures can be taken. Preferably,
Two additional lenses L ₁ and L ₂ are placed between the prism and the photodiode as shown in Figure 10a.
are arranged such that these lenses couple the radiation spot onto the photodiode.

Alternatively, the sub-beams b ₁ and b ₂ can be captured by two optical fiber guides F ₁ and F ₂ placed close to the prism, as shown in FIG. It can have a large aperture and a small aperture at the photodiode location.

Furthermore, as shown in FIG. 10c, two light diffusing objects H ₁ and H ₂ are arranged behind the prism, which allow the radiation to be detected when the sub-beam is incident on them. It is possible to make the light incident on the vessel. In order to increase the amount of radiation on the detectors D ₁ and D ₃ , light diffusing objects can be used.
Lens between H ₁ and H ₂ and detectors D ₁ and D ₂
L ₃ and L ₄ can be placed respectively.
In the devices according to FIGS. 10a, 10b and 10c, measures can be taken to ensure that the secondary beam completely covers the pupil. In this way, vignetting will not occur if the prism is deflected. The reason is that in this case the deviation of the sub-beam corresponds to only a part of the diameter of the pupil.

In the above description, it is assumed that the object to be positioned moves along a line. However, the device according to the invention can also be used to detect the angular position of rotating objects. In this case, additional measures have to be taken to ensure that the illumination beam is always incident on the prism at the same angle. For this purpose, a lens is placed close to the prism, which lens ensures that the chief ray of the illuminating beam is always parallel to the imaginary connecting line between the axis of rotation of the prism and the refractive edge of the prism. Make it. This lens can be a cylindrical lens. The reason is that lens action is required only in one direction.

Figures 11 and 12 show two examples of devices comprising reflective prisms for detecting the angular position of rotating objects. In these figures, the axis of rotation of object V is RA
Indicated by R indicates a connecting line between the axis of rotation and the vertex of the prism P, and CL indicates a cylindrical lens. The axis CA of this cylindrical lens must be parallel to RA. The focal length f _CL of this lens must be equal to the distance r between the center of this lens and the axis of rotation RA.

As shown in FIG. 11, when the prism is placed on the object V and the rest of the optical system, i.e. the beam source, lens system and detector is fixedly placed inside the outer casing H, the cylindrical lens is placed at f _CL = -r, which is a negative lens. As shown in FIG. 12, when the prism P is fixed and the rest of the optical system moves together with the object, the cylindrical lens is a positive lens with a focal length of f _CL =+r.

The example shown in FIG. 11 can be used in an apparatus that repeatedly images a mask pattern on a substrate during the manufacture of integrated circuits. In this case, the substrate is exposed multiple times through the mask pattern, and the substrate is moved relative to the projection system the desired distance between two successive exposures. After all of the substrate has been exposed through the mask pattern, the substrate is removed from the apparatus so that it can be subjected to other processing. A new substrate can then be placed in the apparatus and exposed through the same or other mask pattern. A so-called substrate exchanger is used to remove such exposed substrates and place unexposed substrates into the apparatus.

Because integrated circuits are manufactured through multiple processing steps,
Various mask patterns are imaged onto the substrate.
In order to arrange various mask patterns within the apparatus, a so-called mask table is used on which a plurality of, for example two, mask patterns can be arranged. Both the substrate exchanger and the mask table can be positioned using the device according to the invention.

FIG. 13 shows an example of an apparatus for repeatedly imaging a mask pattern on a substrate. For example, mercury lamp LA,
A projection system comprising an elliptical mirror EM, an element I _o that homogenizes the radiation distribution in the illumination beam and a condenser lens C _p illuminates a mask pattern M ₁ arranged on a mask table MT. A second mask pattern _M2 can be placed on this mask table. By rotating this mask table about its axis MA, the second mask pattern _M2 can be moved into the projection system. The beam passing through the mask pattern M ₁ passes through a projection lens system PL shown diagrammatically, which forms an image of the mask pattern on the substrate. The substrate W is placed on a substrate table WT provided with an air cushion. Projection lens PL and substrate table
The WT is mounted in an outer case HO, and the outer case is sealed at the bottom by a bottom plate BP made of, for example, granite, and at the top by a mask table. The projection device is further provided with a substrate changer WC which is rotatable about an axis WA, the substrate changer being further adjustable in height. For other details on the construction and operation of the projection device, see the literature “Solid State Technology”,
Chapter “Step-and-Repeat” June 1980, pp. 80-84
Wafer Imaging”.

In order to be able to position the mask table when the mask is placed in the projection beam, a reflective prism P ₁ and a negative lens L ₅ are arranged on the mask table according to the invention. Prism P ₁ reflects the beam emitted by source-detection unit H ₁ ' to this unit, where it is received by a detection system comprising two detectors as described _above . The difference signal of these two detectors is used to position the mask table by means known per se (and therefore not described in detail). By using these position detection devices P ₁ , L ₅ and H ₁ ', the rotational speed of the table can be reduced, and the rotational speed of the table can be reduced, since the signal that brings the mask table closer to the desired position can be generated quickly and at a sufficiently slow speed. Reach the desired position. In order to position the second mask pattern _M2 , a second prism-lens pair _P2 , _L6 can be provided at a position diametrically opposed to the first prism-lens pair _P1 , _L5 .

Prism is used to position the board exchanger WC.
P ₃ , lens L ₇ , and beam source-detection unit
An analog position sensing device having H ₂ ′ is provided.
Prism P ₃ and lens L ₇ are fixed, and the beam source-detection unit is placed on a moving substrate exchanger, allowing for a compact configuration. lens
L ₇ is a positive lens.

In a positioning and positioning device having a reflecting prism in which the principal ray of the illuminating beam is incident perpendicularly to the refractive edge of the prism, the principal rays of the reflected beams b ₁ and b ₂ are respectively It is located on one side of the non-reflected beam b, and furthermore, the chief rays of all the beams are located in one plane. Care must be taken to ensure that the reflected beam does not overlap the irradiated beam. In order to separate the beams correctly, the base angle α of the reflecting prism must satisfy sin α sin α ₁ . Here α ₁ is the aperture angle of the projection system on the prism side. To increase the lock-in range, α must be minimized, so in practice α is approximately equal to α ₁ .

In order to make the configuration of the positioning and positioning device more compact and to further increase its lock-in range, it is preferable to tilt the prism P slightly with respect to the chief ray of the irradiation beam b. In this case the 14th
As shown in figure b, the chief ray of the reflected beam is located in a different plane than the chief ray of the illumination beam b. The reflected beams b ₁ and b ₂ can thus be located close to each other and the base angle α' can be smaller than the base angle α in FIG. 10a.

The reflected beams b ₁ and b ₂ can be focused onto the photodiode by a lens, in which case a lens and its associated photodiode can form a unit.

In a practical example of the device according to FIG. 14b, the lock-in range was approximately ±10 mm. This range is prism P
Determined by the dimensions of

In a positioning and positioning device with a reflecting prism, the projection lens system L can also be used to focus the beam reflected by the prism P onto the detector. For this purpose, it is necessary to place an additional mirror AM for each reflected beam between the prism P and the lens system L, as shown in FIG. For the sake of simplicity, FIG. 15 shows the mirror reflected by the upper part of the prism P.
Only the optical path of the beam b ₁ directed by the AM to the detector D ₁ is shown. The chief rays of beams b and _b1 are shown by dashed lines.

The radiation spot formed by prism P and mirror AM is separated from beam source B, so that the detector can be arranged around this beam source. 4
In the case of a prism having two inclined surfaces and four auxiliary mirrors AM, four detectors D ₁ , D ₂ , D ₃ and D ₄ are arranged on the plane of the beam source B as shown in FIG. Place it inside.

The degree of separation between the beam source and the image of the beam source is determined by the angle θ. The angle at which the mirror AM has to be arranged depends on the aperture angle γ on the image side according to =γ−θ/2 if the beams no longer exactly overlap each other immediately after reflection. In this case, the base angle of the reflecting prism must be equal to γ. In this case, the position of the lens system is mirror AM.
and the optical axis is equal to l. Here l is the maximum pupil diameter of the lens system L.

The mirror AM must extend to such an extent that it can receive the reflected beams even if they are displaced parallel to themselves when the prism is displaced. In this case it is necessary to be able to move the sub-beams b ₁ and b ₂ over the pupil of the lens system L. Since the above-mentioned pupil is completely covered by the sub-beam when the prism occupies the central position, there is a risk that radiation will be lost due to the above-mentioned deviation of the prism. In order to minimize such losses, the 15th
A field lens FL, shown in broken lines in the figure, can be arranged between the mirror AM and the prism P. lens
The focal length of FL is made equal to the distance of this lens to the pupil of lens system L. In this case, the reflected beam always passes through the center of the pupil of the lens system L.

Also, in Fig. 15, beam source B and lens system L
By placing an auxiliary mirror AM′ between
The image of the beam source can be positioned very close to the beam source itself. In this case, the radiation source in the form of a light-emitting diode and the photodiode can be arranged on one support. mirror
AM' is arranged at an angle equal to or approximately equal to the angle γ with respect to the optical axis.

The mirror AM can be constructed from a block of material, for example glass, and the cross section of this block can be square. Two or four reflected sub-beams are reflected by the side surfaces of the block, in which case all reflected beams can be utilized if the sub-beams are incident on the side surfaces at a fairly large angle. The above-mentioned side surfaces can be internal or external reflective. A lens system L is arranged at one end of the above block, and a field lens FL is arranged at the other end.

Preferably the block ML as shown in FIG.
The end faces LS ₁ and LS ₂ are curved so that these end faces have a lens action. The end face LS ₁ functions as a lens system L, and the end face LS ₂ is a field lens.
Functions as FL. Lens element _LS2 has positive refractive power and its focal length is equal to the length of block ML.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a known device for determining the position of an object and locating the object; Fig. 2 is an explanatory diagram showing a radiation-sensitive detection system used in the device of Fig. 1;
4 and 5 are diagrams showing the device according to the invention with a radiation-transmitting prism and a radiation-reflecting prism, respectively. ,
FIG. 6 is a perspective view of a reflecting prism with inclined surfaces for use in the device according to the invention; FIGS. 7 and 8 are illustrations showing the beam deflection as a function of the displacement of the object relative to the radiation-transmitting prism and the radiation-reflecting prism, respectively; FIG. , FIG. 9 is a diagram showing the variation of the position signal as a function of object displacement in a device according to the invention, and FIGS. 10 a, b and c show different optics for concentrating the radiation reflected by the prism onto the detector. Figures 11 and 12 are diagrams showing the elements; Figures 11 and 12 are diagrams showing an example of a device for detecting the position of a rotating object;
The figure is a diagram showing an apparatus for projecting a mask pattern onto a substrate, and Figures 14a and 14b are diagrams showing the case where a reflecting prism is used and the irradiation beam is incident at right angles to the refracting edge and at 90°, respectively. Explanatory diagram showing optical paths when incident at different angles, No. 15
16 is a diagram showing the arrangement of the detector relative to the beam source in an example of the device according to the invention, FIG. 17 is a diagram showing an example of the device according to the invention with an additional mirror for the reflected beam; FIG. 2 is a diagram showing an example of the device of the present invention in which the functions of an irradiation lens system and a mirror are achieved by an element. B... Beam (radiation) source, L... Lens system, D
...Detection system, D ₁ , D ₂ , D ₃ , D ₄ ...Detector, A...
... Differential amplifier, V ... Object, C ... Object control device, P, P ₁ , P ₂ , P ₃ ... Prism, L ₁ , L ₂ , L ₃ ,
L ₄ , L ₅ , L ₆ , L ₇ ... Lens, F ₁ , F ₂ ... Optical fiber guide, H ₁ , H ₂ ... Light diffusing object, CL ... Cylindrical lens, LA ... Mercury lamp, EM ... ...elliptical mirror,
C _p ...Condensing lens, _M1 , _M2 ...Mask pattern, MT...Mask table, PL...Projection lens system, W...Substrate, WT...Substrate table, WC
...Substrate exchanger, H' ₁ , H' ₂ ... Beam source-detection unit, AM, AM' ... Mirror, FL ... Field lens.

Claims (1)

[Scope of Claims] 1. A movable object positioning and positioning device comprising: a radiation source generating a radiation beam; and a ridge extending perpendicularly to the direction of movement of the movable object movably mounted with respect to the radiation beam. a prism having at least two faces lying in two intersecting planes and defining an obtuse apex angle, the prism being adapted to capture said beam of radiation over a predetermined range of movement of said movable object; said prism, each of said two surfaces serving to deflect radiation from said radiation beam at an oblique angle relative to its direction of incidence; first and second radiation detectors arranged to detect radiation deflected at an oblique angle of and arranged in fixed relation to said radiation beam incident on said prism; said first and second radiation detectors are adapted to cooperate to detect radiation deflected at said oblique angle over a range of object movement significantly greater than the combined width of said radiation detectors; 1. A movable object positioning and positioning device comprising: first and second radiation detectors. 2. In the movable object positioning and positioning device according to claim 1, which detects the angular position of a rotating object, a lens is disposed between the radiation source and the prism, and the focal length of the lens is aligned with the axis of rotation. A movable object positioning and positioning device characterized in that the distance between the movable object and the lens is equal to the distance between the movable object and the lens. 3. A movable object positioning and positioning device according to claim 1 or 2, characterized in that a prism is connected to the movable object. 4. A movable object positioning and positioning device according to any one of claims 1 to 3, characterized in that the prism is a reflecting prism. 5. In the movable object positioning and positioning device according to claim 4, the angle between the chief ray of the beam emitted by the radiation source and the edge of the prism is different from 90°. A movable object positioning and positioning device characterized by: 6. In the movable object positioning and positioning device according to claim 4 or 5, a mirror is disposed between the prism and an irradiation lens system that forms a radiation spot on the prism, and A movable object positioning and positioning device characterized in that a beam reflected from a prism is reflected toward a pupil of an irradiation lens system. 7 In the movable object positioning and positioning device according to claim 6, mirrors are arranged between the radiation source and the irradiation lens system, and these mirrors direct the reflected beam passing through the irradiation lens system to the radiation source. A movable object positioning and positioning device characterized in that a radiation-sensitive detector is arranged around the radiation source. 8. In the movable object positioning and positioning device according to claim 6, a hollow reflector with a square cross section is arranged between the radiation source and the prism, and the end face of the hollow reflector acts as a lens. A movable object positioning and positioning device characterized in that: