JPH0465116A - Peripheral edge exposure device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a peripheral edge exposure apparatus that selectively exposes the peripheral edge portion of a wafer.

[Conventional technology]

In the semiconductor integrated circuit manufacturing process, resist applied to form fine patterns on wafers tends to peel off at the wafer periphery, and the peeled resist adheres to the wafer surface, causing adverse effects in subsequent processes. This has become a problem.

Conventionally, in order to prevent resist peeling at the wafer periphery, which has such a negative effect, for example, Japanese Patent Application Laid-Open No.
As shown in Japanese Patent No. 56924, it has a mechanism for rotating the wafer in a plane substantially parallel to the surface of the wafer, and also rotates the exposure light beam shaped into a predetermined shape and the wafer in the radial direction of the rotation of the wafer (hereinafter simply referred to as "wafer rotation"). radial direction.)
It is said that only the peripheral portion of the wafer is selectively exposed using a dedicated exposure device that has a mechanism that can move relative to the wafer and a servo operating mechanism that irradiates the wafer within a predetermined range in the radial direction from the wafer edge. things are being done. Here, the shape of the exposure light flux is not circular (fan-shaped, rectangular, etc.) so that exposure can be performed with the minimum necessary exposure amount.

[Problem to be solved by the invention]

However, in the conventional technology as described above, the peripheral edge of the wafer can be exposed almost uniformly with a constant width, but the peripheral edge can be exposed at a constant width in the OF area (a linear flat area provided in the peripheral area). It was not possible to expose uniformly across the width.

This is because the exposure light beam can only move in the radial direction of the wafer. In other words, even if the servo operation follows perfectly, when exposing the OF part, the actual trajectory 11 drawn by the tip of the cross section of the exposure light beam (in this case, the cross section of the light beam is assumed to be rectangular) is curved as shown in FIG. 7, does not satisfy the required locus 12 of the tip of the beam cross section, and the exposure width does not fall within a predetermined range in the radial direction of the wafer (if the locus 11 is a straight line parallel to the OF part) This is because the trajectory will not be as follows.

In other words, in the conventional technology, even if a servo operation is performed to keep the predetermined width W in the radial direction of the wafer constant in FIG. A deviation d occurs. Furthermore, as shown in FIG. 7, the deviation d becomes larger as the exposure light flux moves toward both ends of the OF section, tilting with respect to the wafer ○F section.

Therefore, the trajectory of the leading edge of the light beam does not follow a trajectory that falls within a predetermined range required by the deviation d, and there is a problem that the peripheral exposure width is not constant.

This deviation d is defined as the angle θ between the perpendicular bisector 13 of the OF linear section that intersects with the wafer's rotation center and the straight line 14 that connects the wafer's rotation center and the end of the OF section. , it can be expressed as d=W−Wcosθ−(1). For example, in the case of a 6-inch wafer, the OF linear length is 57.5 mm, and the peripheral edge exposure width (W) is 5.
In the case of mm, d=about 0.38 mm.

On the other hand, when exposing the OF part, since the exposure light flux is tilted with respect to the OF part, the cumulative exposure amount in the trajectory drawn by a point at the corner of the exposure light flux and the trajectory drawn by a point near the center of the exposure light flux are The cumulative exposure amount is different. This difference in cumulative exposure becomes larger toward the OF end. This means that the exposure light flux decreases as it approaches both ends of the OF section, as shown in Figure 8.
Deviation d at the OF end because it acts at an angle to the OF part
This is due to the fact that the impact of

Furthermore, the exposure light beam must have a certain area in order not to reduce the throughput (the thickness of the exposure light beam in the tangential direction to the wafer circumference must have a certain thickness), and This is because, due to the area, the influence of the deviation d increases toward the OF end (the dashed line in the figure indicates the radius of the wafer).

Therefore, the cumulative exposure amount is not constant near the OF end (shaded area in FIG. 7) after the peripheral edge exposure, and there is also the problem of causing film burrs at the resist ends and variations in the peripheral edge exposure width.

The present invention has been made in consideration of the above points, and
It is an object of the present invention to provide a peripheral edge exposure device that can control the exposure light flux so that the exposure width and cumulative exposure amount are constant even when exposing the F section.

[Means to solve problems]

In order to solve this problem, in the present invention, the substrate has a linear flat portion on the periphery and a substantially uniform photosensitive layer on the surface, and the substrate is centered near the center, and the substrate is moved in a plane substantially parallel to the surface. The first rotating means (1
, 3, 11) and an irradiation means (4) for irradiating the peripheral portion of the substrate with a light beam having a cross-sectional shape in which at least a portion is formed into a linear shape.
, 5) and a moving means (10) for relatively moving the light beam and the substrate in the radial direction of the rotation, and driving the moving means while rotating the substrate by the first rotating means. In the peripheral edge exposure apparatus that exposes the peripheral edge portion with the light beam, a detection means ( De, 8) and;
a second rotation means (9) for rotating the light beam around a center of the light beam in a plane substantially parallel to the surface;
and; control means (1) for controlling the second rotation means so that the flat part of the substrate and the linear edge of the cross-sectional shape of the light beam are approximately parallel to each other based on the signal from the detection means;
7).

[For production]

According to the present invention, by rotating the light beam, it is possible to uniformly expose the OF portion of the wafer with an accurately constant exposure width, so that the cumulative exposure amount at the peripheral portion is uniform over the entire circumference of the wafer, and the resist There is little film loss at the edges, and peripheral edges can be exposed with high accuracy.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram showing the overall configuration of a peripheral edge exposure apparatus according to a first embodiment of the present invention.

The wafer 2 is transported onto the turntable 1 along a wafer transport path (not shown), and the center of the wafer 2 is aligned with the turntable l.
is vacuum-adsorbed onto the turntable 1 at a position where the rotation centers of the two substantially coincide with each other. The turntable 1 is rotated by a motor 3 at a predetermined speed while holding the wafer 2.

Here, the motor 3 is provided with a rotary encoder 11, and the rotation angle of the turntable 1 can be detected.

Further, the light source 7 generates illumination light (exposure light) in a wavelength range that is highly sensitive to the resist, and this illumination light is guided by the fiber FB to the light emitting section 4 arranged above the peripheral edge of the wafer 2. . Further, the illumination light is turned into a substantially parallel light beam by a lens system 4a provided inside the light emitting unit 4, and is turned into a substantially parallel light beam at the diaphragm 5.
irradiate.

The illumination light from the light source 7 is defined (shaped) into a predetermined cross-sectional shape by the diaphragm 5, and is emitted from the light emitting section 4 as an exposure light beam 6, and is selectively irradiated onto the peripheral edge of the wafer 2.

Here, the aperture 5 adjusts the cross-sectional shape of the exposure light beam 6 as shown in FIG.
) is formed into a rectangular shape with at least the edge l on the wafer side being straight as shown by diagonal lines. For example, the diaphragm 5 is composed of two L-shaped light-shielding plates having a straight part that can form a straight edge l, and in this embodiment, the two light-shielding plates are referenced to the optical axis of the lens system 4a. The width and size of the light beam 6 can be adjusted. This rectangular shape is not limited to a rectangle, and may be a trapezoid or the like.

Next, the light receiving section 8 is arranged to face the light emitting section 4 with the peripheral edge of the wafer 2 in between.

The light receiving section 8 has linear position sensors (or silicon sensors) installed parallel to each other at intervals as shown in FIG.
Photodiodes, etc.) 8a and 8b are arranged to detect the light beam 6. Further, in this embodiment, the light emitting section 4. Separately from the light receiving section 8, a wafer outer shape detection sensor De as shown in FIG. ing. Then, before the peripheral edge exposure, the turntable is rotated and the non-exposure light that is not blocked by the wafer 2 is transferred to the sensor D.
Receive light at e. Wafer outline information (OF position,
The rotary encoder 11 directly connected to the turntable 1 detects wafer outer shape information as angle information.

It is assumed that the straight line portion 1 in the cross section of the light beam 6 and the light receiving portion 8 are predetermined in a certain correspondence relationship with respect to the inclination. Here, adjustment is made so that the linear portion 1 of the light beam 6 is perpendicular to the longitudinal direction of the sensors 8a and 8b provided in the light receiving section 8 ((Fig. 2(b)).

The sensors 8a and 8b receive the light beam 6 that is not blocked by the wafer 2, and the edge of one wafer 2 is detected based on the photoelectric signal output from each of the sensors 8a and 8b. Information regarding the inclination of the OF portion relative to the angle is detected. Detection of information regarding this inclination is obtained from the output difference (difference in voltage value) between the sensors 8a and 8b. (If the OF section is tilted with respect to the longitudinal direction of the sensor, a difference in output will occur between 8a and 8b)
The light emitting section 4 and the light receiving section 8 are integrally fixed to a metal fitting 21 to form an exposure unit U. Further, the metal fitting 21 is fixed to the slider (movement stage) 10a. The moving means 10 includes a moving stage 10a on which the exposure unit U is placed,
Guide 10b.

Composed of a motor 10c, the exposure unit U is connected to the wafer 2.
By making it movable in the radial direction, the light beam 6 and the wafer 2 can be moved relative to each other.

The exposure unit U is configured to be rotatable along a plane substantially parallel to the surface of the wafer 2 by a motor 9 about the approximate center of the light beam 6 (the optical axis of the lens 4a).

As described above, by driving the light shielding plate with the optical axis of the lens system 4a (the approximate center of the light beam 6) as a reference, even if the shape of the light beam 6 changes, the approximate center of the light beam 6 and the rotation center of the exposure unit U ( The relative positional relationship with the optical axis of the lens 4a does not change.

It is also possible to set the rotation center at a point other than the approximate center of the light beam 6 (the optical axis of the lens 4a);
It is desirable to set the approximate center of (optical axis of lens 4a) as the center of rotation. In the case of the above configuration, the rotational moment is reduced and rotation control becomes easy. Furthermore, when performing a servo operation in the radial direction of the wafer 2, which will be described later, there is an advantage that the amount of movement of the light beam 6 relative to the wafer 2 is small.

Next, exposure control of the wafer peripheral portion in this embodiment will be explained using the block diagram of FIG. 3.

The light receiving unit 8 outputs a signal corresponding to the light intensity (light amount) of the light beam 6, and the signal is sent to the amplifier 12. The data is stored in the RAM 14 via the A/D converter 13 in response to clock pulses from the CPU 15.

It is assumed that the RAM 14 stores in advance data DI regarding the required exposure area of the peripheral portion and data D2 regarding the appropriate exposure amount for the resist used. Here, to explain the data D1 in more detail, the data DI is the calibration performed before the exposure operation of the wafer 2 (when a dummy wafer or the like is used before the wafer exposure operation is set to be exposed with the required exposure width). The sensor 8a corresponds to the required exposure width determined by (correlation between the required exposure width and the output signal voltage value from the sensor 8).

This is the voltage value of the output signal from 8b. The servo operation described later is based on the output voltage values from the sensors 8a and 8b and this data D.
This is done by comparing I.

When exposing the periphery of the wafer 2, the CPU 15
The appropriate exposure amount is calculated based on the data DI related to the required exposure area of the peripheral portion stored in M14 and the data D2 related to the appropriate exposure amount for the resist used, and the exposure condition (
(exposure light intensity, aperture width, etc.) and the rotation speed of the turntable 1 are determined.

Then, the CPU 15 generates data D2 regarding the exposure light intensity.
' to the light source 7, a luminous flux shape signal E that controls the aperture 5 to shape the luminous flux into a predetermined shape, to the aperture control section 16, and a control signal that controls the motor 3 so that the turntable 1 has a predetermined rotation speed. F to the first rotation control section 19, respectively. The aperture 5 is controlled so that the center of the luminous flux and the rotation center of the unit U remain unchanged.

After the rotation of the wafer starts, the light emitting section 4 and the light receiving section 8 are arranged so as to sandwich the peripheral edge of the wafer 2 by the driving means 10 at a position corresponding to the required exposure area, and then an exposure start signal D is applied.
3' (turning on the light source 7) is transmitted to the light source 7 by the CPU 15, so that the exposure light beam 6 is emitted from the light emitting section 4.

Further, when the turntable 1 rotates at a predetermined speed and exposure is started, the light receiving section 8 receives the exposure light beam 6 emitted from the light emitting section 4. The CPU 15 compares the signals (voltage values) from the sensors 8a and 8b with the data D1 stored in the RAM 14, and controls the moving element so as to always expose an area up to a predetermined distance from the wafer edge in the wafer circumference. A servo control signal G for controlling stage 10 is sent to servo control section 18 .

In this embodiment, the wafer outer shape is detected before exposure, and the OF part information is associated with the angle information of the encoder, and the RA is
It is stored in M14.

When exposing the OF portion, the OF portion and the circumferential portion are determined based on the angle information of the encoder corresponding to the OF portion stored in the RAM 14.

Furthermore, as shown in FIG. 4, the CPU 15 transmits output difference (voltage difference) signals from each sensor of the light receiving section 8, which is composed of two position sensors 8a and 8b arranged at intervals, to the sensors 8a and 8b. This is detected as information regarding the inclination of the OF section.

Based on this output difference, the CPU 15 determines whether the exposure light flux 6 is OF
in the section, so that this output difference becomes zero, that is, OF
A control signal H for the motor 9 is sent to the second rotation control unit 17 to rotate the light beam 6 with respect to the edge of the OF portion so that the edge of the OF portion and the straight line portion l of the light beam 6 are substantially parallel. the result,
The second rotation control unit 17 controls the rotation of the motor 9 so that the linear edge l of the cross section of the light beam 6 and the OF portion are approximately parallel to each other.

When the exposure is completed with the proper exposure amount, the CPU 15 sends an exposure end signal D3'' to the light source 7, and also stops the rotation of the motor 3 via the first rotation control means 19, thereby ending the edge exposure.

Next, the operation of this embodiment will be explained with reference to FIG.

First, in step 100, before the exposure operation, the turntable on which the wafer 2 is placed is rotated once, and the sensor D
e, the OF portion is detected in a non-contact manner, and the position information D4 of the OF portion is stored in the RAM 14 as angle information of the encoder 11 in accordance with the encoder pulse.

Next, in step 101, the CPU 15 uses the signal obtained from the light receiving section 8 and the data Di stored in the RAM 14 in advance.
, D2, the exposure conditions (intensity of exposure light, aperture width, etc.) and the rotation speed of the turntable 1 are determined.

Based on these conditions, data D2 regarding exposure light intensity
' to the light source 7, the beam shape signal E to the aperture control section 16,
Control signals F for the motors 3 are sent to the first rotation control section 19, respectively.

Here, as described above, the aperture 5 is capable of adjusting the width of the light beam 6 using two light shielding plates.

When determining the rotational speed of the turntable 1, if the intensity of the exposure light is constant, to increase the rotational speed of the turntable 1, narrow the slit width of the aperture 5, and conversely, to decrease the rotational speed, narrow the slit width. The width may be increased.

In addition, when confirming whether the exposure conditions set during exposure are appropriate, it is possible to receive the exposure light with the light receiving section 8 with the wafer 2 removed and actually measure the intensity of the exposure light beam 6. It is possible to prevent changes in exposure amount due to deterioration, etc. If the intensity of the exposure light beam becomes weak due to deterioration of the light source, etc., the rotation speed of the turntable 1 may be lowered, but the rotation of the turntable 1 may be reduced by widening the aperture width by an amount corresponding to the degraded amount of light. It is also possible to ensure a predetermined exposure amount while keeping the speed constant.

This is advantageous in keeping the throughput constant.

Next, in step 102, the first rotation control unit 19 receives the motor 3 control signal F from the CPU 15, starts rotating the motor 3, controls the motor 3, and rotates the turntable l at a predetermined speed.

Next, the exposure unit U is arranged by the moving means 10 so as to sandwich the peripheral portion of the wafer 2 at a position corresponding to a preset required exposure area.

Next, in step 103, the exposure start signal D3° is sent to the CPU 15.
The light source 7 is turned on by being sent from the light source 7 to the light source 7, and the exposure light beam 6 is emitted from the light emitting section 4.

The CPU 15 can detect the wafer OF portion from the encoder angle information (data D4) corresponding to the OF portion stored in the RAM 14.

In step 104, the CPU 15 determines whether it is the OF part or the circumferential part based on the angle information of the encoder 11, and if it is the circumferential part, in step 10-5, the CPU 15 receives the data D1 and the signal from the light receiving part 8. Based on this, a servo control signal G is sent to the servo control unit 18 so that the edge of the wafer 2 is always exposed with a constant exposure width. The servo operation is performed so that the signal from the sensor 8 and the data D1 are equal. The servo control unit 18 servo-controls the moving means 10 based on this signal G. As a result, a region extending to an arbitrary distance in the radial direction from the wafer edge is uniformly exposed with a constant width. (
At this time, it is assumed that there is no difference in output from the sensors 8a and 8b. ) If it is determined in step 104 that it is the OF section, the CPU 15 sends the control signal H for the motor 9 to the second rotation control means 17 based on the signal from the light receiving section 8 in step 200, and performs the second rotation control. The means 17 generates the exposure light beam 6 in the OF section.
so that the edge l on the wafer side and the OF part are always parallel.
A motor 9 is controlled to rotate the light beam 6. For example, as shown in FIG. 4, the CPU 15 controls the light emitting section 4 and the light receiving section 8 so that the sensor signals from the two sensors 8a and 8b are equal. It is sufficient to control them so that they rotate as one. At the same time, the servo control unit 18 performs servo control in the radial direction of the wafer 1 so that exposure is performed with a constant width.

This operation is continued until the light beam reaches the circumferential portion from the OF portion in step 201. (OF department.

The circumferential portion is determined based on the angle information of the encoder 11. ) When the beam 6 approaches the circumference, the edge l of the cross section of the beam 6
is approximately perpendicular to the radial direction of the wafer (sensor 8a,
8b), the motor 9 stops rotating the light beam 6, and in step 105, only the servo control in the radial direction of the wafer is performed as described above.

After the predetermined rotation is executed, the CPU 15 sends an exposure end signal D3'' to the light source 7 in step 106, turns off the light source 7, stops the turntable 1, and completes the peripheral edge exposure of - wafers. do.

Note that when the rotation of the exposure light flux and the movement of the wafer in the radial direction are simultaneously controlled, and the turntable l is rotated at a constant speed, the exposure light is The irradiation time becomes longer, and the amount of exposure increases especially at both ends of the OF portion.

Since the resist is usually in a raised state in the OF part, especially at both ends of the OF part, there is no particular problem even if the exposure time is longer in the OF part.

In addition, if it is necessary to expose with a uniform exposure amount all around,
The OF portion may be rotated at a higher speed than the circumferential portion.

As described above, in this embodiment, the lens system 4a and the diaphragm 5 are provided between the fiber FB and the wafer 2, and the fiber whose injection end is shaped into a rectangular shape is placed above the peripheral edge of the wafer 2. It may be placed very close to the wafer 2. In this case, the light beam 6 emitted from the fiber directly touches the wafer 2.
The exposure amount can be controlled by adjusting the rotation speed of the turntable 1.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the first embodiment, a predetermined exposure area is obtained by moving the exposure unit U that integrates the light emitting section 4 and the light receiving section 8 in the radial direction of the wafer. As shown in the figure, the light emitting unit 4 and the light receiving unit 8 perform only rotational operation, and the turntable 1 that holds the wafer 2 is placed on a stage 20 that is movable in the radial direction of the wafer.
By performing servo control of the stage 20, a predetermined exposure area is attempted to be obtained. The stage 20 has a motor 2. Ob allows the wafer to move on the guide 2Oa in the radial direction of the wafer. The other configurations are the same as in the first embodiment.

Next, a third embodiment of the present invention will be described.

In the first embodiment, the light emitting section 4 and the light receiving section 8 are integrated into an exposure unit U, and this exposure unit U is rotated integrally, but in this embodiment, the motor 9 It is assumed that only the light emitting section 4 is rotated. The other configurations are the same as in the first embodiment.

In this embodiment, as the light emitting unit 4 rotates, the exposure light beam 6 and the light receiving unit 8 relatively change (rotate).
An angle detection means such as a rotary encoder is provided at the When exposing the OF section, the sensor 8a of the light receiving section 8
, 8b, and the angle θ1 determined by the angle detecting means are equal to each other. Here, the method for determining the inclination of the light receiving section 8 and the OF section is as follows.
Based on the signals from two position sensors 8a and 8b spaced apart as shown in FIG. 4, the positions S, S2 of the OF section on each sensor are determined. Then, by calculating the difference between the positions S, , S2 and the known distance, the angle θ between the light receiving section 8 and the OF section can be determined as follows.

In this embodiment, it is assumed that the light beam 6 is shaped to such a size that the side surface K of the light beam does not come off the sensors 8a, 8b even when the light emitting section 4 rotates.

In order to prevent the tilt detection accuracy from decreasing, even if only the light emitting part 4 rotates, the sensor 8 on the outer side of the wafer 2
This is because it is necessary to receive the light beam 6 over the entire area a and 8b.

Incidentally, the angle detection means such as a rotary encoder uses a light beam 6
It is assumed that the counter is preset in advance when the straight line portion l and the sensors 8a and 8b are perpendicular to each other.

In this embodiment, since only the light emitting section 4 rotates, the light receiving section 8 remains tilted with respect to the OF section.

Therefore, when performing radial servo control of the wafer 2 regarding the exposure width, the output values from the sensors 8a and 8b are
It is assumed that servo control is performed using a value added with an offset amount according to the inclination.

On the other hand, the wafer length, which is known from the OF detection result before the exposure operation,
It is also possible to obtain the inclination of the OF portion by calculation by the CPU 15 using the wafer radius and perform rotation control without using the output values from the sensors 8a and 8b.

Next, a fourth example will be described.

In the first to third embodiments described above, the wafer outline information (OF detection information) was obtained before the exposure operation, and the wafer outline detection sensor De and the sensor 8 were configured separately, but in this embodiment, the optical system The configuration is such that the sensor De is shared by the sensor 8, with the sensor De being the same.

In this case, two light sources, one that emits exposure light and one that emits non-exposure light, are provided, and the light flux emitted from each light source is guided to the above-mentioned optical system via a dichroic mirror. Bye.

An example of switching between exposure light and non-exposure light is turning on the light source,
Possible methods include switching by turning it off or providing a shutter between the light source and the dichroic mirror to switch as appropriate. Alternatively, when using a broadband exposure light source such as a mercury lamp, a wavelength selection filter that selects only non-exposure wavelengths is provided in the optical path, and exposure light and non-exposure light are selected as appropriate by inserting and removing this filter. Just do it like this.

Before the exposure operation, the sensor 8 receives non-exposure light to detect wafer outline information. The following exposure operations are the same as those in the first to third embodiments.

Next, a fifth embodiment of the present invention will be described.

In the above embodiment, the timing for starting and ending the rotation of the light beam 6 (rotation of the entire exposure unit U or only the light emitting unit 4) was determined from the wafer outline information obtained before exposure, but in this embodiment, Since a difference in output occurs between the sensors 8a and 8b at the boundary between the OF part and the circumferential part, the timing for starting and ending the rotation of the light beam 6 is determined at the time when this difference in output is detected. Exposure is started from the circumferential part or the OF part, and by controlling the start and end of the rotation of the light beam 6 when the boundary between the circumferential part and the OF part is detected, control operations corresponding to each can be performed. Become.

Next, a sixth example will be described.

In the above embodiment, the light flux is guided from the light source to the wafer via a fiber, but in this embodiment, the light flux is guided from the light source located away from the wafer irradiation unit to the wafer using a mirror system. The structure is such that the light is guided through an optical system.

With this configuration, by driving the mirror system and optical system while keeping the turntable 1 fixed, it is possible to move or rotate the light beam in the radial direction of the wafer.

The light beam emitted from the light source is converted into uniform, substantially parallel light through an illumination system, shaped into a predetermined shape by an aperture, and then irradiated onto a wafer through a mirror system or an optical system. In order to move the light beam in the radial direction of the wafer in the same way as when the light emitting unit 4 was moved in the first embodiment, for example, a light emitting unit provided above the irradiated surface of the wafer at an angle of 45 degrees with respect to the wafer surface can be used. What is necessary is to move the mirror or provide an optical system such as a plane parallel optical system between the aperture and the wafer, and tilt them at a predetermined angle. This allows the wafer to be exposed with a predetermined width. Furthermore, when rotating the light beam, an image rotator may be provided between the diaphragm and the wafer in the parallel light path, and the image rotator may be rotated by 1/2 of the desired light beam rotation angle.

Furthermore, if it is desired to have a conjugate relationship between the aperture surface and the wafer surface, an afocal relay system is provided.

When moving the light flux in the radial direction of the wafer, the lens on the wafer side of the relay system and the mirror installed above the irradiation surface of the wafer at an angle of 45 degrees with respect to the wafer surface should be moved together, or a plane parallel method, etc. In order to rotate the light beam, the aperture may be rotated, or an image rotator may be provided in the optical path between the aperture and the wafer and rotated.

〔Effect of the invention〕

As described above, according to the present invention, the wafer OF with respect to the luminous flux is
Information about the inclination of the wafer is detected and controlled so that the wafer OF part always has a constant exposure width in the same way as the circumferential part of the wafer, so there is little variation in exposure width and film thinning over the entire wafer circumference. Peripheral exposure can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration according to the first embodiment of the present invention, FIG. b) is a diagram showing a light receiving section according to the first embodiment of the present invention, FIG. 3 is a block diagram showing exposure control according to the first embodiment of the present invention, and FIG. FIG. 5 is a flowchart showing the exposure operation according to the first embodiment of the present invention, and FIG. 6 is a diagram showing a method of detecting the angle of the OF portion according to the embodiment. FIG. 7 is a diagram showing the device configuration according to an example;
The figure is a diagram showing the locus of the tip of the light beam in the conventional technique, and FIG. 8 is a diagram showing the inclination of the light beam at both ends of the OF section in the conventional technique. [Explanation of symbols of main parts] 1... Turntable, 2... Wafer, 3, 9...
・Motor, 4... Light emitting section, 5... Aperture section, 6...
Luminous flux, 8... Light receiving unit, 10... Moving means, 15...
-CPU, 17...second rotation means control section, 19...
・First rotation means control section, De...sensor Fig. 2

Claims (1)

[Scope of Claims] A first method for rotating a substrate in a plane substantially parallel to the surface of the substrate, the substrate having a linear flat portion around the periphery and a substantially uniform photosensitive layer on the surface, about the center of the substrate. a rotating means, an irradiation means for irradiating a peripheral edge of the substrate with a light beam having a cross-sectional shape formed at least in a straight line, and a moving means for relatively moving the light beam and the substrate in the radial direction of the rotation. A peripheral edge exposure apparatus comprising: rotating the substrate by the first rotating means and driving the moving means to expose the peripheral edge part with the light beam, wherein the linear direction of the flat part and the light beam are a detection means for detecting information regarding an inclination relative to a direction of a linear edge in a cross-sectional shape; a second detection means for rotating the light beam around a center of the light beam in a plane substantially parallel to the surface; a control means for controlling the second rotation means based on the signal from the detection means so that the flat part of the substrate and the linear edge of the cross-sectional shape of the light beam are approximately parallel to each other; A peripheral edge exposure device comprising: and;