JP4882384B2 - Surface position detection apparatus, surface position detection method, exposure apparatus, and device manufacturing method - Google Patents

Description

The present invention relates to a surface position detection apparatus, a surface position detection method, an exposure apparatus provided with the surface position detection apparatus, and a device using the exposure apparatus used in a lithography process for manufacturing a semiconductor element, a liquid crystal display element, and the like. It relates to a manufacturing method.

  In a projection exposure apparatus that projects and exposes a pattern formed on a mask onto a substrate via a projection optical system, the projection optical system has a relatively shallow depth of focus, and the substrate surface may not be flat. It is necessary to accurately adjust the focus position with respect to the projection optical system in the exposure region on the substrate without lowering the image quality.

  As an apparatus for detecting the position of the substrate in the optical axis direction of the projection optical system, for example, an oblique incidence type that projects an image of a slit from an oblique direction onto a substrate as a test surface and detects the image of the slit from an oblique direction An autofocus sensor (surface position detection device) is known (see, for example, Patent Document 1).

JP-A-5-129182

  In the above oblique incidence type autofocus sensor, the detection light is reflected on the resist surface coated on the substrate surface by increasing the incident angle of the detection light incident on the substrate (for example, 84 degrees). ing. However, as shown in FIG. 6, a part of the detection light A <b> 2 enters the resist 20, passes through the resist 20, and is reflected by the surface of the substrate W. Here, since the size of the slit is finite, a measurement error occurs due to the state and structure of the substrate surface, and there is a problem that the focus position of the substrate with respect to the projection optical system cannot be measured accurately. It was.

  In addition, by setting the wavelength range of the detection light widely, it is possible to average the influence of interference due to the thickness of the resist, the state of the substrate surface multilayered with a metal film, etc., and the structure. There was a problem that a measurement error occurred.

An object of the present invention is to provide a surface position detecting apparatus, a surface position detecting method, an exposure apparatus provided with the surface position detecting apparatus, and a device using the exposure apparatus. Is to provide a method.

A surface position detection apparatus according to a first aspect of the present invention includes a light transmission optical system that irradiates a test surface with light through the predetermined pattern of a pattern member on which a predetermined pattern is formed from an oblique direction , and the An imaging optical system including a light receiving optical system that forms the aerial image of the predetermined pattern based on the light reflected by the test surface, and a position where the aerial image is formed, and the light passes therethrough A light receiving slit member having a possible light receiving slit , a scanning unit that relatively scans the aerial image and the light receiving slit in a predetermined direction, a photoelectric conversion unit that photoelectrically converts the light that has passed through the light receiving slit , Detecting means for acquiring a light intensity distribution of the aerial image formed on the light receiving slit based on a conversion result of the photoelectric conversion means, and detecting a surface position of the test surface based on the light intensity distribution; Preparation The width of the receiving slit for a given direction, characterized in that narrower than the width of the aerial image related to the predetermined direction.

The second surface position detecting method according to an aspect of the invention, the light through a predetermined pattern is irradiated from an oblique direction to the test surface, the on the basis of the light reflected by該被sample surface A space image forming step for forming a space image of a predetermined pattern, a light receiving slit that is disposed at a position where the space image is formed and through which the light can pass, and scanning that relatively scans the space image in a predetermined direction. Obtaining a light intensity distribution of the aerial image formed on the light receiving slit based on a conversion result of the step, a photoelectric conversion step of photoelectrically converting the light that has passed through the light receiving slit, and a conversion result of the photoelectric conversion step , Detecting a surface position of the test surface based on a light intensity distribution , wherein the width of the light receiving slit in the predetermined direction is narrower than the width of the aerial image in the predetermined direction. .

An exposure apparatus according to a third aspect of the present invention is an exposure apparatus that irradiates a photosensitive substrate with exposure light via a projection optical system, and detects a surface position of the photosensitive substrate with respect to the projection optical system. A surface position detecting device according to the first aspect is provided .

According to a fourth aspect of the present invention, there is provided a device manufacturing method comprising: an exposure step of exposing a photosensitive substrate using the exposure apparatus according to the third aspect; and the photosensitive substrate exposed by the exposure step. And a developing step for developing .

According to the surface position detection apparatus and the surface position detection method according to the second aspect of the present invention, the surface position of the test surface can be accurately determined without being affected by the structure on the test surface. Can be detected.

Moreover, according to the exposure apparatus concerning the 3rd aspect of this invention, since the surface position detection apparatus concerning the 1st aspect of this invention is provided , the structure on a photosensitive substrate, for example, coating on a photosensitive substrate The surface position of the photosensitive substrate can be accurately detected without being affected by the structure inside the resist. Therefore, the surface position of the photosensitive substrate can be accurately adjusted, and highly accurate exposure can be performed.

According to the device manufacturing method of the fourth aspect of the present invention, since the exposure is performed using the exposure apparatus according to the third aspect of the present invention, the surface position of the photosensitive substrate is accurately detected. The surface position of the photosensitive substrate can be adjusted accurately. Therefore, highly accurate exposure can be performed and a good device can be obtained.

  A projection exposure apparatus according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a projection exposure apparatus according to the first embodiment of the present invention. In the following description, the XYZ orthogonal coordinate system shown in FIG. 1 is set, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. The XYZ orthogonal coordinate system is set so that the X axis and the Y axis are parallel to the wafer W, and the Z axis is set in a direction orthogonal to the wafer W. In the XYZ coordinate system in the figure, the XY plane is actually set to a plane parallel to the horizontal plane, and the Z-axis is set vertically upward.

  As shown in FIG. 1, the exposure light emitted from the illumination optical system IL including the light source illuminates the reticle R placed on the reticle stage RST. The position of reticle stage RST is measured and controlled by a reticle stage interferometer (not shown). The exposure light that has passed through the exposure pattern formed on the reticle R projects a pattern image of the reticle R onto the wafer W placed on the wafer table WT via the wafer holder WH via the projection optical system PL. To do. Wafer table WT is placed on Z stage ZS, X stage XS, and Y stage YS as wafer stages. The Z stage ZS is configured to be movable in the focusing direction (Z direction) along the optical axis of the projection optical system PL, and the X stage XS and the Y stage YS allow the wafer W to be perpendicular to the optical axis of the projection optical system PL. It is configured to be capable of parallel movement and minute rotation within a plane (XY plane). The position of the wafer stage is measured and controlled by a wafer stage interferometer (not shown).

  This projection exposure apparatus includes a surface position detection apparatus 2. The surface position detection device 2 is configured to position the wafer W in the optical axis direction (Z direction) of the projection optical system PL so that the exposure area of the wafer W falls within the depth of focus with respect to the imaging plane by the projection optical system PL. Is detected.

  As shown in FIG. 1, the surface position detection device 2 includes a light transmission optical system SL and a light reception optical system RL. The light transmission optical system SL transmits detection light supplied from a light source (not shown) from an oblique direction onto a wafer W that is a surface to be detected, and transmits light transmission slits (predetermined patterns) S1 to S25 described later on the wafer W. Project. The light receiving optical system RL collects the detection light reflected by the wafer W and forms aerial images of the light transmitting slits S1 to S25 on the light receiving slits R1 to R25 described later.

  Detection light emitted from a light source (not shown) that supplies detection light to the light transmission optical system SL enters an incident end (not shown) of the light guide fiber 10 via a collimator lens or the like (not shown). To do. As shown in FIG. 1, the detection light propagated through the light guide fiber 10 exits from the exit end 10 a of the light guide fiber 10, passes through the condenser lens 11, and enters the light transmission slit prism 12.

  FIG. 2 is a diagram illustrating the configuration of the exit surface 12 a of the light transmission slit prism 12. The exit surface 12 a of the light-sending slit prism 12 is disposed at a position optically conjugate with the wafer W. Further, as shown in FIG. 2, a plurality of light transmission slits S1 to S25 are arranged on the exit surface 12a. The detection light that has passed through the plurality of light transmission slits S <b> 1 to S <b> 25 on the exit surface 12 a is reflected by the bending mirror 16, passes through the second objective lens 17, and is reflected by the bending mirror 18. The detection light reflected by the bending mirror 18 is reflected by the oscillating mirror 21 disposed so as to be positioned near the focal plane on the pupil side of the first objective lens 23 described later. The oscillating mirror 21 is configured to be able to vibrate in the direction of the arrow in the figure. It functions as a scanning means for scanning.

  The detection light reflected by the oscillating mirror 21 passes through the first objective lens 23 and enters a square prism-shaped rhomboid prism 24 having a rhombic cross section. The detection light transmitted through the entrance surface of the rhomboid prism 24 is sequentially reflected by a pair of reflection surfaces parallel to each other, and exits from an exit surface parallel to the entrance surface. The detection light that has passed through the light transmission optical system SL by passing through the rhombus prism 24 is incident on the wafer W from an oblique direction.

  FIG. 3 is a diagram illustrating images T1 to T25 of the light transmission slits S1 to S25 formed when the detection light that has passed through the plurality of light transmission slits S1 to S25 on the emission surface 12a is irradiated on the wafer W. In addition, the area | region A shown with the broken-line part in a figure is an exposure area | region.

  The detection light reflected by the wafer W enters the rhomboid prism 25 that constitutes the light receiving optical system RL. The rhomboid prism 25 is a quadrangular prism having a rhombic cross section, similar to the rhombus prism 24. Therefore, the detection light that has passed through the incident surface of the rhomboid prism 25 is sequentially reflected by a pair of reflecting surfaces parallel to each other, and then passes through an exit surface parallel to the incident surface and exits from the rhombus prism 25.

  The detection light emitted from the rhombus prism 25 passes through the first objective lens 26 and the second objective lens 31, is reflected by the bending mirror 33, and enters the light receiving slit prism 35. FIG. 4 is a diagram illustrating the configuration of the incident surface 35 a of the light receiving slit prism 35. The incident surface 35a of the light receiving slit prism 35 is disposed at a position optically conjugate with the wafer W. Further, as shown in FIG. 4, light receiving slits R1 to R25 corresponding to the plurality of light transmitting slits S1 to S25 formed on the exit surface 12a of the light transmitting slit prism 12 are arranged on the incident surface 35a. . On the light receiving slits R1 to R25, the aerial images of the corresponding light transmitting slits S1 to S25 are formed. Further, in order to suppress the variation in the amount of light between the light transmitting slits S1 to S25, the length of the light receiving slits R1 to R25 in the longitudinal direction is set shorter than the length of the light transmitting slits S1 to S25 in the longitudinal direction. Further, the width of the light receiving slits R1 to R25 in the short direction is narrower than the width of the light transmitting slits S1 to S25 in the short direction. That is, it is narrower than the width of the aerial image of the light transmission slits S1 to S25 formed on the light receiving slits R1 to R25.

  The detection light that has passed through the light receiving slit prism 35 passes through the relay lenses 36a and 36b, passes through the light receiving optical system RL, and enters the light receiving sensor (photoelectric conversion means) 38. The light receiving sensor 38 photoelectrically converts detection light through the light receiving slits R1 to R25. FIG. 5 is a diagram showing a configuration of the light receiving sensor 38. As shown in FIG. 5, light receiving elements RS1 to RS25 are arranged on the light receiving surface of the light receiving sensor 38 corresponding to the light receiving slits R1 to R25, and each of the light receiving elements RS1 to RS25 is each received by the light receiving slits R1 to R25. The detection light that has passed through is received. Photoelectric conversion outputs from the light receiving elements RS <b> 1 to RS <b> 25 of the light receiving sensor 38 change with the vibration of the vibrating mirror 21. A control unit (light intensity distribution calculating means) (not shown) obtains the light intensity distribution of the aerial image of the light transmission slits S1 to S25 based on the photoelectric conversion outputs from the light receiving elements RS1 to RS25, and based on the light intensity distribution. The position of at least one point on the wafer W is detected. The control unit calculates a correction amount in the Z direction of the Z stage ZS based on the detection result, and drives the Z stage ZS to be at the best focus position based on the calculation result.

  According to the surface position detection apparatus 2 according to the first embodiment, the structure on the wafer W is detected in order to detect the position of at least one point of the wafer W based on the light intensity distribution of the aerial image of the light transmission slits S1 to S25. The surface position of the wafer W can be accurately detected without being affected by the above. That is, even when the detection light is incident on the resist without reflecting the surface of the resist coated on the wafer W surface, the position in the Z direction of the wafer W is accurately detected without causing a measurement error. can do.

  In the oblique incidence type surface position detection device, the incident angle of the detection light incident on the wafer is increased (for example, 84 degrees), thereby being applied onto the wafer W surface as shown by an arrow A1 in FIG. The detection light is reflected on the surface of the resist 20. However, as shown by an arrow A2 in FIG. 6, a part of the detection light is incident on the inside of the resist 20, passes through the resist 20, and is reflected by the surface of the wafer W. Therefore, in the conventional surface position detection apparatus, since the size of the light transmission slit is finite, a measurement error may occur due to the state and structure of the surface of the wafer W.

  That is, in the conventional surface position detection device, the shape of the light transmission slit and the light reception slit, particularly the slit width, is substantially the same, and only the amount of the detection light passing through the light transmission slit and the light reception slit is detected. The positional relationship between the image of the light transmission slit S and the light receiving slit R in the conventional surface position detection device (when the positional deviation of the wafer W in the Z direction is −Z, −Z / 2, 0, + Z / 2, + Z) is shown. 7 shows. With the center of the position of the image of the light transmission slit S with respect to the light receiving slit R shown in FIG. 7, the image of the light transmission slit S vibrates in the direction of the arrow in the figure along with the vibration of the vibration mirror. FIG. 8 is a graph showing a change in the amount of detection light accompanying the vibration of the vibrating mirror when each of the positional deviations −Z, −Z / 2, 0, + Z / 2, and + Z occurs. FIG. 9 is a graph showing changes when the positional deviation in the Z direction of the wafer W is plotted on the horizontal axis, and the difference I between the light quantity I1 at the detection point P1 and the light quantity I2 at the detection point P2 shown in FIG. . Here, when the detection light reflected by the surface of the resist 20 and the detection light incident on the resist 20 and reflected by the surface of the wafer W as described above are simultaneously detected, the waveform shown in FIG. 8 changes. The graph shown in FIG. 9 also changes. Therefore, the conventional surface position detection apparatus has a problem that a measurement error occurs and the position of the wafer W in the Z direction cannot be measured accurately.

  In the surface position detection device 2 according to this embodiment, the width of the light receiving slit in the short direction is narrower than the width of the light transmitting slit in the short direction, that is, the width of the light receiving slit in the short direction is extremely narrow. The light intensity distribution of the aerial image of the light transmission slit is detected. The positional relationship between the aerial image of the light transmission slit S1 and the light receiving slit R1 in the surface position detection apparatus 2 according to this embodiment (the positional deviation of the wafer W in the Z direction is −Z, −Z / 2, 0, + Z / 2, FIG. 10 shows the case of + Z. The spatial image of the light transmission slit S1 vibrates in the direction of the arrow in the drawing along with the vibration of the vibration mirror 21, with the position of the spatial image of the light transmission slit S1 relative to the light receiving slit R1 shown in FIG. FIG. 11 shows the space of the light transmission slit S1 when the oscillating mirror 21 scans in one direction (outward scan) when each of the positional deviations -Z, -Z / 2, 0, + Z / 2, + Z occurs. 12 is a graph showing the light intensity distribution of an image, and P1 and P2 in FIG. 11 represent points at which the scanning direction of the oscillating mirror 21 is switched (hereinafter referred to as direction change points). 12, the positional deviation in the Z direction of the wafer W is taken on the horizontal axis, and the position P of the image of the light transmission slit with respect to the light receiving slit between the direction turning point P1 and the direction turning point P2 shown in FIG. It is a graph which shows the change of time.

  Here, the amplitude of the oscillating mirror 21 is about ± 2Z, and the photoelectric conversion output by the light receiving sensor 38 at the time of forward scanning is sampled in time series in synchronization with the vibration of the oscillating mirror 21, and the signal waveform of the photoelectric conversion output is The surface position of the wafer W is detected by performing a predetermined algorithm process. The surface position of the wafer W may be detected by performing a predetermined algorithm process on the signal waveform obtained during the backward scan and performing an averaging process.

  Next, another photoelectric detection method using the surface position detection apparatus 2 according to this embodiment will be described. FIG. 13 shows the light intensity distribution of the aerial image of the light-sending slit S1 when the oscillating mirror 21 reciprocally scans when the positional deviations −Z, −Z / 2, 0, + Z / 2, and + Z occur. It is a graph to show. FIG. 14 shows the distance D1 between the turning points of the maximum light quantity centered on the turning point P1 shown in FIG. 13 and the maximum centering on the turning point P2, with the positional deviation in the Z direction of the wafer W as the horizontal axis. It is a graph which shows a change when the difference D (D1-D2) with the space | interval D2 between the turning points of light quantity is made into the vertical axis | shaft. Here, the amplitude of the oscillating mirror 21 is set to about ± 2Z, the photoelectric conversion output by the light receiving sensor 38 is sampled in time series in synchronization with the oscillation of the oscillating mirror 21, and a predetermined algorithm process is performed on the signal waveform of the photoelectric conversion output. To detect the surface position of the wafer W.

  By performing such processing, even when the detection light reflected by the resist surface and the detection light incident on the resist and reflected by the surface of the wafer W are simultaneously detected, a measurement error occurs. In addition, the position of the wafer W in the Z direction can be accurately detected. Specific examples will be described below.

  For example, a photoelectric detection method in the case where an image of the light transmission slit S1 is formed on the wafer surface coated with a resist will be described. FIG. 15 is a graph showing the light intensity distribution of the aerial image of the light transmission slit S1 when the detection light that has passed through the light transmission slit S1 reaches the wafer W surface coated with the resist. The light intensity distribution of the aerial image of the light transmission slit S1 formed by the detection light reflected by the wafer W surface coated with the resist is reflected by the wafer W surface not coated with the resist as shown in the graph of FIG. It changes with respect to the light intensity distribution of the aerial image formed by the detected light. That is, the light intensity distribution of the aerial image formed by the detection light reflected by the resist surface overlaps the light intensity distribution of the aerial image formed by the detection light incident on the resist and reflected by the resist back surface (wafer W surface). As a whole, it becomes asymmetric, and particularly the edge portion is deformed. As shown in the graph of FIG. 17, by separating the detected signal component B1 into two signal components B2 and B3 having different phases using a signal waveform algorithm, a space formed by detection light reflected by the resist surface The position of the signal component B2 indicating the light intensity distribution of the image is measured, and the surface position of the wafer W is detected. That is, the shape of the signal component B2 is used as the original signal waveform shape, and an algorithm process generally called blind deconvolution is performed to obtain the position of the signal component B2 having a high signal intensity, for example, and based on the position of the signal component B2. Then, the surface position of the wafer W is detected (hereinafter referred to as algorithm processing 1).

  In addition, for example, a light transmission slit is formed between a region having a high reflectance (hereinafter referred to as a high reflectance region) and a region having a low reflectance (hereinafter referred to as a low reflectance region) on the wafer W surface, which is a lower layer of the resist layer. A method of photoelectric detection when the image of S1 is formed will be described. In the surface position detection apparatus 2 according to this embodiment, since the light transmission optical system SL includes the vibration mirror 21, as shown in FIG. 18, the light receiving slit R1 and the wafer W surface (the high reflection region C1 and the low reflection region). The relative position to C2) is fixed. Therefore, the relative position between the light receiving slit R1 and the wafer W surface is not changed by the scanning of the light transmission slit S1 due to the vibration of the vibration mirror 21. As shown in FIG. 19, since the light intensity distribution F of the detected spatial image of the light transmission slit S1 changes only in the reflectance of the detection light reflected by the low reflection region C2, the high reflection region C1 is measured. As compared with, only the light intensity of the light intensity distribution E of the aerial image of the light transmission slit S1 is reduced, and there is no change in the light intensity distribution shape, so that no measurement error occurs.

  For example, as shown in FIG. 20, when the high reflection region C3 and the low reflection region C4 are mixed on the wafer W surface below the resist layer, the relative position between the light receiving slit R1 and the wafer W surface is as described above. Only the reflectance of the detection light reflected by the wafer W surface does not change. However, when the surface position of the wafer W is defocused, the detection light reflected by the surface of the wafer W is affected by diffraction, which may affect the light intensity distribution of the aerial image of the light transmission slit S1. There is. That is, as shown in FIG. 21, the detected light intensity distribution H of the aerial image of the light transmission slit S1 is that of the light transmission slit S1 formed by the detection light reflected by the wafer W surface not coated with the resist. Unlike the light intensity distribution G of the aerial image, there is a possibility of having noise.

  In this case, the measurement error component can be eliminated if the measurement can be performed without the influence of noise and dents using the signal waveform processing algorithm. For example, an ideal signal waveform shape formed by detection light reflected by a reference wafer W surface to which a resist is not applied is used as an original signal waveform shape to eliminate noise, thereby performing processing for eliminating the noise. The surface position can be accurately detected (a kind of blind deconvolution, hereinafter referred to as algorithm processing 2).

  For example, as shown in FIG. 22, when there is a thin dark line on the wafer W surface (a thin low-reflection region C5 on the wafer W surface), the relative position between the light receiving slit R1 and the wafer W surface does not change as described above. Only the reflectance of the detection light reflected by the wafer W surface changes. Therefore, as shown in FIG. 23, the detected light intensity distribution K of the aerial image of the light transmission slit S1 is the aerial image of the light transmission slit S1 formed by the detection light reflected by the highly reflective wafer W surface. In comparison with the light intensity distribution J, only the amount of light is reduced, and no deformation of the light intensity distribution shape occurs, so that no measurement error occurs.

  In the surface position detection apparatus 2 according to this embodiment, the light transmission optical system SL includes the vibration mirror 21, but the light reception optical system RL is between the first objective lens 26 and the second objective lens 31. A vibration mirror (hereinafter referred to as vibration mirror 21 ′) may be provided in the optical path. In this case, it is preferable to arrange the vibrating mirror 21 ′ in the vicinity of the focal plane on the pupil side of the first objective lens 26. In this case, the relative position between the light transmission slit S1 and the wafer W surface is not changed by the scanning of the light transmission slit S1 with respect to the light receiving slit R1 due to the vibration of the vibration mirror 21 '. FIG. 25 shows a graph of the light intensity distribution of the aerial image of the light transmission slit S1 when the relative position between the light transmission slit S1 and the wafer W surface (the high reflection region C1 and the low reflection region C2) is as shown in FIG. . As shown in FIG. 25, the light intensity distribution of the aerial image of the light transmission slit S1 is ideally formed by the detection light reflected by the reference wafer W surface on which the resist is not applied as shown in the graph of FIG. With respect to the light intensity distribution of a typical aerial image, the upper shape is slanted and the center is asymmetric. In this case, for example, by performing high-pass filter processing as a general algorithm processing method, measurement errors can be suppressed and the surface position of the wafer W can be accurately detected. In addition, measurement error can be further suppressed by using the algorithm processing 1.

  In addition, the light receiving optical system RL includes a vibrating mirror 21 ′, and for example, as shown in FIG. 26, an image of the light transmission slit S1 is formed on the wafer W surface where the high reflection region C3 and the low reflection region C4 are mixed. A method of photoelectric detection will be described. As shown in FIG. 27, the light intensity distribution of the aerial image of the light transmission slit S1 is ideally formed by the detection light reflected by the reference wafer W surface to which the resist is not applied as shown in the graph of FIG. With respect to the light intensity distribution of a typical aerial image, it has a noise-like shape and is asymmetric as a whole, resulting in measurement errors. However, in the surface position detection apparatus according to this embodiment, the surface position of the wafer W can be accurately detected by performing the algorithm process 2.

  A photoelectric detection method in the case where the light receiving optical system RL includes the vibrating mirror 21 ′ and there is a thin dark line (low reflection region C5) on the wafer W surface as shown in FIG. 28 will be described. As shown in FIG. 29, the light intensity distribution of the aerial image of the light transmission slit S1 is ideally formed by the detection light reflected by the reference wafer W surface on which the resist is not applied as shown in the graph of FIG. The light intensity distribution of a typical aerial image has a shape that is partially recessed. In this case, the surface position of the wafer W can be accurately detected by performing the algorithm process 2.

  The case where the aerial image of the light transmission slit S1 is formed in the light receiving slit R1 has been described above. However, the wafer is formed in the same manner when the aerial image of the light transmission slits S2 to S25 is formed in the light receiving slit R2 to R25. The surface position of W can be detected.

  In this case, the light transmission slits S1 to S25 and the wafer W surface satisfy the Scheinproof relationship with respect to the combined optical system of the first and second objective lenses 23 and 17 in the light transmission optical system SL. It is preferable that the wafer W surface and the light receiving slits R1 to R25 satisfy the Scheinproof relationship with respect to the combined optical system of the first and second objective lenses 26 and 31 in the light receiving optical system RL.

  According to the projection exposure apparatus of this embodiment, the position of the wafer W in the Z direction can be accurately detected by the above-described photoelectric detection method, so that the pattern of the reticle R can be accurately formed on the wafer W surface. Can be exposed.

  In the projection exposure apparatus according to the above-described embodiment, the vibrating mirror is used as the scanning unit. However, the scanning exposure unit is not limited to the vibrating mirror as long as the scanning unit has the same performance as the vibrating mirror.

  Hereinafter, in the above-described embodiment, a supplementary description will be given of processing when obtaining an aerial image by sampling the photoelectric conversion output in time series in synchronization with the driving of the vibrating mirror.

  When scanning of the light transmission slits S1 to S25 using the oscillating mirror 21 is performed at a constant speed with respect to time, sampling may be performed at equal time intervals and the time may be converted into the position of slit scanning. When the vibration mirror 21 that converts rotational motion into translational motion is used, it is non-constant with respect to time, and the periodic motion is the same as in the case where the scanning of the light transmission slit is simple vibration.

In such a case, after obtaining sampling signals at sufficiently small equal time intervals, the time may be converted into the slit position coordinate system by the following calculation process.
P = A · sin [2π / T (t−t0)]
However,
P: Scanning position A: Conversion coefficient T: Scanning cycle t: Time t0: Reference vibration center time.

  After that, for example, if interpolation processing is performed in a signal processing system, data with non-uniform sampling intervals can be converted into data with uniform intervals with high accuracy, and the processing of this embodiment is performed using this data. Can do.

  Further, when sampling in time series, it is possible to detect signals at unequal time intervals so as to be at equal intervals with respect to the actual scanning position.

  As described above, in this embodiment, even if the slit scanning is a periodic motion, measurement can be performed without being affected by the movement.

  In the above-described embodiment, since the width of the light receiving slit is extremely narrow, if a general SPD (silicon photodiode) or the like is used as the light receiving element, the amount of received light may be insufficient. In such a case, as the light receiving elements RS1 to RS25 of the light receiving sensor 38, a required number of photomultiplier tubes, hybrid photo detectors, channel photomultiplier tubes, etc., which are high sensitivity detectors, may be bundled in an array. .

  Next, a projection exposure apparatus according to a second embodiment of the present invention will be described with reference to the drawings. Note that the projection exposure apparatus according to the second embodiment includes the light receiving slits R1 to R25 and the light receiving sensor 38 (light receiving elements RS1 to RS1) that constitute the surface position detection apparatus 2 included in the projection exposure apparatus according to the first embodiment. RS25) is not provided, but a light receiving sensor 40 (see FIG. 31) described later is provided. Further, the surface position detection apparatus provided in the projection exposure apparatus according to the second embodiment includes a direct-view prism 42 (see FIG. 30) that divides the detection light.

  Except for the points described above, the configuration of the projection exposure apparatus according to the second embodiment is the same as the configuration of the projection exposure apparatus according to the first embodiment. Therefore, in the description of the second embodiment, a detailed description of the same configuration as the configuration of the projection exposure apparatus according to the first embodiment is omitted. In the description of the projection exposure apparatus according to the second embodiment, the same reference numerals as those used in the first embodiment are assigned to the same components as those of the projection exposure apparatus according to the first embodiment. A description will be given.

  The surface position detection apparatus according to this embodiment includes a light source (not shown) that supplies white light including a long wavelength range from a short wavelength range. Further, in the surface position detection apparatus according to this embodiment, as shown in FIG. 30, a direct-view prism 42 as a spectroscopic means is disposed in the optical path between the relay lenses 36a and 36b. The direct-view prism 42 is preferably disposed at the pupil position of the relay optical system that constitutes the relay lenses 36a and 36b. The direct-view prism 42 splits the incident detection light (white light) into light having a shorter wavelength tendency (detection light in the first wavelength range) L1 and light having a longer wavelength tendency (detection light in the second wavelength range) L2. To do. The direct-view prism 42 forms detection light having a light beam cross section that is twice or more the light beam cross section of the detection light that has passed through the light receiving slits R1 to R25 (predetermined regions on the imaging surface of the light receiving optical system RL). .

  FIG. 31 is a diagram showing the configuration of the light receiving sensor (detecting means) 40. As shown in FIG. 31, light receiving elements 51a, 51b to 75a, 75b are provided. The light receiving elements 51a and 51b are arranged corresponding to the light receiving slit R1 on the incident surface (slit member) 35a of the light receiving slit prism 35, receive the detection light that has passed through the light receiving slit R1, and perform photoelectric conversion. Light L1 having a short wavelength tendency out of the detection light that passes through the light receiving slit (light transmitting portion) R1 and is split by the direct-view prism 42 enters the light receiving element 51a, and receives the light receiving element (first photoelectric converter, first detection). Means) 51a receives and detects light L1 having a short wavelength tendency. Further, light L2 having a long wavelength tendency out of the detection light that passes through the light receiving slit (light transmitting portion) R1 and is split by the direct-view prism 42 enters the light receiving element 51b, and receives the light receiving element (second photoelectric converter, second photoelectric converter). (2 detecting means) 51b receives and detects the light L2 having a long wavelength tendency. That is, the light receiving elements 51a and 51b simultaneously detect the light L1 having a short wavelength tendency and the light L2 having a long wavelength tendency, which are split by the direct viewing prism 42 through the light receiving slit R1.

  A control unit (not shown) obtains the light intensity distribution of the aerial image of the light transmission slit S1 based on the photoelectric conversion output from the light receiving elements 51a and 51b, and detects the position of the wafer W based on the light intensity distribution. For example, as shown in FIG. 32, the light intensity distribution of the aerial image of the light transmission slit S1 formed by light having a short wavelength tendency and the light intensity distribution of the aerial image of the light transmission slit S1 formed by light having a long wavelength tendency. If there is a measurement error, the measurement error is caused by the difference in wavelength range. Therefore, measurement accuracy can be improved by taking the average of each light intensity distribution. Further, when a measurement deviation occurs in proportion to the wavelength due to the state of the surface of the wafer W or the like, an offset process may be added to the whole from the difference in measurement results.

  Similarly, the light receiving elements 52a, 52b to 75a, 75b are arranged corresponding to the respective light receiving slits R2 to R25, receive the detection light that has passed through the light receiving slits R2 to R25, and perform photoelectric conversion. The light receiving elements (first photoelectric converters, first detection means) 52a to 75a pass through the light receiving slits (light transmitting portions) R2 to R25 and are light having a short wavelength tendency among the detection lights dispersed by the direct viewing prism 42. L1 is received and detected. In addition, the light receiving elements (second photoelectric converter, second detection means) 52b to 75b tend to have a long wavelength in the detection light that passes through the light receiving slits (light transmitting portions) R2 to R25 and is split by the direct-view prism 42. The light L2 is received and detected. A control unit (not shown) processes the photoelectric conversion outputs from the light receiving elements 52a to 75a and 52b to 75b in the same manner as the photoelectric conversion outputs from the light receiving elements 51a and 51b.

  According to the surface position detection apparatus according to the second embodiment, the light receiving elements 51a to 75a that detect the light L1 having the short wavelength tendency that is split by the direct-view prism 42, and the light receiving element that detects the light L2 that has the long wavelength tendency. Since the position of at least one point of the wafer W as the test surface is detected based on the detection results of 51b to 75b, it is possible to prevent the occurrence of detection error due to the difference in wavelength range, and the surface position of the wafer W can be accurately determined. Can be detected.

  Further, since the detection light having a light beam cross section more than twice the light beam cross section of the detection light that has passed through the light receiving slits R1 to R25 by the direct viewing prism 42 can be formed and dispersed, the light passes through the light receiving slits R1 to R25. The light L1 having the short wavelength tendency and the light L2 having the long wavelength tendency can be simultaneously detected by the adjacent light receiving elements 51a to 75a and 51b to 75b.

  The surface position detection apparatus according to the second embodiment includes the direct-view prism 42 as the spectroscopic means, but may include a diffraction grating, a prism, or the like as the spectroscopic means. The direct-view prism 42 is disposed in the optical path between the relay lenses 36 a and 36 b, but in the optical path between the incident surface 35 a (the light receiving slits R 1 to R 25) of the light receiving slit prism 35 and the light receiving sensor 40. It only has to be arranged.

  In the projection exposure apparatus according to each of the above-described embodiments, a micropatterning device is exposed by exposing a photosensitive substrate (plate) with a transfer pattern formed by a reticle (mask) using a projection optical system (exposure process). (Semiconductor elements, imaging elements, liquid crystal display elements, thin film magnetic heads, etc.) can be manufactured. Hereinafter, an example of a technique for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a plate or the like as a photosensitive substrate using the projection exposure apparatus according to each of the above-described embodiments will be described with reference to FIG. This will be described with reference to the flowchart of FIG.

  First, in step S301 of FIG. 33, a metal film is deposited on one lot of plates. In the next step S302, a photoresist is applied on the metal film on one lot of plates. Thereafter, in step S303, the projection exposure apparatus according to each of the above-described embodiments is used to adjust the focus position on the plate by the surface position detection apparatus included in the projection exposure apparatus, and the mask pattern image is projected optically. Through the system, exposure and transfer are sequentially performed on each shot area on the plate of one lot. Thereafter, in step S304, the photoresist on the one lot of plates is developed, and in step S305, the resist pattern is etched on the one lot of plates to correspond to the mask pattern. A circuit pattern is formed in each shot area on each plate.

  Thereafter, an upper layer circuit pattern is formed, and the plate is cut into a plurality of devices to manufacture devices such as semiconductor elements. According to the semiconductor device manufacturing method described above, since exposure is performed using the scanning projection exposure apparatus according to each of the embodiments described above, exposure can be performed with high accuracy and a good semiconductor device can be obtained. Can do. In steps S301 to S305, a metal is vapor-deposited on the plate, a resist is applied on the metal film, and exposure, development and etching processes are performed. Prior to these processes, the process is performed on the plate. It is needless to say that after forming a silicon oxide film, a resist may be applied on the silicon oxide film, and steps such as exposure, development, and etching may be performed.

  In the projection exposure apparatus according to each of the above-described embodiments, a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). it can. Hereinafter, an example of the technique at this time will be described with reference to the flowchart of FIG. First, in FIG. 34, in the pattern formation step S401, the projection exposure apparatus according to each of the above embodiments is used to transfer and expose the mask pattern onto a photosensitive substrate (such as a glass substrate coated with a resist). A lithography process is performed. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate undergoes steps such as a developing step, an etching step, and a resist stripping step, whereby a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming step S402.

  Next, in the color filter forming step S402, a large number of groups of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three of R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning line direction. Then, after the color filter formation step S402, a cell assembly step S403 is executed. In the cell assembly step S403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step S401, the color filter obtained in the color filter formation step S402, and the like. In the cell assembly step S403, for example, liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern formation step S401 and the color filter obtained in the color filter formation step S402, and a liquid crystal panel (liquid crystal cell ).

  Thereafter, in a module assembly step S404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display element, since the exposure is performed using the projection exposure apparatus according to each of the above-described embodiments, the exposure can be performed with high accuracy and a good liquid crystal display element is obtained. be able to.

It is a figure which shows the structure of the exposure apparatus concerning 1st Embodiment. It is a figure which shows the structure of the output surface of the light transmission slit prism concerning 1st Embodiment. It is a figure for demonstrating the image of the light transmission slit formed on the wafer surface concerning 1st Embodiment. It is a figure which shows the structure of the entrance plane of the light-receiving slit prism concerning 1st Embodiment. It is a figure which shows the structure of the light reception sensor concerning 1st Embodiment. It is a figure for demonstrating the factor of a measurement error. It is a figure which shows the relative positional relationship of the conventional light transmission slit and a light-receiving slit. It is a graph which shows the light quantity change of the detection light accompanying the vibration of a vibration mirror in the conventional surface position detection apparatus. It is a graph which shows the relationship between the focus position of a wafer, and light quantity change. It is a figure which shows the relative positional relationship of the light transmission slit and light reception slit concerning 1st Embodiment. It is a graph which shows the light intensity distribution of the aerial image accompanying the vibration of a vibration mirror in the surface position detection apparatus concerning 1st Embodiment. It is a graph which shows the relationship between the focus position of a wafer, and the position of a light transmission slit. It is a graph which shows the light intensity distribution of the aerial image accompanying the vibration of a vibration mirror in the surface position detection apparatus concerning 1st Embodiment. It is a graph which shows the relationship between the focus position of a wafer, and the difference of the space | interval between turning points. It is a graph which shows the light intensity distribution of the aerial image accompanying the vibration of a vibration mirror in the surface position detection apparatus concerning 1st Embodiment. It is a graph which shows the light intensity distribution of an aerial image. It is a graph which shows the light intensity distribution of an aerial image. It is a figure which shows the relative positional relationship of a light-receiving slit and a wafer. It is a graph which shows the light intensity distribution of an aerial image. It is a figure which shows the relative positional relationship of a light-receiving slit and a wafer. It is a graph which shows the light intensity distribution of an aerial image. It is a figure which shows the relative positional relationship of a light-receiving slit and a wafer. It is a graph which shows the light intensity distribution of an aerial image. It is a figure which shows the relative positional relationship of a light transmission slit and a wafer. It is a graph which shows the light intensity distribution of an aerial image. It is a figure which shows the relative positional relationship of a light transmission slit and a wafer. It is a graph which shows the light intensity distribution of an aerial image. It is a figure which shows the relative positional relationship of a light transmission slit and a wafer. It is a graph which shows the light intensity distribution of an aerial image. It is a figure which shows the structure of the direct-view prism concerning 2nd Embodiment. It is a figure which shows the structure of the light reception sensor concerning 2nd Embodiment. It is a graph which shows the light intensity distribution of the aerial image accompanying the vibration of a vibration mirror in the surface position detection apparatus concerning 2nd Embodiment. It is a flowchart which shows the manufacturing method of the semiconductor device as a microdevice concerning embodiment of this invention. It is a flowchart which shows the manufacturing method of the liquid crystal display element as a microdevice concerning embodiment of this invention.

Explanation of symbols

  IL ... illumination optical system, PL ... projection optical system, R ... reticle, W ... wafer, RST ... reticle stage, WH ... wafer holder, WT ... wafer table, ZS ... Z stage, XS ... X stage, YS ... Y stage, 2 ... Surface position detection device, SL ... Light transmission optical system, RL ... Light reception optical system, 12 ... Light transmission slit prism, 16, 18, 33 ... Bending mirror, 23,26 ... First objective lens, 17, 31 ... Second Objective lens, 21 ... vibrating mirror, 24, 25 ... diamond prism, 35 ... light receiving slit prism, 36a, 36b ... relay lens, 38, 40 ... light receiving sensor, 42 ... direct view prism.

Claims (8)

The predetermined light via the predetermined pattern of the pattern member on which a predetermined pattern is formed sending optical system for irradiating obliquely to the test surface, and on the basis of the light reflected by the test surface An imaging optical system including a light receiving optical system for forming a spatial image of the pattern of
A light receiving slit member disposed at a position where the aerial image is formed and having a light receiving slit through which the light can pass;
Scanning means for relatively scanning the aerial image and the light receiving slit in a predetermined direction;
Photoelectric conversion means for photoelectrically converting the light that has passed through the light receiving slit ;
Detecting means for obtaining a light intensity distribution of the aerial image formed on the light receiving slit based on a conversion result of the photoelectric converting means, and detecting a surface position of the test surface based on the light intensity distribution ; With
The surface position detecting device according to claim 1, wherein a width of the light receiving slit in the predetermined direction is narrower than a width of the aerial image in the predetermined direction. The imaging optical system forms the slit-shaped aerial image;
The width of the light receiving slit in the short direction is set to be narrower than the width of the aerial image in the short direction,
It said scanning means, and said light receiving slit and the aerial image, the surface position detecting apparatus according to claim 1, characterized in that for relatively scanning the longitudinal direction different from the direction of the aerial image and the receiving slit.   3. The scanning unit includes a mirror element that is provided in the light transmission optical system or the light receiving optical system and reflects the light while oscillating in a direction corresponding to the predetermined direction. The surface position detection apparatus described in 1. The light transmission optical system is provided so that the surface of the pattern member on which the light transmission pattern is formed and the test surface satisfy a Scheinproof relationship,
The light receiving optical system, any of claims 1 to 3, characterized in that the surface on which the receiving slit is provided within the receiving slit member and said test surface is provided so as to satisfy the Scheimpflug relationship surface position detecting apparatus according to an item or. A spatial image forming step of irradiating the test surface with light through the predetermined pattern from an oblique direction, and forming a spatial image of the predetermined pattern based on the light reflected by the test surface;
A light-receiving slit arranged at a position where the aerial image is formed and through which the light can pass, and a scanning step of relatively scanning the aerial image in a predetermined direction;
A photoelectric conversion step of photoelectrically converting the light that has passed through the light receiving slit ;
Based on the conversion result of the photoelectric conversion step, obtaining a light intensity distribution of the aerial image formed on the light receiving slit , and detecting a surface position of the test surface based on the light intensity distribution ;
Including
The surface position detection method according to claim 1, wherein the width of the light receiving slit in the predetermined direction is narrower than the width of the aerial image in the predetermined direction. In the aerial image forming step, the slit-shaped aerial image is formed,
The width of the light receiving slit in the short direction is set to be narrower than the width of the aerial image in the short direction,
6. The surface position detection method according to claim 5 , wherein in the scanning step, the aerial image and the light receiving slit are scanned relatively in a direction different from a longitudinal direction of the aerial image and the light receiving slit . An exposure apparatus that irradiates a photosensitive substrate with exposure light via a projection optical system,
An exposure apparatus comprising the surface position detection device according to any one of claims 1 to 4 , which detects a surface position of the photosensitive substrate with respect to the projection optical system. An exposure step of exposing a photosensitive substrate using the exposure apparatus according to claim 7 ;
A developing step of developing the photosensitive substrate exposed by the exposing step;
A device manufacturing method comprising:

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