TW201734653A - Detection device, exposure device, and method of manufacturing devices - Google Patents

Abstract

A detection device having a projection system 22 that projects a light from an oblique direction against the normal line of a surface of an object and a light receiving system 23 that receives a reflected light 20, and that detects a surface position based on data obtained by the light receiving system 23, the reflected light 20 including a front/back reflected light, the light receiving system 23 including a polarized light separation unit 15 that separates the reflected light into a first/second polarized light, and detection units 16, 17 that detect the first/second polarized light, the projection system 22 or the light receiving system 23 being configured such that the first/second polarized light of the back reflected light, which are obtained by the detection units, are equal, and including a calculating unit that calculates the position based on differential data between data showing the first/second polarized light.

Description

Detection device, exposure device, and method of manufacturing the same

The present invention relates to a detecting device, an exposure device, and a method of manufacturing the device.

In a photolithography process which is one of manufacturing methods for a semiconductor device or the like, an exposure device is used, and an exposure device transfers an original pattern onto an exposed region on a substrate via a projection optical system. In order to correctly transfer the pattern, it is necessary to correctly detect the height of the surface (exposure area) of the substrate in the optical axis direction of the projection optical system. Therefore, the exposure apparatus includes a detection system (detection means) that detects the height of the surface of the substrate.

The detection system includes a projection system that projects the detection light onto a surface of the substrate, and a light receiving system that receives the reflected light from the substrate. If a transparent substrate (for example, glass) that transmits the detection light is used as the substrate, the reflected light from the surface of the substrate and the reflected light from the rear surface of the substrate overlap each other, and thus the detection accuracy may be deteriorated. This inconvenience has accompanied the demand for lighter and thinner substrates in recent years. And it became obvious. Japanese Patent Publication No. 2004-273828 discloses a method of determining reflected light from a surface from the above two kinds of reflected light. Japanese Patent Publication No. 2010-271603 discloses an apparatus in which a fluid having the same refractive index as a substrate is disposed directly under the substrate so that the light receiving system does not receive reflected light from the rear surface.

However, depending on the thickness of the transparent substrate, the method disclosed in Japanese Patent Laid-Open No. 2004-273828 and the apparatus disclosed in Japanese Patent Laid-Open No. 2010-271603 may be difficult to distinguish between the two kinds of reflected light.

The present invention is used, for example, to provide a detection method that is advantageous in detecting the height of the surface of the substrate.

The present invention is a detecting device having a projection system that projects a detection light from an oblique direction with respect to a normal to a surface to be detected of an object to be detected, and a light receiving system that receives the reflection reflected by the object to be detected The light detecting means detects the position of the surface to be inspected based on the data obtained by the light receiving system, the reflected light including the surface reflected light reflected on the surface to be inspected, and transmitted through the surface to be inspected and on the rear surface of the object to be inspected The upper reflective surface reflects light, the light receiving system includes a polarized light separating unit and a detecting unit, the polarized light separating unit separates the reflected light into a first polarized light component and a second polarized light component, and the detecting unit detects the first polarized light component and a second polarized light component, the projection system or the light receiving system is configured such that the rear surface reflected light obtained by the detecting unit The first polarized light component is equal to the second polarized light component of the rear surface reflected light, and the projection system or the light receiving system includes a calculation unit that calculates the data and display based on the first polarized light component obtained by the detecting unit The difference data between the data of the two polarized light components is used to calculate the position.

Further features of the present invention will become apparent from the following description of exemplary embodiments.

1‧‧‧ original

2‧‧‧Exposure device body

3‧‧‧Lighting optical system

4‧‧‧Projection optical system

5‧‧‧Substrate

6‧‧‧Substrate holding unit

7‧‧‧ substrate table

8‧‧ ‧ mirror

9‧‧‧Laser Interferometer

10‧‧‧Light source

11‧‧‧Measurement slit

12‧‧‧Polarization unit

13‧‧‧Light projection lens

14‧‧‧Light receiving lens

15‧‧‧Polarized beam splitter

16‧‧‧ position sensor

17‧‧‧ position sensor

18‧‧‧Computation unit

19‧‧‧Detecting light

20‧‧‧ Receiving light (front surface reflected light)

21‧‧‧ Receiving light (back surface reflected light)

22‧‧‧Projection system

23‧‧‧Light receiving system

Θ‧‧‧incident angle

As‧‧‧

Ap‧‧‧ points

Bs‧‧ points

Bp‧‧ points

D‧‧‧distance

FIG. 1 is a schematic view showing a configuration of an exposure apparatus including the detecting device according to the first embodiment.

2 is a schematic view showing a path of light reflected on a surface of a substrate and a path of light reflected on a rear surface of the substrate.

Fig. 3 is a schematic view for explaining a case where the position sensor is not affected by the reflected light of the rear surface.

Figure 4 shows the light intensity distribution output by the position sensor in the case of Figure 3.

Fig. 5 is a schematic view for explaining a case where the position sensor is affected by the reflected light of the rear surface.

Fig. 6 shows the light intensity distribution output by the position sensor in the case of Fig. 5.

Fig. 7 shows the relationship between the incident angle of the detection light for the substrate and the reflectance of the p-polarized light and the reflectance of the s-polarized light.

Figure 8 shows the light intensity distribution of s-polarized light output by the position sensor when the incident angle is 78 degrees.

Figure 9 shows the light intensity distribution of p-polarized light output by the position sensor when the incident angle is 78 degrees.

Figure 10 shows the result of performing differential processing on the two output signals by the computing unit.

Fig. 11 is a schematic view showing the configuration of a detecting device according to the second embodiment.

Figure 12 shows the light intensity distribution of the s-polarized light output by the position sensor.

Figure 13 shows the light intensity distribution of p-polarized light output by the position sensor.

Figure 14 shows the result of performing differential processing on two output signals by a computing unit.

Figure 15 shows the light intensity distribution of s-polarized light output by the position sensor after the polarization state is adjusted.

Figure 16 shows the light intensity distribution of p-polarized light output by the position sensor after the polarization state is adjusted.

Figure 17 shows the result of performing differential processing on the two output signals by the calculation unit after the polarization state is adjusted.

Fig. 18 shows the relationship between the incident angle of the detection light for the substrate and the reflectance of the p-polarized light and the reflectance of the s-polarized light.

Figure 19 shows the light intensity distribution of s-polarized light output by the position sensor when the incident angle is 70 degrees.

Figure 20 shows the light intensity distribution of p-polarized light output by the position sensor when the incident angle is 70 degrees.

Figure 21 shows the light intensity distribution of s-polarized light output by the position sensor when the incident angle is 86 degrees.

Figure 22 shows the light intensity distribution of p-polarized light output by the position sensor when the incident angle is 86 degrees.

Figure 23 shows the light intensity distribution of s-polarized light output by the position sensor when the incident angle is 80 degrees.

Fig. 24 shows the light intensity distribution of p-polarized light output by the position sensor when the incident angle is 80 degrees.

Figure 25 shows the light intensity distribution before the differential processing is performed on the two signals by the calculation unit.

Fig. 26 shows the result of performing differential processing while shifting the signal of p-polarized light in the +t direction.

Fig. 27 shows the result of performing differential processing while shifting the signal of p-polarized light in the -t direction.

Hereinafter, a detailed description of a preferred embodiment of the present invention will be given with reference to the accompanying drawings and the like.

(First Embodiment)

1 is a schematic view of an exposure apparatus including a detecting device according to a first embodiment of the present invention. The exposure apparatus includes an illumination optical system 3, a projection optical system 4, and a substrate stage 7. Illumination optical system 3 illuminates the original 1, the original 1 is positioned to the exposure device by an alignment mechanism (not shown) Main body 2. The original 1 is, for example, a glass master on which a fine pattern (for example, a circuit pattern) to be exposed is drawn. The substrate stage 7 includes a substrate holding unit 6 that holds the substrate 5, and moves on an XY plane perpendicular to the optical axis (Z axis) of the projection optical system 4. The substrate 5 is, for example, a glass substrate. The pattern of the original 1 is transferred onto the exposed area on the substrate 5 via the projection optical system 4. The substrate stage 7 is movable in the Z direction as well as in the X direction and the Y direction, and is also used as a drive system for focusing the substrate 5 and the master 1. Further, the mirror 8 is placed on the substrate stage 7, and the driving in the X direction is controlled by using the laser interferometer 9. Regarding the Y direction, a configuration similar to that in the X direction (not shown) is also employed, and precise drive control on the XY plane is performed.

The detection device includes a projection system 22 and a light receiving system 23. The projection system 22 includes a light source 10, a measurement slit 11, a polarization adjustment unit 12, and a light projection lens 13. The light receiving system 23 includes a light receiving lens 14, a polarization beam splitter (polarized light separating unit) 15, position sensors (detecting units) 16 and 17, and a calculating unit 18. The light source 10 emits light having a p-polarized light component and an s-polarized light component, for example, naturally polarized light or circular polarized light, which has light having a wavelength of about 500 to 1200 nm. The detection light 19 emitted from the light source 10 is guided through a converging lens (not shown), a measurement slit 11, a polarization adjusting unit 12, and a light projection lens at an incident angle of θ with respect to a normal to the substrate (object to be detected). 13. The detection light 19 is reflected on the surface (surface to be detected) of the substrate 5, and is incident to the polarization beam splitter 15 via the light receiving lens 14 (reflection Light is used as the received light 20) and is separated into p-polarized light and s-polarized light. Subsequently, the light of the p-polarized light is guided to the position sensor 16, and the light of the s-polarized light is guided to the position sensor 17. The positional relationship between the two position sensors 16 and 17 is previously corrected by a known method (for example, measurement of a reference object), and signal outputs (data) from the two sensors are transmitted to the calculation unit. 18, and perform calculation processing. Note that in FIG. 1, although the calculation unit 18 is provided in the light receiving system 23, it may be disposed outside the light receiving system 23.

2 is a schematic view showing a path of light reflected on a surface (surface to be inspected) of the substrate 5 and a path of light reflected on a rear surface of the substrate 5, wherein light is received by the detecting means of FIG. . The received light (front surface reflected light) 20 is light reflected on the front surface of the substrate 5, and the received light (back surface reflected light) 21 is light reflected on the rear surface of the substrate 5. These two lights are directed to the light receiving system 23. The front surface reflected light 20 is separated into p-polarized light and s-polarized light by the polarization beam splitter 15, and the light of the p-polarized light is incident on the position of the point Ap on the position sensor 16, and the light of the s-polarized light is incident on The position of the point As on the position sensor 17. The focus position of the projection optical system 4 (the surface position in the normal direction of the substrate 5) is determined based on the point Ap and the point As.

However, under the influence of the surface reflected light 21 after the thickness of the substrate 5 and the incident angle, the position sensors 16 and 17 may have difficulty measuring the point Ap and the point As correctly. As shown in FIG. 2, the rear surface reflected light 21 is separated into p-polarized light and s-polarized light by the polarization beam splitter 15 like the front surface reflected light 20, and the light of the p-polarized light is incident on the position. The position of the point Bp on the sensor 16 and the light of the s-polarized light are incident on the position of the point Bs on the position sensor 17.

FIG. 3 is a diagram for explaining a case where the position sensors 16 and 17 are not affected by the back surface reflected light 21. In the case of the thickness of the substrate 5 and the incident angle θ shown in FIG. 3, the point Ap (point As) and the point Bp (point Bs) become positional relationships separated from each other by a distance "d". The outputs of the position sensors 16 and 17 correspond to the light intensity distribution formed by the measurement slits 11. Here, a slit is provided in the measurement slit 11 to simplify the description. FIG. 4 shows the light intensity distribution output by the position sensor 16 or 17 in the case of FIG. The horizontal axis represents the position on the light receiving surface of the position sensor 16 or 17, and the vertical axis represents the light intensity to be received. As shown in FIG. 4, the intensity peak of the light intensity distribution of the p-polarized light (s-polarized light) of the front surface reflected light 20 on the light receiving surface of the position sensor 16 (17) is a point Ap (As). The same applies to the back surface reflected light 21. In the case of the thickness of the substrate 5 of FIG. 3 and the incident angle θ, the light intensity distributions of the front surface reflected light 20 and the rear surface reflected light 21 do not overlap, and the position sensors 16 and 17 can detect the point Ap and the point As. Without being affected by the back surface reflected light 21.

FIG. 5 is a diagram for explaining a case where the position sensors 16 and 17 are affected by the back surface reflected light 21. The substrate 5 shown in FIG. 5 is thinner than the substrate 5 of FIG. 3 (for example, 30 μm), and the incident angle θ is the same as the incident angle θ in FIG. In this case, the distance d is narrower than the distance d in FIG. FIG. 6 shows the light intensity distribution output by the position sensor 16 or 17 in the case of FIG. As shown in FIG. 6, on the substrate 5 of FIG. In the case of the thickness and the incident angle θ, the light intensity distributions of the front surface reflected light 20 and the rear surface reflected light 21 overlap. Therefore, the position sensors 16 and 17 may have difficulty measuring the point Ap and the point As correctly due to the influence of the back surface reflected light 21.

FIG. 7 shows the relationship between the incident angle of the detection light 19 for the substrate 5 and the reflectance of the p-polarized light and the reflectance of the s-polarized light. The p-polarized light of the front surface reflected light 20 is displayed by a circle of a black outline, the s-polarized light of the front surface reflected light 20 is displayed by a black solid circle, and the p-polarized light of the rear surface reflected light 21 is displayed by a triangle of a black outline And the s-polarized light of the back surface reflected light 21 is displayed by a black solid triangle. As can be seen from FIG. 7, the reflectance of the p-polarized light of the rear surface reflected light 21 is equal to the reflectance of the s-polarized light of the rear surface reflected light 21 in the vicinity of the incident angle of 78 degrees, and the front surface reflects light. The reflectance of the s-polarized light of 20 is equal to or greater than twice the reflectance of the p-polarized light of the front-surface reflected light 20.

8 shows that when the incident angle is set to 78 degrees and the thickness of the substrate 5 is made thin as shown in FIG. 6, the light intensity of the s-polarized light (waveform data) output from the position sensor 17 is shown. distributed. The signal c ₁ outputted by the position sensor 17 is a signal obtained by combining the signal a ₁ of the s-polarized light that reflects the front surface reflected light 20 with the signal b ₁ of the s-polarized light that reflects the back surface reflected light 21 . Fig. 9 shows a light intensity distribution of p-polarized light outputted from the position sensor 16 when the incident angle is set to 78 degrees and the thickness of the substrate 5 is made thin as shown in Fig. 6. The signal c ₁ ' outputted by the position sensor 16 is obtained by combining the signal a ₁ ' of the p-polarized light that reflects the front surface reflected light 20 with the signal b ₁ ' of the p-polarized light that reflects the back surface reflected light 21. signal of.

The fact that the reflectances of the back surface reflected light 21 detected by the position sensors 16 and 17 are equal means that the polarized light signals b ₁ and b ₁ ' are equal because the light emitted from the light source 10 passes through the same route. The polarizing beam splitter 15 is reached. FIG. 10 shows the result of the differential processing between the output signal c ₁ of the position sensor 17 and the output signal c ₁ ' of the position sensor 16 by the calculation unit 18. Since the signal b ₁ and the signal b ₁ ' are equal, the signal c ₁ -c ₁ ' (differential data) remaining after the differential processing represents the signal a ₁ of the p-polarized light showing the front surface reflected light 20 and the reflected light of the front surface 20 The difference a ₁ -a ₁ ' between the signals a ₁ ' of the s-polarized light.

Since the signal a ₁ and the signal a ₁ ' are similar relations based on the reflectance differences between each other, the position of the center of gravity of each signal and its differential signal do not change. Therefore, obtaining the position of the center of gravity of the differential signal (a ₁ - a ₁ ') corresponds to obtaining the surface position of the substrate 5. (However, it is assumed that a ₁ -a ₁ '≠0.)

As described above, the detecting device (detecting method) of the present embodiment can accurately detect the surface position of the substrate 5 regardless of the thickness of the substrate 5, and according to the present embodiment, it is possible to provide detection for facilitating detection of the height of the surface of the substrate method.

(Second embodiment)

Next, a description will be given of a detecting method according to a second embodiment of the present invention. The first embodiment described above assumes an incident angle It may be set such that each of the polarized light signals of the rear surface reflected light 21 is equal. Conversely, the present embodiment can deal with the case where there is no flexibility in setting the incident angle, or the polarized light signal of the back surface reflected light 21 cannot be equal due to the occurrence of errors in components (materials), adjustment assembly, and the like. .

For example, consider a case where the incident angle is set to θ1 in FIG. In this case, the reflectance of the p-polarized light of the rear surface reflected light 21 and the reflectance of the s-polarized light of the rear surface reflected light 21 are not equal, and even in this state, even if differential processing is performed, it is impossible to accurately obtain The surface position of the substrate 5.

Therefore, in the present embodiment, the polarization adjusting unit 12 of the light receiving system 12 of the projection system 22 shown in Fig. 2 or the light receiving system 12 of the light receiving system 23 provided in the detecting device shown in Fig. 11 is used. The polarization state of the light is adjusted such that the signal of the p-polarized light and the signal of the s-polarized light output by the position sensors 16 and 17 are equal. The polarization adjusting unit 12 may be a polarization adjusting unit having an adjustment mechanism including an optical member such as a polarizing plate, a λ plate, or an anisotropic optical crystal. If it is provided in the light receiving system 23, it is preferable to use a light amount adjusting optical member such as an ND filter.

The adjustment of the polarization state of the light is performed to have a sufficient difference in the reflectance of each polarized light signal of the polarized light signal of the front surface reflected light 20, and maintain a similar relationship. In addition, before the adjustment, the front surface reflected light 20 and the rear surface reflected light 21 in the case of the incident angle θ1 The reflectance of the polarized light is recorded or measured by position sensors 16 and 17. With the above adjustment, the same differential processing as that in the first embodiment is performed, and therefore, effects similar to those in the first embodiment can be obtained.

FIG. 12 shows the light intensity distribution of the s-polarized light output by the position sensor 17 when the incident angle is set to θ1. The signal c ₂ outputted by the position sensor 17 is a signal obtained by combining the signal a ₂ of the s-polarized light that reflects the front surface reflected light 20 with the signal b ₂ of the s-polarized light that reflects the back surface reflected light 21 . FIG. 13 shows the light intensity distribution of p-polarized light output by the position sensor 16 in the same case. The signal c ₂ ' outputted by the position sensor 16 is obtained by combining the signal a ₂ ' of the p-polarized light that reflects the front surface reflected light 20 with the signal b ₂ ' of the p-polarized light that reflects the back surface reflected light 21. signal of.

FIG. 14 shows the result of the differential processing between the output signal c ₂ of the position sensor 17 and the output signal c ₂ ' of the position sensor 16 by the calculation unit 18. Since the signal b ₂ and the signal b ₂ ' are different, the differential processed signal (c ₂ -c ₂ ') becomes the polarized light differential signal (a ₂ -a ₂ ') of the front surface reflected light and the polarized light of the back surface reflected light. A mixed signal of differential signals (b ₂ -b ₂ '). Therefore, it is impossible to accurately obtain the surface position of the substrate 5.

Based on the reflectance that has been recorded in advance as described above, the polarization adjusting unit 12 adjusts the polarization state of each of the reflected lights such that the polarized light signals b ₂ and b ₂ ' of the back surface reflected light 21 are equal, and the front surface is made The polarized light signals a ₂ and a ₂ ' of the reflected light 20 become similar. Fig. 15 shows the light intensity distribution of the s-polarized light outputted by the position sensor 17 after the polarization state is adjusted. FIG. 16 shows the light intensity distribution of the p-polarized light output by the position sensor 16 after the polarization state is adjusted. As shown in FIG. 15, the adjustment is performed by setting each signal shown in FIG. 12 to α times, and as shown in FIG. 16, by setting each signal shown in FIG. 13 to β. Double to perform the adjustment. Each signal is represented after adjustment as follows: g = αa ₂ , h = αb ₂ , i = αc ₂ , g' = βa ₂ ', h' = βb ₂ ', I' = βc ₂ '.

FIG. 17 shows the result of the differential processing between the output signal i of the position sensor 17 and the output signal i' of the position sensor 16 by the calculation unit 18 after the adjustment of the polarized light. Based on the adjustment of the polarized light, the polarized light signal of the back surface reflected light 21 is expressed as follows: h = h', that is, αb ₂ = βb ₂ '; and it is additionally expressed as follows: i-i' = αc _{2 -} βc ₂ '=αa ₂ -βa ₂ '≠0. Therefore, the signal i-i' retained after the differential processing represents the difference a ₂ between the signal a ₂ showing the p-polarized light of the front surface reflected light 20 and the signal a ₂ ' showing the s-polarized light of the front surface reflected light 20 -a ₂ '.

Since the signal a ₂ and the signal a ₂ ' are based on the similar relationship of the reflectance differences between each other, the position of the center of gravity of each signal and its differential signal do not change. Therefore, obtaining the position of the center of gravity of the differential signal (a ₂ - a ₂ ') corresponds to obtaining the surface position of the substrate 5. As described above, the detecting method of the present embodiment also achieves effects similar to those in the first embodiment.

(Third embodiment)

Next, a description will be given of a detecting method according to a third embodiment of the present invention. In the first embodiment, the rear surface reflects light 21 The conditions of the p-polarized light and the s-polarized light are set to be equal. In the present embodiment, the surface position of the substrate 5 can be accurately detected by setting conditions in which the p-polarized light of the rear surface reflected light 21 is equal to the s-polarized light of the front surface reflected light 20, and thereafter The s-polarized light of the surface reflected light 21 is equal to the p-polarized light of the front surface reflected light 20.

Fig. 18 shows the relationship between the incident angle of the detection light 19 for the substrate 5 and the reflectance of the p-polarized light and the s-polarized light. The p-polarized light of the front surface reflected light 20 is displayed by a circle of a black outline, the s-polarized light is displayed by a black solid circle, the p-polarized light of the rear surface reflected light 21 is displayed by a black triangle, and the rear surface reflects the light 21 The s-polarized light is shown by a black solid triangle. As can be seen from Fig. 18, in the vicinity of the incident angle of 80 degrees, the reflectance of the p-polarized light of the rear surface reflected light 21 is equal to the reflectance of the s-polarized light of the front surface reflected light 20, and the back surface reflects the light 21 The reflectance of the s-polarized light is equal to the reflectance of the p-polarized light of the front-surface reflected light 20.

Fig. 19 shows the light intensity distribution of the s-polarized light outputted by the position sensor 17 when the incident angle is set to 70 degrees and the thickness of the substrate 5 is made thin (as shown in Fig. 6). The signal c ₃ outputted from the position sensor 17 is a signal obtained by combining the signal a ₃ of the s-polarized light that reflects the front surface reflected light 20 with the signal b ₃ of the s-polarized light that reflects the back surface reflected light 21 . 20 shows the light intensity distribution of the p-polarized light outputted by the position sensor 16 when the incident angle is set to 70 degrees and the thickness of the substrate 5 is made thin (as shown in FIG. 6). The signal c ₃ ' output by the position sensor 16 is obtained by combining the signal a ₃ ' of the p-polarized light that reflects the front surface reflected light 20 with the signal b ₃ ' of the p-polarized light that reflects the back surface reflected light 21. signal of. Note that in the signals detected by each position sensor, the waveforms in these patterns are normalized to the peaks of the signals with large inputs. That is, b ₃ = b ₃ ' is established. The signal c _{3 of} FIG. 19 and the signal c ₃ ' of FIG. 20 are not signals having a symmetrical relationship with each other.

21 shows the light intensity distribution of the s-polarized light outputted by the position sensor 17 when the incident angle is set to 86 degrees and the thickness of the substrate 5 is made thin (as shown in FIG. 6). The signal c ₄ outputted from the position sensor 17 is a signal obtained by combining the signal a ₄ of the s-polarized light that reflects the front surface reflected light 20 with the signal b ₄ of the s-polarized light that reflects the back surface reflected light 21 . Fig. 22 shows the light intensity distribution of the p-polarized light outputted by the position sensor 16 when the incident angle is set to 86 degrees and the thickness of the substrate 5 is made thin (as shown in Fig. 6). The signal c ₄ ' outputted by the position sensor 16 is obtained by combining the signal a ₄ ' of the p-polarized light that reflects the front surface reflected light 20 with the signal b ₄ ' of the p-polarized light that reflects the back surface reflected light 21. signal of. Note that in the signals detected by each position sensor, the waveforms in these patterns are normalized to the peaks of the signals having large outputs. That is, a ₄ = a ₄ ' is established. The signal c ₄ of Fig. 21 and the signal c ₄ ' of Fig. 22 are not signals having a symmetrical relationship with each other.

Fig. 23 shows the light intensity distribution of the s-polarized light outputted by the position sensor 17 when the incident angle is set to 80 degrees and the thickness of the substrate 5 is made thin (as shown in Fig. 6). The signal c ₅ outputted from the position sensor 17 is a signal obtained by combining the signal a ₅ of the s-polarized light that reflects the front surface reflected light 20 with the signal b ₅ of the s-polarized light that reflects the back surface reflected light 21 . Fig. 24 shows the light intensity distribution of the p-polarized light outputted by the position sensor 16 when the incident angle is set to 80 degrees and the thickness of the substrate 5 is made thin (as shown in Fig. 6). The signal c ₅ ' output by the position sensor 16 is obtained by combining the signal a ₅ ' of the p-polarized light showing the front surface reflected light 20 and the signal b ₅ ' of the p-polarized light showing the back surface reflected light 21 signal of. Note that in the signals detected by each position sensor, the waveforms in these patterns are normalized to the peak of the signal at the large output. That is, a ₅ = b ₅ ' is established. In this figure, a ₅ = b ₅ ', b ₅ = a ₅ ' holds, so that the signals c ₅ and c ₅ ' are signals having a symmetrical relationship with each other.

As described above, the following feature is exhibited: it is possible to make the setting of the signal shapes detected by the position sensors 16 and 17 having a symmetrical relationship with each other depending on the incident angle θ. Note that these signal shapes may also vary depending on the reflectance in the interface between the substrate 5 and the substrate holding unit 6. In addition, the reflectance may also vary depending on the state of the polarized light. Therefore, it is necessary to set the incident angle θ in advance after knowing the reflectance of each polarized light at the interface between the substrate 5 and the substrate holding unit 6. In the above description, it is assumed that the reflectance in the interface is set to 100% for each polarized light. When the incident angle θ is set by collectively changing the reflectance of each polarized light at the interface, or by changing the reflectance of each polarized light, the shape of the signal detected by the position sensors 16 and 17 has The incident angle θ of the symmetrical relationship between each other falls within the range of θ = 60 to 80 degrees.

FIG. 25 shows signals before the differential processing of the signals (a ₅ , b ₅ , a ₅ ', and b ₅ ') detected by the position sensors 16 and 17 by the calculation unit 18. The s-polarized light is shown by the solid line, and the p-polarized light is shown by the broken line. Further, P1 and P2 are output peaks corresponding to each of the polarized lights that have been obtained in advance. The calculation of the differential signal is performed by shifting the signal of the p-polarized light with respect to the signal of the s-polarized light in the +t direction or the -t direction, and by subtracting the signal of the p-polarized light from the signal of the s-polarized light. .

Fig. 26 shows the result of differential processing of a signal for performing p-polarized light based on s-polarized light while shifting the signal of p-polarized light in the +t direction. When the amplitude P of the signal after the differential processing is equal to P1, the maximum position t1 becomes the position As of the front surface reflected light 20 incident on the position sensor 17, and if the offset at this time is represented by Δt, then t1+ Δt becomes the position Bs at which the rear surface reflected light 21 is incident on the position sensor 17. Here, when the amplitude P of the signal after the differential processing is equal to P1, the s-polarized light of the rear surface reflected light 21 and the p-polarized light of the front surface reflected light 20 cancel each other.

FIG. 27 shows a result of differential processing of a signal for performing p-polarized light based on a signal of s-polarized light while shifting a signal of p-polarized light in the -t direction. When the amplitude P of the signal after the differential processing is equal to P2, the maximum position t2 becomes the position Bp at which the rear surface reflected light 21 is incident into the position sensor 16, and if the offset at this time is represented by -Δt, then t2 -Δt becomes the position Ap of the front surface reflected light 20 incident on the position sensor 16. Here, when the amplitude P of the signal after the differential processing is equal to P2, the s-polarized light of the rear surface reflected light 21 and the s-polarized light of the front surface reflected light 20 Light cancels each other.

As described above, according to the detecting method of the present embodiment, the differential processing is performed by shifting the signal detected by one position sensor in at least one direction with respect to the signal detected by the other position sensor, And the surface position of the substrate 5 can thus be detected based on the maximum position and offset of the differential signal. However, when the amplitude of the differential signal is P=P1, the maximum position t1 is in a position opposite to the offset direction (+t), and when the amplitude of the differential signal is P=P2, the maximum position t2 is at The position in the opposite direction to the offset direction (-t). In addition, the differential processing may be a differential processing that subtracts the s-polarized optical signal (solid line) from the p-polarized optical signal (dashed line).

Note that even if an error of a component (material), assembly, adjustment, or the like occurs and does not exhibit the reflectance characteristic as shown in FIG. 18, the differential processing of the present embodiment can be adjusted by polarizing light as in the second embodiment. State to execute.

(Article manufacturing method)

The article manufacturing method according to an embodiment of the present invention is ideal when manufacturing an article such as a micro device (for example, a semiconductor device or the like), a member having a microstructure, or the like. The article manufacturing method may include a step of forming a latent image pattern on the object using the aforementioned exposure apparatus (for example, an exposure process); and a step of developing an object on which the latent image pattern has been formed in the previous step. In addition, the article manufacturing method may include other known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resistance). Etching, cutting, bonding, encapsulation, etc.). The device manufacturing method of the present embodiment is advantageous in at least one of performance, quality, productivity, and production cost of the device as compared with the conventional device manufacturing method.

While the invention has been described with reference to the preferred embodiments thereof, it is understood that the invention is not limited to the illustrative embodiments disclosed. The scope of the following claims should be accorded the broadest interpretation to cover all such modifications and equivalent structures and functions.

The present application claims the benefit of Japanese Patent Application No. 2015-253117, filed on Dec. 25, 2015, which is hereby incorporated by reference.

1‧‧‧ original

2‧‧‧Exposure device body

3‧‧‧Lighting optical system

4‧‧‧Projection optical system

5‧‧‧Substrate

6‧‧‧Substrate holding unit

7‧‧‧ substrate table

8‧‧ ‧ mirror

9‧‧‧Laser Interferometer

10‧‧‧Light source

11‧‧‧Measurement slit

12‧‧‧Polarization unit

13‧‧‧Light projection lens

14‧‧‧Light receiving lens

15‧‧‧Polarized beam splitter

16‧‧‧ position sensor

17‧‧‧ position sensor

18‧‧‧Computation unit

19‧‧‧Detecting light

20‧‧‧ Receiving light (front surface reflected light)

22‧‧‧Projection system

23‧‧‧Light receiving system

Θ‧‧‧incident angle

Claims (10)

A detecting device having a projection system and a light receiving system that projects detection light from an oblique direction with respect to a normal to a surface to be detected of an object to be detected, the light receiving system receiving a reflection reflected by the object to be detected Light, and the detecting device detects a position of the surface to be inspected based on data obtained by the light receiving system, the reflected light including reflected light reflected on the front surface on the surface to be inspected, and transmitted through the surface to be inspected And reflecting light on the rear surface reflected on the rear surface of the object to be detected, the light receiving system comprising a polarization separating unit and a detecting unit, the polarization separating unit separating the reflected light into a first polarized light component and a second polarization a light component, the detecting unit detects the first polarized light component and the second polarized light component, and the projection system or the light receiving system is configured to cause the first polarization of the back surface reflected light obtained by the detecting unit The light component and the second polarized light component of the back surface reflected light are equal, and the projection system or the light receiving system includes a calculation Element, the computing unit based on the obtained by the detecting unit to display the data of the first polarized light component and the difference data between the display data of the second polarized light component of the calculated position. The detecting device of claim 1, wherein the projection system projects the detecting light onto the surface to be inspected such that a reflectance of the first polarized light component of the detecting light in the rear surface and the detecting light The second polarized light component has the same reflectivity in the back surface. The detecting device of claim 1, wherein the projection system or the light receiving system comprises a polarization adjusting unit, the polarization adjusting unit adjusts a polarization state of the reflected light such that the rear surface reflects the light The first polarized light component is equal to the second polarized light component of the back surface reflected light. The detecting device of claim 1, wherein the projection system or the light receiving system is configured to cause a waveform representing a light intensity of the first polarized light component of the front surface reflected light detected by the detecting unit The shape of the data is in a similar relationship to the shape of the waveform data representing the light intensity of the second polarized light component of the surface reflected light detected by the detecting unit. A detecting device having a projection system and a light receiving system that projects detection light from an oblique direction with respect to a normal to a surface to be detected of an object to be detected, the light receiving system receiving a reflection reflected by the object to be detected Light, and the detecting device detects a position of the surface to be inspected based on data obtained by the light receiving system, the reflected light including reflected light reflected on the front surface on the surface to be inspected, and transmitted through the surface to be inspected And reflecting light on the rear surface reflected on the rear surface of the object to be detected, the light receiving system comprising a polarization separating unit and a detecting unit, the polarization separating unit separating the reflected light into a first polarized light component and a second polarization a light component, the detecting unit detects the first polarized light component and the second polarized light component, and the projection system or the light receiving system is configured such that the representation is determined by the inspection a shape of the waveform data of the light intensity of the first polarized light component of the back surface reflected light detected by the measuring unit and a light intensity indicating the second polarized light component of the front surface reflected light detected by the detecting unit The shape of the waveform data is a similar relationship, and the shape of the waveform data indicating the light intensity of the first polarized light component of the front surface reflected light detected by the detecting unit and the rear surface detected by the detecting unit are represented The shape of the waveform data of the light intensity of the second polarized light component of the reflected light is a similar relationship, and the projection system or the light receiving system includes a computing unit that displays the first polarization based on the display obtained by the detecting unit The difference data between the light component and the data of the second polarized light component is used to calculate the position in the normal direction. The detecting device of claim 5, wherein the calculating unit obtains the differential data to cancel the first polarized light component of the back surface reflected light and the second polarized light component of the front surface reflected light, or thereby The first polarized light component of the front surface reflected light and the second polarized light component of the rear surface reflected light are cancelled. The detecting device of claim 5, wherein the projection system projects the detecting light onto the surface to be inspected such that a reflectance of the first polarized light component of the detecting light in the rear surface and the detecting light The reflectance of the second polarized light component in the surface to be detected is equal, and the reflectance of the second polarized light component of the detected light in the back surface is different from the first polarized light component of the detected light The reflectance in the surface to be inspected is equal. For example, the detection device of claim 5, The projection system or the light receiving system includes a polarization adjusting unit that adjusts a polarization state of the reflected light such that a light intensity of each polarized light component detected by the detecting unit is a similar relationship . An exposure apparatus that transfers a pattern of a master onto an exposure area on a substrate, the exposure apparatus comprising a detecting device as in the first aspect of the patent application, the detecting device detecting a position of a surface of the substrate as a surface to be inspected. A method of producing an article comprising: exposing an exposure process of a substrate by using an exposure apparatus as disclosed in claim 9; and developing a development process of the substrate which has been exposed.