Vertical measurement device, vertical measurement method and photolithography machine

Abstract

The present invention provides a vertical measurement device, a vertical measurement method and a photolithography machine. The vertical measurement device includes: an illumination module, a projection optical path module and a detection optical path module. The illumination module is used to provide a light beam, and the projection optical path module includes a scanning reflection unit; wherein the light beam emitted by the illumination module is reflected by the scanning reflection unit and then irradiated to a surface to be measured, and then reflected by the surface to be measured and received by the detection optical path module, and the detection optical path module calculates and obtains the vertical measurement error caused by the angle deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured. The present invention can calculate the vertical height measurement error caused by the angle deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured, thereby realizing the monitoring of the angle of the scanning reflection unit and the improvement of the measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the field of photolithography technology, and in particular to a vertical measurement device, a vertical measurement method and a photolithography machine. Background Art

[0002] A projection lithography machine is a device that projects the pattern on a mask onto the surface of a substrate (such as a silicon wafer) through a projection lens. During the exposure process of the lithography machine, if the silicon wafer is defocused or tilted relative to the focal plane of the projection lens, causing some areas in the exposure field to be outside the effective focal depth, the quality of the lithography will be seriously affected. Therefore, a focusing and leveling system must be used to accurately control the position of the silicon wafer in the exposure field.

[0003] The focusing and leveling system generally uses the triangulation principle to measure the vertical position or surface shape of the substrate surface. The focusing and leveling system includes a scanning reflection unit. Using the scanning reflection unit to modulate the light flux and using the triangulation principle to measure the vertical position is a high-precision vertical measurement solution. However, since the scanning reflection unit itself is a movable mechanism, long-term use or mechanism vibration, control error and other reasons will cause it to have an angle deviation, which will cause errors in the vertical measurement results. Summary of the invention

[0004] The object of the present invention is to provide a vertical measurement device, a vertical measurement method and a photolithography machine to solve the problem of vertical height measurement error caused by the angle error of the scanning reflection unit.

[0005] In order to solve the above technical problems, the present invention provides a vertical measurement device, comprising: an illumination module, a projection optical path module and a detection optical path module;

[0006] The lighting module is used to provide a light beam;

[0007] The projection optical path module includes a scanning reflection unit;

[0008] Among them, the light beam emitted by the lighting module is reflected by the scanning and reflecting unit and then irradiated to the surface to be measured, and is received by the detection optical path module after being reflected by the surface to be measured. The detection optical path module calculates and obtains the vertical measurement error caused by the angle deviation of the scanning and reflecting unit and the absolute measurement height of the surface to be measured.

[0009] Optionally, the projection optical path module includes a spectroscopic unit, and the light beam enters the spectroscopic unit after being reflected by the scanning and reflecting unit, and is divided into a first light beam and a second light beam with different bandwidths by the spectroscopic unit. The first light beam is reflected once by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module. The second light beam is reflected twice by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module. The vertical measurement error caused by the angle deviation of the scanning and reflecting units of the first and second light beams and the absolute measurement height of the surface to be measured are calculated based on differential measurement.

[0010] Optionally, the vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the second light beam is twice the vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the first light beam.

[0011] Optionally, the detection optical path module includes a first detector and a second detector, the first detector is used to receive the first light beam and obtain a first height, and the second detector is used to receive the second light beam and obtain a second height.

[0012] Optionally, the first height includes the height error caused by the angle deviation of the scanning reflection unit of the first light beam and the absolute measurement height of the surface to be measured, and the second height includes the height error caused by the angle deviation of the scanning reflection unit of the second light beam and the absolute measurement height of the surface to be measured. The first height and the second height are calculated based on differential measurement to calculate the vertical measurement error caused by the angle deviation of the scanning reflection units of the first light beam and the second light beam, and the absolute measurement height of the surface to be measured is calculated.

[0013] Optionally, when the scanning reflection unit is at a phase of 90° and a phase of 270°, the second height is calculated according to the light intensity of the second light beam received by the second detector.

[0014] Optionally, after the first light beam or the second light beam is reflected by the surface to be measured, it is received by the detection light path module through the imaging light path module, and the imaging light path module includes a first detection slit and a second detection slit, the first detection slit is combined with the detection light path module to detect the first light beam, and the second detection slit is combined with the detection light path module to detect the second light beam, and the width of the second detection slit is twice the width of the first detection slit.

[0015] Optionally, the projection optical path module includes a projection slit, and the width of the first detection slit is equal to the width of the projection slit.

[0016] Optionally, when the scanning reflection unit is at a phase of 90°, the energy of the second detector is a first energy value, and when the scanning reflection unit is at a phase of 270°, the energy of the second detector is a second energy value. The position of the light spot at the second detection slit when the scanning reflection unit is at a phase of 0° is calculated based on the ratio of the difference between the first energy value and the second energy value to the sum of the first energy value and the second energy value and the width of the light spot.

[0017] Based on the same inventive concept, the present invention also provides a vertical measurement method, comprising:

[0018] The lighting module emits a light beam;

[0019] The light beam is reflected by the scanning reflection unit and irradiated to the surface to be measured, and is received by the detection optical path module after being reflected by the surface to be measured;

[0020] The detection optical path module calculates and obtains the vertical measurement error caused by the angle deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured.

[0021] Optionally, the light beam enters a spectroscopic unit after being reflected by the scanning and reflecting unit, and is divided into a first light beam and a second light beam with different bandwidths by the spectroscopic unit, the first light beam is reflected once by the scanning and reflecting unit and then reflected by the surface to be measured and then received by the detection optical path module, the second light beam is reflected twice by the scanning and reflecting unit and then reflected by the surface to be measured and then received by the detection optical path module; and the vertical measurement error caused by the angle deviation of the scanning and reflecting units of the first and second light beams is calculated based on differential measurement, and the absolute measurement height of the surface to be measured is calculated.

[0022] Optionally, calculating the vertical measurement error caused by the angle deviation of the scanning reflection unit of the first light beam and the second light beam according to the differential measurement, and calculating the absolute measurement height of the surface to be measured includes:

[0023] The first detector receives the first light beam and obtains a first height, wherein the first height includes a height error caused by an angle deviation of a scanning reflection unit of the first light beam and an absolute measurement height of the surface to be measured;

[0024] The second detector receives the second light beam and obtains a second height; the second height includes a height error caused by an angle deviation of a scanning reflection unit of the second light beam and an absolute measurement height of the surface to be measured;

[0025] According to the relationship between the height error caused by the angle deviation of the scanning reflection unit of the first light beam and the height error caused by the angle deviation of the scanning reflection unit of the second light beam, differential measurement is used to calculate the vertical measurement error caused by the angle deviation of the scanning reflection unit of the first light beam and the second light beam, and the absolute measurement height of the surface to be measured is calculated.

[0026] Optionally, the vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the second light beam is twice the vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the first light beam.

[0027] Optionally, at least two displacement sensors are used to calculate the angular deviation of the scanning reflection unit.

[0028] Based on the same inventive concept, the present invention also provides a lithography machine, comprising any of the vertical measurement devices described above.

[0029] In the vertical measurement device, vertical measurement method and lithography machine provided by the present invention, the illumination module emits a light beam, the light beam is reflected by the scanning reflection unit and irradiates the surface to be measured, and is received by the detection light path module after being reflected by the surface to be measured, and the detection light path module calculates and obtains the vertical measurement error caused by the angle deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured. The present invention can calculate the vertical height measurement error caused by the angle deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured, thereby realizing the monitoring of the angle of the scanning reflection unit and improving the measurement accuracy.

[0030] Furthermore, after the light beam is reflected by the scanning and reflecting unit, it enters the spectroscopic unit and is divided into a first light beam and a second light beam with different bandwidths by the spectroscopic unit. The first light beam is reflected once by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module. The second light beam is reflected twice by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module. The vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the first and second light beams is calculated based on the differential measurement, and the absolute measurement height of the surface to be measured is calculated. This differential calculation process can eliminate the error of part of the measurement system itself, solve the vertical height measurement error caused by the angle error of the scanning and reflecting unit, and realize the measurement of absolute height.

[0031] Furthermore, at least two displacement sensors are arranged on the side of the scanning reflection unit away from the light beam, which are used to monitor the angular deviation of the scanning reflection unit to calculate the vertical height measurement error caused by the angular deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured, which is beneficial to improving the stability of the system's focusing and leveling measurement performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Those skilled in the art will appreciate that the accompanying drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0033] Figure 1 It is a schematic diagram of the structure of the vertical measurement device in the first embodiment of the present invention.

[0034] Figure 2 Schematic diagram of the scanning reflection unit angle and vertical measurement error in the first embodiment of the present invention.

[0035] Figure 3 It is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit in the first embodiment of the present invention is at a phase of 0°.

[0036] Figure 4 It is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit in the first embodiment of the present invention is located at a phase of 90°.

[0037] Figure 5 It is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit in the first embodiment of the present invention is located at a phase of 270°.

[0038] Figure 6 It is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit in the first embodiment of the present invention is at a phase of 0°.

[0039] Figure 7 It is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit in the first embodiment of the present invention is located at a phase of 90°.

[0040] Figure 8 It is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit in the first embodiment of the present invention is located at a phase of 270°.

[0041] Fig. 9 It is a schematic diagram of the structure of the vertical measurement device in the second embodiment of the present invention.

[0042] Fig.10 yes Fig. 9 Schematic diagram of the scanning reflection unit angle monitoring.

[0043] Fig.11 yes Fig. 9 Schematic diagram of the displacement sensor test principle.

[0044] Fig.12 It is a flow chart of the vertical measurement method according to an embodiment of the present invention.

[0045] In the attached figure:

[0046] 10- lighting module; 101- light source; 102- lighting mirror assembly;

[0047] 20-projection optical path module; 201-projection slit; 202-pre-projection group; 203-scanning reflection unit; 204-splitting unit; 204a-first dichroic mirror; 204b-second dichroic mirror; 205-first reflector; 206-post-projection group; 207-second reflector; 208-first displacement sensor; 208a-first laser; 208b-first focusing lens; 208c-first converging lens; 208d-first four-quadrant detector; 209-second displacement sensor; 209a-second laser; 209b-second focusing lens; 209c-second converging lens; 209d-second four-quadrant detector;

[0048] 30-imaging optical path module; 301-third reflector; 302-imaging front group; 303-third dichroic mirror; 304-fourth reflector; 305-imaging rear group; 305a-first imaging rear group; 305b-second imaging rear group; 306-detection slit; 306a-first detection slit; 306b-second detection slit; 307-fifth reflector;

[0049] 40-detection optical path module; 401-detection optical path component; 401a-first detection optical path component; 401b-second detection optical path component; 402-detector; 402a-first detector; 402b-second detector;

[0050] 50-surface to be tested;

[0051] 61-first light spot; 62-second light spot. DETAILED DESCRIPTION

[0052] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.

[0053] As used in the present invention, the singular forms "one", "an" and "the" include plural objects, the term "or" is usually used to include the meaning of "and / or", the term "several" is usually used to include the meaning of "at least one", and the term "at least two" is usually used to include the meaning of "two or more". In addition, the terms "first", "second" and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second" and "third" can explicitly or implicitly include one or at least two of the features. In addition, as used in the present invention, an element is arranged on another element, which usually only indicates that there is a connection, coupling, matching or transmission relationship between the two elements, and the connection, coupling, matching or transmission between the two elements can be direct or indirect through an intermediate element, and cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, an element can be in any orientation such as inside, outside, above, below or on one side of another element, unless the content clearly indicates otherwise. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0054] Figure 1 Schematic diagram of the structure of the vertical measurement device in the first embodiment of the present invention. Figure 1 As shown, this embodiment provides a vertical measurement device, including: an illumination module 10, a projection optical path module 20 and a detection optical path module 40, the projection optical path module 20 includes a spectroscopic unit 204 and a scanning reflection unit 203, the illumination module 10 is used to provide a light beam, the light beam is divided into a first light beam and a second light beam with different bandwidths by the spectroscopic unit 204, the first light beam is reflected once by the scanning reflection unit 203 and is reflected by the surface to be measured 50 and then received by the detection optical path module 40, the second light beam is reflected twice by the scanning reflection unit 203 and is reflected by the surface to be measured 50 and then received by the detection optical path module 40, the vertical measurement error caused by the angle deviation of the scanning reflection unit of the first light beam and the second light beam is calculated according to the differential measurement, and the absolute measurement height of the surface to be measured 50 is calculated.

[0055] Specifically, the lighting module 10 includes a light source 101 and a lighting lens group 102 in sequence. The light source 101 is used to provide a light beam, and the lighting lens group 102 adjusts the light beam emitted by the light source 101 into a uniform lighting light.

[0056] The projection optical path module 20 includes a projection slit 201, a projection front group 202, a scanning reflection unit 203, a beam splitter unit 204, a first reflector 205, a projection rear group 206, and a second reflector 207 in sequence. The beam splitter unit 204 includes a first dichroic mirror 204a and a second dichroic mirror 204b. The first dichroic mirror 204a fully transmits the light beam of the first spectral component and fully reflects the light beam of the second spectral component. The bandwidths of the light beams of the first spectral component and the second spectral component are different. For example, the wavelength of the light beam of the first spectral component is 450nm to 600nm, and the wavelength of the light beam of the second spectral component is 600nm to 750nm. The light beam generates a light spot through the projection slit, and the projection front group 202 adjusts the light spot to a uniform illumination light. The light spot is a rectangular light spot. The uniform illumination light is irradiated onto the scanning reflection unit 203. The scanning reflection unit 203 is, for example, a scanning reflection mirror. The scanning reflection unit 203 includes two parallel planes, and the light spot is irradiated on one of the planes to form a reflected light beam. After being reflected by the scanning reflection unit 203, the light beam is irradiated on the first dichroic mirror 204a. The first dichroic mirror 204a divides the light beam into a first light beam and a second light beam. The bandwidth of the first light beam and the second light beam are different. The first light beam is the part of the light beam transmitted by the first dichroic mirror 204a, and the second light beam is the part of the light beam reflected by the first dichroic mirror 204a. The wavelength of the first light beam is, for example, 450nm to 600nm, and the wavelength of the second light beam is, for example, 600nm to 750nm. After being reflected by the first reflection mirror 205, the first light beam enters the second dichroic mirror 204b, and the second dichroic mirror 204b also transmits the first light beam. After the first light beam is projected, the uniform illumination light is converged by the group 206. The converged first light beam is reflected by the second reflection mirror 207 and irradiated on the surface to be measured 50. The second light beam is irradiated onto the scanning reflection unit 203 again, that is, the second light beam is reflected twice by the scanning reflection unit 203, and therefore, the second light beam is also introduced into the second light beam by two scanning reflection unit angle deviations. After the second reflection by the scanning reflection unit 203, the second light beam enters the second dichroic mirror 204b, and the second dichroic mirror 204b also reflects the second light beam. After the second light beam is projected, the uniform illumination light is converged by the group 207, and the converged second light beam is reflected by the second reflection mirror 207 and irradiated onto the surface 50 to be measured.

[0057] The vertical measurement device also includes an imaging optical path module 30, which includes a third reflector 301, a front imaging group 302, a third dichroic mirror 303, a fourth reflector 304, a rear imaging group 305 and a detection slit 306 in sequence. The rear imaging group 305 includes a first rear imaging group 305a and a second rear imaging group 305b, and the detection slit 306 includes a first detection slit 306a and a second detection slit 306b. The first detection slit 306a is used to detect the first light beam, the second detection slit 306b is used to detect the second light beam, and the width of the second detection slit 306b is twice the width of the first detection slit 306a. The first light beam is reflected by the surface to be measured 50 and irradiates the third reflector 301. After being reflected by the third reflector 301, it enters the front imaging group 302. The front imaging group 302 adjusts the first light beam into uniform illumination light and then enters the third dichroic mirror 303. The third dichroic mirror 303 also transmits the first light beam. The first light beam enters the first rear imaging group 305a. The first rear imaging group 305a adjusts the parallel first light beam into a converged first light beam. The converged first light beam enters the first detection slit 306a. The second light beam is reflected by the surface to be measured 50 and irradiates the third reflector 301. After being reflected by the third reflector 301, it enters the front imaging group 302. The front imaging group 302 adjusts the second light beam into uniform illumination light and enters the third dichroic mirror 303. The third dichroic mirror 303 also reflects the second light beam. The second light beam is irradiated onto the fourth reflector 304. After being reflected by the fourth reflector 304, it enters the second rear imaging group 305b. The second rear imaging group 305b adjusts the parallel second light beam into a converged second light beam. The converged second light beam enters the second detection slit 306b.

[0058] The detection optical path module 40 includes a detection optical path component 401 and a detector 402. The detection optical path component 401 includes a first detection optical path component 401a and a second detection optical path component 401b. The detector 402 includes a first detector 402a and a second detector 402b. The first detection optical path component 401a is used to converge the first light beam, and the second detection optical path component 401b is used to converge the second light beam; the first detector 402a is used to receive the first light beam and obtain a first height, and the second detector 402b is used to receive the second light beam and obtain a second height. The first light beam passes through the first detection slit 306a and enters the first detection optical path component 401a. After converging the first light beam, the first detection optical path component 401a enters the first detector 402a. The first detector 402a detects the first height of the surface 50 to be measured according to the first light beam. The second light beam passes through the second detection slit 306b and enters the second detection optical path component 401b. The second detection optical path component 401b converges the second light beam and enters the second detector 402b. The second detector 402b detects the second height of the surface 50 to be measured according to the second light beam.

[0059] In this embodiment, it can be concluded from the imaging relationship that the spot position on the first detector 402a or the second detector 402b depends on the height of the surface to be measured 50 and the angle of the scanning reflection unit 203. The height of the surface to be measured 50 is the information to be measured, and the angle of the scanning reflection unit 203 is determined by the scanning amplitude and the initial zero angle, wherein the scanning amplitude is used for light flux scanning measurement, and the zero angle is the initial position of the scanning reflection unit 203. The scanning reflection unit 203 itself is a movable mechanism, and its angle deviation is caused by long-term use or mechanism vibration, control error, etc.

[0060] Figure 2 FIG. 1 is a schematic diagram of the scanning reflection unit angle and vertical measurement error in the first embodiment of the present invention. Figure 2 As shown, when the initial angle of the scanning reflection unit 203 deviates, the angle deviation of the scanning reflection unit 203 will cause a vertical measurement error, that is, the relationship between the height measurement error of the surface to be measured 50 (silicon wafer surface) and the angle deviation of the scanning reflection unit is:

[0061]

[0062] Among them, Δh is the beam offset, α is the angle deviation of the scanning reflection unit, f is the focal length of the projection optical path module after projection, θ is the normal angle between the beam and the surface to be measured, and Δd is the vertical measurement error caused by the angle deviation of the scanning reflection unit.

[0063] The first height includes the height error caused by the angle deviation of the scanning and reflecting unit of the first light beam and the absolute measurement height of the surface to be measured, and the second height includes the height error caused by the angle deviation of the scanning and reflecting unit of the second light beam and the absolute measurement height of the surface to be measured. The first height and the second height are calculated based on differential measurement to calculate the vertical measurement error caused by the angle deviation of the scanning and reflecting units of the first light beam and the second light beam, and the absolute measurement height of the surface to be measured is calculated.

[0064] H1=Δd1+d (2)

[0065] H2=Δd2+d (3)

[0066] Wherein, H1 is the first height, H2 is the second height, Δd1 is the vertical measurement error caused by the angle deviation of the scanning reflection unit of the first light beam, Δd2 is the vertical measurement error caused by the angle deviation of the scanning reflection unit of the second light beam, and d is the absolute measurement height of the surface to be measured.

[0067] From formula (1), we can know that:

[0068]

[0069]

[0070] According to optical knowledge, if the angle deviation of the scanning reflection unit is α, the modulation angle of the first light beam after one reflection by the scanning reflection unit is 2 times α, and the modulation angle of the second light beam after two reflections by the scanning reflection unit is 4 times α. The calculation formula for the relationship between the light beam (first light beam or second light beam) offset and the angle deviation of the scanning reflection unit is:

[0071] Δh1=2*f*tan2α (6)

[0072] Δh2=2*f*tan4α (7)

[0073] From the properties of the sine function, it can be seen that the vertical measurement error caused by the angle deviation of the scanning reflection unit of the second light beam is twice the vertical measurement error caused by the angle deviation of the scanning reflection unit of the first light beam, that is, the formula is:

[0074] Δd2=2Δd1 (8)

[0075] Among them, Δh1 is the first light beam offset, Δh2 is the second light beam offset, Δh is the light beam offset, α is the angle deviation of the scanning reflection unit, f is the focal length of the projection light path module after projection, θ is the angle between the light beam and the normal of the surface to be measured, Δd is the vertical measurement error caused by the angle deviation of the scanning reflection unit, Δd1 is the vertical measurement error caused by the angle deviation of the scanning reflection unit of the first light beam, and Δd2 is the vertical measurement error caused by the angle deviation of the scanning reflection unit of the second light beam.

[0076] According to formula (2), formula (3) and formula (8), the vertical measurement error Δd1 caused by the angle deviation of the scanning reflection unit of the first light beam, the vertical measurement error Δd2 caused by the angle deviation of the scanning reflection unit of the second light beam and the absolute measurement height d of the surface to be measured can be calculated by differential measurement. The differential calculation process can also eliminate some errors of the measurement system itself, realize the monitoring of the scanning reflection unit angle and improve the measurement accuracy, solve the vertical height measurement error caused by the angle error of the scanning reflection unit, and realize the measurement of absolute height.

[0077] Figure 3 It is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit in the first embodiment of the present invention is at a phase of 0°. Figure 4 It is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit in the first embodiment of the present invention is located at a phase of 90°. Figure 5 It is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit in the first embodiment of the present invention is located at a phase of 270°. Figure 6It is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit in the first embodiment of the present invention is at a phase of 0°. Figure 7 It is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit in the first embodiment of the present invention is located at a phase of 90°. Figure 8 It is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit in the first embodiment of the present invention is located at a phase of 270°.

[0078] In this embodiment, the first light beam is reflected once by the scanning reflection unit 203 to form a first light spot 61 on the first detector 402a. The second light beam is reflected twice by the scanning reflection unit 203 to form a second light spot 62 on the second detector 402b. The first light beam and the second light beam have different scanning angles, so the scanning positions of the first light spot 61 and the second light spot 62 are different during the scanning process of the scanning reflection unit 203. Figures 3 to 5 As shown, the projection slit 201 through which the first light beam passes is equal to the first detection slit 306a, that is, the width of the first detection slit 306a is equal to the width of the projection slit 201, and the width of the first light spot 61 is equal to the first detection slit 306a. Figure 3 The scanning amplitude of the scanning reflection unit 203 is just consistent with the width of the first detection slit 306a, so the signals of the positions of the two first light spots 61 are obtained when the scanning reflection unit is at a phase of 90° and a phase of 270° to calculate the vertical measurement first height value of the surface to be measured 50, as shown in FIG. Figure 4 and Figure 5 Similarly, the second height is calculated based on the signals of the two second light spots 62 of the second light beam on the second detector 402b when the scanning reflection unit 203 is at a phase of 90° and 270°. The scanning position of the second light spot 62 is twice the scanning position of the first light spot 61, and the width of the second detection slit 306b is twice the width of the first detection slit 306a, so as to meet the energy of the second light spot 62 when detecting two phase positions, and is used to calculate the second height value of the vertical measurement of the surface 50 to be measured. Figure 7 and Figure 8 As shown, when the phase of the scanning reflection unit 203 is 90°, the energy of the second detector 402b is the first energy value A, and when the phase of the scanning reflection unit 203 is 270°, the energy of the second detector 402b is the second energy value B. The offset of the center position of the second light spot 62 can be calculated by (AB) / (A+B) and the width of the second light spot 62, that is, the position of the second light spot 62 when the phase of the scanning reflection unit 203 is 0°, as shown in FIG. Figure 6In other words, the position of the second light spot 62 at the second detection slit 306b when the scanning reflection unit 203 is at a phase of 0° is calculated according to the ratio of the difference between the first energy value and the second energy value and the sum of the first energy value and the second energy value and the width of the second light spot 62.

[0079] Fig. 9 Schematic diagram of the vertical measurement device structure of the second embodiment of the present invention. Fig. 9 As shown, this embodiment provides a vertical measurement device, including: an illumination module 10, a projection optical path module 20, an imaging optical path module 30 and a detection optical path module 40. The illumination module 10 includes a light source 101 and an illumination mirror group 102 in sequence. The projection optical path module 20 includes a projection slit 201, a projection front group 202, a scanning reflection unit 203, a first reflector 205, a projection rear group 206 and a second reflector 207 in sequence. At least two displacement sensors are provided on the side of the scanning reflection unit 203 away from the light beam, for monitoring the angular deviation of the scanning reflection unit 203. The displacement sensor can be a laser displacement sensor, a capacitive sensor, or a grating displacement sensor. The imaging optical path module 30 includes a third reflector 301, an imaging front group 302, a fourth reflector 304, a fifth reflector 307, an imaging rear group 305, and a detection slit 306 in sequence. The detection optical path module 40 includes a detection optical path component 401 and a detector 402. The optical device in the second embodiment has the same function as that in the first embodiment, and will not be repeated here. The difference between the second embodiment and the first embodiment is that a displacement sensor is used instead of a dichroic mirror to monitor the angle deviation of the scanning reflection unit 203 .

[0080] Fig.10 yes Fig. 9 Schematic diagram of the scanning reflection unit angle monitoring in FIG. Fig.10 As shown, the distance between the first displacement sensor 208 and the second displacement sensor 209 is set to L, and the initial distance between the first displacement sensor 208 and the second displacement sensor 209 is set to be equal or a fixed value. When the angle of the scanning reflection unit 203 changes, there is a difference δd between the readings of the first displacement sensor 208 and the second displacement sensor 209, then the angle change α can be calculated as atan(δd / L), and the angle deviation of the scanning reflection unit 203 can be calculated according to the difference between the readings of the first displacement sensor 208 and the second displacement sensor 209 when scanning the center position, and then converted into the actual measurement result error, that is, the height value error caused by the angle deviation α of the scanning reflection unit 203 is calculated, and substituted into the vertical height measurement value of the surface to be measured 50 calculated by the detector 402 to obtain the absolute height of the surface to be measured 50.

[0081] Fig.11 yes Fig. 9Schematic diagram of displacement sensor testing principle. Fig.11 As shown, the displacement sensor is a four-quadrant detector, which includes a first laser 208a, a second laser 209a, a first focusing lens 208b, a second focusing lens 209b, a first converging lens 208c, a second converging lens 209c, a first four-quadrant detector 208d and a second four-quadrant detector 209d. The angular deviation of the scanning reflection unit 203 is calculated by calculating the change in the spot energy in the four quadrants. The scanning reflection unit measurement method based on the four-quadrant detector is as follows: the first laser 208a and the second laser 209a emit light spots which are converged on the surface of the scanning reflection unit 203 by the first focusing lens 208b and the second focusing lens 209b; the reflected light beams are received by the first converging lens 208c and the second converging lens 209c again by the first four-quadrant detector 208d and the second four-quadrant detector 209d; when the scanning reflection unit 203 is at zero position, the light spots are located at the center of the first four-quadrant detector 208d and the second four-quadrant detector 209d; at this time, the energies of the four regions A, B, C and D are equal; when the light spots deviate from the zero position, the signal intensities V(A+B) / V(C+D) of the first four-quadrant detector 208d and the second four-quadrant detector 209d have a fixed relationship with the position of the reflection surface of the scanning reflection unit 203, and their corresponding relationship can be obtained by calculation, calibration and high-order polynomial fitting. By calculating the positions of the two sets of sensor detection points, the deflection angle of the scanning reflection unit 203 can be accurately calculated, and substituted into the aforementioned formula (6) to calculate the vertical measurement error of the surface 50 to be measured, and the absolute height of the surface 50 to be measured can be calculated according to formula (2).

[0082] Fig.12 : is a flow chart of the vertical measurement method according to an embodiment of the present invention. Fig.12 As shown, this embodiment also provides a vertical measurement method, including:

[0083] Step S10, the lighting module emits a light beam;

[0084] Step S20, the light beam is reflected by the scanning reflection unit and irradiated to the surface to be measured, and is received by the detection optical path module after being reflected by the surface to be measured;

[0085] Step S30: the detection optical path module calculates and obtains the vertical measurement error caused by the angle deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured.

[0086] In one embodiment, the light beam enters a spectroscopic unit after being reflected by the scanning and reflecting unit, and is divided into a first light beam and a second light beam with different bandwidths by the spectroscopic unit, the first light beam is reflected once by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module, the second light beam is reflected twice by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module; and the vertical measurement error caused by the angle deviation of the scanning and reflecting units of the first and second light beams is calculated based on differential measurement, and the absolute measurement height of the surface to be measured is calculated.

[0087] Calculating the vertical measurement error caused by the angle deviation of the scanning reflection unit of the first light beam and the second light beam according to the differential measurement, and calculating the absolute measurement height of the surface to be measured includes:

[0088] The first detector receives the first light beam and obtains a first height, wherein the first height includes a height error caused by an angle deviation of a scanning reflection unit of the first light beam and an absolute measurement height of the surface to be measured;

[0089] The second detector receives the second light beam and obtains a second height; the second height includes a height error caused by an angle deviation of a scanning reflection unit of the second light beam and an absolute measurement height of the surface to be measured;

[0090] According to the relationship between the height error caused by the angle deviation of the scanning reflection unit of the first light beam and the height error caused by the angle deviation of the scanning reflection unit of the second light beam, differential measurement is used to calculate the vertical measurement error caused by the angle deviation of the scanning reflection unit of the first light beam and the second light beam, and the absolute measurement height of the surface to be measured is calculated.

[0091] The vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the second light beam is twice the vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the first light beam.

[0092] In another embodiment, at least two displacement sensors are used to calculate the angular deviation of the scanning reflection unit.

[0093] This embodiment also provides a lithography machine, comprising any of the vertical measurement devices described above.

[0094] In summary, in the vertical measurement device, vertical measurement method and lithography machine provided by the embodiments of the present invention, the illumination module emits a light beam, the light beam is reflected by the scanning reflection unit and then irradiated to the surface to be measured, and is received by the detection optical path module after being reflected by the surface to be measured; the detection optical path module calculates and obtains the vertical measurement error caused by the angle deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured. The present invention can calculate the vertical height measurement error caused by the angle deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured, thereby realizing the monitoring of the angle of the scanning reflection unit and improving the measurement accuracy.

[0095] Furthermore, after the light beam is reflected by the scanning and reflecting unit, it enters the spectroscopic unit and is divided into a first light beam and a second light beam with different bandwidths by the spectroscopic unit. The first light beam is reflected once by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module. The second light beam is reflected twice by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module. The vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the first and second light beams is calculated based on the differential measurement, and the absolute measurement height of the surface to be measured is calculated. The differential calculation process can also eliminate some errors of the measurement system itself, solve the vertical height measurement error caused by the angle error of the scanning and reflecting unit, and realize the measurement of absolute height.

[0096] Furthermore, at least two displacement sensors are provided on the side of the scanning reflection unit away from the light beam, for monitoring the angle deviation of the scanning reflection unit, so as to calculate the vertical height measurement error caused by the angle deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured, thereby improving the stability of the focusing and leveling measurement performance of the system.

[0097] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other. In addition, the different parts between the various embodiments can also be used in combination with each other, and the present invention is not limited to this.

[0098] In addition, it should be recognized that although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still belongs to the scope of protection of the technical solution of the present invention.

Claims

1. A vertical measuring device, characterized in that: include: Illumination module, projection light path module and detection light path module; The lighting module is used to provide a light beam; The projection optical path module includes a scanning reflection unit; The light beam emitted by the illumination module is reflected by the scanning and reflecting unit and then irradiated to the surface to be measured, and then reflected by the surface to be measured and then received by the detection optical path module, and the detection optical path module calculates and obtains the vertical measurement error caused by the angle deviation of the scanning and reflecting unit and the absolute measurement height of the surface to be measured; In which, the projection optical path module includes a spectroscopic unit, the light beam enters the spectroscopic unit after being reflected by the scanning and reflecting unit, and is divided into a first light beam and a second light beam with different bandwidths by the spectroscopic unit, the first light beam is reflected once by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module, the second light beam is reflected twice by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module, and the vertical measurement error caused by the angle deviation of the scanning and reflecting units of the first and second light beams and the absolute measurement height of the surface to be measured are calculated based on differential measurement.

2. The vertical measuring device according to claim 1, characterized in that: The vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the second light beam is twice the vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the first light beam.

3. The vertical measuring device according to claim 2, characterized in that: The detection optical path module includes a first detector and a second detector, the first detector is used to receive the first light beam and obtain a first height, and the second detector is used to receive the second light beam and obtain a second height.

4. The vertical measuring device according to claim 3, characterized in that: The first height includes the height error caused by the angle deviation of the scanning and reflecting unit of the first light beam and the absolute measurement height of the surface to be measured, and the second height includes the height error caused by the angle deviation of the scanning and reflecting unit of the second light beam and the absolute measurement height of the surface to be measured. The first height and the second height are calculated based on differential measurement to calculate the vertical measurement error caused by the angle deviation of the scanning and reflecting units of the first light beam and the second light beam, and the absolute measurement height of the surface to be measured is calculated.

5. The vertical measuring device according to claim 3, characterized in that: When the scanning reflection unit is at a phase of 90° and a phase of 270°, the second height is calculated according to the light intensity of the second light beam received by the second detector.

6. The vertical measuring device according to claim 3, characterized in that: After the first light beam or the second light beam is reflected by the surface to be measured, it passes through the imaging light path module and is received by the detection light path module. The imaging light path module includes a first detection slit and a second detection slit. The first detection slit is combined with the detection light path module to detect the first light beam, and the second detection slit is combined with the detection light path module to detect the second light beam. The width of the second detection slit is twice the width of the first detection slit.

7. The vertical measuring device according to claim 6, characterized in that: The projection optical path module comprises a projection slit, and the width of the first detection slit is equal to the width of the projection slit.

8. The vertical measuring device according to claim 6, characterized in that: When the scanning reflection unit is at a phase of 90°, the energy of the second detector is a first energy value; when the scanning reflection unit is at a phase of 270°, the energy of the second detector is a second energy value; the position of the light spot at the second detection slit when the scanning reflection unit is at a phase of 0° is calculated based on the ratio of the difference between the first energy value and the second energy value to the sum of the first energy value and the second energy value and the width of the light spot.

9. A vertical measurement device, characterized in that: include: Illumination module, projection light path module and detection light path module; The lighting module is used to provide a light beam; The projection optical path module comprises a scanning reflection unit, and at least two displacement sensors are arranged on a side of the scanning reflection unit away from the light beam, for monitoring the angle deviation of the scanning reflection unit; The light beam emitted by the illumination module is reflected by the scanning and reflecting unit and then irradiated to the surface to be measured, and then reflected by the surface to be measured and then received by the detection optical path module, and the detection optical path module calculates and obtains the vertical measurement error caused by the angle deviation of the scanning and reflecting unit and the absolute measurement height of the surface to be measured; Among them, when the angle of the scanning reflection unit changes, there is a difference in the readings of at least two of the displacement sensors. The angle deviation of the scanning reflection unit is calculated according to the difference in the readings of at least two of the displacement sensors, and then the height value error caused by the angle deviation of the scanning reflection unit is calculated, and the height value error is substituted into the detection optical path module to calculate the vertical height measurement value of the surface to be measured, and the absolute height of the surface to be measured is obtained.

10. A vertical measurement method, characterized in that: include: The lighting module emits a light beam; The light beam is reflected by the scanning reflection unit and irradiated to the surface to be measured, and is received by the detection optical path module after being reflected by the surface to be measured; The detection optical path module calculates and obtains the vertical measurement error caused by the angle deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured; Wherein, the light beam enters the spectroscopic unit after being reflected by the scanning and reflecting unit, and is divided into a first light beam and a second light beam with different bandwidths by the spectroscopic unit, the first light beam is reflected once by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module, and the second light beam is reflected twice by the scanning and reflecting unit and is reflected by the surface to be measured and then received by the detection optical path module; And the vertical measurement error caused by the angle deviation of the scanning reflection unit of the first light beam and the second light beam is calculated according to the differential measurement, and the absolute measurement height of the surface to be measured is calculated.

11. The vertical measurement method according to claim 10, characterized in that: Calculating the vertical measurement error caused by the angle deviation of the scanning reflection unit of the first light beam and the second light beam according to the differential measurement, and calculating the absolute measurement height of the surface to be measured includes: The first detector receives the first light beam and obtains a first height, wherein the first height includes a height error caused by an angle deviation of a scanning reflection unit of the first light beam and an absolute measurement height of the surface to be measured; The second detector receives the second light beam and obtains a second height, wherein the second height includes a height error caused by an angle deviation of a scanning reflection unit of the second light beam and an absolute measurement height of the surface to be measured; According to the relationship between the height error caused by the angle deviation of the scanning reflection unit of the first light beam and the height error caused by the angle deviation of the scanning reflection unit of the second light beam, differential measurement is used to calculate the vertical measurement error caused by the angle deviation of the scanning reflection unit of the first light beam and the second light beam, and the absolute measurement height of the surface to be measured is calculated.

12. The vertical measurement method according to claim 11, characterized in that: The vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the second light beam is twice the vertical measurement error caused by the angle deviation of the scanning and reflecting unit of the first light beam.

13. A vertical measurement method, characterized in that: include: The lighting module emits a light beam; The light beam is reflected by the scanning reflection unit and irradiated to the surface to be measured, and is received by the detection optical path module after being reflected by the surface to be measured; The detection optical path module calculates and obtains the vertical measurement error caused by the angle deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured; Among them, at least two displacement sensors are used to calculate the angular deviation of the scanning reflection unit. When the angle of the scanning reflection unit changes, there is a difference in the readings of at least two of the displacement sensors. The angular deviation of the scanning reflection unit can be calculated based on the difference in the readings of at least two of the displacement sensors, and then the vertical measurement error caused by the angular deviation of the scanning reflection unit is calculated, and the vertical height measurement value of the surface to be measured calculated by the detection optical path module is substituted into it to obtain the absolute height of the surface to be measured.

14. A photolithography machine, characterized in that: A vertical measuring device comprising any one of claims 1 to 9.

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