CN117192917A - Vertical measurement device, vertical measurement method and photolithography machine - Google Patents

Abstract

The invention provides a vertical measurement device, a vertical measurement method and a photolithography machine. The vertical measurement device includes: an illumination module, a projection light path module and a detection light path module. The illumination module is used to provide a light beam, and the projection light path The 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 the surface to be measured, and is received by the detection light path module after being reflected by the surface to be measured. The detection light path module The vertical measurement error caused by the angular deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured are calculated and obtained. The 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.

Description

Vertical measurement device, vertical measurement method and photolithography machine

Technical field

The present invention relates to the technical field of photolithography, and in particular to a vertical measurement device, a vertical measurement method and a photolithography machine.

Background technique

A projection lithography machine is a device that projects the pattern on the mask onto the surface of a substrate (such as a silicon wafer) through a projection objective. During the exposure process of the lithography machine, if the silicon wafer is defocused or tilted relative to the focal plane of the projection objective, causing certain areas in the exposure field to be outside the effective focal depth, it will seriously affect the lithography quality, so it must be used The focusing and leveling system precisely controls the position of the silicon wafer within the exposure field of view.

Focusing and leveling systems generally use 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 use 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, mechanism vibration, control errors, etc. may cause angular deviations, which may in turn cause errors in vertical measurement results.

Contents of the invention

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.

In order to solve the above technical problems, the present invention provides a vertical measurement device, which includes: an illumination module, a projection light path module and a detection light path module;

The lighting module is used to provide a light beam;

The projection light path module includes a scanning reflection unit;

Wherein, the light beam emitted by the lighting module is reflected by the scanning reflection unit and then illuminated to the surface to be measured. After being reflected by the surface to be measured, it is received by the detection light path module. The detection light path module calculates and obtains the scanning reflection. The vertical measurement error caused by the unit angle deviation and the absolute measurement height of the surface to be measured.

Optionally, the projection light path module includes a light splitting unit. The light beam enters the light splitting unit after being reflected by the scanning reflection unit, and is divided into a first light beam and a second light beam with different bandwidths through the light splitting unit. The first beam is reflected once by the scanning reflection unit and reflected by the surface to be measured and then received by the detection optical path module. The second beam is reflected twice by the scanning reflection unit and reflected by the surface to be measured. After being received by the detection optical path module, the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first beam and the second beam and the absolute measurement height of the surface to be measured are calculated based on the differential measurement.

Optionally, the vertical measurement error caused by the angular deviation of the scanning reflection unit of the second light beam is twice the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first light beam.

Optionally, the detection light path module includes a first detector and a second detector. The first detector is used to receive the first beam and obtain the first height. The second detector is used to receive the first beam. Two beams and gain second height.

Optionally, the first height includes the height error caused by the angular deviation of the scanning reflection unit of the first light beam and the absolute measured height of the surface to be measured, and the second height includes the height error caused by the angular deviation of the scanning reflection unit of the second light beam. The height error and the absolute measured height of the surface to be measured, the first height and the second height are calculated based on differential measurements. The vertical deviation caused by the angular deviation of the scanning reflection unit of the first beam and the second beam is calculated. Measure the error and calculate the absolute measured height of the surface to be measured.

Optionally, when the scanning reflection unit is in the 90° phase and the 270° phase, the second height is calculated based on the light intensity of the second beam received by the second detector.

Optionally, the first light beam or the second light beam is reflected by the surface to be measured and is received by the detection light path module through the imaging light path module. The imaging light path module includes a first detection slit and a second detection slit. slit, the first detection slit is used to detect the first light beam in combination with the detection light path module, the second detection slit is used in combination with the detection light path module to detect the second light beam, and the third detection slit is used in combination 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.

Optionally, the projection light path module includes a projection slit, and the width of the first detection slit is equal to the width of the projection slit.

Optionally, when the scanning reflection unit is in the 90° phase, the energy of the second detector is the first energy value; when the scanning reflection unit is in the 270° phase, the energy of the second detector is the third energy value. Two energy values, 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, the scanning reflection unit is located at 0 ° phase light spot is at the position of the second detection slit.

Based on the same inventive concept, the present invention also provides a vertical measurement method, including:

The lighting module emits a beam of light;

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 light 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 angular deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured.

Optionally, the beam enters the spectroscopic unit after being reflected by the scanning reflection unit, and is divided into a first beam and a second beam with different bandwidths by the spectrometry unit. The first beam is reflected once by the scanning reflection unit. And after being reflected by the surface to be measured, it is received by the detection light path module, the second beam is reflected twice by the scanning reflection unit and is received by the detection light path module after being reflected by the surface to be measured; and the result is calculated according to the differential measurement. The vertical measurement error caused by the angular deviation of the scanning reflection unit of the first beam and the second beam is calculated, and the absolute measurement height of the surface to be measured is calculated.

Optionally, calculating the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first beam and the second 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 beam and obtains a first height, where the first height includes the height error caused by the angular deviation of the scanning reflection unit of the first beam and the absolute measured height of the surface to be measured;

The second detector receives the second beam and obtains a second height; the second height includes the height error caused by the angular deviation of the scanning reflection unit of the second beam and the absolute measurement height of the surface to be measured;

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

Optionally, the vertical measurement error caused by the angular deviation of the scanning reflection unit of the second light beam is twice the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first light beam.

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

Based on the same inventive concept, the present invention also provides a photolithography machine, including the vertical measurement device described in any one of the above.

In the vertical measurement device, vertical measurement method and lithography machine provided by the present invention, the lighting module emits a light beam. The light beam is reflected by the scanning reflection unit and then irradiated to the surface to be measured. After being reflected by the surface to be measured, the light beam is reflected by the surface to be measured. The detection light path module receives, and the detection light path module calculates and obtains the vertical measurement error caused by the angular deviation of the scanning reflection unit, and the absolute measurement height of the surface to be measured. The 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.

Further, the beam enters the spectroscopic unit after being reflected by the scanning reflection unit, and is divided into a first beam and a second beam with different bandwidths by the spectrometry unit. The first beam is reflected once by the scanning reflection unit and is reflected by the surface to be measured before being detected. The optical path module receives, and the second beam is reflected twice by the scanning reflection unit and is received by the detection optical path module after being reflected by the surface to be measured, and the vertical deviation caused by the angular deviation of the scanning reflection unit of the first beam and the second beam is calculated based on the differential measurement. Measure the error and calculate the absolute measured height of the surface to be measured. This differential calculation process can eliminate part of the errors of the measurement system itself, solve the vertical height measurement error caused by the angle error of the scanning reflection unit, and achieve absolute height measurement.

Further, at least two displacement sensors are provided on the side of the scanning reflection unit away from the beam for monitoring 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 surface to be measured. The absolute measurement height is conducive to improving the stability of the system's focusing and leveling measurement performance.

Description of the drawings

Those of ordinary skill in the art will understand that the drawings are provided for a better understanding of the invention and do not constitute any limitation on the scope of the invention. in:

Figure 1 is a schematic structural diagram of a vertical measurement device in Embodiment 1 of the present invention.

Figure 2 is a schematic diagram of the angle and vertical measurement errors of the scanning reflection unit in Embodiment 1 of the present invention.

3 is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit is at 0° phase in Embodiment 1 of the present invention.

4 is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit is in a 90° phase in Embodiment 1 of the present invention.

FIG. 5 is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit is in the 270° phase in Embodiment 1 of the present invention.

6 is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit is at 0° phase in Embodiment 1 of the present invention.

7 is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit is in a 90° phase in Embodiment 1 of the present invention.

FIG. 8 is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit is in the 270° phase in Embodiment 1 of the present invention.

Figure 9 is a schematic structural diagram of a vertical measurement device in Embodiment 2 of the present invention.

FIG. 10 is a schematic diagram of the angle monitoring of the scanning reflection unit in FIG. 9 .

Figure 11 is a schematic diagram of the displacement sensor testing principle in Figure 9.

Figure 12 is a flow chart of the vertical measurement method according to the embodiment of the present invention.

In the attached picture:

10-Lighting module; 101-Light source; 102-Lighting lens group;

20-Projection light path module; 201-Projection slit; 202-Projection front group; 203-Scanning reflection unit; 204-Spectral unit; 204a-First dichroic mirror; 204b-Second dichroic mirror; 205-No. A reflecting mirror; 206-projection rear group; 207-second reflecting mirror; 208-first displacement sensor; 208a-first laser; 208b-first focusing lens; 208c-first converging lens; 208d-first four quadrants Detector; 209-second displacement sensor; 209a-second laser; 209b-second focusing lens; 209c-second converging lens; 209d-second four-quadrant detector;

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

40-detection light path module; 401-detection light path component; 401a-first detection light path component; 401b-second detection light path component; 402-detector; 402a-first detector; 402b-second detector;

50-surface to be tested;

61-The first light spot; 62-The second light spot.

Detailed ways

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

As used in this invention, the singular forms "a", "an" and "the" include plural referents, the term "or" is generally used in its sense including "and/or", and the term "several" The term "at least two" is usually used in a meaning including "at least one", and the term "at least two" is usually used in a meaning including "two or more". In addition, the terms "first" and "th "Second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying the relative importance or implicitly indicating the quantity of the technical features indicated. Thus, features defined as “first”, “second”, and “third” may explicitly or implicitly include one or at least two of these features. In addition, as used in the present invention, one element is disposed on another element, which usually only means that there is a connection, coupling, matching or transmission relationship between the two elements, and the relationship between the two elements may be direct or indirect through an intermediate element. connection, coupling, cooperation or transmission, and cannot be understood as indicating or implying the spatial positional relationship between two elements, that is, one element can be in any position inside, outside, above, below or to one side of another element, unless the content Also clearly stated. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Figure 1 is a schematic structural diagram of a vertical measurement device in Embodiment 1 of the present invention. As shown in Figure 1, this embodiment provides a vertical measurement device, including: an illumination module 10, a projection light path module 20, and a detection light path module 40. The projection light path module 20 includes a spectroscopic unit 204 and a scanning reflection unit 203. The 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 through 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. After being received by the detection optical path module 40, the second beam is reflected twice by the scanning reflection unit 203 and reflected by the surface to be measured 50 before being received by the detection optical path module 40. The first beam is calculated according to the differential measurement. The vertical measurement error caused by the angular deviation of the scanning reflection unit between the light beam and the second light beam is calculated, and the absolute measurement height of the surface to be measured 50 is calculated.

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

The projection light path module 20 includes a projection slit 201, a pre-projection group 202, a scanning reflection unit 203, a light splitting unit 204, a first reflection mirror 205, a post-projection group 206 and a second reflection mirror 207 in sequence. The light splitting unit 204 includes a first dichroic mirror 204a and a second dichroic mirror 204b. The first dichroic mirror 204a is completely transparent to the light beam of the first spectral component and completely reflective to the light beam of the second spectral component. The bandwidth of the light beam of the first spectral component and the light beam of the second spectral component are different, for example The beam wavelength of the first spectral component is 450nm~600nm, and the beam wavelength of the second spectral component is 600nm~750nm. The light beam passes through the projection slit to generate a light spot, and the projection front group 202 adjusts the light spot into uniform illumination light. The light spot adopts a rectangular light spot. The uniform illumination light irradiates the scanning reflection unit 203 . The scanning reflection unit 203 is, for example, a scanning mirror. The scanning reflection unit 203 includes two mutually parallel planes, and the light spot is irradiated on one of the planes to form a reflected beam. The light beam is reflected by the scanning reflection unit 203 and then illuminates the first dichroic mirror 204a. The first dichroic mirror 204a converts the light beam into a first light beam and a second light beam. The first light beam and the second light beam are The bandwidths are different. The first beam is part of the beam transmitted by the first dichroic mirror 204a, and the second beam is part of the beam reflected by the first dichroic mirror 204a. The wavelength of the first beam is, for example, 450 nm. ~600nm, the wavelength of the second beam is, for example, 600nm ~ 750nm. The first beam is reflected by the first reflector 205 and then enters the second dichroic mirror 204b. The second dichroic mirror 204b also transmits the first beam. The first beam is concentrated by the projection group 206 to uniformly illuminate the light. After the convergence, The first light beam is reflected by the second reflector 207 and then irradiates onto the surface 50 to be measured. The second beam irradiates the scanning reflection unit 203 again, which means that the second beam has experienced two reflections from the scanning reflection unit 203. Therefore, the angle deviation of the two scanning reflection units is also introduced into the second beam. After the second reflection by the scanning reflection unit 203, the second beam enters the second dichroic mirror 204b. The second dichroic mirror 204b also reflects the second beam. After the second beam is projected, the group 207 converges the uniform illumination light. , the concentrated second light beam is reflected by the second reflecting mirror 207 and then irradiates onto the surface 50 to be measured.

The vertical measurement device also includes an imaging optical path module 30, which sequentially includes a third reflecting mirror 301, a front imaging group 302, a third dichroic mirror 303, a fourth reflecting mirror 304, a rear imaging group 305 and a detection Slit306. The post-imaging group 305 includes a first post-imaging group 305a and a second post-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 the width of the first detection slit 306a. twice the width. The first beam is reflected by the surface to be measured 50 and then illuminates the third reflector 301. After being reflected by the third reflector 301, it enters the imaging front group 302. The imaging front group 302 adjusts the first beam into uniform illumination light and then enters the third The dichroic mirror 303 and the third dichroic mirror 303 also transmit the first light beam. The first light beam enters the first post-imaging group 305a. The first post-imaging group 305a adjusts the parallel first light beam into a converged first light beam. The converged first beam enters the first detection slit 306a. The second beam is reflected by the surface to be measured 50 and then illuminates the third reflector 301. After being reflected by the third reflector 301, it enters the imaging front group 302. The imaging front group 302 adjusts the second beam into uniform illumination light and then enters the third The dichroic mirror 303 and the third dichroic mirror 303 also reflect the second light beam. The second light beam irradiates the fourth reflecting mirror 304 and enters the second imaging rear group 305b after being reflected by the fourth reflecting mirror 304. The second imaging The rear group 305b adjusts the parallel second light beam into a converged second light beam, and the converged second light beam enters the second detection slit 306b.

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

In this embodiment, according to the imaging relationship, it can be concluded 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. 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, mechanism vibration, control errors, etc.

Figure 2 is a schematic diagram of the angle and vertical measurement errors of the scanning reflection unit in Embodiment 1 of the present invention. As shown in Figure 2, 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 height measurement error of the surface to be measured 50 (silicon wafer surface) is different from the height measurement error of the scanning reflection unit. The relationship between angular deviation is:

Among them, Δh is the beam offset, α is the angular deviation of the scanning reflection unit, f is the focal length of the post-projection optical path of the projection light path module, θ is the normal angle between the beam and the surface to be measured, Δd is the angle deviation caused by the scanning reflection unit Vertical measurement error.

The first height includes the height error caused by the angular deviation of the scanning reflection unit of the first beam and the absolute measured height of the surface to be measured, and the second height includes the height error caused by the angular deviation of the scanning reflection unit of the second beam and The absolute measured height of the surface to be measured, the first height and the second height are calculated based on differential measurements, and the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first beam and the second beam is calculated, and Calculate the absolute measured height of the surface to be measured.

H1＝Δd ₁ +d (2)

H2＝Δd ₂ +d (3)

Among them, H1 is the first height, H2 is the second height, Δd ₁ is the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first beam, Δd ₂ is the vertical measurement caused by the angular deviation of the scanning reflection unit of the second beam Error, d is the absolute measurement height of the surface to be measured.

It can be known from formula (1):

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

Δh ₁ =2*f*tan2α (6)

Δh ₂ =2*f*tan4α (7)

It can be known from the properties of the sine function that the vertical measurement error caused by the angular deviation of the scanning reflection unit of the second beam is twice the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first beam, that is, the formula is:

Δd ₂ =2Δd ₁ (8)

Among them, Δh ₁ is the offset of the first beam, Δh ₂ is the offset of the second beam, Δh is the offset of the beam, α is the angular deviation of the scanning reflection unit, f is the focal length of the post-projection optical path of the projection optical path module, θ is the normal angle between the beam and the surface to be measured, Δd is the vertical measurement error caused by the angular deviation of the scanning reflection unit, Δd ₁ is the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first beam, Δd ₂ is the second beam The vertical measurement error caused by the angular deviation of the scanning reflection unit.

According to formula (2), formula (3) and formula (8), the vertical measurement error Δd ₁ caused by the angular deviation of the scanning reflection unit of the first beam and the angular deviation of the scanning reflection unit of the second beam can be calculated using differential measurement calculations. The vertical measurement error Δd ₂ and the absolute measurement height d of the surface to be measured. The differential calculation process can also eliminate some errors of the measurement system itself, realize the monitoring of the angle of the scanning reflection unit 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. .

3 is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit is at 0° phase in Embodiment 1 of the present invention. 4 is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit is in a 90° phase in Embodiment 1 of the present invention. FIG. 5 is a schematic diagram of the positional relationship between the first light spot and the first detection slit when the scanning reflection unit is in the 270° phase in Embodiment 1 of the present invention. 6 is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit is at 0° phase in Embodiment 1 of the present invention. 7 is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit is in a 90° phase in Embodiment 1 of the present invention. FIG. 8 is a schematic diagram of the positional relationship between the second light spot and the second detection slit when the scanning reflection unit is in the 270° phase in Embodiment 1 of the present invention.

In this embodiment, the first light beam is reflected once by the scanning reflection unit 203 to form the first light spot 61 on the first detector 402a. The second light beam is reflected twice by the scanning reflection unit 203 and forms 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 . As shown in Figures 3 to 5, the projection slit 201 through which the first light beam passes is of the same size as 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 first light spot 61 is equal to the width of the projection slit 201. The first detection slits 306a have equal widths, as shown in FIG. 3 . The scanning amplitude of the scanning reflection unit 203 is exactly the same as the width of the first detection slit 306a. Therefore, when the scanning reflection unit is in the 90° phase and the 270° phase, the signals at the positions of the two first light spots 61 are acquired to calculate the value of the surface to be measured 50 Measure the first height value vertically, as shown in Figures 4 and 5. In the same way, the second height is calculated based on the signals of the two second light spots 62 of the second beam on the second detector 402b when the scanning reflection unit 203 is in the 90° phase and the 270° phase. . 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 to meet the requirements of the second light spot 62 when detecting two phase positions. Energy is used to calculate the vertically measured second height value of the surface to be measured 50 . As shown in Figures 7 and 8, when the phase of the scanning reflection unit 203 is 90°, the energy of the second detector 402b is the first energy value A. When the phase of the scanning reflection unit 203 is 270°, the energy of the second detector 402b is the first energy value A. For the second energy value B, the offset of the center position of the second light spot 62 can be calculated through (A-B)/(A+B) and the width of the second light spot 62, that is, when the phase of the scanning reflection unit 203 is 0°, the second light spot can be calculated 62, as shown in Figure 6. In other words, the scanning reflection single 203 is calculated according to the difference between the first energy value and the second energy value, the ratio of the sum of the first energy value and the second energy value, and the width of the second light spot 62 When the element is at 0° phase, the second light spot 62 is at the position of the second detection slit 306b.

Figure 9 is a schematic structural diagram of a vertical measurement device according to Embodiment 2 of the present invention. As shown in FIG. 9 , this embodiment provides a vertical measurement device, including: an illumination module 10 , a projection light path module 20 , an imaging light path module 30 and a detection light path module 40 . The lighting module 10 includes a light source 101 and an lighting lens group 102 in sequence. The projection light path module 20 includes a projection slit 201, a pre-projection group 202, a scanning reflection unit 203, a first reflection mirror 205, a post-projection group 206 and a second reflection mirror 207 in sequence. At least two displacement sensors are provided on a 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 sequentially includes a third reflector 301, a front imaging group 302, a fourth reflector 304, a fifth reflector 307, a rear imaging group 305, and a detection slit 306. The detection light path module 40 includes a detection light 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 described again. The difference between the second embodiment and the first embodiment is that a dichroic mirror is not used, but a displacement sensor is used to monitor the angular deviation of the scanning reflection unit 203 .

FIG. 10 is a schematic diagram of the angle monitoring of the scanning reflection unit in FIG. 9 . As shown in Figure 10, 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 certain fixed value. When scanning the reflection unit 203 When the angle 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). According to the scanning center position, the first displacement sensor 208 and the second displacement sensor 209 The difference in readings of the two displacement sensors 209 can be used to calculate the angular deviation of the scanning reflection unit 203, and then converted into the actual measurement result error, that is, the height value error caused by the angular deviation α of the scanning reflection unit 203 is calculated, and substituted into the value to be calculated by the detector 402. Measure the vertical height measurement value of the surface 50 to obtain the absolute height of the surface 50 to be measured.

Figure 11 is a schematic diagram of the displacement sensor testing principle in Figure 9. As shown in Figure 11, the displacement sensor is a four-quadrant detector. The four-quadrant detector includes a first laser 208a, a second laser 209a, a first focusing lens 208b, a second focusing lens 209b, a first condensing lens 208c, and a first focusing lens 208c. The two converging lenses 209c, the first four-quadrant detector 208d and the second four-quadrant detector 209d calculate the angular deviation of the scanning reflection unit 203 by calculating changes in spot energy within the four quadrants. The measurement method of the scanning reflection unit based on the four-quadrant detector is as follows: the first laser 208a and the second laser 209a emit light spots that are focused on the surface of the scanning reflection unit 203 through the first focusing lens 208b and the second focusing lens 209b, and the reflected light beam The light spot is again received by the first four-quadrant detector 208d and the second four-quadrant detector 209d by the first condensing lens 208c and the second condensing lens 209c. When the scanning reflection unit 203 is in the zero position, the light spot is located at the first four-quadrant detector 208d. and the center of the second four-quadrant detector 209d. At this time, the energy of the four areas A, B, C and D is equal. When the light spot deviates from the zero position, the signals of the first four-quadrant detector 208d and the second four-quadrant detector 209d The intensity V(A+B)/V(C+D) has a fixed relationship with the position of the reflective surface of the scanning reflection unit 203, and the corresponding relationship can be obtained through calculation, calibration and high-order polynomial fitting. Calculating the positions of the two sets of sensor detection points can accurately calculate the deflection angle of the scanning reflection unit 203, and substitute it into the aforementioned formula (6) to calculate the vertical measurement error of the surface to be measured 50, and calculate the measured surface according to formula (2). Measure the absolute height of surface 50.

Figure 12 is a flow chart of the vertical measurement method according to the embodiment of the present invention. As shown in Figure 12, this embodiment also provides a vertical measurement method, including:

Step S10, the lighting module emits a beam;

Step S20, 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 light path module after being reflected by the surface to be measured;

Step S30: The detection light path module calculates and obtains the vertical measurement error caused by the angular deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured.

In one embodiment, the beam enters the spectroscopic unit after being reflected by the scanning reflection unit, and is divided into a first beam and a second beam with different bandwidths through the spectrometry unit. The first beam passes through the scanning reflection unit. The second beam is reflected once and is received by the detection light path module after being reflected by the surface to be measured. The second beam is reflected twice by the scanning reflection unit and is received by the detection light path module after being reflected by the surface to be measured; and according to differential measurement Calculate the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first beam and the second beam, and calculate the absolute measurement height of the surface to be measured.

Calculating the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first beam and the second 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 beam and obtains a first height, where the first height includes the height error caused by the angular deviation of the scanning reflection unit of the first beam and the absolute measured height of the surface to be measured;

The second detector receives the second beam and obtains a second height; the second height includes the height error caused by the angular deviation of the scanning reflection unit of the second beam and the absolute measurement height of the surface to be measured;

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

Wherein, the vertical measurement error caused by the angular deviation of the scanning reflection unit of the second light beam is twice the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first light beam.

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

This embodiment also provides a photolithography machine, including the vertical measurement device described in any one of the above.

In summary, it can be seen that in the vertical measurement device, vertical measurement method and lithography machine provided by the embodiments of the present invention, the lighting module emits a light beam, and the light beam is reflected by the scanning reflection unit and then irradiated to the surface to be measured. The surface to be measured is reflected and received by the detection light path module; the detection light path module calculates and obtains the vertical measurement error caused by the angular deviation of the scanning reflection unit and the absolute measurement height of the surface to be measured. The 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.

Further, the beam enters the spectroscopic unit after being reflected by the scanning reflection unit, and is divided into a first beam and a second beam with different bandwidths by the spectrometry unit. The first beam is reflected once by the scanning reflection unit and is reflected by the surface to be measured before being detected. The optical path module receives, and the second beam is reflected twice by the scanning reflection unit and is received by the detection optical path module after being reflected by the surface to be measured. The scanning of the first beam and the second beam is calculated based on the differential measurement. The vertical measurement error caused by the angular deviation of the reflection unit is reflected, and the absolute measurement height of the surface to be measured is calculated. The differential calculation process can also eliminate part of the errors of the measurement system itself, solve the vertical height measurement error caused by the angle error of the scanning reflection unit, and achieve absolute height measurement.

Further, at least two displacement sensors are provided on a side of the scanning reflection unit away from the beam for monitoring 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. Improve the stability of system focusing and leveling measurement performance.

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

In addition, it should be recognized that although the present invention has been disclosed above in preferred embodiments, the above embodiments are not intended to limit the present invention. For any person familiar with the art, without departing from the scope of the technical solution of the present invention, they can use the technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into equivalent changes. Example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims (15)

1. A vertical measurement device, comprising: the device comprises an illumination module, a projection light path module and a detection light path module;

the illumination module is used for providing a light beam;

the projection light path module comprises a scanning reflection unit;

the light beam emitted by the illumination module irradiates the surface to be measured after being reflected by the scanning reflection unit, 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 a vertical measurement error caused by the angle deviation of the scanning reflection unit and an absolute measurement height of the surface to be measured.

2. The vertical measurement device according to claim 1, wherein the projection light path module comprises a beam splitting unit, the light beam enters the beam splitting unit after being reflected by the scanning reflection unit, the light beam is split into a first light beam and a second light beam with different bandwidths by the beam splitting unit, the first light beam is received by the detection light path module after being reflected once by the scanning reflection unit and reflected by the surface to be measured, the second light beam is received by the detection light path module after being reflected twice by the scanning reflection unit and reflected by the surface to be measured, and a vertical measurement error caused by an angle deviation of the scanning reflection unit of the first light beam and the second light beam and an absolute measurement height of the surface to be measured are calculated according to differential measurement.

3. The vertical measurement device of claim 2, wherein the vertical measurement error caused by the angular deviation of the scanning reflection unit of the second light beam is twice the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first light beam.

4. A vertical measurement device according to claim 3, wherein the detection light path module comprises a first detector for receiving the first light beam and obtaining a first height and a second detector for receiving the second light beam and obtaining a second height.

5. The vertical measurement device according to claim 4, wherein the first height includes a height error caused by an angular deviation of a scanning reflection unit of a first light beam and an absolute measurement height of the surface to be measured, the second height includes a height error caused by an angular deviation of a scanning reflection unit of a second light beam and an absolute measurement height of the surface to be measured, the first height and the second height calculate vertical measurement errors caused by the angular deviations of the scanning reflection units of the first light beam and the second light beam from differential measurement, and calculate the absolute measurement height of the surface to be measured.

6. The vertical measurement device of claim 4, wherein the second height is calculated from the intensity of the second light beam received by the second detector when the scanning reflection unit is located at a 90 ° phase and a 270 ° phase.

7. The vertical measurement device of claim 4, wherein the first light beam or the second light beam is received by the detection light path module through an imaging light path module after being reflected by the surface to be measured, the imaging light path module comprising a first detection slit and a second detection slit, the first detection slit being used in combination with the detection light path module to detect the first light beam, the second detection slit being used in combination with the detection light path module to detect the second light beam, the second detection slit having a width twice the width of the first detection slit.

8. The vertical measurement device of claim 7, wherein the projection light path module comprises a projection slit, and wherein the width of the first detection slit is equal to the width of the projection slit.

9. The vertical measurement device of claim 7, wherein the energy of the second detector is a first energy value when the scanning reflection unit is located at a 90 ° phase; when the scanning reflection unit is positioned at the 270-degree phase, the energy of the second detector is a second energy value; and calculating the position of the light spot in the second detection slit when the scanning reflection unit is positioned at the 0-degree phase according to 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.

10. A vertical measurement method, comprising:

the lighting module emits a light beam;

the light beam irradiates the surface to be detected after being reflected by the scanning reflection unit, and is received by the detection light path module after being reflected by the surface to be detected;

and the detection light path module calculates and obtains a vertical measurement error caused by the angle deviation of the scanning reflection unit and an absolute measurement height of the surface to be measured.

11. The vertical measurement method according to claim 10, wherein the light beam enters a beam splitting unit after being reflected by the scanning reflection unit, the light beam is split into a first light beam and a second light beam with different bandwidths by the beam splitting unit, the first light beam is received by the detection light path module after being reflected once by the scanning reflection unit and reflected by the surface to be measured, and the second light beam is received by the detection light path module after being reflected twice by the scanning reflection unit and reflected by the surface to be measured; and calculating a vertical measurement error caused by the angle deviation of the scanning reflection units 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.

12. The vertical measurement method according to claim 11, wherein calculating a vertical measurement error caused by an angular deviation of a scanning reflection unit of the first light beam and the second light beam from a differential measurement, and calculating an absolute measurement height of the surface to be measured comprises:

the first detector receives the first light beam and obtains a first height, wherein the first height comprises a height error caused by the 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 comprises a height error caused by the 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 relation 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, calculating the vertical measurement error caused by the angle deviation of the scanning reflection units of the first light beam and the second light beam by adopting differential measurement, and calculating the absolute measurement height of the surface to be measured.

13. The vertical measurement method according to claim 12, wherein the vertical measurement error caused by the angular deviation of the scanning reflection unit of the second light beam is twice as large as the vertical measurement error caused by the angular deviation of the scanning reflection unit of the first light beam.

14. The vertical measurement method according to claim 10, wherein the angular deviation of the scanning reflection unit is calculated using at least two displacement sensors.

15. A lithographic apparatus comprising a vertical measuring device according to any one of claims 1 to 9.