Self-tracing two-dimensional displacement measuring device

Abstract

The invention discloses a self-tracing two-dimensional displacement measuring device, which relates to the technical field of precise displacement measurement and comprises a first radiation source, a second radiation source, a wafer fixing plate, a first silicon wafer, a second silicon wafer, a third silicon wafer, a first radiation detector, a second radiation detector and an XY two-dimensional displacement platform, the device comprises a displacement measurement module in the X direction and a displacement measurement module in the Y direction. The first silicon wafer and the second silicon wafer are fixed on the wafer fixing plate in parallel; the third silicon wafer is parallel to the second silicon wafer, and the distance from the third silicon wafer to the second silicon wafer is equal to the distance from the first silicon wafer to the second silicon wafer; the third silicon wafer is fixed on the side wall of the XY two-dimensional displacement platform; and the XY two-dimensional displacement platform drives the third silicon wafer to move together, and in the displacement process, the third silicon wafer and the second silicon wafer are kept parallel, and the distance is not changed. According to the invention, two-dimensional displacement measurement can be realized at the same time, and the measurement resolution can reach the sub-nanometer level.

Description

Technical Field

[0001] The invention relates to the technical field of precision displacement measurement, and in particular to a self-traceable two-dimensional displacement measurement device. Background Art

[0002] With the development of high-end manufacturing, the requirements for nanometer-level high-precision displacement measurement technology are becoming higher and higher. At present, the high-precision two-dimensional displacement measurement devices mainly include two-dimensional grating displacement measurement systems. The two-dimensional grating displacement measurement system has extremely high requirements for grating processing quality, the overall structure is relatively complex, and the measurement results cannot be directly traced back to the definition of meters. Therefore, in some metrological occasions, especially those with extremely high requirements for resolution and accuracy, the two-dimensional grating displacement measurement system is difficult to meet the measurement needs. Summary of the invention

[0003] The purpose of the present invention is to provide a self-traceable two-dimensional displacement measurement device, which can simultaneously realize two-dimensional displacement measurement, the measurement resolution can reach sub-nanometer level, and the measurement results can be directly traced back to the definition of meter.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] In a first aspect, the present invention provides a self-traceable two-dimensional displacement measurement device, comprising: a first ray source, a second ray source, a wafer fixing plate, a first silicon wafer, a second silicon wafer, a third silicon wafer, a first radiation detector, a second radiation detector and an XY two-dimensional displacement platform; the crystal planes of the first silicon wafer are first and second crystal planes that are perpendicular to each other.

[0006] The first ray source, the first silicon wafer, the second silicon wafer, the third silicon wafer and the first radiation detector constitute a displacement measurement module in the X direction.

[0007] The second ray source, the first silicon wafer, the second silicon wafer, the third silicon wafer and the second radiation detector constitute a displacement measurement module in the Y direction.

[0008] The first silicon wafer and the second silicon wafer are fixed in parallel on the wafer fixing plate; the third silicon wafer is parallel to the second silicon wafer, and the distance from the third silicon wafer to the second silicon wafer is equal to the distance from the first silicon wafer to the second silicon wafer.

[0009] The third silicon wafer is fixed to the side wall of the XY two-dimensional displacement platform; the XY two-dimensional displacement platform drives the third silicon wafer to move together, and during the displacement process, the third silicon wafer and the second silicon wafer remain parallel and the distance between them remains unchanged.

[0010] Optionally, the planar size, thickness and crystal orientation of the first silicon wafer and the second silicon wafer are completely consistent.

[0011] Optionally, a size of the third silicon wafer is larger than sizes of the first silicon wafer and the second silicon wafer.

[0012] Optionally, the measurement principle of the displacement measurement module in the X direction specifically includes:

[0013] The rays emitted by the first ray source are incident on the first crystal plane of the first silicon wafer at a Bragg angle and undergo Laue diffraction, and are divided into two beams of first diffracted light. The two beams of first diffracted light are incident on the second silicon wafer and undergo Laue diffraction again, thereby generating second diffracted light. The second diffracted light converges at the third silicon wafer to generate interference fringes. The third silicon wafer moves along the X-direction following the XY two-dimensional displacement platform. The intensity of the interference signal received by the first radiation detector changes periodically in a sinusoidal manner. Every time the third silicon wafer moves a distance of the first crystal plane spacing along the X-direction, the interference signal changes by one period. The number of periods of the received interference signal is multiplied by the spacing of the crystal planes participating in diffraction along the X-direction to obtain the displacement of the third silicon wafer along the X-direction.

[0014] Optionally, the measurement principle of the displacement measurement module in the Y direction specifically includes:

[0015] The rays emitted by the second ray source are incident on the second crystal plane of the first silicon wafer at a Bragg angle and undergo Laue diffraction, and are divided into two beams of third diffracted light. The two beams of third diffracted light are incident on the second silicon wafer and undergo Laue diffraction again, thereby generating fourth diffracted light. The fourth diffracted light converges at the third silicon wafer to generate interference fringes. The third silicon wafer moves along the Y direction following the XY two-dimensional displacement platform. The intensity of the interference signal received by the second radiation detector varies periodically in a sinusoidal manner. Every time the third silicon wafer moves a distance of the second crystal plane spacing along the Y direction, the interference signal changes by one period. The number of periods of the received interference signal is multiplied by the spacing of the crystal planes participating in diffraction along the Y direction to obtain the displacement of the third silicon wafer along the Y direction.

[0016] Optionally, the target material of the first ray source is a Cu target, and the wavelength of the excited ray is 0.154 nm.

[0017] Optionally, the target material of the second ray source is a Cu target, and the wavelength of the excited ray is 0.154 nm.

[0018] Optionally, the target material of the first ray source is a molybdenum target, and the wavelength of the excited ray is 0.071 nm.

[0019] Optionally, the target material of the second ray source is a molybdenum target, and the wavelength of the excited ray is 0.071 nm.

[0020] Optionally, the crystal plane of the first silicon wafer is any one of a {220} crystal plane, a {111} crystal plane / {100} crystal plane, a {010} crystal plane / {100} crystal plane, a {001} crystal plane / {100} crystal plane, and a {011} crystal plane.

[0021] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0022] The invention provides a self-traceable two-dimensional displacement measuring device, comprising: a first ray source, a second ray source, a wafer fixing plate, a first silicon wafer, a second silicon wafer, a third silicon wafer, a first radiation detector, a second radiation detector and an XY two-dimensional displacement platform; the crystal plane of the first silicon wafer is a first crystal plane and a second crystal plane perpendicular to each other; the first ray source and the first silicon wafer, the second silicon wafer, the third silicon wafer and the first radiation detector constitute a displacement measuring module in the X direction; the second ray source and the first silicon wafer, the second silicon wafer, the third silicon wafer and the second radiation detector constitute a displacement measuring module in the Y direction; the first silicon wafer and the second silicon wafer are fixed on the wafer fixing plate in parallel; the third silicon wafer is parallel to the second silicon wafer, and the distance between the third silicon wafer and the second silicon wafer is equal to the distance between the first silicon wafer and the second silicon wafer; the third silicon wafer is fixed on the side wall of the XY two-dimensional displacement platform; the XY two-dimensional displacement platform drives the third silicon wafer to move together, and during the displacement process, the third silicon wafer and the second silicon wafer remain parallel and the distance remains unchanged. The present invention can simultaneously realize two-dimensional displacement measurement. At the same time, because the spacing of the crystal planes themselves is at the sub-nanometer level, and the measuring device is based on the crystal plane spacing, its measurement resolution can also reach the sub-nanometer level, and the measurement results can be directly traced back to the definition of meters. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of the overall structure of a self-traceable two-dimensional displacement measurement device provided by one embodiment of the present invention.

[0025] Figure 2A schematic diagram of the X-direction displacement measurement principle provided by an embodiment of the present invention.

[0026] Figure 3 A schematic diagram of the Y-direction displacement measurement principle provided by an embodiment of the present invention.

[0027] Reference numerals:

[0028] 101 - a first radiation source, 102 - a second radiation source, 201 - a wafer fixing plate, 202 - a first silicon wafer, 203 - a second silicon wafer, 3 - a third silicon wafer, 401 - a first radiation detector, 402 - a second radiation detector, 5 - an XY two-dimensional displacement platform. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] In an exemplary embodiment, Figure 1 As shown, a self-traceable two-dimensional displacement measuring device is provided, and the self-traceable two-dimensional displacement measuring device includes: a first ray source 101, a second ray source 102, a wafer fixing plate 201, a first silicon wafer 202, a second silicon wafer 203, a third silicon wafer 3, a first radiation detector 401, a second radiation detector 402 and an XY two-dimensional displacement platform 5; the crystal planes of the first silicon wafer 202 are first and second crystal planes that are perpendicular to each other.

[0032] The first ray source 101 , the first silicon wafer 202 , the second silicon wafer 203 , the third silicon wafer 3 , and the first radiation detector 401 constitute a displacement measurement module in the X direction.

[0033] The second ray source 102 , the first silicon wafer 202 , the second silicon wafer 203 , the third silicon wafer 3 , and the second radiation detector 402 constitute a displacement measurement module in the Y direction.

[0034] The first silicon wafer 202 and the second silicon wafer 203 are fixed in parallel on the wafer fixing plate 201; the third silicon wafer 3 is parallel to the second silicon wafer 203 (i.e., between the first silicon wafer 202, the second silicon wafer 203 and the third silicon wafer 3, the three wafers are parallel in pairs), and the distance from the third silicon wafer 3 to the second silicon wafer 203 is equal to the distance from the first silicon wafer 202 to the second silicon wafer 203.

[0035] The third silicon wafer 3 is fixed to the side wall of the XY two-dimensional displacement platform 5; the XY two-dimensional displacement platform 5 drives the third silicon wafer 3 to move together, and during the displacement process, the third silicon wafer 3 and the second silicon wafer 203 remain parallel and the distance between them remains unchanged.

[0036] As an optional implementation, the planar size, thickness and crystal orientation of the first silicon wafer 202 and the second silicon wafer 203 are completely consistent.

[0037] As an optional implementation, the size of the third silicon wafer 3 is larger than the size of the first silicon wafer 202 and the second silicon wafer 203. The specific size is not limited and is affected by the measurement range. If a larger measurement range is required, the size of the third silicon wafer 3 can be appropriately increased.

[0038] As an optional implementation, the target materials of the first ray source 101 and the second ray source 102 are Cu targets, and the wavelength of the excited rays is 0.154 nm.

[0039] It should be noted that the target materials of the first ray source 101 and the second ray source 102 are not limited to Cu targets, but may also be molybdenum targets, whose excited ray wavelength is 0.071 nm, or other target materials and excited ray wavelengths. The selection of the ray source wavelength mainly depends on the absorption of the silicon crystal to the ray of the wavelength and the intensity of the diffracted light.

[0040] As an optional implementation, the crystal plane of the first silicon wafer 202 is any one of the {220} crystal plane, the {111} crystal plane / {100} crystal plane, the {010} crystal plane / {100} crystal plane, the {001} crystal plane / {100} crystal plane, and the {011} crystal plane.

[0041] It should be noted that, in addition to the crystal planes of the silicon wafers listed above, other mutually perpendicular crystal planes can also be selected to achieve the two-dimensional displacement measurement described in the present invention. Since the {220} crystal plane and the {111} crystal plane have higher diffraction light intensity, the {220} crystal plane and the {111} crystal plane are selected as the crystal planes of the first silicon wafer 202 in this embodiment.

[0042] like Figure 2As shown, the measurement principle of the displacement measurement module in the X direction specifically includes:

[0043] The rays emitted by the first ray source 101 are incident on the first crystal plane of the first silicon wafer 202 at a Bragg angle and undergo Laue diffraction, and are divided into two beams of first diffracted light. The two beams of first diffracted light are incident on the second silicon wafer 203 and undergo Laue diffraction again, thereby generating second diffracted light. The second diffracted light converges at the third silicon wafer 3 to generate interference fringes. The third silicon wafer 3 moves along the X-direction following the XY two-dimensional displacement platform 5. The intensity of the interference signal received by the first radiation detector 401 varies periodically in a sinusoidal manner. Every time the third silicon wafer 3 moves a distance of the first crystal plane spacing along the X-direction, the interference signal changes by one period. The number of periods of the received interference signal is multiplied by the spacing of the crystal planes participating in diffraction along the X-direction to obtain the displacement of the third silicon wafer 3 along the X-direction.

[0044] Specifically, the Cu target ray emitted by the first ray source 101 enters the first silicon wafer 202 at a Bragg angle. The wavelength of the Cu target ray is 0.154 nm. The spacing between the {220} crystal planes of silicon is 0.19202 nm. According to the Bragg equation d sinθ=nλ(d is the grid spacing, is the incident angle, n is the diffraction order, and is the wavelength of the incident light). The incident angle is calculated to be 23.641°. (In this formula, when the wavelength of the ray source and the silicon lattice spacing are fixed, n is 1. Constructive interference can only occur when the corresponding calculated incident angle is satisfied. In the case of other incident angles, the intensity of the diffracted light will be affected. The incident angle is only a necessary condition for diffraction to occur. When the displacement is finally calculated, it is only related to the spacing of the 220 crystal planes.) Laue diffraction occurs at the first silicon wafer 202 and is divided into two beams of first diffracted light. The two beams of first diffracted light are incident on the second silicon wafer 203 and Laue diffracted again to generate second diffracted light. The second diffracted light converges at the third silicon wafer 3 to generate interference fringes. The third silicon wafer 3 moves along the X direction following the two-dimensional displacement platform 5. The intensity of the interference signal received by the first radiation detector 401 changes periodically in a sinusoidal manner. The interference signal changes by one period every time the third silicon wafer 3 moves a distance of one crystal plane spacing along the X direction. By calculating the number of cycles of the received signal and multiplying it by the spacing of the silicon {220} crystal planes, the displacement of the third silicon wafer 3 along the X direction can be obtained.

[0045] like Figure 3 As shown, the measurement principle of the displacement measurement module in the Y direction specifically includes:

[0046] The rays emitted by the second ray source 102 are incident on the second crystal plane of the first silicon wafer 202 at a Bragg angle and undergo Laue diffraction, and are divided into two beams of third diffracted light. The two beams of third diffracted light are incident on the second silicon wafer 203 and undergo Laue diffraction again, thereby generating fourth diffracted light. The fourth diffracted light converges at the third silicon wafer 3 to generate interference fringes. The third silicon wafer 3 moves along the Y direction following the XY two-dimensional displacement platform 5. The intensity of the interference signal received by the second radiation detector 402 varies periodically in a sinusoidal manner. Every time the third silicon wafer 3 moves a distance of the second crystal plane spacing along the Y direction, the interference signal changes by one period. The number of periods of the received interference signal is multiplied by the spacing of the crystal planes participating in diffraction along the Y direction to obtain the displacement of the third silicon wafer 3 along the Y direction.

[0047] Specifically, the Cu target ray emitted by the first radiation source 102 enters the first silicon wafer 202 at a Bragg angle, the wavelength of the Cu target ray is 0.154 nm, the spacing of the silicon {111} crystal planes is 0.31356 nm, and the incident angle is calculated to be 14.215° according to the Bragg equation dsinθ=nλ. Laue diffraction occurs at the first silicon wafer 202 and is divided into two third diffracted lights. The two third diffracted lights enter the second silicon wafer 203 and undergo Laue diffraction again to generate fourth diffracted lights. The fourth diffracted lights converge at the third silicon wafer 3 to generate interference fringes. The third silicon wafer 3 moves along the Y direction following the two-dimensional displacement platform 5. The intensity of the interference signal received by the second radiation detector 402 changes periodically in a sinusoidal law. The interference signal changes by one period when the third silicon wafer 3 moves along the Y direction by one crystal plane spacing. By calculating the number of periods of the received signal and multiplying it by the spacing of the silicon {111} crystal planes, the displacement of the third silicon wafer 3 along the Y direction can be obtained.

[0048] Compared with the prior art, the characteristics and beneficial effects of the present invention are:

[0049] (1) It can simultaneously realize two-dimensional displacement measurement, with a measurement resolution of sub-nanometer level, and the measurement results can be directly traced back to the definition of meter (because the spacing of the 220 crystal planes is 0.225nm, which is at the sub-nanometer level, and this measurement method is based on the 220 silicon crystal plane spacing, so its measurement resolution can also reach the sub-nanometer level, and the spacing of other silicon crystal planes is also at the sub-meter level) (In 2018, the 26th International Conference on Metrology proposed to use the silicon {220} crystal plane spacing as a way to reproduce the definition of meter).

[0050] (2) The spatial structure is compact. Two sets of radiation sources and radiation detectors share a set of silicon chips to achieve two-dimensional displacement measurement, which effectively improves space utilization.

[0051] (3) The measuring range is large. The third silicon wafer is designed to be separate from the first and second silicon wafers. The measuring range of the device depends on the motion range of the XY two-dimensional displacement measuring platform and has a large measuring range.

[0052] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A self-traceable two-dimensional displacement measurement device, characterized in that: The self-traceable two-dimensional displacement measuring device comprises: a first ray source, a second ray source, a wafer fixing plate, a first silicon wafer, a second silicon wafer, a third silicon wafer, a first radiation detector, a second radiation detector and an XY two-dimensional displacement platform; the crystal plane of the first silicon wafer is a first crystal plane and a second crystal plane that are perpendicular to each other; The first ray source, the first silicon wafer, the second silicon wafer, the third silicon wafer and the first radiation detector constitute a displacement measurement module in the X direction; The second ray source, the first silicon wafer, the second silicon wafer, the third silicon wafer and the second radiation detector constitute a displacement measurement module in the Y direction; The first silicon wafer and the second silicon wafer are fixed in parallel on the wafer fixing plate; the third silicon wafer is parallel to the second silicon wafer, and the distance from the third silicon wafer to the second silicon wafer is equal to the distance from the first silicon wafer to the second silicon wafer; The third silicon wafer is fixed to the side wall of the XY two-dimensional displacement platform; the XY two-dimensional displacement platform drives the third silicon wafer to move together, and during the displacement process, the third silicon wafer and the second silicon wafer remain parallel and the distance between them remains unchanged.

2. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that: The planar size, thickness and crystal orientation of the first silicon wafer and the second silicon wafer are completely consistent.

3. The self-traceable two-dimensional displacement measuring device according to claim 2, characterized in that: The third silicon wafer has a size greater than that of the first silicon wafer and the second silicon wafer.

4. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that: The measurement principle of the displacement measurement module in the X direction specifically includes: The rays emitted by the first ray source are incident on the first crystal plane of the first silicon wafer at a Bragg angle and undergo Laue diffraction, and are divided into two beams of first diffracted light. The two beams of first diffracted light are incident on the second silicon wafer and undergo Laue diffraction again, thereby generating second diffracted light. The second diffracted light converges at the third silicon wafer to generate interference fringes. The third silicon wafer moves along the X-direction following the XY two-dimensional displacement platform. The intensity of the interference signal received by the first radiation detector changes periodically in a sinusoidal manner. Every time the third silicon wafer moves a distance of the first crystal plane spacing along the X-direction, the interference signal changes by one period. The number of periods of the received interference signal is multiplied by the spacing of the crystal planes participating in diffraction along the X-direction to obtain the displacement of the third silicon wafer along the X-direction.

5. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that: The measurement principle of the displacement measurement module in the Y direction specifically includes: The rays emitted by the second ray source are incident on the second crystal plane of the first silicon wafer at a Bragg angle and undergo Laue diffraction, and are divided into two beams of third diffracted light. The two beams of third diffracted light are incident on the second silicon wafer and undergo Laue diffraction again, thereby generating fourth diffracted light. The fourth diffracted light converges at the third silicon wafer to generate interference fringes. The third silicon wafer moves along the Y direction following the XY two-dimensional displacement platform. The intensity of the interference signal received by the second radiation detector varies periodically in a sinusoidal manner. Every time the third silicon wafer moves a distance of the second crystal plane spacing along the Y direction, the interference signal changes by one period. The number of periods of the received interference signal is multiplied by the spacing of the crystal planes participating in diffraction along the Y direction to obtain the displacement of the third silicon wafer along the Y direction.

6. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that: The target material of the first ray source is a Cu target, and the wavelength of the excited ray is 0.154 nm.

7. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that: The target material of the second ray source is a Cu target, and the wavelength of the excited ray is 0.154 nm.

8. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that: The target material of the first ray source is a molybdenum target, and the wavelength of the excited ray is 0.071 nm.

9. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that: The target material of the second ray source is a molybdenum target, and the wavelength of the excited ray is 0.071 nm.

10. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that: The crystal plane of the first silicon wafer is any one of a {220} crystal plane, a {111} crystal plane / {100} crystal plane, a {010} crystal plane / {100} crystal plane, a {001} crystal plane / {100} crystal plane, and a {011} crystal plane.

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