Disclosure of Invention
The invention provides a surface three-dimensional shape measuring device for a large-size wafer, and aims to solve the problem that the existing measuring system cannot meet the requirements of large-range measurement and high-precision measurement at the same time.
The embodiment of the invention provides a device for measuring the surface three-dimensional appearance of a large-size wafer, which comprises a base, a motion module and a support assembly which are arranged on the base, and an optical measurement module arranged on the motion module;
wherein, the support group is provided with a flat crystal and a wafer to be tested;
the optical measurement module comprises a support plate arranged on the motion module, a light-emitting component arranged on the support plate, a plano-convex lens component and a 90-degree off-axis parabolic mirror component which are sequentially arranged on an emergent light path of the light-emitting component, and a camera component for collecting interference fringe images formed by emergent light of the light-emitting component on the flat wafer and the wafer to be measured.
Preferably, the light emitting assembly includes: a helium-neon laser source and a light source holder therefor;
wherein, the light source support configuration is in on the backup pad, helium neon laser source is fixed on the light source support.
Preferably, the bracket assembly comprises: the device comprises a plurality of adjustable supporting bases arranged on the base, supporting rods respectively arranged on the plurality of supporting bases, and a flat crystal supporting frame arranged on the supporting rods.
Preferably, the motion module comprises: the walking device comprises a first-direction walking assembly and a second-direction walking assembly arranged on the first-direction walking assembly, wherein the second-direction walking assembly can move along with the first-direction walking assembly.
Preferably, the first direction walking assembly comprises: the device comprises a first guide rail arranged on the base, a first servo motor arranged on the first guide rail, a first screw rod connected with an output shaft of the first servo motor, and a first sliding block sleeved on the first screw rod.
Preferably, the second direction walking assembly comprises a second guide rail configured on the first sliding block, a second servo motor configured on the second guide rail, a second lead screw connected with an output shaft of the second servo motor, and a second sliding block sleeved on the second lead screw, wherein the supporting plate is fixed on the second sliding block.
Preferably, the support plate is an optical bread plate.
Preferably, the plano-convex lens assembly comprises: a plano-convex lens and a first lens holder;
wherein the first lens holder is disposed on the support plate, and the plano-convex lens is disposed on the first lens holder.
Preferably, the 90 ° off-axis parabolic mirror assembly comprises: a 90 degree off-axis parabolic mirror and a second lens holder;
wherein the second lens holder is disposed on the support plate, and the 90 ° off-axis parabolic mirror is disposed on the second lens holder.
Preferably, the camera assembly comprises: a camera, and a camera mount;
wherein the camera mount is disposed on the support plate and the camera is disposed on the camera mount.
According to the surface three-dimensional shape measuring device of the large-size wafer, the motion module is arranged on the base, the optical measuring module is arranged on the motion module, so that the optical measuring module moves along with the motion module on a preset moving path, the light emitting component emits parallel light rays and enters the plano-convex lens component, the plano-convex lens component focuses the parallel light rays into a point light source, the point light source entering at a focus can be changed into collimated light rays with the diameter size equal to the diameter size of the mirror surface to be emitted after the collimated light rays are emitted to the 90-degree off-axis parabolic mirror, and the measured surface with the diameter size of the mirror surface is directly covered to generate interference. And acquiring interference fringe images of the flat crystal and the measured surface through a camera assembly, and further solving the height information of the measured surface through solving the phase to restore the three-dimensional morphology. By adopting the structure and the measuring method based on the thin film interference principle, the influence of the motion error introduced by a large-stroke motion system on the measuring result can be reduced while the wavelength-level measuring precision of monochromatic light is met, and the problem that in the prior art, the measuring system cannot simultaneously meet the requirements of large-range measurement and high-precision measurement is solved.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the equipment or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
The following detailed description of specific embodiments of the invention refers to the accompanying drawings.
The invention discloses a surface three-dimensional shape measuring device for a large-size wafer, and aims to solve the problem that the existing measuring system cannot meet the requirements of large-range measurement and high-precision measurement at the same time.
Referring to fig. 1 and 2, an embodiment of the invention provides a device for measuring a three-dimensional surface topography of a large-sized wafer, which includes a base 1, a motion module 3 and a support assembly 4 disposed on the base 1, and an optical measurement module disposed on the motion module 3;
wherein, the flat crystal 5 and the wafer 6 to be tested are arranged on the bracket group;
the optical measurement module comprises a supporting plate 291 arranged on the motion module 3, a light emitting component arranged on the supporting plate 291, a plano-convex lens 24 component and a 90-degree off-axis parabolic mirror 25 component which are sequentially arranged on an emergent light path of the light emitting component, and a camera component for collecting interference fringe images formed by emergent light of the light emitting component on the flat crystal 5 and the wafer 6 to be measured.
In this embodiment, when facing a large-sized wafer, the movement module 3 drives the optical measurement module to move in a certain sequence, so that the carried optical measurement module collects interference fringe images of different areas to splice, and obtains a full-field interference fringe image, and a phase is obtained to further obtain the full-field topography of the surface of the wafer 6 to be measured.
Specifically, referring to fig. 2 and fig. 3, the parallel light emitted by the light emitting element is incident to the plano-convex lens 24 assembly, the plano-convex lens 24 assembly focuses the parallel light into a point light source and emits the point light to the 90 ° off-axis parabolic mirror 25 assembly, the 90 ° off-axis parabolic mirror 25 assembly changes the point light source incident at the focal point into collimated light with a diameter equivalent to the mirror surface diameter and emits the collimated light, according to the principle of thin film interference, two rows of light waves are reflected by the collimated light emitted by the 90 ° off-axis parabolic mirror 25 assembly on the lower surface (measured surface) of the measured wafer 6 and the upper surface (reference surface) of the flat crystal 5 to generate interference fringes by interference, and the optical path difference generated by the reflection of the incident light on two different surfaces of the measured surface and the reference surface is related to the change of the thickness of the thin film, that is, the change of the thickness of the thin film is caused by the change, and acquiring an interference fringe image through the camera assembly, and further solving the height information of the measured surface through solving the phase to restore the three-dimensional morphology. For a large-size wafer, the movement module 3 needs to move in a certain sequence, so that the carried measuring mechanism collects interference fringe images of different areas to be spliced, a full-field interference fringe image is obtained, and the phase is obtained, so that the full-field appearance of the surface of the wafer 6 to be measured is further obtained.
In this embodiment, the light emitting assembly includes: a helium-neon laser source 22 and a light source holder 21 therefor;
wherein the light source holder 21 is disposed on the support plate 291, and the helium-neon laser source 22 is fixed to the light source holder 21.
It should be noted that the he-ne laser source 22 is one of the most widely used lasers with the earliest operation time, the most mature technology, and is a gas laser, and gas atoms have a certain energy level structure, and are excited by external electrons to generate energy level transition, and generate excited radiation to emit laser, so that the he-ne laser wavelength is pure monochromatic light, the line width is extremely narrow, the wavelength error is only a few nanometers, and the he-ne laser has an extremely large coherence length. Some lasers that emit light by band transitions, such as LDs, are not comparable in monochromaticity and coherence. The atomic level structure is determined, and thus the laser is not affected by temperature fluctuation. The laser output has good collimation property due to the action of the resonant cavity, and the divergence angle is only a few milliradians. The helium-neon laser source 22 has incomparable advantages where good monochromatic light, coherence and collimation are required, particularly in the field of precision measurements.
In this embodiment, referring to fig. 4, the bracket assembly 4 includes: a plurality of adjustable support bases 43 disposed on the susceptor 1, support rods 42 disposed on the plurality of support bases, respectively, and a flat crystal support 41 disposed on the support rods 42.
It should be noted that, in this embodiment, 3 adjustable supporting bases 43 may be configured, and the supporting rods 42 are correspondingly configured, where the adjustable supporting bases 43 are used to adjust the supporting frame of the flat crystal 5, and in other embodiments, the number of the adjustable supporting bases 43 may be set according to actual situations, which is not specifically limited herein, but these schemes are within the protection scope of the present invention.
In this embodiment, the motion module 3 includes: a first direction running component 31 and a second direction running component 32 configured on the first direction running component 31, wherein the second direction running component 32 can move along with the first direction running component 31.
It should be noted that the first direction walking assembly 31 and the second direction walking assembly 32 are configured to drive the optical measurement module to move in a certain sequence, so that the carried optical measurement module collects interference fringe images of different areas to be spliced, so as to obtain a full-field interference fringe image.
In the present embodiment, the first direction walking assembly 31 includes: the device comprises a first guide rail arranged on the base 1, a first servo motor arranged on the first guide rail, a first screw rod connected with an output shaft of the first servo motor, and a first sliding block sleeved on the first screw rod.
It should be noted that an input end of the first servo motor may be connected to a controller, for example, a PLC controller, and is configured to receive a pulse signal output by the controller, and control rotation of the first servo motor to drive the first lead screw to rotate, so as to drive the first slider to move.
In this embodiment, the second direction moving assembly 32 includes a second guide rail disposed on the first slider, a second servo motor disposed on the second guide rail, a second lead screw connected to an output shaft of the second servo motor, and a second slider sleeved on the second lead screw, wherein the supporting plate 291 is fixed on the second slider.
It should be noted that an input end of the second servo motor may be connected to a controller, for example, a PLC controller, and configured to receive a pulse signal output by the controller, and control rotation of the second servo motor to drive the second lead screw to rotate, so as to drive the second slider and the support plate 291 fixed on the second slider to move. In other embodiments, the first direction walking assembly 31 and the second direction walking assembly 32 may also be formed by other devices, which are not specifically limited herein, but these solutions are all within the protection scope of the present invention.
In this embodiment, the supporting plate 291 may be an optical bread board.
It should be noted that, in other embodiments, the supporting plate 291 may be made of other materials, which is not specifically limited herein, but these solutions are all within the protection scope of the present invention.
In the present embodiment, the plano-convex lens 24 assembly includes: a plano-convex lens 24 and a first lens holder 23;
wherein the first lens holder 23 is disposed on the support plate 291, and the plano-convex lens 24 is disposed on the first lens holder 23.
It should be noted that the first lens holder 23 is used for fixing the plano-convex lens 24 in front of the light source, and at least partially receives the parallel light emitted from the light source.
In the present embodiment, the 90 ° off-axis parabolic mirror 25 assembly includes: a 90-degree off-axis parabolic mirror 25 and a second lens holder 26;
wherein the second lens holder 26 is disposed on the support plate 291, and the 90 ° off-axis parabolic mirror 25 is disposed on the second lens holder 26.
It should be noted that the second lens holder 26 is used to fix the 90 ° off-axis parabolic mirror 25 in front of the plano-convex lens 24, and at least partially receives the point light source emitted from the plano-convex lens 24.
In the present embodiment, the camera assembly includes: a camera 28, and a camera mount 29;
wherein the camera mount 29 is disposed on the support plate 291, and the camera is disposed on the camera mount 29.
It should be noted that the camera support 29 is used for fixing the camera 28, so that the camera 28 can capture an interference fringe image.
According to the surface three-dimensional shape measuring device of the large-size wafer, the motion module is arranged on the base, the optical measuring module is arranged on the motion module, so that the optical measuring module moves along with the motion module on a preset moving path, the light emitting component emits parallel light rays and enters the plano-convex lens component, the plano-convex lens component focuses the parallel light rays into a point light source, the point light source entering at a focus can be changed into collimated light rays with the diameter size equal to the diameter size of the mirror surface to be emitted after the collimated light rays are emitted to the 90-degree off-axis parabolic mirror, and the measured surface with the diameter size of the mirror surface is directly covered to generate interference. And acquiring interference fringe images of the flat crystal and the measured surface through a camera assembly, and further solving the height information of the measured surface through solving the phase to restore the three-dimensional morphology. By adopting the structure and the measuring method based on the thin film interference principle, the influence of the motion error introduced by a large-stroke motion system on the measuring result can be reduced while the wavelength-level measuring precision of monochromatic light is met, and the problem that in the prior art, the measuring system cannot simultaneously meet the requirements of large-range measurement and high-precision measurement is solved.
The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention.