JP2022529608A - Measurement system and light diffraction method - Google Patents

Abstract

The embodiments of the present disclosure relate to measurement systems and methods for diffracting light. The measurement system includes a stage, an optical arm, and one or more detector arms. A light diffraction method is provided, in which a light beam having a wavelength λlaser is projected onto a first zone of a first substrate with a fixed beam angle θ0 and a maximum orientation angle φmax, and a displacement angle Δθ. To determine the target maximum beam angle θt-max, which is θt-max = θ0 + Δθ, and to determine the target maximum beam angle θt-max, and the modified lattice pitch equation Pt-grating = It includes determining the test lattice pitch Pt-grating by λlaser / (sinθt-max + sinθ0). Measuring systems and methods allow the measurement of non-uniform properties in the region of the optics, such as grid pitch and grid orientation. [Selection diagram] FIG. 1A

Description

[0001] The embodiments of the present disclosure relate to devices and methods, and more specifically to measurement systems and methods that diffract light.

[0002] Virtual reality generally refers to a computer-generated simulated environment as if the user actually exists. The virtual reality experience is generated in 3D and displays a virtual reality environment that replaces the actual environment by viewing it on a head-mounted display (HMD) such as eyeglasses or another wearable display device with a near-eye display panel as a lens. be able to.

However, in augmented reality, the experience is that the user can see the image of the virtual object generated for the display as part of the environment while looking at the surrounding environment through the display lens of the glasses or other HMD device. Is possible. Augmented reality can include virtual images, graphics, video, etc. that enhance or enhance the environment the user experiences, as well as all types of inputs such as voice and tactile inputs. In order to realize an augmented reality experience, it is necessary to superimpose a virtual image on the surrounding environment, and the superimposition is performed by an optical device.

One of the drawbacks in the art is that the manufactured optics tend to have non-uniform characteristics such as grid pitch and grid orientation (grid direction). Also, the deposited optics may inherit the non-uniformity of the boards, such as local warpage and deformation of the boards. Further, if the substrate is deposited on the substrate arranged on the support surface having irregularities such as defects or particles on the support surface, the substrate may be tilted, and the deposited optical device may inherit the strain.

Therefore, what is needed in the art is a device and a method for detecting the non-uniformity of the optical device.

In one embodiment, a measurement system comprising a stage, an optical arm coupled to an arm actuator configured to scan the optical arm and rotate the optical arm about an axis, and a detector arm. Provided. The stage has a substrate support surface. The stage is coupled to a stage actuator configured to move the stage along a scanning path and rotate the stage about an axis. The optical arm includes a laser positioned adjacent to a beam splitter located in the optical path adjacent to the optical detector, and the laser beam splitters a light beam deflected at a beam angle θ along the optical path to the stage. It can be operated to project to. The detector arm includes a detector actuator configured to scan the detector arm and rotate the detector arm about an axis, a first focusing lens, and a detector.

In another embodiment, a stage, an optical arm coupled to an arm actuator configured to scan the optical arm and rotate the optical arm about an axis, and a first detector arm. A measurement system including a second detector arm is provided. The stage has a substrate support surface. The stage is coupled to a stage actuator configured to move the stage along a scanning path and rotate the stage about an axis. The optical arm includes a laser positioned adjacent to a beam splitter located in the optical path adjacent to the optical detector, and the laser beam splitters a light beam deflected at a beam angle θ along the optical path to the stage. It can be operated to project to. Each detector arm includes a detector actuator configured to scan the detector arm, a first focusing lens, and a detector.

In yet another embodiment, a light beam having a wavelength λ _laser is projected onto the first zone of the first substrate with a fixed beam angle θ ₀ and a maximum orientation angle (maximum direction angle) φ _max . To obtain the displacement angle Δθ and to determine the target maximum beam angle θ _{t-max ,} and to determine the target maximum beam angle θ t-max where θ _t-max = θ ₀ + Δθ. , Modified grid pitch equation P _t-grating = λ _laser / (sinθ _t-max + sinθ ₀ ) provides a method of diffracting light, including determining the test grid pitch P _t-grating .

The measuring system and measuring method measures local non-uniformity in the region of the optical device, such as grid pitch and grid orientation. The value of local non-uniformity helps to evaluate the performance of the optics.

The present disclosure summarized above will be described more specifically with reference to embodiments, some of which are exemplified in the accompanying drawings, so that the features of the present disclosure described above can be understood in detail. However, it should be noted that the accompanying drawings merely represent typical embodiments and therefore should not be considered as limiting the scope of the embodiments, and other equally valid embodiments may be tolerated. ..

It is a schematic diagram which shows the structure of the measurement system which concerns on some Embodiments. It is a schematic diagram which shows the structure of the measurement system which concerns on some Embodiments. It is a schematic diagram which shows the structure of the measurement system which concerns on some Embodiments. A to C are schematic views showing beam position detectors according to some embodiments. It is a schematic sectional drawing which shows the 1st zone which concerns on one Embodiment. FIG. 6 is a schematic diagram showing a measurement system including one or more detector arms according to some embodiments. FIG. 6 is a schematic diagram showing a measurement system including one or more detector arms according to some embodiments. FIG. 6 is a schematic diagram showing a measurement system including one or more detector arms according to some embodiments. FIG. 6 is a schematic diagram showing a measurement system including one or more detector arms according to some embodiments. It is a flow chart of the light diffraction method process which concerns on one Embodiment.

For ease of understanding, the same reference numbers are used to indicate the same elements in common in the drawings wherever possible. It is believed that the elements and features of one embodiment may be beneficially incorporated into other embodiments without further detailing.

The embodiments of the present disclosure relate to measurement systems and methods for measuring local non-uniformity of optical devices. The measurement system includes a stage, an optical arm, and one or more detector arms including one or more focusing lenses. The light projected from the optical arm is reflected by the substrate arranged on the stage, and the reflected light from the surface of the substrate is incident on the detector. The deflection from the optical center of the condensing lens is used to determine the local non-uniformity of the optics. The method of diffracting light includes measuring a scattered light beam from the surface of the substrate, and local strain is obtained from the measured value. The embodiments disclosed herein may be particularly useful, but not limited to, for measuring the local uniformity of optical systems.

As used herein, the term "about" means a +/- 10% variation from the nominal value. It should be understood that the above variations may be included in any of the values presented herein.

FIG. 1A is a schematic view showing a first configuration 100A of the measurement system 101 according to the embodiment. As illustrated, the measurement system 101 includes a stage 102, an optical arm 104A, and one or more detector arms 150. The measurement system 101 is configured to diffract the light generated by the optical arm 104. The light generated by the optical arm 104 is directed at the substrate placed on the stage 102, and the diffracted light is incident on one or more detector arms 150.

As shown, the stage 102 includes a support surface 106 and a stage actuator 108. The stage 102 is configured to hold the substrate 103 on the support surface 106. The stage 102 is coupled to the stage actuator 108. The stage actuator 108 is configured to move the stage 102 along the scanning path 110 along the X and Y directions and rotate the stage 102 about the Z axis. The stage 102 is configured to move and rotate the substrate 103 such that the light from the optical arm 104A is incident on different parts or regions of the substrate 103 during the operation of the measurement system 101.

The substrate 103 includes one or more optics 105 having one or more regions 107 of the grid 109. Each region 107 has a grid 109 with an orientation angle φ and a pitch P (FIG. 3), where P is between adjacent points, such as the center of mass of the adjacent first edge 301 or the adjacent grid 109. Defined as a distance. The pitch P and orientation angle φ of the grid 109 in the first region 111 may be different from the pitch P and orientation angle φ of the grid 109 in the second region 113 of one or more regions 107. In addition, local warpage or other deformation of the substrate 103 may cause local fluctuations in pitch P'and local orientation angle φ'. The measuring system 101 can be used to measure the pitch P and the orientation angle φ of the grid 109 for each of the regions 107 of each optical device 105. The substrate 103 can be a single crystal wafer of any size, such as having a radius of about 150 mm to about 450 mm. As shown, the light beam 126A from the optical arm 104A scatters from the region 107 to form the initial _R0 beam 450, which will be described in detail below.

The optical arm 104, the detector arm 150, and the stage 102 are coupled to the controller 130. The controller 130 facilitates control and automation of the method of measuring the pitch P and the orientation angle φ of the grid 109 described herein. The controller may include a central processing unit (CPU) (not shown), a memory (not shown), and a support circuit (or I / O) (not shown). The CPU is optional, used in industry to control various processes and hardware (eg, motors and other hardware), and to monitor processes (eg, transfer device location and scan time, etc.). It can be one of the computer processors in the form of. The memory (not shown) is connected to the CPU and can be an easily available memory such as a random access memory (RAM). Software instructions and data can be encoded, stored in memory, and instructed by the CPU. Further, a support circuit (not shown) for supporting the processor by the conventional method is also connected to the CPU. The support circuit may include a conventional cache, power supply, clock circuit, input / output circuit, subsystem, and the like. A program (or computer instruction) readable by the controller determines the tasks that can be performed on the board 103. The program may be software readable by the controller and may include code that monitors and controls, for example, the position of the substrate, the position of the optical arm, and the like.

As shown, the optical arm 104A includes a white light source 114A, a first beam splitter 116A, a second beam splitter 118A, a laser 120, a detector 122, and a spectroscope 124. The white light source 114 can be a fiber-coupled light source. The first beam splitter 116A is located in the optical path 126A adjacent to the white light source 114. According to one embodiment, the white light source 114 can operate so as to project white light at a beam angle θ along the optical path 126A to the substrate 103. The laser 120 can be a fiber-coupled light source. The laser 120 is positioned adjacent to the first beam splitter 116A. The laser 120 can operate to project a light beam having a wavelength onto the first beam splitter 116A so that the light beam is deflected at a beam angle θ along the optical path 126A to the substrate 103. The second beam splitter 118A is arranged in the optical path 126A adjacent to the first beam splitter 116A. The second beam splitter 118A can be operated so as to deflect the light beam reflected by the substrate 103 to the detector 122. The spectroscope 124 is coupled to the detector 122 and determines the wavelength of the light beam deflected by the detector 122. The light beam described herein can be a laser beam. The optical arm 104 sends a light beam along the optical path 126 so that the light is deflected by the substrate 103 and measured by one or more detector arms 150.

FIG. 1B is a schematic diagram showing a second configuration 100B of the measurement system 101 according to the embodiment. As shown, the optical arm 104B includes a laser 120, a beam splitter 128, and a beam position detector 132. The beam position detector 132 may include an image sensor such as a CCD or CMOS sensor. The beam splitter 128 is positioned in the optical path 126B adjacent to the beam position detector 132. The laser 120 is positioned adjacent to the beam splitter 128. The laser 120 can operate to project a light beam having a wavelength onto the beam splitter 128 so that the light beam is deflected at a beam angle θ along the optical path 126B to the substrate 103. According to one embodiment, the optical arm 104B includes a polarizing element 156 such as a half-wave plate and a quarter-wave plate 158. The splitter 156 is between the laser 120 and the beam splitter 128. The splitter 156 maximizes the efficiency of the light beam deflected by the beam splitter 128 at a beam angle θ. The quarter wave plate 158 is located in the optical path 126B and is positioned adjacent to the beam splitter 128. The quarter wave plate 158 maximizes the efficiency with which the light beam reflected by the substrate 103 reaches the beam position detector 132 and reduces the light beam reflected by the laser 120.

FIG. 1C is a schematic diagram showing a third configuration 100C of the measurement system 101 according to the embodiment. The optical arm 104C includes lasers 134a, 134b, ... 134n (collectively referred to as "plural lasers 134") and beam splitters 136a, 136b, ... 136n (collectively "plural beam splitters 136"). ) And. The plurality of beam splitters 136 are positioned adjacent to the beam position detector 132 and adjacent to each other in the optical path 126C. The laser 134a is configured to project a light beam having a first wavelength onto a beam splitter 136a so that the light beam having the first wavelength is deflected at a beam angle θ along the optical path 126c to the substrate 103. Has been done. The laser 134b is configured to project a light beam having a second wavelength onto a beam splitter 136b so that the light beam having a second wavelength is deflected at a beam angle θ along the optical path 126c to the substrate 103. Has been done. The laser 134n is configured to project a light beam having a third wavelength onto a beam splitter 136n so that the light beam having a third wavelength is deflected at a beam angle θ along the optical path 126C to the substrate 103. Has been done.

The optical arm 104C has a stator 156a, 156b, and so on. .. .. It may include 156n (collectively referred to as "plurality of modulators 156C") and a quarter wave plate 158. The plurality of splitters 156C are located between the plurality of lasers 134 and the plurality of beam splitters 136. The plurality of splitters 156C maximize the efficiency of the light beam deflected by the plurality of beam splitters 136 at the beam angle θ. The 1/4 wave plate 158 is located in the optical path 126C and is positioned adjacent to the beam splitter 136n. The 1/4 wave plate 158 maximizes the efficiency with which the light beam reflected by the substrate 103 reaches the beam position detector 132. The 1/4 wave plate 158 can be replaced according to the desired wavelength.

In any of the above configurations 100A, 100B, 100C, the optical arms 104A, 104B, 104C may include an arm actuator 112, in which the arm actuator rotates the optical arm 104 around the z-axis and z. It is configured to scan the optical arm in the direction. The optical arm 104 may be fixed during the measurement.

The beam position detector 132 of the second configuration 100B and the third configuration 100C can operate to determine the beam position of the light beam reflected by the substrate 103 to the beam position detector 132. FIG. 2A is a diagram showing a position sensitive detector 201A according to an embodiment, that is, a beam position detector 132 as a lateral sensor. FIG. 2B is a diagram showing the beam position detector 132 according to the embodiment as a four-quadrant sensor 201B. FIG. 2C is a diagram showing a beam position detector 132 as an image sensor array 201C, such as a charge-coupled device (CCD) array or a complementary metal oxide semiconductor (CMOS) array, according to some embodiments.

FIG. 4A is a schematic view showing the detector arm 150 according to the embodiment. As shown, the detector arm 150 includes a detector 410, a detector arm actuator 152, and a first focusing lens 401. The detector arm actuator 152 is configured to rotate the detector arm 150 about the z-axis and scan the detector arm 150 in the z-direction. In FIGS. 4A to 4D, the light from the optical path 126 is reflected by the region 107 of the substrate 103. This light is reflected by the initial _R0 beam 450 and is focused on the first _R0 beam 411 by the first focusing lens 401. The first _R0 beam 411 incident on the detector 410. The detector 410 is any optical device used in the art for detecting light, such as a CCD array or a CMOS array.

Prior to the measurement of region 107, the measurement system 101 may be calibrated on a known substrate 103 so that the detector arm 150 has a first _R0 beam 411 incident on the optical center 401c of the first focusing lens 401. Can be positioned to do. Both the measurement system 101 described above and below can be calibrated with a known substrate 103 as described herein. Due to the local distortion of the region 107, the initial _R0 beam 450 in the reference region 107 no longer enters the optical center 401c of the focusing lens 401. For example, there may be local warpage of the substrate 103 in region 107, or overall wafer tilt, wedges, warpage, deflection (bow), and the like. The presence of particles on the support surface may cause the substrate 103 to tilt on the support surface 106, and the particles arranged between the substrate 103 and the support surface increase the height of the region 107 with respect to the support surface. It causes local and / or overall distortion, such as region tilt (shown as tilted substrate 103t in FIGS. 4A-4D). In these cases with the tilted substrate 103t, the initial _R0 beam 450t is incident on the first focusing lens 401 at a first angle Δθ ₁ and the first _R0 beam 411t according to one embodiment. , The focus is on the part of the detector 410 that is about the _first delta distance Δ1 from the focused first _R0 beam 411 of the known substrate 103. The first delta distance Δ ₁ is obtained by Δ ₁ = f ₁ ^* tan (Δ θ ₁ ), and f ₁ is the focal length of the focusing lens 401. Thus, the _first delta distance Δ1 and the first angle Δθ ₁ can be used to obtain local strain information, as described in more detail below. According to one embodiment, the resolution of the detector 410 is _less than about Δ1.

FIG. 4B is a schematic view showing the detector arm 150 according to the embodiment. As shown, the detector arm 150 further includes a second focusing lens 402 and a third focusing lens 403. The initial _R0 beam 450t is incident on the first focusing lens 401 at an angle of Δθ ₁ , and the first focusing lens focuses the initial _R0 beam on the first _R0 beam 411t. The first _R0 beam 411t is incident on the second focusing lens 402, and the first focusing lens focuses the first _R0 beam on the second _R0 beam 412t. According to one embodiment, the second _R0 beam 412 is incident on the second incident spot on the third focusing lens 403, and the third focusing lens is known to have the second _R0 beam. Focused on the 3rd R ₀ beam 413t to the part of the detector 410 separated by the _2nd delta distance Δ2 from the focused 3rd R ₀ beam of the substrate, and Δ ₂ = Δ ₁ ^* f ₃ / f. ₂ , f ₂ is the focal length of the second focusing lens, and f ₃ is the focal length of the third focusing lens. Further, Δ ₂ = f ₃ ^* f ₁ ^* tan (Δ θ ₁ ) / f ₂ . Therefore, the _second delta distance Δ2 can be used to obtain local strain information through the first angle Δθ ₁ as described in more detail below. In some embodiments, the second delta distance Δ ₂ is greater than the first delta distance Δ ₁ because the detector is limited only by the magnitude of the second delta distance Δ ₂ . It is possible to use the detector 410 with a lower resolution. According to one embodiment, the resolution of the detector 410 is less _than about Δ2.

[0032] Although the three focusing lenses 401, 402, and 403 are included in the detector arm 150 as described above, it is considered that any number of focusing lenses can be used, and the lenses are measured by the detector 410. It can be configured as described above so that a larger delta distance is generated.

FIG. 4C is a schematic diagram showing a measurement system 101 including a first detector arm 150 and a second detector arm 150 ′ according to an embodiment. The first detector arm 150 is substantially similar to the detector arm described above in FIG. 4A. As shown, the second detector arm 150'includes a first focusing lens 401', a detector 410', and a detector actuator 152'. In this embodiment, the light following the optical path 126 is backscattered to generate a reflected _R1 beam 450t'. The second detector arm 150t'is located behind the optical arm 104, according to one embodiment, and the optical arm is at least partially transparent to the reflected _R1 beam 450t'.

[0034] According to one embodiment, the reflected R ₁ beam 450t'is a third focusing on the first focusing lens 401'with a _third delta distance Δ3 from the optical center 401c' of the first focusing lens. Incident to the spot, the first focusing lens focuses the reflected _R1 beam on the first _R1 beam 411t'. The third delta distance Δ ₃ is obtained by Δ ₃ = f ₁ ′ ^* tan (Δθ ₂ ), and f ₁ ′ is the focal length of the focusing lens 401 ′. Thus, the _third delta distance Δ3 and the second angle Δθ ₂ can be used to obtain local strain information, as described in more detail below. The resolution of the detector _410'is less than about Δ3 according to one embodiment. The displacement angle Δθ is determined by Δθ = Δθ ₂ -Δθ ₁ , and the displacement angle Δθ provides a local distortion of the pitch of the grid _Pt-grating , as described in more detail below.

FIG. 4D is a schematic diagram showing a measurement system 101 including a first detector arm 150 and a second detector arm 150 ′ according to an embodiment. The first detector arm 150 is substantially similar to the detector arm described above in FIG. 4B. As shown, the second detector arm 150'is a first focusing lens 401', a second focusing lens 402', a third focusing lens 403', a detector 410', and a detector actuator 152'. including. In this embodiment, the light following the optical path 126 is backscattered to generate a reflected _R1 beam 450t'. The second detector arm 150'is located behind the optical arm 104, according to one embodiment, and the optical arm is at least partially transparent to the reflected _R1 beam 450'.

According to one embodiment, the reflected R ₁ beam 450t'is a third focusing spot of the first focusing lens 401' with a _third delta distance Δ3 from the optical center 401c' of the first focusing lens. The first focusing lens focuses the reflected _R1 beam on the first _R1 beam 411t'. The first R ₁ beam 411t'is incident on the second focusing lens 402', and the first focusing lens focuses the first R ₁ beam on the second R ₁ beam 412 t'. The second _R1 beam 412t'is incident on the fourth focusing spot at the _fourth delta distance Δ4 from the optical center 403c' of the third focusing lens 403', and the third focusing lens is a known substrate. The second _R1 beam is focused on the third _R1 beam 413t'for the portion of the detector 410' that is separated from the focused third _R1 beam by a _fourth delta distance of about Δ4. In this way, the _fourth delta distance Δ4 can be used to obtain local strain information as in the _second delta distance Δ2.

[0037] In some embodiments, the _fourth delta distance Δ4 is greater than the _third delta distance Δ3, whereby the detector is limited only by the magnitude of the _fourth delta distance Δ4. Therefore, it becomes possible to use the detector 410', which has a lower resolution. The two delta distances Δ ₂ and Δ ₄ allow more detailed measurement of local strain in region 107. According to one embodiment, the _third delta distance Δ3 is larger than the _first delta distance Δ3. The resolution of the detector _410'is less than about Δ4 according to one embodiment. According to one embodiment, the focal length of the first focusing lens 401 of the first detector arm 150 is different from the focal length of the second focusing lens 402 of the first detector arm, and the first detection. The focal length of the second focusing lens of the instrument arm is different from the focal length of the third focusing lens 403 of the first detector arm.

4C-4D show a measurement system 101 with two detector arms 150, 150'with the same number of focusing lenses, but any odd number of lenses is used for each detector arm. Please understand what you can do. For example, the first detector arm 150 can have one focusing lens, the second detector arm 150'can have three focusing lenses, and vice versa. In another example, the first detector arm 150 has five focusing lenses and the second detector arm 150'has three focusing lenses.

In all of the above and following embodiments, Δ1, Δ2, _Δ3 , and _{Δ4 are} in the range of about 10 um to about ₁ mm, and Δθ ₁ , Δθ ₂ , Δθ ₃ , and Δθ ₄ are. , About 0.001 ° to about 1 °, for example, about 0.001 ° to about 0.1 °.

FIG. 5 is a flow chart of the light diffraction method 500 step according to the embodiment. Although the method steps are described in connection with FIG. 5, any system configured to perform the method steps in any order by one of ordinary skill in the art is described herein. You will understand that it falls within the scope of the form.

[0041] The method 500 is started in step 540, in which a light beam having a wavelength λ is projected onto a first region 107 of the first substrate 103 with a fixed beam angle θ ₀ and a maximum orientation angle φ _max . The method 500 may use any of the configurations 100A, 100B, 100C of FIGS. 1A-1C, 4A-4D of the measurement system 101, and any of the configurations of the detector arm 150. The white light source 114 projects white light at a fixed beam angle θ ₀ along the optical path 126A to the reference region 107, where the reference region 107 has one or more grids 109 and θ ₀ = arcsin (λ _laser / 2P). _Grating ), where P _grating is the design / average pitch of the grid.

In step 550, the displacement angle Δθ is acquired. According to some embodiments, the displacement angle Δθ is a _first angle Δθ ₁ in which Δθ ₁ is obtained by Δ ₁ = f ₁ ^* tan (Δθ ₁ ), and the displacement distance Δ1 measured as described above. Is equal to. In some embodiments, the displacement angle Δθ is determined by Δθ = Δθ ₂ -Δθ ₁ , and in the above equation, the second angle Δθ ₂ is Δ ₂ = f ₁ ^* f ₃ ^* tan, as described above. It is obtained by (Δθ ₂ ) / f ₂ .

In step 560, the stage 102 is rotated until the maximum initial intensity (initial I _max ) at the fixed beam angle θ ₀ is measured, and the maximum orientation angle φ _max is acquired. The maximum orientation angle φ _max corresponds to the orientation angle φ of one or more grids 109 in the reference region 107. The target maximum beam angle θ _t-max is calculated, and θ _t-max = θ ₀ + Δθ. In the calculation of the target maximum beam angle θ _t-max using Δθ, the overall distortion such as the overall inclination and warpage of the substrate is taken into consideration.

In step 570, the test grid pitch Pt _-grating is determined by the maximum orientation angle φ _max . To determine the initial pitch, project white light with a fixed beam angle θ ₀ and a maximum orientation angle φ _max , and solve the equation P _t-grating = P _grating + ΔP = λ _laser / (sin θ _t-max + sin θ ₀ ). That is included. Further, the measured pitch change ΔP is obtained as follows.

［００４５］

[0045]

The measured change in pitch ΔP can be from about 1 pm to about 5 nm.

[0047] In one embodiment, steps 540, 550, 560, and 570 are repeated. In step 570, the stage 102 is scanned along the scan path 110 and steps 540, 550, and 560 are repeated or subsequent with respect to subsequent zones of one or more regions 107 of one or more optical devices 105. Steps 540, 550 and 560 are repeated for the region. Further, by repeating the steps 540, 550, 560, and 570 after rotating the entire substrate 103 by about 180 ° about the z-axis, the entire wafer wedge can be measured.

[0048] As described above, devices and methods configured to measure the local non-uniformity of the optical device are included. The detector arm detects the reflected laser beam. The detector arm comprises one or more focusing lenses, one or more focusing lenses condensing light on a detector such as a camera. The displacement of the reflected light with respect to the test board is used to calculate the local non-uniformity that exists. It is possible to scan the substrate so that the non-uniformity of different regions of the substrate can be measured.

With this measurement system and method, it is possible to measure non-uniform characteristics of the optical device on the substrate, such as lattice pitch and lattice orientation. In addition, this measurement system and method can determine local warpage and deformation of the underlying substrate. Defects in the underlying support surface, such as particle imperfections, can also be positioned to determine if the substrate or optical device has acceptable properties. Measurements can be performed on substrates or optics of various sizes and shapes.

[0050] The aforementioned content is intended for embodiments of the present disclosure, but devises other further embodiments of the present disclosure without departing from its basic scope as determined by the claims below. It is possible.

Claims (15)

A stage having a substrate support surface and coupled to a stage actuator configured to move the stage in a scanning path and rotate the stage about an axis.
An optical arm coupled to an arm actuator configured to scan the optical arm and rotate the optical arm around the axis.
A laser positioned adjacent to a beam splitter located in an optical path adjacent to an optical detector, which projects a light beam deflected at a beam angle θ along the optical path to the stage onto the beam splitter. With an optical arm containing a laser that can work like
It ’s a detector arm,
A detector actuator configured to scan the detector arm and rotate the detector arm around the axis.
With the first condensing lens,
With the detector,
Including the detector arm and
A measurement system. The optical arm further
A white light source that can operate to project white light at the beam angle θ along the optical path to the stage.
A spectroscope coupled to the photodetector and determining the wavelength of the light beam deflected by the photodetector.
The measurement system according to claim 1. The optical arm further
A splitter positioned between the laser and the beam splitter,
A 1/4 wave plate positioned adjacent to the beam splitter in the optical path,
The measurement system according to claim 1. The light beam is reflected to become an initial _R0 beam, the initial _R0 beam is incident on the first focusing lens at a first incident spot, and the first incident spot is the first focused lens. The measurement system according to claim 1, wherein the measurement system is separated from the optical center of the lens by a _first delta distance of Δ1. The measuring system of claim 4, wherein the detector has a resolution of _less than about Δ1. The measurement system according to claim 4, further comprising a second focusing lens and a third focusing lens. The initial _R0 beam is focused on the first _R0 beam by the first focusing lens, and the first _R0 beam is focused on the second _R0 beam by the second focusing lens. The measurement system according to claim 6, wherein the second _R0 beam is focused on the third _R0 beam by the third focusing lens. The third _R0 beam is incident on the third focusing lens at the third incident spot.
The third incident spot is separated from the optical center of the third focusing lens by a _second delta distance Δ2, and the _second delta distance Δ2 is larger than the _first delta distance Δ1. big,
The measurement system according to claim 7. A stage having a substrate support surface and coupled to a stage actuator configured to move the stage in a scanning path and rotate the stage about an axis.
An optical arm coupled to an arm actuator configured to scan the optical arm and rotate the optical arm around the axis.
A laser positioned adjacent to a beam splitter located in an optical path adjacent to a photodetector, which projects a light beam deflected at a beam angle θ along the optical path to the stage onto the beam splitter. With a laser that can operate like
With an optical arm, including
The first detector arm and the second detector arm, respectively.
A detector actuator configured to scan the first detector arm or the second detector arm.
With the first condensing lens,
With the detector,
The first detector arm and the second detector arm including
A measurement system. The measuring system according to claim 9, wherein the second detector arm is arranged behind the optical arm. The light beam is reflected to become an initial _R0 beam, and the initial _R0 beam is incident on the first focusing lens of the first detector arm by the first incident of the first detector arm. Incident at the spot,
The first incident spot of the first detector arm is separated from the optical center of the first focusing lens of the first detector arm by a _first delta distance Δ1.
The light beam is reflected by a workpiece arranged on the stage to become a reflected _R1 beam, and the reflected _R1 beam is sent to the first focusing lens of the second detector arm and the second detector. Incident at the first incident spot on the arm,
The first incident spot of the second detector arm is separated from the optical center of the first focusing lens of the second detector arm by a _third delta distance Δ3.
The measurement system according to claim 10. It ’s a method of diffracting light.
Projecting a light beam with a wavelength λ _laser onto the first zone of the first substrate with a fixed beam angle θ ₀ and a maximum orientation angle φ _max .
Obtaining the displacement angle Δθ and
To determine the target maximum beam angle θ _{t-max ,} and to determine the target maximum beam angle θ t-max, where θ _t-max = θ ₀ + Δθ.
The test grid pitch P _-grating is determined by the modified grid pitch formula P _t-grating = λ _laser / (sinθ _t-max + sinθ ₀ ).
How to include. Projecting the light beam, acquiring the displacement angle Δθ, determining the target maximum beam angle θt _-max , and determining the test grid pitch _Pt-grating can be used in subsequent zones. 12. The method of claim 12, which is repeated. Acquiring the displacement angle Δθ means
The first incident spot is such that the initial _R0 beam is incident on the focusing lens at the first incident spot and the first incident spot is separated from the optical center of the focused lens by the _first delta distance Δ1. Reflecting the light beam in the zone to make it an initial _R0 beam,
Determining the _{first angle Δθ 1 from} the first delta distance Δ1 and
12. The method of claim 12. The _first angle Δθ ₁ is determined by using the equation Δ1 = f ₁ ^* tan (Δθ ₁ ), wherein f ₁ is the focal length of the focusing lens, according to claim 14. Method.

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