Stacked piece curved surface deformation measuring device based on multi-contact micro-mirror and method

Abstract

The present invention relates to the related technical field of surface three-dimensional topography measurement. Disclosed are a stacked piece curved surface deformation measuring device based on a multi-contact micro-mirror and a method. The measuring device comprises a light source, an array mask, a light splitter, a reflecting mirror, a multi-contact micro-mirror, and a camera. The light splitter is arranged behind the light source, the array mask is arranged between the light splitter and the light source, the reflecting mirror and the multi-contact micro-mirror are both arranged behind the light splitter, and stacked pieces to be measured are arranged behind the multi-contact micro-mirror. The array mask is used for dividing, according to the distribution of a mask array, light emitted by the light source into multiple beams of parallel incident light, and one beam of light is used for measuring the curved surface deformation of a single stacked piece. A plurality of micro-mirrors are arranged at the front end of the multi-contact micro-mirror, and in the measurement process, a single micro-mirror extends into the position between adjacent stacked pieces to be measured for measurement. By means of the present invention, the problem of simultaneous measurement of curved surface deformation of the surfaces of a plurality of stacked pieces among stacked pieces is solved.

Description

Device and method for measuring deformation of stacked sheet surface based on multi-contact micro-mirrors

Technical field

[0001] The present invention belongs to the technical field related to surface three-dimensional topography measurement, and more specifically, relates to a device and method for measuring the deformation of a stacked sheet surface based on a multi-contact micro-mirror. [Background Technology]

[0002] There are many layers of stacked wafers. Under the influence of environmental stress such as high temperature and high pressure, the wafers will produce a certain degree of warping and bending. If this continues for a long time, the performance of the device will be greatly affected. At this time, it is necessary to accurately measure the changes in the surface morphology of each wafer in the stacked wafers in order to grasp the deformation of the device in real time and then predict the performance life of the device. The spacing between stacked wafers is generally a few microns to a few millimeters, and conventional technical means are difficult to measure such a small spacing. In addition to the current measurement problems of stacked wafers, stacked metal sheets, laser-processed metal gaps, laminated materials, and other objects stacked with small spacing will have this measurement problem. Therefore, a high-precision and high-efficiency measurement device and surface morphology fitting method are needed to solve the measurement problem of the stacked sheet gap.

[0003] Currently, gap measurement for metal materials is typically performed using a probe discharge method. This involves clicking a probe with an applied DC voltage to move radially. As the probe moves toward the object until a discharge occurs, the difference between the probe's travel distance and the initial installation gap is the gap distance. This method suffers from significant measurement errors and a limited measurement range, and is only suitable for conductive materials such as metals. However, existing conventional testing methods lack adequate measurement capabilities for the widespread nanoscale measurement of gaps between stacked sheets, which range from a few microns to several millimeters or even larger.

[0004] Therefore, a measurement system was developed that can accurately detect the deformation of the stacked sheets. The deformation of the stacked sheets can be measured and evaluated with high efficiency and high precision. The surface morphology of each thin sheet in the stacked sheets can be fitted using the measured data and algorithms. This is conducive to timely detection of morphological changes in the thin sheets in the stacked sheets, prediction of the performance life of the device, and improvement of the device's utilization efficiency.

[0005] [Summary of the invention]

[0006] In response to the above defects or improvement needs of the prior art, the present invention provides a stacked sheet surface deformation measurement device and method based on a multi-contact micro-mirror to solve the problem of simultaneously measuring the surface deformation of multiple stacked sheets in a stacked sheet.

[0007] To achieve the above-mentioned object, according to one aspect of the present invention, a device for measuring the deformation of a stacked sheet surface based on a multi-touch micro-mirror is provided. The device comprises a light source, an array mask, a spectrometer, a reflector, a multi-touch micro-mirror and a camera, wherein:

[0008] The beam splitter is arranged behind the light source, the array mask is arranged between the beam splitter and the light source, the reflector and the multi-contact micro-reflector are both arranged behind the beam splitter, and the stacked sheet to be tested is arranged behind the multi-contact micro-reflector;

[0009] The array mask is used to divide the light emitted by the light source into multiple beams of parallel incident light according to the distribution of the mask array, and one beam of light is used to detect the surface deformation of a stack of sheets to be tested. The front end of the multi-contact micro-reflector is provided with multiple micro-reflectors. During the measurement process, a single micro-reflector extends between adjacent stacked sheets to be tested for detection. The spacing between the micro-reflectors is set according to the gap between adjacent stacked sheets in the stack to be tested.

[0010] The light emitted by the light source is divided into several beams of parallel light by the pinhole array mask. For one of the beams of parallel light, the beam of parallel light is divided into two beams of light with different directions by the beam splitter. One beam enters the reflector as reference light, and the other beam enters a micro-reflector in the multi-contact micro-reflector as measurement light. The measurement light is reflected by the multi-contact micro-reflector and illuminates the surface of the stacked sheet to be measured, and is reflected by the stacked sheet to be measured. The reflected light returns to the beam splitter along the original path. At the same time, the reference light is reflected by the reflector and enters the beam splitter. Both the reference light and the measurement light are reflected by the beam splitter and enter the camera to merge, thereby forming an interference pattern.

[0011] Further preferably, the surface of the array mask has a linear array of pinholes, and the distance between the pinhole arrays corresponds to the contact pitch of the multi-contact micro-reflector.

[0012] Further preferably, the multi-contact micro-reflector comprises a substrate and a plurality of contacts arranged on the substrate, the substrate is made of a light-transmitting material, and the bottom surfaces of the contacts are in contact with the surface of the substrate.

[0013] Further preferably, the contact is a micro right-angle prism, the hypotenuse of which is a micro-reflector, and the light is incident from the side of the substrate and enters the micro-reflector from the right-angled edge of the micro right-angle prism. The light is reflected by the micro-reflector and illuminates the surface of the stacked sheet to be tested. The reflected light after reflection from the surface of the stacked sheet to be tested illuminates the micro-reflector and then returns along the original path.

[0014] Further preferably, the contact is a micro-channel prism, which includes two micro-channels, and the connection between the two channels is a right-angled slope, which is a micro-reflector. Light is incident from the bottom surface of the substrate into one of the micro-channels, reflected by the micro-reflector and then enters the other channel. After propagating in the other channel, it reaches the surface of the stacked sheet to be tested. The reflected light after reflection from the surface of the stacked sheet to be tested is irradiated on the micro-reflector and then returns along the original path.

[0015] Further preferably, the base includes a clamping portion and a transition portion, the clamping portion is used to clamp the contact, the transition portion is used to connect the contact and the clamping portion, and a micro-plane reflector is provided at the front end of the contact, and the micro-plane reflector is a micro-mirror.

[0016] Further preferably, the micro flat mirror is based on a brittle sheet material, the surface of which is coated with a silver film or an aluminum film, a layer of silicon dioxide protective film is attached to the surface of the silver film or the aluminum film, and the contact size is 1 um to 10 mm.

[0017] Further preferably, the stacked sheets to be tested are stacked sheet-like objects, including stacked semiconductor wafers, stacked metal sheets or stacked chips.

[0018] Further preferably, the measuring device also includes a first displacement stage, a second displacement stage and a third displacement stage. The first displacement stage is arranged below the reflector and is used to adjust the position of the reflector. The second displacement stage is arranged below the multi-contact micro-reflector and is used to adjust the position of the multi-contact micro-reflector. The third displacement stage is used to place the stacked sheet to be measured, and the rotation or movement of the third displacement stage drives the stacked sheet to be measured to rotate or move.

[0019] According to another aspect of the present invention, there is provided a method for performing measurement using the aforementioned measuring device, the method comprising the following steps:

[0020] S1 adjusts the positions of the reflector and the multi-contact micro-reflector so as to form a plurality of interference patterns in the camera; wherein each contact of the multi-contact micro-reflector is located between adjacent stacked sheets to be tested;

[0021] S2 calculates the distance between the reflection point of the light in the multi-contact micro-reflector and the reflection point of the light on the surface of the stacked sheet to be measured, that is, the elevation value at the reflection point on the surface of the stacked sheet to be measured;

[0022] S3 rotates the stacked sheet to be tested and records the rotation angle, and repeats steps S1 to S2 until the elevation values ​​of multiple reflection points on each surface of the stacked sheet to be tested are obtained;

[0023] S4 uses the elevation value of each reflection point and the rotation angle to fit all the multiple reflection points to obtain a surface curved surface of the stacked sheet to be tested, and determines whether the surface of the stacked sheet to be tested is deformed based on the fitted curved surface;

[0024] In step S3, the elevation is used to calculate the inclination angle of the reflection point. The inclination angle of the reflection point is calculated according to the following relationship:

[0025] Where h is the distance in the Y direction that the reflected light of the calculated light path in the camera is deflected relative to the reflected light of the reference light path, h1 is the distance from the point where the light beam is incident on the multi-contact micro-reflector to the reflection point of the stack to be measured, and l2 is the sum of the distances between the multi-contact micro-reflector and the beam splitter and the camera;

[0026] During fitting, the fitting method is also determined based on the inclination angle of the reflection point. If the inclination angle is less than the preset threshold, the two-dimensional Griddata interpolation algorithm is used for fitting; otherwise, the cubic polynomial fitting algorithm is used.

[0027] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0028] 1. The present invention uses a pinhole array mask and a multi-contact micro-mirror in combination. The array mask is used to split light into multiple beams. Each beam forms a separate interference pattern after passing through the subsequent beam splitter reflector and a single micro-mirror in the multi-contact micro-mirror. Multiple parallel beams can simultaneously measure multiple stacked wafer surfaces, achieving simultaneous measurement of multiple surfaces and improving measurement efficiency.

[0029] 2. The gaps between stacked sheets to be measured by this invention are narrow, typically ranging from a few microns to a few millimeters. Existing gap measurement methods primarily rely on mechanical probe conductivity measurement, which is very limited in measurement scenarios. This invention, based on optical measurement principles, uses multi-contact micromirrors to collect reflected light data from the stacked sheets and determine their deformation. This provides high measurement accuracy and broad applicability.

[0030] 3. The size of the micromirror contacts in the multi-contact micro-reflector of the present invention is generally 1 μm to 10 mm. This size is designed according to the gap between the stacked sheets to be measured, and is adapted to the measurement requirements of different gap distances between the stacked sheets. It corresponds to the design of the pinhole array mask, so that the parallel light emitted by it can accurately be incident on the contacts in each multi-contact micro-reflector, thereby measuring the surface deformation of each stacked sheet to be measured in the stacked sheet. When facing the measurement requirements of stacked sheets with different gaps, the measuring device only needs to replace the pinhole array mask and multi-contact micro-reflector corresponding to the gap size of the stacked sheets, thereby expanding the scope of use of the measuring device and improving the efficiency of the measuring device.

[0031] 4. The measurement method of the present invention is based on the principle of interference. Simply operating the measuring device can obtain the elevation data and angle data of multiple measurement points on each piece in the stack. The deformation of the measured stack can be obtained by using the two-dimensional Griddata interpolation algorithm and the cubic polynomial fitting algorithm. The measurement method is simple and reliable, with guaranteed accuracy and high repeatability.

Brief Description of the Drawings

[0032] FIG1 is a schematic diagram of a device for measuring curved surface deformation of stacked sheets constructed according to a preferred embodiment of the present invention;

[0033] FIG2 is a schematic diagram showing the principle of measuring the tilt angle of a reflection point of a stacked sheet constructed according to a preferred embodiment of the present invention;

[0034] FIG3 is a schematic structural diagram of a multi-contact micro-reflector constructed according to a preferred embodiment of the present invention;

[0035] FIG4 is a schematic structural diagram of a multi-contact micro-reflector constructed according to another preferred embodiment of the present invention;

[0036] FIG5 is a schematic structural diagram of a multi-contact micro-reflector constructed according to another preferred embodiment of the present invention;

[0037] FIG6 is a diagram showing the fitting result of the sheet torsional bending deformation surface constructed according to the preferred embodiment of the present invention;

[0038] FIG7 is a diagram showing the fitting results of the concave-convex curved deformation surface of the sheet constructed according to the preferred embodiment of the present invention.

[0039] In all the drawings, the same reference numerals are used to represent the same elements or structures, wherein: 1-light source, 2-array mask, 3-beam splitter, 4-first translation stage, 5-reflector, 6-reference light path, 7-camera, 8-second translation stage, 9-multi-contact micro-reflector, 10-measurement light path, 11-stacked sheet to be measured, 12-third translation stage, 13-clamping part, 14-contact, 15-transition part, 16-substrate, 17-micro-reflector, 18-single stacked sheet, 19-reflection point, 20-tangent line of the reflection point on the stacked sheet, 21-camera display, 22-light beam reflected from the reference light path into the camera, 23-light beam reflected from the measurement light path into the camera. [Specific implementation method]

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0041] As shown in FIG1 , a device for measuring the gap between stacked sheets includes: a light source 1, a pinhole array mask 2, a beam splitter 3, a first translation stage 4, a reflector 5, a second translation stage 8, and a multi-contact micro-reflector 9;

[0042] A beam splitter 3 connects a reference optical path 6 and a measurement optical path 10. The reference optical path 6 is located in the direction of the reflected optical path of the beam splitter 3 from the light source 1, while the measurement optical path 10 is located in the direction of the transmitted optical path of the beam splitter 3 from the light source 1. A first translation stage 4 is mounted on the reference optical path 6, carrying a reflector 5. The reflector 5 is used to reflect the light source 1 from the reference optical path 6 into the beam splitter 3. A second translation stage 8 is mounted on the measurement optical path 10, carrying a multi-contact micro-mirror 9. The multi-contact micro-mirror 9 is used to reflect the light source 1 from the measurement optical path 10 onto the stacked plate, and to reflect the reflected light from the stacked plate into the beam splitter 3. The stacked plate 11 to be measured is placed on a third translation stage 12, which rotates to rotate the stacked plate.

[0043] The multi-contact micro-mirror 9 can measure the interference signal from the micro-mirror to the wafer. Especially when the spacing between stacked wafers is generally a few microns to a few millimeters, the structure of the multi-contact micro-mirror 9 of the present invention can efficiently and accurately measure the deformation of each wafer in the stack.

[0044] The surface of the array mask 2 has a linear array of pinholes, and the distance between the pinhole arrays corresponds to the contact pitch of the multi-contact micro-mirrors.

[0045] The multi-contact micro-reflector 9 includes a substrate 16 and a plurality of contacts, and the bottom surface of each contact is attached to the substrate 16 .

[0046] As shown in Figure 3, as one embodiment of the present invention, base 16 comprises a clamping portion 13 and a transition portion 15. Clamping portion 13 is used to clamp contacts, while transition portion 15 connects the contacts to the clamping portion. Transition portion 15 prevents excessive bending of metal base 16. A micro-plane reflector is provided at the tip of contact 14. Clamping portion 13 of sheet-shaped silver-plated planar multi-contact micro-reflector 9 is fixed in measurement optical path 10 by a fixture, while contact 14 extends into the gap between stacked sheets. Transition portion 15 prevents excessive bending of metal base 16.

[0047] A micro-mirror 17 is provided at the front end of the contact. The micro-mirror 17 is a micro-plane mirror. The sheet-shaped silver-plated plane mirror of the micro-plane mirror is based on a brittle sheet material such as metal or glass, and is coated with a silver film or aluminum film on the surface. A layer of silicon dioxide protective film is attached to the surface of the silver film or aluminum film.

[0048] As shown in Figure 4, as another embodiment of the present invention, substrate 16 is made of a light-transmitting material, such as a glass substrate. The substrate 16 of the micro rectangular prism array multi-contact micro-reflector 9 is fixed by a fixture in the measurement optical path 10, and the micro rectangular prism array extends into the gaps between the stacked sheets. The contacts are micro rectangular prisms, and the hypotenuse of the micro rectangular prism is a micro-reflector 17. Light is incident from the side of substrate 16 and enters the micro-reflector from the right-angled edge of the micro rectangular prism. It is reflected by the micro-reflector and illuminates the surface of the stacked sheet to be measured. The reflected light from the surface of the stacked sheet to be measured illuminates the micro-reflector and then returns along the original path.

[0049] The micro right-angle prism array is made of photoresist silicon oxide material, etc. The micro right-angle prism is a right-angled triangular prism with a right-angle side size of 1um to 10mm, and is manufactured on a glass substrate 16 using a photolithography process or a two-photon polymerization printing technology.

[0050] As shown in FIG5 , as another embodiment of the present invention, substrate 16 is made of a light-transmitting material, such as a glass substrate, and the contact is a micro-channel prism. The micro-channel prism includes two micro-channels, and the connection between the two channels forms a right-angled slope, which is a micro-reflector 17. Micro-channel prism 18 extends vertically into the gap between the stacked sheets. A light beam is incident from the back of substrate 16, is totally reflected by the right-angled slope of micro-channel prism 18, and is reflected back to the stacked sheet to be measured. There, it is reflected again by the right-angled slope of micro-channel prism 18 and reflected back, thereby obtaining surface information of the stacked sheet to be measured.

[0051] A micro-channel prism array with a single size of 1um to 10mm is made of materials such as photoresist, silicon oxide, etc. on a substrate using two-photon polymerization printing technology.

[0052] The measurement object of the present invention is a stacked sheet object, including but not limited to stacked semiconductor wafers, stacked metal sheets, stacked chips, etc.

[0053] As a preference of the present invention, the light source 1 is a parallel light source, or may include multiple light sources and multiple lenses adjusted to parallel light.

[0054] As a preferred embodiment of the present invention, the measuring device further includes an observation camera, which is arranged in the opposite direction of the reference optical path 6. In actual testing, the device also includes a controller and a processing terminal, wherein one end of the controller is connected to the third translation stage 12 and the other end is connected to the processing terminal.

[0055] As a preferred embodiment of the present invention, the measuring device in FIG1 further has a light-shielding housing, which surrounds all devices outside the wafer box to prevent external light from affecting the measurement results.

[0056] Figure 1 also shows a stacking box. When testing stacked wafers, the wafers to be tested are placed in the box. The stacking box is used only to test the measurement performance of the measuring device. In actual use of the measuring device, the object to be measured is a finished, non-detachable stack of wafers such as stacked chips.

[0057] As shown in FIG2 , the measurement principle of the present invention is as follows:

[0058] Schematic diagram of measuring the tilt angle of a reflection point 19 between a single stacked sheet 18 below the multi-contact micro-reflector and a single stacked sheet 18 above the multi-contact micro-reflector. The tilt angle θ is the angle between a tangent 20 on the stacked sheet at the reflection point 19 on the stacked sheet below the multi-contact micro-reflector and the horizontal plane. The figure indicates the parameters required for the tilt angle θ of the reflection point 19: on the camera display screen 21, h is the Y-direction offset of the light beam 23 reflected from the measurement light path in the camera 7 relative to the light beam 22 reflected from the reference light path; h1 is the distance between the reflection point in the multi-contact micro-reflector 9 and the reflection point on the single stacked sheet 18 below the multi-contact micro-reflector (the elevation data of the reflection point); l2 is the sum of the distances between the multi-contact micro-reflector 9, the beam splitter 3, and the camera 7; l2 = l′2 ​​+ l2″.

[0059] Figure 6 is a diagram showing the fitting result of the sheet torsion and bending deformation surface obtained using the data measured by the device in Figure 1. The stacked sheet gap measurement device in Figure 1 is used to measure the elevation data of six points on the edges of two adjacent sheets in the stacked sheet, and the sheet torsion and bending deformation surface is fitted using the two-dimensional Griddata interpolation algorithm.

[0060] Figure 7 is a fitting result diagram of the concave-convex curved deformation surface of the thin sheet obtained by using the data measured by the device in Figure 1. The elevation data and inclination angles of 8 points on the edges of two adjacent thin sheets in the stacked sheet are measured using the stacked sheet gap measurement device in Figure 1, and the concave-convex curved deformation surface of the thin sheet is fitted using a cubic polynomial fitting algorithm.

[0061] In a second aspect of the present invention, a method for measuring a gap between stacked sheets is provided, the method comprising:

[0062] S1: adjusting the first translation stage and the second translation stage respectively so that the distances between the reflector and the multi-contact micro-mirror and the beam splitter are equal. The position of the first translation stage is used as the initial position.

[0063] S2 adjusts the position of the third translation stage so that the multi-contact micro-mirror is placed above the stacked sheets to be measured and the camera generates a plurality of interference patterns of the measured stacked sheets;

[0064] S3 adjusts the position of the first translation stage, obtains multiple interference pattern signals from the camera, and calculates the distance between the multi-contact micro-reflector and the reflection point on the surface of the stacked sheet to be measured, i.e., the elevation value at the reflection point on the surface of the stacked sheet to be measured. Repeat the above steps to find the elevation value of each reflection point on the surface of the stacked sheet to be measured. The elevation value is calculated using existing interference principles and will not be repeated here.

[0065] S4: rotating the third translation stage and recording the rotation angle, and repeating steps S1 to S3 until the elevation values ​​of multiple reflection points on the surface of each stacked sheet to be measured are obtained;

[0066] S5 uses the elevation value of each reflection point and the rotation angle of the third translation stage to fit all the reflection points to obtain a surface curved surface of the stacked sheet to be tested, and determines whether the surface of the stacked sheet to be tested is deformed based on the fitted curved surface.

[0067] In step S3, the elevation is used to calculate the inclination angle of the reflection point. The inclination angle of the reflection point is calculated according to the following relationship:

[0068] Furthermore, during fitting, the fitting method must be determined based on the inclination angle of the reflection point. If the inclination angle is less than the preset threshold, the two-dimensional Griddata interpolation algorithm is used for fitting; otherwise, the cubic polynomial fitting algorithm is used.

[0069] The device provided by the present invention utilizes a multi-contact micro-reflector 9 mounted on a second translation stage. The device uses the multi-contact micro-reflector 9 to reflect a light source 1 on a measurement optical path 10 onto the stacked wafers to be measured, and then reflects the reflected light from the stacked wafers to a spectrometer 3. The optical path is then changed by adjusting a first translation stage 4 in a reference optical path 6, thereby capturing multiple interference patterns containing wafer gap distance information on an observation camera. By adjusting the orientation of the stacked wafers to be measured, edge point data of the gaps between the multiple wafers can be measured, and a fitting algorithm can be used to fit the bending deformation of the wafers.

[0070] The measuring device of the present invention includes a second translation stage, located in the X direction of the measuring optical path 10. This second translation stage does not interfere with the positional relationships of other components in the measuring optical path 10 and is used to adjust the position and direction of the measuring optical path 10. Therefore, the use of the second translation stage, especially during the device commissioning phase, allows for more convenient fine-tuning of the position of the measuring optical path 10, ensuring that the light source 1 exiting the beam splitter 3 is aligned with the multi-contact micro-reflector 9.

[0071] Based on the measurement device of the present invention, the measurement principle of the present invention is that the incoherent light emitted by the light source 1 is converted into several beams of parallel light through a pinhole array mask. The parallel light is then split into two beams by a beam splitter 3. One beam is incident on the reference optical path 6, where the first displacement stage 4 equipped with a reflector 5 reflects the beam; the other beam is incident on the measurement optical path 10, where the multi-contact micro-mirror 9 and stacked plates in the measurement optical path 10 reflect the beam back. The reflected light in the reference optical path 6 and the measurement optical path 10 passes through the beam splitter 3 again and ultimately forms interference fringes that can be observed on the camera. The light source 1 is turned on, and the displacement stage of the measurement optical path 10 is adjusted so that the light source 1 in the measurement optical path 10 is incident on the multi-contact micro-mirror 9. At the same time, the displacement of the first displacement stage 4 of the reference optical path 6 is adjusted to form multiple interference patterns on the camera with the light reflected from the measurement optical path 10. A computer program controls the reference optical path 6, the first translation stage 4, and the observation camera. As the first translation stage 4 slowly and uniformly moves, the interference light intensity from the observation camera is measured at regular intervals. By measuring changes in interference light intensity, the wafer gap is monitored and observed. All components are controlled by the computer. The light intensity data is converted into corresponding displacement data, which is then analyzed and evaluated to determine the wafer gap measurement results.

[0072] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A stacked sheet surface deformation measurement device based on a multi-contact micro-mirror, characterized in that: The measuring device comprises a light source (1), an array mask (2), a beam splitter (3), a reflector (5), a multi-contact micro-reflector (9) and a camera (7), wherein: The beam splitter (3) is arranged behind the light source (1), the array mask (2) is arranged between the beam splitter (3) and the light source (1), the reflector (5) and the multi-contact micro-reflector (9) are both arranged behind the beam splitter (3), and the stacked sheet to be tested (11) is arranged behind the multi-contact micro-reflector (9); The array mask (2) is used to divide the light emitted by the light source into multiple beams of parallel incident light according to the distribution of the mask array, and one beam of light is used to detect the surface deformation of a single stacked sheet; the front end of the multi-contact micro-reflector (9) is provided with multiple micro-reflectors, and during the measurement process, a single micro-reflector extends between adjacent stacked sheets to be measured for detection, and the spacing between the micro-reflectors is set according to the gap between adjacent stacked sheets in the stacked sheets to be measured; Light emitted by a light source (1) passes through the array mask (2) and is divided into several beams of parallel light. For one of the beams of parallel light, the beam of parallel light passes through the beam splitter (3) and is divided into two beams of light with different directions, one beam of light enters the reflector (5) as reference light, and the other beam of light enters a micro-reflector in the multi-contact micro-reflector (9) as measurement light; the measurement light is reflected by the multi-contact micro-reflector (9) and irradiates the surface of the stacked sheet to be measured, and is reflected by the stacked sheet to be measured, and the reflected light returns to the beam splitter (3) along the original path; at the same time, the reference light is reflected by the reflector (5) and enters the beam splitter (3), and the reference light and the measurement light are both reflected by the beam splitter (3) and enter the camera (7) to merge, thereby forming an interference pattern.

2. A stacked sheet surface deformation measuring device based on a multi-contact micro-mirror as claimed in claim 1, characterized in that: The surface of the array mask (2) has pinholes in a linear array, and the distance between the pinhole arrays corresponds to the contact pitch of the multi-contact micro-reflector (9).

3. A stacked sheet surface deformation measuring device based on a multi-contact micro-mirror as claimed in claim 1 or 2, characterized in that: The multi-contact micro-reflector (9) comprises a substrate (16) and a plurality of contacts (14) arranged on the substrate (16); the substrate (16) is made of a light-transmitting material, and the bottom surface of the contacts (14) is in contact with the surface of the substrate (16).

4. The stacked sheet surface deformation measuring device based on a multi-contact micro-mirror as claimed in claim 3, characterized in that: The contact (14) is a micro right-angle prism, the hypotenuse of which is a micro reflector (17), light is incident from the side of the substrate (16), enters the micro reflector (17) from the right-angle edge of the micro right-angle prism, is reflected by the micro reflector (17) and irradiates the surface of the stacked sheet to be tested, and the reflected light after being reflected by the surface of the stacked sheet to be tested irradiates the micro reflector (17), and then returns along the original path.

5. The stacked sheet surface deformation measuring device based on multi-contact micro-mirrors as claimed in claim 3, characterized in that: The contact (14) is a micro-channel prism, which includes two micro-channels, the connection between the two channels is a right-angled slope, and the right-angled slope is a micro-reflector (17). Light is incident from the bottom surface of the substrate (16) into one of the micro-channels, and after being reflected by the micro-reflector (17), it enters the other channel, propagates in the other channel, and reaches the surface of the stacked sheet to be tested. The reflected light after being reflected by the surface of the stacked sheet to be tested is irradiated on the micro-reflector (17), and then returns along the original path.

6. The stacked sheet surface deformation measuring device based on multi-contact micro-mirrors as claimed in claim 3, characterized in that: The base (16) comprises a clamping portion and a transition portion, the clamping portion is used to clamp the contact (14), and the transition portion is used to connect the contact (14) and the clamping portion, and a micro-plane reflector is arranged at the front end of the contact (14), and the micro-plane reflector is a micro-reflector (17).

7. The stacked sheet surface deformation measuring device based on multi-contact micro-mirrors according to claim 6, characterized in that: The micro flat reflector has a brittle sheet material as a base, a silver film or an aluminum film is plated on the surface, a layer of silicon dioxide protective film is attached to the surface of the silver film or the aluminum film, and the size of the contact (14) is 1um to 10mm.

8. A stacked sheet surface deformation measuring device based on a multi-contact micro-mirror as claimed in claim 1 or 2, characterized in that: The stacked sheets (11) to be tested are stacked sheet-like objects, including stacked semiconductor wafers, stacked metal sheets or stacked chips.

9. A stacked sheet surface deformation measuring device based on a multi-contact micro-mirror as claimed in claim 1 or 2, characterized in that: The measuring device further comprises a first displacement stage (4), a second displacement stage (8) and a third displacement stage (12); the first displacement stage (4) is arranged below the reflector (5) and is used to adjust the position of the reflector (5); the second displacement stage (8) is arranged below the multi-contact micro-reflector (9) and is used to adjust the position of the multi-contact micro-reflector (9); the third displacement stage (12) is used to place the stacked sheet to be measured, and the rotation or movement of the third displacement stage drives the stacked sheet to be measured to rotate or move.

10. A method for measuring using the measuring device according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: S1 adjusts the positions of the reflector and the multi-contact micro-reflector so that a plurality of interference patterns are formed in the camera; wherein each contact of the multi-contact micro-reflector is located between adjacent stacked sheets to be tested; S2 calculates the distance between the reflection point of the light in the multi-contact micro-reflector and the reflection point of the light on the surface of the stacked sheet to be tested, that is, the elevation value at the reflection point on the surface of the stacked sheet to be tested; S3: rotating the stacked sheet to be tested and recording the rotation angle, and repeating steps S1 to S2 until the elevation values ​​of multiple reflection points on each surface of the stacked sheet to be tested are obtained; S4 uses the elevation value of each reflection point and the rotation angle to fit all the multiple reflection points to obtain a surface curved surface of the stacked sheet to be tested, and determines whether the surface of the stacked sheet to be tested is deformed according to the fitted curved surface; In step S3, the elevation is also used to calculate the inclination angle of the reflection point; the inclination angle of the reflection point is calculated according to the following relationship: Where h is the deviation in the Y direction of the reflected light from the calculated light path relative to the reflected light from the reference light path in the camera. The distance of rotation, h1 is the distance from the point where the light beam is incident on the multi-contact micro-reflector to the reflection point of the stacked sheet to be measured, and l2 is the sum of the distances between the multi-contact micro-reflector and the beam splitter and the camera; When fitting, the fitting method should be determined according to the inclination angle of the reflection point. If the inclination angle is less than the preset threshold, the two-dimensional Griddata interpolation algorithm is used for fitting; otherwise, the cubic polynomial fitting algorithm is used.

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