Device and method for detecting completely equal optical path confocal imaging of adjacent surfaces of grains based on a Michelson interferometer-like structure

Abstract

The present invention provides a device and method for detecting completely equal-optical-path confocal imaging of adjacent surfaces of a grain based on a Michelson interferometer-like structure. The device comprises a light source, a longitudinally coaxially arranged camera, a telecentric imaging lens, a semi-transparent and semi-reflective parallel-plate image combiner, a glass object turntable, and a semiconductor grain. A parallel-plate compensator and a top-view right-angle turning prism located directly above the semiconductor grain are arranged at the same level as the semi-transparent and semi-reflective parallel-plate image combiner. A side-view right-angle turning prism is arranged at the same level as the semiconductor grain and directly below the semi-transparent and semi-reflective parallel-plate image combiner. The device obtains spatially separated imaging of adjacent surfaces while satisfying the condition of completely equal-optical-path confocal imaging of both surfaces. Compensation errors can be corrected by adjusting the angle between the parallel-plate compensator and the optical axis, thereby achieving simultaneous completely equal-optical-path confocal imaging of both adjacent surfaces of the semiconductor grain. The device has a simple and compact structure, is easy to assemble and debug, and has high reliability.

Description

Technical Field

[0001] The present invention relates to a device and method for detecting completely equal optical path confocal imaging of adjacent surfaces of grains based on a Michelson interferometer-like structure. Background Art

[0002] One of the key technical challenges in achieving simultaneous double-sided defect detection is achieving complete equal-path confocal imaging of the optical path for double-sided imaging inspection of semiconductor cooling device die. Currently, research on simultaneous defect imaging inspection of adjacent double-sided semiconductor die based on various inspection devices and methods has resulted in related patent applications:

[0003] like Figure 1 As shown: Invention Patent Application No. 202010171706.0X, Patent Application Name: New Apparatus and Method for Simultaneous Quasi-Equal-Pathlength Confocal Imaging Detection of Adjacent Surfaces of Semiconductor Dies. The proposed optical detection apparatus and method effectively solve the problem of "quasi" confocal imaging detection of adjacent surfaces of semiconductor grains. However, there is still an optical path difference between the adjacent double-sided imaging light paths. In order to obtain simultaneous confocal imaging of adjacent surfaces, it is necessary to compensate for this small optical path difference by selecting a telecentric imaging lens with a sufficiently large depth of field. Therefore, it is necessary to find a new way to detect confocal imaging of adjacent surfaces of grains with completely equal-pathlength.

[0004] like Figure 2 As shown: The invention patent application number is 202010191734.8, and the patent application name is: A new method for simultaneous equal-optical-path confocal imaging detection of double-sided grains based on time difference resolution. A new method for simultaneous equal-optical-path confocal imaging detection of adjacent surfaces of semiconductor grains based on time difference resolution imaging is proposed using a single-group imaging system.

[0005] like Figure 3 As shown: Patent application name: Device and method for simultaneous equal-optical-path confocal imaging detection of both sides of grains based on two-color separation imaging method. The invention patent application number is 202010203153.1. A new method for simultaneous and completely equal-optical-path confocal imaging detection of adjacent surfaces of semiconductor grains based on two-color separation imaging method is proposed.

[0006] like Figure 4 As shown: The invention patent application number is 202010250856.X, and the patent application title is "Device and method for simultaneous complete equal-path confocal imaging of both sides of a grain based on polarization separation imaging." A polarization beam splitter is used to obtain two illumination beams with mutually perpendicular polarization directions, which are used to illuminate the adjacent two sides of the semiconductor grain to be tested. A method based on polarization separation imaging (abbreviated as "polarization separation") is further proposed, which uses a polarization camera to achieve simultaneous complete equal-path confocal imaging of adjacent surfaces of semiconductor grains.

[0007] like Figure 5As shown: The invention patent application number is 202010296134.8, and the patent name is a device and method for realizing simultaneous equal-optical-path confocal detection of both sides of grains using polarization image separation. It proposes a new method that is still based on the principle of polarized light separation imaging (referred to as "polarization image separation"), combined with a "polarization image separation prism assembly" and uses an ordinary CMOS or CCD camera to realize simultaneous and completely equal-optical-path confocal imaging detection of adjacent surfaces of semiconductor grains.

[0008] The above-mentioned various detection devices usually require the use of polarization optical elements or polarization CMOS sensors, which are slightly complex in structure or use, relatively expensive, and have insufficient error compensation capabilities for simultaneously achieving equal optical path and double-sided separation imaging detection. Summary of the Invention

[0009] The present invention improves the above-mentioned problem. That is, the technical problem to be solved by the present invention is that the currently designed complete equal optical path confocal imaging detection has a high cost and insufficient error compensation capability.

[0010] The specific embodiment of the present invention is: a completely equal optical path confocal imaging detection device for adjacent surfaces of a crystal grain based on a Michelson interferometer-like structure, comprising a CMOS or CCD camera, a telecentric imaging lens, a semi-transparent and semi-reflective parallel plate image combiner, and a glass object turntable, which are sequentially arranged in the direction of the optical path, and a semiconductor crystal grain placed on the glass object turntable, wherein a top right-angle image rotation prism, a parallel plate compensator, and a side right-angle turning prism are sequentially arranged in the optical path between the semiconductor crystal grain and the semi-transparent and semi-reflective parallel plate image combiner, and the side right-angle image rotation prism and the top right-angle turning prism are sequentially arranged. The image prisms are respectively located on the front side of the semiconductor die and directly above the celestial plane. The celestial plane right-angle turning prism is located at the same horizontal height as the parallel plate compensator and the semi-transparent and semi-reflective parallel plate image combiner. The side right-angle turning prism and the semi-transparent and semi-reflective parallel plate image combiner are located on the optical axis of the telecentric imaging lens. At the same time, the first right-angle surface of the side right-angle turning prism is opposite to the first surface of the semi-transparent and semi-reflective parallel plate image combiner, and the second right-angle surface of the side right-angle turning prism is opposite to the side surface of the semiconductor die. The oblique surface of the side right-angle turning prism is arranged at an inclination relative to the optical axis of the telecentric imaging lens.

[0011] The two right-angled surfaces of the zenithal right-angle image-reversing prism are respectively opposite to the zenithal surface of the semiconductor die and the second surface of the semi-transparent and semi-reflective parallel-plate image combiner; a coaxial external illumination light source is provided on the side of the semi-transparent and semi-reflective parallel-plate image combiner facing away from the second surface;

[0012] The light source is separated into a first horizontal light path and a second vertical light path by a semi-transmissive and semi-reflective parallel plate image combiner. The first light path passes through a first right-angle image rotation prism to illuminate the top surface of the semiconductor crystal grain located on the glass object turntable; the second light path passes through a second right-angle image rotation prism to illuminate the side surface of the semiconductor crystal grain to be measured.

[0013] The imaging beam from the semiconductor crystal surface is incident on the parallel plate compensator through the first right-angle image rotation prism, and then is parallelly emitted by the parallel plate compensator, resulting in a displacement of s, and then reflected by the semi-transparent and semi-reflective parallel plate combiner to reach the reference output surface;

[0014] The imaging light beam from the side of the semiconductor crystal grain is reflected and redirected by the second right-angle image-reversing prism, and then transmitted through the semi-transparent and semi-reflective parallel plate image combiner to reach the reference output surface; the camera obtains independent images of both sides.

[0015] Furthermore, the right-angle side length d of the top right-angle turning prism and the side right-angle turning prism is the same, the semiconductor grain is located at the center of the glass object turntable, the center of the semi-transparent and semi-reflective parallel plate combiner, the center of the reflective surface of the top right-angle turning prism and the side right-angle turning prism, and the center of the semiconductor grain are connected to form a square symmetrical optical path structure with a side length of D / 2+d, where D is the width of the transparent glass object stage and the center of the glass object turntable.

[0016] Furthermore, the distance between the center of the semi-transparent and semi-reflective parallel-plate image combiner and the center of the oblique surface of the side right-angle turning prism is D / 2+d, and the working distance of the imaging light path on the side of the semiconductor crystal grain is WD=D / 2+d / 2. The semi-transparent and semi-reflective parallel-plate image combiner and the oblique surface of the right-angle turning prism on the sky are at the same horizontal height, and the distance between the two is D / 2+d. The working distance of the imaging light path on the sky surface of the semiconductor crystal grain is WD=D / 2+d / 2.

[0017] Furthermore, the size of the top right-angle image-transmitting prism is 15*15*15mm, and the size of the side right-angle image-transmitting prism is 15*15*15mm.

[0018] Furthermore, the parallel plate compensator causes the semiconductor crystal grain sky imaging light beam to produce a parallel displacement s, the size of which depends on the thickness t of the parallel plate compensator. The thickness of the semi-transparent and semi-reflective parallel plate combiner is the glass refractive index n1 and the angle θ1 between the surface normal of the parallel plate compensator and the optical axis. The material of the parallel plate compensator is K9 glass.

[0019] Furthermore, the parallel plate compensator produces a double image separation of s = 1.5 mm, a focal length of f = 51.5 mm, and a WD = 110 mm.

[0020] Furthermore, the thickness of the parallel plate compensator is 6.5 mm, the angle between its normal and the optical axis is 12°, and the material of the parallel plate compensator is K9 glass.

[0021] Furthermore, the coaxial external illumination light source is monochromatic light, or a quasi-monochromatic light source with a certain spectral bandwidth or white light.

[0022] The present invention also includes a method for detecting confocal imaging of adjacent surfaces of a crystal grain with completely equal optical path lengths based on a Michelson interferometer-like structure, comprising a CMOS or CCD camera, a telecentric imaging lens, a semi-transparent and semi-reflective parallel plate image combiner, and a glass object turntable, which are sequentially arranged in the direction of the optical path; a top right-angle image rotation prism, a parallel plate compensator, and a side right-angle image rotation prism are sequentially arranged in the optical path between the semiconductor crystal grain and the semi-transparent and semi-reflective parallel plate image combiner; and a side right-angle image rotation prism and a top right-angle image rotation prism. They are respectively located on the front side of the semiconductor die and directly above the zenith. The zenith right-angle turning prism is located at the same horizontal height as the parallel plate compensator and the transflective parallel plate image combiner. The side right-angle turning prism and the transflective parallel plate image combiner are located on the optical axis of the telecentric imaging lens. At the same time, the first right-angle surface of the side right-angle turning prism is opposite to the first surface of the transflective parallel plate image combiner, and the second right-angle surface of the side right-angle turning prism is opposite to the side surface of the semiconductor die. The oblique surface of the side right-angle turning prism is arranged obliquely with respect to the optical axis of the telecentric imaging lens.

[0023] The two right-angled surfaces of the zenithal right-angle image-reversing prism are respectively opposite to the zenithal surface of the semiconductor die and the second surface of the semi-transparent and semi-reflective parallel-plate image combiner; a coaxial external illumination light source is provided on the side of the semi-transparent and semi-reflective parallel-plate image combiner facing away from the second surface;

[0024] When working, double-sided lighting light path:

[0025] The light source is separated into a first horizontal light path and a second vertical light path by a semi-transmissive and semi-reflective parallel plate image combiner. The first light path passes through a first right-angle image rotation prism to illuminate the top surface of the semiconductor crystal grain located on the glass object turntable; the second light path passes through a second right-angle image rotation prism to illuminate the side surface of the semiconductor crystal grain to be measured.

[0026] Imaging detection optical path: The imaging beam from the semiconductor crystal surface is incident on the parallel plate compensator through the first right-angle image rotation prism, and then is parallelly emitted by the parallel plate compensator, resulting in a displacement of s, and then reflected by the semi-transparent and semi-reflective parallel plate combiner to reach the reference output surface;

[0027] The imaging light beam from the side of the semiconductor crystal grain is reflected and redirected by the second right-angle image-reversing prism, and then transmitted through a semi-transparent and semi-reflective parallel plate image combiner to reach the reference output surface; the camera obtains independent images of both sides.

[0028] Compared with existing technologies, the present invention has the following advantages: This patent application proposes a new device and method for confocal imaging of adjacent surfaces with perfect equal optical path lengths based on a Michelson interferometer-like structure. This device uses two parallel glass plates in the optical path for imaging the adjacent surfaces to achieve spatial separation. This new device can simultaneously achieve perfect equal optical path length confocal imaging of two adjacent surfaces of a semiconductor die without the need for polarization optical elements or a polarization CMOS sensor (camera), effectively reducing the cost of the detection device.

[0029] 1) This device is a double-parallel-plate structure based on a Michelson interferometer-like structure, which can achieve simultaneous and completely equal-path confocal imaging detection of adjacent two sides of semiconductor grains. It has a simple structure and is easy to install and adjust.

[0030] 2) In the imaging optical path of this device, the double image separation distance s can be increased or decreased by adjusting the angle between the parallel plate compensator and the optical axis, with little effect on the optical path difference; the resulting small optical path difference can be compensated by the depth of field of the telecentric imaging lens.

[0031] 3) The imaging optical path of this device can be compensated by replacing parallel plate compensators of different thicknesses to change the angle between the parallel plate compensator 7 and the optical axis and the original slight optical path difference of the mechanism, thereby achieving simultaneous and completely equal optical path confocal imaging detection of adjacent double sides of semiconductor grains.

[0032] 4) This device can also correct and compensate for slight optical path differences caused by angular manufacturing errors and assembly errors of the semi-transparent and semi-reflective parallel plate image combiner or the right-angle image-reversing prism by adjusting the angle between the parallel plate compensator and the optical axis.

[0033] 5) This device utilizes a conventional parallel-plate compensator, parallel-plate image combiner, and CMOS or CCD camera, eliminating the need for polarization optical components and a polarization CMOS sensor (camera). Furthermore, it offers enhanced double-sided image separation and manufacturing error compensation capabilities. This device can effectively reduce the cost of inspection equipment and improve its cost-effectiveness.

[0034] 6) The device for simultaneously imaging and detecting adjacent double sides of semiconductor grains has a simple and compact structure, is easy to assemble and debug, and has good reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1-5 It is an existing optical device for detecting adjacent surfaces of semiconductor grains;

[0036] In the above figures, 1 is a black and white camera, 2 is a telecentric imaging lens, 3 is a cubic beam splitter, 4 is a semiconductor die, 5 is a transparent glass stage, 6 or 6a or 6b is an image transfer prism, 7 or 7a or 7b is a light source, 8 and 9 are filters; 8a is a polarizing prism; 8b is a roof prism; and 8c is a trigger signal controller.

[0037] Figure 6 This is the detection device of this patent application.

[0038] Figure 7 This is a schematic diagram of the rotation of the parallel plate compensator of this patent.

[0039] Figure 8 This is a design embodiment of this patent application. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] like Figures 6-8 As shown, a completely equal-path confocal imaging detection device for adjacent surfaces of a grain based on a Michelson interferometer-like structure includes a CMOS or CCD camera 1, a telecentric imaging lens 2, a semi-transparent and semi-reflective parallel plate image combiner 3, a glass object turntable 5, and a semiconductor grain 6 placed on the glass object turntable. A top right-angle image rotation prism 4a, a parallel plate compensator 7, and a side right-angle image rotation prism 4b are respectively arranged in sequence on the optical path between the semiconductor grain 6 and the semi-transparent and semi-reflective parallel plate image combiner. The side right-angle image rotation prism and the top right-angle image rotation prism are respectively located at The front side of the semiconductor die and directly above the celestial plane are located at the same level as the parallel plate compensator 7 and the transflective parallel plate image combiner. The side right-angle image turning prism and the transflective parallel plate image combiner are located on the optical axis of the telecentric imaging lens 2. The first right-angle surface 401b of the side right-angle image turning prism faces the first surface 301 of the transflective parallel plate image combiner, the second right-angle surface 402b of the side right-angle image turning prism faces the side surface of the semiconductor die, and the inclined surface 403b of the side right-angle image turning prism is inclined relative to the optical axis of the telecentric imaging lens.

[0042] The two right-angled surfaces of the zenithal right-angle image-reversing prism are respectively opposite to the zenithal surface of the semiconductor die and the second surface 302 of the semi-transparent and semi-reflective parallel-plate image combiner; a coaxial external illumination light source 8 is provided on the side of the semi-transparent and semi-reflective parallel-plate image combiner facing away from the second surface 302, i.e., on the side of the first surface 301;

[0043] The illumination light source 8 is separated into a first horizontal optical path and a second longitudinal optical path after passing through the semi-transmissive and semi-reflective parallel plate image combiner 3. The first optical path passes through the parallel plate compensator 7 and the first right-angle image-reversing prism to illuminate the top surface of the semiconductor crystal grain 6 located on the glass sample turntable. The second optical path passes through the second right-angle image-reversing prism to illuminate the side surfaces of the semiconductor crystal grain 6 to be measured. The two illumination beams respectively illuminate two adjacent surfaces of the semiconductor crystal grain 6, providing sufficient illumination conditions for simultaneous imaging of both sides of the crystal grain.

[0044] Imaging detection optical path:

[0045] The two adjacent faces of the semiconductor crystal grain 6 illuminated by the light source generate diffuse light. The imaging beam from the top face of the semiconductor crystal grain passes through the top face right-angle image-reversing prism 4a and is incident on a parallel plate compensator 7 with a thickness of . The beam then exits parallelly through the parallel plate compensator 7, undergoing a displacement of s. The beam is then reflected by the semi-transparent and semi-reflective parallel plate image combiner 3 and arrives at the reference output face. The imaging beam from the side face of the semiconductor crystal grain is reflected and deflected by the side right-angle image-reversing prism 4b and then transmitted through the semi-transparent and semi-reflective parallel plate image combiner 3 to arrive at the reference output face. A CMOS or CCD camera can then obtain independent images of both faces.

[0046] The illumination light source 8 with a parallel light beam incident on the right side of the semi-transparent and semi-reflective parallel plate image combiner 3, or the illumination light source 8 set in front of the right-angle image-turning prisms 4a and 4b on the top and side surfaces can be monochromatic light, or a quasi-monochromatic light source with a certain spectral bandwidth, or white light.

[0047] The right-angle side length d of the top right-angle turning prism and the side right-angle turning prism is the same; the glass stage turntable is circular; the semiconductor grain is located at the center of the glass stage turntable; the center of the semi-transparent and semi-reflective parallel plate combiner, the center of the reflective surface of the top right-angle turning prism and the side right-angle turning prism, and the center of the semiconductor grain are connected to form a square symmetrical optical path structure with a side length of D / 2+d, where D is the width of the transparent glass stage and the center of the glass stage turntable.

[0048] The distance between the center of the semi-transparent and semi-reflective parallel-plate image combiner and the center of the oblique surface of the side right-angle turning prism is D / 2+d. The working distance of the imaging optical path on the side of the semiconductor crystal grain is WD=D / 2+d / 2. The semi-transparent and semi-reflective parallel-plate image combiner and the oblique surface of the right-angle turning prism on the sky are at the same horizontal height. The distance between the two is D / 2+d. The working distance of the imaging optical path on the sky surface of the semiconductor crystal grain is WD=D / 2+d / 2.

[0049] The parallel plate compensator 7 causes the imaging light beam of the semiconductor crystal grain 6 to produce a parallel displacement s, the size of which depends on the thickness t of the parallel plate compensator 7, the thickness of the semi-transparent and semi-reflective parallel plate combiner 3, the glass refractive index n1, and the angle θ1 between the surface normal of the parallel plate compensator 7 and the optical axis.

[0050] Use ordinary CMOS or CCD cameras to obtain complete iso-optical confocal imaging detection of the top and side surfaces of semiconductor grains.

[0051] In this embodiment, Figure 7 , 8 shows a design embodiment of the front prism image transfer subsystem of the semiconductor grain adjacent surface confocal imaging detection device with complete equal optical path length proposed by the patent of the present invention.

[0052] 1) In this embodiment, the length, width and thickness of the right-angle image rotation prism for the top detection light path of the semiconductor die are 15*15*15mm, the length, width and thickness of the right-angle image rotation prism for the side detection light path of the semiconductor die are 15*15*15mm, and the width of the transparent glass stage is 45mm.

[0053] 2) The center of the semi-transmissive and semi-reflective parallel plate combiner 3, the centers of the reflective surfaces of the right-angle image-reversing prisms 4a and 4b, and the centers of the semiconductor crystal grains are connected to form a square symmetrical optical path structure with a side length of D / 2+d=37.5mm.

[0054] 3) The transflective parallel plate image combiner 3 has a side length of 15 mm and a thickness of 6 mm, and is parallel to the hypotenuse of the zenithal right-angle image-reversing prism and the side right-angle image-reversing prism.

[0055] 4) The working distance of the optical path for side imaging of semiconductor crystal grains is WD = D / 2 + d / 2 = 30 mm, and the working distance of the optical path for top imaging of semiconductor crystal grains is WD = D / 2 + d / 2 = 30 mm.

[0056] like Figure 7 As shown, the thickness of the parallel plate compensator 7 is h, and the angle between its normal and the optical axis of the incident light is θ, and the angle between its normal and the optical axis of the outgoing light is θ'; θ1 is the angle between the normal of the parallel plate compensator and the normal of the semi-transparent semi-antiparallel plate combiner and the optical axis of the incident light. When the angle is 45°, it is the initial state of the Michelson interferometer structure. θ1' is the angle between the normal of the parallel plate compensator and the normal of the semi-transparent semi-antiparallel plate combiner and the optical axis of the outgoing light. θ2 is the angle between the normal of the parallel plate compensator after rotation in the device and the optical axis of the incident light. It is a state in which the Michelson interferometer structure is slightly changed. θ2' is the angle between the normal of the parallel plate compensator after rotation in the device and the optical axis of the outgoing light.

[0057] When the angle between parallel plate compensator 7 and the optical axis is 45°, the absolute values ​​of the image separation distance and the optical path difference are both 0. The further the deflection angle deviates from 45°, the greater the absolute values ​​of the image separation distance and the optical path difference. To achieve an image separation distance greater than 1.5 mm, the incident angle should be approximately <14° or >64°. Observation shows that when the parallel plate compensator 7 is deflected to an angle less than 45°, the absolute value of the optical path difference changes more slowly than when it is deflected to an angle greater than 45°. Therefore, a deflection angle of <14° is more reasonable, resulting in an optical path difference of -0.65 mm. This system achieves both double-sided image separation and minimizes the optical path difference, making it suitable for optical devices that require simultaneous double-sided inspection and imaging.

[0058] Relationship between parallel plate compensator thickness and optical path difference:

[0059] Taking the incident angle of the parallel plate compensator 7 as 45° as the design basis, ensuring the device's mechanical position is equal to the optical path (point O and point O' coincide), change the thickness t of the parallel plate compensator 7 to t':

[0060] If only the thickness of the parallel plate compensator 7 is changed while the incident angle remains unchanged, and the output angle is only related to the incident angle and the refractive index

[0061] θ1=θ2=45°, θ1'=θ2', n1*sinθ1'=n*sinθ1 (n=1)

[0062] At this time, the distance s between the centers of the two clear images is:

[0063] s = t4-t2 = t'*sin(θ2-θ2') / cosθ2' - t*sin(θ1-θ1') / cosθ1'

[0064] =(t'-t)*sin(θ1-θ1') / cosθ1'

[0065] The optical path difference can be expressed as:

[0066] The original parallel plate compensator thickness t optical path optical length: Δ1=IJ*n1+JP+PO

[0067] The thickness of the parallel plate compensator t' is the optical path: Δ2=IJ'*n1+J'O'+O'P

[0068] Δ1-Δ2=IJ*n1+JP+PO -(IJ'*n1+J'O'+O'P)

[0069] Among them, x1=IJ, x2=IJ', J'O'=t3-t1+JP, O'P=OP=t4-t2

[0070] =x1*n1+(t4-t2)-x2*n1-(t3-t1)- (t4-t2)

[0071] =x1*n1 – x2*n1-(t3-t1)

[0072] =t*n1 / cosθ1'–(t'-t)*cos(θ1-θ1') / cosθ1'

[0073] The parameters t1, t2, t3, and t4 are as follows: Figure 7 As shown, it can be calculated based on the geometric relationship.

[0074] As can be seen above, when the thickness of parallel plate compensator 7 is changed, the image separation distance and the optical path difference change in a negative relationship. When the thickness of parallel plate compensator 7 is increased, the image on the celestial surface separates more to the left, and the optical path difference increases linearly in the negative direction. When the thickness of parallel plate compensator 7 is decreased, the image on the celestial surface separates more to the right, and the optical path difference increases linearly in the positive direction.

[0075] In summary, the conclusion of increasing the separation distance by changing the incident angle of the parallel plate compensator 7 is that when the deflection angle of the parallel plate compensator 7 is deflected in a direction less than 45°, the thickness of the parallel plate compensator 7 can be reduced, and when the deflection angle is deflected in a direction greater than 45°, the thickness of the parallel plate compensator 7 can be increased, so as to achieve the purpose of reducing the optical path difference and increasing the imaging separation distance.

[0076] In order to make the double image separation distance sufficiently large and the optical path difference as small as possible, this embodiment provides the following three parallel plate compensator placement solutions that meet the conditions:

[0077] a) The thickness of the parallel plate compensator 7 is 6 mm, and the angle between its normal and the optical axis is 14°. The parallel plate compensator is made of K9 glass. The double image of this solution has an optical path difference of 0.65 mm.

[0078] b) The thickness of the parallel plate compensator 7 is 6.2 mm, and the angle between its normal and the optical axis is 19°. The parallel plate compensator is made of K9 glass, and the turning prism of the antenna mechanism needs to be adjusted downward by 0.26 mm. The optical path difference of the double image in this solution is zero.

[0079] c) The parallel plate compensator 7 is 6.5 mm thick, and the angle between its normal and the optical axis is 12°. The parallel plate compensator is made of K9 glass. The optical path difference of the double image in this solution is zero.

[0080] 5) The angular displacement error of the double image caused by the angular tolerance (≤30 arc seconds) of the transflective parallel plate image combiner 3, the parallel plate compensator 7 and the right-angle image rotation prism should be controlled within 2 arc minutes.

[0081] Unless otherwise stated, for any of the technical solutions disclosed in the present invention, if a numerical range is disclosed, the disclosed numerical range is a preferred numerical range. Any person skilled in the art should understand that the preferred numerical range is merely a numerical range that is representative or has a more obvious technical effect among many feasible numerical values. Due to the large number of numerical values, it is impossible to enumerate them exhaustively. Therefore, the present invention discloses some numerical values ​​to illustrate the technical solutions of the present invention. Moreover, the numerical values ​​listed above should not be construed as limiting the scope of protection of the present invention.

[0082] If words such as "first" and "second" are used in this document to limit components, those skilled in the art should know that the use of "first" and "second" is only for the convenience of description to distinguish between components. Unless otherwise stated, the above words have no special meaning.

[0083] In addition, unless otherwise stated, the terms used in any technical solution disclosed in the present invention to express positional relationships or shapes include states or shapes that are approximate, similar, or close thereto.

[0084] Any component provided by the present invention may be assembled from multiple separate components, or may be a separate component manufactured by an integral molding process.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention. They should all be included in the scope of the technical solution for protection of the present invention.

Claims

1. A confocal imaging detection device for completely equal optical path lengths of adjacent grain surfaces based on a Michelson interferometer-like structure, characterized in that: The invention comprises a CMOS or CCD camera, a telecentric imaging lens, a transflective parallel-plate image combiner, a glass object turntable, and a semiconductor die placed on the glass object turntable. A sky plane right-angle image rotation prism, a parallel-plate compensator, and a side right-angle turning prism are sequentially arranged in the optical path between the semiconductor die and the transflective parallel-plate image combiner. The side right-angle image rotation prism and the sky plane right-angle image rotation prism are respectively located on the front side of the semiconductor die and directly above the sky plane. The sky plane right-angle turning prism, the parallel-plate compensator, and the transflective parallel-plate image combiner are located at the same horizontal height. The side right-angle image rotation prism and the transflective parallel-plate image combiner are located on the optical axis of the telecentric imaging lens. A first right-angle surface of the side right-angle image rotation prism is opposite to a first surface of the transflective parallel-plate image combiner, a second right-angle surface of the side right-angle image rotation prism is opposite to a side surface of the semiconductor die, and an inclined surface of the side right-angle image rotation prism is inclined relative to the optical axis of the telecentric imaging lens. The two right-angled surfaces of the zenithal right-angle image-reversing prism are respectively opposite to the zenithal surface of the semiconductor die and the second surface of the semi-transparent and semi-reflective parallel-plate image combiner; a coaxial external illumination light source is provided on the side of the semi-transparent and semi-reflective parallel-plate image combiner facing away from the second surface; The light source is separated into a first horizontal light path and a second vertical light path by a semi-transmissive and semi-reflective parallel plate image combiner. The first light path passes through a first right-angle image rotation prism to illuminate the top surface of the semiconductor crystal grain located on the glass object turntable; the second light path passes through a second right-angle image rotation prism to illuminate the side surface of the semiconductor crystal grain to be measured. The imaging beam from the semiconductor crystal surface is incident on the parallel plate compensator through the first right-angle image rotation prism, and then is parallelly emitted by the parallel plate compensator, resulting in a displacement of s, and then reflected by the semi-transparent and semi-reflective parallel plate combiner to reach the reference output surface; The imaging beam from the side of the semiconductor die is reflected and redirected by a second right-angle image-reversing prism, then transmitted through a semi-transparent and semi-reflective parallel-plate image combiner to reach the reference output surface; the camera obtains independent images of both sides. The right-angle turning prism on the top and the right-angle turning prism on the side have the same length d as the prism right angle, the semiconductor grain is located at the center of the glass turntable, the center of the semi-transparent and semi-reflective parallel plate combiner, the center of the reflective surface of the top right-angle turning prism and the side right-angle turning prism and the center of the semiconductor grain are connected to form a square symmetrical optical path structure with a side length of D / 2+d, where D is the width of the glass turntable; The distance between the center of the semi-transparent and semi-reflective parallel-plate image combiner and the center of the oblique surface of the side right-angle turning prism is D / 2+d. The working distance of the imaging optical path on the side of the semiconductor die is WD=D / 2+d / 2. The semi-transparent and semi-reflective parallel-plate image combiner and the oblique surface of the right-angle turning prism on the sky are at the same horizontal height. The distance between the two is D / 2+d. The working distance of the imaging optical path on the sky of the semiconductor die is WD=D / 2+d / 2. The size of the top right-angle image-changing prism is 15*15*15mm, and the size of the side right-angle image-changing prism is 15*15*15mm; The parallel plate compensator causes the semiconductor crystal grain imaging beam to produce a parallel displacement s. The magnitude of s depends on the thickness h of the glass parallel plate compensator. The thickness of the semi-transmissive and semi-reflective parallel plate image combiner is the glass refractive index n1 and the angle θ1 between the surface normal of the glass parallel plate compensator and the optical axis. The parallel plate compensator is made of K9 glass. The double image separation produced by the parallel plate compensator is s = 1.5 mm, the focal length is f = 51.5 mm, and the WD = 110 mm.

2. The device for detecting completely equal optical path length confocal imaging of adjacent surfaces of grains based on a Michelson interferometer-like structure according to claim 1, characterized in that: The thickness of the parallel plate compensator is 6.5 mm, the angle between its normal and the optical axis is 12°, and the material of the parallel plate compensator is K9 glass.

3. The device for detecting completely equal optical path length confocal imaging of adjacent surfaces of grains based on a Michelson interferometer-like structure according to claim 1, characterized in that: The coaxial external illumination light source is monochromatic light, or a quasi-monochromatic light source with a certain spectral bandwidth or white light.

4. A method for detecting confocal imaging of adjacent surfaces of grains based on a Michelson interferometer-like structure, characterized by: The device is based on a Michelson interferometer-like structure and is characterized in that it includes a CMOS or CCD camera, a telecentric imaging lens, a semi-transparent and semi-reflective parallel plate image combiner, and a glass object turntable, which are sequentially arranged in the direction of the optical path, and a semiconductor crystal placed on the glass object turntable. A top right-angle image rotation prism, a parallel plate compensator, and a side right-angle image rotation prism are sequentially arranged in the optical path between the semiconductor crystal and the semi-transparent and semi-reflective parallel plate image combiner. They are respectively located on the front side of the semiconductor die and directly above the zenith. The zenith right-angle turning prism is located at the same horizontal height as the parallel plate compensator and the transflective parallel plate image combiner. The side right-angle turning prism and the transflective parallel plate image combiner are located on the optical axis of the telecentric imaging lens. At the same time, the first right-angle surface of the side right-angle turning prism is opposite to the first surface of the transflective parallel plate image combiner, and the second right-angle surface of the side right-angle turning prism is opposite to the side surface of the semiconductor die. The oblique surface of the side right-angle turning prism is arranged obliquely with respect to the optical axis of the telecentric imaging lens. The two right-angled surfaces of the zenithal right-angle image-reversing prism are respectively opposite to the zenithal surface of the semiconductor die and the second surface of the semi-transparent and semi-reflective parallel-plate image combiner; a coaxial external illumination light source is provided on the side of the semi-transparent and semi-reflective parallel-plate image combiner facing away from the second surface; The right-angle turning prism on the top and the right-angle turning prism on the side have the same length d as the prism right angle, the semiconductor grain is located at the center of the glass turntable, the center of the semi-transparent and semi-reflective parallel plate combiner, the center of the reflective surface of the top right-angle turning prism and the side right-angle turning prism and the center of the semiconductor grain are connected to form a square symmetrical optical path structure with a side length of D / 2+d, where D is the width of the glass turntable; The distance between the center of the semi-transparent and semi-reflective parallel-plate image combiner and the center of the oblique surface of the side right-angle turning prism is D / 2+d. The working distance of the imaging optical path on the side of the semiconductor die is WD=D / 2+d / 2. The semi-transparent and semi-reflective parallel-plate image combiner and the oblique surface of the right-angle turning prism on the sky are at the same horizontal height. The distance between the two is D / 2+d. The working distance of the imaging optical path on the sky of the semiconductor die is WD=D / 2+d / 2. When working, double-sided lighting light path: The light source is separated into a first horizontal light path and a second vertical light path by a semi-transmissive and semi-reflective parallel plate image combiner. The first light path passes through a first right-angle image rotation prism to illuminate the top surface of the semiconductor crystal grain located on the glass object turntable; the second light path passes through a second right-angle image rotation prism to illuminate the side surface of the semiconductor crystal grain to be measured. Imaging detection optical path: The imaging beam from the semiconductor crystal surface is incident on the parallel plate compensator through the first right-angle image rotation prism, and then is parallelly emitted by the parallel plate compensator, resulting in a displacement of s, and then reflected by the semi-transparent and semi-reflective parallel plate combiner to reach the reference output surface; The imaging light beam from the side of the semiconductor crystal grain is reflected and redirected by the second right-angle image-reversing prism, and then transmitted through a semi-transparent and semi-reflective parallel plate image combiner to reach the reference output surface; the camera obtains independent images of both sides.

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