Device and Method for Detecting Double-Sided Simultaneous Complete Equal Optical Path Confocal Imaging of Grains Based on Polarization Separation Imaging Method

Abstract

The present invention discloses a device and method for semiconductor grain double-sided simultaneous fully equal optical path confocal imaging detection based on polarization separation imaging method. The device includes a CMOS or CCD polarization camera, a telecentric imaging lens, a polarization cube beam splitter, a right-angle image rotation prism, a semiconductor grain, and a transparent glass stage for placing the semiconductor grain, which are sequentially arranged in the optical path direction. The advantages of the device and method of the present invention are as follows: It can achieve double-sided simultaneous fully equal optical path confocal polarization imaging detection of the object to be measured, that is, △ = 0, without the need to use a large-depth-of-field telecentric lens to compensate for the optical path difference of double-sided imaging; the double-sided simultaneous polarization imaging detection device has a simple and compact structure and is easy to assemble and debug.

Description

Technical Field:

[0002] The present invention belongs to the fields of optical detection and machine vision, and particularly relates to a device and method for simultaneously and completely isoptical-path confocal imaging detection of both sides of a semiconductor die based on polarization separation imaging method. Background Art:

[0004] The main optical technical problems to be solved by the device and method for simultaneous defect detection of opposite or adjacent faces of a semiconductor die include isoptical-path confocal imaging of the double-sided detection optical path. Existing authorized patents and patent applications all use large-depth-of-field telecentric imaging lenses to solve the confocal and resolution problems caused by the optical path difference between the double-sided imaging optical paths. The patent applications (application numbers 2019113692573, 2020101330447, not published) have solved the device and method for simultaneous isoptical-path confocal imaging and equal-illuminance illumination of opposite faces of the die, as Figure 1 shown in FIG. 2.

[0005] However, Figure 3 the optical detection device and method proposed in application number 202010171706X (not published) have well solved the quasi-isoptical-path confocal imaging detection of adjacent faces of a semiconductor die, but there is still an optical path difference △ between the adjacent double-sided imaging optical paths. This small optical path difference △ can be compensated by selecting a telecentric imaging lens with a sufficiently large depth of field. When the size of the semiconductor die to be detected increases, the optical path difference △ and the object space field of view VOF = △ + a also increase. A telecentric imaging lens with a large field of view and a large depth of field must be used, which will correspondingly increase the cost of the telecentric imaging lens.

[0006] Figure 4 A new method for realizing complete isoptical-path confocal imaging detection of adjacent faces of a semiconductor die using a single imaging system based on time-difference resolution imaging method is proposed.

[0007] However, in the above-mentioned semiconductor die double-sided detection devices or methods, a coaxial built-in illumination source or a coaxial external illumination source is usually used, and the use of a semi-transmissive and semi-reflective beam splitter will cause an energy loss of 50% of the illumination light. Summary of the Invention:

[0009] Aiming at the problems existing in the above-mentioned adjacent face detection, the present invention application proposes a device and method for simultaneously and completely isoptical-path confocal imaging detection of both sides of a semiconductor die based on polarization separation imaging method. This device and method are beneficial to realizing simultaneous and complete isoptical-path confocal imaging detection of adjacent double sides of a semiconductor die, and do not require the use of a large-depth-of-field telecentric lens to compensate for the optical path difference of double-sided imaging.

[0010] The device for detecting the double-sided simultaneous complete equal optical path confocal imaging of semiconductor grains based on the polarization separation imaging method is characterized in that it includes a CMOS or CCD polarization camera, a telecentric imaging lens, a polarization cube beam splitter, semiconductor grains, and a transparent glass stage for placing the semiconductor grains, which are sequentially arranged in the optical path direction. On the optical path between the semiconductor grains and the polarization cube beam splitter, a side right-angle image rotation prism and a top surface right-angle image rotation prism are respectively provided. The side right-angle image rotation prism and the top surface right-angle image rotation prism are respectively located at the positive side and directly above the top surface of the semiconductor grains. The polarization cube beam splitter and the top surface right-angle image rotation prism are at the same horizontal height. The side right-angle image rotation prism and the polarization cube beam splitter 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 image rotation prism is aligned and glued to the first surface of the polarization cube beam splitter. The second right-angle surface of the side right-angle image rotation prism faces the side of the semiconductor grains. The inclined surface of the side right-angle image rotation prism is inclined with respect to the optical axis of the telecentric imaging lens. The two right-angle surfaces of the top surface right-angle image rotation prism face the top surface of the semiconductor grains and the second surface of the polarization cube beam splitter respectively. A coaxial external illumination source is provided beside the fourth surface opposite to the second surface of the polarization cube beam splitter. The top surface and the side of the semiconductor grains are respectively imaged in a completely equal optical path confocal manner on the sensor surface of the polarization camera through the right-angle image rotation prism and the polarization cube beam splitter, so as to obtain independent images of the two sides of the semiconductor grains on the CMOS or CCD polarization camera.

[0011] Further, the above-mentioned coaxial external illumination source is a monochromatic light or a quasi-monochromatic light source with a certain spectral bandwidth.

[0012] Further, the size of the above-mentioned top surface right-angle image rotation prism is 15*15*15mm, the size of the side right-angle image rotation prism is 15*15*15mm, and the size of the polarization cube beam splitter is 15*15*15mm.

[0013] Further, when the above-mentioned coaxial external illumination source passes through the polarization cube beam splitter, it is divided into two linearly polarized lights, the p-component and the s-component, with mutually perpendicular polarization directions. One linearly polarized light, i.e., the p-component, illuminates the top surface of the semiconductor grains to be measured through the top surface right-angle image rotation prism. And the other linearly polarized light, i.e., the s-component, illuminates the side of the semiconductor grains to be measured through the side right-angle image rotation prism. The two linearly polarized lights with mutually perpendicular polarization directions respectively illuminate two adjacent surfaces of the semiconductor grains.

[0014] Further, the two linearly polarized imaging light beams with mutually perpendicular polarization directions illuminate two adjacent surfaces of the semiconductor grains. The s-component of the imaging light beam on the top surface of the semiconductor grains enters the polarization camera after being reflected by the top surface right-angle image rotation prism and the polarization cube beam splitter. And the p-component of the imaging light beam on the side of the semiconductor grains enters the polarization camera after passing through the side right-angle image rotation prism and the polarization beam splitter. Independent images of the two sides are respectively obtained on the polarization camera.

[0015] Furthermore, the working distance WD of the above-mentioned top surface imaging optical path is WD = d / 2, where d is the length of the right-angled side of the prism; the polarization cube beam splitter is glued to the side right-angled image-rotating prism and their centers coincide. The working distance WD of the side imaging optical path is WD = D / 2 + d / 2, where D is the width of the transparent glass stage.

[0016] Furthermore, the polarization imaging of two adjacent surfaces of the semiconductor die is completely spatially coincident and both are output from the center of the upper end face of the polarization beam splitter; a CMOS or CCD polarization camera is used to respectively obtain the completely equal optical path confocal polarization imaging detection with the polarization directions of 0 degrees and 90 degrees separable for the top surface and the side imaging optical paths.

[0017] The semiconductor die double-sided simultaneous equal optical path confocal imaging detection method based on the polarization separation imaging method of the present invention is characterized in that: the device for the semiconductor die double-sided simultaneous completely equal optical path confocal imaging detection based on the polarization separation imaging method includes a CMOS or CCD polarization camera, a telecentric imaging lens, a polarization cube beam splitter, a semiconductor die, and a transparent glass stage for placing the semiconductor die, which are sequentially arranged in the optical path direction. On the optical path between the semiconductor die and the polarization cube beam splitter, a side right-angled image-rotating prism and a top surface right-angled image-rotating prism are respectively provided. The side right-angled image-rotating prism and the top surface right-angled image-rotating prism are respectively located at the positive side part and directly above the top surface of the semiconductor die. The polarization cube beam splitter and the top surface right-angled image-rotating prism are at the same horizontal height; the side right-angled image-rotating prism and the polarization cube beam splitter are located on the optical axis of the telecentric imaging lens. At the same time, the first right-angled surface of the side right-angled image-rotating prism is aligned and glued to the first surface of the polarization cube beam splitter. The second right-angled surface of the side right-angled image-rotating prism faces the side surface of the semiconductor die. The inclined surface of the side right-angled image-rotating prism is inclined with respect to the optical axis of the telecentric imaging lens. The two right-angled surfaces of the top surface right-angled image-rotating prism respectively face the top surface of the semiconductor die and the second surface of the polarization cube beam splitter; a coaxial external illumination light source is provided beside the fourth surface on the opposite side of the second surface of the polarization cube beam splitter. The top surface and the side surface of the semiconductor die are respectively imaged on the sensor surface of the polarization camera with completely equal optical path confocal imaging through the right-angled image-rotating prism and the polarization cube beam splitter, so as to obtain independent images of the two sides of the semiconductor die on the CMOS or CCD polarization camera;

[0018] Polarization illumination optical path: When the coaxial external illumination light source passes through the polarization cube beam splitter, it is divided into two linearly polarized lights with mutually perpendicular polarization directions, the p-component and the s-component; one polarized light, that is, the p-component, illuminates the top surface of the semiconductor die to be measured through the top surface right-angled image-rotating prism; and the other polarized light, that is, the s-component, illuminates the side surface of the semiconductor die to be measured through the side right-angled image-rotating prism. The two linearly polarized lights with mutually perpendicular polarization directions respectively illuminate two adjacent surfaces of the semiconductor die.

[0019] Polarization imaging optical path: Two linearly polarized light beams with perpendicular polarization directions illuminate two adjacent faces of a semiconductor grain to generate scattered light; the s-component of the imaging light beam on the top surface of the semiconductor grain is reflected by the right-angle image rotation prism on the top surface and the polarization cube beam splitter and enters the polarization camera, while the p-component of the imaging light beam on the side surface of the semiconductor grain is transmitted by the right-angle image rotation prism on the side surface and the polarization beam splitter and enters the polarization camera; the polarization imaging of the two adjacent faces of the semiconductor grain completely coincides spatially and is output from the center of the upper end face of the polarization beam splitter; a CMOS or CCD polarization camera is used to obtain a completely equal optical path confocal imaging detection with separable polarization directions of 0 degrees and 90 degrees for the imaging optical paths of the top surface and the side surface respectively.

[0020] Advantages of the device and method of the present invention:

[0021] 1) It can realize the simultaneous complete equal optical path confocal polarization imaging detection of two adjacent sides of the semiconductor grain to be measured, that is, △ = 0, without using a large depth of field telecentric lens to compensate for the optical path difference of the double-sided imaging of the grain.

[0022] 2) The utilization rate of the illumination light using the polarization cube beam splitter is as high as 100%, and the illumination efficiency of the double optical path and double polarized light illuminating the object is high (the light utilization rate of using an ordinary beam splitting prism is 50%).

[0023] 3) The double-sided polarization imaging of the semiconductor grain can achieve completely equal illuminance illumination.

[0024] 4) The polarization camera is used to separate the images of two adjacent sides simultaneously collected by two different polarization (0-degree and 90-degree polarization directions) imaging optical paths, and the image processing time is short and the speed is fast.

[0025] 5) The structure of the device for simultaneous polarization detection of two adjacent sides of the semiconductor grain is simple and compact, and the assembly and debugging are easy. Description of the drawings:

[0027] Figures 1-4 is an existing optical device for detecting adjacent faces of a semiconductor grain;

[0028] Among them, 1 is a black and white polarization camera, 2 is a telecentric imaging lens, 3a or 3b is an image rotation prism, 3 is an image combining optical element, 4 is a semiconductor grain, 5 is a transparent glass stage, 6 or 6a or 6b is an image rotation prism, 7 or 7a or 7b is a light source, and 8 is a controller;

[0029] Figure 5 is a schematic structural diagram of the device of the present invention;

[0030] Figure 6 is the structural principle of the polarization camera sensor for detecting four polarization information;

[0031] Figure 7 is the new structural principle of the polarization camera sensor for detecting two polarization information;

[0032] Figure 8 It is a schematic diagram of an embodiment of the device of the present invention; Specific implementation manner:

[0034] The device for double-sided simultaneous fully equal optical path confocal imaging detection of an optical device based on the polarization separation imaging method of the present invention includes a CMOS or CCD polarization camera 1, a telecentric imaging lens 2, a polarization cube beam splitter 3, a semiconductor die 4 (which can also be other objects to be detected), and a transparent glass stage 5 for placing the semiconductor die, arranged in sequence along the optical path direction. On the optical path between the semiconductor die 4 and the polarization cube beam splitter 3, a side right-angle image-rotating prism 6b and a top right-angle image-rotating prism 6a are respectively provided. The side right-angle image-rotating prism 6b and the top right-angle image-rotating prism 6a are respectively located at the positive side and directly above the top surface of the semiconductor die 4. The polarization cube beam splitter 3 and the top right-angle image-rotating prism 6a are at the same horizontal height; the side right-angle image-rotating prism 6b and the polarization cube beam splitter 3 are on the optical axis of the telecentric imaging lens. At the same time, the first right-angle surface 601 of the side right-angle image-rotating prism 6b is aligned and glued to the first surface of the polarization cube beam splitter. The second right-angle surface 602 of the side right-angle image-rotating prism faces the side surface of the semiconductor die. The inclined surface 603 of the side right-angle image-rotating prism is inclined with respect to the optical axis of the telecentric imaging lens. The two right-angle surfaces of the top right-angle image-rotating prism face the top surface 401 of the semiconductor die and the second surface 301 of the polarization cube beam splitter respectively; beside the fourth surface 302 on the opposite side of the second surface of the polarization cube beam splitter, a coaxial external illumination light source 7 is provided. The top surface 401 and the side surface 402 of the semiconductor die are respectively imaged on the sensor surface of the polarization camera with fully equal optical path confocal imaging through the right-angle image-rotating prism and the polarization cube beam splitter, so as to obtain independent images of both sides of the semiconductor die on the CMOS or CCD polarization camera.

[0035] Further, to meet the usage requirements, the above-mentioned coaxial external illumination light source can be a monochromatic light or a quasi-monochromatic light source with a certain spectral bandwidth.

[0036] Further, for reasonable design, the size of the above-mentioned top right-angle image-rotating prism is 15*15*15 mm, the size of the side right-angle image-rotating prism is 15*15*15 mm, and the size of the polarization cube beam splitter is 15*15*15 mm; the working distances of the top surface and side surface optical paths (i.e., the distance from the right-angle surface of the prism to the center of the die) are 7.5 and 30 mm respectively.

[0037] Among them, the polarization illumination optical path: When the above-mentioned coaxial external illumination light source passes through the polarization cube beam splitter, it is divided into two linearly polarized lights with mutually perpendicular polarization directions, the p-component and the s-component. One polarized light, that is, the p-component, illuminates the top surface of the semiconductor die to be measured through the top surface right-angle image-rotating prism; and the other polarized light, that is, the s-component, illuminates the side surface of the semiconductor die to be measured through the side surface right-angle image-rotating prism. The two linearly polarized lights with mutually perpendicular polarization directions illuminate two adjacent surfaces of the semiconductor die respectively.

[0038] Among them, the polarization imaging optical path: The two adjacent surfaces of the semiconductor die illuminated by linearly polarized lights with mutually perpendicular polarization directions generate scattered light; the s-component of the imaging light beam on the top surface of the semiconductor die enters the polarization camera through reflection by the top surface right-angle image-rotating prism and the polarization cube beam splitter, while the p-component of the imaging light beam on the side surface of the semiconductor die enters the polarization camera through transmission by the side surface right-angle image-rotating prism and the polarization beam splitter. Independent images of the two surfaces are respectively obtained on the polarization camera.

[0039] Furthermore, for reasonable design, the working distance WD of the above-mentioned top surface imaging optical path is d / 2, where d is the right-angle side length of the prism; the polarization cube beam splitter and the side surface right-angle image-rotating prism are glued together and centered. The working distance WD of the side surface imaging optical path is D / 2 + d / 2, where D is the width of the transparent glass stage.

[0040] The polarization imaging of the two adjacent surfaces of the semiconductor die completely coincides in space and both output from the center of the upper end surface of the polarization beam splitter; using a CMOS or CCD polarization camera, the polarization imaging detection with completely equal optical path and confocal, where the polarization directions of the top surface and the side surface imaging optical paths are separable at 0 degrees and 90 degrees, is obtained respectively.

[0041] The present invention relates to a method for detecting the double-sided simultaneous equal optical path confocal imaging of semiconductor grains based on polarization separation imaging method, which is characterized in that: the device for detecting the double-sided simultaneous complete equal optical path confocal imaging of semiconductor grains based on polarization separation imaging method includes a CMOS or CCD polarization camera, a telecentric imaging lens, a polarization cube beam splitter, a semiconductor grain, and a transparent glass stage for placing the semiconductor grain, which are sequentially arranged in the optical path direction. On the optical path between the semiconductor grain and the polarization cube beam splitter, a side right-angle image rotation prism and a top right-angle image rotation prism are respectively provided. The side right-angle image rotation prism and the top right-angle image rotation prism are respectively located at the positive side and directly above the top surface of the semiconductor grain. The polarization cube beam splitter and the top right-angle image rotation prism are at the same horizontal height; the side right-angle image rotation prism and the polarization cube beam splitter 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 image rotation prism is aligned and glued to the first surface of the polarization cube beam splitter. The second right-angle surface of the side right-angle image rotation prism faces the side surface of the semiconductor grain. The inclined surface of the side right-angle image rotation prism is inclined with respect to the optical axis of the telecentric imaging lens. The two right-angle surfaces of the top right-angle image rotation prism face the top surface of the semiconductor grain and the second surface of the polarization cube beam splitter respectively; a coaxial external illumination light source is provided beside the fourth surface on the back of the second surface of the polarization cube beam splitter. The top surface and the side surface of the semiconductor grain are respectively imaged on the sensor surface of the polarization camera with complete equal optical path confocal imaging through the right-angle image rotation prism and the polarization cube beam splitter, so as to obtain independent images of the two sides of the semiconductor grain on the CMOS or CCD polarization camera;

[0042] Polarization illumination optical path: When the coaxial external illumination light source passes through the polarization cube beam splitter, it is divided into two linearly polarized lights with mutually perpendicular polarization directions, namely the p-component and the s-component. One polarized light, that is, the p-component, illuminates the top surface of the semiconductor grain to be measured through the top right-angle image rotation prism; and the other polarized light, that is, the s-component, illuminates the side surface of the semiconductor grain to be measured through the side right-angle image rotation prism. The two linearly polarized lights with mutually perpendicular polarization directions illuminate two adjacent surfaces of the semiconductor grain respectively.

[0043] Polarization imaging optical path: The linearly polarized lights with mutually perpendicular polarization directions illuminate two adjacent surfaces of the semiconductor grain to generate scattered light; the s-component of the imaging light beam of the top surface of the semiconductor grain is reflected into the polarization camera through the top right-angle image rotation prism and the polarization cube beam splitter, while the p-component of the imaging light beam of the side surface of the semiconductor grain is transmitted into the polarization camera through the side right-angle image rotation prism and the polarization beam splitter; the polarization imaging of two adjacent surfaces of the semiconductor grain completely coincides in space and is output from the center of the upper end surface of the polarization beam splitter; Using a CMOS or CCD polarization camera, complete equal optical path confocal imaging detection with separable polarization directions of 0 degrees and 90 degrees for the top surface and the side surface imaging optical paths can be respectively obtained.

[0044] Advantages of the device and method of the present invention:

[0045] 1) It can realize the full equal optical path confocal polarization imaging detection of adjacent double sides of the semiconductor die to be measured, that is, △ = 0, without using a large depth of field telecentric lens to compensate for the optical path difference of double-sided imaging of the die.

[0046] 2) The utilization rate of the illumination light using a polarization cube beam splitter is as high as 100%, and the illumination efficiency of the double-path and double-polarization light illuminating the object is high (the light utilization rate of using an ordinary beam splitting prism is 50%).

[0047] 3) The double-sided polarization imaging detection of the semiconductor die can realize full equal illuminance illumination.

[0048] 4) The polarization camera is adopted to separate the images of adjacent double sides collected simultaneously by two different polarization (0-degree and 90-degree polarization directions) imaging optical paths, and the image processing time is short and the speed is fast.

[0049] 5) The structure of the device for simultaneously detecting the polarization imaging of adjacent double sides of the semiconductor die is simple and compact, and the assembly and debugging are easy.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or perform equivalent replacements for some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered within the scope of the technical solutions claimed by the present invention.

Claims

1. An apparatus for double-sided simultaneous complete equal optical path confocal imaging detection of semiconductor grains based on polarization separation imaging method, Characterized in that: It includes a CMOS or CCD polarization camera, a telecentric imaging lens, a polarization cube beam splitter, semiconductor grains, and a transparent glass stage for placing the semiconductor grains, which are sequentially arranged in the optical path direction. On the optical path between the semiconductor grains and the polarization cube beam splitter, a side right-angle image rotator and a top right-angle image rotator are respectively provided. The side right-angle image rotator and the top right-angle image rotator are respectively located at the positive side and directly above the top surface of the semiconductor grains. The polarization cube beam splitter and the top right-angle image rotator are at the same horizontal height; the side right-angle image rotator and the polarization cube beam splitter are on the optical axis of the telecentric imaging lens. At the same time, the first right-angle surface of the side right-angle image rotator is aligned and glued to the first surface of the polarization cube beam splitter. The second right-angle surface of the side right-angle image rotator faces the side surface of the semiconductor grains. The inclined surface of the side right-angle image rotator is inclined with respect to the optical axis of the telecentric imaging lens. The two right-angle surfaces of the top right-angle image rotator face the top surface of the semiconductor grains and the second surface of the polarization cube beam splitter respectively; on the side of the fourth surface opposite to the second surface of the polarization cube beam splitter, a coaxial external illumination light source is provided. The top surface and the side surface of the semiconductor grains are respectively imaged on the sensor surface of the polarization camera with complete equal optical path confocal imaging through the right-angle image rotators and the polarization cube beam splitter, so as to obtain independent images of the two sides of the semiconductor grains on the CMOS or CCD polarization camera.

2. The apparatus for double-sided simultaneous complete equal optical path confocal imaging detection of semiconductor grains based on polarization separation imaging method according to claim 1, Characterized in that: The coaxial external illumination light source is a monochromatic light or a quasi-monochromatic light source with a certain spectral bandwidth.

3. The apparatus for double-sided simultaneous complete equal optical path confocal imaging detection of semiconductor grains based on polarization separation imaging method according to claim 1, Characterized in that: The size of the top right-angle image rotator is 15*15*15mm, the size of the side right-angle image rotator is 15*15*15mm, and the size of the polarization cube beam splitter is 15*15*15mm.

4. The apparatus for double-sided simultaneous complete equal optical path confocal imaging detection of semiconductor grains based on polarization separation imaging method according to claim 1, Characterized in that: When the coaxial external illumination light source passes through the polarization cube beam splitter, it is divided into two linearly polarized lights with mutually perpendicular polarization directions, the p-component and the s-component; one polarized light, that is, the p-component, illuminates the top surface of the semiconductor grains to be measured through the top right-angle image rotator; and the other polarized light, that is, the s-component, illuminates the side surface of the semiconductor grains to be measured through the side right-angle image rotator.

5. The apparatus for double-sided simultaneous complete equal optical path confocal imaging detection of semiconductor grains based on polarization separation imaging method according to claim 4, Characterized in that: The s-component of the imaging beam of the top surface of the semiconductor grains is reflected into the polarization camera through the top right-angle image rotator and the polarization cube beam splitter, while the p-component of the imaging beam of the side surface of the semiconductor grains is transmitted into the polarization camera through the side right-angle image rotator and the polarization beam splitter, and independent images of the two sides are respectively obtained on the polarization camera.

6. The device for double-sided simultaneous full equal optical path confocal imaging detection of semiconductor grains based on polarization separation imaging method according to claim 1, characterized in that: The working distance WD of the top surface imaging optical path is d / 2, where d is the right-angled side length of the prism; the polarization cube beam splitter is glued to the side right-angled image rotation prism and is centered, and the working distance WD of the side imaging optical path is D / 2 + d / 2, where D is the width of the transparent glass stage.

7. The device for double-sided simultaneous full equal optical path confocal imaging detection of semiconductor grains based on polarization separation imaging method according to claim 1, characterized in that: The polarization imaging of two adjacent surfaces of the semiconductor grain is completely coincident in space and both are output from the center of the upper end surface of the polarization beam splitter; a CMOS or CCD polarization camera is used to obtain the full equal optical path confocal imaging detection with separable polarization directions of 0 degrees and 90 degrees for the top surface and the side imaging optical paths respectively.

8. A method for double-sided simultaneous equal optical path confocal imaging detection of semiconductor grains based on polarization separation imaging method, characterized in that: The device for double-sided simultaneous full equal optical path confocal imaging detection of semiconductor grains based on polarization separation imaging method includes a CMOS or CCD polarization camera, a telecentric imaging lens, a polarization cube beam splitter, a semiconductor grain, and a transparent glass stage for placing the semiconductor grain, which are sequentially arranged in the optical path direction. A side right-angled image rotation prism and a top surface right-angled image rotation prism are respectively provided on the optical path between the semiconductor grain and the polarization cube beam splitter. The side right-angled image rotation prism and the top surface right-angled image rotation prism are respectively located at the positive side and directly above the top surface of the semiconductor grain. The polarization cube beam splitter and the top surface right-angled image rotation prism are at the same horizontal height; the side right-angled image rotation prism and the polarization cube beam splitter are located on the optical axis of the telecentric imaging lens. At the same time, the first right-angled surface of the side right-angled image rotation prism is aligned and glued to the first surface of the polarization cube beam splitter, the second right-angled surface of the side right-angled image rotation prism faces the side surface of the semiconductor grain, and the inclined surface of the side right-angled image rotation prism is inclined with respect to the optical axis of the telecentric imaging lens. The two right-angled surfaces of the top surface right-angled image rotation prism respectively face the top surface of the semiconductor grain and the second surface of the polarization cube beam splitter; a coaxial external illumination light source is provided beside the fourth surface opposite to the second surface of the polarization cube beam splitter. The top surface and the side surface of the semiconductor grain are respectively imaged in a full equal optical path confocal manner on the sensor surface of the polarization camera through the right-angled image rotation prism and the polarization cube beam splitter, so as to obtain independent images of the two sides of the semiconductor grain on the CMOS or CCD polarization camera; Polarization illumination optical path: When the coaxial external illumination light source passes through the polarization cube beam splitter, it is divided into two linearly polarized lights with mutually perpendicular polarization directions, the p-component and the s-component; one polarized light, that is, the p-component, illuminates the top surface of the semiconductor grain to be measured through the top surface right-angled image rotation prism; and the other polarized light, that is, the s-component, illuminates the side surface of the semiconductor grain to be measured through the side right-angled image rotation prism. Polarization imaging optical path: Two linearly polarized imaging light beams with perpendicular polarization directions illuminate two adjacent faces of a semiconductor grain to generate scattered light; the s-component of the imaging light beam on the top surface of the semiconductor grain is reflected by the right-angle image-rotating prism on the top surface and the polarization cube beam splitter and enters the polarization camera, while the p-component of the imaging light beam on the side surface of the semiconductor grain is transmitted by the right-angle image-rotating prism on the side surface and the polarization beam splitter and enters the polarization camera; moreover, the polarization imaging of the two adjacent faces of the semiconductor grain completely coincides spatially and is output from the center of the upper end face of the polarization beam splitter; a CMOS or CCD polarization camera is used to respectively obtain the completely equal optical path confocal polarization imaging detection with separable polarization directions of 0 degrees and 90 degrees for the top surface and side surface imaging optical paths.

Images