Illumination compensation device and method for simultaneous detection of defects on both sides of semiconductor grains

Abstract

The present invention relates to an illumination compensation device for simultaneous detection of defects on both sides of semiconductor crystal grains, comprising an optical detection device, a right-angle image rotation prism is arranged on the optical path of the optical detection device, and a right-angle illumination compensation prism and a compensation illumination light source are arranged in sequence below the right-angle side of the bottom surface of the semiconductor crystal grain. The structure is simple, and a light beam emitted from the compensation illumination light source is incident on the right-angle side of the right-angle illumination compensation prism through the right-angle illumination compensation prism. After the light beam is refracted, it is incident on the inclined surface of the right-angle image rotation prism and does not meet the total reflection condition, but is emitted from the inclined surface and illuminates the bottom surface of the semiconductor crystal grain through a transparent glass stage, thereby realizing illumination compensation for the bottom surface of the semiconductor crystal grain.

Description

Technical Field

[0001] The invention relates to an illumination compensation device and method for simultaneous detection of double-sided defects of semiconductor crystal grains, belonging to the field of optical detection and machine vision. Background Art

[0002] Traditional machine vision optical inspection devices mainly include cameras, imaging lenses, lighting sources, image processing algorithm software, electrical control, mechanical structures, objects to be tested (such as semiconductor grains), etc. The object is illuminated by a light source, and the object obtains the image of the object on the CCD detector surface through an optical imaging lens. The image is transmitted to the computer through an image acquisition card and an AD conversion module. Finally, the required image information is obtained through digital image processing technology. According to pixel distribution, brightness, color and other information, the size, shape and color are judged and measured, and the equipment operation on site is controlled. If two surfaces of a single object are to be inspected at the same time, the current common inspection method is that one camera occupies one station to inspect one surface. If two or more surfaces need to be inspected at the same time, multiple cameras need to be used to occupy multiple stations for inspection, which results in a large installation space for the mechanism, and multiple sets of mechanism installation modules and circuit modules are required, which increases the installation complexity and reduces the system reliability. Traditional machine vision optical inspection devices based on single-lens single-side inspection technology have economic and technical limitations such as inspection efficiency, cost-effectiveness, and complex structure. In addition, in the online detection of the object to be measured, due to the jitter of the object in the optical axis direction of the imaging lens, or due to the thickness tolerance of the object to be measured, the image position of different objects on the CCD receiving plane changes, resulting in changes in clarity. Usually, an object-side telecentric imaging lens with a certain depth of field is used to solve this problem.

[0003] In order to solve the above shortcomings, the prior art proposes an optical device for simultaneously detecting both sides of semiconductor grains, such as prior art patents 2019101574716 and 2019102070162.

[0004] However, the above optical device has the problem of unequal illumination in double-sided detection. That is, although the two optical paths of the double-sided detection system can obtain equal optical path imaging on the object side, the two light paths pass through different numbers of optical elements and different times of reflection and refraction. The illumination of the two light beams with equal intensity will be different when they reach the surface of the grain to be tested, which makes image processing difficult for the simultaneous detection of double-sided defects.

[0005] This case was created to solve the problem of unequal illumination in double-sided detection in existing optical devices. Summary of the invention

[0006] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide an illumination compensation device and method for simultaneous detection of double-sided defects of semiconductor grains, which is not only simple in structure but also convenient and efficient.

[0007] In order to solve the above technical problems, the technical solution of the present invention is: an illumination compensation device for simultaneous detection of double-sided defects of semiconductor grains, including an optical detection device, a right-angle image rotation prism is arranged on the optical path of the optical detection device, and a right-angle illumination compensation prism and a compensation illumination light source are arranged in sequence below the right-angle side of the bottom surface of the semiconductor grain.

[0008] Preferably, the inclined surface of the right-angle illumination compensation prism is parallel to the right-angle side of the right-angle image rotation prism on the bottom surface side of the semiconductor crystal grain.

[0009] Preferably, a rotation axis for rotating the right-angle illumination compensation prism to adjust the angle is provided on one of the vertices of the right-angle illumination compensation prism.

[0010] Preferably, a rotating shaft for rotating and adjusting the angle of the compensation illumination light source is provided in the middle of the compensation illumination light source.

[0011] Preferably, the optical detection device is a device for optically detecting both the front and back surfaces of a semiconductor grain at the same time, comprising: a camera containing a CCD or CMOS sensor, a telecentric imaging lens, an external annular illumination light source, a semiconductor grain to be tested and a transparent glass stage, and a right-angle image rotation prism are arranged in sequence from top to bottom in the direction vertical to the light path; the camera and the telecentric imaging lens face downward and are arranged above the transparent glass stage; the inclined surface of the right-angle image rotation prism faces the transparent glass stage and is parallel to the transparent glass stage, and the right-angle image rotation prism is arranged below the transparent glass stage; the right-angle image rotation prism, the telecentric imaging lens and the camera form a coaxial optical system.

[0012] Preferably, the semiconductor crystal grain is located on the left side of the right-angle image rotation prism, and the right-angle illumination compensation prism and the compensation illumination light source are located on the lower left side of the right-angle image rotation prism.

[0013] Preferably, the optical detection device is a device for simultaneously performing optical detection on two adjacent surfaces of a semiconductor grain, comprising: arranged in sequence in the horizontal direction: a horizontal transparent glass stage, a beam splitter at a 45° angle and an illumination light source, as well as a camera and a telecentric imaging lens above, and a right-angle image rotation prism below; the camera and the telecentric imaging lens are arranged downward above the beam splitter; the right-angle image rotation prism is arranged below the transparent glass stage and the beam splitter, and the inclined surface is parallel to and facing the transparent glass stage.

[0014] Preferably, the semiconductor crystal grain is located on the left side of the right-angle image rotation prism, and the right-angle illumination compensation prism and the compensation illumination light source are located on the lower left side of the right-angle image rotation prism.

[0015] Preferably, the optical detection device is a device for realizing simultaneous detection of the top and bottom surfaces of semiconductor grains based on a rotating image lens, comprising: a transparent glass stage for carrying the semiconductor grains to be inspected, a small right-angle rotating image prism with two right-angle surfaces arranged opposite to each other on a first side of the transparent glass stage, and an illumination light source, a telecentric imaging lens and a camera arranged on a second side of the transparent glass stage; the other right-angle surfaces of the two small right-angle rotating image prisms face the transparent glass stage and are parallel to the transparent glass stage; an image rotating lens is provided between the right-angle surfaces opposite to each other of the two small right-angle rotating image prisms, and the image rotating lens is a convex lens; the two small right-angle rotating image prisms form a large right-angle rotating image prism, the semiconductor grain is located above the right-angle side of the small right-angle rotating image prism on the left side of the two small right-angle rotating image prisms, and the right-angle illumination compensation prism and the compensation illumination light source are located at the lower left of the large right-angle rotating image prism.

[0016] A compensation method for an illumination compensation device for simultaneous detection of defects on both sides of a semiconductor crystal grain is performed according to the following steps: a light beam emitted from a compensation illumination light source is incident on the right-angle side of a right-angle image-turning prism through a right-angle illumination compensation prism; the light beam is refracted and incident on the inclined surface of the right-angle image-turning prism, but does not meet the total reflection condition. Instead, the light beam is emitted from the inclined surface and illuminates the bottom surface of the semiconductor crystal grain through a transparent glass stage, thereby realizing illumination compensation for the bottom surface of the semiconductor crystal grain.

[0017] Compared with the prior art, the present invention has the following beneficial effects: the structure is simple, the light beam emitted from the compensation illumination light source is incident on the right-angle side of the right-angle image-turning prism through the right-angle illumination compensation prism, the light beam is refracted and incident on the inclined surface of the right-angle image-turning prism, and does not meet the total reflection condition, but is emitted from the inclined surface and illuminates the bottom surface of the semiconductor crystal grain through the transparent glass stage, thereby realizing illumination compensation for the bottom surface of the semiconductor crystal grain and achieving the purpose of equal illumination illumination.

[0018] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of Example 1 of the present invention.

[0020] Figure 2 Schematic diagram of the structure of Example 1A of the present invention.

[0021] Figure 3 Schematic diagram of the structure of Example 1B of the present invention.

[0022] Figure 4 This is a schematic diagram of the structure of Example 2 of the present invention.

[0023] Figure 5 This is a schematic diagram of the structure of Example 3 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below with reference to the accompanying drawings for detailed description.

[0025] All embodiments of the present invention are Figures 1 to 5 As shown:

[0026] An illumination compensation device for simultaneous detection of defects on both sides of a semiconductor crystal grain comprises an optical detection device, a right-angle image rotation prism 1 is arranged on the optical path of the optical detection device, and a right-angle illumination compensation prism 3 and a compensation illumination light source 4 are arranged in sequence below the right-angle side of the bottom side of the semiconductor crystal grain 2. In the existing optical devices for simultaneous detection of defects on both sides (bottom and top, bottom and side) of semiconductor crystal grains, the conventional illumination light sources used include an annular illumination light source, an external coaxial illumination light source or a built-in coaxial illumination light source. A common problem in these detection devices is that the illumination illumination of the bottom surface of the crystal grain is 10-18% weaker than that of the top (or side). The main source of this illumination difference is the reflection loss of the two surfaces of the transparent glass stage and the absorption of the glass material, as well as the double reflection loss of the inclined surface of the right-angle image rotation prism. In order to obtain equal illumination illumination of the two surfaces, it is usually necessary to perform appropriate illumination compensation on the bottom surface of the semiconductor crystal grain.

[0027] In the embodiment of the present invention, the inclined surface of the right-angle illumination compensation prism is parallel to the right-angle side of the right-angle image rotation prism on the bottom surface side of the semiconductor crystal grain.

[0028] Among them, Figure 1 As shown, in Example 1 of the present invention, the optical detection device is a device for optically detecting both the front and back surfaces of a semiconductor grain at the same time, comprising: a camera 5 containing a CCD or CMOS sensor, a telecentric imaging lens 6, an external annular lighting source 7, a semiconductor grain to be tested and a transparent glass stage 8, and a right-angle image rotation prism are arranged in sequence from top to bottom in the direction of the vertical light path; the camera and the telecentric imaging lens face downward and are arranged above the transparent glass stage; the inclined surface of the right-angle image rotation prism faces the transparent glass stage and is parallel to the transparent glass stage, and the right-angle image rotation prism is arranged below the transparent glass stage; the right-angle image rotation prism, the telecentric imaging lens and the camera form a coaxial optical system.

[0029] In Example 1 of the present invention, the semiconductor crystal grain is located on the left side of the right-angle image rotation prism, and a main illumination beam emitted from the illumination light source directly illuminates the top surface of the semiconductor crystal grain, and another main illumination beam is first reflected and redirected by the right-angle image rotation prism and then illuminates the bottom surface of the crystal grain to be measured on the transparent glass stage. Obviously, since the two illumination beams are reflected and refracted for different times, the illumination on the top surface and the bottom surface of the semiconductor crystal grain is also different, and the illumination on the bottom surface is usually 10-18% weaker than that on the top surface. Therefore, the right-angle illumination compensation prism and the compensation illumination light source are located at the lower left of the right-angle image rotation prism to perform illumination compensation on the bottom surface of the semiconductor crystal grain. An acute angle of the right-angle illumination compensation prism is about 30 degrees, and its right-angle side makes an angle of 15 degrees with the horizontal direction. The principle for selecting the angle of the right-angle illumination compensation prism is that the light beam emitted from the compensation illumination light source is incident on the right-angle side of the right-angle image rotation prism, and after refraction, the light beam incident on the inclined surface of the right-angle image rotation prism does not meet the total reflection condition, but is emitted from the inclined surface and illuminates the bottom surface of the crystal grain through the transparent glass stage.

[0030] like Figure 2 As shown, in Example 1A of the present invention, in order to optimize the lighting on the top and bottom surfaces of the grain, a rotating shaft 9 for rotating and adjusting the angle of the right-angle lighting compensation prism is provided on one of the vertices of the right-angle lighting compensation prism, thereby changing the incident angle of the illumination light beam on the bottom surface of the grain to obtain the best scattering compensation lighting effect on the bottom surface of the grain.

[0031] like Figure 3 As shown, in Example 1B of the present invention, in order to optimize the lighting on the top and bottom surfaces of the grain, a rotating shaft for rotating and adjusting the angle of the compensation lighting source is provided in the middle of the compensation lighting source, thereby changing the angle of the lighting beam on the bottom surface of the grain, thereby obtaining the best scattered compensation lighting effect on the bottom surface of the grain.

[0032] Embodiment 1A and embodiment 1B can be set at the same time, that is, when in use, you can choose to fix the compensation lighting light source to adjust the right-angle lighting compensation prism, or the right-angle lighting compensation prism to fix the compensation lighting light source, or adjust the compensation lighting light source and the right-angle lighting compensation prism at the same time to obtain the best scattering compensation lighting effect on the bottom surface of the grain.

[0033] like Figure 4 As shown, in Embodiment 2 of the present invention, the optical detection device is a device for optically detecting two adjacent surfaces of a semiconductor grain at the same time, comprising: a horizontal transparent glass stage, a beam splitter 10 at a 45° angle and an illumination light source, as well as a camera and a telecentric imaging lens above, and a right-angle image rotation prism below, which are arranged in sequence in the horizontal direction; the camera and the telecentric imaging lens are arranged downward above the beam splitter; the right-angle image rotation prism is arranged below the transparent glass stage and the beam splitter, and the inclined surface is parallel to the transparent glass stage and faces the transparent glass stage.

[0034] In Embodiment 2 of the present invention, the semiconductor crystal grain is located on the left side of the right-angle image rotation prism, and the right-angle illumination compensation prism and the compensation illumination light source are located on the lower left side of the right-angle image rotation prism; a rotation axis (not shown in the figure) for rotating and adjusting the angle of the right-angle illumination compensation prism may also be provided on one of the vertices of the right-angle illumination compensation prism; a rotation axis (not shown in the figure) for rotating and adjusting the angle of the compensation illumination light source may also be provided in the middle of the compensation illumination light source.

[0035] like Figure 5 As shown, in Embodiment 3 of the present invention, the optical detection device is a device for realizing simultaneous detection of the top and bottom surfaces of semiconductor crystal grains based on a rotating image lens, comprising: a transparent glass stage for carrying the semiconductor crystal grains to be inspected, a small right-angle rotating image prism 11 with two right-angle surfaces facing each other on a first side of the transparent glass stage, and an illumination light source, a telecentric imaging lens and a camera arranged on a second side of the transparent glass stage; the other right-angle surfaces of the two small right-angle rotating image prisms face the transparent glass stage and are parallel to the transparent glass stage; an image rotating lens is arranged between the right-angle surfaces facing each other of the two small right-angle rotating image prisms. Lens 12, the image-transmitting lens is a convex lens; two small right-angle image-transmitting prisms form a large right-angle image-transmitting prism, the semiconductor grain is located above the right-angle side of the small right-angle image-transmitting prism on the left side of the two small right-angle image-transmitting prisms, and the right-angle illumination compensation prism and the compensation illumination light source are located at the lower left of the large right-angle image-transmitting prism; a rotation shaft (not shown in the figure) for rotating and adjusting the angle of the right-angle illumination compensation prism may also be provided on one of the vertices of the right-angle illumination compensation prism; a rotation shaft (not shown in the figure) for rotating and adjusting the angle of the compensation illumination light source may also be provided in the middle of the compensation illumination light source.

[0036] In the third embodiment of the present invention, the combined image-reversing optical system composed of two small right-angle image-reversing prisms and an image-reversing lens can realize basic equal optical path imaging of the top and bottom surfaces, reducing the detection system's requirement for a large depth of field of the imaging lens, even if the depth of field is less than or equal to the thickness of the grain. The bottom surface imaging of the semiconductor grain is located at a horizontal position beside the transparent glass stage and close to the bottom surface of the semiconductor grain, and the bottom surface imaging position K of the semiconductor grain can be adjusted by adjusting the distance between the image-reversing lens and the right-angle surfaces of the two small right-angle image-reversing prisms. By making the bottom surface imaging of the semiconductor grain located at a horizontal position beside the transparent glass stage and close to the bottom surface of the semiconductor grain, the detection system's requirement for a large depth of field of the imaging lens can be reduced, the cost of the imaging lens can be reduced, and the difficulty of shooting and image processing can be reduced. The combined image-relay optical system composed of the right-angle image-relay prism and the image-relay lens, when the bottom surface of the semiconductor crystal grain is located at the twice focal position of the object side of the combined image-relay optical system, a real image of the bottom surface of the semiconductor crystal grain is obtained at the twice focal position of the image side and the lateral magnification is 1; the secondary images of the top surface and bottom surface of the semiconductor crystal grain pass through the telecentric imaging lens respectively and finally form real images of the top surface and bottom surface in the left half area and the right half area of ​​the camera sensor.

[0037] A compensation method for an illumination compensation device for simultaneous detection of defects on both sides of a semiconductor crystal grain is performed according to the following steps: a light beam emitted from a compensation illumination light source is incident on the right-angle side of a right-angle image-turning prism through a right-angle illumination compensation prism; the light beam is refracted and incident on the inclined surface of the right-angle image-turning prism, but does not meet the total reflection condition. Instead, the light beam is emitted from the inclined surface and illuminates the bottom surface of the semiconductor crystal grain through a transparent glass stage, thereby realizing illumination compensation for the bottom surface of the semiconductor crystal grain.

[0038] The present invention can not only compensate for the illumination when inspecting semiconductor crystal grains, but also can compensate for the illumination when inspecting the bottom surface of other objects placed on a transparent glass stage.

[0039] The present invention is not limited to the above-mentioned best implementation mode. Anyone can derive other various forms of illumination compensation devices and methods for simultaneous detection of defects on both sides of semiconductor grains under the enlightenment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. An illumination compensation device for simultaneous detection of defects on both sides of a semiconductor grain, comprising an optical detection device, a right-angle image rotation prism is arranged on the optical path of the optical detection device, and is characterized in that: The right-angle image rotation prism is provided with a right-angle illumination compensation prism and a compensation illumination light source in sequence below the right-angle side of the bottom surface of the semiconductor crystal grain; The optical detection device is a device for realizing simultaneous detection of the top and bottom surfaces of semiconductor crystal grains based on a rotating image lens, comprising: a transparent glass stage for carrying semiconductor crystal grains to be inspected, a small right-angle rotating image prism with two right-angle surfaces arranged opposite to each other on a first side of the transparent glass stage, and an illumination light source, a telecentric imaging lens and a camera arranged on a second side of the transparent glass stage; the other right-angle surfaces of the two small right-angle rotating image prisms face the transparent glass stage and are parallel to the transparent glass stage; an image rotating lens is arranged between the right-angle surfaces opposite to each other of the two small right-angle rotating image prisms, and the image rotating lens is a convex lens; the two small right-angle rotating image prisms form a large right-angle rotating image prism, the semiconductor crystal grain is located above the right-angle side of the small right-angle rotating image prism on the left side of the two small right-angle rotating image prisms, and the right-angle illumination compensation prism and the compensation illumination light source are located at the lower left of the large right-angle rotating image prism.

2. The illumination compensation device for simultaneous detection of defects on both sides of semiconductor grains according to claim 1, characterized in that: The inclined surface of the right-angle illumination compensation prism is parallel to the right-angle side of the right-angle image transfer prism on the bottom surface side of the semiconductor crystal grain.

3. The illumination compensation device for simultaneous detection of defects on both sides of semiconductor grains according to claim 1, characterized in that: A rotating shaft for rotating and adjusting the angle of the right-angle lighting compensation prism is arranged on one of the vertices of the right-angle lighting compensation prism.

4. The illumination compensation device for simultaneous detection of defects on both sides of semiconductor grains according to claim 1, characterized in that: A rotating shaft for adjusting the rotation angle of the compensation lighting source is arranged in the middle of the compensation lighting source.

5. A compensation method for an illumination compensation device for simultaneous detection of defects on both sides of a semiconductor grain according to any one of claims 1 to 4, characterized in that: Proceed in the following steps: a light beam emitted from a compensation illumination light source is incident on the right-angle side of a right-angle image-turning prism through a right-angle illumination compensation prism; after refraction, the light beam is incident on the inclined surface of the right-angle image-turning prism and does not satisfy the total reflection condition; instead, the light beam is emitted from the inclined surface and illuminates the bottom surface of the semiconductor crystal grain through a transparent glass stage, thereby achieving illumination compensation for the bottom surface of the semiconductor crystal grain.

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