CN218349762U - Detection equipment - Google Patents

Abstract

The utility model discloses a detection device, which comprises a bright field illumination component and an information acquisition component, wherein the bright field illumination component is used for illuminating an object to be detected, and the information acquisition component is used for acquiring and processing reflected light of the object to be detected; the utility model provides an information acquisition subassembly is used for gathering and handling the reverberation of determinand. Information acquisition subassembly includes imaging lens and camera usually, the utility model provides an imaging lens is object space telecentric structure's imaging lens. Therefore, the chief rays corresponding to the imaging lenses are parallel, the problem that the reflectivity of the multilayer on the back of the wafer changes along with the angle is avoided, the uniformity is better, and the detection precision is improved. Meanwhile, when the bright field illumination component is in a working state, the imaging light path of the imaging lens is perpendicular to the object to be detected and is parallel to the main light path of the light outlet of the illumination component, so that the illumination efficiency of the bright field illumination component can be greatly improved, a bright field image with high contrast is obtained, and the accuracy of a detection result is improved.

Description

Detection equipment

Technical Field

The utility model relates to a detect technical field, especially relate to a check out test set.

Background

Referring to fig. 1, in order to improve the detection accuracy, the conventional wafer detection apparatus generally has a bright field light source 2', a dark field light source 3', and an imaging device 4', and can also meet the detection requirements of different types of defects of the wafer 1'.

Referring to fig. 2, in the conventional wafer inspection apparatus, there is a problem that an image 5' captured by each optical path is bright at the center and dark at both sides, which results in generation of seams at the image splicing positions after splicing. This phenomenon affects the false judgment of the defect judgment of the wafer back side by a person, and also reduces the detection of the sensitivity of the defect in the automatic recognition of the system.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a check out test set, this check out test set can acquire the even image of luminance to improve and detect the precision.

The utility model provides a detection device, which comprises a bright field illumination component and an information acquisition component, wherein the bright field illumination component is used for illuminating an object to be detected, and the information acquisition component is used for acquiring and processing reflected light of the object to be detected; the information acquisition component is provided with an imaging lens of an object space telecentric structure, and when the bright field illumination component is in a working state, an imaging light path of the imaging lens is perpendicular to a surface to be detected of the object to be detected, and the imaging light path of the imaging lens is parallel to a main light path of a light outlet of the illumination component.

Optionally, the position of the bright field illumination component may be selectively switched between a first station and a second station, and when the bright field illumination component is located at the first station, a chief ray of a light outlet of the bright field illumination component strikes a field of view position of an imaging optical path of the imaging lens and coincides with an imaging chief ray; when the bright field illumination component is positioned at the second station, the bright field illumination component exits the imaging light path.

Optionally, bright field lighting part includes light source and beam splitter, the light process that the light source jetted out the partial vertical irradiation extremely behind the beam splitter of part the determinand, the process reflected light part warp that the determinand reflects the beam splitter transmission gets into imaging lens, the beam splitter with the contained angle that forms between the light that the light source jetted out is 45.

Optionally, the device further comprises a dark field illumination component, and an incident angle between a main optical axis of a light outlet of the dark field illumination component and a surface to be measured of the object is 70 to 85 °.

Optionally, the light source of the bright field illumination component or/and the dark field illumination component includes a monochromatic light source, an RGB three-color light source, or an RGBW four-color light source, and the light source color of the bright field illumination component or/and the dark field illumination component is selected according to the target image signal-to-noise ratio.

Optionally, the detection apparatus further includes a driving component configured to drive the object to be measured to translate along a predetermined track; the information acquisition assembly is provided with at least one imaging light path, each imaging light path corresponds to a view field, and the information acquisition assembly is configured to scan the object to be detected in the translation process of the object to be detected.

Optionally, the object to be measured is a wafer, and the driving component can drive the wafer to translate along a first direction and a second direction, where the first direction and the second direction are perpendicular to each other.

Optionally, the information acquisition assembly has at least two imaging optical paths, the field of view corresponding to the imaging optical path is a line field of view, and each of the line fields of view is collinear.

Optionally, the information collecting assembly includes imaging device units corresponding to the imaging optical paths, and each of the imaging device units includes the imaging lens and the line scanning camera.

Optionally, the information acquisition assembly has two imaging light paths, and the coverage length of the two line view fields corresponding to the two imaging light paths is greater than or equal to the radius of the wafer.

The utility model provides an information acquisition subassembly is used for gathering and handling the reverberation of determinand. Information acquisition subassembly includes imaging lens and camera usually, the utility model provides an imaging lens is object space telecentric structure's imaging lens. Therefore, the chief rays corresponding to the imaging lenses are parallel, the problem that the reflectivity of the multilayer on the back of the wafer changes along with the angle is avoided, the uniformity is better, and the detection precision is improved.

Meanwhile, when the bright field illumination component is in a working state, the imaging light path of the imaging lens is perpendicular to the object to be detected and is parallel to the main light path of the light outlet of the illumination component, so that the illumination efficiency of the bright field illumination component can be greatly improved, a bright field image with high contrast is obtained, and the accuracy of a detection result is improved.

Drawings

FIG. 1 is a schematic diagram of a wafer inspection apparatus in the prior art;

FIG. 2 is a scanned image of the wafer inspection apparatus shown in FIG. 1;

fig. 3 is a schematic structural diagram of an embodiment of the detection apparatus provided in the present invention;

FIG. 4 is a front view of the detection apparatus shown in FIG. 3;

FIG. 5 is a schematic view of the bright field illumination component of the inspection apparatus of FIG. 3 in a first station;

FIG. 6 is a schematic view of the dark field illumination component of the inspection apparatus of FIG. 3 in an operational state;

fig. 7 is a top view of the inspection apparatus provided in the present invention, wherein a translation motion path diagram of a wafer is shown;

fig. 8 is a schematic diagram of an image obtained after the wafer is scanned by the detection apparatus provided by the present invention.

Wherein the reference numerals in figures 1 and 2 illustrate:

a wafer 1'; a bright field light source 2'; dark field light source 3'; an imaging section 4'; image 5';

wherein the reference numbers in figures 3 to 8 illustrate:

a wafer 1; an image 6;

a bright field lighting part 2; a light source 21; a spectroscope 22;

a dark field illumination section 3;

an information acquisition component 4; an image forming apparatus unit 40; an imaging lens 41; a line scanning camera 42; a first field of view 4A; a second field of view 4B;

a support member 5;

imaging chief ray Z2, bright field chief ray Z1 and dark field illumination ray Z3.

Detailed Description

Aiming at the technical problem that the image 5 'spliced by the current wafer 1' in the background technology has a seam at the splicing position, the intensive research is carried out, and the research finds that: in the current scheme, object space view field chief rays are not parallel to each other, please refer to fig. 1, where fig. 1 shows two optical paths, where the two optical path view fields are connected in end-to-end to form a longer linear view field, but the chief rays of each view field are not parallel to each other, for example, edge chief rays S1 and S2 in one of the optical paths are obviously not parallel to each other, the larger the view field is, only central view field chief rays are used to be parallel to the central axis of the lens, the larger the view field is, the larger the angle between the chief rays and the central axis of the lens is, and the angle between the chief rays in the edge view field is the largest.

The reflective properties of the back side of the wafer are usually specular reflection, and are also accompanied by multilayer films, which have an interference reflection effect on light. The effect causes the reflectivity and the reflection spectrum to change with the angle, for the non-telecentric imaging structure, the main ray angles of different fields of view are different, resulting in the final reflectivity changing with the field of view, and the finally formed scanning image please refer to fig. 2.

On the basis of the above findings, the present application has made a large number of experiments, and finally proposes a technical means for solving the above technical solutions.

In order to make the technical field better understand the solution of the present invention, the following detailed description is given with reference to the accompanying drawings and the detailed description.

Without loss of generality, the object to be tested is taken as a wafer for description, and it can be understood that when the object to be tested is other components, the detection principle and process are similar to that, and the description is not repeated.

Referring to fig. 3 to 8, fig. 3 is a schematic structural diagram of an embodiment of a detection apparatus provided in the present invention; FIG. 4 is a front view of the detection apparatus shown in FIG. 3; FIG. 5 is a schematic view of the bright field illumination component of the inspection apparatus of FIG. 3 in a first station; FIG. 6 is a schematic view of a dark field illumination assembly of the inspection apparatus shown in FIG. 3 in an operating state; fig. 7 is a top view of the inspection apparatus provided in the present invention, wherein a translation motion path diagram of a wafer is shown; fig. 8 is a schematic diagram of an image obtained after the wafer is scanned by the detection device provided by the present invention.

In this embodiment, the inspection apparatus includes a bright field illumination component, a dark field illumination component, and an information acquisition assembly.

The bright field lighting component 2 is used for illuminating an object to be measured, the bright field lighting component 2 may include a light source 21, and the light source 21 may be a monochromatic light source or one or more of an RGB (RGB is an initial letter of an english word Red, green, or Blue, and chinese means Red, green, and Blue) three-color light source or an RGBW (RGBW is an initial letter of an english word Red, green, blue, and White, and chinese means Red, green, blue, and White) four-color light source. The light source may be an LED lamp, but may also be other types of lamps. The light source color can be selected reasonably according to the specific object to be tested and the test environment, as long as the target signal-to-noise ratio can be provided.

Similarly, the light source of the dark-field lighting component 3 may be selected with reference to the bright-field lighting component 2, and may also be one or more of a monochromatic light source, or a RGB (RGB is the first letter of the english word Red, green, or Blue, and chinese means Red, green, and Blue) three-color light source, or an RGBW (RGBW is the first letter of the english word Red, green, blue, and White, and chinese means Red, green, blue, and White) four-color light source. The light source may be an LED lamp, but may be other types of lamps. The selection of the light source color can be reasonably selected according to a specific object to be tested and a test environment, and only the target signal-to-noise ratio can be provided.

The bright field illumination component 2 and the dark field illumination component 3 are different in that a bright field principal ray Z1 of the bright field illumination component 2 enters the information acquisition component 4 after being reflected by the object to be measured so as to obtain a brighter image 6 of the object to be measured, and a reflected ray of a dark field principal ray Z3 emitted by the dark field illumination component 3 does not enter the information acquisition component 4 but enters the information acquisition component 4 through a diffuse reflection ray on the surface of the object to be measured, so that the image of the object to be measured is obtained. The surface defect of the object to be measured can be known relatively comprehensively by analyzing the surface of the object to be measured by combining the images obtained under the two situations of the bright field illumination component 2 and the dark field illumination component 3.

The utility model provides an information acquisition subassembly 4 is used for gathering and handling the reverberation of determinand. The information collecting assembly 4 generally includes an imaging lens 41 and a camera 42, and the imaging lens 41 in the present invention is an imaging lens with an object-side telecentric structure. Therefore, the chief rays corresponding to the imaging lenses 41 are parallel, the problem that the reflectivity of multiple layers on the back of the wafer changes along with the angle is avoided, and the uniformity is better.

Meanwhile, when the bright field illumination component 2 is in a working state, the imaging light path of the imaging lens 41 is perpendicular to the surface to be detected of the object to be detected, and the imaging light path of the imaging lens 41 is parallel to the main light path of the light outlet of the bright field illumination component, so that the illumination efficiency of the bright field illumination component 2 can be greatly improved, a bright field image with high contrast can be obtained, and the accuracy of a detection result can be improved.

In a specific example, the position of the brightfield illumination component 2 can be selectively switched between the first station W1 and the second station W2, and of course, the switching of the position of the brightfield illumination component 2 can be driven by a power component or manually, which is not limited herein. When the bright field lighting component 2 is located at the first station W1, the chief ray of the light outlet of the bright field lighting component 2 strikes the field of view position of the imaging light path of the imaging lens 41 and coincides with the imaging chief ray Z2; when the bright field illumination component 2 is located at the second station W2, the bright field illumination component 2 exits the imaging optical path.

In the above embodiment, the position of the bright field illumination component 2 can be switched between the first station W1 and the second station W2, so that the bright field illumination component 2 can exit the bright field region when not operating, thereby avoiding hindering the operation of the dark field illumination component 3, and the dark field light scattered by the back surface of the wafer is directly emitted into the imaging lens 41, thereby avoiding energy loss.

In one embodiment, the bright field illumination component 2 further includes a light splitter 22 in addition to the light source, the light emitted from the light source can vertically irradiate the object to be measured through a rear portion of the light splitter 22, and the reflected light reflected by the object to be measured is partially transmitted into the imaging lens 41 through the light splitter 22, for example, the light emitted from the light source can be parallel to the back surface of the wafer, and the reflected light is vertically irradiated to the back surface of the wafer through the rear portion of the light splitter 22. The angle formed between the light splitter 22 and the light emitted from the light source may be 45 °. Of course, the included angle formed between the light splitter 22 and the light emitted from the light source may be other angles on the premise of achieving the above-mentioned effects.

The detection device of the present invention further comprises a driving component (not shown in the figure), wherein the driving component is used for driving the object to be detected to move horizontally along a predetermined track; the information acquisition component 4 is provided with at least one imaging light path, each imaging light path corresponds to one view field, and the information acquisition component 4 scans the object to be detected in the translation process of the object to be detected. During the translation process of the wafer, the information acquisition assembly 4 finishes scanning the whole back of the wafer.

As described above, when the wafer is detected by the detection equipment, the mode of moving the wafer 1 in a plane is adopted, and the information acquisition assembly 4 or the bright field illumination component 2 is not moved, so that the mechanism is simple and the imaging quality is high.

Usually, the wafer is sucked or held or supported and positioned by a chuck or a holding member or a supporting member 5 (not shown), so that the driving member drives the wafer 1 to move during the actual operation. The driving component may be any component capable of achieving translation, and may be a driving motor or the like.

In the solutions shown in fig. 3 to 7, the information acquisition component 410 of the detection apparatus has two imaging optical paths, the fields of view corresponding to the imaging optical paths are line fields of view, and the line fields of view are collinear. In one specific example, the drive component is capable of driving the wafer to translate in a first direction and a second direction, wherein the first direction and the second direction are perpendicular to each other. For example, in one specific example, the wafer has a diameter of 300mm, the optical axes of the two imaging optical paths are 150mm apart, and the instantaneous line-of-view field of each optical path is 80mm. The two imaging light paths are arranged side by side, namely the two linear view fields are collinear. The wafer is driven by the driving part to move along the arrow in the figure. The wafer is moved upwards by 300mm from the starting point at the lower end, and the 80mm +80mm field scanning of the wafer can be completed. After scanning once, the scanning is performed to the right side or moved by 75mm, and then moved downwards by 300mm, and the field scanning of 80mm +80mm is completed. After two times of scanning, 4 scanning images can be generated, and all the scanning images on the back of the wafer are obtained after splicing.

Of course, according to the actual application requirement, the field of view corresponding to the imaging optical path may also be in other forms, and is not limited to a line field of view, as long as the detection requirement can be met. In addition, the radius of the wafer, the length of the line field of view are not limited to the above description.

The line view field detection effect is better, and the corresponding equipment structure is simple.

Specifically, the information collecting assembly 4 includes an imaging device unit corresponding to the imaging optical path, that is, one imaging optical path corresponds to one imaging device unit, in the scheme shown in fig. 7, a first imaging optical path corresponds to the first field of view 4A, and a second imaging optical path corresponds to the second field of view 4B, specifically, the first field of view 4A and the second field of view 4B may be approximately equal, the distance between the central optical axes of the two field of view is the length of the two field of view lines, and the total length of the two field of view at least can cover the radius of the wafer, so that the wafer translates once, the scanned areas of the first field of view 13A and the second field of view 13B at least cover half of the wafer, and each part of the wafer can be scanned and detected once the wafer reciprocates back and forth.

It should be noted that the figure only shows an example of a case where the information collecting assembly 4 has two imaging optical paths, and the line view fields corresponding to the two imaging optical paths and the radius of the wafer, it is understood that, in actual setting, the information collecting assembly 4 may also have only one imaging optical path, and the line view field corresponding to the imaging optical path at least covers the radius or the diameter of the wafer, or the information collecting assembly 4 may have three or more imaging optical paths, each imaging optical path corresponds to one line view field, and the scanning of the entire back surface of the wafer is completed after the wafer is translated once or twice or N times.

Each imaging device unit 40 includes an imaging lens 41 and a line scan camera. TDI camera response efficiency is related to the integration order, typically 128 or 256 times that of a single line scan. The utility model discloses a 256-level line scanning camera, corresponding efficiency improves by a wide margin, has compensatied the energy decline that adopts thing side of the body teleaxis lens structure NA (the english is called totally the Numerical Aperture entirely, chinese name Numerical Aperture, for short NA) to reduce and lead to. Finally the utility model discloses a total light efficiency in formation of image light path bright field is 2 times of former scheme, and the total light efficiency in dark field is 4 times of former scheme.

Because the line scanning camera is 256 lines and has certain broadening in scanning dimension, an imaging light path of the imaging lens is more beneficial to being vertical to an object to be measured and being arranged in parallel with a main light path of a light outlet of the illuminating part.

In the above embodiments, the range of the incident angle between the main optical axis of the light outlet of the dark field illumination component 3 and the plane where the object to be measured is located is 70 to 85 °, that is, the included angle between the main optical axis of the dark field illumination component 3 and the wafer is relatively small, and the signal-to-noise ratio of the generated image is higher.

Of course, the image signal-to-noise ratio can also be adjusted by integrating the incident angle and the light source color.

The above description is about the light source assembly and the detecting device having the light source assembly provided by the present invention. The principles and embodiments of the present invention have been explained herein using specific examples, and the above descriptions of the embodiments are only used to help understand the method and its core ideas of the present invention. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, the present invention can be further modified and modified, and such modifications and modifications also fall within the protection scope of the appended claims.

Claims (10)

1. The detection equipment is characterized by comprising a bright field illumination component and an information acquisition component, wherein the bright field illumination component is used for irradiating an object to be detected, and the information acquisition component is used for acquiring and processing reflected light of the object to be detected; the information acquisition component is provided with an imaging lens of an object space telecentric structure, and when the bright field illumination component is in a working state, an imaging light path of the imaging lens is perpendicular to a surface to be detected of the object to be detected, and the imaging light path of the imaging lens is parallel to a main light path of a light outlet of the bright field illumination component.

2. The detection apparatus according to claim 1, wherein the position of the bright field illumination component is selectively switchable between a first station and a second station, when the bright field illumination component is located at the first station, a chief ray of the light outlet of the bright field illumination component is incident on a field-of-view position of an imaging optical path of the imaging lens and coincides with an imaging chief ray; when the bright field illumination component is positioned at the second station, the bright field illumination component exits the imaging light path.

3. The detecting apparatus according to claim 2, wherein the bright field illuminating component includes a light source and a light splitting sheet, a rear portion of the light emitted from the light source can vertically irradiate the object to be detected through the light splitting sheet, a portion of the reflected light reflected by the object to be detected is transmitted through the light splitting sheet to enter the imaging lens, and an included angle formed between the light splitting sheet and the light emitted from the light source is 45 °.

4. The inspection apparatus according to claim 1, further comprising a dark field illumination component having an incident angle between a main optical axis of a light outlet of the dark field illumination component and the surface to be inspected of the object ranging from 70 to 85 °.

5. The inspection apparatus of claim 4, wherein the light source of the bright field illumination component or/and the dark field illumination component comprises a monochromatic light source, or a RGB three-color light source, or a RGBW four-color light source, and the light source color of the bright field illumination component or/and the dark field illumination component is selected according to the signal-to-noise ratio of the target image.

6. The detection apparatus according to any one of claims 2 to 5, further comprising a driving member configured to drive the object to be detected to translate along a predetermined trajectory; the information acquisition assembly is provided with at least one imaging light path, each imaging light path corresponds to a view field, and the information acquisition assembly is configured to scan the object to be detected in the translation process of the object to be detected.

7. The apparatus according to claim 6, wherein the object to be measured is a wafer, and the driving unit is capable of driving the wafer to translate along a first direction and a second direction, wherein the first direction and the second direction are perpendicular to each other.

8. The detection apparatus according to claim 7, wherein the information acquisition assembly has at least two imaging optical paths, the fields of view corresponding to the imaging optical paths are linear fields of view, and each of the linear fields of view are collinear.

9. The apparatus according to claim 7, wherein the information acquisition assembly comprises imaging apparatus units corresponding to the imaging optical path, each of the imaging apparatus units comprising the imaging lens and a line scan camera.

10. The detection apparatus according to any one of claims 7 to 9, wherein the information acquisition component has two imaging optical paths, and a coverage length of two line fields corresponding to the two imaging optical paths is greater than or equal to a radius of the wafer.

Images