CN118192045A - Compact highlight collimation lighting device and method for dark field imaging - Google Patents
Compact highlight collimation lighting device and method for dark field imaging Download PDFInfo
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- CN118192045A CN118192045A CN202410426903.XA CN202410426903A CN118192045A CN 118192045 A CN118192045 A CN 118192045A CN 202410426903 A CN202410426903 A CN 202410426903A CN 118192045 A CN118192045 A CN 118192045A
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- 238000003384 imaging method Methods 0.000 title claims abstract description 20
- 238000000034 method Methods 0.000 title claims abstract description 8
- 238000005286 illumination Methods 0.000 claims abstract description 38
- 239000011324 bead Substances 0.000 claims description 4
- 230000000694 effects Effects 0.000 abstract description 2
- 230000007547 defect Effects 0.000 description 6
- 238000001514 detection method Methods 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 4
- 235000012431 wafers Nutrition 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000000877 morphologic effect Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
- G02B13/006—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element at least one element being a compound optical element, e.g. cemented elements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V14/00—Controlling the distribution of the light emitted by adjustment of elements
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/02—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the intensity of light
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0012—Optical design, e.g. procedures, algorithms, optimisation routines
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/30—Collimators
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
- F21Y2115/00—Light-generating elements of semiconductor light sources
- F21Y2115/10—Light-emitting diodes [LED]
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Abstract
The invention discloses a compact highlight collimation lighting device and method for dark field imaging. The light emitted by the illumination light source is captured by the plano-convex lens and enters the system by the illumination light source at a certain space angle alpha, so that the edge light beam of the light source is incident into the range of the double-cemented lens, an aperture diaphragm is arranged behind the plano-convex lens, and the light propagates to the surface of the double-cemented lens through the aperture diaphragm. And then projected to the target surface through the double cemented lens. The collimation of the emergent main light beam is ensured by the whole light path system, and the plano-convex lens and the double-cemented lens form a collimation system, so that the light rays within the space opening angle alpha range emitted by the illumination light source are emergent in parallel after passing through the system. The device can optimize the gathering effect of the light beam under the inclined illumination of the light source by adjusting the aperture size of the aperture diaphragm, so that the light spot brightness is improved. The whole light path design structure is simple and clear, the arrangement structure between the lenses is compact, the whole system is small in size, and the space is saved.
Description
Technical Field
The invention relates to the technical field of semiconductor detection, in particular to a compact highlight collimation lighting device and method for dark field imaging.
Background
Defect inspection of semiconductor wafers refers to the process of inspecting the wafer surface during semiconductor manufacturing to determine if any visible flaws, damage or undesirable features are present. Such defects may include, but are not limited to, scratches, blemishes, cracks, or other morphological irregularities. By performing the appearance defect detection, the manufacturer can find and eliminate problems that may cause malfunction of the apparatus or degradation of performance early, thereby ensuring quality and reliability of the final product.
Bright field illumination and dark field illumination are two techniques commonly used in defect detection, in which a smooth-surfaced wafer surface appears as a dark background in the field of view, while tiny particles, scratches or patterns on the wafer reflect or scatter some light in different directions, so that the particles, scratches or patterns appear as bright spots, lines or patterns, etc. in the field of view of the dark field system, so dark field illumination needs to be provided. In practical use, when the dark field light source is used for low-angle illumination, the oblique illumination of the light source can lead to uneven distribution of light spots on the target surface. Such uneven distribution may have an impact on the imaging or detection process.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a compact highlight collimation lighting device for dark field imaging. The device can optimize the light beam gathering effect under the inclined irradiation of the light source, so that the light spot brightness is improved.
A compact highlight collimation lighting device for dark field imaging mainly comprises a lighting source 1, a plano-convex lens 2, an aperture diaphragm 3 and a double-cemented lens 4.
The light emitted by the illumination light source 1 is captured by the plano-convex lens 2, and the light with a certain space angle alpha of the illumination light source 1 enters the system, so that the edge light beam of the light source is incident into the range of the double-cemented lens 4, the aperture diaphragm 3 is arranged behind the plano-convex lens 2, and the light propagates to the surface of the double-cemented lens 4 through the aperture diaphragm 3. And then projected to the target surface through the doublet lens 4. The collimation of the emergent main light beam is ensured by the whole light path system, and the plano-convex lens 2 and the double-cemented lens 4 form a collimation system, so that light rays within the space opening angle alpha range emitted by the illumination light source 1 pass through the system and are emergent in parallel. The device can adjust the light spot brightness by adjusting the aperture size of the aperture diaphragm 3, and improve the uniformity of the light spot in an oblique illumination mode.
The invention has the advantages that:
(1) The whole light path design structure is simple and clear, the arrangement structure between the lenses is compact, the whole system is small in size, and the space is saved.
(2) The space angle alpha of the light source receiving device is larger than or equal to 56 degrees, and the utilization rate of the light source capacity is ensured.
(3) The pitch angle coverage range of the compact type high-brightness collimation lighting device is 30-60 degrees, and a wider area can be covered.
Drawings
FIG. 1 is a schematic diagram of a compact highlighting collimating illumination device for dark field imaging according to the present invention.
Fig. 2 is a schematic view of a state of a light spot on an image plane.
Fig. 3 is a schematic diagram of the relative illumination of the spot in the x-field direction and the y-field direction.
Fig. 4 is a light path lens data table.
Detailed Description
For oblique illumination, when the incident angle is changed, the central position of the light spot is changed, the energy distribution of the light spot is changed, and the non-uniformity of the light spot is increased. The increased spot non-uniformity may result in some areas receiving stronger light and other areas being weaker, which may result in errors or missed detection in semiconductor chip inspection. Uneven spot distribution may prevent certain fine defects or features from being accurately detected, and the production efficiency is reduced.
Improving the collimation of the outgoing light can help to improve the uniformity of the illuminance of the light spot at the time of oblique incidence. After the light is collimated, the propagation direction of the light is more concentrated and consistent, so that the scattering and deviation of the light are reduced, and the illuminance distribution of the light spot on the target surface is brighter.
Referring to fig. 1, a compact highlighting and collimating illumination device for dark field imaging comprises: the device comprises an illumination light source 1, a plano-convex lens 2, an aperture diaphragm 3 and a double-cemented lens 4, wherein the illumination light source, the plano-convex lens 2, the aperture diaphragm 3 and the double-cemented lens 4 are arranged in sequence from left to right, and a measured object surface 5 is positioned on the right side of the double-cemented lens 4. The specific lighting implementation steps are as follows:
Step one: when the device works, the illumination light source 1 emits light, the plano-convex lens 2 captures the light with a certain space angle alpha of the illumination light source 1 to enter the system, so that the opening angle of the light is reduced, and the edges of the light beams are gathered;
step two: the light passes through the plano-convex lens 2, irradiates onto the aperture diaphragm 3, and projects the light passing through the diaphragm onto the surface of the double cemented lens 4.
Step three: the light passes through the double-cemented lens 4, the opening angle of the light is further reduced, and the plano-convex lens 2 and the double-cemented lens 4 form a set of collimation system, so that the illumination light source 1 emits the light with the opening angle, and the emergent light beam is more uniform light in the working distance and irradiates on the target surface 5.
Further, the higher the capturing capability of the light path to the light source space angle is, the higher the light source energy utilization rate is, and when the 2mm multiplied by 2mmLED patch or LED lamp beads are used, the light source space angle alpha received by the device is more than or equal to 56 degrees, so that the light source capacity utilization rate is ensured. And meanwhile, in order to balance the collimation of the emergent light beam and the uniformity of the light spot illumination, the aperture diaphragm is adjusted by using a variable aperture.
The compact high-brightness collimation lighting device for dark field imaging has a pitch angle coverage range of 30-60 degrees, and a larger pitch angle range means that the lighting device can have a wider moving range in the vertical direction, so that a wider area can be covered. As the pitch angle range of the lighting device increases, the angular range over which it can be adjusted up or down increases accordingly, enabling the light to illuminate higher or lower areas deeper.
The simulation software Zemax is used for simulating the illumination light path, and the figure 2 is the state of the light spot on the image surface during simulation, so that the light distribution in the light spot is uniform, and the light spot has uniform size. The spot size is about 27 x 54mm, and the positioning and alignment requirements of the optical system by the dark field light source with a large spot size are relatively relaxed.
Fig. 3 shows the relative illuminance of the light spot in the x-view field direction and the y-view field direction, the relative illuminance of the whole view field is close to 1 in the x-view field direction, the relative illuminance of the whole view field is distributed above 0.8 in the y-view field direction, and the overall illuminance of the light spot is uniform.
Fig. 4 is a table of optical path lens data including distances between devices, lens materials, lens dimensions, and lens radius of curvature. The optimal distance between the illumination light source 1 and the plano-convex lens 2 is 9.927mm, the plano-convex lens 2 is closely connected with the aperture diaphragm 3, the optimal distance between the aperture diaphragm 3 and the double-cemented lens 4 is 25mm, and the optimal distance between the double-cemented lens 4 and the target surface 5 is 110mm.
The total length of the emergent surface from the illumination light source 1 to the double-cemented lens 4 is 53.167mm, the total length of the light path is short, the structure is compact, the double-cemented lens is suitable for being used in a limited space, the lamp light can be positioned more conveniently, and the flexibility is high.
The illumination source 1 is preferably a green LED bead or LED patch with a size of less than 2mm by 2mm and a divergence angle of greater than 56 degrees.
The plano-convex lens 2, the aperture diaphragm 3 and the double-cemented lens 4 are preferably sized to be 25.4mm in diameter.
The focal length of the plano-convex lens 2 is preferably 25mm, and the focal length of the double-cemented lens 4 is preferably 100mm.
Claims (10)
1. The compact highlight collimation lighting device for dark field imaging is characterized by comprising an illumination light source (1), a plano-convex lens (2), an aperture diaphragm (3) and a double-cemented lens (4);
the light emitted by the illumination light source (1) is captured by the plano-convex lens (2) and enters the system by a certain space angle alpha of the illumination light source (1), so that the edge light beam of the light source is incident into the range of the double-cemented lens (4), an aperture diaphragm (3) is arranged behind the plano-convex lens (2), and the light propagates to the surface of the double-cemented lens (4) through the aperture diaphragm (3); then the light is projected to the target surface through a double-cemented lens (4); the collimation of the emergent main light beam is ensured by the whole light path system, and the plano-convex lens (2) and the double-cemented lens (4) form a collimation system, so that the light rays within the space opening angle alpha range emitted by the illumination light source (1) are emergent in parallel after passing through the system; the device adjusts the spot brightness by adjusting the aperture size of the aperture diaphragm (3) and improves the uniformity of the spot in an oblique illumination mode.
2. The compact highlight collimation lighting device for dark field imaging, according to claim 1, is characterized in that when the device uses a 2mm multiplied by 2mmLED patch or an LED lamp bead, the receiving light source space angle alpha is more than or equal to 56 degrees, and the light source capacity utilization rate is ensured.
3. A compact highlight collimation lighting device for dark field imaging as recited in claim 1, characterised in that the pitch coverage of the device is 30 ° to 60 °.
4. The compact highlight collimation lighting device for dark field imaging according to claim 1, wherein the light spot formed by the device is approximately 1 in the x-view field direction, the relative illumination of the whole view field is distributed above 0.8 in the y-view field direction, and the overall illumination of the light spot is uniform.
5. A compact highlight collimation lighting device for dark field imaging according to claim 1, characterized in that the optimal distance between the lighting source (1) and the plano-convex lens (2) is 9.927mm, the plano-convex lens (2) is closely connected with the aperture stop (3), the optimal distance between the aperture stop (3) and the double-cemented lens (4) is 25mm, and the optimal distance between the double-cemented lens (4) and the target surface 5 is 110mm.
6. The compact highlighting and collimating lighting device for dark field imaging according to claim 1, wherein the total length of the outgoing surface from the lighting source (1) to the double-cemented lens (4) is 53.167mm, the total length of the light path is short, the structure is compact, and the lighting device is suitable for being used in a limited space.
7. A compact highlighting and collimating lighting device for dark field imaging according to claim 1, wherein said lighting source (1) is a green LED bead or LED patch having a size smaller than 2mm x 2mm and a divergence angle larger than 56 °.
8. A compact highlight collimating lighting device for dark field imaging according to claim 1, characterized in that the dimensions of the plano-convex lens (2), aperture stop (3), double cemented lens (4) are 25.4mm in diameter.
9. A compact highlight collimation lighting device for dark field imaging according to claim 1, characterized in that the focal length of the plano-convex lens (2) is chosen to be 25mm and the focal length of the doublet lens (4) is chosen to be 100mm.
10. The implementation method of the compact highlight collimation lighting device for dark field imaging is characterized in that an illumination light source (1), a plano-convex lens (2), an aperture diaphragm (3) and a double-cemented lens (4) are sequentially arranged from left to right, the surface 5 of a measured object is positioned on the right side of the double-cemented lens (4), and specific lighting implementation steps are as follows:
step one: when the device works, the illumination light source (1) emits light, the plano-convex lens (2) captures the light with a certain space angle alpha of the illumination light source (1) to enter the system, so that the opening angle of the light is reduced, and the edges of the light beams are gathered;
Step two: the light passes through the plano-convex lens (2), irradiates onto the aperture diaphragm (3), and projects the light passing through the diaphragm onto the surface of the double-cemented lens (4);
Step three: the light passes through the double-cemented lens (4), the light opening angle is further reduced, and the plano-convex lens (2) and the double-cemented lens (4) form a set of collimation system, so that the illumination light source (1) emits light with the opening angle, and the emitted light beam is more uniform light within the working distance and irradiates on the target surface (5).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410426903.XA CN118192045A (en) | 2024-04-10 | 2024-04-10 | Compact highlight collimation lighting device and method for dark field imaging |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410426903.XA CN118192045A (en) | 2024-04-10 | 2024-04-10 | Compact highlight collimation lighting device and method for dark field imaging |
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| Publication Number | Publication Date |
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| CN118192045A true CN118192045A (en) | 2024-06-14 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202410426903.XA Pending CN118192045A (en) | 2024-04-10 | 2024-04-10 | Compact highlight collimation lighting device and method for dark field imaging |
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| Country | Link |
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| CN (1) | CN118192045A (en) |
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- 2024-04-10 CN CN202410426903.XA patent/CN118192045A/en active Pending
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