TWI728883B - lighting device - Google Patents

Abstract

The lighting equipment of the present invention is used to provide lighting to the lighting area, and the lighting equipment includes at least two lighting devices. At least two lighting devices are arranged around the lighting area and face each other. Each of the at least two illuminating devices is used to vertically converge a plurality of collimated light beams arranged horizontally into parallel light and then focus horizontally into illuminating light to illuminate the illuminated area.

Description

lighting device

The present invention relates to a visual inspection or scanning system, in particular to the lighting equipment of the visual inspection or scanning system.

With the improvement of semiconductor technology, the structure, size, or circuit of semiconductor materials (such as wafers) are becoming more and more refined, and inspections at various stages of the process have become more and more important. Inspection is not only the inspection of semiconductor materials, but also includes the inspection of semiconductor materials. The material or device used, such as a photomask.

The currently known dark area inspection technology is to project the illumination light (projection) on the semiconductor material or photomask, and then use the imaging device to capture the corresponding image. This technology allows dust or foreign objects on the semiconductor material or photomask to be captured. It is bright in the image, and is found.

At present, illuminating light usually uses a high-intensity light source to illuminate the mask. The reflectivity of the pattern formed by the conductive path on the mask is better than the reflectivity of dust or foreign objects. At present, when the illuminating light illuminates the inspected area of the mask , The small dust or foreign objects and patterns in the inspected area will be illuminated, but because the reflectance of the pattern is higher than that of the small dust or foreign objects, the reflected light intensity of the pattern will be greater than that of the small dust or foreign objects. The intensity of the reflected light of foreign objects is not conducive to image acquisition and inspection operations.

In order to avoid the above-mentioned problems caused by the single light source, the current illumination light is also composed of laser beams arranged in a ring, as shown in Figure 6, which is through eight lasers arranged in a ring. The light receiving angle diagram of the beam projected on the object, it can be found that the laser beam is a roughly collimated beam with a single angle, that is to say, the projection angle of the laser beam can produce high-intensity illumination. The difference between the laser beam and the laser beam There is almost no illuminating light in the interval between. Although this lighting method can increase the light receiving angle of the inspected area, it is still not enough to evenly distribute the illuminating light in the range of 360 degrees. Therefore, when the imaging device is shooting, the intensity of the reflected light of the pattern in the inspected area is still The intensity of the reflected light from small dust or foreign objects may occur at a specific angle, so it is not conducive to imaging and inspection operations.

The lighting device of the present invention can provide more abundant angles and high-intensity lighting to clearly illuminate foreign objects or defects, and clearly identify the location and size of the foreign objects or defects.

In order to achieve the above object, the lighting equipment of the present invention is used to provide lighting to the lighting area, and the lighting equipment includes at least two lighting devices. At least two lighting devices are arranged around the lighting area and face each other. Each of the at least two illuminating devices is used to vertically converge a plurality of collimated light beams arranged horizontally into parallel light and then focus horizontally into illuminating light to illuminate the illuminated area.

In this way, the illumination device of the present invention can provide multi-angle illumination through the illumination light focused by a plurality of collimated beams, and can provide high-illuminance illumination to the illumination area.

In order to achieve the above object, the lighting device of the present invention is used to provide lighting to the lighting area. The lighting equipment includes a plurality of lighting devices. A plurality of lighting devices are arranged around the lighting area. Each of the multiple illuminating devices is used to vertically converge multiple collimated light beams arranged horizontally into parallel light and then focus horizontally into illuminating light to illuminate the illuminated area.

In this way, the illumination device of the present invention can provide more angle and brightness illumination through multiple collimated light beams, and provide wider angle illumination through the illumination device surrounding the illumination area.

The detailed structure, composition, characteristics, operation, or use of the lighting equipment provided by the present invention will be described in the detailed description of the subsequent implementation manners. However, those with ordinary knowledge in the field of creation should be able to understand that these detailed descriptions and specific embodiments listed in the implementation of this creation are only used to illustrate the creation, and are not intended to limit the scope of the patent application of the present invention.

100: Vision scanning system

11, 51: lighting equipment

13: Acquisition equipment

131: The first camera

132,134: Filter

133: second camera

135: Spectroscope

137, 59: Acquisition area

15,55: lighting area

151: Reflected light

17,19,53: lighting installation

171: Light-emitting unit

172: Light-emitting element

1721: divergent light

173: Micro lens array

174: Micro lens

1741: collimated beam

175: The first lens

1751: Parallel Light

176: second lens

177, 57: Illumination light

300: Mask

31: glass

32: pattern layer

33: Frame

35: Membrane

Fig. 1 is a schematic diagram of the illumination device of the present invention applied to a visual scanning system to inspect an object.

Fig. 2 is a schematic top view of the optical structure and illuminating light of one of the illuminating devices of the illuminating device in Fig. 1.

Fig. 3 is a side view of the optical structure and illuminating light of one of the illuminating devices of the illuminating device in Fig. 1.

4 is a schematic diagram of the illumination area and the annular arrangement of the illumination devices viewed from the imaging device of the vision scanning system in FIG. 1.

FIG. 5 is a diagram showing the relationship between the light receiving angle and light intensity of the object when the lighting device in FIG. 4 is used to illuminate an object.

Fig. 6 is a diagram showing the relationship between the angle of light received by an object and the light intensity measured by a ring-shaped laser beam.

Hereinafter, the corresponding preferred embodiments are listed in conjunction with the drawings to illustrate the components and effects of the lighting device of the present invention. However, the components, size, appearance, and lighting range of the lighting equipment in the various drawings are only used to illustrate the technical features of the present invention, but not to limit the present invention.

As shown in Figure 1, the lighting equipment of the present invention is often applied to a visual scanning system 100 of a specific manufacturing process. The visual scanning system 100 takes a part of the image of the inspected surface of the inspected object and inspects the corresponding image through known image processing technology. State of the inspected surface, and mark information on the inspected surface, for example, the location of dust, dust, dirt or defects on the inspected surface.

Inspection environment for objects to be inspected, such as glass, wafers, and photomasks. In the description of the following embodiments, the object to be inspected takes the photomask 300 as an example. The mask 300 includes a glass 31, a frame 33 and a film 35, and the surface of the glass 31 includes a pattern layer 32. The frame 33 is connected to the glass 31 and frames the pattern layer 32. The film 35 is connected to the frame 33 to prevent foreign matter (such as dust) from adhering to the pattern layer 32. The inspected surface is the pattern layer 32.

The visual scanning system 100 includes a lighting device 11 and an image capturing device 13. The lighting device 11 is used to illuminate the lighting area 15 of the pattern layer 32, and the lighting area 15 is a partial area of the pattern layer 32. The lighting equipment 11 includes two lighting devices 17 and 19. The two lighting devices 17 and 19 are arranged around the lighting area 15 and face each other. The image capturing device 13 is used to capture the image of the pattern layer 32 in the image capturing area 137. The image capturing area 137 is the range where the image capturing device 13 observes the pattern layer 32, as shown in the figure by two dotted lines. The range of the illumination area 15 is roughly smaller than the image capturing area 137. The imaging device 13 captures an image of the illumination area 15 and includes a first camera 131, a second camera 133 and a beam splitter 135.

In this embodiment, the illuminating device 17 produces blue visible light illumination, and the illuminating device 19 produces green visible light illumination. The first camera 131 and the second camera 133 of the imaging device 13 have filters 132 and 134, respectively. The filter 132 of the first camera 131 filters out blue visible light to receive green visible light, and the filter 134 of the second camera 133 It filters out the green visible light to receive the blue visible light. In other embodiments, the illuminating devices 17 and 19 may also be visible or invisible light of other colors or all the same colors, so the selection of the color of the illuminating light of the illuminating devices 17 and 19 is not limited to that described in this embodiment.

In this embodiment, the reflected light 151 illuminated in the illumination area 15 enters the imaging device 13, and enters the first camera 131 and the second camera 133 through the beam splitter 135 to form corresponding images, and the images pass through the known The image processing technology is used to identify the state of the pattern layer.

Because the imaging area or the illumination area 15 is smaller than the pattern layer 32, in this embodiment, the size of the illumination area 15 is approximately 10mm*10mm. Therefore, in order to inspect the entire pattern layer 32, the photomask 300 and the vision scanning system 100 will face each other. Move, for example, move the photomask 300 to allow the visual scanning system 100 to inspect the entire pattern layer 32, or move the visual scanning system 100 to sequentially inspect the entire pattern layer 32 of the photomask 300.

As shown in Figures 2 and 3, the lighting devices 17 and 19 have the same structure. Then, the lighting device numbered 17 is taken as an example. The lighting device 17 includes a light-emitting unit 171, a micro lens array 173, a first lens 175, and a second lens. 176. The light emitting unit 171 includes a plurality of light emitting elements 172 to generate a plurality of divergent lights 1721, and the light emitting elements 172 may be light emitting diodes (LEDs). The light emitting elements 172 are arranged at intervals along a horizontal line to provide light sources arranged horizontally at multiple angles. The microlens array 173 is located between the light-emitting unit 171 and the condenser lens 175, and includes a plurality of microlenses 174. The microlenses 174 are arranged along the same horizontal line as the light-emitting elements 172. The arrangement of the light-emitting elements 172 and the microlenses 174 is the same as that of the light-emitting elements 172. The horizontal lines are arranged in parallel. The divergent light 1721 generated by the light-emitting element 172 passes through the microlens 174 one-to-one to output a horizontally aligned and substantially collimated light beam 1741, and the collimated light beam 1741 is arranged along a horizontal line. The light emitting element 172 is a one-to-one alignment microlens 174, and the microlens 174 may be cylindrical. Among them, the horizontally aligned collimated light beam 1741 is roughly a linear light source. The first lens 175 includes a spherical surface. The collimated light beam 1741 passes through the first lens 175 to vertically converge and output the parallel light 1751. The vertical converging is to restrict the highest and lowest projection range of the parallel light 1751 through the first lens 175, so that the parallel light 1751 converges Illumination with a linear light source at a specific height. The second lens 176 faces the first lens 175, and is used to allow the parallel light 1751 to pass through and focus horizontally to output the illuminating light 177. The illuminating light 177 finally Focusing into a point light source, in this way, the illuminating light 177 generated by the illuminating devices 17 and 19 can achieve the purpose of multi-angle confocal and increased brightness, that is, it has the characteristics of high brightness and rich light receiving angle.

In this way, the illuminating devices 17 and 19 of the present invention can provide multi-angle and high-brightness illumination by passing the horizontally aligned collimated light beams 1741 and vertically converging them into parallel light 1751 and then focusing horizontally into the illuminating light 175.

As shown in Fig. 4, Fig. 4 is a schematic diagram of the illumination area viewed by the imaging device. The lighting equipment 51 includes eight lighting devices 53. The eight lighting devices 53 are arranged around the lighting area 55 and surrounded to form 360-degree lighting. The lighting light 57 of the eight lighting devices 53 is irradiated in the lighting area 55 to provide The illumination area 55 has multi-angle and high-brightness (light intensity) illumination, and the composition and application of each illuminating device 53 are the same as the aforementioned illuminating device 17 and will not be repeated here. The illumination area 55 is in the image capturing area 59, and the image capturing area 59 is substantially circular. In this way, the illuminating device 51 can provide illumination that substantially covers 360 degrees of light and has the characteristics of high brightness.

As shown in Fig. 5, Fig. 5 is a measurement diagram of the light intensity of the light received by the object in Fig. 4. Since the lighting device of the present invention converts the linear light source formed by the multi-angle light source into the focused lighting light, it can be understood from FIG. 5 that each lighting device can provide a wider angle of lighting light, so that the light receiving angle of the object is more abundant. In addition, the focused illuminating light output by each illuminating device can output the light intensity of the light-emitting element, thereby effectively increasing the light intensity of the light received on the surface of the object.

When performing dark area inspection, the illuminating light of the illuminating device of the present invention can prevent the pattern of the mask from producing strong reflected light, and can increase the reflected light intensity of dust or foreign objects, and is more suitable for distinguishing the position and size of dust or foreign objects Etc., in order to improve the recognition ability of the visual scanning system.

Finally, it is emphasized again that the constituent elements disclosed in the previously disclosed embodiments of the present invention are only examples and are not used to limit the scope of the case. The substitution or change of other equivalent elements shall also be subject to the scope of the patent application of this case. Covered.

100: Vision scanning system

11: lighting equipment

13: Acquisition equipment

131: The first camera

132,134: Filter

133: second camera

135: Spectroscope

137: Acquisition area

15: lighting area

151: Reflected light

17,19: Lighting installation

300: Mask

31: glass

32: pattern layer

33: Frame

35: Membrane

Claims (9)

A lighting device for providing lighting to a lighting area, comprising: at least two lighting devices arranged around the lighting area and facing each other, and each of the at least two lighting devices is used for horizontally arranging a plurality of lighting devices. A collimated light beam is vertically converged into a parallel light and then horizontally focused into an illuminating light to illuminate the illuminating area, and the illuminating light is a point light source. The lighting device according to claim 1, wherein the parallel light is a linear light source. The lighting device according to claim 1, wherein each of the at least two lighting devices includes a light-emitting unit, a microlens array, a first lens, and a second lens, and the light-emitting unit includes a plurality of light-emitting elements, To generate a plurality of divergent lights, the microlens array is located between the light emitting unit and the first lens, and includes a plurality of microlenses, and the plurality of divergent lights pass through the plurality of microlenses one by one to output the plurality of collimated lights. A straight light beam, the plurality of collimated light beams pass through the first lens to vertically converge and output the parallel light, and the second lens faces the first lens and is used for allowing the parallel light to pass through and focus horizontally to output the illuminating light. The lighting device according to claim 3, wherein the arrangement of the plurality of light-emitting elements and the plurality of microlenses is a parallel arrangement. The lighting device according to claim 1, wherein the lighting light of the at least two lighting devices includes a blue visible light and a green visible light. A lighting device used to illuminate a lighting area, including: A plurality of illuminating devices are arranged around the illuminating area, and each of the plurality of illuminating devices is used to vertically converge a plurality of collimated light beams arranged horizontally into a parallel light and then focus horizontally into an illuminating light to illuminate the illumination Area, the illuminating light is a point light source. The lighting device according to claim 6, wherein the parallel light is a line light source. The lighting device according to claim 6, wherein each of the plurality of lighting devices includes a light-emitting unit, a microlens array, a first lens, and a second lens, and the light-emitting unit includes a plurality of light-emitting elements to Generate a plurality of divergent lights, the micro lens array is located between the light-emitting unit and the first lens, and includes a plurality of micro lenses, the plurality of divergent lights pass through the plurality of micro lenses one-to-one to output the plurality of collimated lights The collimated light beams pass through the first lens to vertically converge and output the parallel light. The second lens faces the first lens and is used for allowing the parallel light to pass through and converge horizontally to output the illuminating light. The lighting device according to claim 8, wherein the arrangement of the plurality of light-emitting elements and the plurality of microlenses is a parallel arrangement.

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