TWI814365B - Optical inspection system based on laser light source and laser optical system - Google Patents

Abstract

An optical inspection system based on laser light source including at least one laser light source device, at least one sensing device, and an image inspection device is provided. By an illumination optical path, the laser light source device provides a laser to a target, so that the target generates a fluorescence. By the imaging optical path, the sensing device receives the fluorescence generated from the target to generate a fluorescent image. The image inspection device is connected to the sensing device, and configured to receive and analyze the fluorescent image to obtain a fluorescent inspection result. A laser optical system is also provided.

Description

Optical detection system and laser optical system based on laser light source

The invention relates to an optical detection system and a laser optical system based on a laser light source.

With the development of the automation industry, Automated Optical Inspection (AOI) has replaced manual inspection and is widely used in industrial production. Automatic optical inspection usually uses a camera to obtain the surface image of the target object, and then uses image processing technology to analyze defects such as abnormal objects or image anomalies. Fluorescence detection uses organic matter in the target to generate fluorescence, which can provide higher detection quality, so it has become one of the options for automatic optical detection. For example, a transparent colloid can clearly highlight its appearance through the fluorescence produced when the colloid is irradiated with excitation light.

In addition, in the use of light sources for automatic optical detection, since laser light sources can provide light with a wavelength range close to a single wavelength, the energy conversion efficiency generated by fluorescence is higher, so laser light sources can be used as a better light source for fluorescence detection. However, due to the good coherence of laser light, laser light is prone to produce speckle patterns (i.e., uneven light and dark patterns) on the target due to interference phenomena during transmission. Therefore, the use of laser light sources results in poor image quality, which in turn affects the detection results after image analysis.

One object of the present invention is to provide an optical detection system based on a laser light source.

Another object of the present invention is to provide a laser optical system that can effectively reduce the spot phenomenon of excitation light irradiating on the target, so the imaging quality is better and the reliability of the detection results is improved.

An embodiment of the present invention provides an optical detection system based on a laser light source, which includes at least one laser light source device, at least one sensing device and an image detection device. Through the illumination light path, the laser light source device provides laser light to the target object, causing the target object to generate fluorescence. Through the imaging light path, the sensing device receives fluorescence generated from the target object to generate a fluorescence image. The image detection device is connected to the sensing device for receiving and analyzing fluorescence images to obtain fluorescence detection results.

An embodiment of the present invention provides an optical detection system based on a laser light source, which includes an objective lens, a laser light source device, a light source filter module, a line scan camera, a sensing device filter module, and an image detection device. The objective lens images the target object through the imaging optical path. Through the illumination light path, the laser light source device provides laser light to the target object through the objective lens, causing the target object to produce fluorescence. Through the illumination light path, the light source filter module allows the excitation light wavelength component of the laser light to pass to the target object. Through the imaging optical path, the line scan camera receives fluorescence from the target object through the objective lens to obtain a fluorescence image. Through the imaging light path, the filter module of the sensing device passes the wavelength components of the fluorescence, thereby generating a fluorescence image. The image detection device is connected to the line scan camera, receives and analyzes the fluorescence image to obtain the fluorescence detection result.

An embodiment of the present invention provides a laser optical system, including a light-emitting unit, a homogenizing optical fiber and a high-frequency oscillator. Through the illumination light path, the light-emitting unit provides laser light to the target object, so that the laser light generates an image of the target object on the sensing device. Through the illumination optical path, the homogenizing optical fiber receives and transmits the laser light. The high-frequency oscillator is installed at the light input end of the homogenizing fiber and vibrates the homogenizing fiber to reduce the spot on the target image.

Based on the above, in the optical detection system and the laser optical system according to one embodiment of the present invention, in addition to using the homogenizing fiber to homogenize the laser light, a high-frequency oscillator is also used to adjust the transmission path of the laser light in the homogenizing fiber. It is not fixed to suppress the interference effect of laser light, further suppressing the light spots on the target image and improving the reliability of the detection results.

Figure 1 is a schematic diagram of an optical detection system according to a first embodiment of the present invention. Please refer to Figure 1. An embodiment of the present invention provides an optical detection system 10 (or a laser optical system) based on a laser light source, which includes at least one laser light source device 110, at least one sensing device 200 and an image detection system. Device 300.

FIG. 2 is a schematic diagram of the laser light source device in FIG. 1 . Please refer to FIGS. 1 and 2 . In this embodiment, the laser light source device 110 includes a light emitting unit 114 , a homogenizing optical fiber 120 and a high-frequency oscillator 130 . The light emitting unit 114 includes a Gaussian distributed laser light source. Through the illumination light path EO, the light-emitting unit 114 is used to provide laser light L to the target object W, so that the laser light L generates an image of the target object on the sensing device 200 . Among them, the laser light L can be red light, green light, blue light, UV light, IR light or other colored light. The target object W includes, but is not limited to, a semiconductor device, a semiconductor wafer, a semiconductor wafer, a circuit board or a display panel.

In this embodiment, the homogenizing optical fiber 120 is connected to the light emitting unit 114 . Via the illumination light path EO, the homogenizing optical fiber 120 receives and transmits the laser light L from the light emitting unit 114 . The high-frequency oscillator 130 is disposed at the light input end 120S1 of the homogenizing optical fiber 120 and vibrates the homogenizing optical fiber 120 to reduce the light spots on the target image. The homogenized optical fiber 120 may be a multi-mode optical fiber (Multi-mode Fiber), an optical fiber roughened at the light input end 120S1 or the light output end 120S2, or an optical fiber spliced by sub-fibers of different diameters. The high-frequency oscillator 130 may be an oscillator made of piezoelectric material, but the present invention is not limited thereto.

Please refer to FIG. 1. In this embodiment, through the imaging optical path IO, the sensing device 200 receives the laser light R reflected from the target object W to generate an image of the target object. Among them, the type of the sensing device 200 may include a line scan camera (Line Scan Camera) and/or an area scan camera (Area Scan Camera). In one embodiment, a line scan camera can be used to perform high-precision inspection, and an area scan camera can be used to perform a re-inspection process, thereby realizing the functions of image inspection and image re-inspection on the same system.

In this embodiment, the image detection device 300 is connected to the sensing device 200 and is used to receive and analyze target object images to obtain image detection results. The image detection device 300 is, for example, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a programmable processing device, a programmable logic device ( programmable logic device (PLD) or other similar devices or combinations of these devices, the present invention is not limited. In addition, in one embodiment, each function of the image detection device 300 can be implemented as a plurality of program codes. These program codes will be stored in a memory, and the image detection device 300 will execute these program codes. Alternatively, in one embodiment, each function of the image detection device 300 may be implemented as one or more circuits. The present invention is not limited to using software or hardware to implement each function of the image detection device 300.

In one embodiment, the above-mentioned reflected laser light R may be fluorescent light (fluorescent light F as shown in FIG. 3A ). That is to say, the laser light L is irradiated onto the target object W, causing the target object W to generate fluorescence, and the sensing device 200 receives the fluorescence generated from the target object W to generate a fluorescence image. The image detection device 300 is connected to the sensing device 200 for receiving and analyzing fluorescence images to obtain fluorescence detection results. The target object W may also include, but is not limited to, for example, a semiconductor device, a semiconductor wafer, a semiconductor wafer, a circuit board, a display panel or other objects containing organic matter. For example, the laser light L can be ultraviolet light or blue light, and the target object W can convert the ultraviolet light (laser light L) into blue light (fluorescent light F) or can convert the blue light (laser light L) into green light (fluorescent light). Light F), but the present invention is not limited to this.

In this embodiment, the optical detection system 10 further includes a beam splitter 140 . Via the illumination optical path EO, the spectroscope 140 guides the laser light L from the laser light source device 110 to the target W, and via the imaging optical path IO, guides the reflected laser light R (or fluorescence) from the target W to the sensing device 200 .

Based on the above, in the optical detection system 10 according to an embodiment of the present invention, in addition to using the homogenizing fiber 120 to homogenize the laser light L, a high-frequency oscillator 130 is also used to transmit the laser light L in the homogenizing fiber 120 The path is not fixed to suppress the interference effect of the laser light L, further suppressing the light spots on the target image. In one embodiment, the laser light source device 110 includes a Gaussian distributed laser light source 112. Therefore, the laser light L forms a flat-top light pattern with uniform energy after passing through the homogenizing fiber 120. In addition to reducing the influence of light spots, energy loss is also reduced. Can be less than 10%.

Figure 3A is a schematic diagram of an optical detection system according to a second embodiment of the present invention. Please refer to FIG. 3A . The optical detection system 20 based on the laser light source of this embodiment is similar to the optical detection system 10 of FIG. 1 , with the following differences. In this embodiment, the optical detection system 20 further includes a light source filter module 150 and a sensing device filter module 210 . The light source filter module 150 is disposed between the laser light source device 110 and the beam splitter 140 . Through the illumination light path IO, the light source filter module 150 allows the excitation light wavelength component of the laser light L to pass onto the target object W. The sensing device filter module 210 is disposed between the sensing device 200 and the beam splitter 140 . Through the imaging light path IO, the sensing device filter module 210 allows the wavelength component of the fluorescent light F to pass through, thereby generating a fluorescent image.

Figure 3B is a schematic diagram of an objective lens system in Figure 3A. Please refer to FIG. 3A and FIG. 3B. In this embodiment, through the illumination light path EO, the sensing device 200 receives the fluorescence F generated from the target object W through the objective lens system or the fixed focus lens system 160 to generate a fluorescence image. The objective lens system or fixed focus lens system 160 is disposed between the beam splitter 140 and the target object W on the illumination light path EO or the imaging light path IO. Taking FIG. 3B as an example, the objective lens system may include a plurality of objective lenses 162 and a rotating disk 164. Each objective lens 162 has a different objective aperture. The rotating disk 164 carries the objective lenses 162, thereby switching any one of the objective lenses 162 to move to the illumination light path EO or the imaging light path IO.

Based on the above, the advantages of the optical detection system 20 of this embodiment are generally similar to the optical detection system 10 of FIG. 1 , and will not be described again here.

Figure 4 is a schematic diagram of an optical detection system according to a third embodiment of the present invention. Please refer to FIG. 4 . The optical detection system 30 is similar to the optical detection system 20 of FIG. 3A . The main difference is that the laser light source device 110 of the optical detection system 30 includes a plurality of side light sources 116 to illuminate the target object W at different incident angles. , causing the target W to produce fluorescence F. Since the side light source 116 in the optical detection system 30 irradiates the target object W at different incident angles, the light pattern of the laser light L irradiating the target object W is relatively uniform. Moreover, setting up multiple light sources helps to increase the lighting energy, thereby improving the signal-to-noise ratio of fluorescent images, thereby increasing the detection speed. The remaining advantages of the optical detection system 30 are similar to the optical detection system 20 of FIG. 3A and will not be described again here.

Figure 5 is a schematic diagram of an optical detection system according to a fourth embodiment of the present invention. Please refer to Figure 5. The optical detection system 40 is similar to the optical detection system 20 of Figure 3A. The main difference is that the optical detection system 40 based on the laser light source includes an objective lens 162, a laser light source device 110, a light source filter module 150, Line scan camera 200'''', sensing device filter module 210 and image detection device 300. In this embodiment, the objective lens 162 images the target object W via the imaging optical path 10. Through the illumination light path EO, the laser light source device 110 provides the laser light L to the target object W through the objective lens 162, so that the target W generates fluorescence F. Through the imaging optical path 10, the line scan camera 200''' receives the fluorescence F from the target object W through the objective lens 162 to obtain a fluorescence image. The image detection device 300 is connected to the line scan camera 200''', receives and analyzes the fluorescence image to obtain the fluorescence detection result.

In this embodiment, the optical detection system 40 further includes a beam splitter 140 . The spectroscope 140 is disposed between the illumination light path EO and the imaging light path IO, guides the laser light L from the laser light source device 110 to the target object W, and guides the fluorescent light F from the target object W to the line scan camera 200 via the imaging light path IO. '''.

Based on the above, the remaining advantages of the optical detection system 40 of this embodiment are similar to the optical detection system 20 of FIG. 3A and will not be described again here.

To sum up, in the optical detection system and the laser optical system according to one embodiment of the present invention, in addition to using the homogenizing fiber to homogenize the laser light, a high-frequency oscillator is also used to make the laser light in the homogenizing fiber. The transmission path is not fixed to suppress the interference effect of laser light, further suppressing the light spots on the target image. In one embodiment, the laser light source device includes a Gaussian distributed laser light source. Therefore, the laser light forms a flat-top light pattern with uniform energy after passing through the homogenized optical fiber. In addition to reducing the impact of light spots, the energy loss can be less than 10 %.

10, 20, 30, 40: Optical detection system 110:Laser light source device 114:Light-emitting unit 116: Side light source 120: Homogenized optical fiber 120S1: light input end 120S2: light output end 130: High frequency oscillator 140: Beam splitter 150:Light source filter module 160: Objective lens system or fixed focus lens system 162:Objective lens 164: Rotating disk 200: Sensing device 200''': Line scan camera 210: Sensing device filter module 300:Image detection device F: Fluorescence L, R: laser light W: target EO: lighting path IO: imaging optical path

Figure 1 is a schematic diagram of an optical detection system according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of the laser light source device in FIG. 1 . Figure 3A is a schematic diagram of an optical detection system according to a second embodiment of the present invention. Figure 3B is a schematic diagram of an objective lens system in Figure 3A. Figure 4 is a schematic diagram of an optical detection system according to a third embodiment of the present invention. Figure 5 is a schematic diagram of an optical detection system according to a fourth embodiment of the present invention.

10: Optical detection system

110:Laser light source device

140: Beam splitter

200: Sensing device

300:Image detection device

L, R: laser light

W: target

EO: lighting path

IO: imaging optical path

Claims (16)

An optical detection system based on a laser light source, including: at least one laser light source device, providing a laser light to a target object through an illumination light path, so that the target object generates fluorescence; at least one sensing device, through an illumination light path The imaging light path receives the fluorescence generated from the target object to generate a fluorescence image; and an image detection device is connected to the at least one sensing device for receiving and analyzing the fluorescence image to obtain a fluorescence image. Light detection results, wherein the at least one laser light source device includes: a light-emitting unit to provide the laser light; a homogenizing optical fiber connected to the light-emitting unit to receive and transmit the laser light; and a high-frequency oscillator, It is arranged at the light input end of the homogenized optical fiber to vibrate the homogenized optical fiber. The optical detection system based on laser light source as claimed in claim 1, wherein the target object includes a semiconductor device, a semiconductor wafer, a semiconductor chip, a circuit board, a display panel or other objects containing organic matter. The optical detection system based on a laser light source as claimed in claim 1, wherein the laser light source device includes a plurality of side light sources that illuminate the target object at different incident angles to cause the target object to generate fluorescence. The optical detection system based on laser light source as described in claim 1 further includes: A beam splitter guides the laser light from the laser source device to the target object through the illumination light path, and guides the fluorescence from the target object to the sensing device through the imaging light path. The optical detection system based on the laser light source as described in claim 1, wherein the sensing device receives the fluorescence generated from the target object through the illumination light path through an objective lens system or a certain focus lens system to generate the fluorescence light image. The optical detection system based on laser light source as claimed in claim 1, wherein the type of the sensing device includes a line scan camera and/or an area scan camera. The optical detection system based on the laser light source as described in claim 1 further includes: a light source filter module that allows the excitation light wavelength component of the laser light to pass to the target object through the illumination light path; and a sensor A filter module is installed to pass the wavelength component of the fluorescent light through the imaging light path, thereby generating the fluorescent image. The optical detection system based on a laser light source as claimed in claim 1, wherein the light-emitting unit includes a Gaussian distributed laser light source. An optical detection system based on a laser light source, including: an objective lens, which images a target object through an imaging light path; a laser light source device, which provides a laser light to the target object through the objective lens through an illumination light path, so that The target object generates fluorescence; a light source filter module allows the excitation light wavelength component of the laser light to pass to the target object through the illumination light path; A line scanning camera receives the fluorescence from the target object through the objective lens through the imaging light path to obtain a fluorescence image; a sensing device filter module uses the imaging light path to adjust the wavelength of the fluorescence The components pass through to generate the fluorescent image; and an image detection device is connected to the line scan camera to receive and analyze the fluorescent image to obtain a fluorescence detection result, wherein the laser light source device includes: a light-emitting unit , used to provide the laser light; a homogenizing optical fiber, connected to the light-emitting unit, receiving and transmitting the laser light; and a high-frequency oscillator, arranged at the light input end of the homogenizing optical fiber, to vibrate the homogenizing optical fiber . The optical detection system based on a laser light source as claimed in claim 9, wherein the target object includes a semiconductor device, a semiconductor wafer, a semiconductor chip, a circuit board, a display panel or other objects containing organic matter. The optical detection system based on the laser light source as described in claim 9, further comprising: a beam splitter, disposed between the illumination light path and the imaging light path, guiding the laser light from the laser light source device to the target object , and guide the fluorescent light from the target to the line scan camera through the imaging optical path. The optical detection system based on a laser light source as claimed in claim 9, wherein the light-emitting unit includes a Gaussian distributed laser light source. A laser optical system includes: a light-emitting unit that provides a laser light to a target object through an illumination light path, so that the laser light generates a target object image on a sensing device; a homogenizing optical fiber that passes through the The illumination light path receives and transmits the laser light from the light-emitting unit; a high-frequency oscillator is provided at the light input end of the homogenizing optical fiber to vibrate the homogenizing optical fiber to reduce the light spot on the target image. The laser optical system of claim 13, wherein the light-emitting unit includes a Gaussian distributed laser light source. The laser optical system of claim 13, further comprising: the sensing device receives the laser light reflected from the target object through an imaging optical path to generate an image of the target object; and an image detection device , connected to the sensing device, for receiving and analyzing the target image to obtain an image detection result. The laser optical system as claimed in claim 13, further comprising: a beam splitter, which guides the laser light from the light source device to the target object through the illumination light path, and guides the laser light from the target object through the imaging light path. Guide the laser light to the sensing device.

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