TWI714301B - Defect of photoresist chip detection system and method thereof - Google Patents

Abstract

A defect of photoresist chip detection system is provided. The processing unit receives a center wavelength corresponding to a bandwidth range, and determines a central wave length of a tunable beam correspondingly such that the center wavelength of the tunable beam is different from the corresponding center wavelength of the bandwidth range. The tunable wavelength source device emits a tunable beam according to the center wavelength, and the photoresist chip is located on the transmission path of the tunable beam. A second portion of the tunable beam passes through the photoresist chip to form a transmitted beam. An imaging lens is located on the transmission path of the transmitted beam. An image sensor has an image sensing surface, and the transmitted beam is imaged on the image sensing surface to generate a detection image.

Description

Photoresist material defect detection system and method

The invention relates to a detection technology, and more particularly to a photoresist material defect detection system and method.

Due to the influence of temperature, materials, equipment and other factors, the defects of electronic parts are difficult to completely avoid. In order to ensure an increase in yield, defect detection of finished electronic parts is an important part of the manufacturing process. In the prior art, optical methods are often used to detect film thickness unevenness. However, the existing machine can only perform detection by an optical machine with a fixed wavelength, and cannot use an appropriate detection wavelength for different objects to be tested, which makes the detection effect limited.

The invention provides a photoresist material defect detection system and a method thereof, so as to adopt an appropriate detection wavelength according to different photoresist materials to provide more precise detection results.

The photoresist material defect detection system of the present invention is suitable for detecting the photoresist material, and the light in the bandwidth range will pass through the photoresist material. The photoresist material defect detection system has a processing unit, a tunable wavelength light source device, an imaging lens and an image sensor. The processing unit receives the center wavelength corresponding to the bandwidth range, and determines the center wavelength of the adjustable light beam according to the center wavelength data, so that the center wavelength of the adjustable light beam is different from the center wavelength corresponding to the bandwidth range. The tunable wavelength light source device is electrically connected to the processing unit, and emits a tunable light beam according to the center wavelength. The photoresist material is located on the transmission path of the tunable light beam, and the first part of the tunable light beam is absorbed by the photoresist material and the light beam The second part of the photoresist material is penetrated to form a penetrating beam. The imaging lens is located on the transmission path of the penetrating beam. The image sensor is electrically connected to the processing unit and has an image sensing surface. The penetrating light beam passes through the imaging lens and forms images on the image sensing surface to generate a detection image.

The photoresist material defect detection method of the present invention is suitable for detecting the photoresist material, and the light in the frequency bandwidth will pass through the photoresist material. The photoresist material defect detection method has the following steps. Receive the center wavelength corresponding to the bandwidth range; determine the center wavelength of the adjustable beam according to the center wavelength so that the center wavelength of the adjustable beam is different from the corresponding center wavelength of the bandwidth range; and emit the adjustable light beam according to the center wavelength. The adjustable light beam is absorbed by the photoresist material and the color light beam penetrates the photoresist material to form a penetrating beam, and the penetrating beam passes through the imaging lens and is imaged on the image sensing surface to generate a detection image.

Based on the foregoing, the photoresist material defect detection system and method of the present invention can further adjust the center wavelength of the adjustable light beam through the adjustable wavelength light source device, and make the center wavelength of the adjustable light beam different from the corresponding center wavelength of the bandwidth range. Based on this, the tunable wavelength light source device will use an appropriate center wavelength and bandwidth for detection according to different objects to be tested to enhance the detection effect.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

Fig. 1 shows a schematic diagram of a photoresist material defect detection system according to an embodiment of the present invention. Please refer to FIG. 1, in the embodiment of the present invention, the object to be tested is a photoresist material 10. The photoresist material 10 is coated with a photoresist film to absorb or reflect light outside the bandwidth range. In addition, light in the bandwidth range can pass through the photoresist material 10. In other words, the photoresist material 10 can be used to pass light in the bandwidth range. For example, the red photoresist material can absorb red light, for example, the red light with a bandwidth range of 620-750 nm. In addition, the center wavelength corresponding to the bandwidth range is 685 nm. That is to say, the light with a center wavelength of 685 nm has a better effect of penetrating the light resistance film 10, but the present invention does not limit the application of the photoresist film Bandwidth range. It should be noted that although the photoresist material 10 theoretically only allows light in the bandwidth range to pass, it is difficult for the photoresist film to achieve 100% shading rate due to factors such as material and thickness. Therefore, a small part of the light beam falling outside the bandwidth range 620-750 will still penetrate the photoresist material 10. However, in an actual example, the light transmittance outside the bandwidth is about 1% or less. Similarly, a small part of the light beams falling within the bandwidth range cannot penetrate the photoresist material. In particular, light with the same wavelength as the center wavelength penetrates the photoresist material 10 better. If the wavelength of light slowly changes from the center wavelength along the bandwidth range to the boundary of the bandwidth range, the overall trend of the transmittance will decrease.

The photoresist material defect detection system 100 of the present invention is used to detect whether the photoresist film coated on the photoresist material 10 has uneven film thickness. The photoresist material defect detection system 100 has a processing unit 110, a tunable wavelength light source device 120, an imaging lens 130 and an image sensor 140.

The processing unit 110 is used to receive various types of information acquired by the components of the photoresist material defect detection system 100, run various operations in the photoresist material defect detection system 100, send various types of control signals to each component, and receive All kinds of information from each component. The details of the operation of the processing unit 110 will be described later. The processing unit 110 includes, but is not limited to, for example, a central processing unit (CPU), graphics processing unit (GPU), or other programmable general-purpose or special-purpose microprocessors, Digital Signal Processor (DSP), Programmable Controller, Application Specific Integrated Circuits (ASIC), Programmable Logic Device (PLD) or other similar devices or these The combination of devices for implementation is not limited to this.

The tunable wavelength device 120 is electrically connected to the processing unit 110 and has a controller and a light emitting element. The controller receives the signal sent from the processing unit 110, and then controls the light-emitting element to emit light according to the signal. The controller can be implemented with any control chip, and the present invention is not limited to this. The light-emitting element is, for example, a single light source such as a light-emitting diode, a laser diode, or a matrix composed of one of the two (for example, composed of multiple laser diodes), and the present invention does not take this as Limit, to emit laser light or LED light source, and through the adjustment of the wavelength to emit different colors of adjustable beam. The present invention is not limited to the above-mentioned light-emitting element. In an embodiment of the present invention, the tunable wavelength device 120 can be adjusted in a wavelength range of 400 nm to 800 nm, but the present invention is not limited to this, and is not intended to limit the scope of the present invention.

The imaging lens 130 is configured to allow light to pass through and form an image, for example, including a combination of one or more optical lenses with refractive power. The optical lenses include, for example, bi-concave lenses, bi-convex lenses, meniscus lenses, convex-concave lenses, plano-convex lenses, and plano-concave lenses. Various combinations of non-planar lenses. The present invention does not limit the type and type of the imaging lens 130.

The image sensor 140 is electrically connected to the processing unit 110 and has an image sensing surface. The image sensing surface can sense the image formed by the light to generate a corresponding image. In an embodiment of the present invention, the image sensor 140 is, for example, a complementary metal oxide semiconductor (CMOS) image sensor or a charge coupled device (CCD), but the present invention is not limited to this.

FIG. 2 is a schematic flowchart of a method for detecting defects of a photoresist material according to an embodiment of the present invention. The photoresist material defect detection method of FIG. 2 is at least applicable to the photoresist material defect detection system 100 of FIG. 1, but is not limited thereto. Please refer to FIGS. 1 and 2 at the same time. In the following paragraphs, how to complete the photoresist material defect detection method and the optical behavior in the photoresist material defect detection system 100 through the operational relationship between the above components will be explained in detail .

In step S210, the processing unit 110 receives the center wavelength corresponding to the bandwidth range. In an embodiment of the present invention, the processing unit 110 can receive the center wavelength input by the user. Alternatively, the photoresist material defect detection system 100 can also have a sensing device, such as a spectrometer or a chromaticity detector, to automatically detect the bandwidth range and center wavelength of the photoresist material 10. In addition, the chromaticity detector is electrically connected to the processing unit 110 to input the measured bandwidth range and its corresponding center wavelength to the processing unit 110, and the present invention is not limited to this. In this embodiment, the bandwidth range is 620-750 nm for red light, and the corresponding center wavelength is 685 nm.

In step S220, the processing unit 110 determines the center wavelength of the adjustable beam according to the center wavelength corresponding to the bandwidth range. In the present invention, the center wavelength of the adjustable beam determined by the processing unit 110 is different from the center wavelength corresponding to the bandwidth range. In detail, since the transmittance of light is related to the thickness of the object it penetrates, if the thickness of the photoresist film is different, the transmittance of light will be different accordingly. However, the thickness of the photoresist film is mostly very thin. If the wavelength of the light used is the same as the corresponding center wavelength of the bandwidth range, regardless of whether the photoresist film has uneven thickness, the overall transmittance of the photoresist material is still quite high. It is not easy to highlight differences.

Therefore, in the present invention, the processing unit 110 determines that the center wavelength of the tunable light beam is different from the center wavelength corresponding to the bandwidth range. For example, in an embodiment of the present invention, the processing unit 110 determines that the center wavelength of the tunable beam lies outside the corresponding half-bandwidth of the bandwidth range according to the bandwidth range and its corresponding center wavelength, and is correspondingly within the bandwidth range. The center wavelength of the adjustable beam is determined randomly in the range outside the half-bandwidth. Or, the processing unit 110 will take the corresponding red, blue, and green bandwidth and center wavelength as a reference, and select the smaller overlapping range of the corresponding red, blue, and green bandwidth as the available option. The center wavelength of the light beam is adjusted, and the present invention is not limited to this. In particular, since only a small part of the light beam falling outside the frequency bandwidth will penetrate the photoresist material, by exposing at an appropriate time, the gray scale difference of the uneven film thickness will be more obvious.

In step S230, the tunable wavelength light source device 120 emits a tunable light beam according to the central wavelength, so that the first part of the tunable light beam is absorbed by the photoresist material 10, and the second part of the tunable light beam penetrates the photoresist material 10 Then, a penetrating light beam is formed, and the image is imaged on the image sensing surface of the image sensor 140 through the imaging lens 130 to generate a detection image.

In detail, in this embodiment, the adjustable light beam will travel along the transmission path P1, and the photoresist material 10 will be located in the transmission path P1 of the adjustable light beam. In addition, the penetrating light beam penetrating the photoresist material 10 will travel along the transmission path P2, and the imaging lens 130 and the image sensor 140 will be located on the transmission path P2 of the penetrating light beam. The penetrating light beam passes through the imaging lens 130 and then is transmitted to the image sensing surface to generate a detection image. In this way, the operator can judge whether the photoresist material 10 has uneven film thickness by detecting the image.

In an implementation example of the present invention, if the imaging lens 130 adopts a KOWA focal length lens of 35, and the image sensor 140 adopts Basler model aca2040, the results of wavelength, exposure time, normal part and uneven film thickness part grayscale are as follows Table I: Wavelength (unit: nanometer) Exposure time (unit: microseconds) The gray scale of the normal part (0~255) Gray scale of uneven film thickness (0~255) 400~800 13,500 76 60 400~640 14,300 76 58 400~620 22000 76 56 400~615 27000 76 52 400~610 34000 76 49 400~605 47000 76 46 400~599 73000 76 41 400~595 110000 76 37 400~590 200000 76 30 Table 1: Wavelength, exposure time, gray scale of normal part and uneven film thickness. From Table 1, it can be seen that as the wavelength range of the adjustable beam changes and moves away from the center wavelength, the gray scale difference will become more obvious. It should be noted that the exposure time and grayscale value will be different according to different image sensors 140, and the invention is not limited thereto.

In an embodiment of the present invention, the detected image is sent to the processing unit 110, and the processing unit 110 determines whether the photoresist material 10 has a defect according to the gray scale difference of the detected image.

Specifically, first, the processing unit 110 receives the thickness difference of the photoresist material with the film thickness difference. As mentioned above, the processing unit 110 can receive this thickness difference through user input. Alternatively, the photoresist material defect detection system 100 has a thickness measuring instrument to automatically detect the thickness difference of the photoresist material with defects. In addition, the thickness measuring instrument is electrically connected to the processing unit 110 and transmits the thickness difference to the processing unit 110.

Then, the processing unit 110 obtains the grayscale difference of the center wavelength of the corresponding adjustable beam. The processing unit 110 obtains the corresponding detected images of the photoresist material with the thickness difference according to steps S210 to S230, and further obtains the gray scale difference in the photoresist material with the thickness difference.

Based on this, the processing unit 110 can obtain the standard defect ratio through the thickness difference and the gray scale difference. That is, the ratio of the difference in thickness to the difference in grayscale at the moment when there is a defect. In this way, the processing unit 110 can further determine whether the photoresist material 10 has defects based on the standard defect ratio. It should be noted that a photoresist material with a difference in film thickness may not necessarily be a material with uneven film thickness. In the actual testing standards, if the thickness difference is greater than 0.2 microns, it means that there is a defect of uneven film thickness. If the thickness difference is less than 0.2 microns, it is a tolerable uneven situation. However, in the embodiment of the present invention, the process of obtaining the standard defect ratio only needs to analyze the photoresist material with the film thickness difference, and the present invention does not limit whether the thickness difference of the photoresist material is greater than or less than 0.2 microns.

For example, in the experimental example corresponding to Table 1, the thickness of the normal part of the photoresist material with the thickness difference is 2.044 μm, and the thickness of the part with uneven film thickness is 3.019 μm. Moreover, if the wavelength is in the range of 400 to 595 nm, the gray scale difference between the normal gray scale portion and the film thickness uneven portion is 30, and the actual thickness difference is 1 micron.

Therefore, the processing unit 110 can estimate a difference of 6 per gray scale based on the ratio, and the actual photoresist film difference is about 0.2 microns, and this is set as the standard defect ratio. Based on this, the processing unit 110 detects other photoresist materials according to the standard defect ratio, and determines that the photoresist material has defects with uneven film thickness whenever the gray scale difference is greater than 6 levels.

Moreover, it is worth mentioning that, according to the measured results in Table 1, if the wavelength range becomes smaller, the difference in gray scale difference can be further increased, so that the processing unit 110 can make a more precise judgment.

In addition, in the embodiment of the present invention, the adjustable beam can be simultaneously transmitted to the object to be measured in a point, line or surface manner. In other words, the photoresist material defect detection system can directly scan an entire area, reducing the detection time and improving the time-consuming situation of traditional dot or line scanning.

In summary, the photoresist material defect detection system and method of the present invention can further adjust the center wavelength of the adjustable light beam through the adjustable wavelength light source device, and make the center wavelength of the adjustable light beam different from the corresponding center of the bandwidth range. wavelength. Based on this, the tunable wavelength light source device will use an appropriate center wavelength and bandwidth for detection according to different objects to be tested to enhance the detection effect. Not only that, the photoresist material defect detection system and method can also determine whether there is a defect of uneven film thickness based on the grayscale difference generated on the detection image finally imaged by the adjustable light beam. In addition, the photoresist material defect detection system and method can also reduce the time required for scanning and testing the object under test.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention shall be determined by the scope of the attached patent application.

10: Photoresist material

100: Photoresist material defect detection system

110: processing unit

120: Adjustable wavelength light source device

130: imaging lens

140: image sensor

P1, P2: Transmission path

S210~S230: steps

Fig. 1 shows a schematic diagram of a photoresist material defect detection system according to an embodiment of the present invention. FIG. 2 is a schematic flowchart of a method for detecting defects of a photoresist material according to an embodiment of the present invention.

10: Photoresist material

100: Photoresist material defect detection system

110: processing unit

120: Adjustable wavelength light source device

130: imaging lens

140: image sensor

P1, P2: Transmission path

Claims (11)

A photoresist material defect detection system is suitable for detecting a photoresist material. The photoresist material defect detection system includes: A processing unit that receives a center wavelength corresponding to a bandwidth range, and determines the center wavelength of a tunable beam according to the center wavelength, so that the center wavelength of the tunable beam is different from the center wavelength corresponding to the bandwidth range; A tunable wavelength light source device is electrically connected to the processing unit, and emits the tunable light beam according to the center wavelength, the photoresist material is located on the transmission path of the tunable light beam, and the first part of the tunable light beam is The barrier material absorbs, and the second part of the adjustable light beam penetrates the photoresist material sheet to form a penetrating beam; An imaging lens located on the transmission path of the penetrating light beam; and An image sensor is electrically connected to the processing unit and has an image sensing surface. The penetrating light beam passes through the imaging lens and is imaged on the image sensing surface to generate a detection image. In the photoresist material defect detection system described in item 1 of the scope of patent application, the center wavelength of the adjustable light beam is outside the corresponding half-bandwidth of the frequency bandwidth range. Such as the photoresist material defect detection system described in item 1 of the scope of patent application, wherein the processing unit respectively judges the overlapping range of the bandwidth range and the bandwidth of red light, blue light, and green light, and based on the minimum bandwidth overlap The range determines the center wavelength of the adjustable light beam, where the center wavelength of the adjustable light beam will be the same and the minimum bandwidth overlaps the range corresponding to the red light, the blue light or the green light. The photoresist material defect detection system as described in item 1 of the scope of patent application, wherein: The processing unit also receives the thickness difference of a photoresist material with a film thickness difference, and obtains the grayscale difference of the photoresist material with the film thickness difference corresponding to the adjustable light beam, The processing unit also obtains a standard defect ratio according to the thickness difference and the gray scale difference. For example, in the photoresist material defect detection system described in item 4 of the scope of patent application, the processing unit judges whether the photoresist film has defects according to the standard defect ratio and the gray level difference of the inspection image. The photoresist material defect detection system as described in item 1 of the scope of patent application also includes: A sensing device that senses the center wavelength. A photoresist material defect detection method, which is suitable for detecting a photoresist material, and light in a frequency bandwidth will pass through the photoresist material. The photoresist material defect detection method includes: Receiving a center wavelength corresponding to the bandwidth range; Determine the center wavelength of a tunable beam according to the center wavelength, so that the center wavelength of the tunable beam is different from the corresponding center wavelength of the bandwidth range; and The adjustable light beam is emitted according to the central wavelength, wherein the adjustable light beam is absorbed by the photoresist material and penetrates the photoresist material to form a penetrating beam, and the penetrating beam passes through the imaging lens, Image on the image sensing surface to generate a detection image. According to the method for detecting defects of the photoresist material as described in item 7 of the scope of patent application, the center wavelength of the adjustable light beam is outside the corresponding half-frequency bandwidth of the frequency bandwidth range. The method for detecting defects of the photoresist material as described in item 7 of the scope of patent application, wherein the step of determining the center wavelength of the tunable light beam according to the center wavelength further includes: Determine the overlapping range of the bandwidth range and the bandwidth of red light, blue light, and green light respectively; and The center wavelength of the adjustable light beam is determined according to the range of the smallest overlapped bandwidth, wherein the center wavelength of the adjustable light beam will be the same as the range of the smallest overlapped bandwidth corresponding to the red light, the blue light or the green light. The photoresist material defect detection method described in item 7 of the scope of patent application further includes: Receiving a thickness difference of a photoresist material with a film thickness difference, and obtaining the grayscale difference of the photoresist material with a film thickness difference corresponding to the adjustable beam; and A standard defect ratio is obtained according to the thickness difference and the gray scale difference. The photoresist material defect detection method described in item 10 of the scope of patent application further includes: According to the standard defect ratio and the gray scale difference of the detected image, it is judged whether the photoresist film has defects.

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