TW202129252A - Multi-channel imaging wafer inspection system - Google Patents

Abstract

The wafer inspection system of the present invention is a multi-channel image acquisition design. It can additionally obtain the penetrating image or backside image of the sample in a single acquisition time. And greatly improve the correct rate of detection and save inspection time.

Description

Multi-channel imaging wafer inspection system

The wafer inspection system of the present invention, through the multi-channel imaging design, can additionally obtain the penetration image or the back defect image of the sample to be tested within a single imaging time, so as to improve the detection accuracy and maintain the inspection The purpose of time.

In recent years, for wafer defect detection, in addition to shrinking the scale, it also began to pay attention to the internal and back defects of the wafer substrate (Substrate). Through the improvement of defect problems, it helps to improve the yield of wafers in production and use after packaging. life. For the inspection of the internal and backside defects of the wafer substrate, the current better way is to directly obtain the wafer penetration image, which contains the information of the backside and internal defects, which can quickly identify defective samples, such as the patent CNA109239078A. The second set of light source and imaging mechanism is reached.

However, the problem with the through image is that the light source used must also penetrate the thin film material (blue film) that carries the wafer underneath. As a result, the final through image of the wafer substrate is obtained, and the grayscale value of the image will be similar to the cutting position. , Resulting in the inability to calculate the edge position of the chip substrate stably through the software, so additional image assistance is needed to clearly define the position of the cutting lane. Regarding the definition of the position of the dicing lane, the prior art US20170213796A1 uses transparent electromagnetic radiation to illuminate the back side and inspect the front side to further define the result of the wafer segmentation.

However, in the above two methods, lighting is performed through the underside of the sample, and the image of the sample is obtained from the front. Because the light source has different wavelength requirements for penetrating the carrier wafer material and the substrate itself, it needs to be achieved through switching methods or different optical paths. However, under the condition that the demand for detection speed continues to increase, the method of switching the light source will be limited by the control response time, and the detection speed cannot be increased. If the front and back images of the test sample obtained by moving or turning over, the position error will occur, so It is necessary to redesign the optical path that can take images at the same time, and there is no problem of mutual influence on imaging when taking images.

In order to solve the above-mentioned problems, the main purpose of the present invention is to provide a multi-channel imaging wafer inspection system, which can obtain the edge image of the dicing lane of the divided wafer within a single imaging time, and additionally obtain the cross-section of the wafer. Through the image or the defect image on the back, to provide subsequent software for analysis.

Therefore, the multi-channel imaging wafer inspection system of the present invention mainly includes a first optical module and a second optical module. The above-mentioned optical module may be composed of an optical unit, an illumination unit, and a signal capture unit. The position of the first optical module can be on the upper surface of the wafer, or on the side of the film material under the wafer, and the position of the second optical module is on the opposite side of the first optical module, but the centers of the two optical modules are located On the same central axis. The sample carrying module is used to carry the sample to be tested and is located between the two optical modules.

The above-mentioned first optical module may be composed of a first optical unit, a first lighting unit, and a first signal capture unit. The first optical unit is mainly composed of optical elements to provide the first lighting unit and the first signal capture unit. Take the beam channel of the unit, and this unit can filter out wavelengths other than the imaging requirements; the first illumination unit mainly provides the specific wavelength light source required for imaging. The long range is between 0.01nm~10μm; the first signal capture unit is mainly used to capture the image formed by the light source provided by the first or second optical module.

The above-mentioned second optical module may be composed of a second optical unit, a second lighting unit, and a second signal capture unit. The second optical unit is mainly composed of optical elements to provide a second lighting unit and a second signal capture unit. The beam channel of the unit, and this unit can filter out wavelengths other than the imaging requirements; the second illumination unit mainly provides the specific wavelength light source required for imaging, and the wavelength range is between 0.01nm~10μm; the second signal capture unit is mainly used To capture the image formed by the light source provided by the first or second optical module.

A sample carrying module is arranged between the first and second optical modules to carry the sample to be tested.

Through the combination of the above structure, because the wavelengths used by the first optical unit and the second optical unit are different, when the light source is turned on at the same time, it will not affect the imaging result of the signal capture unit interactively, so it can be used in two light sources. Capture images in the state of being turned on at the same time, no need to switch to achieve, so it can save operation time, and the capture result can obtain the edge image of the dicing lane of the divided wafer, and additionally obtain the through image of the chip or the back defect image , The obtained images are helpful for subsequent analysis of automated equipment software and improve the accuracy of equipment judgment results.

100: Side view of wafer inspection system for multi-channel imaging

101: Central axis

102: Sample to be tested

103: Sample carrying module

110: The first optical module

111: The first optical unit

112: The first lighting unit

113: The first signal capture unit

120: second optical module

121: second optical unit

122: second lighting unit

123: The second signal capture unit

Figure 1 is a schematic diagram of an embodiment of the present invention

Hereinafter, several embodiments of the present invention will be disclosed with figures. In order to clearly illustrate the spirit of the present invention, the following descriptions will be made through practical details. However, these practical details will be described below. The section is not intended to limit the scope of protection of the present invention. In addition, in order to simplify the illustration, some conventional structures and elements will be drawn in a simple manner in the illustration. And if it is possible in implementation, the features of different embodiments can be applied interactively.

Please refer to FIG. 1 for the first embodiment of the present invention. A side view 100 of a wafer inspection system for multi-channel imaging of the present invention includes a first optical module 110, a second optical module 120, and a sample carrying module 103. An optical module 110 is arranged on the upper surface side of the sample 102 to be tested, and the second optical module 120 is arranged on the opposite side of the first optical module 110, and the central positions of the optical modules are all located at the same On the central axis 101, the sample 102 to be tested can be analyzed. In this embodiment, the sample to be tested is a silicon wafer that has been divided.

The composition of the first optical module 110 includes a first optical unit 111, a first lighting unit 112, and a first signal capturing unit 113. The first optical unit 111 is mainly a combination of a lens, a lens and a filter, and the first lighting The unit 112 provides purple light (300~500nm) to illuminate the sample 102 to be tested. The first signal capture unit 113 is mainly an infrared camera; the second optical module 120 is composed of a second optical unit 121 and a second lighting unit 122 And a second signal capture unit 123. The second optical unit 121 is mainly a combination of a lens, a lens and a filter. The second illumination unit 122 provides infrared light (900~1700nm) to illuminate the sample 102 to be tested. The second signal capture The fetching unit 123 is mainly a visible light camera.

Through the above combination, the image captured by the first signal capture unit 113, the light source is the infrared light (900~1700nm) provided by the second illumination unit 122, and it has passed through the optics set inside the second optical unit 121 The combination of lens and filter arranges the light source, providing a uniform light source from the second optical module 120 to the back of the sample 102 to be tested, and then passes through the first optical unit 111 in the first optical module 110. The combination of optical lens and filter makes The light source can be imaged by the first signal capture unit 113, and the imaging result will not be affected by the purple light (300~500nm), so that the penetration image of the sample can be obtained.

In the above combination, the light source of the image captured by the second signal capturing unit 123 is the purple light (300~500nm) provided by the first lighting unit 112, and it has passed through the optical lens provided inside the first optical unit 111 The combination of filters and filters arranges the light source to provide a uniform light source from the first optical module 110 to the front of the sample 102 to be tested, and then passes through the optics set by the second optical unit 121 in the second optical module 120 The combination of lens and filter enables the light source to be imaged in the second signal capture unit 123. Because the purple light (300~500nm) cannot penetrate the divided silicon wafer, it can penetrate the blue film under the wafer. The contour image of the sample can be obtained.

In this embodiment, through the above combination, the result obtained by the first signal capturing unit 113 and the second signal capturing unit 123 at the same time, since the two optical modules are fixed on the same axis 101, the obtained contour image can be It represents the position of the divided wafer in the penetration image, which solves the positioning problem. The penetration image can analyze the condition of the wafer after being cut, and can take images at the same time, which saves time.

Yet another embodiment of the present invention is used to detect that the sample to be tested is an indium phosphide (InP) wafer. The difference from the first embodiment is that the first illumination unit 112 provides visible light (380~780nm) passing through the first The optical unit 111 illuminates the sample 102 to be tested from above, the first signal capture unit 113 is mainly a black and white camera; the second illuminating unit 122 provides infrared light (900~1700nm) through the second optical unit 121 from below to the sample to be tested 102 is illuminated, and the second signal capturing unit 123 is mainly an infrared camera.

Through the above-mentioned combination, the image captured by the first signal capturing unit 113, the light source source is provided by the first lighting unit 112, illuminates the upper surface of the sample 102 to be tested, and The reflected light on the upper surface is imaged through the first optical unit 111, and an image of the upper surface of the sample 102 to be tested can be obtained; and the image captured by the second signal capturing unit 123, the light source is provided by the second lighting unit 122, because Infrared light (900~1700nm) can penetrate the blue film used to fix the sample to be tested, so the reflected light from the lower surface of the sample 102 to be tested can be obtained, and then the second optical unit 121 can be used for imaging. image.

Therefore, in this embodiment, through the above combination, the first signal capturing unit 113 and the second signal capturing unit 123 can simultaneously obtain the front and bottom surface images of the sample to be tested, avoiding the time spent switching during the capturing process. , And the two optical modules are fixed on the same axis 101, which overcomes the alignment problem during the analysis of the imaging results, and can analyze the abnormal position more accurately.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone who is familiar with the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention The scope shall be subject to the definition of the attached patent application scope.

100: Side view of wafer inspection system for multi-channel imaging

101: Central axis

102: Sample to be tested

103: Sample carrying module

110: The first optical module

120: second optical module

Claims (4)

A multi-channel imaging wafer inspection system, through which the positioning information of the edge of the chip can be correctly obtained, and the through image or the back image can be obtained at the same time. The system includes: A first optical module, the module position can be located on the upper surface of the wafer, or on the side of the thin film material below the wafer, the first optical module can be composed of the following units: A first optical unit, which is mainly composed of optical elements, is used to provide the beam channel of the first illumination unit and the signal capture unit, and this unit can filter out wavelengths other than the imaging requirements; A first lighting unit for providing a light source of a specific wavelength, the light source range of the specific wavelength being between 0.01 nm and 10 μm; A first signal capture unit for capturing an image formed by the light source provided by the first or second optical module; A second optical module, the module is located on the opposite side of the first optical module, but the centers of the two optical modules are on the same central axis, the second optical module can be composed of the following units: A second optical unit, which is mainly composed of optical elements, is used to provide the beam channel of the first illumination unit and the signal capture unit, and this unit can filter out wavelengths other than the imaging requirements; A second illuminating unit for providing a light source of a specific wavelength, the light source range of the specific wavelength being between 0.01 nm and 10 μm; A second signal capture unit for capturing an image formed by the light source provided by the first or second optical module; A sample carrying module is used to carry the sample to be tested. The wafer inspection system with multiple optical modules as described in claim 1, wherein the composition of the first optical unit and the second optical unit may be a lens, a lens, an electromagnetic lens, a filter, etc. The wafer inspection system with multiple optical modules as described in claim 1, wherein the composition of the first lighting unit and the second lighting unit can be an electron gun, a halogen lamp, a light emitting diode (LED), or a laser diode (LD) and so on. The wafer inspection system with multiple optical modules as described in claim 1, wherein the composition of the first signal capture unit and the second signal capture unit can be photoelectric sensors, CCD, CMOS, black and white cameras, and color cameras , Shortwave infrared camera, infrared camera, etc.

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