JP2004347525A - Visual inspection method for semiconductor chip and device therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a visual inspection method for semiconductor chips and a device therefor which can conduct a visual inspect of the rear side of a semiconductor chip from only the surface of the chip. <P>SOLUTION: The visual inspection device irradiates infrared light to a semiconductor chip 1 from an infrared lamp 12. An image of the rear side of the chip transmitted through the semiconductor chip 1 is taken into an infrared camera 9 located at the front side of the semiconductor chip 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an appearance inspection method and an apparatus for imaging a semiconductor chip and performing an appearance inspection based on the image.
[0002]
[Prior art]
In the inspection of a semiconductor chip, for example, in the case of a semiconductor chip having a pressure-sensitive portion (thin-film processed portion) made of silicon or the like, such as a semiconductor pressure sensor, inspection is performed from both sides of the semiconductor chip.
[0003]
In the inspection process, in addition to the case of visual inspection, as an example of an automated apparatus, as shown in a schematic configuration diagram of FIG. 6, the inspection apparatus is attached on a wafer sheet 51 mounted on a movable mounting table 50. Illuminating means 53 and 54 for irradiating visible light to both the front and back directions of the semiconductor chip 52, and an optical system 55 for receiving reflected light from the semiconductor chip 52 illuminated by the illuminating means, 56 and CCD cameras 57 and 58 for receiving the light guided by the optical system. Image information captured by the CCD camera is input to an image processing device 59, where image processing is performed, and the image information is compared with a reference value to determine good or bad.
[0004]
As an example of a semiconductor component inspection apparatus in which a CCD camera is provided on only one side, as shown in FIG. 7, the inspection apparatus includes a microscope 61 and a semiconductor attached to the microscope 61 to be inspected. A CCD color camera (imaging means) 73 for acquiring an image formed by reflected light from one side of the pressure sensor (semiconductor component) 60 by the coaxial incident illumination 72 and transmitted light by the transmitted illumination 71; An image processing device 63 that captures an acquired image and performs image analysis by image processing, a TV monitor 64 that displays the acquired image and the image analysis result, and performs data processing based on the image analysis result to determine each inspection item. And a personal computer 65. In this case, the image processing device 63, the TV monitor 64, and the personal computer 65 correspond to the inspection unit (for example, see Patent Document 1).
[0005]
Also, as another example of a semiconductor component inspection apparatus in which a CCD camera is provided on only one side, a sample observation apparatus that uses infrared light as irradiation light to observe a crystal defect of a semiconductor wafer, although not an appearance inspection, is also available. It is disclosed (see Patent Document 2).
[0006]
[Patent Document 1]
(JP-A-10-318722, paragraphs 0017 to 0023, FIG. 1).
[0007]
[Patent Document 2]
(Japanese Patent Publication No. Sho 62-45965, page 2 Figure 1)
[0008]
[Problems to be solved by the invention]
However, in the inspection method of each inspection apparatus described above, when inspecting the back surface side of the semiconductor chip, a light source is provided below the back surface to illuminate the back surface of the semiconductor chip. Therefore, in the related art, it is necessary to dispose a light source or an optical system for guiding light from the light source below the mounting table on which the semiconductor chip is mounted. This complicates the inspection apparatus and is not preferable as the structure of the apparatus.
[0009]
The present invention has been made based on these circumstances, and it is an object of the present invention to provide a semiconductor chip appearance inspection method and apparatus capable of inspecting the back surface in the semiconductor chip appearance inspection only from the front side of the semiconductor chip. .
[0010]
[Means for Solving the Problems]
According to the present invention, an irradiation step of irradiating the semiconductor chip with infrared light from the front side of the semiconductor chip,
An infrared light camera provided on the front surface side of the semiconductor chip by irradiating the front surface of the semiconductor chip by the irradiation step and transmitting an image of the rear surface by infrared light that has passed through the semiconductor chip and reached the rear surface; An imaging step to capture in
An image processing step of processing image information taken into the infrared light camera in the imaging step by an image processing device.
[0011]
Further, according to the present invention, a first irradiation step of irradiating the semiconductor chip with infrared light from the front side of the semiconductor chip;
The image of the back surface is formed on the front surface side of the semiconductor chip by the infrared light which is irradiated on the front surface of the semiconductor chip by the first irradiation step and which is transmitted through the semiconductor chip and reaches the back surface. A first imaging step of capturing with an external light camera;
A second irradiation step of irradiating the semiconductor chip with visible light from the front side of the semiconductor chip;
A second imaging step of capturing an image of the surface of the semiconductor chip irradiated by the second irradiation step with a visible light camera provided on the front side of the semiconductor chip;
An image processing step of processing image information captured by the infrared light or visible light camera in the first and second imaging steps with an image processing apparatus. .
[0012]
According to the present invention, there is provided the semiconductor chip appearance inspection method, wherein the infrared light uses a wavelength of a unique infrared light transmitting region corresponding to the semiconductor chip.
[0013]
Further, according to the present invention, there is provided a mounting table for mounting the semiconductor chip, and an optical system arranged to face the mounting table, and captures an image of the semiconductor chip into a camera via the optical system, A semiconductor chip appearance inspection device that inspects the appearance of the semiconductor chip based on the image,
The optical system is provided with a light source for irradiating the semiconductor chip with infrared light, and the camera is an infrared camera having sensitivity to infrared light. This is a chip appearance inspection device.
[0014]
Further, according to the present invention, there is provided a mounting table for mounting the semiconductor chip, and an optical system arranged to face the mounting table, and captures an image of the semiconductor chip into a camera via the optical system, A semiconductor chip appearance inspection device that inspects the appearance of the semiconductor chip based on the image,
The optical system includes a visible light source, and a first optical system connected to a visible light camera having sensitivity to visible light, and an infrared light source that emits infrared light, and And a second optical system connected to an infrared light camera having sensitivity to infrared light.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
The inventor has studied in advance a method of inspecting the back surface of a semiconductor chip only from the front side of the semiconductor chip when inspecting the appearance of the semiconductor chip. As a result, the infrared light is used as the inspection light, and the image of the back side of the semiconductor chip is imaged with an infrared camera while the infrared light is irradiated on the semiconductor chip. I confirmed that I can do it.
[0017]
Note that infrared light has a unique transmission region corresponding to each material, which is 1200 to 1500 nm for single crystal silicon, 1800 to 2300 nm for Ge, and 900 to 1800 nm for GaAs. Therefore, when inspecting the appearance of the semiconductor chip, a light source and an infrared light camera that are sensitive to the wavelength of the infrared light transmission region specific to the semiconductor chip are used.
[0018]
Next, the semiconductor chip appearance inspection apparatus will be described with reference to a schematic configuration diagram of a main part of the apparatus shown in FIG.
[0019]
A semiconductor chip 1 to be inspected is affixed to a translucent wafer sheet 2 in an aligned state, and is mounted on a mounting table 3 which is movable in a predetermined direction. Above the mounting table 3, an infrared light optical system (optical system) 4 is arranged at a predetermined distance. In the infrared light optical system 4, a condenser lens 6 is provided inside an optical tube 5 at a position facing the semiconductor chip 1, and a half mirror 7 is sequentially arranged above the optical axis of the condenser lens 6. , An inspection lens 8 and an inspection camera (infrared light camera) 9 which is a CCD camera and has sensitivity to infrared rays. The output from this test is connected to the image processing device 11. A personal computer (not shown) for information processing is connected to the image processing apparatus 11. Further, an infrared light lamp 12, which is a light source for irradiating infrared light, is disposed in front of the half mirror 7 on the reflection optical axis.
[0020]
With these configurations, at the time of visual inspection, the mounting table 3 on which the semiconductor chip 1 is mounted moves while being controlled by the control means (not shown), and the semiconductor chip 1 to be inspected moves to the position of the optical axis of the condenser lens 6. To stop. When the infrared light lamp 12 is turned on, the infrared light emitted from the infrared light lamp 12 is reflected by the half mirror 7 and illuminates the surface of the semiconductor chip 1 via the condenser lens 6. Further, since the light is infrared light, the light passes through the semiconductor chip 1 and illuminates the back surface. The image on the back surface of the semiconductor chip 1 is focused on the light receiving surface of the inspection camera 9 via the condenser lens 6, the half mirror 7, and the inspection lens 8, and is captured (imaging step). Image information of the back surface of the semiconductor chip 1 captured by the inspection camera 9 is input to the image processing device 11. The image processing device 11 compares the image with a reference image of a non-defective product stored in advance to determine good or bad (image processing step).
[0021]
In some cases, the image of the inspection camera 9 may not be determined by the image processing apparatus 11, but may be determined by visually observing the image of the inspection camera 9 on a monitor or the like.
[0022]
FIGS. 2A and 2B are explanatory diagrams at the time of image processing in the image processing apparatus 11. FIG. 2A-1 shows the back surface shape of a non-defective semiconductor chip 1 having no defects. Therefore, FIG. 2A-2 also shows an image obtained by capturing the defect with the inspection camera 9 and processing it with the image processing apparatus 11. As mentioned, there are no defects. On the other hand, FIG. 2B-1 shows a back surface shape of a defective semiconductor chip 1 having a defect 13 at a corner. Accordingly, an image obtained by capturing the image with the inspection camera 9 and processing the image with the image processing apparatus 11 also has a defect 13 at the corner as shown in FIG.
[0023]
Next, as a modification of the above-described embodiment, a method and an apparatus for visually inspecting both the front surface and the back surface of the semiconductor chip 1 will be described. In this case, the visual inspection of the front surface of the semiconductor chip 1 is performed by a visible light optical system (second optical system) described later, and the visual inspection of the back surface is performed by the infrared light optical system 4 (first optical system) substantially similar to the above. Use
[0024]
FIG. 3 is a schematic configuration diagram of a main part of a modified example of the semiconductor chip appearance inspection device. A semiconductor chip 1 to be inspected is affixed to a translucent wafer sheet 2 in an aligned state, and is mounted on a mounting table 3 which is movable in a predetermined direction. Above the mounting table 3, an imaging prism 14 is arranged at a predetermined distance. On the upper surface of the imaging prism 14, a visible light optical system 15 and an infrared light optical system 4 are arranged side by side. The infrared light optical system 4 has the same basic structure as the infrared light optical system 4 used in the above-described embodiment (however, there is no condenser lens 6). Therefore, the individual description is omitted.
[0025]
On the other hand, the visible light optical system 15 has the same structure as the infrared light optical system 4 except that the light source and the inspection camera correspond to the visible light region, respectively.
[0026]
That is, a half mirror 7a and an inspection lens 8a are provided from the lower side to the upper side at a position on the optical axis that goes straight through the half mirror 7a inside the optical cylinder 5a. A visible light camera 16 which is a CCD camera serving as a surface is arranged. A visible light lamp 17 for irradiating visible light is disposed in front of the half mirror 7a on the reflection optical axis.
[0027]
The output sides of the visible light camera 16 and the infrared light camera 9 of the infrared light optical system 4 are connected to the image processing device 11.
[0028]
With these configurations, at the time of visual inspection, the mounting table 3 on which the semiconductor chip 1 is mounted moves while being controlled by the control means (not shown), and the semiconductor chip 1 to be inspected moves to the position of the optical axis of the imaging prism 14. Stop. First, when the infrared light lamp 12 is turned on, infrared light emitted from the infrared light lamp 12 is reflected by the half mirror 7 and illuminates the surface of the semiconductor chip 1 via the imaging prism 14. To irradiate the back surface. An image on the back surface of the semiconductor chip 1 is focused on the light receiving surface of the inspection camera 9 via the imaging prism 14, the half mirror 7, and the inspection lens 8 and taken in (first imaging step). Image information of the back surface of the semiconductor chip 1 taken into the inspection camera 9 is input to the image processing device 11, and the image processing device 11 compares the image information with a reference image of a non-defective product stored in advance to determine good or bad. (First image processing step).
[0029]
Next, the infrared light lamp 12 is turned off and the visible light lamp 17 is turned on. Accordingly, the visible light emitted from the visible light lamp 17 is reflected by the half mirror 7 a and illuminates and irradiates the surface of the semiconductor chip 1 via the imaging prism 14. The illuminated image of the surface of the semiconductor chip 1 is focused on the light receiving surface of the visible light camera 16 via the half mirror 7a and the inspection lens 8a and is taken in (second imaging step). The image information of the surface of the semiconductor chip 1 captured by the visible light camera 16 is input to the image processing device 11, and the image processing device 11 compares the image information with a reference image of a non-defective product stored in advance to determine good or bad. (Second image processing step).
[0030]
Note that, in this case, the image of the back surface of the semiconductor chip 1 was captured first, and then the image of the front surface of the semiconductor chip 1 was captured. It goes without saying that an image of the front surface of the chip 1 may be captured, and then an image of the back surface of the semiconductor chip 1 may be captured.
[0031]
FIGS. 4A to 4C and FIGS. 5A to 5C are explanatory diagrams at the time of image processing in the image processing apparatus 11. FIG. 4A shows the shape of the surface of a non-defective semiconductor chip 1, and FIG. FIG. 4C shows an image processed by the image processing apparatus 11. In this case, since it is a non-defective product, there is no defect 13 in appearance on both the front surface and the back surface. Therefore, no defect 13 exists in the image processed by the image processing apparatus 11.
[0032]
On the other hand, FIG. 5A shows the surface shape of a defective product of the semiconductor chip 1, and FIG. 5B shows the back surface shape of the defective product. FIG. 5C shows an image processed by the image processing apparatus 11. In this case, the surface shape has a defect 13 at a corner portion, and the rear surface also has a defect 13 at a corner portion different from the front surface.
[0033]
Therefore, an image obtained by processing the image information of the front surface taken in from the visible light optical system 15 and the image information of the back surface taken in from the infrared light optical system 4 by the image processing device 11 is as shown in FIG. Then, a pattern of the defect 13 is displayed at a position corresponding to a corner where the defect 13 exists between the front surface and the back surface. This pattern is subjected to pattern matching with a non-defective reference image stored in advance in the image processing apparatus 11 to determine good or bad.
[0034]
As described above, according to the above-described embodiment, when inspecting the appearance of the front and back surfaces of the semiconductor chip 1, the semiconductor chip on the wafer sheet is automatically inspected by the inspection system only from above (front side). Becomes possible. Thereby, the inspection can be performed quickly and accurately in the manufacturing process. Further, the configuration of the appearance inspection apparatus is simplified, and space can be saved on the production process line.
[0035]
Thereby, an improvement in the productivity of the semiconductor chip can be realized.
[0036]
【The invention's effect】
According to the present invention, the inspection of the back surface in the appearance inspection of the semiconductor chip can be performed only from the front surface side of the semiconductor chip. Thereby, the inspection can be performed quickly and accurately in the manufacturing process.
[0037]
In addition, the configuration of the appearance inspection apparatus is simplified, and space can be saved in the production process line.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a main part of a semiconductor chip appearance inspection device of the present invention.
FIGS. 2A and 2B are explanatory diagrams at the time of image processing by an image processing apparatus.
FIG. 3 is a schematic configuration diagram of a main part of a modified example of the semiconductor chip appearance inspection device of the present invention.
FIGS. 4A to 4C are diagrams illustrating image processing performed by the image processing apparatus.
FIGS. 5A to 5C are explanatory diagrams at the time of image processing in the image processing apparatus.
FIG. 6 is a schematic configuration diagram of a main part of a conventional semiconductor chip appearance inspection device.
FIG. 7 is a schematic configuration diagram of a main part of a conventional semiconductor chip appearance inspection device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Semiconductor chip, 4 ... Infrared light optical system, 9 ... Inspection camera, 11 ... Image processing apparatus, 12 ... Infrared light lamp, 13 ... Defect, 14 ... Imaging prism, 15 ... Visible light optical system, 16 ... Visible Optical camera, 17 ... Visible light lamp.

Claims (5)

An irradiation step of irradiating the semiconductor chip with infrared light from the front side of the semiconductor chip,
An infrared light camera provided on the front surface side of the semiconductor chip by irradiating the front surface of the semiconductor chip by the irradiation step and transmitting an image of the rear surface by infrared light that has passed through the semiconductor chip and reached the rear surface; An imaging step to capture in
An image processing step of processing image information captured by the infrared light camera in the image capturing step by an image processing device. A first irradiation step of irradiating the semiconductor chip with infrared light from the front side of the semiconductor chip;
The image of the back surface is formed on the front surface side of the semiconductor chip by the infrared light which is irradiated on the front surface of the semiconductor chip by the first irradiation step and which is transmitted through the semiconductor chip and reaches the back surface. A first imaging step of capturing with an external light camera;
A second irradiation step of irradiating the semiconductor chip with visible light from the front side of the semiconductor chip;
A second imaging step of capturing an image of the surface of the semiconductor chip irradiated by the second irradiation step with a visible light camera provided on the front side of the semiconductor chip;
An image processing step of processing image information captured by the infrared light or visible light camera in the first and second imaging steps by an image processing apparatus. The semiconductor chip appearance inspection method according to claim 1, wherein the infrared light uses a wavelength of a unique infrared light transmission region corresponding to the semiconductor chip. A mounting table on which the semiconductor chip is mounted, and an optical system disposed opposite to the mounting table, an image of the semiconductor chip is taken into a camera via the optical system, and the image of the semiconductor chip is obtained by the image. A semiconductor chip appearance inspection device for inspecting the appearance,
The optical system is provided with a light source for irradiating the semiconductor chip with infrared light, and the camera is an infrared camera having sensitivity to infrared light. Chip visual inspection device. A mounting table on which the semiconductor chip is mounted, and an optical system disposed opposite to the mounting table, an image of the semiconductor chip is taken into a camera via the optical system, and the image of the semiconductor chip is obtained by the image. A semiconductor chip appearance inspection device for inspecting the appearance,
The optical system includes a visible light source, and a first optical system connected to a visible light camera having sensitivity to visible light, and an infrared light source that emits infrared light, and And a second optical system connected to an infrared light camera having sensitivity to infrared light.

Images