TWI544556B - Visual inspection system and visual inspection method - Google Patents

Description

Visual inspection system and visual inspection method

The present invention relates to a visual inspection system and a visual inspection method, and more particularly to a visual inspection system and a visual inspection method for semiconductor wafer testing.

Photovoltaic components such as single-die packages or multi-die package modules such as light-emitting diodes (LEDs) are mostly subjected to characteristic detection before leaving the factory to detect optical components by probing. Perform electrical functional tests, or sorting photoelectric components based on characteristics such as luminous intensity and hue.

In the process before the above characteristic detection, that is, in the die saw stage, the wafer is first attached to the blue tape, and the blue film is held by the ring frame, and then sent to the wafer for cutting. Cutting on the machine. After the cutting, the blue film is pulled and expanded, so that the individual crystal grains will be arranged on the blue film separately.

However, in the actual expansion process of the blue film, the degree of expansion of each part is irregular and difficult to control, so it tends to make each of the blue films The orientation of the grains is offset, and the degree of azimuth offset of each grain is not the same. This problem of azimuth offset will make the needle and classification stages not smooth (because the test pins and suction cups cannot be exactly aligned with the die). If only the current high-order Automated Optical Inspection (AOI) equipment is used to perform the orientation correction and detection of each crystal, the processing time will be very slow.

Therefore, how to quickly perform the orientation correction of the crystal grains to reduce the processing time of the detection is one of the problems that the industry is currently eager to invest in research and development resources.

The present invention provides a visual inspection system for detecting wafers comprising a plurality of dies. The visual inspection system comprises a carrying platform, a photography module, a light source module and a computer module. The carrier platform is used to carry the wafer. The photography module includes a first photography unit and a second photography unit. The first photographing unit is used to photograph the wafer to obtain an actual wafer image. The second photographing unit is configured to capture one of the crystal grains to obtain an actual crystal image. The light source module and the first photographing unit are respectively located on opposite sides of the carrying platform. The computer module compares the actual wafer image with the standard wafer image to obtain a first angle difference, and then drives the bearing platform to rotate according to the first angle difference, and performs actual grain image and standard grain image. The second angle difference is obtained by comparison, and then the bearing platform is driven to rotate according to the second angle difference.

The present invention further provides a visual inspection method for detecting a wafer including a plurality of dies using a visual inspection system. Visual inspection system includes bearer Platform, camera module and light source module. The photography module includes a first photography unit and a second photography unit. The light source module and the first photographing unit are respectively located on opposite sides of the carrying platform. The visual inspection method comprises: (a) obtaining a real wafer image by capturing a wafer through a first photographing unit; (b) comparing the actual wafer image with a standard wafer image to obtain a first angle difference, and further The angle difference drives the rotation of the carrier platform; (c) after rotating the carrier platform according to the first angle difference, the actual image is obtained by capturing one of the crystal grains through the second photographing unit; and (d) the actual crystal The grain image is compared with the standard grain image to obtain a second angle difference, and the carrier platform is driven to rotate according to the second angle difference.

1, 3‧‧‧ visual inspection system

10, 30‧‧‧ Carrying platform

100‧‧‧Transparent cover

12, 32‧‧‧Photography module

120, 320‧‧‧ first photography unit

122, 322‧‧‧Second photography unit

14, 34‧‧‧Light source module

140, 340a‧‧ ‧Lighting diode

16, 36‧‧‧ sports modules

20‧‧‧ wafer

20a‧‧‧Flang

200‧‧‧ grain

200a‧‧‧electrode

22‧‧‧ ring frame

24‧‧‧Blue film

26‧‧‧Barcode sticker

34a‧‧ ‧ gap

340‧‧‧ light board

18, 38‧‧‧ computer modules

S100~S106‧‧‧Steps

FIG. 1 is a schematic view showing a visual inspection system according to an embodiment of the present invention.

2A is an exploded perspective view showing a part of components of a visual inspection system according to an embodiment of the present invention.

FIG. 2B is a perspective assembled view showing some components of the visual inspection system in FIG. 2A.

FIG. 3 is a schematic diagram showing an actual wafer image taken by the first photographing unit.

Figure 4 is a schematic diagram showing the actual grain image captured by the second camera unit.

FIG. 5 is a view showing a visual inspection system according to another embodiment of the present invention; schematic diagram.

Figure 6 is a perspective view showing a part of components of a visual inspection system according to another embodiment of the present invention.

Fig. 7 is a top view showing the light source module and the second photographing unit in Fig. 5.

FIG. 8 is a flow chart showing a visual detection method according to an embodiment of the present invention.

The embodiments of the present invention are disclosed in the following drawings, and the details of However, it should be understood that these practical details are not intended to limit the invention. That is, in some embodiments of the invention, these practical details are not necessary. In addition, some of the conventional structures and elements are shown in the drawings in a simplified schematic manner in order to simplify the drawings.

Please refer to Figure 1, Figure 2A and Figure 2B first. FIG. 1 is a schematic view showing a visual inspection system 1 according to an embodiment of the present invention. 2A is an exploded perspective view showing a part of components of the visual inspection system 1 according to an embodiment of the present invention. FIG. 2B is a perspective assembled view showing a part of the components of the visual inspection system 1 in FIG. 2A.

As shown in FIGS. 1 to 2B, in the present embodiment, the visual inspection system 1 is used to detect a wafer 20 including a plurality of crystal grains 200. The visual inspection system 1 includes a carrying platform 10, a photography module 12, a light source module 14, a motion module 16, and a computer module 18. In fact, the wafer to be tested The 20 series adheres to the blue tape 24, and the outer edge of the blue film 24 is held by the ring frame 22. The center of the carrying platform 10 of the visual inspection system 1 has a hollow portion (not shown) which is covered by the transparent cover 100 of the carrying platform 10. The visual inspection system 1 carries the ring frame 22 with the carrier platform 10 and aligns the wafer 20 (including the blue film 24) directly above the hollow portion of the carrier platform 10.

In the present embodiment, the photographing module 12 of the visual inspection system 1 includes a first photographing unit 120 and a second photographing unit 122. The first photographing unit 120 and the second photographing unit 12 are both disposed above the carrying platform 10 . When the wafer 20 is photographed using the first photographing unit 120, the second photographing unit 122 is removed. When the second photographing unit 122 is used to photograph the crystal grain 200, the first photographing unit 120 is moved away. The first photographing unit 120 of the photographing module 12 has a first field of view (FOV), and the second photographing unit 122 has a second field of view. The first field of view of the first photographing unit 120 is greater than the second field of view of the second photographing unit 122. Therefore, the first photographing unit 120 of the photographing module 12 can be used to capture the actual wafer image of the entire wafer 20 (as shown in FIG. 3), and the second photographing unit 122 of the photographing module 12 can be used to individually photograph the crystal grains. The actual grain image of 200 (as shown in Figure 4). The first photographing unit 120 and the light source module 14 of the photographing module 12 are respectively located on opposite sides of the carrying platform 10 (ie, upper and lower sides in FIG. 2A). The light source module 14 includes a plurality of light emitting diodes (LEDs) 140, and each of the light emitting diodes 140 substantially emits light toward the wafer 20. Thereby, the light emitted by the light source module 14 can sequentially pass through the hollow portion of the carrying platform 10 and the transparent cover 100 to the wafer 20, so that the first photographing unit 120 of the photographing module 12 is The actual wafer image taken can clearly show the appearance and contour of the wafer 20, and the actual grain image captured by the second photographing unit 122 can clearly show the appearance and contour of the die 200.

In addition, the motion module 16 of the visual inspection system 1 is operatively connected to the carrier platform 10 and electrically connected to the computer module 18. The computer module 18 of the visual inspection system 1 can drive the motion module 16 to move (provide the function of the XY platform) and rotate. Since the carrying platform 10 and the light source module 14 are fixed to each other in the embodiment, the computer module 18 can drive the carrying platform 10 to move with the light source module 14 relative to the camera module 12 by controlling the motion module 16 (ie, the light source) The module 14 moves with the carrying platform 10).

In another embodiment, the carrying platform 10 of the visual inspection system 1 can also be directly transparent, so that the light emitted by the light source module 14 can pass directly through the transparent carrying platform 10 to the wafer 20.

Please refer to Figure 3 and Figure 4. FIG. 3 is a schematic diagram showing an actual wafer image taken by the first photographing unit 120. FIG. 4 is a schematic diagram showing an actual grain image captured by the second photographing unit 122.

As shown in FIG. 3 and FIG. 4, in the embodiment, during the actual detection process, the computer module 18 of the visual inspection system 1 firstly images the actual wafer image captured by the first photographing unit 120. The standard wafer image is compared to obtain a first angle difference, and then the carrier platform 10 is driven to rotate according to the first angle difference (by the motion module 16), and then the actual lens image captured by the second camera unit 122 is captured. A second angle difference is obtained by comparing with a standard grain image, and then the carrier platform 10 is driven to rotate according to the second angle difference (by the motion module 16).

Further, wafer 20 has a first visual characteristic and each die 200 has a second visual characteristic. For example, in the present embodiment, the computer module 18 is set with the flat side 20a of the wafer 20 as the first visual feature of the wafer 20 (see FIG. 3), and is set to two on the die 200. The arrangement direction of the electrodes 200a serves as a second visual feature of the crystal grains 200 (see Fig. 4). However, the selection of the first visual feature of the wafer 20 and the selection of the second visual feature of the die 200 are not limited to the examples of the present embodiment, and may in fact be determined by the process definition of the client.

After the actual wafer image is captured by the first photographing unit 120 of the photographing module 12, the computer module 18 can compare the first visual feature (ie, the flat side 20a) and the standard wafer in the actual wafer image. Obtaining the first angle difference value in the first visual feature of the image, so that the wafer 20 can be quickly rotated according to the first angle difference, so that the first visual feature of the wafer 20 is rotated and The first visual feature of the standard wafer image is in the same position. This action can be regarded as coarse adjustment of the orientation of the die 200. Therefore, the rotation angle of the carrier platform 10 may be large. After that, the computer module 18 can separately capture the actual grain image of each die 200 through the second camera unit 122 of the camera module 12, that is, by comparing the second visual feature in the actual die image (ie, The arrangement direction of the two electrodes 200a of the die 200 is compared with the second visual feature in the standard grain image to obtain the second angle difference, and the film 200 can be rotated according to the second angle difference. The action of the second visual feature of the die 200 is consistent with the position of the second visual feature of the standard die image. This action can be regarded as fine tuning the orientation of the die 200, so the carrier platform 10 may only Need to adjust the angle of rotation a few degrees. Thereby, the vision detecting system 1 of the present invention can quickly perform the orientation correction of the die 200 to reduce the processing time of the detection, so that the subsequent probing and sorting phases can be performed more smoothly.

In another embodiment, the computer module 18 can also be configured to provide the barcode sticker 26 disposed on the wafer 20 as the first visual feature of the wafer 20. Therefore, after the actual image of the wafer is captured by the first photographing unit 120 of the photographing module 12, the computer module 18 can compare the first visual feature in the actual wafer image (ie, the barcode sticker 26 described above) with The first angle difference in the standard wafer image is obtained to obtain the first angle difference, and the wafer 20 can be quickly rotated according to the first angle difference.

In the present embodiment, the first imaging unit 120 of the camera module 12 is a charge-coupled device (CCD), and the first field of view, that is, the camera field of view (FOV) is much larger than the range of the object wafer 20 . . The second photographic unit 122 of the photographic module 12 is a high-order charge-coupled element having a resolution much higher than that of the first photographic unit 120, but the second field of view only needs to be larger than the range of the dies 200.

Please refer to Figure 5, Figure 6, and Figure 7. FIG. 5 is a schematic diagram showing a visual inspection system 3 according to another embodiment of the present invention. Fig. 6 is a perspective view showing a part of components of the visual inspection system 3 according to another embodiment of the present invention. FIG. 7 is a top view showing the light source module 34 and the second photographing unit 322 in FIG. 5.

As shown in FIGS. 5 to 7, in the present embodiment, the visual inspection system 3 is used to detect the wafer 20 including a plurality of crystal grains 200. Visual inspection The measurement system 3 includes a carrier platform 30, a camera module 32, a light source module 34, a motion module 36, and a computer module 38. The wafer 20 to be tested is adhered to the blue film 24, and the outer edge of the blue film 24 is held by the ring frame 22. The center of the carrying platform 30 of the visual inspection system 3 has a hollow portion (covered by the wafer 20, the blue film 24 and the ring frame 22, and thus is not shown). The vision detection system 3 carries the ring frame 22 with the carrier platform 30 and aligns the wafer 20 (including the blue film 24) directly above the hollow portion of the carrier platform 30.

In the present embodiment, the photographing module 32 of the visual inspection system 3 includes a first photographing unit 320 and a second photographing unit 322. The first photographing unit 320 of the photographing module 32 has a first field of view, and the second photographing unit 322 has a second field of view. The first field of view of the first photographing unit 320 is greater than the second field of view of the second photographing unit 322. Therefore, the first photographing unit 320 of the photographing module 32 can be used to capture the actual wafer image of the entire wafer 20 (as shown in FIG. 3), and the second photographing unit 322 of the photographing module 32 can be used to individually photograph the crystal grains. The actual grain image of 200 (as shown in Figure 4). The first photographing unit 320 and the light source module 34 of the photographing module 32 are respectively located on opposite sides of the carrying platform 30 (ie, upper and lower sides in FIG. 6). Thereby, the light emitted by the light source module 34 can be sequentially passed to the wafer 20 through the hollow portion of the carrying platform 30, so that the actual wafer image captured by the first photographing unit 320 of the photographing module 32 can be clearly displayed. The appearance and contour of the wafer 20 are taken out, and the actual grain image captured by the second photographing unit 322 can clearly show the appearance and contour of the die 200.

In addition, the motion module 36 of the visual inspection system 3 is operatively connected to the carrier platform 30 and electrically connected to the computer module 38. Visual inspection system 3 The computer module 38 can drive the motion module 36 to move (providing the function of the XY platform) and rotating. Since the carrying platform 30 in the embodiment is not fixed to the light source module 34, the motion module 36 only drives the carrying platform 30 to move between the camera module 32 and the light source module 34 after being controlled by the computer module 38. (ie, the light source module 34 does not move with the carrying platform 30)

Further, the light source module 34 of the present embodiment is an optical disc. The optical disc is composed of a plurality of light panels 340 spliced to each other. Each of the light panels 340 includes a plurality of light emitting diodes 340a, and each of the light emitting diodes 340a substantially emits light toward the wafer 20. Thereby, the light emitted by the light source module 34 can pass through the hollow portion of the carrying platform 30 to the wafer 20, so that the actual wafer image captured by the first photographing unit 320 of the photographing module 32 can clearly show the crystal. The appearance and contour of the circle 20 and the actual grain image captured by the second camera unit 322 can clearly show the appearance and contour of the die 200. Moreover, with the splicing light source module 34 of the present embodiment, the detecting personnel can correspondingly increase or decrease the number of the light plates 340 according to the size of the wafer 20 to be detected, without replacing the entire light source module 34. . Further, the optical disk in which the light plates 340 are combined has a notch 34a (at the corner of the optical disk as shown in Fig. 7). The second photographing unit 322 of the photographing module 32 is located at the notch 34a.

In addition, the computer module 38 of the present embodiment electrically connects the camera module 32, the light source module 34, and the motion module 36. The functions of the computer module 38 of the present embodiment are the same as those of the computer module 18 of the previous embodiment, and therefore will not be described herein. In summary, after the actual wafer image is captured by the first photographing unit 320 of the photographing module 32, the computer module 38 The first angle difference can be obtained by comparing the first visual feature in the actual wafer image (ie, the flat edge 20a) with the first visual feature in the standard wafer image, thereby rapidly increasing the first angle difference according to the first angle difference. The wafer 20 is turned positive. Then, the computer module 38 can separately capture the actual grain image of each die 200 through the second camera unit 322 of the camera module 32, that is, by comparing the second visual feature in the actual die image (ie, The arrangement direction of the two electrodes 200a of the die 200 is compared with the second visual feature in the standard die image to obtain a second angular difference, and the captured die 200 can be rotated according to the second angular difference. Thereby, the visual inspection system 3 of the present invention can quickly perform the orientation correction of the die 200 to reduce the processing time of the detection, so that the subsequent needle measurement and classification phases can be performed more smoothly.

In another embodiment, the computer module 38 can also be configured to provide the barcode sticker 26 disposed on the wafer 20 as the first visual feature of the wafer 20. Therefore, after the actual wafer image is captured by the first photographing unit 320 of the photographing module 32, the computer module 38 can compare the first visual feature of the wafer 20 in the actual wafer image (ie, the barcode described above). The sticker 26) obtains a first angular difference from the first visual feature in the standard wafer image, and thereby rapidly corrects the wafer 20 according to the first angular difference.

Please refer to FIG. 8 , which is a flow chart showing a visual detection method according to an embodiment of the present invention.

As shown in FIG. 8, in the present embodiment, the visual inspection method detects a wafer including a plurality of crystal grains by using a visual inspection system. The visual inspection system comprises a carrying platform, a photography module and a light source module. The photography module includes a first photography unit and a second photography unit. Light source module and first photography The units are respectively located on opposite sides of the carrying platform. The visual inspection method includes steps S100 to S106 as follows.

Step S100: Obtain an actual wafer image by capturing a wafer through the first photographing unit.

Step S102: Comparing the actual wafer image with the standard wafer image to obtain a first angle difference, and driving the carrier platform to rotate according to the first angle difference.

Step S104: Obtain an actual crystal image by taking one of the crystal grains through the second photographing unit.

Step S106: comparing the actual grain image with the standard grain image to obtain a second angle difference, and then driving the bearing platform to rotate according to the second angle difference.

Regarding the specifications of the first photographic unit and the second photographic unit, and the selection of the first visual feature and the second visual feature, reference may be made to the above related content, and details are not described herein again.

From the above detailed description of the specific embodiments of the present invention, it can be clearly seen that the photographic module used in the visual inspection system of the present invention includes a first photographic unit and a second photographic unit having different fields of view. Among them, the first photographic unit with a larger field of view is used to capture the appearance of the entire wafer, and the second photographic unit with a smaller field of view is used to individually capture the appearance of the dies. After obtaining the actual wafer image through the first photographing unit, the first visual feature in the actual wafer image (for example, the flat edge of the wafer or the barcode sticker on the wafer) and the standard wafer image can be compared. The first visual feature obtains a first angular difference, and the wafer can be quickly rotated according to the first angular difference The action, which can be considered as a coarse adjustment of the orientation of the grain. Then, the actual image of the grain is obtained through the second camera unit, that is, by comparing the second visual feature in the actual grain image (for example, two electrodes on the die) and the second visual feature in the standard grain image. The second angle difference is obtained, and the captured crystal grain can be rotated according to the second angle difference. This action can be regarded as fine adjustment of the orientation of the crystal grain. Thereby, the visual inspection system of the present invention can quickly perform the orientation correction of the crystal grains to reduce the processing time of the detection, so that the needle measurement and classification stages can be performed more smoothly.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

10‧‧‧Loading platform

100‧‧‧Transparent cover

120‧‧‧First Photographic Unit

14‧‧‧Light source module

140‧‧‧Lighting diode

16‧‧‧Sports module

20‧‧‧ wafer

22‧‧‧ ring frame

24‧‧‧Blue film

26‧‧‧Barcode sticker

Claims (9)

A visual inspection system for detecting a wafer adhered to a blue film, the wafer comprising a plurality of dies, the visual inspection system comprising: a carrier platform for carrying the wafer, the carrier platform having a hollow portion a photographic module comprising: a first photographic unit for capturing the wafer to obtain an actual wafer image; and a second photographic unit for capturing one of the dies to obtain an actual a light source module; the light source module and the first photographing unit are respectively located on opposite sides of the carrying platform, wherein a light emitted by the light source module passes through the hollow portion to the wafer, so that the first The actual wafer image captured by the photographing unit can clearly show the appearance and contour of the wafer, and the actual grain image captured by the second photographing unit can clearly show the appearance and contour of the crystal grain; And a computer module for comparing the actual wafer image with a standard wafer image to obtain a first angle difference, and driving the carrier platform to rotate according to the first angle difference, and The actual grain size image for comparison with a standard die image to obtain a second angle difference value, the difference in turn drives the second carrier based on the angular rotation of the platform. The visual inspection system of claim 1, wherein The bearing platform and the light source module are fixed to each other, and the visual inspection system further comprises a motion module, the motion module is operatively connected to the carrying platform, and is driven by the computer module to drive the carrying platform and the light source module The groups move together relative to the camera module. The visual inspection system of claim 1, further comprising a motion module, the motion module being operatively connected to the load platform for being controlled by the computer module to drive the load platform to move to the photography module Between the group and the light source module. The visual inspection system of claim 3, wherein the light source module is an optical disc, and the optical disc is composed of a plurality of optical panels being spliced to each other. The visual inspection system of claim 4, wherein the optical disc has a gap and the second photographing unit is located above the gap or the carrying platform. The visual inspection system of claim 1, wherein the wafer has a first visual feature, and the computer module compares the first visual feature with the standard wafer in the actual wafer image. The first visual feature is obtained by the first visual feature in the image, the first visual feature being a flat edge of the wafer or a bar code sticker disposed on the wafer. The visual inspection system of claim 1, wherein a second visual feature of each of the plurality of dies, the computer module obtaining the second visual feature by comparing the second visual feature in the actual granule image with the second visual feature in the standard granule image The second angle difference is a direction in which the two electrodes on the die are photographed by the second photographing unit. The visual inspection system of claim 1, wherein the first photographing unit is a charge coupled device and has a first field of view, the first field of view being greater than a range of the wafer, and the second photographing unit is a high-order charge coupled device having a second field of view, the resolution of the second camera unit being greater than the resolution of the first camera unit, and the second field of view being greater than the range of any of the plurality of grains. A visual inspection method for detecting a wafer comprising a plurality of dies adhered to a blue film by using a visual inspection system, the visual inspection system comprising a carrier platform, a photographic module and a light source module, the carrier platform having a The photographic module includes a first photographic unit and a second photographic unit. The light source module and the first photographic unit are respectively located on opposite sides of the carrying platform. The visual detecting method comprises: (a) via The first photographing unit captures the wafer to obtain an actual wafer image, wherein a light emitted by the light source module passes through the hollow portion to the wafer, so that the actual crystal taken by the first photographing unit The circular image clearly shows the appearance and contour of the wafer; (b) the actual wafer image is compared with a standard wafer image. Obtaining a first angle difference, and driving the bearing platform to rotate according to the first angle difference; (c) after rotating the carrier platform according to the first angle difference, capturing the crystal grains through the second photographing unit Obtaining an actual grain image, wherein the light passing through the hollow portion to the wafer further causes the actual grain image captured by the second camera unit to clearly show the appearance of the die And (d) comparing the actual grain image with a standard grain image to obtain a second angle difference, and driving the carrier platform rotation according to the second angle difference.