JP2017166839A - Image inspection device and image inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a photographing time to less than conventional.SOLUTION: The present invention comprises: a movable table 1 on which a wafer 10 having a plurality of chips 11 is placed, and which is movable independently in two axial directions; a camera 3 for photographing a photograph area; a movement unit 51 for moving the movable table 1 so that a plurality of photograph points set to the chips 11 are sequentially adjusted to the photograph area; and a photograph unit 52 for causing the photograph area to be photographed for each photograph point by the camera 3 after the movable table 1 is moved by the movement unit 51 and settled, the movement unit 51 moving the movable table 1 in the order in which the direction of movement for each photograph point is a single axial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image inspection apparatus and an image inspection method for inspecting an appearance of a plurality of chips on a wafer.

  2. Description of the Related Art Conventionally, there has been known an image inspection apparatus (appearance inspection apparatus) that performs an external image inspection on a plurality of chips included in a wafer (for example, see Patent Document 1). In this image inspection apparatus, a chip is photographed by a camera, and the appearance of the chip is inspected using image processing.

JP 2010-164534 A

  In this image inspection apparatus, a wafer is placed on a movable table 1 that can move independently in two axial directions as shown in FIG. 7 to position the wafer. In FIG. 7, reference numeral 101 represents an X-axis actuator, and reference numeral 102 represents a Y-axis actuator.

Here, when the field of view (imaging area) of the camera is small with respect to the size of the chip, the image inspection apparatus captures and superimposes a plurality of images on one chip to obtain an image of the entire chip. . For example, in FIG. 8, from the viewpoint of the relationship between the camera performance and the field of view and the size of the chip 11, the important inspection points on the chip 11, etc., a total of 7 points including 6 points around the chip 11 and 1 center part are taken as shooting points. It shows the case of setting. Note that reference numeral 111 in FIG. 8 indicates an alignment mark which is a mark attached near the first photographing point.
Then, the movable table 1 is moved so that the photographing points on the chip 11 are sequentially matched with the photographing region of the camera, and each photographing point is photographed. At this time, the photographing points are generally photographed in the order shown in FIG. FIG. 9 shows an example of an image obtained by photographing each photographing point. And the image of the whole chip | tip 11 is acquirable by superimposing the figure shown in FIG.

  However, in the case of the shooting sequence shown in FIG. 8, it is movable when the third shooting point is set to the shooting area, the fifth shooting point is set to the shooting area, and the seventh shooting point is set to the shooting area. It is necessary to operate the table 1 on two axes simultaneously. For this reason, there is a problem that the settling time after the positioning of the chip 11 becomes long, and as a result, the entire photographing time becomes long. The settling time refers to the time until the movable table 1 stops oscillating after the movable table 1 is moved and stopped.

  The present invention has been made in order to solve the above-described problems, and an image inspection apparatus and an image inspection method capable of shortening the photographing time as compared with the conventional image inspection for a plurality of chips of a wafer. The purpose is to provide.

  An image inspection apparatus according to the present invention includes a movable table on which a wafer having a plurality of chips is placed and movable independently in two axial directions, a camera for photographing a photographing region, and a plurality of chips set for the chips. A moving unit that moves the movable table so that the photographing points are sequentially aligned with the photographing region, and a photographing unit that photographs the photographing region with the camera after the movable table is moved and settled by the moving unit for each photographing point. The moving unit is configured to move the movable table in the order in which the moving direction for each photographing point is the one-axis direction.

  According to this invention, since it comprised as mentioned above, in the image inspection of the external appearance with respect to the several chip | tip which a wafer has, the imaging | photography time can be shortened conventionally.

1A and 1B are diagrams showing a configuration example of an image inspection apparatus according to Embodiment 1 of the present invention, and are a top view and a side view. It is a figure which shows the structural example of the control part in Embodiment 1 of this invention. It is a flowchart which shows the imaging | photography operation example of the chip | tip by the image inspection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the imaging | photography order of the chip | tip by the image inspection apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the effect by the image inspection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows another example of the imaging | photography order of the chip | tip by the image inspection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the structural example of a movable table. It is a figure which shows the imaging | photography order of the chip | tip by the conventional image inspection apparatus. It is a figure which shows an example of the image image | photographed with the image inspection apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration example of an image inspection apparatus according to Embodiment 1 of the present invention.
As shown in FIG. 1, the image inspection apparatus includes a movable table 1, a microscope 2, a camera 3, an illumination 4, and a control unit 5. FIG. 1 shows a state where the wafer 10 is placed on the movable table 1.

  The movable table 1 has a wafer 10 placed thereon and can move independently in two axial directions. The movable table 1 is configured to be movable independently in the two-axis (X-axis, Y-axis) directions in the horizontal plane by the X-axis actuator 101 and the Y-axis actuator 102, for example, as in FIG.

  The wafer 10 has a plurality of chips 11. In the image inspection apparatus, a plurality of shooting points are set for the chip 11 in terms of the relationship between the performance and field of view (shooting area) of the camera 3 and the size of the chip 11, important inspection points on the chip 11, and the like. ing. On the chip 11, an alignment mark 111 is attached near the first photographing point (see FIG. 4 and the like).

  The microscope 2 enlarges the photographing area of the camera 3. The microscope 2 is provided with an inspection lens used for image inspection of the appearance of the chip 11 on the wafer 10. As this inspection lens, for example, a 10 × objective lens is used.

The camera 3 is attached to the microscope 2 and performs imaging of an imaging area enlarged by the microscope 2.
The illumination 4 illuminates the shooting area of the camera 3. At this time, the illumination 4 irradiates light of a light amount necessary for photographing the wafer 10 located on the photographing region.

  The control unit 5 controls the operation of each unit of the image inspection apparatus. In the following, only the functions related to photographing of the chip 11 among the functions of the control unit 5 will be described. As shown in FIG. 2, the control unit 5 includes a moving unit 51 and a photographing unit 52 as functions relating to photographing of the chip 11. The control unit 5 is realized by a processing circuit such as a system LSI or a CPU that executes a program stored in a memory or the like.

The moving unit 51 moves the movable table 1 so that a plurality of shooting points set for the chip 11 are sequentially aligned with the shooting area. At this time, the moving unit 51 moves the movable table 1 in the order in which the moving direction for each photographing point is the one-axis direction.
The photographing unit 52 causes the camera 3 to photograph a photographing region after the movable table 1 is moved and settled by the moving unit 51 for each photographing point.

  Next, an example of the photographing operation of the chip 11 by the image inspection apparatus configured as described above will be described with reference to FIGS. In the following, for each chip 11, a case where a total of 7 points including 6 points around the chip 11 and 1 central part are photographed is shown. Further, in the moving unit 51, for example, as shown in FIG. 4, a shooting order in which the moving direction for each shooting point is a uniaxial direction is set in advance. The photographing point closest to the alignment mark 111 on the chip 11 is set as the first photographing point.

  In the example of the photographing operation of the chip 11 by the image inspection apparatus, as shown in FIG. 3, first, the moving unit 51 moves the movable table 1 so that the photographing point that is the photographing object of the chip 11 is aligned with the photographing region ( Step ST301). At this time, the moving unit 51 moves the movable table 1 only in the one-axis direction, thereby matching the shooting point that is the shooting target with the shooting region.

  Next, after the movable table 1 is settled, the photographing unit 52 causes the camera 3 to photograph the photographing region (step ST302). As a result, the shooting point that is the shooting target is shot.

  Next, the moving unit 51 determines whether or not shooting for all shooting points on the chip 11 has been completed (step ST303). In step ST303, when the moving unit 51 determines that there is an unphotographed shooting point, the moving unit 51 sets the next shooting point as a shooting target, and the sequence returns to step ST301.

  On the other hand, in Step ST303, when the moving unit 51 determines that shooting for all the shooting points on the chip 11 is completed, the moving unit 51 determines whether shooting for all the chips 11 included in the wafer 10 is completed (Step S303). ST304). In this step ST304, when it is determined that there is an unphotographed chip 11, the moving unit 51 sets the first photographing point of the next chip 11 as a photographing target, and the sequence returns to step ST301.

  On the other hand, in step ST304, when the moving unit 51 determines that the imaging for all the chips 11 included in the wafer 10 has been completed, the sequence ends. The image of each shooting point on the chip 11 shot by the camera 3 is the same as that in FIG. Thereafter, an image inspection of the appearance of the chip 11 is performed using an image photographed by the camera 3. This image inspection is the same as the conventional one, and its description is omitted.

Next, effects of the image inspection apparatus according to the first embodiment will be described with reference to FIG. 5 shows the settling time in the conventional shooting sequence (old shooting method) shown in FIG. 7 and the settling time in the shooting sequence (new shooting method) of the first embodiment shown in FIG. .
As shown in FIG. 5, it can be seen that in the conventional imaging sequence, when the movable table 1 is moved obliquely, the movable table 1 is operated simultaneously on two axes, so that the settling time becomes longer. On the other hand, in the first embodiment, the moving direction to each photographing point is only one axis direction, and the movable table 1 is only moved in one axis direction. It is. In the example of FIG. 5, the photographing time for one chip 11 can be shortened by 500 ms. In addition, since the wafer 10 generally has about 2080 chips 11, the entire wafer 10 can reduce the photographing time by 0.5s × 2080 = 1040s (about 17 minutes).

In the above description, the case where the photographing is performed in the photographing order shown in FIG. However, the shooting order is not limited to this, and it is sufficient that the moving direction for each shooting point is in the direction of one axis. For example, the shooting order shown in FIG. 6 may be used.
4 and 6 show the case where the alignment mark 111 is at the lower left and the position of the first shooting point is at the lower left. However, the position of the alignment mark 111 is not limited to this, and the alignment mark 111 may be provided at a different position.

  4 and 6, from the viewpoint of the relationship between the performance and field of view of the camera 3 and the size of the chip 11, important inspection points on the chip 11, etc., a total of 7 points including 6 points around the chip 11 and 1 central part are shown. Shown when shooting. However, the number and position of the photographing points are not limited to this, and can be changed as appropriate.

  As described above, according to the first embodiment, since the movable table 1 is moved in the order in which the moving direction for each photographing point is the uniaxial direction, the appearance of the plurality of chips 11 included in the wafer 10 is improved. In the image inspection, the photographing time can be shortened compared with the conventional case.

  In the present invention, any constituent element of the embodiment can be modified or any constituent element of the embodiment can be omitted within the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Movable table 2 Microscope 3 Camera 4 Illumination 5 Control part 10 Wafer 11 Chip 51 Moving part 52 Image | photographing part 101 X-axis actuator 102 Y-axis actuator 111 Alignment mark

Claims (2)

A movable table on which a wafer having a plurality of chips is placed and movable independently in two axial directions;
A camera for shooting in the shooting area;
A moving unit that moves the movable table so that a plurality of photographing points set for the chip are sequentially matched to the photographing region;
A photographing unit that photographs the photographing region by the camera after the movable table is moved and settled by the moving unit for each photographing point;
The moving unit moves the movable table in the order in which the moving direction for each photographing point is a single axis direction. An image inspection method by an image inspection apparatus including a movable table on which a wafer having a plurality of chips is placed and movable independently in two axial directions, and a camera for photographing a photographing region,
The moving unit moves the movable table to sequentially match a plurality of shooting points set for the chip with the shooting region,
The photographing unit, for each of the photographing points, after the movable table is moved and settled by the moving unit, the photographing region is photographed by the camera,
The image inspection method, wherein the moving unit moves the movable table in an order in which a moving direction for each photographing point is a uniaxial direction.

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