JP7109736B2 - Auxiliary device and method - Google Patents

Description

The present invention relates to an assisting device and an assisting method for assisting alignment between the rotation axis of a table for holding a workpiece and the imaging optical axis of an imaging unit.

A dicing apparatus for cutting a workpiece such as a semiconductor wafer is well known. This dicing machine includes a blade for cutting the work, a spindle for rotating the blade at high speed, a work table for holding the work and rotating around a rotation axis, and alignment of the scheduled cutting line of the work, kerf check, etc. a microscope; Worktables and microscopes may be replaced due to wear or malfunction. After this replacement, an alignment operation (also referred to as rotation center adjustment operation) is performed to align the rotation axis of the work table and the photographing optical axis of the microscope (see Patent Document 1).

In this alignment work, the position of the rotation axis of the work table (also referred to as the rotation center position) is detected by various methods, and the photographing optical axis of the microscope is aligned with the position of this rotation axis. As a method for detecting the position of the rotating shaft of the work table, a method of visual detection is generally used.

Moreover, the above-mentioned Patent Document 1 discloses a method for automatically detecting the position of the rotating shaft of the work table. Specifically, a step of rotating the work table by a predetermined angle, a step of photographing the work table or the work with a microscope before and after the rotation of the work table, analyzing the images taken before and after the rotation of the work table, and analyzing the images taken before and after the rotation of the work table and detecting the position coordinates of the reference pattern on the front and back work table or work. Thereby, the position of the rotation axis of the work table can be automatically detected based on the position coordinates of the reference pattern before and after the rotation of the work table and the rotation angle of the work table.

JP-A-2005-93710

FIG. 20 is an explanatory diagram for explaining problems in visually detecting the position of the rotating shaft of the work table. Reference numeral 102 in FIG. 20 is a photographed image of the work holding surface (upper surface) of the work table photographed by the microscope of the dicing apparatus. Here, it is assumed that the workpiece holding surface is formed in a porous shape. Reference numeral 104 in FIG. 20 is an index representing the imaging optical axis of the microscope with an electronic line.

As indicated by symbols XA to XXC in FIG. 20, when visually detecting the position of the rotation axis of the work table, the operator rotates the work table about the rotation axis by 90° in about 0.5 seconds. Note that XXA indicates the photographed image 102 obtained before the work table starts to rotate (that is, the angle is 0°), and XXB indicates the photographed image 102 obtained during the rotation of the work table. Reference numeral XXC denotes the photographed image 102 obtained after the work table has been completely rotated (that is, at an angle of 90°).

The operator visually detects the position of the rotation axis from the photographed image 102 (see reference numeral XXB) obtained while the worktable is rotating, and stores the position. Then, after the work table is rotated (see symbol XXC), the operator moves the work table and microscope so that the previously stored position of the rotation axis (see arrow 106) coincides with the imaging optical axis indicated by index 104. Adjust the position. Thereafter, the operator repeats the above-described operations to match the rotation axis of the worktable with the photographing optical axis of the microscope.

In such a method of visually detecting the position of the rotation axis of the work table, the alignment of the rotation axis of the work table and the imaging optical axis of the microscope is performed by relying on the operator's memory, so alignment takes time. Along with this, the accuracy of alignment is lowered. Further, if the work holding surface is formed in a porous shape, the position of the rotating shaft of the work table may coincide with the hole of the porous. In this case, since the voids of the pores are dark portions in the captured image 102 , there is no marker of the rotation axis in the captured image 102 . As a result, there also arises a problem that it is difficult for the operator to judge whether the position of the rotating shaft is correct.

On the other hand, when the position of the rotation axis of the worktable is automatically detected by the method described in Patent Document 1, the reference pattern must be present within the field of view of the microscope before and after the worktable is rotated. Moreover, since a high-magnification microscope is used as the microscope to be aligned with the work table, the field of view of the microscope is very narrow. As a result, it is necessary to form the reference pattern small so that the reference pattern exists within the field of view of the microscope before and after the worktable is rotated. As a result, there arises a problem that the position detection error of the rotating shaft obtained from the detection result of the reference pattern becomes large.

FIG. 21 is an explanatory diagram for explaining a problem in automatically detecting the position of the rotation axis C of the work table 108. As shown in FIG.

As shown in FIG. 21, the light source of the microscope is a ring illumination light source 112 composed of a plurality of point light sources 110 such as LEDs (light emitting diodes), which obliquely illuminates the worktable 108. 112 is used. In this case, since the positional relationship between each point light source 110 and the reference pattern 114 changes before and after the work table 108 rotates, the shape of the reference pattern 114 in the captured image 102 changes before and after the work table 108 rotates. Therefore, it becomes difficult to detect the reference pattern 114 from the photographed images 102 before and after the work table 108 rotates with high accuracy. As a result, the detection accuracy of the position of the rotation axis C may deteriorate, and the alignment accuracy between the rotation axis C of the worktable 108 and the photographing optical axis of the microscope may deteriorate.

If the alignment accuracy between the rotation axis of the work table and the imaging optical axis of the microscope is lowered in this way, the desired pattern (alignment pattern, processing line, etc.) on the work cannot be obtained when the work table is rotated during cutting of the work. ) becomes large, and detection of this pattern may fail. For this reason, it is required to improve the alignment accuracy between the rotation axis of the work table and the imaging optical axis of the microscope.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an alignment assisting device and an assisting method for highly accurately aligning a rotation axis and a photographing optical axis.

An auxiliary device for achieving the object of the present invention comprises a rotating shaft of a table having a work holding surface for holding a work and rotating about the rotating shaft; In an auxiliary device for assisting alignment of a photographing optical axis of a photographing unit having a photographing optical axis parallel to , a rotation control unit that drives a rotation drive unit of the table to rotate the table, and a table is rotated by the rotation drive unit. While being rotated, the photographing control unit causes the photographing unit to photograph the workpiece holding surface and outputs the photographed image of the workpiece holding surface from the photographing unit; A condition setting unit that sets the arc-shaped trajectory drawn by the bright spots in the captured image as a condition under which shooting is possible, and the center of the arc in the captured image output from the imaging unit is determined as the position of the rotation axis. and a positioning unit for determining the position.

According to this auxiliary device, the position of the rotation axis can be determined with high accuracy from the position of the arc center of the trajectory in the captured image.

In the auxiliary device according to another aspect of the present invention, the photographing condition is the exposure time of the photographing unit, and the condition setting unit sets the exposure time to the case where the photographing unit photographs the workpiece held on the workpiece holding surface. Set longer than normal exposure time. Thereby, an arc-shaped trajectory can be generated in the captured image.

An auxiliary device according to another aspect of the present invention includes an illumination control unit that controls the illuminance of illumination light emitted from an illumination light source provided in an imaging unit to the workpiece holding surface or the workpiece, and the imaging conditions are exposure time and The illuminance is set by the condition setting unit to be lower than the normal illuminance of the illumination light with which the workpiece is irradiated. As a result, even when the exposure time is lengthened, the captured image is prevented from being overexposed.

In the auxiliary device according to another aspect of the present invention, the rotation control unit maintains the angular velocity of the table at a constant speed within a predetermined period when the table is rotated by the rotation driving unit, and the condition setting unit The start timing and end timing of the exposure time are set within the period.

In the auxiliary device according to another aspect of the present invention, the imaging unit is provided with a ring illumination light source having a plurality of light sources arranged at equal angular pitches along the circumferential direction centered on the imaging optical axis. where θp is the equal angular pitch, θc is the rotation angle of the table, and n is an arbitrary natural number, θc≧θp or θc=n×θp is satisfied. This makes it easier to recognize the trajectory in the captured image.

In the auxiliary device according to another aspect of the present invention, a display control unit for displaying a photographed image output from the photographing unit on a display unit, and specifying the position of the arc center of the trajectory in the photographed image displayed on the display unit. an operation unit that receives an input of a designation operation to be performed, and a position determination unit that determines the position of the rotation axis based on the designation operation input to the operation unit. This allows manual determination of the position of the axis of rotation in the captured image.

In the auxiliary device according to another aspect of the present invention, to match the photographic optical axis with the rotational axis based on the known position of the photographic optical axis in the photographic image and the position of the rotational axis determined by the position determining unit. and a correction position calculator for calculating the correction position of the . Thereby, the position of the photographing optical axis and the position of the rotation axis can be matched.

In the auxiliary device according to another aspect of the present invention, the position determination unit analyzes the photographed image output from the photographing unit and detects the trajectory in the photographed image, and the trajectory is detected by the trajectory detection unit. a position calculation unit that calculates the position of the rotating shaft based on the result. Thereby, the position of the rotation axis in the captured image can be automatically determined. Moreover, even when the rotation axis exists outside the captured image, the position of the rotation axis can be determined.

In the auxiliary device according to another aspect of the present invention, the corrected position of the rotation axis that matches the imaging optical axis based on the known position of the imaging optical axis in the captured image and the position of the rotation axis determined by the position determining unit. and a relative movement unit that relatively moves the photographing unit and the table in the direction perpendicular to the rotation axis based on the calculation result of the correction position by the correction position calculation unit. The rotation control unit, the photography control unit, A repeat control unit that repeatedly operates the position determination unit and the movement control unit. As a result, it is possible to automatically align the photographing optical axis and the rotation axis.

In the auxiliary device according to another aspect of the present invention, the photographing control section causes the photographing section to photograph the porous workpiece holding surface rotated about the rotation axis by the rotation driving section.

An auxiliary method for achieving the object of the present invention is to provide a rotating shaft of a table having a work holding surface for holding a work and rotating about the rotating shaft, and In an assisting method for assisting alignment of a photographing optical axis of a photographing unit having a photographing optical axis parallel to , a rotation control step of rotating a table; a photographing control step of causing the unit to photograph the workpiece holding surface and outputting a photographed image of the workpiece holding surface from the photographing unit; a condition setting step of setting the arc-shaped trajectory drawn by the image captureable condition; and a position determination step of determining the arc center of the trajectory in the captured image output from the imaging unit as the position of the rotation axis. .

According to the present invention, it is possible to align the rotation axis and the photographing optical axis with high accuracy.

1 is a perspective view of a dicing apparatus according to a first embodiment; FIG. It is an external appearance perspective view of a processing part. 1 is a schematic diagram of a spindle, an imaging unit, and a worktable; FIG. 1 is a schematic diagram of a high power microscope and a low power microscope; FIG. 3 is a functional block diagram of an integrated control section of the dicing apparatus of the first embodiment; FIG. It is the description which showed an example of the picked-up image of a workpiece|work holding surface. FIG. 5 is an explanatory diagram for explaining setting of start timing and end timing of exposure time; FIG. 10 is an explanatory diagram for explaining setting of a rotation angle when the light source used is a ring illumination light source; FIG. 4 is an explanatory diagram showing an example of an auxiliary screen displayed on the display unit; 4 is a flow chart showing the flow of alignment work between the photographing optical axis of the high-magnification microscope and the rotation axis of the work table in the dicing apparatus of the first embodiment; FIG. 11 is a functional block diagram of an integrated control section of the dicing apparatus of the second embodiment; FIG. 10 is an explanatory diagram for explaining a trajectory detection process by a trajectory detection unit; FIG. 4 is an explanatory diagram for explaining a first calculation method of the position of the rotating shaft by the position calculator; FIG. 10 is an explanatory diagram for explaining a second calculation method of the position of the rotating shaft by the position calculator; FIG. 10 is an explanatory diagram for explaining a third calculation method of the position of the rotating shaft by the position calculator; FIG. 10 is an explanatory diagram for explaining a fourth calculation method of the position of the rotating shaft by the position calculator; FIG. 7 is an explanatory diagram for explaining the effect of calculating the position of the rotating shaft by the first to fourth calculation methods; 9 is a flow chart showing the flow of alignment work between the photographing optical axis of the high-magnification microscope and the rotation axis of the work table in the dicing apparatus of the second embodiment. 10 is a flow chart showing the flow of alignment work between the photographing optical axis of the high-magnification microscope and the rotation axis of the work table in the dicing apparatus of the third embodiment. FIG. 10 is an explanatory diagram for explaining a problem in visually detecting the position of the rotating shaft of the work table; FIG. 10 is an explanatory diagram for explaining a problem in automatically detecting the position of the rotating shaft of the work table;

[Configuration of the dicing apparatus of the first embodiment]
FIG. 1 is a perspective view of a dicing apparatus 10 for cutting a work W such as a semiconductor wafer. In addition, the XYZ axes in the drawing are mutually orthogonal axes, the XY axis is an axis parallel to the horizontal direction, and the Z axis is an axis orthogonal to the horizontal direction.

The dicing apparatus 10 includes a load port 12 , a transport mechanism 14 , a processing section 16 and a cleaning section 18 . A cassette containing a large number of works W mounted on the frame F is placed on the load port 12 . The transport mechanism 14 transports the work W. As shown in FIG. The processing unit 16 performs dicing processing of the work W. As shown in FIG. The cleaning unit 18 spin-cleans the workpiece W that has been cut. Further, inside the housing 10A of the dicing machine 10, an integrated control section 60 (see FIG. 5) and the like for controlling the operation of each section of the dicing machine 10 are provided.

An unprocessed work W stored in a cassette mounted on a load port 12 is transported to a processing section 16 by a transport mechanism 14, and is cut or grooved in the processing section 16 so as to be divided into individual chips. Cutting such as processing is applied. The workpiece W processed by the processing unit 16 is transported to the cleaning unit 18 by the transport mechanism 14, and after being cleaned by the cleaning unit 18, is transported to the load port 12 by the transport mechanism 14 and stored in the cassette.

FIG. 2 is an external perspective view of the processing portion 16. As shown in FIG. As shown in FIG. 2 and FIG. 1 already described, the processing unit 16 includes a pair of blades 21 and a blade cover (not shown), a pair of spindles 22, a pair of imaging units 23, and a work table for holding a work. 31 (corresponding to the table of the present invention). A pair of blades 21 are arranged opposite to each other in the Y-axis direction, and are held by a spindle 22 so as to be rotatable about a blade rotation axis parallel to the Y-axis direction. A pair of spindles 22 incorporates a high-frequency motor and rotates the blades 21 at high speed around the blade rotation axis.

One photographing unit 23 is provided near each spindle 22 to photograph the surface of the work W and the tip of the blade 21 . In FIG. 2, in order to prevent complication of the drawing, only the photographing unit 23 provided near one of the two spindles 22 is illustrated, and the photographing unit 23 provided near the other is illustrated. are omitted.

Each spindle 22 and each photographing unit 23 is held movably in the Y-axis direction and the Z-axis direction via a Y carriage 43 and a Z carriage 44, which will be described later.

The work table 31 sucks and holds the work W on a work holding surface 31a, which is the upper surface thereof. In order to hold the work W, the work holding surface 31a is formed porous as shown in FIG. The work table 31 is held movably in the X-axis direction by an X carriage 36, which will be described later, and rotatably around a rotation axis C by a rotating unit 37, which will be described later.

The processing section 16 is provided with an X base 32 , an X guide 34 , an X drive section 35 , an X carriage 36 and a rotation unit 37 . The X base 32 has a flat plate shape extending in the X-axis direction, and an X guide 34 is provided on the upper surface in the Z-axis direction. The X guide 34 has a shape extending in the X-axis direction and guides the X carriage 36 along the X-axis direction. The X drive unit 35 uses, for example, a linear motor or the like, and moves (drives) the X carriage 36 in the X-axis direction along the X guide 34 .

The rotating unit 37 is provided on the upper surface of the X carriage 36 . A work table 31 is provided on the upper surface of the rotating unit 37 . The rotation unit 37 rotates the work table 31 about its rotation axis C in the θ direction by being rotationally driven by a rotation drive section 38 (see FIG. 5) composed of a motor, gears, and the like.

The work W transported from the load port 12 by the transport mechanism 14 is held by suction on the work table 31 , thereby moving and rotating integrally with the work table 31 . As a result, rotation of the work W in the .theta. direction during alignment prior to cutting, cutting feed of the work W in the X direction during cutting of the work W, and the like are performed via the work table 31 and the like.

The processing unit 16 is also provided with a Y base 41 , a Y guide 42 , a pair of Y carriages 43 , and a pair of Z carriages 44 . The Y base 41 has a portal shape straddling the X base 32 in the Y-axis direction. A Y guide 42 is provided on the side surface of the Y base 41 in the X-axis direction. The Y guide 42 has a shape extending in the Y-axis direction, and guides the pair of Y carriages 43 along the Y-axis direction. The pair of Y carriages 43 are independently driven along the Y guide 42 by a Y driving section 46 (see FIG. 5) composed of a stepping motor, a ball screw, and the like.

Each of the pair of Y carriages 43 is provided with a Z carriage 44 movably in the Z-axis direction via a Z drive section 48 (see FIG. 5) composed of a stepping motor or the like. Each Z carriage 44 is attached with the already described spindle 22 . As a result, when cutting the work W, the blade 21 is index-fed in the Y-axis direction and cut-fed in the Z-axis direction with respect to the work W sucked and held by the work table 31 .

Although two sets of the spindle 22, the imaging unit 23, the Y carriage 43, and the Z carriage 44 are provided facing each other on the left and right, they have the same configuration and action, so only one (right side) will be focused on below. and explain.

FIG. 3 is a schematic diagram of the spindle 22, the imaging unit 23, and the work table 31. As shown in FIG. As shown in FIG. 3 and FIG. 2 already described, the imaging unit 23 is fixed to the Z carriage 44 together with the spindle 22 . As a result, the photographing unit 23 is fixed in position relative to the spindle 22 (blade 21 ), and is moved together with the spindle 22 in the Y and Z directions by driving the Y carriage 43 and Z carriage 44 .

The imaging unit 23 includes a high-magnification microscope 23A having an imaging optical axis OA parallel to the Z-axis direction, and a low-magnification microscope 23B having an imaging optical axis OB parallel to the Z-axis direction. Each microscope 23A, 23B photographs the surface of the work W when the work W is cut. The imaging magnification of the high-magnification microscope 23A is set higher than the imaging magnification of the low-magnification microscope 23B. In other words, the imaging magnification of the low-magnification microscope 23B is set lower than the imaging magnification of the high-magnification microscope 23A. For example, the high-magnification microscope 23A has an 8-fold imaging magnification, and the low-magnification microscope 23B has a 1-fold imaging magnification. In addition, the photographing by the high-magnification microscope 23A and the photographing by the low-magnification microscope 23B are selectively executed.

FIG. 4 is a schematic diagram of the high-magnification microscope 23A and the low-magnification microscope 23B. As shown in FIG. 4, each of the microscopes 23A and 23B has basically the same configuration except that the imaging magnification is different. 53 and.

The epi-illumination light source 50 emits illumination light toward the half mirror 55 of the imaging optical system 51 . The imaging optical system 51 has a half mirror 55 and an objective lens 56 along the imaging optical axes OA and OB. The half mirror 55 is arranged between the imaging element 53 and the objective lens 56 and reflects the illumination light incident from the epi-illumination light source 50 toward the objective lens 56 . In addition, the half mirror 55 transmits the reflected light of the illumination light incident from the objective lens 56 as it is, and makes it enter the imaging device 53 .

The objective lens 56 causes the illumination light incident from the half mirror 55 to enter the work holding surface 31a, which is the upper surface of the work table 31, or the upper surface of the work W set on the work holding surface 31a. As a result, illumination light from the epi-illumination light source 50 is incident on the workpiece holding surface 31a or the upper surface of the workpiece W coaxially with the photographing optical axes OA and OB.

The ring illumination light source 52 has a plurality of light sources 52a arranged at an equal angular pitch θp (see FIG. 8) along the circumferential direction around the imaging optical axes OA and OB. The ring illumination light source 52 performs oblique illumination by illuminating the workpiece holding surface 31a or the upper surface of the workpiece W from each light source 52a in an oblique direction (an oblique direction with respect to the photographing optical axes OA and OB). As a result, part of the illumination light incident on the work holding surface 31 a or the upper surface of the work W from each light source 52 a is reflected toward the objective lens 56 .

Reflected light of the illumination light incident on the objective lens 56 passes through the half mirror 55 and enters the light receiving surface of the imaging element 53 . The imaging device 53 is, for example, a CMOS (complementary metal oxide semiconductor) type or a CCD (charge coupled device) type. The image data of the captured image 80 is emitted toward the general control section 60 (see FIG. 5), which will be described later.

When photographing (observing) with the microscopes 23A and 23B, the epi-illumination light source 50 and the ring illumination light source 52 are selectively used according to the surface condition of the object to be photographed. Specifically, the epi-illumination light source 50 is used when the surface condition of the object to be photographed is smooth (including substantially smooth), and the ring illumination light source 52 is used when the surface condition of the object to be photographed is non-smooth. be. Note that the proper use of the epi-illumination light source 50 and the ring illumination light source 52 is a known technology (for example, Japanese Patent Application Laid-Open No. 2017-69579), so detailed description is omitted here.

Further, both the epi-illumination light source 50 and the ring illumination light source 52 can be used for photographing the porous workpiece holding surface 31a in the positioning work described later, and either the epi-illumination light source 50 or the ring illumination light source 52 can be selected. used for purposes.

Returning to FIG. 3, since both the photographing unit 23 and the spindle 22 are fixed to the Z carriage 44, the position coordinates (x, y) of the photographing optical axis OA of the high-magnification microscope 23A or the photographing optical axis of the low-magnification microscope 23B From one of the position coordinates (x, y) of the OB, the position coordinates (x, y) of the other and the position coordinates (x, y) of the lowest point of the cutting edge of the blade 21 can be detected. Note that the imaging optical axes OA and OB include the center of the field of view of the high-magnification microscope 23A and the low-magnification microscope 23B (centers in the X-axis direction and the Y-axis direction).

In the dicing apparatus 10, when at least one of the photographing unit 23 (high-magnification microscope 23A, etc.) and the work table 31 is replaced, or at regular timing, the direction perpendicular to the rotation axis C, that is, the X-axis direction and the Y-axis direction Alignment operation of the photographing optical axis OA of the high-magnification microscope 23A and the rotation axis C of the work table 31 in each direction is executed. This positioning work is performed on the rotation center G which is the intersection of the movement line of the photographing optical axis OA movable in the Y-axis direction and the movement line of the rotation axis C movable in the X-axis direction. In other words, the positioning work is performed so that the photographing optical axis OA and the rotation axis C are aligned on the rotation center G. FIG.

Therefore, the dicing machine 10 has an auxiliary function for assisting the alignment work by the operator. Therefore, the dicing machine 10 functions as an auxiliary device of the present invention.

Although details will be described later, instead of aligning the photographing optical axis OA (high-magnification microscope 23A) and the rotation axis C, the photographing optical axis OB (low-magnification microscope 23B) and the rotation axis C are aligned. sometimes work.

FIG. 5 is a functional block diagram of the integrated control section 60 of the dicing apparatus 10 of the first embodiment. As shown in FIG. 5, the integrated control unit 60 includes one or more processors (eg, CPU (Central Processing Unit), FPGA (field-programmable gate array), etc.). It is composed of a memory and the like, and controls the operation of each part of the dicing apparatus 10 in an integrated manner. In FIG. 5, among a plurality of functions of the integrated control unit 60, functions related to assisting the alignment work are illustrated, and functions related to other controls of the dicing apparatus 10 such as cutting of the workpiece W are known. Since it is a technique, illustration is omitted.

In addition to the photographing unit 23 (the high-magnification microscope 23A and the low-magnification microscope 23B), the X driving unit 35, the rotation driving unit 38, the Y driving unit 46, and the Z driving unit 48, the integrated control unit 60 also includes an operation unit. A unit 62, a storage unit 64, a display unit 66, and the like are connected.

The operation unit 62 uses a keyboard, a mouse, an operation panel, operation buttons, and the like, and receives various operations by the operator. Operations related to alignment work include, for example, a work start operation, a relative movement operation, a microscope selection operation, a light source selection operation, a condition setting operation, an index movement operation, and a designation operation.

The relative movement operation is an operation for moving the photographing unit 23 in the Y-axis direction and moving the worktable 31 in the X-axis direction, that is, for performing relative movement between the photographing unit 23 and the worktable 31 . The work start operation is a start operation for starting alignment work.

The microscope selection operation is a selection operation for selecting one of the high-magnification microscope 23A and the low-magnification microscope 23B to be used for photographing the workpiece holding surface 31a. Note that the high-magnification microscope 23A is selected in advance in the alignment work.

The light source selection operation is a selection operation for selecting a light source to be used for illuminating the workpiece holding surface 31a from among the epi-illumination light source 50 and the ring illumination light source 52. FIG. Hereinafter, the light source selected by the light source selection operation will be referred to as a "use light source".

The index movement operation, which will be described in detail later, is a movement operation for moving the position of the movement index 88 within the auxiliary screen 68 displayed on the display unit 66 . The specifying operation, which will be described later in detail, is an operation for specifying the position of the rotation axis C within the auxiliary screen 68 .

The storage unit 64 stores a control program (not shown) for the dicing machine 10 . Further, the storage unit 64 stores the position coordinates (x, y) of the photographing unit 23 and the work table 31 after completion of alignment. Further, the storage unit 64 stores relative position information (not shown) indicating the relative position of one of the imaging optical axis OA of the high-magnification microscope 23A and the imaging optical axis OB of the low-magnification microscope 23B with respect to the other. .

The display unit 66 is, for example, various known monitors such as a liquid crystal display. This display unit 66 displays an auxiliary screen 68 for assisting the operator in the alignment work under the control of the integrated control unit 60 during the alignment work of the first embodiment.

By executing a control program (not shown) stored in the storage unit 64, the overall control unit 60 performs a movement control unit 69, a rotation control unit 70, an imaging control unit 71, an illumination control unit 72, It functions as a condition setting section 73 , an image acquisition section 74 , a display control section 75 , a position determination section 76 and a correction position calculation section 77 . The operation of each part in the alignment work between the photographing optical axis OA and the rotation axis C will be described below.

The movement control unit 69 drives the X driving unit 35 to move the X carriage 36 in the X-axis direction, and drives the Y driving unit 46 to move the Y carriage 43 in the Y-axis direction. The magnification microscope 23A and the work table 31 are relatively moved in the X-axis direction and the Y-axis direction. During the alignment work, the movement control section 69 drives the X drive section 35 and the Y drive section 46 in response to the operator's work start operation on the operation section 62 to move the high-magnification microscope 23A and the work table 31 together. Each is moved to the center of rotation G (see FIG. 3).

The rotation control section 70 controls rotation of the work table 31 via the rotation unit 37 by driving the rotation drive section 38 . When both the high-magnification microscope 23A and the work table 31 have been moved to the rotation center G during the alignment work, the rotation control unit 70 drives the rotation driving unit 38 to rotate the rotation unit 37 at a constant rotation angle θc. only rotate. As a result, the work table 31 is rotated about the rotation axis C by the rotation angle θc. Note that the rotation angle θc is determined by a condition setting unit 73, which will be described later.

Further, the rotation control unit 70 maintains the angular velocity ω0 (see FIG. 7) when rotating the work table 31 at a predetermined constant velocity. As a result, as shown in FIG. 7, which will be described later, the work table 31 is rotated at a constant speed during a constant velocity period excluding the start of rotation (acceleration period) and the end of rotation (deceleration period).

The imaging control unit 71 controls imaging by the imaging unit 23 . When the work table 31 starts to rotate during the alignment work, the photographing control unit 71 causes the high magnification microscope 23A of the photographing unit 23 to photograph the work holding surface 31a of the rotating work table 31 . At this time, the photographing control unit 71 performs so-called long exposure photographing of the workpiece holding surface 31a according to the exposure time set by the condition setting unit 73, which will be described later.

The illumination control unit 72 controls illumination by the epi-illumination light source 50 and the ring illumination light source 52 of the photographing unit 23 (each of the microscopes 23A and 23B). The illumination control unit 72 irradiates the work holding surface 31a with illumination light from the light source of the high-magnification microscope 23A selected by the light source selection operation described above in response to the work start operation described above. At this time, the lighting control section 72 controls the illuminance of illumination light emitted from the light source to the workpiece holding surface 31a according to the illuminance set by the condition setting section 73, which will be described later.

The condition setting unit 73 sends the captured image of the work holding surface 31a to the rotation control unit 70, the imaging control unit 71, and the illumination control unit 72 in response to the operator's operation to start the operation on the operation unit 62 during the alignment work. 80 shooting conditions are set. This photographing condition is a condition in which a trajectory 82 (see FIG. 6) drawn by a bright spot portion 83 in a photographed image 80 rotating around the rotation axis C can be photographed. The photographing conditions include the exposure time (period) for photographing with the high-magnification microscope 23A, the illuminance of the illumination light emitted from the light source to the work holding surface 31a, and the rotation angle θc of the work table 31. included.

First, the setting of the exposure time of the high-magnification microscope 23A by the condition setting unit 73 will be described.

As indicated by XXA in FIG. 20, the workpiece holding surface 31a is porous. Therefore, the photographed image 80 of the workpiece holding surface 31a becomes a porous pattern image including randomly arranged bright point portions 83 and dark point portions 84 as shown in FIG. 6 which will be described later. Therefore, during the alignment work, by rotating the work table 31 during imaging with the high-magnification microscope 23A, the bright spot portion 83 in the shot image 80 rotates about the rotation axis C, and the bright spot portion 83 draws an arc-shaped trajectory 82 (see FIG. 6) centered on the rotation axis C. As shown in FIG. Therefore, by performing long-time exposure photographing of the work holding surface 31a with the high-magnification microscope 23A while the work table 31 is rotating, the trajectory 82 having the rotation axis C as the center of the arc can be photographed.

FIG. 6 is an explanation showing an example of a photographed image 80 of the workpiece holding surface 31a. Reference numeral 6A in FIG. 6 denotes a photographed image 80 of the workpiece holding surface 31a photographed by the high-magnification microscope 23A when the exposure time of the high-magnification microscope 23A is set to the normal exposure time (for example, 35 msec). Here, the normal exposure time is the exposure time for dicing the work W, that is, for photographing the work W held on the work holding surface 31a with the high-magnification microscope 23A. Reference numeral 6B in FIG. 6 denotes a photographed image 80 of the workpiece holding surface 31a photographed by the high-magnification microscope 23A when the exposure time of the high-magnification microscope 23A is set longer than the normal exposure time (for example, 600 msec). .

As shown in FIG. 6, by setting the exposure time of the high-magnification microscope 23A to be longer than the normal exposure time, an arcuate shape formed by a bright spot portion 83 rotating around the rotation axis C is captured in the photographed image 80. A trajectory 82 (including substantially arc-shaped and substantially circular) is generated. Since the position of the arc center of the trajectory 82 in the captured image 80 corresponds to the position of the rotation axis C, the position of the rotation axis C can be determined from the trajectory 82 .

The condition setting unit 73 sets the length of the exposure time and the start timing of the exposure time as shown in FIG. and setting ST and end timing ET. Specifically, the length of the exposure time is set according to the angular velocity (rotational speed) of the work table 31 so that the locus 82 can be photographed.

FIG. 7 is an explanatory diagram for explaining the setting of the start timing ST and the end timing ET of the exposure time. Note that the horizontal axis in FIG. 7 is time (t), and the vertical axis is the angular velocity (ω0) of the work table 31 (work holding surface 31a).

As shown in FIG. 7, the angular velocity ω0 of the work table 31 is maintained at a constant velocity within a predetermined constant velocity period. In this embodiment, both the start timing ST and the end timing ET of the exposure time are set within the constant velocity period. Therefore, during the alignment work, long-time exposure photographing of the high-magnification microscope 23A is performed only during the constant velocity period. This prevents variations in luminance and shape (diameter, etc.) from the start end to the end of the locus 82 due to changes in the angular velocity ω0 during long-exposure photography. As a result, the position of the center of the arc, that is, the position of the rotation axis C can be determined from the trajectory 82 more accurately.

Next, setting of the illuminance of illumination light by the condition setting unit 73 will be described. As described above, when long-exposure photography of the workpiece holding surface 31a is performed with the high-magnification microscope 23A, the exposure amount becomes excessive, and the photographed image 80 may have so-called overexposure. In this case, it becomes difficult to distinguish the trajectory 82 in the captured image 80 .

Therefore, the condition setting unit 73 sets the illumination control unit 72 for the illuminance of the illumination light emitted from the light source to be used to the workpiece holding surface 31a (hereinafter simply referred to as the illuminance of the light source to be used). As a result, the illuminance (amount of illumination light) during the alignment work is set lower than the normal illuminance. Here, the normal illuminance is the illuminance of the illumination light that illuminates the work W from the light source used to illuminate the work W on the work holding surface 31a when the work W is diced. Specifically, the illuminance during the alignment work is set to a value that allows the locus 82 in the captured image 80 to be determined (a value that prevents the captured image 80 from being overexposed).

Next, setting of the rotation angle θc of the work table 31 by the condition setting unit 73 will be described. The condition setting unit 73 sets the rotation angle θc of the work table 31 to the rotation control unit 70 . Specifically, when the incident light source 50 is used as the light source, the condition setting unit 73 sets the rotation angle θc during the alignment work to an arbitrary angle (for example, 90°).

FIG. 8 is an explanatory diagram for explaining the setting of the rotation angle θc when the ring illumination light source 52 is used as the light source. As shown in FIG. 8, when the light sources 52a of the ring illumination light source 52 are arranged at an equal angular pitch θp along the circumferential direction around the photographing optical axis OA, the condition setting unit 73 performs the alignment work. The rotation angle θc at time is set to "θc≧θp" or "θc=n (any natural number)×θp".

When the rotation angle θc is “θc<θp”, depending on the positional relationship between the bright spot 83 and each light source 52a, the brightness from the start end to the end of the locus 82 may be low, and the locus 82 in the photographed image 80 may not be discriminated. It may become difficult. On the other hand, when the rotation angle θc satisfies “θc≧θp”, the bright spot portion 83 is at least once near the light source 52a (a line connecting the light source 52a and the photographing optical axis OA) during the rotation of the work table 31. above). As a result, the brightness of the bright spot portion 83 increases near the light source 52a, and the locus 82 in the captured image 80 becomes easier to recognize.

When the rotation angle θc is “θc=n×θp”, the relative positional relationship of each light source 52a with respect to the bright spot portion 83 does not change before and after the work table 31 rotates. Both ends have approximately the same brightness. This makes it easier to recognize the locus 82 even when the luminance is low in the midway portion between the start and end of the locus 82 .

In this manner, the condition setting unit 73 sets the exposure time of the high-magnification microscope 23A, the illuminance of the light source used, and the rotation angle θc of the work table 31 to ensure that the trajectory 82 is formed in the photographed image 80. to occur.

Returning to FIG. 5 , the image acquisition section 74 is an image input interface connected to the photographing section 23 . The image acquisition unit 74 acquires image data of the photographed image 80 including the trajectory 82 from the high-magnification microscope 23A and outputs this image data to the display control unit 75 during alignment work.

The display control section 75 controls image display on the display section 66 . During the alignment work, the display control section 75 generates an auxiliary screen 68 for assisting the operator in the alignment work based on the image data of the photographed image 80 input from the image acquisition section 74, and The auxiliary screen 68 is displayed on the display unit 66 .

FIG. 9 is an explanatory diagram showing an example of the auxiliary screen 68 displayed on the display unit 66. As shown in FIG. As shown in FIG. 9 and FIG. 5 already described, the auxiliary screen 68 displayed on the display unit 66 by the display control unit 75 includes a photographed image 80 of the work holding surface 31a and an optical axis index 86 drawn with electronic lines. and movement indicator 88 .

The optical axis index 86 is a cross-shaped mark that indicates the position of the imaging optical axis OA of the high-magnification microscope 23A within the auxiliary screen 68 (captured image 80). Here, among the pixels of the image sensor 53 of the high-magnification microscope 23A, the specific pixel that coincides with the photographic optical axis OA is already known. can be easily determined. Therefore, the display control unit 75 superimposes the optical axis index 86 on the position corresponding to the photographing optical axis OA in the photographed image 80 . The shape of the optical axis index 86 is not limited to a cross shape, and can take any shape that indicates the position of the photographing optical axis OA.

The movement index 88 has a shape obtained by synthesizing, for example, a cross-shaped mark and a mark arranged concentrically at the center thereof. The display control unit 75 changes the display position of the movement indicator 88 within the auxiliary screen 68 according to the operator's operation on the operation unit 62 . This allows the operator to arbitrarily change the position of the movement index 88 within the auxiliary screen 68 .

Specifically, after the auxiliary screen 68 is displayed, the operation unit 62 receives an input of the index movement operation by the operator. This index movement operation is an operation for moving the movement index 88 within the auxiliary screen 68 so that the center of the movement index 88 coincides with the position of the rotation axis C. FIG.

As described above, one or more trajectories 82 are generated in the captured image 80 on the auxiliary screen 68 . Since the position of the arc center of all the trajectories 82 corresponds to the position of the rotation axis C, the operator determines the position of the arc center of all the trajectories 82 from the photographed image 80 in the auxiliary screen 68, and moves the movement index to this position. The operation unit 62 is operated to move the index so that the centers of 88 are aligned. As a result, the center position of the movement index 88 coincides with the position of the rotation axis C within the auxiliary screen 68 .

Further, the operation unit 62 receives an input of a designation operation by the operator after completion of the target moving operation described above. This specifying operation is an operation of specifying the center position of the movement index 88 as the position of the arc center of each trajectory 82, that is, the position of the rotation axis C. FIG.

Note that when the arc center (rotational axis C) of the trajectory 82 does not exist in the captured image 80 of the auxiliary screen 68, the operation unit 62 accepts input of relative movement operation by the operator. The relative movement operation in this case is an operation of relatively moving the imaging unit 23 and the work table 31 so that the arc center of the trajectory 82 moves within the auxiliary screen 68 . Accordingly, the movement control unit 69 drives the X driving unit 35 and the Y driving unit 46 to relatively move the high-power microscope 23A and the work table 31 in the X-axis direction and the Y-axis direction. The arc center of locus 82 is moved inward. As a result, the above-described eye target movement operation and designation operation become possible.

The position determination unit 76 acquires the position coordinates of the center position of the movement index 88 in the auxiliary screen 68 via the display control unit 75 when a designation operation is input through the operation unit 62, and rotates the position coordinates. Determine the position of axis C. Then, the position determination unit 76 outputs the coordinates of the center position of the movement index 88 to the correction position calculation unit 77 as rotation axis position information indicating the position of the rotation axis C. FIG.

Based on the rotation axis position information of the rotation axis C within the auxiliary screen 68 input from the position determination unit 76 and the known position information of the photographing optical axis OA within the auxiliary screen 68, the correction position calculation unit 77 A correction position for matching the imaging optical axis OA and the rotation axis C, more specifically, a correction position for the rotation axis C for matching the imaging optical axis OA is calculated.

For example, the correction position calculation unit 77 first calculates the amount of positional deviation (the number of pixels) between the position of the rotation axis C based on the rotation axis position information and the position of the photographing optical axis OA in the X-axis direction and the Y-axis direction. do. For example, when the imaging magnification of the high-magnification microscope 23A is 8 times, one pixel of the captured image 80 corresponds to a distance of 7.4 μm. A positional deviation amount (distance) in the X-axis direction and the Y-axis direction is calculated from the deviation amount (the number of pixels). Thereby, the corrected position calculator 77 can calculate the corrected position of the rotation axis C on the rotation center G. FIG. The corrected position of the rotation axis C is stored in the storage section 64 by the corrected position calculation section 77 .

[Action of the dicing apparatus of the first embodiment]
FIG. 10 is a flow chart showing the flow of alignment work (corresponding to the auxiliary method of the present invention) between the imaging optical axis OA of the high-magnification microscope 23A and the rotation axis C of the work table 31 in the dicing apparatus 10 of the first embodiment. be. As shown in FIG. 10, the operator starts alignment work when replacing at least one of the imaging unit 23 and the work table 31, or at regular timings.

When the operator inputs an operation start operation for alignment work to the operation unit 62 (step S1), the movement control unit 69 drives the X drive unit 35 and the Y drive unit 46 to move the high magnification microscope 23A and the work table. 31 are moved to the center of rotation G (step S2).

Further, in response to the work start operation described above, the condition setting unit 73 causes the rotation control unit 70, the photography control unit 71, and the illumination control unit 72 to set the photography conditions for the photographed image 80 of the workpiece holding surface 31a. (Step S3, corresponding to the condition setting step of the present invention). Thereby, the exposure time of the high magnification microscope 23A, the start timing ST, the end timing ET, the illuminance of the light source used, and the rotation angle θc of the work table 31 are set respectively.

When both the high-magnification microscope 23A and the work table 31 are moved to the rotation center G, the rotation control unit 70 drives the rotation driving unit 38 to rotate the work table 31 by the previously set rotation angle θc. (Step S4 corresponds to the rotation control step of the present invention).

Further, when the work table 31 starts to rotate, the photographing control unit 71 controls the high-power microscope 23A during this rotation so that a In the constant-velocity period, the high-magnification microscope 23A is caused to perform long-time exposure photographing of the workpiece holding surface 31a (step S4, corresponding to the photographing control step of the present invention). As a result, a captured image 80 including the trajectory 82 is obtained. Further, by performing long-time exposure photography within the constant velocity period, variation in brightness and shape from the start end to the end of the locus 82 can be suppressed.

Image data of the captured image 80 captured by the high-magnification microscope 23A is output from the high-magnification microscope 23A to the display control unit 75 via the image acquisition unit 74 . As a result, the display control unit 75 generates the auxiliary screen 68 as shown in FIG. 9 based on the image data of the captured image 80, and causes the display unit 66 to display the auxiliary screen 68 (step S5). ).

When the auxiliary screen 68 is displayed on the display unit 66, the operator confirms the trajectories 82 in the photographed image 80 on the auxiliary screen 68 and determines the position of the arc center of all the trajectories 82, that is, the position of the rotation axis C. discriminate. Then, if the rotation axis C does not exist within the auxiliary screen 68, the operator performs a relative movement operation on the operation unit 62 (NO in step S6).

In response to this relative movement operation, the movement control section 69 drives the X drive section 35 and the Y drive section 46 to relatively move the high-magnification microscope 23A and the work table 31 in the X-axis direction and the Y-axis direction ( step S7). As a result, the rotation axis C (arc center) moves within the field of view of the high-magnification microscope 23A. As a result, the rotational axis C of the trajectory 82 is moved within the auxiliary screen 68 through steps S4 and S5 described above.

If the rotation axis C exists within the captured image 80 on the auxiliary screen 68 (YES in step S6), the operator performs an index movement operation on the operation unit 62 (step S8). In response to this index moving operation, the display control unit 75 moves the position of the movement index 88 within the auxiliary screen 68 so that the center position of the movement index 88 coincides with the position of the rotation axis C. FIG.

When the center position of the movement index 88 matches the position of the rotation axis C, the operator inputs a designation operation to the operation section 62 (step S9). Upon receiving the input of this specifying operation, the position determination unit 76 determines the center position of the movement index 88 in the auxiliary screen 68 as the position of the rotation axis C, and corrects the rotation axis position information indicating the position of the rotation axis C. Output to the position calculator 77 (step S10, corresponding to the position determination step of the present invention).

Next, the correction position calculation unit 77 calculates the correction position of the rotation axis C that matches the photographic optical axis OA based on the rotational axis position information input from the position determination unit 76 and the known position information of the photographic optical axis OA. Calculation is performed, and the calculation result is stored in the storage unit 64 . As a result, when the high-magnification microscope 23A and the work table 31 are respectively moved to the rotation center G again, the position of the rotation axis C is corrected based on the correction position in the storage unit 64. Axis OA and rotation axis C can be coincident.

In the above-described first embodiment, if NO in step S6, relative movement is performed to move the rotation axis C within the auxiliary screen 68 in step S7. Alignment (rough adjustment) between the imaging optical axis OB of the magnification microscope 23B and the rotation axis C may be performed. In this case, the operator performs a microscope selection operation on the operation unit 62 to switch to imaging of the workpiece holding surface 31a by the low-magnification microscope 23B.

Then, the process from step S1 to step S11 in FIG. 10 is repeatedly executed to determine the correction position (approximate correction position) of the rotation axis C that matches the imaging optical axis OB of the low-magnification microscope 23B. Next, based on this corrected position, the movement control section 69 drives the X drive section 35 and the Y drive section 46 to correct the position of the rotation axis C. FIG.

At this time, the positional relationship between the imaging optical axis OA of the high-magnification microscope 23A and the imaging optical axis OB of the low-magnification microscope 23B is constant. Therefore, the movement control unit 69 stores relative position information (not shown) indicating the relative position of one of the imaging optical axis OA of the high-magnification microscope 23A and the imaging optical axis OB of the low-magnification microscope 23B with respect to the other. etc. Next, the movement control section 69 drives the X driving section 35 and the Y driving section 46 based on this relative position information to change the position of the photographing optical axis OA and the position of the photographing optical axis OB on the rotation axis C. Replace.

Next, the operator performs a microscope selection operation on the operation section 62 to switch to photographing of the workpiece holding surface 31a by the high-magnification microscope 23A. Since the alignment has already been performed once, the rotation axis C can be reliably moved within the field of view of the high-magnification microscope 23A. Thereafter, according to the processing from step S1 to step S11 described above, alignment (precise adjustment) between the photographing optical axis OA of the high-magnification microscope 23A and the rotation axis C is performed, and the correction position (precision correction position) of the rotation axis C is adjusted. decide.

[Effect of the first embodiment]
As described above, according to the dicing apparatus 10 of the first embodiment, by setting the photographing condition of the work holding surface 31a to the condition that the trajectory 82 is generated in the photographed image 80, the trajectory 82 in the photographed image 80 can be obtained. The position of the arc center can be determined as the position of the rotation axis C of the worktable 31 . This makes it possible to determine the position of the rotation axis C in the captured image 80 even if the position of the rotation axis C is the dark spot portion 84 (porous hole) shown in FIG. Further, the position of the rotation axis C can be determined without the operator memorizing the position of the rotation axis C or detecting the reference pattern itself on the workpiece holding surface 31a. As a result, the position of the rotation axis C can be determined with high accuracy, so that the alignment between the rotation axis C and the photographing optical axis OA can be performed with high accuracy.

[Dicing apparatus of the second embodiment]
FIG. 11 is a functional block diagram of the integrated control section 60 of the dicing apparatus 10 of the second embodiment. In the dicing machine 10 of the first embodiment, the position of the rotation axis C is determined within the auxiliary screen 68 (photographed image 80) by the operator's manual operation. position is determined automatically.

In the dicing apparatus 10 of the second embodiment, except that the integrated control section 60 functions as a light amount determination section 90, a position determination section 92, and a repeat control section 94 instead of the position determination section 76 of the first embodiment. , has basically the same configuration as the dicing apparatus 10 of the first embodiment. For this reason, the same reference numerals are given to the same functions or configurations as those of the first embodiment, and the description thereof will be omitted.

The image acquisition unit 74 of the second embodiment outputs the image data of the photographed image 80 acquired from the high-magnification microscope 23A during the alignment work to the light amount determination unit 90 in addition to the display control unit 75 .

During alignment work, the light intensity determination unit 90 analyzes the image data of the captured image 80 input from the image acquisition unit 74 and determines whether or not the amount of illumination light emitted from the light source used is excessive. do. For example, the light amount determination unit 90 calculates the average value of the luminance values of the pixels of the image data of the captured image 80, and determines whether or not the average value is greater than a predetermined upper limit value. Determine whether or not it is excessive. Note that this determination method is not limited to the method described above, and any method may be used. Then, the light intensity determination unit 90 outputs the image data of the captured image 80 input from the image acquisition unit 74 to the position determination unit 92 when determining that the light intensity of the illumination light is not excessive, that is, is appropriate.

On the other hand, when the light quantity determination unit 90 determines that the light quantity of the illumination light is excessive, there is a possibility that overexposure or the like may occur in the photographed image 80. A re-shooting command is issued to the shooting control unit 71 . Accordingly, the illumination control unit 72 receives the light amount adjustment command and reduces the light amount of the illumination light emitted from the light source used by a predetermined ratio. Further, the imaging control unit 71 receives a re-imaging command and causes the high-magnification microscope 23A to perform re-imaging of the workpiece holding surface 31a. As a result, the image data of the new captured image 80 is input to the light intensity determination section 90 via the image acquisition section 74 .

The light amount adjustment of the light source used by the illumination control section 72 and re-imaging by the high-magnification microscope 23A are repeatedly executed until the light amount determination section 90 determines that the light amount of the illumination light is appropriate.

The position determination unit 92 performs image analysis on the image data of the captured image 80 input from the image acquisition unit 74 via the light amount determination unit 90 to determine the position of the arc center of the trajectory 82 in the captured image 80, that is, the rotation axis. Determine the position of C automatically. The position determination section 92 has a trajectory detection section 92A and a position calculation section 92B.

FIG. 12 is an explanatory diagram for explaining detection processing of the trajectory 82 by the trajectory detection section 92A. As shown in FIG. 12, the trajectory detection section 92A performs image analysis on the image data of the captured image 80 input from the light amount determination section 90, and detects a trajectory 82 in the captured image 80. FIG. For example, the trajectory detection unit 92A detects a point group 96 corresponding to each trajectory 82 from the captured image 80 by performing known edge extraction processing on the image data of the captured image 80 . Note that the method for detecting the trajectory 82 is not limited to the edge extraction method, and a known feature detection method (feature extraction method) such as a pattern detection method can be used.

Each point group 96 is an aggregation of a plurality of detection points 96a. In addition, in FIG. 12, the point group 96 is simplified and illustrated in order to prevent the drawing from becoming complicated. Then, the trajectory detection unit 92A calculates the position coordinates of each detection point 96a in the point group 96 (hereinafter simply referred to as the point group position coordinates) for each point group 96 as the detection result of the trajectory 82 in the captured image 80. Output to section 92B.

Returning to FIG. 11, the position calculation unit 92B calculates the position of the arc center in the captured image 80, That is, the position of the rotation axis C is calculated.

FIG. 13 is an explanatory diagram for explaining the first method of calculating the position of the rotation axis C by the position calculating section 92B. As indicated by symbol XIIIA in FIG. 13, the position calculation unit 92B uses, for example, the least squares method based on the detection result of the point group position coordinates by the trajectory detection unit 92A to pass through the point group 96 for each point group 96. A circumference CR, that is, an equation (approximate expression) of the circumference CR including the trajectory 82 as a part is calculated. This equation is expressed by the center position coordinates of the circumference CR and the radius. Thereby, the center position 97 is calculated for each circumference CR. Note that the center position 97 of the circumference CR corresponds to the position of the arc center of the trajectory 82 including the circumference CR.

Next, as indicated by symbol XIIIB in FIG. 13, the position calculator 92B compares the position coordinates of the center position 97 for each circumference CR, and finds an outlier 97E (outlier or abnormal value) in each center position 97. ) is included. For example, the position calculation unit 92B determines a center position 97 that is separated from the average value of the position coordinates of each center position 97 by a standard deviation α (α is an arbitrary natural number) times or more as an outlier 97E. Note that the method of determining the outlier 97E is not limited to the method described above, and various known methods can be employed.

Then, the position calculation unit 92B calculates the average value of the position coordinates of each center position 97 (within the dotted line frame in the figure) excluding the outlier CE, and calculates the average value of the position coordinates as indicated by symbol XIIIC in FIG. The average value is determined as the position of the axis of rotation C.

FIG. 14 is an explanatory diagram for explaining the second calculation method of the position of the rotation axis C by the position calculator 92B. As indicated by symbol XIVA in FIG. 14, the position calculation unit 92B calculates any two detection points 96a in the point group 96 for each point group 96 based on the detection result of the point cloud position coordinates by the trajectory detection unit 92A. A perpendicular bisector LD (a normal to the midpoint of the straight line) of the straight line connecting is calculated.

Then, the position calculator 92B calculates the position coordinates of the intersection 98 of each perpendicular bisector LD. For example, when the number of perpendicular bisectors LD is m, the number of intersections 98 is _m C ₂ =[m(m−1)]/2. In the drawing, since the two perpendicular bisectors LD are substantially parallel, one of the intersections 98 is located outside the captured image 80. FIG.

Next, as indicated by symbol XIVB in FIG. 14, the position calculation unit 92B compares the position coordinates of each intersection point 98 and determines whether each intersection point 98 includes an outlier 98E. determine whether or not there is Then, the position calculation unit 92B calculates the average value of the position coordinates of each intersection point 98 (within the dotted line frame in the figure) excluding the outlier 98E, and calculates the average value of the position coordinates as indicated by symbol XIVC in FIG. A value is determined as the position of the axis of rotation C.

FIG. 15 is an explanatory diagram for explaining the third calculation method of the position of the rotation axis C by the position calculator 92B. In the first calculation method and the second calculation method, the position of the rotation axis C is calculated based on the detection result of the point group position coordinates for each of the plurality of point groups 96 (locus 82). The position of the rotation axis C is calculated based on the detection result of the point group position coordinates of the two point groups 96 (trajectory 82).

As shown in FIG. 15, the position calculator 92B divides one point group 96 (trajectory 82) into two groups based on the detection result of the point group position coordinates. Next, for each group, the position calculator 92B calculates a vertical bisector LD of a straight line connecting any two detection points 96a in the group. Then, the position calculator 92B determines the position coordinates of the intersection of the two perpendicular bisectors LD as the position of the rotation axis C. FIG.

FIG. 16 is an explanatory diagram for explaining a fourth method of calculating the position of the rotation axis C by the position calculator 92B. In this fourth calculation method, the position of the rotation axis C is calculated based on the detection result of the point group position coordinates of the locus 82 with a large diameter. Therefore, when using the fourth calculation method, the trajectory detection unit 92A selectively detects the point group position coordinates of the large-diameter trajectory 82 by, for example, the edge extraction method.

As indicated by symbol XVIA in FIG. 16, the position calculation unit 92B calculates the outer circumference of the locus 82 using the least squares method or the like based on the detection result of the point group position coordinates of the point group 96 corresponding to the locus 82 with a large diameter. A plurality of arcs 99 having different radii r from the center of the arc, such as the inner circumference, are calculated. Although two types of arcs 99 are calculated in the drawing, three or more types of arcs 99 may be calculated.

Then, the position calculator 92B calculates the center position 97 for each arc 99 using the above-described first calculation method (other calculation methods are also possible). Next, as indicated by XVIB in FIG. 16, the average value of the position coordinates of each center position 97 (excluding the position coordinates of the outlier 97E) is calculated, and the average value of the position coordinates is determined as the position of the rotation axis C. do.

The first to fourth calculation methods described above may be used individually, or may be used in combination as appropriate.

FIG. 17 is an explanatory diagram for explaining the effect of calculating the position of the rotation axis C by the first to fourth calculation methods. Note that FIG. 17 illustrates the third calculation method as an example, but the same applies to other calculation methods. As shown in FIG. 17, in any of the first to fourth calculation methods, the position coordinates of the rotation axis C can be calculated based on the detection result of the trajectory 82 by the trajectory detector 92A. As a result, unlike the first embodiment, even if the rotation axis C does not exist in the captured image 80, the position of the rotation axis C can be automatically determined.

Returning to FIG. 11, the position calculation unit 92B outputs rotation axis position information indicating the position (position coordinates) of the rotation axis C to the corrected position calculation unit 77 based on the determination result of the position of the rotation axis C. FIG. Accordingly, the corrected position calculator 77 calculates the corrected position of the rotation axis C in the same manner as in the first embodiment, and outputs the calculated results to the movement controller 69 and the repetition controller 94, respectively.

The movement control section 69 drives the X drive section 35 and the Y drive section 46 based on the corrected position of the rotation axis C input from the position calculation section 92B, and moves the high-magnification microscope 23A and the work table 31 in the X-axis direction. And by relatively moving in the Y-axis direction, alignment between the photographing optical axis OA and the rotation axis C is performed. In this case, the X drive section 35 and Y drive section 46 function as the relative movement section of the present invention.

The repetition control unit 94 determines whether or not the amount of relative movement between the high-power microscope 23A and the work table 31 is greater than a predetermined threshold based on the correction value input from the correction position calculation unit 77 . Then, when the relative movement amount is larger than the threshold, the repetition control unit 94 controls the rotation control unit 70, the shooting control unit 71, the illumination control unit 72, the image acquisition unit 74, the light amount determination unit 90, the position determination unit 92, the correction The position calculation unit 77, the movement control unit 69, etc. are repeatedly operated. As a result, each process such as rotation of the work table 31, illumination and photographing of the work holding surface 31a, determination of the amount of light, image analysis of the photographed image 80 (determination of the position of the rotation axis C), and calculation of the correction position is repeatedly executed. . Hereinafter, repetition of each process is referred to as "repeated process".

Then, the repetition control unit 94 repeats the above operations until the amount of relative movement between the high-magnification microscope 23A and the work table 31 is within a predetermined threshold value and the relative movement between the high-magnification microscope 23A and the work table 31 is substantially eliminated. Continue the iteration. As a result, alignment between the photographing optical axis OA and the rotation axis C is completed.

Note that, when the repetition processing by the repetition control unit 94 is completed, the overall control unit 60 stores the position coordinates (x, y) of the photographing optical axis OA and the rotation axis C in the storage unit 64 .

[Action of the dicing machine of the second embodiment]
FIG. 18 is a flow chart showing the flow of alignment work between the imaging optical axis OA of the high-magnification microscope 23A and the rotation axis C of the work table 31 in the dicing apparatus 10 of the second embodiment. Note that the processing up to step S4 is the same as that of the first embodiment shown in FIG. 10, and therefore detailed description will be omitted.

The image data of the photographed image 80 of the workpiece holding surface 31a photographed by the high-magnification microscope 23A in step S4 is output from the high-magnification microscope 23A to the light intensity determination section 90 via the image acquisition section 74. FIG. Upon receiving the image data of the captured image 80, the light amount determination unit 90 analyzes the image data and determines whether or not the amount of illumination light emitted from the light source used is excessive (step S20).

When the light amount determination unit 90 determines that the light amount of the illumination light is not excessive, that is, is appropriate, the light amount determination unit 90 outputs the image data of the photographed image 80 to the position determination unit 92 (NO in step S21).

On the other hand, when the light amount determination unit 90 determines that the light amount of the illumination light is excessive, it issues a light amount adjustment command to the illumination control unit 72 and issues a re-shooting command to the shooting control unit 71 (step S21). YES). As a result, the illumination control unit 72 adjusts the amount of illumination light emitted from the light source used to reduce the amount of illumination light, and the imaging control unit 71 causes the high-magnification microscope 23A to re-image the workpiece holding surface 31a. As a result, the image data of the new captured image 80 is input to the light intensity determination section 90 via the image acquisition section 74 . Thereafter, the processes of steps S22, S4, and S20 are repeatedly executed until the light amount determination unit 90 determines that the light amount of the illumination light is appropriate.

The trajectory detection unit 92A of the position determination unit 92 performs edge extraction processing and the like on the image data of the captured image 80 input from the light amount determination unit 90, thereby obtaining the captured image 80 as shown in FIG. A point group 96 corresponding to each trajectory 82 is detected from within (step S23). Then, the trajectory detection section 92A outputs the detection result of the point group position coordinates for each point group 96 to the position calculation section 92B.

Next, based on the detection result of the trajectory detection unit 92A, the position calculation unit 92B performs calculation processing for calculating the center position 97 using, for example, the first calculation method shown in FIG. 13 (step S24). . At this time, if an outlier 97E exists in each of the calculated center positions 97 (YES in step S25), the position calculator 92B removes the outlier 97E (step S26).

The position calculator 92B calculates the average value of the position coordinates of each center position 97, and determines this average value as the position of the rotation axis C (step S27, corresponding to the position determination step of the present invention). In addition, instead of using the first calculation method, the position calculation unit 92B uses any one of the second to fourth calculation methods shown in FIGS. The position of the rotation axis C may be obtained by appropriately combining the fourth calculation methods.

Then, the position calculation section 92B outputs rotation axis position information indicating the position of the rotation axis C to the corrected position calculation section 77 . As a result, the calculation of the correction position by the correction position calculation unit 77 (step S28) and the relative movement of the high-magnification microscope 23A and the work table 31 by the movement control unit 69, that is, the alignment of the imaging optical axis OA and the rotation axis C ( Step S29) and are executed.

In addition, based on the correction value input from the correction position calculation unit 77, the repeat control unit 94 determines that the total control unit 60 to execute the above-described repetitive processing (YES in step S30). Thereby, the alignment between the photographing optical axis OA and the rotation axis C can be performed with high accuracy.

[Effect of Second Embodiment]
As described above, according to the dicing apparatus 10 of the second embodiment, the position of the rotation axis C can be automatically and accurately determined by image analysis of the image data of the photographed image 80 photographed under the condition that the locus 82 is generated. can be determined to As a result, the alignment between the rotation axis C and the photographing optical axis OA can be performed automatically and with high precision.

[Dicing apparatus of the third embodiment]
In the second embodiment, the arc-shaped locus 82 in the captured image 80 is detected by the locus detection unit 92A. becomes approximately linear. In this case, the position calculator 92B cannot determine the position of the rotation axis C using any of the above-described first to fourth calculation methods.

Therefore, in the dicing apparatus 10 of the third embodiment, when the distance between the rotation axis C and the imaging optical axis OA is long, the alignment (rough adjustment) between the imaging optical axis OB of the low-magnification microscope 23B and the rotation axis C is performed. ), alignment (precise adjustment) between the photographing optical axis OA of the high-magnification microscope 23A and the rotation axis C is performed. The dicing machine 10 of the third embodiment has basically the same configuration as that of the dicing machine 10 of the second embodiment. and the description thereof is omitted.

FIG. 19 is a flow chart showing the flow of alignment work between the imaging optical axis OA of the high-magnification microscope 23A and the rotation axis C of the work table 31 in the dicing apparatus 10 of the third embodiment. Note that the processing up to step S23 is the same as that of the second embodiment shown in FIG. 18, so detailed description thereof will be omitted.

Based on the detection result of the locus detection unit 92A, the position calculation unit 92B of the third embodiment first uses, for example, the least squares method to determine whether or not the lines passing through each point group 96 are straight lines. (Step S23A). When a line passing through any one of the point groups 96 is straight, the position calculation unit 92B issues a microscope switching command to the movement control unit 69 and a re-capture command to the imaging control unit 71. Yes (YES in step S23A).

Upon receiving the microscope switching command, the movement control unit 69 drives the X drive unit 35 and the Y drive unit 46 based on the above-described relative position information (not shown), thereby photographing the high-power microscope 23A on the work table 31. The position of the optical axis OA and the position of the imaging optical axis OB of the low-magnification microscope 23B are exchanged (step S23B). As a result, the workpiece holding surface 31a (rotating axis C) is set within the field of view of the low-magnification microscope 23B.

Next, the imaging control unit 71 receives a re-imaging command, and causes the low-magnification microscope 23B to re-image the workpiece holding surface 31a after the above-described microscope switching. As a result, the image data of the new captured image 80 is input to the light quantity determination section 90 via the image acquisition section 74 . Then, steps S20 and S21 (light amount determination) and steps S23 and S23A (trajectory detection) described above are executed. At this time, since the low-magnification microscope 23B has a wider field of view than the high-magnification microscope 23A, the apparent distance between the rotation axis C and the photographing optical axis OB is the distance between the rotation axis C and the photographing optical axis OA. shorter than the apparent distance between As a result, an arc-shaped trajectory 82 is generated in the captured image 80 captured by the low-magnification microscope 23B (NO in step S23A). Thereafter, by performing the processes from step S24 to step S29 described above, the imaging optical axis OB and the rotation axis C of the low-magnification microscope 23B are aligned.

After completing alignment between the imaging optical axis OB and the rotation axis C, the repetition control unit 94 of the third embodiment issues a microscope switching command to the movement control unit 69 in order to switch to imaging with the high-magnification microscope 23A ( NO in step S30, YES in step S31). Receiving this command, the movement control section 69 drives the X drive section 35 and the Y drive section 46 based on the above-mentioned relative position information (not shown) to move the imaging optical axis of the high-magnification microscope 23A on the rotation axis C. The position of the OA and the position of the imaging optical axis OB of the low-magnification microscope 23B are exchanged again (step S32).

When the switching from the low-magnification microscope 23B to the high-magnification microscope 23A is completed, the photographing optical axis OA of the high-magnification microscope 23A is roughly aligned with the rotation axis C. As a result, the arc-shaped trajectory 82 is reliably generated in the photographed image 80 photographed by the high-magnification microscope 23A, so the position of the rotation axis C can be determined from the photographed image 80. FIG.

Next, the repetition control section 94 of the third embodiment controls each section of the integrated control section 60 to execute the above-described repetition processing (steps S4 to S29). Accordingly, as in the second embodiment, alignment between the photographing optical axis OA and the rotation axis C can be performed automatically and with high accuracy.

[others]
In each of the above embodiments, the condition setting unit 73 sets the exposure time for photographing with the high-magnification microscope 23A longer than the normal exposure time described above. The angular velocity (rotational velocity) of the table 31 may be set higher than the normal angular velocity for dicing the workpiece W. As a result, the same effect as when the exposure time is lengthened can be obtained, and the trajectory 82 can be generated in the captured image 80 . Also, the setting of the exposure time and the setting of the angular velocity may be combined.

The correction position calculation unit 77 in each of the above embodiments calculates the correction position of the rotation axis C, but instead of calculating the correction position of the rotation axis C, the photographing optical axis OA for matching with the rotation axis C is calculated. A correction position may be calculated. In this case, by correcting the position of the photographing optical axis OA (high-magnification microscope 23A) based on this corrected position, the rotational axis C and the photographing optical axis OA can be aligned. Further, the correction position calculation section 77 may calculate correction positions of both the rotation axis C and the imaging optical axis OA so as to match the rotation axis C and the imaging optical axis OA.

In each of the embodiments described above, the integrated control unit 60 is provided in the dicing apparatus 10 , but an arithmetic device such as a personal computer provided separately from the dicing apparatus 10 may be used as the integrated control unit 60 .

In each of the above-described embodiments, the workpiece holding surface 31a is formed in a porous shape, and a reference pattern (not shown) of an arbitrary shape or a similar pattern (marks, patterns, members, etc.) is formed on the workpiece holding surface 31a. In this case, the workpiece holding surface 31a may be mirror-finished. In this case as well, the center of the arc of the trajectory 82 drawn by the reference pattern or the like is determined as the position of the rotation axis C instead of directly detecting the reference pattern or the like.

In the above embodiment, the imaging unit 23 has the high-magnification microscope 23A and the low-magnification microscope 23B. The present invention can also be applied to For example, when using three types of microscopes with "low", "medium", and "high" imaging magnifications, the above-described alignment may be performed in the order of "low", "medium", and "high". Also, if you take a picture with a microscope with a "high" magnification and fail to align the image, take a picture with a microscope with a "medium" magnification, and then align the image with a microscope with a "medium" magnification. In case of failure, photographing is performed using a microscope with a "low" photographing magnification. Conversely, if alignment is successful even with a microscope with a "medium" imaging magnification, imaging is performed again with a microscope with a "high" imaging magnification.

In the above-described embodiment, the assisting of alignment between the imaging optical axis OA of the imaging unit 23 in the dicing apparatus 10 and the rotation axis C of the work table 31 has been described as an example. The present invention can also be applied when aligning the photographing optical axis of the photographing unit with the rotation axis C of various tables.

10... dicing device,
23A...High magnification microscope,
23B ... low magnification microscope,
23... Imaging unit,
31 work table,
31a work holding surface,
52... ring illumination light source,
60 ... integrated control unit,
62 operation unit,
68 Auxiliary screen,
69 ... movement control unit,
70 ... Rotation control unit,
71 photographing control unit,
72 ... lighting control unit,
73 condition setting unit,
75 ... display control unit,
76 ... positioning unit,
77 ... correction position calculation unit,
80... photographed image,
82 trajectory,
86 ... optical axis index,
88 ... movement index,
90... Light amount determination unit,
92 ... positioning unit,
92A... trajectory detection unit,
92B ... position calculation unit,
94... Repetition control unit

Claims (11)

A photographing unit having a rotating shaft of a table that has a work holding surface for holding a work and rotates about the rotating shaft, and a photographing optical axis arranged at a position facing the work holding surface and parallel to the rotating shaft. In the auxiliary device that assists the alignment of the imaging optical axis of
a rotation control unit that drives a rotation drive unit of the table to rotate the table;
a photographing control unit that causes the photographing unit to photograph the work holding surface while the table is being rotated by the rotation driving unit, and that causes the photographing unit to output a photographed image of the work holding surface;
a condition setting unit that sets, as a photographing condition of the photographed image, a condition in which an arc-shaped trajectory drawn by a bright spot portion in the photographed image that rotates around the rotation axis can be photographed;
a position determination unit that determines the arc center of the trajectory in the captured image output from the imaging unit as the position of the rotation axis;
Auxiliary equipment with The imaging condition is the exposure time of the imaging unit,
2. The auxiliary device according to claim 1, wherein the condition setting unit sets the exposure time longer than the normal exposure time when the photographing unit photographs the workpiece held on the workpiece holding surface. an illumination control unit configured to control the illuminance of illumination light applied to the workpiece holding surface or the workpiece from an illumination light source provided in the photographing unit;
The imaging conditions include the exposure time and the illuminance,
3. The auxiliary device according to claim 2, wherein the condition setting unit sets the illuminance to be lower than the normal illuminance of the illumination light applied to the workpiece. the rotation control unit maintains the angular velocity of the table at a constant speed within a predetermined period when the table is rotated by the rotation drive unit;
4. The auxiliary device according to claim 2, wherein the condition setting unit sets the start timing and the end timing of the exposure time within the period. A ring illumination light source having a plurality of light sources arranged at equal angular pitches along a circumference direction centered on the photographing optical axis is provided in the photographing unit, and the equal angular pitch is θp 5. The auxiliary device according to claim 1, wherein θc≧θp or θc=n×θp, where θc is the rotation angle of the table and n is an arbitrary natural number. a display control unit for displaying the photographed image output from the photographing unit on a display unit;
an operation unit that receives input of a designation operation for designating a position of the arc center of the trajectory in the captured image displayed on the display unit;
with
6. The auxiliary device according to any one of claims 1 to 5, wherein the position determination unit determines the position of the rotation shaft based on the specified operation input to the operation unit. Correction position calculation for calculating a correction position of the rotation axis coinciding with the photographing optical axis based on the known position of the photographing optical axis in the photographed image and the position of the rotation axis determined by the position determination unit 7. The auxiliary device of claim 6, comprising a section. The position determination unit
a trajectory detection unit that analyzes the captured image output from the imaging unit and detects the trajectory in the captured image;
a position calculation unit that calculates the position of the rotation axis based on the detection result of the trajectory by the trajectory detection unit;
6. An auxiliary device according to any one of claims 1 to 5, comprising: calculating a correction position for matching the photographic optical axis and the rotational axis based on the known position of the photographic optical axis in the photographic image and the position of the rotational axis determined by the position determining unit; a correction position calculator;
driving a relative movement unit that relatively moves the photographing unit and the table in a direction perpendicular to the rotation shaft based on the calculation result of the correction position by the correction position calculation unit; a movement control unit that aligns with the axis;
The rotation control unit, the photography control unit, the position determination unit, and the movement control until the amount of relative movement by which the imaging unit and the table are relatively moved by the relative movement unit is within a range of a predetermined threshold value. a repeat control unit that repeatedly operates the unit;
9. The auxiliary device of claim 8, comprising: 10. The assistant according to any one of claims 1 to 9, wherein the photographing control unit causes the photographing unit to photograph the porous workpiece holding surface rotated about the rotation axis by the rotation driving unit. Device. A photographing unit having a rotating shaft of a table that has a work holding surface for holding a work and rotates about the rotating shaft, and a photographing optical axis arranged at a position facing the work holding surface and parallel to the rotating shaft. In the auxiliary method for assisting the alignment of the imaging optical axis of
a rotation control step of rotating the table;
a photographing control step of causing the photographing unit to photograph the work holding surface while the table is being rotated in the rotation control step, and outputting a photographed image of the work holding surface from the photographing unit;
a condition setting step of setting the photographing condition of the photographed image to a condition in which an arc-shaped trajectory drawn by a bright spot portion in the photographed image rotating about the rotation axis can be photographed;
a position determination step of determining the arc center of the trajectory in the captured image output from the imaging unit as the position of the rotation axis;
Auxiliary method with

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