JP4872186B2 - Alignment method and alignment program in laser processing apparatus - Google Patents

Description

  The present invention relates to an alignment method in a processing apparatus that performs fine processing using laser light.

  In the formation of devices using silicon or the like as a base substrate, a number of devices having the same shape and structure are integrally formed by using fine processing technology such as thin film formation technology and photolithography technology, and then predetermined cutting is performed. Generally, it is performed through a process of cutting into individual devices by means. In this case, in the final cutting step, precise positioning and alignment of the cut portion, so-called alignment is required. For such alignment, a method in which a predetermined marker is formed on a substrate in advance, or a part to be handled as a marker from a predetermined pattern shape is determined in advance, and this is performed based on the arrangement position or the like is simple and versatile. It is widely known. Also, there are known techniques that do not use such markers (see, for example, Patent Document 1). Patent Document 1 discloses a system that performs alignment by performing pattern matching at a certain position and a position rotated by 90 ° from the position.

  Further, as a means for cutting or cutting as described above, a technique using a laser beam has been widely used. In recent years, substrates such as sapphire, which have high hardness and brittleness, and short-wavelength LDs (laser diodes), LEDs (light-emitting diodes) using wide band gap compound semiconductor thin films such as GaN on the substrate materials have been developed. Laser light is also used for cutting and processing the formed one (for example, see Patent Document 2). Patent Document 2 discloses a laser processing apparatus that uses laser light as cutting means (cutting means).

JP 61-143820 A JP 2004-1114075 A

  When a laser processing apparatus as disclosed in Patent Document 2 is used, the cut line is made narrower than a mechanical cutting apparatus using a diamond blade or the like by setting the beam diameter of the laser beam to an appropriate value. As a result, the so-called street portion through which the cut line passes can be made thinner, so that the number of devices can be improved. This is particularly effective in the case of a micro-sized device that is much smaller than 1 mm.

  However, on the other hand, the smaller the device size, the higher the accuracy required for the cutting position. That is, it is necessary to have an alignment technique that accurately grasps the position and orientation (angle) of the substrate and corrects it accurately if necessary.

  In the case of using the angle correction method using the marker as described above, it is generally preferable from the point of position accuracy that the marker is formed minutely as the device becomes minute, but the marker becomes smaller as the device becomes minuter. There is a problem that it is difficult to detect.

  On the other hand, the method disclosed in Patent Document 1 is complicated because the 90 ° rotation operation is essential in the middle, and acquisition of a high-magnification image and setting of an initial position using an orientation flat are necessary. It is considered that the smaller the target device is, the more difficult it is to secure its accuracy.

  The present invention has been made in view of the above problems, and in a laser processing apparatus, when a workpiece formed by integrally forming a number of micro devices having the same shape and structure is cut and processed, it is used for alignment. It is an object of the present invention to provide a method that allows easy and accurate alignment without setting marker points.

In order to solve the above-mentioned problems, the invention of claim 1 is a processing apparatus that performs processing using a light beam emitted from a predetermined light source as a processing means, in which a large number of devices having the same shape and structure are integrally formed. This is a method of aligning the workpiece when performing a process of cutting a workpiece in which a repetitive pattern of a plurality of unit elements having the same shape on the surface is two-dimensionally cut for each unit element. A) a workpiece holding step of holding the workpiece by a predetermined holding means so as to be able to rotate in-plane with respect to a predetermined reference coordinate plane; and b) of the repetitive pattern in the reference coordinate plane. A rough angle correction step for coarsely correcting the inclination; and c) a fine angle correction step for precisely correcting the inclination of the repetitive pattern in the reference coordinate plane that has undergone the rough angle correction step, and the rough angle The normal step is b-1) predetermined orthogonal coordinates in which arrangement positions of a plurality of partial unit elements included in a predetermined range among the unit elements forming the repetitive pattern are fixed relative to the reference coordinate plane A partial unit element position detecting step for detecting the coordinate value in the system; and b-2) a first straight line representing the arrangement direction of the plurality of partial unit elements is a first coordinate axis of the predetermined orthogonal coordinate system. A first angle calculating step of calculating a first angle based on the coordinate value; and b-3) the inclination of the repetitive pattern with respect to the first coordinate axis is eliminated using the first angle as a rotation angle. A first rotation step of rotating the workpiece in a direction, and the precision angle correction step is c-1) an integral multiple of the unit element in the first coordinate axis direction from the rotation center position in the rotation step. Exists at the end position separated by An end position specifying step for specifying the arrangement position of the unit elements; c-2) a second position connecting the rotation center position and the arrangement position of the one unit element obtained by the end position specifying step; A second angle calculating step of calculating a second angle formed by a straight line and the first coordinate axis; c-3) using the second angle as a rotation angle, an inclination of the repetitive pattern with respect to the first coordinate axis is A second rotation step of rotating the workpiece in a direction to be erased.

According to a second aspect of the present invention, in a processing apparatus that performs processing using a light beam emitted from a predetermined light source as a processing means , a plurality of devices having the same shape and structure are integrally formed to be the same on the surface. when performing machining repeating pattern of a plurality of unit elements having the shape to cut the two-dimensionally formed comprising workpiece for each unit element, said a method of aligning a workpiece, a) predetermined A workpiece holding step for holding the workpiece by a predetermined holding means so that the workpiece can be rotated in-plane with respect to the reference coordinate plane; and b) coarsely correcting the inclination of the repetitive pattern in the reference coordinate plane. A rough angle correction step, and c) a fine angle correction step for precisely correcting the inclination of the repetitive pattern in the reference coordinate plane that has undergone the rough angle correction step, and the rough angle correction step includes b-1 ) A portion for detecting the arrangement position of a plurality of partial unit elements included in a predetermined range among unit elements forming a repetitive pattern as coordinate values in a predetermined orthogonal coordinate system fixed relative to the reference coordinate plane A unit element position detecting step; and b-2) a first angle formed by a first straight line representing the arrangement direction of the plurality of partial unit elements with a first coordinate axis of the predetermined orthogonal coordinate system, the coordinate value B-3) rotating the workpiece in a direction in which the inclination of the repetitive pattern with respect to the first coordinate axis is eliminated, using the first angle as a rotation angle. And c-1) across the rotation center position in the rotation process, each of the first coordinate axis directions from the rotation center position to the unit element. An integer multiple of distance An end position specifying step for specifying an arrangement position of one unit element existing at the first and second end positions apart from each other; c-2) the one unit at the first and second end positions; A second angle calculating step of calculating a second angle formed by a second straight line connecting the arrangement positions of the elements and the first coordinate axis; and c-3) using the second angle as a rotation angle, the first angle And a second rotation step of rotating the workpiece in a direction in which the inclination of the repetitive pattern with respect to the coordinate axis is erased.

  The invention according to claim 3 is the alignment method according to claim 1 or 2, further comprising: d) a temporary center setting step for determining a temporary center of the repetitive pattern, wherein the temporary center setting step includes: A step performed prior to the rough angle correction step, d-1) a temporary center specifying step of specifying the temporary center based on geometric features of the workpiece; and d-2) the temporary A first translation step of making the center coincide with the rotation center, and in the partial unit element position detection step, the predetermined range is determined with the temporary center as the center, and the first and second rotation steps In each case, the temporary center is used as a rotation center.

  Further, the invention of claim 4 is the alignment method according to claim 3, wherein the workpiece has a disk shape, and in the temporary center specifying step, the outer circumference of the workpiece is An intersection point of two perpendicular bisectors of two strings is defined as the temporary center.

  The invention according to claim 5 is the alignment method according to claim 3 or 4, further comprising: e) a true center detecting step of detecting a true center of the repetitive pattern, wherein the true center detecting step E-1) a relative positional relationship specifying step of specifying a relative positional relationship between a street intersection that can be the true center in the repetitive pattern and a unit element near the intersection; and e-2) a unit element near the intersection A true center setting step for determining the true center based on the position of the position, the position of the temporary center, and the relative positional relationship; and e-3) setting the true center determined in the true center setting step as the temporary center. A second translational movement step of translating the workpiece so as to coincide with the second translational movement step.

In the invention of claim 6, a plurality of devices having the same shape and structure are integrally formed so that a repeated pattern of a plurality of unit elements having the same shape is formed two-dimensionally on the surface. With respect to the work piece, the work piece is held by a predetermined holding means so as to be rotatable in a plane within a predetermined reference coordinate plane, and the work piece is set for each unit element using a light beam emitted from a predetermined light source as the processing means. A program that realizes alignment of the workpiece in the processing apparatus by being executed in a computer of a control means that controls a processing apparatus that performs processing that cuts into a, and a) a temporary center of the repetitive pattern A provisional center setting step to be determined; b) a rough angle correction step for roughly correcting the inclination of the repetitive pattern in the reference coordinate plane; and c) the rough angle correction step. A precision angle correction step for precisely correcting the inclination of the repetitive pattern in the reference coordinate plane, and d) a true center detection step for detecting a true center of the repetitive pattern, and a program for causing the computer to execute the step. The temporary center setting step includes: a-1) a temporary center specifying step of specifying the temporary center according to geometric characteristics of the workpiece; and a-2) moving the holding means by a predetermined horizontal driving means. A first translational movement step for causing the temporary center to coincide with the rotational center, and the rough angle correcting step is b-1) centering on the temporary center among the unit elements forming the repetitive pattern. A partial unit element position detecting step for detecting the arrangement positions of a plurality of partial unit elements included in a predetermined range as coordinate values in a predetermined orthogonal coordinate system fixed relative to the reference coordinate plane; b- 2) A first angle calculating step of calculating, based on the coordinate values, a first angle formed by a first straight line representing the arrangement direction of the plurality of partial unit elements with a first coordinate axis of the predetermined orthogonal coordinate system; B-3) a first rotation step of rotating the repetitive pattern around the temporary center in a direction in which the inclination is eliminated by using the first rotation angle as a rotation angle by a predetermined rotation driving means; The precise angle correction step c-1) specifies an arrangement position of one unit element existing at an end position that is separated from the temporary center in the first coordinate axis direction by an integral multiple of the unit element. An end position specifying step; and c-2) a second straight line connecting the temporary center and the opposing position of the one unit element obtained by the end position specifying step is the first coordinate axis. A second angle calculating step of calculating an angle of 2, and c-3) the rotation A second rotation step of rotating the repetitive pattern around the temporary center in a direction in which the inclination is eliminated by moving means with the second angle as a rotation angle, and the true center detection step comprises: d-1) a relative positional relationship specifying step for specifying a relative positional relationship between an intersection of a street that can be the true center in the repetitive pattern and a unit element near the intersection; and d-2) a position of the unit element near the intersection A true center setting step for determining the true center based on the position of the temporary center and the relative positional relationship; and d-3) the true center determined in the true center setting step by the horizontal driving means. A second translational movement step of translating the workpiece so that the temporary center is located at a certain position.

In the invention of claim 7, a plurality of devices having the same shape and structure are integrally formed so that a repeating pattern of a plurality of unit elements having the same shape is formed two-dimensionally on the surface. With respect to the workpiece, the workpiece is held by a predetermined holding means so as to be rotatable in a plane within a predetermined reference coordinate plane, and the workpiece is unit-unit- elemented using a light beam emitted from a predetermined light source as the processing means A program that realizes alignment of the workpiece in the processing apparatus by being executed in a computer of a control means that controls a processing apparatus that performs processing that cuts into a, and a) a temporary center of the repetitive pattern A provisional center setting step to be determined; b) a rough angle correction step for roughly correcting the inclination of the repetitive pattern in the reference coordinate plane; and c) the rough angle correction step. A precision angle correction step for precisely correcting the inclination of the repetitive pattern in the reference coordinate plane, and d) a true center detection step for detecting a true center of the repetitive pattern, and a program for causing the computer to execute the step. The temporary center setting step includes: a-1) a temporary center specifying step of specifying the temporary center according to geometric characteristics of the workpiece; and a-2) moving the holding means by a predetermined horizontal driving means. A first translational movement step for causing the temporary center to coincide with the rotational center, and the rough angle correcting step is b-1) centering on the temporary center among the unit elements forming the repetitive pattern. A partial unit element position detecting step for detecting the arrangement positions of a plurality of partial unit elements included in a predetermined range as coordinate values in a predetermined orthogonal coordinate system fixed relative to the reference coordinate plane; b- 2) A first angle calculating step of calculating, based on the coordinate values, a first angle formed by a first straight line representing the arrangement direction of the plurality of partial unit elements with a first coordinate axis of the predetermined orthogonal coordinate system; B-3) a first rotation step of rotating the repetitive pattern around the temporary center in a direction in which the inclination is eliminated by using the first rotation angle as a rotation angle by a predetermined rotation driving means; The precise angle correction step is c-1) with the rotation center position in the rotation step and the first coordinate axis direction being separated from the rotation center position by an integral multiple of the unit element, respectively. An end position specifying step for specifying an arrangement position of one unit element existing at the first and second end positions; c-2) an arrangement of the one unit element at the first and second end positions; The second straight line connecting the positions is A second angle calculating step of calculating a second angle with respect to the first coordinate axis, and c-3) a direction in which the inclination of the repetitive pattern is eliminated by setting the second angle as a rotation angle by the rotation driving means. A second rotation step of rotating the temporary center as a rotation center, wherein the true center detection step includes: d-1) a street intersection that can be the true center in the repetitive pattern, and unit elements in the vicinity of the intersection D-2) a true center that determines the true center based on the position of the unit element near the intersection, the position of the temporary center, and the relative position relationship. A setting step; d-3) a second translational movement step of translating the workpiece so that the true center determined in the true center setting step is located at a position where the temporary center is located by the horizontal driving means; And It is characterized by providing.
The invention according to claim 8 is the alignment method according to any one of claims 1 to 5, wherein the first angle calculation step includes the plurality of the plurality of pieces detected in the partial unit element position detection step. Of the coordinate values in the orthogonal coordinate system for the partial unit elements, the portions belonging to the same column in the repetitive pattern based on the values for the second coordinate axis orthogonal to the first coordinate axis The step of classifying each unit element, and using the coordinate values of at least two partial unit elements classified as belonging to the same column, obtaining the inclination angle of the column with respect to the first coordinate axis, for all columns And obtaining the first angle as an average value of the tilt angles for each column.
The invention according to claim 9 is the alignment method according to claim 8, wherein the partial unit element position detection step acquires a captured image of the predetermined range, and the captured image is used as a target image. A step of performing a pattern matching process for detecting a region that matches a reference image for the unit element acquired in advance, and specifying a plurality of regions detected in the pattern matching process as the plurality of partial unit elements, Obtaining a coordinate value representing a center position of a plurality of regions as a coordinate value of the partial unit element.
The invention of claim 10 is the alignment program according to claim 6 or claim 7, wherein the first angle calculation step is the plurality of partial unit elements detected in the partial unit element position detection step. For each partial unit element belonging to the same column in the repetitive pattern, based on the value for the second coordinate axis orthogonal to the first coordinate axis among the coordinate values in the orthogonal coordinate system for Using the coordinate values of at least two partial unit elements classified as belonging to the same column, and determining the tilt angle of the column with respect to the first coordinate axis for all columns, Obtaining the first angle as an average value of the tilt angles for the columns.
The invention according to claim 11 is the alignment program according to claim 10, wherein the partial unit element position detecting step acquires a captured image of the predetermined range, and the captured image is used as a target image. A step of performing a pattern matching process for detecting a region that matches a reference image for the unit element acquired in advance, and specifying a plurality of regions detected in the pattern matching process as the plurality of partial unit elements, Obtaining a coordinate value representing a center position of a plurality of regions as a coordinate value of the partial unit element.

According to the first to eleventh aspects of the invention, a workpiece formed with a two-dimensional repetitive pattern, such as a case where a large number of micro devices having the same shape and structure are integrally formed. Can be easily and accurately eliminated without setting an alignment marker point.

  In particular, according to the third to sixth aspects of the present invention, the angle correction is performed after the substantially central portion of the workpiece is made to coincide with the rotation center, so that the accuracy of the angle correction can be maintained at a certain level or more. Further, since the temporary center can be obtained as a point relatively close to the true center, the processing is facilitated when the true center is determined after the inclination correction.

  In particular, according to the fourth aspect of the present invention, the temporary center can be determined by simple arithmetic processing.

  In particular, according to the inventions of claims 5 to 7, the approximate center position of the repetitive pattern is determined as the true center, and alignment is performed so that the true center coincides with the rotation center position. It is possible to set machining conditions and machining ranges that take advantage of the symmetry of the arrangement.

<Overview of laser processing equipment>
FIG. 1 is a diagram showing a configuration of a laser processing apparatus 100 according to an embodiment of the present invention. The laser processing apparatus 100 emits a laser beam LB from the laser light source 1, reflects the laser beam LB with a half mirror 3 provided in the lens barrel 2, and then processes the workpiece S placed on the stage 5. It is an apparatus that performs ablation processing of the processing site by condensing the focusing lens 4 so as to focus on the site and irradiating the processing site. The operation of the laser processing apparatus 100 is realized by controlling the operation of each unit to be described later according to the program 10 when the program 10 stored in the storage unit 6m of the computer 6 is executed by the computer. A general-purpose personal computer (PC) can be used as the computer 6. The storage means 6m is constituted by, for example, a memory or a predetermined storage device, and plays a role of storing various data necessary for operating the laser processing apparatus, including alignment described later.

As the laser light source 1, it is preferable to use an Nd: YAG laser. Further, adjustment of the wavelength, output, and pulse width of the laser beam LB emitted from the laser light source 1 is realized by a controller 7 connected to the computer 6. When a predetermined setting signal is issued from the computer 6 to the controller 7, the controller 7 sets the irradiation condition of the laser beam LB according to the setting signal. In the present embodiment, the laser beam LB has a wavelength belonging to the wavelength range of 210 nm to 533 nm, and in particular, it is preferable to use the third harmonic (wavelength of about 355 nm) of the Nd: YAG laser. The pulse width can be selected from 5 nsec to 50 nsec. That is, the laser processing apparatus 100 according to the present embodiment performs processing using an ultraviolet repetitive pulse laser. The laser beam LB is irradiated by being focused to a beam diameter of about several μm by the condenser lens 4. Thus, the energy density in the irradiation of the laser beam LB is approximately ^{100J / cm 2 ~100kJ / cm 2} , the peak power density becomes approximately ^{1GW / cm 2 ~500GW / cm 2} .

  Laser focusing in the laser processing apparatus 100 is realized by fixing the workpiece S to the stage 5 and moving the lens barrel 2 in the height direction (z-axis direction). The movement (height adjustment) of the lens barrel 2 is realized by driving the vertical movement mechanism Mv and the lens barrel 2 provided on the vertical movement mechanism Mv so as to be movable up and down by the driving means 8 connected to the computer 6. Has been. Thus, a two-stage operation is possible, which is a coarse movement operation by driving the vertical movement mechanism Mv and a fine movement operation by raising and lowering the lens barrel 2 with respect to the vertical movement mechanism Mv. By responding to the driving signal, a speedy and highly accurate focusing operation is realized.

  FIG. 2 is a diagram exemplarily showing the structure of the upper surface side of the stage 5. A plurality of suction grooves 51 are provided concentrically on the upper surface of the stage 5 shown in FIG. 2, and suction holes 52 are provided radially at the bottom of the suction grooves 51. With the workpiece S placed on the upper surface of the stage 5, the suction means 9 such as a suction pump connected to the suction hole 52 and the pipes PL1 and PL2 is operated, whereby the workpiece S is moved. A suction force acts along the suction groove 51, and the workpiece S is fixed to the stage 5. In addition, in the case where the workpiece S is divided after processing such as a semiconductor substrate, it is fixed via a predetermined expanding tape. As a result, even for a workpiece having a warp such as a workpiece in which a compound semiconductor is epitaxially grown on a sapphire substrate, the unevenness difference due to the warp is within the allowable range of the focal position of the laser beam LB. If it is about a degree, processing is possible.

  The stage 5 is formed of a material that is substantially transparent to the wavelength of the laser beam LB, such as quartz, sapphire, gallium nitride, or quartz. As a result, the laser beam LB transmitted through the workpiece and the laser beam irradiated off the workpiece (referred to as “excess laser beam”) are not absorbed by the surface of the stage 5, so that the excess laser beam Stage 5 is not damaged.

  Furthermore, the stage 5 is provided on the horizontal movement mechanism Mh. The horizontal movement mechanism Mh is driven horizontally in the XY2 axis direction by the action of the driving means 8. In the present embodiment, these X axis and Y axis are coordinate axes defined as reference coordinates having a certain machine origin position as the origin, and a plane defined by these two axes is referred to as a reference coordinate plane. .

  In addition, for the stage 5, a rotation (θ rotation) operation in the horizontal plane around the rotation axis determined so as to pass through the center position of the observation field of view by the CCD camera 16 is also realized independently of the horizontal drive. That is, during the rotation operation, rotation about the center of the observation field is always realized regardless of the position of the stage 5. In the following description, when simply referred to as “rotation center”, it indicates the position through which the rotation axis passes when the rotation is performed with the center of the observation field of view as the axis. In the present embodiment, an xy coordinate axis is given with a specific position on the reference coordinate plane as an origin, and the positive direction of the angle θ is the clockwise direction with the positive x-axis direction being the 0 ° position. And Further, the rotation axis direction is the z axis. That is, the xyz coordinate system is defined as an orthogonal coordinate system that is fixed relative to the reference coordinates.

  The drive means 8 drives the horizontal movement mechanism Mh in response to a drive signal from the computer 6, whereby the alignment of the workpiece S can be realized, and the predetermined workpiece site is moved to the irradiation position of the laser beam LB. Can do. At the time of processing, the laser beam LB can be scanned relative to the workpiece S.

  On the other hand, when processing, the processing by-product such as particles generated by re-solidification after the material at the processing site is melted or evaporated or scattered as a solid is generated on the surface of the workpiece S. It becomes a factor which pollutes a condensing lens. Therefore, in the laser processing apparatus 100 according to the present embodiment, the dust collection head 11 intended to remove such processing by-products is supported by the support 111 and attached to the lowermost part of the vertical movement mechanism Mv. .

  FIG. 3 is a view showing the dust collection head 11. FIG. 3A is a top view of the dust collection head 11 and the support 111, and FIGS. 3B and 3C are side views of the dust collection head 11. The dust collection head 11 includes a dust collection portion 112 having a flat plate-like and hollow structure, and an intake port 113 and an exhaust gas that are provided at an end and an upper portion of the dust collection portion 112 and communicate with the inside of the dust collection portion 112. It consists of a mouth 114.

  The dust collector 112 is provided so as to be positioned between the workpiece S and the condenser lens 4 provided at the lowermost part of the lens barrel 2. The dust collection portion 112 is provided with an upper opening 115 and a lower opening 116 above and below a position that becomes a central portion when viewed from above (FIG. 3B). Since the upper opening 115 and the lower opening 116 are provided so that the centers thereof coincide with the optical axis of the laser beam LB, the path of the laser beam LB is not blocked by the dust collection head 11. Further, since the dust collection head 11 is attached to the vertical movement mechanism Mv, the vertical movement mechanism Mv moves up and down, and the dust collection head 11, that is, the dust collection unit 112 also moves up and down. Since 2 can be moved up and down independently, the focus position of the laser beam LB is not limited by the arrangement of the dust collecting portion 112.

  The intake port 113 is connected to an inert gas supply means 12 provided as a utility in a factory or the like where the laser processing apparatus 100 is installed, for example, by a pipe PL3. The exhaust port 114 is connected to the exhaust unit 13 realized by, for example, an exhaust pump or the like by a pipe PL4. Filters 121 and 131 are provided in the middle of the pipes PL3 and PL4, respectively.

  The inert gas supply means 12 can supply an inert gas (for example, nitrogen gas) continuously. As indicated by the arrow AR1 (FIG. 1), the inert gas supplied from the inert gas supply means 12 is supplied from the intake port 113 to the dust collection part 112 as indicated by the arrow AR3 in the dust collection head 11, and is then exhausted. As shown by arrows AR2 (FIG. 1) and AR4, the exhaust is exhausted through the exhaust port 114. Therefore, an inert gas flow from the intake port 113 to the exhaust port 114 is generated in the dust collection portion 112 as indicated by an arrow AR5. In association with this, for example, the upper opening 115 and the lower opening 116 are provided. Since the attractive pressure is generated in the vicinity, the particles 117 existing in the vicinity are drawn into the dust collecting section 112 and are discharged from the exhaust port 114 together with the inert gas as indicated by the arrow AR6. By such an aspect, processing by-products such as particles generated by laser processing are prevented from adhering to the surface of the workpiece S or the condensing lens 4, and a reduction in processing efficiency is prevented. In other words, the inert gas acts as an assist gas during processing.

  Alternatively, as shown in FIG. 3 (c), for example, the upper opening 115 is detachably covered with a lid plate material 118 made of a material transparent to the laser beam LB, such as quartz, thereby condensing light. A mode of preventing adhesion of particles to the lens 4 may be adopted.

  Returning to FIG. 1, description will be given of components provided in the laser processing apparatus 100 for performing alignment of the workpiece S, positioning of the processing portion, and knowing the state during processing. For these purposes, the laser processing apparatus 100 is provided in the lens barrel 2 for reflecting the illumination light source 14 and the illumination light IL emitted from the illumination light source 14 to irradiate the workpiece S. The half mirror 15, the CCD camera 16 provided above the lens barrel 2 for imaging the surface of the workpiece S, the real-time observation image (monitor image) obtained by the CCD camera 16, and the image data in the storage means 6m. And a monitor 17 for displaying various processing menus and the like. The CCD camera 16 and the monitor 17 are connected to the computer 6 and controlled by the computer 6. By providing these, while the state of the surface of the workpiece S is confirmed on the monitor 17, the alignment of the workpiece S and the positioning of the workpiece site are performed, or the state of the workpiece surface being processed is determined. It is possible to know.

<Alignment in laser processing equipment>
Next, an alignment method for processing the workpiece S in the laser processing apparatus 100 according to the present embodiment, in particular, the workpiece S1 having a disk shape, on which the workpiece S is formed. A description will be given of a method for aligning repeated patterns in the case where repeated patterns having the same shape are formed. Here, the disk shape means that the workpiece S1 is almost a perfect circle, or a shape in which a part of the perfect circle is missing like a single crystal substrate having an orientation flat (orientation flat). Is meant to include.

  The alignment referred to here means that the position serving as the reference point of the repetitive pattern formed on the workpiece S1 to be processed placed on the stage 5 is coincident with the center of rotation, and 2 of the repetitive pattern. This means processing for canceling the in-plane tilt of the workpiece S1 so that the direction of the dimensional array coincides with the XY2 axis direction which is the horizontal driving direction of the stage.

  In the following description, the reference point of the repetitive pattern is referred to as “true center” and the position is referred to as “true center position”. As a rule, the true center is the intersection of the streets. The true center preferably coincides with the geometric center of the repetitive pattern, but this is not an essential requirement. Even if the true center is determined at a position shifted by several cycles at the maximum, the subsequent processing process Although some yield loss may occur depending on the setting, there is no practical problem.

  FIG. 4 is a diagram showing the main procedure of the alignment method. The alignment method according to the present embodiment includes a temporary center setting step (step S100), a rough angle correction step (step S200), a fine angle correction step (step S300), and a true center detection step (step 400). It is the method of including. Processing in each process is realized by the computer 6 controlling the operation of each unit of the laser processing apparatus 100 by executing the program 10 stored in the computer 6.

  The temporary center setting step refers to a position that is considered to be relatively close to the position prior to detection of the true center position by a simple method, preferably a method that uses the geometric characteristics of the workpiece S. This is a step of defining the temporary center and matching the position of the temporary center with the rotation center.

  The rough angle correction step is a method of roughly detecting the tilt angle (coarse angle) of the workpiece S1 whose temporary center has been determined by the temporary center setting step by a simple method, and tilting by the coarse angle. This is a step of performing correction (coarse angle correction) to eliminate.

  The precision angle correction step is a process of precisely obtaining the inclination angle (precision angle) of the workpiece S1 that has been subjected to the coarse angle correction, and performing correction (precise angle correction) to eliminate the inclination by the precision angle. It is a process. The workpiece S1 is not inclined by the precise angle correction.

  The true center detection step is a step of detecting the true center of the workpiece S1 after the precision angle correction and matching the true center position with the rotation center.

  Hereinafter, the alignment realized through these steps will be described by taking as an example the case where the workpiece S1 having an orientation flat is placed on the stage 5 as shown in FIG. Now, it is assumed that the workpiece S1 is placed at an angle α with respect to the horizontal direction (x-axis direction). Note that some positioning mark may be provided on the stage 5 in order to limit the placement position of the workpiece S1 within a certain range. In such a case, the deviation of the center position and the tilt angle are expected to fall within a certain error range, so that it is assumed that there will be fewer problems in alignment.

<Temporary center setting>
FIG. 6 is a diagram illustrating a process flow of the temporary center setting process. Here, since the workpiece S1 has a circular shape, the center position of the circle (or arc) is defined as a temporary center. This is because the repetitive pattern is generally provided such that its center (true center) substantially coincides with the center of the circle (arc). And here, the coordinates of three points on a circle (arc) are obtained, vertical bisectors are obtained for any two of the three line segments connecting any two points, and further their intersections are obtained. In this way, the coordinates of the temporary center are determined.

  First, the stage 5 is moved by a predetermined distance in the + Y direction, and the observation position by the CCD camera 16 is moved to the upper end portion of the workpiece S1 (step S101). In this case, at least the upper end portion only needs to be in the observation field of view of the CCD camera 16. Such movement may be such that the operator of the laser processing apparatus 100 searches for the upper end portion while viewing the image acquired by the CCD camera 16 displayed on the monitor 17, and the center position of the observation visual field before the movement is true. If it is not extremely different from the center position and the size of the workpiece S1 (distance between the true center position and the upper end) is known in advance, it is automatically moved by that size. There may be.

  When the movement to the upper end is made, the upper end position is specified based on the observation image at that position, and the xy coordinate value is acquired (step S102). In FIG. 5, it is assumed that the point E1 is the upper end position. The upper end position can be specified, for example, by using a known edge detection method from the distribution state of the color density value of each pixel in the observation image.

  When the upper end position coordinates are acquired, the observation position by the CCD camera 16 is subsequently moved to the left end portion of the workpiece S1 (step S103), and the observation image at that position is determined in the same manner as when the upper end position is specified. Based on the above, the left end position is specified, and its xy coordinate value is acquired (step S104). In FIG. 5, it is assumed that the point E2 is the left end position. Further, the observation position by the CCD camera 16 is moved to the right end portion of the workpiece S1 (step S105), and similarly to the above, the right end position is specified based on the observation image at the position, and the xy coordinate value is determined. Is acquired (step S106). In FIG. 5, it is assumed that the point E3 is the right end position.

When the above three points E1 to E3 are obtained, a perpendicular bisector l1 of the line segment E1E2 connecting the point E1 as the upper end position and the point E2 as the left end position is obtained (step S107), and further, the upper end position. A vertical bisector l2 of the line segment E1E3 connecting the point E1 and the point E3 which is the right end position is obtained (step S108). And when the intersection of these two perpendicular bisectors is calculated | required, this intersection is nothing but the center position of the circle | round | yen (arc) which the periphery of workpiece S1 makes. That is, the coordinates of the temporary center position C are obtained (step S109). For example, when the coordinates of E1, E2, and E3 are given as (ex1, ey1), (ex2, ey2), and (ex3, ey3), the vertical bisectors l1 and l2 are respectively
11: y = {(ey2-ey1) / (ex2-ex1)} (x-ex1) + ey1 (formula 1);
l2: y = {(ey3-ey1) / (ex3-ex1)} (x-ex1) + ey1 (Formula 2);
Therefore, the coordinate value of the temporary center position C can be obtained by combining these.

  When the temporary center position C is determined, the stage 5 is moved so that the coordinate position is at the center of the observation field, that is, the temporary center position C is positioned at the rotation center position (step S110). . This completes the provisional center setting step. FIG. 7 is a diagram illustrating the vicinity of the temporary center position C after completion of the temporary center setting process for the workpiece S1. In FIG. 7, only a part of the pattern is shown for convenience of illustration. As is the case with FIG. 7, the temporary center position C and the true center position C0 usually do not coincide with each other when the temporary center setting process is completed.

  Note that this position is not used as the true center position as it is, but the temporary center position is used when the workpiece S1 cannot always be regarded as a circle (arc), such as when there is a chip on the edge, or the pattern and the center position of the substrate. This is to prevent the obtained center position from greatly deviating from an appropriate position as the true center when the matching accuracy is not guaranteed. In particular, when a micro device such as a short wavelength LD or LED is formed on a sapphire substrate or the like using a semiconductor thin film such as GaN, the matching accuracy between the pattern and the center position of the substrate may not be sufficient.

<Coarse angle correction>
FIG. 8 is a diagram illustrating a processing flow of the rough angle correction process. In the rough angle correction step, the position of each unit element (pattern for one cycle) constituting the same-shaped repetitive pattern formed on the workpiece S1 is specified by a so-called pattern matching process, and the arrangement 1 Alternatively, the inclination angle is obtained with respect to a plurality of straight lines, and rough inclination correction is performed with the value of the inclination angles (or the average of the angles when obtained with respect to the plurality of straight lines). That is, the coarse angle correction step is a step of performing correction by regarding the inclination of the repetitive pattern as the inclinations of a plurality of columns formed by the unit elements constituting the pattern.

Here, the pattern matching process, a certain target image (e.g., repeated pattern image) match from among the reference image (for example, one unit of the image of the repeat) and images the contents that are represented in the region This is a process for detecting. In the present embodiment, a known technique such as disclosed in Patent Document 1 can be used for the pattern matching process.

  First, image data of a reference image (first reference image REF1) used when performing pattern matching is acquired (step S201). For example, the first reference image REF1 may be obtained by extracting an image of a region corresponding to a unit element from an observation image of the workpiece S1 after detection of the temporary center position as illustrated in FIG. Alternatively, it may be obtained in advance from device design data or the like.

  Next, an image of a region including the temporary center position C is acquired as a first matching target image OBJ1 as a pattern matching target image (step S202). Then, pattern matching processing (primary pattern matching) is performed with the first reference image REF1 (step S203). In order to ensure matching accuracy, it is preferable that the first matching target image OBJ1 and the first reference image REF1 are images of equal magnification.

  FIG. 9 is a diagram illustrating a result of performing pattern matching processing on the first matching target image OBJ1. In the primary pattern matching, as shown in FIG. 9, in the first matching target image OBJ1, the frame FR having the same size as the reference image REF1 is shifted pixel by pixel, and the obtained region image and reference image are obtained each time. The matching frequency (predetermined frequency representing the degree of matching between the reference image and the target image calculated in the used pattern matching process) is obtained. Then, an area having a matching frequency equal to or higher than a predetermined threshold is determined to be an area having a shape that matches the shape of the unit element indicated by the reference image REF1, that is, a matching area. From the viewpoint of matching accuracy, pattern matching processing using normalized correlation is preferable.

  Each of the matching regions thus obtained is at least a part of the unit elements that form a repeated pattern on the workpiece S1. In FIG. 9, all 61 matching regions R1 to R61 obtained in this way are each surrounded by a rectangular frame. In the present embodiment, the position of the center of the rectangular frame (intersection of diagonal lines) is defined as the position of each region, which is referred to as matching positions P1 to P61. Data of each matching position is stored in the storage unit 6m.

  Then, as in the case of FIG. 9, when two or more matching regions are obtained (YES in step S204), the data of each matching position P1 to P61 is sorted by the y coordinate value (step S205), Based on the results, the matching positions are grouped (step S207). FIG. 10 is a diagram showing y-coordinate values with a number line for some of the matching positions P1 to P18 in order to explain such grouping. That is, the number line shown in FIG. 10 corresponds to (part of) the mapping of each matching position to the y coordinate in FIG.

  The grouping performed here means one or a plurality of units having the same inclination as the repetitive pattern depending on what positional relationship each unit element obtained as each matching region R1 to R61 has and what combination This is a process performed to determine whether to form a sequence of elements. In the case of the repetitive pattern shown in FIG. 9, it can be understood that the unit elements generally form a plurality of columns in the horizontal direction (x-axis direction) of the drawing. By looking at the relationship between the y coordinate values, it is possible to determine which unit elements form a column.

  Specifically, as in the repeated pattern shown in FIG. 9, when the inclination degree is relatively small, for example, when the inclination angle is in a range of about ± 5 °, the same column is usually formed. Compared with the difference in y coordinate values between unit elements, the difference in y coordinate values between unit elements belonging to different columns is sufficiently large. In such a case, if the difference between the y coordinates of two matching areas is significantly larger than the difference between the y coordinates of the other matching areas, it can be determined that they belong to different columns. It is. When placing the workpiece S1 on the stage 5, it is possible to suppress the inclination generated in the repetitive pattern to such an angle range by placing it while taking into consideration that the repetitive pattern is not inclined as much as possible. This is even easier if there is a positioning mark as described above. As a reference value for the difference between the y-coordinate values, for example, use of the unit element size (or the pitch of the repetitive pattern) u may be considered.

  In the case of FIG. 9, as shown in FIG. 10, the difference Δy6 between the y coordinate values of the matching regions R6 and R7 is significantly larger than the difference between the y coordinate values of the matching regions R1 to R6. Moreover, it is (DELTA) y6-u. Therefore, it is determined that the matching regions R1 to R6 and the matching region R7 correspond to unit elements belonging to different columns. Similarly, that is, the unit elements obtained as the matching regions R1 to R6 belong to a certain column. Similarly, the matching regions R7 to R15, R16 to R18, R19 to R26, R27 to R34, R35 to R39, R40 to R48, R49 to R53, and R54 to R61 are determined to belong to one column. Become. That is, unit elements detected as matching regions are classified into nine groups in total. Here, as shown in FIG. 9, it is assumed that each group is identified by attaching a group number in order from the smallest y coordinate.

  When such grouping is performed, it is determined whether or not the number of matching for the I-th group, that is, the number of matching regions belonging to the group is 2 or more, with 1 as an initial value (steps S207 and S208).

When the number of matching for the I-th group is 2 or more (YES in step S208), the group is counted as an effective group for coarse angle correction (step S209). In such a case, it is possible to uniquely determine a straight line representing an array formed by the matching regions belonging to the group. Now, the equation of the straight line L _I for the I-th group is
L _I : y = xtan θ _I + B _I (Formula 3);
It can be expressed as.

In the present embodiment, for the sake of simplicity of processing, a straight line passing through the matching positions of two matching regions where the difference between the values of the x coordinate values is the largest among the matching regions belonging to the same group is defined as the straight line L _I. , Calculate its slope. For example, no. In the case of one group, the slope of a straight line passing through P1 (x1, y1) and P6 (x6, y6) is obtained.
tanθ _I = (y6-y1) / (x6-x1) (Formula 4);
This relationship holds. From this, the inclination angle θ _{I of the} straight line is
θ _I = tan ⁻¹ {(y6-y1) / (x6-x1)} (Formula 5);
(Step S210).

The same processing is performed for all groups (steps S211 and S212). As a result, when there is one or more effective groups (YES in step S213), the inclination angle θ _I obtained for each straight line is calculated. By averaging, the rough correction angle θ _r is obtained (step S214).

Then, the workpiece S1 is rotated by the rough correction angle θ _{r in the} direction to eliminate the inclination with the temporary center position C as the rotation center (step S215). Thereby, the inclination of the repeated pattern is almost eliminated. When such rotation processing is performed, the coarse angle correction ends.

  As a result of the primary pattern matching process, an effective group is obtained when the number of matching regions is one or zero (NO in step S204), and when only one matching region is detected for each column, for example. If not (NO in step S213), the subsequent processing cannot be continued, and the process ends in error (step S216).

<Precise angle correction>
Although the initial inclination of the workpiece S1 is substantially eliminated by the rough angle correction step, the rough angle correction is merely based on the state near the center of the workpiece S1. Since the tilt error appears more conspicuously as the distance from the rotation center increases, a precise angle correction step is performed for the purpose of confirming the tilt degree at the end of the workpiece S1 and correcting the tilt as necessary.

  FIG. 11 is a diagram showing the flow of processing in the precision angle correction process. The fine angle correction is a process in which pattern matching is performed in the vicinity of the temporary center position and the end of the workpiece after the coarse angle correction, and the slight remaining inclination is corrected based on the result. FIG. 12 is a diagram for explaining the precise angle correction. Now, after the rough angle correction, it is assumed that the workpiece S1 is inclined by an angle β (β << α) as shown in FIG.

  First, image data of a reference image (second reference image REF2) used when performing pattern matching is acquired (step S301). FIG. 12A is a diagram illustrating the second reference image REF2. For example, the second reference image REF2 may be obtained by extracting an image of a region corresponding to a unit element from the observation image of the workpiece S1 after the coarse angle correction, or device design data It may be an aspect obtained in advance from the above.

  Next, an image of a region including the temporary center position C is acquired as a second matching target image OBJ2 as a pattern matching target image (step S302). The second matching target image OBJ2 in the secondary pattern matching may be an image in the temporary center position and the vicinity thereof, specifically, an image in the same range as the second reference image REF2. However, in order to ensure matching accuracy, it is preferable that the second matching target image OBJ2 and the second reference image REF2 are images of equal magnification. Note that even if the repeated pattern has an inclination of the angle β, the value is very small, so that the repeated pattern is observed to be hardly inclined near the temporary center.

  Then, pattern matching processing (secondary pattern matching) is performed with the second reference image REF2 (step S203). Similar to the primary pattern matching, the pattern matching process can be performed by a known method.

  As a result of the secondary pattern matching, if the number of matching is one, the matching position (now referred to as the central matching position M) is specified for the matching area in the same manner as described above, and the coordinate value is stored in the storage means 6m. Store (YES in step S304, S305).

  In many cases, as shown in the enlarged matching target image OBJ2 in FIG. 12B, the matching region obtained as a result of the secondary pattern matching includes the temporary center position C. Even if not, the positions of both are considered to be relatively close.

  Thereafter, in order to continue pattern matching at the end of the workpiece S1, the observation field of view is moved to the end. However, the movement distance in such movement is appropriately determined so as to be a distance that is a natural number multiple of the unit element size u in the positive x-axis direction from the temporary center position (step S306). As a result, in the case shown in FIG. 12B, the observation field of view moves to a place including a position C ′ that is a distance Δx = k · u (k is a natural number) from the temporary center position C in the positive x-axis direction. Will be. As illustrated in an enlarged view in FIG. 12B, although the inclination of the repeated pattern is almost canceled by the coarse angle correction, it is inclined by the angle β. The inclination is remarkably confirmed.

  At this position, the third matching target image OBJ3 is acquired, and tertiary pattern matching is performed using the second reference image REF2 as a reference image (steps S307 and S308). If the number of matching is one as a result of the tertiary pattern matching, a matching position (this is referred to as an end matching position M ′) is specified for the matching area in the same manner as described above, and the coordinate value is stored in the storage unit 6m. (YES in step S309, S310).

As described above, when the center matching position M and the end matching position M ′ are obtained, the straight line L _f passing through both can be uniquely determined. Now, the equation of the straight line L _f is
L _f : y = xtan θ _f + B _f (Formula 6);
It can be expressed as.

Here, if the coordinates of the center matching position M and the end matching position M ′ are (xm1, ym1) and (xm2, ym2), respectively,
tanθ _f = (ym2-ym1) / (xm2-xm1) (Formula 7);
This relationship holds. From this, the inclination angle θ _{f of the} straight line is
θ _f = tan ⁻¹ {(ym2-ym1) / (xm2-xm1)} (Equation 8);
Therefore, the angle θ _f is set as a precision correction angle (step S311).

Then, the observation field of view is returned so that the temporary center position C coincides with the rotation center, and is rotated by the precision correction angle θ _{f in a} direction to eliminate the inclination β (step S312). Since it can be assumed that θ _f ≈β, the inclination of the repetitive pattern is canceled out precisely. With this rotation processing, the precise angle correction ends.

  In addition, when the result of the secondary pattern matching process is other than one matching area (NO in step S304), and when the result of the secondary pattern matching process is other than one matching area (NO in step S309), Since the subsequent processing cannot be continued, the process ends in error (step S313).

<True center detection>
When the precise angle correction is completed, the repeated pattern has no inclination, and therefore the true center position can be moved to the center of rotation by performing an appropriate translation operation. After all, the true center detecting step is a step of performing such a translation operation. FIG. 13 is a diagram illustrating a process flow of the true center detection process. FIG. 14 is a diagram for explaining the true center detection process.

  In the true center detection step, first, a fourth matching target image is acquired near the temporary center, and quaternary pattern matching is performed (steps S401 and S402). In the quaternary pattern matching, the same image data as the second reference image REF2 may be used as the fourth reference image REF4. However, the fourth reference image REF4 is an image in a range of at least about one unit element cycle + α, and the true center position formed on the workpiece S1 and at least one unit element closest thereto. It is necessary that the positional relationship with the center, that is, the relative position coordinate between the two is an image obtained as a known one. In the case of the fourth reference image REF4 shown in FIG. 14A, the point Q1 is a point corresponding to the former, that is, the true center position, and the point Q2 is a point corresponding to the latter. In other words,

Needs to coincide with a vector connecting the true center position and the center of the unit element closest to the true center position, and its components must be known. In addition, the aspect which acquires separately the image different from 2nd reference image REF2 as a reference image may be sufficient.

  As a result of the quaternary pattern matching, at least one matching region is usually obtained (YES in step S403). For example, in the case of quaternary pattern matching between the fourth reference image REF4 shown in FIG. 14A and the fourth matching target image OBJ4 shown in FIG. 14B, the point Q1 and the matching position N correspond to each other. Therefore, the position corresponding to the point Q2 is determined as the true center position C0. If no matching area is obtained, the subsequent processing cannot be continued, and the process ends with an error (NO in step S403, S406).

  On the other hand, at the time when quaternary pattern matching is performed, the temporary center position is usually located within or very close to the matching region. For example, in the case of the fourth target image OBJ4, the temporary center position C is located in the vicinity of the matching position N.

  Now, in order to position the true center at the center of rotation instead of the temporary center, that is, at the center of the observation field, the true center is translated from the current true center position C0 to the temporary center position C (rotation center position). Can be calculated for each coordinate axis. As shown in FIG. 14 (c), this is, after all, a vector connecting both points,

It is only necessary to obtain the following components. However, in FIG. 14C, point A is the origin of each position vector. Now, from the correspondence between the fourth reference image REF4 and the fourth matching target image OBJ4,

Because

It can be expressed as. Since all the vectors on the rightmost side are already known, the amount of movement of the stage 5 for matching the true center with the rotation center, in other words, the relative position of the true center with respect to the temporary center is obtained ( Step S404).

  Therefore, by moving the stage 5 according to the obtained movement amount, the true center coincides with the rotation center (step S405). With this movement, true center detection ends. Then, when the true center is detected in this way, the alignment according to the present embodiment is completed. When such alignment is performed, the process proceeds to a predetermined processing process using the laser beam LB.

  As described above, when the alignment method according to the present embodiment is used, the workpiece S is a workpiece S1 having a disk shape like a single crystal substrate, and the same shape is repeatedly formed thereon. When a pattern is formed, alignment can be performed easily and accurately without setting marker points for alignment on the pattern.

<Modification>
Since the repetitive pattern is formed in a lattice pattern, the step of determining the temporary center and positioning it at the center of rotation is not essential if the inclination is simply corrected. Therefore, in a state where an arbitrary position is the rotation center, the same rough angle correction as described above is performed, and further, by obtaining the inclination of a straight line passing through the two points of the rotation center position and a position sufficiently away from the rotation center position, It is also possible to perform precise angle correction in the same manner as described above. However, if the inclination is corrected once the temporary center is determined as in the above-described embodiment, the correction is always performed after the rotation center is determined based on the same reference. It is considered that the accuracy (reproducibility) can be kept above a certain level. Therefore, in particular, when the workpiece has a disk shape, the aspect in which the inclination is corrected after the provisional center is determined as in the above-described embodiment is preferable from such a viewpoint.

  In the above embodiment, when performing the coarse angle correction, the inclination of the array of unit elements is calculated as the inclination of a straight line passing through two points as shown in (Equation 4). Alternatively, it may be calculated by the least square method.

  When the work piece is disk-shaped, in obtaining the temporary center, instead of obtaining the intersection of the perpendicular bisectors of the strings as described above, the coordinate values of the three points on the circumference are the same. It may be a mode to be obtained from the condition that the equation of the circle is satisfied.

  In the precise angle correction step, if the y coordinate difference between the center matching position M and the end matching position M ′ is almost equal to 0, it is determined that there is almost no inclination without performing precise angle correction. It is also possible to cancel the precise angle correction.

  In the above-described embodiment, the precise angle correction is performed using the center and the end of the workpiece. However, the greater the distance between the two points that determine the coordinate position, the more accurate the correction. Will improve. Therefore, when performing the secondary pattern matching in the precision angle correction process, the distance Δx = m · u (m may be a natural number and m = k) may be separated from the temporary center position C in the negative x-axis direction instead of the temporary center position C. A mode in which pattern matching is performed at a position, and angle correction is performed based on the slope of a straight line passing through the coordinate position obtained as a result and the coordinate position obtained by subsequent tertiary pattern matching may be employed. .

  The pattern matching has been described in the form of determining whether or not to match a figure for one period of a repetitive pattern, but may be an aspect for determining matching with a figure for a plurality of periods. If matching is performed using a figure for one period, for example, the smaller the device, the higher the magnification image that needs to be obtained, and the higher the height position accuracy is. If matching is performed using graphics, it is possible to cope with miniaturization of devices while maintaining matching accuracy.

It is a figure which shows the structure of the laser processing apparatus 100 which concerns on embodiment of this invention. It is a figure which shows the structure of the upper surface side of the stage 5 exemplarily. It is a figure which shows the dust collection head. It is a figure which shows the main procedures of the alignment method which concerns on this Embodiment. It is a figure which illustrates the to-be-processed object used as alignment object. It is a figure which shows the flow of a process of a temporary center setting process. It is a figure which illustrates the neighborhood of temporary center position C after the end of temporary center setting process. It is a figure which shows the flow of a process of a rough angle correction process. It is a figure which illustrates the result of having performed the primary pattern matching process. It is a figure for demonstrating grouping of a matching position. It is a figure which shows the flow of a process of a precision angle correction process. It is a figure for demonstrating precision angle correction | amendment. It is a figure which shows the flow of a process of a true center detection process. It is a figure for demonstrating a true center detection process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser light source 2 Lens barrel 3 Half mirror 4 Condensing lens 5 Stage 6 Computer 6m Storage means 7 Controller 8 Driving means 9 Suction means 10 Program 14 Illumination light source 15 Half mirror 16 Camera 17 Monitor 100 Laser processing apparatus C Temporary center position C0 True Center position IL Illumination light LB Laser light Mh Horizontal movement mechanism Mv Vertical movement mechanism R1-R61 Matching region P1-P61 Matching position S, S1 Workpiece

Claims (11)

In a processing apparatus that performs processing using a light beam emitted from a predetermined light source as a processing means , a plurality of devices having the same shape and structure are integrally formed so that a plurality of unit elements having the same shape are repeatedly formed on the surface. A method of aligning the workpiece when performing a process of cutting a workpiece in which a pattern is formed two-dimensionally for each unit element ,
a) a workpiece holding step of holding the workpiece by a predetermined holding means so as to be rotatable in a plane with respect to a predetermined reference coordinate plane;
b) a coarse angle correction step for roughly correcting the inclination of the repetitive pattern in the reference coordinate plane; and c) a precision for precisely correcting the inclination of the repetitive pattern in the reference coordinate plane after the rough angle correction step. An angle correction process;
With
The rough angle correction step includes
b-1) Coordinates in a predetermined orthogonal coordinate system in which arrangement positions of a plurality of partial unit elements included in a predetermined range among the unit elements forming the repetitive pattern are fixed relative to the reference coordinate plane A partial unit element position detection step to detect as a value;
b-2) a first angle for calculating a first angle formed by a first straight line representing the arrangement direction of the plurality of partial unit elements with a first coordinate axis of the predetermined orthogonal coordinate system based on the coordinate value; An angle calculation step;
b-3) a first rotation step of rotating the workpiece in a direction in which the inclination of the repetitive pattern with respect to the first coordinate axis is eliminated, with the first angle as a rotation angle;
With
The precise angle correction step includes
c-1) End position specification for specifying an arrangement position of one unit element existing at an end position separated from the rotation center position in the rotation step by an integral multiple of the unit element in the first coordinate axis direction Process,
c-2) calculating a second angle formed by a second straight line connecting the rotation center position and the arrangement position of the one unit element obtained in the end position specifying step with the first coordinate axis; A second angle calculating step;
c-3) a second rotation step of rotating the workpiece in a direction in which the inclination of the repetitive pattern with respect to the first coordinate axis is eliminated with the second angle as a rotation angle;
An alignment method in a laser processing apparatus, comprising: In a processing apparatus that performs processing using a light beam emitted from a predetermined light source as a processing means , a plurality of devices having the same shape and structure are integrally formed so that a plurality of unit elements having the same shape are repeatedly formed on the surface. A method of aligning the workpiece when performing a process of cutting a workpiece in which a pattern is formed two-dimensionally for each unit element ,
a) a workpiece holding step of holding the workpiece by a predetermined holding means so as to be rotatable in a plane with respect to a predetermined reference coordinate plane;
b) a coarse angle correction step for roughly correcting the inclination of the repetitive pattern in the reference coordinate plane; and c) a precision for precisely correcting the inclination of the repetitive pattern in the reference coordinate plane after the rough angle correction step. An angle correction process;
With
The rough angle correction step includes
b-1) Coordinates in a predetermined orthogonal coordinate system in which arrangement positions of a plurality of partial unit elements included in a predetermined range among the unit elements forming the repetitive pattern are fixed relative to the reference coordinate plane A partial unit element position detection step to detect as a value;
b-2) a first angle for calculating a first angle formed by a first straight line representing the arrangement direction of the plurality of partial unit elements with a first coordinate axis of the predetermined orthogonal coordinate system based on the coordinate value; An angle calculation step;
b-3) a first rotation step of rotating the workpiece in a direction in which the inclination of the repetitive pattern with respect to the first coordinate axis is eliminated, with the first angle as a rotation angle;
With
The precise angle correction step includes
c-1) First and second end positions that are separated from the rotation center position by an integral multiple of the unit element with respect to the first coordinate axis direction across the rotation center position in the rotation step. An end position specifying step for specifying an arrangement position of one unit element existing in
c-2) A second angle calculating step of calculating a second angle formed by a second straight line connecting the arrangement positions of the one unit element at the first and second end positions with the first coordinate axis. When,
c-3) a second rotation step of rotating the workpiece in a direction in which the inclination of the repetitive pattern with respect to the first coordinate axis is eliminated with the second angle as a rotation angle;
An alignment method in a laser processing apparatus, comprising: The alignment method according to claim 1 or 2,
d) a temporary center setting step for determining a temporary center of the repetitive pattern;
Further comprising
The temporary center setting step is a step performed prior to the rough angle correction step,
d-1) a temporary center specifying step of specifying the temporary center based on a geometric feature of the workpiece;
d-2) a first translational movement step in which the temporary center coincides with the rotation center;
With
In the partial unit element position detection step, the predetermined range is determined around the temporary center,
In each of the first and second rotation steps, the temporary center is used as a rotation center.
An alignment method in a laser processing apparatus. The alignment method according to claim 3,
The workpiece has a disc shape,
An alignment method in a laser processing apparatus, wherein, in the temporary center specifying step, an intersection of two perpendicular bisectors of two strings determined with respect to an outer circumference circle of the workpiece is determined as the temporary center. The alignment method according to claim 3 or 4, wherein:
e) a true center detection step of detecting a true center of the repetitive pattern;
Further comprising
The true center detection step includes
e-1) a relative positional relationship specifying step of specifying a relative positional relationship between an intersection of a street that can be the true center in the repetitive pattern and a unit element near the intersection;
e-2) a true center setting step for determining the true center based on the position of the unit element near the intersection, the position of the temporary center, and the relative positional relationship;
e-3) a second translational movement step of translating the workpiece so that the true center determined in the true center setting step coincides with the temporary center;
An alignment method for a laser processing apparatus comprising: Predetermined reference coordinates for a workpiece in which a plurality of devices having the same shape and structure are integrally formed so that a repetitive pattern of a plurality of unit elements having the same shape is two-dimensionally formed on the surface A processing apparatus that holds the workpiece by a predetermined holding means so as to be able to rotate in-plane within a plane, and performs processing for cutting the workpiece for each unit element using a light beam emitted from a predetermined light source as a processing means; A program for realizing alignment of the workpiece in the processing apparatus by being executed in a computer of control means for controlling
a) a temporary center setting step for determining a temporary center of the repetitive pattern;
b) a coarse angle correction step for roughly correcting the inclination of the repetitive pattern in the reference coordinate plane; and c) a precision for precisely correcting the inclination of the repetitive pattern in the reference coordinate plane after the rough angle correction step. An angle correction process;
d) a true center detection step of detecting a true center of the repetitive pattern;
Is a program for causing the computer to execute
The temporary center setting step includes
a-1) a temporary center specifying step of specifying the temporary center according to the geometric characteristics of the workpiece; a-2) moving the holding means by a predetermined horizontal driving means to A first translational movement step to coincide with the center of rotation;
With
The rough angle correction step includes
b-1) A predetermined fixed position relative to the reference coordinate plane with respect to the arrangement position of a plurality of partial unit elements included in a predetermined range centered on the temporary center among the unit elements forming the repetitive pattern A partial unit element position detection step of detecting as a coordinate value in the orthogonal coordinate system of
b-2) a first angle for calculating a first angle formed by a first straight line representing the arrangement direction of the plurality of partial unit elements with a first coordinate axis of the predetermined orthogonal coordinate system based on the coordinate value; An angle calculation step;
b-3) a first rotation step of rotating the repetitive pattern about the temporary center in a direction in which the inclination is eliminated by using the first angle as a rotation angle by a predetermined rotation driving unit;
With
The precise angle correction step includes
c-1) an end position specifying step for specifying an arrangement position of one unit element existing at an end position separated from the temporary center in the first coordinate axis direction by an integral multiple of the unit element;
c-2) calculating a second angle formed by a second straight line connecting the temporary center and the opposing position of the one unit element obtained by the end position specifying step with the first coordinate axis; A two-angle calculation step;
c-3) a second rotation step of rotating the repetitive pattern about the temporary center in the direction in which the inclination is eliminated by the second driving angle by the rotation driving means;
With
The true center detection step includes
d-1) a relative positional relationship specifying step of specifying a relative positional relationship between an intersection of a street that can be the true center in the repetitive pattern and a unit element near the intersection;
d-2) a true center setting step for determining the true center based on the position of the unit element in the vicinity of the intersection, the position of the temporary center, and the relative positional relationship;
d-3) a second translational movement step of translating the workpiece so that the true center determined in the true center setting step is located at a position where the temporary center is located by the horizontal driving means;
An alignment program in a laser processing apparatus, comprising: Predetermined reference coordinates for a workpiece in which a plurality of devices having the same shape and structure are integrally formed so that a repetitive pattern of a plurality of unit elements having the same shape is two-dimensionally formed on the surface A processing apparatus that holds the workpiece by a predetermined holding means so as to be able to rotate in-plane within a plane, and performs processing for cutting the workpiece for each unit element using a light beam emitted from a predetermined light source as a processing means; A program for realizing alignment of the workpiece in the processing apparatus by being executed in a computer of control means for controlling
a) a temporary center setting step for determining a temporary center of the repetitive pattern;
b) a coarse angle correction step for roughly correcting the inclination of the repetitive pattern in the reference coordinate plane; and c) a precision for precisely correcting the inclination of the repetitive pattern in the reference coordinate plane after the rough angle correction step. An angle correction process;
d) a true center detection step of detecting a true center of the repetitive pattern;
Is a program for causing the computer to execute
The temporary center setting step includes
a-1) a temporary center specifying step of specifying the temporary center according to the geometric characteristics of the workpiece; a-2) moving the holding means by a predetermined horizontal driving means to A first translational movement step to coincide with the center of rotation;
With
The rough angle correction step includes
b-1) A predetermined fixed position relative to the reference coordinate plane with respect to the arrangement position of a plurality of partial unit elements included in a predetermined range centered on the temporary center among the unit elements forming the repetitive pattern A partial unit element position detection step of detecting as a coordinate value in the orthogonal coordinate system of
b-2) a first angle for calculating a first angle formed by a first straight line representing the arrangement direction of the plurality of partial unit elements with a first coordinate axis of the predetermined orthogonal coordinate system based on the coordinate value; An angle calculation step;
b-3) a first rotation step of rotating the repetitive pattern about the temporary center in a direction in which the inclination is eliminated by using the first angle as a rotation angle by a predetermined rotation driving unit;
With
The precise angle correction step includes
c-1) First and second end positions that are separated from the rotation center position by an integral multiple of the unit element with respect to the first coordinate axis direction across the rotation center position in the rotation step. An end position specifying step for specifying an arrangement position of one unit element existing in
c-2) A second angle calculating step of calculating a second angle formed by a second straight line connecting the arrangement positions of the one unit element at the first and second end positions with the first coordinate axis. When,
c-3) a second rotation step of rotating the repetitive pattern about the temporary center in the direction in which the inclination is eliminated by the second driving angle by the rotation driving means;
With
The true center detection step includes
d-1) a relative positional relationship specifying step of specifying a relative positional relationship between an intersection of a street that can be the true center in the repetitive pattern and a unit element near the intersection;
d-2) a true center setting step for determining the true center based on the position of the unit element in the vicinity of the intersection, the position of the temporary center, and the relative positional relationship;
d-3) a second translational movement step of translating the workpiece so that the true center determined in the true center setting step is located at a position where the temporary center is located by the horizontal driving means;
An alignment program in a laser processing apparatus, comprising: An alignment method according to any one of claims 1 to 5,
The first angle calculating step includes:
Based on the values for the second coordinate axis orthogonal to the first coordinate axis among the coordinate values in the orthogonal coordinate system for the plurality of partial unit elements detected in the partial unit element position detecting step, the plurality Classifying the partial unit elements for each partial unit element belonging to the same column in the repeating pattern,
Using the coordinate values of at least two partial unit elements classified as belonging to the same column, the inclination angle of the column with respect to the first coordinate axis is obtained for all the columns, and the inclination angle for each column is determined. Obtaining the first angle as an average value;
An alignment method in a laser processing apparatus, comprising: The alignment method according to claim 8, wherein
The partial unit element position detection step includes:
Obtaining a captured image of the predetermined range;
Performing a pattern matching process for detecting a region matching a reference image for the unit element acquired in advance with the captured image as a target image;
Identifying a plurality of regions detected in the pattern matching process as the plurality of partial unit elements, and obtaining a coordinate value representing a center position of the plurality of regions as a coordinate value of the partial unit element;
An alignment method in a laser processing apparatus, comprising: An alignment program according to claim 6 or claim 7,
The first angle calculating step includes:
Based on the values for the second coordinate axis orthogonal to the first coordinate axis among the coordinate values in the orthogonal coordinate system for the plurality of partial unit elements detected in the partial unit element position detecting step, the plurality Classifying the partial unit elements for each partial unit element belonging to the same column in the repeating pattern,
Using the coordinate values of at least two partial unit elements classified as belonging to the same column, the inclination angle of the column with respect to the first coordinate axis is obtained for all the columns, and the inclination angle for each column is determined. Obtaining the first angle as an average value;
An alignment program in a laser processing apparatus, comprising: An alignment program according to claim 10, wherein
The partial unit element position detection step includes:
Obtaining a captured image of the predetermined range;
Performing a pattern matching process for detecting a region matching a reference image for the unit element acquired in advance with the captured image as a target image;
Identifying a plurality of regions detected in the pattern matching process as the plurality of partial unit elements, and obtaining a coordinate value representing a center position of the plurality of regions as a coordinate value of the partial unit element;
An alignment program in a laser processing apparatus, comprising:

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