JP7445852B2 - Dicing equipment and dicing method - Google Patents

Description

The present invention relates to a dicing apparatus and a dicing method, and more particularly to a dicing apparatus and a dicing method for dividing a work such as a wafer on which semiconductor devices or electronic components are formed into individual chips.

A dicing machine that divides a workpiece such as a wafer on which semiconductor devices or electronic components are formed into individual chips has a blade that is rotated at high speed by a spindle, a worktable that holds the workpiece by suction, and a connection between the worktable and the blade. It includes X, Y, Z, and θ drive units that change the relative position. In this dicing apparatus, dicing (cutting) is performed by cutting the workpiece with the blade while relatively moving the blade and the workpiece using each drive section.

In dicing equipment, it is an important element to match the depth of cut of the blade with the set value. To match the depth of cut of the blade with the set value, the positioning of the Z axis, which is the direction of cutting into the workpiece, must be repeated to achieve high precision. In addition, it is necessary to detect and correct blade wear.

For example, as described in Patent Document 1, in conventional Z-axis positioning, the blade is first brought into contact with the top surface of the work table to detect electrical continuity, and the center position of the blade at this time is used as a reference position to position the Z-axis. is under control. This operation of bringing the blade into contact with the top surface of the work table to detect electrical continuity is called cutter set. Further, the blade wear is corrected by bringing the blade into contact with the work table every time a set number of lines are processed to correct the reference position. However, since this method brings the blade into contact with the worktable, there is a risk of damaging the blade.

In order to solve the problem of this contact type cutter set, for example, an optical cutter set device is proposed in Patent Document 2. This optical cutter set device moves a blade in the Z-axis direction perpendicular to the optical axis between the light emitting means and the light receiving means, and gradually blocks the detected light with the blade until a preset amount of received light is reached. The blade is positioned based on the blade center position when the blade is rotated.

Japanese Patent Application Publication No. 2003-211350 Japanese Patent Application Publication No. 2003-234309

By the way, there are three types of blade dicing methods: half cut, semi-full cut, and full cut. In recent years, as workpieces have become larger in diameter, the full-cut method that completely cuts the workpiece has become mainstream. In the full cut method, the workpiece is attached to the dicing tape and placed on the worktable, and the blade cuts from the surface of the workpiece to the dicing tape while moving the blade and worktable relatively. into individual chips.

However, the above-mentioned conventional technology has a problem in that it cannot sufficiently cope with dicing that performs a full cut of a workpiece.

That is, in the case of the full cut method, it is necessary to control the depth of cut (amount of cut) of the blade so that the blade sufficiently penetrates the workpiece and does not reach the work table.

For example, as shown in FIG. 18, when a full cut is made on the work W, the height H of the blade 90 (height from the work table surface to the center position of the blade 90) is equal to the cutting depth D into the work W. is positioned so that it is larger than the thickness M of the workpiece W. Then, a work table (not shown) is cut and fed in the X direction with respect to the blade 90 rotated at high speed, so that one line of cutting grooves 92 is formed in the work W.

However, if there are undulations on the surface of the work table or if there are variations in the thickness of the dicing tape T, for example, as shown in FIG. In the thinner portion compared to , the depth of cut D1 into the workpiece W is smaller than the depth of cut D shown in FIG. 18 . That is, the blade 90 shallowly cuts the workpiece W. In this case, the blade 90 does not cut into the workpiece W sufficiently, which causes cutting defects.

On the other hand, as shown in FIG. 20, in a portion where the dicing tape thickness K2 is thicker than the dicing tape thickness K shown in FIG. 18, the cutting depth D2 into the work W is the cutting depth D shown in FIG. becomes larger than That is, the blade 90 makes a deep cut into the workpiece W. In this case, the blade 90 cuts into the dicing tape T more than necessary. Therefore, the blade 90 is likely to become clogged with the adhesive on the surface of the dicing tape, which causes the blade 90 to become less sharp. Alternatively, it may cause tape breakage or the like in the expanding process that is carried out after the dicing process.

In this way, even when the blade is set at a predetermined height, if there are variations in the thickness of the dicing tape, there will be variations in the depth at which the blade cuts into the dicing tape, resulting in stable processing quality. There may be problems that may occur. Note that similar problems occur not only due to variations in the thickness of the dicing tape, but also due to waviness of the surface of the work table, wear of the blade, etc.

Particularly in recent years, as the number of chips per wafer increases, the blade width of the blade tends to become thinner. As the width of the blade becomes thinner, the number of abrasive grains on the blade decreases accordingly, so the blade is more likely to become clogged with the adhesive on the surface of the dicing tape, and the above-mentioned problem becomes more pronounced.

The present invention has been made in view of the above circumstances, and provides a dicing device and a dicing device capable of stabilizing processing quality without being affected by waviness of the surface of the work table or variations in the thickness of the dicing tape. The purpose is to provide a dicing method.

In order to achieve the above object, the following invention is provided.

A dicing device according to a first aspect of the present invention is a dicing device that performs dicing by relatively moving a blade rotated by a spindle and a work table while holding a work to be processed on a work table via a dicing tape. The device includes a map creation unit that creates a calibration map showing the shape of the surface of the worktable from the measurement results of the surface shape of the calibration workpiece held on the worktable, and a blade determination workpiece using a blade. A blade shape determination unit that acquires an image of the groove formed on the surface of the workpiece and determines the blade tip shape from the image, and a blade shape determination unit that determines the blade tip shape when processing the workpiece based on the calibration map and the blade tip shape. and a control section that controls the height.

In the dicing apparatus according to a second aspect of the present invention, in the first aspect, the control unit determines the state of wear of the blade from the shape of the tip of the blade, and the more the wear progresses, the higher the height of the blade. make low.

The dicing apparatus according to the third aspect of the present invention, in the first or second aspect, further includes a cutting mark detection section that detects cutting mark information formed on the surface area of the dicing tape to which no workpiece is attached. The control unit controls the height of the blade so that the depth of cut into the dicing tape is constant based on the cutting mark information detected by the cutting mark detection unit.

In the dicing apparatus according to a fourth aspect of the present invention, in the third aspect, the cutting mark detection section calculates the cutting mark formation rate in the surface area of the dicing tape based on the cutting mark information, and the control section calculates the cutting mark formation rate in the surface area of the dicing tape. Based on the cutting mark formation rate calculated by the mark detection section, the height of the blade is controlled so that the cutting mark formation rate falls within a certain range.

A dicing method according to a fifth aspect of the present invention is a dicing method in which a workpiece to be processed is held on a worktable via a dicing tape, and dicing is performed by relatively moving a blade rotated by a spindle and a worktable. The method includes a calibration map creation step of creating a calibration map indicating the shape of the surface of the worktable from the measurement results of the surface shape of the calibration workpiece held on the worktable, and a blade determination process using a blade. The blade shape determination step involves acquiring an image of the groove formed on the surface of the workpiece and determining the tip shape of the blade from the image. and a control step for controlling the height of the blade.

In the dicing method according to the sixth aspect of the present invention, in the fifth aspect, the calibration work has a uniform thickness.

In the dicing method according to the seventh aspect of the present invention, in the fifth or sixth aspect, the blade determination workpiece has a mirror-finished surface or is a glass plate.

According to the present invention, processing quality can be stabilized without being affected by undulations on the surface of the work table or variations in the thickness of the dicing tape.

Schematic diagram showing the configuration of a dicing device according to this embodiment Plan view showing the workpiece Diagram showing an example of a calibration map A plan view showing the planar shape of the calf Table showing examples of blade height correction amounts for each blade tip shape determination result Schematic diagram showing how dicing is performed on a workpiece Schematic diagram showing how the imaging device images the dicing tape area Schematic diagram showing how the line sensor camera images the dicing tape area Diagram showing an example of a correction table Diagram showing a specific example of operation in this embodiment Diagram showing the trajectory of the tip (-Z side end) of the blade 18 Flowchart showing the flow of blade height correction operation Flowchart showing the calibration map creation process Flowchart showing the blade shape determination process Flowchart showing the dicing process Schematic diagram showing the configuration of a dicing device according to another embodiment Diagram showing an example of a height graph generated by the cutting mark detection unit Diagram to explain conventional problems Diagram to explain conventional problems Diagram to explain conventional problems

DESCRIPTION OF THE PREFERRED EMBODIMENTS A dicing apparatus and a dicing method according to embodiments of the present invention will be described below with reference to the accompanying drawings.

[Configuration of dicing device 10]
FIG. 1 is a schematic diagram showing the configuration of a dicing apparatus 10 according to this embodiment.

As shown in FIG. 1, the dicing apparatus 10 includes a work table 12, a sub-table 13, a θ table 14, an X table 16, a blade 18, a spindle 20, a Y table (not shown), and a Z table. (not shown), an imaging device 22, a displacement sensor 25, and a control device 50.

In this embodiment, before the dicing process, a calibration map that reflects the waviness of the surface of the work table 12 is created. Furthermore, before the dicing process, the shape of the tip of the blade 18 is determined. When performing the dicing process, the height of the blade 18 is adjusted so that the depth of cut into the dicing tape T is constant based on the calibration map, the determination result of the tip shape of the blade 18, and the cutting mark formation rate described below. control.

The X table 16 is provided on the upper surface of an X base (not shown). The X table 16 is configured to be movable in the X direction by an X drive unit (not shown) including a motor, a ball screw, and the like. A θ table 14 is placed on the X table 16, and a work table 12 is attached to the θ table 14. The θ table 14 is configured to be rotatable in the θ direction (rotation direction around the Z-axis) by a rotation drive unit (not shown) including a motor or the like.

The Y table is provided on the side surface of the Y base (not shown). The Y table is configured to be movable in the Y direction by a Y drive unit (not shown) including a motor, a ball screw, and the like. A Z table (not shown) is attached to the Y table. The Z table is configured to be movable in the Z direction by a Z drive unit (not shown) including a motor, a ball screw, and the like. A spindle 20 with a built-in high frequency motor and a blade 18 attached to the tip is fixed to the Z table.

With this configuration, the blade 18 is index-fed in the Y direction and cut-fed in the Z direction. Further, the work table 12 is rotated in the θ direction and fed for cutting in the X direction.

The spindle 20 is rotated at high speed, for example, from 30,000 rpm to 60,000 rpm.

The blade 18 is a thin disc-shaped cutting edge. As the blade 18, an electrodeposited blade in which diamond abrasive grains or CBN (Cubic form of Boron Nitride) abrasive grains are electrodeposited with nickel, a resin blade bonded with resin, or the like is used. Further, the dimensions of the blade 18 are variously selected depending on the processing contents, but when dicing a normal semiconductor wafer as a workpiece W, a blade having a diameter of 50 mm and a thickness of about 30 μm is used.

When creating a calibration map, the work table 12 holds the calibration workpiece by suction. As the calibration workpiece, it is preferable to use a workpiece having a uniform thickness (for example, a silicon wafer) and having a planar shape that is approximately the same as the workpiece W to be processed or larger than the workpiece W to be processed. . Note that the calibration work may be suction-held on the surface of the work table 12 while being attached to the same dicing tape T used for dicing the work W to be processed.

The displacement sensor 25 measures the shape (irregularities) of each position on the surface of the calibration work while the calibration work is suctioned and held on the work table 12 . As the displacement sensor 25, for example, a laser displacement sensor, an optical or contact displacement sensor, a TOF (Time of Flight) camera, or the like can be used. The displacement sensor 25 is movable relative to the work table 12. Note that the displacement sensor 25 may be attached to the Y table together with the spindle 20, or may be provided with a separate drive mechanism for moving the displacement sensor 25 in the XYZ directions.

Data on the surface shape of the calibration workpiece measured by the displacement sensor 25 is input to the map creation section 58 of the control device 50 . For example, the map creation unit 58 calculates the Z coordinate (actual measurement value) of each position on the surface of the work table 12 when the surface (design value) of the work table 12 is set to the XY plane (Z=0). Calibration map data is created and stored in the storage unit 54.

Next, determination of the tip shape of the blade 18 will be explained. When determining the shape of the tip of the blade 18, the blade 18 forms a groove in the blade determination workpiece W0 held by suction on the sub-table 13. Then, an image of this groove is captured by the imaging device 22, and the shape of the tip of the blade 18 is determined based on the planar shape of the groove.

The sub-table 13 is fixed near the work table 12 by a holding member (arm), and is movable integrally with the work table 12. The sub-table 13 holds the blade determination work W0 by suction.

The imaging device 22 is arranged at a position facing the work table 12. The imaging device 22 images the surface of the workpiece W in order to determine the shape of the tip of the blade 18, align the workpiece W, and evaluate the machining state (kerf check). Note that the imaging device 22 is an example of an imaging device (alignment camera) of the present invention.

The imaging device 22 is configured with a microscope, a camera, etc., and images the surface of the workpiece W at high magnification (e.g., 8.0x) or low magnification (e.g., 1.0x) by changing the lens of the microscope. Is possible. As the camera, an area sensor camera is used.

The imaging device 22 is fixed to the spindle 20 via a holding member 24, and is movable integrally with the spindle 20 in the Y direction and the Z direction. Furthermore, two stages may be provided to individually control the positions of the microscope of the imaging device 22 and the spindle 20. In this case, a drive shaft for the microscope is provided separately from the drive shaft for the spindle 20, and the spindle 20 and the microscope are moved individually along their respective drive shafts.

When determining the tip shape of the blade 18, the Z table moves the blade 18 in the -Z direction with respect to the blade determination workpiece W0 held by suction on the sub-table 13. Then, the tip (cutting edge) of the blade 18 is brought into contact with the blade determination workpiece W0 substantially perpendicularly to form a groove (kerf) of a predetermined depth that does not penetrate the blade determination workpiece W0 (chop cut or chop processing). Thereafter, the blade 18 is moved in the +Z direction by the Z table. During this time, the relative position of the sub-table 13 to the blade 18 remains unchanged. Note that the relative position of the sub-table 13 with respect to the blade 18 may be corrected depending on the temperature characteristics of both the blade 18 and the sub-table 13 so that the relative position of the sub-table 13 with respect to the blade 18 is always constant.

The imaging device 22 includes a light projection unit that irradiates light onto the object to be imaged, and irradiates the blade judgment workpiece W0 with light and receives reflected light from the blade judgment workpiece W0 to obtain a planar image of the kerf. Take an image. This plane image of the kerf is input to the control unit 56, and the control unit 56 determines the shape of the tip of the blade 18. Here, as the workpiece W0 for blade determination, a workpiece whose surface is mirror-finished (mirror workpiece) or a workpiece whose surface has a high reflectance such as a glass plate is used. Thereby, the outline of the kerf becomes clear due to the difference in reflectance between the surface of the blade determination workpiece W0 and the kerf, so that it becomes possible to accurately determine the tip shape of the blade 18. Note that the control unit 56 and the imaging device 22 are examples of the blade shape determination unit of the present invention.

During the dicing process, the work table 12 holds the workpiece W to be processed by suction. The workpiece W is attached to the frame F via a dicing tape T having an adhesive on its surface, and is held by suction on the worktable 12. Note that the frame F to which the dicing tape T is attached is held by frame holding means (not shown) provided on the work table 12.

FIG. 2 is a plan view showing a workpiece W to be processed. As shown in FIG. 2, processing lines (dividing lines) S are formed in a grid pattern on the surface of the workpiece W, and devices are placed in a plurality of regions (device forming regions) C partitioned by these processing lines S. is formed.

The control device 50 controls the operation of each part of the dicing device 10. The control device 50 is realized by, for example, a general-purpose computer such as a personal computer or a microcomputer.

The control device 50 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a hard disk, and the like. In the control device 50, various programs such as a control program stored in the ROM are expanded to the RAM, and the programs expanded to the RAM are executed by the CPU, so that each part shown in the control device 50 in FIG. A function is realized.

The control device 50 functions as a cutting mark detection section 52, a storage section 54, a map creation section 58, and a control section 56.

The control section 56 controls the operation of each section of the control device 50. Specifically, the control unit 56 controls the cutting feed of the work table 12 in the X direction via the X drive unit, and the rotation of the work table 12 in the θ direction via the θ drive unit. The control unit 56 also controls index feeding of the spindle 20 in the Y direction via the Y drive unit and incision feed of the spindle 20 in the Z direction via the Z drive unit. Further, the control unit 56 controls the rotational operation of the spindle 20 and the imaging operation of the imaging device 22.

The storage unit 54 stores various data necessary for the operation of the dicing apparatus 10. The various data stored in the storage unit 54 include data regarding the work W, data regarding alignment, and the thickness of the dicing tape T. For example, the data regarding the workpiece W includes the product number, material, external dimensions, thickness, chip size, etc. The various data stored in the storage unit 54 also include data on the calibration map and data on the determination result of the tip shape of the blade 18. Furthermore, the various data stored in the storage unit 54 also include a cutting mark formation rate Q and a correction table (see FIG. 9), which will be described later.

The cutting mark detection unit 52 receives image data captured by the imaging device 22 during the dicing process, and detects cutting mark information, which will be described later, through image processing or the like.

[Operation of dicing device 10]
Next, the operation of the dicing apparatus 10 configured as described above will be explained.

First, the work W to be processed, which is attached to the frame F via the dicing tape T, is transported by a transport means (not shown) and placed on the work table 12. The work W placed on the work table 12 is imaged by the imaging device 22, and an alignment operation for relative positioning of the work W and the blade 18 is started.

When the alignment operation is completed, the spindle 20 is started to rotate the blade 18, and cutting water and cooling water are supplied from various nozzles (not shown) provided in a wheel cover (not shown) that covers the blade 18. In this state, the work table 12 is fed for cutting in the X direction, and the spindle 20 is fed for cutting in the Z direction, so that the workpiece W is diced along the processing line S. Each time one line is processed, the spindle 20 is index-fed in the Y direction, and when processing in one direction is completed, the work table 12 is rotated 90 degrees and the workpiece W is diced into a grid pattern.

In this embodiment, before dicing the work W to be processed, a calibration map is created and the tip shape of the blade 18 is determined. During dicing of the workpiece W, a cutting mark detection operation and a blade height correction operation, which will be described later, are performed for each processing line S.

Note that in this embodiment, the cutting mark detection operation and the blade height correction operation, which will be described later, are performed for each processing line S, but the present invention is not limited to this. It may be performed for every 5 processing lines). Alternatively, the processing may be performed on a processing line S designated by the user (for example, processing lines S such as the first line, the fifth line, the seventh line, etc.).

(Creation of calibration map)
Next, creation of a calibration map will be explained.

In this embodiment, a calibration map is created by measuring in advance the shape (unevenness) of the surface of the work table 12 on which the workpiece W to be processed is placed. Then, the height of the blade 18 is controlled using this calibration map. This allows the cutting depth of the blade 18 into the dicing tape T to be constant.

When creating a calibration map, the displacement sensor 25 scans in the X and Y directions while measuring the shape (irregularities) of each position on the surface of the calibration workpiece held by suction on the work table 12. At this time, the displacement sensor 25 scans in the X and Y directions using the X table 16 and the Y table.

The map creation unit 58 determines the height position (Z coordinate) of the surface of the calibration work from the detection signal output from the displacement sensor 25. Then, the map creation unit 58 calculates the height position (Z coordinate) of each position on the surface of the work table 12 by subtracting the thickness of the calibration workpiece from the height position (Z coordinate) of the surface of the calibration workpiece. Then, a calibration map showing the shape of each position on the surface of the work table 12 is created.

FIG. 3 is a diagram showing an example of a calibration map. In the example shown in FIG. 3, the shape of each position on the surface of the work table 12 is expressed as the Z coordinate of each position on the surface of the work table 12 when the work table 12 is set on the XY plane (Z=0). .

In this embodiment, a calibration workpiece having approximately the same shape as the workpiece W to be machined or a calibration workpiece larger than the workpiece W to be machined is used, and while scanning the displacement sensor 25 in the XY direction, the calibration workpiece is Create a calibration map for the entire surface held by suction. Then, using this calibration map, the height of the blade 18 relative to the workpiece W to be machined is controlled (see FIG. 11). This makes it possible to control the height of the blade 18 according to the shape of the surface of the work table 12 on which the workpiece W to be processed is held by suction.

(Determination of blade tip shape)
Next, determination of the tip shape of the blade 18 will be explained.

As wear of the blade 18 progresses, the annular cutting edge portion of the blade 18 becomes thinner and the diameter of the blade 18 becomes smaller in order to cut the workpiece W to be processed. Then, the amount of cutting on the back surface (the surface to which the dicing tape T is attached) of the workpiece W to be processed decreases. For this reason, if the height control is performed in the same way as the blade 18 before wear, the cutting amount of the workpiece W will be insufficient due to the decrease in the amount of cutting on the backside of the workpiece W. cracks (chipping) are more likely to occur. Therefore, in this embodiment, before the dicing process, the shape of the tip of the blade 18, that is, the shape of the outer peripheral portion including the outer peripheral end of the cutting edge portion of the blade 18 is determined. Then, in addition to the calibration map, the height of the blade 18 during the dicing process is controlled based on the determination result of the tip shape of the blade 18. This makes it possible to prevent chipping caused by wear of the blade 18.

To determine the shape of the tip of the blade 18, a groove (kerf) is formed using the blade 18 on the surface of the blade determination workpiece W0 held by suction on the sub-table 13. Then, the control unit 56 captures an image of this kerf using the imaging device 22, and determines the shape of the tip of the blade 18 based on the plane shape of the captured kerf.

Specifically, when the wear of the blade 18 is not progressing, the variation in the width of the kerf in the longitudinal direction of the kerf is small, and the shape of both ends of the kerf becomes approximately rectangular (see kerf C1 in FIG. 4). ). On the other hand, as the wear of the blade 18 progresses, the thickness of the cutting edge portion of the blade 18 becomes thinner, so that the width of the kerf becomes narrower toward both ends of the kerf, and becomes triangular. As the wear of the blade 18 progresses, the width at both ends of the kerf becomes narrower and the angle at both ends of the kerf becomes smaller (see kerfs C2 and C3 in FIG. 4).

Further, the tip shape of the blade 18 may be determined by measuring the depth of the kerf using the displacement sensor 25 or the like. When the wear of the blade 18 is not progressing, the variation in the depth of the kerf in the width direction of the kerf is small. On the other hand, as the wear of the blade 18 progresses, the thickness of the cutting edge of the blade 18 becomes thinner or the diameter of the blade 18 decreases, so the variation in the depth of the kerf in the width direction of the kerf increases. Also, the depth of the kerf becomes shallower.

In this embodiment, the tip shape of the blade 18 is determined using the characteristics of the kerf formed on the blade determination workpiece W0. Note that, for determining the tip shape of the blade 18, it is possible to apply, for example, the blade diagnosis method described in Japanese Patent Application Laid-Open No. 2017-164843. Furthermore, the method for determining the tip shape of the blade 18 is not limited to using an image of the kerf. For example, it is also possible to determine the shape of the tip of the blade 18 by photographing the tip of the blade 18 including the outer peripheral edge of the cutting edge from a direction parallel to the blade 18 using a camera and analyzing this image. be. For example, images of the tip of the blade 18 may be accumulated, and the shape of the tip of the blade 18 may be determined from changes in the images of the tip of the blade 18 over time.

FIG. 4 is a plan view showing the planar shape of the calf. FIG. 5 is a table showing an example of the amount of correction of the height of the blade 18 for each determination result of the tip shape of the blade 18.

The kerf indicated by reference numeral C1 in FIG. 4 has a substantially rectangular planar shape at both ends, and the amount of wear of the blade 18 is minimized. In this case, as shown in FIG. 5, the cutting amount of the blade 18 into the dicing tape T is added by 5 μm.

On the other hand, the kerf shown by reference numeral C3 in FIG. 4 has a substantially triangular planar shape with acute angles at both ends, and the amount of wear of the blade 18 is maximum. In this case, as shown in FIG. 5, the cutting amount of the blade 18 into the dicing tape T is added by 15 μm.

Furthermore, although the kerf indicated by reference numeral C2 in FIG. 4 has a substantially triangular shape with acute angles at both ends, the angle at both ends is smaller than C3, and the amount of wear on the blade 18 is between the examples C1 and C3. be. In this case, as shown in FIG. 5, the cutting amount of the blade 18 into the dicing tape T is added by 7.5 μm.

In this embodiment, the greater the amount of wear of the blade 18, the lower the height of the blade 18 during dicing processing, and the greater the amount of cut into the dicing tape T. Thereby, occurrence of chipping due to wear of the blade 18 can be prevented.

Note that the creation of the calibration map and the determination of the tip shape of the blade 18 do not need to be performed every time dicing is performed, and may be performed, for example, every time dicing is performed a predetermined number of times. Furthermore, since wear of the blade 18 is thought to occur more easily than changes in the shape of the surface of the work table 12, the creation of the calibration map should be performed less frequently than the determination of the tip shape of the blade 18. Good too.

(Cutting mark detection operation)
Next, the cutting mark detection operation will be explained.

FIG. 6 is a schematic diagram showing how the workpiece W is subjected to dicing.

In this embodiment, as shown in FIG. 6, the blade 18 performs dicing while moving relative to the workpiece W from a cutting start position P1 on one side of the workpiece W to a cutting end position P4 on the other side. Processing is performed. At this time, cutting grooves 26 are formed in the workpiece W, and the surface area R of the dicing tape T to which the workpiece W is not attached (hereinafter referred to as "dicing tape area R") is cut by the blade 18. A mark 28 is formed.

For example, if the cutting marks 28 in the dicing tape region R are short and fragmented as a whole (see FIG. 6), or if there are no cutting marks 28 at all, the blade 18 may cause a shallow cut. It becomes. In this case, the blade 18 does not cut into the workpiece W sufficiently, which causes cutting defects.

On the other hand, if the cutting marks 28 in the dicing tape region R are long and connected as a whole, the blade 18 is making a deep cut. In this case, the blade 18 may become clogged and become less sharp.

As a result of repeated studies, the inventor of the present invention found that in order to stabilize processing quality, the height (position in the Z direction) of the blade 18 should be corrected based on the cutting mark formation rate Q in the dicing tape region R. I found something good. Here, the cutting mark formation rate Q is the ratio of the area (length in the cutting feed direction) in which the cutting marks 28 are formed in the dicing tape area R to the whole (total length in the cutting feed direction of the dicing tape area R). means.

The cutting mark detection operation in this embodiment is performed by imaging the dicing tape region R with the imaging device 22.

FIG. 7 is a schematic diagram showing how the imaging device 22 images the dicing tape region R. As shown in FIG. 7, the imaging device 22 images the dicing tape region R at a plurality of locations at high magnification while shifting the position relative to the dicing tape region R in the X direction, and divides the dicing tape region R into a plurality of divided images. Capture the entire image. Image data captured by the imaging device 22 is output to the control device 50. Note that the imaging device 22 may image a wide range of the dicing tape region R at once using low magnification.

Note that in this embodiment, an area sensor camera is used as the camera that constitutes the imaging device 22, but the invention is not limited to this, and for example, a line sensor camera may be used.

FIG. 8 is a schematic diagram showing how the line sensor camera 30 images the dicing tape region R. As shown in FIG. 8, the line sensor camera 30 has a plurality of light receiving elements (not shown) arranged in a row in the Y direction, and scans in the X direction to image the entire dicing tape area R. It has become.

The cutting mark detection unit 52 detects the length of the cutting mark 28 formed in the dicing tape region R (the length in the cutting feed direction) by performing image processing on the image data captured by the imaging device 22 using a known method. do. Furthermore, the cutting mark detection unit 52 calculates the cutting mark formation rate Q in the dicing tape region R based on the length of the detected cutting marks 28.

Here, a method for calculating the cutting mark formation rate Q in the dicing tape region R will be explained.

In FIG. 6, when the blade 18 moves relative to the workpiece W from the cutting start position P1 to the cutting end position P4, the position where the blade 18 starts cutting into the workpiece W is defined as a workpiece entry position P2, and the blade 18 moves toward the workpiece W. The position where the cut into the W ends is defined as the workpiece exit position P3.

At this time, the cutting marks 28 are formed in the dicing tape region R1 between the cutting start position P1 and the work entry position P2, and in the dicing tape region R2 between the work exit position P3 and the cutting end position P4.

Further, the total lengths of the dicing tape regions R1 and R2 in the cutting feed direction (X direction) are respectively L1 and L2, and the total length of the cutting marks 28 formed in each of the dicing tape regions R1 and R2 is l1, Let it be l2. For example, as shown in FIG. 6, when a plurality of cutting marks 28 are formed in the dicing tape region R1, the total length of each cutting mark 28 is set to l1. The same applies to the dicing tape region R2.

The cutting mark detection unit 52 calculates the cutting mark formation rate Q using the following equation (1). This cutting mark formation rate Q is stored in the storage unit 54 in association with processing line information (processing line number, etc.) when the cutting marks 28 were formed. Note that the unit of the cutting mark formation rate Q is %.

Q={(l1+l2)/(L1+L2)}×100...(1)
(Blade height correction operation)
Next, the blade height correction operation will be explained.

In the blade height correction operation, the control unit 56 acquires the cutting mark formation rate Q of the reference line from the storage unit 54. The reference line is a processing line S on which dicing was performed immediately before the current processing line S, and the cutting mark formation rate Q has already been calculated by the cutting mark detection operation described above.

The control unit 56 further determines the blade height correction amount G corresponding to the cutting mark formation rate Q of the reference line according to the correction table (see FIG. 9) stored in the storage unit 54. Then, the control unit 56 controls the height (Z-direction position) of the blade 18 based on the determined blade height correction amount G.

(correction table)
FIG. 9 is a diagram showing an example of a correction table. As shown in FIG. 9, the correction table shows the correspondence between the cutting mark formation rate Q and the blade height correction amount G. This correction table also includes a target cutting mark formation rate (target formation rate) and its tolerance range (target formation rate tolerance range). Note that each numerical value in the correction table can be appropriately set by the user via an operation unit (not shown) connected to the control device 50. Further, when the blade height correction amount G is a positive value, it indicates a correction in the direction of increasing the depth of cut into the workpiece W from the set value, and when it is a negative value, it indicates a correction from the set value. This shows the correction in the direction in which the depth of cut into the workpiece W becomes shallower.

(Specific operation example)
FIG. 10 is a diagram showing a specific example of operation in this embodiment. FIG. 11 is a diagram showing the locus of the tip (-Z side end) of the blade 18. Here, in order to simplify the explanation, a case will be described in which dicing is performed on four processing lines S1 to S4 along the cutting feed direction (X direction) in the order of line numbers.

As shown in FIG. 10, first, dicing is performed on the first processing line S1. In this case, since there is no reference line, the control unit 56 sets the blade height correction amount G to 0, and leaves the height of the blade 18 at the set value without correcting it. Then, dicing is started from the notch side of the workpiece W to be processed.

When the blade 18 reaches the workpiece W to be processed, the control unit 56 performs the dicing process while correcting the height of the blade 18 based on the calibration map and the determination result of the tip shape of the blade 18. Reference numeral 18T in FIG. 11 indicates the locus of the tip of the blade 18. Specifically, as shown in FIG. 11, the control unit 56 detects that the cutting edge of the blade 18 has come into contact with the upper end of the workpiece W to be machined, based on changes in the torque applied to the spindle 20, etc. . Note that the control unit 56 causes the cutting edge of the blade 18 to contact the upper end of the workpiece W to be processed based on the positional relationship between the workpiece W to be processed and the blade 18 detected by the imaging device 22 or a position sensor, etc. It may also be possible to detect what has happened. Then, the blade 18 is gradually pushed down to the -Z side while scanning in the X direction. Then, the height position is obtained by adding the correction amount for the height of the blade 18 based on the calibration map and the correction amount based on the determination result of the tip shape of the blade 18 (see FIG. 5) to the blade height correction amount G. The dicing process is performed while controlling the position of the blade 18.

Next, when the control unit 56 detects that the blade 18 has separated from (cut through) the workpiece W to be processed, it gradually raises the blade 18 to the +Z side and adjusts the blade height correction amount G (first processing line In S1, the process shifts to height control using only G=0). Here, cut-through can also be detected based on a change in the torque applied to the spindle 20 or the positional relationship between the workpiece W to be processed and the blade 18.

The cutting mark detection unit 52 calculates the cutting mark formation rate (23% in this example) of the first processing line S1 based on the image data captured by the imaging device 22 on the cut-out side of the workpiece W to be processed. The information is stored in the storage unit 54.

Next, dicing processing is performed on the second processing line S2. In this case, the control unit 56 acquires the cutting mark formation rate Q (23%) of the first machining line S1, which is the reference line, from the storage unit 54. Then, the control unit 56 determines the blade height correction amount G to be +0.006 mm, controls the height of the blade 18 according to the blade height correction amount G, and performs dicing from the cutting side of the workpiece W to be processed. Start.

When the blade 18 reaches the workpiece W to be processed, the blade 18 is gradually pushed down toward the −Z side while scanning in the X direction. Then, the height position is obtained by adding the correction amount for the height of the blade 18 based on the calibration map and the correction amount based on the determination result of the tip shape of the blade 18 (see FIG. 5) to the blade height correction amount G. The dicing process is performed while controlling the position of the blade 18. When the control unit 56 detects that the blade 18 has separated from (cut through) the workpiece W to be machined, it gradually raises the blade 18 toward the +Z side and shifts to height control using only the blade height correction amount G. .

The cutting mark detection unit 52 determines the cutting mark formation rate (78% in this example) of the second processing line S2 based on the image data captured by the imaging device 22 on the cut-out side (+X side) of the workpiece W to be processed. It is calculated and stored in the storage unit 54.

Next, dicing processing is performed on the third processing line S3. In this case, the control unit 56 acquires the cutting mark formation rate (78%) of the second machining line S2, which is the reference line, from the storage unit 54. At this time, since the cutting mark formation rate (78%) exceeds the allowable range (±5%) of the target rate (70%), the control unit 56 determines the blade height correction amount G to be -0.001 mm. Then, the height of the blade 18 is controlled according to the blade height correction amount G, and the dicing process is started from the incision side of the workpiece W to be processed.

When the blade 18 reaches the workpiece W to be machined, similarly to the above case, the amount of correction for the height of the blade 18 based on the calibration map and the amount of correction based on the determination result of the tip shape of the blade 18 (see FIG. 5) ) is added to the blade height correction amount G, and the dicing process is performed while controlling the position of the blade 18. When the control unit 56 detects that the blade 18 has separated from (cut through) the workpiece W to be machined, it shifts to height control using only the blade height correction amount G.

The cutting mark detection unit 52 determines the cutting mark formation rate (73% in this example) of the third processing line S3 based on the image data captured by the imaging device 22 on the cut-out side (+X side) of the workpiece W to be processed. It is calculated and stored in the storage unit 54.

Next, dicing processing is performed on the fourth processing line S4. In this case, the control unit 56 acquires the cutting mark formation rate (73%) of the third machining line S3, which is the reference line, from the storage unit 54. At this time, since the cutting mark formation rate (73%) is within the tolerance range (±5%) of the target rate (70%), the control unit 56 determines the blade height correction amount G to be 0 mm, and The height of the blade 18 is controlled according to the height correction amount G. The subsequent control is the same as that for the first to third processing lines S1 to S3, so the explanation will be omitted.

In addition, in this embodiment, the blade height correction amount of the blade 18 is controlled based on the calibration map, the tip shape of the blade 18, and the cutting mark formation rate, but the present invention is not limited to this. isn't it. For example, the blade 18 may be offset by a predetermined amount toward the −Z side in order to reliably perform dicing on the workpiece W regardless of the state of wear of the blade 18.

(flowchart)
FIG. 12 is a flowchart showing the flow of the blade height correction operation. As shown in FIG. 12, in this embodiment, prior to the dicing process (step S30), a calibration map is created (step S10) and the tip shape of the blade 18 is determined (step S20).

(Calibration map creation process)
FIG. 13 is a flowchart showing the calibration map creation process.

First, as shown in FIG. 13, a calibration workpiece is suctioned and held (installed) on the surface of the work table 12 via a dicing tape T (step S100), and the shape of the surface of the calibration workpiece is measured by the displacement sensor 25. .

Next, the map creation unit 58 calculates the shape of the surface of the work table 12 based on the measurement result of the shape of the surface of the calibration work (step S102). Then, the map creation unit 58 creates calibration map data indicating the shape of the surface of the work table 12, and stores it in the storage unit 54 (step S104).

(Blade shape determination process)
FIG. 14 is a flowchart showing the blade shape determination process.

First, the blade determination workpiece W0 is suctioned and held on the sub-table 13. Then, the blade 18 is brought into contact with the blade determination workpiece W0 to form a kerf with a predetermined depth on the surface of the blade determination workpiece W0 (step S200).

Next, a planar image of the calf is captured by the imaging device 22 (step S202). The cutting mark detection unit 52 extracts the outline of the kerf from the planar image of the kerf, and measures the dimensions of the kerf (step S204). Then, the control unit 56 calculates the shape of the tip of the blade 18 based on the dimensions of this kerf (step S206).

(dicing process)
FIG. 15 is a flowchart showing the dicing process.

First, the work W to be processed is held by suction on the surface of the work table 12. Then, cutting is started from the first processing line S(i) (i=1) (step S300).

When cutting on the machining line S(i), the blade height correction amount G is determined based on the cutting mark formation rate on the cutting side of the work W, and while controlling the height of the blade 18, the machining line S(i) ) is cut (step S302).

When it is detected that the blade 18 has reached the workpiece W to be machined (Yes in step S304), the control unit 56 calculates the calibration map and the blade height correction amount G determined based on the cutting mark formation rate. The machining line S(i) is cut while controlling the height of the blade 18 based on the tip shape of the blade 18 (step S306: control step). When it is detected that the blade has cut through the workpiece W (Yes in step S308), the control unit 56 shifts to height control of the blade 18 based on the cutting mark formation rate (step S310).

Next, the cutting mark detection unit 52 detects cutting mark information on the cut-out side of the processing line S(i) (Yes in step S312, step S314). Then, the cutting mark detection unit 52 calculates the cutting mark formation rate Q in the dicing tape region R based on the detected cutting mark information. Then, the cutting mark detection unit 52 stores the calculated cutting mark formation rate Q in the storage unit 54 in association with information regarding the processing line S (line information).

Next, with i=i+1, the process moves to the next processing line S(i) (step S316) and performs cutting (steps S302 to S312). Then, steps S302 to S312 are repeated, and when cutting of all processing lines S(i) (see FIG. 2) in the XY directions is completed (Yes in step S312), the dicing process is completed.

[Actions and effects of this embodiment]
Next, the effects of this embodiment will be explained.

According to this embodiment, the height of the blade 18 is controlled based on the shape of the surface of the work table 12 on which the workpiece W to be processed is held by suction, and the height of the blade 18 is controlled in consideration of the progress of wear of the blade 18. The cutting depth of the blade 18 is adjusted. Furthermore, according to the present embodiment, the depth of the cut into the dicing tape T is made constant based on the cutting mark information in the dicing tape region R (the surface region of the dicing tape T to which the workpiece W is not attached). The height of the blade 18 is controlled. As a result, the depth at which the blade 18 cuts into the dicing tape T can be made relatively shallow and constant without being affected by the waviness of the work table 12 or variations in the thickness of the dicing tape T. Quality can be stabilized. Furthermore, since the cutting depth of the blade 18 is adjusted in consideration of the progress of wear of the blade 18, it is possible to prevent chipping on the back side of the workpiece W.

Further, according to the present embodiment, the cutting mark detection unit 52 detects cutting mark information in the dicing tape region R based on image data captured by the imaging device 22. The imaging device 22 is composed of an alignment camera and is originally included in the dicing device 10, so that problems such as complication of the device configuration and increase in cost do not occur.

Note that in this embodiment, the cutting mark information is configured to be detected based on the image data captured by the imaging device 22, but the present invention is not limited to this. Cutting mark information may be detected using the following method. Alternatively, the cutting mark information may be detected visually.

Further, when the number of processing lines is large (for example, 2067 lines), the amount of blade wear until the dicing processing of all processing lines S is completed cannot be ignored. Therefore, conventionally, it was necessary to set the cutter many times during the dicing process, measure the current amount of blade wear, and adjust the height of the blade 18. On the other hand, in this embodiment, during the dicing process of the work W, the cutting mark detection operation is performed for each process line S. Therefore, the current amount of blade wear can be grasped in real time, which eliminates the need to frequently measure the amount of blade wear as in the past, which has the advantage of reducing the time it takes to complete the dicing process. be.

Furthermore, in this embodiment, when performing dicing on the current processing line S, the blade height correction amount G is determined using the cutting mark formation rate Q using the immediately previous processing line S as a reference line. However, the present invention is not limited to this, and a processing line S temporally or spatially adjacent to or close to the current processing line S may be used as the reference line. Note that the adjacent machining line S means a machining line that is temporally or spatially adjacent to the current machining line S. Further, the proximate processing line S means a processing line S that is within a range of several lines (for example, 1 to 5 lines) temporally or spatially from the current processing line. Further, the reference line is not limited to one machining line S, but may be a plurality of machining lines S. In this case, for example, the blade height correction amount G may be determined based on the average value of the cutting mark formation rates Q corresponding to the plurality of processing lines S, respectively.

Furthermore, in this embodiment, there is a possibility that the cutting quality of the processing line S (first 1 to 3 lines) in which dicing is performed may deteriorate until the height of the blade 18 becomes stable. This problem can be solved by performing blank cutting on the dicing tape T several times before actually starting the dicing process to adjust the height of the blade 18 in advance before performing the dicing process.

Furthermore, in the present embodiment, in the cutting mark detection operation, the lengths of the cutting marks 28 in both the dicing tape region R1, which is the incision side, and the dicing tape region R2, which is the cutout side, are measured, but the cutting conditions Depending on the situation, the following actions may be considered.

(For workpieces with high cutting load)
Since the blade 18 wears more during the dicing process, only the length of the cutting marks 28 existing in the dicing tape region R2 on the cutting-through side is measured. This is because the blade 18 is severely worn during the dicing process, so even if the length of the cutting mark 28 in the dicing tape region R1 on the cutting side is measured, it cannot be used as a reference for correcting the height of the blade 18.

(If you want to improve overall throughput)
Only the cut marks 28 in the dicing tape region R1 on the incision side or the dicing tape region R2 on the cut-out side are measured, and the time required for the cut mark detection operation is shortened compared to the case where both sides are measured. In this case, since there is no need to leave the cutting marks 28 on the dicing tape T on the side where the cutting marks 28 are not measured, the work W can be cut at the closest possible position, and the cutting time can be further shortened.

(When considering the rigidity of dicing tape T)
The rigidity of the dicing tape T may change depending on the temperature. Specifically, when the temperature of the cutting environment is high, the rigidity of the dicing tape T becomes low. If the rigidity of the dicing tape T becomes low, when cutting the workpiece W using the blade 18, the workpiece W may be pushed toward the −Z side by the blade 18, and cutting may not be performed sufficiently. Therefore, in addition to the above conditions, the amount by which the blade 18 is pushed down may be adjusted in consideration of the temperature dependence of the rigidity of the dicing tape T.

Specifically, the temperature dependence of the rigidity of the dicing tape T (for example, the relationship between the temperature and the amount by which the workpiece W is pushed) is experimentally determined in advance, and the workpiece W is adjusted depending on the temperature of the cutting environment. The amount by which the blade 18 is pushed may be estimated and the amount by which the blade 18 is pushed down may be added. For example, when the temperature of the cutting environment is high, the rigidity of the dicing tape T decreases, so the higher the temperature of the cutting environment is, the larger the additional value of the amount of depression of the blade 18 is. On the other hand, the lower the temperature of the cutting environment, the smaller the additional value of the amount of depression of the blade 18.

[Other embodiments]
FIG. 16 is a schematic diagram showing the configuration of a dicing apparatus 10A according to another embodiment. In FIG. 16, components common to those in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted.

As shown in FIG. 16, a dicing apparatus 10A according to another embodiment includes a distance measuring device 32 in addition to the configuration of the dicing apparatus 10 according to this embodiment.

The distance measuring device 32 is arranged at a position facing the work table 12. The distance measuring device 32 measures the distance to the surface of the dicing tape region R, which is the object to be measured, and includes, for example, a laser displacement meter, an interference microscope, or the like. The measurement results of the distance measuring device 32 are outputted to the cutting mark detection section 52 as distance data.

Further, the distance measuring device 32 is fixed to the side surface of the imaging device 22, and is movable in the Y direction and the Z direction together with the spindle 20 and the imaging device 22.

With this configuration, the distance measuring device 32 measures the distance to the dicing tape region R while shifting the position relative to the dicing tape region R in the X direction as a cutting mark detection operation performed while the workpiece W is being diced. Distance data, which is the measurement result of the distance measuring device 32, is output to the cutting mark detection section 52.

The cutting mark detection unit 52 generates a height graph showing changes in height (unevenness) in the dicing tape region R based on the distance data acquired from the distance measuring device 32.

FIG. 17 is a diagram showing an example of a height graph generated by the cutting mark detection unit 52. As shown in FIG. 17, the cutting mark detection unit 52 identifies a region lower than a predetermined threshold height (height indicated by a broken line in FIG. 17) in the generated height graph as a cutting mark forming area K (cutting mark 28). Then, the cutting mark detection unit 52 calculates the cutting mark formation rate Q based on the detected cutting mark forming area K. The subsequent processing is similar to this embodiment.

According to another embodiment, cutting mark information in the dicing tape region R (the surface region of the dicing tape T to which the workpiece W is not attached) can be detected based on the measurement results of the distance measuring device 32. Similar to the present embodiment described above, it is possible to stabilize processing quality.

Although one example of the present invention has been described in detail, the present invention is not limited thereto, and it goes without saying that various improvements and modifications may be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10...Dicing device, 12...Work table, 13...Sub table, 14...θ table, 16...X table, 18...Blade, 20...Spindle, 22...Imaging device, 24...Holding member, 26...Cutting groove, 28... Cutting mark, 30... Line sensor camera, 32... Distance measuring device, 50... Control device, 52... Cutting mark detection section, 54... Storage section, 56... Control section, 58... Map creation section, 90... Blade, 92... Cutting Groove, W...Work, W0...Blade judgment work, T...Dicing tape, Q...Cutting mark formation rate, G...Blade height correction amount

Claims (8)

A dicing device that performs dicing by relatively moving a blade rotated by a spindle and the work table while holding a work to be processed on the work table via a dicing tape,
a map creation unit that creates a calibration map showing the shape of the entire surface of the work table from the measurement results of the shape of the entire surface of the calibration work held on the work table;
A planar image of the groove with a clear outline is obtained by imaging a groove formed on the surface of the blade determination workpiece, which has a higher reflectance than the surface of the workpiece to be machined, using the blade, and from the planar image, a blade shape determination unit that determines the tip shape of the blade;
Based on the calibration map, the tip shape of the blade , and a table showing the relationship between the tip shape of the blade and the correction amount of the blade height , depending on the shape of the surface of the work table and the wear of the blade, a control unit that controls the height of the blade when processing the workpiece so that the depth of cut into the dicing tape is constant;
A dicing device equipped with. The control unit determines the state of wear of the blade from the shape of the tip of the blade, and lowers the height of the blade as the wear progresses.
The dicing apparatus according to claim 1. The dicing apparatus according to claim 2, wherein the control unit determines the state of wear of the blade based on a planar shape of both ends of the groove. The dicing apparatus according to claim 3, wherein the control unit determines that the wear is progressing when the planar shape is triangular, and reduces the height of the blade. Further comprising a cutting mark detection unit that detects cutting mark information of cutting marks formed in a second area of the dicing tape other than the first area of the dicing tape to which the workpiece on the processing line is attached,
The cutting mark detection unit calculates a cutting mark formation rate corresponding to the sum of the length of the cutting marks formed in the second region with respect to the length of the processing line of the dicing tape, based on the cutting mark information. death,
The control unit controls the height of the blade based on the cutting mark formation rate so that the cutting mark formation rate is within a certain range.
A dicing apparatus according to any one of claims 1 to 4. A dicing method in which a workpiece to be processed is held on a worktable via a dicing tape, and dicing is performed by relatively moving a blade rotated by a spindle and the worktable, the method comprising:
a calibration map creation step of creating a calibration map showing the shape of the entire surface of the work table from the measurement results of the shape of the entire surface of the calibration work held on the work table;
A planar image of the groove with a clear outline is obtained by imaging a groove formed on the surface of the blade determination workpiece, which has a higher reflectance than the surface of the workpiece to be machined, using the blade, and from the planar image, a blade shape determination step of calculating the tip shape of the blade;
Based on the calibration map, the tip shape of the blade , and a table showing the relationship between the tip shape of the blade and the correction amount of the blade height , depending on the shape of the surface of the work table and the wear of the blade, a control step of controlling the height of the blade when processing the workpiece to be processed so that the depth of cut into the dicing tape is constant;
A dicing method comprising: 7. The dicing method according to claim 6, wherein in the control step, the state of wear of the blade is determined from the shape of the tip of the blade, and the more the wear progresses, the lower the height of the blade is. The dicing method according to claim 7, wherein in the control step, the state of wear of the blade is determined based on the planar shape of both ends of the groove.

Images