Dicing groove inspection method and dicing device

Abstract

To provide an inspection method of a dicing groove capable of easily performing a kerf checking in the case of performing a step cut with high accuracy, and provide a dicing device.SOLUTION: An inspection method of a dicing groove, contains: a step of forming a first dicing groove to a front surface of a work-piece by using a first blade (16-1); a step of forming a second dicing groove in that is deeper than the first dicing groove in the first dicing groove along the first dicing groove ny using, a second blade (16-2) thinner than the first blade and being other than the first blade; and a step of detecting an edge part of the second dicing groove by observing a work edge part by using an observation part that is inclined to a Z shaft from a straight line extended to an end part of the second dicing groove from a center of a cross section along a ZX surface of the work edge part in the case where a shaft orthogonal to the front surface of the work-piece is the Z shaft, and a shaft along a dicing direction is a X shaft.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to a dicing groove inspection method and a dicing device, and more particularly to a dicing groove inspection method for dividing a workpiece such as a wafer on which semiconductor devices or electronic components are formed into individual chips. [Background technology]

[0002] A dicing machine that divides workpieces such as semiconductor devices or wafers on which electronic components are formed into individual chips is equipped with a blade that is rotated at high speed by a spindle, a worktable that suction-holds the workpiece, and an XYZθ drive unit that changes the relative position between the worktable and the blade. This dicing machine performs dicing (cutting) by cutting into the workpiece with the blade while the blade and the workpiece are moved relative to each other by the respective drive units.

[0003] When dicing, the processed area is measured (kerf check) to check the quality of the cutting line and the positional accuracy of the dicing groove (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-085397 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-099026 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a workpiece consisting of a silicon layer and a device layer (metal film) formed on the surface of the silicon layer is divided in a single cutting process (single cut), the processing quality on the back side of the workpiece may deteriorate due to the influence of the device layer, etc.

[0006] For this reason, in dicing, to improve processing quality, a step cut is performed in which cutting is performed in stages using a surface blade (hereinafter referred to as the first blade) to remove metal from the surface of the workpiece and a silicon blade (hereinafter referred to as the second blade) to cut the silicon layer inside the workpiece. In step cuts, the first blade and the second blade cut into the same position on the workpiece surface, so the dicing grooves formed by the second blade, which will be described later, cannot be observed with a microscope from above the workpiece surface.

[0007] FIG. 16 is a cross-sectional view showing an example of a step cut. As shown in FIG. 16, the workpiece consists of a device layer W1 formed on the front surface side and a silicon layer W2, with dicing tape T attached to the back surface side of the silicon layer W2. Symbol g1 in the figure indicates a groove formed when the device layer W1 is removed with the first blade, and symbol g2 indicates a groove for cutting the silicon layer W2 with the second blade. As shown in FIG. 16, the edge e2 of the groove g2 is inside the groove g1 and therefore cannot be observed with a microscope. Furthermore, because the groove g1 is inclined, it is difficult to accurately measure its position with a measuring instrument.

[0008] For this reason, when performing a step cut, it is considered to use the second blade to perform a small check cutting process on the surface of the workpiece beforehand to check the blade position and condition. However, in this case, the second blade may be damaged by the check cutting process, which may deteriorate the processing quality.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide a dicing groove inspection method and dicing apparatus that enable accurate and easy kerf checking when performing step cuts. [Means for solving the problem]

[0010] In order to solve the above problem, a dicing groove inspection method according to a first aspect of the present invention includes the steps of: using a first blade to form a first dicing groove on the surface of a workpiece; using a second blade different from the first blade to form a second dicing groove along the first dicing groove, the second dicing groove being deeper than the first dicing groove; and using an observation unit to observe a concave region that overlaps at least a portion of the second dicing groove and is deeper than the first dicing groove, and detecting an edge portion between the second dicing groove and the concave region.

[0011] A dicing groove inspection method according to a second aspect of the present invention is the same as the first aspect, and further comprises a cut portion forming step of forming a cut portion as a recessed area.

[0012] A dicing groove inspection method according to a third aspect of the present invention includes, in the cut portion forming step of the second aspect, forming a check groove that intersects with the first and second dicing grooves and is deeper than the first dicing groove.

[0013] A dicing groove inspection method according to a fourth aspect of the present invention is the same as the second aspect in that in the cut portion forming step, the cut portion is formed by trimming the peripheral edge of the workpiece deeper than the first dicing groove.

[0014] A dicing device according to a fifth aspect of the present invention comprises a first cutting unit having a first blade that forms a first dicing groove on the surface of a workpiece, a second cutting unit having a second blade that forms a second dicing groove along the first dicing groove and that is deeper than the first dicing groove, and an observation unit that observes a concave area that overlaps with at least a portion of the second dicing groove and is deeper than the first dicing groove, and detects the edge portion between the second dicing groove and the concave area. [Effects of the Invention]

[0015] According to the present invention, when a step cut is performed, the second dicing groove can be detected accurately and easily. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing a dicing device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing a control system of a dicing apparatus according to one embodiment of the present invention. [Figure 3] FIG. 3 is a perspective view showing a first embodiment of a dicing groove inspection method. [Figure 4] FIG. 4 is a perspective view showing a part of a workpiece in which a check groove and first and second dicing grooves are formed. [Figure 5] FIG. 5 is a plan view showing a part of a workpiece in which a check groove and first and second dicing grooves are formed. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a perspective view showing a part of a workpiece in which the depths of the check groove and the first dicing groove are approximately the same. [Figure 8] FIG. 8 is a plan view showing a part of a workpiece when the depth of the check groove and the depth of the first dicing groove are approximately the same. [Figure 9] FIG. 9 is a perspective view showing a part of a workpiece in which the first dicing groove is deeper than the check groove. [Figure 10] FIG. 10 is a plan view showing a part of a workpiece in which the first dicing groove is deeper than the check groove. [Figure 11] FIG. 11 is a perspective view showing a second embodiment of the dicing groove inspection method. [Figure 12] FIG. 12 is a plan view showing a second embodiment of the dicing groove inspection method. [Figure 13] FIG. 13 is a perspective view showing a third embodiment of the dicing groove inspection method. [Figure 14] FIG. 14 is a side view of the workpiece. [Figure 15] FIG. 15 is a view seen from the direction of arrow XV in FIG. [Figure 16]FIG. 16 is a cross-sectional view showing an example of a step cut. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a dicing groove inspection method and a dicing apparatus according to the present invention will be described with reference to the accompanying drawings.

[0018] [Dicing equipment] First, the dicing device will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing a dicing device according to an embodiment of the present invention. The following description will be given using a three-dimensional orthogonal coordinate system.

[0019] 1, the dicing device 10 according to this embodiment includes cutting units 12 (first cutting unit 12-1 and second cutting unit 12-2) that perform dicing processing on a workpiece (wafer) W, and a work table (cutting table; hereinafter referred to as table) CT. In the following description, components common to the two cutting units 12-1 and 12-2 will be described with their subnumbers omitted.

[0020] The table CT has a holding surface parallel to the XY plane, and the workpiece W is held by suction on this holding surface using a vacuum source (vacuum generator, e.g., an ejector, pump, etc., not shown). The workpiece W is attached to a frame (not shown) via dicing tape (not shown) having an adhesive layer formed on its surface, and is held by suction on the table CT. The frame to which the dicing tape is attached is held by frame holding means (not shown) disposed on the table CT. Note that a transport mode that does not use a frame is also possible.

[0021] Table CT is attached to a θ table (not shown), which can be rotated in the θ direction (around a rotation axis centered on the Z axis) by a rotary drive unit including a motor, etc. The θ table is placed on an X table (not shown), which can be moved in the X direction by an X drive unit including a motor, a ball screw, etc.

[0022] The first cutting unit 12-1 and the second cutting unit 12-2 are attached to a Z1 table and a Z2 table, respectively, not shown. The Z1 table and the Z2 table are movable in the Z1 and Z2 directions by a Z drive unit including a motor, a ball screw, etc. The Z1 table and the Z2 table are attached to a Y1 table and a Y2 table, respectively. The Y1 table and the Y2 table are movable in the Y1 and Y2 directions by a Y drive unit including a motor, a ball screw, etc.

[0023] In this embodiment, the X, Y, and Z drive units include motors and ball screws, but the present invention is not limited to this. For example, mechanisms for reciprocating linear motion, such as rack-and-pinion mechanisms, can be used as the X, Y, and Z drive units.

[0024] 1, the first cutting unit 12-1 includes a first spindle 14-1 and a first blade 16-1, and the second cutting unit 12-2 includes a second spindle 14-2 and a second blade 16-2.

[0025] The first blade 16-1 and the second blade 16-2 are, for example, disk-shaped cutting blades. The first blade 16-1 is a blade for removing a device layer on the surface of the workpiece W, and the second blade 16-2 is a blade for cutting (dividing) the silicon layer of the workpiece W after removing the device layer. In the example shown in FIG. 1 , the first blade 16-1 is thicker than the second blade 16-2. The first blade 16-1 and the second blade 16-2 can be, for example, an electroplated blade in which diamond abrasive grains or CBN (Cubic Boron Nitride) abrasive grains are electrodeposited with nickel, or a resin blade in which diamond abrasive grains or CBN (Cubic Boron Nitride) abrasive grains are bonded with resin. The first blade 16-1 and the second blade 16-2 can be replaced depending on the type and size of the workpiece W to be processed, the processing content, etc.

[0026] The first blade 16-1 and the second blade 16-2 are attached to the tips of the first spindle 14-1 and the second spindle 14-2, respectively. The first spindle 14-1 and the second spindle 14-2 include high-frequency motors for rotating the first blade 16-1 and the second blade 16-2 at high speed, respectively.

[0027] With this configuration, the first blade 16-1 and the second blade 16-2 are indexed in the Y1 and Y2 directions and cut in the Z1 and Z2 directions, respectively. Also, the table CT is rotated in the θ direction and cut in the X direction.

[0028] (Dicing equipment control system) FIG. 2 is a block diagram showing a control system of a dicing apparatus according to one embodiment of the present invention.

[0029] 2, the control system of the dicing apparatus 10 according to this embodiment includes a control unit 100, an input unit 102, and a display unit 104. The control system of the dicing apparatus 1 can be realized by a general-purpose computer such as a personal computer or a microcomputer.

[0030] The control unit 100 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a storage device (for example, a hard disk, etc.), etc. In the control unit 100, various programs such as a control program stored in the ROM are loaded into the RAM, and the programs loaded into the RAM are executed by the CPU, thereby realizing the functions of each part of the dicing device 10.

[0031] The input unit 102 includes operation members (for example, a keyboard, a pointing device, etc.) for receiving operation inputs from the user.

[0032] Display unit 104 is a device that displays a GUI (Graphical User Interface) and the like for operating dicing device 10, and includes, for example, a liquid crystal display.

[0033] The observation unit MS includes a microscope, and captures (observes) an image of the surface of the workpiece W held by suction on the table CT. The surface image of the workpiece W captured by the observation unit MS is transmitted to the control unit 100. Note that, as the microscope in this embodiment, for example, an alignment microscope used for alignment or a shape detection microscope used for shape detection can be applied.

[0034] The MS driving unit 52 includes a power source (e.g., a motor) for moving the observation unit MS along the X and Y axes. A mechanism capable of reciprocating linear motion, such as a ball screw or a rack-and-pinion mechanism, can be used as a mechanism for moving the observation unit MS. While the present embodiment provides an MS driving unit 52 for the observation unit MS, the MS driving unit 52 can also be omitted. For example, if the observation unit MS can be moved together with the first cutting unit 12-1 or the second cutting unit 12-2 or other movable units, the MS driving unit 52 can be omitted.

[0035] The table drive unit 54 includes an X drive unit and a rotation drive unit for moving the table CT.

[0036] In this embodiment, the first cutting unit 12-1 and the second cutting unit 12-2 are moved in the Y and Z directions, the observation unit MS is moved along the X and Y axes, and the table CT is moved in the Xθ direction, but the present invention is not limited to this. For example, the table CT may be movable in the Y and Z directions.

[0037] [First embodiment] Next, a first embodiment of a dicing groove inspection method will be described.

[0038] As shown in FIG. 3, in this embodiment, first, a groove G1 (hereinafter referred to as a check groove) is formed in a portion of the surface of the workpiece W where a kerf check is to be performed, using a first blade 16-1, in a direction (Y direction) perpendicular to the dicing direction (X direction in FIG. 3) (cutting portion forming step). Here, the check groove G1 functions as the cutting portion of the present invention. The depth of the check groove G1 is set slightly deeper than the groove G2 formed using the first blade 16-1. Here, the first cutting portion 12-1 corresponds to the cutting portion forming portion of the present invention. The relationship between the cutting depth of the check groove G1 and the first dicing groove G2 will be described later.

[0039] In this embodiment, the check groove G1 is formed using the first blade 16-1, but the check groove G1 may be formed using the second blade 16-2 or other means (see the second embodiment).

[0040] Next, a step cut is performed along the dicing direction (X direction). That is, a first blade 16-1 is used to cut deeper than the device layer on the surface of the workpiece W to form a groove G2 (hereinafter referred to as a first dicing groove) along the X direction. Then, a second blade 16-2 is used to form a groove G3 (hereinafter referred to as a second dicing groove) along the X direction.

[0041] Figures 4 and 5 are a perspective view and a plan view, respectively, showing a part of a workpiece in which a check groove and first and second dicing grooves are formed. Figure 6 is a cross-sectional view taken along the line VI-VI in Figure 5. Note that the symbol T in Figure 6 represents a dicing tape.

[0042] 5 can be approximated to a plane, the edge E1 formed by the intersection of the second dicing groove G3 and the bottom B1 can be detected by the observation unit MS. Therefore, based on the detection result of the position of the edge E1, it is possible to evaluate the error in the formation position of the second dicing groove G3 and the state of the second blade 16-2.

[0043] The observation unit MS can also detect the edge E2 between the first dicing groove G2 and the surface Wa of the workpiece. Therefore, based on the detection result of the position of the edge E2, it becomes possible to evaluate the error in the formation position of the first dicing groove G2 and the state of the first blade 16-1.

[0044] The control unit 100 corrects the positions of the first blade 16-1 and the second blade 16-2 based on the detection results of the edge portions E1 and E2.

[0045] In the example shown in Figure 4, the check groove G1 has a deeper cut depth than the first dicing groove G2, so the edge portion E1 formed by the intersection of the second dicing groove G3 and the bottom B1 is longer, making it easier to detect the edge portion E1.

[0046] In contrast, as shown in FIGS. 7 and 8, when the depths of the check groove G1 and the first dicing groove G2 are approximately the same, the edge portion E1 becomes shorter, and its length approaches zero. Furthermore, as shown in FIGS. 9 and 10, when the first dicing groove G2 is deeper than the check groove G1, the second dicing groove G3 and the bottom B1 of the check groove G1 become separated. Therefore, the position of the second dicing groove G3 cannot be detected by detecting the position of the edge portion E1. Therefore, in this embodiment, it is preferable to make the cutting depth of the check groove G1 deeper than the cutting depth of the first dicing groove G2.

[0047] When inspecting the dicing groove G3, it is not necessary to make the second blade 16-2 reach the dicing tape T to completely separate the workpiece W. For example, the second blade 16-2 may not reach the dicing tape T in at least a portion of the dicing groove G3.

[0048] According to this embodiment, by utilizing the check groove G1, the second dicing groove G3 can be detected accurately and easily when a step cut is performed.

[0049] In FIG. 3, the check groove G1 is formed in a region approximately in the center of the surface Wa of the workpiece W, but the present invention is not limited to this. The check groove G1 may be formed, for example, in a peripheral region of the surface Wa of the workpiece W, for example, in a region not used as a device. The formation region of the check groove G1 may be determined depending on the type of device or the required accuracy of dicing. For example, if the required accuracy of dicing is high, the check groove G1 may be formed in a device region used as a device or a region close to this.

[0050] In addition, in this embodiment, the check groove G1 is formed before the first dicing groove G2 and the second dicing groove G3, but it may be formed after the first dicing groove G2 and the second dicing groove G3 are formed. Furthermore, the check groove G1 does not need to be perpendicular to the first dicing groove G2 and the second dicing groove G3, but may intersect with them or at least partially overlap with them, for example.

[0051] [Second embodiment] Next, a second embodiment of the dicing groove inspection method will be described. In the following description, the same components as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

[0052] In the first embodiment described above, a check groove G1 was formed, but in the second embodiment, the formation of the check groove G1 is omitted by utilizing the shape of the workpiece W. That is, if the workpiece W has a recessed shape deeper than the first dicing groove G2 at the position where the first dicing groove G2 and the second dicing groove G3 are to be formed, the Y-direction positions of the first dicing groove G2 and the second dicing groove G3 can be confirmed in the region of this recessed shape, and therefore the formation of the check groove G1 can be omitted.

[0053] In the following description, a case will be described in which the peripheral trimming region SR of the workpiece edge portion (periphery) WL is used as an example of a concave region.

[0054] 11 and 12 are a perspective view and a plan view, respectively, showing a second embodiment of the dicing groove inspection method.

[0055] When dicing a workpiece W, a grinding process is performed after the dicing process to thin the workpiece W using a grinding machine (grinder). In this grinding process, to prevent the peripheral edge of the workpiece W from becoming knife-edge-like, as shown in FIG. 11, trimming of the area near the workpiece edge (periphery) WL may be performed before dicing. In this embodiment, instead of forming a check groove G1, the peripheral trimming area SR formed by this trimming is used to detect the second dicing groove G3. Here, the peripheral trimming area SR functions as the cutting portion of the present invention. Furthermore, the trimming process corresponds to the cutting portion forming step of the present invention, and the grinder (not shown) corresponds to the cutting portion forming portion.

[0056] 11, the peripheral trimming region SR is trimmed to a substantially flat shape. Here, the trimming of the peripheral trimming region SR is set to be deeper than the first dicing groove G2.

[0057] 12, when the first dicing groove G2 and the second dicing groove G3 are formed in sequence, an edge portion E3 is formed on the flat surface SRa of the peripheral trimming region SR. This edge portion E3 can be detected by the observation unit MS. Therefore, as in the first embodiment, it is possible to evaluate the error in the formation position of the second dicing groove G3 and the state of the second blade 16-2 based on the detection result of the position of the edge portion E3.

[0058] According to this embodiment, by utilizing the peripheral trimming region SR, it is possible to accurately and easily detect the step-cut second dicing grooves G3 without forming the check grooves G1.

[0059] [Third embodiment] Next, a third embodiment of the dicing groove inspection method will be described. In the following description, the same components as those in the first and second embodiments will be denoted by the same reference numerals and the description thereof will be omitted.

[0060] Fig. 13 is a perspective view showing a third embodiment of the dicing groove inspection method, Fig. 14 is a side view of the workpiece, and Fig. 15 is a view seen from the direction of arrow XV in Fig. 14.

[0061] The example shown in Fig. 13 shows a case where trimming of the work edge portion WL is not performed. As shown in Fig. 14, a straight line extending from the center C of the cross section of the work edge portion WL (curved surface portion) (for example, the center when the work edge portion WL is approximated as an arc-shaped surface or a curved surface symmetrical with respect to the X direction) to the end of the second dicing groove G2 is defined as L1.

[0062] The observation unit MS is tilted relative to the Z axis from the straight line L1 (φ1>φ) to detect the second dicing groove G3. In this case, the edge E5 is detected in an area WL1 (see FIG. 15) that can be approximated as a plane at the intersection of the line of sight (arrow XV) of the observation unit MS and the workpiece edge WL. This edge E5 can be detected with high accuracy by the observation unit MS, and based on the detection result of the position of the edge E5, it is possible to evaluate the error in the formation position of the second dicing groove G3 and the state of the second blade 16-2.

[0063] According to this embodiment, even when the peripheral trimming region SR is not formed, the step-cut second dicing grooves G3 can be detected accurately and easily. [Explanation of symbols]

[0064] 10... dicing device, 12-1... first cutting unit, 12-2... second cutting unit, 14-1... first spindle, 14-2... second spindle, 16-1... first blade, 16-2... second blade, CT... table, 50-1... first driving unit, 50-2... second driving unit, MS... observation unit, 52... MS driving unit, 54... table driving unit, 100... control unit, 102... input unit, 104... display unit

Claims

1. forming a first dicing groove on a surface of the workpiece using a first blade; forming a second dicing groove deeper than the first dicing groove along the first dicing groove using a second blade that is thinner than the first blade and different from the first blade; When an axis perpendicular to the surface of the workpiece is defined as the Z axis and an axis along the dicing direction is defined as the X axis, observing the workpiece edge portion using an observation unit inclined with respect to the Z axis relative to a straight line extending from the center of a cross section along the ZX plane of the workpiece edge portion to an end of the second dicing groove, and detecting the edge portion of the second dicing groove; A dicing groove inspection method comprising:

2. a first cutting unit including a first blade that forms a first dicing groove on a surface of the workpiece; a second cutting unit including a second blade thinner than the first blade, which forms a second dicing groove along the first dicing groove and within the first dicing groove, the second dicing groove being deeper than the first dicing groove; an observation unit that observes the work edge portion in an attitude inclined with respect to the Z axis relative to a straight line extending from the center of a cross section along the ZX plane of the work edge portion to an end of the second dicing groove, where an axis perpendicular to the surface of the work is defined as the Z axis and an axis along the dicing direction is defined as the X axis, and detects the edge portion of the second dicing groove; A dicing device comprising:

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