Inspection method of dicing groove 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 apparatus, 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 a workpiece, such as a wafer on which semiconductor devices or electronic components are formed, into individual chips is equipped with a blade that is rotated at high speed by a spindle, a worktable that suctions and holds the workpiece, and an XYZθ drive unit that changes the relative position between the worktable and the blade. In this dicing machine, the blade cuts into the workpiece while the blade and the workpiece are moved relatively by the respective drive units, thereby performing a dicing process (cutting process).

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

[0004] [Patent Document 1] JP 2015-085397 A [Patent Document 2] JP 2015-099026 A 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 one 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, in order 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) for removing metal from the surface of the workpiece and a silicon blade (hereinafter referred to as the second blade) for cutting the silicon layer inside the workpiece. In step cut, 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 step cutting. As shown in FIG. 16, the workpiece is composed of a device layer W1 formed on the front surface side and a silicon layer W2, and a dicing tape T is attached to the back surface side of the silicon layer W2. Reference symbol g1 in the figure is a groove formed when removing the device layer W1 with the first blade, and reference symbol g2 is a groove for cutting the silicon layer W2 with the second blade. As shown in FIG. 16, the edge portion e2 of the groove g2 is inside the groove g1, so it cannot be observed with a microscope. In addition, since the groove g1 is inclined, it is difficult to accurately measure the position with a measuring device.

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

[0009] The present invention has been made in consideration of the above circumstances, and has an object 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 forming a first dicing groove on a surface of a 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 different from the first blade, and observing a concave-shaped region that overlaps with at least a portion of the second dicing groove and is deeper than the first dicing groove using an observation unit, and detecting an edge portion between the second dicing groove and the concave-shaped 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-out portion forming step of forming a cut-out portion as a recessed area.

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

[0013] A dicing groove inspection method according to a fourth aspect of the present invention is characterized in that in the cut portion forming step of the second aspect, the peripheral portion of the workpiece is trimmed deeper than the first dicing groove to form the cut portion.

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

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

[0016] [Figure 1] FIG. 1 is a perspective view showing a dicing device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a control system of the dicing apparatus according to one embodiment of the present invention. [Diagram 3] FIG. 3 is a perspective view showing a first embodiment of a method for inspecting a dicing groove. [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. [Diagram 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 of FIG. [Figure 7] FIG. 7 is a perspective 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 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 method for inspecting dicing grooves. [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 in 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 PREFERRED EMBODIMENTS

[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 a cutting unit 12 (a first cutting unit 12-1 and a second cutting unit 12-2) that performs 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 suffix numbers omitted.

[0020] The table CT has a holding surface parallel to the XY plane, and the workpiece W is adsorbed and held on this holding surface by a vacuum source (vacuum generator, such as an ejector or pump, not shown). The workpiece W is attached to a frame (not shown) via a dicing tape (not shown) having an adhesive layer formed on its surface, and is adsorbed and held on the table CT. The frame to which the dicing tape is attached is held by a frame holding means (not shown) disposed on the table CT. A transport form that does not use a frame may also be used.

[0021] Table CT is attached to a θ table (not shown), and the θ table 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), and the X table 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, respectively, 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, respectively, by a Y drive unit including a motor, a ball screw, etc.

[0023] In this embodiment, the X drive unit, the Y drive unit, and the Z drive unit include a motor and a ball screw, but the present invention is not limited to this. For example, a mechanism for reciprocating linear motion, such as a rack and pinion mechanism, can be used as the X drive unit, the Y drive unit, and the Z drive unit.

[0024] 1, the first cutting section 12-1 includes a first spindle 14-1 and a first blade 16-1, and the second cutting section 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 a blade thicker than the second blade 16-2. As the first blade 16-1 and the second blade 16-2, for example, an electroplated blade in which diamond abrasive grains or CBN (Cubic Boron Nitride) abrasive grains are electroplated with nickel, or a resin blade bonded with resin can be used. 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 and the processing content.

[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 index-fed in the Y1 and Y2 directions and cut-fed in the Z1 and Z2 directions, respectively. The table CT is rotated in the θ direction and cut-fed in the X direction.

[0028] (Dicing equipment control system) FIG. 2 is a block diagram showing a control system of the 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 (e.g., a hard disk, etc.), etc. In the control unit 100, various programs such as a control program stored in the ROM are expanded in the RAM, and the programs expanded in 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 input from a user.

[0032] Display unit 104 is a device that displays a GUI (Graphical User Interface) 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 adsorbed and held 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 XY axes. As a mechanism for moving the observation unit MS, for example, a mechanism capable of reciprocating linear motion, such as a ball screw or a rack and pinion mechanism, can be used. Note that, although the MS driving unit 52 for the observation unit MS is provided in this embodiment, it is also possible to omit the MS driving unit 52. For example, if the observation unit MS is made movable 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 YZ directions, the observation unit MS is moved along the XY 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 YZ directions.

[0037] [First embodiment] Next, a first embodiment of a method for inspecting dicing grooves 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 direction (Y direction) perpendicular to the dicing direction (X direction in FIG. 3) using a first blade 16-1 in a portion of the surface of the workpiece W where a kerf check is to be performed (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 made slightly deeper than the groove G2 formed by 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] Here, 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] Fig. 4 and Fig. 5 are respectively a perspective view and a plan view showing a part of a workpiece in which a check groove and first and second dicing grooves are formed. Fig. 6 is a cross-sectional view taken along the line VI-VI in Fig. 5. The symbol T in Fig. 6 indicates 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 becomes 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] In addition, the edge portion E2 between the first dicing groove G2 and the surface Wa of the workpiece can also be detected by the observation unit MS. Therefore, based on the detection result of the position of the edge portion 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 edges 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 that the edge portion E1 formed where the second dicing groove G3 intersects with the bottom B1 is longer, making it easier to detect the edge portion E1.

[0046] On the other hand, as shown in Figs. 7 and 8, when the depths of the check groove G1 and the first dicing groove G2 are substantially the same, the edge E1 becomes shorter and its length approaches zero. Also, 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 are separated. Therefore, the position of the second dicing groove G3 cannot be detected by detecting the position of the edge 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 using the check groove G1, it is possible to accurately and easily detect the second dicing groove G3 when performing step cuts.

[0049] In addition, 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 according to the type of device or the required accuracy of dicing. For example, when 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 the device region.

[0050] 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. The check groove G1 does not need to be perpendicular to the first dicing groove G2 and the second dicing groove G3, and may, for example, intersect with them or at least partially overlap with them.

[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 are given the same reference numerals and the description thereof will be omitted.

[0052] In the above first embodiment, the check groove G1 is 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 the workpiece W, there is a grinding process in which the workpiece W is thinned using a grinding machine (grinder) after the dicing process. In this grinding process, in order to prevent the peripheral portion of the workpiece W from becoming knife-edge-like, as shown in FIG. 11, trimming of the area near the workpiece edge portion (periphery) WL may be performed in advance before the dicing process. 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. 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 order, 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 groove G3 without forming the check groove 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 are given 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 the work edge portion WL is not trimmed. 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 shape 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 section MS is tilted with respect to the Z axis from the straight line L1 (φ1>φ), and the second dicing groove G3 is detected. In this case, the edge portion E5 is detected in the area WL1 (see FIG. 15) that can be approximated to a plane at the intersection of the line of sight (arrow XV) of the observation section MS and the work edge portion WL. This edge portion E5 can be detected with high accuracy by the observation section MS, and based on the detection result of the position of the edge portion 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 if 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 section, 12-2... second cutting section, 14-1... first spindle, 14-2... second spindle, 16-1... first blade, 16-2... second blade, CT... table, 50-1... first drive section, 50-2... second drive section, MS... observation section, 52... MS drive section, 54... table drive section, 100... control section, 102... input section, 104... display section

Claims

1. forming a first dicing groove on a surface of the workpiece using a first blade; forming a second dicing groove in the first dicing groove along the first dicing groove and deeper than 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 work is defined as a Z-axis and an axis along a dicing direction is defined as an X-axis, the work edge portion is observed using an observation portion 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 portion of the second dicing groove, and an edge portion of the second dicing groove is detected; A dicing groove inspection method comprising:

2. a first cutting unit including a first blade for forming a first dicing groove on a surface of the workpiece; a second cutting unit including a second blade thinner than the first blade, the second blade forming a second dicing groove deeper than the first dicing groove within the first dicing groove along the first dicing groove; an observation unit that observes the work edge portion in a position 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 an edge portion of the second dicing groove; A dicing apparatus comprising:

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