Laser dicing device

Abstract

This laser dicing device (100) comprises: a wafer holding unit (307) for holding a wafer ring structure W; a laser irradiation unit (301) for irradiating the wafer We held by the wafer holding unit with a laser to perform dicing processing on the wafer; a detection unit (304) for detecting a step on the upper surface or the lower surface of the wafer ring structure W held by the wafer holding unit; and a control unit (4) for acquiring the orientation of the front and back surfaces of the wafer ring structure W on the basis of the presence or absence of the step on the upper surface or the lower surface of the wafer ring structure W detected by the detection unit.

Description

Laser dicing equipment

[0001] The present invention relates to a laser dicing device, and more particularly to a laser dicing device equipped with a laser irradiation unit that processes a wafer.

[0002] 2. Description of the Related Art Conventionally, a wafer processing apparatus for processing a wafer has been known, and is disclosed, for example, in Japanese Patent No. 6721473.

[0003] The above-mentioned Japanese Patent No. 6721473 discloses a wafer processing device that irradiates light onto tape attached to a wafer, identifies the type of tape attached to the wafer based on the reflectance of the light reflected by the tape, and processes the wafer using a processing method that corresponds to the identified type of tape.

[0004] Patent No. 6721473

[0005] However, while the wafer processing apparatus of the above-mentioned Patent Publication No. 6721473 can identify the type of tape attached to the wafer and process the wafer using a processing method corresponding to the identified type of tape, it cannot identify the type of tape when light is irradiated onto the wafer from the side opposite the tape attached to the wafer, and therefore cannot process the wafer appropriately. In other words, if the front and back of the wafer are not facing the correct direction, it is difficult to process the wafer appropriately. Therefore, there is a demand for a processing apparatus (laser dicing apparatus) that can identify the front and back of a wafer and process the wafer appropriately depending on the identified front and back of the wafer.

[0006] This invention has been made to solve the above-mentioned problems, and one object of the invention is to provide a laser dicing device that can distinguish the front and back sides of a wafer and process the wafer appropriately depending on the distinguished front and back sides of the wafer.

[0007] A laser dicing device according to one aspect of the present invention includes a wafer holding unit that holds a wafer ring structure including a wafer, a sheet member to which the wafer is attached, and a ring frame that supports the sheet member; a laser irradiation unit that dices the wafer by irradiating a laser onto the wafer held in the wafer holding unit; a detection unit that detects steps on the top or bottom surface of the wafer ring structure held in the wafer holding unit; and a control unit that obtains the orientation of the front and back of the wafer ring structure based on the presence or absence of steps on the top or bottom surface of the wafer ring structure detected by the detection unit.

[0008] As described above, a laser dicing apparatus according to one aspect of the present invention includes a detection unit that detects a step on the top or bottom surface of a wafer ring structure held by a wafer holder, and a control unit that acquires the front and back orientations of the wafer ring structure based on the presence or absence of a step on the top or bottom surface of the wafer ring structure detected by the detection unit. This allows the front and back orientations of the wafer ring structure to be acquired based on the step on the wafer ring structure detected by the detection unit, making it easy to determine the front and back orientations of the wafer. As a result, the front and back orientations of the wafer can be determined and the wafer can be appropriately processed according to the determined front and back orientations. Here, when dicing a wafer by irradiating it with a laser, there are two methods: irradiating the laser from the front side of the wafer (opposite the sheet member) and irradiating the laser from the back side of the wafer (the sheet member side). In other words, the front and back orientations of wafers loaded into the laser dicing apparatus are not limited to one. In such a laser dicing apparatus, the present invention can distinguish the front and back orientations of the wafer, making it possible to appropriately process the wafer according to the determined front and back orientations of the wafer.

[0009] In the laser dicing apparatus according to the above aspect, the detection unit is preferably configured to detect a step between the ring frame of the wafer ring structure and the sheet member on the ring frame, and the control unit acquires the front / back orientation of the wafer ring structure based on the presence or absence of a step between the ring frame and the sheet member on the ring frame detected by the detection unit. With this configuration, the detection unit detects the step on the ring frame, which is positioned at a fixed position relative to the wafer holder, so that the presence or absence of the step can be detected more reliably, unlike when detecting a step on an object such as a wafer, whose step position varies depending on its size. This allows for more reliable determination of the front / back of the wafer ring structure.

[0010] In the laser dicing apparatus according to the above aspect, the detection unit preferably detects steps on the top or bottom surface of the wafer ring structure at multiple locations, and the control unit acquires the front and back orientations of the wafer ring structure based on the multiple detection results detected by the detection unit. With this configuration, erroneous detection can be reduced compared to when the front and back orientations of the wafer ring structure are determined based on the detection result of a step on the wafer ring structure at a single location, and therefore the front and back orientations of the wafer ring structure can be determined more accurately.

[0011] In the laser dicing apparatus according to the above aspect, the control unit preferably acquires processing condition data for the wafer and determines whether the front and back orientations of the wafer ring structure acquired based on the detection results by the detection unit are the same as the front and back orientations of the wafer ring structure based on the processing condition data. With this configuration, it is possible to determine whether the wafer ring structure is arranged with its front and back orientations in accordance with the processing conditions, thereby effectively preventing laser dicing from being performed on a wafer ring structure with an incorrect front and back orientation.

[0012] In the laser dicing apparatus in which the control unit determines whether the front-back orientation of the wafer ring structure obtained based on the detection result by the detection unit is the same as the front-back orientation of the wafer ring structure based on the processing condition data, the control unit preferably controls the display unit to display a notification when the front-back orientation of the wafer ring structure obtained based on the detection result by the detection unit differs from the front-back orientation of the wafer ring structure based on the processing condition data. With this configuration, it is possible to visually easily allow an operator to recognize that the wafer ring structure has been set with the wrong front-back orientation.

[0013] In the laser dicing apparatus in which the control unit determines whether the front and back orientations of the wafer ring structure obtained based on the detection results by the detection unit are the same as the front and back orientations of the wafer ring structure based on the processing condition data, preferably, the control unit controls the detection unit to detect the presence or absence of steps in other parts of the wafer ring structure when the front and back orientations of the wafer ring structure obtained based on the detection results by the detection unit differ from the front and back orientations of the wafer ring structure based on the processing condition data. With this configuration, the front and back of the wafer ring structure can be determined based on steps at multiple positions on the wafer ring structure, thereby effectively suppressing erroneous detection.

[0014] In the laser dicing apparatus in which the control unit determines whether the front and back orientations of the wafer ring structure obtained based on the detection results of the detection unit are the same as the front and back orientations of the wafer ring structure based on the processing condition data, the apparatus preferably further includes an inversion unit that inverts the front and back of the wafer ring structure, and the control unit controls the inversion unit to invert the front and back of the wafer ring structure when the front and back orientations of the wafer ring structure obtained based on the detection results of the detection unit differ from the front and back orientations of the wafer ring structure based on the processing condition data. With this configuration, the wafer ring structure can be reset to the appropriate front and back orientation, allowing the laser dicing process to continue without interruption.

[0015] In this case, preferably, after the reversing unit has reversed the wafer ring structure, the control unit again controls the detection unit to obtain the orientation of the wafer ring structure based on the presence or absence of a step in the wafer ring structure. With this configuration, it is possible to confirm whether the reversing unit has reversed the wafer ring structure to the appropriate orientation, thereby more reliably performing appropriate processing on the wafer.

[0016] In the laser dicing apparatus in which the control unit determines whether the front and back orientations of the wafer ring structure acquired based on the detection results of the detection unit are the same as the front and back orientations of the wafer ring structure based on the processing condition data, preferably, when the front and back orientations of the wafer ring structure acquired based on the detection results of the detection unit differ from the front and back orientations of the wafer ring structure based on the processing condition data, the control unit changes the processing condition data to match the front and back orientations of the wafer ring structure held by the wafer holder, and controls the laser irradiation unit to irradiate the wafer with a laser for dicing. With this configuration, by changing the processing conditions, it is possible to process a wafer ring structure with an incorrect front and back orientation, so that the laser dicing process can be continued without interruption.

[0017] The laser dicing apparatus according to the above aspect preferably further includes an imaging unit that images an alignment mark provided on the wafer, and the control unit performs control to acquire the front and back orientations of the wafer ring structure based on the presence or absence of a step in the wafer ring structure when the alignment mark cannot be detected based on the imaging result by the imaging unit. With this configuration, it can be confirmed whether the inability to detect the alignment mark is due to the front and back orientation of the wafer ring structure being incorrect.

[0018] In the laser dicing apparatus according to the above aspect, the control unit preferably performs control to acquire the front and back orientations of the wafer ring structure based on the presence or absence of a step in the wafer ring structure when the processing condition data for the wafer is switched. With this configuration, when the processing conditions are switched, it can be determined whether the front and back orientations of the wafer ring structure are set appropriately for the switched processing conditions.

[0019] The laser dicing apparatus according to the above aspect preferably further includes a housing that covers the wafer holding unit and the laser irradiation unit and has a door that opens to the interior, and the control unit performs control to obtain the front and back orientations of the wafer ring structure based on the presence or absence of steps in the wafer ring structure when the housing door is opened and an operator performs work. With this configuration, if the front and back orientations of the wafer ring structure are inappropriate due to human error during work by the operator, it is possible to prevent processing from being performed with the wafer ring structure in an inappropriate front and back orientation.

[0020] The laser dicing apparatus according to the above aspect preferably further includes a distance measuring sensor that measures the distance from the laser irradiation unit to the wafer held by the wafer holding unit, the detection unit including the distance measuring sensor, and the control unit detecting the presence or absence of a step in the wafer ring structure by measuring the distance from the upper surface or lower surface of the wafer ring structure with the distance measuring sensor. With this configuration, the step in the wafer ring structure can be detected using the distance measuring sensor that measures the distance from the laser irradiation unit to the wafer held by the wafer holding unit, eliminating the need for a separate member for step detection.

[0021] According to the present invention, as described above, the front and back sides of the wafer can be determined and the wafer can be appropriately processed depending on the determined front and back sides of the wafer.

[0022] FIG. 1 is a plan view showing a laser dicing apparatus according to an embodiment; FIG. 2 is a plan view showing a wafer to be laser diced in the laser dicing apparatus according to an embodiment; FIG. 3 is a block diagram showing the control configuration of the laser dicing apparatus according to an embodiment; FIG. 4 is a diagram showing a state in which a wafer of a wafer ring structure according to an embodiment is located below a sheet member; FIG. 5 is a diagram showing a state in which a wafer of a wafer ring structure according to an embodiment is located above a sheet member; FIG. 6 is a plan view showing alignment marks of a wafer according to an embodiment; FIG. 7 is a flowchart for explaining a front / back determination process by a control unit of a laser processing apparatus according to an embodiment; FIG. 8 is a flowchart for explaining a first example of a front / back determination start process by a control unit of a laser processing apparatus according to an embodiment; FIG. 9 is a flowchart for explaining a second example of a front / back determination start process by a control unit of a laser processing apparatus according to an embodiment;

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0024] The configuration of a laser dicing apparatus 100 according to an embodiment of the present invention will be described with reference to FIGS.

[0025] (Configuration of Laser Dicing Apparatus) As shown in FIG. 1, the laser dicing apparatus 100 is configured to perform laser dicing processing to form a modified layer inside the wafer We for dividing the wafer We.

[0026] The laser dicing apparatus 100 includes a cassette unit 1, a wafer transport unit 2, a dicing unit 3, and a control unit 4. The laser dicing apparatus 100 also includes a housing 100a that covers the chuck table unit 307 and the laser irradiation unit 301. The housing 100a is provided with a door 100b that opens the interior.

[0027] The cassette unit 1 is configured to accommodate a plurality of cassettes each containing a wafer ring structure W, each of which includes a wafer We attached to a sheet member Wt (see FIG. 2) and a ring frame Wf. As shown in FIG. 4, the wafer ring structure W includes a wafer We, a sheet member Wt to ​​which the wafer We is attached, and a ring frame Wf that supports the sheet member Wt. The sheet member Wt is attached to one side of the ring frame Wf. The ring frame Wf is annular. The wafer We is disposed inside the annular ring frame Wf. The wafer We is attached to the surface of the sheet member Wt facing the ring frame Wf.

[0028] The cassette unit 1 includes a plurality of cassette placement units 11 and a Z-direction movement mechanism 12 .

[0029] The multiple cassette mounting units 11 include one cassette mounting unit and another cassette mounting unit. A cassette containing a plurality of unprocessed wafers We is mounted on one cassette mounting unit. Furthermore, a cassette containing a plurality of processed wafers We is mounted on the other cassette mounting unit. The Z-direction movement mechanism 12 is configured to move the multiple cassette units 1 integrally in the Z1 direction or the Z2 direction. The Z-direction movement mechanism 12 includes, for example, a linear conveyor module or a drive unit having a ball screw and a motor with an encoder.

[0030] The wafer transport unit 2 is configured to transport the wafer ring structure W between the cassette unit 1 and the dicing unit 3. Specifically, the wafer transport unit 2 has a clamp hand unit 21, a Y-direction movement mechanism 22, rail units 23 and 24, a transfer head unit 25, a transfer head unit 26, and a Z-direction movement mechanism 27.

[0031] The clamp hand unit 21 is configured to clamp the ring frame Wf of the wafer ring structure W and remove it from the cassette unit 1 or store it in the cassette unit 1. The clamp hand unit 21 is moved in each of the Y1 direction and the Y2 direction by a Y-direction movement mechanism 22. The Y-direction movement mechanism 22 has, for example, a linear conveyor module or a drive unit having a ball screw and a motor with an encoder.

[0032] The clamp hand unit 21 transports the wafer ring structure W removed from the cassette unit 1 to the rail unit 23 using the Y-direction movement mechanism 22. The clamp hand unit 21 transports the wafer ring structure W removed from the cassette unit 1 to the rail unit 24 using the Y-direction movement mechanism 22. The clamp hand unit 21 stores the processed wafer ring structure W placed on the rail unit 24 into the cassette unit 1 using the Y-direction movement mechanism 22.

[0033] Rail portion 23 is configured to support, from the Z2 direction, the wafer ring structure W placed by clamp hand portion 21. Rail portion 24 is configured to support, from the Z2 direction, the wafer ring structure W placed by clamp hand portion 21. Rail portion 23 and rail portion 24 are arranged side by side in this order from the Y2 direction side toward the Y1 direction side.

[0034] The rail portion 24 is provided with an inversion portion 241 that grips the wafer ring structure W and inverts the wafer ring structure W upside down (front and back). The inversion portion 241 includes a drive unit such as a motor and a gripping portion that grips the wafer ring structure W.

[0035] Each of the transfer and placement head units 25 and 26 is configured to adsorb the ring frame Wf of the wafer ring structure W. Each of the transfer and placement head units 25 and 26 is provided with an adsorption unit having a suction hole or the like for adsorbing the ring frame Wf of the wafer ring structure W. The Z-direction movement mechanism 27 is configured to independently move each of the transfer and placement head units 25 and 26 in the Z1 direction or the Z2 direction. The Z-direction movement mechanism 27 includes, for example, a linear conveyor module or a drive unit having a ball screw and a motor with an encoder.

[0036] 1, the dicing unit 3 includes a laser irradiation unit 301, a Z-direction movement unit 302, a Y-direction movement unit 303, a distance measurement sensor 304, an X-direction movement unit 306, a chuck table unit 307, a low-magnification image capturing unit 308, a high-magnification image capturing unit 309, a Z-direction movement mechanism 310, and a frame 311. The chuck table unit 307 is an example of the "wafer holding unit" in the claims.

[0037] The laser irradiation unit 301 is configured to process the wafer We by irradiating a laser beam toward an irradiation position. The laser irradiation unit 301 dices the wafer We by irradiating the wafer We held on the chuck table unit 307 with a laser. That is, the laser irradiation unit 301 is configured to form a modified layer inside the wafer We by irradiating the wafer We, on which a plurality of semiconductor chips Ch (see FIG. 2) are provided, with a laser beam.

[0038] The laser irradiation unit 301 is configured to irradiate the wafer We with a laser along each of a plurality of streets Ws (see FIG. 2 ) on the wafer We while moving the wafer We relative to the laser irradiation unit 301 using a chuck table 307. The laser irradiation unit 301 is attached to a frame 311 via a Z-direction moving unit 302. The laser irradiation unit 301 is movable in the Z1 and Z2 directions by the Z-direction moving unit 302, but its horizontal position is fixed. The Z-direction moving unit 302 has, for example, a linear conveyor module or a drive unit having a ball screw and a motor with an encoder. A processing line to be processed by the laser is set along each of the plurality of streets Ws.

[0039] 1 , the Y-direction moving unit 303 is configured to move the X-direction moving unit 306 and the chuck table unit 307 in the Y1 direction and the Y2 direction, respectively. The Y-direction moving unit 303 is attached to the base 5. The Y-direction moving unit 303 has a drive unit 331, a first guide rail 332, and a second guide rail 333.

[0040] The drive unit 331 is a drive unit that generates a drive force that moves the X-direction movement unit 306 in the Y1 direction and the Y2 direction. The drive unit 331 has, for example, a linear conveyor module or a motor with a ball screw and an encoder.

[0041] The first guide rail 332 and the second guide rail 333 each extend along the Y direction so as to guide movement of the X-direction moving unit 306 in the Y direction. The first guide rail 332 and the second guide rail 333 are arranged in X direction so as to sandwich the single drive unit 331. When viewed from the Z1 direction side, the first guide rail 332 and the second guide rail 333 are arranged symmetrically with respect to a line extending in the Y direction that passes through the center of the X-direction moving unit 306 in the X direction.

[0042] The first guide rail 332 is disposed on the X1 direction side of the single drive unit 331. The end portion of the X1 direction side of the X-direction moving unit 306 is attached to the first guide rail 332 so as to be movable in the Y direction. The second guide rail 333 is disposed on the X2 direction side of the single drive unit 331. The end portion of the X2 direction side of the X-direction moving unit 306 is attached to the second guide rail 333 so as to be movable in the Y direction.

[0043] The distance measurement sensor 304 measures the distance to the wafer We held on the chuck table 307 relative to the laser irradiation unit 301. The distance measurement sensor 304 measures the distance to the measurement object by emitting laser light and receiving the laser light reflected by the measurement object. The distance measurement sensor 304 is attached to a frame 311 to which the laser irradiation unit 301 is attached. The distance measurement sensor 304 is attached near the laser irradiation unit 301. The distance measurement sensor 304 is an example of a "detection unit" in the claims.

[0044] The distance measuring sensor 304 also detects steps on the upper or lower surface of the wafer ring structure W held on the chuck table portion 307. That is, the distance measuring sensor 304 detects steps on the wafer ring structure W by measuring the distance while moving relatively above the wafer ring structure W.

[0045] As shown in FIGS. 4 and 5, the distance measuring sensor 304 is configured to detect a step between the ring frame Wf of the wafer ring structure W and the sheet member Wt on the ring frame Wf.

[0046] The distance measuring sensor 304 also detects steps on the upper or lower surface of the wafer ring structure W at multiple locations.

[0047] 1, the X-direction moving unit 306 is configured to move the chuck table unit 307 in each of the X1 and X2 directions. The X-direction moving unit 306 has, for example, a linear conveyor module or a drive unit having a ball screw and a motor with an encoder.

[0048] The X-direction moving section 306 is attached to the Y-direction moving section 303. As a result, the X-direction moving section 306 is moved in the Y1 direction and the Y2 direction by the Y-direction moving section 303.

[0049] The chuck table 307 holds the wafer ring structure W. Specifically, the chuck table 307 is configured to hold the wafer We attached to the sheet member Wt by suction. The chuck table 307 is configured to rotate about a rotation axis along the vertical direction. This allows the chuck table 307 to rotate while holding the ring frame Wf. The chuck table 307 is also configured to be movable in the horizontal direction by the Y-direction moving unit 303 and the X-direction moving unit 306.

[0050] The low-magnification imaging unit 308 and the high-magnification imaging unit 309 are each configured to capture an image of the wafer We held on the chuck table unit 307. The low-magnification imaging unit 308 and the high-magnification imaging unit 309 are each a near-infrared imaging camera. The low-magnification imaging unit 308 and the high-magnification imaging unit 309 are each attached to a frame 311 via a Z-direction movement mechanism 310. The Z-direction movement mechanism 310 is configured to move the low-magnification imaging unit 308 and the high-magnification imaging unit 309 integrally in each of the Z1 direction and the Z2 direction. The Z-direction movement mechanism 310 includes, for example, a linear conveyor module or a drive unit having a ball screw and a motor with an encoder.

[0051] The high-magnification imaging unit 309 captures an image of an alignment mark M (see FIG. 6) provided on the wafer We in order to align the wafer We. Then, based on the image capture result of the alignment mark M, the position of the chuck table unit 307 in the X and Y directions is adjusted.

[0052] 3, the control unit 4 is configured to control each of the cassette unit 1, wafer transport unit 2, and dicing unit 3 to process the wafer We in the laser dicing apparatus 100. The control unit 4 is electrically connected to each of the cassette unit 1, wafer transport unit 2, laser irradiation unit 301, Z-direction movement unit 302, Y-direction movement unit 303, distance measurement sensor 304, X-direction movement unit 306, chuck table unit 307, low-magnification imaging unit 308, high-magnification imaging unit 309, and Z-direction movement mechanism 310.

[0053] Specifically, the control unit 4 includes a CPU (Central Processing Unit) 41 and a memory 42 having a ROM (Read Only Memory) and a RAM (Random Access Memory). The control unit 4 also includes a storage unit 43. The storage unit 43 stores a control program for the laser dicing apparatus 100, including the processing of the wafer We by laser. The storage unit 43 also stores processing condition data 431, which sets conditions for processing the wafer We.

[0054] The processing condition data 431 includes various conditions (settings) for processing the wafer We. For example, the processing condition data 431 includes information on conditions such as the orientation of the wafer We during processing, the position of the street on the wafer We to be processed (processing position), the depth position of the wafer We to be processed (height position from the surface), the intensity of the laser used for processing, and the movement speed during processing.

[0055] In this embodiment, the control unit 4 determines the front / back orientation of the wafer ring structure W based on the presence or absence of a step on the top or bottom surface of the wafer ring structure W detected by the distance measurement sensor 304. For example, as shown in FIG. 4 , when there is no step, the control unit 4 determines that the wafer ring structure W faces down and that the wafer We is located below the sheet member Wt. Also, as shown in FIG. 5 , when there is a step, the control unit 4 determines that the wafer ring structure W faces up and that the wafer We is located above the sheet member Wt.

[0056] The control unit 4 also detects the presence or absence of a step on the wafer ring structure W by measuring the distance to the upper or lower surface of the wafer ring structure W using the distance measurement sensor 304. That is, the control unit 4 determines that there is no step if the distance measured by the distance measurement sensor 304 is within a predetermined range. On the other hand, the control unit 4 determines that there is a step if the distance measured by the distance measurement sensor 304 changes beyond the predetermined range.

[0057] The control unit 4 also acquires the front / back orientation of the wafer ring structure W based on the presence or absence of a step on the ring frame Wf between the ring frame Wf and the sheet member Wt detected by the distance measurement sensor 304. That is, the control unit 4 controls the distance measurement sensor 304 to measure the position on the ring frame Wf and detects the step. Then, the control unit 4 acquires the front / back orientation of the wafer ring structure W based on the presence or absence of a step in the ring frame Wf portion.

[0058] The control unit 4 may also obtain the front and back orientations of the wafer ring structure W based on multiple detection results obtained by the distance measurement sensor 304. That is, the control unit 4 controls the distance measurement sensor 304 to measure multiple positions on the ring frame Wf of the wafer ring structure W and detects steps at each of the positions. The control unit 4 then obtains the front and back orientations of the wafer ring structure W based on the presence or absence of steps at multiple locations on the ring frame Wf. For example, if there are both cases where it is determined that there is a step and cases where it is determined that there is no step, the control unit 4 uses the determination result that is more prevalent. Furthermore, the control unit 4 may also issue an error notification if there are both cases where it is determined that there is a step and cases where it is determined that there is no step.

[0059] Furthermore, the control unit 4 acquires the processing condition data 431 for the wafer We, and determines whether the front and back orientations of the wafer ring structure W acquired based on the detection results of the distance measurement sensor 304 are the same as the front and back orientations of the wafer ring structure W based on the processing condition data 431. In other words, the control unit 4 determines whether the front and back orientations of the wafer We to be laser processed now match the front and back orientations set forth in the processing conditions.

[0060] Furthermore, when the front-back orientation of the wafer ring structure W acquired based on the detection result by the distance measurement sensor 304 differs from the front-back orientation of the wafer ring structure W based on the processing condition data 431, the control unit 4 controls the display unit 6 to display a warning that the front and back of the wafer ring structure W are reversed.

[0061] In addition, the control unit 4 may control the distance measurement sensor 304 to detect whether or not there is a step in another part of the wafer ring structure W when the orientation of the front and back of the wafer ring structure W obtained based on the detection results by the distance measurement sensor 304 differs from the orientation of the front and back of the wafer ring structure W based on the processing condition data 431.

[0062] Furthermore, when the front-back orientation of the wafer ring structure W acquired based on the detection results of the distance measurement sensor 304 differs from the front-back orientation of the wafer ring structure W based on the processing condition data 431, the control unit 4 controls the reversing unit 241 to reverse the front and back of the wafer ring structure W. Specifically, when the front-back orientation of the wafer ring structure W differs from the processing conditions, the control unit 4 transfers the wafer ring structure W from the chuck table 307 to the reversing unit 241 using the transfer head unit 25 or the transfer head unit 26. Then, the reversing unit 241 reverses the wafer ring structure W. Thereafter, the transfer head unit 25 or the transfer head unit 26 transfers the wafer ring structure W from the reversing unit 241 to the chuck table 307.

[0063] In this case, the control unit 4 reverses the front and back of the wafer ring structure W using the reversing unit 241, and then again controls the distance measuring sensor 304 to obtain the front and back orientation of the wafer ring structure W based on the presence or absence of a step in the wafer ring structure W.

[0064] In addition, when the orientation of the front and back of the wafer ring structure W obtained based on the detection results by the distance measurement sensor 304 differs from the orientation of the front and back of the wafer ring structure W based on the processing condition data 431, the control unit 4 changes the processing condition data 431 to match the orientation of the front and back of the wafer ring structure W held on the chuck table unit 307, and controls the laser irradiation unit 301 to irradiate the wafer We with a laser to perform dicing processing.

[0065] In addition, when the orientation of the front and back of the wafer ring structure W obtained based on the detection results by the distance measurement sensor 304 differs from the orientation of the front and back of the wafer ring structure W based on the processing condition data 431, the control unit 4 may perform either control to invert the structure or control to change the processing conditions.

[0066] Furthermore, when the alignment mark M (see FIG. 6 ) cannot be detected based on the imaging results obtained by the high-magnification imaging unit 309, the control unit 4 performs control to acquire the front / back orientation of the wafer ring structure W based on the presence or absence of a step on the wafer ring structure W. In other words, the control to determine the front / back of the wafer ring structure W does not always need to be performed before processing. For example, when the alignment mark M cannot be detected, the control to determine the front / back of the wafer ring structure W is performed.

[0067] Furthermore, for example, when the processing condition data 431 for the wafer is switched, the control unit 4 performs control to acquire the front / back orientation of the wafer ring structure W based on the presence or absence of a step in the wafer ring structure W. In other words, control to determine the front / back orientation is performed for the first wafer ring structure W after the processing conditions are switched.

[0068] Furthermore, for example, when the door 100b of the housing 100a is opened and an operator performs work, the control unit 4 performs control to acquire the front and back orientations of the wafer ring structure W based on the presence or absence of a step in the wafer ring structure W. In other words, control is performed to determine the front and back orientations of the wafer ring structure W when work by an operator has been performed.

[0069] (Front and Back Determination Processing) The processing performed by the control unit 4 to determine the front and back orientation of the wafer ring structure W will be described with reference to FIG.

[0070] 7, the wafer ring structure W is transferred to the chuck table 307. In step S2, any steps on the wafer ring structure W are detected, and the front and back sides of the wafer ring structure W are obtained based on the step detection.

[0071] In step S3, it is determined whether the front and back orientations of the wafer ring structure W acquired based on the detection results by the distance measurement sensor 304 are consistent (the same or not) with the front and back orientations of the wafer ring structure W based on the processing condition data 431. If the front and back orientations of the wafer ring structure W acquired based on the detection results by the distance measurement sensor 304 match (match) the front and back orientations of the wafer ring structure W based on the processing condition data 431, the process of determining the front and back orientations of the wafer ring structure W is terminated. If the front and back orientations of the wafer ring structure W acquired based on the detection results by the distance measurement sensor 304 do not match (match) the front and back orientations of the wafer ring structure W based on the processing condition data 431, the process proceeds to step S5.

[0072] In step S5, at least one of a process of notifying an error, a process of inverting the wafer ring structure W, and a process of changing the processing conditions is executed.

[0073] (First Example of Front / Back Determination Start Process) A first example of a process for starting determination of the front / back orientation of the wafer ring structure W by the control unit 4 will be described with reference to FIG.

[0074] 8, it is determined whether or not a detection error has occurred for the alignment mark M. If a detection error for the alignment mark M has occurred, the process proceeds to step S12. If a detection error for the alignment mark M has not occurred, the process of determining the front and back orientations of the wafer ring structure W is not started.

[0075] In step S12, a process for determining the front and back orientation of the wafer ring structure W is started.

[0076] (Front / Back Determination Start Process (Second Example)) A second example of the process for starting determination of the front / back orientation of the wafer ring structure W by the control unit 4 will be described with reference to FIG.

[0077] 9, a change in processing conditions is accepted. In step S22, automatic operation of processing the wafer We is started. In step S13, processing for determining the front and back orientations of the wafer ring structure W is started.

[0078] (Front / Back Determination Start Process (Third Example)) A third example of the process for starting determination of the front / back orientation of the wafer ring structure W by the control unit 4 will be described with reference to FIG.

[0079] 10, it is detected that the door 100b has been opened and an operator has performed an operation. Then, when the operator has finished the operation and the door 100b is closed, automatic operation of processing the wafers We is started (restarted) in step S32. In step S33, a process of determining the front and back orientations of the wafer ring structure W is started.

[0080] (Effects of this embodiment) In this embodiment, the following effects can be obtained.

[0081] As described above, this embodiment includes a distance measuring sensor 304 that detects a step on the upper or lower surface of the wafer ring structure W held on the chuck table 307, and a control unit 4 that acquires the front and back orientations of the wafer ring structure W based on the presence or absence of a step on the upper or lower surface of the wafer ring structure W detected by the distance measuring sensor 304. This allows the front and back orientations of the wafer ring structure W to be acquired based on the step on the wafer ring structure W detected by the distance measuring sensor 304, making it possible to easily determine the front and back orientations of the wafer We. As a result, the front and back orientations of the wafer We can be determined and the wafer We can be appropriately processed according to the determined front and back orientations of the wafer We. Here, when dicing the wafer We by irradiating it with a laser, there are two methods: irradiating the laser from the front side of the wafer We and irradiating the laser from the back side of the wafer We. In other words, the front and back orientations of the wafer We loaded into the laser dicing apparatus 100 are not always the same. In this embodiment, such a laser dicing apparatus 100 can distinguish the front and back sides of the wafer We, and therefore can appropriately process the wafer We according to the distinguished front and back sides of the wafer We.

[0082] In this embodiment, as described above, the distance measuring sensor 304 is configured to detect a step between the ring frame Wf of the wafer ring structure W and the sheet member Wt on the ring frame Wf. The control unit 4 acquires the front / back orientation of the wafer ring structure W based on the presence or absence of a step between the ring frame Wf and the sheet member Wt on the ring frame Wf detected by the distance measuring sensor 304. This allows the distance measuring sensor 304 to detect a step on the ring frame Wf, which is positioned at a fixed position relative to the chuck table 307. This makes it possible to more reliably detect the presence or absence of a step, unlike detecting a step on an object such as a wafer We, whose step position varies depending on its size. This allows for more reliable determination of the front / back of the wafer ring structure W.

[0083] Furthermore, in this embodiment, as described above, the distance measuring sensor 304 detects steps on the upper or lower surface of the wafer ring structure W at multiple locations. Furthermore, the control unit 4 obtains the front / back orientation of the wafer ring structure W based on multiple detection results obtained by the distance measuring sensor 304. This makes it possible to reduce false detections compared to when determining the front / back orientation of the wafer ring structure W based on the detection result of a step on the wafer ring structure W at one location, and therefore makes it possible to more accurately determine the front / back orientation of the wafer ring structure W.

[0084] Furthermore, in this embodiment, as described above, the control unit 4 acquires the processing condition data 431 for the wafer We, and determines whether the front and back orientations of the wafer ring structure W acquired based on the detection results of the distance measurement sensor 304 are the same as the front and back orientations of the wafer ring structure W based on the processing condition data 431. This makes it possible to determine whether the wafer ring structure W is arranged with its front and back orientations in accordance with the processing conditions, thereby effectively preventing laser dicing from being performed on a wafer ring structure W with an incorrect front and back orientation.

[0085] Furthermore, in this embodiment, as described above, the control unit 4 controls the display unit 6 to display and notify the operator when the front-back orientation of the wafer ring structure W acquired based on the detection result by the distance measurement sensor 304 differs from the front-back orientation of the wafer ring structure W based on the processing condition data 431. This allows the operator to easily and visually recognize that the wafer ring structure W has been set with the wrong front-back orientation.

[0086] Furthermore, in this embodiment, as described above, when the front / back orientation of the wafer ring structure W acquired based on the detection result by the distance measuring sensor 304 differs from the front / back orientation of the wafer ring structure W based on the processing condition data 431, the control unit 4 controls the distance measuring sensor 304 to detect the presence or absence of a step in another portion of the wafer ring structure W. This makes it possible to determine the front / back of the wafer ring structure W based on the step differences at multiple positions on the wafer ring structure W, thereby effectively suppressing erroneous detection.

[0087] Furthermore, in this embodiment, as described above, there is provided an inversion unit 241 that inverts the front and back of the wafer ring structure W. Furthermore, when the front and back orientation of the wafer ring structure W acquired based on the detection result by the distance measurement sensor 304 differs from the front and back orientation of the wafer ring structure W based on the processing condition data 431, the control unit 4 controls the inversion unit 241 to invert the front and back of the wafer ring structure W. This makes it possible to reset the wafer ring structure W in the appropriate front and back orientation, allowing the laser dicing process to continue without interruption.

[0088] Furthermore, in this embodiment, as described above, after the reversing unit 241 has reversed the wafer ring structure W, the control unit 4 again controls the distance measuring sensor 304 to acquire the orientation of the wafer ring structure W based on the presence or absence of a step in the wafer ring structure W. This makes it possible to confirm whether the reversing unit 241 has reversed the wafer ring structure W to the appropriate orientation, thereby more reliably performing appropriate processing on the wafer We.

[0089] Furthermore, in this embodiment, as described above, when the front / back orientation of the wafer ring structure W acquired based on the detection result by the distance measurement sensor 304 differs from the front / back orientation of the wafer ring structure W based on the processing condition data 431, the control unit 4 changes the processing condition data 431 to match the front / back orientation of the wafer ring structure W held on the chuck table unit 307, and controls the laser irradiation unit 301 to irradiate the wafer We with a laser for dicing. In this way, by changing the processing conditions, it is possible to process the wafer ring structure W with the incorrect front / back orientation, and therefore the laser dicing process can be continued without interruption.

[0090] Furthermore, in this embodiment, as described above, a high-magnification imaging unit 309 is provided that captures an image of the alignment mark M provided on the wafer We. Furthermore, when the alignment mark M cannot be detected based on the imaging results obtained by the high-magnification imaging unit 309, the control unit 4 performs control to acquire the front and back orientations of the wafer ring structure W based on the presence or absence of a step in the wafer ring structure W. This makes it possible to confirm whether the inability to detect the alignment mark M is due to the front and back orientations of the wafer ring structure W being incorrect.

[0091] Furthermore, in this embodiment, as described above, when the processing condition data 431 for the wafer is switched, the control unit 4 performs control to acquire the front and back orientations of the wafer ring structure W based on the presence or absence of a step in the wafer ring structure W. This makes it possible to determine, when the processing conditions are switched, whether the front and back orientations of the wafer ring structure W are set appropriately for the switched processing conditions.

[0092] Furthermore, in this embodiment, as described above, a housing 100a is provided that covers the chuck table 307 and the laser irradiation unit 301 and has a door 100b that opens to the interior. Furthermore, when the door 100b of the housing 100a is opened and an operator performs work, the control unit 4 performs control to acquire the front and back orientations of the wafer ring structure W based on the presence or absence of steps in the wafer ring structure W. This makes it possible to prevent processing from being performed with the wafer ring structure W facing in the incorrect direction when the front and back orientations of the wafer ring structure W are inappropriate due to a human error caused by the operator's work.

[0093] In this embodiment, as described above, the distance measuring sensor 304 measures the distance from the laser irradiation unit 301 to the wafer We held on the chuck table 307. The control unit 4 also detects the presence or absence of a step on the wafer ring structure W by measuring the distance from the distance measuring sensor 304 to the upper or lower surface of the wafer ring structure W. This allows the distance measuring sensor 304, which measures the distance from the laser irradiation unit 301 to the wafer We held on the chuck table 307, to be used to detect a step on the wafer ring structure W, eliminating the need to provide a separate member for step detection.

[0094] (Modifications) The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above-mentioned embodiments, and includes all modifications (modifications) within the meaning and scope of the claims.

[0095] For example, in the above embodiment, the control unit detects the step between the ring frame and the sheet member on the ring frame using a distance measurement sensor (detector) to obtain the front and back sides of the wafer ring structure, but the present invention is not limited to this. In the present invention, the control unit may detect the step between the ring frame and the sheet member on the inner periphery of the ring frame using the detector to obtain the front and back sides of the wafer ring structure. Furthermore, the control unit may detect the step between the sheet member and the wafer using the detector to obtain the front and back sides of the wafer ring structure.

[0096] In the above embodiment, an example of a configuration in which the distance measuring sensor (detector) is disposed above the wafer ring structure is shown, but the present invention is not limited to this. In the present invention, the detector may be disposed below the wafer ring structure and detect a step from below.

[0097] In the above embodiment, an example of a configuration in which a step in the wafer ring structure is detected by a distance measuring sensor that measures distance has been shown, but the present invention is not limited to this. In the present invention, a step in the wafer ring structure may be detected based on a captured image. In other words, the detection unit that detects the step may include a camera.

[0098] In the above embodiment, an example of a configuration in which steps in the wafer ring structure are detected by a distance measuring sensor that measures the distance to the wafer for laser dicing processing has been shown, but the present invention is not limited to this. In the present invention, steps in the wafer ring structure may be detected by providing a sensor that measures distance or a sensor that detects the surface shape, separate from the distance measuring sensor that measures the distance to the wafer for laser dicing processing.

[0099] In the above embodiment, an example of a configuration in which two transfer head units for transferring the wafer ring structure are provided is shown, but the present invention is not limited to this. In the present invention, one transfer head unit for transferring the wafer ring structure may be provided, or three or more transfer head units may be provided.

[0100] In the above embodiment, the laser irradiation unit is fixed in position in the horizontal direction, but the present invention is not limited to this. In the present invention, the laser irradiation unit may be movable in the horizontal direction.

[0101] In the above embodiment, for convenience of explanation, the control processing of the control unit is explained using a flow-driven flowchart in which processing is performed sequentially according to a processing flow, but the present invention is not limited to this. In the present invention, the control processing of the control unit may be performed by event-driven processing in which processing is performed on an event-by-event basis. In this case, the control processing may be performed completely event-driven, or may be performed in a combination of event-driven and flow-driven processing.

[0102] 4 Control unit 100 Laser dicing device 100a Housing 100b Door 241 Reversal unit 301 Laser irradiation unit 304 Distance measurement sensor (detection unit) 307 Chuck table unit (wafer holding unit) 309 High-magnification imaging unit (imaging unit) 431 Processing condition data W Wafer ring structure We Wafer Wf Ring frame Wt Sheet member

Claims

1. A laser dicing device comprising: a wafer holding unit that holds a wafer ring structure including a wafer, a sheet member to which the wafer is attached, and a ring frame that supports the sheet member; a laser irradiation unit that dices the wafer by irradiating the wafer held by the wafer holding unit with a laser; a detection unit that detects steps on the top or bottom surface of the wafer ring structure held by the wafer holding unit; and a control unit that obtains the orientation of the front and back of the wafer ring structure based on the presence or absence of steps on the top or bottom surface of the wafer ring structure detected by the detection unit.

2. The laser dicing device of claim 1, wherein the detection unit is configured to detect a step between the ring frame and the sheet member on the ring frame of the wafer ring structure, and the control unit obtains the front and back orientation of the wafer ring structure based on the presence or absence of a step between the ring frame and the sheet member on the ring frame detected by the detection unit.

3. The laser dicing device of claim 1, wherein the detection unit detects steps on the top or bottom surface of the wafer ring structure at multiple locations, and the control unit obtains the orientation of the front and back of the wafer ring structure based on the multiple detection results detected by the detection unit.

4. The laser dicing device of claim 1, wherein the control unit acquires processing condition data for the wafer and determines whether the front and back orientation of the wafer ring structure acquired based on the detection results by the detection unit is the same as the front and back orientation of the wafer ring structure based on the processing condition data.

5. The laser dicing device described in claim 4, wherein the control unit controls the display unit to display and notify when the front and back orientation of the wafer ring structure obtained based on the detection result by the detection unit differs from the front and back orientation of the wafer ring structure based on the processing condition data.

6. The laser dicing device of claim 4, wherein the control unit controls the detection unit to detect the presence or absence of a step in another part of the wafer ring structure when the front and back orientation of the wafer ring structure obtained based on the detection results by the detection unit differs from the front and back orientation of the wafer ring structure based on the processing condition data.

7. A laser dicing device as described in claim 4, further comprising an inversion unit that inverts the front and back of the wafer ring structure, wherein the control unit controls the inversion unit to invert the front and back of the wafer ring structure when the front and back orientation of the wafer ring structure obtained based on the detection result by the detection unit differs from the front and back orientation of the wafer ring structure based on the processing condition data.

8. The laser dicing device described in claim 7, wherein the control unit again controls the detection unit to obtain the orientation of the front and back of the wafer ring structure based on the presence or absence of a step in the wafer ring structure after the inversion unit has inverted the front and back of the wafer ring structure.

9. The laser dicing device of claim 4, wherein, when the orientation of the front and back of the wafer ring structure obtained based on the detection result by the detection unit differs from the orientation of the front and back of the wafer ring structure based on the processing condition data, the control unit changes the processing condition data to match the orientation of the front and back of the wafer ring structure held by the wafer holding unit, and controls the laser irradiation unit to irradiate the wafer with a laser for dicing processing.

10. The laser dicing device of claim 1, further comprising an imaging unit that images an alignment mark provided on the wafer, wherein the control unit performs control to obtain the orientation of the front and back of the wafer ring structure based on the presence or absence of a step in the wafer ring structure when the alignment mark cannot be detected based on the imaging results by the imaging unit.

11. The laser dicing device described in claim 1, wherein the control unit performs control to obtain the front and back orientation of the wafer ring structure based on the presence or absence of a step in the wafer ring structure when the processing condition data for the wafer is switched.

12. The laser dicing device of claim 1, further comprising a housing that covers the wafer holding unit and the laser irradiation unit and has a door that opens to the inside, wherein the control unit performs control to obtain the orientation of the front and back of the wafer ring structure based on the presence or absence of a step in the wafer ring structure when the door of the housing is opened and an operator performs work.

13. A laser dicing device as described in claim 1, further comprising a distance measuring sensor that measures the distance from the laser irradiation unit to the wafer held by the wafer holding unit, wherein the detection unit includes the distance measuring sensor, and the control unit detects the presence or absence of a step in the wafer ring structure by measuring the distance to the top or bottom surface of the wafer ring structure using the distance measuring sensor.

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