JP2018085435A - Workpiece processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To check whether or not wax reaches the entire surface of a workpiece when the workpiece is fixed to a supporting substrate via a bonding agent.SOLUTION: A workpiece processing method is constituted of at least a supporting substrate sticking step of sticking a workpiece W to a supporting substrate 1 having an outer diameter equal to that of the workpiece W or larger via a bond agent 2 such that the workpiece W is caused to face the supporting substrate 1 and a processing step of holding a support substrate 1 side to which the workpiece W is stuck on a rotatable chuck table and processing the workpiece W by processing means. The supporting substrate 1 is formed of a material having transparency such that spreading of the bond agent 2 from a rear surface 1 b of the supporting substrate 1 to the workpiece W can be confirmed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a workpiece processing method in which a workpiece is fixed to a support substrate for processing.

  During processing such as back grinding of workpieces, tape is usually attached to the surface where the workpiece is held, but if the workpiece is chamfered, the periphery of the workpiece thinned by grinding will be removed. There is also a possibility that a knife or edge is formed and cracks or cracks occur during subsequent processing. Therefore, a method is also employed in which a workpiece is attached to a support substrate made of a rigid body with a bonding agent such as wax, and the workpiece is processed in a state of being fixed to the support substrate via the bond agent (for example, Patent Document 1). reference). In addition, even for workpieces that have not been thinned, for those that have warping, the warpage is corrected by sticking to the support substrate via a bonding agent, and processing is performed in a state of being fixed to the support substrate. Yes.

JP2013-102080A

  However, when there is a large warp on the workpiece, unevenness may occur in the application state of the bond agent, and the entire surface of the workpiece may not be fixed. If machining of the workpiece is started in such a state, the workpiece holding state becomes unstable, and machining is hindered. Therefore, it is necessary to confirm whether or not the entire surface of the workpiece is fixed by the bond agent before starting the machining of the workpiece, but there is a problem that there is no method for confirming this in the present situation.

  The present invention has been considered in view of such problems, and when fixing a work to a support substrate via a bonding agent such as wax, it is possible to confirm whether or not the wax has spread over the entire surface of the work. This is the issue.

  The present invention is a workpiece processing method, wherein a workpiece is faced to a support substrate having an outer diameter equal to or larger than that of the workpiece, and the workpiece is bonded to the support substrate via a bonding agent. The supporting substrate includes at least a bonding step and a processing step of processing the workpiece by processing means while holding the supporting substrate side to which the workpiece is bonded to a rotatable chuck table, and the supporting substrate is the supporting substrate. It is formed by the raw material which has transparency which can confirm the spreading | diffusion from the back surface of this bond agent to this workpiece | work.

  The present invention uses, as a support substrate for supporting a workpiece via a bond agent, a material having transparency that can confirm the spread of the bond agent from the back surface of the support substrate to the workpiece, so that the bond agent from the support substrate side is used. It can be confirmed whether or not there is no unevenness in the coating state. Therefore, it is possible to prevent a processing defect caused by processing a workpiece whose entire surface is not fixed to the support substrate and moving the workpiece during processing.

It is a perspective view which shows an example of a workpiece | work. It is a perspective view which shows an example of sticking of the workpiece | work with respect to a support substrate. It is a front view which shows the state by which the surface of the workpiece | work which is correct | amended if there is no curvature is stuck to the surface of the support substrate through the bond agent. It is the bottom view which looked at the state by which the surface of the workpiece | work which is correct | amended or not warped is stuck to the surface of the support substrate through the bond agent from the back surface side of the support substrate. It is a front view which shows the state by which the surface of the workpiece | work where curvature is not corrected is stuck on the surface of the support substrate through the bond agent. It is the bottom view which looked at the state by which the surface of the workpiece | work where the curvature was not corrected is stuck on the surface of the support substrate through the bond agent from the back surface side of the support substrate. It is a front view which shows the state which grinds the back surface of the workpiece | work in which there is no curvature or is correct | amended. It is a perspective view which shows another example of sticking of the workpiece | work with respect to a support substrate. It is a front view which shows the state by which the back surface of the workpiece | work which is correct | amended if there is no curvature is stuck to the surface of the support substrate through the bond agent. It is a front view which shows the state which cuts the workpiece | work in which there is no curvature and is correct | amended.

  A wafer W shown in FIG. 1 is a kind of workpiece to which the present invention is applied, and a device D is formed on a surface Wa in a rectangular region defined by division lines L formed vertically and horizontally. In the following, regarding the method for processing the wafer W, a method for grinding the back surface Wb of the wafer W as a first embodiment and a method for dividing the wafer W along the division line L will be described as a second embodiment. .

1 1st Embodiment (1) Support substrate sticking process First, before grinding the back surface Wb of the wafer W, as shown in FIG. 2, the support substrate 1 for protecting the device D on the surface Wa is stuck. . In adhering the support substrate 1 to the surface Wa of the wafer W, first, the bond agent 2 is applied to the surface 1a which is the surface facing the surface Wa of the wafer W of the support substrate 1. Of the surface 1 a of the support substrate 1, the region where the bonding agent 2 is applied preferably has the same size as the entire surface Wa of the wafer W, but the region where the bonding agent 2 is applied is smaller than the surface Wa. Even so, when the surface Wa of the wafer W is pressed against the bond agent 2, the amount of the bond agent 2 applied may be adjusted so that the bond agent 2 spreads over a larger area than the surface Wa.

  As the bonding agent 2, acrylic resin, wax, polyimide resin or the like is used. On the other hand, the support substrate 1 is formed of a transparent or translucent material such as sapphire or glass. The support substrate 1 has an outer diameter equal to or larger than that of the wafer W. Here, the equivalent to the wafer W is not only when the outer diameter of the wafer W completely coincides with the outer diameter of the wafer W, but when the periphery of the wafer W is chamfered, for example, the outer diameter is reduced by chamfering. The case where the part and the outer diameter of the support substrate 1 coincide is also included.

  As shown in FIG. 2, the surface Wa of the wafer W is made to face the bond agent 2, and the surface Wa is pressed against the bond agent 2, so that the surface Wa and the surface 1 a of the support substrate 1 are attached via the bond agent 2. . As shown in FIG. 3, when the wafer W is not warped, or when the warpage of the wafer W is corrected and adhered to the support substrate 1, the distance between the surface Wa of the wafer W and the surface 1 a of the support substrate 1. The bonding agent 2 intervenes in the gap, and the entire surface Wa of the wafer W is adhered to the surface 1 a of the support substrate 1. Since the support substrate 1 is transparent or translucent and is formed of a material that can confirm the spread of the bonding agent 2 to the wafer W when viewed from the back surface 1b side of the support substrate 1, as shown in FIG. It is visually recognized that the agent 2 is not uneven.

  On the other hand, if the warp is large as in the wafer W1 shown in FIG. 5, the warp is not corrected even if the surface W1a of the wafer W1 is pressed against the bond agent 2, and a part of the bond agent 2 together with the wafer W1 is caused by the stress of the wafer W1. Be raised. Accordingly, when viewed from the back surface 1b side of the support substrate 1, as shown in FIG. 6, there is a non-adhered portion 3 where the bond agent 2 is not attached to the surface 1a of the support substrate 1, and the bond agent 2 is uneven. Looks like it happens. Therefore, in this case, it can be determined that the bonding agent 2 does not spread over the entire surface Wa of the wafer W and the wafer W is not completely fixed to the surface 1a of the support substrate 1.

  Confirmation of the spread of the bonding agent 2 from the support substrate 1 side performed as described above may be performed by an operator visually, or imaging with a camera is performed from the back surface 1b side of the support substrate 1 and the acquired image information is processed. You may carry out by image processing. In the case of image processing, the camera and the image processing apparatus may be provided in a sticking apparatus that sticks the wafer W to the support substrate 1 or may be provided in a grinding apparatus 4 used in a subsequent processing step. . In the image processing in this case, since the color information of the pixels of the non-sticking portion 3 varies, for example, there is a difference of a predetermined value or more between the maximum value and the minimum value of the pixel values of a certain range of pixels. In this case, it can be determined that the non-sticking portion exists.

  If it is determined that the entire surface Wa of the wafer W is adhered to the surface 1a of the support substrate 1, the process proceeds to the following processing steps. On the other hand, if it is determined that the entire surface Wa of the wafer W is not adhered to the surface 1a of the support substrate 1, this process is repeated or if the warpage of the wafer W cannot be corrected, the wafer W is excluded from the processing target.

(2) Processing step In the supporting substrate sticking step, when it is confirmed that the bonding agent 2 is interposed between the surface Wa of the wafer W and the supporting substrate 1 without any gap and there is no non-sticking portion, The wafer supported on the support substrate 1 via the agent 2 is conveyed to the grinding device 4 shown in FIG. First, after aligning the center of the wafer W and the center of the chuck table 40 with the rotatable chuck table 40 of the grinding device 4, the support substrate 1 side is held on the holding surface of the chuck table 40. 400. The wafer W is held on the chuck table 40 by applying a suction force to the holding surface 400 of the chuck table 40. At this time, the back surface Wb of the wafer W is exposed upward.

  Thus, the back surface Wb of the wafer W held on the chuck table 40 is ground by the grinding means 41. The grinding means 41 is configured such that a mount 43 is connected to a lower end of a rotating shaft 42 having a substantially vertical axis, and a grinding wheel 44 is attached to the mount 43. The grinding wheel 44 includes a base 440 fixed to the mount 43 and a plurality of grinding wheels 441 fixed in an annular shape to the lower surface of the base 440. The grinding means 41 is sent by the grinding feed means 45 in a direction approaching or separating from the holding surface 400.

  In the grinding means 41, a motor (not shown) rotates the rotating shaft 42 in the direction of the arrow 46 to rotate the grinding wheel 44 in the same direction. Then, the chuck table 40 is rotated in the direction of the arrow 47, and the grinding feed means 45 is ground and fed in a direction to bring the grinding means 41 closer to the wafer W, and the rotating grinding wheel 441 contacts the back surface Wb of the rotating wafer W. And grind. Then, the grinding feed is continued, and when the wafer W is formed to a predetermined thickness, the grinding feed means 45 separates the grinding means 41 from the wafer W, and the grinding is finished.

  Since it is confirmed in advance that the wafer W is adhered to the support substrate 1 without unevenness of the bonding agent 2 in the support substrate attaching step, the rotating grinding wheel 441 is rotated on the back surface Wb of the wafer W in the processing step. By contacting, it is possible to prevent the wafer W from moving when a horizontal force is applied to the wafer W. Therefore, the wafer W can be formed to a predetermined thickness without causing processing defects.

2 Second Embodiment (1) Support Substrate Adhering Step First, before cutting the wafer W, the support substrate 1 is attached to the back surface Wb of the wafer W shown in FIG. In attaching the support substrate 1 to the back surface Wb of the wafer W, first, the bonding agent 2 is applied to the front surface 1a of the support substrate 1 which is the surface facing the back surface Wb of the wafer W. Of the surface 1 a of the support substrate 1, the region where the bond agent 2 is applied preferably has the same size as the entire back surface Wb of the wafer W, but the region where the bond agent 2 is applied is smaller than the back surface Wb. Even so, when the back surface Wb of the wafer W is pressed against the bond agent 2, the coating amount of the bond agent 2 may be adjusted so that the bond agent 2 spreads over a larger area than the back surface Wb. As the bonding agent 2, acrylic resin, wax, polyimide resin or the like can be used. On the other hand, the support substrate 1 is formed of a transparent or translucent material such as sapphire or glass.

  Then, the back surface Wb of the wafer W is made to face the bond agent 2, and the back surface Wb is pressed against the bond agent 2, so that the back surface Wb and the surface 1 a of the support substrate 1 are attached. As shown in FIG. 9, when the wafer W is not warped or when the warpage of the wafer W is corrected and adhered to the support substrate 1, a bonding agent is provided between the back surface Wb of the wafer W and the support substrate 1. Since 2 is interposed without a gap, when viewed from the back surface 1b side of the support substrate 1, it is visually recognized that the bond agent 2 is not uneven, as shown in FIG.

  On the other hand, in the same manner as shown in FIG. 5, when there is a non-sticking portion where the bonding agent 2 is not stuck between the back surface Wb of the wafer W and the front surface 1 a of the support substrate 1, Is determined not to be fixed to the surface 1 a of the support substrate 1.

  Confirmation of the spread of the bonding agent 2 from the support substrate 1 side performed as described above may be performed by an operator visually, or imaging with a camera is performed from the back surface 1b side of the support substrate 1 and the acquired image information is processed. You may carry out by image processing. In the case of image processing, the camera and the image processing apparatus may be provided in a sticking apparatus that sticks the wafer W to the support substrate 1 or may be provided in a cutting device 5 used in a subsequent processing step. . In the image processing in this case, since there is a variation in the color information of the pixels of the non-sticking part, for example, there is a difference of a predetermined value or more between the maximum value and the minimum value of the pixel values of a certain range of pixels It can be determined that there is a non-sticking portion.

  If it is determined that the entire surface of the back surface Wb of the wafer W is adhered to the front surface 1a of the support substrate 1, the process proceeds to the following processing steps. On the other hand, if it is determined that the entire back surface Wb of the wafer W is not adhered to the front surface 1a of the support substrate 1, the process is repeated or if the warpage of the wafer W cannot be corrected, the wafer. W is excluded from the processing target.

(2) Processing step In the supporting substrate sticking step, when it is confirmed that the bonding agent 2 is interposed between the back surface Wb of the wafer W and the supporting substrate 1 without any gap and no non-sticking portion exists, The wafer supported on the support substrate 1 via the agent 2 is conveyed to the cutting device 5 shown in FIG. First, as shown in FIG. 10, the center of the wafer W and the center of the chuck table 50 are aligned with the chuck table 50 that is rotatable and movable in the X-axis direction of the cutting device 5. Above, the support substrate 1 side is placed on the holding surface 500 of the chuck table 50. Then, the wafer W is held on the chuck table 50 by applying a suction force to the holding surface 500. At this time, the surface Wa of the wafer W is exposed upward.

  Thus, the wafer W held on the chuck table 50 is cut by the cutting means 51 along the scheduled division line L shown in FIG. The cutting means 51 is configured by attaching a cutting blade 53 to the tip of a rotary shaft 52 having an axis in the Y-axis direction perpendicular to the horizontal direction with respect to the X-axis direction. Is provided with an alignment means 54 for picking up and detecting the division line L. The cutting means 51 and the alignment means 54 are configured to be driven in the Y-axis direction by the index feeding means 55 and to be driven in the Z-axis direction by the cutting feed means 56.

  Before the cutting by the cutting means 51, the chuck table 50 moves in the X-axis direction, whereby the wafer W is positioned below the alignment means 54, and the alignment means 54 images the surface Wa of the wafer W. Then, the alignment means 54 detects the division line L to be cut, and the detected division line L and the cutting blade 53 are aligned in the Y-axis direction.

  The chuck table 50 is cut and fed in the direction of the arrow 57 from the state where the alignment has been performed, and the cutting blade 53 is rotated in the direction of the arrow 58 by rotating the rotating shaft 52 by a motor (not shown). Thus, the cutting means 51 is cut and fed in the direction approaching the wafer W by the cutting feed means 56, whereby the cutting blade 53 is cut into the division line L. At this time, the cutting feed means 56 controls the position of the cutting means 51 so that the lower end of the cutting blade 53 reaches the bonding agent 2 but does not reach the surface 1 a of the support substrate 1. Then, the division line L is cut without damaging the support substrate 1.

  After one division line L is cut, the chuck table 50 is moved in the −X direction to return to the original position. Then, after the cutting means 51 is indexed and fed in the Y-axis direction by the interval between the adjacent division lines L, the chuck table 50 is moved in the direction of the arrow 57, and the next division line L is determined by the same method. To cut. In this way, after cutting all the planned division lines L arranged in the same direction, the chuck table 50 is rotated by 90 degrees, and all the planned division lines L orthogonal to the cut partial division lines L are cut by the same method. Also cut about.

  When all the division lines L are cut vertically and horizontally in this way, the wafer W is divided into chips for each device D. Each chip is maintained in a state of being bonded to the support substrate 1 by the bonding agent 2.

  In the present embodiment, the cutting blade 53 is cut to the bond agent 2 to completely cut the division line L. However, the cutting means 51 is kept until the lower end of the cutting blade 53 is located inside the wafer W. By lowering, a groove that does not penetrate to the back surface Wb of the wafer W may be formed. In this case, the back surface Wb side of the wafer W is removed from the support substrate 1 by melting the bond agent 2 or the like, and the surface Wa of the wafer W is bonded to the front surface Wa of the wafer W via the bond agent as shown in the first embodiment. After attaching the front surface 1a, the back surface Wb is ground or the like, and is divided into chips for each device D.

W, W1: Wafer Wa: Front surface L: Planned division line D: Device Wb: Back surface 1: Support substrate 1a: Front surface 1b: Back surface 2: Bonding agent 3: Non-sticking part 4: Grinding device 40: Chuck table 400: Holding Surface 41: Grinding means 42: Rotating shaft 43: Mount 44: Grinding wheel 440: Base 441: Grinding wheel 45: Grinding feed means 5: Cutting device 50: Chuck table 500: Holding surface 51: Cutting means 52: Rotating shaft 53 : Cutting blade 54: Alignment means 55: Index feeding means 56: Cutting feed means

Claims (1)

A method for machining a workpiece,
A support substrate pasting step of facing the work to a support substrate having an outer diameter equal to or larger than the work and pasting the work to the support substrate via a bonding agent;
The supporting substrate side to which the workpiece is stuck is held on a rotatable chuck table and the workpiece is processed by a processing means, and at least the processing step is configured.
The workpiece processing method, wherein the support substrate is formed of a material having transparency that allows the bonding agent to be confirmed to spread from the back surface of the support substrate to the workpiece.

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