JP2017063150A - Workpiece processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a workpiece processing method by which a chamfering portion can be readily removed without causing clogging in a cutting blade.SOLUTION: In a workpiece processing method, a workpiece (11) having a functional layer (15) forming a part of a device (17) formed on the side of a surface (13a) of a substrate (13) is processed, provided that the substrate has a chamfer portion (13c) where a peripheral edge is chamfered. The method comprises: a support member-fixing step for fixing a support member (21) to the surface of the workpiece on the side of the functional layer through an adhesive (23); a peripheral edge-cutting step for operating a rotating cutting blade to cut in the workpiece to a depth not reaching the functional layer from a rear face (11b) of the workpiece along the peripheral edge, thereby partially removing the chamfer portion and leaving a residual uncut portion (13d) along the peripheral edge on the surface side of the substrate; a dry etching step for removing the residual uncut portion by dry etching, thereby exposing a part of the functional layer, which the residual uncut portion overlies, on the side of the rear face of the workpiece; and a thinning step for thinning the workpiece by grinding the substrate from the rear face side thereof.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for processing a workpiece in which a functional layer to be a part of a device is formed on a substrate having a chamfered portion whose outer peripheral edge is chamfered.

  In recent years, in order to realize a small and light device chip, there are increasing opportunities to thinly process a wafer (substrate) made of a semiconductor material such as silicon. For example, a wafer in which devices such as ICs are respectively formed in a plurality of regions partitioned by a division line (street) on the front surface is thinned by grinding the back surface side. The wafer after thinning is divided into a plurality of device chips corresponding to each device along the division line.

  The outer peripheral edge of a wafer used for manufacturing such a device chip is chamfered to prevent chipping, cracking, and the like during conveyance. However, when the chamfered wafer is thinned by grinding, the outer peripheral edge of the wafer is thin and sharp like a knife edge, and on the contrary, chipping, cracking, etc. are likely to occur.

  Therefore, a processing method has been proposed in which a chamfered portion (chamfered portion) of the wafer is cut and removed before thinning by grinding (see, for example, Patent Document 1). In this processing method, a cutting blade is cut from the wafer surface side to the outer peripheral edge before grinding to cut and remove the chamfered portion, thereby preventing the outer peripheral edge from being sharply sharp like a knife edge. Yes.

  By the way, when the cutting blade is cut from the front surface side of the wafer and the chamfered portion is cut and removed as described above, the cutting waste generated by the cutting easily adheres to the device on the front surface side. Therefore, in this case, the wafer has to be carefully cleaned in order to remove the attached cutting waste, and the cost required for cleaning the wafer has increased.

  On the other hand, a processing method is also known in which a cutting blade is cut from the back surface side of the wafer to the outer peripheral edge to cut and remove all the chamfered portions. In this processing method, since the supporting member is attached to the front surface side of the wafer and the outer peripheral edge is cut from the back surface side, the cutting waste does not adhere to the device. Further, in this processing method, after removing the chamfered portion, the back surface side of the wafer can be ground as it is without replacing the supporting member, so that the process is also simplified.

JP 2014-33152 A JP 2010-165802 A

  In the above-described processing method in which the cutting blade is cut from the back surface side of the wafer, in order to remove all the chamfered portions, it is necessary to cut the cutting blade to at least an adhesive that adheres the support member to the surface of the wafer. is there. However, since this adhesive is usually formed of a soft material such as resin, if the cutting blade is cut into the adhesive, the cutting blade is clogged with the adhesive, causing problems such as uneven wear. Is likely to occur.

  In order to prevent clogging of the cutting blade, for example, the cutting blade may be cut accurately at the interface between the wafer surface and the adhesive and the cutting blade may not be cut into the adhesive. On the other hand, when the wafer and the support member are bonded together, the wafer is often inclined with respect to the support member, and the height of the interface is usually not constant. For this reason, in order to accurately adjust the height of the cutting blade with respect to the interface, complicated processes and special equipment are required.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a processing method for a workpiece that can easily remove a chamfered portion without causing clogging of a cutting blade. It is.

  According to the present invention, there is provided a workpiece processing method for processing a workpiece in which a functional layer serving as a part of a device is formed on a surface side of a substrate having a chamfered portion whose outer peripheral edge is chamfered. A supporting member fixing step for fixing the supporting member to the surface side of the object having the functional layer via an adhesive, and a cutting blade that rotates after the supporting member fixing step is performed from the back surface side of the workpiece to the outer periphery. An outer periphery cutting step that cuts to a depth that does not reach the functional layer along the surface, removes a portion of the chamfered portion, and leaves an uncut portion along the outer periphery on the surface side of the substrate, and the outer periphery cutting After performing the step, after performing the dry etching step of removing the uncut portion by dry etching and exposing the functional layer overlapping the uncut portion on the back side of the workpiece, and after performing the dry etching step, Base Method for processing a workpiece, characterized in that it comprises a thinning step, a thinning of the workpiece by grinding the back surface side is provided.

  In the present invention, after carrying out the thinning step, the method further comprises a mark recess forming step of forming a recess serving as a mark indicating the crystal orientation of the substrate by processing the outer peripheral portion on the back surface side of the substrate by local dry etching. It is preferable.

  In the workpiece processing method according to the present invention, the cutting blade is cut from the back surface side of the workpiece to a depth that does not reach the functional layer along the outer peripheral edge, and after removing a part of the chamfered portion, The uncut portion remaining on the front side is removed by dry etching, and the functional layer overlapping the uncut portion is exposed on the back side of the workpiece, so the chamfered portion is removed without cutting the cutting blade into the adhesive. it can. Therefore, the cutting blade is not clogged with the adhesive.

  Further, in the processing method of the workpiece according to the present invention, the uncut portion remaining after cutting the cutting blade is removed by dry etching, so when cutting the cutting blade, the surface of the workpiece There is no need to precisely adjust the height of the cutting blade to the interface with the adhesive. That is, complicated processes and special equipment are not required. Thus, according to the processing method of the workpiece which concerns on this invention, a chamfer part can be easily removed, without generating clogging in a cutting blade.

FIG. 1A is a perspective view schematically showing a support member fixing step, and FIG. 1B is a perspective view schematically showing a workpiece to which the support member is fixed. C) is a cross-sectional view schematically showing a workpiece to which a support member is fixed. It is a partial cross section side view showing typically a resist film formation step. FIG. 3A is a partial cross-sectional side view schematically showing the outer periphery cutting step, and FIG. 3B is a cross-sectional view schematically showing the state of the workpiece after the outer periphery cutting step. It is. It is a schematic diagram which shows typically a dry etching step. It is sectional drawing which shows typically the state of the to-be-processed object after a dry etching step. 6A is a partial cross-sectional side view schematically showing the thinning step, and FIG. 6B is a cross-sectional view schematically showing the state of the workpiece after the thinning step. . FIG. 7A is a plan view schematically showing the shape of the resist film formed in the mark recess forming step, and FIG. 7B schematically shows the state of the workpiece after the mark recess forming step. FIG. It is a figure which shows typically the structural example of the dry etching apparatus used at the mark recessed part formation step which concerns on a modification. It is a disassembled perspective view which shows typically the structural example of the dry etching apparatus used at the mark recessed part formation step which concerns on a modification. It is a partial cross section side view which shows typically a mode that a to-be-processed object is processed with the plasma supplied from a nozzle unit. FIG. 11A is a plan view schematically showing the state of the workpiece after the mark recess forming step according to the modification, and FIG. 11B is after the mark recess forming step according to the modification. It is sectional drawing which shows the state of the to-be-processed object typically.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The workpiece processing method according to the present embodiment is a workpiece processing method for processing a workpiece in which a functional layer is formed on the surface side of a wafer (substrate) having a chamfered portion with a chamfered outer periphery. The supporting member fixing step (see FIGS. 1A, 1B, and 1C), the resist film forming step (see FIG. 2), the outer peripheral edge cutting step (FIG. 3A and FIG. 3 (B)), dry etching step (see FIGS. 4 and 5), thinning step (see FIGS. 6A and 6B), and recess forming step (FIGS. 7A and 7). (See (B)).

  In the support member fixing step, the support member is fixed to the surface side of the workpiece having the functional layer via an adhesive. In the resist film forming step, the back side of the workpiece is covered with a resist film. In the outer peripheral cutting step, the cutting blade is cut from the back surface side of the workpiece to a depth that does not reach the functional layer along the outer peripheral edge, and a part of the back surface side of the chamfered portion is removed and an uncut portion on the front surface side. To remain.

  In the dry etching step, the uncut portion is removed by dry etching, and the functional layer overlapping the uncut portion is exposed on the back side. In the thinning step, the work piece is thinned by grinding the back side of the wafer. In the mark recess forming step, the outer peripheral portion on the back surface side of the wafer is processed by local dry etching to form a recess serving as a mark indicating the crystal orientation. Hereinafter, the processing method of the workpiece which concerns on this embodiment is explained in full detail.

  In the workpiece processing method according to the embodiment, first, a support member fixing step of fixing the support member to the workpiece is performed. FIG. 1A is a perspective view schematically showing a support member fixing step, and FIG. 1B is a perspective view schematically showing a workpiece to which the support member is fixed. C) is a cross-sectional view schematically showing a workpiece to which a support member is fixed.

  As shown in FIGS. 1 (A), 1 (B), and 1 (C), the workpiece 11 processed in this embodiment includes a wafer (substrate) 13 serving as a base material, and a wafer 13. And a functional layer 15 formed on the entire surface 13a side. For example, the wafer 13 is formed in a disk shape from a semiconductor material such as silicon, and its outer peripheral edge is chamfered.

  On the other hand, the functional layer 15 includes a metal film serving as a wiring, an insulating film that insulates the wiring, a semiconductor film, and the like. In the present embodiment, the exposed surface of the functional layer 15 is referred to as the front surface 11 a of the workpiece 11, and the back surface 13 b of the wafer 13 is referred to as the back surface 11 b of the workpiece 11. Further, the outer peripheral edge of the chamfered wafer 13 is referred to as a chamfered portion 13c.

  The surface 11a side of the workpiece 11 is divided into a plurality of regions by a plurality of scheduled division lines (streets) intersecting each other, and devices 17 such as ICs and LSIs are formed in each region. Each device 17 includes the functional layer 15 described above as a component. That is, the functional layer 15 becomes a part of the device.

  In the support member fixing step, the support member 21 is fixed to the surface 11a side of the workpiece 11 described above. The support member 21 is, for example, a film (adhesive tape) that is substantially the same shape as the workpiece 11, a resin substrate, a wafer of the same or different type from the wafer 13, and the like. An adhesive layer (adhesive) 23 made of an adhesive such as a resin is provided on the first surface 21 a of the support member 21.

  Therefore, as shown in FIG. 1 (A), by bringing the adhesive layer 23 provided on the support member 21 into contact with the surface 11a of the workpiece 11, as shown in FIG. 1 (B) and FIG. 1 (C). In addition, the support member 21 can be attached and fixed to the workpiece 11. By fixing the support member 21 to the surface 11a side of the wafer 11, for example, the workpiece 11 processed thinly in a subsequent thinning step can be easily handled.

  After the supporting member fixing step, a resist film forming step for covering the back surface 11b side of the workpiece 11 with a resist film is performed. FIG. 2 is a partial cross-sectional side view schematically showing the resist film forming step. The resist film formation step according to the present embodiment is performed by, for example, the spin coater 2 shown in FIG.

  The spin coating device 2 includes a chuck table 4 for holding the workpiece 11. The chuck table 4 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis substantially parallel to the vertical direction. The upper surface of the chuck table 4 serves as a holding surface 4 a that sucks and holds the second surface 21 b of the support member 21 fixed to the workpiece 11.

  The holding surface 4 a is connected to a suction source (not shown) through a suction path (not shown) formed inside the chuck table 4. The workpiece 11 can be held by the chuck table 4 by applying the negative pressure of the suction source to the holding surface 4a. Above the chuck table 4, a nozzle 6 for dropping a resist material 31 resistant to dry etching (typically plasma etching) described later is disposed.

  In the resist film forming step, first, the second surface 21b of the support member 21 fixed to the workpiece 11 is brought into contact with the holding surface 4a of the chuck table 4 to apply a negative pressure of the suction source. Thereby, the workpiece 11 is held by the chuck table 4 with the back surface 11b side exposed upward.

  Next, the chuck table 4 is rotated and the resist material 31 is dropped from the nozzle 6. Thereby, the resist material 31 can be applied to the back surface 11b side of the workpiece 11 (the back surface 13b of the wafer 13). Thereafter, the applied resist material 31 is cured to complete the resist film 33 that covers the back surface 11b side of the workpiece 11. The resist film 33 also has water resistance (water resistance).

  After the resist film forming step, a cutting blade is cut along the outer peripheral edge of the workpiece 11 to remove the back surface 13b side of the chamfered portion 13c and to leave an uncut portion on the front surface 13a side. Perform the cutting step. FIG. 3A is a partial cross-sectional side view schematically showing the outer periphery cutting step, and FIG. 3B is a cross section schematically showing the state of the workpiece 11 after the outer periphery cutting step. FIG.

  The outer peripheral edge cutting step according to the present embodiment is performed by, for example, a cutting device 22 shown in FIG. The cutting device 22 includes a chuck table 24 for holding the workpiece 11. The chuck table 24 is connected to a rotation drive source (not shown) including a motor and the like, and rotates around a rotation axis substantially parallel to the vertical direction. A moving mechanism (not shown) is provided below the chuck table 24, and the chuck table 24 is moved in the horizontal direction by the moving mechanism.

  The upper surface of the chuck table 24 is a holding surface 24 a that sucks and holds the second surface 21 b of the support member 21 fixed to the workpiece 11. The holding surface 24 a is connected to a suction source (not shown) through a suction path (not shown) formed inside the chuck table 24. The workpiece 11 can be held by the chuck table 24 by applying the negative pressure of the suction source to the holding surface 24a.

  A cutting unit 26 for cutting the workpiece 11 is disposed above the chuck table 24. The cutting unit 26 includes a spindle housing (not shown) supported by an elevating mechanism (not shown). A spindle 28 connected to a rotation drive source (not shown) including a motor and the like is accommodated in the spindle housing.

  The spindle 28 is rotated around a rotation axis substantially parallel to the horizontal direction by a rotational force transmitted from a rotational drive source, and is lifted and lowered together with the spindle housing by a lifting mechanism. An annular cutting blade 30 is attached to one end of the spindle 28 exposed to the outside of the spindle housing.

  In the outer peripheral cutting step, first, the second surface 21b of the support member 21 fixed to the workpiece 11 is brought into contact with the holding surface 24a of the chuck table 24, and the negative pressure of the suction source is applied. Thereby, the workpiece 11 is held by the chuck table 24 with the back surface 11b side exposed upward.

  Next, the chuck table 24 and the cutting unit 26 are relatively moved to align the cutting blade 30 with the chamfered portion 13c of the workpiece 11 as shown in FIG. Thereafter, the rotated cutting blade 30 is lowered to a predetermined position and cut into the workpiece 13, and the chuck table 24 is rotated. That is, the cutting blade 30 is cut along the outer peripheral edge from the back surface 11 b side of the workpiece 11. At this time, the workpiece 11 is supplied with a cutting fluid that promotes the discharge of the cutting waste.

  The descending amount of the cutting blade 30 is adjusted in a range where the cutting blade 30 does not cut into the functional layer 15. As a result, as shown in FIG. 3B, the back surface 13b side of the chamfered portion 13 can be removed along the outer peripheral edge, and the uncut portion 13d can be left on the front surface 13a side.

  As shown in FIG. 3B, when the workpiece 11 is inclined with respect to the support member 21, the thickness of the uncut portion 13d is not constant, but the uncut portion 13d is Since it can be completely removed by a dry etching step, there is no problem. In addition, a part of the resist film 33 that overlaps the chamfered portion 13 is also removed by this outer peripheral cutting step.

  After the outer peripheral edge cutting step, a dry etching step is performed in which the uncut portion 13d is removed by dry etching and the functional layer 15 overlapping the uncut portion 13d is exposed to the back surface 11b side. FIG. 4 is a schematic view schematically showing the dry etching step, and FIG. 5 is a cross-sectional view schematically showing the state of the workpiece 11 after the dry etching step.

  The dry etching step of the present embodiment is performed by, for example, a dry etching apparatus (plasma etching apparatus) 102 shown in FIG. The dry etching apparatus 102 includes a vacuum chamber 106 in which a processing space 104 is formed. An opening 108 for carrying the workpiece 11 in and out is formed in the side wall 106 a of the vacuum chamber 106.

  A gate 110 that opens and closes the opening 108 is attached to the outside of the opening 108. An opening / closing mechanism 112 is provided below the gate 110, and the gate 110 moves up and down by the opening / closing mechanism 112. By moving the gate 110 downward by the opening / closing mechanism 112 and opening the opening 108, the workpiece 11 is carried into the processing space 104 of the vacuum chamber 106 through the opening 108, or the workpiece 11 is processed in the vacuum chamber 106. It can be carried out from the space 104.

  An exhaust port 114 is formed in the bottom wall 106 b of the vacuum chamber 106. The exhaust port 114 is connected to an exhaust device 116 such as a vacuum pump. In the processing space 104 of the vacuum chamber 106, a lower electrode 118 and an upper electrode 120 are disposed so as to face each other.

  The lower electrode 118 is made of a conductive material, and includes a disk-shaped holding part 122 and a columnar support part 124 extending downward from the center of the lower surface of the holding part 122. The support part 124 is inserted through an opening 126 formed in the bottom wall 106 b of the vacuum chamber 106.

  In the opening 126, an insulating bearing 128 is disposed between the bottom wall 106b and the support portion 124, and the vacuum chamber 106 and the lower electrode 118 are insulated. The lower electrode 118 is connected to the high frequency power supply 130 outside the vacuum chamber 106.

  A concave portion is formed on the upper surface of the holding portion 122, and a table 132 on which the workpiece 11 is placed is installed in the concave portion. The table 132 is provided with a suction path (not shown), and this suction path is connected to a suction source 136 through a suction path 134 formed inside the lower electrode 128.

  In addition, a cooling channel 138 is formed inside the holding unit 122. One end of the cooling flow path 138 is connected to the circulation device 142 through the refrigerant supply path 140 formed in the support portion 124, and the other end of the cooling flow path 138 is connected through the refrigerant discharge path 144 formed in the support section 124. It is connected to the circulation device 142. When the circulation device 142 is operated, the refrigerant flows in the order of the refrigerant supply path 140, the cooling flow path 138, and the refrigerant discharge path 144 to cool the lower electrode 118.

  The upper electrode 120 is made of a conductive material, and includes a disk-like gas ejection part 146 and a columnar support part 148 extending upward from the center of the upper surface of the gas ejection part 146. The support portion 148 is inserted through an opening 150 formed in the upper wall 106 c of the vacuum chamber 106.

  In the opening 150, an insulating bearing 152 is disposed between the upper wall 106c and the support portion 148, and the vacuum chamber 106 and the upper electrode 120 are insulated. The upper electrode 120 is connected to the high frequency power supply 130 outside the vacuum chamber 106. The upper end portion of the support portion 148 is connected to the support arm 158 of the lifting mechanism 156, and the upper electrode 120 moves up and down by the lifting mechanism 156.

  A plurality of gas ejection ports 160 are formed on the lower surface of the gas ejection portion 146. The gas outlet 160 is connected to a gas supply source 164 through a flow path 162 and the like. As a result, the etching source gas can be supplied to the processing space 104 in the vacuum chamber 106.

  In the dry etching step, first, the gate 110 is lowered by the opening / closing mechanism 112. Next, the workpiece 11 is carried into the processing space 104 of the vacuum chamber 106 through the opening 108 and placed on the table 132 of the lower electrode 118. Specifically, the second surface 21 b of the support member 21 fixed to the workpiece 11 is brought into contact with the table 132. Further, when the workpiece 11 is carried in, the upper electrode 120 is raised by the lifting mechanism 156 to secure a loading space for the workpiece 11.

  Thereafter, the negative pressure of the suction source 136 is applied to fix the workpiece 11 on the table 132. Further, the gate 110 is raised by the opening / closing mechanism 112 to seal the processing space 104. Further, the upper electrode 120 is lowered by the elevating mechanism 156 so that the lower electrode 118 and the upper electrode 120 have a predetermined positional relationship suitable for etching. Further, the exhaust device 116 is operated to make the processing space 104 vacuum (low pressure).

  In this state, when a predetermined high frequency power is supplied to the lower electrode 118 and the upper electrode 120 by the high frequency power supply 130 while supplying a raw material gas for etching from the gas supply source 164 at a predetermined flow rate, the lower electrode 118 and the upper electrode 120 are supplied. Plasma containing radicals and ions is generated between the two.

  As a result, as shown in FIG. 5, the uncut portion 13d of the wafer 13 not covered with the resist film 33 is removed by dry etching (plasma etching), and the functional layer 15 overlapping the uncut portion 13d is formed on the back surface 11b side. Exposed. Note that the etching source gas is appropriately selected according to the material of the workpiece 11 and the like. Specifically, it is desirable to select a source gas that increases the etching rate of the wafer 13 and decreases the etching rate of the functional layer 15. This facilitates the control of dry etching.

  After the dry etching step, a thinning step for grinding the back surface 13b side of the wafer 13 to thin the workpiece 11 is performed. FIG. 6A is a partial cross-sectional side view schematically showing the thinning step, and FIG. 6B is a cross-sectional view schematically showing the state of the workpiece 11 after the thinning step. is there. Note that it is desirable to remove the resist film 33 by a method such as ashing before performing this thinning step.

  The thinning step of the present embodiment is performed by, for example, a grinding device 42 shown in FIG. The grinding device 42 includes a chuck table 44 for holding the workpiece 11. The chuck table 44 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis substantially parallel to the vertical direction. A moving mechanism (not shown) is provided below the chuck table 44, and the chuck table 44 is moved in the horizontal direction by the moving mechanism.

  The upper surface of the chuck table 44 is a holding surface 44 a that sucks and holds the second surface 21 b of the support member 21 fixed to the workpiece 11. The holding surface 44 a is connected to a suction source (not shown) through a suction path (not shown) formed inside the chuck table 44. The workpiece 11 can be held by the chuck table 44 by applying the negative pressure of the suction source to the holding surface 44 a.

  A grinding unit 46 is disposed above the chuck table 44. The grinding unit 46 includes a spindle housing 48 supported by an elevating mechanism (not shown). A spindle housing 50 is accommodated in the spindle housing 48, and a disc-shaped mount 52 is fixed to the lower end portion of the spindle 50.

  A grinding wheel 54 having substantially the same diameter as the mount 52 is mounted on the lower surface of the mount 52. The grinding wheel 54 includes a wheel base 56 formed of a metal material such as stainless steel or aluminum. A plurality of grinding wheels 58 are arranged in an annular shape on the lower surface of the wheel base 56.

  A rotation drive source (not shown) such as a motor is connected to the upper end side (base end side) of the spindle 50. The grinding wheel 54 rotates around a rotation axis substantially parallel to the vertical direction by the rotational force transmitted from the rotational drive source.

  In the thinning step, first, the second surface 21b of the support member 21 fixed to the workpiece 11 is brought into contact with the holding surface 44a of the chuck table 44 to apply a negative pressure of the suction source. Thereby, the workpiece 11 is held on the chuck table 44 with the back surface 11b side exposed upward.

  Next, the chuck table 44 is moved below the grinding wheel 54. Then, as shown in FIG. 6A, the spindle table 48 and the grinding wheel 54 are rotated to lower the spindle housing 48 while supplying a grinding liquid such as pure water. The descending amount of the spindle housing 48 is adjusted so that the lower surface of the grinding wheel 58 is pressed against the back surface 13b of the wafer 13 (the back surface 11b of the workpiece 11). Thereby, the back surface 13b side of the wafer 13 can be ground and the workpiece 11 can be thinned.

  This thinning step is performed, for example, while measuring the thickness of the workpiece 11. As shown in FIG. 6B, when the workpiece 11 is thinned to the finished thickness, the thinning step ends. It should be noted that if a spectral interference type measuring device that uses light having a wavelength that passes through the workpiece 11 and is reflected by the adhesive layer 23 is used, the thickness (thickness) of the workpiece 11 held on the chuck table 44 is determined. Distribution etc.) can also be measured. Then, by adjusting the inclination or the like of the chuck table 44 according to the thickness (thickness distribution) of the workpiece 11, the workpiece 11 can be made to have a uniform thickness even when the thickness of the adhesive layer 23 is not uniform. It can be thinned.

  After the thinning step, a mark recess forming step is performed in which the outer peripheral portion on the back surface 13b side of the wafer 13 is processed by local dry etching to form a recess serving as a mark indicating the crystal orientation. FIG. 7A is a plan view schematically showing the shape of the resist film formed in the mark recess forming step, and FIG. 7B shows the state of the workpiece 11 after the mark recess forming step. It is sectional drawing shown typically.

  This mark recess forming step is performed in the same procedure as the resist film forming step and the dry etching step described above. Specifically, first, as illustrated in FIG. 7A, the back surface 11 b side of the workpiece 11 is covered with a resist film 35. However, here, the resist film 35 having a predetermined notch pattern 35a is formed so that the back surface 13b of the wafer 13 is exposed in a region (peripheral portion) in the vicinity of the outer peripheral edge where a concave portion to be a mark is formed.

  Thereafter, if the workpiece 11 is processed by dry etching, a recess 13e having a shape corresponding to the notch pattern 35a can be formed in the wafer 13. Thereby, even when a notch or the like indicating the crystal orientation of the wafer 13 is removed, the crystal orientation can be recognized based on the recess 13e. Note that it is desirable to remove the resist film 35 by a method such as ashing after the step of forming the mark recess.

  As described above, in the processing method of the workpiece according to the present embodiment, the cutting blade 30 is cut from the back surface 11b side of the workpiece 11 to the depth that does not reach the functional layer 15 along the outer peripheral edge. After removing a part of 13c, the uncut portion 13d remaining on the front surface 13a side of the wafer (substrate) 13 is removed by dry etching, and the functional layer 15 overlapping the uncut portion 13d is removed from the back surface 11b of the workpiece 11. Therefore, the chamfered portion 13 c can be removed without cutting the cutting blade 30 into the adhesive layer (adhesive) 23. Therefore, the cutting blade 30 is not clogged with the adhesive.

  Moreover, in the processing method of the workpiece which concerns on this embodiment, since the uncut part 13d which remains after cutting the cutting blade 30 is removed by dry etching, when cutting the cutting blade 30, it is processed. It is not necessary to precisely match the height of the cutting blade 30 with the interface between the surface 11a of the object 11 and the adhesive layer 23. That is, complicated processes and special equipment are not required. Thus, according to the processing method for the workpiece according to the present embodiment, the chamfered portion 13c can be easily removed without causing the cutting blade 30 to be clogged.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the above-described embodiment, the dry etching step is performed after the resist film forming step is performed. However, when the thickness reduction of the wafer 13 due to the dry etching does not cause a problem, the resist film forming step is performed. May be omitted.

  In the above embodiment, the resist film 35 having the notch pattern 35a corresponding to the recess 13e is formed in the mark recess forming step. However, the recess 13e can be formed without forming the resist film 35. .

  FIG. 8 is a diagram schematically showing a configuration example of a dry etching apparatus (plasma etching apparatus) used in the mark recess forming step according to the modification, and FIG. 9 is used in the mark recess forming step according to the modification. It is a disassembled perspective view which shows the structural example of a dry etching apparatus typically. For convenience of explanation, some of the components are omitted in FIG.

  As shown in FIGS. 8 and 9, a dry etching apparatus (plasma etching apparatus) 202 according to a modification includes a vacuum chamber 204 that forms a processing space. The vacuum chamber 204 includes a box-shaped main body 206 and a lid 208 that closes the upper portion of the main body 206. An opening 206 b for carrying the workpiece 11 in and out is formed in a part of the side wall 206 a of the main body 206.

  A gate 210 that closes the opening 206b is disposed outside the side wall 206a. An opening / closing unit 212 made of an air cylinder or the like is provided below the gate 210, and the gate 210 moves up and down by the opening / closing unit 212. If the gate 210 is moved downward by the opening / closing unit 212 to expose the opening 206b, the workpiece 11 can be carried into the processing space through the opening 206b, or the workpiece 11 can be carried out of the processing space.

  An exhaust pump 216 is connected to the bottom wall 206c of the main body 206 via a pipe 214 or the like. When processing the workpiece 11, the gate 210 is moved upward by the opening / closing unit 212 to close the opening 206 b, and then the processing space is exhausted and decompressed by the exhaust pump 216.

  A table base 218 for supporting the workpiece 11 is arranged in the processing space. The table base 218 includes a disk-shaped holding part 220 and a columnar shaft part 222 extending downward from the center of the lower surface of the holding part 220.

  A support unit 224 that rotatably supports the shaft portion 222 of the table base 218 is provided at the center of the bottom wall 206c. The support unit 224 includes a cylindrical fixing member 226 fixed to the center portion of the bottom wall 206c. A cylindrical rotating member 228 fixed to the shaft portion 222 is disposed inside the fixed member 226.

  The rotating member 228 is connected to the fixed member 226 via the radial bearing 230. A ring-shaped lip seal 232 is provided on the processing space side of the radial bearing 228. As the lip seal 232, for example, Omni-Seal (registered trademark) manufactured by Saint-Goban, Inc. can be used. The lip seal 232 can rotate the table base 218 while maintaining the airtightness of the processing space.

  A disc-shaped electrostatic chuck table 234 is provided on the upper surface of the holding unit 220. The electrostatic chuck table 234 includes a main body 236 formed of an insulating material and a plurality of electrodes 238 embedded in the main body 236, and holds the workpiece 11 by static electricity generated between the electrodes 238. Each electrode 238 is connected to a DC power supply 240 capable of generating a high voltage of about 5 kV, for example.

  Further, a suction path 236 a for sucking the workpiece 11 is formed in the main body 236 of the electrostatic chuck table 234. The suction path 236 a is connected to the suction pump 242 through a suction path 218 a formed inside the table base 218.

  When holding the workpiece 11 by the electrostatic chuck table 234, first, the second surface 21b of the support member 21 fixed to the workpiece 11 is brought into contact with the upper surface of the electrostatic chuck table 234, and the suction pump Activating 242. As a result, the support member 21 comes into close contact with the upper surface of the electrostatic chuck table 234 by the suction force of the suction pump 242. If a potential difference is generated between the electrodes 238 in this state, the support member 21 is attracted by static electricity and the workpiece 11 can be held.

  In addition, a cooling channel 218b is formed inside the table base 218. Both ends of the cooling channel 218b are connected to a circulation unit 244 for circulating the refrigerant. When the circulation unit 244 is operated, the refrigerant flows from one end of the cooling flow path 218b toward the other end, and the table base 218 and the like are cooled.

  A rotary drive unit 246 such as a motor is connected to the lower end of the shaft portion 222. The table base 218 and the electrostatic chuck table 234 are rotated by the rotational force of the rotation drive unit 246. A control unit 248 is connected to the rotation drive unit 246, and the rotation amount (rotation angle) of the table base 218 and the electrostatic chuck table 234 is controlled by the control unit 248.

  A nozzle unit 250 that supplies plasma (plasma etching gas) to the workpiece 11 is disposed above the electrostatic chuck table 234. The nozzle unit 250 includes a cylindrical first nozzle 252 that ejects plasma.

A plurality of gas supply sources are connected in parallel to the upstream end of the first nozzle 252. Specifically, for example, a first gas supply source 260a for supplying SF ₆ is connected via a valve 254a, a flow rate controller 256a, a valve 258a, etc., and via a valve 254b, a flow rate controller 256b, a valve 258b, etc. The second gas supply source 260b for supplying O ₂ is connected, and the third gas supply source 260c for supplying inert gas is connected via the valve 254c, the flow rate controller 256c, the valve 258c, and the like. .

  Thereby, a mixed gas in which a plurality of gases are mixed at a desired flow rate ratio can be supplied to the first nozzle 252. An electrode 262 for plasma generation is disposed in the midstream portion of the first nozzle 252. In addition, a high frequency power source 264 is connected to the electrode 262. The high frequency power supply 264 supplies a high frequency voltage of about 0.5 kV to 5 kV, 450 kHz to 2.45 GHz, for example, to the electrode 262.

  When a high frequency voltage is supplied to the electrode 262 while supplying a mixed gas that is a raw material of plasma, the mixed gas can be radicalized or ionized to generate plasma inside the first nozzle 252. The generated plasma is ejected from an ejection port 252 a formed at the downstream end of the first nozzle 252. The number of gas supply sources and the type of gas can be arbitrarily changed according to the material of the workpiece 11 (wafer 13). Moreover, the flow ratio of each gas is appropriately set within a range where plasma can be generated.

  A cylindrical second nozzle 266 having a larger diameter than the first nozzle 252 is disposed so as to surround the downstream side of the first nozzle 252. The upstream side of the second nozzle 266 is connected to an exhaust pump 270 via an exhaust unit 268 having an exhaust passage inside. On the other hand, the downstream end of the second nozzle 266 is positioned below the jet outlet 252a of the first nozzle 252 and serves as a discharge outlet 266a for discharging plasma or the like jetted from the jet outlet 252a to the outside.

  The lid 208 is provided with a support unit 272 that supports the nozzle unit 250 including the first nozzle 252 and the second nozzle 266. The support unit 272 includes a cylindrical fixing member 274 fixed to the lid 208. A columnar rotating member 276 that fixes the nozzle unit 250 is disposed inside the fixing member 274.

  The rotating member 276 is connected to the fixed member 274 via a radial bearing 278. On the processing space side of the radial bearing 278, a ring-shaped lip seal 280 configured similarly to the lip seal 232 is provided. The lip seal 280 can rotate the rotating member 276 while maintaining the airtightness of the processing space.

  A disc-shaped pulley member 282 is fixed to the upper portion of the rotating member 276. The pulley member 282 is connected to a rotational drive unit 286 such as a motor via a belt 284. The rotation member 276 rotates by the rotational force of the rotation drive unit 286 transmitted via the pulley member 282 and the belt 284.

  A control unit 288 is connected to the rotation drive unit 286, and the rotation amount (rotation angle) of the rotation member 276 is controlled by the control unit 288. By controlling the rotation amount of the rotating member 276 by the control unit 288, the nozzle unit 250 can be swung so as to draw a horizontal arcuate locus.

  Therefore, by controlling the rotation amount of the electrostatic chuck table 234 with the control unit 248 and controlling the position of the nozzle unit 250 with the control unit 288, the positional relationship between the workpiece 11 and the nozzle unit 250 can be freely set. Can be adjusted. Here, the rotational drive unit 246 and the rotational drive unit 286 are controlled by different control units 248 and control units 288, but the rotational drive unit 246 and the rotational drive unit 286 may be controlled by the same control unit.

  A pipe 290 is provided on another part of the side wall 206 a of the main body 206. The pipe 290 is connected to the third gas supply source 260c via a valve (not shown), a flow rate controller (not shown), and the like. The inert gas supplied from the third gas supply source 260 c through the pipe 290 becomes an inner gas that fills the processing space of the vacuum chamber 204.

  The mark recess forming step using the plasma etching apparatus 202 is performed in the following procedure. First, the gate 210 is lowered by the opening / closing unit 212. Next, the workpiece 11 is carried into the processing space of the vacuum chamber 204 through the opening 206b, and the workpiece 11 (and so on) is exposed so that the back surface 13b side of the wafer 13 processed by dry etching (plasma etching) is exposed upward. The support member 21) is placed on the upper surface of the electrostatic chuck table 234.

  Thereafter, the suction pump 242 is operated to bring the second surface 21 b of the support member 21 into close contact with the electrostatic chuck table 234. Then, a potential difference is generated between the electrodes 238, and the support member 21 is adsorbed by static electricity. Thereby, the workpiece 11 can be held by the electrostatic chuck table 234. Further, the gate 210 is raised by the opening / closing unit 212 to close the opening 206b, and the processing space is exhausted and decompressed by the exhaust pump 216.

For example, after the processing space is depressurized to about 200 Pa, the processing space is filled with an inert gas supplied from the third gas supply source 260 c through the pipe 290. As the inner gas filling the processing space, a rare gas such as Ar or He, a mixed gas obtained by mixing N ₂ , H ₂ or the like in a rare gas, or the like can be used. Further, the positional relationship between the workpiece 11 and the nozzle unit 250 is adjusted by controlling the rotation amount of the electrostatic chuck table 234 and the position of the nozzle unit 250.

FIG. 10 is a partial cross-sectional side view schematically showing how the workpiece 11 is processed by the plasma supplied from the nozzle unit 250. After aligning the nozzle unit 250 with a region (outer peripheral portion) in the vicinity of the outer peripheral edge that forms a concave portion as a mark, from the first gas supply source 260a, the second gas supply source 260b, and the third gas supply source 260c, SF ₆ , O ₂ , and inert gas are supplied at an arbitrary flow rate.

In addition, a high frequency voltage is supplied to the electrode 262 to radicalize or ionize a mixed gas of SF ₆ , O ₂ , and an inert gas. Thereby, the workpiece 11 can be processed by ejecting plasma (plasma etching gas) C from the ejection port 252 a of the first nozzle 252. The plasma C ejected from the ejection port 252a is sucked into the exhaust pump 270 through the exhaust port 266a and is discharged to the outside of the processing space.

  As shown in FIG. 10, the distance between the discharge port 266a located at the lower end of the nozzle unit 250 and the back surface 13b of the wafer 13 is sufficiently small. Specifically, for example, the thickness is 0.1 mm to 10 mm, preferably 1 mm to 2 mm. The area outside the nozzle unit 250 is filled with the inner gas D (inert gas).

  Therefore, the plasma C ejected from the ejection port 252a does not leak to the outside of the nozzle unit 250 and an unintended portion of the wafer 13 is not processed. That is, the plasma C can be supplied to only an arbitrary part of the wafer 13 and selectively processed.

  In the plasma etching apparatus 202, the positional relationship between the electrostatic chuck table 234 and the nozzle unit 250 is controlled by combining two types of rotational operations. Therefore, for example, it is easier to maintain the airtightness of the processing space as compared with the case where the positional relationship between the electrostatic chuck table 234 and the nozzle unit 250 is controlled by a linear operation. That is, the positional relationship between the workpiece 11 and the nozzle unit 250 can be adjusted while appropriately maintaining the airtightness of the processing space.

  FIG. 11A is a plan view schematically showing a state of the workpiece 11 after the mark recess forming step according to the modification, and FIG. 11B is a mark recess forming step according to the modification. It is sectional drawing which shows typically the state of the to-be-processed object 11 after. Based on the recess 13e formed in this way, the crystal orientation of the wafer 13 can be recognized.

  If there is no need to indicate the crystal orientation of the wafer 13, the above-described mark recess forming step may be omitted. In addition, the configurations, methods, and the like according to the above-described embodiments can be appropriately modified and implemented without departing from the scope of the object of the present invention.

11 Workpiece 11a Front 11b Back 13 Wafer (Substrate)
13a Front surface 13b Back surface 13c Chamfered portion 13d Uncut portion 13e Recessed portion 15 Functional layer 17 Device 21 Support member 21a First surface 21b Second surface 23 Adhesive layer (adhesive)
31 resist material 33 resist film 35 resist film 2 spin coating device 4 chuck table 4a holding surface 6 nozzle 22 cutting device 24 chuck table 24a holding surface 26 cutting unit 28 spindle 30 cutting blade 42 grinding device 44 chuck table 44a holding surface 46 grinding unit 48 Spindle housing 50 Spindle 52 Mount 54 Grinding wheel 56 Wheel base 58 Grinding wheel 102 Dry etching equipment (plasma etching equipment)
104 processing space 106 vacuum chamber 106a side wall 106b bottom wall 106c upper wall 108 opening 110 gate 112 opening / closing mechanism 114 exhaust port 116 exhaust device 118 lower electrode 120 upper electrode 122 holding unit 124 support unit 126 opening 128 bearing 130 high frequency power supply 132 table 134 suction Path 136 Suction source 138 Cooling flow path 140 Refrigerant introduction path 142 Circulating device 144 Refrigerant discharge path 146 Gas ejection section 148 Support section 150 Opening 152 Bearing 156 Lifting mechanism 158 Support arm 160 Jet outlet 162 Channel 164 Gas supply source 202 Dry etching apparatus (Plasma etching equipment)
204 Vacuum chamber 206 Main body 206a Side wall 206b Opening part 206c Bottom wall 208 Lid 210 Gate 212 Opening / closing unit 214 Pipe 216 Exhaust pump 218 Table base 218a Suction path 218b Cooling channel 220 Holding part 222 Shaft part 224 Support unit 226 Fixing member 228 Rotating member 230 Radial bearing 232 Lip seal 234 Electrostatic chuck table 236 Main body 236a Suction path 238 Electrode 240 DC power supply 242 Suction pump 244 Circulation unit 246 Rotation drive unit 248 Control unit 250 Nozzle unit 252 First nozzle 252a Ejection 254a, 254b, 254c, 258a, 258b, 258c Valves 256a, 256b, 256c Flow rate controller 260a First gas supply source 260b Second gas supply source 260c Third gas supply source 262 Electrode 264 High frequency power supply 266 Second nozzle 266a Discharge port 268 Exhaust unit 270 Exhaust pump 272 Support unit 274 Fixed member 276 Rotating member 278 Radial bearing 280 Lip seal 282 Pulley member 284 Belt 286 Rotation drive unit 288 Control unit 290 Piping

Claims (2)

A workpiece processing method for processing a workpiece in which a functional layer to be a part of a device is formed on a surface side of a substrate having a chamfered portion chamfered on an outer periphery,
A support member fixing step for fixing the support member to the surface side of the workpiece having the functional layer via an adhesive;
After carrying out the supporting member fixing step, a rotating cutting blade is cut from the back surface side of the workpiece to the depth not reaching the functional layer along the outer peripheral edge, and a part of the chamfered portion is removed to remove the substrate. An outer periphery cutting step for leaving a left uncut portion along the outer periphery on the surface side of
After performing the outer peripheral edge cutting step, the dry etching step of removing the uncut portion by dry etching to expose the functional layer overlapping the uncut portion on the back side of the workpiece;
And a thinning step of thinning the workpiece by grinding the back side of the substrate after performing the dry etching step.   After carrying out the thinning step, the method further comprises a mark recess forming step for forming a recess serving as a mark indicating the crystal orientation of the substrate by processing the outer peripheral portion on the back side of the substrate by local dry etching. A processing method for a workpiece according to claim 1.

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