JP2022029511A - Wafer processing method - Google Patents

Abstract

To provide a wafer processing method of providing a protective member on one surface of a wafer and then grinding the other surface of the wafer, in which the wafer can be flattened even in a case in which the wafer is changed in shape as the protective member is formed.SOLUTION: Depending on an amount of change obtained by calculating heights of the other surface of a wafer before and after a protective member is formed, at least one of an inclination of a rotation axis of a holding surface of a chuck table and an inclination of a rotation axis of a grinding surface defined by a lower surface of a grinding wheel is adjusted, and the other surface of the wafer is ground. Accordingly, the other surface of the wafer can be ground so as to cancel deformation of the wafer associated with formation of the protective member. As a result, a wafer can be provided in which, after separating the protective member from one surface, the other surface is flattened.SELECTED DRAWING: Figure 5

Description

The present invention relates to a method for processing a wafer.

Chips of semiconductor devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) are indispensable configurations in various electronic devices such as mobile phones and personal computers. Such chips are manufactured using disc-shaped wafers made of semiconductors such as silicon (Si), silicon carbide (SiC) and gallium arsenide (GaAs).

The disk-shaped wafer is generally cut out from a columnar ingot using a blade saw, a wire saw, or the like. The shape of the wafer cut out in this way often includes a curve (warp) over the entire area. Therefore, wafers cut out from ingots are often flattened by removing warpage prior to being used to manufacture chips for semiconductor devices.

Wafers cut out from the ingot are flattened, for example, by wrapping. However, it is difficult to completely remove the warp by wrapping the wafer.

The wafer can also be flattened by grinding the surface of the wafer. However, the grinding of the wafer is generally performed in a state where the wafer is attracted and held by the chuck table.

When the wafer is sucked in this way, the shape including the warp peculiar to the wafer is corrected to a flat shape. Therefore, it is difficult to completely remove the warp by grinding the wafer in this state, and the wafer separated from the chuck table often has a shape in which the warp remains.

As an effective method for removing the warp contained in the shape of a wafer, a method of providing a cured ultraviolet curable resin on one surface of the wafer and then grinding the other surface of the wafer is known (). See Patent Document 1). In this method, for example, the ultraviolet curable resin cured on one surface of the wafer is provided in the following order.

First, the ultraviolet curable resin is applied to one surface of the wafer. The wafer is then held on the holding surface of the stage so as to expose the other side of the wafer coated with the UV curable resin. Next, the wafer held on the holding surface of the stage is pressed by the pressing means from the other surface side of the wafer in the direction perpendicular to the holding surface of the stage. Next, after the pressing means is separated from the wafer, the ultraviolet curable resin is irradiated with ultraviolet light by the ultraviolet irradiation means to cure the ultraviolet curable resin.

According to this method, a cured ultraviolet curable resin (protective member) is formed on one surface of the wafer in a state where the pressure from the pressing means is not applied to the wafer. That is, the protective member is formed on one surface of the wafer without causing an internal stress that greatly deforms the shape of the wafer from the shape at the time of being cut out from the ingot.

Then, according to this method, the wafer can be ground while the wafer is attracted and held by the chuck table via the protective member. That is, the wafer can be ground in a shape close to the shape of the wafer at the time of cutting out from the ingot. This suppresses the occurrence of problems such as the wafer separated from the chuck table having a shape including warpage.

Japanese Unexamined Patent Publication No. 2009-148866

In the above method, in order to spread the ultraviolet curable resin coated on one surface of the wafer as a whole, the wafer held on the holding surface of the stage is pressed from the other surface side of the wafer by the pressing means to the holding surface of the stage. Press in the direction perpendicular to.

Here, the holding surface and the pressing surface of the pressing means in contact with the other surface of the wafer are not always flat at the micron level, and are not necessarily parallel to each other at the micron level. Further, if the pressing means is separated from the wafer, the wafer tries to restore itself to the shape at the time of being cut out from the ingot, but since one surface of the wafer has a highly viscous ultraviolet curable resin adhered to it. There is a high probability that the wafer will not completely return to its original shape.

Therefore, the ultraviolet curable resin can be cured in a state where the flatness and parallelism of the holding surface of the stage and the pressing surface of the pressing means are reflected. In this case, the shape of the cured ultraviolet curable resin (protective member) may be transferred to the shape of the wafer. As a result, the wafer may be deformed so that the amount of deformation changes from the center toward the outer circumference, and a concentric pattern may be formed on the wafer.

Due to such an influence, the shape of the wafer at the time when the protective member is formed on one surface may be further changed from the shape of the wafer at the time when the protective member is cut out from the ingot. Therefore, even if it seems that the warp caused by cutting out from the ingot is removed by grinding the other surface of this wafer and flattening it in appearance, the shape of the wafer due to the formation of the protective member is obtained. There is a risk that the effects of will remain.

In view of the above points, an object of the present invention is a method for processing a wafer in which a protective member is provided on one surface of the wafer and then the other surface of the wafer is ground, and the wafer is formed with the formation of the protective member. It is an object of the present invention to provide a method for processing a wafer capable of flattening the wafer even when the shape of the wafer changes.

According to the present invention, a protective member forming device for curing a liquid ultraviolet curable resin provided on the entire one surface of a wafer to form a protective member, and a protective member via the protective member on a conical holding surface of a chuck table. A method for processing a wafer using a grinding device that holds the wafer and grinds the other surface of the wafer with a grinding wheel to flatten the wafer, a table having a support surface, and a table having a support surface. It is possible to measure the height of the upper surface of the object to be measured placed on the support surface from the support surface, and it is possible to move in a direction relatively parallel to the support surface with respect to the table. A height measuring device including a measuring unit is used to measure the height of one or more points of the other surface of the wafer in a state where one surface of the wafer is in contact with the support surface. A measurement step, a protective member forming step for forming the protective member using the protective member forming device, and the height measuring instrument, with the protective member in contact with the support surface, the first step. A second measurement step that measures the height of the other surface of the wafer at a point corresponding to the point where the height was measured in one measurement step, and the height of one or more points measured in the first measurement step. And the amount of change in the height of one or more points on the other surface of the wafer that has changed due to the formation of the protective member with reference to the height of the corresponding points measured in the second measurement step. The change amount calculation step for calculating the change amount, and the other surface of the wafer obtained in the change amount calculation step while the wafer is held by the holding surface via the protective member using the grinding device. The axis of rotation of the holding surface so that the other surface of the wafer becomes flat when the protective member is removed from one surface of the wafer, depending on the amount of change in height at one or more points. A method for processing a wafer, comprising a grinding step of adjusting at least one of an inclination and an inclination of a rotation axis of a grinding surface defined by the lower surface of the grinding wheel to grind the other surface of the wafer with the grinding wheel. Is provided.

Preferably, after the grinding step, a second grinding step is performed in which one surface of the wafer is ground by the grinding wheel while the other surface of the wafer is held by the holding surface using the grinding device. Further included, in the second grinding step, the inclination of the rotation axis of the holding surface and the rotation axis of the grinding surface so that the bus of the holding surface closest to the grinding surface and the grinding surface are parallel to each other. Grind with the grinding wheel by adjusting at least one of the inclinations.

Preferably, between the grinding step and the second grinding step, a peeling step of peeling the protective member from one surface of the wafer is further included.

Preferably, the location where the height is measured in each of the first measurement step and the second measurement step includes a location located at the center of the other surface of the wafer and a location located at the outer periphery.

Preferably, the grinding device comprises a grinding unit equipped with a grinding wheel having the grinding wheel and an annular wheel base having the grinding wheel arranged in an annular shape on one side thereof, and the chuck table holds the chuck table. Further, a rotation drive source for rotating the holding surface with a straight line passing through the center of the surface as a rotation axis, and an inclination adjusting unit for adjusting the inclination of the rotation axis of the holding surface are further provided.

In the present invention, the inclination of the rotation axis of the holding surface of the chuck table and the lower surface of the grinding wheel depend on the amount of change obtained by calculating the height of the other surface of the wafer before and after the protective member is formed. The other surface of the wafer is ground by adjusting at least one of the inclinations of the rotation axis of the specified grinding surface.

This makes it possible to grind the other surface of the wafer so as to offset the deformation of the wafer due to the formation of the protective member. As a result, it is possible to provide a wafer in which the other surface becomes flat after the protective member is peeled off from one surface.

FIG. 1 is a cross-sectional view schematically showing a wafer. FIG. 2 is a perspective view schematically showing a protective member forming device. FIG. 3 is a perspective view schematically showing the grinding device. FIG. 4 is a partial cross-sectional side view schematically showing a part of the components of the grinding apparatus. FIG. 5 is a flowchart schematically showing an example of a wafer processing method. FIG. 6 is a perspective view schematically showing the height measuring instrument. FIG. 7 is a perspective view schematically showing a part of the components of the wafer and the height measuring instrument when measuring the height of one or more points on the other surface of the wafer. FIG. 8 is a partial cross-sectional side view schematically showing the wafer conveyed on the stage. FIG. 9 is a partial cross-sectional side view schematically showing the ultraviolet curable resin dropped on the stage and the wafer sucked and held by the pressing plate. FIG. 10 is a partial cross-sectional side view schematically showing the ultraviolet curable resin expanded by the pressing plate and the wafer separated from the pressing plate. FIG. 11 is a partial cross-sectional side view schematically showing the cured ultraviolet curable resin (protective member) and the wafer. FIG. 12 is a partial cross-sectional side view schematically showing a part of the components of the wafer and the grinding apparatus when grinding the other surface of the wafer. FIG. 13 is a top view schematically showing a chuck table of a grinding device for grinding the other surface of a wafer. FIG. 14 is a flowchart schematically showing another example of the wafer processing method.

An embodiment of the present invention will be described with reference to the accompanying drawings. First, the wafer to be processed in the present invention will be described. FIG. 1 is a cross-sectional view schematically showing a wafer 1 which is an example of such a wafer.

The wafer 1 is cut out from a columnar ingot using a blade saw, a wire saw, or the like. The ingot is made of semiconductors such as, for example, silicon (Si), silicon carbide (SiC) and gallium arsenide (GaAs), and has a diameter of, for example, 6 to 12 inches. Further, the wafer 1 is formed with a notch or an orientation flat (orientation flat) for indicating the crystal orientation.

As shown in FIG. 1, the wafer 1 has a shape including an entire curve (warp). The warp of the wafer 1 is generated due to the difference between the processing strain generated on one surface 1a and the processing strain generated on the other surface 1b when the wafer 1 is cut out from the ingot using a blade saw, a wire saw, or the like. ..

Specifically, when the machining strain generated on one surface 1a is smaller than the machining strain generated on the other surface 1b, as shown in FIG. 1, one surface 1a has a concave shape as a whole and has a concave shape. The wafer 1 is generally curved so that the other surface 1b has an overall convex shape.

Since the wafer 1 has a shape including warpage, the height from the flat surface when the wafer 1 is arranged on the flat surface is different for each place on one surface 1a and the other surface 1b. Change. For example, the difference between the top-positioned portion and the bottom-positioned portion on one surface 1a or the other surface 1b of the wafer 1 is 10 to 20 μm.

The above-mentioned wafer 1 is an example of a wafer to be processed in the present invention, and the wafer to be processed in the present invention is not limited to the wafer 1 shown in FIG.

Next, a protective member forming apparatus used for forming the protective member on one surface 1a of the wafer 1 will be described. FIG. 2 is a perspective view schematically showing the protective member forming apparatus 2 which is an example of such a protective member forming apparatus.

The protective member forming device 2 has a rectangular parallelepiped base 4 having an internal space. At the upper part of the base 4, a stage 6 having a substantially flat upper surface is arranged so as to close the internal space. The stage 6 is made of a material that transmits ultraviolet rays, such as borosilicate glass, quartz glass, and translucent alumina.

A light source 8 that radiates ultraviolet rays is arranged below the stage 6. A shutter 10 for blocking ultraviolet rays from the light source 8 is provided between the stage 6 and the light source 8. Further, above the shutter 10, for example, a filter 12 that blocks light having a wavelength that is not necessary for curing the ultraviolet curable resin is arranged.

When the shutter 10 is closed, the ultraviolet rays from the light source 8 are blocked by the shutter 10 and do not reach the stage 6. On the other hand, when the shutter 10 is opened, the ultraviolet rays from the light source 8 pass through the filter 12 and the stage 6.

An exhaust pipe 14 connected to an exhaust pump (not shown) or the like is provided on the side wall of the base 4. In the protective member forming device 2, if the temperature of the internal space of the base 4 rises due to the radiation of ultraviolet rays by the light source 8, the stage 6 may be deformed and the flatness of the upper surface (support surface) may be deteriorated. be. Therefore, by exhausting the internal space of the base 4 through the exhaust pipe 14, the temperature rise of the internal space of the base 4 is suppressed.

A support structure 16 is provided at a position adjacent to the stage 6. The support structure 16 includes a pillar portion 16a extending upward from the base 4, and an eaves portion 16b extending horizontally from the upper end of the pillar portion 16a. A pressing mechanism 18 is provided at the center of the eaves 16b.

The pressing mechanism 18 is provided so as to penetrate the main rod 20 provided through the central portion of the eaves portion 16b so as to be orthogonal to the eaves portion 16b, and to penetrate the eaves portion 16b substantially parallel to the main rod 20. Includes a plurality of secondary rods 22. The plurality of sub rods 22 are arranged at substantially equal intervals so as to surround the main rod 20.

A disk-shaped pressing plate 24 is fixed to the lower end of the main rod 20 and the lower ends of the plurality of sub rods 22. Further, a porous plate (not shown) whose lower surface is exposed is provided at the lower part of the pressing plate 24. This porous plate is connected to a suction source (not shown), and when the suction source is operated, a negative pressure is generated on the lower surface (suction surface) of the porous plate.

Further, each of the main rod 20 and the plurality of sub rods 22 is connected to an elevating mechanism (not shown) including a motor and the like. By lowering the main rod 20 and the plurality of auxiliary rods 22, the elevating mechanism can apply pressure to the pressed object arranged between the stage 6 and the pressing plate 24. The elevating mechanism can independently raise and lower the main rod 20 and the plurality of sub rods 22 to adjust the pressure applied to the object to be pressed.

Further, the elevating mechanism can raise the main rod 20 and the plurality of sub rods 22 while the pressed object is sucked and held through the porous plate provided at the lower part of the pressing plate 24. As a result, the pressed object can be moved upward from the stage 6.

In the protective member forming device 2 shown in FIG. 2, for example, protective members that come into contact with the lower surface of the pressed object are formed in the following order.

First, the object to be pressed is carried onto the stage 6. Next, the suction source connected to the porous plate is operated in a state where the porous plate provided at the lower part of the pressing plate 24 is in contact with the object to be pressed. As a result, the pressing plate 24 sucks and holds the pressed object via the porous plate.

Next, the pressing plate 24 that sucks and holds the object to be pressed is moved upward from the stage 6. Next, after dropping the liquid ultraviolet curable resin onto the stage 6, the pressing plate 24 is lowered to spread the ultraviolet curable resin over the entire lower surface of the object to be pressed.

At this time, the amount of lowering of the pressing plate 24, the pressure applied to the object to be pressed, the amount of the ultraviolet curable resin dropped on the stage 6 and the type of resin so that the thickness of the ultraviolet curable resin becomes a desired thickness. At least one is set. Then, the suction source connected to the porous plate is stopped. As a result, the pressing plate 24 and the pressed object are separated.

Next, the pressing plate 24 separated from the object to be pressed is moved upward from the stage 6. Then, the shutter 10 is opened. Next, the ultraviolet curable resin is irradiated with ultraviolet rays from the light source 8 via the filter 12 and the stage 6. As a result, the ultraviolet curable resin existing on the lower surface side of the object to be pressed is cured.

As a result, a cured ultraviolet curable resin (protective member) having a desired thickness is formed that comes into contact with the lower surface of the object to be pressed. The above-mentioned protective member forming apparatus 2 is an example of the protective member forming apparatus used in the present invention, and the protective member forming apparatus used in the present invention is not limited to the protective member forming apparatus 2 shown in FIG.

Next, a grinding device used for holding the wafer 1 via a protective member and grinding the other surface 1b of the wafer 1 with a grinding wheel to flatten it will be described. FIG. 3 is a perspective view schematically showing a grinding device 30 which is an example of such a grinding device. The X-axis direction, the Y-axis direction, and the Z-axis direction shown in FIG. 1 are orthogonal to each other. Further, the Z-axis direction can also be expressed as a vertical direction, a vertical direction, or a grinding feed direction.

The grinding device 30 has a base 32 on which each component is mounted. An opening 32a having a longitudinal portion along the X-axis direction is formed on the upper surface of the base 32. A ball screw type X-axis direction moving mechanism 34 is arranged inside the opening 32a.

The X-axis direction moving mechanism 34 has a pair of guide rails (not shown) arranged along the X-axis direction. A ball screw (not shown) is arranged between the pair of guide rails along the X-axis direction. A pulse motor (not shown) for rotating the ball screw is connected to one end of the ball screw.

A nut portion (not shown) provided on the lower surface side of the X-axis moving table (not shown) is connected to the ball screw in a rotatable manner. If the ball screw is rotated by the pulse motor, the X-axis moving table moves along the X-axis direction.

A table cover 34a is provided on the X-axis moving table. Further, a chuck table 36 is provided on the table cover 34a. Here, the chuck table 36 and the like will be described with reference to FIG. Note that FIG. 4 is a partial cross-sectional side view schematically showing a part of the components of the grinding apparatus 30 such as the chuck table 36.

The chuck table 36 has a disk-shaped frame 38 made of ceramics. The frame body 38 has an annular side wall, and a recess is defined by this side wall. A suction path (not shown) is formed at the bottom of the recess. One end of the suction path is exposed on the bottom surface of the recess, and the other end of the suction path is connected to a suction source (not shown) such as an ejector.

A porous plate 40 is fixed to the recess of the frame body 38. The lower surface of the porous plate 40 is generally flat, but the lower surface thereof is a conical surface whose central portion slightly protrudes from the outer peripheral portion. When the suction source is operated, a negative pressure is generated on the conical surface (holding surface of the chuck table 36) 40a of the porous plate 40.

The upper part of the cylindrical spindle 42 is connected to the lower part of the chuck table 36. The spindle 42 has a rotary drive source (not shown) such as a servo motor. When this rotation drive source is operated, the chuck table 36 rotates about the rotation shaft 44 passing through the center of the holding surface 40a.

Below the chuck table 36, an annular bearing 46 that supports the chuck table 36 in such a manner that the chuck table 36 can rotate is provided. An annular support plate 48 is fixed below the bearing 46. An annular table base 50 is provided below the support plate 48. The spindle 42 is located at the central opening of the annular bearing 46, the central opening of the annular support plate 48 and the central opening of the annular table base 50.

A load detection unit 52 is arranged between the lower surface of the support plate 48 and the upper surface of the table base 50. The load detection unit 52 has three load measuring instruments 52a. The three load measuring instruments 52a are provided apart from each other along the circumferential direction of the upper surface of the table base 50. The upper surface of the load measuring instrument 52a is in contact with the lower surface of the support plate 48. The load measuring device 52a is, for example, a diaphragm type load cell.

The load measuring device 52a may be a column type load cell. The load cell includes a sensor that converts the load into an electrical signal. The load cell has, for example, a piezoelectric sensor having a piezoelectric element, but may have a strain gauge type sensor, a capacitance type sensor, or the like instead.

The chuck table 36 is supported by the table base 50 via a bearing 46, a support plate 48, and a load detection unit 52. Therefore, when the holding surface 40a is pressed, the load (grinding load) applied to the table base 50 is measured by the load detection unit 52.

On the lower surface side of the table base 50, three support mechanisms (fixed support mechanism 54a, first movable support mechanism 54b, and second movable support mechanism 54c) are provided so as to be separated from each other along the circumferential direction of the table base 50. ing. Each support mechanism is arranged directly below the load measuring instrument 52a. In this specification, these three support mechanisms are collectively referred to as an inclination adjusting unit 54.

A part of the table base 50 is supported by the fixed support mechanism 54a. The fixed support mechanism 54a has a support column (fixed shaft) having a predetermined length. The upper part of the support is fixed to the upper support fixed to the lower surface of the table base 50, and the lower part of the support is fixed to the support base.

Further, the other two parts of the table base 50 are supported by the first movable support mechanism 54b and the second movable support mechanism 54c. Each of the first movable support mechanism 54b and the second movable support mechanism 54c has a support column (movable shaft) 56 having a male screw formed at the tip thereof.

The tip (upper part) of the support column 56 is rotatably connected to the upper support 58 fixed to the lower surface of the table base 50. More specifically, the upper support 58 is a metal columnar member such as a rod having a screw hole, and the male screw of the support 56 is connected to the screw hole of the upper support 58 in a rotatable manner.

A ring-shaped bearing 60 having a predetermined outer diameter is fixed to the outer periphery of the support column 56 of the first movable support mechanism 54b and the second movable support mechanism 54c. A part of the bearing 60 is supported by a stepped support plate 62. That is, the first movable support mechanism 54b and the second movable support mechanism 54c are supported by the support plate 62.

A pulse motor 64 for rotating the support column 56 is connected to the lower part of the support column 56. By operating the pulse motor 64 to rotate the support column 56 in one direction, the upper support 58 is raised. Further, by operating the pulse motor 64 to rotate the support column 56 in the other direction, the upper support 58 is lowered. By moving the upper support 58 up and down in this way, the inclination of the table base 50 (that is, the chuck table 36) is adjusted.

The other components of the grinding apparatus 30 will be described again with reference to FIG. The opening 32a is provided with a bellows-shaped dust-proof / drip-proof cover 66 that can be expanded and contracted in the X-axis direction so as to sandwich the table cover 34a.

An operation panel 68 for inputting grinding conditions and the like is provided in the vicinity of one end of the opening 32a. Further, near the other end of the opening 32a, a rectangular parallelepiped support structure 70 extending upward is provided.

A Z-axis direction moving mechanism 72 is provided on the front surface side (that is, the operation panel 68 side) of the support structure 70. The Z-axis direction moving mechanism 72 includes a pair of Z-axis guide rails 74 arranged along the Z-axis direction.

A Z-axis moving plate 76 is attached to the pair of Z-axis guide rails 74 so as to be slidable along the Z-axis direction. A nut portion (not shown) is provided on the rear surface side (rear surface side) of the Z-axis moving plate 76.

A Z-axis ball screw 78 arranged along the Z-axis direction is coupled to the nut portion in a rotatable manner. A Z-axis pulse motor 80 is connected to one end of the Z-axis ball screw 78 in the Z-axis direction.

When the Z-axis ball screw 78 is rotated by the Z-axis pulse motor 80, the Z-axis moving plate 76 moves in the Z-axis direction along the Z-axis guide rail 74. A support 82 is provided on the front surface side of the Z-axis moving plate 76.

The support 82 supports the grinding unit 84. The grinding unit 84 has a cylindrical spindle housing 86 fixed to a support 82. A part of the columnar spindle 88 along the Z-axis direction is housed in the spindle housing 86 in a rotatable state.

A servomotor 90 for rotating the spindle 88 is connected to the upper end of the spindle 88. The lower end of the spindle 88 is exposed from the spindle housing 86, and the upper surface of the disk-shaped wheel mount 92 made of a metal material such as stainless steel is fixed to the lower end.

An annular grinding wheel 94 having a diameter substantially equal to that of the wheel mount 92 is attached to the lower surface of the wheel mount 92. As shown in FIG. 4, the grinding wheel 94 has an annular wheel base 96 made of a metal material such as stainless steel. On the lower surface side of the wheel base 96, a plurality of grinding wheels 98 are discretely arranged along the circumferential direction of the lower surface.

The lower surfaces of the plurality of grinding wheels 98 are arranged at substantially the same height in the Z-axis direction, and the lower surfaces define a grinding surface 98a for grinding the object to be ground. When the servo motor 90 operates to rotate the spindle 88, the grinding wheel 94 rotates about a rotating shaft 100 passing through the center of the grinding surface 98a.

In the grinding apparatus 30 shown in FIGS. 3 and 4, for example, the upper surface of the object to be ground is ground in the following order.

First, the object to be ground is carried onto the holding surface 40a of the chuck table 36. Next, the suction source connected to the porous plate 40 via the suction path is operated to suck and hold the object to be ground through the porous plate 40. As a result, the object to be ground is slightly deformed according to the shape of the holding surface 40a of the conical chuck table 36.

Next, the servo motor (not shown) operates to rotate the spindle 42 to rotate the chuck table 36, and the servo motor 90 operates to rotate the spindle 88 to rotate the grinding wheel 94. Next, the Z-axis pulse motor 80 operates to rotate the Z-axis ball screw 78, thereby lowering the Z-axis moving plate 76.

As a result, the upper surface of the object to be ground and the grinding wheel 98 come into contact with each other while rotating. As a result, the upper surface of the object to be ground is ground. The above-mentioned grinding device 30 is an example of the grinding device used in the present invention, and the grinding device used in the present invention is not limited to the grinding device 30 shown in FIGS. 3 and 4.

Next, a method for processing the wafer 1 will be described in which the protective member is formed on one surface 1a of the wafer 1 using the protective member forming device 2, and then the other surface 1b of the wafer 1 is ground using the grinding device 30. FIG. 5 is a flowchart schematically showing an example of such a processing method of the wafer 1.

In this processing method, first, the height of one or more points on the other surface 1b of the wafer 1 is measured by using a height measuring device (first measurement step: S1). The height measuring device used for this measurement may be either a contact type height measuring device or a non-contact type height measuring device.

However, when a contact-type height measuring instrument is used, the height of the other surface 1b of the wafer 1 changes due to pressure applied when the height measuring instrument comes into contact with the other surface 1b of the wafer 1 during measurement. There is a risk. Therefore, as the height measuring device used in the first measuring step (S1), a non-contact height measuring device is preferable.

As a non-contact height measuring instrument, for example, the height of the surface of the object to be measured is measured by irradiating the object to be measured with a laser beam and detecting the laser beam reflected by the surface of the object to be measured. Examples include measuring instruments for measuring.

FIG. 6 is a perspective view schematically showing a height measuring device 102, which is an example of a height measuring device used for measuring the height of the other surface 1b of the wafer 1. The A-axis direction and the B-axis direction shown in FIG. 6 are directions orthogonal to each other.

The height measuring instrument 102 has a flat rectangular parallelepiped base 104. A sliding plate 106 is provided on the base 104. The sliding plate 106 has an A-axis sliding plate 106a provided on the base 104 and a B-axis sliding plate 106b provided on the A-axis sliding plate 106a.

The shape of each of the A-axis sliding plate 106a and the B-axis sliding plate 106b is a flat rectangular parallelepiped shape. A columnar table 108 is provided on the central portion of the B-axis direction sliding plate 106b. The lower part of the table 108 is fixed to the upper part of the B-axis direction sliding plate 106b. In the height measuring instrument 102, the upper surface of the table 108 is the support surface 108a that supports the object to be measured.

Further, the sliding plate 106 is connected to a sliding mechanism (not shown) including a motor and the like. By independently sliding the A-axis direction sliding plate 106a and the B-axis direction sliding plate 106b by this sliding mechanism, the table 108 can be set to the desired coordinates in the coordinate system (AB coordinate plane) having the A-axis and the B-axis as the coordinate axes. Can be moved.

A rectangular parallelepiped support structure 110 extending upward is connected to the side wall of the base 104. A support arm 112 extending along the A-axis direction is provided on the front surface side (that is, the table 108 side) of the support structure 110. A measurement unit 114 is provided at the tip of the support arm 112.

The measurement unit 114 has a laser oscillator (not shown) that irradiates a laser beam toward the upper surface (support surface) 108a of the table 108, an optical sensor (not shown) that detects a laser beam reflected on the table 108 side, and the like. .. Further, the height measuring instrument 102 has a built-in control unit (not shown) that controls the operation of each component.

This control unit controls the operation of the sliding mechanism connected to the sliding plate 106 and the irradiation of the laser beam from the measuring unit 114 so that the height of the object to be measured is measured at the target location. do. Further, when the measurement unit 114 detects the laser beam reflected by the upper surface of the object to be measured, this control unit calculates the height of the upper surface of the object to be measured from the support surface 108a.

FIG. 7 is a perspective view schematically showing a part of the components of the wafer 1 and the height measuring device 102 when measuring the height of the portion 1b-1 of the other surface 1b of the wafer 1. The portion 1b-1 is a portion located at the center of the other surface 1b of the wafer 1.

When measuring the height of the portion 1b-1 using the height measuring device 102, first, the wafer 1 is placed on the support surface 108a so that one surface 1a of the wafer 1 is in contact with the support surface 108a. Next, the control unit controls the operation of the sliding mechanism connected to the sliding plate 106 so that the point 1b-1 is irradiated with the laser beam from the measuring unit 114, and adjusts the position of the table 108.

Next, the control unit controls the measurement unit 114 to irradiate the laser beam L1 from the measurement unit 114 toward the location 1b-1. Next, when the reflected laser beam L2 is detected in the measuring unit 114, the control unit calculates the height of the location 1b-1.

In the second height measurement (second measurement step: S3) described later, the other surface of the wafer 1 at the location corresponding to the location where the height was measured in this measurement (first measurement step: S1). It is necessary to measure the height of 1b. Therefore, in the first measurement step, it is necessary to associate the coordinates in the AB coordinate plane with the location of the other surface 1b of the wafer 1 on which the measurement has been made.

For example, with the notch 1c of the wafer 1 arranged at a predetermined position on the support surface 108a, the control unit may store the coordinates in the AB coordinate plane corresponding to the location where the measurement was made. Alternatively, the coordinates in the AB coordinate plane may be associated with the location of the other surface 1b of the wafer 1 on which the measurement has been made by the following procedure.

First, the laser beam is scanned in a circular motion in a region slightly inside the outer peripheral edge of the wafer 1. Next, since the height measured at the notch 1c becomes 0, the control unit stores the coordinates in the AB coordinate plane corresponding to the location where the height becomes 0. Next, the height of the other surface 1b of the wafer 1 is measured at an arbitrary position. Next, the control unit stores the coordinates in the AB coordinate plane corresponding to the location where the measurement was made.

As a result, the relative positional relationship between the coordinates in the AB coordinate plane corresponding to the location where the height becomes 0 and the coordinates in the AB coordinate plane corresponding to the location of the other surface 1b of the wafer 1 measured can be grasped. Will be done. Then, in the second measurement step (S3) as well, if the coordinates in the AB coordinate plane corresponding to the location where the notch 1c exists are detected, the relative positional relationship grasped in the first measurement step (S1) is obtained. Based on this, the coordinates of the point where the height should be measured in the AB coordinate plane are found.

Further, this measurement (first measurement step: S1) may be performed on a plurality of points on the other surface 1b of the wafer 1. For example, in this measurement, the heights of two locations, one located at the center of the other surface 1b of the wafer 1 and the other located at the outer peripheral portion, may be measured. Alternatively, in this measurement, a portion located in the central portion of the other surface 1b of the wafer 1, a portion located in the outer peripheral portion, and a portion located in the intermediate portion existing between the central portion and the outer peripheral portion. You may measure the height of three places.

When the first measurement step (S1) is completed, the protective member is formed on one surface 1a of the wafer 1 by using the protective member forming apparatus 2 shown in FIG. 2 (protective member forming step: S2). 8 to 11 are schematic views showing a process of forming a protective member on one surface 1a of the wafer 1.

When forming a protective member on one surface 1a of the wafer 1 using the protective member forming apparatus 2, first, the wafer 1 is carried onto the stage 6 so that the one surface 1a of the wafer 1 faces downward. .. For example, the wafer 1 is carried onto the stage 6 in a state of being mounted on the film 3 conveyed from the left front side to the right rear side of the protective member forming apparatus 2 shown in FIG. 2 (see FIG. 8).

Next, the pressing plate 24 is lowered to bring the lower surface of the pressing plate 24 into contact with the other surface 1b of the wafer 1. Next, the wafer 1 is sucked and held on the lower surface of the pressing plate 24. As described above, the suction holding of the wafer 1 is performed via the porous plate provided in the lower part of the pressing plate 24. Further, when the wafer 1 is sucked and held by the pressing plate 24, the wafer 1 is straightened into a flat shape due to the influence of the negative pressure generated on the lower surface of the porous plate.

Next, the pressing plate 24 that sucks and holds the wafer 1 is raised. Next, the liquid ultraviolet curable resin 5 is dropped onto the film 3 remaining on the stage 6. Then, the pressing plate 24 is lowered (see FIG. 9). As a result, one surface 1a of the wafer 1 and the liquid ultraviolet curable resin 5 come into contact with each other, and the liquid ultraviolet curable resin 5 is spread between the upper surface of the film 3 and the one surface 1a of the wafer 1.

Next, the wafer 1 is separated from the porous plate provided at the lower part of the pressing plate 24. Specifically, the operation of the suction source connected to this porous plate is stopped. As a result, the wafer 1 returns from a flat shape to a non-flat shape including warpage. Next, the pressing plate 24 is raised (see FIG. 10).

Next, with the shutter 10 (FIG. 2) open, ultraviolet rays are irradiated upward from the light source 8 (see FIG. 11). As a result, the ultraviolet curable resin 5 is irradiated with ultraviolet rays via the stage 6 and the like, and the cured ultraviolet curable resin (protective member) 5'is formed on one surface 1a of the wafer 1.

Here, the lower surface of the pressing plate 24 that presses the wafer 1 (the lower surface of the porous plate) and the upper surface of the stage 6 that supports the wafer 1 via the film 3 are not always flat at the micron level. , Not necessarily parallel to each other at the micron level. Further, if the pressing plate 24 is separated from the wafer 1, the wafer 1 tries to restore itself to the shape at the time when it is cut out from the ingot, but the one surface 1a of the wafer 1 has a highly viscous ultraviolet curable resin 5. It is highly probable that the wafer 1 will not be completely restored to its original shape due to the adhesion of the wafer 1.

Therefore, the ultraviolet curable resin 5 can be cured in a state where the flatness and parallelism of the surface in contact with the upper surface of the stage 6 and the lower surface of the pressing plate 24 (the lower surface of the porous plate) are reflected. In this case, the shape of the cured ultraviolet curable resin (protective member) 5'may be transferred to the shape of the wafer 1.

As a result, by providing the protective member 5'on one surface 1a of the wafer 1, the wafer 1 is deformed so that the amount of deformation changes from the center toward the outer circumference, and a concentric pattern is formed on the wafer 1. May be done. For example, comparing the shape of the wafer 1 shown in FIG. 8 with the shape of the wafer 1 shown in FIG. 11, the latter shape is apparently less warped than the former shape.

Therefore, in order to calculate the amount of deformation of the wafer 1 due to the provision of the protective member 5', after the protective member forming step (S2) is completed, the height measuring instrument 102 shown in FIG. 6 is used again. The height of the portion corresponding to the portion where the height was measured in the first measurement step (S1) is measured (second measurement step: S3). This measurement is performed, for example, in the following order.

First, the wafer 1 and the protective member 5'are placed on the support surface 108a so that the protective member 5'is in contact with the support surface 108a. Next, the control unit of the height measuring device 102 controls the sliding plate 106 so that the laser beam is irradiated from the measuring unit 114 to the points corresponding to the points 1b-1 whose height was measured in the first measurement step (S1). The position of the table 108 is adjusted by controlling the operation of the sliding mechanism connected to the table 108.

Specifically, in the second measurement step (S3), as described above, the height is measured in the first measurement step (S1) with the notch 1c of the wafer 1 arranged at a predetermined position on the support surface 108a. The table 108 is moved so that the laser beam is irradiated to the same coordinates as the coordinates in the AB coordinate plane in which the above is performed.

Alternatively, as described above, the relative positional relationship between the coordinates in the AB coordinate plane to which the laser beam is irradiated and the coordinates in the AB coordinate plane of the notch 1c coincides with this relative positional relationship in the first measurement step (S1). The table 108 is moved so as to do so.

Next, the control unit controls the measurement unit 114 to irradiate the corresponding portion with a laser beam from the measurement unit 114. Then, when the reflected laser beam is detected in the measuring unit 114, the control unit calculates the height of the corresponding portion.

When the heights of a plurality of points on the other surface 1b of the wafer 1 are measured in the first measurement step (S1), the heights of the corresponding plurality of points are also measured in the second measurement step (S2). To measure.

When the second measurement step (S3) is completed, the amount of change in the height of one or more points of the other surface 1b of the wafer 1 changed by forming the protective member 5'on one surface 1a of the wafer 1. Calculate (change amount calculation step: S4). Specifically, the height of one or more points measured in the first measurement step (S1) and the height of the corresponding points measured in the second measurement step (S3). Calculate the amount of change.

For example, it is assumed that the protective member 5'is formed so as to have a thickness of 100 μm. Here, when the height of the portion 1b-1 located at the center of the other surface 1b of the wafer 1 whose height was measured in the first measurement step (S1) is 1000 μm, the height of the portion 1b-1 is reached. The reference height is 1100 (= 100 + 1000) μm, which can be increased or decreased according to the change in the shape of the wafer 1 accompanying the formation of the protective member 5'.

Specifically, if the height of the location corresponding to the location 1b-1 measured in the second measurement step (S3) is lower than the reference height (for example, if it is 1095 μm), the other side of the wafer 1. A negative value (for example, −5 μm) is calculated as the amount of change in the height of the central portion of the surface 1b. Further, if the height of the portion corresponding to the portion 1b-1 measured in the second measurement step (S3) is higher than the reference height (for example, if it is 1103 μm), the other of the wafer 1. A positive value (for example, +3 μm) is calculated as the amount of change in the height of the central portion of the surface 1b.

When the change amount calculation step (S4) is completed, the rotation shaft 44 and / or the grinding wheel 98 of the holding surface 40a of the chuck table 36 shown in FIG. 4 is subjected to the change amount obtained in the change amount calculation step (S4). The inclination of the rotating shaft 100 of the grinding surface 98a defined by the lower surface of the wafer 1 is adjusted to grind the other surface 1b of the wafer 1 (grinding step: S5).

Specifically, when the amount of change in height is a negative value (for example, when the calculated amount of change in height is -5 μm), the amount of grinding at the point where the height is measured is increased. Also, when the amount of change in height is a positive value (for example, when the calculated amount of change in height is +3 μm), the amount of grinding at the point where the height is measured is reduced. The inclination of the rotating shaft 44 and / or the rotating shaft 100 is adjusted.

FIG. 12 is a partial cross-sectional side view schematically showing a part of the components of the wafer 1 and the grinding apparatus 30 when grinding the other surface 1b of the wafer 1. When grinding the other surface 1b of the wafer 1, as shown in FIG. 12, the wafer 1 is sucked and held by the holding surface 40a of the chuck table 36 via the protective member 5'. At this time, the wafer 1 and the protective member 5'are straightened into a shape whose center is slightly sharp due to the influence of the negative pressure generated on the conical holding surface 40a.

Further, at least one of the inclination of the rotating shaft 44 of the holding surface 40a and the inclination of the rotating shaft 100 of the grinding surface 98a is adjusted according to the amount of change obtained in the change amount calculation step (S4). A specific example of such adjustment will be described with reference to FIG. Note that FIG. 13 is a top view schematically showing the chuck table 36 of the grinding apparatus 30 when grinding the other surface 1b of the wafer 1.

The holding surface 40a of the chuck table 36 has a conical shape. Further, in the grinding apparatus 30, only a part of the holding surface 40a of the chuck table 36 (the part on the left side of the holding surface 40a shown in FIG. 13) faces the grinding wheel 98.

Therefore, when the bus line included in the part of the holding surface 40a and the grinding surface 98a are parallel to each other, this bus line becomes the portion of the holding surface 40a closest to the grinding surface 98a. For example, when the bus 40b shown by the thin dotted line in FIG. 13 and the grinding surface 98a are parallel to each other, the bus 40b is the portion of the holding surface 40a closest to the grinding surface 98a.

Further, the grinding wheel 98 is discretely arranged along the circumferential direction of the lower surface of the wheel base 96. Therefore, when the bus line included in the part of the holding surface 40a and the grinding surface 98a are parallel to each other, the portion of the holding surface 40a located directly below the portion where the grinding wheel 98 and the other surface 1b of the wafer 1 come into contact with each other. Is an arcuate portion having one end of the generatrix as a start point and the other end as an end point.

For example, when the bus 40b shown in FIGS. 12 and 13 and the grinding surface 98a are parallel to each other, an arcuate shape having one end of the bus 40b located at the apex of the holding surface 40a as the start point and the other end as the end point. The portion 40c is a portion located directly below the portion where the grinding wheel 98 and the other surface 1b of the wafer 1 come into contact with each other.

Here, assuming that the amount of change in the central portion of the other surface 1b of the wafer 1 calculated in the change amount calculation step (S4) is a negative value (for example, −5 μm), the central portion of the other surface 1b. Needs to be ground more than the rest.

In this case, the central portion of the holding surface 40a is made relatively higher than the outer peripheral portion of the holding surface. For example, by operating the pulse motor 64 of the second movable support mechanism 54c to rotate the support column 56 in one direction, the upper support 58 of the second movable support mechanism 54c is raised.

As a result, the inclination of the rotation shaft 44 (FIG. 12) of the holding surface 40a changes so that one end of the bus 40b located at the apex of the holding surface 40a shown in FIG. 13 is closer to the grinding surface 98a than the other end. When the other surface 1b of the wafer 1 is ground in this state, the amount of grinding in the central portion of the other surface 1b of the wafer 1 becomes larger than the amount of grinding in the outer peripheral portion.

Further, in the change amount calculation step (S4), the change amount of the height of the portion located at the center of the other surface 1b of the wafer 1 is 0 μm, and the change in the height of the portion located at the outer peripheral portion is 0 μm. If the amount is a negative value (eg, −5 μm), it is necessary to grind the outer peripheral portion of the other surface 1b more than the central portion.

In this case, the outer peripheral portion of the holding surface 40a is made relatively higher than the central portion. For example, by operating the pulse motor 64 of the second movable support mechanism 54c to rotate the support column 56 in the other direction, the upper support 58 of the second movable support mechanism 54c is lowered.

As a result, the inclination of the rotation shaft 44 (FIG. 12) of the holding surface 40a changes so that the other end of the bus 40b located on the outer periphery of the holding surface 40a shown in FIG. 13 is closer to the grinding surface 98a than one end. When the other surface 1b of the wafer 1 is ground in this state, the amount of grinding on the outer peripheral portion of the other surface 1b of the wafer 1 becomes larger than the amount of grinding on the central portion.

Further, in the change amount calculation step (S4), the change amount of the heights of the two locations located at the central portion and the outer peripheral portion of the other surface 1b of the wafer 1 is 0 μm, and the center thereof. Assuming that the amount of change in the height of the portion located between the portion and the outer peripheral portion is a negative value (for example, -5 μm), the intermediate portion of the other surface 1b is the central portion and the outer peripheral portion. Need to grind more.

In this case, the intermediate portion of the holding surface 40a is made relatively higher than the central portion and the outer peripheral portion. For example, by operating the pulse motor 64 of the first movable support mechanism 54b and the second movable support mechanism 54c to rotate the support column 56 in one direction, the upper support of the first movable support mechanism 54b and the second movable support mechanism 54c Raise 58 to the same extent. As a result, half of the holding surface 40a shown in FIG. 13 (lower half of the holding surface 40a shown in FIG. 14) is closer to the grinding surface 98a than the other half (upper half of the holding surface 40a shown in FIG. 14). The inclination of the rotation shaft 44 of the holding surface 40a changes so as to do so.

Further, the pulse motor 64 of the first movable support mechanism 54b is operated to rotate the support column 56 in one direction, thereby raising the upper support 58 of the first movable support mechanism 54b. As a result, a part of the holding surface 40a shown in FIG. 13 (a fan-shaped portion having a central angle of 120 ° with the portion of the holding surface 40a shown in FIG. 14 overlapping with the first movable support mechanism 54b as the center of the arc). ) Changes the inclination of the rotation shaft 44 (FIG. 12) of the holding surface 40a so as to be closer to the grinding surface 98a than the other portions.

When the inclination of the rotation shaft 44 of the holding surface 40a is controlled by using the inclination adjusting unit 54, the amount of fluctuation in the region close to the outer periphery of the holding surface 40a is larger than the amount of fluctuation in the region close to the center. Therefore, when the other surface 1b of the wafer 1 is ground in this state, the amount of grinding in the intermediate portion of the other surface 1b of the wafer 1 becomes larger than the amount of grinding in the central portion and the outer edge portion.

In the grinding step (S5), the rotation shaft of the holding surface 40a is changed according to the amount of change in the height of one or more of the other surfaces 1b of the wafer 1 obtained in the change amount calculation step (S4). The tilt of 44 is adjusted.

Thereby, the other surface 1b of the wafer 1 can be ground so as to cancel the influence on the shape of the wafer 1 due to the formation of the protective member 5'. As a result, it is possible to provide a wafer 1 in which the other surface 1b becomes flat after the protective member 5'is peeled off from one surface 1a.

In the above-mentioned grinding step (S5), an example of grinding the other surface 1b of the wafer 1 by adjusting only the inclination of the rotating shaft 44 of the holding surface 40a is shown, but in the grinding step of the present invention, the grinding surface is shown. Only the inclination of the rotating shaft 100 of 98a may be adjusted to grind the other surface 1b of the wafer 1. Alternatively, in the grinding step of the present invention, both the inclination of the rotating shaft 44 of the holding surface 40a and the inclination of the rotating shaft 100 of the grinding surface 98a may be adjusted to grind the other surface 1b of the wafer 1.

Further, in the present invention, after grinding the other surface 1b of the wafer 1, the one surface 1a of the wafer 1 may be ground by using the grinding device 30. FIG. 14 is a flowchart schematically showing another example of such a processing method of the wafer 1.

In the processing method shown in FIG. 14, after the grinding step (S5), the protective member 5'is peeled from one surface 1a of the wafer 1 (peeling step: S6). The method of peeling the protective member 5'is not limited to a specific method. The protective member 5'may be mechanically peeled off by using some kind of peeling device after heating the protective member 5', for example. Alternatively, the protective member 5'may be chemically peeled off by dissolving the protective member 5'with some solvent.

When the peeling step (S6) is completed, one surface 1a of the wafer 1 is ground using the grinding device 30 (second grinding step: S7). This grinding is performed in a state where the other surface 1b of the wafer 1 is suction-held by the holding surface 40a of the chuck table 36.

As described above, the other surface 1b of the wafer 1 becomes flat after the protective member 5'is peeled off. Therefore, the grinding of one surface 1a of the wafer 1 may be performed so that the entire surface 1a is uniformly ground. Specifically, the inclination of the rotation shaft 44 of the holding surface 40a may be adjusted so that the generatrix 40b of the holding surface 40a and the grinding surface 98a shown in FIG. 13 are parallel to each other.

In the second grinding step (S7) described above, an example of grinding one surface 1a of the wafer 1 by adjusting only the inclination of the rotating shaft 44 of the holding surface 40a is shown, but the second grinding step of the present invention is shown. In, only the inclination of the rotating shaft 100 of the grinding surface 98a may be adjusted to grind one surface 1a of the wafer 1. Alternatively, in the second grinding step of the present invention, both the inclination of the rotating shaft 44 of the holding surface 40a and the inclination of the rotating shaft 100 of the grinding surface 98a may be adjusted to grind one surface 1b of the wafer 1. ..

Further, in the wafer processing method of the present invention, the peeling step (S6) described above is omitted, and in the second grinding step (S7), the protective member 5'is removed and one surface 1a of the wafer 1 is continuously ground. You may go to.

In this case, it is preferable in that the wafer processing method is simplified. However, in this case, the protective member 5'is removed and the wafer 1 is ground using the same type of grinding wheel 98. Therefore, there is a possibility that the protective member 5'is removed and the wafer 1 is ground by using a grinding wheel 98 of a type unsuitable for removing the protective member 5'or grinding the wafer 1.

On the other hand, when the peeling step (S6) and the second grinding step (S7) are performed separately, it is possible to remove the protective member 5'and grind the wafer 1 by using a method suitable for these. Is preferable.

In addition, the structures and methods according to the above-described embodiments and modifications can be appropriately modified and carried out as long as they do not deviate from the scope of the object of the present invention.

1: Wafer 1a: One surface 1b: The other surface 1b-1: Location 1c: Notch 3: Film 5: UV curable resin 5': Protective member 2: Protective member forming device 4: Base 6: Stage 8: Light source 10: Shutter 12: Filter 14: Exhaust pipe 16: Support structure 16a: Pillar part 16b: Eave part 18: Pressing mechanism 20: Main rod 22: Sub rod 24: Pressing plate 30: Grinding device 32: Base 32a: Opening 34 : X-axis direction movement mechanism 34a: Table cover 36: Chuck table 38: Frame 40: Porous plate 40a: Holding surface 40b: Bus 40c: Arc-shaped part 42: Spindle 44: Rotating shaft 46: Bearing 48: Support plate 50 : Table base 52: Load detection unit 52a: Load measuring device 54: Tilt adjustment unit 54a: Fixed support mechanism 54b: First movable support mechanism 54c: Second movable support mechanism 56: Support column 58: Upper support 60: Bearing 62: Support plate 64: Pulse motor 66: Dust-proof and drip-proof cover 68: Operation panel 70: Support structure 72: Z-axis direction movement mechanism 74: Z-axis guide rail 76: Z-axis movement plate 78: Z-axis ball screw 80: Z-axis pulse motor 82: Support 84: Grinding unit 86: Spindle housing 88: Spindle 90: Servo motor 92: Wheel mount 94: Grinding wheel 96: Wheel base 98: Grinding grindstone 98a: Grinding surface 100: Rotating shaft 102: Height measuring instrument 104: Base 106: Sliding plate 106a: A-axis sliding plate 106b: B-axis sliding plate 108: Table 108a: Top surface (support surface)
110: Support structure 112: Support arm 114: Measuring unit

Claims (5)

A protective member forming device that cures a liquid ultraviolet curable resin provided on the entire one surface of the wafer to form a protective member, and a conical holding surface of a chuck table holds the wafer via the protective member. A method for processing a wafer using a grinding device that grinds the other surface of the wafer with a grinding wheel to flatten the wafer.
It is possible to measure the height of the table having the support surface and the upper surface of the object to be measured placed on the support surface from the support surface, and is relatively parallel to the support surface with respect to the table. One or more locations on the other side of the wafer, with one side of the wafer in contact with the support surface, using a height measuring instrument with a measuring unit capable of moving in a direction. The first measurement step to measure the height of
Using the protective member forming device, a protective member forming step for forming the protective member and
Using the height measuring instrument, the height of the other surface of the wafer at the point corresponding to the point where the height was measured in the first measuring step while the protective member was in contact with the support surface was measured. The second measurement step to measure and
The wafer changed by forming the protective member with reference to the height of one or more points measured in the first measurement step and the height of the corresponding points measured in the second measurement step. A change amount calculation step for calculating the change amount of the height of one or more points on the other surface of the
With the wafer held by the holding surface via the protective member using the grinding device, the height of one or more points of the other surface of the wafer obtained in the change amount calculation step. Depending on the amount of change, the inclination of the rotation axis of the holding surface and the lower surface of the grinding wheel are defined so that the other surface of the wafer becomes flat when the protective member is removed from one surface of the wafer. A grinding step in which the other surface of the wafer is ground with the grinding wheel by adjusting at least one of the inclination of the rotation axis of the grinding surface to be formed.
A method for processing a wafer, which comprises. The grinding step further comprises a second grinding step in which the grinding device is used to grind one surface of the wafer with the grinding wheel while the other surface of the wafer is held by the holding surface.
In the second grinding step, the inclination of the rotation axis of the holding surface and the inclination of the rotation axis of the grinding surface are set so that the bus of the holding surface closest to the grinding surface and the grinding surface are parallel to each other. The method for processing a wafer according to claim 1, wherein at least one is adjusted and ground with the grinding wheel. The wafer processing method according to claim 2, further comprising a peeling step of peeling the protective member from one surface of the wafer between the grinding step and the second grinding step. The location where the height is measured in each of the first measurement step and the second measurement step is characterized by including a location located in the central portion and a location in the outer peripheral portion of the other surface of the wafer. The wafer processing method according to any one of claims 1 to 3. The grinding device comprises a grinding unit to which a grinding wheel having a grinding wheel and an annular wheel base having the grinding wheel arranged in an annular shape on one side thereof is attached.
The chuck table is further provided with a rotation drive source for rotating the holding surface with a straight line passing through the center of the holding surface as a rotation axis, and an inclination adjusting unit for adjusting the inclination of the rotation axis of the holding surface. The wafer processing method according to any one of claims 1 to 4.

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