Grinding apparatus and grinding method

Abstract

This grinding apparatus solves the problem of poor productivity caused by the need to adjust the height of the three support columns that make up the holding mechanism, which is cumbersome, time-consuming, and requires adjustment depending on whether the shape of the wafer grinding surface is finished to a V-shape, flat shape, or valley shape. [Solution] The system includes a rotatable holding means 6 equipped with a holding surface 61 for holding a wafer W, a grinding means 3 rotatably mounted on a grinding wheel 34 having grinding wheels 35 arranged in an annular shape for grinding the wafer W held by the holding means 6, and a grinding water supply means 50 for supplying grinding water L. When grinding the wafer W held by the holding means 6 with the grinding wheels 35, the flow rate of the grinding water L supplied by the grinding water supply means 50 is adjusted to control the shape of the grinding surface of the wafer W.

Description

Technical Field

[0001] The present invention relates to a grinding device for grinding a wafer and a grinding method for grinding a wafer.

Background Art

[0002] A wafer on which a plurality of devices such as ICs and LSIs are formed on the surface is thinned by grinding the back surface by a grinding device, and then divided into individual device chips by a dicing device or a laser processing device, and used in electrical devices such as mobile phones and personal computers.

[0003] The grinding device includes a holding surface for holding a wafer, a rotatable holding means, a grinding means in which a grinding wheel having a grinding stone for grinding the wafer held by the holding means disposed in an annular shape is rotatably mounted, and a grinding water supply means for supplying grinding water, and can finish the wafer to a desired thickness.

[0004] In addition, when grinding the upper surface of the wafer in the grinding device, when finishing the center of the wafer to a slightly mountain shape, a flat shape, or a valley shape, the height of the three struts constituting the holding means for holding the wafer is adjusted to adjust the inclination of the holding surface with respect to the grinding stone constituting the grinding means (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the conventional technology described above, it is necessary to adjust the height of the three support pillars that make up the holding mechanism according to whether the shape of the wafer grinding surface is finished to a V-shape, flat shape, or valley shape. This is cumbersome, time-consuming, and results in poor productivity.

[0007] This invention was obtained as a result of diligent research by the inventors of this invention to solve the above-mentioned problems. The main technical problem is to provide a grinding apparatus and grinding method that can solve the problem of poor productivity, which is caused by the need to adjust the height of the three support pillars that constitute the holding means according to whether the shape of the grinding surface of the wafer is finished to a V-shape, flat shape, or valley shape. [Means for solving the problem]

[0008] To solve the above-mentioned main technical problems, the present invention provides a grinding apparatus for grinding wafers, comprising: a rotatable holding means having a holding surface for holding wafers; a grinding means rotatably mounted on a grinding wheel having grinding wheels arranged in an annular shape for grinding the wafer held by the holding means; and a grinding water supply means for supplying grinding water, wherein when grinding the wafer held by the holding means with the grinding wheels, the grinding apparatus controls the shape of the grinding surface of the wafer by adjusting the flow rate of the grinding water supplied by the grinding water supply means.

[0009] It is preferable to have a first flow rate at which the center of the wafer grinding surface becomes mountain-shaped, a second flow rate at which the wafer grinding surface becomes flat, and a third flow rate at which the center of the wafer grinding surface becomes valley-shaped, and to control the flow rate of the grinding water as appropriate.

[0010] Furthermore, the present invention provides a grinding method for grinding a wafer, comprising: a holding step of holding the wafer in a holding means that is rotatable and capable of holding the wafer; a grinding step of grinding the wafer held in the holding means with a grinding means on which a grinding wheel, on which grinding wheels are arranged in an annular shape, is rotatably mounted; and a grinding water supply step of supplying grinding water to the wafer and the grinding wheel in the grinding step, wherein the grinding water supply step controls the shape of the grinding surface of the wafer by adjusting the flow rate of the supplied grinding water.

[0011] In the grinding water supply process, it is preferable to have a first flow rate that causes the center of the wafer grinding surface to have a peak shape, a second flow rate that causes the wafer grinding surface to have a flat shape, and a third flow rate that causes the center of the wafer grinding surface to have a valley shape, and to control the flow rate of the grinding water as appropriate. [Effects of the Invention]

[0012] The grinding apparatus of the present invention includes a rotatable holding means having a holding surface for holding a wafer, a grinding means rotatably mounted on a grinding wheel having grinding wheels arranged in an annular shape for grinding the wafer held by the holding means, and a grinding water supply means for supplying grinding water. When grinding the wafer held by the holding means with the grinding wheels, the flow rate of the grinding water supplied by the grinding water supply means is adjusted to control the shape of the grinding surface of the wafer. Therefore, when finishing the center of the wafer into a slight peak shape, a flat shape, or a valley shape, it is only necessary to adjust the flow rate of the grinding water, eliminating the need to adjust the height of the three support columns constituting the holding means to adjust the inclination of the holding surface. This eliminates the cumbersome and time-consuming process of such adjustment, thus resolving the problem of poor productivity.

[0013] Furthermore, the grinding method of the present invention includes a holding step of holding a wafer in a holding means that is rotatable and capable of holding the wafer, a grinding step of grinding the wafer with a grinding wheel, on which grinding wheels are arranged in an annular shape and rotatably mounted, a grinding means for grinding the wafer held in the holding means, and a grinding water supply step of supplying grinding water to the wafer and the grinding wheel during the grinding step. In the grinding water supply step, the flow rate of the supplied grinding water is adjusted to control the shape of the grinding surface of the wafer. Therefore, when finishing the center of the wafer into a slight peak shape, a flat shape, or a valley shape, it is only necessary to adjust the flow rate of the grinding water, eliminating the need to adjust the height of the three support pillars constituting the holding means to adjust the inclination of the holding surface, thus resolving the problem of cumbersome and time-consuming adjustments and poor productivity. [Brief explanation of the drawing]

[0014] [Figure 1] This is an overall perspective view of the grinding apparatus of this embodiment. [Figure 2] This is a partially enlarged cross-sectional view of a rough grinding unit installed in the grinding apparatus shown in Figure 1. [Figure 3] This is a perspective view of the wafer and protective tape processed by the grinding method of this embodiment. [Figure 4] This is a perspective view showing an embodiment of the holding process of this embodiment. [Figure 5] This is a perspective view showing embodiments of the grinding process and the grinding water supply process of this embodiment. [Figure 6] This is a conceptual diagram of a control means that stores information about the first flow rate, second flow rate, and third flow rate of grinding water supplied in the grinding water supply process of this embodiment, as well as information about the shape of the wafer grinding surface formed by each flow rate. [Modes for carrying out the invention]

[0015] Hereinafter, embodiments relating to a grinding apparatus configured according to the present invention and a grinding method implemented according to the present invention will be described in detail with reference to the attached drawings.

[0016] FIG. 1 shows a grinding apparatus 1 of the present embodiment. The grinding apparatus 1 includes a holding means 6 configured to be rotatable and having a holding surface 61 for sucking and holding a wafer W, a rough grinding unit 3 as a grinding means for grinding the wafer W held by the holding means 6, and a finish grinding unit 4. The holding means 6 includes a holding surface 61 for sucking and holding the wafer W, which is a workpiece, and a frame body 62 surrounding the holding surface 61. The rough grinding unit 3 is a rough grinding means for rough grinding the back surface of the wafer W, and the finish grinding unit 4 is a finish grinding means for finish grinding the back surface of the wafer W rough-grinded by the rough grinding unit 3. Note that the illustrated grinding apparatus 1 includes three holding means 6 and two grinding means (rough grinding unit 3 and finish grinding unit 4), but the grinding apparatus of the present invention is not limited to the grinding apparatus 1 shown in FIG. 1. For example, it may be a grinding apparatus including only one holding means and one grinding means.

[0017] The grinding apparatus 1 shown in FIG. 1 includes a substantially rectangular parallelepiped apparatus housing 2. In FIG. 1, a support wall 21 is erected on the rear end side of the apparatus housing 2. On the inner surface of this support wall 21, two pairs of guide rails 22, 22 and 23, 23 extending in the vertical direction (Z-axis direction) are provided. The rough grinding unit 3 is mounted on one pair of guide rails 22, 22 so as to be movable in the vertical direction, and the finish grinding unit 4 is mounted on the other pair of guide rails 23, 23 so as to be movable in the vertical direction.

[0018] The rough grinding unit 3 includes a unit housing 31, a wheel mount 33 disposed at the lower end of a rotary shaft 32 rotatably supported by the unit housing 31, a rough grinding wheel 34 mounted on the wheel mount 33 and having a plurality of grinding wheels 35 annularly arranged on the lower surface side, an electric motor 36 mounted on the upper end of the unit housing 31 for rotating the wheel mount 33 in the direction indicated by an arrow R1, and a moving base 38 for supporting the unit housing 31 via a support member 37.

[0019] The movable base 38 is provided with guide grooves that slidably engage with the guide rails 22, 22 provided on the support wall 21 described above. The illustrated grinding device 1 includes a grinding feed mechanism 39 which is provided as a lifting means for raising and lowering the movable base 38 of the rough grinding unit 3 along the guide rails 22, 22. The grinding feed mechanism 39 includes a pulse motor 391, a male screw rod 392 which is disposed on the support wall 21 in the vertical direction parallel to the guide rails 22, 22 and is rotationally driven by the pulse motor 391, and a female screw block (not shown) which is attached to the movable base 38 and screws into the male screw rod 392. The pulse motor 391 drives the male screw rod 392 in the forward and reverse directions, thereby moving the rough grinding unit 3 in the vertical direction.

[0020] The finishing grinding unit 4 is configured in substantially the same way as the rough grinding unit 3 described above, and comprises a unit housing 41, a wheel mount 43 disposed at the lower end of a rotating shaft 42 rotatably supported by the unit housing 41, a finishing grinding wheel 44 mounted on the wheel mount 43 with multiple grinding wheels 45 arranged in an annular pattern on its lower surface, an electric motor 46 mounted at the upper end of the unit housing 41 that rotates the wheel mount 43 in the direction indicated by arrow R2, and a movable base 48 that supports the unit housing 41 via a support member 47. The grinding wheels 45 disposed in the finishing grinding unit 4 are made of finer abrasive grains compared to the grinding wheels 35 disposed in the rough grinding unit 3 described above.

[0021] The moving base 48 is provided with guiding grooves which are slidably engaged with the guiding rails 23, 23 provided on the above-described supporting wall 21. The grinding device 1 in the illustrated embodiment includes a grinding feed mechanism 49 disposed as lifting means for lifting and lowering the moving base 48 of the finish grinding unit 4 along the guiding rails 23, 23. The grinding feed mechanism 49 includes a pulse motor 491, a male screw rod 492 disposed in the vertical direction parallel to the guiding rails 23, 23 on the supporting wall 21 and rotationally driven by the pulse motor 491, and a female screw block (not shown) attached to the moving base 48 and screwed with the male screw rod 492. By driving the male screw rod 492 forward and backward by the pulse motor 491, the finish grinding unit 4 is moved in the vertical direction.

[0022] The upper ends 32a of the rotary shafts 32 rotated by the electric motors 36 of the rough grinding units 3 and the upper ends 42a of the rotary shafts 42 rotated by the electric motors 46 of the finish grinding units 4 are connected to grinding water supply means 50 for supplying grinding water L. The grinding water supply means 50 includes a grinding water source 52, a grinding water path 54 for supplying the grinding water L from the grinding water source 52, a branch path 56a branched from the grinding water path 54 and connected to the upper end 42a of the rotary shaft 42, a branch path 56b branched from the grinding water path 54 and connected to the upper end 32a of the rotary shaft 32, an on-off valve 58a disposed in the branch path 56a, and an on-off valve 58b disposed in the branch path 56b. The on-off valves 58a, 58b are connected to control means 100, and their opening degrees are controlled based on control signals transmitted from the control means 100.

[0023] As shown in Figure 2, the grinding fluid L supplied from the upper end 32a of the rotating shaft 32 is supplied to the lower side of the grinding wheel 34 through the internal passage 32b passing through the rotating shaft 32 and the wheel mount 33, and through the connecting passage 34a of the grinding wheel 34. On the lower side of the grinding wheel 34, it is sprayed radially outward toward the area where the grinding wheel 35 is located, and supplied to the grinding area of ​​the wafer W held by the holding means 6 of the grinding wheel 35. Although not shown in the illustration, the finish grinding unit 4 has a similar configuration. Grinding fluid L supplied from the upper end 42a of the rotating shaft 42 is supplied to the lower side of the grinding wheel 44 via internal passages (not shown) of the rotating shaft 42 and wheel mount 43, and connecting passages (not shown) of the grinding wheel 44. On the lower side of the grinding wheel 44, it is sprayed radially outward towards where the grinding wheel 45 is located and supplied to the grinding area of ​​the wafer W held by the holding means 6 of the grinding wheel 45.

[0024] Returning to Figure 1 and continuing the explanation, the grinding device 1 is equipped with a turntable 5 positioned in front of the support wall 21 so as to be substantially flush with the upper surface of the device housing 2. This turntable 5 is formed in a relatively large diameter disc shape and is rotated as appropriate in the direction indicated by arrow R3 by a rotational drive mechanism (not shown) within the drain pan 20 on the upper surface of the device housing 2. Three of the above-mentioned holding means 6 are provided on the turntable 5, each at an angle of 120 degrees. Each holding means 6 is equipped with a rotational drive mechanism (not shown) and is configured to be rotatable in the direction indicated by arrow R4.

[0025] The three holding means 6 arranged on the turntable 5 are moved sequentially from the workpiece loading / unloading area A → rough grinding area B → finish grinding area C → workpiece loading / unloading area A as the turntable 5 is rotated in the direction indicated by arrow R3. Near the workpiece loading / unloading area A in the drain pan 20, a washing water supply nozzle 17 is provided to supply washing water (which can be used in conjunction with the grinding water L supplied from the grinding water source 52 mentioned above) to the holding surface 61 of the holding means 6 positioned in the workpiece loading / unloading area A.

[0026] The illustrated grinding apparatus 1 includes a first cassette 7 located on one side of the workpiece loading / unloading area A and accommodating multiple wafers W, which are workpieces before grinding; a second cassette 8 located on the other side of the workpiece loading / unloading area A and accommodating multiple wafers W after grinding; a temporary placement table 9 located between the first cassette 7 and the workpiece loading / unloading area A for centering the wafers W; a cleaning means 11 located between the workpiece loading / unloading area A and the second cassette 8; and the first cassette... The apparatus includes a workpiece loading / unloading means 12 that loads the wafer W stored in the tor 7 onto the temporary storage table 9 and loads the wafer W, which has been washed by the cleaning means 11, into the second cassette 8; a first transport means 13 that transports the unprocessed wafer W held on the temporary storage table 9 onto the holding means 6 located in the workpiece loading / unloading area A; and a second transport means 14 that transports the ground wafer W placed on the holding means 6 located in the workpiece loading / unloading area A to the cleaning means 11. In this embodiment, the holding surface 61 of the holding means 6 is arranged parallel to the grinding wheel 35 arranged in an annular shape on the lower surface of the grinding wheel 34 of the rough grinding unit 3 and the grinding wheel 45 arranged in an annular shape on the lower surface of the grinding wheel 44 of the finish grinding unit 4.

[0027] The grinding apparatus 1 is not limited to a configuration comprising the first transport means 13 and the second transport means 14 described above, but may also be equipped with a single transport means that serves as both the first transport means 13 and the second transport means 14. That is, the single transport means may transport the unprocessed wafer W from the temporary storage table 9 to the holding means 6 located in the workpiece loading / unloading area A, and the ground wafer W from the holding means 6 located in the workpiece loading / unloading area A to the cleaning means 11.

[0028] The control means 100 includes a central processing unit (CPU) that executes calculation processing according to a control program, a read-only memory (ROM) that stores the control program and the like, a read-write random access memory (RAM) that serves as a storage means for storing calculation results and the like, and an input interface and an output interface (none of which are shown in the illustration). The control means 100 configured in this way controls each operating part of the grinding apparatus 1, including the on-off valves 58a and 58b.

[0029] The grinding apparatus 1 of this embodiment has a configuration that is generally as described above, and the grinding method of this embodiment, which is carried out based on the present invention, will be described below.

[0030] (holding process) When carrying out the grinding method for grinding wafers according to this embodiment, a wafer W as shown in Figure 3 is prepared as the workpiece. The wafer W is, for example, a silicon wafer, and multiple devices D are formed on the surface Wa, partitioned by lines to be divided. Protective tape T is attached to the surface Wa of the wafer W to protect the devices D on the surface Wa side when grinding the back surface Wb, which is the grinding surface of the wafer W. Multiple such wafers W are stored in the first cassette 7 described above and transported to the grinding apparatus 1.

[0031] The wafer W, which is contained in the first cassette 7 and loaded, is unloaded from the first cassette 7 by the workpiece loading / unloading means 12. Next, the wafer W is placed on the temporary placement table 9 with its back surface Wb facing upwards and centered, then it is picked up by the first transport means 13 and transported to the holding means 6 located in the workpiece loading / unloading area A. Then, as shown in Figure 4, the wafer W is placed on the holding surface 61 with its back surface Wb facing upwards, and a suction means (not shown) is activated to generate negative pressure on the holding surface 61 and hold it in place. This completes the holding process of this embodiment.

[0032] (Grinding process) Once the holding process described above has been performed, a grinding process is carried out on the back surface Wb of the wafer W held by the holding means 6, including grinding by the rough grinding unit 3 and the finish grinding unit 4 described above, which are grinding means.

[0033] When performing the grinding process, the turntable 5 of the grinding apparatus 1, as described with reference to Figure 1, is rotated in the direction indicated by arrow R3, and the holding means 6, which holds the wafer W in the holding process described above, is positioned directly below the rough grinding unit 3, i.e., in the rough grinding area B. Next, as shown in Figure 5, the rotation axis 32 of the rough grinding unit 3 is rotated at, for example, 2500 rpm in the direction indicated by arrow R1 in Figure 5, while the holding means 6 is rotated at, for example, 200 rpm in the direction indicated by arrow R4 in the figure. Then, the grinding feed mechanism 39 of the rough grinding unit 3 is activated to lower the rough grinding unit 3 in the direction indicated by arrow R5 in the figure, bringing the multiple annularly arranged grinding wheels 35 into contact with the back surface Wb, and the grinding wheel 33 is fed at, for example, a grinding feed speed of 0.5 μm / second to grind the back surface Wb of the wafer W. At this time, the outer edges of the multiple grinding wheels 35 arranged in a ring shape are positioned to pass through the center P of the wafer W.

[0034] (Grinding water supply process) In the grinding process described above, when rough grinding is performed on the back surface Wb of the wafer W, the opening degree of the on-off valve 58b of the grinding water supply means 50 is controlled by the control means 100, and a quantity of grinding water L corresponding to the opening degree of the on-off valve 58b is supplied to the grinding area of ​​the wafer W by the rough grinding unit 3 via the grinding water path 54, branch path 56b, and rotating shaft 32 connected to the grinding water source 52.

[0035] Here, the appropriate memory in the control means 100 that stores the grinding conditions stores information obtained in advance through experiments, more specifically, information on the thickness (vertical axis: μm) at a predetermined distance (horizontal axis: mm) from the center of the wafer W when the amount of grinding water L supplied to the rough grinding unit 3 by the grinding water supply means 50 is changed while performing grinding on the back surface Wb of the wafer W for a predetermined time under the above-described grinding conditions.

[0036] Figure 6 shows an example of the thickness information described above, which is stored in the appropriate memory of the control means 100. For example, when grinding is performed on the back surface Wb, which is the grinding surface, by the rough grinding unit 3 while supplying grinding water L at the first flow rate (e.g., 7 L / min) shown in the upper section 110a, the grinding surface of the wafer W will have a mountain shape, as shown by the curve Q1 in the figure, where the center of the grinding surface of the wafer W is thicker and it gets thinner towards the outer edge. Also, when grinding is performed on the back surface Wb, which is the grinding surface, by the rough grinding unit 3 while supplying grinding water L at the second flow rate (e.g., 5 L / min) shown in the middle section 110b, the grinding surface of the wafer W will have a flat shape, as shown by the curve Q2 in the figure, where the center of the grinding surface of the wafer W and the outer edge are approximately the same thickness. Furthermore, when grinding is performed on the back surface Wb, which is the grinding surface, by the rough grinding unit 3 while supplying grinding water L at a third flow rate (for example, 1.8 L / min) as shown in the lower section 110c, the grinding surface of the wafer W is processed to have a valley shape, as shown by the curve Q3 in the figure, where the thickness is thinner in the center of the grinding surface of the wafer W and becomes thicker towards the outer edge. It is presumed that the tendency shown by these curves Q1 to Q3 is due to the fact that, for example, as the amount of grinding water L supplied by the grinding water supply means 50 increases, a large amount of grinding water L flows between the central region of the back surface Wb of the wafer W and the grinding wheel 35, so that the central region of the wafer W is cooled more, thermal expansion associated with grinding is suppressed and the amount of grinding in the central region is reduced, and conversely, as the amount of grinding water L supplied decreases, the amount of grinding in the central region increases.

[0037] As described above, based on the appropriate information stored in the memory of the control means 100 and the shape of the grinding surface of the wafer W desired by the operator, the amount of grinding water L supplied in the grinding water supply process performed during grinding by the rough grinding unit 3 described above is determined, and the determined amount of grinding water supplied is input to and stored in the control means 100.

[0038] For example, if a polishing process is planned after the grinding process, and the outer peripheral region of the wafer W tends to be polished more than the central region during the polishing process, the on-off valve 58b of the grinding water supply means 50 is controlled in the grinding water supply process, which is performed together with the grinding process, so that the flow rate of the grinding water L supplied in the grinding water supply process becomes a third flow rate (1.8 L / min) in order to create a so-called valley shape in which the central region of the wafer W is thin and the outer peripheral region is thick. At the same time, grinding can be carried out while measuring the thickness of the wafer W using a contact-type or non-contact-type measuring gauge (not shown), and the rough grinding is completed with the ground surface of the wafer W having the desired shape for the rough grinding. When measuring the thickness of the wafer W, the thickness of the central region and the outer peripheral region on the back surface Wb of the wafer W may be measured as needed.

[0039] As described above, the grinding process and grinding water supply process by the rough grinding unit 3 make it possible to shape the grinding surface of the wafer W into a desired shape (a valley shape in the above embodiment).

[0040] As described above, once the rough grinding of the wafer W by the rough grinding unit 3 is completed, the turntable 5 is rotated in the direction indicated by R3 to move the holding means 6, which has finished rough grinding, directly below the finish grinding unit 4, i.e., to the finish grinding area C. The holding means 6 is moved to the finish grinding area C. Next, the rotation axis 42 of the finish grinding unit 4 is rotated at, for example, 2500 rpm, while the holding means 6 is rotated at, for example, 200 rpm. Then, the grinding feed mechanism 49 is activated to bring the grinding wheel 45 into contact with the back surface Wb of the wafer W, and the grinding wheel 44 is fed downward, i.e., perpendicular to the holding means 6, at, for example, a grinding feed speed of 0.1 μm / second. At this time, the grinding water supply means 50 is activated to open the on / off valve 58a, and grinding water L is supplied from the lower surface of the finishing grinding wheel 44 to the back surface Wb, which is the grinding surface of the wafer W, via the rotation axis 42.

[0041] In this embodiment, the grinding water L supplied during finish grinding by the finish grinding unit 4 is 1.8 L / min. Simultaneously, grinding can be carried out while measuring the thickness of the wafer W using a contact-type or non-contact-type measuring gauge (not shown). Finish grinding is completed while maintaining the shape of the ground surface obtained by the rough grinding by the rough grinding unit 3, thus completing the grinding process consisting of the rough grinding and this finish grinding. In addition, during finish grinding by the finish grinding unit 4, the supply amount of grinding water L by the grinding water supply means 50 can be adjusted to appropriately control the shape of the ground surface of the wafer W being ground during finish grinding.

[0042] The amount of grinding water L supplied in the grinding water supply process, which is stored in the control means 100, is not limited to the three flow rates described above: the first, second, and third flow rates. For example, the shape of the grinding surface of the wafer W formed based on intermediate flow rates between the first and second flow rates, and intermediate flow rates between the second and third flow rates, may be confirmed experimentally, and the experimental results may be stored in the control means 100 and used to determine the amount of grinding water L supplied in the grinding water supply process.

[0043] Furthermore, in the above-described embodiment, the amount of grinding water L supplied was adjusted to control the shape of the grinding surface of the wafer W to a desired shape through rough grinding performed by the rough grinding unit 3, and the shape of the grinding surface formed by rough grinding was maintained during finish grinding. However, the present invention is not limited thereto. For example, during rough grinding by the rough grinding unit 3, the amount of grinding water L supplied may be adjusted to make the grinding surface of the wafer W flat (5 L / min), and during finish grinding by the finish grinding unit 4, the amount of grinding water L supplied may be selected to make a desired shape, such as a mountain shape (7 L / min), thereby controlling the shape of the grinding surface of the wafer W.

[0044] Furthermore, in the above-described embodiment, the information regarding the first flow rate, second flow rate, and third flow rate stored in the control means 100 was shared between the rough grinding unit 3 and the finish grinding unit 4, but the present invention is not limited thereto. For example, information regarding the amount of grinding water L supplied corresponding to the shape of the grinding surface may be separately determined for the rough grinding unit 3 and the finish grinding unit 4 by experiments conducted in advance, and the separately determined flow rate values ​​may be used in the rough grinding and finish grinding processes.

[0045] As described above, the grinding method of this embodiment is carried out, and the ground surface of the wafer W is formed into a desired shape. However, the present invention is not limited to making the thickness of the wafer W mountain-shaped with a first flow rate, flat with a second flow rate, and valley-shaped with a third flow rate, as in the embodiment described above. For example, the shape of the ground surface of the wafer W obtained by grinding in the grinding process may be affected by the thickness of the protective tape T, etc. And, for example, if the grinding process is carried out while supplying grinding water L by selecting a second flow rate (5 L / min) in the grinding water supply process and controlling the on-off valve 58b in order to flatten the thickness of the wafer W in the grinding process, the wafer W may not be ground into a mountain shape instead of the expected flat shape. In that case, the shape of the wafer W can be controlled to the desired flat shape by adjusting the flow rate of grinding water L to be less than the second flow rate (5 L / min) and carrying out the grinding process and the grinding water supply process.

[0046] The inventors of the present invention have found that, with the grinding apparatus and grinding method of the above-described embodiment, when finishing the center of a wafer into a slight peak shape, flat shape, or valley shape, it is only necessary to adjust the flow rate of the grinding water L. This eliminates the need to adjust the height of the three support columns constituting the holding means 6 to adjust the inclination of the holding surface, thus resolving the problem of cumbersome and time-consuming adjustments and poor productivity. [Explanation of Symbols]

[0047] 1: Grinding device 2: Device housing 21:Supporting wall 22: Guide rail 23: Guide rail 3: Rough grinding unit 31: Unit Housing 32: Rotation axis 32a: Upper end 33: Wheel Mount 34: Grinding Wheel 35: Grinding wheel 36: Electric motor 37: Support member 38: Mobile base 39: Grinding feed mechanism 4: Finishing grinding unit 41: Unit Housing 42: Rotation axis 42a:Top end 43: Wheel Mount 44: Grinding Wheel 45: Grinding wheel 46: Electric motor 47: Support member 48: Mobile base 49: Grinding feed mechanism 5: Turntable 6: Holding means 61: Holding surface 62: Frame 7: First cassette 8: Second cassette 9: Temporary placement table 11: Cleaning methods 12: Workpiece loading / unloading means 13: First means of transport 14: Second means of transport 17: Washing water supply nozzle 50: Grinding water supply means 52: Grinding water source 54: Grinding water pathway 56a, 56b: Branching routes 58a, 58b: Shut-off valves 100: Control means

Claims

1. A grinding apparatus for grinding wafers, The system includes a rotatable holding means having a holding surface for holding a wafer, a grinding means rotatably mounted on a grinding wheel having grinding wheels arranged in an annular pattern for grinding the wafer held by the holding means, and a grinding water supply means for supplying grinding water. A grinding apparatus that controls the shape of the grinding surface of a wafer by adjusting the flow rate of grinding water supplied by a grinding water supply means when grinding a wafer held in a holding means with a grinding wheel.

2. A grinding apparatus according to claim 1, comprising a first flow rate that causes the center of the wafer grinding surface to be shaped like a peak, a second flow rate that causes the wafer grinding surface to be shaped like a flat surface, and a third flow rate that causes the center of the wafer grinding surface to be shaped like a valley, wherein the flow rate of the grinding water is controlled as appropriate.

3. A grinding method for grinding wafers, A holding step of holding the wafer in a holding means that is rotatable and holds the wafer, A grinding step in which a wafer is ground using a grinding means that is rotatably mounted on a grinding wheel having grinding wheels arranged in an annular shape for grinding the wafer held by the holding means, The grinding process includes a grinding water supply step of supplying grinding water to the wafer and the grinding wheel, A grinding method in which the flow rate of the supplied grinding water is adjusted during the grinding water supply process to control the shape of the grinding surface of the wafer.

4. The grinding method according to claim 3, wherein the grinding water supply step comprises a first flow rate that causes the center of the wafer grinding surface to have a peak shape, a second flow rate that causes the wafer grinding surface to have a flat shape, and a third flow rate that causes the center of the wafer grinding surface to have a valley shape, and the flow rate of the grinding water is controlled as appropriate.

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