Processing method and cutting device

Abstract

To provide a novel art in edge trimming for cutting an outer peripheral edge of a wafer.SOLUTION: In a processing method in which an outer periphery part Wg of a surface Wa of a wafer W is cut to be trimmed by a cutting blade 21, cutting water 40 is supplied from a cutting water supply nozzle 72a at the side closer to a center Wc of the wafer W than the cutting blade 21 with respect to a cutting point K during cutting toward the side far from the center Wc of the water W.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a processing method and a cutting device for trimming the outer periphery of the front surface of a wafer with a cutting blade. [Background technology]

[0002] Conventionally, as disclosed in, for example, Patent Documents 1 to 3, the outer periphery of a semiconductor wafer is chamfered into an arc shape, and it is known that when the semiconductor wafer is thinned by back-grinding while leaving the chamfered edge portion, a sharp edge is formed on the outer periphery, and when a load or impact is applied to the edge portion, chipping easily occurs and the wafer breaks.

[0003] As a countermeasure to this, a so-called "edge trimming process" is performed in which the outer periphery of the front surface of the wafer is trimmed with a cutting blade, so that sharp edges are not formed when the back surface of the semiconductor wafer is subsequently ground. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-207459 A [Patent Document 2] JP 2003-273053 A [Patent Document 3] JP 2000-173961 A Summary of the Invention [Problem to be solved by the invention]

[0005] In edge trimming, a cutting blade is inserted into the outer edge of the wafer to a specified depth, and cutting water is supplied to the vicinity of the processing point during this cutting process. The main purposes of using cutting water are lubrication, cooling, and cleaning, but focusing on cleaning in particular, cutting chips generated by cutting are removed from the vicinity of the processing point by the cutting water.

[0006] A configuration is known in which cutting water supply nozzles for supplying cutting water are arranged on both sides of the cutting blade in the direction of the rotation axis of the cutting blade, and cutting water is supplied from both sides of the cutting blade simultaneously. This method of supplying cutting water is not limited to edge trimming processing, but is also applicable to dicing processing for dividing a wafer into individual chips.

[0007] Thus, it has been common practice in the past to supply cutting water simultaneously from both sides of the cutting blade in general cutting processes such as edge trimming and dicing.

[0008] However, the inventors took note of the characteristics of edge trimming processing, which involves cutting the outer edge of the wafer, and the situation in which cutting debris (particles) generated during processing remain on the wafer surface, and came to invent an optimal processing method for edge trimming processing.

[0009] In particular, a wafer that is to be edge-trimmed may require high cleanliness of the wafer surface in a subsequent process, for example, when a process of bonding the wafer surface to another wafer is performed after edge-trimming.

[0010] As described above, the present invention proposes a new technique for edge trimming, which cuts the outer peripheral edge of a wafer. [Means for solving the problem]

[0011] The problem to be solved by the present invention has been described above, and the means for solving this problem will now be described.

[0012] According to one aspect of the present invention, there is provided a processing method for cutting and trimming the outer periphery of the surface of a wafer with a cutting blade, in which cutting water is supplied to the processing point during cutting from a cutting water supply nozzle that is closer to the center of the wafer than the cutting blade, toward the side farther from the center of the wafer.

[0013] In addition, according to one aspect of the present invention, in an apparatus configuration that includes a cutting water supply nozzle closer to the center of the wafer than the cutting blade, and a cutting water supply nozzle farther from the center of the wafer than the cutting blade, during cutting, cutting water is supplied to the processing point only from the cutting water supply nozzle closer to the center of the wafer.

[0014] In addition, according to one aspect of the present invention, a cutting device has a cutting water supply nozzle closer to the center of the wafer than the cutting blade, a cutting water supply nozzle farther from the center of the wafer than the cutting blade, a cutting water supply path for supplying cutting water to each of the cutting water supply nozzles, a control valve provided in each of the cutting water supply paths for controlling whether or not cutting water is supplied to each of the cutting water supply nozzles, and a controller for controlling the operation of each of the control valves. Effect of the Invention

[0015] The present invention provides the following advantages. That is, according to one aspect of the present invention, the cutting waste generated by cutting is removed from the inside to the outside of the wafer, and the cutting waste (particles) remaining on the surface of the wafer can be reduced. Also, by forming a flow of cutting water from the inside to the outside of the wafer, the cutting water is less likely to flow toward the inside of the wafer, and the cutting water containing the cutting waste is prevented from moving toward the wafer surface. [Brief description of the drawings]

[0016] [Figure 1] 1 is a perspective view of one embodiment of a cutting device for use in practicing the present invention; [Diagram 2]FIG. 4 is a front view illustrating the configuration of the cutting unit. [Diagram 3] 1A to 1C are diagrams for explaining an outline of edge trimming processing. [Figure 4] FIG. [Diagram 5] A view from the direction of arrow M in FIG. 4. [Figure 6] (A) is a diagram explaining half cut trimming, and (B) is a diagram explaining full cut trimming. [Figure 7] 1A is a diagram showing an image of remaining cutting debris in an embodiment of the present invention, and FIG. 1B is a diagram showing an image of remaining cutting debris in a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view showing one embodiment of a cutting device 2 that can be used to practice the present invention. The cutting device 2 has a base 4, and a holding table 8 is disposed on the base 4 so as to be capable of reciprocating in the X-axis direction by a cutting feed mechanism (X-axis moving mechanism) not shown.

[0018] On the upper surface of the base 4, there are provided a cassette placement section 5a for placing a cassette 5 that contains a wafer W, and a cleaning device 6 for cleaning the workpiece after cutting. Devices are regularly arranged on the surface of the wafer W, and a grid-like division line is set between the devices. The wafer W is to be cut along the division line to be divided into individual chips. Note that the wafer W may not have any devices formed on its surface.

[0019] The wafer W is integrated with an annular frame F via a tape T to form a wafer unit U. The wafer unit U is housed in a cassette 5 and carried onto a holding table 8 by a carrier device (not shown). As will be described in detail later, the wafer unit U is subjected to edge trimming processing in a cutting unit 20, carried to a cleaning device 6 and cleaned, and after cleaning, carried out to the cassette 5.

[0020] A plurality of clamps 9 and a water cover 11 are arranged around the holding table 8, and a bellows 12 is connected between the water cover 11 and the base 4 to protect the cutting feed mechanism located below.

[0021] A gate-shaped column 14 is erected on the base 4, and a pair of guide rails 15 extending in the Y-axis direction are provided on the side of the column 14, a Y-axis moving mechanism 17 consisting of a ball screw 16a and a pulse motor 16b, and a Y-axis moving block 18 are provided, and the Y-axis moving block 18 moves in the Y-axis direction along the guide rails 15 by being driven by the Y-axis moving mechanism 17.

[0022] The Y-axis moving block 18 is provided with a pair of guide rails 19 extending in the Z-axis direction, a Z-axis moving mechanism 32 consisting of a ball screw 31a and a pulse motor 31b, and a Z-axis moving block 30, and the Z-axis moving block 30 moves in the Z-axis direction along the guide rails 19 by being driven by the Z-axis moving mechanism 32.

[0023] The cutting unit 20 is attached to the Z-axis moving block 30. A spindle (not shown) is rotatably accommodated in a spindle housing 36 of the cutting unit 20. A cutting blade 21 is attached to the tip of the spindle. An imaging unit 7 is disposed near the cutting unit 20.

[0024] FIG. 2 is a diagram showing an example of the configuration of the cutting unit 20. As shown in FIG. The cutting unit 20 comprises a spindle housing 22, a spindle 23 that protrudes from the spindle housing 22 and is rotated by a motor not shown, a mount flange 24 attached to the tip of the spindle 23, and a blade cover 70 provided at the tip of the spindle housing 22.

[0025] The cutting unit 20 comprises a mount fixing bolt 25 that fixes the mount flange 24 to the tip of the spindle 23, a cutting blade 21 that is attached to the mount flange 24, and a blade fixing nut 26 which is a fixing device for clamping and fixing the cutting blade 21 between the mount flange 24.

[0026] The mount flange 24 includes a cylindrical boss portion 241 and a flange portion 242 provided at one end of the boss portion 241 on the spindle housing 22 side. The flange portion 242 is formed in an annular shape with a diameter larger than the outer diameter of the boss portion 241, and is formed with an annular end surface 244 for abutting against the rear surface of the cutting blade 21. A male thread 243 is formed on the outer periphery of the other end of the boss portion 241 of the mount flange 24.

[0027] 2 is configured as a so-called hub blade, and includes an annular hub base 212 made of a metal such as an aluminum alloy, and an annular cutting blade 213 formed to surround the outer periphery of the hub base 212. A fitting hole 214 for mounting to a boss portion 241 of the mount flange 24 is provided in the center of the hub base 212. The boss portion 241 of the mount flange 24 is inserted into the fitting hole 214. The cutting blade 213 is made of abrasive grains such as diamond or CBN (Cubic Boron Nitride) and a bond material such as metal or resin, and is formed to a predetermined thickness.

[0028] The cutting blade 21 is fixed to the mount flange 24 by fitting the fitting hole 214 of the hub base 212 into the boss outer peripheral surface 246 of the cylindrical boss portion 241 of the mount flange 24 and fastening the blade fixing nut 26 to the male thread 243 of the boss portion 241. In this state, the cutting blade 21 is sandwiched between the blade fixing nut 26 and the mount flange 24, and the rear surface of the hub base 212 is supported by abutting against the annular end surface 244 formed on the mount flange 24.

[0029] A fixing hole 23a is formed at the tip of the spindle 23 coaxially with the spindle 23. With the mount flange 24 attached to the spindle 23, the mount flange 24 is fixed to the spindle 23 by fastening a mount fixing bolt 25 to the fixing hole 23a.

[0030] 2, the blade cover 70 provided at the tip of the spindle housing 22 has a cover body 71, a cutting water supply nozzle assembly 72, and a nozzle block 73. The cutting water supply nozzle assembly 72 is fixed to a mounting plate 74a that is fixed to the tip of a rod 74 of an air cylinder, and moves to a replacement position away from the cover body 71 when replacing the cutting blade.

[0031] 2, the cutting water supply nozzle assembly 72 is fixed to a mounting plate 74a with a screw 72n. Connectors 72f, 72g to which hoses 82f, 82g are connected are attached to the upper part of the cutting water supply nozzle assembly 72. A pair of cutting water supply nozzles 72a, 72b are connected to the lower part of the cutting water supply nozzle assembly 72. Inside the cutting water supply nozzle assembly 72, flow paths (not shown) are formed that connect the connectors 72f, 72g to the cutting water supply nozzles 72a, 72b, respectively.

[0032] The connectors 72f, 72g are connected to a cutting water supply source 86 via hoses 82f, 82g (cutting water supply paths) and control valves 85f, 85g, respectively. The controller 10 controls the supply of cutting water to each of the connectors 72f, 72g by controlling the opening and closing of the control valves 85f, 85g, thereby making it possible to switch on / off the supply of cutting water from each of the cutting water supply nozzles 72a, 72b.

[0033] The cutting water supply nozzles 72a and 72b are configured with a substantially L-shaped pipe member, and are arranged so that the lower end portion of the cutting blade 21 is located between the horizontal portions of both. The cutting water supply nozzles 72a and 72b also function to cool the cutting blade 21, and are also called blade cooler nozzles. A splash cover 72e is provided so as to surround the outside of the substantially L-shaped bent portion of the cutting water supply nozzles 72a and 72b.

[0034] In the horizontal portions of the cutting water supply nozzles 72a, 72b, at positions facing the cutting blade 21, cutting water ejection ports 72d are provided at a plurality of locations spaced apart in the horizontal direction.

[0035] 5, the cutting water supply nozzle 72a closer to the center Wc of the wafer W than the cutting blade 21 has a cutting water jetting port 72d that opens obliquely downward on the cutting blade 21 side. As a result, the cutting water 40 jetted from the cutting water supply nozzle 72a moves in a direction away from the wafer.

[0036] Similarly, the cutting water jetting port 72d of the cutting water supply nozzle 72b farther from the center Wc of the wafer W than the cutting blade 21 opens obliquely downward on the cutting blade 21 side. As a result, the cutting water (not shown) jetted from the cutting water supply nozzle 72b moves in a direction toward the center Wc of the wafer.

[0037] 2, the nozzle block 73 is provided with a connector 73c to which a hose 84 is connected, and a shower nozzle 73a that supplies cooling water toward the outer periphery of the cutting blade. The connector 73c is connected to a cooling water supply source 87 via the hose 84 and a control valve 84f. The controller 10 controls the supply of cutting water to the connector 73c by controlling the opening and closing of the control valve 84f, thereby making it possible to switch on / off the supply of cooling water from the shower nozzle 73a.

[0038] The cooling water supplied from shower nozzle 73a may be the same as the cutting water supplied from cutting water supply nozzles 72a, 72b or may be different, and shower nozzle 73a may be connected to a cutting water supply source 86.

[0039] 1 configured as above can perform edge trimming, which will be described later, as well as dicing of a wafer thinned by grinding after edge trimming. The cutting device 2 is automatically controlled by a controller 10, which controls, for example, the operation of various operating parts during edge trimming, which will be described later, and the on / off of the cutting water supply.

[0040] Next, an embodiment of the processing method according to the present invention will be described. As shown in the examples of Figures 3 to 6(A) and (B), this embodiment is a processing method in which the outer peripheral portion Wg of the surface Wa of the wafer W is cut and trimmed with a cutting blade 21, and during cutting, cutting water 40 is supplied to the processing point K from a cutting water supply nozzle 72a that is closer to the center Wc of the wafer W than the cutting blade 21 toward the side farther from the center Wc of the wafer W.

[0041] Specifically, as shown in Fig. 3, for example, the cutting blade 21 is positioned above the outer periphery Wg of the wafer W, and the cutting blade 21 is rotated at high speed in the direction of the arrow R1. Next, as shown in Fig. 4, the cutting blade 21 is lowered and cuts to a predetermined cutting depth.

[0042] Here, the cutting depth is set appropriately depending on the cutting method, such as half-cut trim, in which the wafer W is cut halfway in the thickness direction Wz as shown in FIG. 6(A), or full-cut trim, in which the wafer W is cut all the way in the thickness direction Wz as shown in FIG. 6(B).

[0043] 3 to 5, the cutting blade 21 is lowered to start cutting, and the holding table 8 (FIG. 1) is rotated in the direction of arrow L1 (FIG. 3) to rotate the wafer W 360 degrees in a horizontal plane. This causes the outer periphery Wg of the wafer W to be continuously cut, that is, edge trimming along the outer periphery Wg is performed over the entire circumference of the wafer W. FIG. 4 shows that a trimmed portion Wt is formed along the outer periphery Wg by half-cut trimming.

[0044] 4 and 5, during trimming, cutting water 40 is supplied to the processing point K and its periphery only from the cutting water supply nozzle 72a that is closer to the center Wc of the wafer W than the cutting blade 21. The processing point K refers to the location on the wafer W that is cut by the cutting blade 21, and the cutting water 40 is supplied to the range including the processing point K to remove (clean) cutting debris generated at the processing point K, lubricate the gap between the cutting blade and the wafer at the processing point K, and cool the heat generated by cutting.

[0045] In this way, by supplying the cutting water 40 in a direction away from the wafer W (radially outward), the processing point K is cooled and cutting chips 50 generated by cutting are also removed to the outside of the wafer W.

[0046] The other cutting water supply nozzle 72b does not supply cutting water 40. Also, the shower nozzle 73a (FIG. 2) does not supply cooling water. In this way, by restricting the supply of cutting water from the other nozzles except for the cutting water supply nozzle 72a closer to the center Wc of the wafer W, the flow direction of the cutting water is restricted to be from the inside (center side) to the outside of the wafer.

[0047] In this manner, the cutting debris 50 generated by cutting is removed from the inside to the outside of the wafer W, and the amount of cutting debris 50 (particles) remaining on the surface of the wafer can be reduced. Also, by forming a flow of cutting water from the inside to the outside of the wafer W, the cutting water is less likely to flow toward the inside of the wafer, and the cutting water containing the cutting debris is prevented from moving toward the wafer surface.

[0048] Fig. 7(A) is an image of the distribution of cutting chips 50 remaining on the surface of the wafer W when the processing method according to the present invention is carried out. As a comparative example, Fig. 7(B) is an image of the distribution of cutting chips 50 remaining on the surface of the wafer W when cutting water is supplied from the other cutting water supply nozzle 72b (Fig. 5) in addition to the cutting water supply nozzle 72a (Fig. 5).

[0049] As can be seen from this image, according to the present invention, as shown in Fig. 7(A), it is possible to reduce cutting waste 50 (particles) remaining on the surface of the wafer W during edge trimming. This makes it possible to improve the cleanliness after cleaning, for example, when cleaning is performed in the cleaning device 6 (Fig. 1) after edge trimming. Also, for example, when bonding another wafer after edge trimming, bonding can be performed with a higher degree of cleanliness.

[0050] After the above-mentioned edge trimming process, for example, bonding with another wafer is performed, and further other processes are carried out.

[0051] In addition, after the edge trimming process described above, the back surface of the wafer is ground by another grinding device, for example, to thin the wafer. The thinned wafer is again diced by the above-mentioned cutting device. During this dicing process, in the configuration shown in Figures 4 and 5, cutting water is supplied from the other cutting water supply nozzle 72b in addition to the cutting water supply nozzle 72a. Cooling water is also supplied from the shower nozzle 73a (Figure 2). [Explanation of symbols]

[0052] 2 Cutting equipment 6. Cleaning Equipment 8 Holding Table 10 Controller 20 Cutting unit 21 Cutting blade 23 Spindle 24 Mounting flange 40 Cutting water 50 Cutting waste 72a Cutting water supply nozzle 72b Cutting water supply nozzle 72d cutting water injection port 73 Nozzle Block 73a Shower nozzle 84f Control valve 85f Control valve 85g Control valve 86 Cutting water supply source 87 Cooling water supply source F Annular frame K processing point T-Tape U Wafer Unit W wafer Wa Surface Wc center Wg Outer circumference Wt trimming part Wz Thickness direction

Claims

1. A processing method for cutting and trimming an outer periphery of a surface of a wafer with a cutting blade, comprising: During cutting, from a cutting water supply nozzle closer to the center of the wafer than the cutting blade, Supplying cutting water toward a side farther from the center of the wafer; Processing method.

2. a cutting water supply nozzle located closer to the center of the wafer than the cutting blade; a cutting water supply nozzle located farther from the center of the wafer than the cutting blade; In an apparatus configuration comprising: During cutting, Cutting water is supplied only from the cutting water supply nozzle close to the center of the wafer. The processing method according to claim 1 .

3. A cutting device for carrying out the processing method according to claim 1 or 2, a cutting water supply nozzle located closer to the center of the wafer than the cutting blade; a cutting water supply nozzle located farther from the center of the wafer than the cutting blade; a cutting water supply passage for supplying cutting water to each of the cutting water supply nozzles; a control valve provided in each of the cutting water supply paths for controlling whether or not cutting water is supplied to each of the cutting water supply nozzles; A controller for controlling the operation of each of the control valves; A cutting device having

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