JP2022032453A - Cutting device and processing method - Google Patents

Abstract

To provide a cutting device and a processing method such that electrostatic discharge damage to the device can be avoided, and neither a cylinder for storing CO2 nor a storage space for the cylinder is required.SOLUTION: In a cutting device, processing liquid supply means 20 comprises a water storage tank 21 for reserving pure water L0, a nozzle 24 which communicates with the water storage tank, and supplies processing liquid L1 to a wafer and a cutting blade 43; an anode diamond electrode 26A and a cathode diamond electrode 26B which are inserted into the water storage tank; and a DC power supply 27. The processing liquid is placed in a conductive state by applying the anode diamond electrode and cathode diamond electrode dipped in the pure water in the water storage tank with electricity from the DC power supply 27, and thus desorbing hydrogen H2 and generating an OH radial. The cutting blade arranged rotatably at the cutting means 4 is positioned at a wafer held on a chuck table, and the wafer is cut while the processing liquid is supplied to a cutting position.SELECTED DRAWING: Figure 2

Description

The present invention relates to a cutting apparatus configured to include a machining fluid supply means, and a machining method for cutting a wafer while supplying the machining fluid.

A wafer in which a plurality of devices such as ICs and LSIs are partitioned by a scheduled division line and formed on the surface is divided into individual device chips by a dicing device and used for electric devices such as mobile phones and personal computers.

The dicing device includes a holding means for holding the wafer, a cutting means for rotatably provided with a cutting blade for cutting the wafer held by the holding means, and a machining liquid supply means for supplying the machining liquid to the wafer and the cutting blade. The wafer can be divided into individual device chips with high precision.

When pure water is used as the processing liquid, since pure water has a high specific resistance value, there is a problem that static electricity is generated by friction at the machined portion and charged to a high voltage, causing electrostatic breakdown in the device. On the other hand, by mixing CO ₂ into pure water, the specific resistance value is lowered to increase the conductivity, and electrostatic destruction of the device is avoided (see, for example, Patent Document 1).

Japanese Unexamined Patent Application Publication No. 2003-291665

However, in the technique described in Patent Document 1 described above, there is a problem that productivity is poor because a cylinder for storing CO ₂ to be mixed with pure water is prepared and a storage space for the cylinder is also required.

The present invention has been made in view of the above facts, and its main technical problem is that when cutting is performed while supplying a processing liquid, electrostatic destruction of the device can be avoided and a cylinder for storing CO ₂ can be avoided. , And a cutting device and a processing method that do not require the storage space of the cylinder.

In order to solve the above-mentioned main technical problem, according to the present invention, a holding means for holding a waha, a cutting means for rotatably providing a cutting blade for cutting the waha held by the holding means, and a waha and a cutting blade. It is a cutting device configured to include a machining liquid supply means for supplying a machining fluid, and the machining fluid supply means includes a water storage tank for storing pure water, a wafer and a cutting blade communicating with the water storage tank. The processing liquid is provided with a nozzle for supplying the processing liquid, an anode diamond electrode and a cathode diamond electrode inserted into the water storage tank, and a DC power supply, and the processing liquid is immersed in pure water in the water storage tank. Provided is a cutting apparatus in which electricity is applied to the diamond electrode and the cathode diamond electrode from the DC power source to release hydrogen and generate OH radicals to have conductivity.

The specific resistance value of the pure water is preferably 18 MΩ · cm or more. Further, the cutting apparatus of the present invention is provided with a surfactant tank containing a solution of the surfactant, the surfactant is mixed in the processing liquid, and the OH radical decomposes the organic substance of the surfactant, and the detergent is used. It is preferable to generate CO ₂ in the processing liquid.

Further, according to the present invention, there is a method for processing a wafer that divides the wafer into individual device chips, that is, a pure water storage step of storing pure water in a water storage tank, and an anode diamond electrode and a cathode diamond electrode in the water storage tank. The electrode insertion step of inserting the water, the power application step of applying DC power to the anode diamond electrode and the cathode diamond electrode, and the OH radical generated by removing hydrogen from the pure water in the water storage tank provide conductivity. A machining fluid generation process that generates machining fluid and a cutting blade that is rotatably arranged in the cutting means are positioned on the wafer held by the holding means, and the wafer is cut while supplying the machining fluid to the cutting position. A processing method including a process and a processing method including the process is provided.

The specific resistance value of the pure water used in the processing method of the present invention is preferably 18 MΩ · cm or more. Further, in the cutting step, it is preferable to mix a surfactant in the processing liquid and the OH radical decomposes organic substances in the surfactant to generate and supply CO ₂ to cut the wafer.

The cutting apparatus of the present invention has a holding means for holding a waha, a cutting means for rotatably provided with a cutting blade for cutting the waha held by the holding means, and a process for supplying a processing liquid to the waha and the cutting blade. A cutting device including a liquid supply means, wherein the machining liquid supply means is a water storage tank for storing pure water, and a nozzle that communicates with the water storage tank and supplies the machining liquid to a wafer and a cutting blade. An anode diamond electrode and a cathode diamond electrode to be inserted into the water storage tank, and a DC power supply, and the processing liquid is applied to the anode diamond electrode and the cathode diamond electrode immersed in pure water in the water storage tank. Since electricity is applied from the DC power source to release hydrogen to generate OH radicals to provide conductivity, the device formed on the wafer is prevented from being electrostatically destroyed. In addition, since a CO ₂ cylinder is not required when the pure water is in a conductive state, a space for storing the CO ₂ cylinder and the CO ₂ cylinder becomes unnecessary, which causes a problem of poor productivity. do not do. In addition, since the electrode that generates the anodic reaction when electrolyzing pure water to generate OH radicals is a diamond electrode, the quality of the device can be improved without metal ions derived from the electrodes being mixed in the processing liquid. It does not decrease.

Further, the processing method of the present invention includes a pure water storage step of storing pure water in a water storage tank, an electrode insertion step of inserting an anode diamond electrode and a cathode diamond electrode into the water storage tank, and the anode diamond electrode and the cathode diamond. A power application process in which DC power is applied to the electrodes, a processing liquid generation process in which hydrogen is separated from the pure water in the water storage tank and OH radicals are generated to generate a processing liquid having conductivity, and a rotation to the cutting means. It is carried out in the cutting process because it includes a cutting process in which the possibly arranged cutting blades are positioned in the waha held by the holding means and the waha is cut while supplying the machining fluid to the cutting position. In the cutting process, the device formed on the wafer is prevented from being electrostatically destroyed. Further, when the specific resistance value of pure water is lowered to have conductivity, the CO ₂ cylinder and the place for storing the CO ₂ cylinder become unnecessary, and the problem of poor productivity does not occur. In addition, since the electrode that generates the anodic reaction when electrolyzing pure water to generate OH radicals is a diamond electrode, the quality of the device can be improved without metal ions derived from the electrodes being mixed in the processing liquid. It does not decrease.

It is an overall perspective view of the cutting apparatus of this embodiment. It is a conceptual diagram which shows more concretely the processing liquid supply means shown in FIG. It is a partially enlarged perspective view which shows the embodiment of a cutting process.

Hereinafter, embodiments relating to a cutting device for cutting a wafer configured based on the present invention and a processing method for cutting a wafer will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an overall perspective view of the cutting apparatus 1 of the present embodiment. The cutting device 1 in the illustrated embodiment includes a substantially rectangular device housing 2, and is provided on a chuck table 3 and a chuck table 3 arranged as holding means for holding the wafer W which is the workpiece of the present embodiment. It includes a cutting means 4 rotatably provided with a cutting blade 43 for cutting the held wafer W, and a machining liquid supply means 20 for supplying the machining liquid to the cutting position. As shown in the figure, the wafer W processed in the present embodiment is, for example, a semiconductor wafer having a substantially disk shape, in which a plurality of devices are partitioned by a planned division line and formed on the surface. , Supported by the annular frame F via the adhesive tape T.

Further, the cutting device 1 carries out a cassette 5 accommodating a plurality of wafers W, a temporary storage table 6 for carrying out and temporarily placing the wafer W housed in the cassette 5, and carrying out the wafer W to the temporary storage table 6. The input means 7, the transport means 8 for swirling and transporting the wafer W carried out to the temporary placement table 6 onto the chuck table 3, and the cleaning means 9 for cleaning the wafer W machined by the cutting means 4 (details are as follows. (Omitted), the cleaning and transporting means 10 that transports the machined wafer W from the chuck table 3 to the cleaning means 9, the imaging means 11 that images the wafer W on the chuck table 3, and the control (not shown). It has the means. The cassette 5 is placed on a cassette table 5a arranged so as to be movable up and down by an elevating means (not shown), and when the wafer W is carried out from the cassette 5 by the loading / unloading means 7, the height of the cassette 5 is high. Is adjusted accordingly.

In the device housing 2, the chuck table 3 and the cutting means 4 are relatively machined and fed, and more specifically, the chuck table 3 is moved in the X-axis direction indicated by the arrow X, which is the cutting feed direction. An X-axis feeding means (not shown) for moving is provided. The chuck table 3 includes a suction chuck 31 that constitutes the upper surface of the chuck table 3 and has air permeability, and sucks the wafer W together with the frame F on the mounting surface that is the surface of the suction chuck 31 via the adhesive tape T. It is designed to be sucked and held by means (not shown). Further, the chuck table 3 is configured to be rotatable by a rotation mechanism (not shown).

The cutting means 4 is mounted on a moving base (not shown) and is moved and adjusted in the Y-axis direction indicated by the arrow Y, which is the indexing direction, and in the Z-axis direction indicated by the arrow Z, which is the cutting direction, and the housing 41. A spindle 42 rotatably supported and driven by a motor (not shown), and a wafer W mounted on the tip end side of the spindle 42 protruding from the housing 41 and rotatably supported and held by the chuck table 3. A cutting blade 43 for cutting the cutting blade 43 and a blade cover 44 surrounding the cutting blade 43 are provided.

FIG. 2 shows more specifically the machining fluid supply means 20 arranged in the cutting apparatus 1 shown in FIG. The processing liquid supply means 20 is a water storage tank 21 for storing pure water L0, and a nozzle for supplying the processing liquid L1 generated from the pure water L0 in the water storage tank 21 to the wafer W and the cutting blade 43 via the communication passage 22a. 24, 24, an anode diamond electrode 26A and a cathode diamond electrode 26B inserted into the water storage tank 21, and a DC power supply 27 for applying DC electricity to the anode diamond electrode 26A and the cathode diamond electrode 26B. As the anode diamond electrode 26A and the cathode diamond electrode 26B, for example, an electrode in which the surface of a metal plate is coated with a thin film of conductive diamond can be adopted. Further, the voltage applied from the DC power supply 27 when the switch 27a is turned _on causes an electrolytic reaction in the anode diamond electrode 26A immersed in the pure water L0, for example, and separates the hydrogen H2 from the pure water L0. It is about 2.8V to generate OH radical (hydroxyl radical, which is indicated as "OH." In the figure). An on-off valve 25 and a pressure feed pump 23 are arranged on the communication passage 22a.

_The water storage tank 21 is provided with hydrogen recovery means 28 for recovering hydrogen H2 generated by applying direct current electricity to pure water L0. The hydrogen recovery means 28 includes a recovery cylinder 28a that covers the upper part of the water storage tank 21, and a discharge path _28b that discharges the hydrogen H2 recovered by the recovery cylinder 28a. The hydrogen H ₂ discharged from the discharge passage 28b can be treated, for example, by storing it in a hydrogen storage alloy or combining it with oxygen by utilizing a catalytic oxidation reaction to generate water.

Further, in the present embodiment, the surfactant tank 30 for storing the surfactant Ld is connected to the processing liquid supply means 20. The surfactant tank 30 is connected to the pressure feed pump 23 via the communication passage 32, and an on-off valve 33 is arranged on the communication passage 32. The pressure feed pump 23, the on-off valve 25, the switch 27a, and the on-off valve 33 are connected to the control means, and the instruction signal output by the control program stored in the control means or the instruction of the operator is followed. It is controlled by an instruction signal output via the control means.

The cutting apparatus 1 of the present embodiment has substantially the same configuration as described above, and the working effects of the cutting apparatus 1 and the machining method for cutting the wafer W while supplying the machining fluid L1 will be described in more detail below. do.

In the present embodiment, the wafer processing method for performing the cutting process for dividing the wafer W held by the chuck table 3 into individual device chips includes the following steps. When the cutting process of the present embodiment is performed, the wafer W housed in the cassette 5 shown in FIG. 1 is pulled out to the temporary storage table 6 by the loading / unloading means 7, and is pulled out from the temporary storage table 6 by the transporting means 8. It is conveyed to the chuck table 3, and as shown in FIG. 3, the surface Wa of the wafer W is placed and held with its surface facing upward. As shown in the figure, in the wafer W of the present embodiment, a plurality of devices D are partitioned by a planned division line Wb and formed on the surface Wa.

When the processing method of the present embodiment is carried out, pure water L0 is stored in the water storage tank 21 of the above-mentioned processing liquid supply means 20 (see FIG. 2) (pure water storage step). The pure water L0 stored here may be so-called ultrapure water having a specific resistance value of 18 MΩ · cm or more in order to electrolyze and generate OH radicals satisfactorily in the processing liquid generation step described later. preferable.

When pure water L0 is stored in the water storage tank 21 as described above, the anode diamond electrode 26A and the cathode diamond electrode 26B are inserted into the water storage tank 21, and the anode diamond electrode 26A and the anode diamond electrode 26A and the cathode diamond electrode 26B are inserted into the pure water L0 in the water storage tank 21. The cathode diamond electrode 26B is immersed (electrode insertion step). The order in which the pure water storage step and the electrode insertion step described above are carried out is not particularly limited, and the electrode insertion step may be carried out first.

The wafer W is positioned directly under the image pickup means 11 (see FIG. 1) of the cutting device 1 by operating the feed means (not shown) for moving the chuck table 3, and the image pickup means. Imaged by 11, the predetermined division scheduled line Wb of the wafer W is aligned in the X-axis direction, and the alignment with the cutting blade 43 is performed.

Next, the switch 27a of the DC power supply 27 is operated to apply DC power to the anode diamond electrode 26A and the cathode diamond electrode 26B (power application step). As described above, the voltage applied by the DC power supply 27 is about _2.8 V, and as a result of carrying out the power application step, hydrogen H2 is separated from the pure water L0 by the anodic reaction at the anodic diamond electrode 26A. An OH radical is generated, the specific resistance value is lowered, and a working liquid L1 having conductivity is generated (working liquid generation step). The hydrogen H ₂ generated in this processing liquid generation step is recovered by the hydrogen recovery means 28 described above.

When the machining fluid L1 is generated from the pure water L0 in the water storage tank, the pressure feed pump 23 is operated and the open / close valve 25 is opened, and as shown in FIG. 3, the nozzle 24 is positioned in the vicinity of the cutting blade 43. The processing liquid L1 is sprayed from. At the same time, the cutting means 4 is operated to position the cutting blade 43 rotated at high speed in the direction indicated by the arrow R1 at the scheduled division line Wb aligned in the X-axis direction and cut from the surface Wa side of the waha W. The chuck table 3 is machined and fed in the X-axis direction to form the dividing groove 100 (cutting step). The machining fluid L1 jetted from the nozzle 24 is sprayed to the cutting position and supplied to the cutting blade 43 and the wafer W to cool the cutting blade 43 and remove cutting chips from the cutting position for cleaning. do.

As described above, if the division groove 100 is formed on the predetermined division schedule line Wb, the division groove 100 is adjacent to the division schedule line Wb on which the division groove 100 is formed in the Y-axis direction, and the division groove 100 is not yet formed. The cutting blade 43 of the cutting means 4 is indexed and fed onto the scheduled division line Wb, and the cutting process for forming the division groove 100 is performed in the same manner as described above. By repeating these steps, the dividing groove 100 is formed along all the scheduled division lines Wb along the X-axis direction. Next, the chuck table 3 is rotated 90 degrees to align the direction orthogonal to the direction in which the dividing groove 100 was formed earlier in the X-axis direction, and all the division plans in which the above-mentioned cutting process is newly aligned in the X-axis direction. This is performed on the line Wb, and the dividing groove 100 is formed along all the planned division lines Wb formed on the wafer W. By carrying out the division step in this way, the wafer W is divided into device chips for each device D. The wafer W divided in this way is transported to the cleaning means 9 by the cleaning transport means 10, washed and dried, transported by the transport means 8 and the loading / unloading means 7, and housed in a predetermined position of the cassette 5. Wash.

Since the above-mentioned processing liquid L1 is in a state of having conductivity by generating OH radicals by the above-mentioned processing liquid supply means 29, the wafer W is charged even if static electricity is generated due to friction during cutting. The device D is prevented from being electrostatically destroyed. Further, since the CO ₂ cylinder is not required when the pure water L0 is in a conductive state, the space for storing the CO ₂ cylinder and the CO ₂ cylinder becomes unnecessary, and there is a problem that the productivity is poor. Does not occur. Further, since the diamond electrode is used as an electrode for generating an anodic reaction when the pure water L0 is electrolyzed to generate OH radicals, the quality of the device D can be improved without metal ions being mixed in the processing liquid L1. It does not decrease.

As described above, the surfactant tank 30 storing the surfactant Ld is connected to the machining liquid supply means 20 of the present embodiment, and the surfactant tank 30 is connected to the machining liquid supply means 20 of the present embodiment at the cutting position by the cutting blade 43 via the nozzles 24 and 24. When the processing liquid L1 is supplied from the water storage tank 21, the surfactant Ld can be mixed with the processing liquid L1 at a predetermined ratio. By doing so, a part of the organic substance contained in the surfactant Ld is decomposed by the OH radical in the processing liquid L1 to generate CO ₂ . That is, CO ₂ can be added to the processing liquid L1 without disposing the CO ₂ cylinder, and by containing the surfactant Ld in the processing liquid L1, the processing liquid L1 functions as a cutting oil and is processed. The conductivity of the liquid L1 is ensured, and electrostatic destruction of the device D on the wafer W is avoided as in the case where the processing liquid L1 is supplied alone.

Further, as described above, the inclusion of OH radicals in the processing liquid L1 has the effect of purifying the pollutants contained in the waste liquid after cutting, and the waste liquid is also purified at the same time, so that it is environmentally friendly. Treated as a gentle waste liquid.

1: Cutting device 2: Device housing 3: Chuck table 31: Suction chuck 4: Cutting means 41: Housing 42: Spindle 43: Cutting blade 44: Blade cover 5: Cassette 6: Temporary placement table 7: Carrying in / out means 8: Transport Means 9: Cleaning means 10: Cleaning transport means 11: Imaging means 20: Machining liquid supply means 21: Water storage tank 22a: Communication passage 23: Pressure pump 24: Nozzle 24a: Machining liquid introduction port 25: Open / close valve 26A: Anodized diamond electrode 26B: Cathode diamond electrode 27: DC power supply 27a: Switch 28: Hydrogen recovery means 30: Surface active agent tank 32: Communication passage 33: Open / close valve

Claims (6)

Includes a holding means for holding the wafer, a cutting means rotatably provided with a cutting blade for cutting the wafer held by the holding means, and a machining liquid supply means for supplying the machining liquid to the wafer and the cutting blade. It is a configured cutting device
The processing liquid supply means includes a water storage tank that stores pure water, a nozzle that communicates with the water storage tank and supplies the processing liquid to the wafer and the cutting blade, and an anode diamond electrode and a cathode diamond electrode that are inserted into the water storage tank. And with a DC power supply,
The processing liquid has conductivity by applying electricity from the DC power source to the anode diamond electrode and the cathode diamond electrode immersed in pure water in the water storage tank to release hydrogen and generate OH radicals. Cutting equipment that is said to be. The cutting apparatus according to claim 1, wherein the specific resistance value of the pure water is 18 MΩ · cm or more. A surfactant tank containing a solution of a surfactant is provided, the surfactant is mixed into the processing liquid, and OH radicals decompose organic substances of the surfactant to generate CO ₂ in the processing liquid. The cutting apparatus according to claim 1 or 2. It is a processing method of a wafer that divides the wafer into individual device chips.
A pure water storage process that stores pure water in a water storage tank,
An electrode insertion step of inserting an anode diamond electrode and a cathode diamond electrode into the water storage tank, and
A power application step of applying DC power to the anode diamond electrode and the cathode diamond electrode, and
A processing liquid generation step of producing a processing liquid having conductivity by OH radicals generated by removing hydrogen from pure water in the water storage tank, and
A cutting process in which a cutting blade rotatably arranged on the cutting means is positioned on the wafer held by the holding means, and the wafer is cut while supplying the processing liquid to the cutting position.
A processing method that includes. The processing method according to claim 4, wherein the specific resistance value of the pure water is 18 MΩ · cm or more. The processing method according to claim 4 or 5, wherein in the cutting step, a surfactant is mixed with the processing liquid, and the OH radical decomposes organic substances in the surfactant to generate CO ₂ to cut the wafer. ..

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