Chiller unit

Abstract

To provide a chiller unit which enables an operator of a device in which the chiller unit is disposed to discover leakage of a liquid circulating in the chiller unit early by using ultraviolet light radiating means.SOLUTION: A chiller unit 30 includes: a circulation path 31 for circulating a liquid; and temperature adjusting means 34 which is disposed at the circulation path to adjust the liquid to a predetermined temperature. An ultraviolet absorber is mixed into the liquid. An operator can radiate ultraviolet light to a processing area and sense leakage of the cooling liquid from a spindle housing 81 of a spindle unit 80 and the circulation path 31 of the chiller unit 30.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a chiller unit that circulates liquid regulated to a predetermined temperature. [Background technology]

[0002] A wafer having a plurality of devices such as ICs and LSIs formed on its front surface and partitioned along intended dividing lines is ground on its back surface by a grinding device to a specified thickness, and then the intended dividing lines are cut by a cutting device to separate the wafer into individual device chips for use in electrical equipment such as mobile phones and personal computers.

[0003] In addition, the grinding means that constitutes the grinding device is equipped with a spindle unit that is generally composed of a spindle on which a grinding wheel with a grinding stone is rotatably mounted, and a spindle housing that supports the spindle with an air bearing, and to prevent the spindle from expanding or contracting due to heat, a chiller unit (cooling mechanism) is provided that keeps the spindle unit at a constant temperature by running a liquid (constant temperature water) maintained at a predetermined temperature as a circulating liquid through piping arranged within the spindle housing.

[0004] As described above, the cutting means constituting the cutting device has a spindle unit roughly composed of a spindle to which a cutting blade is attached and a spindle housing that supports the spindle with an air bearing, and as in the grinding device described above, a chiller unit is provided to keep the spindle unit at a constant temperature (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2007-38329 A [Patent Document 2] JP 2009-202295 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned chiller unit, the liquid circulating in the chiller unit may leak due to aging or vibration of the device mounted thereon. If the operator does not notice the liquid leakage and continues to operate the device, the spindle may not be sufficiently cooled, the machining accuracy may not be maintained, and the quality of the workpiece may deteriorate. Furthermore, if the operation is continued without noticing the liquid leakage, the spindle unit may eventually be damaged due to thermal expansion of the spindle. Such various problems caused by the failure of the cooling function are not limited to the above-mentioned grinding device or cutting device, but may occur in all chiller units that cool devices that need to be kept at a constant temperature.

[0007] The present invention has been made in consideration of the above-mentioned facts, and its main technical object is to provide a chiller unit that enables an operator of an apparatus in which a chiller unit is installed to detect leakage of liquid circulating through the chiller unit at an early stage, and can solve problems such as insufficient cooling of the object to be cooled by the chiller unit, such as a spindle, resulting in reduced machining accuracy and reduced quality of the device chips that are individually separated, or damage to the spindle unit due to thermal expansion of the spindle. [Means for solving the problem]

[0008] In order to solve the above-mentioned main technical problem, according to the present invention, there is provided a chiller unit that circulates a liquid regulated to a predetermined temperature, the chiller unit including a circulation path for circulating the liquid, and temperature regulation means disposed in the circulation path for regulating the liquid to the predetermined temperature, wherein an ultraviolet absorbing agent is mixed into the liquid.

[0009] The liquid is preferably water, and the water preferably contains an antifreeze liquid. Effect of the Invention

[0010] The chiller unit of the present invention includes a circulation path for circulating a liquid, and a temperature adjustment means disposed in the circulation path for adjusting the liquid to a predetermined temperature. Since the liquid has an ultraviolet absorbing agent mixed in, an operator of the equipment in which the chiller unit is disposed can use the ultraviolet irradiation means to detect leaks in the liquid circulating through the chiller unit at an early stage, thereby eliminating problems such as insufficient cooling of the object to be cooled by the chiller unit, such as a spindle, resulting in reduced machining accuracy and reduced quality of the device chips that are individually divided, or damage to the spindle unit due to thermal expansion of the spindle. [Brief description of the drawings]

[0011] [Figure 1] 1 is an overall perspective view of a cutting device to which the chiller unit of this embodiment is attached. FIG. [Diagram 2] 2 is a circuit diagram of a chiller unit attached to the cutting device shown in FIG. 1 and an exploded perspective view of a spindle unit. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a chiller unit configured based on the present invention will be described in detail with reference to the accompanying drawings.

[0013] FIG. 1 shows a cutting device 1 equipped with cutting means 8 including a spindle cooled by a chiller unit 30 described below. The cutting device 1 has a housing 2 having an approximately rectangular parallelepiped shape, and is equipped with a cassette 4 (shown by a two-dot chain line) placed on a cassette table 4a of the housing 2, a loading / unloading means 3 for transporting the wafer W supported on a frame F via a protective tape T from the cassette 4 to a temporary placement table 5, a transporting means 6 having a rotating arm for transporting the wafer W transported to the temporary placement table 5 to the chuck table 7a of the holding means 7, a cutting means 8 for performing cutting processing on the wafer W held by suction on the chuck table 7a, an alignment means 10 for imaging the wafer W held on the chuck table 7a and detecting the area to be cut by the cutting means 8, a cleaning and unloading means 14 for transporting the wafer W from the loading / unloading position where the chuck table 7a is positioned in Figure 1 to a cleaning device 12 (details are omitted), and a control means, a display means, etc. not shown.

[0014] In addition, on the upper surface of the housing 2 of the cutting device 1 shown in Figure 1, the processing area in which the loading / unloading means 3, cassette 4, temporary placement table 5, transporting means 6, holding means 7, cutting means 8, etc. are arranged is covered by a cover member and a door not shown, and maintenance such as replacing the cutting blade of the cutting means 8 or replacing the chuck table 7a of the holding means 7 is performed by an operator by opening and closing the door arranged near the cutting means 8.

[0015] 2 shows a circuit diagram of a spindle unit 80 (only a part of which is shown) constituting the above-mentioned cutting means 8, and a chiller unit 30 which is connected to the spindle unit 80 and cools the cutting means 8 by circulating a cooling liquid L adjusted to a predetermined temperature. The chiller unit 30 is accommodated in the housing 2 of the above-mentioned cutting device 1.

[0016] 2 shows an exploded perspective view of a spindle housing 81 of a spindle unit 80. The illustrated spindle housing 81 includes a cylindrical housing main body 81a in which the liquid L circulates inside the wall surface, and a tip portion 82 that constitutes the tip of the spindle housing 81. For convenience of explanation, the spindle, which is rotatably accommodated in an internal space 81b of the spindle housing 81 via an air bearing and has a cutting blade attached to its tip, a blade cover that covers the cutting blade, a drive motor that drives the spindle, and the like are omitted.

[0017] A base 83 is connected to the housing main body 81a, which supplies and discharges cooling liquid L to the spindle housing 81. The liquid L introduced from a circulating liquid inlet 83a of the base 83 passes through a liquid passage (not shown) within the base 83, a liquid passage 81c within the housing main body 81a, and a liquid passage 82a within the tip portion 82, thereby cooling the entire spindle unit 80, and is discharged from a liquid outlet 83b of the base 83 and returned to the chiller unit 30.

[0018] The chiller unit 30 includes a circulation path 31 that circulates the liquid L within the spindle housing 81, and a temperature adjustment means 34 that is disposed in the circulation path 31 and adjusts the liquid L to a predetermined temperature.

[0019] The temperature adjustment means 34 includes a refrigerant circulation path 341 in which the refrigerant Q circulates to cool the liquid L in the circulation path 31, a compressor 342 disposed in the refrigerant circulation path 341 and driven by a motor 342a to compress the refrigerant Q, a condenser 343 that liquefies the refrigerant Q by cooling the refrigerant Q carrying the heat of compression generated when the compressor 342 compresses the refrigerant Q, an evaporator 344 that vaporizes the refrigerant Q liquefied in the condenser 343 to generate heat of vaporization, and a variable expansion valve 345 that adjusts the flow rate of the refrigerant Q liquefied by passing through the condenser 343 and introduced into the evaporator 344. A drive mechanism (not shown) is disposed in the variable expansion valve 345, and the opening degree is controlled by the control means described above.

[0020] A pump 311 for circulating the liquid L and a temperature sensor 312 for detecting the temperature of the liquid L after passing through the evaporator 344 in the circulation path 31 are disposed in the circulation path 31 through which the liquid L circulates. The pump 311 is driven by a motor 311a. The temperature detected by the temperature sensor 312 is sent to and stored in a control means (not shown).

[0021] The condenser 343 is connected to an industrial water passage 36 through which industrial water S flows for cooling the refrigerant Q passing through the condenser 343, and a heat exchanger (not shown) arranged in the condenser 343 exchanges heat between the refrigerant Q flowing through the refrigerant circulation passage 341 and the industrial water S passing through the passage, thereby cooling and liquefying the refrigerant Q.

[0022] Inside the evaporator 344, a heat exchanger (not shown) is provided for exchanging heat between the refrigerant Q passing through the refrigerant circulation path 341 and the liquid L passing through the circulation path 31, and the liquid L introduced into the spindle unit 80 and heated is cooled in the evaporator 344. As described above, the temperature sensor 312 is provided in the circulation path 31, and based on the temperature detected by the temperature sensor 312, the flow rate and temperature of the refrigerant Q are adjusted by adjusting the opening degree of the variable expansion valve 345 of the temperature adjustment means 34 described above and the compression amount of the refrigerant Q by the compressor 342, and the temperature of the liquid L introduced into the spindle unit 80 by the circulation path 31 is adjusted to a predetermined temperature (e.g., 20°C).

[0023] The cooling liquid L in this embodiment is obtained by mixing an ultraviolet ray absorbent P into water L0, which is the main component of the liquid L. As the ultraviolet ray absorbent P in this embodiment, a fluorescent agent having a fluorescent performance of absorbing the energy of ultraviolet rays and emitting light when irradiated with the ultraviolet ray can be used, and can be selected from well-known fluorescent agents such as bis(triazinylamino)stilbene disulfonic acid derivatives and bisstyrylbiphenyl derivatives.

[0024] In addition, antifreeze liquid R is mixed into the water L0 and ultraviolet light absorbent P that constitute the liquid L in this embodiment. By mixing the antifreeze liquid R into the liquid L, the liquid L is prevented from freezing due to supercooling when being cooled by the temperature adjustment means 34, and the rust inhibitor and antioxidant contained in the antifreeze liquid R can provide the effect of preventing rust and corrosion of the circulation path 31 including the heat exchanger in the evaporator 344.

[0025] The chiller unit 30 described above and the cutting device 1 to which the chiller unit 30 is attached are generally configured as described above, and the effects of the chiller unit 30 of this embodiment will be described below.

[0026] When cutting is performed in the cutting device 1, first, the wafer W stored in the cassette 4 is gripped by the carry-in / out means 3 and carried out to the temporary placement table 5. The wafer W is a wafer on whose surface a plurality of devices are partitioned by a division line, and is held by an annular frame F via a protective tape T, as shown in FIG. 1. After the wafer W is carried out to the temporary placement table 5, the frame F holding the wafer W is sucked by the conveying means 6 and conveyed to the chuck table 7a of the holding means 7, where the wafer W is placed with its front surface facing upward, and the suction means (not shown) is operated to hold the wafer W by suction. Next, the chuck table 7a is moved, and the wafer W held on the chuck table 7a is imaged by the alignment means 10, and the predetermined division line of the wafer W is aligned in the X-axis direction, and the position is aligned with the cutting blade of the cutting means 8. Next, a cutting blade rotated at high speed is positioned on the intended division line aligned in the X-axis direction and cuts into the surface side, while the chuck table 7a is moved in the X-axis direction to form a division groove.

[0027] Next, the cutting blade of the cutting means 8 is indexed and fed onto a division line adjacent in the Y-axis direction to the division line on which the division groove is formed and on which no division groove is formed, and a division groove is formed in the same manner as above. By repeating these steps, division grooves are formed along all the division lines along the X-axis direction. Next, the chuck table 7a is rotated 90 degrees, and the direction perpendicular to the direction in which the division groove was previously formed is aligned with the X-axis direction, and the above-mentioned cutting process is performed on all the division lines newly aligned in the X-axis direction, and division grooves are formed along all the division lines formed on the wafer W. By performing the cutting process in this manner, the wafer W is divided into individual device chips. Next, the wafer W is transported to the cleaning device 12 by the cleaning and transporting means 14, where it is cleaned and dried, and the wafer W after cleaning and drying is stored in a predetermined position in the cassette 4 by the transporting means 6 and the carrying-in / out means 3. Such cutting process is performed on all the wafers W stored in the cassette 4.

[0028] During the above-mentioned cutting process, liquid L adjusted to a predetermined temperature (e.g., 20°C) by the chiller unit 30 is supplied to the circulation path 31 of the chiller unit 30 to cool the spindle rotatably held by the spindle unit 80. This suppresses thermal expansion of the spindle, and maintains the machining accuracy in the cutting process.

[0029] Here, when maintenance such as changing the workpiece, replacing the cutting blade due to wear of the cutting blade, or cleaning the inside of the cutting device 1 becomes necessary, an operator opens a door (not shown) for accessing the processing area of ​​the cutting device 1. The operator can use an ultraviolet irradiation means (black light) to irradiate ultraviolet rays toward the inside of the door, that is, the processing area including the vicinity of the cutting means 8. If the cooling liquid L leaks from the spindle housing 81 of the spindle unit 80 or the circulation path 31 of the chiller unit 30, the ultraviolet absorbing agent P contained in the liquid L exposed to the ultraviolet rays reacts to the ultraviolet rays and emits light. This allows the operator to immediately detect the leakage of the liquid L flowing through the circulation path 31, and to investigate the cause of the leakage and repair the leaking part or replenish the liquid L. As a result, the problem of the quality of the device chip deteriorating due to insufficient cooling of the spindle and the processing accuracy not being maintained can be solved, and further, the problem of the spindle unit 80 being damaged due to thermal expansion of the spindle can also be solved.

[0030] In the above embodiment, the operator uses the ultraviolet irradiation means to irradiate the processing area with ultraviolet rays, but the present invention is not limited to this. For example, an ultraviolet irradiation means for irradiating ultraviolet rays may be arranged in advance inside the cutting device 1 where the processing area is formed, and when the operator opens the door to access the inside of the cutting device 1, the ultraviolet irradiation means may operate for a certain period of time to irradiate the processing area with ultraviolet rays. With this configuration, the operator can immediately detect the leakage of the liquid L.

[0031] In the above embodiment, an example is shown in which the chiller unit 30 configured according to the present invention is applied to a cutting device 1, but the present invention is not limited to this and can also be applied to chillers that cool spindle units arranged in grinding devices and polishing devices, and is not limited to chillers that cool spindle units but can be applied to all chillers that use liquid to cool equipment that needs to be kept at a constant temperature. [Explanation of symbols]

[0032] 1:Cutting device 2: Housing 3: Carrying in / out means 4: Cassette 5: Temporary table 6: Means of transportation 7: Holding means 7a: Chuck table 8: Cutting means 80: Spindle unit 81: Spindle housing 81a: Housing body 81b:Inner space 81c:Liquid path 82:Tip 82a:Liquid path 83: Base 83a: Liquid inlet 83b:Liquid outlet 10: Alignment means 12: Cleaning equipment 14: Cleaning and transport means 30: Chiller unit 31:Circulation route 311: Pump 312: Temperature sensor 34: Temperature adjustment means 341: Refrigerant circulation path 342: Compressor 343: Condenser 344: Evaporator 345: Variable expansion valve F: Frame L:Liquid L0:Water P: UV absorber Q: Refrigerant R: Antifreeze T: Protective tape W: Wafer

Claims

1. A chiller unit that circulates a liquid adjusted to a predetermined temperature, a circulation path for circulating a liquid; and a temperature adjustment means disposed in the circulation path for adjusting the liquid to a predetermined temperature, A chiller unit in which the liquid contains an ultraviolet absorbing agent.

2. 2. The chiller unit of claim 1, wherein said liquid is water.

3. 3. The chiller unit of claim 2, wherein said water contains an antifreeze liquid.

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