JP2004330362A - Mirror finishing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mirror finishing apparatus which maximizes the working efficiency and manufacturing quality of mirror finishing, and further minimizes the consumption of polishing slurry or make the polishing slurry unnecessary, even in a CMP apparatus using the polishing slurry, by keeping a mechanochemical mirror finish grinding stone in the state where the grinding stone has been slightly wetted from the completely dry state. <P>SOLUTION: The mirror finishing apparatus comprises a wetness control means for controlling the wetness of at least either of the polishing surface of the grinding stone and the surface of a workpiece to be polished. The wetness control means comprises a sliding load monitoring means for monitoring the sliding load of the polishing means, a critical state detecting means for detecting the state where the sliding load to be monitored by the sliding load monitoring means fluctuates unstably; and a control means for setting and keeping the wetness, which is in the optimum state neighboring the critical state detected by the critical state detecting means and slightly exceeds the wetness in the critical state. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mirror finishing apparatus having a grinding means with a chemical action capable of easily maintaining an optimum state by setting and maintaining an optimum humidity for maximizing operation efficiency and manufacturing quality.
[0002]
[Prior art]
Conventionally, in mirror finishing, there has been a method in which stress, micro cracks, and the like generated on a ground surface of a work can be removed by etching means (for example, Patent Document 1). As this type of grinding apparatus with an etching function, there has conventionally been a polishing or etching processing method.
[0003]
As an alternative to a grinding apparatus with an etching function, a grindstone having a chemical action using soft abrasive grains such as silica as fixed abrasive grains has been developed, and a mirror finish processing using the grindstone has been attempted. The grindstone with the chemical action referred to here is based on the mechanochemical phenomenon that occurs at the point of contact between the soft abrasive grains and the workpiece (that is, the chemical reaction of a very small unit induced by the applied mechanical energy). , Mirror finish.
[0004]
In addition, there is a type in which the degree of clogging of the grindstone is estimated by monitoring the power consumption of a drive motor that rotates the rotary grindstone, and the injection pressure of a cleaning liquid for cleaning the rotary grindstone can be optimally controlled (for example, Patent Document 2). This utilizes the effect that when clogging of the grindstone becomes severe, the friction between the workpiece and the grindstone surface is reduced, the sliding load is reduced, and the power consumption of the drive motor is reduced. That is, even during the operation of the mirror finishing device, the degree of deviation from the control target is estimated by monitoring the power consumption of the drive motor with respect to the condition of the grindstone including the grindstone, and the injection pressure of the cleaning liquid is optimized. By feeding back to the control function unit so that it can be controlled, the rotating grindstone is maintained in an optimum state.
[0005]
[Patent Document 1]
JP-A-9-223680 (paragraph number [0002])
[Patent Document 2]
JP-A-2002-178258 (paragraph number [0036], FIG. 6)
[0006]
[Problems to be solved by the invention]
In a conventional dry-type mirror finishing (dry polishing) apparatus provided with a grinding means with a chemical action, the ground surface becomes brittle at a critical region humidity between the dry state and the wet state, and a scratch is formed on the ground surface. There is a critical state which causes the generation and is not suitable for practical use. Therefore, it is necessary to maintain a dry state in order to avoid this critical state.
[0007]
Further, when the surface to be ground is mirror-finished, polishing or etching has been performed after the grinding process. However, polishing and etching take a long time, and consumables such as a polishing slurry, a polishing pad, and an etchant are expensive. Therefore, there is a problem that the cost is increased and a burden on an environment is large when a waste liquid or the like is treated.
[0008]
Therefore, it has been found that, if at least one of the surfaces to be ground of the work is set and maintained at a humidity slightly exceeding the critical state, it is an optimal state for maximizing the operation efficiency and production quality of the mirror finishing device. It is getting. Moreover, it is safe because a critical state can be avoided.
[0009]
As described above, the problem is to establish a technique for stably setting and maintaining an optimum state, and to further develop the technique, for example, it has been used as a lubricant such as a urethane pad containing silica in a CMP (Chemical Mechanical Polishing) apparatus. Another object is to minimize or eliminate the use of expensive polishing slurries.
[0010]
The present invention is directed to a mirror finishing device using dry mirror finishing, in which the mirror finishing device is controlled to an optimum state by stably setting and maintaining the humidity slightly dried from the critical region humidity, thereby improving the operation efficiency. Further, it is an object of the present invention to provide an apparatus capable of maximizing production quality and minimizing or eliminating the use amount of a polishing slurry.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a mirror finishing device including a grinding unit with a chemical action, wherein at least one of a grinding surface of the grinding unit and a surface to be ground of the work is provided. This is a mirror finishing device including a humidity management means for managing humidity.
[0012]
According to the invention according to claim 1, in the grinding means involving a chemical action, the grinding surface becomes brittle at a critical region humidity intermediate between the dry state and the wet state, causing scratches on the ground surface. Since there is a critical state which is considered to be unsuitable for practical use, the humidity control means sets at least one of the grinding surface of the grinding means and the surface to be ground of the work at the optimum humidity and maintains the critical humidity. Avoid the situation.
[0013]
Further, since the humidity slightly exceeding the critical region humidity is in an optimum state for maximizing the operation efficiency and the production quality of the mirror finishing device, if the humidity management means sets and maintains the optimum humidity, You can achieve your goals.
[0014]
According to a second aspect of the present invention, as the humidity management means, a sliding load monitoring means for monitoring a sliding load of the grinding means, and a state in which the sliding load monitored by the sliding load monitoring means fluctuates irregularly. And a control means for setting and maintaining the humidity in an optimal state adjacent to the critical state detected by the criticality detecting means and slightly above the critical state. The mirror finishing device according to claim 1.
[0015]
According to the invention according to claim 2, the causal relationship between the sliding load monitoring result of the sliding load monitoring means and the optimum state is grasped in advance by an experiment, and the control means slightly exceeds the critical region humidity. The optimal state can be stably and easily maintained by setting and maintaining the humidity.
[0016]
According to a third aspect of the present invention, as the sliding load monitoring means, a driving motor power meter that measures power consumption of a driving motor that drives a rotating grindstone, and a stability that determines whether the power consumption is stable or unstable. Determining means, as the control means, control target setting means for setting the critical state when the determination result of the stability determining means becomes unstable, and setting an optimum state adjacent to the critical state as a setting target; A mirror finishing device according to claim 1 or claim 2.
[0017]
The operation and effect of the invention according to claim 3 are as follows.
During the mirror finishing, the driving load of the rotating grindstone, which is the grinding means with the chemical action, is originally smooth, but the grinding surface of the rotating grindstone or the surface to be ground is between the dry state and the wet state. At a certain critical region humidity, the grinding surface becomes brittle and easily collapses, generating a scratch on the surface to be ground, and in the critical state which is unsuitable for practical use, the driving load for driving the rotary grindstone fluctuates unstablely, The measured value of the drive motor power consumption meter also fluctuates.
[0018]
Utilizing such fluctuation characteristics of the driving load, it is possible to determine whether or not the critical state has been reached, based on the determination result of the stability determining means for determining whether the power consumption is stable or unstable.
[0019]
Therefore, an experiment for confirming the reproducibility of the fluctuation characteristic of the driving load is also possible.By objectively grasping the critical state, the sliding load monitoring result of the sliding load monitoring means and the optimal The causal relationship with the state is grasped in advance by an experiment, and the control means based on an empirical rule can set and maintain a state slightly exceeding the critical region humidity, and can easily maintain the mirror finishing device in an optimum state. .
[0020]
The invention according to claim 4 is characterized in that at least one of a grindstone, an abrasive pad, a polishing tape, and a polishing sheet is used as the grinding means. Mirror finishing equipment, and its use as a mirror finishing tool for machining workpieces of complex shapes other than surface grinding machines is widely spread.
[0021]
The invention according to claim 5 is the mirror finish device according to any one of claims 1 to 4, wherein the grinding means is applied to a CMP (Chemical Mechanical Polishing) device. Since the mirror finishing device minimizes or eliminates the use amount of the polishing slurry, the polishing slurry, the polishing slurry supply mechanism, and the waste liquid treatment function are also minimized or unnecessary. Therefore, both equipment costs and operation costs can be saved, and the burden on the environment due to waste liquid treatment can be reduced.
[0022]
The invention according to claim 6 is the mirror finishing device according to any one of claims 1 to 5, wherein an oxide material is used as the grinding means. As the material of the oxide, for example, fumed silica, precipitated silica, colloidal silica, fused silica, condensed silica, synthetic silica, silica gel, artificial quartz, the above-mentioned grinding means using at least one kind of porous silica, a mirror surface It is suitable as the grinding means which does not lower the finishing efficiency. Also, the abrasive grains are preferably spherical.
[0023]
Here, combinations of the oxide abrasive grains (right) optimal for the work (left) using various materials are exemplified below.
(A) Quartz: Fe₃O₄
(B) Si: BaCo₃  , CaCO₃
(C) Si₃N₄  : Cr₂O₃
(D) Fe₂O₃  : Fe₃O₄
(E) AlO₃  : SiO₂  , Fe₂O₃  , Fe₃O₄
(F) Si₃N₄  : CaCO₃  , MgO, SiO₂  , Fe₂O₃  , Fe₃O₄
(G) Glass: CeO₂
(H) SiC: Cr₂O₃  , Al₂O₃
(I) AlN: Cr₂O₃
(Nu) ZrO₂  : SiO₂  , CeO₂
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of a mirror finishing device according to an embodiment of the present invention, and a block diagram illustrating a control unit 40. In FIG. 1, for example, a work piece 10 obtained by slicing a cylinder of silicon single crystal into a thin disk shape, rough-grinding and finish-grinding is placed on a rotary table 20, held by vacuum suction, and moved in the direction of arrow J every minute. It rotates at about 10 to 150 rotations.
[0025]
Attached to a grindstone holder (hereinafter, also simply referred to as a “holder”) 32 that is supported by a rotation axis Z2 of a spindle head that is disposed in parallel with the rotation axis Z1 of the turntable 20 at a position separated by a length of the rotation radius. The mechanochemical grindstone (hereinafter, also simply referred to as “grindstone”) 30 is brought into sufficient surface contact with the work 10 on the rotary table 20 so that the mechanochemical grindstone 30 passes through the center of the work 10. It is arranged in a positional relationship so as to cover partly.
[0026]
Then, while the mechanochemical grindstone 30 is rotated in the direction of the arrow K by the motor M on a part of the grinding surface 11 of the rotating work 10, the lower grindstone surface 31 slidably contacts a part thereof, and The entire surface 11 to be ground is ground.
[0027]
Also, in order to appropriately bring the surface 11 to be ground into sliding contact with the grindstone surface 31, and so that the work 10 is intermittently placed, sucked, held, and released on the rotary table 20 in accordance with the progress of the grinding process. At least one of the turntable 20 and the mechanochemical grindstone 30 fixed to the lower end surface of the spindle of the spindle head has an elevating mechanism (not shown) that can move up and down in the axial direction.
[0028]
That is, the distance between the table surface and the grindstone surface 31 of the rotary table 20 is greatly widened, and the work 10 is set between the table surface and the grindstone surface 31 so that the work 10 is inserted. Grinding with gentle pressing force. The rotation of each of the turntable 20 and the mechanochemical grindstone 30 is appropriately controlled.
[0029]
Further, a humidity sensor 9 composed of a dry / wet reaction element exhibiting an electric resistance corresponding to the humidity of the mechanochemical grindstone 30 is fitted on the inner periphery of the mechanochemical grindstone 30, and inputs humidity information to the control means 40. The humidity management unit 42 is configured to operate properly. In addition to the humidity management means 42, the control means 40 measures the power consumption of the drive motor for rotating the mechanochemical grindstone 30, and monitors the drive motor power consumption P. When the monitored power consumption fluctuates, the The situation is compared with the control information stored in the memory 44 to act on the control target setting means 41 to appropriately select the air or the mist 21 from the humidity management means 42 for at least one of the grindstone surface 31 or the ground surface 11. And spray.
[0030]
Note that the humidity sensor 9 is a constituent element for the purpose of clearly explaining the control purpose of the humidity management unit 42. Even when the humidity sensor 9 is not actually used, the driving motor power consumption meter which is a sliding load monitoring unit is used. The humidity management unit 42 can be appropriately operated based on P and the determination result of the stability determination unit 43.
[0031]
FIG. 2 is an index graph showing the state of the mechanochemical grindstone 30 in the control means of the mirror finisher shown in FIG. 1, and FIG. 2 (a) shows the correlation between the humidity (horizontal axis) and the power consumption of the drive motor, FIG. 3B is a graph showing a correlation between humidity and grinding quality. 2, the horizontal axis indicates the humidity of the mechanochemical grindstone 30 (see FIG. 1), and the vertical axis indicates that the operating state of the mirror finishing device changes in response to the change in humidity. The grinding quality and efficiency of grinding can be numerically displayed by, for example, the degree of occurrence of scratches and the cutting speed, but the grinding quality and efficiency are used as indices rather than strictly measured values.
[0032]
The state of the mechanochemical grindstone 30 at each of the indexes 1 to 8 shown in FIG. The index 1 indicates that the mechanochemical grindstone 30 is completely dried and stable when its humidity is, for example, about 0% (since it is not air, it is not a humidity in% display in weather observation and the like, but a mere reference and not shown). It shows the grinding quality and efficiency that can be obtained.
[0033]
Then, the control target setting unit 41 (see FIG. 1) is urged to humidify, and the mist 21 is sprayed from the humidity management unit 42 on at least one of the grindstone surface 31 and the ground surface 11. Then, the state shown by the indices 7 to 8 changes, and the humidity at which the mechanochemical grindstone 30 is completely immersed in water is, for example, about 100% (not shown), and the chemical action of the mechanochemical grindstone 30 is water. And reduce the grinding efficiency to an impractical level.
[0034]
The dry-type mechanochemical mirror-finish whetstone, which is the premise of the present invention, minimizes the wetting of the silica itself due to the water absorption of the PVA resin surrounding the silica of the mechanochemical whetstone 30 based on PVA (polyvinyl alcohol) resin. It is said that it is possible to maintain a high mechanochemical effect, and in general, the mechanochemical grindstone 30 is used after being dried. It was found that the highest level of grinding quality and grinding efficiency indicated by index 7 could be obtained.
[0035]
However, if the humidity of the mechanochemical grindstone 30 is increased beyond the index 2, the situation rapidly deteriorates from the index 3 and falls into an unpractical region indicated by the indexes 4 and 5. In the indices 4 and 5, the balance of the water absorption of the PVA resin surrounding the silica of the mechanochemical grindstone 30 is broken, so that the PVA resin becomes brittle and easily broken, and the silica particles cannot be retained and are separated from the mechanochemical grindstone 30. Since the work 10 is scratched, it becomes impractical.
[0036]
At this time, the drive motor power consumption W shown in FIG. 2 (a) exhibits an unstable fluctuation 45 in the range of Δ1 and Δ2 around W. The cause of the fluctuation 45 is that the PVA resin that holds the silica of the mechanochemical grindstone 30 collapses, the sliding friction resistance between the ground surface 11 of the work 10 and the grindstone surface 31 becomes unstable, and the grindstone holder becomes unstable. This is because the drive motor power consumption W also changes in accordance with the change in the load for rotating the motor 32. Regarding this unstable and impractical state, let the humidity relating to the index 3 be α, and let the humidity relating to the index 6 be β, and let the humidity of the areas α to β be referred to as critical area humidity for convenience of explanation.
[0037]
Then, when the humidity of the mechanochemical grindstone 30 is further increased from the index 5, the situation rapidly recovers from the index 5 to the index 6. The index 7 shows a situation in which the grinding quality and efficiency are maximized at the "humidity slightly exceeding the critical state" described in claim 2. Further, if the mechanochemical grindstone 30 is wet with a high humidity exceeding the index 7, the area falls into a low-efficiency and impractical area along the downward slope shown in the indexes 7 to 8. Conversely, even if the mechanochemical grindstone 30 is gradually wetted from the state of the index 8 where it is completely wet, the situation changes in the order indicated by the indexes 8 to 1.
[0038]
From the above results, the control target 40 automatically controls the humidity management unit 42 so that the control target setting unit 41 (FIG. 1) sets the target of the humidity X that achieves the condition of the index 7 that maximizes the grinding quality and efficiency. Control. This will be specifically described with reference to FIGS.
[0039]
The critical area humidity α to β is a so-called dangerous area, and it is necessary to detect and avoid it quickly. Therefore, the mechanochemical grindstone 30 as a grinding means is rotated by the drive motor M via the grindstone holder 32. A driving motor power consumption meter P as a sliding load monitoring means for monitoring a sliding load, and a stability as a critical detection means for detecting a state in which the sliding load monitored by the sliding load monitoring means fluctuates unstablely. The determination result of the determination means 43 is used.
[0040]
The above-mentioned sliding load monitoring means and criticality detecting means can grasp the correlation shown in the graph of FIG. The experimental data of the situation in which the fluctuations 45 between the heights, the humidity X, α to β of the mechanochemical grinding wheel 30 and the grinding quality and efficiency change from index 1 to index 8 are organized into a “reproducible causal relationship” and stored in memory. 44.
[0041]
The control means 40 is mainly constituted by a microcomputer, in which an arithmetic program stored in a memory 44 stores the above-mentioned experimental data, the control target setting means 41, the stability determination means 43, and each output value of the humidity sensor 9. And the humidity management unit 42 is automatically controlled so as to realize the target humidity X set by the control target setting unit 41.
[0042]
For example, if the control means 40 determines that the condition of the index 1 is present, the mist 21 is blown out to both the ground surface 11 and the grindstone surface 31 of the work 10 by the humidity management means 42 to humidify and drive motor consumption. The critical humidity X is realized by promptly passing the critical region humidities α to β while confirming the fluctuation 45 by the wattmeter P. The control target X is “humidity slightly exceeding the critical state” described in claim 2, and a specific example of the “control target setting means that sets an optimal state adjacent to the critical state as a setting target” described in claim 3 is described below. It shows the effect.
[0043]
The control in the direction indicating the status change in the order of the indexes 1 to 7 is for convenience of explanation, and it is practically impossible to control in the direction indicating the status change in the order of the indexes 8 to 7 in practice. It is convenient because it does not pass through a critical region humidity α to β. In this case, the control means 40 compares and examines the output value of the humidity sensor 9 with the above-mentioned experimental data, and the humidity control means 42 makes the humidity control means 42 dry at least one of the ground surface 11 and the grindstone surface 31 of the work 10. The air 21 is blown out to achieve the target humidity X.
[0044]
The power consumption of the drive motor power consumption meter P is constantly monitored even during the normal operation, and when the power consumption fluctuates, the state including the determination result of the stability determination means 43 is stored in the control information stored in the memory 44. By acting on the control target setting means 41 and appropriately selecting and blowing air or mist 21 from the humidity management means 42 to at least one of the grindstone surface 31 and the ground surface 11, the target humidity is controlled. Keep X.
[0045]
FIG. 3 is a schematic cross-sectional view and a block diagram of a mirror finishing apparatus in which the present invention is applied to a CMP apparatus. In the mirror finisher shown in FIG. 3, the positional relationship between the rotary table 20 and the grindstone holder 32 shown in FIG. 1 is turned upside down, and the rotary table 20a holding the work 10 is disposed above and the urethane pad 30a containing silica is disposed on the upper surface. The configured grinding wheel holder 32a is located below.
[0046]
In the case of the mirror finishing device shown in FIG. 3, the output value of the humidity sensor 9a is input to the control target setting means 41, and is compared with the target value. The target humidity is achieved by appropriately selecting and spraying air or mist 21 on at least one surface of 31a.
[0047]
The well-known silica-containing urethane pad 30a uses a polishing slurry (hereinafter, also simply referred to as "slurry") as a lubricating abrasive in which silica particles are mixed in a paste-like aqueous solution between the grindstone surface 31a and the surface 11 to be ground. While lubricating, maintain high grinding quality and grinding efficiency of mirror finish.
[0048]
However, since the slurry is expensive and has a burden on the environment during waste treatment, it is desirable to reduce the amount of use as much as possible. However, as a lubricating abrasive instead of this slurry, the inventor of the present application has set the grinding wheel surface 31a of the silica-containing urethane pad 30a. By controlling the humidity to a certain degree by the humidity control means 42 and appropriately controlling the humidity, the silica particles separated from the grindstone surface 31a by a small amount are mixed with the applied water to form a paste-like lubricating abrasive. Therefore, equivalent grinding quality and efficiency can be obtained without adding the expensive slurry.
[0049]
4 is a schematic cross-sectional view of a ground surface of a silica-containing urethane pad used in the CMP apparatus shown in FIG. 3, wherein FIG. 4A is an enlarged cross-sectional view in a dry state, and FIG. 4 is an enlarged view of a portion F shown in FIG.
[0050]
As shown in FIG. 4A, the silica-containing urethane pad 30a is configured based on a PVA resin 34 in which silica particles 33 are mixed as abrasive grains, and the PVA resin 34 has a porous structure including the pores 22. The bubbles 22 can contain a certain amount of moisture like a sponge.
[0051]
As shown in FIG. 4B, in order to maintain the quality and efficiency of the mirror finish, the slurry is used in combination with a lubricant, but the boundary between the outer peripheral surface of the silica particles 33 and the PVA resin 34 and the pores 22 are formed. It is estimated that the state where the water film 23 remains thin on the inner wall surface is one of the conditions for obtaining the highest grinding quality and efficiency shown in FIG.
[0052]
For example, in order to maximize the mechanochemical phenomenon (i.e., the chemical reaction of the minute unit induced by the applied mechanical energy) that occurs in the h between the soft abrasive grains and the workpiece even in the case of a dry-type mirror finishing device. In addition to maintaining a very small amount of moisture or moderate humidity effectively, the surface roughness due to cohesive wear can be prevented by a lubrication effect close to that of the slurry during mirror finishing.
[0053]
In addition, as shown in FIG. 4B, the amount of water that oozes out from the vicinity of the grinding contact point 35 of the water film 23 to the surface 11 to be ground of the work 10 is limited to a very small cross section of the water film 23. In the case of using water as the washing cooling medium or the above-mentioned slurry mainly composed of water, harm of water wetting can be avoided. Since the mirror finishing device minimizes or eliminates the use amount of the polishing slurry, the polishing slurry, the polishing slurry supply mechanism, and the waste liquid treatment function are also minimized or unnecessary. Therefore, both equipment costs and operation costs can be saved, and the burden on the environment due to waste liquid treatment can be reduced.
[0054]
Therefore, according to the present invention, it is possible to achieve both a mirror finish and a work that is resistant to water wetting. For example, a mirror-finished surface of sodium chloride, which is cut from a single crystal of sodium chloride, which is a water-soluble material, to form an infrared prism, or a mirror-finished surface of a workpiece made of a substance that generates a toxic gas by chemically reacting with water , Etc., against the property that dislikes water wetting, etc., without using the slurry mainly composed of water, with a lubricating effect close to that slurry, preventing surface roughness due to cohesive wear, maximizing grinding quality and efficiency Thus, it is possible to achieve both of obtaining the mirror surface and finishing the mirror surface with a property of being resistant to water wetting. In this case, the control target setting unit 41 shown in FIG. 1 is set to be slightly dry, and the humidity management unit 42 blows the slightly dried air 21.
[0055]
Regarding the above-mentioned sodium chloride, more specifically, since ordinary anhydride crystals are colorless and equiaxed hexahedrons and transmit infrared rays well, large single crystals are used for prisms of infrared spectrometers.
Unpurified sodium chloride is unusable because it contains magnesium and calcium salts and shows deliquescence, but pure sodium chloride does not have deliquescence and is water-soluble. In consideration of the above, the method can be put into practical use by polishing and devising so as not to get wet with water.
[0056]
In addition, for example, it is generally called “grinding” for a semiconductor wafer and “polishing” for lenses, prisms and jewelry, but “grinding” of the grinding means of the present invention. Means a process using a tool in which abrasive grains are fixed by a binder, and "polishing" is used in the same meaning as long as it is a process corresponding to the process.
Therefore, the mirror finishing device of the present invention is also suitable for polishing jewelry such as sapphire. However, description of the mechanism design is omitted.
[0057]
The grindstone is not limited to a donut (annular) shape, and a disc surface may be used as a grindstone surface. The mechanochemical grindstones 30 and 30a and the turntable 20 may be located in any of the upper and lower directions. .
[0058]
In addition, the water absorption of PVA surrounding the silica of the mechanochemical grindstone 30 can minimize the wetting of the silica itself and maintain a high mechanochemical effect. It is not necessary to limit to silica in order to exhibit the mechanochemical effect. Further, as the material of the "oxide" used for the abrasive grains of the grinding means, for example, at least one of fumed silica, precipitated silica, colloidal silica, fused silica, condensed silica, combustion synthetic silica, silica gel, artificial quartz, and porous silica The grinding means using a type is suitable as the grinding means which does not reduce the efficiency of mirror finishing. Also, the abrasive grains are preferably spherical.
[0059]
The cleaning and cooling medium is not a mist of pure water, but may be a mist mixed with oil or other liquid, pure water or other liquid may be applied as it is, and the grinding stone is not limited to a cup-shaped one. Alternatively, the entire lower surface of the disk may be a grindstone surface.
Further, in the embodiment, water is applied from the outer peripheral side of the annular (cup-shaped) grindstone, but water may be applied from the inner peripheral side of the annular grindstone.
[0060]
Further, the grinding means is not limited to a surface grinder using a rotary grindstone or the like, but is applied to a mirror finishing device using at least one of a grindstone, an abrasive pad, a polishing tape, and a polishing sheet. The use of the grinding means as a polishing tool is widespread.
[0061]
These are abrasive grains formed on the surface of a platen (platen) that moves in an eccentric small circle (orbital), instead of a surface grinding machine that combines a rotating whetstone that moves in a single rotation and a work holder that sucks a work. A method of using a work holder with a work sucked down on the ground surface of the pad, or a polishing tape of a belt conveyor type, a partial contact scanning process with an annular semi-fixed hard pad of a rotary scanning type, a cylindrical pad that rotates, Alternatively, the present invention is applied to a mirror finishing device using any tool (pad) of a polishing sheet.
[0062]
A precision mechanical device that is applied to a mirror finishing device using any of the tools (pads) described above, and that appropriately rotates, rotates, revolves, swings, or reciprocates (linearly) a rotating grindstone or a work. The devices having the configurations described in Japanese Patent Application Laid-Open No. 2001-71242, JP-A-2001-246557, JP-A-2001-32256, JP-A-2001-358106, JP-A-3-104536, and JP-A-4-141336 can be realized by designing by those skilled in the art. Further illustration and explanation are omitted because they are considered.
[0063]
Note that the present invention can be variously modified within the scope of the technical idea, and various embodiments other than the above-described embodiment are conceivable. In these, as described in claim 1, in a mirror finishing device provided with a grinding means accompanied by a chemical action, a humidity for managing the humidity of at least one of the ground surface of the grinding means and the surface to be ground of the work. Naturally, all the cases belonging to the present invention belong to the present invention.
[0064]
【The invention's effect】
As described above, according to the first aspect of the present invention, the grinding means having a chemical action makes the ground surface brittle at a critical region humidity between the dry state and the wet state, and Since a scratch is generated on the ground surface and there is a critical state that is considered to be unsuitable for practical use, the humidity management unit sets the ground surface of the grinding unit and at least one of the surfaces to be ground of the work to the optimum humidity. If maintained, the critical state can be avoided.
[0065]
Further, since the humidity slightly exceeding the critical region humidity is in an optimum state for maximizing the operation efficiency and the production quality of the mirror finishing device, if the humidity management means sets and maintains the optimum humidity, You can achieve your goals.
[0066]
According to the invention according to claim 2, a causal relationship between the sliding load monitoring result of the sliding load monitoring means and the optimum state is grasped in advance by an experiment, and the control means dries the sliding load slightly more than the critical region humidity. By setting and maintaining the set humidity, the optimum state can be stably and easily maintained.
[0067]
According to the invention according to claim 3, it is determined whether or not the critical state has been reached, based on the determination result of the stability determining means for determining whether the power consumption is stable or unstable by using the fluctuation characteristics of the driving load. Can be determined.
[0068]
Therefore, the optimum state can be easily maintained by setting and maintaining a state in which the humidity is slightly dried from the critical area humidity by the control means that is grasped in advance through experiments and is based on empirical rules.
[0069]
According to the invention according to claim 4, the use as a mirror finishing tool for machining a work having a complicated shape other than the surface grinder is widespread.
[0070]
According to the fifth aspect of the present invention, the amount of the polishing slurry used is minimized or unnecessary, so that the polishing slurry, the polishing slurry supply mechanism, and the waste liquid treatment function are also minimized or unnecessary. Therefore, both equipment costs and operation costs can be saved, and the burden on the environment due to waste liquid treatment can be reduced.
[0071]
According to the invention of claim 6, as the oxide material, for example, at least one of fumed silica, precipitated silica, colloidal silica, fused silica, condensed silica, synthetic silica, silica gel, artificial quartz, and porous silica Is suitable as the grinding means which does not reduce the efficiency of mirror finishing.
[0072]
Then, various combinations of oxide abrasive grains (right) optimal for the work (left) using various materials can be selected.
(A) Quartz: Fe₃O₄
(B) Si: BaCo₃  , CaCO₃
(C) Si₃N₄  : Cr₂O₃
(D) Fe₂O₃  : Fe₃O₄
(E) AlO₃  : SiO₂  , Fe₂O₃  , Fe₃O₄
(F) Si₃N₄  : CaCO₃  , MgO, SiO₂  , Fe₂O₃  , Fe₃O₄
(G) Glass: CeO₂
(H) SiC: Cr₂O₃  , Al₂O₃
(I) AlN: Cr₂O₃
(Nu) ZrO₂  : SiO₂  , CeO₂
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a mirror finishing device according to an embodiment of the present invention, and a block diagram illustrating a control unit.
FIG. 2 is an index graph showing a state of a mechanochemical grinding wheel in a control means of the mirror surface finishing device shown in FIG. 1, wherein FIG. 2 (a) shows a correlation between humidity and drive motor power consumption, and FIG. 2 (b). Is a graph showing the correlation between humidity and grinding quality.
FIG. 3 is a schematic cross-sectional view and a block diagram of a mirror finishing apparatus in which the present invention is applied to a CMP apparatus.
4 is a schematic cross-sectional view of a ground surface of a silica-containing urethane pad used in the CMP apparatus shown in FIG. 3, wherein FIG. 4A is an enlarged cross-sectional view in a dry state, and FIG. It is an enlarged view of F part shown to a).
[Explanation of symbols]
1-8 Index indicating the status of mechanochemical grinding wheels
9,9a Humidity sensor
10 Work
11 Surface to be ground
20,20a Rotary table
21 Air or mist
22 pores
23 Water film
30, 30a Mechanochemical whetstone
31, 31a Whetstone surface
32, 32a Whetstone holder
33 silica particles
34 PVA resin
35 Grinding contacts of silica particles
40 control means
41 Control target setting means
42 Humidity control means
43 Stability determination means
44 memory
45 turbulence
P wattmeter
W Drive motor power consumption
Z1, Z2 rotation axis
α, β Critical region humidity
Δ1, Δ2 Range under turbulence

Claims (6)

In a mirror finishing device provided with a grinding means with a chemical action,
A mirror finishing device comprising: a humidity control unit that controls humidity of at least one of a ground surface of the grinding unit and a ground surface of a workpiece. As the humidity management means,
Sliding load monitoring means for monitoring the sliding load of the grinding means,
Criticality detection means for detecting a state in which the sliding load monitored by the sliding load monitoring means is unstable and fluctuates,
The mirror surface according to claim 1, further comprising control means for setting and maintaining the humidity in an optimum state adjacent to the critical state detected by the criticality detecting means and slightly exceeding the critical state. Finishing equipment. As the sliding load monitoring means,
A drive motor power meter that measures the power consumption of the drive motor that drives the rotating grindstone,
Stability determining means for determining whether the power consumption is stable or unstable;
A control target setting unit that sets the critical state when the determination result of the stability determination unit becomes unstable, and sets an optimal state adjacent to the critical state as a setting target, as the control unit; The mirror finishing device according to claim 1 or 2, wherein The mirror finishing device according to any one of claims 1 to 3, wherein at least one kind of a grindstone, an abrasive pad, a polishing tape, and a polishing sheet is used as the grinding means. The mirror finishing device according to any one of claims 1 to 4, wherein the grinding means is applied to a CMP device. The mirror finishing device according to any one of claims 1 to 5, wherein an oxide material is used as the grinding means.

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