JP3830619B2 - Method and apparatus for recycling recycling used composition of lapping machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recycling method and a recycling apparatus for a used composition which regenerates a used composition used in a lapping apparatus and supplies the regenerated used composition to a lapping apparatus.
[0002]
Here, the used composition refers to a composition used when lapping various industrial products such as semiconductors, memory hard disks, photomasks, crystal and ferrite, or members thereof. More specifically, used compositions used in lapping for polishing silicon wafers, gallium arsenide wafers and other semiconductor substrates, aluminum, glass, etc. and various other memory hard disks, photomasks, crystal and ferrite single crystals. Can be used to play.
[0003]
[Prior art]
In general, in the lapping process of the free abrasive method, a composition containing an abrasive, various additives and water is used. For example, a silicon wafer which is a semiconductor substrate material is manufactured by chamfering a sliced wafer obtained by slicing an ingot, and then lapping (lapping) and mirror polishing (polishing).
[0004]
For this lapping, GC (green silicon carbide), C (black silicon carbide), FO (trade name, manufactured by Fujimi Incorporated), aluminum oxide and other abrasives, surfactant and lapping Compositions containing various additives such as oil and water are used.
[0005]
For lapping such as aluminum (Al) disk and glass disk, crystal, and phyllite single crystal used for AV (audio visual), computers and other storage devices, GC (green silicon carbide), C ( A composition for lapping (hereinafter referred to as a composition) containing at least one abrasive selected from the group consisting of black silicon carbide), FO, aluminum oxide, and quartz, and various additives and water is used. .
[0006]
The above-mentioned abrasive contained in the composition used in the lapping apparatus is required to have a very excellent particle size distribution in order to obtain a high surface quality of the object to be polished. For this reason, it is said that the abrasive is very expensive and occupies about 30% of the lapping cost, and cost reduction has been demanded. As one of means for achieving a lapping cost reduction, it has been studied to circulate and repeatedly use the composition.
[0007]
On the other hand, used compositions after lapping have been discarded so far for one-time use. For this reason, the wastes by the abrasive etc. in a used composition increase year by year, and the environmental pollution which generate | occur | produces by this was pointed out. As one means for solving this problem, it has been studied to circulate and repeatedly use the composition.
[0008]
However, a part of the abrasive in the composition is refined by crushing and abrasion in lapping and becomes fine abrasive grains. Moreover, the lapping process produces | generates the grinding | polishing waste which is the process waste of a to-be-polished object. Furthermore, iron powder and fine iron powder are generated by lapping iron rust powder or the surface plate itself from the surface plate of the lapping apparatus. For this reason, in the used composition, in addition to the abrasive that is still effective, the fine abrasive grains, polishing scraps, iron rust powder, iron powder and fine iron powder (hereinafter collectively referred to as unnecessary materials) If the composition is circulated and used repeatedly, unnecessary materials that have gradually accumulated in the composition will cause defects such as scratches on the surface of the object to be polished, adversely affecting the quality of the object to be polished. It was a factor that lowered productivity.
[0009]
For this reason, various methods for reusing a used composition have been studied. Japanese Examined Patent Publication No. 7-41535 discloses an abrasive liquid regeneration / circulation device that regenerates a used abrasive liquid and circulates it.
[0010]
The abrasive liquid recycling apparatus disclosed in JP-B-7-41535 reproduces and regenerates the used abrasive liquid that is generated when lapping is performed using an abrasive liquid consisting of only abrasive and pure water. The used abrasive liquid is used as lapping.
[0011]
In recent years, compositions widely used in lapping include abrasives and water, surfactants and lapping for the purpose of promoting lapping, improving the surface condition of objects to be polished, preventing rust on processing equipment surface plates, and other purposes. Various additives such as oil are added.
[0012]
In general, the object to be polished after lapping is often taken out after being sprinkled with water on the surface plate of the lapping machine for the purpose of simple cleaning, and this washing water is mixed into the composition. As a result, the concentration of the abrasive in the composition is lowered, and therefore water in the composition has to be removed for the purpose of adjusting the concentration.
[0013]
Furthermore, since the concentration of various additives is lowered and sufficient action cannot be obtained by adding this cleaning water or adding new abrasive grains and water, it is necessary to add and replenish various additives.
[0014]
However, the regeneration circulation device disclosed in Japanese Examined Patent Publication No. 7-41535 cannot remove the washing water mixed in the composition, and automatically adjusts the concentrations of various additives in the composition. In order to improve productivity, there is room for improvement. In addition, since a number of processes and devices are incorporated between the particle size sorting means and the lapping machine, there is also a problem that scratches occur due to mixing of abrasive grains and foreign matters larger than a predetermined particle size after the particle size sorting. is there.
[0015]
[Problems to be solved by the invention]
The present invention has been made to solve the above-mentioned problems, and polishes silicon wafers, gallium arsenide wafers and other semiconductor substrates, aluminum, glass and other various memory hard disks, photomasks, crystals, and ferrite single crystals. It is possible to cope with the composition to which various additives such as surfactant and lapping oil have been added, which has been conventionally required for lapping, and it is possible to remove unnecessary materials and reuse only effective abrasives. The concentration of water, various additives, and abrasives can be adjusted automatically, making it easy to adjust and regenerate the composition, and immediately supply the regenerated composition to the lapping machine. Is possible. For this reason, productivity can be improved without adversely affecting the surface quality of the object to be polished, and the composition can be effectively used to reduce the lapping cost. It is an object of the present invention to provide a recycling apparatus for used composition recycling of a lapping apparatus and a method for recycling the used composition using the same, which can reduce environmental pollution by reducing the amount.
[0016]
[Means for Solving the Problems]
In the present invention, a used composition which is used in a lapping apparatus and contains unnecessary materials together with an effective abrasive is regenerated in a state where the concentration of the additive in the composition is adjusted, and the regenerated composition is obtained. By supplying to the lapping machine, productivity can be improved without adversely affecting the surface quality of the object to be polished, and it is possible to effectively use the composition and reduce lapping cost. At the same time, environmental pollution can be reduced by reducing the amount of waste composition.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an apparatus for recycling and circulating a used composition of a lapping apparatus according to the present invention. In FIG. 1, the code | symbol 1 shows a lapping apparatus and the code | symbol 2 shows a 1st storage tank.
[0018]
The first storage tank 2 is fed with a used lapping composition in which the effective abrasive used in the lapping apparatus 1 and unnecessary materials are mixed, by ordinary means. Agitation means 3 is installed in the first storage tank 2 to agitate the used composition 4 accommodated in the first storage tank 2. The discharge port 2 a of the first storage tank 2 is connected to a foreign matter removing device 6 through a pipe line 5. A pump 7 which is a means for feeding the used composition 4 is disposed in the middle of the pipe 5.
[0019]
The foreign matter removing device 6 includes a foreign matter removing net 8, a magnet 9 that is an iron removing machine, and a vibration type sieve 10 that is a sieve machine in order from the upstream side. The sieving machine 10 can use an inclined type sieve and other various types of sieves in addition to the vibration type sieve, but considering the problem of clogging of the sieve screen, it is preferable to use the vibration type sieve. .
[0020]
The used composition 4 is obtained by removing foreign matters such as solidified abrasive grains, polishing scraps and iron rust, iron powder, fine iron powder, polishing scraps, and iron rust powder in the foreign matter removing device 6, and as a filtered composition 4a. It is fed to the second storage tank 11. The second storage tank 11 is provided with stirring means 12 for stirring the filtered composition 4a accommodated in the second storage tank 11. The discharge port 11a of the second storage tank 11 is connected to a liquid cyclone 15 that is a cyclone classifier via a conduit 14. A pump 13 serving as a means for feeding the filtered composition 4a is disposed in the middle of the pipeline 14. The pump 13 operates in response to a signal from a liquid amount detection function of the concentration adjustment tank 16 described later. The filtered composition 4 a stored in the second storage tank 11 is fed to the hydrocyclone 15 by a predetermined amount by the pump 13. The filtered composition portion 4 a is fed with water and fine abrasive grains smaller than a predetermined particle size in the liquid cyclone 15 and fed to the concentration adjustment tank 16.
[0021]
Although not shown, the concentration adjustment tank 16 has a control unit having a liquid amount detection function, a weight measurement function, and a water amount calculation function. Further, a water supply device (not shown) is connected to the concentration adjustment tank 16. The water supply device causes the filtered composition 4a to have a predetermined specific gravity based on a control signal from a control unit that detects the amount and weight of the filtered composition 4a fed from the hydrocyclone 15 to the concentration adjustment tank 16. In addition, a necessary amount of water is added to the filtered composition 4 a in the concentration adjustment tank 16. The filtered composition 4a to which water has been added is agitated and mixed by the agitating means 17 installed in the concentration adjustment tank 16 to become a regulated composition 4b having a constant concentration. The discharge port 16 a of the concentration adjustment tank 16 is connected to the third storage tank 19 through a pipe line 18. In the middle of the pipe 18, a pump 20 that is a means for feeding the adjusted composition 4 b is disposed.
The third storage tank 19 is provided with an additive supply device 21, and the additive supply device 21 supplies the additive 22 to the adjusted composition 4 b in the third storage tank 19.
[0022]
The additive supply device 21 includes an additive mixing tank 23 and a stirring unit 24 for stirring the additive raw material stored in the additive mixing tank 23. The additive 22 is formed by stirring the additive raw materials such as wrap oil and surfactant in a predetermined ratio by the stirring means 24. The liquid amount of the adjusted composition 4 b fed from the concentration adjustment tank 16 to the third storage tank 19 is measured by the liquid amount detection function of the control unit added to the concentration adjustment tank 16. Based on the liquid amount detection signal of the control unit, the additive 25 in a certain ratio with respect to the liquid amount of the adjusted composition 4b is connected to the pipeline 26 by the metering pump 25 attached to the discharge port of the additive mixing tank 23. Via the third storage tank 19. The third storage tank 19 is provided with a stirring means 27, and stirs the adjusted composition 4c in which the additive 22 is added to the adjusted composition 4b.
[0023]
The third storage tank 19 and the lapping apparatus 1 are connected via a conduit 28. In the middle of the conduit 28, a pump 29, which is a feeding means for the adjusted composition 4c, and a filter 30 for removing foreign matters larger than a predetermined particle size are installed.
[0024]
Further, an abrasive supply device (not shown) is connected to an arbitrary process after the liquid cyclone 15 and before the filter 30. The abrasive material supply device measures a new abrasive material and adds and mixes it to the composition so that the composition in each step has a predetermined specific gravity.
[0025]
The adjusted composition 4c, to which new abrasive has been added and foreign matter has been removed by the filter 30, is fed to the lapping apparatus 1 as a recycled composition.
[0026]
In addition, in an arbitrary process from the first storage tank 2 to the lapping apparatus 1, for the purpose of increasing the removal accuracy of solidified abrasive grains, foreign matters such as polishing scraps and iron rust, iron powder, polishing scraps and iron rust powder, In addition to the foreign matter removal net 8 and the filter 30, it is also possible to add a filter, a foreign matter removal net or an iron removing machine.
[0027]
Furthermore, by incorporating an ultrasonic oscillator in the previous process of the filter or the foreign substance removal network, the foreign substance removal device 7 and the filter 30 or in these processes, and improving the dispersibility of the composition, It is also possible to prevent clogging.
[0028]
The type of filter is not particularly limited as long as it does not impair the effects of the present invention. The filter 30 and the filter that can be installed during any step of the present invention can be provided with a backwash device for the purpose of preventing clogging.
[0029]
Moreover, in the process from the lapping apparatus 1 to the second storage tank 11, it is also possible to add a device that defoams by applying water or the like as a countermeasure against bubbles caused by various additives contained in the composition. .
[0030]
Furthermore, in the present invention, a pump is used as a feeding means between processes. However, a head between processes may be provided instead of the pump, and feeding may be performed using this head.
[0031]
Next, the operation will be described.
[0032]
When lapping of the semiconductor substrate, memory hard disk, photomask, crystal, and ferrite single crystal is performed in the lapping apparatus 1, the composition used in the lapping apparatus 1 is used as the used composition 4 in the first storage tank. 2 are collected and stored. The used composition 4 still contains unnecessary abrasives as well as effective abrasives.
[0033]
Subsequently, when the pump 7 provided in the pipe line 5 connecting the first storage tank 2 and the foreign matter removing device 6 is operated, the used composition 4 stored in the first storage tank 2 is supplied to the foreign matter removing device 6. Is done. The foreign matter removing device 6 includes a foreign matter removing net 8, a magnet 9 that is an iron removing machine, and a vibration type sieve 10 that is a sieving machine in order from the upstream side. The composition 4 has foreign matters larger than a predetermined particle size contained in the used composition 4, such as solidified abrasive grains, polishing scraps, and iron rust, removed by the foreign matter removal net 8, and is contained in the used composition 4 by the magnet 9. The iron dust and fine iron powder to be removed are contained in the used composition 4 by the vibration type sieve 10 and cannot be removed by the foreign matter removing net 8. Foreign matter is removed. The filtered composition 4a from which foreign matter, iron powder, and the like have been removed in the foreign matter removing device 6 is collected and stored in the second storage tank 11.
[0034]
Subsequently, when the pump 13 provided in the pipe line 14 connecting the second storage tank 11 and the liquid cyclone 15 as the cyclone classifier operates, the filtered composition 4a collected in the second storage tank 11 is converted into the liquid cyclone 15. To be sent to. The pump 13 operates in response to a signal from the liquid amount detection function of the control unit connected to the concentration adjustment tank 16.
[0035]
The filtered composition 4a fed to the hydrocyclone 15 is separated into water, fine abrasive grains smaller than a predetermined grain size, and abrasive grains larger than a predetermined grain size in the liquid cyclone 15, leaving abrasive grains larger than a predetermined grain size. And fine abrasive grains smaller than a predetermined grain size are removed. The filtered composition 4 a containing abrasive grains having a predetermined particle size or more is fed to the concentration adjustment tank 16.
[0036]
The filtered composition 4a containing abrasive grains of a predetermined particle size or more to be fed to the concentration adjustment tank 16 is measured for the amount of liquid by the liquid amount detection function of the control unit attached to the concentration adjustment tank 16, and the weight is measured by the weight measurement function. The amount of water required to adjust the filtered composition 4a to a predetermined specific gravity is calculated based on the liquid volume and weight values of the filtered composition 4a by the water amount calculation function. The control unit sends a signal calculated by the water amount calculation function to the water feeding device, the water feeding device is activated, and the amount of water obtained by the water amount calculating function from the water feeding device to the concentration adjustment tank 16. To send.
[0037]
That is, the control unit measures the liquid amount of the filtered composition 4a supplied to the concentration adjustment tank 16 by the liquid amount detection function, and when the predetermined amount of the filtered composition 4a is supplied, the pump 13 And the supply of the filtered composition 4a to the hydrocyclone 15 is stopped. For this reason, the filtered composition 4a fed to the concentration adjustment tank 16 becomes a constant amount. Next, the weight of the filtered composition 4a fed to the concentration adjustment tank 16 is measured by the weight measurement function. Subsequently, the water amount calculation function calculates the amount of water necessary to prepare the filtered composition 4a at a predetermined specific gravity based on the liquid amount and the weight value. And the quantity of water calculated | required by the water supply apparatus is supplied to the concentration adjustment tank 16 containing the filtered composition 4a. Stirring means 17 is installed in the concentration adjustment tank 16, and the filtered composition 4a to which water has been added is stirred and mixed to obtain an adjusted composition 4b having a predetermined concentration.
[0038]
Next, when the pump 20 provided in the pipe 18 connecting the discharge port 16a of the concentration adjustment tank 16 and the third storage tank 20 is activated, the adjusted composition 4b in the concentration adjustment tank 16 is sent to the third storage tank 19. Be paid. When the supply of the adjusted composition 4b in the concentration adjusting tank 16 to the third storage tank 19 is completed, the above-described pump 13 is activated again, and the filtered composition 4a from the second storage tank 11 to the hydrocyclone 15 is supplied. Feeding is started.
[0039]
The additive supply device 21 is predetermined with respect to the liquid amount of the adjusted composition 4b measured by the liquid amount detection function with respect to the additive 22 in the additive mixing tank 23 by the metering pump 26 operated by a signal from the control unit. An amount corresponding to the ratio is supplied to the third storage tank 19 via the pipe line 26. The third storage tank 19 is provided with a stirring means 27 for stirring the adjusted composition 4c.
[0040]
Subsequently, when the pump 29 provided in the pipe line 28 connecting the third storage tank 19 and the lapping apparatus 1 is operated, the adjusted composition 4 c in the third storage tank 19 passes through the filter 30 provided in the pipe line 28. At this time, after removing the solidified particles larger than a predetermined particle size and foreign matters mixed in the steps after the foreign matter removing device 6, they are fed to the lapping apparatus 1 as a regenerated composition.
[0041]
An abrasive supply device (not shown) is connected to an arbitrary process after the hydrocyclone 15 and before the filter 30. Similar to the water supply device, the abrasive material supply device is provided with a liquid amount measuring function for measuring the liquid amount of the composition in the process and a weight measuring function for measuring the weight thereof. Based on the measured liquid volume and weight values of the composition, an abrasive amount calculation function for calculating the amount of new abrasive necessary to prepare the composition at a predetermined specific gravity, and a new polishing amount of that amount. An abrasive addition function for measuring the material and adding it to the composition is added.
[0042]
As described above, the adjusted composition 4c to which a new abrasive has been added is fed to the lapping apparatus 1 as a recycled composition after removing foreign substances, solidified abrasive grains and the like by the filter 30.
[0043]
【The invention's effect】
As described above, according to the present invention, it can be applied to a composition to which various additives such as a surfactant and wrap oil are added, and iron rust powder, iron powder and fine particles coming out from the lapping apparatus itself. It is possible to remove iron powder, fine abrasive grains worn by abrasives outside the predetermined particle size range, polishing scraps produced by polishing the object to be polished, and each of water, various additives, and abrasives. Since the concentration is adjusted automatically, the composition can be easily adjusted, and the recycled composition can be immediately supplied to the lapping apparatus. Therefore, productivity can be improved without adversely affecting the surface quality of the workpiece, the composition can be used effectively, the lapping cost can be reduced, and the amount of composition discarded can be reduced. By doing so, environmental pollution can be reduced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a method for reclaiming used processing liquid of a lapping apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lapping apparatus 2 1st storage tank 4 Used composition 6 Foreign material removal apparatus 11 2nd storage tank 15 Hydrocyclone 19 Concentration adjustment tank 17 3rd storage tank 21 Additive supply apparatus 22 Additive 30 Filter

Claims (4)

A foreign material removing device for removing foreign matter from a used composition, and a foreign matter removing device for recycling the used composition used in the lapping device and recycling the used composition supplied to the lapping device. A cyclone classifier that classifies the used composition that has been removed, a concentration adjustment tank that adjusts the concentration of the used composition that has been classified with a concentration adjusting means, a tank that stores the concentration-adjusted used composition, An additive supply device for supplying an additive to the stored used composition, and an additive supplied from the additive supply device in accordance with the detected amount of the used composition stored in the tank. a control device for controlling the amount of lapping apparatus characterized by having a defoaming device for defoaming a foaming by additives contained in the used compositions used sets Things of playback circulation apparatus.   2. The recycling apparatus for used composition according to claim 1, wherein the foreign matter removing device comprises a foreign matter removing net, an iron remover, and a sieve.   The recycling apparatus for recycling a used composition according to claim 1, wherein the cyclone classifier is a liquid cyclone. In the recycling method of the used composition used in the lapping machine, the foreign material is removed from the used composition used in the lapping machine in a method for recycling the used composition used in the lapping machine. The step of removing foreign substances from the used composition or the step of eliminating foaming caused by additives, the step of classifying the used composition from which foreign substances have been removed, and the concentration of the used composition after classification. A step of adjusting, a step of automatically supplying an additive in an amount corresponding to the amount of the used composition whose concentration is adjusted to a concentration-adjusted used composition, and a used composition that is regenerated by supplying the additive And a step of returning the product to the lapping apparatus.

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