JP2002233954A - Slurry feeding method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of a slurry tank, the size of a temperature adjusting means, and thermal capacity of the temperature adjusting means, and to enable continuation of processing of a wafer during supply of slurry. SOLUTION: Slurry is circulated between a slurry tank and a temperature adjusting means to adjust the temperature of slurry and the slurry is fed to a wafer polishing device. An amount of slurry fed to the device is detected and slurry in an amount equivalent to the detecting amount is supplied to the tank. The sizes of the slurry tank and the temperature adjusting means can be reduced and heat capacity of the temperature adjusting means can be reduced. Even during supply of slurry, processing of the wafer can be continued. Further, a difference amount between a slurry supply amount and a return amount can be supplied. Recovery and reutilization of the slurry are practicable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slurry supply method and a slurry supply method, more specifically, a lapping apparatus, a polishing apparatus,
The present invention relates to a slurry supply method and an apparatus for supplying slurry to semiconductor wafer manufacturing equipment including CMP, hard disk manufacturing equipment, substrate manufacturing equipment, and the like.

[0002]

2. Description of the Related Art Etched silicon wafers are:
In the next polishing step, the surface is mechanically and chemically polished. Here, a polishing apparatus is used to finish the surface of the wafer to a smooth and non-distorted mirror surface. 2. Description of the Related Art Conventionally, as one type of polishing apparatus, a single wafer type wafer polishing apparatus for polishing a surface of a silicon wafer one by one has been known. This single wafer type wafer polishing apparatus has a polishing platen on which a polishing cloth is spread on an upper surface, a polishing head arranged opposite to and above the polishing platen, and is detachably attached to the polishing head. And a disc-shaped carrier plate to which the silicon wafer is attached. At the time of single wafer polishing of a silicon wafer, an abrasive (slurry) containing free abrasive grains such as colloidal silica (silica sol) is supplied onto a polishing cloth through a nozzle by a slurry supply device, and the polishing cloth and the silicon wafer are separated. Apply a predetermined load and relative speed between
A single silicon wafer is polished.

[0003] The abrasive in the circulation tank provided in the slurry supply device is pressure-fed to the nozzle by the operation of a slurry pump connected to a slurry supply pipe. In the middle of the slurry supply pipe, a heat exchanger (temperature control means) for raising the temperature of the abrasive to a predetermined temperature (30 ° C.) before being supplied to the wafer polishing apparatus, and a valve for closing the flow path of the slurry supply pipe And are connected in order toward the downstream. Further, a base of a slurry return pipe for returning the abrasive to the circulation tank until the abrasive reaches a set temperature is connected between the heat exchanger and the valve of the slurry supply pipe. as a result,
When the temperature of the abrasive is raised, a closed circulation loop of the abrasive is formed between the circulation tank, the upstream portion of the slurry supply pipe from the valve installation position, and the slurry return pipe by closing the valve. Will be.

[0004]

By the way, in this conventional slurry supply apparatus, the abrasive is not supplied to the circulation tank until the abrasive stored in the circulation tank is almost completely used. As a result, in order to avoid interruption of the polishing operation of the silicon wafer, the circulation tank generally uses a large tank of 100 liters or more.
As a result, the total amount of the abrasive circulating in the circulation loop increases, and it is necessary to provide a large heat exchanger. Moreover, in order to heat a large amount of the abrasive to the set temperature, a wasteful amount of heat is consumed when heating the heat medium supplied to the heat exchanger. In addition, since the replenishment of the polishing agent is not performed unless the circulation tank is almost empty, the polishing agent cannot be supplied to the wafer polishing apparatus at the time of the replenishment of the polishing agent. I was

Therefore, as a result of earnest research, the inventor of the present invention has found that if the amount of the abrasive used is replenished to the circulation tank as needed, the total amount of the abrasive circulated in the circulation loop decreases, and We found that it was possible to reduce the size of the tank and the heat capacity of the heat exchanger, to suppress the heat capacity required for raising the temperature of the abrasive, and to eliminate interruption of wafer polishing work when replenishing the abrasive. Thus, the present invention has been completed.

[0006]

The object of the present invention is to reduce the size of a slurry tank,
A slurry supply method capable of reducing the size of the temperature control means and reducing the heat capacity of the temperature control means, suppressing the heat capacity required for controlling the temperature of the slurry, and continuing the processing of the wafer even when replenishing the slurry. And the provision of such a device.

[0007]

According to a first aspect of the present invention, there is provided a slurry tank for storing a slurry containing loose abrasive grains, and a temperature adjusting means for adjusting the temperature of the slurry discharged from the slurry tank. Supplying a slurry to a facility using the slurry in a slurry supply method including a step of adjusting the temperature of the slurry while circulating the slurry between the slurry and a step of supplying the slurry after the temperature control to the facility using the slurry. This is a slurry supply method in which the amount of the slurry after the temperature adjustment is detected, and the same amount of the slurry as the detected amount is supplied to the slurry tank as needed.

[0008] The equipment using slurry includes a semiconductor wafer manufacturing apparatus, CMP, a substrate manufacturing apparatus, a hard disk manufacturing apparatus, and the like. More specifically, an ingot cutting device such as a wire saw, a semiconductor wafer wrapping device,
Examples include a PCR processing device for polishing a chamfered surface of an outer peripheral portion of a semiconductor wafer, a device for grinding a surface of a semiconductor wafer, and a polishing device for polishing a surface of a semiconductor wafer. The type of slurry is not limited. Usually, the type of slurry and the mixing ratio of various components constituting the slurry are determined by the manufacturing equipment to which the slurry pipe communicates. For example, in the case of a wafer polishing apparatus, the slurry becomes an abrasive.
As the abrasive, for example, a mixture of calcined silica, colloidal silica (free abrasive), amine (processing accelerator), organic polymer (haze inhibitor), and the like can be used.

The volume of the slurry tank is the same as that of the conventional tank (volume 1) since the slurry supply method of the present invention is a system in which the slurry is replenished to the tank by the amount of slurry used.
(100 liters or more). For example, 20 liters.

[0010] The target value for the temperature control of the slurry is not limited. However, it is generally around 30 ° C. Normally, the temperature of the slurry is normal temperature, and the temperature is raised to the target value by the temperature control means. However, if the slurry is hot,
The temperature is cooled by the temperature adjusting means to obtain a target value. The type of the temperature adjusting means is not limited. For example, a heat exchanger that changes the temperature of the slurry by exchanging heat with a temperature control medium introduced from outside may be employed. Further, for example, a heating device such as an electric heater or a boiler may be employed. In addition, various cooling devices (air cooling type, water cooling type, etc.) may be adopted. The size of the temperature control means is not limited. However, since the present invention replenishes the slurry with the used amount of the slurry in the tank, it is possible to reduce the size more than the conventional temperature control means. As a detector of the amount of slurry supplied to the semiconductor wafer manufacturing apparatus, various flow sensors such as a vortex flow sensor, an ultrasonic flow sensor, and a silicon vibration flow sensor can be employed. There is no limitation on the method of replenishing the slurry tank with the same amount of slurry as the amount of slurry supplied to the semiconductor wafer manufacturing apparatus. For example, the opening degree of a valve connected to the slurry supply pipe may be adjusted manually by an operator. Further, the opening of an automatic valve connected to the slurry supply pipe may be adjusted by automatic control by a computer.

Further, in the invention according to claim 2, the difference between the amount of slurry supplied to the facility and the amount of slurry supplied to the slurry tank is 5% of the amount of slurry supplied.
The slurry supply method according to claim 1, wherein:
If the difference between the supply amount and the replenishment amount of the slurry exceeds 5%, it takes a long time to recover to the predetermined temperature.

According to a third aspect of the present invention, the slurry is circulated between a slurry tank for storing a slurry containing loose abrasive grains and temperature control means for controlling the temperature of the slurry discharged from the slurry tank. And a step of controlling the temperature of the slurry and a step of supplying the slurry after the temperature adjustment to the facility using the slurry. This is a slurry supply method for replenishing a slurry of a difference amount to the slurry tank at any time. When the slurry once supplied to the equipment to be used is collected and reused, the amount of consumption in the equipment is supplemented.

According to a fourth aspect of the present invention, there is provided a slurry tank for storing a slurry containing loose abrasive grains, a slurry supply pipe for supplying the slurry stored in the slurry tank to a facility using slurry, and a slurry supply pipe for the slurry supply pipe. In a slurry supply device comprising: a temperature control means for controlling the temperature of the supplied slurry; and a slurry return pipe that branches off from the middle of the slurry supply pipe and returns the slurry after the temperature is adjusted to the slurry tank. Flow rate detecting means for detecting the amount of temperature-adjusted slurry supplied from the slurry supply pipe to the slurry using facility, and slurry replenishing means for replenishing the slurry tank with a slurry having substantially the same amount as the detected amount as needed. And a slurry supply device comprising:

For the transfer of the slurry, for example, a slurry pump is used to pump the slurry from the upstream side to the downstream side of the slurry pipe. The slurry pump may be, for example, a type in which a rotating blade is rotated inside a valve box to continuously transfer slurry, or a type in which a piston is linearly moved in a cylinder to intermittently transfer slurry. Further, as a means for transferring the slurry other than the slurry pump, there is, for example, a slurry suction transfer device for sucking the slurry from the downstream side of the slurry pipe by a negative pressure. Each connection position of the temperature control means and the slurry return pipe in the length direction of the slurry supply pipe is not limited. However, the connection position of the slurry return pipe must be downstream of the temperature control means and upstream of the flow path switching valve (including the connection position of the flow path switching valve). The configuration of the slurry supply means is not limited. For example,
A tank that stores the prepared slurry, a pipe that supplies the slurry from the tank to the slurry tank, and a valve that is provided in the middle of the pipe and that controls the degree of opening of the flow path in the pipe may be provided. Good.

According to a fifth aspect of the present invention, the difference between the amount of the slurry supplied to the slurry using equipment and the amount of the slurry supplied to the slurry tank is 5% or less of the supplied amount of the slurry. Item 5. A slurry supply device according to item 4.

According to a sixth aspect of the present invention, there is provided a slurry tank for storing a slurry containing free abrasive grains, a slurry supply pipe for supplying the slurry stored in the slurry tank to a slurry using facility, A slurry supply device comprising: a temperature control means for controlling the temperature of the slurry supplied to the pipe; and a slurry return pipe branched off from the middle of the slurry supply pipe and returning the temperature-controlled slurry to the slurry tank. In, the flow rate detecting means for detecting the difference between the amount of slurry supplied from the slurry supply pipe to the slurry using equipment and the amount returned to the slurry tank,
The slurry supply device includes a slurry replenishing unit that replenishes a slurry tank with a slurry having substantially the same amount as the detected amount as needed. When the slurry once supplied to the equipment to be used is recovered and reused by the replenishing means, the consumption of the equipment is replenished.

[0017]

According to the present invention, the temperature of the slurry is adjusted while circulating the slurry between the slurry tank and the temperature adjusting means, and when the temperature of the slurry reaches the set temperature, the slurry is used as a facility for using the slurry. , For example, to a semiconductor wafer manufacturing apparatus. At that time, the amount of the temperature-adjusted slurry supplied to the facility is detected, and the detected amount is fed back to supply a slurry of approximately the same amount as the detected amount to the slurry tank as needed. This makes it possible to reduce the size of the slurry tank, the size of the temperature control means, and the heat capacity of the temperature control means, and to suppress the heat capacity required for controlling the temperature of the slurry. further,
Conventionally, the processing of the semiconductor wafer was interrupted when the slurry was replenished. However, the processing of the semiconductor wafer can be continued even during the slurry replenishment. Also,
The difference between the slurry supply amount and the return amount can be supplied. The slurry can be collected and reused.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a slurry supply device according to one embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a slurry supply device to a semiconductor wafer manufacturing facility. The slurry supply device 10 is a single-wafer type wafer polishing device (slurry using facility) 11 for polishing the surface of a silicon wafer W one by one. The slurry is continuously supplied to the vessel. First, the configuration of the single wafer polishing apparatus 11 will be briefly described. A polishing head 27 is arranged above the polishing platen 16. A polishing cloth 17 is spread on the upper surface of the polishing platen 16. On the other hand, a silicon wafer W is attached to the lower surface of the polishing head 27 via a carrier plate 28 by wax. During wafer polishing,
While the polishing agent is supplied to the polishing pad 17 from the nozzle 18, the rotating polishing head 27 is lowered at a predetermined speed, and the surface (lower surface) of the silicon wafer W attached to the carrier plate 28 is removed together with the polishing platen 16. The silicon wafer W is polished one by one by pressing against the polishing surface (upper surface) of the rotating polishing pad 17 at a predetermined speed.

Hereinafter, the structure of the slurry supply device 10 will be described in detail. The slurry supply device 10 includes a preparation tank 12 for preparing an abrasive, a circulation tank (slurry tank) 14 for storing the prepared abrasive through a preparation slurry supply pipe 13, and a middle of the preparation slurry supply pipe 13. And an electric opening control valve V1 for adjusting the opening of the flow path of the abrasive formed in the pipe, and two continuous slurry supply pipes 15A and 15B. Is provided between a slurry supply pipe 15A, 15B and a nozzle 18 for supplying the polishing agent to a polishing cloth 17 spread on the upper surface of a polishing platen 16 constituting a part of the wafer polishing apparatus 11, and a series of Solenoid valve (flow path switching valve) V2 for opening and closing the slurry flow path formed in the slurry, and the slurry supply pipe 1
A slurry pump 20 connected to the upstream end of the slurry supply pipe 5A for pumping the abrasive in the circulation tank 14 toward the wafer polishing apparatus 11; and a slurry pump 20 for the slurry supply pipe 15A.
A filter 21 that is connected to a portion downstream of the filter and removes foreign matter in the abrasive discharged from the circulation tank 14, and is connected to a portion downstream of the filter 21 of the slurry supply pipe 15A,
A heat exchanger 22 for raising the temperature of the abrasive after filtering foreign matter to a predetermined temperature (30 ° C.) by heat exchange with a predetermined heating medium, and a portion between the heat exchanger 22 of the slurry supply pipe 15A and the solenoid valve V2; One end is connected to the slurry return pipe 25 for returning the temperature-controlled abrasive to the circulation tank 14; A flow rate sensor 31 connected to the vicinity of the nozzle 18 of the slurry supply pipe 15B for detecting the flow rate of the abrasive supplied from the nozzle 18; a temperature sensor 23 for detecting the flow rate sensor 31 and the temperature of the abrasive in the circulation tank 14; And a control unit 26 that opens and closes each of the valves V1, V2, and V3 based on the detection signal from the controller.

In the mixing tank 12, an abrasive is produced.
Specifically, 50-200 liters of RO
Add DEL2398 (trade name) and dilute about 10-fold. The mixing tank 12 and the mixing slurry supply pipe 13
The opening control valve V1 constitutes a slurry supply means. The circulation tank 14 uses a container having a volume of 20 to 100 liters. In addition to the temperature sensor 23, a concentration meter 24 for detecting the concentration of the abrasive is attached to the circulation tank 14.

Next, the operation of the slurry supply apparatus 10 according to this embodiment will be described. As shown in FIG. 1, first, an abrasive containing free abrasive grains is prepared in the preparation tank 12. The abrasive thus obtained is once stored in the circulation tank 14 through the prepared slurry supply pipe 13 by opening the opening degree control valve V1. At this time, the solenoid valve V2 is closed and the solenoid valve V3 is open. Slurry pump 20
Is operated, the abrasive is pumped from the bottom of the circulation tank 14 to the slurry supply pipe 15A. Thereafter, foreign matter in the abrasive is removed by the filter 21 and the temperature is increased by the heat exchanger 22. The heated abrasive is returned from the slurry return pipe 25 to the circulation tank 14 because the electromagnetic valve V2 is closed and the electromagnetic valve V3 is opened. Thus, the circulation tank 14, the slurry supply pipe 15, and the slurry return pipe 2
5, a closed abrasive circulation loop is formed. The abrasive is gradually heated to 30 ° C. while being circulated in the circulation loop. Confirmation of the temperature of this abrasive
This is performed by detecting the liquid temperature of the abrasive in the circulation tank 14 with the temperature sensor 23. This detection signal is transmitted to the control unit 2
Sent to 6.

When the temperature of the abrasive reaches 30 ° C., the control unit 26
Sends a valve opening command to the solenoid valve V2 to open the solenoid valve V2. On the other hand, the controller 26 issues a valve closing command to the solenoid valve V3 to close the solenoid valve V3. Thereby, the abrasive flows into the slurry supply pipe 15B, and the abrasive is supplied from the nozzle 18 to the upper surface of the polishing cloth 17 at a rate of 1 liter / minute.
The amount of the abrasive supplied to the polishing pad 17 is detected by the flow sensor 31, and the detection signal is sent to the control unit 26.
In the control unit 26, based on the detection signal, the opening degree control valve V
A command to adjust the opening is issued to 1. As a result, the opening control valve V
1 is adjusted, and the flow rate of the abrasive supplied from the preparation tank 12 to the circulation tank 14 via the preparation slurry supply pipe 13 is adjusted to the amount of the abrasive supplied from the nozzle 18 to the polishing cloth 17. It is controlled at the same 1 liter / minute. In addition,
This control is based on the difference between the amount of the abrasive supplied to the wafer polishing apparatus 11 and the amount of the abrasive supplied from the mixing tank 12 to the circulation tank 14. If it is 5% or less, it is regarded as an allowable range. In the wafer polishing apparatus 11, the polishing cloth 17 rotates integrally with the polishing platen 16, and the rotating polishing head 27 is pressed against the polishing surface (upper surface) of the polishing cloth 17 at a predetermined pressure.
Thus, the surface of the silicon wafer W is polished at a predetermined polishing rate.

As described above, the amount of the temperature-controlled polishing agent supplied to the wafer polishing apparatus 11 is detected, and the detected amount is fed back so that the polishing agent is supplied to the circulation tank 14 as needed in accordance with the usage of the polishing agent. Therefore, the total amount of the abrasive circulated in the circulation loop can be reduced as compared with the conventional amount. As a result, the volume of the conventional circulation tank was 100 liters, but can be reduced to 50 liters. In addition, since the amount of circulation of the abrasive is small, the heat exchanger 22 can be downsized and the heat capacity of the heat exchanger 22 can be reduced, while the heat capacity required for controlling the temperature of the abrasive can be suppressed. it can.
In addition, in the conventional slurry supply device, the polishing agent was replenished to the circulation tank after the polishing agent in the circulation tank was used up. Therefore, the polishing of the silicon wafer was interrupted when the polishing agent was replenished. The wafer can be polished also at the time of replenishment.

FIG. 2 shows another embodiment of the present invention. In this embodiment, the slurry used in the polishing apparatus 11 is collected and reused. That is, the recovered slurry is supplied from the cascade type slurry recovery tank 41 to the slurry tank 14. In the slurry tank 14, the temperature is adjusted via the heat exchanger 22 and the circulation system. The temperature-controlled slurry is supplied from the nozzle 18 to the polishing machine 11. Reference numeral 42 denotes a new liquid supply tank for replenishing the recovery tank 41 with the new slurry liquid in an amount consumed by the polishing machine 11. 43,4
Reference numerals 4 and 45 denote ultrasonic flow meters, and these detection signals are input to the control unit 26. The control unit controls opening and closing of valves 46, 47, 48, and 49 interposed in the slurry pipe. Other configurations are the same as those of the above embodiment. According to this embodiment, once used slurry can be reused. In that case, adjustment to a predetermined temperature is also performed. In addition, the shortage due to consumption is replenished at any time.

[0025]

According to the present invention, after the temperature is adjusted, the slurry having the same amount as the amount of the slurry supplied to the semiconductor wafer manufacturing apparatus is replenished to the slurry tank as needed.
The size of the slurry tank, the size of the temperature control means, and the heat capacity of the temperature control means can be reduced, and the heat capacity required for temperature control of the slurry can be suppressed. Further, the processing of the semiconductor wafer can be continued even when the slurry is supplied to the slurry tank. Further, the slurry can be reused in this supply method.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a slurry supply device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a slurry supply device according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 slurry supply device, 11 wafer polishing device (slurry use equipment), 12 preparation tank (slurry supply means), 13 preparation slurry supply pipe (slurry supply means), 14 circulation tank (slurry tank), 15A, 15B slurry supply pipe, 22 heat exchanger (temperature control means), 25 slurry return pipe, 31 flow rate sensor (flow rate detection means), 43, 44, 45 ultrasonic flow meter (flow rate detection means) V1 opening control valve (slurry replenishment means), V2 Solenoid valve (flow path switching valve).

Continued on the front page (72) Inventor Tadashi Denda 1-5-1, Otemachi, Chiyoda-ku, Tokyo Mitsubishi Materials Silicon Co., Ltd. (72) Inventor Yoshiki Kobayashi 508-2 Nakagami, Iruma City, Saitama Prefecture Xevi Co., Ltd. F term in male (reference) 3C047 FF08 GG15 GG19 3C058 AA07 AC01 AC02 AC04 BA02 BA08 BB09 CB03 CB05 CB10 DA02 DA17

Claims (6)

[Claims] 1. A method for controlling the temperature of a slurry while circulating the slurry between a slurry tank for storing a slurry containing free abrasive grains and a temperature controlling means for controlling the temperature of the slurry discharged from the slurry tank. Performing the step of supplying the slurry after the temperature control to the facility using the slurry, wherein the amount of the temperature-controlled slurry supplied to the facility using the slurry is detected, A slurry supply method for replenishing the slurry tank with the same amount of slurry as the detected amount at any time. 2. The amount of slurry supplied to the facility,
2. The slurry supply method according to claim 1, wherein a difference between the slurry supply amount and the slurry supply amount is 5% or less of the slurry supply amount. 3. 3. The temperature of the slurry is adjusted while circulating the slurry between a slurry tank for storing a slurry containing free abrasive grains and a temperature adjusting means for adjusting the temperature of the slurry discharged from the slurry tank. And supplying the slurry after temperature control to the slurry-using facility, wherein the slurry having a difference between the amount of the slurry supplied to the slurry-using facility and the amount returned to the slurry tank is reduced. And a slurry supply method for replenishing the slurry tank as needed. 4. A slurry tank for storing a slurry containing free abrasive grains, a slurry supply pipe for supplying the slurry stored in the slurry tank to a slurry using facility, and a slurry supply pipe for supplying the slurry to the slurry supply pipe. In a slurry supply device, comprising: a temperature adjusting means for adjusting a temperature; and a slurry return pipe branched from the middle of the slurry supply pipe and returning the slurry whose temperature has been adjusted to the slurry tank. Slurry comprising flow rate detecting means for detecting the amount of temperature-adjusted slurry supplied to the slurry using facility, and slurry replenishing means for replenishing the slurry tank with a slurry of substantially the same amount as the detected amount as needed. Feeding device. 5. The slurry according to claim 4, wherein a difference between an amount of the slurry supplied to the slurry using facility and an amount of the slurry supplied to the slurry tank is 5% or less of the supplied amount of the slurry. Slurry supply device. 6. A slurry tank for storing a slurry containing free abrasive grains, a slurry supply pipe for supplying the slurry stored in the slurry tank to a slurry using facility, and a slurry supply pipe for supplying the slurry to the slurry supply pipe. In a slurry supply device, comprising: a temperature adjusting means for adjusting a temperature; and a slurry return pipe branched from the middle of the slurry supply pipe and returning the slurry whose temperature has been adjusted to the slurry tank. Flow rate detecting means for detecting a difference between the amount of slurry supplied to the slurry using equipment and the return amount to the slurry tank; and a slurry replenishing means for replenishing the slurry tank with an amount of slurry substantially equal to the detected amount as needed. Slurry supply equipment.