JP2005313266A - Slurry feeding device, and feeding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for feeding optimum slurry to a CMP without promoting generation of giant particles even when slurry used in the CMP has coagulating and sedimenting tendency. <P>SOLUTION: This device comprises a flow control part to make fluids to be mixed a prescribed flow, and a mixing part to send the fluids of the prescribed flow respectively to a single flow passage to be mixed. Since they are thus mixed to be directly sent to a CMP polishing part, generation of a large amount of giant particles can be avoided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a slurry supply apparatus and supply method used for CMP in the semiconductor field, and more particularly to a CMP slurry supply apparatus and supply method suitable for feeding a slurry having high sedimentation properties such as ceria and alumina. .

  In the conventional CMP slurry supply method and apparatus, in the case of a highly sedimentable slurry, a method in which the slurry is supplied in a stock solution tank of about 10 to 20 liters and individually stirred immediately before being transferred to the solution supply tank is used. It was done.

  Moreover, the conventional method and the apparatus were equipped with the supply tank which mixes a slurry undiluted solution, an additive chemical | medical solution, and a pure water, and the method of mixing and supplying a slurry and an additive previously was employ | adopted. And, from the supply tank, a so-called general circulation-CMP inner roller tube comprising a circulation pipe for returning the discharged slurry to the supply tank again, and a pipe branched from the circulation pipe to supply the slurry to the CMP. The pump extraction table supply method was adopted.

  However, in a stock solution tank of about 10 to 20 liters, the stock solution tank must be replaced frequently, so there is a possibility that production may be hindered in a mass production factory. There was a problem that could not be used because it would occur.

  In addition, the supply tank, which is the transfer destination from the stock solution tank, always stores and agitates the slurry. As a result, the slurry agglomerates and dries due to scattering on the inner wall and lid of the tank, and the abrasive particles that have become giant particles reach the CMP section. Since the liquid was fed, there was a problem of damaging the wafer.

  In addition, depending on the type of slurry, if the chemical tank as an additive is mixed in advance depending on the type of slurry, aggregation may be promoted by chemical action, which may damage the wafer. There was also a problem to give.

  Further, in the roller tube method in which the tube is extracted while squeezing, dust is generated as the tube itself is used, which causes a problem of damaging the wafer.

  In order to avoid such damage to the wafer, a method is provided in which filters are provided at a plurality of locations in the piping to remove the abrasive particles that have become giant particles, but large quantities of particles are generated. Since the filter had to be changed frequently, there was a problem that the work efficiency was not improved and the cost was increased.

  Moreover, two supply tanks must be installed because it is necessary to switch to the other supply tank before the CMP slurry in one supply tank runs out, and piping for circulating aggregated CMP slurry is required. Therefore, there is a problem that the apparatus becomes large.

  The present invention is intended to solve such conventional problems at once, and even if the slurry used for CMP is cohesive and sedimentary, the generation of large particles is not promoted. It is an object of the present invention to provide a method and apparatus capable of always supplying an optimum slurry for CMP.

  The configuration of the present invention that meets the above-described object has a flow rate control unit that sets a fluid to be mixed to a predetermined flow rate, and a mixing unit that mixes fluids having a predetermined flow rate by flowing them in the same flow path. And The apparatus of the present invention is mainly used for supplying CMP slurry, but can also be applied to in-line mixing of two or more fluids such as water and hydrofluoric acid.

  The CMP slurry supply apparatus of the present invention has a flow rate control unit having a predetermined flow rate, and a mixing unit that mixes fluids having a predetermined flow rate by flowing them in the same flow path. It is provided immediately before the processing section (claim 2). The term “immediately before the CMP processing portion” means a distance at which agglomeration that damages the wafer does not occur before the CMP slurry and the additive are mixed and transferred to the CMP processing portion.

  The flow rate control unit includes a pressure reducing valve that suppresses pump pulsation, a flow meter, a flow rate adjustment pinch type valve, and an electric control that processes a signal from the flow meter and controls the pinch type valve. Preferred (claim 3). With this configuration, it is possible to control and supply the optimum slurry for CMP without using a roller tube pump, which has been one of the causes of damage to the wafer.

  It is preferable to mix the CMP slurry, the additive chemical solution, and pure water by flowing them in the same flow path immediately before the CMP processing section.

  By configuring in this way, it is possible to completely suppress the generation of agglomerated and dried abrasive grains that have occurred in conventional supply tanks, and it is not necessary to circulate CMP slurry. It can also be miniaturized.

  It is preferable to provide a drum having a pipe for separately circulating the CMP slurry and the additive chemical solution immediately before the flow rate control unit, and a stirring mechanism for separately storing the CMP slurry and the additive chemical solution, respectively. 5). By configuring in this way, it is possible to use a 200 liter slurry drum that is the optimal drum capacity for a mass production factory, reducing the number of frequently performed drum replacement operations from 1/5 to 1/10 times, and By stirring the inside of the drum with a high-speed stirring blade, it becomes possible to maintain the state of the slurry in an optimum state for CMP.

  In the CMP slurry supply method of the present invention, the CMP slurry and the additive chemical solution are mixed by flowing the flow rate through the same flow path with the flow rate control unit controlled at a predetermined mixing ratio, and then the CMP process. It supplies to a part.

  In short, the present invention supplies the optimum slurry for CMP, because even when the additive is mixed in advance, even if the slurry is agglomerated by the action of the additive, it is mixed with the additive immediately before the CMP processing section. The gist is that it has become possible.

  According to the present invention, even if the slurry used in CMP is coagulable and sedimentary and is supplied by a large-capacity drum, it is mixed with the additive immediately before the CMP treatment section, so that aggregation and sedimentation occur. Since it is not promoted, it is possible to supply the optimum slurry for CMP without affecting the productivity of the mass production plant.

  Next, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a piping configuration diagram showing an example of a CMP slurry supply apparatus according to the present invention.

  As shown in FIG. 1, this apparatus includes drums 1 and 2 containing a slurry stock solution or a chemical solution, a stirrer 4 for stirring the slurry, and a pump 3 for circulating and feeding the slurry and the chemical solution additive. . One of the drums 1 and 2 contains a slurry stock solution and the other contains a chemical solution. The chemical solution storage drum does not require the stirrer 4 in particular, but in this way, the slurry stock solution can be stored in any tank. The slurry stock solution or the chemical solution is circulated between the drums 1 and 2 immediately before the valves 6 and 6 to the flow rate control unit 8.

  Pure water 11 supplied from the factory is introduced from a pure water introduction valve 5 and used for cleaning the slurry valve 6 and the flow rate control unit 8. In addition, by using the pure water introduction valve 5 and the slurry valve 6 as an integral valve manifold 21, it is possible to supply the optimum slurry for CMP without liquid accumulation. In general, one of the slurry valves 6 and 6 is used for the slurry and the other is used for the chemical solution (additive), but both can be used for the slurry.

  The flow controller 8 includes a pressure reducing valve 101 that suppresses pump pulsation, a flow meter 102, a flow adjustment pinch valve 103, and an electric control 104 that processes a signal from the flow meter 102 and controls the pinch valve 103. Yes.

  The slurry stock solution and the chemical solution that have passed through the separate flow rate control units 8 merge at the mixing unit 9, pass through the same pipe, are sent to the CMP polishing unit 10, and are used for polishing the processing target wafer 51. In this same pipe, the pure water introduction valve 5 is mixed with the pure water 11 for dilution passing through the pressure reducing valve 101, the flow meter 102 and the valve 7.

  In addition, the slurry stock solution and the chemical drums 1 and 2 can be supplied without interruption by using a two-stand switching type.

  FIG. 2 is a piping configuration diagram showing another embodiment of the CMP slurry supply apparatus of the present invention. The names overlapping with those in FIG.

  As shown in FIG. 2, in this embodiment, the slurry supply solution or chemical solution supply receptacles 15 and 16 and the pure water acceptance 11a, the slurry or chemical solution dilution pure water introduction valve 7a, the flow rate control unit 8a, and the wafer processing unit are used. 12, the example which equipped the chemical | medical solution concentration meter 13 and the process target wafer 51a is shown. In the apparatus of this embodiment, instead of CMP slurry, the flow rate of an inorganic chemical solution such as hydrogen peroxide solution or hydrofluoric acid can be suitably used for supply to the processing unit. It can be confirmed by the chemical concentration meter 13 that the slurry or the chemical is at a predetermined concentration.

  FIG. 3 is a piping configuration diagram showing another embodiment of the CMP slurry supply apparatus according to the present invention. The names that overlap with those in FIGS. 1 and 2 are denoted by the symbol b.

  As shown in FIG. 3, in this embodiment, the slurry supply solution or chemical solution feed receivers 15 b and 16 b and the pure water receiver 11 b, the slurry or chemical solution dilution pure water introduction valve 7 b, the flow rate controller 8 b, and CMP polishing are used. It comprises a wafer processing unit 12b such as a cleaning unit or a component concentration meter 13b, a processing target wafer 51b, a liquid storage tank 17 after preparation, a stirrer 4b, a circulation and liquid feeding pump 18, and a circulation and liquid feeding switching valve 19. An example is shown. In the present embodiment, by installing the liquid storage tank 17 immediately before the processing unit and measuring the concentration by monitoring, the CMP slurry having a more stable concentration can be sent to the CMP processing unit and the cleaning unit.

  FIG. 4 shows the responsiveness and flow stability of the flow control unit of the present invention. The horizontal axis c represents the passage of time and the unit is seconds. The vertical axis d represents the flow rate, and the unit is 1 cubic centimeter per minute. The measurement starts at 100 cubic centimeters per minute at time 0 seconds, stops after 60 seconds, starts after 30 seconds, and stops after 60 seconds three times for each flow rate. f) The flow was set at a flow rate of 300 cubic centimeters (e), and the actual flow rate was measured and displayed on the graph. After starting, the target flow rate was reached after 8 seconds although it was slightly different for each flow rate. As is apparent from FIG. 4, in the present invention, control is possible within a range of ± 0.2 to 2.0% with respect to the target density.

  Since the present invention is useful as a slurry supply device for a semiconductor CMP process, particularly as a slurry supply device for sending ceria slurry having high sedimentation and cohesion properties to a polishing device, the present invention has high applicability.

  In addition to the ceria slurry, since the equipment size can be reduced compared to the supply equipment that has been used so far using the weighing tank and the mixing tank, and the equipment is less burdened on the environment because there is no need for tank cleaning. Other slurries have high industrial applicability.

  Furthermore, it is applicable not only to slurry but also to in-line mixing of two or more kinds of chemicals, the apparatus size can be reduced, and since there is no need for tank cleaning, industrial applicability is high.

It is a piping block diagram which shows one Example of this invention. It is a piping block diagram which shows the other Example of this invention. It is a piping block diagram which shows the other Example of this invention. It is the graph which measured the responsiveness and flow stability of the flow control part of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Slurry or chemical | medical solution drum 2 Slurry or chemical | medical solution drum 3 Slurry or chemical | medical solution delivery pump 4, 4b stirrer 5 Pure water introduction valve 6 Slurry valve 7, 7a, 7b Pure water introduction valve 8, 8a, 8b Flow control part 9 In-line mixing Unit 10 CMP polishing unit 11, 11a, 11b Factory supplied pure water 12, 12b CMP processing unit or cleaning unit 13, 13b Component concentration meter 15, 15b Slurry or factory supplied chemical solution 16, 16b Slurry or factory supplied chemical solution 17 Storage Liquid tank 18 Circulation, liquid feed pump 19 Circulation, liquid feed switching valve 51, 51a, 51b Wafer 101 Pressure reducing valve 102 Flow meter 103 Flow rate adjusting pinch type valve 104 Electric control c Time elapse (second)
d Flow rate (1 &#13220; / min)
e 300 cubic centimeters per minute f 200 cubic centimeters per minute g 100 cubic centimeters per minute

Claims (6)

A flow control unit having a predetermined flow rate of the fluid to be mixed, and a mixing unit that mixes the fluids having the predetermined flow rate by merging the fluids and flowing them in the same flow path. Inline feeder. A flow rate control unit that sets a fluid to be mixed to a predetermined flow rate; and a mixing unit that mixes the fluids having a predetermined flow rate by joining them together and flowing them in the same flow path. An apparatus for supplying CMP slurry, comprising: The flow rate control unit includes a pressure reducing valve that suppresses pump pulsation, a flow meter, a flow rate adjustment pinch type valve, and an electric control that processes a signal from the flow meter and controls the pinch type valve. Item 3. The apparatus according to Item 2. The apparatus according to claim 2 or 3, wherein the CMP slurry, additive chemical solution and pure water are mixed by flowing in the same flow path immediately before the CMP processing section. The pipe of circulating separately CMP slurry and additive chemical | medical solution immediately before the said flow control part, The drum which has a stirring mechanism which each accommodates this CMP slurry and additive chemical | medical solution respectively is provided. The device according to any one of the above. The CMP slurry flowing in the pipe and the additive chemical are controlled by the flow rate control unit so that a predetermined mixing ratio is obtained, and then mixed by flowing in the same flow path to be supplied to the CMP processing unit. A CMP slurry supply method characterized by the above.

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