JP2005052952A - Slurry feeder and the slurry feeding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem: a conventional slurry feeder takes in dry ambient air into a tank when the level of slurry is lowered, and therefore if feeding of the slurry to a chemical mechanical polishing machine is stopped over a predetermined period of time, drying or coagulation of the slurry occurs on a tank inner wall over an area between a fluid level at which slurry refill is stopped and a currently stopped fluid level. <P>SOLUTION: A new slurry feeder is provided with a fluid level sensor 2 or a load cell 4 for controlling a remaining quantity of the slurry in the slurry tank 1, which automatically refills the slurry or stops refill of the slurry. Therefore the slurry is refilled before the slurry adhering to the tank inner wall dries by using a timer, according to a slurry automatic refilling sequence. Further, in order to moisten the interior of the tank, mist is sprayed in the tank by a spray nozzle 3 at an arbitrarily set time intervals, or the interior of the tank is humidified by a humidifier. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a slurry supply apparatus and a slurry supply method for supplying a slurry for polishing a semiconductor substrate.

In the conventional slurry supply apparatus, the remaining amount of slurry in the tank in the slurry supply apparatus is managed by detecting the liquid level of the liquid level sensor, and replenishment of the slurry and stop of replenishment are performed based on the detection result (for example, patent document) 1). In the case of the slurry replenishment sequence based on the liquid level detection result by the liquid level sensor, the supply to the chemical mechanical polishing apparatus is stopped for a certain time (for example, 15 minutes) before the liquid level reaches the liquid level sensor for slurry replenishment. When the slurry is replenished, the slurry is dried and agglomerated on the inner wall of the tank between the liquid level stop position when the slurry is replenished and the current liquid level stop position.
JP 2000-61820 A

  In the conventional slurry supply apparatus, the casing of the slurry supply apparatus is exhausted to prevent the slurry atmosphere from diffusing into the clean room. Since the volume of the exhausted air takes in dry air (about 40%) in the clean room, the atmosphere in the casing of the slurry supply device is always dry.

  When the liquid level of the slurry is lowered, the outside air of the tank (atmosphere inside the case of the slurry supply device) is taken into the tank, and in the case of the slurry replenishment sequence by the liquid level sensor, the liquid level up to the liquid level sensor for slurry replenishment When the supply to the chemical mechanical polishing apparatus is stopped for a certain period of time (for example, 15 minutes) before the time reaches, the tank inner wall between the liquid level at which slurry replenishment is stopped and the current liquid level is stopped. It was found that drying and aggregation occurred.

  When the slurry is replenished after being stopped for a certain time or longer, the dried and agglomerated slurry is mixed with the replenished slurry on the inner wall of the tank, so that scratches are generated on the surface of the polished wafer in chemical mechanical polishing.

  Accordingly, an object of the present invention is to provide a supply apparatus and method in which slurry does not dry, aggregate, precipitate, or change in solid content concentration in a tank.

  In order to achieve the above object, a slurry supply apparatus of the present invention includes a sealed tank for storing slurry, a liquid level sensor for starting slurry replenishment for managing the remaining amount of slurry in the tank, and replenishment. And a stop liquid level sensor.

  Further, the slurry supply apparatus of the present invention includes a sealed tank for storing slurry, and a load cell for supporting the tank and managing the remaining amount of the slurry in the tank. To do.

  Moreover, the slurry supply apparatus of the present invention further includes a spray nozzle for injecting a mist-like liquid into the tank, or a humidifier for wetting the inside of the tank is connected to the tank.

  In the slurry supply method of the present invention, when the slurry replenishment start liquid level sensor provided in the sealed tank for storing the slurry is below the position of the slurry replenishment start liquid level sensor in the tank Replenishing the slurry in the tank, and stopping the replenishment of the slurry when the replenished slurry reaches the position of a replenishment stop liquid level sensor.

  The slurry supply method of the present invention also supports a sealed tank for storing slurry, and manages the weight of the tank containing the slurry by a load cell for managing the remaining amount of the slurry in the tank. When the load cell recognizes the weight of the slurry replenishment start, the tank is replenished with the slurry, and when the weight of the slurry replenishment stop is recognized, the slurry replenishment is stopped.

  The slurry supply method of the present invention further includes a step of spraying a mist-like liquid from the spray nozzle into the tank to increase the humidity in the tank and preventing the slurry from drying on the inner wall of the tank. Yes.

  As described above, the slurry replenishment start liquid level sensor and the replenishment stop liquid level sensor, or the load cell manages the replenishment and replenishment of the slurry in the tank, and the mist liquid is injected into the tank. By increasing the humidity in the tank, it is possible to prevent the slurry from drying, agglomerating, precipitating, and changing the solid content concentration in the tank, ensuring a uniform particle size and uniform solid content concentration and enabling uniform polishing. become.

  FIG. 1 is a schematic configuration diagram showing an embodiment of a slurry supply apparatus of the present invention. In FIG. 1, 1 is a sealed slurry tank for storing slurry, 2 is a liquid level sensor for detecting the liquid level of the slurry in the slurry tank 1 and managing the remaining amount of the slurry, 3 is in the slurry tank 1 The spray nozzle 4 for wetting is also a load cell for managing the remaining amount of slurry. Here, the liquid level sensor 2 includes a slurry replenishment sensor 2a and a slurry replenishment stop sensor 2b. The remaining amount of slurry may be managed by at least one of the liquid level sensor 2 or the load cell 4, and only at least one of the components may be provided. 5 is an exhaust pipe for exhausting from the casing 20 of the slurry supply apparatus, 6 is a pipe for supplying the slurry to the slurry tank 1 from the primary side, 7 is a pipe for supplying the slurry from the slurry tank 1 to the chemical mechanical polishing apparatus, Reference numeral 8 denotes a pipe connected to the slurry tank 1 for supplying pure water or a chemical liquid when the inside of the slurry tank 1 is washed. Reference numeral 9 denotes a pipe for discharging slurry or other waste liquid in the slurry tank 1. Further, 10 is a slurry tank 1, a slurry circulation pipe for circulating the slurry, 12 is a humidifier that sends moisture when the liquid level changes in the slurry tank 1, and 11 is moisture between the slurry tank 1 and the humidifier 12. It is a flow path. A pipe 13 is connected to the spray nozzle 3 and supplies pure water or a chemical solution for wetting the slurry tank 1. As a configuration for wetting the slurry tank 1, only the spray nozzle 3 or the humidifier 12 need be provided.

  FIG. 2 is a schematic configuration diagram showing another embodiment of the slurry supply apparatus of the present invention. In FIG. 2, the slurry supply apparatus shown in FIG. 1 is different from the slurry supply apparatus shown in FIG. 1 in that the moisture flow path 11 between the slurry tank 1 and the humidifier 12 is further filled with moisture and dry air when the liquid level changes. This is the point that a pipe 14 that does not change is provided.

  Next, a slurry supply method using the slurry supply device, particularly a slurry replenishment method will be described below.

  The slurry for polishing the silicon substrate is composed of silica powder and a strong alkali dispersant such as ammonia. The primary particles of silica are about 20 to 30 nm, and these are collected to form a secondary of about 0.2 μm. Consists of particles.

  The slurry supply device includes a liquid level sensor 2 or a load cell 4 in order to manage the remaining amount of slurry in the slurry tank 1. When the position of the slurry in the slurry tank 1 falls below the slurry replenishment sensor 2a which is a liquid level sensor for starting slurry replenishment, it is recognized as the slurry replenishment position, or the weight of the slurry tank 1 is reduced by the load cell 4 When the replenishment weight is reached, the slurry is supplied from the primary side through the pipe 6, and the position of the slurry reaches the slurry replenishment stop sensor 2 b that is a replenishment stop liquid level sensor, or the weight of the slurry tank 1 is slurried by the load cell 4. When the replenishment stop weight is reached, the slurry supply from the primary side pipe 6 stops. As described above, the slurry replenishment sensor 2a and the slurry replenishment stop sensor 2b, or the load cell 4 manages the remaining amount of the slurry, thereby providing slurry replenishment automatic control means for automatically replenishing or replenishing the slurry.

  However, in the case of this slurry supply method, if the time until the slurry is automatically replenished becomes longer, specifically, if the polishing apparatus stops for a certain time (for example, 15 minutes) during the slurry supply, the slurry replenishment There is a problem that the slurry dries and aggregates on the inner wall of the tank between the stop sensor 2b and the current stop liquid level. As an improvement measure, the slurry supply method of the present invention is such that the slurry liquid level is lowered from the slurry replenishment stop sensor 2b and the slurry is supplied from the primary side through the pipe 6 after a predetermined time (time until the slurry dries and aggregates). The slurry is replenished and filled before the slurry on the inner wall of the slurry tank 1 dries and aggregates to prevent drying. For example, a timer device such as a timer may be used for the management of supplying the slurry so that the liquid level drops from the slurry replenishment stop sensor 2b and the liquid level is restored after a predetermined time. In terms of time, for example, it is set to 10 minutes.

  Next, a method for maintaining wetness and humidity in the slurry tank 1 of the slurry supply apparatus will be described below.

  In addition to preventing slurry drying in the above-described slurry replenishing method, as a further drying prevention measure, as a method of moistening the inside of the slurry tank 1 and maintaining the humidity, spraying a mist liquid from the spray nozzle 3 into the slurry tank 1 Alternatively, the slurry tank 1 is humidified from the humidifier 12 through the moisture channel 11.

  Further, the pipe 14 is used as a control means for preventing the exchange of the dry atmosphere introduced with the lowering of the liquid level of the slurry in the tank and the wet atmosphere, controlling the wetness in the tank, and maintaining the humidity. I have. By flowing the air that moves (in and out) due to the fluctuation of the liquid level of the slurry to the humidifier 12, it is possible to prevent the replacement with the dry outside air and to maintain the humidity of the slurry tank 1. Alternatively, a pipe 14 having a volume of gas that moves (in / out) as the liquid level of the slurry moves is connected to the slurry tank 1 in the housing 20 so that the moisture in the slurry tank 1 and the dried outside air are switched. The humidity in the slurry tank 1 can be maintained.

The schematic block diagram which shows one Embodiment of the slurry supply apparatus of this invention The schematic block diagram which shows other one Embodiment of the slurry supply apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Slurry tank 2 Liquid level sensor 3 Spray nozzle 4 Load cell 5 Exhaust piping 6, 7, 8, 9, 13 Piping 10 Slurry circulation piping 11 Humidity channel 12 Humidifier 14 Piping

Claims (14)

A slurry supply apparatus for supplying a slurry as an abrasive for chemical mechanical polishing, wherein a sealed tank for storing the slurry and a remaining amount of the slurry in the tank are managed. A slurry supply device comprising a slurry replenishment start liquid level sensor and a replenishment stop liquid level sensor. A slurry supply apparatus for supplying a slurry, which is an abrasive, for chemical mechanical polishing, comprising: a sealed tank for storing the slurry; and supporting the tank, and the remaining slurry in the tank. A slurry supply apparatus comprising a load cell for managing the amount. The slurry supply apparatus according to claim 1 or 2, further comprising a spray nozzle for injecting a mist-like liquid into the tank. The slurry supply apparatus according to claim 1, wherein a humidifier for moistening the inside of the tank is connected to the tank. 2. A control means for controlling the wetting in the tank by preventing the exchange of the dry atmosphere introduced with the lowering of the liquid level of the slurry in the tank and the moist atmosphere. 2. The slurry supply apparatus according to 2. 2. The slurry supply apparatus according to claim 1, further comprising a slurry replenishment automatic control unit that automatically replenishes or stops replenishment of slurry by management of a slurry replenishment start liquid level sensor and a replenishment stop liquid level sensor. 3. The slurry supply apparatus according to claim 2, further comprising a slurry replenishing automatic control means for automatically replenishing or stopping the replenishment of the slurry by managing the remaining amount of slurry in the tank by measuring the load cell. After the replenishment stop liquid level sensor by the slurry replenishment automatic control means, after the slurry replenishment stop, the slurry is replenished when a certain time elapses and the slurry is replenished, and a timed device is provided to prevent drying of the inner wall of the tank. The slurry supply apparatus according to claim 6 or 7. A liquid level sensor for starting slurry replenishment provided in a sealed tank for storing slurry of a slurry supply apparatus for supplying slurry as a polishing agent for chemical mechanical polishing is provided with the slurry in the tank. Replenishing the slurry in the tank when it is below the position of the slurry replenishment liquid level sensor, and stopping replenishment of the slurry when the replenished slurry reaches the replenishment stop liquid level sensor. A slurry supply method comprising: A slurry supply device for supplying slurry as a polishing agent for chemical mechanical polishing supports a sealed tank for storing slurry, and a load cell for managing the remaining amount of the slurry in the tank. , Managing the weight of the tank containing the slurry, replenishing the slurry into the tank when the load cell recognizes the weight of slurry replenishment start, and stopping replenishment of the slurry when recognizing the weight of slurry replenishment stop And a slurry supplying method. 10. A step of spraying a mist-like liquid from the spray nozzle into the tank to increase the humidity in the tank and preventing the slurry from drying on the inner wall of the tank. The slurry supply method according to 10. Spray of mist from the spray nozzle is performed every arbitrarily set period, and after spraying the slurry in the tank, spray, and then replenishing and replenishing the slurry in the tank to prevent mist from entering the slurry The slurry supply method according to claim 11. 11. The slurry according to claim 9, further comprising a step of increasing the humidity in the tank using a humidifier connected to the tank and preventing drying of the slurry on the inner wall of the tank. Supply method. 11. The method according to claim 9, further comprising a step of replenishing the slurry halfway after a predetermined time, even if the slurry is reduced and the slurry is not replenished after the slurry replenishment is stopped. Slurry supply method.

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