JP2017143141A - Single-wafer cleaning apparatus and wafer cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single-wafer cleaning apparatus capable of suppressing defects on a wafer surface due to chemical liquid mist or the like generated by influence of turbulence when a wafer is cleaned using the single-wafer cleaning apparatus.SOLUTION: A single-wafer cleaning apparatus includes: a cup unit arranged in a chamber; a table section arranged in the cup unit, and holding and rotating a wafer; and a nozzle section for supplying chemical liquid to the wafer. The single-wafer cleaning apparatus further includes: an air supply section provided in the chamber; an air supply volume variable mechanism for adjusting an air flow of the air supply section; an exhaust section provided in the chamber; an exhaust air volume variable mechanism for adjusting an air flow of the exhaust section; and an anemometer for measuring air flow velocity at a position of a wafer edge held by the table section.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a single wafer cleaning apparatus and a wafer cleaning method.

  As a device for cleaning a wafer such as a semiconductor wafer, a batch type cleaning processing device for cleaning by immersing a plurality of wafers in a chemical bath filled with a chemical solution, and rotating one wafer with respect to the wafer. In addition, there is a single-wafer type cleaning apparatus that injects a chemical solution for cleaning. In recent years, with the miniaturization of semiconductor devices and the increase in size of wafers, single wafer cleaning apparatuses having a high cleaning effect tend to be used (Patent Document 1).

  As a single wafer type cleaning processing apparatus, a cleaning processing device casing called a chamber, an air supply part provided at the upper part of the chamber for supplying air, an exhaust part provided at the lower part of the chamber for exhausting air, and a wafer 2. Description of the Related Art A single-wafer cleaning apparatus is known that includes a table unit that holds and rotates, a nozzle unit that supplies a chemical solution onto a wafer, and a cup unit that collects or drains the scattered chemical solution.

  In such a conventional single wafer cleaning processing apparatus, the air speed and the air volume of the air supply section and the exhaust section are measured (monitored), and the pressure inside the cleaning processing apparatus is controlled by adjusting the balance between them. .

JP 2007-35866 A

  The inventors of the present invention conducted intensive research on the problems in the case of using such a single wafer cleaning apparatus, and found the following. The most serious problem when cleaning wafers is that the chemicals discharged to the rotating wafer bounce off the cup, and occur at the edge of the wafer when the wafer and table rotate. The turbulent flow causes chemical mist to adhere to the wafer and contaminate the wafer. If the chemical solution adheres to the wafer due to splashing of the scattered chemical solution or mist, it not only contaminates the wafer surface but also causes deterioration of the surface roughness of the wafer surface and causes of etching. Further, if pure water or ozone water adheres to the wafer, it causes a watermark.

  In the conventional single wafer cleaning processing equipment, the air volume and air speed at the air supply section and exhaust section are controlled. This is to control the pressure inside the equipment. not going.

  If the turbulent flow generated at the wafer edge is not controlled, even if the air speed and air volume at the air supply and exhaust sections are controlled, the chemical solution supplied during the rotation of the wafer and table will eventually scatter. The mist that hits the cup part adhered to the wafer and became a source of contamination such as particles, watermarks, and etching.

  In order to suppress this turbulent flow, if the wind speed at the air supply section or exhaust section is greatly increased, vortices are generated due to the cup structure and strong air flow, and mist rewinding occurs. It was.

  The present invention has been made in view of the above-described problems, and when a wafer is cleaned using a single wafer cleaning apparatus, a wafer caused by a mist of a chemical solution generated due to the influence of turbulent flow. It is an object of the present invention to provide a single wafer cleaning apparatus and a wafer cleaning method capable of suppressing surface defects.

In order to achieve the above object, the present invention includes a cup portion disposed in a chamber, a table portion disposed in the cup portion for holding and rotating the wafer, and a nozzle portion for supplying a chemical to the wafer. A single wafer cleaning apparatus comprising:
An air supply section provided in the chamber;
A supply air volume variable mechanism for adjusting the air volume of the supply section;
An exhaust section provided in the chamber;
An exhaust air volume variable mechanism for adjusting the air volume of the exhaust part;
Provided is a single wafer cleaning apparatus characterized by comprising an anemometer for measuring an air velocity at a position of an end portion of a wafer held by the table portion.

  Thus, in the case of a single wafer type wafer cleaning processing apparatus equipped with an anemometer that measures the wind speed at the position of the wafer edge, the wind speed at the position of the edge of the wafer when not rotating is measured. The wind speed can be adjusted to an appropriate value by the air volume variable mechanism and the exhaust air volume variable mechanism. Then, the cleaning process can be performed while rotating the wafer in the adjusted state. As a result, generation of turbulent flow during cleaning at the position of the edge of the wafer and roll-up of mist due thereto can be suppressed, and defects due to adhesion of mist or the like occur on the wafer surface during cleaning processing. This can be prevented.

  At this time, the anemometer is preferably retractable from the measurement position at the end of the wafer.

  In this way, if the anemometer can be retracted, the anemometer should be retracted from the measurement position at the edge of the wafer before starting the wafer cleaning process so that the scattered chemical does not hit the anemometer. It is possible to more reliably prevent the chemical solution from bouncing off from the anemometer. Furthermore, it can prevent more reliably that a chemical | medical solution adheres to an anemometer and influences a wind speed measurement.

  At this time, it is preferable that the single wafer cleaning apparatus further includes a pressure gauge for measuring a differential pressure inside and outside the chamber.

  By providing such a pressure gauge, the pressure difference inside and outside the chamber can be measured, and the pressure inside the chamber can be compared with the pressure outside the chamber by adjusting the supply air volume variable mechanism and the exhaust air volume variable mechanism. It can be within an appropriate range. That is, it is possible to prevent the inside of the chamber from becoming an excessive negative pressure or a positive pressure, and it is possible to more effectively prevent defects from occurring on the wafer surface due to them.

In order to achieve the above object, the present invention has a cup portion arranged in a chamber, and holds a chemical solution from a nozzle portion on a wafer held and rotated by a table portion arranged in the cup portion. A wafer cleaning processing method for cleaning the wafer in a single wafer manner while supplying,
The chamber is adjusted so that the wind speed is 1.0 m / sec or more while measuring the wind speed at the position of the end of the wafer held by the table section with the anemometer when the table section is not rotating. A wafer cleaning method, wherein the wafer is cleaned while rotating the table unit in a state where at least one of an air flow rate for supplying air into the chamber and an air flow rate for exhausting the chamber outside is adjusted. provide.

  Thus, the wind speed at the position of the edge of the wafer when not rotating can be adjusted so that the wind speed is 1.0 m / sec or more while measuring the wind speed with the anemometer. If the cleaning process is performed while rotating the wafer in an adjusted state, the generation of turbulent flow during cleaning and the resulting mist roll-up can be suppressed. Generation of defects due to adhesion can be prevented.

  At this time, it is preferable that the anemometer is retracted from the measurement position at the end of the wafer after the measurement of the wind speed and before cleaning the wafer.

  In this way, by retracting the anemometer from the measurement position before cleaning the wafer, it is possible to prevent the scattered chemical from hitting the anemometer, and more reliably preventing the chemical from splashing from the anemometer. can do. Furthermore, it can prevent more reliably that a chemical | medical solution adheres to an anemometer and influences a wind speed measurement.

  At this time, when adjusting the wind speed at the position of the end of the wafer, it is preferable that the pressure difference between the inside and outside of the chamber is within a range of 0 to 5 Pa.

  In this way, by setting the differential pressure inside and outside the chamber within the range of 0 to 5 Pa, the inside of the chamber does not become excessive negative pressure or positive pressure, and defects caused by the negative pressure or positive pressure are caused on the wafer surface. Generation | occurrence | production can be prevented more effectively.

  As described above, according to the single wafer cleaning apparatus and the wafer cleaning processing method of the present invention, it is possible to prevent the mist from adhering to the wafer due to the turbulent flow generated at the edge of the wafer when the wafer rotates. The increase in the number of defects on the wafer surface due to the above can be effectively suppressed.

It is the schematic which shows an example of the single wafer type wafer cleaning processing apparatus of this invention. It is a graph which shows the relationship between the wind speed of the position of the edge part of a wafer, and the number of increase defects by an Example and a comparative example.

  Hereinafter, the present invention will be described in detail as an example of embodiments with reference to the drawings. However, the present invention is not limited to these.

  First, a single wafer cleaning apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing an example of a single wafer cleaning apparatus according to the present invention.

  A single wafer cleaning apparatus 100 in FIG. 1 includes a chamber 1, a cup portion 2, an air supply portion 3 provided in the chamber 1, and an air supply air volume variable mechanism 4 that adjusts the air volume of the air supply portion 3. The exhaust unit 5 provided in the chamber 1, the exhaust air volume variable mechanism 6 that adjusts the air volume of the exhaust unit 5, the table unit 7 that holds and rotates the wafer W, and the chemical solution 13 is supplied to the wafer W. And an anemometer 9 that measures the wind speed at the position of the end of the wafer W held on the table section 7. Further, the single wafer cleaning apparatus 100 includes a pressure gauge 10 that measures the differential pressure inside and outside the chamber, and a mechanism that can retract the anemometer 9 from the position of the end portion of the wafer W (anemometer retraction). Mechanism) 11.

  The chamber 1 is a casing that constitutes the single wafer cleaning apparatus 100, and houses the cup part 2, the table part 7, the nozzle part 8, and the like. The cup unit 2 is provided in the chamber, and is used to collect or drain the chemical solution 12 scattered around by the rotation of the wafer W, and is provided so as to surround the wafer W. As shown in FIG. 1, the cup portion 2 has a portion inclined inward at the top, and the angle of the inclined portion with the horizontal is, for example, 15 to 30 °. be able to.

  The air supply unit 3 is provided in the upper part of the chamber 1 and has a function of supplying air (air) whose temperature and humidity are controlled, for example, into the chamber 1. However, the gas supplied from the air supply unit 3 into the chamber 1 is not limited to air. The supply air volume varying mechanism 4 has a function of adjusting the air volume (and / or wind speed) of the gas supplied into the chamber 1 by the air supply unit 3. The supply air volume variable mechanism 4 can be in the form of a fan, for example, and the air volume can be adjusted by increasing or decreasing the rotation speed of the fan, but is not limited to the fan form. .

  The exhaust unit 5 is provided in the lower part of the chamber 1 and has a function of exhausting the chamber 1. The exhaust air volume variable mechanism 6 is provided in the exhaust section 5, for example, a duct of the exhaust section 5, and has a function of adjusting the exhaust air volume (and / or wind speed) in the exhaust section 5. The exhaust air volume variable mechanism 6 can be in the form of a damper, for example, and the air volume of the exhaust section 5 can be adjusted by controlling the opening and closing of the damper, but is limited to the form of the damper. is not.

  The table unit 7 includes a table 14 that is rotationally driven and a plurality of holding pins 15 provided on the table 14, and the holding pins 15 hold the wafer W from the outer peripheral side. The nozzle unit 8 may be provided above the wafer W, and may have a plurality of nozzles that supply, for example, a chemical solution such as hydrofluoric acid, ozone water, and pure water to the main surface of the wafer W.

  The anemometer 9 is provided so that the wind speed measurement position is located at the end of the wafer W. At the position of the end portion of the wafer W, turbulence is generated when the wafer W and the table portion 7 are rotated (during cleaning). The anemometer 9 can accurately measure the wind speed when the table portion 7 is not rotating at the position where turbulent flow is generated during cleaning (when not cleaning). For example, a hot-wire anemometer can be used as the anemometer 9, but the anemometer 9 is not limited to this.

  Thus, since the anemometer 9 is provided, the wind speed at the end portion of the wafer W is accurately measured at the time of non-cleaning, and the wind speed is adjusted by the supply air volume variable mechanism 4 and the exhaust air volume variable mechanism 6. It can be adjusted to an appropriate value. The appropriate air speed value at the time of non-cleaning referred to here is the end of the wafer W even if cleaning is started (the table section 7 is rotated) under the condition of the air speed (air supply air volume, exhaust air volume, etc.). It means a value that does not generate turbulence. Thereby, generation | occurrence | production of a turbulent flow at the time of washing | cleaning and roll-up (rewinding) of mist etc. by it can be suppressed, and it prevents that the defect by mist etc. generate | occur | produces on the surface of the wafer W at the time of a cleaning process. Can do.

  The anemometer 9 can be configured such that the position and height can be adjusted. Further, the anemometer 9 can be retracted manually or automatically to a position (standby position) where the scattered chemical liquid 12 does not hit by the anemometer retracting mechanism 11. If the anemometer 9 remains fixed at the position of the end of the wafer W, the chemical solution 12 scattered from the wafer W may hit the anemometer 9 during the cleaning process of the wafer W. By moving the anemometer 9 to the standby position by the anemometer retracting mechanism 11, it is possible to more reliably prevent the splashed chemical solution 12 from being bounced by the anemometer 9. Furthermore, it is possible to prevent the chemical solution 12 scattered on the anemometer 9 from adhering and affecting the subsequent wind speed measurement. The anemometer retracting mechanism 11 can be, for example, a robot arm that can move in a plurality of directions. Alternatively, the anemometer retracting mechanism 11 may be a simple one that can be moved manually or automatically only in a specific direction such as the upward direction in FIG. The anemometer 9 may be removable from the wind speed measurement position, and may be detached from the single wafer cleaning apparatus 100 after the measurement and adjustment of the wind speed are completed.

  The adjustment of the air velocity at the position of the end of the wafer W is performed by adjusting the balance between the supply of air into the chamber 1 by the supply air volume variable mechanism 4 and the exhaust from the chamber 1 by the exhaust air volume variable mechanism 6. be able to. The adjustment of the wind speed can be performed by manually adjusting the supply air volume variable mechanism 4 and the exhaust air volume variable mechanism 6, and the value of the wind speed is set and the supply air volume is set so that the wind speed becomes that value. The variable mechanism 4 and the exhaust air volume variable mechanism 6 can be automatically controlled. Furthermore, it is also possible to perform control that combines manual and automatic adjustment.

  The single wafer cleaning apparatus 100 may further include a pressure gauge 10 that measures a differential pressure inside and outside the chamber 1. The pressure gauge 10 may have a pressure detection part inside and outside the chamber 1, thereby obtaining a differential pressure. Alternatively, for example, when the single wafer cleaning apparatus 100 is installed in a clean room or the like having a predetermined pressure, only the pressure inside the chamber 1 is measured, and the measured pressure inside the chamber and outside the predetermined chamber are measured. The differential pressure may be obtained by comparing the pressures.

  Here, when the inside of the chamber 1 is excessively negative pressure (negative pressure), inflow of outside air into the chamber 1 occurs, which may be a source of contamination such as particles. On the other hand, when the inside of the chamber 1 is excessively positive, the generated mist may be rolled up by the gas supplied from the air supply unit and attached to the wafer without being exhausted, thereby becoming a contamination source. The pressure gauge 10 can adjust the pressure difference between the inside and outside of the chamber 1 within an appropriate range, and if cleaning is performed in this state, a contamination source to the wafer W due to excessive negative pressure or positive pressure inside the chamber 1. It is possible to more reliably prevent the adhesion and the occurrence of defects.

Next, the wafer cleaning processing method of the present invention will be described with reference to FIG.
The wafer cleaning processing method of the present invention is, for example, a wafer cleaning processing method using the single wafer cleaning process 100 shown in FIG. In the wafer cleaning method of the present invention, when the table portion 7 is not rotating, the wind velocity at the position of the end portion of the wafer W held on the table portion 7 is measured by the anemometer 9 while the wind velocity is 1. One or more of the air volume of the supply air into the chamber 1 and the air volume of the exhaust gas outside the chamber 1 are adjusted by the corresponding supply air volume variable mechanism 4 and exhaust air volume variable mechanism 6 so as to be 0 m / sec or more. In this state, the wafer W is cleaned while rotating the table unit 7.

  Here, the timing for measuring and adjusting the wind speed at the end portion of the wafer W is when the wafer W is not rotating, in which no turbulent flow occurs, but is adjusted to a wind speed of 1.0 m / sec or more. As a result, the number of increased defects in the cleaned wafer can be sufficiently reduced. This is because the wind speed measurement position is the same position as the turbulent flow generation position, and therefore there is a certain correlation between the wind speed value when the wafer W is not rotating and the turbulent flow generation status (whether or not generated). It is guessed.

  Moreover, although the upper limit of the wind speed at the position of the end portion of the wafer W is not particularly limited, it can be, for example, in the range of 1.0 to 5.0 m / sec. From the upper limit on the apparatus, 5.0 m / sec is sufficient, and when the wind speed is 5.0 m / sec or less, the number of increased defects can be more effectively suppressed. For this reason, when the wind speed is 5.0 m / sec or less, mist rewind due to vortex generation, mist entrainment due to air current, and defects on the wafer surface due to them are hardly generated.

  Further, it is preferable that the anemometer 9 is retracted from the measurement position at the end of the wafer W after the measurement of the wind speed and before the wafer W is cleaned. By retracting the anemometer 9 to a position where the scattered chemical liquid 12 does not hit, it is possible to more reliably prevent the chemical liquid from rebounding from the anemometer 9 and the chemical liquid from adhering to the anemometer 9.

  Further, when adjusting the wind speed at the position of the end of the wafer W, it is preferable to set the differential pressure inside and outside the chamber 1 within the range of 0 to 5 Pa. By setting it as the range of such differential pressure | voltage, it can prevent that the inside of the chamber 1 becomes an excessive negative pressure or a positive pressure. Therefore, it is possible to more reliably prevent the contamination source from adhering to the wafer W due to excessive negative pressure or positive pressure and the occurrence of defects.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these.

(Example)
Using the single wafer cleaning apparatus 100 of the present invention shown in FIG. 1, 100 mirror-polished silicon wafers having a diameter of 300 mm are cleaned under one condition, and the number of defects on the surface of each silicon wafer is measured before and after cleaning. The number of defects increased by cleaning was determined. The measurement and adjustment of the wind speed at the position of the end of the silicon wafer are performed by adjusting the supply air volume into the chamber 1 and the chamber 1 by the supply air volume variable mechanism 4 and the exhaust air volume variable mechanism 6 when the table portion 7 is not rotating. This was done by adjusting the air volume of the exhaust to the outside. Then, the silicon wafer was cleaned in the adjusted state.

  The cleaning is a general cleaning using ozone water and hydrofluoric acid, and the cleaning flow is a flow in which ozone water, pure water, hydrofluoric acid, pure water, ozone water, pure water, and drying are performed in this order. The number of rotations was 1500 rpm.

  The number of defects on the surface of the silicon wafer was measured using Surfscan SP3 manufactured by KLA-Tencor. The wind speed was measured using an anemo master anemometer manufactured by Nippon Kanomax.

  The wind speed at the time of non-cleaning at the end of the silicon wafer is 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, and 2.2 m / sec, respectively. Adjustments were made to determine the number of increased defects on the silicon wafer surface under these seven conditions. The results are shown in the right part of FIG. FIG. 2 is a graph in which the horizontal axis represents the wind velocity at the edge of the wafer and the vertical axis represents the increased number of defects, and the increased number of defects under each condition is the average value of the increased number of defects for 100 silicon wafers. It is. Further, in FIG. 2, the maximum value and the minimum value of the increased number of defects of 100 wafers under each condition are shown together with bold lines. If the wind speed at the edge of the wafer is 1.0 m / sec or more, the number of increased defects is sufficiently suppressed, and the variation in the number of increased defects (the difference between the maximum value and the minimum value, that is, the range) is also achieved. It was suppressed. Thus, by adjusting the wind speed at the edge of the wafer during non-cleaning to be 1.0 m / sec or higher, the increase in the number of defects due to adhesion of mist or the like to the wafer during cleaning is significantly reduced. It was done.

(Comparative example)
In order to compare the wind speed and the number of defects with the example, as in the example, using a single wafer cleaning apparatus 100 of the present invention shown in FIG. 100 were washed, the number of defects on the surface of the silicon wafer was measured before and after washing, and the number of increased defects was determined. The wind speed was measured and adjusted when the silicon wafer was not rotating, and the silicon wafer was cleaned in the adjusted state. Except for the conditions relating to the wind speed value, it was the same as that described in the examples, and the anemometer was also the same as in the examples.

And the wind speed of the position of the edge part of a silicon wafer was adjusted so that it might become 0.4, 0.6, and 0.8 m / sec, respectively, and the number of increase defects of the silicon wafer in these three conditions was calculated. .
The results are shown in Table 1 and FIG.

  The wind speed in Table 1 is the wind speed measured at the position of the end of the wafer W when the wafer W is not rotating. Then, as described above, when the wafer W is not rotated, the supply air volume variable mechanism 4 and the exhaust air volume variable mechanism 6 are adjusted to obtain the respective wind speeds shown in Table 1. In Table 1, the number of increased defects is an average value for 100 silicon wafers calculated by subtracting the number of defects on the wafer surface measured before the cleaning process from the number of defects on the wafer surface measured after the cleaning process. It is.

  From Table 1 and FIG. 2, the results of Examples and Comparative Examples were compared. As in the comparative example, when the wind speed was 0.4 m / sec, the number of increased defects was as large as 38, and the variation in the increased number of defects was extremely large. Although the number of increased defects is reduced at wind speeds of 0.6 and 0.8 m / sec as compared with 0.4 m / sec, the number of increased defects and variations are compared with those of the wind speed of 1.0 m / sec or more in the examples. The inhibitory effect was not sufficient.

  On the other hand, when the wind speed of the embodiment is 1.0 m / sec or more, the number of increased defects is reduced to almost one level. As described above, by setting the wind speed at the end portion of the wafer W to 1.0 m / sec or more, it is possible to surely obtain a remarkable effect of suppressing the number of increased defects.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

DESCRIPTION OF SYMBOLS 1 ... Chamber, 2 ... Cup part, 3 ... Air supply part, 4 ... Supply air volume variable mechanism,
5 ... Exhaust part, 6 ... Exhaust air volume variable mechanism, 7 ... Table part, 8 ... Nozzle part,
9 ... Anemometer, 10 ... Pressure gauge, 11 ... Anemometer retraction mechanism, 12 ... Spattered chemical,
13 ... Chemical solution, 14 ... Table, 15 ... Holding pin,
100: Single wafer cleaning apparatus of the present invention, W: Wafer.

Claims (6)

A single wafer cleaning apparatus comprising a cup portion disposed in a chamber, a table portion disposed in the cup portion for holding and rotating the wafer, and a nozzle portion for supplying a chemical to the wafer. And
An air supply section provided in the chamber;
A supply air volume variable mechanism for adjusting the air volume of the supply section;
An exhaust section provided in the chamber;
An exhaust air volume variable mechanism for adjusting the air volume of the exhaust part;
A single wafer cleaning apparatus, comprising: an anemometer that measures an air velocity at a position of an end portion of a wafer held by the table portion.   The single wafer cleaning apparatus according to claim 1, wherein the anemometer is retractable from a measurement position at an end of the wafer.   The single wafer cleaning apparatus according to claim 1, further comprising a pressure gauge that measures a differential pressure inside and outside the chamber. A wafer having a cup portion disposed in a chamber and cleaning the wafer in a single wafer manner while supplying a chemical solution from a nozzle portion to a wafer held and rotated by a table portion disposed in the cup portion. A cleaning method,
The chamber is adjusted so that the wind speed is 1.0 m / sec or more while measuring the wind speed at the position of the end of the wafer held by the table section with the anemometer when the table section is not rotating. A wafer cleaning method, comprising: cleaning the wafer while rotating the table unit in a state where at least one of an air supply amount to the inside and an air flow amount to the outside of the chamber is adjusted.   5. The wafer cleaning method according to claim 4, wherein the anemometer is retracted from a measurement position at an end of the wafer after the measurement of the wind speed and before the wafer is cleaned. 6. 6. The wafer cleaning method according to claim 4, wherein, when adjusting the wind speed at the position of the end portion of the wafer, a pressure difference between the inside and outside of the chamber is set within a range of 0 to 5 Pa. 6. .

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