JP2006286665A - Method and apparatus for cleaning electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove fine particles sufficiently without causing any damage on the surface of an electronic device. <P>SOLUTION: An apparatus for cleaning an electronic device comprises a section 50 for supplying alkaline cleaning liquid, a section 40 for supplying high pressure air, and a two-fluid nozzle 30 for spraying the cleaning liquid to a semiconductor wafer W while mixing with high pressure air. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic device cleaning method and an electronic device cleaning apparatus for cleaning an electronic device such as a semiconductor wafer or a display, and more particularly to a device capable of removing particles without damaging a device pattern.

  The manufacturing process of a semiconductor device includes a process of forming a fine pattern by repeatedly performing processes such as film formation and etching on the surface of a semiconductor wafer. In order to form a fine pattern, it is necessary to keep both surfaces of the semiconductor wafer, particularly the thin film forming surface, clean, so that the semiconductor wafer is cleaned using a substrate cleaning apparatus. In such a substrate cleaning apparatus that performs a semiconductor wafer cleaning process, a two-fluid nozzle is used to atomize pure water with high-pressure air or high-pressure nitrogen, and the particles are removed by hitting the substrate (for example, Patent Documents). 1).

Similar to semiconductor wafers, electronic devices such as liquid crystal displays and PDP substrates are also cleaned using a similar cleaning apparatus.
JP 2002-270564 A

  The above-described semiconductor wafer cleaning method has the following problems. That is, in the method of removing particles by atomizing pure water with high-pressure air or high-pressure nitrogen, the particles once detached from the surface of the semiconductor wafer are transported and discharged in the liquid film on the semiconductor wafer. In some cases, the particles reattached to the surface and the particles could not be removed sufficiently. Also, when the pressure of pure water, high-pressure air or high-pressure nitrogen is increased to improve the particle removal rate, the device pattern formed on the surface of the semiconductor wafer is damaged, and there is a problem that is not suitable for actual use. It was.

  Therefore, an object of the present invention is to provide an electronic device cleaning method and an electronic device cleaning apparatus that can sufficiently remove fine particles without damaging the surface of the electronic device.

  In order to solve the above problems and achieve the object, an electronic device cleaning method and an electronic device cleaning apparatus of the present invention are configured as follows.

  A step of supplying alkaline cleaning water, a step of supplying high-pressure gas, and a step of making the supplied cleaning water mist by mixing the gas and spraying the electronic device. Features.

  Further, the cleaning water supplying means for supplying alkaline cleaning water, the high pressure gas supplying means for supplying high-pressure gas, and the supplied cleaning water are atomized by mixing the gas and sprayed on the electronic device. And a two-fluid nozzle.

  According to the present invention, it is possible to sufficiently remove fine particles without damaging the surface of the electronic device.

  FIG. 1 is an explanatory view showing the configuration of a substrate cleaning apparatus (electronic device cleaning apparatus) 10 according to an embodiment of the present invention, and FIGS. 2 to 5 are explanatory views showing the reason why an alkaline aqueous solution is used in the substrate cleaning apparatus 10. is there.

  The electronic device cleaning apparatus 10 includes a cleaning unit 20, a high-pressure air supply unit 40, a cleaning water supply unit 50, and a control unit 60 that controls these units in cooperation.

  The cleaning unit 20 is attached to the electric motor 21 controlled by the control unit 60, the rotating shaft 22 of the electric motor 21, the spin chuck 23 that holds the semiconductor wafer W, and the spin chuck 23. And a two-fluid nozzle 30. The two-fluid nozzle 30 includes a gas flow path 31 through which high-pressure air flows in a central portion, and a cleaning water path 32 that is disposed so as to surround the gas flow path 31 and through which cleaning water flows. The gas flow path 31 is connected to an air pipe 42 to be described later, and the cleaning water path 32 is connected to a cleaning water pipe 52 to be described later, and is configured to introduce high-pressure air and cleaning water, respectively. Further, the two-fluid nozzle 30 is supported so that the supply position of the cleaning water in the surface of the semiconductor wafer W can be changed by an elevating / moving mechanism (not shown).

  The high pressure air supply unit 40 includes a high pressure air generation unit 41, an air pipe 42 for sending high pressure air from the high pressure air generation unit 41 to the two-fluid nozzle 30, and a pressure adjustment unit provided in the middle of the air pipe 42. 43, a pressure sensor 44 for measuring the air pressure in the pressure adjusting unit 43, and a flow rate sensor 45 provided in the middle of the air pipe 42. The pressure adjustment unit 43 performs pressure adjustment according to an instruction from the control unit 60. The outputs of the pressure sensor 44 and the flow sensor 45 are input to the control unit 60.

  The cleaning water supply unit 50 includes a pure water supply tank 51, a cleaning water pipe 52 for sending cleaning water from the pure water supply tank 51 to the two-fluid nozzle 30, and a pressure provided in the middle of the cleaning water pipe 52. An adjustment unit 53, a pressure sensor 54 for measuring the washing water pressure in the pressure adjustment unit 53, a flow sensor 55 provided in the middle of the washing water pipe 52, and a pure water sensor provided in the middle of the washing water pipe 52. And an alkaline aqueous solution supply unit 56 that is used as washing water by adding an alkaline aqueous solution to water. The pressure adjustment unit 53 performs pressure adjustment according to an instruction from the control unit 60. The outputs of the pressure sensor 54 and the flow rate sensor 55 are input to the control unit 60.

  In addition, as alkali aqueous solution mentioned above, organic alkalis, such as ammonia, tetramethylammonium hydroxide, choline, hydroxylamine, are used. Furthermore, instead of the pure water supply tank 51, an alkaline aqueous solution supply tank that contains an alkaline aqueous solution in advance may be used, and the alkaline aqueous solution supply unit 56 may be omitted.

  In the substrate cleaning apparatus 10 configured as described above, the semiconductor wafer W is cleaned as follows. That is, the semiconductor wafer W is rotated by rotating the electric motor 21. The rotation speed at this time is about 500 rpm, for example. Further, the alkaline aqueous solution is added from the alkaline aqueous solution supply unit 56 to the pure water supplied from the pure water supply tank 51.

  Next, when the pressure adjusting units 43 and 53 are opened by a signal from the control unit 60 and air and cleaning water are supplied to the two-fluid nozzle 30, the cleaning water is atomized by the high-pressure air and is applied to the surface of the semiconductor wafer W. Sprayed. Thereby, particles are poured out. At this time, a control signal is sent from the control unit 60 to the pressure adjusting units 43 and 53, and the pressure of the air and the cleaning water is appropriately adjusted so that the cleaning water having a predetermined pressure is sprayed. At the same time, the results detected from the pressure sensors 44 and 54 and the flow rate sensors 45 and 55 are fed back to the controller 60 sequentially.

Here, the action when an alkaline water is used as the washing water will be described in detail. That is, a zeta potential is generated on the sliding surface (S in FIG. 2) in the wash water. This ζ potential varies depending on the material and varies depending on the pH of the washing water as shown in FIG. As a material of the semiconductor wafer W, SiN is formed on SiO ₂ and the particles P are alumina.

  On the other hand, the potential energy between the two substances is the sum of the intermolecular force and the electrostatic potential, and has a relationship as shown in FIG. That is, when the ζ potential has the same sign, it becomes a repulsive force, and when the ζ potential has a different sign, it becomes an attractive force. Therefore, in the case of alkaline (pH value of 8 or more), the ζ potential of each substance becomes negative, and an electric repulsion occurs between both substances as shown in FIG.

  Accordingly, both the surface potential of the semiconductor wafer W and the surface potential of the particles P are negative in the alkaline cleaning water, so that the reattachment of the particles P to the semiconductor wafer W is suppressed. Note that, by selecting the material of the surface of the semiconductor wafer W and the alkaline cleaning water to be used, it is possible to add the effect of removing the particles P by the light etching of the surface of the semiconductor wafer W.

  As described above, according to the electronic device cleaning method performed by the electronic device cleaning apparatus 10 according to the present embodiment, it is possible to prevent reattachment of particles once detached from the surface of the semiconductor wafer W. Can be removed. Therefore, it is not necessary to spray cleaning water with a strong pressure, and damage to the device pattern can be prevented.

  Here, an experimental example will be described. The semiconductor wafer W on which the 55 nm line / space pattern was formed was measured with a pattern inspection apparatus, and the number of defects was counted. The semiconductor wafer was cleaned by the substrate cleaning apparatus 10 under the following “condition 1” to “condition 3”.

  Condition 1 is pure water 0.2 MPa (100 ml / min), high-pressure air 0.2 MPa (60 L / min), and wafer rotation speed 500 rpm. Condition 2 is pure water 0.3 MPa (200 ml / min), high-pressure air 0.3 MPa (80 L / min), and wafer rotation speed 500 rpm. Condition 3 is 0.2 mmol / 1 ammonia water 0.2 MPa (100 ml / min), high-pressure air 0.2 MPa (60 L / min), and wafer W rotation speed 500 rpm.

  The semiconductor wafer W after the above processing was measured with a pattern inspection apparatus, and the number of defects was counted. Moreover, the increased defect was observed by review SEM and it was confirmed whether the pattern was damaged. As a result, the removal rate of particles counted as defects was 60% under condition 1, 80% under condition 2, and 85% under condition 3. Also, no damage to the pattern was observed under conditions 1 and 3, but damage was observed at 10 locations under condition 2. Therefore, it is preferable that the pressure of the washing water and the high-pressure air is 0.3 MPa or less. In consideration of the effect of cleaning, the pressure of the cleaning water and high-pressure air is preferably 0.1 MPa or more.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the structure of the board | substrate cleaning apparatus which concerns on one embodiment of this invention. Explanatory drawing which shows the reason for using alkaline aqueous solution in the board | substrate washing | cleaning apparatus. Explanatory drawing which shows the reason for using alkaline aqueous solution in the board | substrate washing | cleaning apparatus. Explanatory drawing which shows the reason for using alkaline aqueous solution in the board | substrate washing | cleaning apparatus. Explanatory drawing which shows the reason for using alkaline aqueous solution in the board | substrate washing | cleaning apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electronic device washing | cleaning apparatus, 20 ... Cleaning part, 30 ... Two-fluid nozzle, 40 ... High pressure air supply part, 50 ... Washing water supply part.

Claims (6)

Supplying alkaline washing water;
Supplying a high-pressure gas;
And a step of spraying the supplied cleaning water into the mist by mixing the gas and the electronic device.   The electronic device cleaning method according to claim 1, wherein the cleaning water contains ammonia.   The electronic device cleaning method according to claim 1, wherein the cleaning water contains an organic alkali.   The electronic device cleaning method according to claim 3, wherein the cleaning water contains at least one of tetramethylammonium hydroxide, choline, and hydroxylamine.   2. The electronic device cleaning method according to claim 1, wherein the pressure of the cleaning water and the gas is 0.1 MPa or more and 0.3 MPa or less. Cleaning water supply means for supplying alkaline cleaning water;
High-pressure gas supply means for supplying high-pressure gas;
An electronic device cleaning apparatus, comprising: a two-fluid nozzle that forms a mist by mixing the supplied cleaning water with the gas and blows the electronic device.

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