CN1691288A - Substrate cleaning apparatus and method - Google Patents

Abstract

The present invention provides a substrate cleaning device capable of sufficiently removing foreign matter adhering to the back surface of the substrate without damaging the substrate. A plasma processing apparatus (1) as a substrate cleaning apparatus includes: a chamber (10); a susceptor (11) disposed in the chamber (10) on which a wafer (W) is placed; disposed on the susceptor ( 11), Electrode plates (20) for applying high voltage; rough discharge lines for degassing the chamber (10); push pins for creating space (S) between susceptor (11) and wafer (W) (30); _N2 gas is supplied to the heat transfer gas supply hole (27) of the space (S), and the pouring head (33) that introduces processing gas etc. in the chamber 10, when generating the space S, the polarity Different high voltages are alternately applied to the electrode plate (20), N _gas is ejected to the space (S) toward the back side of the wafer (W), and the chamber (10) is exhausted, and then in the chamber (10) When the inside is depressurized, _N2 gas is introduced into the chamber (10).

Description

Substrate cleaning device and substrate cleaning method

technical field

The present invention relates to a substrate cleaning device and a substrate cleaning method, and more particularly, to a substrate cleaning device and a substrate cleaning method for removing foreign matter adhering to the back surface of a substrate subjected to plasma treatment.

Background technique

Generally, in the manufacturing process of a semiconductor device, a semiconductor wafer (hereinafter referred to as "wafer") as an object to be processed is subjected to plasma processing (hereinafter referred to as "wafer") such as etching or sputtering, CVD (chemical vapor phase growth), etc. plasma treatment').

For example, as shown in FIG. 8, a plasma processing apparatus 80 for performing an etching process includes a cylindrical container 81 for accommodating wafers, which is arranged inside the cylindrical container 81 as a carrier for placing wafers. The base 82 of the stage is opposed to the surface on which the wafer is placed (hereinafter referred to as "placement surface"), and is arranged so that the ejector pins 83 of the base 82 penetrate therethrough. The susceptor 82 has an electrostatic chuck 85 connected to an electrode of a DC power source 84 disposed on the mounting surface, and further has a lower electrode 87 connected to a high frequency power source 86 therein (for example, refer to Patent Document 1).

In the plasma processing device 80, after the electrostatic chuck 85 adsorbs the wafer on the mounting surface by the electrostatic adsorption force, high-frequency power is applied to the lower electrode 87, between the upper surface of the cylindrical container 81 and the base 82. A high-frequency electric field is generated to separate the processing gas introduced into the cylindrical container 81 to generate plasma. The generated plasma is condensed on the surface of the wafer by means of a condensing ring (not shown) arranged around the periphery of the wafer to etch the oxide film formed on the surface of the wafer.

In addition, the wafer subjected to the etching process is lifted from the mounting surface by the push pin 83, and is carried out from the cylindrical container 81 by a transfer device (not shown) such as a scalar arm entering the cylindrical container 81. .

Among the plasma generated in the etching process, those not collected on the surface of the wafer collide with the inner wall of the cylindrical container 81 to generate particles. In addition, during the etching process, reaction products are generated. Most of these particles or reaction products are exhausted from the cylindrical container 81 by an exhaust device (not shown), but a part of the particles or reaction products remaining in the cylindrical container 81 accumulates on the mounting surface. In addition, particles generated in the susceptor 82 due to plasma or the like are also deposited on the mounting surface. These particles or reaction products accumulated on the mounting surface adhere to the back surface of the wafer as foreign matter when the wafer is mounted on the mounting surface. Wet cleaning with a cleaning solution or the like is known as a method for removing such particles and reaction products adhering to the back surface of the wafer.

In addition, as a method that does not use cleaning liquid, plasma is generated between the wafer lifted by the push pin and the mounting surface, and the action of ion sputtering by the generated plasma, or the action of chemical reaction caused by radicals A method for removing particles on the back surface of a wafer is also known (for example, refer to Patent Document 2).

[Patent Document 1] Japanese Unexamined Patent Publication No. 5-226291 (Fig. 1)

[Patent Document 2] U.S. Patent No. 4,962,049 (line 67 of the second column to line 17 of the third column)

However, if wafer cleaning is repeated, the cleaning solution becomes contaminated. Therefore, there is a problem that the surface of the wafer is contaminated by particles or the like contained in the cleaning liquid contaminated during the cleaning of the wafer. In addition, when the wafer to which the etching process has been applied is carried into a subsequent chamber, unremoved particles may contaminate the interior of the chamber.

In addition, when plasma is used to remove particles on the back surface of the wafer, the generated plasma performs excessive plasma treatment on the wafer surface and damages the wafer. For example, there is a problem in that excessive etching is performed on the surface of the wafer and excessive etching occurs.

Contents of the invention

An object of the present invention is to provide a substrate cleaning device and a substrate cleaning method capable of sufficiently removing foreign matter adhering to the back surface of the substrate without damaging the substrate.

In order to achieve the above object, the substrate cleaning device according to technical solution 1 is characterized in that it is equipped with: a storage chamber for storing the substrate; a mounting table arranged in the storage chamber to mount the substrate; an electrode for adsorbing the substrate to the mounting table; an exhaust device for exhausting the chamber; a separation device for separating the mounting table from the substrate to create a space between the mounting table and the substrate; and The gas supply device for supplying gas to the space applies a voltage to the electrodes when the space is created, the gas supply device supplies gas to the space, and the exhaust device exhausts the storage chamber.

The substrate cleaning apparatus according to claim 2 is characterized in that, in the substrate cleaning apparatus according to claim 1, a gas that introduces the gas into the storage chamber when the pressure in the storage chamber is reduced and the space is created is further provided. import department.

The substrate cleaning device according to claim 3 is characterized in that, in the substrate cleaning device according to claim 1 or 2, a voltage is applied discontinuously to the electrodes.

The substrate cleaning device according to claim 4 is characterized in that, in the substrate cleaning device according to claim 3 , voltages with different polarities are alternately applied to the electrodes.

The substrate cleaning device according to claim 5 is characterized in that, in the substrate cleaning device according to claim 4 , the absolute value of the voltage is 500 V or more.

The substrate cleaning device according to claim 6 is characterized in that, in the substrate cleaning device according to claim 5 , the absolute value of the voltage is 2 kV or more.

The substrate cleaning device according to technical solution 7 is characterized in that, in the substrate cleaning device described in any one of technical solutions 1 to 6, when the aforementioned exhaust device generates the aforementioned space, the pressure in the aforementioned storage chamber Keep it above 133Pa.

The substrate cleaning device according to claim 8 is characterized in that, in the substrate cleaning device according to claim 7, the exhaust device maintains the pressure in the storage chamber at 1.33× when the space is created. In the range of 10 ³ to 1.33×10 ⁴ Pa.

In order to achieve the above object, the substrate cleaning apparatus according to claim 9 is characterized in that it includes: a storage chamber for storing the substrate; a mounting table arranged in the storage chamber on which the substrate is placed; Exhaust device; separation device for separating the mounting table and the substrate to create a space between the mounting table and the substrate, and contacting the substrate to apply voltage to the substrate; gas supply for supplying gas to the space device; and a gas introduction device for introducing gas into the aforementioned storage chamber, when the aforementioned space is generated, a voltage is applied to the aforementioned substrate, the aforementioned gas supply device supplies gas to the aforementioned space, and the aforementioned exhaust device exhausts the aforementioned storage chamber, and When the pressure in the storage chamber is reduced and the space is created, the gas introduction part introduces gas into the storage chamber.

In order to achieve the above object, the substrate cleaning method described in technical solution 10 is a substrate cleaning method for removing foreign matter adhering to the back surface of the substrate, which is characterized in that it includes: a storage step of storing the substrate in a storage chamber; A placing step of placing the mounting table arranged in the aforementioned storage chamber; a separating step of separating the aforementioned mounting table and the aforementioned substrate so as to create a space between the aforementioned mounting table and the aforementioned substrate; when creating the aforementioned space, applying a voltage to the placement a step of applying a voltage to the electrodes of the mounting table; a gas supply step of supplying gas to the space when the space is created; and an exhaust step of exhausting the air in the housing when the space is created.

The method for cleaning a substrate according to claim 11 is characterized in that, in the method for cleaning a substrate according to claim 10 , further comprising a gas introduction method for introducing gas into the storage chamber when the pressure in the storage chamber is reduced and the space is created. step.

The substrate cleaning method according to claim 12 is characterized in that, in the substrate cleaning method according to claim 10 or 11, in the voltage applying step, a voltage is applied discontinuously to the electrodes.

The substrate cleaning method according to claim 13 is characterized in that, in the substrate cleaning method according to claim 12, in the voltage applying step, voltages with different polarities are alternately applied to the electrodes.

In order to achieve the above object, the substrate cleaning method described in technical solution 14 is a substrate cleaning method for removing foreign matter adhering to the back surface of the substrate, which is characterized in that it includes: a storage step of storing the substrate in a storage chamber; a step of placing on a stage arranged in the storage chamber; a step of separating the stage and the substrate so as to create a space between the stage and the substrate; when creating the space, applying a voltage to A step of applying a voltage to the substrate; a gas supply step of supplying gas to the space when the space is created; an exhaust step of exhausting the inside of the storage room when the space is created; and depressurizing and A gas introducing step of introducing gas into the aforementioned storage chamber when the aforementioned space is generated.

If the substrate cleaning device described in claim 1 is used, when a space is created between the mounting table and the substrate, a voltage is applied to the electrodes arranged on the mounting table, so an electrostatic field is generated in the space and electrostatic stress acts on the substrate. The back. Thereby, the foreign matter adhering to the back surface of the substrate is detached. In addition, when the above-mentioned space is created, gas is supplied to the space and the storage chamber is exhausted, so an airflow is generated in the space, and the detached foreign objects are discharged from the space by the airflow, and then exhausted from the storage chamber. Therefore, the substrate cleaning apparatus can sufficiently remove foreign matter adhering to the back surface of the substrate without damaging the substrate.

According to the substrate cleaning device according to claim 2, since the gas is introduced into the storage chamber when the storage chamber is depressurized, a traveling shock wave is generated in the storage chamber, and foreign matter adhering to the back surface of the substrate is separated into the space by the shock wave. Therefore, foreign matter adhering to the back surface of the substrate can be efficiently removed without damaging the substrate.

According to the substrate cleaning device according to claim 3, since the voltage is applied discontinuously to the electrodes, the application of the voltage to the substrate is repeated. Thus, electrostatic stress repeatedly acts on the back surface of the substrate. Therefore, foreign matter adhering to the back surface of the substrate can be more sufficiently removed.

According to the substrate cleaning device according to claim 4, since voltages with different polarities are alternately applied, electrification of the substrate can be prevented. When the substrate is charged, the electrical stress acting on the back surface of the substrate due to the application of the voltage is reduced. Therefore, by preventing the electrification of the substrate, it is possible to prevent a reduction in the removal efficiency of foreign matter adhering to the back surface of the substrate.

According to the substrate cleaning device described in claim 5, since the voltage applied to the electrode is 500 V or more when the space is created, the electrical stress acting on the back surface of the substrate can be increased, and the foreign matter can be reliably detached.

If the substrate cleaning device described in claim 6 is used, since the above-mentioned voltage is 2 kV or more, the above-mentioned electrostatic stress can be further increased.

If the substrate cleaning device described in claim 7 is used, since the exhaust device maintains the pressure in the storage chamber at 133 Pa or higher, a viscous flow with a large gas viscous force can be generated in the space. The foreign matter detached from the back surface of the substrate is drawn into the viscous flow and exhausted from the storage chamber together with the gas in the storage chamber. Thus, foreign matter adhering to the back surface of the substrate can be reliably removed.

According to the substrate cleaning device according to claim 8, since the exhaust device maintains the pressure in the storage chamber within the range of 1.33×10 ³ to 1.33×10 ⁴ Pa, viscous flow can be reliably generated in the space.

If the substrate cleaning device described in technical scheme 9 is used, since the separation device applies a voltage to the substrate when a space is generated between the mounting table and the substrate, an electrostatic field is generated in the space and electrostatic stress acts on the back surface of the substrate. . Thereby, the foreign matter adhering to the back surface of the substrate is detached. Furthermore, when a space is created and the chamber is decompressed, the gas introduction unit introduces gas into the chamber, so a traveling shock wave is generated in the chamber, and foreign matter adhering to the back surface of the substrate escapes into the space by the shock wave. In addition, when the above-mentioned space is created, gas is supplied into the space and the storage chamber is exhausted, so an airflow is generated in the space, and the detached foreign matter is discharged from the space by the airflow, and then exhausted from the storage chamber. Therefore, the substrate cleaning apparatus can sufficiently remove foreign matter adhering to the back surface of the substrate without damaging the substrate.

If the substrate cleaning method described in claim 10 is used, since a voltage is applied to electrodes provided on the mounting table when a space is generated between the mounting table and the substrate, an electrostatic field is generated in the space and electrostatic stress acts on the substrate. The back. Thereby, the foreign matter adhering to the back surface of the substrate is detached. In addition, when the above-mentioned space is created, gas is supplied into the space and the storage chamber is exhausted, so an airflow is generated in the space, and the detached foreign objects are discharged from the space by the airflow, and then exhausted from the storage chamber. Therefore, foreign matter adhering to the back surface of the substrate can be sufficiently removed without damaging the substrate.

If the substrate cleaning method described in claim 11 is used, since the gas is introduced into the storage chamber when the above-mentioned space is generated and the storage chamber is decompressed, a traveling shock wave is generated in the storage chamber, and the foreign matter adhering to the back surface of the substrate is moved by the shock wave. Get out of space. Therefore, foreign matter adhering to the back surface of the substrate can be efficiently removed without damaging the substrate.

According to the substrate cleaning method described in claim 12, since the voltage is applied discontinuously to the electrodes, the application of the voltage to the substrate is repeated. Thus, electrostatic stress repeatedly acts on the back surface of the substrate. Therefore, foreign matter adhering to the back surface of the substrate can be more sufficiently removed.

According to the substrate cleaning method described in claim 13, since voltages with different polarities are alternately applied, electrification of the substrate can be prevented. When the substrate is charged, the electrical stress acting on the back surface of the substrate due to the application of the voltage is reduced. Therefore, by preventing the electrification of the substrate, it is possible to prevent a reduction in the removal efficiency of foreign matter adhering to the back surface of the substrate.

According to the substrate cleaning method described in claim 14, since a voltage is applied to the substrate when a space is created between the stage and the substrate, an electrostatic field is generated in the space and electrostatic stress acts on the back surface of the substrate. Thereby, the foreign matter adhering to the back surface of the substrate is detached. Furthermore, when a space is created and the chamber is depressurized, gas is introduced into the chamber, so a traveling shock wave is generated in the chamber, and foreign matter adhering to the back surface of the substrate escapes into the space by the shock wave. In addition, when the above-mentioned space is created, gas is supplied into the space and the storage chamber is exhausted, so an airflow is generated in the space, and the detached foreign matter is discharged from the space by the airflow, and then exhausted from the storage chamber. Therefore, foreign matter adhering to the back surface of the substrate can be sufficiently removed without damaging the substrate.

Description of drawings

1 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus as a substrate cleaning apparatus according to a first embodiment of the present invention.

FIG. 2 is a sequence diagram of a substrate cleaning process performed in the plasma processing apparatus of FIG. 1 .

3 is a diagram showing a schematic configuration of a push pin in a plasma processing apparatus as a substrate cleaning apparatus according to a second embodiment of the present invention.

4 is a cross-sectional view showing a schematic configuration of a substrate cleaning apparatus according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a schematic configuration of a substrate processing system disposed in the substrate processing apparatus of FIG. 4 .

Fig. 6 is a diagram schematically showing the situation of removing particles from the back side of the wafer in an embodiment of the present invention. Fig. 6(a) schematically shows that +2kV and Figure 6(b) is a diagram schematically showing the situation of the space S after a few seconds have elapsed from FIG. 6(a), and FIG. 6(c) is a diagram schematically showing A diagram of the state of the space S after a few seconds have elapsed from FIG. 6( b ).

Fig. 7 is a graph showing observation results of particle removal in Examples of the present invention.

FIG. 8 is a diagram showing a schematic configuration of a conventional plasma processing apparatus for etching a wafer.

Explanation of symbols: 1, 56 plasma processing device; 10, 43 chamber; 11 base; 12, 65 exhaust path; 13 partition; 14APC (automatic pressure control valve); 15TMP (turbomolecular pump); 16, 46DP (dry pump); 17, 45 exhaust pipe; 18 high-frequency power supply; 19 matcher; 20, 35, 47 electrode plate; 22, 41, 48 DC power supply; 24 gathering ring; 25 cooling medium chamber; 26 piping; 27 heat transfer gas supply hole; 28 heat transfer gas supply line; 29 heat transfer gas supply pipe; 30, 40 push pins; 37 buffer chamber; 38 processing gas introduction pipe; 39 magnet; 42 substrate cleaning device; 44 worktable; 49 gas supply hole; 50 gas supply line; 51 pin; 54 gas introduction pipe; 55 substrate processing system; 57 , 62 transfer arm; 58 load lock chamber; 59 processing station; 60 load port; 61 positioner; 63 load unit; 64 gas supply pipe.

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, a plasma processing apparatus as a substrate cleaning apparatus according to a first embodiment of the present invention will be described in detail.

1 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus as a substrate cleaning apparatus according to a first embodiment of the present invention.

In FIG. 1, a plasma processing apparatus 1 constituted as an etching processing apparatus for performing etching processing on a wafer W has a metal, for example, a cylindrical chamber (accommodating chamber) 10 made of aluminum or stainless steel. Inside 10, a cylindrical susceptor (mounting table) 11 as a table on which the wafer W is placed is provided.

Between the side wall of the chamber 10 and the susceptor 11 is formed an exhaust passage 12 that functions as a flow passage for exhausting gas above the susceptor 11 to the outside of the chamber 10 . A ring-shaped baffle 13 is arranged in the middle of the exhaust passage 12, and the space downstream of the exhaust passage 12 compared with the baffle 13 communicates with an automatic pressure control valve (automatic pressure control valve) which is a variable butterfly valve. ) (hereinafter referred to as 'APC')14. The APC 14 is connected to a turbomolecular pump (hereinafter referred to as 'TMP') 15 as an exhaust pump for vacuuming, and further connected to a dry pump (hereinafter referred to as 'DP') 16 as an exhaust pump via the TMP 15. Although the exhaust flow path composed of APC 14, TMP 15 and DP 16 is referred to as a 'main discharge line' below, this main discharge line is not only controlled by the APC 14 in the chamber 10 but also by the TMP 15 and DP16. The inside of the chamber 10 is decompressed to a nearly vacuum state.

In addition, the space downstream of the partition plate 13 in the exhaust passage 12 is connected to an exhaust flow passage (hereinafter referred to as "rough exhaust line") (exhaust device) separate from the main exhaust line. Connect this coarse discharge line with the above space and DP 16. An exhaust pipe 17 having a diameter of, for example, 25 mm, and a valve V2 provided in the middle of the exhaust pipe 17 are provided. This valve V2 can isolate the above space from DP 16. The coarse exhaust line is used to exhaust the air in the chamber 10 from the DP 16.

A high-frequency power source 18 for plasma generation is electrically connected to the susceptor 11 via a matching unit 19 . This high frequency power supply 18 applies a predetermined high frequency, for example, high frequency power of 13.56 MHz to the base 11 . Thereby, the susceptor 11 functions as a lower electrode.

On the inside of the susceptor 11, a disc-shaped electrode plate 20 made of a conductive film is arranged to attract the wafer W by electrostatic attraction. The DC power supply 22 is electrically connected to the electrode plate 20 .

The wafer W is attracted and held on the susceptor 11 by Coulomb force or Johnson-Rahbek force generated by the DC voltage applied from the DC power source 22 to the electrode plate 20 . In addition, an annular focusing ring 24 made of silicon (Si) or the like focuses plasma generated above susceptor 11 on wafer W. As shown in FIG.

In addition, inside the susceptor 11, for example, an annular coolant chamber 25 extending in the circumferential direction is provided. In this cooling medium chamber 25, a cooling medium of a predetermined temperature, such as cooling water, is circulated from a cooling unit (not shown) through a pipe 26, and the processing temperature of the wafer W on the susceptor 11 is controlled by the temperature of the cooling medium. .

A plurality of heat transfer gas supply holes (gas supply means) 27 are opened in the upper surface of the susceptor 11 where the wafer W is adsorbed. These heat transfer gas supply holes 27 communicate with a heat transfer gas supply pipe 29 having a valve V3 via a heat transfer gas supply line 28 arranged inside the susceptor 11, and supply heat transfer gas from the heat transfer gas supply pipe 29 connected to the base 11. A heat transfer gas (not shown), for example, He gas, is supplied to the gap between the upper surface of the susceptor 11 and the rear surface of the wafer W. This improves the heat transfer between the wafer W and the susceptor 11 . Furthermore, the valve V3 can block the heat transfer gas supply hole 27 and the heat transfer gas supply part.

In addition, a plurality of ejector pins (separating means) 30 as lift pins protruding freely from the upper surface of the susceptor 11 are arranged on the portion where the wafer W is adsorbed on the upper surface of the susceptor 11 . These push pins 30 are converted into linear motion by a ball screw or the like by a motor (not shown) in rotation, and move vertically in the figure. When the wafer W is adsorbed and held on the upper surface of the susceptor 11, the push pins 30 are accommodated in the susceptor 11. The upper surface of the wafer W lifts away from the susceptor 11 and lifts up. At this time, a space S is formed between the upper surface of the susceptor 11 and the rear surface of the wafer W. As shown in FIG.

On the side wall of the chamber 10, a gate valve 32 for opening and closing the loading and unloading port 31 of the wafer W is attached. In addition, on the ceiling of the chamber 10, a shower head 33 serving as an upper electrode at a ground potential is disposed. Thereby, the high-frequency voltage from the high-frequency power supply 18 is applied between the susceptor 11 and the shower head 33 .

The shower head 33 at the top of the chamber includes a lower electrode plate 35 having a plurality of vent holes 34, and an electrode support 36 detachably supporting the electrode plate 35. In addition, a buffer chamber 37 is provided inside the electrode support 36 , and a processing gas introduction pipe 38 from a processing gas supply unit (not shown) is connected to the buffer chamber 37 . A valve V1 is disposed in the middle of the processing gas introduction pipe 38 . This valve V1 can isolate the buffer chamber 37 from the processing gas supply unit. In addition, around the chamber 10, a ring-shaped or concentrically extended magnet 39 is disposed.

In the chamber 10 of the plasma processing device 1, the magnet 39 forms a horizontal magnetic field in a certain direction, and a high-frequency voltage applied between the susceptor 11 and the pouring head 33 forms a vertical RF electric field, Accordingly, magnetron discharge is performed through the process gas in the chamber 10 , and high-density plasma is generated from the process gas in the vicinity of the surface of the susceptor 11 .

In this plasma processing apparatus 1 , at the time of etching, first, the gate valve 32 is opened, and the wafer W to be processed is carried into the chamber 10 and placed on the susceptor 11 . Then, the processing gas (for example, a mixed gas composed of C ₄ F ₈ gas, O ₂ gas and Ar gas at a prescribed flow ratio) is introduced into the chamber 10 from the pouring head 33 at a prescribed flow rate and a flow ratio, and the The APC 14 and the like make the pressure in the chamber 10 a predetermined value. Further, high-frequency power is supplied to susceptor 11 from high-frequency power supply 18 , and DC voltage is applied to electrode plate 20 from DC power supply 22 to attract wafer W on susceptor 11 . Then, the processing gas ejected from the shower head 33 is plasma-formed as described above. Radicals or ions generated in the plasma are collected on the surface of the wafer W by the focusing ring 24 to etch the surface of the wafer W.

In the plasma processing apparatus 1 described above, among the generated plasma, those not collected on the surface of the wafer W collide with the inner wall of the chamber 10 or the like to generate particles. Among the generated particles, those not discharged by the main discharge line or the rough discharge line are accumulated on the upper surface of the susceptor 11 . The particles deposited on the upper surface adhere to the back surface of the wafer W as foreign matter when the wafer W is placed on the upper surface of the susceptor 11 . Accordingly, in the plasma processing apparatus 1, when the wafer W is etched by the push pin 30 to separate the wafer W from the upper surface of the susceptor 11 to create a space S, a high voltage is applied to the electrode plates 20, N ₂ Gas and the like are supplied to the space S from the heat transfer gas supply hole 27, and the inside of the chamber 10 is exhausted through the rough discharge line. Furthermore, the process gas is introduced into the chamber 10 from the shower head 33 while the chamber 10 is depressurized by the rough discharge line. Thereby, particles adhering to the back surface of the wafer W are discharged. Next, a substrate cleaning method for removing particles adhering to the back surface of the wafer W performed in the plasma processing apparatus 1 will be described.

FIG. 2 is a sequence diagram of a substrate cleaning process performed in the plasma processing apparatus of FIG. 1 . This substrate cleaning process is performed after etching the wafer W.

In FIG. 2, the preconditions for this process are that the wafer W is etched and placed on the susceptor 11, the voltage is not applied to the electrode plate 20 (HV 0), the APC 14 is opened (APC OPEN), and TMP 15 action. That is to say, it is a state in which the chamber 10 is decompressed (vacuumized) by the main discharge line, and the valves V1-V3 are all closed (V1 CLOSE, V2 CLOSE, V3 CLOSE).

First, the (PIN DOWN) push pin 30 housed in the susceptor 11 lifts up (PIN UP) the wafer W away from the susceptor 11. At this time, the height at which the push pins 30 lift the wafer W from the susceptor 11 is not particularly limited, but is preferably 10 to 20 mm. Thereby, a space S is formed between the upper surface of the susceptor 11 and the back surface of the wafer W. As shown in FIG.

Next, the APC 14 is closed (APC CLOSE), and the valve V2 of the exhaust pipe 17 and the valve V3 of the heat transfer gas supply pipe 29 are opened (V2 OPEN, V3 OPEN), and the heat transfer gas supply hole 27 is opened toward the rear surface of the lifted wafer W. The N ₂ gas is ejected into the space S, and the N ₂ gas ejected into the space S is discharged out of the chamber 10 together with the gas remaining in the chamber 10 through the rough discharge pipeline. Thereby, a viscous flow having a large gas viscous force is generated in the space S, flowing from the rear surface of the wafer W toward the outer peripheral portion of the susceptor 11 . At this time, since the viscous flow is likely to occur if the inside of the chamber 10 is above a predetermined pressure, the rough discharge line discharges _N2 gas and the like in the chamber 10 so that the pressure inside the chamber 10 does not fall below the predetermined pressure, For example, 133 Pa (1 torr), it is preferable to maintain the pressure in the chamber 10 within a predetermined pressure range, for example, the range of 1.33×10 ³ to 1.33×10 ⁴ Pa (10 to 100 torr). Thereby, viscous flow can be reliably generated in the space S. The viscous flow entrains particles detached from the rear surface of the wafer W described later, and is discharged from the chamber 10 together with the gas in the chamber 10 .

Next, the DC power supply 22 alternately applies high voltages of different polarities, for example, voltages of +500V and -500V, to the electrode plate 20 (HV+500, HV-500). At this time, due to the application of the high voltage to the electrode plate 20, an electrostatic field is generated in the chamber 10, especially in the space S, and electrostatic stress, for example, Maxwell stress acts on the back surface of the wafer W. Thereby, the adhesive force of the particles adhering to the back surface of the wafer W is weakened, and the particles are detached. The detached particles are expelled from the space S to the outside of the chamber 10 by the above-mentioned viscous flow. The electrostatic stress described above effectively acts on the back surface of the wafer W when the high voltage is applied to the electrode plate 20 and when it is stopped. Here, in the plasma processing apparatus 1 , since the application of high voltage to the electrode plate 20 is repeated, effective electrostatic stress repeatedly acts on the back surface of the wafer W. Thus, particles adhering to the back surface of wafer W can be removed more sufficiently.

The absolute value of the voltage alternately applied to the electrode plates 20 is preferably larger, for example, 500V or more, preferably 2kV or more. Thereby, the electrostatic stress acting on the back surface of the wafer W can be increased, and the particles can be detached reliably.

In addition, when the high voltage of the same polarity is repeatedly applied to the electrode plate 20, the electrode plate 20 is charged (charged), and as a result, the stress of the static electricity acting on the back surface of the wafer W is reduced, and the electrode plate 20 may adhere to the back surface of the wafer W. The particle removal efficiency is reduced. In the plasma processing apparatus 1 , since high voltages of different polarities are alternately applied to the electrode plate 20 , the electrode plate 20 is not charged, and a reduction in removal efficiency of particles adhering to the back surface of the wafer W can be prevented.

Furthermore, as described above, the effective action of the electrostatic stress is related to the frequency of application of the high voltage to the electrode plate 20 , and has little relationship to the application time of the high voltage to the electrode plate 20 . Therefore, the application time of the high voltage to the electrode plate 20 may be, for example, 1 second or less.

During the alternating application of high voltages with different polarities to the electrode plate 20, the valve V1 of the process gas introduction pipe 38 is opened (V1 OPEN), and an inert gas is introduced into the chamber 10 from the shower head 33 instead of the process gas. , for example, _N2 gas. At this time, since the inside of the chamber 10 is depressurized by the rough discharge line, a sharp pressure rise is generated directly under the shower head 33, whereby the introduced N ₂ gas generates a traveling shock wave, and the generated traveling shock wave reaches the height of the lift. The raised wafer W. As a result, impact force is applied to the wafer W, and the particles attached to the back surface of the wafer W are detached. Also at this time, the detached particles are discharged from the space S to the outside of the chamber 10 by the above-mentioned viscous flow.

In addition, in the plasma processing apparatus 1, in order to effectively increase the pressure immediately below the shower head 33 in the chamber 10 when _N gas is introduced, the processing gas introduction pipe 38 is preferably disposed downstream of the valve V1. Orifice structures such as flow control devices (mass flow controllers) or deceleration valves.

Then, in the state where the valve V1 of the processing gas introduction pipe 38 is open (V1 OPEN), high voltages with different polarities to the electrode plate 20 are alternately applied a predetermined number of times, for example, after 4 times, the processing gas introduction pipe 38 is closed. The valve V1 of the exhaust pipe 17 is closed (V1 CLOSE), the APC 14 is opened (APC OPEN), and the valve V2 of the exhaust pipe 17 and the valve V3 of the heat transfer gas supply pipe 29 are closed (V2 CLOSE, V3 CLOSE), and this process ends.

Although the above-mentioned wafer W subjected to the substrate cleaning process is carried out of the chamber 10 through the loading and unloading port 31, and is carried into a transfer chamber, for example, a load lock chamber, since the particles adhering to the back surface of the wafer W are sufficiently removed, the load The locked chamber will not be contaminated by particles.

If the above-mentioned substrate cleaning method is used, since a space S is generated between the susceptor 11 and the wafer W, high voltages with different polarities are alternately applied to the electrode plate 20, so an electrostatic field is generated in the above-mentioned space S and electrostatic stress Acting on the back surface of the wafer W, and further, when the above-mentioned space S is generated and the chamber 10 is depressurized by the rough discharge line, because _N gas is introduced into the chamber 10, a traveling shock wave is generated in the chamber 10, and the generated The traveling shock wave imparts an impact force on the wafer W. Thereby, the particles adhering to the back surface of the wafer W escape to the space S. As shown in FIG. Therefore, since sputtering by plasma ions or chemical reaction by radicals is not required for detachment of particles, wafer W is not damaged.

In addition, when the above-mentioned space S is generated, the _N2 gas is ejected from the heat transfer gas supply hole 27 into the space S, and the _N2 gas ejected into the space S is discharged to the outside of the chamber 10 through the rough discharge line. A viscous flow of _N2 gas is generated in the space S. The detached particles are drawn into the above-mentioned viscous flow and discharged from the space S to the outside of the chamber 10 .

Therefore, the particles adhering to the back surface of the wafer W can be sufficiently removed without damaging the wafer W.

In the above-mentioned plasma processing apparatus 1, although the _N2 gas and the like in the chamber 10 are exhausted from the rough discharge line so that the pressure in the chamber 10 does not fall below a predetermined pressure, it is also possible to reduce the pressure by reducing the rough discharge line instead of the rough discharge line. The opening of the small APC 14 depends on the main discharge line to discharge the _N2 gas in the chamber 10, etc. so that the pressure in the chamber 10 is not lower than the specified pressure, even by means of which a viscous flow can be generated in the space S.

In addition, the present invention is applicable not only to a plasma processing apparatus configured as an etching processing apparatus, but also to other plasma processing apparatuses, for example, a plasma processing apparatus configured as a CVD apparatus or an ashing apparatus.

Next, a plasma processing apparatus as a substrate cleaning apparatus according to a second embodiment of the present invention will be described in detail.

Since the plasma processing apparatus according to the second embodiment of the present invention has basically the same configuration and functions as those of the above-mentioned first embodiment, the description of the redundant configuration and functions will be omitted, and the different configurations and functions will be described below. instruction of.

Although in the plasma processing apparatus as the substrate cleaning apparatus according to the second embodiment, similar to the first embodiment, when the wafer W is separated from the upper surface of the susceptor 11 by the push pin 40 described later and the space S is generated, the The electrostatic field and electrostatic stress act on the back surface of the wafer W, but the electrostatic field is not caused by the application of a high voltage to the electrode plate 20, but is caused by the application of a high voltage to the wafer W by the push pin 40. One embodiment is different.

3 is a diagram showing a schematic configuration of a push pin in a plasma processing apparatus as a substrate cleaning apparatus according to a second embodiment.

In FIG. 3 , the push pin 40 is a rod-shaped body made of a conductor, one end contacting the back surface of the wafer W is formed in a hemispherical shape, and the other end is electrically connected to a DC power supply 41 . In addition, the surface of the push pin 40 is preferably covered with a dielectric or the like in order to prevent discharge from the surface, but the surface at one end of the hemispherical shape exposes a conductor to apply a high voltage to the wafer W. The push pin 40 is converted into a linear motion by a ball screw or the like from a rotational motion of a motor (not shown), and moves vertically in the figure.

In addition, a plurality of ejector pins 40 are arranged on the upper surface of the susceptor 11 at a portion where the wafer W is adsorbed. Further, the ejector pins 40 protrude from the upper surface of the susceptor 11 to lift the wafer W away from the susceptor 11 upward. At this time, a space S is formed between the upper surface of the susceptor 11 and the wafer W as in the first embodiment.

In the plasma processing apparatus as the substrate cleaning apparatus according to the second embodiment, after the etching process is performed on the wafer W, when the wafer W is separated from the upper surface of the susceptor 11 by the push pins 40 to create a space S, a high voltage is applied via the push pins. 40 is applied to the wafer W from the DC power supply 41, N ₂ gas is supplied to the space S from the heat transfer gas supply hole 27, and the inside of the chamber 10 is exhausted through the rough discharge line. Furthermore, the process gas is introduced into the chamber 10 from the shower head 33 while the chamber 10 is depressurized by the rough discharge line.

Further, in the substrate cleaning method carried out in the plasma processing apparatus as the substrate cleaning apparatus according to the second embodiment, although high voltages of different polarities are alternately applied to the electrode plate 20 via the push pin 40, the polarity Different from the first embodiment in that different high voltages are alternately applied to the wafer W, an electrostatic field is generated in the space S, the electrostatic stress acts on the back surface of the wafer W, and the adhesion of the particles attached to the back surface of the wafer W Weakening, the detachment of the particles is the same as that of the first embodiment.

In addition, the high voltage applied to the wafer W via the push pins 40 is, for example, 500 V or more, preferably 2 kV or more, and the application time of the high voltage may be 1 second or less, which is the same as in the first embodiment.

If the above-mentioned substrate cleaning method is used, when a space S is generated between the susceptor 11 and the wafer W, high voltages with different polarities are alternately applied to the wafer W via the push pin 40, so an electrostatic field is generated in the space S. And electrostatic stress acts on the back surface of the wafer W, and then, when the above-mentioned space S is generated and the chamber 10 is depressurized by the rough discharge line, because _N gas is introduced into the chamber 10, a traveling shock wave is generated in the chamber 10 , the generated traveling shock wave exerts an impact force on the wafer W. Thereby, the particles adhering to the back surface of the wafer W escape to the space S. As shown in FIG. Therefore, since sputtering by plasma ions or chemical reaction by radicals is not required for detachment of particles, wafer W is not damaged.

In addition, when the above-mentioned space S is generated, the _N2 gas is ejected from the heat transfer gas supply hole 27 into the space S, and the _N2 gas ejected into the space S is discharged to the outside of the chamber 10 through the rough discharge line. A viscous flow of _N2 gas is generated in the space S. The detached particles are drawn into the above-mentioned viscous flow and discharged from the space S to the outside of the chamber 10 .

Therefore, the particles adhering to the back surface of the wafer W can be sufficiently removed without damaging the wafer W.

Next, a substrate cleaning apparatus according to a third embodiment of the present invention will be described in detail.

The substrate processing apparatus according to the third embodiment differs from the above-described first and second embodiments in that only the back surface of the wafer W is cleaned without performing plasma processing on the wafer W.

4 is a cross-sectional view showing a schematic configuration of a substrate cleaning apparatus according to a third embodiment of the present invention.

In FIG. 4 , a substrate cleaning device 42 has a box-shaped chamber 43 made of metal such as aluminum or stainless steel, and a cylindrical table 44 on which a wafer W is placed is disposed in the chamber 43 .

Between the side wall of the chamber 43 and the table 44 is formed an exhaust passage 65 functioning as a flow passage for discharging the gas above the table 44 to the outside of the chamber 43 . This exhaust path 65 is connected to the rough exhaust line. This rough discharge line communicates the exhaust passage 65 with the DP 46 as an exhaust pump, and is equipped with an exhaust pipe 45 having a diameter of, for example, 25 mm and a valve V5 disposed in the middle of the exhaust pipe 45. This valve V5 can isolate the exhaust passage 65 and the DP 46. The rough discharge line exhausts the gas in the chamber 43 by DP 46.

A disk-shaped electrode plate 47 composed of a conductive film for attracting wafer W by electrostatic attraction is disposed above the table 44 , and a DC power supply 48 is electrically connected to the electrode plate 47 . The wafer W is attracted and held on the upper surface of the table 44 by the Coulomb force generated by the DC voltage applied from the DC power supply 48 to the electrode plate 47 .

A plurality of gas supply holes 49 are formed on the upper surface of the stage 44 where the wafer W is adsorbed. These gas supply holes 49 communicate with a gas supply pipe 64 having a valve V6 via a gas supply line 50 arranged inside the workbench 44, and the gas from a first gas supply part (not shown) connected to the gas supply pipe 64, For example, N ₂ gas is supplied to the gap between the upper surface of the stage 44 and the back surface of the wafer W. Furthermore, the valve V6 can isolate the gas supply hole 49 from the first gas supply part.

In addition, a plurality of pins 51 protruding from the upper surface of the table 44 are arranged on the portion where the wafer W is adsorbed on the upper surface of the table 44 . The pins 51 lift the wafer W carried into the chamber 43 to leave the stage 44 . At this time, a space S is formed between the upper surface of the stage 44 and the back surface of the wafer W. As shown in FIG. These pins 51 can also move up and down in the figure like the push pin 30 .

A gate valve 53 for opening and closing the loading and unloading port 52 of the wafer W is attached to the side wall of the chamber 43 . In addition, a gas introduction pipe 54 for introducing gas such as N ₂ gas into the chamber 43 from a second gas supply unit (not shown) is connected to the ceiling of the chamber 43 . A valve V4 is disposed in the middle of the gas introduction pipe 54 . This valve V4 can isolate the inside of the chamber 43 from the second gas supply unit.

This substrate cleaning apparatus 42 is arranged, for example, in a parallel type substrate processing system, and removes particles adhering to the back surface of the wafer W subjected to plasma processing by a plasma processing apparatus 56 described later provided in the substrate processing system.

FIG. 5 is a diagram showing a schematic configuration of a substrate processing system disposed in the substrate processing apparatus of FIG. 4 .

In FIG. 5 , a substrate processing system 55 is provided with a plasma processing apparatus 56 for etching a wafer W and a load equipped with a ring-shaped single pick-up transfer arm 57 for transferring the wafer W to the plasma processing apparatus 56. A processing station 59 constituted by a lock chamber 58, a load port 60 for accommodating a loading box storing a batch of wafers W, an orientation device 61 for pre-aligning wafers W, the above-mentioned substrate cleaning device 42, and a rectangular common transfer path are arranged. The load unit 63 of the articulated double-arm type conveying arm 62 is provided. Although the processing station 59, the load port 60, the orientation device 61, and the substrate cleaning device 42 are detachably connected to the load unit 63, the substrate cleaning device 42 is disposed at one end related to the longitudinal direction of the load unit 63, and passes through the load unit 63. Opposite to the azimuth 61.

In this substrate processing system 55 , the wafer W subjected to plasma processing in the plasma processing apparatus 56 is carried into the substrate cleaning apparatus 42 by the transfer arm 57 in the load lock chamber 58 and the transfer arm 62 in the load unit 63 . The substrate cleaning device 42 performs a substrate cleaning method described later to remove particles adhering to the back surface of the wafer W.

Next, a substrate cleaning method performed in the substrate cleaning device 42 will be described.

The prerequisites for this substrate cleaning method are that the wafer W is etched and placed on the table 44 , no voltage is applied to the electrode plate 47 , and all valves V4 to V6 are closed.

First, the wafer W loaded into the chamber 43 is placed on the pins 51 protruding from the upper surface of the table 44 . At this time, the height at which the pins 51 lift the wafer W from the table 44 may be 10 to 20 mm as in the first embodiment. Thereby, a space S is formed between the upper surface of the stage 44 and the back surface of the wafer W. As shown in FIG.

Then, the gate valve 53 is closed, and the valve V5 of the exhaust pipe 45 and the valve V6 of the gas supply pipe 64 are opened, and the gas supply hole 49 ejects _N gas to the space S toward the back surface of the lifted wafer W, and the rough discharge line The N ₂ gas injected into the space S is exhausted to the outside of the chamber 43 . Thereby, in the space S, a viscous flow of N ₂ gas flowing from the back surface of the wafer W toward the outer peripheral portion of the stage 44 is generated. At this time, as in the first embodiment, the N ₂ gas in the chamber 43 is exhausted from the rough discharge line so that the pressure in the chamber 43 does not fall below a predetermined pressure. The viscous flow entrains particles detached from the back surface of the wafer W described later and is discharged from the chamber 43 .

Next, the DC power supply 48 alternately applies high voltages with different polarities to the electrode plates 47 . At this time, an electrostatic field is generated in the space S, and electrostatic stress acts on the back surface of the wafer W, so that the adhesion of the particles adhering to the back surface of the wafer W is weakened, and the particles detach, as in the first embodiment. Then, the detached particles are discharged from the space S to the outside of the chamber 43 by the above-mentioned viscous flow.

Furthermore, the high voltage applied to the electrode plate 47 is, for example, 500V or higher, preferably 2kV or higher. And the case where the application time of the high voltage may be, for example, 1 second or less is the same as that of the first embodiment.

During the above-described alternating application of high voltages of different polarities to the wafer W, the valve V4 of the gas introduction pipe 54 is opened, and N ₂ gas is introduced into the chamber 43 from the gas introduction pipe 54 . At this time, because the inside of the chamber 43 is decompressed by the rough discharge line, a sharp pressure rise occurs immediately below the top of the chamber 43, and the introduced _N gas generates a traveling shock wave, and the impact force is caused by the generated traveling shock wave. On the other hand, when it is applied to the wafer W, the particles adhering to the back surface of the wafer W are detached, which is the same as that of the first embodiment. Also at this time, the detached particles are discharged from the space S to the outside of the chamber 43 by the above-mentioned viscous flow. In addition, in the substrate cleaning apparatus 42 , as in the first embodiment, it is preferable to arrange an orifice structure in the gas introduction pipe 54 downstream of the valve V4 .

Then, after the valve V4 of the gas introduction pipe 54 is opened, high voltages with different polarities are alternately applied to the wafer W a predetermined number of times, the valve V4 of the gas introduction pipe 54, the valve V5 of the exhaust pipe 45, and The valve V6 of the gas supply pipe 64 is closed, and this process ends. Although the above-mentioned wafer W subjected to the substrate cleaning process is carried out of the chamber 43 through the loading and unloading port 52, and loaded into the load unit 63 or the load port 60, since the particles adhering to the back surface of the wafer W are sufficiently removed, the load unit 63 Or the inside of the load port 60 will not be polluted by particles.

If the above-mentioned substrate cleaning method is used, since a space S is generated between the workbench 44 and the wafer W, high voltages with different polarities are alternately applied to the wafer W, so an electrostatic field is generated in the above-mentioned space S and the stress of the static electricity acts. On the back side of the wafer W, further, when the above-mentioned space S is generated and the inside of the chamber 43 is depressurized by the rough discharge line, because _N gas is introduced into the chamber 43, a traveling shock wave is generated in the chamber 43, and the generated traveling shock wave The shock wave applies an impact force to the wafer W. As shown in FIG. Thereby, the particles adhering to the back surface of the wafer W escape to the space S. As shown in FIG. Therefore, since plasma is not required for detachment of particles, wafer W is not damaged.

In addition, since the _N gas is ejected from the gas supply hole 49 into the space S when the above-mentioned space S is generated, and the _N gas ejected into the space S is discharged to the outside of the chamber 43 through the rough discharge line, the space S A viscous flow of _N2 gas is produced in the The detached particles are drawn into the above-mentioned viscous flow and discharged from the space S to the outside of the chamber 43 .

Therefore, the particles adhering to the back surface of the wafer W can be sufficiently removed without damaging the wafer W.

In the substrate cleaning device 42 described above, although the substrate cleaning device 42 has its own DP 46 , the substrate cleaning device 42 and the plasma processing device 56 may share a DP, thereby simplifying the configuration of the substrate processing system 55 .

Although in the above-mentioned embodiment, the occasion where the plasma processing apparatus functions as a substrate cleaning apparatus or the occasion where a dedicated substrate cleaning apparatus is provided has been described, other apparatuses constituting the substrate processing system may also be used as the substrate cleaning apparatus according to the present invention. The substrate cleaning device functions.

For example, in the case where a load lock chamber functions as a substrate processing apparatus according to the present invention, the load lock chamber is equipped with a transfer arm, an exhaust device for exhausting the load lock chamber, and a gas introduction device for introducing gas into the load lock chamber. The device, the transfer arm preferably includes a pin protruding from the wafer placement surface, an electrode for generating an electrostatic field between the wafer W and the wafer placement surface, and a gas injection device for ejecting gas toward the back surface. In the load lock chamber, when the wafer W is lifted from the wafer mounting surface by pins to create a space S, a high voltage is applied to the electrodes, and the gas is sprayed to the back of the wafer W, and the load lock chamber is exhausted by an exhaust device. Furthermore, while the load lock chamber is decompressed by the exhaust device, gas is introduced into the load lock chamber from the gas introduction device.

Example

Next, examples of the present invention will be specifically described.

The following examples are carried out in the plasma processing apparatus 1 described above.

First, a wafer W on which a large amount of particles adheres to the back surface is prepared, and the wafer W is placed on the ejector pins 30 protruding from the susceptor 11 in the chamber 10 .

Then, after the chamber 10 is depressurized by the main discharge line, the APC 14 is closed, and the valve V2 of the exhaust pipe 17 and the valve V3 of the heat transfer gas supply pipe 29 are opened to stably exhaust the chamber 10. While the N ₂ gas is sprayed from the heat transfer gas supply hole 27 toward the back surface of the wafer W. Thereby, a viscous flow is generated in the space S while keeping the inside of the chamber 10 at 6.65×10 ³ Pa (50 torr) or higher.

Next, the valve V1 was opened to introduce N ₂ gas into the chamber 10 at a flow rate of 7.0×10 ⁴ SCCM. While the valve V1 was open, the alternating application of voltages of +2 kV and -2 kV to the electrode plate 20 was repeated six times, and then the valve V1 was closed. Furthermore, the valve V1 was opened again to introduce _N2 gas into the chamber 10 at a flow rate of 7.0×10 ⁴ SCCM, and the alternating application of +2kV and -2kV voltages to the electrode plate 20 was repeated 5 times while the valve V1 was open. Then, valve V1 is closed. At this time, the space S is irradiated with laser light, and the stray light caused by the particles is observed by imaging with a CCD camera. The state of the captured stray light is shown in FIG. 6 .

FIG. 6( a ) is a diagram schematically showing the state of the space S when alternating voltages of +2 kV and -2 kV are repeatedly applied to the electrode plate 20 while the valve V1 is open. Here, a large number of particles are detached from the back surface of the wafer W by the traveling shock wave generated by the introduced _N gas and the electrostatic stress generated by the alternating application of voltage, and it is observed that the detached particles form a group L.

FIG. 6( b ) is a diagram schematically showing the state of the space S after several seconds have elapsed from FIG. 6( a ). Here, in the space S, it is observed that a group L of particles is discharged from the space S by the viscous flow flowing from the back surface of the wafer W toward the outer peripheral portion of the susceptor 11 .

FIG. 6( c ) is a diagram schematically showing the state of the space S after several seconds have elapsed from FIG. 6( b ). Here, a situation in which a population L of particles is completely excluded from the space S is observed.

A graph summarizing these observations is shown in FIG. 7 .

In FIG. 7, the horizontal axis represents time, and the vertical axis represents the number of particles, voltage value and pressure value. In addition, _VE represents the voltage applied to the electrode plate 20, and V _W represents the voltage induced on the wafer _W due to VE. P denotes the pressure inside the chamber 10 . Furthermore, each point plotted in the graph represents the number of particles observed at each observation time. In addition, the portion where the value of P becomes constant is the portion where the pressure in the chamber 10 exceeds the measurable range.

It can be seen from FIG. 7 that after the valve V1 is opened and a large amount of _N2 gas is introduced into the chamber 10, the particles are largely detached from the back surface of the wafer W due to the generated traveling shock waves, and then the particles pass through the electrode plate 20 repeatedly. Further detachment by alternating application of voltage. It can be seen from this that the particles adhering to the back surface of the wafer W can be sufficiently detached by repeating the introduction of a large amount of N ₂ gas into the chamber 10 and the above-mentioned alternating application of the voltage. Furthermore, it can be seen that the number of detached particles decreases in the repetition of the second large amount of _N2 gas introduction into the chamber 10 and the above-mentioned alternating application of the voltage, so by performing a large amount _{of N2} gas into the chamber 10 once, The repetition of the introduction and the alternating application of the above-mentioned voltage can effectively detach the particles.

In addition, although the particles discharged from the chamber 10 through the rough discharge line were observed by the particle monitor using the laser light scattering method provided in the middle of the rough discharge line, the same observation results as in FIG. 7 were obtained. From this it can be seen that the viscous flow efficiently expels dislodged particles from within the chamber 10 .

Claims (14)

1. a base plate cleaning device is characterized in that, has

Accommodate the reception room of substrate;

Be disposed in this reception room the mounting table of the described substrate of mounting;

Be disposed at this mounting table, make described substrate be adsorbed in the electrode of described mounting table when applying voltage;

To carrying out the exhaust apparatus of exhaust in the described reception room;

This mounting table and described substrate are left and between described mounting table and described substrate, produce the separating device in space; With

Gas is supplied to the gas supply device in described space,

When producing described space, voltage puts on described electrode, and described gas supply device supplies to described space to gas, and described exhaust apparatus carries out exhaust to described reception room.

2. base plate cleaning device as claimed in claim 1 is characterized in that,

Also have and in described reception room, be depressurized and when producing described space, gas is imported gas introduction part in the described reception room.

3. base plate cleaning device as claimed in claim 1 or 2 is characterized in that,

Voltage puts on described electrode discontinuously.

4. base plate cleaning device as claimed in claim 3 is characterized in that,

The voltage that polarity is different alternatively puts on described electrode.

5. base plate cleaning device as claimed in claim 4 is characterized in that,

The absolute value of described voltage is more than the 500V.

6. base plate cleaning device as claimed in claim 5 is characterized in that,

The absolute value of described voltage is more than the 2kV.

7. as each described base plate cleaning device in the claim 1 to 6, it is characterized in that,

Described exhaust apparatus remains in the pressure in the described reception room when producing described space

8. base plate cleaning device as claimed in claim 7 is characterized in that,

Described exhaust apparatus remains in 1.33 * 10 to the pressure in the described reception room when producing described space ³～1.33 * 10 ⁴In the scope of Pa.

9. a base plate cleaning device is characterized in that, has

Accommodate the reception room of substrate;

Be disposed in this reception room the mounting table of the described substrate of mounting;

To carrying out the exhaust apparatus of exhaust in the described reception room;

This mounting table and described substrate are left and between described mounting table and described substrate, produce the space, and voltage is put on the separating device of described substrate with described substrate contacts;

Gas is supplied to the gas supply device in described space; With

In described reception room, import the gas introduction part of gas,

When producing described space, voltage puts on described substrate, described gas supply device supplies to described space to gas, described exhaust apparatus carries out exhaust to described reception room, and then, in described reception room, be depressurized and when producing described space, described gas introduction part imports gas in the described reception room.

10. a substrate-cleaning method is removed the foreign matter at the back side that is attached to substrate, it is characterized in that this method comprises

Substrate is contained in the step of accommodating of reception room;

The mounting step of described substrate-placing in the mounting table that is disposed at described reception room;

Described mounting table and described substrate are left so that between described mounting table and described substrate, produce the step of leaving in space;

When producing described space, the voltage that voltage is put on the electrode that is disposed at described mounting table applies step;

When producing described space, gas is supplied to the gas supplying step in described space; With

When producing described space, to carrying out the steps of exhausting of exhaust in the described reception room.

11. substrate-cleaning method as claimed in claim 10 is characterized in that,

Also be included in when being depressurized and producing described space in the described reception room, the gas that gas is imported in the described reception room imports step.

12. as claim 10 or 11 described substrate-cleaning methods, it is characterized in that,

Apply in the step at described voltage, voltage is put on described electrode discontinuously.

13. substrate-cleaning method as claimed in claim 12 is characterized in that,

Apply in the step at described voltage, the voltages different polarity alternatively put on described electrode.

14. a substrate-cleaning method is removed the foreign matter at the back side that is attached to substrate, it is characterized in that this method comprises:

Substrate is contained in the step of accommodating of reception room;

The mounting step of described substrate-placing in the mounting table that is disposed at described reception room;

Described mounting table and described substrate are left so that between described mounting table and described substrate, produce the step of leaving in space;

When producing described space, the voltage that voltage is put on described substrate applies step;

When producing described space, gas is supplied to the gas supplying step in described space;

When producing described space, to carrying out the steps of exhausting of exhaust in the described reception room; With

In described reception room, be depressurized and when producing described space, the gas that gas is imported in the described reception room imports step.

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