TWI426352B - Atmosphere exchange method - Google Patents

Description

Atmospheric exchange method

The invention relates to an atmospheric exchange method.

A conventional load lock chamber is introduced into a processing chamber for processing the substrate in a vacuum atmosphere by a substrate stacker placed in the atmosphere, or a processed substrate is output from the processing chamber to the substrate stacker. . As used herein, the processing chamber means an EUV (extreme ultraviolet) exposure apparatus and a plasma processing apparatus.

The load lock chamber has the function of exchanging the atmosphere in the atmosphere between the atmosphere and the vacuum environment. More specifically, the substrate is introduced into the processing chamber (in the exhaust process), the load lock chamber exchanges the atmosphere from the atmosphere to the vacuum environment, and the substrate is output to the substrate stack In the hopper (in the gas supply process), the atmosphere is exchanged from the vacuum environment to the atmospheric environment. The load lock chamber is coupled to the process chamber via a gate valve and includes a substrate transport mechanism.

However, during the supply and exhaust times, particles from the gate valve and the substrate transport member vortex and a mechanism is needed to reduce or prevent adhesion of particles to the substrate. A proposed method utilizes the thermophoretic force to reduce the adhesion of particles to the substrate. As disclosed in Japanese Patent No. 2,886,521, the method heats the jig of the substrate until a temperature higher than the peripheral temperature, and collects the particles via a low temperature particle collector maintained at a temperature lower than the peripheral temperature.

According to the principle of the thermophoretic force, the particles are given the kinetic energy by the gas molecules in a temperature gradient in the gas surrounding the particles, and the kinetic energy of the gas molecules from the high temperature side is higher than that from The kinetic energy of the gas molecules on the low temperature side, and the particles are moved by the object on the high temperature side to the low temperature side. By the equations of the thermophoresis coefficient described in Kikuo Okuyama, Hiroaki Masuda, and Seiji Morooka, published in Ohmsha in May 1992, "New System Chemicals, Fine Particle Engineering Technology", pages 106-107, by the following equation With thermal swimming force Fx.

Equation 1 assumes that the particles are spherical and that the system is the ideal gas. Dp is a particle diameter. T is a gas temperature. μ is a viscosity coefficient. ρ is a gas density. Kn is a Knudsen number and 2λ/Dp. λ is an average free path and η/{0.499P(8M/pRT) ^1/2 }. M series molecular weight. R system gas constant. K series k / kP. k is the thermal conductivity of the gas caused only by the parallel kinetic energy. Kp is the thermal conductivity of the particles. The Cs is 1.17. Ct is 2.18. Cm is 1.14. ΔT/Δx is a temperature gradient.

The size of the load lock chamber is limited by the size of the gate opening (W360 mm x H80 mm) as determined by the uniform standards in the semiconductor art, and cannot be made as small as the outer shape of the substrate. Therefore, close to the substrate clip The thermophoretic force inevitably depends on the shape of the load lock chamber and cannot be maximized.

The present invention is directed to an atmosphere exchange method that reduces the adhesion of particles to the substrate in a vacuum chamber. As used in the specific embodiments below, the "vacuum chamber" means a device that requires a reduced pressure state, in principle like an exposure chamber in an EUV exposure apparatus, and means that the reduced pressure state is temporarily maintained. The device is like a load lock chamber of a substrate transport mechanism.

An atmosphere exchange method according to an aspect of the present invention is a method for exchanging the atmosphere of a vacuum chamber of a processing apparatus, the processing apparatus being configured to process a substrate under a vacuum environment. The method includes the steps of: holding the substrate using a holding unit provided in the vacuum chamber; and exchanging the atmosphere of the vacuum chamber through exhaust or gas supply, wherein the exchange step maintains the pressure at 10 Pa (Pa) and 10,000 Pa In the range between 10 seconds and 600 seconds, the temperature of the dust collecting unit provided in the vacuum chamber is controlled to be lower than the temperature of the substrate.

Further features of the present invention will become apparent from the following description of exemplary embodiments (refer to the accompanying drawings).

Referring now to the drawings, a processing apparatus in accordance with a particular embodiment of the invention will be described. This embodiment uses an EUV exposure device as A processing apparatus that processes a substrate under a vacuum environment, but the invention is not limited to the processing apparatus.

First specific embodiment

Fig. 1 is a schematic cross-sectional view of an exposure apparatus according to the first embodiment. In Fig. 1, 1 indicates an excitation laser, and a YAG solid-state laser or the like is used. The excitation laser 1 irradiates the laser beam to a radiation point of a light source and radiates the light for plasma excitation of the source material of the light source. The radiation point is made by vaporizing, liquefying, or spraying a light source material. 2 indicates one of the light source radiating members of the exposure light source, and maintains a vacuum inside thereof. 2A indicates a radiation point of the exposure light source. 2B designates a light source lens that is disposed to surround the hemispherical lens of the radiation point 2A so as to deflect, condense, and reflect the entire spherical light from the radiation point 2A toward the radiation direction. A nozzle (not shown) is used to radiate liquefied ruthenium, liquefied ruthenium spray, or helium gas as radiation atoms to the radiation spot 2A, and the light from the excitation laser 1 is irradiated to the radiation spot 2A.

3 indicates an exposure chamber connected to the light source radiating member 2. The exposure chamber 3 is maintained under a vacuum environment or at a reduced pressure by an exhaust unit (vacuum pump) 4A. The exposure chamber 3 is a vacuum chamber that maintains a vacuum pressure suitable for the EUV exposure. 5 indicates an illumination optical system for introducing and shaping the exposure light by the light source radiating member 2, including lenses 5A to 5D, and homogenizing and shaping the exposure light. 6 indicates a reticle stage, and a reticle (original) 6A is electrostatically held on a movable member of the reticle stage 6 as a reflective original having an exposure pattern.

7 indicates a projection optical system that continuously projects a reduced image of the exposure pattern reflected from the mask 6A onto a wafer 8A in a predetermined reduction ratio by a sequence of lenses 7A to 7E to reflect An exposure pattern reflected by the mask 6A. 8 designating a wafer table that positions the wafer 8A as a Si substrate to an exposure position, the mask pattern being exposed to the exposure position to control the position of the wafer table in a six-axis direction The six-axis direction includes an XYZ-axis direction, an oblique direction surrounding the X-axis and the Y-axis, and a rotation direction surrounding the Z-axis.

9 indicates a support member that supports the reticle table 6 on the floor. 10 denotes a support member that supports the projection optical system 7 on the floor. 11 indicates a support member that supports the wafer table 8 on the floor. A control unit (not shown) measures and continuously maintains the relative position between the mask table 6 and the projection optical system 7 and the relative position between the projection optical system 7 and the wafer table 8. Each of the support members 9 to 11 has a mount (not shown) that isolates the shock from the floor.

16 indicates a wafer stocker that temporarily stores a wafer 8A on the inside of the apparatus, which has been carried by the wafer carrier unit 17A on the atmospheric air side. The wafer stocker 16 stores a plurality of wafers. The wafer 8A to be exposed is sorted and transported by the wafer stocker 16 to the holding unit 18, and the holding unit is mounted to the vacuum chamber or the load lock chamber 26. 19 indicates a shield plate (dust collection unit) ), which surrounds the perimeter of the wafer. 20D is a gate valve that connects the space of the wafer stocker 16 to the load lock chamber 26 and opens and closes when the load lock chamber 26 is in the atmospheric pressure state close. 20E is also a gate valve that connects the load lock chamber 26 to the exposure chamber 3 and opens and closes when the load lock chamber 26 is in the vacuum state. The wafer carrier unit 17B, which can transport a wafer in the vacuum state, carries the wafer from the holding unit 18 to a wafer mechanical pre-aligned temperature controller placed in the exposure chamber (processing chamber) ( Not shown). The wafer mechanical pre-alignment temperature controller provides a preliminary feed adjustment in the direction of rotation of the wafer and controls the wafer temperature to a reference temperature of the exposure device. The wafer carrier unit 17B feeds the wafer 8A to the wafer table 8, which is aligned and temperature controlled by the wafer mechanically pre-aligned with the temperature controller.

The output program of the wafer 8A from the exposure chamber 3 is opposite to the loading procedure.

27 indicates a SMIF pod as a small environment for transporting reticle cassettes in the facility's manufacturing facility. 31 indicates a reticle cassette held in the SMIF container. Once the SMIF indicator 34 opens and closes the SMIF container, the reticle cassette 31 is introduced into the exposure apparatus such that the reticle carrier unit 14A is ready to carry the reticle cassette 31. 24 indicates a load interlock A chamber for exchanging the atmosphere for the photomask cassette 31 from the air atmosphere to the vacuum atmosphere, and includes a cassette holding unit 28.

20A designates a gate valve that connects the space of the reticle cassette 31 to the load lock chamber 24 and opens and closes when the load lock chamber 24 is in the atmospheric pressure state. It is a gate opening/closing mechanism, and the reticle 6A is guided by the SMIF indicator 34 to the holding unit of the load lock chamber 24. 20B also indicates a gate valve, which is the load lock chamber 24 Open and close in this vacuum state. 20C also indicates a gate valve that opens and closes when the reticle 6A is introduced into the exposure chamber 3.

12 denotes a reticle stocker that temporarily stores a reticle 6A carried by the outside of the apparatus to the inside of the apparatus, and the reticle 6A is placed in the reticle cassette 31. The reticle stacker 12 stores reticle 6A having different patterns and different exposure conditions on a plurality of stages.

14A designates a reticle carrier unit that carries the reticle cassette 31 to the reticle stacker 12 by the load lock chamber 24. The reticle carrier unit 14B is disposed in a reticle carrier chamber 13. A reticle is selected by the reticle stacker 12, and the reticle cassette 31 is transported to a lid opening mechanism 13A. The cover opening mechanism divides the reticle into a top cover and a lower plate. The mask carrier unit 14B transports the cassette lower plate that has been separated by the cover opening mechanism 13A to a mask alignment range display 15 provided at the end of the mask table 6. Thereby, its continuous movement is aligned with the alignment mark 15A on the outer casing of the projection optical system 7 in the XYZ axis rotation direction on the reticle 6A.

The aligned mask 6A is directly clamped to the mask table 6 by the lower plate. At least one of the rise of the cassette support member or the lowering of the mask table is performed to reduce the distance between the click support member of an alignment member and the mask table 6. At the same time, the inclination between the mask 6A and the mask table 6 is adjusted. After the reticle 6A is transferred to the reticle stage 6, an empty lower plate is returned to the cover opening mechanism 13A by the reticle carrier unit 14B, and after the cover is closed, It is stored in the reticle stacker 12.

2 is a schematic cross-sectional view of the load lock chamber 26 in which a drive unit 21 is moved in the lower direction as a shield plate 19 of the dust collection unit, and the shield plate 19 covers the surface of the wafer 8A. After the temperature control units 22A and 22B control the surface temperature of the shield plate 19 facing the wafer 8A, the driving unit 21 has a function of moving the holding unit 18 and one of the shielding plates 19 close to each other.

Since a narrow space having a distance of 0.5 cm or less can be formed between the surface of the wafer and the shielding plate 19 by moving the shielding plate 19, a temperature gradient of a space close to the surface of the wafer can be made. The temperature gradient is larger than that of the conventional vacuum chamber.

The load lock chamber 26 is separated from the exposure chamber 3 by the gate valve 20E, and the pressure detecting unit 32 detects that the inside of the load lock chamber becomes a vacuum. The gate valve 20E is opened, and the wafer 8A is introduced into or output from the exposure chamber 3. The exhaust unit 4B exhausts or depressurizes the internal space of the load lock chamber 26, and the air supply unit 29 supplies the air to the internal space or compresses the internal space. As such, the load lock chamber 26 exchanges the atmosphere of the vacuum environment and the interior space between the atmospheres.

A flow variable valve 33A is provided to adjust the flow rate of the exhaust gas to the tube 23 between the exhaust unit 4B and the exhaust opening of the load lock chamber 26 and the supply air flow rate. The gas supply unit 29 and the tube 23 between the gas supply openings of the load lock chamber 26 are provided with a flow variable valve 33B for adjusting the exhaust gas flow rate and the gas supply flow rate. A pressure detecting unit 32 and a control unit 30 that controls the exhaust/air supply unit can arbitrarily adjust the tube 23 The gas flow in the middle.

The supply air and the exhaust gas are repeated whenever the pre- or post-process wafer 8A is fed and fed out of the load lock chamber 26. Thereby, particles, such as fine fluorine particles generated by the gate valve in the load lock chamber 26 or fine silver-plated particles generated by the wafer transport mechanism, are likely to be in the exhaust or gas supply process. Vortex, and adhere to the wafer 8A. It is so important to reduce the particles that will adhere to the wafer 8A during the venting or gas supply process of the load lock chamber 26.

The holding unit 18 holding the wafer 8A controls the temperature of all members including a support pin 18A to a first temperature (23 degrees Celsius) via the first temperature control unit 22A. This temperature is as high as the temperature of the wafer 8A carried by the holding unit 18. This embodiment circulates the heat medium in the holding unit 18 and uniformly controls the temperature of the entire surface of the holding unit 18. The temperature of the surface facing the surface of the wafer for protecting the wafer surface from the shield 19 of the particles is controlled to the second temperature (13 degrees Celsius) by the second temperature control unit 22B. The second temperature of the surface of the shield plate 19 is lower than the first temperature by 10 degrees Celsius. Thus, the temperature control units 22A and 22B can control the temperature of the surface of the shield plate 19 facing the wafer 8A to be lower than the temperature of the wafer 8A. Thereby, the shield plate 19 operates as a dust collecting unit having a dust collecting member.

Figure 3 is a graph of the gravitational force and the thermophoretic force affecting the fine fluoroparticles when the temperature gradient is 10 [absolute temperature/cm]. The ordinate axis indicates a force [m/sq.sec.) and the abscissa axis indicates the pressure [Pa] of the load lock chamber 26. The thermophoretic curve is obtained by weighting equation 1, and The difference between the gas temperature and the solid temperature is calculated. It is understood from Fig. 3 that under the pressure range between 10 Pa and 10,000 Pa, the force affecting the fine particles becomes the maximum. The pressure of the load lock chamber 26 is controlled within this pressure range.

This embodiment controls the temperature and position of the shield 19 such that the temperature gradient of the space can be 10 [absolute temperature/cm] and further control the pressure of the load lock chamber 26.

Figure 4 is a graph showing the velocity of fine fluoroparticles having a diameter between 0.1 and 1.5 microns which are brought close to the wafer 8A in the load lock chamber 26. The ordinate axis indicates the speed of the fine particles [m/s], and the abscissa axis indicates the pressure [Pa] of the load lock chamber 26. This speed is positive in the direction of gravity. The velocity V ₁ of fine particles floating near the surface of the wafer is illustrated by a solid line. The velocity V ₂ of fine particles floating near the surface of the wafer is illustrated by an alternating length and short dashed line. The velocity of fine particles floating close to the surface is given as follows: Equation 2v ₁ = (average deposition rate) + (hot swimming velocity) v ₂ = (average deposition rate) - (hot swimming speed)

This hot swimming speed is given as follows:

Equation 3V _th =-K _th vΔT/T

The thermophoretic velocity coefficient K _th is given as follows:

ν is a moving viscosity. The alpha system is a specific heat ratio and is given a heat transfer ratio such as a gas divided by a heat transfer ratio of a particle. The average deposition rate to the wafer 8A in the laminar flow field is given as follows.

v _n =0.739(D/L)(u ₀ L/v) ^1/2 S _c ^1/3 +v _g

D is a diffusion coefficient and is given by C _c kT/(3pμ D _p ). L system wafer diameter. u ₀ is the average flow rate of the gas stream sufficiently far from the wafer 8A. The S _c is a Schmidt number and is given by ν/D. k is a factor of Boltzmann. v _g is the gravity deposition rate of D _p ² ρ _p gC _c /(18μ). ρ _p is the density of fine particles. g is the gravitational acceleration. C _c is a correction factor of Cunnningham and is given as 1+K _n [1.25+0.4exp(-1.1/K _n )].

Equations 2 through 4 are disclosed in the May 2000 version of Takeshi Hattori, Science and Engineering Center Press, "New Cleaning Techniques for Wafer Surfaces," pages 72-74.

Figure 5 is a flow diagram of a wafer process in accordance with a first embodiment. Figure 6A is a graph showing the venting step of the load lock chamber 26 in accordance with the first embodiment. The ordinate axis indicates the pressure [Pa] of the load lock chamber 26, and the abscissa axis indicates an exhaust period [second]. Figure 6B is a graph showing the air supply step of the load lock chamber 26 in accordance with the first embodiment. The ordinate axis indicates the pressure [Pa] of the load lock chamber 26, and the abscissa axis indicates a gas supply period [sec]. In Figures 6A and 6B, E ± XX is labeled x10 ^{± xx} .

This first embodiment is for example suitable for fine fluoroparticles having a diameter of 1.0 micron. As shown in FIG. 4, the movement speed of the fine fluorine particles having a diameter of 1.0 μm floating in the opposite direction of the wafer 8A in the load lock chamber 26 is 3.0E+04 Pa and 5.0E+. The pressure range of 04 Pa is the biggest. A period of time required to move the wafer 8A to the shield 19 by a distance of 0.05 mm is 27 seconds. Therefore, by maintaining a pressure between 3.0E+04 and 5.0E+04 Pa for 27 seconds or more, a fine fluorine particle having a diameter of 1.0 μm floating between the surface of the wafer and the shield 19 is The shield plate 19 collides at least once. The collision system is highly likely to cause the fine particles to adhere to the shielding plate 19, and thus reduce the adhesion of a fine particle to the surface of the wafer. This embodiment sets the pressure range between 3.0E-04 and 5.0E-04 Pa to the first pressure, and utilizes the thermal force generated in this pressure range to reduce the adhesion of the fine particles to the wafer 8A. In one example, this embodiment discusses fine fluorine particles having a specific gravity of 2,130 kg/m 3 , but this embodiment is applicable to other fine particles having different specific gravities.

In FIG. 5, S100 is a resist application step of feeding a wafer 8A that has been subjected to the application step to the exposure apparatus. S101 is a step of loading the wafer 8A into a wafer stocker in the exposure apparatus.

S102 is a step of controlling the temperature of the holding unit 18 to the temperature (24 degrees Celsius) and controlling the temperature of the shielding plate 19 to 4 degrees Celsius, and the temperature ratio of the holding unit is determined by the wafer stacker 16 The temperature of the introduced wafer 8A is as low as about 1 degree Celsius. By utilizing the thermophoretic force, by maintaining the temperature of the shield 19 below the temperature of the wafer 8A, this step effectively prevents the fine particles from adhering to the wafer 8A. S103 uses a temperature sensor (not shown) to detect or check the completion of temperature control of the holding unit 18 and the shielding plate 19. Upon completion of the temperature control, the process proceeds to the next step. When the temperature control has not been completed, the program returns to the previous step S102.

S104 is a step of opening the gate valve 20D, carrying the wafer 8A to the holding unit 18, and maintaining the load in the load lock chamber 26 before being vented or at atmospheric pressure. After the wafer 8A is carried, the gate valve 20 is closed. When the load lock chamber 26 is at the atmospheric pressure, fine particles having a diameter of 1.0 μm or less do not fall due to the gravity, but float due to the gas flow and the Brownian motion. Fine particles having a diameter greater than 1.0 micrometer move in the direction of gravity and will adhere to the wafer 8A. However, the shield 19 surrounds the wafer 8A in the load lock chamber 26 and is thus reduced to the adhesion probability of the wafer 8A.

When the density of the fine particles floating in the space between the shielding plate 19 and the wafer 8A is equal to the density of the fine particles floating in the other space This effect increases as the ratio between the volume of the wafer 8A near the inside of the shield and the volume outside the shield increases. In this particular embodiment, the volume ratio is about 0.003. Therefore, if 1,000 fine particles are moved in the gravity direction in the load lock chamber, only three of them are adhered to the wafer 8A, and the number of adhesion of the fine particles is reduced.

S105 moves the shield plate 19 toward the holding unit 18 and brings the shield plate 19 to the wafer 8A so as to surround the wafer 8A. The wafer 8A is completely surrounded by a small space and has a distance of 0.5 cm between the shield 19 and the surface of the wafer 8A. This embodiment provides an aperture to the shield plate 19 that has a conductivity that is vented and supplied to the load lock chamber 26 at the same time. Therefore, the inner side of the shielding plate 19 can be exhausted and supplied with the load lock chamber 26 at the same time. This embodiment controls the temperature and position of the shield 19 such that the space between the shield 19 and the wafer 8A has a temperature gradient of 40 [absolute temperature/cm].

S106 is a first exhaust step that uses the exhaust unit 4E to reduce the pressure of the load lock chamber 26 from the atmospheric pressure state up to 5.0E+04 Pa. When the conventional load lock chamber 26 is relieved of pressure, fine particles having a diameter of 1.0 μm or less start to move in the direction of gravity. On the other hand, in the load lock chamber 26 of this embodiment, fine particles having a diameter of 1.0 μm or less are moved toward the shield plate 19 due to the thermophoretic force, rather than in the direction of gravity. Further, as shown in the graph of FIG. 4, the gravity exceeds the thermophoresis force for the fine particles having a diameter of 1.5 μm or larger, and the fine particles do not move toward the shield plate 19.

S107 is a second exhausting step that reduces the pressure of the load lock chamber 26 at a constant exhaust ratio, as shown in FIG. 6A, such that the pressure of the load lock chamber 26 can fall at 5.0E+04 Pa and In the range between 3.0E+04 Pa and maintaining the first pressure for a minimum period of providing the effect of the thermophoretic force. This embodiment provides control and causes the orifice of the variable flow valve 33A to be small when the pressure of the load lock chamber 26 reaches 5.0E + 04 Pa, resulting in an exhaust velocity ratio of this embodiment. The first venting step is smaller. Due to the adhesion of the van der Waals force, the portion of the fine particles colliding with the shield plate 19 is adhered to the shield plate 19.

This embodiment requires 40 seconds to move the 1.0 micron fine fluorine particles in the upper direction to the shield 19 placed 0.5 cm away from the surface of the wafer 8A. In other words, within 40 seconds, the pressure is reduced to a range between 5.0E+04 and 3.0E+04 Pa, and the fine particles are collected. This period can be adjusted by the specific gravity of the fine particles, which mostly involves the processing steps of the wafer 8A.

S108 is a third venting step that vacuum pumps a first pressure ranging from 5.0E+04 to 3.0E+04 Pa to a second pressure of 1.0E-04 Pa. S109 is a step for moving the shield 19 in a direction opposite to the holding unit 18. The shield plate 19 is retracted to an appropriate position and the wafer 8A can be carried by the carrier unit 17B.

In general, the second venting step controls the temperature of the shield plate 19 installed in the load lock chamber to be lower than the temperature of the substrate while maintaining the pressure range between 10 Pa and 10,000 Pa up to 10 The period from seconds to 600 seconds is sufficient. The ‘“pressure range between 10 Pa and 10,000 Pa” The range of 98 percent of the maximum or maximum number of thermophoretic forces obtained from FIG. The period of 10 seconds is used for the minimum period required for the fine fluorine particles having a diameter of 1.0 μm to move to the shield plate 19, where the distance between the wafer 8A and the shield plate 19 is 0.2 cm, and the shield plate The temperature gradient of the space between 19 and the wafer 8A is 100 [absolute temperature/cm]. The period of 600 seconds is used for the maximum period required for the fine fluorine particles having a diameter of 1.0 μm to be moved to the shield plate 19, where the distance between the wafer 8A and the shield plate 19 is 1.0 cm, and the shield plate The temperature gradient of the space between 19 and the wafer 8A is 10 [absolute temperature/cm]. Although the exhaust rate is reduced without change in the second exhaust step in Fig. 6A, the gradient is not limited. Although the gradient of the second exhaust step in FIG. 6A is different from the gradient of the first exhaust step and the third exhaust step, the exhaust rates of the first to third exhaust steps may be reduced without change. This applies to the second and third embodiments which will be described with reference to Figures 7 and 8.

S110 is a carrying step under vacuum, which uses the carrier unit 17B to carry the wafer 8A to the exposure chamber 3 after opening the gate valve 20E, while maintaining the load lock chamber 26 by vacuum pumping. The second pressure. After the transfer, the gate valve 20E is closed. In this step, very few fine particles float in the load lock chamber 26, and the transport is less likely to cause it to adhere to the wafer 8A.

S111 is an exposure process. S112 is the same as S102, and thus its description will be omitted. S113 is configured to control the temperature of the jig 18 to a temperature of 22 degrees Celsius, and is lower than the temperature of the wafer carried by the exposure chamber 3 by 1 degree Celsius, and control the temperature of the shielding plate 19 to 12 degrees Celsius. Step Step. S114 is a carrying step under vacuum, by which the carrier unit 17B carries the wafer 8A to the holding unit 18 in the loading and interlocking chamber 26 after opening the gate valve 20E, and the loading is mutually The lock chamber 26 is in the second pressure state and holds the wafer therein. After the transfer, the gate valve 20E is closed.

S115 is a step of moving the shielding plate 19 toward the holding unit 18. Since this step is similar to S105, its description will be omitted. S116 is a first air supply step for supplying air such that the pressure in the load lock chamber 26 is changed from the second pressure 1E-04 to 3.0E + 0.4 Pa.

S117 is a second air supply step that supplies air until the pressure in the load lock chamber 26 becomes 5.0E+04 Pa. In the first gas supply step, fine particles that have swirled in the load lock chamber are dropped, but the hot spray force is applied close to the wafer 8A, and the fine particles are moved to the shield plate 19 to reduce Adhesion to the wafer 8A. Similar to S107, this embodiment sets the period required to move a 1.0 micron fine fluorine particle to the shield 19 to 40 seconds, and the shield is placed away from the surface of the wafer 8A in the upper direction by 0.5. Centimeters.

S118 is a third air supply step that supplies air until the pressure in the load lock chamber 26 can be an atmospheric pressure. In this step, the fine particles float, which have swirled in the first and second gas supply steps. The shield 19 surrounds the wafer 8A and reduces the adhesion of the fine particles to the wafer 8A. S119 is a step of retracting the shield plate 19 to an appropriate position in which the wafer carrier unit 17A can carry the wafer 8A. S120 is the wafer 8A in the load lock chamber 26 at the atmospheric pressure download The step of feeding to the wafer stocker 16. S121 is a step of unloading the wafer to the atmospheric air side by a wafer stocker in the exposure apparatus.

Roughly, similar to the second venting step, the second gas supply step controls the temperature of the shield plate 19 installed in the load lock chamber to be lower than the temperature of the substrate while maintaining the pressure range at 10 The period from 10 seconds to 600 seconds between Pa and 10,000 Pa is sufficient. The "pressure range between 10 Pa and 10,000 Pa" and the "Period of 10 seconds to 600 seconds" are required for the same reason as the second exhaust step. Although the gas supply rate is reduced without change in the second gas supply step in Fig. 6B, the gradient is not limited. Although the gradient of the second gas supply step in FIG. 6B is different from the gradient of the first gas supply step and the third gas supply step, the gas supply rate of the first to third gas supply steps may be increased without change. This applies to the second and third embodiments which will be described with reference to Figures 7B and 8B.

From the above description, in the exhaust/air supply step of the load lock chamber 26, the first pressure range between 5.0E+04 Pa and 3.0E+04 Pa is maintained for a certain period of time to maximize the thermophoretic force, And reducing the adhesion of the fine particles to the surface of the wafer.

Second specific embodiment

This embodiment differs from the first embodiment in that in the second exhaust step S107 and the second air supply step S117, this embodiment allows the pressure in the load lock chamber 26 to be at a certain pressure Change in scope. Figure 7A is a graph showing an exhaust step of the load lock chamber 26 in accordance with the second embodiment. The ordinate axis indicates the load lock chamber The pressure of 26 [Pa], and the axis of abscissa indicates an exhaust period [seconds]. Figure 7B is a graph showing a gas supply step of the load lock chamber 26 in accordance with the second embodiment. The ordinate axis indicates the pressure [Pa] of the load lock chamber 26, and the abscissa axis indicates a gas supply period [sec].

A second venting step S107 will be described which reduces the pressure of the load lock chamber 26 to a range between 3.0E+04 Pa and 5.0E+04 Pa. When the pressure of the load lock chamber 26 reaches 100 Pa, the exhaust valve is closed and the exhaust is temporarily stopped. This action reduces the Brownian motion of the gas that affects the fine particles and enhances the relative thermophoretic force. The pressure in the load lock chamber 26 is gradually increased due to the emitted and leaked gases, but the thermophoretic effect is so large in this pressure range that the adhesion of the fine particles can be reduced. In this pressure range, the fine particles inside the shield plate 19 are not dropped by the gravity, but the thermophoretic force is moved to the shield plate 19 and adhered to the shield plate 19.

The second air supply step S117 of the second embodiment will be described. This air is supplied until the pressure in the load lock chamber 26 reaches 100 Pa. Once the pressure in the load lock chamber 26 reaches 100 Pa, the flow variable valve 33B is closed to temporarily stop the supply. This action reduces the Brownian motion of the gas that affects the fine particles and enhances the relative thermophoretic force. As such, the second embodiment can reduce the adhesion of the fine particles to the wafer 8A.

Third specific embodiment

This embodiment is suitable for reducing the subtle diameter of 1.0 micron. Fluoride particles. This embodiment differs from the first embodiment in that the specific embodiment controls the degree of orifice of the exhaust valve of the load lock chamber 26 in the second exhaust step, and controls the exhaust flow rate and maintains 4.0E+04 Pa. The first pressure system of this embodiment is 4.0E+04 Pa.

As shown in FIG. 4, when the pressure of the load lock chamber 26 is 4.0E+04 Pa, the rate in the opposite direction to the gravity becomes maximum, where the fine particles are moved from the wafer 8A to the The distance of the shield 19 is 215 seconds. Therefore, the fine particles floating between the surface of the wafer and the shielding plate 19 collide with the shielding plate 19 at least once by maintaining the pressure state of 4.0E+04 Pa for 215 seconds. The collision system is highly likely to cause the fine particles to adhere to the shielding plate 19, and thus reduce the adhesion of a fine particle to the surface of the wafer.

At a pressure of 3.0 E-04 Pa of the load lock chamber 26, it took 221 seconds for the fine particles to move to the shield plate and 230 seconds at a pressure of 5.0 E-04 Pa, reducing the throughput of the apparatus. Thus, this embodiment sets the pressure of 4.0E+04 Pa to the first pressure and utilizes the thermal force generated in this pressure range to reduce the adhesion of the fine particles to the wafer 8A. This configuration reduces fine particles having a large diameter and a large mass in a minimum period.

Figure 8A is a graph showing the venting step of the load lock chamber 26 in accordance with the third embodiment. The ordinate axis indicates the pressure [Pa] of the load lock chamber 26, and the abscissa axis indicates a period [second]. Figure 8A specifies the carrier step at the atmospheric pressure, the first venting step, the second venting step, and the third venting step, and the carrying step under vacuum And a carrying step of the wafer 8A and a moving step of the shielding plate 19. This particular embodiment is different from the first embodiment of the second venting step.

The second venting step will now be described which switches to the slow venting to maintain 500 Pa and provides the slow venting and the slow supply after the pressure of the loading lock chamber 26 reaches 500 Pa. gas. The exhaust flow rate of the load lock chamber 26 is controlled by controlling the degree of orifice of the flow variable valve 33A provided between the exhaust unit 48 and the load lock chamber 26. The supply air flow rate of the load lock chamber 26 is controlled by controlling the degree of orifice of the flow variable valve 33B provided between the air supply unit 29 and the load lock chamber 26.

Figure 8B is a graph showing the gas supply step of the load lock chamber 26 in accordance with this embodiment. The ordinate axis indicates the pressure [Pa] of the load lock chamber 26, and the abscissa axis indicates a period [second]. Figure 8B specifies a carrier step under vacuum, the first gas supply step, the second gas supply step, and the third gas supply step, and the carrier step at atmospheric pressure and the loading of the wafer 8A The sending step and the moving step of the shielding plate 19. This particular embodiment is different from the first embodiment of the second gas supply step. Control of the second gas supply step is maintained at 500 Pa in the load lock chamber 26.

The load lock chamber 26 of the third embodiment is always capable of generating a maximum thermal force and provides a reduced adhesion of the fine particles than the load lock chamber 26 of the first and second embodiments. Larger effect. Therefore, the third embodiment reduces the fine particles to the wafer 8A. Adhesion.

Although the above specific embodiments discuss applications for semiconductor wafers, such as germanium substrates, substrates to which the present invention is applicable are not limited to the wafers. The vacuum chamber allows the thermophoretic force to be applied to floating particles near the surface of the substrate and reduces the adhesion of the particles to the surface of the substrate. Although this embodiment configures the surface of the substrate perpendicular to the direction of gravity, the present invention does not limit the orientation of the substrate.

Although the present invention has been described with reference to the preferred embodiments thereof, it is understood that the invention is not limited to the exemplary embodiments disclosed. The scope of the following patent application is to be accorded the broadest description

1‧‧‧Inspired laser

2‧‧‧Light source radiating parts

2A‧‧‧radiation point

2B‧‧‧Light source lens

3‧‧‧Exposure room

4A‧‧‧Exhaust unit

4B‧‧‧Exhaust unit

5‧‧‧Lighting optical system

5A‧‧‧Lens

5B‧‧‧Lens

5C‧‧‧Lens

5D‧‧‧Lens

6‧‧‧Photomask Workbench

6A‧‧‧Photomask

7‧‧‧Projection optical system

7A‧‧‧Lens

7B‧‧‧Lens

7C‧‧‧Lens

7D‧‧‧Lens

7E‧‧‧Lens

8‧‧‧ Wafer Workbench

8A‧‧‧ wafer

9‧‧‧Support members

10‧‧‧Support members

11‧‧‧Support members

12‧‧‧Photomask Stacker

13‧‧‧Photomask Vehicle Room

13A‧‧‧Cover open parts

14A‧‧‧Photomask carrier unit

14B‧‧‧Photomask carrier unit

15‧‧‧Photomask alignment category display

15A‧‧‧Alignment marks

16‧‧‧Wafer Stacker

17A‧‧‧ wafer carrier unit

17B‧‧‧ wafer carrier unit

18‧‧‧ Holding unit

18A‧‧‧Support pin

19‧‧‧Shield

20A‧‧‧ gate valve

20B‧‧‧ gate valve

20C‧‧‧ gate valve

20D‧‧‧ gate valve

20E‧‧‧ gate valve

21‧‧‧ drive unit

22A‧‧‧Temperature Control Unit

22B‧‧‧Temperature Control Unit

23‧‧‧ pipes

24‧‧‧Load lock room

26‧‧‧Load lock room

27‧‧‧Contained containers

28‧‧‧Cars holding unit

29‧‧‧ gas supply unit

30‧‧‧Control unit

31‧‧‧Photo Mask Card

32‧‧‧Pressure detection unit

33A‧‧‧Flow variable valve

33B‧‧‧Flow variable valve

34‧‧‧SMIF indicator

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross-sectional view showing an exposure apparatus according to a first embodiment of the present invention.

Figure 2 is a schematic cross-sectional view of the load lock chamber of Figure 1.

Figure 3 is a graph indicating the thermophoretic force that affects the fine fluorine particles floating in the load lock chamber of Figure 1.

Fig. 4 is a graph showing the relationship between the moving speed of the fine fluorine particles and the pressure.

Figure 5 is a flow diagram of a first embodiment of the present invention.

Figure 6 is a graph of the pressure curve of a load lock chamber in accordance with a first embodiment of the present invention.

Figure 7 is a loading lock chamber in accordance with a second embodiment of the present invention. A graph of the pressure curve.

Figure 8 is a graph of the pressure curve of a load lock chamber in accordance with a third embodiment of the present invention.

Claims (11)

A method of changing the atmosphere in a load lock chamber (26), the load lock chamber being contained within an exposure apparatus, comprising a vacuum chamber (3) constructed for use in a vacuum chamber in a vacuum environment Exposing the substrate to the pattern, the method comprising: loading the substrate into the load lock chamber, the gas pressure in the load lock chamber is changed, and the substrate is transferred to or from the vacuum chamber via the load lock chamber The chamber is transported; controlling the temperature of the loaded substrate to maintain the temperature of the loaded substrate; changing the gas pressure in the load lock chamber; and controlling the temperature of the dust collecting unit disposed in the load lock chamber, such that The temperature of the dust collection unit is maintained below the maintained temperature of the substrate such that the dust collection unit collects dust by a predetermined temperature gradient between the dust collection unit and the substrate, wherein the load lock chamber additionally A holding unit configured to hold the substrate, and a driving unit configured to move the dust collecting unit and the holding unit relative to each other, and wherein the dust collecting sheet is controlled in parallel The temperature of the element additionally includes controlling the drive unit such that the distance between the dust collection unit and the substrate changes to produce a predetermined temperature gradient therebetween. A method of changing the atmosphere in a load lock chamber as in the first aspect of the patent application, wherein the predetermined temperature gradient is 10 K/cm or higher. For example, the first item of the patent application scope changes the atmosphere of the load-locking room. The method wherein the vacuum chamber is connected to the load lock chamber via a gate valve. The method of claim 1, wherein the changing the pressure in the load lock chamber comprises maintaining a pressure in the load lock chamber in a range of 10 Pa (Pa) to 10000 Pa, and The period is in the range between 10 seconds and 600 seconds. The method of changing the atmosphere in the loading interlocking chamber according to the first aspect of the patent application, wherein the relative movement of the dust collecting unit and the holding unit to each other comprises moving the dust collecting unit in a direction toward the holding unit, so that the dust collecting unit covers The substrate. The method of changing the atmosphere in the loading interlocking chamber according to the first aspect of the patent application, wherein the temperature of the dust collecting unit becomes a constant, and a temperature gradient between the dust collecting unit and the substrate is set to the predetermined temperature gradient. The method of changing the atmosphere in the loading interlocking chamber according to the first aspect of the patent application, wherein the temperature gradient between the dust collecting unit and the substrate is controlled such that the temperature of the dust collecting unit facing the surface of the substrate is lower than the surface of the substrate The temperature toward the surface of the dust collecting unit. The method of changing the atmosphere in the load lock chamber according to the first aspect of the patent application, further comprising transmitting the substrate to or from the vacuum chamber via the load lock chamber, and exposing the substrate to the vacuum chamber a pattern, wherein the pattern comprises a far ultraviolet light pattern. The method of changing the atmosphere in the loading interlocking chamber according to the first aspect of the patent application, wherein the dust collecting unit covers the substrate to reduce adhesion of dust to the substrate. A method of changing the atmosphere in a load lock chamber (26), the load lock chamber being contained within an exposure apparatus, comprising a vacuum chamber (3) constructed for use in a vacuum chamber in a vacuum environment Exposing the substrate to the pattern, the method comprising: loading the substrate into the load lock chamber, the gas pressure in the load lock chamber is changed, and the substrate is transferred to or from the vacuum chamber via the load lock chamber The chamber is transported; controlling the temperature of the loaded substrate to maintain the temperature of the loaded substrate; changing the gas pressure in the load lock chamber; and controlling the temperature of the dust collecting unit disposed in the load lock chamber, such that The temperature of the dust collecting unit is maintained below the maintained temperature of the substrate such that the dust collecting unit collects dust by a temperature gradient between the dust collecting unit and the substrate. A method of changing the atmosphere in a load lock chamber (26), the load lock chamber being contained within an exposure apparatus, comprising a vacuum chamber (3) constructed for use in a vacuum chamber in a vacuum environment Exposing the substrate to the pattern, the method comprising: loading the substrate into the load lock chamber, the gas pressure in the load lock chamber is changed, and the substrate is transferred to or from the vacuum chamber via the load lock chamber The chamber is transferred; controlling the temperature of the loaded substrate; changing the gas pressure in the load lock chamber; and controlling the temperature of the dust collecting unit disposed in the load lock chamber, such that The temperature of the dust collecting unit is kept lower than the temperature of the substrate, so that the dust collecting unit collects dust by a predetermined temperature gradient between the dust collecting unit and the substrate, wherein the loading interlocking chamber additionally includes being constructed a holding unit for holding the substrate, and a driving unit configured to move the dust collecting unit and the holding unit relative to each other, and a temperature parallel to the temperature of the dust collecting unit, the method further comprising controlling the driving unit, The distance between the dust collection unit and the substrate is varied to produce a predetermined temperature gradient therebetween.