TWI469832B - Object cleansing method and object cleansing system - Google Patents

Description

Object cleaning method and object cleaning system

The present invention relates to a semiconductor substrate/glass substrate/lens/disk member/precision machined member/molded resin member or the like as an object (particularly, a semiconductor substrate having an aluminum material such as aluminum wiring on its surface). a method of predetermining a predetermined portion or a predetermined surface of the object, and the system (for example, an object cleaning method and an object cleaning system), and more specifically, cleaning of the site or surface, removal of the object not used at the site, and Method of peeling, polishing and processing of the surface of the object, and processing of the system (for example, a semiconductor stripping device such as a resist stripping device, a polymer stripping device, and a cleaning device, a printed circuit board cleaning device, a mask cleaning device, etc.) method).

In the pre-semiconductor processing step, 50 to 100 cleanings are repeated for one wafer. The object to be cleaned is an organic substance or a fine particle such as a resist film or a polymer film which affects the reliability of the element. In this washing step, generally, a combination of an alkali cleaning solution and an acid cleaning solution and a drug such as a mixture of sulfuric acid and hydrogen peroxide are used, and in addition, in the washing step for removing the residue, a large amount is used. Pure water. Further, in terms of removing the resist, a plasma ashing apparatus is generally used, and subsequent cleaning of the residue and impurities uses other cleaning means. Further, in terms of removing the polymer film, a waist-based organic solvent is often used. This liquid can also be used for the removal of the resist. Here, the liquid cleaning system for cleaning and removing the film used in the above-described prior art has the following disadvantages: 1) high price, 2) large environmental load and special drainage treatment equipment, and 3) for ensuring workers The safety and hygiene device must be large, and a large amount of pure water must be used to wash the liquid in the cleaning of the liquid used. 4) The removal of the film to the cleaning cannot be performed by one device.

Further, if it is limited to the washing step in which the chemical liquid is not used, the following main techniques are currently available. First of all, the ultrasonic cleaning device is the most widely used cleaning technology, and can be combined with various cleaning liquids in addition to pure water. The disadvantage is that the cavitation phenomenon (which is different from the cavitation phenomenon described later in the present invention) may damage the soft material, the brittle material and the fine pattern. Therefore, although the frequency is increased, etc., there is a conflict with the cleaning power. Secondly, the water spray cleaning device is suitable for cleaning large-scale systems. The disadvantage is that there must be high pressure (several Mpa to 20 MPa), and it is not suitable for objects with fine patterns. Moreover, the brush cleaning device can be combined with various cleaning liquids in addition to pure water. Disadvantages are not suitable for surfaces with deep grooves and holes. Moreover, since the surface of the object is in direct contact with the brush, there is a possibility of generating dust and scratches.

In addition, there is a cleaning device that illuminates only water vapor. The environmental load of the device is also very small when the device is not used. However, this device has the following disadvantages: 1) Since the droplets are not used, the effect of the object which is strongly bonded such as the photoresist on the wafer and the foreign matter is small, and 2) the pressure of the vapor generator is unique. The parameters, so it is impossible to adjust the optimum conditions of the object.

Therefore, in recent years, it has been proposed to use a cleaning device that combines water vapor and liquid fine particles (for example, Patent Document 1 to be described later). In this technique, first, vaporized water (water vapor) infiltrates into the resist film and reaches the interface between the resist film and the surface of the object, and weakens the bonding force of the resist film of the interface to make the resist film Lifting off the surface of the object. Next, a phenomenon occurs in which a water-repellent film (water mist) containing a liquid water fine particle accompanying a predetermined ejection pressure physically acts on the resist film to peel the resist film from the interface. Then, in paragraph number 0019 of Patent Document 1, a cavitation phenomenon using a thermal effect phenomenon as a basic principle of the technique is described. Specifically, it is a mechanism for generating a vibration having a certain frequency (10 kHz to 1 MHz) by the above-described heat exchange when mixing normal temperature pure water and high temperature water vapor. Then, using this vibration, water molecules are decomposed into hydrogen ions and hydroxide ions, and the high energy generated when the unstable ions are returned to the water molecules again is converted into a mechanical impact.

[Patent Document 1] W020061/018948

However, when a cleaning device that combines water vapor and water shown in Patent Document 1 is used, the following problems occur: First, a certain degree of time required for the reaction of the penetration of water molecules, and The misty mist directly collides with the resist film and the particles to remove the film and the dirt. Therefore, there is a problem that the soaking time of the water molecules is limited, and secondly, the cleaning power is insufficient and the object cannot be sufficiently removed. The dirt of the object, or conversely, the cleaning power is too strong to damage the situation of the object. At this time, some countermeasures are taken, for example, in the case of the former, the discharge pressure is increased, and in the latter case, the discharge pressure is lowered. As described above, in the current state, the cleaning force can be adjusted only by the action of fluid mechanics (collision force, etc.). However, at this time, there is a concern that in the former, the vapor temperature is raised by raising the discharge pressure, the material having low heat resistance cannot be targeted, or the collision force is too strong, and damage to the object may occur. On the other hand, in the latter, there is a problem in that the problem of damage to the object can be avoided because the discharge pressure is low, but the cleaning of the object is insufficient. Accordingly, a first object of the present invention is to provide a means for ensuring that the permeation time of water molecules is not restricted and that the cleaning is carried out without any damage to the object.

Further, the inventors of the present invention have found from their experience that when the semiconductor substrate is cleaned by a multiphase flow of water and water vapor, the aluminum formed on the surface of the semiconductor substrate is quickly corroded. Thus, if the aluminum is corroded before the next treatment, the semiconductor device may not operate, and the yield may be deteriorated. Accordingly, a second object of the present invention is to provide a means for preventing aluminum which is formed on the surface of the semiconductor substrate from being corroded for a long period of time even when the semiconductor substrate is cleaned by multiphase flow of water and water vapor.

The inventor of the present invention focused on the aforementioned cavitation phenomenon completely different from the previous action sequence, and by controlling the degree of the cavitation phenomenon on the object, it was found that the treatment suitable for the object can be effectively and easily performed. The present invention has been completed.

Further, in order to improve the detergency, the inventors of the present invention did not pay attention to the pressure of the gas but focused on the velocity of the droplets contained in the multiphase fluid, and continually conducted careful research to increase the speed. Then, when it is found that the specific droplets are used to increase the droplet velocity, the object can be removed by the sufficient impact force without causing the object to be cracked or the surface pattern to collapse. this invention.

The present invention (1) is a method for cleaning an object, comprising: irradiating a target by irradiating a nozzle with a multiphase fluid containing water vapor of a continuous phase and water droplets of a dispersed phase which are produced by mixing water vapor and water in a mixing portion; In the method of the object, the mixing unit is provided on the upstream side of the nozzle, and has a water inlet portion that is partially open on the inner wall surface, and the nozzle is an ultrahigh-speed nozzle, and the inner wall surface of the mixing portion and the inner wall surface of the nozzle are formed substantially. a continuous curved surface, wherein water is mixed from the inner wall surface of the mixing portion to the water vapor flowing in the mixing portion, and water is moved from the inner wall surface of the mixing portion along the inner wall surface of the nozzle, and the nozzle is The outlet exits the aforementioned multiphase fluid.

In the method of the invention (1), the nozzle has a diameter that decreases in diameter from the upstream side of the nozzle toward the nozzle outlet, and the end of the diameter is expanded by the throat portion having the smallest cross-sectional area. Wide structure.

In the method of the invention (1) or (2), the mixing unit has a cylindrical shape.

The invention (4) is the method of any one of the inventions (1) to (3), wherein the speed of the water droplets is in a range of 100 to 600 m/s.

According to a fifth aspect of the invention, the method of any one of the aspects (1) to (4), wherein the temperature of the multiphase fluid reaching the object is 50° C. or higher, and the pH of the multiphase fluid reaching the object is 7 To the range of 9.

In the method of the invention (5), the distance between the multiphase fluid ejection outlet and the object is 30 mm or less.

In the method of any one of the inventions (1) to (6), the object of the invention is the semiconductor substrate having an aluminum material such as aluminum wiring on the surface.

The present invention (8) is a system for cleaning an object by irradiating a multiphase fluid containing water vapor and water droplets through a nozzle, and has a water vapor supply means (for example, a water vapor supply part (A)) for supplying water vapor; a water supply means for supplying a liquid (for example, a pure water supply portion (B)); and a nozzle for irradiating the multiphase fluid; characterized in that the mixing portion (for example, the mixing portion 144) is disposed upstream of the nozzle, And a water introduction portion (for example, 144a) that can mix water to the inner wall surface of the water vapor flowing from the inner wall surface, and the nozzle is an ultrahigh-speed nozzle (for example, the nozzle 141), and the inner wall surface of the mixing portion A substantially continuous curved surface is formed on the inner wall surface of the nozzle.

In the method of the invention (8), the nozzle has a diameter that decreases in diameter from the upstream side of the nozzle toward the nozzle outlet, and the end of the diameter is expanded by the throat portion having the smallest cross-sectional area. Wide structure.

The invention (10) is the system of the invention (8) or (9), wherein the mixing portion has a tubular shape.

Hereinafter, the meaning of each term in the specification will be described. First, the term "water droplet" means, for example, a concept including minute water droplets from a wet saturated vapor in addition to water droplets from water. The "multi-phase fluid" refers to a fluid having a plurality of fluid components such as two fluids and three fluids, and examples thereof include 1) saturated water vapor and pure water droplets having a boiling point or lower, and 2) heating water vapor and boiling point or lower. Pure water droplets, 3) complex inert gas or clean high pressure air in the above 1) or 2). However, oxygen gas and other reactive gases can also be used when it is not used for the purpose of oxidation and chemical reaction of the object. Further, from the viewpoint of using aluminum to prevent corrosion, it is preferable to use a two-phase flow which is only water and water vapor or a combination of the above two-phase flow and an inert gas. The "object" is not particularly limited, and examples thereof include an electronic component, a semiconductor substrate, a glass substrate, a lens, a disk member, a precision machined member, and a molded resin member. The term "treatment" is not particularly limited as long as it is applied to an object, and examples thereof include peeling, washing, and processing. The term "water" refers to water which is characteristic of the degree of pure water or ultrapure water, and is used for the purpose of cleaning the semiconductor device, such as a cleaning process such as a small foreign matter or a metal ion on the object. In the use of small foreign matter and metal ions, which are not intentionally generated on the object, a tap water having a low level is included. The term "system" refers to a position (for example, a device) in which physical components are separated from each other except for the "device" in which the components are integrated, or the components are not communicated with each other. When the information is connected, the whole has the components that have the functions specified in the scope of the patent application, that is, it conforms to the system. The term "ultra-high speed nozzle" means a nozzle that accelerates a droplet to a speed above the speed of sound.

Here, in order to make the difference with the cavitation phenomenon of the other action sequence known in the field of object processing more clear, the cavitation phenomenon at the time of collision of the droplet of the present invention will be described in detail with reference to the drawings. Furthermore, the action sequence described herein is only for prediction. Therefore, the present invention is not limited by the order of action.

First, the general concept of cavitation is explained below.

In general, when the temperature of the liquid is higher than the saturation temperature of the pressure, boiling starts, and even if the pressure of the liquid becomes lower than the saturation pressure of the temperature, the liquid starts to boil. That is, vapor bubbles are generated in the liquid. Such a bubble which is not caused by a change in temperature but which is caused by a decompression effect is generally called a cavitation bubble. High pressure is generated due to shrinkage and collapse of the bubble, and erosion, noise, and the like are generated. This phenomenon is called cavitation.

Conventionally, in an ultrasonic cleaning device used for cleaning, cavitation is generated by an action sequence as follows (Fig. 24).

1. Use the ultrasonic generator to transmit sound waves into the medium.

2. The sound wave is compressed and decompressed in a fast cycle and passed through the medium.

3. During the transfer from compression to decompression, local pressure is reduced to below the saturated water vapor pressure.

4. At this point, the growth of bubbles (normal temperature boiling) begins to occur.

5. In addition, non-condensable gases dissolved in the vehicle are also mixed into the enlarged growth vapor bubbles.

6. Bubbles continue to grow.

7. The bubble is compressed by heat by the subsequent compressive force and has high energy.

8. The bubble collapses and collapses at the end.

9. When crushed, it becomes a localized impact energy and decomposes the dirt around it.

10. Sound waves usually generate standing waves by passing the traveling waves in the medium and the reflected waves reflected on the liquid surface.

11. At this time, the cavitation phenomenon is striped in the vehicle liquid along the maximum sound pressure body.

Then, according to the method of the present invention, the mechanism of occurrence of cavitation in the collision of the generated droplets can be considered, and the example of the past report is used as a reference (martin Rein, 〝Drop-Surface Interactions (Cism Internation Centre For Mechanical Sciences Courses and Lectures) pp. 39-102, Martin Eein ed., Springer-Verlag, 2002,).

1. When a droplet collides with a solid boundary interface at a certain velocity, the kinetic energy of the droplet is converted into a pressure energy source, and a high pressure is generated at the interface between the droplet and the solid boundary interface (Fig. 25).

2. The generated pressure acts as a pressure wave (compression wave) to propagate the inside of the droplet to the upper side, and reaches the boundary interface between the droplet and the surrounding gas, that is, the free interface (Fig. 26).

3. The acoustic impedance of water is much larger than the acoustic impedance of the surrounding gas, resulting in impedance mismatch, and the pressure wave is approximately 100% reflective. That is, since the propagation of the gas around the pressure wave becomes very small, the pressure change at the free interface can be suppressed to a small extent (Fig. 27).

4. The pressure change at the free interface becomes smaller because the expansion wave that cancels the compression wave is generated, that is, a lower pressure wave is generated than the surroundings, and is propagated to the inside of the liquid.

5. The expansion wave that propagates into the interior of the droplet reduces the pressure inside the droplet. If the temperature of the droplet is about 30 ° C, it is reduced by about 0.04 atmosphere. If it is about 60 ° C, it is reduced by about 0.2 atmosphere. If it is about 80 ° C, it is lowered by about 0.5 atmosphere. Then, it starts to boil, and bubbles are generated and grows. Figures 28 and 29).

6. The generated vapor bubbles are also introduced into the liquid and become non-condensable gas while growing, and become larger.

7. When the bubble of full growth reaches the limit of growth, it begins to rebound and shrinks. Since the shrinking process is sharply generated compared to the expansion process, the bubble is sharply contracted, and the internal pressure of the bubble is higher than the pressure at the start of growth, and an extremely high pressure can be achieved. This high pressure is called pressure when the bubble collapses.

8. Bubble collapse is also induced by disturbances in the surrounding conditions of the bubble. In addition, the bubbles do not necessarily collapse alone, but collapse as a group of bubbles in which the bubbles are accumulated. According to the report, the bubble collapse pressure at this time is more than several hundred times the pressure of a single bubble collapse.

9. The bubble collapse pressure generated inside the droplet propagates as a pressure wave (compression wave) inside the droplet and reaches the contact surface of the droplet with the solid surface, causing a very large pressure on the solid surface. This is the collapse pressure of the cavitation phenomenon generated when the droplet collides, and the pressure is used for cleaning.

It is essential in the present invention to maintain the thermal environment around the droplets at a sufficiently high temperature or to prevent the leakage of heat caused by the droplets by means of water vapor. Therefore, even if the pressure drop caused by the expansion wave inside the droplet is not significant, it is a condition that a sufficient bubble can be generated. Because of this characteristic, as with other inventions, even if the droplets have a rapid velocity without colliding with the solid surface, it is sufficient as long as a certain degree of compression wave can be generated.

When compared with other inventions, the point of generating cavitation by droplets having a velocity generated by a low-order pressure is the most particular point of the present invention.

According to the present invention, the conventional method of controlling the impact force on the object by the adjustment of the discharge pressure (the action of the fluid mechanics) is different, and is configured to utilize the droplet collision generated by the droplet colliding with the surface of the object. When the object is treated by the cavitation phenomenon, the following problems and problems can be solved. This problem is a well-known problem due to the level of the discharge pressure. Specifically, the collision force becomes too strong. There is a problem that damage to the object is caused, and the problem that the object is injured due to the low discharge pressure can be avoided, but the cleaning of the object is insufficient. Further, since the temperature of the droplet at the time of collision is highly correlated with the cavitation phenomenon at the time of collision of the droplet, the degree of the cavitation phenomenon (the presence or absence and degree of occurrence) can be easily controlled by changing the temperature of the droplet. Further, under the low discharge pressure, the treatment of the object can be efficiently performed by increasing the temperature of the droplet, so that the problem caused by the high discharge pressure can be avoided. Further, when the gas is water vapor, even if the heat of the water vapor is moved to another medium, the temperature of the entire system can be prevented from being lowered as a result of the latent heat of the water vapor.

A more specific effect of the present invention is as follows. (1) A turtle on a film that causes a film peeling due to a shock wave caused by a high-speed side jet and a bubble collapse caused by a collision of a droplet, and an impact force (cavitation phenomenon) caused by a chain reaction by a shock wave. Crack and hole. (2) A jet flow and a shock wave due to the liquid droplets, a chain reaction due to the shock wave, and a high-speed side jet flow are generated, and the film is peeled off by the crack and the hole as described in (1). (3) The object material is embrittled by the vapor of water having a large heat temperature energy, or stress is generated to weaken the adhesion of the interface between the object and the substrate. (4) The combination of the above functions is changed in accordance with the object, whereby the object to be cleaned and the object to be removed can be expanded. (5) The present invention can be applied not only to the removal of impurities but also to the removal of the photoresist which is not used after the etching step and the ion implantation step, and the removal of the polymer which is not used after the etching step.

Further, according to the inventions (1) to (4) and (8) to (10), the speed of water droplets is made faster by using an ultrahigh speed nozzle. Therefore, the droplets are subdivided to make the droplet diameter small. Therefore, it is difficult to produce droplets having a large diameter which is a cause of cracking of the wafer and collapse of the pattern, and the problem is not easily generated even if the pressure is increased.

Further, when an ultrahigh-speed nozzle is used, an action indicating the following two points is observed in a multiphase fluid which ejects water vapor and water droplets, and a multiphase fluid of air and water droplets.

First, it is clear that an object such as a pressure wave is observed near the outlet in the nozzle by using an ultra-high-speed nozzle to eject a multiphase fluid of water vapor and water (the 30th example). According to this, the effect is obtained in that the droplets are more subdivided in the nozzle and the droplet diameter is made smaller, so that even if the pressure is raised, the problem of cracking of the wafer and collapse of the surface pattern is not caused.

Second, the relationship between gas pressure and droplet velocity and/or average particle size. When the gas pressure is increased, in the multiphase fluid of air and water, the droplet velocity becomes higher as the pressure increases, and conversely, in the case of water vapor and water, the measurement can be performed until the predetermined pressure is reached, but Measurements cannot be made when the predetermined pressure is exceeded (28th example). Furthermore, when the relationship between the observed gas pressure and the average particle diameter of the water droplets is known, in the multiphase fluid of air and water, the particle diameter does not depend on the gas pressure, but in the case of water vapor and water, The data of the average particle size exceeding the predetermined pressure becomes untrustworthy (the 29th case). This refers to the pressure of a region that is measurable in the multiphase fluid of air and water, and not in the multiphase fluid of water vapor and water. That is, under this pressure, the multiphase fluid of water vapor and water, and the multiphase fluid of air and water, at least represent some different actions. The difference in the action is not clear, and the main reason for the inability to measure may be that the droplet velocity is too fast or the droplet diameter is too small.

Water is mixed into the water vapor from the wall surface of the mixing portion on the upstream side of the nozzle, a water film is formed on the wall surface, and is ejected from the nozzle outlet, and a multiphase fluid of water droplets and water vapor is ejected. The ejected droplets generate a cavitation phenomenon on the surface of the object by colliding with the surface of the object and locally generating a low pressure portion in the droplet by the aforementioned action sequence.

In addition, since the nozzle for widening is reduced in diameter from the upstream side of the nozzle toward the nozzle outlet, and the structure is expanded by the throat which is the smallest cross-sectional area, the structure is expanded. The water film is formed on the inner wall of the nozzle by the water mixed in the mixing portion, and the water vapor is ejected through the central portion of the nozzle. At this time, the water vapor is accelerated between the throat and the nozzle outlet. And, the water is accelerated by being pulled by the accelerated steam.

Further, according to the invention (5), it is possible to achieve the following effects: in addition to the sufficient impact obtained by the cavitation phenomenon described above, when the semiconductor substrate is cleaned by a multiphase flow of water and water vapor, The surface of the semiconductor substrate is not easily corroded during the long period of aluminum. For example, it is possible to obtain an effect that, after the dry etching of aluminum, if the resist on the object is peeled off by the method of the invention (5), the aluminum wiring does not corrode until the next step.

According to the invention (6), the following effects can be obtained: since the distance between the multiphase fluid ejection outlet and the object is short, the multiphase fluid is not easily introduced into the carbon dioxide in the atmosphere, so that the pH is not easily biased toward acidity, and the effect can be more effectively exerted. Prevent the effects of aluminum corrosion.

Hereinafter, the present invention will be specifically described by using a "wafer cleaning device" as an object processing device as an optimum embodiment. In addition, the present preferred embodiment is only the best illustration, and does not limit the scope of the technology of the present invention at all.

Composition of multiphase fluid

First, the multiphase fluid of the best mode is a water droplet containing a continuous phase of water vapor and water produced by mixing water vapor with water. Here, the "water droplet" is composed of pure water (in addition to a part of water vapor having a high humidity) which is an object which is composed of a material which is resistant to chemicals. Further, the above-mentioned multiphase fluid may optionally contain an inert gas such as argon or nitrogen, and clean high-pressure air. However, from the viewpoint of preventing corrosion of aluminum, any gas is preferably argon or an inert gas.

Here, the reason why the water vapor is used is that the latent heat can be utilized in addition to the heat, and the temperature is hardly lowered even in the case where the heat of the liquid droplets is taken away due to the change in the pressure of the fluid. Seen as beneficial. When the water droplets and the gas are mixed in the fluid mixing portion, heat is generated between the water droplets and the gas, or heat is generated between the water droplets and the mixing portion and the inner wall of the pipe or the like. Further, since the pressure reduction expansion occurs when the nozzle portion is accelerated and released to the atmosphere, the temperature of the gas is lowered. At this time, whether the temperature of the water droplets is lowered is determined by the latent heat of the gas. A gas that does not contain much latent heat, for example, when an inert gas or clean high-pressure air is mixed with pure water, the temperature of the gas is lowered to make it difficult to control the temperature. On the other hand, when the gas is water vapor, since the predetermined amount of latent heat is present, when the water is mixed with the relatively low temperature water droplets or when the inner wall of the pipe is taken away, the temperature of the gas can be easily lowered by the movement of heat. There is a tendency to easily control the temperature. However, if the latent heat of the water vapor is insufficient, a part of the water vapor is liquefied to generate droplets, which affects the shock wave generated on the surface of the object to be treated. Furthermore, when the multiphase fluid is finally accelerated in the throat of the nozzle, the temperature of the fluid is lowered in order to obtain the kinetic energy of the fluid, but the latent heat of the water vapor can be used to reduce the temperature of the fluid.

Overall structure of the object processing device

Fig. 1 is a general view of an object processing apparatus 100 according to an embodiment of the present invention. The apparatus 100 has a water vapor supply unit (A), a pure water supply unit (B), a water vapor fluid adjustment unit (C), a multi-phase fluid irradiation unit (D), and a wafer holding ‧ rotation ‧ Agency Department (E). Hereinafter, each part will be described in detail.

(A) Water Vapor Supply Department

The water vapor supply unit (A) comprises: a water supply pipe 111 for supplying pure water; heating to a predetermined temperature D1 (° C.) or more to generate water vapor, and controlling the amount of water vapor generated and adding water vapor. a steam generator 112 that is pressed to a predetermined value C1 (MP); a water vapor switching valve 113 that controls the supply of steam and the stop switch; a pressure gauge that measures the pressure of water vapor supplied from the steam generator 112 to the downstream a water vapor pressure regulating valve 115 for adjusting the steam supply pressure to a desired value; a heating steam generator and a saturated vapor humidity regulator 116 with a temperature control mechanism for adjusting the amount of minute droplets in the supplied water vapor; And a pressure relief valve 117 as a safety device.

(B) Pure Water Supply Department

The pure water supply unit (B) comprises: a water supply pipe 121 for supplying pure water; a heating portion 122 with a pure water temperature control mechanism for allowing pure water to have thermal energy; and stopping the supply of pure water and a pure water switching valve 123 re-supply; a pure water flow meter 124 for confirming the flow rate of pure water; and a pure water switching valve 125 for generating a fluid for stopping the supply and re-supplying of the downstream pure water for the 2 fluids .

(C) Water vapor fluid adjustment unit

The steam fluid adjusting unit (C) has a heating unit 131 with a steam fluid temperature control mechanism for adjusting the temperature of the steam fluid and the humidity of the saturated steam.

(D) Multiphase fluid irradiation unit

The multiphase fluid irradiation unit (D) includes an irradiation nozzle 141 that can move the multiphase fluid to the object in the front-rear and left-right directions (the X-axis nozzle scanning range or the Y-axis nozzle scanning range in FIG. 1); An elastic pipe 142 for smoothly moving the nozzle; a pressure gauge 143 for measuring the pressure immediately before the nozzle of the multi-phase fluid; and a gas-liquid mixing portion for introducing pure water in a manner of forming a water film on the wall surface with respect to the steam pipe 144; and an orifice 145 for smoothly introducing pure water into the gas piping. Here, the nozzle 141 is an ultra high speed nozzle. The "high-speed nozzle" is not particularly limited as long as it can accelerate the droplet to a speed equal to or higher than the sound speed. For example, a sonic nozzle can be cited. Figure 30 is a cross-sectional view showing the sonic nozzle and the mixing portion of the best mode. The shape of the sonic nozzle is not particularly limited, and has a tip widening nozzle structure in which the inside of the nozzle is rapidly reduced in diameter toward the nozzle outlet located below the drawing from the upstream side of the nozzle above the drawing, and is minimized. The position (throat) of the area A ₃ is a boundary, and the diameter is relatively gently expanded so that the fluid does not peel off from the inner wall, and the cross-sectional area at the nozzle outlet becomes A ₂ . The sectional area A ₃ of the throat is calculated by dividing the flow rate by the speed of sound. The sectional area A _{3 of the} throat is not particularly limited, and is, for example, 3.0 to 20.0 mm ² . Further, the expansion ratio (A ₃ /A ₂ ) is calculated by the equation expressed by the following mathematical formula 1.

[Math 1]

Here, K is the specific heat of the gas (constant pressure / constant volume specific heat), and P ₁ is the pressure of the throat of the nozzle, P ₂ of the pressure system nozzle outlet. The cross-sectional area A _{2 of the} nozzle outlet is obtained by the expansion ratio and the sectional area A _{3 of the} throat. Here, the sectional area A _{2 of the} nozzle outlet is not particularly limited, and is, for example, 7.0 to 28.0 mm ² . Further, the length of the nozzle is set in consideration of various parameters such as the material, roughness, and flow velocity (Reynolds number) of the nozzle, and an appropriate value can be set. Further, the degree of expansion is considered in consideration of various parameters such as viscosity, density, and flow rate, and an appropriate value can be set. The shape of the nozzle outlet is not particularly limited and may be circular. Further, the inner wall surface of the mixing portion and the inner wall surface of the nozzle are formed into a substantially continuous curved surface. The mixing portion may be joined as a cylindrical body upstream of the nozzle or formed in an upstream portion of the nozzle. When the mixing portion wall surface and the nozzle wall surface are joined, the joint portion is preferably formed by forming a water film on the side of the wall while the water film is formed by the mixing portion, and forming a water film on the nozzle wall surface. It is not particularly limited, and may be a joint having a pipe, etc., and it is preferable that the liquid is smoothly integrated into the body so as not to be a barrier to the liquid level. Further, the mixing unit 144 will be described in detail later.

(E) Wafer holding ‧ rotating ‧ upper and lower mechanism

Wafer holding ‧ rotation ‧ upper and lower mechanism portion (E) includes: a susceptor 151 capable of loading and holding an object (wafer); a rotary motor 152 for rotating the pedestal 151; and moving the pedestal 151 a wafer up-and-down driving mechanism 153 for adjusting a distance between the outlet of the nozzle 141 and the wafer in the vertical direction; a cooling water pipe 154 for supplying cooling water for cooling the object (wafer); and stopping and re-cooling the cooling water A switchable cooling water switching valve 155 is provided; a cooling water flow regulating valve 156 for adjusting the flow rate of the cooling water; and a cooling water flow meter 157 for measuring the flow rate of the cooling water.

The overall configuration of the object processing apparatus of the present preferred embodiment has been briefly described above. Next, the mixing unit 144 of the multiphase fluid irradiation unit (D) will be described in detail. The mixing portion 144 has a water introduction portion 144a (Fig. 30) partially open to the inner wall surface, and is provided on the upstream side of the nozzle, and water can be supplied from the mixing portion at an angle of 90 degrees or less with respect to the traveling direction of the water vapor. The wall is mixed with water vapor. Preferably, the mixing portion has a cylindrical shape, and the inner diameter of the cross section joined to the mixing portion nozzle is preferably the same as the inner diameter of the inlet of the nozzle.

Here, the second drawing is a detailed configuration diagram in the case where the mixing unit 144 is a multiphase fluid liquid mixing unit with a temperature control mechanism. It is important that the mixing portion 144 minimizes the occurrence of a mutual change phenomenon between the liquefaction of water vapor and the vaporization of water in the inner wall of the mixing portion. Therefore, as shown in Fig. 2, the mixing portion 144 is preferably constructed as follows.

1) For stable mixing, the directions of the respective fluids of the gas and the liquid are at an angle of less than 90 degrees in the mixing portion.

2) The diameter of the pipe of the liquid fluid or the orifice provided in the pipe is much smaller in the mixing portion than the cross-sectional area of the flow path of the gas fluid.

3) By installing a heater in the mixing portion, the temperature of the inner wall of the mixing portion is controlled to meet the following conditions. The temperature of the inner wall is not too large (±20% or less) from the saturation temperature of the liquid under the pressure in the mixing portion. Further, the temperature of the inner wall is not too large (±20% or less) from the saturation temperature of the gas under the pressure in the mixing portion. Further, as the time passes, the inner wall of the mixing portion approaches the saturation temperature of the fluid, so that it is not intended to be used until the state of the multiphase flow is stabilized, and under the condition that the heat retention of the mixing portion is sufficiently performed, The heating function of this heater can be removed.

In the apparatus for processing an object by using a multiphase fluid in which a droplet and a gas are mixed, the fluid mixing portion is at a normal temperature at the time of starting the device. Then, when there is a difference between the temperature and the temperature of the water vapor, temperature unevenness occurs inside the liquid mixing device, and as a result, a part of the vapor phase changes to become water droplets, and the pressure of the multiphase fluid is sent out. It becomes unstable, and it is difficult to stably supply a certain shock wave to the surface of the object to be processed, so it takes time until the device operates stably. That is, when the heater is provided to the multi-phase fluid adjusting portion, the fluid mixing portion can be set to the same temperature as the temperature of the water vapor from the start, so that it is less likely to cause a change in the gas-liquid phase in the mixing portion, and the device can A stable shock wave is applied to the object processing surface.

Principle of cavitation control (bubble collapse related parameters)

The cleaning device of the present preferred embodiment is characterized by adjusting the gas pressure, the water mixing flow rate in the multi-phase fluid, the gas temperature, the temperature of the mixed water, the shape of the nozzle, the distance from the nozzle outlet to the object, the temperature of the object, The relative movement time between the nozzle and the object, and the temperature of the control droplet, the flow rate of the droplet, the size of the droplet, the number of droplets, the temperature of the surface of the object to be treated, and the irradiation area of the multiphase fluid per unit time The function. Among the above parameters related to bubble collapse, the flow rate, temperature, and droplet density of the droplets are particularly important. By controlling the above parameters, the jet generated by the droplets and the shock wave caused by the collapse of the bubbles, and the impact of the chain reaction generated by the shock wave can be obtained on the surface of the object to be processed, and can be performed in cleaning or the like. Effective processing. The flow rate is responsible for the generation of shock waves caused by the collapse of the bubbles in the droplets during the collision of the droplets, while the temperature contributes to the generation of bubbles within the droplets. In addition, the higher the droplet density, the higher the probability of generating a shock wave. For example, if the number of droplets is zero, no shock wave due to collision of the droplets will occur. However, when the number of droplets becomes too dense, the speed of the multiphase fluid may decrease and the temperature may decrease to lower the probability of generation of shock waves. Here, the droplet density means the number of droplets per unit volume per unit time in the multiphase fluid, and the measuring instrument for accurately measuring the μ droplets of the high order moving order has not been developed yet, so The amount of pure water introduced into the multiphase fluid is substituted.

Cavitation phenomenon measurement

The system of the present invention is provided with a measuring means for measuring the degree of cavitation under such conditions after irradiating the multiphase flow to the object or the measurement sample under certain conditions. Here, according to the current technology, it is impossible to perform the peeling and cleaning process while monitoring the size of the cavitation phenomenon (shock wave) (the strength of the cavitation phenomenon) and the density (the number of occurrences per unit time per unit time). Therefore, the technique employed in the present system changes the parameters related to the generation of cavitation in a prior experiment, and performs program processing, and determines the size of the cavitation phenomenon from the following data obtained from the result.

(1) Measuring means for measuring the physical change of the physical change of the object or the sample for measurement by a quantitative method

‧ convexity and concavity of the metal surface when irradiating the multiphase fluid on the metal surface

‧Rejection area of the resist and the amount of residue when irradiated on the surface of the resist

‧Removal rate of foreign matter attached to the entire surface of the wafer

(2) Means of measuring the sound of the noise of the cavitation phenomenon

‧The size of the noise of the cavitation phenomenon perceived by the acoustic sensor

(3) A measure of visual change in measuring the visual change of an object or a measurement sample by a quantitative method

‧ Image data of the resist stripping process photographed by a high speed camera. For example, the data of the temperature of the multiphase fluid and the convexity and concavity of the metal surface irradiating the multiphase fluid are confirmed as shown in Fig. 9. In addition, the correlation between the resist stripping performance and each parameter is confirmed by most of the data accumulated in the past three years. The data in Figure 8 is one case. For example, if the discharge pressure from the nozzle of the multiphase fluid is increased, the resist peeling area is widened and the residue is also reduced. However, excessively increasing the discharge pressure may cause physical damage to the object, and the advantage of the device may be compromised by low pressure processing. Therefore, in the present apparatus, the maximum discharge pressure from the nozzle was set to 0.3 MPa. This also results in the possibility of not using special high pressure resistant parts, and it is easy and inexpensive to manufacture a safe device. When the type of the nozzle and the distance between the nozzle and the object are constant, the results are as shown in Figs. 21, 22, and 23. However, as described above, there is no indication that a specific unit of the size of the shock wave generated by the droplet colliding at a high speed is expressed as a relative value of no unit.

Further, in the conventional technique (for example, Patent Document 1), in addition to the point of using the ultrahigh-speed nozzle, a configuration which is not significantly different from the present embodiment in the apparatus is employed. However, in the conventional technique, the physical force of the so-called "shock wave" is not observed at all in the processing of the object. Therefore, the control of the shock wave generation is not performed on the object. Further, under the conditions of the prior art, the "cavitation phenomenon" occurs entirely in the nozzle having a tapered tip at the tip end, and the life of the generated shock wave is extremely short and disappears before reaching the object. Specifically, the flow rate is accelerated when the multiphase fluid flowing in the nozzle approaches the tip end of the nozzle. Then, as a result of the fact that the flow rate is increased to a reduced pressure state, the liquid causes a cavitation phenomenon to generate a shock wave. According to the "cavitation phenomenon" published by Kato Yoji and the bookstore, the collapse of hydrogen bubbles in the liquid shock wave tube lasts for 2 to 3 μsec. The 3 μ second movement time of the fluid with a flow rate of 400 m/sec is only 1.2 mm, and the bubble collapse phenomenon disappears from the nozzle throat to the nozzle outlet. Further, even if bubble collapse occurs at the nozzle outlet, it is difficult to structurally set the object distance to 1.2 mm or less. On the other hand, in the present invention, the nozzle is centered on the function of accelerating or expanding the irradiation area of the multiphase fluid. Moreover, the bubble collapse related parameters related to the occurrence of cavitation can be adjusted substantially in any place as long as the cavitation phenomenon on the object is focused, for example, any space of the fluid piping in front of the nozzle. The fluid mixing section is carried out. Specifically, it can be controlled at any position within the range of the arrow symbol shown by α in Fig. 1 (between the steam generator and the nozzle outlet). In the following, the main bubble collapse related parameters will be described in detail.

Prevent aluminum corrosion

The object cleaning method of this best form has the effect of preventing aluminum corrosion in addition to the above-mentioned impact force. Here, it is also possible to control the corrosion prevention by adjusting the gas temperature, the temperature of the mixed water, the shape of the nozzle, the distance from the nozzle outlet to the object, the temperature of the object, and the relative movement time between the nozzle and the object. effect. Among the above related parameters, in particular, the temperature at which the multiphase fluid reaches the object and the pH at which the multiphase fluid reaches the object are particularly important. By controlling the above parameters, a special protective film for preventing corrosion can be formed on the aluminum surface. In the following, the parameters related to aluminum corrosion prevention are detailed together with the main bubble collapse related parameters.

(1) Temperature of the fluid

The shock wave system is mainly caused by the cavitation phenomenon which occurs when the liquid droplet collides with the surface of the object to be treated and the collapse of the cavitation phenomenon. The cavitation phenomenon is a cavity generated when a part of a liquid such as water generates a low pressure portion, and the higher the temperature of the gas and the liquid, the more likely it is to be generated. In other words, the higher the temperature of the droplets, the more likely the bubbles in the water droplets are generated, and accordingly, the bubble collapse which is the basis of the shock wave which becomes a large energy source on the surface of the object to be processed occurs, for example, the processing method is utilized. When the resist film is removed, a relatively strong resist film and foreign matter can be removed. On the other hand, when the temperature of the multiphase fluid and the water droplets is set to a low level, the generation of the shock wave can be suppressed on the surface of the object to be processed, and the object having a weak strength can be cleaned. However, there is a limit in the height of the settable temperature due to the limitation of the heat resistance of the object. Further, when the distance from the object becomes long in a state where the temperature is too high, there is a possibility that the gas component in the droplet falls off and the bubble core is not easily generated, and the distance from the nozzle outlet to the object is about 2 to 30 mm. The distance is set to be negligible. Further, the temperature of the water vapor supplied into the nozzle is preferably from 50 to 120 ° C, more preferably from 80 to 115 ° C, still more preferably from 90 to 110 ° C. Further, the temperature of the water mixed with the aforementioned water vapor is preferably from 0 to 40 ° C, more preferably from 10 to 35 ° C, still more preferably from 20 to 30 ° C.

Here, in particular, the temperature at which the multiphase fluid reaches the object is preferably 50 ° C or higher, more preferably 80 ° C or higher, and more preferably 90 ° C or higher. Further, the measurement of the temperature of the multiphase fluid was carried out by the method described in the examples. By setting it in this range, the aluminum on the surface of the object forms a special film that achieves a corrosion prevention effect.

(2) the speed of the droplet

The higher the speed of the liquid droplets, the larger the impact when the liquid droplets collide with the surface of the object to be treated becomes larger, so that an internal pressure difference is likely to occur, and as a result, bubble collapse is likely to occur and cavitation occurs. That is, if the velocity of the droplet is set to a high level, a shock wave of a large energy is generated on the surface of the object to be processed, for example, when the treatment method is used for removal of the resist film, the joint can be removed. Strong resist film and foreign matter. On the other hand, if the speed of the liquid droplets is set to a low level, the generation of shock waves can be suppressed on the surface of the object to be processed, and the object having weak strength can be cleaned. Further, by increasing the speed of the droplets, the time during which the multiphase fluid is exposed to the air is shortened, so that it is difficult to introduce carbon dioxide in the atmosphere, and it is difficult to be acidic, so that the effect of preventing corrosion can be more appropriately exhibited. The velocity of the droplets is from 100 to 600 m/s, more desirably from 200 to 500 m/s, more preferably from 250 to 350 m/s. By setting the fluid velocity in this range, the impact force of the cavitation phenomenon can be obtained. Further, it is assumed that the velocity of the droplets substantially coincides with the velocity of the fluid, and is set to "flow rate" / "nozzle sectional area". Here, the flow rate is set to the steam flow rate (m ³ /s), and the nozzle sectional area is the cross-sectional area (m ² ) of the nozzle outlet.

(3) Other parameters

First, regarding the nozzle, an ultra-high speed nozzle is used as described above. By using this nozzle, the flow rate of the fluid is changed and the magnitude of the shock wave is also changed. In principle, it is easy to obtain a shock wave when a nozzle having a large flow velocity is used. Further, by using an ultrahigh-speed nozzle to irradiate a multiphase fluid containing water vapor and water droplets, a special action is observed by the relationship between the pressure of the water vapor and the speed and diameter of the water droplets. The water vapor pressure is not particularly limited as long as it is 0.05 to 0.25 MPa. In particular, when the water vapor pressure is 0.15 MPa or more, the multiphase flow system of water vapor and water droplets is different from the multiphase fluid of air and water droplets. action. Next, regarding the distance from the nozzle outlet to the object, the general accommodation value is in the range of 2 to 30 mm (optimal range 2 to 10 mm), preferably 5 mm or less, more preferably 3 mm or less, and still more preferably 2 mm. If the distance from the exit of the nozzle to the wafer is reduced, the resist stripping performance is improved as well, and when the optimum distance is too close, the peeling performance is lowered. On the contrary, it is desirable to suppress the peeling performance and the cleaning performance as long as it is far from the optimum distance. Furthermore, the closer the distance from the nozzle outlet to the object is, the more difficult it is to introduce carbon dioxide in the atmosphere, and it becomes difficult to be acidic.

Further, in order to obtain a particularly high impact force, it is important that the liquid droplets are covered by the water droplets when they collide with the object. Here, the flow rate of the water vapor, which is the mass flow rate of the water vapor, is preferably 0.083 to 1.0 kg/min, more preferably 0.025 to 0.75 kg/min, still more preferably 0.33 to 0.50 kg/min. Further, the gas-liquid mixture ratio (liquid/gas) is preferably 0.00018 to 0.01. The droplet diameter is preferably from 2 to 25 μm. When the droplet diameter is increased, the surface area is reduced, so that the amount of carbon dioxide introduced into the atmosphere is reduced, and it becomes difficult to be acidic. Further, the droplet diameter was measured by a PDA (Phase Doppler Anemometry) using a machine manufactured by TSI, and was measured at a position of 5 mm from the nozzle outlet unless otherwise specified. The cross-sectional area of the fluid flow/discharge port is preferably 0.5 to 32.0 kgcm ^-2 min ^-1 .

In order to form water into the water film on the wall surface and to mix the water into the multiphase fluid, for example, it is preferable to set the pressure applied to the water to such an extent that the water does not flow back by the pressure of the water vapor. The pressure applied to the water is not particularly limited. For example, it can be introduced by introducing a pressure equal to or higher than the introduction of the water vapor pressure and applying the water. More specifically, the pressure of water introduction preferably satisfies the following formula.

(water vapor pressure + 0.02 MPa) < (water introduction pressure) < (water vapor pressure + 1.0 MPa)

When the pressure of water introduction is too low, the water is introduced as a pulsating flow, and the characteristics of the fluid become unstable. In addition, when the pressure is too high, the water will scatter to the center of the nozzle diameter direction, and it is difficult to form the same water film, and it also hinders the acceleration of the vapor. Further, from the viewpoint of forming a water film on the wall surface, it is preferable not to pressurize the spray direction, and it is more preferable to supply it in the vertical direction against the passage direction of the water vapor.

The pH of the multiphase fluid reaching the object is preferably from 7.0 to 9.0, more desirably from 7.0 to 8.0, more preferably from 7.0 to 7.5. Since the aluminum on the surface of the object forms a special film by setting the pH in this range, the corrosion preventing effect of aluminum can be obtained. Further, the pH measurement method is a method described in accordance with the examples.

[Examples] Method for measuring temperature when multiphase fluid reaches an object

Fig. 31 is a schematic view showing an apparatus for measuring temperature when a multiphase fluid reaches an object. The thermocouple TH (aluminum chrome thermocouple JIS C1602) is attached to the crucible W having a diameter of 6 吋 and a thickness of 0.625 mm by using TA, and the distance between the fluid ejection outlet of the nozzle 141 and the object, and the water vapor pressure The conditions such as the flow rate of the pure water are set to the same value as that of the object processing, and the thermocouple is irradiated for 1 minute, and the temperature at the steady state is the temperature at which the multiphase fluid reaches the object.

Method for measuring pH of multiphase fluid when it reaches an object

Fig. 32 is a schematic view showing a device for measuring the pH of the multiphase fluid when it reaches the object. The discharge port of the nozzle 141 is connected to the cooling pipe C (for example, a Graham condenser) via the pipe P, and the agglomerated water is recovered to the container R, and the pH of the water is measured by the method of JIS Z8802. Further, the agglutination operation is performed without contacting the air.

First case

The multiphase fluid (the case where steam was used as a gas and the case where air was used) was irradiated on the aluminum surface for 10 minutes under the following conditions. The AFM (atomic force microscopy) photograph before and after the treatment is shown in Fig. 3. Figure 5 shows the surface roughness data. Further, in this example, the surface roughness was measured by the method of profile analysis attached to the AFM.

Vapor pressure: 0.2Mpa

Steam temperature: 130 ° C

Pure water flow: 300cc/min

Pure water temperature: 20 ° C

GAP: 5mm

Nozzle scan: fixed

Second case

Under the same conditions as in the first example, the multiphase fluid (in the case where steam was used as a gas and the case where air was used) was irradiated on the steel surface for 10 minutes. The AFM photographs before and after the treatment are shown in Fig. 4. Figure 6 shows the surface roughness data.

Third case

The vapor cleaning technique disclosed in Patent Document 1 utilizes the mechanical action of steam and the mechanical action of the jet to peel off the resist, so that the stripping of the resist requires a time in minutes. This technique also visualizes high-speed video in order to confirm whether it is the same mechanism. Fig. 7 is a view showing the lapse of time when the multi-phase fluid is irradiated under the same conditions as in the first example, and the i-line positive photoresist is peeled off from the lower portion of the quartz wafer, except that the nozzle scanning speed is 100 mm/sec. The situation of change. As shown in Fig. 7, the region where the resist is peeled off gradually widens and peels off rapidly and rapidly.

Fourth case

Except that the nozzle scanning speed was set to 40 mm/sec, the multi-phase fluid was irradiated against the germanium wafer implanted with high-concentration ions under the same conditions as in the first example, and the elapsed time of the i-line positive photoresist peeling was observed. The situation of sexual change. The results are shown in Fig. 8.

5th to 8th cases

The gas and temperature of the multiphase fluid were changed under the following conditions, and the multiphase fluid was irradiated against the aluminum surface for 10 minutes. The AFM photographs before and after the treatment are shown in Fig. 9. The data of the surface roughness is shown in Fig. 10. Further, the surface of the aluminum to be treated before the irradiation was Ra of 34.9 nm.

Gas pressure: 0.2Mpa

Liquid flow: 300cc/min

Gap: 10mm

As a result of irradiating a multiphase fluid composed of low temperature air (20 ° C) and low temperature pure water droplets (20 ° C), a surface having Ra of 30.5 nM was obtained. The AFM photograph of the surface is shown in Fig. 9(a), and the surface roughness data is shown in Fig. 10(a) (the fifth example). Next, as a result of irradiating a multiphase fluid composed of high-temperature air (130 ° C) and low-temperature pure water droplets (20 ° C), a surface having Ra of 96.4 nm was obtained. The AFM photograph of the surface is shown in Fig. 9(b), and the data of the surface roughness is shown in Fig. 10(b) (sixth example). Then, as a result of irradiating a multiphase fluid composed of high-temperature air (130 ° C) and high-temperature pure water droplets (60 ° C), a surface having an Ra of 86.3 nm was obtained. The AFM photograph of the surface is shown in Fig. 9(c), and the surface roughness data is shown in Fig. 10(c) (seventh example). The surface roughness of (c) is slightly smaller than (b), and the density of the rough portion is larger than (b), so it can be seen that (c) is more affected by the shock wave than (b). Further, as a result of irradiating a multiphase fluid composed of water vapor and low-temperature pure water droplets (20 ° C), a surface having Ra of 257 nm was obtained. The AFM photograph of the surface is shown in Fig. 9(d), and the surface roughness data is shown in Fig. 10(d) (8th example). As a result of the above, as the temperature rises, the shock wave becomes large, and in particular, when water vapor is used for the gas, it is clear that the maximum shock wave is applied to the surface to be treated.

9th to 10th cases

The Al alumite surface having an Ra of 348.8 nm was irradiated with changes in the gas and temperature of the multiphase fluid under the same conditions as in the fifth to eighth examples. As a result of irradiating a multiphase fluid composed of air at 20 ° C and pure water droplets at 20 ° C, a surface having Ra of 380 nm was obtained. The AFM photograph of the surface is shown in Fig. 11(a), and the surface roughness data is shown in Fig. 11(c) (ninth example). Next, as a result of irradiating a multiphase fluid composed of 130 ° C water vapor and 20 ° C pure water droplets, a surface having Ra of 440 nm was obtained. The AFM photograph of the surface is shown in Fig. 11(b), and the data of the surface roughness is shown in Fig. 11(d) (the tenth example).

11th case

The SUS surface having an Ra of 8.1 nm was irradiated with changes in the gas and temperature of the multiphase fluid under the same conditions as in the fifth to eighth examples. As a result of irradiating a multiphase fluid composed of water vapor at 130 ° C and pure water droplets at 20 ° C, a surface having an Ra of 19. g nm was obtained. The AFM photograph of the surface is shown in Fig. 12(a), and the surface roughness data is shown in Fig. 12(b) (Example 11).

12th case

The surface of the titanium having a Ra of 75.5 nm was irradiated with changes in the gas and temperature of the multiphase fluid under the same conditions as in the fifth to eighth examples. As a result of irradiating a multiphase fluid composed of water vapor at 130 ° C and pure water droplets at 20 ° C, a surface having a Ra of 98 nm was obtained. The AFM photograph of the surface is shown in Fig. 13(a), and the data of the surface roughness is shown in Fig. 13(b) (12th example). With titanium, interference fringes can be visually observed. It is also possible to form an oxide film on the surface.

13th case

The surface of the crucible having a Ra of 1.9 nm was irradiated with changes in the gas and temperature of the multiphase fluid under the same conditions as in the fifth to eighth examples. As a result of irradiating a multiphase fluid composed of water vapor at 130 ° C and pure water droplets at 20 ° C, a surface having Ra of 7.6 nm was obtained. The AFM photograph of the surface is shown in Fig. 14(a), and the surface roughness data is shown in Fig. 14(b) (13th example).

14th to 25th cases

In the 14th to 25th cases, it was examined whether there was a difference in the peeling under the resist coating conditions. The presence or absence of HMDS (hexamethyldioxane, hexamethyldisilazane) and the Bake temperature were changed to 90 ° C and 110 ° C, and the influence of the change in the condition was observed. The resulting surface profile may not depend on the results of the substrate processing HMDS. The experiment was carried out under the following conditions.

Use sample: I line resist

Irradiation time: visually observed peeling

Gas pressure: 0.2Mpa

Liquid flow: 300cc/min

Nozzle scan: fixed

Gap: 10mm

Fig. 15 (a) to (c) show that the resist film is applied without HMDS or Bake at 90 ° C, and the sample is irradiated under the above conditions, and the peeling boundary interface is treated by a microscope observation. 15 (d) to (f) are observed by AFM. Fig. 15(a) shows a case where a multiphase fluid composed of air at 29 °C and pure water at 20 °C is irradiated, and the surface is observed under a microscope, and Fig. 15(d) corresponds to an AFM photograph (fourth example). Fig. 15(b) shows the case where the surface is observed by a microscope after the multiphase fluid composed of air at 130 °C and pure water at 90 °C, and Fig. 15(e) corresponds to the AFM photograph (15th) example). Fig. 15(c) shows the case where the surface is observed by a microscope after irradiating a multiphase fluid composed of water vapor at 130 °C and pure water at 20 °C, and Fig. 15 (f) corresponds to an AFM photograph (16th example). .

Fig. 16 (a) to (c) show that the resist film is applied without HMDS and Bake at 110 ° C, and the sample is irradiated under the above conditions, and the peeling boundary interface is treated by microscopic observation, Fig. 16 (d) to (f) show the case of observation by AFM. Fig. 16(a) shows a case where a multiphase fluid composed of air at 20 °C and pure water at 20 °C is irradiated, and the surface is observed by a microscope, and Fig. 16(d) corresponds to an AFM photograph (17th example). . Fig. 16(b) shows a case where the surface is observed by a microscope after irradiating a multiphase fluid composed of air at 130 °C and pure water at 90 °C, and Fig. 16(e) is an AFM photograph (18th example). Fig. 16(c) shows a case where a multiphase fluid composed of water vapor at 130 °C and pure water at 20 °C is irradiated, and the surface is observed by a microscope, and Fig. 16(f) corresponds to an AFM photograph (19th example). .

Fig. 17 (a) to (c) show that the resist film is applied under the conditions of HMDS and Bake at 90 ° C, and after irradiating the sample under the above conditions, the peeling boundary interface is treated by a microscope observation, and the 17th Figures (d) to (f) show the case of observation by AFM. Fig. 17 (a) is a case where a multiphase fluid composed of 20 ° C air and 20 ° C pure water is irradiated, and the surface is observed by a microscope, and Fig. 17 (d) corresponds to an AFM photograph (20th example). . Fig. 17(b) shows a case where a multiphase fluid composed of air at 130 °C and pure water at 90 °C is irradiated, and the surface is observed with a microscope, and Fig. 17(e) corresponds to an AFM photograph (21st example). . Fig. 17 (c) shows a case where the surface of the multiphase fluid composed of water vapor at 130 ° C and pure water at 20 ° C is irradiated, and the surface is observed by a microscope, and Fig. 17 (f) corresponds to an AFM photograph (22nd example). ).

Fig. 18 (a) to (c) show that the resist film is applied under the conditions of HMDS and Bake at 110 ° C, and the sample is irradiated under the above conditions, and the boundary interface is peeled off by microscopic observation. Figures (d) to (f) are the cases observed by AFM. Fig. 18(a) shows the case where the surface is observed by a microscope after irradiating a multiphase fluid composed of 20 °C air and 20 °C pure water, and Fig. 18(d) corresponds to the AFM photograph (23rd example). . Fig. 18(b) shows the case where the multiphase fluid composed of air at 130 °C and pure water at 90 °C is irradiated, and the surface is observed by a microscope, and Fig. 18(e) corresponds to the AFM photograph (24th case) ). Fig. 18(c) shows the case where the surface is observed by a microscope after irradiating a multiphase fluid composed of water vapor at 130 °C and pure water at 20 °C, and Fig. 18(f) corresponds to the AFM photograph (25th case) ).

26th case

The relationship between the droplet diameter and the flow velocity is shown in Fig. 19. The water vapor pressure was set to be constant (0.2 MPa), and the flow rate of the droplets and the droplet diameter were measured at various pure water flow rates. The results are shown in Fig. 19. Indicates the relationship between the droplet velocity V‧ diameter d measured by PDA. Both V and d are close to the normal distribution, and the average values are about 280 m/s and about 10 μm, respectively.

27th case

Fig. 20 is a graph showing the results of v and d when the flow rate of pure water is q = 100 mL/min, and the vapor pressure p and the distance h from the nozzle are set as parameters. Furthermore, for comparison purposes, the results of the mixed jet of air and droplets are also indicated by dashed lines. As can be seen from the figure, the target droplet velocity is about 200 to 300 m/s, and the droplet diameter is about 10 μm.

28th case (relationship between gas pressure and droplet velocity)

Change the flow rate of water to 200 cc/min, and change the pressure of the gas to 0.05, 0.1, 0.2 MPa, and use a sonic nozzle to spray a multiphase fluid of water vapor and water, and a multiphase fluid of air and water, and utilize LDA (Laser Doppler Anemometry: Laser Doppler Flowmeter) measures the velocity of the droplet at a position 5, 10 mm from the discharge port (Fig. 33). Further, the measurement of LDA was carried out by using LDA manufactured by TSI Corporation until measurement of 10,000 droplets was obtained, and measurement was performed three times under each condition. When a multiphase fluid of water vapor and water was used, it was observed that the velocity of the droplet was faster at a position of 10 mm than at a position of 5 mm. In addition, in the case of a multiphase fluid of air and water, it can be seen that the higher the pressure of the air, the higher the tendency of the droplets to become higher. On the other hand, the case of water vapor and water is unknown, but it is observed that the higher the pressure of water vapor is, the higher the velocity of the droplet becomes higher and higher than the predetermined value. Under 0.2 MPa, the droplet velocity will be measured according to the measured value. Go low. However, speculate that this may be an error. Under other conditions, the measurement is less than 10 seconds, and the multiphase fluid of water vapor and water is only required to be measured at a water vapor pressure of 0.2 MPa for several minutes. Therefore, it can be speculated that most of the noise is observed under this condition.

Case 29 (relationship between gas pressure and droplet diameter)

The flow rate of water was set to 200 cc/min, and the pressure of the gas was changed to 0.05, 0.1, 0.2 MPa, and the sonic nozzle was used to spray the multiphase fluid of water vapor and water, and the multiphase fluid of air and water, and the PDA was used. The diameter of the droplet was measured at a position of 5, 10 mm from the discharge port (Fig. 34). In addition, the measurement of the PDA was measured until the data of 10,000 droplets was acquired, and the measurement was performed three times under each condition. In the case of a multiphase fluid of air and water, the velocity of the droplet hardly changes even if the pressure of the air changes. On the other hand, although the cause of water vapor and water is unknown, if the pressure of the water vapor is increased, the change in the diameter of the droplet is hardly observed until the predetermined value, and the diameter of the droplet is observed at 0.2 MPa. The phenomenon of rapid change. However, speculate that this may be an error. Under other conditions, the measurement is less than 10 seconds, and the multiphase fluid of water vapor and water is only required to be measured at a water vapor pressure of 0.2 MPa for several minutes. Therefore, it can be speculated that most of the noise is observed under this condition.

30th case (pressure wave in the nozzle)

The pure water flow rate was set to 100 cc/min under the conditions of a water vapor pressure of 0.1 and 0.2 MPa, and a quartz nozzle was used to spray a multiphase fluid of water vapor and water. In this way, the pressure wave is observed at the tip of the quartz nozzle. This is shown in Figure 35. Further, Fig. 35(a) shows the case of injection under the condition of 0.1 MPa, and Fig. 35(b) shows the case of the injection under the condition of 0.2 MPa. Further, for comparison, the pure water flow rate was set to 100 cc/min under the conditions of a gas pressure of 0.1 and 0.2 MPa, and a quartz nozzle was used to illuminate the multiphase fluid of air and water. However, no pressure waves were observed at the tip of the quartz nozzle. This is shown in Figure 36. Further, Fig. 36(a) shows the case of spraying under the condition of 0.1 MPa, and Fig. 36(b) shows the case of spraying under the condition of 0.2 MPa.

(First to 36th embodiments)

Using a cleaning device having the best form of the sonic nozzle (Fig. 30), a multiphase fluid of water vapor and water is sprayed onto the object under the following conditions, and the cleaning effect, physical damage, and corrosion resistance of the wiring are evaluated. Sex (Table 1 and Table 2). Further, in the case of the object, a silicon wafer having aluminum wiring was used, which was coated with an i-line negative photoresist (Tokyo Pharma THMRip 3300) to a thickness of 1 μm, and dried at 90 ° C for 120 minutes. And exposed at 365 nm for 20 seconds, and developed with TMAH ([N(CH ₃ ) ₄ ] ⁺ OH ^- ) at room temperature.

Comparative example

The first comparative example is when the fluid temperature is too low. The polymer was removed when the fluid temperature was too low, and the wiring was corroded after 10 days.

In the second comparative example and the third comparative example, the case where the droplet velocity is too slow is too fast. When the polymer is too slow, the polymer remains, and when it is too fast, the physical damage of the wiring can be seen.

The fourth comparative example and the fifth comparative example are cases where the pH is too low and the case is too high. When the pH is too low, no protective film is produced, and after 10 days, the wiring is corroded. When the pH is too high, corrosion of the wiring due to high pH occurs.

[Industry use and utilization]

The invention can be used for processing materials with high strength, materials with low strength, and various kinds of objects. For example, the removal of unused materials such as lenses, precision machined parts, and molded resin products such as semiconductor devices, liquid crystals, magnetic heads, magnetic disks, printed boards, and cameras, ‧ washing, polishing, etc., and the use of 矽The present invention can also be utilized in the field of fine structure of process technology, deburring in the field of molding processing, and the like. Moreover, the present invention is preferably used for the treatment of materials that are taboo chemicals. .

100. . . Object processing device

111. . . Water supply pipe

112. . . Vapor generator

113. . . Water vapor switching valve

114. . . pressure gauge

115. . . Water vapor pressure regulating valve

116. . . Heating steam generator with temperature control mechanism and saturated steam humidity regulator

117. . . Pressure relief valve

121. . . Water supply pipe

122. . . Heating unit with pure water temperature control mechanism

123. . . Pure water switching valve

124. . . Pure water flow meter

125. . . 2 pure water switching valve for fluid generation

131. . . Heating unit with water vapor fluid temperature control mechanism

141. . . Irradiation nozzle

142. . . Flexible piping

143. . . pressure gauge

144. . . Multiphase fluid gas-liquid mixing unit with temperature control function

145. . . Orifice

151. . . Can be loaded and pedestal

152. . . Rotary motor

153. . . Wafer up and down drive mechanism

154. . . Cooling water pipe

155. . . Cooling water switching valve

156. . . Cooling water flow adjustment valve

157. . . Cooling water flow meter

Fig. 1 is a view showing the overall configuration of a processing apparatus of the present preferred embodiment.

Fig. 2 is a schematic view showing a multiphase fluid gas-liquid mixing unit with a temperature control mechanism in the processing apparatus of the present preferred embodiment.

Fig. 3 is a view showing a surface observation AFM photograph of the aluminum surface after the irradiation of the multiphase fluid for 10 minutes in the first example.

Fig. 4 is a view showing a surface observation AFM photograph of the second example in which the multiphase fluid was irradiated on the steel surface for 10 minutes.

Fig. 5 is a view showing the surface roughness of the aluminum surface after the irradiation of the multiphase fluid for 10 minutes in the first example.

Fig. 6 is a view showing the data of the surface roughness of the steel surface after the irradiation of the multiphase fluid for 10 minutes in the second example.

Fig. 7 is a view showing the results of the process of peeling off the resist from the back side by a high-speed camera while irradiating the multi-phase fluid on the resist applied to the transparent wafer in the third example.

Figure 8 shows the multiphase after the injection of high concentration ions in the fourth example. A diagram of the resist stripping data due to fluid exposure.

Fig. 9 is a view showing the results of the fifth to eighth examples.

Fig. 10 is a view showing the results of the fifth to eighth examples.

Fig. 11 is a view showing the results of the ninth to tenth examples.

Fig. 12 is a view showing the results of the eleventh example.

Fig. 13 is a view showing the results of the twelfth example.

Fig. 14 is a view showing the results of the thirteenth example.

Fig. 15 (a) to (f) are diagrams showing the results of the fourteenth to sixteenth examples.

Fig. 16 (a) to (f) are diagrams showing the results of the seventeenth to nineteenth examples.

Fig. 17 (a) to (f) are diagrams showing the results of the 20th to 22nd examples.

Fig. 18 (a) to (f) are diagrams showing the results of the 23rd to 25th examples.

Fig. 19 is a view showing the results of the twenty-sixth example.

Fig. 20 is a view showing the results of the twenty-seventh example.

Fig. 21 is a view showing changes in the magnitude of shock waves caused by the difference in thermal energy of the multiphase fluid.

Fig. 22 is a view showing changes in the magnitude of the shock wave due to the difference in the velocity of the multiphase fluid.

Figure 23 is a graph showing the change in the magnitude of the shock wave due to the difference in density of the multiphase fluid.

Figure 24 is a diagram showing the mechanism of cavitation caused by ultrasonic waves.

Figure 25 is a diagram showing the mechanism of the cavitation phenomenon generated when a droplet collides.

Figure 26 is a diagram showing the mechanism of the cavitation phenomenon generated when a droplet collides.

Figure 27 is a diagram showing the mechanism of the cavitation phenomenon generated when a droplet collides.

Figure 28 is a diagram showing the mechanism of the cavitation phenomenon generated when a droplet collides.

Figure 29 is a diagram showing the mechanism of the mechanism of the cavitation phenomenon generated when a droplet collides.

Fig. 30 is a view showing the structure of a sonic nozzle and a mixing portion.

Figure 31 is a schematic view of a measuring device for the temperature of a multiphase fluid.

Figure 32 is a schematic view of a measuring device for the pH of a multiphase fluid.

Figure 33 is a graph showing the relationship between gas pressure and water droplet velocity.

Figure 34 is a graph showing the relationship between the gas pressure and the diameter of the water droplets.

Fig. 35 (a) and (b) are views showing a state of pressure waves generated in the British nozzle.

Fig. 36 (a) and (b) are views showing a state in which no pressure wave is generated in the quartz nozzle.

100. . . Object processing device

111. . . Water supply pipe

112. . . Vapor generator

113. . . Water vapor switching valve

114. . . pressure gauge

115. . . Water vapor pressure regulating valve

116. . . Heating steam generator with temperature control mechanism and saturated steam humidity regulator

117. . . Pressure relief valve

121. . . Water supply pipe

122. . . Heating unit with pure water temperature control mechanism

123. . . Pure water switching valve

124. . . Pure water flow meter

125. . . 2 pure water switching valve for fluid generation

131. . . Heating unit with water vapor fluid temperature control mechanism

141. . . Irradiation nozzle

142. . . Flexible piping

143. . . pressure gauge

144. . . Multiphase fluid gas-liquid mixing unit with temperature control function

145. . . Orifice

151. . . Can be loaded and pedestal

152. . . Rotary motor

153. . . Wafer up and down drive mechanism

154. . . Cooling water pipe

155. . . Cooling water switching valve

156. . . Cooling water flow adjustment valve

157. . . Cooling water flow meter

Claims (8)

A method for cleaning an object includes a method of cleaning an object by a step of passing a multiphase fluid containing a continuous phase of water vapor and a dispersed phase of water droplets generated by mixing a water vapor and water in a mixing portion through a nozzle. The mixing portion is provided on the upstream side of the nozzle, and has a water introduction portion that is partially open on the inner wall surface, and the nozzle has a throat that is reduced in diameter from the upstream side of the nozzle toward the nozzle outlet, and has a minimum sectional area. The ultra-high-speed nozzle having a structure in which the end portion of the mixing portion is formed to have a substantially continuous curved surface, and the inner wall surface of the mixing portion is formed to have a substantially continuous curved surface, in which the fluid is not peeled off from the inner wall surface of the nozzle. Water is mixed from the inner wall surface of the mixing portion to the water vapor flowing in the mixing portion, and water is moved along the inner wall surface of the mixing portion from the inner wall surface of the nozzle, and the plurality of nozzles are ejected from the outlet of the nozzle. Phase fluid. The object cleaning method according to the first aspect of the invention, wherein the mixing unit has a tubular shape. The object cleaning method according to the first aspect of the invention, wherein the speed of the water droplets is set in a range of 100 to 600 m/s. The object cleaning method according to claim 1, wherein the temperature at which the multiphase fluid reaches the object is 50° C. or higher, and the pH of the multiphase fluid reaching the object is in the range of 7 to 9. The object cleaning method according to claim 4, wherein the distance between the multiphase fluid ejection outlet and the object is 30 mm or less. The object cleaning method according to the first aspect of the invention, wherein the object is a semiconductor substrate having an aluminum material such as aluminum wiring on its surface. An object cleaning system is a system for cleaning an object by irradiating a multiphase fluid containing water vapor and water droplets through a nozzle, and has: a water vapor supply means for supplying water vapor; and a water supply means for supplying the liquid; The nozzle for illuminating the multiphase fluid is characterized in that the mixing portion is provided upstream of the nozzle, and has a water introduction portion that can mix water to the inner wall surface of the water vapor flowing through the inner wall surface, and the nozzle The structure has a structure in which the diameter is reduced from the upstream side of the nozzle toward the nozzle outlet, and the end portion of the nozzle having a minimum cross-sectional area is used as a boundary, and the fluid is not gradually peeled off from the inner wall surface of the nozzle. In the ultrahigh-speed nozzle, the inner wall surface of the mixing portion forms a substantially continuous curved surface with the inner wall surface of the nozzle, and water is mixed from the inner wall surface of the mixing portion to the water vapor flowing in the mixing portion, and the mixture is mixed from the foregoing The inner wall surface of the portion moves water along the inner wall surface of the nozzle, and the multiphase fluid is sprayed from the outlet of the nozzle. The object cleaning system of claim 7, wherein the mixing portion has a cylindrical shape.