Patent Application
20070131254
The present invention relates to a washing apparatus which is used to remove organic matter from a specific material. Particularly, the present invention directs to a washing apparatus with bubbling reaction through ozone and a washing method of using such reaction.
Heterogeneous reaction systems widely exist in various industries, for instance, catalytic reaction systems and long-film processes for high level electronic components. To raise heterogeneous mass transfer efficiency in multiphase is important to develop technology related process. In a heterogeneous reaction system in which gas-liquid-solid phases coexist, because the reaction needs to be conducted through interfaces of the both gas-liquid and liquid-solid phases, the thickness of an interface diffusion layer and the replacing frequency in the reaction interface become a critical bottleneck to affect the reaction rate.
Conventional technology commonly uses certain of manipulations such as a mechanical stirring, an ultrasonic wave, or an ultrasonic vibration to compress the thickness of the interface and increase the mass transfer efficiency. However, in a heterogeneous reaction system that a liquid phase exists in a large proportion and a gas phase belongs to a hardly-soluble gas, a critical step affecting the reaction rate mainly depends on the mass transfer rate between gas-liquid interfaces. The mechanical stirring cannot effectively compress the interface, and thus a restricted effect on the mass transfer diffusion can be accomplished. Recently, there is also a new research that utilizes a centrifugal force generated by high-speed rotation to centrifugally remove a water layer from a surface of a solid which can compress the thickness of water film and replace a contact interface. Nevertheless, this method has restrictions on the shape, size and dimension of a material to be treated because it needs to consume a larger electrical energy, and in addition, the high-speed rotation operating for a long time may cause a concern about generating pollution of micro-particles.
At present, a method for controlling the interface diffusion layer in the heterogeneous system has not been published in the international research yet. Regarding a photoresist washed by aqueous ozone and its related equipment, the prior art describes the following technology.
These methods all needs to be conducted under conditions of a high-speed rotation, a high-temperature heating, an ultraviolet (UV) ray, or some additional oxidants, chemical solutions, etc. Especially, the operation of high-speed rotation has high restrictions on its applications because it has a great concern for a nanometer process. Specifically, the operation of high-speed rotation has strict requirements for size, shape, and symmetry of placement of a material to be treated and may generate pollution of micro-particles.
How to effectively use an ozone gas-liquid system for washing is a valuable technology worthy to think over.
According to the currently known technology, using sulfuric acid for washing is the oftenest used means which, however, has flaws in high-temperature (120° C.) process, a large amount of water consumption and discharging waste acid, and hard to treat a material containing a metal layer. In other words, the means deeply consumes resources and is not environmental protection.
The main objective of the present invention is to provide a washing apparatus with bubbling reaction and a washing method of using bubbling reaction that resolve the restrictions on the current technology. The present invention utilizes a concept of compression technology of an interface diffusion layer with bubbling which is applied to design a washing process of a reaction tank removing organic matter. Under operational conditions of saving water and energy without rotating the substrate in high-speed, the present invention can efficiently remove the organic matter from a substrate surface.
To accomplish the above objective, the present invention provides a washing apparatus with bubbling reaction and a washing method of using bubbling reaction, wherein the washing apparatus with bubbling reaction comprises a reaction tank to contain washing solution and simultaneously is installed with other working units for generating bubbles in the washing solution and for controlling the temperature of the washing solution and controlling the means of rotating a substrate during washing. Since the present invention can be manipulated under conditions of saving water and energy without rotating the substrate in high-speed, it can be carried out at ambient temperature and pressure without a concern about generating pollution of micro-particles and is highly flexible to the size of a material to be treated.
Moreover, the present invention can apply to remove a lithography photoresist in various industries such as semiconductor, thin film transistor-liquid crystal display (TFT-LCD), micro/nanometer precision machined mold and so on, as well as to a process of washing a surface of the other material. In the future, the present invention can also apply to disinfect medical equipments or wash a surface of nanometer material during its production.
To further illustrate the above objectives, structural characteristics and functions of the present invention, detailed descriptions are disclosed as follows by reference to accompanying drawings, in which
The present invention discloses a washing apparatus with bubbling reaction which uses a bubbling reaction to remove organic matter from the surface of a substrate. First, please refer to
The washing apparatus with bubbling reaction of the present invention comprises a reaction tank 10, a motion unit 20, a temperature-control system 30, a source 40 for supplying reaction liquid, a source 50 for supplying reaction gas, a pressure-control system 60, a bubble-generating means 70, and a source 80 for supplying washing solution. The reaction tank 10 is used to place a substrate 90 and provide a space for washing the substrate 90. The substrate 90 is placed on the motion unit 20, which lets the substrate 90 generate rotational displacement in the reaction tank 10 during washing. The source 50 for supplying reaction gas is used to supply the reaction tank 10 with the reaction gas, and the source 40 for supplying reaction liquid is used to supply the reaction liquid to the temperature-control system 30. After receiving the reaction liquid, the temperature-control system 30 controls the temperature of the reaction liquid and then supplies the reaction liquid at an appropriate temperature to the reaction tank 10.
The reaction liquid forms a horizontal plane in the reaction tank 10 and completely covers the bubble-generating means 70. The bubble-generating means 70 can be a pipe made from material capable against the erosion of ozone, on the pipe at least one exhaust outlet is installed to exhaust the gas or the means 70 can be made from a gas distributor disc. After receiving the reaction gas, the bubble-generating means 70 supplies the gas to the reaction liquid to generate bubbles 71. The pressure-control system 60 also connects with the reaction tank 10 and is used to control the pressure in the reaction tank 10 and, after the reaction is completed, extract the surplus reaction gas from the reaction tank 10. The washing procedure can then be carried out after the organic matter is successfully removed from the substrate 90. At this moment, a source 80 for supplying washing solution can provide the washing solution to wash the substrate 90. The washing procedure can be finished in the reaction tank 10 or accomplished in another washing tank by transferring the substrate 90 to another tank.
In order to attain a good effect on removal, the foregoing reaction gas can use ozone or a mixed gas containing ozone. The ozone can be generated by a high-voltage electric field or ultraviolet (UV) irradiation. When the reaction gas enters into the reaction tank 10, the concentration of the reaction gas is preferably 1% to 17%. The reaction liquid 81 can be selected from de-ionized water (DI-water), aqueous ozone, or an aqueous solution having an appropriate pH adjusted by HCl, H2SO4, NH4OH, and so on with a temperature of from room temperature to 80° C. The generated bubbles 71 may climb up along the substrate 90 which has already been fastened on the motion unit 20 by the fixed means 21. The motion unit 20 can generate rotational motion with the rotational rate ranging from 1 to 10 rpm to rotate the substrate 90. The motion unit 20 can be designed to rotate itself together with the substrate 90 or only to rotate the substrate 90.
Next, please refer to
Supposing a semiconductor wafer or a glass substrate is used as the substrate, when the substrate needs to be washed due to a photoresist or any organic contaminant during its production, the substrate is firstly placed into the reaction tank (Step 200). Subsequently, the reaction gas is supplied to form bubbles (Step 210) where the reaction gas needs to be supplied in appropriate concentration and flow rate and further delivered through the reaction liquid at an appropriate temperature to generate bubbles. The bubbling reaction is carried out afterward to remove the organic matter from the substrate (Step 220). At this moment, the bubbles may climb up along a surface of the substrate and remove the organic matter from the surface of the substrate. This procedure can be done by either a continuous reaction (Step 230) or a batch reaction (Step 240). After the reaction is completed, the remaining reaction gas is extracted and destroyed (Step 250). Then, the washing procedure is conducted; namely, the washing solution is used to wash the substrate on which surface the organic matter has been removed (Step 260). The washing procedure can be finished in the original reaction tank or accomplished in another washing tank by transferring the substrate to the washing tank. Finally, the completely washed substrate is taken out from the tank (Step 270) to finish the whole process. Now please refer to
In the reaction process of removing the organic matter, part of the substrate needs to be soaked in the reaction liquid. The height of the water level that the substrate soaks in the reaction liquid preferably occupies 5% to 80% of the diameter of the substrate. Meanwhile, the angle between the substrate and the plane of the reaction liquid is preferably in a range of from 5° to 90°. The exhaust outlet of the reaction gas needs to locate below the substrate and the reaction liquid in order to ensure generating the bubbles successfully. When Step 220 carries out, the substrate may further need rotational motion to ensure the effect on removing the organic matter. The rotational motion can set the rotational rate between 1 rpm and 10 rpm. The continuous reaction (Step 230) and the batch reaction (Step 240) can be optionally selected depending on situations, and the differences between these reactions are as follows.
In the final washing procedure, the washing solution has no special restriction on entering into the reaction tank and can be infused from the top or the bottom. The means of washing can be selected from soaking, showering, or spraying.
Moreover, the method of the present invention utilizes gaseous ozone to naturally form a bubble wall in liquid as a reaction interface in a gas-liquid-solid heterogeneous system. Without rotating the substrate in a high-speed, the bubbles are generated by a pneumatic means and climb up along a surface of a material to be washed. In a pull process when the bubbles climb up, the liquid-solid interface can be compressed to a minimal thickness and thus mass transfer efficiency in multiphase can be increased that can remove the organic contaminants effectively. The method of the present invention has advantages of saving water and energy, carrying out at ambient temperature and pressure without rotating the substrate in high-speed and without a concern about micro-particle pollution, and being flexible to the size and the type of material to be treated.
Although the present invention is exemplified by the above preferable embodiment, it does not intend to use to restrict the scope of the present invention. Person skilled in the art can make a certain modification and change without departing from the sprit and scope of the present invention. Therefore, it is necessary to define the scope of the present invention based on the claims described below.
| Number | Date | Country | Kind |
|---|---|---|---|
| 94144147 | Dec 2005 | TW | national |
