Cleaning and liquid contact with solids – Apparatus – With plural means for supplying or applying different fluids...
Reexamination Certificate
1998-05-26
2001-06-19
Coe, Philip R. (Department: 1746)
Cleaning and liquid contact with solids
Apparatus
With plural means for supplying or applying different fluids...
C134S095300, C134S133000, C134S153000, C134S902000
Reexamination Certificate
active
06247479
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a washing/drying process apparatus and a washing/drying method for chemical-solution-washing, rinsing and drying a surface of a substrate such as a semiconductor wafer or a glass substrate for an LCD.
In a process of fabricating a semiconductor device, a washing/drying process apparatus is used in order to remove a contamination such as particles, organic substances or metal ions from the surface of the substrate. An example of the apparatus for washing and drying a semiconductor wafer is a single-wafer-type washing/drying process apparatus for processing wafers one by one within a cup. In the single-wafer-type washing/drying process apparatus, a wafer is rotated, while being held by a spin chuck, and a chemical solution is applied to the surface of the spinning wafer for chemical solution washing. Then, pure water is applied to the washed surface to rinse it. Finally, a dry N
2
gas is applied to dry the wafer surface.
In the conventional apparatus, a chemical solution nozzle, a rinse nozzle and a dry nozzle are provided around the cup. These nozzles are moved between the home position and use position by different drive mechanisms. In this conventional apparatus, a considerable time is needed for switching from the chemical solution nozzle to the rinse nozzle and from the rinse nozzle to the dry gas nozzle. Consequently, so-called a water mark occurs when liquid drops adhering to the surface of the wafer dry naturally. The water mark is a compound of H
2
SiO
3
produced by reaction between oxygen and H2O in the atmosphere and silicon or by precipitation of a very small amount of SiO
2
included in rinse liquid (pure water) on the surface of the silicon wafer. Such a water mark may remain on the wafer surface even after the dry process.
In addition, in the conventional apparatus, when a chemical solution is applied to the rotating wafer, liquid drops separated centrifugally from the wafer adhere to the inner wall of the cup. Repetition of chemical solution wash processes results in adhesion of a great amount of liquid drops on the inner wall of the cup. This may adversely affect the subsequent rinse process. If the chemical solution drops have dried on the inner wall of the cup and their constituent has precipitated, particles of the constituent may occur and contaminate the wafer.
In the conventional apparatus, after the chemical solution wash process, the waste liquid is recovered from the cup and it is reused after regeneration. In the conventional apparatus, a recovery/regeneration apparatus for recovering and regenerating the waste liquid is disposed as a unit separated from the chemical solution wash apparatus and at a separate location. As a result, the conventional apparatus occupies a large area within the clean room. In addition, the length of the waste liquid recovery circuit (recovery piping) and the regenerated chemical solution return circuit (return piping) increases considerably. Thus, such problems will arise as an increase in capacity of a chemical solution supply pump and a variation in temperature of chemical solution.
In the conventional apparatus, in a case where the bottom surface of the wafer is hydrophobic, a process liquid, which has been applied to the bottom surface of the wafer from a bottom-side nozzle, will naturally drop from the bottom surface of the wafer before spreading over the entire bottom surface. In the conventional process apparatus, therefore, the area on the bottom surface of the wafer, which can be effectively washed, is limited.
Furthermore, the bottom surface of the wafer is not uniformly covered with the liquid, and after the process liquid has naturally dropped from the bottom surface of the wafer, the bottom surface of the wafer comes in contact with outside air in the state in which it is wet to some degree. As a result, a great number of gas-liquid interfaces occur on the bottom surface of the wafer and particles will easily occur at the gas-liquid interfaces. Consequently, particles adhere to the bottom surface of the wafer while the wash process is being performed, and the efficiency of the wash process considerably deteriorates.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a small-sized, simple-structured washing/drying process apparatus and a washing/drying process method capable of washing, rinsing and drying a surface of a substrate with a high through-put without producing a water mark.
Another object of the invention is to provide a washing/drying process apparatus and a washing/drying process method capable of immediately washing away a chemical solution, etc. on an inner wall of a cup and decreasing the length of a waste liquid recovery circuit and a return circuit.
Still another object of the invention is to provide a washing/drying process apparatus and a washing/drying process method capable of uniformly processing a lower surface of a substrate.
A washing/drying process apparatus according to the invention comprises: a spin chuck for holding a substrate such that a surface thereof to be processed faces upward and for rotating the substrate; a process fluid supply mechanism for selectively supplying one or two or more of a plurality of kinds of process fluids to the surface to be processed of the substrate rotated by the spin chuck, the process fluid supply mechanism having a first nozzle with a discharge port for discharging a process fluid which is in a liquid phase under conditions of room temperature and atmospheric pressure, and a second nozzle with a discharge port for discharging fluid which is in a gas phase under conditions of room temperature and atmospheric pressure; a driving mechanism for simultaneously moving the first and second nozzles to a location above the substrate held by the spin chuck; and a controller for controlling operations of the process liquid supply mechanism and the driving mechanism.
It is preferable that the washing/drying process apparatus further comprises a nozzle assembly in which the first and second nozzles are integrated, the discharge port of the first nozzle and the discharge port of the second nozzle being adjacent to each other in the nozzle assembly. It is also preferable that the discharge port of the first nozzle and the discharge port of the second nozzle are arranged concentrical at a lower part of the nozzle assembly. It is preferable that the discharge port of the first nozzle and the discharge port of the second nozzle are arranged symmetrical at a lower part of the nozzle assembly. It is preferable that the first nozzle has a first discharge port for discharging a chemical solution for chemical washing and a second discharge port for discharging pure water for rinsing, and the second nozzle has a third discharge port for discharging isopropyl alcohol vapor for drying and a fourth discharge port for discharging a dry inert gas for drying. Thereby, the dry gas can be applied from the second nozzle immediately after the chemical solution and rinse liquid have been discharged to the substrate from the first nozzle. Thus, the wash/rinse process and the dry process can be successively performed, and no water mark is produced.
A washing/drying process apparatus according to the invention comprises: a cup having at an upper part thereof an opening for loading and unloading a substrate; a spin chuck for holding and rotating the substrate within the cup; a process fluid supply mechanism having a plurality of nozzles for discharging and supplying a process fluid to the substrate held by the spin chuck; and a relative elevation mechanism for relatively and vertically moving at least one of the cup and the spin chuck, thereby varying a positional relationship between the substrate on the spin chuck and the cup.
The cup has an over-hang portion projecting inward so as to surround the opening and receiving the process fluid dispersed from the rotating substrate. The rinse liquid as second process fluid is indirectly applied to the over-hang portion, and dry N
2
gas as second pr
Kamikawa Yuji
Taniyama Hiroki
Tsurusaki Kotaro
Coe Philip R.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tokyo Electron Limited
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