Cleaning and liquid contact with solids – Processes – For metallic – siliceous – or calcareous basework – including...
Reexamination Certificate
1999-07-02
2004-02-24
Gulakowski, Randy (Department: 1746)
Cleaning and liquid contact with solids
Processes
For metallic, siliceous, or calcareous basework, including...
C134S001000, C134S001300, C134S011000, C134S030000, C134S102100, C134S105000
Reexamination Certificate
active
06695926
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a treatment method of semiconductor wafers and the like and a treatment system for the same; more specifically, the present invention relates to a treatment method of semiconductor wafers and the like, comprising a series of cleaning processes including a chemical process for removing dust, organic residues and inorganic residues or the like from surfaces of solid objects such as semiconductor silicon wafer, liquid crystal board and masking board by using several types of cleaning chemicals and a subsequent final water rinsing process (rinsing process) for rinsing off the cleaning chemicals from the object surface by using rinsing pure water, and a drying process of removing the rinsing pure water attached on the object surface, namely attached water (water drops) after completion of the final water rinsing process of the cleaning process, wherein these processes are carried out step by step in a sealed container. More specifically, the present invention relates to the improvement of a vapor treatment method and a treatment system for the same, wherein the removal of the attached water on the surface of the object is carried out at a drying process of mixing substitution using an organic solvent comprising a material readily mixable with the attached water and having a lower surface tension, for example IPA. (isopropyl alcohol).
2. Description of the Background Art
A variety of processes have been developed and proposed, conventionally, as a vapor treatment method comprising a series of cleaning processes from a chemical process for removing dust, organic residues or inorganic residues from the surface of the object by using several types of cleaning chemicals to a final water rinsing process for rinsing off the chemicals from the surfaces of the objects by using rinsing pure water, and a drying process of removing the attached water on the surfaces of the objects through mixing substitution with the vapor of an organic solvent, for example IPA (isopropyl alcohol), wherein these processes are carried out in a sealed container.
For example, these processes have been known, as described in published gazettes such as Japanese Patent Laid-open No. Sho 62-136825 (referred to as former, hereinbelow) and Japanese Patent Laid-open No. Hei 7-130699 (referred to as latter, hereinbelow).
According to the former vapor treatment process, however, an organic solvent in vapor is supplied from the top of a container into the container while rinsing pure water is pushed downward, to push out the water from the bottom of the container on completion of a series of rinsing processes. In other words, a pressure required to continuously supply an organic solvent vapor and to push down rinsing pure water and discharge the water from the bottom side of the container should be loaded appropriately, until the rinsing pure water is totally pushed down and discharged outside of the container. Because the former requires a vast amount of an organic solvent should be fed into the container per one drying process (per one cycle process), therefore, the former is disadvantageous and uneconomical from the respect of the cost. Because the organic solvent vapor should be fed into the container under a pressure required to push out rinsing pure water in the container, a gas pressuring means such as pump is essential.
According to the latter vapor treatment method, on contrast, the feeding of an organic solvent vapor into a sealed chamber is initiated, simultaneously when a object is drawn up from pure water in a rinsing tank, into the sealed chamber which is enclosing the rinsing tank, after the final water rinsing process of the cleaning process is performed in the rinsing tank fed with rinsing pure water, thereby condensation of the organic solvent vapor occurs on the surface of the object and the attached water is substituted with the organic solvent. In other words, the supply of the organic solvent vapor into the sealed chamber should be continued, at least until the object is completely drawn up from the pure water and the inside of the large sealed chamber is filled with the organic solvent vapor. Thus, like the former, the latter requires a vast amount of an organic solvent to be continuously supplied per drying process (per one cycle process), so that the latter is also costly and uneconomical.
SUMMARY OF THE INVENTION
The present inventors have therefore made various investigations. Consequently, the inventors have focused their attention to the fact that a part of an organic solvent fed into such container is condensed on the water surface, thereby forming a mixture layer of an appropriate thickness on the water surface, starting from the surface of the object toward the water surface; and that the concentration of the organic solvent in the mixture layer is lower on the side in contact to the water surface than on the side in contact to the object surface, which leads to the gradient of surface tension, and causes a liquid current from the object surface to the water surface. Thus, the inventors have achieved the present invention.
It is a purpose of the present invention to provide a treatment method and a system for semiconductor wafers and the like, capable of prominently reducing the use of an organic solvent per drying process (per one cycle process) at the vapor drying process of using an organic solvent.
It is another purpose of the present invention to provide a treatment method and system for semiconductor wafers and the like and capable of effectively and securely removing attached water from the surface of the object through the gradient of surface tension in addition to the mixing substitution with the organic solvent.
A still further purpose will be apparent in the detailed description and the drawings below.
These purposes can be attained by the treatment method and system for semiconductor wafers and the like in accordance with the present invention.
The treatment method of the present invention for semiconductor wafers and the like is including a series of processes from a cleaning process of an object to a drying process thereof in a sealed container and comprising a process of feeding warm pure water into the container where a plurality of sheets of the object are transferred and placed vertically in parallel arrangement, after the final water rinsing process of the cleaning process is completed, a process of feeding an organic solvent in vapor or fog at least into the upper space procured upward the fluid surface of the warm pure water in the container, a process of continuously feeding inert gas from the upper side of the container while the warm pure water is discharged under aspiration from the bottom side of the container after the supply of the organic solvent is terminated, and a process of drying the object comprising continuously reducing the pressure inside the container under aspiration, wherein the drying process of the object should be carried out under controls and regulations so that the pressure reduction in the container might be maintained at a preset pressure reduction degree at least untill the process of discharging the warm pure water from the bottom side of the container is completed.
The treatment system described above is characterized in that the water temperature of the warm pure water during feeding into the container is within a range of 30 to 65° C.; the preset pressure reduction degree in the container is within a range of −350 mmHg to −50 mmHg until the completion of the discharge of the warm pure water under aspiration to the outside of the container; preferably, the water temperature of the warm pure water is within a range of 40 to 50° C.; the pressure reduction degree in the container is preset within a range of −300 mmHg to −150 mmHg. The treatment system described above is characterized particularly in that the water temperature of the warm pure water is 45° C. and the pressure reduction degree in the container is preset at −240
Koyanagi Tetsuo
Mitsumune Naofumi
Tange Koichi
Yamaguchi Hiroshi
Yokota Ichio
Darby & Darby
Gulakowski Randy
Ses Co., Ltd.
Winter Gentle E
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