Measuring and testing – Liquid analysis or analysis of the suspension of solids in a...
Reexamination Certificate
1999-01-26
2001-10-02
Larkin, Daniel S. (Department: 2856)
Measuring and testing
Liquid analysis or analysis of the suspension of solids in a...
C073S061520, C073S061550, C073S863120, C073S031020, C422S082040
Reexamination Certificate
active
06295864
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a clean room environment analysis system and to an analysis method using same. More particularly, the present invention relates to a system for analyzing water-soluble contaminants present in the air of a clean room.
It is well known that the quality and yield of semiconductor devices are greatly affected by the ambient conditions under which they are manufactured. Accordingly, manufacturing processes for semiconductor devices are performed in cleanrooms having highly-purified environments in which various kinds of air contaminants, such as dust, microscopic organisms, ion particles, etc., must be eliminated to the greatest, practical degree possible. This is especially true for those clean room fabrication processes which form highly-sophisticated patterns on semiconductor devices. Unfortunately, in actual practice, the air in cleanrooms always contains some contaminants, and these contaminants create wafer defects. Thus, techniques for controlling air quality in cleanrooms have become increasingly important as semiconductor geometries have become increasingly small.
Water-soluble contaminants, such as ammonia, nitric acid compounds, sulfuric acid compounds and the like, are particularly troublesome. These water-soluble contaminants are generated when various semiconductor compounds, gases, or other contamination sources come into contact with moisture in the air. These contaminants typically have ionic bonds, and are thus easily attached to the surface of a semiconductor device under manufacture. Water-soluble contaminants, along with other contaminants, create a “haze” phenomenon over the surface of a semiconductor wafer. Haze causes deterioration in photoresist layers, and during diffusion processes may act as undesired dopants.
As a result of these problems, which are merely selected examples, various conventional analysis systems and methods for analyzing water-soluble contaminants found in clean room air have been developed in previous attempts to control water-soluble contaminants. One widely used method is the “Jar Test.” In the Jar test, a jar filled with deionized water is left in the clean room. Over time, particles are absorbed into the deionized water. Subsequently, the “contaminated” deionized water is analyzed to roughly determine the nature and content of clean room contaminants. Another conventional method is the “Impinger Method,” in which some portion of the clean room air is forcibly circulated and passed through deionized water. As with the Jar Test, the resulting contaminated water may be evaluated.
These conventional methods for capturing water soluble contaminants are simple and easily employed. Unfortunately, it takes a long time for sufficient contamination particles to be captured for evaluation. The length of time required to capture sufficient water-soluble contaminants in conventional methods creates evaluation inaccuracies. Further, contamination evaluation is done after-the-fact, rather than in real-time. This precludes the identification of transient clean room contamination phenomenon, the accurate development of short-term evaluation criteria, and the recognition of absolute contaminant concentration relationships with other factors such a time.
SUMMARY OF THE INVENTION
The present invention is directed to a clean room environment analysis system and method for using same which substantially overcomes one or more of the problems associated with conventional systems and methods. The present invention provides an analysis system and method for a clean room environment which reduces the time required to capture air-boume, water-soluble contaminants. Analysis efficiency and accuracy are improved. The present invention provides essentially real-time or “On-line” analysis capabilities. The present invention also provides an analysis system and method for a clean room environment which allows distinction between various kinds of contaminants, as well as absolute measurement of various water-soluble contaminant concentrations.
To achieve these and other advantages, the present invention provides an environment analysis system for a clean room comprising: a cooling unit condensing water having water-soluble contaminants therein from water vapor contained in an air sample extracted from the clean room, and an analyzing unit analyzing the condensed water received from the condensing unit. The cooling unit comprises; a condenser through which the air sample passes, such that water vapor from the air sample condenses within the condenser, cooling means for cooling the condenser, a vacuum pressure generator forcing the air sample through the condenser, a condensed water collector receiving the condensed water from the condenser, and a condensed water supplier supplying condensed water from the condensed water collector to the analyzing unit.
The condenser preferably comprises at least one condensing tube vertically installed such that the air sample is induced at a top of the condenser and travels downwardly from the top to be discharged at a bottom of the condenser, wherein the at least one condensing tube is installed to pass through the cooling means.
More particularly, the condenser comprises a plurality of parallel condensing tubes made from glass.
The cooling means comprises; a cooling tank containing a cooling fluid in contact with the condenser; and a cooler comprising a compressor, an expander, and means for defining a cooling cycle such that a cooling medium circulates between the compressor and the expander.
The cooling tank further comprises a front door assembly, such that when the front door assembly is opened, the condenser may be removed from the cooling tank. Further, the means for defining a cooling cycle comprises a controller driving the compressor, such that an inner wall temperature of the condenser maintains a temperature within a range of from 0° C. to 10° C.
The vacuum pressure generator comprises: an air suction pipe installed with one end extending into a bottom end of the at least one condensing tube, and a vacuum pump attached to another end of the air suction pipe drawing the air sample through the condensing tube. One end of the air suction pipe is inserted into the bottom end of the at least one condensing tube and is separated from the inner wall of the condensing tube. The vacuum pressure generator further comprises a mass flow controller connected to the air suction pipe and defining the volume of the air sample amount drawn through the condenser.
The condensed water collector comprises: a condensed water vessel having a funnel-shape installed beneath the condenser to capture condensed water from the condenser, and a condensed water pipe transporting condensed water collected in the condensed water vessel to the analyzing unit. Further, the condensed water collector comprises a valve installed in the condensed water pipe, and a controller selectively opening and closing the valves by application of a control signal.
In one aspect, the condensed water collector comprises: a plurality of condensed water vessels, each having a funnel-shape, and each being installed beneath a respective condensing tube to capture condensed water from the respective condensing tube, a condensed water pipe transporting condensed water collected in each of plurality of condensed water vessels to the analyzing unit, a controller; and a plurality of valves fitted into the condensed water pipe, wherein the controller selectively opens and closes each one of the plurality of valves, wherein each one of the plurality of valves is respectively associated with one of the plurality of condensing tubes, such that selective opening and closing of each one of the plurality of valves defines the transport of condensed water from the associated one of the plurality of condensing tubes to the analyzing unit. Each one of the plurality of valves is preferably a solenoid valve.
The condensed water supplier further comprises: an injector loop installed along the condensed water pipe, wherein the conde
Hwang Jung-sung
Kim Kwang-Young
Lee Soon-young
You Nam-hee
Cygan Michael
Larkin Daniel S.
Samsung Electronics Co,. Ltd.
LandOfFree
Analysis system and method for water-soluble contaminants in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Analysis system and method for water-soluble contaminants in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Analysis system and method for water-soluble contaminants in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2578976