Cleaning and liquid contact with solids – Apparatus – For work having hollows or passages
Reexamination Certificate
2000-02-15
2002-09-03
Markoff, Alexander (Department: 1746)
Cleaning and liquid contact with solids
Apparatus
For work having hollows or passages
C134S171000, C134S16600C, C134S902000
Reexamination Certificate
active
06443171
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to an exhaust apparatus for a treatment unit for electrical components, preferably wafers, and, in particular, an exhaust apparatus for a spray tool to clean electrical components, whereby the particles located in the treatment unit are removed by suction. The invention furthermore relates to a system for treating electrical components. Finally, the invention also relates to a process for the removal by suction and/or rinsing of particles from a treatment unit of such a system.
The semiconductor industry frequently uses chemical spray tools to remove organic and inorganic contaminants from the very small chip structures that today have structural widths of 0.20 &mgr;m. The wafers become contaminated, for example, during the treatment process, e.g., in the plasma etching process used to produce the microstructures or the like, where difficult-to-remove organic polymers are created. Furthermore, e.g. after photolithographic steps, the silicon wafers must be cleaned of coating residues, which may be accomplished by spray tools.
The spray tools generally contain a carrier for the wafers, which in turn is located within a sealed housing. The process chemicals or chemical mixtures required for cleaning are sprayed through spray nozzles from the top or from the side onto the wafer surface.
In addition to cleaning the wafer surfaces of organic and inorganic contaminants, the removal of particles, such as dust particles from the clean room, also plays an important role. With chip structure widths of less than 0.4 &mgr;m, which are found, for instance, in the 16 MB DRAM chip, particles with a diameter greater than 0.16 &mgr;m may result in component failure. To ensure that the treatment unit itself does not cause particle contamination requires monitoring for particles greater than 0.16 &mgr;m diameter and their removal from the treatment unit.
Monitoring is not possible in conventional exhaust apparatuses for this type of spray tool, or treatment unit in general, which is made of polypropylene. Randomly occurring particle contamination frequently causes high defect densities on wafers and, not least of all, wafer reject rates, and thus results in production down time of the spray tool.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an exhaust apparatus and method of operating an exhaust apparatus which overcome the above-mentioned disadvantages of the prior art devices and methods of this general type, in which comprehensive cleaning of the electrical components in the corresponding treatment units even if cleaning from particles as small as 0.16 &mgr;m in diameter is required, is ensured.
With the foregoing and other objects in view there is provided, in accordance with the invention, an exhaust apparatus for a treatment unit for treating electrical components including wafers, the exhaust apparatus removing by at least one of suction and rinsing, particles located in the treatment unit, the exhaust apparatus containing:
a main exhaust pipe having an outside pipe and an inside pipe with a number of nozzles formed therein;
a side pipe having an outside pipe, an inside pipe with a number of nozzles formed therein, a first end to be connected to the treatment unit, and a second end connected to the main exhaust pipe; and
a storage tank containing a cleaning fluid connected to the inside pipe of the main exhaust pipe and the inside pipe of the side pipe such that the cleaning fluid at least intermittently flows through the inside pipe of the main exhaust pipe and the inside pipe of the side pipe.
According to a first aspect of the invention, the object is attained in that the exhaust apparatus serves to remove particles located in the treatment unit by suction. According to the invention, the exhaust apparatus contains the main exhaust pipe that is provided with an outside pipe and an inside pipe, with the inside pipe having a number of nozzles, and the side pipe that connects the treatment unit with the main exhaust pipe and is provided with an outside pipe and an inside pipe, with the inside pipe having a number of nozzles. The inside pipes are connected with a source for cleaning fluid so that a cleaning fluid at least intermittently flows through the inside pipes.
The exhaust apparatus according to the invention permits monitoring and removal by suction of particles greater than or equal to 0.16 &mgr;m in diameter so that particle contamination of the treatment unit and the electrical components with the aforementioned disadvantages is prevented.
The cleaning fluid is injected into the main exhaust pipe and the side pipe through the nozzles of the inside pipes so that these pipes can be rinsed with the cleaning fluid. This prevents contamination of the electrical components with particles originating from the exhaust apparatus. The inside pipes are suitably connected with the source of the cleaning fluid, which is stored in a suitable tank, for example, by corresponding lines.
Rinsing or cleaning is advantageously conducted after completion of a treatment process in the treatment unit and will be described in further detail below.
Application of the exhaust apparatus according to the invention is not limited to specific treatment units. Rather, it may be used wherever electrical components are sprayed with materials and where such spray materials must be subsequently removed by suction. An advantageous example is the application of the exhaust apparatus in a spray tool for cleaning wafers.
According to the invention, the side pipe can have an outside pipe with a 90 mm diameter and/or an inside pipe with a 20 mm diameter. The invention is of course not limited to the above diameters.
In a further embodiment, the side pipe can be formed of two or more partial areas. The partial areas are advantageously aligned at an angle with respect to each other. The angled embodiment of the side pipe further reduces the risk of particles entering the treatment unit from the side pipe. The angled side pipe can be configured as one piece or several pieces. In the latter case, the individual partial areas are produced first and are then assembled into the side pipe.
The partial areas are preferably aligned with respect to each other at an angle of between 135° and 155°, preferably between 140° and 145°, particularly at an angle of 142° 30′.
According to the invention, at least one of the edge-side partial areas of the side pipe may be connected with an extension element. Using one or several of the extension elements makes it possible to take into account the structural conditions, including the different distances between the treatment unit and the main exhaust pipe. If an extension element is used, the inside pipe is preferably also extended so that the extension element can also be rinsed with the cleaning fluid.
In a further embodiment, the main pipe is provided with an inside pipe with a diameter of 25 mm. Here, too, the diameter can be varied as required.
The pressure of the gas phase within the main exhaust pipe is preferably set within a range of 2.03 cm (0.8 inches) to 4.3 cm (1.7 inches)/water column, preferably at 3.81 cm (1.5 inches)/water column.
The main exhaust pipe and the side pipe are preferably connected with each other at an angle of 25° to 40°, preferably 30°. This angled configuration is important for the exhaust apparatus according to the invention, since it further improves the cleaning effect and prevents particle contamination.
In a further embodiment, the main exhaust pipe is connected with an additional exhaust pipe, whereby the exhaust pipe is connected or connectable with a clean room. The additional exhaust pipe is used to draw in air for the suction process within the exhaust apparatus. Drawing air out of the clean room, which has the result that the air quality is that of clean room Class 1 or better, ensures that no particles can be diffused back into the exhaust apparatus through the exhaust pipe. Furthermore, intake of clean room air via the exhau
Saez Pierre-Louis
Schneider Germar
Greenberg Laurence A.
Infineon - Technologies AG
Locher Ralph E.
Markoff Alexander
Perrin Joseph
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