Method and apparatus for the treatment of objects, in particular for the cleaning of semiconductor elements
The invention relates to the continuous cleaning of objects, in particular of semiconductor elements, using ultrasound, wherein the objects to be cleaned are arranged within a liquid. Furthermore, the present invention relates to an apparatus for carrying out the method according to the invention. A basic idea of the invention is that the surface of an object to be cleaned ( 2 ) in a tank ( 5 ) filled with liquid passes through at least one oscillation maximum that is emitted by at least one sound source ( 8 a ) being present in the tank ( 5 ). According to one embodiment, the sound source fields ( 8 ) that are positioned within the tank ( 5 ) are arranged inclined with respect to the transport direction ( 4 ).
1. Method for the sonic treatment and cleaning of objects in a tank ( 5 ) that is equipped with liquid ( 6 ) and at least one sound source field ( 8 ), wherein the objects ( 2 ) are continuously transported on a transportation device ( 3 ) through the tank ( 5 ) and over the at least one sound source field ( 8 ), wherein the at least one sound source field ( 8 ) comprises several oscillation sources tuned to emit sound ( 8 b ) in-phase into the liquid ( 6 ) to impinge on objects with its oscillation maximum, further wherein the at least one sound source field ( 8 ) is arranged:
I. inclined less than Lambda/2 with respect to the plane of the object to be cleaned ( 2 ), wherein Lambda designates the wavelength of the sound ( 8 b ) emitted; or
II. movable and parallel to the plane of the object to be cleaned ( 2 ), wherein the movement is carried out either vertically or vertically and parallel to the plane of the object to be cleaned ( 2 );
thereby ensuring that the sound ( 8 b ) impinges on the surface of the object ( 2 ) with at least one oscillation maximum.
2. Apparatus for the sonic treatment and cleaning of objects ( 2 ) comprising a tank ( 5 ) that is equipped with liquid ( 6 ), at least one sound source field ( 8 ), and a transportation device ( 3 ) for continuous transportation of the objects ( 2 ) through the tank ( 5 ) and over the at least one sound source field ( 8 ), wherein the at least one sound source field ( 8 ) comprises several oscillation sources tuned to emit sound ( 8 b ) in-phase into the liquid ( 6 ) to impinge on objects with its oscillation maximum, further wherein the at least one sound source field ( 8 ) is arranged:
I. inclined less than Lambda/2 with respect to the plane of the object to be cleaned ( 2 ), wherein Lambda designates the wavelength of the sound ( 8 b ) emitted; or
II. movable and parallel to the plane of the object to be cleaned ( 2 ), wherein the movement is carried out either vertically or vertically and parallel to the plane of the object to be cleaned ( 2 );
thereby ensuring that the sound ( 8 b ) impinges on the surface of an object ( 2 ) with at least one oscillation maximum.
3. Apparatus according to claim 2 , comprising a multitude of sound source fields ( 8 ) each comprising several oscillation sources, further wherein the multitude of sound source fields ( 8 ) are arranged sequentially one after another in transport direction ( 4 ).
4. Apparatus according to claim 3 , characterized in that the multitude of sound source fields ( 8 ) emit different frequencies.
5. Apparatus according to claim 4 , characterized in that the frequencies emitted by the multitude of sound source fields ( 8 ) are increasing in transport direction (arrow 4 ).
6. Apparatus according to claim 5 , characterized in that the transportation device ( 3 ) comprises transportation elements for loading of the objects ( 2 ), that extend perpendicular to the transport direction ( 4 ) and are arranged in a distance from each other.
7. Apparatus according to claim 3 , characterized in that the multitude of sound source fields ( 8 ) have the same inclination α with respect to the plane of the object to be cleaned.
8. Apparatus according to claim 3 , characterized in that the multitude of sound source fields ( 8 ) have different inclinations α with respect to the plane of the object to be cleaned.
9. Apparatus according to claim 2 , characterized in that the temperature of the liquid ( 6 ) is between 15° C. and 25° C.
10. Apparatus according to claim 9 , characterized in that the temperature of the liquid ( 6 ) within the tank is room temperature.
11. Apparatus according to claim 6 , characterized in that the transportation elements comprise transport rollers that, for transportation of the object to be cleaned ( 2 ) in the vicinity of the multitude of sound source fields ( 8 ), are, in comparison with the remainder of the transportation device ( 3 ), spaced further apart from each other.
12. Apparatus according to claim 6 , characterized in that the transportation elements comprise transport rollers as well as, at least partially, holding-down means.