Device for cleaning flat, practically planar small parts, in particular flat semiconductor substrates

(42) Start of patent term: 15. 2.1989 (45) Date of issue: 10.10.1989 (51) Int.Cl? : H01L 21/304 B088 5/02 (56) Documentation:

CH-PS 649725 DE-0S2724579 EP-A2-0158904 US-PS4027686 (73)

Patentee:

THALLNER ERICH DIPL.ING.

A-4780 SCHÄRDING, UPPER AUSTRIA (AT).

(54) DEVICE FOR CLEANING FLAT, PRACTICALLY LEVELS, IN PARTICULAR FLAT SEMI-FINISHED SUBSTRATES

QQ

AT 389 019 (57) In a device for cleaning flat, practically flat small parts, in particular flat semiconductor substrates, blowing nozzles (6) which are adjustable relative to the small parts are used for the production of below a steep, 90 ° ⁰ deviating angle of attack on the air to be cleaned surfaces impinging air jets arranged in one or more transverse rows to the relative adjustment direction. It is provided a passage gap (3) for the small parts and the Blasdüsenquerreihen (6, 7, 8) are provided in the vicinity of a gap opening with inclined to this gap opening nozzle axes, so that the air jets emitted by them (7, 8) on the Surface of the obstructed by the gap to be cleaned small parts. To avoid a suppression and vortex formation and the consequent deposition of impurities on already cleaned surface areas additional injection nozzles are provided for each Blasdüsenquerreihe (7, 8), which are directed from the respective transverse row at a shallow angle of attack into the interior of the gap.

<img file="AT389019B_D0001.tif" />

0® 0073J1S

No. 389019

The invention relates to a device for cleaning flat, practically flat small parts on one or both sides, in particular for cleaning flat semiconductor substrates and intermediates formed therefrom in the production of building blocks for microelectronics before processing steps or the introduction into clean rooms, with relative to the small parts adjustable blowing nozzles for the production of at a steep angle of attack on the surface to be cleaned or The air jets impinging on the opposite surfaces of the part to be cleaned, the nozzles are arranged for each surface to be cleaned in one or more transverse rows to the relative adjustment direction and their axes are employed to one side of the row in angles other than 90 °.

Such devices make it possible to clean flat small parts with the air jets of adhering particles, in particular dust particles, whereby these particles are brushed off by the air jets, so to speak. The air supplied to the tuyeres can be made dust-free by filtering them themselves. It is possible to provide suction devices which extract air and dust from the space in which the nozzles blow out. The arrangement is usually made so that the entire width of the parts to be cleaned is coated by the air jets, d. h "that the air jets form a closed air curtain. It is also possible to provide wide-jet nozzles or arrange the nozzles in two rows offset from one another. In the simplest case, the rows are straight, but also arrangements in oblique rows or rows lying on curved lines are possible. As mentioned, the impurities are blown off to the side at which the surface to be cleaned with the nozzle axes forms an obtuse angle.

Corresponding devices are not only used for the cleaning of semiconductor substrates, but also in many other applications, such as for cleaning photographic recording material in microfilming, but also in photoelectric recording devices in use. In any case, a gentle and thorough cleaning or It is to be considered that, for example, semiconductor substrates which are used in microelectronics already adhere individual ones to the substrate or to an exposure mask used for the production of the component by photographic means

Dust grains can make a whole microchip or a series of microchips unusable.

In the known arrangements occurs despite accurate alignment of the nozzles, through which a full coverage of the surfaces to be cleaned is ensured when passing through the air jets, repeatedly to impurities for which no sufficient Eiklärung has been found.

The problems shown are also in other known devices for cleaning corresponding

Kiemteile not solved From CH-PS 649 725 it is known to blow with a single wide jet nozzle at an angle to the surface to be cleaned under relative movement of the surface and nozzle. In order to ensure the detachment of firmly adhering contaminants, the air flow of the nozzle is pulsed and there is provided an ultrasonic source for generating vibrations of the part to be cleaned.

From EP-A-0 158 904 it is known to clean hollow bodies by means of blowing nozzles, which are arranged in groups with converging air jets and to suck excess air out of the hollow bodies from the space between the converging air jets. Such a device is not suitable for cleaning flat small parts.

From DE-OS 27 24 579 a wet cleaner for photographic recording material is known in which the two flat sides of the recording material cleaned successively by Hochdruckbesprühung with a wet cleaner, then dried by air jets and finally the cleaned side veischmutzungssicher supported while the other side of the cleaning is subjected.

It is known from US Pat. No. 4,027,686 to clean a semiconductor substrate to be exposed within the exposure set on the side to be exposed by means of spray nozzles and liquid detergent suction nozzles and then to dry it by blowing air through a blowing nozzle.

'The object of the invention is to provide a device of the type mentioned, in which the previously occurring impurities of the cleaned part or the cleaned surfaces are avoided.

The above object is achieved in that a plate of limited implementation gap is provided for the small parts that the Blasdüsenqucneihe or rows are provided in the gap in the vicinity of the one gap opening with nozzle axes inclined to the closer gap opening by the angle of attack, so that the air jets emitted by them are directed onto the support surface of the support displaced by the gap; the opposite slit wall or the air jets of a row of nozzles mounted there supporting small parts and that are provided to avoid a suppression and vortex formation for each Blasdüsenquerreihe additional injection nozzles, which are directed by the respective transverse row at a shallow angle of attack inside the gap.

The invention is based on the surprising finding that in the mentioned arrangement of blowing with their air jets acting blowing nozzles in the lying between the air jets from the nozzles of the Blasdüsenquerreihe and the part to be cleaned or support Keilraum on that side of the nozzle row at which the nozzle axes with the surface to be cleaned or their carriers include an acute angle, a suppression and vortex formation occurs, by which it previously contaminated to a suction

Air or sucked back previously blown dust particles comes. By directed into the Spaltinnere injection nozzles and the supply of air in these mentioned wedge space, the suppression and vortex formation is prevented or even produced an overpressure, if necessary, so that there is no renewed

-2Nr. 389019

Deposit of dust particles on already cleaned surfaces can come. As mentioned, in the embodiment according to the invention a one- or two-sided cleaning of the small parts is possible. It is also possible to clean the surfaces of an exposure mask or a substrate that face each other when shooting with a set of nozzles. The amount of air to be supplied via the additional injection nozzles depends on the size of the wedge space, the angle of attack of the blowing nozzles, the pressure of the air supplied to the blowing nozzles and the amount of air discharged at the blowing nozzles. In most cases, a smaller number of additional injection nozzles than blowing nozzles will be required and the injection nozzles may also have a smaller cross-section than the blowing nozzles or be charged with smaller amounts of air.

The tuyeres and the additional injection nozzles may be attached to a common nozzle bar. This design results in a simple construction, wherein the air jets emitted by the additional injection nozzles can be distributed in the space lying on the corresponding beam side to form an air cushion, so that prevail in the wedge space at each point equal air pressure conditions. Preferably, the axes of the additional injection nozzles are inclined at approximately right angles to the axes of the blowing nozzles, so that the air jets emitted by them can not disturb the jets of the blowing nozzles and the jets of air blowing nozzles and additional injection nozzles in the direction of the surface to be cleaned counteracting forces generate, so that unwanted displacements of the part to be cleaned can be avoided.

Further details of Eifindungsgegenstandes takes the following description of the drawing.

In the drawing, an apparatus according to the invention is illustrated in the diagram as an exemplary embodiment. 1 shows a lower part of a cleaning device in the diagram and FIG. 2 shows a cleaning device consisting of lower and upper part schematically in side view.

In the illustrated cleaning device include a plate-shaped lower part (1) and also a plate-shaped upper part (2) between them a passage gap (3) through which in the embodiment of FIG. 2 from left to right or vice versa an optionally held on a support device, flat small part is conveyed through. You could also hold the small part and the plates (1, 2) adjust in opposite directions, so that the top and bottom of the small part of the air jets of the cleaning nozzles to be described will be painted.

The lower part (1) and the upper part (2) each carry a nozzle bar (4, 5) which are the same design in the embodiment and have interconnected and with a common source of compressed gas blowing nozzles (6) in a transverse row. The bars (4, 5) are flat rectangular in cross section in the exemplary embodiment, with the axes of the nozzles (6) standing perpendicular to the free bar surface. As can be seen, the beams (4, 5) are inclined in the upper part (2) or the lower part (1) used, so that the nozzle axes are directed at an angle of attack of the flat top or bottom of the parts (1,2) against the opposite side of these parts and thus against the flat sides of a moving small part. The air jets (7, 8) emitted by the nozzles (6) complement each other to form a closed blown curtain. At the sides of the beams (4, 5) directed into the gap (3), additional injection nozzles (9) are provided which additionally supply filtered air to the gap space (3) and thus prevent the suppression and vortex formation in this space (3). The air jets emerging from the nozzles (9) were designated (10)