DE9013668U1 - Device for semiconductor technology - Google Patents

Description

JU &Iacgr;->&Oacgr;&Oacgr;&Ogr;\ JJ

PATENT ATTORNEY FRIENDLY TELEPHONE (0711) 25 26 62 &iacgr;.

SCHODERSTRASSE 1Ω FAX (0711)25 27 02 ^:

7&Ogr;&Ogr;0 STUTTGART 1 TELEX 7 252 252 RAIB D

TELEGRAMMS· ABELPAT STUTTGART "

POSTGIROL STUTTGART 744 OO - 7O8 |-\&Igr;&OHacgr;&Igr; ,,. _1/ &ngr; _u/ .. _|&rgr;

STUTTGART STATE GIRO CASH BANK 2915076 [_)&Igr;&EEgr;&Iacgr; ~ll\ICj2. HANo RAIBLE

AUTHORIZED REPRESENTATIVE AT THE EUROPEAN PATENT OFFICE EUROPEAN PATENT ATTORNEY

Hamatech GmbH Stuttgart, 28.09.1990

ATTORNEY FILE:

7130 Mühlacker 3

Device for semiconductor technology

The invention relates to a device for the treatment of semiconductor substrates, masks for semiconductor production, or the like, hereinafter referred to as substrates.

In semiconductor technology, the various substrates (wafers, masks, etc.) must undergo different processing steps, and this requires a large number of machines.

One object of the invention is therefore to create an improvement here.

According to the invention, this object is achieved in a device mentioned at the outset in that a process chamber is provided for receiving the substrate, that means for supplying at least one treatment liquid to the substrate are provided in the process chamber, and that a channel with an outlet is provided for discharging this treatment liquid after it has acted on the substrate and the mist formed by it, which channel is assigned a deflection element in such a way that the liquid and the mist from the process chamber are diverted through this channel and the liquid is at least partially separated in the channel.

This makes it very easy to separate the treatment liquid from the exhaust air and to dispose of the treatment liquid separately.

VTNR: 1&Ogr;6 941

Another solution to the problem is achieved in a device mentioned at the beginning in that a process chamber is provided for receiving the substrate, which has a wall that at least partially surrounds a receptacle for the substrate, that at least one receiving element provided with a recess for a nozzle is provided in this wall, and that a nozzle is arranged in the recess of this receiving element. In this way, the nozzle in question can be adjusted precisely to the desired location on the substrate after it has been installed, and an optimal cleaning effect is achieved.

A further solution to the problem is achieved in a device mentioned at the beginning in that a process chamber is provided to accommodate the substrate, which is not closed off by a door or the like above the substrate holder. The substrate cannot thus be contaminated by particles from the door during loading and unloading.

A further solution to the problem is achieved in a device as mentioned above in that a process chamber is provided to accommodate the substrate, and that the process chamber is in turn arranged in a housing designed as a collection container for the liquid mist coming from the process chamber. A long service life is thus achieved, since the collection container and process chamber can be made of a chemical-resistant plastic and the previously usual large number of hoses is largely eliminated.

A further solution to the problem is achieved in a device mentioned at the beginning in that a process chamber is provided for receiving the substrate, that an acid spray device is provided in this process chamber, and that this acid spray device is associated with a displacement device which

Moving the acid spray device within the process chamber is possible. Acid treatment can be carried out in the process chamber and then other processes can be carried out in the process chamber by moving the acid spray device to the edge of the process chamber, e.g. rinsing with deionized water, drying, etc. This enables several process steps to be carried out within the same process chamber.

A further solution to the problem is achieved in a device mentioned at the beginning in that a process chamber is provided to accommodate the substrate, to which a plurality of different treatment liquids, e.g. acids, alkalis, organic solvents or water, can be fed for treating the substrate, in particular at different times, and that these liquids can be fed to a drain valve after their effect on the substrate, which can be switched to one of several drains depending on the type of treatment liquid. Only a single, common line is therefore required for the treatment liquids up to the drain valve, which can be easily replaced after wear, and the treatment liquids are then separated at the drain valve, which makes their disposal much easier.

Further details and advantageous developments of the invention emerge from the embodiments described below and shown in the drawing, as well as from the various claims. It shows:

Fig. 1 is a three-dimensional representation of an inventive device and its process chamber, with the door of the process chamber in its open position,

Fig. 2 is a representation similar to Fig. 1, but with the door of the process chamber in its closed position,

Fig. 3 a highly schematic representation of a part

the process chamber and the door, which shows the cross-sectional shape of the door and its position when opened,

Fig. 4 is a view of the device, seen along the lines IV-IV of Fig. 5 or Fig. 9, wherein Fig.

4 shows the device in a partially assembled state, e.g. without the clamping device for the substrate to be treated, without the motor for driving the clamping device,

Fig. 5 is a section taken along the line V-V of Fig. 4, but in contrast to Fig. 4, the motor for driving the clamping device and the parts associated with it are shown in order to better illustrate the flow in this area; Fig. 5 is shown on a larger scale than Fig. 4,

Fig. 6 is a plan view of a typical vacuum-operated substrate clamping device,

Fig. 7 is a section through the upper section of the process chamber, seen along the line VII-VII of Fig. 4,

Fig. 8 is a top plan view of the process chamber, seen along arrow VIII of Fig. 7; the clamping device is not shown in Fig. 8; the scale of Figures 7 and 8 is larger than that of Figure 4 or Figure 5 in order to better show details,

Fig. 9 is a partially sectioned front view of the process chamber, seen in the direction of arrow IX of Fig. 4; Fig. 9 is shown on a larger scale than Fig. 4,

Fig. 10 is a representation of an angle-adjustable spray nozzle as used in the middle area of the process chamber; Fig. 10 shows three possible positions of this nozzle to illustrate the adjustability; the spray nozzle is shown in the installed state,

Fig. 11 is a partially sectioned, three-dimensional representation of a device according to the invention, which is here provided with an adjustable device for injecting treatment media,

Fig. 12 is a partially sectioned, three-dimensional representation of a device according to the invention, which schematically shows the course of the flows within the device when it is in operation,

Fig. 13 a three-dimensional representation of a drain valve with three different rotational positions, corresponding to three different process liquids that are to be disposed of separately,

Fig. 14 is a longitudinal section through the drain valve of Fig. 13, seen along the line XIV - XIV of Fig. 16,

Fig. 15 is a developed (stretched) section through the stationary base plate of the drain valve, seen along the line XV-XV of Fig. 16,

Fig. 16 is a plan view of the stationary base plate of the drain valve, seen in the direction of arrow XVI of Fig. 15, and

Fig. 17 is a diagram of a preferred microprocessor control of the device.

Fig. 1 shows a device 10 according to the invention, the essential part of which is a process chamber 11. In addition to this process chamber 11 and the associated closed container 12 located underneath it, which receives the vapors flowing out of the process chamber, the device 10 also contains storage spaces for treatment liquids, a control panel 14 with a programmable microprocessor control (Fig. 17) and corresponding display instruments and input devices (not shown), as well as further devices depending on the application.

·

Additional devices, one of which is shown in Fig. 11. These additional devices represent options that can be purchased additionally by the customer depending on the use of the device 10. The device according to the invention thus allows modular expansion according to the needs of the user.

In the process chamber 11 there is a clamping device 15, also called a chuck, and a substrate 16 to be treated is attached to this, e.g. by suction with a vacuum. By means of a continuously variable motor 17 shown in Fig. 5, the chuck 15 - as well as the substrate 16 located on it - can be driven at a speed which is, for example, between zero and 5,000 rpm and which can be controlled by the microprocessor mentioned above.

The substrate 16 can be, for example, chrome masks or chrome oxide masks or iron oxide masks for semiconductor production, wafers, or other special substrates, e.g.

are to be cleaned, etched or developed in this device.

Depending on the configuration, the following steps are carried out in the process chamber 11:

Cleaning with acid: H2O2/H2SO4 for chrome masks; HNO3 for iron oxide masks; cleaning with solvents, e.g. with ketones or with alcohol; cleaning with a brush (optional equipment); high-pressure cleaning (optional equipment); resist stripping with subsequent cleaning; etching; developing. Other applications are of course not excluded.

In particular, several of the aforementioned steps can be carried out one after the other in the process chamber 11, without the substrate 16 having to be removed from the process chamber, and in practice this represents a great saving of labor. The device according to the invention

■MT « & * * ■■ ■''■'

contains a variety of safety features that ensure that even in such successive process steps, that no safety-threatening moments arise.

This is done in particular by mutually locking process steps and by separating them from one another in time by rinsing them with deionized water.

The process chamber 11 forms in its lower section 21 (Fig. 5) a kind of pot with a continuous, cylindrical wall 21', which thus radially surrounds the chuck 15 and the substrate 16. This section 21 can also be referred to as a process pot 21. The wall 21' merges at the bottom on its inside into a circular ring-shaped part 22 which is tightly connected to it and which forms a channel 23 which has a gradient from right to left in Fig. 5, so that liquid flows in it to an outlet 24 and from there via a line 25 (Fig. 12) to a drain valve 26 (Figs. 12 to 16). Depending on the type of treatment liquid used, it is directed by means of the drain valve 26 to one of three drain lines A, B and C, of which, for example, line A is intended for water, line B for acids and line C for organic solvents. Appropriate receiving containers can be connected to these lines A, B and C respectively.

The drain valve 26 is locked by the electronic control (Fig. 17) to the type of treatment of the substrate 16: If this is to be treated with acid, the acid supply is blocked until the line 25 is connected to the line B by the drain valve 26. The same applies analogously to organic solvents: Their supply to the substrate 16 can only be switched on when the line 25 is connected to the line C by the drain valve 26.

By separating the drains only at the outlet of the device 10, it is possible to make the installation inside the device 10 extremely simple and clear.

and to greatly reduce the susceptibility to errors. In addition, repairs are very easy, since the drain valve 26 is preferably arranged on a wall, here the rear wall 28, of the device, see Fig. 12, and can therefore be very easily replaced or repaired from there.

Above the pot-like section 21, which in this embodiment represents approximately one third of the total height of the process chamber

11, the process chamber 11 has a vertical opening 30 on its side facing the control panel 14, which, when not closed, allows free lateral access to the substrate 16 or the chuck 15. This opening 30 is laterally delimited by two mutually parallel vertical boundary walls 31 and 32, the front edges 31' and 32" of which facing the control panel 14 preferably run vertically here and interact with the complementary side elements 33 and 34 of a door 35, as shown in Fig.

3 shows this particularly well in a schematic representation.

These side elements 33 and 34 of the door 35 each have a U-shaped cross-section, which encloses the associated boundary wall 31 or 32 in the manner of a labyrinth seal and thus ensures good sealing.

Fig. 1 shows the door 35 in its open state, in which it is separated by a gap complementary to it.

37 down and in the closed container

12, which is shown in Fig. 3 by dashed lines

38 is indicated. The gap 37 is formed in a worktop 40, which closes the closed container 12 at the top and is firmly connected to it, e.g.

by plastic welding, and in which the process chamber 11 is fastened, e.g. by welding, as shown in Fig. 5. The plan shape of the closed container 12 is shown in Fig. 4, where it is shown with dashed lines. This plan extends to the rear wall 28 of the device 11. The rear wall of the closed container 12 is provided there with an outlet nozzle

42 (Fig. 12), which is not shown in Fig. 4. - The closed container 12 has a horizontal bottom. This can be slightly inclined towards a drain, which drain is not shown in the drawing.

It is considered an important feature of the invention that the door 35 is located within the outline of the closed container 12 and that it is immersed in the container when opened. This is because during the treatment of the substrate 16, vapors from the treatment agent, e.g.

of acids, also on the inside of the door 35, which is then in its closed state (cf. Fig. 2), and the liquid from the door 35 then simply flows through the gap 37 into the closed container 12 and is subsequently disposed of from there.

The parts of the device 10 that come into contact with the treatment liquid are preferably made of natural polypropylene and, as far as possible, in one piece, either by machining the parts or by welding them together. This produces a compact, liquid-tight unit that can be inserted into or removed from the housing of the device 11 as a whole. This unit essentially consists of the worktop 40, the process chamber 11 fixed therein, and the closed container 12 that is welded to the worktop 40 at the bottom. In practice, this is all a large work piece that has to be carried by two people and that could be compared to a ship's hull, namely the container 12, with an oversized chimney, namely the process chamber 11, with the worktop 40 representing the deck.

Fig. 2 shows the door 35 in the closed state, in which it closes the side opening of the process chamber 11.

The process chamber 11 remains open at the top. During operation, clean air is constantly supplied from above. The open state at the top has the advantage that

■:■ .!&igr;·& ■** ^Jt

When a door is opened or closed, dirt particles fall onto the - just cleaned - substrate 16 in the process chamber 11 and contaminate this substrate again. If the door 35 moves vertically outside the area of the substrate 16, such contamination is prevented, especially since the air flow coming from above flows out of the side opening 30 when the door 35 is open, and carries dirt particles away to the outside.

A self-locking linear drive 45, which is arranged in the form of a column 46 next to the side wall 31, is used to operate the door 35. Its drive motor 47 and its reduction gear 48 are located below the worktop 40 and outside the closed housing 12. In the column 46 there is a spindle - not shown - which drives the door 35 via a driver 49.

The advantage here is that in the event of a power failure, the motor 47 and thus the spindle in the column 46 stops and the door is held in the position it was in when the power failed. Since internal locks ensure that a process in the process chamber 11 can only take place if the door 35 is closed, this ensures that in the event of a power failure during the course of a process, the door 35 always remains closed. - In Fig. 3, the linear drive 45 is not shown for reasons of clarity. In Fig. 1, the housing 12 is shown cut open on its front to show the position of the door 35 in its open state.

Fig. 12 shows the design of a chuck

15. This has, as also shown in Fig. 6 in plan view, a carrier ring 51 held by radial spokes 50, on whose four upwardly projecting pins 52 the substrate 16 is centered by vertical pins 53 and is held by vacuum by means of suction holes 54.

There are large openings between the spokes 50

55, through which the substrate 16 can also be processed from below if necessary. Naturally, the chuck 15 according to Fig. 6 is only one of many possibilities. A large number of designs of such chucks are known in the semiconductor industry. The chuck 15 according to Fig. 6, however, has a very advantageous structure; it is specially designed for large substrates, e.g. in the format 5 x 5 inches. For smaller substrates, correspondingly smaller chucks are used, as the person skilled in the art knows.

As Fig. 5 shows only schematically, the chuck 15 is attached to the shaft 57 of the electric motor 17. The latter, a brushless DC motor, is located within its own protective housing 58 in the form of a tube made of polypropylene, which is separated by an annular gap 59 from a tube 62 made of polypropylene, the latter being attached to the inside of the annular part 22 and projecting beyond it with its upper edge 62', as Fig. 5 clearly shows. The annular part 22 is expediently welded tightly by plastic welding to both the wall 21' of the process pot 21 and to the tube 62, as shown in Fig. 5.

The tube 58 (for the motor 17) is firmly connected to the tube 62 by radial pins 64 and is held in the latter. It is tightly closed at the bottom by a base 65, and also on its top by a cover 66 with a flange 67 that projects laterally over the tube 58. The shaft-side flange 68 of the motor 17 is in turn attached to the cover 66 (in a manner not shown).

Since process fluid from the process chamber 11 could penetrate into the motor 17 during operation, the pipe 58 is then connected to the motor 17 via a connection opening 70 and a line 71 (Fig.

12) is flooded with pure nitrogen, which is then discharged via a connection opening 72. Since this nitrogen is supplied under excess pressure, it may escape upwards via the bearings of the motor 17 and also flood the process pot 21.

The pipe 62 is slanted at the bottom, i.e. it is cut off at an angle alpha of e.g. 10°, so that the annular gap 59 in Fig. 5 is shorter on the right-hand side than on the left-hand side and increases continuously between them. Accordingly, the flow resistance is low on the right and increases towards the left. The same effect could also be achieved by arranging the pipe 58 eccentrically in the pipe 62. The reason for this measure is that the suction nozzle 42 of the closed housing 12 forces an asymmetrical flow in it, as is clearly shown in Fig. 12. Because the annular gap 59 on the side of the suction nozzle 42, which is to be imagined further to the left in Fig. 5, is longer than on the right-hand side, this asymmetrical flow is somewhat compensated and a largely uniform, laminar and vortex-free air flow is achieved in the process chamber 11.

The cover 66 is provided in its central region with an upwardly projecting collar 74, within which is located the corresponding flange section of the chuck 15. A tubular section 75 of a part 76 is pushed onto the outside of this collar 74, which extends from this section 75 in the manner of a round roof or hood with a slight incline radially outwards and downwards and is provided on its outer edge with a downwardly projecting section 77 which projects into the annular groove 23 but maintains a minimum distance from the bottom thereof.

As can be clearly seen from Fig. 5 and is shown by two flow threads 80 and 80', a liquid mist from the process chamber 11 passes along the outside of the part 76 into the channel 23 and flows through it, whereby the liquid mist is deflected by almost 180° and releases about 90% of its moisture, which is then disposed of via the line 25 as described. The rest passes further over the edge 62' into the annular gap 59 and from there into the closed container 12, from where it is discharged via the suction opening 42 (Fig.

12), e.g. via the factory's extraction system.

As Fig. 12 clearly shows, there are several deflecting bodies 82 in the suction opening 42, and these cause a further separation of liquid, which is drained off via a drain (not shown). This also applies to liquid that collects at the bottom of the closed container 12.

Nozzles 84 may be mounted on the top of the part 76, only one of which is shown in Fig. 5 and which serve to treat the back of the substrate 16. (In Fig. 5, the substrate 16 is not shown.)

Above the chuck 15, three support elements 85 are welded to the wall 21', of which only two are shown in Fig. 5. A screen 86 is placed on these, the shape of which can be seen in Fig. 5 and which prevents liquid from being thrown upwards through the chuck 15 and the substrate 16. At about this height there is also a lateral process opening 88, which is usually closed by a cover (not shown) and through which additional devices can be introduced into the process chamber 11. The screen 86 has an interruption in the area of this opening 88, if this opening 88 is provided.

Above the aperture 86 there are also housings or receiving elements 90 for nozzles 94. All housings 90 are arranged at the same height. As Fig. 4 shows, four such housings 90 can be provided, all of which are arranged radially and pointing downwards.

Fig. 10 shows such a housing 90, which is welded into a hole in the wall 91 of the process chamber 11 above the worktop 40, see the weld seams 89. The housing 90, like the wall 91, is made of a suitable plastic, preferably natural polypropylene. It is cylindrical in its basic shape and has a conical inner surface 92 on the side of the process chamber 11, which tapers towards the process chamber 11 and serves as a base for a spherical section

93 of a nozzle 94, which is preferably made of titanium. The nozzle 94 is usually a single-component nozzle and is used, for example, for injecting organic solvents, e.g. alcohols or ketones, but a multi-component nozzle is also possible. Its actual nozzle part is provided with a spray nozzle 95, the wide jet of which can be adjusted within wide limits by rotating the ball 93 in the housing 90, as can be clearly seen from Fig. 10. Other possible positions of the nozzle 94 are indicated in Fig. 10 with dotted lines.

The conical section 92 is adjoined - towards the outside - by a cylindrical section 96, the inner diameter of which corresponds approximately to the diameter of the spherical section 93.

A tubular pressing member 97 is inserted into it, which has conical sections 97' and 97' at both ends.

97 *'. The section 97' rests against the spherical section 93 and serves to lock it by pressing it. The section 97'' enables - as shown - the radial deflection of a cylindrical section

98 of the nozzle 94, to which a connecting line 100 is connected during operation.

The end of the pressing member 97 facing away from the spherical section 93 protrudes from the housing 90 and rests against a pressing ring 102, which can be pressed against the pressing member 97 in the manner shown by means of screws 103, which are screwed into corresponding threads of the housing 90. If the screws 103, of which only one is shown in Fig. 10, are loosened, the nozzle 94 can be freely adjusted and then fixed in the desired spatial angular position by tightening the screws 103. In practice, this has proven to be extremely advantageous. Since the substrate 16 is rotated by the motor 17 during operation, four nozzles, for example, aimed at different points on the substrate 16 are sufficient. If the device 10 is adjusted to a different substrate size, e.g. by switching from substrates of size 5x5 inches to those of size 3x3 inches

W β "■ ■

, the nozzles 94 can be easily adjusted.

Above the housing 90 for the nozzles 94 there is a horizontal slot 106 which, according to Fig. 4, has an angular extension of approximately 120° and which has a narrow section 106' of approximately 75° in length and a wider section ¹⁰⁶ ' of approximately 45° in length, see especially Fig. 9. This slot 106 serves as a process opening for a special feature of the device 10. If this special feature is not required, the slot 106 is also not required and can then be omitted.

i.e. the wall 91 is then continuous. As shown in Fig. 4, the slot 106 extends clockwise to approximately the middle of the process opening 88, or in terms of clock time, and with reference to Fig. 4, from the 10 o'clock position to the 2.30 o'clock position, with the narrower slot 106' extending approximately from the 10 o'clock position to the 1 o'clock position.

A circular process opening 108 is located slightly higher than the slot 106, and, as shown in Fig.

4, in the 3 o'clock position. The process opening 108 serves according to Fig. 11 to introduce a device 110 for dispensing acid, which is shown here as an example of special equipment and is not part of the basic equipment of the device, i.e. which is also omitted in certain applications

The device 110 has a horizontally extending tube 112 which is mounted on a carriage 113 which can be moved linearly on a carriage track 114 by means of a pneumatic cylinder (not shown).

At the left end of the tube 112 - in the process chamber 11 - there is a downwardly projecting acid spray device 115, on which there can be three nozzles, for example, one for HNO ₃ , one for H ₂ O ₂ , and one for H ₂ SO ₄ . These three

These three substances are supplied to nozzles via the pipe 112 and a flexible line 116, depending on the control command, via separate supply lines and via corresponding microfilters, from storage bottles located inside the device 10.

Fig. 11 shows the acid spray device 115 in two different positions, namely once - shown with solid lines - above the substrate 16, and secondly, shown in dashed lines, in its parking position on the inner edge of the process chamber 11, i.e. close to the wall 91. The carriage 113, the line 116, etc. are also shown in these two different positions. These two end positions are monitored by corresponding limit switches 114', 114" (Fig. 17), which are not shown in Fig. 11. A locking mechanism ensures that acid can only be supplied to the acid spray device 115 if it is above the substrate 16 and the corresponding limit switch indicates this. Also, only one of the acids can be selected at a time, and for this acid to be switched on, it is also a prerequisite that the door 35 is closed and that the drain valve 26 (Fig. 13) is connected to the outlet B (for acids). When acid is supplied, the speed of the motor 17 is also automatically limited, e.g. to a maximum of 150 rpm. After the acid supply has ended, water is automatically rinsed via nozzles 124, which are described below, whereby the position of the drain valve 26 cannot be changed. Only then can the door 37 be opened. When the door 35 is opened, all acid is flushed out of the process chamber 11 and the operating personnel cannot therefore be harmed by acid.

As shown in Figures 5, 7 and 8, a screen 120 is welded to the wall 91 above the process opening 108. This screen 120 extends as shown in Figure 8 to the opening 30, i.e. over approximately 270°, since the opening 30 forms an angle beta of approximately 90°. The screen 120 extends from its attachment to the wall 91 diagonally to

inwards and upwards, e.g. as shown at an angle of about 30° to the horizontal. As shown in Figs. 5 and 7, the diaphragm 120 has a gradient with an angle gamma of e.g. 2°, whereby the highest point, which is indicated in Fig. 7 by the dimension d, can be in the 12 o'clock position with reference to Fig. 4, for example, and the lowest points are at the two ends 120' and 120 ¹ ' of the diaphragm 120. (The diaphragm 120 is not shown in Fig. 9.) If liquid drips from above onto the diaphragm 120, it is collected by it and directed to the points 120' and 120'' and flows there vertically downwards along the wall 91 of the process chamber 11 and finally reaches the channel 23 and via the line 25 to the drain valve 26.

Above the aperture 120, the nozzles 124 mentioned above are arranged, which serve to fill the process chamber 11 with deionized water (hereinafter:

Di-water). As shown schematically in Fig. 8, preferably six nozzles 124 are arranged evenly distributed in the area of the upper edge of the process chamber 11. For this purpose, corresponding fastening and connection holes 125 are provided in the wall 91, which lead to an annular channel 126 in a flange 127, which is provided with two connections 128 for supplying Di-water. The flange 127 also extends approximately over 270° to the opening 30, see Fig. .

For the sake of clarity, only one of the nozzles 124 is shown in Fig. 7, which is preferably adjustable and sprays radially inwards and downwards. Its nozzle mouthpiece 124' is - as clearly shown in Fig. 7 - radially further outward than the inner edge 120' of the aperture 120, so that water drops 130 that drip out of the nozzles 124 after they are switched off fall onto the aperture 120 and are diverted by it. This is a very advantageous solution and prevents these drops 130 from falling directly into the process pot 21 and causing damage there.

The process chamber 11 can be provided in the area of its opening 30 with lateral support walls 132, 133, see Fig. 9, which extend from the flange 127 diagonally downwards to the work plate 40. These are only shown in Figs. 1, 2, 4, 9 and 12.

A drainage channel 135 is provided on the worktop 40, which surrounds the process chamber 11 in an approximately C-shape and leads to an opening 136 through which collected liquid can flow into the interior of the closed housing 12. An additional device (optional) can also be attached in the area of the opening 136.

The drain slide 26 according to Figures 13 to 16 is interlocked with the other functions of the device 10 and for this purpose has a microswitch 140 which, by means of a scanning roller 141, scans a cam 142 which is arranged on an actuating shaft 143 of the drain slide 26. (The microswitch 140 is not shown in Figure 13.) The shaft 143 is in turn driven by a gear motor 144 which can preferably only drive this shaft in the direction of rotation 188 (Figure 13). The gear motor 144 is attached to a support plate 145 which is attached to a base plate 148 of the drain slide 26 via stud bolts 146. The shaft 143 passes through a central recess 149 of this base plate 148 and to a rotatable, hollow part 150, to whose radial opening 152 a tube 153 curved by approximately 90° is attached so that its opening points downwards. The hollow part 150 also has an axial opening 154 on its upper side, which widens upwards in the form of a funnel 155, and this axial opening 154 is connected via a bend 156 to the radial opening 152 and then via the tube 153 to its downwardly projecting opening 158. From the axial opening 154 to the opening 158 there is thus an S-shaped, flow-optimized channel in which no contaminants can settle and which can be cleaned extremely easily if necessary.

The upper end of the hollow part 150 is guided in a recess 161 of a cover 160, the shape of which is clearly shown in Fig. 14. A seal 162, e.g. made of silicone rubber, is attached to this cover 160 around the recess 161, and the free end 163 of the drain pipe 25 can be simply and easily releasably inserted into the central opening of this seal, approximately up to the position 163' shown in dashed lines, in which this end 163 is located inside the funnel 155, but at a distance from it in order to enable free rotation of the hollow part 150.

The base plate 148 also has three funnel-shaped recesses 165, 166 and 167, which are evenly distributed in the base plate 148 at intervals of 120°. Fig. 15 shows particularly clearly the shape of the funnel 166* of the recess 166. A line is connected to the bottom of each of the recesses up to 167, namely a line 170 is connected to the bottom of the recess 165 (typically by welding) which leads to connection B (for acids). A line 171 is connected to the recess 166 which leads to connection A (for deionized water). And a line 172 is connected to the recess 167, which is not shown in Fig. 13, which leads to connection C (for organic solvents).

As shown in Fig. 14, in operation the free end 158 of the curved tube 153 is spaced from the respective opening into which it discharges, the funnel, e.g. the funnel 166' in Fig. 15, collecting and receiving the liquid emerging from the opening 158 and directing it to the respective outlet A, B or C.

The recesses 165, 166 and 167 are located at the bottom of a circular recess 175 of the stationary plate 148. This circular recess 175 has a vertical wall 176 on the outside and an inclined wall 177 on the inside, which merges into a flat section 178 in which a seal 179 is arranged in a recess 180.

&phgr; ujt &igr;»

The seal 179 serves to seal against the opposite underside of the hollow part 150, see Fig. 14.

The bottom of the recess 175 is designed according to Fig. 15, i.e. starting from the recess 166, it rises on both sides to a highest point 184 and then falls again, namely from the highest point 185 to the recess 167, from there (clockwise, based on Fig. 16) rising again to the next highest point 186, from there falling again to the recess 165, and from there rising again to the highest point 184. The points 184, 185 and 186 can, for example, be the same height. They each represent a watershed, i.e. point 184 is a watershed between recesses 165 and 166, point 185 is a watershed between recesses 166 and 167, and point 186 is a watershed between recesses 167 and 165. "Watershed" is used generically here, and therefore applies equally to acids or organic solvents, i.e. if the movable tube 15 3 moves in the direction of arrow 188 in Fig. 13, e.g. from recess 165 to recess 166, the liquid emerging from it flows to recess 165 until it reaches the highest point 184, but after exceeding the highest point 184 it flows to recess 166. This prevents Drain valve 26 somewhere liquid accumulates.

The drain valve 26 according to the invention can of course also be designed for a different number of drains, e.g. for only two drains, or for 4 or 5 drains. It can be dismantled and cleaned very easily if the need arises, and saves the previously usual multitude of valves and lines in such devices. It is made entirely of plastic, e.g. from natural polypropylene.

Fig. 17 shows a preferred structure of a microprocessor control for the device 11. This control has a microprocessor 190, to which a read-only memory ROM 192 is assigned, which contains the previously mentioned "hard-wired" ¹¹ program steps, furthermore a RAM 193 for storing the programs and an input device 194, e.g. a keyboard, a floppy disk drive or the like, as well as display devices (not shown) as are usual in such controls.

The microprocessor 190 is connected to the devices to be controlled via an input/output interface 195 and, as far as stored in the ROM 192, causes their automatic locking, speed limitation, setting, etc., as stated above and in the following description of the mode of operation.

Connected, as shown, are the drain valve 26 (in the form of its motor 144) and the microswitch 140 of this valve 26, as well as the motor 17 and its tachogenerator 196, as well as the control 200 for the vacuum in the chuck 15, and the pressure sensor 201 for this vacuum. Also connected is the drive of the pump 204 for the di-water that is fed to the nozzles 124, and the flow monitor 205, which monitors whether water is flowing to the nozzles 124. Also connected are the actuation of the slide 114 for the acid spray device 115 and the two limit switches 114', 114'" of this slide 114.

The drives for the three acid pumps 210, 211 and 212 (for different acids) and their associated flow monitors 213, 214 and 215 are also connected. The pumps 210 to 212 are, as already described, diaphragm pumps.

Also connected, as shown, are the motor 47 of the door drive 45, as well as the two limit switches and 221 of the door 35, which detect whether the door 35 is in its upper or lower end position.

Finally, the valve 223 is also connected, by means of which nitrogen is supplied to the motor 17 (via the line 71 of Fig. 12), and also connected is the pressure switch 224, by means of which the pressure of this nitrogen is monitored.

The three nozzles 94 (and possibly also 84) are each connected via an associated control valve 226, 227 or 228 to three pressurized containers (not shown) with the solvents S1, S2 or S3. The valves 226 to 228 are, as shown, connected to the interface 195 via corresponding control lines.

In the same way, additional devices can be connected if the need arises, and the connections for these can already be provided on the interface 195 to enable future expansions. If an expansion is required, the ROM 192 may have to be replaced with a different version.

How it works

Before starting any work step, a substrate 16 that is to be subjected to some process, e.g. cleaning, must be placed on the chuck 15. The substrate 16 is held there by vacuum (at the openings 54) when a process is running.

When a process starts, the "Vacuum Chuck" output is always set on the microprocessor 190, i.e. the valve 200 is switched on. The vacuum switch 201 is provided to monitor the vacuum. If, for example,

If there is no feedback within 5 seconds that a vacuum is present, the process is aborted and the error is reported. This is an important safety feature

■:■ &rgr; 3 &bgr;

^ a ■*

If a process is interrupted with an emergency stop, the valves are normally de-energized and the motor 17 is switched off. However, since the motor 17 continues to run for some time even in this state due to the mechanical energy stored in it, the vacuum on the chuck 15 must be maintained during this time so that the substrate 16 is not thrown away from the chuck 15. For this reason, if the process is suddenly stopped, the vacuum on the chuck 15 is maintained by appropriate measures that are familiar to those skilled in the art. The vacuum can also be switched on manually. However, it cannot be switched off manually or by program steps during a process as long as the motor 17 is running.

The individual process steps in the processing of a substrate 16 naturally depend on its properties, as already described in detail at the beginning, as well as on the work to be carried out, and finally on the various possible special features of the device 10, so that overall there is a great deal of variability.

Normally, all process steps are controlled by the program stored in memories 192 and 193. And different programs can be stored in memory 193 for this purpose, depending on the individual needs of the user. These programs can be partly programmed, partly entered by so-called teach-in.

However, what all programs have in common is that certain program variants are excluded by internal "hard-wired" program steps (in ROM 192), as already described for some cases. For example, during a process the vacuum on chuck 15 cannot be switched off by a program step, and even after the end of the process only when motor 17 has stopped. These hard-wired

Program steps represent very important, inventive features in this device because they form a protective barrier against improper operation.

The operation of the acid spraying device 115 according to Fig. 11 has already been partially described. It is important that after completion of the acid cleaning by means of the nozzles 124 (Fig. 7), the process chamber 11 is forcibly rinsed from above with deionized water by activating these nozzles 124 for e.g. 15 seconds, whereby, as already explained, the position of the drain valve 26 (acid) cannot be changed.

If the process of acid cleaning a substrate 16 is interrupted for any reason, a rinsing process with deionized water also takes place automatically via the nozzles 124. Only after this rinsing process can the door 35 be opened.

Acid cleaning using the device 115 is used, as already described at the beginning, to clean chrome masks, chrome oxide masks and iron oxide masks. The acid can be heated before spraying, which is very advantageous, because this results in a better cleaning effect. It is pumped using one of the three diaphragm pumps 210, 211 or 212 (Fig. 17). On the inside of the process chamber 11, the pipe 112 is very advantageously surrounded by a bellows (not shown), e.g. one made of PTFE, which then also securely closes the process opening 108 of the process chamber 11 from the inside. It seems important here that the pipe 108 has two functions, namely, holding and moving the nozzle 115 and, secondly, supplying the various acids.

Solvent cleaning

At least one of the nozzles 84 and/or 94 is used for resist coating. When using an organic solvent, the resist-specific solvent, e.g. acetone, is discharged from one of the nozzles 94 and possibly one of the

* A Φ ■

Nozzles 84 continuously spray the substrate 16, which rotates at 300 rpm, for example.

To remove the coating from resists of the types AZ 1350, AZ 1450, S 1400 and PPS, 5 to 7 % NaOH or KOH is sprayed onto the substrate from one of the nozzles 94 (and if necessary one of the nozzles 84).

16, with intervals of 10 seconds spraying - 20 seconds pause, 10 seconds spraying, etc., while rotating the substrate 16 at e.g. 80 rpm. The alkaline solution should be heated to approx. 60° before spraying in order to achieve a better cleaning effect.

The microprocessor control 190, 193 has, as shown in Fig.

17, three outlets for cleaning, one

for organic solvents, one for alkaline solvents, and one for deionized water, which can also be sprayed onto the substrate 16 from one of the nozzles 94 (and possibly also one of the nozzles 84). These outputs are only active when the acid spray device 115 is in its park position and this has been reported by the associated limit switch, as already described.

The outputs of the interface 195 control, as already described, the valves 226, 227 and 228.

If solvent cleaning has been selected, all other processes are blocked and the drain valve 26 is forced into its defined position for solvent drainage. Furthermore, the speed of the motor 17 is limited, for example, to a maximum of 150 rpm. The solvent cleaning then takes place in the manner described above, depending on the solvent used.

After the solvent cleaning is complete, the substrate 16 is rinsed for at least 60 seconds with deionized water from one of the adjustable nozzles 94 (and if necessary one of the nozzles 84). If the deionized water is heated to approx. 70° C, the rinsing time can be shortened by approx. 50%. The nozzle 84 is used for rinsing the back of the substrate

! rf =* tt --j

■;

16 and is a special feature. During this flushing, the position of the drain valve 26 ("solvent") cannot be changed.

If the solvent cleaning is interrupted for any reason, the upper nozzles 124 are first rinsed with deionized water. Only after this rinsing process can the door 35 be opened.

The door 35 is, as already described, provided with the sensor 221 for its closed position (Fig. 2) and the sensor 220 for its open position (Fig. 1), e.g. with suitable limit switches, or with contactless sensors.

If the start of any process is entered, the door automatically moves upwards until the sensor 221 for the closed position is reached. Only then can the actual process begin. At the end of the process, i.e. usually after rinsing with deionized water from the upper nozzles 124, the door 35 is automatically moved downwards by the electronic control.

Switchable drain valve 26

As already described, this has three positions, which are reported via the microswitch 140 (Fig. 14).

In order to achieve exact repeatability of the positioning, the slide 26 can preferably only be rotated in the direction of the arrow 188 (Fig. 13), i.e. only in one direction of rotation. The respective discharge position is automatically locked via the ROM 192 with the activation of a corresponding process in the process chamber 11, as already described in detail, and it is impossible, e.g. by programming, to specify a different discharge position than that required by the respective treatment.

monitoring of flushing

The forced flushing with deionized water via the six upper nozzles 124 is monitored by the flow sensor 205.

- 27 - {„ ·;

. :■. L &idigr; -« » ■·■

This only responds when water actually flows to these nozzles 124. If this flow sensor 205 shows no flow, the forced flush is aborted and an alarm is triggered. The door 35 cannot then be opened.

Protective flooding of the motor 17

As already described, the motor 17 and the process chamber 11 are flooded with nitrogen via the valve 223.

Pressure switch 224 is used for monitoring. If there is no protective flooding, e.g. with nitrogen, no process can be started or it is aborted for safety reasons and an alarm is given.

Drying the substrate 16

For drying after rinsing or cleaning with deionized water, the substrate 16 is accelerated in a ramp-like manner to e.g. 4000 rpm within 20 seconds. The moisture is spun off the substrate 16. The user can follow the drying process - with spot lighting of the substrate 16 - based on the interference phenomena that develop. The substrate is then slowed down in a ramp-like manner for a period of 10 seconds. Only when it is stationary can the door 35 be opened.

The large number of safety features, and in particular the di-water rinsing by means of the upper nozzles 124 provided at the upper edge of the process chamber 11, result in an extraordinary operational safety of the device according to the invention.

Naturally, various deviations and modifications are possible within the scope of the invention.

Claims (65)

Protection claims 1. Device for the treatment of semiconductor substrates, masks for semiconductor production, or the like, hereinafter referred to as substrates (16), characterized in that a process chamber (11) is provided for receiving the substrate (16), that means (84, 94, 115, 124) for supplying at least one treatment liquid to the substrate (16) are provided in the process chamber (11), and that a channel (23) with an outlet (24) is provided for the removal of this treatment liquid after it has acted on the substrate (16) and the mist formed by it, which channel (23) is assigned a deflection element (77) in such a way that the liquid and the mist from the process chamber (11) are diverted through this channel (23) and the liquid is at least partially deposited in the channel (23). 2. Device according to claim 1, characterized in that the channel (23) is designed as an annular channel which is provided with at least one drain (24) in the region of its deepest point. 3. Device according to claim 2, characterized in that the deflection element (76, 77) extends in the manner of a hood or a round roof from the region of the center of the annular channel (23) towards the latter. 4. Device according to claim 3, characterized in that the deflection element (76, 77) has in the region of its outer edge a downwardly projecting projection (77) which projects into the annular groove (23). 5. Device according to one or more of claims 2-4, characterized in that radially inside the IjK * β W « A housing (58, 65, 66) for a motor (17) intended to drive the substrate (16) is provided in the annular channel (23). 6. Device according to claim 5, characterized in that means (70, 71, 72) are provided for flooding the housing (58, 65, 66) with a protective gas, in particular nitrogen. 7. Device according to claim 5 or 6, characterized in that a gap (59) for sucking off the gas-liquid mixture flowing through the annular groove (23) is provided between the housing (58, 65, 66) for the motor (17) and a radially inner wall (62) of the annular groove (23). 8. Device according to claim 7, characterized in that the flow resistance of the gap (59) is different at different locations. 9. Device according to one or more of the preceding claims, characterized in that a clamping device (15) for the substrate (16) is provided in a plane above the channel (23), which clamping device can be driven in rotation to rotate the substrate (16). 10. Device according to one or more of the preceding claims, characterized in that a wall of the channel (23) merges into a wall (21') of the process chamber (21) and extends upwards from the channel (23). 11. Device according to claim 10, characterized in that at least one screen (86) is provided on the wall (21') and above the channel (23), which is designed as protection against splashing up of treatment liquid reflected from the substrate (16). 12. Device according to one or more of the preceding claims, characterized in that in the process chamber (11, 21) at least one nozzle (84, 94, 115, 124) for Introduction of treatment fluid into the'pjrozejßkaHimer "; is intended. 13. Device according to claim 12, characterized in that the at least one nozzle (94, 115, 124) is provided on a wall (91) of the process chamber (11). 14. Device according to claim 12 or 13, characterized in that in the region of the upper edge of the process chamber (11) a plurality of nozzles (124) are provided. 15. Device according to claim 14, characterized in that in the region of the upper edge of the process chamber (11) provided nozzles (124) are associated with a drip guard (120) which catches drops (130) falling from these nozzles (124) after they are switched off. 16. Device according to claim 15, characterized in that the drip protection is designed in the form of a screen (120) which is arranged below the nozzles (124) provided in the region of the upper edge of the process chamber (11) and catches the drops (130) thereof. 17. Device according to claim 16, characterized in that the aperture (120) has a gradient in order to drain liquid (130) dripping onto it. 18. Device according to one or more of the preceding claims, characterized in that a nozzle housing (90) for mounting a nozzle (94) for spraying treatment liquid onto the substrate (16) is provided in the wall (91) of the process chamber (11). 19. Device according to one or more of the preceding claims, characterized in that at least one nozzle (84) is provided on the deflection element (76, 77) or in its vicinity in order to spray the substrate (16) from below. 20. Device according to one or more of the preceding claims, characterized in that above the substrate (16) and in the vicinity of the same in the process chamber (11) at least one nozzle (94) for spraying an organic solvent is provided. 21. Device according to one or more of the preceding claims, characterized in that above the substrate (16) and in the vicinity of the same in the process chamber (11) at least one nozzle (94) for spraying a lye is provided. 22. Device according to one or more of the preceding claims, characterized in that above the substrate (16) and in the vicinity of the same in the process chamber (11) at least one nozzle (94) for spraying di-water onto the substrate (16) is provided. 23. Device for the treatment of semiconductor substrates, masks for semiconductor production, or the like, hereinafter referred to as substrates (16), in particular according to one or more of the preceding claims, characterized in that a process chamber (11) is provided for receiving the substrate (16), which has a wall (21', 91) which has a receptacle (15) for the substrate (16) at least partially surrounds that in this wall at least one receiving member provided with a recess (96) (90) is provided for a nozzle (94), and that in the recess (96) of this receiving member (90) a nozzle (94) is arranged. 24. Device according to claim 23, characterized in that the nozzle (94) has a spherical section (93), and that this spherical section (93) is arranged in the recess (96) between a fixed inner surface (92) of the recess (96) and a detachable pressing member (97). 25. Device according to claim 23 or 24, characterized in that the wall (21', 91) of the process chamber (11) and the receiving member (90) are made of plastic and are connected to one another by plastic welding (89). 26. Device according to claim 24 or 25, characterized in that the pressing member (97) is assigned a pressing ring (192) which is arranged outside the process chamber (11) and is detachably connected to the receiving member (90). 27. Device according to one or more of claims 23 to 26, characterized in that the nozzle (94) is made of titanium. 28. Device according to one or more of claims 23 to 27, characterized in that the nozzle (94) is designed as a single-substance nozzle. 29. Device according to one or more of claims 23 to 28, characterized in that the nozzle (94) has a mouthpiece (95) designed as a wide-jet nozzle. 30. Device for the treatment of semiconductor substrates, masks for semiconductor production, or the like, hereinafter referred to as substrates (16), in particular according to one or more of the preceding claims, characterized in that a process chamber (11) is provided for receiving the substrate (16), which is not closed by a door or the like above the receptacle (15) for the substrate (16). 31. Device according to claim 30, characterized in that the process chamber (11) is provided on its side intended for operation with a door (35) which is displaceable essentially in a vertical direction between a closed position (Fig. 2) and an open position (Fig. 1). 32. Device according to claim 31, characterized in that a work plate (40) is provided around the process chamber (11), which extends to the wall (91) of the process chamber (11), and that a recess (37) for the passage of the door (35) is provided in this work plate (40). 33. Device according to claim 32, characterized in that a housing (12) designed as a collecting container for the liquid mist coming from the process cannon (11) is provided below the worktop (40), and that the door (35) is designed to be retractable into this housing in its open position (Fig. 1). 34. Device according to claims 32 and 33, characterized in that the worktop (40) is welded to the top of the housing (12) designed as a collecting container. 35. Device according to one or more of claims 31 to 34, characterized in that a linear drive (45) is provided for moving the door (35). 36. Device according to claim 35, characterized in that the linear drive (45) is designed to be self-locking, so that in the event of a power failure the door (35) remains in its current position. 37. Device according to claim 35 or 36 and according to claim 33, characterized in that the linear drive (45) is arranged outside the housing (12) designed as a collecting container. 38. Device according to one or more of claims 31 to 37, characterized in that the process cannulas (11) is provided on its side facing the door (35) with at least one essentially vertically extending end edge (31', 32'), and that the door (35) is provided with a section (33, 34) complementary to this end edge (31', 32') which surrounds this end edge in the manner of a labyrinth seal. 39. Device for the treatment of semiconductor substrates, masks for semiconductor production, or the like, hereinafter referred to as substrates, in particular according to one or more of the preceding claims, characterized in that a process chamber is provided for receiving the substrate (16). (11) is provided, and that the process chamber (11) in turn is contained in a container serving as a collecting container for the (11) coming liquid mist formed housing (12) is arranged. 40. Device according to claim 39, characterized in that the process chamber (11) protrudes from the top of this housing (12), for example in the manner of a chimney from a ship. 41. Device according to claim 39 or 40, characterized in that a separating device (23, 76, 77) for separating liquid from the liquid mist coming from the process chamber is provided between the process chamber (11) and the housing (12). 42. Device according to claim 41, characterized in that that the separating device (23, 76, 77) is connected to a drain valve (26) which can be switched to different drains (A, B, C) depending on the liquid separated by the separating device. 43. Device according to claim 42, characterized in that devices (84, 94, 115, 124) are provided in the process chamber for supplying different treatment liquids into the process chamber (11), and that the actuation of these devices is positively locked in each case with an associated position of the drain slide (26). 44. Device according to one or more of the claims 39 to 43, characterized in that the collecting container designed housing (12) is provided with a suction connection (42). 45. Device according to claim 44, characterized in that deflection elements (82) are provided in the suction connection (42) for deflecting the liquid mist flowing through there and for separating liquid from it. 46. Device according to one or more of the claims 41 to 43, characterized in that the separating device has a channel (23) with an outlet (24), which channel (23) is assigned a deflection element (77) in such a way that the liquid and the mist from the process chamber (11) are diverted through this channel (23) and in the process the liquid is at least partially separated in the channel (23). 47. Device according to claim 46, characterized in that the channel (23) is designed as an annular channel which is provided with at least one drain (24) in the region of its deepest point. 48. Device according to claim 47, characterized in that the deflection element (76, 77) extends in the manner of a hood or a round roof from the region of the center of the annular channel (23) towards the latter. 49. Device according to claim 48, characterized in that the deflection element (76, 77) has in the region of its outer edge a downwardly projecting projection (77) which projects into the annular groove (23). 50. Device according to one or more of claims 46 to 49, characterized in that in a plane above the channel (23) a clamping device (15) for the substrate (16) is provided, which can be driven in rotation to rotate the substrate (16). 51. Device according to one or more of claims 39 to 50, characterized in that nozzles (124) for spraying the process chamber (11) with water, in particular deionized water, are provided in the region of the upper edge of the process chamber (11). 52. Device according to claim 51, characterized in that a drip guard (120) is provided below each nozzle (124) to catch those drops (130) which drip out of these nozzles (124) after the spraying has been completed. 53. Device for the treatment of semiconductor substrates, masks for semiconductor production, or the like, hereinafter referred to as substrates, in particular according to one or more of the preceding claims, characterized in that a process chamber is provided for receiving the substrate (16). (11) it is provided that an acid spray device (115) is provided in this process chamber (11), and that this acid spray device (115) has a displacement device (110) which controls the displacement of the acid spray device (115) within the process chamber (11). 54. Device according to claim 53, characterized in that that the displacement device (110) is arranged outside the process chamber (11) and is connected to the acid spray device (115) by a connecting member (112), which connecting member (112) is simultaneously designed to supply at least one acid to the acid spray device (115). 55. Device according to claim 53 or 54, characterized in that the acid spray device (115) is designed for the selective supply of several acids. 56. Device for the treatment of semiconductor substrates, masks for semiconductor production, or the like, hereinafter referred to as substrates (16), in particular according to one or more of the preceding claims, characterized characterized in that a process chamber (11) is provided for receiving the substrate (16), to which a plurality of different treatment liquids, e.g. acids, alkalis, organic solvents or water, can be fed for treating the substrate (16), in particular can be fed at different times, and that these liquids, after their effect on the substrate (16), can each be fed to a drain valve (26) which can be switched to one of several drains (A, B, C) depending on the type of treatment liquid. 57. Device according to claim 56, characterized in that that the drain valve (26) is designed to be electrically switchable (motor 144). 58. Device according to claim 56 or 57, characterized in that the drain valve (26) is provided with a sensor device (140, 141, 142) for detecting its position. 59. Device according to one or more of the claims 56 to 58, characterized in that the drain slide (26) has a base plate (148) which is provided with drain openings (165, 166, 167), each of which leads to an associated drain (B, A or C), and that a rotatable distributor arm (153) is provided for the treatment liquid coming from the process chamber (11), which, depending on its rotational position, feeds this treatment liquid to one of these drain openings (165, 166, 167). 60. Device according to claim 59, characterized in that the distributor arm (153) is arranged above the drain openings (165, 166, 167). 61. Device according to claim 60, characterized in that the opening (158) of the distributor arm (153) facing a drain opening (165, 166, 167) is spaced from this drain opening. 62. Device according to claim 59, 60 or 61, characterized in that the drain openings (165, 166, 167) in the base plate (148) are at least partially funnel-shaped (Fig. 15: 66'). 63. Device according to one or more of claims 59 to 62, characterized in that the base plate (148) on its side facing the distributor arm (153) between the drain openings (165, 166, 167) is provided with sections that rise from a drain opening (e.g. 166) to a "watershed" (e.g. 184 or 185) and fall from there to the next drain opening (e.g. 165 or 167). 64. Device according to one or more of claims 59 to 63, characterized in that the rotatable distributor arm (53) is provided on its inflow side with an upwardly opening, preferably funnel-shaped inflow opening (154, 155), and that the end of the supply line (25, 163) for the treatment liquid in the assembled state is at a distance from this inflow opening (154, 155). 65. Device according to one or more of the preceding claims, characterized in that the process chamber (11) has a substantially circular plan.