Assembly for processing substrates

An assembly for processing substrates, which processing comprises a vacuum deposition process, such as, for instance, sputtering, CVD or PECVD, which vacuum deposition process is carried out in at least one process chamber, the assembly being provided with a conveying device for moving the substrates from a vacuum lock to a process chamber, the conveying device, which extends in a vacuum space, permitting a continuous conveyance of a substrate adjacent the at least one process chamber and permitting an intermittent conveyance adjacent at least the at least one vacuum lock.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to the Netherlands patent application no. 1020633 filed May 21, 2002, the entire contents of which is incorporated by reference in its entirety.

This invention relates to an assembly according to the preamble of claim1.

Such an assembly is known, for instance, from applicant's international patent application WO 02/04697.

The conveying device is there formed by a disk on which a number of substrates can be placed. During the introduction of a substrate into the vacuum chamber or the removal of a substrate from the vacuum chamber via a vacuum lock, the disk must stand still. This has as a consequence that during loading and unloading the substrate situated adjacent the process chamber likewise stands still. In vacuum deposition, however, it is often preferable to advance the substrate during the vacuum deposition process. The advancement of the substrate through the process chamber leads to the application of a layer of better uniformity. The known apparatus is not suited for moving a substrate through or along a process chamber, because the conveying system imposes a standstill of the substrate.

The object of the invention is to improve an assembly of the type described in the preamble, such that the above-outlined problem is thereby solved, and to that end the invention provides an assembly that is characterized by the features of claim1.

Such an assembly has the advantage that the substrates can be moved along the process chamber in which the vacuum deposition takes place, while elsewhere in the assembly a substrate can be introduced into the vacuum space or can be removed therefrom. This yields a better uniformity of the layer thickness formed in the vacuum deposition process.

It will be clear that the term vacuum should not be construed as absolute vacuum. Indeed, the vacuum deposition does not take in absolute vacuum as well. In a PECVD or CVD-process a fluid such as a gas is introduced in the process chamber. The skilled person knows what is meant by vacuum, namely, conditioned circumstances, i.e. circumstances which are desired during the processing and/or transport of the substrates and which can be created by virtue of the fact that the space in which the conveying device extends is closed off from the environment. These conditioned circumstances also include a vacuum space filled with inert gas.

According to a further elaboration of the invention, the assembly is characterized by the features of claim2.

Due to the carriers being drivable independently of each other, some carriers in the assembly can be advanced continuously while other carriers in the assembly are advanced intermittently. In the path in which the carriers are advanced continuously, they can be coupled to each other, so that a closed series of carriers can be advanced under one or a number of process chambers arranged behind each other. This prevents the rails disposed under the process chambers from being contaminated by the vacuum deposition process. Moreover, this leads to a better efficiency of the vacuum deposition, since virtually all particles released during the deposition end up on substrate surface and hence contribute to the formation of a desired layer on the substrate surface.

According to an alternative further elaboration of the invention, the assembly is characterized by the features of claim18.

Such an embodiment is relatively simple and hence economically advantageous. Specifically for mass production, this variant offers advantages, since the conveying speed of the main conveyor can be accurately tuned to the vacuum deposition process and the supply and discharge conveyors can be accurately adjusted accordingly, yielding a highest possible production. The flexibility of such an assembly, however, is considerably less than that of the embodiment with the carriers that are drivable independently of each other.

The advantage of the embodiment with the independently drivable carriers is that the carriers can be individually pre-heated to a temperature desired for the respective substrate. Varying the pre-heating per substrate is therefore one of the possibilities. Moreover, the manner in which the substrate is cooled off can be varied individually in the carrier embodiment.

This is because the traveling speed of the carriers, and hence the time during which a respective carrier remains in a heating path and a cooling path, can be varied. Moreover, the layer or layers to be applied during the vacuum deposition processes can be varied in thickness by varying the traveling speed of a respective carrier in that path.

The exemplary embodiment of the assembly represented inFIG. 1is provided with a vacuum space1in which extends a conveying device2. The conveying system2, which is shown in more detail inFIG. 2, comprises a first path3in which the carriers4advance intermittently. The conveying system2is further provided with a second path5, in which the carriers4advance continuously. A discharge end3.1of the first path3is connected via a third path6with a supply end5.1of the second path5. A discharge end5.2of the second path5is connected via a fourth path7with a supply end3.2of the first path3. In the second, third and fourth paths5,6, and7, respectively, the carriers4advance continuously. In the first path3the carriers4advance intermittently. In the first path3and the second path5extend rails8and9, respectively. The carriers4, as is clearly represented inFIG. 8, are provided with a bearing10,11through which the carrier4is mobile over the rails8,9.

As is clearly shown inFIG. 8, the carrier4is provided with a base part12which is connected via a plane-parallel spring13with an intermediate part14. Normally, the intermediate part14rests on supports15which are connected with the base part12. The plane-parallel spring13, however, allows a vertical displacement of the intermediate part14relative to the base part12. Arranged on the intermediate part14, via a thermally insulating connection16, is a substrate carrier part17in which a heating element is included. The heating element can heat a substrate disposed on the substrate carrier part17to a temperature of about 450° C. Owing to the thermally insulating connection16, which may be formed, for instance, by a three point support having a very small contact surface, the intermediate part14will acquire a temperature of about 120° C. at most. Since the connection between the intermediate part14and the base part12has been effected via the plane-parallel spring13, a substantial thermal insulation can be effected there too, so that the base part will reach a temperature of at most about 60° C. Adjacent the vacuum locks18,19—and, for that matter, also adjacent a station20in which residual material can be sucked up from the substrate carrier part17, and stations21,22in which the substrate carrier part17in the vacuum space can optionally undergo a cleansing etching operation—press-up elements23are present, by means of which the intermediate part14of the carrier part4can be pressed up. Thus, the intermediate part14can be pressed against a lower edge of a limitation24of a vacuum lock opening, so that the substrate carrier part17is situated in the opening of the vacuum lock18,19and is insulated from the vacuum space1. Thereafter the cover46,47(seeFIG. 4) can be taken from the limitation24of the vacuum lock18,19, so that the substrates can be removed from the substrate carrier part17. It will be clear that a considerable force is required to keep the intermediate part14pressed against the lower edge of the limitation24when the cover46,47has been removed from the limitation24of the vacuum lock18,19, since under those circumstances the atmospheric pressure will tend to push the intermediate part14down forcefully. To resist this force, in the present exemplary embodiment, the press-up elements23are moved up and down by means of a toggle joint lever system26. The toggle joint lever system26is clearly visualized inFIG. 9and is energized by a piston/cylinder assembly27.

FIG. 8further shows a bottom wall28and a top wall29which bound the vacuum space1. In the base part12of the carrier4a series of magnets30are included. This series of magnets30is also clearly visible inFIG. 10. The magnets30are part of the drive of the carrier4. Outside the vacuum space1, under the bottom wall28, a series of coils31are arranged. The coils31can be excited such that the carriers4can be advanced over the rails8,9, respectively, with any desired speed. To enable the conveyance of the carriers4in the third and fourth paths6,7, respectively, these paths are provided with cross rails33,34, respectively. Over these cross rails33,34, a cross conveyance carrier35,36, respectively, is mobile.

The cross conveyance carrier36of the fourth path7is represented in more detail inFIG. 11. It is clearly visible that the cross conveyance carrier36is provided with rail parts37extending perpendicularly to the cross rails34and which can be aligned with the rails8,9, respectively, of the first and second paths3,5, respectively. The cross conveyance carrier36is also provided with magnets38cooperating with coils39. The coils39are arranged outside the housing of the vacuum space1.

Referring toFIG. 1, it is further observed that after the vacuum lock19for introducing a substrate into the vacuum space a carrier4is moved to the third path6. In the third path, carrier4is moved with the aid of the cross conveyance carrier35in the direction of the second path5. In the third path6pre-heating lamps are arranged, by means of which the substrate can be pre-heated to a temperature of about 300° C. Next, the carrier4moves into the second path5and there a further heating of the substrate to about 400° C. takes place. This further heating takes place with the aid of the heating element contained in the substrate carrier part17. The substrate proceeds to pass a number of process chambers40,41,42in which a number of vacuum deposition processes take place. One can here think of, for instance, sputtering or a PECVD process. As is clearly visible inFIG. 2andFIG. 7, the carriers link up with each other, so that the substrate carrier parts17of the successive carriers4form a continuous surface. This prevents the vacuum deposition from contaminating the conveying device, such as, for instance, the rails9. To reduce such contamination still further, each intermediate part14is provided at an upstream end with a nose43and at a downstream end with a recess44in which the nose43is receivable. Thus a kind of labyrinth is formed which prevents particles that come from the vacuum deposition process from contaminating the transport rails8,9or the base parts12with the bearing10,11contained therein. Downstream of the process chambers40,41,42, in the second and fourth paths5and7, respectively, a cooling of the substrate to about 150° C. takes place. Adjacent a supply end of the first path3, further cooling means are provided, for cooling the substrates further to 60° C. The further cooling means can comprise rinsing means44for causing the substrate to be circumfused by a gas, such as, for instance, nitrogen. Downstream of these further cooling means44, a vacuum lock18is disposed for taking the substrate out of the assembly. Downstream of the vacuum lock18for taking out the substrates, a cleaning station20is arranged. Such a cleaning station can comprise, for instance, a vacuum cleaner to clean the substrate carrier part17by suction.

Further, in the present exemplary embodiment, downstream of the cleaning station20, two etching stations20,21are provided for cleaning the carrier4, at least the substrate carrier part17thereof, by etching.

FIG. 1additionally shows a carrier supply and/or discharge station45for respectively supplying and discharging carriers4into and out of the vacuum space1of the assembly. Such a carrier supply and/or discharge station45is naturally also provided with an air lock to prevent the vacuum in the vacuum space1from being disturbed during the introduction of a carrier4into the vacuum space1.

FIG. 12shows, in cross section a second exemplary embodiment of an assembly according to the invention. This assembly is likewise provided with a vacuum space101in which a conveying device for conveying substrates is disposed. The conveying device comprises an endless main conveyor102which has a continuous conveying speed. Upstream of the main conveyor102, a supply conveyor103is arranged which has a downstream end linking up with an upstream end of the main conveyor102. Arranged downstream of the main conveyor102is a discharge conveyor104which has an upstream end linking up with a downstream end of the main conveyor102. The supply conveyor103and the discharge conveyor104are also arranged in a vacuum space101. In the present exemplary embodiment, the supply conveyor103and the discharge conveyor104are endless conveyors which are intermittently drivable. Above the main conveyor102a vacuum deposition chamber105is arranged. Arranged above the supply conveyor103is a vacuum lock106for introducing a substrate, and arranged above the discharge conveyor104is a vacuum lock107for taking out a substrate. The advantage of the endless supply and discharge conveyors is that the conveyor belt thereof can be simply pushed up slightly, with the aid of a movable plate, against the loading opening edge of the vacuum lock106,107. In that condition, the vacuum space is closed off from the opening of the respective vacuum lock106,107and the cover can be removed from this opening for placing or removing the substrate. In the present exemplary embodiment, the vacuum deposition takes place with the aid of PECVD sources108. Naturally, in this exemplary embodiment too, there may be provided means for pre-heating the substrates and means for cooling the substrates. The pre-heating means may, for instance, be integrated into the endless main conveyor102.

It will be clear that the invention is not limited to the exemplary embodiments described, but that various modifications are possible within the scope of the invention as defined by the claims. Although the carriers in the exemplary embodiment are shown to have a substantially horizontal support surface, it will be clear that embodiments in which the substrates are carried by the carriers in a non-horizontal position, e.g. a vertical or angled position, or are suspended under a carrier also fall within the scope of the invention as defined by the claims. Such alternative positions of the substrates can help to prevent or diminish pollution of the substrates.

It is noted that continuous conveyance should be understood to mean not exclusively conveyance at a constant speed but uninterrupted conveyance. Continuous conveyance may very well involve the speed of the carrier being varied. Naturally, it is also possible that continuous conveyance does proceed at a constant speed.