Cleaning and liquid contact with solids – Apparatus – Having self cleaning means
Reexamination Certificate
1999-04-09
2001-09-25
Coe, Philip R. (Department: 1746)
Cleaning and liquid contact with solids
Apparatus
Having self cleaning means
C134S095100
Reexamination Certificate
active
06293291
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a method for the treatment of objects, preferably wafers, in an apparatus for the treatment of objects, having at least two process chambers for receiving and treating the objects and a handling apparatus for loading and unloading the process chambers. Furthermore, the invention relates to a corresponding apparatus.
Such a method is used in the course of wafer coating, for example. The customary procedure in this case is that after the program start of the treatment method, firstly all of the process chambers are charged with the wafers to be processed by the handling apparatus. The treatment of the wafers then begins simultaneously in all of the process chambers. This has the disadvantage, however, that, in particular, time is lost and throughput losses arise because the capacity of the handling apparatus is limited. This results from the fact that when a plurality of process chambers are activated simultaneously, too many movements have to be executed by the handling apparatus per time period. Furthermore, during cleaning processes that are necessary within the process chambers and have to be carried out at regular intervals, idle times arise in the method, since the cleaning processes are carried out simultaneously in all of the process chambers. The handling apparatus is not used during the cleaning processes.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method and an apparatus for the treatment of objects, preferably wafers, that overcomes the above-mentioned disadvantages of the prior art devices of this general type.
With the foregoing and other objects in view there is provided, in accordance with the invention, an improved method for treating objects including wafers, the improvement which includes: initially loading a first batch of the objects to be treated into a first process chamber of a plurality of process chambers at a start of a cleaning program with a handling apparatus for loading and unloading the plurality of process chambers; starting a treatment process of the first batch of the objects to be treated; loading temporally staggered a second batch of the objects to be treated into a second process chamber with the handling apparatus; and starting the treatment process of the second batch of the objects to be treated.
In particular, the intention is to provide a method and an apparatus in which the throughput of objects to be treated in the process chambers is increased, and in which, in particular, overlapping of the necessary cleaning processes in the process chambers is prevented or minimized.
In accordance with a first aspect, the invention is achieved by a method described in the introduction which is characterized by the following steps: a) at the program start, loading of the objects into the first process chamber and the beginning of the treatment of the objects are effected; b) subsequently, the loading of the objects into the second process chamber and the beginning of the treatment of the objects are effected in a temporally offset manner by interposing a defined waiting time before the second process chamber is loaded.
In the first instance, the method according to the invention achieves an increase in the throughput of objects to be treated and hence in the productivity of the method and the capital efficiency. In particular, it is advantageous that the implementation of the method requires no structural changes at all to the apparatus for the treatment of the objects. Therefore, the method can be realized particularly cost-effectively and rapidly.
The temporally staggered initial loading of the objects into the individual process chambers provides a possible way of avoiding the disadvantages described above. By way of example, the temporally staggered initial loading and the consequentially temporally staggered beginning of the processing of the objects lead, in particular with continuous processing through the process chambers, to a throughput increase of up to 30% and thus to a considerable increase in efficiency. The reason for this results from the fact that the method according to the invention prevents idling during the necessary cleaning processes. The cleaning processes have to be carried out in each case after the process chambers have been running for a particular duration. The temporally staggered initial loading of the objects into the process chambers now results in that the cleaning processes are also carried out in a temporally staggered manner, with the result that the previously customary overlapping of the cleaning processes in the individual process chambers is obviated or minimized.
The result is a balanced method with a continuous and optimized throughput of objects.
Preferred objects that can be treated by the method according to the invention are wafers, which are coated, by way of example, in the individual process chambers. However, the invention is not restricted to the treatment of wafers, but rather can also be used for the treatment of other objects.
According to the invention, the method may furthermore be characterized by the following steps: c) unloading of the objects from the first process chamber after the end of treatment and renewed loading of objects to be treated into the first process chamber; and d) unloading of the objects from the second process chamber after the end of treatment and renewed loading of objects to be treated into the second process chamber.
In a further refinement, a third process chamber may be provided, in which case the initial loading of the objects into the third process chamber and hence the beginning of the treatment are effected in a temporally staggered manner with respect to the initial loading of the objects into the first and second process chambers. The use of three process chambers enables the throughput of the method to be further improved. Last but not least, the use of three process chambers makes it possible to save entire apparatuses for the treatment of objects. This is advantageous particularly when the apparatuses, for instance in the case of wafer treatment, are located in clean rooms, which usually have only a limited amount of available space. At this point, attention is drawn to the fact that the invention is not, of course, restricted to the use of a specific number of process chambers, so it is conceivable and possible for there also to be more than three process chambers for the implementation of the method.
The individual process chambers are preferably subjected to a cleaning process at intervals, the cleaning process in the individual process chambers being effected in a temporally staggered manner to the same extent as the initial loading and the beginning of the treatment of the objects in the respective process chambers.
In a further refinement, the temporally staggered initial loading and the beginning of the treatment of the objects in the process chambers may be effected temporally cyclically. As a result, the method can be controlled deliberately and in a particularly simple and temporally exact manner, which further improves the achievable throughput.
According to the invention, the temporally staggered initial loading and the beginning of the treatment of the objects in the process chambers may be effected at time intervals of 45 minutes or 90 minutes. These specified times are two advantageous exemplary time values. In principle, the invention is not restricted to specific time values. Rather, the requisite time values emerge from the respective treatment method and the resultant requirements. Typical values in the case of wafer treatment are in the time range of 5 minutes to 120 minutes, but may also go beyond this range.
According to the invention, the program start can be effected at the beginning of the treatment method after a first startup or after an operationally dictated stoppage of the apparatus for the treatment of the objects.
In one refinement, the temporally staggered beginning of the treatment of the objects
Gajewski Volker
Sperlich Hans-Peter
Coe Philip R.
Greenberg Laurence A.
Lerner Herbert L.
Siemens Aktiengesellschaft
Stemer Werner H.
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