Measuring and testing – Testing of apparatus
Reexamination Certificate
2002-03-04
2004-06-08
Williams, Hezron (Department: 2856)
Measuring and testing
Testing of apparatus
C414S222130, C414S935000, C438S014000
Reexamination Certificate
active
06745637
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention refers to a metrology device couplable to a load port of a semiconductor product handling and/or processing tool which tool encloses a mini-environmental atmosphere and has a load port table for supporting devices to be coupled to the load port. The metrology device contains a housing preserving an inner atmosphere, a coupling region for connecting an inner atmosphere to a mini-environmental atmosphere, and a measuring device for measuring a property of a semiconductor product.
In the manufacture of semiconductor products, several process steps are performed by process tools which are, for instance, combined to cluster tools including one wafer handling tool. Within the cluster tools the semiconductor products are handled and processed within a mini-environment that is a clean room atmosphere of higher purity than the clean room atmosphere accommodating operating personnel and the cluster tools. Due to the complexity of modern semiconductor product processing often requires several hundred processing steps, intermediate control of processing results and physical, chemical, or other properties of the semiconductor products is necessary. Often the necessity of controlling such a property arises during semiconductor product processing. In any case, measurements have to be performed during or interrupting, respectively, a rather complex process routine.
With a view to the costs of running processing tools, it would be desirable to minimize the interruption time caused by the measurements. However, due to the mini-environmental clean room requirements, the semiconductor products must not contact the outer atmosphere surrounding the processing tools.
In order to preserve the mini-environmental atmosphere, wafers are intermediately stored in so-called front-opening unified pods (FOUPs) docked at a load port. The load port is a device for loading or unloading FOUPs. Usually, load ports are allocated at front-end process modules for wafer handling and loading and unloading process tools.
The FOUP containing a semiconductor product also preserves the mini-environmental atmosphere around it and hence allows for an air-tight transport of the semiconductor product within the outer clean room atmosphere of minor purity. The semiconductor product in the FOUP is transported to a second load port connected to a measuring tool, unloaded, subjected to the measurement, reloaded and transported to the load port connected to the cluster tool in order to continue the semiconductor processing.
Due to this proceeding, semiconductor products to be measured have to be transported twice. In order to save time and efforts for transport, it would be possible to permanently combine the measurement device with the cluster tool. In this case, FOUP transport would not be required. However, this is not realized up to now because of several reasons.
First, measurement devices are supplied by various engineering companies. Each measurement device of any one of the companies would require high efforts for integration into and interaction with highly automated cluster tools. It is not profitable to spend time and costs for extending the cluster each time when any measurement device of one of the various suppliers is integrated.
Second, such integration efforts would arise already in advance before testing the compatibility of a measurement device and a cluster tool. As the compatibility has to be proven before selecting a measurement device of a particular supplier, the integration costs would add up to the costs of the devices chosen or, with respect to those devices not bought from the other suppliers, would be spent to no purpose.
Finally, present FOUPs and load ports are standardized and therefore offer simple connection to stand-alone measuring devices.
For these reasons, wafers to be subjected to a measurement are transported to and from the load port connected to such measurement device.
A FOUP ordinarily employed for exclusively transporting wafers may contain a sensor for measuring a property of a wafer allocated in the FOUP. As the housing of the FOUP preserves the mini-environment and the FOUP is easily coupled by its coupling region to the cluster tool, the measurement can be performed directly at the load port; the need of transport no longer arises.
The load ports themselves, however, must maintain mini-environmental atmospheric conditions when a FOUP is docked thereto. In no case can any leakage between the FOUP and the load port be tolerated. Therefore, a special seal is located between the load port and the FOUP and surrounds a passage for transferring a wafer between the load port and the FOUP.
Effective passage seals as well as wafer handling require exact positioning of the FOUP relative to the load port. To this end, a load port contains a table with three pins supporting the FOUP when it is docked to the seal of the load port. Exact positioning of the FOUP is provided by the suppliers of the load port only to a certain maximum weight of the FOUP. In 300 mm production, the maximum weight amounts to about 12 kg and approximately corresponds to the weight of a FOUP loaded with the maximum number of wafers allowed.
When a metrology device is integrated in a FOUP, the maximum weight must not be exceeded because otherwise exact positioning could not be granted so that a leakage of the seal might occur. As a consequence, only lightweight metrology devices as sensors requiring little hardware and software equipment can be integrated into a FOUP.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a self-supporting adaptable metrology device which overcomes the above-mentioned disadvantages of the prior art devices of this general type, which, regardless of its dimensions or weight, can rapidly be coupled to a semiconductor product handling and/or processing tool with very little effort and which grants for comparable leakage prevention during coupling and decoupling as the lightweight FOUP does. It is a further object of the invention to provide a metrology device which is adaptable to a semiconductor product handling and/or processing tool via a load port having a load port table and thus being constructed for the coupling of wafer containers (which at the most might contain small and light weight measuring tools) exclusively.
With the foregoing and other objects in view there is provided, in accordance with the invention, a metrology device couplable to a load port of a semiconductor product tool enclosing a mini-environmental atmosphere and having a load port table for supporting devices to be coupled to the load port. The metrology device contains a housing preserving an inner atmosphere, a coupling region for connecting the inner atmosphere to the mini-environmental atmosphere and extends from the housing, a measuring device for measuring a property of a semiconductor product, a transport device, and a support supported by and movable over ground by the transport device. The support supports the housing and the measuring device. The support is dimensioned such that the metrology device is self-supporting in a position appropriate for coupling the coupling region to the load port, the metrology device is thereby couplable to the load port without being supported by the load port table.
According to the invention, the object is achieved by a metrology device of the kind now described which is constructed containing a support which is movable on the ground by the transport device and which support is dimensioned such that the metrology device is self-supporting in a position appropriate for coupling the coupling region to the load port. The metrology device thereby being couplable to the load port without being supported by the load port table.
The general idea underlying the invention is, proceeding from the above-mentioned load port FOUP support, to position the metrology device independently and separately from any maximum weight depending support members of the cluster tool. Whereas according to prior
Gerhard Detlef
Lechner Johannes
Marx Eckhard
Tegeder Volker
Fayyaz Nashmiya
Infineon Technologies SC300 GmbH & Co. KG
Mayback Gregory L.
Williams Hezron
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