Material or article handling – Horizontally swinging load support – Swinging about pivot
Reexamination Certificate
1998-06-02
2001-07-31
Bartuska, F. J. (Department: 2167)
Material or article handling
Horizontally swinging load support
Swinging about pivot
C901S015000
Reexamination Certificate
active
06267549
ABSTRACT:
BACKGROUND OF THE INVENTION
In semiconductor manufacturing, robots are commonly used to move wafers from one location to another. The use of efficient robots is particularly important for manufacturing processes in which the wafers are subjected to many chemical processes. Because the different processes are carried out in separate reaction chambers, the wafers have to be transported from one reaction chamber to another in a multiple chamber system. U.S. Pat. No. 5,292,393 to Maydan et al. discloses an example of an integrated modular multiple chamber vacuum processing system. A robot employs a dual four-bar link mechanism for imparting selected R-theta movement to the blade to load and unload wafers in the system of Maydan et al. Other robots of a four-bar link configuration are found in U.S. Pat. No. 5,280,983 to Maydan et al. and U.S. Pat. No. 5,452,521 to Niewmierzycki.
Another type of robot arm mechanism is known as the frog-leg type mechanism. U.S. Pat. No. 5,655,060 to Lucas discloses a cluster tool robot that employs a frog-leg type dual arm mechanism driven by a drive system to rotate and to stretch or translate in and out of process modules. U.S. Pat. Nos. 5,435,682 and 5,020,475 to Crabb et al., disclose substrate handling subsystems employing frog-leg mechanisms for moving wafers or substrates to and from processing subsystems. A frog-leg robot having walking-beams is disclosed in U.S. Pat. No. 5,569,014 to Hofmeister.
The robot speed is one key factor that limits the production capability or throughput of the equipment, especially in processes that require quick and frequent transport between chambers. To achieve higher throughput, a pair of four-bar link arms have been used to operate a pair of robot blades that are stacked together and spaced from one another. The two robot arms rotate together, but may move in and out independently. After the robot rotates the arms to a chamber and aligns the upper arm with the chamber inlet, the upper arm moves into the chamber to load or unload a wafer. The upper arm is then withdrawn from the chamber, and the robot moves the arms vertically upwardly to align the lower arm with the chamber inlet. The lower robot arm then moves in and out of the chamber to load or unload a wafer. The use of the dual robot arm mechanism essentially increases the overall speed of the robot. While the use of the dual arms increases throughput, the requirement for vertical movement of the robot arms decreases the overall speed and may be undesirable in certain systems.
SUMMARY OF THE INVENTION
The present invention provides a simple and effective wafer handling robot mechanism that operates in a wafer chamber and comprises two independent robot blades for handling wafers, an upper blade surmounting a lower blade, at virtually the same level. Because the two blades are at virtually the same level, they can independently access different wafer chambers or simultaneously access the same chamber without requiring any vertical indexing. As a result, the same wafer lift mechanism can be used in the wafer chamber to lift and remove or replace the wafers on the two blades. Because no vertical indexing is required for the two blades, the present robot system is more efficient and versatile, and can improve throughput by up to about 100% over existing single blade systems.
In accordance with an aspect of the present invention, a robot blade system for moving substrates into and out of a chamber through an opening comprises a first robot blade for supporting a first substrate. A second robot blade is disposed generally above and spaced from the first robot blade by a small distance for supporting a second substrate. A first robot arm is coupled to the first robot blade for moving the first substrate and at least a portion of the first robot blade through the opening into the chamber and moving the first substrate and the first robot blade out of the chamber. A second robot arm is coupled to the second robot blade for moving the second substrate and at least a portion of the second robot blade through the opening into the chamber and moving the second substrate and the second robot blade out of the chamber. The second robot arm is independently movable from the first robot arm. This structure allows the first and second robot arms to move independently the first and second substrates, respectively, on the first and second robot blades into and out of the chamber. Because the second robot blade is spaced from the first robot blade by a small distance, the two robot blades are at virtually the same level and can access the same chamber without requiring any vertical indexing.
In addition, the robot blades can be tapered and include hollow portions to reduce the weight of the blades, thereby minimizing deflection and vibration of the blades, especially if they are long. The blades are advantageously made of a material having a strength-to-weight ratio that provides a bending deflection of the blades of under about 0.5 mm. In one example, the robot blades are up to about 300 mm in length and comprise sapphire.
Another aspect of the invention is a system for moving substrates into a housing through an opening which defines a plane spaced between an upper boundary and a lower boundary, where the plane is spaced from the lower boundary by a lower gap and spaced from the upper boundary by an upper gap. The system comprises a lower blade for supporting a lower substrate and an upper blade closely spaced from the lower blade for supporting an upper substrate. The system comprises first member, coupled to the lower blade, for moving the lower substrate through the lower gap into and out of the housing. The system further comprises second member, coupled to the upper blade and independent from the first member, for moving the upper substrate through the upper gap into and out of the housing. Because of the positions and spacings of the upper and lower blades, they can move simultaneously or separately into and out of the opening smoothly without interference.
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patent: 5280983 (1994-01-01), Maydan et al.
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patent: 5452521 (1995-09-01), Niewmierzycki
patent: 5569014 (1996-10-01), Hofmeister
patent: 5636963 (1997-06-01), Haraguchi et al.
patent: 5655060 (1997-08-01), Lucas
patent: 5702228 (1997-12-01), Tamai et al.
patent: 6099238 (2000-08-01), Tsubota
patent: 4-87785 (1992-03-01), None
Brown William
Welch Michael
Applied Materials Inc.
Bartuska F. J.
Townsend & Townsend and Crew
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