Snubber for pneumatically isolated platforms

1. Field of the Invention

The subject matter disclosed generally relates to the field of vibration isolated tables.

2. Background Information

Semiconductor devices are fabricated using extremely precise process equipment. The process equipment is located within a clean room facility. Clean room facilities typically have a certain amount of vibration that must be isolated to preserve the accuracy of the process equipment. The process equipment may include vibration isolators that isolate a platform or table of the equipment from the vibrating floor of the facility.

The process equipment may include robotic arms and other automated components that move the wafers to and from processing stations. Movement of the wafers can create shock and vibration in the equipment. The shock and vibration can create movement in the equipment which decreases the accuracy of the process. The process typically includes a settling time to compensate for vibration in the system. The settling time increases the overall time required to fabricate the semiconductor device. The increase in process time decreases the manufacturing throughput of the products.

A table assembly that includes a vibration isolator coupled to a table. A snubber is coupled to both the vibration isolator and the table.

FIG. 1 is a side view of a table assembly;

FIG. 2 is a top sectional view of a snubber; and,

FIG. 3 is a perspective view showing an assembled snubber;

FIG. 4 is an exploded view of the snubber.

Disclosed is a table assembly that includes a snubber coupled to both a table and a vibration isolator. The snubber limits relative movement between the table and vibration isolator so that the isolator can more quickly damp movement by the table. The snubber reduces the settling time of the table when subjected to shock and/or vibration loads.

Referring to the drawings more particularly by reference numbers, FIGS. 1 and 2 show a table assembly 10 . The assembly 10 includes a vibration isolator 12 coupled to a table 14 . By the way of example, the table 14 may function as a platform for semiconductor process equipment. The vibration isolator 12 is typically coupled to the floor (not shown) of a building structure.

The assembly 10 further includes a snubber 16 that limits relative movement between the table 14 and the isolator 12 . Limiting movement of the table 14 allows the isolator 12 to more quickly damp the shock and vibration loads applied to the assembly 10 .

The snubber 16 may include an elastomer 18 mounted to the table 14 and a plurality of rollers 20 attached to the vibration isolator 12 . The rollers 20 are coupled to the elastomer 18 to limit relative movement between the table 14 and isolator 12 in both vertical and horizontal directions. By way of example, the elastomer 18 may have a conical shape that allows the rollers 20 to be located within a v-shape groove 22 . The groove 22 limits the movement of the rollers 20 and vibration isolator 12 relative to the elastomer 18 and table 12 . Although a conical shape is shown and described, it is to be understood that the elastomer 18 may have other configurations. For example, the elastomer 18 may have a rectangular slot, or be shaped as a hyperbola.

The elastomer 18 is preferably constructed from an elastomeric material such as rubber, although it is to be understood that element 18 may be constructed from a non-elastomeric material.

The snubber 16 may include three rollers 20 . There are preferably three rollers 20 separated by 120 degrees. Such an arrangement ensures that the rollers 20 limit relative movement between the table 14 and isolator 12 in any direction within a horizontal plane.

Each roller 20 may be pivotally connected to a bracket 26 . The brackets 26 may be connected to a lower plate 28 . The lower plate 28 may have slotted holes 30 that allow the horizontal position of the rollers 20 to be adjusted relative to the elastomer 18 .

The elastomer 18 may be mounted to an upper plate 32 that is attached to the table 14 . The elastomer 18 may be mounted to the upper plate 32 by a bolt 34 attached to a threaded bracket 36 . The vertical position of the elastomer 18 relative to the rollers 20 can be adjusted by turning the threaded bracket 36 . Fine adjustment of the vertical position and stiffness of the elastomer can be made by turning the bolt 34 .

As shown in FIGS. 3 and 4 , the upper plate 32 may include an alignment pin 38 that can be inserted into an alignment hole 40 of the lower plate 28 . The alignment pin 38 and hole 40 allow gross alignment of the elastomer 18 and rollers 20 during the assembly of the snubber 16 to the table 14 and the isolator 12 . The upper plate 32 may also have clips 42 that couple directly to the support plate 45 of the vibration isolator 12 to ensure safe connection of the isolator 12 to the table 14 through the upper plate 32 . A shipping plate 44 may be attached to the upper 32 and lower 28 plates to allow the snubber 16 to be shipped in a relatively aligned position. The shipping plate 44 improves the ease of assembly. The plate 44 is removed after the snubber 16 is attached to the table 14 and isolator 12 .

In operation, a vertical movement of the table 14 will cause the elastomer 18 to engage the rollers 20 and limit such movement. Likewise, a horizontal movement of the table 14 will cause the elastomer 18 to engage one or more rollers 20 to limit such movement.

While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention not be limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those ordinarily skilled in the art.