Air-bearing chuck

Abstract

An air-bearing chuck includes a nozzle portion and a gas channel portion. The nozzle portion is provided with a plurality of support force nozzles for generating an air cushion on a top surface of the nozzle portion. The gas channel portion includes a first gas channel configured to transmit a first gas to the plurality of support force nozzles to provide support force. Embodiments of the present application can implement that the first gas channel transmits the first gas to the plurality of support force nozzles to provide support force, and an air cushion is generated on the top surface of the nozzle portion by regulating gas flow of the first gas in the first gas channel, thereby keeping a supported object supported by the air cushion stably floating up on one side, away from the top surface of the nozzle portion, of the air cushion.

What is claimed is: 
     
         1 . An air-bearing chuck, comprising:
 a nozzle portion, provided with a plurality of support force nozzles for generating an air cushion on a top surface of the nozzle portion; and   a gas channel portion, comprising a first gas channel configured to transmit a first gas to the plurality of support force nozzles to provide support force.   
     
     
         2 . The air-bearing chuck according to  claim 1 , wherein the nozzle portion further comprises a plurality of openings, and the plurality of openings are arranged alternately with the plurality of support force nozzles. 
     
     
         3 . The air-bearing chuck according to  claim 2 , wherein the plurality of support force nozzles and the plurality of openings are arranged in an axisymmetric pattern on the top surface of the nozzle portion. 
     
     
         4 . The air-bearing chuck according to  claim 2 , wherein the plurality of support force nozzles and the plurality of openings are arranged in a plurality of concentric nozzle rings equally spaced at an interval of ΔR. 
     
     
         5 . The air-bearing chuck according to  claim 4 , wherein a radius of a nozzle ring, farthest from the center of the air-bearing chuck, of the plurality of concentric nozzle rings is 0 mm-20 mm smaller than a radius of the air-bearing chuck. 
     
     
         6 . The air-bearing chuck according to  claim 4 , wherein each support force nozzle and an adjacent opening that are on any one of the plurality of concentric nozzle rings are tangentially spaced at a constant distance ΔT. 
     
     
         7 . The air-bearing chuck according to  claim 6 , wherein as a distance between per nozzle ring of the plurality of concentric nozzle rings and the center of the air-bearing chuck increases, a total number of nozzles on per nozzle ring increases in an even number, and the even number comprises any one of 2, 4, 6, 8 and 10. 
     
     
         8 . The air-bearing chuck according to  claim 6 , wherein a difference between ΔR and ΔT is less than 5 mm. 
     
     
         9 . The air-bearing chuck according to  claim 2 , wherein the plurality of openings comprise a plurality of suction force nozzles, the gas channel portion further comprises a second gas channel, and the second gas channel is configured to transmit a second gas to the plurality of suction force nozzles to provide suction force. 
     
     
         10 . The air-bearing chuck according to  claim 9 , wherein a plurality of first gas through holes corresponding to the plurality of support force nozzles are disposed on both the nozzle portion and the gas channel portion, and a plurality of second gas through holes corresponding to the plurality of openings are disposed on both the nozzle portion and the gas channel portion, the first gas channel is connected to the plurality of support force nozzles through the plurality of first gas through holes, and the second gas channel is connected to the plurality of openings through the plurality of second gas through holes. 
     
     
         11 . The air-bearing chuck according to  claim 9 , wherein the first gas channel comprises a first annular channel and a plurality of first channels connected to the first annular channel, and the second gas channel comprises a second annular channel and a plurality of second channels connected to the second annular channel. 
     
     
         12 . The air-bearing chuck according to  claim 9 , wherein the gas channel portion comprises a first gas layer and a second gas layer that are stacked, the first gas channel is located in the first gas layer, and the second gas channel is located in the second gas layer. 
     
     
         13 . The air-bearing chuck according to  claim 12 , wherein the first gas layer is provided with a first groove for accommodating the first gas channel, and the second gas layer is provided with a second groove for accommodating the second gas channel. 
     
     
         14 . The air-bearing chuck according to  claim 9 , further comprising:
 an air pressure regulator, configured to regulate a flow rate of a gas in each of the first gas channel and the second gas channel to hold a wafer at a predetermined distance from the top surface of the nozzle portion, so as to measure a geometry of the wafer, wherein the geometry of the wafer comprises one or more of a flatness and a shape of the wafer.   
     
     
         15 . The air-bearing chuck according to  claim 14 , further comprising:
 a controller, configured to control the air pressure regulator to regulate the flow rate of the gas in each of the first gas channel and the second gas channel to hold the wafer at the predetermined distance from the top surface of the nozzle portion, so as to measure the geometry of the wafer.   
     
     
         16 . The air-bearing chuck according to  claim 15 , wherein the predetermined distance ranges from 0 μm to 50 μm when the air-bearing chuck is configured to measure the flatness of the wafer. 
     
     
         17 . The air-bearing chuck according to  claim 15 , wherein the predetermined distance ranges from 60 μm to 1500 μm when the air-bearing chuck is configured to measure the shape of the wafer. 
     
     
         18 . The air-bearing chuck according to  claim 2 , wherein the plurality of openings comprise a plurality of flow guide holes, the plurality of flow guide holes are configured to guide the first gas ejected from the plurality of support force nozzles to flow back to the nozzle portion when the first gas encounters the wafer, the gas channel portion further comprises a third gas channel, and the third gas channel is configured to make the first gas that has flowed back to the nozzle portion flow out of the air-bearing chuck. 
     
     
         19 . The air-bearing chuck according to  claim 1 , wherein the air-bearing chuck has a mirror polished surface higher than or equal to level N4 in accordance with an ISO standard. 
     
     
         20 . The air-bearing chuck according to  claim 1 , wherein a material of the nozzle portion comprises any one of aluminum, glass, microcrystalline silicon and ceramic, the material is mirror polished, and the top surface, obtained after being polished, of the nozzle portion is sufficiently flat, so that interference fringes are shown on the top surface of the nozzle portion.