Method of supporting wafer, wafer supporting apparatus and wafer mounter having the apparatus

Claim 1

In a method of supporting a wafer having a front side and a back side comprising the steps of setting the wafer and an outer frame on a table plate with the front side of said wafer toward the table plate within the outer frame, pressing and applying a tape to the back side of each wafer and the outer frame by means of a roller while sucking a peripheral portion of the wafer towards the table plate, and producing a supporting back-up pressure on the front side of the wafer by means of compressed air, said method further comprising the steps of: forming said table plate (20) to include a main body (20a) of circular shape; forming a central recess in an upper surface of said table plate; inserting and fixing a central member (20b) in said central recess which is bounded by a pressure setting wall (29) which projects from the recess in the table plate to a position in a vicinity of the front side of the wafer; forming a peripheral member (20c) of said main body; forming a first pressure space between said central member in said table plate and a center portion of the front side of the wafer on the table plate and said first pressure space is confined by said pressure setting wall (29); forming a second pressure space between said peripheral member (20c), the pressure setting wall (29) and the front side of the wafer on the table plate; forming a throttle passage between said pressure setting wall and said front side of said wafer which throttles compressed air from said first pressure space to said second pressure space; producing a desired supporting pressure of said compressed air in said first pressure space and on a front side of the wafer, which is supplied from a compressed air source to the first pressure space; by means of a throttling function of said throttle passage formed between the pressure setting wall and the front side of the wafer, producing a further desired supporting pressure of said compressed air in said second pressure space which is supplied from the first pressure space to the second pressure space through the throttle passage, and by means of a throttling function of a throttle opening in said second pressure space, said second pressure space being connected with the atmosphere.