Contacting method and apparatus in contact copying

Claim 1

A method of bringing a mask and a wafer into intimate contact, said method comprising the steps of: holding a marginal portion of the mask on a mask holder; holding a wafer on a wafer chuck; locating the mask holder and the wafer chuck so that the mask and wafer are out of contact; exhausting gas from between the mask and the wafer while substantially preventing relative movement between the mask holder and the wafer chuck and concurrently permitting atmospheric pressure to act on a surface of the mask at its side opposite to the wafer thereby to cause the mask to become convex relative to the wafer; and thereafter moving the mask holder and the wafer chuck relative to each other thereby to bring the mask and the wafer into intimate contact with each other.

Claim 2

A method of bringing a mask and a wafer into intimate contact, said method comprising the steps of: holding a marginal portion of the mask on a mask holder; holding a wafer on a wafer chuck; locating the mask holder and the wafer chuck so that the mask and wafer are out of contact; exhausting gas from between the mask and the wafer while substantially preventing relative movement between the mask holder and the wafer chuck and concurrently permitting atmospheric pressure to act on a surface of the mask at its side opposite to the wafer thereby to cause the mask to become convex relative to the wafer; and thereafter moving the mask holder and the wafer chuck relative to each other thereby to bring the mask and the wafer into intimate contact with each other.

Claim 3

A method of bringing a mask and a wafer into intimate contact, said method comprising the steps of: holding the mask on a mask holder; holding a marginal portion of the wafer on a wafer chuck; locating the mask holder and the wafer chuck so that the mask and wafer are out of contact; ejecting a pressurized gas onto the central portion of the surface of the wafer opposite to the mask while substantially preventing relative movement between the mask holder and the wafer chuck; exhausting gas from between the mask and the wafer; and thereafter moving the mask holder and the wafer chuck relative to each other to bring the mask and wafer into intimate contact with each other.

Claim 4

A method of bringing a mask and a wafer into intimate contact, said method comprising the steps of: holding the mask on a mask holder; holding a marginal portion of the wafer on a wafer chuck; locating the mask holder and the wafer chuck so that the mask and wafer are out of contact; ejecting a pressurized gas onto the central portion of the surface of the wafer opposite to the mask while substantially preventing relative movement between the mask holder and the wafer chuck; exhausting gas from between the mask and the wafer; and thereafter moving the mask holder and the wafer chuck relative to each other to bring the mask and wafer into intimate contact with each other.