Method and apparatus for holding substrate

An apparatus for holding a substrate, comprising:

• a table;
• a lifting and lowering mechanism configured to mount a substrate on said table;
• at least one pressing member configured to press the substrate toward said table from the peripheral side of the substrate, said pressing member being movable upward and downward;
• at least one detector configured to detect a warp of the substrate mounted on said table;
• and
• a controller configured to control a movement of said pressing member, said controller changing a starting position of said pressing member for pressing the substrate in accordance to the content of the warp.

A laser processing unit, comprising:

• a table;
• a lifting and lowering mechanism configured to mount a substrate on said table;
• at least one pressing member configured to press the substrate toward said table from the peripheral side of the substrate, said pressing member being movable upward and downward;
• at least one detector configured to detect a warp of the substrate mounted on said table from the peripheral side of the substrate;
• and
• a controller configured to control a movement of said pressing member in accordance to the detected warp.

An exposure unit, comprising:

• a table;
• a lifting and lowering mechanism configured to mount a substrate on said table;
• at least one pressing member configured to press the substrate toward said table from the peripheral side of the substrate, said pressing member being movable upward and downward;
• at least one detector configured to detect a warp of the substrate mounted on said table from the peripheral side of the substrate;
• and
• a controller configured to control a movement of said pressing member in accordance to the detected warp.

A method for holding a substrate, comprising:

• mounting a substrate on a table by a lifting and lowering mechanism;
• detecting a warp of the substrate mounted on said table from the peripheral side of the substrate based on emission and absorption of light;
• pressing the substrate toward said table from the peripheral side of the substrate by a pressing member configured to be movable upward and downward;
• and
• controlling a movement of said pressing member in accordance to the detected warp.

A method for holding a substrate comprising:

• mounting a substrate on a table by a lifting and lowering mechanism;
• detecting a warp of the substrate mounted on said table based on emission and absorption of light;
• pressing the substrate toward said table from the peripheral side of the substrate by a pressing member configured to be movable upward and downward;
• controlling a movement of said pressing member in accordance to the detected warp;
• and
• changing a starting position of said pressing member for pressing the substrate in accordance to the content of the warp.