To provide an advanced masking method for semiconductor production, which is useful for treating a large size substrate and an organic material.

An apparatus and a method for restraining a shadow mask against a work piece using attractive force are provided. Specific embodiments in which the shadow mask is restrained against a substrate using both magnetic force and electrostatic force are described. This invention realizes the use of masks that would otherwise be difficult to flatten against a substrate. The invention has the advantage of being useful for much larger shadow masks than conventional ones, and realizes masking of large substrates that are incompatible with wet chemical processing.