Scanning apparatus, for producing masks for micro circuits

In a device for mechanically scanning a surface (14) on which a mask pattern is adapted to be generated in the manufacture of micro circuits, having a source of radiation (31), a radiation sensitive medium on said surface, a first slide (11) carrying said surface, a drive device (23) for reciprocating the first slide in one direction, a second slide (12), means (13) carried by the second slide for transmitting radiation from said source to the radiation sensitive medium on said surface, and drive means connected to the second slide for reciprocation thereof in another direction to scan said surface, comprising means mounting the second slide for mechanical vibration at a natural frequency, pulsing means (9) operating at said natural frequency and elastically coupled continuously to the second slide for maintaining said reciprocation of the second slide at an adjusted amplitude, signal generator means (4) connected to the pulsing means for drive thereof at said natural frequency of the second slide, sensing means for measuring the period of reciprocation of the second slide, and feedback control means connecting the sensing means to the signal generator means for maintaining said reciprocation of the second slide at the adjusted amplitude.