METHOD OF MAKING PRECISION OPTICAL SCALES USING LIFT-OFF PHOTOLITHOGRAPHY Russian patent published in 2009 - IPC G02B27/00 

FIELD: physics.

SUBSTANCE: method of making a dial from a glass polished work piece involves the following sequence: grease is removed from the work piece using lint-free napkins saturated with organic solvent. The work piece is rotated at 3500 rpm, successively adding a cleaning solution and water. First thermal processing is done on a hot plate (the work piece of the dial is put on the plate with a gap, and when making a scale, for example the work piece is directly in contact with the plate) at 130°C in an enclosed volume in the presence of an adhesive. Positive photoresist based on a diazo-compound is deposited on the work piece, which is rotated at 1000 rpm at the first stage and then unwound at 3500 rpm with deviation of ±10 rpm. Second thermal processing is done in the same way as the first, but without adhesive. Exposure is done on an installation for making topological features with thickness of 1.5 mcm. The developer is placed in the working zone of the work piece, rotating at 3500 rpm. The work piece is then washed with water. A chrome masking coating is deposited on the work piece through vacuum deposition. The protective photoresistive coating is removed using organic solvent. Non-aggressive organic solvents are used in all operations. Air in the room complies with class 5 ISO, GOST ISO 14644-1-2002, and the water used does not contain particles with size greater than 0.2 mcm.

EFFECT: improved technical characteristics and quality of components, cutting on labour input and consumption of material by half, improved safety level of the method with respect to occupational and environmental safety.