(under subclass 34) Subject matter restricted to the mask itself which is made up of adjacent areas of X-ray opaque and
X-ray transparent material arranged in a selected pattern (usually of an electronic circuit) and used for X-ray lithos:graphic production of plural copies of the pattern.
(1) Note. Although this subclass is restricted to single elements, it is placed here in the schedule as an exception to the general rule of hierarchy since the element described is used only in the system of the parent subclass.
SEE OR SEARCH CLASS
216, Etching a Substrate: Processes,
12, for nonetch function mask involving etching.
430, Radiation Imagery Chemistry: Process, Composition, or Product Thereof,
