Method for initiating a helium alarm particle detector in a dry etching system prior to initiation of the etching process

DETAILED DESCRIPTION It is an object of this invention to detect particles in a dry etching chamber, prior to initiation of the patterning cycle of the dry etching procedure, with the wafers to be subsequently patterned, present in the dry etching system.
It is another object of this invention to initiate a backside helium alarm procedure during a first cycle of a dry etching procedure, using plasma conditions that allow the helium leak detection procedure to initiate, however without the removal or etching of the exposed portions of metal, not covered by a photoresist shape.
It is still another object of this invention to, after an acceptable dry etching chamber particle count, perform an in situ, second dry etching cycle, using plasma conditions that result in the desired patterning of a metal layer.
In accordance with the present invention a method of detecting particles in a dry etching tool via a backside helium alarm procedure, performed during a non-etching, first cycle of a dry etching procedure, followed by an in situ, second cycle of the dry etching procedure, used to define the desired metal interconnect pattern, is described.
A semiconductor wafer comprised with a photoresist shape, overlying a metal layer, is placed on an electrostatic chuck, (ESC), of a dry etching system, with the wafer overlaying openings in the ESC, where the openings allow subsequent injection of helium to interface with the backside of the semiconductor wafer.
A first cycle of the dry etching procedure, performed using plasma conditions that do not etch the exposed metal layer, is next employed, allowing initiation of the backside helium alarm procedure to be activated.
If the backside helium alarm procedure indicates an absence of particles, an in situ, second cycle of the dry etching procedure is performed at plasma conditions that result in definition of the desired metal pattern.
However if the backside helium alarm indicated particles, the dry etching cycle can be interrupted, followed by: system cleaning; photoresist re-work; and the re-start of the two cycle, dry etching procedure, featuring the backside helium alarm procedure