Use of variable impedance having rotating core to control coil sputter distribution

A semiconductor fabrication system, comprising:

• a semiconductor fabrication chamber having a plasma generation area within said chamber;
• a plasma generation coil positioned to couple RF energy into said plasma generation area to maintain a plasma in said plasma generation area, said plasma generation coil having a plurality of voltage values distributed along said coil;
• and
• reactance means coupled to said coil and having a first inductor coil which defines a central axis, and a first rotating core positioned within said inductor coil and adapted to rotate about a rotational axis which is nonparallel to said inductor coil central axis, for shifting said distribution of voltage values in a predetermined path along said plasma generation coil.

A semiconductor fabrication system, comprising:

• a semiconductor fabrication chamber having a plasma generation area within said chamber;
• a plasma generation coil positioned to couple RF energy into said plasma generation area to maintain a plasma in said plasma generation area, said plasma generation coil having a plurality of voltage values distributed along said plasma generation coil;
• a first inductor coupled between said plasma generation coil and ground wherein said first inductor includes a first inductor coil having a central axis and a first rotating core adapted to rotate about a rotational axis which is nonparallel to said first inductor coil central axis;
• and
• core rotation means for rotating said first inductor core about said core rotation axis and thereby changing the inductance of said first inductor so as to shift said voltage value distribution in a predetermined path along said plasma generation coil.

A semiconductor fabrication system for use with an RF generator, comprising:

• a semiconductor fabrication chamber having a plasma generation area within said chamber;
• a plasma generation coil positioned to couple RF energy into said plasma generation area to maintain a plasma in said plasma generation area, said plasma generation coil having a first end and a second end wherein said first end is adapted to be coupled to said RF generator;
• a first variable inductor coupled between said plasma generation coil second end and ground, said first inductor having a first variable inductance and comprising a first inductor coil having a central axis, and a first core adapted to rotate within said first inductor about an axis nonparallel to said first inductor coil central axis to provide said first variable inductance which varies as a function of the position of said first core as said first core rotates;
• and
• a second variable inductor adapted to be coupled between said plasma generation coil first end and said RF generator, said second inductor having a second variable inductance and comprising a second inductor coil having a central axis, and a second core adapted to rotate within said second inductor about an axis nonparallel to said second inductor coil central axis to provide said second variable inductance which varies as a function of the position of said second core as said first core rotates, said second core being mechanically coupled to said first core so that said first and second cores rotate in unison.

A semiconductor fabrication process for sputtering material onto a substrate, the process comprising:

• placing a substrate in a semiconductor fabrication chamber having a plasma generation area within said chamber;
• energizing a target of said material to sputter said material from said target;
• energizing a plasma generation coil carried by said semiconductor fabrication chamber and positioned to couple RF energy into said plasma generation area to ionize said sputtered target material to form a layer of said sputtered target material on said substrate;
• and
• rotating a first core of a first inductor coil coupled to said plasma generation coil, so as to shift a voltage distribution in a predetermined path along said plasma generation coil to time-average voltage distributions along said plasma generation coil wherein said first core is adapted to rotate about a rotational axis which is nonparallel to a first inductor coil central axis.

A semiconductor fabrication process comprising:

• placing a substrate in a semiconductor fabrication chamber adjacent a plasma generation area within said chamber;
• energizing a plasma generation coil positioned to couple RF energy into said plasma generation area to maintain a plasma in said plasma generation area adjacent said workpiece and to generate ions to process said workpiece;
• and
• rotating a first core of a first inductor coil coupled to said plasma generation coil so as to shift a voltage value distribution in a predetermined path along said plasma generation coil wherein said first core is adapted to rotate about a rotational axis which is nonparallel to a first inductor coil central axis.

A semiconductor fabrication process, comprising:

• placing a substrate in a semiconductor fabrication chamber adjacent a plasma generation area within said chamber;
• energizing a plasma generation coil positioned to couple RF energy into said plasma generation area to maintain a plasma in said plasma generation area adjacent said workpiece and to generate ions to process said workpiece, said plasma generation coil having a plurality of voltage values distributed along said plasma generation coil;
• and;
• cyclicly rotating a core of an inductor about a rotational axis which is nonparallel to a central axis of said inductor, to cyclicly shift said distribution of voltages along said plasma generation coil.