Apparatus for uniform chemical mechanical polishing by intermittent lifting and reversible rotation

An apparatus for polishing a sample having a surface to be polished, said apparatus comprising:

• a platen having an upper surface upon which the sample surface is to be polished;
• a sample holder disposed opposite to said platen's upper surface, wherein at least one of the platen and the sample holder is rotatable about a first axis to effect polishing;
• a positioning means for changing the vertical distance between the sample holder and the platen in response to a control signal, said positioning means being capable of changing the vertical distance between a first value which brings the sample in contact with the platen, and a second value which separates the sample from contact with the platen;
• and
• a controller for generating said control signal during a polishing cycle, wherein said controller generates said control signal to cause said positioning means to change said vertical distance intermittently in a range between said first and second values during said polishing cycle such that the sample is separated from contact with the platen at a plurality of times during said polishing cycle.

An apparatus for polishing a sample having a surface to be polished, said apparatus comprising:

• a platen having an upper surface upon which the sample surface is to be polished;
• a sample holder disposed opposite to said platen's upper surface;
• a first motor drive assembly which rotates one of the platen and the sample holder about a first axis to effect polishing, said first motor drive assembly being responsive to a direction control signal having a first state to indicate a clockwise rotation and a second state to indicate a counter-clockwise rotation, and wherein said first motor assembly rotates said one of the platen and the sample holder in the clockwise direction when said direction control signal is in its first state, and in the counter-clockwise direction when said direction control signal is in its second state;
• a controller for generating said direction control signal during a polishing cycle, wherein said controller generates said direction control signal to cause said first motor drive assembly to intermittently change rotational directions during said polishing cycle.

An apparatus for polishing a sample having a surface to be polished, said apparatus comprising:

• a platen having an upper surface;
• and
• a sample holder disposed opposite to said platen's upper surface, wherein one of the platen and the sample holder is rotated with respect to the other;
• and
• wherein the direction of rotation of one of the platen and the sample holder is varied a plurality of times during a polishing cycle.

In a apparatus for polishing a sample having a surface to be polished, said apparatus comprising a platen having an upper surface, a sample holder disposed opposite to said platen's upper surface, a positioner which moves the sample holder between a first position which brings the sample in contact with the platen and a second position which separates the sample from contact with the platen in response to a control signal, a controller comprising:

• an output port capable of providing a control signal to the positioner;
• a memory for holding a sequence of position instructions and corresponding time periods to be used to direct the operation of the positioner between said first and second positions during a polishing cycle, a plurality of said instructions directing the positioner to separate the sample from contact with the platen at a plurality of times during said polishing cycle;
• a timer providing an electronic signal representative of time;
• and
• a processing unit which generates control signals at said output port in response to the sequence contents of said memory and the output of said timer.

In an apparatus for polishing a sample having a surface to be polished, said apparatus comprising a platen having an upper surface, a sample holder disposed opposite to said platen's upper surface, a motor assembly for rotating one of the sample holder and the platen in either of two directions, the direction being selectable in response to a control signal;

• a controller comprising:
• an output port capable of providing a control signal to the apparatus for the motor assembly;
• a memory for holding a sequence of rotation directions and corresponding time periods to be used to direct the operation of the motor assembly by said controller;
• a timer providing an electronic signal representative of time;
• and
• a processing unit which generates control signals at said output port in response to the sequence contents of said memory and the output of said timer.