Apparatus and methods for controlling pad conditioning head tilt for chemical mechanical polishing

Apparatus for conditioning a chemical mechanical polishing pad having an axis of rotation, the apparatus comprising:

• a conditioning puck having a puck axis;
• a chuck for urging the conditioning puck against the pad with the puck axis parallel to and displaced from the axis of rotation, the pad providing a conditioning force that is eccentric with respect to the puck axis;
• and
• a chuck support configured to resist a tilting force on the chuck resulting from the eccentric conditioning force.

Apparatus for conditioning a pad of a chemical mechanical polishing unit, comprising:

• a chuck configured with a fluid port and a manifold for distributing fluid from the port completely across a surface of the chuck;
• a pad conditioning puck carried on the surface of the chuck, the puck having a puck axis of rotation and a configuration substantially completely covering the surface of the chuck, the puck being fabricated from material having perforations across substantially all of the configuration of the puck, the puck being further fabricated with a sheet secured to the puck, the sheet having an upper surface, the sheet being substantially completely provided with holes that are smaller than the perforations;
• a main housing secured to the chuck for rotating the chuck, the housing being provided with a through hole;
• and
• a conduit extending through the through hole and connected to the fluid port for supplying the fluid to the manifold of the chuck for flow through the perforations and the holes to clean the puck.

A method for controlling relative movement between a pad conditioning puck and a chemical mechanical polishing pad, comprising the operations of:

• mounting the puck on a chuck, the puck having an axis of symmetry;
• offsetting in parallel relationship an axis of rotation of the pad and the axis of symmetry of the mounted puck;
• urging the pad and the offset mounted puck toward each other parallel to the axis of rotation and to the axis of symmetry to cause the pad to impose a conditioning force on the mounted puck eccentrically with respect to the axis of symmetry, in response to the conditioning force the puck having a tendency to tilt such that the axis of symmetry tends to move out of the parallel relationship with the axis of rotation;
• and
• during the urging operation resisting the tendency of the mounted offset puck to tilt while allowing the puck to move parallel to a direction of the axis of rotation.

A method for controlling relative movement between a chemical mechanical polishing pad and a pad conditioning puck, comprising the operations of:

• mounting the puck on a chuck, the puck having an axis of symmetry parallel to an axis of rotation of the pad, the puck having a surface positioned by the chuck parallel to a polishing surface of the pad, the pad having an axis of rotation;
• offsetting the axis of rotation of the pad from the axis of symmetry of the mounted puck with the axes parallel to define an initial orientation of the puck;
• providing a chuck support plate for resisting movement of the polishing surface of the pad and the surface of the puck toward each other, the chuck being movable relative to the chuck support plate;
• providing the chuck and the chuck support plate with a plurality of pairs of linear bearing assemblies, each of the assemblies having a housing provided with a bearing axis perpendicular to the polishing surface of the pad and parallel to the initial orientation of the axis of symmetry, each of the assemblies having a linear shaft received in a respective one of the housings, the assemblies being between the chuck and the chuck support plate;
• using the chuck support plate to cause the mounted puck to resist the movement of the polishing surface of the pad and the surface of the puck toward each other, the pad imposing a conditioning force on the surface of the mounted puck eccentrically with respect to the axis of symmetry, in response to the eccentric conditioning force the chuck and the mounted puck having a tendency to tilt such that the surface of the puck tends to move from the initial orientation and out of parallel with the polishing surface of the pad;
• and
• during the using of the chuck support plate the assemblies being effective to limit movement of the chuck relative to the chuck support plate to movement parallel to the axis of symmetry so that the surface of the puck remains parallel to the polishing surface.

A method of purging a puck for conditioning a chemical mechanical polishing pad, comprising the operations of:

• perforating the puck to provide openings in the puck through which a fluid may flow;
• providing a puck carrier having a puck support surface and a lip at a peripheral edge, the puck carrier being configured to spread the fluid substantially completely across the puck support surface, the fluid having a depth determined by a height of the lip above the puck support surface;
• mounting the puck carrier on a supporthead for positioning the puck with the puck support surface oriented horizontally and the lip extending upwardly from the support surface;
• forming a port through the puck carrier to the puck support surface;
• and
• supplying the fluid through the puck carrier to the port to enable the puck carrier configuration to spread the fluid substantially completely across the puck support surface within the lip to immerse the puck in the fluid, the supplying causing the fluid to flow over the lip and purge the puck.

A method for controlling relative movement between a chemical mechanical polishing pad and a pad conditioning puck, comprising the operations of:

• mounting the puck on a chuck, the puck having an axis of symmetry perpendicular to a polishing surface of the pad and a conditioning surface parallel to the polishing surface, the pad having an axis of rotation;
• offsetting the axis of rotation of the pad from the axis of symmetry of the mounted puck with the axes parallel to define an initial orientation of the puck;
• moving the polishing surface of the pad and the conditioning surface of the puck toward each other, the conditioning surface of the mounted puck resisting the polishing surface of the pad, the pad imposing a conditioning force on the mounted puck eccentrically with respect to the axis of symnmetry, in response to the conditioning force the chuck and the mounted puck having a tendency to tilt such that the conditioning surface tends to move from the initial orientation and out of parallel with the polishing surface;
• and
• providing an array of pairs of linear bearing assemblies adjacent to the mounted puck, during the moving operation the assemblies being effective to substantially limit movement from the initial orientation and permit only movement of the mounted puck with the conditioning surface parallel to the polishing surface.