Method and apparatus for monitoring a polishing surface of a polishing pad used in polishing apparatus

A method of monitoring a polishing surface of a polishing pad for use in a polishing apparatus, said method comprising:

• conditioning the polishing surface of the polishing pad by causing a rotating dresser to oscillate on the polishing surface;
• measuring a height of the polishing surface at a measuring point while said conditioning of the polishing surface is performed;
• calculating a position of the measuring point of the height on a two-dimensional surface defined on the polishing surface;
• repeating said measuring of the height and said calculating of the position of the measuring point to create a height distribution of the polishing surface;
• creating a distribution of irregular detected points of the height of the polishing surface from the height distribution;
• calculating from the distribution of the irregular detected points an irregularity occurrence density of the height of the polishing surface in plural regions defined in advance on the polishing surface;
• and
• determining that said conditioning of the polishing pad is not performed properly when the irregularity occurrence density in at least one of the plural regions has reached a predetermined threshold value.

A method of monitoring a polishing surface of a polishing pad for use in a polishing apparatus, said method comprising:

• conditioning the polishing surface of the polishing pad by causing a rotating dresser to oscillate on the polishing surface;
• measuring a height of the polishing surface at a measuring point while said conditioning of the polishing surface is performed;
• calculating a position of the measuring point of the height on a two-dimensional surface defined on the polishing surface;
• repeating said measuring of the height and said calculating of the position of the measuring point to create a height distribution of the polishing surface;
• arranging multiple measured values of the height of the polishing surface along a measurement temporal axis to create a measurement waveform that is composed of the multiple measured values;
• creating a monitoring waveform by extracting from the measurement waveform an pulse component which is generated due to rotation of the dresser,
• plotting irregular detected points of the height of the polishing surface onto the two-dimensional surface in a position corresponding to a measured value which is obtained when an amplitude of the monitoring waveform exceeds a predetermined value to create a distribution of the irregular detected points;
• and
• evaluating said conditioning of the polishing pad based on the distribution of the irregular detected points.

A method of monitoring a polishing surface of a polishing pad for use in a polishing apparatus, said method comprising:

• conditioning the polishing surface of the polishing pad by causing a rotating dresser to oscillate on the polishing surface;
• measuring a height of the polishing surface at a measuring point while said conditioning of the polishing surface is performed;
• calculating a position of the measuring point of the height on a two-dimensional surface defined on the polishing surface;
• repeating said measuring of the height and said calculating of the position of the measuring point to create a height distribution of the polishing surface;
• calculating an amount of change in measured value of the height of the polishing surface per predetermined time;
• plotting irregular detected points of the height of the polishing surface onto the two-dimensional surface in a position corresponding to a measured value which is obtained when the amount of change exceeds a predetermined threshold value to create a distribution of the irregular detected points;
• and
• evaluating said conditioning of the polishing pad based on the distribution of the irregular detected points.

An apparatus for monitoring a polishing surface of a polishing pad for use in a polishing apparatus, said apparatus comprising:

• a rotatable dresser configured to condition the polishing surface of the polishing pad while oscillating on the polishing surface;
• a pad height sensor configured to measure a height of the polishing surface at a plurality of different measuring points while conditioning of the polishing surface is performed to obtain measured values of the height;
• and
• a pad monitoring device configured to monitor the polishing pad, said pad monitoring device including:
• a position calculator configured to calculate a position of each of the plurality of different measuring points on a two-dimensional surface defined on the polishing surface, said pad monitoring device being configured to associate the calculated position of each of the plurality of different measuring points with a corresponding one of the measured values of the height to obtain associated positions;
• a pad height analyzer configured to create a height distribution of the polishing surface from the measured values of the height and the associated positions;
• and
• an irregular point distribution generator configured to create a distribution of irregular detected points of the height of the polishing surface from the height distribution, said irregular point distribution generator being further configured to evaluate conditioning of the polishing pad based on the distribution of the irregularity detected points.

An apparatus for monitoring a polishing surface of a polishing pad for use in a polishing apparatus, said apparatus comprising:

• a rotatable dresser configured to condition the polishing surface of the polishing pad while oscillating on the polishing surface;
• a pad height sensor configured to measure a height of the polishing surface at a measuring point while conditioning of the polishing surface is performed;
• a position calculator configured to calculate a position of the measuring point of the height on a two-dimensional surface defined on the polishing surface;
• a pad height analyzer configured to create a height distribution of the polishing surface from a measured value of the height of the polishing surface and the position of the measuring point;
• and
• an irregular point distribution generator configured to create a distribution of irregular detected points of the height of the polishing surface from the height distribution, said irregular point distribution generator being configured to:
• calculate from the distribution of the irregular detected points an irregularity occurrence density of the height of the polishing surface in plural regions defined in advance on the polishing surface;
• and
• determine that conditioning of the polishing pad is not performed properly when the irregularity occurrence density in at least one of the plural regions has reached a predetermined threshold value.

An apparatus for monitoring a polishing surface of a polishing pad for use in a polishing apparatus, said apparatus comprising:

• a rotatable dresser configured to condition the polishing surface of the polishing pad while oscillating on the polishing surface;
• a pad height sensor configured to measure a height of the polishing surface at a measuring point while conditioning of the polishing surface is performed;
• a position calculator configured to calculate a position of the measuring point of the height on a two-dimensional surface defined on the polishing surface;
• a pad height analyzer configured to create a height distribution of the polishing surface from a measured value of the height of the polishing surface and the position of the measuring point;
• and
• an irregular point distribution generator configured to create a distribution of irregular detected points of the height of the polishing surface from the height distribution, said irregular point distribution generator being configured to:
• arrange multiple measured values of the height of the polishing surface along a measurement temporal axis to create a measurement waveform composed of the multiple measured values;
• create a monitoring waveform by extracting from the measurement waveform a pulse component which is generated due to rotation of said dresser;
• create the distribution of the irregular detected points by plotting the irregular detected points onto the two-dimensional surface in a position corresponding to a measured value which is obtained when an amplitude of the monitoring waveform exceeds a predetermined value;
• and
• evaluate conditioning of the polishing pad based on the distribution of the irregular detected points.

An apparatus for monitoring a polishing surface of a polishing pad for use in a polishing apparatus, said apparatus comprising:

• a rotatable dresser configured to condition the polishing surface of the polishing pad while oscillating on the polishing surface;
• a pad height sensor configured to measure a height of the polishing surface at a measuring point while conditioning of the polishing surface is performed;
• a position calculator configured to calculate a position of the measuring point of the height on a two-dimensional surface defined on the polishing surface;
• a pad height analyzer configured to create a height distribution of the polishing surface from a measured value of the height of the polishing surface and the position of the measuring point;
• and
• an irregular point distribution generator configured to create a distribution of irregular detected points of the height of the polishing surface from the height distribution, said irregular point distribution generator being configured to:
• calculate an amount of change in the measured value of the height of the polishing surface per predetermined time;
• create the distribution of the irregular detected points by plotting the irregular detected points onto the two-dimensional surface in a position corresponding to a measured value which is obtained when the amount of change exceeds a predetermined threshold value;
• and
• evaluate conditioning of the polishing pad based on the distribution of the irregular detected points.