Chemical mechanical polishing temperature scanning apparatus for temperature control
A chemical mechanical polishing apparatus includes a platen having a top surface to hold a polishing pad, a carrier head to hold a substrate against a polishing surface of the polishing pad during a polishing process, and a temperature monitoring system. The temperature monitoring system includes a non-contact thermal sensor positioned above the platen that has a field of view of a portion of the polishing pad on the platen. The sensor is rotatable by the motor around an axis of rotation so as to move the field of view across the polishing pad.
1 . A chemical mechanical polishing apparatus comprising:
a platen that is rotatable about an axis and having a top surface to hold a polishing pad;
a motor to rotate the platen in a first direction;
a support extending over the platen, wherein the support is movable relative to the platen;
a carrier head suspended from and affixed to the support and arranged to hold a substrate against a polishing surface of the polishing pad during a polishing process;
a temperature control system including a dispenser to deliver a temperature controlled fluid onto the polishing pad; and
a temperature monitoring system including a non-contact thermal imaging sensor suspended from and affixed to the support,
wherein the support including the affixed carrier head and the affixed non-contact thermal imaging sensor is configured to move with respect to the platen such that the non-contact thermal imaging sensor is positioned above the platen to have a field of view of a portion of the polishing pad on the platen and wherein the motor rotates the platen and the thermal imaging sensor is positioned such that the field of view is positioned to measure a section of the polishing pad after the section of the polishing pad has passed below the substrate and before the section of the polishing pad passes below the dispenser.
2 . The apparatus of claim 1 , further comprising a controller configured to generate a temperature profile from sensor data captured by the thermal imaging sensor of the portion of the polishing pad on the platen.
3 . The apparatus of claim 2 , wherein the controller is configured to generate the temperature profile from a plurality of temperature measurements captured by the thermal imaging sensor of the polishing pad on the platen.
4 . The apparatus of claim 2 , wherein the controller is configured to adjust operation of one or more of a heater and a cooler in response to the generated temperature profile.
5 . The apparatus of claim 2 , wherein the temperature profile comprises an angular profile about the axis of rotational of the platen.
6 . The apparatus of claim 2 , wherein the temperature profile comprises a radial temperature profile.
7 . The apparatus of claim 2 , further comprising one or more actuators to move the support relative to the platen, and wherein the controller is further configured to operate one or more actuators to control a monitored position of the portion of the polishing pad by the thermal imaging sensor.
8 . A chemical mechanical polishing apparatus comprising:
a platen that is rotatable about an axis and having a top surface to hold a polishing pad;
a support extending over the platen, wherein the support is movable relative to the platen;
a carrier head suspended from and affixed to the support and arranged to hold a substrate against a polishing surface of the polishing pad during a polishing process;
a temperature monitoring system including a non-contact thermal imaging sensor suspended from and affixed to the support, wherein the support including the affixed carrier head and the affixed non-contact thermal imaging sensor is configured to move with respect to the platen such that the non-contact thermal imaging sensor is positioned above the platen to have a field of view of a portion of the polishing pad on the platen; and
a controller configured to generate a temperature profile from sensor data captured by the thermal imaging sensor of the portion of the polishing pad on the platen, and wherein the temperature profile comprises an aggregate temperature of the portion of the polishing pad on the platen.
9 . The apparatus of claim 7 , wherein the thermal imaging sensor is affixed to the support by a sensor support, and wherein the one or more actuators are operable to move the sensor support and thermal imaging sensor along a z-axis to adjust a distance between the thermal imaging sensor and the polishing pad on the platen.
10 . The apparatus of claim 9 , wherein the thermal imaging sensor is affixed to the support by a sensor support, wherein the sensor support is rotatable about an axis of rotation such that the thermal imaging sensor is rotatable to view different portions of the polishing pad on the platen.
11 . The apparatus of claim 10 , wherein the controller is configured to adjust one or more of a rotational and lateral positions of the thermal imaging sensor with respect to the polishing pad on the platen and collect, in two or more positions, temperature measurements to generate the temperature profile.
12 . The apparatus of claim 11 , wherein the controller is configured to receive temperature measurements from the thermal imaging sensor and, in response, operate the one or more actuators to control the monitored position of the portion of the polishing pad on the platen by the thermal imaging sensor.
13 . A chemical mechanical polishing apparatus comprising:
a rotatable platen having an axis of rotation and a top surface to hold a polishing pad;
a carrier head to hold a substrate against a polishing surface of the polishing pad during a polishing process;
a temperature control system including a heater and/or cooler,
a support extending over the platen,
a temperature monitoring system including a non-contact thermal sensor positioned above the platen to have a field of view of a portion of the polishing pad on the platen;
a linear actuator to move the thermal sensor along the support;
a controller coupled to the temperature control system, the temperature monitoring system and the linear actuator and configured to
control the linear actuator so as to cause the thermal sensor to move linearly along the support,
receive a plurality of temperature measurements from thermal sensor at a plurality of positions on the polishing pad,
determine radial positions of the field of view of the thermal sensor relative to the axis of rotation of the platen for the plurality of temperature measurements,
generate a radial temperature profile of the polishing pad using the plurality of temperature measurements and the radial positions, and
adjust operation of the heater and/or cooler based on the radial temperature profile so as to improve temperature uniformity of the polishing pad.
14 . The apparatus of claim 13 , wherein controller is configured to determine the radial positions of the field of view based on the position of the thermal sensor along the support.
15 . The apparatus of claim 14 , wherein controller is configured to determine the radial positions of the field of view based on an angle of the field of view and a vertical distance of the thermal sensor to the polishing pad.
16 . The apparatus of claim 13 , comprising a vertical actuator operable to move the support and the thermal sensor along a z-axis to adjust a distance between the thermal sensor and the polishing pad on the platen.
17 . The apparatus of claim 13 , wherein the thermal sensor comprises an infrared sensor.
18 . The apparatus of claim 13 , wherein the thermal sensor comprises an imaging sensor.
19 . The apparatus of claim 13 , wherein the temperature control system comprises a dispenser to deliver a fluid onto a polishing surface of the polishing pad.
20 . The apparatus of claim 19 , wherein the fluid is a gas to heat the polishing pad.
21 . The apparatus of claim 19 , wherein the fluid is a liquid to cool the polishing pad.
22 . The apparatus of claim 19 , wherein the dispenser comprises an arm extending over the platen and a plurality of individually-controllable nozzles on the arm to deliver the fluid to the polishing surface of the polishing pad.
23 . The apparatus of claim 19 , wherein the dispenser comprises an arm and a rotational actuator to swing the arm laterally over the platen.