DEVICE AND METHOD FOR MOISTENING A POLISHING PAD

Abstract

The present invention relates to a device for moistening a polishing pad. The moistening device comprises measuring means for measuring a physical quantity that is indicative of the moisture in the polishing pad, and dispensing means for dispensing a polishing suspension, based on a value of the measured physical quantity, on a surface of the polishing pad. The measuring means and the dispensing means, are enclosed by a housing having a contact surface for contacting the surface of the polishing pad. The present invention also relates to a device for polishing a specimen and a method for moistening a polishing pad.

Claims

1. A device for moistening a polishing pad, comprising: measuring means for measuring a physical quantity that is indicative of the moisture in the polishing pad, and dispensing means for dispensing a polishing suspension, based on a value of the measured physical quantity, on a surface of the polishing pad, characterised in that the device comprises: a housing that encloses the measuring means and the dispensing means, the housing having a contact surface for contacting the surface of the polishing pad.

2. The device according to claim 1, characterised in that the housing is essentially cylindrical.

3. The device according to claim 1, characterised in that the physical quantity is the resistance on the polishing pad.

4. The device according to claim 3, characterised in that the measuring means comprises two electrical contact elements arranged on the contact surface and a measuring instrument that is configured to measure the resistance between the two electrical contact elements.

5. The device according to claim 3, characterised in that the dispensing means is configured to dispense the polishing suspension on the surface of the polishing pad if the value of the resistance is larger than a first threshold value.

6. The device according to claim 1, characterised in that the physical quantity is the capacitance between opposite sides of the polishing pad.

7. The device according claim 6, characterised in that the measuring means comprises an electrical contact element arranged on the contact surface and a measuring instrument that is configured to measure the capacitance between the electrical contact element and a polishing platen on which the polishing pad is placed.

8. The device according to claim 6, characterised in that the dispensing means is configured to dispense the polishing suspension on the surface of the polishing pad if the value of the capacitance is smaller than a second threshold value.

9. The device according to claim 1, characterised in that the dispensing means comprises a container for holding the polishing suspension and a hose having a first end connected to the container and a second end arranged in connection with the contact surface.

10. The device according to claim 9, characterised in that the dispensing means comprises a nozzle connected to the second end of the hose.

11. The device according to claim 10, characterised in that the dispensing means comprises a valve or a micropump arranged in connection with the container, the hose or the nozzle, and a control unit that is configured to control the operation of the valve or the micropump.

12. The device according to claim 1, characterised in that the device comprises a power source for supplying electrical power to the measuring means and the dispensing means.

13. A device for polishing a specimen, comprising: a polishing platen rotatable about an axis, a polishing pad attached to the polishing platen, and a specimen holder comprising a plurality of specimen cavities for holding one or more specimens against a surface of the polishing pad, characterised in that the device comprises: a device according to any of the preceding claims inserted into one of the specimen cavities so that the contact surface is in contact with the surface of the polishing pad.

14. The device according to claim 13, characterised in that the specimen holder comprises pressing means for pressing the contact surface against the surface of the polishing pad.

15. A method for moistening a polishing pad, characterised in that the method comprises: arranging a device according claim 1 to in a specimen cavity of a specimen holder, arranging the contact surface of the device in contact with a surface of a polishing pad that is attached to a polishing platen, rotating the polishing platen about an axis, measuring with the device a physical quantity that is indicative of the moisture in the polishing pad, and dispensing with the device a polishing suspension, based on a value of the measured physical quantity, on the surface of the polishing pad.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] FIG. 1 illustrates a schematic cross-sectional view of a moistening device according to an embodiment of the invention, and

[0048] FIG. 2 illustrates a schematic side view of a polishing device according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0049] FIG. 1 illustrates a schematic cross-sectional view of a moistening device according to an embodiment of the invention. The moistening device 100 can be used for moistening a polishing pad (not shown in FIG. 1).

[0050] The moistening device 100 comprises a cylindrical housing 101 that is dimensioned in such a manner that the moistening device 100 fits into a specimen cavity of a specimen holder (not shown in FIG. 1). The housing 101 comprises a contact surface 102 that is meant to be arranged in contact with a surface of the polishing pad.

[0051] The moistening device 100 comprises electrical contact elements 103, 104 and 105, which are arranged at the contact surface 102. The electrical contact elements 103, 104 and 105 are electrically connected with wires 106, 107 and 108 to a measuring instrument 109. The measuring instrument 109 can measure the resistance between the electrical contact elements 103 and 104, and the capacitance between the electrical contact element 105 and a polishing platen (not shown in FIG. 1) on which the polishing pad is placed. The resistance between the electrical contact elements 103 and 104, and the capacitance between the electrical contact element 105 and the polishing platen are indicative of the moisture in the polishing pad. A wire 110 is used to electrically connect the measuring instrument 109 to the polishing platen. For the measurement of the resistance and/or the capacitance, the contact surface 102 is arranged in contact with the surface of the polishing pad.

[0052] The moistening device 100 comprises a container 111 for holding a polishing suspension and a hose 112 having its first end connected to the container 111. A second end of the hose 112 is connected to a nozzle 113 that is arranged at the contact surface 102. The hose 112 is provided with a valve 114 that controls the flow of the polishing suspension from the container 111 to the surface of the polishing pad. The moistening device 100 comprises a control unit 115 that controls the operation of the valve 114. The control unit 115 controls the valve 114 to dispense a suitable amount of the polishing suspension on the surface of the polishing pad. The amount of the polishing suspension to be dispensed is determined based on the value of the measured resistance or the capacitance. The control unit 115 receives the value of the measured resistance or the capacitance from the measuring instrument 109.

[0053] The moistening device 100 comprises a transceiver 116 for bidirectional wireless communications with a remote device (not shown in FIG. 1). The transceiver 116 enables to remotely control the operation of the moistening device 100. The moistening device 100 comprises a battery 117 for supplying electrical power to the measuring instrument 109, the control unit 115, and the transceiver 116.

[0054] FIG. 2 illustrates a schematic side view of a polishing device according to an embodiment of the invention. The polishing device 200 can be used for polishing specimens.

[0055] The polishing device 200 comprises a polishing platen 201 that can be rotated about an axis with an actuator 202. A polishing pad 203 is attached to the polishing platen 201. The polishing pad 203 is used for polishing a specimen 204 that is held against the polishing pad 203 with a specimen holder 205. The specimen 204 is arranged in a specimen cavity 206 of the specimen holder 205. The specimen holder 205 can be rotated about an axis, which is parallel to the rotation axis of the polishing platen 201, with an actuator 207. As the polishing platen 201 and the specimen holder 205 are rotated, the polishing pad 203 polishes the specimen 204.

[0056] The polishing device 200 comprises a moistening device 100 according to FIG. 1. The moistening device 100 is arranged in a specimen cavity 208 of the specimen holder 205 in such a manner that the contact surface 102 of the moistening device 100 is in contact with the surface of the polishing pad 203. The moistening device 100 measures the resistance or the capacitance indicative of the moisture in the polishing pad 203 and, based on the value of the measured resistance or the capacitance, dispenses the polishing suspension on the surface of the polishing pad 203. For the capacitance measurement, a wire 209 is used to electrically connect the polishing platen 201 to the moistening device 100.

[0057] Only advantageous exemplary embodiments of the invention are described in the figures. It is clear to a person skilled in the art that the invention is not restricted only to the examples presented above, but the invention may vary within the limits of the claims presented hereafter. Some possible embodiments of the invention are described in the dependent claims, and they are not to be considered to restrict the scope of protection of the invention as such.