Measurement apparatus and method
A method and apparatus for extracting the contents of voids and/or pores present in a semiconductor device to obtain information indicative of the nature of the voids and/or pores, e.g. to assist with metrology measurements. The method includes heating the semiconductor wafer to expel the contents of the voids and/or pores, collecting the expelled material in a collector, and measuring a consequential change in mass of the semiconductor wafer and/or the collector, to extract information indicative of the nature of the voids. This information may include information relating to the distribution of the voids and/or pores, and/or the sizes of the voids and/or pores, and/or the chemical contents of the voids and/or pores. The collector may include a condenser having a temperature-controlled surface (e.g. in thermal communication with a refrigeration unit) for condensing the expelled material.
1. A semiconductor wafer metrology method comprising:
heating a semiconductor wafer to expel material contained in enclosed voids formed in or beneath a layer deposited on the semiconductor wafer;
collecting the expelled material in a collector; and
measuring a consequential change in mass of the semiconductor wafer and/or the collector, to extract information indicative of the nature of the enclosed voids wherein the collector is a condenser having a temperature-controlled surface for condensing the expelled material.
2. A method according to claim 1 , wherein heating the semiconductor wafer comprises applying heat to a surface of the semiconductor wafer opposite to a surface on which the layer is deposited.
3. A method according to claim 1 including positioning the temperature-controlled surface opposite to the surface of the semiconductor wafer on which the layer is deposited in order to collect the expelled material.
4. A method according to claim 1 , wherein the temperature-controlled surface of the condenser is partitioned into a plurality of condensing portions.
5. A semiconductor wafer metrology method comprising:
heating a semiconductor wafer to expel material contained in enclosed voids formed in or beneath a layer deposited on the semiconductor wafer;
collecting the expelled material in a collector; and
measuring a consequential change in mass of the semiconductor wafer and/or the collector, to extract information indicative of the nature of the enclosed voids;
wherein heating the semiconductor wafer comprises gradually increasing the temperature of the semiconductor wafer, and wherein measuring the consequential change in mass of the semiconductor wafer and/or the collector comprises performing a plurality of mass measurement during the increase in temperature to obtain the consequential change in mass of the semiconductor wafer and/or the collector as a function of the temperature of the semiconductor wafer.
6. A semiconductor wafer metrology method comprising:
heating a semiconductor wafer to expel material contained in enclosed voids formed in or beneath a layer deposited on the semiconductor wafer;
collecting the expelled material in a collector;
measuring a consequential change in mass of the semiconductor wafer and/or the collector, to extract information indicative of the nature of the enclosed voids; and
after collecting the expelled material in the collector, applying localized heating to each of a plurality of regions of the collector to expel the collected material in each region, and measuring a consequential change in mass of the collector to extract information indicative of the nature of the collected material.
7. A semiconductor wafer metrology method comprising:
heating a semiconductor wafer to expel material contained in enclosed voids formed in or beneath a layer deposited on the semiconductor wafer;
collecting the expelled material in a collector; and
measuring a consequential change in mass of the semiconductor wafer and/or the collector, to extract information indicative of the nature of the enclosed voids; and
after collecting the expelled material in the collector, applying localized heating to each of a plurality of regions of the collector to expel the collected material in each region, and analyzing the expelled collected material.
8. A method according to claim 7 , wherein analyzing the expelled collected material includes measuring the expelled collected material using a mass spectrometer.