Polishing apparatus

1. A polishing apparatus comprising:

a polishing table for supporting a polishing pad;

a polishing head configured to press a wafer against the polishing pad;

a light-source assembly;

a light-emitting transmission line having a distal end located at a predetermined position in the polishing table;

a light-receiving transmission line having a distal end located at the predetermined position in the polishing table;

a spectrometer coupled to the light-receiving transmission line, the spectrometer being configured to decompose reflected light, transmitted from the wafer through the light-receiving transmission line, in accordance with wavelength and measure intensity of the reflected light at each of wavelengths; and

a processor configured to obtain information of a film of the wafer based on a spectral waveform indicating a relationship between intensity and wavelength of the reflected light,

wherein the light-source assembly includes:

a base fixed to the polishing table and coupled to the light-emitting transmission line; and

a light-source module having a lamp for emitting light, the light-source module being removably attached to the base,

the base is a common base which is adapted to any of a plurality of light-source modules of different types including the light-source module, and

the base includes a positioning structure which achieves positioning of the light-source module relative to the base.

2. The polishing apparatus according to claim 1 , wherein the base has an optical path located therein, the optical path has an entrance facing the lamp, and the optical path has an exit coupled to the light-emitting transmission line.

3. The polishing apparatus according to claim 2 , wherein the light-source module has a lamp cover that covers the lamp, the base has a recess formed in an outer surface of the base, and the lamp cover is fitted into the recess.

4. The polishing apparatus according to claim 2 , wherein the positioning structure comprises a plurality of positioning pins or a plurality of positioning pins arranged around the entrance of the optical path.

5. The polishing apparatus according to claim 1 , wherein:

the base includes a power input line, a signal input line, a power output line, a signal output line, and a cable connector coupled to the power output line and the signal output line, and

the light-source module includes a connector port which can be coupled to the cable connector.

6. The polishing apparatus according to claim 1 , wherein:

the base includes a hook; and

the light-source module includes an engagement member located right above the hook.

7. The polishing apparatus according to claim 1 , wherein:

the light-source module comprises a first light-source module having a first lamp configured to emit light;

the polishing apparatus further includes a second light-source module having a second lamp configured to emit light having a wavelength range different from that of the first lamp; and

one of the first light-source module and the second light-source module is selectively attached to the base.