Stmicroelectronics S.a.

Luc Liauzu

Emmanuel Perrin

Henri Banvillet

Fr&eacute;d&eacute;ric Robert

A diaphragm-support disc for a polishing machine of the type in which a work piece to be polished is sandwiched between a radial front face of a diaphragm and a polishing surface or cloth. The diaphragm is extended across and wrapped around the peripheral edge of a radial front face of the disc, and a radial rear face of the diaphragm is subjected to pressure from a fluid. The diaphragm-support disc includes a main annular part that projects from the radial front face of the disc and is located in a peripheral region of the radial front face of the disc a predetermined distance from the peripheral edge of the radial front face of the disc. The main annular part can act on the work piece through the diaphragm so as to press the work piece onto the polishing surface or cloth by an axial displacement of the disc with respect to the polishing surface or cloth. In a preferred embodiment, a shorter secondary annular part projects from the radial front face of the disc on the peripheral edge of the radial front face of the disc some distance from the main annular part. A method of operating a polishing machine to polish a work piece is also provided.

Diaphragm-support disc for a polishing machine and method of operating a polishing machine

A process for polishing, on a polishing machine and under defined polishing conditions, the external surface of at least one wafer of integrated circuits comprising a projecting feature covered over the entire surface of the wafer with an external layer of a material, consisting in calculating a main equivalent thickness equal to the main surface density of the projecting feature multiplied by the thickness of the latter; in polishing, under the defined polishing conditions, a reference wafer comprising an external layer of the material, having a uniform thickness and covering the surface of this reference wafer, so as to determine the rate of removal by the polishing machine corresponding to the ratio of the thickness removed to the polishing time elapsed; in calculating a polishing time equal to the ratio of the aforementioned equivalent thickness to the aforementioned rate of removal; in calculating a total equivalent thickness equal to the sum of the main equivalent thickness and of a complementary thickness of preset value; in calculating a polishing time equal to the ratio of this total-equivalent thickness to the aforementioned rate of removal; and in carrying out, under the polishing conditions, the polishing operation on at least one wafer to be polished for a duration which is equal to the aforementioned polishing time or which depends on this time.

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Grenoble, France

Luc Liauzu