Method for increasing grinding wafer flatness

Abstract

The invention provides a method for improving the planeness of a ground wafer; the method is applied on a grinding machine which comprises a grinding head and a grinding disc; the grinding head is used for adsorbing and fixing the wafer; the grinding disc is used with the grinding head and used for grinding the wafer, wherein, the motion range of the grinding head does not exceed the surface of the grinding disc; the brim of the bottom of the grinding head is provided with a fixing ring which is used for fixing the wafer and is contacted with the grinding disc completely. Compared with the prior art, the even grinding force exerted on the wafer can improve the planeness of the wafer surface in one grinding process and can improve the production efficiency and the yield of the wafer simultaneously.

Description

technical field [0001] The invention relates to a chemical mechanical polishing process, in particular to a method for improving the flatness of a polished wafer. Background technique [0002] At present, copper is used as the metal material of the interconnection structure in integrated circuits, and a dual damascene (Dual Damascene) process is usually used to realize the copper interconnection of the integrated circuit. Using the dual damascene process to manufacture integrated circuit copper interconnection, after filling the copper into the wire trench, chemical mechanical polishing (Chemical Mechanical Polish) will be used to planarize the copper layer, remove excess copper on the dielectric layer, and make the wafer surface fully Permanent planarization for subsequent thin film deposition. [0003] Before the wafer enters the chemical mechanical polishing process, it will be marked to distinguish the wafer. The marking of the wafer is usually set on the edge of the wa...

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Problems solved by technology

[0004] In the prior art, since the grinding head is in the grinding process, the coverage of the grinding head has exceeded the wafer surface, that is, a part of the coverage of the grinding head is not in contact with the grinding disc. When a part of the grinding head is not in contact with the grinding disc When the time is high, the force on the grinding head on the grinding disc will change, that is, the grinding force on the wafer will be uneven, which will affect the flatness of the wafer being ground. Uniformity leads to copper residue at the engraved mark, which causes the wafer to be scrapped due to unclear engraved marks

At present, in order to avoid this situation, it is usually necessary to re-grind the edge of the wafer. However, if the re-grinding operation is not careful, it will affect the flatness of the center of the wafer. In addition, the re-grinding will prolong the grinding time and increase the production cost.

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