Metal lug surface planarization method

Abstract

The invention relates to a metal lug surface smoothening method, including that: a wafer which is provided with a plurality of metal lugs on an active surface is provided, wherein every surface of metal lugs is rough; a planarization device which is provided with an upper pressure plate is provided; the wafer is conveyed and placed on the planarization device, so that a plurality of metal lugs of the active surface of the wafer face to the lower surface of the upper pressure plate; a pressure is applied to a plurality of metal lugs on the active surface of the wafer, namely the lower surface of the upper pressure plate is pressed down and is contacted with the rough surface of a plurality of metal lugs on the active surface of the wafer, so as to planarize the rough surface of a plurality of metal lugs on the active surface of the wafer; and the upper pressure plate is removed, namely the upper pressure plate is separated from a plurality of metal lugs on the active surface of the wafer. Thus, the surface of a plurality of metal lugs on the active surface of the wafer is planarized.

Description

technical field [0001] The present invention relates to a semiconductor structure, and more particularly to a method of eliminating surface roughness of a plurality of metal bumps on a wafer. Background technique [0002] In order to provide the flatness that the semiconductor needs to achieve after entering the sub-half micron (sub-half micron) through the process, IBM Corporation of the United States has successfully developed a method called chemical mechanical polishing (Chemical mechanical polishing, CMP) process. CMP is currently the only method known to provide comprehensive planarization of VLSI or ULSI processes. If the control parameters of the process are selected at the optimum value, CMP can provide the flatness of the grinding surface as high as 94%. [0003] With current bumping technology, it is always difficult to control the planarization and bump height uniformity of all metal bumps on a whole wafer or chip. The main reason is that it is difficult to co...

AI Technical Summary

Problems solved by technology

[0003] With today's bumping technology, it is always difficult to control the planarization and bump height uniformity of a whole wafer or all metal bumps on a chip

The main reason is that it is difficult to control the current density and the concentration of the electroplating solution during electroplating.

Also because of this, no matter in a single wafer or between two wafers or the height of metal bumps between chips can not be effectively controlled all the time

Due to the unevenness of the process when making metal bumps, the heights of multiple metal bumps on the wafer are inconsistent, and the difference in height will lead to a decrease in yield

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