Electropolishing liquid and process for planarization of metal layer

A technology of electrolytic polishing and metal layer, which is applied in the manufacture of circuits, electrical components, semiconductor/solid-state devices, etc.

Inactive Publication Date: 2007-04-25
BASF CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the deposited copper layer forms a height difference due to the grooves on the wafer surface, and this height difference further affects the planarization effect of the subsequent electrolytic polishing process

Method used

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  • Electropolishing liquid and process for planarization of metal layer
  • Electropolishing liquid and process for planarization of metal layer
  • Electropolishing liquid and process for planarization of metal layer

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Embodiment Construction

[0014] FIG. 1 is a cross-sectional view of a wafer 10 . As shown in FIG. 1 , the wafer 10 includes a substrate 12 , a dielectric layer 14 , a barrier layer 16 and a metal layer 20 . The metal layer 20 can be a copper layer and has a protrusion 22 and a recess 24 . The present invention uses an electrolytic polishing solution to planarize the metal layer 20 . The electrolytic polishing solution includes an alcohol-based additive and an acid solution. Preferably, the alcohol-containing additive can be glycerin, methanol or ethanol, and the acid solution contains phosphoric acid and an organic acid additive. Furthermore, the acid solution may also contain sulfuric acid. The preparation method of the electrolytic polishing liquid is to mix a predetermined ratio of phosphoric acid and an alcohol-based additive, and then add the organic acid additive. The organic acid additive can be acetic acid or citric acid, wherein the concentration of acetic acid is between 10000-12000 ppm,...

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Abstract

The invention reveals an electrolytic polishing fluid containing alcohol-based additives and its smoothened metal layer method. The said electrolytic polishing fluid contains an alcohol-based additives and acid solution. Optimization, the said alcohol-based additives can be glycerol, methanol or ethanol, the said acid solution contains phosphoric acid and organic acid additives, the organic acid additives can be acetic acid or citric acid. The invention degrades the burnishing rate of the said metal layer surface through the said alcohol-based additives forming the diffusion restraint layer on the said metal layer surface, but the rabbet and prominence of the said metal layer show the same degree of polishing inhibition in some certain concentration. Adding organic acid additive in the electrolytic polishing liquid leads to the difference of organic acid concentration of the convex and concave metal layer thereby causes greater difference of polishing rate of the convex and concave.

Description

technical field [0001] The invention relates to an electrolytic polishing liquid and its method for flattening a metal layer, in particular to an electrolytic polishing liquid containing an alcohol-based additive and its method for flattening a metal layer. Background technique [0002] In semiconductor manufacturing technology, high-density photolithography process requires a flat surface without height difference to avoid exposure scattering, so as to realize pattern transfer of precise conductive lines. Chemical mechanical polishing technology is the most widely used surface planarization technology in semiconductor manufacturing process. However, the chemical mechanical polishing technology faces important issues such as pattern effect, removal selectivity ratio, metal wire sinking phenomenon, scratches, insulation wear and post-polishing cleaning in practical application. Furthermore, for the low stress requirements of 12-inch wafers and low dielectric constant materia...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25F3/22H01L21/3063H01L21/465
Inventor 谢嘉民刘书宏戴宝通
Owner BASF CORP
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