Chemical mechanical polishing solution and application thereof

Abstract

The invention provides a chemical mechanical polishing solution, and further provides application of the chemical mechanical polishing solution in copper and silicon polishing. The chemical mechanicalpolishing solution comprises silicon dioxide grinding particles, a halogen-containing oxidant, a polishing rate accelerant and water, wherein the surfaces of the silicon dioxide grinding particles are grafted with an organic matter of which the molecular tail end is provided with a sulfonic acid group. The polishing solution disclosed has the advantages that (1) the polishing solution disclosed by the invention uses a halogen-containing oxidant and has a very high polishing rate on copper and silicon; (2) the polishing solution adopts silicon dioxide grinding particles with sulfonic acid groups at the molecular tail ends grafted on the surfaces, so that the stability of the polishing solution colloid is greatly improved; and (3) residues of the grinding particles on the surface of a waferare reduced in the polishing process, the polishing quality is improved, and the polishing defects are reduced, so that the yield of products is improved.

Description

technical field [0001] The invention relates to the field of chemical mechanical polishing, in particular to a chemical mechanical polishing liquid and its application in copper and silicon polishing. Background technique [0002] TSV technology (Through-Silicon-Via) is the latest technology to realize the interconnection between chips by making vertical conduction between chips and between wafers. Different from the previous IC package bonding and overlay technology using bumps, the advantage of TSV is that it can maximize the density of chips stacked in the three-dimensional direction, minimize the overall size, and shorten the interconnection, thereby increasing chip speed and reducing power consumption. The crystal back thinning technology in TSV technology requires chemical mechanical polishing. At this time, the polishing liquid used is required to have a very high polishing speed for both silicon and copper materials. [0003] Generally, higher silicon polishing spee...

AI Technical Summary

Problems solved by technology

However, if an oxidizing agent is added, such as hydrogen peroxide, the hydrogen peroxide will oxidize the surface of the elemental silicon into silicon dioxide, which is more difficult to remove

In addition, under alkaline conditions, oxidizing agents such as hydrogen peroxide are very unstable and will quickly decompose and fail.

[0017] In addition, the polishing liquid in the above-mentioned patent also has a problem: under high ionic strength, for example, adding a large amount of potassium ions (>0.1mol / Kg), the average particle size of the abrasive particles will gradually increase, resulting in unstable polishing liquid, very Easy to settle and stratify

However, such positively charged silicon dioxide abrasive particles are easy to combine with the negatively charged silicon wafer surface, and tend to remain on the surface of the silicon wafer, resulting in poor polishing effect and increased cleaning difficulty

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