Polishing Composition Cobalt Dissolution Inhibitor CMP
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Solution Overview
Problem
The challenge in the damascene wiring technique is the easy dissolution of cobalt element-containing layers during chemical mechanical polishing (CMP), leading to pits or corrosion, which impairs the function of the cobalt layer.
Innovation Solution
A polishing composition with a pH of 4 or more and 12 or less, containing a cobalt dissolution inhibitor such as organic compounds with ether bonds, hydroxyl groups, carboxyl groups, and salts with molecular weights of 130 or more, is used to suppress the dissolution of cobalt during CMP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CMP is performed to remove excessive wiring material and barrier layer, then the metal film is planarized and wiring structure is formed, but the cobalt element-containing layer is dissolved causing pits or corrosion
Solution Approach 1:
The patent introduces a polishing composition as an intermediary medium between the CMP process and the cobalt layer. This composition contains specific inhibitors (phosphoric acid at 0.01-10 wt%, silane coupling agents, and surfactants) that mediate the interaction between the polishing pad and the cobalt layer, preventing direct harmful contact while allowing controlled material removal of other layers.
Solution Approach 2:
The patent modifies the chemical parameters of the polishing environment by controlling pH (maintaining alkaline or neutral conditions) and introducing specific chemical compounds (phosphoric acid, silane coupling agents, surfactants) to change the reactivity characteristics. These parameter changes make the polishing environment less corrosive to cobalt while maintaining effective polishing capability for other materials.
2Strength
If cobalt element-containing layer is used to compensate adhesiveness between barrier layer and copper, then adhesion is improved, but the cobalt layer becomes easily dissolved during polishing
Solution Approach 1:
The polishing composition acts as a protective intermediary during the polishing process. The phosphoric acid (0.01-10 wt%), silane coupling agents, and surfactants work together to create a protective chemical environment that prevents the polishing slurry from directly attacking the cobalt layer, thereby preserving the adhesion-enhancing cobalt layer while still allowing necessary material removal.
Solution Approach 2:
The patent creates a chemically inert polishing environment by using a polishing composition with controlled pH and specific inert additives. This inert environment prevents unwanted chemical reactions between the polishing slurry and the cobalt layer, protecting the cobalt from dissolution and corrosion while maintaining its adhesive function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution effectively prevents the dissolution and corrosion of cobalt element-containing layers, maintaining their functional integrity during the CMP process.
Implementation Method 1
a polishing composition having a high effect of suppressing the dissolution of a cobalt element-containing layer
Data Source
AI summary
The present invention relates to a polishing composition used in application in which a polishing object having a cobalt element-containing layer is polished, including: a cobalt dissolution inhibitor; and a pH adjusting agent, wherein the polishing composition has a pH of 4 or more and 12 or less, and the cobalt dissolution inhibitor is at least one member selected from the group consisting of an organic compound having an ether bond, an organic compound having a hydroxyl group, an organic compound having a carboxyl group and having a molecular weight of 130 or more, and salts thereof. According to the present invention, there is provided a polishing composition capable of suppressing the dissolution of a cobalt element-containing layer when a polishing object having a cobalt element-containing layer is polished.