CMP Slurry for Copper Interconnects Reducing Dishing and Defects
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Solution Overview
Problem
The existing CMP slurry compositions for polishing copper interconnects suffer from low polishing rate, high polishing defects, and dishing due to the reinforcement of the copper oxide layer, which leads to increased fabrication costs and reduced productivity in semiconductor manufacturing.
Innovation Solution
A CMP slurry composition comprising colloidal silica with specific surface areas, an oxidant, a complexing agent, a corrosion inhibitor, and a pH regulator, optimized in terms of weight percentages and types, is used to enhance the polishing rate while minimizing defects and dishing. The composition includes a combination of spherical and cocoon type colloidal silica, specific oxidants, and inhibitors like benzotriazole derivatives, with a pH range of 6 to 8 to prevent corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complexing agents or chelating agents are added to reinforce the copper oxide layer, then polishing defects and penetration of foreign substances are reduced, but polishing rate deteriorates and dishing occurs
Solution Approach 1:
The patent changes the chemical parameters of the slurry by adding specific additives (corrosion inhibitor, complexing agent, pH regulator) to control the copper oxide layer properties. The corrosion inhibitor prevents excessive oxidation, the complexing agent controls Cu ion solubility, and the pH regulator maintains optimal chemical environment, thereby achieving both high polishing rate and low dishing
Solution Approach 2:
The patent uses a composite approach by combining multiple polishing particles (colloidal silica with specific surface area 72.9-88.5 m2/g) with carefully selected chemical additives. This composite slurry formulation creates a balanced system where mechanical polishing and chemical etching work synergistically to achieve high rate and low dishing simultaneously
2Reliability
If complexing agents or chelating agents are added to reinforce the copper oxide layer, then foreign substance penetration is prevented, but polishing time increases causing erosion and dishing
Solution Approach 1:
The patent optimizes chemical parameters by adding corrosion inhibitor and pH regulator to control the copper oxide layer formation rate and properties. This allows the layer to form quickly with proper structure that prevents penetration, while maintaining high polishing rate to reduce overall polishing time
Solution Approach 2:
The complexing agent acts as an intermediary that controls the interaction between Cu ions and the copper oxide layer. It regulates ion solubility and layer structure formation, enabling the layer to provide protection against penetration while maintaining appropriate polishing rate to minimize time loss
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 optimized CMP slurry composition achieves a high polishing rate with reduced defects and dishing, thereby improving yield and productivity in semiconductor fabrication by effectively managing the copper oxide layer during the polishing process.
Implementation Method 1
an oxidant, wherein the colloidal silica has a specific surface area (BET) of 72.9 m2/g to 88.5 m2/g and is present in an amount of 0.1% by weight (wt %) to 2 wt %
Implementation Method 2
one or more complexing agents or chelating agents are generally added to a CMP slurry for polishing copper interconnects so as to allow chelation or complexation of Cu+ and Cu2+ ions in a copper oxide layer
Implementation Method 3
a corrosion inhibitor, wherein the colloidal silica has a specific surface area (BET) of 72.9 m2/g to 88.5 m2/g
Implementation Method 4
CMP slurry composition for polishing copper interconnects includes colloidal silica
Data Source
AI summary
The present invention relates to a CMP slurry composition for polishing a copper line, the CMP slurry composition comprising a colloidal silica, an oxidizing agent, a complexing agent, a corrosion inhibitor, a pH regulator, and ultrapure water. The colloidal silica has a specific surface area (BET) of 72.9 to 88.5 m2/g, and 0.1 to 2 wt % of the colloidal silica is included in the CMP slurry composition. The CMP slurry composition has an excellent copper line polishing rate, has a low number of defects and minimizes scratches after polishing, and can minimize dishing.