CMP Slurry Composition for Cobalt Film Dishing Suppression
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Solution Overview
Problem
Current chemical mechanical polishing (CMP) methods for semiconductor manufacturing face challenges in reducing dishing and erosion when polishing cobalt-containing films, which affect the reliability and quality of the semiconductor products.
Innovation Solution
A polishing liquid comprising colloidal silica, specific organic acids, passivation film forming agents, anionic surfactants, hydrogen peroxide, potassium, and sodium, with controlled pH and ClogP value differences, is used to suppress dishing and erosion during CMP of cobalt-containing films, enhancing the reliability of semiconductor products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP methods are used for cobalt-containing films, then polishing can be performed, but dishing and erosion occur on the surface
Solution Approach 1:
The invention changes the chemical composition parameters of the polishing liquid by incorporating specific organic acids (polycarboxylic acid and polyphosphonic acid), passivation film forming agents, and controlling the pH ratio (8.0-10.5) and ClogP value difference (2.00-8.00) between surfactants and passivation agents. These parameter changes optimize the chemical interaction with cobalt films to reduce dishing and erosion while maintaining polishing effectiveness.
Solution Approach 2:
The invention uses a composite polishing liquid formulation combining multiple functional components: colloidal silica (abrasive), organic acids (chemical reaction agents), passivation film forming agents (protective layer creators), and surfactants (surface activity enhancers). This composite approach addresses both mechanical removal and chemical protection needs to suppress dishing and erosion.
2Object-affected harmful factors
If polishing liquid components are increased to suppress dishing, then dishing suppression improves, but formulation complexity increases
Solution Approach 1:
The invention makes individual components perform multiple functions. For example, the organic acids serve both as chemical reaction agents for cobalt and as pH buffers. The passivation film forming agents simultaneously protect against dishing and control the chemical mechanical polishing rate. This multi-functionality reduces the need for additional separate additives, simplifying the overall formulation while maintaining effective dishing suppression.
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 polishing liquid effectively reduces dishing and erosion on cobalt-containing films, leading to improved reliability and quality of semiconductor products by controlling the polishing process and preventing excessive wear.
Implementation Method 1
a polishing liquid used for chemical mechanical polishing of an object to be polished having a cobalt-containing film, the polishing liquid comprising: colloidal silica
Implementation Method 2
hydrogen peroxide
Implementation Method 3
one or more passivation film forming agents selected from the group consisting of a compound represented by General Formula (1) and a compound represented by General Formula (2)
Implementation Method 4
an anionic surfactant
Data Source
AI summary
The present invention provides a polishing liquid which reduces the occurrence of dishing and erosion on a surface to be polished of an object to be polished having a cobalt-containing film after polishing in a case where the polishing liquid is applied to CMP of the object to be polished, and makes it possible to manufacture a semiconductor product having excellent reliability. The present invention also provides a chemical mechanical polishing method using the polishing liquid. The polishing liquid of an embodiment of the present invention is a polishing liquid used for chemical mechanical polishing of an object to be polished having a cobalt-containing film, and includes a colloidal silica, an organic acid, a passivation film forming agent, an anionic surfactant; hydrogen peroxide; potassium; and sodium, in which a value of a difference obtained by subtracting the ClogP value of the passivation film forming agent from the ClogP value of the anionic surfactant is more than 2.00 and less than 8.00, a mass ratio of a content of potassium to a content of sodium is 1×106 to 1×109, and the pH is 8.0 to 10.5.