Copper Polishing Composition Using Guanidine Polymer to Prevent Depressions
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Solution Overview
Problem
Conventional polishing compositions for semiconductor devices fail to prevent the formation of unintended depressions beside wiring lines during chemical mechanical polishing, especially when the conductor layer is made of copper or copper alloys.
Innovation Solution
A polishing composition containing colloidal silica abrasive grains, a polishing accelerator, a water-soluble polymer with a guanidine structure, and an oxidant, which inhibits the formation of depressions by forming a protective film on the conductor layer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing compositions are used for copper conductor layers, then the polishing process can proceed, but unintended depressions form beside wiring lines due to corrosion at the boundary between conductor layer and insulator layer
Solution Approach 1:
The patent introduces a water-soluble polymer as an intermediary substance that selectively adsorbs to the insulator layer surface, creating a protective barrier between the polishing composition and the copper conductor layer at their boundary. This mediator prevents direct contact and corrosion at the vulnerable interface, eliminating depression formation while allowing polishing to proceed
Solution Approach 2:
The water-soluble polymer is applied in advance to the insulator layer surface before polishing begins. This preliminary action creates a protective film that prevents corrosion from occurring during the subsequent polishing process, countering the harmful effect before it can manifest as depressions
2Productivity
If polishing accelerators and oxidants are used to improve polishing efficiency, then the polishing rate increases, but corrosion at the conductor-insulator boundary worsens, leading to more depressions
Solution Approach 1:
The water-soluble polymer acts as a protective intermediary that allows the use of aggressive polishing accelerators and oxidants without their harmful effects. The polymer film permits efficient polishing while blocking corrosion at the conductor-insulator boundary, enabling high productivity without the usual trade-off of increased depression formation
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 composition effectively prevents the formation of depressions beside wiring lines, improving the flatness and surface quality of polished semiconductor devices.
Implementation Method 1
a water-soluble polymer including a constitutional unit originating from a polymerizable compound having a guanidine structure
Implementation Method 2
colloidal silica abrasive grains
Implementation Method 3
an oxidant
Data Source
AI summary
A polishing composition contains a polishing accelerator, a water-soluble polymer including a constitutional unit originating from a polymerizable compound having a guanidine structure such as dicyandiamide, and an oxidant. The water-soluble polymer may be a water-soluble polymer including a constitutional unit originating from dicyandiamide and a constitutional unit originating from formaldehyde, a diamine or a polyamine.