CMP Polishing Composition for Polysilicon Residue and Recess Suppression
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Solution Overview
Problem
Conventional polishing compositions fail to effectively reduce the remaining of polysilicon and suppress recesses during the polishing process, especially when silicon dioxide or silicon nitride is used as a stopper film.
Innovation Solution
A polishing composition comprising colloidal silica, an alkali metal salt, polyalkylene glycol, and a polymer compound X, with a pH of 9.0 to 11.5, is used to polish a second layer and expose a first layer, where the first layer has an oxygen-silicon or nitrogen-silicon bond, and the number of silanol groups in colloidal silica is controlled between 6/nm² and 22/nm² to enhance polishing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing composition is used to achieve high selectivity, then polishing removal rate ratio is improved, but remaining of polysilicon and recesses occur
Solution Approach 1:
The patent changes the chemical composition parameters of the polishing slurry by introducing specific organic compounds (polymer compounds with carboxyl groups, cellulose derivatives) and controlling pH (9.0-11.5), which modifies the polishing mechanism to reduce remaining and recesses while maintaining selectivity
Solution Approach 2:
The patent uses a composite polishing slurry containing colloidal silica particles combined with specific organic compounds (polymer compounds and cellulose derivatives), creating a multi-component system that achieves both high selectivity and reduced surface defects
2Manufacturing precision
If polishing composition aims to expose first layer by polishing second layer, then selectivity is improved, but remaining of second layer occurs
Solution Approach 1:
The patent optimizes pH parameters to 9.0-11.5 and controls the concentration of organic compounds to achieve balanced removal rates, allowing complete exposure of the first layer while minimizing remaining of the second layer
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 significantly reduces the remaining of polysilicon and suppresses recesses by promoting hydrogen bonding and surface protection, achieving improved polishing results.
Implementation Method 1
The composition significantly reduces the remaining of polysilicon and suppresses recesses by promoting hydrogen bonding and surface protection
Implementation Method 2
The composition significantly reduces the remaining of polysilicon and suppresses recesses by promoting hydrogen bonding and surface protection
Data Source
AI summary
An object of the present invention is to provide a new polishing composition that can reduce remaining of an object to be polished, which has to be polished, such as polysilicon, and suppress recesses. Provided is a polishing composition comprising colloidal silica; an alkali metal salt; polyalkylene glycol; at least one selected from the group consisting of a cellulose derivative and a polymer compound X; and water, the polishing composition having a pH of 9.0 to 11.5, the polymer compound X containing a repeating unit represented by the following formula (1):wherein A is a group selected from at least one kind of the followings:wherein m is an integer of 1 to 5; R1 to R4 are each independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms, wherein R1 and R2 may form a ring and, in a case where the ring is formed, at least one oxygen atom may be contained in the ring, and wherein R3 and R4 may form a ring and, in a case where the ring is formed, at least one oxygen atom may be contained in the ring; and at least one oxygen atom may be contained in a ring in the formula 1-1,the polymer compound X optionally further containing a repeating unit represented by the following formula (2):wherein A is a hydroxy group,(i) wherein the polishing composition is used in a step of polishing a second layer to expose a first layer in an object to be polished including the first layer provided with a recess portion and the second layer formed to fill the inside of the recess portion, and wherein the first layer is selected from the group consisting of a layer having an oxygen-silicon bond or a layer having a nitrogen-silicon bond, and the second layer has a silicon-silicon bond; and/or (ii) wherein the number of silanol groups in the colloidal silica is 6/nm2 or more and 22/nm2 or less.