CMP Slurry with Amphiphilic Surfactant for Low-k Dielectric Selectivity
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Solution Overview
Problem
Current CMP technologies face challenges in achieving high selectivity for silicon dioxide over low-k and ultra-low-k dielectric materials while maintaining the integrity of these materials and not affecting the removal rates of metal and barrier layers during the polishing process, especially for advanced semiconductor wafer processing requirements.
Innovation Solution
A novel aqueous polishing composition comprising silica or ceria abrasive particles and amphiphilic nonionic surfactants with specific hydrophobic and hydrophilic groups, which are used in a chemically mechanical polishing process to achieve high selectivity for silicon dioxide over low-k and ultra-low-k materials without impacting the removal rates of metal and barrier layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP slurries are used for polishing silicon dioxide layers, then the removal rate of silicon dioxide is achieved, but the selectivity over low-k and ultra-low-k materials deteriorates and their integrity is compromised
Solution Approach 1:
The invention changes the chemical composition parameters of the CMP slurry by incorporating specific organic additives (polyols, carboxylic acids, and their derivatives) that selectively interact with silicon dioxide while being inert to low-k and ultra-low-k materials. This parameter change enables high selectivity without damaging the sensitive dielectric materials.
Solution Approach 2:
The organic additives act as intermediary substances that mediate between the abrasive particles and the dielectric materials. These additives selectively adsorb onto silicon dioxide surfaces, facilitating controlled removal while preventing direct contact between abrasives and low-k/ultra-low-k materials, thus protecting their integrity.
2Manufacturing precision
If high selectivity for silicon dioxide is achieved over low-k and ultra-low-k materials, then the integrity of these materials is maintained, but the removal rate of metal and barrier layers may be affected
Solution Approach 1:
The invention applies local quality by creating different chemical environments for different materials on the substrate surface. The slurry composition is designed to provide selective chemical activity: organic additives interact with silicon dioxide to enable controlled removal, while metal and barrier layers experience different chemical conditions that maintain their removal rates. This spatially differentiated chemical interaction resolves the contradiction between selectivity and overall productivity.
3Productivity
If the CMP process achieves fast uniform removal of substrate material, then the desired planarity is achieved, but the risk of damaging low-k and ultra-low-k materials increases
Solution Approach 1:
The invention converts the potential harm of fast mechanical removal into benefit by introducing organic additives that create a protective chemical environment. The abrasives continue to provide fast uniform removal, but the organic additives selectively passivate low-k and ultra-low-k materials, preventing damage. Thus, the harmful mechanical action is converted into a beneficial process that achieves both speed and material protection.
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 solution effectively maintains the integrity of low-k and ultra-low-k materials by achieving high selectivity for silicon dioxide, thereby ensuring precise polishing and maintaining the integrity of these materials, while also not affecting the removal rates of metal and barrier layers, thus supporting advanced semiconductor processing.
Implementation Method 1
The MRR of silicon dioxide, in particular TEOS, can be suppressed by polyols which are selectively absorbed on the hydroxyl group rich surfaces
Implementation Method 2
The technique typically applies CMP compositions or slurries containing abrasives and other additives as an active chemistry between a rotating substrate surface and a polishing pad under an applied load
Implementation Method 3
The CMP process couples a physical process such as abrasion with a chemical process such as oxidation or chelation
Data Source
AI summary
An aqueous polishing composition comprising (A) abrasive particles and (B) an amphiphilic nonionic surfactant selected from the group consisting of water-soluble or water-dispersible surfactants having (b1) hydrophobic groups selected from the group consisting of branched alkyl groups having 10 to 18 carbon atoms; and (b2) hydrophilic groups selected from the group consisting of polyoxyalkylene groups comprising (b21 ) oxyethylene monomer units and (b22) substituted oxyalkylene monomer units wherein the substituents are selected from the group consisting of alkyl, cycloalkyl, or aryl, alkyl-cycloalkyl, alkyl-aryl, cycloalkyl-aryl and alkyl-cycloalkyl-aryl groups, the said polyoxyalkylene group containing the monomer units (b21 ) and (b22) in random, alternating, gradient and/or blocklike distribution; a CMP process for substrates having patterned or unpatterned low-k or ultra-low-k dielectric layers making use of the said aqueous polishing composition; and the use of the said aqueous polishing composition for manufacturing electrical, mechanical and optical devices.