Nickel-Phosphorous Polishing via Chemical-Mechanical Composition
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Solution Overview
Problem
Conventional chemical-mechanical polishing methods are inadequate for achieving low surface roughness and high polishing rates on nickel-phosphorous memory or rigid disks, which are essential for improved storage capacity and miniaturization in computer equipment.
Innovation Solution
A chemical-mechanical polishing method using a composition comprising wet-process silica, an oxidizing agent for nickel-phosphorous, and an aminopolycarboxylic acid, with a pH of 1 to 5, to effectively abrade and polish nickel-phosphorous substrates, enhancing surface finish and removal rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If smaller abrasive particles are used in polishing compositions, then surface roughness is reduced, but polishing rate decreases
Solution Approach 1:
The invention changes the chemical parameters of the polishing composition by introducing an oxidizing agent and controlling pH (1-5), which transforms the mechanical abrasion process into a chemical-mechanical polishing process. This allows the use of smaller silica particles (0.01-10 micrometers) to achieve both low surface roughness and acceptable polishing rates through enhanced chemical reactivity.
Solution Approach 2:
The polishing composition is formulated as a composite system combining wet-process silica particles with specific oxidizing agents (such as hydrogen peroxide, peracetic acid, or peroxymonosulfonic acid) and aminopolycarboxylic acids. This composite approach creates synergistic effects where the chemical components work together to dissolve nickel-phosphorous while the mechanical action of silica particles removes the dissolved material, achieving both smooth surfaces and efficient polishing.
2Manufacturing precision
If conventional CMP methods are used, then manufacturing process is simple, but surface finish and polishing rate are insufficient for high-density storage
Solution Approach 1:
The invention modifies key parameters of conventional CMP by adjusting pH to the acidic range (1-5) and incorporating specific oxidizing agents. These parameter changes enable the polishing composition to chemically react with nickel-phosphorous, significantly improving surface finish and polishing rate despite the increased complexity of the composition formulation.
Solution Approach 2:
The invention replaces purely mechanical abrasion with a chemical-mechanical process where chemical oxidation and dissolution play a dominant role. The oxidizing agents chemically transform nickel-phosphorous into soluble compounds that are then mechanically removed, reducing reliance on high mechanical stress and enabling superior surface finish with controlled polishing rates.
3Manufacturing precision
If polishing time is increased to achieve desired surface finish, then surface roughness is reduced, but production time and costs increase
Solution Approach 1:
By replacing mechanical abrasion with chemical-mechanical polishing, the invention dramatically increases the polishing rate. The oxidizing agents rapidly dissolve nickel-phosphorous through chemical reactions, allowing desired surface roughness to be achieved in significantly shorter times compared to conventional mechanical polishing methods.
Solution Approach 2:
The use of strong oxidizing agents (hydrogen peroxide, peracetic acid, peroxymonosulfonic acid) accelerates the chemical reaction with nickel-phosphorous, enabling rapid material removal. This accelerated oxidation process reduces polishing time while maintaining control over surface roughness, directly addressing the trade-off between surface quality and production time.
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 method achieves reduced surface roughness and increased polishing rates, thereby improving the performance and efficiency of memory or rigid disk manufacturing while maintaining cost-effectiveness.
Implementation Method 1
an agent that oxidizes nickel-phosphorous
Implementation Method 2
moving the polishing composition relative to the substrate to abrade at least a portion of the nickel-phosphorous to polish the substrate
Data Source
AI summary
The invention is directed to a method of chemically-mechanically polishing a surface of a substrate, comprising contacting a surface of a substrate comprising nickel-phosphorous with a chemical-mechanical polishing composition comprising wet-process silica, an agent that oxidizes nickel-phosphorous, and an aminopolycarboxylic acid, wherein the polishing composition has a pH of about 1 to about 5, and abrading at least a portion of the nickel-phosphorous to polish the substrate.