Sequential Polishing Solutions for Semiconductor Substrate Flatness
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Solution Overview
Problem
Current polishing methods for semiconductor substrates, such as silicon wafers, face challenges in achieving high flatness and low defects while maintaining efficient polishing removal rates, as the incorporation of water-soluble polymers improves flatness and reduces defects but often prolongs the polishing time.
Innovation Solution
A method involving a stock polishing process with multiple sub-steps using different polishing solutions, where the content of water-soluble polymers and abrasive particle diameters are strategically varied to enhance surface flatness and reduce defects, including a first polishing solution with low polymer content and large abrasive diameter, a second solution with higher polymer content and intermediate abrasive diameter, and a third solution with even higher polymer content and smaller or no abrasive, applied sequentially to achieve efficient polishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If water-soluble polymer is incorporated into stock polishing composition to improve flatness and reduce surface defects, then manufacturing precision is improved, but productivity deteriorates due to prolonged polishing time
Solution Approach 1:
The stock polishing process is divided into multiple sub-steps, each using polishing compositions with different water-soluble polymer contents and abrasive particle sizes. This segmentation allows optimization of each sub-step for specific functions: removing defects while controlling flatness, thereby resolving the contradiction between manufacturing precision and productivity
Solution Approach 2:
The invention changes key parameters including water-soluble polymer content, abrasive particle size, and pH value across different polishing sub-steps. By systematically varying these parameters, the process achieves both high manufacturing precision (flatness and defect reduction) and maintained productivity (polishing removal rate)
2Reliability
If water-soluble polymer is incorporated into stock polishing composition to reduce surface defects, then reliability is improved, but loss of time increases due to prolonged polishing duration
Solution Approach 1:
The polishing process is segmented into multiple sub-steps with progressively increasing water-soluble polymer contents. This allows defect reduction to be achieved systematically without requiring excessive time in a single step, thereby improving reliability while minimizing time loss
Solution Approach 2:
Earlier sub-steps perform preliminary polishing with lower polymer contents to remove major defects, preparing the surface for subsequent sub-steps that focus on fine defect reduction. This preliminary action reduces the total time required for achieving high reliability
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
This approach allows for the realization of high flatness and low defects on semiconductor substrates with reduced polishing time, improving the efficiency of the polishing process by optimizing the use of water-soluble polymers and abrasive sizes in a sequential manner.
Implementation Method 1
a first stock polishing sub-step of preliminarily polishing the substrate; The plurality of stock polishing sub-steps include a first stock polishing sub-step that is performed by supplying a first polishing solution
Data Source
AI summary
A substrate polishing method includes a stock polishing step comprising a plurality of stock polishing sub-steps in which a first polishing solution, a second polishing solution, and a third polishing solution are applied, in that order, to a substrate. A content COMP1 of water-soluble polymer P1 in the first polishing solution, a content COMP2 of water-soluble polymer P2 in the second polishing solution, and a content COMP3 of water-soluble polymer P3 in the third polishing solution satisfy COMP1<COMP2<COMP3, and any one of the following conditions is satisfied: (1) average primary particle diameter DA3 of abrasive A3 in the third polishing solution is smaller than average primary particle diameter DA1 of abrasive A1 in the first polishing solution and average primary particle diameter DA2 of abrasive A2 in the second polishing solution; and (2) the third polishing solution does not contain abrasive A3.