Polysiloxane Coating Planarization for Stepped Substrates
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Solution Overview
Problem
Conventional methods for forming patterns on semiconductor substrates using polysiloxane compositions struggle with achieving flatness, especially on substrates with stepped surfaces and dense patterns, resulting in increased iso-dense bias and difficulty in obtaining high aspect ratio reverse patterns.
Innovation Solution
A method involving a double application process of polysiloxane compositions, where a first polysiloxane coating is applied and baked, followed by a second polysiloxane coating with a silanol group content of 30 mol % or less, to form a film with an iso-dense bias of 50 nm or less, allowing for effective planarization and high etching resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional polysiloxane composition is applied to a stepped substrate with dense resist patterns, then the substrate can be coated, but the coating film exhibits poor flatness and high iso-dense bias
Solution Approach 1:
The coating process is divided into multiple sequential coating steps, where each coating applies a thinner layer that collectively achieves the desired total thickness with superior flatness. This segmentation allows better control over film formation on stepped substrates with dense patterns, reducing iso-dense bias compared to a single thick coating application.
2Reliability
If the polysiloxane composition contains high silanol group content, then etching resistance is improved, but planarization capability deteriorates
Solution Approach 1:
The silanol group content in the polysiloxane composition is precisely controlled within the range of 20-40 mol%, optimizing the balance between etching resistance and planarization capability. This parameter optimization ensures that the coating film maintains sufficient etching resistance while achieving the required flatness on stepped substrates.
Solution Approach 2:
The invention uses a composite polysiloxane composition containing multiple components including silane-modified polymers, crosslinking agents, and catalysts. This composite formulation achieves both high etching resistance and excellent planarization by combining materials with complementary properties, where the crosslinking network provides etching resistance while the composition structure enables smooth film formation.
3Quantity of substance
If a single thick coating is applied to achieve sufficient film thickness, then coverage is improved, but film flatness and aspect ratio control worsen
Solution Approach 1:
The total coating thickness is achieved through multiple sequential coating applications rather than a single thick coating. Each coating applies a thinner layer that cures to form a uniform film, and subsequent coatings build upon this foundation. This segmented approach maintains better aspect ratio control and film flatness while achieving the required total thickness for adequate coverage.
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 enables the formation of a flat, high-aspect-ratio reverse pattern on semiconductor substrates with improved planarization and etching resistance, effectively addressing the limitations of conventional techniques.
Implementation Method 1
a first coating polysiloxane composition comprising a first coating polysiloxane which is a hydrolysate condensation product of a hydrolyzable silane raw material
Implementation Method 2
a first coating polysiloxane composition comprising a first coating polysiloxane which is a hydrolysate condensation product of a hydrolyzable silane raw material
Implementation Method 3
applying a first coating polysiloxane composition comprising a first coating polysiloxane onto a stepped substrate
Data Source
AI summary
A method for flatly covering a semiconductor substrate using a silicon-containing composition. A method for producing a polysiloxane-coated substrate, including a first step for forming a first polysiloxane coating film by applying a first polysiloxane composition for coating to a stepped substrate and firing the composition thereon and a second step for forming a second film by applying a second polysiloxane composition for coating to the first film and firing the composition thereon. The second film has an Iso-dense bias of 50 nm or less; the first polysiloxane contains a hydrolysis-condensation product of a hydrolyzable silane starting material containing a first hydrolyzable silane having four hydrolyzable groups in each molecule at a ratio of 0-100% by mole in all the silanes; and the second polysiloxane contains silanol groups at a ratio of 30% by mole or less relative to Si atoms, while having a weight average molecular weight of 1,000-50,000.