Polymer Planarization via Thermal Softening and Pressing
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Solution Overview
Problem
Current methods for planarizing polymer layers over non-uniform surfaces in semiconductor manufacturing are either expensive, time-consuming, or ineffective, particularly affecting the lithography process due to non-flat and non-uniform polymer surfaces.
Innovation Solution
A method and apparatus that involves softening a polymer layer using a heat source and pressing it against a flat, non-adhesive surface to conform to the surface, followed by separation, which can be performed in a vacuum environment to achieve a flat and uniform polymer layer without material consumption or surface defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CMP is used to planarize polymer layers, then planarization can be achieved, but the process becomes expensive and time-consuming
Solution Approach 1:
The patent replaces the mechanical CMP process with a thermal field-based approach. A heating element applies localized heat to the polymer layer, causing controlled softening and flow to achieve planarization without mechanical contact or polishing compounds, thereby eliminating the time-consuming mechanical removal process.
Solution Approach 2:
The patent changes the physical state parameter of the polymer layer by controlling temperature. By heating the polymer above its glass transition temperature, the material transitions from a rigid state to a soft, flowable state, enabling planarization through thermal softening rather than mechanical removal.
2Manufacturing precision
If CMP is used to planarize polymer layers, then planarization can be achieved, but the process becomes expensive due to polishing compound consumption
Solution Approach 1:
The patent eliminates the need for polishing compounds by replacing the mechanical CMP system with a thermal field-based softening approach. The heating element directly softens the polymer material, allowing planarization without any consumable polishing compounds or slurry materials.
Solution Approach 2:
The patent replaces expensive consumable polishing compounds with a reusable heating element. The thermal field source can be used repeatedly without degradation or consumption, eliminating ongoing material costs associated with CMP polishing compounds.
3Productivity
If spin-coating is used on non-flat substrates, then polymer coating can be applied, but the surface becomes non-uniform
Solution Approach 1:
The patent applies planarization treatment before the spin-coating process. By pre-heating and softening the polymer layer immediately after coating, the material flows to fill in surface irregularities and conform to the substrate topology, ensuring uniform thickness even on non-flat substrates.
Solution Approach 2:
The patent uses temperature parameter control to change the viscosity and flow characteristics of the polymer coating. By heating the coated layer above its glass transition temperature, the polymer becomes more fluid and can redistribute itself to achieve uniform thickness across the substrate surface.
4Manufacturing precision
If double coating and etch back is used to planarize photoresist, then planarization can be achieved, but the process becomes time-consuming and costly
Solution Approach 1:
The patent extracts and eliminates the unnecessary double coating and etch back steps from the photoresist planarization process. By applying thermal softening directly to the single photoresist layer, the method achieves planarization without requiring additional coating cycles or chemical etching operations.
Solution Approach 2:
The patent replaces the chemical etching process with a thermal field-based softening approach. Instead of using chemicals to remove material, the heating element softens the photoresist, allowing planarization through controlled flow and redistribution of the material.
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 provides a simple, cost-effective, and defect-free planarization of polymer layers, improving the lithography process by ensuring a uniform surface across both isolated and pattern-dense areas, and is universally applicable to various polymer materials.
Implementation Method 1
The polymer layer is heated to a glass transition temperature of the polymer material or to a temperature range within 90% of the glass transition temperature
Implementation Method 2
The contacting of the flat surface and the polymer layer is performed in a vacuum environment to prevent air from being trapped between the flat surface structure and the polymer layer
Data Source
AI summary
A processing chamber is disclosed for planarizing material layers (for example, polymer layers). An exemplary processing chamber includes a substrate table configured to support a substrate having a material layer formed thereover and a flattening structure having a substantially flat surface. The flattening structure moves freely with respect to a non-uniform surface of the material layer, such that the non-uniform surface is flattened as the substantially flat surface contacts the non-uniform surface. In some implementations, the processing chamber further includes a pressing mechanism operatively coupled to the flattening structure, and a pivotal interface coupling the flattening structure to the pressing mechanism. The pressing mechanism presses the substantially flat surface of the flattening structure to the non-uniform surface of the material layer, and the pivotal interface allows the flattening structure to pivot with respect to the pressing mechanism and with respect to the substrate.