Fill Material Recessing by Solubility-Shifted Wet Development

Solution Overview

Problem

Current processes for recessing fill materials within patterned substrates, particularly in semiconductor processing, face challenges with throughput, variability, and cost due to increasing geometries and aspect ratios, requiring nanometer-level precision.

Innovation Solution

The method involves selective deposition of a grafting material with a solubility-shifting agent within openings on a multilayer stack, followed by activation to alter the solubility of the fill material, allowing for precise recessing through a wet development process using alternating solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If timed etch processes are used to control fill recess, then manufacturing precision may be maintained, but productivity decreases and variability increases

Engineering Contradiction:

Improvefill recess control precisionVSAvoidprocess throughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical/timed etch process with a chemical dissolution process. Instead of using etch chemistry with timed duration to control recess depth, the invention uses solubility differences of the fill material to achieve recess through selective dissolution, eliminating the need for precise timing control and improving both precision and throughput

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the controlling parameter from time (in timed etch processes) to solubility characteristics of the fill material. By selecting fill materials with different solubilities or by controlling dissolution conditions, the recess depth is determined by material properties rather than process timing, thereby improving precision and reducing variability

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If timed etch processes are used to control fill recess, then manufacturing precision may be maintained, but process variability increases

Engineering Contradiction:

Improvefill recess control precisionVSAvoidprocess variability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical/timed etch process with a chemical dissolution process. Instead of using etch chemistry with timed duration to control recess depth, the invention uses solubility differences of the fill material to achieve recess through selective dissolution, eliminating the need for precise timing control and improving both precision and throughput

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The fill material's solubility characteristics inherently control the recess depth without requiring external timing control. The material self-regulates the dissolution process based on its own solubility properties, reducing process variability and improving reliability

Inventive Principle:

Principle #25Self-service

3Ease of manufacture

If conventional recessing processes are used, then existing process flows are maintained, but nanometer-level precision is difficult to achieve

Engineering Contradiction:

Improveprocess simplicityVSAvoidfill recess precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the controlling parameter from time (in timed etch processes) to solubility characteristics of the fill material. By selecting fill materials with different solubilities or by controlling dissolution conditions, the recess depth is determined by material properties rather than process timing, thereby improving precision and reducing variability

Inventive Principle:

Principle #35Parameter changes

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 enables improved control and precision in recessing fill materials within narrow and high aspect ratio openings, enhancing process efficiency and reducing costs by achieving self-aligned recesses with high dissolution contrast.

Implementation Method 1

causing the solubility-shifting agent to diffuse into a portion of the fill material surrounding the grafting material

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

diffusion of the solubility-shifting agent causes the portion of the fill material to become insoluble to a predetermined solvent

Methodology Applied

Scientific EffectSolubility change: Solvation

Data Source

PatentUS11848236B2Method for recessing a fill material within openings formed on a patterned substrate

Publication Date: 2023.12.19 TOKYO ELECTRON LTD

AI summary

Process flows and methods are provided for recessing a fill material within openings formed within a patterned substrate. The openings are formed within a multilayer stack comprising a target material layer and one or more additional material layers, which overly and differ from the target material layer. After the openings are formed within the multilayer stack, a grafting material comprising a solubility-shifting agent is selectively deposited within the openings, such that the grafting material adheres to the target material layer without adhering to the additional material layer(s) overlying the target material layer. Next, a fill material is deposited within the openings and the solubility-shifting agent is activated to change the solubility of a portion of the fill material adjacent to and surrounding the grafting material. Then, a wet development process is used to remove the soluble/insoluble portions of fill material to the recess the fill material within the openings.