Stud-Type Capacitors Using Carbon Support for DRAM Fabrication

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Solution Overview

Problem

Conventional silicon dioxide-based support materials for capacitor fabrication face challenges such as complex patterning due to dry etching, leading to tapered profiles and increased complexity in obtaining straight profiles, which limits the scalability of capacitors to thinner dimensions.

Innovation Solution

The use of carbon-containing support materials allows for improved patterning of stud-type capacitors, enabling the growth of storage node material within openings rather than deposition over the support material, thereby eliminating the need for etching and planarization steps, reducing process complexity and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If silicon dioxide support material is used for capacitor fabrication, then the support material provides structural stability, but the dry etching process becomes complex and produces tapered profiles instead of straight profiles

Engineering Contradiction:

Improveprofile straightnessVSAvoidpatterning complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the material parameter of the support material from silicon dioxide to carbon-containing material. This parameter change fundamentally alters the etching behavior, enabling straight profile formation through chemical etching rather than physical sputtering, thereby resolving the profile straightness and patterning complexity contradiction

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the mechanical sputtering-based dry etching process (used for silicon dioxide) with a chemical etching process that works effectively on carbon-containing materials. This substitution eliminates the lateral component issue and enables precise straight profile formation without the complexity associated with silicon dioxide etching

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If storage node material is deposited over silicon dioxide support material, then the support material can be removed, but additional etching and planarization steps are required increasing process complexity

Engineering Contradiction:

Improveprocess simplicityVSAvoidfabrication throughput

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent performs preliminary action by growing the storage node material directly within the openings of the carbon-containing support material rather than depositing it over the entire support material surface. This preliminary positioning eliminates the need for subsequent removal steps, reducing process complexity and improving fabrication throughput

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts the storage node material formation process from the conventional deposit-then-remove approach. By growing material only where needed (within openings) directly on the carbon-containing support material, the process eliminates unnecessary material deposition and removal steps, simplifying the manufacturing process

Inventive Principle:

Principle #2Taking out (Extraction)

3Volume of moving object

If capacitor dimensions are scaled to thinner dimensions, then the capacitor density increases, but the aspect ratio requirements become more stringent and harder to achieve with conventional processing

Engineering Contradiction:

Improvecapacitor footprintVSAvoidaspect ratio control

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent changes the support material parameter to carbon-containing material, which enables precise chemical etching. This allows for better control of opening dimensions and aspect ratios, making it feasible to scale capacitors to thinner dimensions while maintaining manufacturing precision

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes mechanical sputtering with chemical etching, which provides superior precision for defining narrow, high aspect ratio openings. This substitution is critical for scaling capacitors to thinner dimensions as chemical etching can achieve the required dimensional control and profile straightness that mechanical methods cannot

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 the formation of capacitors with higher aspect ratios and improved profile straightness, enhancing the scalability and efficiency of capacitor fabrication, particularly for DRAM arrays, by utilizing carbon-containing support materials that reduce feature charging and improve etching precision.

Implementation Method 1

utilizing carbon-containing support materials that reduce feature charging and improve etching precision

Methodology Applied

Scientific EffectFeature charging reduction:

Implementation Method 2

enabling the growth of storage node material within openings rather than deposition over the support material

Methodology Applied

Scientific EffectEpitaxial growth: Epitaxy

Data Source

PatentEP2313925B1Methods of making capacitors, dram arrays and electronic systems

Publication Date: 2017.10.25 MICRON TECHNOLOGY INC

AI summary

Some embodiments include methods of making stud-type capacitors utilizing carbon-containing support material. Openings may be formed through the carbon- containing support material to electrical nodes, and subsequently conductive material may be grown within the openings. The carbon-containing support material may then be removed, and the conductive material utilized as stud-type storage nodes of stud- type capacitors. The stud-type capacitors may be incorporated into DRAM, and the DRAM may be utilized in electronic systems.