Crown-Type Capacitor Bottom Electrode Spacer Formation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional methods for forming crown-type capacitors in semiconductor devices face issues with short-circuit failures due to inclining or collapsing bottom electrodes, and the formation of insulating spacers obstructs the deposition of capacitor insulation films.

Innovation Solution

A method involving the formation of insulating spacers only on the outer side of bottom electrodes, using a mask pattern and etch-back techniques to create a level difference, allowing for the deposition of capacitor insulation films without obstruction and enhancing mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the height of the cylindrical bottom electrodes is increased to increase the surface area and capacitance, then the capacitance is improved, but the bottom electrodes are liable to incline and collapse toward adjacent bottom electrodes causing short-circuit failure

Engineering Contradiction:

ImprovecapacitanceVSAvoidstructural stability of bottom electrodes

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

An insulating spacer is formed in advance around the bottom electrode before the electrode is etched back. This preliminary formation of the insulating spacer provides structural support that prevents the bottom electrode from inclining or collapsing during subsequent processing steps, enabling the electrode to maintain its vertical shape at greater heights while avoiding short-circuit failures between adjacent electrodes

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The insulating spacer acts as an intermediary structure between adjacent bottom electrodes. It provides mechanical support to the bottom electrode and maintains the spacing between electrodes, preventing direct contact and short-circuit failures while allowing the bottom electrode to achieve greater height for increased capacitance

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If insulating spacers are formed inside the cylindrical bottom electrodes to prevent short-circuit failure, then the reliability is improved, but the inner diameter of the opening is reduced causing obstacles against forming the capacitor insulator film

Engineering Contradiction:

Improveshort-circuit preventionVSAvoidcapacitor insulator film formation

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The insulating spacer is positioned only at the outer periphery of the bottom electrode rather than inside it. This local placement provides short-circuit prevention at the critical interface between adjacent electrodes while leaving the inner opening of the bottom electrode unobstructed, allowing capacitor insulator film to be deposited without difficulty

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of placing the insulating spacer in the radial direction inside the bottom electrode (which would block the opening), the insulating spacer is positioned in the vertical direction at the outer periphery. This dimensional change allows the spacer to provide structural support and prevent short-circuits without interfering with the capacitor insulator film formation process

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

Prevents short-circuit failures and enables the formation of capacitor insulation films without obstacles, while maintaining mechanical strength and ensuring effective capacitor construction.

Implementation Method 1

anisotropic-etching the first insulating film by using the mask pattern as an etching mask, to form a plurality of through-holes in the first insulating film

Methodology Applied

Scientific EffectAnisotropic etching:

Implementation Method 2

depositing a bottom electrode film on bottom and sidewall of the through-holes and on top of the mask pattern

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 3

depositing a second insulating film on the bottom electrode film to fill the through-holes

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 4

removing a top portion of the bottom electrode film and the second insulating film, to thereby separate the bottom electrode film into a plurality of bottom electrodes

Methodology Applied

Scientific EffectEtching:

Implementation Method 5

removing the mask pattern to form a level difference between the first insulating film and a top of the bottom electrodes

Methodology Applied

Scientific EffectEtching:

Implementation Method 6

depositing a third insulating film covering the first insulating film, the second insulating film and the bottom electrodes

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 7

etching-back the third insulating film to leave a plurality of insulating spacers on the respective bottom electrodes

Methodology Applied

Scientific EffectEtch-back:

Data Source

PatentUS7723202B2Method for manufacturing a semiconductor device including a crown-type capacitor

Publication Date: 2010.05.25 MICRON TECHNOLOGY INC

AI summary

A method for forming a semiconductor device includes a plurality of crown-type capacitors in a capacitor-receiving insulating film, wherein bottom electrodes of the capacitors have an insulating spacer between each two of the bottom electrodes. The insulating spacer is formed by removing a hard mask used as an etching mask for forming cylindrical holes receiving therein capacitors including the bottom electrodes.