Bit Line Contact Void Cleaning to Prevent Semiconductor Particle Defects
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Solution Overview
Problem
As semiconductor devices become smaller and more complex, the influence of particle-induced defects during manufacturing becomes more significant, affecting manufacturing yield and device performance.
Innovation Solution
A method for manufacturing semiconductor structures that involves forming a first insulating layer, a conductive contact, a second insulating layer with an opening, a conductive line structure, a plasma oxide layer, a wet cleaning process using an aqueous solution with negatively charged ions, a capping layer, and an etching back process to remove the capping layer above the contact void.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plasma oxide layer is formed to cover exposed surfaces, then surface protection and insulation are improved, but positively charged ions are generated on the plasma oxide layer surface which can combine with negatively charged ions to form undesired crystals or particles
Solution Approach 1:
A wet cleaning process using an aqueous solution containing negatively charged ions is performed after plasma oxide layer formation to remove the positively charged ions before they can combine with negatively charged ions from subsequent etching processes to form particles. This preliminary removal action prevents the harmful effect before it occurs.
Solution Approach 2:
The negatively charged ions in the wet cleaning solution serve a dual purpose: they clean the plasma oxide layer surface and simultaneously neutralize/remove the positively charged ions that would otherwise be harmful. The harmful positively charged ions are converted into removable contaminants that can be easily cleaned away.
2Productivity
If device size is reduced to increase component density, then productivity and device functionality are improved, but the influence of particle-induced defects becomes more significant
Solution Approach 1:
The patent extracts and removes the harmful positively charged ions from the plasma oxide layer surface through a targeted wet cleaning process. By removing these ions before subsequent processing steps, the formation of particles that would cause defects is prevented, thereby protecting the miniaturized device structures from particle-induced defects.
Solution Approach 2:
The wet cleaning process is performed as a preliminary step before etching back the capping layer. This timing ensures that positively charged ions are removed before any subsequent processes that might generate negatively charged ions, preventing particle formation at critical stages of device fabrication where particle defects would be most harmful.
3Object-generated harmful factors
If a wet cleaning process using an aqueous solution with negatively charged ions is performed, then positively charged ions are removed preventing particle formation, but additional process steps are required
Solution Approach 1:
The aqueous cleaning solution performs multiple functions simultaneously: it cleans organic and inorganic contaminants from the plasma oxide layer surface and removes the harmful positively charged ions. This multi-functionality justifies the additional process step by achieving multiple cleaning objectives in a single operation.
Solution Approach 2:
The additional wet cleaning step is justified because it converts the harmful positively charged ions into removable contaminants and prevents the formation of particle defects that would require even more complex remediation processes. The simple aqueous cleaning solution provides a cost-effective and simple method to eliminate a complex particle formation problem.
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 effectively reduces particle-induced defects by removing positively charged ions from the plasma oxide layer, preventing the formation of undesired crystals or particles, and thereby enhancing device performance and increasing manufacturing yield.
Implementation Method 1
forming a plasma oxide layer to cover exposed surfaces of the conductive line structure, the second insulating layer, and the conductive contact
Implementation Method 2
performing a wet cleaning process by using an aqueous solution containing negatively charged ions
Implementation Method 3
performing an etching back process to remove the capping layer above the contact void
Data Source
AI summary
A method for manufacturing a semiconductor device includes: forming an isolation member defining an active region in a substrate; forming a first insulating layer having a bit line contact over the substrate; forming a second insulating layer having a bit line opening on the first insulating layer; forming a bit line structure in the bit line opening, the bit line structure being electrically connecting to the bit line contact, and a contact void being formed surrounding the bit line structure and exposing a portion of the bit line contact; conformally forming a nitride spacer layer over the bit line structure, the second insulating layer, and the conductive contact; conformally forming a plasma oxide layer over the nitride spacer layer; and performing a wet cleaning process by using an aqueous solution containing negatively charged ions.