Post-Etch Hole Coating to Extend Semiconductor Q-Time
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Solution Overview
Problem
The short Q-time following dry etching in semiconductor wafer manufacturing is exacerbated by gaseous by-products, particularly organic polymers, leading to moisture and oxygen penetration through cracks, causing defects and negatively impacting productivity and yield.
Innovation Solution
A method involving post-etch processing that includes exposing dry-etched holes to a gaseous mixture of fluorine-based compounds like CF4 and O2, followed by a nitrogen-based plasma, to coat the holes with a non-organic polymer, sealing cracks and removing residuals, thereby extending Q-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry etching is performed to form holes in semiconductor structures, then the holes are successfully formed, but gaseous by-products (organic polymers) remain that cause moisture and oxygen penetration through cracks, reducing Q-time
Solution Approach 1:
A sealing layer is deposited immediately after dry etching while the structure is still in the processing chamber, before the organic polymer residuals can cause moisture and oxygen penetration. This preliminary action prevents Q-time failures by addressing the contamination issue before it occurs.
Solution Approach 2:
A sealing layer composed of inorganic materials (such as silicon oxide, silicon nitride, or silicon oxynitride) is introduced as an intermediary barrier between the organic polymer residuals and the external environment. This sealing layer blocks moisture and oxygen from penetrating through cracks in the organic polymer, thereby extending Q-time.
2Productivity
If the Q-time is kept short to maintain productivity, then manufacturing speed increases, but defects occur due to moisture and oxygen penetration through cracks formed during dry etching
Solution Approach 1:
The sealing layer is deposited as a preliminary protective measure immediately after dry etching, preventing moisture and oxygen penetration before defects can occur. This allows the process to maintain short Q-time intervals while ensuring high yield by proactively preventing failures.
Solution Approach 2:
The sealing layer creates an inert protective environment around the dry-etched holes, isolating the sensitive semiconductor structures from reactive moisture and oxygen in the ambient environment. This inert barrier prevents chemical reactions that would cause defects, thereby maintaining high yield even with short Q-time processing intervals.
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 seals cracks and removes residuals, significantly increasing Q-time, enhancing productivity and yield by preventing moisture and oxygen ingress.
Implementation Method 1
exposing the dry-etched hole to a gaseous mixture, the gaseous mixture comprises a fluorine based chemical compound
Implementation Method 2
removing fluorine based chemical compound residuals to provide an additionally coated hole by exposing the first coated hole to a nitrogen based plasma
Data Source
AI summary
There is provided a method that includes (i) removing organic polymer residuals formed on a dry-etched hole that leads to a semiconductor structural element and coating the dry-etched hole with a non-organic polymer to provide a coated hole by exposing the dry-etched hole to a gaseous mixture, the gaseous mixture includes a fluorine based chemical compound, before the removing, the dry-etched hole was least partially coated with dry-etch residuals that comprise the organic polymer residuals; and (ii) coating the coated hole and removing fluorine based chemical compound residuals to provide an additionally coated hole by exposing the first coated hole to a nitrogen based plasma.