Remote Plasma Edge Film Removal for Semiconductor Wafers
Solution Overview
Problem
Existing methods for removing unwanted films from the edge regions of semiconductor wafers are inefficient, particularly for films like silicon carbide and organosilicon glass, as they do not etch appreciably in common wet solvents, and edge exclusion hardware may interfere with deposition uniformity or require handling of wet solvents.
Innovation Solution
The use of remotely generated plasma to selectively remove unwanted films from the edge regions of semiconductor wafers by directing activated plasma species, such as atomic oxygen, to the edge areas while suppressing their intrusion into the active circuit regions using purge gases and materials that promote recombination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet chemical etching is used to remove unwanted films from edge regions, then the removal process is simple, but it cannot effectively etch films like silicon carbide and organosilicon glass
Solution Approach 1:
The patent changes the chemical state of the etching agent from liquid (wet chemical etching) to plasma phase (reactive ion etching). This parameter change enables effective etching of silicon carbide and organosilicon glass films that are resistant to wet chemicals, while maintaining a relatively simple process implementation through plasma generation and delivery systems.
2Manufacturing precision
If edge exclusion hardware is used to prevent deposition on edge regions, then deposition uniformity is maintained, but it interferes with certain plasma deposition systems and requires complex hardware
Solution Approach 1:
Instead of using hardware to exclude edges from deposition (preventing film formation), the patent inverts the approach by using plasma treatment to selectively remove films from edges after deposition. This eliminates the need for complex edge exclusion hardware while maintaining deposition uniformity on the active circuit regions.
3Manufacturing precision
If plasma species are directed to edge regions for film removal, then selective removal is achieved, but intrusion into active circuit regions may occur causing damage
Solution Approach 1:
The patent applies local quality by creating spatially differentiated plasma treatment zones. The plasma species are directed specifically at edge regions through controlled delivery mechanisms, while the active circuit regions are protected by controlling plasma flow paths and using appropriate chamber geometries. This ensures selective removal of edge films without damaging the active circuit areas.
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 method effectively removes unwanted films from the edge regions without affecting the films in the active circuit areas, improving process integration and reducing defects by eliminating the need for shadow ring hardware and minimizing wafer uniformity issues.
Implementation Method 1
generating a plasma in a remote plasma generator
Implementation Method 2
generating activated plasma species in a remote plasma generator
Implementation Method 3
suppressing their intrusion into the active circuit regions using purge gases and materials that promote recombination
Implementation Method 4
In particular embodiments, atomic oxygen is used to remove ashable films from the edge of semiconductor wafers
Data Source
AI summary
The present invention provides methods and apparatuses for removing unwanted film from the edge area of substrate using remotely-generated plasmas. Activated plasma species are directed to the edge of the substrate to contact and remove the unwanted film, while intrusion of the activated species to areas above the active circuit region (where the film is desired) is suppressed. In certain embodiments, intrusion of the activated species is suppressed by the use of a purge gas and/or the use of materials that promote recombination of plasma species. In particular embodiments, atomic oxygen is used to remove ashable films from the edge of semiconductor wafers.