Knife Edge Ring for Semiconductor Wafer Cleaning
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Solution Overview
Problem
During semiconductor manufacturing, developer and cleaning solutions often form droplets on the bottom surface of wafers, which are not fully discharged, leading to contamination and product loss due to vaporization during the baking process, affecting circuit patterning and wafer usability.
Innovation Solution
A knife edge ring with a multi-stage inclined portion and discharge holes is positioned near the wafer's bottom surface, utilizing vacuum suction to guide and discharge these droplets effectively, preventing them from forming large droplets that could vaporize and contaminate the wafer edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the wafer is rotated at constant speed during developing process, then the developer is supplied uniformly, but liquid droplets form on the bottom surface and are not fully discharged
Solution Approach 1:
The knife edge ring extracts and removes the harmful liquid droplets from the wafer bottom surface by positioning discharge holes at the periphery where droplets accumulate, separating the removal function from the main developing process
Solution Approach 2:
The knife edge ring acts as an intermediary component between the wafer and the vacuum source, using the inclined portion to guide droplets toward discharge holes and enabling effective removal without directly contacting the wafer
2Manufacturing precision
If cleaning solution is supplied to the bottom surface, then cleaning is improved, but remaining solution forms large droplets that vaporize during baking
Solution Approach 1:
The knife edge ring performs preliminary removal of cleaning solution droplets from the wafer bottom surface before the baking process, preventing the formation of large droplets that would otherwise vaporize and contaminate the wafer during baking
Solution Approach 2:
The system converts the harmful effect of liquid accumulation into a beneficial outcome by using the same centrifugal force that causes droplet formation to concentrate droplets at the periphery, where they can be efficiently removed by the knife edge ring's discharge mechanism
3Loss of substance
If the knife edge ring is positioned close to the wafer bottom surface, then droplet discharge is improved, but the structure becomes more complex
Solution Approach 1:
The knife edge ring is segmented with multiple discharge holes distributed around its periphery, allowing efficient droplet removal from different locations simultaneously while maintaining a relatively simple overall structure
Solution Approach 2:
The discharge holes are positioned in the vertical dimension close to the wafer bottom surface, enabling effective droplet removal without increasing the horizontal footprint or overall structural complexity of the knife edge ring
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 solution ensures complete discharge of developer and cleaning solution droplets, preventing contamination and reducing product losses by effectively removing residual liquids from the wafer edge, thus maintaining the integrity of the semiconductor wafer during processing.
Implementation Method 1
utilizing vacuum suction to guide and discharge these droplets effectively
Implementation Method 2
A multi-stage inclined portion is formed in the outer side wall of the body
Data Source
AI summary
A knife edge ring apparatus is provided for use during semiconductor manufacturing which includes a ring-shaped body having an inner side wall, an outer side wall and a top surface having a predetermined width. A multi-staged inclined portion is formed in the outer side wall and a plurality of discharge holes penetrate the body. Each of the discharge holes have an inlet associated therewith positioned at the inclined portion. The knife edge ring allows developer and cleaning solution to be discharged away from the wafer. A method of cleaning the bottom surface of a semiconductor wafer is also provided which employs the use of the knife edge ring. Developer is supplied onto the top surface of a wafer. Spraying solution is sprayed onto the bottom surface of the wafer. The knife edge ring guides the developer and the cleaning solution remaining on the bottom surface of the wafer's edge along an inclined portion formed at an outer side wall of the knife edge ring and causes the developer and the cleaning solution to flow into a plurality of discharge holes.