Spin Chuck Bevel Cleaning Nozzle for Resist Edge Removal
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Solution Overview
Problem
Existing methods for removing excess resist from semiconductor wafers at the peripheral edge are inefficient, requiring long processing times and often result in the resist re-adhering to the wafer, leading to reduced product yields and potential contamination.
Innovation Solution
A method involving the application of a cleaning liquid to the peripheral edge of the wafer before the resist dries, using a beveled portion-specific nozzle system that supplies the cleaning liquid from the back surface and rotates the wafer to prevent re-adhesion, combined with assistive nozzles for targeted cleaning and temperature-adjusted solvents for efficient removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cleaning liquid is supplied to remove resist from the peripheral edge after the resist has been applied and dried, then the resist can be removed, but a long period of time is required and the cleaning liquid may remain on the wafer
Solution Approach 1:
The cleaning liquid is supplied to the peripheral edge of the wafer before the resist completely dries, during the spin coating process itself. This preliminary cleaning action removes excess resist at the edge while the resist is still in a removable state, eliminating the need for separate post-drying cleaning steps and reducing total processing time
2Reliability
If the cleaning liquid runs round the wafer from back surface to front surface to remove resist, then resist can be removed, but the resist scatters and re-adheres to the wafer, resulting in reduced product yields
Solution Approach 1:
The cleaning liquid is applied locally and selectively to the peripheral edge region of the wafer where excess resist accumulates, rather than allowing it to run across the entire wafer surface. This localized application prevents the cleaning liquid from transporting resist across the wafer front surface where it would re-adhere, while still effectively removing edge bead
Solution Approach 2:
The cleaning liquid flow is directed to extract and remove excess resist specifically from the peripheral edge region, separating this cleaning function from general wafer surface cleaning. By targeting only the edge region where excess resist exists, the system removes harmful resist accumulation without causing resist to scatter and re-adhere to the main wafer area
3Productivity
If the EBR process is not performed to maximize wafer peripheral edge consumption, then product yields can be increased, but the arm holding the wafer may be contaminated by resist
Solution Approach 1:
The cleaning liquid flow extracts and removes excess resist from the peripheral edge region before the wafer is transferred by the holding arm. By removing the contaminant (excess resist) from the edge region in advance, the holding arm is protected from contamination during subsequent handling operations
Solution Approach 2:
The peripheral edge cleaning is performed as a preliminary action during the spin coating process itself, before the wafer is transferred to the holding arm. This preliminary removal of excess resist prevents contamination of the holding arm during subsequent handling, eliminating the need for separate cleaning operations
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 approach significantly reduces processing time, prevents resist re-adhesion, and enhances product yields by ensuring thorough cleaning without contaminating the wafer or leaving residues.
Implementation Method 1
the wafer, which is rotated to centrifugally apply a film of the resist on a surface thereof
Implementation Method 2
the step of causing a cleaning liquid to run round a wafer from a back surface to a front surface
Data Source
AI summary
A spin chuck rotatably holds a semiconductor wafer, while resist is dropped on a surface of the semiconductor wafer through a resist application nozzle and thus applied thereon, and before the resist applied on the wafer dries, a cleaning liquid is supplied through a bevel cleaning nozzle to a portion of the wafer located at a peripheral portion thereof in a vicinity of a beveled portion to remove the resist adhering to the beveled portion. Thereafter, a film of the resist that is formed on the surface of the wafer is dried.