Wafer Coating Nozzle Eccentric Liquid Supply
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Solution Overview
Problem
Bubbles in processing liquids can remain on substrates during semiconductor manufacturing, leading to non-uniform coating states due to inadequate removal methods.
Innovation Solution
A liquid processing method where the processing liquid is supplied to the substrate at an eccentric position and then moved towards the center while rotating at increasing speeds, utilizing centrifugal force to prevent bubble entrainment and ensure uniform coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If bubbles are removed from processing liquid using a bubble removing pipe, then bubbles can be removed from the processing liquid, but bubbles can still be entrained in the processing liquid when it reaches the substrate, resulting in non-uniform coating state
Solution Approach 1:
The substrate is pre-rotated at a first rotational speed before processing liquid supply begins, creating centrifugal force in advance. This preliminary rotation establishes the conditions for bubble removal before the liquid is applied, preventing bubble entrapment during coating
Solution Approach 2:
The substrate rotational speed is dynamically changed from a first rotational speed during liquid supply to a second rotational speed after supply completes. This dynamic adjustment optimizes both coating application and subsequent bubble removal, resolving the contradiction between uniform coating and bubble elimination
2Manufacturing precision
If the substrate is rotated at high speed to spread processing liquid, then coating uniformity is improved, but bubbles are more likely to be entrained in the processing liquid
Solution Approach 1:
The substrate is pre-rotated at a first rotational speed before processing liquid supply begins, creating centrifugal force in advance. This preliminary rotation establishes the conditions for bubble removal before the liquid is applied, preventing bubble entrapment during coating
Solution Approach 2:
The substrate rotational speed is dynamically changed from a first rotational speed during liquid supply to a second rotational speed after supply completes. This dynamic adjustment optimizes both coating application and subsequent bubble removal, resolving the contradiction between uniform coating and bubble elimination
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 prevents bubbles from remaining on the substrate, enhancing the uniformity of the coating state by ensuring the processing liquid spreads evenly over the substrate surface.
Implementation Method 1
the centrifugal force generated at the eccentric position is larger than the centrifugal force generated in the vicinity of the center of rotation of the substrate
Implementation Method 2
When the processing liquid spreads on the substrate rotating at the second rotational speed, the centrifugal force generated at the eccentric position is larger than the centrifugal force generated in the vicinity of the center of rotation of the substrate
Data Source
AI summary
There are provided a liquid processing method, a liquid processing apparatus and a recording medium for liquid processing which can enhance the uniformity of the coating state of a processing liquid on a substrate. A coating unit includes a rotary holder for rotating a wafer, a nozzle for supplying a processing liquid onto a surface of the wafer, and a controller for controlling the position of the nozzle with respect to the wafer. A liquid processing method includes: starting the supply of the processing liquid to the surface of the wafer at an eccentric position at a distance from the center of rotation of the wafer, and moving the position on the wafer to which the processing liquid is supplied toward the center of rotation of the wafer while rotating the wafer at a first rotational speed; and, after the processing liquid supply position has reached the center of rotation of the wafer, rotating the wafer at a second rotational speed which is higher than the first rotational speed, thereby allowing the processing liquid to spread toward the periphery of the wafer.