Spin Coater Cup Aspiration System for Uniform Resist Film
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Solution Overview
Problem
The existing spin-coating apparatus for applying resist films on semiconductor wafers results in uneven film thickness due to the aspiration of mist, which introduces external air and requires powerful aspiration, contaminating measurement instruments and increasing costs.
Innovation Solution
An apparatus with a processing cup and aspiration system that separates the substrate's processing space from the exhaust space, using a small gap between the substrate and cup opening to minimize mist leakage and aspiration, and includes a sensor to measure airflow precisely, with an optional lid for sealed processing and atmosphere control to reduce solvent evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the exhaust port is located under the substrate to aspirate mist, then the mist can be exhausted, but the film thickness becomes uneven due to wind pressure affecting the substrate
Solution Approach 1:
The exhaust system is segmented into two separate ports: an aspiration port located at the bottom of the processing cup for aspirating external air, and an exhaust port located at the top for exhausting mist. This segmentation separates the air intake function from the mist exhaust function, eliminating the wind pressure effect on the substrate that caused uneven film thickness.
2Ease of operation
If the processing cup opening is large to allow substrate loading/unloading, then substrate access is easy, but mist leaks to above the substrate requiring powerful aspiration
Solution Approach 1:
A lid is introduced as an intermediary component that seals the processing cup opening during the coating process. This lid prevents mist from leaking above the substrate while still allowing substrate loading and unloading when opened, thereby reducing the aspiration power required to control mist.
3Object-generated harmful factors
If the exhaust port is positioned to exhaust all mist, then complete mist removal is achieved, but measurement instruments are contaminated by mist
Solution Approach 1:
The measurement function is extracted and positioned upstream in the exhaust flow path, before the mist is exhausted. The flow rate sensor measures the air flow rate at the aspiration port where mist concentration is low, separating the measurement location from the high-mist exhaust region and preventing instrument contamination.
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 configuration ensures a uniformly thick film, reduces mist leakage, decreases aspiration requirements, and allows precise measurement of exhaust airflow, maintaining instrument cleanliness and reducing maintenance costs.
Implementation Method 1
rotating the substrate to cause a force to disperse the liquid in a form of a film to form a film applied on an upper surface of the substrate
Implementation Method 2
an aspiration device aspirating the unnecessary atmosphere through the exhaust port
Data Source
AI summary
There is provided an apparatus including: a processing cup having an opening opened upward to allow a substrate to be loaded and unloaded, an exhaust port for exhausting an unnecessary atmosphere produced in forming a film applied on the substrate, and an aspiration port for aspirating external air; and an aspiration device aspirating the unnecessary atmosphere through the exhaust port, wherein when the substrate is accommodated in the opening of the processing cup, the substrate has a perimeter spaced from the opening by a predetermined gap, and below the substrate accommodated in the processing cup there is formed an exhaust flow path extending from the aspiration port to the exhaust port.