Substrate Rotation Alignment for Slit-Nozzle Coating Defects
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Solution Overview
Problem
Existing substrate processing methods using slit nozzles often result in abnormal film-thickness portions on substrates due to liquid pools formed outside valid areas, which can adversely affect subsequent processes.
Innovation Solution
A substrate processing apparatus and method that includes a substrate holder, a nozzle with a slit-like discharge port, and a system to acquire invalid area information on the substrate before processing, allowing for adjustment of the substrate's rotation position to ensure that any abnormal film-thickness portions are formed within the invalid area, thereby reducing processing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a slit nozzle is moved in the space above a substrate while discharging processing liquid, then the processing liquid can be applied to the substrate, but a liquid pool is generated on the substrate causing abnormal film thickness
Solution Approach 1:
The substrate rotation position is adjusted in advance before the coating process based on invalid area information. By preliminarily positioning the substrate so that the invalid area aligns with the discharge port projection, the harmful liquid pool is directed to the invalid area, preventing defects in the valid area.
2Loss of substance
If the opening width of the discharge port is adjusted to match the substrate dimension, then excess processing liquid is prevented from discharging outside the substrate, but liquid pool still forms on the substrate surface
Solution Approach 1:
The substrate is treated differently in different areas: the valid area requires precise film thickness control, while the invalid area can tolerate liquid pool formation. By rotating the substrate to align the invalid area with the discharge port projection, the liquid pool is localized to the invalid area, allowing the valid area to maintain uniform film thickness.
3Manufacturing precision
If a cutout portion is arranged at the terminal position of the slit nozzle, then the liquid pool is generated outside the valid area, but this solution is not always feasible depending on substrate shape and valid area distribution
Solution Approach 1:
Instead of using a fixed cutout portion on the substrate, the invention dynamically adjusts the substrate rotation position based on the specific substrate shape and invalid area location. The substrate rotator enables flexible repositioning for each substrate, making the solution adaptable to various substrate shapes and patterns.
4Reliability
If the substrate rotation position is adjusted based on invalid area information, then abnormal film-thickness portions are positioned within the invalid area, but additional measurement and control steps are required
Solution Approach 1:
The substrate itself provides the information needed for positioning through its invalid area features (such as notches or pattern characteristics). The imaging device captures the substrate pattern, and the rotation position is automatically determined based on this information, allowing the substrate to guide its own correct positioning without external intervention.
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 effectively reduces processing defects by predicting and positioning abnormal film-thickness portions within the invalid area, minimizing their impact on valid areas and improving the reliability of the substrate processing.
Implementation Method 1
a gap having a predetermined length is formed between the upper surface of the substrate held by the substrate holder and the nozzle, and with the gap filled with the processing liquid, the relative moving step includes relatively moving at least one of the substrate and the nozzle with respect to another one such that the processing liquid in the nozzle is drawn onto the upper surface of the substrate from the discharge port due to capillary action that occurs in the gap
Data Source
AI summary
An upper surface of a substrate that is carried into a substrate processing apparatus includes a valid area in which a circuit pattern is formed or to be formed and an invalid area. In a substrate rotator, an image of the substrate is picked up, so that the invalid area is identified. Based on invalid area information and information in regard to an abnormal film-thickness portion that is predicted in advance, a portion in which an abnormal film-thickness portion can be arranged in the invalid area is extracted. A rotation position of the substrate is adjusted such that an extracted portion in the invalid area is located in one end portion in a moving direction of a slit nozzle during a coating process. The substrate the rotation position of which is adjusted by the substrate rotator is transferred to a coating processor by a receiver-transferer.