Developer Nozzle Pillar Shearing for CD Uniformity
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Solution Overview
Problem
In semiconductor device manufacturing, the uniformity of the critical dimension (CD) of resist patterns is compromised due to developer droplets adhering to the substrate during the development process, leading to defects and variations in the development process.
Innovation Solution
A developing method and apparatus that utilize a developer nozzle to form a liquid collection portion on a semiconductor substrate, which is then lifted using surface tension to create a pillar with an upwardly-tapered end, and a shearing force is applied to separate the developer from the nozzle, preventing droplet adherence and ensuring uniform development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the developer nozzle is lifted after spreading the liquid collection portion, then the developer can be removed from the substrate, but developer droplets may adhere to the opposing surface and drop onto the substrate causing defects
Solution Approach 1:
The patent applies preliminary anti-action by forming a pillar shape with an upwardly-tapered upper end before droplet formation occurs. The opposing surface is disposed at a position where it does not interfere with the pillar formation, preventing the harmful effect of droplet adhesion before it can happen. This resolves the contradiction by anticipating and preventing the defect while maintaining efficient developer removal.
Solution Approach 2:
The patent implements preliminary action by controlling the lifting process to form a specific pillar shape with tapered upper end before the developer can form droplets that would adhere to the opposing surface. The opposing surface is positioned in advance to allow this pillar formation to occur without interference, ensuring clean developer removal without defects.
2Manufacturing precision
If the opposing surface is positioned close to the substrate to form a liquid collection portion, then developer concentration uniformity is improved, but the opposing surface may come into contact with developer droplets
Solution Approach 1:
The patent applies preliminary anti-action by positioning the opposing surface at a specific distance from the substrate that allows liquid collection portion formation with good concentration uniformity, while simultaneously preventing the opposing surface from interfering with pillar formation and droplet adhesion. This optimal positioning resolves the contradiction by preventing harmful droplet contact while maintaining the benefits of close positioning for uniformity.
Solution Approach 2:
The patent applies local quality by creating a pillar shape with an upwardly-tapered upper end, where the local geometry of the developer liquid changes from a flat liquid collection portion to a tapered pillar structure. This local structural change ensures that the developer is contained in a controlled shape that prevents droplet formation and adhesion to the opposing surface, while maintaining good concentration uniformity in the liquid collection portion.
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 technique enhances the uniformity of the CD by preventing developer droplets from adhering to the nozzle and dropping onto the substrate, thereby reducing defects and maintaining pattern resolution.
Implementation Method 1
lifting a portion of the liquid collection portion below the discharge port by a surface tension of the developer
Implementation Method 2
the developer flows due to the movement of the developer nozzle which is in contact with the liquid collection portion and the rotation of the wafer. As such, the developer spreads while being stirred.
Data Source
AI summary
A developing method includes: horizontally holding a substrate; disposing an opposing surface of a developer nozzle that faces a portion of a surface of the substrate, above one of central and peripheral portions of the surface; discharging a developer to form a liquid collection portion of the developer; spreading the liquid collection portion by moving the developer nozzle toward the other of the central and peripheral portions with the opposing surface brought into contact with the liquid collection portion; lifting the developer nozzle relative to the surface while stopping the discharge of the developer, and pulling up a portion of the liquid collection portion; stopping the lifting, and forming a pillar of the developer having a tapered upper end which is brought into contact with the opposing surface; and applying a shearing force to the pillar to shear the tapered upper end and separating the pillar from the opposing surface.