Method and apparatus for improving uniformity of large-area substrates

Abstract

Embodiments of the present invention generally provide methods and apparatus for improving the uniformity of a film deposited on a large-area substrate, particularly for films deposited in a PECVD system. In one embodiment, a plasma-processing chamber is configured to be asymmetrical relative to a substrate in order to compensate for plasma density non-uniformities in the chamber caused by unwanted magnetic fields. In another embodiment, a plasma-processing chamber is adapted to create a neutral current bypass path that reduces electric current flow through a magnetic field-generating feature in the chamber. In another embodiment, a method is provided for depositing a uniform film on a large-area substrate in a plasma-processing chamber. The chamber is made electrically symmetric during processing by creating a neutral current bypass path, wherein the neutral current bypass path substantially reduces neutral current flow through a magnetic field-generating feature in the chamber.

Description

Technical field [0001] The embodiments of the present invention are generally related to thin film deposition on large-area substrates. Background technique [0002] Liquid crystal displays or flat panels are commonly used for active matrix displays (such as computer and TV screens). Plasma-enhanced chemical vapor deposition (PECVD) is commonly used to deposit thin films on substrates, such as transparent substrates or semiconductor wafers used in flat panel displays. PECVD is usually accomplished by introducing a precursor gas or gas mixture into a vacuum chamber containing a substrate. The precursor gas or gas mixture is typically directed downwards through a spreading plate, where the spreading plate is adjacent to the top of the chamber. By applying radio frequency (RF) power to the chamber from one or more RF aids connected to the chamber, the precursor gas or gas mixture in the chamber is energized (eg, excited) into a plasma. The excited gas or gas mixture reacts to form a...

AI Technical Summary

Problems solved by technology

[0011] For substrates smaller than about 1300 mm x 1500 mm, the effect of slit valve opening on SiN film thickness uniformity and film property uniformity is virtually undetectable or cannot be avoided by optimizing process parameters to provide better uniformity

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