Although the terms “first,” “second,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

In this document, the term “coupled” may also be termed as “electrically coupled”, and the term “connected” may be termed as “electrically connected”. “Coupled” and “connected” may also be used to indicate that two or more elements cooperate or interact with each other.

Reference is made to FIG. 1. FIG. 1 is a top view illustrating a multi-chamber system 100, according to some embodiments of the present disclosure. The multi-chamber system 100 includes a factory interface 110, at least one load lock chamber 120, a buffer chamber 130, and several process chambers 140. For illustration in FIG. 1, the factory interface 110 is coupled to the at least one load lock chamber 120. The at least one load lock chamber 120 is coupled to the buffer chamber 130. The process chambers 140 are disposed around the buffer chamber 130.