Semiconductor fabricating system having hybrid brush assembly

A method, comprising:

• forming a photoresist layer on a front surface of a wafer;
• holding the wafer via a wafer stage;
• after forming the photoresist layer, moving a brush assembly toward the wafer to contact a backside surface of the wafer while the wafer stage holds the wafer from the front surface of the wafer such that the backside surface of the wafer faces the brush assembly, wherein the brush assembly comprises an inner brush member and an outer brush member laterally surrounding the inner brush member, and wherein from a cross-sectional view, the outer brush member has a first level top surface, a vertical inner surface, and a beveled inner surface connecting the first level top surface and the vertical inner surface, and the inner brush member has a second level top surface in a position lower than a topmost position of the beveled inner surface and higher than a lowermost position of the beveled inner surface;
• rotating the brush assembly relative to the wafer to polish the backside surface of the wafer;
• and
• after moving the brush assembly and rotating the brush assembly, exposing the photoresist layer on the front surface of the wafer.

A method, comprising:

• holding a wafer via a wafer stage;
• performing a first backside cleaning operation by initiating a relative motion between a first brush assembly and the wafer stage while the wafer stage holds the wafer from a front surface of the wafer such that a backside surface of the wafer faces the first brush assembly, and wherein the first brush assembly is moveably located below the wafer stage, and the first brush assembly comprises:
• a plurality of inner protruding portions arranged around a rotation axis;
• and
• a plurality of outer producing portions arranged around the rotation axis and surrounding the inner protruding portions, wherein a distance between two adjacent outer protruding portions is greater than a distance between two adjacent inner protruding portions, wherein in a cross-sectional view, the outer protruding portions each have a level top surface, a vertical inner surface, and a beveled inner surface connecting the level top surface and the vertical inner surface, and the beveled inner surface has a greater horizontal dimension than the level top surface, and wherein the inner protruding portions are composed of a first material having a greater rigidity than a second material composing the outer protruding portions;
• rotating the first brush assembly relative to the wafer during the first backside cleaning operation;
• and
• after performing the first backside cleaning operation, performing a second backside cleaning operation using a second brush assembly comprising a single-material cylindrical brush.