In the processing of substrates such as semiconductor wafers and displays, a substrate is placed in a process chamber and exposed to an energized gas to deposit or etch material on the substrate. During such processing, process residues are generated and can deposit on internal surfaces in the chamber. For example, in sputter deposition processes, material sputtered from a target for deposition on a substrate also deposits on other component surfaces in the chamber, such as on deposition rings, shadow rings, wall liners, and focus rings. In subsequent process cycles, the deposited process residues can “flake off” of the chamber surfaces to fall upon and contaminate the substrate. To reduce the contamination of the substrates by process residues, the surfaces of components in the chamber can be textured. Process residues adhere to the textured surface and inhibit the process residues from falling off and contaminating the substrates in the chamber.
In one version, the textured component surface is formed by directing an electromagnetic energy beam onto a component surface to form depressions and protrusions to which process deposits adhere. An example of such a surface is a “Lavacoat™” surface, as described for example in U.S. patent application Ser. No. 10/099,307 to Popiolkowski et al, filed on Mar. 13, 2002 and published as U.S. Patent Application Publication No. 2003-0173526 on Sep. 18, 2003, and U.S. patent application Ser. No. 10/622,178 to Popiolkowski et al, filed on Jul. 17, 2003 and published as U.S. Patent Application Publication No. 2004-0056211 on Mar. 25, 2004, both commonly assigned to Applied Materials, Inc, and both of which are incorporated herein by reference in their entireties. However, a problem that can arise with such surfaces is that the process to create the surfaces can be prohibitively expensive, due to for example the requirements of the electromagnetic energy beam source, and can require a degree of accuracy in the scanning of the beam that can be difficult to achieve.
In another version, the textured component surfaces can comprise raised horizontal surfaces formed by providing a patterned photoresist mask on a surface and etching through the openings in the pattern, as described for example in U.S. Pat. No. 6,506,312 to Bottomfield, issued Jan. 14, 2003, which is herein incorporated by reference in its entirety. The raised horizontal surfaces formed by this method have inner angles that trap and secure loose process deposits. For example, the raised horizontal surfaces can comprise a star pattern that provides relatively sharp angles to accumulate process deposits. The horizontal raised surfaces can also have sharp angles at top corners formed between the top of the raised surfaces and the surface sidewalls. However, a problem with such textured surfaces is that a build-up of process residues can cause stresses in the angled surfaces, which can result in cracking and erosion of the textured surface, including cracking of the edges of the horizontal raised surfaces.
Accordingly, it is desirable to have a component comprising a textured surface that provides reliable processing results substantially without contaminating substrates. It is further desirable to have a method of fabricating a component having a textured surface that is substantially repeatable to provide consistent processing results. It is also desirable to have a component having a textured surface that is resistant to erosion and stresses caused by deposited process residues, and a method of fabricating such a component.