This concept primarily originates from the semiconductor manufacturing process. Initially, semiconductor substrate polishing relied on mechanical polishing methods, such as magnesium oxide and zirconium oxide polishing, but this resulted in extremely severe surface damage. Until the late 1960s, a new polishing technique-Chemical Mechanical Polishing (CMP)-replaced the older methods.
CMP technology combines the advantages of both chemical and mechanical polishing: pure chemical polishing offers a fast polishing rate, high surface finish, low damage, and good flatness, but suffers from poor surface flatness and parallelism, leading to poor surface uniformity after polishing; pure mechanical polishing provides good surface uniformity and high surface flatness, but suffers from poor surface finish and deep damage layers.
Chemical mechanical polishing can achieve a relatively flat surface while maintaining a high polishing rate, resulting in flatness two orders of magnitude higher than other methods, making it an effective method for achieving global planarization.