Copper Dry Etching with Cl2 / Ar Plasma Chemistry

Abstract

Etch rates 5000 A min were obtained for Cu in electron cyclotron resonance C12/Ar discharges at a sample temperature of 200°C for ion-neutral ratios 0.02. The rates are a strong function of ion-neutral ratio, ion flux, and ion energy through the need to have CuCl desorption rate faster than the CuCl, generation rate in order to avoid formation of a chlorinated selvedge layer. Postetch, in situ El2 plasma cleaning removes most of the chlorine residues and allows creation of clean, anistropic Cu features.

GaN LEDs fabricated using SF 6 plasma RIE

“…Our method provides a number of advantages. First, the use of conventional RIE and less corrosive fluorine gas not only reduces the production cost but also lowers the risk of corrosion in the RIE chamber and corrosive gas hazards [18–20]. Second, the etching rate for our LED arrays with substrates varies from 2–25 nm/min, which is significantly higher than the RIE etching methods reported by other groups [27, 34, 40].…”

“…Other specialised plasma etching techniques have been reported, such as reactive ion beam etching and chemically assisted ion beam etching with Cl 2 and BCl 3 as reactive gasses [17]. Although ECR‐RIE, ICP‐RIE, and ion beam etching have a unique ability to control the ion flux and ion energy separately, these techniques usually involve corrosive chlorine, chlorine mixtures, and chlorine‐based halocarbons based plasmas [18, 19] that damage the vacuum system and requires expensive reactive chamber and specific filtration system [20] in contrast with less corrosive SF 6 , CH 4 , Ar, and H 2 based plasmas [19]. In addition, hydrogen diffusion in GaN during ECR‐RIE can create electrically neutral complexes with dopants [21].…”

“…Hydrogen‐containing gasses like CH 4 and HBr have also been used for RIE patterning of GaN [25, 26], by breaking the stable bonds of GaN using high energy ions. However, these approaches still suffer from the diffusion of hydrogen in the hydrogen gas plasmas, the requirement for expensive reaction chamber, and the special gas residue disposal system [20]. While Basak et al [27] reported the RIE of GaN using SF 6 with the etching rate of 5.4–15.4 nm/min in, no LED devices were implemented using such a process to demonstrate its viability.…”

24.4: A New Method for Cu Patterning

“…The etch CD bias and residue have been measured by using scanning electron microscopy (SEM, Hitachi S-4800). In order to make an analysis for Cu residue, it has been divided into five separate levels (1)(2)(3)(4)(5). Residue level 1 indicates no residue present in the sample and the number of level increases as the residue in the sample increases.…”

Fabrication of 3D air-core MEMS inductors for very-high-frequency power conversions

“…Because of the isotropic etching profile, the pitch between nearby turns is limited. To reduce the winding pitch, alternative methods are mould-based electroplating 19,20,43 and anisotropic plasma etching of Cu [44][45][46] .…”