Abstract: A process and etchant gas composition for anisotropically etching a trench in a silicon nitride layer of a multilayer structure. The etchant gas composition has an etchant gas including a polymerizing agent, a hydrogen source, an oxidant, and a noble gas diluent. The oxidant preferably includes a carbon-containing oxidant component and an oxidant-noble gas component. The fluorocarbon gas is selected from CF4, C2F6, and C3F8; the hydrogen source is selected from CHF3, CH2F2, CH3F, and H2; the oxidant is selected from CO, CO2, and O2; and the noble gas diluent is selected from He, Ar, and Ne. The constituents are added in amounts to achieve an etchant gas having a high nitride selectivity to silicon oxide and photoresist. A power source, such as an RF power source, is applied to the structure to control the directionality of the high density plasma formed by exciting the etchant gas.

Abstract: A process for removing a resist material containing a chlorine residue from an organic substrate. The process first removes the chlorine residue from the resist material by exposing the resist material to an abbreviated plasma which also removes a portion of the resist material. The remainder of the resist material is removed by exposing the resist material to a solvent which does not affect the organic substrate.

Abstract: A process for estimating a critical dimension of a trench formed by etching a substrate. First, a regression model is constructed for estimating the critical dimension, in which principal component loadings and principal component scores are also calculated. Next, a substrate is etched and spectral data of the etching are collected. A new principal component score is then calculated using the spectral data and the principal component loadings. Finally, the critical dimension of the trench is estimated by applying the new principal component score to the regression model.

Abstract: Decoupled plasma etching process used to make a protruding structure having vertical or near vertical sidewalls. The decoupled plasma etching process comprises the following steps:forming a mask on top of a semiconductor substrate defining the lateral size of the protruding structures to be formed in said substrate,feeding HCl, Cl.sub.2 and N.sub.2 into a plasma chamber to provide an ion plasma when applying source power,causing said ions to diffuse towards the substrate by applying a bias power such that the portions of said substrate not being covered by said mask are etched away, wherein the dosage of HCl, Cl.sub.2 and N.sub.2 is chosen such that newly formed portions of the sidewall surfaces are passivated by by-product of Si, Cl, and N.sub.2 and thus become protected from further being etched. The bias power is less than 70 Watts to ensure that the etching process is predominantly chemical.