Tokyo Electron Limited

Sonam D Sherpa

Alok Ranjan

Sergey Alexandrovich Voronin

Mingmei Wang

Yoshio Ishikawa

Vinayak Rastogi

Takashi Enomoto

Jason Marion

Erdinc Karakas

In one exemplary embodiment, described herein is an ALE process for etching an oxide. In one embodiment, the oxide is silicon oxide. The ALE modification step includes the use of a carbon tetrafluoride (CF4) based plasma. This modification step preferentially removes oxygen from the surface of the silicon oxide, providing a silicon rich surface. The ALE removal step includes the use of a hydrogen (H2) based plasma. This removal step removes the silicon enriched monolayer formed in the modification step. The silicon oxide etch ALE process utilizing CF4 and H2 steps may be utilized in a wide range of substrate process steps. For example, the ALE process may be utilized for, but is not limited to, self-aligned contact etch steps, silicon fin reveal steps, oxide mandrel pull steps, oxide spacer trim, and oxide liner etch.

Method of atomic layer etching of oxide

Embodiments provide area-selective etching of silicon nitride for the manufacture of microelectronic workpieces through sequential exposure of silicon nitride layers to hydrogen ions/radicals followed by fluorine ions/radicals using beam delivery techniques such as ion beam and/or neutral beam techniques. The area-selective etch processes are anisotropic when hydrogen ions are used and are isotropic when hydrogen radicals are used. Further, sputtering of material onto a substrate for a microelectronic workpiece is not required for the disclosed embodiments. Further, by using ion beam and/or neutral beam techniques, area-selective etching of silicon nitride is achieved as opposed to the large-area etching provided by prior plasma processing techniques. For certain embodiments, the ion/neutral beam techniques described herein are used to fabricate silicon nitride hard masks without requiring the use of any mask.

Method for area-selective etching of silicon nitride layers for the manufacture of microelectronic workpieces

An isotropic plasma etch process for etching silicon oxide is provided. In an embodiment, a first step, a modification step, includes the use of a fluorocarbon based plasma. This modification step provides for the formation of an interface layer and the deposition of a fluorocarbon film on the surface of the silicon oxide. Then, a second step, a removal step includes the use of an oxygen (O2) based plasma. This removal step removes the fluorocarbon film and the interface layer. To promote isotropic etching, the plasma process is performed with little or no low frequency bias power applied to the system. Thus, ion attraction to the substrate is minimized by providing no low frequency power. Further, relatively high pressures are maintained so as to further promote isotropic behavior.

Method of isotropic etching of silicon oxide utilizing fluorocarbon chemistry

Embodiments provide isotropic and selective etching of silicon nitride layers for the manufacture of microelectronic workpieces through sequential exposure of silicon nitride layers to plasma including hydrogen radicals and plasma including fluorine radicals. For example, the sequential application of plasma etch steps can use: (1) a first plasma gas including hydrogen (H) and argon (Ar), and (2) a second plasma gas including nitrogen trifluoride (NF), oxygen (O), and Ar. These plasma gases are ignited within a processing region or chamber under sufficient pressure to generate the hydrogen radicals and the fluorine radicals. Other plasma gas chemistries can also be used under sufficient pressures to generate alternating application of hydrogen radicals and fluorine radicals.

Method of etching silicon nitride layers for the manufacture of microelectronic workpieces

Plasma processing methods that provide for conformal etching of silicon nitride while also providing selectivity to another layer are described. In one embodiment, an etch is provided that utilizes gases which include fluorine, nitrogen, and oxygen, for example a gas mixture of SF, Nand Ogases. Specifically, a plasma etch utilizing SF, Nand Ogases at high pressure with no bias is provided. The process accelerates silicon nitride etching by chemical reactions of [NO]molecules from the plasma and [N] atoms from silicon nitride film. The etch provides a conformal (isotropic) etch that is selective to other materials such as silicon and silicon oxides (for example, but not limited to, silicon dioxide).

Method of conformal etching selective to other materials

A method of etching is described. The method includes forming a first chemical mixture by plasma-excitation of a first process gas containing an inert gas and at least one additional gas selected from the group consisting of He and H, and exposing the first material on the substrate to the first chemical mixture to modify a first region of the first material. Thereafter, the method includes forming a second chemical mixture by plasma-excitation of a second process gas containing an inert gas and an additional gas containing C, H, and F, and exposing the first material on the substrate to the second plasma-excited process gas to selectively etch the first material, which contains silicon oxide, relative to the second material and remove the modified first material from the first region of the substrate.

Selective oxide etching method for self-aligned multiple patterning

A method of etching is described. The method includes forming a first chemical mixture by plasma-excitation of a first process gas containing an inert gas and at least one additional gas selected from the group consisting of He and H, and exposing the first material on the substrate to the first chemical mixture to modify a first region of the first material. Thereafter, the method includes forming a second chemical mixture by plasma-excitation of a second process gas containing an inert gas and an additional gas containing C, H, and F, and exposing the first material on the substrate to the second plasma-excited process gas to selectively etch the first material, which contains silicon nitride, relative to the second material and remove the modified first material from the first region of the substrate.

Selective nitride etching method for self-aligned multiple patterning

A method of etching is described. The method includes providing a substrate having a first material containing silicon nitride and a second material that is different from the first material, forming a first chemical mixture by plasma-excitation of a first process gas containing H and optionally a noble gas, and exposing the first material on the substrate to the first chemical mixture. Thereafter, the method includes forming a second chemical mixture by plasma-excitation of a second process gas containing N, F, O, and optionally a noble element, and exposing the first material on the substrate to the second plasma-excited process gas to selectively etch the first material relative to the second material.

Method of quasi-atomic layer etching of silicon nitride

A method of preparing a self-aligned block (SAB) structure is described. The method includes providing a substrate having raised features defined by a first material containing silicon nitride and a second material containing silicon oxide formed on side walls of the first material, and a third material containing an organic material covering some of the raised features and exposing some raised features according to a block pattern formed in the third material. The method further includes forming a first chemical mixture by plasma-excitation of a first process gas containing H and optionally a noble gas, and exposing the first material on the substrate to the first chemical mixture. Thereafter, the method includes forming a second chemical mixture by plasma-excitation of a second process gas containing N, F, O, and optionally a noble element, and exposing the first material on the substrate to the second plasma-excited process gas to selectively etch the first material relative to the second and third material.

Method of anisotropic extraction of silicon nitride mandrel for fabrication of self-aligned block structures

Embodiments of the invention describe substrate processing methods using non-polymerizing chemistry to preferentially etch silicon nitride relative to other materials found in semiconductor manufacturing. According to one embodiment, a processing method includes providing in a plasma processing chamber a substrate containing a first material containing silicon nitride and a second material that is different from the first material, forming a plasma-excited process gas containing SF, and exposing the substrate to the plasma-excited process gas to preferentially etch the first material relative to the second material. In one example, the process gas can contain or consist of SFand Ar. In another example, the second material is selected from the group consisting of Si and SiO.

Method of preferential silicon nitride etching using sulfur hexafluoride

A method of etching is described. The method includes providing a substrate having a first material containing silicon nitride and a second material that is different from the first material, forming a first chemical mixture by plasma-excitation of a first process gas containing H and optionally a noble gas, and exposing the first material on the substrate to the first chemical mixture. Thereafter, the method includes forming a second chemical mixture by plasma-excitation of a second process gas containing S and F, and optionally a noble element, and exposing the first material on the substrate to the second plasma-excited process gas to selectively etch the first material relative to the second material.

Embodiments of the invention provide a substrate processing method for selective SiN etching relative to other layers used in semiconductor manufacturing. According to one embodiment, the substrate processing method includes providing in a plasma processing chamber a substrate containing a first material containing silicon nitride and a second material that is different from the first material, forming a plasma-excited process gas containing NFand O, and exposing the substrate to the plasma-excited process gas to selectively etch the first material relative to the second material. According to one embodiment, the second material may be selected from the group consisting of Si, SiO, and a combination thereof.

Method of selective silicon nitride etching

According to one embodiment, a substrate processing method includes providing a substrate containing Si raised features, depositing a conformal film on the Si raised features, and performing a spacer etch process that removes horizontal portions of the conformal film while substantially leaving vertical portions of the conformal film to form sidewall spacers on the Si raised features, the performing including a) exposing the substrate to a plasma-excited first process gas consisting of Hgas and optionally an inert gas, and b) exposing the substrate to a plasma-excited second process gas containing i) NF, O, H, and Ar, ii) NF, O, and H, iii) NFand O, iv) NF, O, and Ar, v) NFand H, or vi) NF, H, and Ar. The method further includes removing the Si raised features while maintaining the sidewall spacers on the substrate. The removing may be performed using steps a) and b).

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Albany, NY, United States of America

Sonam D Sherpa