# US 10,373,840 B2 · Technique to deposit sidewall passivation for high aspect ratio cylinder etch

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- Number: US 10,373,840 B2
- Document ID: US10373840B2
- Status: Granted
- Kind: B2
- Application number: 15/157,322
- Filed: 2016-05-17
- Published: 2016-09-08
- Granted: 2019-08-06
- Earliest claimed: 2014-12-04
- Assignees: Lam Research Corporation
- Applicants: Lam Research Corporation
- Inventors: Eric A. Hudson; Dennis M. Hausmann; Joseph Scott Briggs
- Web page: https://patentgrep.com/patent/US10373840B2

## CPC

- H10P 50/242: {of Group IV materials}
- C23C 16/00: Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes (reactive sputtering or vacuum evaporation C23C14/00)
- C23C 16/045: {Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates}
- C23C 16/45525: {Atomic layer deposition [ALD]}
- H01J 37/32009: {Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources (plasma generation in general H05H1/24)}
- H01J 37/32091: {the radio frequency energy being capacitively coupled to the plasma}
- H01J 37/32449: {Gas control, e.g. control of the gas flow}
- H01J 37/32513: {Sealing means, e.g. sealing between different parts of the vessel}
- H01J 37/32577: {Electrical connecting means}
- H01J 37/32623: {Mechanical discharge control means}
- H01J 37/32651: {Shields, e.g. dark space shields, Faraday shields}
- H01J 37/32871: {Means for trapping or directing unwanted particles}
- H01J 37/32899: {Multiple chambers, e.g. cluster tools}
- H10P 50/283: {by chemical means}
- H01J 2237/334: Etching
- H10B 12/03: {Making the capacitor or connections thereto}
- H10B 41/27: the channels comprising vertical portions, e.g. U-shaped channels
- H10B 43/27: the channels comprising vertical portions, e.g. U-shaped channels
- H10P 14/6339: {deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD}
- H10P 14/683: {carbon-based polymeric organic materials, e.g. polyimides, poly cyclobutene or PVC}
- H10P 14/687: {the materials being fluorocarbon compounds, e.g. (CHxFy) n or polytetrafluoroethylene}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

Various embodiments herein relate to methods, apparatus and systems for forming a recessed feature in dielectric material on a semiconductor substrate. Separate etching and deposition operations are employed in a cyclic manner. Each etching operation partially etches the feature. Each deposition operation forms a protective coating on the sidewalls of the feature to prevent lateral etch of the dielectric material during the etching operations. The protective coating may be deposited using methods that result in formation of the protective coating along substantially the entire length of the sidewalls. The protective coating may be deposited using particular reactants and/or reaction mechanisms that result in substantially complete sidewall coating at relatively low temperatures without the use of plasma. In some cases the protective coating is deposited using molecular layer deposition techniques.

## Claims

### Claim 1

An apparatus for forming an etched feature in a stack on a semiconductor substrate, the stack comprising a dielectric material, the apparatus comprising:
one or more reaction chambers, wherein at least one reaction chamber is configured to perform etching and comprises a plasma generator, and wherein at least one reaction chamber is configured to perform deposition, each reaction chamber comprising:
an inlet for introducing process gases to the reaction chamber, and
an outlet for removing material from the reaction chamber; and
a controller configured to cause:
(a) generating an etching plasma comprising an etching reactant, exposing the substrate to the etching plasma, and partially etching the feature in the stack, wherein (a) is performed in the reaction chamber configured to perform etching;
(b) after (a), depositing a protective film on sidewalls of the feature by
(i) exposing the substrate to a first reactant and allowing the first reactant to adsorb onto the substrate,
(ii) exposing the substrate to a second reactant, wherein the first and second reactants react with one another to form the protective film, and
(iii) repeating (i) and (ii) in a cyclic manner until the protective film reaches a target thickness, wherein the protective film is an organic polymeric film and is deposited along substantially the entire depth of the feature, and wherein (b) is performed in the reaction chamber configured to perform deposition;
(c) repeating (a)-(b) until the feature is etched to a final depth, wherein the protective film deposited in (b) substantially prevents lateral etch of the feature during (a), and wherein the feature has an aspect ratio of about 5 or greater at its final depth.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the reaction chamber configured to perform etching is the same reaction chamber configured to perform deposition, such that both (a) and (b) occur in the same reaction chamber.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein the reaction chamber configured to perform etching is different from the reaction chamber configured to perform deposition, and wherein the controller is further configured to cause transferring the substrate between the reaction chamber configured to perform etching and the reaction chamber configured to perform deposition.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein the controller is configured to cause depositing the protective film in (b) without the use of plasma.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the protective film formed in (b) comprises a polyamide and/or a polyester.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein the controller is configured to cause purging the reaction chamber configured to perform deposition at least once during each iteration of operation (b).

### Claim 7 (depends on 6)

The apparatus of claim 6, wherein the controller is configured to cause purging the reaction chamber configured to perform deposition at least twice during each iteration of operation (b), a first purge occurring between delivery of the first reactant in (i) and subsequent delivery of the second reactant in (ii), and a second purge occurring between delivery of the second reactant in (ii) and subsequent delivery of the first reactant in a subsequent iteration of (i).

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein at the final depth the feature has (i) an aspect ratio of about 20 or greater, and (ii) a maximum critical dimension that is no more than about 10% greater than the critical dimension at the bottom of the feature.

### Claim 9 (depends on 1)

The apparatus of claim 1, wherein the controller is configured to cause repeating (a) and (b) at least one time, wherein (b) is performed using the same reactants during each iteration.

### Claim 10 (depends on 1)

The apparatus of claim 1, wherein the controller is configured to cause repeating (a) and (b) at least one time, wherein (b) is performed using a first set of reactants during a first iteration and a second set of reactants during a second iteration, wherein the first set of reactants differs from the second set of reactants.

### Claim 11 (depends on 1)

The apparatus of claim 1, wherein the first reactant comprises an acyl halide or an acid anhydride, and wherein the second reactant comprises at least one of a diamine, a diol, a thiol, and a trifunctional compound.

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein the first reactant comprises a diacyl chloride.

### Claim 13 (depends on 12)

The apparatus of claim 12, wherein the first reactant comprises malonyl chloride.

### Claim 14 (depends on 1)

The apparatus of claim 1, wherein the second reactant comprises a diamine.

### Claim 15 (depends on 14)

The apparatus of claim 14, wherein the second reactant comprises ethylenediamine.

### Claim 16 (depends on 15)

The apparatus of claim 15, wherein the first reactant comprises malonyl chloride.

### Claim 17 (depends on 1)

The apparatus of claim 1, wherein the first reactant comprises one or more materials selected from the group consisting of: ethanedioyl dichloride, malonyl chloride, succinyl dichloride, pentanedioyl dichloride, and maleic anhydride; and wherein the second reactant comprises one or more materials selected from the group consisting of: 1,2-ethanediamine, 1,3-propanediamine, 1,4-butanediamine, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, (±)-3-amino-1,2-propanediol, glycerol, bis(hexamethylene)triamine, melamine, diethylenetriamine, (±)-1,2,4-butanetriol, cyanuric chloride, and trimethylaluminum.