Method for forming silicon nitride film selectively on sidewalls of trenches

Patent metadata

Field	Value
Publication number	US-2019057857-A1
Application number	US-201816167225-A
Country	US
Kind code	A1
Filing date	Oct 22, 2018
Priority date	Feb 19, 2016
Publication date	Feb 21, 2019
Grant date	—

Abstract

A method for fabricating a layer structure in a trench includes: simultaneously forming a dielectric film containing a Si—N bond on an upper surface, and a bottom surface and sidewalls of the trench, wherein a top/bottom portion of the film formed on the upper surface and the bottom surface and a sidewall portion of the film formed on the sidewalls are given different chemical resistance properties by bombardment of a plasma excited by applying voltage between two electrodes between which the substrate is place in parallel to the two electrodes; and substantially removing the sidewall portion of the film by wet etching which removes the sidewall portion of the film more predominantly than the top/bottom portion according to the different chemical resistance properties.

First claim

We/I claim:

1 . A method for fabricating a layer structure constituted by a dielectric film containing a Si—N bond in a recess formed in a substrate, comprising:
(i) simultaneously forming a dielectric film containing a Si—N bond on an upper surface and a bottom surface and a sidewall of the recess, wherein a top/bottom portion of the dielectric film formed on the upper surface and the bottom surface and a sidewall portion of the dielectric film formed on the sidewall are given different chemical resistance properties by bombardment of a plasma excited by applying voltage in a reaction space between two electrodes between which the substrate is placed in parallel to the two electrodes; and
(ii) substantially removing selectively the sidewall portion of the dielectric film among the top/bottom portion and the sidewall portion of the dielectric film by etching which removes the sidewall portion of the dielectric film more predominantly than the other according to the different chemical resistance properties,
wherein the plasma in step (i) is a capacitively coupled plasma (CCP) which is excited by applying RF power to one of the two electrodes, wherein plasma density in step (i) is adjusted in a manner rendering the chemical resistance properties of the top/bottom portion of the dielectric film higher than the chemical resistance properties of the sidewall portion of the dielectric film, and
wherein the plasma density is modulable as a function of a ratio of high frequency RF power to a total of high frequency RF power and low frequency RF power constituting the RF power, wherein the plasma density decreases when increasing the ratio, wherein in step (i), solely the high frequency RF power is used, and the ratio is one, wherein the high-frequency RF power has a frequency of 1 MHz or higher, and the low-frequency RF power has a frequency of less than 1 MHz.

2 . The method according to claim 1 , wherein the plasma is a plasma of Ar, N 2 , or O 2 .

3 . The method according to claim 1 , wherein in step (i), a halogenated silane is used as a precursor.

4 . The method according to claim 1 , wherein the etching is the wet etching, which is conducted using a solution of hydrogen fluoride (HF) or phosphoric acid.

Assignees

• Asm Ip Holding Bv

Inventors

• Ishikawa Dai
• Fukazawa Atsuki
• Shiba Eiichiro
• Ueda Shinya
• Ebisudani Taishi
• Chun SeungJu
• Yoo YongMin
• Min Yoonki
• Kim Seyong
• Choi Jongwan

Classifications

• H10P50/283

  by chemical means · CPC title

• H10P14/6682

  the compound being a silane, e.g. disilane, methylsilane or chlorosilane · CPC title

• H10P14/6532

  by exposure to a plasma · CPC title

• H10P14/6339

  deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD · CPC title

• H10P14/6336

  in the presence of a plasma [PECVD] · CPC title