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KR-20260064466-A - LOW DENSITY PECVD DEPOSITED HYDROGENATED AMORPHOUS CARBON FILMS WITH HIGH BREAKDOWN VOLTAGES

KR20260064466AKR 20260064466 AKR20260064466 AKR 20260064466AKR-20260064466-A

Abstract

A method of plasma-enhanced chemical vapor deposition is provided, comprising the steps of: supporting a wafer in a reactor chamber on a wafer support; generating a plasma from acetylene gas, hydrogen gas, and argon gas using a high-frequency RF power supply; and depositing an amorphous hydride carbon film on the wafer; wherein during the deposition step, the reactor chamber pressure is within the range of 1 Torr to 6 Torr; and during the deposition step, the wafer support temperature is between 200 degrees Celsius and 350 degrees Celsius; thereby providing a dielectric layer on the wafer that exhibits low leakage currents less than 1.0E-07 A/ cm² and high breakdown voltage greater than 6 MV/cm at an operating voltage of 2 MV/cm.

Inventors

  • 크룩 캐서린
  • 로일 윌리엄
  • 루신스카 에밀리아
  • 파핏 몰리

Assignees

  • 에스피티에스 테크놀러지스 리미티드

Dates

Publication Date
20260507
Application Date
20250610
Priority Date
20241031

Claims (20)

  1. In a method of plasma-enhanced chemical vapor deposition, A step of supporting a wafer in a reactor chamber on a wafer support; A step of generating plasma from acetylene gas, hydrogen gas, and argon gas using a high-frequency RF power supply; and Step of depositing an amorphous hydrogenated carbon film on the wafer Including; During the above deposition step, the reactor chamber pressure is within the range of 1 Torr to 6 Torr; During the above deposition step, the wafer support temperature is between 200 and 350 degrees Celsius; A method of plasma-enhanced chemical vapor deposition, wherein the deposited amorphous hydrogenated carbon film provides a dielectric layer on the wafer exhibiting low leakage currents less than 1.0E-07 A/ cm² and high breakdown voltage greater than 6 MV/cm at an operating voltage of 2 MV/cm.
  2. A method of plasma-enhanced chemical vapor deposition according to claim 1, wherein the temperature of the wafer support during the deposition step is within the range of 225 degrees to 325 degrees.
  3. A method of plasma-enhanced chemical vapor deposition according to claim 2, wherein the temperature of the wafer support during the deposition step is within the range of 250 degrees to 300 degrees.
  4. A method of plasma-enhanced chemical vapor deposition according to any one of claims 1 to 3, wherein the plasma is generated using an RF power supply of 13.56 MHz.
  5. A method of plasma-enhanced chemical vapor deposition according to any one of claims 1 to 4, wherein the plasma is generated using an RF-driven showerhead and an electrically grounded wafer support.
  6. A method of plasma-enhanced chemical vapor deposition according to any one of claims 1 to 5, wherein the plasma is generated using an RF power supply providing power between 500 W and 1500 W.
  7. A method of plasma-enhanced chemical vapor deposition according to any one of claims 1 to 6, wherein the reactor chamber pressure is within the range of 1.5 Torr to 5 Torr.
  8. A method of plasma-enhanced chemical vapor deposition carried out in a capacitively coupled reactor, in any one of claims 1 to 7.
  9. A method of plasma-enhanced chemical vapor deposition, wherein, in any one of claims 1 to 8, the acetylene gas is supplied to the reactor chamber at a flow rate within the range of 100 sccm to 600 sccm.
  10. A method of plasma-enhanced chemical vapor deposition according to claim 8, wherein the acetylene gas is supplied to the reactor chamber at a flow rate within the range of 200 sccm to 550 sccm.
  11. A method of plasma-enhanced chemical vapor deposition, wherein, in any one of claims 1 to 10, the hydrogen gas is supplied to the reactor chamber at a flow rate within the range of 100 sccm to 600 sccm.
  12. A method of plasma-enhanced chemical vapor deposition according to claim 10, wherein the hydrogen gas is supplied to the reactor chamber at a flow rate within the range of 250 sccm to 550 sccm.
  13. A method of plasma-enhanced chemical vapor deposition, wherein, in any one of claims 1 to 12, the argon gas is supplied to the reactor chamber at a flow rate within the range of 200 sccm to 1000 sccm.
  14. A method of plasma-enhanced chemical vapor deposition according to claim 12, wherein the argon gas is supplied to the reactor chamber at a flow rate within the range of 300 sccm to 900 sccm.
  15. A method of plasma-enhanced chemical vapor deposition according to any one of claims 1 to 14, wherein the wafer is a 300 mm silicon wafer.
  16. A method of plasma-enhanced chemical vapor deposition according to any one of claims 1 to 15, wherein the deposited film has a thickness between 150 nm and 1000 nm.
  17. A method of plasma-enhanced chemical vapor deposition according to any one of claims 1 to 16, wherein the deposited amorphous hydrogenated carbon film has a density of 1.6 g/cc to 1.8 g/cc.
  18. In a plasma-enhanced chemical vapor deposition system configured to carry out the method of any one of claims 1 to 16, Reactor chamber; Gas inlets arranged to supply acetylene gas, hydrogen gas, and argon gas to the reactor chamber; A wafer support configured to support a wafer within the reactor chamber; RF power supply coupled to the above reactor chamber A system including
  19. A system according to claim 17, wherein the wafer support is grounded and arranged to be heated resistively, thereby heating the wafer.
  20. A system according to claim 17 or 18, further comprising a cooling mechanism associated with the wafer support and configured to cool the wafer.

Description

Low Density PECVD Deposited Hydrogenated Amorphous Carbon Films with High Breakdown Voltages The present invention relates to a method of plasma-enhanced chemical vapor deposition (PECVD), in particular to a method for depositing an amorphous hydrogenated carbon thin film on a wafer having excellent electrical isolation properties. The present invention also relates to a PECVD apparatus configured to carry out such a method. Plasma-enhanced chemical vapor deposition (PECVD) techniques can be used to deposit carbon thin films for various purposes requiring carbon coatings. The films may include, for example, diamond-like carbon films, 2D carbon layer films, and polymer films. It will be recognized that a "thin film" is a film having a thickness not greater than a few micrometers. The films tend to be disordered or amorphous for the most practical process parameters. They are typically defined as amorphous carbon (a-C) or amorphous hydrogenated carbon (a-C:H) films. For example, dense amorphous hydrogenated carbon films (i.e., having a density of 1.8 g/cc or higher) can be used to provide a hard diamond-like carbon (DLC) protective layer on a substrate for advanced patterning applications, for example, providing improved etch selectivity compared to conventional SiO2 or SiN masks. For reasons of manufacturing efficiency and ease, it is desirable to deposit films at low temperatures below 350 degrees Celsius. It will be understood that the temperature referred to is the wafer temperature/wafer support temperature. It would be beneficial to develop suitable methods for depositing amorphous hydrogenated carbon films to be used as dielectric films in interconnection schemes. This would provide alternatives to conventional films such as SiO2 , SiN, SiC, and SiCN films. For economic reasons, the films must be deposited at low temperatures and at an acceptable deposition rate. A method of plasma-enhanced chemical vapor deposition is provided in a first aspect of the present invention. The method comprises the steps of: supporting a wafer in a reactor chamber on a wafer support; generating a plasma from acetylene gas, hydrogen gas, and argon gas using a high-frequency RF power supply; and depositing an amorphous hydride carbon film on the wafer. During the deposition step, the reactor chamber pressure is within the range of 1 Torr to 6 Torr and the wafer support temperature is between 200°C and 350°C, thereby providing a dielectric layer on the wafer in which the deposited amorphous hydride carbon film exhibits low leakage currents less than 1.0E-07 A/ cm² and a high breakdown voltage greater than 6 MV/cm at an operating voltage of 2 MV/cm. The inventors recognized that the electrical isolation properties of the deposited film must be suitable for use as a dielectric film in an interconnection scheme. Accordingly, a PECVD process was designed using acetylene, hydrogen, and argon gases to deposit an amorphous hydrogenated carbon film that displays low leakage currents and high breakdown voltage at a sufficiently fast deposition rate. This was achieved with a high-frequency power supply, a reactor chamber pressure in the range of 1 Torr to 6 Torr, and a wafer temperature between 200°C and 350°C. Although lower plate/wafer support temperatures (< 350°C) proved to enable fast deposition rates, it was found that below a certain temperature, the electrical performance of the film deteriorated. It was found that a suitable temperature for the plate to enable an acceptable deposition rate while still providing suitable electrical properties is between 200°C and 350°C. It is suggested that amorphous hydrogenated carbon films deposited below 200°C and above 350°C using C₂H₂ /Ar/ H₂ chemistry and high-frequency RF plasma, without being bound by arbitrary conjectures, cause structural changes in the film, which degrades the dielectric properties of the film. While higher density films containing excess sp2 bonding (determined from FTIR sp3/sp2 ratios) are deposited at lower temperatures, resulting in degraded dielectric properties, insufficient hydrogen may be incorporated into the film at higher temperatures to adequately passivate the dangling bonds within the low-density aC matrix, again producing degraded dielectric properties compared to the films. Optionally, the wafer temperature is within the range of 225 to 325 degrees Celsius, more preferably within the range of 250 to 300 degrees Celsius. It has been found that the density of the film depends on the temperature, and that the density of the film affects the electrical performance of the film. It has been found that a narrow range of densities corresponding to temperatures between 225 and 325, more optimally between 250 and 300, provides optimal electrical characteristics. Plasma is generated using a high-frequency RF power supply, i.e., a power supply exceeding 1 MHz, typically greater than 2 MHz. Optionally, plasma is generated using an RF power supply of 13.56 MHz. I