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CN-114496781-B - Tungsten film forming method

CN114496781BCN 114496781 BCN114496781 BCN 114496781BCN-114496781-B

Abstract

The invention discloses a tungsten film forming method which comprises the steps of placing a semiconductor substrate in a process chamber, introducing boron-containing gas into the process chamber for infiltration treatment, repeatedly and alternately executing a nucleation layer deposition step and a gas pulse treatment step to form a nucleation layer on the semiconductor substrate, wherein the nucleation layer deposition step comprises the steps of sequentially introducing the boron-containing gas and the tungsten-containing gas into the process chamber, introducing the boron-containing gas into the process chamber, forming the nucleation layer, introducing the tungsten-containing gas and hydrogen into the process chamber, and forming a tungsten film above the nucleation layer. In the scheme, the growth of the boron pollutant layer in the tungsten film forming process can be inhibited, the surface morphology of the nucleation layer is effectively improved, and the resistance of the finally formed tungsten film is reduced.

Inventors

  • Pu Xiangrong
  • BAI GUOBIN
  • GAO JIANFENG
  • WANG GUILEI
  • DING YUNLING
  • CUI HENGWEI

Assignees

  • 中国科学院微电子研究所
  • 真芯(北京)半导体有限责任公司

Dates

Publication Date
20260505
Application Date
20201028

Claims (9)

  1. 1. A tungsten film forming method, characterized by comprising: Placing a semiconductor substrate in a process chamber; introducing boron-containing gas into the process chamber for infiltration treatment; Repeatedly and alternately executing a nucleation layer deposition step and a gas pulse treatment step to form a nucleation layer on the semiconductor substrate, wherein the nucleation layer deposition step comprises sequentially introducing the boron-containing gas and the tungsten-containing gas into the process chamber; Forming a tungsten film over the nucleation layer; the step of repeatedly and alternately executing the nucleation layer deposition step and the gas pulse treatment step comprises the step of repeatedly and alternately executing the nucleation layer deposition step and the gas pulse treatment step according to the gas amount of the boron-containing gas introduced in each gas pulse treatment step, wherein for the two gas pulse treatment steps which are successively executed, the gas amount of the boron-containing gas introduced in the last gas pulse treatment step is larger than the gas amount of the boron-containing gas introduced in the next gas pulse treatment step.
  2. 2. The method of claim 1, wherein the introducing boron-containing gas into the process chamber for infiltration comprises: And introducing the boron-containing gas into the process chamber according to the gas flow of 100-500 sccm.
  3. 3. The method according to claim 1, wherein the amount of the boron-containing gas introduced in the next gas pulse treatment step is 70% -90% of the amount of the boron-containing gas introduced in the previous gas pulse treatment step.
  4. 4. The method of claim 1, wherein the pressure in the process chamber is less than or equal to 50Torr and the temperature is between 250 ℃ and 450 ℃ each time the nucleation layer deposition step is performed.
  5. 5. The method of claim 1, wherein the duration of each nucleation layer deposition step is 0.5 to 5 seconds.
  6. 6. The method of claim 1, wherein the iteratively alternating nucleation layer deposition steps and gas pulse treatment steps comprises: And repeatedly and alternately executing a nucleation layer deposition step and a gas pulse treatment step for preset times, wherein the preset times are 3-10 times.
  7. 7. The method of claim 1, wherein the nucleation layer has a thickness of 10 to 30 angstroms.
  8. 8. The method of claim 1, wherein the introducing the tungsten-containing gas and hydrogen gas into the process chamber forms a tungsten film over the nucleation layer by a chemical vapor deposition process comprising: And forming the tungsten film on the nucleation layer when the pressure of the process chamber is less than or equal to 50Torr and the temperature is 250-450 ℃.
  9. 9. The method of any one of claims 1-8, wherein the boron-containing gas is B 2 H 6 and the tungsten-containing gas is WF 6 .

Description

Tungsten film forming method Technical Field The invention relates to the field of semiconductors, in particular to a tungsten film forming method. Background With the continuous development of science and technology, the size of semiconductor devices is smaller and smaller, and the requirement of size reduction on low resistance is stricter. A metal film, such as a tungsten film, is typically a nucleation layer that determines the resistance and reliability of the tungsten film. In the process of forming the tungsten film, a nucleation layer is formed first, and then the tungsten film is formed above the nucleation layer through hydrogen and tungsten-containing gas. Without a stable nucleation layer, it is difficult to form a reliable tungsten film. In the tungsten film process in the prior art, when a boron-containing gas is used for forming a nucleation layer, a boron pollutant layer appears, so that the surface morphology of the nucleation layer is poor, and the resistance of the finally formed tungsten film is too high. Disclosure of Invention The embodiment of the application solves the technical problem of too high tungsten film resistance caused by poor surface morphology of a nucleation layer in the prior art by providing the tungsten film forming method, and achieves the technical effect of improving the surface morphology of the nucleation layer. The application provides a tungsten film forming method, which comprises the following steps: Placing a semiconductor substrate in a process chamber; introducing boron-containing gas into the process chamber for infiltration treatment; Repeatedly and alternately executing a nucleation layer deposition step and a gas pulse treatment step to form a nucleation layer on the semiconductor substrate, wherein the nucleation layer deposition step comprises sequentially introducing the boron-containing gas and the tungsten-containing gas into the process chamber; A tungsten film is formed over the nucleation layer. Optionally, the introducing the boron-containing gas into the process chamber for infiltration treatment includes: And introducing the boron-containing gas into the process chamber according to the gas flow of 100-500 sccm. Optionally, the repeatedly and alternately performing the nucleation layer deposition step and the gas pulse treatment step includes: And repeatedly and alternately executing a nucleation layer deposition step and a gas pulse treatment step according to the gas amount of the boron-containing gas introduced in each gas pulse treatment step, wherein for two gas pulse treatment steps which are successively executed, the gas amount of the boron-containing gas introduced in the last gas pulse treatment step is larger than the gas amount of the boron-containing gas introduced in the next gas pulse treatment step. Optionally, the gas amount of the boron-containing gas introduced in the next gas pulse treatment step is 70% -90% of the gas amount of the boron-containing gas introduced in the previous gas pulse treatment step. Optionally, the pressure of the process chamber is less than or equal to 50Torr and the temperature is 250 ℃ to 450 ℃ when each nucleation layer deposition step is performed. Optionally, the duration of each nucleation layer deposition step is 0.5-5 s. Optionally, the repeatedly and alternately performing the nucleation layer deposition step and the gas pulse treatment step includes: And repeatedly and alternately executing a nucleation layer deposition step and a gas pulse treatment step for preset times, wherein the preset times are 3-10 times. Optionally, the thickness of the nucleation layer is 10-30 angstroms. Optionally, the introducing the tungsten-containing gas and hydrogen into the process chamber forms a tungsten film over the nucleation layer by a chemical vapor deposition process, including: And forming the tungsten film on the nucleation layer when the pressure of the process chamber is less than or equal to 50Torr and the temperature is 250-450 ℃. Optionally, the boron-containing gas is B 2H6 and the tungsten-containing gas is WF 6. The technical scheme provided by the embodiment of the application comprises the steps of placing a semiconductor substrate in a process chamber, introducing boron-containing gas into the process chamber for infiltration treatment, repeatedly and alternately performing a nucleation layer deposition step and a gas pulse treatment step to form a nucleation layer on the semiconductor substrate, wherein the nucleation layer deposition step comprises sequentially introducing boron-containing gas and tungsten-containing gas into the process chamber, and the gas pulse treatment step comprises introducing the boron-containing gas into the process chamber, and after forming the nucleation layer, introducing tungsten-containing gas and hydrogen into the process chamber to form a tungsten film above the nucleation layer. In the scheme, the boron-containing gas is adopted for infiltration