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CN-121992371-A - Method for reducing stress of high-temperature deposited film and application thereof

CN121992371ACN 121992371 ACN121992371 ACN 121992371ACN-121992371-A

Abstract

The invention discloses a method for reducing stress of a high-temperature deposited film and application thereof, wherein the method comprises the following steps: when the high-temperature thin film deposition process is carried out, the substrate is deformed by heating, then a first thin film is deposited on the surface of the deformed substrate, and then the substrate with the first thin film is deformed and restored by cooling, so that the first stress existing in the first thin film is released. The invention can avoid the problem that the film layer is likely to crack and peel off from the substrate after the film deposited at high temperature, which causes difficult patterning when manufacturing corresponding devices.

Inventors

  • Ning Kunqi

Assignees

  • 上海集成电路研发中心有限公司
  • 张江国家实验室

Dates

Publication Date
20260508
Application Date
20241028

Claims (10)

  1. 1. A method for reducing stress in a high temperature deposited film comprising: When the high-temperature thin film deposition process is carried out, the substrate is deformed by heating, then a first thin film is deposited on the surface of the deformed substrate, and then the substrate with the first thin film is deformed and restored by cooling, so that the first stress existing in the first thin film is released.
  2. 2. The method of reducing stress in a high temperature deposited film according to claim 1, wherein an applied second stress is generated on a first surface of said substrate by heating, said substrate being deformed as a whole, and said first film being deposited on a second surface of said substrate opposite to said first surface, wherein said second stress is of the same type as said first stress.
  3. 3. The method of reducing stress in a high temperature deposited film according to claim 2, wherein the stress types of the first stress and the second stress include tensile stress.
  4. 4. The method according to claim 3, wherein the first stress is released by forming a second thin film on the first surface before the high temperature deposition process, the second thin film having a thermal expansion coefficient smaller than that of the substrate, so that a tensile stress applied to the first surface is formed when the high temperature deposition process is performed and the substrate is heated, the substrate is deformed to have a shape in which an amount of deformation on the first surface is smaller than that on the second surface, and by depositing the first thin film having a tensile stress on the deformed second surface of the substrate, and recovering the deformation of the substrate by a temperature reduction, the first thin film on the second surface is contracted.
  5. 5. The method according to claim 4, wherein before forming the second film, a third film is further formed on the first surface, the second film is formed on the surface of the third film, the third film has a thermal expansion coefficient between that of the substrate and that of the second film, and the thickness of the second film is larger than that of the third film, or the thermal expansion coefficient of the third film is equal to that of the second film, and/or a fourth film is further formed on the second surface, the first film is formed on the surface of the fourth film, the thermal expansion coefficient of the fourth film is equal to that of the second film, and the thickness of the second film is larger than that of the fourth film, or the thermal expansion coefficient of the fourth film is larger than or equal to that of the substrate.
  6. 6. The method of reducing stress in a high temperature deposited film according to claim 5, wherein the substrate comprises a silicon substrate or an SOI substrate, the second film comprises a silicon dioxide film, and/or the third film and/or the fourth film comprises a silicon dioxide film.
  7. 7. The method of claim 5, wherein the second film has a thickness of 0.5-1 μm.
  8. 8. The method according to claim 1, wherein the first thin film comprises a silicon nitride thin film, the high temperature deposition thin film process comprises a furnace tube deposition thin film process, the silicon nitride thin film is deposited in the furnace tube by adopting an LPCVD process, and the atomic ratio of silicon to nitrogen in the formed silicon nitride thin film is close to 3:4 of ideal condition by introducing excessive NH 3 , and/or the process temperature when the silicon nitride thin film is deposited is 700-900 ℃.
  9. 9. Use of a method of reducing stress in a high temperature deposited film as claimed in any of claims 1 to 8, the use comprising the preparation of a passive device using a first film after release of a first stress.
  10. 10. The use of claim 9, wherein the passive device comprises a silicon nitride waveguide.

Description

Method for reducing stress of high-temperature deposited film and application thereof Technical Field The invention relates to the technical field of semiconductor integrated circuit processes, in particular to a method for reducing stress of a high-temperature deposited film and application thereof. Background Certain materials tend to exhibit greater stress after deposition using a high temperature furnace process and formation of a thin film on the substrate. And if such stresses are not expected, they can have an impact on subsequent processes. For example, in the conventional LPCVD silicon nitride process using a furnace, the NH 3 in the reaction gas typically needs to be set to an excess, so that the atomic ratio of Si to N of the grown silicon nitride film is approximately 3:4 of ideal to obtain a satisfactory film refractive index when the silicon nitride device is subsequently fabricated. However, the silicon nitride film grown under such process conditions is highly stressed, and when the silicon nitride film having the high stress is deposited to a thick thickness required for the device, problems of subsequent film cracking and peeling from the substrate may occur, resulting in difficulty in patterning in manufacturing the corresponding silicon nitride device. Disclosure of Invention The invention aims to overcome the defects in the prior art and provides a method for reducing the stress of a high-temperature deposited film and application thereof. In order to achieve the above purpose, the technical scheme of the invention is as follows: The invention provides a method for reducing stress of a high-temperature deposited film, which comprises the following steps: When the high-temperature thin film deposition process is carried out, the substrate is deformed by heating, then a first thin film is deposited on the surface of the deformed substrate, and then the substrate with the first thin film is deformed and restored by cooling, so that the first stress existing in the first thin film is released. Further, by heating, an applied second stress is generated on the first surface of the substrate, so that the substrate is integrally deformed, and then the first film is deposited on the second surface of the substrate opposite to the first surface, wherein the second stress is the same as the first stress in type. Further, the stress types of the first stress and the second stress include tensile stress. Further, before the high temperature thin film deposition process is performed, a second thin film is formed on the first surface, the thermal expansion coefficient of the second thin film is smaller than that of the substrate, so that when the high temperature thin film deposition process is performed and the substrate is heated, tensile stress applied to the first surface is formed, the substrate is deformed and shaped due to the fact that the deformation amount on the first surface is smaller than that on the second surface, the first thin film with tensile stress is deposited on the second surface of the deformed substrate, and the first thin film on the second surface is contracted by utilizing deformation recovery of the substrate caused by temperature reduction, so that the first stress existing in the first thin film is released. Further, before forming the second film, a third film is further formed on the first surface, the second film is formed on the surface of the third film, the thermal expansion coefficient of the third film is between the thermal expansion coefficient of the substrate and the thermal expansion coefficient of the second film, the thickness of the second film is larger than the thickness of the third film, or the thermal expansion coefficient of the third film is equal to the thermal expansion coefficient of the second film, and/or a fourth film is further formed on the second surface, the thermal expansion coefficient of the first film is equal to the thermal expansion coefficient of the second film, and the thickness of the second film is larger than the thickness of the fourth film, or the thermal expansion coefficient of the fourth film is larger than the thermal expansion coefficient of the substrate. Further, the substrate includes a silicon substrate or an SOI substrate, the second film includes a silicon dioxide film, and/or the third film and/or the fourth film includes a silicon dioxide film. Further, the thickness of the second film is 0.5-1 μm. Further, the first film comprises a silicon nitride film, the high-temperature deposition film process comprises a furnace tube deposition film process, the silicon nitride film is deposited in the furnace tube by adopting an LPCVD process, and the atomic ratio of silicon to nitrogen in the formed silicon nitride film is close to 3:4 of ideal conditions by introducing excessive NH 3, and/or the process temperature during the deposition of the silicon nitride film is 700-900 ℃. The invention also provides an applicati