Method for preparing semiconductor element with silicon nitride passivation dielectric film and obtained semiconductor element

Abstract

The invention relates to a method for preparing a semiconductor element with a silicon nitride passivation dielectric film and the obtained semiconductor element, and the method comprises the steps: forming the silicon nitride passivation dielectric film on the surface of the semiconductor element in a plasma enhanced chemical vapor deposition mode; the plasma enhanced chemical vapor deposition conditions are as follows: the pressure is more than 2.0 Torr, the radio frequency power is more than 500W, and the flow of ammonia gas is greater than that of nitrogen plasma. The silicon nitride passivation dielectric film prepared by adopting the method disclosed by the invention has proper hydrogen atom content and compact degree, and in the subsequent annealing process, hydrogen generated in the heating process can diffuse and repair device defects in the previous process.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor manufacturing, and more particularly, to a method for manufacturing a semiconductor device with a silicon nitride passivation dielectric film and the resulting semiconductor device. Background Art

[0002] In modern times, microelectronics technology has become the foundation of the entire information industry and an important symbol reflecting a country's comprehensive strength and economic development level. With the development of integrated circuit technology, chips with high speed, high device density, low power consumption, and low cost have increasingly become the main products of very large scale integrated circuit manufacturing.

[0003] In the field of semiconductor manufacturing, a silicon nitride passivation dielectric film can be used to prevent the surface of a semiconductor device from being contaminated by the environment. Since subsequent manufacturing steps require an annealing process and the diffusion of hydrogen during the heating process to repair device defects in the previous process, the existing silicon nitride passivation dielectric film is too dense, and hydrogen cannot diffuse during the heating process of the annealing process, resulting in the inability to repair device defects. Summary of the Invention

[0004] The purpose of the present disclosure is to provide a method for manufacturing a semiconductor device with a silicon nitride passivation dielectric film and the resulting semiconductor device.

[0005] To achieve the above object, in a first aspect of the present disclosure, a method for manufacturing a semiconductor device with a silicon nitride passivation dielectric film is provided, the method comprising: forming a silicon nitride passivation dielectric film on the surface of the semiconductor device by plasma enhanced chemical vapor deposition;

[0006] The conditions for the plasma enhanced chemical vapor deposition include: a pressure of more than 2.0 Torr, a radio frequency power of more than 500 W, and a flow rate of ammonia greater than the flow rate of nitrogen plasma.

[0007] Optionally, the pressure is 2.0 - 6.0 Torr.

[0008] Optionally, the radio frequency power is 500 - 2000 W.

[0009] Optionally, the temperature of the plasma enhanced chemical vapor deposition is 300 - 500 °C.

[0010] Optionally, the raw materials for forming the silicon nitride passivation dielectric film further include silane, and the flow rate of the silane is 500 - 2000 sccm.

[0011] Optionally, the flow rate of the nitrogen plasma is 1000 - 10000 sccm.

[0012] Optionally, the flow rate of the ammonia is 1000 - 10000 sccm.

[0013] Optionally, the method further includes: annealing the semiconductor device having the silicon nitride passivation dielectric film.

[0014] Optionally, in the silicon nitride passivation dielectric film, the content of hydrogen atoms is 17% to 19% relative to the total number of hydrogen atoms, nitrogen atoms, and silicon atoms.

[0015] A second aspect of the present disclosure provides a semiconductor device prepared by the method described in the first aspect of the present disclosure.

[0016] By the above technical solution, the method of the present disclosure controls the pressure, power, and the flow rate of ammonia gas greater than the flow rate of nitrogen plasma during plasma enhanced chemical vapor deposition to prepare a silicon nitride passivation dielectric film having a specific hydrogen atom content and appropriate density, and does not affect the properties of the silicon nitride passivation dielectric film, such as refractive index, extinction coefficient, stress, etc. In the subsequent annealing process, hydrogen during the heating process can diffuse and repair device defects in the previous process.

[0017] Other features and advantages of the present disclosure will be described in detail in the subsequent specific implementation section. Specific Embodiments

[0018] The following details the specific embodiments of the present disclosure. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present disclosure, and are not intended to limit the present disclosure.

[0019] A first aspect of the present disclosure provides a method for preparing a semiconductor device having a silicon nitride passivation dielectric film, the method including: forming a silicon nitride passivation dielectric film on the surface of the semiconductor device by plasma enhanced chemical vapor deposition;

[0020] The conditions for the plasma enhanced chemical vapor deposition include: a pressure of 2.0 Torr or more, a radio frequency power of 500 W or more, and a flow rate of ammonia gas greater than the flow rate of nitrogen plasma.

[0021] The inventors of the present disclosure unexpectedly found that by controlling the pressure, power, and the flow rate of ammonia gas greater than the flow rate of nitrogen plasma during plasma enhanced chemical vapor deposition, a silicon nitride passivation dielectric film having a specific hydrogen atom content can be prepared. The silicon nitride passivation dielectric film having the above specific hydrogen atom content has an appropriate density. As a protective layer of the semiconductor device and used in a process that requires an annealing process to repair device defects in the previous process, hydrogen can diffuse smoothly, and the method of the present disclosure does not affect the properties of the silicon nitride passivation dielectric film, such as refractive index, extinction coefficient, stress, etc.

[0022] To obtain a silicon nitride passivation dielectric film with a suitable hydrogen atom content, according to an embodiment of the present disclosure, the flow rate ratio of ammonia gas to nitrogen plasma is (1.03 - 1.2):1.

[0023] To obtain a silicon nitride passivation dielectric film with a suitable hydrogen atom content, according to an embodiment of the present disclosure, the pressure is 2.0 - 6.0 Torr, for example, it can be 2.0 Torr, 3.0 Torr, 4.0 Torr, 5.0 Torr, 6.0 Torr, etc.

[0024] To obtain a silicon nitride passivation dielectric film with a suitable hydrogen atom content, according to an embodiment of the present disclosure, the RF power is 500 - 2000 W, for example, it can be 500 W, 800 W, 1000 W, 1200 W, 2000 W, etc.

[0025] According to an embodiment of the present disclosure, the temperature of plasma enhanced chemical vapor deposition is 300 - 500 °C, for example, it can be 300 °C, 350 °C, 380 °C, 400 °C, 420 °C, 450 °C, 500 °C, etc.

[0026] To obtain a silicon nitride passivation dielectric film with a suitable hydrogen atom content, according to an embodiment of the present disclosure, the raw material for forming the silicon nitride passivation dielectric film further includes silane (SiH4), and the flow rate of silane is 500 - 2000 sccm, for example, it can be 500 sccm, 800 sccm, 1000 sccm, 1300 sccm, 1500 sccm, 2000 sccm, etc.

[0027] To obtain a silicon nitride passivation dielectric film with a suitable hydrogen atom content, according to an embodiment of the present disclosure, the flow rate of nitrogen plasma is 1000 - 10000 sccm, preferably 1000 - 5000 sccm, for example, it can be 1000 sccm, 1300 sccm, 2000 sccm, 2700 sccm, 3000 sccm, 3300 sccm, 4000 sccm, 5000 sccm, etc.

[0028] To obtain a silicon nitride passivation dielectric film with a suitable hydrogen atom content, according to an embodiment of the present disclosure, the flow rate of ammonia gas is 1000 - 10000 sccm, preferably 3000 - 10000 sccm, for example, it can be 3000 sccm, 3300 sccm, 4000 sccm, 5000 sccm, 6000 sccm, 6300 sccm, 7000 sccm, 8000 sccm, 9000 sccm, 10000 sccm, etc.

[0029] In the present disclosure, the thickness of the silicon nitride passivation dielectric film is set according to production requirements and can be controlled by the deposition time.

[0030] According to an embodiment of the present disclosure, the method further includes: annealing the semiconductor element with the silicon nitride passivation dielectric film, and the specific steps and conditions of annealing are conventional in the art.

[0031] According to an embodiment of the present disclosure, in the silicon nitride passivation dielectric film, relative to the total number of hydrogen atoms, nitrogen atoms, and silicon atoms, the content of hydrogen atoms is 17% - 19%; wherein, the content of hydrogen atoms is tested by a Fourier transform infrared spectrometer (FTIR), and the specific test method is conventional in the art; the silicon nitride passivation dielectric film with the above hydrogen atom content has a moderate density, and in the subsequent annealing process, hydrogen can diffuse smoothly to repair the defects of the device and improve the quality of the device.

[0032] According to a specific embodiment of the present disclosure, the method for preparing a semiconductor element with a silicon nitride passivation dielectric film in the present disclosure includes:

[0033] Forming a silicon nitride passivation dielectric film on the surface of the semiconductor element by plasma enhanced chemical vapor deposition (PECVD);

[0034] The conditions include: the pressure is above 2.0 Torr, preferably 2.0 - 6.0 Torr; the power is above 500 W, preferably 500 - 2000 W; the temperature is 300 - 500 °C;

[0035] The flow rate of silane (SiH4) is 500 - 2000 sccm, the flow rate of nitrogen plasma is 1000 - 10000 sccm, preferably 1000 - 5000 sccm, and the flow rate of ammonia is 1000 - 10000 sccm, preferably 3000 - 10000 sccm;

[0036] The flow rate of ammonia is greater than the flow rate of nitrogen plasma. Preferably, the flow rate ratio of ammonia to nitrogen plasma is (1.03 - 1.2):1.

[0037] The silicon nitride passivation dielectric film prepared by the above method has a specific hydrogen atom content and a suitable density. In the subsequent annealing process, hydrogen can diffuse during the heating process to repair the device defects in the previous process.

[0038] The second aspect of the present disclosure provides a semiconductor element prepared by the method described in the first aspect of the present disclosure.

[0039] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form.

[0040] The raw materials used in the examples were all obtained through commercial channels and were of analytical purity without special instructions.

[0041] Example 1

[0042] A semiconductor device with a silicon nitride passivation dielectric film was prepared by the following steps:

[0043] On the surface of the semiconductor device, a silicon nitride passivation dielectric film was formed by plasma-enhanced chemical vapor deposition;

[0044] The conditions included: a pressure of 5 Torr, a power of 1400 W, a temperature of 400 °C, a flow rate of silane of 1000 sccm, a flow rate of nitrogen plasma of 3000 sccm, and a flow rate of ammonia of 3300 sccm;

[0045] It was found by testing with a Fourier transform infrared spectrometer that the hydrogen atom content in the prepared silicon nitride passivation dielectric film was 17%.

[0046] Comparative Example 1

[0047] A semiconductor device with a silicon nitride passivation dielectric film was prepared using the same semiconductor device and method as in Example 1, except that:

[0048] The flow rate of nitrogen plasma was 6000 sccm and the flow rate of ammonia was 1100 sccm;

[0049] It was found by testing with a Fourier transform infrared spectrometer that the hydrogen atom content in the prepared silicon nitride passivation dielectric film was 14%.

[0050] The preferred embodiments of the present disclosure have been described in detail above. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0051] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any suitable manner. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.

[0052] Furthermore, any combination can be made between various different embodiments of the present disclosure as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A method for fabricating a semiconductor device having a silicon nitride passivation dielectric thin film, characterized in that, The method includes: forming a silicon nitride passivation dielectric film on the surface of the semiconductor element by plasma enhanced chemical vapor deposition; The conditions for the plasma enhanced chemical vapor deposition include: the pressure is above 2.0 Torr, the radio frequency power is above 500 W, and the flow rate of ammonia gas is greater than the flow rate of nitrogen plasma.

2. The method according to claim 1, wherein, The pressure is 2.0 - 6.0 Torr.

3. The method according to claim 1, wherein, The radio frequency power is 500 - 2000 W.

4. The method according to claim 1, wherein, The temperature of the plasma enhanced chemical vapor deposition is 300 - 500 °C.

5. The method according to claim 1, wherein, The raw materials for forming the silicon nitride passivation dielectric film further include silane, and the flow rate of the silane is 500 - 2000 sccm.

6. The method according to claim 1, wherein, The flow rate of the nitrogen plasma is 1000 - 10000 sccm.

7. The method according to claim 1, wherein, The flow rate of the ammonia gas is 1000 - 10000 sccm.

8. The method according to claim 1, wherein, The method further includes: annealing the semiconductor element having the silicon nitride passivation dielectric film.

9. The method according to claim 1, wherein, In the silicon nitride passivation dielectric film, the content of hydrogen atoms is 17% - 19% relative to the total number of hydrogen atoms, nitrogen atoms and silicon atoms.

10. A semiconductor device fabricated by the method according to any one of claims 1 to 9.