CN105154848A - Method for preparing nitrogen oxygen silicon thin film - Google Patents

Abstract

The preparation method of the silicon oxynitride thin film mainly solves the problems of high deposition temperature and difficult control of various indexes of the thin film by thermal oxidation and chemical method for vapor deposition in the prior art. Implementation steps: 1. Temperature control of the stage: the lower electrode precisely controls the temperature through a thermocouple; 2. Sample loading: the substrate is transferred into the reaction chamber through the automatic transfer system; 3. Ventilation: from the upper electrode in the reaction chamber, namely Spray head, feed gas; 4. Deposition: The radio frequency system provides radio frequency, and deposit the film through plasma technology; 5. Post-processing: Stop feeding the main reaction source silane, and use radio frequency to post-treat the film surface; 6. Pumping Vacuum: process stopped. After the reaction gas is mixed, it enters the reaction chamber through the shower head, and the reaction chamber introduces radio frequency power for deposition, and a highly dense film can be obtained. The invention can realize the deposition of thin films at different temperatures, and silicon nitride oxide thin films with different properties, different film thicknesses, different refractive indices and different extinction coefficients can be obtained by changing the reaction parameters. It can be widely used in the field of semiconductor thin film manufacturing and application technology.

Description

Preparation method of silicon oxynitride thin film

technical field

The invention relates to a method for preparing a silicon oxynitride film, specifically a method for depositing a silicon oxynitride film by using plasma chemical vapor deposition equipment, and belongs to the technical field of semiconductor film manufacture and application.

Background technique

In semiconductor integrated circuits, insulating dielectric films are used as inter-metal dielectric layers, passivation layers or anti-reflection layers, and play a very important role in the semiconductor manufacturing process. Silicon oxynitride film is a new type of film material with good optical properties, and it is mostly used in the anti-reflection layer of semiconductor integrated circuits. The traditional method of depositing silicon oxynitride film uses thermal oxidation and chemical vapor deposition, the deposition temperature is high, and the various indicators of the film are not easy to control.

At present, with the continuous development of semiconductor technology, the performance requirements of thin films in integrated circuits are getting higher and higher. Plasma chemical vapor deposition equipment is a new technology for depositing insulating materials. Using this technology to deposit silicon oxynitride thin films The temperature is low, and the preparation method is relatively simple. Through the adjustment of radio frequency and process parameters, different film properties can be obtained.

Contents of the invention

The purpose of the present invention is to solve the above problems, and mainly solve the problems of high deposition temperature and difficult control of various indexes of the film in the prior art using thermal oxidation and chemical methods for vapor deposition.

To achieve the above object, the present invention provides a method for preparing a silicon oxynitride film, which uses plasma chemical vapor deposition equipment to deposit a silicon oxynitride film, and films with different properties can be obtained by changing the reaction parameters.

The present invention is achieved through the following specific steps:

1) Stage temperature control: the lower electrode precisely controls the temperature through a thermocouple;

2) Sample loading: the substrate is introduced into the reaction chamber through the automatic transfer system;

3) Ventilation: from the upper electrode in the reaction chamber, that is, the shower head, gas silane, laughing gas, helium and nitrogen are introduced;

4) Deposition: The radio frequency is provided by the radio frequency system, and the thin film is deposited by plasma technology;

5) post-treatment: stop feeding the main reaction source silane, and use radio frequency to carry out post-treatment on the film surface;

6) Vacuuming: the process is stopped, and the reaction chamber is evacuated to vacuum.

Further, the method for preparing the silicon oxynitride film is characterized in that: the deposition temperature of the silicon oxynitride film can be from 150°C to 450°C.

Further, the preparation method of silicon oxynitride thin film is characterized in that: the reaction gas is silane, laughing gas, helium and nitrogen.

Further, the preparation method of silicon oxynitride thin film is characterized in that: the ratio of silane to laughing gas in the reaction gas is 1:1 to 1:5, the flow rate of silane is 100 sccm-500 sccm; the flow rate of laughing gas is 300 sccm-1500 sccm ; The flow rate of helium is 1000sccm-9000sccm, and the flow rate of nitrogen gas is 300sccm-7000sccm.

Further, the method for preparing the silicon oxynitride thin film is characterized in that the reaction pressure is 1-7 Torr.

Further, the method for preparing the silicon oxynitride thin film is characterized in that the distance between the upper and lower electrodes is controlled by moving the stage up and down.

Further, the preparation method of silicon oxynitride thin film is characterized in that: during the reaction process, the radio frequency power can be from 100w to 1000w.

Further, the method for preparing the silicon oxynitride thin film is characterized in that after the deposition is completed, the surface of the thin film is post-treated by radio frequency, and at this time, the main reaction source silane is stopped.

Further, the method for preparing the silicon oxynitride thin film is characterized in that the deposition rate of the thin film can reach 1000-4000A/min.

Furthermore, the method for preparing the silicon oxynitride thin film is characterized in that: the reaction substrate may be a silicon wafer or glass.

Beneficial effects and characteristics of the present invention are:

The method of plasma enhanced chemical vapor deposition used in the present invention is used to prepare silicon oxynitride thin films. The preparation method can realize the deposition of thin films at different temperatures. By changing the flow ratio of different gases, different film thicknesses and different refractive indices can be obtained. , SiON films with different extinction coefficients. It can be widely used in the field of semiconductor thin film manufacturing and application technology.

Description of drawings

Fig. 1 is the reaction chamber schematic diagram of equipment used in the present invention

Detailed ways

The deposition method of the present invention will be further described in detail below in conjunction with specific examples. The advantages and features of the present invention will become clearer from the following description. The present invention uses plasma-enhanced chemical vapor deposition equipment produced by Shenyang Tuojing Technology Co., Ltd. The reaction chamber system of the equipment is shown in Figure 1.

Example 1:

The first example of the present invention prepares the method for silicon oxynitride thin film, concrete steps are as follows:

1) The stage of the deposition chamber is as shown in the reaction chamber stage 2 in Figure 1, that is, the temperature of the heating plate is 400°C,

Its control method is to monitor and control the temperature in real time through thermocouples

2) Put the wafer 3 on the stage 2 of the reaction chamber, pass the gas silane, laughing gas, helium and nitrogen into the reaction chamber through the upper electrode shower head 1, and the gas flow rate is 300 sccm for silane; 1100sccm; 5000sccm for helium; 900sccm for nitrogen.

3) While the chamber is being ventilated, set the reaction chamber pressure to 3.5 torr, which is the reaction pressure during the deposition process;

4) On the basis of the ventilation step, the radio frequency is provided by the radio frequency system to start the film deposition process,

Using different RF reaction powers to deposit silicon oxynitride films, the results are shown in the following table:

Table 1

Example 1 shows that by changing the RF power of the reaction, the deposition rate of the film can be increased accordingly.

Implementation mode 2:

The second example of the present invention prepares the method for silicon oxynitride thin film, concrete steps are as follows:

1) The stage of the deposition chamber is as shown in the reaction chamber stage 2 in Figure 1, that is, the temperature of the heating plate is 400°C, and

The control method is to monitor and control the temperature in real time through thermocouples

2) Put the wafer 3 on the stage 2 of the reaction chamber, pass the gas silane, nitrous oxide, helium and nitrogen into the reaction chamber through the upper electrode shower head 1, and change the flow ratio of silane and nitrous oxide, 270/ 900, 285/1000, 300/1100, 315/1200 and 330/1300 sccm.

3) While the chamber is being ventilated, set the reaction chamber pressure to 3.5 torr, which is the reaction pressure during the deposition process;

4) On the basis of the aeration step, the radio frequency is provided by the radio frequency system, and the radio frequency power is 300W to start the film deposition process.

In this example, the results are as follows:

Table 2

Example 2 shows that by changing the flow ratio of the reaction gas silane and laughing gas, the deposition rate can also be changed, and at the same time the optical constants of the film can be changed to realize different applications of the film in semiconductor integrated circuits.

Claims (9)

1. a preparation method of silicon oxynitride film, is characterized in that: the method is realized by following specific steps: (1) Stage temperature control: the lower electrode precisely controls the temperature through a thermocouple; (2) Sample loading: the reaction substrate is introduced into the reaction chamber through the automatic transfer system; (3) Ventilation: from the upper electrode in the reaction chamber, that is, the shower head, gas silane, laughing gas, helium and nitrogen are introduced; (4) Deposition: The radio frequency is provided by the radio frequency system, and the thin film is deposited by plasma technology; (5) post-treatment: stop feeding the main reaction source silane, and use radio frequency to carry out post-treatment on the film surface; (6) Vacuuming: the process is stopped, and the reaction chamber is evacuated to vacuum. 2 . The method for preparing a silicon oxynitride film according to claim 1 , wherein the deposition temperature of the silicon oxynitride film is from 150° C. to 450° C.; the reaction pressure is 1-7 Torr. 3. The method for preparing a silicon oxynitride thin film according to claim 1, characterized in that: the reaction gas is silane, laughing gas, helium and nitrogen. 4. the preparation method of silicon oxynitride film as claimed in claim 1 is characterized in that: the ratio of silane and laughing gas in the reaction gas is 1:1 to 1:5, and the flow rate of silane is 100sccm-500sccm; The flow rate of gas is 300sccm-1500sccm; the flow rate of helium gas is 1000sccm-9000sccm; the flow rate of nitrogen gas is 300sccm-7000sccm. After the reaction gas is mixed, it enters the reaction chamber through the shower head, and the reaction chamber introduces radio frequency power for deposition, so that a highly dense film can be obtained. 5 . The method for preparing a silicon oxynitride thin film according to claim 1 , wherein the method is to control the distance between the upper and lower electrodes by moving the stage up and down. 6 . 6. The method for preparing silicon oxynitride film according to claim 1, characterized in that: during the reaction process, the radio frequency power ranges from 100w to 1000w. 7. The method for preparing a silicon oxynitride thin film according to claim 1, characterized in that: after the deposition, the surface of the thin film is post-treated by radio frequency, and at this time, the main reaction source silane is stopped. 8 . The method for preparing a silicon oxynitride thin film according to claim 1 , wherein the deposition rate of the thin film is 1000-4000 A/min. 9. The method for preparing a silicon oxynitride thin film according to claim 1, wherein the reaction substrate is made of silicon wafer or glass.