Annealing-free thin film preparation process for improving stress stability of silicon dioxide, silicon dioxide thin film product and application

Abstract

The invention provides an annealing-free thin film preparation process for improving stress stability of silicon dioxide, a silicon dioxide thin film product and application. The thin film preparation process comprises the following steps: providing a substrate, and forming a silicon dioxide film layer on the substrate by adopting a chemical vapor deposition method; plasma treatment is conducted on the surface of the silicon dioxide film layer, plasma in plasma treatment is a combination of plasma-state helium and plasma-state nitrogen, and the silicon dioxide film product is obtained. According to the method, plasma treatment is carried out on the silicon dioxide film through combination of helium and nitrogen, so that the compactness of the silicon dioxide film is effectively improved, the purpose of preventing the silicon dioxide film from absorbing moisture is achieved, the stress stability is maintained, and therefore the good technical effects that the annealing treatment step is omitted, and the production cost is reduced are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor materials, and in particular relates to a thin film preparation process for improving silicon dioxide stress stability without annealing, a silicon dioxide thin film product and an application. Background Art

[0002] Sub-atmospheric chemical vapor deposition (SACVD for short) is a chemical vapor deposition technology that is carried out at a sub-atmospheric pressure (pressure of 40 torr to 600 torr) environment through an ozone catalytic reaction at high temperature. With the continuous reduction in the size of semiconductor devices, whether the manufacturing process has a good filling ability for holes with a large aspect ratio has become a key indicator for the selection of thin film material types and their deposition technology. Among them, SACVD has been widely used in the front-end processes of semiconductor manufacturing (such as trench filling and interlayer dielectric layer deposition) because of its excellent step coverage and hole filling capabilities, as well as the advantage of no plasma damage to the substrate. For example, shallow trench filling in shallow trench isolation structures and the formation of interlayer dielectric layers.

[0003] At present, most of the materials deposited using the SACVD deposition method are silicon dioxide (SAUSG for short), but there are two problems in its practical application: On the one hand, the silicon dioxide generated by the liquid source reaction is usually deposited at a relatively low temperature using a liquid precursor (such as TEOS, tetraethyl orthosilicate). Due to the low reaction temperature, the generated silicon dioxide structure may not be dense enough, and there are more pores or defects, resulting in the corresponding structural density being poorer than the density of silicon dioxide generated by the gas source reaction. On the other hand, as time goes by, the deposited silicon dioxide film will continue to absorb moisture and release stress. This stress release will cause the stability of the silicon dioxide film to decrease, especially after being placed for a period of time, the stress will gradually decrease, thereby affecting the mechanical properties of the silicon dioxide film. In order to solve the above problems, researchers usually set up an additional annealing process to reorganize the structure of the silicon dioxide film to further improve the density and stability of the silicon dioxide film, but its cost is relatively high.

[0004] Therefore, in this field, there is an urgent need to develop a silicon dioxide film and a preparation method thereof, so as to comprehensively improve the density and stress stability of the film. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a thin film preparation process, a silicon dioxide thin film product and an application that improves the stress stability of silicon dioxide without annealing. The present invention uses a combination of helium and nitrogen to perform plasma treatment on the silicon dioxide film, thereby effectively improving the compactness of the silicon dioxide film, preventing the silicon dioxide film from absorbing moisture, and maintaining stress stability, thereby achieving the good technical effect of eliminating the annealing step and reducing production costs.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a thin film preparation process for improving the stress stability of silicon dioxide without annealing, the thin film preparation process comprising the following steps:

[0008] Providing a substrate, and forming a silicon dioxide film layer on the substrate by a chemical vapor deposition method;

[0009] The surface of the silicon dioxide film layer is subjected to plasma treatment, wherein the plasma in the plasma treatment is a combination of plasma helium and plasma nitrogen, to obtain the silicon dioxide thin film product.

[0010] The present invention uses a combination of helium and nitrogen to perform plasma treatment on the surface of a silicon dioxide film layer, thereby significantly improving the compactness, moisture resistance and stress stability of the silicon dioxide film.

[0011] On the one hand, the present invention uses helium inert gas plasma with good bombardment effect to bombard the above silicon dioxide film, bombarding the loosely bonded groups, adsorbed molecules and hydrogen atoms on the film and repairing the dangling bonds of the film through the heat energy provided by the heating stage and the plasma energy provided by the helium inert gas, thereby enhancing the compactness of the silicon dioxide film. On the other hand, the present invention uses nitrogen plasma treatment to introduce nitrogen elements on the surface of the silicon dioxide film, thereby forming silicon nitride (Si 3 N 4 ) or nitrogen-doped silicon dioxide (SiON) isolation layer is used to isolate the air, thereby further improving the moisture resistance and stress stability of the silicon dioxide film, and ultimately effectively improving the problem of stress reduction of the silicon dioxide film over time.

[0012] In addition, the silicon dioxide film preparation process provided by the present invention can eliminate the annealing step, thereby saving process flow and reducing production costs.

[0013] Preferably, performing plasma treatment on the surface of the silicon dioxide film layer comprises:

[0014] A mixed gas consisting of helium and nitrogen is introduced into the reaction chamber where the silicon dioxide film layer is located, the mixed gas is ionized to obtain plasma, and the surface of the silicon dioxide film layer is plasma treated with the plasma.

[0015] Preferably, the flow rate of helium is 900sccm-1100sccm, preferably 950sccm-1050sccm, for example, it can be 900sccm, 920sccm, 950sccm, 980sccm, 1000sccm, 1020sccm, 1050sccm, 1080sccm, 1100sccm, etc., not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, the flow rate of the nitrogen gas is 400sccm-600sccm, preferably 450sccm-550sccm, for example, it can be 400sccm, 420sccm, 450sccm, 480sccm, 500sccm, 520sccm, 550sccm, 580sccm, 600sccm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the flow rate ratio of the helium gas to the nitrogen gas is (1.5-2.5):1, more preferably 2:1, for example, it can be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, etc., not limited to the listed values, other values ​​not listed in the numerical range are also applicable. The present invention can reduce impurities and defects in the silicon dioxide film and adjust its stress distribution by regulating the flow rate ratio of the helium gas to the nitrogen gas.

[0018] If helium with a large flow rate or nitrogen with a large flow rate is used, it will cause uneven gas mixing and large local temperature or concentration gradient of the gas, resulting in uneven stress distribution inside the silicon dioxide film, and the stress cannot be maintained stable. In addition, high-speed airflow may disturb the reaction zone, destroy the film-forming conditions, and cause the silicon dioxide film structure to be loose or have hole defects. If helium with a small flow rate or nitrogen with a small flow rate is used, it will cause uneven gas mixing, resulting in uneven distribution of silicon dioxide film composition, thickness and temperature, causing local stress concentration or cracks, and low flow rate will cause by-products to be unable to be discharged in time, which is easy to cause side reactions, thereby increasing the impurity content in the silicon dioxide film.

[0019] If the flow rates of helium and nitrogen are relatively large, that is, when the proportion of helium is high, the high thermal conductivity of helium will increase heat dissipation, resulting in abnormal stress of the silicon dioxide film; if the flow rates of helium and nitrogen are relatively small, that is, when the proportion of nitrogen is high, it is easy to cause local temperature rise, which will lead to thermal stress concentration. Therefore, the flow ratio range of helium and nitrogen needs to be adapted according to the characteristics of the silicon dioxide film and combined with pressure, temperature and other conditions.

[0020] Preferably, the pressure of the reaction chamber is 1.2torr-1.8torr, preferably 1.4torr-1.6torr, for example, it can be 1.2torr, 1.3torr, 1.4torr, 1.45torr, 1.5torr, 1.55torr, 1.6torr, 1.7torr, 1.8torr, etc., not limited to the numerical values ​​listed, other numerical values ​​not listed in the numerical range are also applicable. The present invention, by regulating the pressure of the reaction chamber, makes it possible not only to improve the plasma treatment efficiency and stability, but also optimize the surface properties of the silicon dioxide film, reduce defects, and improve product quality. If the pressure of the reaction chamber is small, the compactness of the silicon dioxide thin film may be changed, causing stress anomalies, and the difference in gas coverage between the edge and the center may be increased, resulting in edge effect or uneven thickness. If the pressure of the reaction chamber is large, it will be unfavorable for maintaining the stress stability of the silicon dioxide film product.

[0021] Preferably, the power of the HF generator used to ionize the mixed gas is 1000W-1200W, preferably 1050W-1150W, for example, it can be 1000W, 1020W, 1050W, 1080W, 1100W, 1120W, 1150W, 1180W, 1200W, etc., not limited to the listed values, other unlisted values ​​within the numerical range are also applicable. The present invention can optimize the distribution and activity of plasma by regulating the power of the HF generator. If the power of the HF generator is small, the generated plasma content will be small. If the power of the HF generator is large, the silicon dioxide film may be damaged.

[0022] Preferably, the plate spacing during the plasma treatment process is 400mils-500mils, preferably 430mil-470mil, for example, 400mils, 420mils, 430mils, 450mils, 470mils, 480mils, 500mils, not limited to the listed values, other unlisted values ​​within the numerical range are also applicable. The present invention can better optimize the temperature and energy distribution of the plasma by regulating the setting range of the plate spacing, thereby improving the plasma treatment effect. If a smaller plate spacing is used, the silicon dioxide film may be damaged. If a larger plate spacing is used, it will be detrimental to uniform plasma treatment.

[0023] In the present invention, the plate spacing refers to the distance between the substrate and the gas distribution disk.

[0024] Preferably, the temperature of the plasma is 350°C-480°C, preferably 370°C-420°C, for example, it can be 350°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 450°C, 480°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the time for plasma treatment of the surface of the silicon dioxide film layer is 40s-80s, for example, it can be 40s, 42s, 45s, 48s, 50s, 52s, 55s, 58s, 60s, 62s, 65s, 68s, 70s, 72s, 75s, 78s, 80s, etc.

[0026] In the present invention, the plasma treatment equipment exemplarily includes plasma enhanced chemical vapor deposition equipment (abbreviated as PECVD).

[0027] Preferably, the chemical vapor deposition method includes sub-atmospheric pressure chemical vapor deposition (SACVD for short).

[0028] Preferably, the sub-atmospheric pressure chemical vapor deposition process comprises reacting a silicon liquid source precursor with ozone, and finally depositing a silicon dioxide film layer on the substrate.

[0029] Preferably, the working conditions of the sub-atmospheric pressure chemical vapor deposition are: the temperature of the heater is 300° C.-500° C., and the deposition pressure is 60 torr-500 torr.

[0030] Specifically, the temperature of the heater can be 300°C, 320°C, 350°C, 380°C, 400°C, 420°C, 450°C, 480°C, 500°C, etc., and is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable; the deposition pressure can be 60torr, 80torr, 100torr, 200torr, 300torr, 400torr, 500torr, etc., and is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable.

[0031] In the present invention, the substrate exemplarily includes a wafer.

[0032] In the present invention, the silicon liquid source precursor exemplarily includes tetraethyl orthosilicate (TEOS).

[0033] As a preferred technical solution of the present invention, the method comprises the following steps:

[0034] S1. Providing a substrate, and setting the temperature of the heater in the sub-atmospheric pressure chemical vapor deposition apparatus to 300°C-500°C, and placing the substrate on the heater;

[0035] S2. The silicon liquid source precursor is introduced into the reaction chamber;

[0036] S3. Performing sub-atmospheric pressure chemical vapor deposition in an ozone environment to form a silicon dioxide film layer, wherein the pressure of the sub-atmospheric pressure chemical vapor deposition is 60torr-500torr;

[0037] S4. After the deposition, He / O 2 Into the reaction chamber for purging;

[0038] S5. After the purge is completed, the residual gas in the reaction chamber is extracted to restore the reaction chamber to a vacuum state;

[0039] S6. A mixed gas consisting of helium at a flow rate of 900 sccm-1100 sccm and nitrogen at a flow rate of 400 sccm-600 sccm is introduced into the reaction chamber to reach a pressure of 1.2 torr-1.8 torr in the reaction chamber, wherein the flow rate ratio of helium to nitrogen is (1.5-2.5): 1;

[0040] S7. The mixed gas is ionized to obtain a plasma, and the surface of the silicon dioxide film layer is subjected to a plasma treatment for 40s-80s at a temperature of 350°C-480°C, wherein the power of the HF generator for ionizing the mixed gas is 1000W-1200W, and the plate spacing is 400mils-500mils;

[0041] S8. After the plasma treatment is completed, the residual gas in the reaction chamber is extracted to restore the reaction chamber to a vacuum state, and the silicon dioxide thin film product is taken out.

[0042] In a second aspect, the present invention provides a silicon dioxide thin film product, wherein the silicon dioxide thin film product is produced by the thin film preparation process for improving silicon dioxide stress stability by annealing-free according to the first aspect.

[0043] The silicon dioxide thin film product provided by the present invention can reduce damage during high-temperature annealing and improve the production efficiency of the product.

[0044] In a third aspect, the present invention provides an application of the silicon dioxide thin film product according to the second aspect, wherein the silicon dioxide thin film product is applied to the production of semiconductor materials.

[0045] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present invention provides a thin film preparation process for improving the stress stability of silicon dioxide without annealing. The present invention performs plasma treatment on the surface of the silicon dioxide film layer by utilizing a combination of helium and nitrogen, thereby significantly improving the compactness, moisture resistance and stress stability of the silicon dioxide film.

[0048] On the one hand, the present invention uses helium inert gas plasma with good bombardment effect to bombard the above silicon dioxide film, bombarding the loosely bonded groups, adsorbed molecules and hydrogen atoms on the film and repairing the dangling bonds of the film through the heat energy provided by the heating stage and the plasma energy provided by the helium inert gas, thereby enhancing the compactness of the silicon dioxide film. On the other hand, the present invention uses nitrogen plasma treatment to introduce nitrogen elements on the surface of the silicon dioxide film, thereby forming silicon nitride (Si 3 N 4 ) or nitrogen-doped silicon dioxide (SiON) isolation layer is used to isolate the air, thereby further improving the moisture resistance and stress stability of the silicon dioxide film, and ultimately effectively improving the problem of stress reduction of the silicon dioxide film over time.

[0049] In addition, the silicon dioxide film preparation process provided by the present invention can eliminate the annealing step, and the machine is compatible with SACVD and PECVD processes, and does not need to add redundant steps, thereby saving process flow and reducing production costs. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0051] The equipment for plasma treatment in the embodiments and comparative examples of the present invention is a plasma enhanced chemical vapor deposition (PECVD) equipment, wherein the radio frequency system used is AENI, and the frequency is 13.56 MHZ.

[0052] Example 1

[0053] This embodiment provides a silicon dioxide thin film product and a preparation process thereof, wherein the preparation process comprises the following steps:

[0054] S1. Provide a wafer, set the temperature of the heater in the sub-atmospheric pressure chemical vapor deposition (SACVD) device to 400°C, and place the wafer on the heater;

[0055] S2. The ethyl orthosilicate liquid source precursor is introduced into the reaction chamber, wherein the flow rate of the ethyl orthosilicate liquid source precursor introduced into the chamber is controlled to be 280 sccm;

[0056] S3. The ozone is introduced into the reaction chamber, and sub-atmospheric pressure chemical vapor deposition is performed in an ozone environment to form a silicon dioxide film layer (SAUSG), wherein the pressure of the sub-atmospheric pressure chemical vapor deposition is 280torr;

[0057] S4. After the deposition, He / O 2 Into the reaction chamber for purging;

[0058] S5. After the purge is completed, the residual gas in the reaction chamber is extracted through the exhaust device to restore the reaction chamber to a vacuum state;

[0059] S6. A mixed gas consisting of helium at a flow rate of 1000 sccm and nitrogen at a flow rate of 500 sccm is introduced into the reaction chamber to reach a pressure of 1.5 torr in the reaction chamber, wherein the flow rate ratio of helium to nitrogen is 2:1;

[0060] S7. The mixed gas is ionized to obtain plasma, and the surface of the silicon dioxide film layer is subjected to plasma treatment for 60 seconds using a plasma at a temperature of 400° C., wherein the power of the HF generator for ionizing the mixed gas is 1100 W, and the plate spacing is 450 mils;

[0061] S8. After the plasma treatment is completed, the residual gas in the reaction chamber is extracted through the exhaust device to restore the reaction chamber to a vacuum state, and the silicon dioxide thin film product is taken out.

[0062] Example 2

[0063] This embodiment provides a silicon dioxide thin film product and a preparation process thereof, wherein the preparation process comprises the following steps:

[0064] S1. Provide a wafer, set the temperature of the heater in the sub-atmospheric pressure chemical vapor deposition equipment to 400°C, and place the wafer on the heater;

[0065] S2. The ethyl orthosilicate liquid source precursor is introduced into the reaction chamber, wherein the flow rate of the ethyl orthosilicate liquid source precursor introduced into the chamber is controlled to be 280 sccm;

[0066] S3. The ozone is introduced into the reaction chamber, and sub-atmospheric pressure chemical vapor deposition is performed in an ozone environment to form a silicon dioxide film layer, wherein the pressure of the sub-atmospheric pressure chemical vapor deposition is 300torr;

[0067] S4. After the deposition, He / O 2 Into the reaction chamber for purging;

[0068] S5. After the purge is completed, the residual gas in the reaction chamber is extracted through the exhaust device to restore the reaction chamber to a vacuum state;

[0069] S6. A mixed gas consisting of helium at a flow rate of 950 sccm and nitrogen at a flow rate of 450 sccm is introduced into the reaction chamber to reach a pressure of 1.4 torr in the reaction chamber, wherein the flow rate ratio of helium to nitrogen is 2:1;

[0070] S7. The mixed gas is ionized to obtain plasma, and the surface of the silicon dioxide film layer is plasma treated for 60 seconds using a plasma at a temperature of 400° C., wherein the power of the HF generator for ionizing the mixed gas is 1050 W, and the plate spacing is 430 mils;

[0071] S8. After the plasma treatment is completed, the residual gas in the reaction chamber is extracted through the exhaust device to restore the reaction chamber to a vacuum state, and the silicon dioxide thin film product is taken out.

[0072] Example 3

[0073] This embodiment provides a silicon dioxide thin film product and a preparation process thereof, wherein the preparation process comprises the following steps:

[0074] S1. Provide a wafer, set the temperature of the heater in the sub-atmospheric pressure chemical vapor deposition equipment to 400°C, and place the wafer on the heater;

[0075] S2. The ethyl orthosilicate liquid source precursor is introduced into the reaction chamber, wherein the flow rate of the ethyl orthosilicate liquid source precursor introduced into the chamber is controlled to be 280 sccm;

[0076] S3. The ozone is introduced into the reaction chamber, and sub-atmospheric pressure chemical vapor deposition is performed in an ozone environment to form a silicon dioxide film layer, wherein the pressure of the sub-atmospheric pressure chemical vapor deposition is 300torr;

[0077] S4. After the deposition, He / O 2 Into the reaction chamber for purging;

[0078] S5. After the purge is completed, the residual gas in the reaction chamber is extracted through the exhaust device to restore the reaction chamber to a vacuum state;

[0079] S6. A mixed gas consisting of helium at a flow rate of 1050 sccm and nitrogen at a flow rate of 550 sccm is introduced into the reaction chamber to reach a pressure of 1.6 torr in the reaction chamber, wherein the flow rate ratio of helium to nitrogen is 2:1;

[0080] S7. The mixed gas is ionized to obtain plasma, and the surface of the silicon dioxide film layer is subjected to plasma treatment for 60 seconds using a plasma at a temperature of 400° C., wherein the power of the HF generator for ionizing the mixed gas is 1150 W, and the plate spacing is 470 mils;

[0081] S8. After the plasma treatment is completed, the residual gas in the reaction chamber is extracted through the exhaust device to restore the reaction chamber to a vacuum state, and the silicon dioxide thin film product is taken out.

[0082] Example 4

[0083] The difference between this embodiment and embodiment 1 is that the flow rate ratio of helium gas to nitrogen gas in step S6 is 1:1, and the rest is the same as embodiment 1.

[0084] Example 5

[0085] The difference between this embodiment and embodiment 1 is that the flow rate ratio of helium gas to nitrogen gas in step S6 is 5:1, and the rest is the same as embodiment 1.

[0086] Example 6

[0087] The difference between this embodiment and embodiment 1 is that the pressure of the reaction chamber in step S6 is 0.6 torr, and the rest is the same as embodiment 1.

[0088] Example 7

[0089] The difference between this embodiment and embodiment 1 is that the pressure of the reaction chamber in step S6 is 2.5 torr, and the rest is the same as embodiment 1.

[0090] Example 8

[0091] The difference between this embodiment and the first embodiment is that the power of the HF generator for ionizing the mixed gas in step S7 is 700 W, and the rest is the same as the first embodiment.

[0092] Example 9

[0093] The difference between this embodiment and the first embodiment is that the power of the HF generator for ionizing the mixed gas in step S7 is 1500 W, and the rest is the same as the first embodiment.

[0094] Example 10

[0095] The difference between this embodiment and embodiment 1 is that the plate spacing in step S7 is 300 mils, and the rest is the same as embodiment 1.

[0096] Embodiment 11

[0097] The difference between this embodiment and embodiment 1 is that the plate spacing in step S7 is 800 mils, and the rest is the same as embodiment 1.

[0098] Comparative Example 1

[0099] The difference between this comparative example and Example 1 is that in step S6, no nitrogen is introduced, and only helium with a flow rate of 1000 sccm is introduced. The rest is the same as Example 1.

[0100] Comparative Example 2

[0101] The difference between this comparative example and Example 1 is that in step S6, helium is not introduced, and a mixed gas consisting of argon with a flow rate of 1000 sccm and nitrogen with a flow rate of 500 sccm is introduced. The rest is the same as Example 1.

[0102] Comparative Example 3

[0103] The difference between this comparative example and Example 1 is that in step S6, no helium gas is introduced, and only nitrogen gas with a flow rate of 500 sccm is introduced. The rest is the same as Example 1.

[0104] Comparative Example 4

[0105] This comparative example provides a silicon dioxide film layer prepared by a sub-atmospheric pressure chemical vapor deposition method. The specific sub-atmospheric pressure chemical vapor deposition steps and their parameters are the same as steps S1 to S5 in Example 1.

[0106] Test conditions

[0107] The silicon dioxide thin film products provided in Examples 1 to 11 and Comparative Examples 1 to 4 were subjected to performance tests, and the test conditions are as follows:

[0108] A 6-inch wafer was selected, and the corresponding stress value was tested by a stress meter before plasma treatment. The corresponding stress value was tested by the stress meter after intervals of 5 minutes, 30 minutes and 60 minutes after plasma treatment.

[0109] The test results are shown in Table 1:

[0110] Table 1

[0111]

[0112]

[0113] As can be seen from Table 1, by comparing Examples 1 to 3 with Comparative Example 4, the present invention significantly improves the density, moisture resistance and stress stability of the silicon dioxide film by plasma treating the surface of the silicon dioxide film layer using a combination of helium and nitrogen.

[0114] By comparing Example 1 with Example 4-Example 5, it can be seen that the flow rate ratio of helium to nitrogen can affect the effect of plasma treatment. The present invention achieves the technical effect of maintaining uniform heat distribution inside the reaction chamber and uniform thermal stress distribution of the silicon dioxide film by adjusting the flow rate ratio of helium to nitrogen to (1.5-2.5):1.

[0115] By comparing Example 1 with Example 6-Example 7, it can be seen that the pressure of the reaction chamber can affect the effect of plasma treatment. The present invention achieves the technical effect of uniform gas distribution inside the reaction chamber and is beneficial to improving the density and stress stability of the silicon dioxide film by adjusting the pressure of the reaction chamber to 1.2torr-1.8torr.

[0116] By comparing Example 1 with Example 8-Example 9, it can be seen that the power of the HF generator that ionizes the mixed gas can affect the effect of plasma treatment. The present invention achieves the technical effect of optimizing the distribution and activity of plasma by regulating the power of the HF generator that ionizes the mixed gas to 1000W-1200W.

[0117] By comparing Example 1 with Example 10-Example 11, it can be seen that the electrode plate spacing can affect the effect of plasma treatment. The present invention adjusts the electrode plate spacing to 400 mils-500 mils, thereby achieving better optimization of plasma temperature and energy distribution, thereby improving the purpose of plasma treatment effect.

[0118] From the comparison between Example 1 and Comparative Examples 1 to 3, it can be seen that the present invention, by setting a combination of helium and nitrogen and further optimizing the flow ratio between the two, achieves the technical effect of ensuring that the silicon dioxide film has good density and moisture resistance while also having a certain stress stability, without the need for additional annealing treatment.

[0119] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A thin film preparation process for improving the stress stability of silicon dioxide without annealing, characterized in that: The film preparation process comprises the following steps: Providing a substrate, and forming a silicon dioxide film layer on the substrate by a chemical vapor deposition method; The surface of the silicon dioxide film layer is subjected to plasma treatment, wherein the plasma in the plasma treatment is a combination of plasma helium and plasma nitrogen, to obtain the silicon dioxide thin film product.

2. The thin film preparation process according to claim 1, characterized in that: Plasma treatment of the surface of the silicon dioxide film layer includes: A mixed gas consisting of helium and nitrogen is introduced into the reaction chamber where the silicon dioxide film layer is located, the mixed gas is ionized to obtain plasma, and the surface of the silicon dioxide film layer is plasma treated with the plasma.

3. The thin film preparation process according to claim 2, characterized in that: The flow rate of the helium gas is 900 sccm-1100 sccm, preferably 950 sccm-1050 sccm; Preferably, the flow rate of the nitrogen gas is 400sccm-600sccm, preferably 450sccm-550sccm; Preferably, the flow ratio of the helium gas to the nitrogen gas is (1.5-2.5):1, and more preferably 2:

1.

4. The thin film preparation process according to claim 2 or 3, characterized in that: The pressure of the reaction chamber is 1.2 torr-1.8 torr, preferably 1.4 torr-1.6 torr.

5. The thin film preparation process according to claim 2, characterized in that: The power of the HF generator used to ionize the mixed gas is 1000W-1200W, preferably 1050W-1150W; Preferably, the plate spacing during the plasma treatment process is 400 mils-500 mils, preferably 430 mil-470 mil; Preferably, the temperature of the plasma is 350°C-480°C, preferably 370°C-420°C; Preferably, the time for plasma treatment on the surface of the silicon dioxide film layer is 40s-80s.

6. The thin film preparation process according to any one of claims 1 to 5, characterized in that: The chemical vapor deposition method includes sub-atmospheric pressure chemical vapor deposition; Preferably, the sub-atmospheric pressure chemical vapor deposition process comprises reacting a silicon liquid source precursor with ozone, and finally depositing a silicon dioxide film layer on the substrate.

7. The thin film preparation process according to claim 6, characterized in that: The working conditions of the sub-atmospheric pressure chemical vapor deposition are: the temperature of the heater is 300° C.-500° C., and the deposition pressure is 60 torr-500 torr.

8. The thin film preparation process according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: S1. Providing a substrate, and setting the temperature of the heater in the sub-atmospheric pressure chemical vapor deposition apparatus to 300°C-500°C, and placing the substrate on the heater; S2. The silicon liquid source precursor is introduced into the reaction chamber; S3. Performing sub-atmospheric pressure chemical vapor deposition in an ozone environment to form a silicon dioxide film layer, wherein the pressure of the sub-atmospheric pressure chemical vapor deposition is 60torr-500torr; S4. After the deposition is completed, He / O2 is introduced into the reaction chamber for purging; S5. After the purge is completed, the residual gas in the reaction chamber is extracted to restore the reaction chamber to a vacuum state; S6. A mixed gas consisting of helium at a flow rate of 900 sccm-1100 sccm and nitrogen at a flow rate of 400 sccm-600 sccm is introduced into the reaction chamber to reach a pressure of 1.2 torr-1.8 torr in the reaction chamber, wherein the flow rate ratio of helium to nitrogen is (1.5-2.5): 1; S7. The mixed gas is ionized to obtain a plasma, and the surface of the silicon dioxide film layer is subjected to a plasma treatment for 40s-80s at a temperature of 350°C-480°C, wherein the power of the HF generator for ionizing the mixed gas is 1000W-1200W, and the plate spacing is 400mils-500mils; S8. After the plasma treatment is completed, the residual gas in the reaction chamber is extracted to restore the reaction chamber to a vacuum state, and the silicon dioxide thin film product is taken out.

9. A silicon dioxide thin film product, characterized in that: The silicon dioxide thin film product is prepared by the thin film preparation process for improving silicon dioxide stress stability without annealing according to any one of claims 1-8.

10. An application of the silicon dioxide thin film product according to claim 9, characterized in that: The silicon dioxide thin film product is used in the production of semiconductor materials.

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