Method for improving uniformity of etching interval of silicon nitride film

Abstract

The invention provides a method for improving the uniformity of a silicon nitride film etching interval, and the method comprises the steps: providing a reaction cavity for depositing a silicon nitride film, enabling the bottom of the reaction cavity to be provided with an air inlet, enabling the top of the reaction cavity to be provided with an air outlet, and enabling a wafer boat to be placed in the reaction cavity; an injection device is arranged on one side in the reaction cavity and used for injecting reaction gas, one end of the injection device enters from the gas inlet and extends to be at least flush with the top of the wafer boat, and the other end of the injection device is arranged at the gas inlet; wherein the reaction cavity is divided into a bottom section, a middle section and a top section from bottom to top, and the injection device is provided with gas outlet parts in the three sections. According to the invention, the problem of interval difference of dry and wet etching rates caused by interval difference of the existing silicon nitride film on the whole wafer boat is solved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and particularly to a method for improving the uniformity of the etching interval of a silicon nitride thin film. Background Art

[0002] In the existing HCD silicon nitride deposition process machine, a susceptor is used to load substrates into the reaction chamber for operation. The reaction chamber in the prior art is a vertical cylindrical structure, such as a furnace tube. Inside the furnace tube, multiple substrates are arranged in sequence from bottom to top. The gas input pipe extends from the bottom of the reaction chamber into the reaction chamber and is located on one side of the substrates, so that the reaction gas is introduced into the reaction chamber to form a film on the surface of the substrates.

[0003] Currently, the film formation method in the HCD process is film formation by the conventional chemical vapor deposition method. The reaction gas for film formation is introduced from the bottom of the reaction chamber and then extracted from the top of the reaction chamber. Due to the special structure of the machine, during the diffusion process of the reaction gas from bottom to top in the chamber, the concentration will gradually decrease. While ensuring the uniformity of the film formation thickness, the temperature of the reaction chamber will be higher towards the top. In this case, there will be regional differences in the film quality on the entire susceptor, and this difference will be manifested as regional differences in the dry and wet etching rates. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a method for improving the uniformity of the etching interval of a silicon nitride thin film, which is used to solve the problem that there are regional differences in the existing silicon nitride film quality on the entire susceptor, resulting in regional differences in the dry and wet etching rates.

[0005] To achieve the above purpose and other related purposes, the present invention provides a method for improving the uniformity of the etching interval of a silicon nitride thin film, and the method includes:

[0006] Providing a reaction chamber for depositing a silicon nitride thin film, the bottom of the reaction chamber is provided with an air inlet, the top of the reaction chamber is provided with an air outlet, and a susceptor is placed in the reaction chamber;

[0007] Providing an injection device on one side of the reaction chamber for injecting reaction gas, one end of the injection device enters from the air inlet and extends to at least the same level as the top of the susceptor, and the other end is placed at the air inlet;

[0008] Wherein, the reaction chamber is divided into a bottom interval, a middle interval, and a top interval from bottom to top, and the injection device is provided with air outlet parts in all three intervals.

[0009] Optionally, the injection device includes an inlet pipe.

[0010] Optionally, the material of the inlet pipe includes quartz.

[0011] Optionally, at least one gas outlet is provided in each interval.

[0012] Optionally, the gas outlet includes a gas outlet hole.

[0013] Optionally, the gas outlet holes located in different intervals have exactly the same shape and size.

[0014] Optionally, when each interval includes a plurality of gas outlet holes, the number of the gas outlet holes in each interval is the same.

[0015] Optionally, the shapes and sizes of the plurality of gas outlet holes in a single interval can be different.

[0016] Optionally, the number of the gas outlet holes with the same shape and the same size in each interval is the same.

[0017] As described above, the method for improving the etching interval uniformity of the silicon nitride thin film according to the present invention ensures that the reaction gases in different intervals of the entire reaction chamber have the same reaction concentration, reduces the temperature difference at different positions of the reaction chamber body, improves the etching rate difference of the silicon nitride films formed at different positions of the susceptor, and expands the process window of the subsequent process by extending the length of the injection device to the top of the susceptor and providing gas outlet holes at different positions to increase their number. Brief Description of the Drawings

[0018] Figure 1 It is shown as a flowchart of the method for improving the etching interval uniformity of the silicon nitride thin film according to the present invention.

[0019] Figure 2 It is shown as a schematic diagram of the setting mode of the injection device according to the present invention. Detailed Embodiment

[0020] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0021] Please refer to Figures 1 to 2 ... It should be noted that the drawings provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Although only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape, and size of the components in actual implementation, the actual shape, number, and proportion of each component during actual implementation can be arbitrarily changed, and the component layout form may also be more complex.

[0022] Such as Figure 1As shown in the figure, this embodiment provides a method for improving the uniformity of the etching interval of a silicon nitride thin film. The method includes:

[0023] Providing a reaction chamber for depositing a silicon nitride thin film. An air inlet is provided at the bottom of the reaction chamber, an air outlet is provided at the top thereof, and a susceptor is placed in the reaction chamber.

[0024] Providing an injection device on one side of the reaction chamber for injecting reaction gas. One end of the injection device enters from the air inlet and extends to at least the same level as the top of the susceptor, and the other end is placed at the air inlet.

[0025] Wherein, the reaction chamber is divided into a bottom interval, a middle interval and a top interval from bottom to top, and the injection device is provided with air outlet parts in all three intervals.

[0026] Specifically, the injection device includes an inlet pipe.

[0027] More specifically, the material of the inlet pipe includes quartz.

[0028] Specifically, each interval is provided with at least one air outlet part.

[0029] More specifically, the air outlet part includes an air outlet hole.

[0030] As an example, the shapes and sizes of the air outlet holes located in different intervals are exactly the same.

[0031] As an example, when each interval includes a plurality of air outlet holes, the number of the air outlet holes in each interval is the same.

[0032] Furthermore, the shapes and sizes of the plurality of air outlet holes in a single interval can be different.

[0033] Furthermore, the number of the air outlet holes with the same shape and the same size in each interval is the same.

[0034] In this embodiment, it should be noted that Figure 2 the shown inlet pipe is actually located in the reaction chamber. For the convenience of clearly showing each part and for easy drawing, it is shown outside the reaction chamber.

[0035] In summary, for the method for improving the uniformity of the etching interval of the silicon nitride thin film according to the present invention, by extending the length of the injection device to the top of the susceptor and setting air outlet holes at different positions to increase the number thereof, the reaction gas in different intervals of the entire reaction chamber can be ensured to have the same reaction concentration, the temperature difference at different positions of the reaction chamber body can be reduced, the etching rate difference of the silicon nitride film formed at different positions of the susceptor can be improved, and the process window of the subsequent process can be expanded. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0036] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for improving the uniformity of the etching interval of a silicon nitride thin film, characterized in that, The method includes: providing a reaction chamber for depositing a silicon nitride thin film, the bottom of the reaction chamber being provided with an air inlet, the top thereof being provided with an air outlet, and a susceptor being placed in the reaction chamber; arranging an injection device on one side in the reaction chamber for injecting reaction gas, one end of the injection device entering from the air inlet and extending to at least the same level as the top of the susceptor, and the other end being placed at the air inlet; wherein the reaction chamber is divided into a bottom section, a middle section and a top section from bottom to top, and the injection device is provided with air outlet parts in all three sections.

2. The method for improving the etching interval uniformity of the silicon nitride thin film according to claim 1, wherein The injection device includes an inlet pipe.

3. The method for improving the etching interval uniformity of the silicon nitride thin film according to claim 2, characterized in that, The material of the inlet pipe includes quartz.

4. The method for improving the etching interval uniformity of the silicon nitride film according to claim 1, wherein Each section is provided with at least one air outlet part.

5. The method for improving the etching interval uniformity of the silicon nitride thin film according to claim 4, wherein The air outlet part includes an air outlet hole.

6. The method for improving the etching interval uniformity of a silicon nitride thin film according to claim 5, characterized in that, The shapes and sizes of the air outlet holes in different sections are exactly the same.

7. The method for improving the etching interval uniformity of the silicon nitride thin film according to claim 5, characterized in that, When each section includes a plurality of air outlet holes, the number of the air outlet holes in each section is the same.

8. The method for improving the etching interval uniformity of the silicon nitride thin film according to claim 7, wherein, The shapes and sizes of the plurality of air outlet holes in a single section can be different.

9. The method for improving the etching interval uniformity of the silicon nitride thin film according to claim 7, wherein The number of the air outlet holes with the same shape and the same size in each section is the same.

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