A cleaning system for silicon nitride etch masks

Abstract

The application relates to a cleaning system for a silicon nitride etching leak plate, which comprises a first body, a second body rotationally connected with the first body, a cleaning pipeline composed of a main pipeline arranged in the first body and a blowing pipeline arranged in the second body, a plasma generator connected with the main pipeline and a recovery channel penetrating through the first body and the second body, the axis of the recovery channel coincides with the axis of the main pipeline, and the plurality of blowing pipelines around the axis of the recovery channel are uniformly arranged in the main pipeline, the first end of the blowing pipeline is communicated with the main pipeline, and the second end of the blowing pipeline is inclined to the direction close to the recovery channel. The cleaning system for the silicon nitride etching leak plate disclosed by the application can realize complete removal of photoresist on a complex pattern through targeted cleaning of the area on the substrate, and can realize cleaning parameter adjustment of each area through movement and air flow pressure adjustment, so that structure damage caused by long-time exposure of the substrate is avoided.

Description

Technical Field

[0001] This application relates to the field of chip manufacturing equipment technology, and in particular to a cleaning system for a silicon nitride etching stencil. Background Technology

[0002] In the process of etching silicon nitride stencils, photoresist is needed to assist in production, and then the photoresist is stripped off after production. There are two etching methods: dry etching and wet etching. Wet etching relies on the corrosiveness of the solution, but this method is anisotropic and requires a large amount of water and cleaning solvents. It is gradually being replaced by dry etching.

[0003] Dry etching uses light to complete the etching process and is isotropic. Based on dry etching, the photoresist removal process enters the dry removal stage because dry removal is also isotropic, which can ensure the continuity of the isotropic properties of dry etching.

[0004] Currently, a mainstream dry etching method involves placing the substrate in a vacuum environment, injecting an appropriate amount of oxygen, and then ionizing it. The resulting plasma reacts with the photoresist under the drive of an electric field. This process places high demands on the vacuum level, electric field strength, and oxygen flow rate, and is also time-consuming.

[0005] One reason for the long processing time is the non-planar nature of the design pattern, which requires increasing the processing time to ensure complete removal of the photoresist. However, uneven distribution of the photoresist can lead to prolonged exposure of the substrate, posing a risk of damage. Summary of the Invention

[0006] This application provides a cleaning system for silicon nitride etching stencils, which achieves complete removal of photoresist on complex patterns by targeted cleaning of areas on the substrate. At the same time, the cleaning parameters of each area can be adjusted by moving and adjusting the airflow pressure, so as to avoid structural damage that may be caused by prolonged exposure of the substrate.

[0007] The above-mentioned objective of this application is achieved through the following technical solution:

[0008] This application provides a cleaning system for a silicon nitride etching stencil, comprising:

[0009] A first main body and a second main body rotatably connected to the first main body;

[0010] The cleaning pipeline includes a main pipeline located in the first main body and a purge pipeline located in the second main body. There are multiple purge pipelines, all of which are connected to the main pipeline.

[0011] The plasma generator is connected to the main pipeline;

[0012] The recycling channel runs through both the first and second main bodies;

[0013] The axis of the recycling channel coincides with the axis of the main pipeline, and the recycling channel is located inside the main pipeline.

[0014] Multiple purging pipes are evenly arranged around the axis of the recovery channel;

[0015] The first end of the purging pipe is connected to the main pipe, and the second end of the purging pipe is inclined towards the recovery channel.

[0016] In one possible implementation of this application, the area of ​​the area enclosed by the purge channel on the photoresist layer is one-half to two-thirds of the area of ​​the area enclosed by the purge channel.

[0017] In one possible implementation of this application, a windbreak curtain wall is provided on the second body, and the coverage area of ​​the purging pipe is located inside the coverage area of ​​the windbreak curtain wall;

[0018] The windshield curtain wall is tilted away from the recycling channel.

[0019] In one possible implementation of this application, the windbreak curtain wall extracts gas from the surrounding environment.

[0020] In one possible implementation of this application, the windbreak curtain wall includes:

[0021] Fan;

[0022] The air duct is located on the second main body;

[0023] The flexible pipe is connected to the fan and the air duct at both ends, respectively.

[0024] In one possible implementation of this application, the plasma generator uses an external gas to generate plasma.

[0025] In one possible implementation of this application, an arc-shaped guide is provided at the distal end of the second body, the recovery channel is located inside the arc-shaped guide, and the second end of the purging pipe is located outside the arc-shaped guide.

[0026] In one possible implementation of this application, the axis of the second end of the purge pipe is parallel to the tangent at the location of the arc-shaped guide body at the second end of the purge pipe.

[0027] In one possible implementation of this application, an arc-shaped guide ring is provided on the arc-shaped guide body;

[0028] The second end of the purging pipe is located between the arc-shaped guide body and the arc-shaped guide ring;

[0029] In the direction of gas flow, the distance between the outer wall of the arc-shaped guide body and the inner wall of the arc-shaped guide ring is equal everywhere. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of an existing photoresist removal method.

[0031] Figure 2 This is a structural schematic diagram of a cleaning system provided in this application.

[0032] Figure 3 This is a structural diagram of a first entity, a second entity, and their internal structures provided in this application.

[0033] Figure 4 This is a schematic diagram of the rotational connection between a first body and a second body provided in this application.

[0034] Figure 5 This is a schematic diagram of the flow path of a cleaning gas provided in this application.

[0035] Figure 6 This is a schematic diagram of a cleaning path on a substrate provided in this application.

[0036] Figure 7 This is a schematic diagram comparing existing photoresist removal methods.

[0037] Figure 8 This is a comparative schematic diagram of photoresist removal using the cleaning system provided in this application.

[0038] In the diagram, 2 is the cleaning pipe, 3 is the plasma generator, 4 is the recovery channel, 11 is the first main body, 12 is the second main body, 21 is the main pipe, 22 is the purging pipe, 23 is the arc-shaped guide body, 24 is the arc-shaped guide ring, 51 is the fan, 52 is the air duct, and 53 is the flexible pipe. Detailed Implementation

[0039] To better understand the technical solutions in this application, the relevant technologies will be introduced first.

[0040] Please see Figure 1 The substrate (the chip or intermediate that needs to be cleaned) in the diagram is placed inside a vacuum chamber, where it is ionized to generate plasma. An electric field is set inside the vacuum chamber, and the plasma flows from top to bottom. Figure 1 The arrow in the image moves, comes into contact with and reacts with the photoresist on the substrate, causing the photoresist to decompose.

[0041] In this method, the contact time between the substrate and the plasma is equal at all points, while in order to achieve photoresist on complex patterns ( Figure 2 For peeling (as shown), it is also necessary to increase the exposure time of the substrate.

[0042] The technical solutions in this application will be further described in detail below with reference to the accompanying drawings.

[0043] This application discloses a cleaning system for silicon nitride etching stencils. In some examples, the cleaning system for silicon nitride etching stencils disclosed in this application includes a first body 11, a second body 12, a cleaning pipe 2, a plasma generator 3, and a recovery channel 4.

[0044] First, it should be noted that please refer to [the relevant documentation / reference]. Figure 2 The silicon nitride etching stencil cleaning system disclosed in this application is installed inside a cleaning chamber. A rotating stage is arranged at the bottom of the cleaning chamber, and the substrate is placed on the rotating stage. The silicon nitride etching stencil cleaning system disclosed in this application is located on the top surface of the cleaning chamber.

[0045] Additionally, a linear lifting module and a horizontal moving module are required for movement. The linear lifting module is mounted on the top surface of the cleaning chamber, and the horizontal moving module is mounted on the linear lifting module. The linear lifting module and the horizontal moving module are used to realize the vertical lifting and horizontal translation of the silicon nitride etching stencil cleaning system disclosed in this application.

[0046] At this point, the rotation of the contact turntable can achieve full coverage of the substrate.

[0047] The first body 11 and the second body 12 are connected by a rotational connection, such as... Figure 4 As shown, the bearing is installed at the parting surface between the first body 11 and the second body 12.

[0048] In some possible implementations, a motor is mounted on the first body 11, which drives the second body 12 to rotate at a fixed speed.

[0049] The cleaning pipe 2 is divided into two parts: the main pipe 21 located in the first main body 11 and the purging pipe 22 located in the second main body 12. There are multiple purging pipes 22, all of which are connected to the main pipe 21. These purging pipes 22 are evenly arranged around the axis of the recycling channel 4.

[0050] pass Figure 4 As can be seen, there is a buffer area below the main pipe 21, and the purging pipe 22 is connected to the buffer area.

[0051] The plasma generator 3 is connected to the main pipe 21. The plasma generator 3 can be installed on the first main body 11 or on the top surface of the cleaning chamber.

[0052] When the plasma generator 3 is installed on the first main body 11, oxygen needs to be introduced from outside the cleaning chamber through a hose; when the plasma generator 3 is installed on the top surface of the cleaning chamber, oxygen is introduced from outside the cleaning chamber and connected to the main pipe 21 through a hose.

[0053] Plasma generator 3 uses external gas to generate plasma.

[0054] The recovery channel 4 runs through the first body 11 and the second body 12. Its function is to recover the gas that comes into contact with the substrate. The axis of the recovery channel 4 coincides with the axis of the main pipe 21 and the recovery channel 4 is located inside the main pipe 21. This allows the recovery channel 4 to be located at the center of the first body 11 and the second body 12.

[0055] In conjunction with a specific cleaning process, the linear lifting module and the horizontal moving module move the cleaning system for the silicon nitride etching stencil disclosed in this application to a cleaning position above the substrate, while simultaneously injecting inert gas into the cleaning chamber to create an inert gas environment.

[0056] Next, plasma generator 3 is started. The gas supplied to plasma generator 3 is oxygen. The ionized oxygen generates plasma, which is then sent into main pipe 21 and subsequently into each purge pipe 22. The plasma-containing oxygen (hereinafter referred to as cleaning gas) is ejected from the purge pipe 22 and comes into contact with the photoresist on the substrate, decomposing the photoresist. The flow path of the cleaning gas is as follows: Figure 5 As shown.

[0057] In the above process, the horizontal moving module and the rotating stage work together to remove photoresist from various parts of the substrate. One advantage of this method is its adaptability to substrates of different diameters, and it also allows for the concentration of cleaning gas, with a clear cleaning path for the substrate. Figure 6 As shown.

[0058] The cleaning gas ejected from the purge pipe 22, after contacting the substrate, exits the cleaning chamber through the recovery channel 4. The main byproduct of the cleaning gas's contact with the photoresist is gas; both the cleaning gas and the gas generated from the decomposition of the photoresist can exit the cleaning chamber through the recovery channel 4.

[0059] Comparison of cleaning effects Figure 7 and Figure 8 As shown, in Figure 7 It is quite evident that the photoresist removal in the vertical region is more difficult, but in Figure 8 This problem does not exist in China.

[0060] In addition, a certain amount of soluble substances are produced during the decomposition of photoresist. These soluble substances can be removed by adding water to the cleaning gas.

[0061] Regarding the shape of the purge pipe 22, its first end needs to be connected to the main pipe 21, and its second end needs to be inclined towards the recovery channel 4. The purpose is to ensure that the cleaning gas flows towards the recovery channel 4 and can quickly leave the cleaning chamber after contacting the substrate.

[0062] This is because the cleaning system provided in this application may generate photoresist debris compared to other cleaning methods. If these debris fall to other locations on the substrate, it will cause changes in the photoresist thickness at those locations, resulting in incomplete cleaning.

[0063] In some possible implementations, the area of ​​the enclosed region of the purge channel 22 on the photoresist layer is one-half to two-thirds of the area of ​​the enclosed region of the purge channel 22.

[0064] In some examples, the second body 12 is provided with a windbreak 5, and the coverage area of ​​the purge pipe 22 is located inside the coverage area of ​​the windbreak 5. The windbreak 5 is inclined away from the recovery channel 4. The function of the windbreak 5 is to form a barrier around the purge pipe 22 to prevent the generated photoresist debris from falling to other locations on the substrate.

[0065] Furthermore, the windshield curtain wall 5 extracts gas from the surrounding environment, that is, it directly uses inert gas from the surrounding environment.

[0066] In some examples, please refer to Figure 2 The windbreak curtain wall 5 includes a fan 51, an air duct 52 and a flexible pipe 53. The fan 51 can be installed on the top surface of the cleaning box, the air duct 52 is located on the second main body 12, and the two ends of the flexible pipe 53 are connected to the fan 51 and the air duct 52 respectively.

[0067] The blower 51 directly draws inert gas from the cleaning chamber and sends it into the air duct 52 through the flexible pipe 53. The inert gas is then sprayed out of the air duct 52 and returned directly to the cleaning chamber.

[0068] In some examples, please refer to Figure 3 The second main body 12 has an arc-shaped guide body 23 at its far end. The positional relationship between the arc-shaped guide body 23, the recovery channel 4 and the purge pipe 22 is as follows: the recovery channel 4 is located inside the arc-shaped guide body 23, and the second end of the purge pipe 22 is located outside the arc-shaped guide body 23.

[0069] The functions of the arc-shaped guide 23 are as follows: guiding the flow direction of the cleaning gas, limiting the flow range of the cleaning gas, and making the cleaning gas more concentrated.

[0070] In addition, the gap between the arc-shaped guide 23 and the substrate changes when it moves. When performing non-planar cleaning, the gap width between the arc-shaped guide 23 and the substrate can be appropriately reduced to improve the cleaning effect.

[0071] Furthermore, the axis of the second end of the purge pipe 22 is parallel to the tangent at the location of the second end of the purge pipe 22 at the position of the arc-shaped guide body 23.

[0072] Furthermore, the arc-shaped guide body 23 is provided with an arc-shaped guide ring 24. The positional relationship between the arc-shaped guide ring 24 and the second end of the purge pipe 22 and the arc-shaped guide body 23 is such that the second end of the purge pipe 22 is located between the arc-shaped guide body 23 and the arc-shaped guide ring 24.

[0073] Furthermore, in the direction of gas flow, the distance between the outer wall of the arc-shaped guide body 23 and the inner wall of the arc-shaped guide ring 24 is equal everywhere.

[0074] The arc-shaped guide body 23, in conjunction with the arc-shaped guide ring 24, can improve the controllability of the flow direction and flow range of the cleaning gas, and can also make the cleaning gas more concentrated, reducing waste caused by overflow.

[0075] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A cleaning system for a silicon nitride etch screen, comprising: The utility model relates to a kind of plasma cleaning device, including: First body (11) and the second body (12) rotationally connected with first body (11); Cleaning pipeline (2), including the main pipeline (21) being arranged in first body (11) and the purge pipeline (22) being arranged in second body (12), the quantity of purge pipeline (22) is multiple and all with main pipeline (21) communication; Plasma generator (3) is connected with main pipeline (21); Recovery channel (4) passes through first body (11) and second body (12); Wherein, the axis of recovery channel (4) and the axis of main pipeline (21) coincide and recovery channel (4) is located inside main pipeline (21); Multiple purge pipeline (22) is evenly arranged around the axis of recovery channel (4); The first end of purge pipeline (22) is communicated with main pipeline (21), and the second end of purge pipeline (22) is inclined to the direction close to recovery channel (4); Arc-shaped guide body (23) is arranged on the lower end of second body (12), recovery channel (4) is located on the inner side of arc-shaped guide body (23), and the second end of purge pipeline (22) is located on the outer side of arc-shaped guide body (23); Arc-shaped guide ring (24) is arranged on the lower end of second body (12); The second end of purge pipeline (22) is located between arc-shaped guide body (23) and arc-shaped guide ring (24); In the direction of gas flow, the distance between the outer wall of arc-shaped guide body (23) and the inner wall of arc-shaped guide ring (24) is equal everywhere.

2. The cleaning system of claim 1, wherein The area of the surrounding area of purge pipeline (22) on photoresist layer is one half to two thirds of the area of the surrounding area of purge pipeline (22).

3. The cleaning system of the silicon nitride etching mask according to claim 1 or 2, wherein Wind baffle curtain wall (5) is arranged on second body (12), and the coverage area of purge pipeline (22) is located inside the coverage area of wind baffle curtain wall (5); Wind baffle curtain wall (5) is inclined to the direction away from recovery channel (4).

4. The cleaning system of claim 3, wherein the cleaning system further comprises a second cleaning chamber. Wind baffle curtain wall (5) extracts gas from the surrounding environment.

5. The cleaning system of claim 3, wherein the cleaning system further comprises a second cleaning chamber. Wind baffle curtain wall (5) includes: Fan (51); Air duct (52) is arranged on second body (12); Flexible pipeline (53) is connected with fan (51) and air duct (52) respectively at two ends.

6. The cleaning system of claim 4, wherein the cleaning system further comprises a second cleaning chamber. Plasma generator (3) uses exogenous gas to generate plasma.

7. The cleaning system of claim 1, wherein the cleaning system is configured to clean a silicon nitride etch screen. The axis of the second end of purge pipeline (22) is parallel to the tangent of the position of the second end of purge pipeline (22) in arc-shaped guide body (23).

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