Coating system for silicon nitride etching cover plate
By using multiple atomizers and spiral gas flow channels in the silicon nitride etching cover coating system, the distribution of photoresist particles is solved, and the problem of uneven film formation thickness of photoresist is achieved. Even coating distribution.
Patent Information
- Application Number
- CN202411369321.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2025-01-03
AI Technical Summary
During the coating process of silicon nitride etching cover plate, the prior art is difficult to ensure the uniformity of the film forming thickness of the photoresist, especially in the atomized area and edges, there are problems of density unevenness and thickness unevenness.
A coating system is designed, including a nozzle housing, channel, atomizer and a spiral gas flow channel, through a combination of multiple atomizers and spiral air flow channels to adjust the shape and air flow velocity of the atomization area to ensure light The uniform distribution of resist particles on the silicon nitride etch cover.
By actively controlling the shape and airflow velocity of the atomized area, the uniformity of the photoresist film formation thickness is significantly improved, and the thickness unevenness caused by edge overlap and uncontrollable coverage is reduced.
Smart Images
Figure CN119237196A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of chip manufacturing technology, and in particular to a coating system for a silicon nitride etching cover plate. Background Art
[0002] The current mainstream process methods for coating photoresist on silicon nitride etching cover are spin coating and spray coating.
[0003] Spin coating is an efficient photoresist coating process that provides highly uniform coatings. In this process, a small amount of photoresist (usually a few milliliters) is dispensed onto a substrate that is spinning at high speeds, with typical rotation speeds of several thousand revolutions per minute (usually around 4000 rpm).
[0004] Photoresist can be dispensed when the substrate is stationary and then accelerated (static spin coating), or it can be dispensed while the substrate is already rotating (dynamic spin coating). During the rotation process, the centrifugal force on the substrate surface peels off the excess photoresist from the edge, causing the photoresist to spread into a uniform film.
[0005] The disadvantage of spin coating is that if the substrate surface has a large number of features or complex topography, the uniformity of the film thickness may be affected. In holes or recessed areas, the buildup of photoresist may result in thicker films at the edges of the features and thinner films in other areas.
[0006] The advantage of spray coating is that the film thickness is uniform and it is suitable for large-area spray coating. In the context of large-diameter wafers, the advantages of spray coating are becoming more and more obvious. The disadvantage of spray coating is the uniformity of spatial distribution of photoresist atomized particles and the uneven thickness caused by edge overlap.
[0007] For example, ultrasonic atomizing nozzles have obvious advantages in photoresist atomization, but it will cause the atomization area to increase. The density of photoresist particles at the edge of the atomization area is lower than the density of particles at the center. At the same time, if the air flow speed is too fast, it will increase the difficulty of controlling the film thickness. Summary of the invention
[0008] The present application provides a coating system for a silicon nitride etching cover plate, which can adjust the shape and moving speed of the atomization area by actively controlling the atomization area, so that the film thickness of the photoresist on the silicon nitride etching cover plate is more uniform.
[0009] The above-mentioned purpose of the present application is achieved through the following technical solutions:
[0010] The present application provides a coating system for a silicon nitride etching cover plate, comprising:
[0011] Nozzle housing;
[0012] The channel is arranged inside the nozzle shell, and the channel includes an atomization channel, a transition channel and a gas uniformity channel connected in sequence.
[0013] An atomizer is arranged inside the nozzle housing, and an atomizing end of the atomizer extends into the atomizing channel;
[0014] A plurality of spiral gas flow channels are arranged on the inner wall of the gas uniform passage, a jet port is arranged at the proximal end of the spiral gas flow channel, and a suction port is arranged at the distal end of the spiral gas flow channel;
[0015] The flow area of the gas uniformity channel is larger than the flow area of the atomization channel;
[0016] The flow area of the transition channel tends to increase in the direction close to the gas uniform channel.
[0017] In a possible implementation of the present application, there are multiple atomizers;
[0018] The atomizing ends of the plurality of atomizers are evenly arranged around the axis of the atomizing channel.
[0019] In a possible implementation of the present application, there are multiple groups of atomizers in a direction close to the transition channel, and the number of atomizers in each group is the same;
[0020] In the direction approaching the transition channel, the spacing between the atomizing ends of adjacent atomizers tends to increase.
[0021] In a possible implementation of the present application, the air jet port is close to the transition channel, and the air suction port is close to the end of the gas uniformity channel.
[0022] In a possible implementation of the present application, an interception ring is provided at the end of the gas uniformity channel, and the inner diameter of the interception ring is smaller than the inner diameter at the end of the gas uniformity channel.
[0023] In a possible implementation of the present application, in a direction close to the center of the gas uniform channel, the interception ring is inclined toward a direction close to the transition channel.
[0024] In a possible implementation of the present application, a regulating chamber is provided on the gas uniformity channel;
[0025] In the direction away from the transition channel, the flow area of the regulating cavity tends to increase first and then decrease.
[0026] In a possible implementation of the present application, the flow area of the end of the regulating chamber away from the transition channel is smaller than the flow area of the end close to the transition channel.
[0027] In a possible implementation of the present application, a reflux channel is provided on the inner wall of the regulating chamber, a first end of the reflux channel is located at one end of the regulating chamber away from the transition channel, and a second end of the reflux channel is used to connect to the negative pressure chamber. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 It is a schematic diagram of the appearance of a coating system provided in this application.
[0029] Figure 2 It is an internal schematic diagram of a coating system provided in this application.
[0030] Figure 3 This is a distribution diagram of an atomizer provided in this application.
[0031] Figure 4 It is a schematic diagram of the development of a spiral gas flow channel provided by the present application.
[0032] In the figure, 1, nozzle housing, 2, channel, 3, atomizer, 4, spiral gas flow channel, 21, atomization channel, 22, transition channel, 23, gas uniformity channel, 24, interception ring, 25, adjustment chamber, 26, reflux channel, 41, jet port, 42, air intake port. DETAILED DESCRIPTION
[0033] The technical solution in this application is further described in detail below in conjunction with the accompanying drawings.
[0034] This application discloses a coating system for silicon nitride etching cover plate, see Figure 1 and Figure 2 In some examples, the coating system for silicon nitride etching cover plate disclosed in the present application includes a nozzle housing 1, a channel 2, an atomizer 3 and a spiral gas flow channel 4, and the channel 2, the atomizer 3 and the spiral gas flow channel 4 are all located inside the nozzle housing 1.
[0035] The channel 2 is divided into three parts, namely, an atomization channel 21, a transition channel 22 and a gas uniformization channel 23. In the flow direction of the photoresist, the atomization channel 21, the transition channel 22 and the gas uniformization channel 23 are connected in sequence.
[0036] The atomizing end of the atomizer 3 extends into the atomizing channel 21, and its function is to generate ultrasonic waves through high-frequency vibrations, which can atomize the liquid photoresist, so that the liquid photoresist is changed into particles and distributed in the space in the atomizing channel 21. Because the photoresist flows into the atomizing channel 21 at a certain speed, the photoresist will continue to flow forward after being atomized.
[0037] In some possible implementations, there are multiple atomizers 3, and the atomizing ends of the multiple atomizers 3 are evenly arranged around the axis of the atomizing channel 21. The purpose of adding the atomizer 3 is to increase the atomization area to obtain a better atomization effect.
[0038] The distance between the atomizing ends of adjacent atomizers 3 is greater than the working influence range of the atomizing ends of the atomizers.
[0039] See also Figure 3 Further, there are multiple groups of atomizers 3 in the direction close to the transition channel 22, the number of atomizers 3 in each group is the same, and in the direction close to the transition channel 22, the interval between the atomization ends of adjacent atomizers 3 tends to increase.
[0040] That is, the atomizing end of the atomizer 3 begins to move toward the direction close to the inner wall of the atomizing channel 21. This is because it is necessary to provide a flow area for the atomized photoresist (hereinafter referred to as photoresist particles), reduce the interception effect of the atomizing end of the atomizer 3, and at the same time atomize the photoresist adhering to the inner wall of the atomizing channel 21 to avoid the accumulation of photoresist on the inner wall of the atomizing channel 21.
[0041] See also Figure 2 and Figure 4 The spiral gas flow channel 4 is arranged on the inner wall of the gas uniform passage 23, the proximal end of the spiral gas flow channel 4 is provided with an air jet 41, and the distal end of the spiral gas flow channel 4 is provided with an air intake port 42. The function of the air jet 41 is to inject flowing air into the spiral gas flow channel 4, and the air intake port 42 is to transfer the flowing air in the spiral gas flow channel 4 to the outside of the spiral gas flow channel 4.
[0042] As for the air jet 41 and the air intake port 42 , it can be seen in the figure that they are made by splitting and then butting and merging, and the connection between the air jet 41 and the air intake port 42 and the spiral gas flow channel 4 is covered with a cover plate to allow the air flow to flow along the spiral gas flow channel 4 .
[0043] The function of the spiral gas flow channel 4 is to generate a continuous airflow rotating around the axis of the gas uniform channel 23 inside the gas uniform channel 23, that is, a spiral airflow. The spiral airflow has two functions: one is to change the moving trajectory of the photoresist particles, and the other is to improve the uniformity of the distribution of the photoresist particles in the spatial range.
[0044] It should be understood that the flow mode of the photoresist particles in the atomization channel 21 is to move along the center line direction of the atomization channel 21. In the initial stage of entering the gas uniformity channel 23, the movement mode of the photoresist particles remains unchanged, but under the influence of the spiral airflow, the movement mode of the photoresist particles begins to change to a spiral advance.
[0045] At this time, the large-size particles in the photoresist particles will move toward the inner wall of the gas uniform channel 23 under the action of centrifugal force, and then leave the gas uniform channel 23 with the spiral airflow. The photoresist particles in the middle of the gas uniform channel 23 will also move toward the inner wall of the gas uniform channel 23 under the action of centrifugal force, so that the distribution of the photoresist particles in the gas uniform channel 23 tends to be uniform. This is because in the atomization stage, the distribution density of the photoresist particles near the inner wall of the channel 2 is naturally at a disadvantage, and needs to be corrected with the help of the gas uniform channel 23 (spiral airflow).
[0046] The flow area of the gas uniform channel 23 is larger than the flow area of the atomization channel 21, and the flow area of the transition channel 22 tends to increase in the direction close to the gas uniform channel 23. The above contents are used to appropriately reduce the flow speed of the photoresist particles and provide sufficient time for the spiral airflow to adjust the distribution density of the photoresist particles.
[0047] For some possible implementations, see Figure 2 An adjusting chamber 25 is provided on the gas uniform passage 23 . The adjusting chamber 25 has a shape in which, in a direction away from the transition passage 22 , the flow area of the adjusting chamber 25 first tends to increase and then tends to decrease.
[0048] According to the records in the previous article, it can be seen that the distribution density of photoresist particles near the inner wall of the channel 2 is at a natural disadvantage. In order to further improve this problem, an adjustment chamber 25 is added to the gas uniform channel 23. According to the shape of the adjustment chamber 25, it can be seen that the adjustment chamber 25 can make the photoresist particles entering the gas uniform channel 23 first diffuse into the photoresist particle adjustment chamber 25.
[0049] That is, the adjustment cavity 25 can intercept the photoresist particles located at the edge position.
[0050] Furthermore, the flow area of the end of the regulating chamber 25 away from the transition channel 22 is smaller than the flow area of the end close to the transition channel 22 , which can further improve the interception effect of the regulating chamber 25 .
[0051] Furthermore, a reflux channel 26 is provided on the inner wall of the regulating chamber 25, a first end of the reflux channel 26 is located at an end of the regulating chamber 25 away from the transition channel 22, and a second end of the reflux channel 26 is used to connect with the negative pressure chamber.
[0052] The function of the reflux channel 26 is to remove the photoresist particles that flow directly into the regulating chamber 25 , and the removal method is to extract the photoresist particles retained in the regulating chamber 25 by means of negative pressure.
[0053] It should be noted here that the opening mode of the reflux channel 26 is intermittent opening rather than continuous opening.
[0054] In some examples, the air jet 41 is close to the transition channel 22 , and the air inlet 42 is close to the end of the gas uniform channel 23 , so that the spiral airflow can achieve a higher coverage rate on the inner wall of the gas uniform channel 23 .
[0055] For some examples, see Figure 2 An interception ring 24 is provided at the end of the gas uniform channel 23. The inner diameter of the interception ring 24 is smaller than the inner diameter at the end of the gas uniform channel 23. The function of the interception ring 24 is to shape the occupied space of the photoresist particles flowing out of the gas uniform channel 23, or it can be described as that the interception ring 24 can clearly define the coverage range of the photoresist particles.
[0056] In this way, when moving the coating system for silicon nitride etching cover plate disclosed in the present application, the uneven film thickness caused by overlapping coverage due to uncontrollable edges can be ignored.
[0057] Further, in the direction close to the center of the gas uniform channel 23, the interception ring 24 is inclined toward the direction close to the transition channel 22. The photoresist particles intercepted by the interception ring 24 are re-liquefied on the interception ring 24, and then leave the gas uniform channel 23 with the spiral gas flow.
[0058] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.
Claims
1. A coating system for a silicon nitride etching cover plate, characterized in that: include: Nozzle housing (1); The channel (2) is arranged inside the nozzle housing (1), and the channel (2) includes an atomization channel (21), a transition channel (22) and a gas uniformity channel (23) which are connected in sequence. An atomizer (3) is arranged inside the nozzle housing (1), and an atomizing end of the atomizer (3) extends into the atomizing channel (21); A plurality of spiral gas flow channels (4) are arranged on the inner wall of the gas uniform passage (23), a jet port (41) is arranged at the proximal end of the spiral gas flow channel (4), and a suction port (42) is arranged at the distal end of the spiral gas flow channel (4); The flow area of the gas uniformity channel (23) is greater than the flow area of the atomization channel (21); In the direction approaching the gas uniform passage (23), the flow area of the transition passage (22) tends to increase.
2. The coating system for silicon nitride etching cover plate according to claim 1, characterized in that: The number of atomizers (3) is multiple; The atomizing ends of the plurality of atomizers (3) are evenly arranged around the axis of the atomizing channel (21).
3. The coating system for silicon nitride etching cover plate according to claim 2, characterized in that: There are multiple groups of atomizers (3) in a direction close to the transition channel (22), and the number of atomizers (3) in each group is the same; In the direction approaching the transition channel (22), the intervals between the atomizing ends of adjacent atomizers (3) tend to increase.
4. The coating system for silicon nitride etching cover plate according to claim 1, characterized in that: The air injection port (41) is close to the transition channel (22), and the air suction port (42) is close to the end of the gas uniform passage (23).
5. The coating system for silicon nitride etching cover plate according to claim 4, characterized in that: An interception ring (24) is provided at the end of the gas uniformity channel (23), and the inner diameter of the interception ring (24) is smaller than the inner diameter at the end of the gas uniformity channel (23).
6. The coating system for silicon nitride etching cover plate according to claim 5, characterized in that: In a direction close to the center of the gas uniform passage (23), the interception ring (24) is inclined in a direction close to the transition passage (22).
7. The coating system for silicon nitride etching cover plate according to claim 1, characterized in that: The gas uniform passage (23) is provided with an adjustment chamber (25); In the direction away from the transition channel (22), the flow area of the regulating chamber (25) tends to increase first and then decrease.
8. The coating system for silicon nitride etching cover plate according to claim 7, characterized in that: The flow area of the end of the regulating chamber (25) away from the transition channel (22) is smaller than the flow area of the end close to the transition channel (22).
9. The coating system for silicon nitride etching cover plate according to claim 1 or 7, characterized in that: A reflux channel (26) is provided on the inner wall of the regulating chamber (25), a first end of the reflux channel (26) is located at an end of the regulating chamber (25) away from the transition channel (22), and a second end of the reflux channel (26) is used for connecting to the negative pressure chamber.