Method for cleaning a teos chemical vapor deposition process chamber and storage medium
By improving the cleaning method in the TEOS chemical vapor deposition process, and adopting a technique of first evacuating the gas and then lowering the heating plate in stages, and using a combination of helium and oxygen for cleaning, the problem of particles being stirred up when the heating plate moves was solved, resulting in higher product quality and cleaning effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGSU XINGAN TECH CO LTD
- Filing Date
- 2024-12-25
- Publication Date
- 2026-07-21
AI Technical Summary
In the TEOS chemical vapor deposition process, when the heating plate moves after film deposition, microparticles are easily stirred up, resulting in a high number of particles on the product surface and affecting product quality.
After thin film deposition is completed, the process chamber and pipeline are cleaned by evacuation instead of exhaust. The heating plate is lowered in stages while maintaining constant pressure in the process chamber until the heating plate is in place. A combination of helium and oxygen is used for cleaning, with a method of coarse evacuation followed by fine evacuation.
It effectively reduces the number of particles in the process cavity, improves product quality and cleaning effect, reduces particle adhesion on the wafer surface, and improves the processing qualification rate.
Smart Images
Figure CN119685798B_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of semiconductor manufacturing, and specifically relates to a cavity cleaning method and storage medium for TEOS chemical vapor deposition process. Background Technology
[0002] The traditional TEOS high-density plasma-enhanced chemical vapor deposition (TEOS) process mainly includes the following steps: placing the substrate to be processed (such as a silicon wafer) in an appropriate position within the reaction chamber, injecting tetraethoxysilane (TEOS) and other auxiliary gases, such as oxygen, argon, or helium, into the reaction chamber; after heating to a predetermined temperature for thin film deposition, turning off the reaction gas, cleaning the chamber, and completing the vapor deposition process.
[0003] In existing technologies, the cavity cleaning process after thin film deposition mainly involves shutting off the reaction gas, introducing auxiliary gas into the process cavity to expel byproducts and residual gases, and then using a vacuum pump to extract the byproducts and residual gases. However, after thin film deposition, the heating plate needs to be moved from the processing position to the release position, i.e., the heating plate needs to be lowered to the release position. This process easily stirs up a large number of particles in the process cavity, resulting in a high particle count on the surface of the product after the reaction, which greatly affects the product quality.
[0004] Therefore, a cavity cleaning method for the TEOS chemical vapor deposition process is needed to solve the above problems. Summary of the Invention
[0005] To address the shortcomings of the prior art, this application provides a TEOS chemical vapor deposition process chamber cleaning method and storage medium. After thin film deposition, the method changes from venting to evacuation, and then uses inert gas to clean the process chamber and pipelines. The process is improved by venting and evacuating in stages, thereby effectively reducing the number of particles.
[0006] The technical effect to be achieved in this application is accomplished through the following solution:
[0007] According to a first aspect of this application, a method for cleaning a cavity in a TEOS chemical vapor deposition process is provided, comprising the following steps:
[0008] Step 1: Extract byproducts and residual gases from the process chamber and pipelines until the first condition is met;
[0009] Step 2: Purge the pipelines and process chambers with cleaning gas until the second condition is met;
[0010] Step 3: While maintaining constant pressure during cleaning within the process chamber, control the heating plate to descend continuously in stages;
[0011] Step 4: Once the heating plate is in place, fully open the vacuum pump to bring the base pressure into the process chamber, thus completing the cleaning of the process chamber.
[0012] Preferably, in step 1, the first condition is an air extraction time of 5 seconds.
[0013] Preferably, in step 1, the air is pumped out using a vacuum pump with the valve fully open.
[0014] Preferably, in step 2, the cleaning gas includes helium and / or oxygen.
[0015] Preferably, helium is introduced into the TEOS-related pipelines and valves to purge TEOS residues; oxygen is introduced into other pipelines until it enters the process chamber simultaneously with helium for purging, until the second condition is met.
[0016] Preferably, the second condition is an exhaust time of 5 seconds.
[0017] Preferably, in step 3, maintaining constant pressure during cleaning within the process chamber specifically involves: continuously introducing cleaning gas for cleaning and maintaining vacuum pump evacuation to keep the pressure within the process chamber constant.
[0018] Preferably, when cleaning is performed by introducing cleaning gas, the introduced cleaning gas is oxygen.
[0019] Preferably, the specific method for controlling the continuous descent of the heating plate in stages is as follows:
[0020] Within 2 seconds, the heating plate is controlled to decrease from 280 mils to 500 mils;
[0021] Then, the heating plate is slowly lowered to 600 mils at a rate of 20 mils per second.
[0022] Finally, the heating plate is controlled to decrease from 600 mils to 900 mils within 5 seconds.
[0023] According to a second aspect of this application, a computer-readable storage medium is provided, wherein a computer program is stored in the computer-readable storage medium, and when the computer program is executed, it implements the above-described TEOS chemical vapor deposition process cavity cleaning method.
[0024] According to one embodiment of this application, the beneficial effect of using the TEOS chemical vapor deposition process cavity cleaning method is that this method does not require equipment modification. By simply optimizing the combination of exhaust cleaning and gas extraction, the number of particles is greatly reduced while removing by-products and residual gases, thus ensuring product quality and cleaning effect.
[0025] This method employs a coarse extraction followed by a fine extraction, which facilitates the discharge of byproducts and residual gases, and allows for a more thorough cleaning of the gaps in the heating plate, pipes, and valves. Attached Figure Description
[0026] To more clearly illustrate the embodiments of this application or the existing technical solutions, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1 This is a flowchart of a cavity cleaning method for a TEOS chemical vapor deposition process according to an embodiment of this application. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0029] like Figure 1 As shown, a TEOS chemical vapor deposition process cavity cleaning method in one embodiment of this application includes the following steps:
[0030] Step 1: Extract byproducts and residual gases from the process chamber and pipelines until the first condition is met;
[0031] In this step, a vacuum pump is connected to the rear end of the process chamber, and an input pipeline for the reaction gas and the purge gas is connected to the front end of the process chamber. A flow regulating valve is installed on the pipeline to convert some of the gas from liquid to gas.
[0032] After the thin film is deposited and formed, the cleaning step of the process chamber needs to be started, that is, the residual reaction gas and by-products are discharged. At this time, the valve of the vacuum pump is opened, and the by-products and residual gas in the process chamber and upstream pipeline are extracted with the valve fully open. The first condition is set to 5 seconds, so the vacuum pump continues to extract for 5 seconds before proceeding to the next step.
[0033] In other embodiments, other times or conditions may be set as the first condition depending on the process, such as setting the pressure in the process chamber to reach a certain threshold as the first condition.
[0034] Because the temperature inside the chamber is high during the vapor deposition process, usually around 400°C, and the pressure inside the chamber is high during TEOS high-density plasma-enhanced chemical vapor deposition, a vacuum pump is used in this step to pre-extract some by-products and residual gases, which can reduce the pressure inside the chamber and reduce air disturbance caused by direct exhaust.
[0035] Step 2: Purge the pipelines and process chambers with cleaning gas until the second condition is met;
[0036] In this step, the purging gas includes helium and / or oxygen, and the specific method is as follows:
[0037] Open the helium flow regulating valve and introduce helium into the TEOS-related pipeline to purge the TEOS residue in the pipeline and related valves for 5 seconds. Control the helium flow rate to 1000 sccm (1000 standard cubic centimeters per minute) through the flow control valve to purge the residue in the TEOS-related pipeline until it enters the process chamber.
[0038] Open the oxygen flow regulating valve and introduce oxygen into all pipelines except those related to TEOS to purge them until it enters the process chamber simultaneously with helium for 5 seconds. Control the oxygen flow rate to 1000 sccm (1000 standard cubic centimeters per minute) using the flow control valve, and introduce it into the process chamber along with helium to purge the process chamber. During the purging process, keep the vacuum pump valve fully open to facilitate the blowing out of the process chamber of TEOS residues and byproducts.
[0039] In other embodiments, other times or conditions may be set as the second condition depending on the process, such as setting the pressure in the process chamber to reach a certain threshold as the second condition.
[0040] Step 3: While maintaining constant pressure during cleaning within the process chamber, control the heating plate to descend continuously in stages;
[0041] In this step, after the above steps are completed, close the helium flow regulating valve and leave only the oxygen flow regulating valve open, maintaining the oxygen flow rate at 840 sccm, or 840 standard cubic centimeters per minute.
[0042] Adjust the valve of the vacuum pump to maintain the pressure at 5 torr. Gradually evacuate while continuing to introduce oxygen for purging, keeping the pressure in the process chamber constant to continuously clean all pipes and the process chamber.
[0043] The specific method for gradual evacuation is as follows: while the heating plate continues to descend into position, keep the valve of the vacuum pump fixed to maintain the pressure until the heating plate descends into position and is fully opened.
[0044] This step uses oxygen for cleaning, which is cheaper than helium, thus reducing cleaning costs.
[0045] Moreover, helium is lighter and less effective at cleaning large particles, while oxygen, which is heavier, is more effective at removing particles.
[0046] Oxygen can react with residual TEOS to carry it away, but it is not enough to form photoresist material and thus will not contaminate the cavity.
[0047] When oxygen is introduced, a fixed pressure is maintained in the process chamber, and the position of the heating plate is controlled to descend. When the volume changes, the airflow will not change due to pressure changes, thus avoiding the stirring up of more particles.
[0048] As the heating plate in the process chamber descends, its volume changes. While maintaining a constant pressure within the process chamber, the heating plate continues to descend until it reaches its final position. Then, the angle of the butterfly valve on the vacuum pump is controlled to open it fully, thereby thoroughly purging the butterfly valve.
[0049] The specific method for controlling the continuous descent of the heating plate in stages is as follows:
[0050] Within 2 seconds, the heating plate is controlled to decrease from 280 mils to 500 mils;
[0051] Then, the heating plate is slowly lowered to 600 mils at a speed of 20 mils per second. That is, during the process of the heating plate height from 500 mils to 600 mils, it is at 500 mils, 520 mils, 540 mils, 560 mils, 580 mils and 600 mils respectively, each step is 1 second, and each step is a 20 mils drop. The step-by-step lowering can leave enough time to blow on all parts of the heating plate drive component.
[0052] Finally, within 5 seconds, the heating plate is controlled to drop from 600 mils to 900 mils, reaching the final position.
[0053] The positions mentioned above, from 280 mils to 900 mils, refer to the distance between the heating plate and the top spray head. A mil is a unit of length, equal to one-thousandth of a foot. During cleaning, the heating plate needs to be lowered to the bottom to ensure that the cleaning gas can pass through smoothly.
[0054] The time it takes for the heating plate to move from the process position (290 mils) to the release position (900 mils) is about 4 seconds. Since the driving part of the heating plate extends into the process cavity, there is a small gap between it and the bottom of the process cavity. It is difficult to clean this gap after the heating plate is lowered directly into position. Therefore, in this step, a step-by-step, slow descent method is adopted to facilitate the blowing away of by-products and residues in the gap of the heating plate driving part.
[0055] At the same time, the slow descent method can also reduce the disturbance to the air in the process cavity, reduce the number of particles being lifted, and reduce the probability of particles reaching the wafer surface.
[0056] Step 4: Once the heating plate is in place, the vacuum pump is fully turned on to bring the base pressure into the process chamber, completing the cleaning of the process chamber and preparing it for the processing of the next wafer.
[0057] Through the above steps, residual gas in the process chamber is pre-extracted, reducing the pressure in the process chamber and preventing air fluctuations when the purge gas valve is opened, thereby reducing the particle lifting caused by air disturbance. During the purge gas introduction stage, the pressure in the process chamber is kept balanced, ensuring a stable airflow through the purge pipeline and process chamber, further avoiding air disturbance. The slow descent of the heating plate allows sufficient time for cleaning the gaps, and due to the slow descent and constant pressure, no significant air disturbance is caused, ensuring that particles generated by the movement of the heating plate are swept away by the stable airflow and do not rise and fall onto the wafer surface.
[0058] Through multiple experiments, the surface particle size distribution of wafers obtained using this method after thin film deposition on the wafer surface is shown in Table 1 compared to the wafers obtained by traditional cavity cleaning.
[0059] Table 1 Comparison of particles on PETEOS 6K membrane using the traditional method and the method of this embodiment.
[0060]
[0061] As can be seen from the table above, wafers processed using traditional methods have a large number of particles (0.2μm) on the film, usually around 30 particles, and sometimes as high as 45. This has a significant impact on subsequent chip production and is not conducive to improving the yield rate.
[0062] The wafers processed using the method in this embodiment show a significant reduction in particles on the film, with only a single-digit number of particles present. This demonstrates that the method greatly reduces the number of particles while ensuring complete cleaning of the process cavity, thereby helping to improve the wafer processing yield.
[0063] One embodiment of this application provides a computer-readable storage medium storing a computer program that, when executed, implements the above-described TEOS chemical vapor deposition process cavity cleaning method.
[0064] According to one embodiment of this application, the beneficial effect of using the TEOS chemical vapor deposition process cavity cleaning method is that this method does not require equipment modification. By simply optimizing the combination of exhaust cleaning and gas extraction, the number of particles is greatly reduced while removing by-products and residual gases, thus ensuring product quality and cleaning effect.
[0065] This method employs a coarse extraction followed by a fine extraction, which facilitates the discharge of byproducts and residual gases, and allows for a more thorough cleaning of the gaps in the heating plate, pipes, and valves.
[0066] It should be noted that the above detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0067] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0068] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.
[0069] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.
[0070] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, such as rotated 90 degrees or in other orientations, and the spatial relative descriptions used herein will be interpreted accordingly.
[0071] In the detailed description above, reference has been made to the accompanying drawings, which form part of this document. In the drawings, similar symbols typically identify similar parts unless the context otherwise indicates otherwise. The illustrated embodiments described in the detailed specification, drawings, and claims are not intended to be limiting. Other embodiments may be used and other changes may be made without departing from the spirit or scope of the subject matter presented herein.
[0072] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for cleaning the cavity in a TEOS chemical vapor deposition process, characterized in that, Includes the following steps: Step 1: Extract byproducts and residual gases from the process chamber and pipelines until the first condition is met; Step 2: Purge the pipelines and process chambers with cleaning gas until the second condition is met; Step 3: While maintaining constant pressure during cleaning within the process chamber, control the heating plate to descend continuously in stages; Step 4: Once the heating plate is in place, fully open the vacuum pump to bring the base pressure into the process chamber, thus completing the cleaning of the process chamber.
2. The TEOS chemical vapor deposition process cavity cleaning method according to claim 1, characterized in that, In step 1, the first condition is an air extraction time of 5 seconds.
3. The TEOS chemical vapor deposition process cavity cleaning method according to claim 2, characterized in that, In step 1, air is pumped out using a vacuum pump with the valve fully open.
4. The TEOS chemical vapor deposition process cavity cleaning method according to claim 2, characterized in that, In step 2, the cleaning gas includes helium and / or oxygen.
5. The TEOS chemical vapor deposition process cavity cleaning method according to claim 4, characterized in that, Helium is introduced into the TEOS-related pipelines and valves to purge TEOS residues; oxygen is introduced into other pipelines until it enters the process chamber along with helium for purging, until the second condition is met.
6. The TEOS chemical vapor deposition process cavity cleaning method according to claim 5, characterized in that, The second condition is an exhaust time of 5 seconds.
7. The TEOS chemical vapor deposition process cavity cleaning method according to claim 5, characterized in that, In step 3, maintaining constant pressure during cleaning within the process chamber specifically involves: continuously introducing cleaning gas for cleaning and maintaining vacuum pump evacuation to keep the pressure within the process chamber constant.
8. The TEOS chemical vapor deposition process cavity cleaning method according to claim 7, characterized in that, When cleaning, the cleaning gas is oxygen.
9. The TEOS chemical vapor deposition process cavity cleaning method according to claim 8, characterized in that, The specific method for controlling the continuous descent of the heating plate in stages is as follows: Within 2 seconds, the distance between the heating plate and the top spray head is reduced from 280 mils to 500 mils; Then, the distance between the heating plate and the top spray head is gradually reduced to 600 mils at a rate of 20 mils per second. Finally, within 5 seconds, the distance between the heating plate and the top spray head was reduced from 600 mils to 900 mils.
10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed, implements the TEOS chemical vapor deposition process cavity cleaning method according to any one of claims 1 to 9.