TEOS chemical vapor deposition process cavity cleaning method and storage medium

Abstract

The invention discloses a TEOS chemical vapor deposition process cavity cleaning method. The method comprises the following steps that 1, by-products and residual gas in a process cavity and a pipeline are extracted till a first condition is met; 2, sweeping gas is introduced into the pipeline and the process cavity for sweeping till a second condition is met; step 3, gradually exhausting air, and controlling the heating disc to continuously descend step by step at the same time; and 4, until the heating disc is in place, the vacuum pump is completely opened to enable the interior of the process cavity to reach base pressure, and cleaning of the process cavity is completed. According to the method, equipment does not need to be improved, only by optimizing combined change of exhaust sweeping and air exhaust, the number of particles is greatly reduced while byproducts and residual gas are exhausted, and the product quality and the sweeping effect are guaranteed; according to the method, rough extraction is conducted firstly, then fine extraction is conducted, discharging of by-products and residual gas is better facilitated, and gaps of the heating disc, the pipeline and the valve can be cleaned more thoroughly.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor production, and in particular relates to a TEOS chemical vapor deposition process chamber cleaning method and a storage medium. Background Art

[0002] The steps of the traditional TEOS high-density plasma enhanced chemical vapor deposition (TEOS) process mainly include: placing the substrate to be processed (such as a silicon wafer) at an appropriate position in 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 the prior art, after thin film deposition, the step of cleaning the chamber is mainly to introduce auxiliary gas into the process chamber to discharge by-products and residual gases after turning off the reaction gas, and then use a vacuum pump to extract the by-products and residual gases. However, after the thin film deposition is completed, the heater position needs to be moved from the process position to the release position, that is, the heater position needs to be lowered to the release position. In this process, a large number of particles are easily raised in the process chamber, resulting in a high number of particles on the surface of the product after the reaction, which greatly affects the quality of the product.

[0004] Therefore, a cavity cleaning method for a TEOS chemical vapor deposition process is needed to solve the above problems. Summary of the invention

[0005] In order to address the deficiencies of the prior art, the present application provides a TEOS chemical vapor deposition process chamber cleaning method and storage medium. After the thin film deposition is completed, exhaust is changed to vacuum, and then the process chamber and pipeline are cleaned with inert gas. The exhaust and vacuum are performed in steps, and the procedure is improved to effectively reduce the number of particles.

[0006] The technical effects to be achieved by this application are achieved through the following solutions:

[0007] According to a first aspect of the present application, a TEOS chemical vapor deposition process chamber cleaning method is provided, comprising the following steps:

[0008] Step 1: extracting byproducts and residual gases in the process chamber and pipeline until the first condition is reached;

[0009] Step 2: introducing a purge gas into the pipeline and the process chamber for purge until the second condition is reached;

[0010] Step 3: While maintaining constant pressure cleaning in the process chamber, control the heating plate to continue to descend in steps;

[0011] Step 4: Until the heating plate is in place, the vacuum pump is fully opened to make the base pressure in the process chamber reach the base pressure, and the cleaning of the process chamber is completed.

[0012] Preferably, in step 1, the first condition is a pumping time of 5 s.

[0013] Preferably, in step 1, vacuum is carried out using a vacuum pump with the valve fully opened.

[0014] Preferably, in step 2, the purge gas comprises helium and / or oxygen.

[0015] Preferably, helium is introduced into 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 5s.

[0017] Preferably, in step 3, maintaining constant pressure cleaning in the process chamber specifically includes: maintaining the introduction of cleaning gas for cleaning, maintaining the vacuum pump to evacuate air, and maintaining the pressure in the process chamber constant.

[0018] Preferably, when the purge gas is kept introduced for purge, the purge gas introduced is oxygen.

[0019] Preferably, the specific method of step-by-step controlling the continuous descent of the heating plate is:

[0020] Control the heating plate from 280mils to 500mils within 2s;

[0021] Then control the heating plate to slowly drop to 600 mils at a speed of 20 mils per second;

[0022] Finally, the heating plate is controlled to drop from 600 mils to 900 mils within 5 seconds.

[0023] According to a second aspect of the present 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, the above-mentioned TEOS chemical vapor deposition process chamber cleaning method is implemented.

[0024] According to an embodiment of the present application, the beneficial effect of using the TEOS chemical vapor deposition process chamber cleaning method is that the method does not require any equipment improvements, and only optimizes the combination of exhaust cleaning and gas extraction to greatly reduce the number of particles while discharging byproducts and residual gases, thereby ensuring product quality and cleaning effect;

[0025] This method adopts the method of first rough extraction and then fine extraction, which is more conducive to the discharge of by-products and residual gases, and can more thoroughly clean the gaps of the heating plate, pipelines and valves. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the existing technical solutions, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 The flowchart is a method for cleaning a TEOS chemical vapor deposition process chamber according to an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0029] like Figure 1 As shown, a TEOS chemical vapor deposition process chamber cleaning method in an embodiment of the present application includes the following steps:

[0030] Step 1: extracting byproducts and residual gases in the process chamber and pipeline until the first condition is reached;

[0031] In this step, the rear end of the process chamber is connected to a vacuum pump, and the front end of the process chamber is connected to input pipelines for reaction gas and purge gas. A flow regulating valve is provided on the pipeline to convert part of the gas from liquid to gas.

[0032] After the thin film is deposited, it is necessary to start the cleaning step of the process chamber, that is, to discharge the residual reaction gas and by-products. At this time, open the valve of the vacuum pump, and extract the by-products and residual gas in the process chamber and the upstream pipeline when the valve is fully opened. The first condition is set to 5s, so the vacuum pump will continue to extract for 5s before proceeding to the next step.

[0033] In other embodiments, other times or conditions may be set as the first condition according to different processes. For example, setting the pressure in the process chamber to reach a certain threshold as the first condition.

[0034] During the vapor deposition process, the temperature inside the chamber is relatively high, usually around 400°C, and the pressure inside the chamber of TEOS high-density plasma enhanced chemical vapor deposition is relatively high. Therefore, in this step, a vacuum pump is used to pre-extract some by-products and residual gases, which can reduce the pressure inside the chamber and reduce the air disturbance caused by the direct exhaust process.

[0035] Step 2: introducing a purge gas into the pipeline and the process chamber for purge until the second condition is reached;

[0036] In this step, the purge 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 residues in the pipeline and related valves. The cleaning time is 5 seconds. The flow rate of helium is controlled to 1000 sccm (1000 standard cubic centimeters per minute) through the flow control valve to purge the residues in the TEOS-related pipeline until it enters the process chamber.

[0038] Open the oxygen flow regulating valve, and introduce oxygen into other pipes except TEOS-related pipes to clean other pipes until they enter the process chamber for cleaning at the same time as helium. The cleaning time is 5s. The flow rate of oxygen is controlled by the flow control valve to be 1000sccm, i.e. 1000 standard cubic centimeters per minute. At the same time, oxygen and helium enter the process chamber separately to clean the process chamber. During the cleaning process, keep the valve of the vacuum pump fully open to facilitate the blowing of TEOS residues and by-products out of the process chamber.

[0039] In other embodiments, other times or conditions may be set as the second condition according to different processes. For example, setting the pressure in the process chamber to reach a certain threshold as the second condition.

[0040] Step 3: While maintaining constant pressure cleaning in the process chamber, control the heating plate to continue to descend in steps;

[0041] In this step, after the above steps are completed, the flow regulating valve of helium is closed, and only the flow regulating valve of oxygen is left open, and the flow rate of oxygen is maintained at 840 sccm, that is, 840 standard cubic centimeters per minute;

[0042] Adjust the valve of the vacuum pump to keep the pressure at 5 torr, gradually evacuate the air while continuing to introduce oxygen for cleaning, and keep the pressure in the process chamber constant to continuously clean each pipeline and process chamber.

[0043] The specific method of gradually evacuating air is: while the heating plate is continuously lowered into place, the valve of the vacuum pump is kept fixed to maintain the pressure until the heating plate is fully opened after it is lowered into place.

[0044] In this step, oxygen is used for cleaning, which is cheaper than helium and reduces the cleaning cost;

[0045] Moreover, helium is lighter and less effective in cleaning large particles, and heavier oxygen is more likely to remove particles;

[0046] Oxygen can undergo a reoxidation reaction with the residual TEOS and take away the TEOS residue, but it is not enough to form a photoresist material, so it will not pollute the cavity.

[0047] When oxygen is introduced, a fixed pressure is set in the process chamber, and then the position of the heating plate is controlled to drop. When the volume changes, the airflow will not change due to pressure changes, thus avoiding the lifting of more particles.

[0048] As the position of the heating plate in the process chamber drops, the volume changes. While ensuring the constant pressure in the process chamber, the heating plate drops into place, and then the angle position of the butterfly valve of the vacuum pump is controlled to change to make it fully open, thereby completely purging the butterfly valve.

[0049] The specific method of controlling the continuous descent of the heating plate in steps is:

[0050] Control the heating plate from 280mils to 500mils within 2s;

[0051] Then, the heating plate is controlled to slowly drop to 600 mils at a speed of 20 mils per second, that is, the height of the heating plate is from 500 mils to 600 mils, and is at 500 mils, 520 mils, 540 mils, 560 mils, 580 mils and 600 mils respectively, with each step taking 1 s and each step dropping 20 mils. The step-by-step lowering can reserve sufficient time to purge various parts of the heating plate drive component;

[0052] Finally, the heating plate is controlled to drop from 600 mils to 900 mils within 5 seconds and reach the final position.

[0053] The above position from 280mils to 900mils refers to the distance between the heating plate and the top sprinkler. Mils is a unit of length, equal to one thousandth of a foot. When cleaning, the heating plate needs to be lowered to the bottom to ensure that the cleaning gas can pass smoothly.

[0054] The time for the heating plate to move from the process position of 290 mils (process) to the release position of 900 mils (release position) is about 4 seconds. Since the driving part of the heating plate extends into the process chamber, there is a small gap between the driving part of the heating plate and the bottom of the process chamber. It is difficult to clean the gap after the heating plate is directly lowered into place. Therefore, in this step, a step-by-step slow lowering method is adopted to facilitate the cleaning of byproducts and residues at the gap of the driving part of the heating plate.

[0055] At the same time, the slow descent method can also reduce the disturbance of the air in the process chamber, reduce the number of particles lifted, and reduce the probability of particles reaching the wafer surface.

[0056] Step 4: Until the heating plate is in place, the vacuum pump is fully opened to make the base pressure in the process chamber reach the base pressure, complete the cleaning of the process chamber, and prepare for the processing of the next wafer.

[0057] Through the above steps, the residual gas in the process chamber is extracted in advance to reduce the pressure in the process chamber, thereby avoiding air fluctuations when the purge gas valve is opened, thereby reducing the lifting of particles caused by air disturbances; during the purge gas introduction stage, the pressure in the process chamber is always kept balanced to ensure smooth airflow in the purge pipeline and process chamber, further avoiding air disturbances; the slow descent of the heating plate can reserve enough time for cleaning the gaps, and due to the effects of the slow descent and constant pressure, no major air disturbance is caused, ensuring that the particles generated by the movement of the heating plate will be swept out under the action of the stable airflow, and will not be disturbed upward and fall on the wafer surface.

[0058] Through many tests, after using this step to deposit thin films on the wafer surface, compared with the wafer obtained by traditional chamber cleaning, the surface particles are shown in Table 1:

[0059] Table 1 Comparison of particles on PETEOS 6K film by conventional method and method of this embodiment

[0060]

[0061] It can be seen from the above table that the number of particles (0.2μm) on the film of wafers processed by the traditional method is relatively large, usually around 30 particles, and the highest can even reach 45 particles, which has a great impact on the later chip production and is not conducive to improving the qualified rate;

[0062] The wafers processed by the method in this embodiment have significantly fewer particles on the film, with only single-digit particles present. This shows that the method greatly reduces the number of particles while ensuring that the process chamber is completely cleaned, thereby helping to improve the wafer processing qualification rate.

[0063] In one embodiment of the present 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, the above-mentioned TEOS chemical vapor deposition process chamber cleaning method is implemented.

[0064] According to an embodiment of the present application, the beneficial effect of using the TEOS chemical vapor deposition process chamber cleaning method is that the method does not require any equipment improvements, and only optimizes the combination of exhaust cleaning and gas extraction to greatly reduce the number of particles while discharging byproducts and residual gases, thereby ensuring product quality and cleaning effect;

[0065] This method adopts the method of first rough extraction and then fine extraction, which is more conducive to the discharge of by-products and residual gases, and can more thoroughly clean the gaps of the heating plate, pipelines and valves.

[0066] It should be noted that the above detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present application belongs.

[0067] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0068] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0069] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. 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 explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0070] For ease of description, spatially relative terms, such as "above", "above", "on the upper surface of", "above", etc., may be used herein to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may 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 spatially relative descriptions used herein are interpreted accordingly.

[0071] In the above detailed description, reference is made to the accompanying drawings, which form a part of this document. In the accompanying drawings, similar symbols typically identify similar components unless the context indicates otherwise. The illustrated embodiments described in the detailed description, drawings, and claims are not meant 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 only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for cleaning a TEOS chemical vapor deposition process chamber, characterized in that: The steps include: Step 1: extracting byproducts and residual gases in the process chamber and pipeline until the first condition is reached; Step 2: introducing a purge gas into the pipeline and the process chamber for purge until the second condition is reached; Step 3: While maintaining constant pressure cleaning in the process chamber, control the heating plate to continue to descend in steps; Step 4: Until the heating plate is in place, the vacuum pump is fully opened to make the base pressure in the process chamber reach the base pressure, and the cleaning of the process chamber is completed.

2. The TEOS chemical vapor deposition process chamber cleaning method according to claim 1, characterized in that: In step 1, the first condition is that the air extraction time is 5 s.

3. The TEOS chemical vapor deposition process chamber cleaning method according to claim 2, characterized in that: In step 1, evacuate the air using a vacuum pump with the valve fully open.

4. The TEOS chemical vapor deposition process chamber cleaning method according to claim 2, characterized in that: In step 2, the purge gas includes helium and / or oxygen.

5. The TEOS chemical vapor deposition process chamber cleaning method according to claim 4, characterized in that: Helium is introduced into 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.

6. The TEOS chemical vapor deposition process chamber cleaning method according to claim 5, characterized in that: The second condition is that the exhaust time is 5s.

7. The TEOS chemical vapor deposition process chamber cleaning method according to claim 5, characterized in that: In step 3, maintaining constant pressure purge in the process chamber specifically includes: maintaining the introduction of purge gas for purge, maintaining the vacuum pump for evacuation, and maintaining a constant pressure in the process chamber.

8. The TEOS chemical vapor deposition process chamber cleaning method according to claim 7, characterized in that: When the purge gas is kept introduced for purge, the purge gas introduced is oxygen.

9. The TEOS chemical vapor deposition process chamber cleaning method according to claim 8, characterized in that: The specific method of controlling the continuous descent of the heating plate in steps is: Control the heating plate from 280mils to 500mils within 2s; Then control the heating plate to slowly drop to 600 mils at a speed of 20 mils per second; Finally, the heating plate is controlled to drop from 600 mils to 900 mils within 5 seconds.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the TEOS chemical vapor deposition process chamber cleaning method according to any one of claims 1 to 9 is implemented.

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