Method of plasma cleaning a substrate

Abstract

The application provides a method for cleaning a substrate by plasma, which comprises the following steps: providing a substrate to be cleaned and a plasma cleaning device, wherein the device comprises a cleaning cavity, a U-shaped track, a control module and parallel polar plates, the U-shaped track is located between the parallel polar plates; placing two ends of the substrate respectively into U-shaped slots of the U-shaped track, and the substrate is parallel to the parallel polar plates; cleaning the substrate for a preset time with preset parameters, and the control module monitors the voltage difference between the lower polar plate in the parallel polar plates and the substrate in real time, and the control module automatically adjusts the parameters when the voltage difference exceeds the preset pressure difference; after the preset time is over, detecting the surface of the substrate, and if the surface of the substrate is unqualified, repeating the steps of placing the substrate and cleaning the substrate until the surface of the substrate is qualified. The application fixes the substrate by the U-shaped slots, avoids the warping of the substrate during the cleaning process, and improves the reliability and yield of the product in combination with the control module.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of semiconductor integrated circuit manufacturing, and relates to a method for plasma cleaning a substrate. BACKGROUND

[0002] In the field of semiconductor manufacturing and electronic packaging, plasma cleaning is a common surface treatment technology, mainly used for removing contaminants on the surface of materials, improving surface activity, and performing surface modification and etching. Currently, the commonly used plasma cleaning machine mainly adopts a radio frequency power operation mode, and an upper plate and a lower plate are arranged in the cleaning cavity. The lower plate is a cathode, and the upper plate is an anode. The upper plate and the lower plate are respectively electrically connected to the two poles of the radio frequency power source. Under the action of the high-frequency power source, argon is ionized to form argon ions. These argon ions continuously impact the particles on the surface of the material under the action of the electric field, so that the flatness of the material surface is consistent. In addition, plasma cleaning can also be used for surface contaminant removal, surface activation, surface modification and etching. However, during the plasma cleaning process, due to the ionization input energy of argon and the collision of ions, the substrate material is unevenly heated, deformed, and local charge accumulation occurs, which leads to a risk of abnormal discharge (burning) due to the high local energy of the material, and the warping of the material also affects the cleaning quality and the flatness of the material surface. In particular, the track for carrying the substrate in the cleaning cavity is an L-shaped ceramic track, and the edge slot size is 1.5 mm. As shown in Figs. 1 and 2, which are respectively a partial structure diagram of the cleaning cavity and a structure diagram of the L-shaped ceramic track for carrying the material, including a plasma cleaning device 01, a cleaning cavity 011, an L-shaped ceramic track 03, a plate 04, an upper plate 041 and a lower plate 042. On this track, it is difficult to control the deformation of the substrate, and thus the distance between the substrate and the base cannot be effectively controlled, which increases the risk of abnormal discharge, resulting in poor cleaning quality of the substrate, low yield and poor flatness after cleaning. Figure 1

[0003] Therefore, it is urgent to find a method for plasma cleaning a substrate that can avoid abnormal discharge during the plasma cleaning process. SUMMARY

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a method for plasma cleaning a substrate, which solves the problems of abnormal discharge, poor cleaning quality and low yield caused by warping during the plasma cleaning process of the material in the prior art.

[0005] To achieve the above-mentioned purpose and other related purposes, the present application provides a method for plasma cleaning a substrate, comprising the following steps:

[0006] ​The application provides a substrate to be cleaned and a plasma cleaning device, the plasma cleaning device comprising a cleaning cavity, a U-shaped track, a control module and parallel plates in the cleaning cavity, the U-shaped track being located between the parallel plates and being spaced apart from a lower plate of the parallel plates by a preset distance.

[0007] The two ends of the substrate are respectively arranged in the U-shaped groove of the U-shaped track, and the substrate is parallel to the parallel plates.

[0008] The substrate is cleaned for a preset time with preset parameters, and the control module monitors the voltage difference between the lower plate and the substrate in real time, and when the voltage difference exceeds a preset pressure difference, the control module adjusts the preset parameters based on the value of the voltage difference, so that the voltage difference is within the preset pressure difference.

[0009] After the preset time, the surface flatness and cleanliness of the cleaned substrate are detected, and if the surface flatness and cleanliness of the substrate are unqualified, the above steps of placing the substrate and cleaning the substrate are repeated until the surface flatness and cleanliness of the substrate are qualified.

[0010] Optionally, the material of the U-shaped track comprises ceramic.

[0011] Optionally, the depth of the U-shaped groove ranges from 1.5mm to 2.5mm.

[0012] Optionally, the opening size of the U-shaped groove is greater than the thickness of the substrate.

[0013] Optionally, the cleaning cavity is further provided with a charge leading-out device, and the substrate on the U-shaped track is electrically connected with the charge leading-out device.

[0014] Optionally, the first preset parameters include radio frequency power, cleaning gas flow and cavity pressure of the cleaning cavity, the radio frequency power ranges from 1100W to 1300W, the cleaning gas flow ranges from 40sccm to 60sccm, and the cavity pressure of the cleaning cavity ranges from 0.8Torr to 1.2Torr.

[0015] Optionally, the cleaning gas comprises argon.

[0016] Optionally, the preset time ranges from 5min to 15min.

[0017] Optionally, the preset pressure difference ranges from -5V to 5V.

[0018] Optionally, while the control module monitors the voltage difference between the lower plate and the substrate, the control module also monitors the cavity pressure of the cleaning cavity and the distance between the substrate and the lower plate in real time.

[0019] As described above, the method for plasma cleaning substrate of the present application, by improving the track where the substrate is placed, using the U-shaped groove in the U-shaped track to hold the two ends of the substrate arranged oppositely, avoiding the substrate from being obviously warped due to uneven heating during the cleaning process, making the substrate in a relatively flat state during the cleaning process, thereby avoiding the problem of local charge accumulation in the substrate caused by the warping of the substrate, improving the cleaning quality, and facilitating the monitoring of the voltage difference between the substrate and the lower electrode plate, and then through the real-time monitoring of the voltage difference between the substrate and the lower electrode plate by the control module, when the voltage difference between the substrate and the lower electrode plate exceeds the preset pressure difference, it is convenient to timely adjust and control the cleaning parameters, further avoiding abnormal discharge during the cleaning process, improving the cleaning efficiency, improving the reliability and yield of the product, and having high industrial utilization value. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A partial structure schematic diagram of a cleaning chamber in a plasma cleaning device is shown.

[0021] Figure 2 A schematic diagram of the track in the cleaning chamber is shown.

[0022] Figure 3 A process flow chart of the method for plasma cleaning substrate of the present application is shown.

[0023] Figure 4 A structure schematic diagram of the substrate placed on the U-shaped track of the method for plasma cleaning substrate of the present application is shown.

[0024] Figure 5 A partial structure schematic diagram of the cleaning chamber of the method for plasma cleaning substrate of the present application is shown.

[0025] BRIEF DESCRIPTION OF DRAWINGS

[0026] 01 Plasma cleaning device

[0027] 011 Cleaning chamber

[0028] 02 Material

[0029] 03 L-shaped ceramic track

[0030] 04 Electrode plate

[0031] 041 Upper electrode plate

[0032] 042 Lower electrode plate

[0033] 1 Plasma cleaning device

[0034] 11 Cleaning chamber

[0035] 2 Substrate

[0036] 3 U-shaped track

[0037] 31 U-shaped groove

[0038] 4 parallel electrode plates

[0039] 41 upper electrode plate

[0040] 42 lower electrode plate DETAILED DESCRIPTION

[0041] The present application is herein described, by way of example only, with the application can be implemented or applied in other different embodiments, and the details herein can be varied as desired, without departing from the spirit of the application.

[0042] Reference will now be made to the drawings, wherein: Figures 3 to 5 It is to be understood that the drawings are to be used only for illustrative purposes and the shown drawings have not necessarily been drawn to scale. The design of the drawing merely illustrates a typical implementation of the application and therefore can not be necessarily made in real scale. Numerous changes can be made by persons skilled in the art in conjunction with the disclosure herein without departing from the scope of the application as defined by the appended claims and their equivalents.

[0043] The present embodiment provides a method for plasma cleaning a substrate, as shown in Figure 3 FIG. 1 is a flow chart of a method for plasma cleaning a substrate, including the following steps:

[0044] S1: providing a substrate to be cleaned and a plasma cleaning apparatus, the plasma cleaning apparatus including a cleaning chamber, a U-shaped track, a control module, and parallel electrode plates in the cleaning chamber, the U-shaped track being located between the parallel electrode plates and spaced apart from a lower electrode plate of the parallel electrode plates by a predetermined distance;

[0045] S2: placing two ends of the substrate respectively in U-shaped grooves of the U-shaped track, the substrate being parallel to the parallel electrode plates;

[0046] S3: cleaning the substrate with predetermined parameters for a predetermined time, while the control module monitors a voltage difference between the lower electrode plate and the substrate in real time, and when the voltage difference exceeds a predetermined pressure difference, the control module adjusts the predetermined parameters based on the value of the voltage difference to make the voltage difference within the predetermined pressure difference;

[0047] S4: after the preset time ends, the flatness and cleanliness of the cleaned substrate are detected, and if the flatness and cleanliness of the substrate are unqualified, the steps of placing the substrate and cleaning the substrate are repeated until the flatness and cleanliness of the substrate are qualified.

[0048] Referring to Figures 4 to 5 , steps S1 and S2 are performed: a substrate 2 to be cleaned and a plasma cleaning device 1 are provided, the plasma cleaning device 1 includes a cleaning chamber 11, a U-shaped track 3, a control module, and parallel plates 4 in the cleaning chamber 11, the U-shaped track 3 is located between the parallel plates 4 and is spaced apart from the lower plate 42 of the parallel plates 4 by a preset distance; the two ends of the substrate 2 are respectively placed in the U-shaped groove 31 of the U-shaped track 3, and the substrate 2 is parallel to the parallel plates 4.

[0049] Specifically, the plasma cleaning device 1 is a commonly used online plasma cleaning machine, which will not be described here.

[0050] Specifically, as shown in Figure 5 , it is a partial structure diagram of the cleaning chamber 11, the cleaning chamber 11 is a process chamber for cleaning the substrate 2 to be cleaned, and the material and size of the cavity wall can be selected according to the actual needs of the plasma cleaning process.

[0051] Specifically, the plasma cleaning device 1 also has a transmission mechanism, before cleaning, the transmission mechanism is used to convey the substrate 2 to be cleaned into the cleaning chamber 11 and place it on the U-shaped track 3, so that when the cleaning chamber 11 reaches the condition of cleaning the substrate 2, the substrate 2 is plasma cleaned; after cleaning, the transmission mechanism is used to convey the cleaned substrate 2 out of the cleaning chamber 11.

[0052] Specifically, the control module is used to control the operation of the plasma cleaning device 1 and adjust the process parameters of the plasma cleaning process, and monitor the operation state of the plasma cleaning device 1 and the state of the substrate 2 during cleaning.

[0053] Specifically, the control module can be composed of an external mechanical control structure and an external electronic control unit, or only an external electronic control unit can be used for control, and in the case of ensuring normal operation of the equipment and facilitating operation of the operator, the position of the control module in the plasma cleaning device 1 can be set according to the actual situation.

[0054] Specifically, the parallel plates 4 include an upper plate 41 and a lower plate 42, which are electrically connected to the anode and cathode of the RF power supply, respectively. The high-frequency voltage is used to cause the cleaning gas between the upper plate 41 and the lower plate 42 to break down at low pressure, ionizing the gas through glow discharge and generating plasma. In this embodiment, the upper plate 41 is located below the top wall of the cleaning chamber 11 and electrically connected to the anode of the RF power supply. The upper plate 41 is separated from the top wall of the cleaning chamber 11 by a predetermined distance. The lower plate 42 is located above the bottom wall of the cleaning chamber 11 and electrically connected to the cathode of the RF power supply. The lower plate 42 is separated from the bottom wall of the cleaning chamber 11 by a predetermined distance.

[0055] Specifically, while ensuring the cleaning effect of the substrate 2, the size and shape of the upper plate 41 and the lower plate 42 can be selected based on actual conditions, the distance between the upper plate 41 and the lower plate 42 can be selected based on actual conditions, and the power and frequency range of the radio frequency power supply electrically connected to the upper plate 41 and the lower plate 42 can be selected according to actual conditions.

[0056] Specifically, such as Figure 4 As shown, it is a structural schematic diagram after the substrate 2 is placed on the U-shaped track 3. The U-shaped track 3 is used to support the substrate 2. The U-shaped track 3 includes at least two oppositely arranged U-shaped grooves 31, and the openings of the U-shaped grooves 31 are oppositely arranged to facilitate clamping the two oppositely arranged ends of the substrate 2.

[0057] As an example, the material of the U-shaped track 3 includes ceramic or other high temperature resistant rigid insulating materials. In this embodiment, two ceramic U-shaped grooves parallel to the lower plate 42 are used as the U-shaped track 3.

[0058] As an example, the depth range of the U-shaped groove 31 is 1.5mm to 2.5mm, that is, the distance between the opening of the U-shaped groove 31 and the U-shaped bottom surface of the U-shaped groove 31 is 1.5mm to 2.5mm. For example, the depth of the U-shaped groove 31 can be 1.5mm, 1.8mm, 2mm, 2.3mm, or 2.5mm. Preferably, the depth of the U-shaped groove 31 is 2mm, so that the U-shaped rail 3 is suitable for carrying substrates 2 of various sizes.

[0059] As an example, the opening size of the U-shaped groove 31 is larger than the thickness of the substrate 2, that is, the distance between the upper and lower walls of the U-shaped groove 31 is larger than the thickness of the substrate 2, so as to facilitate the insertion of the substrate 2 into the U-shaped groove 31 while avoiding damage to the substrate 2 during the insertion process of the substrate 2 into the U-shaped groove 31.

[0060] Specifically, the method for placing the two opposite ends of the substrate 2 in the opposite U-shaped grooves 31 of the U-shaped track 3 can be that the transmission mechanism inserts the substrate 2 into the two U-shaped grooves 31 from the openings on the sides of the U-shaped track 3 .

[0061] Specifically, the distance between the substrate 2 and the lower electrode plate 42 can be selected according to actual conditions without limitation.

[0062] As an example, the cleaning chamber 11 is also provided with a charge leading-out device, and the substrate 2 on the U-shaped track 3 is electrically connected to the charge leading-out device.

[0063] Specifically, the charge leading-out device is used to lead out the charge in the substrate 2, and when the substrate 2 is placed on the U-shaped track 3 in the cleaning chamber 11, the substrate 2 is electrically connected to the charge leading-out device in the cleaning chamber 11 to avoid excessive charge accumulation in the substrate 2 during the process of plasma cleaning the substrate 2, which may cause abnormal discharge.

[0064] Specifically, steps S3 and S4 are performed: the substrate 2 is cleaned for a preset time with preset parameters, and the control module monitors the voltage difference between the lower electrode plate 42 and the substrate 2 in real time, and when the voltage difference exceeds the preset pressure difference, the control module adjusts the preset parameters based on the value of the voltage difference to make the voltage difference within the preset pressure difference; after the preset time is up, the surface flatness and cleanliness of the cleaned substrate 2 are detected, and if the surface flatness and cleanliness of the substrate 2 are unqualified, the above steps of placing the substrate 2 and cleaning the substrate 2 are repeated until the surface flatness and cleanliness of the substrate 2 are qualified.

[0065] As an example, the first preset parameters include radio frequency power, cleaning gas flow, and chamber pressure of the cleaning chamber 11, the radio frequency power ranges from 1100W to 1300W, the cleaning gas flow ranges from 40sccm to 60sccm, and the chamber pressure of the cleaning chamber 11 ranges from 0.8Torr to 1.2Torr, for example, the radio frequency power can be 1100W, 1200W, 1300W, the cleaning gas flow can be 40sccm, 45sccm, 50sccm, 55sccm, 60sccm, and the chamber pressure of the cleaning chamber 11 can be 0.8Torr, 0.9Torr, 1.0Torr, 1.1Torr, 1.2Torr. Preferably, the radio frequency power is 1200W, the cleaning gas flow is 50sccm, and the chamber pressure of the cleaning chamber 11 is 1.0Torr.

[0066] Specifically, after the substrate 2 is placed at a preset position above the lower electrode plate 42, before the cleaning gas is introduced into the cleaning chamber 11, the cleaning chamber 11 is also subjected to a vacuumizing step to discharge impurity gas in the cleaning chamber 11, and the vacuum degree value of the vacuumized cleaning chamber 11 can be selected according to actual conditions without affecting the cleaning of the substrate 2 by the residual gas in the cleaning chamber 11.

[0067] Specifically, after the cleaning cavity 11 is vacuumized, the cleaning gas is introduced into the cleaning cavity 11 to fill the entire cleaning cavity 11 before the substrate 2 is cleaned, so that the cleaning gas can be ionized and form plasma under certain conditions.

[0068] For example, the cleaning gas includes argon, and can also be other suitable gases, such as oxygen, hydrogen, etc. In this embodiment, argon is used as the main component of the cleaning gas.

[0069] Specifically, by adjusting the flow rate of the cleaning gas, the radio frequency power, and the pressure in the cleaning cavity 11, the concentration of the cleaning gas in the cleaning cavity 11, the pressure in the cleaning cavity 11, and the radio frequency power applied between the parallel plates 4 are adjusted to a condition that can break down the cleaning gas between the parallel plates 4, so that the cleaning gas can be ionized and form plasma. The plasma is accelerated under the action of the voltage between the parallel plates 4 and hits the surface of the substrate 2, thereby cleaning the surface of the substrate 2.

[0070] Specifically, during the plasma cleaning process, the ionization of the cleaning gas is accompanied by the input of energy, and the collision of particles in the cleaning cavity 11 with the inner wall of the cleaning cavity 11 and the process of cleaning the substrate 2 also generates heat, resulting in uneven heat distribution in the cleaning cavity 11, uneven heating of the substrate 2, and warping of the substrate 2. By inserting the two ends of the oppositely arranged substrate 2 into the U-shaped groove 31 from the opening of the U-shaped groove 31, when the substrate 2 warps, the U-shaped groove 31 can hold the substrate 2 to prevent further warping of the substrate 2 due to uneven heating. The distance between the substrate 2 and the lower plate 42 is controlled by the mechanical structure of the track to prevent the substrate 2 from warping too much, which can cause uneven distribution of charges in the substrate 2, excessive accumulation of charges in a local area, and abnormal discharge during the cleaning process.

[0071] Specifically, the substrate 2 is spaced apart from the lower plate 42 by a predetermined distance, and the voltage difference between the lower plate 42 and the substrate 2 is monitored in real time by the control module. The voltage difference value obtained by real-time monitoring can be used to adjust the cleaning parameters during the cleaning process of the substrate 2 to prevent excessive voltage between the substrate 2 and the lower plate 42 due to the accumulation of charges in the substrate 2.

[0072] For example, the preset pressure difference range is -5V-5V, i.e., the voltage difference between the substrate 2 and the lower plate 42 is in the range of -5V-5V. Due to the different voltage resistance of the substrate 2, the material of the substrate 2, and the distance between the substrate 2 and the lower plate 42, the pressure difference between the substrate 2 and the lower plate 42 also changes accordingly. Therefore, the voltage difference between the substrate 2 and the lower plate 42 can also be in other ranges, such as -1V-1V, -2V-2V, or other pressure difference ranges according to actual cleaning needs.

[0073] Specifically, when the control module monitors that the voltage difference between the substrate 2 and the lower electrode plate 42 exceeds the preset voltage difference range, the preset parameters are automatically adjusted based on the value exceeding the preset voltage difference range, so as to regulate the voltage difference between the substrate 2 and the lower electrode plate 42, so that the voltage difference between the substrate 2 and the lower electrode plate 42 is within the preset voltage difference range. For example, the distance between the substrate 2 and the lower electrode plate 42, the flow of the cleaning gas, the radio frequency power, and the internal pressure of the cleaning chamber 11 can be adjusted according to the voltage difference between the substrate 2 and the lower electrode plate 42. Any two or all four of the distance between the substrate 2 and the lower electrode plate 42, the flow of the cleaning gas, the radio frequency power, and the internal pressure of the cleaning chamber 11 can be adjusted. During the adjustment, other parameters in the plasma cleaning device 1 can also be adjusted synchronously.

[0074] For example, while monitoring the voltage difference between the lower electrode plate 42 and the substrate 2, the control module also monitors the internal pressure of the cleaning chamber 11 and the distance between the substrate 2 and the lower electrode plate 42 in real time. When the voltage difference between the substrate 2 and the lower electrode plate 42 exceeds the preset voltage difference range, the control module adjusts the cleaning parameters based on the corresponding voltage difference exceeding value and the state of the substrate 2.

[0075] Specifically, through real-time monitoring of the cleaning process by the control module and automatic real-time adjustment of the cleaning parameters based on the monitoring results, the safety of the substrate 2 during the cleaning process is ensured.

[0076] For example, the preset time range is 5-15 minutes, i.e. the time range for cleaning the substrate 2 carried on the U-shaped track 3 in the cleaning chamber 11 is 5-15 minutes, for example, 5 minutes, 8 minutes, 10 minutes, 12 minutes, or 15 minutes. Preferably, the time for cleaning the substrate 2 carried on the U-shaped track 3 in the cleaning chamber 11 is 10 minutes, so as to ensure that the plasma has enough time to clean and smooth the surface of the substrate 2, while avoiding excessive cleaning time and damaging the substrate 2.

[0077] Specifically, after the preset time ends, the substrate 2 is transported out by the transmission mechanism, and the flatness and cleanliness of the surface of the substrate 2 are detected to ensure that the cleaning effect meets the standard.

[0078] Specifically, since the plasma cleaning process has etching effect while cleaning the surface of the substrate 2, when the surface cleanliness and flatness of the cleaned substrate 2 are detected to be unqualified and re-cleaning is performed, the parameter values in the preset parameters can be different from those in the initial cleaning, and the parameter values in the preset parameters for re-cleaning can be adjusted according to the flatness and cleanliness of the surface of the substrate 2. For example, when the cleanliness of the surface of the substrate 2 is unqualified, the RF power can be appropriately reduced according to the cleanliness, compared with the preset parameters in the previous cleaning, to reduce the intensity of the plasma impacting the surface of the substrate 2, and the cleaning time for re-cleaning can be appropriately reduced to reduce the damage to the surface of the substrate 2 caused by re-cleaning. When the flatness of the surface of the substrate 2 is unqualified, the RF power can be appropriately increased, compared with the preset parameters in the previous cleaning, to increase the intensity of the plasma impacting the surface of the substrate 2, and the cleaning time for re-cleaning can be appropriately reduced to reduce the damage to the surface of the substrate 2 caused by re-cleaning.

[0079] Specifically, by setting the track carrying the substrate 2 in the cleaning cavity 11 as a U-shaped track 3, when the substrate 2 is unevenly heated during cleaning, causing local deformation of the substrate 2, and then causing the substrate 2 to warp, due to the limitation of the U-shaped groove 31, the substrate 2 is difficult to deform significantly, thereby ensuring the stability of the distance between the substrate 2 and the lower electrode plate 42, and avoiding the phenomenon of local charge accumulation caused by deformation of the substrate 2, thereby avoiding the problem of abnormal discharge of the substrate 2 during cleaning caused by warping of the substrate 2.

[0080] Specifically, during the cleaning of the substrate 2, the control module monitors the voltage difference between the substrate 2 and the lower electrode plate 42, the distance between the substrate 2 and the lower electrode plate 42, and the pressure in the cleaning cavity 11 in real time, and based on the real-time data of the voltage difference, the distance between the substrate 2 and the lower electrode plate 42, and the pressure in the cleaning cavity 11, the cleaning parameters are dynamically adjusted in real time, so that the cleaning process of the substrate 2 is efficient and stable, the quality and reliability of the product are improved, the quality of the operation and the yield of the product are improved, and the production cost is reduced.

[0081] The method for cleaning the substrate by plasma of the embodiment utilizes the U-shaped groove 31 in the U-shaped track 3 to hold the substrate 2, avoids the substrate 2 from being unevenly heated during the cleaning process to generate obvious warping, and then avoids the uneven distribution of the electric charge in the substrate 2 caused by the warping of the substrate 2, the electric charge aggregation in some areas, the abnormal discharge of the substrate 2 during the cleaning process of the substrate 2, and the like, and makes the substrate 2 in a relatively flat state for cleaning, improves the cleaning quality, and facilitates monitoring the voltage difference between the substrate 2 and the lower electrode plate 42.

[0082] In summary, the method for cleaning the substrate by plasma of the embodiment changes the track for carrying the substrate to the U-shaped track including the U-shaped groove, holds the substrate by the U-shaped groove at the two relatively arranged ends of the substrate, avoids the obvious warping of the substrate caused by the uneven heating of the substrate during the cleaning process, avoids the problem of the local aggregation of the electric charge in the substrate caused by the warping of the substrate during the cleaning process, makes the substrate in a relatively flat state during the cleaning process, improves the cleaning quality, facilitates monitoring the voltage difference between the substrate and the lower electrode plate, and the like, controls the voltage difference between the substrate and the lower electrode plate by the control module in real time, adjusts the cleaning parameters in time when the voltage difference between the substrate and the lower electrode plate exceeds the preset pressure difference, further avoids the abnormal discharge during the cleaning process, improves the cleaning efficiency, improves the reliability and yield of the product, and the like. Therefore, the method for cleaning the substrate by plasma of the embodiment effectively overcomes the various shortcomings in the prior art and has a high industrial utilization value.

[0083] The above embodiments only exemplarily illustrate the principles and effects of the method for cleaning the substrate by plasma of the embodiment, and are not used to limit the method for cleaning the substrate by plasma of the embodiment. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the method for cleaning the substrate by plasma of the embodiment. Therefore, all equivalent modifications or changes completed by any person skilled in the art without departing from the spirit and technical thought of the method for cleaning the substrate by plasma of the embodiment should be covered by the claims of the method for cleaning the substrate by plasma of the embodiment.

Claims

1. A method of plasma cleaning a substrate, the method comprising: The method comprises the following steps: Providing a substrate to be cleaned and a plasma cleaning device, the plasma cleaning device comprising a cleaning chamber, a U-shaped track, a control module and parallel plates in the cleaning chamber, the U-shaped track being located between the parallel plates and spaced apart from a lower plate of the parallel plates by a preset distance; Placing two ends of the substrate opposite to each other in U-shaped grooves of the U-shaped track respectively, the substrate being parallel to the parallel plates; Cleaning the substrate with preset parameters for a preset time, while the control module monitors a voltage difference between the lower plate and the substrate in real time, and when the voltage difference exceeds a preset pressure difference, the control module adjusts the preset parameters based on the value of the voltage difference to make the voltage difference within the preset pressure difference; After the preset time, detecting the surface flatness and cleanliness of the cleaned substrate, and if the surface flatness and cleanliness of the substrate are unqualified, repeating the steps of placing the substrate and cleaning the substrate until the surface flatness and cleanliness of the substrate are qualified.

2. The method of claim 1, wherein: The material of the U-shaped track comprises ceramic.

3. The method of claim 1, wherein: The depth of the U-shaped groove ranges from 1.5 mm to 2.5 mm.

4. The method of claim 1, wherein: The opening size of the U-shaped groove is greater than the thickness of the substrate.

5. The method of claim 1, wherein: The cleaning chamber is also provided with a charge leading-out device, and the substrate on the U-shaped track is electrically connected to the charge leading-out device.

6. The method of claim 1, wherein: The preset parameters include radio frequency power, cleaning gas flow and chamber pressure of the cleaning chamber, the radio frequency power ranges from 1100 W to 1300 W, the cleaning gas flow ranges from 40 sccm to 60 sccm, and the chamber pressure of the cleaning chamber ranges from 0.8 Torr to 1.2 Torr.

7. The method of claim 6, wherein: The cleaning gas comprises argon.

8. The method of claim 1, wherein: The preset time ranges from 5 min to 15 min.

9. The method of claim 1, wherein: The preset pressure difference ranges from -5 V to 5 V.

10. The method of claim 1, wherein: While the control module monitors the voltage difference between the lower plate and the substrate, the control module also monitors the chamber pressure of the cleaning chamber and the distance between the substrate and the lower plate in real time.

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