Deposition system and wafer position monitoring method

Abstract

The invention discloses a deposition system and a wafer monitoring method. The deposition system comprises a main body, a heater, a spraying plate, a direct-current voltage module, a detection module and a radio frequency source module. A process cavity is formed in the main body. The heater is arranged in the process cavity, and the heater is used for bearing a wafer. The spraying plate is installed on the main body, one face of the spraying plate is opposite to the heater, and the space between the heater and the spraying plate is used for containing process gas. The direct-current voltage module is connected to one of the spraying plate and the heater and used for applying direct-current voltage. The detection module is connected to the other one of the spraying plate and the heater and used for detecting electrical parameters between the spraying plate and the heater. The radio frequency source module is connected to the spraying plate and used for applying a radio frequency field in the process cavity. In this way, whether the position of the wafer is abnormal or not can be detected.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a deposition system and a wafer position monitoring method. Background Art

[0002] In the related technology, a robot is usually used to transfer the wafer into the process chamber, and the operator uses the position sensor data of the robot to determine whether the wafer is in the center of the heater. After the wafer is transferred into the process chamber, it may not fall into the center of the heater, resulting in abnormal back plating, causing the wafer to continue the subsequent process, resulting in a waste of time and cost. Summary of the invention

[0003] The embodiments of the present application provide a deposition system and a wafer position monitoring method, which can detect whether the position of the wafer is abnormal.

[0004] In a first aspect, an embodiment of the present application provides a deposition system. The deposition system includes a main body, a heater, a spray plate, a DC voltage module, a detection module and a radio frequency source module. A process chamber is formed inside the main body. The heater is arranged in the process chamber, and the heater is used to carry a wafer. The spray plate is installed on the main body, one side of the spray plate is arranged opposite to the heater, and the space between the heater and the spray plate is used to accommodate process gas. The DC voltage module is connected to one of the spray plate and the heater, and is used to apply a DC voltage. The detection module is connected to the other of the spray plate and the heater, and is used to detect electrical parameters between the spray plate and the heater. The radio frequency source module is connected to the spray plate, and is used to apply a radio frequency field in the process chamber.

[0005] Optionally, the detection module is a voltage detection module, one end of the voltage detection module is electrically connected to the spray plate, and the other end is electrically connected to the DC voltage module; one end of the DC voltage module is electrically connected to the heater, and the other end is electrically connected to the voltage detection module.

[0006] Optionally, the voltage detection module includes a detection resistor and a detection probe, and the detection resistor and the detection probe are connected in parallel to form the voltage detection module.

[0007] Optionally, one end of the DC voltage module is electrically connected to the heater, and the other end is grounded.

[0008] Optionally, the detection module is a voltage detection module, which includes a detection resistor and a detection probe, one end of the detection resistor is electrically connected to the spray plate, and the other end is grounded.

[0009] Optionally, one end of the detection probe is electrically connected between the detection resistor and the shower plate, and the other end is grounded.

[0010] Optionally, the heater and the shower plate are connected to each other through the process chamber and the wafer.

[0011] Optionally, the deposition system further comprises a bellows, which is sleeved around the outer circumference of the heater, and the heater is movably connected to the main body.

[0012] Optionally, the RF source module includes an AC power supply and a matcher, the AC power supply and the matcher are connected in series, one end of the AC power supply is grounded, and one end of the matcher is electrically connected to the spray plate.

[0013] In a second aspect, the present application provides a wafer position monitoring method. The method adopts the above-mentioned deposition system. The steps include:

[0014] The electrical parameters between the heater and the spray plate are obtained through the detection module;

[0015] comparing electrical parameters with preset parameters;

[0016] If the electrical parameters match the preset parameters, it is determined that the wafer placement in the deposition system is normal and the process flow continues;

[0017] If the electrical parameters do not match the preset parameters, it is determined that the wafer placement in the deposition system is abnormal and the process flow is suspended.

[0018] The beneficial effects of the present application are: different from the prior art, the heater can carry and heat the wafer, and the spray plate can introduce process gas to the heater. The DC voltage module can apply a positive voltage or a negative voltage to one of the heater or the spray plate. The DC voltage module can form a detection loop with the detection module to detect the electrical parameters between the spray plate and the heater. Due to the difference in the distribution of ionized process gas in the process chamber between normal and abnormal wafer placement. Based on this, the electrical parameters between the spray plate and the heater will differ due to the placement of the wafer. In this way, by detecting the electrical parameters through the detection module, it is possible to monitor whether the wafer is placed normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of an embodiment of a deposition system of the present application;

[0020] Figure 2 is a schematic diagram of another embodiment of the deposition system of the present application;

[0021] Figure 3 It is a schematic diagram of the normal mode of deposition of wafers in the present application system;

[0022] Figure 4 is a schematic diagram of abnormal placement of wafers in the deposition system of the present application;

[0023] Figure 5 It is a flow chart of the wafer position monitoring method of the present application.

[0024] Reference numerals:

[0025] Deposition system, 1; main body, 11; process chamber, 111; heater, 12; shower plate, 13; DC voltage module, 14; detection module, 15; detection resistor, 151; detection probe, 152; RF source module, 16; AC power supply, 161; matcher, 162; bellows, 17.

[0026] Wafer, 20. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. 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 this field without creative work are within the scope of protection of this application.

[0028] In the related art, a robot is usually used to transfer the wafer into the process chamber, and the operator uses the position sensor data of the robot to judge whether the wafer is in the center of the heating plate based on experience. In some cases, the heating plate is provided with a groove to accommodate the wafer. If the wafer is not in the center of the heating plate, it is easy to cause problems with the side wall of the wafer and the groove. In this case, there is no wafer position monitoring device after the wafer is transferred into the process chamber. When the wafer fails to fall to the center of the wafer, abnormal back plating occurs without prompt information, causing the wafer to continue the subsequent process, resulting in a waste of work time and cost. In order to improve the above technical problems, the present application can provide the following embodiments.

[0029] Combination Figures 1 to 4 , an embodiment of the present application provides a deposition system 1. The deposition system 1 includes a main body 11, a heater 12, a shower plate 13, a DC voltage module 14, a detection module 15 and a radio frequency source module 16. A process chamber 111 is formed inside the main body 11. The process chamber 111 can accommodate the heater 12 and the wafer 20, and can allow process gas to pass through. The process gas in the process chamber 111 will be ionized under the action of the radio frequency field, thereby achieving film coating on the wafer 20.

[0030] The heater 12 is disposed in the process chamber 111 . The heater 12 can carry the wafer 20 and heat the wafer 20 so that the temperature of the wafer 20 can meet the conditions required by the coating process. Optionally, the heater 12 is provided with a groove for accommodating the wafer 20 .

[0031] In some embodiments, the deposition system 1 further includes a bellows 17, which is sleeved around the outer periphery of the heater 12, and the heater 12 is movably connected to the main body 11. The heater 12 can move up and down, thereby achieving the purpose of moving the wafer 20. During the up and down movement of the heater 12, the bellows 17 can follow the movement of the heater 12 to expand and contract, thereby ensuring the airtightness of the process chamber 111 during the movement of the heater 12.

[0032] The shower plate 13 is mounted on the main body 11, and one side of the shower plate 13 is disposed opposite to the heater 12. The shower plate 13 can uniformly introduce the process gas into the process chamber 111. The space between the heater 12 and the shower plate 13 is used to accommodate the process gas.

[0033] The RF source module 16 is connected to the shower plate 13, and is used to apply a RF field in the process chamber 111. Under the action of the RF source module 16, a RF field can be generated in the process chamber 111, thereby ionizing the process gas.

[0034] Combination Figure 1 In some embodiments, the RF source module 16 includes an AC power supply 161 and a matcher 162, the AC power supply 161 and the matcher 162 are connected in series, one end of the AC power supply 161 is grounded, and one end of the matcher 162 is electrically connected to the shower plate 13. The AC power supply 161 can form a RF field in the process chamber 111 through the matcher 162.

[0035] The DC voltage module 14 is connected to one of the shower plate 13 and the heater 12 for applying a DC voltage. The detection module 15 is connected to the other of the shower plate 13 and the heater 12 for detecting electrical parameters between the shower plate 13 and the heater 12 .

[0036] In some embodiments, the DC voltage module 14 is connected to the heater 12. In this case, in addition to being used to detect the position of the wafer 20, the DC voltage module 14 can also make the heater 12 have polarity, so as to adsorb the wafer 20. In some cases, the technical solution proposed in this application can use the original functional module of the deposition system 1 for adsorbing the wafer 20 to play the role of the DC voltage module 14 to perform the aforementioned wafer 20 position detection.

[0037] In some embodiments, the heater 12 and the shower plate 13 are connected through the process chamber 111 and the wafer 20. In the technical solution provided in the present application, it is necessary to detect the electrical parameters between the heater 12 and the shower plate 13. And the detection module 15 and the voltage module are respectively connected to the shower plate 13 and the heater 12. Therefore, it is necessary to avoid a short circuit between the shower plate 13 and the heater 12. In addition to forming a detection loop with the detection module 15 and the DC voltage module 14, the heater 12 and the shower plate 13 need to be connected through the process chamber 111 and the wafer 20 to accurately detect the electrical parameters between the heater 12 and the shower plate 13.

[0038] The DC voltage module 14 can apply a positive voltage or a negative voltage to one of the heater 12 or the shower plate 13. The DC voltage module 14 can form a detection circuit with the detection module 15 to detect the electrical parameters between the shower plate 13 and the heater 12. Since the distribution of the ionized process gas in the process chamber 111 will be different when the wafer 20 is placed normally or abnormally. Based on this, the electrical parameters between the shower plate 13 and the heater 12 will be different due to the placement of the wafer 20. In this way, by detecting the electrical parameters through the detection module 15, it is possible to monitor whether the wafer 20 is placed normally.

[0039] The following is a detailed description of the detection of whether the wafer 20 is placed normally. The AC power supply 161 of the RF source module 16 can generate a high-frequency AC signal, which is transmitted to the shower plate 13 via the matcher 162. The gas in the process chamber 111 is excited by the high-frequency electromagnetic field to form plasma. Figure 3 When the position of the wafer 20 is normal, the wafer 20 and the heater 12 are in close contact, and the plasma only exists above the wafer 20. In this case, the DC signal generated by the DC voltage module 14 passes through the heater 12 and the wafer 20, then penetrates the plasma into the shower plate 13, and then passes through the detection module 15. The detection module 15 can detect a normal electrical parameter at this time. It should be noted that the normal electrical parameter can be determined according to the specific deposition system 1, and the specific range of the normal electrical parameter is not limited here.

[0040] Furthermore, combined with Figure 4 When the position of the wafer 20 is abnormal, a gap will be generated between the wafer 20 and the heater 12, and the plasma will diffuse into the gap and partially contact the heater 12, for example Figure 4In the area indicated by the dotted line, there will be plasma. In this case, part of the DC signal can enter the shower plate 13 with the help of plasma after passing through the heating plate, and the resistance of the wafer 20 is partially short-circuited, and the total resistance formed by the wafer 20 and the heater 12 is reduced. In this case, the electrical parameters detected by the detection module 15 will have a difference compared with the normal electrical parameters. By judging the electrical parameters detected by the detection module 15, it is possible to determine whether the placement of the wafer 20 is abnormal, thereby reducing the situation of abnormal back plating of the wafer 20 and saving time and cost.

[0041] In some embodiments, the detection module 15 is a voltage detection module 15, and the detection module 15 can directly or indirectly detect the voltage between the heater 12 and the spray plate 13. One end of the voltage detection module 15 is electrically connected to the spray plate 13, and the other end is electrically connected to the DC voltage module 14. One end of the DC voltage module 14 is electrically connected to the heater 12, and the other end is electrically connected to the voltage detection module 15. In the above manner, a detection loop can be formed, so that the voltage between the heater 12 and the spray plate 13 can be directly or indirectly detected.

[0042] In some embodiments, in combination Figure 2 , the voltage detection module 15 includes a detection resistor 151 and a detection probe 152, and the detection resistor 151 and the detection probe 152 are connected in parallel to form the voltage detection module 15. Among them, the detection resistor 151 is connected in series with the spray plate 13 and the heater 12. The resistance between the spray plate 13 and the heater 12 is also connected in series with the detection resistor 151. In the entire detection loop, when the voltage between the spray plate 13 and the heater 12 decreases, the voltage of the detection resistor 151 will increase. By monitoring the voltage of the detection resistor 151 through the detection probe 152, the voltage between the spray plate 13 and the heater 12 can be indirectly reflected, so as to achieve the aforementioned function of determining whether the wafer 20 is placed abnormally.

[0043] In some other embodiments, one end of the DC voltage module 14 is electrically connected to the heater 12 , and the other end is grounded. The DC voltage module 14 can apply voltage to the heater 12 .

[0044] Furthermore, combined with Figure 1 The voltage detection module 15 includes a detection resistor 151 and a detection probe 152, the detection resistor 151 and the detection probe 152 are connected in parallel, one end of the detection resistor 151 is electrically connected to the spray plate 13, and the other end is grounded. Optionally, one end of the detection probe 152 is electrically connected between the detection resistor 151 and the spray plate 13, and the other end is grounded. By grounding the DC voltage module 14, the detection resistor 151, and the detection probe 152, a loop for parameter detection between the spray plate 13 and the heater 12 can be formed.

[0045] The detection resistor 151 is connected in series with the shower plate 13 and the heater 12. The resistance between the shower plate 13 and the heater 12 is also connected in series with the detection resistor 151. In the entire detection loop, when the voltage between the shower plate 13 and the heater 12 decreases, the voltage of the detection resistor 151 increases. By monitoring the voltage of the detection resistor 151 through the detection probe 152, the voltage between the shower plate 13 and the heater 12 can be indirectly reflected, so as to achieve the aforementioned function of determining whether the wafer 20 is placed abnormally.

[0046] The DC voltage module 14, the detection resistor 151 and the detection probe 152 are grounded at the same potential. By grounding the DC voltage module 14, the detection resistor 151 and the detection probe 152, the wiring of each module does not need to be directly connected to each other. For the deposition system 1, the length of the wiring can be reduced, thereby reducing the influence of the wiring resistance on the detection result.

[0047] Combination Figure 5 The present application provides a method for monitoring the position of a wafer 20. The method uses the aforementioned deposition system 1. The steps include:

[0048] S10: Introduce detection gas into the process chamber 111.

[0049] Among them, the detection gas can be a gas that does not produce a coating reaction with the wafer 20 after ionization, so that the wafer 20 will not be subjected to a coating process during the position detection process of the wafer 20, thereby reducing abnormal coating of the wafer 20 caused by gas ionization when the wafer 20 is placed abnormally, thereby reducing the waste of the wafer 20.

[0050] In other embodiments, the detection gas may also be a gas required for the coating process, and the wafer 20 may be coated while the position of the wafer 20 is detected. In this case, the wafer 20 that is detected abnormally and has been coated may be marked to distinguish it from the wafer 20 that is normally coated.

[0051] The type of detection gas may be determined based on the cost of the production process and the production schedule, and based on cost considerations from different angles, it may be considered to use a gas that can coat the wafer 20 or a gas that cannot coat the wafer 20 .

[0052] S20: Ionize the detection gas.

[0053] After the gas is introduced, the RF source module 16 can be started to ionize the detection gas, and the ionized plasma can conduct electricity in the process chamber 111. If the wafer 20 is placed abnormally, the plasma will enter the gap between the wafer 20 and the heater 12, resulting in a decrease in the total resistance. Based on the above characteristics, the position of the wafer 20 can be detected in the following way.

[0054] S30: Acquire the electrical parameters between the heater 12 and the shower plate 13 through the detection module 15.

[0055] The deposition system 1 of the present application can directly or indirectly detect the electrical parameters between the heater 12 and the shower plate 13 through the detection module 15 .

[0056] S40: Compare the electrical parameters with the preset parameters.

[0057] For the deposition system 1, if the wafer 20 is placed normally, the path of the electrical signal of the DC voltage module 14 will not change much. Therefore, the normal range of electrical parameters between the shower plate 13 and the heater 12 can be measured when the wafer 20 is placed normally, and this can be used as a judgment standard.

[0058] S50: If the electrical parameters match the preset parameters, it is determined that the wafer 20 in the deposition system 1 is placed normally, and the process flow continues.

[0059] When the position of the wafer 20 is normal, the wafer 20 and the heater 12 are in close contact, and the plasma only exists above the wafer 20. In this case, the DC signal generated by the DC voltage module 14 passes through the heater 12 and the wafer 20, then penetrates the plasma into the shower plate 13, and then passes through the detection module 15. The detection module 15 can detect an electrical parameter at this time, and the electrical parameter matches the preset parameter. Therefore, when the parameters match, it can be considered that the wafer 20 is placed normally. In some cases, the duration for which the electrical parameters remain normal can also be detected. If the time for which the electrical parameters remain normal is greater than the preset threshold, it can be confirmed whether the wafer 20 is placed normally. This method can reduce the possibility of misjudgment when, for example, the plasma does not fully enter between the wafer 20 and the heater 12.

[0060] S60: If the electrical parameters do not match the preset parameters, it is determined that the placement of the wafer 20 in the deposition system 1 is abnormal, and the process flow is suspended.

[0061] When the position of the wafer 20 is abnormal, a gap will be generated between the wafer 20 and the heater 12, and the plasma will diffuse into the gap and partially contact the heater 12. In this case, part of the DC signal can enter the shower plate 13 with the help of plasma after passing through the heating plate, and the resistance of the wafer 20 is partially short-circuited, and the total resistance formed by the wafer 20 and the heater 12 is reduced. In this case, the electrical parameters detected by the detection module 15 will have a difference compared with the normal electrical parameters. In this case, the measured electrical parameters will not match the preset parameters, so it is judged that the placement of the wafer 20 is abnormal. In order to avoid abnormal back plating and waste of working hours, the process flow can be suspended and the wafer 20 can be re-placed. In some cases, the electrical parameters may fluctuate, resulting in misjudgment. In order to improve this situation, the duration of the abnormal electrical parameters can be detected. For details, please refer to the following embodiments.

[0062] If the electrical parameters do not match the preset parameters, the wafer 20 position detection method may further include:

[0063] S70: Continuously obtain the electrical parameters between the heater 12 and the shower plate 13 through the detection module 15 .

[0064] In the case where the electrical parameters do not match the preset parameters, the electrical parameters may not match the preset parameters due to vibration of the wafer 20, insufficient plasma ionization, etc. In order to reduce misjudgment due to the above reasons, the following method can be used for detection.

[0065] S80: Obtaining the duration during which the electrical parameters between the heater 12 and the shower plate 13 do not match the preset parameters.

[0066] Problems such as insufficient plasma ionization or vibration of the wafer 20 can be improved by placing the wafer 20 for a certain period of time, waiting for the plasma to be fully ionized or waiting for the wafer 20 to return to stability. Therefore, in the case where the electrical parameters do not match the preset parameters, the misjudgment caused by the above situation can be reduced by detecting the duration of the mismatch. For example, the determination of the duration of the mismatch can be to continuously detect the electrical parameters, and then intercept the duration of the mismatch from the detection results. Alternatively, the determination of the duration of the mismatch can be to continuously monitor the electrical parameters and stop the detection after the electrical parameters return to normal.

[0067] S90: Determine whether the duration is greater than or equal to a preset duration.

[0068] In some embodiments, the maximum duration of continuous monitoring of the electrical parameters may be equal to a preset duration. That is, if the duration of continuous monitoring is longer than the preset duration, even if the electrical parameters return to normal at a later time, the duration of the abnormality will be greater than or equal to the preset duration. Therefore, the maximum duration of continuous monitoring may be equal to the preset duration.

[0069] S100: If the duration is greater than the preset duration, it is confirmed that there is an abnormality in the placement of the wafer 20;

[0070] If the duration is greater than the preset time, it means that the wafer 20 has not recovered to a normal state within the preset time, confirming that there is an abnormality in the placement of the wafer 20.

[0071] S110: If the duration is less than the preset time, the wafer 20 is re-marked as normal.

[0072] If the duration is less than the preset time, it means that within the preset time, the ionization of the plasma or the vibration of the wafer has returned to normal over time, and the placement of the wafer 20 has also returned to normal. In this case, the state of the wafer 20 can be marked from the abnormal state to the normal state, and the process can continue.

[0073] In summary, the heater 12 can carry and heat the wafer 20, and the spray plate 13 can introduce process gas to the heater 12. The DC voltage module 14 can apply a positive voltage or a negative voltage to one of the heater 12 or the spray plate 13. The DC voltage module 14 can form a detection circuit with the detection module 15 to detect the electrical parameters between the spray plate 13 and the heater 12. Due to the difference in the distribution of ionized process gas in the process chamber 111 when the wafer 20 is placed normally or abnormally. Based on this, the electrical parameters between the spray plate 13 and the heater 12 will be different due to the placement of the wafer 20. In this way, detecting the electrical parameters by the detection module 15 can monitor whether the wafer 20 is placed normally.

[0074] The above are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A deposition system, characterized in that: include: A main body, wherein a process cavity is formed inside the main body; A heater is disposed in the process chamber, and the heater is used to carry a wafer; A shower plate is mounted on the main body, one side of the shower plate is arranged opposite to the heater, and the space between the heater and the shower plate is used to accommodate process gas; A DC voltage module, connected to one of the spray plate and the heater, for applying a DC voltage; A detection module, connected to the other of the shower plate and the heater, for detecting electrical parameters between the shower plate and the heater; The radio frequency source module is connected to the shower plate and is used to apply a radio frequency field in the process chamber.

2. The deposition system according to claim 1, characterized in that: The detection module is a voltage detection module, one end of which is electrically connected to the spray plate, and the other end is electrically connected to the DC voltage module; one end of the DC voltage module is electrically connected to the heater, and the other end is electrically connected to the voltage detection module.

3. The deposition system according to claim 2, characterized in that: The voltage detection module includes a detection resistor and a detection probe, and the detection resistor and the detection probe are connected in parallel to form the voltage detection module.

4. The deposition system according to claim 1, characterized in that: One end of the DC voltage module is electrically connected to the heater, and the other end is grounded.

5. The deposition system according to claim 1, characterized in that: The detection module is a voltage detection module, which includes a detection resistor and a detection probe. The detection probe is connected in parallel with the detection resistor. One end of the detection resistor is electrically connected to the shower plate, and the other end is grounded.

6. The deposition system according to claim 5, characterized in that: One end of the detection probe is electrically connected between the detection resistor and the shower plate, and the other end is grounded.

7. The deposition system according to claim 1, characterized in that: The heater and the shower plate are electrically connected via the process chamber and the wafer.

8. The deposition system according to claim 1, characterized in that: The deposition system further includes a bellows, which is sleeved on the outer circumference of the heater, and the heater is movably connected to the main body.

9. The deposition system according to claim 1, characterized in that: The radio frequency source module comprises an AC power supply and a matcher, wherein the AC power supply is connected in series with the matcher, one end of the AC power supply is grounded, and one end of the matcher is electrically connected to the shower plate.

10. A wafer position monitoring method, characterized in that: Using the deposition system according to any one of claims 1 to 9, the steps include: Introducing a detection gas into the process chamber; Ionizing the detection gas; Acquiring electrical parameters between the heater and the shower plate through the detection module; comparing the electrical parameters with preset parameters; If the electrical parameters match the preset parameters, it is determined that the wafer placement in the deposition system is normal and the process flow can continue; If the electrical parameters do not match the preset parameters, it is determined that there is an abnormality in the wafer placement in the deposition system, and the wafer is marked as abnormal.

11. The method according to claim 10, characterized in that: After the step of if the electrical parameters do not match the preset parameters, the method further includes: Continuously acquiring electrical parameters between the heater and the spray plate through a detection module; Obtaining the duration of the mismatch between the electrical parameters between the heater and the spray plate and the preset parameters; Determine whether the duration is greater than or equal to the preset duration; If the duration is longer than the preset time, it is confirmed that there is an abnormality in the wafer placement; If the duration is less than the preset time, the wafer is re-marked as normal.

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