Optical sensor, spectroscopic detection system and semiconductor process equipment

Abstract

The application relates to an optical sensor, a spectrum detection system and a semiconductor process equipment, the sensor comprising: a self-plasma cavity, comprising a cavity, a coil arranged outside the cavity, and an air inlet pipe and an air outlet pipe arranged on opposite two side walls of the cavity and connected to the cavity, the air inlet pipe and the air outlet pipe being used for the flow of a measured gas, a detection port being further arranged on the side wall of the cavity, the detection port, the air inlet pipe and the air outlet pipe being located on different side walls, and the coil being connected to a radio frequency power source to form a plasma and generate glow discharge for the measured gas in the cavity; a detection pipe, one end of the detection pipe being connected to the cavity and communicated with the detection port, the other end of the detection pipe being closed and provided with a light-transmitting detection window, and a stepped channel being arranged in the detection pipe and communicated between the two ends, and the inner diameter of the stepped channel decreasing from one end to the other end. The application can be communicated with an exhaust pipe of a semiconductor equipment, timely respond to the reaction change in the semiconductor process equipment, reduce test delay, and improve the real-time performance and accuracy of the measurement result.

Description

Technical Field

[0001] This application relates to the field of semiconductor detection technology, specifically to an optical sensor, a spectral detection system, and semiconductor process equipment. Background Technology

[0002] Self-plasma optical emission spectroscopy (SPOES) sensors are a new generation of sensor technology that integrates plasma generation technology and spectral analysis technology. SPOES sensors have a self-plasma chamber independent of semiconductor process equipment, allowing plasma discharge to occur independently of the equipment. Therefore, process diagnostics can be performed without affecting the semiconductor process equipment, and it can be applied to remote plasma systems (RPS), where plasma discharge does not occur in the main chamber of the equipment. Thus, compared to sensors using traditional mass spectrometry or EPD sensors, it is a sensor applicable to real-time monitoring of a wider range of processes.

[0003] The working principle of the SPOES sensor is as follows: A plasma chamber is set on the side of the exhaust pipe of the semiconductor process equipment. There is an electromagnetic coil outside the plasma chamber. The gas in the exhaust pipe enters the plasma chamber through the diffusion effect. When radio frequency power is applied to the electromagnetic coil, the gas in the chamber is ionized to form plasma and generate glow discharge. The glow discharge is collected by an optical module through an optical window on the plasma chamber for subsequent data processing and analysis.

[0004] Gas enters the plasma chamber only through diffusion, resulting in slow gas exchange and significant lag, making it unable to respond promptly to changes in the semiconductor process equipment's internal reaction. Furthermore, the gas in the exhaust pipe contains metal ions, which can easily contaminate the optical window, preventing the optical module from acquiring glow discharge and affecting the final data processing and analysis.

[0005] Therefore, there is a need for a self-plasma optical sensor that can respond promptly to changes in the reaction within the semiconductor process cavity. Summary of the Invention

[0006] The technical problem to be solved by this application is to provide an optical sensor, a spectral detection system, and a semiconductor process equipment, which can be connected to the exhaust pipe of the semiconductor process equipment, respond in a timely manner to changes in the reaction within the semiconductor process equipment, reduce test delay, and improve the real-time performance and accuracy of measurement results.

[0007] According to a first aspect of the embodiments of this application, an optical sensor is provided, comprising: a plasma cavity, including a chamber and a coil disposed outside the chamber, wherein an inlet pipe and an outlet pipe for the flow of a gas to be measured are connected to two opposite side walls of the chamber, and a detection port is also provided on the side wall of the chamber, wherein the detection port and the inlet pipe and the outlet pipe are located on different side walls, and the coil is used to be connected to a radio frequency power supply to form plasma for the gas to be measured in the chamber and generate glow discharge;

[0008] The detection tube has one end connected to the chamber and communicating with the detection port, allowing the glow light in the chamber to enter the detection tube. The other end of the detection tube is closed and has a light-transmitting detection window. The detection tube has a stepped channel connecting the two ends, and the inner diameter of the stepped channel decreases from one end to the other.

[0009] In one embodiment, an electric field structure is also included at the detection tube, the electric field structure comprising two electric field plates symmetrically distributed about the axis of the stepped channel, one of the two electric field plates being connected to a power source and the other being grounded.

[0010] In one embodiment, at least two drainage plates are provided at the detection port, and all the drainage plates are formed with two ends of different diameters, wherein the smaller diameter end is located in the chamber, and the larger diameter end is located in the stepped channel.

[0011] In one embodiment, the stepped channel is provided with at least one section of the narrowing structure. Each section of the narrowing structure includes a plurality of dust collection plates circumferentially distributed around the axis of the stepped channel, and the ends of all the dust collection plates near the detection window form a narrowed portion. The inner diameter of the narrowed portion is smaller than the inner diameter of the stepped channel at the corresponding narrowed portion.

[0012] In one embodiment, the air intake pipe is provided with a dust collection box, and / or, the port where the chamber is connected to the air intake pipe is provided with a collection plate for collecting metal ions.

[0013] In one embodiment, the chamber is provided with a reflector array that guides the glow discharge to the detection port, the reflector array being an array of multiple reflectors.

[0014] In one embodiment, the chamber is provided with a reflector that guides the glow discharge to the detection port, and a heating structure for heating the reflector.

[0015] In one embodiment, the reflector has a reflective surface recessed away from the detection port, and the reflective surface is parabolic.

[0016] In one embodiment, the inner wall surface of the chamber has a reflective coating.

[0017] According to a second aspect of the embodiments of this application, a spectral detection system is provided, including a spectrometer and an optical sensor as described in any of the preceding claims, wherein the spectrometer is spaced apart from the detection window to receive glow light in the chamber and perform monitoring and analysis.

[0018] According to a third aspect of the present application, a semiconductor process apparatus is provided, comprising: a process chamber, an exhaust pipe connected to the process chamber, and a spectral detection system as described above, wherein the inlet pipe and the outlet pipe are respectively connected to different sections of the exhaust pipe, and the connection point between the inlet pipe and the exhaust pipe is close to the inlet side of the exhaust pipe connected to the process chamber.

[0019] In one embodiment, the end of the intake pipe connected to the exhaust pipe is provided with an electric field structure for collecting metal ions.

[0020] Compared with the prior art, the beneficial effects of this application are as follows:

[0021] By connecting an inlet pipe and an outlet pipe on opposite side walls of the chamber, the gas to be tested (such as the gas in the exhaust pipe of a semiconductor process equipment) can enter the chamber through the inlet pipe and then flow out through the outlet pipe. This can serve as a branch pipe of the exhaust pipe in the semiconductor process equipment, achieving the same flow rate as the gas in the exhaust pipe. This allows the gas in the exhaust pipe to flow through the chamber in real time, generating glow discharge in the plasma environment. This facilitates timely response to changes in the semiconductor process equipment cavity, enabling real-time detection by a spectrometer, reducing test delay, and improving the accuracy of testing changes in the semiconductor process equipment. In addition, by increasing the distance between the detection window and the chamber through the detection tube, the glow discharge in the chamber can be transmitted to the detection window through the stepped channel in the detection tube, where it is received and analyzed by the spectrometer. Furthermore, the stepped channel in the detection tube slows down the flow rate of the gas to be tested entering the detection tube and allows for the deposition of metal ions in the gas entering the detection tube, preventing contamination of the detection window and improving detection accuracy. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating an autoplasmic optical emission spectroscopy sensor according to an exemplary embodiment;

[0023] Figure 2 This is a schematic diagram of an autoplasmic optical emission spectroscopy sensor according to another exemplary embodiment;

[0024] Figure 3 This is a schematic diagram of a semiconductor process apparatus according to an exemplary embodiment.

[0025] In the picture,

[0026] 1. Self-plasma chamber; 11. Chamber; 12. Coil; 13. Inlet pipe; 14. Outlet pipe;

[0027] 15. Dust collection box; 2. Detection tube; 21. Stepped channel; 22. Detection window; 3. Drainage plate;

[0028] 4. Dust collection plate; 5. Electric field structure; 6. Reflector; 7. Spectrometer; 8. Exhaust pipe. Detailed Implementation

[0029] Unless otherwise defined, the technical or scientific terms used in this specification and claims shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. Specific embodiments of this application will be described below in conjunction with the accompanying drawings. It should be noted that, in order to provide a concise description, this specification cannot exhaustively describe all features of the actual embodiments. Without departing from the spirit and scope of this application, those skilled in the art can modify and substitute the embodiments of this application, and the resulting embodiments are also within the protection scope of this application.

[0030] In a plasma optical emission spectroscopy sensor (SPOES sensor), the gas being measured enters the plasma chamber through diffusion. The gas exchange rate is slow, exhibiting significant hysteresis, and cannot respond promptly to changes in the reaction within the semiconductor process equipment's chamber. Furthermore, the gas discharged from the semiconductor process equipment contains metal ions, which can easily contaminate the optical window and affect the detection results.

[0031] To address the aforementioned technical problems, this application provides a self-plasma optical emission spectroscopy sensor (i.e., an optical sensor). Reference Figure 1 In one specific embodiment, it includes: a plasma cavity 1, comprising a chamber 11 and a coil 12 placed outside the chamber 11. An inlet pipe 13 and an outlet pipe 14 for the flow of the gas to be measured are connected to two opposite side walls of the chamber 11. A detection port is also provided on the side wall of the chamber 11, and the detection port, inlet pipe 13, and outlet pipe 14 are located on different side walls. The coil 12 is used to be electrically connected to a radio frequency power supply (not shown) to form plasma in the gas to be measured in the chamber 11. The body generates glow discharge (i.e., the emitted light can be collected and received by a spectrometer or optical module); detection tube 2, one end of which is connected to chamber 11 and communicates with the detection port, so that the light in chamber 11 can enter the detection tube 2. The other end of the detection tube 2 is closed and has a light-transmitting detection window 22. The detection tube 2 has a stepped channel 21 connecting the two ends, and the inner diameter of the stepped channel 21 decreases from one end to the other end, that is, the inner diameter of the stepped channel 21 decreases in steps from the detection port side to the detection window 22 side.

[0032] In this embodiment, an inlet pipe 13 and an outlet pipe 14 are connected to opposite side walls of the chamber 11. The gas to be tested can enter the chamber 11 through the inlet pipe 13 and then flow out through the outlet pipe 14. This can serve as a branch pipe of the exhaust pipe in the semiconductor process equipment. That is, the inlet pipe 13 and the outlet pipe 14 are connected to the exhaust pipe, which can achieve the same gas flow rate as the exhaust pipe. This allows the gas in the exhaust pipe to flow through the chamber 11 in real time, generating glow discharge in the plasma environment inside the chamber. This facilitates timely response to the reaction changes inside the semiconductor process equipment cavity, and allows for real-time detection by a spectrometer, reducing test delay and improving the understanding of semiconductors. The accuracy of testing changes in process equipment reactions is improved. Furthermore, by increasing the distance between the detection window 22 and the chamber 11 through the detection tube 2, and by using a stepped channel 21 within the detection tube 2, the flow rate of the gas being tested entering the detection tube 2 can be slowed down, further reducing the diffusion rate of the gas within the detection tube. This allows for the deposition of metal ions in the gas entering the detection tube 2. Even if a small amount of gas enters the detection tube 2, due to its limited diffusion rate, the metal ions in the gas mainly deposit on the tube wall near the detection port, avoiding contamination of the detection window 22, extending the sensor's lifespan, eliminating the need for frequent cleaning or replacement of the detection window, and improving detection accuracy. The detection window 22 is a light-transmitting optical lens, facilitating light transmission for collection by the spectrometer; the coil 12 is an energized coil.

[0033] In one embodiment, such as Figure 2 As shown, it also includes an electric field structure 5 placed at the detection tube 2. The electric field structure 5 includes two electric field plates symmetrically distributed about the axis of the stepped channel 21. One of the two electric field plates is connected to a power source, and the other is grounded. In this embodiment, the electric field structure 5 can form a deflection electric field in the detection tube 2, causing positively charged metal ions in the gas in the stepped channel to be deflected and deposited on the tube wall of the stepped channel, further reducing the number of metal ions reaching the detection window side.

[0034] In another embodiment, such as Figure 2 As shown, at least two drainage plates 3 are provided at the detection port. All drainage plates 3 have two ends with different diameters. The smaller diameter end is located in the chamber 11, and the larger diameter end is located in the stepped channel 21. In this embodiment, by setting drainage plates 3 at the detection port to form a funnel-shaped drainage port, the gas in the chamber 11 is depressurized from the smaller diameter end to the larger diameter end, changing the flow rate. This further makes it easier for metal ions in the gas to deposit on the drainage plates 3, preventing them from moving towards the detection window side.

[0035] Specifically, the stepped channel 21 is provided with at least one section of narrowing structure. Each section of narrowing structure includes multiple dust collection plates 4 circumferentially distributed around the axis of the stepped channel, and the ends of all dust collection plates 4 near the detection window form a constricted portion. The inner diameter of the constricted portion is smaller than the inner diameter of the corresponding constricted portion of the stepped channel 21. In this embodiment, by setting multiple sections of narrowing structure and further forming a constricted portion with an even smaller inner diameter through the dust collection plates 4, a funnel-shaped channel is formed at each step. The larger end of the funnel-shaped channel faces the detection port, and the smaller end faces the detection window. This allows a small amount of metal ions in the gas flowing towards the detection window to be deposited on the dust collection plates, further preventing metal ions from flowing to the detection window. This makes the section of the stepped channel 21 near the detection window a clean channel with only a small amount of metal ions or no metal ions, and has no impact on the detection window.

[0036] Specifically, the aforementioned electric field structure 5, the flow guide plate 3 in the detection tube 2, and the dust collection plate 4 are all provided. In this embodiment, by setting the distance between the detection window and the detection port of the chamber, the funnel-shaped flow guide formed by the flow guide plate 3 allows the plasma glow in the chamber to pass through normally and be received and detected by the spectrometer through the detection window. The gas to be tested mainly contains a mixture of metal ion pollutants, inert gases, etc. After being blocked by the flow guide plate 3, the pressure is reduced and the flow rate is slowed when entering the detection tube 2. At the same time, the upper and lower electric field plates of the electric field structure 5 will give the metal ions a downward deflection force, so that the metal ions slow down the flow rate in the first section of the stepped channel 21. The dust collection plates 4 in the subsequent two sections further reduce the diameter of the stepped channel 21, so that the gas that has been depressurized is further reduced from flowing in. With the deflection force of the electric field, the positively charged metal ions are deposited at the dust collection plate 4 and will not enter the final section, thus avoiding contamination of the detection window.

[0037] In one implementation, see Figure 2 As shown, a dust collection box 15 is provided in the air inlet pipe 13, and / or a collection plate for collecting metal ions is provided at the port connecting the chamber 11 to the air inlet pipe 13. Specifically, the dust collection box 15 can be a honeycomb structure, grounded as a whole, and negatively charged, attracting positively charged metal ions. After the self-plasma optical emission spectroscopy sensor is powered off / finished, the dust collection box 15 can be replaced to prevent excessive metal ion deposition. The collection plate can collect metal ions, further preventing the gas entering the chamber from carrying too many metal ions. Other structures for collecting metal ions can also be set on the air inlet pipe, such as a funnel depressurization structure, which reduces the flow rate of the gas before it enters the chamber, thereby depositing metal ions in the gas on the funnel wall. The structure for collecting metal ions on the air inlet pipe is not limited to this and can be set according to process requirements to reduce the metal ions carried by the gas entering the chamber.

[0038] In one implementation, see Figure 2As shown, the chamber 11 is equipped with a reflector array that guides the glow discharge to the detection port. The reflector array is an array of multiple reflectors 6. In this embodiment, to enhance the light entering the detection tube 2, a reflector array is provided in the chamber 11. Each reflector 6 guides the glow discharge in the chamber to the detection port, improving the light collection efficiency and allowing more light to pass through the reflector array. Figure 2 The data is transmitted to the detection window 22 in the direction of the dashed arrow, improving detection accuracy.

[0039] In another embodiment, the chamber 11 is equipped with a reflector 6 that guides the glow discharge to the detection port, and a heating structure for heating the reflector. This embodiment uses a reflector 6 positioned in front of the detection port to collimate and converge light from all directions within the chamber 11, allowing more light to enter the detection window 22 through the stepped channel 21, effectively improving light collection efficiency. Furthermore, to prevent metal ion contamination of the reflector 6, it is heated to 150°C. At this temperature, metal ions are difficult to deposit on the reflector 6. The reflector 6 can use a metal substrate with low CTE, making it less prone to deformation at high temperatures (e.g., above 100°C). An ultraviolet reflective film is deposited on the metal substrate, and a silicon dioxide protective film is used on the outer layer to prevent oxidation of the coating at high temperatures.

[0040] Specifically, the aforementioned reflector 6 has a reflective surface that is concave away from the detection port, and the reflective surface is parabolic. For example, if the radial diameter of the reflector is 3-4.5cm, the lateral length is 3.3-3.8cm, and the light emission angle is 1.3°-1.5°, this reflective parabolic surface can be integrated into a reflector cup, which can converge the light emitted from various angles in the cavity into a collimated beam, enter the stepped channel 21, and facilitate output through the detection window 22, thereby improving the light collection efficiency.

[0041] In one embodiment, the inner wall of chamber 11 has a reflective coating. For example, by coating the inner wall of chamber 11 with an ultraviolet aluminum film, light that cannot directly enter the detection tube 2 will be repeatedly reflected on the inner wall until it is weakened or enters the stepped channel 21 through the reflector 6.

[0042] Specifically, when the above-mentioned electric field structure 5, the flow guide plate 3 and the dust collection plate 4 in the detection tube 2 are all provided, a reflector 6 is provided in the chamber 11. The inner wall surface of the chamber 11 has a reflective coating. While preventing metal ions in the gas from entering the stepped channel and reaching the detection window, it increases the amount of light (i.e., glow discharge) in the chamber 11 entering the detection tube 2, which is convenient for being collected and received by an external spectrometer, facilitates data processing and analysis, improves detection accuracy, and responds promptly to the reaction changes in the semiconductor process equipment where the connected exhaust pipe is located, reducing test delay and improving the timeliness and accuracy of reaction detection in the equipment.

[0043] According to a second aspect of the embodiments of this application, see Figure 2As shown, an autoplasmic optical emission spectroscopy detection system is provided, including a spectrometer 7 and an autoplasmic optical emission spectroscopy sensor as described in any of the above claims. The spectrometer 7 is spaced apart from the detection window 22 to receive glow light in the chamber 11 and perform monitoring and analysis.

[0044] According to a third aspect of the embodiments of this application, see Figures 1 to 3 As shown, a semiconductor process apparatus is provided, including: a process chamber, an exhaust pipe 8 connected to the process chamber, and an autoplasmic emission spectrometry (AES) detection system as described above. An inlet pipe 13 and an outlet pipe 14 are respectively connected to different sections of the exhaust pipe 8, and the connection point between the inlet pipe 13 and the exhaust pipe 8 is close to the inlet side of the exhaust pipe 8 connected to the process chamber. During the semiconductor process in the process chamber, the generated exhaust gas is discharged through the exhaust pipe 8. In this embodiment, the AES detection system serves as a branch of the exhaust pipe. The gas in the exhaust pipe 8 (along...) Figure 3 (In the direction of the middle arrow) The gas flows through the inlet pipe 13 into the chamber to generate plasma glow discharge, and then enters the exhaust pipe 8 through the outlet pipe 14. The gas flow rate in the chamber 11 is the same as the flow rate in the exhaust pipe 8, which can realize timely detection and real-time reflection of the reaction changes in the process chamber, improving real-time performance and accuracy. In addition, by increasing the distance between the detection window 22 and the chamber 11 through the detection tube 2, and the step channel 21 inside the detection tube 2, the flow rate of gas entering the detection tube 2 can be slowed down. Combined with the step channel 21, the diffusion rate of gas in the detection tube is further reduced, avoiding contamination of the detection window 22, and further improving the detection accuracy.

[0045] Specifically, the end of the intake pipe 13 connected to the exhaust pipe 8 is provided with an electric field structure for collecting metal ions, thereby reducing the number of metal ions entering the chamber 11 and preventing them from entering the detection tube 2 and contaminating the detection window 22.

[0046] The above description of the embodiments is intended to enable those skilled in the art to understand and apply this application. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without creative effort. Therefore, this application is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope and spirit of this application are within the scope of this application.

Claims

1. An optical sensor, comprising: The plasma chamber includes a chamber and a coil placed outside the chamber. An inlet pipe and an outlet pipe for the gas to be measured are connected to two opposite side walls of the chamber. A detection port is also provided on the side wall of the chamber, and the detection port and the inlet pipe and outlet pipe are located on different side walls. The coil is used to connect to a radio frequency power supply to form plasma and generate glow discharge for the gas to be measured in the chamber. A reflector is provided in the chamber to guide the glow discharge to the detection port. The inner wall surface of the chamber has a reflective coating. The detection tube has one end connected to the chamber and communicating with the detection port, and the other end of the detection tube is closed and has a light-transmitting detection window. The detection tube has a certain length and has a stepped channel connecting the two ends inside the detection tube. The inner diameter of the stepped channel decreases from one end to the other end to slow down the flow rate of the gas to be tested from the detection port into the detection tube, so that the metal ions in the gas to be tested are deposited on the tube wall near the detection port before reaching the detection window.

2. The optical sensor as described in claim 1, characterized in that, It also includes an electric field structure placed at the detection tube, the electric field structure comprising two electric field plates symmetrically distributed about the axis of the stepped channel, one of the two electric field plates being connected to a power source and the other being grounded.

3. The optical sensor as described in claim 1 or 2, characterized in that, At least two drainage plates are provided at the detection port. All drainage plates have two ends with different diameters. The smaller diameter end is located in the chamber, and the larger diameter end is located in the stepped channel.

4. The optical sensor as described in claim 3, characterized in that, The stepped channel is provided with at least one section of the narrowing structure. Each section of the narrowing structure includes multiple dust collection plates distributed circumferentially around the axis of the stepped channel. The ends of all the dust collection plates near the detection window form a narrowed portion. The inner diameter of the narrowed portion is smaller than the inner diameter of the corresponding narrowed portion of the stepped channel.

5. The optical sensor as described in claim 1, characterized in that, The air intake pipe is provided with a dust collection box, and / or, the port where the chamber is connected to the air intake pipe is provided with a collection plate for collecting metal ions.

6. The optical sensor as described in claim 1, characterized in that, The reflectors are multiple and arranged in an array to form a reflector group.

7. The optical sensor as claimed in claim 1, characterized in that, The cavity is equipped with a heating structure for heating the reflector.

8. The optical sensor as described in claim 6 or 7, characterized in that, The reflector has a reflective surface that is recessed away from the detection port, and the reflective surface is parabolic.

9. A spectral detection system, characterized in that, It includes a spectrometer and an optical sensor as described in any one of claims 1 to 8, wherein the spectrometer is spaced apart from the detection window to receive glow light in the chamber and perform monitoring and analysis.

10. A semiconductor process apparatus, characterized in that, include: The process chamber, the exhaust pipe connected to the process chamber, and the spectral detection system as described in claim 9, wherein the inlet pipe and the outlet pipe are respectively connected to different sections of the exhaust pipe, and the connection between the inlet pipe and the exhaust pipe is close to the inlet side of the exhaust pipe connected to the process chamber, so that the gas flow rate in the chamber is the same as the gas flow rate in the exhaust pipe.

11. The semiconductor process equipment as described in claim 10, characterized in that, The end of the intake pipe connected to the exhaust pipe is provided with an electric field structure for collecting metal ions.

Images