A gas detection system for compound semiconductor thin film deposition

Abstract

This invention relates to the field of compound semiconductor manufacturing technology, and more particularly to a gas detection system for compound semiconductor thin film deposition, comprising a sensing and detection unit, an information management and control unit, an emergency interconnection unit, and an identification and recovery unit. This invention ensures the safe and reliable operation of semiconductor surface processing, avoids wafer contamination or scrap, improves stability and safety, and is applicable to fields such as physical vapor deposition and chemical vapor deposition.

Description

Technical Field

[0001] This invention relates to the field of compound semiconductor manufacturing technology, and in particular to a gas detection system for compound semiconductor thin film deposition. Background Technology

[0002] Compound semiconductor thin film deposition is a core process in substrate surface processing. Key parameters such as film uniformity, film thickness, and reactant composition directly affect product performance and yield. During compound semiconductor thin film deposition, process gases such as ammonia, silane, ethyl silicate, dichlorosilane, and Freon are widely used. These gases are typically flammable, explosive, toxic, and hazardous. Due to the extremely high cleanliness requirements of the production environment, 24 / 7 on-site monitoring is impossible. Gas leaks could lead to serious consequences such as explosions, personnel poisoning, or equipment damage.

[0003] Furthermore, if unfinished wafers or other substrate materials are removed during a process interruption, they are highly susceptible to contamination or excessive film thickness due to repeated processing, resulting in significant losses. Summary of the Invention

[0004] The purpose of this invention is to provide a gas detection system for compound semiconductor thin film deposition to solve the technical problems existing in the monitoring of process gas leaks, risk response, and process recovery after preparation interruption in the current compound semiconductor thin film deposition process.

[0005] This invention provides a gas detection system for compound semiconductor thin film deposition, comprising:

[0006] The system includes a data interconnection sensing and detection unit, an information management and control unit, an emergency interconnection unit, and an identification and recovery unit. The sensing and detection unit, used to monitor and collect signals in process gas leakage scenarios, includes at least a sensor, a shielded signal transmission line, a programmable controller, and a host computer. The information management and control unit, used for rapid response and control, includes at least a flow meter, a solenoid valve, a pneumatic valve, a connecting line, a programmable controller, and a host computer. The emergency interconnection unit, used to enable linkage between the gas detection system and other safety systems, includes at least a central control unit and a cloud server.

[0007] The identification and recovery unit is used to identify and recover the process flow after the equipment manufacturing process is interrupted.

[0008] In some embodiments, the sensor includes at least an electrochemical sensor, a catalytic combustion sensor, and an oxygen concentration sensor; wherein the electrochemical sensor is used to detect phosphine, silane and their chlorinated derivatives, the catalytic combustion sensor is used to detect hydrogen, and the oxygen concentration sensor is used to detect oxygen.

[0009] In some embodiments, the detection limit of the electrochemical sensor is 0.1 ppm, the detection range of the catalytic combustion sensor is 0%-100% LEL, and the oxygen concentration sensor is used to ensure that the ambient oxygen content is greater than 19.5%.

[0010] In some embodiments, the programmable controller within the sensing unit has a built-in temperature compensation module for correcting the effect of ambient temperature on the accuracy of the sensor.

[0011] In some embodiments, the information management and control unit performs response and control based on analog-to-digital conversion and data transmission, wherein the analog-to-digital conversion and display time is less than or equal to 1 second.

[0012] In some embodiments, the emergency interconnection unit connects the gas detection system with the exhaust ventilation system and the fire protection system via the central control unit; when the central control unit detects a level 2 or level 3 risk alarm, the host computer uploads real-time process data to the central control unit and records it synchronously to the cloud server.

[0013] In some embodiments, the identification and recovery unit adopts a corresponding recovery strategy based on the process step at which the equipment was interrupted.

[0014] In some embodiments, the recovery strategy includes at least the following: when the preparation interruption is during boat placement, the host computer controls the process to jump directly to boat removal during recovery, completing subsequent process steps; when the preparation interruption is during vacuuming, constant temperature, and constant pressure, the host computer controls the process to jump directly to pressure return during recovery, completing subsequent process steps; when the preparation interruption is during the coating step, the host computer needs to interact with the central control computer to perform calculations during recovery, wherein the total process time for the coating step is T, and the time already performed is T1, then a time T needs to be calculated. N and time T N Importing this into the process, the host computer controls the jump to vacuuming, completing subsequent temperature and pressure control, and then temporarily changing the time for the corresponding coating step to T. N The process continues until the entire process is completed. If the preparation is interrupted during the process of evacuating residual reactive gases, purging, cleaning, or backpressure, the host computer will directly jump to the process step at the time of the interruption and complete the subsequent process steps upon recovery. If the preparation is interrupted during the process of unloading the boat, the host computer will directly jump to the process of unloading the silicon wafer upon recovery and complete the subsequent process.

[0015] It should be noted that, based on the influence of the reaction chamber volume and the flow field retention effect, T, T1, and T NThe calculation method is related to the reacted gaseous precursors. By installing a digital recording gas flow sensor in the exhaust gas recovery pipeline, if the coating step is abnormally interrupted, the flow rate of the reacted gaseous precursors can be deduced from the recorded exhaust gas flow rate. The relationship between the total flow rate of the coating gaseous precursors, the flow rate of the reacted gaseous precursors, and T and T1 is: Total flow rate of coating gaseous precursors : Flow rate of reacted gaseous precursors = T : T1. Therefore, T1 can be obtained from the flow rate of the reacted gaseous precursors, and then T can be calculated. N The calculation formula is as follows: T N =TT 1。

[0016] In some embodiments, the sensor arrangement is designed according to the gas density characteristics. For gases denser than air, the sensors are arranged 30cm to 50cm above the ground; for gases less dense than air, the sensors are arranged 15cm to 20cm above the ceiling above the pipeline.

[0017] In some embodiments, the sensors are arranged at a distance of 10cm to 12cm at valves and joints.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The sensing and detection unit enables full coverage of gas leakage scenarios and accurate signal acquisition, ensuring the safe and reliable operation of semiconductor surface processing.

[0020] By identifying and recovering abnormal interruptions, the recovery unit intelligently records and restores the process, avoiding wafer removal contamination and over-processing that could lead to damage or scrap.

[0021] By leveraging the risk classification and emergency response capabilities of the emergency interconnection unit, the stability and safety of equipment operation are significantly improved.

[0022] Furthermore, this invention is also applicable to processes such as physical vapor deposition (PVD), chemical vapor deposition (CVD), and atomic layer deposition (ALD) involved in compound semiconductor thin film deposition, and can be extended to fields such as epitaxial growth, plasma etching, and dry cleaning, and has broad application prospects. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1This is a schematic diagram illustrating the system architecture and control flow principle of the present invention;

[0025] Figure 2 This is a schematic diagram of the core layer of risk classification and control in this invention;

[0026] Figure 3 This is a schematic diagram of the thin film deposition process of the present invention;

[0027] Figure 4 This is a schematic diagram of the sensor detection and response process of the present invention. Detailed Implementation

[0028] The following will be based on embodiments of the present invention. Figures 1-4 The technical solutions in the embodiments of the present invention will be clearly and completely described together. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0029] Partial interpretation:

[0030] 1. STEL: Short-term exposure limit concentration refers to the highest permissible concentration of a chemical substance that an employee may be exposed to for a short period of time (usually 15 minutes), provided that the number of exposures in a workday does not exceed 4 times and the interval between each exposure is at least 60 minutes, and that this concentration will not cause acute or chronic harm to health (such as irritation, poisoning, organ damage, etc.).

[0031] 2. LEL: Lower Explosive Limit, refers to the lowest concentration (usually expressed as volume percentage % VOL or ppm) at which a flammable gas / vapor mixed with air can explode upon contact with an ignition source; below this concentration, the flammable components in the mixture are insufficient to form an explosive atmosphere.

[0032] 3. ppm: Parts per million (ppm) concentration, representing the percentage of the target substance by volume (or mass) in a unit volume (or mass) of a mixture. (Equivalent to 0.0001%).

[0033] Example

[0034] This embodiment provides a gas detection system for compound semiconductor thin film deposition, including a data interconnected sensing and detection unit, an information management and control unit, an emergency interconnection unit, and an identification and recovery unit. The sensing and detection unit, used to monitor and collect signals in process gas leakage scenarios, includes at least a sensor, a shielded signal transmission line, a programmable controller, and a host computer. The information management and control unit, used for rapid response and control, includes at least a flow meter, a solenoid valve, a pneumatic valve, connecting lines, a programmable controller, and a host computer. The emergency interconnection unit, used to enable linkage between the gas detection system and other safety systems, includes at least a central control unit and a cloud server. The identification and recovery unit is used to identify and restore the process flow after equipment fabrication is interrupted.

[0035] To better understand this invention, the details are as follows:

[0036] The sensing and detection unit monitors the process gas in real time using sensors, including at least an electrochemical sensor, a catalytic combustion sensor, and an oxygen concentration sensor. These sensors are adapted and arranged according to the gas characteristics. For example, if a silane pipeline leaks in the special gas room, the electrochemical sensor will trigger a level two alarm when it detects a concentration of 0.55 ppm. At this time, the sensor transmits the detection signal to the programmable controller (PLC) through a shielded signal transmission line. The PLC then uploads the signal to the host computer. The host computer analyzes and processes the received data and feeds the results back to the central control computer. The central control computer sends a closing command to the solenoid valve through a digital signal transmission link, cutting off the main outlet valve of the silane source cabinet in the special gas room. At the same time, it starts the exhaust system, increasing its motor power to 120% to discharge the leaked gas. If the concentration in the leak area does not drop below 0.2 ppm within 30 seconds and rises to 1.1 ppm, a level three alarm is triggered. The central control computer notifies personnel to evacuate through the broadcast device and starts the sprinkler system to dilute the toxic gas.

[0037] For information on Level 1, Level 2, and Level 3 risks, please refer to Table 1 below:

[0038]

[0039] Understandably, taking silane as an example, according to GBZ2.1-2019, the STEL of this gas is 1.0 ppm, so an alarm will be triggered if the detected silane leakage concentration exceeds 0.05 ppm.

[0040] The aforementioned sensor array layout is designed based on gas density characteristics. For gases denser than air, such as ammonia, the sensors are placed 30cm-50cm above the ground; for gases less dense than air, such as hydrogen, the sensors are placed 15cm-20cm above the ceiling on the pipeline; in high-leakage locations such as valves and joints, the sensor placement distance is controlled within 10cm-12cm; in addition, in some optional embodiments, if the distance between secondary distribution or equipment end pipelines is long, a sensor of the same model is placed every 5m-8m.

[0041] Key components employ a dual-sensor redundancy strategy. For example, two electrochemical sensors are installed at the gas monitoring point in the chamber to prevent monitoring interruptions due to single-point failures. Furthermore, the sensing unit includes a compensation and calibration function. The programmable controller has a built-in temperature compensation module to correct for the influence of ambient temperature on sensor accuracy. Zero-point calibration is performed weekly, and range calibration is performed monthly to ensure long-term sensor stability. It should be noted that the operating principle of the temperature compensation module is the same as that of thermocouple calibration, and will not be elaborated upon here.

[0042] The information management and control unit responds and controls through flow meters, solenoid valves, pneumatic valves, connecting lines, programmable controllers, and computers. The analog-to-digital conversion aperture time is controlled within 1 second to ensure the real-time performance of signal acquisition and processing. The central control computer transmits data with the production programmable controller, and the equipment host computer transmits data with the process programmable controller. The two computers transmit data to each other and achieve mutual control.

[0043] The central control unit operates at a higher level than the equipment's host computer, supporting IoT connectivity between multiple devices. For example, in the coating process, a flow meter monitors gas flow and uploads the data to a programmable controller. After analysis, the controller adjusts the opening of solenoid valves and pneumatic valves to ensure precise control of process parameters. The connecting cables employ a shielded design to reduce signal interference and improve data transmission reliability. It should be noted that, based on the foregoing, in some optional implementations, the information management and control unit can be macroscopically divided into secondary sub-units and equipment control sub-units.

[0044] The emergency interconnection unit connects the gas detection system with the exhaust ventilation system and the fire safety system via a central control unit. When the central control unit detects a level 2 or 3 risk alarm, the equipment's host computer uploads real-time process data to the central control unit and simultaneously records it to the workshop cloud server for subsequent process recovery. In the case of a level 2 alarm, the alarm light illuminates red, and a high-frequency beeping alarm alerts operators. If the leak continues to worsen and triggers a level 3 alarm, the central control unit sends a shutdown command to the equipment via a digital signal transmission link, simultaneously activating the fire safety system and notifying personnel to evacuate via a broadcast system.

[0045] Identification and recovery unit combination Figure 3 The process flow is explained, which consists of 11 steps, including loading silicon wafers, placing the boat, vacuuming, constant temperature and pressure, coating, evacuating residual reaction gases, purging and cleaning, backpressure, boat removal, and unloading silicon wafers.

[0046] Different recovery strategies are adopted when the interruption occurs at different steps, specifically:

[0047] When an interruption occurs in step 2, the host computer controls the device to skip directly to step 10 to complete the subsequent process; when an interruption occurs in steps 3, 4, or 5, the host computer controls the device to skip directly to step 9 to complete the subsequent process; when an interruption occurs in step 6, the host computer needs to interact with the central control computer for calculation. If the total time for the coating process is T, and the time already taken is T1, then a time T needs to be calculated. N and time T N Import it into the process. The equipment control jumps to step 3 to complete the subsequent steps 4 and 5, and then temporarily changes the time of step 6 to T. N This continues until the entire process is complete. N The rules for T's value are as follows: N =T-T1; When the interruption occurs in step 7, step 8 or step 9, the host computer of the equipment will directly jump to the process step at the time of the interruption to complete the subsequent process; when the interruption occurs in step 10, the host computer of the equipment will directly jump to step 11 to complete the subsequent process.

[0048] It is understood that, in practical applications, this invention is applicable to processes such as Physical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), and Atomic Layer Deposition (ALD), and can also be extended to fields such as epitaxial growth, plasma etching, and dry cleaning. For example, in CVD processes, when the process gases are silane and ammonia, electrochemical sensors and catalytic combustion sensors monitor the two gases respectively; if a silane leak occurs, the system responds step-by-step according to the above process to ensure the stability and safety of equipment operation. Simultaneously, the identification and recovery unit adopts corresponding recovery strategies based on the process step at the time of interruption, avoiding wafer contamination and damage or scrap due to over-processing.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0050] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A gas detection system for compound semiconductor thin film deposition, characterized in that, include: The system includes a data interconnected sensing and detection unit, an information management and control unit, an emergency interconnection unit, and an identification and recovery unit. The sensing and detection unit, used to monitor and collect signals in process gas leakage scenarios, includes at least a sensor, a shielded signal transmission line, a programmable controller, and a host computer. The information management and control unit, used for rapid response and control, includes at least a flow meter, a solenoid valve, a pneumatic valve, a connecting line, a programmable controller, and a host computer. The emergency interconnection unit, used to enable linkage between the gas detection system and other safety systems, includes at least a central control unit and a cloud server. The identification and recovery unit is used to identify and restore the process flow after equipment manufacturing is interrupted. The identification and recovery unit adopts a corresponding recovery strategy based on the process step at which the equipment was interrupted. The recovery strategy includes at least the following: if the preparation interruption is during boat placement, the host computer will directly jump to boat removal during recovery to complete subsequent process steps; if the preparation interruption is during vacuuming, constant temperature, or constant pressure, the host computer will directly jump to pressure return during recovery to complete subsequent process steps; if the preparation interruption is during the coating step, the host computer needs to interact with the central control computer for calculations during recovery, where the total process time for the coating step is T, and the already completed process time... If the time is T1, a time TN needs to be calculated and imported into the process. The host computer controls the step to vacuuming to complete the subsequent constant temperature and pressure. Then, the time of the corresponding coating step is temporarily changed to TN until the entire process is completed. If the preparation is interrupted during the evacuation of residual reaction gas, purging, cleaning, or backpressure, the host computer controls the step to jump directly to the process step at the time of the interruption to complete the subsequent process steps. If the preparation is interrupted during the unloading of the boat, the host computer controls the step to jump directly to unloading the silicon wafer to complete the subsequent process.

2. The system according to claim 1, characterized in that, The sensor includes at least an electrochemical sensor, a catalytic combustion sensor, and an oxygen concentration sensor; wherein the electrochemical sensor is used to detect phosphine, silane and their chlorinated derivatives, the catalytic combustion sensor is used to detect hydrogen, and the oxygen concentration sensor is used to detect oxygen.

3. The system according to claim 2, characterized in that, The detection limit of the electrochemical sensor is 0.1 ppm, the detection range of the catalytic combustion sensor is 0%-100% LEL, and the oxygen concentration sensor is used to ensure that the ambient oxygen content is greater than 19.5%.

4. The system according to claim 1, characterized in that, The programmable controller within the sensing and detection unit has a built-in temperature compensation module for correcting the effect of ambient temperature on the accuracy of the sensor.

5. The system according to claim 1, characterized in that, The information management and control unit performs response and control based on analog-to-digital conversion and data transmission, wherein the analog-to-digital conversion and display time is less than or equal to 1 second.

6. The system according to claim 1, characterized in that, The emergency interconnection unit connects the gas detection system with the exhaust ventilation system and the fire protection system via the central control unit. When the central control unit detects a level 2 or level 3 risk alarm, the host computer uploads real-time process data to the central control unit and records it synchronously to the cloud server.

7. The system according to claim 1, characterized in that, The sensor arrangement is designed according to the gas density characteristics. For gases denser than air, the sensors are arranged 30cm to 50cm above the ground; for gases less dense than air, the sensors are arranged 15cm to 20cm above the ceiling above the pipeline.

8. The system according to claim 1, characterized in that, At valves and joints, the sensors are arranged at a distance of 10cm to 12cm.

Images