Device for monitoring service life of heating body

Abstract

The utility model discloses a heating body life monitoring device, comprising a PLC controller, a liquid crystal display, an electric field intensity detector, an overtemperature protection circuit, an alarm, a PC and an EAP system, the PLC controller is electrically connected with the liquid crystal display, the electric field intensity detector is electrically connected with the PLC controller, and the PLC controller is also electrically connected with the overtemperature protection circuit and is also in signal connection with the PC through the EAP system; the PLC is further electrically connected with an alarm. The alarm is a distance alarm or a time alarm; the service life of the heating body is monitored in real time, and the service life of the waste heating body is fixed, so that the service life of the heating body is prolonged; spare part cost is reduced; the conventional monitoring time consumption is reduced, the time cost is reduced, and the equipment utilization rate and the productivity are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of diffusion furnace, concretely is a kind of heating body life monitoring device. BACKGROUND

[0002] Diffusion furnace is the main equipment for realizing diffusion process (including normal pressure oxidation, annealing, low pressure vapor deposition, atomic layer deposition and all tubular heating processes) in semiconductor production link, and heating body is the heating core component of diffusion furnace, and heating body is converted into heat energy by the way of applying low voltage and large current to the both ends of resistance wire, resistance wire will age with use time, and will slowly deform due to repeated temperature rise and fall (thermal expansion and cold shrinkage, incomplete stress release of resistance wire), so heating body has its service life, and differs from individual to individual (due to the difference in heating wire diameter uniformity, the difference in insulation terminal, the difference in processing process, the difference in use temperature and frequency, the difference in temperature rise and fall rate, the difference in power between ZONE (heating body is generally divided into three or five heating sections, each section is called a ZONE, and ZONE is independent of each other) and other factors).

[0003] For example, the patent with the authorized announcement number CN222298497U discloses a spliced diffusion furnace baffle and diffusion furnace, which comprises a long-cylindrical furnace baffle outer wall, a furnace baffle body formed by splicing a plurality of heating pipes arranged in the furnace baffle outer wall along the length direction of the furnace baffle outer wall, the furnace baffle body comprises at least one first heating pipe and a second heating pipe located at the head end and / or tail end and adjacent to the furnace door, the first heating pipe comprises a metal heating wire for heating the inner cavity of the heating pipe, and the second heating pipe comprises at least one group of electrode rod windings for heating the inner cavity of the heating pipe, the electrode rod windings are silicon-carbon rods or silicon-molybdenum rods.

[0004] The oxide film formed by the above patent is more resistant to peeling, so the use of silicon-carbon rods or silicon-molybdenum rods at the opening of the furnace baffle greatly prolongs the service life; however, the above patent has the following disadvantages: under the prior art, the monitoring method for the service life of the heating body of the diffusion furnace is only to disassemble the equipment for inspection or to replace it directly within a period.

[0005] And disassembly machine, recovery process and other series of actions need 2-4 days, seriously affect the equipment utilization and capacity; Regular inspection period is not controlled, once the heating wire is deformed and touches the silicon carbide tube (silicon carbide is a semiconductor material, and its conductivity is tens of thousands times that of conductor) can cause the silicon carbide tube to be broken by electric shock (because of poor conductivity, a large amount of heat is released at the position where the heating wire contacts the silicon carbide tube, causing the silicon carbide to be locally melted by heat, and the silicon carbide is broken under the action of thermal stress and gravity), resulting in the rejection of the product, the damage of other silicon carbide / quartz parts such as process boat, and other serious property losses, and more seriously, it can cause fire, and the only way to prevent it is to replace the new one after the specified safe life limit.

[0006] Therefore, it is necessary to improve such a structure to overcome the above-mentioned defects. Practical new type content

[0007] The utility model discloses a kind of heating body life monitoring devices, to solve the problems raised in the above background technology.

[0008] To achieve the above object, the utility model provides the following technical scheme:

[0009] A kind of heating body life monitoring device, including PLC controller, liquid crystal display, electric field intensity detector, over-temperature protection circuit, alarm, PC and EAP system, the PLC controller is electrically connected with liquid crystal display, electric field intensity detector is electrically connected PLC controller, PLC controller is also electrically connected with over-temperature protection circuit still through EAP system signal connection PC;The PLC controller is also electrically connected with alarm;The alarm is distance alarm or time alarm;

[0010] Further, PLC controller input end connects non-contact electric field intensity detector, output end connects liquid crystal display, and the operation result is digitized;

[0011] Further, warning limit and safety limit are provided in PLC controller;

[0012] Further, the warning limit triggers PLC controller output signal to alarm, issues alarm signal, while PLC controller output signal to PC, PC output feedback to EAP system switches equipment state to H-ENG (engineering confirmation state), and engineering personnel give processing method according to equipment operating state;

[0013] Further, the safety limit triggers PLC controller output signal to alarm 5, issues alarm signal, while PLC controller output signal to over-temperature protection circuit 4, equipment is automatically cut off heating power supply, while PLC controller output signal to PC, PC output feedback to EAP system switches equipment state to DOWN-PM;

[0014] Further, the electric field intensity detector is a non-contact electric field intensity detector, the range is 10000 V / M, and the precision is 50 V / M.

[0015] Further, the horizontal furnace is provided with two electric field intensity detectors, one at the Load end and the other at the Source end.

[0016] Further, the vertical furnace is provided with eight electric field intensity detectors, four at the BTM end and evenly distributed around the cylindrical heating body in a plane, and four at the TOP end and evenly distributed around the cylindrical heating body in a plane.

[0017] Further, the alarm is an electric field intensity alarm.

[0018] Compared with the prior art, the utility model has the beneficial effects that:

[0019] 1. Real-time monitoring of the service life of the heating body, fixed cycle life of the discarded heating body, improvement of the service life of the heating body, reduction of the cost of spare parts, reduction of the time cost of conventional monitoring, improvement of the utilization rate of equipment and production capacity, and reduction of the time cost of conventional monitoring.

[0020] 2. Avoiding the damage of the SiC tube caused by sudden heating body aging and other potential equipment and property safety problems such as damage of other silicon carbide / quartz pieces and product scrapping, and improving the safety of the diffusion furnace. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic view of a heating body service life monitoring device.

[0022] Figure 2 is a schematic view of the heating body and furnace tube structure of a horizontal furnace.

[0023] Figure 3 is a schematic view of the heating body and furnace tube structure of a vertical furnace.

[0024] Figure 4 is an actual diffusion furnace heating system circuit diagram. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme of the embodiments of the utility model will be described clearly and completely in combination with the drawings in the embodiments of the utility model below. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. The components of the embodiments of the utility model described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the utility model.

[0026] Please refer to Figures 1-4 A heating body life monitoring device, comprising:

[0027] A PLC controller 100;

[0028] A liquid crystal display 200;

[0029] An electric field strength detector 300;

[0030] An over-temperature protection circuit 400 (taking original equipment temperature unit signal);

[0031] An alarm 500;

[0032] A PC 600, using original equipment PC;

[0033] An EAP system 700, existing heating body system;

[0034] The PLC controller 100 is electrically connected with the liquid crystal display 200, the electric field strength detector 300 is electrically connected with the PLC controller 100, the PLC controller 100 is further electrically connected with the over-temperature protection circuit 400 and is further connected with the PC 600 through the EAP system 700 signal; the PLC controller 100 is further electrically connected with the alarm 500; the alarm 500 is a distance alarm 501 or a time alarm 502;

[0035] Further, the PLC controller 100 writes operation program (the distance between the heating body and the furnace pipe <3cm, regarded as parallel uniform electric field, according to E=U / D, E, electric field strength (detecting electric field);

[0036] U, voltage (heating wire voltage, constant value when working);

[0037] D, the distance between the voltage source (heating wire) and the detecting electric field (furnace pipe)), the input end is connected with the non-contact electric field strength detector, the output end is connected with the liquid crystal display, and the operation result is digitized;

[0038] Further, the PLC controller 100 is provided with a warning limit and a safety limit;

[0039] The warning limit triggers the PLC controller 100 to output a signal to the alarm 500, to issue an alarm signal, and at the same time the PLC controller 100 outputs a signal to the PC, and the PC outputs a feedback to the EAP system to switch the device state to H-ENG (engineering confirmation state), and the engineering personnel give a treatment method according to the running state of the device;

[0040] The safety limit triggers the PLC controller 100 to output a signal to the alarm 500, to issue an alarm signal, and at the same time the PLC controller 100 outputs a signal to the over-temperature protection circuit 4, and the device automatically cuts off the heating power supply (at this time the device is powered off and the safety interlock is started, and high-purity protective nitrogen is automatically introduced to protect the product), and at the same time the PLC controller 100 outputs a signal to the PC, and the PC outputs a feedback to the EAP system 700 to switch the device state to DOWN-PM (maintenance downtime state);

[0041] Further, the electric field strength detector 300 is a non-contact electric field strength detector, the range is 10000V / M, and the accuracy is 50V / M, and is installed at both ends of the heating body;

[0042] Two horizontal furnaces are installed, one at the Load end and one at the Source end,

[0043] Eight vertical furnaces are installed (which can be adjusted according to requirements), four at the BTM end (the lowermost end) (which are evenly distributed in a plane around the cylindrical heating body), and four at the TOP end (the uppermost end) (which are evenly distributed in a plane around the cylindrical heating body);

[0044] Further, the alarm is an electric field strength alarm, which defines the warning limit and the safety limit of D (derived from the PLC controller 100 according to E=U / D, D is the distance between the heating wire and the furnace pipe, and D=U / E is calculated by reverse calculation, D is the distance between the heating wire and the furnace pipe);

[0045] As shown in FIG. Figure 2 Each diffusion device is externally connected to a power supply 10 which is basically fixed (380V / 400V / 440V, any one of which can be selected), is transformed via a device end transformer, and according to different processes realized, the working voltage 20 of each ZONE after transformation is distributed to each ZONE (heating zone), which is slightly different but remains a fixed value, and in combination with the rated working current 30 of each ZONE (which is different according to the working environment and the service life of the device), the rated power of each ZONE is fixed.

[0046] In this embodiment, a brand-new heating element with an operating temperature of 1100℃ was used (vertical diffusion furnace, the same applies to horizontal furnace). The output power of each zone under the stable operating state of 1100℃ was monitored. The results showed that the uppermost and lowermost zones had the highest actual output power. According to the theory (theoretically, the uppermost and lowermost zones require higher heating power to maintain a constant temperature due to heat compensation on one side and heat loss on the other side), this is consistent with the theory.

[0047] The temperature processing unit 40 includes a Spik T / C temperature signal, an Inner T / C temperature signal, an over-temperature T / C temperature signal, an external Profile T / C temperature signal, and an over-temperature protection circuit.

[0048] The actual test results are as follows:

[0049] Table I, Breakdown of Heating Power for Each Zone of the Vertical Furnace Heating Element at 1100℃ (Actual Testing):

[0050] Set temperature: 1100 °C Rated voltage (V) Rated current (A) Rated power (KVA) Matching power (KVA) Actual output power (KVA) BTM (bottom) 98 125 12.25 51% 6.2475 CTR1 (middle bottom) 34 150 5.1 34% 1.734 CTR2 (middle) 64 175 11.2 30% 3.36 CTR3 (middle top) 48 125 6 33% 1.98 TPO (top) 72 125 9 42% 3.78

[0051] This means that the heating wires in the top and bottom zones of the heating element suffer the most severe losses. Therefore, in this embodiment, a non-contact electric field strength detector of 300 amps is installed at the top of the heating element near the TOP zone and at the bottom of the heating element near the BTM zone, respectively.

[0052] Example 1 (Heating element life monitoring), such as Figure 2 and Figure 3 As shown, a heating element 1 is installed inside the furnace, and an electric field strength detector 300 is installed at the non-contact electric field strength detector mounting position 4. 2-4 electric field strength detectors 300 are installed at each non-contact electric field strength detector mounting position 4 (adjusted according to the actual situation); there is a heating wire deformation point 5 on the heating wire 2.

[0053] The heating wire 2 and the furnace tube 3 are located on the same concentric circle, and can be regarded as parallel plates. According to the electric field formula of parallel plates, E=U / D (E, electric field strength between two points; U, potential difference, which is the voltage across the heating wire; D, distance, which in this embodiment is the distance between the heating wire and the furnace tube, and changes with the aging of the heating element).

[0054] Because the heating wire is voltaged at both ends, a fixed electric field is formed on the outer wall of the furnace tube. The electric field strength E is measured by a non-contact electric field strength detector. U is a fixed value, and D changes with time. Let the initial value of D be D0 (D0≈30mm for horizontal furnace, D0≈20mm for vertical furnace), and the value of D after changing with time be Dn (n≥1). D0-Dn=Dx=5mm is the warning limit, and D0-Dn=Dx=3mm is the safety limit.

[0055] like Figure 3As shown in the figure, the PLC controller 100 writes operation logic, and according to the formula E=U / D, an operation is performed at a certain time to obtain a Dx, and a warning limit and a safety limit of the "Dx" are set, the warning limit and the safety limit are triggered, and the alarm 500 is a distance alarm 501;

[0056] The alarm alarms at different levels, and the PLC controller 100 outputs a signal to the PC 600, and the PC 600 outputs a signal to the EAP system 700 to switch the equipment state, if the warning limit is triggered, the equipment state is switched to H-ENG (waiting for an engineer to confirm), the operating equipment can be appropriately relaxed to PM processing after the equipment operation is completed, and the non-operating equipment is directly processed. PM, the safety limit is triggered, and the equipment state is switched to DOWN (down), and the operating equipment is processed after the product passes through the recipe main step, and the non-operating equipment is directly processed. The time when the warning limit and the safety limit are reached determines that the heating body life has reached.

[0057] In embodiment 2, the difference from embodiment 1 is that the alarm 500 is a time alarm 502, a program is written in the PLC controller 100, the time T1 of Dx=5mm and the time T2 of Dx=3mm are set, and T2-T1≤5Min (heating wire rapidly ages), the time alarm 502 alarms and triggers, outputs a signal to the PLC controller 100, and outputs a signal to the over-temperature protection circuit 400 through the PLC controller 100, and the over-temperature protection circuit 400 cuts off the heating power supply of the heating body, and protects the silicon carbide tube.

[0058] In the description of the utility model, it needs to be explained that the terms "upper", "lower", "inner", "outer", "left", "right" and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the utility model product is used, or the orientation or positional relationship commonly understood by those skilled in the art, which is only for the convenience of describing the utility model and simplifying the description, and is not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model. In addition, the terms "first", "second" and the like are only used for differentiation and cannot be understood as indicating or implying relative importance. In the description of the utility model, it also needs to be explained that, unless otherwise explicitly specified and limited, the terms "set", "connect" and the like should be understood broadly, for example, "connect" can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

Claims

1. A heating element life monitoring device, characterized by, The PLC controller is electrically connected with a liquid crystal display, the electric field intensity detector is electrically connected with the PLC controller, the PLC controller is further electrically connected with an over-temperature protection circuit and is further signal-connected with a PC through an EAP system; the PLC controller is further electrically connected with an alarm; the alarm is a distance alarm or a time alarm.

2. A heating element life monitoring device according to claim 1, characterised in that, The PLC controller is electrically connected with a liquid crystal display, the electric field intensity detector is electrically connected with the PLC controller, the PLC controller is further electrically connected with an over-temperature protection circuit and is further signal-connected with a PC through an EAP system; the PLC controller is further electrically connected with an alarm; the alarm is a distance alarm or a time alarm.

3. The heating element life monitoring device of claim 1, wherein, The PLC controller is electrically connected with a liquid crystal display, the electric field intensity detector is electrically connected with the PLC controller, the PLC controller is further electrically connected with an over-temperature protection circuit and is further signal-connected with a PC through an EAP system; the PLC controller is further electrically connected with an alarm; the alarm is a distance alarm or a time alarm.

4. The heating element life monitoring device of claim 1, wherein, The PLC controller is electrically connected with a liquid crystal display, the electric field intensity detector is electrically connected with the PLC controller, the PLC controller is further electrically connected with an over-temperature protection circuit and is further signal-connected with a PC through an EAP system; the PLC controller is further electrically connected with an alarm; the alarm is a distance alarm or a time alarm.

5. The heating element life monitoring device of claim 1, wherein, The alarm is an electric field intensity alarm.

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