Temperature dynamic compensation method, medium and system for constant-temperature area of vertical high-temperature furnace body

Abstract

The invention discloses a temperature dynamic compensation method, medium and system for a constant-temperature area of a vertical high-temperature furnace body, and the method comprises the steps: obtaining the actual temperature in the furnace body and the infrared monitoring temperature outside the furnace body in the heating process of the vertical high-temperature furnace body; the temperature difference between the infrared monitoring temperature outside the furnace body and the actual temperature inside the furnace body is obtained, the temperature difference serves as a temperature compensation value, and a temperature compensation curve is formed through linear calculation between the adjacent temperature compensation values; and obtaining an actual set temperature curve according to the target temperature and the temperature compensation curve. According to the method, the temperature of the low-temperature area is increased through positive compensation in the heating process, the temperature value is gradually attenuated in the heating process, the temperature following performance of the whole constant-temperature area is maintained, the compensation value is continuously reduced in the heat preservation stage, and the temperature uniformity of the whole process stage is maintained through negative compensation.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of semiconductor furnace equipment, and in particular to a method, medium and system for dynamic temperature compensation in a constant temperature zone of a vertical high-temperature furnace. Background Art

[0002] High temperature oxidation and high temperature annealing are important processes in the production of third-generation semiconductor chips. The high temperature annealing process is used to activate the wafer after doping and repair lattice damage, and improve the trench mobility and field intensity peak effect at the corners in the manufacture of trench MOSFET. The high temperature oxidation process can generate an oxide film on the surface of the wafer to form a gate oxide layer. These two processes are extremely sensitive to the accuracy of process temperature control. Since the oxidation and annealing equipment processes more than 50 wafers in one furnace, the temperature uniformity of the constant temperature zone has a very important influence on the uniformity between wafers. The process temperature of the oxidation and annealing process is very high. The oxidation process of SiC material wafers can reach up to 1500℃, and the maximum temperature of the annealing process can reach 2000℃. Therefore, a layer of heat insulation material is usually wrapped around the process furnace tube and the bottom to prevent the external temperature from being too high while maintaining the internal high temperature.

[0003] In order to increase production, high-temperature furnace tube equipment currently usually adopts rapid heating technology, and controls the internal temperature through three-stage heaters to maintain the temperature of the entire constant temperature zone, which can support the processing of more than 50 wafers at a time. Due to the high temperature and cleanliness requirements, this type of equipment cannot use thermocouples for temperature acquisition for a long time, and instead uses non-contact infrared pyrometer temperature measurement, resulting in a difference between the measured temperature and the actual temperature in the reaction chamber. At present, the common practice is to insert a temperature calibration thermocouple externally before the formal process, calibrate the actual temperature with the infrared pyrometer measured temperature, and form a compensation value. However, due to the existence of the insulation layer, when the furnace tube is heated, the temperature of some areas is absorbed by the insulation layer and the temperature of this area will rise slowly; during the insulation stage, the insulation layer will cause the temperature of this part of the area to continue to rise, and the internal temperature uniformity will deteriorate. One or several fixed compensation values ​​cannot meet the needs. At present, some equipment on the market adopts unreasonable temperature control strategies, resulting in poor temperature uniformity in some areas, and the actual temperature in the constant temperature stage is constantly changing, resulting in poor product quality. Summary of the invention

[0004] In view of the technical problems existing in the prior art, the present invention provides a method, medium and system for dynamic temperature compensation in a constant temperature zone of a vertical high-temperature furnace for maintaining temperature uniformity in the entire process stage.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0006] A method for dynamic temperature compensation of a constant temperature zone of a vertical high-temperature furnace comprises the following steps:

[0007] During the heating process of the vertical high-temperature furnace, the actual temperature inside the furnace and the monitored temperature outside the furnace are obtained, and the temperature difference between the monitored temperature outside the furnace and the actual temperature inside the furnace is obtained, and the temperature difference is used as a temperature compensation value;

[0008] A temperature compensation curve is formed by linear calculation between adjacent temperature compensation values;

[0009] The actual set temperature curve is obtained based on the target temperature and the temperature compensation curve.

[0010] Preferably, during the heating process of the vertical high-temperature furnace, the actual temperatures at different positions inside the furnace and the corresponding monitored temperatures at different positions outside the furnace are acquired to obtain temperature compensation values ​​at different positions.

[0011] Preferably, after obtaining the temperature compensation values ​​at different positions, the temperatures at different positions of the furnace body are independently controlled according to the corresponding temperature compensation values.

[0012] Preferably, the vertical high-temperature furnace heating includes four stages, namely, a preheating stage, a rapid heating stage, a slow heating stage and a heat preservation stage; wherein in different stages, the temperature compensation curve is dynamically attenuated to dynamically compensate the temperature.

[0013] Preferably, for the lower area of ​​the furnace body, the temperature compensation curve is added with the dynamic attenuation coefficient K to form a final temperature compensation curve.

[0014] Preferably, for the lower area of ​​the furnace body, the dynamic attenuation coefficient K gradually decreases as the temperature rises during the preheating stage, the rapid heating stage and the slow heating stage; the dynamic attenuation coefficient K increases to a preset value when entering the insulation stage.

[0015] Preferably, the actual temperature inside the furnace body is obtained by a temperature-calibrating thermocouple; and the monitored temperature outside the furnace body is obtained by an infrared pyrometer.

[0016] The present invention also discloses a computer program product, comprising a computer program, wherein the computer program executes the steps of the method described above when executed by a processor.

[0017] The present invention further discloses a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described above are executed.

[0018] The present invention also discloses a vertical high-temperature furnace constant temperature zone temperature dynamic compensation system, comprising a memory and a processor connected to each other, wherein the memory stores a computer program, and when the computer program is run by the processor, the steps of the method described above are executed.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] The present invention aims at the problems that the temperature of some areas of conventional high-temperature furnace tube equipment rises slowly during heating, the temperature continues to rise during the constant temperature stage, and the internal temperature uniformity deteriorates. A dynamic compensation control method is proposed. This method can increase the temperature of the low-temperature area through positive compensation during the heating process, and gradually attenuate the temperature value during the heating process to maintain the temperature tracking of the entire constant temperature zone. The compensation value is continuously reduced during the insulation stage, and the temperature uniformity of the entire process stage is maintained through negative compensation. This method can maintain the actual temperature uniformity of the constant temperature zone during the heating process at ±15°C; the actual temperature uniformity of the constant temperature zone during the insulation stage is maintained at ±1°C, and the duration is more than 1 hour. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the temperature compensation curve of the present invention in an embodiment.

[0022] Figure 2 It is an example diagram of the temperature compensation curve of the present invention in a specific application.

[0023] Figure 3 This is a graph showing the actual temperature setting in an embodiment of the present invention.

[0024] Figure 4 1 and 1 are heating effect diagrams of the present invention; (a) is a heating effect diagram without using dynamic compensation; (b) is a heating effect diagram with using dynamic compensation.

[0025] Figure 5 This is the temperature compensation control block diagram of the present invention.

[0026] Figure 6 It is a schematic diagram of the arrangement of the infrared pyrometer and the temperature calibration thermocouple of the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0028] like Figure 5-Figure 6 As shown, the method for dynamic temperature compensation in the constant temperature zone of a vertical high-temperature furnace provided by the embodiment of the present invention comprises the steps of:

[0029] During the heating process of the vertical high-temperature furnace, the actual temperature inside the furnace is obtained by a temperature calibration thermocouple and the monitored temperature outside the furnace is obtained by an infrared pyrometer, and the temperature difference between the monitored temperature outside the furnace and the actual temperature inside the furnace is obtained, and the temperature difference is used as a temperature compensation value;

[0030] A temperature compensation curve is formed by linear calculation between adjacent temperature compensation values;

[0031] The actual set temperature curve is obtained based on the target temperature and the temperature compensation curve.

[0032] The present invention forms different temperature compensation values ​​according to different process temperatures, thereby forming a temperature compensation table. A temperature compensation curve can be formed by linear calculation between two points. The target temperature is added with the compensation value to obtain the actual set temperature curve, thereby realizing temperature compensation and ensuring temperature accuracy.

[0033] In a specific embodiment, during the heating process of the vertical high-temperature furnace, the actual temperature at different positions inside the furnace and the corresponding monitored temperature at different positions outside the furnace are obtained to obtain temperature compensation values ​​at different positions. After obtaining the temperature compensation values ​​at different positions, the temperatures at different positions of the furnace are independently controlled according to the corresponding temperature compensation values.

[0034] In a specific embodiment, the vertical high-temperature furnace body heating includes four stages, namely, the preheating stage, the rapid heating stage, the slow heating stage and the heat preservation stage; wherein at different stages, the temperature compensation curve is dynamically attenuated to dynamically compensate the temperature. For the lower area of ​​the furnace body, the temperature compensation curve is added with the dynamic attenuation coefficient K to form the final temperature compensation curve. Specifically, the dynamic attenuation coefficient K gradually decreases as the temperature rises in the preheating stage, the rapid heating stage and the slow heating stage; the dynamic attenuation coefficient K increases to a preset value when entering the heat preservation stage.

[0035] In view of the problems that, when heating up, the temperature of some areas of conventional high-temperature furnace tube equipment rises slowly, the temperature continues to rise in the constant temperature stage, and the internal temperature uniformity deteriorates, the method of the present invention increases the temperature of the low-temperature area through positive compensation in the heating stage, and gradually attenuates the temperature value during the heating process to maintain the temperature followability of the entire constant temperature zone, continuously reduces the compensation value in the insulation stage, and maintains the temperature uniformity of the entire process stage through negative compensation.

[0036] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0037] First, the actual temperature inside the furnace is detected by inserting a temperature-calibrated thermocouple externally. The thermocouple can measure the temperatures at the top, middle and bottom of the furnace body. The temperature is raised to the process temperature, and the compensation value is used to make the actual internal temperature close to the infrared monitoring temperature. Different temperature compensation values ​​are formed according to different process temperatures, thereby forming a temperature compensation table (as shown in Table 1). A temperature compensation curve can be formed through linear calculation between two points. The target temperature plus the compensation value will give the actual set temperature curve.

[0038] Table 1 Mapping relationship between temperature and compensation value at any measurement point

[0039] upper temperature zone Medium temperature zone Lower temperature zone Target temperature (℃) <![CDATA[T sv Previous]]> <![CDATA[T sv China]]> <![CDATA[T sv Next]]> Infrared detection temperature (℃) <![CDATA[T pv Previous]]> <![CDATA[T pv > in <![CDATA[T pv Next]]> Calibration thermocouple temperature (℃) <![CDATA[T tc Previous]]> <![CDATA[T tc > <![CDATA[T tc Next]]> Compensation value (℃) <![CDATA[T pv Upper-T tc Previous]]> <![CDATA[T pv Medium-T tc Medium]]> <![CDATA[T pv Down-T tc Next]]> Set temperature(℃) <![CDATA[T sv Up+(T pv Upper-T tc Previous)]]> <![CDATA[T sv Medium+(T pv Medium-T tc (in Chinese)]]> <![CDATA[T sv Down+(T pv Down-T tc Next)]]>

[0040] For example: temperature compensation is performed at 500°C, 900°C, 1200°C, 1500°C and 1700°C respectively, and a fixed temperature compensation value can be obtained at each temperature point (as shown in Table 2 and Figure 1 A linear calculation is performed between two adjacent temperature points to obtain a compensation curve (such as Figure 2 ), for example, the lower compensation value at 500°C is 60°C, and the lower compensation value at 900°C is 30°C, then the compensation value at 700°C is (60-30) / (900-500)*(700-500)=15°C.

[0041] Table 2 Temperature compensation values ​​of multiple measurement points

[0042]

[0043] However, in the actual heating process, due to the insulation layer, the lower area close to the insulation layer will heat up slowly. During the insulation stage, the actual temperature of the reaction chamber will slowly rise again. At this time, it is necessary to further adopt a continuously decaying dynamic compensation value to maintain the temperature.

[0044] Specifically, the entire control process is divided into four control stages: preheating stage, rapid heating stage, slow heating stage and heat preservation stage;

[0045] like Figure 2 As shown, after obtaining multiple groups of compensation values, the attenuation coefficient K is added during the insulation process to form a final compensation curve.

[0046] Table 3 Temperature compensation values ​​of multiple measurement points after adding the lower temperature zone attenuation coefficient

[0047]

[0048] like Figure 3 As shown, in the preheating stage, a set of fixed compensation values ​​is used to heat to 500°C. This set of compensation values ​​needs to be able to stabilize the actual temperature of the entire constant temperature zone reaction chamber at 500°C at a faster speed; then a slope compensation is formed by the set of fixed compensation values ​​and the temperature compensation value of the process temperature insulation section, and the compensation value change rate is modified on the set of compensation values ​​through the proportional coefficient.

[0049] In the rapid heating stage, since the temperature of some areas (especially the bottom area) rises slowly and has poor follow-up performance, the compensation value decays at a slow rate (for example, K is 0.8) to maintain the temperature of this area.

[0050] In the slow heating stage, since the overall temperature rises at this time, the area where the temperature rises slowly is weakened by the insulation layer, and the compensation value decays faster (for example, K is 0.5).

[0051] During the process temperature insulation stage, as the insulation layer begins to dissipate heat, the temperature of this area continues to rise. The compensation value will control the temperature compensation value to slowly decay (for example, K is 1.2 because the compensation value is a negative value) until a fixed negative compensation value is reached to maintain the process temperature.

[0052] The final measured effect is as follows Figure 4 As shown in a and 4b, the temperature control effect with dynamic compensation value is obvious in the whole temperature section. The three temperature zones in the low temperature section have better followability. At high temperature, the uniformity of the three temperature zones in the whole constant temperature section can be significantly improved.

[0053] This method can maintain the actual temperature uniformity of the constant temperature zone at ±15°C during the heating process; during the insulation stage, the actual temperature uniformity of the constant temperature zone can be maintained at ±1°C for more than 1 hour.

[0054] The embodiment of the present invention further discloses a computer program product, including a computer program, which executes the steps of the above method when executed by a processor. The embodiment of the present invention further discloses a computer-readable storage medium, on which a computer program is stored, which executes the steps of the above method when executed by a processor. The embodiment of the present invention further discloses a temperature dynamic compensation system for a constant temperature zone of a vertical high-temperature furnace, including a memory and a processor connected to each other, on which a computer program is stored, which executes the steps of the above method when executed by a processor.

[0055] The present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned method embodiment when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. Computer-readable storage media include: any entity or device that can carry computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. The memory is used to store computer programs and / or modules, and the processor implements various functions by running or executing computer programs and / or modules stored in the memory, and calling data stored in the memory. The memory may include high-speed random access memory and may also include non-volatile memory, such as a hard disk, an internal memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0056] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A method for dynamic temperature compensation in a constant temperature zone of a vertical high temperature furnace, characterized in that: Includes steps: During the heating process of the vertical high-temperature furnace, the actual temperature inside the furnace and the monitored temperature outside the furnace are obtained, and the temperature difference between the monitored temperature outside the furnace and the actual temperature inside the furnace is obtained, and the temperature difference is used as a temperature compensation value; A temperature compensation curve is formed by linear calculation between adjacent temperature compensation values; The actual set temperature curve is obtained based on the target temperature and the temperature compensation curve.

2. The method for dynamic temperature compensation of a constant temperature zone of a vertical high temperature furnace according to claim 1, characterized in that: During the heating process of the vertical high-temperature furnace, the actual temperatures at different positions inside the furnace and the corresponding monitored temperatures at different positions outside the furnace are obtained to obtain temperature compensation values ​​at different positions.

3. The method for dynamic temperature compensation of a constant temperature zone of a vertical high temperature furnace according to claim 2, characterized in that: After obtaining the temperature compensation values ​​at different positions, the temperatures at different positions of the furnace body are independently controlled according to the corresponding temperature compensation values.

4. The method for dynamic temperature compensation in a constant temperature zone of a vertical high temperature furnace according to claim 1, 2 or 3, characterized in that: The vertical high-temperature furnace body heating includes four stages, namely, preheating stage, rapid heating stage, slow heating stage and insulation stage; In different stages, the temperature compensation curve is dynamically attenuated to dynamically compensate for the temperature.

5. The method for dynamic temperature compensation of a constant temperature zone of a vertical high temperature furnace according to claim 4, characterized in that: For the lower area of ​​the furnace, the temperature compensation curve is added with the dynamic attenuation coefficient K to form the final temperature compensation curve.

6. The method for dynamic temperature compensation of a constant temperature zone of a vertical high temperature furnace according to claim 5, characterized in that: For the lower area of ​​the furnace body, the dynamic attenuation coefficient K gradually decreases as the temperature rises during the preheating stage, the rapid heating stage and the slow heating stage; the dynamic attenuation coefficient K increases to a preset value when entering the insulation stage.

7. The method for dynamic temperature compensation in a constant temperature zone of a vertical high temperature furnace according to claim 1, 2 or 3, characterized in that: The actual temperature inside the furnace is obtained through a temperature-calibrated thermocouple; the monitored temperature outside the furnace is obtained through an infrared pyrometer.

8. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are performed.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the computer program performs the steps of the method according to any one of claims 1 to 7.

10. A vertical high-temperature furnace constant temperature zone temperature dynamic compensation system, comprising a memory and a processor connected to each other, wherein a computer program is stored in the memory, characterized in that: When the computer program is executed by a processor, the computer program performs the steps of the method according to any one of claims 1 to 7.

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