Optimization method for improving temperature uniformity of hot plate

Abstract

The invention discloses an optimization method for improving the temperature uniformity of a hot plate. The optimization method comprises the following steps that S1, grooves are formed in the inner ring and the outer ring of a heat conduction plate according to different intervals; s2, splitting the armored electric heating wire into two electric heating wires, and respectively embedding the two electric heating wires into an inner ring and an outer ring of the heat conducting plate; s3, carrying out preliminary fast heating on the inner and outer ring electric heating wires according to the same rated power; s4, performing synchronous slow heating on the inner and outer ring electric heating wires according to different initial powers; and S5, controlling the power of the inner and outer heating wires according to the temperature feedback until the target temperature is reached. According to the technical scheme, the armored electric heating wire is divided into the two electric heating wires, the grooves are formed in the inner ring and the outer ring of the heat conduction plate at different intervals to control the heat source density, the two electric heating wires are embedded into the inner ring and the outer ring of the heat conduction plate respectively, and then the temperature of the inner ring and the temperature of the outer ring of the heat conduction plate tend to be close by controlling the heating curves of the two electric heating wires respectively. And the temperature uniformity of the heat-conducting disc is improved.

Description

Technical Field

[0001] The invention relates to the technical field of heaters, and in particular to an optimization method for improving the temperature uniformity of a hot plate. Background Art

[0002] In the wafer manufacturing process, dry stripping (plasma ashing) has many advantages over wet stripping, such as no pollution, high speed, thorough stripping, and precise control, making it an indispensable and important process in the entire production and manufacturing. With the improvement of semiconductor manufacturing process level and the further reduction of feature size, the requirements for plasma process stability and precise control are getting higher and higher. Temperature is one of the most important factors affecting the rate and uniformity of plasma stripping. Accurately controlling the temperature of the wafer is an important guarantee for process stability.

[0003] At present, induction coils are mostly used to heat the wafers on the substrate. In the semiconductor processing process, under the premise of appropriate temperature, the uniformity of the wafer temperature will directly determine the speed and quality of wafer processing, and the uneven temperature between the center and the edge of the wafer will make the wafer consistency worse, the defects more, and the yield worse when processing the wafer, which will lead to the low quality of the semiconductor or semiconductor chip manufactured using the wafer. Therefore, the induction coil needs to ensure the uniformity of the temperature distribution on the wafer when heating.

[0004] Chinese patent document CN115632013B discloses a "wafer heating device". It includes: a substrate, the substrate includes a first surface, the first surface includes a wafer bearing area for placing a wafer; a heating component, the heating component includes an induction coil, the induction coil includes at least: a first coil distributed in a ring and a second coil electrically connected to the first coil and located inside the first coil, the second coil includes a plurality of turns; with the orthographic projection of the induction coil on the first surface as a reference, the first coil includes at least a plurality of turns and the orthographic projection of the plurality of turns covers the wafer bearing area, the distance between adjacent turns of the first coil is less than the distance between adjacent turns in the second coil, so that the heat generated by the first coil is more uniform. The above technical solution changes the coil layout in the vertical direction, increases the volume and has high heat dissipation. Summary of the invention

[0005] The present invention mainly solves the technical problem that the original technical solution changes the coil layout in the vertical direction, increases the volume and has high heat loss, and provides an optimization method for improving the temperature uniformity of the heat plate. The armored heating wire is split into two heating wires, and grooves are respectively made in the inner and outer circles of the heat conducting plate at different intervals to control the heat source density. The two heating wires are respectively embedded in the inner and outer circles of the heat conducting plate, and the heating curves of the two heating wires are respectively controlled to make the temperatures of the inner and outer circles of the heat conducting plate close to each other, thereby improving the temperature uniformity of the heat conducting plate.

[0006] The above technical problem of the present invention is mainly solved by the following technical solution: The present invention comprises the following steps: S1. slotting the inner and outer circles of the heat conducting plate at different intervals; S2. Split the armored heating wire into two heating wires and embed them into the inner and outer circles of the heat conducting plate respectively; S3. Perform preliminary rapid heating of the inner and outer ring heating wires at the same rated power; S4. The inner and outer heating wires are heated synchronously and slowly according to different initial powers; S5. Control the power of the inner and outer heating wires according to the temperature feedback until the target temperature is reached.

[0007] The armored heating wire is split into two heating wires, grooves are cut at different intervals on the inner and outer circles of the heat conducting plate to control the heat source density, the two heating wires are respectively embedded in the inner and outer circles of the heat conducting plate, and the heating curves of the two heating wires are controlled separately to make the temperatures of the inner and outer circles of the heat conducting plate close, thereby improving the temperature uniformity of the heat conducting plate.

[0008] Preferably, the S1 specifically includes opening two heating wire installation grooves on the inner and outer circles of the heat conducting plate respectively, and the spacing between the heating wire installation grooves of the inner circle of the heat conducting plate is smaller than the spacing between the heating wire installation grooves of the outer circle of the heat conducting plate.

[0009] Preferably, the heating wire installation groove of the inner circle of the heat conducting plate and the heating wire installation groove of the outer circle of the heat conducting plate are spirally arranged around the same center, and the innermost diameter of the heating wire installation groove of the outer circle of the heat conducting plate is larger than the outermost diameter of the heating wire installation groove of the inner circle of the heat conducting plate.

[0010] Preferably, a center temperature sensor is provided at the center of the heating wire mounting groove of the inner circle of the heat conducting plate, a plurality of inner circle edge temperature sensors are provided between the heating wire mounting groove of the inner circle of the heat conducting plate and the heating wire mounting groove of the outer circle of the heat conducting plate, and a plurality of outer circle edge temperature sensors are provided at the outermost circle of the heating wire mounting groove of the outer circle of the heat conducting plate.

[0011] Preferably, the S2 splits the armored heating wire into two heating wires, and the two heating wires are respectively installed in the inner circle heating wire installation groove and the outer circle heating wire installation groove.

[0012] Preferably, the inner circle heating wire and the outer circle heating wire are of the same length and are connected to power sources respectively to work independently.

[0013] Preferably, the S3 specifically includes setting a threshold value for preliminary rapid heating according to the target temperature, and performing preliminary rapid heating on the inner and outer ring heating wires at the same rated power.

[0014] Preferably, the inner ring temperature is calculated by calculating the average value of the temperatures collected by the center temperature sensor and several inner ring edge temperature sensors, and the outer ring temperature is calculated by calculating the average value of the temperatures collected by several inner ring edge temperature sensors and several outer ring edge temperature sensors.

[0015] Preferably, the heating is stopped when the temperature of the inner ring reaches a threshold value for initial rapid heating, and when the temperature of the outer ring also reaches the threshold value for initial rapid heating, the inner and outer ring heating wires are synchronously and slowly heated according to different initial powers.

[0016] Preferably, the S5 collects the changes in the inner ring temperature and the outer ring temperature per unit time as the inner ring temperature rise and the outer ring temperature rise respectively. If the inner ring temperature rise is different from the outer ring temperature rise and does not exceed the rated power, the heating wire with lower temperature rise increases the power; if the inner ring temperature rise is different from the outer ring temperature rise and exceeds the rated power, the heating wire with higher temperature rise reduces the power; the loop feedback is performed until the inner ring temperature rise is the same as the outer ring temperature rise, and the initial power is updated according to the power at this time.

[0017] The beneficial effects of the present invention are as follows: by splitting the armored heating wire into two heating wires, slotting the inner and outer circles of the heat conducting plate at different intervals to control the heat source density, the two heating wires are respectively embedded in the inner and outer circles of the heat conducting plate, and then the heating curves of the two heating wires are respectively controlled so that the temperatures of the inner and outer circles of the heat conducting plate tend to be close, thereby improving the temperature uniformity of the heat conducting plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of the present invention.

[0019] Figure 2 It is a schematic diagram of a heating wire installation groove of a heat conducting plate of the present invention.

[0020] Figure 3 It is a schematic diagram of the completion of embedding an armored heating wire of the present invention.

[0021] In the figure, 1 is armored heating wire, and 2 is heat conducting plate. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the technical solution of the present invention is further described in detail below through embodiments and in combination with the accompanying drawings. It should be understood that the specific implementation method described here is only an optimal embodiment of the present invention, which is only used to explain the present invention and does not limit the scope of protection of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] The wafer heating plate is a device used in the coating and developing equipment to heat the wafer to a constant temperature. The heating core of the wafer heating plate is generally divided into mica type and armored heating wire type. This technology is an application design based on the embedded armored heating wire. The armored heating wire contains a resistance wire. The resistance wire is heated by loading current and voltage on the resistance wire. The heat generated by the resistance wire is conducted to the heat conduction plate of the wafer heating plate through heat conduction, thereby increasing the temperature of the heat conduction plate. The armored heating wire is then controlled by a temperature controller so that the heat conduction plate reaches the target temperature.

[0024] There are generally two ways to connect the armored heating wire and the heat conducting plate: casting and embedding. Among them, the armored heating wire and the heat conducting plate are cast into one piece. After the heating wire is energized, the temperature uniformity on the surface of the heat conducting plate is better. However, the casting method requires a casting mold and cannot be changed after the one-piece molding. If the armored heating wire is damaged, it will be scrapped as a whole, which will increase the cost of the casting method and is only suitable for large-scale processing. By milling the installation groove of the armored heating wire on the heat conducting plate, the method of pressing the armored heating wire into the groove is more flexible, which is more advantageous in small-batch processing. In theory, the more heating wires are arranged on the heat conducting plate, the more uniform the temperature on the surface of the heat conducting plate will be. However, due to the error of the resistance wire in the armored heating wire during processing, there will be certain differences in temperature at different positions of the same heating wire at the same time. The longer the length of the heating wire, the more obvious the difference will be. When this temperature difference is transmitted to the surface of the heat conducting plate, it will be amplified, making the temperature uniformity of the heat conducting plate fail to meet the requirements.

[0025] The resistance wire is heated by loading current and voltage on it, and the heat generated by the resistance wire is transferred to the heat conducting plate of the wafer heating disk through heat conduction, thereby increasing the temperature of the heat conducting plate. The armored heating wire is then controlled by a temperature controller so that the heat conducting plate reaches the target temperature.

[0026] There are generally two ways to connect the armored heating wire and the heat conducting plate: casting and embedding. Among them, the armored heating wire and the heat conducting plate are cast into one piece. After the heating wire is energized, the temperature uniformity on the surface of the heat conducting plate is better. However, the casting method requires a casting mold and cannot be changed after the one-piece molding. If the armored heating wire is damaged, it will be scrapped as a whole, which will increase the cost of the casting method and is only suitable for large-scale processing. By milling the installation groove of the armored heating wire on the heat conducting plate, the method of pressing the armored heating wire into the groove is more flexible, which is more advantageous in small-batch processing. In theory, the more heating wires are arranged on the heat conducting plate, the more uniform the temperature on the surface of the heat conducting plate will be. However, due to the error of the resistance wire in the armored heating wire during processing, there will be certain differences in temperature at different positions of the same heating wire at the same time. The longer the length of the heating wire, the more obvious the difference will be. When this temperature difference is transmitted to the surface of the heat conducting plate, it will be amplified, making the temperature uniformity of the heat conducting plate fail to meet the requirements.

[0027] The present invention mainly adopts the following technical solutions: Taking the 8-inch wafer heating plate commonly used in the market as an example, an armored heating wire of about 3 to 4 meters long needs to be arranged in a wafer heating plate. Such a long armored heating wire not only increases the processing difficulty but also increases the error of the heating wire itself. Therefore, it can be considered to split the armored heating wire into two heating wires without changing the total length. At the same time, there is a heat concentration effect in the actual use of the wafer heating plate, which causes the temperature of the inner circle to be higher than the temperature of the outer circle after the wafer is placed on it. Therefore, after changing to a two-heating wire solution, grooves can be respectively opened in the inner and outer circles of the heat conducting plate, and the two heating wires can be respectively embedded in the inner and outer circles of the heat conducting plate, and then the two heating wires can be controlled separately to make the temperatures of the inner and outer circles of the heat conducting plate close, thereby improving the temperature uniformity of the heat conducting plate.

[0028] The present invention has the following effects: (1) The processing difficulty of the armored heating wire is reduced.

[0029] (2) The processing error of the armored heating wire itself is reduced.

[0030] (3) The heat conducting plate is divided into two areas and controlled separately, which provides temperature uniformity of the wafer heating plate.

[0031] (4) The structure is flexible and can be adjusted according to different customer needs.

[0032] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe the operations (or steps) as sequential processes, many of the operations (or steps) therein can be implemented in parallel, concurrently, or simultaneously. In addition, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but can also have additional steps not included in the drawings; the process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0033] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0034] Embodiment: This embodiment is an optimization method for improving the temperature uniformity of the hot plate, such as Figure 1 As shown, the following steps are included: S1. Slot the inner and outer circles of the heat conducting plate at different intervals, such as Figure 2 As shown, specifically, two heating wire installation grooves are respectively opened on the inner and outer circles of the heat conducting plate 2, and the spacing between the inner circle heating wire installation grooves is smaller than that between the outer circle heating wire installation grooves. The inner circle heating wire installation groove and the outer circle heating wire installation groove are spirally arranged around the same center, and the innermost diameter of the outer circle heating wire installation groove is larger than the outermost diameter of the inner circle heating wire installation groove.

[0035] A center temperature sensor is provided at the center of the inner circle heating wire installation groove, a plurality of inner circle edge temperature sensors are provided between the inner circle heating wire installation groove and the outer circle heating wire installation groove, and a plurality of outer circle edge temperature sensors are provided at the outermost circle of the outer circle heating wire installation groove.

[0036] S2. Figure 3 As shown, the armored heating wire 1 is split into two heating wires and respectively embedded in the inner and outer circles of the heat conducting plate. The armored heating wire is split into two heating wires, and the two heating wires are respectively installed in the inner circle heating wire installation groove and the outer circle heating wire installation groove. The inner circle heating wire and the outer circle heating wire have the same length and are connected to the power supply to work independently.

[0037] S3. Perform preliminary rapid heating on the inner and outer ring heating wires at the same rated power, specifically including setting a threshold for preliminary rapid heating according to the target temperature, and performing preliminary rapid heating on the inner and outer ring heating wires at the same rated power. Calculate the average value of the temperatures collected by the center temperature sensor and several inner ring edge temperature sensors as the inner ring temperature, and calculate the average value of the temperatures collected by several inner ring edge temperature sensors and several outer ring edge temperature sensors as the outer ring temperature. When the inner ring temperature reaches the threshold for preliminary rapid heating, stop heating. When the outer ring temperature also reaches the threshold for preliminary rapid heating, the inner and outer ring heating wires perform synchronous slow heating at different initial powers.

[0038] S4. The inner and outer ring heating wires are heated synchronously and slowly according to different initial powers. The changes in the inner ring temperature and the outer ring temperature per unit time are collected as the inner ring temperature rise and the outer ring temperature rise respectively. If the inner ring temperature rise is different from the outer ring temperature rise and does not exceed the rated power, the heating wire with the lower temperature rise increases the power; if the inner ring temperature rise is different from the outer ring temperature rise and exceeds the rated power, the heating wire with the higher temperature rise reduces the power; the feedback loop is repeated until the inner ring temperature rise is the same as the outer ring temperature rise, and the initial power is updated according to the power at this time.

[0039] S5. Control the power of the inner and outer ring heating wires according to temperature feedback until the target temperature is reached. The armored heating wire is split into two heating wires, and the heat source density is controlled by slotting the inner and outer rings of the heat conducting plate at different intervals. The two heating wires are respectively embedded in the inner and outer rings of the heat conducting plate, and the heating curves of the two heating wires are respectively controlled to make the temperatures of the inner and outer rings of the heat conducting plate close to each other, thereby improving the temperature uniformity of the heat conducting plate.

[0040] Example 2 The Lagrange piecewise linear interpolation method is used to provide a certain temperature compensation for the entire interval to ensure that the final target temperature meets the process requirements, including the following steps: S1. Slot the inner and outer circles of the heat conducting plate at different intervals, such as Figure 2 As shown, specifically, two heating wire installation grooves are respectively opened on the inner and outer circles of the heat conducting plate, and the spacing between the inner circle heating wire installation grooves is smaller than that between the outer circle heating wire installation grooves. The inner circle heating wire installation groove and the outer circle heating wire installation groove are spirally arranged around the same center, and the innermost diameter of the outer circle heating wire installation groove is larger than the outermost diameter of the inner circle heating wire installation groove. A center temperature sensor is provided at the center of the inner circle heating wire installation groove, a plurality of inner circle edge temperature sensors are provided between the inner circle heating wire installation groove and the outer circle heating wire installation groove, and a plurality of outer circle edge temperature sensors are provided at the outermost circle of the outer circle heating wire installation groove.

[0041] S2. Figure 3 As shown, the armored heating wire is split into two heating wires and respectively embedded in the inner and outer circles of the heat conducting plate. The armored heating wire is split into two heating wires, and the two heating wires are respectively installed in the inner circle heating wire installation groove and the outer circle heating wire installation groove. The inner circle heating wire and the outer circle heating wire have the same length and are connected to the power supply to work independently.

[0042] S3. Perform preliminary rapid heating on the inner and outer ring heating wires at the same rated power, specifically including setting a threshold for preliminary rapid heating according to the target temperature, and performing preliminary rapid heating on the inner and outer ring heating wires at the same rated power. Calculate the average value of the temperatures collected by the center temperature sensor and several inner ring edge temperature sensors as the inner ring temperature, and calculate the average value of the temperatures collected by several inner ring edge temperature sensors and several outer ring edge temperature sensors as the outer ring temperature. When the inner ring temperature reaches the threshold for preliminary rapid heating, stop heating until the outer ring temperature also reaches the threshold for preliminary rapid heating.

[0043] S4. Continue to perform preliminary fast heating at the same rated power, and then select the common process temperature in the common temperature range of 40°C to 280°C as the node (basically evenly distributed) for temperature compensation. The software uses Lagrange piecewise linear interpolation to give a certain temperature compensation for the entire interval to ensure that the deviation between the actual wafer temperature and the process set temperature is within the engineering requirements, thereby ensuring the stability of the process.

[0044] In the common ashing process temperature range of 40-280℃, select reasonable temperature nodes, such as: x0≤x1≤x2≤x3≤x4≤x5≤x6≤x7…xn, and use sensors to simulate temperature measurement to give corresponding temperature compensation values ​​for the nodes: y0, y1, y2, y3, y4, y5, y6, y7…yn. Through the Lagrange piecewise linear interpolation method, the compensation temperature LA(x) of any temperature x between 40℃-280℃ can be obtained.

[0045] In actual use, 8 temperature nodes can be selected for compensation, such as 40, 70, 90, 120, 150, 200, 250, 280°C and other common process temperatures, and then the above method can be used to give temperature compensation for other points through software control.

[0046] S5. Control the power of the inner and outer ring heating wires according to temperature feedback until the target temperature is reached. The armored heating wire is split into two heating wires, and the heat source density is controlled by slotting the inner and outer rings of the heat conducting plate at different intervals. The two heating wires are respectively embedded in the inner and outer rings of the heat conducting plate, and the heating curves of the two heating wires are respectively controlled to make the temperatures of the inner and outer rings of the heat conducting plate close to each other, thereby improving the temperature uniformity of the heat conducting plate.

[0047] Example 3 The wafer heating plates on the market are mainly 8 inches and 12 inches. Here we take the actual invention of the 8-inch wafer heating plate armored heating wire arrangement as an example.

[0048] The main heating components of the wafer heating plate can be divided into two main parts: the heat conducting plate and the armored heating wire.

[0049] The heat conducting plate is generally made of aluminum alloy materials such as 6061 and 6063, and is subjected to hard anodized surface treatment. The flatness of the upper surface of the heat conducting plate is ≤0.03, and the inner and outer ring heating wire installation grooves are milled on the lower surface. The installation grooves can be adjusted according to actual requirements. In the present invention, the lengths of the inner and outer ring heating wire installation grooves are relatively consistent, both about 1.8 meters. The armored heating wire includes a stainless steel 316L casing, an 8020 nickel-chromium alloy resistance wire, and an insulating layer.

[0050] During processing, it is necessary to first open two heating wire installation grooves on the inner and outer circles of the heat conducting plate respectively, and then embed the two armored heating wires into the heat conducting plate respectively to form a heating unit; the two heating wires are independent of each other and can be connected to the power supply for work separately; in order to realize the independent operation of the two heating wires, it is necessary to install a temperature sensor in the inner and outer circles of the heat conducting plate respectively for temperature detection, and then connect the power lines of the two heating wires to two temperature controllers for control.

[0051] In actual operation, since heat will gather in the middle, and the periphery will dissipate more heat due to the larger contact area with the air, the temperature in the middle of the disk will be higher than the temperature around it. At this time, we can reduce the target temperature of the inner circle heating wire corresponding to the thermostat to reduce the temperature of the inner circle, or increase the target temperature of the outer circle heating wire corresponding to the thermostat to increase the temperature of the outer circle, so that the temperatures of the inner and outer circles tend to be consistent, and the overall temperature uniformity of the disk is improved. The specific control includes the following steps: S1. Slot the inner and outer circles of the heat conducting plate at different intervals, such as Figure 2 As shown, specifically, two heating wire installation grooves are respectively opened on the inner and outer circles of the heat conducting plate, and the spacing between the inner circle heating wire installation grooves is smaller than that between the outer circle heating wire installation grooves. The inner circle heating wire installation groove and the outer circle heating wire installation groove are spirally arranged around the same center, and the innermost diameter of the outer circle heating wire installation groove is larger than the outermost diameter of the inner circle heating wire installation groove.

[0052] A center temperature sensor is provided at the center of the inner circle heating wire installation groove, a plurality of inner circle edge temperature sensors are provided between the inner circle heating wire installation groove and the outer circle heating wire installation groove, and a plurality of outer circle edge temperature sensors are provided at the outermost circle of the outer circle heating wire installation groove.

[0053] S2. Figure 3 As shown, the armored heating wire is split into two heating wires and respectively embedded in the inner and outer circles of the heat conducting plate. The armored heating wire is split into two heating wires, and the two heating wires are respectively installed in the inner circle heating wire installation groove and the outer circle heating wire installation groove. The inner circle heating wire and the outer circle heating wire have the same length and are connected to the power supply to work independently.

[0054] S3. Perform preliminary rapid heating on the inner and outer ring heating wires at the same rated power, specifically including setting a threshold for preliminary rapid heating according to the target temperature, and performing preliminary rapid heating on the inner and outer ring heating wires at the same rated power. Calculate the average value of the temperatures collected by the center temperature sensor and several inner ring edge temperature sensors as the inner ring temperature, and calculate the average value of the temperatures collected by several inner ring edge temperature sensors and several outer ring edge temperature sensors as the outer ring temperature. When the inner ring temperature reaches the threshold for preliminary rapid heating, stop heating. When the outer ring temperature also reaches the threshold for preliminary rapid heating, the inner and outer ring heating wires perform synchronous slow heating at different initial powers.

[0055] S4. The inner and outer ring heating wires are heated synchronously and slowly according to different initial powers. The changes in the inner ring temperature and the outer ring temperature per unit time are collected as the inner ring temperature rise and the outer ring temperature rise respectively. If the inner ring temperature rise is different from the outer ring temperature rise and does not exceed the rated power, the heating wire with the lower temperature rise increases the power; if the inner ring temperature rise is different from the outer ring temperature rise and exceeds the rated power, the heating wire with the higher temperature rise reduces the power; the feedback loop is repeated until the inner ring temperature rise is the same as the outer ring temperature rise, and the initial power is updated according to the power at this time.

[0056] S5. Control the power of the inner and outer ring heating wires according to temperature feedback until the target temperature is reached. The armored heating wire is split into two heating wires, and the heat source density is controlled by slotting the inner and outer rings of the heat conducting plate at different intervals. The two heating wires are respectively embedded in the inner and outer rings of the heat conducting plate, and the heating curves of the two heating wires are respectively controlled to make the temperatures of the inner and outer rings of the heat conducting plate close to each other, thereby improving the temperature uniformity of the heat conducting plate.

[0057] Currently, this solution has been used on a 12-inch hot plate (6 zones). The difference from the above is that this hot plate is divided into 6 independent zones, each of which can operate independently, while the above solution is to embed two armored heating wires on the same heat-conducting aluminum plate; but the principles of the two solutions are the same, both of which use zone temperature control to improve the temperature uniformity of the hot plate.

[0058] The specific embodiments described herein are merely examples of the spirit of the present invention. The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that technicians in the technical field to which the present invention belongs can make various modifications or supplements to the described specific embodiments or replace them in a similar manner, but will not deviate from the spirit of the present invention or exceed the scope defined in the attached claims. For ordinary technicians in this field, multiple deformations and improvements can also be made without departing from the concept of the present invention. Therefore, the scope of protection of the patent of the present invention shall be based on the attached claims.

Claims

1. An optimization method for improving the temperature uniformity of a hot plate, characterized in that: The following steps are involved: S1. Slot the inner and outer circles of the heat conducting plate at different intervals; S2. Split the armored heating wire into two heating wires and embed them into the inner and outer circles of the heat conducting plate respectively; S3. Perform preliminary rapid heating of the inner and outer ring heating wires at the same rated power; S4. The inner and outer heating wires are heated synchronously and slowly according to different initial powers; S5. Control the power of the inner and outer heating wires according to the temperature feedback until the target temperature is reached.

2. The optimization method for improving the temperature uniformity of a hot plate according to claim 1, characterized in that: The S1 specifically includes opening two heating wire installation grooves on the inner and outer circles of the heat conducting plate respectively, and the spacing between the heating wire installation grooves of the inner circle of the heat conducting plate is smaller than the spacing between the heating wire installation grooves of the outer circle of the heat conducting plate.

3. The optimization method for improving the temperature uniformity of a hot plate according to claim 1, characterized in that: The heating wire installation groove of the inner circle of the heat conducting plate and the heating wire installation groove of the outer circle of the heat conducting plate are spirally arranged around the same center, and the innermost diameter of the heating wire installation groove of the outer circle of the heat conducting plate is larger than the outermost diameter of the heating wire installation groove of the inner circle of the heat conducting plate.

4. The optimization method for improving the temperature uniformity of a hot plate according to claim 2, characterized in that: A center temperature sensor is provided at the center of the heating wire installation groove of the inner circle of the heat conducting plate, a plurality of inner circle edge temperature sensors are provided between the heating wire installation groove of the inner circle of the heat conducting plate and the heating wire installation groove of the outer circle of the heat conducting plate, and a plurality of outer circle edge temperature sensors are provided at the outermost circle of the heating wire installation groove of the outer circle of the heat conducting plate.

5. The optimization method for improving the temperature uniformity of a hot plate according to claim 2, 3 or 4, characterized in that: The S2 splits the armored heating wire into two heating wires, and the two heating wires are respectively installed in the inner circle heating wire installation groove and the outer circle heating wire installation groove.

6. The optimization method for improving the temperature uniformity of a hot plate according to claim 5, characterized in that: The inner circle heating wire and the outer circle heating wire have the same length and are connected to power sources respectively to work independently.

7. The optimization method for improving the temperature uniformity of a hot plate according to claim 4, characterized in that: The S3 specifically includes setting a threshold value for preliminary rapid heating according to the target temperature, and performing preliminary rapid heating on the inner and outer ring heating wires at the same rated power.

8. The optimization method for improving the temperature uniformity of a hot plate according to claim 7, characterized in that: The average value of the temperatures collected by the circle center temperature sensor and several inner ring edge temperature sensors is calculated as the inner ring temperature, and the average value of the temperatures collected by several inner ring edge temperature sensors and several outer ring edge temperature sensors is calculated as the outer ring temperature.

9. The optimization method for improving the temperature uniformity of a hot plate according to claim 8, characterized in that: When the temperature of the inner ring reaches the threshold of initial fast heating, heating is stopped. When the temperature of the outer ring also reaches the threshold of initial fast heating, the inner and outer ring heating wires are synchronously and slowly heated according to different initial powers.

10. The optimization method for improving the temperature uniformity of a hot plate according to claim 8 or 9, characterized in that: The S5 collects the changes in the inner ring temperature and the outer ring temperature per unit time as the inner ring temperature rise and the outer ring temperature rise respectively. If the inner ring temperature rise is different from the outer ring temperature rise and does not exceed the rated power, the heating wire with lower temperature rise increases the power; if the inner ring temperature rise is different from the outer ring temperature rise and exceeds the rated power, the heating wire with higher temperature rise reduces the power; the feedback is cyclically performed until the inner ring temperature rise is the same as the outer ring temperature rise, and the initial power is updated according to the power at this time.

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