Electric hot plate testing method based on different air pressure states

Abstract

The invention discloses an electric hot plate testing method based on different air pressure states, which comprehensively detects the appearance quality, the electrical performance, the heating performance and the vacuum performance of an electric hot plate through the setting of a normal pressure testing environment and a negative pressure testing environment, and ensures the stability and the reliability of the electric hot plate in different use environments. Specifically, the appearance detection, the electrical performance detection, the vacuum performance detection and the heating performance detection of the electric hot plate are respectively carried out in a normal pressure state and a negative pressure state.

Description

Technical Field

[0001] The invention relates to the technical field of electric heating plate performance testing, and in particular to an electric heating plate testing method based on different gas pressure states. Background Art

[0002] Many electric heating plates need to work under vacuum negative pressure. For example, in semiconductor thin film deposition equipment, the electric heating plate heats the wafer placed on it to the appropriate process temperature under pinhole negative pressure to achieve process purposes such as thin film deposition, etching and cleaning. Since the performance indicators of the electric heating plate under vacuum negative pressure are not completely consistent with those under atmospheric pressure, it is necessary to evaluate not only the performance of the electric heating plate under atmospheric pressure, but also the performance of the electric heating plate under vacuum negative pressure.

[0003] The patent "Electric heating plate evaluation method, CN201310711953" provides an evaluation method for electric heating plates under atmospheric pressure, but there is no relevant patent for the evaluation method for electric heating plates under vacuum negative pressure. This patent provides an evaluation method applicable to various electric heating plates under vacuum negative pressure, thus forming a systematic evaluation method for electric heating plates under both atmospheric pressure and vacuum negative pressure.

[0004] Many semiconductor devices need to work under a certain vacuum negative pressure state, and need a heating plate to heat the wafer to achieve the manufacturing conditions of the semiconductor process. Depending on the working temperature, the heating plate is made of aluminum, copper, stainless steel, ceramic, etc. In semiconductor equipment, the heating plate as a whole is generally placed in the vacuum chamber of the equipment to heat the wafer, but the heating power supply and temperature measuring thermocouple of the heating plate must pass through the vacuum chamber to connect with the external power supply and temperature measuring thermocouple. This causes two problems. First, because there may be sand holes, pinholes and cracks on the heating plate, air leakage will occur through the electrodes of the heating plate and the temperature measuring thermocouple tubes and other places connected to the external atmospheric environment of the equipment, thereby destroying the vacuum degree of the semiconductor equipment and affecting the process quality; second, because the heat load on the surface of the heating plate under vacuum is different from that under atmosphere, the heating-maintaining-cooling characteristics of the heating plate are affected. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for testing a heating plate under different air pressures, aiming to accurately evaluate the working performance and stability of the heating plate by simulating different air pressure environments.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a method for testing a hot plate under different air pressure states. First, perform the following steps on the hot plate to test the normal pressure: A1. Appearance inspection: Inspection of the appearance quality of the heating plate; A2. Electrical performance test: Place the heating plate in an oven and dry it at the first rated drying temperature for the first rated time and let it cool, then test the electrical properties of the heating plate; A3. Heating performance test: within the rated power range, the heating power is changed multiple times to test the thermal response characteristics of the heating plate under normal pressure; Secondly, after completing the normal pressure test, perform the negative pressure test on the following steps of the heating plate: B1. Pretreatment: placing the hot plate in an oven and drying it at a second rated drying temperature for a second rated time to remove the gas adsorbed on the surface; B2. Vacuum performance test: The electric heating plate is sealed and installed on the preset vacuum chamber, and the vacuum pump led out from the vacuum chamber is used to evacuate the chamber, so as to detect and obtain various vacuum performances during the evacuation period; B3. Heating performance test under negative pressure state: After the vacuum chamber reaches the predetermined vacuum negative pressure state and stabilizes, within the rated power range, the heating power is changed multiple times to successively test the thermal response characteristics of the heating plate under negative pressure state.

[0007] Furthermore, in step A1, the appearance quality inspection includes: shape and size, surface roughness, number and position of sand holes, cracks and pinholes of the electric heating plate.

[0008] Further, in step A1, the electrical properties include: insulation resistance, heating resistance, and grounding resistance of the electric heating plate.

[0009] Furthermore, in step A1, the vacuum performance includes the pumping speed, pumping time, and vacuum degree of the vacuum chamber.

[0010] Furthermore, in step A3 or B3, before the formal heating performance test is performed, the electric heating plate needs to be subjected to at least one "heating-maintaining-cooling" process in advance.

[0011] Further, in steps A3 and / or B3, the electric heating plate is powered on and the temperature is increased based on the normal temperature state, and the temperature value is recorded in real time once every rated time interval as the indicated temperature value until the electric heating plate reaches the preset maximum temperature value and stops heating. Finally, a "heating power-indicated temperature value" relationship curve is drawn based on the recorded temperature values.

[0012] Further, in step A3 and / or B3, the electric heating plate is provided with three triangular ring-shaped perforations adjacent to the side edge positions, two of which are provided for the preset heating electrodes to be provided, and the third perforation is provided for the preset temperature detection unit to be provided, wherein the temperature value detected by the temperature detection unit is used as the indicated temperature value recorded in real time. The present invention adopts the above scheme, and its beneficial effects are: the present invention can comprehensively and accurately evaluate the performance and stability of the electric heating plate under different working conditions by simulating different air pressure environments to test the electric heating plate. Specifically, the beneficial effects are as follows: Improve the accuracy of the assessment: Testing the heating plate under normal pressure and negative pressure can more comprehensively reflect the actual working performance of the heating plate under different air pressure conditions, thereby improving the accuracy of the assessment.

[0013] Enhance product reliability: By simulating tests under extreme conditions (such as negative pressure), potential problems with the heating plate, such as poor sealing and unstable vacuum performance, can be discovered early, and improvements can be made during product design or production to enhance the overall reliability of the product.

[0014] Optimize performance parameters: By changing the heating power multiple times to detect the thermal response characteristics of the heating plate and drawing a "heating power-indicated temperature value" relationship curve, data support can be provided for the performance optimization of the heating plate, helping manufacturers to adjust design parameters so that the heating plate can maintain excellent performance under different gas pressures. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the normal pressure detection process of the embodiment.

[0016] Figure 2 Schematic diagram of negative pressure detection process of an embodiment.

[0017] Figure 3 Schematic diagram of a vacuum testing device according to an embodiment.

[0018] Figure 4 Schematic diagram of the electric heating plate of the embodiment. DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of the present invention, the present invention is described more fully below with reference to the accompanying drawings. The accompanying drawings provide preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. The purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly and comprehensively understood.

[0020] Many existing semiconductor devices need to work under a certain vacuum negative pressure state, and need an electric heating plate 5 to heat the wafer to achieve the manufacturing conditions of the semiconductor process. Specifically, in the existing semiconductor devices, the electric heating plate 5 as a whole is generally placed in the vacuum chamber of the device to heat the wafer, but the heating power supply and temperature measuring thermocouple of the electric heating plate 5 must pass through the vacuum chamber to connect with the external power supply and temperature measuring thermocouple. This causes two problems. First, because there may be sand holes, pinholes and cracks on the electric heating plate 5, air leakage will occur through the heating electrode and temperature measuring thermocouple tube of the electric heating plate 5 and the connection with the external atmospheric environment of the equipment, thereby destroying the vacuum degree of the semiconductor equipment and affecting the process quality; second, because the heat load on the surface of the electric heating plate 5 under vacuum is different from that under the atmosphere, the heating-maintaining-cooling characteristics of the electric heating plate 5 are affected.

[0021] Based on this, see Appendix Figure 1-3 As shown, this embodiment discloses a method for testing a hot plate under different air pressure states, which improves the disadvantages of traditional detection methods in a targeted manner and proposes a more rigorous and reasonable detection method, especially by increasing the performance of the simulated hot plate 5 under vacuum conditions, thereby more intuitively and clearly showing the product performance of the hot plate 5 to be tested, so as to better meet the use requirements of semiconductor process equipment.

[0022] Specifically, the testing method of this embodiment includes two parts: firstly, performing a normal pressure test on the electric heating plate 5 , and then performing a negative pressure test on the electric heating plate 5 .

[0023] In this embodiment, the normal pressure detection of the electric heating plate 5 includes the following steps: Step A1. Appearance inspection: inspect the appearance quality of the electric heating plate 5 , wherein in step A1 , the appearance quality inspection includes: shape and size, surface roughness, number and position of sand holes, cracks, and pinholes of the electric heating plate 5 .

[0024] Specifically, the shape, size and surface roughness of the electric heating plate 5 are measured by using high-precision measuring tools (such as vernier calipers, surface roughness meters, etc.), and the surface of the electric heating plate 5 is visually inspected for defects such as sand holes, cracks, pinholes, etc. If so, their number and positions are recorded. If it does not meet the predetermined quality requirements, the subsequent inspection of the electric heating plate 5 is terminated and it is treated as a waste part.

[0025] Step A2. Electrical performance test: After placing the electric heating plate 5 in an oven and drying it at the first rated drying temperature for the first rated time and cooling it, test the electrical properties of the electric heating plate 5. In this embodiment, the first rated drying temperature is 250°C, the first rated time is 3 hours, and the electrical properties include: insulation resistance, heating resistance, and grounding resistance of the electric heating plate 5. Specifically, use an insulation resistance tester, a multimeter, and other equipment to test the insulation resistance, heating resistance, and grounding resistance of the electric heating plate 5, respectively, to ensure that the electrical performance indicators meet the design requirements.

[0026] Step A3. Heating performance test: Within the rated power range, the heating power is changed multiple times to detect the thermal response characteristics of the electric heating plate 5 under normal pressure. Before the formal heating performance test, the electric heating plate 5 needs to be pre-processed with at least one "heating-maintaining-cooling" process to stabilize its working state, so that abnormalities such as heating abnormalities can be discovered in time, which is more conducive to subsequent heating performance testing. Secondly, within the rated power range, the electric heating plate 5 is heated in sequence at different power levels (such as 25%, 50%, 75%, and 100% rated power), and the temperature value of the electric heating plate 5 is recorded once every certain time interval (such as 5 minutes) until the preset maximum temperature value (such as 350°C) is reached. In addition, the recorded data is used to draw a "heating power-indicated temperature value" relationship curve diagram, so as to intuitively show the relationship curve between the heating power and the indicated temperature value under normal pressure.

[0027] Based on the above steps A1-A3, the normal pressure detection of the electric heating plate 5 is completed. The user can refer to the "heating power-indicated temperature value" relationship curve to intuitively understand the parameter performance of the current electric heating plate 5 under normal pressure.

[0028] In this embodiment, the negative pressure detection of the electric heating plate 5 includes the following steps: Step B1: Pretreatment: Place the electric heating plate 5 in an oven and dry it at a second rated drying temperature for a second rated time to remove the gas adsorbed on the surface, wherein the second rated drying temperature of this embodiment is 250°C, and the first rated time is 3-5 hours. The electric heating plate 5 is dried by pretreatment to eliminate the gas on the surface, thereby facilitating the subsequent negative pressure suction operation.

[0029] Step B2: Vacuum performance test: The electric heating plate 5 is sealed and installed on a preset vacuum chamber, and a vacuum pump from the vacuum chamber is used to perform a vacuum process, so as to test and obtain various vacuum performances during the vacuum process.

[0030] For ease of understanding, the above-mentioned normal pressure detection and negative pressure detection are explained below in conjunction with a specific vacuum testing device. Figure 3The vacuum test device shown includes a test platform 2, a fixture 4 fixed on the test platform and used to support the electric heating plate 5, and a vacuum chamber 1, wherein the electric heating plate 5 is fixed on the top surface of the fixture by a number of support columns (there is a certain distance between the two, and the size of the distance directly solves the thermal resistance of the test platform, and it is necessary to ensure that the temperature of the test platform and the fixture does not exceed 50°C), and the vacuum chamber 1 can be relatively buckled on the top surface of the electric heating plate 5 during the negative pressure detection stage, so that the electric heating plate 5 corresponds to the sealing cover of the lower opening of the vacuum chamber 1 (using an O-ring for sealing), and the vacuum chamber is connected to the vacuum pump 8, vacuum gauge 7 and other components. Secondly, the vacuum gauge 7 adopts a diaphragm resistor composite vacuum gauge, and its measurement accuracy is 1.0×10-1~3.0×10+3 Pa: ±5%, resolution 1%, and response time <100ms. Specifically, the method of using the above-mentioned vacuum testing device is as follows: first, install the electric heating plate 5 into the fixing fixture of the vacuum platform and cover the vacuum chamber; then use a helium gas detector to evacuate and detect leaks to confirm that there is no leakage in the vacuum chamber 1 after installation; then, use a vacuum pump to evacuate the vacuum degree in the chamber to the ultimate vacuum, and the vacuum degree must be less than 0.01Torr. This vacuum degree is the vacuum range used when simulating the electric heating plate 5 in related equipment.

[0031] Step B3. Heating performance test under negative pressure state: After the vacuum chamber reaches the predetermined vacuum negative pressure state and stabilizes, within the rated power range, the heating power is changed multiple times to detect the thermal response characteristics of the electric heating plate 5 under the negative pressure state. Before the formal heating performance test, the electric heating plate 5 needs to be pre-processed with at least one "heating-maintaining-cooling" process to stabilize its working state, so that abnormalities such as heating abnormalities can be discovered in time, which is more conducive to subsequent heating performance testing. Secondly, within the rated power range, the electric heating plate 5 is heated in sequence at different power levels (such as 25%, 50%, 75%, and 100% rated power), and the temperature value of the electric heating plate 5 is recorded once every certain time interval (such as 5 minutes) until the preset maximum temperature value (such as 350°C) is reached. In addition, the recorded data is used to draw a "heating power-indicating temperature value" relationship curve diagram, so as to intuitively show the relationship curve between the heating power and the indicating temperature value under the negative pressure state.

[0032] Based on the above steps B1-B3, the negative pressure detection of the electric heating plate 5 is completed. The user can refer to the "heating power-indicated temperature value" relationship curve to intuitively understand the parameter performance of the current electric heating plate 5 under the negative pressure state.

[0033] In addition, by using the above-mentioned vacuum testing device as a fixed carrier for the electric heating plate 5, and matching it with the corresponding heating electrode 3 and the temperature detection unit 6, the temperature collection of steps A3 and B3 can be realized. Specifically, the electric heating plate 5 is provided with three perforations in a triangular ring shape and adjacent to the side edge position. The electric heating plate 5 is provided with three perforations in a triangular ring shape and adjacent to the side edge position, two of which are for the preset heating electrodes 3 to penetrate and cooperate, and the third perforation position is for the preset temperature detection unit 6 to penetrate and cooperate. Therefore, after the electric heating plate 5 is fixed on the top surface of the fixed fixture, the preset two heating electrodes 3 pass through the two perforations of the electric heating plate 5 one by one, and the temperature detection unit 6 can be correspondingly penetrated in the third perforation position. Preferably, the temperature detection unit 6 of this embodiment adopts a tubular thermocouple as a detection element, and then the external power line is connected to the end of each power motor accordingly, so as to realize the functions of power-on heating and temperature detection.

[0034] Further, in steps A3 and / or B3, the temperature value detected by the temperature detection unit is used as the indicated temperature value recorded in real time. In this way, the test result at the location of the temperature detection unit 6 can be used to intuitively express the heating temperature of the electric heating plate 5, thereby being closer to the actual working condition of the electric heating plate 5, and being more convenient to intuitively and accurately express the parameter performance of the electric heating plate 5, and being more convenient to calculate the stability and uniformity of the electric heating plate 5.

[0035] In this embodiment, the indicated temperature values ​​obtained under normal pressure and negative pressure can be used to calculate the temperature fluctuation and standard deviation of the electric heating plate 5, specifically: Average temperature:

[0036] Where Ti is the temperature value obtained from the ith measurement and n is the number of measurements. Temperature fluctuation range:

[0037] where max(Ti)max(Ti) and min(Ti)min(Ti) are the maximum and minimum values ​​of the measured temperatures, respectively.

[0038] Temperature standard deviation:

[0039] By performing calculations under normal pressure and negative pressure respectively, a more accurate performance evaluation of the electric heating plate 5 can be obtained to determine the temperature stability and uniformity.

[0040] Through the above specific embodiments, the present invention provides a comprehensive and systematic testing method for the electric heating plate 5, which not only covers the appearance quality, electrical properties and heating performance tests under normal pressure, but also innovatively introduces the vacuum performance and heating performance tests under negative pressure environment, providing strong technical support for the research and development, production and quality control of the electric heating plate 5.

[0041] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any technician familiar with the art who, without departing from the scope of the technical solution of the present invention, makes more possible changes and modifications to the technical solution of the present invention using the technical content disclosed above, or modifications are all equivalent embodiments of the present invention. Therefore, any equivalent and equivalent changes made according to the ideas of the present invention without departing from the content of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for testing a hot plate under different air pressure conditions, characterized in that: First, the electric heating plate (5) is subjected to normal pressure testing in the following steps: A1. Appearance inspection: Inspection of the appearance quality of the heating plate (5); A2. Electrical performance test: Place the electric heating plate (5) in an oven and dry it at a first rated drying temperature for a first rated time and let it cool, then test the electrical properties of the electric heating plate (5); A3. Heating performance test: Within the rated power range, the heating power is changed multiple times to obtain the thermal response characteristics of the heating plate (5) under normal pressure; Secondly, after completing the normal pressure test, the negative pressure test of the following steps of the electric heating plate (5) is performed: B1. Pretreatment: placing the hot plate (5) in an oven and drying at a second rated drying temperature for a second rated time to remove the gas adsorbed on the surface; B2. Vacuum performance test: The electric heating plate (5) is sealed and covered and installed on a preset vacuum chamber, and a vacuum pump is used to evacuate the chamber, thereby testing and obtaining various vacuum performances during the evacuation period; B3. Heating performance test under negative pressure: After the vacuum chamber reaches a predetermined vacuum negative pressure state and stabilizes, within the rated power range, the heating power is changed multiple times to successively test and obtain the thermal response characteristics of the electric heating plate (5) under the negative pressure state.

2. The method for testing a hot plate under different air pressure conditions according to claim 1, characterized in that: In step A1, the appearance quality inspection includes: the shape and size, surface roughness, number and position of sand holes, cracks and pinholes of the electric heating plate (5).

3. The method for testing a hot plate under different air pressure conditions according to claim 1, characterized in that: In step A1, the electrical properties include: insulation resistance, heating resistance, and grounding resistance of the electric heating plate (5).

4. The method for testing a hot plate under different air pressures according to claim 1, characterized in that: In step A1, the vacuum performance includes the pumping speed, pumping time, and vacuum degree of the vacuum chamber.

5. The method for testing a hot plate under different air pressures according to claim 1, characterized in that: In step A3 or B3, before the formal heating performance test is carried out, the electric heating plate (5) needs to be subjected to at least one "heating-maintaining-cooling" process in advance.

6. The method for testing a hot plate under different air pressures according to claim 1, characterized in that: In steps A3 and / or B3, the electric heating plate (5) is powered on and the temperature is increased based on the normal temperature state, and the temperature value is recorded in real time once every rated time interval as the indicated temperature value until the electric heating plate (5) reaches a preset maximum temperature value and stops increasing the temperature. Finally, a "heating power-indicated temperature value" relationship curve is generated based on the recorded temperature values.

7. The method for testing a hot plate under different air pressures according to claim 6, characterized in that: In steps A3 and / or B3, the electric heating plate (5) is provided with three perforations in a triangular ring shape and adjacently distributed at the side edge positions, wherein two of the perforations are provided for the preset heating electrodes (3) to be inserted and matched, and the third perforation is provided for the preset temperature detection unit (6) to be inserted and matched, wherein the temperature value detected by the temperature detection unit is used as the indicated temperature value recorded in real time.

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