Vacuum pressing method and device for heat-conducting glue of electrostatic chuck

Abstract

The invention relates to an electrostatic chuck heat-conducting glue vacuum pressing method which comprises the following steps: S1, placing an edge ring of which the lower surface is coated with heat-conducting glue in an edge area of an electrostatic chuck to form a to-be-pressed assembly body; wherein a temperature sensor is arranged on the upper surface of the edge area of the electrostatic chuck, and the initial state of the upper surface of the temperature sensor is higher than that of the upper surface of the electrostatic chuck; s2, a vacuum environment is established, and a cavity for containing the to-be-pressed assembly is vacuumized; s3, applying pressure to the edge ring through a pressure applying mechanism while maintaining the vacuum environment of the cavity, enabling the edge ring to be continuously attached to the electrostatic chuck for a first preset time so as to discharge residual gas in the heat-conducting glue to complete press fit, and enabling the upper surface of the temperature sensor to be flush with the upper surface of the electrostatic chuck through press fit. The method provided by the invention can effectively discharge residual gas in the heat-conducting glue, ensures that the viscosity of the heat-conducting glue is good, and has obvious advantages.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing technology, specifically relating to a vacuum pressing method and apparatus for electrostatic chuck thermal conductive adhesive. Background Technology

[0002] In the field of semiconductor manufacturing technology, the stable operation of semiconductor process equipment is crucial to ensuring chip production yield and efficiency. Among these processes, the edge ring on the electrostatic chuck requires precise temperature control. To ensure effective heat transfer between the edge ring and the heater, current standard operating procedures (SOPs) stipulate the use of manufacturer-specified thermal conductive adhesive. However, this manufacturer-specified thermal conductive adhesive has significant drawbacks, including high procurement costs and excessively long delivery cycles, placing enormous pressure on the operating costs and production continuity of chip manufacturing companies.

[0003] To reduce costs, the industry often considers using aftermarket thermal conductive adhesives with similar parameters as substitutes. However, practice shows that although the material parameters of aftermarket thermal conductive adhesives are similar to those of original equipment manufacturer (OEM) products at room temperature, key technical defects emerge in practical applications. Specifically, the existing process involves applying the thermal conductive adhesive in an atmospheric environment according to OEM standards. When this method is used with aftermarket products, during the vacuuming process in the equipment chamber, residual gas within the adhesive escapes due to pressure changes, causing pores to form inside the cured thermal conductive adhesive, reducing its adhesion. This directly leads to poor contact or failure to pressurize the temperature sensor on the edge ring, ultimately triggering an abnormal temperature alarm in the equipment, resulting in maintenance failure and the inability to start the equipment normally.

[0004] Therefore, it is essential to design a vacuum pressing method and apparatus for electrostatic chuck thermal conductive adhesive in semiconductor process equipment.

[0005] It is understood that the above statements only provide background information related to the present invention and do not necessarily constitute prior art. Summary of the Invention

[0006] The purpose of this invention is to provide a vacuum pressing method and apparatus for electrostatic chuck thermal conductive adhesive, which is used to remove residual gas in the thermal conductive adhesive and ensure good adhesion of the thermal conductive adhesive to complete subsequent processes.

[0007] To achieve the above objectives, the present invention provides a vacuum pressing method for thermally conductive adhesive on an electrostatic chuck, comprising the following steps: S1, placing an edge ring with thermally conductive adhesive coated on its lower surface on the edge region of an electrostatic chuck to form an assembly to be pressed; wherein, a temperature sensor is provided on the upper surface of the edge region of the electrostatic chuck, and the initial state of the upper surface of the temperature sensor is higher than the upper surface of the electrostatic chuck; S2, establishing a vacuum environment by evacuating the chamber containing the assembly to be pressed; S3, while maintaining the vacuum environment in the chamber, applying pressure to the edge ring through a pressure application mechanism to keep it in close contact with the electrostatic chuck for a first preset time to expel residual gas in the thermally conductive adhesive and complete the pressing, and making the upper surface of the temperature sensor flush with the upper surface of the electrostatic chuck through pressing.

[0008] Preferably, the edge region of the electrostatic chuck is provided with a plurality of temperature probe slots distributed at equal intervals, and the temperature sensors are respectively installed in the temperature probe slots; wherein, before the pressing in step S3, the upper surface of the temperature sensor is higher than the slot opening plane of the temperature probe slot; after the pressing in step S3, the upper surface of the temperature sensor is flush with the slot opening plane of the temperature probe slot.

[0009] Preferably, in step S2, the pressure of the vacuum environment is less than or equal to 200 mTorr.

[0010] Preferably, the pressure application mechanism is disposed in the cavity; and the pressing surface of the pressure application mechanism matches the annular structure of the edge ring, so that the applied pressure is evenly distributed throughout the entire annular area of ​​the edge ring.

[0011] Preferably, the contact position between the pressing surface and the edge ring is in the middle region of the ring width of the edge ring.

[0012] Preferably, the pressure applied by the pressure application mechanism is 90 N to 110 N.

[0013] Preferably, the first preset time is 25 min to 35 min.

[0014] Preferably, before step S1, the method further includes a step of uniformly applying thermally conductive adhesive to a coating mold and uniformly bonding the thermally conductive adhesive to the lower surface of the edge ring through the coating mold.

[0015] Preferably, the adhesive coating mold has an annular structure that matches the edge ring.

[0016] Preferably, after step S3, a step of quality inspection of the electrostatic chuck with the thermally conductive adhesive pressed together is further included. This step specifically includes: heating the electrostatic chuck to raise its temperature from a first temperature to a second temperature; detecting the temperature change of the edge ring using the temperature sensor; and determining the pressing quality of the thermally conductive adhesive based on the time required for the edge ring to rise from the first temperature to the second temperature. If the time required for the edge ring to rise from the first temperature to the second temperature is within a second preset time range, then the pressing quality of the thermally conductive adhesive is determined to be qualified.

[0017] Preferably, the first temperature is 15 °C to 25 °C, the second temperature is 50 °C to 70 °C, and the second preset time range is 8 s to 16 s.

[0018] The present invention also provides a vacuum pressing device for implementing the vacuum pressing method, comprising: a chamber for accommodating the assembly to be pressed; a vacuum system connected to the chamber for evacuating the interior of the chamber; a pressure applying mechanism disposed in the chamber for applying pressure to the edge ring in a vacuum environment; and a control system electrically connected to the vacuum system and the pressure applying mechanism for controlling the vacuuming process and the magnitude and duration of the applied pressure.

[0019] Preferably, the vacuum pressing device further includes: a heating mechanism disposed in the cavity or integrated with the electrostatic chuck for heating the electrostatic chuck; an external temperature detection terminal communicatively connected to the temperature sensor for acquiring temperature data of the edge ring; wherein, the control system is also electrically connected to the heating mechanism and the external temperature detection terminal for controlling the heating process of the heating mechanism and judging the pressing quality of the thermally conductive adhesive based on the temperature data.

[0020] In summary, compared with the prior art, the vacuum pressing method for electrostatic chuck thermal conductive adhesive in semiconductor process equipment provided by the present invention has at least the following beneficial effects: (1) The pressing method of the present invention changes the pressing operation of thermal conductive adhesive from "atmospheric environment" to "vacuum environment". It uses vacuum pressure difference as driving force to actively and effectively extract the residual gas inside the thermal conductive adhesive, ensuring that the adhesive is dense and pore-free; thereby effectively eliminating equipment alarms caused by abnormal edge ring temperature, and improving the stability of equipment operation and production efficiency. (2) The pressing method of the present invention is designed for vacuum pressing process. Through a large number of experiments, the key and optimized process parameters have been determined, forming a complete, repeatable and stable technical solution. (3) The pressing method of the present invention can get rid of the dependence of existing processes on original parts, shorten the procurement delivery time from 3 months to 1 day, and greatly improve the flexibility of equipment maintenance and supply chain security; (4) The bonding method of the present invention enables semiconductor equipment factories to use low-cost aftermarket components safely and stably, saving a lot of costs. Attached Figure Description

[0021] Figure 1 This is a flowchart of the vacuum pressing method of the present invention; Figure 2 This is a schematic diagram of the vacuum pressing device for the vacuum pressing method of the present invention; In the picture: 1-Electrostatic chuck, 2-Edge ring, 3-Thermal conductive adhesive, 4-Pressure application mechanism, 5-Temperature sensor, 6-Cavity, 7-Vacuum system, 8-Heating mechanism. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and by providing a detailed description of a preferred embodiment.

[0023] It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the purpose of the embodiments of the present invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of the present invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only used to complement the content disclosed in the specification, for those skilled in the art to understand and read, and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by the present invention, should still fall within the scope of the technical content disclosed in the present invention.

[0024] It should be noted that, in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only the expressly listed elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0025] like Figure 1 and Figure 2 As shown, this invention provides a vacuum pressing method for electrostatic chuck thermal conductive adhesive, specifically including the following steps: S1. Place the edge ring 2 with thermally conductive adhesive 3 on its lower surface into the edge area of ​​the electrostatic chuck 1 to form the assembly to be pressed together. A temperature sensor 5 is provided on the upper surface of the edge region of the electrostatic chuck 1, and the initial state of the upper surface of the temperature sensor 5 is higher than that of the upper surface of the electrostatic chuck 1. S2. Establish a vacuum environment by evacuating the chamber 6 containing the assembly to be assembled. S3. While maintaining the vacuum environment of the chamber 6, pressure is applied to the edge ring 2 by the pressure application mechanism 4 to keep it in close contact with the electrostatic chuck 1 for a first preset time, so as to expel the gas remaining in the thermally conductive adhesive 2 and complete the pressing. The pressing makes the upper surface of the temperature sensor 5 flush with the upper surface of the electrostatic chuck 1.

[0026] Furthermore, the edge region of the electrostatic chuck 1 is provided with multiple temperature probe slots distributed at equal intervals, and the temperature sensors 5 are respectively installed in the temperature probe slots; wherein, before the pressing in step S3, the upper surface of the temperature sensor 5 is higher than the slot opening plane of the temperature probe slot; after the pressing in step S3, the upper surface of the temperature sensor 5 is flush with the slot opening plane of the temperature probe slot. This allows the temperature sensor 5 to be accurately embedded in the edge region of the electrostatic chuck 1 without affecting the pressing of its edge ring 2 due to protrusion.

[0027] Furthermore, in step S2, the pressure of the vacuum environment is less than or equal to 200 mTorr. Under this vacuum condition, air within chamber 6 and any micro-bubbles that may exist in the thermally conductive adhesive 3 can be effectively eliminated, ensuring sufficient contact between the thermally conductive adhesive 3 and the electrostatic chuck 1 and edge ring 2 during the pressing process. This avoids affecting thermal conductivity and pressing quality due to the presence of bubbles, providing a reliable guarantee for subsequent accurate temperature measurement and stable equipment operation. Simultaneously, this vacuum range also meets the equipment design requirements and relevant process standards, ensuring the pressing effect without causing excessive load or damage to the equipment.

[0028] Furthermore, the pressure application mechanism 4 is disposed within the chamber 6; and the pressing surface of the pressure application mechanism 4 matches the annular structure of the edge ring 2, so that the applied pressure is evenly distributed throughout the entire annular area of ​​the edge ring 2.

[0029] Specifically, the contact position between the pressing surface and the edge ring is in the middle region of the ring width of the edge ring.

[0030] Understandably, this design ensures that pressure can be transmitted evenly and stably to every part of the edge ring 2 during the pressing process; and this uniform pressure distribution helps to avoid excessive or insufficient local pressure, thereby preventing deformation or damage to the edge ring 2 due to uneven pressure, and further ensuring the quality and effect of pressing.

[0031] Furthermore, the pressure applied by the pressure application mechanism 4 is 90 N to 110 N.

[0032] Furthermore, the first preset time is 25 min to 35 min.

[0033] Furthermore, before step S1, the process includes a step of uniformly coating the thermally conductive adhesive 3 onto the coating mold and then uniformly bonding the thermally conductive adhesive 3 to the lower surface of the edge ring 2 using the coating mold.

[0034] Furthermore, the adhesive coating mold has an annular structure that matches the edge ring 2.

[0035] Furthermore, to ensure that the electrostatic chuck 1 with the thermally conductive adhesive 3 properly bonded can be used in actual processes, after step S3, a quality inspection step is also included for the electrostatic chuck 1 with the thermally conductive adhesive 3 properly bonded. This step specifically includes: The electrostatic chuck 1 is heated so that its temperature rises from a first temperature to a second temperature. The temperature change of the edge ring 2 is detected by the temperature sensor 5; The bonding quality of the thermally conductive adhesive 3 is determined based on the time required for the edge ring 2 to rise from the first temperature to the second temperature; If the time required for the edge ring 2 to rise from the first temperature to the second temperature is within the second preset time range, then the thermally conductive adhesive 3 is judged to be of qualified pressing quality.

[0036] Specifically, in a preferred embodiment of the present invention, the first temperature is 15°C to 25°C, the second temperature is 50°C to 70°C, and the second preset time range is 8s to 16s.

[0037] Furthermore, such as Figure 2 As shown, the present invention also provides a vacuum pressing apparatus for implementing the above-described vacuum pressing method, comprising: Chamber 6 is used to accommodate the assembly to be pressed together; Vacuum system 7, connected to chamber 6, is used to evacuate the interior of chamber 6; A pressure application mechanism 4 is disposed in the chamber 6 and is used to apply pressure to the edge ring 2 in a vacuum environment; The control system (not shown in the figure) is electrically connected to the vacuum system 7 and the pressure application mechanism 4, and is used to control the vacuuming process and the magnitude and duration of pressure application.

[0038] It should be noted that the control system can adjust the contact pressure between the pressing surface of the pressure applying mechanism 4 and the edge ring 2 by controlling the rising and falling movements of the pressure applying mechanism 4, thereby ensuring that the pressure applied by the pressure applying mechanism 4 to the edge ring 2 meets the preset requirements and ensuring the stable operation and working efficiency of the entire system.

[0039] Furthermore, the vacuum pressing device also includes: Heating mechanism 8, disposed in the chamber 2 or integrated with the electrostatic chuck 1, is used to heat the electrostatic chuck 1; An external temperature detection terminal (not shown in the figure) is communicatively connected to the temperature sensor 5 and is used to acquire the temperature data of the edge ring 2; The control system is also electrically connected to the heating mechanism 8 and the external temperature detection terminal, and is used to control the heating process of the heating mechanism 8 and to determine the pressing quality of the thermally conductive adhesive 3 based on the temperature data.

[0040] Specifically, in actual operation, it is worth noting that once the electrostatic chuck 1 begins heating, the temperature sensor 5 will capture the temperature data of the edge ring 2 in real time and accurately. As the heating process continues, the temperature of the edge ring 2 gradually rises, and the temperature sensor 5 continuously feeds back the temperature information to the control system. The control system, based on existing programs, accurately calculates the time it takes for the edge ring 2 to rise from the first temperature to the second temperature. If this time falls within the second preset time range of 8 to 16 seconds, the control system will determine that the thermally conductive adhesive 3 is of acceptable quality, and the process can proceed to subsequent production or use. Conversely, if the time is outside this range, it indicates a problem with the thermally conductive adhesive 3's bonding quality, preventing it from entering subsequent production or use, and requiring re-bonding.

[0041] In summary, the vacuum pressing method for electrostatic chuck thermal conductive adhesive in semiconductor process equipment provided by this invention changes the pressing operation of the thermal conductive adhesive from an "atmospheric environment" to a "vacuum environment," using vacuum pressure difference as the driving force to actively and effectively extract residual gas inside the thermal conductive adhesive, ensuring that the adhesive is dense and free of pores. This effectively eliminates equipment alarms caused by abnormal edge ring temperature, improving the stability of equipment operation and production efficiency. Furthermore, the pressing method of this invention can eliminate the dependence of existing processes on original parts, shortening the procurement lead time from 3 months to 1 day, greatly improving the flexibility of equipment maintenance and supply chain security, while also saving significant costs.

[0042] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A vacuum press-bonding method of electrostatic chucking heat conductive adhesive, characterized by, The method comprises the following steps: S1, placing an edge ring with a lower surface coated with a heat-conductive adhesive on the edge area of an electrostatic chuck to form a to-be-bonded assembly; wherein the upper surface of the edge area of the electrostatic chuck is provided with a temperature sensor, and the initial state of the upper surface of the temperature sensor is higher than the upper surface of the electrostatic chuck; S2, establishing a vacuum environment, and vacuumizing the chamber containing the to-be-bonded assembly; S3, while maintaining the vacuum environment of the chamber, applying pressure to the edge ring by a pressure applying mechanism to make it continuously adhere to the electrostatic chuck, and continuously maintaining for a first preset time to exhaust the residual gas in the heat-conductive adhesive to complete the bonding, and to make the upper surface of the temperature sensor flush with the upper surface of the electrostatic chuck through the bonding.

2. The vacuum press bonding method according to claim 1, wherein, The edge area of the electrostatic chuck is provided with a plurality of temperature probe grooves distributed at equal intervals, and the temperature sensor is respectively installed in the temperature probe groove; Wherein, before the bonding in step S3, the upper surface of the temperature sensor is higher than the groove plane of the temperature probe groove; after the bonding in step S3, the upper surface of the temperature sensor is flush with the groove plane of the temperature probe groove.

3. The vacuum press bonding method according to claim 1, wherein In step S2, the pressure of the vacuum environment is less than or equal to 200 mTorr.

4. The vacuum press bonding method according to claim 1, wherein The pressure applying mechanism is arranged in the chamber; And the bonding surface of the pressure applying mechanism matches the annular structure of the edge ring, so that the applied pressure is uniformly distributed in the whole annular area of the edge ring.

5. The vacuum press bonding method according to claim 4, wherein The contact position of the bonding surface and the edge ring is the middle area of the width of the annular body of the edge ring.

6. The vacuum press bonding method according to claim 1, wherein The pressure applied by the pressure applying mechanism is 90 N to 110 N.

7. The vacuum press bonding method according to claim 1, wherein The first preset time is 25 min to 35 min.

8. The vacuum press bonding method according to claim 1, wherein Before step S1, it also includes the steps of uniformly coating the heat-conductive adhesive on the adhesive coating mold, and uniformly bonding the heat-conductive adhesive on the lower surface of the edge ring through the adhesive coating mold.

9. The vacuum press bonding method according to claim 8, wherein The adhesive coating mold has an annular structure matching the edge ring.

10. The vacuum press bonding method according to claim 1, wherein After step S3, it also includes the step of quality detection of the electrostatic chuck with bonded heat-conductive adhesive, which specifically comprises: heating the electrostatic chuck to raise the temperature of the electrostatic chuck from a first temperature to a second temperature; detecting the temperature change of the edge ring by the temperature sensor; judging the bonding quality of the heat-conductive adhesive according to the time required for the edge ring to raise from the first temperature to the second temperature; Wherein, if the time required for the edge ring to raise from the first temperature to the second temperature is within a second preset time range, it is judged that the bonding quality of the heat-conductive adhesive is qualified.

11. The vacuum press bonding method according to claim 10, wherein The first temperature is 15°C to 25°C, the second temperature is 50°C to 70°C, and the second preset time range is 8s to 16s.

12. A vacuum press device for implementing the vacuum press method according to any one of claims 1 to 11, characterized by, It comprises: a chamber for containing the to-be-bonded assembly; a vacuum system connected with the chamber for vacuumizing the inside of the chamber; a pressure applying mechanism arranged in the chamber for applying pressure to the edge ring in a vacuum environment; A control system electrically connected with the vacuum system and the pressure applying mechanism, for controlling the vacuumizing process and the size and time of the pressure application.

13. The vacuum press apparatus of claim 12, wherein, Further comprising: A heating mechanism arranged in the chamber or integrated with the electrostatic chuck, for heating the electrostatic chuck; An external temperature detection terminal in communication connection with the temperature sensor, for acquiring temperature data of the edge ring; Wherein, the control system is further electrically connected with the heating mechanism and the external temperature detection terminal, for controlling the heating process of the heating mechanism, and judging the pressing quality of the heat-conducting glue based on the temperature data.

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