Wafer chuck assembly and wafer chuck assembly temperature control method

Abstract

This invention belongs to the field of semiconductor technology and discloses a wafer chuck assembly and a method for controlling the temperature of the wafer chuck assembly. The wafer chuck assembly includes a wafer base, a heat-absorbing layer, a pad, and a chuck. A first cooling channel is provided inside the wafer base; the heat-absorbing layer is disposed on the upper surface of the wafer base; the pad is disposed on the heat-absorbing layer; the chuck is disposed on the pad and there is a gap between it and the heat-absorbing layer, and the heat of the chuck can be radiated to the heat-absorbing layer. In this invention, the heat of the chuck is mainly transferred to the heat-absorbing layer in the form of thermal radiation, and then the heat-absorbing layer transfers the heat radiated by the chuck to the wafer base. The coolant in the first cooling channel flows continuously, carrying away the heat of the wafer base, ultimately achieving cooling of the chuck and preventing the chuck from cracking due to sudden cooling.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a wafer chuck assembly and a method for controlling the temperature of the wafer chuck assembly. Background Technology

[0002] Electrostatic chucks are core components of semiconductor front-end equipment. They enable high-precision, contactless wafer fixation and temperature control, offering advantages such as no mechanical stress, high cleanliness, and no wafer obstruction, making them widely applicable. In PVD (Physical Vapor Deposition) thick-film sputtering processes, high-power sputtering is required to increase the deposition rate, causing rapid heat buildup and a continuous temperature rise in the wafer. The heat radiated from the wafer is rapidly conducted to the electrostatic chuck via the back-blown gas between it and the wafer, resulting in passive heating. When the actual temperature of the electrostatic chuck deviates significantly from the set temperature, it triggers an over-temperature alarm, affecting normal production.

[0003] The current industry standard for heat dissipation involves fixing the electrostatic chuck to the wafer substrate using thermally conductive adhesive or welding. Coolant channels are pre-installed inside the wafer substrate. Heat from the electrostatic chuck is conducted to the wafer substrate and then carried away by the coolant within these channels, achieving heat dissipation and cooling. However, this cooling method, due to the rigid, direct contact between the electrostatic chuck and the wafer substrate, is prone to sudden cooling of the chuck. This large temperature difference can easily cause the ceramic chuck to crack and fail. Summary of the Invention

[0004] The purpose of this invention is to provide a wafer chuck assembly and a wafer chuck assembly temperature control method, which can cool the chuck and prevent the chuck from cracking due to sudden cooling.

[0005] To achieve this objective, the present invention adopts the following technical solution: Wafer chuck assembly, including: A wafer substrate, wherein a first cooling channel is provided within the wafer substrate; A heat-absorbing layer is disposed on the upper surface of the wafer substrate; A pad is disposed on the heat-absorbing layer; A chuck is disposed on the pad and there is a gap between it and the heat-absorbing layer, so that the heat of the chuck can be radiated to the heat-absorbing layer.

[0006] As an optional embodiment of the above-mentioned wafer chuck assembly, the wafer chuck assembly further includes an adhesive layer, and the heat-absorbing layer is bonded to the upper surface of the wafer base through the adhesive layer.

[0007] As an optional embodiment of the aforementioned wafer chuck assembly, the upper surface of the heat-absorbing layer is provided with an uneven structure; and / or, The upper surface of the heat-absorbing layer is provided with a second cooling channel.

[0008] As an optional embodiment of the aforementioned wafer chuck assembly, the heat-absorbing layer is made of at least one of aluminum oxide, chromium oxide, aluminum nitride, zirconium oxide, silicon oxide, and yttrium oxide.

[0009] As an optional embodiment of the above-mentioned wafer chuck assembly, the height of the gap is 0.6mm-1.5mm.

[0010] A method for controlling the temperature of a wafer chuck assembly, comprising the following steps: S1. Real-time acquisition of the actual temperature of the chuck; S2. Based on the actual temperature of the chuck, control the flow rate and supply duration of the coolant entering the first cooling channel until the temperature of the chuck reaches the set temperature.

[0011] As an optional implementation of the above-mentioned wafer chuck assembly temperature control method, step S2 includes: S201. Obtain the difference between the actual temperature and the set temperature of the chuck; S202. Control the flow rate and supply duration of the coolant entering the first cooling channel based on the difference.

[0012] As an optional implementation of the above-mentioned wafer chuck assembly temperature control method, step S202 includes: S2021. Determine whether the difference is less than a first preset difference; If so, proceed to step S2022; If not, proceed to step S2023; S2022. Control the coolant to enter the first cooling channel at a first flow rate, and control the coolant to be continuously supplied for a first duration; S2023. Determine whether the difference is less than a second preset difference; the second preset difference is greater than the first preset difference. If so, the coolant is controlled to enter the first cooling channel at a second flow rate, and the coolant is controlled to be continuously supplied for a second duration; the second flow rate is greater than the first flow rate, and the second duration is greater than the first duration; If not, the coolant is controlled to enter the first cooling channel at a third flow rate, and the coolant is controlled to be continuously supplied for a third duration; the third flow rate is greater than the second flow rate, and the third duration is greater than the second duration.

[0013] As an optional embodiment of the above-mentioned wafer chuck assembly temperature control method, a second cooling channel is provided on the upper surface of the heat-absorbing layer in the wafer chuck assembly. Step S2 further includes: S211. Obtain the temperature rise rate of the chuck based on its actual temperature; S212. Determine whether the temperature rise rate is less than the first value; If so, proceed to step S213; If not, proceed to step S214; S213. Control the coolant to enter the second cooling channel at a fourth flow rate, and supply the coolant to the second cooling channel in an intermittent supply mode. S214. Determine whether the temperature rise rate is less than the second value; the second value is greater than the first value. If so, control the coolant to enter the second cooling channel at a fifth flow rate, and control the supply duration of the coolant entering the second cooling channel to a fourth duration; If not, the coolant is controlled to enter the second cooling channel at a sixth flow rate, and the supply duration of the coolant entering the second cooling channel is controlled to be a fifth duration, wherein the sixth flow rate is greater than the fifth flow rate, and the fifth duration is greater than the fourth duration.

[0014] As an optional embodiment of the above-mentioned wafer chuck assembly temperature control method, at least two temperature measuring points are provided on the chuck. In step S211, the temperature values ​​obtained from all the temperature measurement points are processed to obtain the actual temperature of the chuck.

[0015] As an optional implementation of the above-mentioned wafer chuck assembly temperature control method, when measuring the temperature at the temperature measuring point, if the value measured by the temperature sensor remains unchanged within the effective time, a temperature value is obtained.

[0016] As an optional implementation of the above-mentioned wafer chuck assembly temperature control method, in step S2, when the temperature of the chuck is initially detected to have reached the set temperature, the temperature of the chuck is continuously detected. If the temperature change range of the chuck is less than the set range within a set time period, it is determined that the temperature of the chuck has reached the set temperature.

[0017] The beneficial effects of this invention are: When the wafer chuck assembly proposed in this invention is in operation, the heat of the chuck is mainly transferred to the heat absorption layer in the form of thermal radiation, and then the heat absorption layer transfers the heat radiated by the chuck to the wafer base. The coolant in the first cooling channel flows continuously, carrying away the heat from the wafer base, and finally achieving the cooling of the chuck.

[0018] Compared to existing technologies that involve direct contact between the electrostatic chuck and the wafer substrate for heat dissipation through contact heat transfer, the wafer chuck assembly provided in this embodiment uses thermal radiation to dissipate heat. The heat from the chuck can be gradually radiated away, and there is a gap between the chuck and the heat-absorbing layer on the wafer substrate. This avoids sudden cooling or even cracking caused by direct contact between the chuck and the wafer substrate with the first cooling channel. Furthermore, the heat-absorbing layer can quickly absorb and transfer the heat radiated by the chuck to the wafer substrate. The coolant flowing in the first cooling channel of the wafer substrate quickly carries away the heat from the wafer substrate, allowing the wafer substrate to cool the heat-absorbing layer. This, in turn, allows the heat-absorbing layer to continuously absorb the heat radiated by the chuck, ultimately cooling the chuck and ensuring its normal operation.

[0019] The wafer chuck assembly temperature control method proposed in this invention employs closed-loop intelligent control logic to acquire the actual temperature of the chuck in real time. Based on the real-time temperature value of the chuck, the flow rate and supply duration of the coolant entering the first cooling channel are controlled until the chuck temperature reaches the set temperature. The heat of the chuck is mainly transferred to the heat-absorbing layer in the form of thermal radiation, and then the heat-absorbing layer transfers the radiated heat of the chuck to the wafer substrate. The coolant in the first cooling channel continuously flows, carrying away the heat from the wafer substrate, ultimately achieving the cooling of the chuck. Attached Figure Description

[0020] Figure 1 This is a schematic cross-sectional view of the wafer chuck assembly described in an embodiment of the present invention during operation; Figure 2 This is a flowchart of the wafer chuck assembly temperature control method according to an embodiment of the present invention; Figure 3 This is a flowchart of step S2 in the wafer chuck assembly temperature control method described in this embodiment of the invention, in which control is performed based on the difference between the actual temperature of the chuck and the set temperature. Figure 4 This is a flowchart illustrating the process of controlling the flow rate and supply duration of coolant entering the first cooling channel based on the difference in the temperature control method for wafer chuck assembly according to an embodiment of the present invention. Figure 5 This is a flowchart illustrating the temperature control method for a wafer chuck assembly according to an embodiment of the present invention, specifically the control based on the temperature rise rate of the chuck.

[0021] In the picture: 10. Wafers; 1. Wafer substrate; 11. First cooling channel; 2. Heat absorption layer; 3. Pad; 4. Chuck; 5. Adhesive layer; 6. Pressure ring; 7. Back pressure sealing ring. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1 See Figure 1 This embodiment provides a wafer chuck assembly that can fix the wafer 10 during the processing of the wafer 10.

[0027] Specifically, in this embodiment, the wafer chuck assembly includes a wafer base 1, a heat-absorbing layer 2, a pad 3, and a chuck 4.

[0028] A first cooling channel 11 is provided inside the wafer substrate 1. After coolant is introduced into the first cooling channel 11, the wafer substrate 1 can be cooled.

[0029] The heat-absorbing layer 2 is disposed on the upper surface of the wafer base 1.

[0030] The pad 3 is placed on the heat-absorbing layer 2.

[0031] The chuck 4 is placed on the pad 3 and there is a gap between it and the heat-absorbing layer 2, so that the heat of the chuck 4 can be radiated to the heat-absorbing layer 2.

[0032] It is understandable that a heating element is installed inside the chuck 4.

[0033] Specifically, the chuck 4 is fixed to the wafer base 1 by the pressure ring 6.

[0034] Specifically, in use, the gap between the chuck 4 and the heat absorption layer 2 of the wafer chuck assembly provided in this embodiment is connected to the sputtering chamber environment to maintain the same gas pressure.

[0035] Optionally, in this embodiment, the number of spacers 3 is multiple. For example, the number of spacers 3 is six. The six spacers 3 are equally spaced along the circumference of the wafer base 1.

[0036] When the wafer chuck assembly provided in this embodiment is working, the heat of the chuck 4 is mainly transferred to the heat absorption layer 2 in the form of thermal radiation, and then the heat absorption layer 2 transfers the heat radiated by the chuck 4 to the wafer base 1. The coolant in the first cooling channel 11 flows continuously, carrying away the heat of the wafer base 1, and finally achieving the cooling of the chuck 4.

[0037] Compared to existing technologies that involve direct contact between the electrostatic chuck and the wafer substrate for heat dissipation through contact heat transfer, the wafer chuck assembly provided in this embodiment uses thermal radiation to dissipate heat from the chuck 4. The heat from the chuck 4 can be gradually radiated away, and there is a gap between the chuck 4 and the heat-absorbing layer 2 on the wafer substrate 1. This avoids the chuck 4 directly contacting the wafer substrate 1 with the first cooling channel 11, which could cause sudden cooling or even cracking. Furthermore, the heat-absorbing layer 2 can quickly absorb and transfer the heat radiated by the chuck 4 to the wafer substrate 1. The coolant flowing in the first cooling channel 11 of the wafer substrate 1 quickly carries away the heat from the wafer substrate 1, allowing the wafer substrate 1 to cool the heat-absorbing layer 2. This allows the heat-absorbing layer 2 to continuously absorb the heat radiated by the chuck 4, ultimately cooling the chuck 4 and ensuring its normal operation.

[0038] Understandably, compared to the surface area of ​​the entire upper surface of the chuck 4, the contact area between the pad 3 and the chuck 4 is very small, and the pad 3 is made of a material with low thermal conductivity. Therefore, the heat transferred from the chuck 4 to the heat-absorbing layer 2 via the pad 3 is almost negligible. The heat from the chuck 4 is mainly transferred to the heat-absorbing layer through thermal radiation.

[0039] Optionally, in this embodiment, the chuck 4 is an electrostatic chuck. When the chuck 4 adsorbs the wafer 10, a back pressure sealing ring 7 is provided between the upper surface of the chuck 4 and the lower surface of the wafer 10. The back pressure sealing ring 7 is made of ceramic.

[0040] The electrostatic chuck uses electrostatic force to hold the wafer 10, preventing the wafer 10 from warping or deforming due to mechanical clamping, ensuring the flatness of the wafer 10 during processing, thereby ensuring the uniformity and quality of semiconductor processes, and reducing the risk of particle contamination.

[0041] During PVD sputtering deposition on wafer 10, the wafer chuck assembly provided in this embodiment is used to fix wafer 10. Under high temperature conditions, continuous plasma bombardment leads to an increase in energy density, causing the temperature of wafer 10 to rise. Although the electrostatic chuck has shut down its internal heating components, the back-blown gas between the electrostatic chuck and wafer 10 rapidly transfers the heat radiated by wafer 10 to the electrostatic chuck, causing the electrostatic chuck to passively heat up. This results in a large deviation between the actual temperature of the electrostatic chuck and the set temperature, leading to an over-temperature alarm on the equipment.

[0042] When using the wafer chuck assembly provided in this embodiment, the heat on the electrostatic chuck can be transferred away in a timely manner, avoiding excessive temperature of the electrostatic chuck and preventing sudden cooling or even cracking of the electrostatic chuck.

[0043] Optionally, in this embodiment, the height of the gap is 0.6mm-1.5mm.

[0044] Further optionally, in this embodiment, the height of the gap is 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm or 1.5mm.

[0045] Setting the height of the gap to the aforementioned dimensions allows the radiant heat from the chuck 4 to be transferred to the heat-absorbing layer 2.

[0046] Specifically, different heights of pads 3 can be selected to achieve fine-tuning of the gap height.

[0047] Optionally, in this embodiment, the thickness of the heat-absorbing layer 2 is 4μm-300μm. For example, the thickness of the heat-absorbing layer 2 is 4μm, 10μm, 50μm, 100μm, 150μm, 200μm, 250μm, or 300μm. Of course, in other embodiments, the thickness of the heat-absorbing layer 2 can also be set to other values ​​as needed.

[0048] Theoretically, the thicker the heat absorption layer 2, the higher the heat absorption efficiency. However, the adhesion of the ceramic heat absorption layer will be worse, making processing more difficult. If the ceramic heat absorption layer is too thick, the gap between the electrostatic chuck and the cooling base will be smaller, making the installation of the electrostatic chuck more difficult.

[0049] Therefore, by using the heat absorption layer 2 of the above thickness, the heat absorption efficiency can be guaranteed, while avoiding excessive processing difficulty and excessive difficulty in installing the electrostatic chuck.

[0050] Specifically, in this embodiment, the heat-absorbing layer 2 is a ceramic heat-absorbing layer. Optionally, in this embodiment, the material of the heat-absorbing layer 2 includes at least one of alumina, chromium oxide, aluminum nitride, zirconium oxide, silicon oxide, and yttrium oxide.

[0051] Specifically, the heat-absorbing layer 2 can be made of any one of aluminum oxide, chromium oxide, aluminum nitride, zirconium oxide, silicon oxide, and yttrium oxide; or it can be a combination of at least two of aluminum oxide, chromium oxide, aluminum nitride, zirconium oxide, silicon oxide, and yttrium oxide.

[0052] In this embodiment, the ceramic heat absorption layer is selected from dielectric materials with high thermal absorption rate and low emissivity, such as alumina, chromium oxide, aluminum nitride, zirconium oxide, silicon oxide and yttrium oxide. The ceramic heat absorption layer can absorb the heat on the electrostatic chuck by thermal radiation through the gaps, and then the excess heat is carried away by the wafer base 1.

[0053] The aforementioned material has the advantages of high thermal absorption rate and low thermal emissivity, which can fully absorb the heat radiated from the chuck 4 and transfer the heat to the wafer substrate 1 in a timely manner.

[0054] Optionally, the thickness, material composition, or thermal conductivity of the heat-absorbing layer 2 can be adjusted to control the heat transfer efficiency and ensure the processing quality of the wafer 10.

[0055] Specifically, in this embodiment, the material of the pad 3 is also ceramic and is different from the material of the heat-absorbing layer 2. For example, in this embodiment, the material of the pad 3 is a high-temperature resistant material with low thermal conductivity, such as zirconium oxide.

[0056] Furthermore, in this embodiment, the wafer chuck assembly also includes an adhesive layer 5, and the heat-absorbing layer 2 is bonded to the upper surface of the wafer base 1 through the adhesive layer 5.

[0057] The adhesive layer 5 enables the heat-absorbing layer 2 to be stably positioned on the wafer substrate 1, preventing the heat-absorbing layer 2 from falling off the wafer substrate 1 during the temperature rise process.

[0058] Optionally, in this embodiment, the adhesive layer 5 is a metal adhesive layer.

[0059] Optionally, in this embodiment, the material of the adhesive layer 5 includes any one or more combinations of nickel-chromium-aluminum-yttrium, titanium, aluminum, copper, molybdenum, tungsten, and stainless steel.

[0060] For example, in this embodiment, the adhesive layer 5 is made of nickel-chromium-aluminum-yttrium (NiCrAlY). The weight percentage of NiCrAlY is 67 / 22 / 10 / 1% wt.%. NiCrAlY is widely used as an intermediate metal transition between high-temperature alloys and insulating layers, and NiCrAlY alloys exhibit good adhesion to various high-temperature alloys. As an adhesive layer, the NiCrAlY coating possesses excellent resistance to high-temperature oxidation, corrosion, wear, and mechanical properties, and is used in the most demanding high-temperature environments to protect heated components from corrosion, wear, and erosion. The NiCrAlY and other metal adhesive layers are located between the stainless steel alloy wafer substrate 1 and the ceramic heat-absorbing layer 2, enhancing the bonding force between the two and preventing the heat-absorbing layer 2 from detaching during heating and cooling processes.

[0061] Optionally, in this embodiment, the thickness of the adhesive layer 5 is 1μm-200μm. For example, the thickness of the adhesive layer 5 is 1μm, 5μm, 10μm, 50μm, 100μm, 150μm, or 200μm. Of course, in other embodiments, the thickness of the adhesive layer 5 can also be set to other values ​​as needed.

[0062] Specifically, in this embodiment, the sum of the thicknesses of the adhesive layer 5 and the heat-absorbing layer 2 is 5μm-500μm. Exemplarily, the sum of their thicknesses can be 5μm, 10μm, 50μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, or 500μm. Of course, in other embodiments, the sum of the thicknesses of the adhesive layer 5 and the heat-absorbing layer 2 can be set to other values ​​as needed.

[0063] The adhesive layer 5 is applied to the upper surface of the wafer substrate 1 by means of plasma spraying, magnetron sputtering, chemical vapor deposition or evaporation.

[0064] The heat-absorbing layer 2 is applied to the upper surface of the adhesive layer 5 by means of plasma spraying, magnetron sputtering, chemical vapor deposition or evaporation.

[0065] Optionally, the upper surface of the heat-absorbing layer 2 is provided with an uneven structure; and / or, A second cooling channel is provided on the upper surface of the heat-absorbing layer 2.

[0066] Specifically, in this embodiment, the upper surface of the heat-absorbing layer 2 is provided with an uneven structure, which makes the surface area of ​​the heat-absorbing layer 2 facing the chuck 4 larger, thereby increasing the effective specific surface area between the heat-absorbing layer 2 and the chuck 4, so that the heat-absorbing layer 2 can accept more heat.

[0067] The upper surface of the heat-absorbing layer 2 can be provided with one or more of the following: texture, microgroove, dot matrix protrusion, or irregular contour.

[0068] By setting the upper surface of the heat-absorbing layer 2 as a non-planar structure with an uneven structure, the defects of limited heat-absorbing surface area and insufficient heat exchange efficiency of planar structures can be avoided. In particular, the phenomenon of interface separation and warping that easily occurs under high-temperature cycling conditions can be avoided.

[0069] Optionally, the upper surface of the adhesive layer 5 is also a non-planar structure to increase its bonding strength with the heat-absorbing layer 2. The bonding strength between the adhesive layer 5 and the heat-absorbing layer 2 is significantly improved, the cross-sectional thermal resistance is reduced, and thermal stress is released, improving the dimensional stability of the structure at high temperatures. Simultaneously, it significantly improves the interface heat conduction efficiency, enabling rapid and uniform heat transfer under high-temperature conditions, reducing the risk of localized overheating. This design does not significantly increase manufacturing difficulty and has good engineering feasibility. Comprehensive analysis shows that the non-planar upper surface design of the adhesive layer 5 and the heat-absorbing layer 2 effectively improves the overall reliability, thermal conductivity, and lifespan of the wafer chuck assembly, meeting the requirements of next-generation semiconductor process equipment for highly stable and heat-dissipating chucks.

[0070] Specifically, in this embodiment, a second cooling channel is provided on the upper surface of the heat-absorbing layer 2, and a coolant supply device is connected to the second cooling channel to supply coolant to the second cooling channel.

[0071] When the coolant flows into the second cooling channel, it can initially cool the heat-absorbing layer 2, improve the heat absorption capacity of the heat-absorbing layer 2, and thus improve the cooling effect on the chuck 4.

[0072] Optionally, the shape of the second cooling channel includes one or more combinations of straight, curved, grid, or spiral shapes.

[0073] Optionally, the second cooling channels are distributed uniformly or non-uniformly on the upper surface of the heat-absorbing layer 2.

[0074] Optionally, a temperature sensor is provided on the chuck 4, and the coolant supply device includes a flow regulation module. The coolant supply device adjusts the flow rate and supply time of the coolant entering the first cooling channel 11 and the second cooling channel according to the detection result of the temperature sensor.

[0075] Specifically, under normal operating conditions, the coolant supply device only supplies coolant to the first cooling channel 11. The chuck 4 dissipates heat through thermal radiation, and the heat-absorbing layer 2 absorbs the heat radiated by the chuck 4 and transfers it normally to the wafer base 1, ensuring orderly heat dissipation.

[0076] To cope with extreme high-temperature conditions, a second cooling channel is pre-set on the upper surface of the heat-absorbing layer 2, and the second cooling channel is connected to the coolant supply device. When the temperature of the chuck 4 exceeds the set safety threshold, the system automatically starts the cooling mechanism, introduces coolant into the second cooling channel, and rapidly and initially cools the heat-absorbing layer 2, thereby sharing the heat dissipation load of the wafer base 1 and preventing excessive heat accumulation.

[0077] This embodiment also provides a PVD sputtering deposition apparatus, which includes the wafer chuck assembly described above.

[0078] Example 2 This embodiment provides a method for temperature control of a wafer chuck assembly. This method can control the temperature of the chuck 4 in the wafer chuck assembly of Embodiment 1.

[0079] See Figure 2 In this embodiment, the temperature control method for the wafer chuck assembly includes the following steps: S1. Real-time acquisition of the actual temperature of chuck 4; S2. Based on the actual temperature of the chuck 4, control the flow rate and supply duration of the coolant entering the first cooling channel 11 until the temperature of the chuck 4 reaches the set temperature.

[0080] The wafer chuck assembly temperature control method provided in this embodiment employs closed-loop intelligent control logic to acquire the actual temperature of the chuck 4 in real time. Based on the real-time temperature value of the chuck 4, the flow rate and supply duration of the coolant entering the first cooling channel 11 are controlled until the temperature of the chuck 4 reaches the set temperature. The heat from the chuck 4 is mainly transferred to the heat-absorbing layer 2 in the form of thermal radiation, and then the heat-absorbing layer 2 transfers the radiated heat from the chuck 4 to the wafer substrate 1. The coolant in the first cooling channel 11 continuously flows, carrying away the heat from the wafer substrate 1, ultimately achieving the cooling of the chuck 4.

[0081] The chuck 4 is cooled by thermal radiation, allowing the heat from the chuck 4 to radiate out gradually. A gap exists between the chuck 4 and the heat-absorbing layer 2 on the wafer substrate 1. This prevents the chuck 4 from directly contacting the wafer substrate 1 with its first cooling channel 11, which could cause sudden cooling or even cracking. Furthermore, the heat-absorbing layer 2 quickly absorbs and transfers the heat radiated by the chuck 4 to the wafer substrate 1. The coolant flowing in the first cooling channel 11 of the wafer substrate 1 rapidly carries away the heat from the wafer substrate 1, thus cooling the heat-absorbing layer 2. This, in turn, allows the heat-absorbing layer 2 to continuously absorb the heat radiated by the chuck 4, ultimately cooling the chuck 4 and ensuring its normal operation.

[0082] Specifically, in this embodiment, in step S2, when the temperature of the chuck 4 is initially detected to have reached the set temperature, the temperature of the chuck 4 is continuously detected. If the temperature change range of the chuck 4 is less than the set range within the set time, it is determined that the temperature of the chuck 4 has reached the set temperature.

[0083] It is understandable that the temperature of chuck 4 will fluctuate in real time when the temperature is detected. Even if the temperature of chuck 4 is initially detected to reach the set temperature, the temperature of chuck 4 may rise in the next second because the wafer chuck assembly is working continuously, leading to misjudgment.

[0084] Therefore, when the temperature of chuck 4 is detected to have reached the set temperature, the temperature of chuck 4 is monitored again. If the temperature change range of chuck 4 is less than the set range within the set time, it indicates that the temperature of chuck 4 is basically stable at this time, and it can be considered that the temperature of chuck 4 has reached the set temperature.

[0085] Optionally, the duration can be set to 60s-180s. For example, the duration can be set to 60s, 70s, 80s, 90s, 110s, 120s, 130s, 140s, 150s, 160s, 170s, or 180s. Of course, in other embodiments, the duration can be set to other values ​​as needed.

[0086] Further, see Figure 3 In this embodiment, step S2 includes: S201. Obtain the difference between the actual temperature and the set temperature of the chuck 4; S202. The flow rate and supply duration of the coolant entering the first cooling channel 11 are controlled based on the difference.

[0087] Further, see Figure 4 In this embodiment, step S202 includes: S2021. Determine whether the difference is less than the first preset difference; If so, proceed to step S2022; If not, proceed to step S2023; S2022, Control the coolant to enter the first cooling channel 11 at a first flow rate, and control the coolant to be continuously supplied for a first duration; S2023. Determine whether the difference is less than the second preset difference; if the second preset difference is greater than the first preset difference; If so, the coolant is controlled to enter the first cooling channel 11 at a second flow rate, and the coolant is controlled to be continuously supplied for a second duration; the second flow rate is greater than the first flow rate, and the second duration is greater than the first duration; If not, the coolant is controlled to enter the first cooling channel 11 at a third flow rate, and the coolant is controlled to be continuously supplied for a third duration; the third flow rate is greater than the second flow rate, and the third duration is greater than the second duration.

[0088] Optionally, in this embodiment, the first preset difference is 5°C; the first flow rate is 0.5L / min-2L / min; and the first duration is 20s-100s. Of course, in other embodiments, the first preset difference, the first flow rate, and the first duration can also be set to other values ​​as needed.

[0089] When the difference is less than the first preset difference, it means that the temperature rise is not large. The coolant is controlled to enter the first cooling channel 11 at the first flow rate, and the coolant is controlled to be continuously supplied for the first duration. That is, slight auxiliary heat dissipation is used to slightly suppress the temperature rise, so that the chuck 4 can return to the target temperature range smoothly.

[0090] Optionally, in this embodiment, the second preset difference is 15°C; the second flow rate is 2L / min-3L / min; and the second duration is 100s-300s. Of course, in other embodiments, the second preset difference, the second flow rate, and the second duration can also be set to other values ​​as needed.

[0091] When the difference is less than the second preset difference, the coolant is controlled to enter the first cooling channel 11 at the second flow rate, and the coolant is controlled to be continuously supplied for the second duration, that is, a medium intensity cooling method is adopted to quickly reduce the temperature difference and prevent the temperature from continuing to rise.

[0092] When the temperature difference is not less than the second preset difference, it indicates that the chuck 4 is severely overheated. At this time, the coolant is controlled to enter the first cooling channel 11 at a third flow rate, and the coolant is continuously supplied for a third duration. That is, a strong forced cooling method is adopted to avoid large temperature differences and excessive thermal stress, thus protecting the chuck 4.

[0093] Optionally, in this embodiment, the third flow rate is 3L / min-4L / min. The third duration is 300s-600s.

[0094] Of course, in other embodiments, the third flow rate and the third duration can also be set to other values ​​as needed.

[0095] Furthermore, in step S2023, when the difference is not less than the second preset difference, the coolant is controlled to enter the first cooling channel 11 at a third flow rate, and the coolant is controlled to be continuously supplied for a third duration; and after the third duration ends, if the actual temperature of the chuck 4 is still greater than the set temperature, the coolant is supplied for a delayed period until the temperature of the chuck 4 reaches the set temperature.

[0096] Furthermore, in this embodiment, a second cooling channel is provided on the upper surface of the heat-absorbing layer 2 in the wafer chuck assembly.

[0097] To further improve the heat dissipation efficiency of the chuck 4, in this embodiment, see... Figure 5 Step S2 also includes: S211. Obtain the temperature rise rate of chuck 4 based on its actual temperature. S212. Determine whether the temperature rise rate is less than the first value; If so, proceed to step S213; If not, proceed to step S214; S213. Control the coolant to enter the second cooling channel at a fourth flow rate and supply coolant to the second cooling channel in an intermittent supply mode. S214. Determine if the temperature rise rate is less than the second value; if the second value is greater than the first value. If so, control the coolant to enter the second cooling channel at a fifth flow rate, and control the supply duration of the coolant entering the second cooling channel to a fourth duration; If not, control the coolant to enter the second cooling channel at a sixth flow rate, and control the supply duration of the coolant entering the second cooling channel to be a fifth duration, where the sixth flow rate is greater than the fifth flow rate and the fifth duration is greater than the fourth duration.

[0098] Optionally, in this embodiment, the diameter of the second cooling channel is 0.5mm-2mm.

[0099] To prevent the ceramic surface of the chuck 4 from cracking during rapid cooling and heating, the heating rate of the heated chuck 4 must be strictly controlled to be ≤2℃ / min.

[0100] In step S2, through steps S211-S214, slow heat exchange and precise temperature control of chuck 4 are achieved.

[0101] Optionally, in this embodiment, in step S213, the first value is 1℃ / min; the fourth flow rate is 0.04L / min-0.1L / min; in step S213, the coolant is supplied to the second cooling channel in an intermittent supply mode, and the duration of a single supply is 20s-60s.

[0102] In step S212, if the temperature rise rate is less than the first value, it indicates that the temperature rise of chuck 4 is small. At this time, step S213 is executed to remove residual heat using a small amount of cooling, maintain a stable temperature, and achieve no overcooling and no temperature fluctuation.

[0103] In step S212, if the temperature rise rate is not less than the first value, then step S214 is executed.

[0104] In step S214, if the temperature rise rate is less than the second value, it indicates that the temperature rise fluctuation of the chuck 4 is moderate. The coolant is then controlled to enter the second cooling channel at a fifth flow rate, and the supply duration of the coolant entering the second cooling channel is controlled to a fourth duration. This effectively suppresses the temperature rise and reduces the difference between the actual temperature and the target temperature.

[0105] Optionally, the second value is 3℃ / min; the fifth flow rate is 0.08L / min-0.2L / min; and the fourth duration is 60s-180s.

[0106] Of course, in other embodiments, the second value, the fifth flow rate, and the fourth duration can also be set to other values ​​as needed.

[0107] In step S214, if the temperature rise rate is not less than the second value, it indicates that the chuck 4 is heating up quickly. At this time, the coolant is controlled to enter the second cooling channel at the sixth flow rate, and the supply time of the coolant entering the second cooling channel is controlled to be the fifth duration. The sixth flow rate is greater than the fifth flow rate, and the fifth duration is greater than the fourth duration.

[0108] Optionally, the sixth flow rate is 0.2 L / min to 0.6 L / min; the fifth duration is 180 s to 360 s.

[0109] Of course, in other embodiments, the sixth flow rate and the fifth duration can also be set to other values ​​as needed.

[0110] Optionally, in this embodiment, at least two temperature measuring points are provided on the chuck 4, and each temperature measuring point is provided with a temperature sensor.

[0111] In step S211, the temperature values ​​obtained from all temperature measurement points are processed to obtain the actual temperature of the chuck 4.

[0112] Furthermore, when measuring the temperature at a point, a temperature value is acquired if the value measured by the temperature sensor remains constant within the effective time. This setting ensures the stability and validity of the data when measuring the temperature at the point.

[0113] Optionally, the effective time is 5s-10s. For example, the effective time is 5s, 6s, 7s, 8s, 9s or 10s.

[0114] Specifically, in this embodiment, two temperature measuring points are provided on the chuck 4. The chuck 4 employs a dual-zone heating structure to control the temperature of the wafer 10, and these two zones are two concentric rings or grid-like areas. A temperature measuring point is provided for each zone.

[0115] More specifically, in this embodiment, two temperature measurement points are located at a distance of 50 mm and 129 mm from the internal center point, respectively. Based on the existing method, an additional temperature measurement point is added at a radius of 90 mm in the middle ring area to collect the temperature of the middle ring area of ​​the electrostatic chuck, covering the temperature gradient of the entire region and avoiding localized, one-sided characterization, thereby enabling fine-tuning of the temperature in different areas of the wafer.

[0116] Of course, in other embodiments, the number of temperature measuring points can also be three, four or other, depending on the needs, and no further restrictions are imposed here.

[0117] Specifically, a temperature measuring point can be added 90mm from the internal center point to collect the temperature of the middle ring area of ​​the chuck 4, cover the temperature gradient of the entire area, avoid local single-point partial characterization, and thus achieve fine adjustment of the temperature of different areas of the chuck 4.

[0118] When processing the temperature values ​​obtained from all temperature measurement points, the data processing methods can include taking the average, taking the mode, or other data processing methods.

[0119] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A wafer chuck assembly, characterized in that, include: A wafer substrate, wherein a first cooling channel is provided within the wafer substrate; A heat-absorbing layer is disposed on the upper surface of the wafer substrate; A pad is disposed on the heat-absorbing layer; A chuck is disposed on the pad and there is a gap between it and the heat-absorbing layer, so that the heat of the chuck can be radiated to the heat-absorbing layer.

2. The wafer chuck assembly according to claim 1, characterized in that, The wafer chuck assembly also includes an adhesive layer, and the heat-absorbing layer is bonded to the upper surface of the wafer base via the adhesive layer.

3. The wafer chuck assembly according to claim 1, characterized in that, The upper surface of the heat-absorbing layer is provided with an uneven structure; and / or, The upper surface of the heat-absorbing layer is provided with a second cooling channel.

4. The wafer chuck assembly according to any one of claims 1-3, characterized in that, The heat-absorbing layer is made of at least one of aluminum oxide, chromium oxide, aluminum nitride, zirconium oxide, silicon oxide, and yttrium oxide.

5. The wafer chuck assembly according to any one of claims 1-3, characterized in that, The height of the gap is 0.6mm-1.5mm.

6. A method for temperature control of a wafer chuck assembly, characterized in that, Controlling the temperature of the chuck in the wafer chuck assembly according to any one of claims 1-5 includes the following steps: S1. Real-time acquisition of the actual temperature of the chuck; S2. Based on the actual temperature of the chuck, control the flow rate and supply duration of the coolant entering the first cooling channel until the temperature of the chuck reaches the set temperature.

7. The wafer chuck assembly temperature control method according to claim 6, characterized in that, Step S2 includes: S201. Obtain the difference between the actual temperature and the set temperature of the chuck; S202. Control the flow rate and supply duration of the coolant entering the first cooling channel based on the difference.

8. The wafer chuck assembly temperature control method according to claim 7, characterized in that, Step S202 includes: S2021. Determine whether the difference is less than a first preset difference; If so, proceed to step S2022; If not, proceed to step S2023; S2022. Control the coolant to enter the first cooling channel at a first flow rate, and control the coolant to be continuously supplied for a first duration; S2023. Determine whether the difference is less than a second preset difference; the second preset difference is greater than the first preset difference. If so, the coolant is controlled to enter the first cooling channel at a second flow rate, and the coolant is controlled to be continuously supplied for a second duration; the second flow rate is greater than the first flow rate, and the second duration is greater than the first duration; If not, the coolant is controlled to enter the first cooling channel at a third flow rate, and the coolant is controlled to be continuously supplied for a third duration; the third flow rate is greater than the second flow rate, and the third duration is greater than the second duration.

9. The wafer chuck assembly temperature control method according to claim 7, characterized in that, A second cooling channel is provided on the upper surface of the heat-absorbing layer in the wafer chuck assembly; Step S2 further includes: S211. Obtain the temperature rise rate of the chuck based on its actual temperature; S212. Determine whether the temperature rise rate is less than the first value; If so, proceed to step S213; If not, proceed to step S214; S213. Control the coolant to enter the second cooling channel at a fourth flow rate, and supply the coolant to the second cooling channel in an intermittent supply mode. S214. Determine whether the temperature rise rate is less than the second value; the second value is greater than the first value. If so, control the coolant to enter the second cooling channel at a fifth flow rate, and control the supply duration of the coolant entering the second cooling channel to a fourth duration; If not, the coolant is controlled to enter the second cooling channel at a sixth flow rate, and the supply duration of the coolant entering the second cooling channel is controlled to be a fifth duration, wherein the sixth flow rate is greater than the fifth flow rate, and the fifth duration is greater than the fourth duration.

10. The wafer chuck assembly temperature control method according to any one of claims 6-9, characterized in that, At least two temperature measuring points are provided on the chuck, and each temperature measuring point is provided with a temperature sensor. In step S211, the temperature values ​​obtained from all the temperature measurement points are processed to obtain the actual temperature of the chuck.

11. The wafer chuck assembly temperature control method according to claim 10, characterized in that, When measuring the temperature at the temperature measurement point, if the value measured by the temperature sensor remains unchanged within the effective time, a temperature value is obtained.

12. The wafer chuck assembly temperature control method according to any one of claims 6-9, characterized in that, In step S2, when the temperature of the chuck is initially detected to have reached the set temperature, the temperature of the chuck is continuously detected. If the temperature change range of the chuck is less than the set range within the set time period, it is determined that the temperature of the chuck has reached the set temperature.

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