Electrostatic chuck based on helium cooling and plasma processing apparatus

Abstract

The application relates to the technical field of wafer processing equipment, in particular to a helium-cooled electrostatic chuck and a plasma processing equipment, which comprises a chuck, an edge liquid flow channel, a helium gas guide one, a center liquid flow channel and a helium gas guide two, and a heat exchange cavity is formed between the upper surface of the chuck and a wafer carried thereon; the chuck body comprises a center chuck, an edge chuck and a heat insulation ring; the edge liquid flow channel and the helium gas guide one are arranged in the edge chuck; the center liquid flow channel and the helium gas guide two are arranged in the center chuck, and the gas outlet end of the helium gas guide two is communicated with the heat exchange cavity to convey helium gas into the heat exchange cavity; the center chuck and the edge chuck are arranged, the heat insulation ring is additionally arranged between the two, independent helium gas guides and liquid cooling flow channels are respectively arranged for the two regions, heat in the center region of the wafer is only conducted to the center liquid flow channel for heat exchange through the helium gas in the center chuck, and heat in the edge region is only conducted to the edge liquid flow channel for heat exchange through the helium gas in the edge chuck.

Description

Technical Field

[0001] This invention relates to the field of wafer processing equipment technology, and more particularly to an electrostatic chuck and plasma processing equipment based on helium cooling. Background Technology

[0002] In semiconductor dry etching, especially ICP dry etching, electrostatic chucks commonly employ an integrated cooling method combining liquid cooling channels and back-blown helium to simultaneously clamp and dissipate heat from the back of the wafer. Since the heat released from plasma bombardment and chemical reactions is primarily concentrated on the wafer surface, heat must be transferred sequentially through the ceramic functional layer, the back-blown helium interface, and the chuck substrate to the internal liquid cooling channels. Along this heat transfer path, the wafer naturally exhibits radial temperature differences determined by process characteristics. However, existing electrostatic chucks mostly employ an integral ceramic layer and a through-type liquid cooling channel structure, with the helium back cooling and liquid cooling channels coupled radially, making it impossible to independently control the heat transfer paths between the wafer's central and edge regions. Summary of the Invention

[0003] This invention relates to an electrostatic chuck and plasma processing equipment based on helium cooling. The purpose is to address the shortcomings of existing electrostatic chucks with integral structures where the helium back cooling and liquid cooling channels are radially coupled, making it impossible to independently control the heat transfer paths between the wafer center and the edge, which makes it difficult to eliminate the radial temperature gradient that naturally exists in plasma processes.

[0004] To achieve the above objectives, the present invention provides an electrostatic chuck based on helium cooling, comprising a chuck, an edge liquid flow channel, a helium flow channel one, a central liquid flow channel and a helium flow channel two, wherein the upper surface of the chuck and the wafer supported thereon form a heat exchange cavity. The suction cup includes a center suction cup, an edge suction cup, and a heat insulation ring. The center suction cup and the edge suction cup correspond to the central region and the edge region of the wafer, respectively. The edge suction cup is arranged around the outside of the center suction cup, and the heat insulation ring is arranged between the center suction cup and the edge suction cup to block the heat transfer channel between the center suction cup and the edge suction cup. Both the edge liquid flow channel and the first helium gas guide channel are located inside the edge suction cup, and the outlet end of the first helium gas guide channel is connected to the heat exchange cavity to deliver helium gas into the heat exchange cavity. The heat of the edge region is conducted to the edge suction cup by the helium gas, and then the edge region is cooled by the cooling liquid in the edge liquid flow channel. Both the central liquid flow channel and the second helium gas guide channel are located inside the central suction cup. The outlet end of the second helium gas guide channel is connected to the heat exchange chamber to deliver helium gas into the heat exchange chamber. The heat of the central region is conducted to the central suction cup by the helium gas, and then the central region is cooled by the cooling liquid in the central liquid flow channel.

[0005] Optionally, the electrostatic chuck further includes an annular extension, which extends circumferentially at the top of the heat insulation ring and extends away from the top of the heat insulation ring and is higher than the upper surface of the chuck. The annular extension divides the heat exchange cavity into a central sub-heat exchange cavity corresponding to the central region and an edge sub-heat exchange cavity corresponding to the edge region. The outlet end of the first helium gas channel is connected to the edge sub-heat exchange cavity, and the outlet end of the second helium gas channel is connected to the central sub-heat exchange cavity, so as to separate the helium gas injected into the edge sub-heat exchange cavity and the central sub-heat exchange cavity.

[0006] Optionally, both the central suction cup and the edge suction cup include a suction cup body, an adhesive layer, an aluminum nitride ceramic layer, and an oxide layer; The oxide layer is fixed to the top of the suction cup body and forms a sealed cavity between it and the suction cup body; The aluminum nitride ceramic layer and the adhesive layer are disposed in the sealed cavity, and the aluminum nitride ceramic layer is fixed to the top of the suction cup body by the adhesive layer; The first helium gas channel and the second helium gas channel respectively pass through the corresponding suction cup body, the adhesive layer, the aluminum nitride ceramic layer and the oxide layer.

[0007] Optionally, the electrostatic chuck further includes an oxide ring, which comprises a central sub-ring and an edge sub-ring; The central sub-ring is coaxially disposed at the outlet end of the helium gas channel two, and the orthographic projection structure of the central sub-ring on the inner sidewall of the helium gas channel two covers the sidewall of the aluminum nitride ceramic layer. The edge sub-ring is coaxially disposed at the outlet end of the helium gas channel one, and the orthographic projection structure of the edge sub-ring on the inner sidewall of the helium gas channel one covers the sidewall of the aluminum nitride ceramic layer to prevent the aluminum nitride ceramic layer from contacting the helium gas.

[0008] Optionally, both the central suction cup and the edge suction cup further include at least one aluminum nitride ceramic ring. Each aluminum nitride ceramic ring is arranged around the central axis of the suction cup with different radii within the suction cup body. The top of each aluminum nitride ceramic ring is connected to the bottom of the aluminum nitride ceramic layer and extends towards the bottom of the suction cup body along the central axis, so as to conduct the heat on the aluminum nitride ceramic layer to the bottom of the suction cup body along each aluminum nitride ceramic ring.

[0009] Optionally, the electrostatic chuck further includes a temperature regulating component one and a temperature regulating component two; The temperature regulating element is located at the outlet end of the helium gas channel and connected to an external power source, so that when the power is on, the temperature of the edge region is kept within a first preset temperature by adjusting the temperature of the helium gas entering the edge sub-heat exchange cavity. The second temperature regulating element is located at the outlet end of the second helium gas channel and is connected to an external power source. When powered on, it adjusts the temperature of the helium gas entering the central sub-heat exchange cavity to keep the temperature of the central region within a second preset temperature.

[0010] Optionally, the electrostatic chuck further includes an elastic telescopic component one and an elastic telescopic component two; The elastic expansion member is fixed around the outer wall of the temperature regulating member. A flow channel for helium to pass through is formed between the outer wall of the elastic expansion member and the inner wall of the outlet end of the helium gas guide. The elastic expansion member is made of a material that expands and contracts with temperature, so that it deforms after absorbing the heat generated by the temperature regulating member, thereby adjusting the radial flow area of ​​the flow channel. The second elastic expansion member is fixed around the outer wall of the second temperature regulating member. A flow channel for helium to pass through is formed between the outer wall of the second elastic expansion member and the inner wall of the outlet end of the second helium gas guide. The second elastic expansion member is made of a material that expands and contracts with temperature, so that it deforms after absorbing the heat generated by the second temperature regulating member, thereby adjusting the radial flow area of ​​the flow channel.

[0011] Optionally, the electrostatic chuck further includes several connector 1 and several connector 2, wherein both connector 1 and connector 2 are made of elastic material; Several connectors are arranged circumferentially at intervals in the outlet end of the helium channel, and the two ends of each connector are respectively fixed to the inner side wall of the outlet end of the helium channel and the outer side wall of the elastic telescopic member. Several connectors are arranged circumferentially at intervals inside the outlet end of the helium gas channel, and the two ends of each connector are respectively fixed to the inner side wall of the outlet end of the helium gas channel and the outer side wall of the elastic telescopic member.

[0012] Optionally, the electrostatic chuck further includes an elastic restraint member one and an elastic restraint member two; The elastic restraint member is fixed around at least part of the outer wall of the elastic telescopic member to make the elastic telescopic member deform uniformly under the circumferential restraint force of the elastic restraint member. The second elastic restraint member is fixed around at least part of the outer wall of the second elastic telescopic member to cause the second elastic telescopic member to deform uniformly under the circumferential restraint force of the second elastic restraint member.

[0013] Optionally, the helium gas channel one includes an edge gas inlet channel, a connecting channel one, and several injection slots one. The edge gas inlet channel is connected to an external helium gas supply source. The several injection slots one are all connected to the edge gas inlet channel through the connecting channel one. The several injection slots one are arranged on the edge suction cup with different radii and centered on the central axis of the suction cup. The outlet end of each injection slot one is connected to the edge sub-heat exchange chamber.

[0014] Optionally, the second helium gas channel includes a central inlet channel, a second connecting channel, and several second injection slots. The central inlet channel is connected to an external helium supply source. The several second injection slots are connected to the central inlet channel through the second connecting channel. The several second injection slots are arranged on the central suction cup with different radii, centered on the central axis of the suction cup. The outlet end of each second injection slot is connected to the central sub-heat exchange chamber.

[0015] To achieve the above objectives, the present invention also provides a plasma processing device, including a reaction chamber, a base, and the helium-cooled electrostatic chuck, wherein the helium-cooled electrostatic chuck is disposed in the reaction chamber via the base.

[0016] The beneficial effects of this invention are as follows: This invention addresses the problems of radial coupling between helium cooling and liquid cooling channels in the existing monolithic electrostatic chuck structure, which makes it impossible to independently control the heat transfer paths between the wafer center and edge, and thus difficult to eliminate radial temperature gradients caused by the process. By setting up separate central and edge chucks and adding a heat insulation ring between them to block the cross-regional heat transfer channel, and by configuring independent helium channels and liquid cooling channels for each region, the heat in the wafer center region is conducted to the central liquid channel only through the helium in the central chuck, and the heat in the edge region is conducted to the edge liquid channel only through the helium in the edge chuck. Structurally, this achieves physical isolation and independent temperature control of the cooling circuits at different radial positions of the wafer, which can accurately match the differentiated heat generation requirements of the central and edge regions and effectively smooth out the radial temperature gradient of the wafer. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a plasma processing device in some embodiments of the present invention; Figure 2 for Figure 1 The diagram shows the structure of the electrostatic chuck. Figure 3 for Figure 2 An enlarged schematic diagram of the structure at position A in the diagram; Figure 4 for Figure 3 An enlarged schematic diagram of the structure at position B in the diagram.

[0018] Explanation of reference numerals in the attached figures: 1. Reaction chamber; 2. Base; 3. Suction cup body; 31. Central suction cup; 32. Edge suction cup; 33. Heat insulation ring; 34. Adhesive layer; 35. Aluminum nitride ceramic layer; 36. Oxide layer; 4. Edge liquid flow channel; 5. Helium gas guide channel one; 51. Edge gas inlet channel; 52. Injection tank one; 53. Connecting channel one; 6. Central liquid flow channel; 7. Helium gas guide channel two; 71. Central gas inlet channel; 72. Injection tank two; 73. Connecting channel two; 8. Aluminum nitride ceramic ring; 9. Oxide ring; 10. Temperature regulating component one; 11. Elastic telescopic component one; 12. Elastic restraint component one; 13. Connecting component one. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, but do not exclude other elements or objects.

[0020] This invention relates to an electrostatic chuck and plasma processing equipment based on helium cooling. The purpose is to address the shortcomings of existing electrostatic chucks with integral structures where the helium back cooling and liquid cooling channels are radially coupled, making it impossible to independently control the heat transfer paths between the wafer's central and edge regions, thus making it difficult to eliminate the radial temperature gradient naturally present in plasma processes.

[0021] To address the problems existing in the prior art, embodiments of the present invention provide an electrostatic chuck based on helium cooling, such as... Figure 1 and Figure 2 As shown, the helium-cooled electrostatic chuck includes a chuck, an edge liquid flow channel 4, a helium gas guide channel 1 5, a central liquid flow channel 6, and a helium gas guide channel 2 7. The upper surface of the chuck and the wafer it carries form a heat exchange cavity.

[0022] In some embodiments, such as Figure 2As shown, the suction cup includes a central suction cup 31, an edge suction cup 32, and a heat insulation ring 33. The central suction cup 31 and the edge suction cup 32 correspond to the central region and the edge region of the wafer, respectively. The edge suction cup 32 is arranged around the outside of the central suction cup 31, and the heat insulation ring 33 is arranged between the central suction cup 31 and the edge suction cup 32 to block the heat transfer channel between the central suction cup 31 and the edge suction cup 32.

[0023] By embedding a heat insulation ring 33 between the central suction cup 31 and the edge suction cup 32, the lateral heat conduction link between the central region and the edge region of the wafer at the suction cup level is completely severed from the physical structure. This makes the heat transfer chains formed by the central region and the edge region after carrying the wafer heat exchange completely independent and do not cross heat.

[0024] In some embodiments, such as Figure 2 As shown, the edge liquid flow channel 4 and the helium gas guide channel 5 are both located inside the edge suction cup 32, and the outlet end of the helium gas guide channel 5 is connected to the heat exchange chamber to transport helium gas into the heat exchange chamber. The heat of the edge region is conducted to the edge suction cup 32 by the helium gas, and then the edge region is cooled by the cooling liquid in the edge liquid flow channel 4.

[0025] In some embodiments, such as Figure 2 As shown, the central liquid flow channel 6 and the second helium gas guide channel 7 are both located inside the central suction cup 31, and the outlet end of the second helium gas guide channel 7 is connected to the heat exchange chamber to deliver helium gas into the heat exchange chamber. The heat of the central region is conducted to the central suction cup 31 by the helium gas, and then the central region is cooled by the cooling liquid in the central liquid flow channel 6.

[0026] After integrating the helium gas channel and the liquid flow channel into a single unit with separate central and edge regions, the central and edge regions each form an independent cooling closed loop that does not interfere with each other. The helium gas channel 5 and the edge liquid flow channel 4 in the edge region are specifically designed for the higher heat load at the wafer edge during plasma etching. They construct a dedicated path of "edge back-blown helium heat extraction, edge chuck 32 heat conduction, and edge liquid flow channel 4 heat exhaustion". This can independently enhance the cooling intensity of the edge region to suppress local overheating without affecting the central region of the wafer. The helium gas channel 7 and the central liquid flow channel 6 in the central region lock in the heat in the central region, preventing the temperature from being deviated by the heat exchange fluctuations in the edge region and maintaining the stability of the process environment in the central region. The two closed loops operate in parallel under the obstruction of the heat insulation ring 33, so that the central region and the edge region no longer share the same set of heat conduction links. They can adjust the helium pressure difference and coolant parameters according to their respective heat load differences, and can also work together to converge the temperature of the central region and the edge region to the same target range. This moves from independent temperature control of each zone to overall temperature field equilibrium, and finally eliminates the coupling interference of "adjusting one side affects the whole" in the traditional integrated structure, thus achieving active flattening of the radial temperature gradient of the wafer.

[0027] In one embodiment, the electrostatic chuck further includes an annular extension, which is preferably a ring-shaped structure.

[0028] In one embodiment, the annular extension extends circumferentially to the top of the heat insulation ring 33, and the top of the annular extension extends away from the top of the heat insulation ring 33 and is higher than the upper surface of the suction cup; it can be understood that the size and shape of the annular extension are the same as those of the heat insulation ring 33.

[0029] In one embodiment, the annular extension divides the heat exchange cavity into a central sub-heat exchange cavity corresponding to the central region and an edge sub-heat exchange cavity corresponding to the edge region. The outlet end of the helium gas guide 5 is connected to the edge sub-heat exchange cavity, and the outlet end of the helium gas guide 7 is connected to the central sub-heat exchange cavity, so as to separate the helium gas injected into the edge sub-heat exchange cavity and the central sub-heat exchange cavity.

[0030] In this embodiment, the annular extension protrudes upward from the top of the heat insulation ring 33 and extends above the upper surface of the chuck. Physically, this rigidly splits the originally continuous wafer back-side heat exchange cavity into a central sub-heat exchange cavity and an edge sub-heat exchange cavity. This ensures that the helium injected through helium channel 2 7 only fills the back of the central region, and the helium injected through helium channel 1 5 only fills the back of the edge region. The two streams of helium are completely separated radially by the annular extension and cannot mix. This, together with the heat insulation ring 33 blocking the lateral heat conduction of the chuck and the independent liquid flow channels for heat dissipation in the central and edge regions, forms a triple decoupling of "gas phase interface isolation, solid phase thermal resistance isolation, and independent liquid phase circulation." This structure ensures that the back-blown helium pressure and flow rate in the central and edge regions can be set separately to match their respective heat loads (e.g., the edge region requires high flow rate and strong cooling, while the central region requires low disturbance and slight cooling), and also avoids temperature control distortion caused by the flow of helium from the high-pressure side to the low-pressure side.

[0031] In one embodiment, such as Figure 3 As shown, both the central suction cup 31 and the edge suction cup 32 include a suction cup body 3, an adhesive layer 34, an aluminum nitride ceramic layer 35, and an oxide layer 36.

[0032] In one embodiment, such as Figure 3 As shown, the oxide layer 36 is fixed to the top of the suction cup body 3 and forms a sealed cavity between it and the suction cup body 3; the aluminum nitride ceramic layer 35 and the adhesive layer 34 are disposed in the sealed cavity, and the aluminum nitride ceramic layer 35 is fixed to the top of the suction cup body 3 through the adhesive layer 34.

[0033] In this embodiment, although the aluminum nitride ceramic layer 35 has high thermal conductivity, in the high-temperature plasma process environment containing active particles, its grain boundaries easily adsorb water vapor and undergo hydrolysis to generate ammonia and aluminum oxide, leading to a decrease in the thermal conductivity of the ceramic layer or even structural loosening and peeling. By enclosing the aluminum nitride ceramic layer 35 and the adhesive layer 34 in a sealed cavity through the oxide layer 36 and the chuck body 3, the aluminum nitride ceramic layer 35 and the adhesive layer 34 are completely encapsulated in the sealed cavity, so that the aluminum nitride ceramic layer 35 is completely isolated from the process environment of the reaction chamber 1. In particular, it blocks the direct contact between the fluorine-containing and chlorine-containing plasma and its by-products, process residual water vapor and the surface of the aluminum nitride ceramic layer 35, fundamentally inhibiting the hydrolysis and decomposition reaction of the aluminum nitride ceramic layer 35. At the same time, the sealed cavity provides a sealed and stable working environment for the adhesive layer 34, avoiding the aging and failure of the adhesive under long-term heat and atmospheric corrosion. It not only retains the high thermal conductivity of the aluminum nitride ceramic layer 35 to efficiently transfer the wafer heat downward, but also significantly extends the service life of the electrostatic chuck functional layer.

[0034] In one embodiment, such as Figure 3 As shown, the helium gas channel 1 5 and the helium gas channel 2 7 respectively penetrate the corresponding suction cup body 3, the adhesive layer 34, the aluminum nitride ceramic layer 35 and the oxide layer 36.

[0035] In one embodiment, such as Figure 4 As shown, the electrostatic chuck further includes an oxide ring 9, which comprises a central sub-ring and an edge sub-ring. Both the central sub-ring and the edge sub-ring have a ring-shaped structure. The oxide ring 9 and the oxide layer 36 are made of the same material, preferably alumina ceramic.

[0036] In one embodiment, such as Figure 4 As shown, the central sub-ring is coaxially positioned at the outlet end of the helium gas channel 2 7, and the orthographic projection of the central sub-ring on the inner sidewall of the helium gas channel 2 7 covers the sidewall of the aluminum nitride ceramic layer 35. The central sub-ring coaxially covers the sidewall of the aluminum nitride ceramic layer 35 at the outlet end of the helium gas channel 2 7, ensuring that the back-blown helium in the central region is in contact with the central sub-ring throughout the process without touching the aluminum nitride ceramic layer 35. This prevents the aluminum nitride ceramic layer 35 from being hydrolyzed and decomposed due to trace amounts of water vapor in the helium or the backflow atmosphere in the chamber. This strengthens the lateral anti-corrosion barrier of the functional layer in the central region at the cost of minimal thermal resistance, ensuring long-term thermal stability of the central cooling circuit.

[0037] In one embodiment, such as Figure 4 As shown, the edge sub-ring is coaxially arranged at the outlet end of the helium gas guide 5, and the orthographic projection structure of the edge sub-ring on the inner sidewall of the helium gas guide 5 covers the sidewall of the aluminum nitride ceramic layer 35 to prevent the aluminum nitride ceramic layer 35 from contacting helium. The edge sub-ring also forms a full projection coverage of the sidewall of the aluminum nitride ceramic layer 35 on the inner sidewall of the outlet end of the helium gas guide 5 in a coaxial arrangement, ensuring that the back-blown helium in the edge area is always isolated by the alumina edge sub-ring during its outflow, preventing it from directly contacting the surface of the aluminum nitride ceramic layer 35. This, in conjunction with the central sub-ring, achieves complete airtight protection of the sidewalls of the two-zone aluminum nitride ceramic layer 35. Especially under conditions of higher edge heat load and larger helium flow, it can effectively block the hydrolysis and decomposition of the aluminum nitride ceramic layer 35 induced by water vapor and active atmosphere, ensuring long-term stable thermal conductivity of the edge cooling circuit and preventing contamination of the process cavity.

[0038] In one embodiment, such as Figure 3 As shown, both the central suction cup 31 and the edge suction cup 32 further include at least one aluminum nitride ceramic ring 8. The aluminum nitride ceramic ring 8 is preferably a ring structure, and the ring structure has a certain height.

[0039] In one embodiment, such as Figure 3As shown, each of the aluminum nitride ceramic rings 8 is arranged around the central axis of the suction cup with different radii within the suction cup body 3. The top of each aluminum nitride ceramic ring 8 is connected to the bottom of the aluminum nitride ceramic layer 35 and extends towards the bottom of the suction cup body 3 along the central axis, so as to conduct the heat on the aluminum nitride ceramic layer 35 to the bottom of the suction cup body 3 along each aluminum nitride ceramic ring 8.

[0040] In this embodiment, a multi-layered aluminum nitride ceramic ring 8 with different radii is arranged around the central axis of the suction cup. Extending axially downward from the bottom surface of the top aluminum nitride ceramic layer 35, it constructs a multi-channel, large-section vertical heat-conducting array within the suction cup body 3. The heat transferred from the wafer to the surface of the aluminum nitride ceramic layer 35 via the helium interface is dispersed along the shortest axial path and introduced into the bottom of the suction cup, where it is then carried away by the coolant in the corresponding liquid flow channels. Compared to a single aluminum nitride ceramic layer 35 that expands heat laterally and then turns back downward, this structure significantly shortens the heat conduction distance and increases the heat conduction flow area. This reduces the interfacial thermal resistance between the aluminum nitride ceramic layer 35 and the liquid flow channel. Furthermore, the multi-radius ring arrangement allows heat in the central and edge regions to flow downward along their respective aluminum nitride ceramic rings 8 without intersecting with adjacent regions. This, in conjunction with the partitioning and blocking of the heat insulation ring 33, further enhances the independent heat exchange efficiency of the central and edge regions and improves the radial temperature control response speed.

[0041] In one embodiment, such as Figure 4 As shown, the electrostatic chuck also includes a temperature regulating component 10 and a temperature regulating component 2; the structure of both the temperature regulating component 10 and the temperature regulating component 2 is preferably a miniature electric heating ring.

[0042] In one embodiment, such as Figure 4 As shown, the temperature regulating component 10 is disposed at the outlet end of the helium gas guide 5 and connected to an external power supply. The temperature regulating component 10 is preferably coaxially disposed inside the outlet end of the helium gas guide 5 so that when energized, the temperature of the edge region is kept within a first preset temperature by adjusting the temperature of the helium gas entering the edge sub-heat exchange cavity.

[0043] In this embodiment, the temperature regulating element 10 is arranged at the outlet end of the helium gas guide 5, adjacent to the inlet end of the edge sub-heat exchange cavity. After being powered on, it can perform in-situ heating and fine adjustment of the helium gas about to enter the edge sub-heat exchange cavity. Without changing the reference heat exchange capacity of the edge liquid cooling channel, it can separately compensate for the overcooling caused by the strong heat dissipation after the heat insulation partition or the fluctuation of plasma heat load in the edge area, so that the temperature of the edge area is locked within the first preset temperature.

[0044] In one embodiment, such as Figure 4As shown, the second temperature regulating element is located at the outlet end of the second helium gas channel 7 and is connected to an external power supply, preferably coaxially arranged; so that when energized, the temperature of the central region is kept within a second preset temperature by adjusting the temperature of the helium gas entering the central sub-heat exchange cavity.

[0045] The second temperature regulating component is coaxially located at the outlet end of the second helium gas channel 7, so that the heating surface and the helium gas flow section are concentrically aligned. When the helium gas passes through, it is heated evenly without local cold edges or hot spots, avoiding radial temperature unevenness of the central sub-heat exchange cavity caused by eccentric arrangement. After being powered on, it performs in-situ overall temperature regulation on the central back-blown helium gas flowing through it, and can independently lock the central area at the second preset temperature, decoupled and coordinated with the edge temperature regulating component 10.

[0046] In one embodiment, the second preset temperature and the first preset temperature can be the same or different. Specifically, when the wafer process requires a high degree of radial temperature uniformity, the second preset temperature and the first preset temperature can be set to the same value, so that the temperature of the central region and the edge region converges synchronously to the same target, eliminating the radial temperature gradient to the greatest extent and ensuring the uniformity of etching, deposition and other processes of the entire wafer. When the process requires a specific radial temperature distribution (such as for certain special pattern structures, the temperature of the central region needs to be slightly higher or slightly lower than that of the edge region to optimize the process effect), the two can be set to different preset temperatures. The independent temperature control components 10 and 2 for the central region and the edge region can be used to adjust the temperature of the helium gas in the corresponding regions, flexibly adapting to the differentiated process thermal requirements. While ensuring the accuracy of zoned temperature control, the adaptability of the electrostatic chuck to different process scenarios is expanded.

[0047] In one embodiment, such as Figure 4 As shown, the electrostatic chuck also includes an elastic telescopic component 11 and an elastic telescopic component 2; both the elastic telescopic component 11 and the elastic telescopic component 2 are preferably annular structures, and the materials of both the elastic telescopic component 11 and the elastic telescopic component 2 are preferably shape memory alloys or thermosensitive polymers with high coefficients of thermal expansion.

[0048] In one embodiment, such as Figure 4 As shown, the elastic telescopic member 11 is fixed around the outer wall of the temperature regulating member 10. It can be understood that the elastic telescopic member 11 and the temperature regulating member 10 are coaxially arranged, and the temperature regulating member 10 can be cylindrical in shape.

[0049] In one embodiment, such as Figure 4As shown, a flow channel for helium to pass through is formed between the outer wall of the elastic expansion member 11 and the inner wall of the outlet end of the helium gas guide 5. The flow channel has an annular structure. The elastic expansion member 11 is made of a material that expands and contracts with temperature, so that it deforms after absorbing the heat generated by the temperature regulating member 10, thereby adjusting the radial flow area of ​​the flow channel.

[0050] In this embodiment, the elastic expansion member 11 is coaxially attached to the outer wall of the temperature regulating member 10, forming an annular flow channel with the inner side wall of the outlet end of the helium gas guide 5. After adopting a material that expands and contracts with heat, the heating of the temperature regulating member 10 can be used as the driving source: the more the temperature regulating member 10 heats up, the greater the radial expansion of the elastic expansion member 11 absorbs heat and the smaller the flow area. Thus, when the temperature of the edge area is compensated for by high heating, the edge helium flow rate is automatically reduced to avoid heat exchange overshoot caused by "temperature increase while gas flow rate remains unchanged".

[0051] In one embodiment, such as Figure 4 As shown, the second elastic expansion member is fixed around the outer wall of the second temperature regulating member. A flow channel for helium gas to pass through is formed between the outer wall of the second elastic expansion member and the inner wall of the outlet end of the second helium gas guide 7. The second elastic expansion member is made of a material that expands and contracts with temperature, so that it deforms after absorbing the heat generated by the second temperature regulating member, thereby adjusting the radial flow area of ​​the flow channel.

[0052] In this embodiment, the second elastic expansion member is coaxially attached to the outer wall of the second temperature regulating member, forming an annular flow channel with the inner side wall of the outlet end of the second helium channel 7. After adopting a material that expands and contracts with heat, the heating of the second temperature regulating member can be used as the driving source: the more the second temperature regulating member heats up, the greater the radial expansion of the second elastic expansion member and the smaller the flow area. Thus, when the temperature of the central area is compensated for by high heating, the helium flow rate in the central area is automatically reduced, avoiding heat exchange overshoot caused by "temperature increase while gas flow remains unchanged".

[0053] In one embodiment, such as Figure 4 As shown, the electrostatic chuck also includes several connectors 13 and several connectors 2. Both connectors 13 and connectors 2 are made of elastic material, preferably high-temperature resistant silicone strips or polyimide elastic ribs. The shape of connectors 13 and connectors 2 is preferably cylindrical. The number of connectors 13 and connectors 2 can be three, four, or more.

[0054] In one embodiment, such as Figure 4 As shown, a plurality of the connectors 13 are arranged circumferentially at intervals in the outlet end of the helium gas channel 5, preferably at equal intervals; the two ends of each connector 13 are respectively fixed to the inner side wall of the outlet end of the helium gas channel 5 and the outer side wall of the elastic telescopic member 11.

[0055] The two ends of the circumferentially spaced elastic connectors 13 are respectively fixed to the inner wall of the outlet end of the helium guide 5 and the outer wall of the elastic expansion member 11. This provides radial positioning support for the elastic expansion member 11, preventing it from being eccentric or collapsing under the scouring of the helium flow. Because it is made of elastic material, it can expand and contract synchronously with the thermal expansion member 11, without restricting its radial deformation degree of freedom. This ensures that the cross-sectional adjustment of the flow channel is stable and uniform, realizing the dual function of "flexible support and follow-up expansion and contraction", and ensuring the reliability of adaptive adjustment of the helium flow in the edge area.

[0056] In one embodiment, such as Figure 4 As shown, several connectors 2 are arranged circumferentially at intervals within the outlet end of the helium gas channel 2 7, preferably at equal intervals. The two ends of each connector 2 are respectively fixed to the inner sidewall of the outlet end of the helium gas channel 2 7 and the outer sidewall of the elastic telescopic member 2. The function of the connector 2 is the same as that of connector 13, and will not be repeated here.

[0057] In one embodiment, such as Figure 4 As shown, the electrostatic chuck also includes an elastic restraint component 12 and an elastic restraint component 2; the materials of the elastic restraint component 12 and the elastic restraint component 2 are preferably highly elastic polytetrafluoroethylene or fluororubber thin bundle rings.

[0058] In one embodiment, such as Figure 4 As shown, the elastic restraint member 12 is fixed around at least part of the outer wall of the elastic telescopic member 11 so as to cause the elastic telescopic member 11 to deform uniformly under the circumferential restraint force of the elastic restraint member 12.

[0059] The elastic restraint member 12 constrains the deformation mode of the elastic expansion member 11 with a circumferential clamping force, so that when it absorbs heat from the temperature regulating member 10, it can only expand and contract uniformly in the radial direction, suppressing local bulging or elliptical distortion, thereby ensuring the consistency of the cross-sectional roundness and circumferential opening of the flow channel, and avoiding local overcooling or overheating of the edge sub-heat exchange cavity caused by the eccentric distribution of helium flow velocity.

[0060] In one embodiment, the height of the elastic restraint member 12 can be the same as or different from the height of the elastic expansion member 11. Specifically, when their heights are the same, the elastic restraint member 12 applies a uniform circumferential constraint to the entire axial length of the elastic expansion member 11, which is suitable for scenarios requiring proportional reduction in diameter throughout the entire circumference and stable cross-section of the flow channel. When the height of the elastic restraint member 12 is less than the height of the elastic expansion member 11, the middle or local sections of the elastic expansion member 11 can be constrained in a targeted manner, while the remaining free sections retain a larger deformation margin, facilitating the design of non-uniform adjustment characteristics according to actual flow field requirements. For example, the elastic restraint member 12 can be omitted in the upstream section of the elastic expansion member 11 to quickly respond to temperature changes, while the elastic restraint member 12 can be added in the downstream section to maintain shape. Both settings can utilize the circumferential preload of the elastic restraint member 12 to suppress local distortion, and can be flexibly selected according to different process gas flow rates and temperature control power, taking into account both deformation uniformity and adjustment sensitivity.

[0061] In one embodiment, such as Figure 4 As shown, the second elastic restraint member is fixed around at least a portion of the outer wall of the second elastic telescopic member to cause the second elastic telescopic member to deform uniformly under the circumferential restraint force. The second elastic restraint member and the first elastic restraint member 12 have the same function, which will not be described again here. The height of the second elastic restraint member is also consistent with the height reference direction of the first elastic restraint member 12, which will not be described again here.

[0062] In one embodiment, such as Figure 2 As shown, the helium gas channel 5 includes an edge inlet channel 51, a connecting channel 53, and several injection slots 52. The edge inlet channel 51 is connected to an external helium supply source. The several injection slots 52 are all connected to the edge inlet channel 51 through the connecting channel 53. The several injection slots 52 are arranged on the edge suction cup 32 with different radii and centered on the central axis of the suction cup. The outlet end of each injection slot 52 is connected to the edge sub-heat exchange chamber.

[0063] The helium gas channel 5 uses a tree-like structure of "main air intake, connection and distribution, and multi-radius ring-shaped injection groove 52" to evenly distribute the external helium to different radius positions of the edge suction cup 32, so that the back-blown helium in the edge sub-heat exchange cavity is evenly distributed in both the circumferential and radial directions, eliminating the pressure bias and heat exchange dead zone of single-point gas supply.

[0064] In one embodiment, the second helium channel 7 includes a central inlet channel 71, a second connecting channel 73, and a plurality of second injection slots 72. The central inlet channel 71 is connected to an external helium supply source. The plurality of second injection slots 72 are connected to the central inlet channel 71 through the second connecting channel 73. The plurality of second injection slots 72 are arranged on the central suction cup 31 with different radii centered on the central axis of the suction cup, and the outlet end of each second injection slot 72 is connected to the central sub-heat exchange chamber.

[0065] The design concept and function of the helium gas guide 7 and the helium gas guide 5 are the same, and will not be repeated here.

[0066] To address the problems existing in the prior art, embodiments of the present invention also provide a plasma processing device, such as... Figure 1 As shown, the plasma processing device includes a reaction chamber 1, a base 2, and a helium-cooled electrostatic chuck, which is disposed in the reaction chamber 1 via the base 2.

[0067] In some embodiments, the plasma processing equipment can be an etching equipment, a photoresist stripping equipment, or a deposition equipment. In the etching equipment, the plasma bombardment on the wafer surface is strong, and the thermal load difference between the central and edge regions is significant. The independent temperature control of the electrostatic chuck in this invention can effectively flatten the etching rate distribution and improve the uniformity of critical dimensions. In the photoresist stripping equipment, high-temperature ashing can easily lead to local overheating at the edges. Independent liquid cooling and helium temperature control can quickly suppress the edge temperature rise and prevent uneven photoresist residue. In the deposition equipment, the film thickness is highly sensitive to temperature. Dual-zone collaborative temperature control can stabilize the temperature within the wafer surface at the target window and reduce radial deviation of the film thickness. Therefore, this electrostatic chuck can be widely adapted to various plasma process scenarios, improving the versatility of the equipment and the process yield.

[0068] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the present invention. Furthermore, the present invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A helium-cooled electrostatic chuck, characterized in that, It includes a suction cup, an edge liquid flow channel, a helium gas guide channel one, a central liquid flow channel and a helium gas guide channel two, and the upper surface of the suction cup and the wafer it carries form a heat exchange cavity. The suction cup includes a center suction cup, an edge suction cup, and a heat insulation ring. The center suction cup and the edge suction cup correspond to the central region and the edge region of the wafer, respectively. The edge suction cup is arranged around the outside of the center suction cup, and the heat insulation ring is arranged between the center suction cup and the edge suction cup to block the heat transfer channel between the center suction cup and the edge suction cup. Both the edge liquid flow channel and the first helium gas guide channel are located inside the edge suction cup, and the outlet end of the first helium gas guide channel is connected to the heat exchange cavity to deliver helium gas into the heat exchange cavity. The heat of the edge region is conducted to the edge suction cup by the helium gas, and then the edge region is cooled by the cooling liquid in the edge liquid flow channel. Both the central liquid flow channel and the second helium gas guide channel are located inside the central suction cup. The outlet end of the second helium gas guide channel is connected to the heat exchange chamber to deliver helium gas into the heat exchange chamber. The heat of the central region is conducted to the central suction cup by the helium gas, and then the central region is cooled by the cooling liquid in the central liquid flow channel.

2. The helium-cooled electrostatic chuck according to claim 1, characterized in that, The electrostatic chuck further includes an annular extension, which extends circumferentially at the top of the heat insulation ring. The top of the annular extension extends away from the top of the heat insulation ring and is higher than the upper surface of the chuck. The annular extension divides the heat exchange cavity into a central sub-heat exchange cavity corresponding to the central region and an edge sub-heat exchange cavity corresponding to the edge region. The outlet end of the first helium gas channel is connected to the edge sub-heat exchange cavity, and the outlet end of the second helium gas channel is connected to the central sub-heat exchange cavity, so as to separate the helium gas injected into the edge sub-heat exchange cavity and the central sub-heat exchange cavity.

3. The helium-cooled electrostatic chuck according to claim 1, characterized in that, Both the central suction cup and the edge suction cup include a suction cup body, an adhesive layer, an aluminum nitride ceramic layer, and an oxide layer; The oxide layer is fixed to the top of the suction cup body and forms a sealed cavity between it and the suction cup body; The aluminum nitride ceramic layer and the adhesive layer are disposed in the sealed cavity, and the aluminum nitride ceramic layer is fixed to the top of the suction cup body by the adhesive layer; The first helium gas channel and the second helium gas channel respectively pass through the corresponding suction cup body, the adhesive layer, the aluminum nitride ceramic layer and the oxide layer.

4. The helium-cooled electrostatic chuck according to claim 3, characterized in that, The electrostatic chuck further includes an oxide ring, which comprises a central sub-ring and an edge sub-ring; The central sub-ring is coaxially disposed at the outlet end of the helium gas channel two, and the orthographic projection structure of the central sub-ring on the inner sidewall of the helium gas channel two covers the sidewall of the aluminum nitride ceramic layer. The edge sub-ring is coaxially disposed at the outlet end of the helium gas channel one, and the orthographic projection structure of the edge sub-ring on the inner sidewall of the helium gas channel one covers the sidewall of the aluminum nitride ceramic layer to prevent the aluminum nitride ceramic layer from contacting the helium gas.

5. The helium-cooled electrostatic chuck according to claim 3, characterized in that, Both the central suction cup and the edge suction cup further include at least one aluminum nitride ceramic ring. Each aluminum nitride ceramic ring is arranged around the central axis of the suction cup with different radii within the suction cup body. The top of each aluminum nitride ceramic ring is connected to the bottom of the aluminum nitride ceramic layer and extends towards the bottom of the suction cup body along the central axis, so as to conduct the heat on the aluminum nitride ceramic layer to the bottom of the suction cup body along each aluminum nitride ceramic ring.

6. The helium-cooled electrostatic chuck according to claim 2, characterized in that, The electrostatic chuck also includes a temperature regulating component one and a temperature regulating component two; The temperature regulating element is located at the outlet end of the helium gas channel and is connected to an external power supply. When powered on, it adjusts the temperature of the helium gas entering the edge sub-heat exchange cavity to keep the temperature of the edge region within a first preset temperature. The second temperature regulating element is located at the outlet end of the second helium gas channel and is connected to an external power source. When powered on, it adjusts the temperature of the helium gas entering the central sub-heat exchange cavity to keep the temperature of the central region within a second preset temperature.

7. The helium-cooled electrostatic chuck according to claim 6, characterized in that, The electrostatic chuck also includes an elastic telescopic component one and an elastic telescopic component two; The elastic expansion member is fixed around the outer wall of the temperature regulating member. A flow channel for helium to pass through is formed between the outer wall of the elastic expansion member and the inner wall of the outlet end of the helium gas guide. The elastic expansion member is made of a material that expands and contracts with temperature, so that it deforms after absorbing the heat generated by the temperature regulating member, thereby adjusting the radial flow area of ​​the flow channel. The second elastic expansion member is fixed around the outer wall of the second temperature regulating member. A flow channel for helium to pass through is formed between the outer wall of the second elastic expansion member and the inner wall of the outlet end of the second helium gas guide. The second elastic expansion member is made of a material that expands and contracts with temperature, so that it deforms after absorbing the heat generated by the second temperature regulating member, thereby adjusting the radial flow area of ​​the flow channel.

8. The helium-cooled electrostatic chuck according to claim 7, characterized in that, The electrostatic chuck also includes several connector 1 and several connector 2, both of which are made of elastic material; Several connectors are arranged circumferentially at intervals in the outlet end of the helium channel, and the two ends of each connector are respectively fixed to the inner side wall of the outlet end of the helium channel and the outer side wall of the elastic telescopic member. Several connectors are arranged circumferentially at intervals inside the outlet end of the helium channel, and the two ends of each connector are respectively fixed to the inner side wall of the outlet end of the helium channel and the outer side wall of the elastic telescopic member.

9. The helium-cooled electrostatic chuck according to claim 7, characterized in that, The electrostatic chuck also includes an elastic restraint component one and an elastic restraint component two; The elastic restraint member is fixed around at least part of the outer wall of the elastic telescopic member to make the elastic telescopic member deform uniformly under the circumferential restraint force of the elastic restraint member. The second elastic restraint member is fixed around at least part of the outer wall of the second elastic telescopic member to cause the second elastic telescopic member to deform uniformly under the circumferential restraint force of the second elastic restraint member.

10. The helium-cooled electrostatic chuck according to claim 2, characterized in that, The helium gas channel 1 includes an edge inlet channel, a connecting channel 1, and several injection slots 1. The edge inlet channel is connected to an external helium supply source. The several injection slots 1 are all connected to the edge inlet channel through the connecting channel 1. The several injection slots 1 are arranged on the edge suction cup with different radii and centered on the central axis of the suction cup. The outlet end of each injection slot 1 is connected to the edge sub-heat exchange chamber.

11. The helium-cooled electrostatic chuck according to claim 2, characterized in that, The second helium gas channel includes a central inlet channel, a second connecting channel, and several second injection slots. The central inlet channel is connected to an external helium supply source. The several second injection slots are connected to the central inlet channel through the second connecting channel. The several second injection slots are arranged on the central suction cup with different radii, centered on the central axis of the suction cup. The outlet end of each second injection slot is connected to the central sub-heat exchange chamber.

12. A plasma processing device, characterized in that, It includes a reaction chamber, a base, and a helium-cooled electrostatic chuck as described in any one of claims 1 to 11, wherein the helium-cooled electrostatic chuck is disposed in the reaction chamber via the base.

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