Electrostatic chuck with electrostatic adsorption and multi-temperature zone uniform heating and method of manufacturing the same

Abstract

The application discloses an electrostatic chuck integrating electrostatic adsorption and multi-temperature-zone uniform heating, and belongs to the technical field of semiconductor manufacturing equipment. The electrostatic chuck adopts a self-top-to-bottom stacked integrated structure, and is sequentially provided with a dielectric adsorption layer, a partition type high-voltage electrode layer, a high-voltage electrode connecting layer, a four-temperature-zone annular heating layer, a thimble hole electrode layer and a bottom insulating layer. All the layers are integrally formed through a co-firing process. The four-temperature-zone annular heating layer is added, and the specific structures of the high-voltage electrode layer and the four-temperature-zone annular heating layer are set, so that the deep integration of electrostatic adsorption and multi-temperature-zone uniform heating is realized, the interlayer thermal resistance of the split structure is eliminated, the uniformity of wafer global adsorption is greatly reduced, the wafer surface temperature difference is controlled within ±1 DEG C, the temperature response speed and the temperature control precision are improved, and the advanced semiconductor process requirements of wafers of different sizes can be met.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor fabrication accessories technology, specifically relating to an electrostatic chuck that integrates electrostatic adsorption and multi-temperature zone uniform heating, and its fabrication method. Background Technology

[0002] An electrostatic chuck, also known as an electrostatic chuck (E-Chuck), is an ultra-clean wafer carrier suitable for vacuum and plasma environments. Modern semiconductor manufacturing processes include wafer cleaning, oxidation, photolithography, etching, and deposition. Each process involves multiple steps, including etching, ion implantation, physical vapor deposition (PVD), and chemical vapor deposition (CVD). These processes all require stable wafer fixation, necessitating the use of electrostatic chucks to firmly hold the wafer in place through the attraction generated by electrostatic charge. The electrostatic chuck fixes the wafer through electrostatic adsorption, offering advantages such as uniform adsorption distribution across the wafer surface, preventing warping and deformation, and maintaining stable adsorption forces to ensure wafer processing accuracy. Secondly, wafer temperature is also a crucial factor in semiconductor processing. Even slight temperature differences can cause significant deviations during processing. Therefore, temperature homogeneity control is a critical issue in semiconductor-related processes, as uniform wafer temperature ensures the achievement of the final semiconductor processing goals. To achieve highly uniform temperature control on the wafer surface, a multi-temperature zone heating structure is employed. By independently adjusting the heating power of each zone, edge effects and process thermal disturbances are compensated for, thereby meeting the requirements of advanced processes for extremely low tolerance to temperature fluctuations. Currently, most electrostatic chucks on the market are individual electrostatic adsorption chucks with temperature control devices. However, this setup results in numerous auxiliary devices and uneven temperature distribution.

[0003] Chinese invention patent application CN121930025A discloses a processing method for an alumina electrostatic chuck. The method involves processing a high-voltage electrode groove on a substrate, assembling the entire assembly into a furnace, and then applying vacuum pressure to obtain the alumina electrostatic chuck. However, this method cannot solve the technical problem of uniform temperature control.

[0004] Chinese invention patent application CN1777987A discloses a high-performance electrostatic chuck comprising a resistive layer, microgrooves, and a dielectric layer. This multi-layered structure is used to achieve HTC uniformity and prevent gas leakage. However, this technical solution also fails to address the problem of uniform temperature control.

[0005] Therefore, there is an urgent need to develop an electrostatic chuck that can achieve both electrostatic adsorption and uniform heating in multiple temperature zones. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an electrostatic chuck that integrates stable electrostatic adsorption, a large electrostatic adsorption area, multiple temperature zones, and uniform heating.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An electrostatic chuck that integrates electrostatic adsorption and uniform heating in multiple temperature zones includes, from top to bottom, a dielectric adsorption layer, a high-voltage electrode layer, a high-voltage electrode connection layer, a ring-shaped heating four-temperature zone layer, a pinhole electrode layer, and an insulating layer.

[0008] The dielectric adsorption layer is used to adsorb and fix the wafer onto the dielectric adsorption layer by Coulomb force after a DC voltage is applied to the high voltage electrode layer.

[0009] The high-voltage electrode layer includes multiple staggered high-voltage electrode negative and positive portions. Dielectric trenches and uniformly distributed through-holes are formed on the high-voltage electrode layer. The dielectric trenches are made of an insulating material (the dielectric trenches are filled with a low-k dielectric constant insulating dielectric material, specifically silicon oxide, silicon nitride, or an alumina / silicon nitride insulating paste homologous to the surrounding ceramic substrate). The dielectric trenches electrically isolate adjacent high-voltage electrode negative or positive portions. The total area of ​​the high-voltage electrode negative portions is N. 总 and the positive electrode P of the high voltage electrode 总 , where N 总 <P 总 <1.39N 总 .

[0010] The high-voltage electrode connection layer is used to connect the negative or positive high-voltage electrode portions of different regions in the high-voltage electrode layer in series within a group, and through the conductive through holes provided inside, to uniformly guide and arrange the partitioned circuits of the upper high-voltage electrode layer and the control circuits of the lower annular heating four-temperature zone layer.

[0011] The annular heating four-temperature zone layer consists of four coaxially nested independent annular heating circuits, which are, from the inside to the outside, an inner temperature zone, a middle temperature inner zone, a middle temperature outer zone, and an outer temperature zone. Each temperature zone is independently temperature controlled (the heating power of the four temperature zones can be completely independently adjusted). The area ratio of the inner temperature zone: the middle temperature inner zone: the middle temperature outer zone: the outer temperature zone is (7.45~8.25): (9.05~9.85): (11.60~12.45): (4.0~4.8).

[0012] The problem of uniform temperature control cannot be solved simply by adding an annular heating layer. Instead, it requires the rational setting of each temperature zone and the study of the impact of adding this layer on the high-voltage electrode layer, thereby changing the specific structure of the high-voltage electrode layer to adapt to the newly added annular heating four-temperature zone layer.

[0013] The pinhole electrode layer guides all control electrodes of the high-voltage electrode layer and the annular heating four-temperature zone layer to the external interface at the bottom of the chuck.

[0014] The insulating layer is located at the bottom and has one or more layers (preferably 2 to 3 layers of the same material).

[0015] Preferably, the dielectric adsorption layer, high voltage electrode layer, high voltage electrode connection layer, annular heating four-temperature zone layer, pinhole electrode layer and insulating layer are all coaxially arranged circular layers with the same diameter.

[0016] Preferably, one or more insulating layers (preferably 2 to 3 insulating layers of the same material, as a reserved layer for subsequent grinding and polishing processes) are also provided on the upper part of the dielectric adsorption layer.

[0017] Preferably, the high-voltage electrode layer is provided with 6 to 12 fan-shaped regions, adjacent fan-shaped regions are separated by dielectric trenches, each fan-shaped region includes a high-voltage electrode negative part and a high-voltage electrode positive part, the high-voltage electrode negative part and the high-voltage electrode positive part of a single fan-shaped region are separated by dielectric trenches, and the high-voltage electrode negative part is a fan-shaped region with missing central corners, and the high-voltage electrode positive part is the remaining part of the fan-shaped region.

[0018] Preferably, the negative high-voltage electrode portion of each sector region is separated from the negative high-voltage electrode portion of the adjacent sector region by a dielectric trench, and the positive high-voltage electrode portion of each sector region is separated from the positive high-voltage electrode portion of another adjacent sector region by a dielectric trench.

[0019] Preferably, the dielectric adsorption layer is made of high-purity alumina or aluminum nitride ceramic material, with a thickness of 1~2mm, a flatness tolerance of ≤±2μm, and a dielectric strength of ≥10kV / mm.

[0020] Preferably, the high-voltage electrode layer is formed by screen printing using tungsten or molybdenum metal paste, the width of the dielectric trench is 0.5~2mm, the diameter of the through hole is 0.4~1.8mm, and the total electrode area accounts for more than 75% of the total area of ​​the high-voltage electrode layer.

[0021] Preferably, the annular heating four-temperature zone layer is formed by printing tungsten paste onto a ceramic film using a screen printing plate.

[0022] Furthermore, as a preferred design, the four temperature zones are not identical, regular circular rings. Instead, in the inner temperature zone, each ring area is divided into 2-3 arc-shaped structures, and a density-reducing region is located near the middle temperature zone within the inner temperature zone. This design further unifies the temperature of the entire electrostatic chuck, resulting in more uniform heating of the wafer during operation.

[0023] Preferably, the heating power of each temperature zone of the annular heating four-temperature zone layer is independently adjustable within the range of 0~500W (which can adapt to the temperature control requirements of wafers of different sizes such as 6-inch, 8-inch, and 12-inch), and the temperature difference across the entire wafer surface is controlled within ±1℃.

[0024] Preferably, the pin hole electrode layer is provided with an annular auxiliary electrode at the edge of each pin hole opening. The annular auxiliary electrode is electrically isolated from the high voltage electrode layer and can be individually applied with a reverse voltage to eliminate the residual wafer adsorption force around the pin hole.

[0025] Preferably, the dielectric adsorption layer has a thickness of 1~2mm, the high voltage electrode layer has a thickness of 0.2~0.8mm, the high voltage electrode connection layer has a thickness of 0.1~0.3mm, the annular heating four-temperature zone layer has a thickness of 0.2~0.8mm, the pin hole electrode layer has a thickness of 0.3~0.5mm, and the insulating layer has a thickness of 0.8~1.2mm.

[0026] A method for preparing an electrostatic chuck, wherein the electrostatic chuck is the electrostatic chuck described above, includes the following steps: S1, the dielectric adsorption layer, high voltage electrode layer, high voltage electrode connection layer, annular heating four-temperature zone layer, pin hole electrode layer and insulating layer are stacked sequentially from top to bottom, with the axial center positions of each layer overlapping and the diameters of each layer being equal, to obtain the stacked layer.

[0027] S2, the stacked layer obtained in S1 is placed into a high-pressure cavity filled with a heated and pressure-transmitting medium, and isothermal pre-compression is performed under the conditions of temperature of 60~80℃ and pressure of 20~40MPa, while removing interlayer air.

[0028] S3, the stacked layer obtained in S2 is placed in an atmosphere-protected sintering furnace, and the temperature is first increased to 450~550℃ at a rate of 1~5℃ / min, and held at this temperature for 10~15h. Then the temperature is further increased to 1500~1800℃, and high-temperature co-firing is carried out at this temperature for 20~30h, controlling the interlayer insulation resistance to be ≥10 Ω·cm. 14 Ω.

[0029] S4, through rough grinding with a feed rate of 5~10µm / cycle, corrects the flatness error of the electrostatic chuck obtained after high-temperature co-firing of S3 to ≤20µm. The rough grinding time is 20~30min.

[0030] S5, replace with a fine-grained grinding disc, adjust the feed rate to 1~3µm / time, correct the flatness error to ≤5μm, reduce the surface roughness to Ra≤1.0, and continue for 30~40min.

[0031] S6 uses a polyurethane polishing pad and nano-diamond polishing slurry, and performs non-feed optical polishing for 15~20 minutes to finally stabilize the roughness of the adsorption surface at Ra≤0.1, while the overall flatness is ≤3μm, resulting in an electrostatic chuck product that combines electrostatic adsorption and uniform heating in multiple temperature zones.

[0032] Because the layout of each layer has been improved, the parameters in the method steps need to be adjusted to adapt to the changes in the layout of each layer. Therefore, by setting the parameters of the above specific steps, the final electrostatic chuck can achieve the technical effect of electrostatic adsorption and uniform heating and temperature control in multiple temperature zones without increasing the thickness.

[0033] As a preferred option, steps S4 to S6 are performed entirely using a double-sided flat grinding machine, simultaneously processing both the upper and lower surfaces of the chuck (to avoid warping and deformation caused by single-sided processing).

[0034] Preferably, the thickness of the final electrostatic chuck is 3.5~4.5 mm.

[0035] The technical advantages of this invention are as follows: 1. This invention integrates electrostatic adsorption high-voltage electrodes and multi-temperature zone heating electrodes into a single ceramic component through a specific integrated stacking and co-firing process, which completely eliminates the interlayer air thermal resistance of the split structure, greatly improves the temperature response speed, and thus significantly improves the temperature uniformity of the wafer surface during operation.

[0036] 2. This invention, through the specific design of a four-zone independent annular heating structure with inner and outer rings, can flexibly adapt to the process requirements of wafers of different sizes. By independently adjusting the heating power of each ring zone, it can accurately compensate for edge heat loss and plasma thermal disturbance, thereby meeting the requirements of advanced processes for extremely low temperature fluctuations. By setting the areas of the three inner ring temperature zones to be basically similar, while the area of ​​the outermost ring temperature zone is basically halved, it can specifically compensate for the high heat loss at the wafer edge. Since the outer ring of the wafer is in direct contact with the vacuum environment, its heat loss rate is generally about twice that of the inner ring. This invention, through reasonable settings, reduces the area of ​​the outer ring temperature zone to a specific ratio, and can accurately match the edge heat demand through higher power density. This avoids the problem of the outer ring temperature being too low under conventional equal area layout, and can control the temperature difference across the entire wafer within ±0.5℃.

[0037] 3. This invention, by setting the high-voltage electrode layer into specific fan-shaped partitions and then rationally distributing the high-voltage positive and negative electrodes within these partitions, corresponds to four non-uniform area temperature zones, achieving coordinated control of local electric field and local temperature. Since the temperature zone area at the wafer edge is relatively small, and the electric field distribution of the fan-shaped electrodes avoids local warping caused by insufficient edge adhesion, it enables uniform wafer temperature while keeping adhesion deviation essentially within 3%, thus adapting to the high-precision process requirements of advanced manufacturing processes. Furthermore, by setting multiple temperature zones in the inner and outer rings and the fan-shaped arrangement of the high-voltage electrode layer, redundant settings in the outer ring heating circuit are reduced, lowering overall power consumption and avoiding the risk of electric field concentration breakdown caused by dense outer ring electrode arrangement, thereby improving the long-term operational stability of the chuck. Furthermore, by adopting a partitioned series design for the high-voltage electrode layer and by reasonably limiting the width and density of the dielectric trenches, the electrode coverage area exceeds 75%. Such an electrode coverage area can achieve uniform electrostatic adsorption without blind spots across the entire wafer, with virtually no deviation in adsorption force, further avoiding the occurrence of local warping problems in large-size wafers.

[0038] 4. This invention, through a rational arrangement of the negative and positive regions of the high-voltage electrode, partitioned in a fan shape, with the positive region being slightly larger but not excessively so, avoids localized electric field concentration, resulting in a smoother charge distribution on the wafer surface and preventing electric field spikes at the electrode edges from breaking down the dielectric layer. Since the charge migration loss at the positive electrode is slightly higher than that at the negative electrode during high-voltage operation, the slightly larger area can offset electrode attenuation after long-term use, thereby extending the lifespan of the chuck's high-voltage electrodes and reducing the probability of electrode aging and failure. Furthermore, the densely packed through-holes allow for rapid removal of residual gases between layers during the co-firing process of multilayer ceramics, preventing internal defects such as bubbles and delamination after sintering. This ensures seamless metallurgical bonding between layers, and the through-holes enable precise alignment, achieving vertical electrical conduction between the high-voltage electrode layer and the connecting layer below, thus replacing the defects of traditional surface wiring. Moreover, these through-holes can disperse thermal stress between different materials during sintering (releasing thermal stress), thereby preventing potential electrode layer warping and cracking, further enhancing the overall structural strength.

[0039] 5. This invention deeply integrates the traditionally separate electrode lead-out structure and ejector pin auxiliary electrode functions into a single embedded ejector pin hole electrode layer. Through a pre-set co-firing integrated wiring channel within the layer, all control lines for the high-voltage adsorption electrodes in the upper eight sector-shaped zones and the four non-uniform area annular heating electrodes in the middle layer are uniformly collected into a single integrated external interface at the bottom of the chuck. This design eliminates the complex structure of dozens of independent leads scattered within the chuck in traditional processes, further reducing the overall wiring space without increasing the overall thickness of the chuck. Simultaneously, this invention integrates annular auxiliary electrodes, completely electrically isolated from the main electrodes, at the edges of the three ejector pin holes. Without the need for an additional independent adsorption and elimination electrode layer within the chuck, a reverse compensation voltage can be applied separately during the wafer release stage, precisely eliminating localized residual static charge around the ejector pin holes. This fundamentally avoids problems such as wafer sticking, fragmentation, and positional misalignment during wafer handling.

[0040] 6. This invention, by setting a specific preparation method based on a multi-layered structure, and through parameter adaptation of full-layer coaxial equal-diameter stacking and isostatic pressing pre-compression, integrates three functional electrodes—electrostatic adsorption electrode, four-temperature zone heating electrode, and pinhole auxiliary electrode—without increasing the overall thickness of the chuck, thus solving the defects of traditional split chucks such as large thickness and high thermal resistance. Furthermore, this invention matches the thermal expansion differences of the four non-uniform area temperature zones by co-firing the temperature zones with unequal areas. The gradient heating rate of 1~5℃ / min and segmented heat preservation settings avoid deformation misalignment that may occur during sintering of different areas in the heating circuit, thereby ensuring a small deviation in heating resistance among the four different temperature zones. Moreover, by setting a high-temperature co-firing temperature of 1500~1800℃, the diffusion and penetration of electrode elements into the insulation trenches can be prevented. Furthermore, the parameter settings of three-stage double-sided synchronous grinding and polishing avoid problems such as stress unevenness and warping caused by unilateral processing, thus achieving technical effects such as Ra≤0.1 on the adsorption surface. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the exploded structure of the electrostatic chuck of the present invention, which integrates electrostatic adsorption and uniform heating in multiple temperature zones.

[0043] Figure 2 This is a schematic diagram of the high-voltage electrode layer of the present invention.

[0044] Figure 3 This is a schematic diagram of the annular heating four-temperature zone layer of the present invention.

[0045] Figure 4 This is a schematic diagram of the area of ​​the annular heating four-temperature zone layer of the present invention.

[0046] Figure 5 This is a schematic diagram of the electrostatic chuck obtained after sintering and polishing according to the present invention.

[0047] Wherein: 001 - dielectric adsorption layer; 002-High voltage electrode layer, 201-High voltage electrode negative part, 202-High voltage electrode positive part, 221-Central angle, 203-Dielectric trench, 204-Through hole, 205-Electrode layer axis; 003 - High-voltage electrode connection layer; 004 - Annular heating four-temperature zone layer, 401 - Inner temperature zone, 402 - Medium temperature inner zone, 403 - Medium temperature outer zone, 404 - Outer temperature zone; 005 - Pinhole electrode layer; 006 - Insulation layer; R1 - radius of the inner temperature zone, R2 - radius of the intermediate temperature inner zone, R3 - radius of the intermediate temperature outer zone, R4 - radius of the outer temperature zone. Detailed Implementation

[0048] The process technology solution of the present invention will be further described below with reference to embodiments and accompanying drawings. Unless otherwise specified, each feature is merely one example of a series of equivalent or similar features. These embodiments are merely for the purpose of aiding understanding the present invention and should not be considered as specific limitations thereof.

[0049] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0050] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0051] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0052] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0053] Example 1

[0054] like Figure 1 As shown, the electrostatic chuck of this embodiment, which integrates electrostatic adsorption and multi-temperature zone uniform heating, includes a dielectric adsorption layer, a high-voltage electrode layer, a high-voltage electrode connection layer, a ring-shaped heating four-temperature zone layer, a pin hole electrode layer, and an insulating layer stacked sequentially from top to bottom.

[0055] The dielectric adsorption layer is a conventional dielectric adsorption layer. When a DC voltage is applied to the electrode layer, the dielectric adsorption layer becomes polarized, and a charge with the opposite polarity to that of the wafer is generated on the surface. The wafer is then adsorbed and fixed by Coulomb force.

[0056] like Figure 2 As shown, the high-voltage electrode layer in this embodiment includes eight high-voltage negative electrode portions and eight high-voltage positive electrode portions arranged in an alternating pattern, and as... Figure 2 As shown, dielectric trenches and uniformly distributed through holes are provided on the high-voltage electrode layer. Figure 203 shows the dielectric trenches, which are constructed in a fan shape, forming the electrode layer axis 205 at the center. The dielectric trenches are made of insulating material, electrically isolating adjacent negative or positive portions of the high-voltage electrodes. In this embodiment, the total area N of the negative portion of the high-voltage electrode is... 总 The area is 25229.5 square millimeters and the positive electrode portion P of the high-voltage electrode. 总 The area is 25283.3 square millimeters (because the high-voltage electrode layer also includes dielectric trenches and vias, the area of ​​these two parts is smaller than the overall area of ​​the high-voltage electrode layer), satisfying N. 总 <P 总<1.39N 总 Requirements.

[0057] like Figure 2 As shown, the high-voltage electrode layer has eight sector-shaped regions, with adjacent sector-shaped regions separated by dielectric trenches 203. Each sector-shaped region includes a high-voltage electrode negative electrode portion 201 and a high-voltage electrode positive electrode portion 202. The high-voltage electrode negative electrode portion and the high-voltage electrode positive electrode portion of a single sector-shaped region are separated by dielectric trenches, and the high-voltage electrode negative electrode portion is a sector with a missing central corner, while the high-voltage electrode positive electrode portion is the remaining section of the sector. Figure 2 As shown, the negative electrode portion of the high-voltage electrode does not include the central angle portion, so the area of ​​the positive electrode portion of the high-voltage electrode includes its own central angle and the central angle below the negative electrode portion of the high-voltage electrode, thereby achieving the concentration of the negative electrode portion of the high-voltage electrode at the opposite edge of the disk.

[0058] like Figure 2 As shown, the negative electrode portion of the high voltage electrode in each of the sector regions is separated from the negative electrode portion of the high voltage electrode in the adjacent sector regions by a dielectric trench, and the positive electrode portion of the high voltage electrode in each of the sector regions is separated from the positive electrode portion of the high voltage electrode in another adjacent sector region by a dielectric trench.

[0059] like Figure 1 As shown, the high-voltage electrode connection layer 003 is used to connect the negative or positive high-voltage electrode portions of different regions in the high-voltage electrode layer in series within a group, and through the conductive through holes provided inside, to uniformly guide and arrange the partitioned circuits of the upper high-voltage electrode layer and the control circuits of the lower annular heating four-temperature zone layer.

[0060] The entire high-voltage electrode layer is divided into 16 independent zones by internal wiring. Eight zones are grouped together and connected in series within each group to ensure that the electric field strength of each sub-region is uniform.

[0061] like Figure 3 and Figure 4 As shown, the annular heating four-temperature zone layer consists of four coaxially nested independent annular heating circuits, which, from the inside out, are the inner temperature zone, the middle temperature inner zone, the middle temperature outer zone, and the outer temperature zone. Each temperature zone is independently temperature-controlled. This heating layer consists of four coaxially nested independent annular heating circuits, corresponding to the inner temperature zone at the center, the middle temperature inner zone of the inner ring, the middle temperature outer zone of the middle ring, and the outer temperature zone of the outer ring, respectively. The heating circuits of the four temperature zones are completely independent and can be connected to an external temperature control power supply to achieve individual adjustment of the heating power. Figure 4 We can determine that their respective radii are R1 = 70.65 mm, R2 = 105 mm, R3 = 136.7 mm, and R4 = 146.7 mm. Therefore, the area ratios of the inner temperature zone: middle temperature zone: middle temperature zone: outer temperature zone are 15689.1 mm².2 18940.0 mm 2 24047.3 mm 2 and 8890.0 mm 2 Therefore, the area ratio is approximately 7.85:9.45:12.03:4.45.

[0062] And further such as Figure 3 and Figure 4 As can be seen, the annular structures of the four temperature zones are not identical regular circles. Instead, in the inner temperature zone, each annular region is divided into 2-3 arc-shaped structures, and a density-reducing area is located near the middle temperature zone within the inner temperature zone. This design further unifies the temperature of the entire electrostatic chuck, resulting in more uniform heating of the wafer during operation.

[0063] The pinhole electrode layer guides all control electrodes of the high-voltage electrode layer and the annular heating four-temperature zone layer to the external interface at the bottom of the chuck.

[0064] In this embodiment, the insulating layer is located at the bottom, and the alumina insulating layer consists of four layers.

[0065] like Figure 1 As shown, the dielectric adsorption layer, high voltage electrode layer, high voltage electrode connection layer, annular heating four-temperature zone layer, pin hole electrode layer and insulating layer are all coaxially arranged circular layers with the same diameter.

[0066] Furthermore, in this embodiment, a three-layer insulating layer (not shown in the figure) is also provided on the upper part of the dielectric adsorption layer as a reserved layer for subsequent grinding and polishing processes. The final thickness of the dielectric adsorption layer can be precisely controlled by grinding during subsequent processing.

[0067] The dielectric adsorption layer described in this embodiment is made of high-purity alumina with a thickness of 1.5 mm, a flatness tolerance of ≤ ±2 μm, and a dielectric strength of ≥ 10 kV / mm. The high-voltage electrode layer in this embodiment is formed using tungsten metal paste through a screen printing process. The width of the dielectric trench is 1.0 mm, the diameter of the through-hole is 0.9 mm, and the total electrode area accounts for approximately 77% of the total area of ​​the high-voltage electrode layer, achieving uniform electric field coverage across the entire wafer. In this embodiment, other layers may be configured as follows: a high-voltage electrode layer with a thickness of 0.5 mm, a high-voltage electrode connection layer with a thickness of 0.2 mm, a ring-shaped heating four-temperature zone layer with a thickness of 0.5 mm, a pin hole electrode layer with a thickness of 0.4 mm, and an insulating layer with a thickness of 1 mm.

[0068] In this embodiment, the pin hole electrode layer is provided with an annular auxiliary electrode at the edge of each pin hole opening. The pin hole electrode layer can guide the eight partition electrodes of the high voltage electrode layer and the four heating circuit electrodes of the annular heating four temperature zone to the external aviation plug interface at the bottom of the chuck. At the same time, independent annular auxiliary electrodes are provided at the edges of the openings of the three pin holes. The auxiliary electrodes are electrically isolated from the main high voltage electrodes and can be individually applied with reverse DC voltage. During the wafer release stage, the residual static charge around the pin holes is quickly eliminated, and the problem of die sticking fragments is completely avoided.

[0069] The electrostatic chuck in this embodiment integrates electrostatic adsorption and multi-temperature zone heating functions, eliminating the need for additional external temperature control devices. Users only need to connect a single unified water, electricity, and gas interface to put it into use on-site, which greatly reduces the complexity of system integration. At the same time, the adsorption uniformity and temperature control accuracy meet the standards for use in advanced processes.

[0070] Example 2

[0071] This embodiment illustrates the preparation method of the electrostatic chuck of Example 1, including the following steps: S1, the dielectric adsorption layer, high voltage electrode layer, high voltage electrode connection layer, annular heating four-temperature zone layer, pin hole electrode layer and insulating layer are stacked sequentially from top to bottom, with the axial center positions of each layer overlapping and the diameters of each layer being equal, to obtain the stacked layer.

[0072] S2, the stacked layer obtained in S1 is placed into a high-pressure cavity filled with a heated and pressure-transmitting medium, and isothermal pre-compression is performed at a temperature of 70℃ and a pressure of 30MPa, while removing interlayer air.

[0073] S3, the stacked layer obtained in S2 is placed in an atmosphere-protected sintering furnace, first heated to 500℃ at a rate of 3℃ / min, held at this temperature for 12 hours, then further heated to 1700℃, and co-fired at this temperature for 26 hours, controlling the interlayer insulation resistance to be ≥10 Ω·cm. 14 Ω; S4, through rough grinding with a feed rate of 6µm / cycle, corrects the flatness error of the electrostatic chuck obtained after high-temperature co-firing of S3 to ≤20µm, and the rough grinding time is 28min; S5, replace with fine-grained grinding disc, adjust feed rate to 2µm / cycle, correct flatness error to ≤5μm, reduce surface roughness to Ra≤1.0, continue for 35min; S6, using a polyurethane polishing pad and nano-diamond polishing slurry, performs non-feed polishing for 18 minutes, ultimately stabilizing the surface roughness of the adsorption surface to Ra≤0.1, while maintaining an overall flatness ≤3μm. Steps S4 to S6 utilize a double-sided grinding machine throughout, simultaneously processing both the upper and lower surfaces of the electrostatic chuck. This yields an electrostatic chuck product that integrates electrostatic adsorption and uniform heating across multiple temperature zones. The resulting product is as follows: Figure 5 As shown, this is a multi-layered, compacted, stacked disk structure.

[0074] Comparative Example 1 This comparative example is used to illustrate a comparative test that does not employ the high-voltage electrode layer arrangement of Example 1. The difference from Example 1 is that the positions and shapes of the negative and positive portions of the high-voltage electrode are interchanged with those in Example 1 (i.e., the arrangement of the eight sector regions is different). Figure 2 In Example 1, 201 is the positive electrode portion of the high-voltage electrode, and 202 is the negative electrode portion of the high-voltage electrode. The other configurations are exactly the same as in Example 1, and the preparation method of Example 2 is also used. The electrostatic chuck was tested and found to have poor wafer adhesion. Furthermore, the maximum temperature difference across the entire wafer was found to be 4°C, while the maximum temperature difference across the entire wafer in Example 1 was ±0.5°C.

[0075] This is because after the swap, concentrating only a relatively small area of ​​high-voltage positive electrode at the edge (without the center) cannot provide sufficient positive charge injection to the wafer's central region. This directly leads to insufficient electric field strength in most areas of the inner wafer, resulting in a significant increase in overall adhesion deviation. This manifests as localized warping and poor adhesion at the wafer's center. Furthermore, since the small positive electrode area is mainly concentrated on the periphery of the chuck (without the central corner), the current density per unit area increases. This arrangement easily creates electric field spikes at the electrode edges, potentially causing dielectric layer breakdown. Because the charge migration loss at the positive electrode is already much higher than at the negative electrode, placing all the small positive electrodes on the periphery of the chuck, where heat dissipation is poor and thermal disturbances are strong, will significantly increase the local operating temperature of the positive electrode, doubling the metal ion migration rate and thus drastically affecting the lifespan of the electrostatic chuck.

[0076] More importantly, the inner ring of this comparative example lacks sufficient positive charge support, and the annular heating four-temperature zone layer is exactly the same as that in Example 1. This results in insufficient adsorption stability of the inner ring of the wafer, which cannot cooperate with the three equal-area temperature zones of the inner ring to achieve uniform heat conduction. Ultimately, this leads to a temperature difference of more than 3°C across the entire wafer, which cannot meet the temperature control requirements of advanced processes.

[0077] This further illustrates that the arrangement of the high-voltage electrode layer and the annular heating four-temperature zone layer in this invention do not each play their own independent role, but rather have a close synergistic effect.

[0078] Comparative Example 2 This comparative example illustrates a test conducted without the annular heating four-temperature zone layer setup of Example 1. The difference from Example 1 is that instead of four annular temperature zones, three annular temperature zones of substantially equal area are used. All other settings are identical to Example 1, and the preparation method of Example 2 is also employed. Testing of the resulting electrostatic chuck revealed that the maximum global temperature difference over the wafer was ±3.5℃, while the maximum global temperature difference in Example 1 was ±0.5℃.

[0079] This is because the outermost temperature zone of the three equal-area temperature zones has the same area as the inner zone. Such a relatively large area cannot accurately compensate for the high heat loss at the edge of the wafer through high power density. The heat loss at the outermost zone cannot be accurately offset, and a significant temperature drop will appear in the wafer edge area, resulting in the above-mentioned ±3.5℃ temperature difference across the entire region.

[0080] Furthermore, the original eight independent sub-circuits of the partitioned sector high-voltage electrode, which were originally in one-to-one correspondence with the four non-uniform area temperature zones in Example 1 and could achieve coordinated control, have been changed to three uniform area temperature zones. This has resulted in misalignment of the electrode partitions and temperature zone boundaries, leading to mismatches of multiple electrodes corresponding to single temperature zones in local areas. Consequently, it is impossible to achieve precise coordinated control of local adsorption force and local temperature, resulting in uneven adsorption defects in the wafer and exacerbating the superposition defects of temperature deviations.

[0081] Furthermore, since the four annular heating circuits with unequal areas set in Embodiment 1 of the present invention are adapted to the thermal expansion coefficient of the specific material, this comparative example is changed to three annular heating circuits with equal areas, which increases the total area of ​​the metal electrode. This reduces the matching degree of thermal expansion coefficient with the original high-voltage electrode layer. During the preparation process, uneven interlayer stress is likely to occur during high-temperature co-firing, which in turn leads to the risk of electrode deformation misalignment and delamination cracking. In addition, the stability of interlayer insulation resistance will also decrease, resulting in a significant decrease in yield.

[0082] This further demonstrates that the various layers of the present invention, as well as the specific arrangement and preparation method of each layer, are closely coordinated and synergistic. Changing one or more of them will cause the product to fail to achieve its preset technical effect. Moreover, changing one of them does not only cause the function of that item to fail, but also affects other functions and technical effects. This further proves that the above-mentioned layer arrangement and preparation method are closely coordinated and synergistic, and cannot be separated to judge their independent technical effects.

[0083] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. An electrostatic chuck integrating electrostatic adsorption and multi-temperature zone uniform heating, characterized in that, It includes, from top to bottom, a dielectric adsorption layer, a high-voltage electrode layer, a high-voltage electrode connection layer, a ring-shaped heating four-temperature zone layer, a pinhole electrode layer, and an insulating layer. The dielectric adsorption layer is used to adsorb and fix the wafer onto the dielectric adsorption layer by Coulomb force after a DC voltage is applied to the high voltage electrode layer. The high-voltage electrode layer includes multiple staggered high-voltage electrode negative and positive portions. Dielectric trenches and uniformly distributed through-holes are formed on the high-voltage electrode layer. The dielectric trenches are made of insulating material and electrically isolate adjacent high-voltage electrode negative or positive portions. The total area of ​​the high-voltage electrode negative portions is N. 总 and the positive electrode P of the high voltage electrode 总 , where N 总 <P 总 <1.39N 总 ; The high-voltage electrode connection layer is used to connect the negative or positive high-voltage electrode portions of different regions in the high-voltage electrode layer in series within a group, and through the conductive through holes provided inside, to uniformly guide and arrange the partitioned circuits of the upper high-voltage electrode layer and the control circuits of the lower annular heating four-temperature zone layer. The annular heating four-temperature zone layer consists of four coaxially nested independent annular heating circuits, which are, from the inside to the outside, an inner temperature zone, a middle temperature inner zone, a middle temperature outer zone, and an outer temperature zone. Each temperature zone is independently temperature controlled, and the area ratio of the inner temperature zone: middle temperature inner zone: middle temperature outer zone: outer temperature zone is (7.45~8.25): (9.05~9.85): (11.60~12.45): (4.0~4.8). The pinhole electrode layer guides all control electrodes of the high-voltage electrode layer and the annular heating four-temperature zone layer to the external interface at the bottom of the chuck. The insulating layer is disposed at the bottom and may consist of one or more layers.

2. The electrostatic chuck according to claim 1, characterized in that, The dielectric adsorption layer, high voltage electrode layer, high voltage electrode connection layer, annular heating four-temperature zone layer, pinhole electrode layer, and insulating layer are all coaxially arranged circular layers with the same diameter.

3. The electrostatic chuck according to claim 1, characterized in that, One or more insulating layers are also provided on the upper part of the dielectric adsorption layer.

4. The electrostatic chuck according to claim 1, characterized in that, The high-voltage electrode layer is provided with 6 to 12 sector-shaped regions. Adjacent sector-shaped regions are separated by dielectric trenches. Each sector-shaped region includes a high-voltage electrode negative part and a high-voltage electrode positive part. The high-voltage electrode negative part and the high-voltage electrode positive part of a single sector-shaped region are separated by dielectric trenches. The high-voltage electrode negative part is a sector with a missing central corner, and the high-voltage electrode positive part is the remaining section of the sector.

5. The electrostatic chuck according to claim 4, characterized in that, The negative high-voltage electrode portion of each of the aforementioned sector regions is separated from the negative high-voltage electrode portion of the adjacent sector region by a dielectric trench, and the positive high-voltage electrode portion of each of the aforementioned sector regions is separated from the positive high-voltage electrode portion of another adjacent sector region by a dielectric trench.

6. The electrostatic chuck according to claim 1 or 2, characterized in that, The dielectric adsorption layer is made of high-purity alumina or aluminum nitride ceramic material, with a thickness of 1~2mm, a flatness tolerance of ≤±2μm, and a dielectric strength of ≥10kV / mm.

7. The electrostatic chuck according to claim 1 or 4, characterized in that, The high-voltage electrode layer is formed by screen printing using tungsten or molybdenum metal paste. The width of the dielectric trench is 0.5~2mm, the diameter of the through hole is 0.4~1.8mm, and the total area of ​​the electrode accounts for more than 75% of the total area of ​​the high-voltage electrode layer.

8. The electrostatic chuck according to claim 1 or 2, characterized in that, The heating power of each zone of the annular heating four-temperature zone layer is independently adjustable within the range of 0~500W, and the temperature difference across the entire wafer surface is controlled within ±1℃. The pin hole electrode layer has an annular auxiliary electrode at the edge of each pin hole opening. The annular auxiliary electrode is electrically isolated from the high voltage electrode layer and can be individually applied with a reverse voltage to eliminate the residual wafer adsorption force around the pin hole.

9. A method for preparing an electrostatic chuck, characterized in that, The electrostatic chuck is the electrostatic chuck according to any one of claims 1 to 8, comprising the following steps: S1, the dielectric adsorption layer, high voltage electrode layer, high voltage electrode connection layer, annular heating four-temperature zone layer, pin hole electrode layer and insulating layer are stacked sequentially from top to bottom, with the axial center positions of each layer overlapping and the diameters of each layer being equal, to obtain the stacked layer; S2, the stacked layer obtained in S1 is placed into a high-pressure cavity filled with a heated and pressure-transmitting medium, and isothermal pre-compression is performed under the conditions of 60~80℃ and 20~40MPa, while removing interlayer air. S3, the stacked layer obtained in S2 is placed in an atmosphere-protected sintering furnace, and the temperature is first increased to 450~550℃ at a rate of 1~5℃ / min, and held at this temperature for 10~15h. Then the temperature is further increased to 1500~1800℃, and high-temperature co-firing is carried out at this temperature for 20~30h, controlling the interlayer insulation resistance to be ≥10 Ω·cm. 14 Ω; S4, through rough grinding with a feed rate of 5~10µm / cycle, corrects the flatness error of the electrostatic chuck obtained after high-temperature co-firing of S3 to ≤20µm, and the rough grinding time is 20~30min; S5, replace with fine-grained grinding disc, adjust the feed rate to 1~3µm / time, correct the flatness error to ≤5μm, reduce the surface roughness to Ra≤1.0, and continue for 30~40min; S6 uses a polyurethane polishing pad and nano-diamond polishing slurry, and performs non-feed optical polishing for 15~20 minutes to finally stabilize the roughness of the adsorption surface at Ra≤0.1, while the overall flatness is ≤3μm, resulting in an electrostatic chuck product that combines electrostatic adsorption and uniform heating in multiple temperature zones.

10. The preparation method according to claim 9, characterized in that, Steps S4 to S6 are performed entirely using a double-sided flat grinding machine, simultaneously processing both the upper and lower surfaces of the electrostatic chuck.

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