Method for electrostatic chuck ceramic surface treatment

Abstract

The present methods and apparatus reduce chucking anomalies in an electrostatic chuck by ensuring proper planarization of the ceramic surface of the electrostatic chuck. In some embodiments, a method for planarizing an upper ceramic surface of an electrostatic chuck assembly includes placing the electrostatic chuck assembly in a first planarization apparatus, modifying the upper ceramic surface of the electrostatic chuck assembly, and performing a S a The parameter of is less than about 0.1 microns, and S dr The parameter of is less than about 2.5 percent, and S z The parameters are approximately 10mm above the upper ceramic surface 2 and ceasing to modify the upper ceramic surface of the electrostatic chuck assembly when a pit porosity depth parameter is less than about 10 microns for any given area, or greater than 1 micron, is less than about 0.1 percent of the area of ​​the upper ceramic surface.

Description

[Technical field]

[0001]

[0001] Embodiments of the present principles relate generally to semiconductor processing of semiconductor substrates. [Background technology]

[0002] Electrostatic chucks (ESCs) are used to hold semiconductor wafers for processing in a processing chamber. Wafer movement during processing or incorrect positioning of the wafer before processing can result in contamination and defects on the wafer, and can significantly degrade the performance of structures formed on the wafer. As the ESC ages, the static binding force for holding the wafer to the ESC can become irregular. It has been observed by the inventors that non-uniform binding forces often cause improper functioning of the ESC, which can lead to misaligned clamping of the wafer and even erroneous binding forces that generate contaminants due to the static clamping forces remaining when the wafer is lifted off the surface of the ESC.

[0003] Accordingly, the present inventors have provided an improved apparatus and process for producing higher performance electrostatic chucks. Summary of the Invention

[0004]

[0004] Provided herein are methods and apparatus for enhancing the performance of electrostatic chuck ceramic surfaces.

[0005] In some embodiments, a method for planarizing an upper ceramic surface of an electrostatic chuck assembly includes placing the electrostatic chuck assembly in a first planarization apparatus, modifying the upper ceramic surface of the electrostatic chuck assembly with the first planarization apparatus, and determining an arithmetic mean height (S) of the upper ceramic surface. a ) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S dr ) parameter is less than about 2.5 percent, and the maximum height of the upper ceramic surface (S z) parameters are approximately 10mm above the top ceramic surface 2 and ceasing to modify the upper ceramic surface of the electrostatic chuck assembly when a pit porosity depth parameter of less than about 10 microns for any given area of ​​the upper ceramic surface or greater than 1 micron on the upper ceramic surface is less than about 0.1 percent of the area of ​​the upper ceramic surface.

[0006] In some embodiments, the method further comprises the steps of: a ) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S dr and stopping the modification of an upper ceramic surface of an electrostatic chuck assembly when an arithmetic mean height (S) of the upper contact element surface is less than about 2.5 percent, wherein a first planarization apparatus includes a bead blasting apparatus, a polishing apparatus, a lapping apparatus, a grinding apparatus, or a chemical mechanical planarization (CMP) apparatus, and the upper ceramic surface has a plurality of contact elements disposed thereon, the plurality of contact elements having a height between about 2 microns and about 20 microns, and the plurality of contact elements are made of a diamond like coating (DLC) material; modifying the upper contact element surface of each of the plurality of contact elements with a second planarization apparatus; and determining whether an arithmetic mean height (S) of the upper contact element surface is less than about 2.5 percent. a ) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S dr ) parameter is less than about 2.5 percent, and the maximum height of the upper contact element surface (S z) is less than about 10 microns or a parameter of pit porosity depth greater than 1 micron on the upper contact element surface is less than about 0.1 percent of an area of ​​the upper contact element surface, wherein the second planarization device comprises a bead blasting device, a polishing device, a lapping device, a grinding device, or a chemical mechanical planarization (CMP) device; and stopping the modification of the upper contact element surface of the electrostatic chuck assembly when an arithmetic mean height (S) of the upper ceramic surface is less than about 10 microns or a parameter of pit porosity depth greater than 1 micron on the upper contact element surface is less than about 0.1 percent of an area of ​​the upper contact element surface. a ) parameter, the interfacial development area ratio of the upper ceramic surface (S dr ) parameters, the upper ceramic surface of about 10mm 2 The maximum height of any given area of ​​(S z and determining an end point for stopping modifying the upper ceramic surface using data from the in situ surface metrology device to determine at least one of a parameter of surface roughness, ...

[0007] In some embodiments, an apparatus for supporting a wafer on an upper surface of an electrostatic chuck includes a plurality of contact elements deposited on the upper surface of the electrostatic chuck, wherein each of the plurality of contact elements has an upper contact element surface, the upper contact element surface having an arithmetic mean height (S a ) parameter, and the interface development area ratio (S dr ) parameter, the maximum height of the upper contact element surface (S z) or a pit porosity depth parameter of greater than 1 micron that is less than about 0.1 percent of the area of ​​the upper contact element surface.

[0008] In some embodiments, the apparatus includes a surface morphology having an arithmetic mean height (S a ) parameter, and the interface development area ratio (S dr ), each of the plurality of contact elements having a height between about 2 microns and about 20 microns, and / or each of the plurality of contact elements being made of a diamond-like coating (DLC) material.

[0009] In some embodiments, a non-transitory computer readable medium having stored thereon instructions that, when executed, cause a method to be performed for planarizing an upper ceramic surface of an electrostatic chuck assembly, the method including placing the electrostatic chuck assembly in a first planarization apparatus, modifying the upper ceramic surface of the electrostatic chuck assembly using the first planarization apparatus, and determining an arithmetic mean height (S) of the upper ceramic surface. a ) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S dr ) parameter is less than about 2.5 percent, and the maximum height (Sz) parameter of the upper ceramic surface is less than about 10 mm above the upper ceramic surface 2 and ceasing to modify the upper ceramic surface of the electrostatic chuck assembly when a pit porosity depth parameter of less than about 10 microns for any given area of ​​the upper ceramic surface or greater than 1 micron on the upper ceramic surface is less than about 0.1 percent of the area of ​​the upper ceramic surface.

[0010] In some embodiments, the method of the non-transitory computer readable medium includes measuring the arithmetic mean height (S a ) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S dr) is less than about 2.5 percent; modifying the upper ceramic surface of the electrostatic chuck assembly using a first planarization apparatus, including a bead blasting apparatus, a polishing apparatus, a lapping apparatus, a grinding apparatus, or a chemical mechanical planarization (CMP) apparatus; and stopping the modification of the upper ceramic surface of the electrostatic chuck assembly when a parameter of an arithmetic mean height (S a ) parameter, the interfacial development area ratio of the upper ceramic surface (S dr ) parameters, the upper ceramic surface of about 10mm 2 The maximum height of the upper ceramic surface (S) is less than about 10 microns for any given area of z determining an endpoint for stopping the modification using data from the in situ metrology device to determine at least one of a parameter of a surface roughness (S ) or a parameter of a pit porosity depth of the upper ceramic surface, the upper ceramic surface having a plurality of contact elements disposed thereon, the plurality of contact elements having a height between about 2 microns and about 20 microns; modifying the upper contact element surface of each of the plurality of contact elements using a second planarization device; determining an endpoint for stopping the modification using data from the in situ metrology device to determine at least one of a parameter of a surface roughness (S ) or a parameter of a pit porosity depth of the upper ceramic surface; a ) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S dr ) parameter is less than about 2.5 percent, and the maximum height of the upper contact element surface (S z ) is less than about 10 microns, or a parameter of pit porosity depth greater than 1 micron on the upper contact element surface is less than about 0.1 percent of the area of ​​the upper contact element surface, and / or stopping the modification of the upper contact element surface of the electrostatic chuck assembly when the arithmetic mean height (S a ) parameter, the interfacial development area ratio of the upper contact element surface (S dr ) parameter, the maximum height of the upper contact element surface (S z) or a pit porosity depth parameter of the upper contact element surface, determining an endpoint for stopping the modification.

[0011]

[0011] Other and further embodiments are disclosed below.

[0012]

[0012] The embodiments of the present principles, briefly summarized above and described in detail below, can be understood by reference to exemplary embodiments of the present principles as illustrated in the accompanying drawings. Since the present principles are, however, susceptible of other equally effective embodiments, the accompanying drawings illustrate only typical embodiments of the present principles and therefore should not be considered as limiting in scope. [Brief description of the drawings]

[0013] [Figure 1] A method for planarizing a top ceramic surface or upper face of a contact element of an electrostatic chuck assembly, in accordance with some embodiments of the present principles. [Diagram 2]

[0014] 1 shows a cross-sectional view of an electrostatic chuck and chucking force in accordance with some embodiments of the present principles. [Diagram 3]

[0015] 1 illustrates a cross-sectional view of a portion of an electrostatic chuck with damaged ceramic and contact element surfaces, in accordance with some embodiments of the present principles; [Figure 4]

[0016] 1 illustrates three-dimensional morphology of a surface and associated parameters, according to some embodiments of the present principles; [Diagram 5]

[0017] 1 illustrates three-dimensional morphology of a surface and associated parameters, according to some embodiments of the present principles; [Figure 6]

[0018] 1 illustrates an electrostatic chuck assembly having contact elements, in accordance with certain embodiments of the present principles; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014]

[0019] To facilitate understanding, the same reference numbers have been used, where possible, to designate identical elements that are common to multiple figures. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0015]

[0020] The present method and apparatus provide an improved electrostatic chuck (ESC) ceramic surface and / or wafer pad support surface. The improvement can reduce sheet resistance non-uniformity and / or wafer positioning errors and improve the chucking performance of ESCs operating on the Johnsen-Rahbek (JR) principle. The surface morphology of the ceramic and pad surfaces is modified to provide specific properties that enhance the performance of the ESC and ensure stable and reliable operation of the ESC. The inventors have discovered that certain quantitative surface morphology characteristics result in efficient and reliable charge separation and uniformity to ensure proper chucking and dechucking of the wafer on the ESC.

[0016]

[0021] Many of the current ESCs or substrate holders, especially those operating on the JR principle, fail or become ineffective prematurely with use or due to poor manufacturing tolerances. Current typical theories do not explain why new or used ESCs fail due to loss of backside cooling gas pressure, poor wafer process uniformity, or wafer slippage due to non-uniform or unreliable chucking forces. However, the inventors have discovered that the failure mechanism is due to changes in the surface roughness or morphology of the ceramic surface of the ESC. Furthermore, the inventors have discovered that changes in the surface morphology of the ESC during wafer processing, such as pits becoming deeper or wider, impair the functionality of the contact elements or wafer support pads. The contact elements allow for uniform charge separation between the wafer backside and the top ceramic surface of the ESC, which is essential for reliable and uniform chucking. The contact elements also help maintain a uniform separation between the wafer backside and the upper ceramic surface of the ESC to allow for a critical flow and uniform pressure of the backside cooling gas, such as, for example, but not limited to, helium gas or argon gas. The uniform separation provided by the contact elements accommodates a mean free path of the backside gas within the range of 2-8 microns when operating at a pressure of 5-20 Torr. The height of the contact elements is then set to a height of 2-20 microns to ensure sufficient and uniform heat transfer through the backside gas. The present principles provide surface morphology parameters for ceramic surfaces and / or contact elements, such as aluminum nitride ESCs used in high temperature metal deposition product processing, to ensure high chucking performance of the ESC.

[0017]

[0022] ESCs operating on the JR principle work by applying a voltage to an electrode embedded in the ceramic surface (typically 1 mm below the ceramic surface). The electric field from the electrode creates a charge separation between the top surface of the ceramic and the bottom or backside of the wafer. For example, applying a positive voltage to the electrode attracts electrons to the ceramic surface, leaving a positive charge on the backside of the wafer. The attraction between the separated opposite charges provides the static chucking force of the ESC. The inventors have discovered that if the ceramic surface becomes too rough, too pitted, or too porous, it will inhibit the uniform flow of charge necessary for the ceramic surface to form a uniform charge separation. Furthermore, the inventors have found that non-uniform charge separation can lead to process non-uniformity = (R s They found that this caused typical failure modes seen with JR ESCs, including: NU%), chucking or dechucking issues, loss of backside cooling gas pressure, and / or wafer slippage (local center find or LCF error).

[0018]

[0023] This principle can be used to quantify the morphology of ceramic surfaces and surfaces of contact elements, and the arithmetic mean height (S a ), the developed surface area ratio of the interface (S dr ), maximum height (S z The present invention provides specific limits on surface morphology parameters, including the surface roughness, surface area, surface area ratio, and pit porosity area ratio to surface area ratio, to ensure reliable and stable chucking of the substrate or wafer. The inventors have discovered that typical metrology techniques used to measure ESC surface roughness, such as stylus profilometry, do not provide sufficient surface details. The inventors have determined the surface morphology parameters, S, of the ESC surface. a , S dr , S zTo render the surface morphology of the ESC surface properly, we have found advanced methods such as (but not limited to) laser confocal microscopy, atomic force microscopy (AFM), etc. These metrology methods and parameters will enable us to better finish the surface of new ESCs and also provide reliable refurbishment guidelines such as bead blasting and polishing the surface of used ESCs.

[0019]

[0024] FIG. 1 is a method 100 for planarizing an upper ceramic surface of an electrostatic chuck assembly. The electrostatic chuck assembly may include a complete ESC or may include only the wafer support portion of the ESC. In some embodiments, the ceramic may be aluminum oxide or aluminum nitride, or the like. In block 102, the electrostatic chuck assembly is placed in a first planarization apparatus. In some embodiments, the first planarization apparatus may be a machine-based planarization apparatus, including a lapping apparatus, a grinding apparatus, a polishing apparatus, a bead blasting apparatus, or a chemical mechanical planarization (CMP) apparatus, or the like. The techniques of the present principles are not limited by the type of planarization apparatus. In block 104, the upper ceramic surface of the electrostatic chuck assembly is modified by the first planarization apparatus. In particular, the surface morphology of the upper ceramic surface is modified to a more planarized state. In block 106, the modification of the upper ceramic surface of the electrostatic chuck assembly is stopped when a predetermined parameter is obtained for the surface morphology of the upper ceramic surface. In some embodiments, the parameters can be determined during the planarization process from an in situ metrology tool (confocal laser, AFM, etc.) associated with the first planarization tool or the second planarization tool.

[0020]

[0025] In some embodiments, to facilitate the modification of the ceramic surface, a surface morphology measurement may be performed on the upper ceramic surface prior to the modification of the ceramic surface. Estimating the time to modify the process may be performed by comparing a starting surface morphology parameter to a predetermined surface morphology parameter and based on the type of planarization equipment and the process. In some embodiments, stopping the modification of the upper ceramic surface of the electrostatic chuck assembly refers to stopping the modification of the upper ceramic surface by decreasing the arithmetic mean height (S a ) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S dr ) parameter is less than about 2.5 percent, and the maximum height of the upper ceramic surface (S z ) parameters are approximately 10mm above the top ceramic surface 2 and / or when the pit porosity depth parameter greater than 1 micron on the upper ceramic surface is less than about 0.1 percent of the area of ​​the upper ceramic surface. z The parameters are determined over an area approximately equal to the contact surface area of ​​the contact element. A typical contact element has an area of ​​approximately 10 mm 2 The present inventors have found that the contact or support surface area of ​​S z It has been discovered that the parameters should not exceed the height of the contact elements (see height 604 in FIG. 6). The contact elements may have a height of up to about 20 microns. In some embodiments, S z The parameters are less than about 10 microns within any given area of ​​the upper ceramic surface of the ESC to ensure minimal adverse effects on the contact elements located within any given area.

[0021]

[0026] In some embodiments, the same surface morphology parameters may be applied to the surfaces of the contact elements deposited on the ceramic surface of the electrostatic chuck, i.e., the method 100 includes modifying the top contact element surface of each of the plurality of contact elements with a second planarization device and determining the arithmetic mean height (S a) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S dr and stopping modifying the upper contact element surface of the electrostatic chuck assembly when a parameter of the maximum height (Sz) of the upper contact element surface is less than about 2.5 percent, a parameter of the maximum height (Sz) of the upper contact element surface is less than about 10 microns, or a parameter of a pit porosity depth greater than 1 micron on the upper contact element surface is less than about 0.1 percent of an area of ​​the upper contact element surface.

[0022]

[0027] In some embodiments, the second planarization device can be a machine-based planarization device, including a lapping device, a grinding device, a polishing device, a bead blasting device, or a chemical mechanical planarization (CMP) device. The techniques of the present principles are not limited by the type of planarization device. In some cases, the first planarization device and the second planarization device can be the same type of device or different types of devices. In some embodiments, if the ceramic surface and / or contact elements meet the predetermined parameters, the method 100 can be used in an electrostatic chuck refurbishment process to restore the electrostatic chuck to enable a local center find (LCF) position operating parameter of about 1 mm or less, or to produce a sheet resistance (Rs) non-uniformity (NU) operating parameter of about 2 percent or less.

[0023]

[0028] The predetermined parameters for stopping the modification process are based on the inventors' observations regarding the operation of an electrostatic chuck. As depicted in view 200A of FIG. 2, an upper ceramic portion 202A of an electrostatic chuck, with a recessed electrode 208 connected to a positive DC power supply 210, generates a positive charge 218 at the recessed electrode 208. The electric field of the recessed electrode 208 induces a negative charge layer 212A at the surface 220A of the upper ceramic portion 202A. The inventors have discovered that when the surface morphology of the upper ceramic portion 202A meets or exceeds the predetermined parameters as described above, the negative charge layer 212A at the surface 222A of the upper ceramic portion 202A is evenly distributed across the surface 220A. This even distribution creates an equal and opposite positive charge layer 214A on the backside 224A of the wafer 204a. The equal but opposite charge layer creates an attractive force that chucks the wafer 204A to the electrostatic chuck. At a minimum, the contact pads or contact elements 206A keep the wafer 204A separated from the surface 222A of the upper ceramic portion 202A by a distance equal to the height 220 of the contact elements 206A. A small positive charge layer 216A may form on the top surface of the contact elements 206A.

[0024]

[0029] The inventors have discovered that if the surface 222B of the ceramic portion 202B does not meet the above-mentioned predetermined parameters, the various charge layers will be non-uniform, as depicted in the view 200B of FIG. 2. The inventors have discovered that if the surface imperfections exceed the above-mentioned predetermined parameters, the negative charge layer 212B will be non-uniform, which will create a non-uniform positive charge layer 214B on the backside 224B of the wafer 204B and a non-uniform small positive charge layer 216B on the top surface of the contact element 206B. In some cases, areas with a higher density of charge layer interactions (attractive forces) can cause the wafer 204B to be off-center (LCF error) when placed on the electrostatic chuck for processing. An off-center wafer can cause many processing errors, such as non-uniform deposition and etching, leading to performance issues for structures formed on the wafer. Non-uniform charge layers can also cause longer dwell times when the DC chucking power is removed. Longer dwell times can result in attractive forces when lifting the wafer from the electrostatic chuck, which can cause surface damage to the electrostatic chuck or the backside of the wafer, or even dislodging of the contact elements from the ceramic surface of the electrostatic chuck. Particulate contamination caused by increased attractive dwell times can cause performance issues for processed wafers.

[0025]

[0030] As depicted in view 300 of FIG. 3, the inventors have investigated the surface of the ceramic portion 202B of the electrostatic chuck and investigated different types of damage or roughness found on the surface 222B. Pitting 306 on some of the surface 222B has been caused by erosion during wafer processing or by conformal deposition of the contact element 206B, whereby some of the contact element 308 has been lost in the pits during deposition (the deposition is conformal with the underlying ceramic surface), damaging the contact element 206B. The damaged contact element 206B has significantly reduced the performance of the contact element 206B, since the support surface 310 of the contact element 206B has been reduced. The inventors have also discovered that surface damage on the ceramic portion 202B dramatically increases the optimal separation distance 302A of the opposing charge layers between the backside of the wafer 204B and the surface 222B of the ceramic portion 202B. For example, a pit 306 in surface 222B nearly doubles the separation distance 302B, dramatically reducing the effect of the negative charge 304 formed on the surface at the bottom of the pit 306, reducing the holding force of the electrostatic chuck and increasing the discharge time due to the longer path (separation distance 302B).

[0026]

[0031] The inventors attempted to use conventional contact profilometers, such as linear stylus profilometers, to determine roughness parameters that would significantly degrade the performance of the electrostatic chuck. However, the inventors found that the average roughness of the two electrostatic chucks was measured in microinches or R a They found that even when the chucks were measured to be the same at 1000 nm, the chucking performance of the two electrostatic chucks was significantly different. Further investigation revealed that the stylus profilometer would not be able to distinguish between surface morphologies that alter chucking performance and those that do not substantially degrade chucking performance (R a The inventors have found that the arithmetic mean height S of the ceramic surface can be measured in the same way. The inventors have explored other means of characterizing the surface morphology and found that laser confocal microscopy provides a more useful three-dimensional measurement of the surface morphology. With the laser confocal data, multiple planes of the ceramic surface could be measured and a 3D model created. From the 3D model data, the arithmetic mean height Sa As depicted in view 400A of FIG. 4, the arithmetic mean height 402 is composed of the absolute values ​​of the peaks 404 and valleys 406 relative to a mean plane 408. The arithmetic mean height 402 represents the arithmetic mean of the absolute ordinate Z(x,y) and the evaluation area (surface area of ​​the ceramic surface). S a can be expressed as follows (Equation 1): where A is the surface area. TIFF2025503108000002.tif21170 The inventors have found that the arithmetic mean height 402 provides a stable result regarding the surface morphology of the electrostatic chuck because it is not significantly affected by scratches, contamination, or measurement noise. Furthermore, the inventors have used the maximum height (S z ) 410 may also be used. z can be expressed as follows (Equation 2). Here, S p is the height of the peak, and S v is the depth of the valley. TIFF2025503108000003.tif10170

[0027]

[0032] The inventors have also determined the interfacial developed area ratio S to further facilitate the determination of viable surface morphologies for the electrostatic chuck ceramic surface. dr The developed area ratio of the interface is the increase in surface area due to roughness / pitting. The increase is determined from the surface area A1 504 obtained from the projected area A0 502 as shown in the view 500 of FIG. 5. This ratio increases as the surface texture becomes finer or coarser. In terms of A1 504 and A0 502, S dr can be expressed as follows (Equation 3). TIFF2025503108000004.tif13170This ratio can be explicitly expressed as follows (Equation 4): TIFF2025503108000005.tif19170

[0028]

[0033] The inventors have evaluated each parameter and determined the relationship between the parameter and the chucking performance of the electrostatic chuck. a , the interface development area ratio S is less than about 2.5 percent dr , approximately 10 mm of the upper ceramic surface 2 A maximum height S of less than about 10 microns for any given area of z It has been found by the inventors that electrostatic chuck performance may be enhanced when the pit porosity depth is greater than 1 micron on the upper ceramic surface that is less than about 0.1 percent of the area of ​​the upper ceramic surface, or less than about 0.1 percent of the area of ​​the upper ceramic surface. In some embodiments, the arithmetic mean height (S a ) and an interface development area ratio (S dr ) provides a further improvement in the chucking force of the electrostatic chuck.

[0029]

[0034] The inventors have discovered that surface defects, undetectable by conventional means such as contact profilometry or optical measurements, contribute significantly to charge non-uniformity on the front and backside of the wafer, charge separation non-uniformity between the front and backside of the wafer, and contaminant formation (such as wafer pop-off due to residual charge during dechucking). Furthermore, the inventors have discovered that the defects also affect the ability of the chucking voltage to discharge when the chucking voltage potential is removed, increasing the residence time of the chucking charge and causing the wafer to stick to the electrostatic chuck when it is being lifted off the chuck after processing is complete. The inventors have discovered that pits increase the discharge path (see, e.g., separation distance 302B in FIG. 3) and increase the discharge time. The inventors have discovered that determining the area of ​​the pit / porosity defects at a depth of 1 micron 312 (see FIG. 3) provides a significant improvement in electrostatic chucks when the area of ​​the pit / porosity defects is less than 0.1 percent of the area of ​​the ceramic surface of the electrostatic chuck. Deep pits (e.g., greater than 5 microns) compromise the coating of the contact elements, and pits greater than 1 micron compromise the electrical contact to the backside of the wafer and the electronic conduction of the ceramic top surface, resulting in unstable or non-uniform charge separation and leading to electrostatic chucking failures, including increased Rs NU%, wafer slippage (LCF errors), backside gas pressure failures, and chucking / dechucking failures. a , S z , and S dr The surface parameters may be set to threshold values ​​that reduce the surface defect level so as not to substantially affect the chucking performance of the electrostatic chuck.

[0030]

[0035] The inventors have also realized that a similar technique of the present principles can be applied to contact elements 602, as depicted in view 600 of FIG. 6. A plurality of contact elements 602 can be deposited on a ceramic surface 610 of a ceramic portion 608 of an electrostatic chuck. In some embodiments, the contact elements 602 can have a height 604 of about 2 microns to about 20 microns. The height 604 of the contact elements 602 facilitates charge separation between the ceramic surface 610 of the electrostatic chuck and a wafer placed on the top surface 606 of the contact elements 602. The contact elements 602 also provide uniform separation of backside gas flow for cooling the wafer. In some embodiments, the contact elements 602 can be deposited using a diamond-like coating (DLC) material or the like. The contact elements 602 are conformally deposited on the ceramic surface 610. If the ceramic surface 610 meets the predetermined parameters described herein, the ceramic surface 610 can have a top surface 606 that closely mimics an optimal surface based on the techniques described herein.

[0031]

[0036] If the ceramic surface 610 is not prepared according to the present principles, the top surface 606 may contain the same imperfections found in the ceramic surface 610. The inventors have discovered that the same surface morphology parameters may also be applied to the top surface 606 of the contact element 602, regardless of the surface morphology of the ceramic surface 610. Providing a surface morphology to the top surface 606 of the contact element 602 will ensure that the contact element will perform at a high performance level. Ensuring that the surface morphology of both the contact element and the ceramic portion of the electrostatic chuck meets or exceeds the parameters defined herein allows the electrostatic chuck to perform at its highest level with minimal wafer positioning error, reduced or no contaminant formation, and reduced sheet resistance non-uniformity.

[0032]

[0037] The inventors have discovered that the present principles can be applied not only to new ESC manufacturing processes, but also to ceramic surface or contact element surface refurbishment processes to restore a refurbished electrostatic chuck assembly to enable a local center find (LCF) position operating parameter of about 1 mm or less, or to produce a sheet resistance (Rs) non-uniformity (NU) operating parameter of about 2 percent or less for the refurbished electrostatic chuck.

[0033]

[0038] Embodiments according to the present principles may be implemented in hardware, firmware, software, or any combination thereof. Embodiments may also be implemented as instructions stored using one or more computer-readable media, which may be read and executed by one or more processors. A computer-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing platform, or a "virtual machine" running on one or more computing platforms). For example, a computer-readable medium may include any suitable form of volatile or non-volatile memory. In some embodiments, a computer-readable medium may include a non-transitory computer-readable medium.

[0034]

[0039] While the forgoing is directed to embodiments of the present principles, other and further embodiments of the present principles may be devised without departing from the basic scope thereof.

Claims

1. 1. A method for planarizing an upper ceramic surface of an electrostatic chuck assembly, comprising: placing the electrostatic chuck assembly in a first planarization apparatus; modifying an upper ceramic surface of the electrostatic chuck assembly with the first planarization apparatus; The arithmetic mean height (S ａ ) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S ｄｒ ) is less than about 2.5 percent, and the maximum height (S ｚ ) parameter is about 10 mm from the upper ceramic surface ２ or ceasing the modifying of the upper ceramic surface of the electrostatic chuck assembly when a pit porosity depth parameter greater than 1 micron on the upper ceramic surface is less than about 0.1 percent of an area of ​​the upper ceramic surface. A method comprising:

2. The arithmetic mean height (S ａ ) parameter is less than about 0.1 microns, and the developed area ratio (S ｄｒ and ceasing said modifying said upper ceramic surface of said electrostatic chuck assembly when a parameter of said surface roughness is less than about 2.5 percent. The method of claim 1 further comprising:

3. The method of claim 1 , wherein the first planarization device comprises a bead blasting device, a polishing device, a lapping device, a grinding device, or a chemical mechanical planarization (CMP) device.

4. 10. The method of claim 1, wherein the upper ceramic surface has a plurality of contact elements disposed thereon, the plurality of contact elements having a height between about 2 microns and about 20 microns.

5. The method of claim 4 , wherein the plurality of contact elements are made of a diamond-like coating (DLC) material.

6. modifying an upper contact element surface of each of the plurality of contact elements with a second planarization device; The arithmetic mean height (S ａ ) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S ｄｒ ) is less than about 2.5 percent, and the maximum height (S ｚ ceasing the modification of the upper contact element surface of the electrostatic chuck assembly when a parameter of pit porosity depth greater than 1 micron on the upper contact element surface is less than about 0.1 percent of an area of ​​the upper contact element surface. The method of claim 4 further comprising:

7. The method of claim 6 , wherein the second planarization device comprises a bead blasting device, a polishing device, a lapping device, a grinding device, or a chemical mechanical planarization (CMP) device.

8. The arithmetic mean height (S ａ ) parameter, the developed area ratio of the interface of the upper ceramic surface (S ｄｒ ) parameters, about 10 mm of the upper ceramic surface ２ The maximum height (S ｚ determining an end point for stopping the modification of the upper ceramic surface using data from an in situ surface metrology device to determine at least one of a parameter of the surface roughness, ... The method of claim 1 further comprising:

9. 13. The method of claim 1, used in an electrostatic chuck assembly top ceramic surface refurbishment process to restore a refurbished electrostatic chuck assembly and enable a local center find (LCF) position operating parameter of about 1 mm or less, or produce a sheet resistance (Rs) non-uniformity (NU) operating parameter of about 2 percent or less.

10. 1. An apparatus for supporting a wafer on an upper surface of an electrostatic chuck, comprising: a plurality of contact elements disposed on the top surface of the electrostatic chuck, each of the plurality of contact elements having an upper contact element surface; Equipped with The upper contact element surface has an arithmetic mean height (S ａ ) parameter, and the developed area ratio of the interface (S ｄｒ ) parameters, the maximum height (S) of the upper contact element surface being less than about 10 microns; ｚ ) or a pit porosity depth parameter of greater than 1 micron that is less than about 0.1 percent of the area of ​​the upper contact element surface.

11. The surface morphology has an arithmetic mean height (S ａ ) parameter, and the interface development area ratio (S ｄｒ 11. The apparatus of claim 10, further comprising the parameters:

12. The apparatus of claim 10 , wherein each of the plurality of contact elements has a height between about 2 microns and about 20 microns.

13. The apparatus of claim 10 , wherein each of the plurality of contact elements is made of a diamond-like coating (DLC) material.

14. 1. A non-transitory computer readable medium having stored thereon instructions that, when executed, cause a method for planarizing an upper ceramic surface of an electrostatic chuck assembly to be performed, the method comprising: placing the electrostatic chuck assembly in a first planarization apparatus; modifying an upper ceramic surface of the electrostatic chuck assembly with the first planarization apparatus; The arithmetic mean height (S ａ ) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S ｄｒ ) is less than about 2.5 percent, and the maximum height (S ｚ ) parameter is about 10 mm from the upper ceramic surface ２ or ceasing the modifying of the upper ceramic surface of the electrostatic chuck assembly when a pit porosity depth parameter greater than 1 micron on the upper ceramic surface is less than about 0.1 percent of an area of ​​the upper ceramic surface. A non-transitory computer readable medium comprising:

15. The arithmetic mean height (S ａ ) parameter is less than about 0.1 microns, and the developed area ratio (S ｄｒ and ceasing said modifying said upper ceramic surface of said electrostatic chuck assembly when a parameter of said surface roughness is less than about 2.5 percent.

15. The non-transitory computer readable medium of claim 14, further comprising:

16. modifying the top ceramic surface of the electrostatic chuck assembly using the first planarization device, which may include a bead blasting device, a polishing device, a lapping device, a grinding device, or a chemical mechanical planarization (CMP) device; 15. The non-transitory computer readable medium of claim 14, further comprising:

17. The arithmetic mean height (S ａ ) parameter, the developed area ratio of the interface of the upper ceramic surface (S ｄｒ ) parameters, about 10 mm of the upper ceramic surface ２ The maximum height (S) of the upper ceramic surface is less than about 10 microns for any given area of ｚ determining an end point for stopping said modifying using data from an in situ metrology device to determine at least one of the parameters of the thickness of the ceramic layer, the thickness of the ceramic layer, the pit porosity depth of the upper ceramic surface, or the like; 15. The non-transitory computer readable medium of claim 14, further comprising:

18. 15. The non-transitory computer-readable medium of claim 14, wherein the upper ceramic surface has a plurality of contact elements disposed thereon, the plurality of contact elements having a height between about 2 microns and about 20 microns.

19. modifying an upper contact element surface of each of the plurality of contact elements using a second planarization device; The arithmetic mean height (S ａ ) parameter is less than about 0.1 microns, and the interfacial developed area ratio (S ｄｒ ) is less than about 2.5 percent, and the maximum height (S ｚ ceasing the modification of the upper contact element surface of the electrostatic chuck assembly when a parameter of pit porosity depth greater than 1 micron on the upper contact element surface is less than about 0.1 percent of an area of ​​the upper contact element surface.

20. The non-transitory computer readable medium of claim 18, further comprising:

20. The arithmetic mean height (S ａ ) parameter, the developed area ratio (S ｄｒ ) of the maximum height (S ｚ determining an end point for stopping the modification using data from an in-situ metrology device to determine at least one of the parameters of the thickness of the upper contact element surface, the thickness of the upper contact element surface, or the pit porosity depth of the upper contact element surface; 20. The non-transitory computer readable medium of claim 19, further comprising:

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