Method, apparatus, and system for clamping a warped substrate

Abstract

A method and apparatus for clamping a substrate includes: i. placing a substrate on a clamping surface of a substrate support having a plurality of electrodes spaced apart from one another, including a first electrode and a second electrode; ii. measuring a substrate warp of the substrate; iii. determining a first voltage to be applied to the first electrode and a second voltage to be applied to the second electrode based on the measured substrate warp, wherein the first voltage is an AC voltage and the second voltage is an AC voltage or a DC voltage; and iv. applying the first voltage to the first electrode and the second voltage to the second electrode to clamp the substrate to the substrate support.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE

[0001] Embodiments of the present disclosure relate generally to clamping substrates, and more particularly to clamping warped substrates. [Background technology]

[0002]

[0002] Substrates, such as semiconductor wafers, can warp to the extent that clamping the substrate to a chuck becomes more difficult. For example, such warped substrates can be difficult to clamp to an electrostatic chuck (ESC) without an unacceptably high clamping voltage due to a large gap between the ESC and the substrate. A high clamping voltage can create a large clamping force between some areas of the substrate and the ESC, increasing friction between the substrate and the ESC and potentially generating undesirable particles.

[0003]

[0003] Therefore, the inventors propose a new method, system, and apparatus for clamping a substrate that can accommodate warped substrates using lower clamping voltages and reduce or eliminate the generation of unwanted particles. Summary of the Invention

[0004]

[0004] Provided herein are methods and apparatuses for clamping a substrate. In some embodiments, the method for clamping a substrate includes: i. placing a substrate on a clamping surface of a substrate support having a plurality of electrodes spaced apart, including a first electrode and a second electrode; ii. measuring a substrate warp of the substrate; iii. determining a first voltage to be applied to the first electrode and a second voltage to be applied to the second electrode based on the measured substrate warp, where the first voltage is an AC (alternating current) voltage and the second voltage is an AC voltage or a DC (direct current) voltage; and iv. applying the first voltage to the first electrode and the second voltage to the second electrode to clamp the substrate to the substrate support.

[0005]

[0005] In some embodiments, a system for clamping a substrate includes a substrate support having a surface for supporting the substrate, a plurality of electrodes spaced apart from one another within or on the substrate support, the plurality of electrodes including a first electrode and a second electrode, and a controller configured to receive a measurement value of substrate warp of the substrate, determine a first voltage to be applied to the first electrode and a second voltage to be applied to the second electrode based on the substrate warp, apply the first voltage to the first electrode and apply the second voltage to the second electrode, wherein the first voltage is an AC voltage and the second voltage is an AC voltage or a DC voltage.

[0006]

[0006] In some embodiments, a non-transitory computer-readable storage medium is provided having stored thereon instructions that, when executed by a processor of a system for clamping a substrate, perform a method of clamping a substrate, the system having a substrate support with a plurality of electrodes spaced apart from one another, including a first electrode and a second electrode, the method including: i. placing a substrate on a clamping surface of a substrate support having a plurality of electrodes spaced apart, the electrodes including a first electrode and a second electrode; ii. measuring a substrate warp of the substrate; iii. determining, based on the measured substrate warp, a first voltage to be applied to the first electrode and a second voltage to be applied to the second electrode, wherein the first voltage is an AC voltage and the second voltage is an AC voltage or a DC voltage; and iv. applying the first voltage to the first electrode and the second voltage to the second electrode.

[0007]

[0007] Other further embodiments of the present disclosure are described below.

[0008]

[0008] The embodiments of the present disclosure, briefly summarized above and described in more detail below, can be understood by reference to the exemplary embodiments of the present disclosure illustrated in the accompanying drawings. However, the accompanying drawings depict only typical embodiments of the present disclosure and are therefore not intended to limit the scope of the present disclosure, as other embodiments may be equally effective. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a plan view of a substrate support according to an embodiment of the present disclosure. [Figure 2] 2 is a cross-sectional view of the substrate support shown in FIG. 1 taken along section 2-2 of FIG. 1. [Figure 3] 3 shows the substrate support of FIG. 2 modified to include electrodes on multiple planes according to an embodiment of the present disclosure. [Figure 4] 3 illustrates the substrate support of FIG. 2 with electrodes connected to an AC voltage source and a DC voltage source according to an embodiment of the present disclosure. [Figure 5] 5 illustrates the substrate support of FIG. 4 modified to include electrodes on multiple planes according to an embodiment of the present disclosure. [Figure 6A] 10 is a cross-sectional view of another substrate support according to an embodiment of the present disclosure. [Figure 6B] 10 is a cross-sectional view of another substrate support according to an embodiment of the present disclosure. [Figure 6C] 10 is a cross-sectional view of another substrate support according to an embodiment of the present disclosure. [Figure 7] 1 shows a plan view of an electrode arrangement according to an embodiment of the present disclosure. [Figure 8] 1 shows a plan view of an electrode arrangement according to an embodiment of the present disclosure. [Figure 9] 1 shows a plan view of an electrode arrangement according to an embodiment of the present disclosure. [Figure 10] 1 shows a plan view of an electrode arrangement according to an embodiment of the present disclosure. [Figure 11A] 1 illustrates an interdigitated electrode arrangement according to an embodiment of the present disclosure. [Figure 11B] 1 illustrates an interdigitated electrode arrangement according to an embodiment of the present disclosure. [Figure 12] 1 illustrates a method for clamping a substrate according to an embodiment of the present disclosure. [Figure 13] 10 illustrates another method of clamping a substrate according to an embodiment of the present disclosure. [Figure 14]1 is a cross-sectional view of a substrate support and a bowed substrate in an unclamped configuration according to an embodiment of the present disclosure. [Figure 15] 15 shows the substrate of FIG. 14 clamped to the substrate support of FIG. 14. [Figure 16] 16 illustrates the clamped substrate and substrate support of FIG. 15 being clamped to an electrostatic chuck in a processing chamber according to an embodiment of the present disclosure. [Figure 17] 1 illustrates another embodiment of a substrate support according to an embodiment of the present disclosure. [Figure 18] 1 illustrates another embodiment of a substrate support according to an embodiment of the present disclosure. [Figure 19] 1 illustrates a method for controlling bowing of a substrate according to an embodiment of the present disclosure. [Figure 20] 1 illustrates a method for controlling bowing of a substrate according to an embodiment of the present disclosure. [Figure 21] 1 illustrates a method for controlling bowing of a substrate according to an embodiment of the present disclosure. [Figure 22] 1 illustrates another embodiment of a substrate support according to an embodiment of the present disclosure. [Figure 23] 1 illustrates another embodiment of a substrate support according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010]

[0033] To facilitate understanding, the same reference numerals have been used, wherever possible, to indicate identical elements common to the 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.

[0011]

[0034] Provided herein are embodiments of methods, systems, and apparatus for clamping a substrate. Such methods, systems, and apparatus can control clamping of a substrate based on measurements of the bow (curvature) of the substrate. Also provided herein are embodiments of methods, systems, and apparatus for controlling bow of a substrate.

[0012]

[0035] FIG. 1 illustrates a plan view of a substrate support 100 according to an embodiment of the present disclosure. In some embodiments, as shown in FIGS. 1-5, the substrate support 100 may include a base 102 and a plurality of electrodes 104 embedded in the base 102 and spaced apart from one another. In some embodiments, as shown in FIGS. 1-5, the plurality of electrodes 104 may be arranged concentrically. In some embodiments, the base 102 may be formed from at least one dielectric material, such as a ceramic oxide, a nitride, a polymer such as polyimide (PI) or benzocyclobutene (BCB), or a semiconductor (e.g., silicon). In some embodiments, the plurality of electrodes 104 may be formed from a metal, such as by screen printing and sintering metal electrodes within the base.

[0013]

[0036] In some embodiments, the substrate support 100 may be used as an electrostatic chuck. In some embodiments, as described in more detail below, the substrate support 100 may be used as a mobile carrier that is clamped to a substrate and can be moved throughout a substrate processing system and between processing chambers (e.g., in a cluster tool).

[0014]

[0037] In some embodiments, as shown in FIGS. 2-5 , the substrate support may include a plurality of mesas 106 extending axially (relative to the central axis A) from the base 102 to contact regions 108 for contacting the substrate. The contact regions 108 of the plurality of mesas 106 may collectively define a contact surface of the substrate support 100. In some embodiments, as shown in FIGS. 2-5 , the mesas 106 may be spaced apart from one another radially relative to the central axis A. In some embodiments, as shown in FIGS. 2-5 , all of the mesas 106 have the same height. As described in more detail below, in some embodiments, the mesas 106 may have different heights, as shown in FIGS. 20 and 21 .

[0015]

[0038] In some embodiments, the electrodes 104 may be spaced apart from one another radially relative to the axis A, as shown in Figures 1-5. In some embodiments, the electrodes 104 may be spaced apart from one another axially relative to the central axis A, as shown in Figures 3 and 5. In some embodiments, the electrodes 104 may have the same width (measured radially). In some embodiments, the electrodes 104 may have different widths, as shown in Figures 2-5.

[0016]

[0039] In some embodiments, as shown in FIGS. 2-5, the plurality of electrodes 104 may be configured to connect to one or more voltage sources 110 for generating an electrostatic charge for clamping the substrate to the substrate support 100. In some embodiments, as shown in FIG. 2, the base 102 has holes 202 exposing the plurality of electrodes 104, which may be removably connected to metal pins (e.g., pogo pins) or contacts 204 connected to the voltage source 110. In some embodiments, as shown in FIG. 3, wiring 302 is embedded within the base 102 and extends from each electrode 104 to a corresponding contact 304 on the outer (e.g., lower) surface 306 of the base 102. In some embodiments, the contacts 304 may be flush with the outer surface 306 (as shown in FIG. 3) or recessed. Such contacts 304 may be removably connected to metal pins (e.g., pogo pins) (not shown) or contacts 308 connected to the voltage source 110. Also, in some embodiments, the embedded wiring 302 and the multiple electrodes 104 may be formed together by screen printing and sintering metal traces within the base 102. In some embodiments, a single voltage source may be used and connected to the multiple electrodes 104 by a multiplexer.

[0017]

[0040] 1-5, the plurality of electrodes 104 may include a first electrode 104a and a second electrode 104b, and the voltage source 110 may be configured to apply a first voltage to the first electrode 104a and a second voltage to the second electrode 104b. In some embodiments, the first voltage is an AC voltage, and the second voltage is an AC voltage (FIGS. 2 and 3) or a DC voltage (FIGS. 4 and 5). The voltage source 110 may be configured to apply the first voltage and the second voltage simultaneously or sequentially.

[0018]

[0041] In some embodiments, as shown in FIGS. 2 and 3 , the first electrode 104a is connected to a voltage source 110 to receive an AC voltage, and the second electrode 104b is connected to a voltage source 110 to receive an AC voltage. In some embodiments, one or more voltage sources may be operatively coupled to a controller configured to control the application of voltage to the multiple electrodes 104. For example, in some embodiments, the controller may control one or more voltage sources 110, which may be configured to supply an AC or DC voltage. Each voltage source 110 may be configured to independently control the amplitude, phase, frequency, and duty cycle (in the case of an AC voltage) to one or more of the multiple electrodes 104. In some embodiments, as shown in FIGS. 4 and 5 , the first electrode 104a is connected to a voltage source 110 configured to supply an AC voltage, and the second electrode 104b is connected to a voltage source 110 configured to supply a DC voltage. In some embodiments, the second electrode 104b may also be connected to a voltage source 110 configured to supply an AC voltage, such that the AC voltage is superimposed on the DC voltage.

[0019]

[0042] Figure 6A shows an embodiment of a substrate support 100 arranged like the substrate support shown in Figure 1, but with the base 102 comprised of an upper dielectric layer 602a and a lower dielectric layer 602b. In the embodiment shown in Figure 6A, holes 202 are formed in the lower dielectric layer 602b.

[0020]

[0043] In some embodiments, the upper and lower dielectric layers 602a and 602b may be formed from one or more dielectric materials, such as ceramic oxides, nitrides, polymers (e.g., PI, BCB), or semiconductors (e.g., silicon). In some embodiments, a dielectric coating 604 may be applied to at least a portion of the base 102, as shown in FIG. 6A. In some embodiments, as shown in FIG. 6A, multiple electrodes 104 may be disposed within the upper dielectric layer 602a.

[0021]

[0044] In some embodiments, as shown in Figure 6B, the substrate support 100 shown in Figure 6A may be modified so that the plurality of electrodes 104 is disposed in the lower dielectric layer 602b. In some embodiments, at least one electrode of the plurality of electrodes 104 may be disposed in two or more dielectric layers, such as the upper dielectric layer 602a and the lower dielectric layer 602b. Also, in some embodiments, as shown in Figure 6C, the substrate support shown in Figure 6B may be further modified by including a buried material layer 606 made from an insulator, a conductor (e.g., a metal), or a polymer.

[0022]

[0045] 7-11B illustrate additional embodiments of electrode arrangements that can be used in a substrate support according to the present disclosure. In the embodiments shown in FIGS. 7-10, two electrodes are shown. In other embodiments, more than two electrodes may be arranged. In the embodiment shown in FIG. 7, the first electrode 702 may be arranged as a grid or wire frame, and the second electrode 704 may be formed as a square above or below the first electrode 702. In some embodiments, as shown in FIG. 8, the first electrode 802 and the second electrode 804 extend adjacent to each other in a substantially circular coil. In some embodiments, as shown in FIG. 9, the first electrode 902 and the second electrode 904 extend adjacent to each other in a substantially square or rectangular coil. In some embodiments, as shown in FIG. 10, the first electrode 1002 and the second electrode 1004 extend adjacent to each other in a substantially octagonal coil. The first and second electrodes in the arrangements shown in Figures 8-10 may be radially spaced apart from one another and / or axially spaced apart from one another.

[0023]

[0046] 11A and 11B illustrate additional electrode arrangements that can be used on a substrate support according to the present disclosure. In some embodiments, as shown in FIG. 11A, a first plurality of electrodes 1102 is interdigitated with a second plurality of electrodes 1104, and the first and second plurality of electrodes extend parallel to one another in the horizontal direction. In some embodiments, as shown in FIG. 11B, the first and second plurality of electrodes 1102 and 1104 are interdigitated to extend parallel to one another in the horizontal direction, and the third and fourth plurality of electrodes 1106 and 1108 are interdigitated to extend parallel to one another in the vertical direction. Thus, in the embodiment shown in FIG. 11B, the electrodes are interdigitated. Interdigitated electrode arrangements such as those shown in FIGS. 11A and 11B can extend the retention time of electrostatic charges on substrate supports arranged according to embodiments of the present disclosure.

[0024]

[0047] FIG. 12 illustrates a method of clamping a substrate using a substrate support according to embodiments of the present disclosure. In some embodiments, the method may begin at 1202 by placing a substrate on a support surface (e.g., contact region 108 of mesa 106) of the substrate support 100. The method may also include measuring the bow of the substrate at 1204. The bow can be measured in situ after the substrate is placed on the substrate support, or ex situ before the substrate is placed on the substrate support. In some embodiments, the substrate support 100 is located within a processing chamber and may be part of a movable substrate pedestal housed within the processing chamber. Such processing chambers can be used for lithography processes, dielectric and conductor etch processes, and deposition processes. In some embodiments, the substrate support 100 can be removably mounted within the processing chamber and used as a movable substrate carrier, as described in more detail below.

[0025]

[0048] The method may also include, at 1206, determining voltages to be applied to the plurality of electrodes 104 based on the measured bow of the substrate. For example, a first voltage to be applied to the first electrode 104a may be determined, and a second voltage to be applied to the second electrode 104b may be determined. As described above, in some embodiments, the first voltage may be an AC voltage, and the second voltage may be an AC voltage or a DC voltage. In some embodiments, the voltages may be determined using a lookup table of voltages corresponding to bow measurements. In some embodiments, determining the DC voltage to be applied to the second electrode may also include determining an AC voltage to be superimposed on the DC voltage.

[0026]

[0049] According to some embodiments, at 1208, the determined voltage may be applied to one or more of the plurality of electrodes 104. For example, a first voltage may be applied to the first electrode 104a and a second voltage may be applied to the second electrode 104b. The voltages may be applied simultaneously or sequentially. In some embodiments, before substrate processing (e.g., etching or deposition) begins on the substrate, a verification may be performed at 1210 to determine whether a voltage is applied to all of the plurality of electrodes 104. If not (NO at 1210), further voltage determinations and voltage applications may be performed until a voltage is applied to all of the plurality of electrodes 104. According to some embodiments, if a voltage is applied to all of the plurality of electrodes 104 (YES at 1210), substrate processing may be performed at 1212. In some embodiments, the method may end at 1214 once substrate processing is complete, as shown in FIG. 12 .

[0027]

[0050] 13 illustrates another method 1300 of clamping a substrate, including the method 1200 of FIG. 12 modified according to embodiments of the present disclosure. Specifically, in some embodiments, the method includes measuring substrate bow 1302 of the same substrate, and if the bow is determined not to be optimized at 1304 (NO at 1304), determining an electrode voltage 1206, and applying a voltage to the electrode 1208. Otherwise, in such embodiments, if the bow is determined to be optimized (YES at 1304), substrate processing occurs at 1212. Also, in some embodiments, during substrate processing at 1212, the bow measurement value can be continuously or periodically checked to determine whether the bow is optimized, and if not, an updated electrode voltage can be determined and applied to the electrode to adjust the clamping force on the substrate.

[0028]

[0051] In some embodiments, wafer bow can be determined to be optimized when variations in at least one of clamping pressure, substrate bow, or heat transfer flux are minimized. In some embodiments, wafer bow can be determined to be optimized when the substrate bow is at or below a predetermined substrate bow (e.g., average substrate bow), the clamping pressure meets or exceeds a predetermined clamping pressure (e.g., average clamping pressure), or the heat transfer flux meets or exceeds a predetermined heat transfer flux (e.g., average heat transfer flux). As described above, embodiments of the substrate support according to the present disclosure may be used as a mobile carrier to carry substrates throughout multiple processing chambers, which may be part of a cluster tool. Substrate supports according to embodiments of the present disclosure may be used as a mobile carrier by clamping the substrate to the substrate support according to embodiments of the clamping methods described herein and then moving the substrate and carrier together after clamping. For example, in some embodiments, a warped substrate 1402 can be placed on the substrate support 100, as shown in FIG. 14 . Positioning and clamping of the substrate 1402 to the substrate support 100 can be performed inside or outside of a processing chamber according to any embodiment of the clamping methods described herein. In some embodiments, during clamping, the plurality of electrodes 104 may be connected to a voltage source, such as by connecting pin contacts of the voltage source to exposed electrodes of the substrate support, as described above with respect to the substrate support 100. Once the substrate 1402 is clamped to the substrate support 100, the voltage source can be disconnected from the plurality of electrodes 104, such as by removing the pin contacts of the voltage source from the exposed electrodes and ceasing application of voltage to the plurality of electrodes 104. FIG. 15 illustrates the substrate 1402 clamped to the substrate support 100 and disconnected from the voltage source.

[0029]

[0052] After the electrodes 104 are disconnected from the voltage source, the substrate 1402 may remain clamped to the substrate support 100 due to the presence of residual electrostatic charge between the substrate 1402 and the substrate support 100. In some embodiments, based on the arrangement of the multiple electrodes 104 within the substrate support 100, the residual electrostatic charge may have a lifetime on the order of hours to days, thereby preventing the substrate 1402 from being unclamped or released from the substrate support 100 for several hours to days.

[0030] In some embodiments, after the substrate 1402 is clamped to the substrate support 100, both the substrate 1402 and the substrate support 100 may be moved together into a processing chamber 1602 having an electrostatic chuck 1604, as shown in FIG. 16 . In some embodiments, the substrate support 100 may be placed on the electrostatic chuck 1604 and electrostatically clamped thereto, as shown in FIG. 16 , thereby securing both the substrate 1402 and the substrate support 100 to the electrostatic chuck 1604. In some embodiments, the electrostatic chuck 1604 may include a plurality of pin contacts configured to contact the plurality of electrodes 104. Such pin contacts may be connected to a voltage source, as described above, to apply AC or DC voltages to the plurality of electrodes 104, allowing the clamping force on the substrate 1402 to be adjusted before and / or during substrate processing. For example, in some embodiments, after the substrate 1402 and the substrate support 100 are transferred to the electrostatic chuck, an AC or DC voltage (e.g., a third voltage) may be applied to one electrode (e.g., the first electrode 104a) of the plurality of electrodes 104, and an AC or DC voltage (e.g., a fourth voltage) may be applied to another electrode (e.g., the second electrode 104b) of the plurality of electrodes 104.

[0031]

[0053] In some embodiments, after substrate processing in the processing chamber 1602 is completed, the substrate support 1400 can be removed (unclamped) from the electrostatic chuck 1604, and the substrate 1402 and the substrate support 100 can be transported together out of the processing chamber 1602. In some embodiments, if additional substrate processing is required, the substrate 1402 and the substrate support 100 can be transported to another processing chamber for additional substrate processing. Alternatively, in some embodiments, if no further substrate processing is required, the substrate 1402 can be unclamped from the substrate support 100 by at least one of exposing the substrate to an ultraviolet (UV) flash, applying a reverse voltage to the voltage applied to clamp the substrate, or heat soaking the substrate at an elevated temperature.

[0032]

[0054] 17 and 18 illustrate substrate support 100 with mesas 106 having different heights, according to embodiments of the present disclosure. In some embodiments, the height difference between mesas 106 may vary between 0.1 μm and 2 mm. In some embodiments, as shown in FIG. 17, mesas 106 have contact regions 108 that collectively define a convex support surface of substrate support 100 suitable for supporting concave surface 1702 of substrate 1704. In some embodiments, as shown in FIG. 18, mesas 106 have contact regions 108 that collectively define a concave support surface of substrate support 100 suitable for supporting convex surface 1802 of substrate 1804.

[0033]

[0055] In some embodiments, the substrate support 100 may include one or more electrodes 1706, as shown in FIGS. 17 and 18. For example, in some embodiments, the substrate support 100 shown in FIGS. 17 and 18 may include multiple electrodes 104, as described above. In some embodiments, the varying heights of the mesas 106 may facilitate uniform contact between the contact areas 108 of the mesas 106 and uneven or irregular backside surfaces of substrates, such as substrates 1704 and 1804, which may facilitate localization of surface charges on the substrates 1704 and 1804. Improving contact between the mesas 106 and the substrates 1704 and 1804 may also improve heat transfer between the substrates 1704 and 1804 and the substrate support 100. Furthermore, varying the height of the mesas 106 to more closely match the concave or convex surface 1702 or 1802 may reduce the voltage applied to one or more electrodes 1706, thereby reducing the clamping force on the substrates 1704 and 1804. Such a reduction in clamping force can further reduce friction (and unwanted particle generation) between the substrate 1704, 1804 and the substrate support 100.

[0034]

[0056] In some embodiments, the mesas 106 may have the same cross-sectional shape and size. In some embodiments, the cross-sectional shapes and sizes of the mesas 106 may vary. For example, in some embodiments, some mesas of the mesas 106 may have a cylindrical, pyramidal, frustoconical, or annular cross-section. Also, in some embodiments, the radial spacing between the mesas 106 may be constant. In some embodiments, the radial spacing between one or more mesas 106 may vary.

[0035]

[0057] In some embodiments, the height difference between the mesas 106 may be fixed. For example, some substrates are observed to have a predictable or known warp or irregular backside, which can be compensated for by a substrate support with fixed mesas having heights that complement the irregular backside contour. In some embodiments, the height of the mesas 106 may be adjustable to fit any irregular contours of the substrate's backside. For example, if random variations in the substrate's backside are observed, being able to adjust the height of the mesas 106 may be advantageous to maximize contact between the mesas 106 and the substrate. In some embodiments, the mesas 106 may be independently axially adjustable, such as by a respective piezoelectric actuator connected to each mesa 106. In some embodiments, the height of the mesas 106 may be actively adjusted (i.e., by feedback control) based on measurements of electrostatic clamping force or substrate warpage.

[0036]

[0058] A method for controlling substrate bow of a substrate can include selectively depositing a material on at least a portion of the backside of the substrate. In some embodiments, the material can include a polymer (e.g., Kapton) or an inorganic material (e.g., diamond or diamond-like material). Such selective deposition can help reduce substrate deformation by adding material to the substrate at selective locations on the substrate, thereby advantageously facilitating clamping the substrate at lower clamping voltages. Also, in some embodiments, a subtractive process can be used to remove excess deposited material. In some embodiments, the subtractive process can include etching. In some embodiments, the deposition can include photolithography and inkjet printing. The backside deposition can be performed with or without breaking vacuum.

[0037]

[0059] 19-21 illustrate a method 1900 for controlling bowing of a substrate according to an embodiment of the present disclosure. In some embodiments, as shown in FIG. 20, at the start of the method, at 1902, a bowed substrate 2000 is received, and at 1904, the bowed substrate 2000 is clamped to a substrate support 100 according to an embodiment of the present disclosure. Also, in some embodiments, the substrate support 100 may include multiple heating elements configured to control the temperature of multiple heating zones of the substrate support.

[0038]

[0060] In some embodiments, a heat-sensitive coating 2006 can be applied to the backside 2002 at 1906, as shown in FIG. 20 . In some embodiments, the coating 2006 can be applied by various methods, such as spraying, inkjet printing, or applying a pre-formed thin film to the backside of the substrate. The applied coating 2006 can initially have a uniform thickness. In some embodiments, the coating 2006 can be a statistically deterministic non-uniform coating, a thin film with different reaction rates based on temperature. For example, such a coating 2006 can stretch and thin when exposed to high temperatures. In some embodiments, the coating 2006 can be made from an insulating oxide, carbide, or nitride (e.g., silicon oxide / carbide / nitride, aluminum oxide / carbide / nitride).

[0039]

[0061] Once clamped, the heating elements can be set to different temperatures for a period of time to apply non-uniform temperatures to the substrate 2000 and coating 2006 at 1908, causing different portions of the coating 2006 to react and thin at different rates. After the coating 2006 has been non-uniformly heated for a period of time, the thickness of the coating 2006 will be non-uniform. At 1910, the substrate 2000 can be removed from the substrate support 2004, leaving the coating 2006 to stiffen the substrate 2000 to prevent it from returning to a bowed configuration. The method can end at 1912.

[0040]

[0062] Another method of controlling substrate bow in accordance with the present disclosure may include selectively depositing material on the substrate support surface of the electrostatic chuck to more closely conform to the contours of the backside of the substrate, minimizing the gap between the substrate support surface and the backside. The materials and methods for depositing and removing material described above for deposition on a substrate can also be used for deposition on an electrostatic chuck. In some embodiments, after the electrostatic chuck has been used for substrate processing, the deposited material can be removed by any subtractive method to prepare the electrostatic chuck for further substrate processing.

[0041]

[0063] 22 and 23 illustrate further embodiments of a substrate support 2200 for clamping a substrate. The substrate support 2200 includes multiple pressure zones 2202 separated by multiple seal bands 2204 configured to seal against the backside of the substrate. Such seal bands may be O-rings. In some embodiments, as shown in FIG. 22, the multiple pressure zones are pixelated and defined by seal bands 2204 at discrete locations on the substrate support 2200. Such seal bands 2204 may not be coaxially aligned. In some embodiments, as shown in FIG. 21, the multiple pressure zones 2202 are annular and defined by coaxially aligned seal bands 2204.

[0042]

[0064] In some embodiments, the pressure in each pressure zone 2202 can be independently controlled to adjust the clamping force on the portion of the substrate sealed to each pressure zone 2202. In some embodiments, each pressure zone 2202 can have an individual vacuum opening 2206 in the substrate support 2200 connected to a vacuum source 2208. Also, in some embodiments, each pressure zone can have a gas supply opening 2210 for supplying a gas, such as helium, to each pressure zone. Gas flow can be used as a heat transfer medium to control the temperature of the substrate and for pressure control within each pressure zone 2202. Thus, in some embodiments, gas can be introduced into the same pressure zone 2202 that is connected to a vacuum source. The pressure in each pressure zone 2202 can be adjusted by adjusting at least one of the vacuum source or the gas flow.

[0043]

[0065] In use, the substrate can be clamped to the substrate support by placing the backside of the substrate on the substrate support 2200 and contacting the plurality of seal bands 2204. The bow of the substrate can be measured and the pressure in each pressure zone 2202 can be adjusted to adjust the bow of the substrate. For example, in some embodiments, the pressure in the pressure zones 2202 can be controlled to minimize wafer bow of the substrate.

[0044]

[0066] While the forgoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof.

Claims

1. 1. A method for clamping a substrate, comprising: i. placing a substrate on a clamping surface of a substrate support having a plurality of spaced apart electrodes including a first electrode and a second electrode; ii. Measuring the substrate warpage of the substrate; iii. determining a first voltage to be applied to the first electrode and a second voltage to be applied to the second electrode based on the measured substrate bow, wherein the first voltage is an AC voltage and the second voltage is an AC voltage or a DC voltage; iv. applying the first voltage to the first electrode and the second voltage to the second electrode to clamp the substrate to the substrate support; A method comprising:

2. The method of claim 1 , further comprising repeating steps ii, iii, and iv until the substrate bow of the substrate is determined to be optimized.

3. The method of claim 1 or 2, further comprising applying a non-uniform coating to the substrate while the substrate is clamped to the substrate support.

4. The method of claim 1 or 2, wherein the first voltage and the second voltage are applied sequentially.

5. The method of claim 1 or 2, wherein the first voltage and the second voltage are applied simultaneously.

6. ceasing application of the first voltage to the first electrode and the second voltage to the second electrode; transferring the clamped substrate and the substrate support together to a processing chamber having an electrostatic chuck and electrostatically coupling the substrate support to the electrostatic chuck; After the transfer, applying a third voltage to the first electrode and a fourth voltage to the second electrode, wherein the third voltage is an AC voltage or a DC voltage, and the fourth voltage is an AC voltage or a DC voltage; and The method of claim 1 further comprising:

7. The method of claim 1 or 2, wherein the second voltage is an AC voltage.

8. The method of claim 1 or 2, wherein applying the second voltage to the second electrode comprises simultaneously applying a DC voltage and an AC voltage to the second electrode.

9. 1. A system for clamping a substrate, comprising: a substrate support having a surface for supporting a substrate; a plurality of electrodes spaced apart from one another in or on the substrate support, the plurality of electrodes including a first electrode and a second electrode; a controller configured to receive a measurement of substrate bow of the substrate, determine a first voltage to be applied to the first electrode and a second voltage to be applied to the second electrode based on the substrate bow, and apply the first voltage to the first electrode and the second voltage to the second electrode, wherein the first voltage is an AC voltage and the second voltage is an AC voltage or a DC voltage; A system comprising:

10. 10. The system of claim 9, wherein the controller is configured to optimize substrate bow of the substrate by iteratively receiving a measurement of substrate bow, determining the first voltage and the second voltage, and re-applying the first voltage and the second voltage based on the received measurement of substrate bow.

11. The system of claim 9 or 10, wherein the plurality of electrodes are arranged interdigitated.

12. 11. The system of claim 9 or 10, wherein the controller is configured to apply the first voltage and the second voltage sequentially.

13. 11. The system of claim 9 or 10, wherein the controller is configured to apply the first voltage and the second voltage simultaneously.

14. The system of claim 9 , further comprising an electrostatic chuck, the substrate support configured to removably couple to the electrostatic chuck.

15. 11. The system of claim 9 or 10, wherein the second voltage is an AC voltage.

16. 11. The system of claim 9 or 10, wherein the controller is configured to simultaneously apply a DC voltage and an AC voltage to the second electrode.

17. A non-transitory computer-readable storage medium having instructions stored thereon, the instructions, when executed by a processor of a system for clamping a substrate, the system having a substrate support with a plurality of spaced apart electrodes including a first electrode and a second electrode, performing a method of clamping a substrate, the method comprising: i. placing a substrate on a clamping surface of a substrate support having a plurality of spaced apart electrodes, including a first electrode and a second electrode; ii. Measuring the substrate warpage of the substrate; iii. determining a first voltage to be applied to the first electrode and a second voltage to be applied to the second electrode based on the measured substrate bow, wherein the first voltage is an AC voltage and the second voltage is an AC voltage or a DC voltage; iv. applying the first voltage to the first electrode and the second voltage to the second electrode; 1. A non-transitory computer-readable storage medium, comprising:

18. 20. The non-transitory computer-readable storage medium of claim 17, wherein the method further comprises repeating ii, iii, and iv until substrate bow of the substrate is determined to be optimized.

19. 19. The non-transitory computer-readable storage medium of claim 17 or 18, wherein the second voltage is an AC voltage.

20. 19. The non-transitory computer-readable storage medium of claim 17 or 18, wherein applying the second voltage to the second electrode comprises simultaneously applying a DC voltage and an AC voltage to the second electrode.

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