Helical multiphase electrode for electrostatic chuck

Abstract

The electrostatic chuck includes multiple electrodes, each of which has a spiral shape surrounding the center of the surface of the electrostatic chuck to achieve a multi-phase electrostatic chuck. Each electrode can be connected to a different phase of power. Each spiral shape can avoid each other as well as holes or openings in the surface of the electrostatic chuck. The spiral shapes can be determined algorithmically using a processor. These electrostatic chucks can include three or more electrodes. A method for manufacturing an electrostatic chuck includes determining the shape of each electrode and providing each electrode.

Description

Technical Field

[0001] The present disclosure is directed to electrodes for use in electrostatic chucks, and more particularly to spiral patterns of a plurality of electrodes for implementing a multi-phase electrostatic chuck. Background Art

[0002] Electrostatic chucks can be used to hold wafers in semiconductor processes. When operating an electrostatic chuck using alternating current (AC) voltage, different phases of the AC voltage can be used to help manage periodically occurring force loss. Two phases can be achieved by separate regions or an interdigitated design. Three or more phases can be implemented in separate regions. Using separate regions for each phase can cause wafer imbalance because the force exerted by different regions changes over time depending on the alternating current that is used. This can be particularly noticeable when there are other supports for the wafer, such as pins, and the wafer is held against the pins by the force of the electrostatic chuck, as the wafer may tilt around the support based on the force applied by different regions of the electrostatic chuck. Summary of the Invention

[0003] The present disclosure is directed to electrodes for use in electrostatic chucks, and more particularly to spiral patterns of a plurality of electrodes for implementing a multi-phase electrostatic chuck.

[0004] The alternating interlocking spiral pattern allows each of the multiple electrodes to surround the center of the electrostatic chuck without the need to divide the chuck into separate regions for each phase. This enables more stable holding of the wafer fixed to the chuck, suppressing positional fluctuations caused by power changes and specific phase losses due to the nature of alternating current. Furthermore, the suppression of positional fluctuations ensures that the distance remains constant, allowing for accurate and stable capacitance measurements at any point on the electrostatic chuck, such as determining whether the wafer is clamped or capacitance measurements used for other controls of the electrostatic chuck.

[0005] In one embodiment, the electrostatic chuck includes a plurality of electrodes formed on its surface in a helical pattern. Each of the plurality of electrodes is relative to the others. Fit together Each of the multiple electrodes surrounds the center of the surface.

[0006] In one embodiment, the surface is a ceramic surface. In one embodiment, the helical pattern is configured to avoid one or more holes formed on the surface. In one embodiment, the shape of the surface is substantially circular.

[0007] In one embodiment, each of the multiple electrodes is connected to a different circuit configured to supply power of a different phase. In one embodiment, each of the multiple electrodes has a starting point around its surface. In one embodiment, the multiple electrodes include at least three electrodes. In one embodiment, the multiple electrodes include at least six electrodes.

[0008] In one embodiment, a method for clamping a wafer includes placing the wafer on an electrostatic chuck and supplying power to each of a plurality of electrodes.

[0009] In one embodiment, a method for manufacturing an electrostatic chuck is to ensure that each electrode extends from a starting point to an ending point and surrounds the center of the surface. FittedThis includes determining a pattern on which multiple electrodes can be placed on a surface, and placing multiple electrodes on the surface according to the pattern.

[0010] In one embodiment, determining a pattern involves using an algorithm that determines a pattern based on the dimensions of the surface and any openings provided on the surface.

[0011] In one embodiment, the surface is a ceramic surface. In one embodiment, the pattern is configured to avoid one or more openings formed on the surface.

[0012] In one embodiment, providing multiple electrodes on a surface includes defining each electrode using photolithography. In one embodiment, providing multiple electrodes on a surface includes foil sintering. In one embodiment, providing multiple electrodes on a surface includes printing each electrode with conductive ink.

[0013] In one embodiment, the method further includes connecting each of a plurality of electrodes to a different circuit, each of which is configured to supply power having a different phase from the other circuit.

[0014] In one embodiment, the plurality of electrodes includes at least three electrodes. In another embodiment, the plurality of electrodes includes at least six electrodes. [Brief explanation of the drawing]

[0015] [Figure 1] A plan view of an electrostatic chuck according to one embodiment is shown. [Figure 2] A perspective view of an electrostatic chuck according to one embodiment is shown. [Figure 3] A flowchart of a method for manufacturing an electrostatic chuck according to one embodiment is shown. [Modes for carrying out the invention]

[0016] This disclosure relates to electrodes for use in electrostatic chucks, and more particularly to helical patterns of multiple electrodes for realizing a multiphase electrostatic chuck.

[0017] Figure 1 shows a plan view of an electrostatic chuck according to one embodiment. In the plan view of the electrostatic chuck 100 in Figure 1, the surface 102 can be seen along with the opening 104 and electrodes 106a to f.

[0018] Surface 102 is the surface of the electrostatic chuck 100 configured to face and / or contact the wafer. Surface 102 can include any suitable material, such as a dielectric material. Non-limiting examples of dielectric materials suitable for use on or as a surface of Surface 102 include polymer materials, glass materials, and / or ceramic materials. The dielectric material may be a bulk material or a thin film coating Surface 102. Surface 102 can have any shape suitable for an electrostatic chuck, such as substantially circular, square, or rectangular in plan view. In one embodiment, the periphery of Surface 102 may include recesses, protrusions, or any other features that deviate from the overall shape of the electrostatic chuck, such as recesses shown around the substantially circular surface of Surface 102 as shown in Figure 1.

[0019] The opening 104 is an opening formed in the surface 102. The opening 104 may be, for example, a passage for gas cooling, a location for housing a sensor such as a capacitance sensor or other suitable sensor.

[0020] Electrodes 106a to 106f are a plurality of electrodes provided on a surface 102, each having a helical shape, and the helical shape is such that electrodes 106a to 106f are relative to each other. Fitting together They are arranged as follows. In one embodiment, there may be a different number of electrodes than the six electrodes 106a to f shown in Figure 1. In one embodiment, there are two or more electrodes 106. In another embodiment, there are three or more electrodes 106. Each of the electrodes 106a to f may have a helical shape such that each electrode surrounds the center of the surface 102. In the electrodes 106a to f, each electrode is relative to the others. Fitting togetherarranged in such a pattern. The electrodes 106a to 106f are arranged such that each of the electrodes 106a to 106f does not contact or intersect each other. In one embodiment, each of the electrodes 106a to 106f has a helical shape, and the respective helical shape of each electrode has its respective start point and end point distributed around the surface 102. In one embodiment, the respective start points of the electrodes 106a to 106f can be evenly and radially distributed around the center of the surface 102, for example, when there are three electrodes 106, they are 120 degrees apart from each other, or as shown in FIG. 1, when there are six electrodes 106a to 106f, they are 60 degrees apart from each other. The pattern of the electrodes 106a to 106f can be determined algorithmically. In one embodiment, the electrode pattern is configured such that each of the electrodes 106a to 106f remains uninterrupted from its start point to its end point, and while each of the electrodes 106a to 106f remains separated from each other, the electrodes 106a to 106f avoid the opening 104 so as not to contact or intersect the opening 104.

[0021] FIG. 2 is an exploded cross-sectional view of an electrostatic chuck according to one embodiment. The electrostatic chuck 200 includes a base 202 and a surface 204. Optionally, one or more openings 206 may be provided in the surface 204. A plurality of electrodes 208a to 208f are provided. Each of the electrodes 208a to 208f may be connected to a corresponding power source 212a to 212f by a connection pin 210a to 210f. The electrostatic chuck 200 can be used to hold a wafer 214. In one embodiment, a second surface 216 may be provided between the electrodes 208a to 208f and the wafer 214.

[0022] The electrostatic chuck 200 holds a wafer such as the wafer 214 by providing an electrostatic force that clamps the wafer to the electrostatic chuck 200. The electrostatic chuck 200 can be used for any suitable type of wafer, such as a semiconductor wafer or an insulating wafer.

[0023] The base 202 may be the body of an electrostatic chuck 200 that supports the surface 204. In embodiments, the base 202 may optionally include a water and / or gas cooling system for cooling the chuck 200 and any clamped wafer 214. The gas cooling system may, for example, include channels 218 formed facing and within the surface of the base 202. The water cooling system may, for example, include flow paths 220 formed within the base 202. In embodiments, the wires 210a to 210f and / or the power supplies 212a to 212f schematically shown in FIG. 2 may be disposed within the base 202.

[0024] The surface 204 is a surface of the electrostatic chuck 200 configured to face the wafer 214 and / or come into contact with the wafer. The surface 204 may include any suitable material, for example a dielectric material. Non-limiting examples of dielectric materials suitable for use on or as the surface 204 include polymer materials, glass materials, and / or ceramic materials. The dielectric material may be a bulk dielectric material that constitutes part or all of the surface 204, or a thin film covering the surface 204.

[0025] The opening 206 is an opening formed in the surface 204. The opening 206 may be used, for example, as a flow path for gas cooling, a location accommodating any appropriate sensor or part of a sensor such as a ground pin of a capacitive sensor, a location accommodating an actuator such as a lift pin, or any other appropriate function within the electrostatic chuck. Some or all of the openings 206 may have different sizes. The size and position of each opening 206 may be suitable for the purpose of that specific opening.

[0026] Electrodes 208a to 208f are each separate electrodes of the electrostatic chuck 200. Electrodes 208a to 208f can be, for example, located on one or both sides of surface 204, and on one side of a second surface 216 facing surface 204. In one embodiment, there may be a different number of electrodes than the six electrodes 208a to 208f shown in Figure 1. In one embodiment, there are two or more electrodes 208. In one embodiment, there are three or more electrodes 208. Each of electrodes 208a to 208f may have a helical shape such that each electrode surrounds the center of surface 204. Electrodes 208a to 208f are arranged such that each electrode is relative to the others. Fitting together The electrodes 208a to 208f are arranged in such a pattern. The electrodes 208a to 208f are arranged so that none of them touch or intersect with each other. In one embodiment, each of the electrodes 208a to 208f has a substantially helical shape, and the starting and ending points of the helical shape of each electrode are distributed around the surface 204. In one embodiment, the starting points of each of the electrodes 208a to 208f can be distributed radially and evenly around the center of the surface 204, for example, if there are three electrodes 208, they are 120 degrees apart from each other, or if there are six electrodes 208a to 208f, they are 60 degrees apart from each other, as shown in Figure 2. The pattern of electrodes 208a to 208f can be determined algorithmically. In one embodiment, the electrode pattern is configured to avoid the opening 206 so that each of the electrodes 208a to 208f is continuous from its starting point to its ending point, while keeping each of the electrodes 208a to 208f separate from each other, so that the electrodes 208a to 208f do not touch or intersect with the opening 206. Electrodes 208a-f can avoid the opening 206 by curving around their respective openings 206, and other electrodes 208a-f may include similar curvature to avoid contact with other electrodes where the electrodes have deviated to avoid such openings 206.

[0027] Connection pins 210a-f allow each of the electrodes 208a-f to be connected to the corresponding power supplies 212a-f. Each power supply 212a-f supplies power to the respective connected electrode from among the electrodes 208a-f. In embodiments having a different number of electrodes 208, connection pins 210 and power supplies 212 may be present for each of the electrodes in that embodiment. Each of the power supplies 212a-f can supply alternating current (AC) power with a different phase or direct current (DC) power of a different polarity to each of the electrodes 208a-f, so that the loss of force due to power fluctuations in each of the electrodes 208a-f is temporally isolated from each other. In one embodiment, each of the power supplies 212a-f supplies AC power with a different phase. In one embodiment, one or more of the power supplies 212a-f supply DC power of each polarity. Thus, by using the power supplies 212a-f to supply power with a specific phase or polarity to each of the electrodes 208a-f, the clamping force can be maintained over time.

[0028] The wafer 214 is a wafer that can be held in the electrostatic chuck 200. In one embodiment, the wafer 214 is a semiconductor wafer. In one embodiment, the wafer 214 is an insulating wafer. A non-limiting example of an insulating wafer is a glass wafer. The alternating mating electrode structure described herein may be required to properly clamp a glass wafer. Furthermore, the wafer 214 can be held more uniformly by using the helical pattern of the alternating mating electrodes described herein. In one embodiment, the wafer 214 has a shape that substantially matches the shape of the surface 204, for example, the wafer 214 and the surface 204 are both substantially circular in shape. In embodiments, the wafer 214 and the surface 204 may each have a substantially rectangular shape, a substantially square shape, and so on. When electrodes 208a to f are receiving power, the wafer 214 can be clamped to the electrostatic chuck 200 by the force supplied by the powered electrodes 208a to f. In one embodiment, when the wafer 214 is clamped to the electrostatic chuck 200, the wafer 214 comes into contact with one or more protrusions (not shown) provided on or near the electrostatic chuck 200. In one embodiment, the protrusions that come into contact with the wafer 214 include two or more pins extending from the surface 204. In one embodiment, the presence of the wafer 214 can be detected by a capacitance sensor, such as one contained in one or more of the openings 206, or by at least some of the electrodes 208a to f themselves that function as capacitance sensors.

[0029] In embodiments, the second surface 216 can be provided on electrodes 208a-f. The second surface 216 can further cover portions of surface 204 that remain exposed by electrodes 208a-f. The second surface 216 may be, for example, one or more dielectric materials. Non-limiting examples of dielectric materials suitable for use on or as a surface of surface 204 include polymer materials, glass materials, and / or ceramic materials. The dielectric material may be a bulk dielectric material constituting part or all of surface 204, or a thin film covering surface 204.

[0030] In one embodiment, clamping the wafer 214 to the electrostatic chuck 200 can be performed by activating power supplies 212a~f and supplying power to each electrode 208a~f. Thus, each electrode 208a~f, when powered by its respective power supply 212a~f, can supply an electrostatic force, thereby clamping the wafer 214 to the electrostatic chuck 200. Different power phases can be selected so that the electrodes 208a~f continuously supply a clamping force, for example, by staggering the phases of at least some of the power supplies 212a~f from one another, thereby ensuring that at least one of the electrodes 208a~f always receives a non-zero amount of power. For example, the wafer 214 can be released from the electrostatic chuck 200 by cutting off the power supply from the power supplies 212a~f to each electrode 208a~f. Clamping and releasing can be performed on demand through control of the power supplies 212a~f or through the supply of power to each electrode 208a~f.

[0031] Figure 3 shows a flowchart of a method for manufacturing an electrostatic chuck according to one embodiment. Method 300 includes determining a pattern for providing a plurality of alternating mating electrodes in 302 and providing the electrodes in 304.

[0032] In 302, a pattern for providing a plurality of alternating mating electrodes is determined. The pattern can be such that each of the plurality of electrodes extends from a start point to an end point, and each electrode surrounds the center of the surface. The pattern is such that none of the plurality of electrodes touch or intersect with each other. The pattern may be helical with respect to each electrode included in the plurality of electrodes. The pattern can be based on the shape of the electrostatic chuck surface, such as circular, square, or rectangular. In embodiments, the pattern may include one or more electrodes configured to avoid openings in the surface on which the plurality of electrodes are provided. The plurality of electrodes may include any suitable number of electrodes for a multiphase electrostatic chuck for holding a wafer. In one embodiment, the plurality of electrodes includes at least three electrodes. In one embodiment, the plurality of electrodes includes an even number of electrodes. In one embodiment, the plurality of electrodes includes six electrodes.

[0033] In one embodiment, each electrode in the pattern determined in 302 may include a starting point around or near the surface of the electrostatic chuck and an ending point closer to the center of the surface of the electrostatic chuck compared to the starting point. The respective starting and / or ending points of each electrode in the pattern may be spaced radially apart from each other with respect to the center of the surface of the electrostatic chuck. In one embodiment, the starting and / or ending points of each electrode may be evenly distributed radially around the center of the surface of the electrostatic chuck, for example, if there are three electrodes they may be offset 120 degrees from each other, if there are four electrodes they may be offset 90 degrees from each other, if there are six electrodes they may be offset 60 degrees from each other, and so on.

[0034] In one embodiment, the pattern can be algorithmically determined in 302 using a processor based on inputs such as the number of electrodes to be provided, the size and shape of the surface on which the electrodes are provided, and the openings on the surface to be avoided by the electrodes.

[0035] The electrodes are provided on the surface in 304. The surface may be any surface suitable for an electrostatic chuck, such as a dielectric material. Examples of dielectric materials include, but are not limited to, ceramics, glass, and polymers. The surface may have any shape suitable for an electrostatic chuck, such as circular, square, or rectangular. The electrodes are provided on the surface in 304 according to the pattern determined in 302. The electrodes can be provided on the surface by any suitable means for forming the electrodes. Non-limiting examples of methods for providing electrodes in 304 include photolithography, foil sintering, or conductive ink printing. Non-limiting examples of photolithography may include depositing a conductive layer on the surface and defining the electrodes using photolithography, or a lift-off method in which the conductive layer is deposited on a photoresist and removed together with the photoresist. Foil sintering may include, for example, forming electrodes by sandwiching a molded bulk conductive foil between ceramic surfaces. The electrodes may be further formed so that each electrode has a contact configured to connect to a power source so that each electrode formed when the electrostatic chuck is operating can be powered by the power source. Printing using conductive ink may include, for example, silkscreen printing, which involves setting up electrodes in 304 using metallic ink according to a pattern determined in 302.

[0036] Pattern:

[0037] It is understood that any of embodiments 1 to 9 can be combined with any of embodiments 10 to 18.

[0038] Embodiment 1. A plurality of electrodes formed on the surface in a spiral pattern, wherein each of the plurality of electrodes is relative to each other Fit together An electrostatic chuck, in which multiple electrodes surround the center of the surface.

[0039] Embodiment 2. The electrostatic chuck according to Embodiment 1, wherein the surface is a ceramic surface.

[0040] Embodiment 3. The electrostatic chuck according to any one of Embodiments 1 to 2, wherein the spiral pattern is configured to avoid one or more holes formed on the surface.

[0041] Embodiment 4. An electrostatic chuck according to any one of Embodiments 1 to 3, wherein the surface shape is substantially circular.

[0042] Embodiment 5. An electrostatic chuck according to any one of Embodiments 1 to 4, wherein each of the multiple electrodes is connected to a different circuit configured to supply power of a different phase.

[0043] Embodiment 6. An electrostatic chuck according to any one of Embodiments 1 to 5, wherein each of the plurality of electrodes has a starting point around the surface.

[0044] Embodiment 7. An electrostatic chuck according to any one of Embodiments 1 to 6, wherein the plurality of electrodes include at least three electrodes.

[0045] Embodiment 8. An electrostatic chuck according to any one of Embodiments 1 to 7, wherein the plurality of electrodes include at least six electrodes.

[0046] Embodiment 9. A method for clamping a wafer, comprising placing the wafer on an electrostatic chuck described in any of Embodiments 1 to 8, A method comprising supplying power to each of a plurality of electrodes.

[0047] Embodiment 10. A method for manufacturing an electrostatic chuck, Each electrode extends from the starting point to the ending point, surrounding the center of the surface, Fitted To determine a pattern on which multiple electrodes can be placed on the surface, A method comprising providing multiple electrodes on a surface according to a pattern.

[0048] Embodiment 11: The method according to Embodiment 10, wherein determining the pattern involves using an algorithm that determines the pattern based on the dimensions of the surface and any openings provided on the surface.

[0049] Embodiment 12. The method according to any one of Embodiments 10 to 11, wherein the surface is a ceramic surface.

[0050] Embodiment 13. The method according to any one of embodiments 10 to 13, wherein the pattern is configured to avoid one or more openings formed on the surface.

[0051] Embodiment 14: The method according to any one of Embodiments 10 to 14, wherein providing a plurality of electrodes on a surface includes defining each of the electrodes using photolithography.

[0052] Embodiment 15: The method according to any one of Embodiments 10 to 14, wherein the provision of a plurality of electrodes on the surface is performed by foil sintering.

[0053] Embodiment 16: The method according to any one of Embodiments 10 to 14, wherein providing a plurality of electrodes on a surface includes printing each electrode with conductive ink.

[0054] Embodiment 17: The method according to any one of embodiments 10 to 16, further comprising connecting each of a plurality of electrodes to a different circuit, each of which is configured to supply power having a different phase from the other circuit.

[0055] Embodiment 18: The method according to any one of Embodiments 10 to 17, wherein the plurality of electrodes includes at least three electrodes.

[0056] Embodiment 19: The method according to any one of Embodiments 10 to 18, wherein the plurality of electrodes includes at least six electrodes.

[0057] The embodiments disclosed in this application should be considered in all respects to be illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than the foregoing description, and all modifications that are equivalent in meaning and scope to the claims are incorporated into the claims.

Claims

1. An electrostatic chuck comprising a plurality of electrodes formed in a helical pattern on its surface, wherein the plurality of electrodes include at least a first electrode and a second electrode, the helical pattern is configured to avoid a hole formed in the surface and the pattern is such that each electrode fits together with the others, each of the plurality of electrodes is continuous from its starting point to its ending point, each of the plurality of electrodes surrounds the center of the surface, the first electrode forms a curve around the hole to avoid the hole, and the second electrode forms a curve around the hole to avoid contact with the first electrode, An electrostatic chuck in which each of the plurality of electrodes is connected to a different circuit configured to supply power of different phases from each other.

2. The electrostatic chuck according to claim 1, wherein the plurality of electrodes do not come into contact with or cross each other.

3. The electrostatic chuck according to claim 1, wherein each of the plurality of electrodes has a starting point around the surface.

4. A method for manufacturing an electrostatic chuck, The present invention relates to determining a pattern on a surface such that each electrode extends continuously from a starting point to an ending point, surrounding the center of the surface, wherein the pattern is such that each electrode interlocks with the others, and the plurality of electrodes include at least a first electrode and a second electrode, and a hole is formed in the surface, the first electrode curves around the hole to avoid the hole, and the second electrode curves around the hole to avoid contact with the first electrode. The plurality of electrodes are provided on the surface according to the pattern, Each of the aforementioned multiple electrodes is connected to a different circuit configured to supply power with a different phase from the others. Methods that include...

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