JP6634109B2 - Manufacturing method of electrostatic chuck - Google Patents

Description

  The technology disclosed in the present specification relates to a method for manufacturing a ceramic member having a conductive portion.

  For example, an electrostatic chuck is used as a holding device for holding a wafer when manufacturing a semiconductor. The electrostatic chuck is provided inside a ceramic member having a substantially planar surface (hereinafter, referred to as “adsorption surface”) substantially perpendicular to a predetermined direction (hereinafter, referred to as “first direction”). And chucking the wafer on the suction surface of the ceramic member using electrostatic attraction generated by applying a voltage to the chuck electrode.

  If the temperature of the wafer held on the suction surface of the electrostatic chuck does not reach the desired temperature, the accuracy of each processing (film formation, etching, etc.) on the wafer may be reduced. The ability to control the distribution is required. Therefore, for example, a plurality of heater electrodes are provided inside the ceramic member. When a voltage is applied to each heater electrode, each heater electrode generates heat, thereby heating the ceramic member, thereby controlling the temperature distribution on the suction surface of the ceramic member (and, consequently, the temperature of the wafer held on the suction surface). Distribution control) is realized.

  As described above, the following method is known as a method for manufacturing a ceramic member having a conductive portion such as a chuck electrode or a heater electrode. That is, a conductor paste layer formed of an epoxy resin, a phenol resin, or the like is printed on the green sheet to form a conductor paste layer. Next, by laminating and firing a plurality of green sheets including the green sheet on which the conductive paste layer is formed, a ceramic member having a conductive portion can be manufactured. Another method is as follows. That is, a green sheet containing metal particles or conductive ceramic particles is formed, and a conductive pattern (for example, a pattern of a resistance heating element) is punched from the green sheet. Next, the punched conductive pattern is sandwiched between ordinary green sheets having no conductivity and fired, whereby a ceramic member having a conductive portion can be manufactured (for example, see Patent Document 1).

JP 2005-26585 A

  In the above-described manufacturing method in which the conductive paste is printed on the green sheet, the conductive paste has a low formality that maintains the shape, and thus it is difficult to accurately form the conductive pattern on the green sheet into a shape corresponding to the conductive portion. is there. On the other hand, in the above-described manufacturing method in which the punched conductive pattern is sandwiched between the green sheets, when the conductive pattern is sandwiched between the green sheets, there is a possibility that the arrangement position of the conductive pattern on the green sheet is shifted from a regular position. is there. As described above, the reduction in the precision of the shape of the conductive portion and the displacement of the conductive portion cause poor conductivity between the conductive portion and another conductor in the ceramic member and a decrease in the function of the conductive portion.

  Such a problem is not limited to an electrostatic chuck that holds a wafer by using an electrostatic attraction, but is generally a common problem including a ceramic member having a conductive portion (for example, a component for a semiconductor manufacturing apparatus).

  This specification discloses a technique capable of solving at least a part of the above-described problem.

  The technology disclosed in this specification can be realized as the following modes.

(1) A method for manufacturing a ceramic member disclosed in the present specification includes, in the method for manufacturing a ceramic member having a conductive portion, a conductive material and a curable resin that is cured by at least one of heat and light. And a step of preparing a semi-cured sheet having conductivity at least after firing and in a semi-cured state, and forming a semi-cured conductive pattern having a shape corresponding to the conductive portion from the semi-cured sheet, Forming the conductive part precursor adhered on the ceramic green sheet by disposing the semi-cured conductive pattern on a ceramic green sheet and curing the conductive part by at least one of heat and light; A plurality of ceramic green sheets, including the ceramic green sheet to which the body is adhered, are stacked and fired And by, and forming the ceramic member comprising the conductive portion includes a conductive portion. For example, if an attempt is made to form a conductive pattern from a non-curable conductive paste that does not contain a curable resin, the non-curable conductive paste has a low formality that maintains its shape, and the conductive pattern is formed into a shape corresponding to the conductive part. It is difficult to form it with high precision. In contrast, in the present manufacturing method, a semi-cured conductive pattern is formed from a semi-cured sheet in a semi-cured state. Since the semi-cured sheet has higher formability than the non-curable conductive paste described above, the semi-cured conductive pattern is more accurately formed into a shape corresponding to the conductive part than when using the non-curable conductive paste. can do. Further, in the present manufacturing method, the semi-cured conductive pattern is disposed on the ceramic green sheet and cured by at least one of heat and light to form a conductive part precursor bonded to the ceramic green sheet. Thereby, the handleability of the ceramic green sheet on which the conductive part precursor is formed is improved. For example, when a plurality of ceramic green sheets, including a ceramic green sheet to which a conductive part precursor is bonded, are stacked, displacement of the conductive part precursor on the ceramic green sheet is suppressed.

(2) In the method for manufacturing a ceramic member having a conductive portion according to the above (1), the ceramic member includes a plurality of the conductive portions having substantially the same shape as each other, and the semi-cured conductive pattern is formed. In the forming step, a plurality of the semi-cured sheets are overlapped and collectively subjected to a punching process to collectively form a plurality of the semi-cured conductive patterns having a shape corresponding to the conductive part, as a configuration including a conductive part. Is also good. In the present manufacturing method, a plurality of semi-cured conductive patterns having a shape corresponding to the conductive part are collectively formed by stacking a plurality of semi-cured sheets and performing punching. Thereby, compared to the case where a plurality of semi-cured conductive patterns are individually formed, it is possible to improve the identity of the shapes of the plurality of semi-cured conductive patterns and reduce the number of manufacturing steps.

(3) The ceramic member disclosed in the present specification includes a ceramic portion, and a conductive portion disposed on the ceramic portion and including particles of a conductive material, and at least a part of a surface of the conductive portion is provided. The cut surface of the particles of the conductive material is exposed. According to the present ceramic member, the cut surface of the particles of the conductive material is exposed on at least a part of the surface of the conductive portion. As a result, compared to a configuration in which uncut conductive material particles protrude from the surface of the conductive portion in a convex shape, the accuracy of the shape of the conductive portion is high, so that the thickness and width of the conductive portion are suppressed from varying. can do.

  The technology disclosed in the present specification can be realized in various forms, for example, a holding device, an electrostatic chuck, a heater device such as a CVD heater, a vacuum chuck, a shower head, and other conductive portions. It can be realized in the form of a ceramic member provided with

FIG. 1 is a perspective view schematically illustrating an external configuration of an electrostatic chuck 100 according to an embodiment. FIG. 2 is an explanatory diagram schematically showing an XZ cross-sectional configuration of the electrostatic chuck 100 according to the embodiment. FIG. 3 is an explanatory diagram schematically illustrating an XY plane (upper surface) configuration of the electrostatic chuck 100 according to the embodiment. FIG. 4 is an explanatory diagram schematically showing an XY cross-sectional configuration of one heater electrode 500 arranged in one segment SE. 4 is a flowchart illustrating a method for manufacturing the electrostatic chuck 100. FIG. 4 is an explanatory diagram illustrating an outline of a punching process in a method for manufacturing the electrostatic chuck 100. FIG. 4 is an explanatory diagram illustrating an outline of a process of arranging a semi-cured conductive pattern in a method of manufacturing the electrostatic chuck 100.

A. Embodiment:
A-1. Configuration of electrostatic chuck 100:
FIG. 1 is a perspective view schematically illustrating an external configuration of the electrostatic chuck 100 according to the present embodiment, and FIG. 2 is an explanatory diagram schematically illustrating an XZ cross-sectional configuration of the electrostatic chuck 100 according to the present embodiment. FIG. 3 is an explanatory diagram schematically showing an XY plane (upper surface) configuration of the electrostatic chuck 100 according to the present embodiment. Each drawing shows XYZ axes orthogonal to each other for specifying the direction. In this specification, for the sake of convenience, the positive direction of the Z axis is referred to as an upward direction, and the negative direction of the Z axis is referred to as a downward direction. However, the electrostatic chuck 100 is actually installed in a direction different from such a direction. May be done.

  The electrostatic chuck 100 is a device that attracts and holds an object (for example, a wafer W) by electrostatic attraction, and is used, for example, for fixing the wafer W in a vacuum chamber of a semiconductor manufacturing apparatus. The electrostatic chuck 100 includes a ceramic member 10 and a base member 20 arranged side by side in a predetermined arrangement direction (in the present embodiment, a vertical direction (Z-axis direction)). The ceramic member 10 and the base member 20 are arranged such that the lower surface S2 of the ceramic member 10 (see FIG. 2) and the upper surface S3 of the base member 20 face each other in the arrangement direction.

  The ceramic member 10 is a plate-like member having a substantially circular flat upper surface (hereinafter, referred to as an “adsorption surface”) S1 substantially orthogonal to the above-described arrangement direction (Z-axis direction), and is made of ceramics (for example, alumina or aluminum nitride). Etc.). The diameter of the ceramic member 10 is, for example, about 50 mm to 500 mm (generally, about 200 mm to 350 mm), and the thickness of the ceramic member 10 is, for example, about 1 mm to 10 mm. In this specification, a direction orthogonal to the Z-axis direction is referred to as a “surface direction”, and as shown in FIG. 3, a circumferential direction centered on the center point Px of the suction surface S1 in the surface direction is referred to as a “circumferential direction”. The direction perpendicular to the circumferential direction CD in the plane direction is referred to as a “radial direction RD”.

  As shown in FIG. 2, a chuck electrode 40 formed of a conductive material (for example, tungsten, molybdenum, platinum, or the like) is disposed inside the ceramic member 10. The shape of the chuck electrode 40 as viewed in the Z-axis direction is, for example, substantially circular. When a voltage is applied to the chuck electrode 40 from a power supply (not shown), an electrostatic attraction is generated, and the wafer W is suction-fixed to the suction surface S1 of the ceramic member 10 by the electrostatic attraction.

  Inside the ceramic member 10, a heater electrode layer 50 for controlling the temperature distribution of the suction surface S1 of the ceramic member 10 (ie, controlling the temperature distribution of the wafer W held on the suction surface S1), and a heater And a configuration for supplying power to the electrode layer 50. These configurations will be described later in detail. The chuck electrode 40 and the heater electrode layer 50 correspond to a conductive part in the claims.

  The base member 20 is, for example, a circular flat plate-shaped member having the same diameter as the ceramic member 10 or having a larger diameter than the ceramic member 10, and is formed of, for example, a metal (aluminum, an aluminum alloy, or the like). The diameter of the base member 20 is, for example, about 220 mm to 550 mm (normally, 220 mm to 350 mm), and the thickness of the base member 20 is, for example, about 20 mm to 40 mm.

  The base member 20 is joined to the ceramic member 10 by an adhesive layer 30 disposed between the lower surface S2 of the ceramic member 10 and the upper surface S3 of the base member 20. The adhesive layer 30 is made of, for example, an adhesive such as a silicone resin, an acrylic resin, or an epoxy resin. The thickness of the adhesive layer 30 is, for example, about 0.1 mm to 1 mm.

  A coolant channel 21 is formed inside the base member 20. When a coolant (for example, a fluorine-based inert liquid or water) flows through the coolant channel 21, the base member 20 is cooled and heat transfer between the base member 20 and the ceramic member 10 via the adhesive layer 30 ( The ceramic member 10 is cooled by the heat drawing, and the wafer W held on the suction surface S1 of the ceramic member 10 is cooled. Thereby, control of the temperature distribution of the wafer W is realized.

A-2. Configuration of heater electrode layer 50 and the like:
Next, the configuration of the heater electrode layer 50 and the configuration for supplying power to the heater electrode layer 50 will be described in detail.

  As described above, the electrostatic chuck 100 includes the heater electrode layer 50 (see FIG. 2). The heater electrode layer 50 is formed of a conductive material (for example, tungsten, molybdenum, platinum, or the like). In this embodiment, the heater electrode layer 50 is disposed below the chuck electrode 40.

  The heater electrode layer 50 includes a plurality of heater electrodes 500 (see FIG. 4). Here, as shown in FIG. 3, in the present embodiment, a plurality of virtual regions, ie, segments SE, are set in the ceramic member 10. More specifically, when viewed in the Z-axis direction, the ceramic member 10 is formed by a plurality of virtual annular regions (where the center is the center point Px of the suction surface S1) with a plurality of concentric first boundary lines BL1. Only the region including the point Px is divided into circular regions), and each annular region is a plurality of virtual regions arranged in the circumferential direction CD by the plurality of second boundary lines BL2 extending in the radial direction RD. It is divided into SE. Each of the plurality of heater electrodes 500 is arranged on one of the plurality of segments SE set on the ceramic member 10. That is, in the electrostatic chuck 100 of the present embodiment, one heater electrode 500 is arranged in each of the plurality of segments SE.

  FIG. 4 is an explanatory diagram schematically showing an XY cross-sectional configuration of one heater electrode 500 arranged in one segment SE. As shown in FIG. 4, the heater electrode 500 is a linear resistance heating element as viewed in the Z-axis direction. Hereinafter, one end of the heater electrode 500 is referred to as a first end 521, and the other end of the heater electrode 500 is referred to as a second end 522. The same applies to the configuration of the heater electrodes 500 arranged in other segments SE.

Further, as shown in FIG. 2, the electrostatic chuck 100 has a configuration for supplying power to each heater electrode 500 constituting the heater electrode layer 50. Specifically, the electrostatic chuck 100 includes the driver electrode layer 60. In this embodiment, the driver electrode layer 60 is disposed below the heater electrode layer 50. The driver electrode layer 60 is formed of a conductive material (for example, tungsten, molybdenum, platinum, or the like). The driver electrode layer 60 includes a plurality of pairs of driver electrodes 61 and 62 which are patterns having predetermined regions parallel to the plane direction (FIG. 2 shows only the pair of driver electrodes 61 and 62). Each of the driver electrodes 61 and 62 is different from the heater electrode 500 in that at least one of the following (1) and (2) is satisfied.
(1) The cross-sectional area of each of the driver electrodes 61 and 62 is 10 times or more the cross-sectional area of the heater electrode 500.
(2) In the plane direction, each of the driver electrodes 61 and 62 has an area larger than one segment SE.
The driver electrode layer 60 corresponds to a conductive part in the claims.

  All or some of the plurality of heater electrodes 500 constituting the heater electrode layer 50 are connected in parallel to a pair of driver electrodes 61 and 62 in the driver electrode layer 60. Specifically, as shown in FIGS. 2 and 4, a first end 521 of each heater electrode 500 is connected to a driver electrode layer 60 via a first heater-side via 721 formed of a conductive material. Are electrically connected to the first driver electrode 61, which is one of the pair of driver electrodes 61, 62, and the second end 522 of each heater electrode 500 is connected to a second heater-side via made of a conductive material. The second driver electrode 62, which is the other of the pair of driver electrodes 61, 62 in the driver electrode layer 60, is electrically connected via 722. A part of the plurality of heater electrodes 500 is electrically connected to a certain pair of driver electrodes 61 and 62, and the other part of the plurality of heater electrodes 500 is electrically connected to another pair of driver electrodes 61 and 62. ing.

  2, a plurality of pairs of terminal holes 110 and 120 extending from the lower surface S4 of the base member 20 to the inside of the ceramic member 10 are formed in the electrostatic chuck 100. (Only the terminal holes 110 and 120 are shown). Each of the terminal holes 110 and 120 includes a through hole 22 that vertically penetrates the base member 20, a through hole 32 that vertically penetrates the adhesive layer 30, and a concave portion 12 formed on the lower surface S <b> 2 side of the ceramic member 10. Are integral holes formed by communicating with each other.

  A first power supply terminal 741 having a columnar shape is accommodated in the first terminal hole 110 which is one of the pair of terminal holes 110 and 120. In addition, a first electrode pad 731 is provided on the bottom surface of the concave portion 12 of the ceramic member 10 constituting the first terminal hole 110. The first power supply terminal 741 is joined to the first electrode pad 731 by, for example, brazing or the like. Further, the first electrode pad 731 is electrically connected to the first driver electrode 61 via the first power supply side via 711. Similarly, the column-shaped second power supply terminal 742 is accommodated in the second terminal hole 120 which is the other of the pair of terminal holes 110 and 120. Further, a second electrode pad 732 is provided on the bottom surface of the concave portion 12 of the ceramic member 10 constituting the second terminal hole 120. The second power supply terminal 742 is joined to the second electrode pad 732 by, for example, brazing or the like. Further, the second electrode pad 732 is electrically connected to the second driver electrode 62 via the second power supply side via 712. The power supply terminals 741 and 742, the electrode pads 731 and 732, and the power supply side vias 711 and 712 are all formed of a conductive material.

  A pair of power supply terminals 741 and 742 accommodated in each of the plurality of pairs of terminal holes 110 and 120 are connected to a power supply (not shown). The voltage from the power supply is supplied to the pair of driver electrodes 61 and 62 via the pair of power supply terminals 741 and 742, the pair of electrode pads 731 and 732, and the pair of power supply side vias 711 and 712. The voltage is applied to the heater electrode 500 via a pair of heater-side vias 721 and 722 provided for the electrode 500. Thereby, each heater electrode 500 generates heat, and the segment SE on which the heater electrode 500 is arranged is heated. The temperature of each segment SE is individually controlled by individually controlling the voltage applied to the heater electrode 500 disposed on each segment SE of the ceramic member 10 and connected to a different pair of driver electrodes 61, 62 and the like. be able to. Thereby, control of the temperature distribution of the suction surface S1 of the ceramic member 10 (that is, control of the temperature distribution of the wafer W held on the suction surface S1) is realized. Hereinafter, the ceramic portion of the ceramic member 10 other than the portion formed of the conductive material (the chuck electrode 40, the heater electrode layer 50, the driver electrode layer 60, and the like) is referred to as a ceramic portion 950.

A-3. Surface configuration of conductive part:
FIG. 4 shows an enlarged cross-sectional configuration of a portion X1 of the heater electrode 500. As shown in part X1, the heater electrode 500 is configured to include particles M of a conductive material described later. Further, at least a part of the plurality of particles M located near the surface 501 of the heater electrode 500 has been cut, and the cut surface MD is exposed on the surface 501 of the heater electrode 500. The state in which the cut surface MD of the particle M is exposed on the surface of the heater electrode 500 is confirmed by, for example, an SEM image obtained by imaging a cross section including the surface 501 of the heater electrode 500 with a scanning electron microscope (SEM). can do. Similarly, the cut surfaces of the cut conductive material particles are exposed on the surfaces of the chuck electrode 40 and the driver electrode layer 60.

A-4. Manufacturing method of the electrostatic chuck 100:
FIG. 5 is a flowchart illustrating a method of manufacturing the electrostatic chuck 100, FIG. 6 is an explanatory diagram illustrating an outline of a punching process in the method of manufacturing the electrostatic chuck 100, and FIG. It is explanatory drawing which shows the outline | summary of the arrangement | positioning process of the semi-hardened conductive pattern in the method.

  As shown in FIG. 5, first, a semi-cured sheet 800 is prepared (S110). The semi-cured sheet 800 includes a conductive material serving as a conductor and a curable resin that is cured by at least one of heat and light, has conductivity at least after firing, and is a semi-cured sheet. . Here, the semi-cured (B stage) state refers to (1) a state in which it does not flow, stays in a rubber-like state without being melted even when it is further heated, and (2) does not flow. It is to satisfy both that it becomes possible to bond by heating after pressing. Next, a semi-cured conductive pattern 800A having a shape corresponding to each conductive portion is formed from the semi-cured sheet 800 (S120). The conductive portion is, for example, the above-described chuck electrode 40, heater electrode layer 50, and driver electrode layer 60. 6 and 7A illustrate a semi-cured conductive pattern 800A having a shape corresponding to the heater electrode 500 included in the heater electrode layer 50.

  Next, the semi-cured conductive pattern 800A is placed on a ceramic green sheet (hereinafter, referred to as a green sheet) 950A, and is cured by at least one of heat and light, so that the conductive part precursor adhered to the green sheet 950A. Is formed (S130). The conductive part precursor is a chuck electrode precursor that becomes the chuck electrode 40 by firing when the conductive part is the chuck electrode 40, and is fired by firing when the conductive part is the heater electrode layer 50 (heater electrode 500). In the case where the conductive portion is the driver electrode layer 60 (driver electrodes 61 and 62), the heater electrode precursor 500A becomes the driver electrode precursor 60 by firing. Note that FIG. 7B illustrates a heater electrode precursor 500A. Next, a plurality of green sheets 950A including the green sheet 950A to which the conductive part precursor is bonded are stacked and fired simultaneously (S140). Through the above steps, the above-described ceramic member 10 is formed. Hereinafter, each step will be described in detail.

A-4-1. Step of preparing the semi-cured sheet 800 (S110):
In the step of preparing the semi-cured sheet 800 (S110), the semi-cured sheet 800 is produced by, for example, the following method. First, a conductive paste containing a conductive material and a curable resin is formed by mixing a conductive material, ceramic powder, a curable resin, a curing agent, and a dispersant in a solvent, and dissolving and defoaming. Note that a curable resin and a curative may be added after a dispersion is prepared in advance by adding a dispersant and a solvent to the conductive material or the ceramic powder and stirring. For mixing the conductive material and the like, a well-known device including, for example, a stirring blade, a three-roller, or the like can be used. Next, each raw material of the conductive paste will be described in detail.

  The conductive material may be a material having conductivity, and is not limited to a metal, and may be, for example, a conductive ceramic. Examples of the metal include particles (or powder) of tungsten, molybdenum, platinum, silver, copper, or the like, or an alloy thereof. Further, the particle size of the metal is preferably 0.1 μm or more. Accordingly, the surface area of the entire metal contained in the conductor paste is smaller than in the case where the metal particle size is less than 0.1 μm, and therefore, an increase in resistance due to oxidation is suppressed. As a result, it is possible to suppress that the conductive portion formed in S140 does not have sufficient conductivity to exhibit the functions of the heater electrode 500 and the like. Further, the particle size of the metal is preferably 100 μm or less. This facilitates sintering of the metal in the firing step of S140 and reduces the specific surface area exposed to the air, as compared with the case where the particle size of the metal exceeds 100 μm. Is suppressed. Further, the particle diameter of the metal is more preferably 50 μm or less. This makes it possible to form a semi-cured sheet 800 having a high uniformity of thickness when forming the conductive paste into a sheet in S110, as compared to the case where the metal particle size exceeds 50 μm.

  The curable resin may be any resin that can be cured by at least one of heat and light. Examples of the curable resin include an epoxy resin, a phenol resin, an acrylic resin, an unsaturated polyester resin, and a polyurethane resin. The curable resin is particularly preferably an epoxy resin from the viewpoint of ease of preparation. This is because the epoxy resin has high solubility in a solvent or the resin itself is liquid and can be mixed with a conductive material or ceramic powder without using a solvent. Examples of the epoxy resin include a glycidyl ether type epoxy resin, a glycidyl ester type epoxy resin, and a glycidylamine type epoxy resin. More specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and brominated bisphenol A Type epoxy resin, brominated bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin and the like. The curable resin is preferably an aliphatic resin containing no element having an atomic number of 9 or more. This is because such an aliphatic resin is a resin which easily burns off in the firing step of S140 and has a low ash content. As the aliphatic resin, aliphatic glycidyl ethers having high solubility in water are particularly preferable.

  The curing agent may be any curing agent capable of curing the above curable resin. Like the curable resin, the curing agent is preferably a resin that is easily burned off in the firing step and has a low ash content. Specifically, an aliphatic resin containing no element having an atomic number of 9 or more is preferable. Examples of the curing agent for the epoxy resin include primary, secondary and tertiary amine compounds, modified polyamide compounds, imidazoles, polymercaptans, acid anhydrides, dicyandiamide and the like. As the modified polyamide compound, for example, a compound produced by a reaction between dimer acid and an aliphatic polyamine can be used. The properties of the modified polyamide-based curing agent are determined by the type of polyamine, the ratio of amine to dimer acid, and the amount of the third modifying component. The third modifying component is, for example, an epoxy resin, and by preliminarily reacting the epoxy resin, the compatibility of the modified polyamide with the epoxy resin is greatly improved. The curing agent is preferably an aliphatic polyamine-based curing agent having high solubility in water, and particularly preferably an aliphatic polyamine-based curing agent having an amine value of 100 or more and 200 or less.

  The ceramic powder is preferably the same as the ceramic powder contained in the green sheet 950A. Thereby, in the ceramic member 10 formed in the firing step of S140, the adhesion between the conductive portion formed from the conductive paste and the ceramic portion formed from the green sheet 950A can be improved.

  The dispersant is a component for controlling the dispersibility of the conductive material and the ceramic powder in the curable resin. Examples of dispersants include ionic and non-ionic dispersants. Examples of the ionic dispersant include polyacrylic acid, polycarboxylic acid, sodium salts and ammonium salts thereof, sulfonic acid copolymers and sodium and ammonium salts thereof. As the nonionic dispersant, polyethylene glycol, its ether and its ester can be used. As the dispersant for the ceramic powder, a polymer containing a carboxylic acid is preferable. This is because a polymer containing a carboxylic acid easily forms a hydrogen bond with a surface functional group of a powder of a conductive material or a ceramic powder, so that it is easily adsorbed, and a high dispersion effect can be obtained with a small amount.

  The solvent may be any solvent that imparts appropriate viscosity to the conductor paste and that can be easily volatilized by drying after forming the conductor paste into a sheet. Examples of the solvent include water and various organic solvents. However, in the case where a conductive paste having an appropriate viscosity can be obtained by using a liquid curable resin, a solvent is not necessarily required for producing the conductive paste. As the organic solvent, for example, alcohols such as isopropyl alcohol, ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate and isobutyl acetate, and aromatic hydrocarbons such as toluene and xylene can be used. The use of water as a solvent is particularly preferable from the viewpoint of working environment safety.

  After the formation of the conductive paste, the conductive paste is applied to the surface of a predetermined member in a sheet shape. For applying the conductive paste, for example, a known method such as a doctor blade, a knife coater, or a roll coater can be used. Next, the conductor paste applied in a sheet shape is semi-cured by at least one of heat and light. Specifically, the conductor paste on a predetermined member is loosely heated by a dryer, or is lightly exposed by an exposure machine. Thereby, the semi-cured sheet 800 can be manufactured. In addition, as a compounding example of the raw material of the semi-cured sheet 800 (conductor paste), the conductive material is 90 parts by weight of tungsten powder, the inorganic powder is 10 parts by weight of alumina powder, and the resin material (functions as a binder and a dispersant) is 7.2 parts by weight of a water-soluble epoxy resin (glycerol polyglycidyl ether), 1.2 parts by weight of a water-soluble curing agent (aliphatic polyamine), 0.5 parts by weight of a dispersant (modified polymer of carboxylic acid-containing polymer), , 20 parts by weight of water. The component that most affects the conductivity of the conductive portion (chuck electrode 40, heater electrode layer 50, driver electrode layer 60) is a conductive material (for example, tungsten powder). Therefore, the amount of the conductive material to be added is preferably 50 parts by weight or more. The reason is that when the amount of the conductive material is less than 50 parts by weight, the compounding ratio of the conductive material is too low, and the conductivity as the conductive part is reduced, or the wire is broken when forming a fine conductive part. This is because the possibility of doing so increases. Further, the amount of the conductive material added is preferably 150 parts by weight or less. The reason is that, when the amount of the conductive material added is more than 150 parts by weight, when the ceramic green sheet 950A and the conductive part precursor are simultaneously fired in the above-described firing step (S140), a difference in shrinkage between the two is considered. This is because defects such as cracks easily occur in the conductive portion and the like. Also, since the amount of the resin material relative to the conductive material is relatively small, the dispersibility of the conductive material is reduced, aggregates are easily generated, and it is difficult to form a fine and accurate conductive portion. is there.

A-4-2. Step of forming semi-cured conductive pattern 800A (S120):
In the step of forming the semi-cured conductive pattern 800A (S120), the semi-cured conductive pattern 800A is formed from the semi-cured sheet 800 by, for example, the following method. For example, as shown in FIG. 6A, a punching die 900 is prepared. The punching die 900 includes a punching punch 910 and a punching table 920. The punch for punching 910 is formed in a shape corresponding to the shape of one heater electrode 500, for example. The punching table 920 has an opening (not shown) having a shape corresponding to the shape of one heater electrode 500, for example. A plurality of semi-cured conductive patterns 800 </ b> A are arranged on the punching stand 920 in a superimposed manner. Next, as shown in FIG. 6B, when the punches 910 are passed through the punching table 920 from above the plurality of semi-cured conductive patterns 800A through the openings of the punching table 920, the punches 910 overlap each other. The plurality of semi-cured conductive patterns 800A thus obtained are punched into a shape corresponding to the shape of the heater electrode 500. Accordingly, a plurality of semi-cured conductive patterns 800A having the same shape can be formed at a time. When a large number of semi-cured conductive patterns (semi-cured conductive patterns 800A) having the same shape are formed, a method using a punching die is preferable. As another method for forming the semi-cured conductive pattern, for example, a method of cutting out the semi-cured conductive pattern 800A from the semi-cured sheet 800 using a cutting plotter can be mentioned. When a large number of semi-cured conductive patterns having different shapes are formed, a method using a cutting plotter is preferable. Further, by forming the conductive part precursor by punching or cutting out from the semi-cured conductive pattern in this manner, for example, as described above, the particles M of the conductive material located near the surface 501 of the heater electrode 500 are cut, As a result, the cut surface MD of the cut particles M is exposed on the front surface 501 of the heater electrode 500 (see X1 in FIG. 4). Thereby, for example, the line width of the heater electrode 500 can be made uniform.

A-4-3. Step of forming conductive part precursor (S130):
In the step of forming the conductive part precursor (for example, the heater electrode precursor 500A) (S130), first, a plurality of green sheets 950A mainly containing, for example, alumina are prepared. Then, a semi-cured conductive pattern 800A is attached to one of the green sheets 950A. Specifically, as shown in FIG. 7A, the first end 821A of the semi-cured conductive pattern 800A is disposed on the first heater-side via precursor 721A before firing, which is exposed on the green sheet 950A. Then, the second end portion 822A is disposed on the unheated second heater-side via precursor 722A exposed on the green sheet 950A. The method of attaching the semi-cured conductive pattern 800A to the green sheet 950A is not particularly limited. For example, the semi-cured conductive pattern 800A may be directly pressed to the green sheet 950A for pressure bonding. Further, when the semi-cured conductive pattern 800A is thin and is difficult to handle with the semi-cured conductive pattern 800A alone, the semi-cured conductive pattern 800A may be handled by pasting it on a transfer film such as a polyethylene terephthalate (PET) film. . In the present embodiment, the green sheet 950A may be formed of a forming material including a curable resin (gel cast molding). However, the green sheet containing the curable resin tends to be relatively hard, so that a crack may be generated in the green sheet when forming a through hole for the first heater-side via 721 and the like. In addition, when a relatively wide material such as a green sheet is subjected to gel casting, the amount of shrinkage upon curing is large, and thus, for example, the end of the green sheet is likely to be warped. Therefore, it is preferable that the green sheet 950A be formed not including the curable resin but including the thermoplastic binder.

  Next, the semi-cured conductive pattern 800A attached to the green sheet 950A is cured by at least one of heat and light. Specifically, the semi-cured conductive pattern 800A is heated by a dryer or exposed by an exposure machine. Thus, the heater electrode precursor 500A bonded to the green sheet 950A can be manufactured by the adhesive force of the semi-cured conductive pattern 800A (see FIG. 7B). The other green sheets 950A are subjected to necessary processing such as formation of through holes, filling of via ink, application of electrode ink for forming the chuck electrode 40, and the like. As the via ink and the electrode ink, for example, a metallized ink that is made into a slurry by mixing a tungsten powder with a green sheet raw material powder containing alumina as a main component is used.

A-4-4. Step of forming ceramic member 10 including heater electrode 500 and the like (S140):
In the step of forming the ceramic member 10 (S140), the green sheet 950A to which the conductive part precursor (heater electrode precursor 500A and the like) is adhered and another green sheet 950A are laminated and thermocompressed. Is cut into a predetermined shape and fired in a reducing atmosphere (for example, fired at 1400 to 1800 ° C.). By this baking treatment, the plurality of green sheets 950A and the conductive part precursor are simultaneously sintered, the green sheet 950A becomes the ceramic part 950, and the conductive part precursor becomes the conductive part (the heater electrode 500 and the like). Thereby, the ceramic member 10 is formed.

  Next, the base member 20 can be manufactured by a known method. Thereafter, the ceramic member 10 and the base member 20 are joined using an adhesive such as a silicone-based resin, an acrylic-based resin, or an epoxy-based resin (S150). Thus, the manufacture of the electrostatic chuck 100 having the above-described configuration is completed.

A-5. Effects of this embodiment:
For example, if an attempt is made to form a conductive pattern from a non-curable conductive paste that contains a conductive material and does not include a curable resin, the non-curable conductive paste has a low formality that maintains its shape, It is difficult to accurately form a shape (for example, a design shape) corresponding to the conductive portion. For example, even if an attempt is made to cut out a conductive pattern from a non-curable conductive paste, the pattern shape cannot be maintained, and the conductive pattern cannot be accurately formed in a shape corresponding to the conductive portion. Further, when the non-curable conductive paste is sandwiched and pressed between a plurality of green sheets to be laminated, the conductive paste is easily deformed by the pressing force. On the other hand, in the method of manufacturing the electrostatic chuck 100 according to the present embodiment, the semi-cured conductive pattern 800A is formed from the semi-cured sheet 800 in the semi-cured state. Since the semi-cured sheet 800 has a higher formability than the non-curable conductive paste, the semi-cured conductive pattern 800A has a conductive portion (such as the heater electrode 500) as compared with the case where the non-curable conductive paste is used. Can be accurately formed in a shape corresponding to

  Further, in the present embodiment, the semi-cured conductive pattern 800A is disposed on the green sheet 950A and cured by at least one of heat and light, so that the conductive part precursor (heater electrode precursor) adhered onto the green sheet 950A. Body 500A). Thereby, the handleability of the green sheet 950A on which the conductive part precursor is formed is improved. For example, when a plurality of green sheets 950A including the green sheet 950A to which the conductive part precursor is adhered are stacked, displacement of the position of the conductive part precursor on the green sheet 950A is suppressed.

  Here, as a method of forming a conductive pattern on a green sheet, for example, there is a method of forming a conductive paste by screen printing. However, in this method using screen printing, a fine pattern (for example, a line width of 50 μm or less) cannot be formed with high accuracy due to restrictions on the diameter of the mesh mask and the diameter of the conductive material. For example, when particles of the conductive material exist near the surface of the printed conductor paste, the particles may protrude from the surface of the conductor paste in a convex shape, and the line width of the conductor paste may vary. Further, in the method using screen printing, when the screen mask is removed after printing, irregularities may occur in the conductive paste, or irregularities in the mask wire diameter may be transferred, so that the thickness of the conductive paste may vary. On the other hand, as described above, in the present embodiment, first, the semiconductive sheet 800 is formed by forming the conductive paste into a sheet. Thus, a semi-cured sheet 800 having a substantially uniform thickness can be formed. Then, the heater electrode precursor 500A is formed on the green sheet 950A by arranging and curing the semi-cured conductive pattern 800A formed from the semi-cured sheet 800 on the green sheet 950A without using screen printing. Thereby, a semi-cured conductive pattern 800A having an accurate line width and thickness can be formed on the green sheet 950A, and as a result, a conductive portion in which variation in resistance value or the like is suppressed can be formed.

  Further, in the present embodiment, a plurality of semi-cured conductive patterns 800A having a shape corresponding to the conductive portion are collectively formed by stacking and punching a plurality of semi-cured sheets 800 (see FIG. 6). Thereby, compared to the case where the plurality of semi-cured conductive patterns 800A are individually formed, the sameness of the shapes of the plurality of semi-cured conductive patterns 800A (and, consequently, the plurality of conductive portions) is improved, and the number of manufacturing steps is reduced. be able to.

  In the present embodiment, a cut surface MD of the conductive material particles M is exposed on at least a part of the surface of the conductive portion (heater electrode 500) (see FIG. 4). As a result, the accuracy of the shape of the conductive portion is higher than in a configuration in which uncut particles of the conductive material protrude from the surface of the conductive portion in a convex shape, thereby suppressing variation in the thickness and width of the conductive portion. can do.

B. Modification:
The technology disclosed in the present specification is not limited to the above-described embodiment, and can be modified into various forms without departing from the gist thereof. For example, the following modifications are also possible.

  The method for manufacturing the electrostatic chuck 100 in the above embodiment is merely an example, and can be variously modified. For example, in the step of preparing the semi-cured sheet 800 (S110), the conductor paste may be formed without using at least one of the ceramic powder, the hardener, the dispersant, and the solvent. In addition, the particle size of the conductive material may be smaller than 0.1 μm, or may be larger than 100 μm.

  Further, in the above-described embodiment, as a method of forming the semi-cured conductive pattern 800A from the semi-cured sheet 800, a method by punching or cutting is exemplified. For example, by performing etching by exposure on the semi-cured sheet 800, The semi-cured conductive pattern 800A may be formed. However, in the etching by exposure, depending on the thickness of the semi-cured sheet 800, the calorific value may vary due to variation in the resistance value of the semi-cured conductive pattern 800A (heater electrode 500) after the etching. That is, in the etching by exposure, a difference occurs between the amount of exposure to the exposed surface of the semi-cured sheet 800 and the amount of exposure to the surface opposite to the exposed surface. There is a possibility that the degree of hardening differs between the opposite surface. Further, depending on the density of the semi-cured sheet 800, there is a possibility that a portion that is easily edged and a portion that is hardly edged may occur. As a result, the calorific value may vary in one heater electrode 500 or the calorific value may vary between a plurality of heater electrodes 500. Therefore, when the thickness of the semi-cured sheet 800 is relatively large, it is preferable to adopt the method of punching and cutting in the above embodiment.

  In the above-described embodiment, the semi-cured sheet 800 does not have to have conductivity, and may be at least conductive after firing.

  In the above-described embodiment, the chuck electrode 40, the heater electrode layer 50, and the driver electrode layer 60 have been illustrated as the conductive portions. Further, the conductive portion is not limited to the one disposed inside the ceramic member, but may be one disposed outside the ceramic member (such as a power supply pad or an external wiring).

  Further, in the above embodiment, each via may be configured by a single via, or may be configured by a group of a plurality of vias. In the above-described embodiment, each via may have a single-layer configuration including only a via portion, or a multi-layer configuration (for example, a configuration in which a via portion, a pad portion, and a via portion are stacked). Is also good.

  Further, the setting mode of the segment SE in the above embodiment can be arbitrarily changed. For example, in the above embodiment, the plurality of segments SE are set such that the segments SE are arranged in the circumferential direction CD of the suction surface S1, but the plurality of segments SE are set such that the segments SE are arranged in a lattice pattern. May be done. Also, for example, in the above embodiment, the entire electrostatic chuck 100 is virtually divided into a plurality of segments SE, but a part of the electrostatic chuck 100 may be virtually divided into a plurality of segments SE. Good. In the electrostatic chuck 100, the segment SE does not necessarily need to be set.

  Further, in the above embodiment, the monopolar system in which one chuck electrode 40 is provided inside the ceramic member 10 is adopted, but the bipolar system in which a pair of chuck electrodes 40 are provided inside the ceramic member 10 is used. May be employed. Further, the material forming each member in the electrostatic chuck 100 of the above embodiment is merely an example, and each member may be formed of another material.

  Further, the present invention is not limited to the electrostatic chuck 100 that includes the ceramic member 10 and the base member 20 and holds the wafer W using electrostatic attraction, but includes a ceramic member including a conductive portion (for example, CVD). The present invention is also applicable to a heater device such as a heater, a holding device such as a vacuum chuck, and a semiconductor manufacturing device component such as a shower head.

Reference Signs List 10: ceramic member 12: concave portion 20: base member 21: coolant channel 22: through hole 30: adhesive layer 32: through hole 40: chuck electrode 50: heater electrode layer 60: driver electrode layer 61: first driver electrode 62 : Second driver electrode 100: electrostatic chuck 110: first terminal hole 120: second terminal hole 500: heater electrode 500 A: heater electrode precursor 501: surface 521: first end 522: first 2 end 711: first power supply side via 712: second power supply side via 721: first heater side via 721A: first heater side via precursor 722: second heater side via 722A: second Heater-side via precursor 731: first electrode pad 732: second electrode pad 741: first power supply terminal 742: second power supply terminal 800: Cured sheet 800A: Semi-cured conductive pattern 821A: First end 822A: Second end 900: Punching die 910: Punch for punching 920: Punching table 950: Ceramic part 950A: Green sheet BL1: First boundary line BL2: Second boundary line CD: Circumferential direction M: Particle MD: Cut surface Px: Center point RD: Radial direction S1: Suction surface S2: Lower surface S3: Upper surface S4: Lower surface SE: Segment W: Wafer

Claims (2)

And the ceramic member for holding the object, and a conductive portion is a heater electrode layer disposed in the interior of the ceramic member, in the manufacturing method of an electrostatic chuck comprising a
Conductive material, and a curable resin that is cured by at least one of heat and light, including at least conductive after firing, and preparing a semi-cured sheet in a semi-cured state,
From the semi-cured sheet, a step of forming a semi-cured conductive pattern having a shape corresponding to the conductive portion,
The step of forming the conductive part precursor adhered on the ceramic green sheet, by arranging the semi-cured conductive pattern on a ceramic green sheet and curing by at least one of heat and light,
Including the ceramic green sheet to which the conductive part precursor is bonded, by stacking and firing a plurality of ceramic green sheets, forming the ceramic member having the conductive part;
including,
A method for manufacturing an electrostatic chuck , comprising: The method for manufacturing an electrostatic chuck according to claim 1,
The ceramic member includes a plurality of the conductive portions whose shapes are substantially the same,
In the step of forming the semi-cured conductive pattern, a plurality of semi-cured sheets are stacked and collectively subjected to a punching process to collectively form the plurality of semi-cured conductive patterns having a shape corresponding to the conductive portion.
A method for manufacturing an electrostatic chuck , comprising:

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