JP2012028539A - Ceramic joined body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic joined body with enhanced response after voltage removal and improved sealing effect of cooling gas or heating gas between an adsorption face and a semiconductor wafer.SOLUTION: A ceramic joined body comprises a joined body and a ceramic body made of ceramic. The ceramic body includes: a first surface bonded to the joined body; a second surface which is a rear face of the first surface; a through-hole which penetrates between the first surface and the second surface; and an electrode which is formed either on the first surface or inside the ceramic body. The second surface includes: a convex seal band portion which is formed continuously with the periphery of the ceramic body; an embossed pattern portion which is arranged inside the seal band portion, and which is a region provided with a plurality of protrusions having substantially the same height as that of the seal band portion; and a drop band portion which is a substantially planar region positioned between the seal band portion and the embossed pattern portion.

Description

  The present invention relates to a ceramic joined body.

  In a semiconductor manufacturing apparatus that performs etching, ion implantation, electron beam exposure, and the like, an electrostatic chuck is used for fixing, flattening, and conveying a semiconductor wafer. An electrostatic chuck is generally a ceramic joined body in which a ceramic body having electrodes is joined to a base having a substantially disk shape formed of, for example, aluminum. A semiconductor wafer is placed on the surface (adsorption surface) of the ceramic body of the electrostatic chuck, and a voltage is applied between the electrode and the semiconductor wafer, whereby the semiconductor wafer is adsorbed and fixed on the adsorption surface of the ceramic body. . Such an electrostatic chuck uses an inert gas such as helium to flow between the suction surface and the semiconductor wafer to cool the semiconductor wafer or to heat the semiconductor wafer in combination with a heater. In general, it is used in conjunction with the purpose of controlling the temperature.

  2. Description of the Related Art Conventionally, in an electrostatic chuck, a technique for forming a recess by shot blasting on a wafer installation surface (attracting surface) is known in order to shorten the residual time of the attracting force after voltage removal and improve responsiveness. (For example, patent document 1). However, in the case of a conventional electrostatic chuck having a cooling function and a heating function for a semiconductor wafer, there is a problem that the sealing effect of the cooling gas and the hot gas between the suction surface of the electrostatic chuck and the semiconductor wafer is low.

JP-A-4-304941 JP 2000-277594 A

  An object of this invention is to provide the ceramic joined body which improved the responsiveness after voltage removal, and the sealing effect of the cooling gas or hot gas between an adsorption surface and a semiconductor wafer.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A ceramic joined body,
To-be-joined,
A first surface formed of ceramics and bonded to the object to be bonded, a second surface that is a back surface of the first surface, and between the first surface and the second surface. A ceramic body having a through-hole penetrating through and an electrode formed on one of the first surface and the inside;
With
The second surface is
A convex seal band formed continuously on the outer edge of the ceramic body;
An embossed pattern portion which is an area where a plurality of convex portions having substantially the same height as the seal band portion are disposed inside the seal band portion,
A drop band portion that is a substantially planar region located between the seal band portion and the embossed pattern portion;
A ceramic joined body comprising:
With such a configuration, the second surface as the adsorption surface of the ceramic body has a convex seal band portion formed continuously with the outer edge, and is located inside the seal band portion, The embossing pattern part by which the some convex part which has substantially the same height as this part is arrange | positioned, a seal band part, and the substantially planar drop band part located between embossing pattern parts is provided. For this reason, when the ceramic joined body is used, the gas from the through hole can be sealed at the lower surface of the semiconductor wafer placed on the second surface and the inner corner of the seal band portion. Moreover, the residual time of the adsorption force after removing the voltage to the electrode can be shortened. As a result, it is possible to provide a ceramic joined body in which the responsiveness after voltage removal and the sealing effect of the cooling gas or the hot gas between the second surface and the semiconductor wafer are improved.

[Application Example 2]
A ceramic joined body according to Application Example 1,
At least some of the plurality of convex portions in the embossed pattern portion are arranged at equal intervals L between the centers of adjacent convex portions,
The ceramic bonded body, wherein a width of the drop band portion is 2L or more.
With such a configuration, at least a part of the plurality of convex portions in the embossed pattern portion is arranged at an interval L where the centers of the adjacent convex portions are equal to each other, and the width of the drop band portion is Since it is 2L or more, the sealing effect in the lower surface of the semiconductor wafer placed on the second surface and the inner corner of the seal band portion can be enhanced when the ceramic joined body is used.

[Application Example 3]
A ceramic joined body according to Application Example 1 or 2,
The height of the convex part of the seal band part and the embossed pattern part is 5 to 30 μm,
A ceramic bonded body in which the width of the drop band portion is larger than the width of the seal band portion.
With such a configuration, when the ceramic joined body is used, the sealing effect on the lower surface of the semiconductor wafer placed on the second surface and the inner corner of the seal band portion can be enhanced.

[Application Example 4]
The ceramic joined body according to any one of Application Examples 1 to 3,
The ceramic body is a ceramic joined body formed of alumina.

[Application Example 5]
The ceramic joined body according to any one of Application Examples 1 to 4,
The joined body is a ceramic joined body made of metal.

[Application Example 6]
The ceramic joined body according to any one of Application Examples 1 to 5,
The ceramic joined body is joined to the joined body by adhesion using a resin.
With such a configuration, since the ceramic body is bonded to the bonded body by adhesion using a resin, airtightness between the ceramic body and the bonded body can be ensured.

  The present invention can be realized in various modes, such as a ceramic joined body and a manufacturing method thereof, a ceramic joined body for a semiconductor manufacturing apparatus and a manufacturing method thereof, an electrostatic chuck and a manufacturing method thereof, and the like. It can be realized in the form. In addition, the present invention does not necessarily have all the various features described above, and may be configured by omitting some of them.

It is explanatory drawing which shows roughly the structure of the ceramic joined body (electrostatic chuck) in the Example of this invention. It is explanatory drawing which shows the structure of the plane of a ceramic body roughly. It is explanatory drawing which shows roughly the structure in the cross section of the edge part of a ceramic body. It is a flowchart which shows the schematic flow of the manufacturing method of an electrostatic chuck. It is explanatory drawing which shows roughly the mode of the cross section of the edge part at the time of use of an electrostatic chuck. It is explanatory drawing which shows roughly the mode of the cross section of the edge part at the time of use of the electrostatic chuck in a comparative example.

  Next, embodiments of the present invention will be described based on examples.

A. Example:
A-1. Schematic structure of ceramic joined body:
FIG. 1 is an explanatory diagram schematically showing a configuration of a ceramic joined body (electrostatic chuck) in an embodiment of the present invention. The ceramic joined body 100 of the present embodiment is used for fixing, flattening, and transporting a semiconductor wafer and cooling the semiconductor wafer in a semiconductor manufacturing apparatus that performs etching, ion implantation, electron beam exposure, and the like. Used as an electrostatic chuck. Hereinafter, the ceramic bonded body is also referred to as an “electrostatic chuck”.

  FIG. 1A is a plan view of the electrostatic chuck 100. FIG. 1B is a cross-sectional view of the electrostatic chuck 100. As shown in FIGS. 1A and 1B, the electrostatic chuck 100 includes a ceramic body 200 formed of ceramics and a base 300 joined to the ceramic body 200.

  The ceramic body 200 has a surface facing the base 300 (hereinafter also referred to as “first surface” or “bonding surface”) formed on a substantially planar surface of the base 300 and the bonding layer 400. It is joined. The bonding layer 400 is preferably formed by adhesion using a resin (for example, an epoxy resin adhesive, an acrylic resin adhesive, or a silicone adhesive). As shown in FIG. 1B, the semiconductor wafer W is placed on the back surface (hereinafter also referred to as “second surface” or “adsorption surface”) of the bonding surface of the ceramic body 200.

  The ceramic body 200 is a sintered body having a multilayer structure formed of ceramics such as alumina, calcium titanate, barium titanate, yttria, and aluminum nitride. The ceramic body 200 has a substantially disk shape, a diameter Dc of about 300 mm (about 12 inches), and a thickness tc of about 2 mm to about 5 mm. Inside the ceramic body 200, a plurality of electrodes 210 as conductors are embedded. An electrostatic force is generated by applying a voltage to the electrode 210 in a state where the semiconductor wafer W is placed, and the semiconductor wafer W can be sucked and fixed on the suction surface. The electrode 210 may be formed on the bonding surface of the ceramic body 200.

  In addition, a gas flow path 220 that is a through-hole penetrating between the bonding surface and the adsorption surface of the ceramic body 200 is provided inside the ceramic body 200. The gas flow path 220 is a hole for supplying an inert gas (for example, helium gas) for cooling the semiconductor wafer W supplied from a gas supply hole 320 (details will be described later) onto the adsorption surface. . Note that the gas flow path 220 may be a through-hole penetrating between the bonding surface and the adsorption surface of the ceramic body 200. However, in order to uniformly supply the inert gas to the adsorption surface, it is preferable to have a form having a plurality of jet outlets on the adsorption surface as shown in FIG.

  The base 300 as a joined body is made of a metal such as aluminum or stainless steel. The base 300 has a substantially disk shape, and its thickness ta is about 30 mm. Although the diameter of the base 300 can be arbitrarily set, in this embodiment, the diameter is slightly larger than the diameter Dc of the ceramic body 200. A gas supply hole 320 is formed inside the base 300 so as to penetrate the thickness direction thereof. The inert gas is supplied to the gas flow path 220 of the ceramic body 200 through the gas supply hole 320 by a device such as a pump.

A-2. Composition of ceramic body:
FIG. 2 is an explanatory diagram schematically showing a planar configuration of the ceramic body 200. FIG. 3 is an explanatory view schematically showing a configuration in a cross section of an end portion of the ceramic body 200. It is. As shown in FIG. 2, an embossed pattern portion 202, a drop band portion 204, and a seal band portion 206 are formed on the adsorption surface of the ceramic body 200.

  As shown in FIG. 3, the seal band portion 206 is a convex portion that is continuously formed in an annular shape on the outer edge of the ceramic body 200. The width Oc of the seal band portion 206 in this embodiment is about 8 mm. The protruding height Hc of the convex portion of the seal band portion is about 15 μm.

  The embossed pattern portion 202 is a region inside the seal band portion 206. In the embossed pattern portion 202, a plurality of convex portions having substantially the same protruding height as the seal band portion 206 are arranged. In the present embodiment, the shape of the convex portion arranged in the embossed pattern portion 202 is a cylindrical shape having a diameter Wc of about 2.5 mm. Moreover, the convex part arrange | positioned at the embossed pattern part 202 is arrange | positioned so that the center of adjacent convex parts may mutually have the space | interval L (this example about 5 mm). Here, the “center of the convex portion” means the symmetrical center of the figure forming the upper surface (that is, the suction surface side) of the convex portion. The protrusion height Hc of the convex portion arranged in the embossed pattern portion 202 is about 15 μm. In addition, the convex part arrange | positioned at the embossing pattern part 202 should just be arrange | positioned so that at least one part of several convex parts may mutually have the space | interval L which is equal. Therefore, for example, in order to provide the gas flow path 220, it is possible to move the positions of some of the convex portions or to omit some of the convex portions.

  The drop band portion 204 is formed between the seal band portion 206 and the embossed pattern portion 202 so as to be positioned in a band shape. The drop band portion 204 is a substantially planar region where no convex portion is formed. In this embodiment, the width Ic of the drop band portion 204 is about 10 mm. As described above, in the ceramic body 200 according to the present embodiment, the width Ic (about 10 mm) of the drop band portion 204 is larger than the width Oc (about 8 mm) of the seal band portion 206.

A-3. Manufacturing method of ceramic joined body:
FIG. 4 is a flowchart showing a schematic flow of a method for manufacturing the electrostatic chuck 100. First, the pattern of the electrode 210 (FIG. 1) is printed on the 1st green sheet which has an alumina powder as a main component by the screen-printing method using metallized ink (step S100). Next, a groove-like gas flow path 220 (FIG. 1) is formed by machining on the second green sheet containing alumina powder as a main component (step S110).

  Next, a green sheet mainly composed of alumina powder (third green sheet), a first green sheet, a second green sheet, and a green sheet mainly composed of alumina powder (fourth green sheet). Through holes are formed, and through holes are formed by machining or die cutting (step S120). The green sheet laminate produced in step S120 is thermocompression bonded, cut into a predetermined disk shape, and the cut sheet is fired in a reducing atmosphere. After firing, polishing is performed to a predetermined size (step S130). Next, nickel plating is applied to the terminal portion, and the base of the ceramic body 200 (FIGS. 2 and 3) is formed by brazing or soldering the terminal (step S140).

  Next, the embossed pattern portion 202, the drop band portion 204, and the seal band portion 206 are formed by blasting on the surface (that is, the bonding surface) side of the third green sheet of the base of the ceramic body 200 (step) S150). Finally, the base 300 and the ceramic body 200 are joined using a resin (step S160). The electrostatic chuck 100 is manufactured through the above steps.

  FIG. 5 is an explanatory view schematically showing the state of the cross section of the end portion when the electrostatic chuck 100 is used. In the electrostatic chuck 100 according to the present embodiment, when a voltage is applied to the electrode 210 in a state where the semiconductor wafer W is placed on the suction surface, an electrostatic suction force is generated between the suction surface and the semiconductor wafer W. As a result, the semiconductor wafer W is attracted in the suction surface direction DS (indicated by a white arrow) and is bent at the top of the drop band portion 204. As the semiconductor wafer W bends, the lower surface of the semiconductor wafer W is pressed against the corner portion CN located inside the seal band portion 206. For this reason, the inert gas C as the cooling gas ejected from the gas flow path 220 can be sealed at the corner portion CN. By sealing the cooling gas at the corner portion CN, the distribution of the cooling gas between the suction surface of the electrostatic chuck 100 and the semiconductor wafer W becomes uniform, and the cooling effect of the electrostatic chuck 100 becomes uniform. can do. Therefore, the electrostatic chuck 100 in the present embodiment can hold the semiconductor wafer W while keeping the temperature distribution of the semiconductor wafer W uniform.

  Further, the electrostatic chuck 100 according to the present embodiment has an effect of shortening the remaining time of the attracting force after the voltage is removed from the electrode 210 by arranging a plurality of convex portions on the embossed pattern portion 202. As a result, it is possible to provide an electrostatic chuck with improved responsiveness after voltage removal and a cooling gas sealing effect between the suction surface and the semiconductor wafer.

  In order to enhance the sealing effect between the lower surface of the semiconductor wafer W and the corner portion CN located inside the seal band portion 206, at least some of the plurality of convex portions in the embossed pattern portion 202 are adjacent to each other. The centers of the convex portions to be fitted are arranged at the same interval L (FIG. 3), and the width Ic (FIG. 3) of the drop band portion 204 is 2L or more with respect to the interval L between the centers of the adjacent convex portions. It is preferable that Moreover, it is preferable that both the protrusion height Hc of the convex part of the seal band part 206 and the protrusion height Hc of the convex part arrange | positioned at an embossing pattern part are in the range of 5 micrometers-30 micrometers.

  In addition, even if it is a case where it is a structure provided with the resistance heating element for heaters in the inside of a ceramic body, a hot gas can be sealed in the corner | angular part CN similarly to the case of the said cooling gas. For this reason, it becomes possible to provide the electrostatic chuck which improved the responsiveness after voltage removal, and the sealing effect of the hot gas between an adsorption surface and a semiconductor wafer.

  Further, in the electrostatic chuck 100 in the above embodiment, since the ceramic body 200 and the base 300 are bonded via the bonding layer 400 made of resin, the airtightness between the ceramic body 200 and the base 300 is improved. Can be secured.

B. Comparative example:
FIG. 6 is an explanatory view schematically showing the state of the cross section of the end portion when the electrostatic chuck 100a in the comparative example is used. The only difference from the above embodiment shown in FIG. 3 is that the ceramic body 200a does not include the drop band portion 204, and the other configuration is the same as that of the above embodiment.

  As shown in FIG. 6, in the electrostatic chuck 100a in the comparative example, a voltage is applied to the electrode 210 in a state where the semiconductor wafer W is placed on the suction surface, and the semiconductor wafer W is in the suction surface direction DS (white arrow). The semiconductor wafer W does not bend even if it is attracted to. For this reason, the inert gas C as a cooling gas ejected from the gas flow path 220 flows out between the adsorption surface and the bottom surface of the semiconductor wafer W and flows out to the external OS. Then, the electrostatic chuck 100a in the comparative example cannot keep the distribution of the cooling gas between the attracting surface and the semiconductor wafer W uniform. As a result, the temperature distribution of the semiconductor wafer W can be kept uniform. It becomes difficult.

  Further, in the comparative example, by smoothly forming the upper surface (suction surface side) of the seal band portion 206, the gap between the suction surface and the bottom surface of the semiconductor wafer W is reduced, and the inert gas C flows out to the external OS. It is also possible to suppress this (that is, to improve the cooling gas sealing effect). However, even in this case, as the electrostatic chuck 100a continues to be used, due to atmospheric gas, plasma, and the like during the processing process of the semiconductor wafer, the upper surface of the smoothly formed seal band 206 is gradually increased. Unevenness is formed on the surface. Then, similarly to the above, the gap between the adsorption surface and the bottom surface of the semiconductor wafer W becomes large, the inert gas C flows out to the external OS, and it becomes difficult to keep the temperature distribution of the semiconductor wafer W uniform. .

C. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

C1. Modification 1:
In the above embodiment, the configuration of the electrostatic chuck is illustrated. However, the embodiment shown in the above embodiment is merely an example, and various modifications can be made without departing from the gist of the present invention. Specifically, for example, the present invention can be used as a so-called monopolar type or bipolar type electrostatic chuck.

  In the above embodiment, the ceramic body and the base are bonded via a bonding layer formed by bonding, but are bonded by other methods (for example, mechanical bonding by mechanical clamping or screwing). It may be a thing.

  In the above embodiment, the base is formed using metal, but the base may be formed of other materials such as ceramics or resin. When the base is formed of a metal, it is preferable in that the bonding surface with the ceramic body can be easily formed into a shape close to a true plane. Further, the base may have a flow path for circulating cooling water formed therein.

  Further, the shapes and dimensions of the ceramic body and the base in the above embodiment are merely examples, and the shapes and dimensions (thickness, diameter, etc.) of the ceramic body and the base can be variously modified. For example, in the above embodiment, the ceramic body and the base have a substantially disk shape, but the ceramic body and the base may have other shapes (for example, a rectangular flat plate shape).

C2. Modification 2:
In the said Example, it illustrated about the structure of the ceramic body which comprises an electrostatic chuck. However, the embodiment shown in the above embodiment is merely an example, and various modifications can be made without departing from the gist of the present invention. Specifically, for example, a resistance heating element for a heater may be provided inside the ceramic body as a conductor in addition to the electrode.

  Moreover, in the said Example, the arrangement | positioning and shape of the convex part in the embossing pattern part of a ceramic body were illustrated and demonstrated. However, the arrangement and shape of the protrusions in the embossed pattern portion can be arbitrarily determined. For example, the arrangement of the convex portions may be a radial shape or a spiral shape. As for the shape of the convex portion, any shape such as a quadrangular prism shape can be adopted.

  Further, in the above-described embodiment, the “center of the convex portion” arranged in the embossed pattern portion means the symmetrical center of the figure forming the upper surface (that is, the suction surface side) of the convex portion, The center of the convex portion can be determined by other methods. For example, the center of the convex portion may be the center of gravity of the convex portion.

  Moreover, although the ceramic body in the said Example shall be provided with a seal band part, a drop band part, and an embossed pattern part, among these, an embossed pattern part can also be abbreviate | omitted. However, from the viewpoint of improving the responsiveness after voltage removal, it is preferable not to omit the embossed pattern portion.

  In addition, the shape and dimensions of the seal band portion, drop band portion, and embossed pattern portion of the ceramic body in the above embodiment are merely examples, and these shapes and dimensions (the width and protrusion height of each portion) are variously modified. Is possible.

100 ... Ceramic bonded body (electrostatic chuck)
DESCRIPTION OF SYMBOLS 100a ... Electrostatic chuck 200 ... Ceramic body 200a ... Ceramic body 202 ... Embossed pattern part 204 ... Drop band part 206 ... Seal band part 210 ... Electrode 220 ... Gas flow path 300 ... Base 320 ... Gas supply hole 400 ... Bonding layer W ... Semiconductor wafer C ... Inert gas CN ... Corner part DS ... Adsorption surface direction

Claims (6)

A ceramic joined body,
To-be-joined,
A first surface formed of ceramics and bonded to the object to be bonded, a second surface that is a back surface of the first surface, and between the first surface and the second surface. A ceramic body having a through-hole penetrating through and an electrode formed on one of the first surface and the inside;
With
The second surface is
A convex seal band formed continuously on the outer edge of the ceramic body;
An embossed pattern portion which is an area where a plurality of convex portions having substantially the same height as the seal band portion are disposed inside the seal band portion,
A drop band portion that is a substantially planar region located between the seal band portion and the embossed pattern portion;
A ceramic joined body comprising: The ceramic joined body according to claim 1,
At least some of the plurality of convex portions in the embossed pattern portion are arranged at equal intervals L between the centers of adjacent convex portions,
The ceramic bonded body, wherein a width of the drop band portion is 2L or more. The ceramic joined body according to claim 1 or 2,
The height of the seal band part and the convex part of the embossed pattern part is 5 to 30 μm,
A ceramic bonded body in which the width of the drop band portion is larger than the width of the seal band portion. A ceramic joined body according to any one of claims 1 to 3,
The ceramic body is a ceramic joined body formed of alumina. The ceramic joined body according to any one of claims 1 to 4,
The joined body is a ceramic joined body made of metal. A ceramic joined body according to any one of claims 1 to 5,
The ceramic joined body is joined to the joined body by adhesion using a resin.

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