JP2021118324A - Electrostatic chuck, electrostatic chuck device, and manufacturing method of electrostatic chuck - Google Patents

Abstract

To provide an electrostatic chuck in which deterioration of characteristics is suppressed.SOLUTION: An electrostatic chuck 20 includes a mounting plate 21, a support plate 22, and an intermediate bonding layer 23. The intermediate bonding layer 23 has an adsorption electrode 24 and an insulating layer 25. The intermediate bonding layer 23 is obtained by bonding the mounting plate 21 and the support plate 22 by sintering, and the adsorption electrode 24 is formed by firing a conductive film arranged on the upper surface of a second substrate to be the support plate 22. The insulating layer 25 is formed by sintering the insulating film arranged on the upper surface of the second substrate to be the support plate 22. For the conductive film and the insulating film, when the average thickness (μm) of the conductive film is Ct, and the solid content ratio (vol%) of the conductive film is Cv, the average thickness of the insulating film is It, the solid content ratio (vol%) of the insulating film is Iv, the average thicknesses It and Ct, and the solid content ratios Iv and Cv satisfy 0.6≤(It×Iv/100)/(Ct×Cv/100)≤0.9, It>Ct.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an electrostatic chuck, an electrostatic chuck device, and a method for manufacturing an electrostatic chuck.

Conventionally, an electrostatic chuck for fixing a wafer by utilizing electrostatic force is provided in a process chamber of a semiconductor manufacturing apparatus. In the electrostatic chuck, the suction plate for fixing the wafer includes an electrode for suction inside (see, for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 6-291175 Japanese Unexamined Patent Publication No. 9-82788

By the way, the electrodes included in the adsorption plate are formed by sintering a conductive paste or slurry. In the manufacturing process of this suction plate, cracks may occur in the suction plate. The cracks generated in the suction plate cause deterioration of the characteristics of the electrostatic chuck.

An object of the present disclosure is to provide an electrostatic chuck, an electrostatic chuck device, and a method for manufacturing an electrostatic chuck in which deterioration of characteristics is suppressed.

The electrostatic chuck according to one aspect of the present disclosure is an electrostatic chuck that fixes a work substrate by an electrostatic force, and includes a mounting plate on which the work substrate is mounted and a support plate that supports the above-mentioned mounting plate. An intermediate bonding layer, which is arranged between the above-mentioned mounting plate and the supporting plate and joins the previously described mounting plate and the supporting plate, is provided, and the intermediate joining layer is an internal region of the previously described mounting plate. The intermediate bonding layer has an adsorption electrode for generating an electrostatic force for adsorbing the work substrate to the above-mentioned mounting plate, and an insulating layer arranged so as to surround the adsorption electrode. The above-mentioned mounting plate and the support plate are joined by sintering, the adsorption electrode is formed by sintering a conductive film arranged on the upper surface of the support plate, and the insulating layer is the said. It is formed by sintering an insulating film arranged on the upper surface of the support plate, and the average thickness (μm) of the conductive film is Ct, the solid content ratio (vol%) of the conductive film is Cv, and the insulating film is formed. When the average thickness (μm) is It and the solid content ratio (vol%) of the insulating film is Iv, the average thickness It, Ct and the solid content ratio Iv, Cv are
0.6 ≤ (It x Iv ÷ 100) ÷ (Ct x Cv ÷ 100) ≤ 0.9
It> Ct
Meet.

In the above electrostatic chuck, the thickness of the conductive film and the insulating film is 50 μm or more and 150 μm or less, and the thickness of the adsorption electrode and the insulating layer is 10 μm or more and 50 μm or less. The difference from the thickness of the insulating layer is preferably ± 5 μm or less.

In the above electrostatic chuck, the solid content ratio of the insulating film is 15 vol% or more and 35 vol% or less in volume fraction, and the solid content ratio of the conductive film is 25 vol% or more and 45 vol% or less in volume fraction. Is preferable.

In the above electrostatic chuck, the insulating film is _{composed of a material containing Al 2} O ₃ as a main component, and the conductive film is made of a material _{containing a mixture of Al 2} O ₃ and a carbide or a refractory metal as a main component. It is preferably configured.

In the above electrostatic chuck, the mounting plate is a polycrystalline _Al 2 _O 3, AlN, and any one of the constituent material of the single crystal _Al 2 _{O 3,} the support plate, the polycrystalline _Al 2 _{O 3} , AlN, and single crystal Al ₂ O ₃ are preferably used as the constituent materials.

The electrostatic chuck device of the present disclosure includes the above-mentioned electrostatic chuck, a support base having a flow path through which a refrigerant flows and cooling the electrostatic chuck, and a bonding agent for joining the electrostatic chuck to the support base. Has.

The electrostatic chuck device of the present disclosure includes the above-mentioned electrostatic chuck and a support base for cooling the electrostatic chuck having a flow path through which a refrigerant flows, and the electrostatic chuck is directly connected to the support base. It is joined.

The method for manufacturing an electrostatic chuck of the present disclosure is a method for manufacturing an electrostatic chuck that fixes a work substrate by an electrostatic force. A step of forming a conductive film and an insulating film by arranging a conductive paste and an insulating paste on the upper surface of a second substrate which has a supporting plate for supporting the mounting plate and serves as the supporting plate. A first substrate to be the above-mentioned mounting plate is placed on the conductive film and the insulating film, pressure-stained to bond the first substrate and the second substrate to each other, and the conductive film is formed. The step of forming an adsorption electrode with the above and forming an insulating layer with the insulating film, the average thickness (μm) of the conductive film is Ct, and the solid content ratio (vol%) of the conductive film is Cv. When the average thickness (μm) of the insulating film is It and the solid content ratio (vol%) of the insulating film is Iv, the average thickness It, Ct and the solid content ratio Iv, Cv are
0.6 ≤ (It x Iv ÷ 100) ÷ (Ct x Cv ÷ 100) ≤ 0.9
It> Ct
Meet.

According to the electrostatic chuck, the electrostatic chuck device, and the method for manufacturing the electrostatic chuck, which is one aspect of the present disclosure, deterioration of characteristics can be suppressed.

FIG. 5 is a cross-sectional view showing an electrostatic chuck device of one embodiment. The schematic plan view which shows the electrostatic chuck of one Embodiment. FIG. 3 is a partial cross-sectional view of the electrostatic chuck of one embodiment. It is a partial cross-sectional view which shows the electrostatic chuck before joining, and is the partial cross-sectional view which shows a conductive film and an insulating film. The cross-sectional view which shows the manufacturing process of the electrostatic chuck of one Embodiment. The cross-sectional view which shows the manufacturing process of the electrostatic chuck of one Embodiment. The cross-sectional view which shows the manufacturing process of the electrostatic chuck of one Embodiment. The cross-sectional view which shows the manufacturing process of the electrostatic chuck of one Embodiment. The cross-sectional view which shows the manufacturing process of the electrostatic chuck of one Embodiment. The cross-sectional view which shows the manufacturing process of the electrostatic chuck of one Embodiment. The cross-sectional view which shows the manufacturing process of the electrostatic chuck of one Embodiment. The cross-sectional view which shows the manufacturing process of the electrostatic chuck of one Embodiment. Explanatory drawing explaining measurement of a conductive layer and an insulating layer. Explanatory drawing explaining measurement of a conductive layer and an insulating layer. FIG. 5 is a cross-sectional view showing an electrostatic chuck device of a modified example. FIG. 5 is a cross-sectional view showing an electrostatic chuck device of a comparative example.

Hereinafter, one embodiment will be described.
In the attached drawings, the components may be enlarged for easy understanding. The dimensional ratios of the components may differ from the actual ones or those in another drawing. Further, in the cross-sectional view, hatching of some components may be omitted for easy understanding.

The electrostatic chuck device 10 shown in FIG. 1 attracts and holds the work substrate W by utilizing electrostatic force. The work substrate W is, for example, a semiconductor wafer. The electrostatic chuck device 10 is provided in a substrate processing device that processes the work substrate W. The substrate processing apparatus, for example, generates plasma to process the work substrate W.

The electrostatic chuck device 10 of the present embodiment has an electrostatic chuck (ESC: electrostatic chuck) 20, a bonding agent 30, and a support base 40.
As shown in FIG. 2, the electrostatic chuck 20 has a substantially circular shape in a plan view. The electrostatic chuck 20 includes a mounting plate 21, a support plate 22, and an intermediate bonding layer 23. In FIG. 2, the mounting plate 21 is transparently shown. The mounting plate 21 and the support plate 22 have a substantially circular shape in a plan view. Planar view refers to viewing an object from a direction perpendicular to the upper surface 21a of the mounting plate 21 shown in FIG.

In this embodiment, the mounting plate 21 is a sapphire substrate. The sapphire substrate is a single crystal material (single crystal Al ₂ O ₃ ) of _{aluminum oxide (Al 2} O _3). The sapphire substrate has no grain boundaries and has excellent plasma resistance. The sapphire substrate constituting the mounting plate 21 is configured such that a predetermined surface in the crystal orientation, for example, the c surface is the upper surface 21a. It should be noted that the surface a may be configured to be the upper surface 21a. The coefficient of thermal expansion of the mounting plate 21, which is a sapphire substrate, is 7.7 × ^10-6 / K (every Kelvin) in the range of 400 ° C. or lower. The volume resistance value of the sapphire substrate is 1.0 × 10 ¹⁴ Ω · cm or more. The thickness of the mounting plate 21 is preferably 0.3 mm or more and 0.5 mm or less. As the mounting plate 21, for example, an alumina ceramic (polycrystalline Al ₂ O ₃ ) substrate, an aluminum nitride (AlN) substrate, or the like can be used.

As shown in FIG. 2, the support plate 22 has, for example, a circular shape in a plan view. As shown in FIG. 1, the support plate 22 has a through hole 22x that penetrates the support plate 22 in the thickness direction. A feeding electrode 26 is provided in the through hole 22x. The feeding electrode 26 is electrically connected to the suction electrode 24. As the support plate 22, for example, an alumina ceramic (Al ₂ O ₃ ) substrate can be used. The coefficient of thermal expansion of the support plate 22 is 7.2 × ^10-6 / K in the range of 400 ° C. or lower. The volume resistance value of _{Al 2} O ₃ constituting the support plate 22 ^{is 1.0 × 10 14} Ω · cm or more. As the material of the feeding electrode 26, for example, the same material as the adsorption electrode 24 described above can be used. As the support plate 22, for example, a sapphire substrate, an AlN substrate, or the like can be used. When a sapphire substrate is used as the support plate 22, it is preferable to use a sapphire substrate configured so that the same surface as the surface according to the crystal orientation of the mounting plate 21 is the upper surface.

As shown in FIGS. 1 and 2, the intermediate bonding layer 23 includes an adsorption electrode 24 and an insulating layer 25. As shown in FIG. 1, the suction electrode 24 is provided between the mounting plate 21 and the support plate 22. In the present embodiment, the suction electrode 24 has a substantially circular shape in a plan view. The adsorption electrode 24 can be formed in a predetermined pattern. Further, a plurality of adsorption electrodes 24 may be provided depending on the adsorption method.

The adsorption electrode 24 is a _{composite ceramic containing aluminum oxide (Al 2} O ₃ ) and a conductive material. The conductive material is a carbide or a refractory metal. That is, the adsorption electrode 24 is _{mainly composed of a mixture of Al 2} O ₃ and a carbide or a refractory metal. As the carbide, for example, an alumina titanium carbide material (AlTiC material) can be used. The AlTiC material is obtained by dispersing titanium carbide (TiC) in _{Al 2} O _{3 and performing reaction sintering.} The coefficient of thermal expansion of the AlTiC material is 7.4 × ^10-6 / K in the range of 400 ° C. or lower. The volume resistance value of the AlTiC material is 1.0 × 10 ^-3 Ω · cm, and the resistance change rate is 20% or less in the range of −200 ° C. or higher and 400 ° C. or lower. As the oxide-based eutectic point material, for example, yttrium oxide (Y ₂ O ₃ ), ytterbium oxide (Yb ₂ O ₃ ) and the like can be used. As the refractory metal, for example, tungsten (W), tantalum (Ta), molybdenum (Mo) and the like can be used. In the present embodiment, the adsorption electrode 24 is _{formed by using the conductive paste containing the above-mentioned Al 2} O ₃ powder, AlTiC powder, and screen oil.

The insulating layer 25 is provided between the mounting plate 21 and the support plate 22 and around the suction electrode 24. In the present embodiment, the insulating layer 25 is substantially annular in a plan view. When a predetermined pattern or a plurality of adsorption electrodes 24 are provided, the insulating layer 25 is provided so as to separate them. The insulating layer 25 is provided at least along the peripheral edge of the mounting plate 21. The insulating layer 25 is mainly composed of _{Al 2} O _3. The insulating layer 25 is _{formed by using the insulating paste containing the above-mentioned Al 2} O ₃ powder, screen oil, and resin component.

As shown in FIG. 3, the thickness T24 of the adsorption electrode 24 is 10 μm or more and 50 μm or less. The thickness T25 of the insulating layer 25 is 10 μm or more and 50 μm or less. The difference between the thickness T24 of the suction electrode 24 and the thickness T25 of the insulating layer 25 is 10% or less of the thickness of the thickness T24 of the suction electrode 24 and the thickness T25 of the insulating layer 25. For example, when the thickness T24 of the suction electrode 24 is 10 μm, the difference between the thickness T24 of the suction electrode 24 and the thickness T25 of the insulating layer 25 is ± 1 μm or less. When the thickness T24 of the adsorption electrode 24 or the thickness T25 of the insulating layer 25 is 50 μm, the difference ΔT between the thickness T24 of the adsorption electrode 24 and the thickness T25 of the insulating layer 25 is ± 5 μm or less. The distance between the outer surface 24c of the suction electrode 24 and the inner surface 25d of the insulating layer 25 is, for example, 100 μm.

When the difference ΔT between the thickness T24 of the suction electrode 24 and the thickness T25 of the insulating layer 25 is larger than ± 5 μm, cracks are likely to occur in at least one of the mounting plate 21 and the support plate 22. The adsorption electrode 24 and the insulating layer 25 are formed by pressure sintering the conductive paste and the insulating paste. Therefore, after sintering, that is, after the mounting plate 21 and the support plate 22 are bonded by the intermediate bonding layer 23, if the difference ΔT between the thickness T24 of the adsorption electrode 24 and the thickness T25 of the insulating layer 25 is large, The strain generated in at least one of the mounting plate 21 and the support plate 22 causes a crack in at least one of the mounting plate 21 and the support plate 22.

Such an adsorption electrode 24 and an insulating layer 25 can be obtained by adjusting and controlling the thickness of the film before bonding by the intermediate bonding layer 23, that is, before sintering the adsorption electrode 24 and the insulating layer 25. The inventors of the present application have found a relationship between the film thickness before joining and the film thickness after joining, and have reached the invention of the present application.

FIG. 4 shows the membrane before joining. The second substrate 822 forms the support plate 22 shown in FIGS. 1 to 3. A conductive film 824 and an insulating film 825 are arranged on the upper surface 822a of the second substrate 822. In the conductive film 824 and the insulating film 825, the outer surface 824c of the conductive film 824 and the inner side surface 825d of the insulating film 825 are arranged apart from each other.

The conductive film 824 becomes the adsorption electrode 24 shown in FIGS. 1 to 3 by sintering. The average thickness Ct of the conductive film 824 is 40 μm or more and 150 μm or less. The average thickness Ct is, for example, the average value of the thickness in a predetermined range. The conductive film 824 is a film whose main constituent material is a mixture of _{Al 2} O _{3 and a carbide or a refractory metal.} For example, the conductive film 824 contains alumina powder, a resin component, and screen oil. The solid content ratio Cv of the conductive film 824 is 25 vol% or more and 45 vol% or less. The solids ratio (vol%) is the volume fraction, which is the ratio of the volume of solid components in the mixture to the total volume of all components before mixing.

The insulating film 825 becomes the insulating layer 25 shown in FIGS. 1 to 3 by sintering. The average thickness It of the insulating film 825 is 40 μm or more and 150 μm or less. The average thickness It is, for example, the average value of the differences in a predetermined range. The insulating film 825 is a film whose main constituent material _{is Al 2} O _3. The insulating film 825 contains alumina powder, a resin component, and screen oil. The solid content ratio Iv of the insulating film 825 is 15 vol% or more and 35 vol% or less.

The ratio of the insulating film 825 to the conductive film 824 {= (It × Iv ÷ 100) ÷ (Ct × Cv ÷ 100)} and the average thickness Ct, It are
0.6 ≤ (It x Iv ÷ 100) ÷ (Ct x Cv ÷ 100) ≤ 0.9
It> Ct
Meet. As described above, the conductive film 824 is _{formed of a conductive paste containing Al 2} O ₃ powder, AlTiC powder, and screen oil. The insulating film 825 is _{formed of an insulating paste containing Al 2} O ₃ powder, screen oil, and a resin component. That is, the conductive paste and the insulating paste are formed by weighing and kneading so as to satisfy the solid content ratio Iv of the insulating film 825 and the solid content ratio Cv of the conductive film 824. The adsorption electrode 24 and the insulating layer 25 obtained by firing the conductive film 824 and the insulating film 825 have a difference ΔT between their thicknesses T24 and T25 within a desired range (± 5 μm or less).

As described above, the electrostatic chuck 20 is a substrate in which an adsorption electrode 24 containing an AlTiC material is arranged between a mounting plate 21 made of a sapphire substrate and a support plate 22 made of alumina ceramics. That is, the electrostatic chuck 20 of the present embodiment does not use a bonding agent such as an adhesive.

As shown in FIG. 1, the electrostatic chuck 20 is bonded to the upper surface 40a of the support base 40 via a bonding agent 30. As the adhesive 30, for example, an adhesive of a heat-resistant adhesive resin such as a polyimide resin, a silicon resin, or an epoxy resin, a brazing material, or the like can be used.

The support base 40 has a flow path 41 inside. The flow path 41 is a flow path through which the refrigerant flows, and the refrigerant is supplied to the flow path 41 from the supply source 60. As the refrigerant, a gas such as helium (He) or nitrogen (N2), water, a dedicated organic solvent or the like can be used. As a result, the electrostatic chuck device 10 cools the work substrate W adsorbed on the electrostatic chuck 20.

The support base 40 has a take-out electrode 42. The take-out electrode 42 is connected to the feeding electrode 26 of the electrostatic chuck 20. The take-out electrode 42 is connected to the power supply 70. The power supply 70 supplies the voltage required for sucking the work substrate W to the suction electrode 24 via the take-out electrode 42 and the feeding electrode 26.

The electrostatic chuck device 10 shown in FIG. 1 has a focus ring 50. The focus ring 50 is arranged in the edge region of the electrostatic chuck 20. The focus ring 50 has a ring shape and is arranged along the peripheral edge of the electrostatic chuck 20. The upper surface of the focus ring 50 has a step so that the outer portion 51 is higher than the inner portion 52. The inner portion 52 of the upper surface of the focus ring 50 is positioned at the same height as the upper surface of the electrostatic chuck 20. The inner portion 52 of the upper surface of the focus ring 50 supports the edge region of the work substrate W located on the outer side of the electrostatic chuck 20. The outer portion 51 of the upper surface of the focus ring 50 is positioned so as to surround the edge region of the work substrate W. The focus ring 50 expands the electric field forming region so that the work substrate W is located at the center of the region where the plasma is formed. As a result, plasma is uniformly formed over the entire region of the work substrate W, and each region of the work substrate W is uniformly processed.

(Manufacturing process)
Next, the manufacturing process of the electrostatic chuck 20 will be described.
For convenience of explanation, the members that will eventually become each component of the electrostatic chuck 20 may be described with a name and a reference numeral that will be the final component.

As shown in FIG. 5, the first substrate 821 made of a sapphire plate is machined into a desired shape. The desired shape is, for example, a circular plate. The thickness of the first substrate 821 is, for example, 3 mm.

As shown in FIG. 6, _{the second substrate 822 made of Al 2} O ₃ is machined into a predetermined shape. The desired shape is, for example, a circular plate having a through hole 822x. The thickness of the second substrate 822 is, for example, 3 mm.

As shown in FIG. 7, the feeding electrode 826 is formed in the through hole 822x of the second substrate 822. The feeding electrode 826 can be formed, for example, by inserting a columnar member corresponding to the through hole 822x into the through hole 822x. Further, the feeding electrode 826 can be formed by filling the through hole 822x with the conductive paste.

As shown in FIG. 8, the conductive film 824 and the insulating film 825 are arranged on the upper surface 822a of the second substrate 822. The conductive film 824 is formed by applying a conductive paste by a coating method such as a screen printing method and temporarily firing the conductive paste. The insulating film 825 can be tentatively fired by applying an insulating paste by a coating method such as a screen printing method. As a temporary firing, for example, in a predetermined reduced pressure atmosphere, the heating is performed at, for example, 100 ° C. or higher.

In the step of forming the conductive film 824 and the insulating film 825 shown in FIG. 8, the step of applying the conductive paste and the insulating paste to the upper surface 822a of the second substrate 822 and the step of drying the applied conductive paste and the insulating paste are performed. Includes a step of degreasing.

As shown in FIG. 12, the conductive paste and the insulating paste are applied to the upper surface 822a of the second substrate 822 by the screen printing method to form the conductive film 824p and the insulating film 825p. The conductive paste contains Al ₂ O ₃ powder, AlTiC powder, and screen oil. The insulating paste contains Al ₂ O ₃ powder, screen oil and resin components.

The film thickness of the conductive film 824p and the insulating film 825p formed by the conductive paste and the insulating paste in one coating treatment is, for example, 20 μm to 30 μm. Further, the film thickness of the conductive film 824p formed by one coating treatment is larger than the film thickness of the insulating film 825p. Therefore, the conductive film 824 and the insulating film 825 having a desired thickness can be obtained by repeatedly coating the conductive paste and the insulating paste by repeating the coating process and the drying / degreasing process a plurality of times. Further, since the film thickness of the conductive film 824p and the film thickness of the insulating film 825p formed by one coating treatment are different, the number of treatments for applying the conductive paste and degreasing / drying, and the coating and degreasing of the insulating paste. The number of drying treatments is different from each other.

The average thickness Ct of the conductive film 824 thus formed and the average thickness It of the insulating film 825 are measured. An example of measuring the average thickness will be described.
As shown in FIG. 13, a conductive film 824 is formed inside the circular second substrate 822, and an insulating film 825 is formed so as to surround the conductive film 824. The thickness of the conductive film 824 and the insulating film 825 is measured in a non-contact manner along the four measurement lines L0, L90, L180, and L270 shown by the alternate long and short dash line in FIG. The number of measurement lines and the position of the measurement lines can be changed arbitrarily.

As shown in FIG. 14, a non-contact measuring instrument 800 is used. The measuring instrument 800 is a sensor that uses, for example, a laser beam and measures the distance to a surface on which the laser beam is reflected. The measuring instrument 800 is moved in parallel with the upper surface 822a of the second substrate 822. Then, by the measuring instrument 800, the distance from the measuring instrument 800 to the upper surface 824a of the conductive film 824, the distance from the measuring instrument 800 to the upper surface 822a of the second substrate 822, and the distance from the measuring instrument 800 to the upper surface 825a of the insulating film 825. Measure the distances of each. The difference between the distance from the measuring instrument 800 to the upper surface 824a of the conductive film 824 and the distance from the measuring instrument 800 to the upper surface 822a of the second substrate 822 is defined as the thickness of the conductive film 824. This thickness is measured a plurality of times along the measurement line L0 (, L90, L180, L270) shown in FIG. 13, and the plurality of measurement results are averaged to obtain an average thickness Ct. Similarly, the difference between the distance from the measuring instrument 800 to the upper surface 825a of the insulating film 825 and the distance from the measuring instrument 800 to the upper surface 822a of the second substrate 822 is defined as the thickness of the insulating film 825. This thickness is measured a plurality of times along the measurement line L0 (, L90, L180, L270) shown in FIG. 13, and the plurality of measurement results are averaged to obtain an average thickness It.

As shown in FIG. 9, the first substrate 821 is placed on the second substrate 822 on which the conductive film 824 and the insulating film 825 are arranged.
As shown in FIG. 10, an intermediate bonding layer 23 for bonding the first substrate 821 and the second substrate 822 is formed. The intermediate bonding layer 23 includes an adsorption electrode 24 and an insulating layer 25. The adsorption electrode 24 is formed by pressure sintering the conductive film 824 shown in FIG. 9 by, for example, a pressure sintering method. The insulating layer 25 is formed by pressure-sintering the insulating film 825 shown in FIG. 9 by, for example, a pressure sintering method. As the pressure sintering, hot press sintering can be used. As the firing conditions, the press pressure is, for example, 10 MPa, the firing temperature is, for example, 1500 ° C., and the firing time is, for example, 2 hours. As the pressure sintering, for example, discharge plasma (SPS) sintering, hot hydrostatic pressure (HIP) sintering, ultrahigh pressure synthetic sintering, gas pressure sintering, and the like can also be used.

Next, it is confirmed that the first substrate 821 and the second substrate 822 are not cracked. For this confirmation, for example, visual inspection and ultrasonic flaw detection evaluation can be used.
As shown in FIG. 11, the first substrate 821 and the second substrate 822 shown in FIG. 10 are processed by surface grinding and polishing to form a mounting plate 21 and a support plate 22 having a desired thickness. The desired thickness of the mounting plate 21 is, for example, 0.3 mm. The thickness of the support plate 22 is, for example, 0.3 mm. Further, the feeding electrode 826 shown in FIG. 10 is processed to form the feeding electrode 26 shown in FIG.

Through the above steps, the mounting plate 21, the support plate 22, the intermediate bonding layer 23 including the adsorption electrode 24 and the insulating layer 25, and the electrostatic chuck 20 having the feeding electrode 26 are formed.
Next, the electrostatic chuck 20 is joined to the support base 40 via the bonding agent 30 shown in FIG. As a result, the electrostatic chuck device 10 having the electrostatic chuck 20 and the support base 40 is formed.

Next, an evaluation method of the electrostatic chuck device 10 will be described.
In the electrostatic chuck device 10 configured as described above, the work substrate W is attracted and fixed to the electrostatic chuck 20. Then, the value of the current flowing through the work board W is measured. When the mounting plate 21 has cracks, the current value becomes larger than that in the case where the work substrate W is adsorbed and fixed to the mounting plate 21 having no cracks. Therefore, the presence or absence of cracks in the mounting plate 21 can be determined from the value of the current flowing through the work substrate W.

Further, the environmental temperature is changed within a predetermined range while the work substrate W is attracted to the electrostatic chuck device 10. The range of the environmental temperature is, for example, from −200 ° C. to 200 ° C. Then, by measuring the current value flowing through the work substrate W, it is possible to confirm the change in the resistance value of the mounting plate 21 made of the sapphire substrate. Further, by measuring the change in the surface potential of the work substrate W, for example, the rise, the change in the resistance values of the feeding electrode 26 and the suction electrode 24 can be confirmed.

[Action]
The electrostatic chuck 20 is arranged and placed between the mounting plate 21 on which the work substrate W is mounted, the support plate 22 that supports the mounting plate 21, and the mounting plate 21 and the support plate 22. An intermediate joining layer 23 for joining the plate 21 and the support plate 22 is provided. The intermediate bonding layer 23 is located in the internal region of the mounting plate 21, and includes a suction electrode 24 for generating an electrostatic force that sucks the work substrate W, and an insulating layer 25 arranged so as to surround the suction electrode 24. Has. The intermediate bonding layer 23 is obtained by bonding the mounting plate 21 and the support plate 22 by sintering, and the adsorption electrode 24 is a conductive film arranged on the upper surface 822a of the second substrate 822 which is the support plate 22. The insulating layer 25 is formed by sintering 824, and the insulating layer 25 is formed by sintering the insulating film 825 arranged on the upper surface 822a of the second substrate 822 which is the support plate 22. The conductive film 824 and the insulating film 825 have an average thickness (μm) of the conductive film 824 of Ct, a solid content ratio (vol%) of the conductive film 824 of Cv, and an average thickness of the insulating film 825 (μm) of It. When the solid content ratio (vol%) of the film 825 is Iv, the average thickness It, Ct and the solid content ratio Iv, Cv are
0.6 ≤ (It x Iv ÷ 100) ÷ (Ct x Cv ÷ 100) ≤ 0.9
It> Ct
It satisfies.

In the electrostatic chuck 20 configured in this way, the difference ΔT between the thickness T24 of the adsorption electrode 24 and the thickness T25 of the insulating layer 25 formed by sintering is small, and the mounting plate 21 and the support plate 22 in joining are Since there is little distortion, it is possible to suppress the occurrence of cracks in the mounting plate 21 and the support plate 22.

The thickness of the conductive film 824 and the insulating film 825 is 50 μm or more and 150 μm or less, and the thickness of the adsorption electrode 24 and the insulating layer 25 is 10 μm or more and 50 μm or less. The difference ΔT between the thickness T24 of the adsorption electrode 24 and the thickness T25 of the insulating layer 25 is ± 5 μm or less. In this way, since the thicknesses T24 and T25 of the adsorption electrode 24 and the insulating layer 25 constituting the intermediate bonding layer 23 that joins the mounting plate 21 and the support plate 22 can be controlled, the capacitance with little individual difference can be controlled. Chuck 20 is obtained.

[Example]
Next, an example and a comparative example of the electrostatic chuck will be described.
In Examples 1 and 2 and Comparative Examples 1 and 2 shown below, the solid content ratio Cv of the conductive film 824 is 38.4 vol%, and the solid content ratio Iv is 20.1 vol%.

(Example 1)
A c-plane sapphire substrate was used for the first substrate 821 shown in FIGS. 5, 9, and 10.
In the measurement lines L0, L90, L180, and L270 shown in FIG. 13, the average thickness Ct (μm) of the conductive film 824 is 41.7, 55.9, 40.0, 50.8, and the average thickness of the insulating film 825. It (μm) was 67.4, 90.6, 68.2, 80.1. The ratio of the conductive film 824 to the insulating film 825 on the measurement lines L0, L90, L180, and L270 {= (It × Iv ÷ 100) ÷ (Ct × Cv ÷ 100)} is 0.85, 0.85. It was 0.89 and 0.82.

(Example 2)
An a-side sapphire substrate was used for the first substrate 821 shown in FIGS. 5, 9, and 10.
In the measurement lines L0, L90, L180, and L270 shown in FIG. 13, the average thickness Ct (μm) of the conductive film 824 is 45.2, 75.3, 50.1, 66.0, and the average thickness of the insulating film 825. It (μm) was 57.1,104.1,70.0,104.0. The ratio of the conductive film 824 to the insulating film 825 on the measurement lines L0, L90, L180, and L270 {= (It × Iv ÷ 100) ÷ (Ct × Cv ÷ 100)} is 0.66, 0.72. It was 0.73 and 0.82.

(Comparative Example 1)
A c-plane sapphire substrate was used for the first substrate 821 shown in FIGS. 5, 9, and 10.
In the measurement lines L0, L90, L180, and L270 shown in FIG. 13, the average thickness Ct (μm) of the conductive film 824 is 68.5, 63.0, 84.0, 74.9, and the average thickness of the insulating film 825. It (μm) was 55.0, 49.6, 83.9, 81.5. The ratio of the conductive film 824 to the insulating film 825 on the measurement lines L0, L90, L180, and L270 {= (It × Iv ÷ 100) ÷ (Ct × Cv ÷ 100)} is 0.42, 0.41, It was 0.52, 0.57.

(Comparative Example 2)
An a-side sapphire substrate was used for the first substrate 821 shown in FIGS. 5, 9, and 10.
In the measurement lines L0, L90, L180, and L270 shown in FIG. 13, the average thickness Ct (μm) of the conductive film 824 is 79.0, 45.1, 70.8, 39.2, and the average thickness of the insulating film 825. It (μm) was 53.6, 38.0, 55.5, 38.6. The ratio of the conductive film 824 to the insulating film 825 on the measurement lines L0, L90, L180, and L270 {= (It × Iv ÷ 100) ÷ (Ct × Cv ÷ 100)} is 0.42, 0.58, It was 0.50 and 0.51.

(result)
In Comparative Examples 1 and 2, cracks were confirmed in the first substrate 821. On the other hand, in Examples 1 and 2, no crack was confirmed in the first substrate 821.

FIG. 16 shows an electrostatic chuck device 100 of a comparative example. For convenience of explanation, with respect to the constituent members of the electrostatic chuck device 100 of this comparative example, the same constituent members as those of the electrostatic chuck device 100 of the present embodiment described above are designated by the same reference numerals.

In the electrostatic chuck 110 of the electrostatic chuck device 100 of the comparative example shown in FIG. 16, the mounting plate 21 is bonded to the support plate 22 via the bonding agent 111. Since the mounting plate 21 is thin (for example, 0.3 mm), the bonding agent 111 for joining the mounting plate 21 to the support plate 22 is a processing device including the electrostatic chuck device 100, for example, a plasma processing device. It is strongly influenced by the plasma generated in. As a result, the bonding agent 111 is corroded, and dust generation and electric discharge are likely to occur.

The electrostatic chuck device 10 of the present embodiment shown in FIG. 1 has an electrostatic chuck 20 that attracts and fixes the work substrate W, and a support base 40 that has a flow path through which a refrigerant that cools the electrostatic chuck 20 flows. The electrostatic chuck 20 is arranged between the mounting plate 21 on which the work substrate W is mounted, the support plate 22 that supports the mounting plate 21, and the mounting plate 21 and the support plate 22, and is arranged between the mounting plate 21 and the support plate 22. It is provided with an adsorption electrode 24 for generating an electrostatic force for adsorbing W. The mounting plate 21 is a sapphire substrate, and the support plate 22 is an alumina ceramic. The adsorption electrode 24 has a resistance change rate of 20% or less in the range of −200 ° C. or higher and 400 ° C. or lower.

The mounting plate 21 and the support plate 22 are integrally joined via the suction electrode 24 and the insulating layer 25. That is, in the electrostatic chuck device 10 of the present embodiment, since no bonding agent is used for the electrostatic chuck 20, the generation of dust and electric discharge is suppressed. In the electrostatic chuck device 10 of the present embodiment, the bonding agent 30 is used for joining the electrostatic chuck 20 and the support base 40. However, since the bonding agent 30 is separated from the upper surface of the electrostatic chuck 20, that is, the mounting plate 21, it is not easily affected by plasma, and dust is unlikely to be generated.

[effect]
As described above, according to the present embodiment, the following effects are obtained.
(1) The electrostatic chuck 20 is arranged between the mounting plate 21 on which the work substrate W is mounted, the support plate 22 that supports the mounting plate 21, and the mounting plate 21 and the support plate 22. , An intermediate joining layer 23 for joining the mounting plate 21 and the support plate 22 is provided. The intermediate bonding layer 23 is located in the internal region of the mounting plate 21, and includes a suction electrode 24 for generating an electrostatic force that sucks the work substrate W, and an insulating layer 25 arranged so as to surround the suction electrode 24. Has. The intermediate bonding layer 23 is obtained by bonding the mounting plate 21 and the support plate 22 by sintering, and the adsorption electrode 24 is a conductive film arranged on the upper surface 822a of the second substrate 822 which is the support plate 22. The insulating layer 25 is formed by sintering 824, and the insulating layer 25 is formed by sintering the insulating film 825 arranged on the upper surface 822a of the second substrate 822 which is the support plate 22. The conductive film 824 and the insulating film 825 have an average thickness (μm) of the conductive film 824 of Ct, a solid content ratio (vol%) of the conductive film 824 of Cv, and an average thickness of the insulating film 825 (μm) of It. When the solid content ratio (vol%) of the film 825 is Iv, the average thickness It, Ct and the solid content ratio Iv, Cv are
0.6 ≤ (It x Iv ÷ 100) ÷ (Ct x Cv ÷ 100) ≤ 0.9
It> Ct
It satisfies.

In the electrostatic chuck 20 configured in this way, the difference ΔT between the thickness T24 of the adsorption electrode 24 and the thickness T25 of the insulating layer 25 formed by sintering is small, and the mounting plate 21 and the support plate 22 in joining are Since there is little distortion, it is possible to suppress the occurrence of cracks in the mounting plate 21 and the support plate 22.

(2) The thickness of the conductive film 824 and the insulating film 825 is 50 μm or more and 150 μm or less, and the thickness of the adsorption electrode 24 and the insulating layer 25 is 10 μm or more and 50 μm or less. The difference ΔT between the thickness T24 of the adsorption electrode 24 and the thickness T25 of the insulating layer 25 is ± 5 μm or less. In this way, since the thicknesses T24 and T25 of the adsorption electrode 24 and the insulating layer 25 constituting the intermediate bonding layer 23 that joins the mounting plate 21 and the support plate 22 can be controlled, the capacitance with little individual difference can be controlled. Chuck 20 is obtained.

<Change example>
In addition, each of the above-mentioned embodiments may be carried out in the following embodiments.
-For the above embodiment, the electrostatic chuck 20 may be directly bonded to the support base 40.

FIG. 15 shows a modified example of the electrostatic chuck device 10a. The electrostatic chuck device 10a has a support base 40 and an electrostatic chuck 20. The electrostatic chuck 20 is directly bonded to the upper surface 40a of the support base 40 without using the bonding agent 30 of the above embodiment. As a method of directly joining the electrostatic chuck 20 and the support base 40, room temperature joining can be used.

-For the above form, the conductive paste may contain other conductive materials such as _{titanium oxide (TiO 2).}
-For the above embodiment, a heater may be embedded in the electrostatic chuck 20. The heater may be embedded in the support base 40.

-In the above embodiment, the semiconductor wafer is used as the work substrate W, but it may be used as another work substrate, for example, a substrate used for a liquid crystal display element or the like.
-The above description is merely an exemplary explanation of the technical idea of the present invention, and a person skilled in the art can make various modifications and modifications within a range that does not deviate from the essence of the present invention. Therefore, the disclosed embodiments are not for limiting the technical idea of the present invention, but merely for explaining, and such an embodiment does not limit the scope of the technical idea of the present invention. The scope of protection of the present invention must be construed according to the scope of claims, and all technical ideas within the equivalent scope are included in the scope of rights of the present invention.

10, 10a ... Electrostatic chuck device 20 ... Electrostatic chuck 21 ... Mounting plate 21a ... Top surface 22 ... Support plate 22x ... Through hole 23 ... Intermediate bonding layer 24 ... Adsorption electrode 24c ... Outer surface 25 ... Insulation layer 25d ... Inner surface 26 ... Feeding electrode 30 ... Bonding agent 40 ... Support 40a ... Top surface 41 ... Flow path 42 ... Extraction electrode 50 ... Focus ring 51 ... Outer part 52 ... Inner part 60 ... Supply source 70 ... Power supply 100 ... Electrostatic chuck device 110 ... Electrostatic chuck 111 ... Bonding agent 800 ... Measuring instrument 821 ... First substrate 822 ... Second substrate 822a ... Top surface 822x ... Through hole 824 ... Conductive film 824a ... Top surface 824p ... Conductive film 825 ... Insulating film 825a ... Top surface 825p ... Insulation film 826 ... Feed electrode ΔT ... Difference Ct, It ... Average thickness Cv, Iv ... Solid content ratio L0, L90, L180, L270 ... Measurement line T24, T25 ... Thickness W ... Work substrate

Claims (8)

An electrostatic chuck that fixes the work board by electrostatic force.
A mounting plate on which the work board is mounted and
A support plate that supports the above-mentioned mounting plate and
An intermediate bonding layer, which is arranged between the above-mentioned mounting plate and the support plate and joins the above-mentioned mounting plate and the support plate,
With
The intermediate bonding layer is located in the inner region of the above-mentioned mounting plate, and has an adsorption electrode for generating an electrostatic force for adsorbing the work substrate to the above-mentioned mounting plate and insulation arranged so as to surround the adsorption electrode. With layers,
The intermediate bonding layer is obtained by bonding the above-mentioned mounting plate and the support plate by sintering, and the adsorption electrode is formed by sintering a conductive film arranged on the upper surface of the support plate. The insulating layer is formed by sintering an insulating film arranged on the upper surface of the support plate.
The average thickness (μm) of the conductive film is Ct, the solid content ratio (vol%) of the conductive film is Cv, the average thickness (μm) of the insulating film is It, and the solid content ratio (vol%) of the insulating film. ) Is Iv, the average thickness It, Ct and the solid content ratio Iv, Cv are
0.6 ≤ (It x Iv ÷ 100) ÷ (Ct x Cv ÷ 100) ≤ 0.9
It> Ct
Satisfy, electrostatic chuck. The thickness of the conductive film and the insulating film is 50 μm or more and 150 μm or less.
The thickness of the adsorption electrode and the insulating layer is 10 μm or more and 50 μm or less.
The difference between the thickness of the adsorption electrode and the thickness of the insulating layer is ± 5 μm or less.
The electrostatic chuck according to claim 1. The solid content ratio of the insulating film is 15 vol% or more and 35 vol% or less in terms of volume fraction.
The solid content ratio of the conductive film is 25 vol% or more and 45 vol% or less in terms of volume fraction.
The electrostatic chuck according to claim 1 or 2. The insulating film is made of a material containing _{Al 2} O _{3 as a main component.}
The conductive film is _{composed of a material containing a mixture of Al 2} O ₃ and a carbide or a refractory metal as a main component.
The electrostatic chuck according to any one of claims 1 to 3. The mounting plate is a polycrystalline _Al 2 _O 3, AlN, and any one of the constituent material of the single crystal _Al 2 _{O 3,}
The support plate is a polycrystalline _Al 2 _O 3, AlN, and any one of the constituent material of the single crystal _Al 2 _{O 3,}
The electrostatic chuck according to any one of claims 1 to 4. The electrostatic chuck according to any one of claims 1 to 5.
A support base that has a flow path through which the refrigerant flows and cools the electrostatic chuck, and
A bonding agent that joins the electrostatic chuck to the support base,
Electrostatic chuck device with. The electrostatic chuck according to any one of claims 1 to 5.
A support base that has a flow path through which the refrigerant flows and cools the electrostatic chuck, and
With
The electrostatic chuck is directly joined to the support.
Electrostatic chuck device. It is a manufacturing method of an electrostatic chuck that fixes a work substrate by electrostatic force.
The electrostatic chuck has a mounting plate on which the work substrate is mounted and a support plate for supporting the mounting plate described above.
A step of arranging the conductive paste and the insulating paste on the upper surface of the second substrate to be the support plate to form the conductive film and the insulating film.
A first substrate to be the above-mentioned mounting plate is placed on the conductive film and the insulating film, and pressure sintering is performed to bond the first substrate and the second substrate to each other, and the conductive film is formed. And the step of forming an adsorption electrode with the insulating film and forming an insulating layer with the insulating film.
Have,
The average thickness (μm) of the conductive film is Ct, the solid content ratio (vol%) of the conductive film is Cv, the average thickness (μm) of the insulating film is It, and the solid content ratio (vol%) of the insulating film. ) Is Iv, the average thickness It, Ct and the solid content ratio Iv, Cv are
0.6 ≤ (It x Iv ÷ 100) ÷ (Ct x Cv ÷ 100) ≤ 0.9
It> Ct
A method of manufacturing an electrostatic chuck that meets the requirements.

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