JP7208801B2 - holding device - Google Patents

Description

The technology disclosed in this specification relates to a holding device that holds an object.

2. Description of the Related Art A heating device (also called a “susceptor”) is known that holds an object (eg, a semiconductor wafer) and heats it to a predetermined temperature (eg, about 400 to 800° C.). A heating apparatus is used as part of a semiconductor manufacturing apparatus such as, for example, a film forming apparatus (CVD film forming apparatus, sputtering film forming apparatus, etc.) or an etching apparatus (plasma etching apparatus, etc.).

In general, a heating device includes a ceramic member having a surface (hereinafter referred to as "holding surface") substantially orthogonal to a predetermined direction and a surface opposite to the holding surface (hereinafter referred to as "back surface"). . A heater electrode composed of a heating resistor such as tungsten (W) or molybdenum (Mo) is disposed inside the ceramic member. The heater electrode is electrically connected to a conductive connecting member (also called an "electrode pad") at least partially exposed on the back surface of the ceramic member. A metal power supply member is joined to the connection member by a joint portion formed of an inactive brazing material. When a voltage is applied to the heater electrode via the power supply member and the connection member, the heater electrode generates heat to heat the object held on the holding surface of the ceramic member (see Patent Document 1, for example).

JP 2016-11254 A

In the conventional heating device, it is caused by at least one of insufficient bonding strength between the connecting member (electrode pad) and the joint (inactive brazing material) and insufficient bonding strength between the connecting member and the ceramic member. As a result, problems such as peeling of the entire connecting member, poor conduction between the connecting member and the power supply member, and disconnection (falling off) of the power supply member may occur.

In addition, such a problem is not limited to the heating device, but includes a ceramic member, an internal electrode arranged inside the ceramic member, a conductive connection member electrically connected to the internal electrode, and a metal power supply. This is a common problem in general holding devices that hold an object on the surface of a ceramic member, which includes a member and a joining portion formed of an inactive brazing material and joining a connecting member and a power supply member.

This specification discloses a technology capable of solving the above-described problems.

The technology disclosed in this specification can be implemented, for example, in the following forms.

(1) The holding device disclosed in this specification includes a ceramic member having a first surface substantially orthogonal to a first direction and a second surface opposite to the first surface; an internal electrode disposed inside the ceramic member; and a conductive connecting member electrically connected to the internal electrode, the connecting member being formed to contain a metal material and a ceramic material, and an outer peripheral portion being the ceramic. A connecting member disposed inside the member and having an inner portion other than the outer peripheral portion exposed to the second surface of the ceramic member, a metal power supply member, and an inert brazing material. A holding device for holding an object on the first surface of the ceramic member, the holding device comprising: a joint portion formed to join the inner portion of the connection member and the power supply member; , the content ratio of the metal material in the first portion including the third surface on the side facing the joint portion is adjacent to the first portion in the first direction and the A second portion having the same thickness as the first portion and including a fourth surface opposite to the third surface has a higher content of the metallic material. In this holding device, the second portion of the connecting member, which includes the fourth surface opposite to the third surface facing the joint portion, has a relatively low metal content (i.e., ceramics). material content is relatively high). Therefore, the second portion of the connecting member on the fourth surface side can be firmly bonded to the ceramic material forming the ceramic member, and the entire connecting member can be prevented from peeling off. In addition, in the present holding device, the first portion of the connection member including the third surface facing the joint has a relatively high metal material content (that is, a relatively high ceramic material content). low). Therefore, the first portion of the connecting member on the side of the third surface and the joint portion formed of the non-active brazing filler metal can be firmly joined, and the connecting member caused by peeling at the joint portion position can be firmly joined. It is possible to suppress the occurrence of poor conduction with the power supply member and detachment (falling) of the power supply member. As described above, according to the present holding device, while suppressing the occurrence of detachment of the entire connecting member, the occurrence of defective conduction between the connecting member and the power supply member and detachment (falling) of the power supply member is suppressed. can do.

(2) In the above holding device, the content of the metal material in the second portion may be 25 vol % or more and less than 70 vol %. According to this holding device, since the content of the metal material in the second portion of the connection member is not excessively high (less than 70 vol %), the second portion on the fourth surface side of the connection member is made of ceramics. It can be more strongly bonded to the ceramic material that constitutes the member, and can effectively suppress the occurrence of peeling of the entire connecting member. Further, according to this holding device, since the content of the metal material in the second portion of the connection member is not excessively low (25 vol % or more), the first portion and the second portion of the connection member It is possible to avoid an excessively large difference in the content ratio of the metal material between them, and it is possible to suppress the occurrence of peeling inside the connection member due to the difference in the content ratio of the metal material.

(3) In the holding device described above, the content of the metal material in the first portion may be 70 vol % or more. According to this holding device, it is possible to prevent the first portion including the third surface of the connecting member from being firmly joined to the ceramic material forming the ceramic member. The second part of the connection member and the ceramic material forming the ceramic member are separated from each other when exposed to a high temperature, so that the stress can be relieved and the occurrence of cracks in the connection member can be suppressed. can be done.

Note that the technology disclosed in this specification can be implemented in various forms, for example, in the form of a heating device, an electrostatic chuck, a holding device, a manufacturing method thereof, and the like. be.

1 is a perspective view schematically showing an external configuration of a heating device 100 according to this embodiment; FIG. It is an explanatory view showing roughly the XZ section composition of heating device 100 in this embodiment. FIG. 3 is an explanatory diagram showing an enlarged XZ cross-sectional configuration of a portion (X1 section in FIG. 2) of the heating device 100 in this embodiment. It is explanatory drawing which expands and shows a XZ cross-sectional structure of a part (part corresponded to the X1 part of FIG. 2) of the heating apparatus of a comparative example. FIG. 5 is an explanatory diagram showing performance evaluation results;

A. Embodiment:
A-1. Configuration of heating device 100:
FIG. 1 is a perspective view schematically showing the external configuration of a heating device 100 according to the present embodiment, and FIG. 2 is an explanatory view schematically showing the XZ cross-sectional configuration of the heating device 100 according to the present embodiment. Also, FIG. 3 is an explanatory view showing an enlarged XZ cross-sectional configuration of a part (X1 part in FIG. 2) of the heating device 100 in this embodiment. Each figure shows mutually orthogonal XYZ axes for specifying directions. In this specification, for the sake of convenience, the positive direction of the Z-axis is referred to as the upward direction, and the negative direction of the Z-axis is referred to as the downward direction. may Also, in this specification, the direction perpendicular to the Z-axis direction is referred to as the planar direction.

The heating device 100 is a device that holds an object (eg, a semiconductor wafer W) and heats it to a predetermined processing temperature (eg, about 400 to 800° C.), and is also called a susceptor. The heating apparatus 100 is used as part of a semiconductor manufacturing apparatus such as, for example, a film forming apparatus (CVD film forming apparatus, sputtering film forming apparatus, etc.) or an etching apparatus (plasma etching apparatus, etc.).

As shown in FIGS. 1 and 2, the heating device 100 includes a holder 10 and a columnar support 20. As shown in FIG.

(Configuration of holder 10)
The holding body 10 is a substantially disc-shaped member having a holding surface S1 and a back surface S2 that are substantially orthogonal to a predetermined direction (the Z-axis direction in this embodiment). The holder 10 is made of ceramics containing aluminum nitride (AlN) or alumina (Al ₂ O ₃ ) as a main component, for example. In addition, the main component here means the component with the highest content ratio (weight ratio). The diameter of the holder 10 is, for example, about 100 mm or more and 500 mm or less, and the thickness (length in the vertical direction) of the holder 10 is, for example, about 3 mm or more and 20 mm or less. The holder 10 corresponds to the ceramic member in the claims, the holding surface S1 corresponds to the first surface in the claims, and the back surface S2 corresponds to the second surface in the claims. , the Z-axis direction corresponds to the first direction in the claims.

As shown in FIG. 2, a resistance heating element 50 as a heater electrode for heating the holder 10 is arranged inside the holder 10 . The resistance heating element 50 is made of a conductive material such as tungsten or molybdenum. In this embodiment, the resistance heating element 50 forms a linear pattern extending substantially concentrically when viewed in the Z-axis direction. Both ends of the linear pattern of the resistance heating element 50 are arranged near the center of the holder 10, and upper ends of via conductors 52 are connected to the respective ends. A pair of recesses 12 are formed on the rear surface S2 side of the holder 10 , and conductive power receiving electrodes (electrode pads) 60 are provided at the positions of the respective recesses 12 . A portion of the power receiving electrode 60 (an inner portion IP to be described later) is exposed on the rear surface S2 of the holder 10 . A lower end portion of the via conductor 52 is connected to the power receiving electrode 60 . As a result, the resistance heating element 50 and the power receiving electrode 60 are electrically connected through the via conductors 52 . The resistance heating element 50 corresponds to an internal electrode in the claims, and the power receiving electrode 60 corresponds to a connecting member in the claims. The configuration of the power receiving electrode 60 will be further detailed later.

(Structure of columnar support 20)
The columnar support 20 is a substantially cylindrical member extending in the predetermined direction (vertical direction). Like the holder 10, the columnar support 20 is made of ceramics containing, for example, aluminum nitride or alumina as a main component. The outer diameter of the columnar support 20 is, for example, approximately 30 mm or more and 90 mm or less, and the height (vertical length) of the columnar support 20 is, for example, approximately 100 mm or more and 300 mm or less.

The holder 10 and the columnar support 20 are arranged such that the back surface S2 of the holder 10 and the upper surface S5 of the columnar support 20 face each other in the vertical direction. The columnar support 20 is joined near the center of the rear surface S2 of the holder 10 via a joint 30 made of a known joint material.

As shown in FIG. 2, the columnar support 20 is formed with a through hole 22 that opens toward the rear surface S2 of the holder 10 . The through-hole 22 is a hole with a substantially circular cross section that extends in substantially the same direction as the vertical direction and has a substantially constant inner diameter over the extending direction. A plurality of (two in this embodiment) electrode terminals 74 are accommodated in the through hole 22 . The electrode terminal 74 is, for example, a substantially circular columnar member as viewed in the Z-axis direction, and is made of a conductive material such as nickel (Ni). The diameter of the electrode terminal 74 is, for example, about 2 mm or more and 6 mm or less.

A buffer member 72 is arranged between the upper end of each electrode terminal 74 and each power receiving electrode 60 in the Z-axis direction. The buffer member 72 is, for example, a substantially circular plate-like member when viewed in the Z-axis direction, and is made of metal such as tungsten, molybdenum, or kovar. However, since the cushioning member 72 functions to reduce the difference in thermal expansion between the electrode terminal 74 and the power receiving electrode 60 , the material for forming the cushioning member 72 is the thermal expansion coefficient of the electrode terminal 74 and the power receiving electrode 60 Preferably, a material with a coefficient of thermal expansion between that and the coefficient of thermal expansion is used. The diameter of the buffer member 72 is, for example, about 3 mm or more and 9 mm or less, and the thickness of the buffer member 72 is, for example, about 1 mm or more and 6 mm or less. The buffer member 72 corresponds to a power supply member in the claims.

The cushioning member 72 is joined (brazed) to the lower surface (exposed surface) of the inner portion IP of the power receiving electrode 60 by a pad-side joint portion 76 made of an inactive brazing material. The non-active brazing filler metal means a brazing filler metal that does not substantially chemically bond with the ceramics. ) and Ag-based (pure Ag, etc.) brazing materials. The heating device 100 is used in an atmospheric environment of about 400 to 800° C., as will be described later. If the brazing filler metal contains an easily oxidizable component such as Cu, deterioration of the brazing filler metal may occur. Therefore, it is preferable that the brazing material does not contain an easily oxidizable component such as Cu. As shown in FIG. 3 , in the present embodiment, the pad-side joint portion 76 is formed to face the back surface S2 of the holder 10 in addition to the lower surface of the inner portion IP of the power receiving electrode 60 . However, the pad-side joint portion 76 is not joined to the holder 10 because it is made of the inactive brazing material. The pad-side joint portion 76 corresponds to the joint portion in the claims.

Also, the buffer member 72 is joined to the electrode terminal 74 by a terminal-side joint portion 78 formed of brazing material. The terminal-side joint portion 78 is, for example, Ag-based brazing material.

When a voltage is applied from a power source (not shown) to the resistance heating element 50 via each electrode terminal 74 , each buffer member 72 , each power receiving electrode 60 and each via conductor 52 , the resistance heating element 50 generates heat, and the holder 10 is heated. An object (for example, a semiconductor wafer W) held on the holding surface S1 is heated to a predetermined temperature (for example, about 400 to 800.degree. C.).

A-2. Detailed configuration of power receiving electrode 60:
The configuration of the power receiving electrode 60 will be described in further detail. The power receiving electrode 60 of this embodiment is formed to contain a metal material and a ceramic material. The metal material contained in the power receiving electrode 60 is, for example, tungsten, molybdenum, or the like. The metal material included in the power receiving electrode 60 is preferably a metal material having a thermal expansion coefficient close to that of the metal material forming the buffer member 72 . Also, the ceramic material contained in the power receiving electrode 60 is, for example, aluminum nitride or alumina. It should be noted that the ceramic material contained in the power receiving electrode 60 is preferably a ceramic material having a thermal expansion coefficient close to that of the ceramic material that is the main component of the holder 10 .

Further, the power receiving electrode 60 of the present embodiment is, for example, a substantially circular plate-like member as viewed in the Z-axis direction. However, the power receiving electrode 60 has a shape in which the outer peripheral portion is bent obliquely upward over the entire circumference. That is, the power receiving electrode 60 is composed of an outer peripheral portion OP that is bent in such a manner and positioned inside the holder 10, and a substantially flat inner portion IP that is a portion other than the outer peripheral portion OP. Of the surface (lower surface) S3 on the side facing the pad-side joint portion 76 of the power receiving electrode 60, a region corresponding to the outer peripheral portion OP is covered with the ceramic material forming the holder 10, and corresponds to the inner portion IP. The region where the contact is made is exposed on the rear surface S2 of the holder 10. As shown in FIG. The diameter of the power receiving electrode 60 is, for example, about 3 mm or more and 12 mm or less, and the thickness of the power receiving electrode 60 is, for example, about 0.005 mm or more and 0.15 mm or less. Further, the maximum thickness (maximum cover thickness) t1 of the constituent material of the holder 10 covering the outer peripheral portion OP is, for example, about 0.005 mm or more and 0.1 mm or less. The lower surface S3 of the power receiving electrode 60 corresponds to the third surface in the claims, and the surface (upper surface) S4 opposite to the lower surface S3 of the power receiving electrode 60 corresponds to the fourth surface in the claims. do.

Moreover, the power receiving electrode 60 of the present embodiment is composed of two layers, a lower layer 61 including the lower surface S3 of the power receiving electrode 60 and an upper layer 62 including the upper surface S4 of the power receiving electrode 60 . The thickness of the lower layer 61 is, for example, about 0.003 mm or more and 0.07 mm or less, and the thickness of the upper layer 62 is, for example, about 0.003 mm or more and 0.007 mm or less. The lower layer 61 and the upper layer 62 contain a metal material and a ceramic material, but the content ratio (vol %) of the metal material in the lower layer 61 is higher than the content ratio of the metal material in the upper layer 62 . Since the power receiving electrode 60 of the present embodiment has such a configuration, the content of the metal material in the first portion P1 described below of the power receiving electrode 60 is higher than the content of the metal material in the second portion described below. It's becoming In addition, the high-low relationship of the content ratio of the metal material in each of the parts P1 and P2 referred to here means the high-low relationship of the content ratio of the metal material when compared in the same volume (the same area when observing the cross section). do.
- First portion P1: A portion of the power receiving electrode 60 that includes the surface facing the pad-side joint portion 76 (that is, the lower surface S3).
- Second portion P2: of the power receiving electrode 60, adjacent to the first portion P1 in the Z-axis direction, having the same thickness as the first portion P1, and an upper surface on the side opposite to the lower surface S3 The portion containing S4.

When the thickness of the lower layer 61 and the upper layer 62 of the power receiving electrode 60 are the same, the first portion P1 is made up of only the lower layer 61, and the second portion P2 is made up of only the upper layer 62. Therefore, the content ratio of the metal material in the first portion P1 is naturally higher than the content ratio of the metal material in the second portion P2. When the lower layer 61 of the power receiving electrode 60 is thicker than the upper layer 62, the first portion P1 is made up of only the lower layer 61, while the second portion P2 is made up of the lower layer 61 and the upper layer 61. In this case also, since the first portion P1 is a portion composed only of the lower layer 61 having a high content of metal material, the metal in the first portion P1 The content of the material is higher than the content of the metal material in the second portion P2. Conversely, when the thickness of the lower layer 61 of the power receiving electrode 60 is thinner than the thickness of the upper layer 62, the second portion P2 is a portion composed only of the upper layer 62, while the first portion P1 is formed from the lower layer 61 and the lower layer 61. In this case also, since the second part P2 is a part composed only of the upper layer 62 with a low metal material content, the first part P1 The content of the metal material is higher than the content of the metal material in the second portion P2.

In addition, it is preferable that the content ratio of the metal material between the first portion P1 and the second portion P2 described above be high and low over the entire surface direction of the power receiving electrode 60 .

Moreover, the content of the metal material in the second portion P2 of the power receiving electrode 60 is preferably 25 vol % or more and less than 70 vol %. Moreover, the content of the metal material in the first portion P1 of the power receiving electrode 60 is preferably 70 vol % or more.

A-3. Manufacturing method of heating device 100:
A method for manufacturing the heating device 100 of the present embodiment is, for example, as follows. First, the holder 10 and the columnar support 20 are produced.

A method for manufacturing the holder 10 is, for example, as follows. First, to a mixture of 100 parts by weight of aluminum nitride powder, 1 part by weight of yttrium oxide (Y ₂ O ₃ ) powder, 20 parts by weight of an acrylic binder, and appropriate amounts of a dispersant and a plasticizer, an organic solvent such as toluene is added. A solvent is added and mixed in a ball mill for 20 hours to prepare a green sheet slurry. This green sheet slurry is formed into a sheet by a casting apparatus and then dried to produce a plurality of green sheets.

Alternatively, a metallized paste is prepared by adding a metal powder such as tungsten or molybdenum to a mixture of aluminum nitride powder, an acrylic binder, and an organic solvent such as terpineol and kneading the mixture. By printing this metallizing paste using, for example, a screen printer, an unsintered conductor layer that will later become the resistance heating element 50, the power receiving electrode 60, and the like is formed on each specific green sheet. In addition, by printing in a state in which via holes are provided in advance in the green sheet, an unsintered conductor portion that becomes the via conductor 52 later is formed. As the metallized paste for the power receiving electrode 60, two types of metallized pastes are prepared in which the content ratio of the metal powder such as tungsten or molybdenum and the aluminum nitride powder are different from each other. On a predetermined green sheet, first, the metallized paste having a lower metal powder content ratio among the two types of metallized paste is printed, and then the printed metallized paste having a higher metal powder content ratio is printed. Print the metallized paste on the other side. When printing the metallizing paste, for example, the metallizing paste is printed so as to have a thickness of 50 μm or more at one time, and dried to volatilize the organic solvent. This process is repeated until the set thickness is obtained. After printing each metallizing paste for the power receiving electrode 60, ceramic paste (for example, a mixture of aluminum nitride, an acrylic binder, and an organic solvent such as terpineol) is printed so as to cover the entire periphery.

Next, a plurality (for example, 20) of these green sheets are thermocompressed, and the periphery is cut as necessary to produce a green sheet laminate (for example, 8 mm thick). This green sheet laminate is cut by machining to produce a disk-shaped molded body, the molded body is degreased, and the degreased body is fired to manufacture a fired body. The surface of this sintered body is polished. The holder 10 is produced by the above steps.

Also, a method for producing the columnar support 20, for example, is as follows. First, an organic solvent such as methanol is added to a mixture of 100 parts by weight of aluminum nitride powder, 1 part by weight of yttrium oxide powder, 3 parts by weight of a PVA binder, and appropriate amounts of a dispersant and a plasticizer, followed by a ball mill. Mix to obtain a slurry. This slurry is granulated with a spray dryer to produce a raw material powder. Next, the raw material powder is filled into a rubber mold in which cores corresponding to the through holes 22 are arranged, and cold isostatic pressing is performed to obtain a compact. The molded body obtained is degreased, and the degreased body is fired. Through the steps described above, the columnar support 20 is manufactured.

Next, the holder 10 and the columnar support 20 are joined together. After the back surface S2 of the holder 10 and the upper surface S5 of the columnar support 20 are subjected to lapping as necessary, at least one of the rear surface S2 of the holder 10 and the upper surface S5 of the columnar support 20 is coated with, for example, a rare earth element or an organic compound. After uniformly applying a known bonding agent made into a paste by mixing a solvent or the like, it is degreased. Next, the back surface S2 of the holder 10 and the upper surface S5 of the columnar support 20 are superimposed and hot-pressed to bond the holder 10 and the columnar support 20 together.

After the holder 10 and the columnar support 20 are joined together, each cushioning member 72 is inserted into the through hole 22, and the upper end of each cushioning member 72 is attached to the lower surface S3 of each power receiving electrode 60 by applying an inert brazing material (for example, , Ni-based, Au-based, and Ag-based brazing materials) are used for brazing (at 950 to 1150° C. for 10 to 30 minutes) to form the pad side joint portion 76 . Further, each electrode terminal 74 is inserted into the through-hole 22, and the upper end of each electrode terminal 74 is brazed to each buffer member 72 using, for example, an Ag-based brazing material, thereby forming a terminal-side joint portion 78. Form. The heating device 100 having the configuration described above is manufactured mainly by the manufacturing method described above.

A-4. Effect of the first embodiment:
As described above, the heating device 100 of the present embodiment includes the holder 10 having the holding surface S1 substantially orthogonal to the Z-axis direction and the back surface S2 opposite to the holding surface S1. This is an apparatus for holding an object such as a semiconductor wafer W on the holding surface S1 of the . The heating device 100 includes a resistance heating element 50 , a power receiving electrode 60 , a metallic buffer member 72 , and a pad-side joint portion 76 . The resistance heating element 50 is an internal electrode arranged inside the holder 10 . The power receiving electrode 60 is a conductive member electrically connected to the resistance heating element 50, and is formed so as to contain a metal material and a ceramic material. The outer peripheral portion OP of the power receiving electrode 60 is arranged inside the holder 10 , and the inner portion IP of the power receiving electrode 60 other than the outer peripheral portion OP is exposed to the back surface S<b>2 of the holder 10 . The pad-side joint portion 76 is made of an inactive brazing material, and joins the inner portion IP of the power receiving electrode 60 and the buffer member 72 . In addition, in the heating device 100 of the present embodiment, the content ratio of the metal material in the first portion P1 including the lower surface S3 of the power receiving electrode 60 on the side facing the pad-side joint portion 76 is the first in the Z-axis direction. is higher than the metal material content in a second portion P2 adjacent to the portion P1 of and having the same thickness as the first portion P1 and including a top surface S4 opposite to the bottom surface S3. Since the heating device 100 of the present embodiment has such a configuration, as will be described in detail below, the separation between the power receiving electrode 60 and the buffer member 72 is prevented while suppressing the occurrence of peeling of the entire power receiving electrode 60 . , and detachment (dropping) of the buffer member 72 can be suppressed.

FIG. 4 is an explanatory view showing an enlarged XZ cross-sectional configuration of a portion of the heating device of the comparative example (the portion corresponding to the X1 portion in FIG. 2). A power receiving electrode 60a in the comparative example shown in FIG. , and the inner portion IP is exposed to the back surface S2 of the holder 10 . However, unlike the power receiving electrode 60 of the embodiment described above, the power receiving electrode 60a in the comparative example has a single-layer structure. Therefore, in the power receiving electrode 60a in the comparative example, the Z Assuming a second portion P2 adjacent to the first portion P1 in the axial direction and having the same thickness as the first portion P1, the content of the metal material in the first portion P1 is the second It is the same as the content of the metal material in the portion P2.

Thus, in the power receiving electrode 60a in the comparative example, the metal material content is the same between the first portion P1 including the lower surface S3 and the second portion P2 including the upper surface S4. Therefore, if the content of the metal material in the power receiving electrode 60a is relatively low (that is, the content of the ceramic material is relatively high), the pad side joint portion formed by the power receiving electrode 60a and the inert brazing material 76, and delamination at the position of the pad-side joint 76 may cause poor conduction between the power receiving electrode 60a and the cushioning member 72 or detachment (falling off) of the cushioning member 72. . Conversely, if the content of the metal material in the power receiving electrode 60a is relatively high (that is, the content of the ceramic material is relatively low), the surfaces (lower surface S3 and upper surface S4) of the power receiving electrode 60a will not support the holder 10. There is a possibility that the entire power receiving electrode 60a may be peeled off because the power receiving electrode 60a is not firmly bonded to the ceramic material constituting the power receiving electrode 60a.

In contrast, in the heating device 100 of the present embodiment, the second portion P2 of the power receiving electrode 60 including the upper surface S4 of the power receiving electrode 60 has a relatively low metal material content (that is, a ceramic material content). relatively high). Therefore, the second portion P2 on the upper surface S4 side of the power receiving electrode 60 can be firmly bonded to the ceramic material forming the holder 10, and the occurrence of peeling of the entire power receiving electrode 60 can be suppressed. . In addition, in the heating device 100 of the present embodiment, the first portion P1 of the power receiving electrode 60 including the lower surface S3 of the power receiving electrode 60 has a relatively high metal material content (that is, the ceramic material content is relatively high). low). Therefore, the first portion P1 on the lower surface S3 side of the power receiving electrode 60 and the pad side joint portion 76 formed of the inactive brazing material can be firmly joined, and peeling at the position of the pad side joint portion 76 can be achieved. It is possible to suppress the occurrence of defective conduction between the power receiving electrode 60 and the cushioning member 72 and detachment (dropping) of the cushioning member 72 due to the above. As described above, according to the heating device 100 of the present embodiment, while suppressing the occurrence of detachment of the entire power receiving electrode 60, poor conduction between the power receiving electrode 60 and the buffer member 72 and detachment of the buffer member 72 ( dropout) can be suppressed.

In addition, in the heating device 100 of the present embodiment, the content of the metal material in the second portion P2 of the power receiving electrode 60 is preferably 25 vol % or more and less than 70 vol %. By adopting such a configuration, since the content of the metal material in the second portion P2 of the power receiving electrode 60 is not excessively high (less than 70 vol %), the second portion of the power receiving electrode 60 on the side of the upper surface S4 P2 can be more strongly bonded to the ceramic material forming the holder 10, and the occurrence of peeling of the entire power receiving electrode 60 can be effectively suppressed. In addition, if such a configuration is adopted, since the content of the metal material in the second portion P2 of the power receiving electrode 60 is not excessively low (25 vol % or more), the first portion P1 of the power receiving electrode 60 and the It is possible to avoid an excessively large difference in the content ratio of the metal material between the second portion P2 and occurrence of peeling inside the power receiving electrode 60 due to the difference in the content ratio of the metal material. can be suppressed.

Moreover, in the heating device 100 of the present embodiment, the content of the metal material in the first portion P1 of the power receiving electrode 60 is preferably 70 vol % or more. As described above, in the heating device 100 of the present embodiment, the content of the ceramic material in the second portion P2 including the upper surface S4 of the power receiving electrode 60 is relatively high. Therefore, it is possible to prevent the entire power receiving electrode 60 from peeling off. Here, if the first portion P1 including the lower surface S3 of the power receiving electrode 60 also has a relatively high ceramic material content, the upper surface S4 and the lower surface S3 of the power receiving electrode 60 (however, the inside of the holder 10 is Both of the arranged portion P3 (see FIG. 4)) are firmly bonded to the ceramic material constituting the holder 10, and as a result, the stress generated when the heating device 100 is exposed to thermal cycles is relieved. crack CL may occur in the power receiving electrode 60 (for example, near the boundary between the outer peripheral portion OP and the inner portion IP). If a crack CL occurs in the power receiving electrode 60, it may cause poor conduction between the power receiving electrode 60 and the buffer member 72, or may cause rapid oxidation of the power receiving electrode 60 due to the intrusion of oxygen through the crack CL. In particular, in the configuration in which the pad-side joint portion 76 is not joined to the back surface S2 of the holder 10 because the pad-side joint portion 76 is formed of an inactive brazing material as in the present embodiment, the pad-side joint Since oxygen easily penetrates through the space between the portion 76 and the back surface S2 of the holder 10, the oxygen flows to the upper surface S4 side of the power receiving electrode 60 through the crack CL, and the power receiving electrode 60 is rapidly oxidized. is likely to occur. Moreover, as shown in FIG. 4, if the crack CL further progresses into the inside of the holder 10, peeling may occur at the crack CL, and the cushioning member 72 may come off (fall off). On the other hand, if a configuration is adopted in which the content ratio of the metal material in the first portion P1 of the power receiving electrode 60 is 70 vol % or more, the first portion P1 including the lower surface S3 of the power receiving electrode 60 can support the holder 10. It is possible to suppress strong bonding with the constituent ceramic material, and as a result, when the heating device 100 is exposed to thermal cycles, the second portion P2 of the power receiving electrode 60 and the holder 10 are formed. Separation from the ceramic material can relieve the stress, and the occurrence of cracks CL in the power receiving electrode 60 can be suppressed.

A-5. Performance evaluation:
A plurality of samples of the heating device 100 having different characteristics were produced, and the performance was evaluated using the samples. FIG. 5 is an explanatory diagram showing performance evaluation results.

A-5-1. For each sample:
As shown in FIG. 5, 12 samples (samples SA1 to SA12) of the heating device 100 were used for this performance evaluation. In samples SA1 to SA8, SA11, and SA12 among the 12 samples SA, the power receiving electrode 60 is composed of two layers, a lower layer 61 and an upper layer 62, as in the above-described embodiment. In this performance evaluation, since the thicknesses of the lower layer 61 and the upper layer 62 were set to be substantially the same, the first portion P1 is a portion composed only of the lower layer 61, and the second portion P2 is composed only of the upper layer 62. It is a composed part. On the other hand, in samples SA9 and SA10, the power receiving electrode 60 has a single-layer structure. In each sample SA, the content ratio (vol%) of the metal material in each portion (the first portion P1 and the second portion P2) of the power receiving electrode 60 is different from each other.

Further, among the 12 samples SA, samples SA1 to SA11 employ a configuration in which the outer peripheral portion OP of the power receiving electrode 60 is arranged inside the holder 10 as in the above-described embodiment. , the outer peripheral portion OP of the power receiving electrode 60 is exposed from the rear surface S2 of the holder 10, similarly to the inner portion IP.

Each sample SA was produced by a method similar to the production method described in the above embodiment. In each sample SA, aluminum nitride was used as the ceramic material contained in the holder 10 and the power receiving electrode 60, tungsten was used as the metal material contained in the power receiving electrode 60, and Ni-based brazing material was used as the pad-side joint 76. , a tungsten-based alloy was used as the metal material constituting the buffer member 72 . In each sample SA, the diameter of the power receiving electrode 60 was set to about 6.5 mm, and the thickness of the power receiving electrode 60 was set to about 0.02 mm.

A-5-2. About the evaluation method:
Bonding strength evaluation was performed for each sample SA. Specifically, a predetermined two-stage tensile load (condition 1: 200 N, condition 2: 300 N) was applied to the pad-side joint 76, and if no cracks, peeling, etc., were confirmed for each stage, the test passed ( ○), and when cracks, peeling, etc. were confirmed, it was judged to be unacceptable (×).

Moreover, thermal cycle evaluation was performed for each sample SA. Specifically, when the temperature was raised and lowered between 100° C. and 600° C. repeatedly 150 times, detachment (dropping) of the buffer member 72 and poor conduction between the power receiving electrode 60 and the buffer member 72 were not confirmed. When such detachment (falling off) or conduction failure was confirmed, it was determined to be unacceptable (×).

For each sample SA, if it is determined to be unsatisfactory (x) under the condition 1 of the bonding strength evaluation (tensile load: 200 N), the overall evaluation is determined to be unsatisfactory (x), and the condition 1 of the bonding strength evaluation is passed ( ○), but if it is determined to be unsuccessful (x) in the condition 2 of the joint strength evaluation (tensile load: 300 N), the overall evaluation is judged to be good (△), and the condition 1 of the joint strength evaluation and Condition 2 were judged to be pass (〇), but if the heat cycle evaluation was judged to be unsuccessful (×), the overall evaluation was judged to be excellent (〇), and both evaluations were judged to be pass (〇). When it was determined as such, it was determined as comprehensive evaluation: very excellent (⊚).

A-5-3. About the evaluation results:
As shown in FIG. 5, the sample SA12 was judged to be unacceptable (x) under the condition 1 (tensile load: 200 N) of the joint strength evaluation, so that the overall evaluation was judged to be unsatisfactory (x). In the sample SA12, the outer peripheral portion OP of the power receiving electrode 60 is not disposed inside the holder 10 and is exposed from the back surface S2 of the holder 10, so the bondability between the power receiving electrode 60 and the holder 10 is low. , it is considered that the condition 1 of the bonding strength evaluation was rejected.

In addition, since sample SA9 was determined to be unacceptable (x) under condition 1 (tensile load: 200 N) of the joint strength evaluation, it was determined to be overall evaluation: unsatisfactory (x). In sample SA9, since the power receiving electrode 60 has a single-layer structure and the content of the metal material in the power receiving electrode 60 is relatively low at 50 vol % (that is, the content of the ceramic material is relatively high), the power receiving electrode 60 and the pad-side joint portion 76 formed of the non-active brazing filler metal, which is considered to be the reason why the condition 1 of the joint strength evaluation was rejected.

In addition, since sample SA10 was judged to be unacceptable (x) under condition 1 (tensile load: 200 N) of the joint strength evaluation, it was judged to be overall evaluation: unsatisfactory (x). In sample SA10, the power receiving electrode 60 has a single-layer structure, and the content of the metal material in the power receiving electrode 60 is relatively high at 80 vol % (that is, the content of the ceramic material is relatively low). (lower surface S3 and upper surface S4) were not firmly bonded to the ceramic material forming the holder 10, and the condition 1 of the bonding strength evaluation was rejected.

In addition, the sample SA11 was judged to be unacceptable (x) under the condition 1 (tensile load: 200 N) of the joint strength evaluation, and thus was judged to be unsatisfactory (x) in the overall evaluation. In the sample SA11, although the power receiving electrode 60 is composed of the lower layer 61 and the upper layer 62, the metal material content in the second portion P2 including the upper surface S4 of the power receiving electrode 60 is 99%. Relatively high (that is, the content of the ceramic material is relatively low), and the content of the metal material in the first portion P1 including the lower surface S3 of the power receiving electrode 60 is relatively low at 50% (that is, the content of the ceramic material is relatively low). content is relatively high). Therefore, in sample SA11, the second portion P2 including the upper surface S4 of the power receiving electrode 60 is not strongly bonded to the ceramic material forming the holder 10, and the first portion P1 including the lower surface S3 of the power receiving electrode 60 is not strongly bonded. and the pad-side joint portion 76 formed of the non-active brazing filler metal, which is considered to be the reason why the condition 1 of the joint strength evaluation was rejected.

On the other hand, samples SA1 to SA8 were judged to be acceptable (◯) in the condition 1 of the bonding strength evaluation, and thus were judged to be overall evaluation: good (Δ) or higher. In these samples SA, the content ratio of the metal material in the second portion P2 including the upper surface S4 of the power receiving electrode 60 is the same as the content ratio of the metal material in the first portion P1 including the lower surface S3 of the power receiving electrode 60. lower than the content (that is, the content of the ceramic material in the second portion P2 is higher than the content of the ceramic material in the first portion P1). In other words, the content of the metal material in the first portion P1 is higher than the content of the metal material in the second portion P2 (that is, the content of the ceramic material in the first portion P1 is higher than the content of the ceramic material in the second portion P1). lower than the content of the ceramic material in P2). As described above, in these samples SA, since the content ratio of the ceramic material in the second portion P2 on the upper surface S4 side of the power receiving electrode 60 is relatively high, the second portion P2 on the upper surface S4 side of the power receiving electrode 60 is It is considered that the ceramic material forming the holder 10 could be firmly bonded, and the occurrence of peeling of the entire power receiving electrode 60 could be suppressed. In addition, in these samples SA, since the content ratio of the metal material in the first portion P1 on the lower surface S3 side of the power receiving electrode 60 is relatively high, the first portion P1 on the lower surface S3 side of the power receiving electrode 60 is inactivated. It can be firmly joined to the pad-side joint portion 76 formed of brazing material, and it is possible to suppress the occurrence of detachment (falling) of the cushioning member 72 due to peeling at the position of the pad-side joint portion 76 . It is considered to have been made.

Of the samples SA1 to SA8 that were judged to be good (△) or higher in the overall evaluation, samples SA6 and SA8 were judged to be unsatisfactory (x) under the condition 2 (tensile load: 300 N) of the joint strength evaluation. Comprehensive evaluation: It was determined to be good (Δ). On the other hand, samples SA1 to SA5 and SA7 were judged as pass (◯) even in condition 2 of the bonding strength evaluation, and therefore were judged as excellent (◯) or higher in overall evaluation. In samples SA6 and SA8, the content ratio of the metal material in the second portion P2 of the power receiving electrode 60 is less than 25 vol% or 70 vol% or more, whereas in samples SA1 to SA5 and SA7, the second portion The content ratio of the metal material in P2 is 25 vol% or more and less than 70 vol%. That is, in samples SA1 to SA5 and SA7, since the content ratio of the metal material in the second portion P2 on the upper surface S4 side of the power receiving electrode 60 is not excessively high (less than 70 vol%), the second portion P2 of the power receiving electrode 60 portion P2 can be more strongly bonded to the ceramic material forming the holder 10, the occurrence of peeling of the entire power receiving electrode 60 can be effectively suppressed, and the upper surface of the power receiving electrode 60 can be Since the content ratio of the metal material in the second portion P2 on the S4 side is not excessively low (25 vol % or more), the second portion P2 on the upper surface S4 side of the power receiving electrode 60 and the first portion P2 on the lower surface S3 side of the power receiving electrode 60 It is possible to avoid an excessively large difference in the content ratio of the metal material between the portion P1 and suppress the occurrence of internal peeling of the power receiving electrode 60 due to the difference in the content ratio of the metal material. It is considered to have been made.

In addition, among the samples SA1 to SA5 and SA7, which were judged to be excellent (〇) or higher in the overall evaluation, sample SA7 was judged to fail (×) in the thermal cycle evaluation, so the overall evaluation was judged to be excellent (〇). was done. On the other hand, samples SA1 to SA5 were also judged to pass (◯) in the thermal cycle evaluation, and therefore were judged to be overall excellent (⊚). In sample SA7, the content of the metal material in the first portion P1 of the power receiving electrode 60 is less than 70 vol%, while in samples SA1 to SA5, the content of the metal material in the first portion P1 is 70 vol% or more. is. That is, in the samples SA1 to SA5, since the ceramic material content ratio in the first portion P1 including the lower surface S3 of the power receiving electrode 60 is relatively low, the first portion P1 including the lower surface S3 of the power receiving electrode 60 does not cover the holding body 10. As a result, when the heating device 100 is exposed to a thermal cycle, the ceramic material constituting the lower surface S3 of the power receiving electrode 60 and the holder 10 It is considered that the stress can be relieved by peeling between the power receiving electrode 60 and the generation of the crack CL in the power receiving electrode 60 can be suppressed.

From the performance evaluation results described above, the content ratio of the metal material in the first portion P1 including the lower surface S3 on the side facing the pad-side joint portion 76 of the power receiving electrode 60 is If a configuration is adopted in which the content of the metal material is higher than that in the second portion P2 which is adjacent and has the same thickness as the first portion P1 and which includes the upper surface S4 opposite to the lower surface S3. , it was confirmed that it is possible to suppress the occurrence of detachment (dropping) of the buffer member 72 while suppressing the occurrence of peeling of the entire power receiving electrode 60 .

Further, from the performance evaluation results described above, if a configuration in which the content ratio of the metal material in the second portion P2 of the power receiving electrode 60 is 25 vol% or more and less than 70 vol% is adopted, peeling of the entire power receiving electrode 60 occurs. It was confirmed that it is possible to effectively suppress the occurrence of detachment (falling off) of the cushioning member 72 while effectively suppressing the

Furthermore, from the performance evaluation results described above, if a configuration in which the metal material content in the first portion P1 of the power receiving electrode 60 is 70 vol % or more is adopted, the power receiving electrode 60 will not crack CL even when exposed to thermal cycles. It was confirmed that it is possible to suppress the occurrence of

A-6. Method for identifying the metal material content ratio of each portion of the power receiving electrode 60:
A method of specifying the content ratio of the metal material in each portion of the power receiving electrode 60 constituting the heating device 100 is as follows. That is, the target heating device 100 is cut to expose a cross section parallel to the Z-axis direction (a direction substantially perpendicular to the holding surface S1) and including the power receiving electrode 60 . After polishing the cross section, an SEM image including the entirety of the power receiving electrode 60 in the thickness direction (Z-axis direction) is acquired. In this SEM image, a metal material (metal particles) and a ceramic material (ceramic particles) are distinguished by the difference in density. Further, the boundary line between the power receiving electrode 60 and the holding body 10 is such that the power receiving electrode 60 contains a metal material and the holding body 10 does not contain a metal material. Identify by subtracting so that In each portion (the first portion P1 and the second portion P2) of the power receiving electrode 60, a plurality of straight lines perpendicular to the Z-axis direction are drawn at a pitch of 2 μm. (A) and the total length (B) of the portion overlapping the ceramic material are calculated, and the ratio of the total (A) to the sum of the total (A) and the total (B) is the content ratio of the metal material ( vol%). The average value of the content ratio of the metal material for each straight line is calculated as the final content ratio of the metal material.

B. Variant:
The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified in various forms without departing from the scope of the invention. For example, the following modifications are possible.

The configuration of the heating device 100 in the above embodiment is merely an example, and various modifications are possible. For example, in the above embodiment, the buffer member 72 is arranged between each electrode terminal 74 and each power receiving electrode 60, but the buffer member 72 is not arranged and each electrode terminal 74 and each power receiving electrode 60 are separated from each other. It may be joined by a joint formed of an active brazing material. In such a form, the electrode terminal 74 corresponds to the power supply member in the claims.

Also, the configuration of the power receiving electrode 60 in the above embodiment is merely an example, and various modifications are possible. For example, in the above-described embodiment, the power receiving electrode 60 has a shape in which the outer peripheral portion of the substantially flat member is bent obliquely upward over the entire circumference. As long as it is arranged and the inner part IP is exposed on the back surface S2 of the holder 10, other shapes may be used. In addition, in the above embodiment, the power receiving electrode 60 includes the lower layer 61 including the lower surface S3 of the power receiving electrode 60 and the upper surface S4 of the power receiving electrode 60, and has a lower metal material content (vol%) than the lower layer 61. Although it is composed of two layers, the upper layer 62 and the upper layer 62 , another layer may be interposed between the lower layer 61 and the upper layer 62 . In this case, it is preferable that the layer closer to the upper surface S4 of the power receiving electrode 60 has a lower metal material content (a higher ceramic material content).

Further, in the above-described embodiment, the configuration of the power receiving electrode 60 electrically connected to the resistance heating element 50 arranged inside the holder 10 has been described. A power receiving electrode electrically connected to may have a similar configuration.

Further, the materials forming each member in the heating device 100 of the above-described embodiment are merely examples, and each member may be formed of another material. Moreover, the manufacturing method of the heating device 100 in the above-described embodiment is merely an example, and various modifications are possible.

In addition, the present invention is not limited to the heating device 100, but includes a ceramic member, an internal electrode (a heater electrode, a chuck electrode, an RF electrode, etc.) disposed inside the ceramic member, and a conductive electrode electrically connected to the internal electrode. a metal connecting member, a metal power supply member, and a joint formed of an inert brazing material for joining the connection member and the power supply member, and holding an object on the surface of the ceramic member Applicability to devices (eg, electrostatic chucks, etc.) is similarly applicable.

10: holder 12: recess 20: columnar support 22: through hole 30: junction 50: resistance heating element 52: via conductor 60: power receiving electrode 61: lower layer 62: upper layer 72: buffer member 74: electrode terminal 76: pad Side joint portion 78: Terminal side joint portion 100: Heating device CL: Crack IP: Inner portion OP: Peripheral portion P1: First portion P2: Second portion S1: Holding surface S2: Back surface S3: Bottom surface S4: Top surface S5 : Upper surface W: Semiconductor wafer

Claims (3)

a ceramic member having a first surface substantially orthogonal to a first direction and a second surface opposite to the first surface;
an internal electrode disposed inside the ceramic member;
A conductive connection member that is electrically connected to the internal electrode, is formed to contain a metal material and a ceramic material, has an outer peripheral portion disposed inside the ceramic member, and is other than the outer peripheral portion. a connecting member having an inner portion exposed to the second surface of the ceramic member;
a metal power supply member;
a joining portion that is formed of an inactive brazing material and joins the inner portion of the connection member and the power supply member;
A holding device for holding an object on the first surface of the ceramic member,
A content ratio of the metal material in a first portion of the connection member including a third surface on a side facing the joint portion is equal to that of the first portion of the connection member in the first direction. is adjacent to and has the same thickness as the first portion and includes a fourth surface opposite the third surface, the content of the metallic material is higher than that in a second portion;
A holding device characterized by: A holding device according to claim 1, wherein
The content ratio of the metal material in the second portion is 25 vol% or more and less than 70 vol%.
A holding device characterized by: A holding device according to claim 2, wherein
The content ratio of the metal material in the first portion is 70 vol% or more,
A holding device characterized by:

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