JP2020033236A - Conjugate - Google Patents

Abstract

To suppress reduction of conjugation strength between a ceramic member and a metal member due to C contained in an outside conductor while the outside conductor is contained in C for enhancement of adhesiveness between the outside conductor and a conjugation part.SOLUTION: A conjugate includes a ceramic member, an outside conductor arranged in a surface side of the ceramic member and mainly containing a first metal component, a metal member, and a conjugation part containing a solder material and conjugating the outside conductor and the metal member. In at least one specific cross section of the conjugate, an atom number ratio of C based on the first metal component in the outside conductor is more than 0 and 0.5 or less.SELECTED DRAWING: Figure 4

Description

  The technology disclosed in this specification relates to a joined body including a ceramic member, an external conductor, a metal member, and a joined portion.

  A heating device (also referred to as a “susceptor”) that heats an object (eg, a semiconductor wafer) to a predetermined processing temperature (eg, about 400 to 650 ° C.) while holding the object (eg, a semiconductor wafer) is known. The heating device is used as a part of a semiconductor manufacturing device such as a film forming device (such as a CVD film forming device or a sputtering film forming device) or an etching device (such as a plasma etching device).

  Generally, the heating device has a holding surface and a back surface that are substantially perpendicular to a predetermined direction (hereinafter, referred to as a “first direction”), and extends in a first direction with a plate-shaped holding member formed of ceramics. And a columnar support joined to the back surface of the holder. A resistance heating element is disposed inside the holder, and a plurality of power receiving electrodes (electrode pads) electrically connected to the resistance heating element are disposed on the back side of the holder. Further, the columnar support houses electrode terminals joined to the respective power receiving electrodes. When a voltage is applied to the resistance heating element via the electrode terminal and the power receiving electrode, the resistance heating element generates heat, and an object (for example, a semiconductor wafer) held on the holding surface of the holding body is heated to, for example, 400 to 650 ° C. Heated to a degree. The power receiving electrode and the electrode terminal (metal member) of the holder are joined by a joint formed by a brazing material containing gold and nickel. 2. Description of the Related Art Conventionally, there is known a technique for improving the bonding strength between a ceramic member and an electrode terminal by setting the porosity of a bonding portion to 0.1 to 15% (see Patent Document 1).

JP 2014-91676 A

  In the prior art in which the porosity of the joint is 0.1 to 15%, the adhesion between the external conductor (power receiving electrode) and the joint is not sufficiently ensured, and as a result, the ceramic member and the metal member ( In some cases, the joint strength with the electrode terminals cannot be sufficiently improved, and there is room for improvement.

  In addition, such a problem is not limited to a heating device. For example, a ceramic device and an external conductor such as a holding device such as an electrostatic chuck and a vacuum chuck, a heating device such as a susceptor, and a semiconductor manufacturing device component such as a shower head. This is a common problem if it is a joined body including a metal member and a joint.

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

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

(1) A joined body disclosed in the present specification includes a ceramic member, an external conductor that is disposed on the surface side of the ceramic member and has a first metal component as a main component, a metal member, and a brazing material. And a bonding part for bonding the external conductor and the metal member, wherein at least one specific cross section of the bonding body has C atoms with respect to the first metal component in the external conductor. The number ratio is greater than 0 and equal to or less than 0.5. In the present joined body, the degree of penetration of the first metal component of the external conductor into the joint is higher than in the configuration in which the atomic ratio of C (carbon) to the first metal component in the external conductor is zero. Therefore, the adhesion between the external conductor and the joint is high. Further, in the present joined body, the first metal component of the external conductor is excessively moved into the joint as compared with a configuration in which the atomic ratio of C to the first metal component in the external conductor is higher than 0.5. Therefore, formation of a gap between the ceramic member and the joint due to a defect in the external conductor is suppressed. That is, according to the present joined body, while the C is included in the outer conductor to improve the adhesion between the outer conductor and the joint, the ceramic member and the metal member are caused by the C contained in the outer conductor. Can be suppressed from decreasing the bonding strength.

(2) In the joined body, the ratio of the number of C atoms to the first metal component in the external conductor may be 0.06 or more. In the present bonded body, the adhesion between the external conductor and the bonding portion can be further improved as compared with a configuration in which the atomic ratio of C to the first metal component in the external conductor is less than 0.06. .

  Note that the technology disclosed in the present specification can be realized in various forms, for example, a ceramic device such as a holding device, an electrostatic chuck, a heater device such as a CVD heater, a vacuum chuck, and a shower head. It can be realized in the form of a joined body including an external conductor, a metal member, and a joined portion, a method of manufacturing the joined body, and the like.

FIG. 1 is a perspective view schematically illustrating an external configuration of a heating device 100 according to an embodiment. It is explanatory drawing which shows the XZ sectional structure of the heating apparatus 100 in embodiment schematically. FIG. 9 is an explanatory diagram showing performance evaluation results. It is explanatory drawing which shows typically the XZ cross-sectional structure of the vicinity of the receiving electrode in each sample.

A. This embodiment:
A-1. Configuration of heating device 100:
FIG. 1 is a perspective view schematically illustrating an external configuration of a heating device 100 according to the present embodiment, and FIG. 2 is an explanatory diagram schematically illustrating an XZ cross-sectional configuration of the heating device 100 according to the present embodiment. Note that FIG. 2 shows a part of the vicinity of a power receiving electrode 54 described later in an enlarged manner. Each drawing shows XYZ axes orthogonal to each other for specifying the direction. In the present specification, for convenience, the positive direction of the Z axis is referred to as an upward direction, and the negative direction of the Z axis is referred to as a downward direction. However, the heating device 100 is actually installed in a direction different from such a direction. You may.

  The heating device 100 is a device that heats an object (for example, a semiconductor wafer W) to a predetermined processing temperature (for example, about 400 to 650 ° C.) while holding it, and is also called a susceptor. The heating device 100 is used as a part of a semiconductor manufacturing device such as a film forming device (such as a CVD film forming device or a sputtering film forming device) or an etching device (such as a plasma etching device).

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

(Holder 10)
The holding body 10 is a substantially disk-shaped member having a holding surface S1 and a back surface S2 that are substantially perpendicular to a predetermined direction (the vertical direction in the present embodiment). The holder 10 is made of, for example, a ceramic mainly containing AlN (aluminum nitride) or Al ₂ O ₃ (alumina). Here, the main component means a component having the largest content ratio (weight ratio). The diameter of the holding body 10 is, for example, about 100 mm or more and about 500 mm or less, and the thickness (length in the vertical direction) of the holding body 10 is, for example, about 3 mm or more and about 20 mm or less.

  As shown in FIG. 2, a resistance heating element 50 as a heater for heating the holding body 10 is disposed inside the holding body 10. The resistance heating element 50 is formed of, for example, a conductive material such as tungsten or molybdenum. In the present embodiment, the resistance heating element 50 has 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 the upper end of the via conductor 52 is connected to each end. A pair of recesses 12 are formed on the back surface S2 side of the holder 10, and a power receiving electrode (electrode pad) 54 is provided in each recess 12. The lower end of the via conductor 52 is connected to the power receiving electrode 54. As a result, the resistance heating element 50 and the power receiving electrode 54 are electrically connected via the via conductor 52.

(Column support 20)
The columnar support 20 is a substantially columnar member extending in the predetermined direction (vertical direction). The columnar support 20 is made of, for example, a ceramic mainly containing AlN or Al ₂ O ₃ , similarly to the holder 10. The outer diameter of the columnar support 20 is, for example, about 30 mm or more and 90 mm or less, and the height (length in the vertical direction) of the columnar support 20 is, for example, about 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 S3 of the columnar support 20 face each other in the vertical direction. The columnar support 20 is bonded to the vicinity of the center of the back surface S2 of the holder 10 via a bonding layer 30 formed of a known bonding material.

  As shown in FIG. 2, a through-hole 22 that opens to the back surface S <b> 2 of the holder 10 is formed in the columnar support 20. The through hole 22 is a hole having a substantially circular cross section that extends in substantially the same direction as the vertical direction and has a substantially constant inner diameter in the extending direction. A plurality of (two in the present embodiment) electrode terminals 70 are accommodated in the through holes 22. The upper end of each electrode terminal 70 is joined to the power receiving electrode 54 via a joint 56 containing a brazing material. Note that the joint 56 may include a substance other than the brazing material. When a voltage is applied from a power source (not shown) to the resistance heating element 50 via each electrode terminal 70, each power receiving electrode 54, and the via conductor 52, the resistance heating element 50 generates heat and is held on the holding surface S 1 of the holding body 10. The target object (for example, semiconductor wafer W) is heated to a predetermined temperature (for example, about 400 to 650 ° C.). Note that the main component of the bonding portion 56 may be the same as the first metal component that is the main component of the power receiving electrode 54 described below, but is different from the first metal component, for example, Ni-based or Au-based. It is preferably a metal (other than an active metal). The configuration of the power receiving electrode 54 will be described in detail below.

A-2. Detailed configuration of power receiving electrode 54:
The main component of the power receiving electrode 54 is a first metal component. The first metal component is, for example, tungsten or molybdenum. The power receiving electrode 54 may include another type of metal component in addition to the first metal component as a main component. For example, the power receiving electrode 54 may include tungsten and molybdenum, and may have a configuration in which one of tungsten and molybdenum is a main component. Further, the power receiving electrode 54 may include a component other than the metal component. For example, in order to reduce the difference in thermal expansion between the holder 10 and the power receiving electrode 54, the power receiving electrode 54 preferably includes the same ceramic as the main component of the holder 10.

The power receiving electrode 54 contains C (carbon) in addition to the first metal component, and satisfies at least the following first requirement.
<First requirement>
In at least one specific cross section of the heating device 100, the atomic ratio of C to the first metal component in the power receiving electrode 54 (hereinafter, referred to as “carbon ratio”) is greater than 0 and 0.5 or less.
The carbon ratio is a ratio of the number of C atoms to the number of first metal components in the first metal component and C included in a predetermined region of the power receiving electrode 54.

Further, the power receiving electrode 54 preferably further satisfies the following second requirement.
<Second requirement>
In at least one specific cross section of the heating device 100, the carbon ratio in the power receiving electrode 54 is 0.06 or more.
Note that the carbon ratio in the power receiving electrode 54 is more preferably 0.2 or less.

  The heating device 100 corresponds to a joined body in the claims, and the holding body 10 corresponds to a ceramic member in the claims. The power receiving electrode 54 corresponds to an external conductor in the claims, and the electrode terminal 70 corresponds to a metal member in the claims. Tungsten and molybdenum correspond to the first metal component in the claims.

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

The method of manufacturing the holder 10 is, for example, as follows. First, 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 an appropriate amount of a dispersant and a plasticizer is added to an organic compound such as toluene. A solvent is added and mixed with a ball mill to prepare a green sheet slurry. The green sheet slurry is formed into a sheet by a casting device and then dried to produce a plurality of green sheets.

  A metallized paste is prepared by adding a conductive powder such as tungsten or molybdenum to a mixture of an organic solvent such as aluminum nitride powder, an acrylic binder, and terpineol and kneading the mixture. By printing this metallized paste using, for example, a screen printing apparatus, a non-sintered conductor layer that will later become the resistance heating element 50, the power receiving electrode 54, or the like is formed on a specific green sheet. In addition, by printing the green sheet in a state where via holes are provided in advance, a non-sintered conductor portion which will later become the via conductor 52 is formed.

  Next, a plurality of these green sheets (for example, 20 sheets) are thermocompression-bonded, and if necessary, the outer periphery is cut to produce a green sheet laminate. The green sheet laminate is cut by machining to form a disc-shaped molded body, the molded body is degreased, and the degreased body is fired to produce a fired body. Here, at the time of degreasing the compact, in a reducing atmosphere, the lower the temperature is, the more the residual carbon in the unsintered conductor layer that will later become the power receiving electrode 54, so the compact is removed in a state where the residual carbon is large. By firing, a fired body including the power receiving electrode 54 having a high carbon ratio can be formed. That is, by adjusting the temperature at the time of degreasing in a reducing atmosphere, the carbon ratio in the power receiving electrode 54 can be adjusted. Thereafter, the surface of the fired body is polished. Through the above steps, the holder 10 is manufactured.

  The method of manufacturing the columnar support 20 is, for example, 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 an appropriate amount of a dispersant and a plasticizer. Mix to obtain a slurry. This slurry is granulated by a spray drier to prepare a raw material powder. Next, the raw material powder is filled in a rubber mold in which a core corresponding to the through hole 22 is arranged, and cold isostatic pressing is performed to obtain a molded body. The obtained molded body is degreased, and the degreased body is further fired. Through the above steps, the columnar support 20 is manufactured.

  Next, the support 10 and the columnar support 20 are joined. After performing a lapping process on the back surface S2 of the support 10 and the upper surface S3 of the columnar support 20, if necessary, at least one of the rear surface S2 of the support 10 and the upper surface S3 of the columnar support 20 is provided with a rare earth or organic material. A known bonding agent that is made into a paste by mixing a solvent or the like is uniformly applied, and then degreased. Next, the back surface S2 of the support 10 and the upper surface S3 of the columnar support 20 are overlapped with each other, and hot press firing is performed to join the support 10 and the columnar support 20 together.

  After the holding body 10 and the columnar support body 20 are joined, the respective electrode terminals 70 are inserted into the respective through holes 22, and the upper end of the respective electrode terminals 70 is inserted into the respective power receiving electrodes 54, for example, at about 950 ° C. to 1200 ° C. The joining portion 56 was formed by brazing with a foil brazing material in a vacuum. By the above manufacturing method, the heating device 100 having the above-described configuration is manufactured.

A-4. Effects of this embodiment:
As described above, in the heating device 100 of the present embodiment, the first metal component of the power receiving electrode 54 is in the bonding portion 56 as compared with the configuration in which the carbon ratio in the power receiving electrode 54 (external conductor) is 0. Since the degree of intrusion increases, the adhesion between the power receiving electrode 54 and the joint 56 increases. Further, in the present embodiment, the first metal component included in the power receiving electrode 54 is suppressed from being excessively moved into the bonding portion 56 as compared with the configuration in which the carbon ratio of the power receiving electrode 54 is higher than 0.5. In addition, formation of a gap between the holder 10 and the joint 56 due to a defect of the power receiving electrode 54 is suppressed. That is, according to the present joined body, the C is included in the power receiving electrode 54 in order to improve the adhesion between the power receiving electrode 54 and the joint portion 56, and the holder 10 and the electrode 10 are caused by the C included in the power receiving electrode 54. A decrease in the bonding strength with the terminal 70 can be suppressed.

  In the present embodiment, the carbon ratio of the power receiving electrode 54 is equal to or greater than 0.06. According to the present embodiment, the carbon ratio of the power receiving electrode 54 is smaller than that of the power receiving electrode 54 that is less than 0.06. Adhesion with the portion 56 can be further improved.

A-5. Performance evaluation:
Samples of a plurality of heating devices (heating device 100) were manufactured, and performance evaluation was performed using the manufactured samples of the plurality of heating devices. FIG. 3 is an explanatory diagram showing performance evaluation results, and FIG. 4 is an explanatory diagram schematically showing an XZ cross-sectional configuration near a power receiving electrode in each sample.

A-5-1. For each sample:
As shown in FIG. 3, the performance evaluation was performed on samples 1 to 3 of the heating device. Samples 1 to 3 are common in that the joint (brazing material) includes W (tungsten) and C (carbon) as main components (first metal components). (External conductors) have different carbon ratios. The carbon ratio can be specified by the following method. First, the concentration (tungsten concentration, carbon concentration) of each component element included in the power receiving electrode is specified for a specific cross section (for example, XZ cross section) near the power receiving electrode in each sample. The tungsten concentration is the atomic ratio of W (atm%) in the component elements included in the power receiving electrode 54, and the carbon concentration is the atomic ratio of C (atm%) in the component elements included in the power receiving electrode 54. Next, the carbon ratio can be specified by dividing the carbon concentration by the tungsten concentration. In addition, the concentration (atm%) of each component element in each sample can be specified by quantitative analysis of EPMA (Electron Probe Micro Analyzer).

  In sample 1, the carbon ratio in the power receiving electrode 54 is 0.6 or more and 1 or less. FIG. 4A shows an XZ cross-sectional configuration near the power receiving electrode in Sample 1. In the vicinity of XA in FIG. 4A, the tungsten concentration is 54.89 (atm%), and the carbon concentration is 36. 07 (atm%). In sample 2, the carbon ratio in the power receiving electrode 54 is 0.25 or more and 0.2 or less. FIG. 4B shows an XZ cross-sectional configuration near the power receiving electrode in Sample 2. In the vicinity of XB in FIG. 4B, the tungsten concentration is 72.45 (atm%), and the carbon concentration is 17.2%. 98 (atm%). In Sample 3, the carbon ratio in the power receiving electrode 54 is 0.06 or more and 0.12 or less. FIG. 4C shows an XZ cross-sectional configuration near the power receiving electrode in Sample 32. In the vicinity of XC in FIG. 4C, the tungsten concentration is 58.60 (atm%), and the carbon concentration is 16. 494 (atm%). That is, sample 1 does not satisfy the first requirement, and samples 2 and 3 both satisfy the first requirement and the second requirement.

A-5-2. About the evaluation method:
“Ni movement” in FIG. 3 means whether or not Ni, which is a material for forming the joint, has moved into the power receiving electrode. The presence or absence of Ni movement can be identified by quantitative analysis of EPMA on one cross section of the power receiving electrode. The “joining strength test” means whether or not a crack (crack) has occurred in any of the holder 10, the power receiving electrode 54, and the joint 56 when a predetermined tensile load is applied to the joint. Specifically, using a known precision universal testing machine, a tensile load is applied to the sample (heating device) in a direction to separate the holder from the electrode terminal (electrode terminal 70), and thereafter, It was visually determined whether or not cracks occurred near the joint 56 in one cross section.

A-5-3. About evaluation results:
In the sample 1, as shown in FIG. 4A, the power receiving electrode 54 contains C (carbon), so that the material for forming the power receiving electrode 54 has high wettability, and the first metal component ( Since the degree of penetration of the semiconductor wafer W) into the joint 56 is increased, the adhesion between the power receiving electrode 54 and the joint 56 is increased. However, a gap H is formed between the holder 10 and the power receiving electrode 54 due to the movement and diffusion of many first metal components (W) into the joint 56. As described above, in the sample 1, the carbon ratio of the power receiving electrode 54 is 0.06 or more, so that the first metal component of the power receiving electrode 54 excessively moves into the joint 56. As a result, a portion where the power receiving electrode 54 does not exist is generated between the holder 10 and the joint 56. It is considered that the gap H is formed between the holding body 10 and the power receiving electrode 54 because the ceramics forming the holding body 10 and the brazing material forming the bonding portion 56 have low bondability to each other. Further, as shown in FIG. 3, in Sample 1, Ni, which is the main component of the joint 56, was moved into the power receiving electrode 54. Further, in Sample 1, cracks were confirmed in the bonding strength test.

  On the other hand, in Samples 2 and 3, as shown in FIGS. 4B and 4C, since the power receiving electrode 54 contains C (carbon), the adhesion between the power receiving electrode 54 and the joint 56 is also increased. Is high. Further, in Samples 2 and 3, no gap is formed between the holder 10 and the power receiving electrode 54. Further, as shown in FIG. 3, in Samples 2 and 3, Ni, which is the main component of the joint 56, hardly moved into the power receiving electrode 54. In samples 2 and 3, cracks were not observed in the bonding strength test. From these results, as described above, when the heating device 100 satisfies the first requirement, the power receiving electrode 54 includes C in order to improve the adhesion between the power receiving electrode 54 and the bonding portion 56, and the power receiving electrode 54 includes C. It can be seen that a decrease in the bonding strength between the holder 10 and the electrode terminal 70 due to C contained in the electrode 54 can be suppressed.

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

  The configuration of the heating device 100 in the above embodiment is merely an example, and can be variously modified. For example, in the above embodiment, the outer shape of the holding body 10 and the columnar support body 20 as viewed in the Z-axis direction is substantially circular, but may be other shapes. Further, the electrode terminals accommodated in the through holes 22 formed in the columnar support body 20 are not limited to the terminals electrically connected to the resistance heating element 50, but may be, for example, a high frequency (RF) electrode for generating plasma. The terminal may be a terminal that is electrically connected or a terminal that is electrically connected to an attraction electrode for electrostatic attraction. Further, in the above-described embodiment, the power receiving electrode 54 is arranged in the concave portion 12 formed on the back surface S2 of the holding body 10, but may be arranged on the back surface S2 of the holding body 10. In short, the power receiving electrode only needs to be arranged on the second surface side of the holder. In addition, the external conductor is not limited to the power receiving electrode 54, but may be any conductor as long as it is disposed on the surface side of the ceramic member. In addition, the metal member is not limited to the electrode terminal 70, and in short, may be a metal member disposed to face the external conductor in the first direction.

  Further, the material for forming each member constituting the heating device 100 in the above embodiment is merely an example, and each member may be formed of another material. For example, in the heating device 100 in the above embodiment, the holder 10 and the columnar support 20 are made of ceramics containing aluminum nitride or alumina as a main component, but at least one of the holder 10 and the columnar support 20 is used. However, it may be made of other ceramics. The columnar support 20 may be made of a material other than ceramics (for example, a metal such as aluminum or an aluminum alloy). Similarly, the material for forming the electrode terminals 70 and the like may be another material. The power receiving electrode 54 may include a metal component other than tungsten or molybdenum as a main component. In addition, the power receiving electrode 54 may include a component other than the metal component, such as glass, in addition to the metal component. In the above-described embodiment, the power receiving electrode 54 is exemplified as the external conductor. However, the present invention is not limited to this, and the external conductor may be a conductor partially embedded in the holder 10 and exposed to the outside.

  In the above embodiment, the power receiving electrode 54 may have a configuration that does not satisfy the second requirement. Further, the carbon ratio in the power receiving electrode 54 may be higher than 0.2. The specific cross section is not limited to the XZ cross section of the heating device 100, and may be another cross section such as an XY cross section of the heating device 100.

  The present invention is not limited to a heating device, but is also applicable to a holding device such as an electrostatic chuck and a vacuum chuck, a heating device such as a susceptor, and a part for a semiconductor manufacturing device such as a shower head. In short, the present invention is applicable to a joined body including a ceramic member formed of ceramics, an external conductor, a metal member, and a joint.

  The method of manufacturing the heating device 100 in the above embodiment is merely an example, and can be variously modified. For example, the holder 10 may be formed by a press molding method.

10: Holder 12: Concave 20: Columnar support 22: Through hole 30: Bonding layer 32: Sample 50: Resistance heating element 52: Via conductor 54: Power receiving electrode 56: Joint 70: Electrode terminal 100: Heating device H: Gap S1: holding surface S2: back surface S3: top surface W: semiconductor wafer

Claims (2)

A ceramic member,
An external conductor that is disposed on the surface side of the ceramic member and has a first metal component as a main component;
Metal members,
Including a brazing material, a joining portion that joins the external conductor and the metal member,
In at least one specific cross section of the joined body, the atomic ratio of C to the first metal component in the outer conductor is greater than 0 and 0.5 or less;
A joined body characterized in that: The conjugate according to claim 1,
The ratio of the number of atoms of C to the first metal component in the external conductor is 0.06 or more.
A joined body characterized in that:

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