Ceramic base

Abstract

The invention provides a ceramic base which is not easy to cause conduction failure caused by connection failure of internal electrodes. The ceramic base includes: a ceramic base body having a first surface on which a wafer is placed and a second surface facing the first surface; an internal electrode implanted in the ceramic base body; and a terminal, one end of which is connected to the internal electrode and the other end of which reaches the second surface of the ceramic base body. The internal electrode has a horizontal portion provided parallel to the first surface, and a non-horizontal portion extending from the horizontal portion toward the first surface or the second surface. The horizontal part and the non-horizontal part are integrally formed by bending one electrode, so that a bent part forming a boundary between the horizontal part and the non-horizontal part exists.

Description

Technical Field

[0001] The invention relates to a ceramic base. Background Art

[0002] As a ceramic base for semiconductor manufacturing equipment, there is known a base in which an internal electrode having a structure in which an electrode extending in the horizontal direction and an electrode extending in the vertical direction are electrically connected is embedded.

[0003] Patent document 1 (Japanese Patent Application Publication No. 2003-163259) discloses a ceramic component having an internal electrode embedded in a ceramic body. The internal electrode is formed by connecting a first electrode sheet and a second electrode sheet separated from each other in the thickness direction of the body via a coil-shaped conductive member.

[0004] Patent Document 2 (Japanese Patent No. 6754890) discloses a wafer support table with an RF electrode and a heater electrode embedded within a disc-shaped ceramic substrate. The RF electrode consists of multiple RF segment electrodes on the same plane, with a first RF segment electrode positioned inside a predetermined circle and a second RF segment electrode positioned outside the circle. The second RF segment electrode is connected to a second RF segment electrode conductor via a jumper wire. The upper ends of internal terminals are connected at two points on the back surface of the second RF segment electrode. The jumper wire is a conductive, strip-shaped mesh sheet parallel to the wafer placement surface.

[0005] Patent Document 3 (Japanese Patent Application Laid-Open No. 2020-202372) discloses a ceramic structure including a first conductive structure and a second conductive structure electrically connected via an electrically conductive connecting member capable of compensating for shrinkage in the vertical direction of a ceramic sheet.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-163259

[0009] Patent Document 2: Japanese Patent No. 6754890

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 2020-202372 Summary of the Invention

[0011] Conventional internal electrodes embedded in a ceramic base, as disclosed in Patent Documents 1 to 3, have a structure in which horizontal electrodes arranged in the horizontal direction and vertical electrodes arranged in the vertical direction are connected together. However, since these conventional internal electrodes are constructed by joining the horizontal and vertical electrodes together, there is a problem of poor conductivity caused by connection failure.

[0012] The inventors of the present invention have recently discovered that by using an internal electrode having a horizontal portion and a non-horizontal portion integrally formed by bending a single electrode, a ceramic base can be provided that is less susceptible to conduction failure caused by connection failure of the internal electrode.

[0013] Therefore, an object of the present invention is to provide a ceramic base in which a conduction failure caused by a connection failure of an internal electrode is less likely to occur.

[0014] According to the present invention, the following solutions are provided.

[0015] [Scheme 1]

[0016] A ceramic base, comprising:

[0017] a ceramic base body having a first surface on which a wafer is placed and a second surface opposite to the first surface;

[0018] an internal electrode embedded in the ceramic base body; and

[0019] a terminal having one end connected to the internal electrode and the other end reaching the second surface of the ceramic base body,

[0020] The internal electrode includes: a horizontal portion arranged parallel to the first surface, and a non-horizontal portion extending from the horizontal portion toward the first surface or the second surface. The horizontal portion and the non-horizontal portion are formed integrally by bending a piece of electrode, so that there is a bent portion forming a boundary between the horizontal portion and the non-horizontal portion.

[0021] [Scheme 2]

[0022] The ceramic base according to claim 1, wherein:

[0023] The internal electrode is composed of a metal mesh.

[0024] [Scheme 3]

[0025] The ceramic base according to claim 1 or 2, wherein:

[0026] The angle formed by the horizontal portion and the non-horizontal portion at the bending portion is 50 to 130 degrees.

[0027] [Scheme 4]

[0028] The ceramic susceptor according to any one of claims 1 to 3, wherein

[0029] The number of the non-horizontal parts is 1 to 100.

[0030] [Scheme 5]

[0031] The ceramic susceptor according to any one of claims 1 to 4, wherein

[0032] The ceramic base body is made of aluminum nitride and / or aluminum oxide.

[0033] [Scheme 6]

[0034] The ceramic susceptor according to any one of claims 1 to 5, wherein:

[0035] The single electrode includes a disk-shaped electrode main portion and an extension portion extending from the electrode main portion. The electrode main portion constitutes the horizontal portion, and the extension portion is bent to constitute the non-horizontal portion.

[0036] [Scheme 7]

[0037] The ceramic susceptor according to any one of claims 1 to 6, wherein:

[0038] The one electrode has a disk-shaped electrode main portion and an extension portion extending from the electrode main portion.

[0039] The portion of the electrode main portion corresponding to the base of the extension portion is formed with a pair of cutouts for enabling bending at a position further inward than the outer periphery of the electrode main portion.

[0040] The electrode is bent at a position inside the electrode main part in a form including a root portion defined by the pair of cutouts, so that the extension portion and the root portion constitute the non-horizontal portion, and the remaining portion of the electrode main part except the root portion constitutes the horizontal portion.

[0041] [Scheme 8]

[0042] The ceramic susceptor according to any one of claims 1 to 7, wherein:

[0043] The non-horizontal portion of the internal electrode reaches the first surface.

[0044] [Scheme 9]

[0045] The ceramic base according to claim 8, wherein:

[0046] The internal electrode functions as a ground electrode.

[0047] [Scheme 10]

[0048] The ceramic base according to claim 9, wherein:

[0049] The ceramic susceptor is used in an ion implantation apparatus or a physical vapor deposition (PVD) apparatus.

[0050] [Scheme 11]

[0051] The ceramic susceptor according to any one of claims 1 to 7, wherein:

[0052] The ceramic base body includes: a first disk-shaped layer constituting the first surface; and a second disk-shaped layer having a larger diameter than the first layer and constituting the second surface, wherein the second layer extends along the outer circumference of the ceramic base body beyond the outer circumferential end of the first layer to form an outer peripheral step portion.

[0053] The ceramic base further includes a second internal electrode that is implanted in the outer peripheral step portion of the second layer and is connected to the internal electrode.

[0054] [Scheme 12]

[0055] The ceramic base according to claim 11, wherein

[0056] The internal electrode includes the horizontal portion implanted in the first layer and the non-horizontal portion implanted in the first layer and the second layer.

[0057] The second internal electrode is implanted in the outer peripheral portion of the second layer including the outer peripheral step portion in parallel with the horizontal portion, and is connected to the lower end of the non-horizontal portion.

[0058] [Scheme 13]

[0059] The ceramic base according to claim 11 or 12, wherein:

[0060] The internal electrode and the second internal electrode are separate electrodes.

[0061] [Scheme 14]

[0062] The ceramic base according to claim 11 or 12, wherein:

[0063] The internal electrode and the second internal electrode are integrally formed by bending a single electrode.

[0064] [Scheme 15]

[0065] The ceramic susceptor according to any one of claims 11 to 14, wherein

[0066] The ceramic susceptor is used in a film forming apparatus or an etching apparatus using plasma. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is a schematic cross-sectional view showing one embodiment of the ceramic susceptor according to the present invention.

[0068] Figure 2 Yes Figure 1 A simplified top view of the ceramic base is shown.

[0069] Figure 3 It means that one electrode is used to make Figure 1 and Figure 2 A diagram showing the steps of forming the internal electrode in the ceramic base.

[0070] Figure 4 This is a photograph showing an example of an internal electrode having a horizontal portion and a non-horizontal portion integrally formed by bending a metal mesh.

[0071] Figure 5 This figure shows an example of producing an internal electrode from a single electrode having a pair of cutouts.

[0072] Figure 6 It is a schematic cross-sectional view showing another embodiment of the ceramic susceptor according to the present invention. DETAILED DESCRIPTION

[0073] The ceramic susceptor according to the present invention is a ceramic table used to support a wafer W in semiconductor manufacturing equipment. For example, the ceramic susceptor according to the present invention can be a ceramic heater used in semiconductor film formation equipment or an electrostatic chuck used in semiconductor etching equipment. Typical examples of film formation equipment include CVD (chemical vapor deposition) equipment (e.g., thermal CVD equipment, plasma CVD equipment, optical CVD equipment, and MOCVD equipment) and PVD (physical vapor deposition) equipment.

[0074] Figure 1 and Figure 2 An example of a ceramic base is shown in FIG. Figure 1 and Figure 2The ceramic base 10 shown includes a ceramic base body 12, an internal electrode 14, and a terminal 16. The ceramic base body 12 has a first surface 12a on which a wafer W is placed, and a second surface 12b opposite the first surface 12a. The internal electrode 14 is embedded in the ceramic base body 12. One end of the terminal 16 is connected to the internal electrode 14, and the other end reaches the second surface 12b of the ceramic base body 12. The internal electrode 14 has a horizontal portion 14a parallel to the first surface 12a, and a non-horizontal portion 14b extending from the horizontal portion 14a toward the first surface 12a or the second surface 12b. The horizontal portion 14a and the non-horizontal portion 14b are integrally formed by bending a single electrode, resulting in a bent portion 14c that forms the boundary between the horizontal portion 14a and the non-horizontal portion 14b. By employing the internal electrode 14 having the horizontal portion 14 a and the non-horizontal portion 14 b integrally formed by bending a single electrode, it is possible to provide the ceramic base 10 in which conduction failure due to connection failure of the internal electrode 14 is less likely to occur.

[0075] As described above, in the conventional bases disclosed in Patent Documents 1 to 3, the internal electrodes are formed by joining horizontal electrodes and vertical electrodes, which causes the problem of poor conduction due to connection failure. According to the ceramic base 10 of the present invention, this problem is eliminated. That is, the internal electrode 14 used in the present invention is as follows. Figure 3 As shown in the example, a single electrode 13 (particularly the extension 13b) is bent and integrally formed to have a horizontal portion 14a and a non-horizontal portion 14b. Therefore, the boundary between the horizontal portion 14a and the non-horizontal portion 14b, i.e., the bent portion 14c, is not formed by joining separate electrodes but is essentially derived from the single electrode 13. Therefore, a robust structure is ensured even at the angled boundary (i.e., the bent portion 14c), which is prone to connection failures in conventional configurations, resulting in less likely connection failures.

[0076] The ceramic base body 12 is a ceramic plate that forms the matrix into which the internal electrodes 14 and terminals 16 of the ceramic base 10 are implanted. It can be constructed similarly to ceramic plates used in conventional ceramic bases. The ceramic base body 12 is preferably made of aluminum nitride and / or aluminum oxide, due to its excellent thermal conductivity, high electrical insulation, and thermal expansion characteristics similar to those of silicon.

[0077] The ceramic base body 12 preferably has a disc-like shape. However, the disc-like shape of the ceramic base body 12 does not need to be a perfect circle when viewed from above; for example, it may be an incomplete circle with a missing portion, such as an orientation flat. The dimensions of the ceramic base body 12 are not particularly limited and can be appropriately determined based on the diameter of the wafer W to be used. In the case of a circular shape, the diameter is typically 150 to 450 mm, for example, approximately 300 mm.

[0078] As described above, the internal electrode 14 has the horizontal portion 14a and the non-horizontal portion 14b. The horizontal portion 14a and the non-horizontal portion 14b are as follows. Figure 3 As shown, a single electrode 13 (particularly an extension 13b) is formed integrally by bending, resulting in a bent portion 14c that forms the boundary between the horizontal portion 14a and the non-horizontal portion 14b. Preferably, the single electrode 13 includes a disc-shaped main electrode portion 13a and an extension 13b extending from the main electrode portion 13a. The main electrode portion 13a constitutes the horizontal portion 14a, and the extension 13b is bent to constitute the non-horizontal portion 14b.

[0079] The internal electrode 14 is not particularly limited as long as it is a bendable conductive component. It is preferably made of a metal such as molybdenum or tungsten, which has a thermal expansion coefficient close to that of aluminum nitride or aluminum oxide. Figure 4 The example shown is composed of a single piece of metal mesh. The metal mesh has the advantage that when the molded body with the internal electrodes 14 embedded therein is fired to produce the ceramic base body 12, the metal mesh can be compressed and deformed to follow the shrinkage associated with firing. This can mitigate the shrinkage during firing, more effectively preventing connection failures at the bent portion 14c.

[0080] The metal mesh may have a mesh structure formed by a plurality of metal wires interlaced with each other, and is not particularly limited. The diameter (wire diameter) of the metal wires constituting the metal mesh is not particularly limited, but is preferably 0.20 to 0.50 mm, more preferably 0.25 to 0.45 mm, and even more preferably 0.30 to 0.40 mm. The mesh size (the size of the gaps between the meshes) of the metal mesh is not particularly limited, but is preferably 0.50 to 0.90 mm, more preferably 0.60 to 0.80 mm, and even more preferably 0.65 to 0.75 mm.

[0081] The horizontal portion 14a is provided parallel to the first surface 12a in the ceramic base body 12. However, the horizontal portion 14a does not need to be completely parallel to the first surface 12a, and may be provided substantially horizontally to such an extent that the function as the internal electrode 14 is not impaired.

[0082] The non-horizontal portion 14b extends from the horizontal portion 14a toward the first surface 12a or the second surface 12b. Figure 1 As shown, the non-horizontal portion 14b may extend from the horizontal portion 14a toward the first surface 12a. Alternatively, as described later Figure 6 As shown, the non-horizontal portion 14b may extend from the horizontal portion 14a toward the second surface 12b.

[0083] The angle formed between the horizontal portion 14a and the non-horizontal portion 14b at the bent portion 14c is preferably 50 to 130°, more preferably 60 to 120°, even more preferably 70 to 110°, particularly preferably 80 to 100°, and most preferably 85 to 95°, for example, 90°. In other words, the non-horizontal portion 14b is most preferably a so-called longitudinal electrode. An angle within this range reduces the risk of damage to the electrode 13 due to bending, and reduces the risk of conduction failure at the bent portion 14c.

[0084] The number of the non-horizontal portions 14 b is preferably 1 to 100, more preferably 2 to 40, further preferably 2 to 20, particularly preferably 2 to 10, and most preferably 2 to 6, for example, 4.

[0085] As described above, the electrode 13 before bending may include a disk-shaped electrode main portion 13a and an extension portion 13b extending from the electrode main portion 13a. In this case, it is preferable to Figure 5 As shown, a pair of notches 13c are formed in the portion of the electrode main portion 13a corresponding to the base of the extension portion 13b, allowing for bending inward from the outer periphery of the electrode main portion 13a. In this configuration, preferably, a single electrode 13 is bent inward from the electrode main portion 13a to include a root portion 13d defined by the pair of notches 13c. Thus, the extension portion 13b and the root portion 13d constitute the non-horizontal portion 14b, and the remainder of the electrode main portion 13a excluding the root portion 13d constitutes the horizontal portion 14a. This configuration improves the stability of the bent portion 14c compared to a case where the electrode main portion 13a or the horizontal portion 14a is bent at or outside the outer periphery.

[0086] exist Figure 1In the ceramic base 10 shown, the non-horizontal portion 14b of the internal electrode 14 reaches the first surface 12a. In this case, the end of the non-horizontal portion 14b is exposed on the first surface 12a, so that the non-horizontal portion 14b is in contact with the chip W placed on the first surface 12a. As a result, the chip W can be grounded or de-electrified by means of the internal electrode 14 and the terminal 16. In other words, the internal electrode 14 can function as a grounding electrode. Specifically, one end of the terminal 16 is connected to the internal electrode 14 (typically the horizontal portion 14a), and the other end of the terminal 16 reaches the second surface 12b of the ceramic base body 12, so that the internal electrode 14 can be grounded by means of the terminal 16. The ceramic base 10 with such a structure capable of de-electrification can be preferably used in an ion implantation device or a physical vapor growth (PVD) device. However, depending on the application, it can be as described later. Figure 6 As shown in the ceramic base 10 ′, the non-horizontal portion 14 b of the internal electrode 14 extends toward the second surface 12 b (not toward the first surface 12 a ) (does not reach the second surface 12 b but extends just before it).

[0087] The outer peripheral end portion of the ceramic base body 12 may be Figure 1 The flat shape shown, however, Figure 6 As shown, it can be stepped. Figure 6In the illustrated ceramic base 10', the ceramic base body 12' includes a disc-shaped first layer 12c forming a first surface 12a, and a disc-shaped second layer 12d having a larger diameter than the first layer 12c and forming a second surface 12b. The second layer 12d extends along the outer periphery of the ceramic base body 12' beyond the outer peripheral end of the first layer 12c, forming a peripheral step 12e. In this case, the ceramic base 10' preferably further includes a second internal electrode 15, which is embedded in the peripheral step 12e of the second layer 12d and connected to the internal electrode 14. For example, the internal electrode 14 includes a horizontal portion 14a embedded in the first layer 12c and a non-horizontal portion 14b embedded in both the first layer 12c and the second layer 12d. The second internal electrode 15 is embedded in the outer periphery of the second layer 12d, including the peripheral step 12e, parallel to the horizontal portion 14a, and is connected to the lower end of the non-horizontal portion 14b. According to this structure, in a susceptor facing a film forming apparatus or etching apparatus using plasma, a high-frequency voltage can be applied to the outer periphery of the wafer W to improve the uniformity of the plasma. In other words, the internal electrode 14 can function as an RF electrode for plasma generation. Therefore, a ceramic susceptor 10 having a second internal electrode 15 on such an outer peripheral step 12e can be preferably used in a film forming apparatus or etching apparatus using plasma. The internal electrode 14 and the second internal electrode 15 can be separate electrodes or formed integrally by bending a single electrode. In short, from the perspective of improving the uniformity of the plasma at the outer periphery of the wafer W, the second internal electrode 15 is preferably configured in a ring shape that surrounds the disc-shaped electrode main portion 13a along the outer periphery when viewed from above.

[0088] As described above, one end of terminal 16 is connected to internal electrode 14, and the other end reaches second surface 12b of ceramic base body 12. Typically, terminal 16 extends from second surface 12b. Terminal 16 is not particularly limited as long as it is a conductive member. It can be made of a metal such as molybdenum or nickel, but is preferably made of molybdenum from the perspective of thermal expansion coefficient.

[0089] In addition to the above-mentioned internal electrodes 14 and second internal electrodes 15, other electrodes may be embedded in the ceramic base body 12. Examples of such other electrodes include heater electrodes and ESC electrodes (electrostatic discharge electrodes).

Claims

1. A ceramic base, wherein: have: a ceramic base body having a first surface on which a wafer is placed and a second surface opposite to the first surface; an internal electrode, the internal electrode being implanted in the ceramic base body; as well as a terminal having one end connected to the internal electrode and the other end reaching the second surface of the ceramic base body, The internal electrode includes: a horizontal portion arranged parallel to the first surface, and a non-horizontal portion extending from the horizontal portion toward the first surface or the second surface. The horizontal portion and the non-horizontal portion are formed integrally by bending a piece of electrode, so that there is a bent portion forming a boundary between the horizontal portion and the non-horizontal portion.

2. The ceramic susceptor according to claim 1, wherein: The internal electrode is composed of a metal mesh.

3. The ceramic susceptor according to claim 1, wherein: The angle formed by the horizontal portion and the non-horizontal portion at the bending portion is 50 to 130 degrees.

4. The ceramic susceptor according to claim 1 or 2, wherein: The number of the non-horizontal parts is 1 to 100.

5. The ceramic susceptor according to claim 1 or 2, wherein: The ceramic base body is made of aluminum nitride and / or aluminum oxide.

6. The ceramic susceptor according to claim 1 or 2, wherein: The single electrode includes a disk-shaped electrode main portion and an extension portion extending from the electrode main portion. The electrode main portion constitutes the horizontal portion, and the extension portion is bent to constitute the non-horizontal portion.

7. The ceramic susceptor according to claim 1 or 2, wherein: The one electrode has a disk-shaped electrode main portion and an extension portion extending from the electrode main portion. A pair of cutouts are formed in a portion of the electrode main portion corresponding to the base of the extension portion so as to enable bending at a position further inward than the outer periphery of the electrode main portion. The electrode is bent at a position inside the electrode main part in a form including a root portion defined by the pair of cutouts, so that the extension portion and the root portion constitute the non-horizontal portion, and the remaining portion of the electrode main part except the root portion constitutes the horizontal portion.

8. The ceramic susceptor according to claim 1 or 2, wherein: The non-horizontal portion of the internal electrode reaches the first surface.

9. The ceramic susceptor according to claim 8, wherein: The internal electrode functions as a ground electrode.

10. The ceramic susceptor according to claim 9, wherein: The ceramic susceptor is used in an ion implantation apparatus or a physical vapor deposition (PVD) apparatus.

11. The ceramic susceptor according to claim 1 or 2, wherein: The ceramic base body includes: a first disk-shaped layer constituting the first surface; and a second disk-shaped layer having a larger diameter than the first layer and constituting the second surface, wherein the second layer extends along the outer circumference of the ceramic base body beyond the outer circumferential end of the first layer to form an outer peripheral step portion. The ceramic base further includes a second internal electrode that is implanted in the outer peripheral step portion of the second layer and connected to the internal electrode.

12. The ceramic susceptor according to claim 11, wherein: The internal electrode includes the horizontal portion implanted in the first layer and the non-horizontal portion implanted in the first layer and the second layer. The second internal electrode is implanted in the outer peripheral portion of the second layer including the outer peripheral step portion in parallel with the horizontal portion, and is connected to a lower end of the non-horizontal portion.

13. The ceramic susceptor according to claim 11, wherein: The internal electrode and the second internal electrode are separate electrodes.

14. The ceramic susceptor according to claim 11, wherein: The internal electrode and the second internal electrode are integrally formed by bending a single electrode.

15. The ceramic susceptor according to claim 11, wherein The ceramic susceptor is used in a film forming apparatus or an etching apparatus using plasma.

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