Multi-section ceramic heater

Abstract

The invention provides a multi-section ceramic heater capable of suppressing breakage and realizing good soaking performance. The ceramic heater is provided with: a ceramic plate including an inner section and an outer section; an inner section heater circuit implanted in the inner section; an outer section heater circuit implanted in the outer section at a different depth position from the inner section heater circuit; a pair of first power supply terminals for supplying power to the inner section heater circuit; a pair of second power supply terminals for supplying power to the outer section heater circuit; and a pair of jumpers embedded in the inner section of the ceramic plate, one of the jumpers connecting one of the second power supply terminals and the outer section heater circuit at a first connection portion, and the other of the jumpers connecting the other of the second power supply terminals and the outer section heater circuit at a second connection portion at a position different from the first connection portion. The inner section heater circuit, the outer section heater circuit, and the jumper wire are each configured from a resistive heating element. The thickness of the jumper wire is 1.2-3.0 times the thickness of the heater circuit in the outer section.

Description

Technical Field

[0001] This invention relates to multi-segment ceramic heaters. Background Technology

[0002] In film deposition apparatuses used in semiconductor manufacturing processes, ceramic heaters are used as support stages for uniformly controlling wafer temperature. Among these ceramic heaters, ceramic heaters comprising a ceramic plate for wafer placement and a cylindrical ceramic shaft mounted on that plate are widely used. Additionally, multi-section ceramic heaters having multiple heating zones are also known.

[0003] Patent Document 1 (Japanese Patent Application Publication No. 2020-191315) discloses a heating device that includes a first heater electrode disposed in a generally circular first region within a plate-shaped component, and a second heater electrode disposed in a generally annular second region surrounding the first heater electrode. The heating device also includes a universal drive electrode electrically connected to all of the plurality of heater electrodes and electrically connected to a universal power supply terminal. This universal drive electrode has a thicker portion than other portions of the universal drive electrode. In other words, the thickness of the universal drive electrode is disclosed to be locally different within its surface.

[0004] Patent Document 2 (Japanese Patent Application Publication No. 2015-191837) discloses a stacked heating element having an inner heater and an outer heater surrounding the inner heater. This stacked heating element comprises: a ceramic main body; a heater built into the main body; a terminal mounted at one end of the main body in the thickness direction; and a power supply path supplying power from the terminal to the heater. The power supply path is composed of a combination of multiple conductive layers disposed within the main body and multiple through-holes. One of the multiple conductive layers, a conductive layer X located closer to the terminal than the heater, has a connection portion P with a through-hole α and a connection portion Q with a through-hole β, and includes at least a portion of the path connecting the connection portion P and the connection portion Q. This conductive layer X has a region AX with a film thickness greater than its surrounding area.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-191315

[0008] Patent Document 2: Japanese Patent Application Publication No. 2015-191837 Summary of the Invention

[0009] For ceramic heaters, a small in-plane temperature difference (i.e., uniform heat distribution) is required for the wafer placement area. In particular, with the miniaturization and high integration of processes in recent years, even better uniform heat distribution is demanded in ceramic heaters. From this perspective, it is desirable to minimize the temperature difference between locations with and without resistive heating elements. To this end, it is preferable to arrange resistive heating elements throughout the entire area of ​​the ceramic heater; printed resistive heating elements are a promising alternative. However, in multi-segment ceramic heaters with a ceramic shaft positioned in the center of a ceramic plate containing thin resistive heating elements, localized hot or cold spots easily arise in the electrical connection paths (jump wire connections) of the resistive heating elements from the center of the plate towards the outer periphery due to the heat generated by the electrical connection paths themselves. This deteriorates the overall uniform heat distribution of the plate containing the multi-segment ceramic heater.

[0010] The inventors of this invention recently discovered that in a multi-segment ceramic heater comprising an inner segment heater circuit, an outer segment heater circuit, and a jumper, by making the thickness of the jumper circuit within the range of 1.2 to 3.0 times the thickness of the outer segment heater circuit, breakage during manufacturing and other processes can be suppressed, and good heat uniformity can be achieved.

[0011] Therefore, the object of the present invention is to provide a multi-segment ceramic heater that can suppress breakage during manufacturing and achieve good heat uniformity.

[0012] According to the present invention, the following solution is provided.

[0013] [Option 1]

[0014] A multi-segment ceramic heater, comprising:

[0015] A ceramic plate, which is a circular plate having a first surface for placing a wafer and a second surface facing the first surface, wherein, when viewed from above, the ceramic plate includes: an inner segment of a circular region defined as being within a defined distance from the center of the ceramic plate, and an outer segment of an annular region defined as being outside the inner segment;

[0016] An inner section heater circuit is embedded in the inner section of the ceramic plate parallel to the first surface;

[0017] An outer section heater circuit is embedded in the outer section of the ceramic plate at a depth position different from that of the inner section heater circuit, parallel to the first surface.

[0018] A pair of first power supply terminals are disposed in the center of the inner section of the ceramic plate and are used to supply power to the heater circuit of the inner section.

[0019] A pair of second power supply terminals, located at the center of the inner section of the ceramic plate, are used to supply power to the heater circuit of the outer section; and

[0020] A pair of jumpers, which are separate pairs of jumpers embedded in the inner section of the ceramic plate at the same depth as the outer section heater circuit and parallel to the first surface, respectively. One of the jumpers electrically connects one of the second power supply terminals to the outer section heater circuit at a first connection portion, and the other jumper electrically connects the other of the second power supply terminals to a second connection portion of the outer section heater circuit at a different location from the first connection portion.

[0021] The inner section heater circuit, the outer section heater circuit, and the jumper are all thin components made of resistive heating elements selected from the group consisting of printed patterns, foil, perforated metal, and mesh.

[0022] The thickness of the jumper is 1.2 to 3.0 times the thickness of the outer section heater circuit.

[0023] [Option 2]

[0024] According to the multi-section ceramic heater described in Scheme 1, wherein,

[0025] The outer section is composed of multiple outer sub-sections divided into arcs. Between adjacent outer sub-sections in the circumferential direction, there is no linear boundary region where the heater circuit of the outer section exists along the radial direction of the ceramic plate without completely cutting off the outer section.

[0026] The outer section heater circuit is configured to: start from the first connection in one or two directions, pass through each of the multiple outer sub-sections in a single stroke across approximately the entire area in each starting direction, and snake along the circumferential direction, alternating between circumferential travel and folding back in front of the dividing area, and reach the second connection.

[0027] [Option 3]

[0028] According to the multi-section ceramic heater described in Scheme 2, wherein...

[0029] When viewed from above, the first connecting portion and the second connecting portion are respectively configured such that the dividing region and the connecting portion are separated by an angle of 20° or more between a straight line passing through the center of the dividing region in the circumferential direction closest to the connecting portion and the center of the ceramic plate, and a straight line passing through the center of the connecting portion in the circumferential direction and the center of the ceramic plate.

[0030] [Option 4]

[0031] According to any one of Schemes 1 to 3, the multi-section ceramic heater wherein...

[0032] When the first connecting portion and the second connecting portion are respectively regarded as arcs constituting the outer circumference of the inner section, the central angle of each arc is in the range of 6.0 to 10.0°.

[0033] [Option 5]

[0034] According to any one of Schemes 1 to 4, the multi-segment ceramic heater, wherein...

[0035] The outer section heater circuit is configured such that it starts from the first connecting part in one direction and reaches the second connecting part in one stroke to form a series circuit.

[0036] [Option 6]

[0037] According to any one of Schemes 1 to 4, the multi-segment ceramic heater, wherein...

[0038] The outer section heater circuit is configured such that it starts from the first connecting part in two directions and reaches the second connecting part in one stroke in each direction to form a parallel circuit.

[0039] [Option 7]

[0040] According to any one of Schemes 1 to 6, the multi-segment ceramic heater, wherein,

[0041] When viewed from above, the pair of jumpers and the pair of second power supply terminals are configured to be symmetrical about the perpendicular bisector of the line segment connecting the pair of second power supply terminals.

[0042] [Option 8]

[0043] According to any one of Schemes 1 to 7, the multi-section ceramic heater, wherein,

[0044] The inner section heater circuit, the outer section heater circuit, and the jumper wire are respectively the shapes of the printed patterns.

[0045] [Option 9]

[0046] According to any one of Schemes 1 to 8, the multi-section ceramic heater, wherein,

[0047] The thickness of the outer section heater circuit is constant in the in-plane direction, and the thickness of the jumper is also constant in the in-plane direction.

[0048] [Option 10]

[0049] According to any one of Schemes 1 to 9, the multi-segment ceramic heater, wherein...

[0050] The multi-segment ceramic heater further comprises: an RF electrode and / or an ESC electrode embedded in the ceramic plate at a depth position closer to the first surface than the inner segment heater circuit and the jumper.

[0051] [Option 11]

[0052] According to any one of Schemes 1 to 10, the multi-segment ceramic heater, wherein,

[0053] The ceramic plate contains aluminum nitride or aluminum oxide.

[0054] [Option 12]

[0055] According to any one of Schemes 1 to 11, the multi-segment ceramic heater, wherein,

[0056] The multi-segment ceramic heater further comprises: a cylindrical ceramic shaft that is concentrically mounted on the second surface of the ceramic plate and has an internal space.

[0057] [Option 13]

[0058] According to any one of Schemes 1 to 12, the multi-segment ceramic heater, wherein,

[0059] The resistive heating element comprises at least one selected from the group consisting of tungsten, molybdenum, tungsten-molybdenum alloy, tungsten carbide, tungsten carbide-titanium nitride composite material, and tungsten carbide-alumina composite material.

[0060] [Option 14]

[0061] According to any one of Schemes 1 to 13, the multi-segment ceramic heater, wherein,

[0062] The thickness of the jumper wire is 1.8 to 3.0 times the thickness of the outer section heater circuit. Attached Figure Description

[0063] Figure 1 This is a simplified top view illustrating an example of the multi-segment ceramic heater of the present invention.

[0064] Figure 2 It is shown Figure 1 The diagram shown is a simplified cross-sectional view of a multi-section ceramic heater.

[0065] Figure 3 This is a simplified top view diagram used to illustrate a series circuit of a multi-segment ceramic heater.

[0066] Figure 4 This is a simplified top view diagram used to illustrate a parallel circuit of a multi-segment ceramic heater.

[0067] Figure 5 This is a simplified top view showing another example of a multi-segment ceramic heater, corresponding to Example 1.

[0068] Figure 6 This is a simplified top view showing another example of a multi-segment ceramic heater, corresponding to Examples 2 and 10.

[0069] Figure 7 This is a simplified top view showing another example of a multi-segment ceramic heater, corresponding to Examples 3 and 5.

[0070] Figure 8 This is a simplified top view showing another example of a multi-segment ceramic heater, corresponding to Examples 4, 7 and 8.

[0071] Figure 9 This is a simplified top view showing another example of a multi-segment ceramic heater, corresponding to Example 6.

[0072] Figure 10 This is a simplified top view of an example of a multi-section ceramic heater, corresponding to Example 9 (Comparative Example).

[0073] Figure 11 It is shown Figure 10 The schematic cross-sectional view of the multi-segment ceramic heater shown corresponds to Example 9 (Comparative Example). Detailed Implementation

[0074] The multi-segment ceramic heater of the present invention is a ceramic platform used to support wafers within a semiconductor manufacturing apparatus. Typically, the ceramic heater of the present invention can be a ceramic heater for a semiconductor film deposition apparatus. Typical examples of film deposition apparatuses include: CVD (chemical vapor deposition) apparatuses (e.g., thermal CVD apparatuses, plasma CVD apparatuses, photoCVD apparatuses, and MOCVD apparatuses) and PVD (physical vapor deposition) apparatuses.

[0075] Figure 1 and Figure 2 The diagram shows one scheme for a multi-segment ceramic heater. Figure 1 and Figure 2The multi-segment ceramic heater 10 shown includes: a ceramic plate 12, an inner segment heater circuit 14, an outer segment heater circuit 16, a pair of first power supply terminals 18, a pair of second power supply terminals 20, and a pair of jumpers 22. The ceramic plate 12 is circular and has a first surface 12a for mounting a wafer W and a second surface 12b opposite to the first surface 12a. In top view, the ceramic plate 12 includes: an inner segment Z1 defined as a circular region within a predetermined distance from the center of the ceramic plate 12, and an outer segment Z2 defined as an annular region outside the inner segment Z1. An inner section heater circuit 14 is embedded in the inner section Z1 of the ceramic plate 12, parallel to the first surface 12a. Conversely, an outer section heater circuit 16 is embedded in the outer section Z2 of the ceramic plate 12 at a different depth than the inner section heater circuit 14, parallel to the first surface 12a. A pair of first power supply terminals 18 are used to supply power to the inner section heater circuit 14, and they are located at the center of the inner section Z1 of the ceramic plate 12. A pair of second power supply terminals 20 are used to supply power to the outer section heater circuit 16, and they are also located at the center of the inner section Z1 of the ceramic plate 12. A pair of jumpers 22 are separated from each other and are embedded in the inner section Z1 of the ceramic plate 12 at the same depth as the outer section heater circuit 16, parallel to the first surface 12a. One of the jumpers 22 electrically connects one of the second power supply terminals 20 to the outer section heater circuit 16 at the first connection portion 24, while the other jumper 22 electrically connects the other of the second power supply terminals 20 to the outer section heater circuit 16 at a second connection portion 26 at a different position from the first connection portion 24. The inner section heater circuit 14, the outer section heater circuit 16, and the jumpers 22 are all thin components made of resistive heating elements, selected from the group consisting of printed patterns, foil, perforated metal, and mesh. Furthermore, the thickness of the jumper 22 is 1.2 to 3.0 times the thickness of the outer section heater circuit 16. In this way, in the multi-segment ceramic heater 10 which includes an inner section heater circuit 14, an outer section heater circuit 16 and a jumper 22, by making the thickness of the jumper 22 within the range of 1.2 to 3.0 times the thickness of the outer section heater circuit 16, it is possible to suppress breakage during manufacturing and achieve good heat uniformity.

[0076] As described above, with the miniaturization and high integration of processes in recent years, ceramic heaters are required to have better heat uniformity (e.g., a maximum in-plane temperature difference of less than 1°C). Therefore, it is preferable to arrange resistance heating elements throughout the entire area of ​​the ceramic heater, and printed resistance heating elements are a promising candidate. However, in multi-segment ceramic heaters with a ceramic shaft arranged in the center of a ceramic plate in which a thin resistance heating element (e.g., less than 100 μm thick) is embedded, local hot or cold spots are easily generated in the electrical connection path (jump wire connection) of the resistance heating element from the center of the plate toward the outer periphery of the plate due to the heat generated by the electrical connection path itself. There is a problem that the overall heat uniformity of the multi-segment ceramic heater plate is deteriorated due to this effect. In this regard, according to the present invention, by making the thickness of the jumper 22 more than 1.2 times the thickness of the outer segment heater circuit 16, the above-mentioned heat uniformity can be improved. This is because by making the jumper 22 thicker than the outer section heater circuit 16, the resistance of the jumper 22, which is also composed of resistive heating elements like the inner section heater circuit 14 and the outer section heater circuit 16, is reduced. As a result, the heat generated by the jumper 22 can be suppressed to a lower level, reducing local hot spots. However, it is undesirable for the jumper 22 to be too thick compared to the outer section heater circuit 16. For example, if the thickness of the jumper 22 exceeds three times (e.g., more than four times) the thickness of the outer section heater circuit 16, a large step will be created at the thickness change of the resistive heating element at the connection between the jumper 22 and the outer section heater circuit 16 (i.e., the first connection 24 and the second connection 26). Stress may concentrate at this step and cause it to break. The stress concentration at this step and the resulting breakage are likely to occur during the manufacturing process of the ceramic heater (especially when firing the ceramic plate and joining the ceramic shaft to the ceramic plate). In addition, it is also envisioned that the ceramic heater will breakage during use (i.e., during the operation of the semiconductor manufacturing device). For example, in the former case, the stress generated during the ceramic plate forming process amplifies during the ceramic plate firing process, and the stress tends to concentrate in the step portion. Conversely, in the latter case, due to exposure to high temperatures during the operation of the semiconductor manufacturing apparatus, the thermal expansion of the ceramic plate easily causes stress concentration in the step portion. In this regard, by making the thickness of the jumper 22 less than 3.0 times the thickness of the outer section heater circuit 16, damage caused by stress concentration can be effectively suppressed. Based on the above reasons, the thickness of the jumper 22 is 1.2 to 3.0 times the thickness of the outer section heater circuit 16, preferably 1.3 to 2.8 times, more preferably 1.4 to 2.5 times, and even more preferably 1.5 to 2.0 times.

[0077] When viewing the ceramic plate 12 from above, the area of ​​the jumper 22 is preferably 30-80% of the area of ​​the inner section Z1, more preferably 35-80%, and even more preferably 40-80%. If the jumper 22 has such a large area, the resistance decreases, thus suppressing the heat generated by the jumper 22 and contributing to improved heat uniformity. Typically, when a step exists within the surface of the electrical connection path including the large-area jumper 22, it is prone to becoming a stress source and causing breakage. In this regard, as described above, in this invention, by making the thickness of the jumper 22 less than 3.0 times the thickness of the outer section heater circuit 16, such stress-induced breakage can be effectively suppressed.

[0078] From the viewpoints of excellent thermal conductivity, high electrical insulation, and thermal expansion characteristics close to those of silicon, the main part (i.e., the ceramic substrate) of the ceramic plate 12, excluding the implanted components such as the inner section heater circuit 14, the outer section heater circuit 16, and the jumper 22, preferably contains aluminum nitride or aluminum oxide, and more preferably aluminum nitride.

[0079] The ceramic plate 12 is circular. However, the top view of the circular ceramic plate 12 does not need to be a complete circle; for example, it can be an incomplete circle missing a portion, such as an orientation flat. The size of the ceramic plate 12 can be appropriately determined based on the assumed diameter of the wafer used, and is not particularly limited. In the case of a circle, the diameter is typically 150 to 450 mm, for example, around 300 mm.

[0080] Viewed from above, the ceramic plate 12 includes an inner section Z1 and an outer section Z2. The inner section Z1 is defined as a circular area within a specified distance from the center of the ceramic plate 12. The outer section Z2 is defined as an annular area outside the inner section Z1. The outer section Z2 is composed of multiple outer sub-sections Z2a, Z2b, Z2c, and Z2d divided into arcs, which is ideal for easily accommodating the outer section heater circuit 16 throughout the entire area of ​​the outer section Z2. The outer section Z2 may also have two or more concentric annular areas of different sizes that do not overlap. In this case, the outer section Z2 has at least a first outer section close to the inner section Z1 and a second outer section located outside the first outer section. If necessary, a third or more outer sections may exist outside the second outer section.

[0081] The inner section heater circuit 14 is embedded in the inner section Z1 of the ceramic plate 12 parallel to the first surface 12a. A pair of first power supply terminals 18 for supplying power to the inner section heater circuit 14 are provided at the center of the inner section Z1 of the ceramic plate 12. Preferably, the first power supply terminals 18 are connected to both ends of the inner section heater circuit 14. There may also be two or more pairs of first power supply terminals 18. The first power supply terminals 18 are rod-shaped, and the inner section heater circuit 14 is connected to the heater power supply (not shown) via the rod-shaped first power supply terminals 18.

[0082] The outer section heater circuit 16 is implanted in the outer section Z2 of the ceramic plate 12 at a different depth position than the inner section heater circuit 14, parallel to the first surface 12a. Figure 2 In the inner section heater circuit 14, the inner section heater circuit 14 is implanted at a position higher than the outer section heater circuit 16 (i.e., at a depth close to the first surface 12a), but it is not limited to this. Therefore, the inner section heater circuit 14 can also be implanted at a position lower than the outer section heater circuit 16 (i.e., at a depth close to the second surface 12b). A pair of second power supply terminals 20 for supplying power to the outer section heater circuit 16 is provided at the center of the inner section Z1 of the ceramic plate 12 (however, at a different position than the first power supply terminal 18). The pair of second power supply terminals 20 is positioned away from the outer section heater circuit 16, and therefore, the pair of second power supply terminals 20 is electrically connected to the outer section heater circuit 16 via a pair of jumpers 22. There can be more than two pairs of second power supply terminals 20. The second power supply terminals 20 are rod-shaped, and the outer section heater circuit 16 is connected to the heater power supply (not shown) via the jumpers 22 and the rod-shaped second power supply terminals 20.

[0083] The outer section heater circuit 16 can be either a series circuit or a parallel circuit. That is, as shown below... Figure 3 As shown in the diagram, along with arrows indicating the direction of current, the outer section heater circuit 16 is configured such that it extends from the first connection 24 in one direction to the second connection 26 in a single stroke, forming a series circuit. In this case, it is preferable to have the first connection 24 and the second connection 26 respectively located at both ends of the outer section heater circuit 16. Alternatively, as... Figure 4 As shown in the diagram along with the arrows indicating the direction of current, the outer section heater circuit 16 can be configured such that it starts from the first connection 24 in two directions and reaches the second connection 26 in a single stroke in each direction, forming a parallel circuit. In this case, it is preferable to arrange the first connection 24 and the second connection 26 at the starting or ending points of the outer section heater circuit 16, respectively. Figure 1The outer section heater circuit 16 shown corresponds to this parallel circuit. From the viewpoint of uniform heating, series and parallel circuits are equivalent; however, from the viewpoint of preventing an increase in resistance, the outer section heater circuit 16 is preferably a parallel circuit. In the case of a parallel circuit, a resistance value close to that of the spiral resistive heating element used in conventional ceramic heaters can be achieved.

[0084] A pair of jumpers 22 are embedded in the inner section Z1 of the ceramic plate 12 at the same depth as the outer section heater circuit 16, parallel to the first surface 12a. The pair of jumpers 22 are separate; one jumper 22 electrically connects one of the second power supply terminals 20 to the outer section heater circuit 16 at the first connection portion 24, while the other jumper 22 electrically connects the other of the second power supply terminals 20 to the outer section heater circuit 16 at a second connection portion 26 at a different location from the first connection portion 24. There may be two or more pairs of jumpers 22. Preferably, the first connection portion 24 and the second connection portion 26 are respectively arranged at both ends of the outer section heater circuit 16.

[0085] The pair of jumpers 22 and the pair of second power supply terminals 20 are preferably configured such that, when viewed from above, they are symmetrical about the perpendicular bisector of the line segment connecting the pair of second power supply terminals 20. This configuration ensures that the power supply path length from the pair of second power supply terminals 20 through the pair of jumpers 22 toward the outer section of the heater circuit 16 is equal, making it easier to achieve even better heat distribution.

[0086] As described above, the inner section heater circuit 14, the outer section heater circuit 16, and the jumper 22 are all thin components made of resistive heating elements. The thin component is selected from the group consisting of printed patterns, foil, perforated metal, and mesh, and is particularly preferred to be a printed pattern. In the case of a thin component with a printed pattern, the inner section heater circuit 14, the outer section heater circuit 16, and the jumper 22 can be manufactured efficiently using printing while controlling the thickness. The thickness of the thin component made of resistive heating elements is preferably 100 μm or less, more preferably 10 to 100 μm, and even more preferably 10 to 60 μm. If the thickness is 10 μm or more, thickness deviations are less likely to occur when forming the thin component using printing or the like. The resistive heating element constituting the thin component can be any resistive heating element commonly used in ceramic heaters, and there is no particular limitation. Preferred examples of resistive heating elements include: tungsten, molybdenum, tungsten-molybdenum alloys, tungsten carbide, tungsten carbide-titanium nitride composites, tungsten carbide-alumina composites, and combinations thereof.

[0087] Preferably, the thickness of the outer section heater circuit 16 and the jumper 22 are constant in the in-plane direction. In this specification, "the thickness of the outer section heater circuit 16 or jumper 22 is constant in the in-plane direction" means that the thickness of the outer section heater circuit 16 or jumper 22 is not intentionally altered locally. Therefore, it is not necessary for the thickness to be completely constant in the in-plane direction; if the thickness is approximately constant to a degree that is considered not to have been intentionally altered (e.g., a thickness deviation of 5% or less), it can also be considered "the thickness is constant in the in-plane direction." Here, the thickness deviation is calculated as the difference between the maximum and minimum thickness values ​​divided by the average thickness and multiplied by 100. By making the thickness of the resistive heating element constant in the in-plane direction in both the outer section heater circuit 16 and the jumper 22, the resistance unevenness caused by thickness variations can be eliminated, achieving good heat uniformity. As a result, the effect obtained by making the thickness of jumper 22 1.2 to 3.0 times the thickness of the outer section heater circuit 16 (i.e., breakage suppression and good heat uniformity) can be achieved more effectively. In this sense, the thickness of the inner section heater circuit 14 is also preferably constant in the in-plane direction. In this respect, since the inner section heater circuit 14, the outer section heater circuit 16, and jumper 22 are all thin components made of resistive heating elements such as printed patterns, it is suitable to keep their respective thicknesses constant in the in-plane direction.

[0088] The outer section Z2 is preferably composed of multiple outer sub-sections Z2a, Z2b, Z2c, and Z2d, which are divided into arc shapes. In this case, it is preferable that the outer section heater circuit 16 does not cross the linear boundary region B between adjacent outer sub-sections Z2a, Z2b, Z2c, and Z2d in the circumferential direction, so as not to completely cut off the outer section Z2 along the radial direction of the ceramic plate 12. The outer section heater circuit 16 is preferably configured to start from the first connecting part 24 in one or two directions, pass through the outer sub-sections Z2a, Z2b, Z2c, and Z2d in a single stroke in each starting direction, and snake along the circumferential direction and back to the boundary region B, and reach the second connecting part 26. In this way, the outer section heater circuit 16 can be arranged in the entire area of ​​the outer section Z2. That is, the outer section heater circuit 16 is arranged in the entire area of ​​each of the outer sub-sections Z2a, Z2b, Z2c, and Z2d. Furthermore, the outer section heater circuit 16 can also be arranged in the portion between the outer sub-sections Z2a, Z2b, Z2c, and Z2d that is not shielded by the boundary region B. The outer section heater circuit 16 can be arranged on the entire surface of the ceramic plate 12 in the form of continuous wiring from the first connecting portion 24 to the second connecting portion 26 in each of the outer sub-sections Z2a, Z2b, Z2c, and Z2d. In this scheme, the outer section heater circuit 16 can also be either a series circuit or a parallel circuit, as described above. Preferably, it is a parallel circuit that allows the resistance value of the outer section heater circuit 16 to be smaller than that of a series circuit.

[0089] In the above-described scheme with outer sub-segments Z2a, Z2b, Z2c, and Z2d, it is preferable that the circumferential positions of the first connecting portion 24 and the second connecting portion 26 are not the same as the circumferential position of the boundary region B. This makes it less prone to localized hot spots and achieves better heat uniformity. Specifically, as... Figure 1As shown, when viewing the ceramic plate 12 from above, the first connecting portion 24 and the second connecting portion 26 are preferably configured such that the boundary region B and the connecting portion 24 or 26 are separated by an angle θ1 (hereinafter referred to as the deflection angle θ1) formed by a straight line L1 passing through the center of the boundary region B closest to the connecting portion 24 or 26 in the circumferential direction and the center of the ceramic plate 12, and a straight line L2 passing through the center of the connecting portion 24 or 26 in the circumferential direction and the center of the ceramic plate. It should be noted that when there are multiple candidates for straight lines L1 and / or L2, the straight lines L1 and L2 are determined to obtain the minimum deflection angle θ1. The deflection angle θ1 is 20° or more, preferably 30° or more, more preferably 40° or more, further preferably 45° or more, and particularly preferably 45 to 90°. In other words, the deflection angle θ1 is the angle of deflection of the center of the connecting portion 24 or 26 in the circumferential direction relative to the centerline of the boundary region B extending in the radial direction.

[0090] When the first connecting portion 24 and the second connecting portion 26 are each considered as arcs constituting the outer circumference of the inner section Z1, the central angle θ2 of each arc is preferably in the range of 6.0 to 10.0°, more preferably 6.0 to 8.0°. Accordingly, with an offset angle θ1 within the above range, the circumferential positions of the first connecting portion 24 and the second connecting portion 26 can be reliably not aligned with the circumferential position of the boundary region B, thereby more effectively achieving better heat uniformity.

[0091] The ceramic plate 12 may further include an RF electrode 30 and / or an ESC electrode. In this case, the RF electrode 30 and / or the ESC electrode are preferably embedded at a depth of the ceramic plate 12 closer to the first surface 12a than the inner section heater circuit 14 and jumper 22. By applying a high frequency to the RF electrode, film deposition can be performed using a plasma CVD process. The ESC electrode is short for electrostatic chuck (ESC) electrode, also known as an electrostatic electrode. When a voltage is applied to the ESC electrode by an external power source, the wafer placed on the surface of the ceramic plate 12 is held by the Johnson-Labec force. The ESC electrode is preferably a thin, circular electrode with a diameter slightly smaller than that of the ceramic plate 12, for example, it can be a mesh electrode made by braiding fine metal wires into a mesh and forming a sheet. The ESC electrode can be used as a plasma electrode. That is, by applying a high frequency to the ESC electrode, it can also be used as an RF electrode, and film deposition can also be performed using a plasma CVD process. An RF terminal 32 or an ESC terminal for power supply is connected to the RF electrode 30 or the ESC electrode. The RF terminal 32 or ESC terminal is rod-shaped, and the RF electrode 30 or ESC electrode is connected to an external power supply (not shown) via the rod-shaped RF terminal 32 or ESC terminal.

[0092] Ideally, the ceramic shaft 28 can be mounted concentrically on the second surface 12b of the ceramic plate 12. The ceramic shaft 28 is a cylindrical component with an internal space S, and can have the same configuration as ceramic shafts used in known ceramic bases or ceramic heaters. The internal space S is configured such that terminal bars such as the first power supply terminal 18, the second power supply terminal 20, and the RF terminal 32 pass through it. The ceramic shaft 28 is preferably made of the same ceramic material as the ceramic plate 12. Therefore, the ceramic shaft 28 preferably contains aluminum nitride or aluminum oxide, more preferably aluminum nitride. The upper end face of the ceramic shaft 28 is preferably joined to the second surface 12b of the ceramic plate 12 using solid-state bonding or diffusion bonding. The outer diameter of the ceramic shaft 28 is not particularly limited, for example, about 44 mm. The inner diameter of the ceramic shaft 28 (the diameter of the internal space S) is also not particularly limited, for example, about 39 mm.

[0093] Example

[0094] The invention will be further illustrated by the following examples. However, the invention is not limited to the following examples.

[0095] Example 1

[0096] (1) Fabrication of multi-segment ceramic heaters

[0097] Using the components given below, construct a device following known steps. Figure 2 The cross-sectional structure shown and Figure 5 The multi-segment ceramic heater 10 is shown in the planar configuration and meets the conditions shown in Table 1.

[0098] <Components and their specifications>

[0099] • Ceramic plate 12: A circular plate-shaped sintered aluminum nitride body (diameter: 340 mm, thickness: 18 mm) (with an inner section heater circuit 14, an outer section heater circuit 16, a jumper wire 22, and an RF electrode 30 embedded inside)

[0100] • Ceramic Shaft 28: Cylindrical aluminum nitride sintered body (height: 170mm, outer diameter: 45mm, inner diameter: 39mm)

[0101] • Inner section Z1: A circular area with a diameter of 240mm located in the center of ceramic plate 12.

[0102] • Outer section Z2: The annular region outside the inner section Z1 in the ceramic plate 12, which has four outer sub-sections Z2a, Z2b, Z2c, and Z2d divided by a linear boundary region B extending in the radial direction.

[0103] • Inner section heater circuit 14: implanted at a depth of 6 mm, measured from the first surface 12a of the inner section Z1. Figure 5 The printed pattern of the resistive heating element shown

[0104] • Outer section heater circuit 16: implanted at a depth of 12mm, measured from the first surface 12a of the outer section Z2. Figure 5 The printed pattern shown is of a parallel circuit composed of resistive heating elements. The deflection angle θ1 of the first connecting portion 24 and the second connecting portion 26 relative to the boundary region B is 20°.

[0105] • Jumper wire 22: Implanted at a depth of 12mm, measured from the first surface 12a of the inner segment Z1. Figure 5 The printed pattern shown is a symmetrical design composed of resistive heating elements (thickness ratio and area ratio are shown in Table 1).

[0106] • Resistive heating element: Tungsten carbide-titanium nitride composite material (commonly used in the inner section heater circuit 14, the outer section heater circuit 16, and jumper 22)

[0107] • RF electrode 30: A molybdenum electrode layer implanted at a depth of 1 mm, measured from the first surface 12a of the ceramic plate 12.

[0108] • First power supply terminal 18: Two nickel-plated terminal bars

[0109] • Second power supply terminal 20: Two nickel-plated terminal bars

[0110] • RF terminal 32: A nickel-plated terminal bar

[0111] • First connecting part 24 and second connecting part 26: Arc-shaped portions with a central angle θ2 of 6.0° (end of jumper 22)

[0112] The ceramic plate 12, which internally incorporates the inner section heater circuit 14, the outer section heater circuit 16, jumpers 22, and RF electrodes 30, is fabricated according to the following steps. First, two circular aluminum nitride sintered bodies are prepared. The inner section heater circuit 14 is printed on one aluminum nitride sintered body using a prescribed pattern. The other aluminum nitride sintered body... Figure 5 The pattern shown is printed on the outer section heater circuit 16 and jumper 22. At this time, the thicknesses of jumper 22 and outer section heater circuit 16 are controlled such that the ratio of the thickness of jumper 22 to the thickness of the outer section heater circuit 16 after firing is 1.2. Next, aluminum nitride powder and RF electrode 30 are pressed and molded to obtain aluminum nitride pressed powder with RF electrode 30 internally embedded. This aluminum nitride pressed powder and the aluminum nitride sintered body with the above-described printed pattern are then... Figure 2The layered structures shown are stacked and pressed into shape. The resulting pressed body (layer) is fired at 1750-1850°C for 3 hours under a nitrogen atmosphere to obtain a ceramic plate 12 with an inner section heater circuit 14, an outer section heater circuit 16, a jumper wire 22 and an RF electrode 30 embedded inside.

[0113] (2) Evaluation

[0114] A multi-segment ceramic heater 10 is placed inside the chamber of the film-forming apparatus. The chamber is evacuated and N2 gas is introduced to bring the N2 gas pressure inside the chamber to 5 Torr. Power is supplied to the inner segment heater circuit 14 and the outer segment heater circuit 16 via the first power supply terminal 18, the second power supply terminal 20, and the jumper 22, thereby heating the multi-segment ceramic heater 10 to a set temperature of 650°C. At this set temperature, the temperature distribution at the first surface 12a of the ceramic plate 12 is measured using an infrared camera. Based on the obtained temperature distribution mapping, the difference between the highest and lowest temperatures within the surface (i.e., the maximum temperature difference within the surface) is calculated as an indicator of heat uniformity. The results are shown in Table 1.

[0115] Example 2

[0116] like Figure 6 As shown in Table 1, the deflection angle θ1 of each center of the first connecting part 24 and the second connecting part 26 relative to the boundary region B was set to 0°. Otherwise, the multi-segment ceramic heater 10 was manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0117] Example 3

[0118] like Figure 7 As shown in Table 1, 1) the deflection angle θ1 of the first connecting part 24 and the second connecting part 26 relative to the boundary region B was set to 45°, and 2) the shape of the jumper wire was set to a vortex shape occupying 76% of the area of ​​the inner section Z1. Otherwise, the multi-section ceramic heater 10 was manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0119] Example 4

[0120] like Figure 8 As shown in Table 1, 1) the deflection angle θ1 of the first connecting part 24 and the second connecting part 26 relative to the boundary region B was set to 45°, and 2) the ratio of the thickness of the jumper wire 22 to the thickness of the outer section heater circuit 16 was set to 2.0. Otherwise, the multi-section ceramic heater 10 was manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0121] Example 5

[0122] like Figure 7 As shown in Table 1, the ratio of the thickness of jumper 22 to the thickness of the outer section heater circuit 16 was set to 2.0. Otherwise, the multi-section ceramic heater 10 was fabricated and evaluated in the same manner as in Example 3. The results are shown in Table 1.

[0123] Example 6

[0124] like Figure 9 As shown in Table 1, 1) the outer segment Z2 is divided into two outer sub-segments Z2a and Z2b by two boundary regions B extending along the radial direction; 2) the outer segment heater circuit 16 is configured as a series circuit; 3) the deflection angle θ1 of the first connecting part 24 and the second connecting part 26 relative to the boundary region B is set to 77°; 4) the ratio of the thickness of the jumper 22 to the thickness of the outer segment heater circuit 16 is set to 2.0. Otherwise, the multi-segment ceramic heater 10 is manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0125] Example 7

[0126] like Figure 8 As shown in Table 1, 1) the deflection angle θ1 of the first connecting part 24 and the second connecting part 26 relative to the boundary region B was set to 45°, and 2) the ratio of the thickness of the jumper wire 22 to the thickness of the outer section heater circuit 16 was set to 3.0. Otherwise, the multi-section ceramic heater 10 was manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0127] Example 8 (Compare)

[0128] like Figure 8 As shown in Table 1, 1) the deflection angle θ1 of the first connecting portion 24 and the second connecting portion 26 relative to the boundary region B was set to 45°, and 2) the ratio of the thickness of the jumper wire 22 to the thickness of the outer section heater circuit 16 was set to 4.0. Otherwise, a multi-section ceramic heater 10 was attempted to be manufactured in the same manner as in Example 1. However, as shown in Table 1, during the manufacturing process of the ceramic heater, damage occurred near the connection between the jumper wire 22 and the outer section heater circuit 16 (the stepped portion), impairing the function of the multi-section ceramic heater 10. Therefore, it was impossible to evaluate the heat uniformity. It is presumed that the stress generated during the ceramic plate forming process amplified during the ceramic plate firing process, causing stress concentration in the aforementioned stepped portion, leading to this damage.

[0129] Example 9 (Compare)

[0130] like Figure 10 , Figure 11As shown in Table 1, 1) the inner section heater circuit 14 is configured as a single-layer structure at the same depth as the outer section heater circuit 16 and jumper 22; 2) the outer section Z2 is divided into two outer sub-sections Z2a and Z2b by two boundary regions B extending in the radial direction; 3) the outer section heater circuit 16 is configured as a series circuit; 4) the pair of jumpers 22 are configured as two parallel narrow strips; 5) the deflection angle θ1 of the first connecting part 24 and the second connecting part 26 relative to the boundary region B is set to 0°; 6) the ratio of the thickness of the jumper 22 to the thickness of the outer section heater circuit 16 is set to 1.0. Otherwise, the multi-section ceramic heater 10 is manufactured and evaluated in the same manner as in Example 1. In this example, the multi-section ceramic heater 10, as... Figure 10 and Figure 11 As shown, the inner section heater circuit 14, the outer section heater circuit 16, and the jumper 22 are configured as a single-layer structure of the resistive heating element. Therefore, the inner section heater circuit 14 cannot be configured in the section where the jumper 22 is located. The results are shown in Table 1.

[0131] Example 10 (Compare)

[0132] like Figure 6 As shown in Table 1, 1) the deflection angle θ1 of the first connecting part 24 and the second connecting part 26 relative to the boundary region B was set to 0°, and 2) the ratio of the thickness of the jumper wire 22 to the thickness of the outer section heater circuit 16 was set to 1.0. Otherwise, the multi-section ceramic heater 10 was manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0133] Example 11 (Compare)

[0134] As shown in Table 1, 1) the deflection angle θ1 of the first connecting part 24 and the second connecting part 26 relative to the boundary region B was set to 20°, and 2) the ratio of the thickness of the jumper wire 22 to the thickness of the outer section heater circuit 16 was set to 1.0. Otherwise, the multi-section ceramic heater 10 was manufactured and evaluated in the same manner as in Example 3. The results are shown in Table 1.

[0135] Table 1

[0136]

Claims

1. A multi-segment ceramic heater, comprising: A ceramic plate, which is a circular plate having a first surface for placing a wafer and a second surface facing the first surface, wherein, when viewed from above, the ceramic plate includes an inner segment of a circular region defined as being within a defined distance from the center of the ceramic plate, and an outer segment of an annular region defined as being outside the inner segment. An inner section heater circuit is embedded in the inner section of the ceramic plate parallel to the first surface; An outer section heater circuit is embedded in the outer section of the ceramic plate at a depth position different from that of the inner section heater circuit, parallel to the first surface. A pair of first power supply terminals are disposed in the center of the inner section of the ceramic plate and are used to supply power to the heater circuit of the inner section. A pair of second power supply terminals, located at the center of the inner section of the ceramic plate, are used to supply power to the heater circuit of the outer section; and A pair of jumpers, which are separate pairs of jumpers embedded in the inner section of the ceramic plate at the same depth as the outer section heater circuit and parallel to the first surface, respectively. One of the jumpers electrically connects one of the second power supply terminals to the outer section heater circuit at a first connection portion, and the other jumper electrically connects the other of the second power supply terminals to a second connection portion of the outer section heater circuit at a different location from the first connection portion. The inner section heater circuit, the outer section heater circuit, and the jumper are all thin components made of resistive heating elements selected from the group consisting of printed patterns, foil, perforated metal, and mesh. The thickness of the jumper wire is 1.2 to 3.0 times the thickness of the outer section heater circuit.

2. The multi-segment ceramic heater according to claim 1, wherein, The outer section is composed of multiple outer sub-sections divided into arcs. Between adjacent outer sub-sections in the circumferential direction, there is no linear boundary region where the heater circuit of the outer section exists along the radial direction of the ceramic plate without completely cutting off the outer section. The outer section heater circuit is configured to: start from the first connection in one or two directions, pass through each of the multiple outer sub-sections in a single stroke across approximately the entire area in each starting direction, and snake along the circumferential direction, alternating between circumferential travel and folding back in front of the dividing area, and reach the second connection.

3. The multi-section ceramic heater according to claim 2, wherein, When viewed from above, the first connecting portion and the second connecting portion are respectively configured such that the dividing region and the connecting portion are separated by an angle of 20° or more between a straight line passing through the center of the dividing region in the circumferential direction closest to the connecting portion and the center of the ceramic plate, and a straight line passing through the center of the connecting portion in the circumferential direction and the center of the ceramic plate.

4. The multi-segment ceramic heater according to claim 2 or 3, wherein, When the first connecting portion and the second connecting portion are respectively regarded as arcs constituting the outer circumference of the inner section, the central angle of each arc is in the range of 6.0 to 10.0°.

5. The multi-segment ceramic heater according to claim 2 or 3, wherein, The outer section heater circuit is configured such that it starts from the first connecting part in one direction and reaches the second connecting part in one stroke to form a series circuit.

6. The multi-segment ceramic heater according to claim 2 or 3, wherein, The outer section heater circuit is configured such that it starts from the first connecting part in two directions and reaches the second connecting part in one stroke in each direction to form a parallel circuit.

7. The multi-segment ceramic heater according to any one of claims 1 to 3, wherein, When viewed from above, the pair of jumpers and the pair of second power supply terminals are configured to be symmetrical about the perpendicular bisector of the line segment connecting the pair of second power supply terminals.

8. The multi-segment ceramic heater according to any one of claims 1 to 3, wherein, The inner section heater circuit, the outer section heater circuit, and the jumper wire are respectively the shapes of the printed patterns.

9. The multi-segment ceramic heater according to any one of claims 1 to 3, wherein, The thickness of the outer section heater circuit is constant in the in-plane direction, and the thickness of the jumper is also constant in the in-plane direction.

10. The multi-segment ceramic heater according to any one of claims 1 to 3, wherein, The multi-segment ceramic heater further comprises: an RF electrode and / or an ESC electrode embedded in the ceramic plate at a depth position closer to the first surface than the inner segment heater circuit and the jumper.

11. The multi-segment ceramic heater according to any one of claims 1 to 3, wherein, The ceramic plate contains aluminum nitride or aluminum oxide.

12. The multi-segment ceramic heater according to any one of claims 1 to 3, wherein, The multi-segment ceramic heater further comprises: a cylindrical ceramic shaft that is concentrically mounted on the second surface of the ceramic plate and has an internal space.

13. The multi-segment ceramic heater according to any one of claims 1 to 3, wherein, The resistive heating element comprises at least one selected from the group consisting of tungsten, molybdenum, tungsten-molybdenum alloy, tungsten carbide, tungsten carbide-titanium nitride composite material, and tungsten carbide-alumina composite material.

14. The multi-segment ceramic heater according to any one of claims 1 to 3, wherein, The thickness of the jumper wire is 1.8 to 3.0 times the thickness of the outer section heater circuit.

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