High voltage application circuit

Abstract

To provide a high voltage application circuit capable of suppressing a corona discharge.SOLUTION: A high voltage application circuit of the present disclosure comprises: a first metal material having a flat surface connected to a ground potential; a first insulation material with a flat plate shape, provided onto the flat surface of the first metal material; a second sheet-like metal material that is provided onto the flat surface on the side opposite to the first metal material of the first insulation material; a circuit board onto which a component to which a first high voltage having an absolute value of 10kV or more is applied is mounted; and a second insulation material covering an edge part of the second metal material. Of the component, a first component high potential portion having a potential similar to a first high voltage and a first circuit board high potential portion whose potential of a conductive region of the circuit board is similar to the first high voltage are electrically connected to the second metal material. The second metal material includes a region containing all of the first component high potential portion and the first circuit board high potential portion in a plan view, and a corner part of the edge part of the second metal material is formed in a curved shape.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a high voltage application circuit. [Background technology]

[0002] Plasma processing apparatuses used in the process of manufacturing semiconductor wafers or liquid crystal substrates are provided with a power supply device that generates a high voltage, such as a pulse power supply device that generates a pulsed voltage (pulse voltage) (see, for example, Patent Document 1).

[0003] A pulse power supply is configured, for example, to convert DC power into AC power using an inverter circuit, then convert the converted AC power into AC power of a different voltage value using a transformer, rectify and smooth the converted AC power, and generate a pulse voltage using a switching circuit or the like. In such a pulse power supply, a high voltage with an absolute value of approximately 10 kV is applied to a switching element, such as a MOSFET, used in the high-voltage application circuit. Components such as the switching element are mounted on a circuit board. As is well known, the higher the applied voltage, the more likely corona discharge occurs.

[0004] For example, Patent Document 2 discloses a technique for suppressing corona discharge. Patent Document 2 discloses a technique for preventing the occurrence of corona discharge caused by the concentration of an electric field in a gap (part of a screw hole) around a screw (at ground potential) in a high-voltage application circuit that includes components such as a switching element. Specifically, a conductor at ground potential is inserted between the gap around the screw and the high-potential part, thereby eliminating the concentration of an electric field in the gap and suppressing corona discharge. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-125729 [Patent Document 2] Japanese Patent Application Publication No. 2018-067644 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned Patent Document 2 only addresses the gaps around the screws. Furthermore, the applied voltage is approximately 3.3 kV, which is relatively low compared to approximately 10 kV. When a high voltage of 10 kV or more in absolute value is applied, corona discharges are more likely to occur. Therefore, measures must be taken to prevent corona discharges from occurring between high-potential parts of components to which a high voltage of 10 kV or more in absolute value is applied, or high-potential parts of circuit boards (such as board patterns) that have the same potential as the high-potential parts, and components at ground potential. Corona discharges are particularly likely to occur from component terminals and angular parts, so measures to suppress corona discharges in these areas are necessary.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a high-voltage application circuit that can suppress corona discharge between a high-potential portion of a component to which a high voltage of 10 kV or more in absolute value is applied, or a high-potential portion of a circuit board having the same potential as the high-potential portion, and a component at ground potential. [Means for solving the problem]

[0008] The high-voltage application circuit according to the present disclosure includes a first metal material having a plane connected to ground potential, a flat first insulating material provided on the plane of the first metal material, a sheet-like second metal material provided on the plane of the first insulating material opposite the first metal material, a circuit board mounted with components to which a first high voltage having an absolute value of 10 kV or more is applied, and a second insulating material covering an edge of the second metal material. A first component high-potential region of the component, which has the same potential as the first high voltage, and a first circuit board high-potential region of a conductive region of the circuit board, which has the same potential as the first high voltage, are electrically connected to the second metal material. The second metal material has an area that includes both the first component high-potential region and the first circuit board high-potential region in a plan view, and the edge of the second metal material has curved corners. [Effects of the Invention]

[0009] According to the present disclosure, in a high-voltage application circuit, corona discharge can be suppressed between a first component high-potential portion of a component to which a first high voltage having an absolute value of 10 kV or more is applied or a first circuit board high-potential portion of a circuit board having the same potential as the first component high-potential portion, and a component at ground potential. Note that the effects described herein are not necessarily limited to those described herein, and may be any of the effects described in this specification. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view of a high voltage application circuit according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the high voltage application circuit as viewed from the right side of FIG. [Figure 3] FIG. 3 is a plan view of the high voltage application circuit of FIG. 1 as seen from above. [Figure 4] FIG. 4 is a plan view of a comparative example corresponding to FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of a high voltage application circuit according to the present disclosure will be described in detail with reference to the accompanying drawings 1 to 4. FIG.

[0012] Fig. 1 is a cross-sectional view of the high-voltage application circuit 1 of this embodiment, and Fig. 2 is a cross-sectional view of the high-voltage application circuit 1 as viewed from the right side of Fig. 1. Fig. 3 is a plan view of the high-voltage application circuit 1 of Fig. 1 as viewed from above, and Fig. 4 is a plan view of a comparative example corresponding to Fig. 3.

[0013] 1 and 2, the high-voltage application circuit 1 includes a water-cooled copper plate 11, a ceramic 12 provided on the upper side of the water-cooled copper plate 11 (the upper side of FIGS. 1 and 2), a copper plating 13 provided on the upper side of the ceramic 12, a circuit board 14 provided on the upper side of the copper plating 13, and a mold 15 that covers the edge of the copper plating 13. The mold 15 is made of an insulating material such as silicone.

[0014] The water-cooled copper plate 11 is an example of a "first metal material" and has a flat surface connected to ground potential. More specifically, the water-cooled copper plate 11 is configured so that cooling water can circulate inside the flat copper plate. This enhances the cooling effect. The flat copper plate is also connected to ground potential.

[0015] The ceramic 12 is an example of a "first insulating material" and is a flat plate-shaped member provided on the plane of the water-cooled copper plate 11 (first metal material). Preferably, alumina is used, and the thickness in this embodiment is 10 mm. Generally, the thicker the ceramic 12, the longer the distance between the copper plating 13 (described below) and the water-cooled copper plate 11, which works to make it more difficult for corona discharge to occur. However, the thicker the ceramic 12, the less effective the heat dissipation effect of the water-cooled copper plate 11 becomes, so it is not preferable to make it too thick. By using alumina ceramics for the ceramic 12 and setting the thickness to 10 mm as in this embodiment, it is possible to obtain a sufficient heat dissipation effect while suppressing corona discharge when a first high voltage with an absolute value of 10 kV or more is applied to the component.

[0016] The copper plating 13 is an example of a "second metal material" and is a sheet-like member provided on the plane of the ceramic 12 (first insulating material) opposite to the water-cooled copper plate 11 (first metal material). The second metal material is not limited to the copper plating 13, and for example, a copper tape can also be used.

[0017] A MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) 16 is mounted on the circuit board 14. The MOSFET 16 is an example of a "component" to which a first high voltage having an absolute value of 10 kV or more is applied. As shown in FIGS. 1 and 2, the MOSFET 14 is disposed so as to be in contact with the copper plating 13. That is, in the example of FIGS. 1 and 2, the MOSFET 16 is mounted on the lower side of the circuit board 14 (the side facing the copper plating 13 in FIGS. 1 and 2). However, the present invention is not limited to this, and the mounting form of the MOSFET 16 (component) on the circuit board 14 is arbitrary. For example, the MOSFET 16 may be mounted on the upper side of the circuit board 14 (the side not facing the copper plating 13 in FIGS. 1 and 2). Note that examples of the "component" are not limited to the MOSFET 16, and may be, for example, a diode, an inductor, or the like.

[0018] MOSFET 16 of this embodiment has first component high potential portion 17, the potential of which is the same as a first high voltage (e.g., 12 kV), and second component high potential portion 18, to which a second high voltage (e.g., 13.5 kV) different from the first high voltage is applied. In this embodiment, first component high potential portion 17 is a portion of the terminal of MOSFET 16 that has the same potential as the first high voltage, and second component high potential portion 18 is a portion of the terminal of MOSFET 16 that has the same potential as the second high voltage.

[0019] For ease of explanation, the examples in FIGS. 1 and 2 show only two terminals of MOSFET 16 that are at a high potential. Here, the terminal including first component high potential portion 17 is referred to as the "first terminal," and the terminal including second component high potential portion 18 is referred to as the "second terminal." In the examples in FIGS. 1 and 2, the first terminal is connected to electronic component 101 (including a board pattern) arranged on the surface of circuit board 14 opposite to MOSFET 16, and the second terminal is connected to electronic component 102 (including a board pattern) arranged on the surface of circuit board 14 opposite to MOSFET 16. Note that the number and types of electronic components mounted on circuit board 14 are arbitrary and are not limited to electronic components 101 and 102.

[0020] Furthermore, the circuit board 14 has, within its conductive region, a first circuit board high potential portion 19 whose potential is the same as the first high voltage, and a second circuit board high potential portion 20 whose potential is the same as the second high voltage. In this embodiment, the first circuit board high potential portion 19 is electrically connected to the first component high potential portion 17, and the second circuit board high potential portion 20 is electrically connected to the second component high potential portion 18. In this embodiment, the terminals (first terminal, second terminal) of the MOSFET 16 and the conductive region of the circuit board 14 are joined by soldering or the like.

[0021] Furthermore, the first circuit board high potential portion 19 is connected to the copper plating 13 via a spacer 21, which is a conductive material. In other words, the first component high potential portion 17 and the first circuit board high potential portion 19 are electrically connected to the copper plating 13 (second metal material). The conductive material for connecting the first circuit board high potential portion 19 and the copper plating 13 is not limited to the spacer 21 and is arbitrary. For example, the first circuit board high potential portion 19 and the copper plating 13 may be connected via a cable. On the other hand, the second circuit board high potential portion 20 and the copper plating 13 are not electrically connected.

[0022] Furthermore, on the surface of the circuit board 14 facing the copper plating 13 (the lower surface of the circuit board 14 in Figures 1 and 2), the area near the edge outside the circuit board high potential portion 19 and the second circuit board high potential portion 20 is connected to the ceramic 12 via a spacer 22 which is an insulating material.

[0023] In this embodiment, the copper plating 13 has an area that includes both the first component high potential portion 17 and the first circuit board high potential portion 19 in plan view. As shown in FIG. 3, the edges of the copper plating 13 have curved corners. Note that FIG. 3 does not show the MOSFET 16 (component), circuit board 14, and spacers 21 and 22. Furthermore, because a mold 15 is provided to cover the edges of the copper plating 13, the edges of the copper plating 13 are hidden and cannot be seen in plan view such as FIG. 3. Therefore, the edges of the copper plating 13 are indicated by dashed lines in FIG. 3.

[0024] When a first high voltage with an absolute value of 10 kV or more is applied to the MOSFET 16 (component), not only the first component high potential portion 17 of the MOSFET 16 (a portion having the same potential as the first high voltage) but also the conductive area of ​​the circuit board 14 connected to the first component high potential portion 17 becomes a high potential portion (first circuit board high potential portion 19). Because the water-cooled copper plate 11 is at ground potential, the potential difference between the first component high potential portion 17 or the first circuit board high potential portion 19 and the water-cooled copper plate 11 becomes 10 kV or more, which may result in corona discharge. In particular, corona discharge is more likely to occur at the terminals and angular portions of components because charge tends to concentrate there than at rounded portions. Therefore, corona discharge is more likely to occur at the tips and bent portions of the terminals of the MOSFET 16 (areas surrounded by dotted lines in Figures 1 and 2).

[0025] However, as described above, in this embodiment, the copper plating 13 has an area that includes all of the first component high potential portion 17 and the first circuit board high potential portion 19 in a plan view. Therefore, the copper plating 13 is present between the first component high potential portion 17 or the first circuit board high potential portion 19, which may generate corona discharge and include terminals and angular portions of components where corona discharge is likely to occur, and the water-cooled copper plate 11, which is at ground potential. Here, the first component high potential portion 17, the first circuit board high potential portion 19, and the copper plating 13 are at the same potential, so corona discharge does not occur between them.

[0026] Therefore, if a corona discharge were to occur between the first component high potential portion 17 or the first circuit board high potential portion 19 and the water-cooled copper plate 11, it would be a corona discharge that does not pass through the copper plating 13. However, the possibility of corona discharge occurring along such a path is low because realizing a corona discharge that does not pass through the copper plating 13 would require a non-linear discharge path.

[0027] Note that corona discharge may occur between the copper plating 13 and the water-cooled copper plate 11, which is at ground potential. For example, as shown in FIG. 4, if the copper plating 13 has a shape with corners, such as a square, corona discharge may occur at those locations. This is because, as described above, charge is more likely to concentrate and corona discharge occurs at terminals and angular locations of components than at rounded locations. FIG. 4 is a plan view showing a comparative example of this embodiment, in which the mold 15 in FIG. 3 is omitted and the copper plating 13 is square with four corners.

[0028] In contrast, in this embodiment, as shown in FIG. 3, the corners (edges) of the copper plating 13 (second metal material) are formed into a curved shape, thereby suppressing the occurrence of corona discharge. Furthermore, as described above, in this embodiment, a mold 15 (second insulating material) is further provided to cover the edges of the copper plating 13. This is because the mold 15 has a higher dielectric strength than air. By providing this mold 15, the occurrence of corona discharge from the copper plating 13 can be further suppressed. As a result, even under conditions where corona discharge occurred at -11.5 kV in a conventional high-voltage application circuit, no corona discharge occurred even at -13.5 kV when configured as described above.

[0029] Therefore, if the high voltage application circuit 1 is configured as in the above embodiment, corona discharge between the first component high potential portion 17 or the first circuit board high potential portion 19 and the water-cooled copper plate 11 can be suppressed.

[0030] In addition, in this embodiment, the second component high potential area 18 and the second circuit board high potential area 20 have an area narrower than the copper plating 13 in a planar view, and the absolute value of the potential difference between the second high voltage and the first high voltage is smaller than the absolute value of the potential difference between the first high voltage and ground potential, and is the absolute value of the potential difference at which no corona discharge occurs between the second component high potential area 18 or the second circuit board high potential area 20 and the copper plating 13.

[0031] As described above, the second component high potential portion 18 and the second circuit board high potential portion 20 have an area narrower than the copper plating 13 (second metal material) in plan view. Therefore, the copper plating 13 is present between the second component high potential portion 18 or the second circuit board high potential portion 20 and the water-cooled copper plate 11 (first metal material) at ground potential. Therefore, the copper plating 13 has the effect of suppressing corona discharge even in the second component high potential portion 18 or the second circuit board high potential portion 20.

[0032] Of course, the second high voltage (e.g., 13.5 kV) is different from the first high voltage (e.g., 12 kV). Therefore, the degree of suppression of corona discharge is thought to be lower than the suppression effect in the relationship between first component high potential portion 17 or first circuit board high potential portion 19 and copper plating 13 by the potential difference between the two (e.g., 1.5 kV). However, even with the above configuration, there is still an effect of suppressing corona discharge.

[0033] Although the above description has been given taking the example where the second high voltage is higher than the first high voltage, the corona discharge suppression effect is similarly achieved even when the second high voltage is lower than the first high voltage.

[0034] As described above, in this embodiment, the MOSFET 16 (component) is disposed so as to be in contact with the copper plating 13 (second metal material), and the first metal material disposed on the opposite side of the ceramic 12 (first insulating material) from the copper plating 13 is the water-cooled copper plate 11. Components such as MOSFETs tend to reach high temperatures and therefore require heat dissipation. Therefore, by disposing the MOSFET 16 so as to be in contact with the copper plating 13, the MOSFET 16 can be thermally connected to the water-cooled copper plate 11 via the copper plating and the ceramic 12. This allows the heat of the MOSFET 16 to be dissipated from the water-cooled copper plate 11.

[0035] Moreover, the heat dissipation effect can be further improved by using the water-cooled copper plate 11 as the first metal material. That is, the above configuration not only suppresses corona discharge but also improves the heat dissipation effect of the MOSFET 16 (component).

[0036] In addition, applying an oil compound between the MOSFET 16 (component) and the copper plating 13 (second metal material) increases the degree of adhesion between the MOSFET 16 and the copper plating 13, which is more preferable in terms of heat dissipation. Also, applying an oil compound between the ceramic 12 (first insulating material) and the water-cooled copper plate 11 (first metal material) increases the degree of adhesion between the ceramic 12 (first insulating material) and the water-cooled copper plate 11 (first metal material), which is more preferable in terms of heat dissipation.

[0037] Furthermore, as described above, in this embodiment, the sheet-like second metal material provided on the opposite side of the ceramic 12 (first insulating material) from the water-cooled copper plate 11 (first metal material) can be made substantially uniform in thickness by being made of copper plating 13. This makes it easier to increase the degree of adhesion between the second metal material and the component (MOSFET 16) provided on the second metal material (the side of the second metal material opposite the ceramic 12). Therefore, making the sheet-like second metal material of copper plating 13 makes it easier to improve the heat dissipation effect.

[0038] Although the embodiments of the present disclosure have been described above, the above-described embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These novel embodiments and modifications thereof are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims.

[0039] Furthermore, the effects of the embodiments described in this specification are merely examples and are not limiting, and other effects may also be obtained. [Explanation of symbols]

[0040] 1 High voltage application circuit 11 Water-cooled copper plate 12. Ceramic 13 Copper plating 14 Circuit Board 15 Mold 16 MOSFET 17 First component high potential area 18 Second component high potential area 19 1st circuit board high potential area 20 2nd circuit board high potential area 21 Spacer 22 spacer

Claims

1. a first metal material having a plane connected to a ground potential; a first insulating material having a flat plate shape provided on a plane of the first metal material; a sheet-like second metal material provided on a plane of the first insulating material opposite to the first metal material; a circuit board on which components are mounted to which a first high voltage having an absolute value of 10 kV or more is applied; a second insulating material covering an edge of the second metal material; a first component high potential portion of the component, the potential of which is the same as the first high voltage, and a first circuit board high potential portion of the conductive region of the circuit board, the potential of which is the same as the first high voltage, are electrically connected to the second metal material; the second metal material has a region that includes both the first component high potential portion and the first circuit board high potential portion in a plan view, The edge portion of the second metal material has a corner formed into a curved shape. High voltage application circuit.

2. the component has a second component high potential portion to which the second high voltage different from the first high voltage is applied, the conductive region of the circuit board includes a second circuit board high potential portion having the same potential as the second high voltage; the second component high potential portion and the second circuit board high potential portion have an area narrower than the second metal material in a plan view, the absolute value of the potential difference between the second high voltage and the first high voltage is smaller than the absolute value of the potential difference between the first high voltage and the ground potential, and is the absolute value of the potential difference at which no corona discharge occurs between the second component high potential portion or the second circuit board high potential portion and the second metal material; The high voltage application circuit according to claim 1 .

3. The component is disposed in contact with a second metal material, The first metal material is a water-cooled copper plate.

3. The high voltage application circuit according to claim 1 or 2.

4. The sheet-like second metal material is formed by copper plating.

4. The high voltage application circuit according to claim 1.

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