Semiconductor switching device with pressure system

Abstract

To provide a semiconductor switching device and a method for assembling a semiconductor switching device.SOLUTION: A semiconductor switching device (1) comprises a gate ring (5) and a gate connector element (6) for contacting the gate ring (5), and comprises a pressure system (7) for pressing the gate connector element (6) onto the gate ring (5). The pressure system (7) comprises an insulating ring (11), and a plurality of spring beams (12) arranged circumferentially on the insulating ring (11). The insulating ring (11) comprises a plurality of supports (16, 17) for supporting ends of the spring beams (12).SELECTED DRAWING: Figure 6A

Description

[Technical Field]

[0001] The present disclosure relates to semiconductor switching devices and methods for fabricating semiconductor switching devices. The device may be a gate commutated thyristor (GCT), in particular an integrated gate commutated thyristor (IGCT). [Background technology]

[0002] Increasing the rating of the maximum controllable turn-off current required from the IGCT increases the size of the IGCT wafer from approximately 100 mm to 150 mm in diameter. This, in turn, increases the housing, leading to higher complexity and cost. Additionally, it must allow for easy installation of large-area devices. Furthermore, all components within the housing must already be properly aligned and supported during transport to ensure proper contact after shipping.

[0003] No. 9,698,067 discloses a spacer system for a semiconductor switching device formed as a spacer ring and a plurality of insulating elements.U.S. Patent No. 10,892,245 discloses a switching device comprising a semiconductor element and a housing with a spring system having a ring-shaped washer that laterally surrounds the semiconductor element to clamp the semiconductor element between two pole pieces. Summary of the Invention [Means for solving the problem]

[0004] SUMMARY OF THE INVENTION Embodiments of the present disclosure relate to improved semiconductor switching devices. According to a first aspect of the present disclosure, a semiconductor switching device includes a gate ring, a gate connector element for contacting the gate ring, and a pressure system for pressing the gate connector element onto the gate ring. The pressure system includes an insulating ring and a plurality of spring beams circumferentially arranged on the insulating ring, the insulating ring including a plurality of supports for supporting ends of the spring beams.

[0005] By way of example, the semiconductor switching device may be a gate commutated thyristor (GCT) or a gate turn-off thyristor (GTO). The semiconductor switching device may be an integrated gate commutated thyristor (IGCT).

[0006] Semiconductor switching devices are often shipped to customers as single components, and multiple devices may be stacked by the customer. In the stack, each device is clamped together. A pressure system presses the gate connector element onto the gate ring in the clamped state.

[0007] The gate connector element may include a plurality of fingers. Each of the fingers may be mounted on one of the spring beams. The fingers may be mounted on a central portion of the spring beam. The fingers may be partially bent around the spring beam.

[0008] Walls may be present between adjacent ones of the supports to prevent circumferential movement of the spring beam, thereby keeping the spring beam aligned with the fingers of the gate connector element.

[0009] The spring beams may include thickened portions in their central portions. Thus, the spring beams may be thicker in the central portions than at the ends. The thickened portions may protrude axially beyond the supports. This allows for a larger clearance between the gate ring and the supports. In addition, it allows for a clearance between the cathode pole piece and the semiconductor substrate during an unclamped state of the device.

[0010] The insulating ring may include a plurality of pins on a second side of the insulating ring opposite the first side on which the spring beam is disposed, the plurality of pins being configured to provide rotational locking of the insulating ring and / or further portions of the semiconductor switching device. As an example, rotational locking of a gate connector element may be achieved.

[0011] The switching device may include a spacer ring for insulating the gate connector element from the cathode pole piece. The pressure system may provide rotation locking for the spacer ring. The spacer ring may include a plurality of support elements for supporting the gate connector element and a plurality of slots between the support elements, with the pin engaging the slots. Thus, rotation locking can be achieved simply by inserting the pin into the slot.

[0012] Each of the support elements may include a first portion and a second portion. The gate connector element may be mounted on the first portion and prevented from rotating in one direction by the second portion. The first and second portions may be provided as a step.

[0013] The pressure system may be configured to be provided as a single component for assembly of the semiconductor switching device, such that the spring beam is firmly secured to the insulating ring by the support of the pressure system, allowing for quick and easy assembly and disassembly of the device.

[0014] According to a further aspect of the present disclosure, a method for assembling a semiconductor switching device includes providing a housing assembly for the semiconductor switching device and providing a pressure system for pressing a gate connector element onto a gate ring of the switching device. The housing assembly may include a housing, a gate connector element, and a cathode pole piece. The pressure system includes an insulating ring and a plurality of spring beams circumferentially disposed on the insulating ring, the insulating ring including a plurality of supports for supporting ends of the spring beams. In this method, the pressure system is assembled with the housing assembly, and the pressure system is provided as a single component.

[0015] A semiconductor switching device constructed in this manner may have any of the structural and functional characteristics of the devices described above.

[0016] Providing the pressure system in a single component form simplifies assembly, reducing costs and making it easier to ensure correct assembly compared to pressure systems where a single component is provided and the component is assembled separately from the equipment components.

[0017] A spacer ring may be provided to insulate the gate connector element from the cathode pole piece prior to assembly of the pressure system with the housing assembly, the spacer ring including a plurality of support elements, the spacer ring being positioned around the cathode pole piece and rotated until the gate connector element is positioned on the support elements of the spacer ring.

[0018] In particular, the fingers of the gate connector element may be disposed on a first support portion of the support element, with further rotation of the spacer ring being prevented by a second portion of the support element.

[0019] When assembling the pressure system, the pins of the pressure system may be inserted into the slots of the spacer ring, thereby achieving a simple and effective self-locking mechanism for the pressure system and the spacer ring.

[0020] After assembly of the pressure system, the fingers of the gate connector element may be bent so that they rest on the spring beams.

[0021] The present disclosure includes several aspects and embodiments, and any feature described with respect to one of the aspects and embodiments is also disclosed herein with respect to the other aspects and embodiments, even if the respective feature is not explicitly mentioned in this context.

[0022] Further features, improvements, and advantages will become apparent from the following description of exemplary embodiments taken in conjunction with the drawings, in which elements of the same structure and / or function may be referred to by the same reference numerals. It should be understood that the embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 10 is a cross-sectional view showing details of a switching device for one embodiment. [Figure 2A] FIG. 2 is a perspective view of a pressure system of the switching device of FIG. 1; [Figure 2B] FIG. 2B shows a detail of FIG. 2A. [Figure 2C] FIG. 2C shows a detail of FIG. 2B. [Figure 3] 2 shows the switching device of FIG. 1 in a clamped state; [Figure 4A] FIG. 4A is a perspective view of a spacer ring of a switching device according to one embodiment. [Figure 4B] FIG. 4B is an enlarged detail of FIG. 4A. [Figure 5A] 1A-1C are perspective views illustrating steps in a method for assembling a switching device according to one embodiment. [Figure 5B] 1A-1C are perspective views illustrating steps in a method for assembling a switching device according to one embodiment. [Figure 6A]FIG. 6A is a cross-sectional view of a detail of a switching device according to a further embodiment. [Figure 6B] FIG. 6B is a perspective view of the pressure system of the switching device of FIG. 6A. DETAILED DESCRIPTION OF THE INVENTION

[0024] 1 shows details of a semiconductor switching device 1. The switching device 1 may be a GCT (Gate-Commutated Thyristor), in particular an IGCT (Integrated Gate-Commutated Thyristor). The IGCT may be a large-area IGCT, with the gate structures on the GCT wafer being arranged around the periphery of the wafer.

[0025] The switching device 1 comprises a semiconductor substrate 2, a cathode pole piece 3, an anode pole piece 4, and a gate ring 5. The cathode pole piece 3 comprises a cathode strain buffer plate 19, and the anode pole piece 4 comprises an anode strain buffer plate 20. The strain buffer plates 19, 20 are made of a conductive material with a thermal expansion coefficient between the semiconductor substrate 2 and the respective pole pieces 3, 4. The gate ring 5 is electrically connected by a gate connector element 6.

[0026] The pressure system 7 serves to apply the necessary pressure to the gate connector element 6. The gate connector element 6 transfers the force applied to the gate ring 5 to ensure proper switching capability of the semiconductor substrate 2.

[0027] Additionally, the pressure system 7 functions to lock the element in place, for example, during shipping or vibration testing. The pressure system 7 locks the spacer ring 8, preventing it from rotating. The spacer ring 8 electrically insulates the gate connector element 6 from the cathode pole piece 3.

[0028] The switching device 1 comprises a housing 9 with an external creepage section, which is connected to the anode pole piece 4 by an anode flange 10.

[0029] During transportation and vibration testing, the switching device 1 is typically provided as a single component. During operation, a stack of clamped switching devices 1 can be formed to electrically interconnect the switching devices 1. In the stack, the anode pole piece 4 is pressed against the semiconductor substrate 2.

[0030] Figure 2A shows a pressure system 7 that may be part of the switching device 1 of Figure 1. Figure 2B shows an enlarged detail of Figure 2B, and Figure 2C shows an enlarged detail of Figure 2B.

[0031] The pressure system 7 comprises an insulating ring 11 of insulating material, which may for example comprise a plastic material.

[0032] The pressure system 7 further comprises a plurality of spring beams 12. The pressure system 7 may consist of an insulating ring 11 and a plurality of spring beams 12. The spring beams 12 are configured to deflect and then return to their original shape. The spring beams 12 may comprise a spring material such as spring steel. The pressure system 7 may be referred to as a "segmented" pressure system 7 with multiple spring beams 12 instead of a single spring extending circumferentially around the insulating ring 11.

[0033] The spring beams 12 are attached to a first side 13 of the insulating ring 11. The first side 13 may be referred to as the upper side. The spring beams 12 are arranged circumferentially along the first side 13 to form a closed ring. Each of the spring beams 12 is fixed at each of its ends 14, 15 to one of a plurality of supports 16, 17. The supports 16, 17 may be an integral part of the insulating ring 11. The spring beams 12 may be held within the supports 16, 17. The supports 16, 17 have a flexible, self-locking design so that the spring beams 12 are firmly fixed to the ring 2. As an example, the spring beams 12 may be clicked into the supports 16, 17.

[0034] The walls 18 between adjacent supports 16, 17 position the spring beam 12 in the correct circumferential position, thereby centering the spring beam 12 relative to the gate connector element 6 and ensuring accurate pressure distribution.

[0035] The segmented design of the insulating ring 11 allows for easy adjustment of the pressure on the gate ring 5 by changing the length, diameter, or total number of spring beams 12. Furthermore, the segmented design allows for a reduction in the overall height of the pressure system 7, which in turn allows for a reduction in the overall height of the housing 9 of the switching device 1. This allows for a reduction in overall height, especially in the case of low-voltage class designs.

[0036] The pressure system 7 includes a pin 21 on a second side 22 of the insulating ring 11. The second side 22 is opposite the first side 13 and may be a bottom side of the insulating ring 11. The pin 21 serves to hold further parts of the switching device 1 in place, as will be described in more detail in connection with Figures 5A and 5B. The pin 21 may be an integral part of the insulating ring 11.

[0037] Figure 3 shows the switching device 1 of Figure 1 in a clamped state. As distinguished from the unclamped state shown in Figure 1, the anode pole piece 4 is pressed towards the semiconductor substrate 2. The gap between the cathode strain buffer plate 19 and the semiconductor substrate 2 is eliminated.

[0038] In addition, the spring beams 12 are deflected downwards at their central portions and thus strained. The spring beams 12 therefore exert a spring force on the gate connector element 6 towards the gate ring 5. In the unclamped state shown in FIG. 1, the spring beams 12 are relaxed. It is also possible that the spring beams 12 are already slightly deflected and therefore strained in the unclamped state. It is also possible that the pressure system slightly presses the gate connector element onto the gate ring already in the unclamped state of the device.

[0039] 4A shows a perspective view of the spacer ring 8, and FIG. 4B shows a detail thereof. The spacer ring 8 comprises a ring-shaped wall 30 and a plurality of support elements 23 arranged circumferentially on the bottom side of the wall 30.

[0040] Each of the support elements 23 comprises a first portion 24 and a second portion 25, with the first portion 24 having a lower height than the second portion 25. The first portion 24 is provided to support the gate connector element 6, in particular the fingers 27 of the gate connector element 6 (see also FIG. 5A).

[0041] The second part 25 is configured to form a stop for the finger 27 when assembling the switching device 1 (see also FIG. 5A). The second part 25 may further form a support for the pressure system 7.

[0042] The slot 26 is configured to receive the pin 21 of the pressure system 7 (see FIG. 5B).

[0043] 5A and 5B show steps in a method for assembling the switching device 1. The switching device 1 and its components may be as described in connection with the previous figures.

[0044] 5A, a housing assembly 31 of the switching device 1 is provided, which includes a housing 9, a cathode pole piece 3, and a gate connector element 6. The gate connector element 6 is secured to the housing 9, for example by soldering between two portions of the housing 9. The housing assembly 31 also includes a further gate connector element 32 (see FIG. 3) secured to the housing 9 and secured to the cathode pole piece 3.

[0045] The spacer ring 8 is inserted into the housing assembly 31 from above. The slots 26 are initially aligned with the fingers 27 of the gate connector element 6. Once the spacer ring 8 is seated on the cathode pole piece 3, the spacer ring 8 is rotated until the fingers 27 seat on the first portion 24 of the support element 23. The rotation is stopped by the abutment of the fingers 27 on the left side of the second portion 25. The rotation is clockwise when looking at the housing 9 from top to bottom. Figure 5A shows the fingers 27 in an end position after rotation.

[0046] 5B shows a subsequent step in which the pressure system 7 is inserted into the housing 9 from above, so that the pins 21 fit into the slots 26. The pressure system 7 is inserted as a single pre-assembled part. The pressure system 7 may then seat on the second part 25 of the support element 23 and / or directly on the cathode pole piece 3.

[0047] In this position, the pressure system 7 prevents the fingers 27 from moving back counterclockwise. The spacer ring 8, pressure system 7 and fingers 27 are locked together and prevented from rotating. Thus, a self-locking design of the pressure system 7, gate connector element 6 and spacer ring 8 is provided.

[0048] Additionally, the spring beam 12 is also properly aligned with the fingers 27, with the pins 21 properly fitting into the slots 26. In the next step, the fingers 27 are bent onto the spring beam 12. The fingers 27 are aligned with the central portion of the beam 12 so that the pressure on the gate ring 5 can be evenly distributed.

[0049] Thereafter, the gate ring 5 , the semiconductor substrate 2 and the anode pole piece 4 are inserted into the housing 9 from above, and the anode flange 10 is fixed to the anode pole piece 4 .

[0050] Rotation locking by inserting pin 21 into slot 26 is simple and does not require special tools, so assembly is easier and faster than prior art where fingers 27 are bent into specific positions on the spacer ring to prevent the spacer ring from rotating.

[0051] 6A and 6B show a further embodiment of a semiconductor switching device 1 with a pressure system 7. The only distinguishing feature from the previous embodiment is that the spring beam 12 has a thickened portion 28 in its central portion. The thickened portion 28 may be an integral part of the rest of the spring beam 12. It is also possible that the thickened portion 28 is an additional element that surrounds the rest of the spring beam 12.

[0052] The thickened portion 28 causes the spring beam 12 to project axially beyond the supports 16,17. This allows for a larger clearance 29 between the cathode pole piece 3 and the semiconductor substrate 2. Furthermore, it ensures that the proper distance is maintained between the supports 16, 17 and the gate ring 5. The thickened portion 28 also allows for greater bending of the spring beam 12 without the gate ring 5 resting on the supports 16, 17.

[0053] Overall, the segmented pressure system 7 makes assembly of the switching device 1 easier, faster, and error-proof, as the pressure system 7 can be inserted into the housing 9 as pre-assembled components. This is an advantage over prior art techniques in which several disc springs and spring washers must be individually inserted into the housing 9 and each element must be precisely oriented during assembly of the GCT elements.

[0054] In addition, the segmented pressure system 7 can be made more compact in terms of overall height, which allows the housing 9 to also have a smaller height and lower costs, provided that it is sufficient for the desired voltage class.

[0055] Fine tuning of the spring characteristics of the pressure system 7 can be achieved by adjusting the number, diameter or length of the spring beams 12 to achieve the required pressure applied to the gate ring 5 .

[0056] The simple design of the spring beam 12, which is essentially a beam supported at both ends, allows for easy calculation of spring characteristics from the basic principles of mechanics in the first iteration. Suitable spring beams 12 are available on the market in a variety of material options and dimensions and are less expensive than the disc springs and spring washers of existing pressure systems. Due to the simplicity of the design, the pressure system 7 can be easily tested, for example, by 3D printing, before implementing the design in manufacturing. Furthermore, since the pressure system 7 includes only two stacked components, namely, the insulating ring 11 and the spring beam 12, the requirements for total thickness and clearance accuracy are lower than existing concepts that have more stacked components, namely, two washers and two disc springs. [Explanation of symbols]

[0057] Reference sign 1. Semiconductor switching device 2. Semiconductor substrate 3 cathode pole pieces 4 anode pole pieces 5 Gate Ring 6 Gate Connector Elements 7. Pressure System 8 Spacer ring 9. Housing 10 Anode flange 11 Insulation ring 12 Spring beam 13 First Side 14 End 15 End 16 Support 17 Support 18 Wall between supports 19 Cathode distortion buffer plate 20 Cathode distortion buffer plate 21-pin 22 Second Side 23 Supporting Elements 24 First Part 25 Second Part 26 slots 27 Finger 28 Thickened area 29 Clearance 30 Spacer Ring Wall 31 Housing Assembly 32 Further Gate Connector Elements

Claims

1. 1. A semiconductor switching device (1) comprising: a gate ring (5); a gate connector element (6) for contacting the gate ring (5); and a pressure system (7) for pressing the gate connector element (6) onto the gate ring (5), wherein the pressure system (7) comprises an insulating ring (11) and a plurality of spring beams (12) circumferentially arranged on the insulating ring (11), the insulating ring (11) comprising a plurality of supports (16, 17) for supporting ends (14, 15) of the spring beams (12).

2. 2. The semiconductor switching device (1) of claim 1, wherein the gate connector element (6) comprises a plurality of fingers (27), each of the fingers (27) resting on one of the spring beams (12).

3. 3. The semiconductor switching device (1) according to claim 1 or 2, further comprising a wall (18) between adjacent ones of the supports (16, 17) to prevent circumferential movement of the spring beam (12).

4. 3. The semiconductor switching device (1) according to claim 1 or 2, wherein the spring beam (12) comprises a thickened portion (28) in a central portion.

5. 3. The semiconductor switching device (1) according to claim 1 or 2, wherein the insulating ring (11) comprises a plurality of pins (21) on a second side (22) of the insulating ring (11) opposite to a first side (13) on which the spring beam (12) is arranged, the plurality of pins (21) being configured to provide a rotational lock of the pressure system (7) and / or further parts of the semiconductor switching device (1).

6. 6. The semiconductor switching device (1) according to claim 5, further comprising a spacer ring (8) for insulating the gate connector element (6) from the cathode pole piece (3), the pressure system (7) providing a rotation lock for the spacer ring (8).

7. 7. The semiconductor switching device (1) according to claim 6, wherein the spacer ring (8) comprises a plurality of support elements (23) for supporting the gate connector element (6) and a plurality of slots (26) between the support elements (23), and the pin (21) engages with the slots (26).

8. 8. The semiconductor switching device (1) according to claim 7, wherein each of the support elements (23) comprises a first portion (24) and a second portion (25), and the gate connector element (6) is mounted on the first portion (24) and is prevented from rotating in one rotational direction by the second portion (25).

9. 3. The semiconductor switching device (1) according to claim 1 or 2, wherein the pressure system (7) is configured to be provided as a single component for assembly of the semiconductor switching device (1).

10. 3. The semiconductor switching device (1) according to claim 1 or 2, wherein the semiconductor switching device (1) is selected from a gate commutated thyristor, an integrated gate commutated thyristor and a gate turn-off thyristor.

11. A method for fabricating a semiconductor switching device (1) comprising a gate ring (5), comprising the steps of: A) A housing (9), a gate connector element (6), and a cathode pole piece (3). a housing assembly (31) for the semiconductor switching device (1) including the gate connector element (6) and a pressure system (7) for pressing the gate connector element (6) onto the gate ring (5), the pressure system (7) comprising an insulating ring (11) and a plurality of spring beams (12) circumferentially arranged on the insulating ring (11), the insulating ring (11) comprising a plurality of supports (16, 17) for supporting ends (14, 15) of the spring beams (12); B) Assembling the pressure system (7) with the housing assembly (31) The pressure system (7) is provided as a single part, and A method comprising:

12. Before B), the gate connector element (6) is insulated from the cathode pole piece (3).

12. The method of claim 11, wherein a spacer ring (8) is provided for the cathode pole piece (3), the spacer ring (8) comprising a plurality of support elements (23), the spacer ring (8) is placed around the cathode pole piece (3) and rotated until the gate connector element (6) is placed on the support elements (23) of the spacer ring (8).

13. 13. The method of claim 12, wherein the gate connector element (6) comprises a plurality of fingers (27), the support element (23) comprises a first portion (24) and a second portion (25), and the spacer ring (8) is rotated until the fingers (27) are disposed on the first portion (24), and further rotation is prevented by the second portion (25).

14. 14. The method of claim 13, wherein assembling the pressure system (7) comprises inserting pins (21) of the pressure system (7) into slots (26) of the spacer ring (8).

15. The method according to any one of claims 11 to 14, wherein the gate connector element (6) comprises a plurality of fingers (27), the fingers (27) being bent to be disposed on the spring beam (12).

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