Solid state relay power module and method of manufacture

Abstract

The application discloses a solid-state relay power component and a production method, which comprises a DCB substrate and power chips on the substrate. The power chips are composed of a first chip and a second chip, and the two power chips are inversely arranged on the substrate. Each power chip leads out a main electrode, and a conductive sheet is welded on the upper surface of each power chip. The conductive sheet of one power chip is connected with the corresponding electrode of the other power chip through a lead wire to realize the electrical connection between the power chips. The application adopts the chip flip mode, increases the conductive copper sheet, and welds the copper sheet on the anode of the chip. The copper sheet is electrically connected with the other chip through the binding aluminum wire, which effectively avoids the stress damage and thermal breakdown damage, and improves the service life of the solid-state relay.

Description

TECHNICAL FIELD

[0001] The application discloses a solid-state relay power assembly and a production method, and belongs to the technical field of solid-state relay manufacturing according to the international patent classification (IPC). BACKGROUND

[0002] A solid-state relay is a kind of electronic switch without contact breakage, and the input-output isolation device and the output power switch thereof are composed of electronic components. Compared with electromagnetic relays, the solid-state relay has the characteristics of reliable operation, long service life, small external interference and fast switching speed, and thus has a wide application field, and is the first choice of engineers, especially in occasions with large current and frequent switching.

[0003] At present, the power assembly of a large-power solid-state relay applied in the market is divided into two structures of a copper bridge welding type and a chip binding type. The two structures are prone to failure after being used for a period of time in the market application process.

[0004] The first power assembly structure is disclosed in the Chinese patent CN203481142U, and is formed by welding a "several" type copper bridge to form an electrical connection, as shown in the drawing, wherein the "several" type copper bridge a is welded on the surface of the chip electrode (such as position b) to form a shrinkage stress, so that the surface of the chip is pulled and damaged to cause failure, which belongs to stress breakdown failure. Figure 1 Figure 1

[0005] The second power assembly structure is to directly bind an aluminum wire on the surface of the chip electrode to form an electrical connection, as shown in the drawing, wherein the temperature of the binding aluminum wire (such as position c) rises sharply during the frequent switching of the relay, and after the temperature of the aluminum wire rises, a single-point heat concentration is formed at the binding point (such as position d) on the surface of the chip, which is prone to cause overheat breakdown of the single point on the surface of the chip to cause failure. Figure 2 Figure 2 Figure 2

[0006] The power assembly with the above two structures is prone to stress breakdown failure or heat breakdown failure, so that the solid-state relay has low reliability in many large-current application fields, and is not conducive to market promotion.

[0007] In the drawings, the gate electrode of the chip is led out through the bridge e, the bridge component is small, and in actual production, the bridge component is often manually attached, so that the production efficiency is low. Figure 1 Figure 2 SUMMARY

[0008] ​​​​​​​In view of the defects of the prior art, the solid-state relay power assembly effectively avoids stress damage and thermal breakdown damage, and improves the service life of the solid-state relay.

[0009] To achieve the above object, the application is implemented by the following technical scheme:

[0010] The solid-state relay power assembly structure comprises a substrate and a power chip thereon, the power chip is composed of a first chip and a second chip, the two power chips are inversely arranged on the substrate, each power chip leads out a main electrode, a conductive sheet is welded on the upper surface of each power chip, and the conductive sheet of one power chip is connected to the corresponding electrode of the other power chip through a lead wire to realize the electrical connection between the power chips.

[0011] Further, the conductive sheet is a copper sheet, the copper sheet is welded on the anode surface of the power chip, and the lead wire is bound on the surface of the copper sheet.

[0012] Further, the power chip is a thyristor chip, the cathode of the thyristor chip faces downward, the anode faces upward, and the thyristor chip is attached to the substrate to form an inverse combination structure.

[0013] Further, the gate control signal of the thyristor chip leads out a control electrode, and the control electrode and the main electrode are located on the same side of the power chip on the substrate.

[0014] Further, a bending part is arranged at the junction of the main electrode and the control electrode adjacent to the substrate to relieve the stress on the electrodes.

[0015] Further, the substrate is a DCB plate, and the lead wire is made of aluminum wire or silver wire or gold wire.

[0016] The application also provides a production method of the solid-state relay power assembly, comprising the following steps:

[0017] S1, patching

[0018] The DCB plate is smeared with tin paste, the first chip and the second chip are attached to the DCB plate by a patching machine, the cathode side of the two chips is attached to the DCB plate, the conductive sheet is attached to the anode surface of the two chips, and then the main electrode and the control electrode are assembled on the DCB plate.

[0019] S2, welding

[0020] The assembled DCB plate, the first chip, the second chip, the two main electrodes, the control electrode and the conductive sheet are welded by a welding platform.

[0021] S3, binding

[0022] After welding, the conductive sheet on the anode side of one chip is bound with a lead wire connected to the cathode of the other chip by a binding machine to form a power assembly.

[0023] In the step, the conductive sheet is a copper sheet, the lead wire is an aluminum wire, one end of the aluminum wire is bound to the upper surface of the copper sheet, and the other end of the aluminum wire is bound to the DCB plate connection point position led out by the cathode of the chip.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] 1. The power assembly of the present application adopts a flip chip mode, i.e. the cathode of the chip faces downward and the anode faces upward. The flip chip mode can simplify the design of the conductive sheet, i.e. the copper sheet, above the electrode and is easy to produce. The conductive sheet is not bent into a shape, effectively eliminating the bending stress of the conventional "several" type electric bridge, and improving the service life of the solid-state relay.

[0026] 2. The conductive sheet of the power chip binds the lead wire, balances the single-point heat, so that the single-point heat concentration does not occur on the electrode surface of the chip, and the overheat breakdown can be avoided, especially suitable for overcurrent impact protection, effectively improving the service life of the solid-state relay.

[0027] 3. When the chip is flipped, the cathode and the gate of the chip face downward, the gate signal is led out by the copper foil of the DCB plate, and the chip gate bridge (as shown in Figure 1 、 Figure 2 ) is omitted, improving the production efficiency.

[0028] 4. The control electrode and the main electrode of the chip are located on the same side of the chip, which can be conveniently welded. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a schematic diagram of a power assembly of a solid-state relay.

[0030] Figure 2 is a schematic diagram of another power assembly of a solid-state relay.

[0031] Figure 3 is a schematic diagram of an embodiment of the present application.

[0032] Figure 4 is another schematic diagram of an embodiment of the present application. DETAILED DESCRIPTION

[0033] The present application will be further described below in conjunction with the drawings:

[0034] Embodiment: Please refer to Figure 3 and Figure 4The application discloses a solid-state relay power assembly, which comprises a substrate 1 and power chips arranged on the substrate 1, wherein the power chips are composed of a first chip 21 and a second chip 22, the two power chips are arranged in a flip-chip mode on the substrate 1, each power chip has a main electrode 3, a conductive sheet 4 is welded on the upper surface of each power chip, the conductive sheet 4 of one power chip is connected with the corresponding electrode of the other power chip through a lead wire 5 to realize the electrical connection between the power chips, specifically, the conductive sheet 4 of the anode of the first chip 21 is connected with the copper foil of the cathode of the second chip 22 through the lead wire 5, and the copper foil is a preset copper material on the substrate, and the conductive sheet 4 of the anode of the second chip 22 is connected with the copper foil of the cathode of the first chip 21 through the lead wire 5. The conductive sheet 4 is a copper sheet or other conductive metal sheet, the copper sheet is welded on the anode surface of the power chip, and the lead wire 5 is bound on the surface of the copper sheet, the lead wire 5 is preferably an aluminum wire based on cost and performance, and other materials such as silver wire or gold wire can also realize the electrical connection. The power chip in the application is a thyristor chip, the thyristor chip has an anode, a cathode and a gate (control electrode), the cathode of the thyristor chip faces downward, the anode faces upward and is attached to the substrate to form a flip-chip assembly structure. The substrate 1 is a DCB board, which is a ceramic-based copper-clad plate, the gate control signal of the thyristor chip is led out to a control electrode 6, and the control electrode 6 and the main electrode 3 are located on the same side of the power chip on the substrate 1. The main electrode 3 and the control electrode 6 are provided with bending parts 31 and 61 at the joint parts adjacent to the substrate to relieve the stress of the electrodes. The power assembly in the application is a high-power solid-state relay assembly, and the electrodes are loose due to thermal expansion and contraction during use, thereby affecting the reliability of the relay. The bending parts provided at the electrodes adjacent to the welding points can effectively release the stress during use and improve the connection reliability of the electronic components.

[0035] The solid-state relay power assembly of the application is a copper sheet welding and aluminum wire binding type structure, which is different from the existing solid-state relay products. The power assembly adopts a chip flip-chip mode, and a square copper sheet is added, the copper sheet is welded on the anode of the chip, and the copper sheet is connected with another chip through binding aluminum wire above the copper sheet, thereby effectively avoiding the stress damage of the ''j'' type copper bridge and the thermal breakdown damage of the direct binding mode, and the service life of the solid-state relay is improved.

[0036] The application adopts a chip flip-chip mode, the cathode of the chip faces downward and the anode faces upward, the conventional chip assembly has the anode facing downward and the cathode facing upward, the flip-chip mode can simplify the design of the copper sheet above the electrode and is easy to produce, a square copper sheet with similar area is connected on the anode surface of the chip through welding, such as Figure 3As shown, the surface of the copper sheet is connected to the cathode of another chip by binding aluminum wire, so as to realize the electrical connection between the power chips. The welded square copper sheet effectively eliminates the bending stress of the conventional "J" type copper bridge because it is not bent into shape. The surface of the square copper sheet can balance the single-point heat by binding the aluminum wire, so that the single-point heat concentration does not occur on the surface of the chip electrode, and overheating breakdown can be avoided.

[0037] The application is mainly applied to a solid-state relay formed by assembling a solid-state relay power assembly and a control circuit shell, so that the solid-state relay cannot be damaged prematurely due to excessive mechanical stress or overheating breakdown in the application of frequent on-off of large current, and the service life of the product can be greatly improved.

[0038] The process flow of the solid-state relay power assembly is as follows

[0039] A solid-state relay power assembly production method comprises the following steps:

[0040] S1, patch

[0041] The DCB board is smeared with tin paste, and the first chip 21 and the second chip 22 are attached to the DCB board by a patch machine, wherein the cathode side of the two chips is attached to the DCB board, the anode surface of the two chips is attached to the conductive sheet 4, the conductive sheet 4 is a copper sheet, and then the two main electrodes 3 and the two control electrodes 6 are assembled on the DCB board to connect the corresponding electrodes of the chips;

[0042] S2, welding

[0043] The assembled DCB board, the first chip, the second chip, the two main electrodes, the control electrode and the conductive sheet are welded by a welding platform;

[0044] S3, binding

[0045] After welding, the surface of the conductive sheet 4 on the anode side of one chip is connected to the cathode of another chip by a binding machine to form a power assembly, the lead wire 5 is an aluminum wire, one end of the aluminum wire is bound to the upper surface of the copper sheet, and the other end of the aluminum wire is bound to the DCB board connection point of the chip cathode lead-out, and the binding machine is also called a lead wire bonding machine, which uses heat, pressure and ultrasonic energy to tightly weld the metal lead wire and the substrate pad.

[0046] In the application, the cathodes and gates of the first and second chips are directed towards the DCB board, the gate is led out by the copper foil preset on the DCB board, the control electrode and the main electrode are located on one side of the two chips, and the main electrode 3 and the control electrode 6 can be attached by the patch machine, thereby greatly improving the efficiency.

[0047] In the process of the solid-state relay power assembly of the application, the DCB board, chip and main electrode are pretreated before patching, such as cleaning the surface and drying, corresponding tooling is required when patching, and patching and welding are both performed according to corresponding process requirements, such as pressure, temperature and time, and the binding of the lead is sequentially completed according to the pre-set bonding strip number.

[0048] The application is not limited to the above-mentioned embodiments, and the same or similar structure design as the above-mentioned embodiments of the application or the substitution, modification, equivalent method and scheme made in the essence and range of the application are all within the protection scope of the application.

Claims

1. A solid state relay power module, characterized by: The application relates to a power chip and a substrate, the power chip is composed of a first chip and a second chip, the two power chips are inversely arranged on the substrate, each power chip leads out a main electrode, a conductive sheet is welded on the upper surface of each power chip, the conductive sheet of one power chip is connected with the corresponding electrode of the other power chip through a lead wire to realize the electrical connection between the power chips; the conductive sheet is a copper sheet, the copper sheet is welded on the anode surface of the power chip, and the lead wire is bound on the surface of the copper sheet; the power chip is a silicon controlled chip, the cathode of the silicon controlled chip faces downward, the anode faces upward and is attached to the substrate to form an inverse combination structure; the gate control signal of the silicon controlled chip leads out a control electrode, the control electrode and the main electrode are located on the same side of the power chip on the substrate; a bending part is arranged at the joint of the main electrode and the control electrode close to the substrate to relieve the stress on the electrodes.

2. A solid state relay power module according to claim 1, characterized in that: The substrate is a DCB plate, and the lead wire is made of aluminum, silver or gold.

3. A method of producing a solid state relay power module according to claim 1 or 2, characterized in that The application further discloses a manufacturing method of the power chip and the substrate, which comprises the following steps: S1, patching The DCB plate is smeared with tin paste, the first chip and the second chip are attached to the DCB plate through a patching machine, the cathode sides of the two chips are attached to the DCB plate, the conductive sheets are attached to the anode surfaces of the two chips, and then the main electrode and the control electrode are assembled on the DCB plate; S2, welding The assembled DCB plate, the first chip, the second chip, the two main electrodes, the control electrode and the conductive sheets are welded through a welding platform; S3, binding After the welding, the surface of the conductive sheet on the anode side of one chip is bound with the lead wire through a binding machine to be connected with the cathode of the other chip to form a power assembly.

4. A method of producing a solid state relay power assembly according to claim 3, characterized in that: The conductive sheet is a copper sheet, the lead wire is made of aluminum, silver or gold, one end of the lead wire is bound on the upper surface of the copper sheet, and the other end of the lead wire is bound on the DCB plate connecting point led out by the cathode of the chip.

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