High-speed four-channel digital isolator ceramic packaging shell

Abstract

The invention discloses a high-speed four-channel digital isolator packaging shell which comprises a ceramic shell body and electrodes, the ceramic shell body comprises a ceramic base and a sealing ring, the sealing ring is brazed with the ceramic base through welding flux, and the air tightness of packaging is guaranteed; a first groove is manufactured in the ceramic base, two second grooves are further designed in the first groove, inner electrodes are manufactured in the first groove and the second grooves, the inner electrodes are connected with outer electrodes at the bottom of the ceramic shell through conductive columns and metal interlayers, and the 16 outer electrodes are all led out from the side face. The inner electrode on the first groove is a lead bonding area, and the chip is flush with the first groove after being sintered, so that lead bonding of the chip and the inner electrode is facilitated. The second groove serves as a chip sintering area, the longitudinal insulation distance of the part is increased through the grooves, and chip sintering alignment and control over welding flux are facilitated. The invention has the characteristics of good insulating property, high speed, low loss, high voltage resistance, small volume, good air tightness, strong corrosion resistance, high reliability and the like.

Description

Technical Field

[0001] The invention relates to microelectronic device packaging, in particular to a high-speed four-channel digital isolator ceramic packaging shell. Background Art

[0002] With the rapid development of industrial automation and aerospace, the demand for high-performance, high-reliability signal isolation technology is growing. As key components, digital isolators must provide efficient and stable signal transmission in extreme environments, especially high voltage. Isolation voltage performance directly determines the safety and reliability of the device. Existing plastic packaging suffers from reliability issues in high temperature, high humidity, and high vibration environments. Traditional ceramic packaging still has room for improvement in structural design and material selection. At the same time, domestic substitution of foreign products is needed to achieve independent control.

[0003] To solve the above problems, the inventors have provided the following technical solutions through research and multiple experiments. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: through packaging structure design and optimized material selection, a ceramic packaging shell with high isolation voltage performance, high speed, low loss and high reliability is designed, which is suitable for the assembly of high-speed four-channel capacitor isolators. At the same time, the product miniaturization is achieved and it can replace the SOP16W package of similar products in situ.

[0005] The technical solution of the present invention is: a packaging shell of a high-speed four-channel digital isolator, including a ceramic shell and electrodes, characterized in that: the ceramic shell includes a ceramic base and a sealing ring, the sealing ring is connected to the ceramic base by soldering to ensure the airtightness of the package; a first groove is made in the ceramic base, and two second grooves are designed in the first groove, and inner electrodes are made in the first groove and the second groove, and the inner electrode is connected to the outer electrode at the bottom of the ceramic shell through a conductive column and a metal interlayer. There are 16 outer electrodes, all of which are led out from the side. The connection method of the inner and outer electrodes is specifically: the first inner electrode is connected to the first outer electrode, the second inner electrode is connected to the second outer electrode and the eighth outer electrode, the third inner electrode is connected to the third outer electrode, the fourth inner electrode is connected to the fourth outer electrode, the fifth inner electrode is connected to the fifth outer electrode, and the fourth inner electrode is connected to the fourth outer electrode. The sixth inner electrode is connected to the sixth outer electrode, the seventh inner electrode is connected to the seventh outer electrode, the eighth inner electrode is connected to the tenth outer electrode, the ninth inner electrode is connected to the eleventh outer electrode, the tenth inner electrode is connected to the twelfth outer electrode, the eleventh inner electrode is connected to the thirteenth outer electrode, the twelfth inner electrode is connected to the fourteenth outer electrode, the thirteenth inner electrode is connected to the ninth outer electrode and the fifteenth outer electrode, and the fourteenth inner electrode is connected to the sixteenth outer electrode; the inner electrode on the first groove is the wire bonding area, and its size mainly reserves the wire bonding area. After the chip is sintered, it is flush with the first groove, which is convenient for wire bonding between the chip and the inner electrode; the second groove is used as the chip sintering area. The groove design can increase the longitudinal insulation distance of the parts, and at the same time facilitates the chip sintering alignment and solder control. After sintering, the chip is flush with the first groove, which is convenient for wire bonding between the chip and the inner electrode. Preferably, the lead-out height of the 16 external electrodes at the bottom of the ceramic package shell from the side is 0.5 mm.

[0006] Preferably, the second groove has a height of 0.3 mm.

[0007] Preferably, the lateral spacing between the two second grooves is 0.8 mm, and metallized blank space is retained on both sides of the isolation wall. This design optimizes the electric field distribution around the chip, reduces electric field concentration, improves the voltage resistance of the isolator, and prevents the occurrence of high-voltage breakdown.

[0008] Preferably, the size of the ceramic package shell is 6 mm×10.2 mm×2.75 mm.

[0009] Preferably, the ceramic base B1 is made of alumina ceramics to enhance the thermal performance of the part; the outer electrode is made of 4J42 alloy; the sealing ring is also made of 4J42 alloy; the conductive column inside the base is metal tungsten slurry, and the metal interlayer material is molybdenum-copper alloy.

[0010] One end of the conductive column is connected to the metallized surface of the groove, the conductive column is connected to the internal metal interlayer, and the other end of the conductive column is connected to the external electrode of the ceramic base to achieve electrical connection between the internal and external electrodes. The pins on the external electrode have a certain thickness of 0.1μm compared to the ceramic base B1, which makes it easier to weld during installation and can increase the welding strength. The metallization of the inner electrode on the groove surface is formed by printing a layer of metal tungsten on its surface, then electroplating a layer of nickel, and finally electroplating a layer of gold.

[0011] The pins on the external electrodes of the present invention have a certain thickness, which helps to improve the signal transmission efficiency and solderability. The 16 external electrodes at the bottom of the ceramic package shell are all led out from the side, with a lead-out height of 0.5mm. This design helps to evenly distribute the electric field, avoid local breakdown caused by electric field concentration, enhance the overall pressure resistance, and at the same time help weld parts, increase welding strength and patch quality rate; the inner electrode on the first groove is the lead bonding area, and its size mainly reserves the lead bonding area. The signal is mainly transmitted from the inside of the ceramic. The excellent insulation of the ceramic material itself has good electromagnetic shielding force, reduces surface leakage, and places the signal transmission inside the ceramic to reduce the distance between adjacent signal lines. Interference between the two chips can be reduced, thereby improving the integrity of signal transmission; two second grooves are also processed in the first groove as the chip sintering area. The height of the second groove is 0.3mm. The groove design can increase the longitudinal insulation distance of the parts, which helps to improve the breakdown voltage between the isolator chips and enhance the electrical isolation performance. At the same time, it is convenient for the chip sintering alignment and solder control. In addition, the chip is flush with the first groove after sintering, which is convenient for the lead bonding of the chip to the inner electrode. The lateral spacing between the two second grooves is 0.8mm, and metallized blanks are retained on both sides of the isolation wall. This design optimizes the electric field distribution around the chip, reduces the electric field concentration phenomenon, improves the voltage resistance of the isolator, and prevents the occurrence of high-voltage breakdown.

[0012] Beneficial effects of the present invention: This ceramic package shell utilizes the excellent insulation and high strength properties of the metal ceramic material itself, adopts an alumina ceramic structure design, and designs a chip sintering area and bonding area with good isolation and safety distance inside the shell according to the working nature of the electronic device, meeting the reliability requirements of the product: 1. Meeting the needs of high-speed signal transmission; 2. Meeting the needs of high isolation voltage use; 3. Meeting the needs of assembling a variety of different types of chips; 4. Meeting the insulation requirements of the bottom of the shell.

[0013] The ceramic package shell has the characteristics of good insulation performance, high speed and low loss, high voltage resistance, small size, good airtightness, strong corrosion resistance and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a diagram showing the internal structure of the ceramic housing of the present invention; Figure 2This is a pin distribution diagram of the bottom of the ceramic housing of the present invention; Figure 3 is a side sectional view of the ceramic housing of the present invention; Figure 4 This is a side pin diagram of the ceramic housing of the present invention; Figure 5 This is a functional block diagram of four channels with the same input direction in the present invention; Figure 6 This is a functional block diagram of the present invention with three forward input channels and one reverse input channel; Figure 7 This is a functional block diagram of the present invention with two forward channels and two reverse channels as input.

[0015] In the figure: 1-first external electrode; 2-second external electrode; 3-third external electrode; 4-fourth external electrode; 5-fifth external electrode; 6-sixth external electrode; 7-seventh external electrode; 8-eighth external electrode; 9-ninth external electrode; 10-tenth external electrode; 11-eleventh external electrode; 12-twelfth external electrode; 13-thirteenth external electrode; 14-fourteenth external electrode; 15-fifteenth external electrode; 16-sixteenth external electrode; A1-first internal electrode; A2-second Inner electrode; A3-third inner electrode; A4-fourth inner electrode; A5-fifth inner electrode; A6-sixth inner electrode; A7-seventh inner electrode; A8-eighth inner electrode; A9-ninth inner electrode; A10-tenth inner electrode; A11-eleventh inner electrode; A12-twelfth inner electrode; A13-thirteenth inner electrode; A14-fourteenth inner electrode; B1-ceramic base; B2-sealing ring; B3-pin; L1-first groove; L2-second groove. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0017] A high-speed four-channel digital isolator ceramic package shell, including a ceramic shell and electrodes. The ceramic shell includes a ceramic base B1 and a sealing ring B2. The sealing ring B2 is connected to the ceramic base B1 by soldering to ensure the airtightness of the package. A first groove L1 is made in the ceramic base B1, and two second grooves L2 are designed in the first groove L1. Inner electrodes are made in the first groove L1 and the second groove L2. The inner electrodes are connected to the outer electrodes through conductive columns and metal interlayers. Specifically, the first inner electrode A1 is connected to the first outer electrode 1, the second inner electrode A2 is connected to the second outer electrode 2 and the eighth outer electrode 8, the third inner electrode A3 is connected to the third outer electrode 3, the fourth inner electrode A4 is connected to the fourth outer electrode 4, the fifth inner electrode A5 is connected to the fifth outer electrode 5, and the sixth inner electrode A6 is connected to the sixth outer electrode 6. Electrode A6 is connected to the sixth external electrode 6, the seventh internal electrode A7 is connected to the seventh external electrode 7, the eighth internal electrode A8 is connected to the tenth external electrode 10, the ninth internal electrode A9 is connected to the eleventh external electrode 11, the tenth internal electrode A10 is connected to the twelfth external electrode 12, the eleventh internal electrode A11 is connected to the thirteenth external electrode 13, the twelfth internal electrode A12 is connected to the fourteenth external electrode 14, the thirteenth internal electrode A13 is connected to the ninth external electrode 9 and the fifteenth external electrode 15, and the fourteenth internal electrode A14 is connected to the sixteenth external electrode 16. The second groove serves as the chip sintering area. The groove design can increase the longitudinal insulation distance of the parts, while facilitating chip sintering alignment and solder control. In addition, after sintering, the chip is flush with the first groove L1, facilitating wire bonding between the chip and the internal electrodes.

[0018] The present invention is designed as a dual-chip integration, the chip is sintered in the second groove L2, and the ceramic package shell can adapt to different types of chips through the sintering process, thereby supporting different electrical connections and pin definitions. The specific implementation is as follows Figure 2As shown, the first external electrode 1 is the power supply VCC1, the second external electrode 2 and the eighth external electrode 8 are the ground pin GND1, the third external electrode 3 is the input channel INA, the fourth external electrode 4 is the input channel INB, the fifth external electrode 5 is the input channel INC or the output channel OUTC, and the specific connection situation is determined by the model of the sintered chip, the sixth external electrode 6 is the input channel IND or the output channel OUTD, and the specific connection situation is determined by the model of the sintered chip, the seventh external electrode 7 is the reverse output enable EN1 or no connection, and the specific connection situation is determined by the model of the sintered chip, the ninth external electrode 9 and the fifteenth external electrode 15 are the ground pin GND2, the tenth external electrode 10 is the forward output enable EN2, the eleventh external electrode 11 is the output channel OUTD or the input channel IND, and the specific connection situation is determined by the model of the sintered chip, the twelfth external electrode 12 is the output channel OUTC or the input channel INC, and the specific connection situation is determined by the model of the sintered chip, the thirteenth external electrode 13 is the output channel OUTB, the fourteenth external electrode 14 is the output channel OUTA, and the sixteenth external electrode 16 is the power supply VCC2.

Claims

1. A high-speed four-channel digital isolator package housing, comprising a ceramic housing and electrodes, characterized in that: The ceramic shell includes a ceramic base and a sealing ring, which is connected to the ceramic base by brazing through solder to ensure the airtightness of the package; a first groove is made in the ceramic base, and two second grooves are designed in the first groove, and inner electrodes are made in the first groove and the second groove. The inner electrode is connected to the outer electrode at the bottom of the ceramic shell through a conductive column and a metal interlayer. There are 16 outer electrodes, all of which are led out from the side. The connection method of the inner and outer electrodes is as follows: the first inner electrode is connected to the first outer electrode, the second inner electrode is connected to the second outer electrode and the eighth outer electrode, the third inner electrode is connected to the third outer electrode, and the fourth inner electrode is connected to the fourth outer electrode. The fifth inner electrode is connected to the fifth outer electrode, the sixth inner electrode is connected to the sixth outer electrode, the seventh inner electrode is connected to the seventh outer electrode, the eighth inner electrode is connected to the tenth outer electrode, the ninth inner electrode is connected to the eleventh outer electrode, the tenth inner electrode is connected to the twelfth outer electrode, the eleventh inner electrode is connected to the thirteenth outer electrode, the twelfth inner electrode is connected to the fourteenth outer electrode, the thirteenth inner electrode is connected to the ninth outer electrode and the fifteenth outer electrode, and the fourteenth inner electrode is connected to the sixteenth outer electrode; the inner electrode on the first groove is the wire bonding area; the second groove is used as the chip sintering area, and the chip is flush with the first groove after sintering, which is convenient for wire bonding between the chip and the inner electrode.

2. The high-speed four-channel digital isolator package according to claim 1, characterized in that: The lead height of 16 external electrodes at the bottom of the ceramic package shell extending from the side is 0.5 mm.

3. The high-speed four-channel digital isolator package according to claim 1, wherein: The height of the second groove is 0.3 mm.

4. The high-speed four-channel digital isolator package according to claim 1, wherein: The lateral spacing between the two second grooves is 0.8mm, and metallized blank spaces are retained on both sides of the isolation wall. This design optimizes the electric field distribution around the chip, reduces electric field concentration, improves the voltage resistance of the isolator, and prevents the occurrence of high-voltage breakdown.

5. The high-speed four-channel digital isolator package according to claim 1, wherein: The ceramic package case measures 6mm×10.2mm×2.75mm.

6. The high-speed four-channel digital isolator package according to claim 1, characterized in that: The ceramic base B1 is made of alumina ceramic to enhance the thermal performance of the part; the outer electrode is made of 4J42 alloy; the sealing ring is also made of 4J42 alloy; the conductive column inside the base is metal tungsten slurry, and the metal interlayer material is molybdenum-copper alloy.

7. The high-speed four-channel digital isolator package according to claim 1, wherein: One end of the conductive column is connected to the metallized surface of the groove, the conductive column is connected to the internal metal interlayer, and the other end of the conductive column is connected to the external electrode of the ceramic base to achieve electrical connection between the internal and external electrodes. The pins on the external electrode have a certain thickness of 0.1mm compared to the ceramic base B1, which makes it easier to weld during installation and fixation and can increase the welding strength.

8. The high-speed four-channel digital isolator package according to claim 1, wherein: The metallization of the inner electrode of the groove surface is formed by printing a layer of metal tungsten on the surface, then electroplating a layer of nickel, and finally electroplating a layer of gold.

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