A high speed four channel digital isolator ceramic package housing

Abstract

The utility model discloses a high -speed four -channel digital isolator package shell, including ceramic shell and electrode, the ceramic shell body includes ceramic base and seal ring, and the seal ring is brazed with ceramic base through solder, guarantees the air -tightness of packaging, the first recess is made in the ceramic base, two second recesses are still designed in the first recess, and the inner electrode is made in the first recess, second recess, and the inner electrode is connected with the outer electrode of ceramic shell bottom through the conductive column and metal interlayer, the outer electrode has 16, and all leads from the side, the inner electrode on the first recess is the wire bonding area, and the chip sintering is flush with the first recess, and the wire bonding of chip and inner electrode is convenient. The second recess is as the chip sintering area, and the recess increases the longitudinal insulation distance of parts, and the control of chip sintering alignment and solder is convenient. The utility model has the characteristics of good insulation performance, high -speed low loss, high voltage resistance, small volume, good air -tightness, strong corrosion resistance, high reliability etc.

Description

Technical Field

[0001] This utility model relates to microelectronic device packaging, specifically a ceramic package shell for a high-speed four-channel digital isolator. Background Technology

[0002] With the rapid development of industrial automation and aerospace, the demand for high-performance, high-reliability signal isolation technology is increasing. Digital isolators, as key components, need to achieve efficient and stable signal transmission in extreme environments, especially under high voltage conditions. The isolation voltage performance directly determines the safety and reliability of the device. Existing plastic packaging suffers from insufficient reliability under high temperature, high humidity, and strong vibration environments, while traditional ceramic packaging still has room for optimization in structural design and material selection. Simultaneously, it is necessary to achieve domestic substitution for foreign products to achieve independent control.

[0003] To solve the above problems, the inventors have provided the following technical solution through research and numerous experiments. Utility Model Content

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

[0005] The technical solution of this utility model is:

[0006] A high-speed four-channel digital isolator packaging structure includes a ceramic housing and electrodes. The ceramic housing comprises a ceramic base and a sealing ring. The sealing ring is connected to the ceramic base by soldering to ensure the hermeticity of the package. A first groove is formed within the ceramic base, and two second grooves are designed within the first groove. Internal electrodes are formed in both the first and second grooves. The internal electrodes are connected to external electrodes at the bottom of the ceramic housing via conductive posts and a metal interlayer. There are 16 external electrodes, all led out from the side. Specifically, the connection method between the internal and external electrodes is as follows: the first internal electrode is connected to the first external electrode; the second internal electrode is connected to the second external electrode and the eighth external electrode; the third internal electrode is connected to the third external electrode... The electrodes are connected as follows: 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 and fifteenth outer electrodes; 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 the second groove is the chip sintering area. After the chip is sintered, it is flush with the first groove, which facilitates the wire bonding between the chip and the inner electrode.

[0007] Preferably, the 16 external electrodes at the bottom of the ceramic package have a lead-out height of 0.5 mm from the side.

[0008] Preferably, the height of the second groove is 0.3 mm.

[0009] Preferably, the lateral spacing between the two second grooves is 0.8 mm, and metallized blank spaces are retained on both sides of the partition wall.

[0010] Preferably, the ceramic encapsulation shell has dimensions of 6mm × 10.2mm × 2.75mm.

[0011] The principle of this invention is as follows: The 16 external electrodes at the bottom of the ceramic package are all led out from the side with a lead-out height of 0.5mm. This design helps to distribute the electric field evenly, avoids electric field concentration that could lead to local breakdown, enhances the overall withstand voltage, and also helps to weld the parts, increasing the welding strength and surface mount yield. In addition, the leads on the external electrodes have a certain thickness, which helps to improve the signal transmission efficiency, makes them easier to solder during installation and fixation, and increases the welding strength. The inner electrode on the first groove serves as the wire bonding area, its size primarily reserved for the wire bonding region. Signal transmission mainly occurs through the ceramic interior, where the excellent insulation of the ceramic material provides good electromagnetic shielding, reducing surface current leakage. Placing signal transmission within the ceramic reduces interference between adjacent signal lines and improves signal transmission integrity. Two second grooves are also machined within the first groove, serving as chip sintering areas. The second grooves are 0.3mm high. This groove design increases the longitudinal insulation distance between components, helping to improve the breakdown voltage between isolator chips and enhance electrical isolation performance. It also facilitates chip sintering alignment and solder control. Furthermore, after sintering, the chip is flush with the first groove, facilitating wire bonding between the chip and the inner electrode. The lateral spacing between the two second grooves is 0.8mm, and metallization blanks 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 isolator's withstand voltage performance, and prevents high-voltage breakdown.

[0012] The materials selected are as follows: the ceramic base B1 is made of alumina ceramic to enhance the thermal performance of the parts; the outer electrodes 1 to 16 are made of 4J42 alloy; the sealing ring B2 is also made of 4J42 alloy. The sealing ring is annular and is connected to the ceramic base B1 by brazing with solder to ensure the airtightness of the encapsulation; the conductive pillars inside the base are made of tungsten paste, and the metal interlayer material is molybdenum-copper alloy. One end of the conductive pillar is flush with the inner surface of the groove. A layer of tungsten is printed on its surface, then a layer of nickel is electroplated, and finally a layer of gold is electroplated to form the inner electrode.

[0013] The beneficial effects of this utility model are:

[0014] This ceramic package utilizes the excellent insulation and high strength properties of cermet materials and adopts an alumina ceramic structure design. Based on the operating characteristics of electronic devices, the internal casing is designed with a chip sintering area and bonding area with good isolation and safety distance, meeting the product's reliability requirements: ① meeting the requirements for high-speed signal transmission; ② meeting the requirements for high isolation voltage; ③ meeting the requirements for assembling various types of chips; ④ meeting the insulation requirements of the bottom of the casing.

[0015] This utility model utilizes a ceramic package to encapsulate a high-speed four-channel digital isolator. By optimizing the signal transmission path, it meets the requirements of high-speed signal transmission. Two grooves are designed within the ceramic package, and metallized blanks are created on both sides of the isolation wall, improving the chip's isolation voltage performance. The bottom pins of the ceramic package extend from the side, which helps to distribute the electric field evenly, avoiding localized breakdown caused by electric field concentration, enhancing the overall withstand voltage capability, and increasing soldering strength and surface mount yield. This ceramic package features excellent insulation performance, high speed and low loss, high voltage resistance, small size, good hermeticity, strong corrosion resistance, and high reliability. Attached Figure Description

[0016] Figure 1 This is a diagram of the internal structure of the ceramic shell of this utility model;

[0017] Figure 2 This is a diagram showing the pin distribution at the bottom of the ceramic housing of this utility model;

[0018] Figure 3 This is a side cross-sectional view of the ceramic shell of this utility model;

[0019] Figure 4 This is a side view of the ceramic housing pins of this utility model;

[0020] Figure 5 This is a functional block diagram of four channels with the same input direction in this utility model;

[0021] Figure 6 This is a functional block diagram of the present invention, which has three positive input channels and one negative input channel.

[0022] Figure 7 This is a functional block diagram of the present invention, showing two positive input channels and two negative input channels.

[0023] In the diagram: 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 external electrode. 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 Implementation

[0024] The technical solution of this utility model is further described below, but the scope of protection is not limited to what is described.

[0025] A ceramic package housing for a high-speed four-channel digital isolator includes a ceramic housing and electrodes. The ceramic housing 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 hermeticity of the package. A first groove L1 is formed within the ceramic base B1. Two second grooves L2 are designed within the first groove L1. Internal electrodes are formed in both the first groove L1 and the second groove L2. The internal electrodes are connected to external electrodes via conductive posts and a metal interlayer. Specifically, the first internal electrode A1 is connected to the first external electrode 1, the second internal electrode A2 is connected to the second external electrode 2 and the eighth external electrode 8, the third internal electrode A3 is connected to the third external electrode 3, the fourth internal electrode A4 is connected to the fourth external electrode 4, the fifth internal electrode A5 is connected to the fifth external electrode 5, and the sixth internal electrode A5 is connected to the fifth external electrode 5. 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 increases the longitudinal insulation distance of the parts and facilitates chip sintering alignment and solder control. In addition, after sintering, the chip is flush with the first groove L1, which facilitates wire bonding between the chip and the internal electrodes.

[0026] This utility model is designed as a dual-chip integration. The chip is sintered within the second groove L2, and the ceramic package shell can be adapted to different chip models through a sintering process, thereby supporting different electrical connections and pin definitions. 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 ground pins 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 (the specific connection depends on the model of the sintered chip), the sixth external electrode 6 is the input channel IND or the output channel OUTD (the specific connection depends on the model of the sintered chip), the seventh external electrode 7 is the reverse output enable EN1 or no connection (the specific connection depends on the model of the sintered chip), the ninth external electrode 9 and the fifteenth external electrode 15 are ground pins GND2, the tenth external electrode 10 is the positive output enable EN2, the eleventh external electrode 11 is the output channel OUTD or the input channel IND (the specific connection depends on the model of the sintered chip), the twelfth external electrode 12 is the output channel OUTC or the input channel INC (the specific connection depends on 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 ceramic package housing for a high-speed four-channel digital isolator, comprising a ceramic housing and electrodes, characterized in that: The ceramic shell includes a ceramic base and a sealing ring. The sealing ring is brazed to the ceramic base to ensure the airtightness of the seal. A first groove is formed inside the ceramic base, and two second grooves are designed within the first groove. Internal electrodes are formed in both the first and second grooves. These internal electrodes are connected to external electrodes at the bottom of the ceramic shell via conductive posts and a metal interlayer. There are 16 external electrodes, all extending from the side. The connection method between the internal and external electrodes is as follows: the first internal electrode is connected to the first external electrode; the second internal electrode is connected to the second and eighth external electrodes; the third internal electrode is connected to the third external electrode; and the fourth internal electrode is connected to the fourth external 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 and fifteenth outer electrodes, 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 serves as the chip sintering area. After the chip is sintered, it is flush with the first groove to facilitate wire bonding between the chip and the inner electrode.

2. The ceramic package housing for the high-speed four-channel digital isolator according to claim 1, characterized in that, The 16 external electrodes at the bottom of the ceramic package have a lead-out height of 0.5 mm from the side.

3. The ceramic package housing for the high-speed four-channel digital isolator according to claim 1, characterized in that, The height of the second groove is 0.3mm.

4. The ceramic package housing for the high-speed four-channel digital isolator according to claim 1, characterized in that, The lateral spacing between the two second grooves is 0.8mm, and the metallized blank space is retained on both sides of the partition wall.

5. The ceramic package housing for the high-speed four-channel digital isolator according to claim 1, characterized in that, The ceramic encapsulation shell measures 6mm × 10.2mm × 2.75mm.

6. The ceramic package housing for the high-speed four-channel digital isolator according to claim 1, characterized in that, One end of the conductive post is metallized and connected to the surface of the groove, and the conductive post body is connected to the internal metal interlayer. The other end of the conductive post is connected to the outer electrode of the ceramic base, realizing the electrical connection between the inner and outer electrodes. The pins on the outer electrode are 0.1mm thicker than the ceramic base B1, which makes them easier to weld and increases the welding strength during installation and fixing.

7. The ceramic package housing for the high-speed four-channel digital isolator according to claim 1, characterized in that, The metallization of the inner electrode on the groove surface is achieved by printing a layer of tungsten metal on its surface, then electroplating a layer of nickel, and finally electroplating a layer of gold.

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