Packaging structure of D-type controller chip integrated with gallium nitride device
Through the formal + flip-flip hybrid packaging structure, the gallium nitride device and the Class D audio controller are combined, solving the problems of complexity of circuit design and inaccurate protection functions of multi-chip discrete solutions, and achieving high power density and simplified user experience.
Patent Information
- Application Number
- CN202521207744.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-13
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2035-06-13
AI Technical Summary
The existing gallium nitride device processes are difficult to make analog and digital circuits, and are difficult to compatible with silicon-based processes, resulting in multi-chip discrete solutions that increase the difficulty of circuit design, high cost, and difficult to accurately implement protection functions, and low power density, making it impossible to exert the advantages of high power density of gallium nitride.
The formal + flip-flip hybrid packaging structure is adopted to seal the gallium nitride device and the Class D audio controller in one packaging structure, interconnection is achieved through flip-fitting copper column connection and bonding wire, bonding is used to bond thermally conductive silver glue, and plastic packaging material is injected to form a flat footless type package.
It simplifies user circuit design, improves system integration, realizes precise protection functions, reduces parasitic resistance and inductance, and fully utilizes the advantages of low on-resistance and high power density of gallium nitride devices.
Smart Images
Figure CN223156020U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of integrated circuit packaging, and particularly to a packaging structure of a Class D controller chip integrating gallium nitride devices. Background Art
[0002] Compared with silicon-based power MOSFETs, gallium nitride HEMT devices have the advantages of high voltage resistance, low on-resistance (Rdson), and small parasitic capacitance. For medium and high-power Class D audio power amplifiers, using gallium nitride HEMT devices as the switching devices of the output stage has significant advantages in terms of power density, efficiency, etc. compared with traditional MOSFET-based devices.
[0003] However, the existing gallium nitride device processes are difficult to fabricate analog and digital circuits and are also difficult to be compatible with the existing silicon-based processes, resulting in audio power amplifiers using gallium nitride HEMT devices as switching semiconductor devices being all multi-chip discrete solutions, that is, the Class D controller, gate driver, and switching semiconductor device (GaN HEMT) are all independent chips, and circuits need to be built on a PCB board.
[0004] This multi-chip discrete solution increases the difficulty of user circuit design, has a high cost, and it is difficult to accurately implement protection functions. For example, overcurrent protection is greatly affected by external interference and temperature; the power density of the overall solution is low, the PCB area is large, and the advantages of high power density of gallium nitride cannot be exerted. Summary of the Utility Model
[0005] Based on this, it is necessary to provide a packaging structure of a Class D controller chip integrating gallium nitride devices for the above technical problems.
[0006] A packaging structure of a Class D controller chip integrating gallium nitride devices, the packaging structure includes: a Class D audio controller and multiple gallium nitride devices;
[0007] The gallium nitride devices are flip-chip mounted on one side of the upper surface of the bottom frame; the lower surface of the bottom frame is the pin of the finally packaged chip.
[0008] The Class D audio controller is face-up mounted on the other side of the upper surface of the bottom frame, connected to the corresponding pins on the frame by bonding wires, and interconnected with the gallium nitride devices, where a part of the interconnection is an exposed pin and the other part is an internal interconnection.
[0009] The bottom frame is placed in a mold, and the lower surface of the bottom frame is in parallel contact with the bottom inside the mold, and a molding compound is injected into the mold.
[0010] In one embodiment, the class-D audio controller is a conventional silicon process chip. The pads of the class-D audio controller are used for wire bonding with the package pins and for internal connection with the gallium nitride device.
[0011] In one embodiment, there are multiple copper pillar structures on the surface of the gallium nitride device. The bumps at the top of the copper pillars are solder. The gallium nitride device is inverted and the bumps are soldered onto the upper surface of the bottom frame.
[0012] In one embodiment, the encapsulation material covers the bottom frame. The encapsulation material has the same size and shape as the bottom frame, and the final product is a flat leadless type package.
[0013] In one embodiment, the class-D audio controller is attached to the other side of the upper surface of the bottom frame by thermal conductive silver glue.
[0014] In one embodiment, the packaging structure further includes several temperature-sensitive elements; one temperature-sensitive element is arranged on the substrate of each of the class-D audio controller and the gallium nitride device.
[0015] The above-mentioned packaging structure of the class-D controller chip integrated with gallium nitride devices includes: a class-D audio controller and multiple gallium nitride devices; the gallium nitride devices are flip-chip mounted on one side of the upper surface of the bottom frame; the lower surface of the bottom frame is the pin of the finally packaged chip; the class-D audio controller is face-up mounted on the other side of the upper surface of the bottom frame and is wire-bonded to the corresponding pins on the frame; the bottom frame is placed in a mold, and the lower surface of the bottom frame is in parallel contact with the bottom inside the mold, and the encapsulation material is injected into the mold. This packaging structure adopts a hybrid packaging of face-up + flip-chip, encapsulating the gallium nitride devices and the class-D audio controller in one packaging structure, which is convenient for users, improves the system integration degree, and can accurately implement various protection functions. Description of the Drawings
[0016] Figure 1 It is a schematic longitudinal sectional structure diagram of the packaging of the class-D controller chip integrated with gallium nitride devices in one embodiment;
[0017] Figure 2 It is a schematic structure diagram of the packaging of the class-D controller chip integrated with gallium nitride devices in one embodiment;
[0018] Figure 3 It is a top view of the frame design of the packaging of the class-D controller chip integrated with gallium nitride devices in another embodiment. Detailed Embodiments
[0019] To make the objectives, technical solutions and advantages of this application more clear and understandable, the following further describes this application in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.
[0020] In one embodiment, as Figure 1 shown, a packaging structure of a class-D controller chip integrated with gallium nitride devices is provided. The packaging structure includes: a class-D audio controller 10 and multiple gallium nitride devices 20;
[0021] The gallium nitride devices 20 are flip-chip mounted on one side of the upper surface of the bottom frame; the lower surface of the bottom frame is the pin of the finally packaged chip.
[0022] Specifically, gallium nitride devices usually have an extremely low on-resistance. Traditional fully integrated (referring to integrated power MOSFET) high-power audio power amplifiers all use wire bonding packaging, and the wire bonding from the chip to the frame is copper wire. The on-resistance of the gallium nitride devices used in audio power amplifiers is often only a few milliohms. If wire bonding is used, even if multiple wire bondings are in parallel, the resistance introduced by the wire bonding is already close to the on-resistance of gallium nitride, resulting in a waste of the performance of gallium nitride devices. Parasitic inductance poses a challenge to the drain-source voltage detection of the chip. To fully utilize the low on-resistance ability of gallium nitride devices, the flip-chip packaging method is selected for gallium nitride devices, using short and thick copper pillars (typical parameters: 100um long, 60mil in diameter) to replace wire bonding (typical parameters: >1000um long, 2mil in diameter). Both the parasitic resistance (10 milliohms vs <1 milliohm) and the parasitic inductance (nH vs pH level) are greatly reduced.
[0023] According to the electrical connection relationship in the co-packaged chip, a bottom frame with a specific shape is designed. The lower surface of this bottom frame is the pin of the finally packaged chip. This specially designed shape is for fan-out of the gallium nitride devices, that is, connecting to the pins of the chip. The pin distribution of the chip is determined by the functions of the chip and the corresponding circuits.
[0024] The gallium nitride devices 20 and the class-D audio controller 10 are arranged in a planar manner. The main reason is that both the class-D audio controller 10 and the gallium nitride devices 20 need to be led out to the pins of the packaged chip, and it is not easy to perform fan-out when stacked.
[0025] The class D audio controller 10 is mounted on the other side of the upper surface of the bottom frame, connected to the corresponding pins on the frame and the interconnection with the gallium nitride device by bonding wires, part of which is exposed pins and the other part is internal interconnection. In the actual package, some bonding wires are connected to the class D audio controller and the frame of the gallium nitride device (for example, the connection between the G pole of the gallium nitride device and the class D audio controller chip). The specific gallium nitride device has three groups of pins G / D / S, of which S / D has both bonding wire interconnection with the controller chip (connected from the pad of the controller chip to the frame pin where the gallium nitride chip is inverted, and the final chip appearance is invisible), and is directly inverted on the frame (copper pillar interconnection), becoming the pin seen on the final chip appearance; G is only connected to the controller.
[0026] Specifically, the Class D audio controller is mounted in a positive manner and attached to the frame with heat-conducting silver glue. It is connected to the corresponding pins on the frame with bonding wires. The Class D audio controller is a conventional silicon process chip. After the wafer factory is processed, there are pads left for bonding wires to connect to the package pins. The packaging structure of the Class D controller chip with integrated gallium nitride devices is as follows: Figure 2 As shown, Figure 2 The small circles G / D / S in the middle are the copper pillar connections of the flip-chip GaN device. , The numbers of the package pins "3.2400, 3.4400" are the area sizes where the Class D audio controller can be attached, and the red grid line area is the silver-plated area.
[0027] like Figure 1 As shown, the Class-D audio controller on the left is forward mounted on the frame and connected to the chip pins and other locations inside the package with bonding wires.
[0028] The bottom frame is placed in the mold, the lower surface of the bottom frame is in parallel contact with the bottom of the inside of the mold, and the plastic packaging material is injected into the mold.
[0029] The shape of the frame injected under the frame is not the final shape. After the plastic sealing material is injected, it will go through the etching and grinding processes to reach the final shape. After the metal etching is completed, the plastic sealing material is ground flat.
[0030] The power capability proposed in this application is in the range of 100W~500W, and the framework design of the packaging method of the ClassD controller and the gallium nitride device is a hybrid packaging method of top-down + flip-down.
[0031] The packaging structure of the Class-D controller chip integrated with a gallium nitride device can accurately implement various protection functions. The main reasons are as follows: First, an integrated package is adopted, where the gallium nitride transistor is closer to the controller chip, the leads are shorter, and the parasitic parameters, especially the parasitic inductance, are much smaller compared to external gallium nitride (discrete chip solutions). Second, a flip-chip structure is adopted, with short and thick copper pillars connected to the chip pin frame, which has smaller resistance and parasitic inductance compared to wire bonding connections.
[0032] In the packaging structure of the above Class-D controller chip integrated with a gallium nitride device, the packaging structure includes: a gallium nitride device and a Class-D audio controller; the gallium nitride device is flip-chip mounted on one side of the upper surface of the bottom frame; the lower surface of the bottom frame is the pin of the finally packaged chip; the Class-D audio controller is surface-mounted on the other side of the upper surface of the bottom frame and is connected to the corresponding pins on the frame by wire bonding; the bottom frame is placed in a mold, and the lower surface of the bottom frame is in parallel contact with the bottom inside the mold, and a plastic encapsulation material is injected into the mold. This packaging structure adopts a hybrid packaging of surface mount + flip-chip, encapsulating the gallium nitride device and the Class-D audio controller in one packaging structure, which is convenient for users, improves the system integration, and can accurately implement various protection functions.
[0033] In one embodiment, the Class-D audio controller 10 is a conventional silicon process chip. The pads of the Class-D audio controller 10 are used for wire bonding connections to the packaging pins and for internal connections to the gallium nitride device.
[0034] In one embodiment, there are multiple copper pillar structures on the surface of the gallium nitride device 20. The bumps at the top of the copper pillars are solder. The gallium nitride device 20 is turned upside down and the bumps are soldered to the upper surface of the bottom frame.
[0035] Specifically, as Figure 1 shown, on the right side of the bottom frame, the gallium nitride chip first undergoes a bump processing technology to fabricate multiple copper pillar structures on the surface, and the bumps at the top of the copper pillars are solder. When packaging the co-encapsulated chip, the gallium nitride chip is turned upside down and the bumps are soldered to the upper surface of the bottom frame.
[0036] The plastic encapsulation material is filled in the part between the gallium nitride surface and the frame, that is, the copper pillars are wrapped by the plastic encapsulation material.
[0037] In one embodiment, the plastic encapsulation material covers the bottom frame, and the plastic encapsulation material has the same size and shape as the bottom frame. The final product is a flat leadless type package.
[0038] Specifically, the packaging structure of the Class-D controller chip integrated with the gallium nitride device is a flat leadless type (QFN) package, and the plastic encapsulation body and the frame are equal in the plan view. As a preference, the thickness of a single plastic encapsulation body is 0.9 mm.
[0039] In one embodiment, the Class-D audio controller 10 is attached to the other side of the upper surface of the bottom frame by a thermally conductive silver adhesive.
[0040] In one embodiment, as Figure 3 shown, the packaging structure further includes a plurality of temperature-sensitive elements; one temperature-sensitive element is arranged on the substrate of the Class-D audio controller and each gallium nitride device.
[0041] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.
[0042] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.
Claims
1. A packaging structure of a class D controller chip integrated with a gallium nitride device, characterized in that, The encapsulation structure includes: a class-D audio controller and multiple gallium nitride devices; The gallium nitride devices are flip-chip mounted on one side of the upper surface of the bottom frame; the lower surface of the bottom frame is the pin of the finally encapsulated chip; The class-D audio controller is face-up mounted on the other side of the upper surface of the bottom frame, connected to the corresponding pins on the frame by bonding wires, and interconnected with the gallium nitride devices, where a part of the interconnection is an exposed pin and another part of the interconnection is an internal interconnection; The bottom frame is placed in a mold, and the lower surface of the bottom frame is in parallel contact with the bottom inside the mold, and a plastic encapsulation material is injected into the mold.
2. The packaging structure of the class D controller chip for an integrated gallium nitride device according to claim 1, characterized in that, The class-D audio controller is a conventional silicon process chip, and the pads of the class-D audio controller are used for bonding wire connection with the package pins and internal connection with the gallium nitride devices.
3. The packaging structure of the class-D controller chip for an integrated gallium nitride device according to claim 1, wherein There are multiple copper pillar structures on the surface of the gallium nitride device, and the bumps at the top of the copper pillars are solder. The gallium nitride device is inverted and the bumps are soldered on the upper surface of the bottom frame.
4. The packaging structure of the class-D controller chip for an integrated gallium nitride device according to claim 1, characterized in that, The plastic encapsulation material covers the bottom frame, and the plastic encapsulation material has the same size and shape as the bottom frame. The final finished product is a flat leadless type package.
5. The package structure of the class D controller chip for an integrated gallium nitride device according to claim 1, characterized in that The class-D audio controller is attached to the other side of the upper surface of the bottom frame by thermal conductive silver paste.
6. The packaging structure of the class D controller chip for an integrated gallium nitride device according to claim 1, wherein The encapsulation structure further includes several temperature-sensitive elements; One of the temperature-sensitive elements is arranged on the substrate of each of the class-D audio controller and each gallium nitride device.