Power module fabrication method based on one-step connection process and related apparatus
By employing a one-step connection process in the power module, the gate and source are connected on the substrate using the same type of connection materials and components, which solves the problem of increased process and material quantity, reduces stray inductance, and improves yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ACCOPOWER SEMICON CO LTD
- Filing Date
- 2026-03-19
- Publication Date
- 2026-05-29
AI Technical Summary
Differences in the connection process between the gate and source in existing power modules lead to an increase in the number of processes and materials, making it difficult to keep them at a low level.
A one-step connection process is adopted, in which silver paste is printed on the substrate and the power chip and components are fixed. The same type of connection material is used to connect the gate and source as well as the surface of the components. The one-step connection between the gate and source is achieved by using connection components, reducing the number of processes and materials.
By reducing the number of processes and materials, stray inductance was reduced, and the yield of power modules was improved.
Smart Images
Figure CN122121728A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor technology, and in particular to a method and related equipment for manufacturing power modules based on a one-step interconnect process. Background Technology
[0002] There are various connection technologies for chips in power modules. Among them, the connection technologies for the source (S) cover aluminum wire, copper wire, aluminum strip, copper strip, and aluminum-clad copper wire bonding. However, due to size limitations, the gate (G) is mostly connected using bonding processes.
[0003] The difference in the G and S pole selection processes leads to an increase in the number of steps, and it is difficult to keep the number of materials and parts at a low level. Summary of the Invention
[0004] The main objective of this application is to propose a power module fabrication method and related equipment based on a one-step bonding process, which aims to reduce the number of processes and materials, reduce stray inductance, and improve yield by eliminating the need for separate gate bonding.
[0005] To achieve the above objectives, one aspect of this application proposes a power module fabrication method based on a one-step interconnect process, the method comprising: Silver paste is printed on the surface of the substrate, and power chips and components are mounted on the surface of the silver paste. The power chips and components are fixed on the substrate by sintering. Depending on the material morphology of the connection material, the same type of connection material is transferred to the gate and source electrodes on the surface of the power chip and the surface of the component, wherein the connection material is any one of paste soldering material, sheet soldering material, paste sintering material and sheet sintering material; Connecting components are attached to the surface of the connecting material, and according to the process requirements of the connecting material, the gate and the source are connected to the component in one step through the connecting components to obtain a power component; The power component is connected to the heat sink base plate and a housing and power terminals are installed. The power module is obtained by curing and encapsulation.
[0006] In some embodiments, transferring the same type of connection material on the gate and source of the power chip and on the surface of the component, based on the material morphology of the connection material, includes the following steps: When the material of the connection is in paste form, a partial aperture mask is used to shield the non-printed areas on the gate and source of the power chip and the surface of the components, and expose the target area to be printed. The paste-like connecting material is printed onto the target area, wherein the adhesion between the paste-like connecting material and the partial opening mask is less than the adhesion between the paste-like connecting material and the substrate.
[0007] In some embodiments, using a partial aperture mask to shield the non-printed areas on the power chip surface, including the gate and source electrodes and the surface of the components, and to expose the target areas to be printed, includes the following steps: Based on the different printing plane heights of the gate and source electrodes on the surface of the power chip and the surface of the components, corresponding local aperture masks are made to block the non-printed areas and expose the target areas that need to be printed. The process of printing the paste-like binding material onto the target area includes the following steps: The paste-like connecting material is printed onto the target area in batches according to different printing plane heights, wherein the printing plane height is the same within the same batch.
[0008] In some embodiments, transferring the same type of connection material on the gate and source of the power chip and on the surface of the component, based on the material morphology of the connection material, includes the following steps: When the connecting material is in paste form, the paste-like connecting material is sprayed onto the target areas of the power chip's gate and source electrodes and the surface of the components in the form of discrete microdroplets through a nozzle, following a preset trajectory. The agglomerated particle size of the paste-like connecting material is smaller than the nozzle orifice diameter.
[0009] In some embodiments, transferring the same type of connection material on the gate and source of the power chip and on the surface of the component, based on the material morphology of the connection material, includes the following steps: When the connecting material is in sheet form and the process requirement of the connecting material is welding, the sheet welding material is attached to the surface of the gate, the source and the component by dispensing adhesive. When the connecting material is in sheet form and the process requirement for the connecting material is sintering, the sheet sintered material is attached to the surface of the gate, the source, and the component through pre-sintering treatment.
[0010] In some embodiments, the step of connecting the gate and the source to the components in one step using the connecting components to obtain a power assembly, according to the process requirements of the connecting material, includes the following steps: When the process requirement for the connecting material is sintering, a first adhesion force is formed between the gate and the connecting component, between the source and the connecting component, and between the component and the connecting component through pre-sintering treatment to obtain a semi-finished assembly; The semi-finished component is sintered to form a second adhesion between the gate and the connecting component, between the source and the connecting component, and between the component and the connecting component, thereby obtaining a power component.
[0011] In some embodiments, the step of connecting the gate and the source to the components in one step using the connecting components to obtain a power assembly, according to the process requirements of the connecting material, includes the following steps: When the process requirement for the connecting material is welding, the connecting material on the surface of the gate, the source, and the component is heated to the melting point temperature and then cooled and solidified by reflow soldering, so that the connecting components are welded to the gate, the source, and the component to obtain a power component.
[0012] To achieve the above objectives, another aspect of this application proposes a power module fabrication system based on a one-step interconnect process, the system comprising: The first module is used to print silver paste on the surface of the substrate and attach power chips and components to the surface of the silver paste, and fix the power chips and components on the substrate by sintering. The second module is used to transfer the same type of connection material on the gate and source of the power chip and on the surface of the component, according to the material form of the connection material, wherein the connection material is any one of paste soldering material, sheet soldering material, paste sintering material and sheet sintering material; The third module is used to attach the connecting components to the surface of the connecting material, and according to the process requirements of the connecting material, to connect the gate and the source to the component in one step through the connecting components to obtain a power component; The fourth module is used to connect the power component to the heat sink base plate and install the housing and power terminals, and obtain the power module through curing and encapsulation.
[0013] To achieve the above objectives, another aspect of this application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method.
[0014] To achieve the above objectives, another aspect of the embodiments of this application proposes a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method.
[0015] To achieve the above objectives, another aspect of this application provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.
[0016] The embodiments of this application include at least the following beneficial effects: This application provides a power module fabrication method and related equipment based on a one-step bonding process. This method involves printing silver paste on the surface of a substrate and mounting power chips and components onto the surface of the silver paste, then fixing the power chips and components onto the substrate through sintering. Based on the material morphology of the bonding material, the same type of bonding material is transferred to the gate and source terminals of the power chip and the surface of the components. Bonding components are mounted on the surface of the bonding material, and according to the process requirements of the bonding material, the gate and source terminals are one-steply bonded to the components to obtain a power assembly. The power assembly is connected to a heat sink and a housing and power terminals are installed, and the power module is obtained through curing and encapsulation. The embodiments of this application can use the same process for the gate and source terminals, eliminating the need for separate bonding of the gate, reducing the number of processes and materials, and lowering stray inductance. Attached Figure Description
[0017] Figure 1 This is a flowchart of a power module fabrication method based on a one-step interconnect process provided in an embodiment of this application; Figure 2 This is a product structure diagram of the power component provided in the embodiments of this application; Figure 3 This is a schematic diagram of the chip region connection relationship provided in an embodiment of this application; Figure 4 This is a schematic diagram of the non-chip region connection relationship provided in an embodiment of this application; Figure 5 This is a schematic diagram of the spraying device provided in the embodiments of this application; Figure 6 This is a schematic diagram of the power module fabrication system based on a one-step interconnection process provided in an embodiment of this application; Figure 7 This is a schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of systems and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.
[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.
[0020] The power module fabrication method based on a one-step interconnect process provided in this application relates to the field of semiconductor technology. This method can be applied to terminals, servers, or software running on either a terminal or a server. In some embodiments, the terminal can be a smartphone, tablet, laptop, desktop computer, smart speaker, smartwatch, or in-vehicle terminal, but is not limited to these. The server can be configured as an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The server can also be a node server in a blockchain network. The software can be an application implementing the power module fabrication method based on the one-step interconnect process, but is not limited to the above forms.
[0021] This application can be used in a wide variety of general-purpose or special-purpose computer system environments or configurations. Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics devices, network PCs, minicomputers, mainframe computers, and distributed computing environments including any of the above systems or devices. This application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.
[0022] Figure 1 This is an optional flowchart of a power module fabrication method based on a one-step interconnect process provided in an embodiment of this application. Figure 1 The method may include, but is not limited to, steps S101 to S104.
[0023] Step S101: Print silver paste on the surface of the substrate and mount the power chip and components on the surface of the silver paste. Fix the power chip and components on the substrate by sintering.
[0024] Step S102: Based on the material morphology of the connection material, transfer the same type of connection material to the gate and source of the power chip and the surface of the components. The connection material is any one of paste soldering material, sheet soldering material, paste sintering material and sheet sintering material.
[0025] In step S103, the connecting components are mounted on the surface of the connecting material, and the gate and source are connected to the components in one step according to the process requirements of the connecting material to obtain the power component.
[0026] Step S104: Connect the power component to the heat sink base plate and install the housing and power terminals, and obtain the power module through curing and encapsulation.
[0027] In this embodiment, the current source electrode is connected by copper clip sintering or welding, while the gate electrode is limited by the pad size of about 0.8x0.8mm. Usually, a separate bonding process can be used to complete the interconnection process. Since the gate electrode and the source electrode need to be processed separately, the number of processes and materials increases. This embodiment can unify the processes of the gate electrode and the source electrode. There is no need to bond the gate electrode separately. Instead, the same type of connection material is applied to the surface of the gate electrode, the source electrode and the components required by the power module. Then, the required components are connected to the gate electrode and the source electrode of the power chip in one step through the connection components. The process that originally required the gate electrode and the source electrode to be connected separately is transformed into a process that can be connected in one step.
[0028] Specifically, in this embodiment, silver paste is first printed and dried on the substrate. Then, power chips and necessary components such as thermistor sensors (NTC) and gate resistors (Rg) are mounted on the surface of the silver paste. After mounting, the power chips and components are sintered to achieve the connection between the bottom of the power chips and components and the substrate.
[0029] Next, the same type of connection material is placed on the surface of the power chip and the components to be connected. In this embodiment, the connection material refers to the key material that makes electrical, thermal and mechanical connections between the power chip and the external circuit or package structure. The connection material needs to meet key performance index standards. Common key performance indicators include electrical conductivity, thermal conductivity, thermal expansion coefficient matching, mechanical strength, high / low temperature resistance, and long-term reliability.
[0030] For example, the connecting materials can be classified into paste welding materials, sheet welding materials, paste sintering materials and sheet sintering materials according to the material form and process requirements. Among them, paste and sheet are the material forms of the connecting materials, and welding and sintering are the process requirements of the connecting materials.
[0031] Sintering materials can include pressureless sintering silver paste, pressure sintering silver paste / silver film, pressureless sintering copper paste, pressure sintering copper paste / copper film, copper sheets that can be used as sintering materials, double-sided DTS, copper-tin composite solder paste, etc.
[0032] It should be noted that the process conditions used for selecting sintering materials, such as temperature and sintering pressure, should not exceed the tolerance level of the power module semi-finished product to avoid damage. To ensure that mass-produced sintering equipment can be used for this sintering technology, materials with a sintering temperature <300℃, sintering pressure <30MPa, and a sintering atmosphere of nitrogen, air, or a hydrogen mixture are generally selected.
[0033] Soldering materials can include tin-based solder paste / solder sheet, high-lead solder paste / solder sheet, TLPS solder sheet, etc.
[0034] It should be noted that the process conditions used for selecting welding materials, such as temperature and pressure, should not exceed the tolerance level of the power module semi-finished product to avoid damage. To ensure that existing welding equipment can be used for this welding technology, materials with a melting point <300℃ and welding atmospheres such as nitrogen, air, hydrogen mixture, or formic acid atmosphere are generally selected.
[0035] When transferring bonding materials to the gate and source of a power chip and to the surface of components, one of three methods can be selected from printing, spraying, and mounting, depending on the material state of the bonding materials.
[0036] Specifically, the transfer methods available for connection materials vary depending on their material state. For sheet materials with fixed dimensions, such as solder pads and DTS, they can be transferred through mounting. However, if the connection material is a fluid paste such as solder paste, it can be transferred through printing or spraying processes.
[0037] It is understandable that during the process, the materials used for the gate, source, and components should be consistent in terms of material form and process requirements so that the same process can be used to connect the gate and source in subsequent connections, so that the gate and source can use the same process, without the need to add a connection step through bonding process.
[0038] After placing connection materials on the surface of the chip and the components to be connected, mounting can achieve interconnection between the chip and the surface of the components and corresponding areas. These connection components are used to simultaneously connect the gate, source, and components, such as one-piece copper clips with integrated circuitry. During mounting, adhesive can be applied to either side of the connection surface of the connection component and the connection material. For example, adhesive can be applied to the lead of the component before mounting it onto the connection material, or adhesive can be applied to the connection material before mounting the component.
[0039] Preferably, the connecting components are made of plate copper clips. During the mounting process, one end of the plate copper clip needs to be connected to both the gate (G) and source (S) terminals of the power chip after the connection material has been transferred, and the other end needs to be connected to the components after the connection material has been transferred.
[0040] Specifically, an insulating material is locally coated on the surface of the copper clip, or the copper clip is made together with other insulating materials into a PCB-like structure, thereby ensuring that the areas that need insulation are insulated and the areas that need electrical connection are electrically connected; in this way, a single copper clip can be connected to the G, S, and D poles simultaneously.
[0041] According to the principles of electromagnetism, the larger the loop area, the greater the inductance. Using a copper clip to connect both the gate (G) and source (S) poles simultaneously can shorten the electrical connection path between the G and S poles. The reduced physical distance can decrease the current loop area, thereby reducing stray inductance.
[0042] Furthermore, after the connecting components are mounted, the gate and source can be connected to the components simultaneously in a one-step process using sintering or welding techniques, depending on the process requirements of the connecting materials, to obtain a power component with a stable electrical and mechanical connection.
[0043] Optionally, if required, the power components can be connected to the heat sink during the soldering or sintering process, and the pin connections can be completed. A ring of sealant is applied around the edge of the heat sink, and then the plastic housing is bonded. After the adhesive cures, ultrasonic / laser soldering or other processes are performed on the power terminals to connect them to the substrate, resulting in... Figure 2 The power component product structure is shown.
[0044] The chip region connection relationship in the power component is as follows: Figure 3 As shown, all materials are stacked in the following order from bottom to top: heat dissipation base plate, connection layer between heat dissipation base plate and substrate, substrate, substrate-chip connection layer, chip, copper clip-chip connection layer, and copper clip. Finally, the power module is packaged by molding and potting curing.
[0045] The connection relationships of non-chip areas in power components are as follows: Figure 4 As shown, all materials are stacked in the following order from bottom to top: heat dissipation base plate, heat dissipation base plate and substrate connection layer, substrate, copper clip and substrate connection layer, and copper clip.
[0046] In some embodiments, step S102 may include, but is not limited to, steps S201 to S202.
[0047] Step S201: When the material of the connection material is in paste form, a partial aperture mask is used to shield the non-printed areas on the gate and source of the power chip and the surface of the components, and expose the target area to be printed.
[0048] Step S202: Print the paste-like bonding material onto the target area, wherein the adhesion between the paste-like bonding material and the partial opening mask is less than the adhesion between the paste-like bonding material and the substrate.
[0049] In this embodiment, the connecting materials in paste form include paste welding materials and paste sintering materials. The paste connecting materials can be transferred by printing or spraying processes. This embodiment takes the printing process as an example to illustrate the basic process principle of paste connecting materials.
[0050] Specifically, the printing process involves using a partially perforated mask to block out non-printing areas and expose the target areas to be printed. Then, a paste-like binder material is printed onto the target areas by a stencil. After printing, lifting the stencil transfers the binder material to the areas to be bonded. Understandably, the required paste thickness can be adjusted according to the mask thickness.
[0051] It should be noted that, due to the small size of the gate, the printable area is also small. Typically, the gate of a power chip is about 0.8x0.8mm, which is smaller than the 5x5mm of common printing processes. As the printing area shrinks, the difference between the adhesion between the paste and the mask and the adhesion between the paste and the substrate will gradually decrease until the paste can no longer be transferred to the target area to be printed.
[0052] To address the challenge of printing on small areas, this embodiment selects a paste-like bonding material that meets specific printing conditions and prints it onto the G electrode. This ensures that the paste-like bonding material can be properly transferred to the target area even at small sizes. The printing conditions are such that the adhesion between the paste-like bonding material and the partially perforated mask is less than the adhesion between the paste-like bonding material and the substrate.
[0053] In some embodiments, step S201 may include, but is not limited to, step S301.
[0054] Step S301: Based on the different printing plane heights of the gate and source on the power chip surface and the surface of the components, corresponding local aperture masks are made to block the non-printed areas and expose the target areas to be printed.
[0055] Step S202 may include, but is not limited to, step S302.
[0056] Step S302: Print the paste-like connecting material onto the target area in batches according to different printing plane heights, wherein the printing plane heights of the same batch are the same.
[0057] In this embodiment, if a paste-like connecting material is to be printed on the gate of the power module, in addition to the difficulty of printing in a small area, there is also a certain height difference between the gate and the source. During printing, the target area to be transferred by the paste-like connecting material should usually be on a plane. However, the height difference between the gate and the source causes a height difference in the target area. If a mask with a 3D structure is used for printing, this height difference will introduce the problem that the mask cannot simultaneously adhere to printing areas of different heights. Therefore, printing defects are prone to occur on the side with the gap.
[0058] In view of this, this embodiment, based on the different printing plane heights of the gate, source, and components on the surface of the chip, creates a corresponding local aperture mask for each printing plane height to block the non-printed areas of the gate, source, and components at that printing plane height and expose the target area to be printed.
[0059] For different printing plane heights, the target areas with the same printing plane height are grouped according to the printing plane height and printed in the same batch. Since the target areas in the same batch are all at the same printing height, the local opening mask can fit tightly against the surface to achieve zero-gap printing and improve the yield.
[0060] For example, the chip surface is used as the reference plane for measuring height. Assuming the chip surface is 0, the distances of the gate and source on the power chip surface and the surface of the components from the horizontal plane of the substrate surface are measured to obtain several printed plane heights.
[0061] For example, if the measured height of the gate printing plane is 120nm, the source printing plane is 140nm, the NTC thermistor printing plane is 140nm, and the gate resistor is 160nm, then three partial aperture masks can be fabricated based on the printing plane heights, corresponding to 120nm, 140nm, and 160nm respectively.
[0062] Source and NTC thermistors with the same printing plane height of 140nm can have the paste-like bonding material printed on the surface of the source and NTC thermistors simultaneously in one batch using the same local aperture mask.
[0063] The gate and source electrodes, which have different printing plane heights, are each printed with paste-like connection material in different batches through a local aperture mask.
[0064] In some embodiments, step S102 may include, but is not limited to, step S401.
[0065] Step S401: When the connecting material is in paste form, the paste connecting material is sprayed onto the target areas of the power chip's gate and source electrodes and the surface of the components in the form of discrete microdroplets through a nozzle, following a preset trajectory. The agglomerated particle size of the paste connecting material is smaller than the nozzle orifice diameter.
[0066] In this embodiment, the basic principle of the process of paste-like bonding materials is explained using a spraying process as an example.
[0067] Specifically, refer to Figure 5The spraying process uses piezoelectric valves, screw valves, and impact-pin spray valves to spray paste-like binder material through nozzles in the form of discrete microdroplets, one by one. Different spraying target areas can be adjusted according to the preset spraying trajectory. The minimum spraying target area size is limited by the nozzle size.
[0068] It is understandable that the common nozzle orifice diameter is 20-200μm, which can meet the common chip gate size of 0.8x0.8mm, so the size problem can be ignored.
[0069] It should be noted that if the paste-like binder agglomerates, it can easily cause nozzle blockage or abnormal explosion points. Therefore, when selecting a paste-like binder, the agglomeration particle size of the binder must be smaller than the nozzle orifice diameter.
[0070] In some embodiments, step S102 may include, but is not limited to, steps S501 and S502.
[0071] Step S501: When the material form of the connecting material is sheet and the process requirement of the connecting material is welding, the sheet welding material is attached to the surface of the gate, source and components by dispensing.
[0072] Step S502: When the material form of the connecting material is sheet-like and the process requirement of the connecting material is sintering, the sheet-like sintered material is attached to the surface of the gate, source and components through pre-sintering treatment.
[0073] In this embodiment, the sheet-like connecting materials include sheet welding materials and sheet sintering materials. For sheet welding materials, since the process requirement for this connecting material is welding, the available connecting materials can be tin-based solder sheets, lead-paste solder sheets, TLPS solder sheets, etc. For sheet sintering materials, since the process requirement for this connecting material is sintering, the available connecting materials can be silver films, copper films, copper sheets suitable for sintering, double-sided DTS, etc.
[0074] Since the sintering process can pre-fix sheet sintered materials to the areas to be welded, such as gates, sources, and the surface of components, it is not necessary to use glue to apply adhesive to the sheet connecting materials to achieve pre-fixation.
[0075] The welding process requires first applying adhesive to the gate, source, and other components, and then attaching sheet-like welding material to the adhesive-applied areas for pre-fixation.
[0076] In some embodiments, step S103 may include, but is not limited to, steps S601 to S602.
[0077] Step S601: When the process requirement for the connection material is sintering, a first adhesion force is formed between the gate and the connection component, between the source and the connection component, and between the component and the connection component through pre-sintering treatment, to obtain a semi-finished component.
[0078] Step S602: The semi-finished component is sintered to form a second adhesion between the gate and the connecting parts, between the source and the connecting parts, and between the components and the connecting parts, thereby obtaining a power component.
[0079] In this embodiment, when the process requirement for the connecting material is sintering, the semi-finished product is temporarily shaped by pre-sintering and then connected by sintering.
[0080] Specifically, the forces that form connections during pre-sintering are mainly very fragile and temporary mechanical interlocking and van der Waals forces, while the connections formed during sintering are mainly metallic bonds formed after solid-state diffusion.
[0081] Pre-sintering involves placing the necessary connectors into the correct locations using a pick-and-place machine, establishing adhesion between the gate and the connector, the source and the connector, and between the component and the connector. This ensures no misalignment occurs before sintering. Typically, the temperature used during pick-and-place is 80-180℃, the pressure is 1-3 MPa, and the time is 1-3 seconds. After the first adhesion is established during pre-sintering, the shear force that pushes the chip away is approximately 0.04 MPa.
[0082] Sintering completes the connection of the pre-sintered semi-finished components. By further enhancing the adhesion between the gate and the connecting components, between the source and the connecting components, and between the components and the connecting components, a power component is obtained. The sintering temperature is usually 200-300℃, the pressure is 10-30Mpa, and the time is 100-1000s. After the second adhesion is formed by sintering, the shear force that pushes the chip off is about 40~80Mpa.
[0083] In some embodiments, step S103 may include, but is not limited to, step S701.
[0084] Step S701: When the process requirement for the connection material is welding, the connection material on the gate, source, and component surfaces is heated to the melting point temperature and then cooled and solidified by reflow soldering, so that the connection components are welded onto the gate, source, and components to obtain a power component.
[0085] In this embodiment, when the process requirement for the connection material is welding, multiple connections can be completed simultaneously through reflow soldering. Since the connection materials on the gate, source, and component surfaces are of the same type, they can be completed synchronously in one process.
[0086] Specifically, the entire stacked structure with the attached connecting components is placed into the reflow soldering circuit for heating and soldering. The reflow oven is a multi-temperature zone oven that melts the connecting materials and forms reliable solder joints with the welding area by precisely controlling the temperature. The temperature profile typically includes four stages: preheating, holding, reflowing, and cooling.
[0087] During the preheating stage, the temperature is gradually increased to a suitable welding temperature to avoid thermal stress damaging electronic components.
[0088] During the heat preservation stage, further heating is carried out to ensure that the gate, source, components, and connecting parts reach the same temperature before entering the reflow area, thus avoiding poor soldering caused by high-temperature thermal shock in the reflow area.
[0089] During the reflow stage, heating to the melting point temperature causes the bonding material on the gate, source, and component surfaces to diffuse and form an electrical connection with the bonding components mounted on the bonding material.
[0090] During the cooling phase, the temperature of the solder joints is rapidly cooled to solidify them into stable solder joints. Once the solder joints have cooled and solidified, permanent connections can be formed between the connecting components and the gate, source, and other components, resulting in a power assembly.
[0091] It is understood that this embodiment utilizes a bonding material, enabling the gate and source to be connected using the same reflow soldering process, eliminating the need for a separate bonding process, reducing the number of steps, and achieving a one-step connection between the gate and source.
[0092] The following is a detailed description and explanation of the solutions in the embodiments of the present invention, using specific application examples: The overall connection method of this application embodiment is as follows: printing silver paste on the substrate, drying the silver paste, mounting the chip and required components on the surface of the silver paste, sintering the chip and components onto the substrate, transferring the connection material on the S / G poles of the chip and the surface of the components to be connected, attaching the copper clip to the connection material, and connecting the copper clip to the circuit through sintering, reflow or other processes.
[0093] If the connecting material is a fixed-size material such as solder pad or DTS, it can only be transferred to the chip through mounting. If the connecting material is a fluid material such as solder paste, it can be transferred to the chip through printing or spraying processes. The component copper clips are transferred using mounting processes, and then the copper clips are connected to the circuit using soldering, sintering or other processes.
[0094] Unlike current methods that use bonding wires to connect the gate (G) to the circuit, the source (S) can be connected to the circuit via distributed connection processes such as aluminum wire / copper wire / aluminum strip / copper strip / aluminum-clad copper wire bonding, copper clip sintering / welding, etc. This embodiment utilizes connection materials and adopts a one-step connection method to connect copper clips or components that need to be connected to the gate (G) and source (S) of the chip. It can ignore the size problem of the gate (G) and complete the connection through full sintering or welding to complete the fabrication of the power module.
[0095] Specifically, depending on the size of the gate (G) and source (S) electrodes, connection materials of specific dimensions can be transferred to the G and S regions respectively. This requires connections of varying heights and areas on the chip, component, and substrate surfaces. Furthermore, the material used for connection on the chip surface needs to be fabricated to approximate the size of the G / S electrodes and the component connection surfaces; a common G electrode size is approximately 0.8 x 0.8 mm.
[0096] For example, a spray coating process can be used to transfer the paste-like connection material to a specific area. Alternatively, if a soldering method is used, solder paste can be sprayed onto the soldering area first, followed by mounting the copper clips and then performing a one-step reflow soldering; in this case, the gate and source electrodes use the same spray coating process for solder paste application. This one-step connection, using the same process for both gate and source electrodes, offers advantages in terms of shortening the process steps compared to using adhesive brushing for the source electrode and dispensing for the gate electrode.
[0097] Alternatively, if it is a solder sheet material, an integrated mounting and dispensing device can be configured to fix it with adhesive. The steps are: dispensing adhesive on the chip / component surface, mounting the solder sheet material, dispensing adhesive on the solder sheet material, mounting and bonding the components, and reflow soldering the components to the circuit.
[0098] Alternatively, the steps for soldering sheet materials can also be: applying adhesive to the chip / component surface, mounting the sheet materials, applying adhesive to the component leads, mounting and bonding the components, and reflow soldering the components to the circuit.
[0099] If the soldering paste material is used, the dispensing integration equipment can be reduced, and the paste material itself can be used for bonding. The steps are: printing / spraying on the surface of the chip / component, mounting and bonding the components, and reflow soldering the components to the circuit.
[0100] Based on the aforementioned three transfer methods and two connection processes, the following six process routes can be derived: (1) Printing of paste sintering material - (baking) - copper clamp mounting - sintering.
[0101] (2) Printing of paste-like soldering material - copper clip mounting - reflow soldering.
[0102] (3) Sheet sintering material mounting - copper clip mounting - sintering.
[0103] (4) Dispensing - Sheet welding and mounting - Dispensing - Copper clip mounting - Reflow soldering.
[0104] (5) Spraying of paste sintering material - (baking) - copper clamp mounting - sintering.
[0105] (6) Spraying of paste-like welding material - copper clip mounting - reflow soldering.
[0106] Both (1) and (2) use printing technology. The difference is that (1) uses sintering material, while (2) uses welding material. If the material used can be used for pressureless sintering, the baking process in process (1) can be omitted. In this case, the number of processes in (1) and (2) is the same.
[0107] When using the printing process, the main challenges are printing at very small G-sizes and printing at different heights: for printing at small sizes, it is necessary to verify the minimum size at which the paste used can complete the demolding and whether this size can meet the requirements of the G-size; for printing at different heights, it is difficult to achieve simultaneous bonding between different printing heights and the stencil, but it is possible to consider printing different height areas separately, thereby eliminating the problem that the stencil and printing surfaces at different heights cannot be bonded at the same time.
[0108] The connecting materials used in (3) and (4) are both sheet materials. Since the sintering process can be used to pre-fix the sintered material to the required area through pre-sintering, it is not necessary to use glue to pre-fix the sheet material as in the welding process.
[0109] The paste materials used in (5) and (6) are more demanding than those used in (1) and (2), and the materials used must meet the following requirements: 1. Agglomerated particle size < nozzle orifice diameter, with common nozzle orifice diameters ranging from 20 to 200 μm.
[0110] 2. The viscosity is moderate, and it can self-level after spraying without serious overflow. The viscosity of commonly used materials is 5-30 Pa·S.
[0111] The basic principle of the spraying process is as follows: air pressure is used to squeeze the paste-like connecting material under the impact pin, and then the impact pin is controlled by the piezoelectric valve to squeeze the paste-like connecting material out of the nozzle, thereby transferring the connecting material to the spraying area.
[0112] Based on the principle of spraying process, if the paste-like binder material clumps together, it can easily cause nozzle blockage or abnormal explosion points.
[0113] When using a spray coating process, the equipment typically includes the following configurations: 1. Identification camera; 2. Nozzle; 3. Piezoelectric valve, screw valve, jet valve, etc.; 4. Impact pin; 5. Cooling device; 6. Feeding device; 7. Electronic scale.
[0114] Compared to printing, the main advantages of spray coating are as follows: 1. It can be used for spraying small sizes of 0.8x0.8mm.
[0115] 2. Compatible with spraying at different heights.
[0116] 3. The position of the connecting materials is better.
[0117] In summary, the power module fabrication method based on a one-step connection process provided in this application uses a copper clip for the gate (G) and source (S) terminals of the chip during the fabrication process, and forms a connection with other areas through a one-step process. This method has good operability and reliability, and can also reduce the number of processes and materials, reduce costs, and improve yield. By connecting the chip's G, S, and D terminals simultaneously with the chip using a chip-type copper clip, stray inductance can be effectively reduced.
[0118] Reference Figure 6 This application also provides a power module fabrication system based on a one-step interconnect process, which can implement the above-described method. The system includes: The first module is used to print silver paste on the surface of the substrate and mount the power chip and components on the surface of the silver paste, and fix the power chip and components on the substrate through sintering.
[0119] The second module is used to transfer the same type of connection material on the gate and source of the power chip and on the surface of the components, according to the material form of the connection material. The connection material is any one of paste soldering material, sheet soldering material, paste sintering material and sheet sintering material.
[0120] The third module is used to mount the connecting components onto the surface of the connecting material, and according to the process requirements of the connecting material, to connect the gate and source to the components in one step to obtain the power component.
[0121] The fourth module is used to connect the power components to the heat sink base plate and install the housing and power terminals, and obtain the power module through curing and encapsulation.
[0122] It is understood that the content of the above method embodiments is applicable to this system embodiment. The specific functions implemented in this system embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.
[0123] This application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method. This electronic device can be any smart terminal, including tablet computers, in-vehicle computers, etc.
[0124] It is understood that the content of the above method embodiments is applicable to this device embodiment. The specific functions implemented by this device embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.
[0125] Reference Figure 7 , Figure 7 The hardware structure of an electronic device according to another embodiment is illustrated. The electronic device includes: The processor 901 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application.
[0126] The memory 902 can be implemented as a read-only memory (ROM), static storage device, dynamic storage device, or random access memory (RAM). The memory 902 can store the operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 902 and is called and executed by the processor 901 using the methods described in the embodiments of this application.
[0127] The input / output interface 903 is used to implement information input and output.
[0128] The communication interface 904 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).
[0129] Bus 905 transmits information between various components of the device, such as processor 901, memory 902, input / output interface 903, and communication interface 904.
[0130] The processor 901, memory 902, input / output interface 903, and communication interface 904 are connected to each other within the device via bus 905.
[0131] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method.
[0132] It is understood that the content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.
[0133] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.
[0134] It is understood that the content of the above method embodiments is applicable to the embodiments of this program product. The specific functions implemented by the embodiments of this program product are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.
[0135] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.
[0136] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.
[0137] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.
[0138] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.
[0139] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.
[0140] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0141] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.
[0142] In the embodiments provided in this application, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between systems or units may be electrical, mechanical, or other forms.
[0143] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.
[0144] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.
[0145] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0146] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.
Claims
1. A method for manufacturing a power module based on a one-step interconnect process, characterized in that, The method includes the following steps: Silver paste is printed on the surface of the substrate, and power chips and components are mounted on the surface of the silver paste. The power chips and components are fixed on the substrate by sintering. Depending on the material morphology of the connection material, the same type of connection material is transferred to the gate and source electrodes on the surface of the power chip and the surface of the component, wherein the connection material is any one of paste soldering material, sheet soldering material, paste sintering material and sheet sintering material; Connecting components are attached to the surface of the connecting material, and according to the process requirements of the connecting material, the gate and the source are connected to the component in one step through the connecting components to obtain a power component; The power component is connected to the heat sink base plate and a housing and power terminals are installed. The power module is obtained by curing and encapsulation.
2. The method according to claim 1, characterized in that, The step of transferring the same type of connection material on the gate and source electrodes of the power chip and on the surface of the components, based on the material morphology of the connection material, includes the following steps: When the material of the connection is in paste form, a partial aperture mask is used to shield the non-printed areas on the gate and source of the power chip and the surface of the components, and expose the target area to be printed. The paste-like connecting material is printed onto the target area, wherein the adhesion between the paste-like connecting material and the partial opening mask is less than the adhesion between the paste-like connecting material and the substrate.
3. The method according to claim 2, characterized in that, The method of using a partial aperture mask to shield the non-printed areas on the power chip surface, including the gate and source electrodes, and the surface of the components, while exposing the target areas to be printed, includes the following steps: Based on the different printing plane heights of the gate and source electrodes on the surface of the power chip and the surface of the components, corresponding local aperture masks are made to block the non-printed areas and expose the target areas that need to be printed. The process of printing the paste-like binding material onto the target area includes the following steps: The paste-like connecting material is printed onto the target area in batches according to different printing plane heights, wherein the printing plane height is the same within the same batch.
4. The method according to claim 1, characterized in that, The step of transferring the same type of connection material on the gate and source electrodes of the power chip and on the surface of the components, based on the material morphology of the connection material, includes the following steps: When the connecting material is in paste form, the paste-like connecting material is sprayed onto the target areas of the power chip's gate and source electrodes and the surface of the components in the form of discrete microdroplets through a nozzle, following a preset trajectory. The agglomerated particle size of the paste-like connecting material is smaller than the nozzle orifice diameter.
5. The method according to claim 1, characterized in that, The step of transferring the same type of connection material on the gate and source electrodes of the power chip and on the surface of the components, based on the material morphology of the connection material, includes the following steps: When the connecting material is in sheet form and the process requirement of the connecting material is welding, the sheet welding material is attached to the surface of the gate, the source and the component by dispensing adhesive. When the connecting material is in sheet form and the process requirement for the connecting material is sintering, the sheet sintered material is attached to the surface of the gate, the source, and the component through pre-sintering treatment.
6. The method according to claim 1, characterized in that, The step of connecting the gate and the source to the components in one step using the connecting components, according to the process requirements of the connecting material, to obtain a power component, includes the following steps: When the process requirement for the connecting material is sintering, a first adhesion force is formed between the gate and the connecting component, between the source and the connecting component, and between the component and the connecting component through pre-sintering treatment to obtain a semi-finished assembly; The semi-finished component is sintered to form a second adhesion between the gate and the connecting component, between the source and the connecting component, and between the component and the connecting component, thereby obtaining a power component.
7. The method according to claim 1, characterized in that, The step of connecting the gate and the source to the components in one step using the connecting components, according to the process requirements of the connecting material, to obtain a power component, includes the following steps: When the process requirement for the connecting material is welding, the connecting material on the surface of the gate, the source, and the component is heated to the melting point temperature and then cooled and solidified by reflow soldering, so that the connecting components are welded to the gate, the source, and the component to obtain a power component.
8. A power module fabrication system based on a one-step connection process, characterized in that, The system includes: The first module is used to print silver paste on the surface of the substrate and attach power chips and components to the surface of the silver paste, and fix the power chips and components on the substrate by sintering. The second module is used to transfer the same type of connection material on the gate and source of the power chip and on the surface of the component, according to the material form of the connection material, wherein the connection material is any one of paste soldering material, sheet soldering material, paste sintering material and sheet sintering material; The third module is used to attach the connecting components to the surface of the connecting material, and according to the process requirements of the connecting material, to connect the gate and the source to the component in one step through the connecting components to obtain a power component; The fourth module is used to connect the power component to the heat sink base plate and install the housing and power terminals, and obtain the power module through curing and encapsulation.
9. An electronic device, characterized in that, The electronic device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method according to any one of claims 1 to 7.
10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 7.