Silicon carbide diode with inverted packaging structure

Abstract

The invention relates to a silicon carbide diode with an inverted packaging structure. Comprising a silicon carbide diode core and a shell wrapping the silicon carbide diode core. The silicon carbide diode core comprises a silicon carbide diode chip, and a silicon carbide diode chip electrode is arranged below the silicon carbide diode chip; a metal interconnection area is arranged below the silicon carbide diode chip electrode, and a packaging frame is arranged below the metal interconnection area. According to the silicon carbide diode of the inverted packaging structure, materials are selected, the reasonable structure is designed, the silicon carbide diode chip electrode and the packaging frame are connected together through the metal interconnection area, and compared with conventional routing connection, the area of the silicon carbide diode chip electrode and the area of the packaging frame are more effectively utilized; the large contact area enables the carbon silicon carbide diode chip electrode and the packaging frame to have extremely low resistance, and the loss of the device can be remarkably reduced during the operation period of the device.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor packaging, and particularly to a novel inverted packaging structure of a silicon carbide diode. Background Art

[0002] Traditional silicon-based Schottky diodes have problems such as high on-state voltage drop and slow switching speed in high-frequency applications, which limit their use in high-power density applications. In order to improve the efficiency and reliability of power electronic systems, a novel silicon carbide diode is needed, which can effectively solve the thermal resistance problem of traditional packaging structures in high-frequency applications and improve the heat dissipation efficiency and electrical performance of devices. With the continuous development of power electronic technology, the performance requirements for power semiconductor devices are getting higher and higher.

[0003] Silicon carbide diodes have received extensive attention in medium and high-power application fields due to their advantages such as high switching speed and low reverse recovery charge. However, traditional packaging structures have certain limitations in terms of heat dissipation performance, size, and reliability. For example, the thermal resistance of traditional packaging structures is relatively large, resulting in an increase in device temperature during operation, which affects its performance and lifespan; at the same time, the size of traditional packaging structures is relatively large, which is not conducive to the miniaturization and integration of electronic devices. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a silicon carbide diode with an inverted packaging structure. The diode includes a silicon carbide diode chip, a frame metal electrode, and a packaging material. Among them, positive and negative metal electrodes are provided on the front surface of the silicon carbide diode chip, and conductive paste or solder is used to fix the positive and negative metal electrodes of the silicon carbide diode chip to the frame metal electrode to form an electrical connection. The outer packaging materials such as plastic encapsulant solidify the entire structure into one body, playing a good protective role. The present invention aims to provide a silicon carbide diode with an inverted packaging structure, which improves the heat dissipation efficiency and electrical performance of the device by optimizing the packaging structure, reduces the packaging volume, and meets the requirements of future power electronic systems for high-efficiency, high-reliability, and miniaturized and integrated devices.

[0005] The technical solution of the present invention is as follows:

[0006] A silicon carbide diode with an inverted packaging structure includes a silicon carbide diode core and a housing covering the silicon carbide diode core;

[0007] The silicon carbide diode core includes a silicon carbide diode chip, and a silicon carbide diode chip electrode is provided below the silicon carbide diode chip;

[0008] A metal interconnection area is provided below the silicon carbide diode chip electrode, and a packaging frame is provided below the metal interconnection area.

[0009] Preferably according to the present invention, the electrodes of the silicon carbide diode chip include a positive electrode and a negative electrode, both of which are located on the same plane, facilitating the flip-chip packaging onto the corresponding metal electrode positions of the packaging frame, and the other side is the electrode-free surface.

[0010] Preferably according to the present invention, the metal interconnecting region includes a positive electrode interconnecting region and a negative electrode interconnecting region, corresponding to the positive electrode and the negative electrode of the silicon carbide diode chip electrodes.

[0011] Preferably according to the present invention, the material of the metal interconnecting region is conductive paste or solder, including but not limited to gold-tin alloy (for example: eutectic gold 80%, tin 20%), fully sintered nano-silver paste (for example: containing 96% silver by mass, containing silver nano and micron particles), etc., which are pad-shaped materials that are easy to coat or precisely position, can be melted after heating, and have excellent conductive characteristics and mechanical strength after curing, which can ensure an extremely low resistance between the silicon carbide diode chip electrodes and the packaging frame electrodes, and can provide sufficient support strength to ensure a stable mechanical connection between the silicon carbide diode chip and the packaging frame, without deformations such as bending and twisting.

[0012] Preferably according to the present invention, the packaging frame includes a positive electrode pad and a negative electrode pad, corresponding to the positive electrode and the negative electrode of the silicon carbide diode chip electrodes. After connecting the positive electrode and the negative electrode of the silicon carbide diode chip electrodes, they are used as the electrodes after packaging.

[0013] More preferably, the sizes of the positive electrode pad and the negative electrode pad are larger than the positive electrode and the negative electrode of the silicon carbide diode chip electrodes. After the silicon carbide diode chip and the packaging frame are centered and aligned, the left edge of the left pad of the packaging frame exceeds the left edge of the left electrode of the silicon carbide diode chip, and the right edge of the right pad of the packaging frame exceeds the right edge of the right electrode of the silicon carbide diode chip, but does not reach the center line of the silicon carbide diode chip and the packaging frame; the layouts of the positive electrode pad and the negative electrode pad are left-right mirror symmetric about the center line.

[0014] Preferably according to the present invention, the housing is a plastic encapsulation housing, which completely covers the silicon carbide diode core, and only the packaging frame is exposed, and is used as the electrode of the flip-chip packaged silicon carbide diode. Among them, the plastic encapsulation housing completely covers the electrode-free surface of the silicon carbide diode chip, and exceeds the width of the packaging frame in the front, back, left, and right sides. The bottom surface is flush with the lower surface of the packaging frame around the periphery without overflow glue overlapping coverage. The center part of the bottom surface completely fills the gaps between the silicon carbide diode chip electrodes, the gaps between the metal interconnecting regions, and the gaps between the packaging frames, and the lower surface is flush with the lower surface of the packaging frame without overflow glue overlapping coverage.

[0015] Preferably according to the present invention, the housing includes a plastic encapsulant housing, an insulating heat-conducting sheet, and a heat sink frame located above the insulating heat-conducting sheet; the plastic encapsulant housing covers the side and bottom of the silicon carbide diode core, and only the encapsulation frame is exposed at the bottom, which is used as the electrode of the silicon carbide diode with an inverted packaging structure. The insulating heat-conducting sheet and the heat sink frame are embedded in the center of the top of the plastic encapsulant housing and cover the top of the silicon carbide diode core.

[0016] Preferably according to the present invention, the housing includes a plastic encapsulant housing, a heat sink frame embedded in the center of the top of the plastic encapsulant housing, an insulating heat-conducting sheet located above the heat sink frame, and a heat sink located above the insulating heat-conducting sheet; the plastic encapsulant housing covers the side and bottom of the silicon carbide diode core, and only the encapsulation frame is exposed at the bottom, which is used as the electrode of the silicon carbide diode with an inverted packaging structure. The heat sink frame, the insulating heat-conducting sheet, and the heat sink cover the top of the silicon carbide diode core.

[0017] The encapsulation method of the silicon carbide diode with the above inverted packaging structure includes the following steps:

[0018] Coat or fix the metal interconnect area material on the surface of the cleaned encapsulation frame to obtain an encapsulation frame with a formed metal interconnect area;

[0019] Then take the silicon carbide diode chip and place the electrodes of the silicon carbide diode chip on the encapsulation frame with a formed metal interconnect area according to the positive and negative correspondence relationship. After heating or pressurizing or heating and pressurizing simultaneously, connect the electrodes of the silicon carbide diode chip and the encapsulation frame into an integral structure through the metal interconnect area to form a good electrical connection, and obtain a silicon carbide diode core;

[0020] Finally, place the silicon carbide diode core in a molding press for encapsulation glue. After perfusion, pressurization, heating, and curing, an inverted packaging structure of the silicon carbide diode is obtained.

[0021] For the details not elaborated in the present invention, reference can be made to the prior art.

[0022] Beneficial effects:

[0023] 1. The present invention provides a silicon carbide diode with an inverted packaging structure, which effectively improves the heat dissipation efficiency and stability of the silicon carbide diode device through coplanar electrodes and inverted packaging, reduces the on-state voltage drop of the silicon carbide diode device, and prolongs the service life of the silicon carbide diode device.

[0024] 2. The silicon carbide diode with an inverted packaging structure provided by the present invention selects appropriate materials and designs a reasonable structure. The metal interconnection area is used to connect the electrodes of the silicon carbide diode chip to the packaging frame. Compared with the conventional wire bonding connection, it makes more effective use of the areas of the electrodes of the silicon carbide diode chip and the packaging frame. The larger contact area results in extremely low resistance between the electrodes of the silicon carbide diode chip and the packaging frame, which can significantly reduce the losses of the device during operation. At the same time, this structure avoids the problem of reserving sufficient wire routing space required by wire bonding connection, can reduce the packaging thickness of the device, effectively improve the switching speed of the silicon carbide diode device, increase the efficiency of the silicon carbide diode device, reduce the packaging volume, and is beneficial to the miniaturization and integration of electronic devices.

[0025] 3. The present invention has developed a method for inverting the packaging of silicon carbide diodes, realizing the mass production of silicon carbide diodes with an inverted packaging structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of the silicon carbide diode with an inverted packaging structure of the present invention.

[0027] Figure 2 It is a process flow chart of the packaging of the silicon carbide diode with an inverted packaging structure of the present invention. Figure 3 It is a schematic structural diagram of the silicon carbide diode with an inverted packaging structure described in Embodiment 3. Figure 4 It is a schematic structural diagram of the silicon carbide diode with an inverted packaging structure described in Embodiment 4.

[0028] In the figure: 1 - silicon carbide diode chip; 2 - electrodes of the silicon carbide diode chip; 3 - metal interconnection area; 4 - packaging frame; 5 - plastic encapsulation shell; 6 - insulating and heat-conducting sheet; 7 - heat sink holder; 8 - heat sink. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this invention are further described below in conjunction with the accompanying drawings in the embodiments, but not limited thereto. For those not elaborated in detail in the present invention, they are all conventional techniques in the art.

[0030] Embodiment 1

[0031] As Figure 1 shown, a silicon carbide diode with an inverted packaging structure includes a silicon carbide diode core and a shell covering the silicon carbide diode core;

[0032] The silicon carbide diode core includes a silicon carbide diode chip 1, and below the silicon carbide diode chip 1 is a silicon carbide diode chip electrode 2; below the silicon carbide diode chip electrode 2 is provided a metal interconnection region 3, and below the metal interconnection region 3 is provided a packaging frame 4.

[0033] The silicon carbide diode chip electrode 2 includes a positive electrode and a negative electrode, both of which are located on the same plane, facilitating the flip-chip packaging to the corresponding metal electrode positions of the packaging frame, and the other side is the electrode-free surface.

[0034] The metal interconnection region 3 includes a positive electrode interconnection region and a negative electrode interconnection region, corresponding to the positive electrode and the negative electrode of the silicon carbide diode chip electrode 2.

[0035] The material of the metal interconnection region 3 is gold-tin alloy (eutectic gold 80%, tin 20%), which is easy to coat and has excellent electrical conductivity and mechanical strength after curing. It can ensure that the resistance between the silicon carbide diode chip electrode and the packaging frame electrode is extremely low, and can provide sufficient support strength to ensure a stable mechanical connection between the silicon carbide diode chip and the packaging frame, without deformation such as bending and twisting.

[0036] The packaging frame includes a positive electrode pad and a negative electrode pad, corresponding to the positive electrode and the negative electrode of the silicon carbide diode chip electrode 2. After connecting the positive electrode and the negative electrode of the silicon carbide diode chip electrode 2, it is used as the electrode after packaging. Among them, the sizes of the positive electrode pad and the negative electrode pad are larger than the positive electrode and the negative electrode of the silicon carbide diode chip electrode 2. After the silicon carbide diode chip 1 and the packaging frame 4 are centered and aligned, the left edge of the left pad of the packaging frame 4 exceeds the left edge of the left electrode of the silicon carbide diode chip 1, and the right edge of the right pad of the packaging frame 4 exceeds the right edge of the right electrode of the silicon carbide diode chip 1, but does not reach the center line of the silicon carbide diode chip and the packaging frame; the layout of the positive electrode pad and the negative electrode pad is left-right mirror symmetric about the center line.

[0037] The housing is a plastic encapsulation housing 5, which completely covers the silicon carbide diode core, and only the packaging frame 4 is exposed, used as the electrode of the flip-chip packaged silicon carbide diode. Among them, the plastic encapsulation housing 5 completely covers the electrode-free surface of the silicon carbide diode chip 1, exceeding the width of the packaging frame in the front, back, left, and right directions, and the bottom surface is flush with the lower surface of the packaging frame without overflow glue overlapping coverage. The center part of the bottom surface completely fills the gaps between the silicon carbide diode chip electrodes 2, the gaps between the metal interconnection regions, and the gaps between the packaging frames, and the lower surface is flush with the lower surface of the packaging frame without overflow glue overlapping coverage.

[0038] Example 2

[0039] The packaging method of the flip-chip packaged silicon carbide diode described in Example 1 includes the following steps:

[0040] Coat the surface of the cleaned encapsulation frame 4 with a gold-tin alloy to obtain the encapsulation frame 4 forming the metal interconnection region 3;

[0041] Then, take the silicon carbide diode chip 1 and place the silicon carbide diode chip electrodes 2 on the encapsulation frame 4 forming the metal interconnection region 3 according to the positive-negative correspondence relationship. At the same time, heat and apply pressure to connect the silicon carbide diode chip electrodes 2 and the encapsulation frame 4 into an integral structure through the metal interconnection region 3 to form a good electrical connection, obtaining the silicon carbide diode core;

[0042] Finally, place the silicon carbide diode core in a molding press for encapsulation glue. After perfusion, pressurization, heating, and curing, a silicon carbide diode with an inverted packaging structure is obtained.

[0043] Example 3

[0044] As Figure 3 shown, a silicon carbide diode with an inverted packaging structure includes a silicon carbide diode core and a housing covering the silicon carbide diode core;

[0045] The silicon carbide diode core includes a silicon carbide diode chip 1, and below the silicon carbide diode chip 1 is a silicon carbide diode chip electrode 2; below the silicon carbide diode chip electrode 2 is provided a metal interconnection region 3, and below the metal interconnection region 3 is provided an encapsulation frame 4.

[0046] The silicon carbide diode chip electrode 2 includes a positive electrode and a negative electrode, both of which are located on the same plane, facilitating inverted packaging to the corresponding metal electrode positions of the encapsulation frame, and the other side is an electrode-free surface.

[0047] The metal interconnection region 3 includes a positive electrode interconnection region and a negative electrode interconnection region, corresponding to the positive electrode and negative electrode of the silicon carbide diode chip electrode 2.

[0048] The material of the metal interconnection region 3 is fully sintered nano-silver glue (silver content by mass is 96%), which is easy to coat and has excellent conductive characteristics and mechanical strength after curing. It can ensure that there is an extremely low resistance between the silicon carbide diode chip electrode and the encapsulation frame electrode, and can provide sufficient support strength to ensure a stable mechanical connection between the silicon carbide diode chip and the encapsulation frame, without deformations such as bending and twisting.

[0049] The encapsulation frame includes a positive electrode pad and a negative electrode pad, which correspond to the positive and negative electrodes of the silicon carbide diode chip electrode 2. After connecting the positive and negative electrodes of the silicon carbide diode chip electrode 2, they are used as the electrodes after encapsulation. Among them, the sizes of the positive electrode pad and the negative electrode pad are larger than those of the positive and negative electrodes of the silicon carbide diode chip electrode 2. After the silicon carbide diode chip 1 and the encapsulation frame 4 are centered and aligned, the left edge of the left pad of the encapsulation frame 4 exceeds the left edge of the left electrode of the silicon carbide diode chip 1, and the right edge of the right pad of the encapsulation frame 4 exceeds the right edge of the right electrode of the silicon carbide diode chip 1, but does not reach the center line of the silicon carbide diode chip and the encapsulation frame; the layout of the positive electrode pad and the negative electrode pad is left-right mirror-symmetrical about the center line.

[0050] The housing includes a plastic encapsulation housing 5, an insulating heat-conducting sheet 6, and a heat sink frame 7 located above the insulating heat-conducting sheet 6; the plastic encapsulation housing 5 covers the side and bottom of the silicon carbide diode core, and only the encapsulation frame 4 is exposed at the bottom, which is used as the electrode of the flip-chip packaged silicon carbide diode. The insulating heat-conducting sheet 6 and the heat sink frame 7 are embedded in the center of the top of the plastic encapsulation housing 5 to cover the top of the silicon carbide diode core.

[0051] Embodiment 4

[0052] As Figure 4 shown, a silicon carbide diode with a flip-chip structure has a specific structure as described in Embodiment 1. The difference is that the housing includes a plastic encapsulation housing 5, a heat sink frame 7 embedded in the center of the top of the plastic encapsulation housing 5, an insulating heat-conducting sheet 6 located above the heat sink frame 7, and a heat sink 8 located above the insulating heat-conducting sheet 6; the plastic encapsulation housing 5 covers the side and bottom of the silicon carbide diode core, and only the encapsulation frame 4 is exposed at the bottom, which is used as the electrode of the flip-chip packaged silicon carbide diode. The heat sink frame 7, the insulating heat-conducting sheet 6, and the heat sink 8 cover the top of the silicon carbide diode core.

[0053] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined arbitrarily.

Claims

1. A flip-chip structured silicon carbide diode, characterized in that, It includes a silicon carbide diode core and a housing that encapsulates the silicon carbide diode core; The silicon carbide diode core includes a silicon carbide diode chip, and below the silicon carbide diode chip is the silicon carbide diode chip electrode; Below the silicon carbide diode chip electrode is provided a metal interconnect region, and below the metal interconnect region is provided a package frame.

2. The silicon carbide diode with an inverted package structure as claimed in claim 1, wherein, The silicon carbide diode chip electrode includes a positive electrode and a negative electrode, and both are located on the same plane.

3. The silicon carbide diode with an inverted packaging structure as claimed in claim 1, wherein The metal interconnect region includes a positive electrode interconnect region and a negative electrode interconnect region, corresponding to the positive electrode and the negative electrode of the silicon carbide diode chip electrode.

4. The silicon carbide diode with an inverted packaging structure according to claim 1, characterized in that, The material of the metal interconnect region is gold-tin alloy or fully sintered nano-silver paste.

5. The silicon carbide diode with an inverted packaging structure as claimed in claim 1, wherein The package frame includes a positive electrode pad and a negative electrode pad, corresponding to the positive electrode and the negative electrode of the silicon carbide diode chip electrode.

6. The silicon carbide diode with an inverted package structure according to claim 5, characterized in that, The sizes of the positive electrode pad and the negative electrode pad are larger than those of the positive electrode and the negative electrode of the silicon carbide diode chip electrode. After the silicon carbide diode chip and the package frame are centered and aligned, the left edge of the left pad of the package frame exceeds the left edge of the left electrode of the silicon carbide diode chip, and the right edge of the right pad of the package frame exceeds the right edge of the right electrode of the silicon carbide diode chip, but does not reach the center line of the silicon carbide diode chip and the package frame; the layout of the positive electrode pad and the negative electrode pad is left-right mirror symmetric about the center line.

7. The silicon carbide diode with an inverted packaging structure according to claim 1, characterized in that, The housing is a plastic encapsulation housing, which completely encapsulates the silicon carbide diode core, and only the package frame is exposed.

8. The silicon carbide diode with an inverted packaging structure according to claim 1, wherein The housing includes a plastic encapsulation housing, an insulating heat-conducting sheet, and a heat sink holder located above the insulating heat-conducting sheet; the plastic encapsulation housing encapsulates the side and bottom of the silicon carbide diode core, and only the package frame is exposed at the bottom for use as the electrode of the inverted package structure silicon carbide diode; the insulating heat-conducting sheet and the heat sink holder are embedded in the center of the top of the plastic encapsulation housing to encapsulate the top of the silicon carbide diode core.

9. The silicon carbide diode with an inverted package structure as claimed in claim 1, wherein, The housing includes a plastic encapsulation housing, a heat sink holder embedded in the center of the top of the plastic encapsulation housing, an insulating heat-conducting sheet located above the heat sink holder, and a heat sink located above the insulating heat-conducting sheet; the plastic encapsulation housing encapsulates the side and bottom of the silicon carbide diode core, and only the package frame is exposed at the bottom for use as the electrode of the inverted package structure silicon carbide diode; the heat sink holder, the insulating heat-conducting sheet and the heat sink encapsulate the top of the silicon carbide diode core.

10. The encapsulation method of the silicon carbide diode with the flip-chip structure according to any one of claims 1 to 9, characterized in that, It includes the following steps: Coat or fix the metal interconnect region material on the surface of the cleaned package frame to obtain a package frame with a formed metal interconnect region; Then take a silicon carbide diode chip and place the silicon carbide diode chip electrode on the package frame with a formed metal interconnect region according to the positive-negative correspondence relationship. After heating or pressurizing or heating and pressurizing simultaneously, connect the silicon carbide diode chip electrode and the package frame into an integral structure through the metal interconnect region to form a good electrical connection, and obtain a silicon carbide diode core; Finally, place the silicon carbide diode core in a molding press for encapsulation glue. After perfusion, pressurization, heating, and curing, an inverted package structure silicon carbide diode is obtained.

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