High-voltage silicon-based MOSFET structure with heat dissipation function

Abstract

The utility model discloses a high pressure silicon base MOSFET structure with heat dissipation function relates to the technical field of semiconductor power device, this high pressure silicon base MOSFET structure with heat dissipation function, including epitaxial layer, metal sheet, gate oxygen and substrate structure, the metal sheet and gate oxygen are located epitaxial layer top, and gate oxygen is located between metal sheet, substrate structure is located epitaxial layer bottom, the bottom of epitaxial layer is seted up and is inserted hole. This high pressure silicon base MOSFET structure with heat dissipation function, through " backing plate - insulation heat conducting layer - metal heat dissipation layer " three layer composite structure, insulation heat conducting layer insulates high -voltage leakage, and metal heat dissipation layer disperses heat rapidly, and compared with traditional single silicon substrate thermal resistance significantly reduces, and chip junction temperature significantly drops, and backing plate bottom micro -groove cooperates with heat conducting adhesive convex strip, and increases contact area, avoids air layer formation, and contact thermal resistance is reduced above significantly, and adapts the external heat dissipation carrier of different flatness.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor power device technology, specifically a high-voltage silicon-based MOSFET structure with heat dissipation function. Background Technology

[0002] High-voltage silicon-based MOSFETs are widely used in new energy inverters, industrial converters, and other fields. During their operation, N... - The drift region and substrate are prone to generating a large amount of heat. Traditional high-voltage silicon-based MOSFETs have the following heat dissipation defects: using a single silicon substrate, direct contact with a metal heat sink can easily lead to high-voltage leakage; the back of the substrate is flat, limiting the contact area with the thermal adhesive / heat sink, with contact thermal resistance accounting for more than 30% of the total thermal resistance, and air layers can easily cause heat dissipation failure; traditional uniformly doped N - Heat in the drift region is transferred to the substrate only in the vertical direction. This path is long and inefficient, and hot spots are easily generated due to current concentration, which affects the reliability and lifespan of the device.

[0003] A single silicon substrate in direct contact with a metal heat sink is prone to leakage due to high voltage; the back of the substrate is flat, with limited contact area with the thermal adhesive / heat sink, resulting in poor heat dissipation; in the traditional drift region, heat is transferred to the substrate only in the vertical direction, which is a long path and inefficient, and is prone to hot spots due to current concentration, affecting the reliability and lifespan of the device. Utility Model Content

[0004] The purpose of this invention is to provide a high-voltage silicon-based MOSFET structure with heat dissipation function to solve the problems mentioned in the background art, such as: a single silicon substrate that is prone to leakage due to high voltage when in direct contact with a metal heat sink; a flat back surface of the substrate with limited contact area with thermal adhesive / heat sink, resulting in poor heat dissipation; and heat transfer from the traditional drift region to the substrate only in the vertical direction, which has a long path, low efficiency, and is prone to hot spots due to current concentration, affecting the reliability and lifespan of the device.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a high-voltage silicon-based MOSFET structure with heat dissipation function, comprising an epitaxial layer, a metal sheet, a gate oxide, and a substrate structure. The metal sheet and the gate oxide are located on top of the epitaxial layer, and the gate oxide is located between the metal sheets. The substrate structure is located at the bottom of the epitaxial layer, and a socket is formed at the bottom of the epitaxial layer. The substrate structure comprises a substrate plate, a thermally conductive adhesive, an insulating and thermally conductive layer, and a metal heat dissipation layer. A thermally conductive pillar is connected to the top of the substrate plate, and the thermally conductive pillar is inserted into the inside of the socket. A microgroove is formed at the bottom of the substrate plate.

[0006] Preferably, a P-well is provided on the top of the epitaxial layer, and a source and a drain are snapped into the inner side of the P-well, with the metal sheet connected to the top of the source and the drain.

[0007] Preferably, the gate oxide is connected to the top of the epitaxial layer, and a polysilicon gate is connected to the top of the gate oxide.

[0008] Preferably, the top of the thermally conductive adhesive is connected to a raised strip, which is engaged with the inside of the microgroove.

[0009] Preferably, the insulating thermally conductive layer is connected to the bottom of the thermally conductive adhesive, and the metal heat dissipation layer is connected to the bottom of the insulating thermally conductive layer.

[0010] The technical effects and advantages of this utility model are as follows: 1. This high-voltage silicon-based MOSFET structure with heat dissipation function uses a three-layer composite structure of "substrate-insulating thermally conductive layer-metal heat dissipation layer". The insulating thermally conductive layer isolates high-voltage leakage current, and the metal heat dissipation layer quickly disperses heat. Compared with the traditional single silicon substrate, the thermal resistance is significantly reduced and the chip junction temperature is significantly reduced. 2. This high-voltage silicon-based MOSFET structure with heat dissipation function has micro-grooves at the bottom of the substrate and thermal conductive adhesive protrusions to increase the contact area, avoid the formation of air layers, and significantly reduce the contact thermal resistance. It is suitable for external heat dissipation carriers with different flatness. 3. This high-voltage silicon-based MOSFET structure with heat dissipation function shortens the heat transfer path with the heat-conducting pillars in the epitaxial layer, significantly reduces the thermal resistance of the drift region, and lowers the hot spot temperature. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the epitaxial layer of this utility model; Figure 3 This is a schematic diagram of the substrate structure of this utility model; Figure 4 This is a schematic diagram of the substrate of this utility model.

[0013] In the figure: 1. Epitaxial layer; 11. P-well; 12. Source and drain; 13. Through-hole; 2. Metal sheet; 3. Gate oxide; 31. Polysilicon gate; 4. Substrate structure; 41. Sheet; 411. Thermal pillar; 412. Microtrench; 42. Thermal adhesive; 421. Raised strip; 43. Insulating and thermally conductive layer; 44. Metal heat dissipation layer. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] This utility model discloses a high-voltage silicon-based MOSFET structure with heat dissipation function, according to the appendix. Figure 1 As shown, it includes an epitaxial layer 1, a metal sheet 2, a gate oxide 3, and a substrate structure 4. The metal sheet 2 and the gate oxide 3 are located on top of the epitaxial layer 1, and the gate oxide 3 is located between the metal sheets 2. The substrate structure 4 is located at the bottom of the epitaxial layer 1.

[0016] According to the appendix Figures 1-2 As shown, further, the epitaxial layer 1 is N - The drift region has a P-well 11 at the top, and a source and drain 12 are snapped into the inner side of the P-well 11. The metal sheet 2 is electrically connected to the top of the source and drain 12. The bottom of the epitaxial layer 1 has uniformly opened insertion holes 13, which are arrayed along the width direction of the epitaxial layer 1 and do not overlap with the source, drain, or gate.

[0017] According to the appendix Figures 1-2 As shown, the gate oxide 3 is further connected to the top of the epitaxial layer 1 and located between adjacent P-wells 11. A polysilicon gate 31 is connected to the top of the gate oxide 3, and the polysilicon gate 31 extends along the length direction of the gate oxide 3.

[0018] According to the appendix Figures 1-4 As shown, the substrate structure 4 further includes a liner 41, a thermally conductive adhesive 42, an insulating and thermally conductive layer 43, and a metal heat dissipation layer 44, with each layer tightly connected from top to bottom. Substrate 41: Employs an N-type silicon substrate, with a vertically connected heat-conducting pillar 411 at the top. The heat-conducting pillar 411 is an N-type silicon substrate. + Heavy doped silicon doping concentration 1×10 19 -5×10 19 cm -3 The diameter is 2-5μm, the height is the same as the thickness of the epitaxial layer 1 (50-100μm), and the spacing is 5-10μm. The heat-conducting pillars 411 correspond one-to-one with the insertion holes 13 and are tightly inserted. The bottom of the liner 41 has microgrooves 412 with a depth of 10-20μm, a width of 5-10μm, a spacing of 15-25μm, and are distributed in an array. Thermally conductive adhesive 42: The thermal conductivity of the silicone-based high thermally conductive adhesive is ≥3W / (m·K). The top is integrally formed with a protrusion 421, which matches and is tightly engaged with the micro-groove 412. The protrusion 421 fills the internal gap of the micro-groove 412. Insulating and thermally conductive layer 43: made of aluminum nitride (AlN) with a thermal conductivity of about 200 W / (m·K) or aluminum oxide with a thermal conductivity of about 30 W / (m·K), with a thickness of 5-15 μm and a breakdown voltage ≥10 kV; Metal heat dissipation layer 44: It is made of oxygen-free copper with a thermal conductivity of about 401 W / (m·K) or aluminum with a thermal conductivity of about 237 W / (m·K), with a thickness of 20-50 μm. The lower surface is roughened by sandblasting to increase the contact area with the external heat sink.

[0019] Working principle: Epitaxial layer N - The heat generated in the drift region is partly dissipated by N + The heat-conducting column 411 directly transfers heat to the liner 41, shortening the vertical heat transfer path; The heat from the liner 41 is efficiently transferred to the insulating and heat-conducting layer 43 through the bottom microgroove 412 and the protrusions 421 of the thermally conductive adhesive 42; While isolating the high voltage, the insulating and heat-conducting layer 43 transfers heat to the metal heat dissipation layer 44, which then rapidly disperses heat to the external heat sink through its roughened surface.

[0020] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0021] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A high-voltage silicon-based MOSFET structure with heat dissipation function, comprising an epitaxial layer (1), a metal sheet (2), a gate oxide (3), and a substrate structure (4), wherein the metal sheet (2) and the gate oxide (3) are located on top of the epitaxial layer (1), and the gate oxide (3) is located between the metal sheets (2), and the substrate structure (4) is located at the bottom of the epitaxial layer (1), characterized in that, The epitaxial layer (1) has an insertion hole (13) at the bottom; the substrate structure (4) includes a liner (41), thermally conductive adhesive (42), an insulating and thermally conductive layer (43), and a metal heat dissipation layer (44). A thermally conductive pillar (411) is connected to the top of the liner (41), and the thermally conductive pillar (411) is inserted into the inside of the insertion hole (13). A microgroove (412) is formed at the bottom of the liner (41).

2. The high-voltage silicon-based MOSFET structure with heat dissipation function according to claim 1, characterized in that, The epitaxial layer (1) has a P-well (11) on top, and a source and a drain (12) are snapped into the inside of the P-well (11). The metal sheet (2) is connected to the top of the source and the drain (12).

3. The high-voltage silicon-based MOSFET structure with heat dissipation function according to claim 1, characterized in that, The gate oxide (3) is connected to the top of the epitaxial layer (1), and a polysilicon gate (31) is connected to the top of the gate oxide (3).

4. The high-voltage silicon-based MOSFET structure with heat dissipation function according to claim 1, characterized in that, The top of the thermally conductive adhesive (42) is connected to a protrusion (421), which is snapped into the inside of the microgroove (412).

5. A high-voltage silicon-based MOSFET structure with heat dissipation function according to claim 1, characterized in that, The insulating thermally conductive layer (43) is connected to the bottom of the thermally conductive adhesive (42), and the metal heat dissipation layer (44) is connected to the bottom of the insulating thermally conductive layer (43).

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