Heterogeneous integrated diode amplitude limiter with local heat dissipation channel and preparation method thereof

Abstract

The invention discloses a heterogeneous integrated diode amplitude limiter with local heat dissipation channels and a preparation method thereof, and relates to the technical field of diode amplitude limiter manufacturing. The invention provides a heterogeneous integrated diode amplitude limiter with local heat dissipation channels, and aims to provide a diode amplitude limiter which is high in heat dissipation capability and high in power resistance level. The semiconductor material with high thermal conductivity is used as the substrate and is heterogeneously integrated with the diode amplitude limiter prepared from the semiconductor material with low thermal conductivity, so that the overall heat dissipation level of the amplitude limiter is improved. Meanwhile, a heat dissipation channel is etched on the substrate right below the diode and is filled with diamond, graphene, boron nitride and other heat dissipation materials with good thermal conductivity, so that the local heat dissipation of the diode is enhanced, and the power tolerance level of the amplitude limiter is further improved. The overall heat dissipation and local heat dissipation of the diode amplitude limiter are enhanced through heterogeneous integration and local heat dissipation channels, the power resistance level of the amplitude limiter is improved, and a rear-end communication system can be better protected.

Description

Technical Field

[0001] The present invention relates to the technical field of diode limiter manufacturing, and in particular to a heterogeneously integrated diode limiter with a local heat dissipation channel. Background Art

[0002] With the rapid development of high-power microwave technology, communications equipment and radar systems face increasingly severe challenges from strong electromagnetic interference. This strong electromagnetic interference enters receiver systems through front-door and back-door coupling paths, generating transient high-voltage fields that can interfere with or even damage sensitive components. To combat this strong electromagnetic interference, diode limiters, as protective devices in communications systems, are widely used at the front end of receiver systems, protecting sensitive components such as low-noise amplifiers and mixers from damage caused by strong electromagnetic interference.

[0003] The higher the limiter's power handling capability, the stronger its protection for communications systems. Existing research indicates that the primary factor limiting the power handling capability of diode limiters is overheating and damage to sensitive components (such as diodes) at high power levels. Therefore, improving the limiter's heat dissipation capability is key to developing high-power microwave diode limiters.

[0004] Currently, commonly used diode limiters utilize Si, GaAs, and GaN substrates. The low thermal conductivity of these substrates limits the limiter's heat dissipation capabilities, resulting in low power handling capabilities. While using high-thermal-conductivity materials such as SiC and diamond as limiter substrates can achieve high power handling capabilities, high manufacturing costs, limited wafer size, and limited microwave performance hinder the large-scale application of diode limiters based on these substrates. Therefore, heterojunction integration of a high-thermal-conductivity substrate with a diode limiter based on a low-thermal-conductivity substrate has become an effective approach to achieving diode limiters with high power handling capabilities, excellent microwave performance, and scalability.

[0005] However, although the existing heterogeneously integrated diode limiter improves the overall heat dissipation performance and power resistance level of the limiter, it does not take into account the local heat dissipation of the high local hotspot diode, resulting in obvious uneven heat distribution in the limiter, which limits the further improvement of the power resistance level of the limiter. Summary of the Invention

[0006] This invention provides a heterogeneously integrated diode limiter with localized heat dissipation channels and a method for fabricating the same. These localized heat dissipation channels enhance the heat dissipation of high localized hotspots within the limiter, thereby reducing uneven heat distribution within the limiter. Furthermore, the use of a heterogeneously integrated high-thermal-conductivity substrate enhances the limiter's overall heat dissipation, ultimately significantly improving the limiter's heat dissipation capacity and power handling capability. This is achieved through the following technologies.

[0007] A heterogeneously integrated diode limiter with a local heat dissipation channel comprises, from top to bottom, a diode limiter body, a first substrate (a low thermal conductivity substrate), a second substrate (a high thermal conductivity substrate), and a ground electrode. The second substrate is provided with a local heat dissipation channel, located directly below the diode of the diode limiter body, and is filled with a heat dissipation material. The second substrate is provided with an electrical interconnection through-hole, which is filled with the same material as the ground electrode. The ground electrode is connected to the output electrode of the diode limiter body via the electrical interconnection through-hole.

[0008] Furthermore, the material of the first substrate includes but is not limited to GaAs, Si or GaN.

[0009] Furthermore, the material of the second substrate includes but is not limited to SiC or diamond.

[0010] Furthermore, the heat dissipation material includes but is not limited to one or more of diamond, graphene, and boron nitride.

[0011] The basic technical concept behind this invention's heterogeneously integrated diode limiter with localized heat dissipation channels is to heterogeneously integrate a diode limiter based on a low-thermal-conductivity substrate (the first substrate) with a high-thermal-conductivity substrate (the second substrate) to improve the limiter's overall heat dissipation. Furthermore, localized heat dissipation channels are etched into the high-thermal-conductivity substrate beneath the diode with the high-localized hotspot and filled with a heat-dissipating material with superior thermal conductivity. This further enhances heat dissipation from the localized hotspot and alleviates the severe overheating of the diode under ultra-high-frequency operating conditions. This design significantly improves both the overall and localized heat dissipation capabilities of the diode limiter, resulting in a diode limiter with a high power handling capability.

[0012] The present invention further provides a method for preparing a heterogeneously integrated diode limiter with a local heat dissipation channel as described in any one of the above, comprising the following steps: preparing the diode limiter body on the front surface of the first substrate, and performing a thinning process on the back surface of the first substrate;

[0013] bonding the front surface of the second substrate to the back surface of the first substrate;

[0014] Etching the local heat dissipation channel and electrical interconnection through-holes on the back side of the second substrate;

[0015] Filling the local heat dissipation channel with the heat dissipation material;

[0016] The ground electrode is deposited inside the electrical interconnection through hole, on the back side of the second substrate and on the surface of the heat dissipation material, and the surface of the ground electrode is planarized.

[0017] Furthermore, after the local heat dissipation channel is filled with the heat dissipation material, excess heat dissipation material on the back surface of the second substrate is removed, and the back surface of the second substrate and the surface of the heat dissipation material are planarized.

[0018] Furthermore, the final thickness of the back side of the first substrate after thinning is 1 / 25-1 / 20 of the initial thickness.

[0019] Furthermore, the back surface of the first substrate and the front surface of the second substrate are bombarded with Ar plasma respectively, and then the front surface of the second substrate is bonded to the back surface of the first substrate.

[0020] Furthermore, the bonding conditions are at 150°C and no higher than 5×10 -5 Pa under vacuum conditions.

[0021] Furthermore, the thickness of the deposited ground electrode is not less than 5 μm.

[0022] Compared with the prior art, the diode limiter of the present invention is beneficial in that:

[0023] 1. Enhanced heat dissipation capability. The heterogeneously integrated diode limiter provided by the present invention utilizes the synergistic heat dissipation effect of the high thermal conductivity substrate and the local heat dissipation channels filled with heat dissipation material. This not only improves the overall heat dissipation capability of the diode limiter, but also alleviates the problem of severe localized heating in the diode during high-power microwave injection, thereby achieving enhanced heat dissipation capability.

[0024] 2. Higher power resistance level. Due to its stronger heat dissipation capability, the diode limiter can withstand higher power microwaves without being damaged. The power capacity is greatly improved, which can better protect the back-end receiver. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of the heterogeneously integrated diode limiter with a local heat dissipation channel provided by the present invention.

[0026] Figure 2 This is a schematic flow chart of the method for preparing the heterogeneously integrated diode limiter with local heat dissipation channels provided in Example 1.

[0027] Figure 3 The figures are the test results of heat dissipation performance of the diode limiters prepared in the examples and comparative examples.

[0028] In the figure: 1. Diode limiter body; 2. First substrate; 3. Second substrate; 4. Ground electrode; 5. Local heat dissipation channel; 6. Heat dissipation material; 7. Electrical interconnection through hole. DETAILED DESCRIPTION

[0029] The technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] In some implementation cases of the present invention, a heterogeneously integrated diode limiter with a local heat dissipation channel is provided, whose structure includes, from top to bottom, a diode limiter body 1, a first substrate 2, a second substrate 3, and a ground electrode 4; a local heat dissipation channel 5 is provided in the second substrate 3, and the local heat dissipation channel 5 is located directly below the diode of the diode limiter body 1, and the local heat dissipation channel 5 is filled with a heat dissipation material 6; an electrical interconnection through-hole 7 is provided in the second substrate 3, and the electrical interconnection through-hole 7 is filled with the same material as the ground electrode 4, and the ground electrode 4 is connected to the output electrode of the diode limiter body 1 through the electrical interconnection through-hole.

[0031] The heterogeneously integrated diode limiter with local heat dissipation channels designed in the present invention is a diode limiter based on a low thermal conductivity substrate (i.e., the first substrate) heterogeneously integrated with a high thermal conductivity substrate (i.e., the second substrate) below the diode limiter. Local heat dissipation channels are etched in the high thermal conductivity substrate directly opposite the high local hotspot diode and filled with a heat dissipation material with better thermal conductivity. Through the synergistic heat dissipation effect of the high thermal conductivity substrate and the heat dissipation material, the heat dissipation capacity of the entire diode limiter and the local hotspot is significantly improved, thereby improving the high power withstand level of the diode limiter.

[0032] Based on the above purposes and effects, optionally, the material of the first substrate includes but is not limited to one or more of GaAs, Si, and GaN.

[0033] Optionally, the material of the second substrate includes but is not limited to SiC and / or diamond.

[0034] Optionally, the heat dissipation material includes but is not limited to one or more of diamond, graphene, and boron nitride.

[0035] In other embodiments of the present invention, a method for preparing a heterogeneously integrated diode limiter with a local heat dissipation channel is provided, the steps comprising:

[0036] preparing the diode limiter body on the front surface of the first substrate and performing a thinning process on the back surface of the first substrate;

[0037] bonding the front surface of the second substrate to the back surface of the first substrate;

[0038] Etching the local heat dissipation channel and electrical interconnection through-holes on the back side of the second substrate;

[0039] Filling the local heat dissipation channel with the heat dissipation material;

[0040] The ground electrode is deposited inside the electrical interconnection through hole, on the back side of the second substrate and on the surface of the heat dissipation material, and the surface of the ground electrode is planarized.

[0041] Optionally, in the above steps, after the local heat dissipation channel is filled with the heat dissipation material, excess heat dissipation material on the back surface of the second substrate is removed, and the back surface of the second substrate and the surface of the heat dissipation material are planarized.

[0042] Optionally, in the above steps, the final thickness of the back side of the first substrate after thinning is 1 / 25-1 / 20 of the initial thickness.

[0043] Optionally, in the above steps, the back surface of the first substrate and the front surface of the second substrate are bombarded with Ar plasma respectively, and then the front surface of the second substrate is bonded to the back surface of the first substrate.

[0044] Optionally, in the above steps, the bonding conditions are 150°C and no more than 5×10 -5 Pa under vacuum conditions.

[0045] Optionally, in the above steps, the thickness of the deposited ground electrode is not less than 5 μm.

[0046] Example 1

[0047] The embodiment provides a heterogeneously integrated diode limiter with a local heat dissipation channel. The diode limiter body is a PIN diode limiter. The first substrate is made of GaAs material, and the second substrate is made of SiC material.

[0048] Specifically prepared by the following method:

[0049] (1) Select a 500 μm thick first substrate (GaAs) and use a standard GaAs semiconductor process (refer to the American RFCMOS process manual) to prepare a 1.5 μm thick PIN diode limiter body on the front of the first substrate. Figure 2 As shown in (1).

[0050] (2) Using chemical mechanical polishing process, the first substrate is thinned to 30 μm. Figure 2 As shown in (2).

[0051] (3) Take a 400 μm thick second substrate (SiC) and activate the front side of the second substrate and the back side of the first substrate with Ar plasma (power 100 W, bombardment time 60 s), bombarding for 60 s each to achieve activation of the surface of the second substrate and the back side of the first substrate.

[0052] The activated first and second substrates were placed in a SUSS MicroTec SB6 bonding machine and bonded at 10 kN pressure, 150°C, and 5×10 -5 Pa vacuum conditions for 5 min. Figure 2 As shown in (3). This realizes heterogeneous integration of the first substrate and the second substrate, as shown in Figure 2 As shown in (3).

[0053] (4) Use Applied Materials’ Endura® DRIE equipment (following the general specification of GB / T 15861-2012) to etch a local heat dissipation channel (corresponding to the diode position) and an electrical interconnection through hole (corresponding to the output electrode position) with a diameter of 80 μm and a depth of 400 μm on the back side of the SiC second substrate. Figure 2 As shown in (4).

[0054] (5) Using microwave plasma chemical vapor deposition (MPCVD) technology (the equipment is the SCMP150 system of Guangdong Zhongyuan Semiconductor Technology Co., Ltd., in accordance with the technical requirements of T / CIET 1178-2025), a diamond film is epitaxially grown inside the local heat dissipation channel and on the back of the second substrate. The thickness of the diamond film is based on at least completely filling the local heat dissipation channel. For example, the thickness of the deposition in the local heat dissipation channel area is at least 410 μm. In this way, the local heat dissipation channel is completely filled with diamond material. The diamond material has excellent heat dissipation performance and a thermal conductivity of not less than 2000 W / (m·K). Figure 2 As shown in (5).

[0055] (6) Using chemical mechanical polishing process, thinning and flattening the diamond material to remove the diamond material on the back of the second substrate, so that the back of the second substrate is exposed again. At this time, the back of the second substrate and the surface of the diamond film in the local heat dissipation channel form a flat and smooth surface, such as Figure 2 As shown in (6).

[0056] (7) Spin-coat a layer of photoresist on the back of the second substrate, expose the photoresist using a double-sided overlay lithography process, and develop to obtain an electrical interconnection through-hole etching window corresponding to the electrical interconnection through-hole. Use a deep reactive ion etching (DRIE) process (using Applied Materials' Endura® DRIE equipment, in accordance with the general specification of GB / T 15861-2012) to etch the SiC material of the second substrate in the etching window until the SiC in the etching window is completely removed. Use plasma to remove the remaining photoresist. Thus, an electrical interconnection through-hole is obtained on the back of the second substrate below the limiter output electrode, as shown in FIG. Figure 2 As shown in (7).

[0057] (8) A gold seed layer is deposited on the back of the second substrate by a sputtering process; a gold film is electroplated on the surface of the second substrate by an electroplating process, and a gold material is filled inside the electrical interconnection through hole. The gold material and the gold film form a whole. The thickness of the gold film formed on the surface of the electrical interconnection through hole is also not less than 5 μm, such as Figure 2 As shown in (8).

[0058] (9) Using chemical mechanical polishing process, the gold film is thinned and flattened to a thickness of 5 μm, and the ground electrode (gold electrode) of the limiter is obtained, such as Figure 2 As shown in (9).

[0059] By the above preparation method, a GaAs-based PIN diode limiter with a heterogeneous integrated SiC substrate and a diamond-filled local heat dissipation channel is prepared.

[0060] Example 2

[0061] The heterogeneously integrated diode limiter with local heat dissipation channels provided in this embodiment is prepared in a method substantially the same as that in Example 1. The difference is that the first substrate in this embodiment is made of Si, the second substrate is made of diamond, and the local heat dissipation channels are filled with graphene material.

[0062] Correspondingly, the method of filling the local heat dissipation channel with graphene material is plasma enhanced chemical vapor deposition.

[0063] By the above preparation method, a Si-based PIN diode limiter with a heterogeneous integrated diamond substrate and a graphene-filled local heat dissipation channel is prepared.

[0064] Example 3

[0065] The heterogeneously integrated diode limiter with local heat dissipation channels provided in this embodiment is prepared in a method substantially the same as that in embodiment 1. The difference is that the first substrate of this embodiment is made of GaN material, and the local heat dissipation channels are filled with boron nitride material.

[0066] Correspondingly, the method of filling the local heat dissipation channel with boron nitride material is plasma enhanced chemical vapor deposition.

[0067] By the above preparation method, a GaN-based PIN diode limiter with a heterogeneous integrated SiC substrate and a local heat dissipation channel filled with boron nitride is prepared.

[0068] Comparative Example 1:

[0069] A PIN diode limiter was prepared by the same method as step (1) of Example 1, and then a 5 μm gold film was obtained on the surface of the first substrate by sputtering, electroplating, and chemical mechanical polishing in the same manner as steps (9) and (10) of Example 1.

[0070] Experimental Example: Study on the Heat Dissipation Performance of the Heterogeneous Integrated Diode Limiter Prepared in the Example and Comparative Example

[0071] 1. Test method

[0072] A GaAs-based diode limiter with a localized diamond heat dissipation channel and a SiC heterojunction substrate, fabricated using the method of Example 1, was selected. A GaAs-based diode limiter without a localized heat dissipation channel, fabricated using a standard GaAs semiconductor process, was selected in Comparative Example 1. To characterize the heat dissipation performance of the two diode limiter substrates, the vertical thermal conductivity of the diode limiter substrates with and without localized heat dissipation channels was measured using a laser thermal conductivity meter (LFA467, Netzsch, Germany).

[0073] 2. Test results

[0074] like Figure 3 As shown in the figure, the vertical thermal conductivity of the GaAs substrate without heat dissipation channels is 140.7 W / (m·K), while that of the GaAs substrate with local diamond heat dissipation channels and SiC heterojunction is 203.6 W / (m·K), which is about 45% higher than that of the substrate without heat dissipation channels. This shows that the high thermal conductivity heterojunction substrate and local heat dissipation channels significantly enhance the heat dissipation capacity of the diode limiter substrate.

[0075] The above specific embodiments describe the implementation of the present invention in detail, but the present invention is not limited to the specific details of the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

Claims

1. A heterogeneously integrated diode limiter with a local heat dissipation channel, characterized in that: From top to bottom, it includes a diode limiter body, a first substrate, a second substrate and a ground electrode; a local heat dissipation channel is provided in the second substrate, the local heat dissipation channel is located directly below the diode of the diode limiter body, and the local heat dissipation channel is filled with heat dissipation material; an electrical interconnection through-hole is provided in the second substrate, and the electrical interconnection through-hole is filled with the same material as the ground electrode, and the ground electrode is connected to the output electrode of the diode limiter body through the electrical interconnection through-hole.

2. The heterogeneously integrated diode limiter with local heat dissipation channel according to claim 1, characterized in that: The first substrate is made of GaAs, Si or GaN.

3. The heterogeneously integrated diode limiter with local heat dissipation channel according to claim 1, characterized in that: The second substrate is made of SiC or diamond.

4. The heterogeneously integrated diode limiter with local heat dissipation channel according to claim 1, characterized in that: The heat dissipation material is one or more of diamond, graphene, and boron nitride.

5. A method for preparing a heterogeneously integrated diode limiter with a local heat dissipation channel according to any one of claims 1 to 4, characterized in that: The following steps are involved: preparing the diode limiter body on the front surface of the first substrate and performing a thinning process on the back surface of the first substrate; bonding the front surface of the second substrate to the back surface of the first substrate; Etching the local heat dissipation channel and electrical interconnection through-holes on the back side of the second substrate; Filling the local heat dissipation channel with the heat dissipation material; The ground electrode is deposited inside the electrical interconnection through hole, on the back side of the second substrate and on the surface of the heat dissipation material, and the surface of the ground electrode is planarized.

6. The preparation method according to claim 5, characterized in that After the local heat dissipation channel is filled with the heat dissipation material, excess heat dissipation material on the back surface of the second substrate is removed, and the back surface of the second substrate and the surface of the heat dissipation material are planarized.

7. The preparation method according to claim 5, characterized in that The final thickness of the back side of the first substrate after thinning is 1 / 25-1 / 20 of the initial thickness.

8. The preparation method according to claim 5, characterized in that The back surface of the first substrate and the front surface of the second substrate are bombarded with Ar plasma respectively, and then the front surface of the second substrate is bonded to the back surface of the first substrate.

9. The preparation method according to claim 5, characterized in that The bonding conditions are 150°C and no more than 5×10 -5 Pa under vacuum conditions.

10. The preparation method according to claim 5, characterized in that The thickness of the deposited ground electrode is not less than 5 μm.

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