Micro-channel heat sink with composite structure and heat dissipation method thereof

Abstract

The application discloses a micro-channel heat dissipation device with a composite structure and a heat dissipation method thereof, which comprises a micro-channel heat sink and a manifold shunt device arranged in sequence at the bottom of a chip; the top of the micro-channel heat sink is provided with a fin array in an open-top form, the top of each fin of the fin array is provided with uniformly spaced inclined grooves; the center of each inclined groove is provided with a rhombic body; the bottom of the micro-channel heat sink is provided with a micro-channel groove bottom inlet and a micro-channel groove bottom outlet, the manifold shunt device is provided with a manifold inlet channel and a manifold outlet channel, the manifold inlet channel is communicated with the micro-channel groove bottom inlet, and the manifold outlet channel is communicated with the micro-channel groove bottom outlet. The application utilizes the manifold inlet channel to divide the fluid, utilizes the inclined grooves and the rhombic body to directly form a secondary flow array at the bottom of the chip for high-efficiency heat exchange, solves the problems of insufficient heat dissipation level of embedded micro-fluid technology and easy damage of the chip caused by direct processing of the micro-channel, and is used for improving the packaging heat dissipation level and working reliability of high-power chips.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of heat transfer enhancement, in particular to a micro-channel heat sink with a composite structure and a heat dissipation method thereof. BACKGROUND

[0002] With the development of semiconductor chip technology, the heat flux density of high-power chips has exceeded 1.5kW / cm 2 Under ultra-high heat flux density, if chip heat dissipation cannot be effectively realized, the chip temperature will be far beyond the standard value, and the chip thermal management problem needs to be solved urgently.

[0003] The existing advanced embedded micro-fluid cooling technology has the advantages of near-junction heat dissipation and low thermal resistance, but direct processing of micro-channels in the chip can easily cause damage to the chip and application risks. Moreover, this technology cannot meet the needs of thick metallization at the bottom of some high-power semiconductor chips and large current and low resistance.

[0004] Large-area high-power chips have obvious problems such as uneven temperature field distribution and thermal stress, which reduce the reliability of the chip. In the conventional embedded micro-fluid technology, the micro-channel heat dissipation fins mostly use long straight fins, which have insufficient heat dissipation strength and uniformity. The use of discontinuous thin fin arrays can improve this problem, but under the requirement of high aspect ratio of the fins, the discontinuous thin fin structure has insufficient strength. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application provides a micro-channel heat sink with a composite structure and a heat dissipation method thereof, which aims to replace the embedded micro-fluid cooling technology without etching and damaging the chip substrate; and comprehensively utilizes the secondary flow and low-thermal-resistance thin boundary layer to directly act on the bottom surface of the chip, thereby further improving the heat dissipation level and uniformity of the embedded micro-fluid.

[0006] The present application discloses a micro-channel heat sink with a composite structure, comprising a micro-channel heat sink and a manifold shunt device arranged in sequence at the bottom of the chip.

[0007] The top of the micro-channel heat sink is provided with a fin array in the form of an open top, and a micro-groove is formed between adjacent fins. The top of each fin of the fin array is provided with a uniformly spaced inclined groove, and the inclined grooves of different fins correspond to form an inclined groove array. The center of each inclined groove is provided with a rhombic body.

[0008] The micro-groove bottom of the micro-channel heat sink is provided with a micro-channel groove bottom inlet and a micro-channel groove bottom outlet, and the manifold shunt device is provided with a manifold inlet channel and a manifold outlet channel. The manifold inlet channel is in communication with the micro-channel groove bottom inlet, and the manifold outlet channel is in communication with the micro-channel groove bottom outlet.

[0009] As a further improvement of the present application, the thickness of the manifold flow splitting device is 1000-1200 μm, N two-end inlet manifold inlet channels are arranged on the manifold flow splitting device, N+1 arrayed manifold outlet channels are arranged on both sides of the outermost manifold inlet channel and between the two adjacent manifold inlet channels, and N≥2.

[0010] As a further improvement of the present application, the two-end inlet of the manifold inlet channel is provided with a bidirectional gradual channel tapering from outside to inside.

[0011] As a further improvement of the present application, the groove width of the manifold inlet channel is 160-450 μm, and changes in a bidirectional linear increasing manner from the middle to the two ends, so as to adjust the uniformity of the inlet flow of each unit rectangular hole of the microchannel heat sink; the groove width of the manifold outlet channel is 450 μm; the manifold inlet channel and the manifold outlet channel are separated by a side wall, and the thickness of the side wall changes in a linear decreasing manner from the middle to the two ends.

[0012] As a further improvement of the present application, the two-end horizontal inlet of the manifold inlet channel is opened at an angle of 130-140°, so as to reduce the resistance of fluid entering the manifold; the groove depth of the manifold inlet channel is 650-700 μm, and the bottom is not connected, and the top is in the form of opening, which is in correspondence with the microchannel groove bottom inlet (rectangular hole) of the upper microchannel heat sink; the manifold outlet channel is completely penetrated from top to bottom, which is in correspondence with the microchannel groove bottom outlet (rectangular hole) of the upper microchannel heat sink.

[0013] As a further improvement of the present application, the thickness of the microchannel heat sink is 500-600 μm, the thickness of the fin and the microgroove width between the adjacent fins are 10-20 μm, and the depth of the microgroove is 350-450 μm; the angle between the inclined groove and the edge of the fin is 45°, and the width of the inclined groove is 50-60 μm; the inclined groove is shallow etched, and the etching depth is 20-30 μm; the long axis direction of the rhombus is consistent with the direction of the inclined groove; the fluid is induced to form a high-density arrayed secondary flow through the inclined groove, and the low thermal resistance thin boundary layer area is expanded by the side wall of the rhombus, so that the above structure can directly and efficiently cool the bottom surface of the chip, and the overall uniformity of the temperature field is improved.

[0014] As a further improvement of the present application, the direction of the inclined groove at the top of the fin is symmetrically arranged along the center of the manifold inlet channel and the manifold outlet channel; the inclined direction of the arrayed inclined groove at the top of the fin is symmetrically distributed along the center of the manifold inlet and outlet, and corresponds to the flow direction of the fluid.

[0015] As a further improvement of the present application, the microchannel is made by jointing the technical means including but not limited to photolithography, plasma dry etching, laser processing, cluster polishing and wafer bonding.

[0016] As a further improvement of the present application, the micro-channel groove bottom inlet and micro-channel groove bottom outlet are rectangular holes, which penetrate to the micro-channel heat sink bottom surface, the width is equivalent to the micro-groove spacing, and the length is equivalent to the manifold inlet and outlet channel width.

[0017] As a further improvement of the present application, the top surface of the manifold shunt device is bonded to the bottom surface of the micro-channel heat sink, the top surface of the inclined groove and the rhombus is bonded to the bottom surface of the chip, and the bonding method includes one of direct bonding, gold-tin wafer bonding, gold-silicon wafer bonding and gold-indium wafer bonding; the chip substrate can be in a thinned form to minimize the chip thermal resistance.

[0018] As a further improvement of the present application, the material of the micro-channel heat sink and the manifold shunt device includes one or a combination of high thermal conductivity materials such as silicon, aluminum nitride, silicon carbide and diamond, and the cooling fluid flowing in the micro-channel heat sink and the manifold shunt device includes one of deionized water, liquid nitrogen, liquid helium and liquid metal.

[0019] The application discloses a heat dissipation method of a micro-channel heat dissipation device based on a composite structure.

[0020] Step 1, the cooling fluid enters the channel horizontally through the two-end inlet of the manifold inlet channel, and then the fluid rises from the micro-channel groove bottom inlet array of the micro-channel heat sink and vertically impacts the bottom surface of the heat source chip in the form of a jet array along the fin wall surface;

[0021] Step 2, the fluid is shunted from the center to both sides along the chip bottom surface and the fin side wall, and flows along the inclined groove and the rhombus on the top of the fin to form a high-density secondary flow array and an ultrathin boundary layer respectively; the secondary flow array has high field synergy, and the ultrathin boundary layer has extremely low thermal resistance, and the combination of the two can directly strengthen the heat exchange at the bottom of the chip;

[0022] Step 3, the fluid meets at the center of the area opposite to the micro-channel groove bottom outlet, turns back downward, and reaches the manifold outlet channel along the micro-channel groove bottom outlet, and then flows vertically downward to complete a convection heat exchange cycle.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] The application opens high-density high-aspect-ratio fins on the micro-channel heat sink, and the top of the fin is bonded to the bottom of the heat source chip, thereby improving the existing advanced embedded micro-fluid technology; the method avoids the damage and application hazards caused by directly processing micro-channels on the chip substrate, and still has the high-efficiency heat exchange performance of the embedded micro-fluid technology with low heat dissipation; and after the chip substrate is thinned, the chip substrate can be thickly metallized to meet the needs of high-power chips, large current and low thermal resistance.

[0025] The bidirectional gradual change in width of the manifold inlet channel of the present invention has the effect of evenly distributing the fluid and reduces pump power loss.

[0026] The cooling fluid of the present invention forms a jet array through the bottom holes of the microchannel heat sink, and the jets directly impact the bottom surface of the heat source chip, thereby achieving a high level of field synergistic heat exchange.

[0027] The top of the fin of the present invention is provided with a high-density micro shallow inclined groove array, and rhombus bodies are arranged at intervals; thereby inducing the formation of a high-density secondary flow array and an ultra-thin boundary layer, which directly acts on the bottom surface of the heat source chip, not only enhancing the field synergy of convective heat transfer and improving the uniformity of the temperature field; at the same time, the shallow groove setting avoids the problem of insufficient strength of the slender tooth structure.

[0028] The cooling fluid of the present invention enters through the tapered holes at both ends of the manifold inlet channel, which reduces fluid resistance and reduces pump power loss.

[0029] The cooling fluid of the present invention flows out through the manifold outlet channels spaced apart between the inlet channels and is led out nearby, thereby avoiding the retention of the convective heat transfer heating fluid, enhancing the heat transfer effect, improving the temperature field uniformity, and reducing pump power loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 An exploded view of the microchannel heat dissipation device with a composite structure disclosed in the present invention;

[0031] Figure 2 for Figure 1 A partial enlarged schematic diagram of the microchannel heat sink;

[0032] Figure 3 for Figure 1 Schematic diagram of the entry and exit rectangular slots at the bottom of the fins of the microchannel heat sink;

[0033] Figure 4 for Figure 1 Schematic diagram of the inclined grooves and rhombuses on the fin tops of the microchannel heat sink;

[0034] Figure 5 for Figure 1 Schematic diagram of the structure of the middle manifold diversion device;

[0035] Figure 6 A schematic diagram of the fluid flow direction of the microchannel heat dissipation device with a composite structure disclosed in the present invention;

[0036] Figure 7 This is the temperature field distribution cloud diagram of the embedded microfluidic straight microchannel heat dissipation disclosed in the present invention, taking the symmetrical Figure 1 / 2;

[0037] Figure 8The micro-channel heat dissipation temperature field distribution cloud chart disclosed by the present application is symmetrical Figure 1 / 2.

[0038] Reference signs:

[0039] 1. Micro-channel heat sink; 101. Fin array; 102. Micro-channel groove bottom inlet; 103. Micro-channel groove bottom outlet; 104. Rhombus; 105. Inclined groove; 2. Manifold shunt device; 201. Manifold inlet channel; 202. Manifold outlet channel; 203. Gradual change channel; 3. Chip. DETAILED DESCRIPTION

[0040] In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure clearer, the following will be combined with the drawings of the embodiments of the present application to make the specific embodiments of the embodiments of the present application clearer and more complete. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0041] In the description of the embodiments of the present disclosure, it should be noted that the orientations or positional relationships indicated by the terms "upper", "lower", "center", "length", "width", "thickness", "vertical", "horizontal", "top surface", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the device or component referred to must have a particular orientation, therefore it cannot be understood as a limitation to the present application.

[0042] In the embodiments of the present disclosure, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is horizontally higher than the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is lower than that of the second feature.

[0043] The present application will be further described in detail below in combination with the drawings:

[0044] As Figures 1 to 6As shown, the present application provides a composite structure micro-channel heat dissipation device, which comprises a micro-channel heat sink 1 and a manifold shunt device 2 arranged in sequence at the bottom of a chip 3, and the micro-channel heat sink 1, the manifold shunt device 2 and the chip 3 are bonded into one body, the top of the micro-channel heat sink 1 is provided with a fin array 101 in the form of open top, and micro-channels are formed between adjacent fins; the top of each fin of the fin array 101 is provided with uniformly spaced inclined grooves 105, and the inclined grooves 105 of different fins correspond to form an inclined groove array; the center of each inclined groove 105 is provided with a rhombus 104; the bottom of the micro-channel of the two ends of the micro-channel heat sink 1 is provided with a micro-channel groove bottom inlet 102 and a micro-channel groove bottom outlet 103, the manifold shunt device 2 is provided with a manifold inlet channel 201 and a manifold outlet channel 202, the manifold inlet channel 201 is communicated with the micro-channel groove bottom inlet 102, and the manifold outlet channel 202 is communicated with the micro-channel groove bottom outlet 102; preferably, the manifold shunt device 2 is provided with N manifold inlet channels 201 with inflow at both ends, and N+1 manifold outlet channels 202 are arranged in an array on the both sides of the outermost manifold inlet channel and between the adjacent two manifold inlet channels, N≥2; the fin direction of the micro-channel heat sink 1 is perpendicular to the channel direction of the manifold shunt device 2, the micro-channel groove bottom inlet 102 is rectangular and only communicated with the manifold inlet channel 201, and the micro-channel groove bottom outlet 103 is rectangular and only communicated with the manifold outlet channel 202.

[0045] As shown, Figures 2 to 4 As shown, the micro-channel heat sink 1 has high-density high-aspect-ratio fins 101, and the micro-channel groove bottom inlet 102 and the micro-channel groove bottom outlet 103 are arranged at the bottom of the inter-fin groove, both of which are rectangular holes; the width of the micro-channel groove bottom inlet 102 and the micro-channel groove bottom outlet 103 is equivalent to the fin spacing, and the length is equivalent to the width of the manifold inlet and outlet; the thickness of the micro-channel heat sink 1 is 500μm-600μm, the thickness of the fin and the width of the micro-channel between adjacent fins are 10μm-20μm, and the depth of the micro-channel is 350μm-450μm; the inclined groove 105 forms a 45° angle with the edge of the fin, and the width is 50μm-60μm, the inclined groove is shallow etching and the etching depth is 20μm-30μm, and the long axis direction of the rhombus 104 is consistent with the direction of the inclined groove; the fluid is induced to form a high-density array secondary flow through the inclined groove, and the low-thermal-resistance thin boundary layer area is expanded by the rhombus side wall, the above structure can directly and efficiently cool the bottom surface of the chip, and the overall uniformity of the temperature field is improved. Further, the inclined groove direction of the fin top is arranged symmetrically along the center of the manifold inlet channel and the manifold outlet channel; that is, the inclined groove array of the fin top is distributed symmetrically along the center of the manifold inlet and outlet, corresponding to the fluid flow direction.

[0046] As shown, Figure 5As shown, the two ends of the manifold inlet channel 201 are provided with bidirectional tapering channels 203 tapering from outside to inside, the groove width of the manifold inlet channel is 160-450 μm, and the groove width changes in a bidirectional linear increasing manner from the middle to the two ends, so as to adjust the uniformity of the inlet flow of each unit rectangular hole of the microchannel heat sink; the groove width of the manifold outlet channel is 450 μm; the manifold inlet channel 201 and the manifold outlet channel 202 are separated by a side wall, the thickness of the side wall changes in a linear decreasing manner from the middle to the two ends, and the thickness of the side wall is 150-300 μm. Further, the horizontal inlet at the two ends of the manifold inlet channel is opened at an angle of 130-140°, so as to reduce the resistance of the fluid entering the manifold; the groove depth of the manifold inlet channel is 650-700 μm, and the bottom is not connected, and the top is in the form of an opening, which is connected with the microchannel groove bottom inlet (rectangular hole) of the upper microchannel heat sink; the manifold outlet channel is completely connected from top to bottom, and is connected with the microchannel groove bottom outlet (rectangular hole) of the upper microchannel heat sink.

[0047] The heat dissipation method of the present application comprises:

[0048] The cooling fluid working substance flows into the manifold shunt device through the two end inlets of the manifold, and the cooling fluid working substance is incident upward through the microchannel bottom rectangular hole in the manifold inlet channel, impacts the bottom surface of the heat source chip 3 along the fin wall surface, and then flows out to the two sides, passes through the microgroove wall surface of the fin 101, and bypasses the array of inclined grooves 105 and the array of rhombic bodies 104 at the top of the fin 101. The array of inclined grooves 105 can induce a plurality of micro secondary flow arrays, and the central rhombic body 104 can increase the thin boundary layer region near the heat source chip 3 region, and strengthen heat exchange. Then, the convective heat transfer fluid working substance flows to the two sides through a plurality of groups of inclined groove arrays, and then converges with the adjacent channel flow, and is guided out vertically downward along the manifold outlet channel.

[0049] When the heat flux density of the power chip 3 is 1500 W / cm 2 , the flow rate of the deionized water in the inlet channel of the composite microchannel heat dissipation device is 1 m / s, and the existing embedded microfluidic technology and the embodiment of the present application are used for simulation comparison. The temperature field distribution cloud diagram of the chip surface obtained by fluid simulation software simulation analysis is as shown in Figure 7 , Figure 8 . The specific numerical values of the maximum temperature and the temperature difference are shown in Table 1.

[0050] Table 1

[0051]

[0052] As can be seen from the data comparison in Table 1, compared with the embedded microfluidic cooling technology, the maximum temperature of the embodiment of the present application is reduced by 9K, and the temperature difference is reduced by 38.9%.

[0053] The application is used for high-power chip thermal management, has the advantages of no damage to the chip, higher heat exchange level, better temperature uniformity, lower thermal stress and the like.

[0054] The above merely describes the preferred embodiments of the present application but is not intended to limit the present application. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A microchannel heat spreader of a composite structure, characterized by, The micro-channel heat sink and the manifold shunt device are sequentially arranged at the bottom of the chip; The top of the micro-channel heat sink is provided with a fin array in the form of an open top, and micro-slots are formed between adjacent fins; the top of each fin of the fin array is provided with uniformly spaced inclined grooves, and the inclined grooves of different fins correspond to form an inclined groove array; the center of each inclined groove is provided with a rhombus; The bottom of the micro-channel heat sink is provided with a micro-channel groove bottom inlet and a micro-channel groove bottom outlet, the manifold shunt device is provided with a manifold inlet channel and a manifold outlet channel, the manifold inlet channel is in communication with the micro-channel groove bottom inlet, and the manifold outlet channel is in communication with the micro-channel groove bottom outlet.

2. The microchannel heat spreader of claim 1, wherein, The thickness of the manifold shunt device is 1000μm-1200μm, the manifold shunt device is provided with N manifold inlet channels with inflow at both ends, and N+1 array distributed manifold outlet channels are arranged at both sides of the outermost manifold inlet channel and between adjacent two manifold inlet channels, N≥2.

3. The microchannel heat spreader of claim 1 or 2, wherein the composite structure is a metal matrix composite. The both-end inlet of the manifold inlet channel is provided with a bidirectional gradual change channel which gradually shrinks from outside to inside.

4. The microchannel heat spreader of claim 3, wherein the composite structure is formed by a process comprising: The groove width of the manifold inlet channel is 160μm-450μm, which changes in a bidirectional linear increasing rule from the middle to both ends, and the groove width of the manifold outlet channel is 450μm; the manifold inlet channel and the manifold outlet channel are separated by a side wall, and the thickness of the side wall is 150μm-300μm, which changes in a linear decreasing rule from the middle to both ends.

5. The microchannel heat spreader of claim 3, wherein the microchannel heat spreader is a composite structure. The both-end horizontal inlet of the manifold inlet channel is an opening with an angle of 130°-140°, the groove depth of the manifold inlet channel is 650μm-700μm and the bottom is not communicated, and it is in correspondence with the micro-channel groove bottom inlet of the upper micro-channel heat sink; the manifold outlet channel is completely penetrated from top to bottom, and it is in correspondence with the micro-channel groove bottom outlet of the upper micro-channel heat sink.

6. The microchannel heat spreader of claim 1, wherein the composite structure is formed by a process comprising: The thickness of the micro-channel heat sink is 500μm-600μm, the thickness of the fin and the width of the micro-slot between adjacent fins are 10μm-20μm, and the depth of the micro-slot is 350μm-450μm; the inclined groove and the fin edge form an angle of 45°, and the width is 50μm-60μm; the inclined groove is shallow etching, and the etching depth is 20μm-30μm; the long axis direction of the rhombus is consistent with the direction of the inclined groove.

7. The microchannel heat spreader of claim 6, wherein the composite structure is formed by a process comprising: The inclined groove direction of the fin top is symmetrically arranged along the center of the manifold inlet channel and the manifold outlet channel.

8. The microchannel heat spreader of claim 1, wherein the composite structure is formed by a process comprising: providing a first layer of a first material; providing a second layer of a second material; and bonding the first layer to the second layer. The top surface of the manifold shunt device is bonded and packaged with the bottom surface of the micro-channel heat sink, the top surface of the inclined groove and the rhombus is bonded and packaged with the bottom surface of the chip, and the bonding mode includes one of direct bonding, gold-tin wafer bonding, gold-silicon wafer bonding and gold-indium wafer bonding.

9. The microchannel heat spreader of claim 1, wherein, The material of the micro-channel heat sink and the manifold shunt device includes one or a combination of silicon, aluminum nitride, silicon carbide and diamond, and the cooling fluid flowing in the micro-channel heat sink and the manifold shunt device includes one of deionized water, liquid nitrogen, liquid helium and liquid metal.

10. A heat dissipation method using a microchannel heat dissipation device based on the composite structure according to any one of claims 1 to 9, characterized by, It comprises: Step 1, the cooling fluid enters the microchannel heat sink horizontally through the manifold inlet channel, and then rises from the microchannel groove bottom inlet array of the microchannel heat sink and vertically impacts the bottom surface of the chip in the form of a jet array; Step 2, the fluid is divided from the center to both sides along the chip bottom surface and the fin side wall, and flows along the fin top inclined groove and the rhombus, respectively forming a high-density secondary flow array and an ultrathin boundary layer; Step 3, the fluid meets at the center of the area opposite the microchannel groove bottom outlet, turns down, and reaches the manifold outlet channel along the microchannel groove bottom outlet, and then flows vertically downward to complete a convection heat exchange cycle.

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