Micro-channel heat dissipation device of composite structure and heat dissipation method of micro-channel heat dissipation device

Abstract

The invention discloses a micro-channel heat dissipation device with a composite structure and a heat dissipation method thereof. The micro-channel heat dissipation device comprises a micro-channel heat sink and a manifold shunting device which are sequentially arranged at the bottom of a chip, the top of the micro-channel heat sink is provided with a fin array with an open top, and the top of each fin of the fin array is provided with chutes which are uniformly spaced; a rhombus body is arranged in the center of each chute; a micro-channel groove bottom inlet and a micro-channel groove bottom outlet are formed in the bottom of a micro-channel of the micro-channel heat sink, a manifold inlet channel and a manifold outlet channel are arranged on the manifold shunting device, 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. Fluid is equally divided through the manifold inlet channel, a secondary flow array is directly formed at the bottom of the chip through the inclined grooves and the rhombic bodies for efficient heat exchange, the problems that the heat dissipation level of the embedded microfluid technology is insufficient, and the chip is prone to being damaged when the microgrooves are directly machined are solved, and the packaging heat dissipation level and the working reliability of the high-power chip are improved.

Description

Technical Field

[0001] The invention relates to the technical field of enhanced heat exchange, and in particular to a microchannel heat dissipation device with a composite structure and a heat dissipation method thereof. Background Art

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

[0003] Existing advanced embedded microfluidic cooling technology has the advantages of near-junction heat dissipation and low thermal resistance, but directly processing microchannels in the chip can easily cause damage to the chip and application risks. Moreover, this technology cannot meet the requirements of thick metallization at the bottom of some high-power semiconductor chips, high current and low resistance.

[0004] Large-area high-power chips have many problems such as uneven temperature field distribution and thermal stress, which reduce chip reliability. In conventional embedded microfluidic technology, most microchannel heat sinks use long straight fins, which have insufficient heat dissipation strength and temperature uniformity. The use of intermittent thin fin arrays can improve this problem, but under the high aspect ratio requirement of the fins, the intermittent thin fin structure is not strong enough. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a microchannel heat dissipation device with a composite structure and a heat dissipation method thereof, which aims to replace the embedded microfluidic cooling technology without etching and damaging the chip substrate; comprehensively utilize secondary flow, and a low thermal resistance thin boundary layer directly acts on the bottom surface of the chip, further improving the heat dissipation level and temperature uniformity of the embedded microfluidic.

[0006] The present invention discloses a microchannel heat dissipation device of composite structure, comprising a microchannel heat sink and a manifold flow dividing device arranged in sequence at the bottom of a chip;

[0007] The top of the microchannel heat sink is provided with a fin array in the form of an open top, and micro grooves are formed between adjacent fins; the top of each fin of the fin array is provided with evenly spaced oblique grooves, and the oblique grooves of different fins correspond to each other to form an oblique groove array; a rhombus is provided at the center of each oblique groove;

[0008] The microchannel bottom of the microchannel heat sink is provided with a microchannel bottom inlet and a microchannel bottom outlet, and the manifold diversion device is provided with a manifold inlet channel and a manifold outlet channel, the manifold inlet channel is connected to the microchannel bottom inlet, and the manifold outlet channel is connected to the microchannel bottom outlet.

[0009] As a further improvement of the present invention, the thickness of the manifold shunt device is 1000 μm to 1200 μm. The manifold shunt device is provided with N manifold inlet channels with two ends for inflow. A total of N + 1 array-distributed manifold outlet channels arranged at intervals are provided on both sides of the outermost manifold inlet channel and between two adjacent manifold inlet channels, where N ≥ 2.

[0010] As a further improvement of the present invention, both ends of the manifold inlet channel are provided with a two-way tapered channel that tapers from the outside to the inside.

[0011] As a further improvement of the present invention, the groove width of the manifold inlet channel is 160 μm to 450 μm, and it changes according to the law of two-way linear increase from the middle to both ends, so as to adjust the uniformity of the inlet flow of each rectangular hole of the microchannel heat sink; the groove width of the manifold outlet channel is 450 μm; there is a side wall between the manifold inlet channel and the manifold outlet channel, and the thickness of the side wall is 150 μm to 300 μm, and it changes according to the law of linear decrease from the middle to both ends.

[0012] As a further improvement of the present invention, the two horizontal inlets of the manifold inlet channel are opened at an angle of 130° to 140°, reducing the resistance of the fluid entering the manifold; the groove depth of the manifold inlet channel is 650 μm to 700 μm and the bottom is not connected, and the upper part is in an open form, which corresponds to and communicates with the microchannel bottom inlet (rectangular hole) of the upper microchannel heat sink; the manifold outlet channel is completely through up and down, and it corresponds to and communicates with the microchannel bottom outlet (rectangular hole) of the upper microchannel heat sink.

[0013] As a further improvement of the present invention, the thickness of the microchannel heat sink is 500 μm to 600 μm, the thickness of the fin and the width of the microgroove between adjacent fins are 10 μm to 20 μm, and the depth of the microgroove is 350 μm to 450 μm; the inclined groove forms a 45° angle with the fin edge, and the width is 50 μm to 60 μm. The inclined groove is shallowly etched and the etching depth is 20 μm to 30 μm. The long axis direction of the rhomboid is the same as the direction of the inclined groove; the fluid is induced by the inclined groove to form a high-density array of secondary flows, and the low-resistance thin boundary layer region is expanded by means of the side wall of the rhomboid. The above structure can directly and efficiently cool the bottom surface of the chip and also improve the overall uniformity of the temperature field.

[0014] As a further improvement of the present invention, the directions of the inclined grooves at the top of the fins are arranged symmetrically about the centers of the manifold inlet channels and the manifold outlet channels; the inclined directions of the inclined groove arrays at the top of the fins are symmetrically distributed on the left and right about the centers of the manifold inlet and outlet, corresponding to the fluid flow direction.

[0015] As a further improvement of the present invention, the microchannel is made by combining 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 invention, the inlet of the bottom of the microchannel and the outlet of the bottom of the microchannel are rectangular holes, which penetrate to the bottom surface of the microchannel heat sink, and the width is equivalent to the microgroove pitch, and the length corresponds to the width of the manifold inlet and outlet channels.

[0017] As a further improvement of the present invention, the top surface of the manifold shunt device is bonded and encapsulated with the bottom surface of the microchannel heat sink, and the top surfaces of the inclined grooves and the rhombohedrons are bonded and encapsulated with the bottom surface of the chip. The bonding methods include one of direct bonding, Au—Sn wafer bonding, Au—Si wafer bonding, and Au—In 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 invention, the materials of the microchannel heat sink and the manifold shunt device include 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 microchannel heat sink and the manifold shunt device includes one of fluids such as deionized water, liquid nitrogen, liquid helium, and liquid metal.

[0019] The present invention discloses a heat dissipation method for a microchannel heat dissipation device based on a composite structure, including:

[0020] Step 1: The cooling fluid horizontally enters the channel through the two ends of the manifold inlet channel, and then the fluid rises from the inlet array of the bottom of the microchannel of the microchannel 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 bottom surface of the chip and the side wall of the fin, and flows around the inclined grooves and the rhombohedrons at the top of the fin, respectively forming a high-density secondary flow array and an ultra-thin boundary layer; the secondary flow array has high field synergy, and the ultra-thin boundary layer has extremely low thermal resistance. The combination of the two can directly enhance heat transfer at the bottom of the chip;

[0022] Step 3: The fluid meets at the center of the area of the outlet of the bottom of the microchannel, turns back downward, and reaches the manifold outlet channel along the outlet of the bottom of the microchannel, and then flows out vertically downward to complete a convective heat transfer cycle.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The present invention opens high-density and high aspect ratio fins on the microchannel heat sink, and the top of the fin is bonded to the bottom of the heat source chip as a whole, so as to improve the existing advanced embedded microfluidic technology; this method avoids the damage and application hazards caused by directly processing microchannels on the chip substrate, and does not lose the high-efficiency heat transfer performance of the near-junction heat dissipation with low thermal resistance of the embedded microfluidic technology; moreover, after the chip substrate is thinned, it can be thick metalized to meet the requirements of high-power chips for large current and low thermal resistance.

[0025] The bidirectional gradient form of the width of the manifold inlet channel for the cooling fluid of the present invention has the effect of evenly distributing the fluid while reducing the 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 directly jets and impacts the bottom surface of the heat source chip, having a high level of heat transfer cooperation in the height field.

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

[0028] The tapered hole inlet form at both ends of the manifold inlet channel for the cooling fluid of the present invention reduces the fluid resistance and the pump power loss.

[0029] The cooling fluid of the present invention flows out through the manifold outlet channels distributed at intervals between the inlet channels, and the form of discharging nearby avoids the retention of the fluid heated by convective heat transfer, enhances the heat transfer effect, improves the temperature field uniformity, and reduces the pump power loss. Brief Description of the Drawings

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

[0031] Figure 2 is Figure 1 a partially enlarged schematic view of the microchannel heat sink in

[0032] Figure 3 is Figure 1 a schematic view of the position of the rectangular inlet and outlet holes at the bottom of the fin of the microchannel heat sink in

[0033] Figure 4 is Figure 1 a schematic view of the inclined grooves and rhomboids on the top of the fin of the microchannel heat sink in

[0034] Figure 5 is Figure 1 a schematic view of the structure of the manifold shunt device in

[0035] Figure 6 is a schematic view of the fluid flow direction of the microchannel heat dissipation device with a composite structure disclosed by the present invention;

[0036] Figure 7 is the temperature field distribution cloud map of the embedded microfluidic straight microchannel heat dissipation of the present invention, taking symmetry Figure 1 / 2;

[0037] Figure 8This is the contour map of the microchannel heat dissipation temperature field disclosed by the present invention. Take the symmetry Figure 1 / 2.

[0038] Reference numerals:

[0039] 1. Microchannel heat sink; 101. Fin array; 102. Microchannel bottom inlet; 103. Microchannel bottom outlet; 104. Rhombohedron; 105. Inclined groove; 2. Manifold shunt device; 201. Manifold inlet channel; 202. Manifold outlet channel; 203. Gradient channel; 3. Chip. Specific embodiments

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the specific embodiments in the embodiments of the present invention will be described more clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0041] In the description of the embodiments of the present disclosure, it should be noted that the orientation or positional relationships indicated by the terms "upper", "lower", "center", "length", "width", "thickness", "vertical", "horizontal", "top surface", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, and thus should not be construed as a limitation of the present invention.

[0042] In the embodiments of the present disclosure, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature may 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 being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is horizontally lower than the second feature.

[0043] The present invention will be further described in detail below with reference to the accompanying drawings:

[0044] As Figures 1 to 6As shown in the figure, the present invention provides a microchannel heat dissipation device with a composite structure, which includes a microchannel heat sink 1 and a manifold shunt device 2 sequentially arranged at the bottom of a chip 3. The microchannel heat sink 1, the manifold shunt device 2 and the chip 3 are bonded into one body. The top of the microchannel heat sink 1 is provided with a fin array 101 in an open-top form, and microgrooves are formed between adjacent fins; each fin of the fin array 101 is provided with evenly spaced inclined grooves 105 at the top, and the inclined grooves 105 of different fins correspond to each other to form an inclined groove array; a rhomboid 104 is provided at the center of each inclined groove 105; microchannel bottom inlets 102 and microchannel bottom outlets 103 are provided at the bottoms of the microgrooves at both ends of the microchannel heat sink 1. 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 microchannel bottom inlet 102, and the manifold outlet channel 202 is communicated with the microchannel bottom outlet 102; preferably, the manifold shunt device 2 is provided with N manifold inlet channels 201 with two ends inflowing, and a total of N + 1 array-distributed manifold outlet channels 202 arranged at intervals are provided on both sides of the outermost manifold inlet channel and between adjacent two manifold inlet channels, N≥2; the fin direction of the microchannel heat sink 1 is perpendicular to the channel direction of the manifold shunt device 2. The microchannel bottom inlet 102 is rectangular and is only communicated with the manifold inlet channel 201, and the microchannel bottom outlet 103 is rectangular and is only communicated with the manifold outlet channel 202.

[0045] As Figures 2 to 4 shown, the microchannel heat sink 1 has high-density and high aspect ratio fins 101. Microchannel bottom inlets 102 and microchannel bottom outlets 103 are opened at the bottom of the grooves between the fins, and both are rectangular holes; the widths of the microchannel bottom inlets 102 and the microchannel bottom outlets 103 are equivalent to the fin spacing, and the lengths correspond to the widths of the manifold inlets and outlets; the thickness of the microchannel heat sink 1 is 500μm - 600μm, the thickness of the fins and the width of the microgrooves between adjacent fins are 10μm - 20μm, and the depth of the microgrooves is 350μm - 450μm; the inclined groove 105 forms a 45° angle with the fin edge, the width is 50μm - 60μm, the inclined groove is a shallow etching and the etching depth is 20μm - 30μm, and the major axis direction of the rhomboid 104 is consistent with the direction of the inclined groove; the fluid is induced by the inclined groove to form a high-density array secondary flow, and the low thermal resistance thin boundary layer region is expanded by means of the side wall of the rhomboid. The above structure can directly and efficiently cool the bottom surface of the chip and also improve the overall uniformity of the temperature field. Further, the inclined groove directions at the top of the fins are arranged symmetrically about the centers of the manifold inlet channel and the manifold outlet channel; that is, the inclination directions of the inclined groove array at the top of the fins are symmetrically distributed left and right about the centers of the manifold inlet and outlet, corresponding to the fluid flow direction.

[0046] As Figure 5As shown in the figure, both ends of the manifold inlet channel 201 are provided with a two-way tapered channel 203 that tapers from the outside to the inside. The groove width of the manifold inlet channel is 160 μm to 450 μm, and it changes according to the law of two-way linear increase from the middle to both ends, so as to adjust the uniformity of the inlet flow rate of each rectangular hole in the microchannel heat sink. The groove width of the manifold outlet channel is 450 μm. There is a side wall between the manifold inlet channel 201 and the manifold outlet channel 202, and the thickness of the side wall is 150 μm to 300 μm, which changes according to the law of linear decrease from the middle to both ends. Further, the horizontal inlets at both ends of the manifold inlet channel are open at an angle of 130° to 140°, reducing the resistance of the fluid entering the manifold. The groove depth of the manifold inlet channel is 650 μm to 700 μm and the bottom is not connected, and it is in an open form on the top, and it corresponds to and communicates with the microchannel groove bottom inlet (rectangular hole) of the upper microchannel heat sink. The manifold outlet channel is completely through from top to bottom, and it corresponds to and communicates with the microchannel groove bottom outlet (rectangular hole) of the upper microchannel heat sink.

[0047] The heat dissipation method of the present invention includes:

[0048] The cooling fluid working medium flows into the manifold shunt device oppositely through the inlets at both ends of the manifold; the cooling fluid working medium enters upward through the rectangular holes at the bottom of the microchannels 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 both sides, passing through the microgroove wall surface of the fin 101, and bypassing between the inclined groove 105 array and the rhomboid 104 array at the top of the fin 101. The inclined groove 105 array can induce the generation of many micro secondary flow arrays, and the central rhomboid 104 can increase the thin boundary layer region in the area near the heat source chip 3, strengthening heat transfer. Then, the convective heat transfer fluid working medium flows to both sides through multiple groups of inclined groove arrays, and then intersects oppositely with the incoming flow from adjacent channels, and is vertically downward along the manifold outlet channel through the outlet.

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

[0050] Table 1

[0051]

[0052] It can be seen from the data comparison in Table 1 that compared with the embedded microfluidic cooling technology scheme, in the implementation scheme of the present disclosure, the highest temperature is reduced by 9 K, and the temperature difference is reduced by 38.9%.

[0053] The present invention is used for high-power chip thermal management, and has the advantages of not damaging the chip, higher heat transfer level, better temperature uniformity, lower thermal stress, etc. The present invention can also be further extended to the packaging heat dissipation application of high-power large-area single chips at the wafer level.

[0054] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A microchannel heat dissipation device with a composite structure, characterized in that, It includes a microchannel heat sink and a manifold shunt device sequentially arranged at the bottom of the chip; The top of the microchannel heat sink is provided with a fin array in an open-top form, and microgrooves 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 are opposite to form an inclined groove array; a rhombohedron is provided at the center of each inclined groove; The bottom of the microgroove of the microchannel heat sink is provided with a microchannel bottom inlet and a microchannel 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 microchannel bottom inlet, and the manifold outlet channel is communicated with the microchannel bottom outlet.

2. The microchannel heat dissipation device with a composite structure according to claim 1, characterized in that 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 a total of N + 1 array-distributed manifold outlet channels arranged at intervals are provided on both sides of the outermost manifold inlet channel and between adjacent two manifold inlet channels, N≥2.

3. The microchannel heat dissipation device with a composite structure according to claim 1 or 2, characterized in that, Both ends of the manifold inlet channel are provided with a bidirectional tapered channel that tapers from the outside to the inside.

4. The microchannel heat dissipation device with the composite structure according to claim 3, characterized in that, The groove width of the manifold inlet channel is 160μm - 450μm, and it changes according to the law of bidirectional linear increase from the middle to both ends. The groove width of the manifold outlet channel is 450μm; there is a side wall between the manifold inlet channel and the manifold outlet channel, and the thickness of the side wall is 150μm - 300μm, and it changes according to the law of linear decrease from the middle to both ends.

5. The microchannel heat dissipation device with a composite structure according to claim 3, characterized in that, Both horizontal inlets at both ends of the manifold inlet channel are open at an angle of 130° - 140°, the groove depth of the manifold inlet channel is 650μm - 700μm and the bottom is not through, and it is correspondingly communicated with the microchannel bottom inlet of the upper microchannel heat sink; the manifold outlet channel is completely through up and down, and it is correspondingly communicated with the microchannel bottom outlet of the upper microchannel heat sink.

6. The microchannel heat dissipation device with a composite structure as described in claim 1, wherein The thickness of the microchannel heat sink is 500μm - 600μm, the thickness of the fin and the width of the microgroove between adjacent fins are 10μm - 20μm, and the depth of the microgroove is 350μm - 450μm; the inclined groove forms a 45° angle with the fin edge, the width is 50μm - 60μm, the inclined groove is shallowly etched and the etching depth is 20μm - 30μm, and the long axis direction of the rhombohedron is the same as the direction of the inclined groove.

7. The microchannel heat dissipation device with a composite structure according to claim 6, characterized in that, The directions of the inclined grooves at the top of the fins are arranged symmetrically along the centers of the manifold inlet channel and the manifold outlet channel.

8. The microchannel heat dissipation device with a composite structure according to claim 1, characterized in that, The top surface of the manifold shunt device is bonded and packaged with the bottom surface of the microchannel heat sink, and the top surfaces of the inclined grooves and the rhombohedrons are bonded and packaged with the bottom surface of the chip. The bonding methods include one of direct bonding, Au - Sn wafer bonding, Au - Si wafer bonding, and Au - In wafer bonding.

9. The microchannel heat dissipation device with a composite structure according to claim 1, characterized in that, The materials of the microchannel heat sink and the manifold shunt device include one or a combination of silicon, aluminum nitride, silicon carbide, and diamond. The cooling fluid flowing in the microchannel heat sink and the manifold shunt device includes one of deionized water, liquid nitrogen, liquid helium, and liquid metal.

10. A heat dissipation method for a microchannel heat dissipation device based on the composite structure according to any one of claims 1 to 9, characterized in that, It includes: Step 1: The cooling fluid horizontally enters the manifold inlet channel through the two end inlets of the channel, and then the fluid rises from the microchannel bottom inlet array of the microchannel heat sink and vertically impacts the bottom surface of the chip in the form of a jet array along the fin wall surface; Step 2: The fluid diverges from the center to both sides along the bottom surface of the chip and the side wall of the fin, and flows around the top inclined groove and the rhombohedron of the fin, respectively forming a high-density secondary flow array and an ultra-thin boundary layer; Step 3: The fluid meets at the center of the area opposite to the microchannel bottom outlet, turns back downward, and reaches the manifold outlet channel along the microchannel bottom outlet, and then flows out vertically downward to complete a convective heat transfer cycle.

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