Multistage sealing fluid interconnection device of liquid cooling heat dissipation chip

Abstract

The invention discloses a multi-stage sealing fluid interconnection device of a liquid cooling heat dissipation chip, and relates to the technical field of advanced heat management of electronic equipment.A multi-stage sealing connection method is adopted, the huge space requirements of a liquid supply port and a liquid return port of an existing liquid cooling heat dissipation chip are omitted, and the heat dissipation efficiency of the liquid cooling heat dissipation chip is improved. And after the liquid supply ports and the liquid return ports of the plurality of chips are switched through the switching plate, a total liquid supply port and a total liquid return port are formed. According to the invention, the liquid supply and return interface and the adapter for fluid transportation are integrated in the chip and the connection layer structure, so that the connection reliability is improved, no extra space is occupied, and the problems that the external interface is too large in size and cannot be highly integrated and expanded are solved. Through the multi-stage sealing structure, the fit clearance is controlled to be in the magnitude of 10 microns, the pressure can be greatly reduced when a cooling medium in a channel leaks outwards along the multi-stage sealing structure under the pressure effect, and meanwhile the liquid sealing effect is achieved. And in combination with BGA reflow soldering, efficient and reliable sealing connection can be realized.

Description

Technical Field

[0001] The present invention relates to the field of advanced thermal management technology for electronic devices, and particularly to a multi-stage sealed fluid interconnection device for a liquid-cooled heat dissipation chip. Background Art

[0002] With the rapid development of 3D packaging technology, the chip integration density and heat dissipation increase synchronously, and the heat dissipation problem has become the key bottleneck restricting the reliability of devices. In the prior art, although the through-silicon via (TSV) and embedded cooling technologies (such as intra-chip / inter-chip microfluidic cooling) can relieve the heat dissipation pressure, their engineering applications face two major problems:

[0003] Insufficient reliability of fluid transport: The traditional liquid-cooled chip is connected to the external pipeline through a top organic dielectric adapter. The adapter has a large size, low integration density, and a complex sealing process.

[0004] Poor process compatibility: The existing solutions require special process treatment for the sealed connection between the chip and the external pipeline, and it is difficult to be compatible with the standard BGA (ball grid array) reflow soldering process.

[0005] Therefore, there is an urgent need for a fluid interconnection technology with high reliability, high integration, and process compatibility. Summary of the Invention

[0006] The present invention provides a multi-stage sealed fluid interconnection device for a liquid-cooled heat dissipation chip, which realizes efficient sealing of fluid transport, reduces the risk of leakage, is compatible with the existing BGA reflow soldering process, and avoids corrosion caused by the contact between the solder and the cooling medium.

[0007] To achieve the above object, a multi-stage sealed fluid interconnection device for a liquid-cooled heat dissipation chip provided by the present invention includes:

[0008] A liquid-cooled heat dissipation chip, which is provided with spherical BGA solder balls for power supply / signal transmission, a liquid supply interface, a liquid return interface, and annular BGA solder balls around the liquid supply interface and the liquid return interface at the bottom.

[0009] An adapter board, whose surface is provided with pads corresponding to the spherical BGA solder balls and annular BGA solder balls of the liquid-cooled heat dissipation chip, as well as a total liquid supply port, a liquid supply channel, an adapter board liquid supply port, an adapter board liquid return port, a converging channel, and a total liquid return port.

[0010] A multi-stage sealing structure, which is formed by the insertion tooth fit between the liquid supply interface and the liquid return interface of the liquid-cooled heat dissipation chip and the adapter board liquid supply port and the adapter board liquid return port. The insertion tooth fit structure includes a plurality of micro-grooves provided at the liquid supply interface and the liquid return interface, and the number of the micro-grooves is 2 to 4.

[0011] The height of the annular BGA solder ball is higher than the liquid supply interface and the liquid return interface of the liquid cooling chip, and is welded to the adapter plate through a reflow soldering process to form a sealed connection;

[0012] The transfer plate is provided with an inclined groove near the annular BGA solder ball, which is used to guide the solder to flow along the multi-level sealing structure.

[0013] In some embodiments, the tooth fitting clearance of the multi-stage sealing structure is 5 to 20 μm.

[0014] In some embodiments, the material of the adapter plate is selected from a micro-substrate, a high temperature co-fired ceramic, or a low temperature co-fired ceramic.

[0015] In some embodiments, the micro grooves of the liquid supply interface and the liquid return interface of the liquid-cooled heat dissipation chip are rectangular, trapezoidal or arc-shaped.

[0016] In some embodiments, the cooling medium is a fluorocarbon medium with low electrical conductivity.

[0017] In some embodiments, the soldering material of the annular BGA solder ball is a tin-silver-copper alloy or a tin-bismuth alloy.

[0018] In some embodiments, the total liquid supply port of the adapter plate distributes the cooling medium into multiple branches through a liquid supply channel, each branch is connected to the corresponding liquid supply port of the liquid cooling chip, and the return liquid ports are collected to the total return liquid port through a collecting channel.

[0019] Compared with the related art, the multi-stage sealed fluid interconnection device of a liquid cooling heat dissipation chip provided by the present invention has the following beneficial effects:

[0020] The present invention provides a multi-stage sealed fluid interconnection device for a liquid cooling heat dissipation chip, adopts a multi-stage sealed connection method, eliminates the current huge liquid supply port and liquid return port space requirements of the liquid cooling chip heat dissipation chip, and forms a total liquid supply port and liquid return port after the liquid supply ports and liquid return ports of multiple chips are transferred through an adapter plate. The present invention integrates the liquid supply and return interface and the transfer interface used for fluid transportation inside the chip and the connection layer structure, improves the reliability of the connection, does not occupy additional space, and solves the problem that the external interface size is too large and cannot be highly integrated and expanded.

[0021] The present invention controls the matching gap at the order of 10 μm through a multi-stage sealing structure, which can significantly reduce the pressure of the cooling medium in the channel when it leaks to the outside along the multi-stage sealing structure under pressure, and has a liquid sealing effect. Combined with BGA reflow soldering, efficient and reliable sealing connection can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 Schematic diagram of the bottom structure of the liquid-cooled heat dissipation chip of the present invention;

[0024] Figure 3 Schematic diagram of the adapter board structure of the present invention;

[0025] Figure 4 Schematic cross-sectional view of the interface of the liquid-cooled heat dissipation chip of the present invention;

[0026] Figure 5 Schematic diagram of the connection structure between the liquid-cooled heat dissipation chip and the adapter board of the present invention.

[0027] Reference numerals in the figure: 1. Adapter board; 2. Liquid-cooled heat dissipation chip; 3. Liquid-cooling channel; 4. Inserted teeth; 5. Through-silicon via; 6. Inclined groove; 7. Solder; 8. Micro-groove; 11. Total liquid return port; 12. Total liquid supply port; 13. Liquid supply flow channel; 14. Converging flow channel; 15. Adapter board liquid supply port; 16. Adapter board liquid return port; 21. Liquid supply interface; 22. Liquid return interface; 23. Spherical BGA solder ball; 24. Ring-shaped BGA solder ball. Detailed implementation manners

[0028] Embodiment 1 (basic structure)

[0029] As Figures 1-5 shown, this embodiment includes:

[0030] Liquid-cooled heat dissipation chip 2:

[0031] Spherical BGA solder balls 23: Distributed at the bottom of the chip for power supply, radio frequency and control signal transmission;

[0032] Ring-shaped BGA solder balls 24: Arranged around the liquid supply interface 21 and the liquid return interface 22, with a height 5 - 10 μm higher than the interfaces;

[0033] Micro-grooves 8: 2 - 4 concentric annular grooves (depth 10 - 30 μm, width 20 - 50 μm) are arranged between the liquid supply interface 21 and the liquid return interface 22.

[0034] Adapter board 1:

[0035] Material: Micro-generation board, high-temperature co-fired ceramic (HTCC) or low-temperature co-fired ceramic (LTCC);

[0036] Fluid channel:

[0037] The cooling medium flows from the total liquid supply port 12 → the liquid supply flow channel 13 → the adapter board liquid supply port 15 → the chip liquid supply interface 21;

[0038] The chip liquid return interface 22 → the adapter board liquid return port 16 → the converging flow channel 14 → the total liquid return port 11.

[0039] Multi - stage sealing structure:

[0040] After the chip 2 and the adapter board 1 are inserted into each other at the interface, the micro - grooves 8 form a multi - stage sealing surface 4;

[0041] Inclined groove 6: An inclined angle of 5 - 15° is set around the annular BGA solder ball 24 to guide the solder 7 to fill the gap.

[0042] Example 2 (Optimization of adapter board material and sealing)

[0043] Adapter board 1: Adopt HTCC (thermal expansion coefficient 3.5 ppm / °C) to reduce thermal stress;

[0044] Sealing structure:

[0045] Four trapezoidal micro - grooves 8 (depth 25 μm, upper base 30 μm, lower base 50 μm) are set at the liquid supply interface 21 and the liquid return interface 22;

[0046] The adapter board 1 is machined with matching bosses 4 at the corresponding positions.

[0047] Inclined groove 6: Inclined angle 12°, and the solder 7 is Sn96.5Ag3.0Cu0.5 alloy.

[0048] Application: High - reliability 3D packaging scenarios such as aerospace electronics.

[0049] Example 3 (Low - cost miniaturization solution)

[0050] Adapter board 1: Adopt LTCC and integrate an embedded temperature sensor;

[0051] Sealing structure:

[0052] Two arc - shaped micro - grooves 8 (radius 15 μm, depth 18 μm) are set at the liquid supply interface 21;

[0053] The groove of the adapter board 1 is a complementary arc.

[0054] Fluid channel: The liquid supply port 15 of the adapter board adopts a tree - shaped fractal liquid supply flow channel 13, and the pressure drop is reduced by 10%;

[0055] Solder 7: Sn42Bi58 alloy (melting point 138 °C).

[0056] Application: Mobile phone / tablet chip packaging.

[0057] Example 4 (Adaptation to high power density)

[0058] Sealing structure:

[0059] The liquid supply interface 21 adopts a 3 - stage stepped rectangular micro - groove 8 (depth 10 / 15 / 20 μm);

[0060] The total liquid supply port 12 of the adapter board 1 is embedded with a piezoelectric micropump.

[0061] Anti-corrosion: The surface of the inclined groove 6 is plated with a nickel-gold layer (2μm);

[0062] Cooling medium: 3M Novec 7100.

[0063] Application: GPU / CPU liquid cooling and heat dissipation.

[0064] Example Five (Multi-chip array interconnection)

[0065] Adapter board 1: 4×4 chip array, the flow channels 13 and 14 are symmetrically spirally distributed;

[0066] Sealing structure:

[0067] Each liquid supply interface 21 / liquid return interface 22 is provided with 3 V-shaped micro-grooves 8 (angle 60°, depth 20μm);

[0068] Welding process: Stepwise temperature rise (150°C → 200°C → 235°C), void ratio < 3%;

[0069] Cooling medium: Ionic liquid [EMIM][TFSI].

[0070] Test result: When the power consumption of a single chip is 300W, the temperature rise of the coolant ≤ 15°C.

[0071] Working principle:

[0072] 1. Multi-stage sealing function: When the cooling medium leaks from the liquid cooling channel 3, the pressure gradually decays through the multi-stage sealing surface 4 to < 10% of the initial value;

[0073] 2. Oil film sealing: The sealing gap is 10μm, and the leakage is inhibited by the viscous resistance of the liquid;

[0074] 3. BGA process compatibility: After the annular BGA solder balls 24 melt, they fill the gaps of the broaching teeth 4 to form a solder 7 sealing layer;

[0075] 4. Anti-corrosion design: The inclined groove 6 blocks the solder 7 from flowing into the liquid cooling channel 3 to avoid contact with the cooling medium.

Claims

1. A multi-stage sealed fluid interconnection device for a liquid cooling heat dissipation chip, characterized in that: include: A liquid cooling heat dissipation chip, the bottom of which is provided with a spherical BGA solder ball for power supply / signal transmission, a liquid supply interface, a liquid return interface, and a ring-shaped BGA solder ball surrounding the liquid supply interface and the liquid return interface; An adapter plate, the surface of which is provided with pads corresponding to the spherical BGA solder balls and the annular BGA solder balls of the liquid cooling and heat dissipation chip, as well as a total liquid supply port, a liquid supply flow channel, an adapter plate liquid supply port, an adapter plate liquid return port, a collecting flow channel and a total liquid return port; A multi-stage sealing structure is formed by the spline matching between the liquid supply interface and the liquid return interface of the liquid cooling heat dissipation chip and the liquid supply port and the liquid return port of the adapter plate, and the spline matching structure includes a plurality of micro grooves arranged at the liquid supply interface and the liquid return interface, and the number of the micro grooves is 2 to 4; The height of the annular BGA solder ball is higher than the liquid supply interface and the liquid return interface of the liquid cooling chip, and is welded to the adapter plate through a reflow soldering process to form a sealed connection; The transfer plate is provided with an inclined groove near the annular BGA solder ball, which is used to guide the solder to flow along the multi-level sealing structure.

2. A multi-stage sealed fluid interconnection device for a liquid cooling heat dissipation chip according to claim 1, characterized in that: The insert tooth matching clearance of the multi-stage sealing structure is 5 to 20 μm.

3. The multi-stage sealed fluid interconnection device of a liquid cooling heat dissipation chip according to claim 1, characterized in that: The material of the adapter plate is selected from one of micro-substrate board, high temperature co-fired ceramic or low temperature co-fired ceramic.

4. The multi-stage sealed fluid interconnection device of a liquid cooling heat dissipation chip according to claim 1, characterized in that: The micro grooves of the liquid supply interface and the liquid return interface of the liquid cooling heat dissipation chip are in a rectangular, trapezoidal or arc shape.

5. The multi-stage sealed fluid interconnection device of a liquid cooling heat dissipation chip according to claim 1, characterized in that: The cooling medium is a fluorocarbon medium with low electrical conductivity.

6. The multi-stage sealed fluid interconnection device of a liquid cooling heat dissipation chip according to claim 1, characterized in that: The welding material of the annular BGA solder ball is tin-silver-copper alloy or tin-bismuth alloy.

7. The multi-stage sealed fluid interconnection device for a liquid cooling heat dissipation chip according to claim 1, characterized in that: The total liquid supply port of the adapter plate distributes the cooling medium into multiple branches through the liquid supply channel, each branch is connected to the corresponding liquid supply port of the liquid cooling chip, and the return liquid ports are collected to the total return liquid port through the collecting channel.

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