Embedded liquid cooling chip with manifold structure by laser direct writing and preparation method thereof

Abstract

This invention discloses an embedded liquid-cooled chip with a manifold structure and its fabrication method using laser direct writing. The chip includes an active chip and a manifold template. The active chip has an active device side and a channel side on its two sides, respectively. The active device side is equipped with transistor circuits that implement electrical functions, and the channel side surface is processed with liquid cooling channels. The manifold template is a single-board structure or a stacked board structure. This invention replaces the patterned photolithography method with a laser direct writing method for fabricating embedded liquid-cooled chips with manifold structures, solving the problems of low flexibility and high production cost of the patterned photolithography method in small-batch production of embedded liquid-cooled chips with manifold structures. This achieves low-cost and highly flexible fabrication of embedded liquid-cooled chips with manifold structures.

Description

Technical Field

[0001] This invention relates to the field of semiconductor liquid cooling technology, specifically to an embedded liquid-cooled chip with a manifold structure and its fabrication method that uses laser direct writing. Background Technology

[0002] Driven by demands for both computing performance and portability, the heat flux density of semiconductor chips has been increasing year by year. However, heat dissipation issues significantly limit the improvement of chip performance. Higher junction temperatures can significantly reduce the reliability of semiconductor devices. Traditional air-cooling solutions are no longer sufficient to meet the needs of future high heat flux density chips. Embedded liquid cooling technology targeting transistor-level heat sources is the ideal heat dissipation solution for future semiconductor chips. This solution is based on microelectromechanical systems (MEMS) technology and typically places liquid cooling channels near transistors to greatly reduce thermal resistance and enhance the performance of liquid cooling.

[0003] Currently, embedded liquid cooling solutions utilize cooling channels entirely on the chip, a process known as "near-node cooling," unlike "far-end cooling" where cooling channels are located on a cold plate. Because cooling channels need to be fabricated on hard and brittle materials like single-crystal silicon, patterned photolithography is a common processing method. To achieve better overall cooling performance, manifold structures are needed to balance the voltage drop in the chip-side cooling system caused by enhanced cooling. The complex manifold structure further complicates the patterned photolithography process. Therefore, patterned photolithography is not well-suited to the manufacturing requirements of embedded liquid-cooled chip thermal design, development, and debugging phases. This approach lacks flexibility in small-batch production and debugging, and is also costly. Summary of the Invention

[0004] To overcome the aforementioned shortcomings and deficiencies of the prior art, the present invention aims to provide an embedded liquid-cooled chip with a manifold structure and its fabrication method using laser direct writing. This method enables the fabrication of high-performance embedded liquid-cooled chips with high flexibility and low processing cost.

[0005] The objective of this invention is achieved through the following technical solution: An embedded liquid-cooled chip with a manifold structure and laser direct writing includes an active chip and a manifold template. The two sides of the active chip are an active device side and a channel side, respectively. The active device side is provided with transistor circuits that realize electrical functions, and the surface of the channel side is processed with liquid cooling channels. The manifold template is a single-plate structure or a stacked-plate structure; When the manifold template is a single-board structure, it is made of the same material as the active chip, and the single-board structure is provided with hollow partitioned flow channels. When the manifold template is a stacked plate structure, the stacked plate structure includes an upper cover plate, an intermediate plate and a contact plate. The upper cover plate is provided with two pairs of coolant inlets and coolant outlets. The intermediate plate integrates a guide fluid channel and a confluence channel. The contact plate is provided with a manifold structure and a confluence manifold that match the liquid cooling channel on the side surface of the active chip channel.

[0006] Furthermore, the channel side of the active chip is bonded to one side of the single-board structure via an anodic bonding process to form an embedded liquid-cooled chip with a manifold structure.

[0007] Furthermore, when the material of the stacked structure is metal or plastic, the contact plate and the active chip are watertight by adhesive sealing material. Then the top cover plate and the middle plate are connected and fixed by adhesive sealing material to form an embedded liquid-cooled chip with a manifold structure.

[0008] Furthermore, when the stacked structure uses the same material as the active chip, such as monocrystalline silicon, it is bonded to the active chip to form an integrated whole, creating an embedded liquid-cooled chip with a manifold structure.

[0009] Furthermore, the cooling process for the embedded liquid-cooled chip with a manifold structure, formed by bonding the active chip to the manifold template of the stacked structure, is as follows: The coolant enters the flow channel of the intermediate plate from the coolant inlet of the top cover plate, and then reaches the manifold structure in the contact plate. Under the action of the manifold structure, it is evenly distributed to each liquid cooling channel of the active chip. After absorbing the heat of the chip heat source in the liquid cooling channel, the coolant returns through the internal manifold of the contact plate, merges into the flow channel of the intermediate plate, and finally is discharged through the coolant outlet of the top cover plate, thus completing the uniform heat dissipation of the active chip.

[0010] Furthermore, the size and arrangement of the liquid cooling channels are determined based on the power of the active device side.

[0011] A method for fabricating the embedded liquid-cooled chip with the manifold structure includes the following steps: Laser direct writing is used to process liquid cooling channels on the channel side of active chips; For the processing of manifold modules, if it is a single-board structure, laser direct writing is used; if it is a stacked structure, laser direct writing or CNC machining is used. The processed active chip is assembled with the manifold template.

[0012] Furthermore, when the material of the stacked structure is the same as that of the active chip, laser direct writing processing is used; When the laminated structure is made of metal or other materials, it is machined using CNC machining.

[0013] Furthermore, prior to processing, a silicon oxide layer is thermally grown on the channel side to protect the unprocessed surface.

[0014] Furthermore, the laser direct writing specifically employs a picosecond laser or a nanosecond laser.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) This invention replaces the patterned photolithography scheme with a laser direct writing scheme to process the coolant channel of an embedded liquid-cooled chip with a manifold structure. This solves the problems of low flexibility and high production cost of the patterned photolithography scheme in the small-batch production of embedded liquid-cooled chips with a manifold structure. It realizes the preparation of embedded liquid-cooled chips with a manifold structure in a low-cost and highly flexible manner. (2) The manifold template adopts two schemes: single-board structure and stacked board structure. The manifold template is fabricated separately from the liquid cooling channel on the active chip, so that the manifold template structure is not limited to the liquid cooling channel structure on the active chip. At the same time, the stacked board structure further expands the diversity of manifold channels, and complex manifold structures can be realized through simple processes; (3) The stacked structure of the manifold template adopts a dual coolant inlet / outlet design on the top cover plate, a fluid channel in the middle plate and a distribution manifold on the contact plate, which significantly improves the problem of uneven coolant distribution, ensures that the coolant flows evenly through each liquid cooling channel, and improves the uniformity of chip heat dissipation and overall heat dissipation efficiency. (4) Each component can be designed using semiconductor materials such as single crystal silicon. Precise size control is achieved through laser direct writing. Combined with the dual sealing method of anodic bonding and adhesive sealing, the sealing performance and structural stability of the liquid cooling channel are ensured, and the service life of the chip is extended. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of an embedded liquid-cooled chip with a manifold structure that is laser-written in an embodiment of the present invention. Figure 2 This is a schematic diagram of an active chip structure with a liquid cooling channel fabricated on the channel side in an embodiment of the present invention; Figure 3 This is a schematic diagram of a single-plate structure with a hollow partitioned flow channel in an embodiment of the present invention; Figure 4 This is a schematic diagram of the bonding method between the active chip and the single-board structure in an embodiment of the present invention; Figure 5 This is a schematic diagram of the working flow direction of the coolant after the active chip is bonded to the single-board structure in an embodiment of the present invention; Figure 6 This is a schematic diagram of the stacked plate structure in an embodiment of the present invention; Figure 7 This is a schematic diagram of the working flow direction of the coolant after the active chip and the stacked structure are bonded in an embodiment of the present invention; Figure 8This is a schematic diagram of the process flow for fabricating an embedded liquid-cooled chip with a manifold structure in an embodiment of the present invention. Detailed Implementation

[0017] The present invention is further described below through specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0018] Example

[0019] like Figure 1 and Figure 2 As shown, an embedded liquid-cooled chip with a manifold structure and laser direct writing includes an active chip 1 and a manifold template 2. The active chip 1 has an active device side 11 and a channel side 12 on its two sides, respectively. The active device side 11 has transistor circuits that realize electrical functions. Multiple liquid-cooling channels 13 are processed on the surface of the channel side 12. The size and arrangement of the liquid-cooling channels are determined according to the power of the active device side 11. Their shapes include, but are not limited to, parallel microchannels, serpentine microchannels, loop-shaped microchannels, and coolant channels with various special structures. The manifold template 2 has two types: single-plate structure and stacked plate structure. The single-plate structure manifold template is made of the same material as the active chip 1, while the stacked plate structure manifold template can be made of a different material than the active chip 1.

[0020] like Figure 3 As shown, the single-plate structure 2A of the manifold template is a single plate, and its surface is machined with hollow partition channels 2A1 for forming the manifold channel structure.

[0021] like Figure 4 As shown, the channel side 12 of the active chip 1 is bonded to the manifold template 2 through an anodic bonding process. Specifically, it is connected to one side of the single board structure 2A through an anodic bonding to form an embedded liquid-cooled chip with a manifold structure.

[0022] like Figure 5 As shown, the embedded liquid-cooled chip with a manifold structure formed by bonding the active chip 1 to the single-board structure 2A forms a coolant inlet 2A2 and a coolant outlet 2A3. The coolant enters the embedded liquid-cooled chip with the manifold structure from the coolant inlet 2A2. Under the action of the hollow partition channel 2A1, the low-temperature coolant enters the liquid-cooled channel 13 on the channel side of the active chip 1, thereby absorbing the heat source of the transistor circuit on the active device side 11. The coolant that has been heated after absorbing heat gathers under the action of the hollow partition channel 2A1 and flows out from the coolant outlet 2A3, thereby realizing the heat dissipation effect on the active chip.

[0023] like Figure 6As shown, the stacked structure 2B of the manifold template consists of an upper cover plate 2B1, an intermediate plate 2B2, and a contact plate 2B3. The upper cover plate 2B1 is provided with a pair of symmetrically distributed coolant inlets 2B11 and a pair of symmetrically distributed coolant outlets 2B12. The intermediate plate 2B2 integrates a guide fluid channel 2B21 and a confluence channel 2B22. The contact plate 2B3 is provided with a manifold structure 2B31 that matches the liquid cooling channel 13 on the surface of the channel side 12 of the active chip 1 and a confluence manifold 2B32.

[0024] like Figure 7 As shown, the cooling process of the embedded liquid-cooled chip with manifold structure formed by bonding the active chip 1 and the stacked structure 2B of the manifold template is as follows: the coolant enters the guide fluid channel 2B21 of the intermediate plate 2B2 from the two pairs of symmetrical coolant inlets 2B11 of the upper cover plate 2B1, and then reaches the manifold structure 2B31 in the contact plate 2B3. Under the action of the manifold structure 2B31, it is evenly distributed to each liquid-cooling channel 13 of the active chip 1. After absorbing the heat of the chip heat source in the liquid-cooling channel 13, the coolant returns through the internal manifold 2B32 of the contact plate 2B3, merges into the manifold channel 2B22 of the intermediate plate 2B2, and finally is discharged through the symmetrical outlet 2B12 of the upper cover plate 2B1, thus completing the efficient and uniform heat dissipation of the active chip.

[0025] like Figure 8 A method for fabricating an embedded liquid-cooled chip with a manifold structure using laser direct writing includes the following steps: Step S1: A liquid cooling channel 13 is processed on the channel side 12 of the active chip using a laser. Specifically, the active chip 1 is a single crystal silicon. First, a silicon oxide layer is thermally grown on the channel side 12 to protect the non-processed surface. Then, multiple liquid cooling channels 13 are directly written using a laser. The processed active chip 1 sample is immersed in a mixed solution of hydrofluoric acid, nitric acid, and acetic acid to remove the silicon oxide protective layer and trim the processed surface in preparation for subsequent assembly processes.

[0026] Step S2: The single-board structure 2A of the laser-written manifold template is used for laser-written (the stacked structure 2B is made of hard and brittle semiconductor materials such as single crystal silicon) or CNC-processed (the stacked structure 2B is made of common materials that are easy to CNC process such as metal and plastic). The top cover plate 2B1, middle plate 2B2 and contact plate 2B3 of the stacked structure 2B are processed by laser writing (the stacked structure 2B is made of hard and brittle semiconductor materials such as single crystal silicon) or CNC processing (the stacked structure 2B is made of common materials that are easy to CNC process such as metal and plastic). The processed single-plate structure sample 2A and stacked structure 2B (if the stacked structure is monocrystalline silicon) are both immersed in a mixed solution of hydrofluoric acid, nitric acid and acetic acid to remove the silicon oxide protective layer and trim the laser-processed structure in preparation for the subsequent assembly process.

[0027] Step S3: The active chip 1 is assembled with the manifold template 2. Specifically, for the single-board structure 2A, the active chip channel side 12 is bonded to the single-board structure 2A of the manifold template 2 through anodizing bonding process to complete the assembly. For the stacked structure 2B, the contact plate 2B3 and the chip are combined through anodizing bonding (stacked structure 2B is monocrystalline silicon) or adhesive sealing material (stacked structure 2B is metal or plastic). Then, the upper cover plate 2B1 and the middle plate 2B2 are connected and fixed through anodizing bonding (stacked structure 2B is monocrystalline silicon) or adhesive sealing material (stacked structure 2B is metal or plastic) to form an embedded liquid-cooled chip with a manifold structure.

[0028] Those skilled in the art will readily understand that the above description is merely an embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An embedded liquid-cooled chip with a manifold structure that is laser-written, characterized in that, It includes an active chip and a manifold template. The active chip has an active device side and a channel side on its two sides, respectively. The active device side is provided with a transistor circuit that realizes electrical functions, and the channel side surface is processed with a liquid cooling channel. The manifold template is a single-plate structure or a stacked-plate structure; When the manifold template is a single-board structure, it is made of the same material as the active chip, and the single-board structure is provided with hollow partitioned flow channels. When the manifold template is a stacked structure, the stacked structure includes an upper cover plate, an intermediate plate and a contact plate. The upper cover plate is provided with two pairs of symmetrically distributed coolant inlets and coolant outlets. The intermediate plate integrates a flow guiding channel and a confluence channel. The contact plate is provided with a manifold structure and a confluence manifold that match the liquid cooling channel on the side surface of the active chip channel.

2. The embedded liquid-cooled chip according to claim 1, characterized in that, The channel side of the active chip is bonded to one side of the single-board structure through an anodic bonding process to form an embedded liquid-cooled chip with a manifold structure.

3. The embedded liquid-cooled chip according to claim 1, characterized in that, When the stacked structure is made of metal or plastic, the contact plate and the active chip are watertight by adhesive sealing material. Then the top cover plate and the middle plate are connected and fixed by adhesive sealing material to form an embedded liquid-cooled chip with a manifold structure.

4. The embedded liquid-cooled chip according to claim 3, characterized in that, When the stacked structure uses the same material as the active chip, it is bonded to the active chip to form an integral whole, creating an embedded liquid-cooled chip with a manifold structure.

5. The embedded liquid-cooled chip according to claim 3, characterized in that, The cooling process for the embedded liquid-cooled chip with a manifold structure, formed by bonding an active chip to a stacked manifold template, is as follows: The coolant enters the flow channel of the middle plate from the coolant inlet of the top cover plate, and then reaches the manifold structure in the contact plate. Under the action of the manifold structure, it is evenly distributed to each liquid cooling channel of the active chip. After absorbing heat from the chip's heat source within the liquid cooling channel, the coolant returns through the internal manifold of the contact plate, flows into the manifold of the intermediate board, and is finally discharged through the coolant outlet of the top cover plate, thus completing the uniform heat dissipation of the active chip.

6. The embedded liquid-cooled chip according to claim 1, characterized in that, The size and arrangement of the liquid cooling channels are determined based on the power of the active device.

7. A method for fabricating an embedded liquid-cooled chip according to any one of claims 1-6, characterized in that, Includes the following steps: Laser direct writing is used to process liquid cooling channels on the channel side of active chips; For the processing of manifold modules, if it is a single-board structure, laser direct writing is used; if it is a stacked structure, laser direct writing or CNC machining is used. The processed active chip is assembled with the manifold template.

8. The preparation method according to claim 7, characterized in that, When the stacked structure uses the same material as the active chip, laser direct writing is used; When the laminated structure is made of metal or other materials, it is machined using CNC machining.

9. The preparation method according to claim 7, characterized in that, Before processing, a silicon oxide layer is thermally grown on the channel side to protect the unprocessed surface.

10. The preparation method according to claim 7, characterized in that, The laser direct writing specifically uses picosecond lasers or nanosecond lasers.

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