Patent Application
20240203824
This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2022-0179736, filed on Dec. 20, 2022, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.
The disclosure relates to a semiconductor device having a cooling structure.
Generally, in electronic devices, such as computers, air cooling devices have been commonly used to remove heat generated from the electronic devices. As the power density of electronic devices has been gradually increased, the use of cooling devices to cope with the raised heating value has also increased. In addition, in case of a data center, there is a growing interest in next-generation cooling methods with high efficiency, such as a liquid cooling device to reduce the power consumption. Cooling methods may be divided into a single-phase liquid cooling method, which does not involve a phase change of a coolant according to a temperature range of a heat-generating portion, and a two-phase liquid cooling method, which is accompanied by a phase change of a coolant. The two-phase cooling method has a wider capable range of heating value than the single-phase method.
Provided is a semiconductor device with a two-phase cooling structure.
Provided is a semiconductor device with a two-phase cooling structure capable of removing vapors attached to a heat transfer surface of a semiconductor chip.
Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.
According to an aspect of the disclosure, there is provided a semiconductor device including: a semiconductor chip including a semiconductor integrated circuit; a cooling channel formed in the semiconductor chip, the cooling channel configured to provide a path for moving a coolant; and an ultrasonic vibrator arranged in the cooling channel and configured to vibrate the coolant.
The ultrasonic vibrator may be at least partially provided in the coolant in the cooling channel.
The ultrasonic vibrator may be arranged on a heat transfer surface adjacent to the semiconductor integrated circuit of the cooling channel.
The ultrasonic vibrator may extend in a transverse direction parallel with the heat transfer surface.
The ultrasonic vibrator may extend from the heat transfer surface in a thickness direction of the semiconductor chip.
The ultrasonic vibrator may include a plurality of ultrasonic vibrators.
The semiconductor device may further include: a capillary pattern configured to move the coolant by a capillary force, wherein the capillary pattern is formed on at least a part of a wall of the cooling channel.
The capillary pattern may be formed on a heat transfer surface adjacent to the semiconductor integrated circuit of the cooling channel.
The ultrasonic vibrator may include a plurality of ultrasonic vibrators, and wherein the plurality of ultrasonic vibrators form a capillary pattern configured to the coolant by a capillary force in the cooling channel.
The ultrasonic vibrator may extend in a thickness direction of the semiconductor chip from a heat transfer surface adjacent to the semiconductor integrated circuit of the cooling channel.
The ultrasonic vibrator may include a micro-machined ultrasonic transducer.
The semiconductor chip may include a first semiconductor chip and a second semiconductor chip stacked on the first semiconductor chip, wherein the cooling channel may include a first cooling channel provided in the first semiconductor chip and a second cooling channel provided in the second semiconductor chip, wherein the ultrasonic vibrator may include a first ultrasonic vibrator provided in the first semiconductor chip and a second ultrasonic vibrator provided in the second semiconductor chip.
According to another aspect of the disclosure, there is provided a semiconductor device including: a semiconductor chip including a substrate and a semiconductor integrated circuit formed on a first surface of the substrate; a cooling channel formed on the substrate, the cooling channel configured to provide a path for moving a coolant; and a micro-machined ultrasonic transducer arranged at least partially provided in the coolant in the cooling channel and configured to vibrate the coolant.
The semiconductor device may further include: a capillary pattern configured to move the coolant by a capillary force in the cooling channel, wherein the capillary pattern is formed on at least a part of a wall of the cooling channel.
The micro-machined ultrasonic transducer may be arranged on a heat transfer surface adjacent to the semiconductor integrated circuit of the cooling channel.
The micro-machined ultrasonic transducer may include a plurality of micro-machined ultrasonic transducers, and wherein the plurality of micro-machined ultrasonic transducers may form the capillary pattern configured to move the coolant.
The micro-machined ultrasonic transducer may extend in a thickness direction of the semiconductor chip from a heat transfer surface adjacent to the semiconductor integrated circuit of the cooling channel.
The micro-machined ultrasonic transducer may include a piezoelectric micro-machined transducer (pMUT).
The semiconductor chip may include a first semiconductor chip and a second semiconductor chip stacked on the first semiconductor chip, wherein the cooling channel includes a first cooling channel provided in the first semiconductor chip and a second cooling channel provided in the second semiconductor chip, wherein the micro-machined ultrasonic transducer includes a first micro-machined ultrasonic transducer provided in the first semiconductor chip and a second micro-machined ultrasonic transducer provided in the second semiconductor chip.
According to an aspect of the disclosure, there is provided an electronic device including: a substrate including a plurality of electronic components; a cooling channel formed in the substrate, the cooling channel configured to provide a path for moving a coolant; and a vibrator arranged in the cooling channel and configured to vibrate the coolant.
The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.
Hereinafter, example embodiments will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals in the drawings denote like elements, and sizes of components in the drawings may be exaggerated for clarity and convenience of explanation. Meanwhile, embodiments described below are provided only as an example, and thus can be embodied in various forms. It will be understood that when a component is referred to as being “on” or “over” another component, the component can be directly on, under, on the left of, or on the right of the other component, or can be on, under, on the left of, or on the right of the other component in a non-contact manner. An expression used in the singular encompasses the expression of the plural, unless it has a clearly different meaning in the context. When a portion “includes” an element, another element may be further included, rather than excluding the existence of the other element, unless otherwise described. The use of the terms “a” and “an” and “the” and similar referents in the context of describing embodiments (especially in the context of the following claims) are to be construed to cover both the singular and the plural. The operations of all methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context, and embodiments are not limited to the described order of the operations. Moreover, the terms “part,” “module,” etc. refer to a unit processing at least one function or operation, and may be implemented by a hardware, a software, or a combination thereof. The connecting lines, or connectors shown in the various figures presented are intended to represent exemplary functional relationships and/or physical or logical couplings between the various elements, and thus it should be noted that many alternative or additional functional relationships, physical connections or logical connections may be present in a practical device. The use of any and all examples, or exemplary language provided herein, is intended merely to better illuminate technical ideas and does not pose a limitation on the scope of embodiments unless otherwise claimed.
In order to address a cooling problem that has been a limiting factor in the performance of electronic devices including semiconductor devices an efficient cooling system is required. For example, high performance computing (HPC) fields and semiconductor devices are implemented with stacked three-dimensional semiconductor integrated circuits in an highly integrated manner resulting in increased power density and increased heat generation. As such, a cooling system capable of responding to an increase in power density and an increase in heat generation due to high integration of the stacked three-dimensional semiconductor integrated circuits and other electronic components is required. In order to meet these demands, a two-phase liquid cooling system capable of utilizing latent heat of vaporization of a coolant may be applied to an integrated circuit device. The two-phase liquid cooling method may include immersion cooling, spray cooling, and jet impingement cooling.
The immersion cooling is a method of cooling an electronic device to be cooled by immersing the electronic device in a bath containing a liquid coolant. The immersion cooling method is the most widely used method, but because the entire electronic device needs to be immersed in a liquid coolant, the usable coolant is limited to a dielectric coolant. Therefore, the immersion cooling method has several problems such as high management costs and the method is not environmentally friendly. Moreover, when a film boiling phenomenon in which vapor of the coolant is adsorbed to a heating surface occurs, the vapor prevents heat transfer from the heating surface to the coolant, thereby reducing cooling efficiency. In a boiling graph, this phenomenon is called critical heat flux (CHF), and it is necessary to improve the CHF to cool a larger heat flux.
The spray cooling is a method of atomizing a liquid coolant and spraying the coolant on a heating surface and has high cooling efficiency compared to the amount of liquid coolant used. However, a spray cooling device requires a pumping device capable of operating at high pressure and requires continuous maintenance of spray nozzles. The spray cooling also has a problem of lowering cooling efficiency due to a film boiling phenomenon.
The jet impingement cooling is a cooling method in which a liquid coolant is injected to a heating surface at a high speed. Similar to the spray cooling method, the jet impingement cooling method also has high cooling efficiency. However, the jet impingement cooling method has a disadvantage of requiring several injectors to evenly cool the heating surface. Furthermore, even if several injectors are used, there may be a blind area where the jet of liquid coolant does not reach. In addition, the jet impingement cooling also has a problem of a decrease in cooling efficiency due to a film boiling phenomenon.
According to an example embodiment of the disclosure, there is provided a two-phase cooling system including a cooling channel, which is a path for a coolant, in a cooling target. For example, the two-phase cooling system may form a coolant channel in a semiconductor chip. In the cooling channel, a vibrator may be provided. For example, an ultrasonic vibrator applying a vibration to a coolant may be arranged in the cooling channel. In a cooling channel, a liquid coolant may absorb heat from a heat transfer surface adjacent to a heat source and vaporize into vapor. When vapors are attached to the heat transfer surface and become stagnant, due to the film boiling phenomenon, the cooling efficiency may decline, and hot spots may be generated. According to the two-phase cooling system of the disclosure, the ultrasonic vibrator may vibrate the coolant in the cooling channel. The vibration energy of the ultrasonic vibrator may be transmitted to the vapors attached to the heat transfer surface along the coolant, and the vapors may be detached from the heat transfer surface. In this manner, the film boiling phenomenon may be reduced or prevented. As the vibration is applied to the coolant, no damage may be caused to the cooling target, for example, components of the semiconductor chip. According to an embodiment, a linear resonant actuator (LRA) may be employed as the vibrator. According to an embodiment, a micro-machined ultrasonic transducer (MUT) may be employed as the ultrasonic vibrator. The micro-machined ultrasonic transducer may be easily implemented in the semiconductor chip by micro-electron mechanical systems (MEMS) technologies. According to an embodiment, a capillary pattern generating capillary force which moves the liquid coolant may be formed in the cooling channel. As the coolant is moved by the capillary force, in some cases, a coolant supplying member, such as a high-capacity pump, etc. for supplying a coolant to a cooling channel may be omitted, and thus, the prices and power consumption of the cooling system may be reduced. In addition, as the capillary pattern increases a heat transfer area of the heat transfer surface, the heat exchange from a heat source, for example, a semiconductor integrated circuit to the coolant may be facilitated. The capillary pattern may be implemented by an ultrasonic vibrator, for example, a micro-machined ultrasonic vibrator.
In the following description, a first direction (X) denotes one of the directions parallel to an upper surface of the semiconductor chip. A second direction (Z) denotes a thickness direction of the semiconductor chip. A third direction (Y) denotes a direction orthogonal to the first direction (X) among directions parallel to the upper surface of the semiconductor chip.
The semiconductor chip 100 may include a substrate 110 and a semiconductor integrated circuit 120 formed on a surface of the substrate 110. The semiconductor chip 100 may be various semiconductor chips. For example, the semiconductor chip 100 may be a memory die including a memory integrated circuit, a logic die including a logic integrated circuit, a central processing unit (CPU) chip, a graphic processing unit (GPU) chip, an application specific integrated circuit (ASIC) chip, etc. To implement the semiconductor device 1 having a small form factor, the semiconductor chip 100 may be a wafer-level semiconductor integrated circuit chip. In this case, the substrate 110 may be a wafer. The semiconductor chip 100 may be, for example, mounted on a printed circuit board 1000 by a solder ball. A wiring layer 140 for electrically connecting the semiconductor integrated circuit 120 with the printed circuit board 1000 may be arranged under the semiconductor chip 100. The wiring layer 140 may be electrically passivated with respect to the outside.
According to an embodiment, a two-phase liquid cooling structure may include the cooling channel 200. The cooling channel 200 may provide a moving path for a coolant. At least a part of the cooling channel 200 may be formed in the semiconductor chip 100, for example, in the substrate 110. For example, at least a part of the cooling channel 200 may be formed on a surface of the substrate 110 opposite to a surface of the substrate 110 on which the semiconductor integrated circuit 120 is formed. For example, the semiconductor integrated circuit 120 may be formed on a first surface of the substrate 110 and at least a part of the cooling channel 200 may be formed on a second surface of the substrate 110. The cooling channel 200 may be connected to a condenser 800 (or a radiator). For example, the semiconductor chip 100 may be packaged by a package housing 700. The package housing 700 may surround the semiconductor chip 100. In
According to an embodiment, a liquid coolant LC in the cooling channel 200 may absorb a heat from a heat source inside the semiconductor chip 100, for example, the semiconductor integrated circuit 120. The heated liquid coolant LC may be cooled by heat exchange with the outside at the condenser 800 (or radiator) and then supplied to the cooling channel 200. The liquid coolant LC in the cooling channel 200 may be vaporized and become a coolant vapor VC. The coolant vapor VC may be moved to the condenser 800 (or radiator) along the cooling channel 200. The coolant vapor VC may be phase-changed to the liquid coolant LC at the condenser 800 (or radiator), and then the liquid coolant LC may be moved to the inside of the semiconductor chip 100 along the cooling channel 200. According to such structure, the liquid coolant LC may be supplied to a location close to the heat source inside the semiconductor chip 100, which leads to effective cooling of the semiconductor chip 100. Moreover, the semiconductor chip 100 may be effectively cooled by using the evaporative latent heat in the phase change process of the coolant.
According to an embodiment of the disclosure, the semiconductor device 1 may include the ultrasonic vibrator 300. The ultrasonic vibrator 300 may be arranged inside the cooling channel 200. The ultrasonic vibrator 300 may be at least partially immersed in the liquid coolant LC in the cooling channel 200. According to an embodiment, the ultrasonic vibrator 300 may be arranged on the lower surface 201 of the cooling channel 200 and entirely immersed in the liquid coolant LC. According to an embodiment, the ultrasonic vibrator 300 may be arranged closer to the opening 701. However, the disclosure is not limited thereto, and as such, the ultrasonic vibrator 300 may be arranged at any position in the cooling channel 200. The ultrasonic vibrator 300 may vibrate the liquid coolant LC. The vibration energy of the liquid coolant LC may be transmitted to the stagnant vapors 400A or the vapor film 400B in the cooling channel 200 and diminish the adhesion between the lower surface 201 of the cooling channel 200 and the stagnant vapors 400A or the vapor film 400B.
In this manner, an increase in thermal resistance by the stagnant vapors 400A or the vapor film 400B may be reduced or prevented, and thus the cooling performance may remain constant. As the generation of hot spot is prevented or reduced, the heat may be effectively dissipated. As the ultrasonic vibrator 300 is arranged in the cooling channel 200 to vibrate the liquid coolant LC in the cooling channel 200, the stagnant vapors 400A and the vapor film 400B may be effectively removed to improve the cooling efficiency of the two-phase cooling system while not causing any damage to other components of the semiconductor device 1. Although
The ultrasonic vibrator 300 illustrated in
In another embodiment illustrated in
In
The piezoelectric layer 310 may be deformed according to a driving voltage applied to lower electrode layer 320 and the upper electrode layer 330, and ultrasonic waves may be generated. The liquid coolant in the cooling channel 200 may be vibrated by the ultrasonic energy. By this vibration energy, the coolant vapor VC may be separated from the lower surface 201 of the cooling channel 200.
The heat generated at the heat source, i.e., the semiconductor integrated circuit 120 may be transferred to the liquid coolant in the cooling channel 200 through the lower surface 201 of the cooling channel 200, which is a heat transfer surface. Accordingly, the liquid coolant may need to be supplied quickly and sufficiently to the lower surface 201 of the cooling channel 200 without any left-out areas. The capillary pattern 210 may form the capillary force. The liquid coolant in the cooling channel 200 may be effectively moved by the capillary force to the lower surface 201 of the cooling channel 200 on which the capillary pattern 210 is formed and cover the lower surface 201 of the cooling channel 200. The liquid coolant may be phase-changed to vapors near the lower surface 201 of the cooling channel 200 by the heat exchange with the semiconductor integrated circuit 120. The vapors may be moved to other areas of the cooling channel 200 from near the lower surface 201 of the cooling channel 200 by the buoyancy or the vibration energy generated by the ultrasonic vibrator 300. The space the vapors near the lower surface 201 of the cooling channel 200 has left may be filled with the liquid coolant by the capillary force generated by the capillary pattern 210. Accordingly, the area near the lower surface 201 of the cooling channel 200 may be continuously filled with the liquid coolant. In this manner, the liquid coolant may be effectively supplied to the lower surface 201 of the cooling channel 200, which is a heat transfer surface where heat exchange between the semiconductor integrated circuit 120 and the coolant occurs.
The capillary pattern 210 may have various structures capable of forming the capillary force.
With reference to
Various embodiments of the capillary pattern 210 illustrated in
Referring back to
The capillary pattern 210 may be implemented by a plurality of ultrasonic vibrators 300. That is, the plurality of ultrasonic vibrators 300 may form the capillary pattern 210 moving the coolant by the capillary force in the cooling channel 200.
The plurality of ultrasonic vibrators 300 may form a part of the capillary pattern 210. For example, a part of the capillary pattern 210 may be formed by the plurality of ultrasonic vibrators 300 in the embodiments of the capillary pattern 210 illustrated in
According to the high integration and high performance of the semiconductor device 1, a plurality of semiconductor chips 100 may be stacked. The semiconductor device 1 having such stacked structure may be referred to as a 3D IC. In the semiconductor device 1 having a stacked structure, as a plurality of semiconductor chips 100 are stacked closely, an effective two-phase cooling structure may be required. The aforementioned two-phase cooling structure may be employed in the semiconductor device 1 having such structure.
The first semiconductor chip 100-1 may be, for example, mounted on the printed circuit board 1000 by a solder ball. The second semiconductor chip 100-2 may be electrically connected with the printed circuit board 1000 directly, and may be electrically connected with the printed circuit board 1000 via the first semiconductor chip 100-1. In the embodiment, the second semiconductor chip 100-2 may be electrically connected with the printed circuit board 1000 via the first semiconductor chip 100-1 by an electrical connection structure 500, for example, a through silicon via (TSV). A portion of the electrical connection structure 500 exposed to the outside of the first and second semiconductor chips 100-1 and 100-2 may be electrically passivated.
The first and second semiconductor chips 100-1 and 100-2 may be packaged by the package housing 700. The packaging housing 700 may surround the first and second semiconductor chips 100-1 and 100-2. The opening 701 connected with a second cooling channel 200 of the second semiconductor chip 100-2 may be provided in the package housing 700. The coolant may be moved to the cooling channel 200 and the connection channel 250 of the second semiconductor chip 100-2 through the opening 701. The coolant may be moved to the cooling channel 200 of the first semiconductor chip 100-1 through the connection channel 250. Although FIG. 13 illustrates that a gap 400 is formed between the first and second semiconductor chips 100-1 and 100-2, the first and second semiconductor chips 100-1 and 100-2 may be stacked without the gap 400. In this case, the connection channel 250 of the second semiconductor chip 100-2 and the cooling channel 200 of the first semiconductor chip 100-1 may be arranged in the longitudinal direction, i.e., the second direction (Z).
The liquid coolant may be supplied to the cooling channel 200 arranged in the first and second semiconductor chips 100-1 and 100-2. The liquid coolant may absorb heat from a heat source of the first and second semiconductor chips 100-1 and 100-2, for example, the semiconductor integrated circuit 120 and may be vaporized into vapors. The vapors stagnant or attached on a wall of a cooling channel 200 may be detached from the wall of the cooling channel 200 by the vibration energy of the ultrasonic vibrator 300 and may be moved to the outside of the cooling channel 200. The vapors may be phase-changed to a liquid coolant at the condenser 800 and then may be moved back to the cooling channel 200. According to such structure, the liquid coolant may be supplied close to the heat source in the stacked first and second semiconductor chips 100-1 and 100-2, which leads to effective cooling of the first and second semiconductor chips 100-1 and 100-2.
According to an embodiment, three or more semiconductor chips 100 may be stacked in the thickness direction, i.e., the second direction (Z). According to an embodiment, another semiconductor chip which does not employ a cooling structure may be arranged on the printed circuit board 1000. For example, the other semiconductor chip that does not employ a cooling structure may be packaged by a separate housing, or may be packaged along with the semiconductor chip 100 employing a cooling structure in one housing. The other semiconductor chip without a cooling structure may be sealed to avoid a contact with the coolant. According to an embodiment, a plurality of semiconductor chips may be arranged in the transverse direction. For example, in the embodiments of the semiconductor device 1 illustrated in
According to the embodiments of a semiconductor device, by vibrating a coolant in a cooling channel by using an ultrasonic vibrator, stagnant vapors and/or vapor film may be reduced or removed. Accordingly, generation of hot spot may be reduced and prevented, and a semiconductor device having a two-phase cooling structure with improved cooling efficiency may be implemented.
It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0179736 | Dec 2022 | KR | national |
