Thermoelectric Cooling in Microelectronics

Abstract

In some aspects, the disclosed technology provides a microelectronic device that efficiently dissipates heat and manages hot spots. In some embodiments, the disclosed microelectronic device includes a substrate having a thickness in a first direction and at least one thermoelectric unit disposed in or on the substrate. The thermoelectric unit may be configured to transfer heat along a second lateral direction orthogonal to the first direction.

Description

[Technical field]

[0001] The technical field relates to heat dissipation and hot spot management in microelectronics.

[0002] [Citation to Related Applications] This application claims priority to U.S. Provisional Patent Application No. 63 / 265,770, filed on December 20, 2021 (title: THERMOELECTRIC COOLING IN MICROELECTRONICS), which is incorporated by reference in its entirety. [Background technology]

[0003] The miniaturization and high density integration of electronic components increases the heat flux density of microelectronics. Microelectronic components typically operate below a certain rated temperature to ensure optimal operation. If the heat generated during the operation of microelectronics is not sufficiently dissipated, distributed, or drawn off, the microelectronics cannot operate reliably, its performance will be affected, and it may even shut down or burn out. In particular, heat dissipation is a serious challenge in high power devices, and this challenge is further exacerbated with chip stacking. Summary of the Invention

[0004] In one aspect, the disclosed technology provides a microelectronic device that efficiently dissipates heat and manages hot spots. In some embodiments, the disclosed microelectronic device includes a substrate having a thickness in a first direction and at least one thermoelectric unit disposed in or on the substrate. The thermoelectric unit may be configured to transfer heat along a second lateral direction orthogonal to the first direction.

[0005] Specific embodiments will now be described with reference to the following drawings, which are provided by way of illustration and not by way of limitation of the invention. [Brief description of the drawings]

[0006] [Figure 1A] FIG. 1 illustrates a schematic diagram of an exemplary microelectronic system of the disclosed technology. [Figure 1B] FIG. 1 illustrates a schematic diagram of an exemplary microelectronic system of the disclosed technology. [Figure 1C] FIG. 1 illustrates a schematic diagram of an exemplary microelectronic system of the disclosed technology. [Diagram 2] FIG. 2 is a schematic diagram of another exemplary microelectronic system of the disclosed technology. [Figure 3A] FIG. 13 is a diagram illustrating a schematic diagram of another thermoelectric unit according to an embodiment of the disclosed technology. [Figure 3B] FIG. 13 is a schematic diagram of another thermoelectric unit according to another embodiment of the disclosed technology. [Figure 4] FIG. 2 is a schematic cross-sectional view of yet another exemplary microelectronic device of the disclosed technology. [Diagram 5] FIG. 2 is a schematic cross-sectional view of yet another exemplary microelectronic device of the disclosed technology. [Figure 6A] 1 is a diagram illustrating a schematic configuration example of a thermoelectric unit of the disclosed technology. [Figure 6B] 11 is a diagram illustrating a schematic configuration example of a thermoelectric unit of the disclosed technology. FIG. [Figure 6C] 11 is a diagram illustrating a schematic configuration example of a thermoelectric unit of the disclosed technology. FIG. [Figure 6D] 11 is a diagram illustrating a schematic configuration example of a thermoelectric unit of the disclosed technology. FIG. [Figure 7] FIG. 2 illustrates an example control circuit for controlling a thermoelectric unit of the disclosed technology. [Figure 8A] FIG. 1 illustrates stacked thermoelectric elements in an exemplary chip stack. [Figure 8B]FIG. 13 shows stacked thermoelectric elements in another exemplary chip stack. [Figure 8C] 1 is a diagram illustrating a schematic configuration example of a thermoelectric unit of the disclosed technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Microelectronic elements (e.g., dies / chips) can be stacked and bonded together to form a device. Dissipating heat from the device with chip stacking is difficult, especially as the chips are becoming thinner. The use of chip attachment methods, such as adhesive bonding, flip chip interconnection, etc., can result in less efficient heat dissipation or heat transfer to a heat sink or final drawer within the device, as the adhesive can reduce or block heat transfer. Furthermore, it is difficult to specifically lower the temperature of a desired portion of the device. For example, when packaging a stack of dies, heat dissipation is typically aided by a heat sink at the top of the stack, but it is difficult to extract heat from the lower die. Furthermore, given the dimensions of a typical die or die stack, the vertical path length is quite short compared to the lateral path length for heat extraction purposes. However, embodiments that only provide vertical heat transfer capture the heat of the bottom or middle die, which can result in these dies becoming quite hot, effectively limiting stacking implementation to low power chips. Thus, there is a continuing need for improved techniques for dissipating heat in microelectronic devices.

[0008] Methods and structures are provided to redirect heat flow in a die stack, for example, redirecting heat from a central location on the die to the periphery of the die or die stack from which the heat can be extracted to a heat dissipation structure (e.g., heat sink / heat pipe), or redirect heat from one location (e.g., a hot spot) on the die to another, or spread the hot spot over a larger area, or redirect heat from the lower die to a heat sink without increasing the temperature of any intervening die. In some embodiments, the disclosed microelectronic device 100 may have a thermoelectric element 103 that directs heat laterally (as indicated by the left and right arrows) to the die / chip 101 or 102 (i.e., along the long dimension of the die) as shown in FIG. 1A. In some embodiments, the microelectronic device 100 disclosed in Figure 1A can utilize a thermoelectric element 103 having multiple cascaded thermoelectric units, e.g., thermoelectric units 1030, 1031, 1032, to transfer heat laterally from a lower die (e.g., 101) in the device 100 to the periphery of the device 100, as shown in Figure 1B. For example, the cascaded thermoelectric units, e.g., thermoelectric units 1030, 1031, 1032, can be disposed in (or on) a substrate (not shown). The substrate can have a smallest dimension along a first direction (e.g., z-direction), where the smallest dimension can comprise the thickness of the substrate. In some embodiments, the cascaded thermoelectric units, e.g., thermoelectric units 1030, 1031, 1032, may include a Peltier element having an N-doped region or a P-doped region formed in a substrate, e.g., a thermoelectric substrate (e.g., Bi2Te3), as described in U.S. Provisional Patent Application No. 63 / 265,765, filed Dec. 20, 2021, entitled THERMOELECTRIC COOLING FOR DIE PACKAGES, which is incorporated by reference in its entirety. In some embodiments, the thickness is 100 microns or less, preferably 50 microns or less. The thermoelectric unit 103 may be configured to transfer heat along a second lateral direction (e.g., x-direction) perpendicular to the first direction.The thermoelectric element 103 can actively redirect heat flow within the device 100 by drawing heat away from the device 100, for example, to help actively reduce the temperature of a particular chip or a particular hot spot in the chip within the device. The thermoelectric element 103 can be a Peltier element that includes two materials with different Peltier coefficients joined together at a junction. The Peltier element can utilize the Peltier effect to create a net heat flux at the junction of two different materials when electrical energy (e.g., DC current) is provided due to an imbalance of Peltier heat flowing in and out of the junction. In some embodiments, the Peltier element can include multiple pairs of p-type and n-type semiconductor pellets, elements, or chips that are electrically connected in series (e.g., p-type and n-type semiconductor pellets in the thermoelectric unit 1031 are coupled together by electrical connections 1081) and thermally coupled in parallel, so that all charge carriers and heat can flow through the pellets in the same direction.

[0009] In some embodiments, the thermoelectric element 103 is not bonded to other elements of the device 100 by adhesives or thermally conductive materials (TIMs) that may impede heat transfer. Rather, the thermoelectric element 103 may be directly bonded to another element in the device 100, thus improving heat transfer efficiency. For example, a plurality of p-type and n-type semiconductor pellet pairs may be directly bonded to the active chip (e.g., 101 or 102). In some embodiments, the thermoelectric element 103 may be directly hybrid bonded to another element, such that the conductive contacts and insulating layers are directly bonded to corresponding conductive contacts and insulating layers of the other element. In other embodiments, the thermoelectric element 103 may be directly bonded to the other element with only a direct insulator-to-insulator (sometimes referred to as insulator-to-insulator) bond. The active chip (e.g., 101 or 102) may be a die having active circuitry, e.g., the active circuitry may include one or more transistors.

[0010] In some embodiments, the multiple p-type and n-type semiconductor thermoelectric pellet pairs may be divided into many groups (e.g., 1030, 1031, 1032) and each group may be controlled independently. For example, a sensor (e.g., a diode) may be used to measure the temperature at a location in the device. If the temperature at that location is higher than a threshold, the group of thermoelectric pellets or element pairs (e.g., 1031) associated with that location may be activated by passing a current through a pair of electrical contact pins / pads 1091 (e.g., each of the electrical contact pins / pads may have a voltage of +V or V applied to it). In this way, the temperature in the device may be locally monitored and controlled. Also, the ability to operate each group of thermoelectric pellet pairs (e.g., 1030, 1031, 1032) independently may reduce the power consumption of the thermoelectric element 103. The thermoelectric element 103 may be configured to enable zone cooling control and localized heat dissipation in response to a measured hot spot distribution of the chip. In various embodiments, a signal measured by a temperature sensor may be used to control the thermoelectric element 103, which may be located in the active chip to be cooled (e.g., 101 or 102) or may be located in the thermoelectric element 103. In various embodiments, the thermoelectric element 103 may be controlled by the active chip to be cooled (e.g., 101 or 102) in the thermoelectric element 103 or by an external chip on the system board.

[0011] 1B is a schematic isometric view of a portion of the exemplary microelectronic device 100 shown in FIG. 1A, including a lower carrier 101 (which may comprise a die / chip, wafer, interposer, or other suitable element) and a thermoelectric element 103 arranged in a manner that allows heat to be directed laterally relative to the lower element 101. For example, charge carriers may move from hot plates (1021, 1005, respectively) in the XY and YZ planes to a cold plate (1007) in the YZ plane, and as heat is extracted and moves in one direction, they may bend / turn to change direction to obtain a horizontal distribution of thermal energy. In other words, charge carriers moving from the hot plate (1005) in the YZ plane to the cold plate (1007) in the YZ plane spread heat away from the hot spot (1021) in the XY plane, thereby effectively spreading out the hot spot and reducing its peak temperature. The thermoelectric device 103 may be operated by an exemplary control circuit as shown in Figure 1C. In one embodiment, the thermoelectric device 103 may include multiple thermoelectric units, such as thermoelectric units 1030, 1031, 1032 (e.g., disposed / formed in a Bi2Te3 wafer), where unit 1031 (e.g., including a pair of p-type and n-type semiconductor Peltier pellets) may collect heat from the left unit 1030 (or right unit 1032 depending on where the hot spot is located) and the bottom chip 101 (or top chip 102, as the case may be) and deliver this heat to the cold plate surface 1007 to the right (or left depending on the direction of current provided to the thermoelectric unit or pair). In various embodiments, the thermoelectric units, e.g., thermoelectric units 1030, 1031, 1032, may be arranged as an X-Y matrix, radially or in any other suitable uniform (periodic) or non-uniform distribution based on a thermal map provided during actual experiments or thermal simulations on the chip or chip stack.

[0012] FIG. 2 illustrates an example microelectronic device 200 similar to the microelectronic device illustrated in FIGS. 1A and 1B, where like features are indicated with like reference numerals, and where each thermoelectric unit (e.g., 1030, 1031, 1032) can direct heat in both directions depending on the polarity of the applied voltage bias. In the embodiment illustrated in FIG. 2, a thermally conductive but electrically insulating plate 2070 (e.g., made of TiN, aluminum nitride, etc.) can be provided between two adjacent thermoelectric units (e.g., between 1030 and 1031 and / or between 1031 and 1032) to enhance the heat transfer between the two adjacent thermoelectric units while preventing electrical conduction or leakage of current between the two adjacent thermoelectric units. Although FIG. 2 illustrates the plate 2070 and the thermoelectric units in an exploded view, in practice, there may be no gap between the plate 2070 and its adjacent thermoelectric units.

[0013] 3A and 3B show an example thermoelectric unit similar to that shown in FIG. 1B, with like features being indicated with like reference numbers. However, as shown in FIG. 3A, in some embodiments of the thermoelectric unit 3031A, separate electrodes (e.g., 3091, 3092) for the vertical and horizontal hot plates (1005, 1021) can effectively affect the direction of charge carrier flow between one or both hot plates (1005 and / or 1021) and the cold plate 1007. This allows heat extraction to move laterally from the bottom or only laterally (i.e., without any direct active extraction from the bottom). In some embodiments, the separate electrodes (e.g., 3091, 3092 at the top and bottom faces, respectively) can be separate and independent from each other, and the use of these separate electrodes can optimize heat flow. For example, the voltages applied to the electrodes 3091, 3092 can all be different from each other. 3B, in some embodiments of the thermoelectric unit 3031B, interconnected electrodes (e.g., 3099) at the top and bottom surfaces (1005, 1021) of the thermoelectric unit 3031B allow heat extraction from both the top and side surfaces of the thermoelectric unit 3031B because the interconnected electrodes 3099 direct the charge carrier flow towards the cold plate 1007. For example, the overall charge carrier flow may be oblique to the pellet of the thermoelectric unit 3031B.

[0014] FIG. 4 is a schematic cross-sectional view of an example microelectronic device 400 having stacked dies and a thermoelectric element 403 (described in connection with any of the previous figures) that directs heat laterally from a bottom chip (401). In some embodiments, the thermoelectric element 403 may include a Peltier element embedded in a substrate, such as a thermoelectric substrate (e.g., Bi2Te3). The Peltier element may include an N-doped or P-doped region formed in a substrate, such as described in U.S. Provisional Patent Application No. 63 / 265,765, filed Dec. 20, 2021, entitled THERMOELECTRIC COOLING FOR DIE PACKAGES, which is incorporated by reference in its entirety. A thermal pathway 467, or thermally conductive block, may dissipate heat from the thermoelectric element 403 to a heat sink 405 at the top of the die stack. The microelectronic device 400 may further include several other chips (e.g., 4001, 4002) that are thermally insulated from the bottom chip (401). The thermoelectric element 403 may be powered by electrical contacts that connect to the bottom chip 401, such as electrical contacts that couple to through-substrate vias in the bottom chip 401. In some embodiments, the bottom chip 401 may be in electrical communication with chips 4001 and / or 4002 by through-substrate vias. In some examples, heat flow may be directed laterally from a central or inner portion of any of the bottom chips 401, 4001, and 4002 to thermal paths 467 that redirect the heat vertically to the heat sink 405. In some embodiments, the thermoelectric element 403 may be direct hybrid bonded to another element such that the conductive contacts and insulating layers are direct bonded to corresponding conductive contacts and insulating layers of the other element. In other embodiments, the thermoelectric element 403 may be directly bonded to other elements with only direct insulator-to-insulator bonds.

[0015] 5 is a schematic cross-sectional view of an example microelectronic device 500 having stacked chips and thermoelectric elements 5031, 5032, 5033 that direct heat laterally at one or multiple layers of the device 500. Thermal paths 567, or thermally conductive blocks, can dissipate heat from the thermoelectric elements 5033 to a heat sink 505 at the periphery of the device 500. In some embodiments, cascaded thermoelectric units 5031, 5032, 5033 dissipate heat to the edge of the chip (e.g., 5011, 5012, 5013, 5014, 5015) for extraction (e.g., by side / edge extraction with a heat sink 505 or heat spreader, or vertical extraction with an exposed surface). In some embodiments, such thermoelectric elements 5031, 5032, 5033 can distribute / diffuse / dissipate heat spots, thereby reducing the impact of heat spots on device performance by reducing peak temperatures. In some embodiments, such thermoelectric elements 5031, 5032, 5033 can be used to enable thermal management within an area that is small compared to the entire chip, for example, to transport heat from one location to another, or to distribute or diffuse hot spots over a large area. In some embodiments, the thermoelectric elements 5031, 5032, 5033 can be direct hybrid bonded to another element, such that the conductive contacts and insulating layers are directly bonded to corresponding conductive contacts and insulating layers of the other element. In other embodiments, the thermoelectric elements 5031, 5032, 5033 can be directly bonded to the other element with only direct insulator-to-insulator bonds.

[0016] In some embodiments, hot spots in the die may be managed by temperature sensors (e.g., 698) built into the die or part of the thermoelectric elements 603 to detect hot spots and create a thermal map. In such embodiments, the thermoelectric units 603 may be arranged in various patterns to direct heat flow in a specific direction optimized by the controller based on the thermal map. For example, the thermoelectric units 603 may be arranged in a grid as shown in FIG. 6A or FIG. 6B, or radially as shown in FIG. 6C, which may dissipate heat laterally to the bottom die. Any other suitable uniform / periodic or non-uniform distribution of thermoelectric elements may also be arranged. This arrangement may be based on actual thermal maps or thermal simulations from the example device. The thermoelectric units 603 may be powered through conductive vias in the bottom die, or may be powered separately by an external chip. FIG. 6D is a plan view of thermoelectric units 603 arranged in a plane perpendicular to the thickness direction of a wafer in which the thermoelectric units 603 are housed and associated with electrical contacts for position control and optimization of heat dissipation. In some embodiments, the thickness is 100 microns or less, preferably 50 microns or less. In some examples, the thermoelectric units 603 shown in FIG. 6D are configured to transfer heat along a path in the plane of the thermoelectric units 603, the path including at least one turn in the plane. Although the thermoelectric units are shown in FIG. 6D to transfer heat in the XY plane along the XX or YY direction (indicated by the arrows), the thermoelectric units may be arranged in other directions, as shown in FIG. 8C.

[0017] FIG. 7 illustrates an example control circuit / logic 700 for controlling thermoelectric units 703 and heat dissipation in the disclosed device as described in connection with any of the previous figures. The disclosed control circuit 700 can turn on the units 703 one after the other with a small delay to drive heat flow. The control circuit 700 can also activate the units 703 in any suitable optimized pattern (by location or time) for efficient heat distribution in some embodiments. The disclosed control circuit 700 can monitor the heat map of the die (e.g., using thermal sensors located inside or outside the thermoelectric element or embedded in the chip) and drive heat flow by activating one or more groups or zones of thermoelectric units 703 or pairs, and can improve heat dissipation / distribution by driving heat flow towards one or more optimal locations. In some embodiments, all the thermoelectric units 703 can be coupled in parallel with each other, thus independently managing temperature control of different locations on a die. In some embodiments, the disclosed devices may include a combination of several thermoelectric elements 703 coupled together in parallel to form a block, and then several such blocks are connected together in series. In other embodiments, the disclosed devices may include a combination of several thermoelectric elements 703 coupled together in series to form a block, and then several such blocks are connected together in parallel. Any suitable distribution and combination of thermoelectric elements 703 may be arranged. In some embodiments, a separate controller chip may be part of the device chip stack.

[0018] FIG. 8A shows stacked thermoelectric elements in a chip stack 800A (e.g., including a top die 802 and a bottom die 801). Heat can be extracted upwards, in some cases, as indicated by the arrows, through another layer of thermoelectric elements 8035 stacked on top of a layer of laterally cascaded thermoelectric units 803 around the extremely hot spots. FIG. 8B shows a chip stack 800B (e.g., including a top die 802 and a bottom die 801) that includes thermoelectric units arranged in a manner that allows for heat extraction in both lateral and vertical directions. For example, several thermoelectric units 8035 that can extract heat upwards (or downwards), as indicated by the arrows, can be embedded within a layer of laterally cascaded thermoelectric units 803. In some embodiments, the disclosed devices can further include a thermal barrier / insulator layer to shield heat from traveling to the top die 802. In some embodiments, the thermoelectric elements 803, 8035 may be direct hybrid bonded to another element such that the conductive contacts and insulating layers are directly bonded to corresponding conductive contacts and insulating layers of the other element, while in other embodiments, the thermoelectric elements 803, 8035 may be directly bonded to the other element with only direct insulator-to-insulator bonds.

[0019] Electronic Devices The semiconductor device may include, for example, an integrated device die of any suitable type. For example, the integrated device die may include electronic components, such as integrated circuits (e.g., a processor die, a controller die, or a memory die), a microelectromechanical system (MEMS) die, an optical device, or any other suitable type of device die. In some embodiments, the electronic components include passive devices, such as capacitors, inductors, or other surface mount devices. Circuitry (e.g., active components such as transistors) may be patterned at or near the active side in various embodiments. The active side may be located on a side of the die opposite the back side of the die (front side). The back side may or may not include any active or passive circuitry.

[0020] The integrated device die may have a bonding surface and a back surface opposite the bonding surface (in this case, the "front surface"). The bonding surface may have a plurality of conductive bond pads including one conductive bond pad, and a non-conductive material located proximate the conductive bond pads. In some embodiments, the conductive bond pads of the integrated device die may be directly bonded to corresponding conductive pads of the substrate or wafer without an intervening adhesive, and the non-conductive material of the integrated device die may be directly bonded to a portion of the corresponding non-conductive material of the substrate or wafer without an intervening adhesive. Direct bonding without adhesives is described in U.S. Patent Nos. 7,126,212, 8,153,505, 7,622,324, 7,602,070, 8,163,373, 8,389,378, 7,485,968, 8,735,219, 9,385,024, 9,391,143, and 9,4 Nos. 31,368, 9,953,941, 9,716,033, 9,852,988, 10,032,068, 10,204,893, 10,434,749, and 10,446,532, each of which is incorporated by reference in its entirety and incorporated herein for all purposes.

[0021] Direct bonding method and direct bonded structure Various embodiments disclosed herein relate to a direct bonded structure in which two elements can be directly bonded without an intervening adhesive. The two or more electronic elements can be semiconductor elements (e.g., integrated device dies, wafers, etc.), and the two or more electronic elements can be stacked or bonded together to form a bonded structure. The conductive contact pads of one element can be electrically connected to the corresponding conductive contact pads of the other element. Any suitable number of elements can be stacked into a bonded structure. The contact pads can be metal pads formed on non-conductive bonding areas, and can be connected to an underlying metallization, such as a redistribution layer (RDL).

[0022] In some embodiments, the elements are directly bonded to each other without adhesive. In various embodiments, a non-conductive material or dielectric of a first element may be directly bonded to a corresponding non-conductive or dielectric field region of a second element without adhesive. The non-conductive material may be referred to as a non-conductive bonding region or bonding layer of the first element. In some embodiments, the non-conductive material of a first element may be directly bonded to a corresponding non-conductive material of a second element using inter-dielectric bonding techniques. For example, inter-dielectric bonds may be formed without adhesive using direct bonding techniques as disclosed in at least U.S. Patent Nos. 9,564,414, 9,391,143, and 10,434,749, each of which is incorporated by reference herein in its entirety for all purposes. Dielectrics suitable for direct bonding include, but are not limited to, inorganic dielectrics such as silicon oxide, silicon nitride, silicon oxynitride, or carbon such as silicon carbide, silicon oxycarbonitride, silicon carbonitride, or diamond-like carbon. In some embodiments, the dielectric does not include a polymeric material such as an epoxy, resin, or molding compound.

[0023] In some embodiments, the direct hybrid bond can be formed without an intervening adhesive. For example, the dielectric bonding surfaces can be polished to a high degree of smoothness. The bonding surfaces can be cleaned and exposed to a plasma and / or an etchant to activate the surfaces. In some embodiments, the surfaces can be terminated with a chemical species after or during activation (e.g., during a plasma and / or etch process). Without being bound by theory, in some embodiments, the activation process can be performed to break chemical bonds at the bonding surfaces, and the end-grouping process can provide additional chemical species at the bonding surfaces that improve the bonding energy during direct bonding. In some embodiments, activation and end-grouping can be provided in the same step, for example, the surfaces can be activated and end-grouped using a plasma or a wet etchant. In other embodiments, the bonding surfaces can be end-grouped in a separate process to provide additional chemical species that can be used for direct bonding. In various embodiments, the end-grouping chemical species can include nitrogen. For example, in some embodiments, the bonding surfaces can be exposed to fluorine. For example, one or many fluorine peaks may appear near the layers and / or bonding interface. Thus, in a direct bonded structure, the bonding interface between the two dielectrics may comprise a very smooth interface with high nitrogen content and / or fluorine peaks at the bonding interface. Additional examples of activation and / or end group treatments can be found throughout U.S. Patent Nos. 9,564,414, 9,391,143, and 10,434,749, each of which is incorporated by reference and incorporated herein in its entirety for all purposes.

[0024] In various embodiments, the contact pads of the first component may also be directly bonded to the corresponding conductive contact pads of the second component. For example, hybrid direct bonding techniques may be used to provide conductor-conductor direct bonds along a bond interface that includes a covalently directly bonded inter-dielectric surface that has been pretreated as described above. In various embodiments, conductor-conductor (e.g., contact pad-contact pad) direct bonds and dielectric-dielectric hybrid bonds may be formed using direct bonding techniques as disclosed at least in U.S. Patent Nos. 9,716,033 and 9,852,988, each of which is incorporated by reference herein in its entirety for all purposes.

[0025] For example, the dielectric bonding surfaces may be pretreated and directly bonded to each other without an intervening adhesive as described above. The conductive contact pads, which may be surrounded by a non-conductive dielectric field region, may also be directly bonded to each other without an intervening adhesive. In some embodiments, the contact pads may be recessed below the dielectric field region or the outer surface (e.g., top surface) of the non-conductive bonding layer, for example by less than 30 nm, less than 20 nm, less than 15 nm, or less than 10 nm, for example, in the range of 2 nm to 20 nm or in the range of 4 nm to 10 nm. The non-conductive bonding layers may in some embodiments be directly bonded to each other without an adhesive at room temperature with a bonding tool described herein, after which the bonded structure may be annealed. The annealing may be performed in a separate apparatus. During annealing, the contact pads may expand and contact each other, thereby forming a metal-metal (intermetal) direct bond. Advantageously, the use of hybrid bonding technology, such as Direct Bond Interconnect, or DBI® technology, commercially available from Adair, Inc., San Jose, Calif., allows for a high density of pads connected across the direct bond interface (e.g., with a small or fine pitch for a regular array). In some embodiments, the pitch of the bond pads, or the conductive traces embedded in the bonding surface of one of the bonded elements, may be less than 40 microns, or less than 10 microns, or even less than 2 microns. For some applications, the ratio of the bond pad pitch to one of the bond pad features is less than 5 or less than 3, and in some cases desirably less than 2. In other applications, the width of the conductive traces embedded in the bonding surface of one of the bonded elements may range from 0.3 microns to 5 microns. In various embodiments, the contact pads and / or traces may be made of copper, although other metals may be suitable.

[0026] Thus, in a direct bonding process, the first element can be directly bonded to the second element without an intervening adhesive. In some configurations, the first element can be a singulated element, such as a singulated integrated device die. In other configurations, the first element can be a carrier or substrate (e.g., a wafer) that includes multiple (e.g., tens, hundreds, or more) device regions that, when singulated, form multiple integrated device dies. In the embodiments described herein, the first element, whether a die or a substrate, may be considered a host substrate, which is attached to a support of a bonding tool for pick-and-placement of the second element or for receiving a robotic end effector. The second element in the illustrated embodiment is a die. In other configurations, the second element can be a carrier or flat panel, or a substrate (e.g., a wafer).

[0027] As described herein, the first and second elements can be directly bonded together without adhesive, which is different from a deposition process. In one application, the width of the first element in the bonded structure can be approximately the same as the width of the second element. In some other embodiments, the width of the first element in the bonded structure can be different from the width of the second element. The width or area of ​​the larger element in the bonded structure can be at least 10% larger than the width or area of ​​the smaller element. Thus, the first and second elements can be comprised of non-deposited elements. Furthermore, unlike deposited layers, the direct bonded structure can include defect areas along the bond interface where nanocavities exist. The nanocavities can form due to activation (e.g., exposure to plasma) of the bonding surface. As discussed above, the bond interface can exhibit a concentration of material resulting from activation and / or final chemical treatment processes. For example, in embodiments utilizing nitrogen plasma for activation, a nitrogen peak can form at the bond interface. In embodiments utilizing oxygen plasma for activation, oxygen peaks may form at the bond interface. In some embodiments, the bond interface may be comprised of silicon oxynitride, silicon oxycarbonitride, or silicon carbonitride. As described herein, the direct bond may include a covalent bond, which is stronger than a van der Waals bond. The bonding layer may further have a polished surface that is planarized to a high degree of smoothness. For example, the bonding layer may have a surface roughness of 2 nm root mean square (RMS) per micron or 1 nm RMS per micron.

[0028] In various embodiments, the metal-metal bonds between the contact pads in the direct hybrid bonded structure may be bonded such that the conductive feature grains on the conductive features, e.g., copper grains, grow into one another across the bond interface. In some embodiments, the copper may have grains oriented along 111 crystal planes to improve diffusion of the copper across the bond interface. The bond interface may extend substantially completely to at least a portion of the bonded contact pad, such that there are substantially no gaps between the non-conductive bond regions at or near the bonded contact pad. In some embodiments, a barrier layer may be provided under the contact pad (e.g., which may include copper). However, in other embodiments, there may not be a barrier layer under the contact pad, as described, for example, in U.S. Patent Application Publication No. 2019 / 0096741, which is incorporated by reference in its entirety and is hereby incorporated by reference for all purposes.

[0029] In one aspect, the disclosed technology relates to a microelectronic device comprising a substrate having a thickness in a first direction and at least one thermoelectric unit disposed within the substrate, the thermoelectric unit configured to transfer heat along a second lateral direction perpendicular to the first direction. In one embodiment, the substrate is directly bonded (e.g., direct hybrid bonded) to a semiconductor device. In one embodiment, the substrate has a surface configured for direct hybrid bonding. In one embodiment, the substrate further has an opposing surface configured for direct hybrid bonding. In one embodiment, at least one additional thermoelectric unit is disposed within the substrate, the at least one additional thermoelectric unit configured to transfer heat along the second direction. In one embodiment, a thermally conductive plate is disposed between the at least one thermoelectric unit and the at least one additional thermoelectric unit. In one embodiment, the thermally conductive plate is electrically insulating. In one embodiment, the at least one thermoelectric unit is disposed within the substrate.

[0030] In one embodiment, at least one additional thermoelectric unit is disposed within the substrate, the at least one additional thermoelectric unit configured to transfer heat along a second direction and a third direction non-parallel to the first direction. In one embodiment, a thermally conductive plate is disposed between the at least one thermoelectric unit and the at least one additional thermoelectric unit. The thermally conductive plate is electrically insulating. In one embodiment, at least one additional thermoelectric unit is disposed within the substrate, the at least one additional thermoelectric unit configured to transfer heat along the first direction. In one embodiment, a thermally conductive plate is disposed between the at least one thermoelectric unit and the at least one additional thermoelectric unit. In one embodiment, the thermally conductive plate is electrically insulating. In one embodiment, the thickness is 100 microns or less. In one embodiment, the thermoelectric unit is further configured to transfer heat in the first direction. In one embodiment, the thermoelectric unit is associated with a pair of electrical contacts configured to direct electrical current through the thermoelectric unit along both a first direction and / or a second direction, hi one embodiment, the thermoelectric unit is associated with two pairs of electrical contacts, each pair of electrical contacts configured to direct electrical current through the thermoelectric unit along one of the first direction and the second direction.

[0031] In another aspect, the disclosed technology relates to a microelectronic device comprising a substrate having a thickness in a first direction and at least one thermoelectric unit disposed within the substrate, the thermoelectric unit configured to radially transfer heat in a plane perpendicular to the first direction. In one embodiment, the substrate is directly bonded (e.g., direct hybrid bonded) to a semiconductor device. In one embodiment, the substrate has a surface configured for direct hybrid bonding. In one embodiment, the substrate further has an opposing surface configured for direct hybrid bonding. In one embodiment, the thickness is 100 microns or less. In one embodiment, at least one additional thermoelectric unit is disposed within the substrate, the at least one additional thermoelectric unit configured to transfer heat along the first direction, along a second direction perpendicular to the first direction, or along a third direction non-parallel to the second and first directions. In one embodiment, a thermally conductive structure is disposed between the at least one thermoelectric unit and the at least one additional thermoelectric unit. In one embodiment, the thermally conductive structure is electrically insulating.In one embodiment, at least one thermoelectric unit is disposed within the substrate.

[0032] In another aspect, the disclosed technology relates to a microelectronic device, the microelectronic device comprising a lower semiconductor element and a substrate disposed on the lower semiconductor element, the substrate having a thickness in a first direction, the microelectronic device further comprising at least one thermoelectric unit disposed in or on the substrate, the thermoelectric unit configured to transfer heat laterally at least along a second direction perpendicular to the first direction. In one embodiment, the thermoelectric units are configured to transfer heat along a path in a plane perpendicular to the first direction, the path including at least one turn in the plane. In one embodiment, the thermoelectric unit is configured to transfer heat bidirectionally along the second direction. In one embodiment, the thermoelectric unit is configured to transfer heat radially in a plane perpendicular to the first direction. In one embodiment, the thermoelectric unit is configured to transfer heat along a third direction non-parallel to the second direction and the first direction. In one embodiment, the substrate is directly bonded to the semiconductor element without adhesive. In one embodiment, the semiconductor device is made of silicon, ceramic, silicon carbide, gallium nitride, or glass. In one embodiment, the semiconductor device is free of active circuitry. In one embodiment, the at least one thermoelectric unit is disposed within a substrate.

[0033] In one embodiment, the semiconductor device includes an integrated device die with active circuitry. In one embodiment, the interface between the semiconductor device and the substrate includes a conductor-to-conductor direct bond. In one embodiment, the interface between the semiconductor device and the substrate further includes a non-conductor-to-non-conductor direct bond. In one embodiment, a heat sink is attached to at least the substrate. In one embodiment, during operation of the thermoelectric unit, heat is dissipated from the substrate to the heat sink. In one embodiment, a thermally conductive element is provided between the substrate and the heat sink. In one embodiment, the thermally conductive element is free of active circuitry. In one embodiment, the thermally conductive element is made of silicon or ceramic. In one embodiment, the substrate is directly bonded to the thermally conductive element without an adhesive. In one embodiment, the interface between the substrate and the thermally conductive element includes a dielectric-to-dielectric direct bond. In one embodiment, during operation of the thermoelectric unit, heat is dissipated from the substrate through the thermally conductive element to the heat sink.

[0034] In another aspect, the disclosed technology relates to a microelectronic device having a first integrated device die, a substrate disposed on the first integrated device die, at least one thermoelectric unit disposed in or on the substrate, and a second integrated device die disposed on the substrate, the thermoelectric unit configured to transfer heat laterally from at least one of the first and second integrated device die. In one embodiment, the substrate has a thickness in a first direction, and the thermoelectric unit is configured to transfer heat at least along a second direction orthogonal to the first direction. In one embodiment, the thermoelectric unit is electrically connected to a through-substrate via disposed in the first integrated device die such that the thermoelectric unit is controlled by the first integrated device die. In one embodiment, the substrate is directly bonded to the first integrated device die without adhesive. In one embodiment, the second integrated device die is directly bonded to the substrate without adhesive. In one embodiment, a heat sink is attached to at least the substrate. In one embodiment, a thermally conductive element is disposed between the substrate and the heat sink. In one embodiment, the thermoelectric unit is configured to laterally transfer heat from the first and second integrated devices to a thermal path that transfers heat vertically to the heat sink. In one embodiment, a third integrated device die is disposed on the substrate. In one embodiment, the second integrated device die or the third integrated device die is electrically connected to the at least one thermoelectric unit. In one embodiment, the first integrated device die and the second integrated device die are in electrical communication via through-substrate vias. In one embodiment, the at least one thermoelectric unit is disposed within the substrate.

[0035] In another aspect, the disclosed technology relates to a microelectronic device, the microelectronic device comprising a semiconductor device and a substrate disposed on the semiconductor device, the substrate having a thickness in a first direction, the microelectronic device further comprising a plurality of thermoelectric units disposed within the substrate, a first portion of the thermoelectric units configured to transfer heat along the first direction and a second portion of the thermoelectric units configured to transfer heat laterally along a second direction orthogonal to the first direction. In one embodiment, the first portion of the thermoelectric units is disposed on the second portion of the thermoelectric units. In one embodiment, both the first and second portions of the thermoelectric units are disposed on the semiconductor device. In one embodiment, the thermoelectric units are electrically connected to through-substrate vias disposed within the semiconductor device. In one embodiment, the substrate is directly bonded to the semiconductor device without adhesive. In one embodiment, the thermoelectric units are electrically connected to through-substrate vias disposed within the semiconductor device.

[0036] In another aspect, the disclosed technology relates to a microelectronic device comprising a semiconductor device, a substrate disposed on the semiconductor device, a plurality of thermoelectric units disposed within the substrate, and a plurality of temperature sensors configured to detect a local temperature in the semiconductor device. In one embodiment, the plurality of thermoelectric units are configured to transfer heat along a path in a plane perpendicular to a direction along a thickness of the substrate, the path including at least one turn in the plane. In one embodiment, the thermoelectric units are configured to transfer heat away from the local hot spot by thermal transfer. In one embodiment, the substrate has a thickness in a first direction, and the thermoelectric units are configured to transfer heat along a second direction perpendicular to the first direction. In one embodiment, the plurality of temperature sensors are disposed within the semiconductor device or the substrate. In one embodiment, the microelectronic device further comprises a plurality of electrical contact pairs, each electrical contact pair independently controlling a portion of the plurality of thermoelectric units. In one embodiment, the thermoelectric units are actuated by the semiconductor device, the substrate, or an external chip.

[0037] In another aspect, the disclosed technology relates to a microelectronic device having a semiconductor device, a substrate disposed on the semiconductor device, and a plurality of thermoelectric units disposed within the substrate, the substrate configured to allow zoned control for cooling the semiconductor device by independently controlling subgroups of the plurality of thermoelectric units. In one embodiment, the substrate has a thickness in a first direction, and the thermoelectric units are configured to transfer heat along a second direction orthogonal to the first direction. In one embodiment, a plurality of temperature sensors are disposed within the semiconductor device or the substrate, each temperature sensor being associated with an electrical contact for actuating a portion of the thermoelectric unit. In one embodiment, the microelectronic device further includes a plurality of electrical contact pairs, each electrical contact pair independently controlling a portion of the plurality of thermoelectric units. In one embodiment, the thermoelectric units are actuated by the semiconductor device, the substrate, or an external chip.

[0038] Unless the context clearly requires otherwise, throughout the specification and claims, the terms "comprise", "comprising", "include", "including" and the like are to be construed in an inclusive sense, i.e., "including, but not limited to", as opposed to an exclusive or exhaustive sense. As used generally herein, the term "coupled" means two or more elements that are directly connected to each other or that are connected to each other through one or more intermediate elements. Similarly, as used generally herein, the term "coupled" means two or more elements that are directly connected to each other or that are connected to each other through one or more intermediate elements. In addition, the terms "herein," "above," "below," and terms of similar import used in the parent application refer to the application as a whole and not to any particular portion of the application. Furthermore, as used herein, when a first element is described as being located "on" or "over" a second element, the first element may be directly located on or over the second element such that the first element and the second element are in direct contact with each other, or the first element may be indirectly located on or over the second element such that one or more elements are interposed between the first element and the second element. Where the context permits, terms in the above detailed description using the singular or plural may include the plural or singular, respectively. The term "or" in reference to a list of two or more items includes all of the following interpretations of that term: any of the items in the list, all of the items in the list, and any combination of the items in the list.

[0039] Furthermore, conditional terms used in the specification, particularly "can," "could," "might," "may," "eg," "for example," "such as," and the like, unless expressly specified otherwise or understood otherwise within the context in which they are used, are generally intended to imply that certain embodiments include certain features, elements, and / or conditions and that other embodiments do not include certain features, elements, and / or conditions. Thus, such conditional terms are generally not intended to imply that features, elements, and / or conditions are present in any required manner for one or more embodiments.

[0040] Although certain embodiments have been described, these embodiments are provided by way of example only and are not intended to limit the scope of the invention. Indeed, the novel apparatus, methods, and systems described herein may be embodied in a variety of other forms, and furthermore, various omissions, substitutions, and modifications in the form of the methods and systems described herein may be made without departing from the scope of the invention. For example, although blocks are shown in a given arrangement, alternative embodiments may perform substantially the same functions with different components and / or circuit topologies, and some blocks may be deleted, moved, added, divided, combined, and / or modified. Each of these blocks may be embodied in a wide variety of ways. Any suitable combination of elements and acts of the various embodiments described above may be combined to provide further embodiments. The scope of the invention as set forth in the appended claims and equivalents thereto is intended to include such forms or modifications within the scope and spirit of the invention.

Claims

1. 1. A microelectronic device comprising: a substrate having a thickness in a vertical direction; at least one thermoelectric unit disposed within the substrate; an active die disposed vertically adjacent to the substrate and the at least one thermoelectric unit; The microelectronic device, wherein the at least one thermoelectric unit is configured to transfer heat from the active die along a second lateral direction orthogonal to the vertical direction.

2. The microelectronic device of claim 1 , wherein the substrate has a surface configured for direct hybrid bonding.

3. The microelectronic device of claim 1 , wherein the substrate further comprises an opposing surface configured for direct hybrid bonding.

4. 10. The microelectronic device of claim 1, further comprising at least one additional thermoelectric unit disposed within the substrate, the at least one additional thermoelectric unit configured to transfer heat along the second lateral direction.

5. The microelectronic device of claim 4 , further comprising a thermally conductive plate disposed between the at least one thermoelectric unit and the at least one additional thermoelectric unit.

6. The microelectronic device of claim 5 , wherein the thermally conductive plate is electrically insulating.

7. 10. The microelectronic device of claim 1, further comprising at least one additional thermoelectric unit disposed within the substrate, the at least one additional thermoelectric unit configured to transfer heat along a third direction non-parallel to the second lateral direction and the vertical direction.

8. The microelectronic device of claim 1 , further comprising at least one additional thermoelectric unit disposed within the substrate, the at least one additional thermoelectric unit configured to transfer heat along the vertical direction.

9. The microelectronic device of claim 1 , wherein the thickness is less than or equal to 100 microns.

10. The microelectronic device of claim 8 , wherein the at least one additional thermoelectric unit is configured to transfer heat in the vertical direction.

11. 11. The microelectronic device of claim 10, wherein the at least one thermoelectric unit is associated with a pair of electrical contacts configured to pass electrical current within the at least one thermoelectric unit along both the vertical direction and / or the second lateral direction.

12. 11. The microelectronic device of claim 10, wherein the at least one thermoelectric unit is associated with two pairs of electrical contacts, each pair of electrical contacts configured to conduct electrical current within the at least one thermoelectric unit along one of the vertical direction and the second lateral direction.

13. 1. A microelectronic device comprising: a substrate having a thickness in a vertical direction; at least one thermoelectric unit disposed in or on the substrate; an active die disposed vertically adjacent to the substrate and the at least one thermoelectric unit; The at least one thermoelectric unit is configured to transfer heat radially from the active die in a plane perpendicular to the vertical direction.

14. The microelectronic device of claim 13 , wherein the substrate is direct bonded to a semiconductor element.

15. The microelectronic device of claim 13 , wherein the substrate further comprises an opposing surface configured for direct hybrid bonding.

16. The microelectronic device of claim 13 , wherein the thickness is less than or equal to 100 microns.

17. 14. The microelectronic device of claim 13, further comprising at least one additional thermoelectric unit disposed within the substrate, the at least one additional thermoelectric unit configured to transfer heat along the vertical direction, along a second direction orthogonal to the vertical direction, or along a third direction non-parallel to the second direction and the vertical direction.

18. 20. The microelectronic device of claim 17, further comprising a thermally conductive plate disposed between the at least one thermoelectric unit and the at least one additional thermoelectric unit.

19. 1. A microelectronic device comprising: A semiconductor element; a substrate provided on the semiconductor element; a plurality of thermoelectric units provided within the substrate; and a plurality of temperature sensors configured to detect local temperatures within the semiconductor element.

20. 20. The microelectronic device of claim 19, wherein the plurality of thermoelectric units are configured to transfer heat along a path in a plane perpendicular to a direction along a thickness of the substrate, the path including at least one turn in the plane.

21. 20. The microelectronic device of claim 19, wherein the plurality of thermoelectric units are configured to transfer heat away from local hot spots by heat transfer.

22. 20. The microelectronic device of claim 19, wherein the substrate has a thickness in a first direction, and the plurality of thermoelectric units are configured to transfer heat along a second direction orthogonal to the first direction.

23. The microelectronic device of claim 19, further comprising an active die positioned vertically adjacent to the substrate, wherein one thermoelectric unit of the plurality of thermoelectric units is configured to transfer heat from the active die along a second lateral direction perpendicular to the vertical direction.

24. 20. The microelectronic device of claim 19, wherein the plurality of temperature sensors are disposed within the semiconductor element or the substrate.

25. 20. The microelectronic device of claim 19, further comprising a plurality of pairs of electrical contacts, each pair of electrical contacts independently controlling a portion of the plurality of thermoelectric units.

26. The microelectronic device of claim 19 , wherein the plurality of thermoelectric units are powered by the semiconductor element, the substrate, or an external chip.

27. 1. A microelectronic device comprising: A semiconductor element; a substrate provided on the semiconductor element; a plurality of thermoelectric units disposed within the substrate; the substrate is configured to enable zoned control of cooling of the semiconductor device by independently controlling subgroups of the plurality of thermoelectric units; A microelectronic device, wherein a plurality of temperature sensors are disposed within the semiconductor element or the substrate, and each temperature sensor of the plurality of temperature sensors is associated with an electrical contact to activate a portion of the plurality of thermoelectric units.

28. The microelectronic device of claim 27, further comprising an active die positioned vertically adjacent to the substrate, the substrate having a thickness in the vertical direction, and the plurality of thermoelectric units configured to transfer heat from the active die along a second lateral direction perpendicular to the vertical direction.

29. 30. The microelectronic device of claim 27, further comprising a plurality of pairs of electrical contacts, each pair of electrical contacts independently controlling a portion of the plurality of thermoelectric units.

30. 30. The microelectronic device of claim 27, wherein the plurality of thermoelectric units are powered by the semiconductor element, the substrate, or an external chip.

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