Semiconductor substrate assembly and manufacturing method therefor

Abstract

According to one embodiment of the present disclosure, a substrate has a bonding surface that comprises: a plurality of first signal transmission pads arranged in an array configuration; a plurality of first dummy pads arranged in a similar array configuration in an area on the bonding surface other than that of the first signal transmission pads; and an insulation surface. In the substrate, a plurality of metal pads including the signal transmission pads and the first dummy pads are arranged substantially uniformly in an array configuration across substantially the entirety of the bonding surface, and each of the plurality of the first metal pads is enclosed by the insulation surface, and the dummy pads are connected to a power source or ground. The present invention further provides a bonding method for a pair of such substrates and a bonding structure of said substrates.

Description

Semiconductor substrate assembly and manufacturing method thereof

[0001] The present disclosure relates to a semiconductor substrate assembly and a method for manufacturing the same.

[0002] In recent years, with the development of cloud computing, information processing involving big data has increased. In particular, artificial intelligence (AI) processing requires frequent and high-speed access to big data. In hardware, structures such as chiplets and 3D packaging modules have evolved. Semiconductor electronic circuits have multilayer stacked structures, in which two or more layers are stacked. Electrical connections are formed between wafers, between wafers and chips, and between chips and interposers. Alternatively, semiconductor electronic circuits have three-dimensional structures, in which wafers or chips are stacked. This allows, for example, memory modules to be formed, increasing the access bandwidth of semiconductor memories. Wafer-to-wafer bonding is also used in power semiconductors.

[0003] However, the manufacturing process for these laminated and three-dimensional structures, including the connection between multiple layers, is complicated. Currently, their reliability is a serious issue. Furthermore, despite the high demand for high-speed signals, no structure has been proposed that satisfies both the required bonding strength and high-speed signal transmission characteristics.

[0004] In some embodiments of the present disclosure, a bonding structure or bonded assembly is provided, comprising: a first substrate having a first bonding surface with a first signal carrying metal region and a first ground metal region insulated from the first signal carrying metal region; and a second substrate bonded to the first substrate, having a second bonding surface with a second signal carrying metal region and a second ground metal region insulated from the second signal carrying metal region. Also provided is a method for bonding the first and second substrates. In some embodiments, the first signal carrying metal region and the second signal carrying metal region are bonded together. In some embodiments, the first ground metal region and the second ground metal region are bonded together. In some embodiments, the ground metal region is disposed to surround the signal carrying metal region.

[0005] In some embodiments of the present disclosure, there is provided a bonding structure comprising: i) a first substrate having a first bonding surface, the first bonding surface comprising: a plurality of first signal transmission pads arranged in an array; a plurality of first dummy pads arranged in a similar array on a portion of the first bonding surface other than the portion where the plurality of first signal pads are arranged; and a first insulating surface; wherein a plurality of first metal pads including the plurality of first signal transmission pads and the plurality of first dummy pads are arranged in an approximately uniform array over substantially the entire first bonding surface, each of the plurality of first metal pads being surrounded by a first insulating surface, and the plurality of first dummy pads being connected to a power supply or a ground; and ii) a second substrate bonded to the first substrate, the second bonding surface comprising: a plurality of second signal transmission pads arranged in an array; a plurality of second dummy pads arranged in a similar array on a portion of the second bonding surface other than the portion where the plurality of second signal pads are arranged; and a second insulating surface; a second substrate, wherein a plurality of second metal pads including the plurality of second signal transmission pads and the plurality of second dummy pads are uniformly arranged in an array over substantially the entire second bonding surface, each of the plurality of second metal pads being surrounded by a second insulating surface, and the plurality of second dummy pads being connected to a power supply or a ground, wherein each of the plurality of first signal transmission metal pads is bonded to each of the plurality of second signal transmission metal pads, and each of the plurality of first dummy pads is bonded to each of the plurality of second dummy pads. Also provided is a method for bonding the first substrate and the second substrate.

[0006] In some embodiments, the first dummy pads are arranged to surround the first signal transmission pads, and / or the second dummy pads are arranged to surround the second signal transmission pads.

[0007] In some embodiments, one or at least one of the plurality of first dummy pads and the plurality of second dummy pads is connected to a power supply or a ground.

[0008] In some embodiments, the first metal pads and the second metal pads have rounded shapes. In some embodiments, the first metal pads include a first wiring metal region and / or the second metal pads include a second wiring metal region. In some embodiments, the first signal transmitting pads include a first differential signal plus metal region and a first differential signal minus metal region and / or the second signal transmitting pads include a second differential signal plus metal region and a second differential signal minus metal region. In some embodiments, the first insulating surface and the second insulating surface are bonded.

[0009] In some embodiments, at least some of the first metal pads and the second metal pads have metal regions configured to suppress transmission of electromagnetic noise in a direction perpendicular to the first and second bonding surfaces.

[0010] In some embodiments, a bonding structure is provided, comprising: a first substrate having a first bonding surface including a pair of a first differential signal plus metal region and a first differential signal minus metal region; and a first plane metal region formed to surround the pair of the first differential signal plus metal region and the first differential signal minus metal region; and a second substrate having a second bonding surface including a pair of a second differential signal plus metal region and a second differential signal minus metal region; and a second plane metal region formed to surround the pair of the second differential signal plus metal region and the second differential signal minus metal region, wherein the first differential signal plus metal region and the second differential signal plus metal region are bonded, the first differential signal minus metal region and the second differential signal minus metal region are bonded, and the first plane metal region and the second plane metal region are bonded.

[0011] According to the technology of the present disclosure, for example, it is possible to realize a mechanically strong or highly reliable joint. Alternatively, for example, it is possible to maintain good high-speed signal transmission characteristics within an electronic circuit. Furthermore, it is possible to construct an electronic circuit, module, or system having such a three-dimensional structure.

[0012]

[0013] Further aspects and advantages of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, wherein only illustrative embodiments of the present disclosure are shown and described. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

[0013] 1A is a cross-sectional view schematically illustrating the structure of a pair of substrates to be bonded according to one embodiment; 1B is a cross-sectional view schematically illustrating the structure of a substrate assembly produced by bonding the pair of substrates. 2A is a cross-sectional view schematically illustrating the structure of a pair of substrates to be bonded according to one embodiment; 2B is a cross-sectional view schematically illustrating the structure of a substrate assembly produced by bonding the pair of substrates. 2A is a cross-sectional view schematically illustrating the structure of a substrate assembly including three substrates according to one embodiment. 2B is a cross-sectional view schematically illustrating the structure of a substrate assembly including three substrates according to one embodiment. 2C is a perspective view schematically illustrating the structure of substrates used in a substrate assembly according to one embodiment. 2D is a top view schematically illustrating the configuration of bonding surfaces of substrates according to one embodiment. 2E is a top view schematically illustrating the configuration of bonding surfaces of substrates according to one embodiment. 2F is a top view schematically illustrating the configuration of bonding surfaces of substrates according to one embodiment. 2G is a top view schematically illustrating the configuration of bonding surfaces of substrates according to one embodiment. 2H is a top view schematically illustrating the configuration of bonding surfaces of substrates according to one embodiment. 2H is a top view schematically illustrating the configuration of bonding surfaces of substrates according to one embodiment. FIG. 1 is a perspective view illustrating the structure of a substrate assembly used in a simulation according to an embodiment; FIG. 2 is a graph illustrating transmission characteristics and reflection characteristics by simulation; FIG. 3 is a top view and a perspective view illustrating the structure of a substrate assembly used in a simulation according to an embodiment; FIG. 4 is a top view and a perspective view illustrating the structure of a substrate assembly used in a simulation according to an embodiment; FIG. 5 is a top view and a perspective view illustrating the structure of a substrate assembly used in a simulation according to an embodiment; FIG. 6 is a top view and a perspective view illustrating the structure of a substrate assembly used in a simulation according to an embodiment; FIG. 7 is a graph illustrating noise transmission characteristics of each example by simulation; FIG. 8 is a top view and a perspective view illustrating the structure of a substrate assembly used in a simulation according to some embodiments;FIG. 1 is a graph showing the noise transmission characteristics of each example by simulation; FIG. 2 is a top view showing the structure of a substrate assembly used in simulations according to several examples; FIG. 3 is a graph showing the noise transmission characteristics of each example by simulation; FIG. 4 is a cross-sectional view schematically showing the structure of a substrate according to the prior art; FIG. 5 is a cross-sectional view schematically showing the structure of a substrate according to an embodiment; FIG. 6 is a top view schematically showing the structure of a wafer substrate according to an embodiment, for explaining propagation of a bonding wave; FIG. 7 is a schematic cross-sectional view of a substrate for explaining a method of bonding a pair of substrates according to an embodiment.

[0014] 1. Structure of the Substrate and Bonded Body As used herein, the term "substrate" generally refers to a flat plate of semiconductor or insulator material. However, this term should not be interpreted limitingly. The term "substrate" should be broadly interpreted to refer to a structure on which one or more materials or one or more layers of materials can be deposited. The substrate may include one or more layers of material deposited thereon. For example, but not limited to, the substrate may include a wafer or chip including one or more layers of material. A dielectric layer, a metal layer, etc. is deposited thereon. The substrate may have a flat plate shape having a substantially constant thickness in two-dimensional plane directions. However, the shape of the substrate is not limited to a flat plate. The substrate may also have a three-dimensional shape.

[0015] The substrate may be a chip, a wafer, an element, a module, etc. The substrate may be a printed circuit board (PCB), an interposer, an interposer substrate, etc. The substrate may be a single-sided, double-sided, or multi-layer PCB or interposer. The bonded substrates may be of the same type or may be substrates belonging to different types or categories. For example, chip to chip, wafer to wafer, or chip to wafer may be bonded. For example, three or more substrates may be bonded. For example, one or more interposer substrates may be bonded to multiple semiconductor chips so that they are sandwiched between them.

[0016] In some embodiments, the substrate has a bonding surface. A bonding surface may be defined as a surface or surface area that is bonded to another substrate. In some embodiments, the bonding surface may have a metallic region that is substantially made of a conductive material. In some embodiments, the bonding surface may have a non-metallic region that is substantially made of a non-conductive material. The bonding surface may have a metallic region and a non-metallic region.

[0017] As used herein, the term "metal region" generally refers to a surface region formed on a surface or joining surface of a substrate and consisting essentially of a conductive material. In some embodiments, the metal region may be defined with respect to a dimension perpendicular to the surface of the substrate.

[0018] In some embodiments, the surface (top surface) of the metal region may be flat. The flat surface of the metal region may be substantially parallel to the bonding surface. In some embodiments, the surface of the metal region may be curved or uneven. The top surface of the metal region may be configured to be bonded to another substrate. In some aspects, the top surface of the metal region may be configured to protrude above the top surface of a non-metal region provided on the same bonding surface. In some aspects, the top surface of the metal region may be substantially flush with the top surface of a non-metal region provided on the same bonding surface.

[0019] The metal region may be connected to a through electrode (sometimes referred to as a TSV (through-silicon via) in this specification) that partially or completely penetrates the inside of the substrate. The metal region may be connected to an extraction electrode that is arranged along the surface of the substrate or that passes through the inside and leads to the edge.

[0020] The term "metal" as used herein generally refers to a conductive material unless otherwise specified. A "metal" may consist essentially of or include a metallic material, a non-metallic material, or a mixture thereof. A conductive material may be, for example, but not limited to, a material that is used or can be used as a semiconductor wiring material. A metallic material (hereinafter sometimes referred to as "metal") may be selected from the group consisting of aluminum (Al), copper (Cu), cobalt (Co), ruthenium (Ru), silver (Ag), and gold (Au), or a subset thereof. A metallic material may also be other metals. A metallic material may also be a mixture or alloy of any two or more of these. A conductive material may also be a non-metallic conductive material. A conductive material may consist of or include, for example, but not limited to, carbon (C). Carbon materials include, for example, but not limited to, multi-layer graphene (MLG), carbon nanotubes (CNT), etc.

[0021] In some embodiments, the substrate may have signal carrying metal regions and ground metal regions on its mating surface.

[0022] As used herein, the term "signal-transmitting metal region" refers to a metal region in a bonded structure that is used for transmitting signals. Multiple signal-transmitting metal regions may be disposed on the bonded surface. In the bonded structure, signals are transmitted through the signal-transmitting metal regions. In some embodiments, the bonded structure may have a high-speed signal transmission structure in the GHz and THz bands and a capability to support 10 W to 1000 W. The bonded structure may also be a connection structure used in information processing devices.

[0023] The signal carrying metal region may comprise at least one signal carrying metal region for carrying analog signals. The signal carrying metal region may comprise at least one signal carrying metal region for carrying digital signals. The signal carrying metal region may comprise at least one analog signal carrying metal region and at least one digital signal carrying metal region on the same interface.

[0024] As used herein, the term "ground metal region" refers to a metal region in a joint that is connected to, for example, ground and a power supply and is not intended for signal transmission. In some embodiments, a "ground metal region" may be defined as a metal region other than a signal transmission metal region. Multiple ground metal regions may be disposed on a joint surface. A ground metal region may be connected to the ground of the joint. A "ground metal region" may include a narrowly defined ground metal region connected to ground. In some embodiments, a "ground metal region" may include a power supply metal region connected to a power supply. The power supply provides power to electronic elements within the joint or to which the joint is connected. In some embodiments, a ground metal region may be connected to or configured to be connected to either ground or a power supply in the joint. In some embodiments, a ground metal region may be electrically connected or configured to be connected to a power supply. The power supply may be used to drive electronic elements that output or receive signals transmitted through the joint structure. The power supply may be electrically connected to the electronic elements. A ground metal region may be connected to either polarity of the power supply. The power supply may include multiple power supplies. Multiple power sources may be connected or configured to be connected to multiple ground metal regions.

[0025] In some embodiments, the ground metal region may have a thermal conduction function. Such a ground metal region may be referred to as a heat sink metal region. The heat sink metal region may be connected to thermal vias that penetrate the substrate. This may, for example, conduct heat generated within a device or substrate structure to the outside or cool it. Thermal vias may be connected to each other across multiple layers or substrates, or to heat sink metal regions of multiple layers or substrates. The heat sink metal region may be connected to a heat sink, such as vias. The heat sink may be located on, for example, the final layer (top or bottom layer) of a substrate structure. In some embodiments, the heat sink metal region may be connected to or located within a stack structure within a power device. A power device may include a heat sink metal region.

[0026] The ratio (a / A) of the total area (a) of the signal carrying metal regions and ground metal regions to the area (A) of the mating surface on which they are located may be equal to or greater than any of the following values: 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95%. In some embodiments, this ratio (a / A) may be 25% or greater. In some embodiments, this ratio (a / A) may be 30% or greater. In some embodiments, this ratio (a / A) may be 50% or greater. In some embodiments, this ratio (a / A) may be 60% or greater. This ratio may vary from substrate to substrate or from substrate surface to substrate surface within a single mating assembly.

[0027] In some embodiments, on the same interface, the area of ​​the ground metal region may be larger than the area of ​​the first or second signal carrying metal region.

[0028] By bonding a ground metal region having a relatively large area, the bonding strength of the two bonded substrates can be increased sufficiently, for example, to provide sufficient strength against thermal stress or the application of external force (such as an impact from a drop).

[0029] The ground metal region and the signal carrying metal region may be insulated from each other. The ground metal region and the signal carrying metal region may be insulated within the joining surface. The ground metal region and the signal carrying metal region may be insulated from each other at all times throughout the entire joint. The ground metal region and the signal carrying metal region may be insulated by an insulating material disposed between them. The insulating material may form an insulating surface at the joining surface. The insulating surface may be configured to contact or be joined to another substrate. The ground metal region and the signal carrying metal region may be arranged to be non-contacting or non-contacting with each other within the joining surface. The ground metal region and the signal carrying metal region may be insulated from each other by a gas or a substantial vacuum.

[0030] In some aspects, the ground metal region and the signal carrying metal region may be spaced apart from one another within or along the joining plane by a distance equal to or greater than any of 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, or 1 μm.

[0031] The ground metal regions may be disposed within the respective joint planes and surround the signal carrying metal regions.

[0032] In some embodiments, the ground metal region may have metal material formed or disposed in a substantially gapless or planar manner across its entire area, or in other words, the metal area of ​​the ground metal region may be formed substantially solidly across its entire area.

[0033] In some embodiments, the metal material of the ground metal region may be formed in a portion of the region. In some aspects, the ground metal region may have non-metallic material-occupied portions (also referred to as voids or non-metallic material portions) where no metal material is disposed. The metal material or non-metallic material-occupied portions may be periodically disposed or formed throughout or in part of the ground metal region. For example, the metal material or non-metallic material-occupied portions may be disposed or formed in a mesh pattern throughout or in part of the ground metal region.

[0034] The area ratio of the unoccupied metal material within the ground metal region may be equal to or greater than any of the following values: 5%, 10%, 20%, 30%, 40%, 50%, 60%.

[0035] The area ratio of the unoccupied metal material within the ground metal region may be equal to or less than any of the following values: 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, or even less.

[0036] The substrate assembly or junction structure of the present disclosure may be connected to, configured to be connected to, or contain various electronic circuits, etc. The electronic circuit may be an optoelectronic circuit (in this specification, an "optoelectronic circuit" or the like may also be simply referred to as an "electronic circuit" or the like). The electronic circuit includes, for example, but is not limited to, an electronic element, an electronic circuit module, an electronic product, an electronic system, etc. The electronic element includes, for example, but is not limited to, a transistor (MOS, CMOS, FET, CMOS, etc.), an operational amplifier, a diode, a resistor, an inductor, a capacitor, a photocoupler, a transformer, a relay, etc. The electronic circuit may include one or both of a digital circuit and an analog circuit.

[0037] The electronic circuit may be a digital circuit or element, or may be a logic circuit. The electronic circuit may be a logic circuit or an integrated circuit (IC) (e.g., SSI, MSI, LSI, VLSI, ULSI, WSI, SoC, CCD or CMOS image sensor, etc.). The electronic circuit may be a central processing unit (CPU), a graphics processing unit (GPU), etc. Examples of electronic circuits include, but are not limited to, gate circuits such as AND gates, OR gates, NOT gates, NAND gates, NOR gates, and ExOR gates; logic function blocks such as flip-flops, counters, registers, shift registers, latches, encoders / decoders, multiplexers / demultiplexers, adders, and comparators; circuits with amplification functions such as buffers and inverters; switches, multiplexers, oscillators, and phase-locked loops (PLLs), etc.

[0038] The electronic circuit may be an analog circuit or element, and includes, but is not limited to, an amplifier circuit, an oscillator circuit, a filter circuit, an arithmetic circuit, an impedance matching circuit, a modulation circuit, a power supply circuit, a high frequency circuit, and the like.

[0039] First Embodiment One embodiment will be described with reference to Fig. 1. Fig. 1A shows a schematic diagram of two substrates 110 and 120 to be bonded together.

[0040] The substrate 110 includes a ground metal region 111 and a signal transmission metal region 113 formed on the bonding surface of a substrate body formed of a semiconductor or an insulator. The substrate 110 further includes a through electrode 112 connected to the ground metal region 111 and a through electrode 114 connected to the signal transmission metal region 113, which are formed to penetrate the substrate 110. The ground metal region 111 and the signal transmission metal region 113 are formed to protrude from a surface (insulating surface) 115 on the bonding surface of the substrate body 110. In FIG. 1A , the ground metal region 111 and the signal transmission metal region 113 are formed so that their surfaces are approximately flush with the insulating surface 115 or the substrate body 110.

[0041] The substrate 120 has a similar configuration to the substrate 110. The substrate 120 includes a ground metal region 121 and a signal transmission metal region 123 formed on the bonding surface of a substrate body formed of a semiconductor or an insulator. The substrate 120 further includes a through electrode 122 connected to the ground metal region 121 and a through electrode 124 connected to the signal transmission metal region 123, which are formed to penetrate the substrate 120. The ground metal region 121 and the signal transmission metal region 123 are formed to protrude from a surface (insulating surface) 125 on the bonding surface of the substrate body 120. In FIG. 1A , the ground metal region 121 and the signal transmission metal region 123 are formed so that their surfaces are approximately flush with the insulating surface 125 or the substrate body 120.

[0042] As shown in FIG. 1B , the ground metal region 111 of the substrate 110 is bonded to the ground metal region 121 of the substrate 120, and the signal transmission metal region 113 of the substrate 110 is bonded to the signal transmission metal region 123 of the substrate 120. This bonding forms a bonding interface 150 between the metal regions. This electrically connects the ground metal region 111 and the through electrode 112 of the substrate 110 to the ground metal region 121 and the through electrode 122 of the substrate 120. This also bonds the substrates 110 and 120, producing the substrate assembly 100. Here, the insulating surface 115 of the substrate 110 and the insulating surface 125 of the substrate 120 are not in contact with or bonded to each other. The insulating surface 115 of the substrate 110 and the insulating surface 125 of the substrate 120 may not be in contact with or bonded to each other, partially or entirely.

[0043] Not only in this embodiment, but also in any other case, by joining the ground metal regions, a high-strength joining interface can be formed.

[0044] In some embodiments, the insulating surfaces of the substrates may be configured to contact or be bonded together before, during, or after the bonding process. One embodiment is described with reference to Figure 2. Figure 2A shows a schematic of two substrates 210, 220 to be bonded.

[0045] The substrate 210 includes a ground metal region 211 and a signal transmission metal region 213 formed on the bonding surface of a substrate body formed of a semiconductor or an insulator. The substrate 210 of FIG. 2 further includes a through electrode 212 connected to the ground metal region 211 and a through electrode 214 connected to the signal transmission metal region 213, which are formed to penetrate the substrate 210. The ground metal region 211 and the signal transmission metal region 213 are formed to be substantially flush with a surface (insulating surface) 215 on the bonding surface of the substrate body 210. In other words, the surfaces of the ground metal region 211, the signal transmission metal region 213, and the insulating surface 215 have substantially the same height in the substrate 210. The substrate 220 also has a similar configuration to the substrate 210.

[0046] As shown in FIG. 2B , the ground metal region 211 of the substrate 210 is bonded to the ground metal region 221 of the substrate 220, the signal transmission metal region 213 of the substrate 210 is bonded to the signal transmission metal region 223 of the substrate 220, and the insulating surface 215 of the substrate 210 is bonded to the insulating surface 225 of the substrate 220. This bonding forms a bonding interface 250 between the metal regions. This electrically connects the ground metal region 211 and the through electrode 212 of the substrate 210 to the ground metal region 221 and the through electrode 222 of the substrate 220. This also electrically connects the substrates 210 and 220 to each other, producing the substrate assembly 200. Here, the insulating surface 215 of the substrate 210 and the insulating surface 225 of the substrate 220 are in contact with or bonded to each other. The insulating surface 215 of the substrate 210 and the insulating surface 225 of the substrate 220 are in partial or total contact with or bonded to each other.

[0047] Not only in this embodiment, but also in any other case, by bonding insulating surfaces, a bonding interface with higher strength can be formed.

[0048] In some embodiments, bonding of the insulating surfaces can occur even when the metal regions protrude relative to the insulating surface, as in Figure 1. For example, the metal regions may first contact the other substrate, and then, or simultaneously, the insulating surface may contact the other substrate due to elastic or plastic deformation of the substrate. This phenomenon is more likely to occur when the insulating surface has a high bonding strength (e.g., is activated).

[0049] In some embodiments, the metal region may be recessed relative to the insulating surface (not shown). In other words, the metal region may be lowered relative to the insulating surface. In this case, the insulating surface contacts the other substrate. However, later, due to expansion caused by heating, the metal region may contact the other substrate. Alternatively, atoms of the metal region may diffuse due to heating and reach the other substrate.

[0050] <Embodiment 3: Multilayer Structure 1> In some embodiments, three or more substrates may be bonded together. One embodiment will be described with reference to FIG. 3. The substrate assembly 300 shown in FIG. 3 includes an upper substrate 310, a lower substrate 330, and an intermediate substrate 320 sandwiched between them. Here, as shown in embodiment 1, each substrate has a metal region protruding from the insulating surface at each bonding surface. The intermediate substrate 320 may be, for example, but not limited to, an interposer substrate.

[0051] A ground metal region 321a and a signal transmission metal region 323a are arranged on the upper surface of the intermediate substrate 320, and are bonded to the ground substrate region 311 and the signal transmission metal region 313 of the upper substrate 310, respectively. A ground metal region 321b and a signal transmission metal region 323b are arranged on the lower surface of the intermediate substrate 320, and are bonded to the ground substrate region 331 and the signal transmission metal region 333 of the lower substrate 330, respectively. This bonding forms bonding interfaces 350a and 350b between the metal regions. This electrically connects the ground metal region 311 and the through electrode 312 of the upper substrate 310, the ground metal region 321a, the through electrode 322 and the ground metal region 321b of the intermediate substrate 320, and the ground metal region 331 and the through electrode 332 of the lower substrate 330. Furthermore, the signal transmission metal region 313 and the through electrode 314 of the upper substrate 310, the signal transmission metal region 323a, the through electrode 324 and the signal transmission metal region 323b of the intermediate substrate 320, and the signal transmission metal region 333 and the through electrode 334 of the lower substrate 330 are electrically connected. The upper substrate 310, the intermediate substrate 320 and the lower substrate 330 are joined together to form the substrate assembly 300.

[0052] <Embodiment 4: Multilayer Structure 2> One embodiment will be described with reference to Figure 4. The substrate assembly 400 shown in Figure 4 includes an upper substrate 410, a lower substrate 430, and an intermediate substrate 420 sandwiched between them. Here, as shown in embodiment 2, the metal regions of each substrate are formed substantially flush with the insulating surface at each bonding surface. As in embodiment 3, the intermediate substrate 420 may be, for example, but not limited to, an interposer substrate.

[0053] A ground metal region 421a, a signal transmission metal region 423a, and an insulating surface 425a are arranged on the upper surface of the intermediate substrate 420, and are bonded to the ground substrate region 411, the signal transmission metal region 413, and the insulating surface 415 of the upper substrate 410, respectively. A ground metal region 421b, a signal transmission metal region 423b, and an insulating surface 425b are arranged on the lower surface of the intermediate substrate 420, and are bonded to the ground substrate region 431, the signal transmission metal region 433, and the insulating surface 435 of the lower substrate 430, respectively. This bonding forms bonding interfaces 450a, 450b between the metal regions. This electrically connects the ground metal region 411 and the through electrode 412 of the upper substrate 410, the ground metal region 421a, the through electrode 422, and the ground metal region 421b of the intermediate substrate 420, and the ground metal region 431 and the through electrode 432 of the lower substrate 430. Furthermore, the signal transmission metal region 413 and the through electrode 414 of the upper substrate 410, the signal transmission metal region 423a, the through electrode 424 and the signal transmission metal region 423b of the intermediate substrate 420, and the signal transmission metal region 433 and the through electrode 434 of the lower substrate 430 are electrically connected. Furthermore, the insulating surfaces are bonded to other insulating surfaces. The upper substrate 410, the intermediate substrate 420, and the lower substrate 430 are bonded to form the substrate assembly 400.

[0054] Example 1: Substrate Structure Figure 5 shows, as a non-limiting example, the structure of a substrate 510 that can be used as an interposer. Figure 5 is a perspective view of the substrate 510, and the central insulating or semiconductor portion has been omitted to show the internal structure.

[0055] The substrate 510 shown in FIG. 5 includes a ground metal region 511a, a signal transmission metal region 513a, and a power supply metal region 515a on its top surface, and is configured to be bonded to corresponding regions of the substrate to be bonded from the top surface. Furthermore, a power supply plane 515a-2 is disposed on the second layer from the top and connected to the power supply metal region 515a on the top surface. Wiring 513a-2 connecting multiple signal transmission metal regions 513a is disposed on the second layer from the top. They are insulated from each other by organic insulator 517a. The ground metal region 511a is connected to a corresponding through electrode 512. The signal transmission metal region 513a is connected to a corresponding through electrode 514. The power supply metal region 515a is connected to the power supply plane 515a-2 and a corresponding through electrode 516.

[0056] The substrate 510 shown in FIG. 5 further includes a ground metal region 511b, a signal transmission metal region 513b (not shown), and a power metal region 515b on its underside, which are configured to be bonded to corresponding regions of the substrate to be bonded from the underside. A power plane 515b-2 is disposed on the second layer from the bottom and is connected to the power metal region 515b on the underside. They are insulated from each other by an organic insulator 517b. The ground metal region 511b is connected to a corresponding through electrode 512. The signal transmission metal region 513b (not shown) is connected to a corresponding through electrode 514. The power metal region 515b is connected to a corresponding through electrode 516.

[0057] The interface may include a digital signal transmission area and an analog signal transmission area, or may include only one of them.

[0058] 6 shows, as an example, the configuration of a bonding surface 600 including an analog signal transmission region 610 and a digital signal transmission region 650. The configuration shown in FIG. 6 may be used, for example but not limited to, for either an interposer or a PCB.

[0059] As shown in FIG. 6, the interface 600 includes an analog signal transmission area 610 and a digital signal transmission area 650 .

[0060] The analog signal transmission region 610 includes an analog ground metal region 611 and an analog signal transmission metal region 613. A plurality of analog signal transmission metal regions (or pads) 613 are arranged. The analog ground metal region 611 is spaced apart from the analog signal transmission metal regions 613 and is arranged to surround them. The analog ground metal region 611 is connected to ground (not shown). The analog signal transmission region 613 may be connected to, or configured to be connected to, analog elements. The analog signal transmission area 613 may correspond to various pins, including, for example but not limited to: gate voltage (LNA_VDD), ground (LNA_GND), IN (LNA_IN), and NIN (LNA_NIN) of the low noise amplifier (LNA); gate voltage (RI_VDD) and ground (RI_GND) of the ring indicator (RI); gate voltage (TX_VDD), ground (TX_GND), and output differential pair OUT (TX_OUT) and NOUT (TX_NOUT) of the transmission circuit (TX); Vdd (SW_VDD), ground (SW_GND), and control differential pair (SW_CTL, NSW_CTL) of the switch (SW); test refresh (RF) signal (RF_TST); test ground (TEST_GND); clock signal (TCLK_IN); etc. The types of analog signal transmission area 613 shown in FIG. 6 and above are shown as examples, and these groups should not be construed as limiting.

[0061] The digital signal transmission region 650 includes a digital ground metal region 651 and a digital signal transmission metal region 653. A plurality of digital signal transmission metal regions (or pads) 653 are arranged. The digital ground metal region 651 is spaced apart from the digital signal transmission metal regions 653 and is arranged to surround them. The digital ground metal region 651 is connected to ground (not shown). The digital signal transmission metal region 653 may be connected to, or configured to be connected to, digital elements. The digital signal transmission region 613 may correspond to various pins. They are divided into the following categories according to the type of signal they transmit: However, they include, for example, but not limited to, the following: Digital device (D) signal transmission area 661: digital device gate voltage (D_VDD) and ground (D_GND); Control signal transmission area 663: (REQ (Request to Send), AQ (Acquire to Send), ENABLE (Enable for signal)); High-speed bus signal transmission area 665: (Q / NQ (Output Signal / Negative output signal), D / ND (Input Signal / Negative input signal)); Signal transmission area 667 to an adjacent ball grid array; A clock signal transmission area 669 (data clock (DCLK), timing circuit (TADJ), TX_VALID (Transmit Signal Valid), DPH (Data Phase timing), etc.); a serial communication signal transmission area 671 (TXD / NTXD); etc. However, the groupings and types of the digital signal transmission area 652 shown in FIG. 6 are shown as examples, and these groups should not be interpreted as being limiting.

[0062] 7 illustrates a second interface configuration 700 according to one embodiment, including a signal transmission metal region 710 and a ground transmission metal region 720. The interface configuration 700 may be used, for example, but not limited to, on either an interposer or a PCB, such as on one side of a single-ended pad.

[0063] 7 is defined in a central portion 711 of the bonding surface 700. The signal transmission metal region 710 is not formed as a single, continuous, or solid region, but is formed as an individual pin 710. The signal transmission metal region, pin 710, is connected or configured to be connected to the gate voltage (VDD) or ground (GND) of the device.

[0064] 7 is defined around and surrounds the signal transmission metal region 710. The ground metal region 720 is not formed as a single, continuous, or solid region, but is formed in a pin shape. The pin 720, which is a ground metal region, includes a power metal region 721 and a ground metal region 723. These are connected or configured to be connected to a power supply or ground, respectively.

[0065] Example 5: Bonding Surface Configuration 4 FIG. 8 shows a bonding surface 800 according to one example. The bonding surface 800 includes multiple chip regions 810. Each chip region 810 includes a ground metal region 811 and a transmission metal region 813. A wafer including the bonding surface 800 is cut by dicing along boundary lines 830 defined in a grid pattern on the bonding surface 800 at the boundaries of the chip regions. The boundary lines 830, shown by dashed lines in FIG. 8 , are geometrically defined on the wafer and do not necessarily have to be physically provided on the surface of the wafer. The bonding surface 800 shown in FIG. 8 includes a cutting metal region 820 including the boundary lines 830. Therefore, the wafer is cut within this cutting metal region 820 and divided into multiple chip regions 810. The cutting metal region 820 may be connected to ground or configured to be connected to ground, or it may not be connected to ground.

[0066] Example 6: Bonding Surface Configuration 5 FIG. 9 shows a bonding surface 900 according to one example. The bonding surface 900 includes multiple chip regions 910. Each chip region 910 includes a transmission metal region 913. A wafer including the bonding surface 900 is cut by dicing along boundaries 930 defined in a grid pattern on the bonding surface 900 at the boundaries of the chip regions. The bonding surface 900 shown in FIG. 9 includes a peripheral metal region 920 formed along the boundaries 930 and a non-metal region 940 formed through the center of the bonding metal region 930 and including the boundaries 930. The boundaries 930 are defined within or along the non-metal region 940. Alternatively, the boundaries 930 are defined along the non-metal region 940. Therefore, the wafer is cut along the non-metal region 940 of the peripheral metal region 920 to divide it into multiple chip regions 910. In FIG. 9, the peripheral metal region 920 is connected to ground and functions as a ground metal region.

[0067] 8 and 9, the cut metal region 820 and the peripheral metal region 920 may be connected to ground or configured to be connected to ground, or may not be connected to ground. When a wafer having such bonding surfaces 800, 900 is bonded to a substrate such as another wafer, the cut metal region 820 and the peripheral metal region 920 also contribute to the bond. This can improve, for example, but not limited to, the bond strength and / or the signal transmission characteristics.

[0068] The features of the embodiments shown in Figures 6 to 9, in whole or in part, are not limited to the illustrated embodiments, and may be used in combination with each other or incorporated into other embodiments, unless inconsistent.

[0069] 2. Bonding Method First, a bonding method according to one embodiment will be described. At least a pair of substrates is provided. In some embodiments, both substrates of the pair include a ground metal region (or a power metal region) and a signal transmission metal region. Next, the corresponding metal region is brought into contact with a corresponding region of the other substrate. An electrical connection is formed between the predetermined metal regions.

[0070] In other embodiments, one substrate may not necessarily have metal areas corresponding to all of the metal areas of the other substrate. For example, at least one substrate may have ground (or power) metal areas and signal transmission metal areas, while the other substrate may have at least one of them. One substrate may not necessarily have metal areas corresponding to all of the metal areas of the other substrate. The two substrates are joined together to allow for the necessary signal transmission between the two connected substrates.

[0071] The surface of the metal region may be activated before contacting the substrate, or the bonding surface may be subjected to a surface activation treatment. This can improve, for example, the bonding strength. Alternatively, sufficient strength can be obtained at a low temperature. Furthermore, even if heating is performed after contact, the thermal energy can be suppressed.

[0072] <Room temperature bonding method using surface activation>

[0073] The surface activation process may involve irradiating energy or energetic particles onto the surface of a metal area, a metal material (which is usually covered with an oxide in air), a non-metal area, an insulating material, or the like.

[0074] The energetic particles may be generated by accelerating ions or neutral atoms of the gas particles or atoms used, or a mixture thereof, using a particle beam source such as an ion beam source or a fast atom beam (FAB) source. The irradiation of energetic particles may also be performed using a plasma source.

[0075] In some embodiments, a particle beam source can be used to provide the particles with a predetermined kinetic energy, for example, a particle beam source with a background pressure of 1×10 －５The particle beam source operates in a vacuum of 100 Pa (Pascal) or less. By operating a vacuum pump to create a relatively high vacuum, materials removed from the surface of the metal region are efficiently evacuated to the atmosphere. This makes it possible to suppress the adhesion of undesired materials to the exposed new surface. Furthermore, the particle beam source can apply a relatively high acceleration voltage, thereby imparting high kinetic energy to the particles. Therefore, it is believed that the surface layer can be efficiently removed and the new surface can be activated.

[0076] A fast atom beam source (FAB) can be used as the neutral atom beam source. A fast atom beam source (FAB) typically generates a gas plasma, applies an electric field to the plasma, and neutralizes cations of ionized particles by passing them through an electron cloud. In this case, for example, when argon (Ar) is used as the rare gas, the power supplied to the fast atom beam source (FAB) may be set to 1.5 kV (kilovolts) and 15 mA (milliamperes), or may be set to a value between 0.1 and 500 W (watts). For example, by operating the fast atom beam source (FAB) at 100 W to 200 W (watts) and irradiating the fast atom beam of argon (Ar) for about two minutes, the oxides, contaminants, etc. (surface layer) on the surfaces to be bonded can be removed, exposing a new surface.

[0077] As the ion beam source, a cold cathode type ion source can be used.

[0078] The energetic particles may be or include a noble gas, such as argon or another noble gas, or may be neutral atoms or ions, radical species, or a mixture thereof.

[0079] In some embodiments, the surface activation treatment may include irradiation with electromagnetic waves such as ultraviolet light, laser, etc.

[0080] "Surface activation" refers to a treatment or process performed on surfaces that would not otherwise bond or join when brought into contact, such that the surfaces, when brought into contact with each other after the treatment, result in a desired or substantially effective bond. A laminate formed by bonding substrates after the surface activation treatment may or may not be subjected to heat or light treatment.

[0081] The removal rate of the surface layer may vary depending on the operating conditions of each plasma or beam source, the kinetic energy of the particles, or the irradiation of electromagnetic waves. Therefore, it is necessary to adjust each condition, including the treatment time of the surface activation treatment. For example, the treatment time of the surface activation treatment may be set to the time until the presence of oxygen or carbon in the surface layer can no longer be detected using a surface analysis method such as Auger electron spectroscopy (AES) or X-ray photoelectron spectroscopy (XPS).

[0082] In some embodiments, prior to a surface activation step such as particle beam irradiation, the atmosphere of the substrate is evacuated to a vacuum or ultra-high vacuum, e.g., 10 －５ The pressure is set to a pressure of 10 Pa or less (background pressure). This allows impurities contained in the atmosphere of the substrate to be removed or reduced, and a clean bonding interface to be formed. Generally, the degree of vacuum during the surface activation step is set to a pressure lower than the background pressure, for example, 10 －１ However, since impurities are removed and the activity of the substrate surface does not decrease, the atmosphere can be considered to be in a vacuum state with characteristics equivalent to the background pressure, even though the total pressure has dropped. Therefore, in this specification, the process from surface activation to bonding will be expressed as "without breaking the vacuum" or "activation in a vacuum."

[0083] Surface activation, in some embodiments, may refer to a treatment or step performed on a substrate or thin film after its formation, but in some embodiments, it may not. In some embodiments, surface activation may refer to or include maintaining the bonding surface of the thin film active after the thin film is formed. For example, surface activation may include forming the thin film in a vacuum and bonding the substrate without breaking the vacuum. An active surface may be formed in a vacuum, and the substrates may be bonded while still active.

[0084] The surface on which the thin film material is to be formed may be subjected to surface activation before the thin film is formed, which can, for example, increase the bonding strength between the substrate and the thin film.

[0085] Bonding or laminating the substrates may include contacting the faying surfaces of the substrates with one another, hi some embodiments, bonding or laminating the substrates may include contacting the faying surfaces of surface-activated substrates with one another.

[0086] In some embodiments, surface-activated substrates may be bonded together in a vacuum, which allows the substrates to be bonded together while retaining their activity.

[0087] In some embodiments, the substrate surface may be subjected to a hydrophilization treatment before bonding. In some embodiments, the hydrophilization treatment may be performed as a separate treatment from the activation treatment. For example, the hydrophilization treatment may be performed on the activated surface after the surface activation treatment. In some embodiments, the hydrophilization treatment may be interpreted as part of the surface activation treatment or as part of the surface treatment. Generally, a water component is applied to the substrate after an activation treatment such as particle beam irradiation or plasma irradiation. In some embodiments, the hydrophilization treatment may involve rinsing the substrate with water. In some embodiments, the hydrophilization treatment may involve adding water vapor to the substrate atmosphere. In some embodiments, the hydrophilization treatment may involve lowering the temperature of the substrate to allow water contained in the atmosphere near the substrate surface to condense and adhere to the substrate surface.

[0088] In some embodiments, the hydrophilically treated substrates may be bonded in a vacuum. The water molecules adhering to the substrate surfaces due to the hydrophilic treatment evaporate in the vacuum. Bonding in this state reduces the amount of water remaining at the temporary bonding interface. This reduces the annealing temperature required for sufficient bonding. It also reduces oxidation of the metal regions. Alternatively, it can prevent voids from forming at the bonding interface.

[0089] In some embodiments, when the substrates are brought into contact with each other, force or pressure may be applied to the substrates from the side opposite to the joining surface or from a surface other than the joining surface. By applying pressure, for example, the degree of adhesion at the joining interface can be increased.

[0090] In some embodiments, force or pressure may be applied to the bonding surface or bonding interface. For example, a force perpendicular to the bonding surface may be applied from the outside of the substrates. In some embodiments, the substrates may be pressed or compressed when bonding the substrates. In some embodiments, pressure may be applied so that the force is substantially uniform across the entire contacting bonding surface. In some embodiments, pressure may be applied to different surfaces of the contacting bonding surface at different times. The strength of the force when applying pressure may be constant over time or may be variable. Pressure may be applied to different parts of the bonding surface at different times. Pressure may be applied sequentially to the bonding surface by sliding a pressure device over the contacting substrates. The pressure device may have a roller-shaped pressure unit.

[0091] In the method for bonding substrates included in the present disclosure, from surface activation of the bonding surfaces or thin films on the bonding surfaces to contacting the substrates, from forming a metal oxide layer on the bonding surfaces of the substrates to contacting or bonding the pair of substrates, may be performed consistently in a vacuum or low-pressure atmosphere, or may be performed without breaking the vacuum or low-pressure atmosphere. The vacuum or low-pressure atmosphere refers to an atmosphere in which the background air pressure is at least 10 －５The atmosphere may be 0.1 Pa or lower. Alternatively, during this time, the substrates may be temporarily removed from the vacuum after surface activation. In this case, a dummy substrate may be temporarily bonded to the bonding surfaces to avoid exposing the bonding surfaces to the atmosphere, and after returning to the vacuum, the dummy substrate may be removed and the bonding surfaces may be brought into contact in the vacuum. This may also be included in the term "in a vacuum or low-pressure atmosphere." By performing these steps in a vacuum, adhesion or adsorption of unnecessary substances to the bonding surfaces or oxidation or hydroxylation of the bonding surfaces can be avoided, surface activation can be performed efficiently, the activity of the activated surfaces can be maintained or its decrease can be minimized, and the occurrence of non-bonded areas can be avoided or reduced.

[0092] In some embodiments, the bonded substrates (also referred to in the present disclosure as a bonded body, a substrate stack, etc.) may be subjected to a heat treatment. In some embodiments, the bonded body may be subjected to a heat treatment. In some embodiments, the entire bonded body may be heated. In some embodiments, a reaction may be induced by irradiating the bonded body with light or electromagnetic waves, such as a laser. For example, a heat treatment may be performed after bonding a pair of substrates. After temporary bonding, the heat treatment may be performed to obtain desired bonding characteristics (strength, conductivity, etc.). In this specification, a bond that does not achieve the desired interfacial characteristics is referred to as a "temporary bond." For example, a heat treatment may be performed after temporary bonding. For example, the heat treatment can strengthen the bond between the metal regions.

[0093] In some embodiments, the heat treatment may be performed in an inert atmosphere. The inert atmosphere may be a vacuum, a nitrogen atmosphere, or a rare gas atmosphere such as argon or helium. Oxidation of the thin film material or the material inside the substrate due to the heat treatment may be reduced or avoided. In some embodiments, the heat treatment may be performed in an active atmosphere. For example, the heat treatment may be performed in ozone.

[0094] In some embodiments, the substrates may be pressurized or compressed during the heat treatment. When an external force is applied to the bonding interface, a single-wafer heat treatment is generally performed. For example, the substrate chuck of the bonding apparatus may be equipped with a heater. This allows the bonded body to be heat-treated in the bonding apparatus following the temporary bonding.

[0095] In some embodiments, heat treatment after bonding (temporary bonding) may be performed without pressure or pressure. Heat treatment without applying external force to the bonding interface allows for batch processing, i.e., heat treatment performed on multiple bonded bodies at once. This improves productivity. For example, the temporarily bonded bonded bodies may be removed from the bonding apparatus and introduced into an annealing furnace. Heat treatment can be performed in batches in the annealing furnace. In this specification, pressure-free heat treatment is referred to as "annealing."

[0096] The bonding strength of the bonded body is 2 J / m ２ , 3 J / m ２ , 4 J / m ２ The bonding strength may be higher than the breaking strength of at least one of the pair of substrates.

[0097] In some embodiments, the surfaces of the metal regions may be activated and bonded, and the insulating surfaces may not be bonded. In some embodiments, the surfaces of the metal regions may be activated and bonded, and the insulating surfaces may be bonded. The surfaces of the insulating surfaces may also be activated.

[0098] The joining method according to some embodiments of the present disclosure is useful for Cu-Cu hybrid joining, which refers to a technique or method for joining a pair of joining surfaces, each of which has a metal element for electrical connection, such as copper, and an insulator element, such as an oxide.

[0099] In conventional hybrid bonding, the substrate surfaces are subjected to plasma treatment and hydrophilic treatment, and then the substrates are temporarily bonded in the atmosphere. This bonds the insulating surfaces together. The metals are then bonded together by annealing. With this method, water molecules are present at the bonding interface during temporary bonding. Therefore, in order to bond the metals together, annealing at high temperatures, for example, 350 to 400 degrees Celsius (hereinafter referred to as "°C"), is required.

[0100] In contrast, in some embodiments of the present disclosure, the background is ultra-high vacuum (e.g., 10 －５Alternatively, the substrates may be temporarily bonded in a vacuum, followed by surface activation treatment using ion bombardment or atomic beam irradiation at a pressure of 100 Pa or less, followed by hydrophilization treatment (e.g., application of water vapor in the same chamber). Introducing the hydrophilized substrates into a vacuum evaporates the water on the substrate surfaces. The inventors have found that bonding the substrates after this, i.e., in a vacuum, allows for sufficient bonding even when the temperature for the subsequent annealing is reduced to 200°C or less. This method has been found to be preferable to conventional hybrid bonding.

[0101] Conventionally, the bonding strength of the insulating surface was maintained and Cu was diffusion bonded by annealing at 400°C. In contrast, with this method, it is not necessary to ensure strength by bonding the insulating surface, and it is possible to ensure both the conductivity and mechanical strength of Cu by bonding the Cu-Cu electrodes. Furthermore, strength can be further improved by bonding dummy pads. Therefore, strong bonding of the insulating surface is no longer necessary.

[0102] Furthermore, in some embodiments of the present disclosure, the background is ultra-high vacuum (e.g., 10 －５ Alternatively, the substrates may be temporarily bonded in a vacuum without hydrophilization treatment by surface activation treatment using ion bombardment or atomic beam irradiation at a pressure of 100 Pa or less. Furthermore, annealing may be performed after this temporary bonding. The inventors have found that this allows the annealing temperature to be reduced to 200°C or less. Furthermore, the inventors have found that sufficient bonding is possible even when the annealing temperature is reduced to 150°C or less. This method has been found to be preferable to conventional hybrid bonding.

[0103] Conventionally, the bonding strength of the insulating surface was maintained and Cu was diffusion bonded by annealing at 400°C. In contrast, with this method, it is possible to ensure both the conductivity and mechanical strength of Cu by directly bonding the Cu-Cu electrodes. Furthermore, strength can be further improved by bonding dummy pads. Therefore, bonding of the insulating surface is no longer necessary. In this specification, "direct bonding" refers to a bonding interface that bonds the atoms of the two parts to be bonded (for example, both metal regions) without the intervention of hydroxyl groups, water, solder, alloys, etc.

[0104] Bonding by Heating In some embodiments, surface activation may not be necessary. For example, the substrates may be brought into contact with each other and heated while in contact. Heating removes oxides or impurities present on the surface of the metal regions, allowing the metal to directly contact the other metal and form a strong bond. Even if the surfaces are activated, heat may be applied after contact or bonding.

[0105] <Low-Temperature Bonding Method> For example, as shown in FIG. 2, during bonding, the insulator may contact an insulator or a metal region of another substrate. In some embodiments, the insulator and the metal region may contact simultaneously. For example, as shown in FIG. 1, a substrate may be used in which the metal region protrudes from the insulating surface. Even if a portion of the metal region contacts the other substrate, a sufficient electrical and / or mechanical bond is not formed. However, a portion of the insulator may contact and bond with the other substrate. If the insulator has high surface activity, bonding of the insulator occurs first, increasing the bonding area. This applies pressure to the surface of the protruding metal region, compressing the metal region. This allows for strong bonding of the metal region. In some embodiments, the insulator may contact the other substrate first, and then the metal region may contact or bond thereto substantially later. In some embodiments, the insulator may contact the other substrate first, and then the metal region may contact or bond thereto substantially later.

[0106] The surface of the insulating surface may be, for example, a fluorinated oxide, a compound containing Si—O—F, or the like. Fluorination may be performed by exposure to a fluorine-containing liquid, vapor, or gas, or by introducing fluorine by ion implantation. The surface may further be treated with NH ２ The surface may be terminated with, for example, an NH group at the interface. ４ By these treatments, the insulating surface, for example, the oxide surface, can obtain a high bonding strength at a relatively low temperature (such as room temperature).

[0107] 3. Signal Transmission Characteristics Figure 10 shows the structure of the substrate assembly 1000 used in the simulation. The substrate assembly 1000 consists of three layers, and each layer has a plain ground (ground metal region) and a signal transmission pad on its top and bottom surfaces. The layers are connected by ground TSVs and signal TSVs. This model is configured to have a 50 Ω transmission line.

[0108] Figure 11 shows the signal pass and reflection characteristics for the model shown in Figure 10. The horizontal axis represents the signal frequency (megahertz, MHz), and the vertical axis represents the signal strength (decibels, dB). Resonances thought to be caused by pad impedance mismatch are visible. That is, as the signal repeatedly reflects between pads via the TSV, the pass characteristics attenuate and the reflection characteristics increase, causing a steep frequency disturbance. The frequency of the primary reflection is determined by the length of each TSV. Frequencies close to 20 GHz are thought to be the frequency of the secondary resonance mode. It is possible to reduce these resonances. For example, the thickness of the substrate can be reduced and the length of the TSV can be shortened. This allows the resonance frequency corresponding to the TSV length to be shifted higher. This result indicates that good pass characteristics can be obtained up to high frequencies (e.g., around 20 GHz).

[0109] Further embodiments and examples are described below.

[0110] <Wiring Metal Region> In some embodiments, the bonding surface may have wiring (also referred to as a wiring metal region) arranged along the bonding surface. In some embodiments, the wiring metal region may be bonded to another substrate. In some embodiments, a first bonding surface of a first substrate may have a first wiring metal region, and a second bonding surface of a second substrate bonded to the first substrate may have a second wiring metal region. The first wiring region and the second wiring metal region may be bonded.

[0111] The wiring metal region may be configured so that an electrical signal or current flows in a direction toward the connection surface in a part, at least a part, or the entirety of the wiring metal region. The wiring metal region may be connected to a through electrode that penetrates the substrate.

[0112] In some embodiments, the first wiring metal region of the first substrate and the second wiring metal region of the second substrate may have substantially the same shape and be joined over substantially their entire areas, while in some embodiments, the first wiring metal region of the first substrate and the second wiring metal region of the second substrate may have different shapes or may be configured to not overlap in part.

[0113] In some embodiments, the first wiring metal region of the first substrate and the second wiring metal region of the second substrate may be bonded to form wiring along the bonding surface. A first through-hole electrode of the first substrate may be connected to a portion of this formed wiring, and a second through-hole electrode of the second substrate may be connected to another portion of this formed wiring. In this case, an electrical signal or current may be transmitted from the first through-hole electrode to the wiring formed in the bonding surface and then to the second through-hole electrode, or vice versa.

[0114] As a non-limiting example, bonding of wiring metal regions at the bonding surface improves the strength of the bonded body. As a non-limiting example, bonding of wiring metal regions at the bonding surface improves the electrical properties of the bonded body. In three-dimensional packaging, a layout is adopted in which wiring is arranged in an in-plane direction depending on the arrangement of elements in the planar direction and / or three-dimensional direction, the configuration of the wiring between them, etc. By bonding such wiring, bonding properties such as mechanical strength and electrical properties can be improved. In-plane wiring can be used effectively.

[0115] In some embodiments, the bonding surface may have wiring metal regions and plain metal regions (plain metal regions). In some embodiments, the substrate may have plain metal regions within the substrate (below the bonding surface).

[0116] <Examples of Wiring Metal Regions> Figures 12 to 16 show schematic examples of bonded substrates having wiring metal regions. (A) in each figure shows a perspective view of the bonded structure as viewed from a direction perpendicular to the bonded surface. (B) in each figure shows a perspective view of the bonded structure. Portions other than the metal region, such as non-metallic regions, insulating portions, and dielectrics, are shown as transparent. The noise blocking characteristics of these models were simulated (see Figure 21).

[0117] In the example of FIG. 12 (L8 um w / o PL), the longitudinal length of the wiring metal region is 8 μm (L8 um), and no plain metal region is provided (w / o PL).

[0118] A first substrate 2110 and a second substrate 2120 are bonded at a bonding surface 2150. The first substrate 2110 has, on its bonding surface, a long and narrow wiring metal region for signal transmission (first signal transmission wiring metal region) 2111, a ground wiring metal region (first ground wiring metal region) 2113 connected to ground, and a power wiring metal region (first power supply wiring metal region) 2115 connected to power. These wiring regions 2111, 2113, and 2115 are arranged in an array on the bonding surface. One end of the first signal transmission wiring metal region 2111 is connected to a signal transmission through electrode (first signal transmission through electrode) 2112. One end of the first ground wiring metal region 2113 is connected to a ground through electrode (first ground through electrode) 2114. One end of the first power supply wiring metal region 2115 is connected to a power supply through electrode (first power supply through electrode) 2116.

[0119] The second substrate 2120 is configured in substantially the same manner as the first substrate 2110. The second substrate 2120 has, on its bonding surface, a long and narrow wiring metal region for signal transmission (second signal transmission wiring metal region) 2121, a wiring metal region for ground connected to ground (second ground wiring metal region) 2123, and a wiring metal region for power supply connected to power supply (second power supply wiring metal region) 2125. The through electrodes in the second substrate 2120, i.e., the second signal transmission through electrode 2122, the second ground through electrode 2124, and the second power supply through electrode 2126, are also configured in the same manner as the first signal transmission through electrode 2112, the first ground through electrode 2114, and the first power supply through electrode 2116 of the first substrate 2110.

[0120] The first signal transmission wiring metal region 2111, the first ground wiring metal region 2113, and the first power supply wiring metal region 2115 of the first substrate 2110 are bonded to the second signal transmission wiring metal region 2121, the second ground wiring metal region 2123, and the second power supply wiring metal region 2125 of the second substrate 2120, respectively. This electrically connects the first signal transmission through electrode 2112, the first signal transmission wiring metal region 2111, the second signal transmission wiring metal region 2121, and the second signal transmission through electrode 2122. The first signal transmission through electrode 2112, the first signal transmission wiring metal region 2111, the second signal transmission wiring metal region 2121, and the second signal transmission through electrode 2122 are electrically connected. The first ground through electrode 2114, the first ground wiring metal region 2113, the first signal transmission wiring metal region 2111, the second signal transmission wiring metal region 2121, and the second signal transmission through electrode 2122 are electrically connected.

[0121] In the example shown in Figure 13 (L8um PPG), the longitudinal length of the wiring metal region was 8µm (L8um). Furthermore, power plane metal regions connected to the power supply were provided on the bonding surfaces of both substrates, and these were bonded together, with a ground plane metal region provided in one of the substrates (PPG).

[0122] A first substrate 2210 and a second substrate 2220 are bonded at a bonding surface 2250. The first substrate 2210 has a first signal transmission wiring metal region 2211, a first ground wiring metal region 2213, and a first power supply wiring metal region 2215 on the bonding surface. These wiring regions 2211, 2213, and 2215 are arranged in an array on the bonding surface, and a power supply plane metal region 2215P connected to the power supply and the first power supply wiring metal region 2215 is arranged to surround them.

[0123] The second substrate 2220 has a second signal transmission wiring metal region 2221, a second ground wiring metal region 2223, and a second power supply wiring metal region 2225 on its bonding surface. These wiring regions 2221, 2223, and 2225 are arranged in an array on the bonding surface, and a power supply plane metal region 2225P connected to the power supply and second power supply wiring metal region 2225 is arranged surrounding them. The second substrate 2220 of FIG. 13 further has a ground plane metal region 2223P arranged within the substrate (below the bonding surface) and parallel to the bonding surface. The ground plane metal region 2223P is electrically connected to the ground and second ground wiring metal region 2223.

[0124] The first signal transmission wiring metal region 2211, the first ground wiring metal region 2213, the first power supply wiring metal region 2215, and the first power supply plane metal region 2215P of the first substrate 2210 are bonded to the second signal transmission wiring metal region 2211, the second ground wiring metal region 2223, the second power supply wiring metal region 2225, and the first power supply plane metal region 2225P of the second substrate 2220, respectively.

[0125] The through electrodes are also arranged and connected to the corresponding metal regions in the same manner as in Fig. 12, and a description thereof will be omitted. Note that the power supply wiring metal region and the power supply plane metal region on the joining surface are formed substantially flush with each other, and do not necessarily need to be distinguished.

[0126] In the example shown in Figure 14 (L8um GPPG), the longitudinal length of the wiring metal region was 8µm (L8um). Furthermore, power plane metal regions connected to the power supply were provided on the bonding surfaces of both substrates, and these were bonded together, and ground plane metal regions were provided within both substrates (below the bonding surfaces) (GPPG).

[0127] A first substrate 2310 and a second substrate 2320 are bonded at a bonding surface 2350. The first substrate 2310 has a first signal transmission wiring metal region 2311, a first ground wiring metal region 2313, and a first power supply wiring metal region 2315 on the bonding surface. These wiring regions 2311, 2313, and 2315 are arranged in an array on the bonding surface, and a power supply plane metal region 2315P connected to the power supply and the first power supply wiring metal region 2315 is arranged surrounding them. The first substrate 2310 in FIG. 14 further has a ground plane metal region 2313P arranged parallel to the bonding surface within the substrate (below the bonding surface). The ground plane metal region 2313P is electrically connected to the ground and the first ground wiring metal region 2313.

[0128] The second substrate 2320 has a second signal transmission wiring metal region 2321, a second ground wiring metal region 2323, and a second power supply wiring metal region 2325 on its bonding surface. These wiring regions 2321, 2323, and 2325 are arranged in an array on the bonding surface, and a second power supply plane metal region 2325P connected to the power supply and second power supply wiring metal region 2325 is arranged surrounding them. The second substrate 2320 in FIG. 14 also has a ground plane metal region 2323P arranged within the substrate (below the bonding surface) and parallel to the bonding surface. The ground plane metal region 2323P is electrically connected to the ground and second ground wiring metal region 2323.

[0129] The first signal transmission wiring metal region 2311, the first ground wiring metal region 2313, the first power supply wiring metal region 2315, and the first power supply plane metal region 2315P of the first substrate 2310 are bonded to the second signal transmission wiring metal region 2311, the second ground wiring metal region 2323, the second power supply wiring metal region 2325, and the second power supply plane metal region 2325P of the second substrate 2320, respectively.

[0130] The through electrodes are also arranged and connected to the corresponding metal regions in the same manner as in Fig. 12, and a description thereof will be omitted. Note that the power supply wiring metal region and the power supply plane metal region on the joining surface are formed substantially flush with each other, and do not necessarily need to be distinguished.

[0131] In the example (L8um GG) in Fig. 15, the length of the wiring metal region in the longitudinal direction was 8µm (L8um). Furthermore, a ground plane metal region connected to ground was provided on the bonding surfaces of both substrates (GG).

[0132] The first substrate 2410 and the second substrate 2420 are bonded at a bonding surface 2450. The first substrate 2410 has a first signal transmission wiring metal region 2411 and a first ground wiring metal region 2413 on the bonding surface. These wiring regions 2311, 2313 are arranged in an array on the bonding surface. One unit 2460 is configured to include three first signal transmission wiring metal regions 2411 and one first ground wiring metal region 2413. The bonding surface further has a first ground plane metal region 2413P, which surrounds the two first signal transmission wiring metal regions 2411 and one first signal transmission wiring metal region 2411 in the unit 2460, respectively, and is connected to the ground and first ground wiring metal region 2413.

[0133] The second substrate 2420 has, on its bonding surface, a second signal transmission wiring metal region 2421 and a second ground wiring metal region 2423. These wiring regions 2421, 2423 are arranged in an array on the bonding surface, and a ground plane metal region 2423P connected to the ground and the first ground wiring metal region 2423 is arranged so as to surround them.

[0134] The first signal transmission wiring metal region 2411, the first ground wiring metal region 2413, and the first ground plane metal region 2413P of the first substrate 2410 are bonded to the second signal transmission wiring metal region 2421, the second ground wiring metal region 2423, and the second ground plane metal region 2423P of the second substrate 2420, respectively.

[0135] The through electrodes are also arranged and connected to the corresponding metal regions in the same manner as in Fig. 12, and a description thereof will be omitted. Note that the ground wiring metal region and the ground plane metal region on the bonding surface are formed substantially flush with each other, and do not necessarily need to be distinguished.

[0136] In the example shown in Fig. 16 (L8um PGGP), the longitudinal length of the wiring metal region was 8µm (L8um). Furthermore, ground plane metal regions connected to the power supply were provided on the bonding surfaces of both substrates, and these were bonded together, with power plane metal regions provided within both substrates (below the bonding surfaces) (PGGP).

[0137] A first substrate 2510 and a second substrate 2520 are bonded at a bonding surface 2550. The first substrate 2510 has a first signal transmission wiring metal region 2511, a first ground wiring metal region 2513, and a first power supply wiring metal region 2515 on the bonding surface. These wiring regions 2511, 2513, and 2515 are arranged in an array on the bonding surface, and a first ground plane metal region 2513P connected to the ground and first ground wiring metal region 2513 is arranged surrounding them. The first substrate 2510 of FIG. 16 further has a first power supply plane metal region 2515P arranged parallel to the bonding surface within the substrate (below the bonding surface). The first power supply plane metal region 2515P is electrically connected to the power supply and first power supply wiring metal region 2515.

[0138] The second substrate 2520 is configured symmetrically to the first substrate 2510. The second substrate 2520 has a second signal transmission wiring metal region 2521, a second ground wiring metal region 2523, and a second power supply wiring metal region 2525 on its bonding surface. These wiring regions 2521, 2523, and 2525 are arranged in an array on the bonding surface, and a second ground plane metal region 2523P connected to the ground and second ground wiring metal region 2523 is arranged surrounding them. The second substrate 2520 in FIG. 16 further has a second power supply plane metal region 2525P arranged parallel to the bonding surface within the substrate (below the bonding surface). The second power supply plane metal region 2525P is electrically connected to the power supply and first power supply wiring metal region 2515.

[0139] The first signal transmission wiring metal region 2511, the first ground wiring metal region 2513, the first power supply wiring metal region 2515, and the first ground plane metal region 2515P of the first substrate 2510 are bonded to the second signal transmission wiring metal region 2511, the second ground wiring metal region 2523, the second power supply wiring metal region 2525, and the second ground plane metal region 2525P of the second substrate 2520, respectively.

[0140] The through electrodes are also arranged and connected to the corresponding metal regions in the same manner as in Fig. 12, and a description thereof will be omitted. Note that the ground wiring metal region and the ground plane metal region on the bonding surface are formed substantially flush with each other, and do not necessarily need to be distinguished.

[0141] <Examples without wiring metal regions> Figures 17 to 20 show schematic examples of standard bonded substrates (bonding surfaces without wiring metal regions). (A) in each figure shows a perspective view of the bonded surface of the bonded body as viewed from a direction perpendicular to the bonded surface. (B) in each figure shows a perspective view of the bonded body. Portions other than the metal regions, such as non-metallic regions, insulating parts, and dielectrics, are shown as transparent. The noise blocking characteristics of these models were simulated (see Figure 21).

[0142] In some embodiments, the metal regions (or metal pads) for differential signals, i.e., a signal plus metal region and a signal minus metal region, may be arranged in a unit on the mating surface, and the unit may be arranged in an array. The differential signal metal regions may be arranged in an array on the mating surface. The unit may include a single-ended metal region. The unit may include a ground metal region.

[0143] In some embodiments, a ground metal region may be disposed within the mating surface of the unit to surround the differential signal metal region, and the ground metal region may have an opening in the mating surface within which other metal regions may be disposed.

[0144] In some embodiments, one opening may contain only one of the differential signal plus metal region and the differential signal plus metal region. For example, one opening may contain only the differential signal plus metal region and the other opening contains only the differential signal minus metal region. For example, another opening may be provided on the mating surface, and a single-ended metal region may be disposed within that opening.

[0145] In some embodiments, only one pair of differential signal plus metal regions may be disposed in one opening, where the differential signal plus metal regions and the differential signal plus metal regions are separated from each other by an insulating surface, but only one pair of differential signal plus metal regions, i.e., two metal regions (pads), are disposed in the opening.

[0146] In some embodiments, one opening may contain only one pair of differential signal plus metal regions and other metal regions. The differential signal plus metal regions and the differential signal plus metal regions are separated from each other by an insulating surface within the opening, and only one pair of differential signal plus metal regions and other metal regions may be disposed within the opening. The other metal regions may be, for example, single-ended metal regions.

[0147] The examples shown in Figures 17 to 20 are described below as non-limiting examples thereof.

[0148] In the example shown in Figure 17 (STD SE w / o PL), the standard model (STD) does not include wiring metal areas. The bonding surface has electrode pads (metal areas), and the electrode pads have metal areas for differential signals and single-ended metal areas (SE). No plane metal areas were provided (w / o PL).

[0149] A first substrate 2610 and a second substrate 2620 are bonded at a bonding surface 2650. The first substrate 2610 has a first differential signal plus metal region 2611+, a first differential signal minus metal region 2611-, a first single-ended metal region 2611se, and a first ground metal region 2613 on the bonding surface. FIG. 17 shows the arrangement of units 2660 within the bonding surface. A pair of differential signal metal regions 2611+, 2611-, a first single-ended metal region 2611se, and a first ground metal region 2613 are arranged within the bonding surface of the unit 2660. The units 2660 are repeatedly arranged in the bonding surface direction, and the differential signal metal regions 2611+, 2611-, the first single-ended metal region 2611se, and the first ground metal region 2613 are arranged in an array on the bonding surface.

[0150] The second substrate 2620 is configured symmetrically to the first substrate 2610. The second substrate 2620 has, on its joining surface, a second differential signal plus metal region 2621+, a second differential signal minus metal region 2621-, a second single-ended metal region 2621se, and a second ground metal region 2623. These metal regions 2621+, 2621-, 2621se, and 2623 are arranged in an array on the joining surface.

[0151] The first differential signal plus metal region 2611+, the first differential signal minus metal region 2611-, the first single-ended metal region 2611se, and the first ground metal region 2613 of the first substrate 2610 are bonded to the second differential signal plus metal region 2621+, the second differential signal minus metal region 2621-, the second single-ended metal region 2621se, and the second ground metal region 2623 of the second substrate 2620, respectively.

[0152] 17, the through electrodes penetrating the substrate and the metal regions disposed on the bonding surface are not distinguished from each other, but they may be distinguished and may be formed or defined separately.

[0153] The example in Figure 18 (STD SE GG) is a standard model (STD) that does not include wiring metal areas. The joining surfaces have electrode pads (metal areas), and the electrode pads have metal areas for differential signals and single-ended metal areas (SE). Furthermore, ground plane metal areas connected to ground are provided on the joining surfaces of both substrates, and these are joined together (GG).

[0154] A first substrate 2710 and a second substrate 2720 are bonded at a bonding surface 2750. The first substrate 2710 has a first differential signal plus metal region 2711+, a first differential signal minus metal region 2711-, a first single-ended metal region 2711se, and a first ground metal region 2713 on the bonding surface. FIG. 18 shows the arrangement of a unit 2760 within the bonding surface. A pair of differential signal metal regions 2711+, 2711-, and one first single-ended metal region 2711se are arranged within the bonding surface of the unit 2760, spaced apart from each other by an insulating surface, and a first ground plane metal region 2713P connected to ground and the first ground metal region 2713 is arranged to surround all three of these. In other words, the first ground plane metal region 2713P has an opening that is free of metal, and the first ground plane metal region 2713P connected to ground and the first ground metal region 2713 is arranged within the opening. The units 2760 are repeatedly arranged in the joining surface direction, and the differential signal metal regions 2711+, 2711-, the first single-ended metal region 2711se, and the first ground metal region 2713 are arranged in an array on the joining surface.

[0155] The pad spacing was 1 μm, and the distance from one side of the pad to the nearest ground plane metal area was 0.5 μm.

[0156] The second substrate 2720 is configured symmetrically to the first substrate 2710. Therefore, a description of the second substrate 2720 will be omitted.

[0157] The first differential signal plus metal region 2711+, the first differential signal minus metal region 2711-, the first single-ended metal region 2711se, the first ground metal region 2713, and the first ground plane metal region 2713P of the first substrate 2710 are bonded to the second differential signal plus metal region 2721+, the second differential signal minus metal region 2721-, the second single-ended metal region 2721se, the second ground metal region 2723, and the second ground plane metal region 2723P of the second substrate 2720, respectively.

[0158] In the example of FIG. 18, the ground metal region and the ground plane metal region on the joining surface are formed substantially flush with each other, and do not necessarily need to be distinguished.

[0159] The example in Figure 19 (STD SE GG 025) is a standard model (STD) that does not include wiring metal areas. The bonding surface has electrode pads (metal areas), which have metal areas for differential signals and single-ended metal areas (SE). Furthermore, ground plane metal areas connected to ground were provided on the bonding surfaces of both substrates (GG). Furthermore, the distance from one side of the pad to the nearest ground plane metal area was 0.25 μm (025).

[0160] A first substrate 2810 and a second substrate 2820 are bonded at a bonding surface 2850. The first substrate 2810 has a first differential signal plus metal region 2811+, a first differential signal minus metal region 2811-, a first single-ended metal region 2811se, and a first ground metal region 2813 on the bonding surface. FIG. 19 shows the layout within a unit 2860. A first ground plane metal region 2813P connected to ground and the first ground metal region 2813 is arranged to surround each of the first differential signal plus metal region 2811+, the first differential signal minus metal region 2811-, and the first single-ended metal region 2811se. In other words, the first ground plane metal region 2813P has three openings within the unit, with one metal region arranged in each opening. That is, a first differential signal plus metal region 2811+ is disposed within the first opening, a first differential signal minus metal region 2811- is disposed within the second opening, and a first single-ended metal region 2811se is disposed within the third opening. Units 2860 are repeatedly disposed in the joining surface direction, and these differential signal plus and minus metal regions 2811+, 2811-, first single-ended metal region 2811se, and first ground metal region 2813 are arranged in an array on the joining surface.

[0161] The pad spacing was 1 μm, and the distance from one side of the pad to the nearest ground plane metal area was 0.25 μm.

[0162] In the "STD SE GG" example of FIG. 18, the first ground plane metal region 2713P is arranged to surround the first differential signal plus metal region 2811+, the first differential signal minus metal region 2811-, and the first single-ended metal region 2811se. In contrast, in the "STD SE GG025" example of FIG. 19, the first ground plane metal region 2813P is arranged to surround each of the first differential signal plus metal region 2811+, the first differential signal minus metal region 2811-, and the first single-ended metal region 2811se. In both examples, the pad size and the distance between pads were set to the same. However, the distance from one side of the pad to the nearest ground plane metal region was set to 0.5 μm and 0.25 μm, respectively. Therefore, the manner in which the ground plane metal region surrounds the pad differs between the two.

[0163] The second substrate 2820 is configured symmetrically to the first substrate 2810. Therefore, a description of the second substrate 2820 will be omitted.

[0164] The first differential signal plus metal region 2811+, the first differential signal minus metal region 2811-, the first single-ended metal region 2811se, the first ground metal region 2813, and the first ground plane metal region 2813P of the first substrate 2810 are bonded to the second differential signal plus metal region 2821+, the second differential signal minus metal region 2821-, the second single-ended metal region 2821se, the second ground metal region 2823, and the second ground plane metal region 2823P of the second substrate 2820, respectively.

[0165] In the example of FIG. 19, the ground metal region and the ground plane metal region on the joining surface are formed substantially flush with each other, and do not necessarily need to be distinguished.

[0166] The example in Figure 20 (STD PGGP) is a standard model (STD) that does not include wiring metal areas. The bonding surface has electrode pads (metal areas), and the electrode pads have metal areas for differential signals, power pins, and ground. Furthermore, ground plane metal areas connected to ground are provided on the bonding surfaces of both substrates, and these are bonded together, with power plane metal areas provided within both substrates (below the bonding surfaces) (PGGP).

[0167] A first substrate 2910 and a second substrate 2920 are bonded at a bonding surface 2950. The first substrate 2910 has a first differential signal plus metal region 2911+, a first differential signal minus metal region 2911-, a first power supply metal region (also called a power supply pin) 2915, and a first ground metal region 2913 on the bonding surface. FIG. 20 shows the internal arrangement of a unit 2960. A pair of differential signal metal regions 2911+, 2911- are arranged on the bonding surface of the unit 2960, spaced apart from each other by an insulating surface, and a first ground plane metal region 2913P, connected to ground and the first ground metal region 2913, is arranged surrounding these two. In other words, the first ground plane metal region 2913P has an opening that is free of metal, and the pair of differential signal metal regions 2911+, 2911- are arranged within the opening. 20 further includes a first power plane metal region 2915P disposed within the substrate (below the bonding surface) and parallel to the bonding surface. The first power plane metal region 2915P is electrically connected to the power supply and first power wiring metal region 2915. The bonding surface includes an array of differential signal metal regions 2911+, 2911-, and first power plane metal region 2915 and first ground metal region 2913, which are connected to ground plane metal region 2913P.

[0168] The pad spacing was 1 μm, and the distance from one side of the pad to the nearest ground plane metal area was 0.5 μm.

[0169] The second substrate 2920 is configured symmetrically to the first substrate 2910. Therefore, a description of the second substrate 2920 will be omitted.

[0170] The first differential signal plus metal region 2911+, the first differential signal minus metal region 2911−, the first power supply metal region 2915, the first ground metal region 2913, and the first ground plane metal region 2913P of the first substrate 2910 are bonded to the second differential signal plus metal region 2921+, the second differential signal minus metal region 2921−, the second power supply metal region 2925, the second ground metal region 2923, and the second ground plane metal region 2923P of the second substrate 2920, respectively.

[0171] In the example of FIG. 20, the ground metal region and the ground plane metal region on the joining surface are formed substantially flush with each other, and do not necessarily need to be distinguished.

[0172] <Simulation of Noise Transmission> For each of the models shown in Figures 12 to 20, calculation units 2160, 2260, 2360, 2460, 2560, 2660, 2760, 2860, and 2960 were set. As a noise source model, these units were irradiated with electromagnetic waves parallel to the bonding surface (parallel waves) in a direction perpendicular to the bonding surface. Figure 21 shows the transmission characteristics when the frequency of the parallel waves was 20 GHz to 100 GHz.

[0173] For the simulation, CST STUDIO SUITE was used, and the signal transmission characteristics were calculated using S parameters (particularly, transmission loss using S21 and the influence of crosstalk using S41). The noise shielding effect was evaluated by regarding noise as a plane wave and irradiating a plane wave (TE (0,0) wave) perpendicularly to the joint surface using S parameter.

[0174] <Effect of Plain Metal Areas on Noise Transmission Suppression> Figure 21 shows the noise transmission characteristics of the models shown in Figures 12 to 20. It was revealed that, as a general trend, plain metal areas have the effect of suppressing noise transmission. Comparing five "L8um" models with wiring electrodes, noise transmission was suppressed in the following order: "w / o PL" (no plain metal area), "PP" (two bonded plain metal areas), "PPG" (two bonded plain metal areas and a buried plain metal area), "PGGP" and "GPPG" (two bonded plain metal areas and two plain metal areas buried in each substrate). Comparing three "STD" models without wiring electrodes with the same spacing between the pads and plain metal areas, noise transmission was suppressed in the following order: "w / o PL," "GG," and "PGGP." Therefore, it was first revealed that plain metal areas have the effect of suppressing noise transmission compared to configurations without plain metal areas. Second, the greater the number or thickness of the plain metal areas, the greater the effect of noise transmission suppression.

[0175] A bonded body may have one or more (two, three, four, five, or more) plain metal regions in at least two substrates. For example, the plain metal region may be located on the joining surface of one of the two bonded substrates. The plain metal region may be located inside one of the two bonded substrates. For example, a bonded body may have two plain metal regions. Two plain metal regions may be located on the joining surface of the two bonded substrates. These may be bonded to each other. One of the two plain metal regions may be located on the joining surface of one of the two bonded substrates, or may be located inside the substrate. The multiple plain metal regions may be located perpendicular to the joining surface on either or both of the joining surface and inside the substrate (below the joining surface).

[0176] Furthermore, since no difference was observed between "PGGP" and "GPPG" in the results of Figure 21, it can be said that the plane metal area has approximately the same level of effect whether it is connected to a power supply or to ground.

[0177] <Effect of the distance between the pad and the plain metal area> Furthermore, when comparing "STD SE GG" (with a distance of 0.5 μm between the pad and the plain metal area) with "STD SE GG 025" (with a distance of 0.25 μm), the latter suppressed noise transmission more effectively. This means that the larger the area of ​​the plain metal area, the greater the effect of noise transmission suppression. Alternatively, when viewed perpendicular to the bonding surface, the larger the metal area, the greater the effect of noise transmission suppression.

[0178] Furthermore, simulations were performed using the units shown in Figures 22(A) to 22(C). The example in Figure 22(A) (L8um GG), the example in Figure 22(B) (L8um PGGP), and the example in Figure 22(C) (L8um GPPG) correspond to the examples in Figures 15, 16, and 14, respectively. For each configuration, the gap g shown in the figure was set to 0.25 μm and 0.5 μm.

[0179] Each figure shows a perspective view of the bonded body viewed from a direction perpendicular to the bonded surface. Non-metallic areas, insulating parts, dielectrics, and other non-metallic areas are shown as transparent. To investigate the effect of the gap between the metallic area and the plain metallic area on the noise blocking characteristics, two gaps were used for each model, and the noise blocking characteristics for each were simulated (see Figure 25).

[0180] As a noise source model, a parallel wave parallel to the bonding surface was irradiated to these units in a direction perpendicular to the bonding surface. The parallel wave had a frequency of 20 GHz to 100 GHz. The simulation conditions were the same as those shown above.

[0181] The noise transmission characteristics for each model are shown in Figure 23. It was clear that for all configurations, "L8um GG," "L8um PGGP," and "L8um GPPG," the smaller the gap, the greater the effect of noise transmission suppression.

[0182] As shown in Figures 21 and 23, a gap of 0.25 μm was found to have a higher noise transmission suppression effect than a gap of 0.5 μm. This means that the larger the area of ​​the plain metal region, the higher the noise transmission suppression effect. Alternatively, when viewed perpendicularly to the bonding surface, the larger the metal region, the higher the noise transmission suppression effect.

[0183] It is generally believed that a gap larger than 0.5 μm can provide a noise transmission suppression effect. For example, a gap of 1 μm is also considered to provide a high effect. The gap may be determined according to the circuit design. In other words, 0.25 μm, for example, is not necessarily optimal in terms of design selection of the circuit or the entire unit. A gap of 0.5 μm, 1 μm, or the like can also provide a noise transmission suppression effect.

[0184] <Effects of Plain Metal Areas on Crosstalk> We simulated the crosstalk between the plus and minus differential signals of "STD SE w / o PL" and "STD SE GG." At 50 GHz, "STD SE w / o PL" showed -64 dB, and "STD SE GG" showed -67 dB. Therefore, although there were some differences in the values, there was essentially no difference. Although it depends on the design of the layout of elements inside and outside the junction, and the placement of wiring, it is possible to suppress the adverse effects of plain metal areas on the signal transmission characteristics by adopting an appropriate design.

[0185] <Metal Region as High-Frequency Noise Countermeasure> The bonded body may include a high-frequency module, device, unit, or element (hereinafter, may be referred to as a high-frequency element). The metal region may have a function of suppressing transmission of high-frequency noise emitted from the high-frequency element.

[0186] Examples of high-frequency elements include, but are not limited to, Si or compound semiconductor high-frequency elements. Si high-frequency elements generally function in the band of several MHz to several GHz. Examples of high-frequency elements include, but are not limited to, clock generators, RF elements, etc. III-V high-frequency elements such as GaAs, GaN, and InP generally function in bands such as 1 GHz, 10 GHz, and 100 GHz. Examples of high-frequency elements include, but are not limited to, bipolar transistors (BTs) such as heterojunction bipolar transistors (HBTs); and field-effect transistors (FETs) such as MOSFETs and FinFETs.

[0187] The bonded assembly may have a metal region of a predetermined area or larger above or below the high-frequency element. This suppresses the transmission of high-frequency noise emitted from the high-frequency element and limits its influence on other elements, signal transmission, and other electrical characteristics. The metal region corresponding to the RF element may be positioned parallel to the bonding surface at a position perpendicular to the bonding surface (the stacking direction in three-dimensional packaging).

[0188] When viewed perpendicularly to the bonding surface, the metal region may cover a predetermined percentage or a larger percentage of the area occupied by the high-frequency element. The metal region may include a plain metal region. The metal region may include a wiring electrode parallel to the bonding surface. The metal region, plain metal region, and wiring electrode may be disposed on a certain bonding surface or may be disposed below the bonding surface (inside the substrate).

[0189] The metal region may be arranged on one bonding surface or on a plane within one substrate. A metal region having the function of suppressing transmission of noise emitted from the high-frequency element may be provided on one bonding surface. However, the metal region may be formed in multiple layers. The metal regions may be arranged with the same size on multiple layers. However, the metal regions may be arranged with different sizes on multiple layers. The arrangement of the metal regions may be arranged depending on the design of each substrate or layer. The metal regions may be arranged on multiple bonding surfaces, on multiple planes within the substrates, or on multiple bonding surfaces and planes within the substrates, and may be arranged so that their total area, when viewed in a direction perpendicular to the bonding surfaces, is a predetermined percentage or greater of the area occupied by the high-frequency element.

[0190] <Effect of Area Ratio of Metal Region> To investigate the effect of the area of ​​the metal region on suppressing noise transmission, a simulation was performed using the model shown in Figure 24. The left side of Figures 24(A) to (D) shows a perspective view of the assembly unit as viewed from a direction perpendicular to the joining surface. The right side shows a perspective view of the assembly. The explanation of the arrangement in the figures is omitted as it is the same as in Figures 12 to 20.

[0191] Figure 24(C) shows a bonded pair of substrates each having a wiring metal region. Each unit has four wiring metal regions on one substrate. A through electrode is connected to the end of each wiring metal region. A plain metal region is provided to surround two of the wiring metal regions. Between the two substrates, the wiring metal region is bonded to a corresponding wiring metal region on the other substrate, and the plain metal region is bonded to a corresponding plain metal region on the other substrate. In this model, the total area of ​​the through electrode, wiring metal region, and plain metal region is 60% of the total area.

[0192] In the model of Fig. 24(B), the wiring metal area is removed from the model of Fig. 24(C), leaving the through electrodes and plain metal area, and four through electrodes are connected to corresponding through electrodes of another substrate. In this model, the total area of ​​the through metal area and plain metal area is 30% of the total area.

[0193] In the model of Fig. 24(A), the through-hole regions are removed from the model of Fig. 24(B). In this model, the total area of ​​the through-hole metal regions is 3% of the total area.

[0194] In the model of Fig. 24(D), the gap between the wiring metal regions and the plain metal regions is smaller than that in the model of Fig. 24(C). This allows each wiring metal region to be surrounded by a plain metal region. In this model, the total area of ​​the through metal regions and the plain metal regions is 90% of the total area.

[0195] 24A to 24D, an electromagnetic wave parallel to the bonded surface was irradiated perpendicularly to the bonded surface as a noise source model. Fig. 25 shows the transmission characteristics of the parallel wave at frequencies from 0 GHz to 100 GHz.

[0196] When the total area of ​​the metal region was 3%, almost no effect in suppressing noise transmission was observed, whereas at 30%, 60%, and 90%, significant effects were observed across the entire frequency range from 0 GHz to 100 GHz. Furthermore, while 30% and 60% had roughly the same effect, 90% showed an even greater effect. From this, it can be said that a fairly high effect can be obtained when the metal region occupies 30% or more of the bonding surface. As a general interpretation, it can be assumed that a high effect can be obtained even with an occupation ratio of less than 30%. For example, it can be considered that a high effect can be obtained when the metal region occupies 20% or more of the bonding surface. Furthermore, an even higher effect can be obtained when the metal region occupies more than 60% of the bonding surface.

[0197] <Non-floating dummy pad> Hybrid bonding, in which substrates having a metal electrode and an insulating material on the same bonding surface are bonded together, is widely used in three-dimensional packaging. In order to bond hybrid substrates well, a good bonding surface must be prepared by CMP (chemical mechanical polishing). That is, the bonding surface is made up of a Cu pad as a fine electrode and an oxide, nitride, e.g., SiO as an insulating layer. ２These are made of materials with different polishing characteristics, such as low-k materials such as TEOS and SiCN. These must be subjected to CMP to a surface roughness Ra of within a few nanometers, and the Cu and insulating layer must either be flush with each other or the Cu must be recessed by a few nanometers relative to the insulating layer.

[0198] This is because, when the electrodes are formed in a convex shape, pressure is generally required during bonding, which causes distortion within the wafer and reduces the alignment accuracy of the bonding.To improve bonding accuracy, it is necessary to contact the substrates at the center using center push, generate a bonding wave from the center, and bond the entire bonding surface together without applying pressure (temporary bonding).

[0199] Natural bonding waves without pressure are a phenomenon in which two hydrophilized substrate surfaces, particularly non-metallic portions (insulating layer, semiconductor surface), bond together through van der Waals forces. Therefore, for example, it is necessary to wash the insulating layer with water after an activation process such as plasma treatment to make it hydrophilic. Furthermore, if the electrode pad is convex or spreads flat, the bonding wave of the insulating layer will not naturally spread across the entire bonding surface. Therefore, as mentioned above, it is also important that the electrode is not convex relative to the insulating layer surface, i.e., the electrode surface is either flush with the insulating layer surface or concave relative to the insulating layer surface.

[0200] Here, it is important to keep the recess of the electrode surface relative to the insulating layer surface within a few nanometers. After the hydrophilic insulating layer surface is temporarily bonded, the metal of the electrode expands upon heating. Part of the metal may diffuse. This electrically connects the opposing electrode surfaces. Therefore, the size of the recess on the electrode surface must be adjusted to a degree that allows connection between the electrodes by heating at a desired temperature. Although this depends on the heat resistance of the elements contained in the substrate, the heating conditions for the substrate are generally 350°C or less, preferably 200°C. At this temperature, the opposing electrode surfaces expand and come into contact, and in order to establish a good electrical connection, the recess of the electrode surface relative to the insulating layer surface must be a few nanometers or less.

[0201] The distribution of the microelectrode pads on the bonding surface also affects the quality of CMP. In the example shown in FIG. 26 , a substrate 4110 has a microelectrode 4111 and a metal solid area 4113 or an insulating layer solid area 4115 in the area other than the electrode. If the metal solid area 4113 or insulating layer solid area 4115 occupies a large area, the difference in polishing characteristics between the electrode area and the insulating layer area during CMP processing becomes greater. In many cases, insulating layers are harder than metal parts such as Cu. Therefore, the metal solid area 4113 will be significantly recessed, and conversely, the insulating layer 4115 will be significantly protruded (see FIG. 26 ).

[0202] One solution to this problem is to arrange metal dummy pads 4213 having a similar shape to the microelectrodes 4211 in areas of the substrate 4210 close to the microelectrodes 4211, with the same shape and periodicity as the microelectrodes, as shown in Fig. 27. However, unlike the microelectrodes 4211, conventional metal dummy pads 4213 are electrically floating. Some embodiments of the present disclosure also provide an aspect in which floating dummy pads are arranged on the bonding surface.

[0203] On the other hand, some embodiments of the present disclosure also provide a mode in which a non-floating dummy pad is arranged on the bonding surface. Through ingenuity, the inventors discovered that electrical characteristics can be further improved by electrically connecting the dummy pad to a power supply or ground rather than floating it. Floating dummy pads are ineffective in suppressing such electrical noise. In contrast, it has been found that electrically connecting the dummy pad to a power supply or ground is effective in suppressing noise. A wiring layer is arranged inside the substrate, for example, on the device surface. The dummy pad can be connected to a power supply line or a ground line through this wiring layer.

[0204] FIG. 28 shows a schematic cross section of a substrate 4310 according to one embodiment. A plurality of signal transmission metal pads (signal transmission pads) 4311 are arranged in an array on a bonding surface 4317 of the substrate 4310. The signal transmission pads 4311 are connected to signal transmission lines 4312. Furthermore, a plurality of dummy pads 4313 are arranged in an array similar to the signal transmission pads 4311 on other portions of the bonding surface 4317. The metal pads, including the plurality of signal transmission pads 4311 and the plurality of dummy pads 4313 (collectively referred to as metal pads), are arranged in an approximately uniform array across substantially the entire bonding surface. Furthermore, an insulating surface 4315 is arranged on the bonding surface 4317. Each of the plurality of first metal pads is surrounded by the insulating surface 4315. The dummy pads 4313 are connected to a power supply line or a ground line 4314. In other words, the dummy pads 4313 are not electrically floating.

[0205] The non-floating dummy pads and the electrode pads for signal transmission may be collectively referred to as metal pads. The metal pads may be periodically arranged across the bonding surface. In some embodiments, the total area of ​​the metal pads may be 30% or more of the area of ​​the bonding surface, allowing a large portion of the bonding surface to be occupied by the metal pads. In some embodiments, the total area of ​​the non-floating dummy pads may be larger than the total area of ​​the transmission signal pads, allowing a large portion of the bonding surface to be occupied by the non-floating metal regions. There may be more non-floating dummy pads than signal transmission pads. These aspects are effective solutions for noise reduction.

[0206] In some embodiments, the insulating layer surrounds each of the signal transmission pads and dummy pads individually. In some embodiments, the insulating layer is continuous across the entire bonding surface or across a large area on the bonding surface. In some embodiments, the signal transmission pads and dummy pads may have a uniform shape and periodicity. In some embodiments, the signal transmission pads and dummy pads may be arranged substantially uniformly in an array.

[0207] 29 shows an enlarged view (right) of a portion of the bonding surface 4417 of the wafer 4410 (left). Metal pads 4411, which collectively refer to electrode pads for signal transmission and dummy pads connected to a power supply or ground, are arranged in an array on the bonding surface 4417. Each metal pad 4411 is isolated and surrounded by an insulating layer 4415. This insulating layer 4415 is continuous across the bonding surface 4417.

[0208] Similar wafers (not shown) are prepared, and the bonding surfaces of the pair of wafers are brought into contact at their centers (center push). Almost no force is applied during this center push. This first brings the insulating layers of the bonding surface 4417 into contact with each other at the center of the wafer 4410, and then a natural bonding wave can propagate from there across the entire bonding surface (as indicated by the arrows in the figure). This allows for high-precision alignment or bonding, for example, within 1 μm.

[0209] The positioning of corresponding metal regions between substrates may be performed, for example, by providing a plurality of position adjustment marks on one substrate and a plurality of corresponding position adjustment marks at corresponding positions on the other substrate, and aligning both position adjustment marks with each other. The misalignment between both position adjustment marks may be measured by irradiating light transmitted through the substrates from either substrate side in a direction perpendicular to the joining surface, and observing an image of the position adjustment marks captured by the transmitted light using a camera provided on the opposite side.

[0210] As an example, the alignment between corresponding metal regions of the substrates is achieved by aligning alignment adjustment marks provided on both substrates with each other using light transmitted through the substrates. This allows for a positioning accuracy of, for example, ±1 μm. Furthermore, if the alignment is not sufficient, the substrates can be separated from each other immediately after temporary bonding, realigned, and then temporarily bonded again, and this process can be repeated until a predetermined positioning accuracy is achieved. This allows for a positioning accuracy of ±0.2 μm.

[0211] In some embodiments, the shape of the metal region or metal pad within the bonding surface may be a polygon, such as a rectangle or a square. The metal pad may be formed in a convex polygon. For example, the metal pad may be formed in a substantially square shape. For example, the metal pad may be formed in a substantially rectangular shape. For example, the metal pad may be a wiring metal region or wiring metal pad, and may be formed in a rectangular shape. The metal pad may be formed in a non-convex polygon. For example, the metal pad may be formed in an L-shape within the bonding surface, or may have a shape including multiple L-shaped bends.

[0212] In some embodiments, the shape of metal pads, such as signal transmission pads and dummy pads, at the bonding surface may be rounded. Angular shapes, such as square or rectangular corners, can cause interference with the propagation of the bonding wave. In some embodiments, the pads preferably have curved, rounded, circular, or elliptical shapes. The metal pads may be formed in the shape of a rounded polygon, i.e., substantially polygonal, with rounded or curved corners.

[0213] In some embodiments, a plurality of signal transmission metal pads and a plurality of dummy pads may be arranged in an array. In some embodiments, a portion where only a plurality of signal transmission metal pads are present and a portion where only a plurality of dummy pads are present may be formed on the bonding surface. For example, similar to the example shown in FIG. 7 , a plurality of signal transmission metal pads may be arranged in a portion of the bonding surface, such as the center, and a plurality of dummy pads may be arranged to surround them. In some embodiments, a portion where a plurality of signal transmission metal pads and a plurality of dummy pads are arranged together may exist on the bonding surface.

[0214] In some embodiments, the signal transmission metal pads and the dummy pads may be arranged in a similar array, i.e., the metal pads may be arranged with a certain regularity, with some of the metal pads being formed as the signal transmission metal pads and others being formed as the dummy pads.

[0215] In some embodiments, all of the dummy pads on one unit of bonding surface may be non-floating dummy pads. In some embodiments, the dummy pads may include non-floating dummy pads and floating dummy pads. Some of the dummy pads may be non-floating dummy pads and other dummy pads may be floating dummy pads.

[0216] In some embodiments, multiple signal-transmitting metal pads may be arranged in a portion, for example, the center, of the bonding surface, and multiple non-floating dummy pads may be arranged surrounding the signal-transmitting metal pads. For example, multiple signal-transmitting metal pads may be arranged in a portion, for example, the center, of the bonding surface, and multiple non-floating dummy pads and multiple floating dummy pads may be arranged surrounding the signal-transmitting metal pads. For example, multiple signal-transmitting metal pads may be arranged in a portion or the center of the bonding surface, and non-floating dummy pads may be arranged in a peripheral region (one circumference) of a predetermined width surrounding the signal-transmitting metal pads, and floating dummy pads may be arranged in other portions, for example, outside the peripheral region where the non-floating dummy pads are arranged. Alternatively, for example, a mixture of floating dummy pads and non-floating dummy pads may be arranged outside the peripheral region.

[0217] 7B illustrates an example of a mating surface 700B configuration including signal transmission pads 710B and dummy pads 720B, which may be used, for example, but not limited to, on either an interposer or a PCB, such as a single-ended pad surface.

[0218] The dummy pad 720B is not formed as a single, continuous, or solid pad, but is formed as a pad or pin. The dummy pad 720B includes a metal region for a power supply and a metal region for a ground. These metal regions are connected or configured to be connected to the power supply or the ground, respectively.

[0219] 7B, a signal transmission pad 710B is defined in a central portion 711B of the bonding surface 700B. The signal transmission pad 710B is not formed as a single, continuous, or solid pad, but is formed as an individual signal transmission pad 710B. The signal transmission pad 710B is connected or configured to be connected to the gate voltage (VDD) or ground (GND) of the device.

[0220] 7B , a bonding surface 700B is defined around a central portion 711B where signal transmission pads 710B are arranged, and a surrounding region 712B is defined around the central portion 711B. Dummy pads 720B are arranged in the surrounding region 712B. In some embodiments, all of the ground metal regions 720B in the surrounding region 712B may be connected to a power supply or ground. In other words, all of the ground metal regions 720B may be non-floating dummy pads.

[0221] Dummy pads 720B are arranged in an area further outside the surrounding area 712B. In some embodiments, all of these dummy pads 720B may be connected to a power supply or ground. In some embodiments, at least some of these dummy pads 720B may be connected to a power supply or ground, while others may be floating.

[0222] 7B shows two rows of dummy pads 720B arranged in the circumferential region 712B. However, the present disclosure is not limited to this. For example, one row of dummy pads 720B may be arranged in the circumferential region 712B. Alternatively, for example, three or more rows of dummy pads 720B may be arranged in the circumferential region 712B.

[0223] In Fig. 7B, the center portion 711B is defined in the center of the mating surface 700B. However, the center portion 711B does not have to be located at the geometric center of the mating surface 700B. For example, the center portion 711B may be located at a position offset in a certain direction of the mating surface 700B. In Fig. 7B, one center portion 711B is defined in the mating surface 700B. However, the mating surface 700B may have multiple center portions 711B.

[0224] However, it is not necessary to fill the entire bonding surface, i.e., the area other than the electrode pads on the bonding surface, with dummy pads. Furthermore, the pads on the entire bonding surface do not have to have the same shape, periodicity, or array pattern. For example, alignment marks, solid metal or insulator areas with a certain area, or other spaces may be arranged on the bonding surface to the extent that the influence on bonding wave propagation and alignment accuracy is not a problem.

[0225] A method for bonding substrates according to one embodiment will be described with reference to FIG. 30 . First, a pair of substrates (a first substrate 4510 and a second substrate 4520) to be bonded is prepared. The substrates 4510 and 4520 shown in FIG. 30 are configured similarly to those shown in FIG. 27 , for example. The signal transmission pads 4511 and 4521 and the dummy pads 4513 and 4523 are arranged in an array across the bonding surfaces 4517 and 4527 and are recessed from the insulating surfaces 4515 and 4525. This is an example; the metal pads 4511, 4513, 4521, and 4523 may be formed flush with the insulating surfaces 4515 and 4525. Alternatively, the metal pads 4511, 4513, 4521, and 4523 may be formed slightly higher or convex than the insulating surfaces 4515 and 4525, as long as they do not interfere with the natural bonding wave.

[0226] 30A, plasma treatment and hydrophilic treatment are performed on bonding surfaces 4517 and 4527. As a result, insulating surfaces 4515 and 4525 are made hydrophilic (hydrophilic insulating surfaces 4515H and 4525H in the drawing).

[0227] In another embodiment, the bonding surfaces 4517 and 4527 may be activated by irradiating them with a particle beam (such as an ion beam or a neutron beam) or plasma, thereby achieving a strong bond even if the metal pads are formed in a convex shape.

[0228] When the hydrophilized bonding surfaces 4517 and 4527 are brought into contact, the hydrophilized insulating surfaces 4515H and 4525H are bonded together as a whole by the propagation of the bonding wave, forming a temporary bonding surface 4550H (FIG. 30(B)). At this time, the signal transmission pads 4511 and 4521 and the dummy pads 4513 and 4523 are not electrically connected between the two substrates.

[0229] The bonded state is heated (annealed) to expand or deform the metal pads 4511, 4513, 4521, and 4523, thereby bonding the first signal transmission pad 4511 to the second signal transmission pad 4521 and the first dummy pad 4513 to the second dummy pad 4523. Electrical connections are established between the first signal transmission pad 4511 and the second signal transmission pad 4521 and between the first dummy pad 4513 and the second dummy pad 4523. As a result, the first substrate 4510 and the second substrate 4520 are bonded via a bonding interface 4550 ( FIG. 30(C) ).

[0230] In some embodiments, the total area of ​​the dummy pads may be greater than the total area of ​​the signal transmission pads. In some embodiments, the number of dummy pads may be greater than the number of signal transmission pads. This allows the entire bonding surface to be filled with metal pads, improving electrical properties such as noise suppression.

[0231] In some embodiments, the insulating surfaces 4515 and 4525 may not be bonded. A high bond strength can be achieved simply by bonding a large number of metal pads arranged on the bonding surfaces. However, in some embodiments, the insulating surfaces 4515 and 4525 may be bonded. This can further increase the bond strength.

[0232] 30, the dummy pads are connected to a power supply or ground, or are non-floating, on both the first substrate 4510 and the second substrate 4520. In some embodiments, one of the first substrate 4510 and the second substrate 4520 may have dummy pads connected to a power supply or ground (non-floating), while the other may have dummy pads that are not connected to a power supply or ground (floating).

[0233] In either case, the assembled body thus manufactured contains dummy pads (or non-floating dummy pads) connected to a power supply or ground, which can suppress the influence of noise generated inside one substrate of the assembled body on electronic elements on the other substrate.

[0234] Currently, various electronic devices such as PCs and smartphones use RF elements, clock generators, and various electronic elements operating in the GHz band. These high-frequency elements are illustrative and should not be interpreted as limiting. As used herein, the term "high-frequency element" generally refers to electronic elements or wiring operating in the bands ranging from 100 MHz to 100 GHz, particularly 1 GHz to 100 GHz. These high-frequency elements are also sources of noise. In three-dimensional mounting, these noise sources and susceptible elements or wiring are located in close proximity to each other, making noise a significant issue. Several embodiments of the present disclosure provide effective solutions to this problem.

[0235] The above-described embodiments or parts thereof can be combined with the embodiments, examples, or parts thereof of the present disclosure, unless there is a contradiction.

[0236] The present disclosure also provides the following embodiments: A001. A bonding structure, or the bonding structure described in any of the embodiments, comprising: a first substrate, the first substrate having a first bonding surface having a first signal carrying metal region and a first ground metal region insulated from the first signal carrying metal region; and a second substrate bonded to the first substrate, the second substrate having a second bonding surface having a second signal carrying metal region and a second ground metal region insulated from the second signal carrying metal region; wherein the first signal carrying metal region and the second signal carrying metal region are bonded, and the first ground metal region and the second ground metal region are bonded. A002. A bonding structure described in A001 or any of the embodiments, wherein the first substrate comprises a through electrode that penetrates the first substrate and is connected to the first signal carrying metal region, and / or the second substrate comprises a through electrode that penetrates the second substrate and is connected to the second signal carrying metal region. A003. A001. A junction structure as described in any of the embodiments, wherein the first substrate comprises a through electrode that penetrates the first substrate and is connected to the first ground metal region, and / or the second substrate comprises a through electrode that penetrates the second substrate and is connected to the second ground metal region. A004. A junction structure as described in any of the embodiments, wherein the first and / or second ground metal regions are connected to a ground or a power supply. A005. A junction structure as described in any of the embodiments, wherein the first signal-carrying metal surface and / or the first signal-carrying metal surface is connected to an electronic element (e.g., a transistor), and the ground or the power supply is the ground or the power supply of the electronic element (e.g., a transistor). A011. A001, or any of the embodiments, wherein the combined area of ​​the first signal carrying metal region and the first ground metal region is 10% or more of the area of ​​the first bonding surface, and / or the combined area of ​​the second signal carrying metal region and the second ground metal region is 10% or more of the area of ​​the second bonding surface.A012. The joining structure described in A001 or any of the embodiments, wherein the total area of ​​the first signal carrying metal region and the first ground metal region is 30% or more of the area of ​​the first joining surface, and / or the total area of ​​the second signal carrying metal region and the second ground metal region is 30% or more of the area of ​​the second joining surface. A013. The joining structure described in A001 or any of the embodiments, wherein the total area of ​​the first signal carrying metal region and the first ground metal region is 60% or more of the area of ​​the first joining surface, and / or the total area of ​​the second signal carrying metal region and the second ground metal region is 60% or more of the area of ​​the second joining surface. A014. The joining structure described in A001 or any of the embodiments, wherein the area of ​​the first or second ground metal region is larger than the area of ​​the first or second signal carrying metal region. A021. A001 or any of the embodiments, wherein the first or second signal carrying metal region is substantially surrounded by the first or second ground metal region within the first or second bonding surface. A031. A001 or any of the embodiments, wherein the first or second signal carrying metal region is disposed spaced apart from the first or second ground metal region within the first or second bonding surface. A033. A001 or any of the embodiments, wherein the first or second signal carrying metal region is disposed spaced apart from the first or second ground metal region by 0.1 μm or more within the first or second bonding surface. A034. A001 or any of the embodiments, wherein the first or second bonding surface comprises an insulating surface at a spaced apart portion between the first or second signal carrying metal region and the first or second ground metal region.A035. A joining structure as described in A001 or any of the embodiments, wherein the first joining surface comprises a first insulating surface disposed between the first signal carrying metal region and the first ground metal region, the second joining surface comprises a second insulating surface disposed between the second signal carrying metal region and the second ground metal region, and the first insulating surface and the second insulating surface are joined to each other. A035b. A joining structure as described in A001 or any of the embodiments, wherein the first joining surface comprises a first insulating surface disposed between the first signal carrying metal region and the first ground metal region, the second joining surface comprises a second insulating surface disposed between the second signal carrying metal region and the second ground metal region, and the first insulating surface and the second insulating surface are not joined to each other. A036. A joining structure as described in A001 or any of the embodiments, wherein the first or second signal carrying metal region and the first or second ground metal region are not in contact with each other. A037. A001 or any of the embodiments, wherein the separation between the first or second signal carrying metal region and the first or second ground metal region is formed by gas or a substantial vacuum. A041. A001 or any of the embodiments, wherein the first and / or second signal carrying metal region comprises a plurality of first and / or second signal carrying metal regions. A042. A001 or any of the embodiments, wherein the plurality of first and / or second signal carrying metal regions comprises at least one signal carrying metal region for carrying an analog signal and at least one signal carrying metal region for carrying a digital signal. A051. A001 or any of the embodiments, wherein the first and / or second ground metal region comprises a plurality of first and / or second ground metal regions insulated from each other within the corresponding joint plane. A052. A001, or any embodiment, wherein the plurality of first and / or second ground metal regions are connected to ground and / or different power sources.A053. A joining structure as described in A001 or any of the embodiments, wherein some of the plurality of first and / or second ground metal regions are arranged to surround the signal transmission metal region for analog signals within the corresponding joining surface, and other parts of the plurality of first and / or second ground metal regions are arranged to surround the signal transmission metal region for digital signals within the corresponding joining surface. A061. A joining structure as described in A001 or any of the embodiments, wherein the ground metal region has a metal material arranged over the entire region or over the entire region. A062. A joining structure as described in A001 or any of the embodiments, wherein the ground metal region has a metal material arranged to cover a portion of the region in terms of area. A063. A joining structure as described in A001 or any of the embodiments, wherein the ground metal region has a metal material unoccupied portion where no metal material is arranged. A064. A065. A joint structure according to A001 or any of the embodiments, wherein the non-metallic material portions are periodically arranged over the entire or a portion of the ground metal region. A066. A joint structure according to A001 or any of the embodiments, wherein the non-metallic material portions or the metallic material are periodically arranged within the ground metal region. A067. A joint structure according to A001 or any of the embodiments, wherein the non-metallic material portions or the metallic material are arranged in a mesh pattern within the ground metal region. A068. A joint structure according to A001 or any of the embodiments, wherein the area of ​​the non-metallic material portions is 10% to 50% of the area of ​​the ground metal region.A101. a second substrate bonded to the first substrate, the second substrate having a first bonding surface including a first signal carrying metal region and a first ground metal region insulated from the first signal carrying metal region; a second substrate bonded to the first substrate, the second substrate having a second upper signal carrying metal region and a second upper ground metal region insulated from the second upper signal carrying metal region, the second upper bonding surface facing the first bonding surface; and a second lower bonding surface including a second lower signal carrying metal region and a second lower ground metal region insulated from the second lower signal carrying metal region; and a third substrate bonded to the second substrate, the third substrate having a third signal carrying metal region and a third ground metal region insulated from the third signal carrying metal region, the third bonding surface facing the second lower bonding surface; A joint structure, wherein the second lower ground metal region and the third ground metal region are joined. A102. The joint structure according to A101 or any of the embodiments, comprising a plurality of substrates joined to each other. A201. An electronic element comprising the joint structure according to A101 or any of the embodiments. A202. An electronic circuit module comprising the joint structure according to A101 or any of the embodiments. A203. An electronic device comprising the joint structure according to A101 or any of the embodiments.B001. A method of bonding substrates, or the method of any embodiment, comprising: providing a first substrate having a first bonding surface with a first signal carrying metal region and a first ground metal region insulated from the first signal carrying metal region; providing a second substrate bonded to the first substrate, the second bonding surface having a second signal carrying metal region and a second ground metal region insulated from the second signal carrying metal region; contacting the first signal carrying metal region with the second signal carrying metal region; and contacting the first ground metal region with the second ground metal region. B011. The method of B001, or any embodiment, wherein contacting the first signal carrying metal region with the second signal carrying metal region comprises electrically connecting the first signal carrying metal region with the second signal carrying metal region, and contacting the first ground metal region with the second ground metal region. B012. B001. The method of any of the embodiments, further comprising: prior to contacting the first signal carrying metal region with the second signal carrying metal region and contacting the first ground metal region with the second ground metal region, activating a surface of at least one of the first signal carrying metal region and the second signal carrying metal region, and activating a surface of at least one of the first ground metal region and the second ground metal region, wherein contacting the first signal carrying metal region and the second signal carrying metal region comprises contacting the activated surface with the other, and contacting the first ground metal region with the second ground metal region comprises contacting the activated surface with the other. B013. The method of any of the embodiments, further comprising: prior to contacting the first signal carrying metal region with the second signal carrying metal region and contacting the first ground metal region with the second ground metal region, activating a surface of at least one of the first signal carrying metal region and the second signal carrying metal region, and activating a surface of at least one of the first ground metal region and the second ground metal region, wherein contacting the first signal carrying metal region with the second signal carrying metal region comprises contacting the activated surface with the other, and contacting the first ground metal region with the second ground metal region comprises contacting the activated surface with the other. B014. The method of any of the embodiments, further comprising: prior to contacting the first signal carrying metal region with the second signal carrying metal region and contacting the first ground metal region with the second ground metal region, activating a surface of at least one of the first signal carrying metal region and the second signal carrying metal region, and activating a surface of at least one of the first ground metal region and the second ground metal region, wherein contacting the first signal carrying metal region with the second signal carrying metal region comprises contacting the activated surface with the other. B015. The method of any of the embodiments, further comprising: prior to contacting the first signal carrying metal region with the second signal carrying metal region and contacting the first ground metal region with the second ground metal region,B014. The method of B012, or any of the embodiments, wherein the activation comprises a process selected from the group consisting of plasma treatment, ion bombardment, atomic beam irradiation, and radical irradiation. B013. The method of B001, or any of the embodiments, wherein the contacting comprises contacting in a vacuum. B016. The method of B001, or any of the embodiments, wherein the contacting of the first signal carrying metal region with the second signal carrying metal region and the contacting of the first ground metal region with the second ground metal region are performed without heating or at room temperature. B017. The method of B001, or any of the embodiments, further comprising: contacting the first signal carrying metal region with the second signal carrying metal region; and heating the first substrate and the second substrate after contacting the first ground metal region with the second ground metal region.

[0237] C001. A bonded structure or the bonded structure of any of the embodiments, comprising: a first substrate having a first bonding surface having a first signal carrying metal region and a first ground metal region; and a second substrate bonded to the first substrate, having a second bonding surface having a second signal carrying metal region and a second ground metal region; wherein the first signal carrying metal region and the second signal carrying metal region are bonded, and the first ground metal region and the second ground metal region are bonded, and a total area of ​​the first signal carrying metal region and the ground metal region is 30% or more of an area of ​​the first bonding surface, and / or a total area of ​​the second signal carrying metal region and the ground metal region is 30% or more of an area of ​​the second bonding surface. C002. C001, or any of the embodiments, wherein a combined area of ​​the first signal carrying metal region and the ground metal region is greater than 60% of an area of ​​the first bonding surface, and / or a combined area of ​​the second signal carrying metal region and the ground metal region is greater than 60% of an area of ​​the second bonding surface.

[0238] E001. A bonded structure, or the bonded structure described in any of the embodiments, comprising: a first substrate, the first substrate having a first bonding surface having a plurality of first signal carrying metal regions and a first plane metal region formed to surround the plurality of first signal carrying metal regions; and a second substrate bonded to the first substrate, the second substrate having a second bonding surface having a plurality of second signal carrying metal regions and a second plane metal region formed to surround the plurality of second signal carrying metal regions; wherein the plurality of first signal carrying metal regions are bonded to the plurality of second signal carrying metal regions, and the first plane metal region is bonded to the second plane metal region. E011. A bonded structure described in E001 or any of the embodiments, wherein a distance between at least one first signal carrying metal region of the plurality of first signal carrying metal regions and the first plane metal region is 1 μm or less, and a distance between at least one second signal carrying metal region of the plurality of second signal carrying metal regions and the second plane metal region is 1 μm or less. E012. E011. The bonding structure according to E011 or any of the embodiments, wherein the distance is 0.5 μm or less. E013. The bonding structure according to E011 or E012, or any of the embodiments, wherein the distance is 0.25 μm or less. E021. The bonding structure according to any one of E001 to E013, or any of the embodiments, wherein one or both of the first substrate and the second substrate have a plain metal region inside the substrate (buried).

[0239] F001. A bonding structure, or a bonding structure described in any of the embodiments, comprising: a first substrate, the first substrate having a first bonding surface having a first wiring metal region; and a second substrate bonded to the first substrate, the second substrate having a second bonding surface having a second wiring metal region; wherein the first wiring metal region and the second wiring metal region are bonded. F011. A bonding structure described in F001 or any of the embodiments, wherein the first bonding surface further has a first plane metal region formed to surround the first wiring metal region, and the second bonding surface further has a second plane metal region formed to surround the second wiring metal region, wherein the first plane metal region and the second plane metal region are bonded. F021. A bonding structure described in F001 or F011, or any of the embodiments, wherein one or both of the first and second substrates have a plane metal region embedded within the substrate.

[0240] G001. A bonding structure or a bonding structure according to any one of the embodiments, comprising: a first substrate having a first bonding surface including a first differential signal plus metal region, a first differential signal minus metal region, and a first plane metal region formed to surround the first differential signal plus metal region and the first differential signal minus metal region; and a second substrate having a second bonding surface including a second differential signal plus metal region, a second differential signal minus metal region, and a second plane metal region formed to surround the second differential signal plus metal region and the second differential signal minus metal region, wherein the first differential signal plus metal region and the second differential signal plus metal region are bonded, the first differential signal minus metal region and the second differential signal minus metal region are bonded, and the first plane metal region and the second plane metal region are bonded. G001b. 1. A bonding structure comprising: a first substrate having a first bonding surface including a pair of first differential signal plus metal regions and first differential signal minus metal regions; and a first plane metal region formed to surround the pair of first differential signal plus metal regions and the first differential signal minus metal regions; and a second substrate having a second bonding surface including a pair of second differential signal plus metal regions and second differential signal minus metal regions; and a second plane metal region formed to surround the pair of second differential signal plus metal regions and the second differential signal minus metal regions, wherein the first differential signal plus metal region and the second differential signal plus metal region are bonded, the first differential signal minus metal region and the second differential signal minus metal region are bonded, and the first plane metal region and the second plane metal region are bonded. G011. The bonding structure of G001 or any embodiment, wherein one or both of the first and second substrates have a plane metal region embedded within the substrate.G021. The junction structure of G001 or any of the embodiments, wherein the first plane metal region is formed to surround the first differential signal plus metal region, the first differential signal minus metal region, and one or both of a first single-ended metal region and a first power metal region, and the second plane metal region is formed to surround the second differential signal plus metal region, the second differential signal minus metal region, and one or both of a second single-ended metal region and a second power metal region, and the first single-ended metal region and the second single-ended metal region are joined together, and / or the first power metal region and the second power metal region are joined together. G021b. G001b or any of the embodiments, wherein the first plane metal region is further formed to surround one or both of a first single-ended metal region and a first power metal region, and the second plane metal region is further formed to surround one or both of a second single-ended metal region and a second power metal region, and the first single-ended metal region and the second single-ended metal region are bonded together, and / or the first power metal region and the second power metal region are bonded together.

[0241] H001. A joint structure having a plurality of stacked substrates, or the joint structure described in any of the embodiments, wherein one of the plurality of stacked substrates has a high-frequency element, and one or more, or any metal region of the plurality of stacked substrates has a metal region configured to suppress transmission of electromagnetic noise emitted from the high-frequency element in the stacking direction. H001b. The joint structure described in H001 or any of the embodiments, wherein the metal region is configured to suppress transmission of electromagnetic noise in a direction perpendicular to the first and second joining surfaces. H011. The joint structure described in H001 or any of the embodiments, wherein the high-frequency element operates at 1 GHz or higher. H021. The joint structure described in H001 or any of the embodiments, wherein the metal region has an area of ​​30% or more of the area occupied by the high-frequency element when viewing the joint structure in the stacking direction of the substrates. H031. The joint structure described in H001 or any of the embodiments, wherein the metal region includes a plain metal region. H032. A joining structure according to H031 or any of the embodiments, wherein the plurality of stacked substrates include a first substrate and a second substrate that are joined together, wherein the joining surface of the first substrate has a first plain metal region, and the joining surface of the second substrate has a second plain metal region, and the first plain metal region and the second plain metal region are joined together. H033. A joining structure according to H031 or H032, or any of the embodiments, wherein the metal region includes a plain metal region formed inside the plurality of stacked substrates. H041. A joining structure according to H001 or any of the embodiments, wherein the metal region configured to suppress transmission of electromagnetic noise in the stacking direction is a ground metal region.

[0242] I001. A bonding structure, or the bonding structure of any of the embodiments, comprising: i) a first substrate having a first bonding surface, the first bonding surface comprising: a plurality of first signal transmission pads arranged in an array; a plurality of first dummy pads arranged in a similar array on a portion of the first bonding surface other than the portion where the plurality of first signal pads are arranged; and a first insulating surface; wherein a plurality of first metal pads including the plurality of first signal transmission pads and the plurality of first dummy pads are arranged in an array substantially uniformly across substantially the entire first bonding surface, and each of the plurality of first metal pads is surrounded by a first insulating surface; and ii) a second substrate bonded to the first substrate, the second bonding surface comprising: a plurality of second signal transmission pads arranged in an array; a plurality of second dummy pads arranged in a similar array on a portion of the second bonding surface other than the portion where the plurality of second signal pads are arranged; and a second insulating surface; a second substrate, wherein a plurality of second metal pads, including the plurality of second signal transmission pads and a plurality of first dummy pads, are arranged substantially uniformly in an array over substantially the entire second bonding surface, and each of the plurality of second metal pads is surrounded by a second insulating surface; wherein each of the plurality of first signal transmission metal pads is bonded to each of the plurality of second signal transmission metal pads, and each of the plurality of first dummy pads is bonded to each of the plurality of second dummy pads. I002. A bonding structure as described in I001 or any of the embodiments, wherein the plurality of first dummy pads are connected to a power supply or ground, and the plurality of second dummy pads are connected to a power supply or ground. I003. A bonding structure as described in I001 or any of the embodiments, wherein one or at least one of the plurality of first dummy pads and the plurality of second dummy pads is connected to a power supply or ground. I004. 1001 or any of the embodiments, wherein at least some of the plurality of first dummy pads and the plurality of second dummy pads are connected to a power supply or a ground.I005. The bonding structure described in I001 or any of the embodiments, wherein some of the plurality of first dummy pads and the plurality of second dummy pads are connected to a power supply or ground, and other some of the plurality of first dummy pads and the plurality of second dummy pads are floating. I006. The bonding structure described in I001 or any of the embodiments, wherein at least some of the bonded first and second dummy pads are arranged in a circumferential region of the plurality of first and second signal transmission pads, and the plurality of first dummy pads arranged in the circumferential region are connected to a power supply or ground. I011. The bonding structure described in I001 or any of the embodiments, wherein the first insulating surface and the second insulating surface are bonded. I011b. The bonding structure described in I001 or any of the embodiments, wherein the first insulating surface and the second insulating surface are not bonded. I012. I001 or any of the embodiments, wherein the first insulating surface is formed substantially continuously across the first bonding surface, and the second insulating surface is formed substantially continuously across the second bonding surface. I013. I001 or any of the embodiments, wherein the plurality of first metal pads and the plurality of second metal pads have rounded shapes (shapes with in-plane contours having substantially no corners). I014. I001 or any of the embodiments, wherein the total area of ​​the plurality of first dummy pads is larger than the total area of ​​the first signal transmission pad, and the total area of ​​the plurality of second dummy pads is larger than the total area of ​​the second signal transmission pad. I015. I001 or any of the embodiments, wherein the total area of ​​the plurality of first metal pads is 30% or more of the area of ​​the first bonding surface, and the total area of ​​the plurality of second metal pads is 30% or more of the area of ​​the second bonding surface. I016. 1001 or any of the embodiments, wherein the alignment accuracy between the plurality of first metal pads and the plurality of second metal pads is within 1 μm.I017. The joining structure described in I001 or any of the embodiments, wherein the plurality of first signal transmission pads include a first differential signal plus metal region and a first differential signal minus metal region, and / or the plurality of second signal transmission pads include a second differential signal plus metal region and a second differential signal minus metal region. I018. The joining structure described in I001 or any of the embodiments, wherein at least a portion of the plurality of first metal pads and the plurality of second metal pads have metal regions configured to suppress transmission of electromagnetic noise in a direction perpendicular to the first and second joining surfaces. I021. The joining structure described in I001 or any of the embodiments, wherein at least one of the first substrate and the second substrate includes a high-frequency element or an element operating at a frequency of 1 GHz or higher. I031. I001, or any of the embodiments, wherein the plurality of first dummy pads are arranged to surround the plurality of first signal transmission pads, and / or the plurality of second dummy pads are arranged to surround the plurality of second signal transmission pads.I101. a first insulating surface; b) a second substrate having a second bonding surface; c) a second bonding surface having a second bonding surface; d) a second insulating surface; a method comprising: bonding each of the plurality of first signal-carrying metal pads to each of the plurality of second signal-carrying metal pads; and bonding each of the plurality of first dummy pads to each of the plurality of second dummy pads. I102. The method of I101 or any embodiment, wherein the plurality of first dummy pads are connected to a power supply or ground or are non-floating, and the plurality of second dummy pads are connected to a power supply or ground or are non-floating. I103. The method of I101 or any embodiment, wherein one or at least one of the plurality of first dummy pads and the plurality of second dummy pads is connected to a power supply or ground. I104. The method of I101 or any embodiment, wherein at least some of the plurality of first dummy pads and the plurality of second dummy pads are connected to a power supply or ground.I105. The method according to I101 or any of the embodiments, wherein some of the first dummy pads and some of the second dummy pads are connected to a power supply or ground, and other parts of the first dummy pads and some of the second dummy pads are floating. I106. The method according to I101 or any of the embodiments, wherein at least some of the first dummy pads are arranged in a first surrounding region of the first signal transmission pads, and at least some of the second dummy pads are arranged in a second surrounding region of the second signal transmission pads, the first signal transmission pads in the first peripheral region and the second signal transmission pads in the second peripheral region are joined together, and at least one or both of the first dummy pads in the first surrounding region and the second signal transmission pads in the second peripheral region are connected to a power supply or ground. I111. I101. The method of any of the embodiments, wherein the plurality of first signal carrying metal pads and the plurality of first dummy pads on the first bonding surface are formed convexly with respect to the first insulating surface, and / or the plurality of second signal carrying metal pads and the plurality of second dummy pads on the second bonding surface are formed convexly with respect to the second insulating surface. I112. The method of I101. or any of the embodiments, further comprising bonding the first insulating surface and the second insulating surface. I115. The method of I101. or any of the embodiments, wherein the first insulating surface is formed substantially continuously across the first bonding surface, and the second insulating surface is formed substantially continuously across the second bonding surface. I121. The method according to any one of I101 and I112, wherein the first insulating surface, the plurality of first signal-transmitting metal pads, and the plurality of first dummy pads on the first bonding surface are formed to be substantially flush with each other, and the second insulating surface, the plurality of second signal-transmitting metal pads, and the plurality of second dummy pads on the second bonding surface are formed to be substantially flush with each other.I122. The method of I101 or any embodiment, wherein the plurality of first signal-carrying metal pads and the plurality of first dummy pads on the first bonding surface are recessed relative to the first insulating surface, and / or the plurality of second signal-carrying metal pads and the plurality of second dummy pads on the second bonding surface are recessed relative to the second insulating surface. I123. The method of I101 or any embodiment, further comprising activating a surface of at least one or both of the plurality of first metal pads and the plurality of first metal pads prior to bonding in step c). I124. The method of I123 or any embodiment, wherein the activation comprises a process selected from the group consisting of plasma treatment, ion bombardment, atomic beam irradiation, and radical irradiation. I124b. The method of I124 or any embodiment, wherein the background is a vacuum. I125. The method according to I123, I124, or any of the embodiments, wherein the bonding in c) includes, after the activation, contacting the first bonding surface and the second bonding surface in a vacuum, and electrically connecting the plurality of first metal pads to the plurality of first metal pads without heating or at room temperature. I126. The method according to I124, or any of the embodiments, wherein the surfaces of the plurality of first metal pads and the plurality of first metal pads are bonded to a background of 1 x 10. －５I127. The method according to I126 or any embodiment, further comprising irradiating a particle beam in a vacuum of 1 Pa (Pascal) or less to activate the plurality of first metal pads whose surfaces have been activated, and step c) includes directly bonding the plurality of first metal pads with the plurality of first metal pads after the activation. I127. The method according to I126 or any embodiment, further comprising annealing the bonded first substrate and the second substrate at a temperature of 200 degrees Celsius or less without pressure after step c). I128. The method according to I127 or any embodiment, wherein the first insulating surface and the second insulating surface are not bonded. I131. The method according to I101 or any embodiment, wherein the first insulating surface, the plurality of first signal carrying metal pads, and the plurality of first dummy pads on the first bonding surface are formed substantially flush with each other, and the second insulating surface, the plurality of second signal carrying metal pads, and the plurality of second dummy pads on the second bonding surface are formed substantially flush with each other. I132. I131. The method according to any one of the embodiments, further comprising: before step c), performing a surface activation treatment on at least one of the first bonding surface and the second bonding surface; and after the surface activation treatment, performing a hydrophilization treatment on at least one of the first bonding surface and the second bonding surface. I133. The method according to step I132. Or any one of the embodiments, wherein step c) comprises bonding the hydrophilically treated first bonding surface and the second bonding surface in a vacuum. I134. The method according to step I133. Or any one of the embodiments, further comprising annealing the bonded first substrate and the second substrate without pressure at a temperature of 200 degrees Celsius or less, or optionally 150 degrees Celsius or less. I141. The method according to step I001. Or any one of the embodiments, wherein during bonding, the alignment accuracy between the plurality of first metal pads and the plurality of second metal pads is within 1 μm.I201. A substrate having a bonding surface for use in hybrid bonding, or the substrate of any of the embodiments, wherein the bonding surface comprises: a plurality of signal transmission pads arranged in an array; a plurality of dummy pads arranged in a similar array on a remainder of the first bonding surface; and an insulating surface, wherein a plurality of metal pads, including the plurality of signal transmission pads and the plurality of dummy pads, are arranged in a generally uniform array across substantially the entire bonding surface, each of the plurality of metal pads being surrounded by an insulating surface, and at least a portion of the plurality of dummy pads are connected to a power source or ground.

[0243] J001. In any embodiment, the metal region, metal pad, or pin comprises copper (Cu).

[0244] Terms or expressions used in this specification that express positional relationships, such as "upper substrate," "middle substrate," "lower substrate," "second layer from the top," "upper surface," "lower surface," "upper side," and "lower side," should not necessarily be construed as being defined relative to the vertical direction, the direction of gravity, or a particular direction of the device, but are used illustratively or for convenience in explaining the drawings. For example, the "upper substrate," "middle substrate," and "lower substrate" may be expressed as the "first substrate," "second substrate," and "third substrate," respectively (in any order), and the "upper surface" and "lower surface" may be expressed as the "first substrate" and "second substrate," respectively (in any order), or may be expressed using any number, adjective, other noun, or combination thereof, as appropriate.

[0245] The present disclosure does not exclude inventions in which part or all of the technical matters relating to a certain subject matter described in this specification are applied to technical matters of other subjects, but also provides such inventions. Even if the subject matter of the description in this specification is a joint structure, the content should not be interpreted as being limited, and may also be applied to other subjects, such as methods.

[0246] Several embodiments and examples of the present disclosure have been described above, but these embodiments and examples exemplify the present disclosure. For example, the above embodiments have been described in detail to clearly explain the present disclosure, and additional changes in dimensions, configurations, materials, and circuits may be made as necessary. Note that embodiments that combine any one or more features of the present disclosure described above are also included within the scope of the present disclosure. The claims encompass numerous modifications to the embodiments without departing from the technical spirit of the present disclosure. Therefore, the embodiments and examples disclosed herein are provided for illustrative purposes and should not be considered to limit the scope of the present disclosure.

Claims

1. A bonding structure comprising: i) a first substrate having a first bonding surface, the first bonding surface comprising: a plurality of first signal transmission pads arranged in an array; a plurality of first dummy pads arranged in a similar array on a portion of the first bonding surface other than the portion on which the plurality of first signal transmission pads are arranged; and a first insulating surface; a plurality of first metal pads including the plurality of first signal transmission pads and the plurality of first dummy pads are arranged in an array substantially uniformly over substantially the entire first bonding surface, and each of the plurality of first metal pads is surrounded by a first insulating surface; and ii) a second substrate bonded to the first substrate, the second bonding surface comprising: a plurality of second signal transmission pads arranged in an array; a plurality of second dummy pads arranged in a similar array on a portion of the second bonding surface other than the portion on which the plurality of second signal pads are arranged; and a second insulating surface; a second substrate, wherein a plurality of second metal pads including the plurality of second signal transmission pads and the plurality of second dummy pads are arranged substantially uniformly in an array across substantially the entire second bonding surface, and each of the plurality of second metal pads is surrounded by a second insulating surface; wherein each of the plurality of first signal transmission metal pads is bonded to each of the plurality of second signal transmission metal pads, and each of the plurality of first dummy pads is bonded to each of the plurality of second dummy pads, at least a portion of the bonded first and second dummy pads are arranged in a circumferential region of the plurality of first and second signal transmission pads, and the plurality of first dummy pads arranged in the circumferential region are connected to a power supply or ground.

2. The joining structure according to claim 1, wherein the first metal pads and the second metal pads have a rounded shape.

3. A junction structure according to claim 1, wherein the plurality of first metal pads comprises a first wiring metal region, and / or the plurality of second metal pads comprises a second wiring metal region.

4. A junction structure as claimed in claim 1, wherein the plurality of first signal transmission pads include a first differential signal plus metal region and a first differential signal minus metal region, and / or the plurality of second signal transmission pads include a second differential signal plus metal region and a second differential signal minus metal region.

5. A joining structure as claimed in claim 1, wherein at least a portion of the plurality of first metal pads and the plurality of second metal pads have metal regions configured to suppress the transmission of electromagnetic noise in a direction perpendicular to the first and second joining surfaces.

6. A joint structure according to claim 1, wherein the first insulating surface and the second insulating surface are joined together.

7. A joint structure according to claim 1, wherein the first insulating surface and the second insulating surface are not joined.

8. A bonding structure according to any one of claims 1 to 7, wherein the first metal pads and the second metal pads comprise copper.

9. A joint structure according to any one of claims 1 to 8, comprising a plurality of substrates joined together.

10. An electronic element, an electronic circuit module, or an electronic device comprising the junction structure according to any one of claims 1 to 8.

11. A method for bonding substrates, comprising: a) providing a first substrate having a first bonding surface, the first bonding surface having: a plurality of first signal transmission pads arranged in an array; a plurality of first dummy pads arranged in a similar array on a portion of the first bonding surface other than the portion on which the plurality of first signal pads are arranged; and a first insulating surface, the plurality of first metal pads including the plurality of first signal transmission pads and the plurality of first dummy pads are arranged in an array substantially uniformly over substantially the entire first bonding surface, and each of the plurality of first metal pads is surrounded by the first insulating surface; b) providing a second substrate having a second bonding surface, the second bonding surface having: a plurality of second signal transmission pads arranged in an array; a plurality of second dummy pads arranged in a similar array on a portion of the second bonding surface other than the portion on which the plurality of second signal pads are arranged; and a second insulating surface, the plurality of second metal pads including the plurality of second signal transmission pads and the plurality of first dummy pads are arranged in an array substantially uniformly over substantially the entire second bonding surface, and each of the plurality of second metal pads is surrounded by the second insulating surface; c) bonding each of the plurality of first signal transmitting metal pads to each of the plurality of second signal transmitting metal pads; and bonding each of the plurality of first dummy pads to each of the plurality of second dummy pads, wherein at least a portion of the plurality of first dummy pads are arranged in a first surrounding region of the plurality of first signal transmitting pads, and at least a portion of the plurality of second dummy pads are arranged in a second surrounding region of the plurality of second signal transmitting pads, the plurality of first signal transmitting pads in the first peripheral region and the plurality of second signal transmitting pads in the second peripheral region are bonded to each other, and at least one of the plurality of first dummy pads in the first surrounding region and the plurality of second signal transmitting pads in the second peripheral region is connected to a power supply or a ground.

12. The method of claim 11, further comprising, prior to step c), activating a surface of said plurality of first metal pads and a surface of said plurality of first metal pads.

13. The method of claim 12, wherein said activating comprises subjecting a surface of said plurality of first metal pads and a surface of said plurality of first metal pads to a process selected from the group consisting of plasma treatment, ion bombardment, atomic beam irradiation, and radical irradiation at a background pressure of vacuum.

14. The method of claim 13, further comprising: forming a surface of the plurality of first metal pads and the plurality of first metal pads on a 1×10 －５ The method further comprises irradiating the first metal pads with a particle beam in a vacuum of Pa (Pascal) or less to activate the first metal pads, and the step c) includes directly bonding the first metal pads with the activated surfaces to the first metal pads after the activation.

15. The method of claim 14, further comprising, after step c), annealing the bonded first and second substrates at a temperature of 200 degrees Celsius or less without pressure.

16. The method of claim 15, wherein the first insulating surface and the second insulating surface are not bonded.

17. A method according to claim 11, wherein the first insulating surface, the plurality of first signal transmitting metal pads and the plurality of first dummy pads on the first bonding surface are formed to be substantially flush with each other, and the second insulating surface, the plurality of second signal transmitting metal pads and the plurality of second dummy pads on the second bonding surface are formed to be substantially flush with each other.

18. The method according to claim 17, further comprising: prior to step c), performing a surface activation treatment on at least one of the first bonding surface and the second bonding surface; and after the surface activation treatment, performing a hydrophilization treatment on at least one of the first bonding surface and the second bonding surface.

19. The method according to claim 18, wherein the step c) includes bonding the first bonding surface and the second bonding surface that have been hydrophilically treated in a vacuum.

20. The method of claim 19, further comprising annealing the bonded first and second substrates at a temperature of 200 degrees Celsius or less without pressure.

21. The method of any of claims 11 to 20, wherein the first plurality of metal pads and the second plurality of metal pads comprise copper.

22. A bonding structure comprising: i) a first substrate having a first bonding surface, the first bonding surface having: a plurality of first signal transmission pads arranged in an array; a plurality of first dummy pads arranged in a similar array on a portion of the first bonding surface where the plurality of first signal pads are arranged; and a first insulating surface; a plurality of first metal pads including the plurality of first signal transmission pads and the plurality of first dummy pads are arranged in an array substantially uniformly over substantially the entire first bonding surface, and each of the plurality of first metal pads is surrounded by a first insulating surface; and ii) a second substrate having a second bonding surface bonded to the first substrate, the second bonding surface having: a plurality of second signal transmission pads arranged in an array; a plurality of second dummy pads arranged in a similar array on a portion of the second bonding surface other than the portion of the second bonding surface where the plurality of second signal pads are arranged; and a second insulating surface; a plurality of second metal pads including the plurality of second signal transmission pads and the plurality of second dummy pads are arranged in an array substantially uniformly over substantially the entire second bonding surface, and each of the plurality of second metal pads is surrounded by a second insulating surface; a second substrate; each of the plurality of first signal transmitting metal pads and each of the plurality of second signal transmitting metal pads are bonded to each of the plurality of first dummy pads and each of the plurality of second dummy pads are bonded to each of the plurality of first metal pads and each of the plurality of second metal pads have a rounded shape.

23. A bonding structure comprising: i) a first substrate having a first bonding surface, the first bonding surface having: a pair of a first differential signal plus metal region and a first differential signal minus metal region; and a first plane metal region formed to surround the pair of the first differential signal plus metal region and the first differential signal minus metal region; and ii) a second substrate having a second bonding surface, the second bonding surface having: a pair of a second differential signal plus metal region and a second differential signal minus metal region; and a second plane metal region formed to surround the pair of the second differential signal plus metal region and the second differential signal minus metal region, wherein the first differential signal plus metal region and the second differential signal plus metal region are bonded, the first differential signal minus metal region and the second differential signal minus metal region are bonded, and the first plane metal region and the second plane metal region are bonded.

24. A junction structure as described in claim 23, wherein the first plane metal region is further formed to surround one or both of a first single-ended metal region and a first power metal region, the second plane metal region is further formed to surround one or both of a second single-ended metal region and a second power metal region, the first single-ended metal region and the second single-ended metal region are bonded together, and / or the first power metal region and the second power metal region are bonded together.

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