Systems and methods for direct bonding in semiconductor die fabrication

Abstract

This application relates to systems and methods for direct bonding in semiconductor die wafer fabrication. A method for bonding semiconductor dies, the resulting semiconductor device, and associated systems and methods are disclosed. In some embodiments, the method includes depositing a first material on a first semiconductor die. The first material has a first outer surface and a first chemical composition at the first outer surface. The method also includes depositing a second material on a second semiconductor die. The second material has a second outer surface and a second chemical composition at the second outer surface that is different than the first chemical composition. The method also includes stacking the dies. The second outer surface of the second semiconductor die is in contact with the first outer surface of the first semiconductor die in the stack. The method also includes reacting the first outer surface with the second outer surface. The reaction bonds the first outer surface to the second outer surface.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 238,084, filed on August 27, 2021, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Methods for determining the bonding strength in materials being joined. Background Technology

[0004] Individual semiconductor dies are typically batch-manufactured on semiconductor wafers and then separated into individual dies. Batch manufacturing processes increase throughput and reduce the difficulty of handling individual semiconductor dies as their size continues to shrink. Individual semiconductor dies can then be stacked to form semiconductor assemblies. Hybrid bonding, sometimes called direct bonding, describes a bonding process between dies without any additional intermediate layers. Hybrid bonding processes typically involve fusion bonding processes (e.g., oxide-oxide bonding) and metal-metal bonding processes, sometimes simultaneously. Fusion bonding and metal-metal bonding often rely on chemical bonds and interactions between the two surfaces. For example, fusion bonding processes for silicon are based on intermolecular interactions involving van der Waals forces, hydrogen bonds, and strong covalent bonds. Direct bonding between surfaces helps semiconductor die manufacturers meet the need to reduce the volume occupied by die assemblies. However, hybrid bonding processes typically require high temperatures to bond the surfaces together uniformly. High temperatures can cause defects in stacked semiconductor devices, for example, where materials with different coefficients of thermal expansion come into contact with each other. Furthermore, the resulting bond may lack the strength required to meet the needs of a complete stacked assembly. Summary of the Invention

[0005] This disclosure provides a method for bonding semiconductor dies, the method comprising: depositing a first dielectric on a first semiconductor die, wherein the first dielectric comprises a first material and a second material in a first molecular ratio at a first surface of the first dielectric; depositing a second dielectric on a second semiconductor die, wherein the second dielectric comprises the first material and the second material in a second molecular ratio different from the first molecular ratio at a second surface of the second dielectric; stacking the second semiconductor die and the first semiconductor die, wherein the first surface is in contact with the second surface; and bonding the first surface to the second surface by diffusing the second material from the second dielectric to the first dielectric.

[0006] Another aspect of this disclosure provides a method for bonding a first semiconductor die to a second semiconductor die, the method comprising: depositing a first material on the first semiconductor die, wherein the first material has a first outer surface and wherein the first material has a first chemical composition at the first outer surface; depositing a second material on the second semiconductor die, wherein the second material has a second outer surface and wherein the second material has a second chemical composition at the second outer surface that is different from the first chemical composition; stacking the second outer surfaces of the second semiconductor die to contact the first outer surface of the first semiconductor die; and reacting the first outer surface with the second outer surface, the reaction bonding the first outer surface to the second outer surface.

[0007] Another aspect of this disclosure provides a stacked semiconductor device comprising: a first semiconductor die; a second semiconductor die disposed above the first semiconductor die; and a bonding layer positioned between the first semiconductor die and the second semiconductor die, the bonding layer comprising: a first portion having a first molecular composition between the first semiconductor die and the second semiconductor die; and a second portion having a second molecular composition different from the first molecular composition between the first portion and the first semiconductor die. Attached Figure Description

[0008] Figure 1A and 1B This illustrates a general hybrid bonding process between two semiconductor dies according to some embodiments of the technology of the present invention.

[0009] Figure 2A-2C The fusion bonding aspect of a hybrid bonding process using reactive dielectrics, according to some embodiments of the technology of the present invention, is illustrated.

[0010] Figures 3A-3C The fusion bonding aspect of a hybrid bonding process using reactive polymers, according to some embodiments of the technology of the present invention, is illustrated.

[0011] Figures 4A-4C This illustrates a fusion bonding aspect of a hybrid bonding process using reactive materials deposited in holes in each semiconductor die, according to some embodiments of the technology of the present invention.

[0012] Figure 5A and 5B The invention illustrates some embodiments of a hybrid bonding process using reactive materials.

[0013] Figure 6This is a top plan view of a semiconductor die with reactive material deposited on it, according to some embodiments of the present invention.

[0014] Figure 7 This is a flowchart illustrating a hybrid bonding process using reactive materials, according to some embodiments of the present invention.

[0015] Figure 8 A schematic diagram of a system comprising a semiconductor die assembly configured according to some embodiments of the present invention.

[0016] The drawings are not necessarily drawn to scale. Similarly, for the purpose of illustrating some embodiments of the invention, some components and / or operations may be divided into different blocks or combined into a single block. Furthermore, while the invention is open to various modifications and alternatives, specific embodiments have been shown in the drawings by way of example and are described in detail below. However, it is not intended to limit the invention to the specific embodiments described. Rather, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. Detailed Implementation

[0017] Overview

[0018] A method and associated system and method for hybrid bonding of semiconductor surfaces, resulting semiconductor devices are disclosed. In some embodiments, the method includes depositing a first material on a first semiconductor substrate (e.g., a first die substrate). The first material has a first outer surface and a first chemical composition at the first outer surface. The method further includes depositing a second material on a second semiconductor substrate (e.g., a second die substrate). The second material has a second outer surface and a second chemical composition at the second outer surface that differs from the first chemical composition. The method further includes stacking the semiconductor substrates such that the second outer surface of the second material contacts the first outer surface of the first material. Once stacked, the method includes reacting the first outer surface with the second outer surface. The reaction bonds the first outer surface to the second outer surface, thereby bonding the first semiconductor substrate to the second semiconductor substrate.

[0019] In some embodiments, the first material and the second material are dielectric materials. The first chemical composition may contain a first molecule to second molecule ratio higher than the stoichiometric equilibrium molecular ratio of the dielectric material; while the second chemical composition may contain a first molecule to second molecule ratio lower than the stoichiometric equilibrium molecular ratio of the dielectric material. When the first material and the second material are stacked, the dielectrics may react to move towards the stoichiometric equilibrium molecular ratio in each dielectric, thereby bonding the dielectrics. In some embodiments, the first material and the second material are polymer-backed colloids. For example, the first material may be a first polymer-backed colloid in which a first molecule of substance is suspended, and the second material may be a second polymer-backed colloid in which a second molecule of substance is suspended. When the first material and the second material are stacked, the first substance may react with the second substance, thereby bonding the first polymer with the second polymer. In some embodiments, the first material and the second material are partially cured polymers having varying crosslinker concentrations. The first material may have a first crosslinker concentration lower than the preferred crosslinker concentration of the polymer, while the second material may have a second crosslinker concentration higher than the preferred crosslinker concentration of the polymer. When the first and second materials are stacked, the first polymer can react with the second polymer to move toward the mentioned crosslinking agent concentration in each polymer, thereby bonding the polymers.

[0020] For ease of reference, the stacked semiconductor device and the method of forming the stacked semiconductor device are sometimes described herein with reference to the top and bottom, upper and lower, upward and downward and / or horizontal plane, xy plane, vertical or z direction relative to the spatial orientation of the embodiments shown in the figures. However, it should be understood that the stacked semiconductor device and the method of forming the stacked semiconductor device can be moved to different spatial orientations and used in different spatial orientations without changing the structure and / or function of the disclosed embodiments of the invention.

[0021] Furthermore, although this document primarily discusses a hybrid bonding process for joining the surfaces of two semiconductor dies to form a stacked semiconductor assembly, those skilled in the art will understand that the scope of the invention is not limited thereto. For example, the disclosed methods can also be used to join any other surfaces in a semiconductor device and / or join surfaces within a semiconductor die. Accordingly, the scope of the invention is not limited to any subset of the embodiments and is limited only to the limitations set forth in the appended claims. Attached Figure Description

[0023] Figure 1A and 1B This illustrates a general hybrid bonding process between stacked semiconductor components 100 (“stacked components 100”) according to some embodiments of the present invention. See also Figure 1AAs shown, in some embodiments, a hybrid bonding process may occur between the first semiconductor die 110 (“first die 110”) and the second semiconductor die 140 (“second die 140”).

[0024] The first die 110 includes a semiconductor substrate 112 having a first surface 114 (e.g., an upper surface) and a second surface 116 (e.g., a lower surface) opposite the first surface 114. Material 120 is deposited on the first surface 114, with a bonding surface 122 facing outwards (e.g., upwards) from the substrate 112. Material 120 insulates the first die 110 and facilitates bonding the first die 110 to the second die 140. As discussed in more detail below, material 120 may be a dielectric material, a polymer-backed colloid, a polymer with a crosslinking agent, and / or various other suitable materials. Examples of usable dielectrics include silicon dioxide, silicon nitride, silicon nitride carbon, polycrystalline silicon, silicon carbonate, and / or any other suitable dielectric. Examples of polymers include polypyrrole, polyaniline, polydopamine, and / or various suitable epoxy resins.

[0025] like Figure 1A The diagram further illustrates that the first die includes an interconnect structure 130 extending from the bonding surface 122 of the material 120 toward a second surface 116 of the substrate 112. In some embodiments, the interconnect structure 130 extends completely from the bonding surface 122 to the second surface 116. In other embodiments, the interconnect structure 130 extends from the bonding surface 122 to a first surface 114 of the substrate 112 and / or to some intermediate depth between the bonding surface 122 and the second surface 116 (e.g., to the first surface 114, to some depth in the substrate 112, etc.). Furthermore, each individual interconnect structure 130 includes a bonding site 132 at the bonding surface 122. As shown, each bonding site 132 is substantially flush with the bonding surface 122 of the material 120, thereby providing a substantially flat surface for bonding with the second die 140.

[0026] In the illustrated embodiment, each bonding site 132 is shown as having a bonding pad shape with a diameter wider than the rest of the corresponding interconnect structure 130. The larger diameter of the bonding site 132 helps facilitate bonding to the corresponding electrical feature in the second die 140 (e.g., the corresponding interconnect structure 160, as discussed below). In some embodiments, each bonding site 132 may have a different size and / or shape. For example, in various embodiments, the bonding site 132 may have a diameter generally corresponding to the diameter of the interconnect structure 130, a varying diameter (e.g., based on its position on the first die 110), and / or a different shape when viewed from above. In some embodiments, each bonding site 132 may be an exposed portion of the interconnect structure 130 at the bonding surface 122.

[0027] In some embodiments, the interconnect structure 130 may be made of copper, nickel, epoxy resin with a conductor filling, and / or other conductive materials. In some embodiments, the interconnect structure 130 may be surrounded by an insulator to electrically isolate the interconnect structure 130 from the substrate 112. In some embodiments, the bonding site 132 may also be made of copper, nickel, epoxy resin with a conductor filling, and / or other conductive materials. In some embodiments, the interconnect structure 130 and the bonding site 132 may be made of the same material (e.g., when the bonding site is a continuation of the interconnect structure). For example, the interconnect structure 130 and the bonding site 132 may both be made of copper. In some such embodiments, the interconnect structure 130 and the bonding site 132 may be formed in a single step. In other embodiments, they may be formed in separate steps. In some embodiments, the interconnect structure 130 and the bonding site 132 may be made of different materials. For example, the interconnect structure 130 may be made of nickel, while the bonding site 132 may be made of copper.

[0028] Similar to the above, the second die 140 includes a semiconductor substrate 142 having a first surface 144 (e.g., a lower surface) and a second surface 146 (e.g., an upper surface) opposite the first surface 144. Material 150 is deposited on the first surface 144, wherein a bonding surface 152 faces outward from the substrate 142. Material 150 insulates the second die 140 and facilitates bonding the second die 140 to the first die 110. Material 150 may correspond to the first material 120, such as a corresponding dielectric, a corresponding polymer, and / or various other suitable materials.

[0029] The second die also includes an interconnect structure 160 extending from the bonding surface 152 of the material 150 toward a second surface 146 of the substrate 142. In some embodiments, the interconnect structure 160 extends completely from the bonding surface 152 to the second surface 146. In other embodiments, the interconnect structure 160 extends from the bonding surface 152 to a first surface 144 and / or some intermediate depth therebetween (e.g., to the first surface 144, to a certain depth in the substrate 142, etc.). Furthermore, each individual interconnect structure 160 includes a bonding site 162 at the bonding surface 152. As shown, each bonding site 162 is substantially flush with the bonding surface 152 of the material 150, thereby providing a substantially flat surface for bonding with the first die 110. In various embodiments, each bonding site 162 may have a diameter substantially corresponding to the diameter of the interconnect structure 160, a varying diameter (e.g., based on its position on the second die 140), may be an exposed portion of the interconnect structure 160 at the bonding surface 152, and / or may have a different shape when viewed from above.

[0030] Furthermore, in various embodiments, the interconnect structure 160 and / or the bonding site 162 may be made of copper, nickel, conductor-filled epoxy resin, and / or other conductive materials. In some embodiments, the interconnect structure 160 may be surrounded by an insulator to electrically isolate the interconnect structure 160 from the substrate 142. In some embodiments, the interconnect structure 160 and the bonding site 162 may be made of the same material (e.g., when the bonding site is a continuation of the interconnect structure). In some embodiments, the interconnect structure 160 and the bonding site 162 may be made of different materials.

[0031] like Figure 1A As indicated by the arrows, the hybrid bonding process involves stacking a second die 140 on the first die 110 to form a stacked assembly 100. Within the stacked assembly 100, as... Figure 1B As shown, material 120 of the first die 110 is in direct contact with material 150 from the second die 140 at the bonding interface 170. In a typical hybrid bonding process, the stack assembly 100 is then heated and subjected to pressure to bond material 120 to material 150 at the bonding interface. In a typical hybrid bonding process, materials 120 and 150 are intentionally non-reactive materials (e.g., inert dielectrics). Non-reactive materials avoid reactions that could reduce the lifetime of the resulting stack assembly, interfere with the performance of the resulting stack assembly, and / or reduce manufacturing throughput. However, non-reactive materials require extremely high temperatures and / or pressures to form a direct bond between the materials, which can have various adverse effects on the components in the stack assembly.

[0032] Alternatively, as discussed in more detail below, the hybrid process of the present invention may include depositing slightly reactive materials and / or layers in the materials to facilitate chemical or physical (e.g., diffusion) reactions occurring at lower temperatures and pressures. In some embodiments, for example, material 120 may be a dielectric with a slightly unbalanced molecular ratio, such as excess silicon in a silicon dioxide dielectric; while material 150 may be a dielectric with a slightly relatively unbalanced molecular ratio, such as excess oxygen in a silicon dioxide dielectric. The excess silicon in material 120 reacts with the excess oxygen in material 150 at a lower temperature to form silicon dioxide. The resulting combined reaction thereby bonds material 120 to material 150 at significantly lower temperatures and pressures, thereby increasing the manufacturing throughput and lifespan of the resulting stacked assembly. The reaction may also produce a much stronger bond than that formed between non-reactive surfaces, thereby further increasing the manufacturing throughput and lifespan of the resulting stacked assembly. As discussed in more detail below, the material used to create the reactive surface between the first die 110 and the second die 140 may comprise various doped dielectrics and / or doped polymers. In some embodiments, the doping amount is also varied depending on the depth within the material.

[0033] Figure 2A-2CThis illustrates a fusion bonding aspect of a hybrid bonding process using reactive dielectrics, according to some embodiments of the technology presented in this invention. (See also: Regarding...) Figure 2A As shown, the stacked component 200 includes components typically described above regarding... Figure 1A and 1B The components discussed are similar to those in the original text. For example, stacked assembly 200 includes a first die 210 and a second die 240. The first die 210 includes a semiconductor substrate 212 and has a first surface 214 and a second surface 216 opposite to the first surface. A first dielectric 220 is disposed on the first surface 214 of the substrate 212. Similarly, the second die 240 includes a semiconductor substrate 242 and has a first surface 244 and a second surface 246 opposite to the first surface 244. A second dielectric 250 is disposed on the first surface 244 of the substrate 242. Interconnect structures 130, 160 (e.g., omitted) Figure 1A and 1B (This is to avoid confusing the arguments in this article.)

[0034] The first dielectric 220 includes a bonding surface 222 facing outwards from the first die 210. The bonding surface 222 has a first chemical composition having a molecular ratio that deviates at least partially from the stoichiometric equilibrium molecular ratio of the dielectric. For example, the first dielectric 220 may be silicon dioxide having a stoichiometric equilibrium ratio of one silicon per two oxygen atoms (represented herein as SiO2), while the bonding surface 222 may contain fewer than two oxygen atoms per silicon atom. In various embodiments, for example, the dielectric may contain approximately one oxygen atom per silicon atom (represented herein as SiO1), approximately 1.5 oxygen atoms per silicon atom (represented herein as SiO2), or approximately 1.5 oxygen atoms per silicon atom (represented herein as SiO2). 1.5 (This is represented by the symbol), each silicon has approximately 1.8 oxygen atoms (this article uses SiO2). 1.8 (This is represented by the symbol), each silicon has approximately 1.9 oxygen atoms (this article uses SiO2). 1.9 (represented by) approximately 1.95 oxygen atoms per silicon (in this article, SiO2 is used to represent) 1.95 (represented as) or approximately 1.99 oxygen atoms per silicon (in this text, represented by SiO₂) 1.99 (Indicated). As a result, the first dielectric 220 contains unbonded silicon molecules at the bonding surface 222, which can be used to react with suitable substances.

[0035] The second dielectric 250 includes a bonding surface 252 facing outwards from the second die 240. The bonding surface 252 has a second chemical composition having a molecular ratio that deviates at least partially from the stoichiometric equilibrium molecular ratio of the dielectric. The second chemical composition deviates from the stoichiometric equilibrium ratio in the opposite direction to the first chemical composition. Returning to the above example, the second dielectric 250 may be silicon dioxide, wherein the bonding surface 252 contains more than two oxygen atoms per silicon. For example, in some embodiments, the bonding surface 252 may contain about three oxygen atoms per silicon (represented herein by SiO3), about 2.5 oxygen atoms per silicon (represented herein by SiO2), or more than 2.5 oxygen atoms per silicon. 2.5 (represented by) approximately 2.2 oxygen atoms per silicon (in this article, SiO2 is used to represent) 2.2 (represented by) approximately 2.1 oxygen atoms per silicon (in this article, SiO2 is used to represent) 2.1 (represented by) approximately 2.05 oxygen atoms per silicon (in this article, SiO2 is used to represent) 2.05 (represented) or approximately 2.01 oxygen atoms per silicon (in this paper, represented by SiO₂) 2.01 (Indicated). As a result, the second dielectric 250 contains unbonded oxygen molecules at the bonding surface 252, which can be used to react with suitable substances.

[0036] In the illustrated embodiment, the first dielectric 220 and the second dielectric 250 have sublayers with corresponding chemical compositions at the bonding surfaces 222, 252. In some embodiments, the corresponding chemical composition is present throughout the first dielectric 220 and the second dielectric 250. In some embodiments, the first dielectric 220 and the second dielectric 250 include a transition (e.g., gradient, gradation, or other suitable transition) between the chemical composition at the bonding surfaces 222, 252 and the chemical composition of the adjacent first die 210 and the second die 240. For example, in some embodiments, the first dielectric 220 has a stoichiometric imbalance molecular ratio at the bonding surface 222, a stoichiometric balance molecular ratio in the vicinity of the substrate 212, and a transition (e.g., gradient) between the substrate 212 and the bonding surface 222.

[0037] In some embodiments, the first dielectric 220 and the second dielectric 250 can be deposited by varying a typical chemical vapor deposition (“CVD”) process. In such embodiments, a stoichiometric imbalance in molecular ratios can be created in the dielectric by varying the gas ratios during vapor deposition. Returning to the silicon dioxide example, the ratio of silicon particles to oxygen can be intentionally varied to leave unbonded oxygen and / or silicon in the resulting dielectric layer. In some embodiments, the CVD process can be varied stepwise to produce a first sublayer with a stoichiometric balance molecular ratio and a second sublayer with a stoichiometric imbalance molecular ratio. In some embodiments, the CVD process can be varied dynamically to transition from a stoichiometric balance molecular ratio to a stoichiometric imbalance molecular ratio.

[0038] In some embodiments, the first dielectric 220 and the second dielectric 250 can be deposited by modifying a typical spin-coating process (e.g., a spin-coating dielectric process or a spin-coating glass process). For example, the ratio of materials used during spin-coating can be intentionally changed to increase the silicon-to-oxygen ratio and / or increase the oxygen-to-silicon ratio. In some embodiments, the spin-coating process may include varying the curing temperature of the spin-coated material, which affects the molecular ratios set in the dielectric near the dielectric surface. Returning to the silica example, the spin-coating process may include depositing a silica precursor and curing the precursor in the presence of oxygen to form silica. By varying the curing temperature, the spin-coating process can reduce the number of silica molecules forming in the precursor, leaving a stoichiometric imbalance in the molecular ratio of silica molecules and silica material. In some embodiments, the curing temperature can be varied stepwise to produce a first sublayer with a stoichiometric balance molecular ratio and a second sublayer with a stoichiometric imbalance molecular ratio. In some embodiments, the curing temperature can be varied dynamically to cause a transition from a stoichiometric balance molecular ratio to a stoichiometric imbalance molecular ratio.

[0039] Such as about Figure 2B As shown, the hybrid bonding process includes stacking a second die 240 on a first die 210, wherein a first dielectric 220 and a second dielectric 250 are in contact at a bonding interface 270. Once stacked, the hybrid bonding process allows a portion of the first dielectric 220 to react with a portion of the second dielectric 250 in a region 272 adjacent to the bonding interface 270. For example, in embodiments where the first dielectric 220 and the second dielectric 250 are silicon dioxide deviating from the stoichiometric ratio (SiO2) in opposite directions, the hybrid bonding process may include reacting unbonded silicon molecules with unbonded oxygen molecules to form silicon dioxide.

[0040] In some embodiments, the reaction is exothermic, causing the first dielectric 220 and the second dielectric 250 to react upon contact. For example, the reaction may be exothermic, thus releasing a small amount of heat during the reaction. In some embodiments, the reaction is endothermic and requires some activation energy to initiate. In such embodiments, the hybrid bonding process may include providing activation energy to the stacked dies. For example, the hybrid bonding process may include providing a small amount of heat to activate the reaction, electroactivation energy, providing a small amount of pressure to the stacked dies, and / or any other suitable form of activation energy. In some embodiments, the hybrid bonding process may include providing energy (e.g., heat, electricity, and / or pressure) as a catalyst for the reaction. For example, the hybrid bonding process may include providing an electrocatalyst that accelerates the reaction to form a bond between the first dielectric 220 and the second dielectric 250.

[0041] During the reaction, molecules in the first dielectric 220 bind to molecules in the second dielectric 250, causing the molecular ratio in region 272 to align with the stoichiometric equilibrium ratio of the dielectrics. As a result, a portion of the molecules from the first dielectric 220 can move into the second dielectric 250, and / or a portion of the molecules from the second dielectric 250 can move into the first dielectric 220 (e.g., thereby diffusing material from the first dielectric 220 to the second dielectric and vice versa). The combination of molecular movement between the first dielectric 220 and the second dielectric 250 and molecular movement along the bonding interface 270 creates a strong bond between the first dielectric 220 and the second dielectric 250.

[0042] Examples of reaction results Figure 2C As shown, molecular combination and movement between the first dielectric 220 and the second dielectric 250 cause the first dielectric 220 and the second dielectric 250 to bond in region 274 to form a continuous dielectric 280. In the illustrated embodiment, the reaction proceeds along the bonding interface 270 ( Figure 2B This allows the first dielectric 220 and the second dielectric 250 to fully bond, causing the bonding interface 270 to disappear. In some embodiments, as described below... Figure 6 In more detail, the first dielectric 220 and the second dielectric 250 can be coupled along their respective bonding surfaces 222, 252. Figure 2A The molecular ratio can be changed at a predefined location, leaving unbonded regions in the unchanged regions. For example, a first dielectric 220 and a second dielectric 250 can be bonded between interconnect structures to avoid interference from reactions that could affect the electrical connections between the interconnect structures.

[0043] like Figure 2C As further shown, in some embodiments, the reaction leaves trace amounts of the pre-reacted chemical composition within the first dielectric 220 and the second dielectric 250. That is, although dielectric 280 can have a stoichiometric molecular ratio within region 274, the distance from the bonding interface 270 ( Figure 2B Further regions may not react completely (or at all), leaving regions with the previous molecular ratio. Returning to the silicon dioxide example, region 276 may still contain more than one silicon for every two oxygen atoms, while region 278 may still contain more than two oxygen atoms for every silicon atom. In some embodiments, the reaction may completely consume the excess molecules, leaving only the stoichiometric balance ratio in dielectric 280.

[0044] Figures 3A-3C This illustrates a fusion bonding aspect of a hybrid bonding process using reactive polymers, according to some embodiments of the technology presented in this invention. (See also: Regarding...) Figure 3A As shown, the stacked component 300 includes components typically described above regarding... Figure 1A and 1BThe components discussed are similar to those in the original text. For example, stacked assembly 300 includes a first die 310 and a second die 340. The first die 310 includes a semiconductor substrate 312 and has a first surface 314 and a second surface 316 opposite to the first surface. A first polymer material 320 is disposed on the first surface 314 of the substrate 312. Similarly, the second die 340 includes a semiconductor substrate 342 and has a first surface 344 and a second surface 346 opposite to the first surface. A second polymer material 350 is disposed on the first surface 344 of the substrate 342. Interconnect structures 130, 160 (e.g., omitted) are omitted. Figure 1A (This is to avoid confusing the arguments in this article.)

[0045] The first polymer material 320 includes a bonding surface 322 facing outwards (e.g., upwards) from the first die 310. The first polymer material 320 has a chemical composition at the bonding surface 322. Similarly, the second polymer material 350 includes a bonding surface 352 facing outwards (e.g., downwards) from the second die 340. The second polymer material 350 has a chemical composition at the bonding surface 352 that is different from the chemical composition at the bonding surface 322.

[0046] For example, in some embodiments, the first polymer material 320 and the second polymer material 350 are colloids. The first polymer material 320 may contain a first molecule (e.g., chemical substance 'A') suspended within the polymer, while the second polymer material 350 may contain a second molecule (e.g., chemical substance 'B') suspended within the polymer, the second molecule being reactive upon exposure to the first molecule. In some embodiments, for example, exposing the second chemical substance to the first chemical substance may cause a combined reaction that produces a third molecule suspended within the polymer (e.g., A + B → AB).

[0047] In some embodiments, the first polymer material 320 and the second polymer material 350 are partially cured polymers, and their crosslinking agent concentrations differ from the preferred crosslinking agent concentrations of the polymer materials. In some such embodiments, the crosslinking agent concentration of the first polymer material 320 is lower than the preferred crosslinking agent concentration, while the crosslinking agent concentration of the second polymer material 350 is higher than the preferred crosslinking agent concentration. Examples of polymers that can be used in the crosslinking agent embodiments include polypyrrole, polyaniline, polydopamine, and / or various suitable epoxy resins.

[0048] In some embodiments, the first polymer material 320 and the second polymer material 350 have sublayers with corresponding chemical compositions at the bonding surfaces 322, 352. In some embodiments, the corresponding chemical compositions are present throughout the first polymer material 320 and the second polymer material 350. In some embodiments, the first polymer material 320 and the second polymer material 350 include a transition (e.g., gradient, gradation, or other suitable transition) between the chemical composition at the bonding surfaces 322, 352 and the chemical composition of the adjacent first die 310 and second die 340. For example, in some embodiments, the crosslinker concentration of the first polymer material 320 is lower than the preferred crosslinker concentration of the polymer at the bonding surface 322 and the preferred crosslinker concentration of the adjacent first die 310, and the first polymer material undergoes a transition between the first die 310 and the bonding surface 322.

[0049] Such as about Figure 3B As shown, the hybrid bonding process includes stacking a second die 340 on a first die 310, with the first polymer material 320 and the second polymer material 350 contacting at a bonding interface 370. (This is related to the above...) Figure 2B Similarly, once stacked, the hybrid bonding process includes causing a portion of the first polymer material 320 and a portion of the second polymer material 350 to react within a region 372 adjacent to the bonding interface 370. For example, in embodiments where the first polymer material 320 and the second polymer material 350 are colloids, the hybrid bonding process includes causing molecules suspended in the first polymer material 320 to react with molecules suspended in the second polymer material 350.

[0050] In some embodiments, the reaction is exothermic, causing the first polymer material 320 and the second polymer material 350 to react upon contact. In other embodiments, the reaction is endothermic and requires some activation energy to initiate. Accordingly, the hybrid bonding process may include providing activation energy to the stacked assembly 300. For example, the hybrid bonding process may include providing thermal energy, electrical energy, compressive pressure, and / or any other suitable form of activation energy. In some embodiments, the hybrid bonding process may include providing energy (e.g., heat, electricity, and / or pressure) as a catalyst for the reaction. For example, the hybrid bonding process may include providing an electrocatalyst that accelerates the reaction to form a bond between the first polymer material 320 and the second polymer material 350.

[0051] Examples of reaction results Figure 3CAs shown, molecular combination and movement between the first polymer material 320 and the second polymer material 350 cause the first polymer material 320 and the second polymer material 350 to bond in region 274 to form a continuous polymer material 380. In the illustrated embodiment, the reaction proceeds along the bonding interface 370. Figure 3B This allows the first polymer material 320 and the second polymer material 350 to be fully bonded. In some embodiments, as described below... Figure 6 As discussed, the bonding surfaces 322 and 352 of the first polymer material 320 and the second polymer material 350 may have predefined bonding areas and predefined non-bonding areas.

[0052] In some embodiments, the reaction leaves trace amounts of the pre-reacted chemical composition within the first polymer material 320 and the second polymer material 350. For example, although the polymer material 380 can achieve a preferred crosslinking agent concentration within region 372, the distance from the bonding interface 370 ( Figure 3B Further regions may not react completely (or not at all), leaving regions with the previous chemical composition. For example, the crosslinker concentration in region 376 may still be lower than the preferred crosslinker concentration, while the crosslinker concentration in region 378 may still be higher than the preferred crosslinker concentration. In some embodiments, the reaction may completely consume the reactive components, such that the polymer material 380 is generally homogeneous between the first die 310 and the second die 340.

[0053] Figures 4A-4C This illustrates a fusion bonding aspect of a hybrid bonding process using reactive materials deposited in holes in each semiconductor die, according to some embodiments of the technology presented in this invention. (See also: Regarding...) Figure 4A As shown, the stacked component 400 includes components typically described above regarding... Figure 1A and 1B The components discussed are similar to those in the original text. For example, stacked assembly 400 includes a first die 410 and a second die 440. The first die 410 includes a semiconductor substrate 412 and has a first surface 414 and a second surface 416 opposite to the first surface. A first material 420 is disposed on the first surface 414 of the substrate 412. Similarly, the second die 440 includes a semiconductor substrate 442 and has a first surface 444 and a second surface 446 opposite to the first surface 444. A second material 450 is disposed on the first surface 444 of the substrate 442. Interconnect structures 130, 160 (e.g., omitted) are also omitted. Figure 1A (This is to avoid confusing the arguments in this article.)

[0054] like Figure 4AAs shown, the first material 420 may include one or more holes 426 at the bonding surface 422 of the first material 420, and one or more holes 426 below the bonding surface 422. The first material 420 may be a dielectric, polymer, or other suitable material. The holes 426 are caused by errors during manufacturing and are typically defects in the material that should be carefully avoided. The hybrid bonding process of the present invention may include intentionally allowing the formation of holes 426 and then doping the holes 426 with a chemical composition (e.g., chemical substance 'A') instead of avoiding the holes. Similarly, the second material 450 may include one or more holes 456 located at the bonding surface 452 of the second material 450, and one or more holes 456 below the bonding surface 452. In various embodiments, the second material 450 may also be a dielectric, polymer, or other suitable material. Furthermore, the hybrid bonding process may include intentionally allowing the formation of holes 456 and then doping the holes 456 with a chemical composition (e.g., chemical substance 'B' that reacts with chemical substance A). In some embodiments, for example, exposing a second chemical substance to a first chemical substance can cause a combinatorial reaction (e.g., A+B→AB).

[0055] like Figure 4B As shown, once the vias 426 and 456 are formed and doped, the hybrid bonding process includes stacking a second die 440 on a first die 410, wherein the first material 420 and the second material 450 are in contact at a bonding interface 470. Once stacked, the hybrid bonding process includes causing the chemicals deposited in the vias 426 and 456 to react at the bonding surfaces 422 and 452. In some embodiments, the reaction is exothermic. In other embodiments, the reaction is endothermic and requires some activation energy to initiate. Accordingly, the hybrid bonding process may include providing activation energy to the stack assembly 400. For example, the hybrid bonding process may include providing thermal energy, electrical energy, compressive pressure, and / or any other suitable form of activation energy. In some embodiments, the hybrid bonding process may include providing energy (e.g., heat, electricity, and / or pressure) as a catalyst for the reaction. For example, the hybrid bonding process may include providing an electrocatalyst that accelerates the reaction to form a bond between the first material 420 and the second material 450.

[0056] The reaction causes a portion of the first material 420 and a portion of the second material 450 to bond within region 472 adjacent to the bonding interface 470. For example, the heat released by the reaction may cause a portion of the first material 420 to migrate into the second material 450; a portion of the second material 450 to migrate into the first material 420; and / or cause chemicals deposited in the pores 426, 456 to form an internal bonding structure that facilitates bonding the first material 420 and the second material 450 together.

[0057] Such as about Figure 4CAs shown, the reaction results in a stacked assembly 400, which includes a substrate 412 of a first die 410, a substrate 442 of a second die 440 supported by the substrate 412, and an adhesive bonding material 480 between the substrates 412 and 442. The adhesive bonding material 480 is attached to a first surface 414 of the substrate 412 and a first surface 444 of the substrate 442, thereby forming a direct bond between the first die 410 and the second die 440. In some embodiments, the bonding material 480 includes buried vias adjacent to the substrate 412, the buried vias containing unreacted material of a first chemical composition. In some embodiments, the bonding material 480 includes buried vias adjacent to the substrate 442, the buried vias containing unreacted material of a second chemical composition. In some embodiments, the reaction completely consumes the first and second chemical compositions, such that the bonding material 480 includes buried vias containing reaction products.

[0058] In some embodiments, such as Figure 4C As shown, the bonding material 480 does not include the previous bonding interface 470. Figure 4B Trace amounts of ). In other embodiments, the bonding material 480 includes regions retained in the bonding interface 470. For example, as described below regarding Figure 6 In more detail, the first material 420 and the second material 450 ( Figure 4A Each of the following can have a predefined reactive region doped with a chemical composition to induce a reaction, and a predefined non-reactive region that does not react when the first die 410 and the second die 440 are stacked. In some embodiments, the non-reactive region comprises a hole doped with a non-reactive chemical composition. In some embodiments, the non-reactive region is formed without a hole to be doped.

[0059] Figure 5A and 5B This illustration depicts a hybrid bonding process using reactive materials, representing some embodiments of the invention. Further details regarding the hybrid bonding process are referenced below. Figure 7 As stated above.

[0060] Such as about Figure 5A As shown, the stacked component 500 contains components typically related to those mentioned above. Figure 1A and 1BThe components discussed are similar. For example, stacked assembly 500 includes a first die 510 and a second die 540. The first die 510 includes a semiconductor substrate 512 and has a first surface 514 and a second surface 516 opposite to the first surface. A first material 520 is disposed on the first surface 514 of the substrate 512. The first material 520 includes a bonding surface 522 having a first chemical composition. Similarly, the second die 540 includes a semiconductor substrate 542 and has a first surface 544 and a second surface 546 opposite to the first surface. A second material 550 is disposed on the first surface 544 of the substrate 542. The second material 550 includes a bonding surface 552 having a second chemical composition different from the first chemical composition.

[0061] As discussed in detail above, the first chemical composition of the first material 520 can react with the second chemical composition of the second material 550. A hybrid bonding process can utilize the reaction between the chemical compositions to bond the first material 520 and the second material 550. Therefore, the hybrid bonding process includes stacking a second die 540 on the first die 510 to form a stacked assembly 500. Figure 5A As shown, the stacking process may include an alignment step that ensures that the bonding sites 532 of the interconnect structure 530 in the first die 510 are aligned with the corresponding bonding sites 562 of the interconnect structure 560 in the second die 540 of the stacked assembly 500.

[0062] Figure 5B The result of the hybrid bonding process is shown. As illustrated, the reaction results in a stacked assembly 500, which includes a substrate 512 of a first die 510, a substrate 542 of a second die 540 supported by the substrate 512, and an adhesive bonding material 580 between the substrates 512 and 542. The bonding material 580 is attached to a first surface 514 of the substrate 512 and a first surface 544 of the substrate 542, thereby forming a direct bond between the first die 510 and the second die 540.

[0063] like Figure 5B As further shown, a single interconnect structure 530 from the first die 510 and a single interconnect structure 560 from the second die 540 are in contact within the bonding material 580. In the illustrated embodiment, interconnect structures 530, 560 are in contact with each other at the remaining bonding interface 570. In some embodiments, the heat generated by the reaction can anneal the interconnect structures 530, 560, thereby further strengthening the bonding between the first die 510 and the second die 540. In some embodiments where the bonding interface 570 remains between the interconnect structures 530, 560, the hybrid bonding process may then include an annealing process to fully bond the interconnect structures 530, 560 at the bonding interface 570. For example, the hybrid bonding process may include heating the stacked assembly 500 to a reflow temperature.

[0064] Figure 6 This is a top plan view of a semiconductor die 610 with material 620 deposited on it, according to some embodiments of the present invention. In the illustrated embodiments, material 620 includes an upper surface 622 with a central bonding region 624, an interconnect region 626 surrounding bonding sites 632 for interconnection within the die 610, and a peripheral bonding region 628. The chemical composition of material 620 can vary depending on the regions of the upper surface 622. For example, in some embodiments, the central bonding region 624 and the peripheral bonding region 628 may have reactive chemical compositions (e.g., as described above regarding...). Figure 2A-5B (Any reactive component discussed), while interconnect region 626 may have a generally non-reactive chemical composition (e.g., inert dielectric, cured polymer or other suitable material).

[0065] As a result, when die 610 is stacked on top of another die with corresponding regions, the hybrid bonding process allows the material in the central bonding region 624 and the peripheral bonding region 628 to react with the corresponding regions on the stacked dies to form a bond, while the interconnect region 626 remains non-reactive. In various embodiments, the upper surface 622 may include various other divisions into reactive and non-reactive regions. These divisions may be predetermined based on desired locations for reaction (e.g., spaced apart from vulnerable components, such as corroded bonding sites), desired locations for increased bond strength, and / or the convenience of depositing reactive chemical compositions during manufacturing.

[0066] Figure 7 This is a flowchart of a hybrid bonding process using reactive materials, according to some embodiments of the present invention. At block 705, process 700 includes depositing a first material on a first die substrate. As discussed in detail above, the first material may have a first chemical composition at its outer surface. In some embodiments, the first material has a first chemical composition throughout the entire first material. In some embodiments, the first material has a first chemical composition at a sublayer adjacent to the outer surface. In some embodiments, the first material has a chemical composition gradient from an inner surface adjacent to the first die substrate to an outer surface. As further discussed above, the first material may be a dielectric, a polymer-supported colloid, a polymer with a crosslinking agent concentration, or any other suitable material. Purely by way of example, if the first material is a dielectric, block 705 may include a CVD process in which different gas ratios are used.

[0067] At block 710, process 700 includes depositing a second material on a second die substrate. As discussed in detail above, the second material may have a second chemical composition at its outer surface that differs from the first chemical composition. In some embodiments, the second material has a second chemical composition throughout the entire second material. In some embodiments, the second material has a second chemical composition in a sublayer adjacent to the outer surface. In some embodiments, the second material has a chemical composition gradient from an inner surface adjacent to the second die substrate to the outer surface of the second material. In some embodiments, the second chemical composition reacts in the opposite direction to the first chemical composition. For example, if the first material is a polymer backing colloid in which a first substance A is suspended, the second material may be a polymer backing colloid in which a second substance B that reacts with the first substance A is suspended.

[0068] At block 715, process 700 includes stacking a first die and a second die such that the outer surface of the first material contacts the outer surface of the second material. In some embodiments, the first die includes at least one first electrical feature (e.g., an interconnect structure), while the second die includes at least one second electrical feature (e.g., an interconnect structure). The first electrical feature may have an exposed portion at the outer surface of the first material, and the electrical feature structure may have an exposed portion at the outer surface of the second material. In such embodiments, block 715 may include aligning the exposed portions of the first electrical feature with the exposed portions of the second electrical feature.

[0069] At block 720, process 700 includes fused and metal-to-metal bonded stacked dies. As discussed above, each die comprises a material having an outer surface with a chemical composition. A first chemical composition and a second chemical composition react with each other. Therefore, process 700 includes inducing a reaction between the first and second chemical compositions to melt the first and second materials in order to bond the stacked dies. In some embodiments, the reaction is exothermic, causing the outer surfaces of the stacked dies to react upon contact. In some such embodiments, the reaction is exothermic and releases a small amount of heat, further promoting bonding between the outer surfaces of the stacked dies. In some embodiments, the reaction is endothermic and requires some activation energy to initiate. In various such embodiments, block 720 includes heating the stacked dies, providing electro-activation energy to the stacked dies, applying a small amount of pressure to the stacked dies, and / or providing any other suitable form of activation energy. In some embodiments, block 720 may include supplying excess energy (e.g., heat, electricity, and / or pressure) as a catalyst for the reaction. As discussed above, when molecules migrate between two materials to react, the result of the reaction is a strong bond between the two materials.

[0070] In some embodiments, alignment at block 715 brings the exposed portions of the electrical features into contact with each other, thereby establishing an electrical connection between the electrical features. Because the strong bond between the first and second materials will hold the two substrates in place, in some embodiments, process 700 is completed after the surfaces are bonded together. In the illustrated embodiment, process 700 includes annealing the electrical features at optional block 725 to further establish an electrical connection between them. Annealing the electrical features may involve heating the stacked dies to induce a small amount of reflow between the two electrical features. Annealed electrical features can maintain a strong electrical connection for the lifespan of the final stacked dies. In some embodiments, annealed electrical features can also further enhance the bonding strength between the stacked dies.

[0071] Figure 8 A schematic diagram of a system comprising a semiconductor die assembly configured according to an embodiment of the present invention. (Referring to the above references) Figure 1A-7 Any of the semiconductor devices with the described features can be incorporated into any of a large number of larger and / or more complex systems, a representative example of which is... Figure 8 The system 900 is schematically shown in the diagram. System 900 may include a memory 990 (e.g., SRAM, DRAM, flash memory, and / or other memory devices) as generally described above, a power supply 992, a drive 994, a processor 996, and / or other subsystems or components 998. (See above reference) Figure 1A-7 The described semiconductor device may be included Figure 8 In any of the elements shown. For example, memory 990 may contain elements according to the above description. Figure 7 The described process involves stacking semiconductor dies. The resulting system 900 can be configured to perform any of a wide variety of suitable computing, processing, storage, sensing, imaging, and / or other functions. Accordingly, representative examples of system 900 include, but are not limited to, computers and / or other data processors, such as desktop computers, laptop computers, network appliances, handheld devices (e.g., palmtop computers, wearable computers, cellular or mobile phones, personal digital assistants, music players, etc.), tablet computers, multiprocessor systems, processor-based or programmable consumer electronics devices, network computers, and microcomputers. Additional representative examples of system 900 include lights, cameras, vehicles, etc. With respect to these and other examples, system 900 can be housed in a single unit or distributed across multiple interconnected units, for example, via a communication network. Accordingly, components of system 900 can include local and / or remote memory storage devices and any of a wide variety of suitable computer-readable media.

[0072] Example

[0073] For example, the present invention is illustrated according to various aspects described below. For convenience, various embodiments of aspects of the present invention are described as numbered embodiments (1, 2, 3, etc.). These provisions are provided as embodiments but do not limit the present invention. It should be noted that any dependent embodiments may be combined in any suitable manner and placed in the respective independent embodiments. Other embodiments may be presented in a similar manner.

[0074] 1. A method for bonding semiconductor dies, the method comprising:

[0075] A first dielectric is deposited on a first semiconductor die, wherein the first dielectric comprises a first material and a second material in a first molecular ratio at a first surface of the first dielectric;

[0076] A second dielectric is deposited on a second semiconductor die, wherein the second dielectric comprises the first material and the second material having a second molecular ratio different from the first molecular ratio at a second surface of the second dielectric;

[0077] Stacking the second semiconductor die and the first semiconductor die, wherein the first surface is in contact with the second surface; and

[0078] The first surface is bonded to the second surface by diffusing the second material from the second dielectric to the first dielectric.

[0079] 2. The method according to Example 1, wherein bonding the first surface to the second surface includes an exothermic reaction, and wherein the first molecular ratio and the second molecular ratio are stoichiometrically disequilibrium ratios.

[0080] 3. The method according to any one of Embodiments 1 and 2, wherein the first dielectric comprises a third surface opposite to the first surface contacting the first die, wherein the first dielectric comprises the first material and the second material having a third molecular ratio at the third surface that is different from the first molecular ratio, and wherein the first dielectric comprises a central portion having a molecular ratio gradient from the third molecular ratio adjacent to the third surface to the first molecular ratio adjacent to the first surface.

[0081] 4. The method according to any one of embodiments 1 to 3, wherein:

[0082] The first semiconductor die includes a first interconnect, wherein a portion of the first interconnect is at least partially exposed at the first surface;

[0083] The second semiconductor die includes a second interconnect, a portion of which is exposed at the second surface; and

[0084] The method further includes:

[0085] Align the exposed portion of the first interconnect with the exposed portion of the second interconnect; and

[0086] The exposed portions of the first interconnect and the second interconnect are annealed to form an electrical connection between the first interconnect and the second interconnect.

[0087] 5. The method according to any one of embodiments 1 to 4, wherein the first surface is joined with the second surface to include a first semiconductor die and a second semiconductor die that are heated and stacked to initiate the diffusion.

[0088] 6. The method according to any one of Embodiments 1 to 5, wherein reacting the surface of the first dielectric with the second surface of the second dielectric comprises providing an electrocatalyst to the stacked first and second semiconductor dies to initiate the diffusion.

[0089] 7. The method according to any one of embodiments 1 to 6, wherein depositing the first dielectric on the first semiconductor die comprises a chemical vapor deposition process, and wherein during the chemical vapor deposition process, the chemical vapor ratio is changed to deposit the first material and the second material in the first molecular ratio on the first surface.

[0090] 8. The method according to Example 7, wherein the chemical vapor deposition process is a first chemical vapor deposition process, wherein the chemical gas ratio is a first chemical gas ratio, wherein depositing the second dielectric on the second semiconductor die includes a second chemical vapor deposition process, and wherein the second chemical gas ratio is changed during the second chemical vapor deposition process, which is opposite to the first chemical vapor deposition process, to deposit the first material and the second material in the second molecular ratio at the second surface.

[0091] 9. The method according to any one of embodiments 1 to 8, wherein depositing the first dielectric on the first semiconductor die comprises a spin coating process to deposit a spin-coated dielectric, and wherein the deposition material ratio is varied during the spin coating process to deposit the first material and the second material in the first molecular ratio at the first surface.

[0092] 10. The method according to any one of embodiments 1 to 9, wherein:

[0093] The first material is silicon, and the second material is oxygen;

[0094] Compared to silicon dioxide in stoichiometric equilibrium, the first molecule contains less oxygen.

[0095] Compared to silicon dioxide in stoichiometric equilibrium, the second molecule contains more oxygen; and

[0096] The bonding causes oxygen to migrate from the second dielectric to the first dielectric.

[0097] 11. A method for bonding a first semiconductor die to a second semiconductor die, the method comprising:

[0098] A first material is deposited on the first semiconductor die, wherein the first material has a first outer surface, and wherein the first material has a first chemical composition at the first outer surface;

[0099] A second material is deposited on the second semiconductor die, wherein the second material has a second outer surface, and wherein the second material has a second chemical composition at the second outer surface that is different from the first chemical composition;

[0100] The second outer surface of the second semiconductor die is stacked to contact the first outer surface of the first semiconductor die; and

[0101] The first outer surface reacts with the second outer surface, and the reaction causes the first outer surface to bond to the second outer surface.

[0102] 12. The method according to Example 11, wherein:

[0103] The first semiconductor die includes a first interconnect having an exposed portion at the first outer surface and an embedded portion within the first semiconductor die;

[0104] The second semiconductor die includes a second interconnect having an exposed portion at the second outer surface and a substrate-penetrating portion within the second semiconductor die; and

[0105] The method further includes:

[0106] Prior to the reaction, the exposed portion of the first interconnect is aligned with the exposed portion of the second interconnect; and

[0107] The exposed portions of the first interconnect and the second interconnect are annealed to form an electrical connection between the first interconnect and the second interconnect.

[0108] 13. The method according to any one of embodiments 11 and 12, wherein:

[0109] The first material and the second material include silicon-based dielectric materials;

[0110] Compared to the silicon ratio in the stoichiometric equilibrium of the dielectric material, the first chemical composition contains a higher silicon ratio; and

[0111] The second chemical composition contains a lower silicon ratio compared to the silicon ratio in the stoichiometric equilibrium of the dielectric material.

[0112] 14. The method according to any one of embodiments 11 and 12, wherein:

[0113] The first material comprises a first polymer backing colloid in which a first molecule is suspended; and

[0114] The second material comprises a second polymer backing colloid in which second molecules are suspended.

[0115] The first and second molecular substances are exothermic and reactive, and the reaction produces a third polymer backing colloid in which a third molecular substance is suspended.

[0116] 15. The method according to any one of embodiments 11 and 12, wherein:

[0117] The first material comprises a partially cured polymer, the partially cured polymer having a first crosslinking agent concentration lower than the preferred crosslinking agent concentration of the polymer; and

[0118] The second material comprises the partially cured polymer, the partially cured polymer having a second crosslinking agent concentration higher than the preferred crosslinking agent concentration of the polymer.

[0119] 16. The method according to any one of the embodiments 11 to 15, wherein after the reaction, the first outer surface of the first material and the second outer surface of the second material have a third chemical composition, wherein the third chemical composition does not react with the first chemical composition and the second chemical composition.

[0120] 17. A stacked semiconductor device comprising:

[0121] First Semiconductor Die;

[0122] A second semiconductor die is disposed above the first semiconductor die;

[0123] A bonding layer, positioned between the first semiconductor die and the second semiconductor die, the bonding layer comprising:

[0124] The first part, situated between the first semiconductor die and the second semiconductor die, has a first molecular composition; and

[0125] The second part, located between the first part and the first semiconductor die, has a second molecular composition that is different from the first molecular composition.

[0126] 18. The stacked semiconductor device according to Example 17, wherein the bonding layer is a silicon dioxide dielectric, wherein the first molecular composition has a molecularly balanced silicon-oxygen ratio, and wherein the second molecular composition contains less oxygen compared to the molecularly balanced silicon-oxygen ratio.

[0127] 19. The stacked semiconductor device according to any one of embodiments 17 and 18, wherein:

[0128] The bonding layer is a polymer-backed colloid layer;

[0129] The second portion of the bonding layer has a first molecule suspended therein;

[0130] The bonding layer further comprises a third portion having a second molecule suspended therein, located between the first portion and the second semiconductor die; and

[0131] The first portion of the bonding layer has a third molecule suspended therein, the third molecule being a product of the reaction between the first molecule and the second molecule.

[0132] 20. The stacked semiconductor device according to any one of embodiments 17 to 19:

[0133] The bonding layer is a polymer substrate with a crosslinking agent;

[0134] The first portion of the bonding layer has a first concentration of the crosslinking agent;

[0135] The second portion of the bonding layer has a second concentration of the crosslinking agent that is different from the first concentration.

[0136] in conclusion

[0137] Based on the foregoing, it should be understood that specific embodiments of the present technology have been described herein for illustrative purposes, but well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of embodiments of the present technology. In the event of any conflict between any material incorporated herein by reference and this disclosure, this disclosure shall prevail. Singular or plural terms may also include plural or singular terms, respectively, where the context permits. Furthermore, unless the word “or” is expressly limited to meaning only a single item exclusive to other items in a list referring to two or more items, the use of “or” in this list may be understood to include: (a) any single item in the list, (b) all items in the list, or (c) any combination of items in the list. Furthermore, as used herein, the phrase “and / or” in “A and / or B” means only A, only B, and both A and B. Furthermore, the terms “comprising,” “including,” “having,” and “with” are used throughout the text to mean at least one or more of the described features, such that any larger number of identical features and / or other features of additional types are not excluded.

[0138] Based on the foregoing, it should also be understood that various modifications can be made without departing from this disclosure or the technology of the present invention. For example, those skilled in the art will understand that the various components of the present invention can be further divided into sub-components, or the various components and functions of the present invention can be combined and integrated. Furthermore, certain aspects of the technology described in the context of a particular embodiment may be combined or eliminated in other embodiments. Moreover, although advantages associated with certain embodiments of the present invention have been described in the context of those embodiments, other embodiments may also exhibit these advantages, and not all embodiments necessarily exhibit these advantages to fall within the scope of the present invention. Therefore, this disclosure and associated technology may cover other embodiments not explicitly shown or described herein.

Claims

1. A method for bonding semiconductor dies, the method comprising: depositing a first dielectric on a first semiconductor die, wherein the first dielectric includes a first material and a second material at a first molecular ratio at a first surface of the first dielectric; depositing a second dielectric on a second semiconductor die, wherein the second dielectric includes the first material and the second material at a second molecular ratio different from the first molecular ratio at a second surface of the second dielectric; stacking the second semiconductor die and the first semiconductor die, wherein the first surface is in contact with the second surface; and bonding the first surface with the second surface by diffusing the second material from the second dielectric to the first dielectric.

2. The method of claim 1, wherein bonding the first surface with the second surface includes an exothermic reaction, and wherein the first molecular ratio and the second molecular ratio are stoichiometrically relatively imbalanced ratios.

3. The method of claim 1, wherein the first dielectric includes a third surface opposite the first surface in contact with the first semiconductor die, wherein the first dielectric includes the first material and the second material at a third molecular ratio different from the first molecular ratio at the third surface, and wherein the first dielectric includes a central portion having a gradient of molecular ratios from the third molecular ratio adjacent the third surface to the first molecular ratio adjacent the first surface.

4. The method of claim 1, wherein the first semiconductor die includes a first interconnect, wherein a portion of the first interconnect is at least partially exposed at the first surface; the second semiconductor die includes a second interconnect, wherein a portion of the second interconnect is exposed at the second surface; and the method further comprises: aligning the exposed portion of the first interconnect with the exposed portion of the second interconnect; and annealing the exposed portion of the first interconnect with the exposed portion of the second interconnect to form an electrical connection between the first interconnect and the second interconnect.

5. The method of claim 1, wherein bonding the first surface with the second surface includes heating the stacked first semiconductor die and second semiconductor die to initiate the diffusion.

6. The method of claim 1, wherein reacting the surface of the first dielectric with the second surface of the second dielectric includes providing an electrocatalyst to the stacked first semiconductor die and second semiconductor die to initiate the diffusion.

7. The method of claim 1, wherein depositing the first dielectric on the first semiconductor die includes a chemical vapor deposition process, and wherein a chemical vapor ratio is varied during the chemical vapor deposition process to deposit the first material and the second material at the first molecular ratio on the first surface. ​ 8. The method of claim 7, wherein the chemical vapor deposition process is a first chemical vapor deposition process, wherein the chemical vapor phase ratio is a first chemical vapor phase ratio, wherein depositing the second dielectric on the second semiconductor die includes a second chemical vapor deposition process, and wherein a second chemical vapor phase ratio is changed during the second chemical vapor deposition process opposite the first chemical vapor deposition process to deposit the first material and the second material in the second molecular ratio at the second surface.

9. The method of claim 1, wherein depositing the first dielectric on the first semiconductor die includes a spin-on process to deposit a spin-on dielectric, and wherein a material ratio is changed during the spin-on process to deposit the first material and the second material in the first molecular ratio at the first surface.

10. The method of claim 1, wherein: the first material is silicon, and the second material is oxygen; the first molecular ratio contains less oxygen than a stoichiometrically balanced silicon dioxide; the second molecular ratio contains more oxygen than the stoichiometrically balanced silicon dioxide; and the bonding causes oxygen to migrate from the second dielectric to the first dielectric.

11. A method for bonding a first semiconductor die to a second semiconductor die, the method comprising: depositing a first material on the first semiconductor die, wherein the first material has a first outer surface, and wherein the first material has a first chemical composition at the first outer surface; depositing a second material on the second semiconductor die, wherein the second material has a second outer surface, and wherein the second material has a second chemical composition at the second outer surface different from the first chemical composition; stacking the second outer surface of the second semiconductor die in contact with the first outer surface of the first semiconductor die; and reacting the first outer surface with the second outer surface, the reaction causing molecules from the first material to migrate to the second material to bond the first outer surface to the second outer surface.

12. The method of claim 11, wherein: the first semiconductor die includes a first interconnect having an exposed portion at the first outer surface and an embedded portion within the first semiconductor die; the second semiconductor die includes a second interconnect having an exposed portion at the second outer surface and a through-substrate portion within the second semiconductor die; and the method further comprises: aligning the exposed portion of the first interconnect with the exposed portion of the second interconnect prior to the reacting; and annealing the exposed portion of the first interconnect with the exposed portion of the second interconnect to form an electrical connection between the first interconnect and the second interconnect.

13. The method of claim 11, wherein: the first material and the second material comprise silicon-based dielectric materials; ​ ​ ​ The first chemical composition contains a higher silicon ratio compared to a stoichiometric balance of silicon of the dielectric material; and The second chemical composition contains a lower silicon ratio compared to the stoichiometric balance of silicon of the dielectric material.

14. The method of claim 11, wherein: The first material comprises a first polymeric backing gel having first molecular species suspended therein; and The second material comprises a second polymeric backing gel having second molecular species suspended therein, wherein the first and second molecular species are exothermically reactive, and wherein the reaction produces a third polymeric backing gel having third molecular species suspended therein.

15. The method of claim 11, wherein: The first material comprises a partially cured polymer having a first crosslinker concentration; and The second material comprises the partially cured polymer having a second crosslinker concentration higher than the first crosslinker concentration.

16. The method of claim 11, wherein after the reaction, the first outer surface of the first material and the second outer surface of the second material have a third chemical composition, wherein the third chemical composition is non-reactive with the first and second chemical compositions.

17. A stacked semiconductor device comprising: a first semiconductor die; a second semiconductor die disposed above the first semiconductor die; and a bonding layer positioned between the first semiconductor die and the second semiconductor die, the bonding layer comprising: a first portion between the first semiconductor die and the second semiconductor die having a first molecular composition; and a second portion between the first portion and the first semiconductor die having a second molecular composition different from the first molecular composition, wherein the bonding layer is a silicon dioxide dielectric, wherein the first molecular composition contains a molecular balance of silicon to oxygen, and wherein the second molecular composition contains less oxygen compared to the molecular balance of silicon to oxygen.

18. The stacked semiconductor device of claim 17, wherein: the bonding layer is a polymeric backing gel layer; the second portion of the bonding layer has first molecular species suspended therein; the bonding layer further comprises a third portion between the first portion and the second semiconductor die having second molecular species suspended therein; and the first portion of the bonding layer has third molecular species suspended therein, the third molecular species being a product of a reaction between the first and second molecular species.

19. A stacked semiconductor device comprising: a first semiconductor die; a second semiconductor die disposed above the first semiconductor die; and a bonding layer positioned between the first semiconductor die and the second semiconductor die, the bonding layer comprising: a first portion between the first semiconductor die and the second semiconductor die having a first molecular composition; and a second portion between the first portion and the first semiconductor die having a second molecular composition different from the first molecular composition, wherein the bonding layer is a silicon dioxide dielectric, wherein the first molecular composition contains a molecular balance of silicon to oxygen, and wherein the second molecular composition contains less oxygen compared to the molecular balance of silicon to oxygen. a second portion, between the first portion and the first semiconductor die, having a second molecular composition different from the first molecular composition, wherein: the bonding layer is a polymer substrate having a cross-linker; the first portion of the bonding layer has a first concentration of the cross-linker; and the second portion of the bonding layer has a second concentration of the cross-linker different from the first concentration.

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