3D multiple location compressing bonded arm for advanced integration

Abstract

This disclosed embodiment provides a bonding apparatus for bonding two wafers. For example, the bonding apparatus may include a first bonding chuck and a second bonding chuck. The first bonding chuck may have a first bonding head for mounting a first wafer thereon. The second bonding chuck may have a plurality of second bonding heads for mounting a second wafer thereon. The plurality of second bonding heads may be individually controlled to apply localized pressure to the second wafer to move the second wafer toward the first wafer to bond the second wafer to the first wafer, the localized pressure corresponding to measurement values ​​of the first and second wafers.

Description

3D Multi-Position Compression Bonding ARM for Advanced Integration This patent application claims priority to U.S. Non-Temporary Patent Application No. 18 / 081,207, filed on December 14, 2022, the entire content of which is incorporated herein by reference. This case relates to semiconductor manufacturing, and more particularly, to wafer bow, wafer-to-wafer bonding, and wafer-to-die bonding. The prior art sections provided herein are for the purpose of broadly interpreting the background of this disclosure. The works of the named inventors of this case, within the scope described in this prior art section, and the embodiments described that may not be eligible as prior art at the time of filing, are neither publicly nor implicitly admitted as prior art relative to this disclosure. Semiconductor manufacturing involves a variety of different steps and processes. A typical manufacturing process is called photolithography (also known as microlithography). Photolithography uses radiation, such as ultraviolet or visible light, to create fine patterns in semiconductor device designs. Many types of semiconductor devices, such as diodes, transistors, and integrated circuits, can be constructed using semiconductor manufacturing techniques including photolithography, etching, film deposition, surface cleaning, metallization, etc. An exposure system (also known as a tool) is used to implement photolithography technology. An exposure system typically includes an illumination system, a reticle (also known as a photomask) or spatial light modulator (SLM) for generating a circuit pattern, a projection system, and a wafer alignment platform for aligning the semiconductor wafer covered with a light-sensitive resist. The illumination system illuminates an area of the reticle or SLM with a (preferably) rectangular slot illumination field. The projection system projects an image of an illuminated area of the reticle pattern onto the wafer. For accurate projection, it is important to expose a light pattern onto a relatively flat or planar wafer, preferably having a height deviation of less than 10 micrometers. Bonding of two or more semiconductor wafers and / or dies provides higher performance for high-density semiconductor devices. Embodiments of this disclosure provide a system for bonding two wafers. For example, the system can include a bow measurement device, a bonding device, and a controller. The bow measurement device can be configured to measure a first wafer and a second wafer to identify bow measurement values of the first wafer and the second wafer. The bonding device can be configured to bond the first wafer to the second wafer. The controller can be coupled to the bow measurement device and the bonding device and configured to control the bonding device to apply stress to the first wafer and the second wafer based on the bow measurement values to bond the first wafer to the second wafer. In one embodiment, the second wafer is a die. In one embodiment, the system may further include a film forming device coupled to the controller, the film forming device configured to form an adhesive film on the first surfaces of the first wafer and the second wafer. For example, the system may further include a heat generator coupled to the controller, the heat generator configured to generate a heat pattern, wherein the film forming device is further configured to form first and second stress adjustment films on the second surfaces of the first wafer and the second wafer respectively, the first and second stress adjustment films being reactive to heat such that the applied heat adjusts the internal stress of the first and second stress adjustment films, the bow measurement device being further configured to measure the first wafer and the second wafer having the first and second stress adjustment films on their second surfaces respectively and adjust the internal stress of the first and second stress adjustment films to identify the bow measurement values of the first wafer and the second wafer, the bow measurement device being further configured to measure the first wafer and the second wafer having no stress adjustment film formed on their second surfaces to identify another bow measurement value of the first wafer and the second wafer, and the controller being further configured to control the heat generator to generate and apply the heat pattern to the first and second stress adjustment films, the heat pattern corresponding to the another bow measurement value. In another example, the system may further include a light generator coupled to the controller, the light generator configured to generate patterns of light of first and second wavelengths, wherein the film forming device is further configured to form first and second stress adjustment films on the second surfaces of the first wafer and the second wafer respectively, the first and second stress adjustment films being reactive to light of the first and second wavelengths respectively such that exposure to light of the first and second wavelengths adjusts the internal stress of the first and second stress adjustment films respectively, the bow measurement device being further configured to measure the first wafer and the second wafer having the first and second stress adjustment films formed on their second surfaces respectively and adjust the internal stress of the first and second stress adjustment films to identify the bow measurement values of the first wafer and the second wafer, the bow measurement device being further configured to measure the first wafer and the second wafer having no stress adjustment film formed on their second surfaces to identify another bow measurement value of the first wafer and the second wafer, and the controller being further configured to control the light generator to generate and apply patterns of light of first and second wavelengths to the first and second stress adjustment films respectively, the patterns of light of first and second wavelengths corresponding to the another bow measurement value. Embodiments of this disclosure provide a method for bonding two wafers. For example, the method may include: receiving a first wafer and a second wafer; measuring the first wafer and the second wafer to identify bow measurement values of the first wafer and the second wafer; and applying stress to the second surfaces of the first wafer and the second wafer based on the bow measurement values of the first wafer and the second wafer to bond the first wafer to the second wafer. In one embodiment, the method may further include forming an adhesive film on a first surface of the first wafer. For example, the method may further include measuring the first wafer having no stress adjustment film on its second surface to identify another bow measurement value of the first wafer; forming a stress adjustment film on the second surface of the first wafer, the stress adjustment film being responsive to heat such that applied heat adjusts the internal stress of the stress adjustment film; and applying a heat pattern to the stress adjustment film to adjust the internal stress of the stress adjustment film, the heat pattern corresponding to the another bow measurement value, wherein measuring the first wafer and the second wafer to identify the bow measurement values of the first wafer and the second wafer includes measuring the first wafer and the second wafer having the stress adjustment film formed on the second surface of the first wafer and adjusting the internal stress of the stress adjustment film to identify the bow measurement values of the first wafer and the second wafer. In another embodiment, the method may further include measuring the first wafer having no stress adjustment film formed on its second surface to identify another bow measurement value of the first wafer; forming a stress adjustment film on the second surface of the first wafer, the stress adjustment film being responsive to light of a wavelength, exposure to the light of the wavelength adjusting the internal stress of the stress adjustment film; and applying a pattern of the light of the wavelength to the stress adjustment film to adjust the internal stress of the stress adjustment film, the pattern of the light of the wavelength corresponding to the another bow measurement value, wherein measuring the first wafer and the second wafer to identify the bow measurement values of the first wafer and the second wafer includes measuring the first wafer and the second wafer having the stress adjustment film formed on the second surface of the first wafer and adjusting the internal stress of the stress adjustment film to identify the bow measurement values of the first wafer and the second wafer. In one embodiment, the method may further include measuring another die to identify another bow measurement value of the another die and applying additional stress to a first surface of the another die based on the another bow measurement value to bond the another die to the die. In another embodiment, the method may further include measuring another die to identify another bow measurement value of the another die and applying additional stress to a first surface of the another die based on the another bow measurement value to bond the another die to the second wafer. Embodiments of this disclosure provide an adhesive apparatus for bonding two wafers. For example, the adhesive apparatus may include a first adhesive chuck and a second adhesive chuck. The first adhesive chuck may have a first adhesive head for holding a first wafer mounted thereon. The second adhesive chuck may have a plurality of second adhesive heads for holding a second wafer mounted thereon. The plurality of second adhesive heads may be configured to be individually controlled to apply local stresses to the second wafer to move the second wafer toward the first wafer to bond the second wafer to the first wafer, the local stresses corresponding to bow measurement values of the first wafer and the second wafer. In one embodiment, the first bonding head can apply an overall stress to the first wafer to move the first wafer toward the second wafer to bond the first wafer to the second wafer. In another embodiment, the first bonding chuck can further include one or more heating units disposed in the first bonding head, the heating units configured to provide heat to cure an adhesive film for bonding the first wafer to the second wafer. In one embodiment, the second wafer can be a die, and the plurality of second bonding heads can be arranged in a configuration corresponding to the size of the die. In another embodiment, the first of the plurality of second bonding heads can be in a first shape, and the second of the plurality of second bonding heads can be in a second shape different from the first shape. For example, the first shape can be circular, rectangular, or crescent-shaped. It should be noted that the sections of the present invention content do not specify every embodiment and / or progressive novel implementation aspect of the invention disclosed or claimed herein. Instead, the present invention content only provides a preliminary discussion of different embodiments and novel points relative to the prior art. For additional details and / or possible perspectives regarding the present invention and its embodiments, the reader is directed to the embodiments section and the corresponding drawings of this disclosure, as further discussed below. To achieve optimal resolution, using a mask with a lithographic photosensitive agent sensitive to laser or EMS λ (electromagnetic spectrum wavelength) to define blocked or open areas for subsequent pattern transfer or implantation requires an optimized wafer surface shape prior to photolithography / lithography processing. The techniques disclosed herein include modulating film stress on a wafer to achieve a target curvature or correction. The techniques herein can be used with all types of photosensitive wavelengths / lithography types in the electromagnetic spectrum (some examples are photolithography, electron beam lithography, direct laser writing, and x-ray lithography). The techniques disclosed herein also include applying local stress to two wafers based on bow measurements of the two wafers to bond the two wafers to each other such that the thus-bonded two wafers have an optimized wafer shape. The techniques disclosed herein define several processing flows to achieve an optimized starting wafer shape (using semiconductor stress film tuning, or tuning its lattice) prior to light processing on the working surface of the wafer. The processing flows herein include a disposable stress tuning film on the backside surface of a wafer as an option. Another option is to leave the stress tuning film in place for subsequent processing for use in certain cases where low-temperature processing can be used for some steps. Another option for stress tuning is to use a lithography film that can be patterned using a mask or direct write, which can generate or adjust the internal stress in the lithography film. The unique implementation here is that the deposited lithography film can be compressive, tensile, or neutrally stressed, acting as a lithography photosensitizer sensitive to specific laser or EM wavelengths during deposition. Thus, micro-stress regions can be defined by etching the mask and the deposited film, or by direct write regions (or direct write options) that desire selective compressive / neutral / tensile regions. This process can also be repeated using two different depositions (i.e., one sensitive to the first laser wavelength and the other to the second laser wavelength) to eliminate wafer bowing after laser processing. The technology here includes wafer stress adjustment technology to adjust wafer bow and curvature to improve wafer overlay. Stress film deposition can be performed with options of depositing upward or downward on the wafer surface, for all processing flows of all options with clamped wafers. The technology here also includes bonding two wafers by applying local stress based on the bow measurement values of the two wafers. The microfabrication of semiconductor structure 100 starts with a flat substrate or wafer 110, such as those shown in FIGS. 1A to 1C. During the microfabrication of the semiconductor structure 100, multiple processing steps are performed, which may include: depositing materials on the wafer 110, removing materials, implanting dopants, annealing, baking, and so on. The different material and structural configurations 120 thus formed can cause internal stress in the wafer 110, resulting in bowing of the semiconductor structure 100, which in turn affects overlay and generally leads to overlay errors of different magnitudes. For example, FIGS. 1A and 1B show how the different material and structural configurations 120 can respectively induce compressive and tensile stresses in the wafer 110, causing first-order bowing, where the bow measurement value represents the height deviation in the z direction from a reference plane (not shown). As another example, FIG. 1C shows the second-order bowing of the wafer 110, where two bow measurement values respectively identify positive and negative height deviations in the z direction. If some regions of two bonded wafers 110 contain compressive stress or tensile stress, multiple stress heads can be used to allow local stress to generate a more efficient bonding process, and thus improve the die yield with an optimized wafer shape. Opposite types of stress can be applied in each local nano-stress region. By adjusting the internal stress of the stress adjustment film using an array of thermal / optical regions or positions on a wafer chuck, the optimized wafer shape can be achieved quickly and at the lowest cost. FIG. 2 is a functional block diagram of an exemplary system 200 for bonding two or more wafers and / or chips according to some embodiments of this disclosure. For example, the system 200 may include metrology equipment, such as a bow metrology device 210, configured to measure a substrate, a chip, or a wafer (e.g., the wafer 110 shown in FIGS. 1A - 1C) to identify the bow metrology value of the wafer 110. In one embodiment, the bow metrology device 210 may use light (e.g., using a scanning laser technique), sound, and other mechanisms to measure the z - direction height deviation of a surface of the entire wafer 110 and store the height deviation with (x, y) coordinates to identify a plurality of sub - bow metrology values (x, y) of the bow metrology value. The z - direction height deviation may be mapped at various different resolutions depending on the type of metrology equipment used and / or the desired resolution. The bow metrology value (and sub - bow metrology values) may include raw bow data or represent bow - up features with relative values. As shown in FIG. 1A, in one embodiment, the wafer 110 has a working surface 110A on which the different material and structural configurations 120 may be formed, and a back - side surface 110B opposite to the working surface 110A, as shown in FIG. 1. The wafer 110 may have a wafer bow - up amount that results from at least some of the one or more micro - manufacturing process steps that have been performed to produce a semiconductor structure (e.g., the semiconductor structure 100) on the working surface 110A of the wafer 110. For example, the transistor gates may be complete or only partially complete. The system 200 may further include a deposition module, such as a film - forming device 220, configured to deposit and form a film, such as a stress - adjusting film and a bonding film, on the back - side surfaces 110B and / or the working surfaces 110A of the wafers 110 and / or chips. For example, the film - forming device 220 may deposit the stress - adjusting film and the bonding film on the back - side surface 110B and the working surface 110A of the wafer 110, respectively, by spin - coating, laminating, spraying, or other suitable deposition techniques. When exposed to heat / light and being reactive to them, the internal stress of the stress - adjusting film can be adjusted by heat / light. The film - forming device 220 may be configured to form two or more stress - adjusting films with different (e.g., opposite) stresses. The bonding film may bond the wafers and chips to each other. The system 200 may further include a heat / light generator 230 configured to generate a heat / light pattern 300, as shown in FIG. 3. In one embodiment, the heat / light generator 230 may generate a laser (e.g., direct laser writing) and light of a plurality of wavelengths. In another embodiment, the heat / light generator 230 may include a plurality of heating / illuminating units that may be mounted on a wafer chuck and have a configuration corresponding to the heat / light pattern 300. For example, the heat / light generator 230 may include heating / illuminating units (3, 1) to (6, 1), (2, 2) to (7, 2), (1, 3) to (8, 3), (1, 4) to (8, 4), (1, 5) to (8, 5), (1, 6) to (8, 6), (2, 7) to (7, 7), and (3, 8) to (6, 8), a total of 52 heating / illuminating units, and the bow measurement device 210 may measure the wafer 110 to identify the bow measurement value of the wafer 110, which includes corresponding sub-bow measurement values (3, 1) to (6, 1), (2, 2) to (7, 2), (1, 3) to (8, 3), (1, 4) to (8, 4), (1, 5) to (8, 5), (1, 6) to (8, 6), (2, 7) to (7, 7), and (3, 8) to (6, 8). The heat / light (Poseidon) micro-pattern 300 herein may eliminate warping, such that high-resolution lithographic patterning may be maintained in all processing steps for 3D stacking. The heat / light generator (or heat generator) 230 may generate heat in a plurality of temperature ranges. For example, the heat generator 230 may generate heat in a first temperature range up to 200°C, heat in a second temperature range between 200°C and 500°C, heat in a third temperature range between 500°C and 800°C, and heat in a fourth temperature range above 800°C. Referring back to FIG. 2, the system 200 may further include a bonding device 240 configured to apply pressure to two wafers and / or dies, at least one of whose surfaces (e.g., the working surface) has a bonding film formed thereon, to bond the two wafers and / or dies to each other. The system 200 may further include a controller 250, which is coupled to the bow measurement device 210, the film forming device 220, the heat / light generator 230, and the bonding device 240. The controller 250 may be configured to control the bow measurement device 210 to measure the wafers (and / or dies) 110 to identify the bow measurement values (and sub-bow measurement values) of the wafers 110, control the film forming device 220 to form the stress adjustment film and / or the bonding film on the back surfaces 110B and / or the working surfaces 110A of the wafers 110, control the heat / light generator 230 to generate and apply the heat / light pattern 300 to the stress adjustment film, the heat / light pattern corresponding to the bow measurement values (and the sub-bow measurement values), and control the bonding device 240 to bond the two wafers 110 to each other. The controller 250 may be a computer processor located in the system 200, or a computer processor located remotely but communicating with the components of the system 200. The system 200 may further include other components, such as: a wafer chuck for placing a wafer thereon; a robotic manipulator configured to flip the wafer 110 and transport the wafers between various different devices and / or chambers; a wafer gripper configured to grip the wafer 110; a coating device configured to coat the back surface 110B of the wafer 110 with a radiation-sensitive material such as photoresist; a baking device configured to bake the photoresist; an imaging device configured to expose the photoresist to a pattern of actinic radiation; a developing device configured to develop a latent image in the photoresist; and an etching device configured to use plasma or vapor etching or wet etching. FIG. 4 is a schematic diagram of an exemplary bonding device 400 (e.g., the bonding device 240 of the system 200) according to some embodiments of this disclosure. In one embodiment, the bonding device 400 may include a bottom (or first) bonding chuck 410 and a top (or second) bonding chuck 420, which are controlled by a controller (e.g., the controller 250) to move towards or away from each other and apply pressure to a first wafer 430 and a second wafer 440 (e.g., the wafer 110), at least one of which has a bonding film 450 formed on one of its surfaces (e.g., the working surface 110A), to bond the first wafer 430 to the second wafer 440 to each other. In one embodiment, the bonding film 450 may be insulating and include epoxy resin, metal, or a combination thereof. In one embodiment, the bottom bonding chuck 410 may include a bottom bonding (or pressure) head 411, such as circular, for mounting the first wafer 430 thereon. The bottom bonding head 411 may apply a global pressure (i.e., force / first wafer area) to the first wafer 430. The bottom bonding chuck 410 may further include one or more holes or perforations (not shown) formed in its mounting surface 410A. A vacuum system may be coupled to the bottom bonding chuck 410 and transmit negative pressure through the holes or perforations to the first wafer 430 to hold the first wafer 430 in place during subsequent bonding steps. In one embodiment, the top bonding chuck 420 may include a plurality of top bonding (or pressure) heads 421 for mounting the second wafer 440 thereon. For example, the plurality of top bonding heads 421 may be arranged corresponding to the layout of the heat / light pattern 300 and individually controlled by the controller 250 based on the bow measurement values of the second wafer 440 to apply local pressure to the second wafer 440. The top bonding chuck 420 may also include one or more holes or perforations (not shown) formed in its mounting surface 420A. A vacuum system may be coupled to the top bonding chuck 420 and transmit negative pressure through the holes or perforations to the second wafer 440 to hold the second wafer 440 in place during subsequent bonding processes. The plurality of top bonding heads 421 may be of various different shapes. For example, a bonding device 500 may include: a first group 521A of rectangular (e.g., square) plurality of top bonding heads 421, a second group 521B of circular plurality of top bonding heads 421, and a third group 521C of crescent-shaped plurality of top bonding heads 421, as shown in FIG. 5. In some embodiments, the heat / light generator 230 may include one or more groups of heating / lighting units having different shapes. FIG. 6 shows a flowchart of an exemplary method (or process flow) 600 according to some embodiments of this disclosure, the exemplary method 600 using a bonding device to bond two wafers. In different embodiments, some steps of the shown method 600 may be performed in parallel or in a different order than shown, may be replaced by other method steps, or may be omitted. Additional method steps may also be performed as desired. Embodiments of the method 600 may be implemented using a system, such as the system 200 depicted and described in the previous figures. In step S610, the curvatures / bows of the first and second wafers 430 and 440 to be bonded to each other are measured. For example, the bow measurement device 210 may be used to measure the first wafer 430 and the second wafer 440 to identify the bow measurement values of the first wafer 430 and the second wafer 440. In step S620, optionally, a stress adjustment film 610 may be formed on the backside surfaces of the first wafer 430 and the second wafer 440 and exposed to heat / light to adjust the internal stress of the stress adjustment film 610 by heat / light to adjust the curvature / camber of the first wafer 430 and the second wafer 440. For example, the film forming device 220 may be used to deposit and form the stress adjustment film 610 on the backside surfaces of the first wafer 430 and the second wafer 440, and the heat / light generator 230 may be used to generate a heat / light pattern based on the camber measurement values of the first wafer 430 and the second wafer 440 to adjust the internal stress of the stress adjustment film 610. The method 600 may then return to step S610 to measure the curvature / camber of the first wafer 430 and the second wafer 440 with the stress adjustment film 610 formed on their backside surfaces. In step 630, which is after step S610 or step S620, an adhesive film (such as adhesive film 450) may be formed on the working surface of at least one of the first wafer 430 and the second wafer 440. In an exemplary embodiment, a first adhesive film 651 and a second adhesive film 652 may be respectively formed on the working surfaces of the first wafer 430 and the second wafer 440. For example, the film forming device 220 may be used to sequentially deposit and form the first adhesive film 651 on the working surface of the first wafer 430 and the second adhesive film 652 on the working surface of the second wafer 440. In step S640, the first wafer 430 having the first adhesive film 651 formed on its working surface is mounted onto the bottom bonding head 411 of the bottom bonding chuck 410. The vacuum system may then be turned on to transmit negative pressure through the holes or perforations in the mounting surface 410A (shown in FIG. 4) to the first wafer 430 to hold the first wafer 430 in place during subsequent bonding processes. In step S650, the second wafer 440 having the second adhesive film 652 formed on its working surface is mounted onto the plurality of top bonding heads 421 of the top bonding chuck 420. The vacuum system may transmit negative pressure through the holes or perforations in the mounting surface 420A (shown in FIG. 4) to the second wafer 440 to hold the second wafer 440 in place during subsequent bonding processes. In an embodiment, steps S640 and S650 may be performed in a different order. In step S660, the first wafer 430 and the second wafer 440 are bonded to each other. For example, the controller 250 can control the bottom bonding chuck 410 and the top bonding chuck 420 to align and move towards each other until the first bonding film 651 contacts the second bonding film 652, and control the bottom bonding head 411 to apply a global pressure to the first wafer 430, and control the plurality of top bonding heads 421 to apply a local pressure to the second wafer 440 based on the bow measurement value of the second wafer 440, so as to bond the second bonding film 652 to the first bonding film 651, and thus bond the second wafer 440 to the first wafer 430. In an embodiment, the bonding technique for the first bonding film 651 and the second bonding film 652 may include direct bonding, anodic bonding, gluing, welding bonding, eutectic bonding, etc. In step S670, the bonded first wafer 430 and second wafer 440 are removed from the bottom bonding chuck 410 and the second bonding chuck 420 respectively for subsequent operation options, such as: dicing into chips. For example, the vacuum system can be turned off and the bonded first wafer 430 and second wafer 440 can be released from the holding of the bottom bonding chuck 410 and the second bonding chuck 420 respectively. Thus, the bonded first wafer 430 and second wafer 440 have an optimized wafer shape. FIG. 7 is a schematic diagram of an exemplary bonding device 700 (e.g., the bonding device 240 of the system 200) according to some embodiments of this disclosure. The bonding device 700 may include the top bonding chuck 420 and a bottom bonding chuck 710. Compared with the bottom bonding chuck 410 of the bonding device 400 shown in FIG. 4, the bottom bonding chuck 710 of the bonding device 700 further includes one or more heating units 721, which are disposed in the bottom bonding head 411 and controlled by the controller 250 to provide heat to harden the bonding film 450. FIG. 8 shows a flowchart of an exemplary method (or process) 800 according to some embodiments of this disclosure. The exemplary method 800 uses an adhesive device (e.g., the adhesive device 700) to bond two wafers. Embodiments of the method 800 can be implemented using a system, such as the system 200 depicted and described in the previous figures. The method 800 may also include steps S610 - S650 and S670 of the method 600. In one embodiment, the method may further include step S760, which is performed between steps S650 and S670. In step S760, the first wafer 430 and the second wafer 440 are bonded to each other. For example, the controller 250 can control the bottom bonding chuck 710 and the top bonding chuck 420 to align and move towards each other until the first bonding film 651 and the second bonding film 652 come into contact, and control the bottom bonding head 411 to apply global pressure to the first wafer 430, and control the plurality of top bonding heads 421 to apply local pressure to the second wafer 440 based on the bow measurement value of the second wafer 440, and control the heating units 721 to provide heat to harden the first bonding film 651 and the second bonding film 652, to bond the second bonding film 652 to the first bonding film 651, and thus bond the second wafer 440 to the first wafer 430. FIG. 9 shows a flowchart of an exemplary method (or process) 900 according to some embodiments of this disclosure. The exemplary method 900 uses an adhesive device to bond a plurality of chips to a wafer. Embodiments of the method 900 can be implemented using a system, such as the system 200 depicted and described in the previous figures. The method 900 is different from the method 800 in that in the method 900, a top bonding chuck 920 and a plurality of chips 940 replace the top bonding chuck 420 and the second wafer 440 used in the method 800 shown in FIG. 8. In step S910, the curvature / bow of the first wafer 430 and the chips 940 to be bonded to each other is measured. For example, the bow measurement device 210 can be used to measure each of the first wafer 430 and the chips 940 to identify the bow measurement values of the first wafer 430 and the chips 940. In step S920, optionally, the stress adjustment film 610 and a stress adjustment film 910 may be formed on the backside surfaces of the first wafer 430 and the chips 940 and exposed to heat / light to adjust the internal stress of the stress adjustment film 610 and the stress adjustment film 910 by using heat / light, so as to adjust the curvature / bow of the first wafer 430 and the chips 940. For example, the film forming device 220 may be used to deposit and form the stress adjustment films 610 and 910 on the backside surfaces of the first wafer 430 and the chips 940 respectively, and the heat / light generator 230 may be used to generate a heat / light pattern based on the bow measurement value of each of the first wafer 430 and the chips 940 to adjust the internal stress of the stress adjustment films 610 and 910. The method 900 may then return to step S910 to measure the curvature / bow of the first wafer 430 and the chips 940 with the stress adjustment films 610 and 910 formed on their backside surfaces. In step S930, after step S910 or step S920, an adhesive film, such as the adhesive film 450, may be formed on the working surfaces of the first wafer 430 and / or the chips 940. In an exemplary embodiment, a first adhesive film 651 and a second adhesive film 952 may be formed on the working surfaces of the first wafer 430 and the chips 940 respectively. For example, the film forming device 220 may be used to sequentially deposit and form the first adhesive film 651 on the working surface of the first wafer 430 and the second adhesive film 952 on the working surfaces of the chips 940. In step S940, the first wafer 430 with the first adhesive film 651 formed on its working surface is mounted onto the bottom adhesive head 411 of the bottom adhesive chuck 710 (or the bottom adhesive chuck 410). The vacuum system may then be turned on to transmit negative pressure through the holes or perforations in the mounting surface 410A (shown in FIG. 4) to the first wafer 430 to hold the first wafer 430 in place during subsequent bonding processes. In step S950, the chips 940 each having the second bonding film 952 formed on its working surface are mounted one by one onto the top bonding head 921 of a top bonding chuck 920. In some embodiments, for example, the top bonding heads 921 may be arranged corresponding to the configuration of the thermal / optical pattern 300 and are individually controlled by the controller 250 based on the bow measurement values of the chips 940. The top bonding chuck 920 may also include one or more holes or perforations (not shown) formed in its mounting surface 920A. A vacuum system may be coupled to the top bonding chuck 920 and transmit negative pressure through the holes or perforations to each of the chips 940 to hold the chips 940 in place during subsequent bonding processes. The top bonding heads 921 may be of various different shapes. In step S950, the vacuum system may be turned on and transmit negative pressure through the holes or perforations in the mounting surface 920A to the chips 940 to hold the chips 940 in place during subsequent bonding processes. In one embodiment, steps S940 and S950 may be performed in a different order. In step S960, the first wafer 430 and one of the chips 940 are bonded to each other. For example, the controller 250 may control the bottom bonding chuck 410 and the top bonding chuck 920 to align and move towards each other until the first bonding film 651 contacts the second bonding film 952, and control the bottom bonding head 411 to apply global pressure to the first wafer 430 and the top bonding heads 921, and apply local pressure to the chip 940 based on the bow measurement value of the chip 940 to bond the second bonding film 952 to the first bonding film 651, and thereby bond the chip 940 to the first wafer 430. In step S970, the chips 940 are removed from the top bonding chuck 920 for subsequent processing options, such as: bonding other chips. For example, the vacuum system may be turned off and the last one of the chips 940 may be released from the hold of the top bonding chuck 920. Thus, the first wafer 430 bonded with the chips 940 has an optimized wafer / chip shape. In step S971, the portion of the first bonding film 651 that is not bonded to the second bonding film 952 may be subjected to etching and removal, and replaced with a dielectric layer 960 that separates and insulates the chips 940 from each other. In step S972, the curvature / camber of each of the additional plurality of chips 930 to be bonded to the chips 940 is measured. The first bonding film 951 and the second bonding film 932 are respectively formed on the back surfaces of the chips 940 and the other chips 930. The other chips 930 are mounted on the top bonding heads 921 of the top bonding chuck 920, and the top bonding chuck 920 and the bottom bonding chuck 410 are controlled to align and move towards each other to bond the first bonding film 951 to the second bonding film 932. In step S973, the chips 940 and the other chips 930 are bonded to each other. For example, the controller 250 can control the bottom bonding chuck 410 and the top bonding chuck 920 to align and move towards each other until the first bonding film 951 contacts the second bonding film 932, and control the bottom bonding heads 411 to apply a global pressure to the chips 940 and the top bonding heads 921, and apply a local pressure to the other chips 930 based on the camber measurement values of the other chips 930, so as to bond the second bonding film 932 to the first bonding film 951 and thus bond the chips 940 to the other chips 930. In the foregoing description, specific details of the description of a particular geometry such as a processing system and different components and processes used therein are set forth. However, it is understood that the techniques herein may be practiced in other embodiments different from these specific details, and such details are for explanatory rather than limiting purposes. The embodiments disclosed herein have been described with reference to the accompanying drawings. Similarly, for purposes of explanation, specific numbers, materials, and configurations have been set forth to provide a complete understanding. Nevertheless, the embodiments may be practiced without such specific details. Components having substantially the same functional construction are denoted by like characters, and thus any redundant description may be omitted. Of course, the order of discussion of the different steps as described herein is presented for clarity. Generally, these steps may be performed in any suitable order. In addition, although each of the different features, techniques, configurations, etc. herein may be discussed separately in this disclosure, it is intended that each concept can be implemented independently of each other or in combination with each other. Therefore, this disclosure can be embodied and understood in many different ways. The different techniques have been described with multiple discrete operations to assist in the understanding of the different embodiments. The order of description should not be construed to mean that these operations are necessarily sequentially related. Moreover, these operations do not need to be performed in the order presented. The operations described may be performed in a different order from the described embodiments. In additional embodiments, different additional operations may be performed and / or the operations described may be omitted. As used herein, the "substrate" or "target substrate" generally refers to an object that is processed according to this disclosure. The substrate can include any material part or structure of a device (especially a semiconductor or other electronic device), and can be, for example: a base substrate structure, such as a semiconductor wafer, a mask, or a layer (such as a thin film) on or covering a base substrate structure. Thus, the substrate is not limited to any particular base structure, underlying layer or overlying layer, patterned or unpatterned, but should be understood to include any such layer or base structure, and any combination of such layers and / or base structures. This description may refer to a particular kind of substrate, but this is for illustrative purposes only. Those skilled in the art will also understand that many variations can be made to the operation of the techniques explained above while still achieving the same objectives as this invention. Such variations are intended to be encompassed within the scope of this disclosure. Accordingly, the foregoing description of embodiments of the invention has no limiting significance. Instead, any limitations of embodiments of this invention are presented in the claims below. 100: Semiconductor structure 110: Wafer 110A: Working surface 110B: Backside surface 120: Different material and structural configurations 200: System 210: Bow measurement device 220: Film forming device 230: Heat / light generator (or heat generator) 240: Bonding device 250: Controller 300: Pattern 400: Bonding device 410: Bottom bonding chuck 410A: Mounting surface 411: Bottom bonding head 420: Top (second) bonding chuck 420A: Mounting surface 421: Top bonding head 430: First wafer 440: Second wafer 450: Bonding film 500: Bonding device 521A, 521B, 521C: Group 600: Method 610: Stress adjustment film 651: First bonding film 652: Second bonding film 700: Bonding device 710: Bottom bonding chuck 721: Heating unit 800, 900: Method 910: Stress adjustment film 920: Top bonding chuck 920A: Mounting surface 921: Top bonding head 930: Chip 932: Second bonding film 940: Chip 951: First bonding film 952: Second bonding film 960: Dielectric layer Various embodiments of this disclosure are described in detail by way of example with reference to the accompanying drawings, where the same numbers refer to the same elements, and where: Figures 1A to 1C show the first-order and second-order bowing of a wafer. Figure 2 is a functional block diagram of an example system according to some embodiments of this disclosure, the example system being used for bonding two wafers and / or chips. Figure 3 shows an example heat pattern generated by a heat generator of the example system shown in Figure 2. FIG. 4 is a schematic diagram of a first exemplary bonding device according to some embodiments of this disclosure. FIG. 5 shows the shape of the top bonding head of the bonding device of FIG. 4 according to some embodiments of this disclosure. FIG. 6 shows a flowchart of a first exemplary method (or process flow) of bonding two wafers using a bonding device according to some embodiments of this disclosure. FIG. 7 is a schematic diagram of a second exemplary bonding device according to some embodiments of this disclosure. FIG. 8 shows a flowchart of a second exemplary method (or process flow) of bonding two wafers using a bonding device according to some embodiments of this disclosure. FIG. 9 shows a flowchart of a third exemplary method (or process flow) of bonding two wafers using a bonding device according to some embodiments of this disclosure. 410: Bottom bonding chuck 411: Bottom bonding head 420: Top (second) bonding chuck 421: Top bonding head 430: First wafer 440: Second wafer 600: Method 610: Stress adjustment film 651: First bonding film 652: Second bonding film

Claims

1. A system for bonding two wafers, comprising: a measurement device configured to measure a first wafer and a second wafer to identify measurement values ​​of the first wafer and the second wafer; a bonding device configured to bond the first wafer to the second wafer; a controller coupled to the measurement device and the bonding device, the controller configured to control the bonding device to apply pressure to the first wafer and the second wafer based on the measurement values ​​to bond the first wafer to the second wafer; and a film deposition device coupled to the controller, the film deposition device configured to form an adhesive film on a first surface of the first wafer and the second wafer. The system further includes a heat generator coupled to the controller, the heat generator being configured to generate a thermal pattern. The film-forming apparatus is further configured to form first and second stress-adjusting films on the second surfaces of the first and second wafers, respectively. The first and second stress-adjusting films are heat-responsive, such that applied heat adjusts the internal stress of the first and second stress-adjusting films. A measurement device is further configured to measure the first and second wafers with the first and second stress-adjusting films respectively on their second surfaces, thereby adjusting their internal stress, to identify the measurement values ​​of the first and second wafers. The measurement device is also configured to measure the first and second wafers without any stress-adjusting films formed on their second surfaces, thereby identifying another measurement value of the first and second wafers. The controller is further configured to control the heat generator to generate and apply the thermal pattern to the first and second stress-adjusting films, the thermal pattern corresponding to the other measurement value. Alternatively, the system may further include a light generator coupled to the controller. The light generator is configured to generate patterns of light of first and second wavelengths. The film-forming apparatus is further configured to form first and second stress-adjusting films on the second surfaces of the first wafer and the second wafer, respectively. The first and second stress-adjusting films are responsive to the first and second wavelengths of light, respectively, so that the light exposed to the first and second wavelengths of light adjusts the internal stress of the first and second stress-adjusting films, respectively. The measurement device is further configured to measure the first wafer and the second wafer on which the first and second stress-adjusting films are formed on their second surfaces and whose internal stresses are adjusted, to identify the measurement value of the first wafer and the second wafer. The measurement device is further configured to measure the first wafer and the second wafer on which no stress-adjusting film is formed on their second surfaces, to identify another measurement value of the first wafer and the second wafer. The controller is further configured to control the light generator to generate and apply patterns of light of the first and second wavelengths to the first and second stress-adjusting films, respectively. The patterns of light of the first and second wavelengths correspond to the other measurement value.

2. The system of claim 1, wherein the second wafer is a chip.

3. A method for bonding two wafers, comprising: receiving a first wafer and a second wafer; measuring the first wafer and the second wafer to identify dimensional measurements of the first wafer and the second wafer; applying pressure to a second surface of the first wafer and the second wafer based on the dimensional measurements of the first wafer and the second wafer to bond the first wafer to the second wafer; and forming an adhesive film on a first surface of the first wafer. The method further includes measuring the first wafer on which no stress-adjusting film is formed on its second surface to identify another measurement value of the first wafer; forming a stress-adjusting film on the second surface of the first wafer, the stress-adjusting film being heat-responsive such that applied heat adjusts the internal stress of the stress-adjusting film; and applying a thermal pattern to the stress-adjusting film to adjust the internal stress of the stress-adjusting film, the thermal pattern corresponding to the other measurement value; wherein the step of measuring the first wafer and the second wafer to identify the measurement value of the first wafer and the second wafer includes measuring the first wafer and the second wafer on which the stress-adjusting film is formed on the second surface of the first wafer and its internal stress is adjusted, to identify the measurement value of the first wafer and the second wafer, or the method further includes... The method of measuring the first wafer and the second wafer to identify the measurement value of the first wafer includes measuring the first wafer and the second wafer on which the stress adjustment film is formed on the second surface of the first wafer, the stress adjustment film being reactive to a certain wavelength of light, the internal stress of the stress adjustment film being adjusted by exposure to the light of that wavelength, and applying a pattern of light of that wavelength to the stress adjustment film to adjust the internal stress of the stress adjustment film, the pattern of the light of that wavelength corresponding to the other measurement value.

4. The method of claim 3, wherein the first wafer is a chip.

5. The method of claim 4 further comprises: measuring another wafer to identify another measurement value of the other wafer; and applying additional pressure to a first surface of the other wafer based on the other measurement value to bond the other wafer to the wafer.

6. The method of claim 4 further comprises: measuring another wafer to identify another measurement value of the other wafer; and applying additional pressure to a first surface of the other wafer based on the other measurement value to bond the other wafer to the second wafer.

7. A bonding apparatus for bonding two wafers, comprising: a first bonding chuck having a first bonding head for mounting a first wafer thereon; and a second bonding chuck having a plurality of second bonding heads for mounting a second wafer thereon, the plurality of second bonding heads being individually controlled to apply local pressure to the second wafer to move the second wafer toward the first wafer, thereby bonding the second wafer to the first wafer, the local pressures corresponding to dimensional measurements of the first wafer and the second wafer, wherein the first bonding chuck further includes one or more heating units disposed in the first bonding head, the heating units being configured to provide heat to harden an adhesive film for bonding the first wafer to the second wafer, or the first of the plurality of second bonding heads having a first shape, and the second of the plurality of second bonding heads having a second shape different from the first shape.

8. The bonding apparatus of claim 7, wherein the first bonding head applies full-area pressure to the first wafer to move the first wafer toward the second wafer, thereby bonding the first wafer to the second wafer.

9. The bonding apparatus of claim 7, wherein the second wafer is a chip, and the plurality of second bonding heads are configured in a manner consistent with the size of the chip.

10. The adhesive device of claim 7, wherein the first shape is circular.

11. The adhesive device of claim 7, wherein the first shape is rectangular.

12. The adhesive device of claim 7, wherein the first shape is crescent-shaped.

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