3D multi-point compression joint arm for advanced integration

Abstract

Aspects of the present disclosure provide a bonding device for bonding two wafers. For example, the bonding device may include a first bonding chuck and a second bonding chuck. The first bonding chuck may have a first bonding head on which a first wafer is mounted. The second bonding chuck may have a plurality of second bonding heads on which the second wafers are mounted. The second bonding heads may be individually controlled to apply local pressure to the second wafer and move the second wafer toward the first wafer to bond the second wafer to the first wafer, the local pressure corresponding to warpage measurements of the first and second wafers.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Non-Provisional Patent Application No. 18 / 081,207, filed December 14, 2022, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to semiconductor manufacturing, and more particularly to wafer bow, wafer-to-wafer bonding, and wafer-to-die bonding. [Background technology]

[0003] The background description provided herein is intended to provide a general overview of the contents of the present disclosure, and the inventors' work to the extent described in this background section, and aspects of the description that would not otherwise qualify as prior art at the time of filing, are not admitted explicitly or implicitly as prior art to the present disclosure.

[0004] Semiconductor manufacturing involves several different steps and processes. One typical manufacturing process is known as photolithography (also called microlithography). Photolithography uses radiation, such as ultraviolet or visible light, to create fine patterns in semiconductor device designs. Various 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.

[0005] An exposure system (also called an exposure tool) is used to implement photolithography techniques. An exposure system typically includes an illumination system, a reticle (also called a photomask) or spatial light modulator (SLM) that creates the circuit pattern, a projection system, and a wafer alignment stage that aligns a semiconductor wafer covered with a photosensitive resist. The illumination system illuminates a region of the reticle or SLM with an illumination field (preferably a rectangular slot). The projection system projects an image of the illuminated region of the reticle pattern onto the wafer. For accurate projection, it is important to expose a relatively flat or planar wafer, preferably with a height deviation of less than 10 micrometers, to the light pattern. Bonding two or more semiconductor wafers and / or dies provides higher performance in high-density semiconductor devices. Summary of the Invention

[0006] Aspects of the present disclosure provide a system for bonding two wafers. For example, the system may include a warp measurement device, a bonding device, and a controller. The warp measurement device may be configured to measure a first wafer and a second wafer to determine warp measurements of the first wafer and the second wafer. The bonding device may be configured to bond the first wafer to the second wafer. The controller may be coupled to the warp measurement device and the bonding device and configured to control the bonding device to apply pressure to the first wafer and the second wafer to bond the first wafer to the second wafer based on the warp measurements. In one embodiment, the second wafer is a die.

[0007] In one embodiment, the system may further include a film forming device coupled to the controller, the film forming device configured to form a bonded film on the first surfaces of the first and second wafers. For example, the system may further include a heat generator coupled to the controller, the heat generator configured to generate a pattern of heat, the film forming device further configured to form first and second stress-modifying films on the second surfaces of the first and second wafers, respectively, the first and second stress-modifying films being heat-responsive, whereby the applied heat modifies internal stresses in the first and second stress-modifying films, and the warpage measurement device may measure the first and second wafers with the first and second stress-modifying films on their second surfaces, respectively. and measuring the first wafer and the second wafer in a state in which their internal stresses have been modified to determine a warpage measurement value of the first wafer and the second wafer, the warpage measurement device is further configured to measure the first wafer and the second wafer in a state in which no stress-modifying film has been formed on their second surfaces to determine another warpage measurement value of the first wafer and the second wafer, and the controller is further configured to control the heat generator to generate and apply a pattern of heat to the first and second stress-modifying films, the pattern of heat corresponding to another warpage measurement value.As another example, the system may further include a light generator coupled to the controller, the light generator configured to generate patterns of first and second wavelengths of light; the film forming device further configured to form first and second stress modifying films on the second surfaces of the first and second wafers, respectively, the first and second stress modifying films being responsive to the first and second wavelengths of light, respectively, whereby exposure to the first and second wavelengths of light modifies internal stresses in the first and second stress modifying films, respectively; and the warpage measurement device further configured to form the first and second stress modifying films on the second surfaces of the first and second wafers, respectively, whereby exposure to the first and second wavelengths of light modifies internal stresses in the first and second stress modifying films, respectively. The warpage measurement device is further configured to measure the first wafer and the second wafer with the positive film formed and its internal stress modified to determine a warpage measurement value of the first wafer and the second wafer, and the warpage measurement device is further configured to measure the first wafer and the second wafer without any stress-modifying film formed on their second surfaces to determine another warpage measurement value of the first wafer and the second wafer, and the controller is further configured to control the light generator to generate and apply patterns of first and second wavelengths of light to the first and second stress-modifying films, respectively, the patterns of the first and second wavelengths of light corresponding to another warpage measurement value.

[0008] Aspects of the present 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 determine warpage measurements of the first wafer and the second wafer, and applying pressure to second surfaces of the first wafer and the second wafer based on the warpage measurements of the first wafer and the second wafer to bond the first wafer to the second wafer.

[0009] In one embodiment, the method may further include forming a bonding film on the first surface of the first wafer. For example, the method may further include measuring the first wafer without any stress modifying film formed on its second surface to determine another warpage measurement of the first wafer, forming a stress modifying film on the second surface of the first wafer, the stress modifying film being heat responsive whereby the applied heat modifies internal stress of the stress modifying film, and applying a heat pattern to the stress modifying film to modify the internal stress of the stress modifying film, the heat pattern corresponding to the another warpage measurement, and the measuring the first and second wafers to determine the warpage measurement of the first and second wafers includes measuring the first and second wafers with the stress modifying film formed on the second surface of the first wafer and with the internal stress modified to determine the warpage measurement of the first and second wafers. As another embodiment, the method may further include measuring the first wafer without any stress modifying film formed on its second surface to determine another warpage measurement value for the first wafer; forming a stress modifying film on the second surface of the first wafer, the stress modifying film being sensitive to optical wavelengths such that exposure to the optical wavelengths modifies the internal stress of the stress modifying film; and applying a pattern of optical wavelengths to the stress modifying film to modify the internal stress of the stress modifying film, the pattern of optical wavelengths corresponding to another warpage measurement value, wherein measuring the first wafer and the second wafer to determine the warpage measurement value for the first wafer and the second wafer includes measuring the first wafer and the second wafer with the stress modifying film formed on the second surface of the first wafer and with the internal stress modified to determine the warpage measurement value for the first wafer and the second wafer.

[0010] In one embodiment, the method may further include measuring another die to determine another warpage measurement of the another die, and applying another pressure to a first surface of the another die based on the another warpage measurement to bond the another die to the die. In another embodiment, the method may further include measuring another die to determine another warpage measurement of the another die, and applying another pressure on a first surface of the another die based on the another warpage measurement to bond the another die to the second wafer.

[0011] Some aspects of the present disclosure provide a bonding device for bonding two wafers. For example, the bonding device may include a first bonding chuck and a second bonding chuck. The first bonding chuck may have a first bonding head on which the first wafer is mounted. The second bonding chuck may have a plurality of second bonding heads on which the second wafer is mounted. The second bonding heads may be configured to be individually controlled to apply local pressure to the second wafer to move the second wafer toward the first wafer and bond the second wafer to the first wafer, the local pressure corresponding to warpage measurements of the first and second wafers.

[0012] In one embodiment, the first bonding head can apply an overall pressure to the first wafer and 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 on the first bonding head, the heating units configured to provide heat to cure a bonding film used to bond the first wafer to the second wafer.

[0013] In one embodiment, the second wafer can be a die, and the second bond heads can be arranged in a configuration sized for the die. In another embodiment, a first one of the second bond heads can have a first shape, and a second one of the second bond heads can have a second shape that is different from the first shape. For example, the first shape can be a circle, a rectangle, or a crescent.

[0014] It should be noted that this Summary section does not specify every embodiment and / or inherently novel aspect of the present invention as set forth in this disclosure or claims. Instead, this Summary provides only a preliminary discussion of various embodiments and corresponding points of novelty over the prior art. For additional details and / or possible perspectives of the present disclosure and embodiments, the reader is referred to the Detailed Description section of the present disclosure and corresponding figures, further discussed below.

[0015] Various embodiments of the present disclosure, presented by way of example only, will now be described in detail with reference to the following figures, in which like reference numerals refer to like elements and in which: [Brief explanation of the drawings]

[0016] [Figure 1A] The primary and secondary warpage of the wafer is shown. [Figure 1B] The primary and secondary warpage of the wafer is shown. [Figure 1C] The primary and secondary warpage of the wafer is shown. [Figure 2] FIG. 1 is a functional block diagram of an exemplary system for bonding two wafers and / or dies, according to some embodiments of the present disclosure. [Figure 3] 3 illustrates an exemplary pattern of heat generated by a heat generator of the exemplary system shown in FIG. 2. [Figure 4] 1 is a schematic diagram of a first exemplary bonding device, according to some embodiments of the present disclosure. [Figure 5] 5 illustrates the shape of the upper bonding head of the bonding device of FIG. 4 according to some embodiments of the present disclosure. [Figure 6] 1 is a flowchart of a first exemplary method (or process flow) of bonding two wafers by using a bonding device, according to some embodiments of the present disclosure. [Figure 7] FIG. 10 is a schematic diagram of a second exemplary bonding device, according to some embodiments of the present disclosure. [Figure 8] 10 is a flowchart of a second exemplary method (or process flow) of bonding two wafers by using a bonding device, according to some embodiments of the present disclosure. [Figure 9] 10 is a flowchart of a third exemplary method (or process flow) of bonding two wafers by using a bonding device, according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] To achieve the highest resolution using masks with lithographic emulsions sensitive to laser or EMS λ (electromagnetic spectrum wavelengths) to define blocked or open areas for subsequent pattern transfer or implantation, the wafer surface must be optimally shaped before the photo / lithography process. The techniques disclosed herein include stress modification of films on the wafer to achieve target curvature or correction. The techniques disclosed herein can use any type of photosensitive wavelength / lithography type in the electromagnetic spectrum (some examples are photolithography, electron beam lithography, direct laser writing lithography, and x-ray lithography). The techniques disclosed herein also include applying local pressure to two wafers to bond them together based on bow measurements of the two wafers, thereby ensuring that the bonded wafers have an optimal wafer shape.

[0018] The techniques disclosed herein define several process flows to achieve an optimal starting wafer shape (either using semiconductor stress film tuning or by tuning its lattice) before the photo process used on the working surface of the wafer. The process flows herein include, as one option, providing a disposable stress tuning film on the backside of the wafer. Another option is to leave the stress tuning film in place for subsequent processing, for use in some cases where low temperature processing is possible for some steps.

[0019] Lithographic films can be used to pattern using a mask or by direct writing using features in the lithographic stress film. One unique aspect of the present disclosure is that the deposited lithographic films can have compressive, tensile, or neutral stress as deposited as a lithographic emulsion sensitive to specific laser or EM wavelengths. Thus, microstress regions can be defined by masking and etching the deposited film or by direct writing (or direct writing options) in areas where selective compressive / neutral / tensile regions are desired. To eliminate wafer bow after laser processing, the process can also be repeated using two different deposition methods (i.e., one sensitive to a first laser wavelength and the other sensitive to a second laser wavelength).

[0020] The techniques herein include wafer stress modification techniques to correct wafer bow and curvature for improved wafer overlay. Stress film deposition can be performed with the wafer face up or face down as an option for all process flows that have the option of clamping the wafer. The techniques herein also include bonding two wafers by applying localized pressure based on bow measurements of the two wafers.

[0021] Microfabrication of semiconductor structures 100 begins with a flat substrate or wafer 110, as shown in FIGS. 1A-1C. During microfabrication of semiconductor structures 100, multiple processing steps are performed, which may include material deposition on wafer 110, material removal, dopant implantation, annealing, baking, etc. The resulting different materials and structural formations 120 can induce internal stresses in wafer 110, resulting in bowing of semiconductor structures 100, which in turn affects overlay, typically resulting in overlay errors of various magnitudes. For example, FIGS. 1A and 1B illustrate how different materials and structural formations 120 can induce compressive or tensile stresses, respectively, in wafer 110, resulting in primary bowing, along with bow measurements indicating height deviations in the z-direction from a reference plane (not shown). As another example, FIG. 1C illustrates secondary bowing of wafer 110, along with two bow measurements identifying positive and negative z-direction height deviations, respectively.

[0022] If some regions of the two wafers 110 to be bonded together contain compressive or tensile stress, multiple pressure heads can be used to achieve localized pressure for a more efficient bonding process, thus improving die yield along with optimal wafer shape. Opposite types of stress can be applied in each of the localized nano-stress regions. By using an array of thermal / light zones or locations on the wafer chuck to modify the internal stress of the stress-modifying film, optimal wafer shape can be achieved quickly and at minimal cost.

[0023] 2 is a functional block diagram of an exemplary system 200 for bonding two or more wafers and / or dies according to some embodiments of the present disclosure. For example, the system 200 may include a metrology instrument, such as a warp measurement device 210, configured to measure a substrate, die, or wafer (e.g., the wafer 110 shown in FIGS. 1A-1C) to determine a warp measurement value of the wafer 110. In one embodiment, the warp measurement device 210 may use optical (e.g., using scanning laser technology), acoustic, and other mechanisms to measure height deviations in the z-direction across the surface of the wafer 110, store the height deviations by (x,y) coordinate, and determine multiple sub-warp measurements (x,y) of the warp measurement value. The height deviations in the z-direction may be mapped with various resolutions depending on the type of metrology instrument used and / or the desired resolution. The warp measurement value (and sub-warp measurements as well) may include raw warp data or may be expressed as a warp signature having a relative value. 1A, wafer 110 has a working surface 110A on which different materials and structure formations 120 can be formed, and a back surface 110B opposite working surface 110A. Wafer 110 may have an amount of wafer bow resulting from one or more micro-fabrication processing steps performed to create semiconductor structures, such as at least a portion of semiconductor structure 100, on working surface 110A of wafer 110. For example, transistor gates may be complete or only partially complete.

[0024] The system 200 may further include a deposition module, e.g., a film-forming device 220, configured to deposit and form films, e.g., stress-modifying films and bonding films, on the backside 110B and / or working surface 110A of the wafer 110 and / or die. For example, the film-forming device 220 may deposit the stress-modifying films and bonding films, respectively, on the backside 110B and working surface 110A of the wafer 110 by spin coating, lamination, spraying, or other suitable deposition techniques. The stress-modifying films may modify their internal stresses by heat / light upon exposure to and reaction with heat / light. The film-forming device 220 may be configured to form two or more stress-modifying films having different, e.g., opposing, stresses. The bonding films may bond the wafer and die to each other.

[0025] 3 , the system 200 may further include a heat / light generator 230 configured to generate a heat / light pattern 300. In one embodiment, the heat / light generator 230 may generate a laser, e.g., direct laser writing, and multiple light wavelengths. In another embodiment, the heat / light generator 230 may include multiple heating / illumination units, which may be mounted on the wafer chuck and have an arrangement corresponding to the heat / light pattern 300. For example, the heat / light generator 230 may include heating / illumination 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), for a total of 52 heating / illumination units, and the warpage measurement device 21 may include the heating / illumination 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). 0 can measure the wafer 110 to identify the warpage measurements of the wafer 110, including corresponding sub-warpage measurements (3,1) through (6,1), (2,2) through (7,2), (1,3) through (8,3), (1,4) through (8,4), (1,5) through (8,5), (1,6) through (8,6), (2,7) through (7,7), and (3,8) through (6,8). The thermal / light (Poseidon) micropattern 300 herein can eliminate the warpage so that high-resolution lithographic patterning can be maintained throughout all process steps for 3D stacking.

[0026] The heat / light generator (or heat generator) 230 may generate heat in multiple temperature ranges. For example, the heat generator 230 may generate heat in a first temperature range up to 200°C, a second temperature range from 200°C to 500°C, a third temperature range from 500°C to 800°C, and a fourth temperature range above 800°C.

[0027] Returning to FIG. 2, system 200 may further include a bonding device 240 configured to apply pressure to two wafers and / or dies (having a bonding film formed on at least one surface, e.g., a working surface) to bond the two wafers and / or dies to one another.

[0028] The system 200 may further include a controller 250 coupled to the warp measurement device 210, the film formation device 220, the light / heat generator 230, and the bonding device 240. The controller 250 may be configured to control the warp measurement device 210 to measure the wafer (and / or die) 110 to determine the warp measurements (and sub-warp measurements) of the wafer 110, control the film formation device 220 to form a stress modifying film and / or a bonding film on the backside 110B and / or working surface 110A of the wafer 110, control the heat / light generator 230 to generate and apply a heat / light pattern 300 to the stress modifying film, the heat / light pattern corresponding to the warp measurements (and sub-warp measurements), and further control the bonding device 240 to bond the two wafers 110 together. The controller 250 may be a computer processor located within the system 200 or a computer processor located remotely but in communication with the components of the system 200.

[0029] The system 200 may further include other components such as a wafer chuck for placing the wafer thereon, a robot handler configured to flip the wafer 110 and transfer the wafer between various devices and / or chambers, a wafer clamper configured to clamp the wafer 110, a coating device configured to coat the backside 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 an actinic radiation pattern, a developing device configured to develop a latent image in the photoresist, and an etching device configured to use plasma or gas-phase etching or wet etching.

[0030] 4 is a schematic diagram of an exemplary bonding device 400, e.g., bonding device 240 of system 200, according to some embodiments of the present disclosure. In one embodiment, 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., controller 250, to move toward and away from each other and apply pressure to a first wafer 430 and a second wafer 440, e.g., wafer 110, at least one of which has a bonding film 450 formed on a surface thereof, e.g., work surface 110A, for bonding the first wafer 430 and the second wafer 440 to each other. In one embodiment, bonding film 450 may be insulating and may include epoxy, metal, or a combination thereof.

[0031] In one embodiment, the bottom bonding chuck 410 may include a bottom bonding (or pressure) head 411, e.g., circular, for mounting the first wafer 430. The bottom bonding head 411 may apply an overall pressure (i.e., force / first wafer area) on the first wafer 430. The bottom bonding chuck 410 may further include one or more holes or holes (not shown) formed in its mounting surface 410a. A vacuum system may be coupled to the bottom bonding chuck 410 or a negative pressure may be transmitted to the first wafer 430 through the holes or holes to hold the first wafer 430 in place during the subsequent bonding process.

[0032] In one embodiment, the top bonding chuck 420 may include multiple top bonding (or pressure) heads 421 to which the second wafer 440 is attached. For example, the top bonding heads 421 may be arranged in a configuration corresponding to the heat / light pattern 300 and individually controlled by the controller 250 to apply localized pressure to the second wafer 440 based on bow measurements of the second wafer 440. The top bonding chuck 420 may also include one or more holes or apertures (not shown) formed in its mounting surface 420A. A vacuum system may be coupled to the top bonding chuck 420 or a negative pressure may be transmitted to the second wafer 440 through the holes or apertures to hold the second wafer 440 in place during the subsequent bonding process. The top bonding heads 421 may have various shapes. 5, the bonding device 500 may include a first group 521A of upper bonding heads 421 that are rectangular, e.g., square, a second group 521B of upper bonding heads 421 that are circular, and a third group 521C of upper bonding heads 421 that are crescent-shaped. In some embodiments, the heat / light generator 230 may include one or more groups of heating / illuminating units having different shapes.

[0033] 6 shows a flowchart of an exemplary method (or process flow) 600 for bonding two wafers by using a bonding device, according to some embodiments of the present disclosure. In various embodiments, some of the steps of the illustrated method 600 may be performed simultaneously or in a different order than that shown, or may be replaced by other method steps or omitted. Additional method steps may also be performed as needed. Aspects of method 600 may be performed by a system such as system 200 shown in and described with respect to the previous figures.

[0034] In step S610, the curvature / warpage of the first wafer 430 and the second wafer 440 to be bonded together is measured. For example, the warpage measurement device 210 can be used to measure the first wafer 430 and the second wafer 440 to determine the warpage measurements of the first wafer 430 and the second wafer 440.

[0035] In step S620, optionally, a stress-modifying film 610 may be formed on the backside of the first wafer 430 and the second wafer 440 and exposed to heat / light to modify the internal stress thereof by the heat / light and modify the curvature / warpage 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-modifying film 610 on the backside 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 bow measurement values ​​of the first wafer 430 and the wafer 440 to modify the internal stress of the stress-modifying film 610. The method 600 may then return to step S610 to measure the curvature / warpage of the first wafer 430 and the second wafer 440 having the stress-modifying film 610 formed on their backsides.

[0036] In step S630 following step S610 or step S620, a bonding film, for example, bonding film 450, may be formed on at least one working surface of first wafer 430 and second wafer 440. In an exemplary embodiment, a first bonding film 651 and a second bonding film 652 may be formed on the working surfaces of first wafer 430 and second wafer 440, respectively. For example, using film forming device 220, first bonding film 651 may be deposited and formed on the working surface of first wafer 430, and second bonding film 652 may be deposited and formed on the working surface of second wafer 440, in that order.

[0037] In step S640, the first wafer 430, with the first bonding film 651 formed on its work surface, is attached to the bottom bonding head 411 of the bottom bonding chuck 410. A vacuum system can then be turned on to transfer negative pressure to the first wafer 430 through holes or apertures in the mounting surface 410A (shown in FIG. 4 ) to hold the first wafer 430 in place during the subsequent bonding process.

[0038] In step S650, a second wafer 440 having a second bonding film 652 formed on its work surface is attached to the upper bonding head 421 of the upper bonding chuck 420. A vacuum system can transmit negative pressure to the second wafer 440 through holes or apertures in the attachment surface 420A (shown in FIG. 4) to hold the second wafer 440 in place during the subsequent bonding process. In one embodiment, steps S640 and S650 can be performed in different orders.

[0039] In step S660, the first wafer 430 and the second wafer 440 are bonded together. For example, the controller 250 can control the bottom bonding chuck 410 and the top bonding chuck 420 to align with each other and move the first bonding film 651 toward each other until the first bonding film 651 contacts the second bonding film 652, and can further control the bottom bonding head 411 to apply a global pressure to the first wafer 430 and the top bonding head 421 based on the warp measurement of the second wafer 440 to apply a local pressure to the second wafer 440 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 one embodiment, the bonding technique for the first bonding film 651 and the second bonding film 652 can include direct bonding, anodic bonding, adhesive bonding, solder bonding, eutectic bonding, etc.

[0040] In step S670, the bonded first and second wafers 430 and 440 are removed from the bottom bonding chuck 410 and second bonding chuck 420, respectively, for subsequent processing options, such as dicing into dies. For example, the vacuum system can be turned off, and the bonded first and second wafers 430 and 440 can be released from the bottom bonding chuck 410 and second bonding chuck 420, respectively. The bonded first and second wafers 430 and 440 thus have optimal wafer shapes.

[0041] 7 is a schematic diagram of an exemplary bonding device 700, such as bonding device 240 of system 200, according to some embodiments of the present disclosure. Bonding device 700 may include a top bonding chuck 420 and a bottom bonding chuck 710. Compared to bottom bonding chuck 410 of bonding device 400 shown in FIG. 4, bottom bonding chuck 710 of bonding device 700 further includes one or more heating units 721 disposed on bottom bonding head 411 and controlled by controller 250 to provide heat for curing bonding film 450.

[0042] 8 shows a flowchart of an exemplary method (or process flow) 800 for bonding two wafers by using a bonding device, such as bonding device 700, according to some embodiments of the present disclosure. Aspects of method 800 may be performed by a system such as system 200 shown in and described with respect to the previous figures. Method 800 may also include steps S610-S650 and S670 of method 600. In one embodiment, the method may further include step S760, which is performed between steps S650 and S670. In step S760, first wafer 430 and second wafer 440 are bonded together. For example, the controller 250 can control the bottom bonding chuck 710 and the top bonding chuck 420 to align them with each other and move them toward each other until the first bonding film 651 contacts the second bonding film 652, control the bottom bonding head 411 to apply global pressure to the first wafer 430 and the top bonding head 421 and apply local pressure to the second wafer 440 based on the warp measurement value of the second wafer 440, and further control the heating unit 721 to provide heat to harden the first bonding film 651 and the second bonding film 652 and bond the second bonding film 652 to the first bonding film 651, thereby bonding the second wafer 440 to the first wafer 430.

[0043] 9 shows a flowchart of an exemplary method (or process flow) 900 for bonding multiple dies to a wafer by using a bonding device, according to some embodiments of the present disclosure. Aspects of method 900 may be performed by a system such as system 200 shown in and described with respect to the previous figures. Method 900 differs from method 800 in that an upper bonding chuck 920 and multiple dies 940 are used in place of the upper bonding chuck 420 and second wafer 440 used in method 800 shown in FIG.

[0044] In step S910, the curvature / warpage of the first wafer 430 and the dies 940 to be bonded together is measured. For example, the warpage measurement device 210 can be used to measure the first wafer 430 and each die 940 to determine the warpage measurements of the first wafer 430 and the dies 940.

[0045] In step S920, optionally, a stress-modifying film 610 and a stress-modifying film 910 may be formed on the backside of the first wafer 430 and the die 940 and exposed to heat / light to modify their internal stress by the heat / light and modify the curvature / warpage of the first wafer 430 and the die 940. For example, the film-forming device 220 may be used to deposit and form the stress-modifying films 610 and 910 on the backside of the first wafer 430 and the die 940, respectively, and the heat / light generator 230 may be used to generate a heat / light pattern based on the warpage measurements of the first wafer 430 and each die 440 to modify the internal stress of the stress-modifying films 610 and 910. The method 900 may then return to step S910 to measure the curvature / warpage of the first wafer 430 and the die 940 having the stress-modifying films 610 and 910 formed on their backsides.

[0046] In step S930 following step S910 or step S920, a bonding film, for example, bonding film 450, can be formed on the working surfaces of first wafer 430 and / or die 940. In an exemplary embodiment, first bonding film 651 and second bonding film 952 can be formed on the working surfaces of first wafer 430 and die 940, respectively. For example, using film forming device 220, first bonding film 651 can be deposited and formed on the working surface of first wafer 430, and second bonding film 952 can be deposited and formed on the working surface of die 940, in sequence.

[0047] In step S940, the first wafer 430, with the first bonding film 651 formed on its work surface, is attached to the bottom bonding head 411 of the bottom bonding chuck 710 (or bottom bonding chuck 410). A vacuum system can then be turned on to transfer negative pressure to the first wafer 430 through holes or apertures in the mounting surface 410A (shown in FIG. 4) to hold the first wafer 430 in place during the subsequent bonding process.

[0048] In step S950, the dies 940, each having a second bonding film 952 formed on its work surface, are attached to the upper bonding head 921 of the upper bonding chuck 920 one by one. In one embodiment, the upper bonding heads 921 are arranged in a configuration corresponding to the heat / light pattern 300, for example, and can be individually controlled by the controller 250 based on the warpage measurements of the dies 440. The upper bonding chuck 920 may also include one or more holes or apertures (not shown) formed in its mounting surface 920a. A vacuum system is coupled to the upper bonding chuck 920 and can transmit negative pressure to each die 940 through the holes or apertures to hold the die 940 in place during the subsequent bonding process. The upper bonding head 921 can have various shapes. In step S950, the vacuum system can be turned on to transmit negative pressure to the die 940 through the holes or apertures in the mounting surface 920a to hold the die 940 in place during the subsequent bonding process. In one embodiment, steps S940 and S950 may be performed in a different order.

[0049] In step S960, the first wafer 430 and one of the dies 940 are bonded together. For example, the controller 250 can control the bottom bonding chuck 410 and the top bonding chuck 920 to align with each other and move the first bonding film 651 toward each other until the first bonding film 651 contacts the second bonding film 952, and can control the bottom bonding head 411 to apply a global pressure to the first wafer 430 and the top bonding head 921 and apply a local pressure to the die 940 based on the warpage measurement of the die 940 to bond the second bonding film 952 to the first bonding film 651, and thus bond the die 940 to the first wafer 430.

[0050] In step S970, the die 940 is removed from the top bonding chuck 920 for subsequent processing options, such as bonding another die. For example, the vacuum system can be turned off and the last die 940 can be released from the top bonding chuck 920. The bonded first wafer 430 and die 940 now have an optimal wafer / die shape.

[0051] In step S971, the portion of the first bonding film 651 that is not bonded to the second bonding film 952 may be etched away and replaced by a dielectric layer 960 that separates and insulates the dies 940 from each other.

[0052] In step S972, the curvature / warping of each of the other multiple dies 930 to be bonded to the die 940 is measured, a first bonding film 951 and a second bonding film 932 are formed on the backside of the die 940 and the other die 930, respectively, the other die 930 is attached to the upper bonding head 921 of the upper bonding device 920, and the upper bonding device 920 and the bottom bonding device 410 are controlled, aligned, and moved toward each other to bond the first bonding film 951 and the second bonding film 932 to each other.

[0053] In step S973, the die 940 and another die 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 with each other and move toward each other until the first bonding film 951 contacts the second bonding film 932, and can further control the bottom bonding head 411 to apply a global pressure to the die 940 and the top bonding head 921 and apply a local pressure to the another die 930 based on the warpage measurement value of the another die 930 to bond the second bonding film 932 to the first bonding film 951, and thus bond the die 940 to the another die 930.

[0054] In the preceding description, specific details have been disclosed, such as the particular shape of the processing system, descriptions of various elements and processes used within the system, etc. However, it should be understood that the techniques described herein can be practiced in other embodiments that deviate from these specific details, and that such details are for purposes of explanation, not limitation. The embodiments disclosed herein have been described with reference to the accompanying drawings. Similarly, for purposes of explanation, specific numerical values, materials, and configurations have been set forth to provide a thorough understanding. However, embodiments can be practiced without such specific details. Because components having substantially the same functional structure are designated by similar reference numerals, redundant description may be omitted.

[0055] It should be understood that the order of discussion of the various steps described herein has been presented for clarity. In general, these steps may be performed in any suitable order. In addition, although each of the various features, techniques, configurations, etc. herein may be discussed in different parts of this disclosure, it is contemplated that each of the concepts may be implemented independently of each other or in combination with each other. Accordingly, the present disclosure may be embodied and viewed in many different ways.

[0056] To aid in understanding various embodiments, various techniques have been described as multiple separate operations. The order of description should not be construed to imply that these operations are necessarily order dependent. In fact, these operations need not be performed in the order presented. The described operations may be performed in a different order than in the described embodiments. In additional embodiments, various additional operations may be performed and / or described operations may be omitted.

[0057] As used herein, "substrate" or "target substrate" refers generally to an object to be processed in accordance with the present disclosure. A substrate may include any material portion or structure of a device, particularly a semiconductor device or other electronic device, such as a base substrate structure, such as a semiconductor wafer, a reticle, or a layer (such as a thin film) on or superimposed on the base substrate structure. Thus, the substrate is not limited to any particular base structure, lower layer, or upper layer, patterned or unpatterned, but is intended to include any such layer or base structure and any combination of layers and / or base structures. While the above description may refer to a particular type of substrate, this is for illustrative purposes only.

[0058] Those skilled in the art will also understand that various modifications may be made to the operation of the above-described techniques while still achieving the same objectives of the present disclosure. Such modifications are intended to fall within the scope of the present disclosure. Accordingly, the above description of embodiments of the present disclosure is not intended to be limiting. Rather, any limitations to embodiments of the present disclosure are presented in the following claims.

Claims

1. A system for joining two wafers, A warpage measuring device configured to measure a first wafer and a second wafer and to determine the warpage measurements 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 warpage measuring 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 warpage measurement value, thereby bonding the first wafer to the second wafer. A film forming device coupled to the controller, comprising a film forming device configured to form bonding films on the first surfaces of the first wafer and the second wafer, The system further includes a heat generator coupled to the controller, configured to generate a heat pattern, the film forming device further configured to form first and second stress-correcting films on the second surfaces of the first and second wafers, respectively, the first and second stress-correcting films being reactive to heat, thereby the applied heat correcting the internal stress of the first and second stress-correcting films, and the warpage measuring device measures the first and second wafers, where the first and second stress-correcting films are present on their second surfaces, respectively, and their internal stress The warpage measuring device is further configured to measure the first wafer and the second wafer with the force corrected to determine the warpage measurements of the first wafer and the second wafer, and the warpage measuring device is further configured to measure the first wafer and the second wafer with no stress correction film formed on the second surface thereof to determine another warpage measurement of the first wafer and the second wafer, and the controller is further configured to control the heat generator to generate and apply the heat pattern to the first and second stress correction films, the heat pattern corresponding to the other warpage measurement, or The system further includes a photogenerator coupled to the controller, configured to generate patterns of first and second optical wavelengths, the film forming device further configured to form first and second stress-correcting films on the second surfaces of the first and second wafers, respectively, the first and second stress-correcting films being reactive to the first and second optical wavelengths, respectively, so that exposure to the first and second optical wavelengths corrects the internal stresses of the first and second stress-correcting films, respectively, and the warpage measuring device forming the first and second stress-correcting films on the second surfaces of the first and second wafers, respectively. The system further comprises a first wafer and a second wafer, the warpage measuring device being configured to determine the warpage measurements of the first wafer and the second wafer by measuring them with their internal stress corrected, the warpage measuring device being further configured to determine other warpage measurements of the first wafer and the second wafer by measuring them with no stress correction film formed on the second surface thereof, and the controller being further configured to control the light generator to generate first and second optical wavelength patterns and apply them to the first and second stress correction films, respectively, the first and second optical wavelength patterns corresponding to the other warpage measurements.

2. The system according to claim 1, wherein the second wafer is a die.

3. A method for joining two wafers, The steps include receiving the first wafer and the second wafer, The steps include measuring the first wafer and the second wafer to determine the warpage measurements of the first wafer and the second wafer, A step of bonding the first wafer to the second wafer by applying pressure to the second surface of the first wafer and the second wafer based on the warpage measurements of the first wafer and the second wafer, The process includes the step of forming a bonding film on the first surface of the first wafer, The method further includes the steps of: measuring the first wafer with no stress correction film formed on its second surface to identify another warpage measurement of the first wafer; forming a stress correction film on the second surface of the first wafer, wherein the stress correction film is reactive to heat, so that the applied heat corrects the internal stress of the stress correction film; and applying a thermal pattern to the stress correction film to correct the internal stress of the stress correction film, wherein the thermal pattern corresponds to the other warpage measurement, and the step of measuring the first wafer and the second wafer to identify the warpage measurements of the first wafer and the second wafer includes measuring the first wafer and the second wafer with the stress correction film formed on the second surface of the first wafer and its internal stress corrected to identify the warpage measurements of the first wafer and the second wafer, or The method further includes the steps of: measuring the first wafer with no stress correction film formed on its second surface to identify another warpage measurement of the first wafer; forming a stress correction film on the second surface of the first wafer, wherein the stress correction film is reactive to a light wavelength, such that exposure to the light wavelength corrects the internal stress of the stress correction film; and applying a pattern of light wavelengths to the stress correction film to correct the internal stress of the stress correction film, wherein the pattern of light wavelengths corresponds to the other warpage measurement, and the step of measuring the first wafer and the second wafer to identify the warpage measurements of the first wafer and the second wafer includes measuring the first wafer and the second wafer with the stress correction film formed on the second surface of the first wafer and the internal stress corrected to identify the warpage measurements of the first wafer and the second wafer.

4. The method according to claim 3, wherein the first wafer is a die.

5. The steps include measuring another die to determine a different warpage measurement of the other die, The method according to claim 4, further comprising the step of applying a different pressure to the first surface of the other die based on the other warpage measurement to bond the other die to the die.

6. The steps include measuring another die to determine a different warpage measurement of the other die, The method according to claim 4, further comprising the step of applying a different pressure to the first surface of the other die based on the other warpage measurement to bond the other die to the second wafer.

7. A bonding device for joining two wafers, A first bonding head, comprising a first bonding chuck having a first bonding head on which a first wafer is mounted, A second bonding chuck having a plurality of second bonding heads on which a second wafer is mounted, The second bonding head is configured to be individually controlled to apply local pressure to the second wafer, move the second wafer toward the first wafer, and bond the second wafer to the first wafer, wherein the local pressure corresponds to the warpage measurements of the first and second wafers. The first bonding chuck further includes one or more heating units positioned on the first bonding head, the heating units configured to provide heat for curing a bonding film used to bond the first wafer to the second wafer, or A bonding device in which the first of the second bonding heads has a first shape, and the second of the second bonding heads has a second shape different from the first shape.

8. The bonding device according to claim 7, wherein the first bonding head applies overall 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 device according to claim 7, wherein the second wafer is a die, and the second bonding head is arranged in a configuration that is sized to match the die.

10. The bonding device according to claim 7, wherein the first shape is circular.

11. The bonding device according to claim 7, wherein the first shape is rectangular.

12. The bonding device according to claim 7, wherein the first shape is crescent-shaped.

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