A method and system for decoupled compensation of dynamic errors in a bonding process

Abstract

The application discloses a dynamic error decoupling compensation method and system in a bonding process, and belongs to the technical field of semiconductor manufacturing. The method constructs a four-node angle monitoring architecture through a first reflector arranged on a bonding head, second and third reflectors arranged at the front end and the rear end of a vision module, and a preset mirror reflection area on a wafer, and performs unified coordinate transformation and time alignment on the angles of the nodes. After three-step calibration, the relative inclination of the bonding head is determined according to the relative change of the bonding head angle and the wafer reference surface angle, and the lateral position error at the bonding interface is calculated based on the effective Abbe arm calibrated in advance; the overall motion angle error of the vision module is determined according to the average angle change of the front end and the rear end reflectors of the vision module at two mark positions, and the relative angle error between the front end and the rear end is determined according to the change amount of the angle difference between the front end and the rear end at the same position.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a method and system for decoupling and compensating for dynamic errors during the bonding process. Background Technology

[0002] In the process of semiconductor packaging transitioning from "Moore's Law" to "Beyond Moore's Law," the requirements for bonding accuracy in hybrid bonding technology have increased from the micrometer level to the sub-micrometer and even nanometer level. As a core component of hybrid bonding equipment, the positioning accuracy of the vision alignment system directly determines the bonding quality and product yield. With the continuous increase in chip interconnect density and the continuous reduction in pad spacing, the alignment accuracy challenges faced by vision alignment systems are becoming increasingly severe.

[0003] The top-to-bottom vision alignment method is a widely used vision positioning scheme in current high-precision bonding equipment. Its basic workflow is as follows: after the bonding head moves to the preset bonding position, the vision module moves to two preset diagonal positions to identify and locate the chip markings and wafer markings respectively, calculates the positional deviation, and corrects it; then, the vision module moves away from the bonding area to a preset safe position; finally, the bonding head presses down to complete the chip mounting and bonding. Because this method performs vision positioning after the bonding head is in place, it reduces positioning errors caused by the movement of the bonding head to a certain extent.

[0004] However, in practical applications, the above methods still have the following shortcomings:

[0005] First, the detection position is separated from the working position. Existing solutions typically place the detection device at the rear end of the vision module, meaning the detection results cannot represent the actual working state of the front-end bonding head. The bonding head inevitably undergoes posture changes during its movement to the bonding position, and the rear-end detection device cannot capture these changes in real time, leading to inaccurate error compensation values ​​from posture detection. Furthermore, the separation of the detection and working positions causes asynchronous perception discrepancies between the front-end and rear-end postures of the same vision module during dynamic movement, further exacerbating the uncontrollability of positioning errors.

[0006] Secondly, even a slight tilt of the bonding head can introduce significant end-effector lateral errors through the effective Abbe arm. This effective Abbe arm is determined by the structural distance from the equivalent rotation center of the bonding head to the bonding interface, and is not equivalent to the real-time spacing between the chip and the wafer; even if the spacing between the chip and the wafer is small, the structural length of the bonding head may still amplify the bonding interface position deviation caused by the tilt.

[0007] Furthermore, the vision module itself has motion angle errors during movement. As the vision module moves to two diagonal positions for identification and positioning, its own motion angle errors further exacerbate the positioning deviation. Especially when the vision module needs to move back and forth between the two diagonal positions, the attitude changes of its front and rear ends are not completely synchronized. Simply relying on angle detection at a single position cannot accurately separate the vision module's motion angle error from the overall thermal drift error of the machine.

[0008] Furthermore, existing technologies lack a unified decoupling mechanism for multi-source errors. The three types of errors mentioned above—Abbe error introduced by bonding head tilt, vision module motion angle error, and machine thermal drift error—are often combined or only partially compensated in traditional solutions, failing to achieve independent tracking and classification compensation for each error source. While autocollimators have been used for angle measurement, existing solutions typically use only a single mirror to measure the angle change of a single object. They fail to construct a multi-node synchronous monitoring architecture covering the bonding head, vision module front end, vision module back end, and wafer mirror reference, and also cannot separate the independent contributions of each type of error from the coupled error signal through difference calculations between multiple mirrors and the wafer mirror. For example, the angle change detected by the vision module back end may simultaneously include machine thermal drift, the vision module's own motion angle error, and the bonding head's attitude change. Existing solutions cannot distinguish these error sources under the same measurement reference, resulting in limited compensation accuracy.

[0009] The aforementioned problems restrict further improvement in the alignment accuracy of bonding equipment, and there is an urgent need for a solution that can achieve decoupling and classification compensation of multi-source errors based on multi-node synchronous monitoring. Summary of the Invention

[0010] In view of this, embodiments of this application provide a decoupling compensation method and system for dynamic errors during the bonding process, so as to at least partially solve the above-mentioned problems.

[0011] According to a first aspect of the embodiments of this application, a decoupling compensation method for dynamic errors during bonding is provided, which is applied to the visual alignment process of a hybrid bonding device. The bonding head performs visual alignment, pressure application, force-controlled bonding, and retraction per cycle, including:

[0012] The bonding head angle, the front end angle, the back end angle of the vision module, and the wafer reference plane angle are obtained. Each angle contains two horizontal axis components and is aligned based on a unified coordinate system and sampling time.

[0013] The calibration process involves three steps: First, four angles are simultaneously acquired at the initial pose to establish a zero-position reference and the front and rear end mounting angle difference. Second, when the vision module moves to the first and second marked positions, at least the front and rear end angles are simultaneously acquired at each position. Third, before the lower surface of the chip and the upper surface of the wafer reach the preset safe distance and the bonding head switches to force control mode, the working angle of the bonding head and the working angle of the wafer reference surface are acquired to establish a dynamic compensation reference.

[0014] In actual operation, the changes in the relative calibration values ​​of each angle are obtained in real time according to the same coordinate system and time sequence;

[0015] The relative tilt of the bonding head relative to the wafer is determined based on the change in the bonding head angle and the wafer reference plane angle, and the lateral position error of the bonding interface is calculated based on the pre-calibrated effective Abbe arm. The overall motion angle error of the vision module is determined based on the average angle change of the front and rear end angles at the two marked positions, and the relative angle error between the front and rear ends is determined based on the change in the angle difference between the front and rear ends at the same position. The reference angle drift is determined based on the change in the wafer reference plane angle. The lateral position error, overall motion angle error, relative angle error between the front and rear ends, and reference angle drift are converted into position compensation amounts in the same plane coordinate system through a pre-calibrated angle-displacement conversion relationship to compensate for visual recognition deviations and bonding head positioning commands, and the positioning command is updated before the bonding head switches to force control mode.

[0016] In some embodiments, obtaining the bonding head angle, the front end angle of the vision module, the rear end angle of the vision module, and the wafer reference plane angle specifically includes: setting a first reflector on the bonding head, setting a second reflector on the front end of the vision module, setting a third reflector on the rear end of the vision module, and using a preset mirror reflection area on the wafer as the wafer reference plane.

[0017] An angle measurement unit is used to read the reflected light angle values ​​of the first reflector, the second reflector, the third reflector, and the wafer reference surface; the angle measurement unit includes a multi-channel autocollimator or multiple autocollimators, with each measurement channel aligned with the corresponding reflective surface;

[0018] Alternatively, the angle measurement unit includes an autocollimator and a beam switching mechanism. The beam switching mechanism guides the measurement beam to each reflecting surface in a preset order, and the sampled values ​​of each measurement channel are unified to the same compensation time through timestamp interpolation.

[0019] The preset mirror reflection area includes a blank pattern area, a dicing area, or a polished reflection area on the wafer. Each calibration and actual operation measures the same wafer coordinate position, or corrects the local surface slope at different measurement positions.

[0020] In some embodiments, the first reflector is rigidly connected to the bonding head, and the normal direction of its mirror surface is parallel to the axial movement direction of the bonding head; the angle measuring unit is mounted on a measuring frame independent of the machine tool, or mounted on a fixed base on the machine tool and the coordinate transformation relationship of the fixed base relative to the machine tool is pre-calibrated.

[0021] In some embodiments, the three-step calibration specifically includes:

[0022] The first step is to simultaneously calibrate the zero-position angles of the first, second, and third mirrors and the wafer reference plane under the initial reference pose, and determine the mounting angle difference based on the zero-position angle difference between the second and third mirrors.

[0023] The second step includes:

[0024] S21, control the vision module to move to the first mark position, and at the same sampling moment when the first set of chip marks and wafer marks are positioned, simultaneously calibrate the angles of the first reflector, the second reflector, the third reflector and the wafer reference plane;

[0025] S22, control the vision module to move to the second mark position, and at the same sampling moment when the second set of chip marks and wafer marks are positioned, simultaneously calibrate the angles of the first reflector, the second reflector, the third reflector and the wafer reference plane;

[0026] Wherein, the first mark position and the second mark position are two diagonal observation positions when the vision module identifies chip marks and wafer marks; the calibration benchmark for the overall motion angle error of the vision module is determined based on the average angle change of the front end angle and the rear end angle of the vision module at the two mark positions, and the calibration benchmark for the relative angle error between the front and rear ends is determined based on the difference between the rear end angle and the front end angle of the vision module at the same mark position;

[0027] The third step is to calibrate the working angle of the bonding head and the working angle of the wafer reference surface when the distance h between the lower surface of the chip picked up by the bonding head and the upper surface of the wafer is 0.1mm to 0.5mm and the bonding head has not yet switched to force control bonding mode, and to establish a dynamic compensation reference.

[0028] In some embodiments, the third step is performed when the distance h between the lower surface of the chip and the upper surface of the wafer is 0.2 mm to 0.4 mm.

[0029] In some embodiments, determining the relative tilt of the bonding head relative to the wafer based on the change and calculating the dynamic Abbe error specifically includes:

[0030] According to Δθ1(t) = θ1(t) - θ BHDetermine the angle change of the bonding head, and based on Δθ W (t)=LPF[θ W (t)-θ W0 Determine the thermally induced reference angle drift of the wafer reference plane; where θ1(t) is the real-time angle of the first reflector, θ W (t) represents the real-time angle of the wafer reference plane, θ BH and θ W0 For the third calibration step, LPF represents low-pass filtering;

[0031] For the same angular component, calculate the relative tilt of the bonding head relative to the wafer reference plane: Δθ Hrel (t)=Δθ1(t)-Δθ W (t);

[0032] Calculate the dynamic Abbe error based on the pre-calibrated effective Abbe arm: e H (t)=A H sin[Δθ] Hrel (t)];where e H (t) is the lateral position error vector at the bonding interface, A H The pre-calibrated effective Abbe arm coefficient matrix;

[0033] The effective Abbe arm coefficient matrix is ​​determined based on the structural distance from the equivalent rotation center of the bonding head to the bonding interface, or it is calibrated by applying a known angular displacement to the bonding head and measuring the lateral displacement at the bonding interface.

[0034] In some embodiments, the overall motion angle error of the visual module and the relative angle error between the front and rear ends are determined in the following manner:

[0035] Calculate the overall angle of the visual module at the first and second marked positions respectively: θ C,M1 =(θ 2M1 +θ 3M1 ) / 2, θ C,M2 =(θ 2M2 +θ 3M2 ) / 2; where θ 2M1 θ 3M1 θ represents the angles of the second and third reflecting mirrors at the first marked position. 2M2 θ 3M2 These are the angles of the second and third reflecting mirrors at the second marked position, respectively.

[0036] According to Δθ Cam =[θ C,M2 -θ C,M1 ]-[θ WM2 -θ WM1Determine the overall motion angle error of the vision module; where θ WM1 and θ WM2 These are the angles of the wafer reference plane at the corresponding mark positions; when the vision module moves between the two mark positions, the wafer carrier stage maintains the same mark position posture, or the command posture change of the wafer carrier stage is deducted during calculation;

[0037] According to δθ Cam =[θ 3M2 -θ 2M2 ]-[θ 3M1 -θ 2M1 The relative angle error between the front and rear ends of the vision module is determined; the overall motion angle error of the vision module and the relative angle error between the front and rear ends are used to correct the visual recognition coordinates.

[0038] In some embodiments, the compensation for visual recognition deviation and bonding head positioning command specifically includes:

[0039] Establish a unified planar coordinate system, and pre-calibrate the angle-displacement transformation matrix A corresponding to the relative tilt of the bonding head, the overall motion angle of the vision module, the relative angle between the front and rear ends, and the reference angle drift. H A C A D and A W Where AH is the pre-calibrated effective Abbe arm coefficient matrix; according to:

[0040] [ΔX cmd ,ΔY cmd ] T =[ΔX vis,corr ,ΔY vis,corr ] T +A H sin(Δθ) Hrel )+A C sin(Δθ) Cam )+A D ·sin(δθ Cam )+A W sin(Δθ) W Generate bonding head positioning instructions;

[0041] Where, Δθ Hrel Δθ is the relative tilt of the bonding head relative to the wafer. Cam δθ represents the overall motion angle error of the vision module. Cam Let Δθ be the relative angle error between the front and rear ends. W Let be the reference angle drift, where the superscript T denotes vector transpose, and sin(·) indicates that each component of the angle vector is calculated separately, [ΔX vis,corr ,ΔY vis,corr ]T This is the visual recognition deviation after deducting the measurement deviation caused by the visual module angle error and the reference angle drift.

[0042] In some embodiments, before calculating the dynamic Abbe error, the method further includes: obtaining the acceleration information of the bonding head during the pressing stroke, and correcting the angle change of the bonding head according to a pre-calibrated dynamic angle response coefficient;

[0043] The correction is based on Δθ 1corr (t)=Δθ1(t)-Ka·a(t) is executed; where a(t) is the acceleration vector of the bonding head, and Ka is the dynamic angle response coefficient matrix obtained by calibrating the angle response under different acceleration conditions.

[0044] In some embodiments, the method further includes: obtaining bonding quality detection results after bonding is completed;

[0045] Based on the residual between the bonding quality test result and the position compensation amount, at least one of the dynamic compensation benchmark, the effective Abbe arm coefficient matrix, and each of the angle-displacement transformation matrices is iteratively updated.

[0046] According to a first aspect of the embodiments of this application, a decoupling compensation system for dynamic errors during bonding is provided, characterized in that it includes:

[0047] The bonding head is used to pick up the chip to be bonded and perform the bonding operation.

[0048] The vision module is used to identify and locate chip markings and wafer markings;

[0049] Angle measurement unit, used to measure the angle change of the reflecting surface;

[0050] A first reflector is disposed on the bonding head; a second reflector is disposed at the front end of the vision module; a third reflector is disposed at the rear end of the vision module; a wafer is supported on the support platform of the machine, and a preset mirror reflection area on the wafer serves as the wafer reference surface;

[0051] The control unit, which is signal-connected to the angle measuring unit, is configured to perform any of the methods described above.

[0052] In some embodiments, the angle measurement unit includes a multi-channel autocollimator or multiple autocollimators, each measurement channel being used to read the reflected light angle values ​​of the first reflector, the second reflector, the third reflector, and the wafer reference surface, respectively;

[0053] Alternatively, the angle measurement unit includes an autocollimator and a beam switching mechanism, and the control unit aligns the angles of each reflecting surface to the same compensation time based on the timestamps of each measurement channel.

[0054] According to a first aspect of the embodiments of this application, a bonding apparatus is provided, characterized in that it includes the decoupling compensation system for dynamic errors during the bonding process described above.

[0055] According to a first aspect of the embodiments of this application, a computer-readable storage medium is provided, on which a computer program is stored, characterized in that, when the computer program is executed by a processor, it implements the steps of the method described in any of the preceding claims.

[0056] The beneficial effects of this application include:

[0057] a. Achieve decoupling and classification compensation for multi-source errors

[0058] This application constructs a four-node angle monitoring architecture by setting first to third reflective mirrors at the bonding head, the front end of the vision module, and the rear end of the vision module, and using a preset mirror reflection area on the wafer as the wafer reference surface, in conjunction with an angle measurement unit. Based on this, the overall motion angle error of the vision module is separated according to the average angle change of the front and rear reflective mirrors at two marked positions; the relative angle error between the front and rear reflective mirrors at the same marked position is separated according to the change in the angle difference between the front and rear reflective mirrors; the reference angle drift is separated according to the change in the wafer reference surface angle; and the relative tilt of the bonding head relative to the wafer is obtained according to the difference between the bonding head angle change and the wafer reference surface angle change. Thus, each error component is tracked, quantified, and classified for compensation separately under the same coordinate system and the same sampling time sequence, reducing the compensation uncertainty caused by the aliasing of multiple error sources.

[0059] b. Improve bonding positioning accuracy during the bonding head pressing process.

[0060] This application establishes a dynamic compensation reference when the lower surface of the chip picked up by the bonding head reaches a preset safe distance from the upper surface of the wafer, and before the bonding head switches to force-controlled bonding mode, making the compensation reference closer to the actual bonding pose. Subsequently, based on the relative tilt of the bonding head relative to the wafer reference surface and the pre-calibrated effective Abbe arm, the lateral position error at the bonding interface is calculated, and the bonding head positioning command is updated before switching to force-controlled bonding mode, thereby improving the alignment accuracy of the bonding head end.

[0061] c. Achieve dynamic compensation for multi-source errors throughout the bonding process.

[0062] The four-node angle monitoring architecture of this application performs unified coordinate transformation and time alignment on the angles of the bonding head, the front end of the vision module, the back end of the vision module, and the wafer reference plane during actual operation. The relative tilt of the bonding head, the overall motion angle error of the vision module, the relative angle error between the front and back ends, and the reference angle drift are calculated separately and then converted into position compensation amounts in the same plane coordinate system through a pre-calibrated angle-displacement transformation matrix. These compensation amounts are then combined with the corrected visual recognition deviation to achieve dynamic compensation throughout the bonding process.

[0063] d. Comprehensively improve bonding quality and product yield

[0064] This application employs an error tracing and classification compensation mechanism to achieve synergistic compensation across three dimensions: bonding head posture detection, vision module motion control, and machine reference stability monitoring. A first reflector monitors the dynamic tilt of the bonding head relative to the wafer reference plane; a second and third reflector work together to distinguish between the overall motion angle error of the vision module and the relative angle error between the front and rear ends; a pre-set mirror reflection area on the wafer provides reference angle changes on the support stage side. These error components are converted into position compensation values ​​and then comprehensively compensated, reducing residual offset at the bonding interface and supporting high-precision alignment in hybrid bonding. Attached Figure Description

[0065] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0066] Figure 1 This is a schematic diagram of a bonding device and a first marker position calibration state provided in an embodiment of this application;

[0067] Figure 2 This is a schematic diagram of the second marker position calibration state provided in an embodiment of this application;

[0068] Figure 3 This is a schematic diagram of the bonding pose calibration state provided in an embodiment of this application;

[0069] Figure 4 This is a schematic diagram of the first and second marker positions provided in an embodiment of this application;

[0070] Figure 5 This is a schematic diagram of the error decoupling calculation principle provided in an embodiment of this application;

[0071] Figure 6 This is a flowchart of a three-step calibration process provided in an embodiment of this application;

[0072] Figure 7 This is a flowchart of a bonding operation provided in an embodiment of this application. Detailed Implementation

[0073] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the technical solutions in the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0074] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0075] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. In this application, "chip to be bonded" refers to a chip picked up by the bonding head and to be bonded to the wafer; "wafer reference surface" refers to a preset specular reflection area on the wafer used for angle measurement, which can be a blank pattern area, a scribe line area, or a polished reflective area; "effective Abbe arm" refers to the equivalent structural distance or calibrated equivalent coefficient used to convert the angular displacement of the bonding head into the lateral position error of the bonding interface. The English word for wafer is Wafer, which is also called Substrate, and its meaning and actual function are equivalent; the bonding component, i.e., chip, is called Die or chip, and its meaning and actual function are equivalent.

[0076] Please see Figure 1The bonding apparatus 100 provided in this embodiment may include a machine base 60, a carrier stage 10, a bonding head 20, a vision module 30, and an angle measurement unit. The carrier stage 10 is mounted on the machine base 60 and is used to support a wafer 70. A preset mirror reflection area is provided on the wafer 70. This preset mirror reflection area can be a blank pattern area, a dicing area, or a polished reflective area, used to provide a wafer reference surface. The bonding head 20 is positioned above the carrier stage 10 and can move vertically (Z-axis) to pick up the chip 80 to be bonded and perform the bonding operation. A first reflector 51 is rigidly mounted on the housing of the bonding head 20, with its mirror normal direction parallel to the axial movement direction of the bonding head 20. The vision module 30 is positioned on one side of the bonding head 20 and is equipped with an upper camera and a lower camera. The alignment observation unit 31 can move horizontally to a preset mark position for identifying and locating chip marks and wafer marks. The front end of the vision module 30 is equipped with a second reflector 52, and the rear end is equipped with a third reflector 53.

[0077] The angle measurement unit may include a multi-channel autocollimator 40 or multiple autocollimators 40, with each measurement channel aligned with the first reflector 51, the second reflector 52, the third reflector 53, and the wafer reference surface, respectively, to simultaneously obtain the two-axis angle components of each reflecting surface. Alternatively, the angle measurement unit may also include an autocollimator 40 and a beam switching mechanism. The beam switching mechanism guides the measurement beam to each reflecting surface in a preset sequence, and the control unit interpolates the sampled values ​​to the same compensation time based on the timestamps of each channel. The autocollimator 40 may be mounted on a metrology frame independent of the instrumentation platform 60; when the autocollimator 40 is mounted on a fixed base on the instrumentation platform 60, the coordinate transformation relationship of the fixed base relative to the instrumentation platform 60 is pre-calibrated. Thus, the angle measurement values ​​of the four monitoring nodes can be compared under a unified coordinate system and a unified sampling time.

[0078] The above three-step calibration process is as follows: Figure 6 As shown. Based on the above hardware architecture, this application establishes a dynamic compensation benchmark through a three-step calibration. The core logic of the three-step calibration is as follows: First, establish a four-node zero-position benchmark and the installation angle difference of the front and rear reflectors of the vision module; second, establish calibration benchmarks for the overall motion angle error of the vision module and the relative angle error between the front and rear ends at two marked positions; third, establish a dynamic compensation benchmark for the working posture of the bonding head and the wafer reference surface before the bonding head switches to the force-controlled bonding mode.

[0079] The first step is initial zero-position calibration. After the initial installation and debugging of the bonding device 100 is completed, the angle measurement unit synchronously reads the initial angle θ of the first reflecting mirror 51. 10 The initial angle θ of the second reflecting mirror 52 20 The initial angle θ of the third reflecting mirror 53 30 The initial angle θ with the wafer reference planeWref Establish an angle zero-position reference, and based on θ 30 With θ 20 The difference between them determines the installation angle difference β0 = θ between the two visual mirrors. 30 -θ 20 Each angle includes angular components about two mutually perpendicular horizontal axes.

[0080] The second step is to mark the positioning attitude calibration, which is further divided into two sub-steps, corresponding to the attitude recording when the alignment observation unit 31 moves to the first mark position 71 and the second mark position 72, respectively.

[0081] In sub-step S21, such as Figure 1 As shown, the vision module 30 is controlled to move to the first marker position 71. Figure 4 As shown, the first marker position 71 is the position of Wafer Mark 1. After the alignment observation unit 31 completes the identification and positioning of Die Mark 1 and Wafer Mark 1, at the same positioning sampling time, the angle measurement unit synchronously calibrates the angle θ of the first reflecting mirror 51. 1M1 The angle θ of the second reflecting mirror 52 2M1 The angle θ of the third reflecting mirror 53 3M1 Angle θ with the wafer reference plane WM1 .

[0082] In sub-step S22, such as Figure 2 As shown, the control alignment observation unit 31 moves from the first marker position 71 to the second marker position 72. Figure 4 As shown, the second marker position 72 is the Wafer Mark 2 position. After the alignment observation unit 31 completes the identification and positioning of Die Mark 2 and Wafer Mark 2, at the same positioning sampling time, the angle measurement unit synchronously calibrates the angle θ of the first reflecting mirror 51. 1M2 The angle θ of the second reflecting mirror 52 2M2 The angle θ of the third reflecting mirror 53 3M2 Angle θ with the wafer reference plane WM2 .

[0083] From a physical perspective, the overall angular motion of the vision module 30 is a common-mode component for the second reflector 52 and the third reflector 53, while the torsion or local deformation of the front and rear structures is a differential-mode component for them. Therefore, this application uses the average angle of the two reflectors to represent the overall attitude of the vision module 30, and uses the angle difference between the two reflectors at the same marked position to represent the relative attitude of the front and rear ends. By calculating the angle change of the same reflector at different marked positions, the installation angle difference of the reflector itself can be eliminated; by subtracting the common-mode reference change represented by the wafer reference plane or the first reflector, the overall motion angular error of the vision module can be separated.

[0084] After completing the second step of calibration, proceed to the third step, which is the bonding pose calibration. For example... Figure 3 As shown, the bonding head 20, which picks up the chip 80 to be bonded, presses down, so that the distance h between the lower surface of the chip 80 and the upper surface of the wafer 70 reaches 0.1mm to 0.5mm, preferably 0.2mm to 0.4mm, and more preferably 0.3mm; this distance is a preset safety gap before the bonding head 20 switches to force-controlled bonding mode. In this state, the angle measuring unit calibrates the angle θ of the first reflector 51. BH Angle θ with the wafer reference plane W0 and with θ BH and θ W0 As a dynamic compensation benchmark, lateral position compensation is completed before the bonding head 20 switches to force-controlled bonding mode to avoid the continued superposition of lateral position commands during the force-controlled stage.

[0085] After completing the three-step calibration, the actual bonding operation phase begins. The workflow for each bonding cycle is as follows: Figure 7 As shown. Figure 5 As shown, in each bonding cycle, the angle measurement unit reads the real-time angles θ1(t) of the first reflector 51, θ2(t) of the second reflector 52, θ3(t) of the third reflector 53, and the real-time angle θ of the wafer reference plane according to a unified coordinate system and a unified sampling time. W (t). For the implementation using a beam switching mechanism, the sampled values ​​of each channel are interpolated to the same compensation time based on the timestamp. Then, based on the amount of change between each real-time angle and the corresponding calibration value, the relative tilt of the bonding head, the overall motion angle error of the vision module, the relative angle error between the front and rear ends, and the reference angle drift are determined respectively.

[0086] For the bonding head 20, based on the real-time angle θ1(t) of the first reflector 51 and the calibration value θ in the third step... BH The difference yields the change in bonding head angle Δθ1(t) = θ1(t) - θ BH Based on the real-time angle θ of the wafer reference plane. W (t) and the calibration value θ in the third step W0 The difference is calculated and then low-pass filtered to obtain the thermally induced reference angle drift Δθ. W (t)=LPF[θ W (t)-θ W0 For the same angular component, calculate the relative tilt Δθ of the bonding head 20 relative to the wafer reference plane. Hrel (t)=Δθ1(t)-Δθ W (t).

[0087] For visual module 30, the overall angle θ is calculated at the first marker position 71 and the second marker position 72 respectively. C,M1 =(θ 2M1 +θ 3M1 ) / 2, θ C,M2 =(θ 2M2 +θ 3M2 ) / 2. The overall motion angle error of the vision module is calculated according to Δθ Cam =[θ C,M2 -θ C,M1 ]-[θ WM2 -θ WM1 [Confirmed; relative angle error between front and rear ends is calculated according to δθ] Cam =[θ 3M2 -θ 2M2 ]-[θ 3M1 -θ 2M1 Determined. Wherein, Δθ Cam δθ is used to characterize the overall angular motion of the visual module 30 between the two marked positions. Cam Used to characterize the relative torsion or local deformation of the front and rear ends of the vision module 30. When the vision module 30 moves between two marked positions, the support platform 10 maintains the same marked pose; if the support platform 10 undergoes a commanded movement, the corresponding commanded pose change is deducted first during the calculation.

[0088] It should be noted that the above-mentioned visual module error calculation relies on the spatial layout of the second reflector 52 and the third reflector 53, which are respectively located at the front and rear ends of the visual module 30, and the calibration process of synchronously acquiring the angles of the two reflectors at each marked position. Compared with the method of reading the front angle only at the first marked position and the rear angle at the second marked position, this embodiment eliminates the influence of the reflector installation angle difference and the acquisition time difference on the calibration results by synchronously acquiring the same position and the change of the same reflector between the two positions.

[0089] For reference angle drift, the angular change Δθ of the wafer reference plane W (t) primarily characterizes the thermally induced angular change of the wafer 70 and the stage 10 relative to the angle measurement unit. When the autocollimator 40 is mounted on the instrument 60, this change reflects the relative angular drift between the autocollimator mount and the stage 10; when the autocollimator 40 is mounted on an independent metrology frame, this change reflects the angular change of the wafer reference plane relative to an external metrology reference. To suppress vibration and transient measurement noise, the angular sequence of the wafer reference plane can be low-pass filtered, and the filtered slow-varying component can be used as the thermally induced reference angular drift.

[0090] In obtaining the relative tilt Δθ of the bonding head Hrel (t) After that, the lateral position error at the bonding interface is calculated based on the effective Abbe arm: e H (t)=AH sin[Δθ] Hrel [t], when the angle is small, can be approximated as e H (t)=A H ·Δθ Hrel (t). Among them, A H The effective Abbe arm coefficient matrix is ​​determined based on the structural distance from the equivalent rotation center of the bonding head 20 to the bonding interface, or calibrated by applying a known angular displacement to the bonding head 20 and measuring the lateral displacement at the bonding interface. The real-time spacing between the chip 80 and the wafer 70 is used to control the pressing stroke and is not directly considered as the effective Abbe arm.

[0091] Subsequently, each angular error is converted into a position compensation value in the same plane coordinate system to complete the comprehensive compensation:

[0092] [ΔX cmd ,ΔY cmd ] T =[ΔX vis,corr ,ΔY vis,corr ] T +A H sin(Δθ) Hrel )+A C sin(Δθ) Cam )+A D ·sin(δθ Cam )+A W sin(Δθ) W ).

[0093] Among them, [ΔX vis,corr ,ΔY vis,corr ] T The visual recognition deviation is the result after deducting the measurement deviation caused by the visual module angle error and the reference angle drift; A H A C A D and A W These are pre-calibrated angle-displacement transformation matrices. The aforementioned compensation amounts are superimposed on the X / Y positioning command of the bonding head 20 in the form of displacement amounts, avoiding direct addition of angle and displacement amounts and avoiding repeated compensation for the same error component.

[0094] To illustrate the role of the effective Abbe arm, a theoretical estimate is used as an example: when the effective Abbe arm L = 15 mm and the relative tilt angle of the bonding head θ = 10 μrad, the lateral error on one side of the bonding interface is approximately L·sinθ ≈ 150 nm. If only the 0.3 mm process gap between the chip and the wafer is considered as the lever arm, the displacement corresponding to the same tilt angle is approximately 3 nm, a significant difference. Therefore, this application defines the effective Abbe arm separately from the chip-wafer process gap and calculates the lateral position error at the bonding interface based on the effective Abbe arm. The actual compensated accuracy is affected by factors such as angle measurement resolution, time synchronization accuracy, structural stiffness, control bandwidth, and calibration residuals.

[0095] To more intuitively illustrate the error decoupling relationship of this application, the following table shows the calculation basis and compensation object of each error component:

[0096]

[0097] From the perspective of measurement principles, the ability of different monitoring methods to identify error components can be compared as follows:

[0098]

[0099] As shown in the table above, a single reflector or simply increasing the number of reflectors cannot automatically achieve error decoupling. Only when each monitoring node has a unified measurement benchmark and a unified sampling sequence, and when the average angle and angle difference between the front and rear ends of the vision module are used for calculation, can the overall motion angle error of the vision module be distinguished from the relative angle error between the front and rear ends. Furthermore, by combining the wafer reference plane and the pre-calibrated angle-displacement transformation matrix, each angle error can be converted into a position compensation amount in the same coordinate system.

[0100] Furthermore, the error decoupling algorithm of this application is not independent of the hardware structure. The algorithm relies on the spatial layout of the second reflector 52 and the third reflector 53 respectively set at the front and rear of the vision module 30, and the calibration process of synchronously acquiring the angles of the two reflectors at each marked position; at the same time, it relies on the first reflector 51 and the wafer reference plane to provide a unified reference for the relative tilt of the bonding head.

[0101] The above technical solution, through error decoupling and classification compensation mechanisms, tracks and converts the relative tilt of the bonding head, the overall motion angle of the vision module, the relative angle between the front and rear ends of the vision module, and the reference angle drift into position compensation values ​​respectively, thereby reducing the risk of multi-source error aliasing and repeated compensation. Directly using the preset mirror reflection area on the wafer as the reference for the support stage can also reduce the impact of installation errors and added mass of additional mirrors on the dynamic characteristics of the machine.

[0102] Furthermore, as a preferred embodiment of this application, in actual bonding operations, the bonding head 20 undergoes an acceleration phase, a constant speed phase, and a deceleration phase during the pressing process. Inertial forces may cause dynamic angular responses in the local structure of the first reflector 51 or the bonding head 20. Therefore, before calculating the dynamic Abbe error, the acceleration vector a(t) of the bonding head 20 during the pressing stroke can be obtained and calculated according to Δθ. 1corr The formula (t) = Δθ1(t) - Ka·a(t) corrects for the change in bonding head angle. Here, Ka is the dynamic angle response coefficient matrix, which can be obtained by calibrating the angle response under different acceleration conditions.

[0103] Furthermore, as another preferred embodiment of this application, after bonding is completed, bonding quality inspection results (such as bonding offset, bonding strength, etc.) can be obtained, and the dynamic compensation benchmark and the effective Abbe arm coefficient matrix A can be iteratively updated based on the residual between the bonding quality inspection results and the position compensation amount. H and the angle-displacement transformation matrix A C A D A W At least one of the following enables the compensation parameters for subsequent bonding cycles to be updated as the batch or equipment status changes.

[0104] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this application.

[0105] The above embodiments are only used to illustrate the embodiments of this application, and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application. The patent protection scope of the embodiments of this application shall be determined by the contents of the appended claims.

Claims

1. A method for decoupling and compensating for dynamic errors during bonding, characterized in that, The vision alignment process used in hybrid bonding equipment involves the bonding head performing vision positioning, pressing down, force-controlled bonding, and retraction per cycle, including: The bonding head angle, the front end angle, the back end angle of the vision module, and the wafer reference plane angle are obtained. Each angle contains two horizontal axis components and is aligned based on a unified coordinate system and sampling time. The calibration process involves three steps: First, four angles are simultaneously acquired at the initial pose to establish a zero-position reference and the front and rear end mounting angle difference. Second, when the vision module moves to the first and second marked positions, at least the front and rear end angles are simultaneously acquired at each position. Third, before the lower surface of the chip and the upper surface of the wafer reach the preset safe distance and the bonding head switches to force control mode, the working angle of the bonding head and the working angle of the wafer reference surface are acquired to establish a dynamic compensation reference. In actual operation, the changes in the relative calibration values ​​of each angle are obtained in real time according to the same coordinate system and time sequence; The relative tilt of the bonding head relative to the wafer is determined based on the change in the bonding head angle and the wafer reference plane angle, and the lateral position error of the bonding interface is calculated based on the pre-calibrated effective Abbe arm. The overall motion angle error of the vision module is determined based on the average angle change of the front and rear end angles at the two marked positions, and the relative angle error between the front and rear ends is determined based on the change in the angle difference between the front and rear ends at the same position. The reference angle drift is determined based on the change in the wafer reference plane angle. The lateral position error, overall motion angle error, relative angle error between the front and rear ends, and reference angle drift are converted into position compensation amounts in the same plane coordinate system through a pre-calibrated angle-displacement conversion relationship to compensate for visual recognition deviations and bonding head positioning commands, and the positioning command is updated before the bonding head switches to force control mode.

2. The method according to claim 1, characterized in that, The acquisition of the bonding head angle, the front end angle of the vision module, the rear end angle of the vision module, and the wafer reference plane angle specifically includes: setting a first reflector on the bonding head, setting a second reflector on the front end of the vision module, setting a third reflector on the rear end of the vision module, and using a preset mirror reflection area on the wafer as the wafer reference plane. An angle measurement unit is used to read the reflected light angle values ​​of the first reflector, the second reflector, the third reflector, and the wafer reference surface; the angle measurement unit includes a multi-channel autocollimator or multiple autocollimators, with each measurement channel aligned with the corresponding reflective surface; Alternatively, the angle measurement unit includes an autocollimator and a beam switching mechanism. The beam switching mechanism guides the measurement beam to each reflecting surface in a preset order, and the sampled values ​​of each measurement channel are unified to the same compensation time through timestamp interpolation. The preset mirror reflection area includes a blank pattern area, a dicing area, or a polished reflection area on the wafer. Each calibration and actual operation measures the same wafer coordinate position, or corrects the local surface slope at different measurement positions.

3. The method according to claim 2, characterized in that, The first reflector is rigidly connected to the bonding head, and the normal direction of its mirror surface is parallel to the axial movement direction of the bonding head; the angle measuring unit is installed on a measuring frame independent of the machine tool, or on a fixed base on the machine tool and the coordinate transformation relationship of the fixed base relative to the machine tool is pre-calibrated.

4. The method according to claim 1, characterized in that, The three-step calibration specifically includes: The first step is to simultaneously calibrate the zero-position angles of the first, second, and third mirrors and the wafer reference plane under the initial reference pose, and determine the mounting angle difference based on the zero-position angle difference between the second and third mirrors. The second step includes: S21, control the vision module to move to the first mark position, and at the same sampling moment when the first set of chip marks and wafer marks are positioned, simultaneously calibrate the angles of the first reflector, the second reflector, the third reflector and the wafer reference plane; S22, control the vision module to move to the second mark position, and at the same sampling moment when the second set of chip marks and wafer marks are positioned, simultaneously calibrate the angles of the first reflector, the second reflector, the third reflector and the wafer reference plane; Wherein, the first mark position and the second mark position are two diagonal observation positions when the vision module identifies chip marks and wafer marks; the calibration benchmark for the overall motion angle error of the vision module is determined based on the average angle change of the front end angle and the rear end angle of the vision module at the two mark positions, and the calibration benchmark for the relative angle error between the front and rear ends is determined based on the difference between the rear end angle and the front end angle of the vision module at the same mark position; The third step is to calibrate the working angle of the bonding head and the working angle of the wafer reference surface when the distance h between the lower surface of the chip picked up by the bonding head and the upper surface of the wafer is 0.1mm to 0.5mm and the bonding head has not yet switched to force control bonding mode, and to establish a dynamic compensation reference.

5. The method according to claim 4, characterized in that, The third step is performed when the distance h between the lower surface of the chip and the upper surface of the wafer is 0.2 mm to 0.4 mm.

6. The method according to claim 1, characterized in that, The step of determining the relative tilt of the bonding head relative to the wafer based on the change and calculating the dynamic Abbe error specifically includes: According to Δθ1(t) = θ1(t) - θ BH Determine the angle change of the bonding head, and based on Δθ W (t)=LPF[θ W (t)-θ W0 Determine the thermally induced reference angle drift of the wafer reference plane; where θ1(t) is the real-time angle of the first reflector, θ W (t) represents the real-time angle of the wafer reference plane, θ BH and θ W0 For the third calibration step, LPF represents low-pass filtering; For the same angular component, calculate the relative tilt of the bonding head relative to the wafer reference plane: Δθ Hrel (t)=Δθ1(t)-Δθ W (t); Calculate the dynamic Abbe error based on the pre-calibrated effective Abbe arm: e H (t)=A H sin[Δθ] Hrel (t)];where e H (t) is the lateral position error vector at the bonding interface, A H The pre-calibrated effective Abbe arm coefficient matrix; The effective Abbe arm coefficient matrix is ​​determined based on the structural distance from the equivalent rotation center of the bonding head to the bonding interface, or it is calibrated by applying a known angular displacement to the bonding head and measuring the lateral displacement at the bonding interface.

7. The method according to claim 4, characterized in that, The overall motion angle error of the visual module and the relative angle error between the front and rear ends are determined in the following manner: Calculate the overall angle of the visual module at the first and second marked positions respectively: θ C,M1 =(θ 2M1 +θ 3M1 ) / 2, θ C,M2 =(θ 2M2 +θ 3M2 ) / 2; where θ 2M1 θ 3M1 θ represents the angles of the second and third reflecting mirrors at the first marked position. 2M2 θ 3M2 These are the angles of the second and third reflecting mirrors at the second marked position, respectively. According to Δθ Cam =[θ C,M2 -θ C,M1 ]-[θ WM2 -θ WM1 Determine the overall motion angle error of the vision module; where θ WM1 and θ WM2 These are the angles of the wafer reference plane at the corresponding mark positions; when the vision module moves between the two mark positions, the wafer carrier stage maintains the same mark position posture, or the command posture change of the wafer carrier stage is deducted during calculation; According to δθ Cam =[θ 3M2 -θ 2M2 ]-[θ 3M1 -θ 2M1 The relative angle error between the front and rear ends of the vision module is determined; the overall motion angle error of the vision module and the relative angle error between the front and rear ends are used to correct the visual recognition coordinates.

8. The method according to claim 1, characterized in that, The compensation for visual recognition deviation and bonding head positioning command specifically includes: Establish a unified planar coordinate system, and pre-calibrate the angle-displacement transformation matrix A corresponding to the relative tilt of the bonding head, the overall motion angle of the vision module, the relative angle between the front and rear ends, and the reference angle drift. H A C A D and A W , where A H The pre-calibrated effective Abbe arm coefficient matrix; according to: [ΔX cmd ,ΔY cmd ] T =[ΔX vis,corr ,ΔY vis,corr ] T +A H sin(Δθ) Hrel )+A C sin(Δθ) Cam )+A D ·sin(δθ Cam )+A W sin(Δθ) W Generate bonding head positioning instructions; Where, Δθ Hrel Δθ is the relative tilt of the bonding head relative to the wafer. Cam δθ represents the overall motion angle error of the vision module. Cam Let Δθ be the relative angle error between the front and rear ends. W Let be the reference angle drift, where the superscript T denotes vector transpose, and sin(·) indicates that each component of the angle vector is calculated separately, [ΔX vis,corr ,ΔY vis,corr ] T This is the visual recognition deviation after deducting the measurement deviation caused by the visual module angle error and the reference angle drift.

9. The method according to claim 6, characterized in that, Before calculating the dynamic Abbe error, the method further includes: obtaining the acceleration information of the bonding head during the pressing stroke, and correcting the angle change of the bonding head according to the pre-calibrated dynamic angle response coefficient; The correction is based on Δθ 1corr (t)=Δθ1(t)-Ka·a(t) is executed; where a(t) is the acceleration vector of the bonding head, and Ka is the dynamic angle response coefficient matrix obtained by calibrating the angle response under different acceleration conditions.

10. The method according to claim 8, characterized in that, Also includes: After bonding is completed, obtain the bonding quality inspection results; Based on the residual between the bonding quality test result and the position compensation amount, at least one of the dynamic compensation benchmark, the effective Abbe arm coefficient matrix, and each of the angle-displacement transformation matrices is iteratively updated.

11. A decoupling compensation system for dynamic errors during bonding, characterized in that, include: The bonding head is used to pick up the chip to be bonded and perform the bonding operation. The vision module is used to identify and locate chip markings and wafer markings; Angle measurement unit, used to measure the angle change of the reflecting surface; A first reflecting mirror is disposed on the bonding head; A second reflector is disposed at the front end of the vision module; A third reflecting mirror is disposed at the rear end of the vision module; A wafer is mounted on a support platform of a machine tool, and a preset mirror reflection area on the wafer serves as the wafer reference surface; The control unit, which is signal-connected to the angle measuring unit, is configured to perform the method of any one of claims 1 to 10.

12. The system according to claim 11, characterized in that, The angle measurement unit includes a multi-channel autocollimator or multiple autocollimators, and each measurement channel is used to read the reflected light angle values ​​of the first reflector, the second reflector, the third reflector, and the wafer reference surface, respectively. Alternatively, the angle measurement unit includes an autocollimator and a beam switching mechanism, and the control unit aligns the angles of each reflecting surface to the same compensation time based on the timestamps of each measurement channel.

13. A bonding apparatus, characterized in that, Includes the decoupling compensation system for dynamic errors during the bonding process as described in claim 11 or 12.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 10.

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