Substrate surface self-adaptive contour filling dispensing method based on micro-morphology reconstruction

Abstract

This invention provides an adaptive equal-height leveling dispensing method for substrate surfaces based on micro-morphology reconstruction, relating to the fields of microelectronic packaging and fluid control. It solves the problems of planar fitting's inability to compensate for local morphology deviations and the inability of motion-guided contouring to achieve overall surface leveling. The method establishes a coordinate mapping between a non-contact height sensing unit and a fluid dispensing execution unit. After acquiring the surface height data of the substrate's dispensing area, it processes the data to form three-dimensional morphology data. The three-dimensional morphology data is discretized into multiple micro-elements, obtaining a digital elevation model corresponding to the actual height value of each micro-element. This determines the global highest point height of the substrate's dispensing area, and combines this with a safety offset to obtain the target reference plane height. Based on the difference between the reference and the actual height, the thickness of the adhesive layer to be filled in each micro-element is obtained. After establishing a modulation relationship, dispensing control commands are generated to execute the dispensing operation. This invention achieves the advantage of physically filling substrate depressions and ensuring a consistent final adhesive surface height.

Description

Technical Field

[0001] This invention relates to the fields of semiconductor microelectronic packaging and precision fluid control technology, specifically to an adaptive contour-filling dispensing method for substrate surfaces based on microstructure reconstruction. Background Technology

[0002] In hybrid integrated circuit assembly processes, substrate surface flatness is a key indicator determining chip mounting accuracy and wire bonding quality. Due to high-temperature sintering, material thermal expansion mismatch, and lamination stress release, substrate surfaces often exhibit nonlinear warping, localized depressions, or protrusions. Existing domestic and international research and patent solutions for dispensing processes on such uneven substrates mainly focus on the following three directions, but all have inherent limitations.

[0003] 1. Trajectory Optimization and Follow-up Contouring Technology: As described in the patent document CN120790434A and the literature "Adaptive Processing Trajectory Extraction and System Implementation of Mobile Phone Mid-Frame Based on 2D / 3D Vision," current mainstream solutions focus on using 3D vision or laser scanning to obtain the actual curved surface trajectory of the workpiece, and combining algorithms such as iLQR and YOLOv5 to optimize the motion commands of the robotic arm. The core purpose of this technology is to achieve "high-precision path tracking" or "multi-field trajectory stitching" to ensure that the dispensing head can accurately follow the undulations of the substrate. However, this technology has technical defects. It is essentially a "copy" of the morphology. The adhesive layer after dispensing still retains the original wavy undulations of the substrate, and cannot correct the morphological deviation of the substrate, resulting in tilting after subsequent high-frequency or optical device mounting, which cannot meet the process requirements of absolute level.

[0004] 2. Constant Adhesive Dispensing Compensation and Stabilization Technology: As described in patent documents with publication numbers CN118719452A and CN115254529A, this technology establishes a polynomial model or composite neural network to compensate for adhesive residue, air pressure fluctuations, or response delays, thereby maintaining the long-term stability of adhesive dispensing. Its technical drawback lies in the fact that the control objective is "constant output," meaning achieving consistent deposition per unit length throughout the entire path. This "stabilization" logic cannot meet the differentiated requirements of "more filling in recessed areas and less coating in raised areas" when dealing with non-flat substrates, resulting in devices that still cannot meet absolute level process requirements after bonding and curing.

[0005] 3. Speed ​​Follow-up Control and Defect Detection Technology: As described in patent document CN114505207A, it proposes to dynamically control the dispensing frequency based on the movement speed of the dispensing head relative to the workpiece during five-axis linkage to achieve "equal glue lines" coating. Meanwhile, the literature "Research and Design of Workpiece Dispensing Defect Detection System Based on 3D Vision" also proposes to determine quality defects such as excessive or insufficient glue after dispensing through point cloud segmentation and registration technology. The drawback of these technologies is that the former is a "passive follow-up control," meaning the glue amount changes with speed to maintain uniform coating; the latter only involves "post-treatment quality judgment."

[0006] Currently, there is no technical solution in this field that can proactively allocate flow rate before dispensing based on a "volume-velocity inverse mapping" model to achieve adaptive leveling in a "peak-shaving and valley-filling" manner. Based on existing technical solutions, whether through multi-point planar fitting or existing 3D guided contouring and constant current compensation techniques, there is a lack of a process control scheme that can proactively sense differences in the substrate's microstructure, establish an absolute horizontal plane at the highest point of the dispensing surface, and construct a high-precision horizontal adhesive layer through dynamic speed adjustment. Summary of the Invention

[0007] The purpose of this invention is to address the problems in existing technologies where planar fitting methods struggle to compensate for local topographic deviations, and follow-up contouring methods fail to achieve overall surface leveling. Therefore, this invention proposes an adaptive contour-filling dispensing method for substrate surfaces based on microscopic topographic reconstruction. This invention establishes a digital elevation model of the substrate through high-precision full-field scanning, establishes a reference plane using a "global highest point superimposed with a safety gap" approach, and dynamically modulates the amount of adhesive by utilizing the inverse mapping relationship between fluid stacking volume and motion parameters. This physically fills substrate depressions, ensuring the consistency of the final adhesive surface height.

[0008] The present invention employs the following technical solutions to achieve its objective: An adaptive contour leveling dispensing method for substrate surfaces based on microstructure reconstruction includes the following steps: S1. Perform spatial position calibration on the non-contact height measurement sensing unit and the fluid dispensing execution unit, and establish the mapping relationship between their coordinate systems; S2. The non-contact height sensing unit scans the area of ​​the substrate to be glued, obtains surface height data, and generates three-dimensional topographic data of the substrate surface after data processing. S3. Discretize the three-dimensional topography data into multiple micro-elements and construct a digital elevation model containing the actual height values ​​corresponding to each micro-element. S4. Based on the digital elevation model, determine the global highest point height of the substrate area to be glued, and calculate the target reference plane height by combining the preset safety offset amount. S5. Calculate the difference between the height of the target reference plane and the actual height value of each micro-element to obtain the thickness of the adhesive layer to be filled corresponding to each micro-element, and establish the modulation relationship between the dispensing parameters and the thickness of the adhesive layer to be filled. S6. Generate dispensing control instructions based on the modulation relationship. The dispensing control instructions are used to dynamically adjust the process parameters during the dispensing process. S7. Based on the dispensing control command, synchronously control the motion unit and the fluid dispensing execution unit to perform dispensing operations.

[0009] Specifically, in step S1, the spatial position calibration includes: obtaining the relative position deviation value between the detection center of the non-contact height measuring sensor unit and the physical center of the fluid dispensing execution unit in the horizontal plane, and constructing a coordinate transformation model based on the relative position deviation value; and converting the coordinates of the measurement points collected by the non-contact height measuring sensor unit into the coordinates of the working points of the fluid dispensing execution unit based on the coordinate transformation model.

[0010] Preferably, in step S2, the non-contact height sensing unit uses a grating path to cover the substrate area to be glued; the data processing includes filtering, denoising and smoothing the original surface height data, and removing abnormal data points caused by surface reflection or edge scattering based on a preset threshold, to generate continuous three-dimensional topographic data of the substrate surface after correction.

[0011] Specifically, in step S3, the three-dimensional topography data is divided into a regular grid-like micro-element array according to the preset spatial resolution. Each micro-element corresponds to a local area on the substrate surface, and the actual height value of the center point or average area of ​​the micro-element is stored to form the digital elevation model.

[0012] Specifically, in step S4, the safety offset is a preset minimum thickness threshold for the adhesive layer; the value corresponding to the safety offset is set according to the substrate material, adhesive properties and mounting process requirements; when calculating the height of the target reference plane, the safety offset is added to the height of the global highest point.

[0013] Preferably, in step S5, the dispensing parameters include the horizontal movement speed of the dispensing needle; the modulation relationship is an inverse modulation relationship, including: under the condition that the dispensing valve outflow speed is constant, setting the horizontal movement speed to be inversely proportional to the thickness of the adhesive layer to be filled, that is, when the thickness of the adhesive layer to be filled increases, the horizontal movement speed is reduced, and when the thickness of the adhesive layer to be filled decreases, the horizontal movement speed is increased.

[0014] Specifically, in step S6, the dispensing control command is a continuous variable speed path command; when generating the dispensing control command, a look-ahead control algorithm is used to pre-read the speed requirements of the path segment, calculate the acceleration and deceleration curves, and perform smooth constraint processing on the acceleration and deceleration of the servo motor to suppress the speed change during the motion process to within the preset change threshold.

[0015] Preferably, when the fluid dispensing execution unit adopts a non-contact jet valve, in step S5, the dispensing parameters include the jetting frequency or the valve duty cycle; the modulation relationship is a proportional modulation relationship, including: under the condition that the horizontal movement speed of the nozzle orifice is constant, setting the jetting frequency or the valve duty cycle to be proportional to the thickness of the adhesive layer to be filled, that is, when the thickness of the adhesive layer to be filled increases, the jetting frequency or the valve duty cycle is increased, and when the thickness of the adhesive layer to be filled decreases, the jetting frequency or the valve duty cycle is decreased.

[0016] Specifically, in step S7, the synchronous control includes: during the dispensing operation, according to the dispensing control command, triggering the start and stop sequence of the fluid dispensing execution unit in real time, and synchronously controlling the displacement of the motion unit in the X, Y, and Z axes, so that the dispensing action and the motion trajectory are matched in the time domain.

[0017] Specifically, the non-contact height measurement sensing unit is a line laser profilometer or a structured light 3D scanning sensor; the fluid dispensing execution unit is a piezoelectric dispensing valve with a dispensing needle, or a piezoelectric / pneumatic non-contact jet valve; and the motion unit is a three-axis linear motor platform or a five-axis linkage motion platform.

[0018] In summary, due to the adoption of this technical solution, the beneficial effects of this invention are as follows: This invention achieves a technological breakthrough by "replacing flatness with adhesive," completely changing the passive situation of traditional processes that rely on the flatness of incoming substrates. Through proactive and differentiated adhesive amount compensation, substrates that were originally unqualified due to warping are corrected into qualified components with high-precision horizontal interfaces, significantly reducing the dependence on expensive, high-flatness substrates.

[0019] Compared to traditional manual spot application or simple segmented application, this invention is based on a high-density discretized micro-element model, which enables independent inversion and control of the amount of adhesive in each tiny region. In practical applications, the side length of the micro-element can be determined to a scale of 0.1 mm, allowing for extremely fine control of the particle size.

[0020] This invention forces the superposition of a safety bias amount at the "global highest point" of the adhesive application surface as a benchmark, eliminating the risk of the needle hitting the substrate protrusion during high-speed close-up movement from the logic layer, effectively protecting the needle and high-value products.

[0021] This invention does not depend on the specific deformation law of the substrate. Whether it is a regular bow-shaped warp or a disordered wave-shaped undulation, this invention performs adaptive processing based on its full-field height scan, without the need to write a separate control program for each deformation feature. Attached Figure Description

[0022] The present invention is described in detail with reference to the following figures, which include four figures as follows: Figure 1 This is a schematic diagram illustrating the overall process of the adaptive equal-height leveling dispensing method for substrate surface according to the present invention. Figure 2 This is a schematic diagram comparing the modulation relationship between the dispensing needle movement speed and the thickness of the adhesive layer to be filled in the method of the present invention; Figure 3 This is a comparative schematic diagram showing the working state of the dispensing needle when passing through the recessed area and the raised area of ​​the substrate in the method of the present invention. Figure 4 This is a schematic diagram comparing the effects of the method of the present invention and the follow-up contouring method in the prior art on the dispensing cross section. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The parts of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] Example 1 An adaptive contour leveling dispensing method for substrate surfaces based on microstructure reconstruction. Figure 1 The overall process of this method is briefly described below and can be viewed concurrently; the key steps of this method can be summarized as follows: S1. Perform spatial position calibration on the non-contact height measurement sensing unit and the fluid dispensing execution unit, and establish the mapping relationship between their coordinate systems; S2. Scan the substrate area to be glued using a non-contact height measurement sensor unit to obtain surface height data, and generate three-dimensional topographic data of the substrate surface after data processing. S3. Discretize the three-dimensional topographic data into multiple micro-elements and construct a digital elevation model containing the actual height values ​​corresponding to each micro-element. S4. Based on the digital elevation model, determine the global highest point height of the substrate area to be glued, and calculate the target reference plane height by combining the preset safety offset. S5. Calculate the difference between the height of the target reference plane and the actual height of each micro-element to obtain the thickness of the adhesive layer to be filled corresponding to each micro-element, and establish the modulation relationship between the dispensing parameters and the thickness of the adhesive layer to be filled. S6. Generate dispensing control instructions based on modulation relationship. The dispensing control instructions are used to dynamically adjust process parameters during the dispensing process. S7. Based on dispensing control commands, synchronously control the motion unit and the fluid dispensing execution unit to perform dispensing operations.

[0026] This embodiment will provide a detailed and optimized description of the details and contents of each step in the method.

[0027] This embodiment relies on an integrated automated dispensing system comprised of a non-contact height sensing unit, a fluid dispensing execution unit, and a motion unit. The non-contact height sensing unit is used to non-destructively acquire microscopic three-dimensional topographic data of the substrate surface; specifically, a line laser profilometer or a structured light 3D scanning sensor can be used. The line laser profilometer, based on the principle of laser triangulation, calculates the height coordinates in real time by analyzing the deformation profile of the projected laser line on the surface. The structured light 3D scanning sensor achieves full-field 3D reconstruction by projecting an coded grating pattern and analyzing the stripe deformation captured by the camera.

[0028] The fluid dispensing actuator is responsible for the precise output and deposition control of the adhesive. It can be composed of a piezoelectric dispensing valve and a precision dispensing needle. The piezoelectric dispensing valve uses the inverse piezoelectric effect of piezoelectric ceramics to drive the valve needle to open and close, achieving accurate control of the adhesive dispensing volume. The motion unit is a high-precision positioning platform, which can be configured as a three-axis linear motor platform or a five-axis linkage motion platform. The three-axis linear motor platform provides three mutually perpendicular linear motion degrees of freedom (X, Y, Z), while the five-axis linkage motion platform integrates A and B rotary axes on the basis of the three axes, making it suitable for trajectory tracking of substrates with spatial curvature.

[0029] In this embodiment, the motion unit uses a three-axis linear motor platform, the height measurement sensing unit uses a high-resolution line laser profile sensor with a vertical repeatability better than 1 micrometer, and the fluid dispensing execution unit uses a combination of a high-frequency response piezoelectric dispensing valve and a precision dispensing needle with controllable inner diameter. The workpiece to be processed is a low-temperature co-fired ceramic (LTCC) substrate commonly used in the field of radio frequency microsystems. The LTCC substrate is a multilayer interconnected ceramic substrate formed by stacking and laminating glass-ceramic composite green ceramic tapes and then co-firing them at a low temperature of about 850°C. Due to uneven thermal shrinkage of the material and release of interlayer stress during the sintering process, irregular micro-undulations are easily formed on the surface. In this embodiment, the maximum height difference of the area to be dispensed on the LTCC substrate was measured to be about 50 micrometers.

[0030] In step S1 of this embodiment, spatial position calibration is performed, including: obtaining the relative position deviation value between the detection center of the non-contact height measuring sensor unit and the physical center of the fluid dispensing execution unit in the horizontal plane, and constructing a coordinate transformation model based on the relative position deviation value; based on the coordinate transformation model, converting the coordinates of the measurement point collected by the non-contact height measuring sensor unit into the coordinates of the working point of the fluid dispensing execution unit.

[0031] Spatial position calibration is used to establish the spatial geometric correspondence between the non-contact height measurement sensing unit and the fluid dispensing execution unit. The detection center here specifically refers to the effective spatial reference point when the height measurement sensing unit performs height sampling, i.e., the theoretical origin of the intersection of the laser line projection and the camera's imaging field of view in the line laser profilometer; the physical center is the geometric center point of the dispensing needle tip, i.e., the physical positioning reference for the actual output of the adhesive. The calibration operation can be performed using an optical planar calibration plate with pre-set precision cross-shaped scribe lines on its surface. This calibration plate is firmly fixed to the worktable of the motion platform by vacuum adsorption or mechanical clamps, and the intersection of its scribe lines serves as a highly repeatable spatial reference feature.

[0032] The control system first drives the motion unit, causing the non-contact height-measuring sensor unit to scan the calibration plate marking area along a preset path. A built-in algorithm identifies the two-dimensional coordinates of the center point of the crosshair marking in its local coordinate system. Then, the control system slowly moves the dispensing needle downwards along the Z-axis, using a force sensor or visual feedback to confirm that the needle tip lightly touches the same marking center point, and simultaneously records the precise position coordinates of the needle tip in the global coordinate system of the motion platform. Based on the coordinate difference of the same physical reference point in the coordinate systems of the two sub-units (the non-contact height-measuring sensor unit and the fluid dispensing execution unit), the system calculates the relative position deviation of the detection center relative to the physical center in the X and Y horizontal planes. This deviation includes a linear offset component and a small rotational angle component. Based on this deviation, the system constructs a two-dimensional affine transformation model as the coordinate transformation model, which is composed of a combination of translation and rotation matrices.

[0033] In the subsequent substrate dispensing process, the original coordinates of all surface measurement points collected by the non-contact height measurement sensing unit are input into the coordinate transformation model in real time. After calculation, the transformed work point coordinates are output. These work point coordinates are directly used to drive the motion unit to accurately position the fluid dispensing execution unit to the corresponding spatial position.

[0034] In step S2 of this embodiment, the non-contact height sensing unit uses a grating path to cover the substrate area to be glued; the data processing includes filtering, denoising and smoothing the original surface height data, and removing abnormal data points caused by surface reflection or edge scattering based on a preset threshold, generating continuous three-dimensional topographic data of the substrate surface after correction.

[0035] The motion unit drives the non-contact height measurement sensor to perform a full-coverage scan of the substrate's adhesive application area along a preset grating-type scanning path. The grating-type scanning path refers to completing a single-line linear scan at a constant speed in the X-axis direction, then stepping a set interval along the Y-axis direction, and then performing the next line scan in the opposite direction along the X-axis, repeating this cycle to form a dense parallel scanning trajectory; the scanning step interval and single-line scanning speed can both be set according to the accuracy required for actual topographic analysis.

[0036] During the scanning process, a line laser profilometer continuously projects a linear laser line onto the substrate surface. A high-resolution industrial camera simultaneously captures images of the deformation caused by surface undulations along the laser line. Based on the principle of triangulation, the three-dimensional coordinates of each sampling point on the laser line are calculated in real time. These coordinates are accumulated line by line to form the original three-dimensional point cloud dataset, which constitutes the original surface height data. This original data will include noise points and outliers caused by localized high reflectivity areas on the substrate surface, tiny particle attachments, or scattering from geometric edges.

[0037] The raw height data needs to undergo a multi-stage processing procedure for correction. First, a median filtering algorithm is used to perform preliminary denoising on the point cloud data to eliminate isolated noise points. Then, a sliding window Gaussian smoothing algorithm is applied to smooth the data, with the window size set to 5×5 neighborhood data points. Subsequently, outlier identification and removal are performed. Specifically, the average height difference between each data point and its eight neighboring points is calculated. If the absolute value of the difference exceeds a preset outlier threshold, the point is determined to be outlier data and removed. For the data gaps caused by removal, bilinear interpolation can be used to fill in the gaps and restore data continuity.

[0038] The data processed as described above can be used to form a continuous three-dimensional mesh surface model through triangulation, generating regular meshed digital three-dimensional topographic data. This data is then stored in the form of a two-dimensional matrix, where each element corresponds to the precise height value of a sampling location on the substrate surface. The mesh node spacing is consistent with the scanning step spacing, fully preserving the geometric features of the substrate surface's micro-undulations, providing a high-fidelity data foundation for subsequent elevation model construction.

[0039] In step S3 of this embodiment, the three-dimensional topography data is divided into a regular grid-like micro-element array according to the preset spatial resolution. Each micro-element corresponds to a local area on the substrate surface, and the actual height value of the center point or average area of ​​the micro-element is stored to form a digital elevation model.

[0040] The corrected three-dimensional topography data generated in step S2 needs to be projected onto the two-dimensional plane coordinate system where the substrate is located, and in step S3, regular mesh division is performed according to the spatial resolution preset by the dispensing process.

[0041] In this embodiment, the spatial resolution can be set to a 20×20 micrometer square unit, which differs from the resolution of the gridded sampling positions in step S2. The spatial resolution of the dispensing process can be determined by comprehensively considering the inner diameter of the dispensing needle, the rheological properties of the adhesive, and the requirements for leveling accuracy. Each square unit is defined as a discretized micro-element. The system extracts the height values ​​of all effective sampling points within the coverage area of ​​this micro-element and calculates the arithmetic mean as the actual height value of the micro-element. The constructed digital elevation model is also stored in the form of a two-dimensional matrix. The matrix row and column indices correspond to the coordinate positions of the micro-element on the substrate plane, and the matrix element values ​​are the actual height values ​​stored for each micro-element.

[0042] In the digital elevation model, the regular grid micro-element array adopts an equally spaced orthogonal grid division. Each micro-element is an independent process control unit. Its height data directly serves the subsequent calculation of the micro-element adhesive layer thickness and the dynamic modulation of dispensing parameters. The regular arrangement characteristics facilitate mapping with the dispensing path and the generation of real-time control commands, providing a structured data foundation for achieving "peak shaving and valley filling" leveling.

[0043] In step S4 of this embodiment, the safety offset is a preset minimum thickness threshold of the adhesive layer; the value corresponding to the safety offset is set according to the substrate material, adhesive properties and mounting process requirements; when calculating the height of the target reference plane, the safety offset is added to the height of the global highest point.

[0044] The system iterates through all the actual height values ​​stored in the digital elevation model constructed in step S3, and identifies the global highest point height value within the substrate's adhesive application area through numerical comparison calculations. The safety offset is a key process parameter in this embodiment, physically defined as the minimum thickness threshold that the cured adhesive layer must maintain at the highest point of the substrate. The specific value of this parameter needs to be set by comprehensively considering the substrate material characteristics (surface micro-roughness and thermomechanical stability of the LTCC substrate), adhesive material properties (including viscosity, surface tension, and curing shrinkage), and the subsequent chip mounting process's requirements for the adhesive layer thickness.

[0045] This embodiment addresses the specific process conditions for the LTCC substrate and epoxy conductive adhesive in the RF microsystem. After multiple rounds of process verification, the safety offset was set to 10 micrometers. The target reference plane height is calculated by algebraically adding the global highest point height value to the safety offset. The resulting reference plane is defined as a virtual horizontal reference plane located above the substrate surface and parallel to the substrate mounting reference plane. Its height value serves as a unified spatial reference for subsequent calculations of the adhesive layer thickness of each micro-element and dynamic modulation of dispensing parameters.

[0046] In step S5 of this embodiment, the dispensing parameters include the horizontal movement speed of the dispensing needle. The modulation relationship is an inverse proportional modulation relationship, which can be referred to... Figure 2 The illustration includes: under the condition that the dispensing valve flow rate is constant, the horizontal movement speed is set to be inversely proportional to the thickness of the adhesive layer to be filled; that is, the horizontal movement speed is decreased when the thickness of the adhesive layer to be filled increases, and the horizontal movement speed is increased when the thickness of the adhesive layer to be filled decreases. The thickness of the adhesive layer to be filled can be simply understood as two working zone states of the substrate, i.e. Figure 3 The horizontal movement speeds shown in the diagrams for working in the concave area (State A) and the convex area (State B) are slow speed (V1) and fast speed (V2), respectively.

[0047] In this embodiment, the system traverses all micro-elements in the digital elevation model, calculating the algebraic difference between the target reference plane height and the actual height of each micro-element. This difference represents the required adhesive layer thickness for the corresponding micro-element position. Under constant process parameters such as the dispensing valve's driving air pressure, valve opening time, and adhesive supply pressure, the dispensing valve maintains a stable adhesive outflow rate, meaning the volume of adhesive flowing out through the dispensing needle per unit time is a fixed value. Based on the principle of fluid volume conservation, this embodiment establishes an inverse proportional modulation relationship between the horizontal movement speed of the dispensing needle and the thickness of the adhesive layer to be filled. This relationship can be constrained by process constants, which are determined through calibration experiments using adhesive viscosity, dispensing needle inner diameter, and preset unit area adhesive layer volume parameters.

[0048] Under the specific parameter settings of this embodiment, when the calculated thickness of the adhesive layer to be filled for a certain micro-element is 50 micrometers, the system generates a horizontal movement speed command of 5 millimeters per second based on the inverse modulation relationship; when the thickness of the adhesive layer to be filled for another micro-element is 10 micrometers, a horizontal movement speed command of 12.5 millimeters per second is generated. The system organizes the movement speed values ​​corresponding to all micro-elements according to their spatial coordinate order, and preferably uses a cubic spline interpolation algorithm to smoothly connect the discrete speed nodes, generating a continuous speed planning curve corresponding to the dispensing path. This speed planning curve, as the core component of the dispensing control command, ensures that the motion unit adjusts the horizontal movement speed in real time according to the local topography of the substrate during its movement, realizing micro-element-based control of the adhesive deposition amount.

[0049] In step S6 of this embodiment, the dispensing control command is specifically a continuous variable speed path command. When generating the dispensing control command, a look-ahead control algorithm is used to pre-read the speed requirements of the path segment, calculate the acceleration and deceleration curves, and perform smooth constraint processing on the acceleration and deceleration of the servo motor to suppress the speed change during the motion process to within the preset change threshold.

[0050] The control system integrates the continuous speed planning curve generated in step S5 with the substrate dispensing path to form a continuous variable speed path command containing position coordinates and corresponding motion speeds. During the command generation stage, a look-ahead control algorithm is preferably used to pre-read the speed demand sequence of subsequent path segments in real time. Based on the servo motor dynamics model, an S-shaped acceleration / deceleration curve that satisfies acceleration continuity is calculated, and smoothing constraints are applied to acceleration and deceleration to limit the rate of speed change within a preset threshold. This process effectively suppresses mechanical vibration and inertial impact caused by sudden speed jumps during motion, ensuring smooth speed changes along the path and providing a stable foundation for precise control of adhesive deposition.

[0051] In step S7 of this embodiment, the synchronous control includes: during the dispensing operation, according to the dispensing control command, the start and stop sequence of the fluid dispensing execution unit is triggered in real time, and the displacement of the motion unit in the X, Y, and Z axes is synchronously adjusted so that the dispensing action and the motion trajectory are matched in the time domain.

[0052] The control system outputs real-time position and speed command sequences along the X, Y, and Z axes based on continuously variable speed path commands. Simultaneously, it sends pulse trigger signals synchronized with the motion trajectory to the piezoelectric dispensing valve drive circuit. The opening and closing sequence of the dispensing valve is precisely defined by the path's micro-element boundaries, ensuring that the adhesive is deposited only within the planned area. The Z-axis direction can dynamically fine-tune the needle-to-board gap based on the height value of the corresponding position in the digital elevation model, maintaining a safe working distance between the dispensing needle and the substrate surface to prevent physical interference during movement.

[0053] After the dispensing process is completed, the adhesive deposited on the substrate surface undergoes a natural micro-leveling process under the combined action of surface tension and gravity. The adhesive molecules minimize surface energy through a dynamic balance between cohesive and adhesive forces. After standing for several seconds to tens of seconds, the surface height of the adhesive layer approaches the target reference plane set in step S4. (See also...) Figure 4 The comparison shows that the existing follow-up contouring method may result in uneven glue surface after dispensing, while this embodiment can well conform to its absolute reference plane.

[0054] In this embodiment, after the adhesive has fully cured, in order to verify the dispensing effect, a non-contact secondary scan of the upper surface of the adhesive layer is performed using the same line laser profilometer as in step S2 to reconstruct the three-dimensional morphology of the cured surface and calculate the flatness parameters. The measured data show that the overall flatness error of the upper surface of the adhesive layer can be stably controlled within 10 micrometers, effectively correcting the original 50-micrometer morphological difference of the substrate to the flatness tolerance range required by the RF microsystem chip mounting process.

[0055] Example 2 Based on Example 1, this example describes another scenario in step S5 of the method.

[0056] In this embodiment, when the fluid dispensing execution unit no longer uses a combination of a high-frequency response piezoelectric dispensing valve and a precision dispensing needle with controllable inner diameter, but instead uses a non-contact jet valve, the dispensing parameters in step S5 include the jetting frequency or the valve duty cycle. The modulation relationship is also a proportional modulation relationship, including: under the condition that the horizontal movement speed of the nozzle orifice is constant, setting the jetting frequency or the valve duty cycle to be proportional to the thickness of the adhesive layer to be filled, that is, increasing the jetting frequency or increasing the valve duty cycle when the thickness of the adhesive layer to be filled increases, and decreasing the jetting frequency or decreasing the valve duty cycle when the thickness of the adhesive layer to be filled decreases.

[0057] The non-contact injection valve uses a piezoelectric or pneumatic actuation structure. It generates instantaneous pressure impact by driving an internal striking pin with a high-frequency electrical signal or compressed air pulse, causing the adhesive to be ejected from the nozzle orifice in the form of discrete microdroplets, thus achieving the adhesive transfer process. The injection parameters are adjustable. The injection frequency is defined as the number of injection actions completed per unit time, measured in Hertz (Hz). The valve duty cycle refers to the ratio of the valve opening time to the total cycle time within a single injection cycle in pulse width modulation control mode.

[0058] In step S5 of this embodiment, the system sets the horizontal movement speed of the nozzle orifice to a constant value, and adjusts the dispensing parameters to the spray frequency or valve duty cycle. Based on the principle of fluid volume conservation, a proportional modulation relationship is established between the spray frequency or valve duty cycle and the thickness of the adhesive layer to be filled: when the thickness of the adhesive layer to be filled increases, the system increases the spray frequency or valve duty cycle; when the thickness of the adhesive layer to be filled decreases, the system decreases the spray frequency or valve duty cycle. This relationship is determined by a proportionality coefficient through calibration experiments, which comprehensively considers the adhesive viscosity, surface tension, nozzle orifice diameter, and single drop volume parameters.

[0059] The system organizes the spraying parameter values ​​corresponding to each micro-element in spatial coordinate order and merges them with the path coordinate data of constant motion speed, thus generating a dispensing control command that includes position sequence, constant motion speed and dynamic spraying parameter sequence.

[0060] In subsequent steps, the motion unit moves along the planned path at a constant speed according to the instruction, while the fluid dispensing execution unit synchronously receives the spraying parameter instructions and adjusts the frequency or pulse width parameters of the drive signal in real time to precisely control the number of adhesive droplets sprayed per unit path length or the amount of adhesive sprayed in a single spray. This embodiment adapts to the dispensing process scenario of the corresponding equipment by changing the type of dispensing execution unit and the core control parameters, while maintaining the overall logical framework of the method, achieving the same volume filling control effect.

Claims

1. A substrate surface adaptive contour leveling dispensing method based on microstructure reconstruction, characterized in that, Includes the following steps: S1. Perform spatial position calibration on the non-contact height measurement sensing unit and the fluid dispensing execution unit, and establish the mapping relationship between their coordinate systems; S2. The non-contact height sensing unit scans the area of ​​the substrate to be glued, obtains surface height data, and generates three-dimensional topographic data of the substrate surface after data processing. S3. Discretize the three-dimensional topography data into multiple micro-elements and construct a digital elevation model containing the actual height values ​​corresponding to each micro-element. S4. Based on the digital elevation model, determine the global highest point height of the substrate area to be glued, and calculate the target reference plane height by combining the preset safety offset amount. S5. Calculate the difference between the height of the target reference plane and the actual height value of each micro-element to obtain the thickness of the adhesive layer to be filled corresponding to each micro-element, and establish the modulation relationship between the dispensing parameters and the thickness of the adhesive layer to be filled. S6. Generate dispensing control instructions based on the modulation relationship. The dispensing control instructions are used to dynamically adjust the process parameters during the dispensing process. S7. Based on the dispensing control command, synchronously control the motion unit and the fluid dispensing execution unit to perform dispensing operations.

2. The substrate surface adaptive equal-height leveling dispensing method according to claim 1, characterized in that, In step S1, the spatial position calibration includes: obtaining the relative position deviation value between the detection center of the non-contact height measuring sensor unit and the physical center of the fluid dispensing execution unit in the horizontal plane, and constructing a coordinate transformation model based on the relative position deviation value; and converting the coordinates of the measurement points collected by the non-contact height measuring sensor unit into the coordinates of the working points of the fluid dispensing execution unit based on the coordinate transformation model.

3. The substrate surface adaptive equal-height leveling dispensing method according to claim 1, characterized in that: In step S2, the non-contact height sensing unit uses a grating path to cover the area of ​​the substrate to be glued; the data processing includes filtering, denoising and smoothing the original surface height data, and removing abnormal data points based on a preset threshold to generate continuous three-dimensional topographic data of the substrate surface after correction.

4. The substrate surface adaptive equal-height leveling dispensing method according to claim 1, characterized in that: In step S3, the three-dimensional topography data is divided into a regular grid-like micro-element array according to the preset spatial resolution. Each micro-element corresponds to a local area on the substrate surface, and the actual height value of the center point or average area of ​​the micro-element is stored to form the digital elevation model.

5. The substrate surface adaptive equal-height leveling dispensing method according to claim 1, characterized in that: In step S4, the safety offset is a preset minimum thickness threshold of the adhesive layer; the value corresponding to the safety offset is set according to the substrate material, adhesive properties and mounting process requirements; when calculating the height of the target reference plane, the safety offset is added to the height of the global highest point.

6. The substrate surface adaptive equal-height leveling dispensing method according to claim 1, characterized in that: In step S5, the dispensing parameters include the horizontal movement speed of the dispensing needle; The modulation relationship is an inverse modulation relationship, including: under the condition that the dispensing valve outflow speed is constant, the horizontal movement speed is set to be inversely proportional to the thickness of the adhesive layer to be filled, that is, when the thickness of the adhesive layer to be filled increases, the horizontal movement speed is reduced, and when the thickness of the adhesive layer to be filled decreases, the horizontal movement speed is increased.

7. The substrate surface adaptive equal-height leveling dispensing method according to claim 6, characterized in that: In step S6, the dispensing control command is a continuous variable speed path command; when generating the dispensing control command, a look-ahead control algorithm is used to pre-read the speed requirements of the path segment, calculate the acceleration and deceleration curves, and perform smooth constraint processing on the acceleration and deceleration of the servo motor to suppress the speed change during the motion process to within the preset change threshold.

8. The substrate surface adaptive equal-height leveling dispensing method according to claim 1, characterized in that: When the fluid dispensing execution unit uses a non-contact jet valve, in step S5, the dispensing parameters include the jetting frequency or the valve duty cycle. The modulation relationship is a proportional modulation relationship, including: under the condition that the horizontal movement speed of the nozzle orifice is constant, setting the injection frequency or the valve opening duty cycle to be proportional to the thickness of the adhesive layer to be filled, that is, when the thickness of the adhesive layer to be filled increases, the injection frequency or the valve opening duty cycle is increased; when the thickness of the adhesive layer to be filled decreases, the injection frequency or the valve opening duty cycle is decreased.

9. The substrate surface adaptive equal-height leveling dispensing method according to claim 1, characterized in that, In step S7, the synchronous control includes: during the dispensing operation, according to the dispensing control command, triggering the start and stop sequence of the fluid dispensing execution unit in real time, and synchronously controlling the displacement of the motion unit in the X, Y, and Z axes, so that the dispensing action and the motion trajectory are matched in the time domain.

10. The substrate surface adaptive equal-height leveling dispensing method according to claim 1, characterized in that: The non-contact height measurement sensing unit is a line laser profilometer or a structured light 3D scanning sensor; the fluid dispensing execution unit is a piezoelectric dispensing valve with a dispensing needle, or a piezoelectric / pneumatic non-contact jet valve; the motion unit is a three-axis linear motor platform or a five-axis linkage motion platform.

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