A flip chip welding protection structure

Abstract

The present invention relates to the field of chip welding technology, specifically a flip-chip welding protection structure, comprising: a protective layer, arranged on the outside of the chip to be welded; a driving component, used to drive the protective layer to fit on the chip to be welded; a positioning component, used to position the chip to be welded and the protective layer, so that the chip to be welded and the protective layer are relatively positioned; a detection module, used to detect the flatness and protective ability of the protective layer; an auxiliary replacement component, used to assist in replacing the protective layer when the protective ability of the protective layer is lower than a preset index. The present invention detects the protective layer so that the protective layer can form all-round protection for the chip during the welding process. Through the cooperation of the winding component and the auxiliary replacement component, not only can the protective layer be quickly fitted on the chip, but also the protective layer can be replaced in time when the protective ability of the protective layer is insufficient, without affecting the welding efficiency, while improving the protection effect, ensuring the welding quality, and reducing the protection cost.

Description

Technical Field

[0001] The present invention relates to the technical field of chip welding, in particular to a flip chip welding protection structure. Background Art

[0002] As an advanced chip packaging interconnect technology, flip chip has become a mainstream choice for modern electronic packaging (particularly in high-performance computing, communications, sensors, image processing, and other fields) due to its significant advantages such as high density, high performance, and miniaturization. In flip chip packaging, the active surface of the chip (containing input / output pads and circuitry) is turned downward, and microbumps (or solder bumps) distributed on the chip surface directly connect electrically and mechanically to corresponding pads on the substrate or printed circuit board (PCB).

[0003] However, existing flip-chip processes still suffer from inadequate chip protection, such as solder spattering onto sensitive chip areas and solder overflowing or climbing along chip edges. Particularly during micro-bump plating, the lack of reliable protective measures or the failure to promptly clean and replace protective materials can lead to solder deposits in non-soldering areas or along chip edges. These protective failures directly lead to irreversible chip electrical shorts, physical damage, loss of functionality, chemical contamination, and solder bridging and voiding, severely limiting the yield improvement and potential of flip-chip packaging in high-density, high-reliability applications. Replacing protective materials with every weld not only increases material costs but also reduces welding efficiency, hindering the long-term, efficient operation of the welding process. Summary of the Invention

[0004] Based on this, it is necessary to propose a flip chip welding protection structure to address the above problems.

[0005] The present invention is implemented through the following technical solutions: A flip chip welding protection structure includes:

[0006] A protective layer is provided on the outside of the chip to be welded;

[0007] A driving component, used for driving the protective layer to fit onto the chip to be welded;

[0008] A positioning component, used for positioning the chip to be welded and the protective layer so that the chip to be welded and the protective layer are positioned relative to each other;

[0009] A detection module, used to detect the flatness and protective capability of the protective layer;

[0010] An auxiliary replacement component is used to assist in replacing the protective layer when the protective ability of the protective layer is lower than a preset index.

[0011] The above-mentioned flip-chip welding protection structure detects the protective layer so that the protective layer can provide all-round protection for the chip during the welding process. Through the cooperation of the winding component and the auxiliary replacement component, not only can the protective layer be quickly attached to the chip, but also the protective layer can be replaced in time when the protective capacity of the protective layer is insufficient. The replacement and attachment processes can be realized during the movement of the chip without affecting the welding efficiency. At the same time, it improves the protection effect, ensures the welding quality, and reduces the protection cost.

[0012] Furthermore, a plurality of through holes are formed on the protective layer, and the through holes have the same shape, size and spacing as the welding areas on the chips to be welded.

[0013] Furthermore, the driving component includes a transverse drive and a winding component; the transverse drive is installed on the welding device to drive the protective layer to move laterally; the winding component is installed in the welding device; the winding component is used to wind up the protective layer so that the protective layer fits on the chip to be welded.

[0014] Furthermore, the winding assembly includes a unwinding drum, a winding drum, a motor, and a linkage; the unwinding drum and the winding drum are both installed in the welding device; the output end of the motor is fixedly connected to the winding drum for driving the winding drum to rotate; the linkage is installed between the unwinding drum and the winding drum.

[0015] Furthermore, the positioning assembly includes an imaging unit, a substrate positioning unit and a protective layer positioning unit; the imaging unit is used to obtain an image of the chip to be welded, an image of the welding substrate and an image of the protective layer, and to identify the chip position; the substrate positioning unit includes a positioning block, the positioning block is an irregular shape, and a positioning groove matching the positioning block is provided on the clamping device, and the clamping device is used to clamp the welding substrate; the protective layer positioning unit includes a plurality of positioning rods, the positioning rods are fixedly connected to the welding device, and the bottom end of the positioning rod is set to a spherical shape, and the protective layer is provided with a plurality of positioning holes matching the positioning rods.

[0016] Furthermore, the detection module includes a flatness recognition unit and a protection capability recognition unit; the flatness recognition unit is used to recognize the flatness of the front surface of the protective layer; and the protection capability recognition unit is used to recognize the protection capability of the protective layer based on the protective layer image.

[0017] Furthermore, the recognition process of the flatness recognition unit includes:

[0018] acquiring a planar frontal image of the protective layer when the protective layer is in a stretched state;

[0019] Performing grayscale processing on the planar front image, setting a plurality of first acquisition points in the planar front image after the grayscale processing, and acquiring the brightness of each first acquisition point;

[0020] The first smoothness is calculated using the brightness-smoothness fitting method;

[0021] Acquire a curved surface front image and a curved surface side image of the protective layer when the protective layer is in a curved state;

[0022] Performing three-dimensional modeling based on the curved surface front image and the curved surface side image to obtain a three-dimensional image of the protective layer;

[0023] Setting a plurality of second acquisition points in the curved surface front image, and acquiring the brightness of each second acquisition point;

[0024] Marking the three-dimensional coordinates of each second acquisition point in the three-dimensional image of the protection layer, and correcting the brightness of the second acquisition point according to the normal vector of the tangent plane where the three-dimensional coordinates are located;

[0025] The second smoothness is calculated using the brightness-smoothness fitting method;

[0026] Perform weighted operation on the first flatness and the second flatness to obtain the comprehensive flatness.

[0027] Furthermore, the brightness-flatness fitting method includes:

[0028] Calculate the ideal brightness based on the brightness of multiple acquisition points;

[0029] Calculate the brightness gradient and brightness curvature of each acquisition point;

[0030] The acquisition point with the largest brightness gradient and the acquisition point with the largest brightness curvature are selected, and the flatness is calculated by combining the two acquisition points with the largest difference from the ideal brightness.

[0031] Furthermore, the identification process of the protection capability identification unit includes:

[0032] Preprocessing the protection layer image;

[0033] Build an image recognition model based on neural network;

[0034] Using a historically collected set of protection layer images to train the image recognition model;

[0035] The pre-processed protective layer image is input into the trained image recognition model to output the protective capability of the protective layer.

[0036] Furthermore, the auxiliary replacement assembly includes a lock, a limiter and an adjustment cylinder; the adjustment cylinder is elastically installed in the welding device, and the adjustment cylinder is arranged parallel to the unwinding cylinder and the winding cylinder; the lock is installed on the unwinding cylinder for locking the unwinding cylinder; the limiter is arranged on the outside of the winding cylinder, and the winding cylinder is limited by extending one end of the limiter into the through hole.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] A flip-chip welding protection structure of the present invention detects the protective layer so that the protective layer can provide all-round protection for the chip during the welding process. Through the cooperation of the winding component and the auxiliary replacement component, not only can the protective layer be quickly attached to the chip, but the protective layer can also be replaced in time when the protective capacity of the protective layer is insufficient. The replacement and attachment processes can be achieved during the movement of the chip without affecting the welding efficiency. At the same time, the protection effect is improved, the welding quality is guaranteed, and the protection cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the three-dimensional structure of a flip chip welding protection structure in Example 1 of the present invention;

[0040] Figure 2 for Figure 1 Schematic diagram of the three-dimensional structure of the winding component;

[0041] Figure 3 for Figure 2 Another three-dimensional structural schematic diagram of the winding assembly;

[0042] Figure 4 for Figure 1 Schematic diagram of the partial three-dimensional structure of the flip chip welding protection structure;

[0043] Figure 5 for Figure 4 Schematic diagram of the three-dimensional structure when the protective layer is removed;

[0044] Figure 6 for Figure 4 Schematic diagram of the top view structure;

[0045] Figure 7 for Figure 6 Schematic diagram of the cross-section structure along the BB direction;

[0046] Figure 8 for Figure 7 Schematic diagram of the structure in the replacement state.

[0047] In the figure: 1. Protective layer; 11. Through hole; 12. Positioning hole; 2. Driving assembly; 22. Rewinding assembly; 221. Unwinding drum; 222. Rewinding drum; 223. Motor; 224. Linkage; 5. Auxiliary replacement assembly; 51. Lock; 52. Limiter; 53. Adjusting cylinder; 10. Welding device; 20. Chip to be welded. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component. When a component is considered to be "fixed to" another component, it may be directly fixed to the other component or there may be a central component.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0051] Example 1: Please refer to Figures 1-8 This embodiment provides a flip chip welding protection structure, including: a protection layer 1, a driving component 2, a positioning component, a detection module and an auxiliary replacement component 5.

[0052] The protective layer 1 is disposed on the outside of the chip 20 to be soldered. The protective layer 1 is made of a high-temperature-resistant flexible material, such as polyimide, polytetrafluoroethylene, liquid crystal polymer, etc. In this embodiment, the protective layer 1 is made of polyimide material, which can withstand high temperatures of 200-300°C for a long time, has stronger instantaneous high-temperature resistance, and can provide strong and effective protection for non-soldering areas on the chip. The single-piece protective layer 1 is a rectangular sheet as a whole, and the positions where the protective layers 1 are connected are provided with cutting notches for easy cutting. The protective layer 1 is rolled up on a reel as a whole and can be pulled out from the reel in sequence for use.

[0053] The protective layer 1 is provided with a plurality of through holes 11. The through holes 11 are consistent in shape, size, and spacing with the soldering areas on the chip 20 to be soldered. The shape and position of the through holes 11 on the protective layer 1 can be set according to the chip 20 to be soldered. When soldering chips of different specifications, the corresponding protective layer 1 can be freely selected. For example, the protective layer 1 roll can be directly replaced on the reel, which is convenient and suitable for soldering chips of various sizes.

[0054] The driving assembly 2 is used to drive the protective layer 1 to fit on the chip to be welded 20. The driving assembly 2 includes a transverse drive and a winding assembly 22; the transverse drive is installed on the welding device 10 and is used to drive the protective layer 1 to move laterally; the winding assembly 22 is installed in the welding device 10; the winding assembly 22 is used to wind up the protective layer 1 so that the protective layer 1 fits on the chip to be welded 20. Specifically, a mounting groove is opened in the welding device 10, and a mounting bracket is slidably connected in the mounting groove, and the winding assembly 22 is installed on the mounting bracket. The transverse drive can drive the winding assembly 22 to move as a whole, so that the protective layer 1 moves to or away from the chip to be welded 20 directly below the chip to be welded 20.

[0055] In this embodiment, the transverse actuator utilizes a screw drive mechanism comprising a drive motor, a screw, and a nut. The drive motor is fixedly mounted within a mounting slot. One end of the screw is fixedly connected to the drive motor, while the other end is rotatably connected within the mounting slot. The nut is threadedly coupled to the screw, which is in turn fixedly connected to the mounting bracket. The drive motor rotates the screw, driving the nut and the mounting bracket to move synchronously. Of course, in other embodiments, the transverse actuator can also be another linear actuator, as long as it can drive the protective layer 1 to move laterally in a predetermined direction and spacing.

[0056] The winding assembly 22 includes a reel 221, a reel 222, a motor 223, and a linkage 224; the reel 221 and the reel 222 are both installed in the welding device 10; the output end of the motor 223 is fixedly connected to the reel 222 for driving the reel 222 to rotate; the linkage 224 is installed between the reel 221 and the reel 222. In some embodiments, in order to prevent the protective layer 1 from sticking to the welding device 10 and to enable the protective layer 1 to move to the outside of the chip 20 to be welded, a push rod can be further provided in the welding device 10. The push rod is located at both ends of the protective layer 1, and a gap can be left between the protective layer 1 and the welding device 10 so that the chip 20 to be welded can enter the gap. Furthermore, a linkage 224 can be used to drive the ejector rod, so that when the winding assembly 22 winds up the protective layer 1, the ejector rod moves into the welding device 10 until it is completely received into the welding device 10. At the same time, after the chip is bumped and electroplated to form an array of solder balls on the chip, the winding device is reset, and the ejector rod is reset by the linkage 224, and the protective layer 1 can be removed from the chip.

[0057] The auxiliary replacement assembly 5 is used to assist in replacing the protective layer 1 when the protective ability of the protective layer 1 is lower than a preset index. The auxiliary replacement assembly 5 includes a lock 51, a limiter 52 and an adjustment cylinder 53, and may also include an early warning unit. The adjustment cylinder 53 is elastically installed in the welding device 10, and the adjustment cylinder 53 is arranged parallel to the unwinding cylinder 221 and the winding cylinder 222. The adjustment cylinder 53 can be installed in the welding device 10 by a spring or an elastic sheet. When the winding assembly 22 drives the protective layer 1 to move, the adjustment cylinder 53 moves with the protective layer 1 and cooperates with the unwinding cylinder 221 to prevent the protective layer 1 from being overstretched, resulting in a decrease in protective ability or damage.

[0058] The output end of the motor 223 is fixedly connected to the take-up drum 222 and is used to drive the take-up drum 222 to rotate. The linkage 224 is installed between the unwinding drum 221 and the take-up drum 222. When the winding assembly 22 fits the protective layer 1 on the chip 20 to be welded, the linkage 224 causes the take-up drum 222 and the unwinding drum 221 to rotate relative to each other, stretching the protective layer 1 to both sides. The lock 51 is installed on the unwinding drum 221 and is used to lock the unwinding drum 221. The limiter 52 is set on the outside of the take-up drum 222, and the take-up drum 222 is limited by extending one end of the limiter 52 into the positioning hole 12. When replacing the protective layer 1, the limiter 52 is moved out of the positioning hole 12 of the previous protective layer 1, and the motor 223 is started to drive the winding drum 222 to rotate, and the protective layer 1 to be replaced is wound onto the winding drum 222. During this process, the locker 51 is opened so that the protective layer 1 on the unwinding drum 221 can be pulled out. When the next protective layer 1 is just below the chip 20 to be welded, one end of the limiter 52 is just snapped into the positioning hole 12 to realize the positioning of the protective layer 1. The locker 51 is reset to lock the unwinding drum 221, so that the unwinding drum 221 can only rotate in a small range under the action of the winding spring.

[0059] The warning unit is used to sound an alarm when the remaining number of protective layers 1 falls below a preset number. The warning unit includes a microswitch and an alarm. The microswitch can be installed on the unwinding drum 221. When only the last layer of protective layer 1 remains, the protective layer 1 is pulled out as a whole, the microswitch closes, and the alarm emits an audible and visual alarm, reminding the operator to replace the protective layer 1 roll.

[0060] The positioning assembly is used to position the chip 20 to be welded and the protective layer 1 so that the chip 20 to be welded, the protective layer 1 and the chip 20 to be welded are positioned relative to each other.

[0061] The positioning assembly includes an imaging unit, a substrate positioning unit, and a protective layer 1 positioning unit. The imaging unit is used to obtain the image of the chip to be welded, the image of the welding substrate, and the image of the protective layer, and to identify the chip position. The imaging unit can be a CCD camera, which is placed on both sides of the protective layer 1 and on the substrate clamping device of the welding device 10. The imaging unit collects the protective layer image and the chip image according to a preset acquisition frequency, and is used to detect the position of the substrate and the position of the protective layer 1 in real time. Since the position of the substrate generally does not change, in the actual positioning operation, it is only necessary to record the position of the substrate and set the moving path so that the welding device 10 can be accurately moved above the welding substrate each time.

[0062] The substrate positioning unit includes an irregularly shaped positioning block, and a clamping device with a positioning groove that mates with the positioning block. The clamping device is used to clamp the soldering substrate. The positioning block can be one or more. If there is only one positioning block, it is asymmetrical to ensure accurate positioning.

[0063] The protective layer 1 positioning unit includes multiple positioning rods, which are fixedly connected to the welding device 10. The bottom ends of the positioning rods are spherical. The protective layer 1 is provided with multiple positioning holes 12 that match the positioning rods. When the winding assembly 22 rolls the protective layer 1 onto the chip surface, the protective layer 1 is gradually stretched to a horizontal state until each positioning rod is aligned with the positioning hole 12, so that the spherical end of the positioning rod extends into the positioning block, forming a precise positioning of the protective layer 1.

[0064] The inspection module is used to test the flatness and protective capabilities of protective layer 1. After long-term use, protective layer 1 gradually degrades due to high temperatures and the effects of sputtered solder molten metal. Quality inspection and timely replacement of protective layer 1 not only maintains efficient chip protection but also reduces protection costs.

[0065] The detection module includes a flatness recognition unit and a protective capability recognition unit. The flatness recognition unit is used to identify the flatness of the front surface of the protective layer 1. By comprehensively identifying the flatness and protective capability of the protective layer, it is determined whether the protective layer can continue to be used.

[0066] The recognition process of the flatness recognition unit includes:

[0067] A flat frontal image of the protective layer 1 in its stretched state is obtained. During the protective process, the protective layer 1 can exist in two states: flat and curved. During welding preparation, the protective layer 1 is stretched by the reel, but due to the low stretching force, the overall shape remains curved. During welding, the protective layer 1 is stretched to a horizontal state by the drive assembly 2 and the positioning assembly. At this point, the flat frontal image is a complete square. The reserved cutting notches at both ends of the protective layer 1 allow the image of a single protective layer to be completely segmented.

[0068] Grayscale processing is performed on the planar front image, and a plurality of first acquisition points are set in the planar front image after the grayscale processing, and the brightness of each first acquisition point is obtained.

[0069] Construct a flatness regression model. Use the flatness regression model to identify each first acquisition point and output multiple first flatnesses. The construction process of the flatness regression model includes:

[0070] Calculate the brightness gradient and brightness curvature of multiple acquisition points. The formula is expressed as:

[0071]

[0072]

[0073] Where, is the brightness gradient of the i-th acquisition point, is the brightness of the i-th collection point, is the brightness of the i-th collection point, is the brightness curvature of the i-th acquisition point, is the brightness gradient of the i-1th acquisition point.

[0074] The brightness variance is calculated using a sliding window, and the formula is expressed as:

[0075]

[0076] Where w is the window size, Y j is the brightness of the jth acquisition point in the window, and is the average brightness of all acquisition points in the window.

[0077] Select a concentrated brightness area of ​​multiple collection points and determine the ideal brightness based on the concentrated brightness area. The concentrated brightness area can be sorted by brightness and the brightness of the middle 80% of collection points is retained. The average value of these collection points is then calculated as the ideal brightness.

[0078] Select the two first acquisition points with the largest difference from the ideal brightness, the first acquisition point with the largest brightness gradient, and the first acquisition point with the largest brightness curvature, and calculate the first flatness R1. The formula is:

[0079]

[0080] Where K is the conversion coefficient, which represents the mapping relationship between the brightness and thickness of the first acquisition point. 、 are the brightness of the two first acquisition points with the largest difference from the first ideal brightness, is the first ideal brightness, is the brightness of the first acquisition point with the largest brightness gradient, is the brightness of the first acquisition point with the largest brightness curvature, 、 、 are weight coefficients, and + + =1, is the correction factor, is the average variance of multiple first acquisition points.

[0081] Acquire a curved surface front image and a curved surface side image of the protective layer 1 when the protective layer 1 is in a curved state.

[0082] A three-dimensional image of the protective layer is obtained by performing three-dimensional modeling based on the front image and the side image of the curved surface.

[0083] A plurality of second acquisition points are set in the curved surface front image, and the brightness of each second acquisition point is acquired.

[0084] Mark the 3D coordinates of each second acquisition point in the 3D image of the protection layer, and correct the brightness of the second acquisition point according to the normal vector of the tangent plane where the 3D coordinates are located. The corrected brightness is expressed as:

[0085]

[0086] Where, is the corrected brightness, θ is the angle between the normal vector of the tangent plane at the second acquisition point i and the XY plane in the three-dimensional coordinate system, is the brightness of the i-th second acquisition point.

[0087] The second flatness R2 is calculated using the brightness-flatness fitting method, and the formula is expressed as:

[0088]

[0089] Where, 、 are the brightness of the two second acquisition points with the largest difference from the ideal brightness, is the second ideal brightness, is the brightness of the second acquisition point with the largest brightness gradient, is the brightness of the second acquisition point with the largest brightness curvature, is the average variance of multiple second acquisition points.

[0090] Perform weighted operation on the first flatness and the second flatness to obtain the comprehensive flatness, which is expressed as:

[0091]

[0092] Where, For comprehensive flatness, 、 are weight coefficients, and + =1. In this embodiment, respectively set =0.7, =0.3.

[0093] The protection capability identification unit is used to identify the protection capability of the protection layer 1 according to the protection layer image.

[0094] The identification process of the protection capability identification unit includes:

[0095] Preprocess the protective layer image. This includes grayscale processing, image denoising, contrast enhancement, and normalization. Grayscale processing reduces the complexity of image operations, image denoising improves image processing, contrast enhancement improves recognition accuracy, and normalization unifies the size of the captured image.

[0096] Construct an image recognition model based on a neural network. In this embodiment, an improved Resnet neural network is used to construct an image recognition model, which includes a convolutional layer, a residual layer, a pooling layer, and an output layer. Among them, the convolutional layer adopts a 7×7 convolution kernel and uses Relu6 as the activation function. The residual layer includes 4 residual block groups, and the number of residual blocks in the 4 residual block groups is 3, 4, 6, and 3 respectively. The pooling layer includes a 3×3 maximum pooling layer located between the residual layer and the convolutional layer, and a 7×7 global average pooling layer located between the residual layer and the output layer. The output layer adopts a 512-dimensional fully connected layer.

[0097] The image recognition model was trained using a historically collected set of protective layer images. The protective layer image set was divided into a training set and a test set with an 8:2 ratio. The model performance was tested using the loss function, with accuracy and confidence as the model testing evaluation criteria.

[0098] The preprocessed protection layer image is input into the trained image recognition model to output the protection capability of protection layer 1.

[0099] After the detection module identifies the flatness and protection capability of the protective layer 1, it determines whether it exceeds the preset flatness and protection capability indicators. If so, it sends a signal to replace the protective layer 1 to control the auxiliary replacement component 5 to replace the protective layer 1.

[0100] Working principle:

[0101] In the flip-chip soldering protection structure of this embodiment, during the soldering operation, the position of the chip 20 to be soldered is first identified by the positioning component, and the soldering device 10 adsorbs the chip 20 to be soldered at a preset angle so that the chip 20 to be soldered is aligned with the direction of the protective layer 1. Subsequently, the soldering device 10 flips the chip 20 to be soldered over and activates the transverse drive to move the winding assembly 22 toward the position of the chip 20 to be soldered until the protective layer 1 is just above the chip 20 to be soldered. The motor 223 is started to drive the winding drum 222 to rotate, and the winding drum 222 and the unwinding drum 221 are rotated relative to each other through the linkage 224, so that the protective layer 1 is completely attached to the chip 20 to be soldered, and each through-hole 11 on the protective layer 1 is just located at the point to be soldered on the chip. Subsequently, a bump plating device is used to electroplate multiple arrays of solder balls on the chip, and the protective layer 1 is removed after the solder balls are cooled and formed.

[0102] Before use, protective layer 1 is tested for its smoothness and protective capability by a testing module. If the smoothness or protective capability of protective layer 1 exceeds preset indicators, it indicates that the surface of protective layer 1 is uneven or the protective layer may be cracked. This can easily cause gaps during chip soldering, causing non-soldering areas on the chip to splash onto the solder liquid, affecting soldering quality. In this case, auxiliary replacement assembly 5 is used to replace the current protective layer 1 with a new one, ensuring comprehensive chip protection.

[0103] During the chip-to-solder substrate soldering process, the substrate is placed on a soldering table and secured with a clamping device. The soldering device 10 then flips the chip 20 to be soldered, moving it directly above the substrate. The substrate positioning unit then positions the chip 20 so that the array of solder bumps completely aligns with the solder points on the substrate. The heater in the soldering device 10 is then activated, melting the solder balls and connecting them between the substrate and the chip 20, creating a reliable bond.

[0104] In general, the flip-chip welding protection structure provided in this embodiment detects the protective layer 1 so that the protective layer 1 can provide all-round protection for the chip during the welding process. Through the cooperation of the winding component 22 and the auxiliary replacement component 5, not only can the protective layer be quickly adhered to the chip, but also the protective layer 1 can be replaced in time when the protective capacity of the protective layer is insufficient. The replacement and bonding processes can be realized during the movement of the chip without affecting the welding efficiency. At the same time, the protection effect is improved, the welding quality is guaranteed, and the protection cost is reduced.

[0105] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A flip chip welding protection structure, mounted on a welding device (10) and located outside a chip to be welded (20), characterized in that: include: A protective layer (1) is arranged outside the chip to be welded (20); a plurality of through holes (11) are provided on the protective layer (1), and the through holes (11) have the same shape, size and spacing as the welding area on the chip to be welded (10); A driving assembly (2) for driving the protective layer (1) to fit onto the chip to be welded (20); the driving assembly (2) comprises a transverse drive and a winding assembly (22); the transverse drive is mounted on the welding device (10) and is used to drive the protective layer (1) to move transversely so that the protective layer (1) approaches or moves away from the chip to be welded (20); the winding assembly (22) is mounted in the welding device (10); the winding assembly (22) is used to wind up the protective layer (1) so that the protective layer (1) fits onto the chip to be welded (20); the The winding assembly (22) includes a reel (221), a reel (222), a motor (223), and a linkage (224); the reel (221) and the reel (222) are both installed in the welding device (10); the output end of the motor (223) is fixedly connected to the reel (222) for driving the reel (222) to rotate; the linkage (224) is installed between the reel (221) and the reel (222); multiple pieces of the protective layer (1) are connected in pairs and reeled on the reel (221) and the reel (222); A positioning component, used for positioning the chip to be welded (20) and the protective layer (1), so that the chip to be welded (20) and the protective layer (1) are positioned relative to each other; A detection module, used for detecting the flatness and protective capability of the protective layer (1); An auxiliary replacement component (5) is used to assist in replacing the protective layer (1) when the protective capability of the protective layer (1) is lower than a preset index.

2. The flip chip soldering protection structure according to claim 1, characterized in that: The positioning assembly comprises an imaging unit, a substrate positioning unit and a protective layer (1) positioning unit; the imaging unit is used to obtain an image of a chip to be welded, an image of a welding substrate and an image of a protective layer, and to identify the position of the chip; the substrate positioning unit comprises a positioning block, the positioning block is irregularly shaped, a clamping device is provided with a positioning groove matching the positioning block, and the clamping device is used to clamp the welding substrate; the protective layer (1) positioning unit comprises a plurality of positioning rods, the positioning rods are fixedly connected to the welding device (10), and the bottom ends of the positioning rods are set to be spherical, and the protective layer (1) is provided with a plurality of positioning holes (12) matching the positioning rods.

3. The flip chip soldering protection structure according to claim 2, characterized in that: The detection module comprises a flatness recognition unit and a protection capability recognition unit; the flatness recognition unit is used to recognize the flatness of the front surface of the protection layer (1); and the protection capability recognition unit is used to recognize the protection capability of the protection layer (1) based on the protection layer image.

4. The flip chip soldering protection structure according to claim 3, characterized in that: The recognition process of the flatness recognition unit includes: Acquiring a planar frontal image of the protective layer (1) when it is in a stretched state; Performing grayscale processing on the planar front image, setting a plurality of first acquisition points in the planar front image after the grayscale processing, and acquiring the brightness of each first acquisition point; The first smoothness is calculated using the brightness-smoothness fitting method; Obtaining a curved surface front image and a curved surface side image of the protective layer (1) when the protective layer (1) is in a curved state; Performing three-dimensional modeling based on the curved surface front image and the curved surface side image to obtain a three-dimensional image of the protective layer; Setting a plurality of second acquisition points in the curved surface front image, and acquiring the brightness of each second acquisition point; Marking the three-dimensional coordinates of each second acquisition point in the three-dimensional image of the protection layer, and correcting the brightness of the second acquisition point according to the normal vector of the tangent plane where the three-dimensional coordinates are located; The second smoothness is calculated using the brightness-smoothness fitting method; Perform weighted operation on the first flatness and the second flatness to obtain the comprehensive flatness.

5. The flip chip soldering protection structure according to claim 4, characterized in that: The brightness-flatness fitting method includes: Calculate the ideal brightness based on the brightness of multiple acquisition points; Calculate the brightness gradient and brightness curvature of each acquisition point; The acquisition point with the largest brightness gradient and the acquisition point with the largest brightness curvature are selected, and the flatness is calculated by combining the two acquisition points with the largest difference from the ideal brightness.

6. The flip chip soldering protection structure according to claim 3, characterized in that: The identification process of the protection capability identification unit includes: Preprocessing the protection layer image; Build an image recognition model based on neural network; Using a historically collected set of protection layer images to train the image recognition model; The pre-processed protective layer image is input into the trained image recognition model to output the protective capability of the protective layer (1).

7. The flip chip soldering protection structure according to claim 2, characterized in that: The auxiliary replacement component (5) includes a locker (51), a limiter (52) and an adjustment cylinder (53); the adjustment cylinder (53) is elastically installed in the welding device (10), and the adjustment cylinder (53) is arranged in parallel with the unwinding cylinder (221) and the winding cylinder (222); when the winding component (22) drives the protective layer (1) to move, the adjustment cylinder (53) moves with the protective layer (1) and cooperates with the unwinding cylinder (221) to prevent the protective layer (1) from being overstretched, resulting in a decrease in protective ability or damage; the locker (51) is installed on the unwinding cylinder (221) and is used to lock the unwinding cylinder (221); the limiter (52) is arranged on the outside of the winding cylinder (222), and the winding cylinder (222) is limited by extending one end of the limiter (52) into the positioning hole (12).

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