Pad repairing method and equipment

Abstract

The invention relates to the technical field of bonding pad repair, and discloses a bonding pad repair method and device, and the method comprises the steps: obtaining the information of a bonding pad dead pixel on a substrate, and determining the position of a to-be-repaired bonding pad based on the information of the bonding pad dead pixel; pressing a mask on the substrate according to the position of the bonding pad to be repaired, so that the position of the bonding pad to be repaired is exposed from the mask gap; a metal film is arranged at the position, exposed out of the mask gap, of the bonding pad to be repaired; and melting and sputtering metal on the metal film into nano liquid drops by using a laser sputtering method, and enabling the nano liquid drops to drop in the mask gap to cover the position of the bonding pad to be repaired so as to form a metal accumulation layer. The laser sputtering technology is adopted for repairing the damaged metal bonding pad, metal on the metal film is melted to form superfine metal liquid drops through the instantaneous effect of high-power pulse laser, the metal liquid drops are sputtered to the substrate to be solidified to form the welding effect, the repairing adhesive force is higher, and the repairing stability is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of pad repair, and in particular to a pad repair method and equipment. Background Art

[0002] As the display LED packaging field develops towards lightweight, high-resolution, and transparent packaging, a new packaging method based on glass substrates (COG: Chip on Glass) has appeared on the market. Due to its reliability and stability in glass-based displays, it is widely used in the MiniLED and MicroLED fields. However, during the mounting and rework process on the COG substrate, the LED pads and IC pads on the substrate are easily damaged due to various reasons.

[0003] The traditional coating pad repair method has a low success rate. The traditional coating pad repair method is to apply a conductive material on the pad. The conductive material is solidified by baking the organic solvent in the material to volatilize the organic solvent. The solvent bonds the metal to the pad, but it cannot directly melt the metal, resulting in insufficient bonding between the metal particles. When the pad falls off as a whole, the conductive material is directly coated on the glass substrate. The surface of the glass substrate is relatively smooth and lacks sufficient roughness, resulting in insufficient mechanical bonding between the conductive material and the substrate, which easily causes it to fall off again. Summary of the invention

[0004] In view of this, the present invention provides a pad repair method and device to solve the problem of insufficiently strong bonding between metal particles and between conductive materials and substrates in conventional coating-type pad repair methods.

[0005] In a first aspect, the present invention provides a pad repair method, comprising:

[0006] Acquire the bad spot information of the pad on the substrate, and determine the position of the pad to be repaired based on the bad spot information of the pad;

[0007] According to the position of the pad to be repaired, a mask is pressed onto the substrate so that the position of the pad to be repaired is exposed from the gap of the mask;

[0008] Arranging a metal film at a position where the pad to be repaired is exposed from the mask gap;

[0009] Laser sputtering is used to melt the metal on the metal film and sputter it into nano droplets, so that the nano droplets fall into the gap of the mask and cover the position of the pad to be repaired to form a metal accumulation layer.

[0010] The beneficial effects of the above pad repair method are:

[0011] The present invention uses a laser sputtering process to repair damaged metal pads. Through the instantaneous action of a high-power pulsed laser, the metal on the metal film is melted to form extremely fine metal liquid droplets, which are sputtered onto the substrate and solidified to form a welding effect. Compared with the prior art solution of solidifying with organic solvents, the present invention directly melts the metal and adheres it to the substrate, so the repair adhesion is higher and the repair stability is enhanced.

[0012] When performing metal sputtering, the present invention covers the non-repaired area with a mask, leaving only the area to be repaired exposed, so that fine metal droplets can accurately fall on the pad area to be repaired, thereby improving the accuracy and consistency of the repair; the mask isolates the influence on other areas of the substrate, and the mask can effectively protect the parts of the substrate that do not need to be processed, preventing these areas from being affected by laser or metal sputtering.

[0013] In addition, the present invention only requires laser sputtering to complete the repair. Laser sputtering can directly deposit metal materials onto the pads that need to be repaired without the need for intermediate transfer or bonding steps, greatly reducing the process steps.

[0014] In an optional implementation, the acquiring the bad pad information on the substrate and determining the position of the pad to be repaired based on the bad pad information includes:

[0015] Setting a marking point on the substrate, and setting a two-dimensional code recording the bad point information of the pad corresponding to the substrate on the substrate;

[0016] Load the substrate, scan the QR code on the substrate, obtain the bad pixel information contained in the QR code through the Internet and store it in the controller;

[0017] The substrate is moved to the bottom of the visual recognition camera by the motion platform, and the substrate is preliminarily positioned by scanning the marking points on the substrate; according to the bad pixel information read, the motion platform is controlled to drive the substrate to move, and the position of the pad to be repaired is accurately located.

[0018] The above-mentioned pad repair method includes loading the substrate, scanning the QR code, preliminary positioning and precise positioning. The steps are clear and the degree of automation is high, which reduces manual intervention, improves production efficiency and reduces the difficulty of operation. Through the above series of steps, the bad pads on the substrate can be efficiently and accurately located and repaired, thereby improving the overall production efficiency and product quality. Through precise positioning and automated repair process, it is ensured that each pad can be repaired with high quality.

[0019] In an optional implementation, the step of pressing a mask onto the substrate according to the position of the pad to be repaired so that the position of the pad to be repaired is exposed from a gap in the mask comprises:

[0020] Based on the acquired position of the pad to be repaired, the substrate is driven to move horizontally by the motion platform to align the mask gap with the pad to be repaired;

[0021] The substrate is driven up by the motion platform so that the mask is pressed against the substrate.

[0022] The above pad repair method ensures that the mask gap is accurately aligned with the pad to be repaired, thereby preventing other areas from being repaired by mistake or being subjected to unnecessary treatment. The use of the mask can limit the deposition of the repair material only on the pad to be repaired, avoiding unnecessary treatment of other parts of the substrate. The substrate is driven up by the motion platform, so that the mask is pressed against the substrate, ensuring that the mask is in close contact with the substrate, preventing displacement or gap in the subsequent repair process, and ensuring the accuracy and stability of the repair operation.

[0023] In an optional embodiment, before the substrate is lifted by the motion platform, the height of the pad to be repaired is measured by a laser height measuring mechanism to obtain the required lifting position of the motion platform, and the lifting of the motion platform is controlled based on the required lifting position of the motion platform, thereby achieving precise extrusion contact between the mask and the substrate.

[0024] In an optional implementation, before aligning the mask gap with the pad to be repaired, the position of the mask gap is calibrated in advance by a bottom calibration camera.

[0025] In an optional embodiment, the method of melting the metal on the metal film and sputtering it into nano droplets by laser sputtering includes:

[0026] Set the sputtering path;

[0027] The movement of the laser beam is controlled based on the sputtering path so that the laser beam scans the metal film at least once; wherein the laser beam scans the metal film once means that the laser beam moves from the starting end of the sputtering path to the ending end of the sputtering path according to the set path.

[0028] The above-mentioned pad repair method, by setting a specific sputtering path, can make the laser beam evenly cover the area to be repaired according to a predetermined trajectory, which helps to ensure that the fine metal droplets are evenly distributed on the pad, thereby forming a smoother and more consistent repair layer. By controlling the movement path of the laser beam, the position and amount of metal deposition can be very accurately controlled, and high-precision repair can be achieved, especially in small pads or complex structures that require delicate operations. The laser beam scans quickly along the preset path and can stay at each point for a short time, thereby reducing heat accumulation in local areas.

[0029] In an optional embodiment, the sputtering path is set based on the scanning time:

[0030] The form of the sputtering path changes based on the increase in scanning time, and thus when scanning the metal film, different forms of sputtering paths can be used in turn, so that each layer of metal droplets can be deposited according to different sputtering paths, and the distribution of the metal droplets can be more finely controlled, so that the formed metal accumulation layer is more uniform, and the problem of local excessive thickness or thinness is reduced; and the metal bonding strength is higher, and different forms of sputtering paths can optimize the distribution of laser energy on the substrate and promote better metallurgical bonding ability.

[0031] In an optional embodiment, the form of the sputtering path remains unchanged based on the increase in scanning time, that is, multiple layers of metal droplets are sputtered along the same sputtering path. By repeating the same sputtering path multiple times, the thickness of the metal layer can be gradually increased in the area to be repaired. Each round of sputtering can be accurately superimposed on the previous layer, and the thickness of the final deposited layer can be accurately controlled to ensure that the desired repair thickness is achieved.

[0032] In an optional embodiment, the sputtering path is a reciprocating sputtering path so that the laser beam is evenly irradiated onto the metal film; the reciprocating sputtering path is in the form of a vertical reciprocating sputtering path, a horizontal reciprocating sputtering path, or an inclined reciprocating sputtering path.

[0033] In an optional embodiment, the laser beam scans the metal film at least once by driving a picosecond laser generator with a laser galvanometer; and the sputtering path is achieved by customizing the laser galvanometer motion path.

[0034] In an optional embodiment, after the laser beam scans the metal film once, the position of the metal film is changed so that the position of the metal film not irradiated by the laser beam is moved to the position of the mask gap for the next scan. Each time the metal film is sputtered, the position of the metal film is changed, thereby ensuring that each sputtering generates droplets arranged according to the sputtering path, thereby achieving the expected sputtering effect.

[0035] In an optional embodiment, before controlling the movement of the laser beam based on the sputtering path and scanning the metal film at least once, the parameters of the laser beam are adjusted to control the temperature distribution and solidification rate during the repair process, which is beneficial to optimize the organizational morphology of the deposited layer and further improve the bonding quality between the deposited layer and the substrate.

[0036] In an optional embodiment, the method is applied to ultra-thin pad repair.

[0037] In an optional embodiment, the method can also be used to repair damaged circuits in non-pad areas of the substrate.

[0038] In a second aspect, the present invention further provides a pad repair device, which is based on the pad repair method and comprises:

[0039] a rack having a mounting platform;

[0040] The gantry is arranged above the frame and forms a working space for carrying out repair work between the gantry and the mounting platform of the frame;

[0041] A motion platform, arranged on the mounting platform, for driving the substrate to move in horizontal and vertical directions;

[0042] A picosecond laser generator is arranged on the gantry and is used to emit a laser beam;

[0043] A laser galvanometer, which is arranged on the gantry and is used to control the deflection of the laser beam emitted by the picosecond laser generator;

[0044] The metal film roll release mechanism is arranged on the gantry, located between the laser galvanometer and the motion platform, and is used to release the metal film onto the mask;

[0045] The clamping mechanism is arranged on the gantry and is used for clamping and positioning the mask and the metal film.

[0046] The beneficial effects of the above pad repair equipment are:

[0047] The mask and the metal film can be fixed by a clamping mechanism, and the substrate can be moved to a set position by a motion platform so that the position of the pad to be repaired on the substrate is exposed from the mask gap. Then, under the action of the laser beam emitted by the picosecond laser generator, the metal on the metal film melts and sputters into nanodroplets, which fall into the mask gap and cover the position of the pad to be repaired to form a metal accumulation layer, thereby realizing automatic repair of the pad.

[0048] In an optional embodiment, a metal film winding mechanism is also provided on the gantry. After the picosecond laser generator completes each scan of the metal film, the metal film winding mechanism controls the metal film to be wound up so as to cover the mask gap with a new metal film.

[0049] In an optional embodiment, the pad repair device further includes:

[0050] A visual recognition camera, set on the gantry, is used to accurately locate the position of the pad to be repaired;

[0051] and / or, a laser height sensor, arranged on the gantry, for detecting the height of the substrate to be repaired, and cooperating with the motion platform to rise to a corresponding height so as to cover the mask onto the substrate;

[0052] and / or, a bottom calibration camera, which is arranged on the motion platform and is used to calibrate the position of the mask gap so that the mask gap can be aligned with the pad to be repaired during processing;

[0053] and / or, a buffer device, disposed on the clamping mechanism, for buffering the substrate when the mask contacts the substrate, so as to prevent the mask from damaging the substrate;

[0054] And / or, a conveying and adsorption device is used to convey the substrate between the feeding and discharging platform and the moving platform, and to adsorb and level the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A schematic structural diagram of a pad repair device provided by the present invention;

[0056] Figure 2 A flow chart of a pad repair method provided by the present invention;

[0057] Figure 3 This is a schematic diagram of the structure of a damaged pad to be repaired according to the present invention;

[0058] Figure 4 It is a schematic diagram of the structure when the mask of the present invention is pressed onto a substrate;

[0059] Figure 5 It is a schematic diagram of the structure of the metal material of the present invention when it is sputtered;

[0060] Figure 6 It is a schematic diagram of the structure after the pad is repaired according to the present invention;

[0061] Figure 7 It is a structural schematic diagram of the present invention when the sputtering path is set to a vertical serpentine shape;

[0062] Figure 8 It is a structural schematic diagram of the present invention when the sputtering path is set to a horizontal serpentine shape;

[0063] Fig. 9 It is a structural schematic diagram of the present invention when the sputtering path is set to an inclined serpentine shape;

[0064] Fig.10 This is a diagram showing the effect of the laser sputtering test of the present invention.

[0065] Description of reference numerals:

[0066] 1. Frame, 2. Gantry, 3. Feeding and discharging platform, 4. Motion platform, 5. Conveying and adsorption device, 6. Picosecond laser generator, 7. Laser galvanometer, 8. Metal film roll release mechanism, 9. Clamping mechanism, 10. Mask, 101. Mask gap, 11. Buffer device, 12. Visual recognition camera, 13. Laser height sensor, 14. Bottom calibration camera, 15. Metal film winding mechanism, 16. Sputtering material, 17. Repaired pad, a. First insulating layer, b. First metal layer, c. Falling and damaged pad area, d. Second insulating layer, e. Second metal layer, f. Metal foil scanned by picosecond laser, g. Nanometal formed by sputtering. DETAILED DESCRIPTION

[0067] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0068] As the display LED packaging field develops towards thinness, high resolution, and transparent packaging, a new packaging method based on glass substrates (COG: Chip on Glass) has emerged on the market. Due to its reliability and stability in glass-based displays, it is widely used in the MiniLED and MicroLED fields. However, during the mounting and repair process on the COG substrate, the LED pads and IC pads on the substrate are easily damaged due to various reasons. Figure 3 , a (side) diagram of a damaged COG pad film layer structure is provided. The COG pad film layer structure includes a first insulating layer a, a first metal layer b, a second insulating layer d, a second metal layer e and a pad. When the pad falls off, a recessed damaged pad area c will be formed on its structure.

[0069] The traditional coating pad repair method has a low success rate. The traditional coating pad repair method is to apply a conductive material on the pad. The conductive material is solidified by baking the organic solvent in the material to volatilize the organic solvent. The solvent bonds the metal to the pad, but it cannot directly melt the metal, resulting in insufficient bonding between the metal particles. When the pad falls off as a whole, the conductive material is directly coated on the glass substrate. The surface of the glass substrate is relatively smooth and lacks sufficient roughness, resulting in insufficient mechanical bonding between the conductive material and the substrate, which easily causes it to fall off again.

[0070] Based on this, the present invention provides a pad repair method, which uses a laser sputtering process to repair a damaged metal pad, and directly melts the metal and adheres it to a substrate, so that the repair adhesion is higher and the repair stability is enhanced.

[0071] The traditional coating pad repair method has a low repair efficiency, mainly because the coated conductive material needs to be thermally cured. Even with laser heating, it takes about 5 minutes to complete the repair of a pad.

[0072] The present invention uses a laser sputtering process to repair damaged metal pads. The laser beam can concentrate a large amount of energy in a very small area, which can quickly heat the material to the required temperature, thereby accelerating the repair process. After laser heating, the material can cool down at a very fast speed, which helps to form a denser microstructure and shorten the entire repair cycle.

[0073] The pads repaired by the traditional coating pad repair method cannot form ultra-thin flat pads and need to be corrected with a milling cutter. This process method causes the milling cutter to wear out quickly, and the milling cutter is a consumable. The price of a milling cutter with a small diameter is expensive, which increases the repair cost.

[0074] The present invention uses a laser sputtering process to repair damaged metal pads. Through a multi-axis motion platform driven by a servo motor and / or a high-speed scanning laser galvanometer, etc., it ensures that position control accurate to the micron level can be achieved even in a very small space, which is very suitable for manufacturing ultra-thin pads.

[0075] The traditional coating pad repair method requires too high Z-axis accuracy of the equipment, usually requiring an accuracy of ±0.5μm, because the coating head needs to be in contact with the surface of the glass substrate during the coating process, and the thickness of the pad to be repaired on the substrate is too thin.

[0076] The present invention uses a laser sputtering process to repair damaged metal pads. Unlike traditional coating methods, laser sputtering does not require any physical tools to directly contact the substrate surface, avoiding positioning errors and uneven pressure caused by mechanical contact. This feature is particularly suitable for processing very thin and fragile materials, such as ultra-thin pads on glass substrates.

[0077] The specific embodiments of the present invention are described in detail below in conjunction with the pad repair device of the first aspect of the present invention and the pad repair method of the second aspect of the present invention.

[0078] According to an embodiment of the present invention, in a first aspect, a pad repair device is provided, Figure 1 As shown, it includes a frame 1, a gantry 2, a motion platform 4, a picosecond laser generator 6, a laser galvanometer 7, a metal film roll releasing mechanism 8 and a clamping mechanism 9.

[0079] The frame 1 has a mounting platform for carrying various structures and systems of the repair equipment.

[0080] The gantry 2 is installed above the frame 1, and forms a working space for performing repair work with the mounting platform of the frame 1. The picosecond laser generator 6, the laser galvanometer 7, the metal film roll release mechanism 8, the clamping mechanism 9, the mask 10, the buffer device 11, the visual recognition camera 12, and the laser height sensor 13 are all installed on the gantry 2.

[0081] The motion platform 4 is arranged on the mounting platform and can, under the action of the driving structure, implement movement in the X and Y directions and implement the rise and fall of the platform in the Z direction. The motion platform 4 is a voice coil platform, which is a high-performance precision motion control device. The voice coil motor generates electromagnetic force by applying current between the fixed magnet and the moving voice coil, thereby driving the moving part to move in a straight line.

[0082] The conveying and adsorption device 5 and the bottom calibration camera 14 are installed on the motion platform 4. The movement in the X and Y directions drives these modules to move under the corresponding mechanism to achieve high-precision pad repair operations. The movement in the Z direction of the platform drives the substrate to move to achieve the clamping and loosening of the substrate and the mask.

[0083] The picosecond laser generator 6 is arranged on the gantry 2 and is used to emit a laser beam. The picosecond laser generator 6 is a laser with a pulse width of picoseconds, and has the characteristics of ultra-short pulse width at the picosecond level, adjustable repetition frequency, and high pulse energy. It has been increasingly widely used in the fields of biomedicine, optical parametric oscillation, and biological microscopic imaging, and has gradually become an increasingly important tool in modern biological imaging and analysis systems. In the processing of this embodiment, the picosecond laser generator 6 is used as a sputtering laser energy source, and each laser beam is emitted from it.

[0084] The laser galvanometer 7 is arranged on the gantry 2 and is used to control the deflection of the laser beam emitted by the picosecond laser generator 6. The laser scanner is also called the laser galvanometer 7, which is composed of an XY optical scanning head, an electronic drive amplifier and an optical reflective lens. The signal provided by the computer controller drives the optical scanning head through the drive amplifier circuit, thereby controlling the deflection of the laser beam in the XY plane. Scanning principle: The scanning pattern is a two-dimensional effect pattern, so the scanning motor is controlled by two motors in the X direction and the Y direction. The position of a point is determined at one moment, and the position of different points at different moments is controlled by the scanning frequency to achieve the transformation of the entire scanning pattern. The lower the scanning frequency (speed), the more obvious the pattern flickers.

[0085] The metal film roll release mechanism 8 is arranged on the gantry 2, between the laser galvanometer 7 and the motion platform 4, and is used to release the metal film onto the mask 10. The metal film roll release mechanism 8 includes a release wheel and a first drive motor for controlling the rotation of the release wheel. The release wheel is wound with a metal film roll, which is made of an ultra-thin metal film tape, and the material can be selected from gold foil, silver foil, copper foil, etc.

[0086] The metal film winding mechanism 15 is arranged on the gantry 2. After the picosecond laser generator 6 completes scanning of the metal film each time, the metal film winding mechanism 15 controls the metal film to be wound up so as to cover the new metal film to the mask gap 101. The metal film winding mechanism 15 includes a winding wheel and a second drive motor for controlling the rotation of the winding wheel. The sputtering position of the tape is fixed above the clamping mechanism 9 by an auxiliary wheel, and the two sides are a release wheel and a winding wheel, which are responsible for releasing the tape and collecting the waste tape respectively. The release wheel is equipped with a photoelectric sensor to detect the consumption of the film.

[0087] The clamping mechanism 9 is arranged at the front lower part of the gantry 2, and is used to clamp and position the mask 10 and the metal film. Buffer devices 11 are designed on both sides of the clamping mechanism, which are used to buffer the substrate when the mask 10 contacts the substrate to prevent the mask 10 from damaging the substrate. The buffer device 11 can be a spring buffer device or other types of buffer devices.

[0088] The above-mentioned pad repair equipment can fix the mask 10 and the metal film through the clamping mechanism 9, and drive the substrate to move to the set position through the motion platform 4, so that the position of the pad to be repaired on the substrate is exposed from the mask gap 101, and then under the action of the laser beam emitted by the picosecond laser generator 6, the metal on the metal film melts and sputters into nanodroplets, so that the nanodroplets fall into the mask gap and cover the position of the pad to be repaired to form a metal accumulation layer, thereby realizing automatic repair of the pad.

[0089] The mask 10 is the main control component of the processing technology size and is installed under the clamping mechanism. A notch is opened in the center of the mask according to the size of the pad to be repaired. Different masks need to be replaced to process pads of different specifications. The mask thickness can be selected in different specifications, usually in the range of 20μm to 50μm.

[0090] The pad repair equipment also includes a material loading and unloading platform 3, a visual recognition camera 12, a laser height sensor 13, a bottom calibration camera 14, and a conveying and adsorption device 5.

[0091] The loading and unloading platforms 3 are installed on the left and right sides of the frame 1 and are used to load and unload substrates during the production process.

[0092] The visual recognition camera 12 is arranged on the gantry 2 and is used to accurately locate the position of the damaged pad of the substrate. The visual recognition camera 12 includes a 3D scanning camera, a primary positioning module and a secondary positioning module. The primary positioning module obtains the initial position of the bad point by scanning, and the secondary positioning module uses an AI learning recognition algorithm to perform a secondary accurate positioning of the bad point pad according to the initial position obtained by the primary positioning module.

[0093] The laser height sensor 13 is arranged on the gantry 2 to detect the height of the substrate to be repaired, and cooperates with the motion platform 4 to rise to the corresponding height to cover the mask 10 on the substrate for sputtering repair. At the same time, the laser height sensor 13 has a post-repair detection function to detect whether the height and morphology of the repaired pad are similar to the original pad.

[0094] The bottom calibration camera 14 is arranged on the XY platform of the motion platform 4 and is used to calibrate the position of the mask gap 101 so that the mask gap 101 can be aligned with the pad to be repaired during processing;

[0095] The conveying and adsorption device 5 comprises a conveying device and an adsorption device. The adsorption device is arranged on the conveying device. The conveying device is used to convey the substrate between the feeding and discharging platform 3 and the moving platform 4. The adsorption device can adsorb and level the substrate.

[0096] According to an embodiment of the present invention, a second aspect provides a pad repair method, combining Figures 1 to 10 As shown, including:

[0097] S1. Obtain the bad pad information on the substrate, and determine the position of the pad to be repaired based on the bad pad information.

[0098] S2. Combination Figure 4 As shown, according to the position of the pad to be repaired, the mask 10 is pressed onto the substrate so that the position of the pad to be repaired is exposed from the mask notch 101 .

[0099] S3. Arrange a metal film at the position where the pad to be repaired is exposed from the mask gap 101.

[0100] S4. Combination Fig.10 The laser sputtering test effect diagram shown in the figure uses the laser sputtering method to melt the metal on the metal film and sputter it into nano droplets, so that the nano droplets fall into the gap of the mask and cover the position of the pad to be repaired to form a metal accumulation layer. Figure 5 As shown, the sputtered material 16 is accumulated at the mask gap position. Figure 6 As shown, the conductive pad is printed and cured (front) and the mask is removed to expose the repaired pad 17 .

[0101] The above-mentioned pad repair method uses a laser sputtering process to repair the damaged metal pad. Through the instantaneous action of a high-power pulsed laser, the metal on the metal film is melted to form extremely fine metal liquid droplets, which are sputtered onto the substrate and solidified to form a welding effect. Compared with the prior art solution of solidifying through organic solvents, the present invention directly melts the metal and adheres it to the substrate, which has a higher repair adhesion and enhanced repair stability.

[0102] Repairing damaged metal pads with laser sputtering can achieve higher adhesion, which is mainly attributed to the following factors: 1) The laser beam not only melts or evaporates the contaminants (such as oxides, grease, etc.) on the substrate surface during the repair process, but also changes the microstructure of the material surface through rapid heating and cooling processes. This treatment makes the substrate surface cleaner and increases the surface energy, thereby improving the bonding strength between the newly deposited material and the substrate. 2) Small heat-affected zone: Laser processing has the characteristics of highly concentrated energy, which can achieve rapid heating and cooling in a very small range. This reduces the size of the heat-affected zone, avoids the degradation of material properties caused by long-term high temperature, and is also conducive to the formation of a denser and more uniform interface structure, thereby enhancing adhesion. 3) Metallurgical bonding: Under appropriate process conditions, laser sputtering can not only deposit a new metal layer on the substrate, but also promote a certain degree of metallurgical reaction between the two, that is, atomic-level mixing between the new and old materials. This metallurgical bonding method is much stronger than simple physical adsorption.

[0103] When performing metal sputtering, the present invention covers the non-repaired area with the mask 10, leaving only the area to be repaired exposed, so that the fine metal droplets can accurately fall on the pad area to be repaired, thereby improving the accuracy and consistency of the repair; the mask 10 isolates the influence on other areas of the substrate, and the mask 10 can effectively protect the parts of the substrate that do not need to be processed, preventing these areas from being affected by the laser or metal sputtering. Compared with other complex laser-induced transfer repair methods, the method of the present invention using a mask has higher repair accuracy, is simpler and more direct, and is easy to realize automated operation.

[0104] In addition, the present invention only requires laser sputtering to complete the repair. Laser sputtering can directly deposit metal materials onto the pads that need to be repaired without the need for intermediate transfer or bonding steps, greatly reducing the process steps.

[0105] In one embodiment, obtaining bad pad information on a substrate and determining a position of a pad to be repaired based on the bad pad information includes the following steps:

[0106] S11. Marking points are set at the four corners of the substrate to identify and locate the position of the substrate at one time; and a two-dimensional code recording the bad point information of the pad corresponding to the substrate is set on the back of the substrate, and the two-dimensional code information includes the row and column coordinate information of the bad point of the pad to be repaired.

[0107] S12. Load the substrate, scan the QR code on the substrate with a QR code scanner, obtain the bad pixel information contained in the QR code through the Internet and store it in the controller, which ensures the accuracy and timeliness of the data and avoids repair errors caused by inconsistent data.

[0108] S13. Accurately locate the damaged pad, obtain the X position and Y position of the damaged pad through the visual camera, and obtain the Z height of the damaged pad through the laser height sensor 13. The specific steps are as follows:

[0109] S131. The substrate is moved to the bottom of the visual recognition camera 12 by the high-precision motion platform 4, and the substrate is preliminarily positioned by scanning the marking points on the substrate.

[0110] S132. According to the bad pixel information read, the motion platform 4 is controlled to drive the substrate to move, and the position of the pad to be repaired is accurately located.

[0111] In this embodiment, the whole process includes loading the substrate, scanning the QR code, preliminary positioning and precise positioning. The steps are clear and the degree of automation is high, which reduces manual intervention, improves production efficiency and reduces the difficulty of operation. Through the above series of steps, the bad points of the pads on the substrate can be efficiently and accurately located and repaired, thereby improving the overall production efficiency and product quality. Through precise positioning and automated repair process, it is ensured that each pad can be repaired with high quality.

[0112] In one embodiment, according to the position of the pad to be repaired, the mask 10 is pressed onto the substrate so that the position of the pad to be repaired is exposed from the mask notch 101, including the following steps:

[0113] S21. The height of the pad to be repaired is measured by a laser height measuring mechanism to obtain the required rising position of the motion platform 4 so that the mask can accurately press the substrate.

[0114] S22. Based on the acquired position of the pad to be repaired, the substrate is driven to move horizontally in the X direction and the Y direction by the motion platform 4, and the mask gap 101 is aligned with the pad to be repaired, wherein the position of the mask gap has been calibrated in advance by the bottom vision camera.

[0115] S23. The substrate is lifted up by the motion platform 4 so that the mask 10 presses the substrate tightly. The lifting distance is determined according to the height obtained in S21. A buffer device 11 is installed above the synchronous clamping mechanism 9 to prevent the mask from crushing the substrate.

[0116] In this embodiment, the mask gap is ensured to be precisely aligned with the pad to be repaired, thereby preventing other areas from being repaired by mistake or being subjected to unnecessary treatment. The use of the mask can limit the deposition of the repair material only on the pad to be repaired, avoiding unnecessary treatment of other parts of the substrate. The substrate is driven up by the motion platform, so that the mask is pressed against the substrate, ensuring that the mask is in close contact with the substrate, preventing displacement or gap in the subsequent repair process, and ensuring the accuracy and stability of the repair operation.

[0117] In one embodiment, a high-power pulsed picosecond laser scans the metal film back and forth through a high-speed vibrating laser galvanometer 7, melting the metal on the film and sputtering it into extremely fine nano droplets. The nano droplets fall into the mask gap and cover the damaged pad to form a metal accumulation layer with a thickness of 0.5μm to 2μm. The specific sputtering method path is as follows:

[0118] S41. Set the sputtering path.

[0119] S42. Control the movement of the laser beam based on the sputtering path so that the laser beam scans the metal film at least once. The laser beam scanning the metal film once means that the laser beam moves from the starting end of the sputtering path to the ending end of the sputtering path according to the set path.

[0120] In this embodiment, by setting a specific sputtering path, the laser beam can evenly cover the area to be repaired according to a predetermined trajectory, which helps to ensure that the fine metal droplets are evenly distributed on the pad, thereby forming a smoother and more consistent repair layer. By controlling the movement path of the laser beam, the position and amount of metal deposition can be very accurately controlled, and high-precision repair can be achieved, especially in small pads or complex structures that require delicate operations. The laser beam scans quickly along the preset path and can stay at each point for a short time, thereby reducing heat accumulation in local areas.

[0121] In one embodiment, the sputtering path is set based on the scanning time. The form of the sputtering path changes based on the increase of the scanning time, and then when scanning the metal film, different forms of sputtering paths can be used in sequence, so that each layer of metal droplets can be deposited according to different sputtering paths, and the distribution of metal droplets can be more finely controlled, so that the formed metal accumulation layer is more uniform, and the problem of local excessive thickness or thinness is reduced; and the metal bonding strength is higher, and different forms of sputtering paths can optimize the distribution of laser energy on the substrate and promote better metallurgical bonding ability. For example, the form of the sputtering path can be that the first layer is carried out according to a vertical reciprocating sputtering path, and the second layer is carried out according to a horizontal reciprocating sputtering path.

[0122] As an alternative embodiment, the form of the sputtering path remains unchanged based on the increase in scanning time, that is, multiple layers of metal droplets are sputtered along the same sputtering path. By repeating the same sputtering path multiple times, the thickness of the metal layer can be gradually increased in the area to be repaired. Each round of sputtering can be accurately superimposed on the previous layer, and the thickness of the final deposited layer can be accurately controlled to ensure that the desired repair thickness is achieved.

[0123] In one embodiment, the sputtering path is a reciprocating sputtering path, which is generally set to be a serpentine scanning so that the laser beam is evenly irradiated onto the metal film. The reciprocating sputtering path is in the form of a vertical reciprocating sputtering path, a horizontal reciprocating sputtering path, or an inclined reciprocating sputtering path. The vertical reciprocating sputtering path can be Figure 7 The vertical serpentine scanning path shown; the horizontal reciprocating sputtering path can be Figure 8 The lateral serpentine scanning path shown; the inclined reciprocating sputtering path can be Fig. 9 The inclined serpentine scan path shown.

[0124] In one embodiment, the laser beam scans the metal film at least once, which is performed by driving the picosecond laser generator 6 with the laser galvanometer 7. The sputtering path is achieved by customizing the motion path of the laser galvanometer 7.

[0125] After the metal film is scanned once, part of the metal on the metal film will be sputtered to the area to be repaired, and some gaps will be formed on the metal film. If the metal film is used for the next metal sputtering, the sputtering effect will be affected. In order to solve this technical problem, in one embodiment, multi-layer sputtering can be adjusted. In order to make the sputtering repaired pad reach the expected thickness, after the laser beam scans the metal film once, the position of the metal film is changed (the metal film tape is rotated to scan again at the new position of the metal film), so that the position of the metal film that has not been irradiated by the laser beam is moved to the position of the mask gap 101 for the next scan. In this embodiment, the position of the metal film is changed each time the metal film is sputtered, thereby ensuring that each sputtering produces droplets arranged according to the sputtering path, thereby achieving the expected sputtering effect.

[0126] In one embodiment, before the laser beam is controlled to move based on the sputtering path and the laser beam scans the metal film at least once, the parameters of the laser beam are adjusted to control the temperature distribution and solidification rate during the repair process, which is beneficial to optimize the microstructure of the deposited layer and further improve the bonding quality between the deposited layer and the substrate. The parameters of the laser beam include power density, scanning speed, etc.

[0127] In one embodiment, after the sputtering process is completed, the voice coil platform is lowered, the high-precision XY motion platform drives the substrate to move to the discharge position, and the roller rotates to send the substrate out.

[0128] The above-mentioned pad repair method is applied to ultra-thin pad repair compared to the laser induced transfer repair method. Among them, the metal droplets formed by the laser induced transfer repair method are larger, and it is easy to cause excessive metal deposition at the pad position during the metal transfer process. The laser sputtering process in the present invention repairs the damaged metal pad, and through the multi-axis motion platform driven by a servo motor and / or a high-speed scanning laser galvanometer, etc., it ensures that the position control can be achieved accurately to the micron level even in a very small space, which is very suitable for manufacturing ultra-thin pads.

[0129] The above-mentioned pad repair method can also be used to repair damaged circuits in non-pad areas of the substrate. The specific repair method is the same as the above-mentioned method and will not be described in detail here.

[0130] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A pad repair method, characterized in that: include: Acquire the bad spot information of the pad on the substrate, and determine the position of the pad to be repaired based on the bad spot information of the pad; According to the position of the pad to be repaired, a mask (10) is pressed onto the substrate so that the position of the pad to be repaired is exposed from the mask notch (101); Arranging a metal film at a position where the pad to be repaired is exposed from the mask gap (101); The metal on the metal film is melted and sputtered into nano droplets by laser sputtering, so that the nano droplets fall into the mask gap (101) and cover the position of the pad to be repaired to form a metal accumulation layer.

2. The pad repair method according to claim 1, characterized in that: The step of obtaining the bad pad information on the substrate and determining the position of the pad to be repaired based on the bad pad information includes: Setting a marking point on the substrate, and setting a two-dimensional code recording the bad point information of the pad corresponding to the substrate on the substrate; Load the substrate, scan the QR code on the substrate, obtain the bad pixel information contained in the QR code through the Internet and store it in the controller; The substrate is moved to the bottom of the visual recognition camera (12) by the motion platform (4), and the substrate is initially positioned by scanning the marking points on the substrate; based on the bad pixel information read, the motion platform (4) is controlled to move the substrate, and the position of the pad to be repaired is accurately positioned.

3. The pad repair method according to claim 1, characterized in that: The method comprises: pressing a mask (10) onto a substrate according to the position of the pad to be repaired, so that the position of the pad to be repaired is exposed from a mask notch (101), comprising: Based on the acquired position of the pad to be repaired, the substrate is driven to move horizontally by a motion platform (4) to align the mask gap (101) with the pad to be repaired; The substrate is driven to rise by the motion platform (4), so that the mask (10) presses the substrate tightly.

4. The pad repair method according to claim 3, characterized in that: Before the substrate is lifted by the motion platform (4), the height of the pad to be repaired is measured by a laser height measuring mechanism to obtain the required lifting position of the motion platform (4), and the lifting of the motion platform (4) is controlled based on the required lifting position of the motion platform (4); And / or, before aligning the mask gap (101) with the pad to be repaired, the position of the mask gap (101) is marked in advance by a bottom calibration camera (14).

5. The pad repair method according to any one of claims 1 to 4, characterized in that: The method of using a laser sputtering method to melt the metal on the metal film and sputter it into nano droplets comprises: Set the sputtering path; The movement of the laser beam is controlled based on the sputtering path so that the laser beam scans the metal film at least once; wherein the laser beam scans the metal film once means that the laser beam moves from the starting end of the sputtering path to the ending end of the sputtering path according to the set path.

6. The pad repair method according to claim 5, characterized in that: The sputtering path is set based on the scan time: The form of the sputtering path changes based on an increase in scanning time; Alternatively, the form of the sputtering path remains unchanged based on the increase in scanning time.

7. The pad repair method according to claim 6, characterized in that: The sputtering path is a reciprocating sputtering path, so that the laser beam is evenly irradiated onto the metal film; the reciprocating sputtering path is in the form of a vertical reciprocating sputtering path, a horizontal reciprocating sputtering path, or an inclined reciprocating sputtering path.

8. The pad repair method according to claim 5, characterized in that: The laser beam scans the metal film at least once, which is achieved by driving the picosecond laser generator (6) through the laser galvanometer (7); and the sputtering path is achieved by customizing the movement path of the laser galvanometer (7).

9. The pad repair method according to claim 5, characterized in that: After the laser beam scans the metal film once, the position of the metal film is changed so that the position of the metal film not irradiated by the laser beam moves to the position of the mask gap (101) so as to perform the next scan; And / or, before controlling the movement of the laser beam based on the sputtering path so that the laser beam scans the metal film at least once, adjusting the parameters of the laser beam to control the temperature distribution and solidification rate during the repair process.

10. The pad repair method according to any one of claims 1 to 4, characterized in that: The method can also be used to repair circuit damage in non-pad areas of the substrate.

11. A pad repair device, characterized in that: The pad repair device is based on the pad repair method according to any one of claims 1 to 10, comprising: A frame (1) having a mounting platform; A gantry (2) is arranged above the frame (1) and forms an operating space for performing repair operations between the gantry and the mounting platform of the frame (1); A motion platform (4) is arranged on the mounting platform and is used to drive the substrate to move in horizontal and vertical directions; A picosecond laser generator (6) is arranged on the gantry (2) and is used to emit a laser beam; A laser galvanometer (7), arranged on the gantry (2), and used for controlling the deflection of a laser beam emitted by a picosecond laser generator (6); A metal film roll releasing mechanism (8) is arranged on the gantry (2) and is located between the laser galvanometer (7) and the motion platform (4), and is used to release the metal film onto the mask (10); The clamping mechanism (9) is arranged on the gantry (2) and is used to clamp and position the mask (10) and the metal film.

12. The pad repairing device according to claim 11, characterized in that: The gantry (2) is also provided with a metal film rewinding mechanism (15). After the picosecond laser generator (6) completes scanning of the metal film each time, the metal film rewinding mechanism (15) controls the metal film to be rewinded so as to cover the gap of the mask (10) with a new metal film.

13. The pad repairing device according to claim 11 or 12, characterized in that: The pad repairing device also includes: A visual recognition camera (12) is arranged on the gantry (2) and is used to accurately locate the position of the pad to be repaired; and / or, a laser height sensor (13) is arranged on the gantry (2) and is used to detect the height of the substrate to be repaired, and cooperate with the motion platform (4) to rise to a corresponding height so as to cover the mask (10) onto the substrate; and / or, a bottom calibration camera (14), arranged on the motion platform (4), for calibrating the position of the notch of the mask (10), so that the notch of the mask (10) can be aligned with the pad to be repaired during processing; and / or, a buffer device (11), arranged on the clamping mechanism (9), for buffering the substrate when the mask (10) contacts the substrate, so as to prevent the mask (10) from damaging the substrate; And / or, a conveying and adsorption device (5) is used to convey the substrate between the feeding and discharging platform and the moving platform (4), and to adsorb and level the substrate.

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