A method and system for automatic dispensing of solder paste in a deep cavity circuit

Abstract

This invention belongs to the field of electronic manufacturing technology and discloses a method and system for automatically applying solder paste to deep cavity circuits. First, the solder paste in the syringe is subjected to constant temperature reheating and stirring to ensure its uniform flowability. A precision metal needle with an extended tip is selected, allowing it to penetrate deep into the circuit, solving the problem of ordinary needles being unable to reach the solder pads. By preset application pressure and time, combined with visual positioning and laser height measurement to determine the solder pad position, precise control of solder paste quantity, application position, and thickness is achieved. A negative pressure adsorption device prevents solder paste from splashing during non-working periods, reducing waste. Finally, SPI and X-ray inspection ensure quality. Compared to manual application, this method significantly improves the positional accuracy and consistency of solder paste application in deep cavity circuits, avoiding human error.

Description

Technical Field

[0001] This invention belongs to the field of electronic manufacturing technology, specifically a method and system for automatically applying solder paste to deep cavity circuits. Background Technology

[0002] As electronic products continue to upgrade towards miniaturization and lightweighting, MCM deep cavity circuit technology based on bare chip packaging has become a core technology for high-end electronic circuit manufacturing due to its advantages of high-density interconnection, electromagnetic shielding, and compatibility with high-frequency circuits.

[0003] The complex and unique structure of deep cavity circuits, with their deep holes and narrow cavities, makes conventional solder paste coating processes unsuitable for precise machining requirements, thus hindering the large-scale, high-quality production of deep cavity circuits.

[0004] Currently, the industry primarily addresses the challenge of solder paste application for deep cavity circuits by employing traditional manual dispensing processes. This method is adapted to the unique cavity structure of deep cavity circuits, compensating for the limitations of precise application achieved through stencil printing. However, the maturation of automation technologies such as robotics, visual recognition, and precision motion control provides solid technical support for the research and development and implementation of automated solder paste application solutions for deep cavity circuits. The industry is also exploring automated methods such as online programming, parameter adjustment, and needle adaptation to achieve batch and precise solder paste application for deep cavity circuits, thus contributing to the intelligent upgrading of electronic manufacturing.

[0005] The existing mainstream manual solder paste application process has poor overall practicality and adaptability, failing to meet the high-precision, consistent, and mass production requirements of high-end deep cavity circuits. Manual operation cannot precisely control the amount and location of solder paste application, heavily relying on the operator's professional skills. This not only significantly increases labor costs and reduces production efficiency, making it unsuitable for large-scale industrial production, but also makes it difficult to guarantee the consistency of solder paste application across batches. Furthermore, manual control has large errors, easily leading to excessive use of solder paste, and the solder paste is difficult to recycle after opening, resulting in significant material waste. Since solder paste application is a core process in deep cavity circuit assembly, defects in the coating quality directly cause problems such as cold solder joints, uneven coating, and positional misalignment, which in turn cause circuit signal distortion, increased power consumption, and even circuit failure, severely reducing soldering reliability and overall circuit performance. Summary of the Invention

[0006] This invention provides a method and system for automatically applying solder paste to deep cavity circuits, which solves the problems of low efficiency, poor consistency, and poor adaptability to deep cavities in existing manual application techniques.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for automatically applying solder paste to deep cavity circuits, comprising the following steps: Remove the solder paste from the refrigerator and place it in a constant temperature stirring device to warm it up and stir it evenly; then select a precision metal needle with an extended tip and install it onto the syringe. Set the dotting pressure, dotting time, and dotting path according to the size of the deep cavity circuit pads; The deep cavity circuit is placed in the mold, and the position of the solder pad is determined by visual positioning and laser height measurement. Solder paste is applied in batches through a syringe according to the set parameters. The quality of the circuit soldering is inspected using testing equipment. Once the inspection is passed, the spot coating is completed.

[0008] According to one embodiment of the present invention, the temperature of the constant temperature stirring device is 20-30°C and the stirring speed is 100-300 rpm.

[0009] According to one embodiment of the present invention, the needle diameter is 0.15-0.4 mm, and the length of the extended portion is 2 mm.

[0010] According to one embodiment of the present invention, the dotting pressure is 0.1-0.5 MPa and the dotting time is 0.1-0.5 s / dot.

[0011] According to one embodiment of the present invention, a negative pressure adsorption device is used to prevent solder paste from splashing during non-working state when performing batch spot application of solder paste.

[0012] According to one embodiment of the present invention, the detection device is an SPI and X-ray detection device.

[0013] The present invention also provides an automatic deep cavity circuit solder paste application system, and a method for implementing automatic deep cavity circuit solder paste application includes: A constant temperature stirring device is used to reheat and stir the syringe solder paste; an automatic solder paste application device includes a microcomputer-controlled air valve, a syringe dispenser, and a precision metal needle with an extended needle tip. The microcomputer-controlled air valve opens and closes, pressurizing the solder paste to be discharged from the syringe dispenser and applied to the solder pad. An online programming control unit, connected to the automatic solder paste application equipment, is used to control the shape, size, thickness, and position of the solder paste application. A visual positioning and laser height measurement module is used to determine the position of the deep cavity circuit pads; A negative pressure adsorption device is placed near the needle tip to prevent solder paste from splashing when not in use; Testing equipment is used to inspect the welding quality after spot coating.

[0014] According to one embodiment of the present invention, the negative pressure adsorption device is disposed at the needle outlet.

[0015] According to one embodiment of the present invention, the positioning accuracy of the visual positioning and laser altimeter module is ±0.01mm.

[0016] According to one embodiment of the present invention, the detection device is an SPI detection device or an X-ray detection device.

[0017] Compared with existing technologies, this invention has the following advantages: This invention provides an automatic dispensing method for deep cavity circuit solder paste. The solder paste in the syringe is heated to a constant temperature to ensure uniform flowability. A precision metal needle with an extended tip is used, allowing it to penetrate deep into the circuit, solving the problem of ordinary needles being unable to reach the solder pads. By preset dispensing pressure and time, combined with visual positioning and laser height measurement to determine the solder pad position, precise control of solder paste quantity, application position, and thickness is achieved. A negative pressure adsorption device prevents solder paste from splashing during non-working states, reducing waste. Finally, SPI and X-ray inspection ensure quality. Compared with manual dispensing, this method significantly improves the positional accuracy and consistency of deep cavity circuit solder paste application, avoiding human error. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of a method for automatically applying solder paste to a deep cavity circuit according to the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," and "set up" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components.

[0024] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, this embodiment of the invention provides a method for automatic application of solder paste to deep cavity circuits, comprising the following steps: S1: Remove the syringe solder paste from the refrigerator and place it in a constant temperature stirring device to warm it up and stir it evenly; select a precision metal needle with an extended needle tip and install it onto the syringe. S2: Set the dotting pressure, dotting time, and dotting path according to the size of the deep cavity circuit pads; S3: Place the deep cavity circuit in the mold, determine the position of the solder pads by visual positioning and laser height measurement, and apply solder paste in batches through a syringe according to the set parameters; S4: The circuit soldering quality is inspected using testing equipment. If the inspection is qualified, the spot coating is completed.

[0026] The solder paste is stirred at a constant temperature to ensure its uniform flowability. A precision metal needle with an extended tip is used, allowing it to penetrate deep into the circuitry and solving the problem of ordinary needles being unable to reach the pads. By pre-setting the application pressure and time, combined with visual positioning and laser height measurement to determine the pad positions, precise control of the solder paste quantity, application location, and thickness is achieved. A negative pressure adsorption device prevents solder paste from splashing during non-operational periods, reducing waste. Finally, SPI and X-ray inspection ensure quality. Compared to manual application, this method significantly improves the positional accuracy and consistency of solder paste application in deep-cavity circuits, avoiding human error.

[0027] The detailed steps are as follows: S1: Solder paste pretreatment Remove the syringe solder paste from the refrigerator (usually 2-8℃) and place it in a thermostatic stirring device. Maintain the device temperature at 20-30℃ and the stirring speed at 100-300 rpm to allow the solder paste to warm up evenly and restore its suitable fluidity and thixotropic properties. This prevents excessive viscosity and poor dispensing due to low solder paste temperature, or separation of solder paste components due to uneven stirring, thus ensuring consistent subsequent dispensing and effective pad wetting.

[0028] S2: Needle Selection Based on the cavity depth and pad size of the deep cavity circuit, select a precision metal needle with an extended tip (needle diameter range 0.15-0.4mm, extension length 2mm). Mount the selected needle onto the syringe dispenser. The extended needle can penetrate into cavities up to 2mm deep, ensuring solder paste is applied directly to the bottom pads of the cavity, preventing the needle from colliding with the cavity wall or solder paste from splashing onto non-target areas. This step solves the key technical problem of traditional needles being unable to reach deep cavity pads.

[0029] S3: Dot Painting Parameter Settings Depending on the size of the deep cavity circuit pads (e.g., 0402 / 0603 / 0805 resistor-capacitor pads or 200μm BGA pads), the dispensing pressure, dispensing time, and dispensing path are set via an online programming control unit. The preferred dispensing pressure is 0.1-0.5MPa, and the preferred dispensing time is 0.1-0.5s / particle. The dispensing path is automatically generated by software based on the pad layout or manually taught. Precise control of air pressure and time allows for accurate distribution of solder paste to each pad, preventing insufficient solder or solder overflow.

[0030] S4: Dotting operation Multiple deep-cavity circuits are placed in a dedicated mold in batches. A high-precision vision positioning system identifies the coordinates of the solder pads, and a laser height measurement module measures the vertical distance between the bottom of the cavity and the needle tip, automatically compensating for height deviations. Then, according to preset parameters, a microcomputer controls the opening and closing of air valves, pressurizing the solder paste to be discharged from the syringe through the needle tip and applied point by point to the solder pads. Simultaneously, a negative pressure adsorption device (located near the needle tip) continuously evacuates air during non-application periods to prevent solder paste from splashing due to gravity or residual pressure dripping. This step achieves batch, automated, high-precision application, significantly improving production efficiency.

[0031] S5: Dot application effect test After the solder paste application is completed, the solder paste quantity, positional offset, bridging, and missing areas of the circuit are inspected using an SPI (solder paste thickness meter) and X-ray inspection equipment to ensure soldering reliability. The inspection data can be fed back to the online programming control unit for parameter optimization.

[0032] The present invention also provides an automatic solder paste application system for deep cavity circuits, for implementing the above method.

[0033] The system includes: Thermostatic stirring device: used to reheat and stir the syringe solder paste to ensure that the solder paste is in a uniform state.

[0034] Automatic solder paste application equipment: includes a microcomputer-controlled air valve, a syringe dispenser, and a precision metal needle with an extended tip (extended length 2mm, diameter 0.15-0.4mm). The microcomputer controls the opening and closing of the air valve, pressurizing the system to discharge solder paste from the syringe dispenser and apply it to the solder pads.

[0035] Online programming control unit: Connected to the automatic solder paste application equipment, it is used to set and control the shape, size, thickness, position, and application path of the solder paste.

[0036] Visual positioning and laser height measurement module: used to determine the precise position and height of the deep cavity circuit pads, with a positioning accuracy of ±0.01mm.

[0037] Negative pressure adsorption device: Located near the needle tip outlet (preferably on the side of the needle tip outlet or a ring-shaped nozzle), it generates negative pressure when not applying the coating, drawing away residual solder paste from the needle tip to prevent dripping and contaminating the product.

[0038] Inspection equipment: SPI inspection equipment or X-ray inspection equipment, used to inspect the welding quality after spot coating.

[0039] The workflow of the above system is as follows: The operator puts the refrigerated solder paste into a constant temperature stirring device to complete the rewarming process; the rewarmed syringe is installed on the dotting equipment, and a suitable extended needle is selected; the pad layout diagram is imported into the programming control unit, and the dotting parameters are set; the mold containing the batch deep cavity circuit is placed on the worktable, and the automatic dotting program is started; the vision and laser modules sequentially locate the pads of each cavity, and the equipment coats the substrate point by point along the path; after coating is completed, the substrate enters the inspection station for SPI and X-ray sampling inspection; qualified products enter the subsequent surface mount and reflow soldering processes.

[0040] The implementation process and effects of the present invention are further illustrated below with reference to two specific embodiments.

[0041] Example 1 This embodiment provides a method for automatically applying solder paste to a deep-cavity hybrid integrated circuit. The circuit has external dimensions of 25.3×25.3×5.2mm, a cavity depth of 2.0mm, and requires solder paste application to 0402 / 0603 / 0805 resistor-capacitor pads.

[0042] Specific steps: (1) Solder paste pretreatment: Take the syringe solder paste out of the refrigerator and place it in a constant temperature stirring device. Set the temperature to 25℃, the stirring speed to 200rpm, and the time to 15min.

[0043] (2) Needle selection: Select a precision metal needle with a 2mm longer tip and a diameter of 0.25mm, and install it on the syringe.

[0044] (3) Setting of dispensing parameters: dispensing pressure 0.3MPa, dispensing time 0.2s / point, and the path is automatically generated by the software based on the pad coordinates.

[0045] (4) Spot coating operation: Place 10 circuit pieces into the mold in batch, visually locate and identify all pads, use laser height measurement to compensate for height difference, and start automatic spot coating. The negative pressure adsorption device is on throughout the process.

[0046] (5) Spot coating effect test: SPI test showed that the thickness deviation of each pad solder paste was <15%, and X-ray test showed no bridging and no voids.

[0047] Example 2 This embodiment provides another method for automatically applying solder paste to deep cavity hybrid integrated circuits. The circuit has an outline size of 770mm (elongated substrate), a step depth of 2.0mm, and requires 200μm BGA pads for soldering.

[0048] Specific steps: (1) Solder paste pretreatment: Take the syringe solder paste out of the refrigerator and place it in a constant temperature stirring device. Set the temperature to 25℃, the stirring speed to 200rpm, and the time to 15min.

[0049] (2) Needle selection: Select a precision metal needle with a 2mm longer tip and a diameter of 0.18mm.

[0050] (3) Setting of dotting parameters: dotting pressure 0.2MPa, dotting time 0.1s / dotting, and path set according to BGA array order.

[0051] (4) Spot coating operation: Place the substrate on the vacuum adsorption platform, visually locate all pads, use laser height measurement to compensate for substrate warping, and coat the substrate point by point.

[0052] (5) Spot coating effect test: X-ray inspection showed that the position of solder paste was offset by <15μm, the amount of solder was uniform, and there was no insufficient solder or solder bridging.

[0053] In this embodiment, automatic spot coating ensures the consistency of solder paste amount for each BGA solder joint, significantly reducing cold solder joints or short circuits caused by uneven manual coating.

[0054] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0055] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for automatic dispensing of deep cavity circuit solder paste, characterized in that, Includes the following steps: Remove the syringe solder paste from the refrigerator and place it in a constant temperature stirring device to warm it up and stir it evenly. Select a precision metal needle with an extended tip and install it onto the syringe; Set the dotting pressure, dotting time, and dotting path according to the size of the deep cavity circuit pads; The deep cavity circuit is placed in the mold, and the position of the solder pad is determined by visual positioning and laser height measurement. Solder paste is applied in batches through a syringe according to the set parameters. The quality of the circuit soldering is inspected using testing equipment. Once the inspection is passed, the spot coating is completed.

2. The method for automatic dispensing of deep cavity circuit solder paste according to claim 1, characterized in that, The temperature of the constant temperature stirring device is 20-30℃, and the stirring speed is 100-300rpm.

3. The method of claim 1, wherein the method further comprises: The needle diameter is 0.15-0.4mm, and the extended part is 2mm long.

4. The method of claim 1, wherein the method further comprises: The dotting pressure is 0.1-0.5 MPa, and the dotting time is 0.1-0.5 s / dot.

5. The method of claim 1, wherein the method further comprises: A negative pressure adsorption device is used to prevent solder paste from splashing when not in operation during batch application of solder paste.

6. The method of claim 1, wherein, The testing equipment consists of SPI and X-ray testing equipment.

7. An automatic dispensing system for deep cavity circuit solder paste, characterized in that, A method for automatically applying solder paste to a deep cavity circuit according to any one of claims 1-6 includes: A constant temperature stirring device is used to reheat and stir the syringe solder paste; The automatic solder paste application equipment includes a microcomputer-controlled air valve, a syringe dispenser, and a precision metal needle with an extended needle tip. The microcomputer-controlled air valve opens and closes, pressurizing the solder paste to be discharged from the syringe dispenser and applied to the solder pads. An online programming control unit, connected to the automatic solder paste application equipment, is used to control the shape, size, thickness, and position of the solder paste application. A visual positioning and laser height measurement module is used to determine the position of the deep cavity circuit pads; A negative pressure adsorption device is placed near the needle tip to prevent solder paste from splashing when not in use; Testing equipment is used to inspect the welding quality after spot coating.

8. The system of claim 7, wherein, The negative pressure adsorption device is located at the needle outlet.

9. The system of claim 7, wherein, The positioning accuracy of the visual positioning and laser height measurement module is ±0.01mm.

10. The system of claim 7, wherein, The detection equipment is either an SPI detection device or an X-ray detection device.

Images