Welding method of perforated bonding pad and power supply module

Abstract

The invention relates to the technical field of printed circuit boards, in particular to a welding method of a bonding pad with a hole and a power module, in the process of coating a welding material, the hole area on the bonding pad is shielded, it is ensured that the welding material is only coated on the specified welding area, the welding material is effectively prevented from entering the hole area, and meanwhile the welding material is prevented from entering the hole area. The protection area coating on the periphery of the hole opening area can further prevent the welding material from entering the hole opening area, so that the holes in the bonding pad are not affected by the welding material, and the circuit board damage and reworking problems caused by the fact that the welding material enters the hole opening area mistakenly are reduced. Besides, the welding material does not enter the trepanning area, so that the welding material of the bonding pad is not lost, the risks of pseudo soldering, tombstone standing and the like can be avoided, and the production and product costs are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of printed circuit boards, and in particular to a welding method for a soldering pad with an opening and a power module. Background Art

[0002] The soldering pad is a conductive or thermally conductive soldering surface area on a printed circuit board (PCB), which is specially designed to be soldered to the pins or terminals of electronic components, and can provide electrical connections between electronic components and other circuit parts on the PCB. For surface mount components, especially in high-power and high-current products, the heat dissipation pad area of ​​power devices is generally larger, and more heat dissipation through-holes are usually required in the soldering pad, so the soldering pad needs to match the solder paste and mounting accuracy to ensure that good solder joints are formed during the reflow process.

[0003] Considering the processing cost, multilayer boards on PCB generally adopt through-hole or blind-hole design. In the following, through-hole and blind-hole are collectively referred to as openings. When the opening is designed on the pad, such as Figure 1 Specifically, if solder paste enters the opening (such as Figure 1 The existing conventional soldering process is to directly apply soldering materials (such as solder paste) on the pad, and then reflow soldering. Such an operation process will inevitably cause soldering materials to enter the opening, leading to the above problems.

[0004] In view of this, overcoming the defects of the prior art is an urgent problem to be solved in the field of this technology. Summary of the invention

[0005] The technical problem to be solved by the present invention is how to prevent welding material from entering the opening during the welding process between the welding element and the welding pad.

[0006] The present invention adopts the following technical solution:

[0007] In a first aspect, a welding method for a soldering pad with an opening is provided, wherein the soldering pad with an opening comprises a welding area and an opening area, and the method comprises:

[0008] Coating a protective material on the periphery of the opening area to form a protective area coating;

[0009] The protective area coating and the opening area are shielded, and the welding material is coated on the welding area;

[0010] A welding element is placed on the welding area, and the welding element is welded to the welding area through a welding process.

[0011] Preferably, the coating of welding material in the welding area comprises:

[0012] A welding coating template is provided, and the welding coating template is provided on the welding pad, and the welding material is coated on the welding area through the welding coating template.

[0013] Preferably, the step of setting a welding coating template, setting the welding coating template on the welding pad, and coating the welding material on the welding area through the welding coating template comprises:

[0014] A welding coating template having a size matching that of the welding pad is provided; wherein the welding coating template is provided with a hollow area matching that of the welding area;

[0015] The welding coating template is arranged on the welding pad, and the hollow area is aligned with the welding area, so that the welding area is completely exposed, and the coating of the opening area and the protection area is completely shielded;

[0016] The coating of the welding material of the welding area is completed through the welding coating template.

[0017] Preferably, the step of setting a welding coating template, setting the welding coating template on the welding pad, and coating the welding material on the welding area through the welding coating template further comprises:

[0018] Mounting the solder coating template on a solder coating machine and aligning the solder coating template with the solder pad;

[0019] Controlling a scraper on the welding coating machine to move on the welding coating template at a preset pressure and a preset angle, and printing the welding material to the welding area on the pad through the hollow area on the welding coating template to complete the coating of the welding material on the pad;

[0020] Wherein, the preset speed and preset pressure of the scraper are set according to the distance between the welding coating template and the welding pad.

[0021] Preferably, the coating of welding material in the welding area further comprises:

[0022] A welding ejector pin template is provided, and the welding ejector pin template is provided on the welding pad, and the welding area is coated with welding material through the welding ejector pin template.

[0023] Preferably, the step of providing a welding ejector template, providing the welding ejector template on the welding pad, and applying welding material to the welding area through the welding ejector template comprises:

[0024] A soldering ejector pin template having a size matching that of the soldering pad is provided; wherein the soldering ejector pin template is provided with a shielding ejector pin corresponding to the protective area coating and the opening area, and the shielding ejector pin can move up and down relative to the soldering ejector pin template;

[0025] Applying welding material on the welding ejector pin template, pushing the shielding ejector pin so that the shielding ejector pin protrudes from the welding ejector pin template, and removing the welding material on the shielding ejector pin;

[0026] The welding ejector pin template is placed directly above the welding pad, the shielding ejector pin supports the protective area coating and the opening area, the welding ejector pin template is moved downward, and other parts of the welding ejector pin template with welding material are brought into contact with the welding pad to apply the welding material to the welding area.

[0027] Preferably, the coating of welding material in the welding area further comprises:

[0028] An air blowing device is arranged on the back side corresponding to the opening area;

[0029] The blowing direction of the blowing device is directed from the non-coated surface on the pad to the coated surface. During the coating process of the welding material, the blowing device is turned on, and gas in the opening area is blown toward the coated surface on the pad to prevent the welding material from entering the opening area.

[0030] Preferably, the coating of welding material in the welding area further comprises:

[0031] Use a welding printer to print welding material evenly in the welding area; control the amount of welding material applied to form welding spots on the surface of the pad, avoid directly applying welding material on the pad, so as to complete the coating of welding material in the welding area.

[0032] Preferably, the shape of the protective area coating is circular, square or irregular. In a second aspect, a power module with a perforated pad is provided, the power module is obtained according to the welding method with a perforated pad described in the first aspect, and the power module includes: a circuit board and a welding element welded on the circuit board;

[0033] A soldering pad with an opening is arranged on the circuit board, and the soldering element is soldered on the soldering pad by using the soldering method of the soldering pad with an opening.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] In the present invention, during the coating of the welding material, the opening area on the pad is shielded to ensure that the welding material is only coated on the designated welding area, effectively preventing the welding material from entering the opening area. At the same time, the protective area coating outside the opening area can further prevent the welding material from entering the opening area, so that the opening on the pad is not affected by the welding material, reducing the damage and rework of the circuit board caused by the welding material mistakenly entering the opening area. In addition, the welding material will not enter the opening area, ensuring that the welding material of the pad will not be lost, avoiding the risks of false welding and tombstone, and reducing the production and product costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 It is a schematic diagram of the problem of tin entering the opening on the pad existing in the prior art;

[0038] Figure 2 It is a schematic flow chart of a welding method for a welding pad with a hole provided by an embodiment of the present invention;

[0039] Figure 3 It is a schematic diagram of a welding material coating process of a welding coating template provided by an embodiment of the present invention;

[0040] Figure 4 It is a structural schematic diagram of a welding coating template provided by an embodiment of the present invention;

[0041] Figure 5 It is another schematic diagram of a welding material coating process of a welding coating template provided by an embodiment of the present invention;

[0042] Figure 6 It is a schematic diagram of a welding material coating process of a welding ejector template provided by an embodiment of the present invention;

[0043] Figure 7 It is a state schematic diagram of a welding ejector template provided by an embodiment of the present invention;

[0044] Figure 8 This is a schematic diagram of another state of a welding ejector template provided by an embodiment of the present invention;

[0045] Fig. 9 This is a conventional coating effect diagram of a pad;

[0046] Fig.10 This is a coating effect diagram of a solder pad provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as open inclusion, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "examples", "specific examples" or "some examples" and the like are intended to indicate that specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner, that is, although they may be carried in the embodiments or examples of the above terms due to reasons such as the order and position of appearance, it is not limited to that they can be carried in combination by one embodiment or example.

[0049] In the description of the present invention, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, the meaning of "multiple" is two or more. In addition, for example, the same type of nouns may be described as two independent individuals by adding "A" and "B" at the end. In this case, the corresponding features defined as "A" and "B" are only used to distinguish the same type of individuals for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features.

[0050] When describing some embodiments, the expressions "coupling", "coupling" and "connection" and their derivatives may be used. For example, when describing some embodiments, the term "connection" may be used to indicate that two or more components are in direct physical or electrical contact with each other. For another example, when describing some embodiments, the term "coupling" may be used to indicate that two or more components are in direct physical or electrical contact. However, the terms "connection" or "coupling" may also refer to two or more components that are not in direct contact with each other, but still cooperate or interact with each other, such as "optical path coupling", "wireless connection", etc. The embodiments disclosed herein are not necessarily limited to the contents of the present invention.

[0051] In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0052] Embodiment 1:

[0053] The pad described as “the opening is designed just on the pad” is hereinafter referred to as a pad with an opening. The pad with an opening includes a welding area and an opening area. In a conventional welding process, welding material will enter the opening area on the pad, thereby causing a series of problems. In order to avoid the welding material from entering the opening area on the pad, this embodiment provides a welding method for a pad with an opening, such as Figure 2 As shown, the method includes:

[0054] Step 101: coating a protective material on the periphery of the opening area to form a protective area coating.

[0055] Among them, the opening area specifically refers to the opening on the pad. Protective material is arranged around the opening on the pad to form a protective area coating. The coating area of ​​the protective material is determined according to the actual welding requirements, and this embodiment does not make any specific limitations.

[0056] The opening on the pad may be a through hole penetrating the pad or a blind hole not penetrating the pad.

[0057] The protective area coating can effectively prevent the welding material from mistakenly entering the opening area in subsequent operations. The selection of protective materials should have the following characteristics: good adhesion, can be firmly attached to the surface of the pad; have a barrier property to the welding material to prevent the welding material from penetrating; can remain stable during the welding process and will not fail due to factors such as high temperature.

[0058] In one embodiment, the protective material is a polymer or a solder resist. The shape of the protective area coating is circular, square or irregular. The protective material coating needs to evenly cover the periphery of the opening area and ensure that the thickness is moderate, so as to effectively prevent the welding material from entering the opening area and not affect the subsequent welding operation of the welding element.

[0059] Step 102: shielding the protective area coating and the opening area, and coating the welding material in the welding area.

[0060] In the coating process of the welding material, in order to prevent the welding material from entering the opening area, a physical barrier can be formed by shielding the protective area coating and the opening area, thereby reducing the risk of the welding material entering the opening.

[0061] Although shielding is performed in advance, the welding material will flow toward the opening area when it has not yet solidified. When it flows into the protective area coating, the protective area coating can prevent the welding material from continuing to flow, thereby further preventing the welding material from entering the opening.

[0062] Step 103: placing a welding element on the welding area, and welding the welding element to the welding area through a welding process.

[0063] In one embodiment, after the welding material is coated on the welding area, a welding element is placed on the welding area, a fixing aid or auxiliary material is used to fix the relative position between the welding element and the welding area, and the welding element and the welding area are welded by a welding process.

[0064] After the welding material is applied to the welding area, the opening area on the pad is subjected to visual inspection or X-ray inspection of the welding material coating to ensure that no welding material enters the opening. If there is any residual welding material entering the opening, it can be cleaned and repaired. Then the welding component is accurately placed on the welding area on the pad to ensure that the pins of the welding component are in good contact with the welding material. A fixing aid (such as a clamp) or auxiliary material (such as a fixing glue) is used to fix the relative position of the welding component and the welding area on the pad to prevent the welding component from moving and causing dislocation during the welding process. Finally, a suitable welding process such as reflow soldering is used to weld the welding component (such as a power device, a heat sink or a heat dissipation backplane, etc.) to the pad.

[0065] After soldering components, check the firmness of the soldering and the electrical properties of the circuit board to ensure that the solder joints are firm and the openings are not blocked by soldering material, and then clean and repair them if necessary.

[0066] In this embodiment, during the coating of the soldering material, the opening area on the pad is shielded to ensure that the soldering material is only coated on the designated soldering area, effectively preventing the soldering material from entering the opening area. At the same time, the protective area coating outside the opening area can further prevent the soldering material from entering the opening area, so that the opening on the pad is not affected by the soldering material, reducing the damage to the circuit board and rework caused by the soldering material mistakenly entering the opening area. In addition, ensuring that the soldering material of the pad does not leak can avoid risks such as cold soldering and tombstone formation, and reduce production and product costs.

[0067] This embodiment proposes two solutions for shielding the opening area during the coating process of the welding material, and the two solutions are independent of each other.

[0068] The first solution is to set a welding coating template, set the welding coating template on the welding pad, and coat the welding material on the welding area through the welding coating template.

[0069] In one embodiment, Figure 3 As shown, there are two methods of using the welding coating template in the first scheme, wherein the manufacturing methods of the welding coating template are the same, and the first method of using the welding coating template specifically includes:

[0070] Step 1021: Setting a welding coating template whose size matches the welding pad; wherein the welding coating template is provided with a hollow area matching the welding area.

[0071] Among them, a suitable material is selected to make the welding coating template, and a material with a certain hardness and heat resistance is usually selected to ensure that it will not be easily deformed or damaged during subsequent processing and use. The size of the welding coating template matches the pad, which means that the shape of the welding coating template is consistent with that of the pad, and the area of ​​the welding coating template can be greater than or equal to the area of ​​the pad, so as to ensure that in the subsequent design, the welding coating template accurately covers the protective area coating and the opening area on the pad. The corresponding welding area on the welding coating template is hollowed out so that when the welding coating template is set on the pad, the welding area is completely exposed, and the opening area and the protective area coating are completely shielded.

[0072] like Figure 4As shown, the production process of the welding coating template includes: selecting a first template, finding a hollow area corresponding to the welding area on the first template, and hollowing out the hollow area using a professional hollowing process, which can be laser cutting, punching and other processes, to ensure that the shape and size of the hollowing are completely consistent with the welding area, and other non-hollowing areas are not processed to obtain a welding coating template. The hollowing process must ensure that the welding area is completely exposed, without any part being blocked or residual material, so that when the welding coating template is used, the welding area can be directly exposed for the coating of welding materials.

[0073] exist Figure 4 In the figure, the black area is the shielding area (i.e., the non-hollowing area mentioned above), and the white area is the hollowing area. The shielding area covers the protective area coating and the opening area to ensure that the protective area coating and the opening area are completely shielded to prevent the welding material from accidentally entering the opening area during the welding material coating process.

[0074] In one embodiment, the welding coating template can be a tin-planting mesh template, and the area corresponding to the welding area on the tin-planting mesh template is hollowed out, and the area corresponding to the protective area coating and the opening area on the tin-planting mesh template is shielded.

[0075] Step 1022: Set the welding coating template on the welding pad, align the hollow area with the welding area, so that the welding area is completely exposed, and the opening area and the protective area coating are completely shielded; complete the coating of the welding material in the welding area through the welding coating template.

[0076] In one embodiment, the welding coating template is disposed on the welding pad so that the welding area on the welding pad is completely exposed; while the opening area and the protective area coating on the welding pad are completely shielded, thereby playing an effective protective role.

[0077] Specifically, when placing the solder coating template on the solder pad, it is necessary to ensure that the hollow area on the solder coating template completely corresponds to the soldering area. This can be achieved by using positioning tools or reference marks to ensure that the hollow area on the template accurately covers the soldering area, and the shielding area also closely covers the protective area coating and the opening area.

[0078] According to the properties and requirements of the welding materials, choose the appropriate coating tool. For example, for solder wire, you can use a solder pen or soldering iron for coating; for solder paste, you can use a printer or syringe for coating.

[0079] Use a coating tool to coat the welding material. When coating the welding material, control the coating amount to avoid too much or too little welding material. Too much welding material may cause problems such as poor welding and short circuit; too little welding material may cause problems such as loose welding and poor contact. At the same time, to ensure that the welding material is evenly distributed on the welding area, you can achieve this by coating multiple times or adjusting the angle and speed of the coating tool.

[0080] After the welding material is applied, wait for the welding material to solidify before removing the welding coating template.

[0081] In one embodiment, Figure 5 As shown, the second method of using the welding coating template includes:

[0082] Step 10231: Install the welding coating template on the welding coating machine, and align the welding coating template with the welding pad.

[0083] Among them, the direction and position of the welding coating template should be paid attention to during the installation process of accurately installing the welding coating template on the welding coating machine to ensure coordination with other parts of the welding coating machine. The welding coating template is completely aligned with the pad by adjusting the position and angle of the welding coating machine. A visual system or positioning sensor can be used to assist in alignment to ensure that the hollow area on the welding coating template corresponds accurately to the welding area on the pad.

[0084] Step 10232: Control the scraper on the welding coating machine to move on the welding coating template at a preset pressure and a preset angle, and print the welding material to the welding area on the pad through the hollow area on the welding coating template to complete the coating of the welding material on the pad.

[0085] Wherein, the preset speed and preset pressure of the scraper are set according to the distance between the welding coating template and the welding pad.

[0086] The preset pressure of the scraper is set according to the distance between the welding coating template and the pad. When the distance is close, the pressure can be appropriately reduced to avoid excessive pressure on the template and the pad; when the distance is far, the pressure needs to be appropriately increased to ensure that the welding material can be smoothly printed on the pad through the hollow area. The setting of the pressure requires multiple tests and adjustments to find the most suitable parameters. The angle of the scraper also has an important influence on the coating effect. The appropriate angle can ensure that the welding material is evenly distributed on the welding area and does not leave too much welding material on the template. The setting of the angle needs to consider factors such as the nature of the welding material, the material and thickness of the template. The preset speed of the scraper is set according to the distance between the welding coating template and the pad and the characteristics of the welding material.

[0087] The scraper on the solder coating machine is controlled to move on the solder coating template at a preset pressure, angle and speed. During the movement, the scraper pushes the solder material to the hollow area on the solder coating template, so that the solder material is printed through the hollow area to the soldering area on the pad.

[0088] In one embodiment, a second method for shielding the opening area during the coating process of the welding material is:

[0089] A welding ejector pin template is provided, and the welding ejector pin template is provided on the welding pad, and the welding area is coated with welding material through the welding ejector pin template.

[0090] Specifically, Figure 6 As shown, the second solution includes:

[0091] Step 201: Setting a soldering ejector template whose size matches the solder pad; wherein the soldering ejector template is provided with shielding ejectors corresponding to the protective area coating and the opening area, and the shielding ejectors can move up and down relative to the soldering ejector template.

[0092] Among them, materials with certain hardness and heat resistance are usually selected as welding ejector pin templates to ensure that they will not be easily deformed or damaged during subsequent processing and use. The size of the welding ejector pin template matches the pad, which means that the shape of the welding ejector pin template is consistent with that of the pad, and the area of ​​the welding ejector pin template can be greater than or equal to the area of ​​the pad.

[0093] A second template is selected, and a shielding ejector pin that can move up and down is set on the second template corresponding to the protective area coating and the opening area on the pad to obtain the welding ejector pin template.

[0094] In one embodiment, Figure 7 As shown, according to the positions of the protective area coating and the opening area on the pad, shielding pins are accurately set on the second template, and the number of the shielding pins should match the number of openings on the pad so as to cover each opening area.

[0095] In order to ensure that the shielding ejector pin can completely cover the opening area during the coating process, the diameter of the shielding ejector pin should be greater than or equal to the aperture of the opening. The position of the shielding ejector pin completely corresponds to the opening area to ensure that the opening area can be effectively covered in subsequent operations. The shielding ejector pin is designed to be movable up and down, and can be moved up and down by mechanical devices, air pressure or hydraulic systems, etc. The specific implementation method will not be described in detail in this embodiment.

[0096] Step 202: coating the welding material on the welding ejector pin template, pushing the shielding ejector pin to make the shielding ejector pin protrude from the welding ejector pin template, and removing the welding material on the shielding ejector pin.

[0097] Use appropriate coating methods such as spraying, printing or manual application to apply the welding material to the Figure 7 The coated surface of the welding ejector template in the state shown. When applying, make sure that the welding material is evenly distributed on the template and has appropriate thickness.

[0098] Since there should be no welding material on the surface of the shielding ejector pin, after the welding material is applied, the shielding ejector pin is pushed upward (such as Figure 8 As shown), the shielding ejector pin is made to protrude from the welding ejector pin template, and the welding material on its surface is removed by a scraper auxiliary tool.

[0099] Step 203: Place the welding ejector pin template directly above the welding pad, with the shielding ejector pin supporting the protective area coating and the opening area, move the welding ejector pin template downward, and make other parts of the welding ejector pin template with welding material contact with the welding pad to apply welding material to the welding area.

[0100] After removing the welding material on the shielding ejector pin on the welding ejector pin template, place the welding ejector pin template directly above the pad. When the welding ejector pin template is placed, the shielding ejector pin extends to support the protective area coating and the opening area on the pad. The extension force of the shielding ejector pin should be moderate, so that it can firmly support the pad without damaging the pad. As the shielding ejector pin extends, other parts with welding material on the coating surface of the welding ejector pin template come into contact with the pad. Due to the shielding effect of the ejector pin, the welding material can only be applied to the welding area on the pad. This ensures the accurate application of the welding material and avoids the mistaken entry into the protective area coating and the opening area.

[0101] In one embodiment, the pad can be divided into multiple parts according to the size of the pad and the actual situation, and the same opening area can be divided into one part. The above two solutions for shielding the opening area can be performed on each part respectively. The specific implementation process can be simply deduced from the above two solutions, and will not be described in detail in this embodiment.

[0102] Both of the above-mentioned solutions for shielding the opening area require redesigning the corresponding templates. Although the shielding effect is relatively good, it undoubtedly increases the steps of making and using the two templates. When the opening is a through hole, in order to achieve the effect of shielding the opening area while simplifying the coating steps of the welding material, a solution is also provided for blocking the welding material from entering the opening area through airflow.

[0103] In one embodiment, a blowing device is provided on the back side corresponding to the opening area; the blowing direction of the blowing device is directed from the non-coated surface on the pad to the coated surface; the blowing device is turned on during the coating process of the welding material, and gas in the opening area is blown toward the coated surface on the pad to prevent the welding material from entering the opening area.

[0104] In one embodiment, a plurality of blowing devices are provided for the non-coated surface of the pad, and each opening area corresponds to a blowing device, so that precise blowing operation can be performed for each opening area to ensure that each opening can be effectively protected. The blowing device can be a small air pump or a compressed air nozzle, etc., and its size should be adapted to the opening so that it can be installed on the back of the opening. When installing the blowing device, ensure that it is positioned accurately and the blowing direction can be directly directed to the coated surface on the pad. At the same time, the stability of the blowing device must be ensured to avoid movement or loosening during the welding process.

[0105] Another way is to set a larger blowing device on the non-coated surface of the pad to cover all the opening areas. This method can simplify the setting of the blowing device, but it is necessary to ensure that the blowing device can evenly blow gas to each opening area to prevent the welding material from entering the opening area.

[0106] In actual use, the blowing direction of the blowing device is directed from the non-coated surface of the pad to the coated surface, and during the coating process of the welding material, an airflow from the inside of the opening to the outside is formed. When the welding material has a tendency to enter the opening, this airflow can prevent the welding material from entering and blow out the small amount of welding material that has entered the opening.

[0107] From the beginning of coating the welding material, the blowing device is controlled to be in working state, and the gas is continuously blown into the opening area. This can prevent the welding material from entering the opening in real time, and improve the quality and reliability of welding. The operator needs to reasonably control the airflow intensity and duration of the blowing device according to the progress and situation of coating. If the airflow intensity is too large, it may affect the coating effect of the welding material in the welding area; if the airflow intensity is too small, it may not be able to effectively prevent the welding material from entering the opening area.

[0108] By setting an air blowing device on the non-coated surface of the pad and correctly controlling the blowing direction and operation timing during the welding material coating process, an effect similar to shielding the opening area can be achieved, and the welding material entering the opening area can be effectively removed, ensuring the smooth progress of the welding process and improving the welding quality.

[0109] In one embodiment, the coating of the welding material in the welding area also includes: using a welding printer to evenly print the welding material in the welding area; controlling the amount of welding material applied to form a welding spot on the surface of the pad, avoiding directly applying the welding material on the pad, so as to complete the coating of the welding material in the welding area.

[0110] The welding printer can accurately locate the welding area of ​​the pad according to the preset program. Through advanced sensors and positioning systems, it is ensured that the welding material can be accurately printed at the specified position, avoiding errors that may be caused by manual operation. The welding printer can finely adjust the printing parameters, such as printing speed, output of welding materials, etc. This enables uniform distribution of welding materials on the welding area, providing a good foundation for subsequent welding operations. In one embodiment, the welding printer can be a UV (full name in English: Ultraviolet) printer.

[0111] Spot welding technology allows precise control of the amount of welding material applied. By setting appropriate welding parameters, such as current, voltage and welding time, uniform and regular-shaped welding spots can be formed on the surface of the pad. This avoids the problem of excessive or insufficient application of welding material that may be caused by directly applying welding material on the pad. Precise control of the amount applied can also reduce the waste of welding materials and reduce production costs. At the same time, it also helps to improve welding efficiency and shorten welding time.

[0112] See also Fig. 9 and Fig.10 , Fig. 9 and Fig.10 The effects of this embodiment are intuitively demonstrated. Fig. 9 This is a diagram showing the effect of coating the welding material without using the solution of this embodiment. Fig.10 This is a diagram showing the effect of welding material coating after using the corresponding solution proposed in this embodiment. It can be seen from this that Fig. 9 The welding material enters the opening and the opening is completely blocked; Fig.10 The middle opening is clear, ensuring that welding materials do not enter the opening.

[0113] In summary, in this embodiment, during the coating of the welding material, the opening area on the pad is shielded to ensure that the welding material is only coated on the designated welding area, effectively preventing the welding material from entering the opening area. At the same time, the protective area coating outside the opening area can further prevent the welding material from entering the opening area, so that the opening on the pad is not affected by the welding material, reducing the damage and rework of the circuit board caused by the welding material mistakenly entering the opening area. In addition, the welding material will not enter the opening area, ensuring that the welding material of the pad will not be lost, avoiding the risks of false welding and tombstones, and reducing production and product costs.

[0114] Embodiment 2:

[0115] In Example 1, a welding method for a solder pad with a hole is proposed. In this embodiment, a power module with a solder pad with a hole is proposed. The power module includes: a circuit board and a welding element welded on the circuit board; a solder pad with a hole is provided on the circuit board, and the welding element is welded to the solder pad by using the welding method for the solder pad with a hole.

[0116] For the specific steps of the welding method of the soldering pad with a hole, please refer to Example 1, which will not be repeated in this embodiment.

[0117] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A welding method for a pad with a hole, characterized in that: The pad with openings includes a welding area and an opening area, and the method includes: Coating a protective material on the periphery of the opening area to form a protective area coating; The protective area coating and the opening area are shielded, and the welding material is coated on the welding area; A welding element is placed on the welding area, and the welding element is welded to the welding area through a welding process.

2. The welding method of the soldering pad with a hole according to claim 1, characterized in that: The coating of welding material in the welding area comprises: A welding coating template is provided, and the welding coating template is provided on the welding pad, and the welding material is coated on the welding area through the welding coating template.

3. The welding method of the soldering pad with a hole according to claim 2, characterized in that: The step of setting a welding coating template, setting the welding coating template on the welding pad, and coating the welding material on the welding area through the welding coating template comprises: A welding coating template having a size matching that of the welding pad is provided; wherein the welding coating template is provided with a hollow area matching that of the welding area; The welding coating template is set on the welding pad, and the hollow area is aligned with the welding area, so that the welding area is completely exposed, and the opening area and the protective area coating are completely shielded; the welding material coating of the welding area is completed through the welding coating template.

4. The welding method of the pad with opening according to claim 2, characterized in that: The step of setting a welding coating template, setting the welding coating template on the welding pad, and coating the welding material on the welding area through the welding coating template further comprises: Mounting the solder coating template on a solder coating machine and aligning the solder coating template with the solder pad; Controlling a scraper on the welding coating machine to move on the welding coating template at a preset pressure and a preset angle, and printing the welding material to the welding area on the pad through the hollow area on the welding coating template to complete the coating of the welding material on the pad; Wherein, the preset speed and preset pressure of the scraper are set according to the distance between the welding coating template and the welding pad.

5. The welding method of the pad with opening according to claim 1, characterized in that: The coating of welding material in the welding area further comprises: A welding ejector pin template is provided, and the welding ejector pin template is provided on the welding pad, and the welding area is coated with welding material through the welding ejector pin template.

6. The welding method of the soldering pad with a hole according to claim 5, characterized in that: The step of setting a welding ejector pin template, setting the welding ejector pin template on the welding pad, and applying welding material to the welding area through the welding ejector pin template comprises: A soldering ejector pin template having a size matching that of the soldering pad is provided; wherein the soldering ejector pin template is provided with a shielding ejector pin corresponding to the protective area coating and the opening area, and the shielding ejector pin can move up and down relative to the soldering ejector pin template; Applying welding material on the welding ejector pin template, pushing the shielding ejector pin so that the shielding ejector pin protrudes from the welding ejector pin template, and removing the welding material on the shielding ejector pin; The welding ejector pin template is placed directly above the welding pad, the shielding ejector pin supports the protective area coating and the opening area, the welding ejector pin template is moved downward, and other parts of the welding ejector pin template with welding material are brought into contact with the welding pad to apply the welding material to the welding area.

7. The welding method of the soldering pad with a hole according to claim 1, characterized in that: The coating of welding material in the welding area further comprises: An air blowing device is arranged on the back side corresponding to the opening area; The blowing direction of the blowing device is directed from the non-coated surface on the pad to the coated surface. During the coating process of the welding material, the blowing device is turned on, and gas in the opening area is blown toward the coated surface on the pad to prevent the welding material from entering the opening area.

8. The welding method of the soldering pad with a hole according to claim 1, characterized in that: The coating of welding material in the welding area further comprises: Use a welding printer to print welding material evenly in the welding area; control the amount of welding material applied to form welding spots on the surface of the pad, avoid directly applying welding material on the pad, so as to complete the coating of welding material in the welding area.

9. The welding method of the soldering pad with a hole according to any one of claims 1 to 8, characterized in that: The shape of the protective area coating is circular, square or irregular.

10. A power module with a perforated pad, characterized in that: The power module is obtained according to the welding method with a perforated solder pad according to any one of claims 1 to 9, and the power module comprises: a circuit board and a welding element welded on the circuit board; A soldering pad with an opening is arranged on the circuit board, and the soldering element is soldered on the soldering pad by using the soldering method of the soldering pad with an opening.

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