Circuit board manufacturing method, circuit board, electronic equipment and circuit board production line

Abstract

The invention discloses a circuit board manufacturing method, a circuit board, electronic equipment and a circuit board production line. The circuit board manufacturing method comprises the following steps: mounting a soldering lug in a to-be-mounted chip area of a PCB (Printed Circuit Board); mounting a chip in the to-be-mounted chip area where the soldering lug is mounted; the PCB is arranged in the jig, and the chip is pressed and held; and feeding the jig provided with the PCB into a reflow oven so as to carry out reflow soldering on the PCB. According to the technical scheme provided by the invention, the stability of the chip mounted on the PCB is effectively improved, defective products of insufficient soldering or tin connection of the chip are greatly reduced, and the yield is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit board production, and in particular to a circuit board manufacturing method, a circuit board, an electronic device, and a circuit board production line. Background Art

[0002] At present, various cleaning robot products have a demand for lightness, small size and light weight, which leads to higher and higher integration of chips used in their circuit boards. Under the same volume, the spacing is denser, and the size of chip package (the center distance between two solder joints, also known as pich) has gradually decreased from the initial 1mm to the current 0.4mm or 0.35mm. The smaller the chip, the more difficult it is to weld the chip and the board.

[0003] The welding between the chip and the single board is mainly done by designing a package matching the chip on the PCB, then transferring the solder paste to the corresponding package on the PCB through the steel mesh, and then mounting the BGA on the solder paste through the placement machine, and finally forming a reliable solder joint through the reflow process to achieve electrical connection. However, during the placement and reflow process, the chip will deform or shift, resulting in the solder paste printed on the PCB and the chip solder ball not merging, that is, the cold solder joint or pillow effect, which will lead to the problem of unstable chip mounting on the PCB. Summary of the invention

[0004] The present disclosure provides a circuit board manufacturing method and a circuit board, aiming to solve the problem of unstable connection between a chip and a PCB.

[0005] To achieve the above-mentioned purpose, the present invention provides a method for manufacturing a circuit board, comprising:

[0006] Install solder tabs in the area of ​​the PCB where the chip is to be mounted;

[0007] Mounting a chip in the chip-to-be-mounted area where the solder pad has been mounted;

[0008] Installing the PCB into a jig and pressing the chip;

[0009] Sending the jig with the PCB into a reflow oven to perform reflow soldering on the PCB;

[0010] The chip is provided with solder balls, the solder balls are located on the surface of the chip and the PCB to be soldered, and the solder sheets are staggered with the solder balls.

[0011] In some embodiments, before the step of installing the solder pad in the chip-to-be-mounted area of ​​the PCB, the circuit board manufacturing method includes:

[0012] Determining the support position in the area where the chip is to be installed;

[0013] The step of installing a soldering pad in a chip-to-be-mounted area of ​​a PCB comprises:

[0014] The soldering piece is mounted on the supporting position.

[0015] In some embodiments, the step of determining the support position in the area of ​​the chip to be mounted includes:

[0016] Acquiring dynamic thermal deformation data of the chip, wherein the dynamic thermal deformation data includes deformation size, deformation area, and deformation trend;

[0017] Determining a deformation position of the chip according to at least one of the deformation size, the deformation area, and the deformation trend;

[0018] Setting the support position in a position corresponding to the deformation position in the chip-to-be-installed area, wherein the support position is adjacent to a deformation peak point in the deformation area;

[0019] Wherein, there are one or more support positions.

[0020] In some embodiments, between the step of installing the solder pad in the chip-to-be-mounted area of ​​the PCB and the step of determining the support position in the chip-to-be-mounted area, the method for manufacturing the circuit board includes:

[0021] Acquiring solder ball height and solder ball tolerance data of the solder ball;

[0022] The thickness of the solder piece is determined according to the solder ball height and the solder ball tolerance data, and the shape and size of the solder piece are determined according to the shape and size of the support position.

[0023] In some embodiments, before the step of installing the solder pad in the chip-to-be-mounted area of ​​the PCB, the circuit board manufacturing method includes:

[0024] determining a first deformation region of the chip;

[0025] The step of pressing and holding the chip comprises:

[0026] The jig is used to press and hold the first deformation region of the chip.

[0027] In some embodiments, the step of determining the first deformation region of the chip includes:

[0028] Acquiring dynamic thermal deformation data of the chip, wherein the dynamic thermal deformation data includes deformation size, deformation area, and deformation trend;

[0029] A region adjacent to the deformation peak point in the deformation region is determined as the first deformation region.

[0030] In some embodiments, before the step of installing the solder piece at the support position in the chip-to-be-mounted area of ​​the PCB, the circuit board manufacturing method includes:

[0031] Print tin on the PCB and check whether the printed tin is qualified;

[0032] After confirming that the tin printing is qualified, the step of installing the solder piece in the chip area to be mounted on the PCB is performed;

[0033] After the step of sending the fixture equipped with the PCB into the reflow oven for reflow soldering, the method further includes: optically inspecting the reflowed PCB.

[0034] In some embodiments, the soldering sheet is a stainless steel sheet with a tin or gold plated surface; or, the soldering sheet is made of nickel-white copper or nickel.

[0035] The present disclosure also provides a circuit board, including a PCB and at least one chip mounted on the PCB, at least one welding piece is provided between at least one of the chips and the PCB, and two sides of the welding piece respectively abut against the PCB and the chip.

[0036] In some embodiments, the soldering pad is mounted and fixed on the PCB;

[0037] And / or, the solder pads are separated from the solder balls of the chip.

[0038] The present disclosure also provides an electronic product, including a circuit board manufactured according to the above circuit board manufacturing method, or the above circuit board.

[0039] The present disclosure also provides a circuit board production line, comprising:

[0040] A mounting device is used to install solder pads in the chip area to be mounted on the PCB, and then mount the chip in the chip area to be mounted;

[0041] A board loading device, used for loading the PCB on which the chip is mounted into a jig, and allowing the jig to press and hold the chip;

[0042] A reflow oven is used to perform reflow soldering on the PCB in the fixture.

[0043] The technical solution of the circuit board manufacturing method disclosed in the present invention is to install the soldering sheet in the chip area to be mounted on the PCB first, then mount the chip in the chip area to be mounted, and then load the PCB into the fixture and press the chip to send it into the reflow furnace for reflow. Due to the pressing effect of the fixture on the chip, it is ensured that the chip will not have the problem of cold soldering due to deformation or displacement of the substrate, and due to the supporting effect of the soldering sheet, the problem of bridging caused by excessive pressure is avoided. The circuit board manufacturing method of this embodiment effectively ensures that reliable solder joints can be stably formed between the chip and the PCB, improves the stability of chip mounting on the PCB, greatly reduces the defective products of cold soldering or bridging of the chip, and improves the yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the process of the first embodiment of the method for manufacturing a circuit board disclosed in the present invention;

[0045] Figure 2 It is a schematic diagram of the flow chart of the second embodiment of the method for manufacturing a circuit board disclosed in the present invention;

[0046] Figure 3 It is a schematic diagram of the process of the third embodiment of the method for manufacturing a circuit board disclosed in the present invention;

[0047] Figure 4 It is a schematic flow chart of a fourth embodiment of the method for manufacturing a circuit board disclosed in the present invention;

[0048] Figure 5 It is a schematic flow chart of a fifth embodiment of the method for manufacturing a circuit board disclosed in the present invention;

[0049] Figure 6 It is a flow chart of a sixth embodiment of the method for manufacturing a circuit board disclosed in the present invention;

[0050] Figure 7 It is a flow chart of a seventh embodiment of the method for manufacturing a circuit board disclosed in the present invention;

[0051] Figure 8 It is a schematic structural diagram of an embodiment of a circuit board disclosed in the present invention. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0053] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0054] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0055] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0056] In order to meet the demand for lightweight products, the size of product circuit boards is designed to be smaller and smaller, resulting in higher and higher requirements for chip integration used in circuit boards. The size of chip packages (center distance between two solder joints, also known as pich) has been gradually reduced from the initial 1mm to the current 0.4mm and 0.35mm, and the difficulty of welding chips and PCBs has been greatly increased. The welding between chips and PCBs is mainly done by designing a package that matches the chip on the PCB, then transferring the solder paste to the corresponding package on the PCB through a steel mesh, and then mounting the chip on the solder paste through a placement machine. Finally, a reliable solder joint is formed through a reflow soldering process to achieve electrical connection.

[0057] Since the current limit of the steel mesh opening is 0.17mm, when the chip's pich value reaches 0.35mm, the maximum opening of the steel mesh can only be 0.18mm. For the steel mesh to tin normally, two conditions must be met:

[0058] ①Opening width-to-thickness ratio = opening width / steel sheet thickness>1.5;

[0059] ② Area ratio = opening area / opening hole wall area>0.67;

[0060] When the opening size is entered and the preset opening thickness is 0.1mm, the area ratio = 3.14*0.09*0.09* / 3.14*0.18*0.1 = 0.45, which is much smaller than 0.67; when the thickness is changed to the limit of 0.07mm, the area ratio is 0.64, which barely meets the requirements.

[0061] However, the chip itself has a flatness tolerance of the solder balls and a thermal deformation tolerance of the substrate. When the tolerances accumulate and exceed the thickness of the solder paste, the solder paste printed on the PCB and the chip solder balls will not fuse together, which is also commonly known as cold solder joints or the pillow effect, causing the chip to be unstable when mounted on the PCB.

[0062] Based on the above problems, the present disclosure proposes a circuit board manufacturing method, which can effectively control the deformation of the substrate during the reflow process, thereby solving the problem of unstable connection between the chip and the PCB caused by chip deformation or displacement during the mounting and reflow process.

[0063] Public as Figure 1 As shown, Figure 1 It is a flow chart of the first embodiment of the circuit board manufacturing method disclosed in the present invention.

[0064] In this embodiment, the circuit board manufacturing method includes:

[0065] Step S10, installing a soldering pad in the chip-to-be-mounted area of ​​the PCB;

[0066] There are one or more chip-to-be-mounted areas on the PCB, and each chip-to-be-mounted area is used to mount the corresponding chip. There are many solder joints distributed in each chip-to-be-mounted area, and there are empty spaces between the solder joints. Before mounting the chip, a soldering lug is first installed in the chip-to-be-mounted area. The soldering lug is installed at the empty space in the chip-to-be-mounted area, and the soldering lug is spaced apart from the solder joints in the chip-to-be-mounted area, so as not to interfere with the solder joints, that is, the soldering lug will not affect the normal operation of the chip. Among them, the number of soldering lugs installed in the chip-to-be-mounted area can be one or more, which can be determined according to specific needs; the shape of the soldering lug can be oval, square, circular, polygonal, ring, strip, and the like. The soldering lug can be installed by mounting, or other feasible installation methods can be used. In this embodiment, the soldering lug is used to support the chip mounted in the chip-to-be-mounted area so as to maintain a distance between the chip and the PCB.

[0067] In some embodiments, the soldering pad can be a stainless steel pad with a tin or gold plated surface. The soldering pad is made of stainless steel material to ensure that the soldering pad is not easy to corrode, and to avoid the interference of the soldering pad corrosion on the soldering point, thereby affecting the normal operation of the chip. At the same time, the soldering pad is tinned or gold plated to ensure the solderability of the soldering pad, so that the soldering pad can be easily installed in the chip area to be installed by mounting. In some embodiments, the soldering pad can also be made of nickel white copper or nickel, so that the soldering pad is not only corrosion-resistant, but also can meet the needs of soldering pad grounding.

[0068] In addition, the PCB in step S10 can be a PCB that has completed the tin printing process, or a PCB that has not yet undergone the tin printing process; that is, the tin printing process can be performed before step S10, or after step S10 and before step S20.

[0069] Step S20, mounting a chip in the chip-to-be-mounted area where the solder pad has been mounted;

[0070] After the solder pads are installed in the chip area to be mounted on the PCB, the chip is mounted to the chip area to be mounted. If there are multiple chips, each chip is mounted to its corresponding chip area to be mounted. The chip is provided with solder balls, which are located on the surface of the chip to be soldered to the PCB, that is, the solder balls are located on the side of the chip facing the chip area to be mounted. The solder pads in the chip area to be mounted and the solder balls of the chip are staggered to prevent the solder pads from connecting the solder balls of the chip and causing chip failure.

[0071] Step S30, loading the PCB into the fixture and pressing the chip;

[0072] After the chip is mounted on the PCB, the PCB with the chip mounted is loaded into a jig, wherein the jig is provided with a pressing part, and the chip mounted on the PCB is pressed by the pressing part of the jig. The pressing part of the jig can be set to adjust the pressing force, so that different sizes of pressing forces can be used for pressing different chips. The jig can be provided with multiple pressing parts, and different pressing parts can be used to press different positions of the same chip, or different pressing parts can be used to press different chips; the jig can also use only one pressing part to press all the chips on the PCB.

[0073] Step S40, sending the fixture with the PCB into a reflow oven to perform reflow soldering on the PCB.

[0074] After the jig is installed with the PCB, the jig with the PCB is sent to the reflow oven, and the PCB is reflowed through the reflow oven to allow the chip to be soldered and fixed to the PCB. Under the high temperature in the reflow oven, the chip substrate usually undergoes a certain deformation. However, since the chip is held by the pressing part of the jig, the chip is prevented from deforming and arching. Under the pressing action, the chip is pressed close to the PCB board, so that the solder balls between the chip and the PCB that have not been in contact and fused are brought close to fuse, thereby forming a reliable solder joint. At the same time, because the solder sheet supports the chip, it limits the chip from getting too close to the PCB board, thereby effectively avoiding the problem of bridging caused by the chip getting too close to the PCB board under the pressing action. The spacing between the chip and the PCB of the circuit board obtained by reflow soldering will be smaller than the sum of the solder ball height on the chip and the solder height on the PCB before soldering, and will usually be larger than half of the sum of the solder ball height and the solder height (of course, in some embodiments, it can be smaller, such as larger than one-fifth to two-fifths of the sum of the solder ball height and the solder height), for example, the spacing is four-fifths of the sum of the solder ball height and the solder height.

[0075] The technical solution of the circuit board manufacturing method of this embodiment is to first install the soldering piece in the chip area to be mounted on the PCB, then mount the chip in the chip area to be mounted, and then load the PCB into the fixture and press the chip to send it into the reflow furnace for reflow. Due to the pressing effect of the fixture on the chip, it is ensured that the chip will not have the problem of cold soldering due to deformation or displacement of the substrate, and due to the supporting effect of the soldering piece, the problem of bridging caused by the chip being pressed too heavily by the fixture is effectively avoided. The circuit board manufacturing method of this embodiment effectively ensures that reliable solder joints can be stably formed between the chip and the PCB, improves the stability of chip mounting on the PCB, greatly reduces the defective products of cold soldering or bridging of the chip, and improves the yield rate.

[0076] like Figure 2 As shown, Figure 2 It is a flow chart of the second embodiment of the circuit board manufacturing method disclosed in the present invention.

[0077] In this embodiment, before step S10, the circuit board manufacturing method includes:

[0078] Step S50, determining the support position in the area where the chip is to be installed;

[0079] Due to the complex distribution of solder joints in the chip-to-be-mounted area, the sizes of vacancies at different positions in the chip-to-be-mounted area are usually different. Some vacancies are too small to be used to install solder lugs or may interfere with surrounding solder joints after installing solder lugs. In addition, the position of the chip held by the fixture is different, and the installation position of the solder lug also needs to be adjusted accordingly to provide better support for the chip. Therefore, before installing solder lugs in the chip-to-be-mounted area, it is necessary to first analyze and determine the support positions in the chip-to-be-mounted area (the position, shape, and size in the chip-to-be-mounted area), that is, determine the position area that can be used to install the solder lug and the shape and size of the position area. Among them, the number of support positions in each chip-to-be-mounted area is one or more.

[0080] Step S10 includes: Step S11, installing a welding piece at a supporting position.

[0081] After the position information of the support position is determined, a welding piece of a suitable shape and size is installed on the support position according to the position, shape and size information of the support position.

[0082] The technical solution of the circuit board manufacturing method of the present embodiment first determines the position area, shape and size of the support position for installing the soldering lug in each chip area to be installed through analysis, that is, determines the support position area in each chip area to be installed that has a better support effect for each corresponding chip, and the shape and size of the support position area, and then installs the soldering lug of appropriate shape and size on the support position according to the information of the determined support position; in this way, by reasonably installing and setting the soldering lug, a better support effect can be achieved by using fewer soldering lugs, avoiding the problem of blind installation of the soldering lugs.

[0083] like Figure 3 As shown, Figure 3 It is a flow chart of the third embodiment of the circuit board manufacturing method disclosed in the present invention.

[0084] This embodiment is based on the technical solution of the second embodiment. In this embodiment, step S50 of the circuit board manufacturing method includes:

[0085] Step S51, obtaining dynamic thermal deformation data of the chip.

[0086] In this embodiment, the dynamic thermal deformation data of the chip can be obtained by thermal simulation test of the chip model, and the dynamic thermal deformation data includes deformation size, deformation area and deformation trend. The dynamic thermal deformation data of various chips can also be tested and saved in advance. When the dynamic thermal deformation data of a chip is needed, the dynamic thermal deformation data of the chip can be directly queried from the database. According to the dynamic thermal deformation data, the deformation size, deformation area and deformation trend of the chip in the reflow furnace can be known.

[0087] Step S52, determining the deformation position of the chip according to at least one of the deformation size, deformation area and deformation trend;

[0088] After the dynamic thermal deformation data of the chip is obtained, the deformation site of the chip is further determined according to the deformation size and / or deformation area and / or deformation trend in the dynamic thermal deformation data; for example, a special position point in each deformation area (such as a point with the largest deformation size, i.e., a deformation peak point) may be determined as a deformation site, or a point in the deformation area where the deformation size reaches a preset value may be determined as a deformation site, or an area where the deformation size exceeds a preset value may be determined according to the direction of the deformation trend, and a preset number of points in the area may be selected as deformation sites, and the like.

[0089] Step S53, setting a support position in a position corresponding to the deformation point in the area to be mounted with the chip, wherein the support position is adjacent to the deformation peak point in the deformation area.

[0090] During the reflow soldering process of the chip in the reflow oven, the pressing force of the fixture on the deformation area of ​​the chip will be relatively large. The deformation area is most likely to cause bridging due to excessive pressure from the fixture. Therefore, the deformation area of ​​the chip needs to be supported by a solder piece. Therefore, in this embodiment, a support position (one or more) is set in the position corresponding to the deformation site of the deformation area in the area to be installed of the chip to install the solder piece; and the deformation sizes at different positions in the deformation area are different, and there is a position point with the largest deformation (that is, the deformation peak point). The deformation peak point of the chip receives the largest pressing force from the fixture. Therefore, the support position is set at the position of the deformation peak point in the adjacent deformation area to support the area adjacent to the deformation peak point.

[0091] The circuit board manufacturing method of the present embodiment obtains the dynamic thermal deformation data of the chip to determine the deformation sites in the deformation area of ​​the chip during the reflow soldering process in the reflow furnace according to the dynamic thermal deformation data, and then determines the support position setting positions in the area where the chip is to be installed (i.e., the positions corresponding to the deformation sites in the deformation area) according to the deformation sites of the chip. The positions of the respective support positions are adjacent to the deformation peak points of the corresponding deformation areas, respectively, so that the support positions can specifically support the area of ​​the chip with the greatest pressure, thereby ensuring that the chip will not be pressed too hard by the fixture to cause the problem of bridging.

[0092] like Figure 4 As shown, Figure 4 4 is a flow chart of a fourth embodiment of the circuit board manufacturing method disclosed in the present invention.

[0093] This embodiment is based on the technical solution of the second embodiment or the third embodiment. In this embodiment, between step S10 and step S50, the circuit board manufacturing method includes:

[0094] Step S60, obtaining solder ball height and solder ball tolerance data of the solder ball;

[0095] In this embodiment, the solder ball height and solder ball tolerance data of the solder balls between the chip and the PCB can be determined according to the solder ball parameters of the chip or the steel mesh specifications used in the tin printing process. The solder ball height and tolerance data of various chips can be saved in a database. When the solder ball height and tolerance data of the chip are needed, they can be directly queried from the database according to the chip model.

[0096] Step S70, determining the thickness of the solder pad according to the solder ball height and the solder ball tolerance data, and determining the shape and size of the solder pad according to the shape and size of the support position.

[0097] After obtaining the solder ball height and solder ball tolerance data of the chip, the thickness of the solder piece is determined based on these data, so that the thickness of the solder piece satisfies the following relationship: greater than the spacing between the chip and the PCB when the adjacent solder balls of the chip are tinned together, and less than the spacing between the chip and the PCB when the solder balls of the chip are not fused (and the solder joints between the chip and the PCB are disconnected and not in contact). In addition, according to the shape and size of the support position determined in step S50, the shape and size of the solder piece are determined accordingly. The requirements for the shape and size of the solder piece need to ensure that after the solder piece is installed in the support position, the interval between the solder piece and the surrounding solder joints exceeds the preset safety distance. For example, the shape and size of the solder piece can be determined by scaling the shape and size of the support position to a preset percentage (such as 80%, 70%, 60%, etc.) to obtain the shape and size of the solder piece; or, the shape and size of the solder piece can also be determined by selecting a solder piece whose shape is similar to the shape of the support position from several solder pieces of preset shapes, and whose edge is preset to exceed the safety distance from the edge of the support position.

[0098] The circuit board manufacturing method of the present embodiment determines the thickness of the solder piece through the solder ball height and solder ball tolerance data of the solder ball, and determines the shape and size of the solder piece according to the shape and size of the support position, so that after the solder piece is installed in the support position, a safe distance is maintained between the solder piece and the solder joint of the chip to avoid interference with the solder joint. At the same time, it is ensured that the spacing between the chip and the PCB will not be too large or too small during the reflow soldering of the chip in the reflow oven, thereby avoiding the occurrence of unfused solder balls or solder balls being tinned together, so that reliable solder joints are formed between the chip and the PCB, thereby ensuring a stable connection between the chip and the PCB.

[0099] In some embodiments, the thickness of the solder sheet can also be determined by slicing the finished circuit board or sample with the chip soldered to measure the average height of the solder ball after collapse, and determining the thickness of the solder sheet to be the same as the average height of the solder ball after collapse; typically the average height of the solder ball after collapse is about 50% of the initial height of the solder ball.

[0100] like Figure 5 As shown, Figure 5 It is a flow chart of the fifth embodiment of the circuit board manufacturing method disclosed in the present invention.

[0101] This embodiment may be based on the technical solution of any of the above embodiments. In this embodiment, before step S10, the circuit board manufacturing method includes:

[0102] Step S80, determining a first deformation region of the chip;

[0103] The first deformation region can be determined according to the thermal simulation results of the chip model. The first deformation region can be a region with the largest deformation size (i.e., deformation amount) (such as a region near the deformation peak point, or a region including the deformation peak point), or a region with a deformation size exceeding a preset amount, etc. The number of first deformation regions can be one or more; for example, multiple regions are selected around the deformation peak point as the first deformation region, and the chip includes multiple dispersed regions with deformation sizes exceeding a preset amount (such as the four corner regions of the chip), and each region is determined as the first deformation region.

[0104] In step S30, the step of pressing and holding the chip includes: step S31, pressing and holding the first deformation area of ​​the chip by using a fixture.

[0105] After knowing the position of the first deformation area of ​​the chip, when the PCB with the chip mounted is loaded into the jig, the pressing part of the jig is used to press the first deformation area of ​​the chip. If the chip has multiple first deformation areas, multiple pressing parts can be used to press each first deformation area separately. In addition, the solder sheet will also be installed in the area corresponding to the chip area to be mounted and the first deformation area according to the position of the first deformation area, so as to support the first deformation area pressed by the jig.

[0106] The circuit board manufacturing method of the present embodiment predetermines the first deformation area of ​​the chip. When the PCB with the mounted chip is loaded into the jig, the jig is pressed against the first deformation area of ​​the chip, thereby effectively limiting the deformation of the chip during the reflow soldering process, avoiding the situation where the solder balls of the chip are disconnected and not in contact, and the solder balls are connected, so that reliable solder joints are formed between the chip and the PCB.

[0107] like Figure 6 As shown, Figure 6 It is a flow chart of the sixth embodiment of the circuit board manufacturing method disclosed in the present invention.

[0108] This embodiment may be based on the technical solution of the fifth embodiment. In this embodiment, step S80 includes:

[0109] Step S81, obtaining dynamic thermal deformation data of the chip;

[0110] The dynamic thermal deformation data of the chip can be obtained through thermal simulation testing of the chip model, and the dynamic thermal deformation data includes deformation size, deformation area and deformation trend. The dynamic thermal deformation data of various chips can also be tested and saved in advance. When the dynamic thermal deformation data of a chip is needed, the dynamic thermal deformation data of the chip can be directly queried from the database.

[0111] Step S82: determine the area in the deformation area adjacent to the deformation peak point as the first deformation area.

[0112] According to the deformation size, deformation area and deformation area of ​​the chip, the deformation peak point in the deformation area can be determined, and at least one area adjacent to the deformation peak point is selected from the deformation area as the first deformation area, and the first deformation area is the area with a larger deformation size. Among them, the first deformation area can be an annular area surrounding the deformation peak point. When the chip has multiple scattered deformation areas (for example, the four corner areas of the chip are all deformation areas), each deformation area has a deformation peak point. At this time, the area adjacent to the deformation peak point in each deformation area can be determined as the first deformation area.

[0113] The circuit board manufacturing method of this embodiment determines the deformation peak point in the deformation area according to the dynamic thermal deformation data of the chip, and determines the area adjacent to the deformation peak point as the first deformation area, that is, determines the area with the largest deformation size in the deformation area, so that the treatment can effectively press and hold the area of ​​the chip with the largest deformation, better limit the deformation of the chip during the reflow soldering process, and better avoid the situation where the solder balls of the chip are disconnected and not in contact and the solder balls are tinned together.

[0114] like Figure 7 As shown, Figure 7 It is a flow chart of the seventh embodiment of the circuit board manufacturing method disclosed in the present invention.

[0115] In this embodiment, before step S10, the circuit board manufacturing method includes:

[0116] Step S90, printing tin on the PCB and checking whether the printed tin is qualified;

[0117] After confirming that the tin printing is qualified, step S10 is executed;

[0118] In this embodiment, before installing the soldering pad in the area of ​​the chip to be installed, tin is first printed on the PCB to form solder on each solder joint in the area of ​​the chip to be installed. After the tin printing operation, the PCB is inspected (tin printing detection equipment can be used for inspection) to confirm whether the solder formed on each solder joint in the area of ​​the chip to be installed is qualified. After confirming that the tin printing is qualified, continue to execute step S10 to install the soldering pad. If the tin printing of the PCB is unqualified, the current PCB can be subjected to the tin printing process again, or the current PCB can be sent to a defective product recycling site, etc. In this embodiment, by first printing the tin on the PCB before installing the soldering pad, the problem of increased difficulty in tin printing due to interference from the soldering pad can be avoided, thereby better ensuring the qualified rate of tin printing.

[0119] After step S40, the circuit board manufacturing method further includes: step S100, optically inspecting the reflowed PCB.

[0120] After the PCB has completed reflow soldering in the reflow oven, an optical inspection is performed on the PCB sent out of the reflow oven (it can be automatically inspected using a high-precision optical impact detection system) to confirm whether the reflow soldering process of the PCB is qualified, thereby filtering out qualified products and defective products respectively.

[0121] It should be noted that, in the case where there are no contradictions or conflicts between the solutions of all the above embodiments of the present application, the above embodiments can be arbitrarily combined or combined to form new embodiments.

[0122] The present disclosure also provides a circuit board.

[0123] Reference Figure 8 The circuit board of this embodiment includes a PCB10 and at least one chip 30 mounted on the PCB10. At least one soldering piece 20 is provided between the at least one chip 30 and the PCB10. The two sides of the soldering piece 20 abut against the PCB10 and the chip 30 respectively. In the manufacturing process of the circuit board of this embodiment, during the reflow soldering of the PCB10 and the chip 30, the chip 30 can be pressed by a fixture to prevent the chip 30 from warping and deforming, causing the solder balls 31 between the chip 30 and the PCB10 to be disconnected and not in contact (that is, the solder balls 31 are not fused), and the chip 30 is supported by the soldering piece 20 to prevent the chip 30 from collapsing under the pressure of the fixture, causing the solder balls 31 to be tinned; therefore, the circuit board of this embodiment enables reliable solder joints to be formed between the chip 30 and the PCB10, improves the qualified rate of the reflow soldering of the PCB10, and further improves the good rate of the circuit board.

[0124] In some embodiments, the soldering pad 20 may be a stainless steel sheet with a tin or gold plated surface. The soldering pad 20 is made of stainless steel material to ensure that the soldering pad 20 is not easy to corrode, and to avoid the corrosion of the soldering pad 20 interfering with the solder joints, thereby affecting the normal operation of the chip 30. At the same time, the soldering pad 20 is soldered by tin plating or gold plating to ensure the solderability of the soldering pad 20, so that the soldering pad 20 is conveniently installed in the area of ​​the chip 30 to be installed by mounting. In some embodiments, the soldering pad 20 may also be made of nickel white copper or nickel, so that the soldering pad 20 is not only corrosion-resistant, but also can meet the requirements of grounding the soldering pad 20. In some embodiments, the soldering pad 20 is separated from the solder ball 31 of the chip 30, so that the soldering pad 20 does not interfere with the solder ball 31, thereby not affecting the performance and normal operation of the chip 30.

[0125] In some embodiments, the soldering piece 20 is mounted on the PCB 10 by mounting, so that the mounting of the soldering piece 20 and the mounting of the chip 30 can share a mounting device, reducing the equipment cost. Of course, in other embodiments, the soldering piece 20 can also be mounted on the PCB 10 by other methods.

[0126] The present disclosure also proposes an electronic device, including a circuit board manufactured according to the above circuit board manufacturing method, or the above circuit board. The manufacturing method and specific structure of the circuit board can refer to the above embodiments. Since the electronic product adopts all the technical solutions of all the above circuit board embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here one by one.

[0127] The present disclosure also provides a circuit board production line, comprising:

[0128] Placement equipment, used to install solder pads in the chip-to-be-mounted area of ​​the PCB, and then place chips in the chip-to-be-mounted area;

[0129] The board loading equipment is used to load the PCB with mounted chips into the fixture and make the fixture press the chip;

[0130] Reflow oven, used to reflow soldering the PCB in the fixture.

[0131] The production process of the circuit board production line of this embodiment can be as follows: the PCB board with qualified tin printing is transported to the mounting equipment, the mounting equipment first installs the solder pad (mounting solder pad) in the chip area to be mounted on the PCB, and then mounts the chip in the chip area to be mounted, and the PCB with the chip mounted is transported to the board mounting equipment, the board mounting equipment puts the PCB with the chip mounted into the fixture, and allows the fixture to press the chip; the fixture with the PCB is sent to the reflow oven, and the reflow oven reflows the PCB in the fixture; the reflow oven transports the equipment that has completed the reflow, and the optical inspection equipment can be used to check whether the reflow of the PCB is qualified, and the finished circuit board is obtained if the reflow is qualified.

[0132] Since the circuit board production line of this embodiment can execute the circuit board manufacturing method in the above embodiment and can also manufacture the circuit boards in the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0133] The above description is only a partial or preferred embodiment of the present disclosure. Neither the text nor the drawings can limit the scope of protection of the present disclosure. All equivalent structural transformations made using the contents of the present disclosure and the drawings under the overall concept of the present disclosure, or direct / indirect application in other related technical fields are included in the scope of protection of the present disclosure.

Claims

1. A method for manufacturing a circuit board, characterized in that: include: Install solder tabs in the area of ​​the PCB where the chip is to be mounted; Mounting a chip on the chip-to-be-mounted area where the solder pad has been mounted; Installing the PCB into a jig and pressing the chip; Sending the jig with the PCB into a reflow oven to perform reflow soldering on the PCB; The chip is provided with solder balls, the solder balls are located on the surface of the chip and the PCB to be soldered, and the solder sheets are staggered with the solder balls.

2. The method for manufacturing a circuit board according to claim 1, characterized in that: Before the step of installing the soldering piece in the chip-to-be-mounted area of ​​the PCB, the method for manufacturing the circuit board includes: Determining the support position in the area where the chip is to be installed; The step of installing a soldering pad in a chip-to-be-mounted area of ​​a PCB comprises: The welding piece is installed at the supporting position.

3. The method for manufacturing a circuit board according to claim 2, characterized in that: The step of determining the support position in the area of ​​the chip to be mounted includes: Acquiring dynamic thermal deformation data of the chip, wherein the dynamic thermal deformation data includes deformation size, deformation area, and deformation trend; determining a deformation position of the chip according to at least one of the deformation size, the deformation area and the deformation trend; Setting the support position in a position corresponding to the deformation position in the chip-to-be-installed area, wherein the support position is adjacent to a deformation peak point in the deformation area; Wherein, there are one or more support positions.

4. The method for manufacturing a circuit board according to claim 2, characterized in that: Between the step of installing the soldering piece in the chip-to-be-mounted area of ​​the PCB and the step of determining the support position in the chip-to-be-mounted area, the method for manufacturing the circuit board includes: Acquiring solder ball height and solder ball tolerance data of the solder ball; The thickness of the solder piece is determined according to the solder ball height and the solder ball tolerance data, and the shape and size of the solder piece are determined according to the shape and size of the support position.

5. The method for manufacturing a circuit board according to claim 1, characterized in that: Before the step of installing the soldering pad in the chip-to-be-mounted area of ​​the PCB, the circuit board manufacturing method includes: determining a first deformation region of the chip; The step of pressing and holding the chip comprises: The jig is used to press and hold the first deformation region of the chip.

6. The method for manufacturing a circuit board according to claim 5, characterized in that: The step of determining the first deformation area of ​​the chip comprises: Acquiring dynamic thermal deformation data of the chip, wherein the dynamic thermal deformation data includes deformation size, deformation area, and deformation trend; A region adjacent to the deformation peak point in the deformation region is determined as the first deformation region.

7. The method for manufacturing a circuit board according to claim 1, characterized in that: Before the step of installing the solder piece at the support position in the chip-to-be-mounted area of ​​the PCB, the circuit board manufacturing method includes: Print tin on the PCB and check whether the printed tin is qualified; After confirming that the tin printing is qualified, the step of installing the solder piece in the chip area to be mounted on the PCB is performed; After the step of sending the fixture equipped with the PCB into the reflow oven for reflow soldering, the method further includes: optically inspecting the reflowed PCB.

8. The method for manufacturing a circuit board according to claim 1, characterized in that: The soldering sheet is a stainless steel sheet with a tin or gold plated surface; or, the soldering sheet is made of nickel-white copper or nickel.

9. A circuit board, comprising a PCB and at least one chip mounted on the PCB, characterized in that: At least one soldering piece is disposed between at least one of the chips and the PCB, and two sides of the soldering piece abut against the PCB and the chip respectively.

10. The circuit board according to claim 9, characterized in that: The soldering sheet is mounted and fixed on the PCB; And / or, the solder pads are separated from the solder balls of the chip.

11. An electronic device, characterized in that: It comprises a circuit board manufactured according to the circuit board manufacturing method according to any one of claims 1 to 8, or a circuit board according to claim 9 or 10.

12. A circuit board production line, characterized in that: include: A mounting device is used to mount solder pads in the chip-to-be-mounted area of ​​the PCB, and then mount the chip in the chip-to-be-mounted area; A board loading device, used for loading the PCB on which the chip is mounted into a jig, and allowing the jig to press and hold the chip; A reflow oven is used to perform reflow soldering on the PCB in the fixture.

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