Tool for assisting gold removal of chip with pins and gold removing and tin coating method
阅读说明：本技术 一种辅助带引脚贴装芯片除金的工装及除金搪锡方法 (Tool for assisting gold removal of chip with pins and gold removing and tin coating method ) 是由 赵璐 徐子强 王大伟 李杰林 张凯歌 于 2020-06-19 设计创作，主要内容包括：本发明公开了一种辅助带引脚贴装芯片除金的工装,包含芯片载板(1)、压条(2)、硅胶垫块(3)和不脱卸紧固螺钉(4),芯片载板(1)为正方形,芯片载板(1)的一个面上排列有若干个用于摆放芯片方形凸台(11)和圆柱凸台(13)；压条(2)的二端上设有螺纹孔,压条(2)的宽度不超过方形凸台(11)的宽度；不脱卸紧固螺钉(4)拧入螺纹孔和圆柱凸台(13)进行固定；硅胶垫块(3)粘贴在压条(2)对应方形凸台(11)中心的位置。本发明可以提高芯片去金搪锡效率和焊接质量。(The invention discloses a tool for assisting gold removal of a chip with a lead mounting structure, which comprises a chip carrier plate (1), a pressing strip (2), a silica gel cushion block (3) and a non-detachable fastening screw (4), wherein the chip carrier plate (1) is square, and a plurality of square bosses (11) and cylindrical bosses (13) for placing chips are arranged on one surface of the chip carrier plate (1); threaded holes are formed in two ends of the pressing strip (2), and the width of the pressing strip (2) is not more than that of the square boss (11); the fastening screw (4) without being detached is screwed into the threaded hole and the cylindrical boss (13) for fixing; the silica gel cushion block (3) is adhered to the position of the pressing strip (2) corresponding to the center of the square boss (11). The invention can improve the gold-removing tin-coating efficiency and the welding quality of the chip.)
1. The utility model provides an auxiliary tape lead pastes dress chip and removes golden frock, contains chip support plate (1), layering (2), silica gel cushion (3) and does not detach fastening screw (4), its characterized in that:
the chip carrier plate (1) is square, and a plurality of square bosses (11) and cylindrical bosses (13) are arranged on one surface of the chip carrier plate (1); the square bosses (11) are arranged in the central area of the chip carrier plate (1) in a matrix manner of N x N, and the distances between the adjacent square bosses (11) are the same; a groove (12) matched with the size of the chip to be subjected to gold removal is arranged on the square boss; the cylindrical bosses (13) are arranged on four edges of the chip carrier plate (1), N cylindrical bosses (13) are arranged on each edge, the cylindrical bosses and the square bosses (11) in the same row are in the same straight line, and the cylindrical bosses (13) are provided with threaded holes for screwing the fastening screws (4) which are not detached;
two ends of the pressing strip (2) are also provided with threaded holes for screwing the fastening screws (4) without detaching, and the width of the pressing strip (2) is not more than that of the square boss (11);
the silica gel cushion block (3) is adhered to the position of the pressing strip (2) corresponding to the center of the square boss (11).
2. The tooling for assisting in removing gold from a tape-leaded chip according to claim 1, characterized in that the chip carrier board (1) is made of a carbon fiber board.
3. The tooling for assisting in removing gold from a tape pin mounted chip according to claim 1, wherein the material of the pressing strip (2) is a carbon fiber plate.
4. A gold-removing tin-coating method is realized by using the auxiliary gold-removing tool for the chip with the pins as claimed in any one of claims 1 to 3, and comprises the following steps:
firstly, a chip with pins is placed in a groove (12) on a chip carrier plate (1), and a pressing strip (2) and the chip carrier plate (1) are fastened through a non-detachable screw; wherein; the pin placing directions of all the chips are consistent;
and step two, fixing the chip carrier plate (1) with the chip surface on a selective wave-soldering universal carrier after the chip carrier plate faces downwards, selecting a gold removing program corresponding to the chip through a control panel of the selective wave-soldering machine, automatically starting a chip gold removing process, and sequentially completing the processes of feeding, scaling powder spraying, preheating, gold removing, tin coating and blanking of the chip.
5. The method for removing gold and tin coating according to claim 4, further comprising the following steps:
and step four, rotating the pressing strip (2) by 90 degrees for fastening, and repeating the step three.
Technical Field
The invention belongs to the related field of Surface Mount Technology (SMT), and particularly relates to an automatic gold removing tool and method for a chip with a pin to be mounted, in particular to a tool and method for automatically removing gold plating layers of pins of a chip to be mounted, such as QFP, QFN and SOP, with pins on two sides or four sides.
Background
According to the regulations in domestic and foreign relevant standards such as GJB/Z163, IPC/EIA J-STD-001G, QJ3117-99 and the like, gold removal is carried out on a pin gold-plated device before surface assembly welding so as to avoid the problem that a gold-containing welding point is cracked due to gold brittleness in the using process, the mechanical property of the welding point is reduced, and the reliability of electrical connection is seriously influenced. For aerospace products, the environmental requirements are strict and the reliability requirements are high, and the phenomenon of 'gold brittleness' seriously affects the reliability and service life of the products during service, and corresponding gold removing operation is required.
In recent years, with the further improvement of the autonomous controllable requirements of the weapon equipment in our country, the localization proportion of various types of electronic components is higher and higher, and even some types of electronic components have provided 100% localization requirements. Under the background, more and more chips with gold-plated pins are used in national weaponry, the chips are mostly ceramic packaged chips produced by domestic manufacturers, the surfaces of the pins are plated with 100% of gold, the thickness of a gold layer is 1.3-5.7 micrometers, the minimum pin pitch of the chips is 0.5mm, and the minimum pin length is about 1 mm.
QFP, QFN, SOP and other chips with pins on two sides or four sides are square flat surface-mounted chips, the chip package size is small, the number of pins is large and small, the pin pitch can be as small as 0.5mm, and the usage amount of the chip in practical use is large. At present, the gold removing method in the industry is mostly to use a tin pot to manually remove gold with the assistance of a tool, and the method mainly has the following problems:
1. the manual operation is easy to cause the deformation of the pins, the welding difficulty and the cold joint risk are increased, the manual operation efficiency is low, the consistency is poor, and the method is not suitable for large-batch gold and tin removing operation;
2. the chip pins are fine and small in length, and the manual gold and tin removing and coating easily generates welding defects such as bridging and the like;
3. for the mounting chips with pins on two sides or four sides, such as QFP, QFN, SOP and the like, the pitch of which is less than or equal to 0.65mm and the pin length of which is less than or equal to 1mm, the defect of continuous tin of the pins is easy to appear if the manual tin coating is carried out, and the requirement on the skill of manual operation is high.
Disclosure of Invention
Therefore, in order to solve the difficult problem of gold removal of the mounting chips with pins on two sides or four sides, such as QFP, QFN and SOP, avoid the problems of high difficulty and high risk of manual gold removal and improve the gold removal efficiency, the invention aims to provide a tool for assisting in gold removal of the mounting chips with pins and a gold and tin removing method using the tool, so that automatic gold and tin removing operation of the mounting chips with pins on two sides or four sides, such as QFP, QFN and SOP, is realized, and the gold and tin removing efficiency and the welding quality of the chips are improved.
The first purpose of the invention is realized by the following technical scheme:
a tool for assisting gold removal of a chip with pins in mounting comprises a
the
two ends of the
the silica
Preferably, the material of the
Preferably, the material is a carbon fibre sheet.
The other purpose of the invention is realized by the following technical scheme:
a gold removing and tin coating method is realized by utilizing the auxiliary gold removing tool for the chip with the pins, and comprises the following steps:
firstly, a chip with pins is placed in a groove 12 on a
and step two, fixing the
The chip with pins on four sides further comprises the following steps:
and step four, rotating the
The invention has the beneficial effects that:
the tool for assisting the gold removal of the chip with the pins and the gold and tin removing method using the tool have the advantages of simplicity in operation, wide applicability, low cost and the like, and have important significance in improving the gold removal efficiency and the welding quality of the surface-mounted chips with pins on two sides or four sides, such as QFP, QFN, SOP and the like. The invention can improve the efficiency and consistency of gold removing and tin coating operation, reduce the risk of pin deformation in the gold removing process of the surface-mounted chips with pins on two sides or four sides, such as QFP, QFN, SOP and the like, can also carry out automatic gold removing and tin coating on the surface-mounted chips with pins on two sides or four sides, such as QFP, QFN, SOP and the like, with the pitch of less than or equal to 0.65mm and the pin length of less than or equal to 1mm, has wide applicability and low cost, and has important significance for improving the production efficiency and the chip welding quality.
Drawings
Fig. 1 is a schematic structural view of a tool for assisting gold removal of a leaded chip shown in an embodiment.
Fig. 2 is a schematic view of the combination of the pressing bar, the silica gel cushion block and the fastening screw which is not detached.
Fig. 3 is a schematic view of fixing the
Fig. 4 is a schematic structural diagram of a chip carrier.
FIG. 5 is a schematic view of the gold removing direction.
FIG. 6 shows a gold removing process for a two-sided lead mounting chip.
FIG. 7 is a two-sided lead mount chip gold removal process.
Fig. 8 is a two-sided pin mount chip depolluting path.
FIG. 9 is a quad pin mount chip depau path.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Referring to fig. 1 to 4, the tooling for removing gold from a chip with auxiliary leads in this embodiment includes a
The material of the
The material of the
Referring to fig. 2 and 3, the silica
The gold and tin removing method of the gold removing tool for removing gold by using the auxiliary pin-mounted chip comprises the following steps of:
firstly, chips with pins on two sides or four sides, such as QFP, QFN, SOP and the like, are placed in the grooves 12 on the square bosses of the chip carrier plate 1 (when the chips with pins on two sides are placed, the pins of all the chips are placed in the same direction), and the
And step two, turning the chip carrier plate 1 (the side with the chip fixed is downward), fixing the chip carrier plate on a selective wave-soldering universal carrier, selecting a gold removing program corresponding to the chip through a control panel of the selective wave-soldering machine, automatically starting a gold removing process of the chip, and sequentially finishing the processes of feeding, scaling powder spraying, preheating, gold removing, tin coating and blanking of the chip. In the gold removing process, the selective crest welder nozzle moves at a constant speed along the gold removing direction, the tin wave infiltrates the chip pin gold removing sections in sequence, the gold removing and tin coating operation of the gold-plated chip is completed at one time, and the principle and the process of the gold removing and tin coating are shown in fig. 5.
Step three, for the packaged chip with pins on two sides, the gold and tin removing process of the chip pins leaking from two sides of the pressing strip can be completed at one time; and for the packaged chip with pins on four sides, gold and tin removing operation needs to be carried out twice, the gold and tin removing operation for the first time is the same as that for the packaged chip with pins on two sides, the gold and tin removing operation for the second time only needs to rotate all the pressing strips by 90 degrees for fastening, so that the pins of the chip leaking from two sides of the pressing strips are not subjected to gold and tin removing, the processes of feeding, soldering flux spraying, preheating, gold and tin removing and blanking are completed again, and the gold and tin removing operation for all the pins of the packaged chip with pins on four sides is completed. Different chips have different preheating temperatures, tin wave temperatures and gold removal speeds.
A typical process for automatically removing gold plating layers on two sides or four sides of a mounted chip pin such as QFP, QFN, SOP and the like is shown in fig. 6 and 7. Typical paths for gold removal of mounted chips with pins on two sides or four sides, such as QFP, QFN, SOP, etc., are shown in fig. 8 and 9.
The tool and the method for automatically removing the gold plating layer on the pins of the surface-mounted chips with pins on two sides or four sides, such as QFP, QFN, SOP and the like, have the advantages of simplicity in operation, wide applicability, low cost and the like, and have important significance for improving the gold removing efficiency and the welding quality of the surface-mounted chips with pins on two sides or four sides, such as QFP, QFN, SOP and the like.
It should be understood that equivalents and modifications of the technical solution and inventive concept thereof may occur to those skilled in the art, and all such modifications and alterations should fall within the scope of the appended claims.
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