Device and method for testing firmness of lead of high-density QFN (quad flat no-lead) packaging device

Abstract

The invention provides a high-density QFN packaging device lead firmness testing device, and the device comprises a clamping assembly which is used for fixing a QFN packaging device, and the QFN packaging device is provided with a plurality of bonding pads; the cover plate abuts against the surface, provided with the bonding pads, of the QFN packaging device, a plurality of preformed holes are formed in the cover plate, and each preformed hole is opposite to the corresponding bonding pad of the QFN packaging device in position and used for framing the bonding pad, so that isolation between the bonding pads is achieved, welding connection between the bonding pads is avoided in the subsequent process that leads are welded to the bonding pads, and the quality of the bonding pads is improved. Therefore, the test accuracy is improved.

Description

Technical Field

[0001] The present application relates to the technical field of QFN package device testing devices, and in particular to a high-density QFN package device lead firmness testing device and a testing method. Background Art

[0002] The identification test and structural analysis and evaluation of QFN packaged devices usually require the component lead firmness test. The test method is to select a wire with a diameter that is very close to but does not exceed the nominal pad width and weld it to the pad at the bottom of the QFN packaged component. The wire is perpendicular to the welding plane and the welded wire is pulled to test the firmness of the pad at the bottom of the QFN packaged component. However, with the development of miniaturization and multi-function of QFN packaged devices, the distribution density of pads at the bottom of QFN packaged devices is getting higher and higher. Therefore, in the process of wire strength test, multiple pads may be welded together, which will affect subsequent tests. Summary of the invention

[0003] In view of this, the purpose of the present application is to provide a high-density QFN package device lead firmness test device and test method to solve the problem of welding connection between multiple pads during the process of wire bonding firmness test.

[0004] Based on the above purpose, the present application provides a high-density QFN package device lead firmness testing device, comprising:

[0005] A clamping assembly is used to fix a QFN packaged device, on which a plurality of pads are provided;

[0006] A cover plate is provided, the cover plate abuts against the surface of the QFN package device provided with a solder pad, and a plurality of reserved holes are provided on the cover plate, each of the reserved holes is opposite to a solder pad position of the QFN package device, and is used to frame the solder pad.

[0007] Optionally, a solder resist layer is provided on the cover plate.

[0008] Optionally, the clamping assembly includes four groups of clamping structures, which are respectively located on different sides of the QFN packaged device. The clamping structure includes a driving member and a clamping plate. The driving member drives the clamping plate to extend and retract to control the clamping plate to abut against the side of the QFN packaged device.

[0009] Optionally, a mounting plate is also included for placing the QFN packaged device and for mounting the clamping assembly.

[0010] Optionally, a fixing assembly is also included, which includes a vertical rod, a horizontal rod and a fixing bolt, the vertical rod is fixedly connected to the mounting plate, the horizontal rod is rotatably connected to the top of the vertical rod, and the fixing bolt passes through the horizontal rod and abuts the cover plate.

[0011] Optionally, the driving components are air cylinders or hydraulic cylinders, and the control system controls the driving components to operate simultaneously.

[0012] Based on the same inventive concept, the present disclosure also provides a method for testing the robustness of bonding wires of a high-density QFN packaged device, which is applied to the above-mentioned testing device and includes the following steps:

[0013] The clamping assembly fixes the QFN package device and exposes the pad of the QFN package device;

[0014] Tin is uniformly coated on all pads of the QFN package device. After the tin cools down, the cover is placed on the QFN package device, and each reserved hole is aligned with a pad of the QFN package device;

[0015] Pass the solder wire through the reserved hole, overlap the head of the solder wire on the tinned position of the QFN package device pad, and use hot melt adhesive to fix the tail of the solder wire to the upper surface of the cover;

[0016] The test device passes through a reflow oven, where the high temperature melts the tin. After the tin melts, the test device is taken out, and after the tin cools down, the solder wire and the solder pad are soldered.

[0017] Melt the hot melt adhesive on the upper surface of the cover plate to separate the welding wire from the cover plate;

[0018] Take out the QFN packaged device from the test device, straighten the bonding wires, and perform a lead firmness test on the QFN packaged device.

[0019] Optionally, the temperature in the reflow oven is 130-140° C., and the residence time of the test device in the reflow oven is 80-90 seconds.

[0020] From the above description, it can be seen that the present application provides a high-density QFN package device lead firmness testing device, including a clamping assembly and a cover plate, the clamping assembly is used to fix the QFN package device, and make the bottom of the QFN package device face upward to expose all pads, which is convenient for subsequent welding of wires, and the cover plate abuts the surface of the QFN package device with pads, and each of the reserved holes is opposite to a QFN package device pad position, so as to frame the pad, thereby achieving isolation between the pads, and in the subsequent process of welding the leads to the pads, the pads are prevented from being welded together, thereby improving the accuracy of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is a schematic diagram of the structure of the test device for this application;

[0023] Figure 2 This is a schematic diagram showing the structure of the cover plate in an embodiment of the present application;

[0024] Figure 3 A schematic diagram showing a fixing assembly according to an embodiment of the present application;

[0025] Figure 4 Flow chart of the test method in this application.

[0026] Figure numerals: 1. clamping assembly; 11. clamping structure; 111. driving member; 112. clamping plate; 2. QFN package device; 21. solder pad; 3. cover plate; 31. reserved hole; 4. mounting plate; 5. fixing assembly; 51. vertical rod; 52. horizontal rod; 53. fixing bolt. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0028] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0029] Based on the background, QFN package is one of the commonly used packaging forms in surface mount technology. It is widely used in the field of integrated circuit packaging. Due to its unique characteristics and advantages, it has become one of the preferred packaging solutions in the design of many electronic devices. QFN packaged components usually appear in the form of pads on four sides and no exposed pins, in a square or rectangular shape. The bottom of the QFN packaged components is equipped with conductive surfaces around to achieve electrical connection with external devices. QFN packaged components are light, thin, and easy to integrate, which gives them many advantages in terms of space utilization efficiency, heat dissipation performance, and circuit layout.

[0030] With the development of Moore's Law and the demand for miniaturization of electronic devices, higher requirements are placed on the integrated functions and size of integrated circuit chips. Under this premise, the packaging area of ​​QFN packaged components is reduced and the number of pads is increased.

[0031] The identification test and structural analysis and evaluation of QFN packaged devices usually require the component lead firmness test. The test method is to select a wire with a diameter that is very close to but does not exceed the nominal pad width and weld it to the pad at the bottom of the QFN packaged component. The wire is perpendicular to the welding plane and the welded wire is pulled to test the firmness of the pad at the bottom of the QFN packaged component. However, with the development of miniaturization and multi-function of QFN packaged devices, the distribution density of pads at the bottom of QFN packaged devices is getting higher and higher. Therefore, in the process of wire bond firmness test, multiple pads may be welded together, which will affect the subsequent wire bond firmness test.

[0032] The following is combined with Figure 1-4 The embodiments of the present application will be described in detail.

[0033] A high-density QFN package device lead firmness test device, such as Figure 1 and Figure 2 As shown, including:

[0034] A clamping assembly 1 is used to fix a QFN package device 2, and a plurality of pads 21 are provided on the QFN package device 2;

[0035] The cover plate 3 abuts against the surface of the QFN package device 2 provided with the solder pad 21 , and a plurality of reserved holes 31 are provided on the cover plate 3 , each of the reserved holes 31 is opposite to a solder pad 21 of the QFN package device 2 , and is used to frame the solder pad 21 .

[0036] Specifically, a plurality of pads 21 are provided at the bottom of the QFN package device 2, and the clamping assembly 1 fixes the QFN package device 2 so that the bottom of the QFN package device 2 faces upward to expose all pads 21, which is convenient for subsequent welding of wires. A pressure sensor can be embedded in the clamping assembly 1 to monitor and feedback the clamping force of the QFN package device 2 in real time, so as to avoid damage to the QFN package device 2 due to excessive clamping, and ensure the safety of the QFN package device 2 during the test.

[0037] In addition, the number and positions of the reserved holes 31 on the cover plate 3 are custom designed according to the number and positions of the pads 21 of the QFN packaged device 2, ensuring that the reserved holes 31 on the cover plate 3 correspond one-to-one and are positioned relative to the pads 21 on the QFN packaged device 2, and the reserved holes 31 frame the pads 21 to achieve isolation between the pads 21.

[0038] In this embodiment, the clamping assembly 1 is used to fix the QFN packaged device 2 and make the bottom of the QFN packaged device 2 face upward to expose all the pads 21 for subsequent welding of wires. The cover plate 3 abuts the surface of the QFN packaged device 2 provided with the pads 21, and each of the reserved holes 31 is opposite to a pad 21 of the QFN packaged device 2 to frame the pads 21, thereby achieving isolation between the pads 21. In the process of subsequent lead welding to the pads 21, welding connection between the pads 21 is avoided, thereby improving the accuracy of the test.

[0039] In some embodiments, a solder resist layer is disposed on the cover plate 3 .

[0040] Specifically, the cover plate 3 is coated with a solder resist layer, which not only covers the planar area of ​​the cover plate 3, but also covers the side walls of the reserved holes 31, thereby preventing the cover plate 3 and the pad 21 from being welded together and affecting the normal progress of the test. The solder resist layer can be a solder resist coating, which is applied to the cover plate 3 by spraying, brushing or dipping. The solder resist layer can also be a solder resist film, which is deposited on the cover plate 3 by hot pressing or vacuum coating.

[0041] In this embodiment, the solder resist layer can prevent the cover plate 3 and the pads 21 from being welded together, and can further prevent the pads 21 from being welded together, thereby improving the accuracy and authenticity of the test.

[0042] In some embodiments, Figure 1 and Figure 2 As shown, the clamping assembly 1 includes four groups of clamping structures 11, which are respectively located on different sides of the QFN package device 2. The clamping structure 11 includes a driving member 111 and a clamping plate 112. The driving member 111 drives the clamping plate 112 to extend and retract to control the clamping plate 112 to abut against the side of the QFN package device 2.

[0043] In addition, the driving member 111 is a cylinder or a hydraulic cylinder, and the control system controls the driving members 111 to run simultaneously.

[0044] Specifically, Figure 2 and Figure 3 As shown, the cover plate 3 is placed on the QFN package device 2 and on four clamping plates 112, thereby improving the stability of the cover plate 3. A layer of elastic buffer material, such as a rubber pad or a silicone pad, can be arranged between the clamping plate 112 and the QFN package device 2 to absorb the impact force during the clamping process and protect the QFN package device 2 from damage.

[0045] In addition, the control system automatically adjusts the extension speed and strength of the driving member 111 to achieve precise clamping control. The control system can be equipped with a human-machine interaction platform to facilitate operators to monitor the clamping state, adjust clamping parameters and view fault information.

[0046] In this embodiment, four groups of clamping structures 11 are respectively arranged on different sides of the QFN packaged device 2 to achieve four-side clamping of the QFN packaged device 2, thereby improving the clamping stability of the QFN packaged device 2. The clamping structure 11 includes a driving member 111 and a clamping plate 112. The control system controls the telescopic length of the output shaft of the driving member 111 according to the size of the QFN packaged device 2. Therefore, the above-mentioned clamping structure 11 can clamp QFN packaged devices 2 of different sizes, thereby improving the applicability of the test device.

[0047] In some embodiments, Figure 1 and Figure 2 As shown, a high-density QFN package device lead firmness testing device also includes a mounting plate 4 for placing the QFN package device 2 and for mounting the clamping assembly 1.

[0048] In this embodiment, the clamping assembly 1 is mounted on the mounting plate 4, and the QFN packaged device 2 is also placed on the mounting plate 4, so that the entire test device can be moved conveniently according to test requirements, thereby improving the portability of the test device.

[0049] In some embodiments, Figure 2 and Figure 3 As shown, a high-density QFN package device lead firmness testing device also includes a fixing component 5, which includes a vertical rod 51, a horizontal rod 52 and a fixing bolt 53. The vertical rod 51 is fixedly connected to the mounting plate 4, the horizontal rod 52 is rotatably connected to the top of the vertical rod 51, and the fixing bolt 53 passes through the horizontal rod 52 and abuts the cover plate 3.

[0050] Specifically, the fixing components 5 can be arranged into four groups, which are respectively arranged on one side of the QFN packaged device 2, so as to improve the stability of the QFN packaged device 2 and the cover plate 3 during the test process.

[0051] In this embodiment, the fixing assembly 5 allows the cover plate 3 to press the QFN package device 2, thereby improving the stability of the QFN package device 2 and the cover plate 3 during the test, and preventing the tin liquid from flowing between the gap between the cover plate 3 and the QFN package device 2, causing the pad 21 to be connected, thereby affecting the test effect. By adjusting the tightness of the fixing bolts 53, the cover plate 3 is firmly pressed on the QFN package device 2, and the fixing efficiency is relatively high.

[0052] Based on the same inventive concept, corresponding to the test device of any of the above embodiments, the present application also provides a method for testing the lead firmness of a high-density QFN package device, comprising the following steps:

[0053] S101: The clamping assembly 1 fixes the QFN package device 2 and exposes the pad 21 of the QFN package device 2;

[0054] S102: uniformly coating all pads 21 of the QFN package device 2 with tin, and after the tin cools down, placing the cover plate 3 on the QFN package device 2, and each reserved hole 31 is aligned with a pad 21 of the QFN package device 2;

[0055] S103: insert the welding wire into the reserved hole 31, overlap the head of the welding wire on the tinned position of the pad 21 of the QFN package device 2, and fix the tail of the welding wire to the upper surface of the cover plate 3 with hot melt adhesive;

[0056] S104: The test device passes through a reflow furnace, where the high temperature melts the tin. After the tin melts, the test device is taken out, and after the tin cools down, the solder wire and the solder pad are soldered.

[0057] S105: Melting the hot melt adhesive on the upper surface of the cover plate 3 to separate the welding wire from the cover plate 3;

[0058] S106 : taking out the QFN packaged device 2 from the testing device, straightening the bonding wires, and performing a lead firmness test on the QFN packaged device 2 .

[0059] In this embodiment, in step S101 , the clamping assembly 1 fixes the QFN packaged device 2 and exposes the pad 21 , thereby effectively preventing the QFN packaged device 2 from moving during the tinning, welding and other processes.

[0060] In step S102, all pads 21 of the QFN package device 2 are uniformly coated with tin, which helps to form a uniform welding interface in the subsequent steps. At the same time, the cover plate 3 is placed on the QFN package device 2, and it is ensured that each reserved hole 31 is aligned with a pad 21, which provides a basis for the accurate placement of the welding wire, and the reserved hole 31 frames the pad 21, thereby achieving isolation between the pads 21. In the process of subsequent lead welding to the pad 21, the pads 21 are prevented from being welded together, thereby improving the accuracy of the test.

[0061] In step S103, the welding wire that passes through the reserved hole 31 overlaps the tin-coated position of the welding pad 21, and uses hot melt adhesive to fix the tail of the welding wire to the upper surface of the cover plate 3. This method can ensure that the welding wire remains stable during the welding process to avoid movement or dislocation.

[0062] In step S104, the tin is melted by the high temperature of the reflow furnace to form a firm welding connection between the welding wire and the pad 21. By welding the welding wire in the reflow furnace, the consistency and reliability of welding can be ensured, thereby achieving precise welding, which is suitable for high-density QFN packaging devices 2.

[0063] In step S105 , the hot melt adhesive on the upper surface of the cover plate 3 is melted to separate the welding wire from the cover plate 3 . This step is to remove the cover plate 3 without affecting the connection between the welding wire and the welding pad 21 , so as to facilitate subsequent testing.

[0064] In summary, compared with manual welding, the welding method in the present application has a high degree of automation, good welding consistency and stability, thereby improving the efficiency and accuracy of the test.

[0065] In some embodiments, the temperature in the reflow oven is 130-140° C., and the residence time of the test device in the reflow oven is 80-90 seconds.

[0066] Specifically, the test device is made of a high temperature resistant material. The test device made of a high temperature resistant material can withstand the high temperature environment in the reflow oven without affecting the accuracy of the test due to thermal expansion, softening or deformation.

[0067] In an embodiment of the present application, the temperature in the reflow oven is 130-140°C, and the residence time of the test device in the reflow oven is 80-90s. The above temperature range and residence time range can ensure that the solder is completely melted without causing thermal damage to the packaged components or the test device.

[0068] In summary, the present application provides a high-density QFN package device 2 lead firmness test device, including a clamping assembly 1 and a cover plate 3, the clamping assembly 1 is used to fix the QFN package device 2, and make the bottom of the QFN package device 2 face upward to expose all the pads 21, which is convenient for subsequent welding of welding wires, the cover plate 3 abuts against the surface of the QFN package device 2 provided with the pads 21, and each of the reserved holes 31 is opposite to a QFN package device 2 pad 21 position, used to frame the pad 21, so as to achieve isolation between the pads 21, in the process of subsequent lead welding to the pad 21, the pads 21 are prevented from being welded together, thereby improving the accuracy of the test;

[0069] The clamping assembly 1 in the present application includes four groups of clamping structures 11, which are respectively arranged on different sides of the QFN package device 2 to achieve four-side clamping of the QFN package device 2, thereby improving the clamping stability of the QFN package device 2. The clamping structure 11 includes a driving member 111 and a clamping plate 112. The control system controls the telescopic length of the output shaft of the driving member 111 according to the size of the QFN package device 2. Therefore, the above-mentioned clamping structure 11 can clamp QFN package devices 2 of different sizes, thereby improving the applicability of the test device;

[0070] The test device in the present application further includes a fixing assembly 5, which can be arranged in four groups and respectively arranged on one side of the QFN package device 2. The fixing assembly 5 enables the cover plate 3 to press the QFN package device 2, thereby improving the stability of the QFN package device 2 and the cover plate 3 during the test process, and can prevent the tin liquid from flowing in the gap between the cover plate 3 and the QFN package device 2, causing the pad 21 to be connected, thereby affecting the test effect;

[0071] The testing method in the present application uses a reflow oven to simultaneously weld the leads to the pads 21 on the QFN package device 2, thereby improving welding consistency and stability, thereby improving the efficiency and accuracy of the test.

[0072] A person skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0073] In addition, to simplify the description and discussion, and in order not to make the embodiments of the present application difficult to understand, the known power supply / ground connection with the integrated circuit chip and other components may or may not be shown in the provided drawings. In addition, the device can be shown in the form of a block diagram to avoid making the embodiments of the present application difficult to understand, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform to be implemented in the embodiments of the present application (that is, these details should be fully within the scope of understanding of those skilled in the art). In the case of elaborating specific details (e.g., circuits) to describe exemplary embodiments of the present application, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details or when these specific details are changed. Therefore, these descriptions should be considered to be illustrative rather than restrictive.

[0074] Although the present invention has been described in conjunction with specific embodiments of the present invention, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art based on the foregoing description.For example, other memory architectures may use the discussed embodiments.

[0075] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the present application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A high-density QFN package device (2) lead firmness testing device, characterized in that: include: A clamping assembly (1) for fixing a QFN packaged device (2), wherein a plurality of pads (21) are provided on the QFN packaged device (2); A cover plate (3), the cover plate (3) abutting against a surface of a QFN package device (2) provided with a solder pad (21), the cover plate (3) being provided with a plurality of reserved holes (31), each of the reserved holes (31) being opposite to a solder pad (21) of a QFN package device (2) and being used to frame the solder pad (21).

2. A high-density QFN package device (2) lead firmness testing device according to claim 1, characterized in that: A solder resist layer is provided on the cover plate (3).

3. A high-density QFN package device (2) lead firmness testing device according to claim 1, characterized in that: The clamping assembly (1) comprises four groups of clamping structures (11), which are respectively located on different sides of the QFN package device (2); the clamping structure (11) comprises a driving member (111) and a clamping plate (112); the driving member (111) drives the clamping plate (112) to extend and retract, so as to control the clamping plate (112) to abut against the side of the QFN package device (2).

4. A high-density QFN package device (2) lead firmness testing device according to claim 3, characterized in that: It also includes a mounting plate (4) for placing the QFN packaged device (2) and for mounting the clamping assembly (1).

5. A high-density QFN package device (2) lead firmness testing device according to claim 4, characterized in that: The invention also comprises a fixing assembly (5), wherein the fixing assembly (5) comprises a vertical rod (51), a horizontal rod (52) and a fixing bolt (53), wherein the vertical rod (51) is fixedly connected to the mounting plate (4), the horizontal rod (52) is rotatably connected to the top of the vertical rod (51), and the fixing bolt (53) passes through the horizontal rod (52) and abuts against the cover plate (3).

6. A high-density QFN package device (2) lead firmness testing device according to claim 3, characterized in that: The driving member (111) is a pneumatic cylinder or a hydraulic cylinder, and the control system controls the driving members (111) to operate simultaneously.

7. A method for testing the wire fastness of a high-density QFN packaged device (2), applied to the testing device according to claims 1-6, characterized in that: The following steps are involved: The clamping assembly (1) fixes the QFN package device (2) and exposes the pad (21) of the QFN package device (2); All pads (21) of the QFN package device (2) are uniformly coated with tin. After the tin cools down, the cover plate (3) is placed on the QFN package device (2), and each reserved hole (31) is aligned with a pad (21) of the QFN package device (2); Pass the welding wire through the reserved hole (31), overlap the head of the welding wire on the tinned position of the welding pad (21) of the QFN package device (2), and use hot melt adhesive to fix the tail of the welding wire to the upper surface of the cover plate (3); The test device passes through a reflow furnace, where the high temperature melts the tin. After the tin melts, the test device is taken out, and after the tin cools, the solder wire is soldered to the solder pad (2). Melting the hot melt adhesive on the upper surface of the cover plate (3) to separate the welding wire from the cover plate (3); The QFN packaged device (2) is taken out from the testing device, the bonding wire is straightened, and a lead firmness test is performed on the QFN packaged device (2).

8. A method for testing the wire fastness of a high-density QFN packaged device (2) according to claim 7, characterized in that: The temperature in the reflow oven is 130-140°C, and the residence time of the test device in the reflow oven is 80-90s.

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