Simulation test method based on non-collapse solder ball BGA device weldability test

Abstract

The invention provides a simulation test method based on a non-collapse solder ball BGA device weldability test, and relates to the technical field of BGA device welding, and the method comprises the following steps: S1, solder ball water vapor aging; s2, solder ball drying: performing high-temperature baking in a dry environment; s3, solder paste is applied to the solder ball to prepare a sample, and reflow soldering is conducted on the prepared sample; a proper amount of soldering paste consistent in shape is directly printed on the non-collapse solder ball BGA solder ball through a soldering paste applying tool, and the soldering paste at least covers 50% of the surface of the solder ball; according to the invention, the whole preparation process is more convenient, and the problem of solderability test failure caused by solder ball adhesion and the like cannot be formed, so that the sample preparation efficiency and the solderability test success rate are improved, and the cost increased by preparing samples in multiple tests is also reduced; therefore, the success rate and the efficiency of the weldability test of the non-collapse solder ball BGA device are improved.

Description

Technical Field

[0001] This invention relates to the field of BGA device soldering technology, and more specifically to a simulation test method for solderability testing of BGA devices based on non-collapsed solder balls. Background Technology

[0002] With the rapid development of technology, electronic components are rapidly evolving towards high performance, high reliability, and miniaturization. Especially in high-end application fields such as military electronics, aerospace, and automotive electronics, stringent requirements for high performance, high reliability, and miniaturization are being placed on electronic products. Among these, BGA packaging has become a very important device packaging form, used in the packaging of high-reliability products such as T / R components.

[0003] Among them, ball grid array (BGA) devices are commonly packaged in ceramic or plastic. The former uses an integrated ceramic shell as the functional and structural carrier, and assembles bare chips and other electronic components inside. It achieves a hermetically sealed cover through parallel seam welding technology. The latter uses a carrier board to assemble the chip and then plastic encapsulates it. Finally, it uses solder balls at the bottom as external functional interfaces. When processing electronic components using BGA devices, the BGA devices are soldered to the circuit board through solder balls.

[0004] The solderability test for BGA devices generally refers to GJB7677-2012 "Test Methods for Ball Grid Arrays (BGAs)" to test the solderability during the soldering process. This involves printing solder on a non-metallized ceramic or glass substrate, aligning and mounting the device to be tested after moisture aging and drying onto the substrate, and melting the printed solder paste through a reflow process to simulate the surface soldering process of the device. The solderability is determined by the solder wetting condition of the solder balls, and the following solderability requirements must be met: 1) There should be no adhesion between solder balls; 2) The area of ​​the surface of the solder ball continuously covered with a new solder coating is less than 95%.

[0005] In existing BGA device solderability testing, it has been found that after simulated reflow soldering on unmetallized substrates, solder ball adhesion easily occurs. This is due to factors such as solder ball coplanarity, vibration, and solder wetting characteristics. Furthermore, the high density and close proximity of the solder balls make adhesion easy after the solder melts at high temperatures, leading to test failure and requiring repeated testing. This ultimately affects the success rate of BGA device solderability testing and increases testing costs. On the other hand, when using metallized ceramic or PCB substrates, BGA devices are soldered onto the metallized surface pads, making direct visual inspection impossible. The high solder strength also makes substrate removal time-consuming and laborious, easily causing solder balls to detach, leading to test failure and requiring repeated testing, ultimately affecting the success rate of BGA device solderability testing. Therefore, improving the success rate of BGA device solderability testing is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a simulation test method for solderability testing of BGA devices based on non-collapsed solder balls, which solves the problem of low success rate in current BGA device solderability testing.

[0007] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: This invention provides a simulation test method for solderability testing of non-collapsed solder ball BGA devices, comprising the following steps: S1. Moisture aging of welding balls; S2. Solder ball drying: High-temperature baking in a dry environment to remove moisture; S3. Apply solder paste to solder balls to prepare a sample, and then reflow solder the prepared sample. Among them, solder paste application involves directly printing an appropriate amount of solder paste with a consistent shape onto the solder balls of the non-collapsed solder ball BGA using a solder paste application tool, and the solder paste covers at least 50% of the solder ball surface; The melting point of solder balls is higher than that of solder paste. After applying solder paste, the non-collapsed solder ball BGA is placed with the solder ball face up on the reflow soldering tray fixture and reflow soldered directly. S4. Solderability visual inspection, used to determine the solderability of non-collapsed solder ball BGA devices.

[0008] Furthermore, in step S2: The dry environment atmosphere is a nitrogen environment.

[0009] Furthermore, in step S3, the solder paste is either Pb37Sn63 solder or Pb36Sn62Ag2 solder.

[0010] Furthermore, in step S4: During the visual inspection, the visual inspection is carried out under an optical microscope with magnification of 10x to 20x.

[0011] Furthermore, the BGA device in question is a plastic-encapsulated PBGA or a ceramic-encapsulated CBGA.

[0012] Furthermore, the solder balls in the non-collapsed solder balls are Pb90Sn10 solder balls, Pb80Sn20 solder balls, SnAg3.0Cu0.5 solder balls, or copper core balls.

[0013] Furthermore, the size range of the solder ball is φ0.3mm to φ1.2mm.

[0014] (III) Beneficial Effects This invention provides a simulation test method for solderability testing of BGA devices based on non-collapsed solder balls. Compared with existing technologies, it has the following advantages: The present invention uses the method of directly applying solder paste to the surface of BGA solder balls to complete the sample preparation. Compared with the existing method of printing solder paste and mounting devices on ceramic or PCB substrates, the whole preparation process is more convenient and will not cause solder ball adhesion and other phenomena that lead to failure of solderability test. It not only improves the efficiency of sample preparation and the success rate of solderability test, but also reduces the cost of repeated tests. Furthermore, the solder wetting condition of the reflowed samples can be directly observed under a microscope. The solder balls are not stuck together, and the solder wetting effect is easy to observe. Therefore, this invention improves the success rate of solderability testing for non-collapsed solder ball BGA devices, thereby improving the efficiency of solderability testing and reducing the cost of repeated tests. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 Flowchart for solderability testing in the soldering process of BGA devices; Figure 2 A schematic diagram illustrating the process of applying solder paste to a screen printing plate. Figure 3 This is a schematic diagram of the solder paste and solder before and after reflow soldering; Figure 4 This is an overall sample diagram of a weldability test performed using this process. Figure 5 This is a magnified view of a sample using this process; Figure 6 This is an overall sample diagram of a weldability test performed using existing processes. Figure 7 This is a magnified view of a sample using existing technology. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] This application provides a simulation test method for solderability testing of BGA devices based on non-collapsed solder ball, which solves the problem of low success rate in current BGA device solderability testing, improves solderability testing efficiency, and reduces the cost of repeated tests.

[0019] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0020] like Figures 1-3 As shown, a simulation test method for solderability testing of non-collapsed solder ball BGA devices includes the following steps: S1. Moisture aging of welding balls; S2. Solder ball drying: High-temperature baking in a dry environment to remove moisture; The drying environment is a nitrogen environment; S3. Apply solder paste to solder balls to prepare a sample, and then reflow solder the prepared sample. Among them, solder paste application involves directly printing an appropriate amount of solder paste with a consistent shape onto the solder balls of the non-collapsed solder ball BGA using a solder paste application tool, and the solder paste covers at least 50% of the solder ball surface; The melting point of solder balls is higher than that of solder paste. After applying solder paste, the non-collapsed solder ball BGA is placed with the solder ball face up on the reflow soldering tray fixture and reflow soldered directly. It should be noted that the solder paste application methods include, but are not limited to, screen printing, dotting and spraying, which reduces the problem of solder paste collapse and obvious peeling, resulting in exposed solder balls or solder paste forming connections between solder balls; The solder paste contains, but is not limited to, Pb37Sn63 solder and Pb36Sn62Ag2 solder; S4. Solderability visual inspection, used to determine the solderability of non-collapsed solder ball BGA devices; During the visual inspection, the visual inspection is carried out under an optical microscope with magnification of 10x to 20x.

[0021] It should be noted that, in the soldering process of non-collapsed ball BGA devices, the water vapor aging and drying treatment before the solderability test, as well as the reflow soldering parameters and appearance inspection of the solderability test, are carried out in accordance with the methods and conditions specified in the national military standard GJB7677. The solderability visual inspection specified in GJB7677 refers to determining solderability by observing the solder wetting condition on the surface of the solder balls after the printed solder paste has been melted during the reflow process. To achieve the solderability specified in GJB7677, the following requirements must be met: 1. There must be no sticking between the solder balls; 2. The area of ​​the surface of the solder ball that is continuously covered with a new solder coating is less than 95%.

[0022] The present invention uses the method of directly applying solder paste to the surface of BGA solder balls to complete the sample preparation. Compared with the existing methods of printing solder paste and mounting devices on ceramic or PCB substrates, the entire preparation process is more convenient, which not only improves the efficiency of sample preparation, but also reduces the cost of preparing the substrate for the experiment.

[0023] Furthermore, the solder wetting condition of the reflowed sample can be directly observed under a microscope, and the solder balls show no adhesion. Figure 4 and Figure 5 As shown in the example, it does not affect the determination of solderability; However, with existing methods, when mounting BGA devices on non-metallized ceramic or glass substrates, solder balls easily shift and stick together after reflow due to factors such as gravity, vibration, and the absence of metal on the substrate surface. Figure 6 and Figure 7 As shown in the example, the test result was a failure of the BGA device solderability test, which in turn affected the success rate of the non-collapsed solder ball BGA device solderability test and increased the cost of repeated tests. Therefore, this invention improves the success rate of solderability testing for non-collapsed solder ball BGA devices by using a simulation test method for solderability testing of non-collapsed solder ball BGA devices. The solder wetting effect is easy to observe, and there are no problems such as solder ball adhesion that affect the solderability determination. This improves the efficiency of solderability testing and reduces the cost of repeated tests.

[0024] Specifically, BGAs include, but are not limited to, plastic-encapsulated PBGAs and ceramic-encapsulated CBGAs; Non-collapsed solder balls include, but are not limited to, Pb90Sn10 solder balls, Pb80Sn20 solder balls, SnAg3.0Cu0.5 solder balls and copper core balls, and the solder balls do not melt during the welding process; The size range of the solder balls is φ0.3mm~φ1.2mm.

[0025] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0026] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for simulating a test of solderability of a non-collapsed solder ball (BGA) device, characterized by, The method comprises the following steps: S1, water vapor aging of the solder balls; S2, drying of the solder balls: high-temperature baking in a dry environment to remove water vapor; S3, applying solder paste to the solder balls to prepare a sample, and reflow soldering the prepared sample; The solder paste is applied by a solder paste application tool to print an appropriate amount of solder paste with consistent shape directly on the solder balls of the non-collapsed solder ball BGA, and the solder paste covers at least 50% of the surface of the solder balls; The melting point of the solder balls is higher than the melting point of the solder of the solder paste; The non-collapsed solder ball BGA with the applied solder paste is placed with the solder ball surface facing up on a reflow soldering tray tool for direct reflow soldering; S4, appearance inspection of solderability, used to determine the solderability of the non-collapsed solder ball BGA device.

2. A method for simulating a test of solderability of a non-collapsed solder ball BGA device as claimed in claim 1, wherein, In step S2: The dry environment atmosphere is a nitrogen environment.

3. A method for simulating a test of solderability of a non-solder ball collapse BGA device as claimed in claim 1, wherein, In step S3, the solder of the solder paste is Pb37Sn63 solder or Pb36Sn62Ag2 solder.

4. A method for simulating a test of solderability of a non-solder ball collapse BGA device as claimed in claim 1, wherein, In step S4: The appearance inspection is performed under a 10-20 times magnification optical microscope.

5. A method for simulating a test of solderability of a non-solder ball collapse BGA device as claimed in claim 1, wherein, The BGA device is a plastic package PBGA or a ceramic package CBGA.

6. A method for simulating a test of solderability of a non-collapsed solder ball BGA device according to any one of claims 1 to 5, wherein The solder balls in the non-collapsed solder ball BGA are Pb90Sn10 solder balls, Pb80Sn20 solder balls, SnAg3.0Cu0.5 solder balls, or copper core balls.

7. A method of simulating a test of solderability of a non-collapsed solder ball BGA device as defined in claim 6, wherein, The size of the solder balls ranges from φ0.3mm to φ1.2mm.

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