Reflow soldering curve determination method

Abstract

The invention discloses a reflow soldering curve measuring method. The method comprises the steps that S1, a temperature measuring plate is manufactured; the temperature measuring plate comprises an aluminum substrate, a device is fixedly arranged above the aluminum substrate by smearing silver adhesive, a thermocouple is arranged on the device, the front end of the thermocouple is fixedly arranged on a device body through conductive adhesive, and a wire body on the thermocouple is fixed through high-temperature-resistant adhesive tape. One end, far away from the thermocouple, of the wire body is connected to a furnace temperature measuring instrument, and the surface temperature of the device is detected and recorded in the measuring process; s2, measuring a curve; and S3, data management. The invention belongs to the field of reflow soldering curve measuring methods, and particularly relates to a reflow soldering curve measuring method. According to the method, by designing and combining existing test methods, furnace temperature curves of reflow corresponding to devices of different packaging types are innovated on the basis of IPC-JEDEC J-STD-020F-2022 Moisture Reflow Sensitivity for Non-Hermetic Surface Mount Devices (SMDs), and the accuracy rate of selecting the reflow curve during a pretreatment test is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of reflow soldering curve measurement methods, and specifically refers to a reflow soldering curve measurement method. Background Art

[0002] In the field of modern electronic product manufacturing, with the development of electronic devices towards miniaturization and high performance, surface mount technology (SMT) has been widely used. As a key link in the SMT process, reflow soldering undertakes the important task of reliably connecting electronic components to printed circuit boards (PCBs). The quality of its soldering directly affects the electrical performance, mechanical performance, and long-term reliability of electronic products. The reflow soldering process realizes the metallurgical bonding between components and PCB pads by precisely controlling the temperature of the soldering area, enabling the solder to go through stages such as preheating, heating up, reflowing, and cooling. In this process, the reflow soldering curve (i.e., the curve of temperature changing with time) plays a decisive role. A suitable reflow soldering curve can ensure that the solder fully melts, wets the component pins and PCB pads, forming good solder joints and avoiding defects such as solder bridging, cold soldering, and solder joint cracking. On the contrary, an unreasonable reflow soldering curve may lead to poor soldering, increasing the defective rate of products and even affecting the efficiency and cost of the entire production process. Traditional reflow soldering curve measurement methods mainly rely on temperature sensors such as thermocouples for single-point temperature measurement, and data storage is carried out through manual recording or simple data acquisition devices. This method has many limitations: First, single-point measurement cannot comprehensively reflect the temperature distribution in the soldering area, easily overlooking local overheating or overcooling phenomena; second, manual data recording is not only inefficient but also prone to introducing human errors; third, simple data acquisition devices often lack data analysis and processing functions, making it difficult to deeply evaluate and optimize the reflow soldering curve. With the continuous refinement and complexity of electronic product manufacturing processes, higher requirements are put forward for the accuracy, comprehensiveness, and intelligence of reflow soldering curve measurement methods. Summary of the Invention

[0003] In view of the above situation, to overcome the defects of the prior art, the present invention provides a reflow soldering curve measurement method, effectively solving the problem that there is no clear specific temperature setting and speed setting in the current market, but only general temperature and time requirements are given according to three major classifications: eutectic packaging (SnPb), lead-free packaging (SAC alloy), and LTS packaging (LTS alloy), resulting in the need for operators to re-evaluate the temperature zone temperature and speed according to the standard each time; and the key points for making the temperature measurement board are not given. The traditional method uses FR4 and ceramic substrates and fixes the thermocouple by welding, resulting in inconvenient sample picking and placing, and the FR4 substrate needs to be customized according to the packaging.

[0004] The technical solution adopted by the present invention is as follows: The present invention proposes a reflow soldering curve measurement method.

[0005] Further, it includes manufacturing a temperature measuring plate: the temperature measuring plate includes an aluminum substrate (1), a device is fixedly arranged above the aluminum substrate (1) through a colloid, a thermocouple (2) is arranged on the device, the front end of the thermocouple (2) is fixedly arranged on the device body through a conductive adhesive, the wire body on the thermocouple (2) is fixed through a high-temperature resistant tape (3), and one end of the wire body is connected to a furnace temperature measuring instrument. The thermocouple detects the surface temperature of the device during the measurement process, and the furnace temperature measuring instrument records the surface temperature of the device during the measurement process.

[0006] Temperature setting is carried out according to the device packaging form.

[0007] Determining the curve: The temperature measuring plate is connected to the measuring instrument, and the measuring instrument and the temperature measuring plate are placed into the reflow oven cavity together. The measuring instrument is used to record the surface temperature of the device detected by the thermocouple (2).

[0008] Generating the curve: Read the surface temperature of the device detected by the thermocouple (2) recorded by the measuring instrument, and use software to automatically generate a furnace temperature curve.

[0009] Integrating the database: Name it according to the packaging form and volume, upload the database for subsequent use.

[0010] Further, the temperature setting includes, based on the device packaging form, since devices with different volumes have different heat absorption speeds, different volume ranges are used to divide different volume intervals to classify products with different volumes, and different volume ranges correspond to one temperature measuring plate and a corresponding temperature curve, thereby greatly reducing the number and cost of the temperature measuring plates.

[0011] Further, the generating the curve includes reading the temperature record recorded in the furnace temperature tester by a computer and using software to automatically generate a furnace temperature curve.

[0012] Further, the integrating the database includes integrating the furnace temperature curves of devices with the same packaging form and different volume ranges, naming them according to the packaging form and volume, and uploading them to the database for storage. They can be downloaded and used when needed.

[0013] Further, the colloid includes silver glue.

[0014] The beneficial effects obtained by the present invention with the above structure are as follows: This solution proposes a method for determining the reflow curve. This method replaces the original mode with an innovative temperature measuring plate manufacturing mode, improves the speed and efficiency, and experimenters can quickly find the corresponding furnace temperature curve setting method, shortening the determination time of the furnace temperature curve. By intuitively selecting the furnace temperature curve in the database, doubts from the client are eliminated, providing confidence for the conclusions of the laboratory. Brief Description of the Drawings

[0015] Figure 1 Schematic diagram of the temperature measurement board for a reflow soldering curve measurement method proposed by the present invention;

[0016] Figure 2 Schematic diagram of the furnace temperature curve for a reflow soldering curve measurement method proposed by the present invention;

[0017] Wherein, 1, aluminum substrate; 2, thermocouple; 3, high-temperature resistant tape.

[0018] The drawings are used to provide further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention. Detailed Embodiments

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0021] As Figure 1 - Figure 2 shown, the present invention proposes a reflow soldering curve measurement method, including:

[0022] The temperature measurement board includes an aluminum substrate 1. The aluminum substrate 1 serves as the basic carrier of the temperature measurement board, has good thermal conductivity and mechanical strength, ensures the accuracy of temperature measurement. Above the aluminum substrate 1, a device is fixedly arranged by applying silver paste. The silver paste has excellent electrical conductivity, can transfer the heat generated by the device to the aluminum substrate 1, reduce the thermal resistance, and improve the accuracy of temperature measurement. A thermocouple 2 is arranged on the device. When there is a temperature difference at both ends of the thermocouple 2, a thermoelectric potential will be generated. By measuring the magnitude of the thermoelectric potential, the temperature value can be accurately obtained.

[0023] The front end of the thermocouple 2 is fixedly arranged on the device body through conductive adhesive. The use of the conductive adhesive not only ensures good electrical connection between the thermocouple 2 and the device, but also ensures close contact between the thermocouple 2 and the device surface, so as to accurately measure the temperature of the device surface. The wire on the thermocouple 2 is fixed by a high-temperature resistant tape 3. The high-temperature resistant tape 3 can withstand the high-temperature environment in the reflow soldering furnace, prevent the wire from loosening or falling off at high temperature, and ensure the stability of the signal transmission of the thermocouple 2. And the end of the wire far away from the thermocouple 2 is connected to the furnace temperature measuring instrument. During the measurement process, the thermocouple 2 converts the temperature of the device surface into an electrical signal and transmits it to the furnace temperature measuring instrument through the wire. The furnace temperature measuring instrument processes and records these electrical signals to realize the detection and recording of the temperature of the device surface.

[0024] The device manufactures temperature measurement plates according to different volume sizes to meet the requirements of temperature curves of devices with different volumes. The thermal characteristics of devices with different volumes vary greatly during the reflow soldering process. Devices with larger volumes have a larger heat capacity and a relatively slower heating rate; while devices with smaller volumes have a smaller heat capacity and a faster heating rate. Therefore, it is necessary to manufacture temperature measurement plates according to the volume sizes of the devices respectively.

[0025] Examples of the volume size range division are as follows: 1. Volume range: 0 - 10mm 3 ; 2. Volume range: 10 - 100mm 3 ; 3. Volume range: 100 - 350mm 3 .

[0026] Based on the component packaging form, due to the different heat absorption speeds of devices with different volumes, different volume intervals are divided by different volume ranges to classify products with different volumes. Different volume ranges adopt a corresponding temperature measurement plate and a corresponding temperature curve, avoiding manufacturing a temperature measurement plate for each device with a different volume, thereby greatly reducing the number and cost of temperature measurement plates.

[0027] The temperature measurement plate is connected to the furnace temperature measuring instrument. When measuring the temperature, ensure that the connection between the furnace temperature measuring instrument and the temperature measurement plate is firm and the signal transmission is normal. Put the temperature measuring instrument and the test plate into the reflow soldering furnace cavity together. The reflow soldering furnace usually has multiple temperature zones, and the temperature and time of each temperature zone can be set according to the process requirements. During the reflow soldering process, the temperature of the device surface detected by the thermocouple 2 is recorded through each temperature zone. The furnace temperature measuring instrument samples and records the temperature signals transmitted by the thermocouple 2 at certain time intervals to form a series of temperature data.

[0028] Read the temperature records stored in the furnace temperature tester through a computer, and transfer the data through a USB interface or other communication methods. Use professional software to automatically generate a furnace temperature curve. This software can process and analyze the read temperature data, and draw an intuitive furnace temperature curve based on the corresponding relationship between time and temperature. The furnace temperature curve can clearly reflect the temperature change of the device during the reflow soldering process, including the heating stage, holding stage, reflow stage, and cooling stage, etc.

[0029] By integrating the furnace temperature curves of devices with the same package form and different volume ranges, naming them according to the package form and volume. During the integration process, a large amount of furnace temperature curve data needs to be screened and classified. Group the furnace temperature curves of devices with the same package form and different volume ranges into one category, which is convenient for managing and querying the furnace temperature curves, and at the same time facilitates comparing the temperature characteristics of different batches or different models of devices.

[0030] Upload the integrated furnace temperature curve to the database for storage. The database can use professional database management systems such as MySQL, Oracle, etc. to ensure the security and reliability of the data. It can be downloaded and used when needed. Engineers can download the corresponding furnace temperature curve from the database according to actual needs for temperature monitoring and process adjustment during the production process, improving production efficiency and product quality.

[0031] The method of making temperature measurement boards based on the classification of devices with different volumes and managing temperature curves has significant advantages. In terms of cost, it greatly reduces the number of temperature measurement boards and lowers the production and maintenance costs; in terms of efficiency, it improves the efficiency of temperature measurement and analysis through automated data collection and curve generation; in terms of quality control, accurate furnace temperature curves can help engineers promptly discover temperature anomalies during the production process and ensure the welding quality of products.

[0032] The above is the overall working process of the present invention. Just repeat these steps the next time it is used.

[0033] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0034] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

[0035] The above description of the present invention and its embodiments is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. In general, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the present invention, design similar structural forms and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present invention.

Claims

1. A method for measuring a reflow soldering curve, characterized in that: Including: Manufacturing a temperature measurement board: The temperature measurement board includes an aluminum substrate (1). A device is fixedly arranged above the aluminum substrate (1) through a colloid. A thermocouple (2) is arranged on the device. The front end of the thermocouple (2) is fixedly arranged on the device body through a conductive adhesive. The wire on the thermocouple (2) is fixed through a high-temperature resistant tape (3), and one end of the wire is connected to a furnace temperature measuring instrument. The thermocouple detects the surface temperature of the device during the measurement process, and the furnace temperature measuring instrument records the surface temperature of the device during the measurement process. Temperature setting, performing the temperature setting according to the device packaging form. Measuring the curve, connecting the temperature measurement board to the temperature measuring instrument, and putting the temperature measuring instrument and the temperature measurement board into the reflow soldering furnace cavity together. The temperature measuring instrument is used to record the surface temperature of the device detected by the thermocouple (2). Generating the curve, reading the surface temperature of the device detected by the thermocouple (2) recorded by the temperature measuring instrument, and automatically generating a furnace temperature curve using software. Integrating the database, naming it according to the packaging form and volume, uploading the database for subsequent use.

2. The method for measuring a reflow soldering curve according to claim 1, wherein: The temperature setting includes, based on the device packaging form, since the heat absorption speeds of devices with different volumes are different, dividing different volume ranges into different volume intervals to classify products with different volumes, and corresponding one temperature measurement board and a corresponding temperature curve are adopted for different volume ranges, thereby greatly reducing the number and cost of the temperature measurement boards.

3. A method for measuring a reflow soldering curve according to claim 1, characterized in that: The generating the curve includes reading the temperature record recorded in the furnace temperature tester by a computer and automatically generating a furnace temperature curve using software.

4. A method for measuring a reflow soldering curve according to claim 1, characterized in that: The integrating the database includes integrating the furnace temperature curves of devices with the same packaging form and different volume ranges, naming them according to the packaging form and volume, and uploading and saving them to the database for downloading and use when needed.

5. A method for measuring a reflow soldering curve according to claim 1, characterized in that: The colloid includes silver glue.

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