Automatic gold-tin fusion sealing welding process method

Abstract

The invention discloses an automatic gold-tin fusion seal welding process method, and designs an annular suction nozzle aiming at the size of a seal welding surface of a tube socket, and the annular suction nozzle can pick up the tube socket and a cover plate and provide welding pressure for the seal welding surface at the same time. And by accurately positioning the positions of the tube seat and the cover plate, high-precision alignment is realized, and the problem of cover plate alignment deflection is solved. The welding pressure is accurately controlled by a suction nozzle, the temperature is accurately controlled by a heating table in the equipment, the consistency of welding process conditions of each circuit is ensured, and the equipment cavity is filled with nitrogen with the purity being greater than 99.999%, so that on one hand, welding flux is protected from being oxidized at high temperature, and on the other hand, the welding quality is improved; on the other hand, the purpose that pure nitrogen exists in the sealed circuit is achieved, gold plating treatment is conducted on the surface of the suction nozzle, gold plating components are consistent with those on the surface of the cover plate, and a gold plating layer on the surface of the cover plate is protected against damage in the picking process.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor integrated circuit packaging, and in particular relates to an automatic gold-tin melting and welding process method. Background Art

[0002] Gold-tin sealing is one of the mainstream sealing processes for semiconductor integrated circuit ceramic packaging. It has the advantages of high airtightness, strong corrosion resistance, and few PIND problems. It is widely used in high-reliability semiconductor integrated circuits.

[0003] Gold-tin sealing is made of gold-tin (AuSn 20 ) The solder ring is used as a soldering filler metal. It undergoes melting and eutectic process at a high temperature above 300°C with the help of a certain welding pressure, thereby achieving close contact between the ceramic tube shell and the metal cover plate and completing the airtight packaging. It is an important packaging method for high-reliability semiconductor integrated circuits.

[0004] At present, the mainstream process in the industry is to pre-place gold-tin solder on the metal cover plate, and then manually use tweezers or suction pens to suck the cover plate, and align and assemble it with the tube shell base, use metal clips to fix the cover plate and the tube seat, and provide pressure for gold-tin solder welding. Finally, the assembled cover plate and the tube seat are placed in a chain or box heating device for heating and welding. The equipment cavity is filled with nitrogen atmosphere to ensure that the main component of the internal atmosphere after the circuit is sealed is nitrogen. The main problem with this process is that the manual cover plate alignment has poor accuracy, and the common cover plate deflection phenomenon will occur. The production efficiency of manual assembly is low, and the skill level of practitioners is high. At the same time, there are differences in thermal uniformity in chain or box heating equipment, circuits in different positions are heated slightly differently, and the pressure of the metal clips that provide welding pressure is also different, resulting in large fluctuations in welding quality.

[0005] With the development of science and technology and the increase in the number of tasks, the demand for semiconductor integrated circuits has also increased. At present, the industrial model has gradually changed to an automated production model. In order to improve the quality and production efficiency of product packaging, new automated production sealing process technology must be developed. Summary of the invention

[0006] The invention provides an automatic gold-tin melting and welding process method, which solves the problems of cover plate deflection and uneven heating of the circuit.

[0007] To achieve the above object, the present invention provides the following technical solutions: An automatic gold-tin sealing welding process method comprises the following steps: Place the tube sockets and cover plates of the sealing circuit in the tray in advance according to the array; Identify and mark the positions of pipe sockets and cover plates; Pick up the tube holder onto the heating table by means of a circular nozzle; Re-identify and mark the location of the tube holder; Then, the cover plate is picked up by a circular suction nozzle and placed at the center of the tube seat, and a gold-tin solder ring is preset around the cover plate; The heating table generates heat to provide welding temperature, and the suction nozzle presses the cover plate to provide welding pressure, so that the gold-tin solder melts and the circuit is sealed.

[0008] Preferably, the annular suction nozzle is designed with corresponding dimensions according to the dimensions of the sealing edge of the tube seat, and is used to suck the tube seat and the cover plate, and accurately provide welding pressure to the gold-tin sealing area.

[0009] Preferably, the annular suction nozzle is made of tungsten steel material, and a gold layer is electroplated on the surface of the annular suction nozzle.

[0010] Preferably, the material of the gold layer on the surface of the annular nozzle is the same as the material of the gold layer on the surface of the cover plate.

[0011] Preferably, the tube seat and cover plate positions are identified and marked by the image recognition system. The image recognition system identifies the tube seat position based on the grayscale comparison after the tube seat imaging to ensure that the cover plate can be placed in the center position of the tube seat when placing it.

[0012] Preferably, the image recognition system pre-saves and adjusts the contrast and grayscale parameters of the image display to ensure the accuracy of the recognition of the tube seat and the cover plate and improve the welding accuracy.

[0013] Preferably, the tube seat, the cover plate and the tray are all placed in a closed cavity, and the closed cavity is filled with nitrogen with a purity greater than 99.999%.

[0014] Preferably, during the welding process, the temperature of the heating stage is controlled within the range of 340°C ± 10°C.

[0015] Preferably, during the welding process, the pressing force of the nozzle pressing the cover plate is controlled within the range of 10N±1N.

[0016] Preferably, during the welding process, the welding time is 45s±15s.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides an automatic gold-tin melting and welding process method, and designs a ring-shaped suction nozzle according to the size of the sealing surface of the tube socket, which can pick up the tube socket and the cover plate, and provide welding pressure to the sealing surface at the same time. By accurately positioning the position of the tube socket and the cover plate, high-precision alignment is achieved, and the problem of cover plate alignment deviation is solved. The precise control of the welding pressure by the suction nozzle and the precise control of the temperature by the heating table in the equipment ensure the consistency of the welding process conditions for each circuit.

[0018] Furthermore, the device cavity is filled with nitrogen with a purity greater than 99.999%, which protects the solder from being oxidized at high temperatures on the one hand, and ensures that the inside of the circuit is filled with pure nitrogen after sealing on the other hand.

[0019] Furthermore, the surface of the nozzle is gold-plated, which has the same composition as the gold-plated surface of the cover plate, to protect the gold-plated layer on the surface of the high cover plate from damage during the picking process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The invention discloses an automatic gold-tin sealing welding process method; Figure 2 It is a schematic diagram of the tube base structure in an example of the present invention; Figure 3 is a schematic diagram of the cover plate structure in an embodiment of the present invention; Figure 4 It is a schematic diagram of the structure of the tube holder tray inside the device in an example of the present invention; Figure 5 It is a schematic diagram of the structure of the internal cover tray of the device in the example of the present invention; Figure 6 It is a bottom view of the nozzle structure in the embodiment of the present invention; Figure 7 It is a three-dimensional structural diagram of the nozzle structure in an example of the present invention; Figure 8 It is a schematic diagram of the structure of placing the tube holder on the heating platform in an example of the present invention; Fig. 9 It is a schematic diagram of the structure in which the cover plate is placed on the tube seat in an example of the present invention; Fig.10 It is a schematic diagram of the welding process of the nozzle pressing the cover plate in an example of the present invention; In the figure, 1-tube holder, 2-cover plate, 3-gold-tin solder ring, 4-tube holder tray, 5-cover plate tray, 6-suction nozzle, 7-heating table. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0024] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, the present invention provides an automatic gold-tin sealing welding process method, comprising the following steps: S101: pre-arrange the tube sockets and cover plates of the sealing circuit in a tray in an array; S102 identifies and marks the positions of the pipe base and the cover plate; S103 picks up the tube holder onto the heating table through the ring nozzle. S104 re-identifies and marks the placement position of the tube holder; S105 picks up the cover plate through the annular suction nozzle and places it at the center of the tube holder, and the cover plate is surrounded by a gold-tin solder ring; The S106 heating table generates heat to provide welding temperature, and the suction nozzle presses the cover plate to provide welding pressure, so that the gold-tin solder melts and the circuit is sealed.

[0026] The annular suction nozzle is designed with corresponding dimensions according to the dimensions of the sealing edge of the tube seat, and is used to suck the tube seat and the cover plate, and accurately provide welding pressure to the gold-tin sealing area. It can achieve the functions of sucking the tube seat, sucking the cover plate, and accurately providing welding pressure to the gold-tin sealing area.

[0027] The annular nozzle is made of tungsten steel material, and a gold layer is electroplated on the surface of the annular nozzle. The tungsten steel material is resistant to high temperature, and the gold layer material on the surface of the annular nozzle is the same as the gold layer material on the surface of the cover plate.

[0028] The positions of the tube socket and the cover are identified and marked by an image recognition system. The image recognition system identifies the position of the tube socket based on the grayscale contrast after imaging the tube socket, ensuring that the cover can be placed in the center of the tube socket.

[0029] The position of the tube socket and cover plate is identified and marked by the image recognition system, especially the position of the tube socket is identified based on the grayscale contrast after the tube socket is imaged. This feature ensures the accurate identification of the tube socket position. This helps to place the cover plate accurately in the center of the tube socket when placing it, thus avoiding poor welding or sealing problems caused by position deviation. In addition, automated identification and marking improves production efficiency and reduces errors caused by manual operation.

[0030] The image recognition system saves and adjusts the contrast and grayscale parameters of the image display in advance to ensure the accuracy of the recognition of the tube seat and the cover plate and improve the welding accuracy.

[0031] The image recognition system saves and adjusts the contrast and grayscale parameters of the image display in advance. This feature ensures the accuracy of the tube holder and cover plate recognition. By optimizing the image parameters, the system can more clearly identify the target object, thereby improving the welding accuracy. This helps to reduce errors in the welding process and improve the quality and reliability of the product.

[0032] The tube seat, the cover plate and the tray are all placed in a closed cavity, and the closed cavity is filled with nitrogen with a purity greater than 99.999%.

[0033] On the one hand, it protects the solder from being oxidized at high temperatures, and on the other hand, it achieves the purpose of ensuring that the inside of the circuit is pure nitrogen after sealing.

[0034] The temperature of the heating stage was controlled within the range of 340°C ± 10°C.

[0035] Ensures temperature stability during the soldering process. Stable temperature helps the solder to melt and solidify evenly, thus improving soldering quality. In addition, temperature control also helps reduce soldering stress caused by temperature changes and improves product reliability and stability.

[0036] The pressing force of the nozzle pressing the cover is controlled within the range of 10N±1N.

[0037] Stable pressing force helps to evenly distribute the solder and improve the sealing. In addition, it avoids poor soldering or sealing problems caused by excessive or insufficient pressing force, improving the quality and reliability of the product.

[0038] During the welding process, the welding time is 45s±15s.

[0039] Reasonable welding time helps the solder to fully melt and solidify, thus improving the welding quality. In addition, it avoids poor welding or sealing problems caused by too long or too short welding time, and improves the production efficiency and reliability of the product.

[0040] Another embodiment of the present invention provides a method for fully automatic gold-tin melting and sealing. The method designs a ring-shaped suction nozzle according to the size of the sealing surface of the tube socket, which can pick up the tube socket and the cover plate, and provide welding pressure to the sealing surface at the same time. Through the visual recognition system of the fully automatic equipment, the position of the tube socket and the cover plate is accurately positioned to achieve high-precision alignment, which solves the problem of cover plate alignment deviation. Filling the cavity of the equipment with high-purity nitrogen, on the one hand, protects the solder from oxidation at high temperatures, and on the other hand, achieves the purpose of pure nitrogen inside the circuit after sealing. The precise control of the welding pressure by the suction nozzle and the precise control of the temperature by the heating table in the equipment ensure the consistency of the welding process conditions for each circuit.

[0041] The application of the above technology improves the gold-tin sealing process technology from the existing mode to a fully automated mode, which not only improves the production efficiency of the product, but also solves the product quality problems of cover plate deflection and poor quality consistency, achieving the purpose of reducing costs and increasing efficiency, and creating more economic benefits for the enterprise.

[0042] The invention can be widely used in the field of semiconductor integrated circuit gold-tin sealing. In order to clearly explain the content of the invention, the following is a description of a specific example, which is a part of the present invention, but not all of the examples. Further, the tube shell used in this example is a CQFP100 tube socket and a matching cover plate.

[0043] Take CQFP100 housing as an example (such as Figure 2 and Figure 3 The operation of this method includes the following steps.

[0044] Step 1: Place the CQFP100 tube holder and the matching cover in the tray area inside the equipment, such as Figure 4 and Figure 5 shown.

[0045] Step 2: Adjust the contrast and grayscale parameters of the device image display to ensure the accuracy of the tube holder and cover plate recognition. After the parameter debugging is completed, it can be saved as a fixed program and can be directly called when it is packaged again later.

[0046] Step 3: Special nozzle (such as Figure 6 and Figure 7 ) Pick up the tube holder and place it on the heating table. Set the temperature of the heating table to 340℃±10℃. Figure 8 shown.

[0047] Step 4: Pick up the cover plate with a special nozzle and place it in the center of the tube holder. Fig. 9 shown.

[0048] Step 5: Use the nozzle to press the cover plate with a pressure of 10N±1N, and cooperate with the heating table to provide heating temperature to melt the gold-tin solder preset on the cover plate. The welding time is 45s±15s to achieve the brazing process between the cover plate and the tube seat. Fig.10 shown.

[0049] Step 6: Repeat steps 1 to 5 to achieve batch operation.

[0050] The fully automated process of gold-tin sealing solves the problems of cover plate deflection and poor quality consistency that are common in current industry process solutions. Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments and application fields, and the above-mentioned specific embodiments are only illustrative and instructive, rather than restrictive. Under the guidance of the specification, a person skilled in the art can also make many forms without departing from the scope of protection of the claims of the present invention, all of which belong to the scope of protection of the present invention.

Claims

1. An automatic gold-tin sealing welding process, characterized in that: The following steps are involved: Place the tube sockets and cover plates of the sealing circuit in the tray in advance according to the array; Identify and mark the positions of pipe sockets and cover plates; Pick up the tube holder onto the heating table by means of a ring-shaped suction nozzle; Re-identify and mark the location of the tube holder; Then, the cover plate is picked up by a circular suction nozzle and placed at the center of the tube seat, and a gold-tin solder ring is preset around the cover plate; The heating table generates heat to provide welding temperature, and the suction nozzle presses the cover plate to provide welding pressure, so that the gold-tin solder melts and the circuit is sealed.

2. The automatic gold-tin sealing welding process according to claim 1 is characterized in that: The annular suction nozzle is designed with corresponding dimensions according to the dimensions of the sealing edge of the tube seat, and is used to suck the tube seat and the cover plate, and accurately provide welding pressure to the gold-tin sealing area.

3. The automatic gold-tin sealing welding process according to claim 1 is characterized in that: The annular suction nozzle is made of tungsten steel material, and a gold layer is electroplated on the surface of the annular suction nozzle.

4. The automatic gold-tin sealing welding process according to claim 3 is characterized in that: The material of the gold layer on the surface of the annular suction nozzle is the same as that of the gold layer on the surface of the cover plate.

5. The automatic gold-tin sealing welding process according to claim 1 is characterized in that: The positions of the tube socket and the cover are identified and marked by an image recognition system. The image recognition system identifies the position of the tube socket based on the grayscale contrast after imaging the tube socket, ensuring that the cover can be placed in the center of the tube socket.

6. The automatic gold-tin sealing welding process according to claim 5 is characterized in that: The image recognition system saves and adjusts the contrast and grayscale parameters of the image display in advance to ensure the accuracy of the recognition of the tube seat and the cover plate and improve the welding accuracy.

7. The automatic gold-tin sealing welding process according to claim 1 is characterized in that: The tube seat, the cover plate and the tray are all placed in a closed cavity, and the closed cavity is filled with nitrogen with a purity greater than 99.999%.

8. The automatic gold-tin sealing welding process according to claim 1 is characterized in that: During the welding process, the temperature of the heating table is controlled within the range of 340℃±10℃.

9. The automatic gold-tin sealing welding process according to claim 1, characterized in that: During the welding process, the pressing force of the nozzle on the cover plate is controlled within the range of 10N±1N.

10. The automatic gold-tin sealing welding process according to claim 1, characterized in that: During the welding process, the welding time is 45s±15s.

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