Cover plate positioning tool for fusion-sealed circuit and assembling method of cover plate positioning tool

Abstract

The invention belongs to the technical field of semiconductor integrated circuit packaging, and particularly relates to a cover plate positioning tool for a fusion-sealed circuit and an assembling method of the cover plate positioning tool. Tungsten copper is adopted as a core material of the positioning tool, and the high hardness and the high thermal conductivity of the tungsten copper ensure that the tool can be normally used at the high temperature of 300-350 DEG C; the cover plate and the tube shell are effectively limited by the positioning column, and the bevel angle structure on the positioning column provides enough space for overflowing of the welding flux on the side edge of the cover plate; according to the tool, the process of manually assembling the cover plate by using tweezers is replaced, a cavity of a circuit faces downwards in the whole packaging process, the problems that the cover plate is scratched by the tweezers and wires are touched by mistakenly entering the cavity are solved, pollution and damage to the interior of the cavity caused by external factors are also isolated, and the tool plays a crucial role in prevention and control of external redundant objects; the pressure applying face, making contact with the surface of the cover plate, of the tool only covers the sealing welding face area of the tube shell, it is guaranteed that welding flux is evenly stressed in the heat sealing process, the problems of cover plate indentation and rubbing marks caused by a clamp are reduced, and the packaging consistency of products is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor integrated circuit packaging, and in particular relates to a cover plate positioning tool for a fusion-sealed circuit and an assembly method thereof. Background Art

[0002] With the rapid development of the electronics industry in the fields of weapons, aviation and aerospace, semiconductor integrated circuit packaging technology, as a key link in the electronics industry, has increasingly higher requirements for the reliability of electronic components. The working environment faced by electronic components is becoming more and more complex and harsh, so the requirements for their reliability have reached an unprecedented level. As the last key process in the assembly and production of semiconductor circuits, the importance of airtight packaging is self-evident. In order to isolate the chip from the external environment, limit the water vapor content in the cavity, and avoid the intrusion of external gases, airtight packaging becomes particularly important as the last process in the assembly and production of semiconductor circuits. As a type of airtight packaging for military semiconductor integrated circuits, gold-tin melting sealing is mainly in the form of a ceramic tube shell plus a gold-plated Kovar alloy cover plate, and then a gold-tin alloy is used as a brazing solder. At a high temperature of more than 300°C, with the help of a certain welding pressure, and in the protection of an inert atmosphere, the tube shell and the cover plate are in close contact and the airtight packaging is completed.

[0003] The current gold-tin sealing process mainly uses two methods to assemble the circuit, one is to clamp the circuit with a fixture or to invert the tooling. Both methods have some hard problems that are difficult to overcome, resulting in the yield rate and production efficiency being lower than other packaging processes. Among them, the single fixture clamping method has problems such as manual alignment of the cover plate offset, uneven force position of the fixture, and the introduction of excess materials when the cavity is facing upward when assembling the cover plate. Figure 1 (a) and Figure 1 As shown in (b), the problems existing in the single fixture clamping method lead to a decrease in the qualified rate and production efficiency of the sealing circuit; the sealing inverted tooling is a three-layer structure of the base, circuit, and pressure plate, and the circuit is wrapped in the middle layer. This method has problems such as the mold preventing the solder from overflowing, low heat transfer efficiency, and uneven heat and force on the circuit. Figure 1 As shown in (c) and (d), the problems existing in the inverted sealing tooling have greatly affected the quality of the sealing cap. Both of the above-mentioned gold-tin sealing packaging methods have hard problems that cannot be improved by some processes, making the gold-tin sealing process lower than other packaging processes in terms of yield and production efficiency. In order to solve the problems of low production efficiency of the sealing circuit, large cover plate offset, poor solder overflow and excess materials, it is necessary to start from the assembly process of the cover plate and optimize and improve it. Summary of the invention

[0004] The present invention provides a cover plate positioning tool for a sealing circuit and an assembly method thereof, so as to solve the technical problems of low production efficiency of the sealing circuit, large cover plate deviation, poor solder overflow and excess materials existing in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: A cover plate positioning tool for a sealing circuit comprises a rectangular frame, positioning columns are arranged on the four sides of the rectangular frame, the rectangular frame positioning columns constitute the positioning tool, the cover plate is fixed above the rectangular frame, and a tube shell is placed above the cover plate.

[0006] The connection between the positioning column and the rectangular frame is designed as an oblique angle structure.

[0007] The positioning column and the rectangular frame are both made of tungsten copper.

[0008] The shape and size of the rectangular frame are 0.05mm larger than the single side length of the cover plate.

[0009] An assembly method for a cover plate positioning tool for a sealing circuit, the assembly method comprising the following steps: Step 1: Place the positioning tool steadily on the table with the four positioning posts facing upwards; Step 2: Place the cover plate on the upper surface of the rectangular frame, and use the four positioning columns to limit the four sides of the cover plate; Step 3: Fix the tube shell on the cover plate, and use a clamping tool to clamp the tube shell and the cover plate; Step 4: Repeat steps 1 to 3 above to complete the circuit assembly one by one.

[0010] The cover is placed with the side with the solder ring facing up.

[0011] When the tube shell is placed, the cavity of the tube shell faces downward, and the sealing welding surface of the tube shell corresponds to the solder ring of the cover plate.

[0012] When placing the tube shell and cover plate, a vacuum suction pen is used.

[0013] When the clamping tool described in step three is clamping, the clamping surface on one side of the clamping tool is attached to the bottom ceramic of the tube shell, and the clamping surface on the other side of the clamping tool is attached to the bottom of the positioning tool.

[0014] The positioning tooling can change the structural dimensions according to different types of circuit boards.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a cover plate positioning fixture for a sealing circuit. Positioning posts are arranged on the four sides of a rectangular frame to form a positioning fixture, which provides a precise placement position for the cover plate, avoids the offset problem during the traditional manual alignment of the cover plate, and makes the relative position of the cover plate and the tube shell more accurate, effectively improving the assembly accuracy of the sealing circuit and ensuring product quality. The positioning fixture of the present invention provides a stable and standardized cover plate placement platform, which only requires the placement of the cover plate and the tube shell, simplifying the assembly operation process of the cover plate and the tube shell. The operator only needs to place the cover plate on the rectangular frame, and then place the tube shell. Compared with the previous complicated manual alignment operation, the operation difficulty is significantly reduced and the production efficiency is improved.

[0016] Furthermore, the angled structural design at the connection between the positioning column and the rectangular frame cleverly provides overflow space for the solder during the sealing process. This avoids the problem of the solder not being able to overflow normally due to structural obstructions, thereby affecting the quality of the sealing, and ensures the integrity and reliability of the sealing. During the sealing process, when the solder is heated and flows, the rectangular frame that matches the size of the sealing surface of the tube shell can make the stress distribution on the solder more uniform, avoiding the stress concentration problem caused by uneven force in traditional fixtures. The positioning column only serves to limit the position but not to bear force, avoiding the possibility of cracks or other structural damage at the connection with the frame, which may cause tooling failure, extend the service life of the tooling, and reduce production costs.

[0017] Furthermore, the positioning column and the rectangular frame are both made of tungsten copper material, which has excellent high temperature resistance and can maintain stable physical and chemical properties in the high temperature environment required for sealing (such as 300-350℃), with small deformation and corrosion resistance, ensuring the reliability of the tooling during high temperature sealing and the consistency and high quality of each sealing operation. Tungsten copper material has high hardness and good wear resistance. During frequent assembly and use, it can effectively resist the friction and collision of the cover plate, tube shell and other possible contact objects, reduce the wear of the tooling surface, maintain the accuracy of the tooling for a long time, reduce the product defect rate caused by tooling wear, and improve production efficiency. Its good thermal conductivity helps to transfer heat quickly and evenly during sealing, so that the entire tooling, cover plate and tube shell can be heated evenly. This is not only conducive to the melting and flow of solder, ensuring the sealing effect, but also avoids the thermal stress caused by local overheating or overcooling from damaging the product, further improving product quality and stability.

[0018] Furthermore, the shape and size of the rectangular frame are similar to those of the cover plate, ensuring the perfect fit of the cover plate on the positioning tooling, further improving the accuracy and stability of the cover plate positioning. During the assembly process, the effective positioning of the cover plate by the positioning column prevents the cover plate from shaking, shifting, and other unstable conditions, further making the subsequent placement of the tube shell more accurate, laying a solid foundation for high-quality sealing. The similar shape and size of the cover plate and the rectangular frame make the pressure more evenly distributed on the cover plate solder. When the fixture applies pressure to the tube shell and the cover plate, due to the close fit of the rectangular frame and the cover plate, the pressure can be evenly transmitted to the entire sealing surface area of ​​the tube shell, avoiding the problem of anisotropy of solder flow caused by uneven force, and ensuring the consistency and reliability of the product after sealing.

[0019] Furthermore, the present invention discloses an assembly method for a cover plate positioning tool for a fusion-sealed circuit, including steps such as placement of the positioning tool, the order of placement of the cover plate and the tube shell, and the use of the fixture, forming a set of standardized operating procedures. Operators only need to follow the process to achieve efficient and accurate assembly, reduce the impact of human factors on the assembly quality, and improve the mass production capacity and quality stability of the product. By repeatedly executing standardized steps one to three, the assembly of the circuit can be completed one by one quickly and orderly. Compared with the traditional non-standardized assembly method, the time for exploration and adjustment during the operation is reduced, the assembly speed is greatly improved, the needs of large-scale production are met, and the production cost is also reduced.

[0020] Furthermore, the cover plate is placed with the solder ring facing upwards, so that the solder can be melted smoothly under the action of gravity and high temperature and flow downward from the sealing surface to form a "meniscus" with the side of the cover plate, achieving a good welding effect. When the cover plate is located below the tube shell, it can effectively prevent the solder from flowing into the tube shell cavity and causing contamination and short circuit problems of the chip or bonding wire, effectively protecting the circuit function from damage and ensuring the reliability of the melting and sealing process.

[0021] Furthermore, the sealing surface of the tube shell faces downward and corresponds to the solder ring of the cover plate, thereby achieving precise alignment of the sealing surface and the solder. During the sealing process, the high temperature melts the solder and fills it between the sealing surface of the tube shell and the cover plate, ensuring the firmness and sealing of the welding, effectively preventing external gases, water vapor, etc. from invading the interior of the circuit, and improving the airtightness and reliability of the product. In addition, this assembly method makes the circuit cavity face downward throughout the entire sealing process, isolating it from pollution and damage caused by external factors, and plays a vital role in the prevention and control of foreign excess objects. This placement method makes the heat transfer during the sealing process more direct and efficient, which is conducive to the rapid melting and uniform flow of the solder, and promotes the smooth diffusion of the solder. At the same time, it also reduces the secondary sealing assembly operations that may be required due to inaccurate alignment of the sealing surface and the solder, further improving production efficiency.

[0022] Furthermore, the use of a vacuum suction pen to place the tube shell and cover plate avoids the problem of scratches on the cover plate caused by the tweezers gripping process, and eliminates the risk of tweezers mistakenly entering the circuit cavity and causing wire contact. Whether it is the tube shell or the cover plate, tiny scratches on their surfaces may affect the performance and appearance quality of the product. The vacuum suction pen gently operates the tube shell and cover plate through a non-contact adsorption method, effectively protecting their surface integrity and corrosion resistance, and improving product quality. The vacuum suction pen can provide precise adsorption and placement control, and the operator can more accurately place the cover plate in the specified position on the positioning tooling, as well as place the tube shell on the cover plate. Compared with the cover plate falling off or position deviation that may occur when gripping with tweezers, the vacuum suction pen further improves the accuracy of assembly, which helps to improve product quality and production efficiency.

[0023] Furthermore, one side of the plane of the fixture clamps the ceramic at the bottom of the tube shell, and the other side clamps the bottom of the positioning tool. This clamping method can ensure that pressure is evenly applied to the sealing surface of the tube shell. During the sealing process, uniform pressure helps the solder to flow evenly on the sealing surface to form a uniform and firm weld, improve the quality of the sealing, and avoid welding defects caused by uneven pressure, such as voids, air leaks and other problems. Through a reasonable clamping position, the fixture can firmly fix the tube shell, cover plate and positioning tool together to form a stable overall structure. During the sealing process, the relative movement between components is avoided to affect the sealing effect, ensuring the stability and reliability of the sealing process, which is conducive to improving the consistency and quality stability of the product.

[0024] Furthermore, the positioning fixture composed of the rectangular frame and the positioning column can be customized with different structural dimensions according to different types of circuits, realizing targeted force for different products. By changing the structural dimensions of the fixture, it can be ensured that each type of circuit board can obtain the best cover positioning effect. Whether it is a large or small circuit board, the fixture can provide precise positioning and stable support, ensuring the high quality of different types of products during the sealing process. Meet diverse market needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 : Schematic diagram of the analysis of the technical problems existing in the single fixture clamping method and the inverted sealing tooling; Figure 2 : Schematic diagram of the top view of the positioning tooling; Figure 3 : Side view of the positioning tooling; Figure 4 : Stereoscopic image of positioning tooling; Figure 5 : Schematic diagram of positioning column limit; Figure 6 : Schematic diagram of angled structure design; Figure 7: Schematic diagram of tube shell placement; Figure 8 : Schematic diagram of clamping force between cover plate and tube shell; Fig. 9 : Schematic diagram of the assembly process of a single sealing circuit; Fig.10 : Schematic diagram of the assembly process of all sealing circuits.

[0026] Explanation of reference numerals: 1. rectangular frame; 2. positioning column; 3. cover plate; 4. tube shell; 5. positioning tooling. DETAILED DESCRIPTION

[0027] In order to further understand the content of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.

[0028] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0029] See also Figures 2 to 10 , which are the top view, side view and stereogram of the positioning fixture structure in the present invention and the schematic diagram of each design structure detail. The positioning fixture 5 is composed of a rectangular frame 1 and a positioning column 2. The positioning column 2 is fixed to the outer side walls of the four sides of the rectangular frame 1. At the connection between the positioning column 2 and the rectangular frame 1, there is a Figure 5 The angled structural design shown in ; Fig. 9 and Fig.10 It is an assembly flow chart of the present invention, such as Fig. 9 As shown in the assembly process, during assembly, when the positioning fixture 5 composed of the rectangular frame 1 and the positioning column 2 is placed flat, the positioning column 2 should face upward; the cover plate 3 is placed above the rectangular frame 1, and the positioning column 2 plays a role of limiting the cover plate 3, as shown in FIG. Figure 5 As shown in the figure; the gray part on the cover plate 3 is the solder ring of the cover plate 3; the tube shell 4 is fixed on the upper surface of the cover plate 3 with the back facing upwards; after the cover plate 3 and the tube shell 4 are installed on the positioning fixture 5, they are clamped and fixed with a clamping tool, one clamping surface of the clamping tool clamps the bottom ceramic of the tube shell 4, and the other clamping surface of the clamping tool clamps the bottom of the positioning fixture 5. The assembly is completed, the structure is symmetrical, and the stress-bearing parts are uniform, as shown in the figure. Figure 8 As shown in . Complete the circuit assembly one by one in the same assembly method, such as Fig.10 shown.

[0030] This embodiment provides an assembly method for a cover plate positioning tool for a sealing circuit, and the specific assembly method is as follows: In the field of semiconductor integrated circuit packaging, the packaging quality of the melt-sealed circuit is of vital importance. The traditional melt-sealing process has many problems in the assembly process of the cover plate and the tube shell, such as the manual alignment of the cover plate is easy to offset, the clamp force is uneven, and the assembly process is easy to introduce excess materials, etc. These problems seriously affect the qualification rate and production efficiency of the melt-sealed circuit. The present embodiment aims to solve these problems by adopting a new type of cover plate positioning tool and assembly method for the melt-sealed circuit to improve the packaging quality and production efficiency of the melt-sealed circuit. The present embodiment provides a cover plate positioning tool and assembly method for the melt-sealed circuit. The tube shell 4 used in this example is the QF0606-10 flat ceramic shell packaging form FCP10, the cover plate 3 is the matching MA06090609A gold-plated Kovar alloy, and the base material of the positioning tool 5 is tungsten copper. The specific implementation method is as follows: Select appropriate tungsten copper material to make the rectangular frame 1 and the positioning column 2, and firmly install the processed positioning column 2 on the rectangular frame 1 to form the positioning fixture 5. Design and process the size of the rectangular frame 1 and the positioning column 2 according to the size of the cover plate 3, so that the shape and size of the rectangular frame 1 are 0.5mm larger than the shape and size of the cover plate 3 to be packaged on one side, and ensure that the two are exactly the same to ensure the subsequent limit accuracy. The connection between the positioning column 2 and the rectangular frame 1 adopts an angled structure design, such as Figure 6 As shown in , the height of the positioning column 2 should ensure that it can effectively limit the movement of the cover plate 3, thereby effectively limiting the movement of the tube shell 4. The processed positioning column 2 is firmly installed on the rectangular frame 1 to form a positioning tool 5.

[0031] Place the positioning tool 5 steadily on a clean, flat table, and ensure that the four positioning posts 2 on the rectangular frame 1 are all facing upward. Use a vacuum suction pen to suck up the cover plate 3. When sucking, the vacuum suction pen adsorbs the inner side of the cover plate 3 with the solder ring, and places the cover plate 3 with the solder ring facing upward on the upper surface of the rectangular frame 1. At this time, the four positioning posts 2 will automatically and accurately limit the four sides of the cover plate 3 to prevent the cover plate 3 from shifting during the placement process and subsequent operations, and limit the relative movement between the cover plate 3 and the tube shell 4 in subsequent operations. Similarly, use a vacuum suction pen to suck up the tube shell 4. When sucking, the vacuum suction pen adsorbs the bottom ceramic of the tube shell 4, and the sealing surface of the tube shell 4 faces downward, that is, the circuit cavity of the tube shell 4 faces downward, so that the sealing surface of the tube shell 4 accurately corresponds to the solder ring of the cover plate 3, and then the tube shell 4 is placed on the cover plate 3. During the entire packaging process of the circuit, the circuit cavity of the tube shell 4 is facing downward and placed upside down, isolating it from pollution and damage caused by external factors, and plays a vital role in the prevention and control of foreign superfluous objects. During the assembly process of the cover plate 3 and the tube shell 4, a vacuum suction pen is used for adsorption assembly, replacing the manual assembly process using tweezers, avoiding the situation where the cover plate 3 and the tube shell 4 are scratched when the tweezers are clamped, and at the same time, avoiding the risk of tweezers accidentally entering the circuit cavity of the tube shell 4 and causing wire contact.

[0032] After the assembly is completed, select a suitable clamp and fit one side of the clamping tool to the bottom ceramic of the tube shell 4 to ensure that the clamp is in full contact with the tube shell 4, and the other side of the clamping tool is fitted to the bottom of the positioning tool 5; during the clamping process, ensure that the tube shell 4 and the cover plate 3 are tightly fixed; the application surface of the positioning tool 5 will only cover the sealing surface area of ​​the tube shell 4, ensuring that the solder is uniformly stressed during subsequent sealing, avoiding the problem of anisotropy of solder flow caused by differences in pressure size and action points, and improving the consistency of circuit products, such as Figure 8 The solder ring of the cover plate 3 melts during the sealing process and overflows from the sealing surface of the tube shell 4. The special bevel structure design between the positioning column 2 and the rectangular frame 1 provides sufficient overflow space for the overflowed solder, avoiding the situation of hindering the flow of the solder.

[0033] Repeat the above assembly steps to complete the assembly of the circuit one by one. Since the assembly of the positioning tool 5 of the present invention only requires the placement of the cover plate 3 and the tube shell 4, and the positioning column 2 is used to limit the cover plate 3 and the tube shell 4, manual alignment assembly is not required, which effectively improves the assembly and packaging rate of the positioning tool and the circuit of the present invention.

[0034] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A cover plate positioning tool for a sealing circuit, characterized in that: It comprises a rectangular frame (1), positioning columns (2) are arranged on four sides of the rectangular frame (1), the rectangular frame (1) and the positioning columns (2) form a positioning tool (5), a cover plate (3) is fixed above the rectangular frame (1), and a tube shell (4) is placed above the cover plate (3).

2. A cover plate positioning tool for sealing circuit according to claim 1, characterized in that: The connection between the positioning column (2) and the rectangular frame (1) is designed as an oblique angle structure.

3. A cover plate positioning tool for sealing circuit according to claim 2, characterized in that: The positioning column (2) and the rectangular frame (1) are both made of tungsten copper material.

4. The cover plate positioning tool for sealing circuit according to claim 1, characterized in that: The shape and size of the rectangular frame (1) are 0.05 mm larger than the single side length of the cover plate (3).

5. An assembly method for a cover plate positioning tool for a sealing circuit, based on the cover plate positioning tool for a sealing circuit as claimed in any one of claims 1 to 4, characterized in that: The assembly method includes the following steps: Step 1: Place the positioning tool (5) steadily on the table with the four positioning posts (2) facing upwards; Step 2: placing the cover plate (3) on the upper surface of the rectangular frame (1), and using the bases of the four positioning columns (2) to limit the four sides of the cover plate (3); Step 3: Fix the tube shell (4) on the cover plate, and use a clamping tool to clamp the tube shell (4) and the cover plate (3); Step 4: Repeat steps 1 to 3 above to complete the circuit assembly one by one.

6. The assembly method of the cover plate positioning tool for the sealing circuit according to claim 5, characterized in that: When the cover plate (3) is placed, the side with the solder ring is placed upwards.

7. The assembly method of the cover plate positioning tool for the sealing circuit according to claim 6, characterized in that: When the tube shell (4) is placed, the cavity of the tube shell (4) faces downwards, and the sealing welding surface of the tube shell (4) corresponds to the solder ring of the cover plate (3).

8. The assembly method of the cover plate positioning tool for the sealing circuit according to claim 7, characterized in that: When the tube shell (4) and the cover plate (3) are placed, a vacuum suction pen is used.

9. The assembly method of the cover plate positioning tool for the sealing circuit according to claim 5, characterized in that: When the clamping tool described in step three is clamping, the clamping surface on one side of the clamping tool is in contact with the bottom ceramic of the tube shell (4), and the clamping surface on the other side of the clamping tool is in contact with the bottom of the positioning tool (5).

10. According to the method for assembling a cover plate positioning tool for a sealing circuit as claimed in claim 5, the positioning tool (5) can change the structural dimensions according to different types of circuit boards.

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