Multipoint material injection packaging mold of transistor semiconductor

Abstract

The invention relates to the technical field of molds, in particular to a transistor semiconductor multi-point injection packaging mold which comprises upper molds, lower molds, a driving assembly, a slow flow plate and an injection control rod, the upper molds and the lower molds form cavities when closed, a plurality of injection ports are formed in the upper molds, every two adjacent upper mold cavities are communicated through the corresponding injection ports, and the upper mold cavities and the lower mold cavities are communicated through the corresponding injection ports. The flow slowing plate is slidably mounted in the upper mold, the material injection control rod is slidably mounted in the material injection opening, the interior of the material injection control rod communicates with the mold material injection pipe, and the driving assembly controls the flow slowing plate and the material injection control rod to move. When the liquid packaging material is pressurized and injected, the flow slowing plate is used for blocking and slowing down the impact speed of the liquid packaging material, the impact force borne by the connecting gold wire is reduced, wire collapse or stripping of the connecting gold wire is avoided, and the use safety and stability of a product are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of mold technology, specifically to a multi-point injection packaging mold for transistor semiconductors. Background Technology

[0002] A transistor is a single component based on semiconductor materials and is the basic building block of modern electronic circuits. Due to their fast response speed and high accuracy, transistors can be used for various digital and analog functions, such as amplification, voltage regulation, switching, and signal modulation. Transistors are commonly used in the production of diodes, triodes, field-effect transistors, and thyristors. In the manufacturing process of transistors, the molding process is an indispensable and crucial step. During molding, multiple mounted and interconnected transistor semiconductor frames are placed in a mold. Preheated plastic material is injected into multiple mold cavities through multi-point injection. The molding compound rapidly solidifies within the mold, reaching a certain hardness after pressure holding. The molding compound then encapsulates the transistor semiconductor, resulting in a finished product. Molded products are designed to completely encapsulate lead frames, transistors and devices, and gold wires. This process directly affects the product's function, appearance, and reliability, aiming to facilitate use. The encapsulant also protects the chip. Finally, the excess material is removed from the molded product to obtain a complete product. However, the encapsulated transistors and semiconductors are of various types and heights, resulting in a thicker finished product. The mismatch in thermal expansion coefficients between the transistors / devices and the molding compound creates localized thermal stress, causing warping in the molded product. Excessive warping not only increases the difficulty of transistor manufacturing processes such as ball-mounting, cutting, and surface mounting after molding, but also significantly increases the process defect rate during chip assembly and can easily lead to serious device failures.

[0003] To avoid product warping due to localized thermal stress after transistor semiconductor molding, patent application CN202111372272.0 provides a chip molding mold and its secondary molding process. This invention uses an upper mold, a lower mold, an injection molding assembly, and a liftable mold protrusion. When the mold protrusion descends, it protrudes downwards relative to the upper mold. The injection molding assembly includes an injection tube, an injection control block, and a connecting tube. The injection tube is embedded in the upper mold, and an injection groove is provided within its wall. The connecting tube communicates with the injection groove, and the inner wall of the injection tube has an injection groove opening. The injection control block can open or close the injection groove opening. The protruding mold protrusion forms a first molding layer with grooves on the surface of the molded product. Cooling and curing releases stress to alleviate warping. The grooves are then filled to form a flat second molding layer, completing the product molding. However, during pressurized injection molding, the flow and impact of the liquid encapsulant may cause gold wire misalignment. Excessive gold wire misalignment can lead to wire collapse or peeling, causing short circuits or open circuits in the device.

[0004] Therefore, in order to avoid defects such as mold warping and gold wire misalignment during the packaging process of transistor semiconductors, a multi-point injection packaging mold for transistor semiconductors is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-point injection molding die for transistor semiconductors. To avoid localized thermal stress during the molding process that could cause warping of the encapsulated product, a buffer plate is placed inside the upper die to perform two injection molding processes on the transistor semiconductor. During the first injection, the buffer plate cushions the liquid encapsulant, preventing gold wire displacement, collapse, or peeling. After the injection cools, a first encapsulant layer with grooves is formed on the transistor semiconductor. These grooves release stress and alleviate warping deformation. After the buffer plate is returned to the upper die, a second injection is performed, filling the grooves to form a complete encapsulant layer, preventing gas oxidation of the internal gold wires, and ensuring product safety and stability.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A multi-point injection molding die for transistor semiconductors includes an upper die, a lower die, a driving assembly, a flow buffer, and an injection control rod. The upper die has multiple identical upper cavities, and the lower die has multiple lower cavities corresponding to the upper cavities. When the upper and lower cavities are closed, they form a mold cavity. A cooling water channel is provided inside the upper die for cooling during injection. Multiple injection ports are located between two adjacent upper cavities, connecting them. The flow buffer is slidably installed inside the upper die and can be limited within the upper cavity, with its sidewall located on one side of the injection port. The injection control rod is slidably installed inside the injection port. The driving assembly is fixedly installed above the upper die and controls the movement of the flow buffer and the injection control rod, causing the flow buffer to shield the gold wires facing both sides of the injection port.

[0008] First, a transistor semiconductor wafer is placed inside the lower mold, with both ends of the wafer secured within the lower mold cavity. When the upper and lower molds are closed, the semiconductor wafer is positioned within the cavity. The injection tube passes through the injection control rod, and molten liquid encapsulant is pressurized and injected into the injection port from the bottom of the control rod. The injection port connects to two identical mold cavities on either side, allowing the liquid encapsulant to flow into both cavities. Before injection begins, the drive assembly controls a flow buffer to move vertically downwards, changing its position from flush with the top of the upper mold cavity to having its bottom extending deep into the upper mold cavity. During the initial injection, the liquid encapsulant first contacts the sidewall of the buffer plate when it enters the mold cavity, then gradually wraps around the connecting wires. Finally, the liquid encapsulant fills the mold cavity and waits for it to solidify inside the mold. After holding the pressure, it reaches a certain hardness, completing the first encapsulation of the transistor semiconductor wafer. The buffer plate is used to block and slow down the impact speed of the liquid encapsulant during pressurized injection, reducing the impact force on the connecting wires and preventing the connecting wires from shifting, collapsing, or peeling due to the impact of the liquid encapsulant, which could cause short circuits or open circuits, thus preventing circuit failure and a decrease in the reliability of the transistor semiconductor.

[0009] Preferably, the upper mold has multiple square grooves inside, the flow buffer moves within the square grooves, the flow buffer is set in a "U" shape, the connecting gold wire is surrounded inside the flow buffer by the side walls at both ends of the flow buffer, and the flow buffer side plate is provided with uniform openings.

[0010] By setting the flow buffer in a "U" shape, with the U-shaped opening facing downwards and the connecting gold wire located inside the U-shaped opening, the flow buffer can protect the connecting gold wire from the impact of the flowing liquid encapsulant. The drive assembly controls the up and down movement of the flow buffer and the injection control rod. During the first injection, the sidewall of the flow buffer is located inside the mold cavity, and the bottom of the injection control rod is located in the middle of the injection port. After the first injection is completed and the liquid encapsulant solidifies in the mold, a first sealing layer is formed on the surface of the transistor semiconductor wafer. The groove shape on the sealing layer is the same as the groove shape on the sidewall of the flow buffer. At this time, the drive assembly controls the flow buffer and the injection control rod to move upwards, with the bottom of the flow buffer... The bottom of the injection control lever is flush with the top of the upper mold cavity. Liquid encapsulant then flows out from the injection control lever, filling the grooves of the first encapsulation layer and the empty parts of the mold cavity. The liquid encapsulant then waits for the liquid encapsulant to solidify in the mold, forming a flat second encapsulation layer. There are many types of materials on the transistor semiconductor wafer, and their heights vary. Therefore, the product is relatively thick after the first encapsulation. Due to the mismatch of the thermal expansion coefficients of different materials on the transistor semiconductor, local thermal stress is generated. Thermal stress can cause the product to warp. The multiple grooves on the first encapsulation layer can release stress on the transistor semiconductor and alleviate warping, preventing the transistor semiconductor from warping too much after injection encapsulation.

[0011] Preferably, the upper mold cavity has a baffle movable groove, which is connected to the injection port. Two identical injection baffles are fixedly installed on both sides of the injection control rod. The bottom of the injection baffle is flush with the bottom of the injection control rod. The injection baffle is slidably installed in the baffle movable groove. The injection baffle passes through both ends of the flow buffer and is located above the connecting gold line. During the first injection, the injection baffle is located in the middle of the injection port, and during the second injection, the injection baffle is located at the top of the injection port.

[0012] By setting an injection baffle inside the upper mold and sliding it with the baffle's movable groove, the injection baffle is shaped like a rectangular thin plate connecting two identical square plates. When the injection control rod injects material for the first time, the bottom of the injection baffle is horizontally positioned at the center of the injection port along with the bottom of the injection control rod, and the bottom of the injection baffle is below the baffle's movable groove. After the first material seal is formed, when the drive assembly controls the injection control rod to move upward, the injection baffle moves upward with the injection control rod, and the injection baffle is located inside the baffle's movable groove, with the bottom of the injection baffle flush with the top of the baffle's movable groove. At this time, the first material seal is formed. The first-layer sealing layer has grooves shaped like injection baffles, which improves the stress release effect of transistor semiconductors and alleviates warping. The injection baffles reserve injection space for the second injection. After the first injection is completed, the injection control rod and the injection baffle move upward, leaving remaining space so that the second sealing layer can be formed flat. The complete product sealing protects the transistor semiconductor chip structure from damage, prevents gas oxidation of the internal connecting gold wires, and ensures the safety and stability of the product. Moreover, no additional injection port is required for the second injection, avoiding the possibility of multiple injection ports causing air to enter the mold and affect the injection molding effect.

[0013] Preferably, the two side walls of the flow-retardant plate are configured as a fence shape consisting of multiple fence posts, and the edges of the multiple fence posts are provided with rounded corners.

[0014] By setting the sidewalls of the flow buffer to a fence shape, the liquid encapsulant flows through the gaps between the fence posts before wrapping the connecting gold wires and the surface of the transistor semiconductor wafer. The liquid encapsulant can fully wrap the transistor semiconductor wafer through the fence sidewalls, preventing air from causing incomplete injection molding. The rounded corners make the flow of the liquid encapsulant more concentrated and gentle. According to Bernoulli's principle, at any cross-section of the same flow tube, the sum of the kinetic energy, potential energy, and pressure potential energy of a unit volume of fluid is a constant. When the liquid encapsulant flows through the flow buffer, it can adhere more evenly to the transistor semiconductor wafer, avoiding missing encapsulant in certain areas and improving the effect of multi-point injection.

[0015] Preferably, the flow-retarding plate is symmetrically provided with arc-shaped plates, which are located on the fence posts on both sides. The arc surface of the arc-shaped plates faces the injection port, and the distance between the two arc-shaped plates is greater than the width of the injection port.

[0016] By setting an arc-shaped plate on the flow buffer, when the liquid encapsulant flows from the injection port to the mold cavity, the liquid encapsulant that needs to flow through the flow buffer will first contact the arc-shaped plate and flow from the arc surface of the arc-shaped plate to the gap between the grid posts, which reduces the flow impact of the liquid encapsulant and makes the flow of the liquid encapsulant smoother, further preventing the gold wire from collapsing or peeling.

[0017] Preferably, the upper mold has a connecting groove inside, the connecting groove is located above the square groove, and a connecting frame is slidably installed in the connecting groove. The bottom of the connecting frame connects the ends of the injection baffles on both sides of the injection control rod.

[0018] By setting a connecting frame inside the upper mold, when the injection control rod moves upward, it applies an upward pulling force to the end of the injection baffle. When the injection baffle moves upward to demold, it is subject to the adhesion force of the encapsulating material and the uneven pulling force of the injection control rod, which may cause the injection baffle to tilt during demolding, causing deformation or damage to the first material seal layer. The simultaneous movement of the connecting frame and the injection control rod ensures that the injection baffle is subjected to a uniform upward pulling force, ensuring smooth and complete demolding and improving the demolding effect.

[0019] Preferably, the injection baffle and the connecting frame are both hollow, the injection baffle and the connecting frame are internally connected, the injection baffles on both sides of the injection control rod are connected, and the cold water channel is internally connected to the connecting frame.

[0020] By connecting the injection baffle to the cold water channel, cooling water flows into the injection baffle through the cold water channel and circulates continuously each time the injection control lever injects and encapsulates the material. At this time, the injection baffle enhances the cooling effect on the encapsulating material, accelerating its solidification. The encapsulating material shrinks during cooling, and uneven cooling can lead to internal stress concentration. The cooling effect of the injection baffle can reduce internal stress and improve the service life of transistor semiconductors. During the injection process, the cold water can support the injection baffle, preventing deformation of the injection baffle when the liquid encapsulating material solidifies and applies stress. This also prevents gaps between the injection baffle and the upper mold, ensuring the sealing effect of the mold cavity.

[0021] Preferably, the sidewall of the baffle movable groove is made of shape memory metal material, and the sidewall of the baffle movable groove expands and deforms when the set temperature is reached.

[0022] By using a baffle movable groove made of shape memory metal material and setting the temperature to 60℃, when the liquid encapsulant, heated to a molten state, flows into the injection port, the baffle movable groove expands and deforms, increasing the adhesion between the baffle movable groove and the injection baffle, thereby increasing the sealing effect inside the upper mold cavity, preventing the entry of external gas and preventing the liquid encapsulant from flowing into the gap between the upper mold and the injection baffle. At the same time, it can reduce wear when the injection baffle resets, improving the injection and encapsulation effect of the mold.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. By setting a flow buffer in the upper mold, the flow buffer is used to block and slow down the impact speed of the liquid encapsulant when it is injected under pressure. This reduces the impact force on the connecting gold wires and prevents the connecting gold wires from shifting, collapsing, or peeling due to the impact of the liquid encapsulant, which could cause short circuits or open circuits. This prevents circuit failure and reduces the reliability of transistor semiconductors, thereby improving the service life of transistor semiconductors.

[0025] 2. By moving the flow plate, multiple uniform grooves are formed on the first material sealing layer, which can release stress on the transistor semiconductor and alleviate warping. This prevents the transistor semiconductor from warping too much after injection packaging, and prevents the packaging process from becoming more difficult, such as balling, cutting, and surface mounting. This reduces the defect rate of the production process and improves the reliability of the transistor semiconductor.

[0026] 3. By setting an injection baffle below the flow plate, after the first injection is completed, the injection control rod and the injection baffle move upward, leaving remaining space to allow the second material seal layer to form smoothly. Moreover, no additional injection port is needed for the second injection. The original injection port is used to avoid the presence of multiple injection ports, which would cause air to enter the mold and affect the injection molding effect. The complete product material seal protects the transistor semiconductor chip structure from damage, prevents gas oxidation of the internal connecting gold wires, and ensures the safety and stability of the product. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the external structure of the present invention;

[0028] Figure 2 This is a schematic diagram of the lower mold structure of the present invention;

[0029] Figure 3 This is a schematic diagram of the upper mold structure of the present invention;

[0030] Figure 4 This is a schematic diagram showing the location of the flow-damping plate of the present invention;

[0031] Figure 5 This is a schematic diagram of the internal structure of the mold of the present invention;

[0032] Figure 6 This is a schematic diagram of the first material sealing layer injection structure of the present invention;

[0033] Figure 7 This is a schematic diagram of the first material sealing layer injection structure of the present invention;

[0034] Figure 8 This is a schematic diagram of the formation of the first encapsulation layer of the transistor according to the present invention;

[0035] Figure 9 This is a schematic diagram of the formation of the second encapsulation layer of the transistor according to the present invention;

[0036] Figure 10 This is a schematic diagram of the flow-retardant plate structure of the present invention.

[0037] In the diagram: 1. Upper mold; 101. Upper mold cavity; 102. Injection port; 103. Baffle movable groove; 104. Square groove; 105. Connecting groove; 2. Lower mold; 21. Lower mold cavity; 3. Drive assembly; 4. Flow buffer plate; 41. Fence post; 42. Rounded corner; 43. Arc plate; 5. Injection control rod; 6. Cavity; 7. Transistor semiconductor wafer; 71. Connecting gold wire; 8. First material sealing layer; 9. Second material sealing layer; 10. Injection baffle; 11. Connecting frame; 12. Cold water channel. Detailed Implementation

[0038] Please see Figures 1 to 10 This invention provides a multi-point injection molding die for transistor semiconductors, the technical solution of which is as follows:

[0039] Reference Figures 1 to 7A multi-point injection molding die for transistor semiconductors includes an upper die 1, a lower die 2, a driving assembly 3, a flow buffer 4, and an injection control rod 5. Both the upper die 1 and the lower die 2 are square. The upper die 1 has multiple identical upper mold cavities 101, and the lower die 2 has multiple lower mold cavities 21 corresponding to the upper mold cavities 101. When the upper die 1 and the lower die 2 are closed, the upper mold cavities 101 and the lower mold cavities 21 form a cavity 6. The upper die 1 has multiple injection ports 102 located between two adjacent upper mold cavities 101, connecting them. The flow buffer 4 is slidably installed. Inside the upper mold 1, the flow buffer 4 can be limited and moved within the upper mold cavity 101, and the side wall of the flow buffer 4 is located on one side of the injection port 102. The injection control rod 5 is slidably installed inside the injection port 102, and the inside of the injection control rod 5 is connected to the mold injection tube. The drive assembly 3 is fixedly installed above the upper mold 1. The drive assembly 3 controls the movement of the flow buffer 4 and the injection control rod 5 respectively through pneumatic control. A transistor semiconductor chip 7 is placed in the lower mold cavity 21. There are multiple connecting gold wires 71 on the transistor semiconductor. The flow buffer 4 is located above the connecting gold wires 71. The transistor semiconductor chip 7 is injection-encapsulated and formed in the mold cavity. The conductor sheet 7 is held in place at both ends within the lower mold cavity 21. When the upper mold 1 and lower mold 2 are closed, the transistor semiconductor sheet 7 is located in the cavity 6. The injection tube passes through the inside of the injection control rod 5. The liquid encapsulant heated to a molten state is injected under pressure from the bottom of the injection control rod 5 into the injection port 102. The left and right ends of the injection port 102 are connected to two identical mold cavities respectively. The liquid encapsulant flows from the injection port 102 into the mold cavities on both sides. Before injection begins, the drive assembly 3 controls the flow buffer 4 to move vertically downward. The flow buffer 4 changes from a state where the bottom is flush with the top of the upper mold cavity 101 to a state where the bottom extends into the interior of the upper mold cavity 101. When injection begins... When the liquid encapsulant enters the mold cavity, it first contacts the side wall of the buffer plate 4, then gradually wraps around the connecting gold wire 71. Finally, the liquid encapsulant fills the mold cavity and waits for the liquid encapsulant to solidify in the mold. After pressure holding, it reaches a certain hardness, completing the first encapsulation of the transistor semiconductor wafer 7. When the liquid encapsulant is injected under pressure, the buffer plate 4 is used to block and slow down the impact speed of the liquid encapsulant, reduce the impact force on the connecting gold wire 71, and prevent the connecting gold wire 71 from being offset by the impact of the liquid encapsulant, resulting in wire collapse or peeling, causing short circuit or open circuit, and preventing circuit failure and decreased reliability of transistor semiconductor.During the first injection, the bottom of the buffer plate 4 is located inside the upper mold cavity 101. Liquid encapsulant is injected from the bottom of the injection control rod 5 into the injection port 102. The sidewall of the buffer plate 4 is located between the injection port 102 and the connecting gold wire 71. After the first injection, the buffer plate 4 returns to its original position, and the bottom of the buffer plate 4 is flush with the top of the upper mold cavity 101. A first sealing layer 8 is formed on the transistor semiconductor wafer 7. The first sealing layer 8 has multiple grooves. During the second injection, a second sealing layer 9 is formed on the transistor semiconductor wafer 7. During the first injection, the sidewall of the buffer plate 4 is located inside the mold cavity, and the bottom of the injection control rod 5 is located in the middle of the injection port 102. After the first injection is completed and the liquid encapsulant has solidified in the mold, the first sealing layer 8 is formed on the surface of the transistor semiconductor wafer 7. The groove shape on the sealing layer is the same as the groove shape on the sidewall of the buffer plate 4. At this time, the drive assembly 3 controls the buffer plate 4 and the injection... The control lever 5 moves upward, and the bottom of the buffer plate 4 and the bottom of the injection control lever 5 are flush with the top of the upper mold cavity 101. Liquid encapsulant then flows out from the injection control lever 5, filling the grooves of the first encapsulation layer 8 and the empty spaces in the mold cavity. The liquid encapsulant then solidifies in the mold, forming a flat second encapsulation layer 9. The transistor semiconductor wafer 7 has various materials and varying heights, resulting in a thicker product after the first encapsulation. Due to the mismatch in thermal expansion coefficients of different materials on the transistor semiconductor, localized thermal stress occurs, which can cause product warping. The multiple grooves on the first encapsulation layer 8 can release stress in the transistor semiconductor, alleviating warping and preventing excessive warping after encapsulation. This reduces the difficulty of post-encapsulation processes such as ball-mounting, cutting, and die mounting, lowers the defect rate in the production process, and improves the reliability of the transistor semiconductor.

[0040] As one embodiment of the present invention, refer to Figures 5 to 9A baffle movable groove 103 is provided in the upper mold cavity 101, which is connected to the injection port 102. Two identical injection baffles 10 are fixedly installed on both sides of the injection control rod 5. The bottom of the injection baffle 10 is flush with the bottom of the injection control rod 5. The cross-sectional shape of the injection baffle 10 is the same as that of the baffle movable groove 103. The injection baffle 10 and the baffle movable groove 103 are slidably fitted. The injection baffle 10 passes through both ends of the flow buffer 4 and is located above the connecting gold wire 71. The injection baffle 10 is shaped as a rectangular thin plate connecting two identical square plates. When the injection control rod 5 injects material for the first time, the horizontal position of the bottom of the injection baffle 10 is located in the middle of the injection port 102 along with the bottom of the injection control rod 5. The bottom of the injection baffle 10 is located below the baffle movable groove 103. After the first sealing layer 8 is formed, when the drive assembly 3 controls the injection control rod 5 to move upward, the injection baffle 10 moves upward with the injection control rod 5. The injection baffle 10 is located inside the baffle movable groove 103, and the bottom of the injection baffle 10 is flush with the top of the baffle movable groove 103. At this time, the first sealing layer 8 has a groove in the shape of the injection baffle 10, which improves the stress release effect of the transistor semiconductor and alleviates warping. The injection baffle 10 reserves injection space for the second injection. After the first injection is completed, the injection control rod 5 and the injection baffle 10 move upward, leaving remaining space so that the second sealing layer 9 is formed flat. The complete product sealing protects the structure of the transistor semiconductor wafer 7 from damage. To prevent gas oxidation, the internal connecting gold wire 71 is designed to ensure product safety and stability. Furthermore, it eliminates the need for additional injection ports 102 during secondary injection, preventing air from entering the mold and affecting the injection molding effect due to multiple injection ports 102. The upper mold 1 has multiple square grooves 104 inside, within which the flow buffer 4 is limited and moves. The flow buffer 4 is U-shaped, with its two end sidewalls enclosing the connecting gold wire 71. The side walls of the flow buffer 4 are designed as a grid shape composed of multiple grid posts 41, with equal spacing between them. Liquid encapsulant flows into the grid gaps. The edges of the multiple grid posts 41 have rounded corners 42. The U-shaped opening of the flow buffer 4 faces downwards, connecting... The gold wire 71 is located inside the U-shaped opening. When the liquid encapsulant flows and impacts, the flow buffer 4 can provide flow buffer protection for the gold wire 71. The fence-shaped sidewalls allow the liquid encapsulant to flow past the gaps of the fence posts 41 before wrapping the gold wire 71 and the surface of the transistor semiconductor 7. The rounded corners 42 make the flow of the liquid encapsulant more concentrated and gentle. According to Bernoulli's principle, at any cross-section of the same flow tube, the sum of the kinetic energy, potential energy and pressure potential energy of a unit volume of fluid is a constant. When the liquid encapsulant flows past the flow buffer 4, the liquid encapsulant can adhere more evenly to the transistor semiconductor 7, avoiding the situation where some positions on the transistor semiconductor are not filled with encapsulant, thus improving the effect of multi-point filling.A symmetrical arc-shaped plate 43 is arranged on the flow buffer 4. The arc-shaped plate 43 is located on the two side fence posts 41, and the arc surface of the arc plate 43 faces the injection port 102. The distance between the two arc plates 43 is greater than the width of the injection port 102. When the liquid encapsulant flows from the injection port 102 to the mold cavity, the liquid encapsulant that needs to flow through the flow buffer 4 will first contact the arc plate 43 and flow from the arc surface of the arc plate 43 to the gap between the fence posts 41, thus reducing the flow impact of the liquid encapsulant and making the flow of the liquid encapsulant smoother, further improving the effect of multi-point injection. A connecting groove 105 is opened inside the upper mold 1. The connecting groove 105 is located above the square groove 104 and connects... A connecting frame 11 is slidably installed in the groove 105. The bottom of the connecting frame 11 connects the ends of the injection baffles 10 on both sides of the injection control rod 5. When the drive assembly 3 controls the movement of the injection control rod 5, the connecting frame 11 moves in the same direction. When the injection control rod 5 moves upward, it applies an upward pulling force to the end of the injection baffle 10. However, when the injection baffle 10 moves upward to demold, it is subject to the adhesion of the encapsulating material and the uneven pulling force of the injection control rod 5, which may cause the injection baffle 10 to tilt during demolding, causing deformation or damage to the first material seal layer 8. The simultaneous movement of the connecting frame 11 and the injection control rod 5 ensures that the injection baffle 10 is subjected to a uniform upward pulling force, ensuring smooth and complete demolding and improving demolding efficiency. The injection baffle 10 and the connecting frame 11 are both hollow, and the injection baffle 10 and the connecting frame 11 are internally connected. The injection baffles 10 on both sides of the injection control rod 5 are also connected. A cold water channel 12 is provided on the upper mold 1, and one end of the cold water channel 12 is connected to the inside of the connecting frame 11. Each time the injection control rod 5 injects material for encapsulation, cooling water flows into the injection baffle 10 through the cold water channel 12 and circulates continuously. At this time, the injection baffle 10 enhances the cooling effect on the encapsulation material, making the encapsulation material solidify faster. The encapsulation material will shrink during cooling. If the cooling is uneven, it will lead to internal stress concentration. The cooling effect of the injection baffle 10 can reduce internal stress and improve crystal growth. The lifespan of the semiconductor tube; the baffle movable groove 103 is made of shape memory metal material. When the set temperature is reached, the baffle movable groove 103 deforms, and its sidewalls press against the sidewalls of the injection baffle 10. The set temperature is 60℃. When the molten liquid encapsulant flows into the injection port 102, the baffle movable groove 103 expands and deforms, increasing the adhesion between the baffle movable groove 103 and the injection baffle 10. This increases the sealing effect inside the upper mold cavity 101, preventing the entry of external gas and preventing the liquid encapsulant from flowing into the gap between the upper mold 1 and the injection baffle 10, thus improving the injection encapsulation effect of the mold.

[0041] Working principle: The transistor semiconductor chip 7 is placed inside the lower mold 2, with both ends of the transistor semiconductor chip 7 secured within the lower mold cavity 21. When the upper mold 1 and lower mold 2 are closed, the transistor semiconductor chip 7 is located in the cavity 6. At this time, the bottom of the injection control rod 5 and the bottom of the injection baffle 10 are both located in the middle of the injection port 102. The injection tube passes through the inside of the injection control rod 5, and the liquid encapsulant heated to a molten state is injected under pressure from the bottom of the injection control rod 5 into the injection port 102. After the liquid encapsulant solidifies within the mold, the crystal... A first sealing layer 8 is formed on the surface of the semiconductor wafer 7. The drive assembly 3 controls the flow plate 4 and the injection control rod 5 to move upward respectively. The bottom of the flow plate 4 and the bottom of the injection control rod 5 are flush with the top of the upper mold cavity 101. At this time, multiple grooves are formed on the first sealing layer 8. Liquid encapsulant flows out from the injection control rod 5. The liquid encapsulant fills the grooves of the first sealing layer 8 and the empty parts of the mold cavity. Then, wait for the liquid encapsulant to solidify in the mold to form a flat second sealing layer 9. The mold completes multi-point injection.

[0042] The specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and ideas of the present invention should still fall within the protection scope of the present invention.

Claims

1. A multi-point injection molding die for transistor semiconductors, characterized in that, The mold includes an upper mold (1), a lower mold (2), a drive assembly (3), a flow buffer (4), and an injection control rod (5). The upper mold (1) has multiple identical upper mold cavities (101) inside, and the lower mold (2) has multiple lower mold cavities (21) corresponding to the upper mold cavities (101) inside. When the upper mold (1) and the lower mold (2) are closed, the upper mold cavities (101) and the lower mold cavities (21) form a cavity (6). The upper mold (1) has a cold water channel (12) inside, which cools the mold during injection. The upper mold (1) has multiple injection ports (102) inside, which are located in two upper mold cavities (101). Between and connecting two adjacent upper mold cavities (101), the buffer plate (4) is slidably installed inside the upper mold (1), the buffer plate (4) can be limited to move within the upper mold cavity (101), and the side wall of the buffer plate (4) is located on one side of the injection port (102), the injection control rod (5) is slidably installed inside the injection port (102), the drive assembly (3) is fixedly installed above the upper mold (1), the drive assembly (3) controls the movement of the buffer plate (4) and the injection control rod (5) respectively, so that the buffer plate (4) blocks the connecting gold wire (71) on both sides of the injection port (102), and the drive assembly (3) performs secondary injection by controlling the movement of the injection control rod (5).

2. The multi-point injection molding die for transistor semiconductors according to claim 1, characterized in that, The upper mold (1) has multiple square slots (104) inside. Multiple flow buffers (4) are limited to move within the multiple square slots (104). The flow buffers (4) are set in a "U" shape. The connecting gold wires (71) are surrounded inside the flow buffers (4) by the side walls at both ends of the flow buffers (4). The multiple square slots (104) are evenly arranged inside the upper mold (1).

3. The multi-point injection molding die for transistor semiconductors according to claim 2, characterized in that, The upper mold cavity (101) is provided with a baffle movable groove (103), which is connected to the injection port (102). Two identical injection baffles (10) are fixedly installed on both sides of the injection control rod (5). The bottom of the injection baffle (10) is flush with the bottom of the injection control rod (5). The injection baffle (10) is slidably installed in the baffle movable groove (103). The injection baffle (10) passes through both ends of the flow buffer (4) and is located above the connecting gold wire (71). During the first injection, the bottom of the injection baffle (10) is located in the middle of the injection port (102). During the second injection, the bottom of the injection baffle (10) is located at the top of the injection port (102).

4. The multi-point injection molding die for a transistor semiconductor according to claim 3, characterized in that, The two side walls of the flow-retardant plate (4) are configured as a fence shape consisting of multiple fence posts (41), and the edges of the multiple fence posts (41) are provided with rounded corners (42).

5. A multi-point injection molding die for a transistor semiconductor according to claim 4, characterized in that, The flow control plate (4) is symmetrically provided with arc-shaped plates (43), which are located on the fence posts (41) on both sides. The arc surface of the arc-shaped plate (43) faces the injection port (102), and the distance between the two arc-shaped plates (43) is greater than the width of the injection port (102).

6. A multi-point injection molding die for a transistor semiconductor according to claim 3, characterized in that, The upper mold (1) has a connecting groove (105) inside. The connecting groove (105) is located above the square groove (104). A connecting frame (11) is slidably installed in the connecting groove (105). The bottom of the connecting frame (11) connects the ends of the injection baffles (10) on both sides of the injection control rod (5).

7. A multi-point injection molding die for a transistor semiconductor according to claim 6, characterized in that, Both the injection baffle (10) and the connecting frame (11) are hollow. The injection baffle (10) and the connecting frame (11) are internally connected. The injection baffles (10) on both sides of the injection control rod (5) are connected. The cold water channel (12) is internally connected to the connecting frame (11).

8. A multi-point injection molding die for a transistor semiconductor according to claim 7, characterized in that, The sidewall of the baffle movable groove (103) is made of shape memory metal material, and the sidewall of the baffle movable groove (103) expands and deforms when the set temperature is reached.

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