Method for reducing backfilling rate of plastic package and chip module

Abstract

The method comprises a substrate and chips mounted on the substrate in a matrix arrangement mode, baffles are arranged on the substrate according to the injection position of a plastic package material on the substrate and the mold flow direction, the baffles are located in front of the chips and staggered with the chips in the mold flow direction, the arrangement direction of the baffles is perpendicular to the mold flow direction, and the mold flow direction of the baffles is perpendicular to the mold flow direction. The number, the size, the position and the shape of the baffles are adjusted so as to adjust the flow speed of the plastic package material around the chip and reduce the encapsulation backfilling rate during plastic package. According to the invention, the flow rate of the plastic package material around the chip is more uniform, a layered decreasing filling structure is prevented from being formed around the chip, the plastic package backfill rate is reduced, bubbles in the plastic package material and gas in the mold cavity can be effectively discharged in the plastic package process, so that cavities in a product are reduced, and the product quality is improved. On the basis that the integration level of an integrated circuit is not reduced, the plastic packaging reliability is improved, and the packaging quality of a chip is improved. The invention further provides a chip module.

Description

Technical Field

[0001] The invention relates to a method for improving chip plastic packaging filling cavities and a chip module, belonging to the technical field of chip plastic packaging. Background Art

[0002] Chip packaging technology plays a vital role in the modern electronic manufacturing process. The packaging quality directly affects the performance and life of the chip. With the development trend of electronic equipment towards high performance, miniaturization and multifunctionality, higher requirements are placed on the packaging technology of integrated circuits. High-quality packaging can not only protect the chip from the external environment, but also ensure the stability of electrical connections and reliable thermal management.

[0003] The packaging technology of integrated circuits requires integrating chips with different functions in the same system-level packaging module. First, the baffle is welded to the substrate through surface mounting technology, and then the chip is mounted on the substrate with adhesive. Next, the signal connection between the chip and the substrate is achieved through wire bonding, and then plastic sealing is performed. Since the chip will hinder the plastic sealing material on the path through which the plastic sealing material flows, this results in a fast flow rate of the plastic sealing material in the non-chip area and a slow flow rate of the plastic sealing material in the chip area. In the case of a large chip thickness, when the plastic sealing material passes through the chip, the inconsistent flow rate of the plastic sealing material around the chip will form a "layered" decreasing filling structure, resulting in the occurrence of encapsulation backfilling and ultimately forming voids. In addition, the influence of multiple factors such as the amount of plastic sealing material, flow rate, glue application path, and bubbles in the glue itself also lead to the occurrence of voids, which reduces the packaging quality of the product and seriously affects the performance and life of the product. Summary of the invention

[0004] The method for reducing the plastic encapsulation backfill rate provided by the present invention not only makes the flow rate of the plastic encapsulation material around the chip more uniform, prevents the formation of a "layered" decreasing filling structure around the chip, and reduces the plastic encapsulation backfill rate, but also can effectively discharge bubbles in the plastic encapsulation material and gas in the mold cavity during the plastic encapsulation process, thereby reducing voids in the product, improving the plastic encapsulation reliability without reducing the integrated circuit integration, and improving the chip packaging quality. The present invention also provides a chip module.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for reducing the backfill rate of plastic encapsulation includes a substrate and chips mounted on the substrate in a matrix arrangement, characterized in that a baffle is arranged on the substrate according to the injection position of the plastic encapsulation material on the substrate and the mold flow direction, the baffle is located in front of the chip and staggered with the chip in the mold flow direction, the arrangement direction of the baffle is perpendicular to the mold flow direction, the number, size, position and shape of the baffle are adjusted to adjust the flow rate of the plastic encapsulation material around the chip, and reduce the backfill rate of the plastic encapsulation during plastic encapsulation.

[0007] Preferably, the position of the baffle is adjusted according to the arrangement position of the chip, and the baffle is distributed alternately with the front row chips in the arrangement direction; the number of baffles is adjusted according to the number of chip gaps along the mold flow direction; the size and shape of the baffle are adjusted according to the injection flow rate of the molding compound and the size of the chip.

[0008] Preferably, the cross section of the baffle is rectangular, semicircular or stepped mountain shape.

[0009] Preferably, a guide groove is provided on the substrate, which is located in front of the chip and parallel to the arrangement direction of the baffle, and the end of the guide groove passes through the side of the substrate, and the baffle is guided from the side of the substrate to fit into the guide groove.

[0010] Preferably, a movable positioning rod is installed on the baffle, and a positioning groove parallel to and connected with the guide groove is provided at the bottom of the guide groove, and the baffle is positioned in the guide groove as the positioning rod is inserted into the positioning groove.

[0011] Preferably, the positioning rod includes a rod body that is clearance-fitted through the baffle, a plug handle arranged at the top of the rod body, and a spherical plug bottom arranged at the bottom of the rod body. The spherical plug bottom is inserted into the positioning groove and clamped by the positioning groove as the plug handle is pressed down, or is separated from the positioning groove as the plug handle is lifted up.

[0012] Preferably, the flow rate V2 of the plastic encapsulation material after passing through the baffle is calculated according to the following formula, and the size, position and number of the baffle are adjusted to form an adjustment of the flow rate V2 of the plastic encapsulation material after passing through the baffle;

[0013]

[0014] Where V1 is the injection flow rate of the molding compound, η is the viscosity of the molding compound, P is the injection pressure of the molding compound, T is the temperature of the molding compound, N1 is the number of baffles, S1 is the contact area between the baffle and the molding compound, N2 is the number of chip gaps along the mold flow direction, L2 is the width of the chip gap along the mold flow direction, and H2 is the height of the chip.

[0015] Preferably, when the cross section of the baffle is rectangular, the flow rate V2 of the plastic encapsulation material after passing through the baffle is calculated according to the following formula:

[0016]

[0017] Where L1 is the width of the baffle, and H1 is the height of the baffle.

[0018] A chip module using the above-described method for reducing the backfill rate of plastic encapsulation includes a substrate and chips mounted on the substrate in a matrix arrangement, and is characterized in that it also includes a baffle mounted on the substrate, the baffle is located in front of the chip and is staggered with the chip in the mold flow direction, and the arrangement direction of the baffle is perpendicular to the mold flow direction.

[0019] The beneficial effects of the invention are:

[0020] The method for reducing the backfill rate of plastic encapsulation described above sets a baffle according to the injection position of the plastic encapsulation material on the substrate and the mold flow direction, sets the baffle in front of the chip and staggered with the chip in the mold flow direction, and the arrangement direction of the baffle is perpendicular to the mold flow direction. When the plastic encapsulation material enters the mold cavity formed by the substrate and the mold, the baffle hinders the flow of the plastic encapsulation material, and effectively reduces the flow rate of the plastic encapsulation material in the chip gap along the mold flow direction. According to the injection flow rate of the plastic encapsulation material, the thickness of the chip and the arrangement structure, the number, size, position and shape of the baffles are adjusted to make the flow rate of the plastic encapsulation material in the chip gap along the mold flow direction and the flow rate on the chip The speed is closer, and the plastic encapsulation compound can evenly cover the substrate at a relatively uniform flow rate, which not only makes the flow rate of the plastic encapsulation compound around the chip more uniform, prevents the formation of a "layered" decreasing filling structure around the chip, and reduces the plastic encapsulation backfill rate, but also can effectively discharge the bubbles in the plastic encapsulation compound and the gas in the mold cavity during the plastic encapsulation process, thereby reducing the voids in the product. The baffle is only set in front of the chip, does not affect the arrangement and mounting of the chip, does not occupy the space around the chip, and does not interfere with the wire bonding operation between the chip and the substrate. It improves the plastic encapsulation reliability and the chip packaging quality without reducing the integration of the integrated circuit.

[0021] The position of the baffle is adjusted according to the arrangement position of the chip, so that the baffle is arranged in the chip gap along the mold flow direction and is distributed alternately with the front row chips. The number of baffles is adjusted according to the number of chip gaps along the mold flow direction, so that the flow rate of the plastic encapsulation material in the chip gaps along the mold flow direction is reduced. The size of the baffle is adjusted according to the injection flow rate of the plastic encapsulation material and the thickness of the chip, so that the flow rate of the plastic encapsulation material in the chip gap along the mold flow direction is equivalent to the flow rate of the plastic encapsulation material passing through the chip, thereby preventing the formation of a "layered" decreasing filling structure around the chip and reducing the plastic encapsulation backfill rate. The shape of the baffle is adjusted according to the injection flow rate of the plastic encapsulation material to buffer and drain the injection impact of the plastic encapsulation material, effectively discharge the bubbles in the plastic encapsulation material, and make the plastic encapsulation material evenly distributed in the plastic encapsulation mold cavity, thereby improving the plastic encapsulation reliability and the packaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the distribution of the baffle with a rectangular cross section and the chip on the substrate.

[0023] Figure 2 Schematic diagram of the distribution of baffles and chips with semicircular cross-sections on the substrate.

[0024] Figure 3 Schematic diagram of a baffle having a stepped mountain-shaped cross section.

[0025] Figure 4 Schematic diagram of a baffle with a positioning rod.

[0026] Figure 5 This is a schematic diagram of the spherical bottom plug of the positioning rod extending into the positioning groove to position the baffle in the guide groove. DETAILED DESCRIPTION

[0027] Combine the following Figures 1 to 5 The embodiments of the present invention are described in detail.

[0028] The method for reducing the backfill rate of plastic encapsulation includes a substrate 1 and chips 2 arranged in a matrix and mounted on the substrate 1, characterized in that a baffle 3 is arranged on the substrate 1 according to the injection position of the plastic encapsulation material on the substrate 1 and the mold flow direction, the baffle 3 is located in front of the chip 2 and is staggered with the chip 2 in the mold flow direction, the arrangement direction of the baffle 1 is perpendicular to the mold flow direction, and the number, size, position and shape of the baffle 3 are adjusted to adjust the flow rate of the plastic encapsulation material around the chip to reduce the backfill rate of the plastic encapsulation.

[0029] The method for reducing the backfill rate of plastic encapsulation described above is to set a baffle 3 according to the injection position of the plastic encapsulation material on the substrate 1 and the mold flow direction, and to set the baffle 3 in front of the chip 2 and staggered with the chip 2 in the mold flow direction. The arrangement direction of the baffle 3 is perpendicular to the mold flow direction. When the plastic encapsulation material enters the mold cavity formed by the substrate and the mold, the baffle hinders the flow of the plastic encapsulation material, and effectively reduces the flow rate of the plastic encapsulation material in the chip gap 4 along the mold flow direction. According to the injection flow rate of the plastic encapsulation material, the thickness of the chip and the arrangement structure, the number, size, position and shape of the baffles are adjusted to make the flow rate of the plastic encapsulation material in the chip gap 4 along the mold flow direction and the flow rate of the plastic encapsulation material in the chip gap 4 along the mold flow direction and the flow rate of the plastic encapsulation material in the chip gap 4 along the mold flow direction. The flow rate on the chip is closer, and the plastic encapsulation compound can evenly cover the substrate at a relatively uniform flow rate, which not only makes the flow rate of the plastic encapsulation compound around the chip more uniform, prevents the formation of a "layered" decreasing filling structure around the chip, and reduces the plastic encapsulation backfill rate, but also can effectively discharge bubbles in the plastic encapsulation compound and gas in the mold cavity during the plastic encapsulation process, thereby reducing voids in the product. The baffle is only set in front of the chip, which does not affect the arrangement and mounting of the chip, does not occupy the space around the chip, and does not interfere with the wire bonding operation between the chip and the substrate. It improves the plastic encapsulation reliability and the chip packaging quality without reducing the integration of the integrated circuit.

[0030] Among them, the position of the baffle 3 is adjusted according to the arrangement position of the chip 2, and the baffle 3 is alternately distributed with the front row chips 2 in the arrangement direction; the number of baffles 3 is adjusted according to the number of chip gaps 4 along the mold flow direction; the size and shape of the baffle are adjusted according to the injection flow rate of the molding compound and the size of the chip. The position of the baffle is adjusted according to the arrangement position of the chip 2, so that the baffle 3 is arranged in the chip gap 4 along the mold flow direction and is distributed alternately with the front row of chips 2. The number of baffles 3 is adjusted according to the number of chip gaps 4 along the mold flow direction, so that the flow rate of the plastic encapsulation material in the chip gap 4 along the mold flow direction is reduced. The size of the baffle 3 is adjusted according to the injection flow rate of the plastic encapsulation material and the thickness of the chip 2, so that the flow rate of the plastic encapsulation material in the chip gap 4 along the mold flow direction is equivalent to the flow rate of the plastic encapsulation material passing through the chip, thereby preventing the formation of a "layered" decreasing filling structure around the chip and reducing the plastic encapsulation backfill rate. The shape of the baffle 3 is adjusted according to the injection flow rate of the plastic encapsulation material to buffer and drain the injection impact of the plastic encapsulation material, effectively discharge the bubbles in the plastic encapsulation material, and make the plastic encapsulation material evenly distributed in the plastic encapsulation mold cavity, thereby improving the plastic encapsulation reliability and the packaging quality.

[0031] The cross section of the baffle 3 is rectangular, semicircular or stepped peak shape. The rectangular baffle 3 is simple to shape and can effectively hinder the flow of the plastic encapsulation material, making the flow of the plastic encapsulation material around the chip more uniform, so that the plastic encapsulation material can evenly cover the chip and its surroundings, reducing the plastic encapsulation material passing through the chip to form a "layered" decreasing structure, reducing the formation of voids, and the cross section of the baffle 3 is semicircular, which can not only play the same role as the baffle 3 with a rectangular cross section, but also withstand the instantaneous impact force of the injection of the plastic encapsulation material through the semicircular convex surface, forming an instantaneous reduction in the flow rate of the plastic encapsulation material, and making the plastic encapsulation material flow along the semicircular convex surface, preventing The chip gap 4 along the mold flow direction becomes a channel for high-speed flow of the encapsulating material, which improves the balance of the flow rate of the encapsulating material around the chip, thereby effectively reducing the encapsulation backfill rate. The cross-section of the baffle 3 is in the shape of a stepped peak, which not only plays the same role as the baffle 3 with a semicircular cross-section, but also forms multiple buffering and deceleration effects on the encapsulating material through the contact between the stepped peak-shaped surface and the encapsulating material, so that the encapsulating material can evenly cover the substrate at a relatively uniform flow rate, and can effectively discharge bubbles in the encapsulating material and gas in the mold cavity during the encapsulation process, thereby reducing voids in the product.

[0032] A guide groove 11 is provided on the substrate 1, which is located in front of the chip and parallel to the arrangement direction of the baffle. The end of the guide groove 11 passes through the side of the substrate, and the baffle 3 is guided from the side of the substrate to fit into the guide groove 11. The setting of the guide groove 11 facilitates the adjustment of the position of the baffle 3 along the arrangement direction on the substrate 1, so that the position of the baffle can be adjusted according to the arrangement position of the chip 2, so that the baffle 3 is arranged in the chip gap 4 along the mold flow direction and is alternately distributed with the front row of chips 2, and the flow rate of the plastic encapsulation material in the chip gap 4 along the mold flow direction is effectively reduced.

[0033] The baffle plate 3 is provided with a movable positioning rod 5, and a positioning groove 12 is provided at the bottom of the guide groove 11, which is parallel to and connected with the guide groove 11. The baffle plate 3 is positioned in the guide groove 11 as the positioning rod 5 is inserted into the positioning groove 12. The baffle plate 3 is positioned in the guide groove 11 by inserting the positioning rod 5 into the positioning groove 12, so as to prevent the plastic sealing material from pushing the baffle plate 3 to move in the guide groove 11 during the plastic sealing process, and effectively position the baffle plate 3, so as to ensure that the baffle plate 3 forms an obstacle to the flow of the plastic sealing material in the chip gap 4 along the film flow direction.

[0034] The positioning rod 5 comprises a rod body 51 which penetrates the baffle 3 with clearance fit, a plug handle 52 arranged at the top of the rod body 5, and a spherical plug bottom 53 arranged at the bottom of the rod body 51. The spherical plug bottom 53 is inserted into the positioning groove 12 and clamped by the positioning groove 12 as the plug handle 52 is pressed down, or is separated from the positioning groove 12 as the plug handle 52 is lifted up. The spherical plug bottom 53 is spherical and can be pressed into the positioning groove 12 by pressing the plug handle 52 to position the baffle 3, or the plug handle 52 can be lifted up to pull the spherical plug bottom 53 out of the positioning groove 12, so that the baffle 3 can move in the guide groove 11 to adjust the position.

[0035] The flow rate V2 of the plastic encapsulation material after passing through the baffle is calculated according to the following formula, and the size, position and number of the baffle are adjusted to adjust the flow rate V2 of the plastic encapsulation material after passing through the baffle;

[0036]

[0037] Wherein V1 is the injection flow rate of the molding compound, η is the viscosity of the molding compound, P is the injection pressure of the molding compound, T is the temperature of the molding compound, N1 is the number of baffles, S1 is the contact area between the baffle and the molding compound, N2 is the number of chip gaps 4 along the mold flow direction, L2 is the width of the chip gap 4 along the mold flow direction, and H2 is the height of the chip.

[0038] Since the flow rate of the plastic encapsulation material is inversely proportional to the degree of obstruction of the baffle to the flow path, the sum of the contact areas of multiple baffles and the plastic encapsulation material is N1×S1, and the longitudinal cross-sectional area of ​​the chip gap along the mold flow direction is N2×L2×H2. The degree of obstruction can be expressed by the ratio of the sum of the contact areas of multiple baffles and the plastic encapsulation material to the longitudinal cross-sectional area of ​​the chip gap along the mold flow direction, and the following formula 1 can be obtained:

[0039]

[0040] Among them, C is a proportional coefficient, which depends on the process parameters such as the viscosity of the molding compound, injection pressure, temperature, and the shape and arrangement of the baffles. Since the flow rate of the molding compound is proportional to the injection pressure P and inversely proportional to the viscosity η, and the temperature T affects the viscosity η, generally, the viscosity decreases as the temperature increases. The obstruction coefficient C can be considered as a measure of the reduction in flow rate caused by the presence of the baffle. Therefore, the obstruction coefficient C is proportional to the viscosity η, inversely proportional to the injection pressure P, and inversely proportional to the temperature T. Therefore, the relationship between the obstruction coefficient C and the viscosity η, injection pressure P, temperature T, and the number and size of the baffles can be expressed as Substituting the above formula into Formula 1, we can get the calculation formula of the flow rate V2 of the plastic encapsulation material after passing through the baffle as the following Formula 2:

[0041]

[0042] In practical applications, it is necessary to optimize the size, number and position of the baffles through experiments and calculate the flow rate V2 of the plastic sealing material after passing through the baffles to achieve the best plastic sealing effect.

[0043] When the cross section of the baffle is a rectangle, the flow rate V2 of the plastic encapsulation material after passing through the baffle is calculated according to the following formula 3:

[0044]

[0045] Where L1 is the width of the baffle, and H1 is the height of the baffle.

[0046] When the cross section of the baffle 3 is a rectangle, the area of ​​the contact surface between the baffle and the plastic packaging material is S1 = L1 × H1. Substituting it into the above formula 2, we get formula 3, which is more convenient and simple to calculate.

[0047] The following Table 1 is a list of the molding compound flow rate V2 after passing the baffle calculated by Formula 3 based on the physical parameters of the molding compound, the size and number of the baffles, and the number and size of the chips, and the corresponding molding compound flow rate V2 after passing the baffle monitored by the analysis software during the simulated molding filling process.

[0048] Table 1

[0049]

[0050] It can be seen from Table 1 that the difference between the value of V2 calculated by Formula 3 and the corresponding value of V2 monitored by the analysis software during the simulated plastic encapsulation filling process does not exceed 0.2 mm / s, indicating that the plastic encapsulation material flow rate V2 after passing the baffle calculated by Formula 3 meets the error requirements compared with the plastic encapsulation material flow rate V2 after passing the baffle during the simulated plastic encapsulation filling process. It is feasible to calculate the plastic encapsulation material flow rate V2 after passing the baffle by Formula 3. The size, number and shape of the baffle can be adjusted to adjust the plastic encapsulation material flow rate V2 after passing the baffle, thereby adjusting the flow rate of the plastic encapsulation material around the chip to achieve the purpose of reducing the encapsulation backfill rate during plastic encapsulation.

[0051] The present invention also protects a chip module that adopts the above-mentioned method for reducing the backfill rate of plastic encapsulation, including a substrate 1 and chips 2 mounted on the substrate 1 in a matrix arrangement, characterized in that it also includes a baffle 3 mounted on the substrate 1, the baffle 3 is located in front of the chip 2 and is staggered with the chip 2 in the mold flow direction, and the arrangement direction of the baffle 1 is perpendicular to the mold flow direction.

[0052] In the chip module described above, the baffle 3 is arranged in front of the chip 2 and staggered with the chip 2 in the mold flow direction. The arrangement direction of the baffle 3 is perpendicular to the mold flow direction. When the molding compound enters the mold cavity formed by the substrate and the mold, the baffle hinders the flow of the molding compound, and effectively reduces the flow rate of the molding compound in the chip gap 4 along the mold flow direction, so that the flow rate of the molding compound in the chip gap 4 along the mold flow direction is closer to the flow rate on the chip. The molding compound can evenly cover the substrate at a relatively uniform flow rate, which not only makes the flow rate of the molding compound around the chip more uniform, prevents the formation of a "layered" decreasing filling structure around the chip, and reduces the plastic encapsulation backfill rate, but also can effectively discharge bubbles in the molding compound and gas in the mold cavity during the molding process, thereby reducing voids in the product. The baffle is only arranged in front of the chip, does not affect the arrangement and mounting of the chip, does not occupy the space around the chip, does not interfere with the chip and substrate lead bonding operation, improves the molding reliability without reducing the integration of the integrated circuit, and improves the packaging quality of the chip.

[0053] The above is a complete description of the technical solutions of the embodiments of the present invention in conjunction with the accompanying drawings. It should be noted that the described embodiments are only part of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

Claims

1. A method for reducing the backfill rate of a plastic package, comprising a substrate and chips mounted on the substrate in a matrix arrangement, characterized in that: A baffle is set on the substrate according to the injection position of the plastic encapsulation material on the substrate and the mold flow direction. The baffle is located in front of the chip and staggered with the chip in the mold flow direction. The arrangement direction of the baffle is perpendicular to the mold flow direction. The number, size, position and shape of the baffle are adjusted to adjust the flow rate of the plastic encapsulation material around the chip and reduce the encapsulation backfill rate during plastic encapsulation.

2. The method for reducing the plastic encapsulation backfill rate according to claim 1, characterized in that: The position of the baffle is adjusted according to the arrangement position of the chip, and the baffle is distributed alternately with the front row chips in the arrangement direction; the number of baffles is adjusted according to the number of chip gaps along the mold flow direction; the size and shape of the baffle are adjusted according to the injection flow rate of the plastic encapsulation material and the size of the chip.

3. The method for reducing the plastic encapsulation backfill rate according to claim 1, characterized in that: The cross section of the baffle is rectangular, semicircular or stepped mountain shape.

4. The method for reducing the plastic encapsulation backfill rate according to claim 1, characterized in that: A guide groove is provided on the substrate, which is located in front of the chip and parallel to the arrangement direction of the baffle. The end of the guide groove passes through the side of the substrate. The baffle is guided from the side of the substrate and inserted into the guide groove.

5. The method for reducing the plastic encapsulation backfill rate according to claim 4, characterized in that: A movable positioning rod is arranged on the baffle plate, a positioning groove which is parallel to and connected with the guide groove is arranged at the bottom of the guide groove, and the baffle plate is positioned in the guide groove as the positioning rod is inserted into the positioning groove.

6. The method for reducing the plastic encapsulation backfill rate according to claim 4, characterized in that: The positioning rod includes a rod body that passes through the baffle with a clearance fit, a plug handle arranged at the top of the rod body, and a spherical plug bottom arranged at the bottom of the rod body. The spherical plug bottom is inserted into the positioning groove and clamped by the positioning groove as the plug handle is pressed down, or is separated from the positioning groove as the plug handle is lifted up.

7. The method for reducing the plastic encapsulation backfill rate according to claim 2, characterized in that: The flow rate V2 of the plastic encapsulation material after passing through the baffle is calculated according to the following formula, and the size, position and number of the baffle are adjusted to adjust the flow rate V2 of the plastic encapsulation material after passing through the baffle; Where V1 is the injection flow rate of the molding compound, η is the viscosity of the molding compound, P is the injection pressure of the molding compound, T is the temperature of the molding compound, N1 is the number of baffles, S1 is the contact area between the baffle and the molding compound, N2 is the number of chip gaps along the mold flow direction, L2 is the width of the chip gap along the mold flow direction, and H2 is the height of the chip.

8. The method for reducing the plastic encapsulation backfill rate according to claim 7, characterized in that: When the cross section of the baffle is rectangular, the flow rate V2 of the plastic encapsulation material after passing through the baffle is calculated according to the following formula: Where L1 is the width of the baffle, and H1 is the height of the baffle.

9. A chip module using the method for reducing the plastic encapsulation backfill rate according to any one of claims 1 to 8, comprising a substrate and chips mounted on the substrate in a matrix arrangement, characterized in that: It also includes a baffle installed on the substrate. The baffle is located in front of the chip and staggered with the chip in the mold flow direction. The arrangement direction of the baffle is perpendicular to the mold flow direction.

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