Microcrystalline power module plastic package tooling

Abstract

The utility model discloses a kind of microcrystalline power module plastic package tool, it is related to the field of microelectronic packaging, including die cavity assembly, feeding assembly and thermal control assembly;In die cavity assembly, upper and lower die cavity is connected with three small die cavities by main pipeline equidistant distribution, upper die cavity one corner is provided with feeding cavity and connects three small die cavities, diagonal position is provided with exhaust port, lower die cavity one corner is provided with feeding port and connects feeding cavity;First, second group of heating rod is arranged below three small die cavities and feeding port, is controlled by first temperature sensor;Third group of heating rod is arranged in transition material cavity harver locking mechanism, is controlled by second temperature sensor;Feeding assembly is installed above transition material cavity, including ejector rod, ejector rod mounting bracket, fixed mounting bracket, pressure system, fourth group of heating rod is arranged at the circumference of ejector rod axis, is controlled by third temperature sensor.The utility model tool effectively improves plastic package quality and the integrity and electrical performance of packaging, improves yield while lower plastic package cost.

Description

Technical Field

[0001] This utility model relates to the field of microelectronic packaging technology, and in particular to a microcrystalline power module molding tooling. Background Technology

[0002] Microcrystalline power modules are widely used in power electronics, new energy vehicles, industrial control and other fields. Their packaging quality directly affects the electrical performance and long-term reliability of the modules.

[0003] Currently, traditional molding compound tooling and processes suffer from the following technical problems: 1) Low molding compound utilization and unreasonable runner design: The central barrel of existing molding compound tooling is usually far from the cavity, resulting in a long runner. This leads to significant loss of molding compound during filling, resulting in low utilization. Furthermore, the long runner easily causes injection pressure loss, leading to defects such as pinholes, internal air bubbles, water bubbles, edge gaps, creases, incomplete filling, and missed filling, severely affecting packaging quality. 2) High cost and low production efficiency: Existing molding compound tooling has a complex structure, is expensive, and has high maintenance costs. Moreover, process defects result in a low yield, further increasing production costs. 3) Mismatch in thermal expansion coefficients: Microcrystalline power modules contain components such as capacitors, resistors, and magnetic cores. The thermal expansion coefficients of the adhesive and the molding compound differ. During temperature changes, thermal stress may cause component misalignment, affecting the module's structural stability and electrical performance. 4) Bubble and void defects: Existing injection molding processes are prone to generating bubbles or voids during the filling process, resulting in microscopic defects inside the package, reducing insulation performance and mechanical strength, and may cause partial discharge or thermal failure with long-term use.

[0004] Therefore, there is an urgent need to design a new type of microcrystalline power module molding tooling to optimize the flow channel structure, improve the packaging quality and molding compound utilization, reduce packaging defects, and solve the device misalignment problem caused by thermal expansion coefficient mismatch, thereby improving the overall product yield and reliability. Utility Model Content

[0005] The problem to be solved by this utility model is to provide a microcrystalline power module molding tooling to improve the packaging quality and the utilization rate of molding compound.

[0006] The present invention adopts the following technical solution: a microcrystalline power module molding tooling, comprising: a mold cavity assembly and a feeding assembly, which is controlled by a thermal control assembly externally placed in the control terminal.

[0007] The mold cavity assembly comprises, from bottom to top: a lower mold cavity, an upper mold cavity, and a transition material cavity, with the feeding assembly installed above the transition material cavity;

[0008] The upper and lower mold cavities each contain three small mold cavities that are equidistantly distributed. These three small mold cavities are connected in parallel through a main pipeline to form an integral mold cavity. The upper and lower mold cavities adopt diagonal feeding and discharging. The upper mold cavity has a feeding cavity at one corner, which is connected to the integral mold cavity, and an exhaust port is located at the diagonal position. The lower mold cavity has a feeding port at one corner, which is connected to the feeding cavity.

[0009] The first set of heating rods is arranged below the three small cavities of the upper and lower mold cavities, and the second set of heating rods is arranged below the feed inlet. The heating temperature of the upper and lower mold cavities is controlled by the first temperature sensor.

[0010] The third set of heating rods is arranged in the Haval locking mechanism in the transition material cavity, and the heating temperature of the transition material cavity is controlled by the second temperature sensor;

[0011] The feeding assembly is connected in sequence from bottom to top as follows: push rod, push rod mounting bracket, fixed mounting bracket, and pressure system. The fourth set of heating rods is arranged on the circumference of the push rod axis, and the heating temperature of the push rod is controlled by a third temperature sensor.

[0012] Preferably, the first group of heating rods consists of eighteen rods, divided into six groups of three rods each. Each heating rod has a diameter of 6 mm and a length of 150 mm, and is arranged 9 mm below the three small cavities of the upper and lower mold cavities. The spacing between the heating rods is 18 mm.

[0013] Preferably, the upper mold cavity and the lower mold cavity are fixed by a number of M8 screws with a screw spacing of 4mm; the overall mold cavity is also provided with grooves around its perimeter for installing sealing strips.

[0014] Preferably, the distance between the three small mold cavities is 74mm, the diameter of the feed inlet and the feed cavity is 50mm, and the total height of the upper and lower mold cavities is 44mm.

[0015] Preferably, the second set of heating rods consists of three rods, evenly arranged below the feed inlet. Each heating rod has a diameter of 6mm, a length of 40mm, and a spacing of 16mm. The first temperature sensor is located at the bottom of the three small mold cavities, the feed cavity, and the feed and discharge channels.

[0016] Preferably, the transition cavity is used to expand the material cavity, and the transition cavity is connected to the upper mold cavity by screws, with a sealing ring provided at the connection position; the height of the material cavity is the same as the height of the upper mold cavity, both being 22mm; the inner diameter of the transition cavity is 50mm and the height is 40mm.

[0017] Preferably, two semi-circular Haval locking mechanisms are installed on the outer circle of the transition material cavity, a third set of heating rods is arranged vertically on the Haval locking mechanisms, and a second temperature sensor is set at the center of the Haval locking mechanisms perpendicular to the direction of the third set of heating rods to control the third set of heating rods;

[0018] The two semi-circular Haval locking mechanisms are locked together by screws, and the inner wall of the Haval locking mechanism is pressed against the outer wall of the transition material cavity.

[0019] Preferably, the third group of heating rods consists of eight rods, divided into two groups of four rods each, arranged vertically in the two semi-circular Haver locking mechanisms. Each heating rod has a diameter of 6 mm and a length of 40 mm.

[0020] Preferably, the pressure system is fixed to the top of the fixed mounting frame and is provided with pressure by a cylinder or hydraulic cylinder; the push rod is a shaft-like part that connects to the pressure system and is used for material propulsion; the push rod mounting frame is provided with push rod sealing rings in the axial and radial directions to ensure the airtightness of the push rod during the material cavity propulsion process.

[0021] Preferably, the fourth group of heating rods consists of three rods, each with a diameter of 4 mm and a length of 50 mm, evenly arranged at a 120-degree circumference on the axis of the top rod, and the third temperature sensor is located in the middle of the three heating rods.

[0022] Compared with the prior art, the present invention, by adopting the above technical solution, has the following technical effects:

[0023] 1. The microcrystalline power module molding tooling of this utility model has a feed cylinder close to the three small mold cavities in the mold cavity assembly. The flow channel is short and the utilization rate of molding compound is high. It can effectively avoid problems such as pinholes, internal air bubbles, water bubbles, edge gaps, punching lines, incomplete filling, and missing filling, thereby improving the quality of molding, the integrity of the encapsulation, and the electrical performance.

[0024] 2. The microcrystalline power module molding tooling of this utility model controls the thermal expansion coefficient inside the cavity through a three-layer heating rod control mechanism. Based on three sensors, four sets of heating rods are controlled respectively. When the temperature changes, the capacitance and resistance of the molding material and the module are adjusted in time, which effectively solves the problem that the device may shift when the thermal expansion coefficient of the magnetic core bonding adhesive is mismatched.

[0025] 3. The microcrystalline power module molding tooling of this utility model has a simple structure and low maintenance cost, which increases production output while reducing molding cost. Attached Figure Description

[0026] Figure 1 This is a structural diagram of the microcrystalline power module molding tooling of this utility model;

[0027] Figure 2 This is an exploded view of the microcrystalline power module molding fixture of this utility model;

[0028] Figure 3 This is a structural diagram of the mold cavity of the microcrystalline power module molding tooling of this utility model;

[0029] Figure 4This is a structural diagram of the lower mold cavity of the microcrystalline power module molding tooling of this utility model. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] In one embodiment of this utility model, a microcrystalline power module molding tooling is provided, such as... Figure 1 and Figure 2 As shown, it includes: mold cavity assembly 1, feeding assembly 2, and thermal control assembly, wherein the thermal control assembly is externally located in the control terminal and is used to control the molding of mold cavity assembly 1 and feeding assembly 2.

[0032] Specifically, the mold cavity assembly 1 includes, from bottom to top, a lower mold cavity, an upper mold cavity, and a transition material cavity 12 connected in sequence, and the feeding assembly 2 is installed above the transition material cavity 12.

[0033] In this embodiment, the upper mold cavity and the lower mold cavity structures are as follows: Figure 3 and Figure 4 As shown, three small mold cavities 3 are evenly distributed in both the upper and lower mold cavities. The three small mold cavities 3 in the upper and lower mold cavities are connected in parallel through two main pipelines 4 to form an integral mold cavity. Grooves 5 are also provided around the integral mold cavity for installing sealing strips.

[0034] The upper and lower mold cavities adopt diagonal feeding and discharging. A feeding cavity 7 is set in one corner of the upper mold cavity, which is connected to the overall mold cavity. An exhaust port 11 is set at the diagonal position of the feeding cavity 7 for vacuuming. Correspondingly, a feeding port 6 is set in one corner of the lower mold cavity, which is connected to the feeding cavity 7 of the upper mold cavity.

[0035] Specifically, in this embodiment, the distance between the three small mold cavities 3 is 74mm, the diameter of the feed inlet 6 and the feed cavity 7 is the same, both being 50mm, and the total height of the upper and lower mold cavities is 44mm.

[0036] Several M8 screws were used to fix the upper and lower mold cavities together, with a screw spacing of 4mm, to ensure the airtightness of the mold cavity.

[0037] Furthermore, in order to ensure sufficient filling, a transition material cavity 12 is installed above the upper mold cavity. The transition material cavity 12 is used to expand the feeding cavity 7. The transition material cavity 12 is connected to the upper mold cavity by screws, and a sealing ring 13 is provided at the connection position to ensure the sealing of the cavity.

[0038] Two semi-circular Haval locking mechanisms 14 are installed on the outer circle of the transition material cavity 12. The two semi-circular Haval locking mechanisms 14 are locked by screws, so that the inner wall of the Haval locking mechanism 14 is tightly attached to the outer wall of the transition material cavity 12, ensuring the heat transfer.

[0039] Specifically, in this embodiment, the height of the feed cavity 7 is the same as the height of the upper mold cavity, both being 22mm; the inner diameter of the transition cavity 12 is 50mm and the height is 40mm.

[0040] Furthermore, a feeding assembly 2 is installed above the transition material chamber 12. The feeding assembly 2 is connected in sequence from bottom to top as follows: push rod 17, push rod mounting bracket 18, fixed mounting bracket 19, and pressure system 20.

[0041] The pressure system 20 is fixed to the top of the fixed mounting bracket 19 and is supplied with pressure by a cylinder or hydraulic cylinder; the push rod 17 is a shaft-like part that connects to the pressure system 20 and is used for material propulsion; the push rod mounting bracket 18 is provided with push rod sealing rings 21 in the axial and radial directions respectively to ensure the airtightness of the push rod 17 during the material cavity propulsion process.

[0042] This embodiment uses a four-group heating rod structure, with three temperature sensors controlling the heating rods respectively.

[0043] The first set of heating rods 8 are arranged below the three small mold cavities 3 of the upper and lower mold cavities, and the second set of heating rods 9 are arranged below the feed port 6. The heating temperature of the upper and lower mold cavities is controlled by the first temperature sensor 10.

[0044] The third set of heating rods 15 are arranged in the Haval locking mechanism 14 in the transition material chamber 12, and the heating temperature of the transition material chamber 12 is controlled by the second temperature sensor 16.

[0045] The fourth set of heating rods 22 are arranged around the circumference of the top rod 17 along its axis, and the heating temperature of the top rod 17 is controlled by the third temperature sensor 23.

[0046] Specifically, the first group of heating rods 8 consists of eighteen rods, divided into six groups of three rods each. Each heating rod has a diameter of 6mm and a length of 150mm. They are evenly arranged 9mm below the three small cavities 3 of the upper and lower mold cavities, with a spacing of 18mm between the heating rods.

[0047] The second set of heating rods 9 consists of three rods, evenly arranged below the feed inlet 6. Each heating rod has a diameter of 6mm, a length of 40mm, and a spacing of 16mm.

[0048] The first temperature sensor 10 is located at the bottom of the three small mold cavities 3, the feeding cavity 7, and the feeding and discharging channels. It is used to control the first set of heating rods 8 and the second set of heating rods 9, thereby controlling the overall temperature of the upper mold cavity and the lower mold cavity.

[0049] The third group of heating rods 15 consists of eight rods, divided into two groups of four rods each, which are arranged vertically in the two semi-circular Haver locking mechanisms 14. Each heating rod has a diameter of 6 mm and a length of 40 mm.

[0050] A second temperature sensor 16 is provided at the center of the Haval locking mechanism 14, perpendicular to the direction of the third group of heating rods 15, for controlling the third group of heating rods 15.

[0051] The fourth group of heating rods 22 consists of three rods, each with a diameter of 4 mm and a length of 50 mm, which are evenly arranged at a 120-degree circumference on the axis of the top rod 17.

[0052] The third temperature sensor 23 is located in the middle of the fourth group of heating rods 22 and is used to control the fourth group of heating rods 22.

[0053] In use, first, place the microcrystalline power module to be encapsulated into the three small mold cavities 3 in the mold cavity assembly 1, preload the encapsulation material into the feeding assembly 2, and set the control data in the thermal control assembly, including: temperature, pressure, and curing time.

[0054] Then, the microcrystalline power module to be molded is heat-molded.

[0055] It should be noted that during the heating process, a mismatch in the coefficients of thermal expansion can cause the device to shift, mainly resulting in the failure of the encapsulation layer and the interface between the molded component and the solder joint.

[0056] On the one hand, during temperature changes, the difference in the coefficient of thermal expansion (CTE) between the molding compound and the molded part or lead frame can lead to delamination and cracking. Especially at extreme low temperatures, due to the large difference between the storage temperature and the encapsulation temperature, delamination and cracking can easily occur between the molding compound and the substrate or lead frame.

[0057] On the other hand, the difference in the coefficients of thermal expansion between the molded component and the molding compound can lead to shear stress during temperature changes. For example, the coefficient of thermal expansion of silicon is approximately 2.3 × 10⁻⁶ / ℃, while that of the molding compound is approximately 25 × 10⁻⁶ / ℃. When the temperature changes, their dimensional changes differ significantly, resulting in large displacement and shear stress on the surface of the molded component, which may ultimately lead to failure of the interface between the molded component and the solder joint.

[0058] Therefore, a three-layer heating rod control mechanism is proposed, which takes into account the influence of temperature cycling in the design and avoids geometric abrupt changes and stress concentration, so as to effectively reduce failures caused by thermal stress.

[0059] In use, this embodiment uses a three-layer heating rod control mechanism to control the coefficient of thermal expansion within the cavity. The specific method is as follows:

[0060] The pressure of the feed assembly 2 is controlled by the thermal control component;

[0061] The first set of heating rods 8 and the second set of heating rods 9 are activated, and the heating temperature of the upper and lower mold cavities is controlled by the first temperature sensor;

[0062] The third set of heating rods 15 is activated, and the heating temperature of the transition material chamber 12 is controlled by the second temperature sensor 16.

[0063] The fourth heating rod 22 is activated, and the heating temperature of the top rod 17 is controlled by the third temperature sensor 23.

[0064] Finally, maintain pressure until the molding material is completely filled and enter the curing stage. Control the timing terminal to reach the preset curing time, then turn off the heating. After the temperature drops, remove the packaged part to complete the molding of the microcrystalline power module.

[0065] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A microcrystalline power module plastic packaging tool, characterized in that, include: The mold cavity assembly (1) and the feeding assembly (2) are controlled by a thermal control assembly located on the control terminal. The mold cavity assembly (1) includes, from bottom to top, a lower mold cavity, an upper mold cavity, and a transition material cavity (12), and the feeding assembly (2) is installed above the transition material cavity (12); The upper and lower mold cavities each contain three small mold cavities (3) that are equidistantly distributed. The three small mold cavities (3) are connected in parallel through the main pipeline (4) to form an integral mold cavity. The upper and lower mold cavities adopt diagonal feeding and discharging. A feeding cavity (7) is provided at one corner of the upper mold cavity, which is connected to the integral mold cavity. An exhaust port (11) is provided at the diagonal position. A feeding port (6) is provided at one corner of the lower mold cavity, which is connected to the feeding cavity (7). The first set of heating rods (8) is arranged below the three small cavities (3) of the upper and lower mold cavities, and the second set of heating rods (9) is arranged below the feed inlet (6). The heating temperature of the upper and lower mold cavities is controlled by the first temperature sensor (10). The third set of heating rods (15) is arranged in the Haval locking mechanism (14) in the transition material cavity (12), and the heating temperature of the transition material cavity (12) is controlled by the second temperature sensor (16); The feeding assembly is connected from bottom to top as follows: top rod (17), top rod mounting bracket (18), fixed mounting bracket (19), pressure system (20), and a fourth set of heating rods (22) arranged on the circumference of the top rod (17) axis. The heating temperature of the top rod (17) is controlled by the third temperature sensor (23).

2. The microcrystalline power module plastic packaging tooling of claim 1, wherein, The first group of heating rods (8) consists of eighteen rods, divided into six groups of three rods each. Each heating rod has a diameter of 6 mm and a length of 150 mm. They are arranged 9 mm below the three small cavities (3) of the upper and lower mold cavities, and the spacing between the heating rods is 18 mm.

3. The microcrystalline power module plastic packaging tooling of claim 1, wherein, The upper mold cavity and the lower mold cavity are fixed by several M8 screws with a screw spacing of 4mm; The overall mold cavity is also provided with grooves (5) around its perimeter for installing sealing strips; The distance between the three small mold cavities (3) is 74mm, the diameter of the feed port (6) and the feed cavity (7) is 50mm, and the total height of the upper and lower mold cavities is 44mm.

4. The microcrystalline power module molding tooling according to claim 2, characterized in that, The second group of heating rods (9) consists of three rods, which are evenly arranged below the feed inlet (6). Each heating rod has a diameter of 6 mm, a length of 40 mm, and a spacing of 16 mm. The first temperature sensor (10) is located between the upper and lower mold cavities.

5. The microcrystalline power module molding tooling according to claim 1, characterized in that, The transition cavity (12) is used to expand the feed cavity (7). The transition cavity (12) is connected to the upper mold cavity by screws, and a sealing ring (13) is provided at the connection position. The height of the feed cavity (7) is the same as that of the upper mold cavity, which is 22mm. The inner diameter of the transition cavity (12) is 50mm and the height is 40mm.

6. The microcrystalline power module molding tooling according to claim 1, characterized in that, Two semi-circular Haval locking mechanisms (14) are installed on the outer circle of the transition material cavity (12). A third set of heating rods (15) is arranged vertically on the Haval locking mechanism (14), and a second temperature sensor (16) is set in the center of the Haval locking mechanism (14) in a direction perpendicular to the third set of heating rods (15) to control the third set of heating rods (15). Two semi-circular Haval locking mechanisms (14) are locked by screws, and the inner wall of the Haval locking mechanism (14) is pressed against the outer wall of the transition material cavity (12).

7. The microcrystalline power module molding tooling according to claim 6, characterized in that, The third group of heating rods (15) consists of eight rods, divided into two groups of four rods each, which are arranged vertically on the two semi-circular Haver locking mechanisms (14). Each heating rod has a diameter of 6 mm and a length of 40 mm.

8. The microcrystalline power module molding tooling according to claim 1, characterized in that, The pressure system (20) is fixed to the top of the fixed mounting bracket (19) and is supplied with pressure by a cylinder or hydraulic cylinder; The push rod (17) is a shaft-like part that connects to the pressure system (20) and is used for material propulsion; The push rod mounting bracket (18) is provided with push rod sealing rings (21) in the axial and radial directions respectively, which are used to ensure the airtightness of the push rod (17) during the material chamber propulsion process.

9. The microcrystalline power module molding tooling according to claim 8, characterized in that, The fourth group of heating rods (22) consists of three rods, each with a diameter of 4 mm and a length of 50 mm. They are evenly arranged at a 120-degree circumference position on the axis of the top rod (17). The third temperature sensor (23) is located in the middle of the three heating rods.

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