Semiconductor packaging injection mold

Abstract

The invention relates to the technical field of injection molds, and discloses a semiconductor packaging injection mold which comprises a fixed mold, a movable mold, a supporting table, a double-shaft telescopic air cylinder, an injection molding cavity, a multi-point controllable ejector pin mechanism, a hydraulic demolding mechanism and the like. According to the mold, balanced closing and separation of the movable mold are achieved through the double-shaft telescopic air cylinder, the injection molding cavity is matched with the surface of a semiconductor packaging product, and the accuracy of the sealing cavity is ensured. The multi-point controllable ejector pin mechanism is composed of ejector pins, reset springs and magnetic pushing assemblies, the ejector pins are distributed in a matrix mode, and damage to packaged products is reduced. And the hydraulic demolding mechanism realizes uniform injection of a demolding agent through a conveying hole, a liquid guide pipe and an anti-reflux valve, so that the stability and no damage in the demolding process are ensured. According to the mold, automatic control is combined, synchronous forming of the double injection molding cavities is achieved, the productivity is effectively improved, silicone oil emulsion is adopted as a release agent, a lubricating film is formed, and the production efficiency and the product quality are improved.

Description

Technical Field

[0001] The invention relates to the technical field of injection molds, in particular to a semiconductor packaging injection mold. Background Art

[0002] Semiconductor packaging injection molding is a key semiconductor manufacturing process that provides protection, electrical connection and heat dissipation by encapsulating chips and lead frames in plastic materials. The process includes chip mounting, wire bonding, injection molding, and post-curing, and relies on precise material selection, mold design and injection molding process parameters, as well as automated control systems and visual inspection technology to ensure packaging quality and efficiency. It has a wide range of applications, covering consumer electronics, automotive electronics, industrial control and communication equipment, etc., and is used to manufacture chip packaging in smartphones, automotive ECUs, industrial robot controllers and communication equipment.

[0003] Traditional injection molds use an ejector design, and usually only one ejector directly acts on the product, which results in excessive demoulding force and may also cause damage to the chip or lead frame; inaccurate resetting affects production efficiency.

[0004] Therefore, we propose a semiconductor packaging injection mold to solve the problems in the above background. Summary of the invention

[0005] The object of the present invention is to provide a semiconductor packaging injection mold to solve the problem that the conventional injection mold adopts an ejector pin design, which leads to excessive demoulding force and damages the chip or lead frame.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A semiconductor packaging injection mold comprises a fixed mold and a movable mold, wherein the fixed mold is fixedly connected to a support platform on a side away from the movable mold, and a telescopic cylinder is installed on a side of the movable mold away from the fixed mold. The movable mold is provided with an injection cavity adapted to the surface of the semiconductor, and a multi-point controllable ejector mechanism and a hydraulic demolding mechanism for stable demolding are installed inside the movable mold.

[0008] Preferably, the multi-point controllable ejector mechanism comprises an ejector, a return spring and a magnetic push assembly. A control groove is provided inside the movable mold. The magnetic push assembly and the return spring are installed inside the control groove. A telescopic hole is connected between the control groove and the injection cavity. The ejector is slidably connected inside the telescopic hole. The magnetic push assembly pushes the ejector to slide from the telescopic hole to the injection cavity. The return spring pushes the ejector to retract inside the control groove.

[0009] Preferably, a plurality of ejector pins are provided and distributed in a matrix inside the injection cavity. When the movable mold is performing injection molding, the magnetic pushing assembly does not push the ejector pin, and the return spring pushes the ejector pin to retract into the control groove, so that one end of the ejector pin close to the injection cavity remains flush with the cavity wall of the injection cavity.

[0010] Preferably, the magnetic pushing assembly includes an electromagnet plate and a permanent magnet plate, the electromagnet plate is fixedly mounted at one end of the control slot away from the telescopic hole, the end of the ejector pin located inside the control slot is fixedly connected to the permanent magnet plate, and the permanent magnet plate is slidably connected inside the control slot.

[0011] Preferably, one end of the return spring is fixedly connected to the inner wall of one end of the telescopic hole connected to the control slot, and the other end is fixedly connected to the permanent magnet plate, and the return spring pushes the permanent magnet plate toward the electromagnet plate.

[0012] Preferably, the ejector pin comprises a metal rod body and a rubber end, the metal rod body is fixedly connected to the rubber end, the metal rod body is fixedly connected to the permanent magnet plate, and the rubber end is slidably connected to the telescopic hole.

[0013] Preferably, the hydraulic demolding mechanism includes a pouring pipe and a delivery hole. The delivery hole is opened inside the movable mold and connected to the inside of the injection cavity. The liquid guide pipe is arranged outside the movable mold and fixedly connected to the delivery hole for delivering the special demolding agent to the inside of the delivery hole.

[0014] Preferably, an anti-backflow valve is arranged inside the delivery hole to prevent the injection molding colloid from entering the delivery hole, and the anti-backflow valve includes a valve plate, which is arranged at one end of the delivery hole close to the injection cavity, and the end of the valve plate away from the injection cavity is fixedly connected to a valve stem, and the end of the valve stem away from the valve plate is fixedly connected to an inner top plate; the inner top plate is slidably connected to the inside of the delivery hole, and a connecting port is opened on the side of the delivery hole, and the connecting port is located on a side of the inner top plate close to the valve plate, and the liquid guide tube is fixedly connected to the connecting port of the delivery hole.

[0015] Preferably, an extension spring is installed inside one end of the valve plate far from the delivery hole, and the extension spring pushes the inner top plate, and the inner top plate pushes the valve plate to slide toward the injection cavity through the valve stem.

[0016] Preferably, the movable mold is provided with two symmetrical injection cavities, the liquid guide tubes of the two injection cavities are connected, a hydraulic delivery pump is installed at one end of the liquid guide tube away from the delivery hole, a hydraulic sensor is installed at the output end of the hydraulic delivery pump, the telescopic cylinder is a double-axis telescopic cylinder, the two driving shafts of the double-axis telescopic cylinder are respectively fixedly connected to the two ends of the movable mold, a support seat is installed at the bottom of the double-axis telescopic cylinder, and ear plates for installation and connection are fixedly connected at both ends of the support seat.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0018] The semiconductor package injection mold of the present invention realizes the closing and separation of the injection cavity through a double-axis telescopic cylinder, ensures the formation of a sealed cavity, effectively controls the injection pressure, ensures the uniformity of colloid filling and the smoothness of the surface, and the multi-point controllable ejector mechanism realizes multi-point synchronous demolding through a matrix-distributed ejector and rubber end buffer, disperses the demolding force, and reduces damage to the semiconductor package. At the same time, the anti-backflow valve and the electromagnet system ensure the uniform distribution of pressure and the smooth flow of the colloid during the demolding process, thereby improving the demolding efficiency and effect. First, when the mold is closed, the double-axis telescopic cylinder drives the moving mold to move toward the fixed mold to form a sealed injection cavity. Then, the molten colloid is injected into the cavity, the ejector retracts, and the anti-backflow valve is closed to prevent the colloid from leaking. Next, post-curing is carried out, the colloid is cooled and solidified, and at the same time, the hydraulic pump outputs a release agent for demolding.

[0019] During the demolding stage, the electromagnet is energized to generate a magnetic field of the same polarity, which pushes the ejector pins to eject the semiconductor synchronously at multiple points. The demolding force at multiple points is evenly distributed to reduce damage to the package. At this time, the hydraulic pump is started, and the demolding agent is injected into the cavity. The guide groove is used to reduce the adhesion and promote the separation of the colloid. At the same time, the anti-backflow valve is dynamically sealed to prevent colloid contamination and improve the demolding effect and efficiency. After the demolding is completed, the ejector pin reset spring retracts and the anti-backflow valve closes to prepare for the next production cycle. The entire process is automated and efficient, with a significant increase in production capacity and no waste generated, ensuring the high quality and reliability of semiconductor packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the overall external structure of the first embodiment of the present invention;

[0021] Figure 2 It is a schematic cross-sectional structural diagram of a multi-point controllable ejector mechanism according to the first embodiment of the present invention;

[0022] Figure 3 For the present invention Figure 2 A schematic diagram of the enlarged structure at point A;

[0023] Figure 4 It is a schematic structural diagram of a hydraulic demoulding mechanism according to the first embodiment of the present invention;

[0024] Figure 5 For the present invention Figure 4 A schematic diagram of the local enlarged structure at B;

[0025] Figure 6 It is a schematic diagram of the external overall structure of the second embodiment of the present invention;

[0026] Figure 7 It is a schematic diagram of the overall cross-sectional structure of the second embodiment of the present invention.

[0027] Among them: 1. Fixed mold; 2. Moving mold; 3. Support table; 4. Double-axis telescopic cylinder; 5. Injection cavity; 6. Control groove; 7. Ejector pin; 8. Reset spring; 9. Permanent magnet plate; 10. Electromagnet plate; 11. Delivery hole; 12. Liquid guide tube; 15. Valve plate; 16. Valve stem; 17. Inner ejector plate; 18. Extension spring. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1:

[0030] See also Figure 1-5 , the present invention provides a technical solution:

[0031] like Figure 1 As shown, a semiconductor packaging injection mold includes a fixed mold 1 and a movable mold 2. The fixed mold 1 is fixedly connected to a support platform 3 on the side away from the movable mold 2, which is used to fix the mold 1 and withstand the injection pressure; the movable mold 2 is installed with a double-axis telescopic cylinder 4 on the side away from the fixed mold 1, and its two driving shafts are symmetrically connected to the two sides of the movable mold 2 through ear plates to ensure the balance of the closing or separation action. Two injection cavities 5 are symmetrically arranged inside the movable mold 2, and the contour of each injection cavity 5 matches the surface of the chip and lead frame assembly of the semiconductor packaging product to form a sealed cavity.

[0032] like Figure 2 and Figure 3 As shown, a control groove 6 is provided inside the movable mold 2, in which a multi-point controllable ejector mechanism is installed. The ejector mechanism is composed of the following components: an ejector 7, a return spring 8 and a magnetic push component.

[0033] The ejector pins 7 are distributed in a matrix pattern, covering the demoulding force area of ​​the injection cavity 5; the ejector pins 7 are composed of a metal rod body 701 and a rubber end 702. The metal rod body transmits driving force, and the rubber end 702 directly contacts the product surface. When ejecting the packaged semiconductor, the rubber end 702 reduces damage to the semiconductor package.

[0034] One end of the return spring 8 is fixed to the inner wall of the control groove 6, and the other end is connected to the permanent magnet plate 9. The return spring 8 is in a compressed state under normal conditions to push the ejector pin 7 to retract.

[0035] The magnetic pushing assembly includes an electromagnet plate 10 and a permanent magnet plate 9 . The electromagnet plate 10 is fixed to the end of the control slot 6 . The permanent magnet plate 9 is fixedly connected to the metal rod body 701 of the ejector pin 7 and faces the electromagnet plate 10 with the same pole.

[0036] During the injection molding stage: the electromagnet plate 10 is powered off, the reset spring 8 pushes the permanent magnet plate 9 and the ejector pin 7 to retract, and the rubber end 702 is flush with the inner wall of the injection molding cavity 5 to ensure that the injection molding colloid is filled without interference and the surface of the semiconductor package is flat and smooth.

[0037] During the demoulding stage: the electromagnet plate 10 is energized to generate a magnetic field with the same polarity as the permanent magnet plate 9, which pushes the permanent magnet plate 9 to drive the ejector pin 7 to extend toward the injection cavity 5, and ejects the product synchronously at multiple points. The demoulding force is evenly distributed. By controlling the voltage of the electromagnet plate 10, the repulsive force of the electromagnet plate 10 on the permanent magnet plate 9 is adjusted, so that the pressure of the ejector pin on the semiconductor package can be adjusted. Appropriate pressure can ensure that the semiconductor package is ejected while reducing damage to it.

[0038] like Figure 4 and Figure 5 As shown, the hydraulic demoulding mechanism includes: a delivery hole 11, a liquid guide tube 12 and an anti-backflow valve.

[0039] The delivery hole 11 is opened inside the movable mold 2, connecting the injection cavity 5 with the external liquid guide tube 12, and the liquid guide tube 12 is connected with the delivery holes 11 of the two injection cavities. A hydraulic delivery pump and a hydraulic sensor are installed at the end to realize closed-loop control of the release agent flow.

[0040] The anti-backflow valve consists of a valve plate 15, a valve stem 16 and an inner top plate 17. The valve plate 15 is located at one end of the delivery hole 11 close to the injection cavity 5. The inner top plate 17 is connected to the valve plate 15 through the valve stem 16 and is pushed by the extension spring 18 to close the entrance of the delivery hole 11.

[0041] During injection molding and sealing, the injection pressure pushes the valve plate 15 to be close to the entrance of the delivery hole 11 to prevent the colloid from flowing back.

[0042] During demoulding, the demoulding agent is injected, and the hydraulic pump 13 pressurizes and delivers the demoulding agent. The pressure overcomes the preload force of the stretch spring 18, pushes the inner top plate 17 to compress the push spring, and the inner top plate 17 drives the valve plate 15 to shrink inward through the valve stem 16 and enter the delivery hole 11. The delivery hole 11 is provided with guide grooves on both sides of the interior near the injection cavity. When the valve plate 15 enters the delivery hole 11, the demoulding agent flows through the guide grooves of the delivery hole 11 into the interface between the injection cavity 5 and the semiconductor package product, reducing the adhesion force. The hydraulic pressure is generated to push it. Due to the circulation of the demoulding agent, its hydraulic driving force evenly covers the surface of the semiconductor package product, and the driving force is more uniform and stable, which has a good demoulding effect and does not damage the product.

[0043] Combination Figure 1-3 , the workflow of semiconductor packaging injection mold is as follows:

[0044] When the mold is closed, the double-axis telescopic cylinder 4 drives the movable mold 2 to move toward the fixed mold 1, and the injection cavity 5 forms a sealed space after closing.

[0045] Further injection molding, the molten colloid is injected into the cavity, the ejector pin 7 is retracted, and the anti-backflow valve is closed. Then post-curing is carried out, the colloid is cooled and solidified, and the hydraulic sensor monitors the release agent pressure.

[0046] During demoulding, the electromagnet plate 10 is energized, and the ejector pin 7 ejects the product at multiple points; the hydraulic pump 13 is started, and the demoulding agent is injected into the interface to assist separation; the double-axis telescopic cylinder 4 is reset, and the movable mold 2 is separated from the fixed mold 1, completing the demoulding. After further reset, the ejector pin 7 retracts under the action of the reset spring 8, and the anti-backflow valve is closed, preparing for the next cycle.

[0047] The further ejector pin layout is a matrix distribution density of 4×4 / cm 2 , the hardness of the rubber end is Shore A 60-70. The input voltage of the electromagnet control is 24V, the magnetic field strength is ≥0.5T, and the response time is ≤50ms.

[0048] The flow rate of the release agent is 0.2-0.5MPa of the hydraulic pump output pressure, and the single injection volume is 0.1-0.3mL.

[0049] The above scheme generates uniform demoulding force, the matrix ejector is matched with the rubber end buffer, the demoulding force is dispersed to the non-sensitive area of ​​the chip, and the anti-backflow protection is provided. The dynamic sealing design of the valve plate 15 avoids colloid contamination of the hydraulic system, and the production is efficient, the dual injection cavity is molded synchronously, and the production capacity is increased by ≥40% in combination with automatic control. The demoulding agent can be a silicone oil emulsion to form a lubricating film.

[0050] Embodiment 2:

[0051] See also Figure 6-7 , the present invention provides a technical solution:

[0052] The present embodiment provides a semiconductor packaging injection mold for double-sided packaging of semiconductors. The fixed mold 1 and the movable mold 2 adopt exactly the same structural design, and both have independent injection molding, ejection demoulding and hydraulic auxiliary functions. It is suitable for semiconductor products that require double-sided injection molding packaging, such as double-sided heat dissipation substrates or three-dimensional stacked packaging.

[0053] The fixed mold 1 and the movable mold 2 of the semiconductor packaging injection mold are mirror-symmetrical in structure, and both include: a double-axis telescopic cylinder 4, an injection cavity 5 and a multi-point controllable ejector pin 7 mechanism; there are two groups of double-axis telescopic cylinders 4 and they are respectively installed on the outside of the fixed mold 1 and the movable mold 2, and the two are driven to move toward or in the opposite direction through a synchronous control system to ensure mold clamping accuracy and balance.

[0054] Two groups of injection cavities 5 are symmetrically arranged inside each mold, and the cavity contour matches the double-sided structure of the semiconductor product. After the mold is closed, a double-sided sealed cavity is formed, allowing the molten colloid to be injected simultaneously to complete the double-sided packaging. The multi-point controllable ejector pin 7 mechanism is integrated into the control groove 6 inside the mold, and the structure is the same as that of the first embodiment to meet the synchronization requirements of double-sided demoulding.

[0055] The hydraulic demoulding system is independently arranged in the fixed mold 1 and the movable mold 2, including a delivery hole 11, a liquid guide tube 12, an anti-backflow valve and a hydraulic pump, which can inject demoulding agent into the double-sided interface respectively. The cylinders on both sides of the double-axis telescopic cylinder 4 are connected to the central controller through a linkage shaft. When closing the mold, the fixed mold 1 and the movable mold 2 are pushed forward synchronously to ensure that the closing pressure is evenly distributed; when opening the mold, they are separated at a constant speed in the opposite direction to avoid product deviation.

[0056] In addition, a bidirectional injection inlet is arranged at the center axis of the mold, and the molten colloid is evenly distributed to the injection cavity 5 of the fixed mold and the movable mold through the diversion channel, so as to ensure the consistency of the filling rate on both sides.

[0057] Its specific working principle and process:

[0058] First, the double-axis telescopic cylinder 4 drives the fixed mold 1 and the movable mold 2 to move toward each other, and after closing, a double-sided sealed cavity is formed, the ejector 7 is retracted, and the anti-backflow valve is closed. Then the molten colloid is injected into the injection cavity 5 of the fixed mold and the movable mold simultaneously through the two-way injection inlet. During the filling process, the hydraulic sensor monitors the pressure on both sides in real time and dynamically adjusts the injection parameters to maintain balance.

[0059] Furthermore, in the post-curing stage, the colloid is cooled and shaped, and the hydraulic sensors on both sides monitor the pressure of the release agent tank to ensure that the double-sided hydraulic system is in standby state. The electromagnetic iron plate 10 is powered on in advance for preheating to shorten the magnetic field response time. The electromagnetic iron plates 10 on both sides are powered on at the same time, generating a magnetic field of the same polarity to push the permanent magnet plate 9, driving the ejector pin 7 to extend into the cavity, and the double-sided multi-point ejection force acts evenly on the non-sensitive area of ​​the product.

[0060] The hydraulic pumps of the fixed mold and the movable mold are started synchronously, the release agent is injected into the double-sided interface at a certain pressure, and the silicone oil emulsion forms a lubricating film.

[0061] The anti-backflow valve is opened under the action of hydraulic pressure, and the mold release agent covers the surface of the product through the guide groove to reduce the adhesion. The double-axis telescopic cylinder 4 moves in the opposite direction, the fixed mold 1 and the movable mold 2 are separated at the same speed, and the product is taken out by the robot. The ejector pin 7 retracts under the action of the return spring 8, the anti-backflow valve is closed, and the mold release agent pipeline is emptied of the residual liquid to prepare for the next cycle.

[0062] Although specific embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the specific embodiments without departing from the principles and spirit thereof, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A semiconductor packaging injection mold, comprising a fixed mold (1) and a movable mold (2), wherein a side of the fixed mold (1) away from the movable mold (2) is fixedly connected to a support platform (3), and a side of the movable mold (2) away from the fixed mold (1) is installed with a telescopic cylinder, characterized in that: The movable mold (2) is provided with an injection cavity (5) adapted to the shape of the semiconductor, and a multi-point controllable ejector mechanism and a hydraulic demoulding mechanism for stable demoulding are installed inside the movable mold (2).

2. A semiconductor packaging injection mold according to claim 1, characterized in that: The multi-point controllable ejector mechanism comprises an ejector pin (7), a return spring (8) and a magnetic push component. A control groove (6) is provided inside the movable mold (2). The magnetic push component and the return spring (8) are installed inside the control groove (6). A telescopic hole is connected between the control groove (6) and the injection cavity (5). The ejector pin (7) is slidably connected inside the telescopic hole. The magnetic push component pushes the ejector pin (7) to slide from the telescopic hole to the injection cavity (5). The return spring (8) pushes the ejector pin (7) to retract inside the control groove (6).

3. A semiconductor packaging injection mold according to claim 2, characterized in that: A plurality of ejector pins (7) are provided and distributed in a matrix manner inside the injection molding cavity (5).

4. The semiconductor packaging injection mold according to claim 2, characterized in that: The magnetic pushing component comprises an electromagnet plate (10) and a permanent magnet plate (9), wherein the electromagnet plate (10) is fixedly mounted on an end of the control slot (6) away from the telescopic hole, an end of the ejector pin (7) located inside the control slot (6) is fixedly connected to the permanent magnet plate (9), and the permanent magnet plate (9) is slidably connected inside the control slot (6).

5. The semiconductor packaging injection mold according to claim 4, characterized in that: One end of the return spring (8) is fixedly connected to the inner wall of one end of the control slot (6) communicating with the telescopic hole, and the other end is fixedly connected to the permanent magnet plate (9). The return spring (8) pushes the permanent magnet plate (9) toward the electromagnet plate (10).

6. The semiconductor packaging injection mold according to claim 3, characterized in that: The ejector pin (7) comprises a metal rod body and a rubber end, the metal rod body is fixedly connected to the rubber end, the metal rod body is fixedly connected to the permanent magnet plate (9), and the rubber end is slidably connected to the telescopic hole.

7. The semiconductor packaging injection mold according to claim 1, characterized in that: The hydraulic demoulding mechanism comprises a liquid pouring pipe and a delivery hole (11), wherein the delivery hole (11) is opened inside the movable mold (2) and communicated with the inside of the injection cavity (5), and the liquid guide pipe (12) is arranged outside the movable mold (2) and fixedly communicated with the delivery hole (11).

8. The semiconductor packaging injection mold according to claim 7, characterized in that: An anti-backflow valve for preventing the injection molding colloid from entering the delivery hole (11) is arranged inside the delivery hole (11), and the anti-backflow valve comprises a valve plate (15), the valve plate (15) is arranged at one end of the delivery hole (11) close to the injection cavity (5), the end of the valve plate (15) away from the injection cavity (5) is fixedly connected to a valve stem (16), and the end of the valve stem (16) away from the valve plate (15) is fixedly connected to an inner top plate (17); the inner top plate (17) is slidably connected to the inside of the delivery hole (11), a connecting port is opened on the side of the delivery hole (11), and the connecting port is located on a side of the inner top plate (17) close to the valve plate (15), and the liquid guide tube (12) is fixedly connected to the connecting port of the delivery hole (11).

9. The semiconductor packaging injection mold according to claim 8, characterized in that: An extension spring (18) is installed inside one end of the delivery hole (11) far from the valve plate (15), and the extension spring (18) pushes the inner top plate (17). The inner top plate (17) pushes the valve plate (15) to slide toward the injection cavity (5) through the valve stem (16). Guide grooves are provided on both sides of the delivery hole (11) close to the injection cavity (5).

10. The semiconductor packaging injection mold according to claim 9, characterized in that: Two injection cavities (5) are symmetrically arranged inside the movable mold (2). The liquid guide tubes (12) of the two injection cavities (5) are connected to each other. A hydraulic delivery pump is installed at one end of the liquid guide tube (12) away from the delivery hole (11). A hydraulic sensor is installed at the output end of the hydraulic delivery pump. The telescopic cylinder is a double-axis telescopic cylinder (4). The two driving shafts of the double-axis telescopic cylinder (4) are respectively fixedly connected to the two ends of the movable mold (2). A support seat is installed at the bottom of the double-axis telescopic cylinder (4). Ear plates are fixedly connected to the two ends of the support seat.

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