Semiconductor plastic package mold

Abstract

The utility model provides a semiconductor plastic package mold, and relates to the technical field of semiconductor plastic package. The die comprises an upper die and a lower die, an upper cavity and a lower cavity are respectively arranged at the bottom of the upper die and the top of the lower die, the lower die is provided with an air pipe communicated with the inside of the lower die, the air pipe is communicated with a vacuum pipe and a delivery pipe, the vacuum pipe and the delivery pipe are both provided with valves, the vacuum pipe is communicated with a vacuum system, and the delivery pipe is provided with valves. And the conveying pipe is communicated with a nitrogen source. According to the utility model, through vacuumizing, the injection molding material filling efficiency is improved, the injection molding time is shortened, and the semiconductor packaging efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor molding technology, specifically to a semiconductor molding mold. Background Technology

[0002] Semiconductors are materials whose conductivity at room temperature falls between that of conductors and insulators. The conductivity of semiconductor materials can be altered by doping. The concentration and polarity of impurities incorporated into an intrinsic semiconductor significantly affect its conductivity. Semiconductors doped with donor impurities primarily exhibit electron-type conductivity in the conduction band, while semiconductors doped with acceptor impurities exhibit hole-type conductivity.

[0003] Semiconductor packaging refers to the process of processing tested wafers into individual chips according to product model and functional requirements. The packaging process is as follows: the wafer from the front-end wafer process is diced into small chips, and then the diced chips are glued onto the islands of the corresponding substrate (lead frame). Then, ultra-fine metal (gold, tin, copper, aluminum) wires or conductive resin are used to connect the bonding pads of the chip to the corresponding pins of the substrate to form the required circuit. Then, the individual chips are encapsulated and protected with plastic shells. After encapsulation, a series of operations are performed. After packaging, finished product testing is carried out, which usually goes through processes such as incoming inspection, testing, and packaging, and finally, the chips are stored and shipped.

[0004] Molding is a crucial process in semiconductor packaging. In existing technologies, the semiconductor and lead frame that have completed wire bonding are placed in a mold, and then a molding compound is injected to encapsulate the gold wires on the wafer and lead frame, protecting the components from damage, preventing gas oxidation of the internal chip, and ensuring the safety and stability of the product. During injection molding, the process is relatively long due to the limited flowability of the injection molding compound. If the injection molding compound can fill the mold cavity as quickly as possible, reducing the injection molding time, the efficiency of semiconductor packaging can be improved. Utility Model Content

[0005] The purpose of this invention is to develop a semiconductor molding die that improves the filling efficiency of injection molding materials, reduces injection molding time, and improves semiconductor packaging efficiency by using vacuum extraction.

[0006] This utility model is achieved through the following technical solution:

[0007] A semiconductor molding die, comprising:

[0008] Upper mold and lower mold;

[0009] The upper cavity and the lower cavity are respectively located at the bottom of the upper mold and the top of the lower mold;

[0010] The lower mold is provided with an air pipe that communicates with its interior. The air pipe is connected to a vacuum pipe and a delivery pipe. Both the vacuum pipe and the delivery pipe are equipped with valves. The vacuum pipe is connected to a vacuum system, and the delivery pipe is connected to a nitrogen source.

[0011] Optionally, the top edge of the lower mold is provided with a flange that mates with the outer wall of the upper mold. The upper mold descends and its outer wall slides into contact with the inner wall of the flange. The air pipe is located on the flange.

[0012] Optionally, the lower part of the inner wall of the flange is vertical, and the upper part of the inner wall of the flange is inclined, with the upper part of the inner wall of the flange inclined outward from bottom to top.

[0013] Optionally, the outer wall of the upper mold is provided with a plurality of sealing rings that mate with the inner wall of the flange.

[0014] Optionally, the inner edge of the sealing ring is connected to the outer wall of the upper mold, the cross-section of the sealing ring is arranged at an angle, the outer edge of the sealing ring is inclined upward, and the outer edge of the sealing ring is higher than its inner edge.

[0015] Optionally, the outer edge of the sealing ring is covered with a number of tooth-shaped sealing teeth, which are arranged in a closed ring along the outer edge of the sealing ring, and the sealing ring below the area where the sealing teeth are arranged is arc-shaped.

[0016] Optionally, a flow channel system is provided between the upper mold and the lower mold, the flow channel system including an upper flow channel at the bottom of the upper mold and a lower flow channel at the top of the lower mold.

[0017] Optionally, the upper mold is provided with a material hole that extends through to the upper flow channel, and an injection tube is provided inside the material hole.

[0018] Optionally, multiple circulation pipes are provided in the upper mold inside the upper flow channel and the lower mold inside the lower flow channel, and heat transfer oil is provided in the flow channels of the circulation pipes.

[0019] Optionally, the circulation pipelines are arranged at equal intervals.

[0020] The beneficial effects of this utility model are:

[0021] Before semiconductor molding, this invention can evacuate the molding cavity, so that the injection molding process is carried out in an environment with a certain degree of vacuum. This avoids the presence of air in the molding cavity, which not only avoids the possible presence of air bubbles in the molding body and reduces voids in the molding body, but also avoids the oxidation of the lead frame / chip surface caused by oxygen. It can also reduce the flow resistance of the injection molding material, reduce the injection molding filling time, and improve the efficiency of the molding operation. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a structural diagram of the present utility model;

[0024] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0025] Reference numerals: 1. Lower mold; 2. Upper mold; 3. Sealing ring; 4. Upper cavity; 5. Lower cavity; 6. Flange; 7. Air pipe; 8. Vacuum pipe; 9. Conveying pipe; 10. Lower runner; 11. Upper runner; 12. Material hole; 13. Injection tube. Detailed Implementation

[0026] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0028] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0029] like Figure 1 and Figure 2 As shown, this utility model discloses a semiconductor molding die, including a lower mold 1 and an upper mold 2. The lower mold 1 has two lower cavities 5 at its top and the upper mold 2 has two upper cavities 4 at its bottom. After the lower mold 1 and the upper mold 2 are closed, the two upper cavities 4 and the two lower cavities 5 respectively form molding cavities.

[0030] The upper mold 2 between the two upper cavities 4 is provided with a vertically arranged material hole 12. The material hole 12 is matched with the injection tube 13 of the injection molding machine. The injection tube 13 can be inserted into the material hole 12 for injection molding.

[0031] A flow channel system is provided between the upper mold 2 and the lower mold 1 to cooperate with the molding cavity. The flow channel system includes an upper flow channel 11 located at the bottom of the upper mold 2 and a lower flow channel 10 located at the top of the lower mold 1. The upper flow channel 11 is located between the two upper cavities 4, and the bottom end of the material hole 12 extends through the upper flow channel 11. The lower flow channel 10 is located between the two lower cavities 5. After the upper mold 2 and the lower mold 1 are closed, there is a gap between the upper flow channel 11 and the lower flow channel 10 for the flow of injection plastic. Multiple circulation pipes are provided in the upper mold 2 inside the upper flow channel 11 and in the lower mold 1 inside the lower flow channel 10. The circulation pipes are arranged at equal intervals and heat transfer oil is introduced into the circulation pipes. The heat transfer oil can control the temperature rise of the upper flow channel 11 and the lower flow channel 10. During injection molding, the high-temperature heat transfer oil is introduced into the circulation pipes to raise the temperature of the upper flow channel 11 and the lower flow channel 10, so that the injection plastic entering through the injection pipe 13 maintains good fluidity and improves injection molding efficiency.

[0032] The lower mold 1 has a flange 6 around its top edge. The lower part of the inner wall of the flange 6 is vertical, while the upper part of the inner wall of the flange 6 is inclined at a very small angle, and the upper part of the inner wall of the flange 6 is inclined outward from bottom to top. The outer wall of the upper mold 2 fits with the flange 6. When the upper mold 2 and the lower mold 1 are closed, the outer wall of the upper mold 2 slides and contacts the inner wall of the flange 6 to seal.

[0033] Two air pipes 7 are provided on the lower part of the outer wall of flange 6. The two air pipes 7 are symmetrically arranged and located on the sides of the two lower cavities 5 respectively. The air pipes 7 are connected to the inner side of flange 6. Vacuum pipe 8 and delivery pipe 9 are connected to the air pipes 7. Vacuum pipe 8 and delivery pipe 9 are both equipped with valves. Vacuum pipe 8 is connected to a vacuum system and can be used to evacuate air pipes 7 and the inner side of flange 6. Delivery pipe 9 is connected to a nitrogen source and can be used to break the vacuum and inject nitrogen into the inner area of ​​flange 6.

[0034] The outer wall of the upper mold 2 is provided with three sealing rings 3 that mate with the inner wall of the flange 6, filling the gap between the outer wall of the upper mold 2 and the flange 6. The inner edge of the sealing ring 3 is connected to the outer wall of the upper mold 2, and the cross-section of the sealing ring 3 is arranged at an angle. The outer edge of the sealing ring 3 is inclined upward, and the outer edge of the sealing ring 3 is higher than its inner edge. The outer edge of the sealing ring 3 is covered with a number of tooth-like sealing teeth, which are arranged in a closed ring along the outer edge of the sealing ring 3. The sealing ring 3 below the area where the sealing teeth are arranged is arc-shaped.

[0035] When the upper mold 2 and the lower mold 1 are closed, the outer wall of the upper mold 2 first slides into the inner side of the flange 6 of the lower mold 1. The outer wall of the upper mold 2 and the inner wall of the flange 6 slide in contact, and the sealing ring 3 contacts the inner wall of the flange 6. During the downward movement of the upper mold 2, the arc-shaped area at the bottom of the sealing ring 3 contacts and seals the inner wall of the flange 6. When the bottom of the upper mold 2 is close to the lower mold 1 and the outer wall of the upper mold 2 does not seal the air pipe 7, the vacuum pipe 8 performs vacuuming. The air in the cavity between the upper mold 2 and the lower mold 1 is drawn and tends to a vacuum state. The upper mold 2 and the lower mold 1 maintain a vacuum state and the upper mold 2 continues to descend until it closes on the lower mold 1. The lower area of ​​the sealing ring 3 is in a vacuum state, and the external air pressure is on the upper part of the sealing ring 3. The sealing ring 3 has a tendency to swing downward, so that the lower part and the outer edge of the sealing ring 3 are tightly attached to the inner wall of the flange 6 to maintain a seal.

[0036] Before semiconductor molding, this invention can evacuate the molding cavity, so that the injection molding process is carried out in an environment with a certain degree of vacuum. This avoids the presence of air in the molding cavity, which not only avoids the possible presence of air bubbles in the molding body and reduces voids in the molding body, but also avoids the oxidation of the lead frame / chip surface caused by oxygen. It can also reduce the flow resistance of the injection molding material, reduce the injection molding filling time, and improve the efficiency of the molding operation.

[0037] The above embodiments are merely preferred embodiments of this utility model and are not intended to limit the technical solutions of this utility model. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of this utility model patent.

Claims

1. A semiconductor molding compound, characterized in that, include: Upper mold and lower mold; The upper cavity and the lower cavity are respectively located at the bottom of the upper mold and the top of the lower mold; The lower mold is provided with an air pipe that communicates with its interior. The air pipe is connected to a vacuum pipe and a delivery pipe. Both the vacuum pipe and the delivery pipe are equipped with valves. The vacuum pipe is connected to a vacuum system, and the delivery pipe is connected to a nitrogen source.

2. The semiconductor molding die according to claim 1, characterized in that, The lower mold has a flange at its top edge that mates with the outer wall of the upper mold. When the upper mold descends, its outer wall slides into contact with the inner wall of the flange. The air pipe is located on the flange.

3. The semiconductor molding die according to claim 2, characterized in that, The lower part of the inner wall of the flange is vertical, and the upper part of the inner wall of the flange is inclined, with the upper part of the inner wall of the flange inclined outward from bottom to top.

4. The semiconductor molding die according to claim 2, characterized in that, The outer wall of the upper mold is provided with multiple sealing rings that mate with the inner wall of the flange.

5. The semiconductor molding die according to claim 4, characterized in that, The inner edge of the sealing ring is connected to the outer wall of the upper mold. The cross-section of the sealing ring is arranged at an angle, and the outer edge of the sealing ring is inclined upward, with the outer edge of the sealing ring being higher than its inner edge.

6. The semiconductor molding die according to claim 5, characterized in that, The outer edge of the sealing ring is covered with a number of tooth-shaped sealing teeth, which are arranged in a closed ring along the outer edge of the sealing ring. The sealing ring below the area where the sealing teeth are arranged is arc-shaped.

7. The semiconductor molding die according to any one of claims 1 to 6, characterized in that, A flow channel system is provided between the upper mold and the lower mold, the flow channel system including an upper flow channel at the bottom of the upper mold and a lower flow channel at the top of the lower mold.

8. The semiconductor molding die according to claim 7, characterized in that, The upper mold is provided with a material hole that extends through to the upper flow channel, and an injection tube is provided inside the material hole.

9. The semiconductor molding die according to claim 8, characterized in that, Multiple circulation pipes are provided in the upper mold inside the upper flow channel and the lower mold inside the lower flow channel, and heat transfer oil is flowed in the circulation pipes.

10. The semiconductor molding die according to claim 9, characterized in that, The circulation pipelines are arranged at equal intervals.

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