A mold flow control structure for reducing the risk of flash

Abstract

The application discloses a die flow control structure for reducing the risk of die flow impact, which comprises a guide arc body arranged on the surface of a substrate between a die glue outlet and a chip for guiding and thinning the die flow, the guide arc body is reversely convex along the direction of the die flow, a part of the die flow can continue to flow downward by jumping over the guide arc body, and the other part is guided by the guide arc body to the outside of both ends of the guide arc body. The guide arc body comprises a guide arc body one arranged between the end head of each column of chips and the die glue outlet, and a part of the die flow is guided by the guide arc body one to the interval between the two adjacent columns of chips. The guide arc body further comprises a guide arc body two arranged in the interval between the two columns of chips, and a part of the die flow entering the interval is guided by the guide arc body two to the two columns of chips on both sides. The die flow flowing to the electric lead wire is thinned, and the impact kinetic energy is weakened, so that the electric lead wire is not easy to be deformed by impact bending.

Description

Technical Field

[0001] This invention relates to a mold flow control structure for reducing the risk of die-offs, and belongs to the field of chip packaging technology. Background Technology

[0002] After the chips on the substrate are wired to their pins (conductive wires), they need to be packaged. Chip packaging involves placing the wire-bonded chip in a special high-temperature mold, injecting molten adhesive, and then cooling it to form a package that covers the chip and all the conductive wires.

[0003] Chip packaging is carried out on a large rectangular substrate with multiple chips arranged in a longitudinal and transverse direction. On one side of the inner wall of the packaging mold, there are multiple injection holes at equal intervals along the length of the rectangular substrate. The glue flowing out of the injection holes forms a mold flow on the substrate from one side to the other.

[0004] The distance between the chip and the pin on the substrate is relatively far, and the wires (electrical conductors) between them are long and arched upwards. During the chip packaging process, sometimes the chip is impacted by the strong flow of molten adhesive, especially when the direction of the flow is close to 90 degrees from the length of the electrical conductor. The electrical conductor between the chip and the pin is easily bent and bent to the adjacent side, causing a short circuit and rendering the entire chip unusable. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to prevent electrical conductors from being subjected to strong current and large-angle impacts during chip packaging.

[0006] To address the above problems, the technical solution proposed by this invention is as follows:

[0007] A mold flow control structure for reducing the risk of mold flow failure includes a flow guide arc body disposed on the substrate surface between the melt outlet and the chip for guiding and thinning the mold flow. The flow guide arc body protrudes in the opposite direction of the mold flow. A portion of the mold flow can cross the flow guide arc body and continue to flow downward, while another portion is guided by the flow guide arc body to both ends of the flow guide arc body.

[0008] The flow guiding arc body includes a flow guiding arc body 1 located between the upper end of each column of chips and the melt outlet, and a portion of the mold flow is guided by the flow guiding arc body 1 to the interval between two adjacent columns of chips.

[0009] Both ends of the current guiding arc body have inner guide leads, and the two inner guide leads are parallel to the wire bonding direction of the wires on both sides of all the wires above the first chip in the corresponding column of chips.

[0010] Below the first flow guide arc body, there is a flat peak arc body that blocks and diverts the excessively high portion of the mold flow that crosses the first flow guide arc body. There is a flow gap between it and the substrate that allows the melt of a set depth to pass through, and the direction of its arc protrusion is opposite to the direction of the mold flow.

[0011] The flat-peak arc body is welded onto the inner guide lead body.

[0012] The flow guiding arc body also includes a second flow guiding arc body located in the interval between the two columns of chips. A portion of the flow entering the interval is guided by the second flow guiding arc body to the two columns of chips on both sides.

[0013] Both ends of the flow guide arc body are provided with external guide leads, which are used to guide a portion of the flow direction of the mold flow of the chips on both sides to be consistent with the wire bonding direction of the electrical wires on the left or right side of the chip 25.

[0014] On both sides of the flow guide arc body, there are flat peak straight bodies respectively, and there is a flow gap between the flat peak straight body and the substrate that allows the melt adhesive of a set depth to pass through.

[0015] The flat-peak straight body is welded onto the outer guide lead body.

[0016] Below the flat-peaked arc body between the two inner guide leads, there is a pillow line that provides padding for the flat-peaked arc body. Beneficial effects

[0017] 1. The current flowing to the conductor is thinned, the impact kinetic energy is weakened, and the conductor is not easily bent or deformed by impact.

[0018] 2. The direction of the mold flow to the conductor is changed so that it is as parallel as possible to the wire-laying direction, avoiding large-angle impact of the mold flow on the conductor and making the conductor more prone to deformation. Attached Figure Description

[0019] Figure 1 This is a top view of the substrate described in Embodiment 1;

[0020] Figure 2 for Figure 1 A partial schematic diagram;

[0021] Figure 3 This is a three-dimensional schematic diagram of the flow-guiding arc body and the inner guide lead body described in Embodiment 1;

[0022] Figure 4 This is a partial top view of the substrate described in Embodiment 2;

[0023] Figure 5 This is a three-dimensional schematic diagram of the flow-guiding arc body and the flat-peak arc body described in Embodiment 2;

[0024] Figure 6This is a partial top view of the substrate described in Embodiment 2, showing a pillow line added under the flat-peaked arc body;

[0025] Figure 7 This is a three-dimensional schematic diagram of the flow guiding arc body and the flat peak arc body described in Embodiment 2. The diagram shows a pillow line added below the flat peak arc body.

[0026] Figure 8 This is a partial top view of the substrate described in Embodiment 3;

[0027] Figure 9 This is a three-dimensional schematic diagram of the flow-guiding arc body 2 and the outer guide lead body described in Embodiment 3;

[0028] Figure 10 This is a partial top view of the substrate described in Embodiment 4;

[0029] Figure 11 This is a three-dimensional schematic diagram of the flow-guiding arc body II, the outer guide lead body, and the flat peak straight body described in Embodiment 4.

[0030] The straight arrows in the attached diagram above indicate the direction of mold flow.

[0031] In the diagram: 1. Guide arc body one; 2. Guide arc body two; 3. Inner guide lead body; 4. Flat peak arc body; 5. Pillow line; 6. Outer guide lead body; 7. Flat peak straight body; 8. Substrate; 9. Interval; 10. Chip; 11. Electrical wire; 12. Molten adhesive outlet. Detailed Implementation

[0032] The present invention will be further described below with reference to embodiments and accompanying drawings:

[0033] It should be noted that the directional terms "up," "down," "left," and "right" used in this article refer only to the orientation of the view. Example 1

[0034] like Figure 1As shown in Figure 3, a flow control structure for reducing the risk of flow obstruction includes a flow-guiding arc body disposed on the surface of a substrate 8 between the melt outlet 12 and the chip 10 for guiding and thinning the flow. The flow-guiding arc body protrudes in the opposite direction to the flow direction, so that part of the flow is guided to the two ends of the flow-guiding arc body, while the other part can cross the flow-guiding arc body and continue to flow downward. In this way, the flow is blocked by the flow-guiding arc body, which firstly reduces some of the flow kinetic energy, thereby reducing the impact force on the electrical wires 11 between the chip 10 and the pins. More importantly, it can guide and separate a part of the flow that has not yet dispersed, so that only a part of it crosses the flow-guiding arc body and continues to flow in the flow direction. This thins the flow towards the chip 10, changes its direction, and reduces the impact force on the electrical wires 11, thereby preventing the electrical wires 11 from being bent or deformed and short-circuiting with adjacent electrical wires 11.

[0035] The aforementioned flow-guiding arc body includes a flow-guiding arc body 1 located between the upper end of each row of chips 10 and the melt outlet 12. A portion of the mold flow is guided by the flow-guiding arc body 11 to the interval 9 between adjacent rows of chips 10. This arrangement mitigates the impact of the melt flowing from the melt outlet 12 on the electrical conductor 11 of the uppermost chip 10 in each row, allowing more melt to enter the interval 9 between adjacent rows of chips 10. Consequently, the melt entering the interval 9 flows in from both sides of each row of chips 10, thus significantly reducing the frontal impact of the mold flow on the uppermost chip 10 in each row.

[0036] Both ends of the current-guiding arc body 1 have inner guide leads 3. The two inner guide leads 3 are parallel to the wiring direction of the wires 11 on both sides of all the wires 11 above the first chip 10 in the corresponding column of chips 10 (see...). Figure 2 As shown), in this way, the direction of the mold flow over the guide arc body 1 to the upper part of the first chip 10 in a row of chips 10 is basically consistent with the direction of the wire 11 being wired, so as to avoid the wire 11 being impacted by the mold flow at too large an angle, causing lateral impact on the wire 11.

[0037] The aforementioned flow guide arc body is fixed on the substrate 8 by welding. Example 2

[0038] like Figure 4As shown in Figure 7, this is a further improvement of Embodiment 1. Below the flow-guiding arc body 1, a flat-peak arc body 4 is provided to block and divert the excessively high portion of the mold flow that crosses the flow-guiding arc body 1. It has a flow gap between itself and the substrate 8 that allows a set depth of molten adhesive to pass through, and its arc protrusion direction is opposite to the mold flow direction. This further ensures that the mold flow flowing in from the top of a row of chips 10 is controlled at a set depth, and that mold flow exceeding this set depth is guided into the interval 9 between two adjacent rows of chips 10.

[0039] The flat-peak arc body 4 is welded onto the inner guide lead body 3, so that the flat-peak arc body 4, the inner guide lead body 3 and the guide arc body 1 can be connected into a whole, so that they can be welded onto the substrate 8 in one go, improving work efficiency.

[0040] Below the flat-peaked arc body 4 between the two inner guide leads 3, there is a pillow line 5 that cushions the flat-peaked arc body 4. At the same time, the pillow line 5 can also be set as a guide line. Example 3

[0041] like Figure 8 , 9 As shown, the difference from the above embodiment is that the flow guiding arc body also includes a second flow guiding arc body 2 disposed in the interval 9 between the two rows of chips 10. A portion of the flow entering the interval 9 is guided by the second flow guiding arc body 2 to the two rows of chips 10 on both sides, while the other portion of the flow entering the interval 9 continues to flow downward. External guide leads 6 are provided at both ends of the second flow guiding arc body 2 to align the flow direction of a portion of the flow guiding the chips 10 on both sides with the wire bonding direction of the electrical conductors 11 on the left or right side of the chip 25, thereby preventing the electrical conductors 11 on both sides of the chip 10 from being impacted by the flow at a large angle. Example 4

[0042] like Figure 10 , 11 As shown, this is a further improvement of Embodiment 3. Flat-peak straight bodies 7 are respectively provided on both sides of the flow guiding arc body 2. The flat-peak straight body 7 and the substrate 8 have a flow gap that allows the set depth of molten adhesive to pass through, thus further ensuring that the depth of the adhesive entering the chip 10 from both sides is within the set range.

[0043] The flat-peak straight body 7 is welded onto the outer guide lead body 6, thereby connecting all the flow guiding arc bodies 2 and their outer guide lead body 6 and flat-peak straight body 7 in the interval 9 into one unit, so as to improve their welding efficiency on the substrate 8.

[0044] The above embodiments are only used to describe the present invention more clearly, and should not be regarded as limiting the scope of protection covered by the present invention. Any equivalent modifications should be regarded as falling within the scope of protection covered by the present invention.

Claims

1. A mold flow control structure for reducing the risk of failure, characterized in that: Includes a flow guide arc body provided on the surface of the substrate (8) between the melt outlet (12) and the chip (10) for dividing and thinning the mold flow. The flow guide arc body protrudes in the opposite direction of the mold flow. Part of the mold flow can cross the flow guide arc body and continue to flow downward, while the other part is divided by the flow guide arc body to the two ends of the flow guide arc body. The flow guiding arc body includes a flow guiding arc body one (1) located between the upper end of each column of chips (10) and the melt outlet (12). A portion of the mold flow is guided by the flow guiding arc body one (1) to the interval (9) between two adjacent columns of chips (10). Both ends of the flow guiding arc body one (1) have inner guide leads (3). The two inner guide leads (3) are parallel to the wire bonding direction of the wires (11) on both sides of all the wires (11) above the first upper chip (10) in the corresponding column of chips (10). Below the flow guiding arc body one (1), there is a flat peak arc body (4) that blocks and guides the excessively high portion of the mold flow that crosses the flow guiding arc body one (1). There is a flow gap between it and the substrate (8) that allows the melt of a set depth to pass through. Its arc protrusion direction is opposite to the mold flow.

2. The mold flow control structure for reducing the risk of failure according to claim 1, characterized in that: The flat-peak arc body (4) is welded onto the inner guide lead body (3).

3. The mold flow control structure for reducing the risk of failure according to claim 1, characterized in that: The flow guide arc body also includes a flow guide arc body two (2) located in the interval (9) between the two columns of chips (10). A portion of the flow entering the interval (9) is guided by the flow guide arc body two (2) to the two columns of chips (10) on both sides respectively.

4. The die flow control structure for reducing the risk of die failure according to claim 3, characterized in that: Both ends of the flow-guiding arc body (2) are provided with external guide lead bodies (6) to guide a portion of the flow direction of the mold flow of the chips (10) on both sides to be consistent with the wire bonding direction of the electrical wires (11) on the left or right side of the chip.

5. The die flow control structure for reducing the risk of die failure according to claim 4, characterized in that: On both sides of the flow guide arc body (2), there are flat peak straight bodies (7), and there is a flow gap between the flat peak straight body (7) and the substrate (8) that allows the set depth of melt to pass through.

6. The die flow control structure for reducing the risk of die failure according to claim 5, characterized in that: The flat-peak straight body (7) is welded onto the outer guide lead body (6).

7. The die flow control structure for reducing the risk of die failure according to claim 2, characterized in that: Below the flat-peak arc body (4) between the two inner guide leads (3), there is a pillow line (5) that cushions the flat-peak arc body (4).

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