JP2580973B2 - Mold for semiconductor encapsulation and resin encapsulation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for resin-sealing a resin-sealed semiconductor device and a method for resin-sealing a semiconductor device using the mold.

[0002]

2. Description of the Related Art In general, in a resin-sealed semiconductor device, a semiconductor element is held in a cavity of a mold, and the cavity is filled with a resin to perform molding. ing. For example, FIG. 5 is a sectional view of a part of a conventional molding die for performing this resin sealing. As shown, the upper mold 1 and the lower mold 2 are opposed to each other, and a cavity 3 is provided between the upper mold 1 and the lower mold 2. Then, the semiconductor element 10 to be encapsulated is
Then, the TAB tape 11 on which this is mounted is sandwiched between the upper mold 1 and the lower mold 2 and positioned in the cavity 3. Thereafter, although not shown, the sealing resin R is injected from a pot portion separately provided in the mold, and the sealing resin R is filled into the cavity 3 through the gate 5. Then, after a predetermined sealing resin curing time has elapsed, the upper mold 1
The resin sealing step is completed by opening the space between the mold and the lower mold 2 and taking out the semiconductor device including the semiconductor element 10 and the TAB tape 11 whose resin sealing has been completed.

[0003]

In this conventional molding die, as shown in FIG. 6, when the cavity 3 is filled with the sealing resin R, it is held in the cavity 3 due to its viscosity. In some cases, the semiconductor element 10 and the TAB tape 11 are moved to a position deviated from an original position in the cavity 3 in order to drag or push the TAB tape 11. When the filling of the resin is completed in a state where the deformation does not return to its original state and the resin is cured, the semiconductor element 10 and the TAB
The tape 11 is not sealed in a correct position, and molding failure occurs. In fact, it has been found that when such deformation or misalignment occurs in the semiconductor element 10 or the TAB tape 11, the reliability of the semiconductor device is extremely reduced due to disconnection between the two. I have.

For this reason, as shown in the sectional view of FIG. 7, conventionally, a support rod 14 which can be advanced and retracted into the cavity 3 from both the upper mold 1 and the lower mold 2 is provided.
The semiconductor element 10 and the TAB tape 11 held therein are held in place by sandwiching the TAB tape 11 from above and below with the support rods 14,
Then, a configuration in which a resin is filled thereon is adopted. For example,
It is disclosed in Japanese Patent Application Laid-Open No. 1-169936. However, providing the support rods 14 that can move forward and backward in each of the upper and lower molds 1 and 2 complicates the structure of the molds. In particular, one mold is often configured as a fixed mold and the other as a movable mold, but providing a movable rod with this type of support rod also requires a drive mechanism for moving the support rod forward and backward. Therefore, the structure becomes extremely complicated.

Further, in this mold, the support rod 14 is advanced into the cavity 3 until the resin filling the cavity 3 at least surrounds the semiconductor element 10 and the TAB tape 11, and a certain amount of filling is completed. After this, the support rod 14 is retracted. At this time, the flow of the sealing resin R in the cavity 3 is easily disturbed by the support rod 14, and a void is easily generated. These problems have recently become remarkable as semiconductor devices have become thinner, and countermeasures have been desired. SUMMARY OF THE INVENTION An object of the present invention is to provide a molding die for semiconductor encapsulation that prevents displacement of a semiconductor element or the like to be encapsulated with a resin and prevents generation of voids in an encapsulating resin. Another object of the present invention is to provide a resin sealing method capable of preventing a displacement or the like of a semiconductor element or the like and enabling resin sealing without generating a void.

[0006]

According to the present invention, a molding die can be moved into or out of a cavity in one of a pair of dies forming a cavity for resin-sealing and molding a semiconductor element or the like. In addition, a support rod for supporting a semiconductor element or the like at a predetermined position in the cavity when it is advanced, and a gate shutter for opening and closing the gate of one of the molds are provided. In addition, a drive mechanism for independently driving the gate shutter and the support rod is provided, and the support rod is retracted immediately before the gate shutter is opened. Further, it is preferable to provide a cushion at the tip of the support rod which comes into contact with the semiconductor element or the like. In addition, according to the semiconductor resin sealing method of the present invention, a step of arranging a semiconductor element or the like in a cavity formed by a pair of molds and a step of applying a tip of a support rod provided in one of the molds to the semiconductor element or the like. A step of contacting and supporting the semiconductor element and the like; a step of filling the cavity of the mold with a resin from the gate of the other mold; a step of retracting the support rod from the cavity and a gate shutter of one mold. And filling the resin from the gate into the cavity of the mold. For example, when a semiconductor element and a TAB tape on which the semiconductor element is mounted are sealed with a resin, the semiconductor element mounting surface of the TAB tape is placed in a cavity formed by a pair of molds so as to face the other mold. It is preferable to arrange them.

[0007]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a molding die according to Example 1 of the present invention. The upper mold 1 and the lower mold 2 are provided so as to be relatively movable, and the cavity 3 having the same shape as the package shape of the semiconductor device to be resin-molded by the two molds 1 and 2 is formed. In this embodiment, the lower die 2 is configured as a fixed die, and the upper die 1 is configured to be able to move up and down with respect to the lower die 2. Gates 4 and 5 connected to the cavity 3 are opened in each of the molds 1 and 2, respectively. In one of the molds, in this embodiment, the lower mold 2 has a gate for opening and closing its own gate 5. A shutter 6 is provided. Further, a plurality of support rods 7 are provided which can be advanced and retracted into the cavity 3 from the bottom surface of the lower mold 2. The gate shutter 6 and the plurality of support rods 7 are moved up and down by driving mechanisms 8 and 9 including a cam mechanism and a link mechanism, respectively. These drive mechanisms 8 and 9 are configured to operate in synchronization with the operation timing of resin molding, as described later.

The operation of sealing the semiconductor resin using the molding die will be described with reference to FIG. As shown in FIG. 2A, a TAB tape 11 on which a semiconductor element 10 to be resin-sealed is mounted on the lower mold 2 when the upper mold 1 is at the upper movement position. The semiconductor element 10 has a structure in which bumps 12 provided at a plurality of positions are bonded to a circuit pattern (not shown) formed on the lower surface of the TAB tape 11 with the front surface facing upward. Then, by moving the upper mold 1 downward, the TAB tape 11 is held between the two molds 1 and 2,
The semiconductor element 10 and the TAB tape 11 are held at predetermined positions in the cavity 3. At this time, the plurality of support rods 7 have been advanced upward from the lower mold 2, and the tips of the support rods 7 are in contact with the lower surfaces of the semiconductor element 10 and the TAB tape 11. At this time, the gate shutter 6 of the lower mold 2 is closed.

Next, as shown in FIG. 2B, the sealing resin R1 is filled from the gate 4 of the open upper mold 1. Due to its viscosity, the sealing resin R1 flows along the upper surfaces of the TAB tape 11 and the semiconductor element 10, and fills the upper half 3a of the cavity 3. Thereafter, as shown in FIG. 2C, the drive mechanism 8 shown in FIG. 1 is operated to open the gate shutter 6 of the lower mold 2, and the sealing resin R2 is also removed from the gate 5 of the lower mold 2. 3 is filled. At the same time, the support rods 7 are retracted from the inside of the cavity 3 by the drive mechanism 9. Thereby, as shown in FIG. 2D, the sealing resin R2 fills the lower half 3b of the cavity 3 while flowing smoothly. Cavity 3 with sealing resin R2
After a predetermined time elapses after filling the inside of the resin R1, R2
After the resin is cured, the upper mold 1 is moved upward, and the molded resin-encapsulated semiconductor device is removed from the lower mold 2 to complete the resin encapsulation of the semiconductor device.

Therefore, in the first embodiment, the resin R1 is filled in the upper half 3a of the cavity 3 with the semiconductor element 10 to be resin-sealed and the lower side of the TAB tape 11 held by the support rod 7. Depending on the viscosity of the resin R1, the position of the semiconductor element 10 may be shifted,
Problems such as bending of the tape 11 do not occur. After the upper half 3a of the cavity 3 is filled with the resin R1, the lower half 3b is filled with the resin R2. At this time, even if the support rod 7 is retracted from the cavity 3, the semiconductor element 10 and the TAB tape are not filled. 11 is prevented from being displaced or bent by the resin R1 already filled in the upper half 3a of the cavity 3. In addition, when the upper half 3a of the cavity 3 is filled with the resin R1, when the lower half 3b of the cavity 3 is filled with the resin R2, a plurality of the support rods 7 are connected to the lower mold 2 before the resin R2. As a result, the flow of the sealing resin is not disturbed, and no void is generated.

FIG. 3 is a sectional view of a molding die according to a second embodiment of the present invention. In this embodiment, a plurality of support rods 7 which can advance and retreat in the cavity 3 for holding the semiconductor element 10 and the TAB tape 11 are provided in the upper mold 1, and the tip of the support rod 7 is provided with a semiconductor element. In order to protect the surface of the TAB tape 10 and the TAB tape 11, a cushion 13 for cushioning is provided. The cushion 13 is made of a material having heat resistance, such as silicone rubber. In response to this, a gate shutter 6 is provided at the gate 4 of the upper mold 1 so that the gate can be opened and closed. The drive mechanism of the gate shutter 6 and the support rod 7 is not shown.

In this embodiment, as shown in FIG. 4, the lower half 3b of the cavity 3 is first filled with the resin R1. Next, after the lower half 3b is filled with the resin R1,
The gate shutter 6 of the upper mold 1 is opened, and the upper half 3a of the cavity 3 is filled with the resin R2 to complete the resin molding.
At this time, retracting the support bar 7 is the same as in the first embodiment. Therefore, when filling the lower half 3b of the cavity 3 with the resin R1, the displacement of the semiconductor element 10 and the bending of the TAB tape 11 are prevented by the support rod 7, and then the lower half 3b is filled. The upper half 3a can be filled with the resin R2 while preventing the resin R1 from being displaced or bent. Also, the resin R2 is applied to the upper half 3a.
At the time of filling, the support rod 7 is retracted immediately before the filling, so that no void is generated.

In the second embodiment, the support bar 7 is connected to the upper mold 1.
Is preferable when the upper mold 1 is a fixed mold and the lower mold 2 is a movable mold. Also, as shown in FIG.
In the case where the semiconductor element 10 is mounted on the lower surface of the B tape 11, when the lower half 3b is filled with the resin R1, misalignment, bending, and the like are likely to occur due to the corners of the semiconductor element 10. In this case, the configuration of the second embodiment in which the lower half 3b is filled with the resin R1 while being supported by the support rod 7 is preferable. Further, since the cushion 13 is provided at the tip of the support rod 7, the semiconductor element 10
And the impact when contacting the TAB tape 11 can be reduced,
It is also possible to prevent the semiconductor element 10 and the TAB tape 11 from being damaged.

Here, in both the first embodiment and the second embodiment, a slight displacement or bending occurs in the semiconductor element 10 or the TAB tape 11 due to the pressure or viscosity of the resin R2 to be filled last. Although inevitable,
In the second embodiment, the upper half 3a is finally filled with the resin R2, so that the displacement of the semiconductor element 10 and the bending of the TAB tape 11 are mainly lower than the design values. For this reason, TAB
The shoulder of the semiconductor element 10 mounted on the lower surface of the tape 11 and T
It is possible to reduce an edge touch occurrence rate at which the circuit pattern of the AB lead 11 is directly contacted,
The reliability of the semiconductor device can be improved.

Table 1 shows the results of comparative evaluation of the conventional example and the embodiment. The average (n = 100) indicates the deformation (tilt, vertical displacement) of the semiconductor element, and the external void generation rate and the edge touch generation rate of the semiconductor element and the lead on the TAB tape for n = 100.

[Table 1]

[0016]

As described above, according to the present invention, a semiconductor element or the like is supported at a predetermined position in the cavity by one of a pair of molds forming a cavity for sealing a semiconductor element or the like with a resin. Since the support rod and the gate shutter for opening and closing the gate of one of the molds are provided, the semiconductor element and the like can be supported by the support rod when the resin is filled in the cavity, and the position of the semiconductor element and the like can be set. It is possible to prevent displacement, bending, and the like, and increase the reliability of resin sealing. Further, since the gate shutter and the support rod can be operated independently by the drive mechanism, the support rod is retracted immediately before the gate shutter is opened, so that the flow of the resin filled in the cavity is not disturbed. The generation of voids can be prevented. Further, by providing a cushion at the tip of the support rod, an impact when the support rod is brought into contact with the semiconductor element or the like is reduced, thereby preventing the semiconductor element or the like from being deformed or damaged.

Further, while supporting a semiconductor element or the like by a support rod provided in one mold, a resin is filled in a cavity of the other mold, and then the support rod is retracted from the cavity, and then one of the molds is retreated. Since the resin is filled in the cavity of the mold, the misalignment and bending of the semiconductor element and the like are prevented by the support rod at the time of the previous resin filling, and the semiconductor element and the like are prevented by the previously filled resin at the time of the later resin filling. Displacement and bending can be suppressed, and voids can be prevented by retracting the support rod. Furthermore, by arranging the semiconductor element and the TAB tape on which the semiconductor element is mounted in the cavity so that the mounting surface of the semiconductor element of the TAB tape faces the other mold, the semiconductor element is removed from the TAB tape by resin filling later. Can be urged away, T
Edge touch between the AB tape and the semiconductor element can be prevented from occurring.

[Brief description of the drawings]

FIG. 1 is a sectional view of a molding die according to a first embodiment of the present invention.

FIG. 2 is a view for explaining a method of resin sealing a semiconductor device using a molding die of FIG. 1 in the order of steps.

FIG. 3 is a sectional view of a molding die according to a second embodiment of the present invention.

4 is a sectional view of a part of a process of a resin sealing method using a molding die in FIG. 3;

FIG. 5 is a sectional view of a conventional resin-sealed molding die.

FIG. 6 is a cross-sectional view for explaining a problem in a conventional molding die.

FIG. 7 is a cross-sectional view of a conventional improved molding die.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper mold 2 Lower mold 3 Cavity 4,5 Gate 6 Gate shutter 7 Support rod 8,9 Drive mechanism 10 Semiconductor element 11 TAB tape 13 Cushion

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication // B29L 31:34

Claims (5)

(57) [Claims] 1. A cavity is constituted by a pair of molds, a semiconductor element or the like is sandwiched between these molds, and a resin is filled in the cavity through a gate provided in each mold to seal the semiconductor element or the like with a resin. In the mold for semiconductor encapsulation to stop,
A support rod that can move into or out of the cavity in one of the pair of molds, and that supports the semiconductor element or the like at a predetermined position in the cavity when the mold advances, and a gate of one of the molds A molding die for encapsulating a semiconductor, provided with a gate shutter for opening and closing the semiconductor device. 2. The molding die for semiconductor sealing according to claim 1, further comprising a drive mechanism for independently driving the gate shutter and the support rod, and retracting the support rod immediately before opening the gate shutter. . 3. The molding die for semiconductor encapsulation according to claim 1, wherein a cushion is provided at a tip of a support rod abutting on a semiconductor element or the like. 4. A step of arranging a semiconductor element or the like in a cavity formed by a pair of molds, and the step of bringing a tip of a support rod provided in one of the molds into contact with the semiconductor element or the like. Supporting the resin, filling the cavity of the mold with resin from the gate of the other mold, retracting the support rod from the cavity, and opening the gate shutter of the one mold, Filling the cavity of the mold with a resin from a gate. 5. A semiconductor device and a TAB tape on which the semiconductor device is mounted are arranged in a cavity formed by the pair of molds such that a mounting surface of the TAB tape on which the semiconductor device is mounted faces the other mold. Item 5. A resin sealing method for a semiconductor according to Item 4.