JP2841926B2 - Resin sealing device for integrated circuits - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin sealing device for an integrated circuit.

[0002]

2. Description of the Related Art A resin sealing method for an integrated circuit using a conventional resin sealing apparatus will be described with reference to FIG. First, as shown in FIG. 3A, a lead in which a semiconductor element 5 is fixed to an island 2 of a lead frame 1 with an adhesive 6 and an inner lead 3 is electrically connected to the semiconductor element 5 by a thin metal wire 4. The upper mold 8 in which the temperature of the frame 1 is raised to about 140 to 180 ° C.
A and the lower mold 8B are loaded so as to be sandwiched between them, and preheated. Further, the island 2 and the semiconductor element 5 before the resin sealing are heated by heat conduction through the lead frame 1 and the inner leads 3 as shown in FIG. Next, the resin tablet 10 for sealing is inserted into the pot 14 provided in the lower mold 8B, and the plunger 9 is raised and pressurized. Start melting from the part where it is.

As shown in FIG. 3C, the molten fluid resin 10A flows into the upper and lower cavities 13A and 13B through the runner 11 and the gate 12, and is finally completely filled. The molten resin 10 melted at this time
Since A is a thermosetting type, it cures after a certain time. Further, the upper die 8A and the lower die 8B are opened up and down, and the upper and lower mold cavities 13A and 13B are separated from the resin-sealed integrated circuit by pushing the surface of the cured sealing resin 10B with the push-up pins 7A. Is done.

[0004]

However, in the resin sealing method for an integrated circuit using the above-described conventional resin sealing device,
As shown in FIGS. 3A and 3B, the lead frame 1
Is the surface temperature of the upper mold 8A and the lower mold 8B of about 140 to 180 ° C.
Directly heated. The island 2 and the semiconductor element 5 are indirectly heated in a hollow cavity. Therefore, the temperatures at the point D of the semiconductor element 5 and the point C of the lead frame 1 after the preheating and sealing are as shown in FIG. 4, and the temperature difference ΔT is large. Therefore, a warp (mechanical strain) Δd proportional to the coefficient of thermal expansion α and the length 1 due to the material of the lead frame 1 is generated as shown in FIG.

Further, as the lead frame 1, a copper alloy having a thermal expansion coefficient α of about 16 × 10 ^-6 1 / ° C., which is about four times as large as that of the 42 alloy, is recommended in terms of heat conduction and price. Δd tends to increase. Further, recent integrated circuits have a large number of pins and a large number of pins, and the number of pins is 100 to 3 as well.
Because of the 00 pins, deformation and disconnection of the thin metal wire 4 are likely to occur. Further, the area of the semiconductor element 5 is increased to about 100 to 200 mm ² ,
Due to the warp Δd, a mechanical stress is applied to the semiconductor element 5 and cracks and the like are easily generated.

Further, if the island 2 is sealed with resin while keeping its warp Δd, the outer shape of the sealing resin 10B is warped, and external terminals (not shown) are deformed, causing problems such as poor coplanarity. Due to the warp Δd of the island 2, the resin balance of the fluid resin is deteriorated, and there is a problem that stable molding conditions are not obtained and defects such as voids occur. Furthermore, since the tip of the sealing resin 16 that has not been completely cured is pushed by the push-up pin 7A having a small area, a large mechanical stress is applied to the inside, and a crack or the like may be generated in the semiconductor element 5.

[0007]

According to the present invention, there is provided an integrated circuit resin sealing apparatus comprising: an upper mold having an upper mold cavity provided on a lower surface; a runner, a gate, a lower mold cavity provided on an upper surface; And a lower die having a push-up pin provided to be vertically movable through the cavity, wherein the push-up pin is formed in such a size that its upper surface is in contact with the entire lower surface of the island of the lead frame. Is what is being done.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIGS. 1A and 1B are cross-sectional views of an embodiment of the present invention, particularly showing the order of the resin sealing steps.

In FIG. 1A, an upper die 8A is the same as the conventional one, and an upper die cavity 13A is provided on the lower surface thereof. A runner 11, a gate 12, and a lower mold cavity 13B are provided on the surface of the lower mold 8B. In particular, the push-up pin 7 piercing through the center of the lower mold cavity 13B and vertically movable is formed in such a size that its upper surface is in contact with the entire lower surface of the island 2 of the lead frame 1. This will be further described below together with the resin sealing method.

A semiconductor element 5 is applied on the island 2 with an adhesive 6
The lead frame 1 in which the semiconductor element 5 and the inner lead 3 are electrically connected by the thin metal wire 4 is
As shown in (a), the push-up pin 7 of the lower mold 13B is projected at a position where the lower mold 13B comes into surface contact with the island 2 so that about 140 to 1
Place on each surface which was preheated to 80 ° C. and heated. Upper die 8A, which is heated to about 140-180 ° C
Then load it so as to sandwich it. At this time lead frame 1
And the island 2 and the semiconductor element 5 are heated substantially uniformly, so that the temperatures at the point A of the lead frame and the point B of the semiconductor element are as shown in FIG. 2, and the temperature difference ΔT can be reduced. Therefore, the warpage of the lead frame 1 is also reduced. Next, after lowering the push-up pin 7 protruding before resin sealing to the bottom of the lower mold cavity 13B, the resin tablet 10 is inserted into the pot 14 provided in the lower mold 8B.

Next, as shown in FIG. 1B, when the plunger 9 is raised and pressurized, the resin tablet 10
The melting is started from the portion in contact with the lower mold 8B by the heat of 40 to 180 ° C. Further, the melted fluid resin 10A passes through the runner 11 and the gate 12 to form the lower mold cavity 13.
B and is finally completely filled. In this case, since the warp (mechanical strain) of the island 2 is small, the flow resin 10A
And the molding conditions become stable. In addition, the cured sealing resin 10B can be easily separated from the lower mold cavity 13B so that the tip is pushed up by the push-up pin 7 having a large area so that no mechanical stress is applied to the inside.

[0012]

As described above, according to the present invention, the island is directly heated by the push-up pin by forming the upper surface of the lower push-up pin so as to be in contact with the entire lower surface of the island. Since the temperature difference between the island and the semiconductor element is reduced, the warpage of the lead frame or the island is also reduced. Therefore, there is an effect that deformation and disconnection in the thin metal wire can be prevented and cracks generated in the semiconductor element can be prevented. Further, there is an effect that deformation and disconnection of the thin metal wire due to vibration when setting the lead frame in the resin sealing mold can be prevented.

Further, since the warpage of the island is reduced and the flowing resin flows stably, void defects can be reduced, and the warp of the outer shape of the resin seal is reduced, and the coplanarity of the external terminals is improved. Furthermore, when separating the sealing resin that has not been completely cured from the cavity, the separation resin is pressed while the surface of the sealing resin is pressed with a push-up pin having a much larger area than before, so that the mechanical stress due to the push-up pin is reduced. . Therefore, there is also an effect that a crack or the like of the semiconductor element can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of one embodiment of the present invention.

FIG. 2 is a diagram showing a rise in temperature of a lead frame and a semiconductor element according to an embodiment.

FIG. 3 is a cross-sectional view of a conventional resin sealing device.

FIG. 4 is a diagram showing a rise in temperature of a lead frame and a semiconductor element by a conventional resin sealing device.

[Description of Signs] 1 Lead frame 2 Island 3 Inner lead 4 Thin metal wire 5 Semiconductor element 6 Adhesive 7, 7A Push-up pin 8A Upper die 8B Lower die 9 Plunger 10 Resin tablet 10A Flowing resin 10B Sealing resin 11 Runner 12 Gate 13A Upper mold cavity 13B Lower mold cavity 14 Pot

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/56 H01L 23/28-23/30

Claims (1)

(57) [Claims] An upper mold having an upper mold cavity provided on a lower surface, a runner, a gate, a lower mold cavity provided on an upper surface, and a push-up pin provided to be vertically movable through the lower mold cavity. A resin sealing device for an integrated circuit comprising a lower die, wherein the push-up pin is formed in a size such that an upper surface thereof is in contact with the entire lower surface of the island of the lead frame.