JPH05329891A - Mold for sealing lead frame with resin - Google Patents

Abstract

PURPOSE:To obtain a mold used for sealing a lead frame with a resin while preventing the damage of the lead frame by a cured residual resin and efficiently removing a resin adhering to the peripheral edge of the resin-sealed lead frame. CONSTITUTION:In a mold 12 for sealing a lead frame 16 with a resin, the lead frame 16 is set in a recessed part 10 formed in a parting surface 14, and a specific part 20 of the lead frame 16 is sealed with a resin. In this mold 12, a resin reservoir part 18 is provided. The resin reservoir part 18 is recessed in the parting surface 14 to be connected to the recessed part 10. The cross sectional area of the resin reservoir part 18 is equal from the bottom to the open end thereof, or gradually increased from the bottom to the open end thereof.

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 encapsulation of a lead frame. More specifically, the lead frame is set in a recess formed in a parting surface, and a specific portion of the lead frame is resin-sealed. The present invention relates to a resin mold for a lead frame.

[0002]

2. Description of the Related Art One example of a conventional resin-sealing mold for a lead frame is shown in FIG. 4 (a partial plan view of a lower mold) and FIG. .. On the upper surface (parting surface) 102 of the lower mold 100, a shallow recess 106 for setting a resin-sealed lead frame 104 is set.
Are formed. The lead frame 104 is set in the concave portion 106, the upper mold 108 is closed (state of FIG. 5),
By filling the cavity 112 with the molten resin from the gate 110, the periphery of the semiconductor chip 114 can be resin-sealed. The lower mold 100 and the upper mold 108 are firmly closed so that the molten resin does not enter the parts other than the cavity 112, but there is a tolerance in the lead frame 104, and the recess 1
The lead frame 104, which is slightly smaller than the size of 06, may be set in the recess 106. In that case, a gap 11 is formed between the recess 106 and the lead frame 104.
6 is formed around the lead frame 104.
Further, since the gate (or runner) 110 for introducing the molten resin into the cavity 112 is formed in the upper mold 108 in a direction crossing the gap 116, the gate 110 and the gap 116 communicate with each other. When the molten resin is filled in the cavity 112 in this communication state, a part of the molten resin penetrates into the gap 116 from the gate 110.

When the molten resin enters the gap 116, the solidified resin adheres to the peripheral edge of the lead frame 104 released from the mold after the completion of molding. Therefore, it is necessary to remove the resin adhered to the entire peripheral edge in a later step. Occurs. In particular, the adhered resin is thin and adheres to the entire periphery, so that the removal work is troublesome. Therefore, in the conventional resin sealing die of the lead frame, the lower die 100 is provided with a resin reservoir 118 for accumulating the molten resin that has entered the gap 116. The resin reservoir 118 is formed outside the recess 106, and is formed in a hole capable of storing the molten resin that has entered the gap 116 during resin sealing. The gap 116 and the resin reservoir 118 are formed to have a volume filled with one resin sealing. Further, since the bottom portion of the resin reservoir 118 is formed to have a larger vertical cross-sectional area than the top portion thereof, even if the resin 120 solidified in the resin reservoir 118 is connected to the lead frame 104, the lead frame 104 is not formed. Since the resin cannot be removed from the resin reservoir 118 when it is released, it is peeled from the lead frame 104. Therefore, it is possible to take out the lead frame 104 having no resin adhered to the periphery.

[0004]

However, the above-mentioned conventional mold for resin encapsulation of the lead frame has the following problems. When resin sealing is performed once, the cured resin 120 remaining in the gap 116 and the resin reservoir 118 is in the same state as a part of the lower mold 100. The resin sealing is repeated in this state. However, when the size of the lead frame 104 to be sealed exceeds the tolerance, the cured resin 120 in the gap 116 is crushed, and the resin is then sealed. The lead frame 104 may be damaged. In addition, the cured resin 120 in the gap 116 may be damaged and remain on the parting surface of the lower die 100, which may also damage the next lead frame 104. Further, since the vertical cross-sectional area of the resin reservoir 118 is larger at the bottom than at the top, the resin 120 in the resin reservoir 118 is surely attached to the lead frame 104 when the lead frame 104 is released from the mold after completion of molding. Although it can be peeled off from the resin 104, the resin 1
Since the resin 20 is accumulated, it is necessary to remove the resin 120 remaining in the resin reservoir 118 after performing the resin sealing a predetermined number of times. However, the resin reservoir 118 has a shape such that the resin 120 remaining inside cannot be removed, as described above. Therefore, in order to remove the resin 120, the portion 122 of the lower mold 100 is removed to remove the resin reservoir. Since the resin 120 in 118 must be removed, there is a problem that this removing work is troublesome. Accordingly, the present invention provides a resin molding die for a lead frame, which can prevent the lead frame from being damaged by the cured residual resin and can efficiently remove the resin attached to the periphery of the resin-sealed lead frame. The purpose is to do.

[0005]

In order to solve the above problems, the present invention has the following constitution. That is, a lead frame is set in a recess formed in a parting surface, and a resin molding die for a lead frame for resin-sealing a specific portion of the lead frame is provided with a recess in the parting surface. It is characterized in that it is provided with a resin reservoir portion which is connected to the concave portion and has a sectional area which is equal from the innermost portion to the opening portion or which has a sectional area which gradually increases from the innermost portion to the opening portion.

[0006]

[Operation] The operation will be described. The resin reservoir is recessed in the parting surface of the mold and communicates with the recess, and the cross-sectional area is the same from the innermost part to the opening, or the cross-sectional area gradually increases from the innermost part to the opening. Since the resin has a large shape, the resin cured in the gap and the resin reservoir can be taken out integrally with the lead frame when the lead frame is released. At this time, since the resin is concentrated and solidified in a portion corresponding to the resin reservoir, there are few portions to be removed, and since the resin has a certain degree of rigidity, it is easier to remove than a thin resin. Further, even if the solidified resin remains in the resin reservoir, it is possible to take out and remove the mold without disassembling it.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a partial plan view of a lower mold forming a resin-sealing mold for a lead frame of this embodiment,
FIG. 2 shows a cross-sectional view near the portion A in FIG. 1 when the mold is closed. First, in FIG. 1, 10 is a recess,
Upper surface (parting surface) 14 of the lower mold 12 that constitutes the mold
Is recessed in. The depth of the recess 10 is the same as the designed thickness of the lead frame 16 to be set. The length and width of the recess 10 are also formed to have the same size as the designed size of the lead frame 16. Reference numeral 18 denotes a resin reservoir, which is recessed in the parting surface 14.
The resin reservoir 18 is provided on both ends of the recess 10 and communicates with the recess 10. The cross-sectional shape of the resin reservoir 18 is formed such that the vertical cross-sectional area gradually increases from the innermost portion toward the opening, as shown in FIG. The cross-sectional shape of the resin reservoir 18 may be such that the cross-sectional area in the vertical direction gradually increases from the innermost portion to the opening, or the cross-sectional area in the vertical direction is the same from the innermost portion to the opening. Good. Further, the capacity of the resin reservoir 18 is set to be substantially the same as the amount of the molten resin known empirically when it flows into the gap described later in a single resin sealing.

A method of using the mold having the resin reservoir 18 will be described. The lead frame 16 to be resin-sealed is set in the recess 10 of the lower die 12. When the lead frame 16 is set in the recess 10, each semiconductor chip 20, which is a specific portion, corresponds to a cavity 22 (see FIG. 2) formed when the mold is closed. Due to the allowable tolerances in the size of the lead frame 16, the lead frame 16 does not necessarily fit within the recess 10 and the recess 1
A gap 24 often occurs between the inner wall surface of the lead frame 16 and the outer wall surface of the lead frame 16. In this state, lower mold 12 and upper mold 2
6 and 6 are closed (state of FIG. 2), and the molten resin is runner 28.
And is filled into the cavity 22 through the gate 30. In this embodiment, the runner 28 and the gate 30 are formed on the lower surface (parting surface) of the upper mold 26 (or the lower mold 12) and cross the gap 24.

Most of the filled molten resin is sent into the cavity 22 through the gate 30, and the semiconductor chip 2
0 and the like are resin-sealed. However, the molten resin that has entered the gap 24 from the runner 28 or the gate 30 flows in the gap 24 and is accumulated in the resin reservoir 18. When the filling of the molten resin is completed and the resin is solidified, the resin sealing portion 36 (see FIG.
(See) is molded. Thereafter, the lower mold 12 and the upper mold 26 are opened, and the lead frame 16 resin-sealed with eject pins (not shown) is released from the lower mold 12. At this time, since the resin reservoir 18 is connected to the recess 10, the resin accumulated in the resin reservoir 18 and the lead frame 16 are connected to each other. Attempt to pull out of the part 18. Resin reservoir 1
8 has a cross-sectional area that gradually increases from the innermost portion toward the opening, so that the remaining resin remains in the lead frame 1
Release from the mold together with 6. The state is shown in FIG.

As shown in FIG. 3, the resin 34 solidified in the resin reservoir 18 is the outer edge of the lead frame 16,
The resin is concentrated and solidified in a portion corresponding to the resin reservoir portion 18 (two portions in this embodiment). Therefore, even when the resin 34 is removed, the number of places to be removed can be small. Further, since the resin 34 is intensively solidified, it has rigidity and can be easily separated from the lead frame 16 simply by bending or hitting. It is much easier to remove than the conventional thin resin, and the workability can be improved. Further, since the resin reservoir 18 has a cross-sectional area that gradually increases from the innermost portion toward the opening, it solidifies in the resin reservoir 18 when the lead frame 16 is released from the mold after completion of molding. Even if the resin 34 remains, it can be easily taken out and removed without disassembling the lower mold 12. The various preferred embodiments of the present invention have been described above.
The present invention is not limited to the above-mentioned embodiments, and many modifications can be made without departing from the spirit of the invention, for example, the position and number of the resin reservoir 18 can be set arbitrarily. Of course.

[0011]

EFFECTS OF THE INVENTION When the mold for resin encapsulation of the lead frame according to the present invention is used, the resin reservoir is recessed in the parting surface of the mold, communicates with the recess, and has the deepest cross-sectional area. From the innermost part to the opening part, or because the cross-sectional area gradually increases from the innermost part toward the opening part, the resin cured in the gap and the resin reservoir part can be separated from the leadframe when releasing the leadframe. It becomes possible to take it out as one. At this time, since the resin is concentrated and solidified in a portion corresponding to the resin reservoir, there are few portions to be removed, and since the resin has a certain degree of rigidity, it is easier to remove than a thin resin. Further, even if the solidified resin remains in the resin reservoir, it can be taken out and removed without disassembling the mold, so that the resin adhered to the periphery of the resin-sealed lead frame and remains in the resin reservoir. It has a remarkable effect that the resin can be removed reliably and efficiently.

[Brief description of drawings]

FIG. 1 is a partial plan view of a lower die forming a resin-sealing die of a lead frame in an embodiment of a resin-sealing die of a lead frame according to the present invention.

FIG. 2 is a cross-sectional view showing a portion A in FIG. 1 in a mold closed state.

FIG. 3 is a partial front view of a lead frame which is resin-molded and released.

FIG. 4 is a partial plan view of a lower mold forming a resin-molding mold of a conventional lead frame.

5 is a cross-sectional view of the vicinity of the X part of FIG. 4 in a mold closed state.

[Explanation of symbols]

 10 concave part 12 lower mold 14 parting surface 16 lead frame 18 resin reservoir 24 gap 26 upper mold 34 resin

Claims (1)

[Claims] 1. A mold for resin encapsulation of a lead frame, wherein a lead frame is set in a recess formed in a parting surface, and a specific portion of the lead frame is resin-sealed. In addition, the resin reservoir is characterized in that it has a cross-sectional area equal to that from the innermost portion to the opening portion, or has a resin reservoir portion whose cross-sectional area gradually increases from the innermost portion to the opening portion while communicating with the recess. Mold for resin encapsulation of lead frame.