JPH10150135A - Lead frame, resin molding method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To completely remove resin from a runner after a resin sealing operation is carried out so as to prevent a resin molding device from shutting down or malfunctioning after a resin sealing operation is carried out, by a method wherein a resin tablet insertion hole is provided between prescribed lead component parts, and at least a hole is provided to each of regions which extend each from the tablet insertion hole to the corner of each of the lead component part regions. SOLUTION: A circular resin tablet insertion hole 6 where a resin tablet is inserted is provided between lead component parts 2 arranged on a plate-like member 1a in its width direction. Holes 7a to 7c are provided to a region which extends from the insertion hole 6 to some corner of the lead component part 2 arranged in the width direction. A suspension pin 8 extends outwards from some corner of a chip mount 3 to be linked to the outer periphery of the lead component part 2. That, is, the resin tablet insertion hole 6 and the holes 7a to 7c of the same shape with a punch are provided so as to remove a lump of resin composed of rivet-like runner resin and cull resin by the punch through holes formed by a die in a resin sealing process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame on which a semiconductor element is mounted, a resin molding method for sealing a semiconductor element mounted on the lead frame with a resin and removing unnecessary portions and resin burrs of the lead frame, and an apparatus therefor. About.

[0002]

2. Description of the Related Art In the assembly process after manufacturing a semiconductor chip in the manufacture of a semiconductor device, a semiconductor chip is mounted on a lead frame, wired with a thin metal wire by a wire bonding device, and then sealed with a resin. Assembly was completed. However, the outer body of the semiconductor device that has just been resin-sealed is a component of the lead frame, but a tie bar or a suspension pin that is unnecessary as a semiconductor device protrudes, or a resin flash generated after resin sealing is formed. It remains attached around the body. Therefore,
The resin molding apparatus is provided with a mold for finishing such removal.

FIGS. 7A and 7B are a plan view and a sectional view showing an example of a conventional resin sealing mold. Conventionally, resin sealing of a semiconductor chip has been performed using a mold shown in FIG. In order to resin seal the semiconductor chip 32 mounted on the lead frame 30 with this mold, first, the lead frame 30 is placed on the lower mold 25 and the resin tablet 31 is put into the pot 23.

Next, the upper mold 24 and the lower mold 25 are closed, the mold is clamped, and the molten resin tablet 31 is pushed by a plunger (not shown) to flow the molten resin into the runner 22 through the cull portion 26 and from the runner 22 through the gate. The molten resin is injected into the cavity 21. The molten resin filled in the cavity 21 wraps and seals a structure including the semiconductor chip 32 and the mounting surface of the lead frame 30 and the tie bars and leads. Then, the molten resin is cured by the heat of the mold, and the outer body of the semiconductor device is formed.

FIG. 8 is a sectional view showing a resin molding state of a lead frame after resin sealing. As shown in FIG. 8, the resin molding state of the lead frame taken out of the mold by the above-described resin sealing is formed by the resin outer body 33 formed by resin-sealing the semiconductor chip and the cull part of the mold. The cull resin 34 and the runner resin 35 formed by the runner are attached to the lead frame 30.

FIGS. 9 (a) and 9 (b) are cross-sectional views for explaining a method of removing resin burrs adhering to a lead frame after resin sealing. Thus, the lead frame 3
Resin burrs such as the runner resin 35 and the cull resin 34 adhering to 0 had to be removed first for a later process. Conventionally, in order to remove the resin burrs, a mold for removal is prepared, the resin outer body 33 shown in FIG. 8 is held by a mold die, and the cull resin 34 is beaten with a punch to punch the cull resin 34. And the runner resin 35 at the same time
It was more detached and removed. However, with an impact of simply tapping the cull resin 34, the cull resin 34 can be released, but the runner resin 35 does not come off.
Often, as shown in FIG.
5 remains attached to the lead frame 30.

In such a case, the runner resin 35 falls into the mechanism of the transfer system of the automated line due to vibration or the like during the transfer of the lead frame, and the runner resin enters the transfer mechanism and stops the transfer line. Problem was happening.

As a method for simultaneously and smoothly removing the cull resin 34 and the runner resin 35, Japanese Utility Model Application Laid-Open No. 5-76046.
No. 6,086,045. This method uses the cull resin 34
A stage supported by the cradle, supporting the resin outer body 33 and capable of rotating, and a plunger for pushing the resin outer body 33 downward are provided, and the resin outer body is pushed by the plunger and inclined outward to a predetermined angle, It is characterized in that the runner resin 35 and the lead frame 30 are detached from each other, and furthermore, the lead frame 30 is folded and removed at the connection between the resin outer body 33 and the runner resin 35.

FIGS. 10A and 10B are a cross-sectional view and a plan view of a lower die for explaining a tie bar cutting die for a lead frame in a conventional example. After the cull resin and the runner resin are removed, the lead frame is sent to a tie bar cutting mold. Then, as shown in FIG. 10, it is placed on the lower mold 27b through the transport rail 28. The resin outer body 33 of the lead frame 30 is the lower mold 2
When entering the escape portion 7b, the upper die 27a descends, and the punch 29 enters the escape portion 27c to cut the tie bar of the lead frame 30. At this time, the resin flash (usually called a resin dam) surrounded by the tie bar and the lead is also removed.

The resin frame of the lead frame from which the tie bar has been cut is sent to the next step of cutting and bending the lead while being supported by the lead frame main body by the suspension pin 37, and the periphery of the resin frame of the lead frame is removed. Is cut into an appropriate length, and the cut lead is bent and formed into a desired shape. And
In the final stage, the hanging pins 37 of FIG. 10 were cut by a mold, and the finishing process was completed, thus completing the assembly of the semiconductor device.

[0011]

In the resin sealing method and the finishing step described above, since the runner resin and the cull resin are removed by punch impact, as shown in FIG. When the removal failure occurs, FIG.
The runner resin is caught on the transfer rail 28 in the tie bar cutting die of No. 0, and the device stops. For this reason, there is a problem that not only a large number of man-hours are required for returning the apparatus, but also the downtime is long and the operation rate is reduced.

Also, in the method of bending and removing the root of the runner resin, a small amount of the gate residue 35b often remains, as shown in FIG. 10B. Although such a small resin burr does not catch on the transport rail in the tie bar cutting device, the small resin burr is used by the small resin burr when the resin outer body is clamped and fixed to the tie bar cutting mold at the time of cutting the tie bar. Of the blade will be damaged. If at least one blade edge of the lower die is damaged, the entire lower die must be re-created, resulting in a high repair cost.

After the step using the resin sealing mold, the resin burr removing step, the tie bar cutting and removing step, the lead cutting and bending forming step, the plating step and the hanging pin cutting and removing step, and the mold and the transport mechanism are arranged side by side. There is a disadvantage that the floor area is large and the floor area cannot be used efficiently.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to completely remove a runner resin after resin encapsulation and to eliminate a stop or failure of the device after resin encapsulation, to effectively use a resin molding method and a floor area. It is to provide a device that can be used.

[0015]

A first feature of the present invention is as follows.
A square mounting surface portion on which the semiconductor chip is mounted, a plurality of leads extending from the outer periphery of the mounting surface portion and connecting to the outer peripheral portion surrounding the mounting surface portion, and intersecting these leads, A quadrangular region between the tie bar portion to be connected and the lead portion derived from the mounting surface portion, and extending outward from the mounting surface portion and including a plurality of suspension pin portions connected to the outer peripheral portion. In a long plate-shaped lead frame formed by arranging a plurality of lead components in two rows, a circular hole into which a resin tablet is inserted between the lead components arranged in the short direction and a short direction. A lead frame in which at least one hole is formed in a region connecting any of the corners of the respective regions of the lead component body arranged in a circle and the circular hole. Further, it is desirable that the circular hole is connected to the hole.

A second feature of the present invention resides in that a resin is injected into a space surrounding the semiconductor chip mounted on the mounting surface of the lead frame and is sealed with the resin. A resin molding method of forming a resin mass that penetrates a hole with the resin and fixes the front and back surfaces of the lead frame in a rivet shape. Preferably, the method further includes a step of punching out the resin block by piercing the circular hole and the hole with a punch. Further, it is preferable that the tie bar portion is cut and removed simultaneously with the cutting and removing of the tie bar portion or the hanging pin portion.

A third feature of the present invention is that a first cavity forming a cavity surrounding the semiconductor chip is formed.
Upper mold in which a hollow of the lead frame is formed with the circular hole of the lead frame and a second shallow cavity facing the hole, a pot portion into which the resin tablet is inserted, and a runner through which molten resin flows from the pot portion A resin molding apparatus, comprising: a lower mold in which a third cavity forming the cavity is formed by the first cavity of the upper mold. Further, the resin molding device, an upper die having a first punch that penetrates the circular hole and the hole and knocks down the resin mass.
It is desirable to provide a mold for removing resin burrs, comprising: a lower mold having a die having an escape hole into which the resin mass is inserted, on which the lead frame according to claim 1 is mounted. Further, in the mold for removing resin burrs of the resin molding apparatus, an upper mold including a second punch for cutting and removing the tie bar portion or the hanging pin portion in addition to the first punch, and the lead frame. It is desirable to provide a tie bar portion or a suspension pin portion including a die having a die having an escape hole into which the resin mass and the second punch are inserted, and a mold for removing resin burrs.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing a lead frame for explaining a first embodiment of the present invention. As shown in FIG. 1, the lead frame has a long plate-like member 1a.
A plurality of lead portions 5 extending from the outer periphery of the mounting surface portion 3 and connecting to an outer peripheral portion surrounding the mounting surface portion 3, and a plurality of lead portions 5; A plurality of lead components 2 each of which is a quadrangular region constituted by a tie bar portion 4 intersecting with the lead portion 5 and connecting the lead portions 5 are formed in the plate-shaped member 1a in two rows.

A circular resin tablet insertion hole 6 into which a resin tablet described later is inserted between the lead components arranged in the short direction of the plate-like member 1a and the lead components 2 arranged in the short direction. Holes 7 a and 7 are provided in the region connecting any corner of each region and the resin tablet charging hole 6.
b, 7c are formed. The suspension pins 8 extend outward from the corners of the mounting surface 2 and are connected to the outer periphery of the lead component 2.

That is, as will be described later, this lead frame is formed by punching a resin lump formed of a rivet-shaped runner portion resin and a cull portion resin through a hole formed by a mold at the time of resin sealing. A hole 6 and holes 7a, 7 of a resin tablet having the same shape as the punch so that the punch is inserted.
b, 7c. Also, the holes 7a, 7b and 7c from which the resin mass formed in the runner portion is pulled out may be one hole similar to the shape of the runner portion.

FIG. 2 is a view showing a modification of the lead frame shown in FIG. As shown in FIG. 2, the lead frame has a long hole 7 d connected to the resin tablet charging hole 6 and extending to the corner region of the lead component 2. Otherwise, it is the same as the lead frame of FIG. The use of this lead frame has the advantage that the resin block can be more securely fixed to the lead frame as compared with the above-described lead frame, and can be removed with a single punch formed by the resin tablet charging hole 6 and the long hole 7d. .

In the above-described lead frame, one resin tablet insertion hole 6 is provided between the two lead components arranged in the short direction, but the area of the four lead components 2 arranged in the short and long directions is formed. One resin tablet charging hole 6 may be provided at the center. In this case, the holes 7a,
The holes 7b and 7c or the holes 7d in FIG. 2 are formed in the corner regions near the resin tablet insertion holes 6 of the adjacent lead components 2 and the regions connected to the resin tablet insertion holes 6.

FIGS. 3A and 3B are a plan view of a lower mold and a cross-sectional view of the resin mold for explaining the resin mold according to the second embodiment of the present invention. As shown in FIG. 3, the mold for mounting the semiconductor chip on the lead frame having the above-mentioned resin tablet insertion hole and the hole and sealing the resin with the resin chip includes a recess forming the cavity 21 and a resin tablet insertion hole of the lead frame 1. 6 and holes 7a, 7b,
The upper die 24 having the shallow dents 9 and the depressions 9a opposed to 7c, the pot 23 into which the resin tablet 31 is inserted, the runner 10 through which the molten resin flows, and the depressions of the upper die 24. And a lower mold 25 in which a recess forming the cavity 21 into which the molten resin is injected is formed.

In order to seal the lead frame 1 shown in FIG.
First, as shown in FIG. 3A, the lead frame 1 is positioned on the lower mold 25, and the resin tablet 31 is put into the pot 23 through the resin tablet insertion hole 6 of the lead frame 1.

Next, as shown in FIG. 3B, the mold is clamped, and the resin tablet 31 is melted by the heat of the mold.
Then, the molten resin flows from the pot 23 to the runner 10 by raising the plunger (not shown), and the molten resin is injected into the cavity 21 from the runner 10 by raising the plunger. When the cavity 21 is filled with the molten resin, the curing of the molten resin is started, and the molten resin is completely solidified soon.

FIGS. 4A and 4B are a plan view and a sectional view of a lead frame showing a state after resin sealing.
As described above, the lead frame 1 in which the semiconductor chip is sealed with the resin is provided at the center of the lead frame 1 between the resin outer bodies 33 in which the semiconductor chip is formed with the resin as shown in FIG. A cull resin 34a is formed, and a cull resin 35a formed by a mold runner adheres to the lead frame 1 between the cull resin 34a and the resin outer body 33. Further, the runner resin 35a and the cull resin 34a are both fixed in the form of rivets through holes formed in advance in the lead frame 1, and conventionally, the resin is removed without removing the lead frame during transportation. Can be sent to the mold.

FIGS. 5A and 5B are a plan view and a partial sectional view of a die showing a mold for removing resin burrs according to a third embodiment of the present invention. As shown in FIG. 5, the mold for removing the runner resin and the cull resin of the lead frame to which the resin has adhered can be moved up and down by the guide of the guide post 43 and the resin tablet insertion hole of the lead frame 1 can be removed. An upper die 29 having a punch 41 for knocking down the through-hole resin 34a and punches 40a, 40b and 40c for knocking down the runner resin 35a through the holes in the lead frame 1, and the resin outer body 3 of the lead frame 1.
And a lower die 42 for fixing the die 27 having a recess 26 formed therein for receiving the third resin 3 and an escape hole 28 formed in a large hole so that the cull resin 34a and the runner resin 35a do not come into contact with each other.

Next, the operation of removing the runner resin 35a and the cull resin 34a shown in FIG. 4 by the resin flash removing mold will be described. First, the lead frame 1 sent from the resin sealing mold by the handler is mounted on the die 27 of the lower mold 42. Then, the upper mold 29 descends, and the punch 4
At the same time as hitting the cull resin 34a with 1, the punches 40a, 4
0b and 40c hit the runner resin 35a, so that the runner resin 35a and the cull resin 34a
As 6, it is pushed down below the lower mold 42.

As described above, the lead frame 1 from which the runner resin 35a and the cull resin 34a of the lead frame 1 are removed is sent to a tie bar cutting die, and the tie bar portion 4 shown in FIG. 4 is cut. Then, after the lead portion 4 is plated with solder, the lead frame 1 is bent and separated from the lead frame, and finally the suspension pin portion 8 is cut and the semiconductor device having the resin outer body is separated from the lead frame. It is.

FIGS. 6 (a) and 6 (b) are a plan view of a die and a die AA sectional view showing the die and a die of a die for removing resin burrs according to a fourth embodiment of the present invention. It is sectional drawing of the metal mold | die containing. In the above-described embodiment, the resin burrs after the resin sealing are independently removed.
In this embodiment, resin burrs and tie bars are removed simultaneously.

As shown in FIG. 6, the mold for removing the resin burr and the tie bar includes punches 41, 4 for knocking down a resin burr made of a cull resin 34a and a runner resin 35a.
A tie bar punch 44 for cutting the tie bar and the tie bar 0a, 40b and 40c is embedded, and a pad 4 for holding each tip of the punch and sliding each punch.
7, a mounting surface 51 on which the resin outer body 33 is inserted and mounted, a tie bar punch escape hole 46 into which the tie bar punch 44 enters, and an escape hole 50 for the cull resin 34a and the runner resin 35a. A lower die 49 having a die 45 is provided.

Next, the operation of removing the tie bar and the resin burrs by this mold will be described. First, the lead frame 1 sent from the resin sealing mold is attached to the die 45 of the lower mold 49.
Is placed on the surface. At this time, the resin outer body 33 of the lead frame 1 is placed on the mounting surface 51 in the depression. Next, the upper die 48 descends, and the pad 47 presses the flat portion (the portion where the resin is not attached) of the lead frame 1. further,
Punches 41 and 40 are released from pads 47 by lowering upper mold 48.
a, 40b, and 40c protrude and drop the cull resin 34a and the runner resin 35a downward as a protruding resin piece 36. At the same time, the tie bar punch protrudes and cuts the tie bar portion 4 of FIG. Drop. At this time, the resin flash between the tie bar portion and the mounting surface portion 3 in FIG. 1 is also removed together with the tie bar piece 4a.

As described above, by removing the resin burrs at the same time as the removal of the tie bars, one step of the resin burrs removing step can be omitted, the lead frame transfer line between the steps can be shortened, and the equipment cost can be reduced. There is an advantage that the flow is also reduced. After removing the resin burrs and tie bars from the lead frame, bending the leads and plating the leads with solder, cutting the suspension pins, separating the resin outer shell from the lead frame, and assembling the semiconductor device. Complete.

The removal of the resin burr may be performed simultaneously with the cutting of the suspension pin portion 8 in FIG. In this case, a punch for cutting the suspension pin 8 is buried in the upper die 29 of FIG.
It is sufficient to provide relief holes for punches for hanging pin cutting at the two corners of the remaining recesses 26 other than the above.

[0036]

As described above, according to the present invention, a hole is preliminarily formed in a required place of a lead frame,
When sealing a semiconductor chip mounted on a lead frame with a resin, the molten resin flows into the hole and is formed into a resin block that is fixed in a rivet shape so as to straddle the front and back surfaces of the lead frame. After that, the resin block is surely removed with a punch and then transferred to the subsequent process.Therefore, there is no failure of the transfer mechanism due to the lack of the resin block, and no damage to the tie-bar cutting mold. This has the effect of preventing the rate from decreasing and improving the production capacity of the line.

Further, by removing the resin block at the same time as the removal of the tie bar or the hanging pin, at least one step can be omitted, the space for the resin sealing and molding apparatus can be reduced, and the floor area can be used effectively. This also has the effect of reducing equipment costs.

[Brief description of the drawings]

FIG. 1 is a plan view showing a lead frame for explaining a first embodiment of the present invention.

FIG. 2 is a view showing a modification of the lead frame of FIG. 1;

FIG. 3 is a plan view of a lower mold and a cross-sectional view of the resin-sealing mold for describing a resin-sealing mold according to a second embodiment of the present invention.

FIG. 4 is a plan view and a cross-sectional view of the lead frame showing a state after resin sealing.

FIG. 5 is a plan view and a partial cross-sectional view of a die showing a mold for removing resin burrs according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a die including a die for removing a tie bar and a resin burr according to a fourth embodiment of the present invention, a die showing the die, and an AA cross-sectional view of the die.

FIG. 7 is a plan view and a sectional view showing an example of a conventional resin-sealing mold.

FIG. 8 is a sectional view showing a resin molding state of a lead frame after resin sealing.

FIG. 9 is a cross-sectional view for explaining a method of removing a resin flash attached to a lead frame after resin sealing.

FIG. 10 is a cross-sectional view and a plan view of a lower die for explaining a tie-bar cutting die for a lead frame in a conventional example.

[Explanation of symbols]

 1, 30 Lead frame 1a Plate member 2 Lead structure 3 Mounting surface 4 Tie bar 4a Tie bar piece 5 Lead 6 Resin tablet insertion hole 7a, 7b, 7c, 7d hole 8 Hanging pin 9, 26 Cull 9a Recess 10,22 Runner 21 Cavity 23 Pot 24,27a, 29,48 Upper die 25,27b, 42,49 Lower die 26 Depression 27,45 Die 27c Escape part 28,50 Escape hole 31 Resin tablet 32 Semiconductor chip 33 Resin shell Body 34, 34a Cull part resin 35, 35a Runner part resin 35b Remaining gate 36 Resin piece 37 Hanging pin 40a, 40b, 40c, 41 Punch 43 Guide post 44 Tie bar punch 46 Tie bar punch escape hole 47 Pad 51 Placement surface

Claims (8)

[Claims] A plurality of lead portions extending from the outer periphery of the mounting surface portion and connecting to an outer peripheral portion surrounding the mounting surface portion and intersecting the lead portions; A square formed between a tie bar portion connecting the lead portion and the lead portion derived from the mounting surface portion and extending outward from the mounting surface portion and connected to the outer peripheral portion; In a long plate-shaped lead frame formed by arranging a plurality of lead components in a shape region in two rows, a circular shape in which a resin tablet is inserted between the lead components arranged in a short direction. A lead frame, wherein at least one hole is formed in a region connecting any one of the corners of each of the lead component parts arranged in the short direction with the hole and the circular hole. 2. The lead frame according to claim 1, wherein the circular hole is connected to the hole. 3. A resin is injected into a space surrounding a periphery of the semiconductor chip mounted on the mounting surface of the lead frame according to claim 1, and is sealed with the resin. A resin mass which penetrates the lead frame with the resin and fixes the front and back surfaces of the lead frame in a rivet shape. 4. The resin molding method according to claim 3, further comprising a step of punching through the circular hole and the hole with a punch and knocking down the resin block. 5. The resin molding method according to claim 3, wherein said tie bar portion is cut and removed simultaneously with said cutting and removing of said tie bar portion or said hanging pin portion. 6. The semiconductor device according to claim 1, further comprising a first recess forming a cavity which is the space surrounding the semiconductor chip.
An upper die in which the circular hole of the lead frame and a second shallow depression facing the hole are formed, a pot portion into which the resin tablet is inserted, and a runner through which molten resin flows from the pot portion. A resin molding apparatus, comprising: a lower mold in which the first hollow of the upper mold and a third hollow forming the cavity are formed. 7. An upper mold comprising: the circular hole; and a first punch penetrating through the hole and knocking down the resin mass.
7. A resin flash removing mold comprising: a lower mold having a die having an escape hole into which the lead lump is inserted while the lead frame according to claim 1 is placed. Resin molding equipment. 8. The mold for removing resin burrs according to claim 7, further comprising: a second punch for cutting and removing the tie bar portion or the hanging pin portion in addition to the first punch; A tie bar portion or a suspension pin portion, comprising a die having a die having a relief hole into which the lead lump and the second punch are inserted while the lead frame according to claim 1 is placed, and a metal for removing resin flash. The resin molding apparatus according to claim 6, wherein a mold is provided.