JPH11340401A - Semiconductor device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the heat radiating property of a semiconductor device, while the degradation of the moisture resistance and external appearance of its resin encapsulant is prevented. SOLUTION: At the molding of a resin encopsulant 25, the bottom face of a tab 16 is exposed on the bottom face of the encapsulant, by pressing the tab 16 against the bottom of a cavity by pushing a heat radiating plate 15 connected to the tab 16 by pushing a section which protrudes from the cavity. On the outer periphery of the encapsulant 25, the impression 40A of the pushing section is left. Since the bottom face of the tab 16 is exposed on the bottom face of the encapsulant 25, the heat radiating ability of a semiconductor device is improved. Since the mark 40A is located far from the tab 16, the degradation in the moisture resistance property of a pellet and the external appearance of the resin encapsulant 25 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing technique, and more particularly to a technique for improving the heat radiation performance of a resin-sealed package. For example, the present invention relates to a semiconductor integrated circuit device having a surface-mount type resin-sealed package. Hereinafter, it is referred to as an IC.

[0002]

2. Description of the Related Art An IC provided with a surface-mount type resin-sealed package includes a semiconductor pellet (hereinafter, referred to as a pellet), a tab to which the pellet is bonded, and
A plurality of inner leads electrically connected to each bonding pad of the pellet via a bonding wire, outer leads respectively connected to each inner lead, and a resin for sealing the pellet, tab and each inner lead. And a sealing body. As a means for improving the heat radiation performance in an IC provided with this surface-mount type resin-sealed package, a main surface (hereinafter, referred to as a lower surface) of the tab opposite to the pellet-bonding main surface from the lower surface of the resin-sealed body. Exposure is generally considered. However, when the lower surface of the tab is exposed at the lower surface of the resin sealing body, a part of the resin of the resin sealing body goes around to the lower surface of the tab, so that poor sealing or poor appearance occurs and the yield is reduced. There is a problem that it decreases.

Japanese Patent Application Laid-Open No. Hei 5-291449 discloses a method in which a fixing portion is projected from a tab, and a resin projection is formed by pressing a projection projecting from a cavity into the fixing portion during molding of a resin sealing body. There has been proposed a technique for preventing a resin for molding a sealing body from flowing around a lower surface of a tab.

[0004]

However, in the above-described method of manufacturing a semiconductor device, since the mark of the projection that has pressed the fixing portion of the tab remains as a hole in the resin sealing body, the moisture resistance of the resin sealing body is reduced. There is a problem that appearance performance is reduced.

An object of the present invention is to provide a technique for manufacturing a semiconductor device capable of improving the heat radiation performance while preventing the moisture resistance and the appearance performance of a resin sealing body from deteriorating.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0007]

The outline of a typical invention among the inventions disclosed in the present application is as follows.

That is, in molding the resin sealing body, the tab connecting member connected to the tab is pressed by the pressing portion projecting from the cavity to press the tab against the bottom surface of the cavity, so that the lower surface of the tab is sealed with the resin. It is characterized in that it is exposed on the lower surface of the stop.

According to the above-described means, since the lower surface of the tab is exposed at the lower surface of the resin sealing body, the heat radiation performance of the semiconductor device is improved. In addition, since the pressing portion is located far away from the tab by being located in the tab connecting member, it is possible to prevent a decrease in moisture resistance to the semiconductor pellet and a decrease in appearance performance of the resin sealing body.

[0010]

FIG. 1 shows a semiconductor device according to an embodiment of the present invention, and FIG. 2 et seq. Show respective steps in a manufacturing method thereof.

In the present embodiment, the semiconductor device according to the present invention is provided with a surface-mount type resin-sealed package.
C, a resin-encapsulated SOP / IC (Small
Outline Package IC. Hereafter, SOP
・ It is called IC. ). SOP ・ IC
Reference numeral 28 denotes a pellet 22, a tab 16 to which the pellet 22 is bonded, a radiator plate 15 as a connecting member connected to the tab 16, and each bonding pad 22 a of the pellet 22 electrically connected via a bonding wire 23. A plurality of inner leads 18 connected to each other, and outer leads 1 connected to the respective inner leads 18.
9 and a resin sealing body 25 in which the pellets 22, the tab 16, a part of the heat sink 15, and each inner lead 18 are resin-sealed. Outer lead 19 group and both heat sinks 1
The protruding portions 5 and 15 protrude outside from a pair of side surfaces on the long side of the resin sealing body 25 and are formed in a gull-wing shape.

The resin sealing body 25 is formed in a rectangular flat plate shape in a plan view, and a tab 16 is formed on a lower surface of a pair of main surfaces (hereinafter referred to as an upper surface and a lower surface) facing each other.
The lower surface of the resin sealing body 25 is exposed, and both pressing portion marks 40, which are the marks of the pressing portion used to expose the tab 16, are provided at the center of both short sides on the upper surface of the resin sealing body 25.
A and 40A are respectively formed.

Hereinafter, an embodiment of the present invention will be described.
A method for manufacturing an IC will be described. By this explanation, SOP
The details of the above-described configuration for the IC will be disclosed together.

In the method of manufacturing the SOP IC, the multiple lead frame 11 shown in FIG. 2 is used. The multiple lead frame 11 is manufactured and prepared by a multiple lead frame forming process. Multiple lead frame 11
A thin plate made of a spring material having relatively high mechanical strength such as an iron-nickel alloy or phosphor bronze is used, and is integrally formed by punching press processing or etching processing. Silver (Ag) on the surface of the multiple lead frame 11
A plating film (not shown) is partially or entirely applied so that wire bonding described later is appropriately performed. In the multiple lead frame 11, a plurality of unit lead frames 12 are arranged in a row in the horizontal direction. However, for convenience, only one unit is shown.

The unit lead frame 12 has a positioning hole 13
a is provided with a pair of outer frames 13 in which the two outer frames 13 are provided. The two outer frames 13, 13 are arranged in parallel at a predetermined interval and extend in series. A pair of section frames 14 are disposed between the adjacent unit lead frames 12 and 12 in parallel with each other between the outer frames 13 and 13 to be integrally bridged, and a rectangle formed by these outer frames and the section frames is formed. A unit lead frame 12 is formed in a frame (frame).

A pair of dam members 1 are provided between the outer frames 13 and 13.
7 and 17 are arranged in parallel inside the section frames 14 and 14, respectively, and are erected. Both dam members 1
A pair of heat radiating plates 15, 15 as tab connecting members connected to the tabs are protruded in an isosceles triangular shape at the ends of the outer rims 13, 17 at the ends of the heat radiating plates 15, 15. A rectangular tab 16 is integrally supported therebetween. Both the heat radiating plates 15 and 15 are bent near the tabs 16, respectively. The bending of each of the heat radiating plates 15 causes the tab 16 to move more than the surface of an inner lead group described later.
It is lowered by the thickness of a pellet described later (so-called tab lowering).

A plurality of inner leads 18 are arranged on the inner side of the dam member 17 at equal intervals in the longitudinal direction.
Each of the inner leads 18 is disposed so as to surround the tab 16 at the inner end thereof. On the other hand, the same number of outer leads 19 as the inner leads 18 are arranged on the outer end side of the dam member 17 so as to face the inner leads 18.
8 and are integrally protruded. The outer end of each outer lead 19 is connected to the section frame 14, respectively. The portion between the adjacent outer leads 19 in the dam member 17 substantially constitutes a dam 17a for damping the flow of the resin at the time of molding the resin sealing body described later.

In the unit lead frame 12, on both outer frames 13 and 13, resin-sealed-body suspending leads 20 for suspending the resin-sealed body are respectively disposed at the centers and protrude at right angles. Each of the resin sealing body suspension leads 20 is formed in a U-shape, and both ends of the U-shape are short-circuited to the outer frame 13.

The multiple lead frame 11 according to the above configuration prepared in the multiple lead frame forming step includes:
In the pellet bonding step and the wire bonding step, a pellet bonding operation is performed, followed by a wire bonding operation. These bonding operations are sequentially performed for each unit lead frame by feeding the multiple lead frames at a pitch in the horizontal direction.

First, a pellet 22 as a semiconductor integrated circuit structure in which an integrated circuit is formed in a so-called pre-process in a manufacturing process of a semiconductor device by a pellet bonding operation, as shown in FIG. It is arranged at a substantially central portion on the tab 16 of the unit lead frame 12, and is bonded by being mechanically fixed by a bonding layer 21 formed between the tab 16 and the pellet 22. As a means for forming the bonding layer 21, a bonding method using a gold-silicon eutectic layer, a soldering layer, a silver paste adhesive layer, or the like can be used.

Subsequently, as shown in FIG. 3, each bonding pad 22 of the pellet 22 bonded on the tab 16 is formed by a wire bonding operation.
A bonding wire 23 is bonded between the inner lead 18 and each inner lead 18 by using a wire bonding device (not shown) such as an ultrasonic thermocompression bonding wire bonding device. Get entangled. As a result, the integrated circuit formed in the pellet 22 is electrically drawn out to the outside via the bonding pad 22a, the bonding wire 23, the inner lead 18 and the outer lead 19.

As described above, the pellet and the wire
In the bonded assembly 24 shown in FIG. 3, a group of resin sealing bodies 25 for performing resin sealing for each unit lead frame is provided with the transfer molding apparatus 3 shown in FIG.
0 is used to simultaneously mold the group of unit lead frames 12.

The transfer molding apparatus 30 shown in FIG. 4 includes a pair of upper mold 31 and lower mold 32 which are clamped to each other by a cylinder device or the like (not shown).
On the mating surface of the upper mold 31 and the lower mold 32, a plurality of sets of upper mold cavity recesses 33a and lower mold cavity recesses 33b are respectively provided so as to form the cavities 33 in cooperation with each other.

The upper mold cavity recessed portion 33a and the lower mold cavity recessed portion 33b are each formed in a substantially rectangular hole shape when viewed from a plane. Upper cavity recess 33
In the center of both short sides of the ceiling surface of a, the heat radiating plate 15 as a tab connecting member is pushed in the direction of the bottom surface of the lower mold cavity recessed portion 33b in the clamped state, so that the lower surface of the tab 16 is lowered. A pair of holding parts 40, 40 for pressing against the bottom surface of the base 33b are provided in a protruding manner. As shown in FIG. 4C, the holding portion 40 is formed in a semi-elliptical short column shape as shown in FIG.
Is formed as an inclined surface that descends toward the direction of the tab 16 (inward direction).

A pot 34 is set up on the mating surface of the upper die 31, and a cylinder device (not shown) is provided in the pot 34.
The plunger 35 which is moved forward and backward is inserted so that resin (hereinafter, referred to as resin) as a molding material can be fed. Cull 36 is pot 3 on the mating surface of lower mold 32
4 and a plurality of runners 37 are arranged radially so as to be connected to the cull 36, respectively. The other end of each runner 37 is connected to the lower cavity recess 33b, and a gate 38 is formed at the connection so that the resin can be injected into the cavity 33. Also, a rectangular shape slightly larger than the outer shape of the multiple lead frame 11 and a constant depth substantially equal to the thickness of the multiple lead frame 11 are provided on the mating surface of the lower mold 32 so that the escape recess 39 can escape the thickness of the lead frame. Has been submerged.

At the time of transfer molding, the assembly 24 according to the above structure is accommodated in a relief recess 39 in which the multiple lead frames 11 are submerged in the lower die 32, and the pellets 22 in each unit lead frame 12 are They are arranged and set to be accommodated in the tees 33, respectively. In this state, the lower surface of the tab 16 slightly floats from the bottom surface of the lower cavity recess 23b.

Subsequently, the upper mold 31 and the lower mold 32 are clamped. In this state, the upper mold cavity concave portion 33a
Are pressed from above by contacting the heat radiating plates 15, 15 of the assembly 24 with the central portions of the bases of the isosceles triangles of the heat radiating plates 15, 15 from above, respectively. . At this time, since each of the heat radiating plates 15 is connected to the dam members 17 and 17 at both base angles of the isosceles triangle, the stress generated in the heat radiating plate 15 by being pressed by the pressing portion 40 is reduced. Will be absorbed by the part. In addition, since the lower surface of the holding portion 40 is formed on an inclined surface that becomes lower toward the inside, both the heat radiating plates 15, 15 are attached to the holding portions 40, 40.
As a result, the lower surface of the tab 16 is evenly pressed against the bottom surface of the lower mold cavity recess 33b. As a result, the lower surface of the tab 16 is strongly pressed against the bottom surface of the lower cavity recess 33b and comes into close contact therewith. Pressed strongly, lower cavity recess 33b
The tab 16 which is in close contact with the bottom surface is restricted in position within the cavity 33.

Thereafter, the resin 41 is fed from the pot 34 to the respective cavities 33 through the runner 37 and the gate 38 by the plunger 35 and injected. The pellet 2 is formed by the resin 41 injected into the cavity 33.
2 is in a state in which a lateral force is applied, but the tab 16
Is pressed against the bottom surface of the lower cavity recess 33b by the holding portions 40, 40, so that the tab 16, that is, the pellet 22 does not move. Therefore,
The displacement of the tab 16 caused by the movement of the tab 16, the exposure of the wire 23 from the resin sealing body 25 and the movement of the wire 23
Short-circuit failure with the pellet 22 can be avoided beforehand.

The resin 41 injected into the cavity 33 tries to go under the lower surface of the tub 16,
Since the tab 16 is strongly pressed against the lower surface of the lower cavity concave portion 33b by the pressing portions 40 and 40 and is firmly adhered thereto, the resin 41 is reliably prevented from going under the tab 16. Therefore, it is possible to prevent the occurrence of defective sealing and poor appearance of the resin sealing body 25 due to the wraparound of the resin 41, and to avoid problems such as a decrease in yield.

After the resin is injected, the resin is thermally cured to form the resin sealing body 25. The upper mold 31 and the lower mold 32 are opened, and the resin sealing body is ejected by an ejector pin (not shown). 25 groups are released.

As described above, the resin sealed body 25 group is formed on the assembly 24, and the molded body 26 shown in FIG. 5 is manufactured. The tab 16, the pellet 2, and the like
2. The inner leads 18 and the wires 23 are in a resin-sealed state, and the lower surface of the tab 16 is
Is exposed on the lower surface of the. As described above, since the resin is reliably prevented from wrapping under the tab 16, the tab 16 is formed on the lower surface of the resin sealing body 25.
Are uniformly exposed on the lower surface of the tub 16, and no thin resin flash (so-called resin flash) is generated around the tab 16.

At the center of both short sides on the upper surface of the resin sealing body 25, each pressing portion mark 40A as a mark of each pressing portion 40 is formed in a semicircular hole shape. Since the pressing portion 40 has pressed the tab 16 in contact with the outer side edge of the heat radiating plate 15, the heat radiating plate 15 is exposed at the bottom surface of the pressing portion mark 40A. However, since the pressing portion traces 40A are located farthest from the tabs 16, that is, the pellets 22 by being located on the outermost side of the resin sealing body 25 from the tabs 16, the moisture resistance of the tabs 16 and the pellets 22 is not reduced. .

Thereafter, a lead cutting and forming step (not shown)
In the above, the outer frame 13, the section frame 14, and the dam 17a are cut off for each unit lead frame, and each outer lead 19 is bent into a gull-wing shape. At this time, a part of the heat radiating plate 15 is projected outside the resin sealing body 25 as a heat radiating lead 27,
Is bent into a gull-wing shape so as to correspond to the outer lead 19. As described above, the SOP IC 28 having the configuration shown in FIG. 1 is manufactured.

According to the above-described embodiment, the following effects can be obtained.

At the time of molding the resin sealing body, the radiator plate connected to the tab is pressed by the pressing portion projecting from the cavity to press the tab against the bottom surface of the cavity, so that the lower surface of the tab is formed of the resin sealing body. Since the lower surface can be exposed, the heat dissipation performance of the SOP IC can be improved.

By pressing the heat radiating plate by the pressing portion to strongly press the tab against the bottom surface of the lower cavity concave portion so as to firmly adhere thereto, it is possible to prevent the resin from going under the tab, so that the resin goes around. Therefore, it is possible to prevent the occurrence of poor sealing and poor appearance of the resin-sealed body due to the above, and to avoid problems such as a decrease in yield.

A pressing portion for pressing the tab against the bottom surface of the lower cavity of the lower mold cavity is disposed at the center of both short sides on the upper surface of the resin sealing body, so that the pressing portion traces from the tab of the resin sealing body. Since it can be located on the outermost side, it is possible to prevent the moisture resistance of the tab or the pellet from being degraded by the pressing part trace.

At the time of molding the resin-sealed body of the SOP IC, the tab is pressed against the bottom surface of the concave portion of the lower mold cavity, so that it is possible to prevent the resin injected into the cavity from floating the tab. In addition, the displacement of the tab caused by the movement of the tab, the exposure of the wire from the resin sealing body, the short-circuit failure of the wire with the pellet, and the like can be avoided.

As described above, the SOP / IC can be further thinned, and the quality of the SOP / IC can be further improved.

Since the pressing portion for pressing the tab against the bottom surface of the concave portion of the lower mold cavity can be formed by projecting into the cavity of the molding die for molding the resin sealing body, the transfer molding device needs to be modified. It can be minimized.

FIG. 6 shows a second embodiment of the present invention.
IC is shown.

The second embodiment is different from the first embodiment in that an IC having a quad flat package is provided.
(Hereinafter, referred to as QFP · IC) 29, and the resin sealing body 25 </ b> A in this QFP · IC 29.
Each of the four corners has a mark 40A for holding down the tab suspension lead 15A as a tab connecting member, and the tab 16 is exposed on the back surface of the resin sealing body 25A.

According to this embodiment, since the tab 16 is exposed on the back surface of the resin sealing body 25A, the same operation and effect as those of the above embodiment can be obtained.

Although the invention made by the present inventor has been specifically described based on the embodiment, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention. Needless to say.

For example, the portion of the heat radiating plate protruding outside the resin sealing body is not limited to a heat radiating lead, but may be a heat radiating fin. Further, the heat sink may be omitted.

A radiation fin may be provided on one main surface of the tab exposed on one main surface of the resin sealing body.

In the above description, the invention made mainly by the present inventor is based on the SOP which is
-Although mainly applied to ICs and QFP ICs, the present invention is not limited to this, and resin-sealed packages such as other surface-mounted resin-sealed package ICs and insertion-type resin-sealed package ICs The present invention can be applied to all semiconductor devices including In particular, the present invention can be applied to a semiconductor device having a thin resin-sealed package to obtain excellent effects.

[0048]

The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.

At the time of molding the resin sealing body, the tab connecting member connected to the tab is pressed by the pressing portion protruding from the cavity to press the tab against the bottom surface of the cavity, thereby lowering the lower surface of the tab. Can be exposed on the lower surface of the semiconductor device, so that the heat dissipation performance of the semiconductor device can be improved.

By pressing the tab connecting member with the pressing portion and pressing the tab against the bottom surface of the cavity, the pressing portion mark can be separated far from the tab, so that the moisture resistance of the semiconductor pellet is deteriorated and the appearance of the resin sealing body is reduced. Performance degradation can be prevented.

[Brief description of the drawings]

1A and 1B show an SOP IC according to an embodiment of the present invention, in which FIG. 1A is a bottom view in which a left half is partially omitted and a plan view in which a right half is partially omitted, and FIG. Figure,
(C) is a partially cut side view.

FIG. 2 is a partially omitted plan view showing a multiple lead frame used in the SOP / IC manufacturing method.

3A and 3B show a pellet and a state after a wire bonding step, wherein FIG. 3A is a partially omitted plan view, and FIG. 3B is a front sectional view.

4A and 4B show a molding process of a resin sealing body, in which FIG. 4A is a partially omitted front sectional view, FIG. 4B is a sectional view taken along line bb of FIG. 4A, and FIG. FIG. 2 is a cross-sectional view taken along line c-c.

FIG. 5 shows the assembly after molding the resin sealing body;
(A) is a bottom view in which a left half is partially omitted and a plan view in which a right half is partially omitted, and (b) is a partially cut front view.

FIGS. 6A and 6B show a QFP IC according to a second embodiment of the present invention, wherein FIG. 6A is a plan view of an upper half and a bottom view of a lower half, FIG. Is a partially omitted side sectional view along a diagonal line.

[Explanation of symbols]

11: Multiple lead frame, 12: Unit lead frame, 13: Outer frame, 14: Section frame, 15: Heat sink (tab connecting member), 15A: Tab suspension lead, 16: Tab, 17: Dam member, 17a ... Dam, 18: inner lead, 19: outer lead, 20: resin-encapsulated body suspending lead, 21: bonding layer, 22: pellet, 22a ...
Bonding pad, 23 wire, 24 assembly, 2
5, 25A: resin molded body, 26: molded body after molded resin molded body, 27: heat radiation lead, 28: SOP / IC (semiconductor device), 29: QFP / IC (semiconductor device), 30: transfer molding Apparatus, 31 ... upper mold, 32 ... lower mold, 33 ...
Cavity, 33a ... upper mold cavity recess, 33b
... Lower cavity recesses, 34 pots, 35 plungers, 36 culls, 37 runners, 38 gates, 39
... escape recess, 40 ... holding part, 40A ... holding part mark, 4
1. Resin.

Claims (10)

[Claims] 1. A semiconductor pellet, a tab to which the semiconductor pellet is bonded, a plurality of inner leads connected to each outer lead and electrically connected to the semiconductor pellet, a semiconductor pellet, a tab and each inner lead. A semiconductor device comprising: a resin-sealed resin-sealed body; wherein a tab connecting member connected to the tab is pushed in a thickness direction of the resin-sealed body during molding of the resin-sealed body; A main surface of the semiconductor device is exposed on one main surface of the resin sealing body. 2. The semiconductor device according to claim 1, wherein the tab connecting member is formed as a heat sink. 3. The semiconductor device according to claim 2, wherein a part of said heat radiating plate is formed thin so as to relieve stress. 4. A part of the heat radiating plate is projected outside the resin sealing body, and the projected portion is formed as a heat radiating lead formed and arranged so as to correspond to the outer lead. 4. The semiconductor device according to claim 2, wherein: 5. The semiconductor according to claim 2, wherein a part of the heat radiating plate protrudes outside the resin sealing body, and the protruding part is configured as a heat radiating fin. apparatus. 6. The semiconductor device according to claim 1, wherein the tab connecting member is formed as a tab suspension lead. 7. The method of manufacturing a semiconductor device according to claim 1, wherein the resin sealing body is formed by filling a molding resin into a cavity of a molding die. In the method of manufacturing a semiconductor device provided, a tab connecting member connected to the tab is pressed on an inner surface of the cavity in a thickness direction of the resin sealing body at the time of molding the resin sealing body. A method for manufacturing a semiconductor device, comprising: a holding portion for pressing a semiconductor device. 8. The method of manufacturing a semiconductor device according to claim 7, wherein a lower surface of said holding portion is formed as an inclined surface which decreases as going toward a tab. 9. The method of manufacturing a semiconductor device according to claim 7, wherein said pressing portion presses a tab connecting member formed as a heat sink. 10. The method of manufacturing a semiconductor device according to claim 7, wherein the pressing portion is configured to press a tab connecting member formed as a tab suspension lead.