JP2002057265A - Semiconductor device and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase yield and connection reliability at mounting by preventing the crawling of leads, in a resin-encapsulated semiconductor device. SOLUTION: The semiconductor device comprises a sealed section 3 where a semiconductor chip 2 is resin-encapsulated, a tab 1b for supporting the semiconductor chip 2, a plurality of leads 1a which are disposed in parallel with each other in the periphery of a rear face 3a of the sealed section 3 with mounting faces 1d being exposed, and wires 4 for connecting pads 2a of the semiconductor chip 2 and corresponding leads 1a. When assembling the semiconductor device, each lead 1a is molded, by making the mounting face 1d of the lead 1a adhere closely to a cavity formation face 6d of a lower metal mold 6b and then clamping it to the mold, using a lead frame 1 which is bent, in advance towards the mounting face 1d side of the lead 1a. Thereby, the mounting face 1d of each lead 1a can be exposed surely on the rear face 3a of the sealed section 3, so that crawling of the leads into the encapsulated section 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing technique, and more particularly to a technique which is effective when applied to a semiconductor device of a peripheral type to prevent lead penetration.

[0002]

2. Description of the Related Art The technology described below studies the present invention,
Upon completion, they were examined by the inventor, and the outline is as follows.

As a miniaturized semiconductor device, QFN
A small semiconductor package called a “Quad Flat Non-leaded Package” slightly larger than a semiconductor chip has been developed, and this QFN is assembled using a thin plate-like lead frame.

In the QFN, a plurality of leads serving as external terminals are arranged on a peripheral portion of a back surface (a surface on a semiconductor device mounting side) of a sealing portion formed by molding so that a mounting surface thereof is exposed. A semiconductor package having such a structure is called a peripheral type.

[0005] The structure of QFN assembled using a lead frame is described in, for example, “Journal of Semico,” published by Press Journal on July 27, 1998.
Nector World Special Issue '99 Semiconductor Assembly and Inspection Technology ", pp. 53-57.

[0006]

However, in the QFN of the above-mentioned technique, if the lead is deformed upward at the stage of molding during the assembly, the lead is clamped by a mold when the lead frame is clamped. In this state, the surface of the sealing portion is slightly floated from the cavity forming surface without being in close contact with the cavity forming surface.

[0007] This phenomenon may occur due to the clamping state of the mold even if the lead is not deformed. If the molding is performed in such a state, the lead will be formed in the cavity of the mold. The sealing resin forms around the lower side (back side) of the sealing portion, and therefore, when the sealing portion is completed, the lead sneaks into the sealing portion, whereby the lead on the back surface of the sealing portion is formed. Becomes insufficiently exposed.

As a result, there is a problem that a defective product due to plating failure occurs without plating being applied to the mounting surface of the lead and the yield of QFN is reduced, and that connection reliability during mounting is reduced. .

[0009] As a measure for preventing lead sneaking in the QFN, a method of performing molding using a film sheet has been devised. However, molding using a film sheet is expensive and costly for remodeling a molding apparatus. It takes a lot of time and trouble.

An object of the present invention is to provide a semiconductor device and a method of manufacturing the same, which prevent lead dive and improve yield and connection reliability during mounting.

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.

[0012]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, in the semiconductor device of the present invention, a tab for supporting the semiconductor chip, a sealing portion formed by sealing the semiconductor chip with a resin, and an exposed surface of the sealing portion on the semiconductor device mounting side. A plurality of leads including a mounting surface to be mounted and a protruding portion slightly protruding from a side surface of the sealing portion, wherein the protruding portion faces a surface of the sealing portion opposite to a surface on the semiconductor device mounting side. And a connection member for connecting the surface electrode of the semiconductor chip and the corresponding lead.

Further, a method of manufacturing a semiconductor device according to the present invention
A tab that supports the semiconductor chip, and a plurality of leads that have a mounting surface that is exposed to the semiconductor device mounting side surface of the sealing portion when sealed with resin and are bent toward the mounting surface. A step of preparing a lead frame; a step of joining the tab of the lead frame to the semiconductor chip; and a step of connecting a surface electrode of the semiconductor chip and the corresponding lead of the lead frame by a connection member. Clamping the mold by bringing the mounting surface of the lead into close contact with a cavity forming surface corresponding to the surface of the mold on the semiconductor device mounting side by bending the lead; and The sealing resin is supplied to the cavity so that the mounting surface of the lead is exposed to the semiconductor device mounting side surface of the sealing portion. Those having a step of resin-sealing said semiconductor chip to form a sealing portion, and a step of cutting and separating the lead from the lead frame.

According to the present invention, when the lead frame is clamped by the mold during the molding, the lead is pressed against the cavity forming surface corresponding to the semiconductor device mounting side of the mold by bending the lead. When the mold is clamped, the mounting surface of the lead can be brought into close contact with the cavity forming surface of the mold.

Accordingly, the sealing resin does not flow to the back side (lower side) of the lead during molding, so that when the sealing portion is formed, the mounting surface of the lead is securely attached to the back surface of the sealing portion. Can be exposed.

Accordingly, it is possible to prevent the lead from getting into the sealing portion. As a result, the plating can be sufficiently applied to the mounting surface of the lead, so that it is possible to prevent the occurrence of plating failure due to the lead sunk, thereby improving the yield of the semiconductor device.

Further, the method of manufacturing a semiconductor device according to the present invention has a tab for supporting a semiconductor chip and a plurality of leads having a mounting surface that can be exposed on a surface of the sealing portion on the semiconductor device mounting side. A step of preparing a lead frame; a step of joining the tab of the lead frame to the semiconductor chip; and a step of connecting a surface electrode of the semiconductor chip and the corresponding lead of the lead frame by a connection member. And a clamp surface of the first and second molds, wherein a clamp surface for clamping the lead is bent outward from the cavity forming surface toward the concave side of the cavity in the mold including the first and second molds. The lead frame is clamped by a surface, and the mounting surface of the lead corresponds to the surface of the molding die on the semiconductor device mounting side. Contacting the cavity forming surface, and supplying a sealing resin to the cavity of the mold so that the mounting surface of the lead is exposed on the semiconductor device mounting side surface of the sealing portion. A step of forming the sealing portion and sealing the semiconductor chip with a resin; and a step of cutting and separating the lead from the lead frame.

Further, a method of manufacturing a semiconductor device according to the present invention
A step of preparing a lead frame having a tab supporting the semiconductor chip and a plurality of leads having a mounting surface that can be exposed on the surface of the sealing portion on the semiconductor device mounting side, and the tab of the lead frame; Bonding the semiconductor chip to the semiconductor chip, connecting the surface electrode of the semiconductor chip and the corresponding lead of the lead frame by a connecting member, and mounting the lead on a clamp surface of a mold. The lead frame is clamped by the clamp surface of the mold provided with a protrusion for pressing the surface opposite to the surface, and the surface of the lead opposite to the mounting surface of the lead is pressed by the protrusion. Bringing the mounting surface of the lead into close contact with a cavity forming surface corresponding to the surface of the molding die on the semiconductor device mounting side, and A sealing resin is supplied to the cavity to form the sealing portion so that the mounting surface of the lead is exposed on the semiconductor device mounting side surface of the sealing portion, and the semiconductor chip is sealed with a resin. Stopping the lead and cutting the lead at a concave portion of the lead formed by the convex portion of the mold to separate the lead from the lead frame.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, members having the same functions are denoted by the same reference numerals, and the repeated description thereof will be omitted.

(Embodiment 1) FIGS. 1A and 1B are views showing an example of the structure of a semiconductor device (QFN) according to Embodiment 1 of the present invention, wherein FIG. 1A is a plan view, FIG. c) is a bottom view, FIG. 2 is an enlarged cross-sectional view showing the structure of the semiconductor device shown in FIG. 1, and FIG. 3 is a cross-sectional view showing an example of an assembled state corresponding to main steps in the method of manufacturing the semiconductor device shown in FIG. FIG. 4A is a sectional view showing an example of an assembled state corresponding to a main step in the method of manufacturing the semiconductor device shown in FIG. () Shows a state before the mold clamping in the molding step, (b) shows a resin injection state after the mold clamping in the molding step, and (c) shows a cutting step.

The semiconductor device according to the first embodiment shown in FIG. 1 is a small semiconductor package of a resin-sealed type and a surface-mounted type, and a back surface of a sealing portion 3 formed by molding (semiconductor device mounting). This is a peripheral type in which a mounting surface 1d of a plurality of leads 1a, which are external terminals, is exposed and arranged on a peripheral portion of a side surface 3a. A QFN 5 will be described as an example of the semiconductor device.

Therefore, each lead 1a of QFN5 is
The inner lead buried in the sealing portion 3 and the outer lead exposed at the peripheral portion of the back surface 3a of the sealing portion 3 have both functions.

The QFN 5 here has a tab embedded structure in which a tab 1 b for supporting the semiconductor chip 2 is embedded in the sealing portion 3.

The detailed configuration of the QFN 5 will be described with reference to FIGS. 1 and 2. The QFN 5 includes a sealing portion 3 formed by resin-sealing the semiconductor chip 2 and a chip supporting surface 1c for supporting the semiconductor chip 2. Tab 1b, a tab suspending lead 1e that supports the tab 1b and is exposed at four corners of a peripheral edge of the back surface 3a of the sealing portion 3, and is disposed around the tab 1b and sealed. A plurality of leads 1a arranged so as to expose the surface to be mounted 1d side by side with the peripheral portion of the back surface 3a of the portion 3
And a bonding wire (connecting member) 4 for connecting a pad (surface electrode) 2a of the semiconductor chip 2 and a corresponding lead 1a. When assembling the QFN 5, as shown in FIG. As shown in FIG. 4 (b), in the molding process, each lead 1a uses a lead frame 1 which is bent in advance to the mounting surface 1d side.
The mounting surface 1d of the lead 1a is brought into close contact with the cavity forming surface 6d of the lower die (first die) 6b of the molding die 6, and the upper die (second die) 6a and the lower die 6b are clamped. It was assembled by performing molding.

As a result, as shown in FIG. 1 (c), each lead 1a is provided on the peripheral portion of the back surface 3a of the sealing portion 3.
The mounting surface 1d is surely exposed to prevent the lead from slipping into the sealing portion 3.

Note that, as shown in FIG.
Is fixed on the chip supporting surface 1c of the tab 1b by a die bonding material (for example, silver paste) 12.

The tab 1b, the tab suspension lead 1e and each lead 1a are formed of a thin plate material such as copper, for example, and have a thickness of about 0.15 to 0.2 mm.

Further, the wire 4 connecting the pad 2a of the semiconductor chip 2 and the corresponding lead 1a is, for example, a gold wire.

Further, the sealing portion 3 is formed by resin sealing by a molding method, and FIG.
Is a thermosetting epoxy resin, for example.

Next, a method of manufacturing the QFN 5 according to the first embodiment will be described.

First, a tab 1b having a chip supporting surface 1c capable of supporting the semiconductor chip 2 and a mounting surface 1d which is exposed at a peripheral portion of the back surface 3a of the sealing portion 3 when sealed with resin are provided. A lead frame 1 shown in FIG. 3A having a plurality of leads 1a bent toward the mounting surface 1d.
Prepare

The lead 1 of the lead frame 1
The bending position of “a” is the same as that of the mounting surface 1 except for the mounting surface 1 d.
3 (a), the bending angle (θ) at that time is the bonding surface 1f, which is the surface on the opposite side of the mounting surface 1d. On the mounting surface 1d side, for example, 0.
It is about 1 to 30 °, but may exceed 30 °.

Here, the lead frame 1 is a strip-shaped elongated multiple unit capable of manufacturing a plurality of QFNs 5 from one lead frame 1.
A plurality of package regions corresponding to one QFN 5 are formed on one lead frame 1.

The lead frame 1 is a thin plate made of, for example, copper (Cu) and has a thickness of, for example, about 0.15 to 0.2 mm. However, the present invention is not limited to these.

Subsequently, a semiconductor chip 2 having a semiconductor integrated circuit formed on the main surface 2b is prepared. Thereafter, the chip supporting surface 1c of the tab 1b of the lead frame 1 and the back surface 2c of the semiconductor chip 2 (opposite to the main surface 2b). Die bonding (also referred to as pellet bonding or chip mounting).

At this time, the semiconductor chip 2 is fixed to the tab 1b of the lead frame 1 via the die bonding material (for example, silver paste) 12 with the main surface 2b facing upward.

Subsequently, as shown in FIG. 3B, the pads 2a of the semiconductor chip 2 and the corresponding leads 1a are connected by wire bonding using bonding wires 4 as connection members.

Thereafter, the semiconductor chip 2 is sealed with a resin by a mold (here, transfer mold).

Here, after the lead frame 1 after wire bonding is clamped by the upper mold 6a and the lower mold 6b of the mold 6 shown in FIG.
A resin molding is performed by supplying a liquid sealing resin 7 therein.

In the molding step, first, as shown in FIG. 4A, the lead 1 is placed on the clamp surface 6e of the lower mold 6b.
a, the lead frame 1 in which the bending to the mounting surface 1d side is formed is arranged, and then, as shown in FIG.
The lead frame 1 is clamped by the upper mold 6a and the lower mold 6b.

At this time, since the lead 1a is bent toward the mounting surface 1d, the lead 1a is pressed by the upper mold 6a onto the lead frame 1 so that the lead 1a is
Therefore, when the upper mold 6a and the lower mold 6b are completely clamped, the mounting surface 1d of the lead 1a is moved to the cavity forming surface 6d of the lower mold 6b (the sealing portion 3).
(The mold surface corresponding to the back surface 3a).

Subsequently, in this mold clamp state, the sealing resin 7 is injected (supplied) into the cavity 6c so that the mounting surface 1d of the lead 1a is securely exposed on the back surface 3a of the sealing portion 3. A stop 3 is formed. In the first embodiment, the mounting surface 1d of the lead 1a is the cavity forming surface 6 of the lower mold 6b.
d, the sealing resin 7 is provided between the mounting surface 1d of the lead 1a and the cavity forming surface 6d of the lower mold 6b.
Therefore, after the sealing portion is formed, the mounting surface 1d of the lead 1a can be reliably exposed on the back surface 3a.

Thereafter, each of the leads 1a and the tab hanging leads 1e is cut and separated from the lead frame 1 (individualization), whereby the QF shown in FIGS.
N5 is completed.

QFN 5 of First Embodiment (Semiconductor Device)
According to the method and the method for manufacturing the same, the following effects can be obtained.

That is, in the manufacture of the QFN 5, molding is performed by using the lead frame 1 having a plurality of leads 1a bent toward the mounting surface 1d side.
When the lead frame 1 is clamped by the upper die 6a and the lower die 6b of the molding die 6, the lead 1a is bent by the bending of the lead 1a so that the lower die 6b of the molding die 6 is bent.
Is pressed against the cavity forming surface 6d of the lower die 6b.
d.

Thus, the cavity 6c at the time of molding is formed.
When the sealing resin 7 is injected into the
Since the encapsulating portion 3 is not formed, the mounting surface 1d of the lead 1a can be reliably exposed on the back surface 3a of the encapsulating portion 3 because the encapsulating portion 3 is not formed.

Therefore, it is possible to prevent the lead from getting into the sealing portion 3 and, as a result, it is possible to prevent the formation of resin flash burrs on the mounting surface 1d of the lead 1a.

As a result, since the solder plating can be sufficiently applied to the mounting surface 1d of the lead 1a, it is possible to prevent the occurrence of plating failure due to the lead 1a sunk, and as a result, the QFN5 (semiconductor device) Yield can be improved.

Further, since the solder plating can be sufficiently applied to the mounting surface 1d of the lead 1a, the Q
The connection reliability at the time of mounting the FN5 on a mounting board or the like can be improved.

Further, since it is not necessary to perform molding using a film sheet, it is possible to suppress an increase in the cost of the QFN 5 and to prevent the lead 1a from sneaking in.

(Embodiment 2) FIGS. 5A and 5B show an example of a structure and a mounting state of a semiconductor device (QFN) according to Embodiment 2 of the present invention. FIG. 5A is a sectional view of the QFN, and FIG. FIG. 6 is a cross-sectional view showing an example of an assembled state corresponding to main steps in the method of manufacturing the semiconductor device shown in FIG. 5, (a) is a molding step, (b) is a plating step, c) is a cutting step.

In the semiconductor device of the second embodiment, similarly to the semiconductor device of the first embodiment, the mounting surface 1d of the plurality of leads 1a is exposed at the peripheral portion of the back surface 3a of the sealing portion 3 in a line. It is a QFN5 of the arranged peripheral type.

The structure of the QFN 5 according to the second embodiment is the same as that of the tab 1 having the chip supporting surface 1 c for supporting the semiconductor chip 2.
b, a sealing portion 3 formed by resin-sealing the semiconductor chip 2, and a mounting surface 1 d which is arranged around the tab 1 b and is exposed at a peripheral portion of the back surface 3 a of the sealing portion 3. A plurality of leads 1a having a protrusion 1g slightly protruding from a side surface 3b of the portion 3 and having the protrusion 1g facing a surface 3c opposite to the back surface 3a of the sealing portion 3; And a bonding wire 4 for connecting the corresponding pad 2a to the corresponding lead 1a.

That is, QFN5 of the second embodiment is
As shown in FIG. 5A, the protrusion of the lead 1 a is such that the tip of the protrusion 1 g of the lead 1 a slightly protruding from the side surface 3 b of the sealing portion 3 faces the surface 3 c of the sealing portion 3. 1 g is formed by bending on the surface 3 c side of the sealing portion 3.

That is, assuming that the front surface 3c side of the sealing portion 3 is the upper side and the back surface 3a side is the lower side, each lead 1a is formed by bending so that the tip of the protruding portion 1g is directed upward.

The remaining structure of the QFN 5 according to the second embodiment is the same as that of the QFN 5 according to the first embodiment, and a description thereof will not be repeated.

Next, a method of manufacturing the QFN 5 according to the second embodiment will be described.

The main assembling procedure of the QFN 5 of the second embodiment is almost the same as that of the QFN 5 of the first embodiment.
Therefore, the description of the second embodiment will focus on differences from the manufacturing method of the first embodiment.

First, the tab 1b on which the chip supporting surface 1c for supporting the semiconductor chip 2 is formed, and the back surface 3a of the sealing portion 3
A lead frame 1 having a plurality of leads 1a having a mounting surface 1d that can be exposed to the outside is prepared.

That is, the lead 1a of the lead frame 1 according to the second embodiment has the same structure as that of the first embodiment shown in FIG.
The lead frame 1 shown in (a) has a flat structure in which no bending is formed like the lead 1a.

Further, after preparing the semiconductor chip 2 having the semiconductor integrated circuit formed on the main surface 2b, the semiconductor chip 2 is supplied, and the chip supporting surface 1c of the tab 1b of the lead frame 1 and the back surface 2c of the semiconductor chip 2 are provided. Die bonding is performed to join them.

Then, the pads 2a of the semiconductor chip 2 and the corresponding leads 1a are connected to the bonding wires 4a.
Wire bonding.

Thereafter, the semiconductor chip 2 is formed by molding.
Is sealed with a resin.

In the second embodiment, as shown in FIG. 6A, the clamp surfaces 6e of both the upper die 6a and the lower die 6b for clamping the lead 1a are located close to the respective cavity forming surfaces 6d. Molding is performed using a mold 6 composed of an upper mold 6a (second mold) and a lower mold 6b (first mold) bent outward to the concave side of the cavity.

That is, the flat lead frame 1 is clamped by the two clamp surfaces 6e by utilizing the bending of the clamp surfaces 6e of the upper mold 6a and the lower mold 6b, so that the flat leads are formed when the mold is clamped. The mounting surface 1d of the lead 1a is lowered by the elastic force of the lower die 6b.
Is adhered to the cavity forming surface 6d.

In this state, molding is performed by injecting the sealing resin 7 (see FIG. 4B) into the cavity 6c, so that the mounting surface 1 of the lead 1a is formed as in the first embodiment.
d and the cavity 6c of the sealing resin 7 without entering the sealing resin 7 between the cavity forming surface 6d of the lower mold 6b.
Filling, and as a result, the back surface 3a of the sealing portion 3
Thus, the mounting surface 1d of each lead 1a can be reliably exposed.

The lead 1a is moved by the clamping force of the upper die 6a and the lower die 6b, as shown in FIG.
After molding, it is bent upward (plastically deformed) (toward the surface 3c of the sealing portion 3).

Thereafter, as shown in FIG. 6B, in a plating step, a solder plating layer 10 is formed on the lead surface.

Subsequently, as shown in FIG. 6 (c), in the cutting step, lead cutting (singulation) for cutting and separating each lead 1a from the lead frame 1 is performed.
The QFN 5 shown in FIG. 5A is completed.

At this time, as shown in FIG. 6C, in each lead 1a, the lead is cut at a position outside the bent portion (projection 1g).

As a result, as shown in FIG. 5A, in the QFN 5 according to the second embodiment, the leading end of the protruding portion 1g of each lead 1a projecting from the side surface 3b of the sealing portion 3 is upward (sealing). (The surface 3c side of the portion 3).

Here, FIG. 5B shows an embodiment of mounting the QFN 5 of the second embodiment on the mounting board 8.

That is, the QFN 5 is mounted on the mounting board 8 via the solder 9, and the mounting surface 1 of the lead 1 a is
d and a board-side terminal 8 a, which is a connection-side terminal of the mounting board 8, are connected via solder 9. At this time, since the QFN 5 of the second embodiment is formed by bending the tip of the protrusion 1g of each lead 1a upward, the solder fillet 11 can be formed sufficiently high, and as a result, the connection reliability can be improved. Performance (mountability) can be improved.

The other method of manufacturing the QFN 5 according to the second embodiment is the same as the method of manufacturing the QFN 5 according to the first embodiment, and a description thereof will not be repeated.

QFN5 of Second Embodiment (Semiconductor Device)
According to the method and the method for manufacturing the same, the following effects can be obtained.

That is, in the mold 6, the clamp surface 6 e for clamping the lead 1 a is formed by the lower mold 6 b and the clamp surface 6 e of the upper mold 6 a bent outward from the cavity forming surface 6 d toward the concave side of the cavity. By clamping the lead frame 1, the lead 1
The mounting surface 1d of a can be brought into close contact with the cavity forming surface 6d of the lower mold 6b of the mold 6.

Thus, at the time of molding, the sealing resin 7
Does not wrap around the back surface of the lead 1a, so that when the sealing portion 3 is formed, the lead 1a
1d can be exposed.

As a result, it is possible to prevent the lead from sneaking into the sealing portion 3, thereby preventing the formation of resin flash burrs on the mounting surface 1d of the lead 1a.

In the peripheral QFN 5, the protrusion 1 g of the lead 1 a slightly protruding from the side surface 3 b of the sealing portion 3 faces the surface 3 c side (upward) of the sealing portion 3. When mounted on the mounting board 8 or the like, a gap can be formed between the vicinity of the tip of the mounting surface 1d of the lead 1a and the board-side terminal 8a as a connection-side terminal.

As a result, when the QFN 5 is mounted on the mounting board 8 or the like, the solder 9 is buried in the gap, so that the solder fillet 11 can be formed sufficiently and high. Reliability can be improved.

Although the invention made by the inventor has been specifically described based on the first and second embodiments of the present invention, the present invention is not limited to the first and second embodiments of the invention. It goes without saying that various changes can be made without departing from the gist of the invention.

For example, as another manufacturing method for exposing the mounting surface 1d of the lead 1a on the back surface 3a of the sealing portion 3 in the QFN 5, the manufacturing method of the modification shown in FIGS. 7 and 8 may be used.

First, in a modification shown in FIG. 7, a convex portion 6f (for example, a convex portion 6 having a height of about 10 μm) pressing a bonding surface 1f of a lead 1a against a clamp surface 6e of an upper mold 6a.
Molding is performed using the mold 6 provided with f).

That is, as shown in FIG. 7A, the bonding surface 1f of the lead 1a is locally pressed by the convex portion 6f provided on the clamp surface 6e of the upper die 6a during the die clamping in the molding step. By doing, lead 1
squeeze and stretch the bonding surface 1f side of a,
As a result, the mounting surface 1d of the lead 1a is
Is brought into close contact with the cavity forming surface 6d of the lower mold 6b.

As a result, after molding, each lead 1a can be reliably exposed on the back surface 3a of the sealing portion 3, and the bonding surface 1f of the lead 1a is formed by the convex portion 6f of the upper die 6a as shown in FIG. The recess 1h shown in (b) is formed, and then the solder plating layer 10 is formed on the lead surface in the plating step, so that the solder plating layer 10 can be formed also in the recess 1h.

Further, in the cutting step, by cutting the lead 1a at the concave portion 1h, the solder plating layer 10 of the concave portion 1h goes around the entire side surface 1i of the lead 1a or to the upper side as shown in FIG. 7C. Therefore, after the lead is cut, the solder plating layer 1 is formed on the side surface 1i of the lead 1a to the upper side, that is, the bonding surface 1f side or its vicinity.
0 can be formed.

Therefore, as shown in FIG. 7 (d), the portion where the solder plating layer 10 is not adhered to the side surface 1i of the lead 1a is eliminated or reduced. As a result, when the QFN 5 is mounted on the mounting substrate 8 or the like, The solder plating layer 10 formed on the entire side surface 1i of the lead 1a or up to the upper side of the lead 1a rinses up the solder 9 arranged for connection with the substrate side terminal 8a, whereby the solder fillet 11 can be formed sufficiently and high. .

As a result, the connection reliability (mountability) at the time of mounting the QFN 5 can be improved.

8A, 8B, 8C, and 8D show a modification in which the lead 1a is provided on the clamp surface 6e of the upper mold 6a.
A convex portion 6f for pressing the bonding surface 1f of
In addition, molding is performed using a mold 6 having a small convex portion 6g smaller than the convex portion 6f for pressing the mounting surface 1d of the lead 1a on the clamp surface 6e of the lower die 6b.

That is, since the small convex portion 6g of the lower die 6b is smaller than the convex portion 6f of the upper die 6a, the bonding surface 1f of the lead 1a is connected to the mounting surface 1 during the die clamping.
By locally pressing with a pressure greater than d, the bonding surface 1f side of the lead 1a is crushed and extended, and as a result, as shown in FIG. It can be brought into close contact with the cavity forming surface 6d of the lower mold 6b.

Thus, after molding, each lead 1a can be reliably exposed on the back surface 3a of the sealing portion 3, and the bonding surface 1f of the lead 1a and the mounting surface 1
8D, a concave portion 1h shown in FIG. 8B is formed on each surface by the convex portion 6f of the upper mold 6a and the small convex portion 6g of the lower mold 6b.

Thereafter, in a plating step, a solder plating layer 10 is formed on the lead surface, so that the bonding surface 1 is formed.
The solder plating layer 10 can also be formed in the recess 1h on the mounting surface 1d and the mounting surface 1d. Further, in the cutting step, the lead 1a is cut by the recess 1h, so that the solder plating layer 10 in the recess 1h on both surfaces of the lead is formed. As shown in FIG. 8C, after the lead is cut, the lead 1
The solder plating layer 10 can be formed above the side surface 1i, that is, up to the bonding surface 1f side or its vicinity.

Therefore, similarly to the modification shown in FIG. 7, when the QFN 5 is mounted on the mounting board 8 or the like,
As shown in FIG. 3D, the solder plating layer 10 formed on the entire side surface 1i of the lead 1a or up to the upper side of the lead 1a cleans up the solder 9 arranged for connection with the board-side terminal 8a. Can be formed sufficiently and high.

Further, in the first and second embodiments and the modifications, the first and second molds of the mold 6 are described as the lower mold 6b and the upper mold 6a. The relationship between the upper mold 6a and the lower mold 6b in the mold 6 may be reversed.

Further, in the first and second embodiments and the modified examples, the case where the QFN 5 has the tab embedded structure has been described.
A tab exposure structure in which the tab 1b is exposed on the back surface 3a of the sealing portion 3 may be used.

Further, in the first and second embodiments and the modified examples, the case where the semiconductor device is the QFN5 has been described. However, if the semiconductor device is a resin-sealed type and a peripheral type semiconductor package, the QFN5 is used. Other than that may be used.

[0098]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1). By performing molding using a lead frame having a plurality of leads bent to the mounting surface side, when the lead frame is clamped by the mold, the leads are bent so that the leads are mounted on the semiconductor device mounting side of the mold. Therefore, the mounting surface of the lead can be brought into close contact with the cavity forming surface of the mold. Accordingly, the sealing resin does not flow around the back surface of the lead, and the mounting surface of the lead can be reliably exposed on the back surface of the sealing portion. Therefore, the plating can be sufficiently applied to the mounting surface of the lead, and as a result, it is possible to prevent the occurrence of plating failure due to the lead sneaking, and to improve the yield of the semiconductor device.

(2). Since the plating can be sufficiently applied to the mounting surface of the lead, the connection reliability at the time of mounting the semiconductor device can be improved. Further, since it is not necessary to perform the molding using the film sheet, it is possible to suppress an increase in the cost of the semiconductor device and to prevent the lead from sneaking in.

(3). At the time of molding, the lead frame is clamped by the clamp surface of the mold having a convex portion for pressing the surface opposite to the surface on which the lead is mounted on the clamp surface. Since the opposite surface is pressed and stretched, the lead is pressed against the cavity forming surface of the mold, so that the mounting surface of the lead can be brought into close contact with the cavity forming surface when clamping the mold. As a result, since the sealing resin does not flow around the back surface of the lead, when the sealing portion is formed, the mounting surface of the lead can be reliably exposed on the back surface of the sealing portion. Plating can be sufficiently applied to the surface. Therefore,
It is also possible to prevent the occurrence of plating failure due to lead sunk, and as a result, it is possible to improve the yield of semiconductor devices.

(4). At the time of cutting the lead, the lead is cut at the concave portion of the lead formed by the convex portion of the mold, so that the solder plating layer is formed on the side surface of the lead to near the surface opposite to the mounting surface. be able to. Thereby, the solder fillet can be formed high when the semiconductor device is mounted, and therefore, the connection reliability when the semiconductor device is mounted can be improved.

(5). At the time of molding, the mounting surface of the lead is molded by clamping the lead frame with the clamping surfaces of the first and second molds in which the clamping surface is bent outward from the cavity forming surface toward the concave side of the cavity. It can be in close contact with the cavity forming surface of the mold. Accordingly, the sealing resin does not flow around the back surface of the lead, so that the mounting surface of the lead can be reliably exposed on the back surface of the sealing portion. As a result, it is possible to prevent the lead from slipping into the sealing portion, thereby preventing the formation of resin flash burrs on the mounting surface of the lead.

(6). In a peripheral-type semiconductor device, the protrusion of the lead slightly protruding from the side surface of the sealing portion faces the surface opposite to the semiconductor device mounting side of the sealing portion, so that the semiconductor device can be mounted on a mounting board or the like. When mounted on the lead, a gap can be formed between the vicinity of the tip of the mounting surface of the lead and the connection-side terminal. Accordingly, the solder is buried in the gap, so that the solder fillet can be formed high, and therefore, the connection reliability when mounting the semiconductor device can be improved.

[Brief description of the drawings]

FIGS. 1A, 1B, and 1C are diagrams showing an example of the structure of a semiconductor device (QFN) according to a first embodiment of the present invention, where FIG. 1A is a plan view and FIG. The side view and (c) are bottom views.

FIG. 2 is an enlarged sectional view showing the structure of the semiconductor device shown in FIG.

FIGS. 3A and 3B are cross-sectional views showing an example of an assembled state corresponding to main steps in the method of manufacturing the semiconductor device shown in FIG. 1; FIG. 3A is a view of a lead frame;
Is a wire bonding step.

4 (a), (b), and (c) are cross-sectional views showing an example of an assembled state corresponding to main steps in the method of manufacturing the semiconductor device shown in FIG. 1; The state before the mold clamping, (b) is the resin injection state after the mold clamping in the molding step, and (c) is the cutting step.

5A and 5B are diagrams showing an example of a structure and a mounting state of a semiconductor device (QFN) according to a second embodiment of the present invention, wherein FIG. 5A is a cross-sectional view of a QFN, and FIG. It is sectional drawing of a mounting state.

FIGS. 6A, 6B, and 6C are cross-sectional views illustrating an example of an assembled state corresponding to main steps in the method for manufacturing the semiconductor device illustrated in FIG. 5; FIG. b)
Represents a plating step, and (c) represents a cutting step.

FIGS. 7A, 7B, 7C, and 7D are cross-sectional views illustrating an example of an assembled state corresponding to main steps of a semiconductor device manufacturing method according to a modified example of the semiconductor device manufacturing method of the present invention; (A) is a molding step, (b) is a plating step,
(C) is a cutting step, and (d) is a mounting state.

FIGS. 8A, 8B, 8C, and 8D are cross-sectional views showing an example of an assembled state corresponding to main steps of a semiconductor device manufacturing method according to a modified example of the semiconductor device manufacturing method of the present invention; (A) is a molding step, (b) is a plating step,
(C) is a cutting step, and (d) is a mounting state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead frame 1a Lead 1b Tab 1c Chip support surface 1d Mounting surface 1e Tab suspension lead 1f Bonding surface (opposite surface) 1g Projection 1h Depression 1i Side surface 2 Semiconductor chip 2a Pad (surface electrode) 2b Main surface 2c Back surface 3 Sealing part 3a Back surface (surface on the semiconductor device mounting side) 3b Side surface 3c Surface 4 Wire (connecting member) 5 QFN (semiconductor device) 6 Mold 6a Upper mold (second mold) 6b Lower mold (first Mold 6c Cavity 6d Cavity forming surface 6e Clamp surface 6f Convex portion 6g Small convex portion 7 Resin for sealing 8 Mounting substrate 8a Board side terminal 9 Solder 10 Solder plating layer 11 Solder fillet 12 Die bond material

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshihiko Shimanuki 3274, Yagibashi Higashi, Hanazawa, Yonezawa, Yonezawa, Yamagata Prefecture F-term (reference) 5F061 AA01 CA21 EA02 EA03 5F067 AA01 AA09 BC11 DE05 DE14

Claims (5)

[Claims] 1. A resin-sealed semiconductor device, comprising: a tab for supporting a semiconductor chip; a sealing portion formed by resin-sealing the semiconductor chip; and a semiconductor device mounting side of the sealing portion. A mounting surface that is exposed on the surface of the semiconductor device, and a protrusion that slightly protrudes from a side surface of the sealing portion, and the protrusion faces a surface of the sealing portion opposite to a surface on the semiconductor device mounting side. A plurality of leads, and a connection member for connecting a surface electrode of the semiconductor chip and the corresponding lead. 2. A method of manufacturing a resin-encapsulated semiconductor device, comprising: a tab for supporting a semiconductor chip; and a mounting surface exposed on a surface of the sealing portion on the semiconductor device mounting side when the resin is sealed. Providing a lead frame having a plurality of leads bent toward the mounting surface side; joining the tab of the lead frame to the semiconductor chip; and a surface electrode of the semiconductor chip. Connecting the lead of the lead frame with the lead by a connecting member, and forming a cavity corresponding to the semiconductor device mounting side surface of the mold by molding the lead by bending the lead. Clamping the mold by closely adhering to a surface; supplying sealing resin to a cavity of the mold to mount the lead; Forming the sealing portion so as to be exposed on the surface of the sealing portion on the semiconductor device mounting side, and sealing the semiconductor chip with a resin; and cutting and separating the lead from the lead frame. A method for manufacturing a semiconductor device, comprising: 3. A method of manufacturing a resin-encapsulated semiconductor device, comprising: a plurality of leads each having a tab for supporting a semiconductor chip and a mounting surface that can be exposed on a semiconductor device mounting side surface of a sealing portion. A step of preparing a lead frame having: a step of joining the tab of the lead frame to the semiconductor chip; and a connection member for connecting a surface electrode of the semiconductor chip and the corresponding lead of the lead frame. And a step of connecting the first and second molds in a mold including the first and second molds, wherein a clamp surface for clamping the lead is bent outward from the side of the cavity forming surface toward the concave side of the cavity. The lead frame is clamped by the clamp surface of the mold, and the mounting surface of the lead is brought into contact with the semiconductor device mounting side surface of the mold. Providing a sealing resin to the cavity of the mold and exposing the mounting surface of the lead to a surface of the sealing portion on the semiconductor device mounting side. Forming the sealing portion and sealing the semiconductor chip with a resin, and cutting and separating the lead from the lead frame. 4. A method of manufacturing a resin-encapsulated semiconductor device, comprising: a plurality of leads each having a tab for supporting a semiconductor chip and a mounting surface that can be exposed on a surface of the sealing portion on the semiconductor device mounting side. A step of preparing a lead frame having: a step of joining the tab of the lead frame to the semiconductor chip; and a connection member for connecting a surface electrode of the semiconductor chip and the corresponding lead of the lead frame. And connecting the lead frame by clamping the lead frame by the clamp surface of the mold, in which a convex portion for pressing a surface of the lead opposite to the mounting surface of the lead is provided on a clamp surface of the mold. The convex portion presses the surface of the lead on the side opposite to the mounting surface, so that the mounting surface of the lead corresponds to the semiconductor device mounting side surface of the mold. Providing a sealing resin to the cavity of the molding die so that the mounting surface of the lead is exposed to the semiconductor device mounting side surface of the sealing portion. Forming the sealing portion on the semiconductor chip and sealing the semiconductor chip with a resin; cutting the lead at a concave portion of the lead formed by the convex portion of the molding die, and removing the lead from the lead frame. Separating the semiconductor device. 5. A method for manufacturing a resin-encapsulated semiconductor device, comprising: a tab for supporting a semiconductor chip; and a mounting surface that is exposed on a surface of the sealing portion on the semiconductor device mounting side when the resin is sealed. Preparing a lead frame having a plurality of leads comprising: a step of joining the tab of the lead frame and the semiconductor chip; and a surface electrode of the semiconductor chip and the corresponding lead frame of the lead frame. A step of connecting the lead with a connecting member; and a step of connecting the lead to a clamp surface of a second mold facing a first mold having a cavity forming surface corresponding to the surface on the semiconductor device mounting side of the mold. A convex portion for pressing the surface opposite to the mounting surface is provided, and a small convex portion smaller than the convex portion for pressing the mounting surface of the lead is provided on the clamp surface of the first mold. The lead frame is clamped by the clamp surface of the mold die, and the mounting surface of the lead and the surface on the opposite side thereof are pressed by the convex portion and the small convex portion, thereby the mounting surface of the lead. Contacting the cavity with the cavity forming surface of the first mold, supplying a sealing resin to the cavity of the mold die, and mounting the lead on the semiconductor device mounting surface of the sealing portion. Forming the sealing portion so as to be exposed on the side surface and sealing the semiconductor chip with a resin; and forming the sealing portion with the concave portion of the lead formed by the convex portion and the small convex portion of the mold. Cutting the leads to separate the leads from the lead frame.