JP2822997B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a semiconductor device having an improved connection structure between a semiconductor element and internal leads and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, such a semiconductor device has a semiconductor element sealed inside a device main body, a terminal lead (external lead) led out from the device main body, and a semiconductor device which enters into the device main body from the terminal lead. , And an internal lead connected to the semiconductor element by a wire or the like.
However, in such a semiconductor device, in the state of the lead frame before being sealed with the resin, there is no boundary between the terminal lead and the internal lead.

[0003] Since information in the sealed semiconductor element is electrically input and output via the leads, the semiconductor element and the leads need to be electrically connected as described above.

FIG. 8 is a plan view of a lead connection portion of a semiconductor device for explaining an example of the related art. As shown in FIG. 8, the semiconductor device includes a semiconductor device 1 in which leads 3
In connecting the semiconductor element 1 having the pad (electrode) 24 formed on the upper surface to the lead 3, the lead 3 is extended to the pad 24 of the semiconductor element 1 and the tip end 25 of the lead is connected to the pad 24. The structure is directly pressed.

In this case, considering the size of the pad 24, it is necessary to reduce the width of the lead end portion 25. However, there is a limit to reducing the lead end portion 25 while keeping the plate thickness at a certain value or more. It's getting harder. Moreover,
Since the shape of the lead tip portion 25 must match the pad 24, it is necessary to prepare a new lead frame even if the pad 24 is minutely changed, or the lead itself is thin and the lead is likely to deform. There are drawbacks.

Therefore, in order to prevent such lead deformation, connection with a semiconductor element by wire bonding has been conventionally performed.

FIG. 9 is a plan view of a lead connection portion of a semiconductor device for explaining another conventional example. As shown in FIG. 9, such a semiconductor device is an example in which a lead 3 is connected to a semiconductor element 1 via a wire 5, and a pad 24 of the semiconductor element 1 and a tip of the lead 3 are bonded by a conductive wire 5. Structure. As a material of the wire 5, an alloy such as Au, Al, or Cu is used. If the wire 5 is not in contact with the wire 5, the wire 5 can be extended freely to some extent. Even if it is changed, the connection can be made without changing the lead frame.

The relationship between the lead frame and wire bonding is as shown in FIG.

FIG. 10 is a plan view of a lead frame of the semiconductor device shown in FIG. As shown in FIG. 10, the lead frame 27 connects the semiconductor element 1 on the island 6 and the leads 3 by wires.
The semiconductor element 1 and the internal leads 3 are connected to prevent disconnection.
Must be fixed. That is, when performing bonding by wire, the semiconductor element 1 is mounted (adhered) to the island 6 integrated with the lead 3.

The wire bonding generally includes ball bonding and wedge bonding, and these will be described below.

FIG. 11 is a schematic view of a ball bonding apparatus for explaining an example of a conventional method of manufacturing a semiconductor device. As shown in FIG. 11, the ball bonding apparatus (ball bonder) includes an air tension 29 for applying tension so that the wire 5 drawn from the reel 28 is not loosened, and a clamp for holding and feeding the wire 5. 30 and is sent out from a capillary 31 that guides the wire 5. The capillary 31 is fixed to the arm 33 together with the clamp 30, and is set so as to be movable on the lead frame 27. The wire 5 sent out from the capillary 31 is melted by the torch 32.

FIGS. 12A to 12D are schematic cross-sectional views of a ball bonding apparatus shown in the order of steps for explaining the ball bonding procedure in FIG.
First, as shown in FIG. 12A, the wire 5 is sent out from the tip of the capillary 31.

Next, as shown in FIG. 12B, when a voltage is applied to the torch 32, a spark is generated, and the heat melts the wire 5 to form a ball 34.

Next, as shown in FIG. 12C, the ball 34 is pressed against a pad on the semiconductor element 1 by a capillary 31 and thermocompression-bonded.

Thereafter, as shown in FIG. 12D, while pulling out the wire 5 from the capillary 31, the capillary 31 is moved to the intended lead 3, and
Thermocompression bonding. Further, the capillary 31 is lifted, the wire 5 is cut, and an appropriate amount of the wire 5 is put out so that a ball can be formed, and the wire 5 is returned to the state shown in FIG.

When the capillary 31 is vibrated using ultrasonic waves when the wire 5 is thermocompression-bonded to the pad or the internal lead 3 of the semiconductor element 1, the adhesion of the wire 5 is improved.

In the above-described ball bonding, since the ball 34 is formed at the tip of the wire 5, it is necessary to separate the adjacent wire 5 by at least the distance of the ball. To solve this problem, wedge bonding that does not require a ball has been proposed.

FIG. 13 is a cross-sectional view of a wire shape in wedge bonding for explaining another example of a conventional method of manufacturing a semiconductor device. As shown in FIG. 13, in this wedge bonding, the width of the wire 5 connecting the semiconductor element 1 and the lead 3 is set to be smaller than the diameter of the ball described above.

FIGS. 14A and 14B are cross-sectional views of capillaries in various types of bonding. First, as shown in FIG. 14A, in this case, a capillary 31 for ball bonding is shown.
Has a structure in which the ball 34 is pressed and thermocompression-bonded to a pad or a lead.

On the other hand, as shown in FIG. 14B, in this case, a capillary 31 for wedge bonding is shown.
The capillary 31 presses the wire 5 from the side.

When these two are compared, in the ball bonding, bonding can be performed in any direction (360 degrees), whereas in the wedge bonding, since the hole through which the wire 5 passes is formed obliquely, the wire 5 is inclined. Is limited to one direction.

Therefore, in the wedge bonding, the base for fixing the lead frame is rotated so that 36
0 degree bonding is enabled. However, in this wedge bonding, since the lead frame fixing base is rotated, the lead frame itself cannot be enlarged.

In short, in wire bonding,
For a target such as a lead frame, which is difficult to rotate, ball bonding is used and a single body such as a ceramic package is handled. In addition, wedge bonding is used for an object that can be easily rotated.

In both cases of ball bonding and wedge bonding, the wire is pressed from above, so that both the semiconductor element and the lead must be connected to the same upper surface by a wire. In addition, the presence of the wire 5 causes the lead 3 to be thicker by the wire 5 inside the semiconductor device.

[0025]

In the above-described conventional semiconductor device and the method of manufacturing the same, since the pads of the semiconductor element and the leads are sealed with the resin in a bonded state, the semiconductor device having the island structure or the leads can be used. Lead-on-chip (L) placed on a semiconductor element via an adhesive tape
Not only in the OC) structure, but the member located at the highest position when viewed in cross section is a wire.

By the way, as a method of drawing a product name on the surface of a semiconductor device, the conventional marking with ink is performed by a laser on the resin surface due to the restriction on the use of an organic solvent used as a pretreatment for the marking. It has been switched to a stamping method that scrapes away. As a result, the resin on the surface of the device is shaved, and if the above-mentioned wire is particularly high, there is a risk that the wire is exposed or cut by the laser.

In order to prevent the wire from being exposed or cut, it is effective to reduce the height of the wire itself. In particular, in a semiconductor device having a LOC structure, the height of the internal lead bonded to the wire is reduced. Since it hardly changes, the height of the wire cannot be further reduced.

Therefore, in the conventional semiconductor device and the method of manufacturing the same, the risk of exposing and cutting the wires cannot be reduced, and at the same time, the thickness of the resin cannot be reduced to reduce the thickness of the entire device. There is a disadvantage that.

In the conventional semiconductor device and its manufacturing method, when bonding on a lead frame, the lead frame is exposed to a high temperature for a time proportional to the number of wires to be bonded. Oxidation of each member progresses due to this high temperature state. Oxidation of a semiconductor element mainly composed of Si or a wire mainly composed of Au is not particularly problematic compared to oxidation of a lead frame. Many easily oxidizable materials such as alloys are used.

Therefore, when the lead frame is oxidized, the adhesion between the resin and the frame is deteriorated, and cracks occur in the package body from peeling, resulting in a deterioration in quality.

An object of the present invention is to reduce the risk of exposure and cutting of such wires, reduce the thickness of the resin, increase the adhesion between the frame and the resin, and improve the reliability of the semiconductor device. It is to provide a manufacturing method.

[0032]

According to the present invention, there is provided a semiconductor device comprising:
In a semiconductor device, a semiconductor element and an internal lead electrically connected to the semiconductor element by a conductive wire are sealed in a package body, and a terminal lead connected to the internal lead is led out from the package body. A pad on the upper surface of the semiconductor element and a lower surface of the internal lead are electrically connected by the conductive wire.

Further, the method for manufacturing a semiconductor device according to the present invention
A first step of bonding and connecting the upper surface of the semiconductor element and the dummy lead with a conductive wire, and reconnecting an intermediate part of the connected conductive wire to an internal lead, and cutting an excess of the conductive wire; And removing the dummy lead together with the second step.

Further, in the first step of the method of manufacturing a semiconductor device according to the present invention, an element fixing groove is formed in the center, and a projection for guiding the conductive wire is formed outside the element fixing groove. Using a jig provided with a dummy lead fixing portion for fixing the dummy lead at both ends, the jig is formed so as to connect the semiconductor element and the dummy lead.

Further, a method of manufacturing a semiconductor device according to the present invention
A first step of bonding and connecting the upper surface of the semiconductor element and the conductive thin film formed on the upper surface of the insulating thin plate with a conductive wire, and attaching the conductive thin film together with the conductive wire to an internal lead; And a second step of making an electrical connection between the conductive wire and the internal lead.

[0036]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view for explaining an embodiment of the semiconductor device of the present invention. As shown in FIG. 1, this embodiment is an example of a semiconductor device having an island structure, in which a pad formed on an upper surface 2 of a semiconductor element 1 mounted on an island 6 and a lower surface 4 of a lead 3 are wired. 5 is a bonding connection. Normally, the wire 5 is connected to the upper surface of the lead 3. In the present embodiment, one end of the wire 5 is connected to the lower surface 4 of the lead in order to lower the height position of the wire 5. As a result, the thickness of the resin for sealing the whole can be reduced.

FIG. 2 is a sectional view for explaining another embodiment of the semiconductor device of the present invention. As shown in FIG.
This embodiment is an example of a semiconductor device having a LOC structure, in which a semiconductor element 1 is bonded via a polyimide tape 7 and a pad formed on an upper surface 2 of the element and a lower surface 4 of a lead 3 are connected by wires 5. Bonded. Also in this case, the wire 5 is normally connected to the upper surface of the lead 3, but one end of the wire 5 is connected to the lower surface 4 of the lead. Thereby, the wire 5
At the same time, the height of the resin is lowered and the thickness of the resin is reduced.

As described above, the island structure (FIG. 1) and the L
Although the connection position of the wire 5 to the lead 3 is lowered irrespective of the internal structure such as the OC structure (FIG. 2), a comparison between the two shows that the LOC structure in which the lead 3 is above the semiconductor element 1 than the island structure. Is more effective in lowering the height of the wire.

FIGS. 3A and 3B are a perspective view and a sectional view taken along line AA 'of the jig used in the method of manufacturing a semiconductor device according to the present invention, respectively. First, as shown in FIG. 3A, in manufacturing the semiconductor device of FIGS. 1 and 2 described above, the present embodiment uses a jig 8 for connecting a conductive wire to the lower surface of a lead. In this method, a conductive wire is once bonded and connected between a semiconductor element and a dummy lead, which will be described later, and then a part of the connected conductive wire is reconnected to an internal lead. The jig 8 has an element fixing groove 9 formed at the upper center for fixing a semiconductor element, and a projection 10 for projecting obliquely inward from both sides of the element fixing groove 9 and for pressing and cutting a wire. Are formed at both ends on the outside of the element fixing groove 9 and the projections 10 and one step lower, and include a dummy lead fixing portion 11 for installing a dummy lead.

Further, as shown in FIG.
Is pressed by a lid 13 via a spring 12. For this reason, a structure is employed in which the projection 10 slides toward the dummy lead when pressed from above.

FIG. 4 is a plan view of a temporary connection portion of the semiconductor device using the jig in FIGS. 3A and 3B. As shown in FIG. 4, first, the semiconductor element 1 and the dummy lead 14 are attached to the jig 8. After that, the wire 5 is
Over the pad of the semiconductor element 1 and the dummy lead 14.
And bonded to it. Here, the dummy lead 14
The connection to the side is a temporary connection. When the lead 3 is placed on the semiconductor element 1, the range (area) where the lead exists
15 is as shown by the dotted line, so that the lead 3 and the projection 1
It is necessary for the wire 5 to pass through the position where 0 crosses.
The condition is that the wires 5 are bonded to all necessary pads, and all the connections are performed simultaneously. The procedure of the main connection, that is, the step of connecting the wire 5 to the lead 3 after bonding the dummy lead 14 and the semiconductor element 1 will be described with reference to FIG.

FIGS. 5A to 5D are cross-sectional views of a semiconductor device and a jig shown in the order of steps for explaining one example of a method of manufacturing a semiconductor device according to the present invention. First, as shown in FIG.
And the dummy lead 14 are fixed, and a wire 5 is
Bonding connection once. At this time, wire 5
Is adjusted so as to contact the projection 10.

As shown in FIG. 5B, a lead (frame) 3 provided on the lower surface with a polyimide tape 7 for bonding to the semiconductor element 1 is moved from above by a lead frame presser 16. At this time, the wire 5 is pressed by the wire presser 17 to prepare for cutting.

Next, as shown in FIG. 5C, the lead (frame) 3 is adhered (mounted) to the semiconductor element 1 by the lead frame retainer 16 and sandwiched between the dummy lead 14 by the wire retainer 17. The wire 5 is pressed against the lower surface of the lead 3 by the projection 10 of the jig 8. Thereafter, the protrusion 10 retracts and slides, so that the extra removal wire 18 on the dummy lead 14 side is used.
Is disconnected.

Further, as shown in FIG. 5D, when the frame retainer 16 is released and the semiconductor element 1 is taken out together with the leads 3, the wire retainer 17 becomes excessively removed.
8 is held down by the dummy lead 14, so that only the necessary portion can be taken out without the removal wire 18 remaining on the lead 3.

Here, the step of changing the temporary connection to the main connection also serves as the mounting of the semiconductor element 1, and all the wires 5 are simultaneously bonded. Thus, heating of the lead frame during mounting and bonding is minimized, and as a result, oxidation of the lead frame is minimized.

In the above-described embodiment of the manufacturing method shown in FIGS. 5A to 5D, since the wire 5 bonded to the dummy lead 14 is cut and removed, the cutting and removing steps are complicated. Become. Therefore, an example in which the dummy lead itself is improved will be described below.

FIGS. 6A and 6B are a plan view and a sectional view of a lead connection portion for explaining another example of the method of manufacturing a semiconductor device according to the present invention. As shown in FIG. 6A, the present embodiment is a method for manufacturing a semiconductor device having a LOC structure, in which a polyimide tape 19 provided with a conductive pattern 20 is used in place of the dummy lead described above. is there. The polyimide tape 19 is provided so that the conductive patterns 20 are exposed at a pitch corresponding to the interval between the leads 3 arranged in the lead existing range 15, and the polyimide tape 19 is directly attached to the lower surface of the lead 3. You.

As shown in FIG. 6B, a layer of solder 21 is provided on the back surface of the lead 3 in this case. In particular, the solder 21 is applied in the form of a solder paste made by kneading a granular solder and a solvent to a portion of the lead 3 that comes into contact with the conductive pattern 20, and the thickness of the solder 21 is smaller than the diameter of the wire 5. Also keep it thick. First, the semiconductor device 1 has a wire 5
Is connected by bonding to the conductive pattern 20 formed on the polyimide tape 19. Then, the lead 3 and the polyimide tape 19 are superimposed and heated and cooled, so that the molten solder 21 fixes the lead 3 and the conductive pattern 20.

As a result, the lead 3 and the conductive pattern 20
The wire 5 is sandwiched between them, and the wire 5 and the lead 3 are electrically connected.

However, unlike a semiconductor device having an LOC structure in which the semiconductor element 1 is attached to leads from below as described above, in a semiconductor device having an island structure, it is necessary to change the semiconductor element 1 from the jig 8 to the island 6. It is difficult because the wire 5 is deformed. In the case of a semiconductor device having such an island structure, a frame structure as shown in FIG. 7 is improved.

FIGS. 7A and 7B are plan views of a lead portion and an island portion for explaining a method of manufacturing a semiconductor device employing an island structure in the present invention. As shown in FIGS. 7A and 7B, in the semiconductor device having such an island structure, separate frames including a frame 22 on which the leads 3 are formed and a frame 23 on which the islands 6 are formed are prepared. First, in manufacturing, the semiconductor element is mounted on the island 6 and placed on a jig, and then a wire is bonded to a dummy lead, and then the lead 3 is connected. At this time, bonding is enabled by combining the leads 3 with the frames 22 and 23 of the island 6.

That is, after the semiconductor element is mounted on the island 6 of the frame 23, the semiconductor element is mounted on the jig so that the island 6 is fixed. Next, after the semiconductor element and the dummy lead are wire-bonded, the frame 22 is aligned and overlapped from above the jig. Finally, the bonding is completed by replacing the wire with the lead 3.

As described above, in the semiconductor device of the present embodiment, the pad on the upper surface of the semiconductor element and the lower surface of the internal lead are connected by the wire.

In manufacturing such a semiconductor device, a first step of connecting a wire between a semiconductor element and a dummy lead and a second step of reconnecting a part of the connected wire to the lower surface of the internal lead are performed. And steps are required.

[0057]

As described above, in the semiconductor device of the present invention, the height of the wire can be reduced by changing the connection position of the wire to the lead from the upper surface to the lower surface, thereby preventing the wire from being exposed. In addition, there is an effect that the thickness of the device itself can be reduced.

The method of manufacturing a semiconductor device according to the present invention
Adopting two connection processes using dummy leads, etc., can reduce the time required for the lead frame to be exposed to high temperatures, thereby suppressing oxidation of the lead frame and increasing the adhesion between the lead frame and the resin. And the reliability of the device itself can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating one embodiment of a semiconductor device of the present invention.

FIG. 2 is a cross-sectional view for explaining another embodiment of the semiconductor device of the present invention.

FIG. 3 is a diagram illustrating a perspective view of a jig used in a method of manufacturing a semiconductor device according to the present invention and a cross section taken along line AA ′ thereof.

FIG. 4 is a plan view of a temporary connection portion of the semiconductor device using the jig in FIGS. 3A and 3B.

FIG. 5 is a cross-sectional view of a semiconductor device and a jig and tool shown in the order of steps for collectively explaining an example of a method of manufacturing a semiconductor device according to the present invention.

FIG. 6 is a diagram showing a plan view and a side cross section of a lead connection portion for explaining another example of the method for manufacturing a semiconductor device of the present invention.

FIG. 7 is a plan view of a lead portion and an island portion for describing a method of manufacturing a semiconductor device employing an island structure in the present invention.

FIG. 8 is a plan view of a lead connection portion of a semiconductor device for explaining an example of the related art.

FIG. 9 is a plan view of a lead connection portion of a semiconductor device for explaining another example of the related art.

10 is a plan view of a lead frame of the semiconductor device shown in FIG.

FIG. 11 is a schematic view of a ball bonding apparatus for explaining an example of a conventional method for manufacturing a semiconductor device.

12 is a schematic cross-sectional view of the ball bonding apparatus shown in the order of steps for explaining the ball bonding procedure in FIG.

FIG. 13 is a cross-sectional view of a wire shape in wedge bonding for explaining another example of a conventional method for manufacturing a semiconductor device.

FIG. 14 is a sectional view of a capillary in various types of bonding.

[Description of Signs] 1 Semiconductor element 2 Element upper surface 3 Lead 4 Lead lower surface 5 Wire 6 Island 7 Polyimide tape 8 Jig and tool 9 Element fixing groove 10 Projection 11 Dummy lead fixing part 12 Spring 13 Cover part 14 Dummy lead 15 Lead existing range 16 Lead Frame Holder 17 Wire Holder 19 Polyimide Tape 20 Conductive Pattern 21 Solder 22 Lead Frame 23 Island Frame

Claims (4)

(57) [Claims] A semiconductor device and an internal lead electrically connected to the semiconductor device by a conductive wire are sealed in a package body, and a terminal lead connected to the internal lead is placed outside the package body. In a semiconductor device to be derived, a pad on an upper surface of the semiconductor element and a lower surface of the internal lead are electrically connected by the conductive wire. A first step of bonding and connecting the upper surface of the semiconductor element and the dummy lead with a conductive wire; reconnecting a part of the connected conductive wire to an internal lead; Cutting the conductive wire and removing the conductive wire together with the dummy lead. 3. In the first step, an element fixing groove is formed in the center, a projection for guiding the conductive wire is formed outside the element fixing groove, and the dummy leads are fixed to both ends outside the projection. 3. The method of manufacturing a semiconductor device according to claim 2, wherein the connection between the semiconductor element and the dummy lead is performed using a jig provided with a dummy lead fixing portion. 4. A first step of bonding and connecting an upper surface of a semiconductor element and a conductive thin film formed on an upper surface of an insulating thin plate with a conductive wire, and bonding the conductive thin film together with the conductive wire. A second step of attaching to the internal lead and electrically connecting the conductive wire to the internal lead.