JP3134858B2 - Method of assembling semiconductor device and semiconductor device manufactured by the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for assembling a semiconductor device, and more particularly, to a method for assembling a semiconductor device which enables normal mounting of a small semiconductor chip.

[0002]

2. Description of the Related Art In recent years, semiconductor devices have been reduced in size due to cost reduction and miniaturization. In a semiconductor device having a light transmission window, in particular, in a solid-state imaging device or the like, there is a remarkable tendency to reduce the size. In particular, in solid-state imaging devices equipped with linear image sensors used in facsimile machines and image scanners, the chip width is about the same as or smaller than the chip thickness, requiring high assembly technology. I have. Such a semiconductor chip has, for example, a length of 35 mm and a width of 0.35 m.
m and a thickness of about 0.4 mm.

FIG. 8A is a perspective view showing an example of a solid-state imaging device using a ceramic for a case (device frame). FIG. 8B is a cross-sectional view of the solid-state imaging device illustrated in FIG. 8A taken along line AA and cut perpendicular to the surface of the solid-state imaging device. FIG. 8A does not show the transparent cap 110 shown in FIG. 8B.

As shown in FIG. 8, a case comprises a ceramic base 101 and a frame 102, and internal leads 104.
And a lead frame composed of the external lead 103 and a frit glass 114 therebetween.

A chip (semiconductor chip) 108, which is a linear image sensor, is mounted on a flat mounting surface 105 of a case by a mounting material (adhesive) 11 in a mounting process.
2 glued.

When the small chip 108 as described above is bonded to the mounting surface 105, the chip 108 divided into one chip unit is mounted on the mounting collet 1 as shown in FIG.
At 16, suction is performed by vacuum suction or the like, and the mounting surface 105 is sucked.
Glue to

Thereafter, in a bonding step, bonding pads on chip 108 and predetermined internal leads 1 are formed.
04 are connected by a bonding wire 109 formed of gold, aluminum, a copper alloy, or the like.

Then, a transparent cap 110 made of glass or transparent resin is adhered to the case with an adhesive 111, and the chip 108 is sealed in the case.

However, in the above case, when the ceramic is fired, the ceramic shrinks and the mounting surface 105 is warped. Due to the warpage of the mounting surface 105, the chip 108 is fixed to the mounting surface 105 in an inclined manner, which causes an image to be blurred in the optical system device and causes a deterioration in image quality.

In order to solve this problem, Japanese Patent Laid-Open Publication No.
In the technique disclosed in Japanese Patent No. 83660, the chip mounting surface is flattened by a mechanical grinding method, and the chip is fixed with an adhesive (mounting material).

A technique for providing a step portion (through hole 115) for inserting the chip 108 on the mounting surface 105 in order to improve the accuracy of the mounting position of the chip is disclosed in Japanese Patent Application Laid-Open No. 64-22035. Have been.

FIG. 10A is a perspective view of a solid-state imaging device having a through-hole 115 formed in a mounting surface 105, which is cut along the longitudinal direction of a chip 108 and perpendicular to the surface of the solid-state imaging device. . FIG. 10B shows the chip 10.
FIG. 9 is a cross-sectional view of the solid-state imaging device cut along a plane perpendicular to 8. In this solid-state imaging device, the mounting surface 105 is formed by a lead frame.

As shown in FIG. 10, a through hole 115 slightly larger than the chip 108 is provided as a step in a portion of the mounting surface 105 where the chip 108 is mounted, and the chip 108 is inserted into the through hole 115. The inserted chip 108 is fixed by the mount material 112. In this case, since the through-hole 115 is provided in the lead frame, when the thickness of the lead frame is 250 μm, the depth of the through-hole 115 is 250 μm or more.

However, as described above, in order to provide the through hole 115, the mounting surface 105 must be wider than the through hole 115. Therefore, there is a problem that the entire apparatus becomes large.

In addition to the above, another technique for improving the accuracy of the chip mounting position is disclosed in Japanese Patent Application Laid-Open No. HEI 2-112280.

In this technique, the mounting surface of the chip is formed of a metal plate independent of the case, and a metal projection for positioning is formed on the metal plate. The chip is arranged along the metal projection, and the relative position between the metal plate and the case is adjusted to improve the positional accuracy of the chip.

However, even in this technique, since the metal projection is formed on the mounting surface of the chip, there is a problem that the entire device becomes large accordingly.

In order to solve such a problem that the device becomes large, the technology disclosed in Japanese Patent Publication No. Hei 7-24296 discloses a U-shaped metal plate for improving the positional accuracy of the chip. It is provided so as to fit to both ends of the chip.

Cases using ceramics as described above are expensive. Therefore, in order to reduce the production cost, the case is being made of resin.
By using a resin for the case, it is possible to realize both cost reduction and weight reduction.

When the case is made of resin, if the lead frame is inserted into the center of the case mold in advance, the case shown in FIG.
As shown in FIG. 8, it can be formed in the same outer shape as the ceramic case shown in FIGS.

In this case, as in the case of the ceramic case, the chip 108 is connected to the flat mounting surface 105 of the case.
Is bonded with a mounting material 112. Then, in a bonding step, bonding pads on the chip 108 and predetermined internal leads 104 are connected by bonding wires 109 made of gold, aluminum, a copper alloy, or the like.
Then, a transparent cap 110 made of glass or transparent resin is used.
Is bonded with an adhesive 111, and the chip 108 is sealed in the case.

However, when a resin case is used, in an environment such as high temperature and high humidity, the resin may be deformed with time and the mounting surface 105 may be warped as illustrated in FIGS. When the mounting surface 105 is warped, about 50 mm at the center and both ends of the chip 108 in the longitudinal direction of the chip 108 due to the influence.
From 100 to 100 μm.

In an optical system device, such a chip 108
Warpage causes blurring of the image and causes deterioration of image quality.

Furthermore, as shown in FIG. 12, the chip 108 cannot withstand the warping stress of the mounting surface 105, and cracks 117 or breaks may occur, which lowers the reliability of the device. Such a problem also arises.

The cracks 117 are likely to occur when the mounting material 112 is not applied uniformly under the chip 108. In particular, as shown in FIG. 12, when the mounting material 112 is at both ends of the chip 108 and is not at the center, the chip 1
The stress is concentrated on the central portion of the part 08, and a crack 117 is generated.

When the mounting material 112 is uniformly applied under the chip 108 as shown in FIG. 13 to prevent the generation of such cracks 117, the chip 108 warps together with the warping of the mounting surface 105, and the stress is dispersed. As a result, the chip 108 does not crack. However, in this case,
Since the chip 108 is warped, the image quality is deteriorated as described above.

As a countermeasure against this warpage, as shown in FIG. 14, for example, a viscosity of 10,000 CPS (100 g / cm ·
The use of the low-stress mounting material 118 of 10 kg / m · sec or less reduces stress on the chip 108 due to warpage of the mounting surface 105, and
Warpage can be reduced.

[0028]

A small chip (semiconductor chip) having a chip width equal to or less than the chip thickness.
When mounting the chip, if the chip is tilted and sucked up by the mount collet, the chip tilts as shown in FIG.
There is a problem that the rollover may occur and the yield is reduced.

When a chip is small, if a through hole as shown in FIG. 10 is provided, more than half of the chip enters this through hole. In this case, depending on the application amount of the mounting material, the mounting material may crawl on the chip surface. If there is a mounting material or the like on the chip surface, there is a problem that an image is blurred in the optical system device.

Further, the through hole provided for improving the mounting position accuracy of the chip is larger in size than the chip, and as described above, if the chip is tilted and sucked into the mount collet, the chip may be tilted. There is a problem that it may roll over.

The U-shaped metal plate of the technique disclosed in Japanese Patent Publication No. 7-24296 only determines the position of the chip. Must be used. Therefore, when resin is used for the case, there is a problem that the chip may follow or crack may occur due to the warpage of the mounting surface as described above. In this case, there is a problem that even if a low-stress mounting material (adhesive) is used, it is only possible to reduce the warpage of the chip but not to eliminate it.

Accordingly, the present invention provides a method of assembling a semiconductor device which normally mounts a semiconductor chip by a simple method, improves the performance and reliability of the semiconductor device, and can reduce the manufacturing cost. And a semiconductor device manufactured by the method.

[0033]

In order to achieve the above object, a method of assembling a semiconductor device according to a first aspect of the present invention is a method of assembling a semiconductor device by mounting a semiconductor chip on a device frame. A first bonding step of bonding a plurality of flexible ribbons capable of supporting the semiconductor chip to the semiconductor chip; and the semiconductor chip having the ribbon bonded in the first bonding step. A second bonding step of setting the semiconductor chip at a predetermined position in the device frame, bonding the ribbon to a predetermined position in the device frame, and fixing the semiconductor chip.

According to the present invention, the plurality of ribbons can prevent the semiconductor chip from rolling over in the apparatus frame. Further, the semiconductor chip and the device frame can be fixed without using an adhesive. Therefore, the production cost of the semiconductor chip can be reduced without being affected by the warpage of the device frame or the like.

[0035] The first bonding step may include a step of bonding the plurality of ribbons to both ends of the semiconductor chip. By bonding the ribbon to both ends of the semiconductor chip, the semiconductor chip can be more firmly fixed.

[0036] The ribbon may be longer than the width of the semiconductor chip, and the first bonding step may include a step of bonding a central portion of the ribbon to the semiconductor chip.

The ribbon has conductivity, the first bonding step includes bonding the ribbon to a bonding pad of the semiconductor chip, and the second bonding step includes bonding the ribbon to the device. A step of bonding to a lead frame provided in the frame may be provided.

The ribbon is an anisotropic conductive film, and the first bonding step is to press a metal ball constituting the anisotropic conductive film to apply the anisotropic conductive film to the semiconductor chip. The second bonding step may include a step of pressing a metal ball forming the anisotropic conductive film and bonding the anisotropic conductive film to the lead frame.

The second bonding step may include a step of bonding the plurality of ribbons to the lead frame so that the plurality of ribbons come into contact with the outer periphery of the semiconductor chip. By bonding the ribbon so as to be in contact with the outer periphery of the semiconductor chip, the semiconductor chip can be more firmly fixed.

A semiconductor device according to a second aspect of the present invention is a semiconductor device manufactured by the method of assembling a semiconductor device according to the first aspect of the present invention. And a semiconductor chip mounted at the position and fixed to the device frame by a plurality of ribbons.

[0041]

Next, a method of assembling a solid-state imaging device according to a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a solid-state imaging device on which a chip (semiconductor chip) as a linear image sensor is mounted.

As shown in FIG. 1, a base 1 and a frame 2
(Device frame) is a case similar to the conventional case, and is formed of resin, ceramic, or the like.
An elongated chip 8 is mounted on the mounting surface 5 of this case. The width and thickness of the chip 8 are substantially the same, for example, 35 mm in length, 0.35 mm in width, and 0.4 mm in thickness.

The both ends of the chip 8 are fixed to the internal leads 4 by the ribbon 6. In addition, chip 8
(Not shown) and the internal leads 4 are connected by bonding wires 9.

The external lead 3 and the internal lead 4 are formed integrally according to the purpose, or formed separately and connected by a wire or the like.

When assembling such a solid-state imaging device, first, the ribbon 6 is bonded to the chip 8.

As shown in FIGS. 2A and 2B, a plurality of bonding pads 15 are formed on a certain surface of the chip 8. This bonding pad 15 is connected to the chip 8
May be formed on the electrodes described above, or may be newly provided for bonding the ribbon 6. And
As shown in FIGS. 2C and 2D, the ribbon 6 is bonded to the bonding pad 15. As shown in FIG. 2D, the ribbon 6 is connected to two electrodes (bonding pads 1).
In the case of bonding in 5), the two electrodes are at the same potential or are connected to the ground. If the two electrodes cannot be adhered to the same ribbon 6 because they are not at the same potential, the electrodes are shifted in advance to the position indicated by the arrow in FIG. 2D and are arranged as shown in FIG. I do.

When the ribbon 6 is bonded to the bonding pads 15 at both ends as shown in FIGS. 2C and 2D, the force applied to the ribbon 6 is smaller than when the ribbon 6 is bonded to the center. That is, when the ribbon 6 is bonded to both ends of the chip 8, the chip 8 can be more firmly fixed.
The ribbon 6 is bonded by being pressed by heat, ultrasonic waves, microwaves or the like depending on the material. The ribbon 6 is a solder ribbon, an aluminum ribbon, or the like.

When the ribbon 6 is bonded, the height from the surface of the chip 8 to both ends of the ribbon 6 is adjusted to be equal. The height of both ends of the ribbon 6 can be adjusted, for example, by bonding the flat ribbon 6 to the chip 8 and then bending the same by applying equal force to both ends, or adjusting the height from the bonded portion of the chip 8 to both ends of the ribbon 6. Is performed by shaping the ribbon 6 in advance so that the target height becomes the target height. Ribbon 6
Is performed by pressing the ribbon 6 with a mold or the like having a desired shape or sandwiching the ribbon 6 from above and below. By adjusting the height of both ends of the ribbon 6 as described above, when the chip 8 is fixed to the case, the chip 8
Can be suppressed from tilting with respect to the surface of the solid-state imaging device.

The thickness and width of the ribbon 6 are adjusted so that the two ribbons 6 bonded to both ends of the chip 8 have flexibility enough to support the weight of the chip 8.

Then, the chip 8 to which the ribbon 6 is adhered as shown in FIGS. 2C and 2D is sucked by vacuum suction or the like using a mount collet and placed on the mount surface, as in the conventional case. . However, in order to prevent the ribbon 6 from being largely deformed by the suction of the mount collet, a mount collet shorter than the chip 8 or having a shape as shown in FIG. 3 is used.

At the time of this installation, the chip 8
Since the ribbon 6 is adhered as shown in (c) and (d), the ribbon 6 can be prevented from being caught on the internal lead 4 and tilting or rolling over.

Thereafter, the chip 8 is mounted and fixed to the case by bonding the ribbon 6 bonded on the bonding pad 15 to the internal lead 4 of the case. The wires (bonding wires 9) of the bonding pads 15 other than both ends may be gold wires or aluminum wires as in the past.

As a method of fixing the chip 8 to the case, a method of making the height of the internal lead 3 close to the upper surface of the chip 8 as shown in FIG. 4A and a method of fixing the internal lead 3 as shown in FIG. There is a method of bringing the height of the chip 3 closer to the bottom surface of the chip 8. However, in order to increase the fixing strength of the chip 8, FIG.
(B) is more desirable. However, bonding pad 1
When the potential is different between the outer periphery of the chip 5 and the outer periphery of the chip 8 and it is desired to avoid electrical contact, a non-conductive ribbon is used, or an anisotropic conductive film described later is used.

In addition to the above, as shown in FIG. 4C, the ribbon 6 may be pulled with a certain force and adhered to the internal lead 4. In this way, a force for pressing the chip 8 against the mounting surface 5 acts, and the chip 8 can be more firmly fixed.

In the subsequent assembling, the transparent cap 10 is adhered to the upper surface of the case with an adhesive 11 as usual, and the case is sealed.

As described above, the ribbon 6 adhered to both ends of the chip 8 eliminates chip inclination and rollover.

Further, since the chip 8 is fixed by the ribbon 6, the influence of the warpage of the mounting surface 5 can be reduced.

Next, a method for assembling a solid-state imaging device according to a second embodiment of the present invention will be described with reference to the drawings.

FIG. 5 is a perspective view of a solid-state imaging device equipped with a chip (semiconductor chip) which is a linear image sensor.

The configuration of this solid-state imaging device is the same as that of the solid-state imaging device shown in the first embodiment, except that an anisotropic conductive film is used for the ribbon 6. FIG. 6 (a)
FIG. 2 is a sectional view of the anisotropic conductive film. This anisotropic conductive film is obtained by sandwiching a metal ball 12 with an insulating film 13 and forming a conductive film 14 on one surface of the insulating film 13.

The material of the metal ball 12 is various materials which can be press-bonded to the bonding pad 15 and the internal lead 4, for example, aluminum. The size of the metal ball 12 may be any size that matches the size of the bonding pad 15 and the width of the internal lead 4, and is, for example, about 50 to 100 μm.

When bonding such a ribbon 6 to the chip 8 or the like, the ribbon 6 is placed at a predetermined position on the chip 8 so that the insulating film 13 contacts the chip 8. Then, when the metal ball 12 is pushed by the protrusion from the conductive film 14 side, as shown in FIG. 6B, the insulating film 13 in that portion is broken, and the anisotropic conductive film and the bonding pad 15 or the internal lead of the case are broken. 4 adheres.

As described above, on the surface other than the crimping portion 7, the chip 8 and the ribbon 6 are electrically insulated by the insulating film, and the bonding pad 15 on the chip 8 and the internal lead 4 are electrically connected to each other. The wiring is formed by the conductive film 14 on the surface of the conductive film. If the insulating film 13 and the conductive film 14 are transparent, the metal balls 12 can be confirmed from the outside, and the alignment becomes easy. The metal balls 12 covered with the insulating film 13 of the anisotropically conductive film may be electrically connected to each other. In this case, the conductive film 14 on the surface of the anisotropically conductive film is unnecessary. Become.

The bonding pads 15 other than both ends of the chip 8 and the internal leads 4 are wired by bonding wires 9 such as gold wires or aluminum wires as in the conventional case. However, even if the above-described anisotropic conductive film is used. Good.

As shown in FIG. 5, the ribbon 6 'other than the both ends of the chip 8 is
5 and only one internal lead 14 may be connected.

As described above, even if the anisotropic conductive film is used for the ribbon 6, the inclination and rollover of the chip 8 can be eliminated and the influence of the warpage of the mounting surface 5 can be reduced.

The ribbons shown in the first and second embodiments can be stably mounted not only at two places at both ends of the chip but also at the center of the chip and other parts in the same manner. be able to.

Further, the bonding of the ribbon is not limited to both ends of the chip. If the chip can be fixed to the case while preventing the chip from tilting or rolling over, for example, a two-character like X is used.
Various methods are possible, such as crossing book ribbons and bonding them to the center of the chip.

Even if the cross section of the semiconductor chip shown above is not a square or a rectangle but a trapezoid, etc., the semiconductor chip can be fixed stably if the ribbons are adhered to both ends as described above. Can be.

Also, the ribbon is not one ribbon, but two ribbons.
As shown in FIG. 7, a book ribbon may be used. In this case as well, it is possible to prevent the semiconductor chip from rolling over, but it is desirable to support the semiconductor chip with one ribbon in view of the strength of the ribbon and the like.

When the chip 8 is fixed with the ribbon 6,
The chip 8 may be slightly lifted and fixed so that the bottom surface of the chip 8 does not contact the mounting surface 5. In this case, the chip 8 is less likely to be affected by deformation of the case.

[0073]

As is apparent from the above description, according to the present invention, a small semiconductor chip can be installed in a device frame (case) without tilting or rolling over by means of a ribbon having both ends adhered. it can. Therefore, the performance and reliability of the semiconductor device can be improved by a simple method, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a solid-state imaging device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of bonding a ribbon to a chip.

FIG. 3 is a view showing a shape of a mount collet.

FIG. 4 is a cross-sectional view of the solid-state imaging device.

FIG. 5 is a perspective view of a solid-state imaging device according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of the anisotropic conductive film.

FIG. 7 is a diagram illustrating another solid-state imaging device.

FIG. 8 is a diagram showing a conventional example of a semiconductor device.

FIG. 9 is a diagram showing a state in which a chip is sucked by a mount collet.

FIG. 10 is a diagram showing another conventional example of a semiconductor device.

FIG. 11 is a diagram showing a semiconductor device when a resin is used for a case.

FIG. 12 is a diagram showing the influence of a chip on warpage of a mounting surface.

FIG. 13 is a diagram showing the influence of a chip on the warpage of the mounting surface.

FIG. 14 is a diagram showing the influence of a chip on the warpage of the mounting surface.

FIG. 15 is a diagram showing a mounted state of a chip according to a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Frame 3 External lead 4 Inner lead 5 Mounting surface 6 Ribbon 6 'Ribbon 7 Crimp part 8 Chip 9 Bonding wire 10 Transparent cap 11 Adhesive 12 Metal ball 13 Insulating film 14 Conductive film 15 Bonding pad

Claims (7)

(57) [Claims] 1. A semiconductor chip is mounted on an apparatus frame.
A method for assembling a semiconductor device, comprising: a first bonding step of bonding a plurality of flexible ribbons capable of supporting the semiconductor chip and having flexibility to the semiconductor chip; and bonding the ribbon in the first bonding step. The bonded semiconductor chip is installed at a predetermined position in the device frame,
Gluing the ribbon at a predetermined position in the device frame,
A second bonding step of fixing the semiconductor chip. 2. The method according to claim 1, wherein the first bonding step includes a step of bonding the plurality of ribbons to both ends of the semiconductor chip. 3. The semiconductor device according to claim 1, wherein the ribbon is longer than a width of the semiconductor chip, and wherein the first bonding step includes a step of bonding a center portion of the ribbon to the semiconductor chip. A method of assembling the semiconductor device according to the above. 4. The ribbon has conductivity. The first bonding step includes a step of bonding the ribbon to a bonding pad of the semiconductor chip. The second bonding step includes bonding the ribbon. 4. The method according to claim 1, further comprising a step of bonding to a lead frame provided in the device frame.
13. The method for assembling a semiconductor device according to any one of the preceding items. 5. The method according to claim 1, wherein the ribbon is an anisotropically conductive film, and the first bonding step is to press a metal ball constituting the anisotropically conductive film and to attach the anisotropically conductive film to the semiconductor. The second bonding step includes a step of pressing a metal ball constituting the anisotropic conductive film and bonding the anisotropic conductive film to the lead frame. The method for assembling a semiconductor device according to claim 1, wherein: 6. The method according to claim 1, wherein the second bonding step includes a step of bonding the plurality of ribbons to the lead frame such that the plurality of ribbons contact the outer periphery of the semiconductor chip. 6. The method for assembling a semiconductor device according to claim 1. 7. A semiconductor device manufactured by the method for assembling a semiconductor device according to claim 1, further comprising: a device frame; and a plurality of devices mounted at predetermined positions in the device frame. And a semiconductor chip fixed to the device frame by the ribbon.