JP2828075B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor device.

[0002]

2. Description of the Related Art In recent semiconductor devices, chip size has been reduced due to cost reduction and miniaturization of the device.
Semiconductor devices having light-transmitting windows, particularly solid-state imaging devices, have a remarkable tendency to downsize, and among them, solid-state imaging devices equipped with linear image sensors used in facsimile and image scanners, Due to the reduction in chip size, the chip width has become about the same as or smaller than the chip thickness, and requires a high assembly technique.

Here, a solid-state imaging device equipped with a linear image sensor will be described as an example.

FIG. 6A is a perspective view showing an example of a conventional solid-state imaging device using a ceramic case, in which a transparent cap is not shown. FIG. 6B is a cross-sectional view illustrating a solid-state imaging device using a ceramic case.

As shown in FIG. 6, a lead frame for integrally forming an internal lead 104 and an external lead 103 is sandwiched between a ceramic base 101 and a ceramic frame 102.
It was made by gluing it together by 14.

[0006] The linear image using this case
The sensor chip 108 is bonded to the flat mounting surface 105 of the case via a mounting material (adhesive) 112 in a mounting process. Next, in the bonding step, the pads on the chip 108 and the internal leads 1 of the lead frame are formed.
04 are connected by a bonding wire 109 made of gold, aluminum or a copper alloy.

Thereafter, a transparent cap 110 made of glass or transparent resin is adhered to the upper surface of the chip 108 with an adhesive 111, and the chip 108 is sealed in the case. At this time, the adhesive 11
1 is applied, or a portion of the outer periphery of the glass that comes into contact with the case is sealed with a thermosetting sealing resin (such as a sealer).

[0008]

However, in the technique shown in FIG. 6, a chip of an elongated linear image sensor, for example, a chip having a length of 35 mm, a width of 0.35 mm and a thickness of 0.3 mm is mounted on the plane of the mounting surface of the case. When a chip having a thickness of 0.4 mm is mounted, the following problem occurs.

That is, in the dicing step, the chips cut from the wafer into one chip units are shown in FIG.
As shown in (a) and (b), when the vacuum is sucked by the mount collet 116 and the chip 108 is adhered to the mount surface 105 of the case via the mount material 112, the chip 108 is tilted and sucked into the mount collet 116. If
As shown in FIG. 10, there is a possibility that the chip 108 may be tilted and mounted while being turned sideways, resulting in a problem that defective assembly occurs.

Japanese Patent Application Laid-Open No. 64-22035 discloses an example in which a step portion for inserting a chip 108 is provided on a mounting surface 105 to improve the mounting position accuracy of the chip as shown in FIG.

FIG. 7A is a perspective view showing a conventional solid-state imaging device using a ceramic case, and FIG. 7B is a sectional view of the same.

As shown in FIG. 7, a through hole 115 is provided as a step portion slightly larger than the semiconductor element in the island portion which is the mounting surface 105 of the lead frame.
The sensor chip 108 is fixed.

In this case, a through hole 115 is formed in the lead frame.
Is provided, the lead frame thickness is 250 μm
In this case, the depth of the hole for receiving the chip 108 through the through hole 115 is 2 including the thickness of the lead frame.
Since the depth dimension is more than half of the chip thickness, the amount of the mounting material 112 applied to the hole becomes large, and the extra mounting material 112 is used.
However, there is a concern that a problem may arise that the crawls up to the side surface of the chip 108 and further to the chip surface.

Further, in consideration of the mounting error of the lead frame, the size of the through hole 115 is larger than the size of the chip.
When 08 is tilted and sucked up, the chip is tilted and mounted, and in some cases, it may roll over.

Therefore, in such a method, it is difficult to guide a thin chip such as a linear image sensor through the through hole 115.

In the conventional cases shown in FIGS. 6 and 7, expensive ceramics are used. However, in recent years, in order to reduce the cost, it is necessary to convert the ceramic cases to resin cases. In addition, it is possible to reduce the weight by using resin.

In the case where the case is made of a resin to cope with this low cost, the lead frame is inserted into the center of the upper and lower molds for molding the case, the resin is injected into the mold, and as shown in FIG. And the outer shape similar to the ceramic case of FIG.

Thereafter, the chip 108 is bonded to the flat mounting surface 105 of the lead frame via a mounting material 112, and is connected by a bonding wire 109 made of gold, aluminum, or a copper alloy in a bonding step. Thereafter, a transparent cap 110 made of glass or transparent resin is provided on the upper surface of the chip of the case.
The chip 108 is bonded to the chip 2 with an adhesive 111, and the chip 108 is sealed in the case.

In the case of such a resin case, in an environment where bad conditions such as high temperature and high humidity are present, as shown in FIGS. Mounting surface 20
5 warps at the center and both ends of the chip with respect to the longitudinal direction of the chip, and the chip warps by about 50 to 100 μm. With a linear image sensor set in an optical system, an image is formed. The image is blurred, which causes deterioration of image quality.

Further, as shown in FIG.
When the mounting agent 108 is not applied to the center of the chip 108, the chip 108 cannot withstand the stress of the case warpage sufficiently, and there is also a reliability problem that a crack 117 enters or breaks at the center of the chip 108. Occurs.

In the case where the coating material 112 is scattered in the center of the chip 108 as shown in FIG. 12, when the chip 108 warps together with the warping of the mounting surface, it depends on the amount of warpage of the mounting surface 205. In the meantime, the stress is dispersed and the chip does not crack, but in this case, the chip 1
08 warpage causes image quality degradation as described above.

As a countermeasure against the chip warpage, as shown in FIG. 13, a low stress mount material 118 having a viscosity of 10,000 CPS or less is used, so that the mounting surface 20 is reduced.
It is conceivable to reduce the stress on the chip due to the warpage of No. 5 and reduce the chip warpage.

However, even when the low-stress mount material 118 is used, the effect is reduced if the mount material is unevenly applied at the center of the chip. Therefore, it is important to apply the mount material uniformly under the chip, but it is difficult to apply the mount material uniformly with a flat mount surface as in the conventional example.

As described above, in order to reduce the cost of the solid-state imaging device, the use of resin for the case is an essential condition. However, reducing the warpage of the resin case during production is achieved by preventing deterioration in image quality and improving yield. This is one of the important issues for cost reduction and reliability improvement.

An object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide a semiconductor device which can be manufactured at low cost, is easy to manufacture, and has a reduced weight.

[0026]

To achieve the above object, a semiconductor device according to the present invention is a semiconductor device in which a semiconductor element is hermetically housed in a hollow envelope body. A portion to which the semiconductor element is bonded has a pedestal portion, a lower edge support portion, and a groove. The pedestal portion supports the lower surface of the semiconductor element, and the lower edge support portion rises on both sides of the pedestal portion. Formed on the opposite side of the semiconductor device,
The groove is a recess formed in a region of the pedestal portion corresponding to the lower surface of the semiconductor element, and a mounting agent for bonding the lower surface of the element to the pedestal portion is applied. .

Further, the device has a collecting groove, which collects excess mounting agent leaking from the groove and prevents the mounting agent from creeping up to the side surface of the element.

The lower edge support is an inner wall of a recess formed surrounding the pedestal.

The lower edge support portion is a protrusion formed to stand up around the pedestal portion.

A part of the groove extends in the length direction of the lower surface of the semiconductor element.

[0031]

A groove is provided at both ends and a center of a pedestal portion supporting a lower surface of a semiconductor element, and a mounting material is applied in the groove,
The mounting material is spread uniformly over the entire lower surface of the semiconductor element.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a view showing a semiconductor device according to Embodiment 1 of the present invention. The semiconductor device shown in FIG. 1 is a solid-state device using a linear image sensor as a semiconductor element. It is intended for an imaging device, and is shown in FIG.
FIG. 1A is a perspective view showing a case of a solid-state imaging device, and FIG.
(B) is a perspective view showing the state where the linear image sensor was mounted on the case. FIG. 2 (a) shows FIG.
2B is a cross-sectional view taken along the line AA ′, and FIG. 2B is a cross-sectional view taken along the line BB ′ in FIG.

As shown in the figure, the solid-state imaging device as a semiconductor device according to the first embodiment of the present invention has a pedestal portion, a lower edge support portion and a base portion at a portion where a semiconductor element of an enclosure body is bonded. And a groove.

The envelope body as a case comprises a base 1 and a frame 2. The frame 2 surrounds the outer peripheral edge of the base 1 and rises upward to secure a space for mounting a semiconductor element on the surface side of the base 1. doing. Also frame 2
Is hermetically closed by a transparent cap 10.

A concave portion 6 is formed on the surface side of the base 1, a pedestal portion (hereinafter referred to as a mounting surface) 5 is formed in the concave portion 6, and a raised concave portion 6 on both sides of the mounting surface 5 is formed. The internal leads 4 are provided in a row on the shoulder, and the external leads 3 integrated with the internal leads 4 are provided between the base 1 and the frame 2 so as to protrude toward the rear surface of the base 1.

The mounting surface 5 is provided so as to slightly protrude from the bottom of the recess 6 so as to support the lower surface of the semiconductor element 8. Since a linear image sensor is used as the semiconductor element 8, the recess 6 and the mounting surface 5 extend in the length direction of the base 1 (FIG. 2).
(A)).

The dimension between the opposed inner side walls 6b, 6b of the recess 6 located on both sides of the mounting surface 5 is set to substantially match the width S ₁ of the linear image sensor 8. The inner walls 6b, 6b of the recess 6 are applied to the opposing lower edge side surfaces of the linear image sensor 8 supported on the mounting surface 5, and the linear image sensor 8 rolls over the mounting surface 5. It is designed to block. Here, in the first embodiment shown in FIGS. 1 and 2, the inner side walls 6 b, 6 b of the concave portion 6 are used as a lower edge supporting portion.

As shown in FIG. 2B, the length S ₂ of the concave portion 6 in the longitudinal direction has a margin in the linear image area.
It is set larger than the size of the sensor 8.

In the area of the mounting surface 5 corresponding to the lower surface of the linear image sensor 8, a plurality of grooves 7a are provided uniformly over both ends and the center of the mounting surface 5. A required amount of a mounting material 12 for bonding the lower surface of the linear image sensor 8 to the mounting surface 5 is applied.

A collecting groove 7b is provided so as to surround the outer periphery of the mounting surface 5, and the excess mounting material 12 leaking from the groove 7a and climbing up to the side surface of the element is collected in the collecting groove 7b.

Next, an elongated linear image sensor chip, for example, a chip having a length of 35 mm and a width of 0.3
A case where a chip having a thickness of 5 mm and a thickness of 0.4 mm is mounted on an envelope body as a case will be described.

The dimension between the inner wall 6b, 6b opposing the concave portion 6, linear image and from, for example, about 50μm greater width S ₁ of the sensor 8 is set so as to prevent overturning of the chip 8. Grooves 7b are formed on both sides of the mounting surface 5 in the longitudinal direction with a width of 20 to 50 μm, and grooves 7a are formed on the mounting surface 5 at equal intervals with a width of 50 to 200 μm. The mounting surface 5 is formed at a height of 100 to 250 μm.

In the case shown in FIG. 1, the lead frame is inserted into the upper and lower centers of the case mold and the resin is injected into the mold as in the conventional case. It can be made similarly to the resin case as shown in FIG.

The method of forming the mounting surface 5 in the concave portion 6 is as follows. When the mounting surface 5 is formed using a part of the lead frame, the mounting surface 5, the internal leads 4 and the dimple are provided in the state of the lead frame. The concave portion 6 is provided by forming a through hole in a lead frame as in a conventional example of a ceramic case. When the mount surface 5 is not formed of a lead frame as shown in FIG. 1, the concave surface 6 and the mount surface 5 are integrally formed of resin using a case mold.

The dimensional accuracy of the recess 6 and the mounting surface 5 depends on the accuracy of the mold for forming the case, and the size and depth of the grooves 7a and 7b are determined by the amount of the mounting material 12 applied and the adhesiveness of the chip 8. To determine.

The following manufacturing method is performed in the same manner as the conventional method, and a case can be manufactured as shown in FIG.

Next, the chip 8 of the linear image sensor is mounted on the mounting surface 5.

Conventionally, when a mounting material is transferred by a stamp, a large amount of the mounting material is applied to both ends in the longitudinal direction of the chip, and the amount of the central portion is reduced.

Therefore, in the case of the present invention, as shown in FIG. 2B, a plurality of grooves 7a are formed at the center and both ends of the mounting surface 5.
The mounting agent 12 is applied in the groove 7a, the mounting agent 12 is pressed down on the lower surface of the chip 8, and the mounting agent 12 is applied uniformly in the longitudinal direction of the chip. That is, when the chip 8 is placed on the mounting surface 5, the mounting material 12 is pressed on the lower surface of the chip 8 and spreads uniformly over the entire surface of the mounting surface 5, and the chip 8 is held by the mounting agent 12 held in the groove 7 a. Can be uniformly adhered to the mounting surface 5. Also, the excess mounting agent on the lower surface of the chip 8 can be reliably collected by the groove 7b as shown in FIGS. 1A and 2A, and the mounting material is prevented from rising from the chip side surface to the chip upper surface. I do. In addition, a concave portion 6 is formed on a side surface on the opposite lower edge side of the chip 8 supported on the mounting surface 5.
Of the chip 8 on the mounting surface 5 is prevented.

Therefore, regardless of the method of applying the mounting agent, the mounting agent can be uniformly applied to the mounting surface 5 on which the chip 8 is mounted.

In the manufacture of the solid-state imaging device after mounting the chip, the transparent cap 10 is adhered with an adhesive 11 to seal the chip in the same manner as in the prior art.

As described above, by forming the groove 7a in the mounting surface 5 of the case, the mounting agent 12 can be uniformly applied to the entire surface of the mounting surface 5, so that a low stress mounting material as shown in FIG. Even when the chip 8 is mounted on the resin case by using the 118, it is possible to prevent image quality deterioration due to chip warpage, which has been a problem in the past. In addition, it is possible to solve the problem of reliability such as cracking or breaking of the chip at the same time.

FIG. 3 is a view showing the shape of the groove 7a provided in the pedestal portion (mounting surface) 5. As shown in FIG. FIG. 3A is an enlarged view of the mounting surface 5 of FIG. 1, in which the groove 7a is formed in a rectangular shape, and in FIG. 3B, the shape of the groove 7a is formed in an arc shape. . In FIG. 3C, a long groove 7c is provided in the central portion of the mounting surface 5 along the longitudinal direction of the chip 8, and the mounting agent 12 is applied more uniformly over the entire central portion and both end portions of the mounting surface 5. I am able to do it. Further, in FIGS. 3A to 3C, the groove 7b is provided on the entire outer circumference of the mounting surface 5, but as shown in FIG.
The groove 7b may be provided in a part of the outer periphery of the.

Further, the shapes and structures of the mounting surface 5, the grooves 7a and 7b, the recesses 6 and the like are not limited to the illustrated embodiment, and various changes can be made.

(Embodiment 2) FIG. 4 is a perspective view showing a chip mounting surface according to Embodiment 2 of the present invention, and FIG. 5 is a sectional view showing a chip mounting portion according to Embodiment 2 of the present invention.

In the first embodiment shown in FIGS. 1 and 2, the inner side walls 6b, 6b of the concave portion 6 are used as the lower edge supporting portion. However, in the second embodiment shown in FIGS.
The protrusions 13 for chip guide are formed on both sides of the mounting surface 5 at 20 to 50 μm on both sides of the mounting surface 5 so as to cover the grooves 7b, for example. A plurality are formed at intervals of about 20 mm.

According to the second embodiment, the warpage of the chip can be reduced by providing the grooves 7a and 7b in the mounting surface 5, and when the chip 8 is mounted on the mounting surface 5 with an oblique inclination. In addition, the chip 8 is guided by the projection 13, so that the inclination and the overturn at the time of mounting the chip, which have conventionally been problems, can be prevented.

[0059]

As described above, according to the present invention, the mounting agent can be uniformly applied to the entire mounting surface by forming grooves on the mounting surface of the case using low-cost resin. Further, it is possible to solve the conventional problems of reliability such as a decrease in yield due to poor electrical characteristics such as image quality deterioration due to chip warpage, chip cracks and chip breakage.

Further, when the chip is mounted on the stepped portion of the mounting surface while being inclined obliquely, the chip is guided by the lower edge supporting portion, and the inclination and rollover at the time of chip mounting can be prevented.

As described above, the production yield can be stabilized, the production cost can be reduced, and the reliability can be improved.

[Brief description of the drawings]

FIG. 1A is a perspective view illustrating a case of a solid-state imaging device according to Embodiment 1 of the present invention, and FIG. 1B is a perspective view illustrating a solid-state imaging device according to Embodiment 1 of the present invention.

FIG. 2A is a sectional view taken along line AA of FIG. 1B;
FIG. 2B is a sectional view taken along line BB of FIG.

FIG. 3 is a perspective view showing a shape of a groove according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing Embodiment 2 of the present invention.

FIG. 5 is a sectional view showing Embodiment 2 of the present invention.

FIG. 6A is a perspective view showing a first conventional example, and FIG.
Is a sectional view.

FIG. 7A is a cutaway perspective view showing a second conventional example.
(B) is a sectional view.

FIG. 8A is a perspective view showing a third conventional example, and FIG.
Is a sectional view.

FIG. 9A is a side view when a chip is sucked obliquely into a mount collet, and FIG. 9B is a cross-sectional view.

FIG. 10 is a cross-sectional view in which a chip is obliquely adhered to a mounting surface.

FIG. 11 is a cross-sectional view when a mount surface is warped and a crack occurs in a chip.

FIG. 12 is a cross-sectional view when a mount surface is warped.

FIG. 13 is a cross-sectional view when a mounting surface using a low-stress mounting material is warped.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Frame 3 External lead 4 Internal lead 5 Mounting surface 6 Depression 7a, 7b, 7c Groove 8 Chip 9 Bonding wire 10 Transparent cap 11 Adhesive 12 Mounting agent 13 Projection

Claims (5)

(57) [Claims] 1. A semiconductor device having a semiconductor element hermetically sealed in a hollow envelope body, wherein a pedestal portion, a lower edge support portion, a groove, and a groove are formed in a portion of the envelope body to which the semiconductor element is bonded. The pedestal supports the lower surface of the semiconductor element, and the lower edge support is formed by being raised on both sides of the pedestal, applied to the opposing side surfaces of the semiconductor element, and The groove is a recess formed in a region of the pedestal portion corresponding to the lower surface of the semiconductor element, and is characterized by being coated with a mounting agent for bonding the lower surface of the element to the pedestal portion. Semiconductor device. 2. A recovery groove, wherein the recovery groove collects excess mounting agent leaking from the groove and prevents the mounting agent from climbing up to the side surface of the element. Item 2. The semiconductor device according to item 1. 3. The semiconductor device according to claim 1, wherein the lower edge supporting portion is an inner wall of a recess formed surrounding the pedestal portion. 4. The semiconductor device according to claim 1, wherein the lower edge support portion is a protrusion formed to stand up around the pedestal portion. 5. The semiconductor device according to claim 1, wherein a part of the groove extends in a length direction of a lower surface of the semiconductor element.