JP2000195982A - Compact semiconductor device, its packaging structure, and manufacture of ceramic substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact semiconductor device, its packaging structure, and a method for manufacturing a ceramic substrate used for the compact semiconductor device for improving the connection reliability at the connection part between a printed wiring board and the compact semiconductor device that changes due to usage environment or the like, in the compact semiconductor device that is surface-mounted on a printed wiring board. SOLUTION: In a compact semiconductor device 1 where a plurality of lands 5 are arranged, the lands 5 formed at a position, where the distance from the central part of the compact semiconductor device 1 is farthest, are extended to the end face of a carrier 3. Also the lands which are arranged at an outer periphery are extended to the end face of the carrier. Furthermore, in the packaging structure of the compact semiconductor device, a footprint 11, that faces opposite the land extending to the end face of the carrier, is extended to the outside from the projection surface of the compact semiconductor device 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small semiconductor device which is surface-mounted on a printed wiring board, and which improves the connection reliability of a connection portion between the printed wiring board and the small semiconductor device which changes depending on the use environment and the like. The present invention relates to a mounting structure of a small semiconductor device and a method of manufacturing a ceramic substrate used for the small semiconductor device.

[0002]

2. Description of the Related Art A small semiconductor device to be reflow soldered to a footprint of a printed wiring board is a CSP (Ch).
ip Size Package), BGA (Ball
Grid Array) package.

FIG. 6 shows a diagram of the prior art. In FIG. 1A, in a small semiconductor device, a plurality of circular lands 55 are arranged at predetermined intervals in a grid pattern on a carrier 53 made of a ceramic substrate or a resin substrate.
In FIG. 2B, in order to electrically connect the small semiconductor device to the printed wiring board 60, after applying cream solder to a footprint 61 having a shape corresponding to the land 55 formed on the printed wiring board 60, The small semiconductor device is mounted on the printed wiring board 60 so that the land 55 faces the predetermined footprint 61, and reflow soldering is performed to form a soldered portion 65.

When mounting a small semiconductor device on a printed wiring board 60, reflow soldering is performed in a high-temperature atmosphere.
For this reason, a large stress is generated in a connection portion to be soldered due to a difference in thermal expansion coefficient between the small semiconductor device and the printed wiring board 60. In particular, when a small semiconductor device using a carrier 53 formed of a ceramic substrate is mounted on a printed wiring board 60 formed of a resin substrate, the effect is remarkable because of a large difference in thermal expansion coefficient.

[0005] A printed wiring board 60 on which a small semiconductor device is mounted is stored in electronic equipment and used in various environments. 2. Description of the Related Art In recent years, electronic devices have been reduced in size with higher performance and higher functionality of small semiconductor devices, and portable electronic devices have been widely used. Therefore, users use electronic devices in all environments.

[0006] When a small semiconductor device is mounted on a printed wiring board, or when electronic equipment is used in any environment, the electrical connection between the small semiconductor device and the printed wiring board is subject to various thermal stresses and mechanical stresses. It is generally known that changes occur when subject to sexual stress.

That is, there is a difference in the thermal expansion coefficient between the small semiconductor device and the printed wiring board, and the thermal expansion coefficient of the printed wiring board 60 is larger than that of the small semiconductor device. For this reason, for example, as shown in FIG. 7A, when the electronic device is used in an environment of a high-temperature atmosphere, the expansion of the printed wiring board 60 increases, and soldering formed on both ends of the small semiconductor device 51 is performed. Portion 65 is subjected to shear forces.
Further, as shown in FIG. 7B, when the electronic device is used in a low-temperature atmosphere environment, the shrinkage of the printed wiring board 60 increases, and the soldering portions 65 formed at both ends of the small semiconductor device 51 Subject to shear forces.

[0008] Further, as shown in FIG. 7 (c), when a convex warp is generated on the printed wiring board 60 due to thermal stress or mechanical stress, soldering is performed on both ends of the small semiconductor device 51. The portion 65 receives a tensile force, and the soldered portion formed at the center of the small semiconductor device 51 receives a compressive force. Further, as shown in FIG. 7D, when a concave warp is generated in the printed wiring board 60 due to thermal stress or mechanical stress, the soldering portion 65 formed at the center of the small semiconductor device 51 is pulled. Upon receiving the force, the soldered portions formed at both ends of the small semiconductor device 51 receive a compressive force.

As shown in FIG. 8A, the soldering portions 65 formed at both ends of the small semiconductor device 51 generate shear stress and tensile stress by receiving the aforementioned shearing force and tensile force. If the shear stress or the tensile stress exceeds the limit of the strength of the soldered portion 65, cracks occur, resulting in poor connection.
Further, even when the soldering portion 65 formed at the center of the small semiconductor device 51 receives a tensile force, if the tensile stress exceeds the strength limit of the soldering portion 65, cracks occur, resulting in poor connection. When these stresses are repeatedly applied for a long period of time, cracks occur due to the creep phenomenon, resulting in poor connection.

In order to improve the connection reliability of the small semiconductor device 51, as shown in FIG. 8B, the height of the soldered portion 65 is increased, the composition of the soldered portion 65 is changed, or as shown in FIG. As shown in (c), a method of forming a resin sealing portion 66 that wraps the soldering portion 65 with a resin has been studied. However, any of these methods is complicated and the effect is small. It is not a definitive method for improving connection reliability.

[0011]

As described above, the prior art has the following problems.

1) There is no established method for improving the connection reliability at the connection between a small semiconductor device and a printed wiring board which changes depending on the environment or the like.

2) A soldering portion of a small semiconductor device mounted on the surface of a printed wiring board generates shear stress or tensile stress when subjected to thermal stress or mechanical stress, and the stress is limited to the strength of the soldering portion. If it exceeds, cracks often occur, resulting in poor connection.

3) The plurality of soldered portions of the small semiconductor device mounted on the surface of the printed wiring board all have the same strength. For this reason, a soldered portion formed at a distance far from the center of the small semiconductor device is most likely to be subjected to thermal stress or mechanical stress, and is weak against stress and has low connection reliability.

[0015]

In order to solve the above problems, the present invention takes the following measures.

A large amount of solder is formed in a soldering portion formed at a distance far from the center of the small semiconductor device which is most subjected to thermal stress and mechanical stress, and a land shape is formed so as to be strong against the stress.

In addition, a large amount of solder is formed in a soldering portion formed at a distance far from the center of a small semiconductor device which is most subjected to thermal stress and mechanical stress, and the soldering portion is formed into a fillet shape which is strong against stress. Make it a footprint shape.

Further, VIA is provided on a cutting line of the carrier so that the carrier can be formed on a ceramic substrate.
Is formed, and VIAs are cut to form lands on the side surfaces of the ceramic substrate.

By taking the above-described means, the following operation works.

Since the soldered portion formed at a distance far from the center of the small semiconductor device which is most subjected to thermal stress and mechanical stress is made strong against stress, the small semiconductor device can be subjected to thermal stress and mechanical stress. The connection reliability at the connection between the device and the printed wiring board is improved. Further, the connection reliability is further enhanced by forming the soldered portion into a fillet shape. Further, the carrier that forms the land on the side surface can be formed of a ceramic substrate.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention adopts the following embodiments.

As shown in FIG. 1, a small semiconductor device in which a plurality of lands are arranged is provided with a land 5 formed at a position farthest from the center of the small semiconductor device to the end face of the carrier 3.

Further, as shown in FIG. 1, the small-sized semiconductor device includes a land 5 arranged on the outer periphery and extending to the end face of the carrier 3.

Further, as shown in FIGS. 2 and 3, the lands 5 are provided so as to extend in the lateral direction of the carrier 3.

The carrier 3 is formed of a ceramic substrate 4.

As shown in FIG. 4, in a small semiconductor device mounting structure in which a plurality of lands are arranged, a footprint opposed to a land 20 formed at a position farthest from the center of the small semiconductor device 1 is formed. 11 is provided to extend outside the land 20.

As shown in FIGS. 1 to 3, in a mounting structure of a small semiconductor device in which a plurality of lands are arranged, a land 5 formed at a position farthest from the center of the small semiconductor device 1 is a carrier. 3 and a footprint 11 facing the land 5 is provided to extend outside the projected area of the small semiconductor device 1.

Further, in the mounting structure of the small semiconductor device, the land 5 arranged on the outer periphery is extended to the end face or the side surface of the carrier 3 and the footprint 11 facing the land 5 is made smaller than the projected area of the small semiconductor device 1. Also extends outward.

Further, as shown in FIGS. 1 to 4, the connection between the lands 5 and 20 and the footprint 11 facing the lands 5 and 20 has a soldering portion 15 forming a fillet shape.

As shown in FIG. 5, in a method of manufacturing a ceramic substrate used for a small semiconductor device, a hole is formed in a predetermined position, and the hole is filled with a conductive paste.
A step of printing a predetermined land and a pattern to form a thin ceramic substrate 4 in a single layer; and a step of firing a plurality of thin ceramic substrates 4 formed in a single layer by applying pressure and heating to sinter them. A step of forming the land 5 by cutting the laminated ceramic substrate 4 with reference to a predetermined hole processed portion filled with a conductive paste;

By employing the above-described embodiment, the following operation works.

In a small semiconductor device in which a plurality of lands are arranged, the outermost lands of the small semiconductor device are provided so as to extend in the direction of the end face or side surface of the carrier. A large amount of solder is used outside the semiconductor device to relieve thermal stress and mechanical stress.

In a mounting structure of a small semiconductor device in which a plurality of lands are arranged, a footprint opposed to a land formed at a position farthest from the center of the small semiconductor device is extended outward from the land. Accordingly, when the small semiconductor device is mounted, the amount of solder outside the small semiconductor device is increased, and the stress is reduced with respect to thermal stress and mechanical stress.

In the mounting structure of a small semiconductor device in which a plurality of lands are arranged, a land formed at a position farthest from the center of the small semiconductor device or a land arranged on the outer periphery is extended to the end face or side surface of the carrier. Along with extending, by providing a footprint facing a land formed at a position farthest from the center of the small semiconductor device or a land arranged on the outer periphery to extend outside the projected area of the small semiconductor device, When mounting a small semiconductor device, a large amount of solder is used outside the small semiconductor device to relieve thermal stress and mechanical stress.

Further, when mounting a small semiconductor device,
By forming the soldering part into a fillet shape,
Form a soldering part resistant to stress. In particular, in the case of a land extending in the lateral direction from the end face of the carrier, a higher quality fillet shape can be formed.

In a method of manufacturing a ceramic substrate used for a small semiconductor device, a VIA is provided on a cutting line of a carrier, and the VIA is cut to form an electrode (land) on a side surface of the ceramic substrate. The height of the side electrodes (lands) can be arbitrarily adjusted by changing the number of VIA layers.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical embodiment according to the present invention will be described with reference to FIGS. In the following, the same portions are denoted by the same reference numerals, and detailed description may be omitted.

FIG. 1 shows a diagram of an embodiment of the present invention.

In FIG. 1A, a small semiconductor device is
A plurality of circular lands 55 are arranged at predetermined intervals in a grid pattern on a carrier 3 made of a ceramic substrate 4. Further, the land 5 arranged on the outer periphery is formed to extend to the end face of the carrier 3. Further, the lands 5 extending to the end face of the carrier 3 may be formed only at the four corners farthest from the center of the small semiconductor device. Note that the carrier 3 may be formed of a resin substrate.

In FIG. 2B, the printed wiring board 10 on which the small semiconductor device is mounted is formed by extending the footprint 11 facing the land 5 outside the projected area of the small semiconductor device 1. . In order to electrically connect the small semiconductor device 1 to the printed wiring board 10, cream solder is applied to the lands 55 and the footprints corresponding to the lands 5 formed on the printed wiring board 10, and then the lands are fixed to predetermined positions. The small semiconductor device 1 is mounted on the printed wiring board 10 so as to face the footprint, and reflow soldering is performed to form a soldered portion 15.

At the connection between the small semiconductor device 1 and the printed wiring board 10, the connection between the land 5 formed extending to the end face of the carrier 3 and the footprint 11 facing the land 5 has a fillet shape. 16 can be formed.

FIG. 2 shows a diagram of an embodiment of the present invention.

In FIG. 3A, a small semiconductor device is
A plurality of circular lands 55 are arranged at predetermined intervals in a grid pattern on a carrier 3 made of a ceramic substrate 4. Further, the land 5 arranged on the outer periphery is formed to extend from the end face of the carrier 3 to a point in the side direction. Further, the lands 5 extending from the end face of the carrier 3 to the middle in the lateral direction may be formed only at the four corners farthest from the center of the small semiconductor device.

In FIG. 1B, the printed wiring board 10 on which the small semiconductor device is mounted and the case where the small semiconductor device 1 is electrically connected to the printed wiring board 10 are described with reference to FIG. ) Is the same as that described above, and a detailed description is omitted. In the connection portion between the small semiconductor device 1 and the printed wiring board 10, a higher quality fillet shape 16 can be formed as compared with the fillet shape described with reference to FIG.

FIG. 3 shows a diagram of an embodiment of the present invention.

In FIG. 5A, a small semiconductor device is
A plurality of circular lands 55 are arranged at predetermined intervals in a grid pattern on a carrier 3 made of a ceramic substrate 4. Further, lands 5 arranged on the outer periphery are formed so as to extend from the end face of the carrier 3 to the front and back of the carrier. Also,
The lands 5 formed so as to extend from the end face of the carrier 3 to the front and back of the carrier may be formed only at the four corners farthest from the center of the small semiconductor device.

In FIG. 1B, the printed wiring board 10 on which the small semiconductor device is mounted and the case where the small semiconductor device 1 is electrically connected to the printed wiring board 10 are described with reference to FIG. ) Is the same as that described above, and a detailed description is omitted. At the connection between the small semiconductor device 1 and the printed wiring board 10, a fillet shape 16 of higher quality can be formed as compared with the fillet shape described with reference to FIG.

FIG. 4 shows a diagram of an embodiment of the present invention.

In the figure, in the small semiconductor device 1, a plurality of circular lands 20 are arranged at predetermined intervals in a grid pattern on a carrier 3 made of a ceramic substrate or a resin substrate. On the other hand, the printed wiring board 10 on which the small semiconductor device 1 is mounted includes lands 20 arranged on the outer periphery of the lands 20 or lands formed only at four corners farthest from the center of the small semiconductor device 1. The footprint 11 opposing the land 20 is formed to extend outside the land 20.

In order to electrically connect the small semiconductor device 1 to the printed wiring board 10, cream solder is applied to the lands 20 formed on the printed wiring board 10 and the footprints corresponding to the lands 20. Thereafter, the small semiconductor device 1 is mounted on the printed wiring board 10 so that the lands face a predetermined footprint, and reflow soldering is performed to form a soldered portion 15.

At the connection between the small semiconductor device 1 and the printed wiring board 10, the land 2
The connection portion with the footprint 11 facing the land 20 formed only at the four corners farthest from the center portion of the small semiconductor device 0 or 0 can form the soldering portion 15 forming the fillet shape 16. .

In the configuration shown in FIGS. 1 to 4, the soldering portion formed at a distance far from the center of the small semiconductor device which is most subject to thermal stress and mechanical stress is small when the small semiconductor device is mounted. The amount of solder on the outside of the semiconductor device is increased, the strength of the soldered portion is increased, and stress is relieved against thermal stress and mechanical stress to improve connection reliability. Further, by forming the soldering portion into a fillet shape, a soldering portion resistant to stress is formed. In particular, in the case of a land extending to the end face of the carrier or a land extending in the lateral direction from the end face of the carrier, a large amount of solder outside the small semiconductor device can be formed, and a good-quality fillet shape can be formed. ,
Further increase connection reliability.

Next, a method of manufacturing a ceramic substrate used for a small semiconductor device will be described.

FIG. 5 shows a diagram of an embodiment of the present invention. This figure shows a manufacturing process of a ceramic substrate for forming a carrier.

In FIG. 5A, a thin ceramic substrate 4 is formed as a single layer. That is, a hole is formed in a predetermined position of each green sheet 4a of the work size, and the hole processed portion is filled with a conductive paste to form a VIA 8 for forming a land 5 described later and a VIA 9 for wiring. Thereafter, the predetermined lands 5a, 25, 55 and the pattern 6 are printed.

In FIG. 5B, thin green sheets are laminated. That is, a plurality of thin green sheets 4a formed of a single layer are baked by pressing and heating. Thereafter, the footprint 7 is printed at a predetermined position.

In FIG. 5C, a ceramic substrate is formed. That is, the laminated ceramic substrate 4 is cut with reference to the center of the VIA 8 to form the land 5 having a predetermined shape.

The height of the land 5 on the side surface can be arbitrarily adjusted by changing the number of VIA 8 layers.

[0059]

As described above, according to the present invention, the following effects can be expected.

In a small semiconductor device in which a plurality of lands are arranged, a land formed at a position furthest from the center of the small semiconductor device or a land arranged on the outer periphery is extended to the end face or side face of the carrier. Therefore, when mounting a small semiconductor device, it is possible to use a large amount of solder in a soldering portion that is most subjected to thermal stress and mechanical stress of the small semiconductor device, and to reduce a stress against thermal stress and mechanical stress. Since this can be alleviated, the connection reliability at the connection portion between the small semiconductor device and the printed wiring board, which changes depending on the environment or the like, can be improved.

In a mounting structure of a small semiconductor device in which a plurality of lands are arranged, a footprint opposed to a land formed at a position farthest from the center of the small semiconductor device is extended outward from the land. By mounting the small semiconductor device, when mounting the small semiconductor device, it is possible to increase the amount of solder in the soldered part that is most subjected to the thermal stress and the mechanical stress of the small semiconductor device, and to reduce the thermal stress and the mechanical stress. Therefore, the connection reliability at the connection portion between the small semiconductor device and the printed wiring board, which changes depending on the environment or the like, can be improved.

In a small semiconductor device mounting structure in which a plurality of lands are arranged, a land formed at a position furthest from the center of the small semiconductor device or a land arranged on the outer periphery is extended to the end face or side surface of the carrier. Along with extending, by providing a footprint facing a land formed at a position farthest from the center of the small semiconductor device or a land arranged on the outer periphery to extend outside the projected area of the small semiconductor device, When mounting a small semiconductor device, it is possible to increase the amount of solder in a soldered portion that is most subjected to thermal stress and mechanical stress of the small semiconductor device, and to reduce stress against thermal stress and mechanical stress At the connection between the small semiconductor device and the printed wiring board, which changes depending on the environment, etc. It is possible to improve the connection reliability.

Further, the connecting portion between the land and the footprint facing the land is provided with a soldering portion forming a fillet shape, so that a soldering portion resistant to stress when mounting a small semiconductor device is provided. Can be formed. In particular, in the case of a land extending in the lateral direction from the end face of the carrier, a higher quality fillet shape can be formed, so that the connection reliability at the connection between the small semiconductor device and the printed wiring board, which changes depending on the environment, can be improved. Can be enhanced.

In a method of manufacturing a ceramic substrate used for a small semiconductor device, a hole is formed at a predetermined position, the hole is filled with a conductive paste, a predetermined land and a pattern are printed, and a thin ceramic substrate is formed. Forming a single layer, pressing a plurality of thin plate-shaped ceramic substrates formed in a single layer, baking by heating, laminating in a predetermined shape, and laminating the laminated ceramic substrates with conductive paste Forming a land by cutting with reference to the filled predetermined hole processing portion, so that a VIA is provided on the cutting line of the carrier.
Since the electrodes (lands) can be formed on the side surfaces of the ceramic substrate by cutting the IA, the carrier that forms the lands on the side surfaces can be formed of the ceramic substrate. By changing the number of VIA layers,
The height of the electrode (land) on the side surface can be arbitrarily adjusted.

[Brief description of the drawings]

FIG. 1 is a diagram of an embodiment of the present invention.

FIG. 2 is a diagram of an embodiment of the present invention.

FIG. 3 is a diagram of an embodiment of the present invention.

FIG. 4 is a diagram of an embodiment of the present invention.

FIG. 5 is a diagram of an embodiment of the present invention.

FIG. 6 is a diagram of the prior art.

FIG. 7 is a diagram of the prior art.

FIG. 8 is a diagram of the prior art.

[Explanation of symbols]

 1: Small semiconductor device 3: Carrier 4: Ceramic substrate 5, 5a: Land 8: VIA 10: Printed wiring board 11: Footprint 15: Soldering part 16: Fillet shape 20: Land

Claims (9)

[Claims] 1. A small semiconductor device in which a plurality of lands are arranged, wherein a land (5) formed at a position farthest from the center of the small semiconductor device is provided extending to an end face of the carrier (3). A small semiconductor device characterized by the above-mentioned. 2. The small semiconductor device according to claim 1, wherein the small semiconductor device includes a land (5) disposed on an outer periphery and extending to an end face of the carrier (3). 3. The small semiconductor device according to claim 1, wherein the land is provided so as to extend in a lateral direction of the carrier. 4. The small semiconductor device according to claim 1, wherein said carrier is formed of a ceramic substrate. 5. A mounting structure for a small semiconductor device in which a plurality of lands are arranged, wherein a footprint (11) opposing a land (20) formed at a position farthest from a center of the small semiconductor device.
And extending outside the land (20). 6. A mounting structure for a small semiconductor device in which a plurality of lands are arranged, wherein a land (5) formed at a position farthest from the center of the small semiconductor device is extended to an end surface or a side surface of the carrier (3). And a footprint (11) facing the land (5) extending outside the projected area of the small semiconductor device (1). 7. The mounting structure of the small-sized semiconductor device, wherein a land (5) arranged on the outer periphery is extended to an end surface or a side surface of the carrier (3), and a footprint (11) facing the land (5). 7. The mounting structure of the small semiconductor device according to claim 6, further comprising: extending outside a projection area of the small semiconductor device (1). 8. A connection portion between the land (5, 20) and a footprint (11) facing the land (5, 20) includes a soldering portion (15) forming a fillet shape. A mounting structure for a small semiconductor device according to claim 5, 6 or 7. 9. A method of manufacturing a ceramic substrate used for a small semiconductor device, comprising: forming a hole in a predetermined position; filling the hole processing portion with a conductive paste; and printing a predetermined land and pattern; Forming a single layer of (4), and a plurality of thin ceramic substrates (4) formed of a single layer
Are laminated by pressing and heating to form a predetermined shape, and a land (5) is formed by cutting the laminated ceramic substrate (4) with reference to a predetermined hole processed portion filled with a conductive paste. And a process for producing a ceramic substrate.