JP2001257304A - Semiconductor device and method of mounting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the problem in which when bonding a mount substrate and lead sections planarly disposed on a bottom face of a semiconductor device through soldering, sufficient mounting strength cannot be achieved since there are only a few bonding points. SOLUTION: A recessed part 9 is formed on a side face of each lead section 2 of QFN. When bonding the lead sections 2 on the substrate using solder or the like to mount them on the substrate, a bond enters not only the bottom face and side face of the lead sections 2 but also the recessed part 9, which increases the number of bonding points. Besides increase in bonding points, the bond has an anchoring effect against the recessed part 9, so that the mounting strength can be increased markedly and an influence due to stresses applied in some conditions in which the semiconductor device is used can be eliminated, thereby the reliability of a secondary mounting can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device in which electrode terminals such as leads arranged on the bottom surface are suitable for mounting on a printed circuit board using a bonding material, and a mounting method thereof. The present invention relates to a semiconductor device capable of improving the mounting strength and improving the reliability of secondary mounting in board mounting, and a method for mounting the same.

[0002]

2. Description of the Related Art Conventionally, as a method of mounting a semiconductor device on a printed circuit board on which wiring has been formed, a lead portion disposed on the bottom surface of the semiconductor device has been mounted using solder as a bonding material.

Hereinafter, a conventional semiconductor device and a mounting method thereof will be described with reference to the drawings.

FIGS. 5 and 6 show a conventional semiconductor device mounted on a printed circuit board. FIG. 5A is a plan view, FIG. 5B is a side view, and FIG. It is a bottom view.
FIG. 6A is a perspective plan view showing the internal configuration, and FIG.
FIG. 7 is a cross-sectional view taken along the line AA1 in FIG.

A conventional semiconductor device mounted on a substrate is shown in FIG.
As shown in FIG. 1, the leads 2 are arranged on the bottom and side surfaces of the sealing resin 1 constituting the package, and the end of the suspension lead 3 is exposed at the end of the sealing resin 1. Specifically, as shown in FIG. 6, a semiconductor element 4, a die pad portion 5 supporting the semiconductor element 4, and a die pad portion 5
, A lead portion 2 having a tip portion disposed on a die pad portion 5, a thin metal wire 6 electrically connecting the lead portion 2 and the semiconductor element 4,
A semiconductor device comprising a sealing resin 1 in which a terminal portion of a suspension lead portion 3 and one side surface and a bottom surface of a lead portion 2 are exposed, and a semiconductor element 4, a die pad portion 5, and a thin metal wire 6 are sealed. . In FIG. 6, the semiconductor element 4 is shown by a broken line.

In order to mount the conventional semiconductor device configured as described above on a mounting board such as a printed board, as shown in a cross-sectional view showing a mounting structure of FIG. The side surface and the connection portions of the mounting board 7 such as electrodes and wiring are mounted using solder 8.

In other words, in the conventional mounting of the semiconductor device, the bottom and side surfaces of the lead portions 2 arranged on the bottom surface of the semiconductor device and the mounting substrate 7 are joined with the solder 8. It was implemented on the side.

[0008]

However, the conventional semiconductor device is mounted on the bottom and side surfaces of the lead portion, and the mounting strength may not be sufficient for mounting on a substrate. Was needed. That is, conventionally, the bottom surface and one exposed side surface of the lead portion arranged on the bottom surface of the semiconductor device are joined to the mounting board by soldering, and the mounting strength is insufficient because the number of joints is small. was there. Particularly, stress may be applied depending on the use state after mounting on the board, and there is a possibility that the conventional mounting structure cannot cope with such severe use conditions.

Further, QFP (Quad Flat Pac)
In the case where the lead portion protrudes from the package body as in the case of a semiconductor device such as a semiconductor device such as a semiconductor device, the bottom surface and each side surface of the lead portion can be joined with a joining material such as solder at the time of mounting on a substrate, so that a joining portion can be secured. However, recent QFNs (Quad Flat Non-leaded) in which the above-described leads are arranged on the surface can be obtained.
(Package) demanded an improvement in mounting strength. The width of the lead portion of the QFN type semiconductor device is approximately 2
Since it is 00 [μm] and the width is very small, it is necessary to improve the mounting strength.

The present invention solves the above-mentioned problems in the conventional mounting structure of a semiconductor device, and in a recent QFN type semiconductor device, dramatically improves the mounting strength and eliminates the influence of the use situation, An object of the present invention is to provide a semiconductor device capable of improving the reliability of mounting and a mounting method thereof.

[0011]

In order to solve the above-mentioned conventional problems, a semiconductor device according to the present invention is arranged such that a bottom surface of a lead portion for electrical connection is arranged on a bottom surface, and one side of the lead portion outside the lead portion is arranged on a side surface. A semiconductor device in which side surfaces are arranged, wherein the one side surface of the lead portion has a concave portion, and the convex portion forming the concave portion is a convex portion formed by a plating layer formed on the surface of the lead portion. .

Further, in the semiconductor device according to the present invention, a semiconductor element, a die pad portion supporting the semiconductor element, a suspension lead portion supporting the die pad portion at a distal end thereof, and a distal end disposed at the die pad portion are provided. A connecting portion electrically connecting the lead portion and the semiconductor element, and exposing at least one side surface and a bottom surface of the lead portion to the outside of the semiconductor device, the die pad portion, and the connecting means. A semiconductor device comprising a sealing resin sealing an enclosure, wherein a side surface of the lead portion has a concave portion, and a convex portion forming the concave portion is a convex portion formed by a plating layer formed on a surface of the lead portion. A certain semiconductor device.

More specifically, the plating device formed on the surface of the lead portion is a semiconductor device that is a laminated plating layer having a palladium layer.

The recess on the side surface of the lead portion has a size of 20 μm.
m] to 40 [μm].

Further, in the method of mounting a semiconductor device according to the present invention, there is provided a semiconductor device, a die pad portion supporting the semiconductor element, a suspension lead portion supporting the die pad portion at a tip end thereof, and a tip end portion provided at the die pad portion. The arranged lead portion, connection means for electrically connecting the lead portion and the semiconductor element, and exposing at least one outer side surface and bottom surface of the lead portion, the semiconductor element, the die pad portion, It is made of a sealing resin that seals the outer periphery of the connecting means, and one side surface outside the lead portion has a concave portion, and the convex portion forming the concave portion is formed by a plating layer formed on the surface of the lead portion. A method of mounting a semiconductor device which is a convex portion, wherein at least one side surface and a bottom surface of the lead portion of the semiconductor device are mounted on a mounting substrate with a bonding material, and the semiconductor device is mounted on the concave portion of the lead portion. By entering the mixed material, the bottom surface of the lead portion, a mounting method of a semiconductor device to be bonded on the inside of the side surface and the side surface.

As described above, since the outer side surface of the lead portion has the concave portion, the exposed bottom portion of the lead portion and the outer side surface disposed on the bottom surface of the semiconductor device are joined to each other by a bonding material. In addition to the structure that is joined to the mounting board and mounted, the joining material also enters the recess on one side of the outside, so the number of joints increases, so the mounting strength is dramatically improved and it is applied depending on the usage situation This eliminates the influence of the stresses and improves the reliability of the secondary mounting.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a semiconductor device according to the present invention and a method for mounting the same will be described below with reference to the drawings.

FIGS. 1 and 2 show a semiconductor device mounted on a printed circuit board according to this embodiment.
1A is a plan view, and FIG. 1B is a bottom view. FIG.
2A is a perspective plan view showing the internal configuration, and FIG. 2B is a cross-sectional view taken along a line BB1 in FIG. 2A.

As shown in FIG. 1, in the semiconductor device mounted on a substrate according to the present embodiment, a lead portion 2 exposes the bottom surface and one outer side surface at the end of the bottom surface of a sealing resin 1 constituting a package. The end of each of the corners of the sealing resin 1 has a structure in which the end of the suspension lead 3 is exposed.

More specifically, as shown in FIG. 2, a semiconductor element 4 and a die pad 5 supporting the semiconductor element 4 are provided.
Suspended lead 3 supporting die pad 5 at its tip
And a lead portion 2 having a tip portion disposed on a die pad portion 5.
And a thin metal wire 6 electrically connecting the lead portion 2 and the semiconductor element 4, and at least an end portion of the suspension lead portion 3 and one side surface and a bottom surface of the lead portion 2 are exposed, and the semiconductor element 4 and the die pad portion are exposed. 5, a QFN-type semiconductor device comprising a sealing resin 1 sealing the outer periphery of the fine metal wire 6. Further, the suspension lead portion 3 has a step portion (bent portion), and has a structure in which the die pad portion 5 is set up with respect to the lead portion 2. Therefore, the sealing resin 1 is present in the bottom region of the die pad portion 5 in a thickness corresponding to the upset. Further, the bottom surfaces of the lead portion 2 and the suspension lead portion 3 are projected and exposed from the surface of the sealing resin 1 by a slight protrusion amount of about 50 [μm]. In addition,
In FIG. 2, the semiconductor element 4 is indicated by a broken line.

As shown in FIG. 3, the semiconductor device of the present embodiment has a recess 9 on the side of the lead 2 exposed outside the package. FIG. 3A is a side view of the semiconductor device, and FIG. 3B is an enlarged perspective side view in a circle of FIG. 3A. As shown, the lead portion 2 of the semiconductor device of the present embodiment has a concave portion 9 on the exposed side surface, and the depth of the concave portion 9 is 20 [μm] to 40 [μ].
m], and is 30 [μm] in the present embodiment.

In the semiconductor device according to the present embodiment, since the concave portion 9 is formed on the side surface of the lead portion 2, when the substrate is mounted,
When bonding using a bonding material such as solder, the bonding material enters the recess 9 in addition to the bottom and side surfaces of the lead portion 2.
With an increase in the number of joints, the anchoring effect of the joining material on the concave part dramatically improves the mounting strength, eliminates the effects of stress applied depending on the usage conditions, and improves the reliability of secondary mounting It is.

As a method of forming the concave portion 9 on the side surface of the lead portion 2, after forming a semiconductor device, a sulfuric acid-based solution is used as an etching solution, and the lead portion 2 is immersed in the etching solution. This can be achieved by etching the inside of the side surface of the lead portion to partially remove the lead base material constituting the lead portion 2. Conditions for immersion in the etching solution are set according to the material of the lead base material and the depth of the concave portion to be formed. In the present embodiment, the shape of the concave portion 9 is a U-shaped box-shaped concave portion. However, the concave portion 9 may be a U-shaped or V-shaped concave portion, and can be adjusted by adjusting etching conditions.

In the semiconductor device of this embodiment, a copper (Cu) material is used as a base material of a lead frame, and nickel (Ni) is used as a first layer and palladium (Pd) is used as a second layer. And a third layer (uppermost layer) plated with ultra-thin gold (Au) and laminated and plated. Therefore, when the lead portion 2 is immersed in the etching solution, the lead material (Cu) that is in direct contact with the etching solution is etched due to the difference in etching rate, and the difference in etching rate acts. The recess 9 is formed on the side surface of the portion 2. Therefore, the peripheral portion constituting the concave portion 9, that is, the convex portion is a layer of the multilayer plating generally plated on the surface of the lead portion 2, and the concave portion 9 is formed since the plated layer remains without being etched. .

As a lead frame, a copper (Cu) material is used as a base material, and nickel (Ni) as a first layer, palladium (Pd) as a second layer,
When the third layer (uppermost layer) is formed by plating ultra-thin gold (Au) to form a multilayer plating, a sulfuric acid-based solution is preferable as the etchant.

The side surface (end surface) of the lead portion 2 is cut along with the laminated plating layer by cutting in a product separation process during manufacturing.
u substrate is exposed. Therefore, a difference in etching rate occurs on the side surface of the lead portion 2.

In order to mount the semiconductor device configured as described above on a mounting board such as a printed circuit board, as shown in a cross-sectional view showing the mounting structure in FIG. One side surface and a connection portion of an electrode, a wiring, etc. of the mounting substrate 7 are mounted using solder 8 of a bonding material. Further, in the present embodiment, the concave portion on the side surface of the lead portion 2, that is, the inside of the side surface of the lead portion 2 and the connection portion of the mounting substrate 7 such as the electrodes and wiring are mounted using the solder 8.

In the present embodiment, in addition to the structure in which the exposed bottom surface of the lead portion 2 disposed on the bottom surface of the semiconductor device and one outer side surface are joined to a mounting board by solder 8 and mounted, the lead portion is mounted. 2, that is, a structure in which the inside of the side surface of the lead portion 2 and the mounting substrate are joined and mounted, so that the number of joints increases, so that the mounting strength is dramatically improved and applied depending on the usage conditions. The effect of the stress can be eliminated and the reliability of the secondary mounting can be improved.

When mounting the semiconductor device on a mounting board, one side and bottom surface of the lead portion 3 of the semiconductor device are mounted with solder 8 as a bonding material, and the exposed lead portion 2 is mounted. The recesses are also mounted with solder 8, and are joined together in a solder reflow process.

As described above, in this embodiment, the QFN in which the lead portions are arranged on the bottom surface so that the bottom surface and one outer side surface are exposed.
Although the semiconductor device of the SON (Sma) type has been described as an example,
llOutline Non-leaded Pack
An age-type semiconductor device has the same effect of improving the mounting strength. Also, a semiconductor device of the type in which the die pad portion is exposed on the bottom surface has the same effect of improving the mounting strength. That is, in the case of a semiconductor device in which the lead portion is exposed on the bottom surface and the side surface of the semiconductor device, in addition to the bonding between the substrate and the bottom surface and the side surface of the lead portion, the concave portion provided on the side surface of the lead portion is formed. Also, since the bonding material such as solder can be inserted and bonded, the mounting strength can be improved. In particular, when semiconductor devices are mounted on miniaturized mobile phones in recent years, their usage becomes severe,
Even if stress due to bending or the like is applied to the mounting substrate and stress is applied to the joint, the effect can be eliminated and the reliability of the secondary mounting can be improved.

[0031]

According to the semiconductor device mounting structure and the semiconductor device mounting method of the present invention, the exposed bottom surface of the lead portion disposed on the bottom surface of the semiconductor device and one outer side surface are joined to the mounting substrate by soldering. In addition to the structure to be mounted and mounted, the concave portion on the side surface of the lead portion, that is, the inside of the side surface of the lead portion and the connection portions such as electrodes and wiring of the mounting substrate are joined to the mounting substrate using solder and mounted. Therefore, the number of joints increases, so that the mounting strength can be dramatically improved, the influence of the stress applied depending on the use condition can be eliminated, and the reliability of the secondary mounting can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a semiconductor device mounted on a board according to an embodiment of the present invention;

FIG. 2 is a diagram showing a semiconductor device mounted on a board according to an embodiment of the present invention;

FIG. 3 is a diagram showing a semiconductor device mounted on a board according to an embodiment of the present invention;

FIG. 4 is a diagram showing a mounting method of the semiconductor device according to one embodiment of the present invention;

FIG. 5 is a diagram showing a conventional semiconductor device mounted on a substrate.

FIG. 6 is a diagram showing a conventional semiconductor device mounted on a substrate.

FIG. 7 is a diagram showing a conventional semiconductor device mounting method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing resin 2 Lead part 3 Suspended lead part 4 Semiconductor element 5 Die pad part 6 Fine metal wire 7 Mounting substrate 8 Solder 9 Depression

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Narishi Ota 1-1, Sachimachi, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd. (72) Inventor Masashi Funakoshi 1-1, Sachimachi, Takatsuki-shi, Osaka Matsushita Electronics (72) Inventor Noboru Tani 1-1, Yukicho, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd. F-term (reference) 5F067 AA13 AB03 AB04 BC07 BD05 BD10 DC17 DC19 EA04

Claims (5)

[Claims] 1. A semiconductor device in which a bottom surface of a lead portion for electrical connection is arranged on a bottom surface and an outer side surface of the lead portion is arranged on a side surface, wherein the one side surface of the lead portion has a recess. The semiconductor device according to claim 1, wherein the convex portion forming the concave portion is a convex portion formed by a plating layer formed on the surface of the lead portion. 2. A semiconductor device, a die pad portion supporting the semiconductor device, a suspension lead portion supporting the die pad portion at a distal end thereof, a lead portion having a distal end portion disposed on the die pad portion, and the lead. Connecting means for electrically connecting the semiconductor device and the semiconductor element, and at least one side surface and bottom surface of the lead portion being exposed, and sealing the semiconductor element, the die pad portion, and the outer periphery of the connecting means. A semiconductor device comprising a resin, wherein a side surface of the lead portion has a concave portion, and the convex portion forming the concave portion is a convex portion formed by a plating layer formed on a surface of the lead portion. apparatus. 3. The semiconductor device according to claim 1, wherein the plating layer formed on the surface of the lead portion is a laminated plating layer having a palladium layer. 4. The concave portion on the side surface of the lead portion has a size of 20 [μm].
3. The semiconductor device according to claim 1, wherein the thickness of the semiconductor device is about 40 μm. 5. A semiconductor device, a die pad portion supporting the semiconductor device, a suspension lead portion supporting the die pad portion at a tip end thereof, a lead portion having a tip end portion arranged on the die pad portion, and the lead Connecting means for electrically connecting the semiconductor element to the semiconductor element, and exposing at least one outer side surface and bottom surface of the lead part, and sealing the outer periphery of the semiconductor element, the die pad part, and the connecting means. A method for mounting a semiconductor device, comprising: a sealing resin formed on the outer surface of a lead portion having a concave portion, and the convex portion forming the concave portion being a convex portion formed by a plating layer formed on the surface of the lead portion. And mounting at least one side surface and a bottom surface of the lead portion of the semiconductor device to a mounting board with a bonding material, and letting a bonding material enter the recess of the lead portion, A method of mounting a semiconductor device, comprising: bonding at a bottom surface, a side surface, and inside a side surface.