JP2003163303A - Ic mounting board and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form lead terminals to be connected to an IC chip on an IC mounting board with high accuracy and prevent separation of the lead terminals from a mounting region in the board. <P>SOLUTION: The lead terminals 2a, 2b, 2c are formed on a plane which is at the same level as the surface (reference plane 3A1) of the mounting region 3A of the IC mounting board. Grooves 3a, 3b, 3c, 3d are each transferred to every side of the individual lead terminals 2a, 2b, 2c in the direction of the row (Y) by using a second metal mold 30 to raise accuracy of the individual lead terminals 2a, 2b, 2c in the direction of the row. A resin 3e of R-shaped cross section is provided for coverage between the edges of connecting surfaces 2a1, 2b1, 2c1 of the lead terminals 2a, 2b, 2c, respectively, and the grooves 3a, 3b, 3c, 3d. As a result, the lead terminals 2a, 2b, 2c can be adhered with larger adhesive strength, and thus the lead terminals 2a, 2b, 2c are prevented from separating. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC mounting substrate on which an IC chip is mounted, and in particular, it is possible to position and expose lead terminals with high precision in a resin mounting base. The present invention relates to an IC mounting substrate capable of surely conducting an electrode to the lead terminal and a method for manufacturing the same.

[0002]

2. Description of the Related Art Several tens to several millions of IC chips are simultaneously formed on one silicon wafer. This IC chip has a size of about 1 mm square or less, and includes a large number of transistor circuits inside. The IC
The chip is mounted on a substrate such as plastic or ceramic, and is packaged by resin molding or the like with the electrodes of the IC chip electrically connected to the lead portions on the substrate.

As a structure for electrically connecting the lead portion of the substrate and the electrode of the IC chip, for example, there is a wire bonding method. However, the wire bonding is costly and the external noise is likely to be superposed through the wire wiring. There is.

In addition, an IC on a substrate on which an IC chip is mounted
As a structure for conducting the chip and the lead part on the substrate,
There is also one in which the electrodes of the IC chip are installed on a plurality of lead portions provided in the mounting area of the substrate, and the lead portions and the electrodes are electrically connected to each other via soldering or a conductive resin. .

[0005]

However, since the IC chip is small in size and a large number of fine electrodes are arranged at narrow intervals, the fine lead portion is narrow in the mounting area of the substrate. They must be formed with an interval. Forming such a fine lead portion on a substrate with high accuracy requires a precise manufacturing process and is costly.

Further, if the lead portions are formed on the substrate so as to be displaced, or if the surfaces of the lead portions are not located on the same plane, a plurality of electrodes of the IC chip and corresponding electrodes are formed. However, there is a problem in that the respective lead portions cannot be surely conducted.

According to the present invention, the fine lead portions can be positioned and arranged with high precision in the mounting area of the substrate, and the electrodes of the IC chip can be stably connected to the respective lead portions.
An object is to provide a mounting substrate and a manufacturing method thereof.

[0008]

According to the present invention, there is provided a resin mounting base having an IC chip mounting region, and a plurality of lead terminals embedded in the mounting base. In an IC mounting substrate that is exposed side by side in the mounting area and in which the electrodes of the IC chip can be electrically connected to the surface of the lead terminal, the surface of the mounting area is provided with A groove for positioning the lead terminal with a molding die when molding the mounting base is formed therebetween.

According to the present invention, the groove provided between the lead terminals ensures that the connection surface of the lead terminal adjacent to the groove (the surface connected to the electrode of the IC chip) is mounted in the mounting base. Can be exposed to the area. Therefore, the electrodes of the IC chip and the connection surfaces of the lead terminals can be reliably connected.

In the above description, at the boundary portion between the lead terminal and the groove portion, resin bulges from the groove portion to the side end surface of the lead terminal, and the side end surface of the lead terminal is covered with the resin. Is preferred.

The curved surface of the portion covered with the resin is most preferably an R curved surface. However, it may be formed by a gently curved surface or a tapered surface.

In the above structure, since the lead terminal is fixed to the mounting area of the mounting base with a strong adhesive force, it is possible to prevent the lead terminal from easily peeling from the mounting area.

Further, in the IC mounting substrate, a hole for pressing the lead terminal when molding the mounting base is formed on the back side of the lead terminal exposed in the mounting area, from the back surface of the mounting base to the lead. It is formed so as to communicate with the back surface of the terminal.

According to the present invention, a cavity is formed between the first mold and the second mold, a metal lead terminal is inserted into the cavity, and a resin is injected into the cavity. Forming a mounting base in which the lead terminals are embedded,
At this time, in the method of manufacturing an IC mounting substrate in which the lead terminals are exposed on the surface of the mounting area of the mounting base and the electrodes of the IC chip can be connected to the lead terminals, the mounting area in the cavity is formed. The lead terminal is sandwiched between the abutting portion projectingly formed in the first mold and the recess formed in the second mold, and the lead terminal is laterally disposed in the recess. The mounting base is molded while positioning so as not to be displaced, and as a result, there is a groove portion between adjacent lead terminals on the surface of the mounting area, and the mounting base is mounted on the back side of the lead terminal located in the mounting area. The mounting base having a hole reaching the back surface of the lead terminal from the back surface side of the base is molded.

In this case, if the width dimension of the recess of the second mold is set to be larger than the width dimension of the lead terminal, when the mounting base is molded, the surface of the mounting region is cut from the groove portion. It is possible to mold the mounting base in which the resin is raised toward the side end portion of the lead terminal and the side end surface of the lead terminal is covered with the resin.

[0016]

1 is a plan view showing an IC mounting substrate as an embodiment of the present invention, FIG. 2 is a perspective view showing the IC substrate after a lead frame is cut, and FIG. 3 is an IC mounting substrate. 4A and 4B are cross-sectional views of a substrate and a mold for molding this IC mounting substrate, where A is a cross-sectional view taken along line IIIa-IIIa in FIG. 1, B is a cross-sectional view taken along line IIIb-IIIb in FIG. Is an enlarged cross-sectional view of the IC mounting substrate and the mold along line IV-IV in FIGS. 1 and 3A, and FIGS. 5A and 5B and FIGS. 6A, B and C.
FIG. 7A is a process diagram showing the manufacturing method of the IC mounting substrate. 5 and 6 show the die and the manufactured IC mounting substrate in a cross section taken along the line IIIa-IIIa in FIG.

As shown in FIG. 1, an IC mounting substrate 1A is for mounting an IC chip 10 cut from a silicon wafer, and is mainly composed of a lead frame 2 and a mounting base 3.

In the following, an IC chip 10 is in a chip state cut from a silicon wafer, an IC mounting substrate 1A (see FIG. 1) in which the lead frame 2 and the mounting base 3 are integrated, and the IC mounting. The substrate 1A for cutting the lead frame 2 is a substrate 1B for mounting an IC.
(See FIG. 2).

The size of the IC chip 10 shown in FIG. 1 is as small as 0.8 mm × 1.2 mm. I
On the surface of the C chip 10 on the connection side (the lower surface in the direction perpendicular to the paper surface), for example, a hemispherical electrode 10a having a diameter of about 0.1 mm.
Are provided (see FIG. 2).

The lead frame 2 is formed of a thin conductive metal plate such as copper or stainless steel.
The lead frame 2 includes support pieces 2A, 2B, 2 extending in the center direction from the center of four sides forming an outer frame of a substantially rectangular shape.
It has C and 2D. Each support piece 2A, 2B, 2C, 2
At the center of D, a lead terminal branched into a strip shape is formed. The support piece 2A and the support piece 2C are formed into three branches to form the lead terminals 2a, 2b and 2c and the lead terminals 2f, 2g and 2h, and the support piece 2B and the support piece 2D are formed into two branch terminals. 2d, 2e and lead terminals 2i, 2j. The total number of lead terminals 2a to 2j is the same as that of the electrode 1 of the IC chip 10.
It is formed by the same number as 0a.

Each of the lead terminals 2a to 2j is formed by a free end that becomes thinner toward the tip, and the width dimension in the arranging direction (X and Y directions) is about 0.1 mm and the thickness dimension is about 0. It is as fine as 05 mm. The tip ends of the lead terminals 2a to 2j are provided at the center of the lead frame 2 at a predetermined interval in the arrangement direction.

The mounting base 3 is formed of a resin material into a square V shape in plan view, and a mounting region 3A is provided at the bottom of the concave portion formed in the center thereof. Then, the lead terminals 2a to 2j after branch formation of the support pieces 2A, 2B, 2C, and 2D are pierced from the four outer surfaces to the inner surface of the mounting base 3 to form a bottom portion in the mounting area 3A. It is embedded in the resin. And each support piece 2A, 2B, 2
C and 2D are connected by the mounting base 3.

The relationship between the lead terminals 2a to 2j and the bottom of the mounting base 3 in the mounting region 3A will be described with reference to the sectional view of FIG.

In the sectional view of FIG. 4, the lead terminals 2a, 2b, 2c are embedded in the mounting region 3A of the mounting base 3. When the surface of the mounting area 3A is used as the reference surface 3A1,
Connection surfaces 2a1, 2b of the lead terminals 2a, 2b, 2c
1 and 2c1 are formed on the same surface as the reference surface 3A1. However, groove portions 3a, 3b, 3c, 3d are formed on the side portions of the lead terminals 2a, 2b, 2c in the arrangement direction (Y direction), respectively. That is, the lead terminal 2
a is formed between the groove portions 3a and 3b, the lead terminal 2b is formed between the groove portions 3b and 3c, and the lead terminal 2c is formed between the groove portions 3c and 3d.

The bottom of each groove 3a, 3b, 3c, 3d and the connecting surface 2a1, 2b of each lead terminal 2a, 2b, 2c.
A continuous resin material is formed between the edges of the 1 and 2 c 1 in the arrangement direction. At the boundary between the bottom of each groove 3a, 3b, 3c, 3d and each lead terminal 2a, 2b, 2c, both ends of each lead terminal 2a, 2b, 2c from the bottom of said groove 3a, 3b, 3c, 3d. The resin is bulged up to the end, and the side end portion of the lead terminal is covered with the resin. The cross-sectional shape of the resin 3e that covers the side end portion is most preferably the R curved surface, but may be, for example, a gentle curved surface or a tapered surface.

In this way, each lead terminal 2a, 2
It becomes possible to cover both end surfaces which are surfaces other than the connection surfaces 2a1, 2b1 and 2c1 of b and 2c with resin,
The adhesive force between each lead terminal 2a, 2b, 2c and the resin material forming the mounting base 3 can be enhanced. Therefore, it is possible to prevent the lead terminals 2a, 2b, 2c from peeling off from the mounting area 3A of the mounting base 3.

A method of manufacturing the above IC mounting substrate will be described. The manufacture of the IC mounting substrate is as shown in FIG. 3A and FIG. 3B.
The first mold 20 and the second mold 30 shown in are used. The first mold 20 is provided with a concave portion 21 serving as a cavity for molding the mounting base 3, and convex portions 22 and 23 are formed in the center thereof. Further, recesses 30a, 30a to be cavities for molding the mounting base 23 are formed at both ends of the second mold 30.

As shown in FIG. 4 (enlarged view of the cross section taken along the line IV-IV in FIG. 3A), the upper surface of the convex portion 22 of the first mold 20 is cut into a V-shaped cross section. , The remaining portion after cutting is the abutting portions 22a, 22b, 22
It is c. The abutting portions 22a, 22b, 22
c is provided at a predetermined interval in the arrangement (Y) direction, and the width dimension in the arrangement direction between the adjacent butting portions 22a and 22b is the same as the arrangement direction of the lead terminals 2a and 2b. Is set to the width dimension of. Similarly, the width dimension between the adjacent butting portions 22b and 22c matches the width dimension between the lead terminals 2b and 2c.

On the other hand, the abutting portions 22a, 22b, 2
On the facing surface 31 of the second mold 30 facing the 2c, the convex portions 31a, 31 arranged at a predetermined interval in the arrangement direction.
b, 31c, 31d are formed. The convex portion 31a
A concave portion 32a between the convex portion 31b and the convex portion 31b.
A concave portion 32b between the convex portion 31c and the convex portion 31c.
A concave portion 32c is formed between the convex portion 31d and the convex portion 31d. The recesses 32a, 32b, 32c face the lead terminals 2a, 2b, 2c, respectively. Further, the edges on both sides of each of the recesses 32a, 32b, 32c are formed to have an R-shaped cross section, and each of the recesses 32a, 32b, 3 is formed.
The bottom surface of 2c is formed on the same surface as the facing surface 31 of the second mold 30.

As shown in FIG. 5A, the first mold 20 and the second mold 20
The mold 30 is prepared. Then, as shown in FIG. 5B, the support pieces 2A, 2B, 2C, 2D of the lead frame 2 are sandwiched between the first die 20 and the second die 30.

Here, focusing on each of the lead terminals,
As shown in FIG. 4, the back surface on the Z2 side of each lead terminal 2a, 2b, 2c faces the abutting portions 22a, 22b, 22c of the convex portion 22 of the first mold 20, and is on the Z1 side in the figure. Since the connection surfaces 2a1, 2b1, 2c1 face the concave portions 32a, 32b, 32c of the second mold 30, the first mold 2
When the lead frame 2 is sandwiched between 0 and the second mold 30, the lead terminal 2 is inserted into the recesses 32a, 32b, 32c.
a, 2b, 2c enter, and the abutting portions 22a, 22b, 22c are further connected to the lead terminals 2a, 2 from the Z2 side in the figure.
The back surfaces on the Z2 side in the drawing of b and 2c can be pressed.

That is, the lead terminals 2a, 2b,
By sandwiching 2c from above and below, the recesses 32a, 32b,
The arrangement direction and the thickness direction of each lead terminal 2a, 2b, 2c in 32c can be positioned.

Next, as shown in FIG. 6A, a molten resin material is injected between the first and second molds 20 and 30. As shown in FIG. 6B, after the resin is cured, the first and second
By removing the molds 20 and 30 of FIG.
The C mounting substrate 1A is formed.

Here, the reference surface 3A1 of the mounting area 3A of the mounting base 3 is formed as a smooth surface by the facing surface 31 of the second mold 30, and the connecting surfaces 2a1, 2b1 of the respective lead terminals 2a, 2b, 2c. , 2c1 are formed in the same plane as the reference surface 3A1.

On the side portions of the lead terminals 2a, 2b, 2c in the arrangement direction, the protrusions 31a, 31 of the second mold 30 are formed.
Since b, 31c, and 31d are transferred, the groove portions 3a and 3
b, 3c, 3d can be formed. Further, the bottoms of the grooves 3a, 3b, 3c, 3d and the lead terminals 2
It is possible to cover between a, 2b, 2c and the edges of the connection surfaces 2a1, 2b1, 2c1 with a resin having a R-shaped cross section.

That is, each lead terminal 2a, 2b, 2c
The connection surfaces 2a1, 2b1 and 2c1 of the above are exposed in the mounting area 3A on the same surface as the reference surface 3A1 and the side end surfaces can be embedded in the resin. Therefore, the IC chip 10
The respective electrodes 10a and the respective connection surfaces 2a1, 2b1, 2c1 and the like can be surely contacted with each other, and electrical connection failure can be prevented. Moreover, each lead terminal 2a, 2
Since the adhesive area around b and 2c is increased and the adhesive strength can be strengthened, the lead terminals 2a, 2b and 2c can be prevented from peeling off.

On the surface of the mounting base 3 on the Z2 side, holes 3B and 3B are formed in the portions where the convex portions 22 and 23 of the first mold 20 are extracted.

Each lead terminal 2a, 2b, 2c has a first
Since the resin material in the second molds 20 and 30 is fixed by being hardened, the lead terminals 2a to 2j formed with a fine width dimension and thickness dimension in the mounting area 3A of the mounting base 3 are formed. The accuracy in the thickness direction (Z direction) and the arrangement direction (Y direction or X direction) can be improved.

Next, as shown in FIG. 6C, the IC chip 1
0 is mounted in the mounting area 3A of the mounting base 3 with the electrode 10a side facing downward (Z2 direction in the drawing). At this time, since the lead terminals 2a to 2j are formed on the same plane, the electrodes 10a of the IC chip 10 can be surely brought into contact with each other, and the IC chip 10 is fixed in the mounting area 3A in this state. It Then, by cutting the lead terminals 2a to 2j from the lead frame 2 along the cutting line 5 shown by the dotted line in FIG. 1, the IC mounting substrate 1B as shown in FIGS. 2 and 6C is formed.

[0040]

As described above, according to the present invention, the lead terminals can be formed with high accuracy in the mounting area of the IC mounting substrate. Moreover, peeling of the lead terminals can be prevented.

[Brief description of drawings]

FIG. 1 is a plan view showing an IC mounting substrate as an embodiment of the present invention,

FIG. 2 is a perspective view showing the IC substrate after cutting the lead frame;

3A and 3B are sectional views of an IC mounting substrate and a mold, where A is a sectional view taken along line IIIa-IIIa in FIG. 1 and B is II in FIG.
A cross-sectional view taken along line Ib-IIIb,

4 is an enlarged cross-sectional view of an IC mounting substrate and a mold taken along line IV-IV in FIGS. 1 and 3A;

5A and 5B are process diagrams showing a method for manufacturing an IC mounting substrate,

6A to 6C are process diagrams showing a method for manufacturing an IC mounting substrate,

[Explanation of symbols]

1A IC mounting board 2 lead frame 2a to 2j Lead terminals 2a1, 2a2, 2a3 Connection surface 3 Implementation base 3A mounting area 3A1 Reference plane (surface of mounting area) 10 IC chip 10a electrode 20 First mold 21 recess (cavity) 22, 23 convex 22a, 22b, 22c butting part 30 Second mold 31 Opposing surface 31a, 31b, 31c, 31d Convex portion 32a recess (cavity) 32b, 32c recess

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29L 31:34 B29L 31:34 (72) Inventor Hideaki Sato 1-7 Otsuka-cho, Yutani, Ota-ku, Tokyo Arp F-term (reference) within S Electric Co., Ltd. 4F202 AD02 AD18 AD35 AH37 CA11 CA30 CB01 CB17 CB20 CK42 CQ03 CQ05 4F206 AD02 AD18 AD35 AH37 JA07 JB17 JB20 JF05 JP30 JQ06 JQ81

Claims (5)

[Claims] 1. A mounting base made of resin having an IC chip mounting area, and a plurality of lead terminals embedded in the mounting base, wherein the plurality of lead terminals are exposed side by side in the mounting area. In the substrate for IC mounting in which the electrodes of the IC chip are electrically connectable to the surface of the lead terminal, the mounting base is formed on the surface of the mounting region between the adjacent lead terminals. A substrate for mounting an IC, characterized in that a groove portion for positioning the lead terminal with a molding die at the time of forming is formed. 2. The resin at the boundary between the lead terminal and the groove extends from the groove to the side end surface of the lead terminal, and the side end surface of the lead terminal is covered with the resin. The IC mounting substrate according to 1. 3. A hole for pressing the lead terminal when molding the mounting base is formed on the back side of the lead terminal exposed in the mounting area, and extends from the back surface of the mounting base to the back surface of the lead terminal. The IC mounting substrate according to claim 1, which is formed by: 4. A lead terminal formed by forming a cavity between a first mold and a second mold, inserting a metal lead terminal into the cavity, and injecting a resin into the cavity. A method for manufacturing an IC mounting substrate, in which a mounting base having embedded therein is formed, and at this time, the lead terminal is exposed on a surface of a mounting region of the mounting base and an electrode of an IC chip can be connected to the lead terminal. An abutting portion projectingly formed on the first mold in a portion forming the mounting area in the cavity;
The mounting base is molded while sandwiching the lead terminal with the recess formed in the mold and positioning so that the lead terminal is not displaced laterally in the recess, and as a result, the mounting base is molded. Forming the mounting base that has a groove between adjacent lead terminals on the front surface and has a hole that extends from the back surface side of the mounting base to the back surface of the lead terminal on the back side of the lead terminal located in the mounting area. A method for manufacturing a characteristic IC mounting substrate. 5. The width dimension of the recess of the second mold is
When the mounting base is molded, the resin is raised from the groove toward the side end of the lead terminal when the width of the lead terminal is set larger than that of the lead terminal when molding the mounting base. The method for manufacturing an IC mounting substrate according to claim 4, wherein a mounting base whose end surface is covered with the resin is molded.