JPH0955405A - Flexible board and its mounting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bring a flexible board into a minute state, to bring a semiconductor device into a high density state, and to improve the productivity in a mounting technique (TAB) using a flexible board. SOLUTION: The inner leads 4, which are protruding from a semiconductor element 6, are arranged alternately from the side of the active surface of the semiconductor element 6 and the side in end part direction of the semiconductor element 6. By alternately winding the inner lead 4 from the side of the active surface of the semiconductor element and from the side in end part direction of the semiconductor element as above-mentioned, the pitch equal to the irregular electrode 7 provided on the semiconductor element 6 can be obtained even when the inner lead 4, to be provided on a flexible board 1, has the double pitch when compared with the pitch of the irregular electrode 7, which consists of Au and Cu solder, for example, of the semiconductor element, and the flexible board can be brought into a minute state. Accordingly, the short circuit generating, between the inner lead and the end part of the semiconductor element can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device using a flexible substrate, and more particularly to a structure of the flexible substrate and a mounting method of the flexible substrate and the semiconductor element.

[0002]

2. Description of the Related Art In general, a semiconductor device has a semiconductor element attached to a die pad provided on a lead frame, and an external electrode of a semiconductor chip and a terminal of the lead frame are connected by wires, respectively, which are thermoset resin such as epoxy resin. After packaging, each terminal is cut and manufactured.

However, recently, with the miniaturization and thinning of electronic equipment, the semiconductor devices used therefor are also mounted at high density. Therefore, the appearance of thin and compact semiconductor devices with miniaturized leads is desired. . In order to meet such demands, a semiconductor device is arranged in the device hole of the flexible substrate, the electrode of the semiconductor element and the inner lead of the lead provided on the flexible substrate are directly connected, and a liquid resin (for example, epoxy resin) is connected to this. A semiconductor device of a type in which a sealing agent composed of is packaged by printing, potting, or transferring has come to be used.

FIG. 3 is a plan view for explaining a conventional semiconductor device using a flexible substrate, and FIG. 4 is an AA of FIG.
FIG. 5 is a cross-sectional view taken along line @, and FIG. 5 is a cross-sectional view showing a manufacturing example of the same semiconductor device. In FIG. 3, reference numeral 1 denotes a flexible substrate having a thickness of 25 to 150 μm, in which device holes 2 having an area larger than the surface area of the semiconductor element 6 described later are provided at equal intervals in the length direction. 3 has a thickness of 18 to 35 μm and a width of 15 to 100 with high conductivity such as copper provided on the flexible substrate 1.
A large number of leads made of metal foil of about μm, some of which protrude into the device hole 2 to form free ends, forming the inner leads 4. Reference numeral 5 is a sprocket hole for carrying the flexible substrate 1. Reference numeral 6 is a semiconductor element, and 7 is a gold convex electrode provided on the semiconductor element 6. FIG. 5 is a cross-sectional view showing an example of an apparatus for mounting a semiconductor element on the flexible substrate 1 as described above, and the semiconductor element 6 mounted on the semiconductor element base 8 is positioned at a predetermined position. The flexible substrate 1 stops at the position where the device hole 2 reaches the semiconductor element 6, and aligns (aligns) the many convex electrodes 7 provided on the semiconductor element 6 with the tips of the inner leads 4 of each lead 3. ) Let me. Then, the bonding tool 11 heated to about 400 to 600 degrees is lowered to form each lead 3 at a predetermined angle and the tip of each inner lead 4 is heated and applied to each convex electrode 7 of the semiconductor element 6. Press and connect. Next, after the flexible substrate 1 is moved and wound on a reel, the semiconductor element 6, the inner leads 4, and the leads 3 are squeegee-printed, potted, transferred, or the like.
After a part of is sealed with a liquid sealing resin, the leads 3 are cut to manufacture a semiconductor device.

[0005]

In recent years, further miniaturization of semiconductor devices has been required, and in the mounting technology (TAB) using a flexible substrate, in order to achieve this, the semiconductor element itself must be miniaturized. Miniaturization and miniaturization of flexible substrates are essential. However, semiconductor elements that use dry etching (dry etching) are rapidly shrinking and becoming finer. However, the flexible substrate uses wet etching (wet etching), and the inner leads of the flexible substrate are Since it is a free end rather than a device hole, it is difficult to manufacture, and it is difficult to make it smaller than a semiconductor element.

The present invention solves such a problem, and an object thereof is to provide a flexible substrate with a finer density and a semiconductor device with a higher density.

[0007]

The flexible substrate of the present invention is characterized in that inner leads are alternately arranged from the active surface side of the semiconductor element and from the end of the semiconductor element.

[0008]

According to the above configuration of the present invention, since the inner leads of the flexible substrate are alternately arranged from the active surface side of the semiconductor element and from the end of the semiconductor device, the flexible substrate is arranged at a pitch twice that of the semiconductor element. Even if it is formed, it has the same pitch as that of the semiconductor element, and has an effect of enabling the flexible substrate to be made fine.

[0009]

The present invention will be described in detail below with reference to examples.

FIG. 1 is a plan view of a flexible substrate showing an embodiment of the present invention. In FIG. 1, 1 is a flexible substrate made of, for example, polyimide, 2 is a device hole provided in the flexible substrate, and 3 is a highly conductive metal such as Cu provided in the flexible substrate, plated with tin or Ni / Au. Leads, 4 have a width of 15 to 1
Inner leads 6 which are free ends and protrude from the device hole 2 of 00 μm, and 6 are semiconductor elements. At this time, the inner leads 4 protruding from the semiconductor element 6 are
Are alternately arranged from the active surface side of the semiconductor element 6 and from the end direction side of the semiconductor element 6 (semiconductor element edge side). In this way, the inner leads 4 are alternately routed from the active surface side of the semiconductor element and from the end direction of the semiconductor element to compare with the pitch of the convex electrodes 7 made of, for example, Au, Cu, or solder of the semiconductor element, Even if the inner leads 4 provided on the flexible substrate 1 have a double pitch, the same pitch as that of the convex electrodes 7 provided on the semiconductor element 6 can be obtained, and the miniaturization can be easily realized. . At this time, it is not necessary for all of the inner leads 4 to project from the active surface side of the semiconductor element 6 and from the end portion direction of the semiconductor element 6, and the pitch portion that requires miniaturization or the wiring lead restrictions of the flexible substrate. Moreover, you may implement only a required part. At this time, if the size of the device hole 2 is made smaller than the shape of the semiconductor element 6, it is possible to prevent contact between the end portion (edge) of the semiconductor element 6 and the inner lead 4.

FIG. 2 shows a flexible substrate according to an embodiment of the present invention and a flexible substrate for mounting a semiconductor element,
It is sectional drawing of a semiconductor element and a bonding tool. When mounting the flexible substrate of the present invention on a semiconductor element, a mounting means for bonding the aligned inner leads 4 and the convex electrodes 7 one by one, which is usually called a single point TAB method, can be mentioned. However, since the single point TAB requires time in proportion to the joining points, for example, if the semiconductor element 6 has 200 convex electrodes 7 and 200 inner leads 4 formed, the joining at one point for 0.1 seconds It takes time, and it takes 0.1 seconds × 200 = 20 seconds to mount one semiconductor element, resulting in poor productivity. In order to solve such a problem, the present invention joins by collective joining (gang bonding). For example, a Sn plating layer is provided on the inner lead 4, a large number of convex electrodes 7 formed on the semiconductor element 6 by, for example, Au plating are aligned with the tips of the inner leads 4 of the respective leads 3, and then, Lower the heated bonding tool 11 to move each lead 3
When heated and pressed to press and connect the tip of each inner lead 4 to each convex electrode 7 of the semiconductor element 6 by pressing and pressurizing, the cemented carbide, sintered diamond, boron nitride, vapor phase growth The bonding tool 11 made of a hard material such as diamond is formed narrower (smaller) than the device hole 2 provided in the flexible substrate 1. For example, the width of the device hole X is 300 μm, and the width of the convex electrode 7 is 100 μm.
Then, the width of the bonding tool Y is smaller than the device hole width X and is equal to or larger than the width of the convex electrode 7. Therefore, in the case of the above conditions, a width of about 100 to 150 μm is suitable. The bonding conditions at this time must be determined by the hardness of the convex electrodes 7, the number of inner leads 4, the material of the inner leads 4, the material plated on the inner leads 4, etc. Tool temperature: 400-600 ° C, load: 20-1
00g / lead, bonding time: 0.5-3.0
Second, if necessary, semiconductor element table temperature 8 (lower heating): 5
Conditions of about 0 to 300 ° C. are used. At this time, the bonding time is the number of inner leads 4 because the bonding is performed collectively.
Regardless of the number of the convex electrodes 7, it is possible to carry out collective bonding and the productivity is high.

[0012]

As described above, according to the present invention, by arranging the inner leads provided on the flexible substrate alternately from the semiconductor element active surface and from the semiconductor element end portion, the flexible substrate is made finer and the device hole is formed. By making it smaller than the outer shape of the semiconductor element, it has an effect of preventing edge touch (edge short circuit) between the inner lead and the semiconductor element. Further, when the flexible substrate and the semiconductor element are mounted, a concave narrow bonding tool is used to enable collective bonding, which also has the effect of improving manufacturing efficiency (cycle time).

[Brief description of drawings]

FIG. 1 is a plan view of a flexible substrate showing an embodiment of the present invention.

FIG. 2 is a mounting cross-sectional view of a flexible substrate, a semiconductor element, and a bonding tool showing an embodiment of the present invention.

FIG. 3 is a plan view of a mounting structure of a flexible substrate and a semiconductor element showing a conventional technique.

4 is a cross-sectional view taken along the line AA of FIG.

FIG. 5 is a sectional view for explaining a semiconductor device showing a conventional technique.

[Explanation of symbols]

 1 flexible substrate 2 device hole 3 lead 4 inner lead 5 sprocket hole 6 semiconductor element 7 convex electrode 8 semiconductor element stand 9 positioning guide 10 tape rail 11 bonding tool

Claims (3)

[Claims] 1. A semiconductor device is arranged on a flexible substrate,
In the semiconductor device in which the tips of the inner leads provided on the flexible substrate are connected to a large number of electrodes provided on the semiconductor element, and then the semiconductor element and a part of the leads are sealed with a resin or the like, The flexible substrate, wherein the inner leads provided on the substrate are alternately arranged from an active surface side of the semiconductor element and from an end portion of the semiconductor element. 2. A semiconductor element is arranged on a flexible substrate,
A semiconductor in which the tips of the inner leads provided on the flexible substrate are connected to a large number of electrodes provided on the semiconductor element by heating, pressurizing, etc., and then the semiconductor element and some of the leads are sealed with resin or the like. In the apparatus, the inner leads provided on the flexible substrate are arranged alternately from the active surface side of the semiconductor element and from the end of the semiconductor element, and the holes (device holes) provided in the flexible substrate are formed more than the shape of the semiconductor element. Flexible board characterized by being small. 3. A semiconductor element is arranged on a flexible substrate,
A semiconductor device in which the tips of inner leads provided on the flexible substrate are connected to a large number of electrodes provided on a semiconductor element, and then the semiconductor element and a part of the leads are sealed with a resin or the like. Alternatively, a flexible board mounting method is characterized in that when the flexible boards according to claim 2 are bonded, they are collectively bonded (gang bonding).